,,steam ,,its ,,generation ,,and ,,use ,illustration ,,the ,,babcock ,,wilcox ,,co4 ,,new ,,york ,thirty-fifth ,edition #dth ,issue ,copyright1 #aiai1 by ,the ,babcock ,wilcox ,co4 99 99 99 99 99 ,bartlett ,orr ,press ,new ,york ,,the ,,babcock ,,wilcox ,,co4 #he ,,liberty ,,street1 ,,new ,,york1 ,u4 ,s4 ,a4 ,works ,,bayonne ,,new ,,jersey ,,barberton ,,ohio ,officers ,w4 ,d4 ,,hoxie1 ,president ,e4 ,h4 ,,wells1 ,chairman of the ,board ,a4 ,g4 ,,pratt1 ,vice-,president ,branch ,offices ,,atlanta ,candler ,building ,,boston #ce ,federal ,street ,,chicago ,marquette ,building ,,cincinnati ,traction ,building ,,cleveland ,new ,guardian ,building ,,denver #dce ,seventeenth ,street ,,havana1 ,,cuba #ajd ,calle de ,aguiar ,,houston ,southern ,pacific ,building ,,los ,,angeles ,i4 ,n4 ,van ,nuy's ,building ,,new ,,orleans ,shubert ,arcade ,,philadelphia ,north ,american ,building ,,pittsburgh ,farmers' ,deposit ,bank ,building ,,salt ,,lake ,,city ,kearns ,building ,,san ,,francisco ,sheldon ,building ,,seattle ,l4 ,c4 ,smith ,building ,,tucson1 ,,ariz4 ,santa ,rita ,hotel ,building ,,san ,,juan1 ,,porto ,,rico ,royal ,bank ,building ,export ,department1 ,new ,york3 ,alberto de ,verastegni1 ,director ,,telegraphic ,,address3 ,,for ,,new ,,york1 ,,gloveboxes ,,for ,,havana1 ,,babcock ,illustration3 ,works of ,the ,babcock ,wilcox ,co41 at ,bayonne1 ,new ,jersey ,illustration3 ,works of ,the ,babcock ,wilcox ,co41 at ,barberton1 ,ohio ,illustration3 ,works of ,babcock ,wilcox1 ,limited1 ,renfrew1 ,,scotland ,,babcock ,,wilcox ,limited ,,oriel ,,house1 ,,farringdon ,,street1 ,,london1 ,e4 ,c4 ,,works3 ,,renfrew1 ,,scotland ,directors ,,john ,,dewrance1 ,chairman ,,charles ,a4 ,,knight ,,arthur ,t4 ,,simpson ,j4 ,h4 ,r4 ,,kemnal ,,william ,d4 ,,hoxie ,managing ,director ,e4 ,h4 ,,wells ,,walter ,,colls1 ,secretary ,branch ,offices in ,great ,britain ,,glasgow3 #bi ,st4 ,vincent ,place ,,birmingham3 ,winchester ,house ,,cardiff3 #abi ,bute ,street ,,belfast3 ,ocean ,buildings1 ,donegal ,square1 ,e4 ,,manchester3 #cj ,cross ,street ,,middlesbrough3 ,the ,exchange ,,newcastle3 #db ,westgate ,road ,,sheffield3 #ad ,bank ,chambers1 ,fargate ,offices ,abroad ,,bombay3 ,wheeler's ,building1 ,hornby ,road1 ,fort ,,brussels3 #ahg ,rue ,royal ,,bilbao3 #a ,plaza de ,albia ,,calcutta3 ,clive ,building ,,johannesburg3 ,consolidated ,buildings ,,lima3 ,peru ,,lisbon3 #hd-hf ,rua do ,commercio ,,madrid3 ,ventura de la ,vega ,,melbourne3 #i ,william ,street ,,mexico3 #bb-bc ,tiburcio ,,milan3 #bb ,via ,principe ,umberto ,,montreal3 ,college ,street1 ,st4 ,henry ,,naples3 #ajg ,via ,santa ,lucia ,,shanghai3 #a;a ,jinkee ,road ,,sydney3 #dbg-dbi ,sussex ,street ,,tokyo3 ,japan ,,toronto3 ,traders' ,bank ,building ,representatives and ,licensees in ,,adelaide1 ,south ,australia ,,athens1 ,greece ,,auckland1 ,new ,zealand ,,bahia1 ,brazil ,,bangkok1 ,siam ,,barcelona1 ,spain ,,brunn1 ,austria ,,bucharest1 ,roumania ,,budapest1 ,hungary ,,buenos ,,ayres1 ,argentine ,rep4 ,,cairo1 ,egypt ,,chile1 ,valparaiso1 ,so4 ,america ,,christiania1 ,norway ,,colombo1 ,ceylon ,,copenhagen1 ,denmark ,,eskilstuna1 ,sweden ,,gijon1 ,spain ,,helsingfors1 ,finland ,,hengelo1 ,holland ,,kimberley1 ,south ,africa ,,moscow1 ,russia ,,perth1 ,western ,australia ,,poland1 ,berlin ,,rangoon1 ,burma ,,rio ,,de ,,janeiro1 ,brazil ,,smyrna1 ,asia ,minor ,,sourabaya1 ,java ,,st4 ,,petersburg1 ,russia ,,tammerfors1 ,finland ,,the ,,hague1 ,holland ,,telegraphic ,,address ,,for ,,all ,,offices ,,except ,,bombay ,,and ,,calcutta3 ,,babcock ,,for ,,bombay ,,and ,,calcutta3 ,,boiler ,illustration3 ,fonderies et ,ateliers de la ,courneuve1 ,chaudires ,babcock ,wilcox1 ,paris1 ,france ,,fonderies ,,et ,,ateliers ,,de ,,la ,,courneuve ,,chaudi,,res ,,babcock ,,wilcox #f ,,rue ,,laferri,,re1 ,,paris ,,works3 ,,seine--,,la ,,courneuve ,directors ,,edmond ,,dupuis ,j4 ,h4 ,r4 ,,kemnal ,,etienne ,,besson ,,ir,n,e ,,chavanne ,,charles ,a4 ,,knight ,,jules ,,lemaire ,branch ,offices ,,bordeaux3 #cj ,boulevard ,antoine ,gautier ,,lille3 #bc ,rue ,faidherbe ,,lyon3 #bh ,quai de la ,guillotier ,,marseille3 #ba ,cours ,devilliers ,,montpellier3 #a ,rue ,boussairolles ,,nancy3 #b ,rue de ,lorraine ,,st4 ,,etienne3 #ac ,rue de la ,bourse ,,representative ,,for ,,switzerland3 ,,spoerri ,,cie1 ,,zurich ,,telegraphic ,,address3 ,,babcock-,,paris ,illustration3 ,wrought-steel ,vertical ,header ,longitudinal ,drum ,babcock ,wilcox ,boiler1 ,equipped with ,babcock ,wilcox ,superheater and ,babcock ,wilcox ,chain ,grate ,stoker ,,the ,,early ,,history ,,of ,,the ,,generation ,,and ,,use ,,of ,,steam ,while the time of man's first knowledge and use of the expansive force of the vapor of water is unknown1 records show that such knowledge existed earlier than #aej ,b4 ,c4 ,in a treatise of about that time entitled ,pneumatica1 ,hero1 of ,alexander1 described not only existing devices of his predecessors and contemporaries but also an invention of his own which utilized the expansive force of steam for raising water above its natural level4 ,he clearly describes three methods in which steam might be used directly as a motive of power2 raising water by its elasticity1 elevating a weight by its expansive power and producing a rotary motion by its reaction on the atmosphere4 ,the third method1 which is known as ,hero's engine1 is described as a hollow sphere supported over a caldron or boiler by two trunnions1 one of which was hollow1 and connected the interior of the sphere with the steam space of the caldron4 ,two pipes1 open at the ends and bent at right angles1 were inserted at opposite poles of the sphere1 forming a connection between the caldron and the atmosphere4 ,heat being applied to the caldron1 the steam generated passed through the hollow trunnion to the sphere and thence into the atmosphere through the two pipes4 ,by the reaction incidental to its escape through these pipes1 the sphere was caused to rotate and here is the primitive steam reaction turbine4 ,hero makes no suggestions as to application of any of the devices he describes to a useful purpose4 ,from the time of ,hero until the late sixteenth and early seventeenth centuries1 there is no record of progress1 though evidence is found that such devices as were described by ,hero were sometimes used for trivial purposes1 the blowing of an organ or the turning of a skillet4 ,mathesius1 the ,german author1 in #aega2 ,besson1 a philosopher and mathematician at ,orleans2 ,ramelli1 in #aehh2 ,battista ,delia ,porta1 a ,neapolitan mathematician and philosopher1 in #afja2 ,decause1 the ,french engineer and architect1 in #afae2 and ,branca1 an ,italian architect1 in #afbi1 all published treatises bearing on the subject of the generation of steam4 ,to the next contributor1 ,edward ,somerset1 second ,marquis of ,worcester1 is apparently due the credit of proposing1 if not of making1 the first useful steam engine4 ,in the ,century of ,scantlings and ,inventions1 published in ,london in #affc1 he describes devices showing that he had in mind the raising of water not only by forcing it from two receivers by direct steam pressure but also for some sort of reciprocating piston actuating one end of a lever1 the other operating a pump4 ,his descriptions are rather obscure and no drawings are extant so that it is difficult to say whether there were any distinctly novel features to his devices aside from the double action4 ,while there is no direct authentic record that any of the devices he described were actually constructed1 it is claimed by many that he really built and operated a steam engine containing pistons4 ,in #afge1 ,sir ,samuel ,moreland was decorated by ,king ,charles ,,ii1 for a demonstration of a certain powerful machine to raise water4 ,though there appears to be no record of the design of this machine1 the mathematical dictionary1 published in #ahbb1 credits ,moreland with the first account of a steam engine1 on which subject he wrote a treatise that is still preserved in the ,british ,museum4 ,illustration3 #cig ,horse-power ,babcock ,wilcox ,boiler in ,course of ,erection at the ,plant of the ,crocker ,wheeler ,co41 ,ampere1 ,n4 ,j4 ,dr4 ,denys ,papin1 an ingenious ,frenchman1 invented in #afhj a steam digester for extracting marrowy1 nourishing juices from bones by enclosing them in a boiler under heavy pressure1 and finding danger from explosion1 added a contrivance which is the first safety valve on record4 ,the steam engine first became commercially successful with ,thomas ,savery4 ,in #afii1 ,savery exhibited before the ,royal ,society of ,england 7,sir ,isaac ,newton was ,president at the time71 a model engine which consisted of two copper receivers alternately connected by a three-way hand-operated valve1 with a boiler and a source of water supply4 ,when the water in one receiver had been driven out by the steam1 cold water was poured over its outside surface1 creating a vacuum through condensation and causing it to fill again while the water in the other reservoir was being forced out4 ,a number of machines were built on this principle and placed in actual use as mine pumps4 ,the serious difficulty encountered in the use of ,savery's engine was the fact that the height to which it could lift water was limited by the pressure the boiler and vessels could bear4 ,before ,savery's engine was entirely displaced by its successor1 ,newcomen's1 it was considerably improved by ,desaguliers1 who applied the ,papin safety valve to the boiler and substituted condensation by a jet within the vessel for ,savery's surface condensation4 ,in #afij1 ,papin suggested that the condensation of steam should be employed to make a vacuum beneath a cylinder which had previously been raised by the expansion of steam4 ,this was the earliest cylinder and piston steam engine and his plan took practical shape in ,newcomen's atmospheric engine4 ,papin's first engine was unworkable owing to the fact that he used the same vessel for both boiler and cylinder4 ,a small quantity of water was placed in the bottom of the vessel and heat was applied4 ,when steam formed and raised the piston1 the heat was withdrawn and the piston did work on its down stroke under pressure of the atmosphere4 ,after hearing of ,savery's engine1 ,papin developed an improved form4 ,papin's engine of #agje consisted of a displacement chamber in which a floating diaphragm or piston on top of the water kept the steam and water from direct contact4 ,the water delivered by the downward movement of the piston under pressure1 to a closed tank1 flowed in a continuous stream against the vanes of a water wheel4 ,when the steam in the displacement chamber had expanded1 it was exhausted to the atmosphere through a valve instead of being condensed4 ,the engine was1 in fact1 a non-condensing1 single action steam pump with the steam and pump cylinders in one4 ,a curious feature of this engine was a heater placed in the diaphragm4 ,this was a mass of heated metal for the purpose of keeping the steam dry or preventing condensation during expansion4 ,this device might be called the first superheater4 ,among the various inventions attributed to ,papin was a boiler with an internal fire box1 the earliest record of such construction4 ,while ,papin had neglected his earlier suggestion of a steam and piston engine to work on ,savery's ideas1 ,thomas ,newcomen1 with his assistant1 ,john ,cawley1 put into practical form ,papin's suggestion of #afij4 ,steam admitted from the boiler to a cylinder raised a piston by its expansion1 assisted by a counter-weight on the other end of a beam actuated by the piston4 ,the steam valve was then shut and the steam condensed by a jet of cold water4 ,the piston was then forced downward by atmospheric pressure and did work on the pump4 ,the condensed water in the cylinder was expelled through an escapement valve by the next entry of steam4 ,this engine used steam having pressure but little1 if any1 above that of the atmosphere4 ,illustration3 ,two ,units of #habh ,horse ,power of ,babcock ,wilcox ,boilers and ,superheaters at the ,fisk ,street ,station of the ,commonwealth ,edison ,co41 ,chicago1 ,ill41 #ej1djj ,horse ,power being ,installed in this ,station4 ,the ,commonwealth ,edison ,co4 ,operates in its ,various ,stations a ,total of #hf1jjj ,horse ,power of ,babcock ,wilcox ,boilers1 all ,fitted with ,babcock ,wilcox ,superheaters and ,equipped with ,babcock ,wilcox ,chain ,grate ,stokers ,in #agaa1 this engine was introduced into mines for pumping purposes4 ,whether its action was originally automatic or whether dependent upon the hand operation of the valves is a question of doubt4 ,the story commonly believed is that a boy1 ,humphrey ,potter1 in #agac1 whose duty it was to open and shut such valves of an engine he attended1 by suitable cords and catches attached to the beam1 caused the engine to automatically manipulate these valves4 ,this device was simplified in #agah by ,henry ,beighton1 who suspended from the bottom1 a rod called the plug-tree1 which actuated the valve by tappets4 ,by #agbe1 this engine was in common use in the collieries and was changed but little for a matter of sixty or seventy years4 ,compared with ,savery's engine1 from the aspect of a pumping engine1 ,newcomen's was a distinct advance1 in that the pressure in the pumps was in no manner dependent upon the steam pressure4 ,in common with ,savery's engine1 the losses from the alternate heating and cooling of the steam cylinder were enormous4 ,though obviously this engine might have been modified to serve many purposes1 its use seems to have been limited almost entirely to the pumping of water4 ,the rivalry between ,savery and ,papin appears to have stimulated attention to the question of fuel saving4 ,dr4 ,john ,allen1 in #agcj1 called attention to the fact that owing to the short length of time of the contact between the gases and the heating surfaces of the boiler1 nearly half of the heat of the fire was lost4 ,with a view to overcoming this loss at least partially1 he used an internal furnace with a smoke flue winding through the water in the form of a worm in a still4 ,in order that the length of passage of the gases might not act as a damper on the fire1 ,dr4 ,allen recommended the use of a pair of bellows for forcing the sluggish vapor through the flue4 ,this is probably the first suggested use of forced draft4 ,in forming an estimate of the quantity of fuel lost up the stack1 ,dr4 ,allen probably made the first boiler test4 ,toward the end of the period of use of ,newcomen's atmospheric engine1 ,john ,smeaton1 who1 about #aggj1 built and installed a number of large engines of this type1 greatly improved the design in its mechanical details4 ,illustration3 ,erie ,county ,electric ,co41 ,erie1 ,pa41 ,operating #cjhb ,horse ,power of ,babcock ,wilcox ,boilers and ,superheaters1 ,equipped with ,babcock ,wilcox ,chain ,grate ,stokers ,the improvement in boiler and engine design of ,smeaton1 ,newcomen and their contemporaries1 were followed by those of the great engineer1 ,james ,watt1 an instrument maker of ,glasgow4 ,in #agfc1 while repairing a model of ,newcomen's engine1 he was impressed by the great waste of steam to which the alternating cooling and heating of the engine gave rise4 ,his remedy was the maintaining of the cylinder as hot as the entering steam and with this in view he added a vessel separate from the cylinder1 into which the steam should pass from the cylinder and be there condensed either by the application of cold water outside or by a jet from within4 ,to preserve a vacuum in his condenser1 he added an air pump which should serve to remove the water of condensation and air brought in with the injection water or due to leakage4 ,as the cylinder no longer acted as a condenser1 he could maintain it at a high temperature by covering it with non-conducting material and1 in particular1 by the use of a steam jacket4 ,further and with the same object in view1 he covered the top of the cylinder and introduced steam above the piston to do the work previously accomplished by atmospheric pressure4 ,after several trials with an experimental apparatus based on these ideas1 ,watt patented his improvements in #agfi4 ,aside from their historical importance1 ,watt's improvements1 as described in his specification1 are to this day a statement of the principles which guide the scientific development of the steam engine4 ,his words are3 ,my method of lessening the consumption of steam1 and consequently fuel1 in fire engines1 consists of the following principles3 ,first1 ,that vessel in which the powers of steam are to be employed to work the engine1 which is called the cylinder in common fire engines1 and which ,i call the steam vessel1 must1 during the whole time the engine is at work1 be kept as hot as the steam that enters it2 first1 by enclosing it in a case of wood1 or any other materials that transmit heat slowly2 secondly1 by surrounding it with steam or other heated bodies2 and1 thirdly1 by suffering neither water nor any other substance colder than the steam to enter or touch it during that time4 ,secondly1 ,in engines that are to be worked wholly or partially by condensation of steam1 the steam is to be condensed in vessels distinct from the steam vessels or cylinders1 although occasionally communicating with them2 these vessels ,i call condensers2 and1 whilst the engines are working1 these condensers ought at least to be kept as cold as the air in the neighborhood of the engines1 by application of water or other cold bodies4 ,thirdly1 ,whatever air or other elastic vapor is not condensed by the cold of the condenser1 and may impede the working of the engine1 is to be drawn out of the steam vessels or condensers by means of pumps1 wrought by the engines themselves1 or otherwise4 ,fourthly1 ,i intend in many cases to employ the expansive force of steam to press on the pistons1 or whatever may be used instead of them1 in the same manner in which the pressure of the atmosphere is now employed in common fire engines4 ,in cases where cold water cannot be had in plenty1 the engines may be wrought by this force of steam only1 by discharging the steam into the air after it has done its office4444 ,sixthly1 ,i intend in some cases to apply a degree of cold not capable of reducing the steam to water1 but of contracting it considerably1 so that the engines shall be worked by the alternate expansion and contraction of the steam4 ,lastly1 ,instead of using water to render the pistons and other parts of the engine air and steam tight1 ,i employ oils1 wax1 resinous bodies1 fat of animals1 quick-silver and other metals in their fluid state4 ,the fifth claim was for a rotary engine1 and need not be quoted here4 ,the early efforts of ,watt are typical of those of the poor inventor struggling with insufficient resources to gain recognition and it was not until he became associated with the wealthy manufacturer1 ,mattheu ,boulton of ,birmingham1 that he met with the success upon which his present fame is based4 ,in partnership with ,boulton1 the business of the manufacture and the sale of his engines were highly successful in spite of vigorous attacks on the validity of his patents4 ,though the fourth claim of ,watt's patent describes a non-condensing engine which would require high pressures1 his aversion to such practice was strong4 ,notwithstanding his entire knowledge of the advantages through added expansion under high pressure1 he continued to use pressures not above #g pounds per square inch above the atmosphere4 ,to overcome such pressures1 his boilers were fed through a stand-pipe of sufficient height to have the column of water offset the pressure within the boiler4 ,watt's attitude toward high pressure made his influence felt long after his patents had expired4 ,illustration3 ,portion of #ifjj ,horse-power ,installation of ,babcock ,wilcox ,boilers and ,superheaters1 ,equipped with ,babcock ,wilcox ,chain ,grate ,stokers at the ,blue ,island1 ,ill41 ,plant of the ,public ,service ,co4 of ,northern ,illinois4 ,this ,company ,operates #ad1ehj ,horse ,power of ,babcock ,wilcox ,boilers and ,superheaters in its ,various ,stations ,in #aghb1 ,watt patented two other features which he had invented as early as #agfi4 ,these were the double acting engine1 that is1 the use of steam on both sides of the piston and the use of steam expansively1 that is1 the shutting off of steam from the cylinder when the piston had made but a portion of its stroke1 the power for the completion of the stroke being supplied by the expansive force of the steam already admitted4 ,he further added a throttle valve for the regulation of steam admission1 invented the automatic governor and the steam indicator1 a mercury steam gauge and a glass water column4 ,it has been the object of this brief history of the early developments in the use of steam to cover such developments only through the time of ,james ,watt4 ,the progress of the steam engine from this time through the stages of higher pressures1 combining of cylinders1 the application of steam vehicles and steamboats1 the adding of third and fourth cylinders1 to the invention of the turbine with its development and the accompanying development of the reciprocating engine to hold its place1 is one long attribute to the inventive genius of man4 ,while little is said in the biographies of ,watt as to the improvement of steam boilers1 all the evidence indicates that ,boulton and ,watt introduced the first wagon boiler1 so called because of its shape4 ,in #aghe1 ,watt took out a number of patents for variations in furnace construction1 many of which contain the basic principles of some of the modern smoke preventing furnaces4 ,until the early part of the nineteenth century1 the low steam pressures used caused but little attention to be given to the form of the boiler operated in connection with the engines above described4 ,about #ahjj1 ,richard ,trevithick1 in ,england1 and ,oliver ,evans1 in ,america1 introduced non-condensing1 and for that time1 high pressure steam engines4 ,to the initiative of ,evans may be attributed the general use of high pressure steam in the ,united ,states1 a feature which for many years distinguished ,american from ,european practice4 ,the demand for light weight and economy of space following the beginning of steam navigation and the invention of the locomotive required boilers designed and constructed to withstand heavier pressures and forced the adoption of the cylindrical form of boiler4 ,there are in use to-day many examples of every step in the development of steam boilers from the first plain cylindrical boiler to the most modern type of multi-tubular locomotive boiler1 which stands as the highest type of fire-tube boiler construction4 ,the early attempts to utilize water-tube boilers were few4 ,a brief history of the development of the boilers1 in which this principle was employed1 is given in the following chapter4 ,from this history it will be clearly indicated that the first commercially successful utilization of water tubes in a steam generator is properly attributed to ,george ,h4 ,babcock and ,stephen ,wilcox4 ,illustration3 ,copyright by ,underwood ,underwood ,woolworth ,building1 ,new ,york ,city1 ,operating #bded ,horse ,power of ,babcock ,wilcox ,boilers ,,brief ,,history ,,of ,,water-,,tube ,,boilers#a ,as stated in the previous chapter1 the first water-tube boiler was built by ,john ,blakey and was patented by him in #agff4 ,several tubes alternately inclined at opposite angles were arranged in the furnaces1 the adjacent tube ends being connected by small pipes4 ,the first successful user of water-tube boilers1 however1 was ,james ,rumsey1 an ,american inventor1 celebrated for his early experiments in steam navigation1 and it is he who may be truly classed as the originator of the water-tube boiler4 ,in #aghh he patented1 in ,england1 several forms of boilers1 some of which were of the water-tube type4 ,one had a fire box with flat top and sides1 with horizontal tubes across the fire box connecting the water spaces4 ,another had a cylindrical fire box surrounded by an annular water space and a coiled tube was placed within the box connecting at its two ends with the water space4 ,this was the first of the coil boilers4 ,another form in the same patent was the vertical tubular boiler1 practically as made at the present time4 ,illustration3 ,blakey1 #agff ,the first boiler made of a combination of small tubes1 connected at one end to a reservoir1 was the invention of another ,american1 ,john ,stevens1 in #ahjd4 ,this boiler was actually employed to generate steam for running a steamboat on the ,hudson ,river1 but like all the porcupine boilers1 of which type it was the first1 it did not have the elements of a continued success4 ,illustration3 ,john ,stevens1 #ahjd ,another form of water tube was patented in #ahje by ,john ,cox ,stevens1 a son of ,john ,stevens4 ,this boiler consisted of twenty vertical tubes1 #a inches internal diameter and #dj inches long1 arranged in a circle1 the outside diameter of which was approximately #ab inches1 connecting a water chamber at the bottom with a steam chamber at the top4 ,the steam and water chambers were annular spaces of small cross section and contained approximately #cc cubic inches4 ,the illustration shows the cap of the steam chamber secured by bolts4 ,the steam outlet pipe ,a is a pipe of one inch diameter1 the water entering through a similar aperture at the bottom4 ,one of these boilers was for a long time at the ,stevens ,institute of ,technology at ,hoboken1 and is now in the ,smithsonian ,institute at ,washington4 ,illustration3 ,john ,cox ,stevens1 #ahje ,about the same time1 ,jacob ,woolf built a boiler of large horizontal tubes1 extending across the furnace and connected at the ends to a longitudinal drum above4 ,the first purely sectional water-tube boiler was built by ,julius ,griffith1 in #ahba4 ,in this boiler1 a number of horizontal water tubes were connected to vertical side pipes1 the side pipes were connected to horizontal gathering pipes1 and these latter in turn to a steam drum4 ,in #ahbb1 ,jacob ,perkins constructed a flash boiler for carrying what was then considered a high pressure4 ,a number of cast-iron bars having #a inches annular holes through them and connected at their outer ends by a series of bent pipes1 outside of the furnace walls1 were arranged in three tiers over the fire4 ,the water was fed slowly to the upper tier by a force pump and steam in the superheated state was discharged to the lower tiers into a chamber from which it was taken to the engine4 ,illustration3 ,joseph ,eve1 #ahbe ,the first sectional water-tube boiler1 with a well-defined circulation1 was built by ,joseph ,eve1 in #ahbe4 ,the sections were composed of small tubes with a slight double curve1 but being practically vertical1 fixed in horizontal headers1 which headers were in turn connected to a steam space above and a water space below formed of larger pipes4 ,the steam and water spaces were connected by outside pipes to secure a circulation of the water up through the sections and down through the external pipes4 ,in the same year1 ,john ,m',curdy of ,new ,york1 built a ,duplex ,steam ,generator of tubes of wrought or cast iron or other material arranged in several horizontal rows1 connected together alternately at the front and rear by return bends4 ,in the tubes below the water line were placed interior circular vessels closed at the ends in order to expose a thin sheet of water to the action of the fire4 ,illustration3 ,gurney1 #ahbf ,in #ahbf1 ,goldsworthy ,gurney built a number of boilers1 which he used on his steam carriages4 ,a number of small tubes were bent into the shape of a ,u laid sidewise and the ends were connected with larger horizontal pipes4 ,these were connected by vertical pipes to permit of circulation and also to a vertical cylinder which served as a steam and water reservoir4 ,in #ahbh1 ,paul ,steenstrup made the first shell boiler with vertical water tubes in the large flues1 similar to the boiler known as the ,martin and suggesting the ,galloway4 ,the first water-tube boiler having fire tubes within water tubes was built in #ahcj1 by ,summers ,ogle4 ,horizontal connections at the top and bottom were connected by a series of vertical water tubes1 through which were fire tubes extending through the horizontal connections1 the fire tubes being held in place by nuts1 which also served to make the joint4 ,illustration3 ,stephen ,wilcox1 #ahef ,stephen ,wilcox1 in #ahef1 was the first to use inclined water tubes connecting water spaces at the front and rear with a steam space above4 ,the first to make such inclined tubes into a sectional form was ,twibill1 in #ahfe4 ,he used wrought-iron tubes connected at the front and rear with standpipes through intermediate connections4 ,these standpipes carried the system to a horizontal cross drum at the top1 the entrained water being carried to the rear4 ,clarke1 ,moore1 ,mc,dowell1 ,alban and others worked on the problem of constructing water-tube boilers1 but because of difficulties of construction involved1 met with no practical success4 ,illustration3 ,twibill1 #ahfe ,it may be asked why water-tube boilers did not come into more general use at an early date1 that is1 why the number of water-tube boilers built was so small in comparison to the number of shell boilers4 ,the reason for this is found in the difficulties involved in the design and construction of water-tube boilers1 which design and construction required a high class of engineering and workmanship1 while the plain cylindrical boiler is comparatively easy to build4 ,the greater skill required to make a water-tube boiler successful is readily shown in the great number of failures in the attempts to make them4 ,illustration3 ,partial ,view of #gjjj ,horse-power ,installation of ,babcock ,wilcox ,boilers at the ,philadelphia1 ,pa41 ,plant of the ,baldwin ,locomotive ,works4 ,this ,company ,operates in its ,various ,plants a ,total of #ibhj ,horse ,power of ,babcock ,wilcox ,boilers ,,requirements ,,of ,,steam ,,boilers ,since the first appearance in ,steam of the following ,requirements of a ,perfect ,steam ,boiler1 the list has been copied many times either word for word or clothed in different language and applied to some specific type of boiler design or construction4 ,in most cases1 although full compliance with one or more of the requirements was structurally impossible1 the reader was left to infer that the boiler under consideration possessed all the desirable features4 ,it is noteworthy that this list of requirements1 as prepared by ,george ,h4 ,babcock and ,stephen ,wilcox1 in #ahge1 represents the best practice of to-day4 ,moreover1 coupled with the boiler itself1 which is used in the largest and most important steam generating plants throughout the world1 the list forms a fitting monument to the foresight and genius of the inventors4 ,,requirements ,,of ,a ,,perfect ,,steam ,,boiler #ast4 ,proper workmanship and simple construction1 using materials which experience has shown to be the best1 thus avoiding the necessity of early repairs4 #bnd4 ,a mud drum to receive all impurities deposited from the water1 and so placed as to be removed from the action of the fire4 #crd4 ,a steam and water capacity sufficient to prevent any fluctuation in steam pressure or water level4 #dth4 ,a water surface for the disengagement of the steam from the water1 of sufficient extent to prevent foaming4 #eth4 ,a constant and thorough circulation of water throughout the boiler1 so as to maintain all parts at the same temperature4 #fth4 ,the water space divided into sections so arranged that1 should any section fail1 no general explosion can occur and the destructive effects will be confined to the escape of the contents4 ,large and free passages between the different sections to equalize the water line and pressure in all4 #gth4 ,a great excess of strength over any legitimate strain1 the boiler being so constructed as to be free from strains due to unequal expansion1 and1 if possible1 to avoid joints exposed to the direct action of the fire4 #hth4 ,a combustion chamber so arranged that the combustion of the gases started in the furnace may be completed before the gases escape to the chimney4 #ith4 ,the heating surface as nearly as possible at right angles to the currents of heated gases1 so as to break up the currents and extract the entire available heat from the gases4 #ajth4 ,all parts readily accessible for cleaning and repairs4 ,this is a point of the greatest importance as regards safety and economy4 #aath4 ,proportioned for the work to be done1 and capable of working to its full rated capacity with the highest economy4 #abth4 ,equipped with the very best gauges1 safety valves and other fixtures4 ,the exhaustive study made of each one of these requirements is shown by the following extract from a lecture delivered by ,mr4 ,geo4 ,h4 ,babcock at ,cornell ,university in #ahij upon the subject3 ,,the ,,circulation ,,of ,,water ,,in ,,steam ,,boilers ,you have all noticed a kettle of water boiling over the fire1 the fluid rising somewhat tumultuously around the edges of the vessel1 and tumbling toward the center1 where it descends4 ,similar currents are in action while the water is simply being heated1 but they are not perceptible unless there are floating particles in the liquid4 ,these currents are caused by the joint action of the added temperature and two or more qualities which the water possesses4 #ast4 ,water1 in common with most other substances1 expands when heated2 a statement1 however1 strictly true only when referred to a temperature above #ci degrees ,f4 or #d degrees ,c41 but as in the making of steam we rarely have to do with temperatures so low as that1 we may1 for our present purposes1 ignore that exception4 #bnd4 ,water is practically a non-conductor of heat1 though not entirely so4 ,if ice-cold water was kept boiling at the surface the heat would not penetrate sufficiently to begin melting ice at a depth of #c inches in less than about two hours4 ,as1 therefore1 the heated water cannot impart its heat to its neighboring particles1 it remains expanded and rises by its levity1 while colder portions come to be heated in turn1 thus setting up currents in the fluid4 ,now1 when all the water has been heated to the boiling point corresponding to the pressure to which it is subjected1 each added unit of heat converts a portion1 about #g grains in weight1 into vapor1 greatly increasing its volume2 and the mingled steam and water rises more rapidly still1 producing ebullition such as we have noticed in the kettle4 ,so long as the quantity of heat added to the contents of the kettle continues practically constant1 the conditions remain similar to those we noticed at first1 a tumultuous lifting of the water around the edges1 flowing toward the center and thence downward2 if1 however1 the fire be quickened1 the upward currents interfere with the downward and the kettle boils over 7,fig4 #a74 ,illustration3 ,fig4 #a ,if now we put in the kettle a vessel somewhat smaller 7,fig4 #b7 with a hole in the bottom and supported at a proper distance from the side so as to separate the upward from the downward currents1 we can force the fires to a very much greater extent without causing the kettle to boil over1 and when we place a deflecting plate so as to guide the rising column toward the center it will be almost impossible to produce that effect4 ,this is the invention of ,perkins in #ahca and forms the basis of very many of the arrangements for producing free circulation of the water in boilers which have been made since that time4 ,it consists in dividing the currents so that they will not interfere each with the other4 ,illustration3 ,fig4 #b ,but what is the object of facilitating the circulation of water in boilers8 ,why may we not safely leave this to the unassisted action of nature as we do in culinary operations8 ,we may1 if we do not care for the three most important aims in steam-boiler construction1 namely1 efficiency1 durability1 and safety1 each of which is more or less dependent upon a proper circulation of the water4 ,as for efficiency1 we have seen one proof in our kettle4 ,when we provided means to preserve the circulation1 we found that we could carry a hotter fire and boil away the water much more rapidly than before4 ,it is the same in a steam boiler4 ,and we also noticed that when there was nothing but the unassisted circulation1 the rising steam carried away so much water in the form of foam that the kettle boiled over1 but when the currents were separated and an unimpeded circuit was established1 this ceased1 and a much larger supply of steam was delivered in a comparatively dry state4 ,thus1 circulation increases the efficiency in two ways3 it adds to the ability to take up the heat1 and decreases the liability to waste that heat by what is technically known as priming4 ,there is yet another way in which1 incidentally1 circulation increases efficiency of surface1 and that is by preventing in a greater or less degree the formation of deposits thereon4 ,most waters contain some impurity which1 when the water is evaporated1 remains to incrust the surface of the vessel4 ,this incrustation becomes very serious sometimes1 so much so as to almost entirely prevent the transmission of heat from the metal to the water4 ,it is said that an incrustation of only one-eighth inch will cause a loss of #be per cent in efficiency1 and this is probably within the truth in many cases4 ,circulation of water will not prevent incrustation altogether1 but it lessens the amount in all waters1 and almost entirely so in some1 thus adding greatly to the efficiency of the surface4 ,illustration3 ,fig4 #c ,a second advantage to be obtained through circulation is durability of the boiler4 ,this it secures mainly by keeping all parts at a nearly uniform temperature4 ,the way to secure the greatest freedom from unequal strains in a boiler is to provide for such a circulation of the water as will insure the same temperature in all parts4 #crd4 ,safety follows in the wake of durability1 because a boiler which is not subject to unequal strains of expansion and contraction is not only less liable to ordinary repairs1 but also to rupture and disastrous explosion4 ,by far the most prolific cause of explosions is this same strain from unequal expansions4 ,illustration3 ,fig4 #d ,illustration3 #chf ,horse-power ,installation of ,babcock ,wilcox ,boilers at ,b4 ,f4 ,keith's ,theatre1 ,boston1 ,mass4 ,having thus briefly looked at the advantages of circulation of water in steam boilers1 let us see what are the best means of securing it under the most efficient conditions ,we have seen in our kettle that one essential point was that the currents should be kept from interfering with each other4 ,if we could look into an ordinary return tubular boiler when steaming1 we should see a curious commotion of currents rushing hither and thither1 and shifting continually as one or the other contending force gained a momentary mastery4 ,the principal upward currents would be found at the two ends1 one over the fire and the other over the first foot or so of the tubes4 ,between these1 the downward currents struggle against the rising currents of steam and water4 ,at a sudden demand for steam1 or on the lifting of the safety valve1 the pressure being slightly reduced1 the water jumps up in jets at every portion of the surface1 being lifted by the sudden generation of steam throughout the body of water4 ,you have seen the effect of this sudden generation of steam in the well-known experiment with a ,florence flask1 to which a cold application is made while boiling water under pressure is within4 ,you have also witnessed the geyser-like action when water is boiled in a test tube held vertically over a lamp 7,fig4 #c74 ,illustration3 ,fig4 #e ,if now we take a ,u-tube depending from a vessel of water 7,fig4 #d7 and apply the lamp to one leg a circulation is at once set up within it1 and no such spasmodic action can be produced4 ,thus ,u-tube is the representative of the true method of circulation within a water-tube boiler properly constructed4 ,we can1 for the purpose of securing more heating surface1 extend the heated leg into a long incline 7,fig4 #e71 when we have the well-known inclined-tube generator4 ,now1 by adding other tubes1 we may further increase the heating surface 7,fig4 #f71 while it will still be the ,u-tube in effect and action4 ,in such a construction the circulation is a function of the difference in density of the two columns4 ,its velocity is measured by the well-known ,torricellian formula1 ,v 7#b;gh71 or1 approximately ,v #h7;h71 h being measured in terms of the lighter fluid4 ,this velocity will increase until the rising column becomes all steam1 but the quantity or weight circulated will attain a maximum when the density of the mingled steam and water in the rising column becomes one-half that of the solid water in the descending column which is nearly coincident with the condition of half steam and half water1 the weight of the steam being very slight compared to that of the water4 ,illustration3 ,fig4 #f ,it becomes easy by this rule to determine the circulation in any given boiler built on this principle1 provided the construction is such as to permit a free flow of the water4 ,of course1 every bend detracts a little and something is lost in getting up the velocity1 but when the boiler is well arranged and proportioned these retardations are slight4 ,let us take for example one of the #bdj horse-power ,babcock ,wilcox boilers here in the ,university4 ,the height of the columns may be taken as #d feet1 measuring from the surface of the water to about the center of the bundle of tubes over the fire1 and the head would be equal to this height at the maximum of circulation4 ,we should1 therefore1 have a velocity of #h7d7 #af4ig1 say #ag feet per second4 ,there are in this boiler fourteen sections1 each having a #d-;inch tube opening into the drum1 the area of which 7inside7 is #aa square inches1 the fourteen aggregating #aed square inches1 or #a4jg square feet4 ,this multiplied by the velocity1 #af4ig feet1 gives #ah4af cubic feet mingled steam and water discharged per second1 one-half of which1 or #i4jh cubic feet1 is steam4 ,assuming this steam to be at #ajj pounds gauge pressure1 it will weigh #j4beh pound per cubic foot4 ,hence1 #b4cd pounds of steam will be discharged per second1 and #h1dcc pounds per hour4 ,dividing this by #cj1 the number of pounds representing a boiler horse power1 we get #bha4a horse power1 about #ag per cent1 in excess of the rated power of the boiler4 ,the water at the temperature of steam at #ajj pounds pressure weighs #ef pounds per cubic foot1 and the steam #j4beh pound1 so that the steam forms but #a_/bah part of the mixture by weight1 and consequently each particle of water will make #bah circuits before being evaporated when working at this capacity1 and circulating the maximum weight of water through the tubes4 ,illustration3 ,a ,portion of #ifjj ,horse-power ,installation of ,babcock ,wilcox ,boilers and ,superheaters ,being ,erected at the ,south ,boston1 ,mass41 ,station of the ,boston ,elevated ,railway ,co4 ,this ,company ,operates in its ,various ,stations a ,total of #df1djj ,horse ,power of ,babcock ,wilcox ,boilers ,illustration3 ,fig4 #g ,it is evident that at the highest possible velocity of exit from the generating tubes1 nothing but steam will be delivered and there will be no circulation of water except to supply the place of that evaporated4 ,let us see at what rate of steaming this would occur with the boiler under consideration4 ,we shall have a column of steam1 say #d feet high on one side and an equal column of water on the other4 ,assuming1 as before1 the steam at #ajj pounds and the water at same temperature1 we will have a head of #hff feet of steam and an issuing velocity of #bce4e feet per second4 ,this multiplied by #a4jg square feet of opening by #c1fjj seconds in an hour1 and by #j4beh gives #bcd1jdc pounds of steam1 which1 though only one-eighth the weight of mingled steam and water delivered at the maximum1 gives us #g1hja horse power1 or #cb times the rated power of the boiler4 ,of course1 this is far beyond any possibility of attainment1 so that it may be set down as certain that this boiler cannot be forced to a point where there will not be an efficient circulation of the water4 ,by the same method of calculation it may be shown that when forced to double its rated power1 a point rarely expected to be reached in practice1 about two-thirds the volume of mixture of steam and water delivered into the drum will be steam1 and that the water will make #aaj circuits while being evaporated4 ,also that when worked at only about one-quarter its rated capacity1 one-fifth of the volume will be steam and the water will make the rounds #hgj times before it becomes steam4 ,you will thus see that in the proportions adopted in this boiler there is provision for perfect circulation under all the possible conditions of practice4 ,illustration3 ,fig4 #h ,developed to show ,circulation ,in designing boilers of this style it is necessary to guard against having the uptake at the upper end of the tubes too large1 for if sufficiently large to allow downward currents therein1 the whole effect of the rising column in increasing the circulation in the tubes is nullified 7,fig4 #g74 ,this will readily be seen if we consider the uptake very large when the only head producing circulation in the tubes will be that due to the inclination of each tube taken by itself4 ,this objection is only overcome when the uptake is so small as to be entirely filled with the ascending current of mingled steam and water4 ,it is also necessary that this uptake should be practically direct1 and it should not be composed of frequent enlargements and contractions4 ,take1 for instance1 a boiler well known in ,europe1 copied and sold here under another name4 ,it is made up of inclined tubes secured by pairs into boxes at the ends1 which boxes are made to communicate with each other by return bends opposite the ends of the tubes4 ,these boxes and return bends form an irregular uptake1 whereby the steam is expected to rise to a reservoir above4 ,you will notice 7,fig4 #h7 that the upward current of steam and water in the return bend meets and directly antagonizes the upward current in the adjoining tube4 ,only one result can follow4 ,if their velocities are equal1 the momentum of both will be neutralized and all circulation stopped1 or1 if one be stronger1 it will cause a back flow in the other by the amount of difference in force1 with practically the same result4 ,illustration3 #dhhj ,horse-power ,installation of ,babcock ,wilcox ,boilers at the ,open ,hearth ,plant of the ,cambria ,steel ,co41 ,johnstown1 ,pa4 ,this ,company ,operates a ,total of #eb1jjj ,horse ,power of ,babcock ,wilcox ,boilers ,illustration3 ,fig4 #i ,in a well-known boiler1 many of which were sold1 but of which none are now made and a very few are still in use1 the inventor claimed that the return bends and small openings against the tubes were for the purpose of restricting the circulation and no doubt they performed well that office2 but excepting for the smallness of the openings they were not as efficient for that purpose as the arrangement shown in ,fig4 #h4 ,illustration3 ,fig4 #aj ,another form of boiler1 first invented by ,clarke or ,crawford1 and lately revived1 has the uptake made of boxes into which a number1 generally from two to four tubes1 are expanded1 the boxes being connected together by nipples 7,fig4 #i74 ,it is a well-known fact that where a fluid flows through a conduit which enlarges and then contracts1 the velocity is lost to a greater or less extent at the enlargements1 and has to be gotten up again at the contractions each time1 with a corresponding loss of head4 ,the same thing occurs in the construction shown in ,fig4 #i4 ,the enlargements and contractions quite destroy the head and practically overcome the tendency of the water to circulate4 ,a horizontal tube stopped at one end1 as shown in ,fig4 #aj1 can have no proper circulation within it4 ,if moderately driven1 the water may struggle in against the issuing steam sufficiently to keep the surface covered1 but a slight degree of forcing will cause it to act like the test tube in ,fig4 #c1 and the more there are of them in a given boiler the more spasmodic will be its working4 ,the experiment with our kettle 7,fig4 #b7 gives the clue to the best means of promoting circulation in ordinary shell boilers4 ,steenstrup or ,martin and ,galloway water tubes placed in such boilers also assist in directing the circulation therein1 but it is almost impossible to produce in shell boilers1 by any means the circulation of all the water in one continuous round1 such as marks the well-constructed water-tube boiler4 ,as ,i have before remarked1 provision for a proper circulation of water has been almost universally ignored in designing steam boilers1 sometimes to the great damage of the owner1 but oftener to the jeopardy of the lives of those who are employed to run them4 ,the noted case of the ,montana and her sister ship1 where some #cjj1jjj was thrown away in trying an experiment which a proper consideration of this subject would have avoided1 is a case in point2 but who shall count the cost of life and treasure not1 perhaps1 directly traceable to1 but1 nevertheless1 due entirely to such neglect in design and construction of the thousands of boilers in which this necessary element has been ignored8 ,in the light of the performance of the exacting conditions of present day power-plant practice1 a review of this lecture and of the foregoing list of requirements reveals the insight of the inventors of the ,babcock ,wilcox boiler into the fundamental principles of steam generator design and construction4 ,since the ,babcock ,wilcox boiler became thoroughly established as a durable and efficient steam generator1 many types of water-tube boilers have appeared on the market4 ,most of them1 failing to meet enough of the requirements of a perfect boiler1 have fallen by the wayside1 while a few failing to meet all of the requirements1 have only a limited field of usefulness4 ,none have been superior1 and in the most cases the most ardent admirers of other boilers have been satisfied in looking up to the ,babcock ,wilcox boiler as a standard and in claiming that the newer boilers were just as good4 ,records of recent performances under the most severe conditions of services on land and sea1 show that the ,babcock ,wilcox boiler can be run continually and regularly at higher overloads1 with higher efficiency1 and lower upkeep cost than any other boiler on the market4 ,it is especially adapted for power-plant work where it is necessary to use a boiler in which steam can be raised quickly and the boiler placed on the line either from a cold state or from a banked fire in the shortest possible time1 and with which the capacity1 with clean feed water1 will be largely limited by the amount of coal that can be burned in the furnace4 ,the distribution of the circulation through the separate headers and sections and the action of the headers in forcing a maximum and continuous circulation in the lower tubes1 permit the operation of the ,babcock ,wilcox boiler without objectionable priming1 with a higher degree of concentration of salts in the water than is possible in any other type of boiler4 ,repeated daily performances at overloads have demonstrated beyond a doubt the correctness of ,mr4 ,babcock's computation regarding the circulating tube and header area required for most efficient circulation4 ,they also have proved that enlargement of the area of headers and circulating tubes beyond a certain point diminishes the head available for causing circulation and consequently limits the ability of the boiler to respond to demands for overloads4 ,in this lecture ,mr4 ,babcock made the prediction that with the circulating tube area proportioned in accordance with the principles laid down1 the ,babcock ,wilcox boiler could be continuously run at double its nominal rating1 which at that time was based on #ab square feet of heating surface per horse power4 ,this prediction is being fulfilled daily in all the large and prominent power plants in this country and abroad1 and it has been repeatedly demonstrated that with clean water and clean tube surfaces it is possible to safely operate at over #cjj per cent of the nominal rating4 ,in the development of electrical power stations it becomes more and more apparent that it is economical to run a boiler at high ratings during the times of peak loads1 as by so doing the lay-over losses are diminished and the economy of the plant as a whole is increased4 ,the number and importance of the large electric lighting and power stations constructed during the last ten years that are equipped with ,babcock ,wilcox boilers1 is a most gratifying demonstration of the merit of the apparatus1 especially in view of their satisfactory operation under conditions which are perhaps more exacting than those of any other service4 ,time1 the test of all1 results with boilers as with other things1 in the survival of the fittest4 ,when judged on this basis the ,babcock ,wilcox boiler stands pre-eminent in its ability to cover the whole field of steam generation with the highest commercial efficiency obtainable4 ,year after year the ,babcock ,wilcox boiler has become more firmly established as the standard of excellence in the boiler making art4 ,illustration3 ,south ,boston ,station of the ,boston ,elevated ,ry4 ,co41 ,boston1 ,mass4 #ifjj ,horse ,power of ,babcock ,wilcox ,boilers and ,superheaters ,installed in this ,station ,illustration3 #cfjj ,horse-power ,installation of ,babcock ,wilcox ,boilers at the ,phipps ,power ,house of the ,duquesne ,light ,company1 ,pittsburgh1 ,pa4 ,,evolution ,,of ,,the ,,babcock ,,wilcox ,,water-,,tube ,,boiler ,quite as much may be learned from the records of failures as from those of success4 ,where a device has been once fairly tried and found to be imperfect or impracticable1 the knowledge of that trial is of advantage in further investigation4 ,regardless of the lesson taught by failure1 however1 it is an almost every-day occurrence that some device or construction which has been tried and found wanting1 if not worthless1 is again introduced as a great improvement upon a device which has shown by its survival to be the fittest4 ,the success of the ,babcock ,wilcox boiler is due to many years of constant adherence to one line of research1 in which an endeavor has been made to introduce improvements with the view to producing a boiler which would most effectively meet the demands of the times4 ,during the periods that this boiler has been built1 other companies have placed on the market more than thirty water-tube or sectional water-tube boilers1 most of which1 though they may have attained some distinction and sale1 have now entirely disappeared4 ,the following incomplete list will serve to recall the names of some of the boilers that have had a vogue at various times1 but which are now practically unknown3 ,dimpfel1 ,howard1 ,griffith ,wundrum1 ,dinsmore1 ,miller ,fire ,box1 ,miller ,american1 ,miller ,internal ,tube1 ,miller ,inclined ,tube1 ,phleger1 ,weigant1 the ,lady ,verner1 the ,allen1 the ,kelly1 the ,anderson1 the ,rogers ,black1 the ,eclipse or ,kilgore1 the ,moore1 the ,baker ,smith1 the ,renshaw1 the ,shackleton1 the ,duplex1 the ,pond ,bradford1 the ,whittingham1 the ,bee1 the ,hazleton or ,common ,sense1 the ,reynolds1 the ,suplee or ,luder1 the ,babbit1 the ,reed1 the ,smith1 the ,standard1 etc41 etc4 ,it is with the object of protecting our customers and friends from loss through purchasing discarded ideas that there is given on the following pages a brief history of the development of the ,babcock ,wilcox boiler as it is built to-day4 ,the illustrations and brief descriptions indicate clearly the various designs and constructions that have been used and that have been replaced1 as experience has shown in what way improvement might be made4 ,they serve as a history of the experimental steps in the development of the present ,babcock ,wilcox boiler1 the value and success of which1 as a steam generator1 is evidenced by the fact that the largest and most discriminating users continue to purchase them after years of experience in their operation4 ,illustration3 ,no4 #a ,no4 #a4 ,the original ,babcock ,wilcox boiler was patented in #ahfg4 ,the main idea in its design was safety1 to which all other features were sacrificed wherever they conflicted4 ,the boiler consisted of a nest of horizontal tubes1 serving as a steam and water reservoir1 placed above and connected at each end by bolted joints to a second nest of inclined heating tubes filled with water4 ,the tubes were placed one above the other in vertical rows1 each row and its connecting end forming a single casting4 ,hand-holes were placed at each end for cleaning4 ,internal tubes were placed within the inclined tubes with a view to aiding circulation4 ,no4 #b4 ,this boiler was the same as ,no4 #a1 except that the internal circulating tubes were omitted as they were found to hinder rather than help the circulation4 ,nos4 #a and #b were found to be faulty in both material and design1 cast metal proving unfit for heating surfaces placed directly over the fire1 as it cracked as soon as any scale formed4 ,no4 #c4 ,wrought-iron tubes were substituted for the cast-iron heating tubes1 the ends being brightened1 laid in moulds1 and the headers cast on4 ,the steam and water capacity in this design were insufficient to secure regularity of action1 there being no reserve upon which to draw during firing or when the water was fed intermittently4 ,the attempt to dry the steam by superheating it in the nest of tubes forming the steam space was found to be impracticable4 ,the steam delivered was either wet1 dry or superheated1 according to the rate at which it was being drawn from the boiler4 ,sediment was found to lodge in the lowermost point of the boiler at the rear end and the exposed portions cracked off at this point when subjected to the furnace heat4 ,illustration3 ,no4 #d ,no4 #d4 ,a plain cylinder1 carrying the water line at its center and leaving the upper half for steam space1 was substituted for the nest of tubes forming the steam and water space in ,nos4 #a1 #b and #c4 ,the sections were made as in ,no4 #c and a mud drum added to the rear end of the sections at the point that was lowest and farthest removed from the fire4 ,the gases were made to pass off at one side and did not come into contact with the mud drum4 ,dry steam was obtained through the increase of separating surface and steam space and the added water capacity furnished a storage for heat to tide over irregularities of firing and feeding4 ,by the addition of the drum1 the boiler became a serviceable and practical design1 retaining all of the features of safety4 ,as the drum was removed from the direct action of the fire1 it was not subjected to excessive strain due to unequal expansion1 and its diameter1 if large in comparison with that of the tubes formerly used1 was small when compared with that of cylindrical boilers4 ,difficulties were encountered in this boiler in securing reliable joints between the wrought-iron tubes and the cast-iron headers4 ,illustration3 ,no4 #e ,no4 #e4 ,in this design1 wrought-iron water legs were substituted for the cast-iron headers1 the tubes being expanded into the inside sheets and a large cover placed opposite the front end of the tubes for cleaning4 ,the tubes were staggered one above the other1 an arrangement found to be more efficient in the absorption of heat than where they were placed in vertical rows4 ,in other respects1 the boiler was similar to ,no4 #d1 except that it had lost the important element of safety through the introduction of the very objectionable feature of flat stayed surfaces4 ,the large doors for access to the tubes were also a cause of weakness4 ,an installation of these boilers was made at the plant of the ,calvert ,sugar ,refinery in ,baltimore1 and while they were satisfactory in their operation1 were never duplicated4 ,illustration3 ,no4 #f ,no4 #f4 ,this was a modification of ,no4 #e in which longer tubes were used and over which the gases were caused to make three passes with a view of better economy4 ,in addition1 some of the stayed surfaces were omitted and handholes substituted for the large access doors4 ,a number of boilers of this design were built but their excessive first cost1 the lack of adjustability of the structure under varying temperatures1 and the inconvenience of transportation1 led to ,no4 #g4 ,illustration3 ,no4 #g ,no4 #g4 ,in this boiler1 the headers and water legs were replaced by ,t-heads screwed to the ends of the inclined tubes4 ,the faces of these ,ts were milled and the tubes placed one above the other with the milled faces metal to metal4 ,long bolts passed through each vertical section of the ,t-heads and through connecting boxes on the heads of the drums holding the whole together4 ,a large number of boilers of this design were built and many were in successful operation for over twenty years4 ,in most instances1 however1 they were altered to later types4 ,illustration3 ,no4 #h ,illustration3 ,no4 #i ,nos4 #h and #i4 ,these boilers were known as the ,griffith ,wundrum type1 the concern which built them being later merged in ,the ,babcock ,wilcox ,co4 ,experiments were made with this design with four passages of the gases across the tubes and the downward circulation of the water at the rear of the boiler was carried to the bottom row of tubes4 ,in ,no4 #i an attempt was made to increase the safety and reduce the cost by reducing the amount of steam and water capacity4 ,a drum at right angles to the line of tubes was used but as there was no provision made to secure dry steam1 the results were not satisfactory4 ,the next move in the direction of safety was the employment of several drums of small diameter instead of a single drum4 ,illustration3 ,no4 #aj ,this is shown in ,no4 #aj4 ,a nest of small horizontal drums1 #ae inches in diameter1 was used in place of the single drum of larger diameter4 ,a set of circulation tubes was placed at an intermediate angle between the main bank of heating tubes and the horizontal drums forming the steam reservoir4 ,these circulators were to return to the rear end of the circulating tubes the water carried up by the circulation1 and in this way were to allow only steam to be delivered to the small drums above4 ,there was no improvement in the action of this boiler over that of ,no4 #i4 ,the four passages of the gas over the tubes tried in ,nos4 #h1 #i and #aj were not found to add to the economy of the boiler4 ,illustration3 ,no4 #aa ,no4 #aa4 ,a trial was next made of a box coil system1 in which the water was made to transverse the furnace several times before being delivered to the drum above4 ,the tendency here1 as in all similar boilers1 was to form steam in the middle of the coil and blow the water from each end1 leaving the tubes practically dry until the steam found an outlet and the water returned4 ,this boiler had1 in addition to a defective circulation1 a decidedly geyser-like action and produced wet steam4 ,illustration3 ,no4 #ab ,all of the types mentioned1 with the exception of ,nos4 #e and #f1 had between their several parts a large number of bolted joints which were subjected to the action of the fire4 ,when these boilers were placed in operation it was demonstrated that as soon as any scale formed on the heating surfaces1 leaks were caused due to unequal expansion4 ,no4 #ab4 ,with this boiler1 an attempt was made to remove the joints from the fire and to increase the heating surface in a given space4 ,water tubes were expanded into both sides of wrought-iron boxes1 openings being made for the admission of water and the exit of steam4 ,fire tubes were placed inside the water tubes to increase the heating surface4 ,this design was abandoned because of the rapid stopping up of the tubes by scale and the impossibility of cleaning them4 ,illustration3 ,no4 #ac ,no4 #ac4 ,vertical straight line headers of cast iron1 each containing two rows of tubes1 were bolted to a connection leading to the steam and water drum above4 ,illustration3 ,no4 #ad ,no4 #ad4 ,a wrought-iron box was substituted for the double cast-iron headers4 ,in this design1 stays were necessary and were found1 as always1 to be an element to be avoided wherever possible4 ,the boiler was an improvement on ,no4 #f1 however4 ,a slanting bridge wall was introduced underneath the drum to throw a larger portion of its heating surface into the combustion chamber under the bank of tubes4 ,this bridge wall was found to be difficult to keep in repair and was of no particular benefit4 ,illustration3 ,no4 #ae ,no4 #ae4 ,each row of tubes was expanded at each end into a continuous header1 cast of car wheel metal4 ,the headers had a sinuous form so that they would lie close together and admit of a staggered position of the tubes when assembled4 ,while other designs of header form were tried later1 experience with ,nos4 #ad and #ae showed that the style here adopted was the best for all purposes and it has not been changed materially since4 ,the drum in this design was supported by girders resting on the brickwork4 ,bolted joints were discarded1 with the exception of those connecting the headers to the front and rear ends of the drums and the bottom of the rear headers to the mud drum4 ,even such joints1 however1 were found objectionable and were superseded in subsequent construction by short lengths of tubes expanded into bored holes4 ,illustration3 ,no4 #af ,no4 #af4 ,in this design1 headers were tried which were made in the form of triangular boxes1 in each of which there were three tubes expanded4 ,these boxes were alternately reversed and connected by short lengths of expanded tubes1 being connected to the drum by tubes bent in a manner to allow them to enter the shell normally4 ,the joints between headers introduced an element of weakness and the connections to the drum were insufficient to give adequate circulation4 ,illustration3 ,no4 #ag ,no4 #ag4 ,straight horizontal headers were next tried1 alternately shifted right and left to allow a staggering of tubes4 ,these headers were connected to each other and to the drums by expanded nipples4 ,the objections to this boiler were almost the same as those to ,no4 #af4 ,illustration3 ,no4 #ah ,illustration3 ,no4 #ai ,nos4 #ah and #ai4 ,these boilers were designed primarily for fire protection purposes1 the requirements demanding a small1 compact boiler with ability to raise steam quickly4 ,these both served the purpose admirably but1 as in ,no4 #i1 the only provision made for the securing of dry steam was the use of the steam dome1 shown in the illustration4 ,this dome was found inadequate and has since been abandoned in nearly all forms of boiler construction4 ,no other remedy being suggested at the time1 these boilers were not considered as desirable for general use as ,nos4 #ba and #bb4 ,in ,europe1 however1 where small size units were more in demand1 ,no4 #ah was modified somewhat and used largely with excellent results4 ,these experiments1 as they may now be called1 although many boilers of some of the designs were built1 clearly demonstrated that the best construction and efficiency required adherence to the following elements of design3 #ast4 ,sinuous headers for each vertical row of tubes4 #bnd4 ,a separate and independent connection with the drum1 both front and rear1 for each vertical row of tubes4 ,illustration3 ,no4 #bj;,a ,illustration3 ,no4 #bj;,b #crd4 ,all joints between parts of the boiler proper to be made without bolts or screw plates4 #dth4 ,no surfaces to be used which necessitate the use of stays4 #eth4 ,the boiler supported independently of the brickwork so as to allow freedom for expansion and contraction as it is heated or cooled4 #fth4 ,ample diameter of steam and water drums1 these not to be less than #cj inches except for small size units4 #gth4 ,every part accessible for cleaning and repairs4 ,with these points having been determined1 ,no4 #bj was designed4 ,this boiler had all the desirable features just enumerated1 together with a number of improvements as to detail of construction4 ,the general form of ,no4 #ae was adhered to but the bolted connections between sections and drum and sections and mud drum were discarded in favor of connections made by short lengths of boiler tubes expanded into the adjacent parts4 ,this boiler was suspended from girders1 like ,no4 #ae1 but these in turn were carried on vertical supports1 leaving the pressure parts entirely free from the brickwork1 the mutually deteriorating strains present where one was supported by the other being in this way overcome4 ,hundreds of thousands of horse power of this design were built1 giving great satisfaction4 ,the boiler was known as the ,c4 ,i4 ,f4 7cast-iron front7 style1 an ornamental cast-iron front having been usually furnished4 ,illustration3 ,no4 #ba ,the next step1 and the one which connects the boilers as described above to the boiler as it is built to-day1 was the design illustrated in ,no4 #ba4 ,these boilers were known as the ,w4 ,i4 ,f4 style1 the fronts furnished as part of the equipment being constructed largely of wrought iron4 ,the cast-iron drumheads used in ,no4 #bj were replaced by wrought-steel flanged and bumped heads4 ,the drums were made longer and the sections connected to wrought-steel cross boxes riveted to the bottom of the drums4 ,the boilers were supported by girders and columns as in ,no4 #bj4 ,illustration3 ,no4 #bb ,no4 #bb4 ,this boiler1 which is designated as the ,vertical ,header type1 has the same general features of construction as ,no4 #ba1 except that the tube sheet side of the headers is stepped to allow the headers to be placed vertically and at right angles to the drum and still maintain the tubes at the angle used in ,nos4 #bj and #ba4 ,illustration3 ,no4 #bc ,no4 #bc1 or the cross drum design of boiler1 is a development of the ,babcock ,wilcox marine boiler1 in which the cross drum is used exclusively4 ,the experience of the ,glasgow ,works of ,the ,babcock ,wilcox1 ,ltd41 with ,no4 #ah proved that proper attention to details of construction would make it a most desirable form of boiler where headroom was limited4 ,a large number of this design have been successfully installed and are giving satisfactory results under widely varying conditions4 ,the cross drum boiler is also built in a vertical header design4 ,boilers ,nos4 #ba1 #bb and #bc1 with a few modifications1 are now the standard forms4 ,these designs are illustrated1 as they are constructed to-day1 on pages #dh1 #eb1 #ed1 #eh and #fj4 ,the last step in the development of the water-tube boiler1 beyond which it seems almost impossible for science and skill to advance1 consists in the making of all pressure parts of the boiler of wrought steel1 including sinuous headers1 cross boxes1 nozzles1 and the like4 ,this construction was the result of the demands of certain ,continental laws that are coming into general vogue in this country4 ,the ,babcock ,wilcox ,co4 have at the present time a plant producing steel forgings that have been pronounced by the ,london ,engineer to be a perfect triumph of the forgers' art4 ,the various designs of this all wrought-steel boiler are fully illustrated in the following pages4 ,illustration3 ,wrought-steel ,vertical ,header ,longitudinal ,drum ,babcock ,wilcox ,boiler1 ,equipped with ,babcock ,wilcox ,superheater and ,babcock ,wilcox ,chain ,grate ,stoker ,,the ,,babcock ,,wilcox ,,boiler ,the following brief description of the ,babcock ,wilcox boiler will clearly indicate the manner in which it fulfills the requirements of the perfect steam boiler already enumerated4 ,the ,babcock ,wilcox boiler is built in two general classes1 the longitudinal drum type and the cross drum type4 ,either of these designs may be constructed with vertical or inclined headers1 and the headers in turn may be of wrought steel or cast iron dependent upon the working pressure for which the boiler is constructed4 ,the headers may be of different lengths1 that is1 may connect different numbers of tubes1 and it is by a change in the number of tubes in height per section and the number of sections in width that the size of the boiler is varied4 ,the longitudinal drum boiler is the generally accepted standard of ,babcock ,wilcox construction4 ,the cross drum boiler1 though originally designed to meet certain conditions of headroom1 has become popular for numerous classes of work where low headroom is not a requirement which must be met4 ,,longitudinal ,,drum ,,construction--,the heating surface of this type of boiler is made up of a drum or drums1 depending upon the width of the boiler extending longitudinally over the other pressure parts4 ,to the drum or drums there are connected through cross boxes at either end the sections1 which are made up of headers and tubes4 ,at the lower end of the sections there is a mud drum extending entirely across the setting and connected to all sections4 ,the connections between all parts are by short lengths of tubes expanded into bored seats4 ,illustration3 ,forged-steel ,drumhead with ,manhole ,plate in ,position ,the drums are of three sheets1 of such thickness as to give the required factor of safety under the maximum pressure for which the boiler is constructed4 ,the circular seams are ordinarily single lap riveted though these may be double lap riveted to meet certain requirements of pressure or of specifications4 ,the longitudinal seams are properly proportioned butt and strap or lap riveted joints dependent upon the pressure for which the boilers are built4 ,where butt strap joints are used the straps are bent to the proper radius in an hydraulic press4 ,the courses are built independently to template and are assembled by an hydraulic forcing press4 ,all riveted holes are punched one-quarter inch smaller than the size of rivets as driven and are reamed to full size after the plates are assembled4 ,all rivets are driven by hydraulic pressure and held until black4 ,illustration3 ,forged-steel ,drumhead ,interior ,the drumheads are hydraulic forged at a single heat1 the manhole opening and stiffening ring being forged in position4 ,flat raised seats for water column and feed connections are formed in the forging4 ,all heads are provided with manholes1 the edges of which are turned true4 ,the manhole plates are of forged steel and turned to fit manhole opening4 ,these plates are held in position by forged-steel guards and bolts4 ,the drum nozzles are of forged steel1 faced1 and fitted with taper thread stud bolts4 ,illustration3 ,forged-steel ,drum ,nozzle ,cross boxes by means of which the sections are attached to the drums1 are of forged steel1 made from a single sheet4 ,where two or more drums are used in one boiler they are connected by a cross pipe having a flanged outlet for the steam connection4 ,illustration3 ,forged-steel ,cross ,box ,the sections are built of #d-;inch hot finished seamless open-hearth steel tubes of ,no4 #aj ,b4 ,w4 ,g4 where the boilers are built for working pressures up to #baj pounds4 ,where the working pressure is to be above this and below #bfj pounds1 ,no4 #i ,b4 ,w4 ,g4 tubes are supplied4 ,illustration3 ,inside ,handhole ,fittings ,wrought-steel ,vertical ,header ,the tubes are expanded into headers of serpentine or sinuous form1 which dispose the tubes in a staggered position when assembled as a complete boiler4 ,these headers are of wrought steel or of cast iron1 the latter being ordinarily supplied where the working pressure is not to exceed #afj pounds4 ,the headers may be either vertical or inclined as shown in the various illustrations of assembled boilers4 ,illustration3 ,wrought-steel ,vertical ,header ,opposite each tube end in the headers there is placed a handhole of sufficient size to permit the cleaning1 removal or renewal of a tube4 ,these openings in the wrought steel vertical headers are elliptical in shape1 machine faced1 and milled to a true plane back from the edge a sufficient distance to make a seat4 ,the openings are closed by inside fitting forged plates1 shouldered to center in the opening1 their flanged seats milled to a true plane4 ,these plates are held in position by studs and forged-steel binders and nuts4 ,the joints between plates and headers are made with a thin gasket4 ,illustration3 ,inside ,handhole ,fitting ,wrought-steel ,inclined ,header ,in the wrought-steel inclined headers the handhole openings are either circular or elliptical1 the former being ordinarily supplied4 ,the circular openings have a raised seat milled to a true plane4 ,the openings are closed on the outside by forged-steel caps1 milled and ground true1 held in position by forged-steel safety clamps and secured by ball-headed bolts to assure correct alignment4 ,with this style of fitting1 joints are made tight1 metal to metal1 without packing of any kind4 ,illustration3 ,wrought-steel ,inclined ,header ,where elliptical handholes are furnished they are faced inside1 closed by inside fitting forged-steel plates1 held to their seats by studs and secured by forged-steel binders and nuts4 ,the joints between plates and header are made with a thin gasket4 ,illustration3 ,cast-iron ,vertical ,header ,the vertical cast-iron headers have elliptical handholes with raised seats milled to a true plane4 ,these are closed on the outside by cast-iron caps milled true1 held in position by forged-steel safety clamps1 which close the openings from the inside and which are secured by ball-headed bolts to assure proper alignment4 ,all joints are made tight1 metal to metal1 without packing of any kind4 ,the mud drum to which the sections are attached at the lower end of the rear headers1 is a forged-steel box #g inches square1 and of such length as to be connected to all headers by means of wrought nipples expanded into counterbored seats4 ,the mud drum is furnished with handholes for cleaning1 these being closed from the inside by forged-steel plates with studs1 and secured on a faced seat in the mud drum by forged-steel binders and nuts4 ,the joints between the plates and the drum are made with thin gaskets4 ,the mud drum is tapped for blow-off connection4 ,all connections between drums and sections and between sections and mud drum are of hot finished seamless open-hearth steel tubes of ,no4 #i ,b4 ,w4 ,g4 ,boilers of the longitudinal drum type are suspended front and rear from wrought-steel supporting frames entirely independent of the brickwork4 ,this allows for expansion and contraction of the pressure parts without straining either the boiler or the brickwork1 and also allows of brickwork repair or renewal without in any way disturbing the boiler or its connections4 ,illustration3 ,babcock ,wilcox ,wrought-steel ,vertical ,header ,cross ,drum ,boiler ,,cross ,,drum ,,construction--,the cross drum type of boilers differs from the longitudinal only in drum construction and method of support4 ,the drum in this type is placed transversely across the rear of the boiler and is connected to the sections by means of circulating tubes expanded into bored seats4 ,the drums for all pressures are of two sheets of sufficient thickness to give the required factor of safety4 ,the longitudinal seams are double riveted butt strapped1 the straps being bent to the proper radius in an hydraulic press4 ,the circulating tubes are expanded into the drums at the seams1 the butt straps serving as tube seats4 ,the drumheads1 drum fittings and features of riveting are the same in the cross drum as in the longitudinal types4 ,the sections and mud drum are also the same for the two types4 ,cross drum boilers are supported at the rear on the mud drum which rests on cast-iron foundation plates4 ,they are suspended at the front from a wrought-iron supporting frame1 each section being suspended independently from the cross members by hook suspension bolts4 ,this method of support is such as to allow for expansion and contraction without straining either the boiler or the brickwork and permits of repair or renewal of the latter without in any way disturbing the boiler or its connections4 ,the following features of design and of attachments supplied are the same for all types4 ,,fronts--,ornamental fronts are fitted to the front supporting frame4 ,these have large doors for access to the front headers and panels above the fire fronts4 ,the fire fronts where furnished have independent frames for fire doors which are bolted on1 and ashpit doors fitted with blast catches4 ,the lugs on door frames and on doors are cast solid4 ,the faces of doors and of frames are planed and the lugs milled4 ,the doors and frames are placed in their final relative position1 clamped1 and the holes for hinge pins drilled while thus held4 ,a perfect alignment of door and frame is thus assured and the method is representative of the care taken in small details of manufacture4 ,the front as a whole is so arranged that any stoker may be applied with but slight modification wherever boilers are set with sufficient furnace height4 ,illustration3 ,cross ,drum ,boiler ,front ,in the vertical header boilers large wrought-iron doors1 which give access to the rear headers1 are attached to the rear supporting frame4 ,illustration3 ,wrought-steel ,inclined ,header ,longitudinal ,drum ,babcock ,wilcox ,boiler1 ,equipped with ,babcock ,wilcox ,superheater ,illustration3 ,automatic ,drumhead ,stop and ,check ,valve ,,fittings--,each boiler is provided with the following fittings as part of the standard equipment3 ,blow-off connections and valves attached to the mud drum4 ,safety valves placed on nozzles on the steam drums4 ,a water column connected to the front of the drum4 ,a steam gauge attached to the boiler front4 ,feed water connection and valves4 ,a flanged stop and check valve of heavy pattern is attached directly to each drumhead1 closing automatically in case of a rupture in the feed line4 ,all valves and fittings are substantially built and are of designs which by their successful service for many years have become standard with ,the ,babcock ,wilcox ,co4 ,the fixtures that are supplied with the boilers consist of3 ,dead plates and supports1 the plates arranged for a fire brick lining4 ,a full set of grate bars and bearers1 the latter fitted with expansion sockets for side walls4 ,flame bridge plates with necessary fastenings1 and special fire brick for lining same4 ,bridge wall girder for hanging bridge wall with expansion sockets for side walls4 ,a full set of access and cleaning doors through which all portions of the pressure parts may be reached4 ,a swing damper and frame with damper operating rig4 ,there are also supplied with each boiler a wrench for handhole nuts1 a water-driven turbine tube cleaner1 a set of fire tools and a metal steam hose and cleaning pipe equipped with a special nozzle for blowing dust and soot from the tubes4 ,aside from the details of design and construction as covered in the foregoing description1 a study of the illustrations will make clear the features of the boiler as a whole which have led to its success4 ,the method of supporting the boiler has been described4 ,this allows it to be hung at any height that may be necessary to properly handle the fuel to be burned or to accommodate the stoker to be installed4 ,the height of the nest of tubes which forms the roof of the furnace is thus the controlling feature in determining the furnace height1 or the distance from the front headers to the floor line4 ,the sides and front of the furnace are formed by the side and front boiler walls4 ,the rear wall of the furnace consists of a bridge wall built from the bottom of the ashpit to the lower row of tubes4 ,the location of this wall may be adjusted within limits to give the depth of furnace demanded by the fuel used4 ,ordinarily the bridge wall is the determining feature in the locating of the front baffle4 ,where a great depth of furnace is necessary1 in which case1 if the front baffle were placed at the bridge wall the front pass of the boiler would be relatively too long1 a patented construction is used which maintains the baffle in what may be considered its normal position1 and a connection made between the baffle and the bridge wall by means of a tile roof4 ,such furnace construction is known as a ,webster furnace4 ,illustration3 ,longitudinal ,drum ,boiler--,front ,view ,a consideration of this furnace will clearly indicate its adaptability1 by reason of its flexibility1 for any fuel and any design of stoker4 ,the boiler lends itself readily to installation with an extension or ,dutch oven furnace if this be demanded by the fuel to be used1 and in general it may be stated that a satisfactory furnace arrangement may be made in connection with a ,babcock ,wilcox boiler for burning any fuel1 solid1 liquid or gaseous4 ,the gases of combustion evolved in the furnace above described are led over the heating surfaces by two baffles4 ,these are formed of cast-iron baffle plates lined with special fire brick and held in position by tube clamps4 ,the front baffle leads the gases through the forward portion of the tubes to a chamber beneath the drum or drums4 ,it is in this chamber that a superheater is installed where such an apparatus is desired4 ,the gases make a turn over the front baffle1 are led downward through the central portion of the tubes1 called the second pass1 by means of a hanging bridge wall of brick and the second baffle1 around which they make a second turn upward1 pass through the rear portion of the tubes and are led to the stack or flue through a damper box in the rear wall1 or around the drums to a damper box placed overhead4 ,the space beneath the tubes between the bridge wall and the rear boiler wall forms a pocket into which much of the soot from the gases in their downward passage through the second pass will be deposited and from which it may be readily cleaned through doors furnished for the purpose4 ,the gas passages are ample and are so proportioned that the resistance offered to the gases is only such as will assure the proper abstraction of heat from the gases without causing undue friction1 requiring excessive draft4 ,illustration3 ,partial ,vertical ,section ,showing ,method of ,introducing ,feed ,water ,the method in which the feed water is introduced through the front drumhead of the boiler is clearly seen by reference to the illustration4 ,from this point of introduction the water passes to the rear of the drum1 downward through the rear circulating tubes to the sections1 upward through the tubes of the sections to the front headers and through these headers and front circulating tubes again to the drum where such water as has not been formed into steam retraces its course4 ,the steam formed in the passage through the tubes is liberated as the water reaches the front of the drum4 ,the steam so formed is stored in the steam space above the water line1 from which it is drawn through a so-called dry pipe4 ,the dry pipe in the ,babcock ,wilcox boiler is misnamed1 as in reality it fulfills none of the functions ordinarily attributed to such a device4 ,this function is usually to restrict the flow of steam from a boiler with a view to avoid priming4 ,in the ,babcock ,wilcox boiler its function is simply that of a collecting pipe1 and as the aggregate area of the holes in it is greatly in excess of the area of the steam outlet from the drum1 it is plain that there can be no restriction through this collecting pipe4 ,it extends nearly the length of the drum1 and draws steam evenly from the whole length of the steam space4 ,illustration3 ,cast-iron ,vertical ,header ,longitudinal ,drum ,babcock ,wilcox ,boiler ,illustration3 ,closed ,open ,patented ,side ,dusting ,doors ,the large tube doors through which access is had to the front headers and the doors giving such access to the rear headers in boilers of the vertical header type have already been described and are shown clearly by the illustrations on pages #ef and #gd4 ,in boilers of the inclined header type1 access to the rear headers is secured through the chamber formed by the headers and the rear boiler wall4 ,large doors in the sides of the setting give full access to all parts for inspection and for removal of accumulations of soot4 ,small dusting doors are supplied for the side walls through which all of the heating surfaces may be cleaned by means of a steam dusting lance4 ,these side dusting doors are a patented feature and the shutters are self closing4 ,in wide boilers additional cleaning doors are supplied at the top of the setting to insure ease in reaching all portions of the heating surface4 ,the drums are accessible for inspection through the manhole openings4 ,the removal of the handhole plates makes possible the inspection of each tube for its full length and gives the assurance that no defect can exist that cannot be actually seen4 ,this is particularly advantageous when inspecting for the presence of scale4 ,the materials entering into the construction of the ,babcock ,wilcox boiler are the best obtainable for the special purpose for which they are used and are subjected to rigid inspection and tests4 ,the boilers are manufactured by means of the most modern shop equipment and appliances in the hands of an old and well-tried organization of skilled mechanics under the supervision of experienced engineers4 ,illustration3 ,cast-iron ,vertical ,header ,cross ,drum ,babcock ,wilcox ,boiler ,,advantages ,,of ,,the ,,babcock ,,wilcox ,,boiler ,the advantages of the ,babcock ,wilcox boiler may perhaps be most clearly set forth by a consideration1 #ast1 of water-tube boilers as a class as compared with shell and fire-tube boilers2 and #bnd1 of the ,babcock ,wilcox boiler specifically as compared with other designs of water-tube boilers4 ,,water-,,tube ,,versus ,,fire-,,tube ,,boilers ,safety--,the most important requirement of a steam boiler is that it shall be safe in so far as danger from explosion is concerned4 ,if the energy in a large shell boiler under pressure is considered1 the thought of the destruction possible in the case of an explosion is appalling4 ,the late ,dr4 ,robert ,h4 ,thurston1 ,dean of ,sibley ,college1 ,cornell ,university1 and past president of the ,american ,society of ,mechanical ,engineers1 estimated that there is sufficient energy stored in a plain cylinder boiler under #ajj pounds steam pressure to project it in case of an explosion to a height of over #c miles2 a locomotive boiler at #abe pounds pressure from one-half to one-third of a mile2 and a #fj horse-power return tubular boiler under #ge pounds pressure somewhat over a mile4 ,to quote3 ,a cubic foot of heated water under a pressure of from #fj to #gj pounds per square inch has about the same energy as one pound of gunpowder4 ,from such a consideration1 it may be readily appreciated how the advent of high pressure steam was one of the strongest factors in forcing the adoption of water-tube boilers4 ,a consideration of the thickness of material necessary for cylinders of various diameters under a steam pressure of #bjj pounds and assuming an allowable stress of #ab1jjj pounds per square inch1 will perhaps best illustrate this point4 ,table #a gives such thicknesses for various diameters of cylinders not taking into consideration the weakening effect of any joints which may be necessary4 ,the rapidity with which the plate thickness increases with the diameter is apparent and in practice1 due to the fact that riveted joints must be used1 the thicknesses as given in the table1 with the exception of the first1 must be increased from #cj to #dj per cent4 ,in a water-tube boiler the drums seldom exceed #dh inches in diameter and the thickness of plate required1 therefore1 is never excessive4 ,the thinner metal can be rolled to a more uniform quality1 the seams admit of better proportioning1 and the joints can be more easily and perfectly fitted than is the case where thicker plates are necessary4 ,all of these points contribute toward making the drums of water-tube boilers better able to withstand the stress which they will be called upon to endure4 ,the essential constructive difference between water-tube and fire-tube boilers lies in the fact that the former is composed of parts of relatively small diameter as against the large diameters necessary in the latter4 ,the factor of safety of the boiler parts which come in contact with the most intense heat in water-tube boilers can be made much higher than would be practicable in a shell boiler4 ,under the assumptions considered above in connection with the thickness of plates required1 a number #aj gauge tube 7#j4acd inch71 which is standard in ,babcock ,wilcox boilers for pressures up to #baj pounds under the same allowable stress as was used in computing ,table #a1 the safe working pressure for the tubes is #hgj pounds per square inch1 indicating the very large margin of safety of such tubes as compared with that possible with the shell of a boiler4 ,,table #a ,,plate ,,thickness ,,required ,,for ,,various ,,cylinder ,,diameters ,,allowable ,,stress1 #abjjj ,,pounds ,,per ,,square ,,inch1 #bjj ,,pounds ,,gauge ,,pressure1 ,,no ,,joints -------------------- ,diameter ,thickness ,inches ,inches -------------------- #d #j4jcc #cf #j4cjj #dh #j4djj #fj #j4ejj #gb #j4fjj #ajh #j4ijj #abj #a4jjj #add #a4bjj -------------------- ,a further advantage in the water-tube boiler as a class is the elimination of all compressive stresses4 ,cylinders subjected to external pressures1 such as fire tubes or the internally fired furnaces of certain types of boilers1 will collapse under a pressure much lower than that which they could withstand if it were applied internally4 ,this is due to the fact that if there exists any initial distortion from its true shape1 the external pressure will tend to increase such distortion and collapse the cylinder1 while an internal pressure tends to restore the cylinder to its original shape4 ,stresses due to unequal expansion have been a fruitful source of trouble in fire-tube boilers4 ,in boilers of the shell type1 the riveted joints of the shell1 with their consequent double thickness of metal exposed to the fire1 gives rise to serious difficulties4 ,upon these points are concentrated all strains of unequal expansion1 giving rise to frequent leaks and oftentimes to actual ruptures4 ,moreover1 in the case of such rupture1 the whole body of contained water is liberated instantaneously and a disastrous and usually fatal explosion results4 ,further1 unequal strains result in shell or fire-tube boilers due to the difference in temperature of the various parts4 ,this difference in temperature results from the lack of positive well defined circulation4 ,while such a circulation does not necessarily accompany all water-tube designs1 in general1 the circulation in water-tube boilers is much more defined than in fire-tube or shell boilers4 ,a positive and efficient circulation assures that all portions of the pressure parts will be at approximately the same temperature and in this way strains resulting from unequal temperatures are obviated4 ,if a shell or fire-tubular boiler explodes1 the apparatus as a whole is destroyed4 ,in the case of water-tube boilers1 the drums are ordinarily so located that they are protected from intense heat and any rupture is usually in the case of a tube4 ,tube failures1 resulting from blisters or burning1 are not serious in their nature4 ,where a tube ruptures because of a flaw in the metal1 the result may be more severe1 but there cannot be the disastrous explosion such as would occur in the case of the explosion of a shell boiler4 ,to quote ,dr4 ,thurston1 relative to the greater safety of the water-tube boiler3 ,the stored available energy is usually less than that of any of the other stationary boilers and not very far from the amount stored1 pound for pound1 in the plain tubular boiler4 ,it is evident that their admitted safety from destructive explosion does not come from this relation1 however1 but from the division of the contents into small portions and especially from those details of construction which make it tolerably certain that any rupture shall be local4 ,a violent explosion can only come from the general disruption of a boiler and the liberation at once of large masses of steam and water4 ,economy--,the requirement probably next in importance to safety in a steam boiler is economy in the use of fuel4 ,to fulfill such a requirement1 the three items1 of proper grate for the class of fuel to be burned1 a combustion chamber permitting complete combustion of gases before their escape to the stack1 and the heating surface of such a character and arrangement that the maximum amount of available heat may be extracted1 must be co-ordinated4 ,fire-tube boilers from the nature of their design do not permit the variety of combinations of grate surface1 heating surface1 and combustion space possible in practically any water-tube boiler4 ,in securing the best results in fuel economy1 the draft area in a boiler is an important consideration4 ,in fire-tube boilers this area is limited to the cross sectional area of the fire tubes1 a condition further aggravated in a horizontal boiler by the tendency of the hot gases to pass through the upper rows of tubes instead of through all of the tubes alike4 ,in water-tube boilers the draft area is that of the space outside of the tubes and is hence much greater than the cross sectional area of the tubes4 ,capacity--,due to the generally more efficient circulation found in water-tube than in fire-tube boilers1 rates of evaporation are possible with water-tube boilers that cannot be approached where fire-tube boilers are employed4 ,quick ,steaming--,another important result of the better circulation ordinarily found in water-tube boilers is in their ability to raise steam rapidly in starting and to meet the sudden demands that may be thrown on them4 ,in a properly designed water-tube boiler steam may be raised from a cold boiler to #bjj pounds pressure in less than one-half hour4 ,for the sake of comparison with the figure above1 it may be stated that in the ,u4 ,s4 ,government ,service the shortest time allowed for getting up steam in ,scotch marine boilers is #f hours and the time ordinarily allowed is #ab hours4 ,in large double-ended ,scotch boilers1 such as are generally used in ,trans-,atlantic service1 the fires are usually started #bd hours before the time set for getting under way4 ,this length of time is necessary for such boilers in order to eliminate as far as possible excessive strains resulting from the sudden application of heat to the surfaces4 ,accessibility--,in the ,requirements of a ,perfect ,steam ,boiler1 as stated by ,mr4 ,babcock1 he demonstrates the necessity for complete accessibility to all portions of the boiler for cleaning1 inspection and repair4 ,cleaning--,when the great difference is realized in performance1 both as to economy and capacity of a clean boiler and one in which the heating surfaces have been allowed to become fouled1 it may be appreciated that the ability to keep heating surfaces clean internally and externally is a factor of the highest importance4 ,such results can be accomplished only by the use of a design in boiler construction which gives complete accessibility to all portions4 ,in fire-tube boilers the tubes are frequently nested together with a space between them often less than #a inches and1 as a consequence1 nearly the entire tube surface is inaccessible4 ,when scale forms upon such tubes it is impossible to remove it completely from the inside of the boiler and if it is removed by a turbine hammer1 there is no way of knowing how thorough a job has been done4 ,with the formation of such scale there is danger through overheating and frequent tube renewals are necessary4 ,illustration3 ,portion of #bi1jjj ,horse-power ,installation of ,babcock ,wilcox ,boilers in the ,l ,street ,station of the ,edison ,electric ,illuminating ,co4 of ,boston1 ,mass4 ,this ,company ,operates in its ,various ,stations a ,total of #ci1jjj ,horse ,power of ,babcock ,wilcox ,boilers ,in ,scotch marine boilers1 even with the engines operating condensing1 complete tube renewals at intervals of six or seven years are required1 while large replacements are often necessary in less than one year4 ,in return tubular boilers operated with bad feed water1 complete tube renewals annually are not uncommon4 ,in this type of boiler much sediment falls on the bottom sheets where the intense heat to which they are subjected bakes it to such an excessive hardness that the only method of removing it is to chisel it out4 ,this can be done only by omitting tubes enough to leave a space into which a man can crawl and the discomforts under which he must work are apparent4 ,unless such a deposit is removed1 a burned and buckled plate will invariably result1 and if neglected too long an explosion will follow4 ,in vertical fire-tube boilers using a water leg construction1 a deposit of mud in such legs is an active agent in causing corrosion and the difficulty of removing such deposit through handholes is well known4 ,a complete removal is practically impossible and as a last resort to obviate corrosion in certain designs1 the bottom of the water legs in some cases have been made of copper4 ,a thick layer of mud and scale is also liable to accumulate on the crown sheet of such boilers and may cause the sheet to crack and lead to an explosion4 ,the soot and fine coal swept along with the gases by the draft will settle in fire tubes and unless removed promptly1 must be cut out with a special form of scraper4 ,it is not unusual where soft coal is used to find tubes half filled with soot1 which renders useless a large portion of the heating surface and so restricts the draft as to make it difficult to burn sufficient coal to develop the required power from such heating surface as is not covered by soot4 ,water-tube boilers in general are from the nature of their design more readily accessible for cleaning than are fire-tube boilers4 ,inspection--,the objections given above in the consideration of the inability to properly clean fire-tube boilers hold as well for the inspection of such boilers4 ,repairs--,the lack of accessibility in fire-tube boilers further leads to difficulties where repairs are required4 ,in fire-tube boilers tube renewals are a serious undertaking4 ,the accumulation of hard deposit on the exterior of the surfaces so enlarges the tubes that it is oftentimes difficult1 if not impossible1 to draw them through the tube sheets and it is usually necessary to cut out such tubes as will allow access to the one which has failed and remove them through the manhole4 ,when a tube sheet blisters1 the defective part must be cut out by hand-tapped holes drilled by ratchets and as it is frequently impossible to get space in which to drive rivets1 a soft patch is necessary4 ,this is but a makeshift at best and usually results in either a reduction of the safe working pressure or in the necessity for a new plate4 ,if the latter course is followed1 the old plate must be cut out1 a new one scribed to place to locate rivet holes and in order to obtain room for driving rivets1 the boiler will have to be re-tubed4 ,the setting must1 of course1 be at least partially torn out and replaced4 ,in case of repairs1 of such nature in fire-tube boilers1 the working pressure of such repaired boilers will frequently be lowered by the insurance companies when the boiler is again placed in service4 ,in the case of a rupture in a water-tube boiler1 the loss will ordinarily be limited to one or two tubes which can be readily replaced4 ,the fire-tube boiler will be so completely demolished that the question of repairs will be shifted from the boiler to the surrounding property1 the damage to which will usually exceed many times the cost of a boiler of a type which would have eliminated the possibility of a disastrous explosion4 ,in considering the proper repair cost of the two types of boilers1 the fact should not be overlooked that it is poor economy to invest large sums in equipment that1 through a possible accident to the boiler may be wholly destroyed or so damaged that the cost of repairs1 together with the loss of time while such repairs are being made1 would purchase boilers of absolute safety and leave a large margin beside4 ,the possibility of loss of human life should also be considered1 though this may seem a far cry from the question of repair costs4 ,space ,occupied--,the space required for the boilers in a plant often exceeds the requirements for the remainder of the plant equipment4 ,any saving of space in a boiler room will be a large factor in reducing the cost of real estate and of the building4 ,even when the boiler plant is comparatively small1 the saving in space frequently will amount to a considerable percentage of the cost of the boilers4 ,table #b shows the difference in floor space occupied by fire-tube boilers and ,babcock ,wilcox boilers of the same capacity1 the latter being taken as representing the water-tube class4 ,this saving in space will increase with the size of the plant for the reason that large size boiler units while common in water-tube practice are impracticable in fire-tube practice4 ,,table #b ,,comparative ,,approximate ,,floor ,,space ,,occupied ,,by ,,babcock ,,wilcox ,,and ,h4 ,r4 ,t4 ,,boilers ---------------------------------------- --- ,size of unit,babcock ,wilcox ,h4 ,r4 ,t4 ,horse ,power ,feet and ,inches ,feet and ,inches ---------------------------------------- --- #ajj #g #c #ai #i #aj #j #bj #j #aej #g #aj #ai #i #aj #j #bb #f #bjj #i #j #ai #i #aa #f #bc #aj #bej #i #j #ai #i #aa #f #bc #aj #cjj #aj #b #ai #i #ab #j #be #j ---------------------------------------- --- ,,babcock ,,wilcox ,,boilers ,,as ,,compared ,,with ,,other ,,water-,,tube ,,designs ,it must be borne in mind that the simple fact that a boiler is of the water-tube design does not as a necessity indicate that it is a good or safe boiler4 ,safety--,many of the water-tube boilers on the market are as lacking as are fire-tube boilers in the positive circulation which1 as has been demonstrated by ,mr4 ,babcock's lecture1 is so necessary in the requirements of the perfect steam boiler4 ,in boilers using water-leg construction1 there is danger of defective circulation1 leaks are common1 and unsuspected corrosion may be going on in portions of the boiler that cannot be inspected4 ,stresses due to unequal expansion of the metal cannot be well avoided but they may be minimized by maintaining at the same temperature all pressure parts of the boiler4 ,the result is to be secured only by means of a well defined circulation4 ,the main feature to which the ,babcock ,wilcox boiler owes its safety is the construction made possible by the use of headers1 by which the water in each vertical row of tubes is separated from that in the adjacent rows4 ,this construction results in the very efficient circulation produced through the breaking up of the steam and water in the front headers1 the effect of these headers in producing such a positive circulation having been clearly demonstrated in ,mr4 ,babcock's lecture4 ,the use of a number of sections1 thus composed of headers and tubes1 has a distinct advantage over the use of a common chamber at the outlet ends of the tubes4 ,in the former case the circulation of water in one vertical row of tubes cannot interfere with that in the other rows1 while in the latter construction there will be downward as well as upward currents and such downward currents tend to neutralize any good effect there might be through the diminution of the density of the water column by the steam4 ,further1 the circulation results directly from the design of the boiler and requires no assistance from retarders1 check valves and the like1 within the boiler4 ,all such mechanical devices in the interior of a boiler serve only to complicate the design and should not be used4 ,this positive and efficient circulation assures that all portions of the pressure parts of the ,babcock ,wilcox boiler will be at approximately the same temperature and in this way strains resulting from unequal temperatures are obviated4 ,where the water throughout the boiler is at the temperature of the steam contained1 a condition to be secured only by proper circulation1 danger from internal pitting is minimized1 or at least limited only to effects of the water fed the boiler4 ,where the water in any portion of the boiler is lower than the temperature of the steam corresponding to the pressure carried1 whether the fact that such lower temperatures exist as a result of lack of circulation1 or because of intentional design1 internal pitting or corrosion will almost invariably result4 ,dr4 ,thurston has already been quoted to the effect that the admitted safety of a water-tube boiler is the result of the division of its contents into small portions4 ,in boilers using a water-leg construction1 while the danger from explosion will be largely limited to the tubes1 there is the danger1 however1 that such legs may explode due to the deterioration of their stays1 and such an explosion might be almost as disastrous as that of a shell boiler4 ,the headers in a ,babcock ,wilcox boiler are practically free from any danger of explosion4 ,were such an explosion to occur1 it would still be localized to a much larger extent than in the case of a water-leg boiler and the header construction thus almost absolutely localizes any danger from such a cause4 ,staybolts are admittedly an undesirable element of construction in any boiler4 ,they are wholly objectionable and the only reason for the presence of staybolts in a boiler is to enable a cheaper form of construction to be used than if they were eliminated4 ,in boilers utilizing in their design flat-stayed surfaces1 or staybolt construction under pressure1 corrosion and wear and tear in service tends to weaken some single part subject to continual strain1 the result being an increased strain on other parts greatly in excess of that for which an allowance can be made by any reasonable factor of safety4 ,where the construction is such that the weakening of a single part will produce a marked decrease in the safety and reliability of the whole1 it follows of necessity1 that there will be a corresponding decrease in the working pressure which may be safely carried4 ,in water-leg boilers1 the use of such flat-stayed surfaces under pressure presents difficulties that are practically unsurmountable4 ,such surfaces exposed to the heat of the fire are subject to unequal expansion1 distortion1 leakage and corrosion1 or in general1 to many of the objections that have already been advanced against the fire-tube boilers in the consideration of water-tube boilers as a class in comparison with fire-tube boilers4 ,illustration3 ,mc,alpin ,hotel1 ,new ,york ,city1 ,operating #bcfj ,horse ,power of ,babcock ,wilcox ,boilers ,aside from the difficulties that may arise in actual service due to the failure of staybolts1 or in general1 due to the use of flat-stayed surfaces1 constructional features are encountered in the actual manufacture of such boilers that make it difficult if not impossible to produce a first-class mechanical job4 ,it is practically impossible in the building of such a boiler to so design and place the staybolts that all will be under equal strain4 ,such unequal strains1 resulting from constructional difficulties1 will be greatly multiplied when such a boiler is placed in service4 ,much of the riveting in boilers of this design must of necessity be hand work1 which is never the equal of machine riveting4 ,the use of water-leg construction ordinarily requires the flanging of large plates1 which is difficult1 and because of the number of heats necessary and the continual working of the material1 may lead to the weakening of such plates4 ,in vertical or semi-vertical water-tube boilers utilizing flat-stayed surfaces under pressure1 these surfaces are ordinarily so located as to offer a convenient lodging place for flue dust1 which fuses into a hard mass1 is difficult of removal and under which corrosion may be going on with no possibility of detection4 ,where stayed surfaces or water legs are features in the design of a water-tube boiler1 the factor of safety of such parts must be most carefully considered4 ,in such parts too1 is the determination of the factor most difficult1 and because of the rule-of-thumb determination frequently necessary1 the factor of safety becomes in reality a factor of ignorance4 ,as opposed to such indeterminate factors of safety1 in the ,babcock ,wilcox boiler1 when the factor of safety for the drum or drums has been determined1 and such a factor may be determined accurately1 the factors for all other portions of the pressure parts are greatly in excess of that of the drum4 ,all ,babcock ,wilcox boilers are built with a factor of safety of at least five1 and inasmuch as the factor of the safety of the tubes and headers is greatly in excess of this figure1 it applies specifically to the drum or drums4 ,this factor represents a greater degree of safety than a considerably higher factor applied to a boiler in which the shell or any riveted portion is acted upon directly by the fire1 or the same factor applied to a boiler utilizing flat-stayed surface construction1 where the accurate determination of the limiting factor of safety is difficult1 if not impossible4 ,that the factor of safety of stayed surfaces is questionable may perhaps be best realized from a consideration of the severe requirements as to such factor called for by the rules and regulations of the ,board of ,supervising ,inspectors1 ,u4 ,s4 ,government4 ,in view of the above1 the absence of any stayed surfaces in the ,babcock ,wilcox boiler is obviously a distinguishing advantage where safety is a factor4 ,it is of interest to note1 in the article on the evolution of the ,babcock ,wilcox boiler1 that staybolt construction was used in several designs1 found unsatisfactory and unsafe1 and discarded4 ,another feature in the design of the ,babcock ,wilcox boiler tending toward added safety is its manner of suspension4 ,this has been indicated in the previous chapter and is of such nature that all of the pressure parts are free to expand or contract under variations of temperature without in any way interfering with any part of the boiler setting4 ,the sectional nature of the boiler allows a flexibility under varying temperature changes that practically obviates internal strain4 ,in boilers utilizing water-leg construction1 on the other hand1 the construction is rigid1 giving rise to serious internal strains and the method of support ordinarily made necessary by the boiler design is not only unmechanical but frequently dangerous1 due to the fact that proper provision is not made for expansion and contraction under temperature variations4 ,boilers utilizing water-leg construction are not ordinarily provided with mud drums4 ,this is a serious defect in that it allows impurities and sediment to collect in a portion of the boiler not easily inspected1 and corrosion may result4 ,economy--,that the water-tube boiler as a class lends itself more readily than does the fire-tube boiler to a variation in the relation of grate surface1 heating surface and combustion space has been already pointed out4 ,in economy again1 the construction made possible by the use of headers in ,babcock ,wilcox boilers appears as a distinct advantage4 ,because of this construction1 there is a flexibility possible1 in an unlimited variety of heights and widths that will satisfactorily meet the special requirements of the fuel to be burned in individual cases4 ,an extended experience in the design of furnaces best suited for a wide variety of fuels has made ,the ,babcock ,wilcox ,co4 leaders in the field of economy4 ,furnaces have been built and are in successful operation for burning anthracite and bituminous coals1 lignite1 crude oil1 gas-house tar1 wood1 sawdust and shavings1 bagasse1 tan bark1 natural gas1 blast furnace gas1 by-product coke oven gas and for the utilization of waste heat from commercial processes4 ,the great number of ,babcock ,wilcox boilers now in satisfactory operation under such a wide range of fuel conditions constitutes an unimpeachable testimonial to the ability to meet all of the many conditions of service4 ,the limitations in the draft area of fire-tube boilers as affecting economy have been pointed out4 ,that a greater draft area is possible in water-tube boilers does not of necessity indicate that proper advantage of this fact is taken in all boilers of the water-tube class4 ,in the ,babcock ,wilcox boiler1 the large draft area taken in connection with the effective baffling allows the gases to be brought into intimate contact with all portions of the heating surfaces and renders such surfaces highly efficient4 ,in certain designs of water-tube boilers the baffling is such as to render ineffective certain portions of the heating surface1 due to the tendency of soot and dirt to collect on or behind baffles1 in this way causing the interposition of a layer of non-conducting material between the hot gases and the heating surfaces4 ,in ,babcock ,wilcox boilers the standard baffle arrangement is such as to allow the installation of a superheater without in any way altering the path of the gases from furnace to stack1 or requiring a change in the boiler design4 ,in certain water-tube boilers the baffle arrangement is such that if a superheater is to be installed a complete change in the ordinary baffle design is necessary4 ,frequently to insure sufficiently hot gas striking the heating surfaces1 a portion is by-passed directly from the furnace to the superheater chamber without passing over any of the boiler heating surfaces4 ,any such arrangement will lead to a decrease in economy and the use of boilers requiring it should be avoided4 ,capacity--,babcock ,wilcox boilers are run successfully in every-day practice at higher ratings than any other boilers in practical service4 ,the capacities thus obtainable are due directly to the efficient circulation already pointed out4 ,inasmuch as the construction utilizing headers has a direct bearing in producing such circulation1 it is also connected with the high capacities obtainable with this apparatus4 ,where intelligently handled and kept properly cleaned1 ,babcock ,wilcox boilers are operated in many plants at from #bjj to #bbe per cent of their rated evaporative capacity and it is not unusual for them to be operated at #cjj per cent of such rated capacity during periods of peak load4 ,dry ,steam--,in the list of the requirements of the perfect steam boiler1 the necessity that dry steam be generated has been pointed out4 ,the ,babcock ,wilcox boiler will deliver dry steam under higher capacities and poorer conditions of feed water than any other boiler now manufactured4 ,certain boilers will1 when operated at ordinary ratings1 handle poor feed water and deliver steam in which the moisture content is not objectionable4 ,when these same boilers are driven at high overloads1 there will be a direct tendency to prime and the percentage of moisture in the steam delivered will be high4 ,this tendency is the result of the lack of proper circulation and once more there is seen the advantage of the headers of the ,babcock ,wilcox boiler1 resulting as it does in the securing of a positive circulation4 ,in the design of the ,babcock ,wilcox boiler sufficient space is provided between the steam outlet and the disengaging point to insure the steam passing from the boiler in a dry state without entraining or again picking up any particles of water in its passage even at high rates of evaporation4 ,ample time is given for a complete separation of steam from the water at the disengaging surface before the steam is carried from the boiler4 ,these two features1 which are additional causes for the ability of the ,babcock ,wilcox boiler to deliver dry steam1 result from the proper proportioning of the steam and water space of the boiler4 ,from the history of the development of the boiler1 it is evident that the cubical capacity per horse power of the steam and water space has been adopted after numerous experiments4 ,that the dry pipe serves in no way the generally understood function of such device has been pointed out4 ,as stated1 the function of the dry pipe in a ,babcock ,wilcox boiler is simply that of a collecting pipe and this statement holds true regardless of the rate of operation of the boiler4 ,in certain boilers1 superheating surface is provided to dry the steam1 or to remove the moisture due to priming or foaming4 ,such surface is invariably a source of trouble unless the steam is initially dry and a boiler which will deliver dry steam is obviously to be preferred to one in which surface must be supplied especially for such purpose4 ,where superheaters are installed with ,babcock ,wilcox boilers1 they are in every sense of the word superheaters and not driers1 the steam being delivered to them in a dry state4 ,the question has been raised in connection with the cross drum design of the ,babcock ,wilcox boiler as to its ability to deliver dry steam4 ,experience has shown the absolute lack of basis for any such objection4 ,the ,babcock ,wilcox ,company at its ,bayonne ,works some time ago made a series of experiments to see in what manner the steam generated was separated from the water either in the drum or in its passage to the drum4 ,glass peepholes were installed in each end of a drum in a boiler of the marine design1 at the point midway between that at which the horizontal circulating tubes entered the drum and the drum baffle plate4 ,by holding a light at one of these peepholes the action in the drum was clearly seen through the other4 ,it was found that with the boiler operated under three-quarter inch ashpit pressure1 which1 with the fuel used would be equivalent to approximately #ahe per cent of rating for stationary boiler practice1 that each tube was delivering with great velocity a stream of solid water1 which filled the tube for half its cross sectional area4 ,there was no spray or mist accompanying such delivery1 clearly indicating that the steam had entirely separated from the water in its passage through the horizontal circulating tubes1 which in the boiler in question were but #ej inches long4 ,illustration3 ,northwest ,station of the ,commonwealth ,edison ,co41 ,chicago1 ,ill4 ,this ,installation ,consists of #aa1cfj ,horse ,power of ,babcock ,wilcox ,boilers and ,superheaters1 ,equipped with ,babcock ,wilcox ,chain ,grate ,stokers ,these experiments proved conclusively that the size of the steam drums in the cross drum design has no appreciable effect in determining the amount of liberating surface1 and that sufficient liberating surface is provided in the circulating tubes alone4 ,if further proof of the ability of this design of boiler to deliver dry steam is required1 such proof is perhaps best seen in the continued use of the ,babcock ,wilcox marine boiler1 in which the cross drum is used exclusively1 and with which rates of evaporation are obtained far in excess of those secured in ordinary practice4 ,quick ,steaming--,the advantages of water-tube boilers as a class over fire-tube boilers in ability to raise steam quickly have been indicated4 ,due to the constant and thorough circulation resulting from the sectional nature of the ,babcock ,wilcox boiler1 steam may be raised more rapidly than in practically any other water-tube design4 ,in starting up a cold ,babcock ,wilcox boiler with either coal or oil fuel1 where a proper furnace arrangement is supplied1 steam may be raised to a pressure of #bjj pounds in less than half an hour4 ,with a ,babcock ,wilcox boiler in a test where forced draft was available1 steam was raised from an initial temperature of the boiler and its contained water of #gb degrees to a pressure of #bjj pounds1 in #ab minutes after lighting the fire4 ,the boiler also responds quickly in starting from banked fires1 especially where forced draft is available4 ,in ,babcock ,wilcox boilers the water is divided into many small streams which circulate without undue frictional resistance in thin envelopes passing through the hottest part of the furnace1 the steam being carried rapidly to the disengaging surface4 ,there is no part of the boiler exposed to the heat of the fire that is not in contact with water internally1 and as a result there is no danger of overheating on starting up quickly nor can leaks occur from unequal expansion such as might be the case where an attempt is made to raise steam rapidly in boilers using water leg construction4 ,storage ,capacity for ,steam and ,water--,where sufficient steam and water capacity are not provided in a boiler1 its action will be irregular1 the steam pressure varying over wide limits and the water level being subject to frequent and rapid fluctuation4 ,owing to the small relative weight of steam1 water capacity is of greater importance in this respect than steam space4 ,with a gauge pressure of #ahj pounds per square inch1 #h cubic feet of steam1 which is equivalent to one-half cubic foot of water space1 are required to supply one boiler horse power for one minute and if no heat be supplied to the boiler during such an interval1 the pressure will drop to #aej pounds per square inch4 ,the volume of steam space1 therefore1 may be over rated1 but if this be too small1 the steam passing off will carry water with it in the form of spray4 ,too great a water space results in slow steaming and waste of fuel in starting up2 while too much steam space adds to the radiating surface and increases the losses from that cause4 ,that the steam and water space of the ,babcock ,wilcox boiler are the result of numerous experiments has previously been pointed out4 ,accessibility--,cleaning4 ,that water-tube boilers are more accessible as a class than are fire-tube boilers has been indicated4 ,all water-tube boilers1 however1 are not equally accessible4 ,in certain designs1 due to the arrangement of baffling used it is practically impossible to remove all deposits of soot and dirt4 ,frequently1 in order to cheapen the product1 sufficient cleaning and access doors are not supplied as part of the boiler equipment4 ,the tendency of soot to collect on the crown sheets of certain vertical water-tube boilers has been noted4 ,such deposits are difficult to remove and if corrosion goes on beneath such a covering the sheet may crack and an explosion result4 ,illustration3 ,rear ,view--,longitudinal ,drum ,vertical ,header ,boiler1 ,showing ,access ,doors to ,rear ,headers ,it is almost impossible to thoroughly clean water legs internally1 and in such places also is there a tendency to unsuspected corrosion under deposits that cannot be removed4 ,in ,babcock ,wilcox boilers every portion of the interior of the heating surfaces can be reached and kept clean1 while any soot deposited on the exterior surfaces can be blown off while the boiler is under pressure4 ,inspection--,the accessibility which makes possible the thorough cleaning of all portions of the ,babcock ,wilcox boiler also provides a means for a thorough inspection4 ,drums are accessible for internal inspection by the removal of the manhole plates4 ,front headers may be inspected through large doors furnished for the purpose4 ,rear headers in the inclined header designs may be inspected from the chamber formed by such headers and the rear wall of the boiler4 ,in the vertical header designs rear tube doors are furnished1 as has been stated4 ,in certain designs of water-tube boilers in order to assure accessibility for inspection of the rear ends of the tubes1 the rear portion of the boiler is exposed to the atmosphere with resulting excessive radiation losses4 ,in other designs the means of access to the rear ends of the tubes are of a makeshift and unworkmanlike character4 ,by the removal of handhole plates1 all tubes in a ,babcock ,wilcox boiler may be inspected for their full length either for the presence of scale or for suspected corrosion4 ,repairs--,in ,babcock ,wilcox boilers the possession of great strength1 the elimination of stresses due to uneven temperatures and of the resulting danger of leaks and corrosion1 the protection of the drums from the intense heat of the fire1 and the decreased liability of the scale forming matter to lodge on the hottest tube surfaces1 all tend to minimize the necessity for repairs4 ,the tubes of the ,babcock ,wilcox boiler are practically the only part which may need renewal and these only at infrequent intervals ,when necessary1 such renewals may be made cheaply and quickly4 ,a small stock of tubes1 #d inches in diameter1 of sufficient length for the boiler used1 is all that need be carried to make renewals4 ,repairs in water-leg boilers are difficult at best and frequently unsatisfactory when completed4 ,when staybolt replacements are necessary1 in order to get at the inner sheet of the water leg1 several tubes must in some cases be cut out4 ,not infrequently a replacement of an entire water leg is necessary and this is difficult and requires a lengthy shutdown4 ,with the ,babcock ,wilcox boiler1 on the other hand1 even if it is necessary to replace a section1 this may be done in a few hours after the boiler is cool4 ,in the case of certain staybolt failures the working pressure of a repaired boiler utilizing such construction will frequently be lowered by the insurance companies when the boiler is again placed in service4 ,the sectional nature of the ,babcock ,wilcox boiler enables it to maintain its original working pressure over long periods of time1 almost regardless of the nature of any repair that may be required4 ,illustration3 #adef ,horse-power ,installation of ,babcock ,wilcox ,boilers at the ,raritan ,woolen ,mills1 ,raritan1 ,n4 ,j4 ,the ,first of ,these ,boilers were ,installed in #ahgh and #ahha and are still ,operated at #hj ,pounds ,pressure ,durability--,babcock ,wilcox boilers are being operated in every-day service with entirely satisfactory results and under the same steam pressure as that for which they were originally sold that have been operated from thirty to thirty-five years4 ,it is interesting to note in considering the life of a boiler that the length of life of a ,babcock ,wilcox boiler must be taken as the criterion of what length of life is possible4 ,this is due to the fact that there are ,babcock ,wilcox boilers in operation to-day that have been in service from a time that antedates by a considerable margin that at which the manufacturer of any other water-tube boiler now on the market was started4 ,probably the very best evidence of the value of the ,babcock ,wilcox boiler as a steam generator and of the reliability of the apparatus1 is seen in the sales of the company4 ,since the company was formed1 there have been sold throughout the world over #i1ijj1jjj horse power4 ,a feature that cannot be overlooked in the consideration of the advantages of the ,babcock ,wilcox boiler is the fact that as a part of the organization back of the boiler1 there is a body of engineers of recognized ability1 ready at all times to assist its customers in every possible way4 ,illustration3 #bdjj ,horse-power ,installation of ,babcock ,wilcox ,boilers in the ,union ,station ,power ,house of the ,pennsylvania ,railroad ,co41 ,pittsburgh1 ,pa4 ,this ,company has a ,total of #bh1ejj ,horse ,power of ,babcock ,wilcox ,boilers ,installed ,,heat ,,and ,,its ,,measurement ,the usual conception of heat is that it is a form of energy produced by the vibratory motion of the minute particles or molecules of a body4 ,all bodies are assumed to be composed of these molecules1 which are held together by mutual cohesion and yet are in a state of continual vibration4 ,the hotter a body or the more heat added to it1 the more vigorous will be the vibrations of the molecules4 ,as is well known1 the effect of heat on a body may be to change its temperature1 its volume1 or its state1 that is1 from solid to liquid or from liquid to gaseous4 ,where water is melted from ice and evaporated into steam1 the various changes are admirably described in the lecture by ,mr4 ,babcock on ,the ,theory of ,steam ,making1 given in the next chapter4 ,the change in temperature of a body is ordinarily measured by thermometers1 though for very high temperatures so-called pyrometers are used4 ,the latter are dealt with under the heading ,high ,temperature ,measurements at the end of this chapter4 ,illustration3 ,fig4 #aa ,by reason of the uniform expansion of mercury and its great sensitiveness to heat1 it is the fluid most commonly used in the construction of thermometers4 ,in all thermometers the freezing point and the boiling point of water1 under mean or average atmospheric pressure at sea level1 are assumed as two fixed points1 but the division of the scale between these two points varies in different countries4 ,the freezing point is determined by the use of melting ice and for this reason is often called the melting point4 ,there are in use three thermometer scales known as the ,fahrenheit1 the ,centigrade or ,celsius1 and the ,raumur4 ,as shown in ,fig4 #aa1 in the ,fahrenheit scale1 the space between the two fixed points is divided into #ahj parts2 the boiling point is marked #bab1 and the freezing point is marked #cb1 and zero is a temperature which1 at the time this thermometer was invented1 was incorrectly imagined to be the lowest temperature attainable4 ,in the centigrade and the ,raumur scales1 the distance between the two fixed points is divided into #ajj and #hj parts1 respectively4 ,in each of these two scales the freezing point is marked zero1 and the boiling point is marked #ajj in the centigrade and #hj in the ,raumur4 ,each of the #ahj1 #ajj or #hj divisions in the respective thermometers is called a degree4 ,table #c and appended formulae are useful for converting from one scale to another4 ,in the ,united ,states the bulbs of high-grade thermometers are usually made of either ,jena #eh;,,iii borosilicate thermometer glass or ,jena #af;,,iii glass1 the stems being made of ordinary glass4 ,the ,jena #af;,,iii glass is not suitable for use at temperatures much above #hej degrees ,fahrenheit and the harder ,jena #ei;,,iii should be used in thermometers for temperatures higher than this4 ,below the boiling point1 the hydrogen-gas thermometer is the almost universal standard with which mercurial thermometers may be compared1 while above this point the nitrogen-gas thermometer is used4 ,in both of these standards the change in temperature is measured by the change in pressure of a constant volume of the gas4 ,in graduating a mercurial thermometer for the ,fahrenheit scale1 ordinarily a degree is represented as #a_/ahj part of the volume of the stem between the readings at the melting point of ice and the boiling point of water4 ,for temperatures above the latter1 the scale is extended in degrees of the same volume4 ,for very accurate work1 however1 the thermometer may be graduated to read true-gas-scale temperatures by comparing it with the gas thermometer and marking the temperatures at #be or #ej degree intervals4 ,each degree is then #a_/be or #a_/ej of the volume of the stem in each interval4 ,every thermometer1 especially if intended for use above the boiling point1 should be suitably annealed before it is used4 ,if this is not done1 the true melting point and also the fundamental interval1 that is1 the interval between the melting and the boiling points1 may change considerably4 ,after continued use at the higher temperatures also1 the melting point will change1 so that the thermometer must be calibrated occasionally to insure accurate readings4 ,,table #c ,,comparison ,,of ,,thermometer ,,scales ---------------------------------------- ----- ,fahrenheit,centigrade ,raumur ---------------------------------------- ----- ,absolute ,zero -#dei4fd -#bgc4ac -#bah4ej #j -#ag4gh -#ad4bb #aj -#ab4bb -#i4gh #bj -#f4fg -#e4cc #cj -#a4aa -#j4hi ,freezing ,point #cb #j #j ,maximum ,density of ,water #ci4a #c4id #c4ae #ej #aj #h #ge #bc4hi #ai4aa #ajj #cg4gh #cj4bb #bjj #ic4cc #gd4fg ,boiling ,point #bab #ajj #hj #bej #aba4aa #if4hi #cjj #adh4hi #aai4aa #cej #agf4fg #ada4cc ---------------------------------------- ----- ,f #i_/e;,c#cb #i_/d,r#cb ,c #e_/i7;,f-#cb7 #e_/d,r ,r #d_/i7;,f-#cb7 #d_/e;,c ,as a general rule thermometers are graduated to read correctly for total immersion1 that is1 with bulb and stem of the thermometer at the same temperature1 and they should be used in this way when compared with a standard thermometer4 ,if the stem emerges into space either hotter or colder than that in which the bulb is placed1 a stem correction must be applied to the observed temperature in addition to any correction that may be found in the comparison with the standard4 ,for instance1 for a particular thermometer1 comparison with the standard with both fully immersed made necessary the following corrections3 ,temperature ,correction #dj;,f #j4j #ajj #j4j #bjj #j4j #cjj #b4e #djj -#j4e #ejj -#b4e ,when the sign of the correction is positive 77 it must be added to the observed reading1 and when the sign is a negative 7-7 the correction must be subtracted4 ,the formula for the stem correction is as follows3 ,stem correction #j4jjjjhe n 7,t-t7 in which ,t is the observed temperature1 t is the mean temperature of the emergent column1 n is the number of degrees of mercury column emergent1 and #j4jjjjhe is the difference between the coefficient of expansion of the mercury and that in the glass in the stem4 ,suppose the observed temperature is #djj degrees and the thermometer is immersed to the #bjj degrees mark1 so that #bjj degrees of the mercury column project into the air4 ,the mean temperature of the emergent column may be found by tying another thermometer on the stem with the bulb at the middle of the emergent mercury column as in ,fig4 #ab4 ,suppose this mean temperature is #he degrees1 then ,stem correction #j4jjjjhe #bjj 7#djj - #he7 #e4c degrees4 ,as the stem is at a lower temperature than the bulb1 the thermometer will evidently read too low1 so that this correction must be added to the observed reading to find the reading corresponding to total immersion4 ,the corrected reading will therefore be #dje4c degrees4 ,if this thermometer is to be corrected in accordance with the calibrated corrections given above1 we note that a further correction of #j4e must be applied to the observed reading at this temperature1 so that the correct temperature is #dje4c - #j4e #djd4h degrees or #dje degrees4 ,illustration3 ,fig4 #ab ,illustration3 ,fig4 #ac ,fig4 #ab shows how a stem correction can be obtained for the case just described4 ,fig4 #ac affords an opportunity for comparing the scale of a thermometer correct for total immersion with one which will read correctly when submerged to the #cjj degrees mark1 the stem being exposed at a mean temperature of #aaj degrees ,fahrenheit1 a temperature often prevailing when thermometers are used for measuring temperatures in steam mains4 ,absolute ,zero--,experiments show that at #cb degrees ,fahrenheit a perfect gas expands #a_/dia4fd part of its volume if its pressure remains constant and its temperature is increased one degree4 ,thus if gas at #cb degrees ,fahrenheit occupies #ajj cubic feet and its temperature is increased one degree1 its volume will be increased to #ajj #ajj_/dia4fd #ajj4bjc cubic feet4 ,for a rise of two degrees the volume would be #ajj 7#ajj #b7 _/ #dia4fd #ajj4djf cubic feet4 ,if this rate of expansion per one degree held good at all temperatures1 and experiment shows that it does above the freezing point1 the gas1 if its pressure remained the same1 would double its volume1 if raised to a temperature of #cb #dia4fd #ebc4fd degrees ,fahrenheit1 while under a diminution of temperature it would shrink and finally disappear at a temperature of #dia4fd - #cb #dei4fd degrees below zero ,fahrenheit4 ,while undoubtedly some change in the law would take place before the lower temperature could be reached1 there is no reason why the law may not be used within the range of temperature where it is known to hold good4 ,from this explanation it is evident that under a constant pressure the volume of a gas will vary as the number of degrees between its temperature and the temperature of -#dei4fd degrees ,fahrenheit4 ,to simplify the application of the law1 a new thermometric scale is constructed as follows3 the point corresponding to -#dfj degrees ,fahrenheit1 is taken as the zero point on the new scale1 and the degrees are identical in magnitude with those on the ,fahrenheit scale4 ,temperatures referred to this new scale are called absolute temperatures and the point -#dfj degrees ,fahrenheit 7 -#bgc degrees centigrade7 is called the absolute zero4 ,to convert any temperature ,fahrenheit to absolute temperature1 add #dfj degrees to the temperature on the ,fahrenheit scale3 thus #ed degrees ,fahrenheit will be #ed #dfj #ead degrees absolute temperature2 #aac degrees ,fahrenheit will likewise be equal to #aac #dfj #egc degrees absolute temperature4 ,if one pound of gas is at a temperature of #ed degrees ,fahrenheit and another pound is at a temperature of #aad degrees ,fahrenheit the respective volumes at a given pressure would be in the ratio of #ead to #egc4 ,illustration3 ,ninety-sixth ,street ,station of the ,new ,york ,railways ,co41 ,new ,york ,city1 ,operating #bj1jjj ,horse ,power of ,babcock ,wilcox ,boilers4 ,this ,company and its ,allied ,companies ,operate a ,total of #ajj1jjj ,horse ,power of ,babcock ,wilcox ,boilers ,british ,thermal ,unit--,the quantitative measure of heat is the ,british thermal unit1 ordinarily written ,b4 t4 u4 ,this is the quantity of heat required to raise the temperature of one pound of pure water one degree at #fb degrees ,fahrenheit2 that is1 from #fb degrees to #fc degrees4 ,in the metric system this unit is the calorie and is the heat necessary to raise the temperature of one kilogram of pure water from #ae degrees to #af degrees centigrade4 ,these two definitions lead to a discrepancy of #j4jc of #a per cent1 which is insignificant for engineering purposes1 and in the following the ,b4 t4 u4 is taken with this discrepancy ignored4 ,the discrepancy is due to the fact that there is a slight difference in the specific heat of water at #ae degrees centigrade and #fb degrees ,fahrenheit4 ,the two units may be compared thus3 #a ,calorie #c4ifh ,b4 t4 u4 #a ,b4 t4 u4 #j4beb ,calories4 ,unit ,water ,temperature ,rise #a ,b4 t4 u4 #a ,pound #a ,degree ,fahrenheit #a ,calorie #a ,kilogram #a ,degree centigrade ,but #a kilogram #b4bjdf pounds and #a degree centigrade #i_/e degree ,fahrenheit4 ,hence #a calorie 7#b4bjdf #i_/e7 #c4ifh ,b4 t4 u4 ,the heat values in ,b4 t4 u4 are ordinarily given per pound1 and the heat values in calories per kilogram1 in which case the ,b4 t4 u4 per pound are approximately equivalent to #i_/e the calories per kilogram4 ,as determined by ,joule1 heat energy has a certain definite relation to work1 one ,british thermal unit being equivalent from his determinations to #ggb foot pounds4 ,rowland1 a later investigator1 found that #ggh foot pounds were a more exact equivalent4 ,still later investigations indicate that the correct value for a ,b4 t4 u4 is #ggg4eb foot pounds or approximately #ggh4 ,the relation of heat energy to work as determined is a demonstration of the first law of thermo-dynamics1 namely1 that heat and mechanical energy are mutually convertible in the ratio of #ggh foot pounds for one ,british thermal unit4 ,this law1 algebraically expressed1 is ,w ,,jh2 ,w being the work done in foot pounds1 ,h being the heat in ,b4 t4 u41 and ,j being ,joules equivalent4 ,thus #ajjj ,b4 t4 u4's would be capable of doing #ajjj #ggh #gghjjj foot pounds of work4 ,specific ,heat--,the specific heat of a substance is the quantity of heat expressed in thermal units required to raise or lower the temperature of a unit weight of any substance at a given temperature one degree4 ,this quantity will vary for different substances ,for example1 it requires about #af ,b4 t4 u4 to raise the temperature of one pound of ice #cb degrees or #j4e ,b4 t4 u4 to raise it one degree1 while it requires approximately #ahj ,b4 t4 u4 to raise the temperature of one pound of water #ahj degrees or one ,b4 t4 u4 for one degree4 ,if then1 a pound of water be considered as a standard1 the ratio of the amount of heat required to raise a similar unit of any other substance one degree1 to the amount required to raise a pound of water one degree is known as the specific heat of that substance4 ,thus since one pound of water required one ,b4 t4 u4 to raise its temperature one degree1 and one pound of ice requires about #j4e degrees to raise its temperature one degree1 the ratio is #j4e which is the specific heat of ice4 ,to be exact1 the specific heat of ice is #j4ejd1 hence #cb degrees #j4ejd #af4abh ,b4 t4 u4 would be required to raise the temperature of one pound of ice from #j to #cb degrees4 ,for solids1 at ordinary temperatures1 the specific heat may be considered a constant for each individual substance1 although it is variable for high temperatures4 ,in the case of gases a distinction must be made between specific heat at constant volume1 and at constant pressure4 ,where specific heat is stated alone1 specific heat at ordinary temperature is implied1 and mean specific heat refers to the average value of this quantity between the temperatures named4 ,the specific heat of a mixture of gases is obtained by multiplying the specific heat of each constituent gas by the percentage by weight of that gas in the mixture1 and dividing the sum of the products by #ajj4 ,the specific heat of a gas whose composition by weight is ,,co#b1 #ac per cent2 ,,co1 #j4d per cent2 ,o1 #h per cent2 ,n1 #gh4f per cent1 is found as follows3 ,,co#b 3 #ac #j4bag #b4hba ,,co 3 #j4d #j4bdgi #j4jiiaf ,o 3 #h #j4bage #a4gdjjj ,n 3 #gh4f #j4bdch #ai4afbfh -------- #ajj4j #bc4hbbhd and #bc4hbbh #ajj #j4bch specific heat of the gas4 ,the specific heats of various solids1 liquids and gases are given in ,table #d4 ,sensible ,heat--,the heat utilized in raising the temperature of a body1 as that in raising the temperature of water from #cb degrees up to the boiling point1 is termed sensible heat4 ,in the case of water1 the sensible heat required to raise its temperature from the freezing point to the boiling point corresponding to the pressure under which ebullition occurs1 is termed the heat of the liquid4 ,latent ,heat--,latent heat is the heat which apparently disappears in producing some change in the condition of a body without increasing its temperature ,if heat be added to ice at freezing temperature1 the ice will melt but its temperature will not be raised4 ,the heat so utilized in changing the condition of the ice is the latent heat and in this particular case is known as the latent heat of fusion4 ,if heat be added to water at #bab degrees under atmospheric pressure1 the water will not become hotter but will be evaporated into steam1 the temperature of which will also be #bab degrees4 ,the heat so utilized is called the latent heat of evaporation and is the heat which apparently disappears in causing the substance to pass from a liquid to a gaseous state4 ,,table #d ,,specific ,,heats ,,of ,,various ,,substances ---------------------------------------- ---------------------------- ,,solids ---------------------------------------- -------------------------- ,temperature#b ,degrees ,specific ,fahrenheit ,heat ---------------------------------------- -------------------------- ,copper #ei-dfj 4#jiea ,gold #cb-bab 4#jcaf ,wrought ,iron #ei-bab 4#aaeb ,cast ,iron #fh-bab 4#aahi ,steel 7soft7 #fh-bjh 4#aage ,steel 7hard7 #fh-bjh 4#aafe ,zinc #cb-bab 4#jice ,brass 7yellow7 #cb 4#jhhc ,glass 7normal ther4 #af;,,iii7 #ff-bab 4#aihh ,lead #ei 4#jbii ,platinum #cb-bab 4#jcbc ,silver #cb-bab 4#jeei ,tin -#aje-fd 4#jeah ,ice 4#ejdj ,sulphur 7newly fused7 4#bjbe ---------------------------------------- -------------------------- ,,liquids ---------------------------------------- -------------------------- ,temperature#b ,degrees ,specific ,fahrenheit ,heat ---------------------------------------- -------------------------- ,water#c #ei #a4jjjj ,alcohol #cb 4#edge #agf 4#gfid ,mercury #cb 4#jccdf ,benzol #ej 4#djff #abb 4#dejb ,glycerine #ei-ajb 4#egf ,lead 7,melted7 to #cfj 4#jdaj ,sulphur 7melted7 #bdf-big 4#bcej ,tin 7melted7 4#jfcg ,sea ,water 7sp4 gr4 #a4jjdc7 #fd 4#ihj ,sea ,water 7sp4 gr4 #a4jdfc7 #fd 4#ijc ,oil of ,turpentine #cb 4#daa ,petroleum #fd-baj 4#dih ,sulphuric ,acid #fh-acc 4#ccfc ---------------------------------------- -------------------------- ,,gases ---------------------------------------- ------------------------- ,specific ,specific ,temperature#b ,heat at ,heat at ,degrees ,constant ,constant ,fahrenheit ,pressure ,volume ---------------------------------------- ------------------------- ,air #cb-cib 4#bcge 4#afic ,oxygen #dd-dje 4#bage 4#aeec ,nitrogen #cb-cib 4#bdch 4#agbi ,hydrogen #ed-chh #c4djij #b4dada ,superheated ,steam ,see table #be ,carbon ,monoxide #da-bjh 4#bdbe 4#agbh ,carbon ,dioxide #eb-dag 4#bafi 4#aece ,methane #fd-djf 4#eibi 4#deje ,blast ,fur4 ,gas 7approx47 444 4#bbgg 444 ,flue gas 7approx47 444 4#bdjj 444 ---------------------------------------- ------------------------- ,latent heat is not lost1 but reappears whenever the substances pass through a reverse cycle1 from a gaseous to a liquid1 or from a liquid to a solid state4 ,it may1 therefore1 be defined as stated1 as the heat which apparently disappears1 or is lost to thermometric measurement1 when the molecular constitution of a body is being changed4 ,latent heat is expended in performing the work of overcoming the molecular cohesion of the particles of the substance and in overcoming the resistance of external pressure to change of volume of the heated body4 ,latent heat of evaporation1 therefore1 may be said to consist of internal and external heat1 the former being utilized in overcoming the molecular resistance of the water in changing to steam1 while the latter is expended in overcoming any resistance to the increase of its volume during formation4 ,in evaporating a pound of water at #bab degrees to steam at #bab degrees1 #hig4f ,b4 t4 u4 are expended as internal latent heat and #gb4h ,b4 t4 u4 as external latent heat4 ,for a more detailed description of the changes brought about in water by sensible and latent heat1 the reader is again referred to the chapter on ,the ,theory of ,steam ,making4 ,ebullition--,the temperature of ebullition of any liquid1 or its boiling point1 may be defined as the temperature which exists where the addition of heat to the liquid no longer increases its temperature1 the heat added being absorbed or utilized in converting the liquid into vapor4 ,this temperature is dependent upon the pressure under which the liquid is evaporated1 being higher as the pressure is greater4 ,,table #e ,,boiling ,,points ,,at ,,atmospheric ,,pressure ----------------------------------- ,degrees ,fahrenheit ----------------------------------- ,ammonia #adj ,bromine #ade ,alcohol #agc ,benzine #bab ,water #bab ,average ,sea ,water #bac4b ,saturated ,brine #bbf ,mercury #fhj ----------------------------------- ,total ,heat of ,evaporation--,the quantity of heat required to raise a unit of any liquid from the freezing point to any given temperature1 and to entirely evaporate it at that temperature1 is the total heat of evaporation of the liquid for that temperature4 ,it is the sum of the heat of the liquid and the latent heat of evaporation4 ,to recapitulate1 the heat added to a body is divided as follows3 ,total heat ,heat to change the temperature heat to overcome the molecular cohesion heat to overcome the external pressure resisting an increase of volume of the body4 ,where water is converted into steam1 this total heat is divided as follows3 ,total heat ,heat to change the temperature of the water heat to separate the molecules of the water heat to overcome resistance to increase in volume of the steam1 ,heat of the liquid internal latent heat external latent heat1 ,heat of the liquid total latent heat of steam1 ,total heat of evaporation4 ,the steam tables given on pages #abb to #abg give the heat of the liquid and the total latent heat through a wide range of temperatures4 ,gases--,when heat is added to gases there is no internal work done2 hence the total heat is that required to change the temperature plus that required to do the external work4 ,if the gas is not allowed to expand but is preserved at constant volume1 the entire heat added is that required to change the temperature only4 ,linear ,expansion of ,substances by ,heat--,to find the increase in the length of a bar of any material due to an increase of temperature1 multiply the number of degrees of increase in temperature by the coefficient of expansion for one degree and by the length of the bar4 ,where the coefficient of expansion is given for #ajj degrees1 as in ,table #f1 the result should be divided by #ajj4 ,the expansion of metals per one degree rise of temperature increases slightly as high temperatures are reached1 but for all practical purposes it may be assumed to be constant for a given metal4 ,,table #f ,,lineal ,,expansion ,,of ,,solids ,,at ,,ordinary ,,temperatures 7,tabular values represent increase per foot per #ajj degrees increase in temperature1 ,fahrenheit or centigrade7 ---------------------------------------- ------------------------- ,temperature ,conditions#d;,coefficient per ,coefficient per ,substance ,degrees #ajj ,degrees #ajj ,degrees ,fahrenheit ,fahrenheit ,centigrade ---------------------------------------- ------------------------- ,brass 7cast7 #cb to #bab 4#jjajdb 4#jjahge ,brass 7wire7 #cb to #bab 4#jjajgb 4#jjaicj ,copper #cb to #bab 4#jjjibf 4#jjafff ,glass 7,english flint7 #cb to #bab 4#jjjdea 4#jjjhab ,glass 7,french flint7 #cb to #bab 4#jjjdhd 4#jjjhgb ,gold #cb to #bab 4#jjjhaf 4#jjadgj ,granite 7average7 #cb to #bab 4#jjjdhb 4#jjjhfh ,iron 7cast7 #ajd 4#jjjehi 4#jjajfa ,iron 7soft forged7 #j to #bab 4#jjjfcd 4#jjaada ,iron 7wire7 #cb to #bab 4#jjjhjj 4#jjaddj ,lead #cb to #bab 4#jjaeje 4#jjbgji ,mercury #cb to #bab 4#jjiihde 4#jagiga ,platinum #ajd 4#jjjdii 4#jjjhii ,limestone #cb to #bab 4#jjjaci 4#jjjbea ,silver #ajd 4#jjajfg 4#jjaiba ,steel 7,bessemer rolled1 hard7 #j to #bab 4#jjjef 4#jjaja ,steel 7,bessemer rolled1 soft7 #j to #bab 4#jjjfc 4#jjaag ,steel 7cast1 ,french7 #ajd 4#jjjgcd 4#jjacbb ,steel 7cast annealed1 ,english7 #ajd 4#jjjfjh 4#jjajie ---------------------------------------- ------------------------- ,high ,temperature ,measurements--,the temperatures to be dealt with in steam-boiler practice range from those of ordinary air and steam to the temperatures of burning fuel4 ,the gases of combustion1 originally at the temperature of the furnace1 cool as they pass through each successive bank of tubes in the boiler1 to nearly the temperature of the steam1 resulting in a wide range of temperatures through which definite measurements are sometimes required4 ,of the different methods devised for ascertaining these temperatures1 some of the most important are as follows3 #ast4 ,mercurial pyrometers for temperatures up to #ajjj degrees ,fahrenheit4 #bnd4 ,expansion pyrometers for temperatures up to #aejj degrees ,fahrenheit4 #crd4 ,calorimetry for temperatures up to #bjjj degrees ,fahrenheit4 #dth4 ,thermo-electric pyrometers for temperatures up to #bijj degrees ,fahrenheit4 #eth4 ,melting points of metal which flow at various temperatures up to the melting point of platinum #cbbg degrees ,fahrenheit4 #fth4 ,radiation pyrometers for temperatures up to #cfjj degrees ,fahrenheit4 #gth4 ,optical pyrometers capable of measuring temperatures up to #ab1fjj degrees ,fahrenheit4#f ,for ordinary boiler practice however1 their range is #afjj to #cfjj degrees ,fahrenheit4 ,illustration3 #bbh ,horse-power ,babcock ,wilcox ,boiler1 ,installed at the ,wentworth ,institute1 ,boston1 ,mass4 ,table #g gives the degree of accuracy of high temperature measurements4 ,,table #g ,,accuracy ,,of ,,high ,,temperature ,,measurements#g ---------------------------------------- -------- ,centigrade ,fahrenheit ---------------------------------------- ------ ,accuracy ,accuracy ,temperature ,plus or ,temperature ,plus or ,range ,minus ,range ,minus ,degrees ,degrees ---------------------------------------- ------ #bjj- #ejj #j4e #cib- #icb #j4i #ejj- #hjj #b #icb-adgb #c4f #hjj-aajj #c #adgb-bjab #e4d #aajj-afjj #ae #bjab-biab #bg #afjj-bjjj #be #biab-cfcb #de ---------------------------------------- ------ ,mercurial ,pyrometers--,at atmospheric pressure mercury boils at #fgf degrees ,fahrenheit and even at lower temperatures the mercury in thermometers will be distilled and will collect in the upper part of the stem4 ,therefore1 for temperatures much above #djj degrees ,fahrenheit1 some inert gas1 such as nitrogen or carbon dioxide1 must be forced under pressure into the upper part of the thermometer stem4 ,the pressure at #fjj degrees ,fahrenheit is about #ae pounds1 or slightly above that of the atmosphere1 at #hej degrees about #gj pounds1 and at #ajjj degrees about #cjj pounds4 ,flue-gas temperatures are nearly always taken with mercurial thermometers as they are the most accurate and are easy to read and manipulate4 ,care must be taken that the bulb of the instrument projects into the path of the moving gases in order that the temperature may truly represent the flue gas temperature4 ,no readings should be considered until the thermometer has been in place long enough to heat it up to the full temperature of the gases4 ,expansion ,pyrometers--,brass expands about #ej per cent more than iron and in both brass and iron the expansion is nearly proportional to the increase in temperature4 ,this phenomenon is utilized in expansion pyrometers by enclosing a brass rod in an iron pipe1 one end of the rod being rigidly attached to a cap at the end of the pipe1 while the other is connected by a multiplying gear to a pointer moving around a graduated dial4 ,the whole length of the expansion piece must be at a uniform temperature before a correct reading can be obtained4 ,this fact1 together with the lost motion which is likely to exist in the mechanism connected to the pointer1 makes the expansion pyrometer unreliable2 it should be used only when its limitations are thoroughly understood and it should be carefully calibrated4 ,unless the brass and iron are known to be of the same temperature1 its action will be anomalous3 for instance1 if it be allowed to cool after being exposed to a high temperature1 the needle will rise before it begins to fall4 ,similarly1 a rise in temperature is first shown by the instrument as a fall4 ,the explanation is that the iron1 being on the outside1 heats or cools more quickly than the brass4 ,calorimetry--,this method derives its name from the fact that the process is the same as the determination of the specific heat of a substance by the water calorimeter1 except that in one case the temperature is known and the specific heat is required1 while in the other the specific heat is known and the temperature is required4 ,the temperature is found as follows3 ,a given weight of some substance such as iron1 nickel or fire brick1 is heated to the unknown temperature and then plunged into water and the rise in temperature noted4 ,if ,x temperature to be measured1 w weight of heated body in pounds1 ,w weight of water in pounds1 ,t final temperature of water1 t difference between initial and final temperatures of water1 s known specific heat of body4 ,then ,x ,t ,wt ws ,any temperatures secured by this method are affected by so many sources of error that the results are very approximate4 ,thermo-electric ,pyrometers--,when wires of two different metals are joined at one end and heated1 an electromotive force will be set up between the free ends of the wires4 ,its amount will depend upon the composition of the wires and the difference in temperature between the two4 ,if a delicate galvanometer of high resistance be connected to the thermal couple1 as it is called1 the deflection of the needle1 after a careful calibration1 will indicate the temperature very accurately4 ,in the thermo-electric pyrometer of ,le ,chatelier1 the wires used are platinum and a #aj per cent alloy of platinum and rhodium1 enclosed in porcelain tubes to protect them from the oxidizing influence of the furnace gases4 ,the couple with its protecting tubes is called an element4 ,the elements are made in different lengths to suit conditions4 ,it is not necessary for accuracy to expose the whole length of the element to the temperature to be measured1 as the electromotive force depends only upon the temperature of the juncture at the closed end of the protecting tube and that of the cold end of the element4 ,the galvanometer can be located at any convenient point1 since the length of the wires leading to it simply alter the resistance of the circuit1 for which allowance may be made4 ,the advantages of the thermo-electric pyrometer are accuracy over a wide range of temperatures1 continuity of readings1 and the ease with which observations can be taken4 ,its disadvantages are high first cost and1 in some cases1 extreme delicacy4 ,melting ,points of ,metals--,the approximate temperature of a furnace or flue may be determined1 if so desired1 by introducing certain metals of which the melting points are known4 ,the more common metals form a series in which the respective melting points differ by #ajj to #bjj degrees ,fahrenheit1 and by using these in order1 the temperature can be fixed between the melting points of some two of them4 ,this method lacks accuracy1 but it suffices for determinations where approximate readings are satisfactory4 ,the approximate melting points of certain metals that may be used for determinations of this nature are given in ,table #h4 ,radiation ,pyrometers--,these are similar to thermo-electric pyrometers in that a thermo-couple is employed4 ,the heat rays given out by the hot body fall on a concave mirror and are brought to a focus at a point at which is placed the junction of a thermo-couple4 ,the temperature readings are obtained from an indicator similar to that used with thermo-electric pyrometers4 ,optical ,pyrometers--,of the optical pyrometers the ,wanner is perhaps the most reliable4 ,the principle on which this instrument is constructed is that of comparing the quantity of light emanating from the heated body with a constant source of light1 in this case a two-volt osmium lamp4 ,the lamp is placed at one end of an optical tube1 while at the other an eyepiece is provided and a scale4 ,a battery of cells furnishes the current for the lamp4 ,on looking through the pyrometer1 a circle of red light appears1 divided into distinct halves of different intensities4 ,adjustment may be made so that the two halves appear alike and a reading is then taken from the scale4 ,the temperatures are obtained from a table of temperatures corresponding to scale readings4 ,for standardizing the osmium lamp1 an amylacetate lamp1 is provided with a stand for holding the optical tube4 ,,table #h ,,approximate ,,melting ,,points ,,of ,,metals#h ----------------------------------- ,metal ,temperature ,degrees ,fahrenheit ----------------------------------- ,wrought ,iron #bgcg ,pig ,iron 7gray7 #baij-bcbg ,cast ,iron 7white7 #bjge ,steel #bdfj-beej ,steel 7cast7 #bejj ,copper #aiha ,zinc #ghf ,antimony #aaff ,lead #fba ,bismuth #dih ,tin #ddi ,platinum #caia ,gold #aidf ,silver #agfb ,aluminum #abaf ----------------------------------- ,determination of ,temperature from ,character of ,emitted ,light--,as a further means of determining approximately the temperature of a furnace1 ,table #i1 compiled by ,messrs4 ,white ,taylor1 may be of service4 ,the color at a given temperature is approximately the same for all kinds of combustibles under similar conditions4 ,,table #i ,,character ,,of ,,emitted ,,light ,,and ,,corresponding ,,approximate ,,temperature#i ---------------------------------------- --------- ,character of ,emitted ,light ,temperature ,degrees ,fahrenheit ---------------------------------------- --------- ,dark red1 blood red1 low red #ajej ,dark cherry red #aage ,cherry1 full red #acge ,light cherry1 bright cherry1 light red #aeej ,orange #afej ,light orange #agbe ,yellow #ahbe ,light yellow #aige ,white #bbjj ---------------------------------------- --------- ,,the ,,theory ,,of ,,steam ,,making ,extracts from a ,lecture delivered by ,george ,h4 ,babcock1 at ,cornell ,university1 #ahhgaj ,the chemical compound known as ,h#b,o exists in three states or conditions--ice1 water and steam2 the only difference between these states or conditions is in the presence or absence of a quantity of energy exhibited partly in the form of heat and partly in molecular activity1 which1 for want of a better name1 we are accustomed to call latent heat2 and to transform it from one state to another we have only to supply or extract heat4 ,for instance1 if we take a quantity of ice1 say one pound1 at absolute zero#aa and supply heat1 the first effect is to raise its temperature until it arrives at a point #dib ,fahrenheit degrees above the starting point4 ,here it stops growing warmer1 though we keep on adding heat4 ,it1 however1 changes from ice to water1 and when we have added sufficient heat to have made it1 had it remained ice1 #bhc degrees hotter or a temperature of #cae degrees ,fahrenheit's thermometer1 it has all become water1 at the same temperature at which it commenced to change1 namely1 #dib degrees above absolute zero1 or #cb degrees by ,fahrenheit's scale4 ,let us still continue to add heat1 and it will now grow warmer again1 though at a slower rate--that is1 it now takes about double the quantity of heat to raise the pound one degree that it did before--until it reaches a temperature of #bab degrees ,fahrenheit1 or #fgb degrees absolute 7assuming that we are at the level of the sea74 ,here we find another critical point4 ,however much more heat we may apply1 the water1 as water1 at that pressure1 cannot be heated any hotter1 but changes on the addition of heat to steam2 and it is not until we have added heat enough to have raised the temperature of the water #iff degrees1 or to #a1agh degrees by ,fahrenheit's thermometer 7presuming for the moment that its specific heat has not changed since it became water71 that it has all become steam1 which steam1 nevertheless1 is at the temperature of #bab degrees1 at which the water began to change4 ,thus over four-fifths of the heat which has been added to the water has disappeared1 or become insensible in the steam to any of our instruments4 ,it follows that if we could reduce steam at atmospheric pressure to water1 without loss of heat1 the heat stored within it would cause the water to be red hot2 and if we could further change it to a solid1 like ice1 without loss of heat1 the solid would be white hot1 or hotter than melted steel--it being assumed1 of course1 that the specific heat of the water and ice remain normal1 or the same as they respectively are at the freezing point4 ,after steam has been formed1 a further addition of heat increases the temperature again at a much faster ratio to the quantity of heat added1 which ratio also varies according as we maintain a constant pressure or a constant volume2 and ,i am not aware that any other critical point exists where this will cease to be the fact until we arrive at that very high temperature1 known as the point of dissociation1 at which it becomes resolved into its original gases4 ,the heat which has been absorbed by one pound of water to convert it into a pound of steam at atmospheric pressure is sufficient to have melted #c pounds of steel or #ac pounds of gold4 ,this has been transformed into something besides heat2 stored up to reappear as heat when the process is reversed4 ,that condition is what we are pleased to call latent heat1 and in it resides mainly the ability of the steam to do work4 ,graph3 ,temperature in ,fahrenheit ,degrees 7from ,absolute ,zero7 against ,quantity of ,heat in ,british ,thermal ,units ,the diagram shows graphically the relation of heat to temperature1 the horizontal scale being quantity of heat in ,british thermal units1 and the vertical temperature in ,fahrenheit degrees1 both reckoned from absolute zero and by the usual scale4 ,the dotted lines for ice and water show the temperature which would have been obtained if the conditions had not changed4 ,the lines marked gold and steel show the relation to heat and temperature and the melting points of these metals4 ,all the inclined lines would be slightly curved if attention had been paid to the changing specific heat1 but the curvature would be small4 ,it is worth noting that1 with one or two exceptions1 the curves of all substances lie between the vertical and that for water4 ,that is to say1 that water has a greater capacity for heat than all other substances except two1 hydrogen and bromine4 ,in order to generate steam1 then1 only two steps are required3 #ast1 procure the heat1 and #bnd1 transfer it to the water4 ,now1 you have it laid down as an axiom that when a body has been transferred or transformed from one place or state into another1 the same work has been done and the same energy expended1 whatever may have been the intermediate steps or conditions1 or whatever the apparatus4 ,therefore1 when a given quantity of water at a given temperature has been made into steam at a given temperature1 a certain definite work has been done1 and a certain amount of energy expended1 from whatever the heat may have been obtained1 or whatever boiler may have been employed for the purpose4 ,a pound of coal or any other fuel has a definite heat producing capacity1 and is capable of evaporating a definite quantity of water under given conditions4 ,that is the limit beyond which even perfection cannot go1 and yet ,i have known1 and doubtless you have heard of1 cases where inventors have claimed1 and so-called engineers have certified to1 much higher results4 ,the first step in generating steam is in burning the fuel to the best advantage4 ,a pound of carbon will generate #ad1ejj ,british thermal units1 during combustion into carbonic dioxide1 and this will be the same1 whatever the temperature or the rapidity at which the combustion may take place4 ,if possible1 we might oxidize it at as slow a rate as that with which iron rusts or wood rots in the open air1 or we might burn it with the rapidity of gunpowder1 a ton in a second1 yet the total heat generated would be precisely the same4 ,again1 we may keep the temperature down to the lowest point at which combustion can take place1 by bringing large bodies of air in contact with it1 or otherwise1 or we may supply it with just the right quantity of pure oxygen1 and burn it at a temperature approaching that of dissociation1 and still the heat units given off will be neither more nor less4 ,it follows1 therefore1 that great latitude in the manner or rapidity of combustion may be taken without affecting the quantity of heat generated4 ,but in practice it is found that other considerations limit this latitude1 and that there are certain conditions necessary in order to get the most available heat from a pound of coal4 ,there are three ways1 and only three1 in which the heat developed by the combustion of coal in a steam boiler furnace may be expended4 #ast1 and principally4 ,it should be conveyed to the water in the boiler1 and be utilized in the production of steam4 ,to be perfect1 a boiler should so utilize all the heat of combustion1 but there are no perfect boilers4 #bnd4 ,a portion of the heat of combustion is conveyed up the chimney in the waste gases4 ,this is in proportion to the weight of the gases1 and the difference between their temperature and that of the air and coal before they entered the fire4 #crd4 ,another portion is dissipated by radiation from the sides of the furnace4 ,in a stove the heat is all used in these latter two ways1 either it goes off through the chimney or is radiated into the surrounding space4 ,it is one of the principal problems of boiler engineering to render the amount of heat thus lost as small as possible4 ,the loss from radiation is in proportion to the amount of surface1 its nature1 its temperature1 and the time it is exposed4 ,this loss can be almost entirely eliminated by thick walls and a smooth white or polished surface1 but its amount is ordinarily so small that these extraordinary precautions do not pay in practice4 ,it is evident that the temperature of the escaping gases cannot be brought below that of the absorbing surfaces1 while it may be much greater even to that of the fire4 ,this is supposing that all of the escaping gases have passed through the fire4 ,in case air is allowed to leak into the flues1 and mingle with the gases after they have left the heating surfaces1 the temperature may be brought down to almost any point above that of the atmosphere1 but without any reduction in the amount of heat wasted4 ,it is in this way that those low chimney temperatures are sometimes attained which pass for proof of economy with the unobserving4 ,all surplus air admitted to the fire1 or to the gases before they leave the heating surfaces1 increases the losses4 ,we are now prepared to see why and how the temperature and the rapidity of combustion in the boiler furnace affect the economy1 and that though the amount of heat developed may be the same1 the heat available for the generation of steam may be much less with one rate or temperature of combustion than another4 ,assuming that there is no air passing up the chimney other than that which has passed through the fire1 the higher the temperature of the fire and the lower that of the escaping gases the better the economy1 for the losses by the chimney gases will bear the same proportion to the heat generated by the combustion as the temperature of those gases bears to the temperature of the fire4 ,that is to say1 if the temperature of the fire is #bejj degrees and that of the chimney gases #ejj degrees above that of the atmosphere1 the loss by the chimney will be #ejj_/bejj #bj per cent4 ,therefore1 as the escaping gases cannot be brought below the temperature of the absorbing surface1 which is practically a fixed quantity1 the temperature of the fire must be high in order to secure good economy4 ,the losses by radiation being practically proportioned to the time occupied1 the more coal burned in a given furnace in a given time1 the less will be the proportionate loss from that cause4 ,it therefore follows that we should burn our coal rapidly and at a high temperature to secure the best available economy4 ,illustration3 ,portion of #ihhj ,horse-power ,installation of ,babcock ,wilcox ,boilers and ,superheaters1 ,equipped with ,babcock ,wilcox ,chain ,grate ,stokers at the ,south ,side ,elevated ,ry4 ,co41 ,chicago1 ,ill4 ,,properties ,,of ,,water ,pure water is a chemical compound of one volume of oxygen and two volumes of hydrogen1 its chemical symbol being ,h#b,o4 ,the weight of water depends upon its temperature4 ,its weight at four temperatures1 much used in physical calculations1 is given in ,table #aj4 ,,table #aj ,,weight ,,of ,,water ,,at ,,temperatures ,,used ,,in ,,physical ,,calculations ---------------------------------------- ------- ,temperature ,degrees ,weight per,weight per ,fahrenheit ,cubic ,foot,cubic ,inch ,pounds ,pounds ---------------------------------------- ------- ,at #cb degrees or freezing point at sea level #fb4dah #j4jcfab ,at #ci4b degrees or point of maximum density #fb4dbg #j4jcfac ,at #fb degrees or standard temperature #fb4cee #j4jcfjh ,at #bab degrees or boiling point at sea level #ei4hdf #j4jcdfi ---------------------------------------- ------- ,while authorities differ as to the weight of water1 the range of values given for #fb degrees ,fahrenheit 7the standard temperature ordinarily taken7 being from #fb4bia pounds to #fb4cfj pounds per cubic foot1 the value #fb4cee is generally accepted as the most accurate4 ,a ,united ,states standard gallon holds #bca cubic inches and weighs1 at #fb degrees ,fahrenheit1 approximately #h-a_/c pounds4 ,a ,british ,imperial gallon holds #bgg4db cubic inches and weighs1 at #fb degrees ,fahrenheit1 #aj pounds4 ,the above are the true weights corrected for the effect of the buoyancy of the air1 or the weight in vacuo4 ,if water is weighed in air in the ordinary way1 there is a correction of about one-eighth of one per cent which is usually negligible4 ,,table #aa ,,volume ,,and ,,weight ,,of ,,distilled ,,water ,,at ,,various ,,temperatures#ab ------------------------------------ ,temperature,relative ,volume,weight per ,degrees ,water at #ci4b ,cubic ,foot ,fahrenheit ,degrees #a ,pounds ------------------------------------ #cb #a4jjjagf #fb4db #ci4b #a4jjjjjj #fb4dc #dj #a4jjjjjd #fb4dc #ej #a4jjjbg #fb4db #fj #a4jjjif #fb4cg #gj #a4jjbja #fb4cj #hj #a4jjcch #fb4bb #ij #a4jjejd #fb4aa #ajj #a4jjfih #fb4jj #aaj #a4jjiae #fa4hf #abj #a4jaaeg #fa4ga #acj #a4jadbj #fa4ee #adj #a4jagje #fa4ch #aej #a4jbjaa #fa4bj #afj #a4jbccg #fa4jj #agj #a4jbfhb #fj4hj #ahj #a4jcjdg #fj4eh #aij #a4jcdca #fj4cf #bjj #a4jchce #fj4ab #baj #a4jdbef #ei4hh #bab #a4jdcdc #ei4hc #bbj #a4jdfi #ei4fc #bcj #a4jeae #ei4cg #bdj #a4jefb #ei4aa #bej #a4jfaa #eh4hc #bfj #a4jffb #eh4ee #bgj #a4jgae #eh4bf #bhj #a4jgga #eg4if #bij #a4jhcj #eg4fe #cjj #a4jhij #eg4cc #caj #a4jiec #eg4jj #cbj #a4ajai #ef4ff #ccj #a4ajhh #ef4cj #cdj #a4aafj #ee4id #cej #a4abce #ee4eg #cfj #a4acac #ee4ah #cgj #a4acif #ed4gh #chj #a4adhc #ed4cf #cij #a4aegc #ec4id #djj #a4afg #ec4e #daj #a4agg #ec4j #dbj #a4ahg #eb4f #dcj #a4aig #eb4b #ddj #a4bjh #ea4g #dej #a4bbj #ea4b #dfj #a4bcb #ej4g #dgj #a4bdd #ej4b #dhj #a4bef #di4g #dij #a4bfi #di4b #ejj #a4bhc #dh4g #eaj #a4big #dh4a #ebj #a4cab #dg4f #ecj #a4cbi #dg4j #edj #a4ce #df4c #eej #a4cg #de4f #efj #a4ci #dd4i ------------------------------------ ,water is but slightly compressible and for all practical purposes may be considered non-compressible4 ,the coefficient of compressibility ranges from #j4jjjjdj to #j4jjjjea per atmosphere at ordinary temperatures1 this coefficient decreasing as the temperature increases4 ,table #aa gives the weight in vacuo and the relative volume of a cubic foot of distilled water at various temperatures4 ,the weight of water at the standard temperature being taken as #fb4cee pounds per cubic foot1 the pressure exerted by the column of water of any stated height1 and conversely the height of any column required to produce a stated pressure1 may be computed as follows3 ,the pressure in pounds per square foot #fb4cee height of column in feet4 ,the pressure in pounds per square inch #j4dcc height of column in feet4 ,height of column in feet pressure in pounds per square foot #fb4cee4 ,height of column in feet pressure in pounds per square inch #j4dcc4 ,height of column in inches pressure in pounds per square inch #bg4ga4 ,height of column in inches pressure in ounces per square inch #a4gc4 ,by a change in the weights given above1 the pressure exerted and height of column may be computed for temperatures other than #fb degrees4 ,a pressure of one pound per square inch is exerted by a column of water #b4cjic feet or #bg4ga inches high at #fb degrees ,fahrenheit4 ,water in its natural state is never found absolutely pure4 ,in solvent power water has a greater range than any other liquid4 ,for common salt1 this is approximately a constant at all temperatures1 while with such impurities as magnesium and sodium sulphates1 this solvent power increases with an increase in temperature4 ,,table #ab ,,boiling ,,point ,,of ,,water ,,at ,,various ,,altitudes ---------------------------------------- ------------------ ,boiling ,point ,altitude ,above ,atmospheric ,barometer ,degrees ,sea ,level ,pressure ,reduced ,fahrenheit ,feet ,pounds per to #cb ,degrees ,square ,inch ,inches ---------------------------------------- ------------------ #ahd #aebba #h4bj #af4gj #ahe #adfdi #h4ch #ag4jf #ahf #adjge #h4eg #ag4de #ahg #acdih #h4gf #ag4hc #ahh #abicd #h4ie #ah4bb #ahi #abcfg #i4ad #ah4fa #aij #aagii #i4cd #ai4jb #aia #aabdc #i4ed #ai4dc #aib #ajfhe #i4gd #ai4he #aic #ajabg #i4ie #bj4bg #aid #iegi #aj4ag #bj4ga #aie #ijca #aj4ci #ba4ae #aif #hdha #aj4fa #ba4fj #aig #gicb #aj4hc #bb4je #aih #gcha #aa4jf #bb4eb #aii #fhdc #aa4bi #bb4ii #bjj #fcjd #aa4eb #bc4dg #bja #egfd #aa4gf #bc4ie #bjb #ebbe #ab4ja #bd4de #bjc #dfig #ab4bf #bd4if #bjd #dafi #ab4ea #be4dh #bje #cfdb #ab4gg #bf4jj #bjf #caae #ac4jc #bf4ec #bjg #behi #ac4cj #bg4jh #bjh #bjfc #ac4eg #bg4fc #bji #aeci #ac4he #bh4ai #baj #ajbe #ad4ac #bh4gf #baa #eab #ad4da #bi4cc #bab ,sea ,level #ad4gj #bi4ib ---------------------------------------- ------------------ ,sea water contains on an average approximately #c4abe per cent of its weight of solid matter or a thirty-second part of the weight of the water and salt held in solution4 ,the approximate composition of this solid matter will be3 sodium chloride #gf per cent1 magnesium chloride #aj per cent1 magnesium sulphate #f per cent1 calcium sulphate #e per cent1 calcium carbonate #j4e per cent1 other substances #b4e per cent4 ,illustration3 #gbjj ,horse-power ,installation of ,babcock ,wilcox ,boilers and ,superheaters at the ,capital ,traction ,co41 ,washington1 ,d4 ,c4 ,the boiling point of water decreases as the altitude above sea level increases4 ,table #ab gives the variation in the boiling point with the altitude4 ,water has a greater specific heat or heat-absorbing capacity than any other known substance 7bromine and hydrogen excepted7 and its specific heat is the basis for measurement of the capacity of heat absorption of all other substances4 ,from the definition1 the specific heat of water is the number of ,british thermal units required to raise one pound of water one degree4 ,this specific heat varies with the temperature of the water4 ,the generally accepted values are given in ,table #ac1 which indicates the values as determined by ,messrs4 ,marks and ,davis and ,mr4 ,peabody4 ,,table #ac ,,specific ,,heat ,,of ,,water ,,at ,,various ,,temperatures ---------------------------------------- -------------- ,,marks ,,and ,,davis ,,peabody ,from ,values of ,from ,values of ,barnes and ,dieterici ,barnes and ,regnault ---------------------------------------- ------------ ,temperature ,specific ,temperature ,specific ----------- ,heat -------------------- ,heat ,degrees ,degrees ,degrees ,fahrenheit ,centigrade,fahrenheit ---------------------------------------- ----------- #cj #a4jjih #j #cb #a4jjid #dj #a4jjde #e #da #a4jjec #ej #a4jjab #aj #ej #a4jjbc #ee #a4jjjj #ae #ei #a4jjjc #fj #j4iiij #af4aa #fa #a4jjjj #gj #j4iigg #bj #fh #j4iiij #hj #j4iigj #be #gg #j4iiha #ij #j4iifg #cj #hf #j4iigf #ajj #j4iifg #ce #ie #j4iigd #aaj #j4iigj #dj #ajd #j4iigd #abj #j4iigd #de #aac #j4iigf #acj #j4iigi #ej #abb #j4iihj #adj #j4iihf #ee #aca #j4iihe #aej #j4iiid #fj #adj #j4iiid #afj #a4jjjb #fe #adi #a4jjjd #agj #a4jjaj #gj #aeh #a4jjae #ahj #a4jjai #ge #afg #a4jjbh #aij #a4jjbi #hj #agf #a4jjdb #bjj #a4jjci #he #ahe #a4jjef #baj #a4jjeb #ij #aid #a4jjga #bbj #a4jjg #ie #bjc #a4jjhf #bcj #a4jji #ajj #bab #a4jaja ---------------------------------------- ----------- ,in consequence of this variation in specific heat1 the variation in the heat of the liquid of the water at different temperatures is not a constant4 ,table #bbac gives the heat of the liquid in a pound of water at temperatures ranging from #cb to #cdj degrees ,fahrenheit4 ,the specific heat of ice at #cb degrees is #j4dfc4 ,the specific heat of saturated steam 7ice and saturated steam representing the other forms in which water may exist71 is something that is difficult to define in any way which will not be misleading4 ,when no liquid is present the specific heat of saturated steam is negative4#ad ,the use of the value of the specific heat of steam is practically limited to instances where superheat is present1 and the specific heat of superheated steam is covered later in the book4 ,,boiler ,,feed ,,water ,all natural waters contain some impurities which1 when introduced into a boiler1 may appear as solids4 ,in view of the apparent present-day tendency toward large size boiler units and high overloads1 the importance of the use of pure water for boiler feed purposes cannot be over-estimated4 ,ordinarily1 when water of sufficient purity for such use is not at hand1 the supply available may be rendered suitable by some process of treatment4 ,against the cost of such treatment1 there are many factors to be considered4 ,with water in which there is a marked tendency toward scale formation1 the interest and depreciation on the added boiler units necessary to allow for the systematic cleaning of certain units must be taken into consideration4 ,again there is a considerable loss in taking boilers off for cleaning and replacing them on the line4 ,on the other hand1 the decrease in capacity and efficiency accompanying an increased incrustation of boilers in use has been too generally discussed to need repetition here4 ,many experiments have been made and actual figures reported as to this decrease1 but in general1 such figures apply only to the particular set of conditions found in the plant where the boiler in question was tested4 ,so many factors enter into the effect of scale on capacity and economy that it is impossible to give any accurate figures on such decrease that will serve all cases1 but that it is large has been thoroughly proven4 ,while it is almost invariably true that practically any cost of treatment will pay a return on the investment of the apparatus1 the fact must not be overlooked that there are certain waters which should never be used for boiler feed purposes and which no treatment can render suitable for such purpose4 ,in such cases1 the only remedy is the securing of other feed supply or the employment of evaporators for distilling the feed water as in marine service4 ,,table #ad ,,approximate ,,classification ,,of ,,impurities ,,found ,,in ,,feed ,,waters ,,their ,,effect ,,and ,,ordinary ,,methods ,,of ,,relief ---------------------------------------- -------------------------- ,difficulty ,resulting ,nature of ,ordinary ,method of from ,presence of ,difficulty ,overcoming or ,relieving ---------------------------------------- -------------------------- ,sediment1 ,mud1 etc4 ,incrustation ,settling tanks1 filtration1 blowing down4 ,readily ,soluble ,salts ,incrustation ,blowing down4 ,bicarbonates of ,lime1 ,incrustation ,heating feed4 ,treatment by ,magnesia1 etc4 addition of lime or of lime and soda4 ,barium carbonate4 ,sulphate of ,lime ,incrustation ,treatment by addition of soda4 ,barium carbonate4 ,chloride and ,sulphate ,corrosion ,treatment by addition of of ,magnesium carbonate of soda4 ,acid ,corrosion ,alkali4 ,dissolved ,carbonic ,corrosion ,heating feed4 ,keeping air ,acid and ,oxygen from feed4 ,addition of caustic soda or slacked lime4 ,grease ,corrosion ,filter4 ,iron alum as coagulent4 ,neutralization by carbonate of soda4 ,use of best hydrocarbon oils4 ,organic ,matter ,corrosion ,filter4 ,use of coagulent4 ,organic ,matter ,priming ,settling tanks4 ,filter in 7,sewage7 connection with coagulent4 ,carbonate of ,soda in ,priming ,barium carbonate4 ,new feed large quantities supply4 ,if from treatment1 change4 ---------------------------------------- -------------------------- ,it is evident that the whole subject of boiler feed waters and their treatment is one for the chemist rather than for the engineer4 ,a brief outline of the difficulties that may be experienced from the use of poor feed water and a suggestion as to a method of overcoming certain of these difficulties is all that will be attempted here4 ,such a brief outline of the subject1 however1 will indicate the necessity for a chemical analysis of any water before a treatment is tried and the necessity of adapting the treatment in each case to the nature of the difficulties that may be experienced4 ,table #ad gives a list of impurities which may be found in boiler feed water1 grouped according to their effect on boiler operation and giving the customary method used for overcoming difficulty to which they lead4 ,scale--,scale is formed on boiler heating surfaces by the depositing of impurities in the feed water in the form of a more or less hard adherent crust4 ,such deposits are due to the fact that water loses its soluble power at high temperatures or because the concentration becomes so high1 due to evaporation1 that the impurities crystallize and adhere to the boiler surfaces4 ,the opportunity for formation of scale in a boiler will be apparent when it is realized that during a month's operation of a #ajj horse-power boiler1 #cjj pounds of solid matter may be deposited from water containing only #g grains per gallon1 while some spring and well waters contain sufficient to cause a deposit of as high as #bjjj pounds4 ,the salts usually responsible for such incrustation are the carbonates and sulphates of lime and magnesia1 and boiler feed treatment in general deals with the getting rid of these salts more or less completely4 ,,table #ae ,,solubility ,,of ,,mineral ,,salts ,,in ,,water 7,,sparks7 ,,in ,,grains ,,per ,u4 ,s4 ,,gallon 7#eh1cha ,,grains71 ,,except ,,as ,,noted ---------------------------------------- --------------- ,temperature ,degrees ,fahrenheit #fj ,degrees #bab ,degrees ---------------------------------------- --------------- ,calcium ,carbonate #b4e #a4e ,calcium ,sulphate #adj4j #abe4j ,magnesium ,carbonate #a4j #a4h ,magnesium ,sulphate #c4j pounds #ab4j pounds ,sodium ,chloride #c4e pounds #d4j pounds ,sodium ,sulphate #a4a pounds #e4j pounds ---------------------------------------- --------------- ,,calcium ,,sulphate ,,at ,,temperature ,,above #bab ,,degrees 7,,christie7 ---------------------------------------- ------------ ,temperature degrees ,fahrenheit#bhd #cbi #cdg-cfe #dfddhb ,corresponding gauge pressure #ch #hg #aae-adi #dfiefa ,grains per gallon #de4ecb4g #ae4g #aj4ei4c ---------------------------------------- ------------ ,table #ae gives the solubility of these mineral salts in water at various temperatures in grains per ,u4 ,s4 gallon 7#eh1cha grains74 ,it will be seen from this table that the carbonates of lime and magnesium are not soluble above #bab degrees1 and calcium sulphate while somewhat insoluble above #bab degrees becomes more greatly so as the temperature increases4 ,scale is also formed by the settling of mud and sediment carried in suspension in water4 ,this may bake or be cemented to a hard scale when mixed with other scale-forming ingredients4 ,corrosion--,corrosion1 or a chemical action leading to the actual destruction of the boiler metal1 is due to the solvent or oxidizing properties of the feed water4 ,it results from the presence of acid1 either free or developed#ae in the feed1 the admixture of air with the feed water1 or as a result of a galvanic action4 ,in boilers it takes several forms3 #ast4 ,pitting1 which consists of isolated spots of active corrosion which does not attack the boiler as a whole4 #bnd4 ,general corrosion1 produced by naturally acid waters and where the amount is so even and continuous that no accurate estimate of the metal eaten away may be made4 #crd4 ,grooving1 which1 while largely a mechanical action which may occur in neutral waters1 is intensified by acidity4 ,foaming--,this phenomenon1 which ordinarily occurs with waters contaminated with sewage or organic growths1 is due to the fact that the suspended particles collect on the surface of the water in the boiler and render difficult the liberation of steam bubbles arising to that surface4 ,it sometimes occurs with water containing carbonates in solution in which a light flocculent precipitate will be formed on the surface of the water4 ,again1 it is the result of an excess of sodium carbonate used in treatment for some other difficulty where animal or vegetable oil finds its way into the boiler4 ,priming--,priming1 or the passing off of steam from a boiler in belches1 is caused by the concentration of sodium carbonate1 sodium sulphate or sodium chloride in solution4 ,sodium sulphate is found in many southern waters and also where calcium or magnesium sulphate is precipitated with soda ash4 ,treatment of ,feed ,water--,for scale formation4 ,the treatment of feed water1 carrying scale-forming ingredients1 is along two main lines3 #ast1 by chemical means by which such impurities as are carried by the water are caused to precipitate2 and #bnd1 by the means of heat1 which results in the reduction of the power of water to hold certain salts in solution4 ,the latter method alone is sufficient in the case of certain temporarily hard waters1 but the heat treatment1 in general1 is used in connection with a chemical treatment to assist the latter4 ,before going further into detail as to the treatment of water1 it may be well to define certain terms used4 ,hardness1 which is the most widely known evidence of the presence in water of scale-forming matter1 is that quality1 the variation of which makes it more difficult to obtain a lather or suds from soap in one water than in another4 ,this action is made use of in the soap test for hardness described later4 ,hardness is ordinarily classed as either temporary or permanent4 ,temporarily hard waters are those containing carbonates of lime and magnesium1 which may be precipitated by boiling at #bab degrees and which1 if they contain no other scale-forming ingredients1 become soft under such treatment4 ,permanently hard waters are those containing mainly calcium sulphate1 which is only precipitated at the high temperatures found in the boiler itself1 #cjj degrees ,fahrenheit or more4 ,the scale of hardness is an arbitrary one1 based on the number of grains of solids per gallon and waters may be classed on such a basis as follows3 #a-aj grain per gallon1 soft water2 #aj-bj grain per gallon1 moderately hard water2 above #be grains per gallon1 very hard water4 ,alkalinity is a general term used for waters containing compounds with the power of neutralizing acids4 ,causticity1 as used in water treatment1 is a term coined by ,a4 ,mc,gill1 indicating the presence of an excess of lime added during treatment4 ,though such presence would also indicate alkalinity1 the term is arbitrarily used to apply to those hydrates whose presence is indicated by phenolphthalein4 ,of the chemical methods of water treatment1 there are three general processes3 #ast4 ,lime ,process4 ,the lime process is used for waters containing bicarbonates of lime and magnesia4 ,slacked lime in solution1 as lime water1 is the reagent used4 ,this combines with the carbonic acid which is present1 either free or as carbonates1 to form an insoluble monocarbonate of lime4 ,the soluble bicarbonates of lime and magnesia1 losing their carbonic acid1 thereby become insoluble and precipitate4 #bnd4 ,soda ,process4 ,the soda process is used for waters containing sulphates of lime and magnesia4 ,carbonate of soda and hydrate of soda 7caustic soda7 are used either alone or together as the reagents4 ,carbonate of soda1 added to water containing little or no carbonic acid or bicarbonates1 decomposes the sulphates to form insoluble carbonate of lime or magnesia which precipitate1 the neutral soda remaining in solution4 ,if free carbonic acid or bicarbonates are present1 bicarbonate of lime is formed and remains in solution1 though under the action of heat1 the carbon dioxide will be driven off and insoluble monocarbonates will be formed4 ,caustic soda used in this process causes a more energetic action1 it being presumed that the caustic soda absorbs the carbonic acid1 becomes carbonate of soda and acts as above4 #crd4 ,lime and ,soda ,process4 ,this process1 which is the combination of the first two1 is by far the most generally used in water purification4 ,such a method is used where sulphates of lime and magnesia are contained in the water1 together with such quantity of carbonic acid or bicarbonates as to impair the action of the soda4 ,sufficient soda is used to break down the sulphates of lime and magnesia and as much lime added as is required to absorb the carbonic acid not taken up in the soda reaction4 ,all of the apparatus for effecting such treatment of feed waters is approximately the same in its chemical action1 the numerous systems differing in the methods of introduction and handling of the reagents4 ,the methods of testing water treated by an apparatus of this description follow4 ,when properly treated1 alkalinity1 hardness and causticity should be in the approximate relation of #f1 #e and #d4 ,when too much lime is used in the treatment1 the causticity in the purified water1 as indicated by the acid test1 will be nearly equal to the alkalinity4 ,if too little lime is used1 the causticity will fall to approximately half the alkalinity4 ,the hardness should not be in excess of two points less than the alkalinity4 ,where too great a quantity of soda is used1 the hardness is lowered and the alkalinity raised4 ,if too little soda1 the hardness is raised and the alkalinity lowered4 ,alkalinity and causticity are tested with a standard solution of sulphuric acid4 ,a standard soap solution is used for testing for hardness and a silver nitrate solution may also be used for determining whether an excess of lime has been used in the treatment4 ,alkalinity3 ,to #ej cubic centimeters of treated water1 to which there has been added sufficient methylorange to color it1 add the acid solution1 drop by drop1 until the mixture is on the point of turning red4 ,as the acid solution is first added1 the red color1 which shows quickly1 disappears on shaking the mixture1 and this color disappears more slowly as the critical point is approached4 ,one-tenth cubic centimeter of the standard acid solution corresponds to one degree of alkalinity4 ,illustration3 #bfdj ,horse-power ,installation of ,babcock ,wilcox ,boilers at the ,botany ,worsted ,mills1 ,passaic1 ,n4 ,j4 ,causticity3 ,to #ej cubic centimeters of treated water1 to which there has been added one drop of phenolphthalein dissolved in alcohol to give the water a pinkish color1 add the acid solution1 drop by drop1 shaking after each addition1 until the color entirely disappears4 ,one-tenth cubic centimeter of acid solution corresponds to one degree of causticity4 ,the alkalinity may be determined from the same sample tested for causticity by the coloring with methylorange and adding the acid until the sample is on the point of turning red4 ,the total acid added in determining both causticity and alkalinity in this case is the measure of the alkalinity4 ,hardness3 #ajj cubic centimeters of the treated water is used for this test1 one cubic centimeter of the soap solution corresponding to one degree of hardness4 ,the soap solution is added a very little at a time and the whole violently shaken4 ,enough of the solution must be added to make a permanent lather or foam1 that is1 the soap bubbles must not disappear after the shaking is stopped4 ,excess of lime as determined by nitrate of silver3 ,if there is an excess of lime used in the treatment1 a sample will become a dark brown by the addition of a small quantity of silver nitrate1 otherwise a milky white solution will be formed4 ,combined ,heat and ,chemical ,treatment3 ,heat is used in many systems of feed treatment apparatus as an adjunct to the chemical process4 ,heat alone will remove temporary hardness by the precipitation of carbonates of lime and magnesia and1 when used in connection with the chemical process1 leaves only the permanent hardness or the sulphates of lime to be taken care of by chemical treatment4 ,,table #af ,,reagents ,,required ,,in ,,lime ,,and ,,soda ,,process ,,for ,,treating #ajjj ,u4 ,s4 ,,gallons ,,of ,,water ,,per ,,grain ,,per ,,gallon ,,of ,,contained ,,impurities#af ---------------------------------------- ----- ,lime#ag ,soda#ah ,pounds ,pounds ---------------------------------------- ----- ,calcium ,carbonate #j4jih 444 ,calcium ,sulphate 444 #j4abd ,calcium ,chloride 444 #j4aea ,calcium ,nitrate 444 #j4ajd ,magnesium ,carbonate #j4bcd 444 ,magnesium ,sulphate #j4jgi #j4ada ,magnesium ,chloride #j4ajc #j4agg ,magnesium ,nitrate #j4jfg #j4aae ,ferrous ,carbonate #j4afi 444 ,ferrous ,sulphate #j4jgj #j4aaj ,ferric ,sulphate #j4jgd #j4abf ,aluminum ,sulphate #j4jhg #j4adg ,free ,sulphuric ,acid #j4ajj #j4aga ,sodium ,carbonate #j4jic 444 ,free ,carbon ,dioxide #j4bbc 444 ,hydrogen ,sulphite #j4bhh 444 ---------------------------------------- ----- ,the chemicals used in the ordinary lime and soda process of feed water treatment are common lime and soda4 ,the efficiency of such apparatus will depend wholly upon the amount and character of the impurities in the water to be treated4 ,table #af gives the amount of lime and soda required per #ajjj gallons for each grain per gallon of the various impurities found in the water4 ,this table is based on lime containing #ij per cent calcium oxide and soda containing #eh per cent sodium oxide1 which correspond to the commercial quality ordinarily purchasable4 ,from this table and the cost of the lime and soda1 the cost of treating any water per #ajjj gallons may be readily computed4 ,less ,usual ,reagents--,barium hydrate is sometimes used to reduce permanent hardness or the calcium sulphate component4 ,until recently1 the high cost of barium hydrate has rendered its use prohibitive but at the present it is obtained as a by-product in cement manufacture and it may be purchased at a more reasonable figure than heretofore4 ,it acts directly on the soluble sulphates to form barium sulphate which is insoluble and may be precipitated4 ,where this reagent is used1 it is desirable that the reaction be allowed to take place outside of the boiler1 though there are certain cases where its internal use is permissible4 ,barium carbonate is sometimes used in removing calcium sulphate1 the products of the reaction being barium sulphate and calcium carbonate1 both of which are insoluble and may be precipitated4 ,as barium carbonate in itself is insoluble1 it cannot be added to water as a solution and its use should1 therefore1 be confined to treatment outside of the boiler4 ,silicate of soda will precipitate calcium carbonate with the formation of a gelatinous silicate of lime and carbonate of soda4 ,if calcium sulphate is also present1 carbonate of soda is formed in the above reaction1 which in turn will break down the sulphate4 ,oxalate of soda is an expensive but efficient reagent which forms a precipitate of calcium oxalate of a particularly insoluble nature4 ,alum and iron alum will act as efficient coagulents where organic matter is present in the water4 ,iron alum has not only this property but also that of reducing oil discharged from surface condensers to a condition in which it may be readily removed by filtration4 ,corrosion--,where there is a corrosive action because of the presence of acid in the water or of oil containing fatty acids which will decompose and cause pitting wherever the sludge can find a resting place1 it may be overcome by the neutralization of the water by carbonate of soda4 ,such neutralization should be carried to the point where the water will just turn red litmus paper blue4 ,as a preventative of such action arising from the presence of the oil1 only the highest grades of hydrocarbon oils should be used4 ,acidity will occur where sea water is present in a boiler4 ,there is the possibility of such an occurrence in marine practice and in stationary plants using sea water for condensing1 due to leaky condenser tubes1 priming in the evaporators1 etc4 ,such acidity is caused through the dissociation of magnesium chloride into hydrochloride acid and magnesia under high temperatures4 ,the acid in contact with the metal forms an iron salt which immediately upon its formation is neutralized by the free magnesia in the water1 thereby precipitating iron oxide and reforming magnesium chloride4 ,the preventive for corrosion arising from such acidity is the keeping tight of the condenser4 ,where it is unavoidable that some sea water should find its way into a boiler1 the acidity resulting should be neutralized by soda ash4 ,this will convert the magnesium chloride into magnesium carbonate and sodium chloride1 neither of which is corrosive but both of which are scale-forming4 ,the presence of air in the feed water which is sucked in by the feed pump is a well recognized cause of corrosion4 ,air bubbles form below the water line and attack the metal of the boiler1 the oxygen of the air causing oxidization of the boiler metal and the formation of rust4 ,the particle of rust thus formed is swept away by the circulation or is dislodged by expansion and the minute pit thus left forms an ideal resting place for other air bubbles and the continuation of the oxidization process4 ,the prevention is1 of course1 the removing of the air from the feed water4 ,in marine practice1 where there has been experienced the most difficulty from this source1 it has been found to be advantageous to pump the water from the hot well to a filter tank placed above the feed pump suction valves4 ,in this way the air is liberated from the surface of the tank and a head is assured for the suction end of the pump4 ,in this same class of work1 the corrosive action of air is reduced by introducing the feed through a spray nozzle into the steam space above the water line4 ,galvanic action1 resulting in the eating away of the boiler metal through electrolysis was formerly considered practically the sole cause of corrosion4 ,but little is known of such action aside from the fact that it does take place in certain instances4 ,the means adopted as a remedy is usually the installation of zinc plates within the boiler1 which must have positive metallic contact with the boiler metal4 ,in this way1 local electrolytic effects are overcome by a still greater electrolytic action at the expense of the more positive zinc4 ,the positive contact necessary is difficult to maintain and it is questionable just what efficacy such plates have except for a short period after their installation when the contact is known to be positive4 ,aside from protection from such electrolytic action1 however1 the zinc plates have a distinct use where there is the liability of air in the feed1 as they offer a substance much more readily oxidized by such air than the metal of the boiler4 ,foaming--,where foaming is caused by organic matter in suspension1 it may be largely overcome by filtration or by the use of a coagulent in connection with filtration1 the latter combination having come recently into considerable favor4 ,alum1 or potash alum1 and iron alum1 which in reality contains no alumina and should rather be called potassia-ferric1 are the coagulents generally used in connection with filtration4 ,such matter as is not removed by filtration may1 under certain conditions1 be handled by surface blowing4 ,in some instances1 settling tanks are used for the removal of matter in suspension1 but where large quantities of water are required1 filtration is ordinarily substituted on account of the time element and the large area necessary in settling tanks4 ,where foaming occurs as the result of overtreatment of the feed water1 the obvious remedy is a change in such treatment4 ,priming--,where priming is caused by excessive concentration of salts within a boiler1 it may be overcome largely by frequent blowing down4 ,the degree of concentration allowable before priming will take place varies widely with conditions of operation and may be definitely determined only by experience with each individual set of conditions4 ,it is the presence of the salts that cause priming that may result in the absolute unfitness of water for boiler feed purposes4 ,where these salts exist in such quantities that the amount of blowing down necessary to keep the degree of concentration below the priming point results in excessive losses1 the only remedy is the securing of another supply of feed1 and the results will warrant the change almost regardless of the expense4 ,in some few instances1 the impurities may be taken care of by some method of water treatment but such water should be submitted to an authority on the subject before any treatment apparatus is installed4 ,illustration3 #cjjj ,horse-power ,installation of ,cross ,drum ,babcock ,wilcox ,boilers and ,superheaters ,equipped with ,babcock ,wilcox ,chain ,grate ,stokers at the ,washington ,terminal ,co41 ,washington1 ,d4 ,c4 ,boiler ,compounds--,the method of treatment of feed water by far the most generally used is by the use of some of the so-called boiler compounds4 ,there are many reliable concerns handling such compounds who unquestionably secure the promised results1 but there is a great tendency toward looking on the compound as a cure all for any water difficulties and care should be taken to deal only with reputable concerns4 ,the composition of these compounds is almost invariably based on soda with certain tannic substances and in some instances a gelatinous substance which is presumed to encircle scale particles and prevent their adhering to the boiler surfaces4 ,the action of these compounds is ordinarily to reduce the calcium sulphate in the water by means of carbonate of soda and to precipitate it as a muddy form of calcium carbonate which may be blown off4 ,the tannic compounds are used in connection with the soda with the idea of introducing organic matter into any scale already formed4 ,when it has penetrated to the boiler metal1 decomposition of the scale sets in1 causing a disruptive effect which breaks the scale from the metal sometimes in large slabs4 ,it is this effect of boiler compounds that is to be most carefully guarded against or inevitable trouble will result from the presence of loose scale with the consequent danger of tube losses through burning4 ,when proper care is taken to suit the compound to the water in use1 the results secured are fairly effective4 ,in general1 however1 the use of compounds may only be recommended for the prevention of scale rather than with the view to removing scale which has already formed1 that is1 the compounds should be introduced with the feed water only when the boiler has been thoroughly cleaned4 ,,feed ,,water ,,heating ,,and ,,methods ,,of ,,feeding ,before water fed into a boiler can be converted into steam1 it must be first heated to a temperature corresponding to the pressure within the boiler4 ,steam at #afj pounds gauge pressure has a temperature of approximately #cga degrees ,fahrenheit4 ,if water is fed to the boiler at #fj degrees ,fahrenheit1 each pound must have #caa ,b4 t4 u4 added to it to increase its temperature #cga degrees1 which increase must take place before the water can be converted into steam4 ,as it requires #aafg4h ,b4 t4 u4 to raise one pound of water from #fj to #cga degrees and to convert it into steam at #afj pounds gauge pressure1 the #caa degrees required simply to raise the temperature of the water from #fj to #cga degrees will be approximately #bg per cent of the total4 ,if1 therefore1 the temperature of the water can be increased from #fj to #cga degrees before it is introduced into a boiler by the utilization of heat from some source that would otherwise be wasted1 there will be a saving in the fuel required of #caa #aafg4h #bg per cent1 and there will be a net saving1 provided the cost of maintaining and operating the apparatus for securing this saving is less than the value of the heat thus saved4 ,the saving in the fuel due to the heating of feed water by means of heat that would otherwise be wasted may be computed from the formula3 #ajj 7t - ti7 ,fuel saving per cent --------------- 7#a7 ,h #cb - ti where1 t temperature of feed water after heating1 ti temperature of feed water before heating1 and ,h total heat above #cb degrees per pound of steam at the boiler pressure4 ,values of ,h may be found in ,table #bc4 ,table #ag has been computed from this formula to show the fuel saving under the conditions assumed with the boiler operating at #ahj pounds gauge pressure4 ,,table #ag ,,saving ,,in ,,fuel1 ,,in ,,per ,,cent1 ,,by ,,heating ,,feed ,,water ,,gauge ,,pressure #ahj ,,pounds ---------------------------------------- ------------ ,initial ,final ,temperature--,degrees ,fahrenheit ,temperature---------------------------- ------- ,fahrenheit #abj #adj #afj #ahj #bjj #bej #cjj ---------------------------------------- ------ #cb #g4ce #i4jbaj4fiab4cfad4jdah4bjbb4ch #ce #g4ab #h4giaj4dfab4adac4hbah4jjbb4ah #dj #f4gb #h4daaj4jiaa4ggac4deag4feba4hf #de #f4cc #h4jb #i4gaaa4djac4jhag4cjba4eb #ej #e4ic #g4fc #i4cbaa4jbab4gbaf4ieba4ai #ee #e4ec #g4bd #h4idaj4fdab4cdaf4fjbj4hf #fj #e4ac #f4hd #h4eeaj4bgaa4igaf4bdbj4eb #fe #d4gb #f4dd #h4af #i4hgaa4eiae4hhbj4ah #gj #d4ca #f4jd #g4gg #i4dhaa4baae4ebai4hc #ge #c4ij #e4fd #g4cf #i4jiaj4hbae4afai4dh #hj #c4dh #e4bb #f4if #h4gjaj4ddad4giai4ac #he #c4jf #d4hj #f4ee #h4cjaj4jead4daah4gh #ij #b4fc #d4ci #f4ad #g4hi #i4fead4jdah4dc #ie #b4bj #c4ig #e4gc #g4di #i4beac4ffah4jg #ajj #a4gg #c4ed #e4ca #g4jh #h4heac4bhag4gj #aaj 4#hi #b4fh #d4dg #f4be #h4jdab4ejaf4ig #abj 4#jj #a4hj #c4fa #e4da #g4baaa4gaaf4bb #acj 4#ia #b4gc #d4ee #f4cgaj4iaae4df #adj 4#jj #a4hd #c4fg #e4eaaj4jiad4fh #aej 4#ic #b4gh #d4fc #i4bfac4hi #afj 4#jj #a4hg #c4gd #h4daac4ji #agj 4#id #b4hc #g4eeab4bg #ahj 4#jj #a4ia #f4fgaa4dc #aij 4#if #e4ggaj4eh #bjj 4#jj #d4hf #i4ga #baj #c4ib #h4hb ---------------------------------------- ------ ,besides the saving in fuel effected by the use of feed water heaters1 other advantages are secured4 ,the time required for the conversion of water into steam is diminished and the steam capacity of the boiler thereby increased4 ,further1 the feeding of cold water into a boiler has a tendency toward the setting up of temperature strains1 which are diminished in proportion as the temperature of the feed approaches that of the steam4 ,an important additional advantage of heating feed water is that in certain types of heaters a large portion of the scale forming ingredients are precipitated before entering the boiler1 with a consequent saving in cleaning and losses through decreased efficiency and capacity4 ,in general1 feed water heaters may be divided into closed heaters1 open heaters and economizers2 the first two depend for their heat upon exhaust1 or in some cases live steam1 while the last class utilizes the heat of the waste flue gases to secure the same result4 ,the question of the type of apparatus to be installed is dependent upon the conditions attached to each individual case4 ,in closed heaters the feed water and the exhaust steam do not come into actual contact with each other4 ,either the steam or the water passes through tubes surrounded by the other medium1 as the heater is of the steam-tube or water-tube type4 ,a closed heater is best suited for water free from scale-forming matter1 as such matter soon clogs the passages4 ,cleaning such heaters is costly and the efficiency drops off rapidly as scale forms4 ,a closed heater is not advisable where the engines work intermittently1 as is the case with mine hoisting engines4 ,in this class of work the frequent coolings between operating periods and the sudden heatings when operation commences will tend to loosen the tubes or even pull them apart4 ,for this reason1 an open heater1 or economizer1 will give more satisfactory service with intermittently operating apparatus4 ,open heaters are best suited for waters containing scale-forming matter4 ,much of the temporary hardness may be precipitated in the heater and the sediment easily removed4 ,such heaters are frequently used with a reagent for precipitating permanent hardness in the combined heat and chemical treatment of feed water4 ,the so-called live steam purifiers are open heaters1 the water being raised to the boiling temperature and the carbonates and a portion of the sulphates being precipitated4 ,the disadvantage of this class of apparatus is that some of the sulphates remain in solution to be precipitated as scale when concentrated in the boiler4 ,sufficient concentration to have such an effect1 however1 may often be prevented by frequent blowing down4 ,economizers find their largest field where the design of the boiler is such that the maximum possible amount of heat is not extracted from the gases of combustion4 ,the more wasteful the boiler1 the greater the saving effected by the use of the economizer1 and it is sometimes possible to raise the temperature of the feed water to that of high pressure steam by the installation of such an apparatus1 the saving amounting in some cases to as much as #bj per cent4 ,the fuel used bears directly on the question of the advisability of an economizer installation1 for when oil is the fuel a boiler efficiency of #hj per cent or over is frequently realized1 an efficiency which would leave a small opportunity for a commercial gain through the addition of an economizer4 ,from the standpoint of space requirements1 economizers are at a disadvantage in that they are bulky and require a considerable increase over space occupied by a heater of the exhaust type4 ,they also require additional brickwork or a metal casing1 which increases the cost4 ,sometimes1 too1 the frictional resistance of the gases through an economizer make its adaptability questionable because of the draft conditions4 ,when figuring the net return on economizer investment1 all of these factors must be considered4 ,when the feed water is such that scale will quickly encrust the economizer and throw it out of service for cleaning during an excessive portion of the time1 it will be necessary to purify water before introducing it into an economizer to make it earn a profit on the investment4 ,from the foregoing1 it is clearly indicated that it is impossible to make a definite statement as to the relative saving by heating feed water in any of the three types4 ,each case must be worked out independently and a decision can be reached only after an exhaustive study of all the conditions affecting the case1 including the time the plant will be in service and probable growth of the plant4 ,when1 as a result of such study1 the possible methods for handling the problem have been determined1 the solution of the best apparatus can be made easily by the balancing of the saving possible by each method against its first cost1 depreciation1 maintenance and cost of operation4 ,feeding of ,water--,the choice of methods to be used in introducing feed water into a boiler lies between an injector and a pump4 ,in most plants1 an injector would not be economical1 as the water fed by such means must be cold1 a fact which makes impossible the use of a heater before the water enters the injector4 ,such a heater might be installed between the injector and the boiler but as heat is added to the water in the injector1 the heater could not properly fulfill its function4 ,,table #ah ,,comparison ,,of ,,pumps ,,and ,,injectors ,method of ,supplying ,feed-water to ,boiler ,relative amount of ,saving of fuel over ,temperature of feed-water as coal required per the amount required delivered to the pump or to unit of time1 the when the boiler is injector1 #fj degrees ,fahren- amount for a direct- fed by a direct- heit4 ,rate of evaporation of acting pump1 feeding acting pump without boiler1 to pounds of water water at #fj degrees heater per pound of coal from and without a heater1 ,per ,cent at #bab degrees ,fahrenheit being taken as unity ,direct-acting ,pump feeding water at #fj degrees without a heater #a4jjj 4#j ,injector feeding water at #aej degrees without a heater 4#ihe #a4e ,injector feeding through a heater in which the water is heated from #aej to #bjj degrees 4#ich #f4b ,direct-acting ,pump feeding water through a heater in which it is heated from #fj to #bjj degrees 4#hgi #ab4a ,geared ,pump run from the engine1 feeding water through a heater in which it is heated from #fj to #bjj degrees 4#hfh #ac4b ,the injector1 considered only in the light of a combined heater and pump1 is claimed to have a thermal efficiency of #ajj per cent1 since all of the heat in the steam used is returned to the boiler with the water4 ,this claim leads to an erroneous idea4 ,if a pump is used in feeding the water to a boiler and the heat in the exhaust from the pump is imparted to the feed water1 the pump has as high a thermal efficiency as the injector4 ,the pump has the further advantage that it uses so much less steam for the forcing of a given quantity of water into the boiler that it makes possible a greater saving through the use of the exhaust from other auxiliaries for heating the feed1 which exhaust1 if an injector were used1 would be wasted1 as has been pointed out4 ,in locomotive practice1 injectors are used because there is no exhaust steam available for heating the feed1 this being utilized in producing a forced draft1 and because of space requirements4 ,in power plant work1 however1 pumps are universally used for regular operation1 though injectors are sometimes installed as an auxiliary method of feeding4 ,table #ah shows the relative value of injectors1 direct-acting steam pumps and pumps driven from the engine1 the data having been obtained from actual experiment4 ,it will be noted that when feeding cold water direct to the boilers1 the injector has a slightly greater economy but when feeding through a heater1 the pump is by far the more economical4 ,auxiliaries--,it is the general impression that auxiliaries will take less steam if the exhaust is turned into the condensers1 in this way reducing the back pressure4 ,as a matter of fact1 vacuum is rarely registered on an indicator card taken from the cylinders of certain types of auxiliaries unless the exhaust connection is short and without bends1 as long pipes and many angles offset the effect of the condenser4 ,on the other hand1 if the exhaust steam from the auxiliaries can be used for heating the feed water1 all of the latent heat less only the loss due to radiation is returned to the boiler and is saved instead of being lost in the condensing water or wasted with the free exhaust4 ,taking into consideration the plant as a whole1 it would appear that the auxiliary machinery1 under such conditions1 is more efficient than the main engines4 ,illustration3 ,portion of #dafj ,horse-power ,installation of ,babcock ,wilcox ,boilers at the ,prudential ,life ,insurance ,co4 ,building1 ,newark1 ,n4 ,j4 ,,steam ,when a given weight of a perfect gas is compressed or expanded at a constant temperature1 the product of the pressure and volume is a constant4 ,vapors1 which are liquids in aeriform condition1 on the other hand1 can exist only at a definite pressure corresponding to each temperature if in the saturated state1 that is1 the pressure is a function of the temperature only4 ,steam is water vapor1 and at a pressure of1 say1 #aej pounds absolute per square inch saturated steam can exist only at a temperature #ceh degrees ,fahrenheit4 ,hence if the pressure of saturated steam be fixed1 its temperature is also fixed1 and vice versa4 ,saturated steam is water vapor in the condition in which it is generated from water with which it is in contact4 ,or it is steam which is at the maximum pressure and density possible at its temperature4 ,if any change be made in the temperature or pressure of steam1 there will be a corresponding change in its condition4 ,if the pressure be increased or the temperature decreased1 a portion of the steam will be condensed4 ,if the temperature be increased or the pressure decreased1 a portion of the water with which the steam is in contact will be evaporated into steam4 ,steam will remain saturated just so long as it is of the same pressure and temperature as the water with which it can remain in contact without a gain or loss of heat4 ,moreover1 saturated steam cannot have its temperature lowered without a lowering of its pressure1 any loss of heat being made up by the latent heat of such portion as will be condensed4 ,nor can the temperature of saturated steam be increased except when accompanied by a corresponding increase in pressure1 any added heat being expended in the evaporation into steam of a portion of the water with which it is in contact4 ,dry saturated steam contains no water4 ,in some cases1 saturated steam is accompanied by water which is carried along with it1 either in the form of a spray or is blown along the surface of the piping1 and the steam is then said to be wet4 ,the percentage weight of the steam in a mixture of steam and water is called the quality of the steam4 ,thus1 if in a mixture of #ajj pounds of steam and water there is three-quarters of a pound of water1 the quality of the steam will be #ii4be4 ,heat may be added to steam not in contact with water1 such an addition of heat resulting in an increase of temperature and pressure if the volume be kept constant1 or an increase in temperature and volume if the pressure remain constant4 ,steam whose temperature thus exceeds that of saturated steam at a corresponding pressure is said to be superheated and its properties approximate those of a perfect gas4 ,as pointed out in the chapter on heat1 the heat necessary to raise one pound of water from #cb degrees ,fahrenheit to the point of ebullition is called the heat of the liquid4 ,the heat absorbed during ebullition consists of that necessary to dissociate the molecules1 or the inner latent heat1 and that necessary to overcome the resistance to the increase in volume1 or the outer latent heat4 ,these two make up the latent heat of evaporation and the sum of this latent heat of evaporation and the heat of the liquid make the total heat of the steam4 ,these values for various pressures are given in the steam tables1 pages #abb to #abg4 ,the specific volume of saturated steam at any pressure is the volume in cubic feet of one pound of steam at that pressure4 ,the density of saturated steam1 that is1 its weight per cubic foot1 is obviously the reciprocal of the specific volume4 ,this density varies as the #af_/ag power over the ordinary range of pressures used in steam boiler work and may be found by the formula1 ,d 4#jjcjbgp4#ida1 which is correct within #j4ae per cent up to #bej pounds pressure4 ,the relative volume of steam is the ratio of the volume of a given weight to the volume of the same weight of water at #ci4b degrees ,fahrenheit and is equal to the specific volume times #fb4dbg4 ,as vapors are liquids in their gaseous form and the boiling point is the point of change in this condition1 it is clear that this point is dependent upon the pressure under which the liquid exists4 ,this fact is of great practical importance in steam condenser work and in many operations involving boiling in an open vessel1 since in the latter case its altitude will have considerable influence4 ,the relation between altitude and boiling point of water is shown in ,table #ab4 ,the conditions of feed temperature and steam pressure in boiler tests1 fuel performances and the like1 will be found to vary widely in different trials4 ,in order to secure a means for comparison of different trials1 it is necessary to reduce all results to some common basis4 ,the method which has been adopted for the reduction to a comparable basis is to transform the evaporation under actual conditions of steam pressure and feed temperature which exist in the trial to an equivalent evaporation under a set of standard conditions4 ,these standard conditions presuppose a feed water temperature of #bab degrees ,fahrenheit and a steam pressure equal to the normal atmospheric pressure at sea level1 #ad4g pounds absolute4 ,under such conditions steam would be generated at a temperature of #bab degrees1 the temperature corresponding to atmospheric pressure at sea level1 from water at #bab degrees4 ,the weight of water which would be evaporated under the assumed standard conditions by exactly the amount of heat absorbed by the boiler under actual conditions existing in the trial1 is1 therefore1 called the equivalent evaporation from and at #bab degrees4 ,the factor for reducing the weight of water actually converted into steam from the temperature of the feed1 at the steam pressure existing in the trial1 to the equivalent evaporation under standard conditions is called the factor of evaporation4 ,this factor is the ratio of the total heat added to one pound of steam under the standard conditions to the heat added to each pound of steam in heating the water from the temperature of the feed in the trial to the temperature corresponding to the pressure existing in the trial4 ,this heat added is obviously the difference between the total heat of evaporation of the steam at the pressure existing in the trial and the heat of the liquid in the water at the temperature at which it was fed in the trial4 ,to illustrate by an example3 ,in a boiler trial the temperature of the feed water is #fj degrees ,fahrenheit and the pressure under which steam is delivered is #afj4c pounds gauge pressure or #age pounds absolute pressure4 ,the total heat of one pound of steam at #age pounds pressure is #aaie4i ,b4 t4 u4 measured above the standard temperature of #cb degrees ,fahrenheit4 ,but the water fed to the boiler contained #bh4jh ,b4 t4 u4 as the heat of the liquid measured above #cb degrees ,fahrenheit4 ,therefore1 to each pound of steam there has been added #aafg4hb ,b4 t4 u4 ,to evaporate one pound of water under standard conditions would1 on the other hand1 have required but #igj4d ,b4 t4 u41 which1 as described1 is the latent heat of evaporation at #bab degrees ,fahrenheit4 ,expressed differently1 the total heat of one pound of steam at the pressure corresponding to a temperature of #bab degrees is #aaej4d ,b4 t4 u4 ,one pound of water at #bab degrees contains #ahj ,b4 t4 u4 of sensible heat above #cb degrees ,fahrenheit4 ,hence1 under standard conditions1 #aaej4d - #ahj #igj4d ,b4 t4 u4 is added in the changing of one pound of water into steam at atmospheric pressure and a temperature of #bab degrees4 ,this is in effect the definition of the latent heat of evaporation4 ,hence1 if conditions of the trial had been standard1 only #igj4d ,b4 t4 u4 would be required and the ratio of #aafg4hb to #igj4d ,b4 t4 u4 is the ratio determining the factor of evaporation4 ,the factor in the assumed case is #aafg4hb #igj4d #a4bjcd and if the same amount of heat had been absorbed under standard conditions as was absorbed in the trial condition1 #a4bjcd times the amount of steam would have been generated4 ,expressed as a formula for use with any set of conditions1 the factor is1 ,h - h ,f ----- 7#b7 #igj4d ,where ,h the total heat of steam above #cb degrees ,fahrenheit from steam tables1 h sensible heat of feed water above #cb degrees ,fahrenheit from ,table #bb4 ,in the form above1 the factor may be determined with either saturated or superheated steam1 provided that in the latter case values of ,h are available for varying degrees of superheat and pressures4 ,where such values are not available1 the form becomes1 ,h - h s7tsup - tsat7 ,f ---------------------------- 7#c7 #igj4d ,where s mean specific heat of superheated steam at the pressure existing in the trial from saturated steam to the temperature existing in the trial1 tsup final temperature of steam1 tsat temperature of saturated steam1 corresponding to pressure existing1 7tsup - tsat7 degrees of superheat4 ,the specific heat of superheated steam will be taken up later4 ,table #ai gives factors of evaporation for saturated steam boiler trials to cover a large range of conditions4 ,except for the most refined work1 intermediate values may be determined by interpolation4 ,steam gauges indicate the pressure above the atmosphere4 ,as has been pointed out1 the atmospheric pressure changes according to the altitude and the variation in the barometer4 ,hence1 calculations involving the properties of steam are based on absolute pressures1 which are equal to the gauge pressure plus the atmospheric pressure in pounds to the square inch4 ,this latter is generally assumed to be #ad4g pounds per square inch at sea level1 but for other levels it must be determined from the barometric reading at that place4 ,vacuum gauges indicate the difference1 expressed in inches of mercury1 between atmospheric pressure and the pressure within the vessel to which the gauge is attached4 ,for approximate purposes1 #b4jd inches height of mercury may be considered equal to a pressure of one pound per square inch at the ordinary temperatures at which mercury gauges are used4 ,hence for any reading of the vacuum gauge in inches1 ,g1 the absolute pressure for any barometer reading in inches1 ,b1 will be 7,b - ,g7 #b4jd4 ,if the barometer is #cj inches measured at ordinary temperatures and not corrected to #cb degrees ,fahrenheit and the vacuum gauge #bd inches1 the absolute pressure will be 7#cj - #bd7 #b4jd #b4i pounds per square inch4 ,,table #ai ,,factors ,,of ,,evaporation ,,calculated ,,from ,,marks ,,and ,,davis ,,tables ,feed ,temp- erature ,degrees ,steam ,pressure by ,gauge ,fahren- heit #ej #fj #gj #hj #ij #ajj #aaj #cb #a4badc #a4bagj #a4baid #a4bbae #a4bbcc #a4bbcc #a4bbfe #dj #a4bjfj #a4bjhg #a4baaa #a4baca #a4baej #a4bafh #a4baha #ej #a4aieg #a4aihd #a4bjjh #a4bjbh #a4bjdg #a4bjfe #a4bjgi #fj #a4ahed #a4ahha #a4aije #a4aibe #a4aidd #a4aifa #a4aigf #gj #a4agej #a4aggh #a4ahjb #a4ahbb #a4ahda #a4ahei #a4ahgc #hj #a4afdi #a4afge #a4afii #a4agbj #a4agch #a4agef #a4aggj #ij #a4aede #a4aegb #a4aeif #a4afag #a4afcf #a4afec #a4affh #ajj #a4addc #a4adgj #a4adic #a4aead #a4aecc #a4aeej #a4aefe #aaj #a4acdj #a4acfg #a4acia #a4adaa #a4adcj #a4addh #a4adfb #abj #a4abcg #a4abfd #a4abhh #a4acji #a4acbg #a4acde #a4acei #acj #a4aacd #a4aafa #a4aahe #a4abjf #a4abbe #a4abdb #a4abeg #adj #a4ajca #a4ajeh #a4ajhb #a4aajc #a4aabb #a4aaci #a4aaed #aej #a4jibh #a4jiee #a4jigi #a4ajjj #a4ajai #a4ajcf #a4ajea #afj #a4jhbe #a4jheb #a4jhgf #a4jhig #a4jiaf #a4jicc #a4jidh #agj #a4jgbb #a4jgdi #a4jggc #a4jgid #a4jhac #a4jhcj #a4jhde #ahj #a4jfai #a4jfdf #a4jfgj #a4jfia #a4jgji #a4jgbg #a4jgda #aij #a4jeaf #a4jedc #a4jefg #a4jehg #a4jfjf #a4jfbd #a4jfch #bjj #a4jdab #a4jdci #a4jdfc #a4jdhd #a4jejc #a4jebj #a4jece #baj #a4jcji #a4jccf #a4jcfj #a4jchj #a4jcii #a4jdag #a4jdcb ,feed ,temp- erature ,degrees ,steam ,pressure by ,gauge ,fahren- heit #abj #acj #adj #aej #afj #agj #ahj #cb #a4bbhj #a4bbib #a4bcjd #a4bcad #a4bcbc #a4bccc #a4bcdb #dj #a4baif #a4bbji #a4bbba #a4bbca #a4bbda #a4bbej #a4bbei #ej #a4bjic #a4bajf #a4baag #a4babh #a4bacg #a4badg #a4baef #fj #a4aiij #a4bjjc #a4bjad #a4bjbe #a4bjcd #a4bjdd #a4bjec #gj #a4ahhg #a4aijj #a4aiaa #a4aibb #a4aica #a4aida #a4aiej #hj #a4aghe #a4agig #a4ahji #a4ahai #a4ahbh #a4ahch #a4ahdg #ij #a4afhb #a4afie #a4agjf #a4agag #a4agbe #a4agce #a4agdd #ajj #a4aegi #a4aeib #a4afjc #a4afad #a4afbc #a4afcc #a4afdb #aaj #a4adgg #a4adhi #a4aejj #a4aeaa #a4aebj #a4aecj #a4aeci #abj #a4acgd #a4achf #a4acih #a4adjh #a4adah #a4adbg #a4adcf #acj #a4abga #a4abhd #a4abie #a4acje #a4acae #a4acbd #a4accc #adj #a4aafh #a4aaha #a4aaib #a4abjc #a4abab #a4abba #a4abcj #aej #a4ajfe #a4ajgh #a4ajhi #a4ajii #a4aaji #a4aaah #a4aabg #afj #a4jifb #a4jige #a4jihf #a4jiig #a4ajjf #a4ajae #a4ajbd #agj #a4jhei #a4jhgb #a4jhhc #a4jhic #a4jijc #a4jiab #a4jiba #ahj #a4jgef #a4jgfh #a4jghj #a4jgij #a4jhjj #a4jhji #a4jhah #aij #a4jfec #a4jffe #a4jfgf #a4jfhg #a4jfif #a4jgjf #a4jgae #bjj #a4jedi #a4jefb #a4jegc #a4jehd #a4jeic #a4jfjb #a4jfaa #baj #a4jddf #a4jdeh #a4jdfi #a4jdhj #a4jdhi #a4jdii #a4jejh ,feed ,temp- erature ,degrees ,steam ,pressure by ,gauge ,fahren- heit #aij #bjj #baj #bbj #bcj #bdj #bej #cb #a4bcej #a4bceg #a4bcfd #a4bcgb #a4bcgh #a4bchd #a4bcij #dj #a4bbfg #a4bbgd #a4bbhb #a4bbhi #a4bbie #a4bcja #a4bcjg #ej #a4bafd #a4baga #a4bagh #a4bahf #a4baib #a4baih #a4bbjd #fj #a4bjfa #a4bjfh #a4bjge #a4bjhc #a4bjhi #a4bjie #a4baja #gj #a4aieh #a4aife #a4aigb #a4aihj #a4aihf #a4aiib #a4aiih #hj #a4ahee #a4ahfc #a4ahfi #a4ahgg #a4ahhc #a4ahhi #a4ahie #ij #a4agej #a4agfj #a4agff #a4aggd #a4aghj #a4aghf #a4agib #ajj #a4afej #a4afeg #a4affd #a4afga #a4afgh #a4afhd #a4afij #aaj #a4aedg #a4aeed #a4aefb #a4aefi #a4aege #a4aeha #a4aehg #abj #a4addd #a4adeb #a4adei #a4adff #a4adgb #a4adgh #a4adhd #acj #a4acda #a4acdi #a4acef #a4acfc #a4acfi #a4acge #a4acha #adj #a4abci #a4abdf #a4abec #a4abfj #a4abff #a4abgb #a4abgh #aej #a4aacf #a4aadc #a4aaej #a4aaeg #a4aafc #a4aafi #a4aagf #afj #a4ajcc #a4ajdj #a4ajdg #a4ajed #a4ajfj #a4ajff #a4ajgc #agj #a4jicj #a4jicg #a4jidd #a4jiea #a4jieg #a4jifc #a4jifi #ahj #a4jhbf #a4jhcd #a4jhda #a4jhdh #a4jhed #a4jhfj #a4jhff #aij #a4jgbc #a4jgcj #a4jgcg #a4jgde #a4jgea #a4jgeg #a4jgfc #bjj #a4jfbj #a4jfbg #a4jfcd #a4jfda #a4jfdg #a4jfec #a4jffj #baj #a4jeaf #a4jebc #a4jecj #a4jech #a4jedd #a4jeej #a4jeef ,the temperature1 pressure and other properties of steam for varying amounts of vacuum and the pressure above vacuum corresponding to each inch of reading of the vacuum gauge are given in ,table #bj4 ,,table #bj ,,properties ,,of ,,saturated ,,steam ,,for ,,varying ,,amounts ,,of ,,vacuum ,,calculated ,,from ,,marks ,,and ,,davis ,,tables ,heat of ,latent ,total ,temp- the ,liquid ,heat ,heat erature ,above ,above ,above ,density or ,absolute ,degrees #cb ,de- #cb ,de- #cb ,de- ,weight per ,vacuum ,pressure ,fahren- grees grees grees ,cubic ,foot ,ins4 ,hg4 ,pounds heit ,b4 t4 u4 ,b4 t4 u4,b4 t4 u4 ,pounds #bi4e 4#bjg #ed4a #bb4ah #ajfa4j #ajhc4b #j4jjjfgh #bi 4#deb #gf4f #dd4fd #ajdh4g #ajic4c #j4jjadae #bh4e 4#fih #ij4a #eh4ji #ajda4a #ajii4b #j4jjbacg #bh 4#idd #ii4i #fg4hg #ajce4f #aajc4e #j4jjbhdc #bg #a4dd #aab4e #hj4d #ajbh4f #aaji4j #j4jjdba #bf #a4ic #abd4e #ib4c #ajbb4j #aaad4c #j4jjegg #be #b4db #acb4f #ajj4e #ajag4c #aaag4h #j4jjfhi #bd #b4ia #adj4a #ajh4j #ajac4a #aaba4a #j4jjhba #bb #c4hi #aea4g #aai4f #ajjf4d #aabf4j #j4jajgh #bj #d4hg #afa4a #abh4i #ajja4j #aabi4i #j4jacca #ah #e4hf #afh4i #acf4h #iif4d #aacc4b #j4jaeha #af #f4hd #age4h #adc4f #iib4d #aacf4j #j4jahbg #ad #g4hb #aha4h #adi4g #ihh4h #aach4e #j4jbjgj #ab #h4hj #ahg4b #aee4a #ihe4f #aadj4g #j4jbcab #aj #i4gi #aib4b #afj4a #ihb4f #aadb4g #j4jbeed #e #ab4bd #bjb4i #agj4h #igf4j #aadf4h #j4jcadh ,from the steam tables1 the condensed ,table #ba of the properties of steam at different pressures may be constructed4 ,from such a table there may be drawn the following conclusions4 ,,table #ba ,,variation ,,in ,,properties ,,of ,,saturated ,,steam ,,with ,,pressure ,pressure ,temperature ,heat of ,latent ,total ,pounds ,degrees ,liquid ,heat ,heat ,absolute ,fahrenheit ,b4 t4 u4 ,b4 t4 u4,b4 t4 u4 #ad4g #bab4j #ahj4j #igj4d #aaej4d #bj4j #bbh4j #aif4a #ifj4j #aaef4b #ajj4j #cbg4h #bih4c #hhh4j #aahf4c #cjj4j #dag4e #cib4g #haa4c #abjd4a ,as the pressure and temperature increase1 the latent heat decreases4 ,this decrease1 however1 is less rapid than the corresponding increase in the heat of the liquid and hence the total heat increases with an increase in the pressure and temperature4 ,the percentage increase in the total heat is small1 being #j4e1 #c4a1 and #d4g per cent for #bj1 #ajj1 and #cjj pounds absolute pressure respectively above the total heat in one pound of steam at #ad4g pounds absolute4 ,the temperatures1 on the other hand1 increase at the rates of #g4e1 #ed4f1 and #if4i per cent4 ,the efficiency of a perfect steam engine is proportional to the expression 7t - t#a7_/t in which t and t#a are the absolute temperatures of the saturated steam at admission and exhaust respectively4 ,while actual engines only approximate the ideal engine in efficiency1 yet they follow the same general law4 ,since the exhaust temperature cannot be lowered beyond present practice1 it follows that the only available method of increasing the efficiency is by an increase in the temperature of the steam at admission4 ,how this may be accomplished by an increase of pressure is clearly shown1 for the increase of fuel necessary to increase the pressure is negligible1 as shown by the total heat1 while the increase in economy1 due to the higher pressure1 will result directly from the rapid increase of the corresponding temperature4 ,,table #bb ,,heat ,,units ,,per ,,pound ,,and ,,weight ,,per ,,cubic ,,foot ,,of ,,water ,,between #cb ,,degrees ,,fahrenheit ,,and #cdj ,,degrees ,,fahrenheit ,temperature,heat ,units ,weight ,degrees per per ,fahrenheit ,pound ,cubic ,foot #cb #j4jj #fb4db #cc #a4ja #fb4db #cd #b4ja #fb4db #ce #c4jb #fb4dc #cf #d4jc #fb4dc #cg #e4jd #fb4dc #ch #f4jd #fb4dc #ci #g4je #fb4dc #dj #h4je #fb4dc #da #i4je #fb4dc #db #aj4jf #fb4dc #dc #aa4jf #fb4dc #dd #ab4jf #fb4dc #de #ac4jg #fb4db #df #ad4jg #fb4db #dg #ae4jg #fb4db #dh #af4jg #fb4db #di #ag4jh #fb4db #ej #ah4jh #fb4db #ea #ai4jh #fb4da #eb #bj4jh #fb4da #ec #ba4jh #fb4da #ed #bb4jh #fb4dj #ee #bc4jh #fb4dj #ef #bd4jh #fb4ci #eg #be4jh #fb4ci #eh #bf4jh #fb4ch #ei #bg4jh #fb4cg #fj #bh4jh #fb4cg #fa #bi4jh #fb4cf #fb #cj4jh #fb4cf #fc #ca4jg #fb4ce #fd #cb4jg #fb4ce #fe #cc4jg #fb4cd #ff #cd4jg #fb4cc #fg #ce4jg #fb4cc #fh #cf4jg #fb4cb #fi #cg4jf #fb4ca #gj #ch4jf #fb4cj #ga #ci4jf #fb4cj #gb #dj4je #fb4bi #gc #da4je #fb4bh #gd #db4je #fb4bg #ge #db4je #fb4bf #gf #dd4jd #fb4bf #gg #de4jd #fb4be #gh #df4jd #fb4bd #gi #dg4jd #fb4bc #hj #dh4jc #fb4bb #ha #di4jc #fb4ba #hb #ej4jc #fb4bj #hc #ea4jb #fb4ai #hd #eb4jb #fb4ah #he #ec4jb #fb4ag #hf #ed4ja #fb4af #hg #ee4ja #fb4ae #hh #ef4ja #fb4ad #hi #eg4jj #fb4ac #ij #eh4jj #fb4ab #ia #ei4jj #fb4aa #ib #fj4jj #fb4ji #ic #fj4ii #fb4jh #id #fa4ii #fb4jg #ie #fb4ii #fb4jf #if #fc4ih #fb4je #ig #fd4ih #fb4jd #ih #fe4ih #fb4jc #ii #ff4ig #fb4jb #ajj #fg4ig #fb4jj #aja #fh4ig #fa4ii #ajb #fi4if #fa4ih #ajc #gj4if #fa4ig #ajd #ga4if #fa4ie #aje #gb4ie #fa4id #ajf #gc4ie #fa4ic #ajg #gd4ie #fa4ia #ajh #ge4ie #fa4ij #aji #gf4id #fa4hh #aaj #gg4id #fa4hf #aaa #gh4id #fa4he #aab #gi4ic #fa4hc #aac #hj4ic #fa4hb #aad #ha4ic #fa4hj #aae #hb4ib #fa4gi #aaf #hc4ib #fa4gg #aag #hd4ib #fa4ge #aah #he4ib #fa4gd #aai #hf4ia #fa4gb #abj #hg4ia #fa4ga #aba #hh4ia #fa4fi #abb #hi4ia #fa4fh #abc #ij4ij #fa4ff #abd #ia4ij #fa4fe #abe #ib4ij #fa4fc #abf #ic4ij #fa4fa #abg #id4hi #fa4ei #abh #ie4hi #fa4eh #abi #if4hi #fa4ef #acj #ig4hi #fa4ee #aca #ih4hi #fa4ec #acb #ii4hh #fa4eb #acc #ajj4hh #fa4ej #acd #aja4hh #fa4di #ace #ajb4hh #fa4dg #acf #ajc4hh #fa4de #acg #ajd4hg #fa4dc #ach #aje4hg #fa4da #aci #ajf4hg #fa4dj 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#aij #aeg1ia #fj4cf #aia #aeh4ia #fj4cc #aib #aei4ia #fj4ca #aic #afj4ia #fj4bi #aid #afa4ib #fj4bg #aie #afb4ib #fj4bd #aif #afc4ib #fj4bb #aig #afd4ic #fj4ai #aih #afe4ic #fj4ag #aii #aff4id #fj4ae #bjj #afg4id #fj4ab #bja #afh4id #fj4aj #bjb #afi4ie #fj4jg #bjc #agj4ie #fj4je #bjd #aga4if #fj4jb #bje #agb4if #fj4jj #bjf #agc4ig #ei4ih #bjg #agd4ig #ei4ie #bjh #age4ih #ei4ic #bji #agf4ih #ei4ij #baj #agg4ii #ei4hh #baa #agh4ii #ei4he #bab #ahj4jj #ei4hc #bac #aha4j #ei4hj #bad #ahb4j #ei4gh #bae #ahc4j #ei4ge #baf #ahd4j #ei4gc #bag #ahe4j #ei4gj #bah #ahf4a #ei4fh #bai #ahg4a #ei4fe #bbj #ahh4a #ei4fc #bba #ahi4a #ei4fj #bbb #aij4a #ei4eh #bbc #aia4a #ei4ee #bbd #aib4a #ei4ec #bbe #aic4a #ei4ej #bbf #aid4a #ei4dh #bbg #aie4b #ei4de #bbh #aif4b #ei4db #bbi #aig4b #ei4dj #bcj #aih4b #ei4cg #bca #aii4b #ei4cd #bcb #bjj4b #ei4cb #bcc #bja4b #ei4bi #bcd #bjb4b #ei4bg #bce #bjc4b #ei4bd #bcf #bjd4b #ei4ba #bcg #bje4c #ei4ai #bch #bjf4c #ei4af #bci #bjg4c #ei4ad #bdj #bjh4c #ei4aa #bda #bji4c #ei4jh #bdb #baj4c #ei4je #bdc #baa4d #ei4jc #bdd #bab4d #ei4jj #bde #bac4d #eh4ig #bdf #bad4d #eh4id #bdg #bae4d #eh4ia #bdh #baf4d #eh4hi #bdi #bag4d #eh4hf #bej #bah4e #eh4hc #bfj #bbh4f #eh4ee #bgj #bch4h #eh4bf #bhj #bdi4j #eg4if #bij #bei4c #eg4fe #cjj #bfi4f #eg4cc #caj #bgi4i #eg4jj #cbj #bij4b #ef4ff #ccj #cjj4f #ef4cj #cdj #caa4j #ee4id ,the gain due to superheat cannot be predicted from the formula for the efficiency of a perfect steam engine given on page #aai4 ,this formula is not applicable in cases where superheat is present since only a relatively small amount of the heat in the steam is imparted at the maximum or superheated temperature4 ,the advantage of the use of high pressure steam may be also indicated by considering the question from the aspect of volume4 ,with an increase of pressure comes a decrease in volume1 thus one pound of saturated steam at #ajj pounds absolute pressure occupies #d4dc cubic feet1 while at #bjj pounds pressure it occupies #b4bi cubic feet4 ,if then1 in separate cylinders of the same dimensions1 one pound of steam at #ajj pounds absolute pressure and one pound at #bjj pounds absolute pressure enter and are allowed to expand to the full volume of each cylinder1 the high-pressure steam1 having more room and a greater range for expansion than the low-pressure steam1 will thus do more work4 ,this increase in the amount of work1 as was the increase in temperature1 is large relative to the additional fuel required as indicated by the total heat4 ,in general1 it may be stated that the fuel required to impart a given amount of heat to a boiler is practically independent of the steam pressure1 since the temperature of the fire is so high as compared with the steam temperature that a variation in the steam temperature does not produce an appreciable effect4 ,the formulae for the algebraic expression of the relation between saturated steam pressures1 temperatures and steam volumes have been up to the present time empirical4 ,these relations have1 however1 been determined by experiment and1 from the experimental data1 tables have been computed which render unnecessary the use of empirical formulae4 ,such formulae may be found in any standard work of thermo-dynamics4 ,the following tables cover all practical cases4 ,table #bb gives the heat units contained in water above #cb degrees ,fahrenheit at different temperatures4 ,table #bc gives the properties of saturated steam for various pressures4 ,table #bd gives the properties of superheated steam at various pressures and temperatures4 ,these tables are based on those computed by ,lionel ,s4 ,marks and ,harvey ,n4 ,davis1 these being generally accepted as being the most correct4 ,,table #bc ,,properties ,,of ,,saturated ,,steam ,,reproduced ,,by ,,permission ,,from ,,marks ,,and ,,davis ,,steam ,,tables ,,and ,,diagrams 7,copyright1 #aiji1 by ,longmans1 ,green ,co47 ,pressure1 ,temper- ,specific ,vol-,heat of ,latent ,heat,total ,heat ,pounds ature 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of #ad1jjj ,horse ,power of ,babcock ,wilcox ,boilers ,,table #bd ,,properties ,,of ,,superheated ,,steam ,,reproduced ,,by ,,permission ,,from ,,marks ,,and ,,davis ,,steam ,,tables ,,and ,,diagrams 7,copyright1 #aiji1 by ,longmans1 ,green ,co47 ,degrees of ,superheat ,pressure ,pounds ,saturated ,absolute ,steam #ej #ajj #aej #bjj #bej #cjj t #afb4c #bab4c #bfb4c #cab4c #cfb4c #dab4c #dfb4c #e v #gc4c #gi4g #he4g #ia4h #ig4h #ajc4h #aji4h h #aacj4e #aaec4e #aagf4d #aaii4e #abbb4e #abde4f #abfh4g t #aic4b #bdc4b #bic4b #cdc4b #cic4b #ddc4b #dic4b #aj v #ch4d #da4e #dd4f #dg4g #ej4g #ec4g #ef4g h #aadc4a #aaff4c #aahi4e #abab4g #abcf4j #abei4c #abhb4e t #bac4j #bfc4j #cac4j #cfc4j #dac4j #dfc4j #eac4j #ae v #bf4bg #bh4dj #cj4df #cb4ej #cd4ec #cf4ef #ch4eh h #aaej4g #aagd4b #aaig4f #abba4j #abdd4d #abfg4g #abia4a t #bbh4j #bgh4j #cbh4j #cgh4j #dbh4j #dgh4j #ebh4j #bj v #bj4jh #ba4fi #bc4be #bd4hj #bf4cc #bg4he #bi4cg h #aaef4b #aagi4i #abjc4e #abbg4a #abej4f #abgd4a #abig4f t #bdj4a 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#abhd4j #acji4j #accc4g #aceh4d t #chh4j #dch4j #dhh4j #ech4j #ehh4j #fch4j #fhh4j #bae v #b4ad #b4cc #b4ea #b4fh #b4hd #c4jj #c4af h #aaii4b #abca4f #abei4j #abhd4f #acji4g #accd4d #acei4a t #chi4i #dci4i #dhi4i #eci4i #ehi4i #fci4i #fhi4i #bbj v #b4ji #b4bh #b4de #b4fb #b4gh #b4id #c4aj h #aaii4f #abcb4b #abei4f #abhe4b #acaj4c #acce4a #acei4h t #cia4i #dda4i #dia4i #eda4i #eia4i #fda4i #fia4i #bbe v #b4je #b4bc #b4dj #b4eg #b4gb #b4hh #c4jc h #aaii4i #abcb4g #abfj4b #abhe4i #acaj4i #acce4g #acfj4c t #cic4h #ddc4h #dic4h #edc4h #eic4h #fdc4h #fic4h #bcj v #b4jj #b4ah #b4ce #b4ea #b4fg #b4hb #b4ig h #abjj4b #abcc4b #abfj4g #abhf4e #acaa4f #accf4c #acfa4j t #cie4f #dde4f #die4f #ede4f #eie4f #fde4f #fie4f #bce v #a4if #b4ad #b4cj #b4df #b4fb #b4gg #b4ia h #abjj4f #abcc4h #abfa4d #abhg4a #acab4b #accg4j #acfa4g t #cig4d #ddg4d #dig4d #edg4d #eig4d #fdg4d #fig4d #bdj v #a4ib #b4ji #b4bf #b4db #b4eg #b4ga #b4he h #abjj4i #abcd4c #abfa4i #abhg4f #acab4h #accg4f #acfb4c t #cii4c #ddi4c #dii4c #edi4c #eii4c #fdi4c #fii4c #bde v #a4hi #b4je #b4bb #b4cg #b4eb #b4ff #b4hj h #abja4b #abcd4h #abfb4e #abhh4b #acac4c #acch4b #acfb4i t #dja4j #dea4j #eja4j #eea4j #fja4j #fea4j #gja4j #bej v #a4he #b4jb #b4ag #b4cc #b4dg #b4fa #b4ge h #abja4e #abce4d #abfc4j #abhh4h #acac4i #acch4h #acfc4e t #djb4h #deb4h #ejb4h #eeb4h #fjb4h #feb4h #gjb4h #bee v #a4ha #a4ih #b4ad #b4bh #b4dc #b4ef #b4gj h #abja4h #abce4i #abfc4f #abhi4c #acad4e #acci4c #acfd4a t ,temperature1 degrees ,fahrenheit4 v ,specific volume1 in cubic feet1 per pound4 h ,total heat from water at #cb degrees1 ,b4 t4 u4 ,graph3 ,temperature of ,steam--,degrees ,fahr4 against ,temperature in ,calorimeter--,degrees ,fahr4 ,fig4 #ae4 ,graphic ,method of ,determining ,moisture ,contained in ,steam from ,calorimeter ,readings ,,moisture ,,in ,,steam ,the presence of moisture in steam causes a loss1 not only in the practical waste of the heat utilized to raise this moisture from the temperature of the feed water to the temperature of the steam1 but also through the increased initial condensation in an engine cylinder and through friction and other actions in a steam turbine4 ,the presence of such moisture also interferes with proper cylinder lubrication1 causes a knocking in the engine and a water hammer in the steam pipes4 ,in steam turbines it will cause erosion of the blades4 ,the percentage by weight of steam in a mixture of steam and water is called the quality of the steam4 ,the apparatus used to determine the moisture content of steam is called a calorimeter though since it may not measure the heat in the steam1 the name is not descriptive of the function of the apparatus4 ,the first form used was the barrel calorimeter1 but the liability of error was so great that its use was abandoned4 ,modern calorimeters are in general of either the throttling or separator type4 ,throttling ,calorimeter--,fig4 #ad shows a typical form of throttling calorimeter4 ,steam is drawn from a vertical main through the sampling nipple1 passes around the first thermometer cup1 then through a one-eighth inch orifice in a disk between two flanges1 and lastly around the second thermometer cup and to the atmosphere4 ,thermometers are inserted in the wells1 which should be filled with mercury or heavy cylinder oil4 ,illustration3 ,fig4 #ad4 ,throttling ,calorimeter and ,sampling ,nozzle ,the instrument and all pipes and fittings leading to it should be thoroughly insulated to diminish radiation losses4 ,care must be taken to prevent the orifice from becoming choked with dirt and to see that no leaks occur4 ,the exhaust pipe should be short to prevent back pressure below the disk4 ,when steam passes through an orifice from a higher to a lower pressure1 as is the case with the throttling calorimeter1 no external work has to be done in overcoming a resistance4 ,hence1 if there is no loss from radiation1 the quantity of heat in the steam will be exactly the same after passing the orifice as before passing4 ,if the higher steam pressure is #afj pounds gauge and the lower pressure that of the atmosphere1 the total heat in a pound of dry steam at the former pressure is #aaie4i ,b4 t4 u4 and at the latter pressure #aaej4d ,b4 t4 u41 a difference of #de4d ,b4 t4 u4 ,as this heat will still exist in the steam at the lower pressure1 since there is no external work done1 its effect must be to superheat the steam4 ,assuming the specific heat of superheated steam to be #j4dg1 each pound passing through will be superheated #de4d_/j4dg #if4f degrees4 ,if1 however1 the steam had contained one per cent of moisture1 it would have contained less heat units per pound than if it were dry4 ,since the latent heat of steam at #afj pounds gauge pressure is #heb4h ,b4 t4 u41 it follows that the one per cent of moisture would have required #h4e ,b4 t4 u4 to evaporate it1 leaving only #de4d - #h4e #cf4i ,b4 t4 u4 available for superheating2 hence1 the superheat would be #cf4i_/j4dg #gh4e degrees1 as against #if4f degrees for dry steam4 ,in a similar manner1 the degree of superheat for other percentages of moisture may be determined4 ,the action of the throttling calorimeter is based upon the foregoing facts1 as shown below4 ,let ,h total heat of one pound of steam at boiler pressure1 ,l latent heat of steam at boiler pressure1 h total heat of steam at reduced pressure after passing orifice1 t#a temperature of saturated steam at the reduced pressure1 t#b temperature of steam after expanding through the orifice in the disc1 #j4dg the specific heat of saturated steam at atmospheric pressure1 x proportion by weight of moisture in steam4 ,the difference in ,b4 t4 u4 in a pound of steam at the boiler pressure and after passing the orifice is the heat available for evaporating the moisture content and superheating the steam4 ,therefore1 ,h - h x,l #j4dg7t#b - t#a7 ,h - h - #j4dg7t#b - t#a7 or x --------------------------- 7#d7 ,l ,almost invariably the lower pressure is taken as that of the atmosphere4 ,under such conditions1 h #aaej4d and t#a #bab degrees4 ,the formula thus becomes3 ,h - #aaej4d - #j4dg7t#b - #bab7 x ------------------------------ 7#e7 ,l ,for practical work it is more convenient to dispense with the upper thermometer in the calorimeter and to measure the pressure in the steam main by an accurate steam pressure gauge4 ,a chart may be used for determining the value of x for approximate work without the necessity for computation4 ,such a chart is shown in ,fig4 #ae and its use is as follows3 ,assume a gauge pressure of #ahj pounds and a thermometer reading of #bie degrees4 ,the intersection of the vertical line from the scale of temperatures as shown by the calorimeter thermometer and the horizontal line from the scale of gauge pressures will indicate directly the per cent of moisture in the steam as read from the diagonal scale4 ,in the present instance1 this per cent is #a4j4 ,sources of ,error in the ,apparatus--,a slight error may arise from the value1 #j4dg1 used as the specific heat of superheated steam at atmospheric pressure4 ,this value1 however is very nearly correct and any error resulting from its use will be negligible4 ,there is ordinarily a larger source of error due to the fact that the stem of the thermometer is not heated to its full length1 to an initial error in the thermometer and to radiation losses4 ,with an ordinary thermometer immersed in the well to the #ajj degrees mark1 the error when registering #cjj degrees would be about #c degrees and the true temperature be #cjc degrees4#ai ,the steam is evidently losing heat through radiation from the moment it enters the sampling nipple4 ,the heat available for evaporating moisture and superheating steam after it has passed through the orifice into the lower pressure will be diminished by just the amount lost through radiation and the value of t#b1 as shown by the calorimeter thermometer1 will1 therefore1 be lower than if there were no such loss4 ,the method of correcting for the thermometer and radiation error recommended by the ,power ,test ,committee of the ,american ,society of ,mechanical ,engineers is by referring the readings as found on the boiler trial to a normal reading of the thermometer4 ,this normal reading is the reading of the lower calorimeter thermometer for dry saturated steam1 and should be determined by attaching the instrument to a horizontal steam pipe in such a way that the sampling nozzle projects upward to near the top of the pipe1 there being no perforations in the nozzle and the steam taken only through its open upper end4 ,the test should be made with the steam in a quiescent state and with the steam pressure maintained as nearly as possible at the pressure observed in the main trial1 the calorimeter thermometer to be the same as was used on the trial or one exactly similar4 ,with a normal reading thus obtained for a pressure approximately the same as existed in the trial1 the true percentage of moisture in the steam1 that is1 with the proper correction made for radiation1 may be calculated as follows3 ,let ,t denote the normal reading for the conditions existing in the trial4 ,the effect of radiation from the instrument as pointed out will be to lower the temperature of the steam at the lower pressure4 ,let x#a represent the proportion of water in the steam which will lower its temperature an amount equal to the loss by radiation4 ,then1 ,h - h - #j4dg7,t - t#a7 x#a ----------------------- ,l ,this amount of moisture1 x#a was not in the steam originally but is the result of condensation in the instrument through radiation4 ,hence1 the true amount of moisture in the steam represented by ,x is the difference between the amount as determined in the trial and that resulting from condensation1 or1 ,x x - x#a ,h - h - #j4dg7t#b - t#a7 ,h - h - #j4dg7,t - t#a7 --------------------------- - ----------------------- ,l ,l #j4dg7,t - t#b7 --------------- 7#f7 ,l ,as ,t and t#b are taken with the same thermometer under the same set of conditions1 any error in the reading of the thermometers will be approximately the same for the temperatures ,t and t#b and the above method therefore corrects for both the radiation and thermometer errors4 ,the theoretical readings for dry steam1 where there are no losses due to radiation1 are obtainable from formula 7#e7 by letting x #j and solving for t#b4 ,the difference between the theoretical reading and the normal reading for no moisture will be the thermometer and radiation correction to be applied in order that the correct reading of t#b may be obtained4 ,for any calorimeter within the range of its ordinary use1 such a thermometer and radiation correction taken from one normal reading is approximately correct for any conditions with the same or a duplicate thermometer4 ,the percentage of moisture in the steam1 corrected for thermometer error and radiation and the correction to be applied to the particular calorimeter used1 would be determined as follows3 ,assume a gauge pressure in the trial to be #ahj pounds and the thermometer reading to be #bie degrees4 ,a normal reading1 taken in the manner described1 gives a value of ,t #cjc degrees2 then1 the percentage of moisture corrected for thermometer error and radiation is1 #j4dg7cjc - #bie7 x ---------------- #hde4j #j4de per cent4 ,the theoretical reading for dry steam will be1 #aaig4g - #aaej4d - #j4dg7t#b - #bab7 #j ------------------------------------ #hde4j t#b #cac degrees4 ,the thermometer and radiation correction to be applied to the instrument used1 therefore over the ordinary range of pressure is ,correction #cac - #cjc #aj degrees ,the chart may be used in the determination of the correct reading of moisture percentage and the permanent radiation correction for the instrument used without computation as follows3 ,assume the same trial pressure1 feed temperature and normal reading as above4 ,if the normal reading is found to be #cjc degrees1 the correction for thermometer and radiation will be the theoretical reading for dry steam as found from the chart1 less this normal reading1 or #aj degrees correction4 ,the correct temperature for the trial in question is1 therefore1 #cje degrees4 ,the moisture corresponding to this temperature and #ahj pounds gauge pressure will be found from the chart to be #j4de per cent4 ,illustration3 ,fig4 #af4 ,compact ,throttling ,calorimeter ,there are many forms of throttling calorimeter1 all of which work upon the same principle4 ,the simplest one is probably that shown in ,fig4 #ad4 ,an extremely convenient and compact design is shown in ,fig4 #af4 ,this calorimeter consists of two concentric metal cylinders screwed to a cap containing a thermometer well4 ,the steam pressure is measured by a gauge placed in the supply pipe or other convenient location4 ,steam passes through the orifice ,a and expands to atmospheric pressure1 its temperature at this pressure being measured by a thermometer placed in the cup ,c4 ,to prevent as far as possible radiation losses1 the annular space between the two cylinders is used as a jacket1 steam being supplied to this space through the hole ,b4 ,the limits of moisture within which the throttling calorimeter will work are1 at sea level1 from #b4hh per cent at #ej pounds gauge pressure and #g4ag per cent moisture at #bej pounds pressure4 ,separating ,calorimeter--,the separating calorimeter mechanically separates the entrained water from the steam and collects it in a reservoir1 where its amount is either indicated by a gauge glass or is drained off and weighed4 ,fig4 #ag shows a calorimeter of this type4 ,the steam passes out of the calorimeter through an orifice of known size so that its total amount can be calculated or it can be weighed4 ,a gauge is ordinarily provided with this type of calorimeter1 which shows the pressure in its inner chamber and the flow of steam for a given period1 this latter scale being graduated by trial4 ,the instrument1 like a throttling calorimeter1 should be well insulated to prevent losses from radiation4 ,while theoretically the separating calorimeter is not limited in capacity1 it is well in cases where the percentage of moisture present in the steam is known to be high1 to attach a throttling calorimeter to its exhaust4 ,this1 in effect1 is the using of the separating calorimeter as a small separator between the sampling nozzle and the throttling instrument1 and is necessary to insure the determination of the full percentage of moisture in the steam4 ,the sum of the percentages shown by the two instruments is the moisture content of the steam4 ,the steam passing through a separating calorimeter may be calculated by ,napier's formula1 the size of the orifice being known4 ,there are objections to such a calculation1 however1 in that it is difficult to accurately determine the areas of such small orifices4 ,further1 small orifices have a tendency to become partly closed by sediment that may be carried by the steam4 ,the more accurate method of determining the amount of steam passing through the instrument is as follows3 ,illustration3 ,fig4 #ag4 ,separating ,calorimeter ,a hose should be attached to the separator outlet leading to a vessel of water on a platform scale graduated to #a_/ajj of a pound4 ,the steam outlet should be connected to another vessel of water resting on a second scale4 ,in each case1 the weight of each vessel and its contents should be noted4 ,when ready for an observation1 the instrument should be blown out thoroughly so that there will be no water within the separator4 ,the separator drip should then be closed and the steam hose inserted into the vessel of water at the same instant4 ,when the separator has accumulated a sufficient quantity of water1 the valve of the instrument should be closed and the hose removed from the vessel of water4 ,the separator should be emptied into the vessel on its scale4 ,the final weight of each vessel and its contents are to be noted and the differences between the final and original weights will represent the weight of moisture collected by the separator and the weight of steam from which the moisture has been taken4 ,the proportion of moisture can then be calculated from the following formula3 #ajj w x ----- 7#g7 ,w - w ,where x per cent moisture in steam1 ,w weight of steam condensed1 w weight of moisture as taken out by the separating calorimeter4 ,sampling ,nipple--,the principle source of error in steam calorimeter determinations is the failure to obtain an average sample of the steam delivered by the boiler and it is extremely doubtful whether such a sample is ever obtained4 ,the two governing features in the obtaining of such a sample are the type of sampling nozzle used and its location4 ,the ,american ,society of ,mechanical ,engineers recommends a sampling nozzle made of one-half inch iron pipe closed at the inner end and the interior portion perforated with not less than twenty one-eighth inch holes equally distributed from end to end and preferably drilled in irregular or spiral rows1 with the first hole not less than one-half inch from the wall of the pipe4 ,many engineers object to the use of a perforated sampling nipple because it ordinarily indicates a higher percentage of moisture than is actually present in the steam4 ,this is due to the fact that if the perforations come close to the inner surface of the pipe1 the moisture1 which in many instances clings to this surface1 will flow into the calorimeter and cause a large error4 ,where a perforated nipple is used1 in general it may be said that the perforations should be at least one inch from the inner pipe surface4 ,a sampling nipple1 open at the inner end and unperforated1 undoubtedly gives as accurate a measure as can be obtained of the moisture in the steam passing that end4 ,it would appear that a satisfactory method of obtaining an average sample of the steam would result from the use of an open end unperforated nipple passing through a stuffing box which would allow the end to be placed at any point across the diameter of the steam pipe4 ,incidental to a test of a #ae1jjj ,k4 ,w4 steam engine turbine unit1 ,mr4 ,h4 ,g4 ,stott and ,mr4 ,r4 ,g4 ,s4 ,pigott1 finding no experimental data bearing on the subject of low pressure steam quality determinations1 made a investigation of the subject and the sampling nozzle illustrated in ,fig4 #ah was developed4 ,in speaking of sampling nozzles in the determination of the moisture content of low pressure steam1 ,mr4 ,pigott says1 the ordinary standard perforated pipe sampler is absolutely worthless in giving a true sample and it is vital that the sample be abstracted from the main without changing its direction or velocity until it is safely within the sample pipe and entirely isolated from the rest of the steam4 ,illustration3 ,fig4 #ah4 ,stott and ,pigott ,sampling ,nozzle ,it would appear that the nozzle illustrated is undoubtedly the best that has been developed for use in the determination of the moisture content of steam1 not only in the case of low1 but also in high pressure steam4 ,location of ,sampling ,nozzle--,the calorimeter should be located as near as possible to the point from which the steam is taken and the sampling nipple should be placed in a section of the main pipe near the boiler and where there is no chance of moisture pocketing in the pipe4 ,the ,american ,society of ,mechanical ,engineers recommends that a sampling nipple1 of which a description has been given1 should be located in a vertical main1 rising from the boiler with its closed end extending nearly across the pipe4 ,where non-return valves are used1 or where there are horizontal connections leading from the boiler to a vertical outlet1 water may collect at the lower end of the uptake pipe and be blown upward in a spray which will not be carried away by the steam owing to a lack of velocity4 ,a sample taken from the lower part of this pipe will show a greater amount of moisture than a true sample4 ,with goose-neck connections a small amount of water may collect on the bottom of the pipe near the upper end where the inclination is such that the tendency to flow backward is ordinarily counterbalanced by the flow of steam forward over its surface2 but when the velocity momentarily decreases the water flows back to the lower end of the goose-neck and increases the moisture at that point1 making it an undesirable location for sampling4 ,in any case1 it should be borne in mind that with low velocities the tendency is for drops of entrained water to settle to the bottom of the pipe1 and to be temporarily broken up into spray whenever an abrupt bend or other disturbance is met4 ,illustration3 ,fig4 #ai4 ,illustrating the ,manner in which ,erroneous ,calorimeter ,readings may be ,obtained due to ,improper ,location of ,sampling ,nozzle ,case #a--;,horizontal pipe4 ,water flows at bottom4 ,if perforations in nozzle are too near bottom of pipe1 water piles against nozzle1 flows into calorimeter and gives false reading4 ,case #b--;,if nozzle located too near junction of two horizontal runs1 as at a1 condensation from vertical pipe which collects at this point will be thrown against the nozzle by the velocity of the steam1 resulting in a false reading4 ,nozzle should be located far enough above junction to be removed from water kept in motion by the steam velocity1 as at b4 ,case #c--;,condensation in bend will be held by velocity of the steam as shown4 ,when velocity is diminished during firing intervals and the like moisture flows back against nozzle1 a1 and false reading is obtained4 ,a true reading will be obtained at b provided condensation is not blown over on nozzle4 ,case #d--,where non-return valve is placed before a bend1 condensation will collect on steam line side and water will be swept by steam velocity against nozzle and false readings result4 ,fig4 #ai indicates certain locations of sampling nozzles from which erroneous results will be obtained1 the reasons being obvious from a study of the cuts4 ,before taking any calorimeter reading1 steam should be allowed to flow through the instrument freely until it is thoroughly heated4 ,the method of using a throttling calorimeter is evident from the description of the instrument given and the principle upon which it works4 ,illustration3 ,babcock ,wilcox ,superheater ,,superheated ,,steam ,superheated steam1 as already stated1 is steam the temperature of which exceeds that of saturated steam at the same pressure4 ,it is produced by the addition of heat to saturated steam which has been removed from contact with the water from which it was generated4 ,the properties of superheated steam approximate those of a perfect gas rather than of a vapor4 ,saturated steam cannot be superheated when it is in contact with water which is also heated1 neither can superheated steam condense without first being reduced to the temperature of saturated steam4 ,just so long as its temperature is above that of saturated steam at a corresponding pressure it is superheated1 and before condensation can take place that superheat must first be lost through radiation or some other means4 ,table #bdbj gives such properties of superheated steam for varying pressures as are necessary for use in ordinary engineering practice4 ,specific ,heat of ,superheated ,steam--,the specific heat of superheated steam at atmospheric pressure and near saturation point was determined by ,regnault1 in #ahfb1 who gives it the value of #j4dh4 ,regnault's value was based on four series of experiments1 all at atmospheric pressure and with about the same temperature range1 the maximum of which was #bca4a degrees centigrade4 ,for fifty years after ,regnault's determination1 this value was accepted and applied to higher pressures and temperatures as well as to the range of his experiments4 ,more recent investigations have shown that the specific heat is not a constant and varies with both pressure and the temperature4 ,a number of experiments have been made by various investigators and1 up to the present1 the most reliable appear to be those of ,knoblauch and ,jacob4 ,messrs4 ,marks and ,davis have used the values as determined by ,knoblauch and ,jacob with slight modifications4 ,the first consists in a varying of the curves at low pressures close to saturation because of thermodynamic evidence and in view of ,regnault's determination at atmospheric pressure4 ,the second modification is at high degrees of superheat to follow ,holborn's and ,henning's curve1 which is accepted as authentic4 ,for the sake of convenience1 the mean specific heat of superheated steam at various pressures and temperatures is given in tabulated form in ,table #be4 ,these values have been calculated from ,marks and ,davis ,steam ,tables by deducting from the total heat of one pound of steam at any pressure for any degree of superheat the total heat of one pound of saturated steam at the same pressure and dividing the difference by the number of degrees of superheat and1 therefore1 represent the average specific heat starting from that at saturation to the value at the particular pressure and temperature4#ba ,expressed as a formula this calculation is represented by ,hsup - ,hsat ,sp4 ,ht4 ----------------- 7#h7 ,ssup - ,ssat ,where ,hsup total heat of one pound of superheated steam at any pressure and temperature1 ,hsat total heat of one pound of saturated steam at same pressure1 ,ssup temperature of superheated steam taken1 ,ssat temperature of saturated steam corresponding to the pressure taken4 ,,table #be ,,mean ,,specific ,,heat ,,of ,,superheated ,,steam ,,calculated ,,from ,,marks ,,and ,,davis ,,tables ,gauge ,pressure ,degree of ,superheat #ej #fj #gj #hj #ij #ajj #aaj #abj #acj #ej 4#eah 4#eag 4#ead 4#eac 4#eaa 4#eaj 4#ejh 4#ejg 4#eje #fj 4#ebh 4#ebe 4#ebc 4#eba 4#eai 4#eag 4#eae 4#eac 4#eab #gj 4#ecf 4#ecd 4#eca 4#ebi 4#ebg 4#ebd 4#ebb 4#ebj 4#eah #hj 4#edd 4#edb 4#eci 4#ece 4#ecb 4#ecj 4#ebh 4#ebf 4#ebd #ij 4#eec 4#eej 4#edf 4#edc 4#eci 4#ecf 4#ecd 4#ecb 4#ebi #ajj 4#efb 4#eeg 4#eec 4#edi 4#edd 4#edb 4#eci 4#ecf 4#ecc #aaj 4#egj 4#efe 4#efj 4#eef 4#eeb 4#edh 4#ede 4#edb 4#eci #abj 4#egh 4#egc 4#efg 4#efa 4#eeg 4#eed 4#eej 4#edf 4#edc #acj 4#ehf 4#ehj 4#egd 4#efi 4#efd 4#efj 4#eee 4#eeb 4#edh #adj 4#eid 4#ehh 4#eha 4#ege 4#egj 4#efe 4#efa 4#eeg 4#eec #aej 4#fjd 4#eie 4#ehg 4#eha 4#egf 4#egj 4#eff 4#efa 4#eeg #afj 4#fab 4#fjc 4#eif 4#ehi 4#ehb 4#egf 4#ega 4#eff 4#efb #agj 4#fbj 4#fab 4#fjc 4#eie 4#ehh 4#ehb 4#egf 4#ega 4#eff #ahj 4#fbh 4#fah 4#faj 4#fja 4#eic 4#ehg 4#eha 4#ege 4#egj #aij 4#fch 4#fbg 4#fag 4#fjh 4#eii 4#eib 4#ehe 4#egi 4#egd #bjj 4#fdh 4#fce 4#fbd 4#fad 4#fje 4#eig 4#eij 4#ehd 4#egh #baj 4#fef 4#fdc 4#fca 4#fbj 4#faa 4#fjb 4#eie 4#ehh 4#ehc #bbj 4#ffd 4#fej 4#fcg 4#fbf 4#faf 4#fjg 4#fjj 4#eib 4#ehf #bcj 4#fgb 4#feh 4#fdd 4#fcc 4#fbb 4#fac 4#fje 4#eig 4#eia #bdj 4#fhd 4#ffh 4#fec 4#fdj 4#fbi 4#fai 4#faj 4#fjb 4#eie #bej 4#fib 4#fge 4#fei 4#fde 4#fcc 4#fbc 4#fad 4#fjf 4#eii ,gauge ,pressure ,degree of ,superheat ---------------------------------------- ------------- #adj #aej #afj #agj #ahj #aij #bjj #bbe #bej ---------------------------------------- -------------- #ej 4#ejd 4#ejc 4#ejb 4#eja 4#ejj 4#ejj 4#dii 4#dig 4#dif #fj 4#eaa 4#eji 4#ejh 4#ejg 4#ejf 4#ejd 4#ejd 4#ejb 4#ejj #gj 4#eaf 4#eae 4#eac 4#eab 4#eaa 4#eaj 4#eji 4#ejf 4#ejd #hj 4#ebb 4#ebj 4#eah 4#eaf 4#eae 4#ead 4#eac 4#eaa 4#ejh #ij 4#ebg 4#ebe 4#ebc 4#eba 4#eai 4#eah 4#eag 4#ead 4#eaj #ajj 4#eca 4#ebi 4#ebg 4#ebe 4#ebc 4#ebb 4#eba 4#eag 4#eac #aaj 4#ecf 4#ecd 4#ecb 4#ebi 4#ebh 4#ebf 4#ebe 4#ebj 4#eag #abj 4#edj 4#ecg 4#ece 4#ecc 4#eca 4#ebi 4#ebh 4#ebc 4#eai #acj 4#ede 4#edb 4#eci 4#ecg 4#ece 4#ecc 4#eca 4#ebg 4#ebc #adj 4#eej 4#edg 4#edd 4#eda 4#eci 4#ecf 4#ecd 4#ecj 4#ebf #aej 4#eed 4#eej 4#edg 4#edd 4#edb 4#eci 4#ecg 4#ecc 4#ebi #afj 4#eeh 4#eed 4#eea 4#edh 4#ede 4#edc 4#eda 4#ecf 4#eca #agj 4#efb 4#eeh 4#eee 4#eeb 4#edi 4#edf 4#edd 4#ech 4#ecc #ahj 4#eff 4#efa 4#eeh 4#eee 4#eeb 4#edi 4#edf 4#edj 4#ecf #aij 4#efi 4#efe 4#efb 4#eeh 4#eee 4#eeb 4#edi 4#edc 4#ech #bjj 4#egd 4#efi 4#eff 4#efb 4#eeh 4#eee 4#eeb 4#edf 4#eda #baj 4#egh 4#egc 4#efi 4#efe 4#efa 4#eeh 4#eee 4#edi 4#edc #bbj 4#eha 4#egg 4#egb 4#efh 4#efd 4#efa 4#eeh 4#eea 4#ede #bcj 4#ehe 4#ehj 4#ege 4#egb 4#efg 4#efd 4#efa 4#eed 4#edh #bdj 4#ehi 4#ehd 4#egi 4#ege 4#ega 4#efg 4#efd 4#eef 4#eej #bej 4#eic 4#ehg 4#ehb 4#egg 4#egd 4#egj 4#efg 4#eei 4#eec ,factor of ,evaporation with ,superheated ,steam--,when superheat is present in the steam during a boiler trial1 where superheated steam tables are available1 the formula for determining the factor of evaporation is that already given1 7#b71bb namely1 ,h - h ,factor of evaporation ----- ,l ,here ,h total heat in one pound of superheated steam from the table1 h and ,l having the same values as in 7#b74 ,where no such tables are available but the specific heat of superheat is known1 the formula becomes3 ,h - h ,sp4 ,ht47,t - t7 ,factor of evaporation ---------------------- ,l ,where ,h total heat in one pound of saturated steam at pressure existing in trial1 h sensible heat above #cb degrees in one pound of water at the temperature entering the boiler1 ,t temperature of superheated steam as determined in the trial1 t temperature of saturated steam corresponding to the boiler pressure1 ,sp4 ,ht4 mean specific heat of superheated steam at the pressure and temperature as found in the trial1 ,l latent heat of one pound of saturated steam at atmospheric pressure4 ,advantages of the ,use of ,superheated ,steam--,in considering the saving possible by the use of superheated steam1 it is too often assumed that there is only a saving in the prime movers1 a saving which is at least partially offset by an increase in the fuel consumption of the boilers generating steam4 ,this misconception is due to the fact that the fuel consumption of the boiler is only considered in connection with a definite weight of steam4 ,it is true that where such a definite weight is to be superheated1 an added amount of fuel must be burned4 ,with a properly designed superheater where the combined efficiency of the boiler and superheater will be at least as high as of a boiler alone1 the approximate increase in coal consumption for producing a given weight of steam will be as follows3 ,superheat ,added ,fuel ,degrees ,per ,cent #be #a4ei #ej #c4jg #ge #d4ch #ajj #e4fi #aej #h4ai #bjj #aj4eh ,these figures represent the added fuel necessary for superheating a definite weight of steam to the number of degrees as given4 ,the standard basis1 however1 of boiler evaporation is one of heat units and1 considered from such a standpoint1 again providing the efficiency of the boiler and superheater is as high1 as of a boiler alone1 there is no additional fuel required to generate steam containing a definite number of heat units whether such units be due to superheat or saturation4 ,that is1 if #f per cent more fuel is required to generate and superheat to #ajj degrees1 a definite weight of steam1 over what would be required to produce the same weight of saturated steam1 that steam when superheated1 will contain #f per cent more heat units above the fuel water temperature than if saturated4 ,this holds true if the efficiency of the boiler and superheater combined is the same as of the boiler alone4 ,as a matter of fact1 the efficiency of a boiler and superheater1 where the latter is properly designed and located1 will be slightly higher for the same set of furnace conditions than would the efficiency of a boiler in which no superheater were installed4 ,a superheater1 properly placed within the boiler setting in such way that products of combustion for generating saturated steam are utilized as well for superheating that steam1 will not in any way alter furnace conditions4 ,with a given set of such furnace conditions for a given amount of coal burned1 the fact that additional surface1 whether as boiler heating or superheating surface1 is placed in such a manner that the gases must sweep over it1 will tend to lower the temperature of the exit gases4 ,it is such a lowering of exit gas temperatures that is the ultimate indication of added efficiency4 ,though the amount of this added efficiency is difficult to determine by test1 that there is an increase is unquestionable4 ,where a properly designed superheater is installed in a boiler the heating surface of the boiler proper1 in the generation of a definite number of heat units1 is relieved of a portion of the work which would be required were these heat units delivered in saturated steam4 ,such a superheater needs practically no attention1 is not subject to a large upkeep cost or depreciation1 and performs its function without in any way interfering with the operation of the boiler4 ,its use1 therefore from the standpoint of the boiler room1 results in a saving in wear and tear due to the lower ratings at which the boiler may be run1 or its use will lead to the possibility of obtaining the same number of boiler horse power from a smaller number of boilers1 with the boiler heating surface doing exactly the same amount of work as if the superheaters were not installed4 ,the saving due to the added boiler efficiency that will be obtained is obvious4 ,following the course of the steam in a plant1 the next advantage of the use of superheated steam is the absence of water in the steam pipes4 ,the thermal conductivity of superheated steam1 that is1 its power to give up its heat to surrounding bodies1 is much lower than that of saturated steam and its heat1 therefore1 will not be transmitted so rapidly to the walls of the pipes as when saturated steam is flowing through the pipes4 ,the loss of heat radiated from a steam pipe1 assuming no loss in pressure1 represents the equivalent condensation when the pipe is carrying saturated steam4 ,in well-covered steam mains1 the heat lost by radiation when carrying superheated steam is accompanied only by a reduction of the superheat which1 if it be sufficiently high at the boiler1 will enable a considerable amount of heat to be radiated and still deliver dry or superheated steam to the prime movers4 ,it is in the prime movers that the advantages of the use of superheated steam are most clearly seen4 ,in an engine1 steam is admitted into a space that has been cooled by the steam exhausted during the previous stroke4 ,the heat necessary to warm the cylinder walls from the temperature of the exhaust to that of the entering steam can be supplied only by the entering steam4 ,if this steam be saturated1 such an adding of heat to the walls at the expense of the heat of the entering steam results in the condensation of a portion4 ,this initial condensation is seldom less than from #bj to #cj per cent of the total weight of steam entering the cylinder4 ,it is obvious that if the steam entering be superheated1 it must be reduced to the temperature of saturated steam at the corresponding pressure before any condensation can take place4 ,if the steam be superheated sufficiently to allow a reduction in temperature equivalent to the quantity of heat that must be imparted to the cylinder walls and still remain superheated1 it is clear that initial condensation is avoided4 ,for example3 assume one pound of saturated steam at #bjj pounds gauge pressure to enter a cylinder which has been cooled by the exhaust4 ,assume the initial condensation to be #bj per cent4 ,the latent heat of the steam is given up in condensation2 hence1 4#bj #hch #afg4f ,b4 t4 u4 are given up by the steam4 ,if one pound of superheated steam enters the same cylinder1 it would have to be superheated to a point where its total heat is #aaii #afh #acfg ,b4 t4 u4 or1 at #bjj pounds gauge pressure1 superheated approximately #cbe degrees if the heat given up to the cylinder walls were the same as for the saturated steam4 ,as superheated steam conducts heat less rapidly than saturated steam1 the amount of heat imparted will be less than for the saturated steam and consequently the amount of superheat required to prevent condensation will be less than the above figure4 ,this1 of course1 is the extreme case of a simple engine with the range of temperature change a maximum4 ,as cylinders are added1 the range in each is decreased and the condensation is proportionate4 ,the true economy of the use of superheated steam is best shown in a comparison of the heat consumption of an engine4 ,this is the number of heat units required in developing one indicated horse power and the measure of the relative performance of two engines is based on a comparison of their heat consumption as the measure of a boiler is based on its evaporation from and at #bab degrees4 ,the water consumption of an engine in pounds per indicated horse power is in no sense a true indication of its efficiency4 ,the initial pressures and corresponding temperatures may differ widely and thus make a difference in the temperature of the exhaust and hence in the temperature of the condensed steam returned to the boiler4 ,for example3 suppose a certain weight of steam at #aej pounds absolute pressure and #ceh degrees be expanded to atmospheric pressure1 the temperature then being #bab degrees4 ,if the same weight of steam be expanded from an initial pressure of #abe pounds absolute and #cdd degrees1 to enable it to do the same amount of work1 that is1 to give up the same amount of heat1 expansion then must be carried to a point below atmospheric pressure to1 say1 #ac pounds absolute1 the final temperature of the steam then being #bjf degrees4 ,in actual practice1 it has been observed that the water consumption of a compound piston engine running on #bf-;inch vacuum and returning the condensed steam at #adj degrees was approximately the same as when running on #bh-;inch vacuum and returning water at #ij degrees4 ,with an equal water consumption for the two sets of conditions1 the economy in the former case would be greater than in the latter1 since it would be necessary to add less heat to the water returned to the boiler to raise it to the steam temperature4 ,the lower the heat consumption of an engine per indicated horse power1 the higher its economy and the less the number of heat units must be imparted to the steam generated4 ,this in turn leads to the lowering of the amount of fuel that must be burned per indicated horse power4 ,with the saving in fuel by the reduction of heat consumption of an engine indicated1 it remains to be shown the effect of the use of superheated steam on such heat consumption4 ,as already explained1 the use of superheated steam reduces condensation not only in the mains but especially in the steam cylinder1 leaving a greater quantity of steam available to do the work4 ,furthermore1 a portion of the saturated steam introduced into a cylinder will condense during adiabatic expansion1 this condensation increasing as expansion progresses4 ,since superheated steam cannot condense until it becomes saturated1 not only is initial condensation prevented by its use but also such condensation as would occur during expansion4 ,when superheated sufficiently1 steam delivered by the exhaust will still be dry4 ,in the avoidance of such condensation1 there is a direct saving in the heat consumption of an engine1 the heat given up being utilized in the developing of power and not in changing the condition of the working fluid4 ,that is1 while the number of heat units lost in overcoming condensation effects would be the same in either case1 when saturated steam is condensed the water of condensation has no power to do work while the superheated steam1 even after it has lost a like number of heat units1 still has the power of expansion4 ,the saving through the use of superheated steam in the heat consumption of an engine decreases demands on the boiler and hence the fuel consumption per unit of power4 ,superheated ,steam for ,steam ,turbines--,experience in using superheated steam in connection with steam turbines has shown that it leads to economy and that it undoubtedly pays to use superheated steam in place of saturated steam4 ,this is so well established that it is standard practice to use superheated steam in connection with steam turbines4 ,aside from the economy secured through using superheated steam1 there is an important advantage arising through the fact that it materially reduces the erosion of the turbine blades by the action of water that would be carried by saturated steam4 ,in using saturated steam in a steam turbine or piston engine1 the work done on expanding the steam causes condensation of a portion of the steam1 so that even were the steam dry on entering the turbine1 it would contain water on leaving the turbine4 ,by superheating the steam the water that exists in the low pressure stages of the turbine may be reduced to an amount that will not cause trouble4 ,again1 if saturated steam contains moisture1 the effect of this moisture on the economy of a steam turbine is to reduce the economy to a greater extent than the proportion by weight of water1 one per cent of water causing approximately a falling off of #b per cent in the economy4 ,the water rate of a large economical steam turbine with superheated steam is reduced about one per cent1 for every #ab degrees of superheat up to #bjj degrees ,fahrenheit of superheat4 ,to superheat one pound of steam #ab degrees requires about #g ,b4 t4 u4 and if #ajej ,b4 t4 u4 are required at the boiler to evaporate one pound of the saturated steam from the temperature of the feed water1 the heat required for the superheated steam would be #ajeg degrees4 ,one per cent of saving1 therefore1 in the water consumption would correspond to a net saving of about one-third of one per cent in the coal consumption4 ,on this basis #ajj degrees of superheat with an economical steam turbine would result in somewhat over #c per cent of saving in the coal for equal boiler efficiencies4 ,as a boiler with a properly designed superheater placed within the setting is more economical for a given capacity than a boiler without a superheater1 the minimum gain in the coal consumption would be1 say1 #d or #e per cent as compared to a plant with the same boilers without superheaters4 ,the above estimates are on the basis of a thoroughly dry saturated steam or steam just at the point of being superheated or containing a few degrees of superheat4 ,if the saturated steam is moist1 the saving due to superheat is more and ordinarily the gain in economy due to superheated steam1 for equal boiler efficiencies1 as compared with commercially dry steam is1 say1 #e per cent for each #ajj degrees of superheat4 ,aside from this gain1 as already stated1 superheated steam prevents erosion of the turbine buckets that would be caused by water in the steam1 and for the reasons enumerated it is standard practice to use superheated steam for turbine work4 ,the less economical the steam motor1 the more the gain due to superheated steam1 and where there are a number of auxiliaries that are run with superheated steam1 the percentage of gain will be greater than the figures given above1 which are the minimum and are for the most economical type of large steam turbines4 ,an example from actual practice will perhaps best illustrate and emphasize the foregoing facts4 ,in ,october #aiji1 a series of comparable tests were conducted by ,the ,babcock ,wilcox ,co4 on the steam yacht ,idalia to determine the steam consumption both with saturated and superheated steam of the main engine on that yacht1 including as well the feed pump1 circulating pump and air pump4 ,these tests are more representative than are most tests of like character in that the saving in the steam consumption of the auxiliaries1 which were much more wasteful than the main engine1 formed an important factor4 ,a rsum of these tests was published in the ,journal of the ,society of ,naval ,engineers1 ,november #aiji4 ,the main engines of the ,idalia are four cylinder1 triple expansion1 #aa-a_/b #ai inches by #bb-aa_/af #ah inches stroke4 ,steam is supplied by a ,babcock ,wilcox marine boiler having #bejj square feet of boiler heating surface1 #cdj square feet of superheating surface and #fe square feet of grate surface4 ,the auxiliaries consist of a feed pump #f #d #f inches1 an independent air pump #f #ab #h inches1 and a centrifugal pump driven by a reciprocating engine #e-g_/af #e inches4 ,under ordinary operating conditions the superheat existing is about #ajj degrees ,fahrenheit4 ,tests were made with various degrees of superheat1 the amount being varied by by-passing the gases and in the tests with the lower amounts of superheat by passing a portion of the steam from the boiler to the steam main without passing it through the superheater4 ,steam temperature readings were taken at the engine throttle4 ,in the tests with saturated steam1 the superheater was completely cut out of the system4 ,careful calorimeter measurements were taken1 showing that the saturated steam delivered to the superheater was dry4 ,the weight of steam used was determined from the weight of the condensed steam discharge from the surface condenser1 the water being pumped from the hot well into a tank mounted on platform scales4 ,the same indicators1 thermometers and gauges were used in all the tests1 so that the results are directly comparable4 ,the indicators used were of the outside spring type so that there was no effect of the temperature of the steam4 ,all tests were of sufficient duration to show a uniformity of results by hours4 ,a summary of the results secured is given in ,table #bf1 which shows the water rate per indicated horse power and the heat consumption4 ,the latter figures are computed on the basis of the heat imparted to the steam above the actual temperature of the feed water and1 as stated1 these are the results that are directly comparable4 ,,table #bf ,,results ,,of ,,idalia ,,tests ,date #aiji ,oct4 #aa,oct4 #ad,oct4 #ad,oct4 #ab,oct4 #ac ,degrees of superheat ,fahrenheit #j #eg #hh #if #aje ,pressures1 pounds per ,throttle #aij #aif #bja #aih #bjc square inch above ,first ,atmospheric ,pressure ,receiver #fh4d #ff4j #fd4c #fa4i #fc4j ,second ,receiver #i4g #i4b #h4g #g4h #h4d ,vacuum1 inches #be4e #be4i #be4i #be4d #be4b ,temperature1 ,degrees ,fahrenheit ,feed #bja #bjf #bje #bjb #bjj ,hot ,well #aaf #aji4e #aae #aaa4e #aaa ,revolutions per minute ,air ,pump #eg #ef #ec #ed #de ,circulating ,pump #aif #aih #aif #aih #aig ,main ,engine #aid4c #aia4e #aie4a #aia4e #aic4a ,indicated ,horse ,power1 ,main ,engine #eab4c #die4b #eba4a #dih4c #ejb4b ,water per hour1 total pounds #icig #hdcj #hbcd #gijb #ggij ,water per indicated ,horse ,power1 pounds #ah4c #ag4j #ae4h #ae4h #ae4e ,b4 t4 u4 per minute per indicated ,horse ,power #cad #cjj #bhd #bhf #bhc ,per cent ,saving of ,steam 444 #g4a #ac4g #ac4g #ae4c ,percent ,saving of ,fuel 7computed7 444 #d4d #i4e #h4i #i4i ,the table shows that the saving in steam consumption with #aje degrees of superheat was #ae4c per cent and in heat consumption about #aj per cent4 ,this may be safely stated to be a conservative representation of the saving that may be accomplished by the use of superheated steam in a plant as a whole1 where superheated steam is furnished not only to the main engine but also to the auxiliaries4 ,the figures may be taken as conservative for the reason that in addition to the saving as shown in the table1 there would be in an ordinary plant a saving much greater than is generally realized in the drips1 where the loss with saturated steam is greatly in excess of that with superheated steam4 ,the most conclusive and most practical evidence that a saving is possible through the use of superheated steam is in the fact that in the largest and most economical plants it is used almost without exception4 ,regardless of any such evidence1 however1 there is a deep rooted conviction in the minds of certain engineers that the use of superheated steam will involve operating difficulties which1 with additional first cost1 will more than offset any fuel saving4 ,there are1 of course1 conditions under which the installation of superheaters would in no way be advisable4 ,with a poorly designed superheater1 no gain would result4 ,in general1 it may be stated that in a new plant1 properly designed1 with a boiler and superheater which will have an efficiency at least as high as a boiler without a superheater1 a gain is certain4 ,such a gain is dependent upon the class of engine and the power plant equipment in general4 ,in determining the advisability of making a superheater installation1 all of the factors entering into each individual case should be considered and balanced1 with a view to determining the saving in relation to cost1 maintenance1 depreciation etc4 ,in highly economical plants1 where the water consumption for an indicated horse power is low1 the gain will be less than would result from the use of superheated steam in less economical plants where the water consumption is higher4 ,it is impossible to make an accurate statement as to the saving possible but1 broadly1 it may vary from #c to #e per cent for #ajj degrees of superheat in the large and economical plants using turbines or steam engines1 in which there is a large ratio of expansion1 to from #aj to #be per cent for #ajj degrees of superheat for the less economical steam motors4 ,though a properly designed superheater will tend to raise rather than to decrease the boiler efficiency1 it does not follow that all superheaters are efficient1 for if the gases in passing over the superheater do not follow the path they would ordinarily take in passing over the boiler heating surface1 a loss may result4 ,this is noticeably true where part of the gases are passed over the superheater and are allowed to pass over only a part or in some cases none of the boiler heating surface4 ,with moderate degrees of superheat1 from #ajj to #bjj degrees1 where the piping is properly installed1 there will be no greater operating difficulties than with saturated steam4 ,engine and turbine builders guarantee satisfactory operation with superheated steam4 ,with high degrees of superheat1 say1 over #bej degrees1 apparatus of a special nature must be used and it is questionable whether the additional care and liability to operating difficulties will offset any fuel saving accomplished4 ,it is well established1 however1 that the operating difficulties1 with the degrees of superheat to which this article is limited1 have been entirely overcome4 ,the use of cast-iron fittings with superheated steam has been widely discussed4 ,it is an undoubted fact that while in some instances superheated steam has caused deterioration of such fittings1 in others cast-iron fittings have been used with #aej degrees of superheat without the least difficulty4 ,the quality of the cast iron used in such fittings has doubtless a large bearing on the life of such fittings for this service4 ,the difficulties that have been encountered are an increase in the size of the fittings and eventually a deterioration great enough to lead to serious breakage1 the development of cracks1 and when flanges are drawn up too tightly1 the breaking of a flange from the body of the fitting4 ,the latter difficulty is undoubtedly due1 in certain instances1 to the form of flange in which the strain of the connecting bolts tended to distort the metal4 ,the ,babcock ,wilcox ,co4 have used steel castings in superheated steam work over a long period and experience has shown that this metal is suitable for the service4 ,there seems to be a general tendency toward the use of steel fittings4 ,in ,european practice1 until recently1 cast iron was used with apparently satisfactory results4 ,the claim of ,european engineers was to the effect that their cast iron was of better quality than that found in this country and thus explained the results secured4 ,recently1 however1 certain difficulties have been encountered with such fittings and ,european engineers are leaning toward the use of steel for this work4 ,the degree of superheat produced by a superheater placed within the boiler setting will vary according to the class of fuel used1 the form of furnace1 the condition of the fire and the rate at which the boiler is being operated4 ,this is necessarily true of any superheater swept by the main body of the products of combustion and is a fact that should be appreciated by the prospective user of superheated steam4 ,with a properly designed superheater1 however1 such fluctuations would not be excessive1 provided the boilers are properly operated4 ,as a matter of fact the point to be guarded against in the use of superheated steam is that a maximum should not be exceeded4 ,while1 as stated1 there may be a considerable fluctuation in the temperature of the steam as delivered from individual superheaters1 where there are a number of boilers on a line the temperature of the combined flow of steam in the main will be found to be practically a constant1 resulting from the offsetting of various furnace conditions of one boiler by another4 ,illustration3 #hdjj ,horse-power ,installation of ,babcock ,wilcox ,boilers and ,superheaters at the ,butler ,street ,plant of the ,georgia ,railway and ,power ,co41 ,atlanta1 ,ga4 ,this ,company ,operates a ,total of #ae1bjj ,horse ,power of ,babcock ,wilcox ,boilers ,,properties ,,of ,,air ,pure air is a mechanical mixture of oxygen and nitrogen4 ,while different authorities give slightly varying values for the proportion of oxygen and nitrogen contained1 the generally accepted values are3 ,by volume1 oxygen #bj4ia per cent1 nitrogen #gi4ji per cent4 ,by weight1 oxygen #bc4ae per cent1 nitrogen #gf4he per cent4 ,air in nature always contains other constituents in varying amounts1 such as dust1 carbon dioxide1 ozone and water vapor4 ,being perfectly elastic1 the density or weight per unit of volume decreases in geometric progression with the altitude4 ,this fact has a direct bearing in the proportioning of furnaces1 flues and stacks at high altitudes1 as will be shown later in the discussion of these subjects4 ,the atmospheric pressures corresponding to various altitudes are given in ,table #ab4 ,the weight and volume of air depend upon the pressure and the temperature1 as expressed by the formula3 ,pv #ec4cc ,t 7#i7 ,where ,p the absolute pressure in pounds per square foot1 v the volume in cubic feet of one pound of air1 ,t the absolute temperature of the air in degrees ,fahrenheit1 #ec4cc a constant for air derived from the ratio of pressure1 volume and temperature of a perfect gas4 ,the weight of one cubic foot of air will obviously be the reciprocal of its volume1 that is1 #a_/v pounds4 ,,table #bg ,,volume ,,and ,,weight ,,of ,,air ,,at ,,atmospheric ,,pressure ,,at ,,various ,,temperatures ,volume ,temperature ,one ,pound ,weight ,one ,degrees in ,cubic ,foot ,fahrenheit ,cubic ,feet in ,pounds #cb #ab4cij 4#jhjgaj #ej #ab4hdc 4#jgghfc #ee #ab4ifi 4#jggajg #fj #ac4jie 4#jgfcfe #fe #ac4bba 4#jgefcg #gj #ac4cdg 4#jgdibc #ge #ac4dgc 4#jgdbbc #hj #ac4eii 4#jgcece #he #ac4gbe 4#jgbhfj #ij #ac4hea 4#jgbaig #ie #ac4igg 4#jgaedf #ajj #ad4ajc 4#jgjijg #aaj #ad4cee 4#jfiffb #abj #ad4fjg 4#jfhdfj #acj #ad4hei 4#jfgbii #adj #ae4aaa 4#jffagg #aej #ae4cfc 4#jfejib #afj #ae4fae 4#jfdjda #agj #ae4hfg 4#jfcjbd #ahj #af4aai 4#jfbjci #aij #af4cga 4#jfajhd #bjj #af4fbc 4#jfjaeh #baj #af4hge 4#jeibei #bab #af4ibe 4#jeijhd #bbj #ag4abg 4#jehchh #bcj #ag4cgi 4#jegeda #bdj #ag4fca 4#jefgah #bej #ag4hhc 4#jeeiai #bfj #ah4ace 4#jeeadb #bgj #ah4chg 4#jedchf #bhj #ah4fci 4#jecfea #bij #ah4hia 4#jebice #cjj #ai4adc 4#jebbch #cbj #ai4fdg 4#jejhih #cdj #bj4aea 4#jdifbe #cfj #bj4fee 4#jdhdad #chj #ba4aei 4#jdgbfa #djj #ba4ffc 4#jdfafb #dbe #bb4bic 4#jddheg #dej #bb4ibc 4#jdcfbd #dge #bc4eed 4#jdbdef #ejj #bd4ahd 4#jdacej #ebe #bd4had 4#jdjcjj #eej #be4ddd 4#jcicjb #ege #bf4jgd 4#jchceb #fjj #bf4gjd 4#jcgddh #fej #bg4ifd 4#jcegfj #gjj #bi4bbd 4#jcdbai #gej #cj4dhd 4#jcbhjd #hjj #ca4gdd 4#jcaejb #hej #cc4jjd 4#jcjbii ,example3 ,required the volume of air in cubic feet under #fj4c pounds gauge pressure per square inch at #aae degrees ,fahrenheit4 ,p #add 7#ad4g #fj4c7 #aj1hjj4 ,t #aae #dfj #ege degrees4 #ec4cc #ege ,hence v ----------- #b4hd cubic feet1 and #aj1hjj #a #a ,weight per cubic foot - ---- #j4ceb pounds4 v #b4hd ,table #bg gives the weights and volumes of air under atmospheric pressure at varying temperatures4 ,formula 7#i7 holds good for other gases with the change in the value of the constant as follows3 ,for oxygen #dh4bd1 nitrogen #ed4ig1 hydrogen #gfe4ga4 ,the specific heat of air at constant pressure varies with its temperature4 ,a number of determinations of this value have been made and certain of those ordinarily accepted as most authentic are given in ,table #bh4 ,,table #bh ,,specific ,,heat ,,of ,,air ,,at ,,constant ,,pressure ,,and ,,various ,,temperatures ,temperature ,range ,degrees ,degrees ,specific ,heat ,authority ,centigrade ,fahrenheit -#cj- #aj -#bb- #ej #j4bcgg ,regnault #j-ajj #cb- #bab #j4bcgd ,regnault #j-bjj #cb- #cib #j4bcge ,regnault #bj-ddj #fh- #hbd #j4bcff ,holborn and ,curtis #bj-fcj #fh-aaff #j4bdbi ,holborn and ,curtis #bj-hjj #fh-adgb #j4bdcj ,holborn and ,curtis #j-bjj #cb- #cib #j4bchi ,wiedemann ,this value is of particular importance in waste heat work and it is regrettable that there is such a variation in the different experiments4 ,mallard and ,le ,chatelier determined values considerably higher than any given in ,table #bh4 ,all things considered in view of the discrepancy of the values given1 there appears to be as much ground for the use of a constant value for the specific heat of air at any temperature as for a variable value4 ,where this value is used throughout this book1 it has been taken as #j4bd4 ,air may carry a considerable quantity of water vapor1 which is frequently #c per cent of the total weight4 ,this fact is of importance in problems relating to heating drying and the compressing of air4 ,table #bi gives the amount of vapor required to saturate air at different temperatures1 its weight1 expansive force1 etc41 and contains sufficient information for solving practically all problems of this sort that may arise4 ,,table #bi ,,weights ,,of ,,air1 ,,vapor ,,of ,,water1 ,,and ,,saturated ,,mixtures ,,of ,,air ,,and ,,vapor ,,at ,,different ,,temperatures1 ,,under ,,the ,,ordinary ,,atmospheric ,,pressure ,,of #bi4iba ,,inches ,,of ,,mercury ,column ,headings3 #a3 ,temperature ,degrees ,fahrenheit #b3 ,volume of ,dry ,air at ,different ,temperatures1 the ,volume at #cb ,degrees being #a4jjj #c3 ,weight of ,cubic ,foot of ,dry ,air at the ,different ,temperatures ,pounds #d3 ,elastic ,force of ,vapor in ,inches of ,mercury 7,regnault7 #e3 ,elastic ,force of the ,air in the ,mixture of ,air and ,vapor in ,inches of ,mercury #f3 ,weight of the ,air in ,pounds #g3 ,weight of the ,vapor in ,pounds #h3 ,total ,weight of ,mixture in ,pounds #i3 ,weight of ,vapor ,mixed with ,one ,pound of ,air1 in ,pounds #aj3 ,weight of ,dry ,air ,mixed with ,one ,pound of ,vapor1 in ,pounds #aa3 ,cubic ,feet of ,vapor from ,one ,pound of ,water at its own ,pressure in ,column #d ,mixtures of ,air ,saturated with ,vapor ,weight of ,cubic ,foot of the ,mixture of ,air and ,vapor #a #b #c #d #e #f #g #h #i #aj #aa #j 4#ice4jhfd 4#jddbi4hgg4jhfc4jjjjgi4jhfcgi 4#jjjibajib4d #ab 4#ifj4jhdb 4#jgdbi4hdi4jhdj4jjjacj4jhdacj 4#jjaee #fdf4a #bb 4#ihj4jhbd 4#aahbi4hjc4jhba4jjjbjb4jhbcjb 4#jjbde #djf4d #cba4jjj4jhjg 4#ahabi4gdj4jhjb4jjjcjd4jhjejd 4#jjcgi #bfc4ha #cbhi #dba4jbj4jgia 4#bfgbi4fed4jghd4jjjddj4jghhdj 4#jjefa #agh4ah #bbeb #eba4jda4jggf 4#chhbi4ecc4jgff4jjjfbg4jggbbg 4#jjhaj #abb4ag #aeie #fba4jfa4jgfa 4#eefbi4cfe4jgdg4jjjhha4jgeeha 4#jaagi #hd4gi #aace #gba4jhb4jgdg 4#ghebi4acf4jgbg4jjabba4jgciba 4#jafhj #ei4ed #hai #hba4ajb4jgcc #a4jibbh4hbi4jgjf4jjaffg4jgbbfg 4#jbcfa #db4ce #fjj #iba4abb4jgbj #a4ejabh4dbj4jfhd4jjbbej4jgjgag 4#jcbhi #cj4dj #ddd #ajba4adc4jgjg #b4jcfbg4hhe4jfei4jjbiig4jfhhig 4#jdedg #ba4ih #ccd #aaba4afc4jfid #b4gcabg4aij4jfca4jjcidf4jfgjdf 4#jfbec #ae4ii #bec #abba4ahd4jfhb #c4fbabf4cjj4jeii4jjeadb4jfejdb 4#jhehd #aa4fe #aid #acba4bjd4jfga #d4gebbe4afi4jefd4jjffci4jfcjci 4#aagga #h4di #aea #adba4bbd4jffj #f4afebc4gef4jebd4jjhdgc4jfjhgc 4#afagj #f4ah #aah #aeba4bde4jfdi #g4icjba4iia4jdgg4jajgaf4jehdaf 4#bbdfe #d4de #ic4c #afba4bfe4jfchaj4jiiai4hbb4jdbc4jacdae4j eegae 4#cagac #c4ae #gd4e #agba4bhe4jfbhab4gehag4afc4jcfj4jaffhb4j ebfhb 4#dfcch #b4af #ei4b #ahba4cjf4jfahae4ifjac4ifa4jbhh4jbjecf4j diccf 4#gacjj #a4djb #dh4f #aiba4cbf4jfjiai4hbhaj4jic4jbje4jbeadb4j defdb #a4bbfdc 4#hae #ci4h #bjba4cdg4jfjjbd4dej #e4dga4jaji4jcjede4jdadde #b4hjbcj 4#ceg #cb4g #baba4cfg4jeiabi4iba #j4jjj4jjjj4jcfhbj4jcfhbj;,infinite 4#jjj #bg4a ,column #e barometer pressure of #bi4iba1 minus the proportion of this due to vapor pressure from column #d4 ,,combustion ,combustion may be defined as the rapid chemical combination of oxygen with carbon1 hydrogen and sulphur1 accompanied by the diffusion of heat and light4 ,that portion of the substance thus combined with the oxygen is called combustible4 ,as used in steam engineering practice1 however1 the term combustible is applied to that portion of the fuel which is dry and free from ash1 thus including both oxygen and nitrogen which may be constituents of the fuel1 though not in the true sense of the term combustible4 ,combustion is perfect when the combustible unites with the greatest possible amount of oxygen1 as when one atom of carbon unites with two atoms of oxygen to form carbon dioxide1 ,,co#b4 ,the combustion is imperfect when complete oxidation of the combustible does not occur1 or where the combustible does not unite with the maximum amount of oxygen1 as when one atom of carbon unites with one atom of oxygen to form carbon monoxide1 ,,co1 which may be further burned to carbon dioxide4 ,kindling ,point--,before a combustible can unite with oxygen and combustion takes place1 its temperature must first be raised to the ignition or kindling point1 and a sufficient time must be allowed for the completion of the combustion before the temperature of the gases is lowered below that point4 ,table #cj1 by ,stromeyer1 gives the approximate kindling temperatures of different fuels4 ,,table #cj ,,kindling ,,temperature ,,of ,,various ,,fuels ,degrees ,fahrenheit ,lignite ,dust #cjj ,dried ,peat #dce ,sulphur #dgj ,anthracite ,dust #egj ,coal #fjj ,coke ,red ,heat ,anthracite ,red ,heat1 #gej ,carbon ,monoxide ,red ,heat1 #abaa ,hydrogen #ajcj or #abij ,combustibles--,the principal combustibles in coal and other fuels are carbon1 hydrogen and sulphur1 occurring in varying proportions and combinations4 ,carbon is by far the most abundant as is indicated in the chapters on fuels4 ,hydrogen in a free state occurs in small quantities in some fuels1 but is usually found in combination with carbon1 in the form of hydrocarbons4 ,the density of hydrogen is #j4jfif 7,air #a7 and its weight per cubic foot1 at #cb degrees ,fahrenheit and under atmospheric pressure1 is #j4jjefba pounds4 ,sulphur is found in most coals and some oils4 ,it is usually present in combined form1 either as sulphide of iron or sulphate of lime2 in the latter form it has no heat value4 ,its presence in fuel is objectionable because of its tendency to aid in the formation of clinkers1 and the gases from its combustion1 when in the presence of moisture1 may cause corrosion4 ,nitrogen is drawn into the furnace with the air4 ,its density is #j4ifgc 7,air #a72 its weight1 at #cb degrees ,fahrenheit and under atmospheric pressure1 is #j4jghbi pounds per cubic foot2 each pound of air at atmospheric pressure contains #j4gfhe pounds of nitrogen1 and one pound of nitrogen is contained in #a4cja pounds of air4 ,nitrogen performs no useful office in combustion and passes through the furnace without change4 ,it dilutes the air1 absorbs heat1 reduces the temperature of the products of combustion1 and is the chief source of heat losses in furnaces4 ,calorific ,value--,each combustible element of gas will combine with oxygen in certain definite proportions and will generate a definite amount of heat1 measured in ,b4 t4 u4 ,this definite amount of heat per pound liberated by perfect combustion is termed the calorific value of that substance4 ,table #ca1 gives certain data on the reactions and results of combustion for elementary combustibles and several compounds4 ,,table #ca ,,oxygen ,,and ,,air ,,required ,,for ,,combustion ,,at #cb ,,degrees ,,and #bi4ib ,,inches ,column headings3 #a3 ,oxidizable ,substance or ,combustible #b3 ,chemical ,symbol #c3 ,atomic or ,combining ,weight #d3 ,chemical ,reaction #e3 ,product of ,combustion #f3 ,oxygen per ,pound of ,column #a ,pounds #g3 ,nitrogen per ,pound of ,column #a4 #c4cbbc ,o ,pounds #h3 ,air per ,pound of ,column #a4 #d4cbbd ,o ,pounds #i3 ,gaseous ,product per ,pound of ,column #abe ,column #h ,pounds #aj3 ,heat ,value per ,pound of ,column #a ,b4 t4 u4 #aa3 ,volumes of ,column #a ,entering ,combination ,volume #ab3 ,volumes of ,oxygen ,combining with ,column #aa ,volume #ac3 ,volumes of ,product ,formed ,volume #ad3 ,volume per ,pound of ,column #a in ,gaseous ,form ,cubic ,feet #ae3 ,volume of ,oxygen per ,pound of ,column #a ,cubic ,feet #af3 ,volume of ,products of ,combustion per ,pound of ,column #a ,cubic ,feet #ag3 ,volume of ,nitrogen per ,pound of ,column #a #c4ghbbf ,column #ae ,cubic ,feet #ah3 ,volume of ,gas per pound of ,column #a ,column #aj ,column #ag ,cubic ,feet ,,by ,,weight #a #b #c #d #e #f ,carbon ,c #ab ,c#b,o ,,co#b ,carbon ,dioxide #b4ffg ,carbon ,c #ab ,c,o ,,co ,carbon ,monoxide #a4ccc ,carbon ,monoxide ,,co #bh ,,co,o ,,co#b ,carbon ,dioxide 4#ega ,hydrogen ,h #a #b;,h,o ,h#b,o ,water #h _/ ,,ch#dd,o ,carbon ,dioxide ,methane ,,ch#d #af #d ,,co#bb;,h#b,o and ,water _/ ,sulphur ,s #cb ,s#b,o ,,so#b ,sulphur ,dioxide #a #a #b #g #h #i #aj ,carbon ,c #h4he #aa4eb #ab4eb #adfjj ,carbon ,c #d4dc #e4gf #f4gf #ddej ,carbon ,monoxide ,,co #a4ij #b4dg #c4dg #ajaej ,hydrogen ,h #bf4ef #cd4ef #ce4ef #fbjjj ,methane ,,ch#d #ac4bh #ag4bh #ah4bh #bceej ,sulphur ,s #c4cb #d4cb #e4cb #djej ,,by ,,volume #a #b #aa #ab #ac #ad ,carbon ,c #a;,c #b #b;,,co#b #ad4ie ,carbon ,c #a;,c #a #b;,,co #ad4ie ,carbon ,monoxide ,,co #b;,,co #a #b;,,co#b #ab4hj ,hydrogen ,h #b;,h #a #b;,h#b,o #agi4cb ,methane ,,ch#d #a;,c#d;,h #d #a;,,co#b #b;,h#b,o #bb4da ,sulphur ,s #a,s #b #a,,so#b #e4fj #a #b #ae #af #ag #ah ,carbon ,c #bi4hi #bi4hi #aab4ih #adb4hg ,carbon ,c #ad4ie #bi4hi #ef4di #hf4ch ,carbon ,monoxide ,,co #f4dj #ab4hj #bd4bj #cg4jj ,hydrogen ,h #hi4ff #agi4cb #cci4ji #eah4da ,methane ,,ch#d #dd4hc #fg4cd #afi4ee #bcf4hi ,sulphur ,s #aa4ba #aa4ba #db4ci #ec4fj ,it will be seen from this table that a pound of carbon will unite with #b-b_/c pounds of oxygen to form carbon dioxide1 and will evolve #ad1fjj ,b4 t4 u4 ,as an intermediate step1 a pound of carbon may unite with #a-a_/c pounds of oxygen to form carbon monoxide and evolve #ddej ,b4 t4 u41 but in its further conversion to ,,co#b it would unite with an additional #a-a_/c times its weight of oxygen and evolve the remaining #aj1aej ,b4 t4 u4 ,when a pound of ,,co burns to ,,co#b1 however1 only #dcej ,b4 t4 u4 are evolved since the pound of ,,co contains but #c_/g pound carbon4 ,air ,required for ,combustion--,it has already been shown that each combustible element in fuel will unite with a definite amount of oxygen4 ,with the ultimate analysis of the fuel known1 in connection with ,table #ca1 the theoretical amount of air required for combustion may be readily calculated4 ,let the ultimate analysis be as follows3 ,per ,cent ,carbon #gd4gi ,hydrogen #d4ih ,oxygen #f4db ,nitrogen #a4bj ,sulphur #c4bd ,water #a4ee ,ash #g4hb ------ #ajj4jj ,when complete combustion takes place1 as already pointed out1 the carbon in the fuel unites with a definite amount of oxygen to form ,,co#b4 ,the hydrogen1 either in a free or combined state1 will unite with oxygen to form water vapor1 ,h#b,o4 ,not all of the hydrogen shown in a fuel analysis1 however1 is available for the production of heat1 as a portion of it is already united with the oxygen shown by the analysis in the form of water1 ,h#b,o4 ,since the atomic weights of ,h and ,o are respectively #a and #af1 the weight of the combined hydrogen will be #a_/h of the weight of the oxygen1 and the hydrogen available for combustion will be ,h - #a_/h ,o4 ,in complete combustion of the sulphur1 sulphur dioxide ,,so#b is formed1 which in solution in water forms sulphuric acid4 ,expressed numerically1 the theoretical amount of air for the above analysis is as follows3 #j4gdgi ,c #b-b_/c #a4iidd ,o needed 7 #j4jfdb 7 7 #j4jdih - -------7 ,h #h #j4cbfb ,o needed 7 #h 7 #j4jcbd ,s #a #j4jcbd ,o needed ------ ,total #b4cecj ,o needed ,one pound of oxygen is contained in #d4cb pounds of air4 ,the total air needed per pound of coal1 therefore1 will be #b4cec #d4cb #aj4afe4 ,the weight of combustible per pound of fuel is 4#gdgi 4#jdahbg 4#jcbd 4#jab 4#hc pounds1 and the air theoretically required per pound of combustible is #aj4afe 4#hc #ab4b pounds4 ,the above is equivalent to computing the theoretical amount of air required per pound of fuel by the formula3 7 ,o7 ,weight per pound #aa4eb ,c #cd4ef 7,h - -7 #d4cb ,s 7#aj7 7 #h7 where ,c1 ,h1 ,o and ,s are proportional parts by weight of carbon1 hydrogen1 oxygen and sulphur by ultimate analysis4 ,in practice it is impossible to obtain perfect combustion with the theoretical amount of air1 and an excess may be required1 amounting to sometimes double the theoretical supply1 depending upon the nature of the fuel to be burned and the method of burning it4 ,the reason for this is that it is impossible to bring each particle of oxygen in the air into intimate contact with the particles in the fuel that are to be oxidized1 due not only to the dilution of the oxygen in the air by nitrogen1 but because of such factors as the irregular thickness of the fire1 the varying resistance to the passage of the air through the fire in separate parts on account of ash1 clinker1 etc4 ,where the difficulties of drawing air uniformly through a fuel bed are eliminated1 as in the case of burning oil fuel or gas1 the air supply may be materially less than would be required for coal4 ,experiment has shown that coal will usually require #ej per cent more than the theoretical net calculated amount of air1 or about #ah pounds per pound of fuel either under natural or forced draft1 though this amount may vary widely with the type of furnace1 the nature of the coal1 and the method of firing4 ,if less than this amount of air is supplied1 the carbon burns to monoxide instead of dioxide and its full heat value is not developed4 ,an excess of air is also a source of waste1 as the products of combustion will be diluted and carry off an excessive amount of heat in the chimney gases1 or the air will so lower the temperature of the furnace gases as to delay the combustion to an extent that will cause carbon monoxide to pass off unburned from the furnace4 ,a sufficient amount of carbon monoxide in the gases may cause the action known as secondary combustion1 by igniting or mingling with air after leaving the furnace or in the flues or stack4 ,such secondary combustion which takes place either within the setting after leaving the furnace or in the flues or stack always leads to a loss of efficiency and1 in some instances1 leads to overheating of the flues and stack4 ,table #cb gives the theoretical amount of air required for various fuels calculated from formula 7#aj7 assuming the analyses of the fuels given in the table4 ,the process of combustion of different fuels and the effect of variation in the air supply for their combustion is treated in detail in the chapters dealing with the various fuels4 ,,table #cb ,,calculated ,,theoretical ,,amount ,,of ,,air ,,required ,,per ,,pound ,,of ,,various ,,fuels ,weight of ,constituents in ,one ,air ,required ,fuel ,pound ,dry ,fuel per ,pound of ,fuel ,carbon ,hydrogen ,oxygen ,pounds ,per ,cent ,per ,cent ,per ,cent ,coke #id4j 4 4 #aj4h ,anthracite ,coal #ia4e #c4e #b4f #aa4g ,bituminous ,coal #hg4j #e4j #d4j #aa4f ,lignite #gj4j #e4j #bj4j #h4i ,wood #ej4j #f4j #dc4e #f4j ,oil #he4j #ac4j #a4j #ad4c ,illustration3 #djfd ,,horse-,,power ,installation of ,babcock ,wilcox ,boilers and ,superheaters1 ,equipped with ,babcock ,wilcox ,chain ,grate ,stokers1 at the ,cosmopolitan ,electric ,co41 ,chicago1 ,ill4 ,,analysis ,,of ,,flue ,,gases ,the object of a flue gas analysis is the determination of the completeness of the combustion of the carbon in the fuel1 and the amount and distribution of the heat losses due to incomplete combustion4 ,the quantities actually determined by an analysis are the relative proportions by volume1 of carbon dioxide 7,,co#b71 oxygen 7,o71 and carbon monoxide 7,,co71 the determinations being made in this order4 ,the variations of the percentages of these gases in an analysis is best illustrated in the consideration of the complete combustion of pure carbon1 a pound of which requires #b4fg pounds of oxygen1#bh or #cb cubic feet at #fj degrees ,fahrenheit4 ,the gaseous product of such combustion will occupy1 when cooled1 the same volume as the oxygen1 namely1 #cb cubic feet4 ,the air supplied for the combustion is made up of #bj4ia per cent oxygen and #gi4ji per cent nitrogen by volume4 ,the carbon united with the oxygen in the form of carbon dioxide will have the same volume as the oxygen in the air originally supplied4 ,the volume of the nitrogen when cooled will be the same as in the air supplied1 as it undergoes no change4 ,hence for complete combustion of one pound of carbon1 where no excess of air is supplied1 an analysis of the products of combustion will show the following percentages by volume3 ,actual ,volume for ,one ,pound ,carbon ,per ,cent ,cubic ,feet by ,volume ,carbon ,dioxide #cb #bj4ia ,oxygen #j #j4jj ,nitrogen #aba #gi4ji --- ------ ,air required for one pound ,carbon #aec #ajj4jj ,for #ej per cent excess air the volume will be as follows3 #aec #a #bbi4e cubic feet of air per pound of carbon4 ,actual ,volume for ,one ,pound ,carbon ,per ,cent ,cubic ,feet by ,volume ,carbon ,dioxide #cb #ac4ia ,oxygen #af #g4jj #bj4ia per cent ,nitrogen #aha4e #gi4ji ----- ------ #bbi4e #ajj4jj ,for #ajj per cent excess air the volume will be as follows3 #aec #b #cjf cubic feet of air per pound of carbon4 ,actual ,volume for ,one ,pound ,carbon ,per ,cent ,cubic ,feet by ,volume ,carbon ,dioxide #cb #aj4de ,oxygen #cb #aj4de #bj4ia per cent ,nitrogen #bdb #gi4ji --- ------ #cjf #ajj4jj ,in each case the volume of oxygen which combines with the carbon is equal to 7cubic feet of air #bj4ia per cent7--#cb cubic feet4 ,it will be seen that no matter what the excess of air supplied1 the actual amount of carbon dioxide per pound of carbon remains the same1 while the percentage by volume decreases as the excess of air increases4 ,the actual volume of oxygen and the percentage by volume increases with the excess of air1 and the percentage of oxygen is1 therefore1 an indication of the amount of excess air4 ,in each case the sum of the percentages of ,,co#b and ,o is the same1 #bj4i4 ,although the volume of nitrogen increases with the excess of air1 its percentage by volume remains the same as it undergoes no change while combustion takes place2 its percentage for any amount of air excess1 therefore1 will be the same after combustion as before1 if cooled to the same temperature4 ,it must be borne in mind that the above conditions hold only for the perfect combustion of a pound of pure carbon4 ,carbon monoxide 7,,co7 produced by the imperfect combustion of carbon1 will occupy twice the volume of the oxygen entering into its composition and will increase the volume of the flue gases over that of the air supplied for combustion in the proportion of #ajj the per cent ,,co #a to ----------------------- #ajj ,when pure carbon is the fuel1 the sum of the percentages by volume of carbon dioxide1 oxygen and one-half of the carbon monoxide1 must be in the same ratio to the nitrogen in the flue gases as is the oxygen to the nitrogen in the air supplied1 that is1 #bj4ia to #gi4ji4 ,when burning coal1 however1 the percentage of nitrogen is obtained by subtracting the sum of the percentages by volume of the other gases from #ajj4 ,thus if an analysis shows #ab4e per cent ,,co#b1 #f4e per cent ,o1 and #j4f per cent ,,co1 the percentage of nitrogen which ordinarily is the only other constituent of the gas which need be considered1 is found as follows3 #ajj - 7#ab4e #f4e #j4f7 #hj4d per cent4 ,the action of the hydrogen in the volatile constituents of the fuel is to increase the apparent percentage of the nitrogen in the flue gases4 ,this is due to the fact that the water vapor formed by the combustion of the hydrogen will condense at a temperature at which the analysis is made1 while the nitrogen which accompanied the oxygen with which the hydrogen originally combined maintains its gaseous form and passes into the sampling apparatus with the other gases4 ,for this reason coals containing high percentages of volatile matter will produce a larger quantity of water vapor1 and thus increase the apparent percentage of nitrogen4 ,air ,required and ,supplied--,when the ultimate analysis of a fuel is known1 the air required for complete combustion with no excess can be found as shown in the chapter on combustion1 or from the following approximate formula3 ,pounds of air required per pound of fuel 7,c ,o ,s7 #cd4ef 7- 7,h - -7 -7#bi 7#aa7 7#c #h #h7 where ,c1 ,h and ,o equal the percentage by weight of carbon1 hydrogen and oxygen in the fuel divided by #ajj4 ,when the flue gas analysis is known1 the total1 amount of air supplied is3 ,pounds of air supplied per pound of fuel ,n #c4jcf 7-----------7 ,c#cj 7#ab7 ,,co#b ,,co where ,n1 ,,co#b and ,,co are the percentages by volume of nitrogen1 carbon dioxide and carbon monoxide in the flue gases1 and ,c the percentage by weight of carbon which is burned from the fuel and passes up the stack as flue gas4 ,this percentage of ,c which is burned must be distinguished from the percentage of ,c as found by an ultimate analysis of the fuel4 ,to find the percentage of ,c which is burned1 deduct from the total percentage of carbon as found in the ultimate analysis1 the percentage of unconsumed carbon found in the ash4 ,this latter quantity is the difference between the percentage of ash found by an analysis and that as determined by a boiler test4 ,it is usually assumed that the entire combustible element in the ash is carbon1 which assumption is practically correct4 ,thus if the ash in a boiler test were #af per cent and by an analysis contained #be per cent of carbon1 the percentage of unconsumed carbon would be #af 4#be #d per cent of the total coal burned4 ,if the coal contained by ultimate analysis #hj per cent of carbon the percentage burned1 and of which the products of combustion pass up the chimney would be #hj - #d #gf per cent1 which is the correct figure to use in calculating the total amount of air supplied by formula 7#ab74 ,the weight of flue gases resulting from the combustion of a pound of dry coal will be the sum of the weights of the air per pound of coal and the combustible per pound of coal1 the latter being equal to one minus the percentage of ash as found in the boiler test4 ,the weight of flue gases per pound of dry fuel may1 however1 be computed directly from the analyses1 as shown later1 and the direct computation is that ordinarily used4 ,the ratio of the air actually supplied per pound of fuel to that theoretically required to burn it is3 ,n #c4jcf7---------7;,c ,,co#b;,,co ------------------ 7#ac7 ,c ,o #cd4ef7- ,h - -7 #c #h in which the letters have the same significance as in formulae 7#aa7 and 7#ab74 ,the ratio of the air supplied per pound of combustible to the amount theoretically required is3 ,n ------------------ 7#ad7 ,n - #c4ghb7,o - ,,co7 which is derived as follows3 ,the ,n in the flue gas is the content of nitrogen in the whole amount of air supplied4 ,the oxygen in the flue gas is that contained in the air supplied and which was not utilized in combustion4 ,this oxygen was accompanied by #c4ghb times its volume of nitrogen4 ,the total amount of excess oxygen in the flue gases is 7,o - ,,co72 hence ,n - #c4ghb7,o - ,,co7 represents the nitrogen content in the air actually required for combustion and ,n 7,n - #c4ghb,o - ,,co7 is the ratio of the air supplied to that required4 ,this ratio minus one will be the proportion of excess air4 ,the heat lost in the flue gases is ,l #j4bd ,w 7,t - t7 7#ae7 ,where ,l ,b4 t4 u4 lost per pound of fuel1 ,w weight of flue gases in pounds per pound of dry coal1 ,t temperature of flue gases1 t temperature of atmosphere1 #j4bd specific heat of the flue gases4 ,the weight of flue gases1 ,w1 per pound of carbon can be computed directly from the flue gas analysis from the formula3 #aa ,,co#b #h ,o #g 7,,co ,n7 ---------------------------- 7#af7 #c 7,,co#b ,,co7 where ,,co#b1 ,o1 ,,co1 and ,n are the percentages by volume as determined by the flue gas analysis of carbon dioxide1 oxygen1 carbon monoxide and nitrogen4 ,the weight of flue gas per pound of dry coal will be the weight determined by this formula multiplied by the percentage of carbon in the coal from an ultimate analysis4 ,graph3 ,temperature of ,escaping ,gases--,deg4 ,fahr4 against ,heat carried away by ,chimney ,gases--,in ,b4t4u4 per pound of ,carbon burned4#ca ,fig4 #bj4 ,loss ,due to ,heat ,carried ,away by ,chimney ,gases for ,varying ,percentages of ,carbon ,dioxide4 ,based on ,boiler ,room ,temperature #hj ,degrees ,fahrenheit4 ,nitrogen in ,flue ,gas #hj4e ,per ,cent4 ,carbon ,monoxide in ,flue ,gas #j4 ,per ,cent ,fig4 #bj represents graphically the loss due to heat carried away by dry chimney gases for varying percentages of ,,co#b1 and different temperatures of exit gases4 ,the heat lost1 due to the fact that the carbon in the fuel is not completely burned and carbon monoxide is present in the flue gases1 in ,b4 t4 u4 per pound of fuel burned is3 7 ,,co 7 ,l' #aj1aej 7-----------7 7#ag7 7,,co ,,co#b7 where1 as before1 ,,co and ,,co#b are the percentages by volume in the flue gases and ,c is the proportion by weight of carbon which is burned and passes up the stack4 ,fig4 #ba represents graphically the loss due to such carbon in the fuel as is not completely burned but escapes up the stack in the form of carbon monoxide4 ,graph3 ,loss in ,b4,t4,u4 per ,pound of ,carbon ,burned#cb against ,per ,cent ,,co#b in ,flue ,gas ,fig4 #ba4 ,loss ,due to ,unconsumed ,carbon ,contained in the ,,co in the ,flue ,gases ,apparatus for ,flue ,gas ,analysis--,the ,orsat apparatus1 illustrated in ,fig4 #bb1 is generally used for analyzing flue gases4 ,the burette ,a is graduated in cubic centimeters up to #ajj1 and is surrounded by a water jacket to prevent any change in temperature from affecting the density of the gas being analyzed4 ,for accurate work it is advisable to use four pipettes1 ,b1 ,c1 ,d1 ,e1 the first containing a solution of caustic potash for the absorption of carbon dioxide1 the second an alkaline solution of pyrogallol for the absorption of oxygen1 and the remaining two an acid solution of cuprous chloride for absorbing the carbon monoxide4 ,each pipette contains a number of glass tubes1 to which some of the solution clings1 thus facilitating the absorption of the gas4 ,in the pipettes ,d and ,e1 copper wire is placed in these tubes to re-energize the solution as it becomes weakened4 ,the rear half of each pipette is fitted with a rubber bag1 one of which is shown at ,k1 to protect the solution from the action of the air4 ,the solution in each pipette should be drawn up to the mark on the capillary tube4 ,the gas is drawn into the burette through the ,u-tube ,h1 which is filled with spun glass1 or similar material1 to clean the gas4 ,to discharge any air or gas in the apparatus1 the cock ,g is opened to the air and the bottle ,f is raised until the water in the burette reaches the #ajj cubic centimeters mark4 ,the cock ,g is then turned so as to close the air opening and allow gas to be drawn through ,h1 the bottle ,f being lowered for this purpose4 ,the gas is drawn into the burette to a point below the zero mark1 the cock ,g then being opened to the air and the excess gas expelled until the level of the water in ,f and in ,a are at the zero mark4 ,this operation is necessary in order to obtain the zero reading at atmospheric pressure4 ,the apparatus should be carefully tested for leakage as well as all connections leading thereto4 ,simple tests can be made2 for example3 ,if after the cock ,g is closed1 the bottle ,f is placed on top of the frame for a short time and again brought to the zero mark1 the level of the water in ,a is above the zero mark1 a leak is indicated4 ,illustration3 ,fig4 #bb4 ,orsat ,apparatus ,before taking a final sample for analysis1 the burette ,a should be filled with gas and emptied once or twice1 to make sure that all the apparatus is filled with the new gas4 ,the cock ,g is then closed and the cock ,i in the pipette ,b is opened and the gas driven over into ,b by raising the bottle ,f4 ,the gas is drawn back into ,a by lowering ,f and when the solution in ,b has reached the mark in the capillary tube1 the cock ,i is closed and a reading is taken on the burette1 the level of the water in the bottle ,f being brought to the same level as the water in ,a4 ,the operation is repeated until a constant reading is obtained1 the number of cubic centimeters being the percentage of ,,co#b in the flue gases4 ,the gas is then driven over into the pipette ,c and a similar operation is carried out4 ,the difference between the resulting reading and the first reading gives the percentage of oxygen in the flue gases4 ,the next operation is to drive the gas into the pipette ,d1 the gas being given a final wash in ,e1 and then passed into the pipette ,c to neutralize any hydrochloric acid fumes which may have been given off by the cuprous chloride solution1 which1 especially if it be old1 may give off such fumes1 thus increasing the volume of the gases and making the reading on the burette less than the true amount4 ,the process must be carried out in the order named1 as the pyrogallol solution will also absorb carbon dioxide1 while the cuprous chloride solution will also absorb oxygen4 ,as the pressure of the gases in the flue is less than the atmospheric pressure1 they will not of themselves flow through the pipe connecting the flue to the apparatus4 ,the gas may be drawn into the pipe in the way already described for filling the apparatus1 but this is a tedious method4 ,for rapid work a rubber bulb aspirator connected to the air outlet of the cock ,g will enable a new supply of gas to be drawn into the pipe1 the apparatus then being filled as already described4 ,another form of aspirator draws the gas from the flue in a constant stream1 thus insuring a fresh supply for each sample4 ,the analysis made by the ,orsat apparatus is volumetric2 if the analysis by weight is required1 it can be found from the volumetric analysis as follows3 ,multiply the percentages by volume by either the densities or the molecular weight of each gas1 and divide the products by the sum of all the products2 the quotients will be the percentages by weight4 ,for most work sufficient accuracy is secured by using the even values of the molecular weights4 ,the even values of the molecular weights of the gases appearing in an analysis by an ,orsat are3 ,carbon ,dioxide #dd ,carbon ,monoxide #bh ,oxygen #cb ,nitrogen #bh ,table #cc indicates the method of converting a volumetric flue gas analysis into an analysis by weight4 ,,table #cc ,,conversion ,,of ,a ,,flue ,,gas ,,analysis ,,by ,,volume ,,to ,,one ,,by ,,weight ,column ,headings3 ,a3 ,analysis by ,volume ,per ,cent ,b3 ,molecular ,weight ,c3 ,volume times ,molecular ,weight ,d3 ,analysis by ,weight ,per ,cent ,gas ,a ,b ,c ,d #ecf4h ,carbon ,dioxide ,,co#b #ab4b #ab7baf7 #ecf4h ------ #ag4g #cjbb4h #aa4b ,carbon ,monoxide ,,co 4#d #abaf #aa4b ------ 4#d #cjbb4h #bbj4h ,oxygen ,o #f4i #baf #bbj4h ------ #g4c #cjbb4h #bbed4j ,nitrogen ,n #hj4e #bad #bbed4j ------ #gd4f #cjbb4h ,total #ajj4j #cjbb4h #ajj4j ,application of ,formulae and ,rules--,pocahontas coal is burned in the furnace1 a partial ultimate analysis being3 ,per ,cent ,carbon #hb4a ,hydrogen #d4be ,oxygen #b4f ,sulphur #a4f ,ash #f4j ,b4 t4 u41 per pound dry #adejj ,the flue gas analysis shows3 ,per ,cent ,,co#b #aj4g ,o #i4j ,,co #j4j ,n 7by difference7 #hj4c ,determine3 ,the flue gas analysis by weight 7see ,table #cc71 the amount of air required for perfect combustion1 the actual weight of air per pound of fuel1 the weight of flue gas per pound of coal1 the heat lost in the chimney gases if the temperature of these is #ejj degrees ,fahrenheit1 and the ratio of the air supplied to that theoretically required4 ,solution3 ,the theoretical weight of air required for perfect combustion1 per pound of fuel1 from formula 7#aa7 will be1 74#hba 4#jbf 4#jaf7 ,w #cd4ef 7---- 74#jdbe - ----7 ----7 #aj4hh pounds4 7 #c #h #h 7 ,if the amount of carbon which is burned and passes away as flue gas is #hj per cent1 which would allow for #b4a per cent of unburned carbon in terms of the total weight of dry fuel burned1 the weight of dry gas per pound of carbon burned will be from formula 7#af73 #aa #aj4g #h #i4j #g7j #hj4c7 ,w --------------------------------- #bc4db pounds #c7aj4g #j7 and the weight of flue gas per pound of coal burned will be 4#hj #bc4db #ah4gd pounds4 ,the heat lost in the flue gases per pound of coal burned will be from formula 7#ae7 and the value #ah4gd just determined4 ,loss 4#bd #ah4gd 7#ejj - #fj7 #aigi ,b4 t4 u4 ,the percentage of heat lost in the flue gases will be #aigi #adejj #ac4f per cent4 ,the ratio of air supplied per pound of coal to that theoretically required will be #ah4gd #aj4hh #a4gb per cent4 ,the ratio of air supplied per pound of combustible to that required will be from formula 7#ad73 4#hjc ------------------------- #a4gc 4#hjc - #c4ghb74ji - #j7 ,the ratio based on combustible will be greater than the ratio based on fuel if there is unconsumed carbon in the ash4 ,unreliability of ,,co#b ,readings ,taken ,alone--,it is generally assumed that high ,,co#b readings are indicative of good combustion and hence of high efficiency4 ,this is true only in the sense that such high readings do indicate the small amount of excess air that usually accompanies good combustion1 and for this reason high ,,co#b readings alone are not considered entirely reliable4 ,wherever an automatic ,,co#b recorder is used1 it should be checked from time to time and the analysis carried further with a view to ascertaining whether there is ,,co present4 ,as the percentage of ,,co#b in these gases increases1 there is a tendency toward the presence of ,,co1 which1 of course1 cannot be shown by a ,,co#b recorder1 and which is often difficult to detect with an ,orsat apparatus4 ,the greatest care should be taken in preparing the cuprous chloride solution in making analyses and it must be known to be fresh and capable of absorbing ,,co4 ,in one instance that came to our attention1 in using an ,orsat apparatus where the cuprous chloride solution was believed to be fresh1 no ,,co was indicated in the flue gases but on passing the same sample into a ,hempel apparatus1 a considerable percentage was found4 ,it is not safe1 therefore1 to assume without question from a high ,,co#b reading that the combustion is correspondingly good1 and the question of excess air alone should be distinguished from that of good combustion4 ,the effect of a small quantity of ,,co1 say one per cent1 present in the flue gases will have a negligible influence on the quantity of excess air1 but the presence of such an amount would mean a loss due to the incomplete combustion of the carbon in the fuel of possibly #d4e per cent of the total heat in the fuel burned4 ,when this is considered1 the importance of a complete flue gas analysis is apparent4 ,table #cd gives the densities of various gases together with other data that will be of service in gas analysis work4 ,,table #cd ,,density ,,of ,,gases ,,at #cb ,,degrees ,,fahrenheit ,,and ,,atmospheric ,,pressure ,,adapted ,,from ,,smithsonian ,,tables ---------------------------------------- ---------------------- ,relative ,weight ,density1 of ,volume ,hydrogen #a ,specific,one ,cubic of -------------- ,gas ,chemical ,gravity ,foot ,one ,pound ,approx- ,symbol ,air#a ,pounds ,cubic ,feet ,exact imate ---------------------------------------- --------------------- ,oxygen ,o #a4jec 4#jhibb #aa4bjh #ae4hg #af ,nitrogen ,n #j4ifgc 4#jghbi #ab4ggc #ac4ib #ad ,hydrogen ,h #j4jfif 4#jjefba #agg4ij #a4jj #a ,carbon ,dioxide ,,co#b #a4ebia 4#abbfi #h4aea #ba4hc #bb ,carbon ,monoxide ,,co #j4ifgb 4#jghjg #ab4hji #ac4hi #ad ,methane ,,ch#d #j4eegf 4#jddgj #bb4cga #g4ie #h ,ethane ,c#b;,h#f #a4jge 4#jhcgi #aa4ice #ad4ia #ae ,acetylene ,c#b;,h#b #j4ibj 4#jgbed #ac4ghe #ab4ia #ac ,sulphur ,dioxide ,,so#b #b4bfci 4#aghfb #e4eih #ca4if #cb ,air 444 #a4jjjj 4#jhjga #ab4cij 444 444 ---------------------------------------- --------------------- ,illustration3 #aidb ,horse-power ,installation of ,babcock ,wilcox ,boilers and ,superheaters in the ,singer ,building1 ,new ,york ,city ,,classification ,,of ,,fuels 7,,with ,,particular ,,reference ,,to ,,coal7 ,fuels for steam boilers may be classified as solid1 liquid or gaseous4 ,of the solid fuels1 anthracite and bituminous coals are the most common1 but in this class must also be included lignite1 peat1 wood1 bagasse and the refuse from certain industrial processes such as sawdust1 shavings1 tan bark and the like4 ,straw1 corn and coffee husks are utilized in isolated cases4 ,the class of liquid fuels is represented chiefly by petroleum1 though coal tar and water-gas tar are used to a limited extent4 ,gaseous fuels are limited to natural gas1 blast furnace gas and coke oven gas1 the first being a natural product and the two latter by-products from industrial processes4 ,though waste gases from certain processes may be considered as gaseous fuels1 inasmuch as the question of combustion does not enter1 the methods of utilizing them differ from that for combustible gaseous fuel1 and the question will be dealt with separately4 ,since coal is by far the most generally used of all fuels1 this chapter will be devoted entirely to the formation1 composition and distribution of the various grades1 from anthracite to peat4 ,the other fuels will be discussed in succeeding chapters and their combustion dealt with in connection with their composition4 ,formation of ,coal--,all coals are of vegetable origin and are the remains of prehistoric forests4 ,destructive distillation due to great pressures and temperatures1 has resolved the organic matter into its invariable ultimate constituents1 carbon1 hydrogen1 oxygen and other substances1 in varying proportions4 ,the factors of time1 depth of beds1 disturbance of beds and the intrusion of mineral matter resulting from such disturbances have produced the variation in the degree of evolution from vegetable fiber to hard coal4 ,this variation is shown chiefly in the content of carbon1 and ,table #ce shows the steps of such variation4 ,,table #ce ,,approximate ,,chemical ,,changes ,,from ,,wood ,,fiber ,,to ,,anthracite ,,coal ---------------------------------------- ---- ,substance ,carbon ,hydrogen,oxygen ---------------------------------------- ---- ,wood ,fiber #eb4fe #e4be #db4aj ,peat #ei4eg #e4if #cd4dg ,lignite #ff4jd #e4bg #bh4fi ,earthy ,brown ,coal #gc4ah #e4fh #ba4ad ,bituminous ,coal #ge4jf #e4hd #ai4aj ,semi-bituminous ,coal #hi4bi #e4je #e4ff ,anthracite ,coal #ia4eh #c4if #d4df ---------------------------------------- ---- ,composition of ,coal--,the uncombined carbon in coal is known as fixed carbon4 ,some of the carbon constituent is combined with hydrogen and this1 together with other gaseous substances driven off by the application of heat1 form that portion of the coal known as volatile matter4 ,the fixed carbon and the volatile matter constitute the combustible4 ,the oxygen and nitrogen contained in the volatile matter are not combustible1 but custom has applied this term to that portion of the coal which is dry and free from ash1 thus including the oxygen and nitrogen4 ,the other important substances entering into the composition of coal are moisture and the refractory earths which form the ash4 ,the ash varies in different coals from #c to #cj per cent and the moisture from #j4ge to #de per cent of the total weight of the coal1 depending upon the grade and the locality in which it is mined4 ,a large percentage of ash is undesirable as it not only reduces the calorific value of the fuel1 but chokes up the air passages in the furnace and through the fuel bed1 thus preventing the rapid combustion necessary to high efficiency4 ,if the coal contains an excessive quantity of sulphur1 trouble will result from its harmful action on the metal of the boiler where moisture is present1 and because it unites with the ash to form a fusible slag or clinker which will choke up the grate bars and form a solid mass in which large quantities of unconsumed carbon may be imbedded4 ,moisture in coal may be more detrimental than ash in reducing the temperature of a furnace1 as it is non-combustible1 absorbs heat both in being evaporated and superheated to the temperature of the furnace gases4 ,in some instances1 however1 a certain amount of moisture in a bituminous coal produces a mechanical action that assists in the combustion and makes it possible to develop higher capacities than with dry coal4 ,classification of ,coal--,custom has classified coals in accordance with the varying content of carbon and volatile matter in the combustible4 ,table #cf gives the approximate percentages of these constituents for the general classes of coals with the corresponding heat values per pound of combustible4 ,,table #cf ,,approximate ,,composition ,,and ,,calorific ,,value ,,of ,,general ,,grades ,,of ,,coal ,,on ,,basis ,,of ,,combustible ---------------------------------------- --------------------- ,kind of ,coal ,per ,cent of ,combustible ,b4 t4 u4 --------------------------- ,per ,pound of ,fixed ,carbon,volatile ,matter ,combustible ---------------------------------------- -------------------- ,anthracite #ig4j to #ib4e #c4j to #g4e #adfjj to #adhjj ,semi-anthracite #ib4e to #hg4e #g4e to #ab4e #adgjj to #aeejj ,semi-bituminous #hg4e to #ge4j #ab4e to #be4j #aeejj to #afjjj ,bituminous--,eastern#ge4j to #fj4j #be4j to #dj4j #adhjj to #aecjj ,bituminous--,western#fe4j to #ej4j #ce4j to #ej4j #acejj to #adhjj ,lignite ,under #ej ,over #ej #aajjj to #acejj ---------------------------------------- -------------------- ,anthracite--,the name anthracite1 or hard coal1 is applied to those dry coals containing from #c to #g per cent volatile matter and which do not swell when burned4 ,true anthracite is hard1 compact1 lustrous and sometimes iridescent1 and is characterized by few joints and clefts4 ,its specific gravity varies from #a4d to #a4h4 ,in burning1 it kindles slowly and with difficulty1 is hard to keep alight1 and burns with a short1 almost colorless flame1 without smoke4 ,semi-anthracite coal has less density1 hardness and luster than true anthracite1 and can be distinguished from it by the fact that when newly fractured it will soot the hands4 ,its specific gravity is ordinarily about #a4d4 ,it kindles quite readily and burns more freely than the true anthracites4 ,semi-bituminous coal is softer than anthracite1 contains more volatile hydrocarbons1 kindles more easily and burns more rapidly4 ,it is ordinarily free burning1 has a high calorific value and is of the highest order for steam generating purposes4 ,bituminous coals are still softer than those described and contain still more volatile hydrocarbons4 ,the difference between the semi-bituminous and the bituminous coals is an important one1 economically4 ,the former have an average heating value per pound of combustible about #f per cent higher than the latter1 and they burn with much less smoke in ordinary furnaces4 ,the distinctive characteristic of the bituminous coals is the emission of yellow flame and smoke when burning4 ,in color they range from pitch black to dark brown1 having a resinous luster in the most compact specimens1 and a silky luster in such specimens as show traces of vegetable fiber4 ,the specific gravity is ordinarily about #a4c4 ,bituminous coals are either of the caking or non-caking class4 ,the former1 when heated1 fuse and swell in size2 the latter burn freely1 do not fuse1 and are commonly known as free burning coals4 ,caking coals are rich in volatile hydrocarbons and are valuable in gas manufacture4 ,bituminous coals absorb moisture from the atmosphere4 ,the surface moisture can be removed by ordinary drying1 but a portion of the water can be removed only by heating the coal to a temperature of about #bej degrees ,fahrenheit4 ,cannel coal is a variety of bituminous coal1 rich in hydrogen and hydrocarbons1 and is exceedingly valuable as a gas coal4 ,it has a dull resinous luster and burns with a bright flame without fusing4 ,cannel coal is seldom used for steam coal1 though it is sometimes mixed with semi-bituminous coal where an increased economy at high rates of combustion is desired4 ,the composition of cannel coal is approximately as follows3 fixed carbon1 #bf to #ee per cent2 volatile matter1 #db to #fd per cent2 earthy matter1 #b to #ad per cent4 ,its specific gravity is approximately #a4bd4 ,lignite is organic matter in the earlier stages of its conversion into coal1 and includes all varieties which are intermediate between peat and coal of the older formation4 ,its specific gravity is low1 being #a4b to #a4bc1 and when freshly mined it may contain as high as #ej per cent of moisture4 ,its appearance varies from a light brown1 showing a distinctly woody structure1 in the poorer varieties1 to a black1 with a pitchy luster resembling hard coal1 in the best varieties4 ,it is non-caking and burns with a bright but slightly smoky flame with moderate heat4 ,it is easily broken1 will not stand much handling in transportation1 and if exposed to the weather will rapidly disintegrate1 which will increase the difficulty of burning it4 ,its composition varies over wide limits4 ,the ash may run as low as one per cent and as high as #ej per cent4 ,its high content of moisture and the large quantity of air necessary for its combustion cause large stack losses4 ,it is distinctly a low-grade fuel and is used almost entirely in the districts where mined1 due to its cheapness4 ,peat is organic matter in the first stages of its conversion into coal and is found in bogs and similar places4 ,its moisture content when cut is extremely high1 averaging #ge or #hj per cent4 ,it is unsuitable for fuel until dried and even then will contain as much as #cj per cent moisture4 ,its ash content when dry varies from #c to #ab per cent4 ,in this country1 though large deposits of peat have been found1 it has not as yet been found practicable to utilize it for steam generating purposes in competition with coal4 ,in some ,european countries1 however1 the peat industry is common4 ,distribution--,the anthracite coals are1 with some unimportant exceptions1 confined to five small fields in ,eastern ,pennsylvania1 as shown in the following list4 ,these fields are given in the order of their hardness4 ,lehigh or ,eastern ,middle ,field ,green ,mountain ,district ,black ,creek ,district ,hazelton ,district ,beaver ,meadow ,district ,panther ,creek ,district#cc ,mahanoy or ,western ,field#cd ,east ,mahanoy ,district ,west ,mahanoy ,district ,wyoming or ,northern ,field ,carbondale ,district ,scranton ,district ,pittston ,district ,wilkesbarre ,district ,plymouth ,district ,schuylkill or ,southern ,field ,east ,schuylkill ,district ,west ,schuylkill ,district ,louberry ,district ,lykens ,valley or ,southwestern ,field ,lykens ,valley ,district ,shamokin ,district#ce ,anthracite is also found in ,pulaski and ,wythe ,counties1 ,virginia2 along the border of ,little ,walker ,mountain1 and in ,gunnison ,county1 ,colorado4 ,the areas in ,virginia are limited1 however1 while in ,colorado the quality varies greatly in neighboring beds and even in the same bed4 ,an anthracite bed in ,new ,mexico was described in #ahgj by ,dr4 ,r4 ,w4 ,raymond1 formerly ,united ,states ,mining ,commissioner4 ,semi-anthracite coals are found in a few small areas in the western part of the anthracite field4 ,the largest of these beds is the ,bernice in ,sullivan ,county1 ,pennsylvania4 ,mr4 ,william ,kent1 in his ,steam ,boiler ,economy1 describes this as follows3 ,the ,bernice semi-anthracite coal basin lies between ,beech ,creek on the north and ,loyalsock ,creek on the south4 ,it is six miles long1 east and west1 and hardly a third of a mile across4 ,an #h-;foot vein of coal lies in a bed of #ab feet of coal and slate4 ,the coal of this bed is the dividing line between anthracite and semi-anthracite1 and is similar to the coal of the ,lykens ,valley ,district4 ,mine analyses give a range as follows3 moisture1 #j4fe to #a4ig2 volatile matter1 #c4ef to #i4dj2 fixed carbon1 #hb4eb to #hi4ci2 ash1 #c4bg to #i4cd2 sulphur1 #j4bd to #a4jd4 ,semi-bituminous coals are found on the eastern edge of the great ,appalachian ,field4 ,starting with ,tioga and ,bradford ,counties of northern ,pennsylvania1 the bed runs southwest through ,lycoming1 ,clearfield1 ,centre1 ,huntingdon1 ,cambria1 ,somerset and ,fulton ,counties1 ,pennsylvania2 ,allegheny ,county1 ,maryland2 ,buchannan1 ,dickinson1 ,lee1 ,russell1 ,scott1 ,tazewell and ,wise ,counties1 ,virginia2 ,mercer1 ,mc,dowell1 ,fayette1 ,raleigh and ,mineral ,counties1 ,west ,virginia2 and ending in northeastern ,tennessee1 where a small amount of semi-bituminous is mined4 ,the largest of the bituminous fields is the ,appalachian4 ,beginning near the northern boundary of ,pennsylvania1 in the western portion of the ,state1 it extends southwestward through ,west ,virginia1 touching ,maryland and ,virginia on their western borders1 passing through southeastern ,ohio1 eastern ,kentucky and central ,tennessee1 and ending in western ,alabama1 #ijj miles from its northern extremity4 ,the next bituminous coal producing region to the west is the ,northern ,field1 in north central ,michigan4 ,still further to the west1 and second in importance to the ,appalachian ,field1 is the ,eastern ,interior ,field4 ,this covers1 with the exception of the upper northern portion1 nearly the entire ,state of ,illinois1 southwest ,indiana and the western portion of ,kentucky4 ,the ,western ,field extends through central and southern ,iowa1 western ,missouri1 southwestern ,kansas1 eastern ,oklahoma and the west central portion of ,arkansas4 ,the ,southwestern ,field is confined entirely to the north central portion of ,texas1 in which ,state there are also two small isolated fields along the ,rio ,grande ,river4 ,the remaining bituminous fields are scattered through what may be termed the ,rocky ,mountain ,region1 extending from ,montana to ,new ,orleans4 ,a partial list of these fields and their location follows3 ,judith ,basin ,central ,montana ,bull ,mountain ,field ,central ,montana ,yellowstone ,region ,southwestern ,montana ,big ,horn ,basin ,region ,southern ,montana ,big ,horn ,basin ,region ,northern ,wyoming ,black ,hills ,region ,northeastern ,wyoming ,hanna ,field ,southern ,wyoming ,green ,river ,region ,southwestern ,wyoming ,yampa ,field ,northwestern ,colorado ,north ,park ,field ,northern ,colorado ,denver ,region ,north ,central ,colorado ,uinta ,region ,western ,colorado ,uinta ,region ,eastern ,utah ,southwestern ,region ,southwestern ,utah ,raton ,mountain ,region ,southern ,colorado ,raton ,mountain ,region ,northern ,new ,mexico ,san ,juan ,river ,region ,northwestern ,new ,mexico ,capitan ,field ,southern ,new ,mexico ,along the ,pacific ,coast a few small fields are scattered in western ,california1 southwestern ,oregon1 western and northwestern ,washington4 ,most of the coals in the above fields are on the border line between bituminous and lignite4 ,they are really a low grade of bituminous coal and are known as sub-bituminous or black lignites4 ,lignites--,these resemble the brown coals of ,europe and are found in the western states1 ,wyoming1 ,new ,mexico1 ,arizona1 ,utah1 ,montana1 ,north ,dakota1 ,nevada1 ,california1 ,oregon and ,washington4 ,many of the fields given as those containing bituminous coals in the western states also contain true lignite4 ,lignite is also found in the eastern part of ,texas and in ,oklahoma4 ,alaska ,coals--,coal has been found in ,alaska and undoubtedly is of great value1 though the extent and character of the fields have probably been exaggerated4 ,great quantities of lignite are known to exist1 and in quality the coal ranges in character from lignite to anthracite4 ,there are at present1 however1 only two fields of high-grade coals known1 these being the ,bering ,river ,field1 near ,controllers ,bay1 and the ,matanuska ,field1 at the head of ,cooks ,inlet4 ,both of these fields are known to contain both anthracite and high-grade bituminous coals1 though as yet they cannot be said to have been opened up4 ,weathering of ,coal--,the storage of coal has become within the last few years to a certain extent a necessity due to market conditions1 danger of labor difficulties at the mines and in the railroads1 and the crowding of transportation facilities4 ,the first cause is probably the most important1 and this is particularly true of anthracite coals where a sliding scale of prices is used according to the season of the year4 ,while market conditions serve as one of the principal reasons for coal storage1 most power plants and manufacturing plants feel compelled to protect their coal supply from the danger of strikes1 car shortages and the like1 and it is customary for large power plants1 railroads and coal companies themselves1 to store bituminous coal4 ,naval coaling stations are also an example of what is done along these lines4 ,anthracite is the nearest approach to the ideal coal for storing4 ,it is not subject to spontaneous ignition1 and for this reason is unlimited in the amount that may be stored in one pile4 ,with bituminous coals1 however1 the case is different4 ,most bituminous coals will ignite if placed in large enough piles and all suffer more or less from disintegration4 ,coal producers only store such coals as are least liable to ignite1 and which will stand rehandling for shipment4 ,the changes which take place in stored coal are of two kinds3 #ast1 the oxidization of the inorganic matter such as pyrites2 and #bnd1 the direct oxidization of the organic matter of the actual coal4 ,the first change will result in an increased volume of the coal1 and sometimes in an increased weight1 and a marked disintegration4 ,the changes due to direct oxidization of the coal substances usually cannot be detected by the eye1 but as they involve the oxidization of the carbon and available hydrogen and the absorption of the oxygen by unsaturated hydrocarbons1 they are the chief cause of the weathering losses in heat value4 ,numerous experiments have led to the conclusion that this is also the cause for spontaneous combustion4 ,experiments to show loss in calorific heat values due to weathering indicate that such loss may be as high as #aj per cent when the coal is stored in the air1 and #h4ge per cent when stored under water4 ,it would appear that the higher the volatile content of the coal1 the greater will be the loss in calorific value and the more subject to spontaneous ignition4 ,some experiments made by ,messrs4 ,s4 ,w4 ,parr and ,w4 ,f4 ,wheeler1 published in #aiji by the ,experiment ,station of the ,university of ,illinois1 indicate that coals of the nature found in ,illinois and neighboring states are not affected seriously during storage from the standpoint of weight and heating value1 the latter loss averaging about #c per cent for the first year of storage4 ,they found that the losses due to disintegration and to spontaneous ignition were of greater importance4 ,their conclusions agree with those deduced from the other experiments1 viz41 that the storing of a larger size coal than that which is to be used1 will overcome to a certain extent the objection to disintegration1 and that the larger sizes1 besides being advantageous in respect to disintegration1 are less liable to spontaneous ignition4 ,storage under water will1 of course1 entirely prevent any fire loss and1 to a great extent1 will stop disintegration and reduce the calorific losses to a minimum4 ,to minimize the danger of spontaneous ignition in storing coal1 the piles should be thoroughly ventilated4 ,pulverized ,fuels--,considerable experimental work has been done with pulverized coal1 utilizing either coal dust or pulverizing such coal as is too small to be burned in other ways4 ,if satisfactorily fed to the furnace1 it would appear to have several advantages4 ,the dust burned in suspension would be more completely consumed than is the case with the solid coals1 the production of smoke would be minimized1 and the process would admit of an adjustment of the air supply to a point very close to the amount theoretically required4 ,this is due to the fact that in burning there is an intimate mixture of the air and fuel4 ,the principal objections have been in the inability to introduce the pulverized fuel into the furnace uniformly1 the difficulty of reducing the fuel to the same degree of fineness1 liability of explosion in the furnace due to improper mixture with the air1 and the decreased capacity and efficiency resulting from the difficulty of keeping tube surfaces clean4 ,pressed ,fuels--,in this class are those composed of the dust of some suitable combustible1 pressed and cemented together by a substance possessing binding and in most cases inflammable properties4 ,such fuels1 known as briquettes1 are extensively used in foreign countries and consist of carbon or soft coal1 too small to be burned in the ordinary way1 mixed usually with pitch or coal tar4 ,much experimenting has been done in this country in briquetting fuels1 the government having taken an active interest in the question1 but as yet this class of fuel has not come into common use as the cost and difficulty of manufacture and handling have made it impossible to place it in the market at a price to successfully compete with coal4 ,coke is a porous product consisting almost entirely of carbon remaining after certain manufacturing processes have distilled off the hydrocarbon gases of the fuel used4 ,it is produced1 first1 from gas coal distilled in gas retorts2 second1 from gas or ordinary bituminous coals burned in special furnaces called coke ovens2 and third1 from petroleum by carrying the distillation of the residuum to a red heat4 ,coke is a smokeless fuel4 ,it readily absorbs moisture from the atmosphere and if not kept under cover its moisture content may be as much as #bj per cent of its own weight4 ,gas-house coke is generally softer and more porous than oven coke1 ignites more readily1 and requires less draft for its combustion4 ,illustration3 #af1jjj ,horse-power ,installation of ,babcock ,wilcox ,boilers and ,superheaters at the ,brunot's ,island ,plant of the ,duquesne ,light ,co41 ,pittsburgh1 ,pa4 ,,the ,,determination ,,of ,,heating ,,values ,,of ,,fuels ,the heating value of a fuel may be determined either by a calculation from a chemical analysis or by burning a sample in a calorimeter4 ,in the former method the calculation should be based on an ultimate analysis1 which reduces the fuel to its elementary constituents of carbon1 hydrogen1 oxygen1 nitrogen1 sulphur1 ash and moisture1 to secure a reasonable degree of accuracy4 ,a proximate analysis1 which determines only the percentage of moisture1 fixed carbon1 volatile matter and ash1 without determining the ultimate composition of the volatile matter1 cannot be used for computing the heat of combustion with the same degree of accuracy as an ultimate analysis1 but estimates may be based on the ultimate analysis that are fairly correct4 ,an ultimate analysis requires the services of a competent chemist1 and the methods to be employed in such a determination will be found in any standard book on engineering chemistry4 ,an ultimate analysis1 while resolving the fuel into its elementary constituents1 does not reveal how these may have been combined in the fuel4 ,the manner of their combination undoubtedly has a direct effect upon their calorific value1 as fuels having almost identical ultimate analyses show a difference in heating value when tested in a calorimeter4 ,such a difference1 however1 is slight1 and very close approximations may be computed from the ultimate analysis4 ,ultimate analyses are given on both a moist and a dry fuel basis4 ,inasmuch as the latter is the basis generally accepted for the comparison of data1 it would appear that it is the best basis on which to report such an analysis4 ,when an analysis is given on a moist fuel basis it may be readily converted to a dry basis by dividing the percentages of the various constituents by one minus the percentage of moisture1 reporting the moisture content separately4 ,moist ,fuel ,dry ,fuel ,c #hc4ie #hd4de ,h #d4bc #d4be ,o #c4jb #c4jd ,n #a4bg #a4bh ,s 4#ia 4#ia ,ash #f4jc #f4jg ------ #ajj4jj ,moisture 4#ei 4#ei ------ #ajj4jj ,calculations from an ,ultimate ,analysis--,the first formula for the calculation of heating values from the composition of a fuel as determined from an ultimate analysis is due to ,dulong1 and this formula1 slightly modified1 is the most commonly used to-day4 ,other formulae have been proposed1 some of which are more accurate for certain specific classes of fuel1 but all have their basis in ,dulong's formula1 the accepted modified form of which is3 ,heat units in ,b4 t4 u4 per pound of dry fuel ,o #ad1fjj ,c #fb1jjj7;,h - -7 #djjj ,s 7#ah7 #h where ,c1 ,h1 ,o and ,s are the proportionate parts by weight of carbon1 hydrogen1 oxygen and sulphur4 ,assume a coal of the composition given4 ,substituting in this formula 7#ah71 ,heating value per pound of dry coal 7 4#jcjd7 #ad1fjj 4#hdde #fb1jjj 74#jdbe - -----7 #djjj 4#jjia #ad1gfe ,b4 t4 u4 7 #h 7 ,this coal1 by a calorimetric test1 showed #ad1hdc ,b4 t4 u41 and from a comparison the degree of accuracy of the formula will be noted4 ,the investigation of ,lord and ,haas in this country1 ,mabler in ,france1 and ,bunte in ,germany1 all show that ,dulong's formula gives results nearly identical with those obtained from calorimetric tests and may be safely applied to all solid fuels except cannel coal1 lignite1 turf and wood1 provided the ultimate analysis is correct4 ,this practically limits its use to coal4 ,the limiting features are the presence of hydrogen and carbon united in the form of hydrocarbons4 ,such hydrocarbons are present in coals in small quantities1 but they have positive and negative heats of combination1 and in coals these appear to offset each other1 certainly sufficiently to apply the formula to such fuels4 ,high and ,low ,heat ,value of ,fuels--,in any fuel containing hydrogen the calorific value as found by the calorimeter is higher than that obtainable under most working conditions in boiler practice by an amount equal to the latent heat of the volatilization of water4 ,this heat would reappear when the vapor was condensed1 though in ordinary practice the vapor passes away uncondensed4 ,this fact gives rise to a distinction in heat values into the so-called higher and lower calorific values4 ,the higher value1 i4 e41 the one determined by the calorimeter1 is the only scientific unit1 is the value which should be used in boiler testing work1 and is the one recommended by the ,american ,society of ,mechanical ,engineers4 ,there is no absolute measure of the lower heat of combustion1 and in view of the wide difference in opinion among physicists as to the deductions to be made from the higher or absolute unit in this determination1 the lower value must be considered an artificial unit4 ,the lower value entails the use of an ultimate analysis and involves assumptions that would make the employment of such a unit impracticable for commercial work4 ,the use of the low value may also lead to error and is in no way to be recommended for boiler practice4 ,an example of its illogical use may be shown by the consideration of a boiler operated in connection with a special economizer where the vapor produced by hydrogen is partially condensed by the economizer4 ,if the low value were used in computing the boiler efficiency1 it is obvious that the total efficiency of the combined boiler and economizer must be in error through crediting the combination with the heat imparted in condensing the vapor and not charging such heat to the heat value of the coal4 ,heating ,value of ,gaseous ,fuels--,the method of computing calorific values from an ultimate analysis is particularly adapted to solid fuels1 with the exceptions already noted4 ,the heating value of gaseous fuels may be calculated by ,dulong's formula provided another term is added to provide for any carbon monoxide present4 ,such a method1 however1 involves the separating of the constituent gases into their elementary gases1 which is oftentimes difficult and liable to simple arithmetical error4 ,as the combustible portion of gaseous fuels is ordinarily composed of hydrogen1 carbon monoxide and certain hydrocarbons1 a determination of the calorific value is much more readily obtained by a separation into their constituent gases and a computation of the calorific value from a table of such values of the constituents4 ,table #cg gives the calorific value of the more common combustible gases1 together with the theoretical amount of air required for their combustion4 ,,table #cg ,,weight ,,and ,,calorific ,,value ,,of ,,various ,,gases ,,at #cb ,,degrees ,,fahrenheit ,,and ,,atmospheric ,,pressure ,,with ,,theoretical ,,amount ,,of ,,air ,,required ,,for ,,combustion ---------------------------------------- ----------------------- ,gas ,symbol ,cubic ,b4t4u,b4t4u4,cubic ,feet,cubic ,feet ,feet per per of ,air of ,air of ,gas,pound,cubic ,required ,required per ,foot per ,pound ,per ,cubic ,pound of ,gas ,foot of ,gas ---------------------------------------- ----------------------- ,hydrogen ,h #agg4ijfbjjj #cdi #dbh4be #b4da ,carbon ,monoxide ,,co #ab4ha #ddej #cdg #cj4fj #b4ci ,methane ,,ch#d #bb4cgbceej #ajec #bad4jj #i4eg ,acetylene ,c#b;,h#b #ac4gibadfe #aeef #afd4hg #aa4ic ,olefiant ,gas ,c#b;,h#d #ab4hjbaddj #afge #ahc4fj #ad4cc ,ethane ,c#b;,h#f #aa4idbbbcj #ahfb #aii4hh #af4gd ---------------------------------------- ----------------------- ,in applying this table1 as gas analyses may be reported either by weight or volume1 there is given in ,table #cccf a method of changing from volumetric analysis to analysis by weight4 ,examples3 #ast4 ,assume a blast furnace gas1 the analysis of which in percentages by weight is1 oxygen #b4g1 carbon monoxide #ai4e1 carbon dioxide #ah4g1 nitrogen #ei4a4 ,here the only combustible gas is the carbon monoxide1 and the heat value will be1 #j4aie #ddej #hfg4ge ,b4 t4 u4 per pound4 ,the net volume of air required to burn one pound of this gas will be1 #j4aie #cj4f #e4ifg cubic feet4 #bnd4 ,assume a natural gas1 the analysis of which in percentages by volume is oxygen #j4dj1 carbon monoxide #j4ie1 carbon dioxide #j4cd1 olefiant gas 7,c#b;,h#d7 #j4ff1 ethane 7,c#b;,h#f7 #c4ee1 marsh gas 7,,ch#d7 #gb4ae and hydrogen #ba4ie4 ,all but the oxygen and the carbon dioxide are combustibles1 and the heat per cubic foot will be1 ,from ,,co #j4jjie #cdg #c4cj ,c#b;,h#d #j4jjff #afge #aa4je ,c#b;,h#f #j4jcee #ahfb #ff4aj ,,ch#d #j4gbae #ajej #geg4eh ,h #j4baie #cdi #gf4fa ------ ,b4 t4 u4 per cubic foot #iad4fd ,the net air required for combustion of one cubic foot of the gas will be1 ,,co #j4jjie #b4ci #j4jb ,c#b;,h#d #j4jjff #ad4cc #j4ji ,c#b;,h#f #j4jcee #af4gd #j4ei ,,ch#d #j4gbae #i4eg #f4ij ,h #j4baie #b4da #j4ec ---- ,total net air per cubic foot #h4ac ,proximate ,analysis--,the proximate analysis of a fuel gives its proportions by weight of fixed carbon1 volatile combustible matter1 moisture and ash4 ,a method of making such an analysis which has been found to give eminently satisfactory results is described below4 ,from the coal sample obtained on the boiler trial1 an average sample of approximately #dj grams is broken up and weighed4 ,a good means of reducing such a sample is passing it through an ordinary coffee mill4 ,this sample should be placed in a double-walled air bath1 which should be kept at an approximately constant temperature of #aje degrees centigrade1 the sample being weighed at intervals until a minimum is reached4 ,the percentage of moisture can be calculated from the loss in such a drying4 ,for the determination of the remainder of the analysis1 and the heating value of the fuel1 a portion of this dried sample should be thoroughly pulverized1 and if it is to be kept1 should be placed in an air-tight receptacle4 ,one gram of the pulverized sample should be weighed into a porcelain crucible equipped with a well fitting lid4 ,this crucible should be supported on a platinum triangle and heated for seven minutes over the full flame of a ,bunsen burner4 ,at the end of such time the sample should be placed in a desiccator containing calcium chloride1 and when cooled should be weighed4 ,from the loss the percentage of volatile combustible matter may be readily calculated4 ,the same sample from which the volatile matter has been driven should be used in the determination of the percentage of ash4 ,this percentage is obtained by burning the fixed carbon over a ,bunsen burner or in a muffle furnace4 ,the burning should be kept up until a constant weight is secured1 and it may be assisted by stirring with a platinum rod4 ,the weight of the residue determines the percentage of ash1 and the percentage of fixed carbon is easily calculated from the loss during the determination of ash after the volatile matter has been driven off4 ,proximate analyses may be made and reported on a moist or dry basis4 ,the dry basis is that ordinarily accepted1 and this is the basis adopted throughout this book4 ,the method of converting from a moist to a dry basis is the same as described in the case of an ultimate analysis4 ,a proximate analysis is easily made1 gives information as to the general characteristics of a fuel and of its relative heating value4 ,table #ch gives the proximate analysis and calorific value of a number of representative coals found in the ,united ,states4 ,,table #ch ,,approximate ,,composition ,,and ,,calorific ,,value ,,of ,,certain ,,typical ,,american ,,coals ,no4 ,state ,county ,field1 ,bed ,mine ,size or ,vein ,,anthracites #a ,pa4 ,carbon ,lehigh ,beaver ,meadow #b ,pa4 ,dauphin ,schuylkill ,buckwheat #c ,pa4 ,lackawanna ,wyoming ,belleview ,no4 #b ,buck4 #d ,pa4 ,lackawanna ,wyoming ,johnson ,culm4 #e ,pa4 ,luzerne ,wyoming ,pittston ,no4 #b ,buck4 #f ,pa4 ,luzerne ,wyoming ,mammoth ,large #g ,pa4 ,luzerne ,wyoming ,exeter ,rice #h ,pa4 ,northumberland ,schuylkill ,treverton #i ,pa4 ,schuylkill ,schuylkill ,buck ,mountain #aj ,pa4 ,schuylkill ,york ,farm ,buckwheat #aa ,pa4 ,victoria ,buckwheat #ab ,pa4 ,carbon ,lehigh ,lehigh ,buck4 ,pea ,wilkes ,c4 ,co4 #ac ,pa4 ,carbon ,lehigh ,buckwheat #ad ,pa4 ,lackawanna ,del4 ,hud4 ,co4 ,no4 #a ,buck4 ,,semi-,,anthracites #ae ,pa4 ,lycoming ,loyalsock #af ,pa4 ,sullivan ,lopez #ag ,pa4 ,sullivan ,bernice ,,semi-,,bituminous #ah ,md4 ,alleghany ,big ,vein1 ,george's ,crk4 #ai ,md4 ,alleghany ,george's ,creek #bj ,md4 ,alleghany ,george's ,creek #ba ,md4 ,alleghany ,george's ,creek ,ocean ,no4 #g ,mine run #bb ,md4 ,alleghany ,cumberland #bc ,md4 ,garrett ,washington ,mine run ,no4 #c #bd ,pa4 ,bradford ,long ,valley #be ,pa4 ,tioga ,antrim #bf ,pa4 ,cambria ,b or ,miller ,soriman ,shaft ,c4 ,co4 #bg ,pa4 ,cambria ,b or ,miller ,henrietta #bh ,pa4 ,cambria ,b or ,miller ,penker #bi ,pa4 ,cambria ,b or ,miller ,lancashire #cj ,pa4 ,cambria ,lower ,penn4 ,c4 ,c4 ,mine run ,kittanning ,co4 ,no4 #c #ca ,pa4 ,cambria ,upper ,valley ,mine run ,kittanning #cb ,pa4 ,clearfield ,lower ,eureka ,mine run ,kittanning #cc ,pa4 ,clearfield ,ghem ,mine run #cd ,pa4 ,clearfield ,osceola #ce ,pa4 ,clearfield ,reynoldsville #cf ,pa4 ,clearfield ,atlantic- ,mine run ,clearfield #cg ,pa4 ,huntington ,barnet ,fulton ,carbon ,mine run #ch ,pa4 ,huntington ,rock ,hill ,mine run #ci ,pa4 ,somerset ,lower ,kimmelton ,mine run ,kittanning #dj ,pa4 ,somerset ,c ,prime ,vein ,jenner ,mine run ,proximate ,analysis 7,dry ,coal7 ,b4 t4 u4 ,no4 ,per ,pound ,authority ,moisture ,volatile ,fixed ,ash ,dry ,matter ,carbon ,coal #a #a4ej #b4da #ij4cj #g4bi ,gale #b #b4ae #ab4hh #gh4bc #h4hi #acacg ,whitham #c #h4bi #g4ha #gg4ai #ae4jj #abcda ,sadtler #d #ac4ij #aa4af #fe4if #bb4hh #ajeia ,b4 ,w4 ,co4 #e #c4ff #d4dj #gh4if #af4fd #abhfe ,b4 ,w4 ,co4 #f #d4jj #c4dd #ij4ei #e4ig #acgbj ,carpenter #g #j4be #h4ah #gi4fa #ab4ba #abdjj ,b4 ,w4 ,co4 #h #j4hd #f4gc #hf4ci #f4hh ,isherwood #i #c4ag #ib4da #d4db #adbbj ,carpenter #aj #j4ha #e4ea #ge4ij #ah4ei #aadcj #aa #d4cj #j4ee #hf4gc #ab4gb #abfdb ,b4 ,w4 ,co4 #ab #a4eg #f4bg #ff4ec #bg4bj #abhdh ,b4 ,w4 ,co4 #ac #e4jj #ha4jj #ad4jj #aahjj ,carpenter #ad #f4bj #aa4fj #abajj ,denton #ae #a4cj #h4gb #hd4dd #f4hd #af #e4dh #g4ec #ha4jj #aa4dg #acedg ,b4 ,w4 ,co4 #ag #a4bi #h4ba #hd4dc #g4cf #ah #c4ej #ba4cc #gb4dg #f4bj #adfhb ,b4 ,w4 ,co4 #ai #c4fc #af4bg #gf4ic #f4hj #adfie ,b4 ,w4 ,co4 #bj #b4bh #ai4dc #gg4dd #f4ac #adgic ,b4 ,w4 ,co4 #ba #a4ac #addea ,b4 ,w4 ,co4 #bb #a4ej #ag4bf #gf4fe #f4ji #adgjj #bc #b4cc #ad4ch #gd4ic #aj4di #adjcc ,u4 ,s4 ,geo4 ,s4 #cg #bd #a4ee #bj4cc #fh4ch #aa4bi #abife #be #b4ai #ah4dc #ga4hg #i4gj #acejj #bf #c4dj #bj4gj #ga4hd #g4df #addhd ,n4 ,y4 ,ed4 ,co4 #bg #a4bc #ah4cg #ge4bh #f4de #adggj ,so4 ,eng4 ,co4 #bh #c4fd #ba4cd #gj4dh #h4ah #addja ,b4 ,w4 ,co4 #bi #d4ch #ba4bj #gj4bg #h4ec #addec ,b4 ,w4 ,co4 #cj #c4ea #ag4dc #ge4fi #f4hh #adbgi ,u4 ,s4 ,geo4 ,s4 #ca #c4dj #ad4hi #ge4jc #aj4jh #adaeb ,b4 ,w4 ,co4 #cb #e4ij #af4ga #gg4bb #f4jg #adhdc ,u4 ,s4 ,geo4 ,s4 #cc #c4dc #ag4ec #fi4fg #ab4hj #acgdd ,b4 ,w4 ,co4 #cd #a4bd #be4dc #fh4ef #f4ja #acehi ,b4 ,w4 ,co4 #ce #b4ia #ba4ee #fi4jc #i4db #adfhe ,b4 ,w4 ,co4 #cf #a4ee #bc4cf #ga4ae #e4id #acifc ,whitham #cg #d4ej #ah4cd #gc4jf #h4fj #acggj ,b4 ,w4 ,co4 #ch #e4ia #ag4eh #gc4dd #h4ii #adaje ,b4 ,w4 ,co4 #ci #c4ji #ag4hd #gj4dg #aa4fi #acdbd ,u4 ,s4 ,geo4 ,s4 #dj #i4cg #af4dg #ge4gf #g4gg #adejg ,p4 ,r4 ,r4 ,,approximate ,,composition ,,and ,,calorific ,,value ,,of ,,certain ,,typical ,,american ,,coals--,continued ,no4 ,state ,county ,field1 ,bed ,mine ,size or ,vein #da ,w4 ,va4 ,fayette ,new ,river ,rush ,run ,mine run #db ,w4 ,va4 ,fayette ,new ,river ,loup ,creek #dc ,w4 ,va4 ,fayette ,new ,river ,slack #dd ,w4 ,va4 ,fayette ,new ,river ,mine run #de ,w4 ,va4 ,fayette ,new ,river ,rush ,run ,mine run #df ,w4 ,va4 ,mc,dowell ,pocahontas ,zenith ,mine run ,no4 #c #dg ,w4 ,va4 ,mc,dowell ,tug ,river ,big ,sandy ,mine run #dh ,w4 ,va4 ,mercer ,pocahontas ,mora ,lump #di ,w4 ,va4 ,mineral ,elk ,garden #ej ,w4 ,va4 ,mc,dowell ,pocahontas ,flat ,top ,mine run #ea ,w4 ,va4 ,mc,dowell ,pocahontas ,flat ,top ,slack #eb ,w4 ,va4 ,mc,dowell ,pocahontas ,flat ,top ,lump ,,bituminous #ec ,ala4 ,bibb ,cahaba ,hill ,creek ,mine run #ed ,ala4 ,jefferson ,pratt ,pratt ,no4 #ac #ee ,ala4 ,jefferson ,pratt ,warner ,mine run #ef ,ala4 ,jefferson ,coalburg ,mine run #eg ,ala4 ,walker ,horse ,creek ,ivy ,c4 ,i4 ,nut ,co4 ,no4 #h #eh ,ala4 ,walker ,jagger ,galloway ,c4 ,mine run ,co4 ,no4 #e #ei ,ark4 ,franklin ,denning ,western ,no4 #d ,nut #fj ,ark4 ,sebastian ,jenny ,lind ,mine ,no4 #ab ,lump #fa ,ark4 ,sebastian ,huntington ,cherokee ,mine run #fb ,col4 ,boulder ,south ,platte ,lafayette ,mine run #fc ,col4 ,boulder ,laramie ,simson ,mine run #fd ,col4 ,fremont ,canon ,city ,chandler ,nut and ,slack #fe ,col4 ,las ,animas ,trinidad ,hastings ,nut #ff ,col4 ,las ,animas ,trinidad ,moreley ,slack #fg ,col4 ,routt ,yampa ,oak ,creek #fh ,ill4 ,christian ,pana ,penwell ,col4 ,lump #fi ,ill4 ,franklin ,no4 #f ,benton ,egg #gj ,ill4 ,franklin ,big ,muddy ,zeigler inch #ga ,ill4 ,jackson ,big ,muddy #gb ,ill4 ,la ,salle ,streator #gc ,ill4 ,la ,salle ,streator ,marseilles ,mine run #gd ,ill4 ,macoupin ,nilwood ,mine ,no4 #b ,screenings #ge ,ill4 ,macoupin ,mt4 ,olive ,mine ,no4 #b ,mine run #gf ,ill4 ,madison ,belleville ,donk ,bros4 ,lump #gg ,ill4 ,madison ,glen ,carbon ,mine run #gh ,ill4 ,marion ,odin ,lump #gi ,ill4 ,mercer ,gilchrist ,screenings #hj ,ill4 ,montgomery ,pana or ,no4 #e ,coffeen ,mine run #ha ,ill4 ,peoria ,no4 #e ,empire #hb ,ill4 ,perry ,du ,quoin ,number #a ,screenings ,,approximate ,,composition ,,and ,,calorific ,,value ,,of ,,certain ,,typical ,,american ,,coals--,continued ,proximate ,analysis 7,dry ,coal7 ,b4 t4 u4 ,no4 ,per ,pound ,authority ,moisture ,volatile ,fixed ,ash ,dry ,matter ,carbon ,coal #da #b4ad #bb4hg #ga4ef #e4eg #adiei ,u4 ,s4 ,geo4 ,s4 #db #j4ee #ai4cf #gh4dh #b4af #adige ,hill #dc #f4ff #bj4id #gc4af #e4ij #addab ,b4 ,w4 ,co4 #dd #b4af #ag4hb #ge4ff #f4eb #adghf ,b4 ,w4 ,co4 #de #j4id #bb4af #ge4he #a4ii #aejjg ,b4 ,w4 ,co4 #df #d4he #ag4ad #gf4ed #f4cb #addhj ,u4 ,s4 ,geo4 ,s4 #dg #a4eh #ah4ee #gf4dd #d4ia #aeagj ,u4 ,s4 ,geo4 ,s4 #dh #a4gd #ah4ee #ge4ae #f4cj #aejae ,u4 ,s4 ,geo4 ,s4 #di #b4aj #ae4gj #ge4dj #h4ij #adaie ,b4 ,w4 ,co4 #ej #j4eb #bd4jb #gd4ei #a4ci #addij ,b4 ,w4 ,co4 #ea #c4bd #ae4cc #gg4fj #g4jg #adfec ,b4 ,w4 ,co4 #eb #c4fc #af4jc #gh4jd #e4ic #adief ,b4 ,w4 ,co4 #ec #f4ai #bh4eh #ee4fj #ae4hb #abegf ,b4 ,w4 ,co4 #ed #d4bi #be4gh #fg4fh #f4ed #addhb ,b4 ,w4 ,co4 #ee #b4ea #bg4hj #fa4ej #aj4gj #acfbh ,u4 ,s4 ,geo4 ,s4 #ef #j4id #ca4cd #fe4fe #c4ja #adeac ,b4 ,w4 ,co4 #eg #b4ef #ca4hb #ec4hi #ad4bi #abicg ,u4 ,s4 ,geo4 ,s4 #eh #d4hc #cd4fe #ea4ab #ad4jc #abigf ,u4 ,s4 ,geo4 ,s4 #ei #b4bb #ab4hc #ge4ce #aa4hb ,u4 ,s4 ,geo4 ,s4 #fj #a4jg #ag4jd #gd4de #h4ea #adbeb ,u4 ,s4 ,geo4 ,s4 #fa #j4ig #ai4hg #gj4cj #i4hc #adaei ,u4 ,s4 ,geo4 ,s4 #fb #ai4dh #ch4hj #di4jj #ab4bj #aaici ,b4 ,w4 ,co4 #fc #ai4gh #dd4fi #dh4fb #f4fi #abegg ,u4 ,s4 ,geo4 ,s4 #fd #i4cg #ch4aj #ea4ge #aj4ae #aahej ,b4 ,w4 ,co4 #fe #b4ae #ca4jg #ec4dj #ae4ec #abedg ,b4 ,w4 ,co4 #ff #a4hh #bh4dg #ee4eh #ae4ie #abgjc ,b4 ,w4 ,co4 #fg #f4fg #db4ia #ee4fd #a4de ,hill #fh #h4je #dc4fg #di4ig #f4cf #ajijj ,jones #fi #h4ca #cd4eb #ed4je #aa4dc #aagbg ,u4 ,s4 ,geo4 ,s4 #gj #ac4bh #ca4ig #eg4cg #aj4ff #abheg ,u4 ,s4 ,geo4 ,s4 #ga #d4he #ca4ee #fb4ai #f4bf #aadff ,breckenridge #gb #h4dj #da4gf #ea4db #f4hb #aagbg ,breckenridge #gc #ab4ih #dc4gc #di4ac #g4ad #ajhii ,b4 ,w4 ,co4 #gd #ac4cd #cd4ge #dd4ee #bj4gj #ajgha ,b4 ,w4 ,co4 #ge #ac4ed #da4bh #df4cj #ab4db #ajhjg ,u4 ,s4 ,geo4 ,s4 #gf #ac4dg #ch4fi #dh4jg #ac4bd #abdbg ,u4 ,s4 ,geo4 ,s4 #gg #i4gh #ch4ah #ea4eb #aj4cj #aafgb ,bryan #gh #f4bj #db4ia #di4jf #h4jc #aahhj ,breckenridge #gi #h4ej #cf4ag #da4fd #bb4ai #ajdig ,breckenridge #hj #aa4ic #cd4je #di4he #af4aj #ajcjc ,u4 ,s4 ,geo4 ,s4 #ha #ag4fd #ca4ia #df4ag #ba4ib #ajgje ,b4 ,w4 ,co4 #hb #i4ha #cc4fg #dh4cf #ag4ig #aabbi ,b4 ,w4 ,co4 ,,approximate ,,composition ,,and ,,calorific ,,value ,,of ,,certain ,,typical ,,american ,,coals--,continued ,no4 ,state ,county ,field1 ,bed ,mine ,size or ,vein #hc ,ill4 ,perry ,du ,quoin ,willis ,mine run #hd ,ill4 ,sangamon ,pawnee ,slack #he ,ill4 ,st4 ,clair ,standard ,nigger ,hollow ,mine run #hf ,ill4 ,st4 ,clair ,standard ,maryville ,mine run #hg ,ill4 ,williamson ,big ,muddy ,daws ,mine run #hh ,ill4 ,williamson ,carterville ,carterville or ,no4 #g #hi ,ill4 ,williamson ,carterville ,burr ,nut1 ,pea or ,no4 #g and ,slack #ij ,ind4 ,brazil ,brazil ,gartside ,block #ia ,ind4 ,clay ,louise ,block #ib ,ind4 ,green ,island ,city ,mine run #ic ,ind4 ,knox ,vein ,no4 #e ,tecumseh ,mine run #id ,ind4 ,parke ,vein ,no4 #f ,parke ,coal ,co4 ,lump #ie ,ind4 ,sullivan ,sullivan ,no4 #f ,mildred ,washed #if ,ind4 ,vigo ,number #f ,fontanet ,mine run #ig ,ind4 ,vigo ,number #g ,red ,bird ,mine run #ih ,iowa ,appanoose ,mystic ,mine ,no4 #c ,lump #ii ,iowa ,lucas ,lucas ,inland ,no4 #a ,mine run #ajj ,iowa ,marion ,big ,vein ,liberty ,no4 #e ,mine run #aja ,iowa ,polk ,third ,seam ,altoona ,no4 #d ,lump #ajb ,iowa ,wapello ,wapello ,lump #ajc ,kan4 ,cherokee ,weir ,pittsburgh ,southwestern ,lump ,dev4 ,co4 #ajd ,kan4 ,cherokee ,cherokee ,screenings #aje ,kan4 ,cherokee ,cherokee ,lump #ajf ,kan4 ,linn ,boicourt ,lump #ajg ,ky4 ,bell ,straight ,creek ,str4 ,ck4 ,c4 ,mine run ,c4 ,co4 #ajh ,ky4 ,hopkins ,bed ,no4 #i ,earlington ,lump #aji ,ky4 ,hopkins ,bed ,no4 #i ,barnsley ,mine run #aaj ,ky4 ,hopkins ,vein ,no4 #ad ,nebo ,pea and ,slack #aaa ,ky4 ,johnson ,vein ,no4 #a ,miller's ,creek ,mine run #aab ,ky4 ,mulenburg ,bed ,no4 #i ,pierce ,pea and ,slack #aac ,ky4 ,pulaski ,greensburg #aad ,ky4 ,webster ,bed ,no4 #i ,pea and ,slack #aae ,ky4 ,whitley ,jellico ,nut and ,slack #aaf ,mo4 ,adair ,danforth ,mine run #aag ,mo4 ,bates ,rich ,hill ,new ,home ,mine run #aah ,mo4 ,clay ,lexington ,mo4 ,city ,coal ,co4 #aai ,mo4 ,lafayette ,waverly ,buckthorn #abj ,mo4 ,lafayette ,waverly ,higbee #aba ,mo4 ,linn ,bevier ,marceline #abb ,mo4 ,macon ,bevier ,northwest ,coal ,co4 #abc ,mo4 ,morgan ,morgan ,co4 ,morgan ,co4 ,mine run ,coal ,co4 #abd ,mo4 ,putnam ,mendotta ,mendotta ,no4 #h #abe ,n4,mex4 ,mc,kinley ,gallup ,gibson ,pea and ,slack ,proximate ,analysis 7,dry ,coal7 ,b4 t4 u4 ,no4 ,per ,pound ,authority ,moisture ,volatile ,fixed ,ash ,dry ,matter ,carbon ,coal #hc #g4bb #cc4jf #ec4ig #ab4ig #aaceb ,u4 ,s4 ,geo4 ,s4 #hd #d4ha #da4ec #ci4fb #ah4he #ajbbj ,jones #he #ad4ci #cb4ij #dd4hd #bb4bf #aajei ,b4 ,w4 ,co4 #hf #ae4ga #ch4aj #da4aj #bj4hj #ajiii ,b4 ,w4 ,co4 #hg #h4ag #cd4cc #eb4ej #ac4ag #abfdc ,u4 ,s4 ,geo4 ,s4 #hh #d4ff #ce4fe #ef4hf #g4di #abbhf ,univ4 of ,ill4 #hi #aa4ia #cc4gj #ee4ij #aj4dj #abicb ,b4 ,w4 ,co4 #ij #b4hc #dj4jc #ea4ig #h4jj #accge ,stillman #ia #j4hc #ci4gj #eb4bh #h4jb #acbdh ,jones #ib #f4ag #ce4db #ec4ee #aa4jc #aaiaf ,dearborn #ic #aj4gc #ce4ge #ed4df #i4gi #abiaa ,b4 ,w4 ,co4 #id #aj4gb #dd4jb #df4cc #i4fe #aagfg ,u4 ,s4 ,geo4 ,s4 #ie #af4ei #db4ag #dh4dd #i4ei #accgg ,u4 ,s4 ,geo4 ,s4 #if #b4bh #cd4ie #ej4ej #ad4ee #aaibj ,dearborn #ig #aa4fb #da4ag #df4gf #ab4jg #abgdj ,u4 ,s4 ,geo4 ,s4 #ih #ac4dh #ci4dj #dc4ji #ag4ea #aafgh ,u4 ,s4 ,geo4 ,s4 #ii #af4ja #cg4hb #df4bd #ae4id #aaifc ,u4 ,s4 ,geo4 ,s4 #ajj #ad4hh #da4ec #ci4fc #ah4hd #aaddc ,u4 ,s4 ,geo4 ,s4 #aja #ab4dd #da4bg #dj4hf #ag4hg #aafga ,u4 ,s4 ,geo4 ,s4 #ajb #h4fi #cf4bc #dc4fh #bj4ji #aaddc ,u4 ,s4 ,geo4 ,s4 #ajc #d4ca #cc4hh #ec4fg #ab4de #acadd ,u4 ,s4 ,geo4 ,s4 #ajd #f4af #ce4ef #df4ij #ag4ed #ajage ,jones #aje #a4ha #cd4gg #eb4gg #ab4df #abeeg ,jones #ajf #d4gd #cf4ei #dg4jg #af4cd #ajcib ,jones #ajg #b4hi #cf4fg #eg4bd #f4ji #adcfb ,u4 ,s4 ,geo4 ,s4 #ajh #f4hi #dj4cj #ee4af #d4ed #accha ,st4 ,col4 ,ky4 #aji #g4ib #dj4ec #dh4gj #aj4gg #acjcf ,u4 ,s4 ,geo4 ,s4 #aaj #h4jb #ca4ia #ed4jb #ad4jg #abddh ,b4 ,w4 ,co4 #aaa #e4ab #ch4df #eh4fc #b4ia #acgdc ,u4 ,s4 ,geo4 ,s4 #aab #i4bb #cc4id #eb4ah #ac4hh #abbbi ,b4 ,w4 ,co4 #aac #b4hj #bf4ed #fc4eh #i4hh #adjie ,n4 ,y4 ,ed4 ,co4 #aad #g4cj #ca4jh #fj4gb #h4bj #acfjj ,b4 ,w4 ,co4 #aae #c4hb #ca4hb #eh4gh #i4dj #acage ,b4 ,w4 ,co4 #aaf #i4jj #cj4ee #df4bf #bc4ai #ihhi ,b4 ,w4 ,co4 #aag #g4bh #cg4fb #dc4hc #ah4ee #abaji ,u4 ,s4 ,geo4 ,s4 #aah #ab4de #ci4ci #dh4dg #ab4ad #abhge ,univ4 of ,mo4 #aai #h4eh #da4gh #de4ii #ab4bc #abgce ,univ4 of ,mo4 #abj #aj4hd #ca4gb #ee4bi #ab4ii #abejj ,univ4 of ,mo4 #aba #i4de #cf4gb #eb4bj #aa4jh #acahj ,univ4 of ,mo4 #abb #ac4ji #cg4hc #db4ie #ai4bb #aaejj ,u4 ,s4 ,geo4 ,s4 #abc #ab4bd #de4fi #dg4ih #f4cc #adaig ,u4 ,s4 ,geo4 ,s4 #abd #bj4gh #ci4cf #ej4jj #aj4fd #abfjb ,u4 ,s4 ,geo4 ,s4 #abe #ab4ag #cf4ca #ea4ag #ab4eb #ababf ,b4 ,w4 ,co4 ,,approximate ,,composition ,,and ,,calorific ,,value ,,of ,,certain ,,typical ,,american ,,coals--,continued ,no4 ,state ,county ,field1 ,bed ,mine ,size or ,vein #abf ,ohio ,athens ,hocking ,valley ,sunday ,creek ,slack #abg ,ohio ,belmont ,pittsburgh ,neff ,coal ,co4 ,mine run ,no4 #h #abh ,ohio ,columbiana ,middle ,palestine ,kittanning #abi ,ohio ,coshocton ,middle ,morgan ,run ,mine run ,kittanning #acj ,ohio ,guernsey ,vein ,no4 #g ,little ,kate #aca ,ohio ,hocking ,hocking ,valley ,lump #acb ,ohio ,hocking ,hocking ,valley #acc ,ohio ,jackson ,brookville ,superior ,mine run ,coal ,co4 #acd ,ohio ,jackson ,lower ,superior ,mine run ,kittanning ,coal ,co4 #ace ,ohio ,jackson ,quakertown ,wellston #acf ,ohio ,jefferson ,pittsburgh ,crow ,hollow inch or ,no4 #h #acg ,ohio ,jefferson ,pittsburgh ,rush ,run ,no4 #a inch or ,no4 #h #ach ,ohio ,perry ,hocking ,congo #aci ,ohio ,stark ,massillon ,slack #adj ,ohio ,vinton ,brookville ,clarion ,nut and or ,no4 #d ,slack #ada ,okla4 ,choctaw ,mc,alester ,edwards ,no4 #a ,mine run #adb ,okla4 ,choctaw ,mc,alester ,adamson ,slack #adc ,okla4 ,creek ,henrietta ,lump and ,slack #add ,pa4 ,allegheny ,pittsburgh ,slack #crd ,pool #ade ,pa4 ,allegheny ,monongahela ,turtle ,creek #adf ,pa4 ,allegheny ,pittsburgh ,bertha inch #adg ,pa4 ,cambria ,beach ,creek ,slack #adh ,pa4 ,cambria ,miller ,lincoln ,mine run #adi ,pa4 ,clarion ,lower ,freeport #aej ,pa4 ,fayette ,connellsville ,slack #aea ,pa4 ,greene ,youghiogheny ,lump #aeb ,pa4 ,greene ,westmoreland ,screenings #aec ,pa4 ,indiana ,iselin ,mine run #aed ,pa4 ,jefferson ,punxsutawney ,mine run #aee ,pa4 ,lawrence ,middle ,kittanning #aef ,pa4 ,mercer ,taylor #aeg ,pa4 ,washington ,pittsburgh ,ellsworth #aeh ,pa4 ,washington ,youghiogheny ,anderson inch #aei ,pa4 ,westmoreland ,pittsburgh ,scott ,haven ,lump #afj ,tenn4 ,campbell ,jellico #afa ,tenn4 ,claiborne ,mingo #afb ,tenn4 ,marion ,etna #afc ,tenn4 ,morgan ,brushy ,mt4 #afd ,tenn4 ,scott ,glen ,mary ,no4 #d ,glen ,mary #afe ,tex4 ,maverick ,eagle ,pass #aff ,tex4 ,paolo ,pinto ,thurber ,mine run #afg ,tex4 ,paolo ,pinto ,strawn ,mine run #afh ,va4 ,henrico ,gayton ,proximate ,analysis 7,dry ,coal7 ,b4 t4 u4 ,no4 ,per ,pound ,authority ,moisture ,volatile ,fixed ,ash ,dry ,matter ,carbon ,coal #abf #ab4af #cd4fd #ec4aj #ab4bf #abbad #abg #e4ca #ch4gh #eb4bb #i4jj #abhdc ,u4 ,s4 ,geo4 ,s4 #abh #b4ae #cg4eg #ea4hj #aj4fc #accgj ,lord ,haas #abi #da4gf #de4bd #ac4jj #acbci ,b4 ,w4 ,co4 #acj #f4ai #cc4jb #ei4if #g4jb #acfcd ,b4 ,w4 ,co4 #aca #f4de #ci4ab #ej4jh #aj4hj #abgjj ,lord ,haas #acb #b4fj #dj4hj #dg4fj #aa4fj #abage ,jones #acc #g4ei #ch4de #dc4ii #ag4ef #aagjd ,u4 ,s4 ,geo4 ,s4 #acd #h4ii #da4dc #ej4jf #h4ea #acaac ,u4 ,s4 ,geo4 ,s4 #ace #c4ch #ce4bf #ed4ah #g4ef #abejf ,hill #acf #d4jd #dj4jh #eb4bg #i4fe #accgd ,u4 ,s4 ,geo4 ,s4 #acg #d4gd #cf4jh #ed4ha #i4aa #acecb ,u4 ,s4 ,geo4 ,s4 #ach #f #da #ch4cc #df4ga #ad4if #abbhd ,b4 ,w4 ,co4 #aci #f4fg #dj4jb #df4df #ac4eb #aahfj ,b4 ,w4 ,co4 #adj #b4dg #db4ch #ej4ci #f4bc #acdba ,u4 ,s4 ,geo4 ,s4 #ada #d4gi #ci4ah #di4ig #aj4he #acjje ,u4 ,s4 ,geo4 ,s4 #adb #d4gb #bh4ed #eh4ag #ac4bi #abaje ,b4 ,w4 ,co4 #adc #g4fe #cf4gg #ej4ad #ac4ji #abhcd ,u4 ,s4 ,geo4 ,s4 #add #a4gg #cb4jf #eg4aa #aj4hc #acbje ,carpenter #ade #a4ge #cf4he #ec4id #i4ba #acdhj ,lord ,haas #adf #b4fa #ce4hf #eg4ha #f4cc #aciig ,u4 ,s4 ,geo4 ,s4 #adg #c4ja #cb4hg #ee4hf #aa4bg #acgee ,b4 ,w4 ,co4 #adh #e4ci #cj4hc #fa4je #h4ab #acfjj ,b4 ,w4 ,co4 #adi #j4ed #ce4ic #eg4ff #f4da #acedg #aej #a4he #bh4gc #fc4bb #g4ie #acgge ,whitham #aea #a4be #cb4fj #ed4gj #ab4gj #acajj ,b4 ,w4 ,co4 #aeb #aa4ab #ca4fg #ee4fa #ab4gb #acajj ,p4 ,r4 ,r4 #aec #b4gj #bi4cc #fc4ef #g4aa #adbbj ,b4 ,w4 ,co4 #aed #c4ch #bi4cc #fd4ic #e4gc #adgha ,b4 ,w4 ,co4 #aee #j4gj #cg4jf #ef4bd #f4gj #achdj ,lord ,haas #aef #d4ah #cb4ai #ee4ee #ab4bf #abhbj ,b4 ,w4 ,co4 #aeg #b4df #ce4ce #eh4df #f4ai #adjac ,u4 ,s4 ,geo4 ,s4 #aeh #a4jj #ci4bi #ed4hj #e4ia #acgbi ,jones #aei #d4jf #cb4ia #ei4gh #g4ca #acicd ,b4 ,w4 ,co4 #afj #a4hj #cg4gf #fb4ab #a4ab #achdf ,u4 ,s4 ,navy #afa #d4dj #cd4ca #ei4bb #f4dg ,u4 ,s4 ,geo4 ,s4 #afb #c4af #cb4ih #ef4ei #aj4dc #afc #a4gg #cc4df #ed4gc #aa4hg #achbd ,b4 ,w4 ,co4 #afd #a4ec #dj4hj #ef4gh #b4db #adfbe ,ky4 ,state ,col4 #afe #e4db #cc4gc #dd4hi #ba4ch #ajide ,b4 ,w4 ,co4 #aff #a4ij #cf4ja #di4ji #ad4ij #abgfj ,b4 ,w4 ,co4 #afg #d4ai #ce4dj #eb4ih #aa4fb #acbjb ,b4 ,w4 ,co4 #afh #j4hb #ag4ad #gd4ib #g4id #adcfc ,b4 ,w4 ,co4 ,,approximate ,,composition ,,and ,,calorific ,,value ,,of ,,certain ,,typical ,,american ,,coals--,continued ,no4 ,state ,county ,field1 ,bed ,mine ,size or ,vein #afi ,va4 ,lee ,darby ,darby #a inch #agj ,va4 ,lee ,mc,connel ,wilson ,mine run #aga ,va4 ,wise ,upper ,banner ,coburn #c inch #agb ,va4 ,rockingham ,clover ,hill #agc ,va4 ,russel ,clinchfield #agd ,va4 ,monongahela ,bernmont #age ,w4 ,va4 ,harrison ,pittsburgh ,ocean ,mine run #agf ,w4 ,va4 ,harrison ,girard ,nut1 ,pea and ,slack #agg ,w4 ,va4 ,kanawha ,winifrede ,winifrede #agh ,w4 ,va4 ,kanawha ,keystone ,keystone ,mine run #agi ,w4 ,va4 ,logan ,island ,creek ,nut and ,slack #ahj ,w4 ,va4 ,marion ,fairmont ,kingmont #aha ,w4 ,va4 ,mingo ,thacker ,maritime #ahb ,w4 ,va4 ,mingo ,glen ,alum ,glen ,alum ,mine run #ahc ,w4 ,va4 ,preston ,bakerstown #ahd ,w4 ,va4 ,putnam ,pittsburgh ,black ,betsy ,bug dust #ahe ,w4 ,va4 ,randolph ,upper ,freeport ,coalton ,lump and ,nut ,,lignites ,,and ,,lignitic ,,coals #ahf ,col4 ,boulder ,rex #ahg ,col4 ,el ,paso ,curtis #ahh ,col4 ,el ,paso ,pike ,view #ahi ,col4 ,gunnison ,south ,platte ,mt4 ,carbon #aij ,col4 ,las ,animas ,acme #aia ,col4 ,lehigh #aib ,n4 ,dak4 ,mc,lean ,eckland ,mine run #aic ,n4 ,dak4 ,mc,lean ,wilton ,lump #aid ,n4 ,dak4 ,mc,lean ,casino #aie ,n4 ,dak4 ,stark ,lehigh ,lehigh ,mine run #aif ,n4 ,dak4 ,william ,williston ,mine run #aig ,n4 ,dak4 ,william ,williston ,mine run #aih ,tex4 ,bastrop ,bastrop ,glenham #aii ,tex4 ,houston ,crockett #bjj ,tex4 ,houston ,houston ,c4 ,c4 ,co4 #bja ,tex4 ,milam ,rockdale ,worley #bjb ,tex4 ,robertson ,calvert ,coaling ,no4 #a #bjc ,tex4 ,wood ,hoyt ,consumer's ,lig4 ,co4 #bjd ,tex4 ,wood ,hoyt #bje ,wash4 ,king ,black ,diamond #bjf ,wyo4 ,carbon ,hanna ,mine run #bjg ,wyo4 ,crook ,black ,hills ,stilwell ,coal ,co4 #bjh ,wyo4 ,sheridan ,sheridan ,monarch #bji ,wyo4 ,sweetwater ,rock ,spring ,screenings #baj ,wyo4 ,uinta ,adaville ,lazeart ,proximate ,analysis 7,dry ,coal7 ,b4 t4 u4 ,no4 ,per ,pound ,authority ,moisture ,volatile ,fixed ,ash ,dry ,matter ,carbon ,coal #afi #d4ce #ch4df #ef4ia #d4fc #acici ,u4 ,s4 ,geo4 ,s4 #agj #c4ce #cf4ce #eg4hh #e4gg #acica ,u4 ,s4 ,geo4 ,s4 #aga #c4je #cb4fe #fb4gc #d4fb #addgj ,u4 ,s4 ,geo4 ,s4 #agb #ca4gg #eg4ih #aj4be #acajc #agc #b4jj #ce4gb #ef4ab #h4af #adbjj #agd #cb4jj #ei4ij #h4aj #acdbd ,carpenter #age #b4dg #ci4ce #eb4gh #g4hg #adbjb ,u4 ,s4 ,geo4 ,s4 #agf #cf4ff #eg4di #e4he #adedh ,b4 ,w4 ,co4 #agg #a4je #cb4gd #fd4ch #b4hh #adaaa ,hill #agh #b4ba #cc4bi #eh4fa #h4aj #adbjb ,u4 ,s4 ,geo4 ,s4 #agi #a4ab #ch4fa #ee4ia #e4dh #adbgc ,hill #ahj #a4ij #ce4ca #eg4cd #g4ce #adaih ,u4 ,s4 ,geo4 ,s4 #aha #j4fh #ca4hi #fc4dh #d4fc #adabf ,hill #ahb #c4jb #cc4ha #ei4de #f4gd #addad ,u4 ,s4 ,geo4 ,s4 #ahc #d4ad #bi4ji #fc4ej #g4da #adedf ,u4 ,s4 ,geo4 ,s4 #ahd #g4da #cb4hd #ec4if #ac4bj #abefh ,b4 ,w4 ,co4 #ahe #b4aa #bi4eg #ei4ic #aj4ej #ached ,u4 ,s4 ,geo4 ,s4 #ahf #af4je #db4ab #dg4ig #i4ia #ajfgh ,b4 ,w4 ,co4 #ahg #bc4be #db4aa #di4ch #h4ea #aajij ,b4 ,w4 ,co4 #ahh #bc4gg #dh4gj #da4dg #i4hc #ajfbi ,b4 ,w4 ,co4 #ahi #bj4ch #df4ch #dg4ej #f4ab #aij #af4gd #dg4ij #dd4fj #g4ej ,col4 ,sc4 of ,m4 #aia #ah4cj #de4bi #dd4fg #aj4jd #aib #bi4fe #de4ef #dg4je #g4ci #ajeec ,lord #aic #ce4if #di4hd #ch4je #ab4aa #aajcf ,u4 ,s4 ,geo4 ,s4 #aid #bi4fe #df4ef #ch4gj #ad4gd ,lord #aie #ce4hd #dc4hd #ci4ei #af4eg #ajaba ,u4 ,s4 ,geo4 ,s4 #aif #da4gf #ci4cg #dh4ji #ab4ed #ajaba ,b4 ,w4 ,co4 #aig #db4gd #dj4hc #dg4gi #aa4ch #ajbga ,b4 ,w4 ,co4 #aih #cb4gg #db4gf #cf4hh #bj4cf #hieh ,b4 ,w4 ,co4 #aii #bc4bg #dj4ie #ch4cg #bj4fh #ajhhf ,u4 ,s4 ,geo4 ,s4 #bjj #ca4dh #df4ic #cd4dj #ah4hg #ajagf ,b4 ,w4 ,co4 #bja #cb4dh #dc4jd #da4ad #ae4hb #ajjba ,b4 ,w4 ,co4 #bjb #cb4ja #dc4gj #dc4jh #ac4bb #ajgec ,b4 ,w4 ,co4 #bjc #cc4ih #df4ig #da4dj #aa4fc #ajfjj ,u4 ,s4 ,geo4 ,s4 #bjd #cj4be #dc4bg #da4df #ae4bg #ajeig #bje #c4ga #dh4gb #df4ef #d4gb ,gale #bjf #f4dd #ea4cb #dc4jj #e4fh #aafjg ,b4 ,w4 ,co4 #bjg #ai4jh #de4ba #df4db #h4cg #abfda ,u4 ,s4 ,geo4 ,s4 #bjh #ba4ah #ea4hg #dj4dc #g4gj #abcaf ,u4 ,s4 ,geo4 ,s4 #bji #g4gj #ch4eg #ef4ii #d4dd #abecd ,b4 ,w4 ,co4 #baj #ai4ae #de4ej #dh4aa #f4ci #ihfh ,u4 ,s4 ,geo4 ,s4 ,illustration3 ,portion of #ab1jhj ,horse-power ,installation of ,babcock ,wilcox ,boilers and ,superheaters at the ,potomac ,electric ,co41 ,washington1 ,d4 ,c4 ,,table #ci ,,showing ,,relation ,,between ,,proximate ,,and ,,ultimate ,,analyses ,,of ,,coal ,common in ,proximate ,proximate ,ultimate ,analysis ,ultimate ,analysis ,analysis ---------------------------------------- ---------------------------- ,v ,h ,n ,m o y i ,s o l ,m ,c ,c d ,o t u i ,s a a ,f a a r x r l s t t t i r r o y o p t a ,field i t x b b g g g h ,a u t or l e e o o e e e e s r e ,bed ,mine e r d n n n n n r h e ---------------------------------------- -------------------- ,icy ,coal ,iron ,horse ,co4 ,ala ,creek ,no4 #h #ca4haec4ijgb4jbd4gh #f4dea4ff 4#hjad4bi #b4ef ---------------------------------------- --------------------- ,central ,c4 ,c4 ,hunt- ,co4 ,arkington ,no4 #c #ah4iifg4gagf4cgc4ij #c4gaa4dia4bcac4cj #a4ii ---------------------------------------- -------------------- ,pana ,clover or ,leaf1 ,ill ,no4 #e ,no4 #a #cg4bbde4fdfc4jdd4diaj4jda4bhd4jaag4adac 4ai ---------------------------------------- -------------------- ,no4 #e1 ,warrick ,ind ,co4 ,electric#da4hedd4defh4jhd4gh #g4efa4ced4ecac4gj #i4aa ---------------------------------------- -------------------- ,no4 #aa1 ,st4 ,hopkins,bernard1 ,ky ,co4 ,no4 #aa #da4ajdi4fjgb4bbe4jf #h4dda4ccc4fe #i4cj #g4gf ---------------------------------------- -------------------- ,b or ,lower ,kittan- ,eureka1 ,pa ning ,no4 #ca #af4gagg4bbhd4ded4be #c4jda4bh 4#ia #f4jg 4#ef ---------------------------------------- -------------------- ,indiana ,pa ,co4 #bi4eefb4fdgi4hfe4jb #d4bga4hfa4ah #g4ha #b4ij ---------------------------------------- -------------------- ,w4 ,fire ,rush ,va ,creek ,run #bb4hgga4efhc4gad4fd #c4fga4gj 4#ga #e4eg #b4ad ,table #ci gives for comparison the ultimate and proximate analyses of certain of the coals with which tests were made in the coal testing plant of the ,united ,states ,geological ,survey at the ,louisiana ,purchase ,exposition at ,st4 ,louis4 ,the heating value of a fuel cannot be directly computed from a proximate analysis1 due to the fact that the volatile content varies widely in different fuels in composition and in heating value4 ,some methods have been advanced for estimating the calorific value of coals from the proximate analysis4 ,william ,kent#ch deducted from ,mahler's tests of ,european coals the approximate heating value dependent upon the content of fixed carbon in the combustible4 ,the relation as deduced by ,kent between the heat and value per pound of combustible and the per cent of fixed carbon referred to combustible is represented graphically by ,fig4 #bc4 ,goutal gives another method of determining the heat value from a proximate analysis1 in which the carbon is given a fixed value and the heating value of the volatile matter is considered as a function of its percentage referred to combustible4 ,goutal's method checks closely with ,kent's determinations4 ,all the formulae1 however1 for computing the calorific value of coals from a proximate analysis are ordinarily limited to certain classes of fuels4 ,mr4 ,kent1 for instance1 states that his deductions are correct within a close limit for fuels containing more than #fj per cent of fixed carbon in the combustible1 while for those containing a lower percentage1 the error may be as great as #d per cent1 either high or low4 ,while the use of such computations will serve where approximate results only are required1 that they are approximate should be thoroughly understood4 ,calorimetry--,an ultimate or a proximate analysis of a fuel is useful in determining its general characteristics1 and as described on page #ahc1 may be used in the calculation of the approximate heating value4 ,where the efficiency of a boiler is to be computed1 however1 this heating value should in all instances be determined accurately by means of a fuel calorimeter4 ,graph3 ,b4,t4,u4 per ,pound of ,combustible against ,per ,cent of ,fixed ,carbon in ,combustible ,fig4 #bc4 ,graphic ,representation of ,relation between ,heat ,value ,per ,pound of ,combustible and ,fixed ,carbon in ,combustible as ,deduced by ,wm4 ,kent4 ,in such an apparatus the fuel is completely burned and the heat generated by such combustion is absorbed by water1 the amount of heat being calculated from the elevation in the temperature of the water4 ,a calorimeter which has been accepted as the best for such work is one in which the fuel is burned in a steel bomb filled with compressed oxygen4 ,the function of the oxygen1 which is ordinarily under a pressure of about #be atmospheres1 is to cause the rapid and complete combustion of the fuel sample4 ,the fuel is ignited by means of an electric current1 allowance being made for the heat produced by such current1 and by the burning of the fuse wire4 ,a calorimeter of this type which will be found to give satisfactory results is that of ,m4 ,pierre ,mahler1 illustrated in ,fig4 #bd and consisting of the following parts3 ,a water jacket ,a1 which maintains constant conditions outside of the calorimeter proper1 and thus makes possible a more accurate computation of radiation losses4 ,the porcelain lined steel bomb ,b1 in which the combustion of the fuel takes place in compressed oxygen4 ,illustration3 ,fig4 #bd4 ,mahler ,bomb ,calorimeter ,the platinum pan ,c1 for holding the fuel4 ,the calorimeter proper ,d1 surrounding the bomb and containing a definite weighed amount of water4 ,an electrode ,e1 connecting with the fuse wire ,f1 for igniting the fuel placed in the pan ,c4 ,a support ,g1 for a water agitator4 ,a thermometer ,i1 for temperature determination of the water in the calorimeter4 ,the thermometer is best supported by a stand independent of the calorimeter1 so that it may not be moved by tremors in the parts of the calorimeter1 which would render the making of readings difficult4 ,to obtain accuracy of readings1 they should be made through a telescope or eyeglass4 ,a spring and screw device for revolving the agitator4 ,a lever ,l1 by the movement of which the agitator is revolved4 ,a pressure gauge ,m1 for noting the amount of oxygen admitted to the bomb4 ,between #bj and #be atmospheres are ordinarily employed4 ,an oxygen tank ,o4 ,a battery or batteries ,p1 the current from which heats the fuse wire used to ignite the fuel4 ,this or a similar calorimeter is used in the determination of the heat of combustion of solid or liquid fuels4 ,whatever the fuel to be tested1 too much importance cannot be given to the securing of an average sample4 ,where coal is to be tested1 tests should be made from a portion of the dried and pulverized laboratory sample1 the methods of obtaining which have been described4 ,in considering the methods of calorimeter determination1 the remarks applied to coal are equally applicable to any solid fuel1 and such changes in methods as are necessary for liquid fuels will be self-evident from the same description4 ,approximately one gram of the pulverized dried coal sample should be placed directly in the pan of the calorimeter4 ,there is some danger in the using of a pulverized sample from the fact that some of it may be blown out of the pan when oxygen is admitted4 ,this may be at least partially overcome by forming about two grams into a briquette by the use of a cylinder equipped with a plunger and a screw press4 ,such a briquette should be broken and approximately one gram used4 ,if a pulverized sample is used1 care should be taken to admit oxygen slowly to prevent blowing the coal out of the pan4 ,the weight of the sample is limited to approximately one gram since the calorimeter is proportioned for the combustion of about this weight when under an oxygen pressure of about #be atmospheres4 ,a piece of fine iron wire is connected to the lower end of the plunger to form a fuse for igniting the sample4 ,the weight of iron wire used is determined1 and if after combustion a portion has not been burned1 the weight of such portion is determined4 ,in placing the sample in the pan1 and in adjusting the fuse1 the top of the calorimeter is removed4 ,it is then replaced and carefully screwed into place on the bomb by means of a long handled wrench furnished for the purpose4 ,the bomb is then placed in the calorimeter1 which has been filled with a definite amount of water4 ,this weight is the water equivalent of the apparatus1 i4 e41 the weight of water1 the temperature of which would be increased one degree for an equivalent increase in the temperature of the combined apparatus4 ,it may be determined by calculation from the weights and specific heats of the various parts of the apparatus4 ,such a determination is liable to error1 however1 as the weight of the bomb lining can only be approximated1 and a considerable portion of the apparatus is not submerged4 ,another method of making such a determination is by the adding of definite weights of warm water to definite amounts of cooler water in the calorimeter and taking an average of a number of experiments4 ,the best method for the making of such a determination is probably the burning of a definite amount of resublimed naphthaline whose heat of combustion is known4 ,the temperature of the water in the water jacket of the calorimeter should be approximately that of the surrounding atmosphere4 ,the temperature of the weighed amount of water in the calorimeter is made by some experimenters slightly greater than that of the surrounding air in order that the initial correction for radiation will be in the same direction as the final correction4 ,other experimenters start from a temperature the same or slightly lower than the temperature of the room1 on the basis that the temperature after combustion will be slightly higher than the room temperature and the radiation correction be either a minimum or entirely eliminated4 ,while no experiments have been made to show conclusively which of these methods is the better1 the latter is generally used4 ,after the bomb has been placed in the calorimeter1 it is filled with oxygen from a tank until the pressure reaches from #bj to #be atmospheres4 ,the lower pressure will be sufficient in all but exceptional cases4 ,connection is then made to a current from the dry batteries in series so arranged as to allow completion of the circuit with a switch4 ,the current from a lighting system should not be used for ignition1 as there is danger from sparking in burning the fuse1 which may effect the results4 ,the apparatus is then ready for the test4 ,unquestionably the best method of taking data is by the use of co-ordinate paper and a plotting of the data with temperatures and time intervals as ordinates and abscissae4 ,such a graphic representation is shown in ,fig4 #be4 ,graph3 ,temperature-- ,c4 against ,time--,hours and ,minutes ,fig4 #be4 ,graphic ,method of ,recording ,bomb ,calorimeter ,results ,after the bomb is placed in the calorimeter1 and before the coal is ignited1 readings of the temperature of the water should be taken at one minute intervals for a period long enough to insure a constant rate of change1 and in this way determine the initial radiation4 ,the coal is then ignited by completing the circuit1 the temperature at the instant the circuit is closed being considered the temperature at the beginning of the combustion4 ,after ignition the readings should be taken at one-half minute intervals1 though because of the rapidity of the mercury's rise approximate readings only may be possible for at least a minute after the firing1 such readings1 however1 being sufficiently accurate for this period4 ,the one-half minute readings should be taken after ignition for five minutes1 and for1 say1 five minutes longer at minute intervals to determine accurately the final rate of radiation4 ,fig4 #be shows the results of such readings1 plotted in accordance with the method suggested4 ,it now remains to compute the results from this plotted data4 ,the radiation correction is first applied4 ,probably the most accurate manner of making such correction is by the use of ,pfaundler's method1 which is a modification of that of ,regnault4 ,this assumes that in starting with an initial rate of radiation1 as represented by the inclination of the line ,,ab1 ,fig4 #be1 and ending with a final radiation represented by the inclination of the line ,,cd1 ,fig4 #be1 that the rate of radiation for the intermediate temperatures between the points ,b and ,c are proportional to the initial and final rates4 ,that is1 the rate of radiation at a point midway between ,b and ,c will be the mean between the initial and final rates2 the rate of radiation at a point three-quarters of the distance between ,b and ,c would be the rate at ,b plus three-quarters of the difference in rates at ,b and ,c1 etc4 ,this method differs from ,regnault's in that the radiation was assumed by ,regnault to be in each case proportional to the difference in temperatures between the water of the calorimeter and the surrounding air plus a constant found for each experiment4 ,pfaundler's method is more simple than that of ,regnault1 and the results by the two methods are in practical agreement4 ,expressed as a formula1 ,pfaundler's method is1 though not in form given by him3 ,r' - ,r ,c ,n,r ------ 7,t - ,t7 7#ai7 ,t' - ,t ,where ,c correction in degree centigrade1 ,n number of intervals over which correction is made1 ,r initial radiation in degrees per interval1 ,r' final radiation in degrees per interval1 ,t average temperature for period through which initial radiation is computed1 ,t average temperature over period of combustion#ci1 ,t' average temperature over period through which final radiation is computed4#ci ,the application of this formula to ,fig4 #be is as follows3 ,as already stated1 the temperature at the beginning of combustion is the reading just before the current is turned on1 or ,b in ,fig4 #be4 ,the point ,c or the temperature at which combustion is presumably completed1 should be taken at a point which falls well within the established final rate of radiation1 and not at the maximum temperature that the thermometer indicates in the test1 unless it lies on the straight line determining the final radiation4 ,this is due to the fact that in certain instances local conditions will cause the thermometer to read higher than it should during the time that the bomb is transmitting heat to the water rapidly1 and at other times the maximum temperature might be lower than that which would be indicated were readings to be taken at intervals of less than one-half minute1 i4 e41 the point of maximum temperature will fall below the line determined by the final rate of radiation4 ,with this understanding ,,ab1 ,fig4 #be1 represents the time of initial radiation1 ,,bc the time of combustion1 and ,,cd the time of final radiation4 ,therefore to apply ,pfaundler's correction1 formula 7#ai71 to the data as represented by ,fig4 #be4 ,n #f1 ,r #j1 ,r' 4#ja1 ,t #bj4bi1 ,t' #bb4hc1 #bj4bi #bb4ed #bb4hd #bb4hh #bb4hg #bb4hf ,t ---------------------------------------- ----- #bb4cf #f 4#ja - #j ,c #fj -------------7#bb4cf - #bj4bi7 #bb4he - #bj4bi #f 4#jjh 4#jdh ,pfaundler's formula while simple is rather long4 ,mr4 ,e4 ,h4 ,peabody has devised a simpler formula with which1 under proper conditions1 the variation from correction as found by ,pfaundler's method is negligible4 ,it was noted throughout an extended series of calorimeter tests that the maximum temperature was reached by the thermometer slightly over one minute after the time of firing4 ,if this period between the time of firing and the maximum temperature reported was exactly one minute1 the radiation through this period would equal the radiation per one-half minute before firing plus the radiation per one-half minute after the maximum temperature is reached2 or1 the radiation through the one minute interval would be the average of the radiation per minute before firing and the radiation per minute after the maximum4 ,a plotted chart of temperatures would take the form of a curve of three straight lines 7,b1 ,c'1 ,d7 in ,fig4 #be4 ,under such conditions1 using the notation as in formula 7#ai7 the correction would become1 #b,r #b,r' ,c ------- 7,n - #b7,r'1 or ,r 7,n - #a7,r' 7#bj7 #b ,this formula may be generalized for conditions where the maximum temperature is reached after a period of more than one minute as follows3 ,let ,m the number of intervals between the time of firing and the maximum temperature4 ,then the radiation through this period will be an average of the radiation for ,m intervals before firing and for ,m intervals after the maximum is recorded1 or ,,mr ,,mr' ,m ,m ,c ------- 7,n - ,m7,r' - ,r 7,n - -7,r' 7#ba7 #b #b #b ,in the case of ,mr4 ,peabody's deductions ,m was found to be approximately #b and formula 7#ba7 becomes directly1 ,c ,r 7,n - #a7,r' or formula 7#bj74 ,the corrections to be made1 as secured by the use of this formula1 are very close to those secured by ,pfaundler's method1 where the point of maximum temperature is not more than five intervals later than the point of firing4 ,where a longer period than this is indicated in the chart of plotted temperatures1 the approximate formula should not be used4 ,as the period between firing and the maximum temperature is increased1 the plotted results are further and further away from the theoretical straight line curve4 ,where this period is not over five intervals1 or two and a half minutes1 an approximation of the straight line curve may be plotted by eye1 and ordinarily the radiation correction to be applied may be determined very closely from such an approximated curve4 ,peabody's approximate formula has been found from a number of tests to give results within 4#jjc degrees ,fahrenheit for the limits within which its application holds good as described4 ,the value of ,m1 which is not necessarily a whole number1 should be determined for each test1 though in all probability such a value is a constant for any individual calorimeter which is properly operated4 ,the correction for radiation as found on page #ahh is in all instances to be added to the range of temperature between the firing point and the point chosen from which the final radiation is calculated4 ,this corrected range multiplied by the water equivalent of the calorimeter gives the heat of combustion in calories of the coal burned in the calorimeter together with that evolved by the burning of the fuse wire4 ,the heat evolved by the burning of the fuse wire is found from the determination of the actual weight of wire burned and the heat of combustion of one milligram of the wire 7#a4g calories71 i4 e41 multiply the weight of wire used by #a4g1 the result being in gram calories or the heat required to raise one gram of water one degree centigrade4 ,other small corrections to be made are those for the formation of nitric acid and for the combustion of sulphur to sulphuric acid instead of sulphur dioxide1 due to the more complete combustion in the presence of oxygen than would be possible in the atmosphere4 ,to make these corrections the bomb of the calorimeter is carefully washed out with water after each test and the amount of acid determined from titrating this water with a standard solution of ammonia or of caustic soda1 all of the acid being assumed to be nitric acid4 ,each cubic centimeter of the ammonia titrating solution used is equivalent to a correction of #b4fe calories4 ,as part of acidity is due to the formation of sulphuric acid1 a further correction is necessary4 ,in burning sulphuric acid the heat evolved per gram of sulphur is #bbcj calories in excess of the heat which would be evolved if the sulphur burned to sulphur dioxide1 or #bb4c calories for each per cent of sulphur in the coal4 ,one cubic centimeter of the ammonia solution is equivalent to #j4jjbhf grams of sulphur as sulphuric acid1 or to #j4bhf #bb4c #f4ch calories4 ,it is evident therefore that after multiplying the number of cubic centimeters used in titrating by the heat factor for nitric acid 7#b4fe7 a further correction of #f4ch - #b4fe #c4gc is necessary for each cubic centimeter used in titrating sulphuric instead of nitric acid4 ,this correction will be #c4gc_/j4big #ac units for each #j4ja gram of sulphur in the coal4 ,the total correction therefore for the aqueous nitric and sulphuric acid is found by multiplying the ammonia by #b4fe and adding #ac calories for each #j4ja gram of sulphur in the coal4 ,this total correction is to be deducted from the heat value as found from the corrected range and the amount equivalent to the calorimeter4 ,after each test the pan in which the coal has been burned must be carefully examined to make sure that all of the sample has undergone complete combustion4 ,the presence of black specks ordinarily indicates unburned coal1 and often will be found where the coal contains bone or slate4 ,where such specks are found the tests should be repeated4 ,in testing any fuel where it is found difficult to completely consume a sample1 a weighed amount of naphthaline may be added1 the total weight of fuel and naphthaline being approximately one gram4 ,the naphthaline has a known heat of combustion1 samples for this purpose being obtainable from the ,united ,states ,bureau of ,standards1 and from the combined heat of combustion of the fuel and naphthaline that of the former may be readily computed4 ,the heat evolved in burning of a definite weight of standard naphthaline may also be used as a means of calibrating the calorimeter as a whole4 ,,combustion ,,of ,,coal ,the composition of coal varies over such a wide range1 and the methods of firing have to be altered so greatly to suit the various coals and the innumerable types of furnaces in which they are burned1 that any instructions given for the handling of different fuels must of necessity be of the most general character4 ,for each kind of coal there is some method of firing which will give the best results for each individual set of conditions4 ,general rules can be suggested1 but the best results can be obtained only by following such methods as experience and practice show to be the best suited to the specific conditions4 ,the question of draft is an all important factor4 ,if this be insufficient1 proper combustion is impossible1 as the suction in the furnace will not be great enough to draw the necessary amount of air through the fuel bed1 and the gases may pass off only partially consumed4 ,on the other hand1 an excessive draft may cause losses due to the excess quantities of air drawn through holes in the fire4 ,where coal is burned however1 there are rarely complaints from excessive draft1 as this can be and should be regulated by the boiler damper to give only the draft necessary for the particular rate of combustion desired4 ,the draft required for various kinds of fuel is treated in detail in the chapter on ,chimneys and ,draft4 ,in this chapter it will be assumed that the draft is at all times ample and that it is regulated to give the best results for each kind of coal4 ,,table #dj ,,anthracite ,,coal ,,sizes ,testing ,segments ,round ,mesh ,standard ,square ,mesh ,trade ,name ,through ,over ,through ,over ,inches ,inches ,inches ,inches ,broken #d-a_/b #c-a_/d #d #b-c_/d ,egg #c-a_/d #b-c_/h #b-c_/d #b ,stove #b-c_/h #a-e_/h #b #a-c_/h ,chestnut #a-e_/h #g_/h #a-c_/h #c_/d ,pea #g_/h #e_/h #c_/d #a_/b ,no4 #a ,buckwheat #e_/h #c_/h #a_/b #a_/d ,no4 #b ,buckwheat or ,rice #c_/h #c_/af #a_/d #a_/h ,no4 #c ,buckwheat or ,barley #c_/af #c_/cb #a_/h #a_/af ,anthracite--,anthracite coal is ordinarily marketed under the names and sizes given in ,table #dj4 ,the larger sizes of anthracite are rarely used for commercial steam generating purposes as the demand for domestic use now limits the supply4 ,in commercial plants the sizes generally found are ,nos4 #a1 #b and #c buckwheat4 ,in some plants where the finer sizes are used1 a small percentage of bituminous coal1 say1 #aj per cent1 is sometimes mixed with the anthracite and beneficial results secured both in economy and capacity4 ,anthracite coal should be fired evenly1 in small quantities and at frequent intervals4 ,if this method is not followed1 dead spots will appear in the fire1 and if the fire gets too irregular through burning in patches1 nothing can be done to remedy it until the fire is cleaned as a whole4 ,after this grade of fuel has been fired it should be left alone1 and the fire tools used as little as possible4 ,owing to the difficulty of igniting this fuel1 care must be taken in cleaning fires4 ,the intervals of cleaning will1 of course1 depend upon the nature of the coal and the rate of combustion4 ,with the small sizes and moderately high combustion rates1 fires will have to be cleaned twice on each eight-hour shift4 ,as the fires become dirty the thickness of the fuel bed will increase1 until this depth may be #ab or #ad inches just before a cleaning period4 ,in cleaning1 the following practice is usually followed3 ,the good coal on the forward half of the grate is pushed to the rear half1 and the refuse on the front portion either pulled out or dumped4 ,the good coal is then pulled forward onto the front part of the grate and the refuse on the rear section dumped4 ,the remaining good coal is then spread evenly over the whole grate surface and the fire built up with fresh coal4 ,a ratio of grate surface to heating surface of #a to from #ce to #dj will under ordinary conditions develop the rated capacity of a boiler when burning anthracite buckwheat4 ,where the finer sizes are used1 or where overloads are desirable1 however1 this ratio should preferably be #a to #be and a forced blast should be used4 ,grates #aj feet deep with a slope of #a inches to the foot can be handled comfortably with this class of fuel1 and grates #ab feet deep with the same slope can be successfully handled4 ,where grates over #h feet in depth are necessary1 shaking grates or overlapping dumping grates should be used4 ,dumping grates may be applied either for the whole grate surface or to the rear section4 ,air openings in the grate bars should be made from #c_/af inch in width for ,no4 #c buckwheat to #e_/af inch for ,no4 #a buckwheat4 ,it is important that these air openings be uniformly distributed over the whole surface to avoid blowing holes in the fire1 and it is for this reason that overlapping grates are recommended4 ,no air should be admitted over the fire4 ,steam is sometimes introduced into the ashpit to soften any clinker that may form1 but the quantity of steam should be limited to that required for this purpose4 ,the steam that may be used in a steam jet blower for securing blast will in certain instances assist in softening the clinker1 but a much greater quantity may be used by such an apparatus than is required for this purpose4 ,combustion arches sprung above the grates have proved of advantage in maintaining a high furnace temperature and in assisting in the ignition of fresh coal4 ,stacks used with forced blast should be of such size as to insure a slight suction in the furnace under any conditions of operation4 ,a blast up to #c inches of water should be available for the finer sizes supplied by engine driven fans1 automatically controlled by the boiler pressure4 ,the blast required will increase as the depth of the fuel bed increases1 and the slight suction should be maintained in the furnace by damper regulation4 ,the use of blast with the finer sizes causes rapid fouling of the heating surfaces of the boiler1 the dust often amounting to over #aj per cent of the total fuel fired4 ,economical disposal of dust and ashes is of the utmost importance in burning fuel of this nature4 ,provision should be made in the baffling of the boiler to accommodate and dispose of this dust4 ,whenever conditions permit1 the ashes can be economically disposed of by flushing them out with water4 ,bituminous ,coals--,there is no classification of bituminous coal as to size that holds good in all localities4 ,the ,american ,society of ,mechanical ,engineers suggests the following grading3 ,eastern ,bituminous ,coals-- 7,a7 ,run of mine coal2 the unscreened coal taken from the mine4 7,b7 ,lump coal2 that which passes over a bar-screen with openings #a inches wide4 7,c7 ,nut coal2 that which passes through a bar-screen with #a-;inch openings and over one with -inch openings4 7,d7 ,slack coal2 that which passes through a bar-screen with -inch openings4 ,western ,bituminous ,coals-- 7,e7 ,run of mine coal2 the unscreened coal taken from the mine4 7,f7 ,lump coal2 divided into #f-;inch1 #c-;inch and #a-;inch lump1 according to the diameter of the circular openings over which the respective grades pass2 also #f #c-;inch lump and #c #a-;inch lump1 according as the coal passes through a circular opening having the diameter of the larger figure and over that of the smaller diameter4 7,g7 ,nut coal2 divided into #c-;inch steam nut1 which passes through an opening #c inches diameter and over #a inches2 #a inch nut1 which passes through a #a-;inch diameter opening and over a -inch diameter opening2 -inch nut1 which passes through a -inch diameter opening and over a #e_/h-;inch diameter opening4 7,h7 ,screenings2 that which passes through a #a-;inch diameter opening4 ,as the variation in character of bituminous coals is much greater than in the anthracites1 any rules set down for their handling must be the more general4 ,the difficulties in burning bituminous coals with economy and with little or no smoke increases as the content of fixed carbon in the coal decreases4 ,it is their volatile content which causes the difficulties and it is essential that the furnaces be designed to properly handle this portion of the coal4 ,the fixed carbon will take care of itself1 provided the volatile matter is properly burned4 ,mr4 ,kent1 in his ,steam ,boiler ,economy1 described the action of bituminous coal after it is fired as follows3 ,the first thing that the fine fresh coal does is to choke the air spaces existing through the bed of coke1 thus shutting off the air supply which is needed to burn the gases produced from the fresh coal4 ,the next thing is a very rapid evaporation of moisture from the coal1 a chilling process1 which robs the furnace of heat4 ,next is the formation of water-gas by the chemical reaction1 ,c ,h#b,o ,,co #b;,h1 the steam being decomposed1 its oxygen burning the carbon of the coal to carbonic oxide1 and the hydrogen being liberated4 ,this reaction takes place when steam is brought in contact with highly heated carbon4 ,this also is a chilling process1 absorbing heat from the furnaces4 ,the two valuable fuel gases thus generated would give back all the heat absorbed in their formation if they could be burned1 but there is not enough air in the furnace to burn them4 ,admitting extra air through the fire door at this time will be of no service1 for the gases being comparatively cool cannot be burned unless the air is highly heated4 ,after all the moisture has been driven off from the coal1 the distillation of hydrocarbons begins1 and a considerable portion of them escapes unburned1 owing to the deficiency of hot air1 and to their being chilled by the relatively cool heating surfaces of the boiler4 ,during all this time great volumes of smoke are escaping from the chimney1 together with unburned hydrogen1 hydrocarbons1 and carbonic oxide1 all fuel gases1 while at the same time soot is being deposited on the heating surface1 diminishing its efficiency in transmitting heat to the water4 ,to burn these gases distilled from the coal1 it is necessary that they be brought into contact with air sufficiently heated to cause them to ignite1 that sufficient space be allowed for their mixture with the air1 and that sufficient time be allowed for their complete combustion before they strike the boiler heating surfaces1 since these surfaces are comparatively cool and will lower the temperature of the gases below their ignition point4 ,the air drawn through the fire by the draft suction is heated in its passage and heat is added by radiation from the hot brick surfaces of the furnace1 the air and volatile gases mixing as this increase in temperature is taking place4 ,thus in most instances is the first requirement fulfilled4 ,the element of space for the proper mixture of the gases with the air1 and of time in which combustion is to take place1 should be taken care of by sufficiently large combustion chambers4 ,certain bituminous coals1 owing to their high volatile content1 require that the air be heated to a higher temperature than it is possible for it to attain simply in its passage through the fire and by absorption from the side walls of the furnace4 ,such coals can be burned with the best results under fire brick arches4 ,such arches increase the temperature of the furnace and in this way maintain the heat that must be present for ignition and complete combustion of the fuels in question4 ,these fuels too1 sometimes require additional combustion space1 and an extension furnace will give this in addition to the required arches4 ,as stated1 the difficulty of burning bituminous coals successfully will increase with the increase in volatile matter4 ,this percentage of volatile will affect directly the depth of coal bed to be carried and the intervals of firing for the most satisfactory results4 ,the variation in the fuel over such wide ranges makes it impossible to definitely state the thickness of fires for all classes1 and experiment with the class of fuel in use is the best method of determining how that particular fuel should be handled4 ,the following suggestions1 which are not to be considered in any sense hard and fast rules1 may be of service for general operating conditions for hand firing3 ,semi-bituminous coals1 such as ,pocahontas1 ,new ,river1 ,clearfield1 etc41 require fires from #aj to #ad inches thick2 fresh coal should be fired at intervals of #aj to #bj minutes and sufficient coal charged at each firing to maintain a uniform thickness4 ,bituminous coals from ,pittsburgh ,region require fires from #d to #f inches thick1 and should be fired often in comparatively small charges4 ,kentucky1 ,tennessee1 ,ohio and ,illinois coals require a thickness from #d to #f inches4 ,free burning coals from ,rock ,springs1 ,wyoming1 require from #f to #h inches1 while the poorer grades of ,montana1 ,utah and ,washington bituminous coals require a depth of about #d inches4 ,in general as thin fires are found necessary1 the intervals of firing should be made more frequent and the quantity of coal fired at each interval smaller4 ,as thin fires become necessary due to the character of the coal1 the tendency to clinker will increase if the thickness be increased over that found to give the best results4 ,there are two general methods of hand firing3 #ast1 the spreading method2 and #bnd1 the coking method4 ,illustration3 ,babcock ,wilcox ,chain ,grate ,stoker ,in the spreading method but little fuel is fired at one time1 and is spread evenly over the fuel bed from front to rear4 ,where there is more than one firing door the doors should be fired alternately4 ,the advantage of alternate firing is the whole surface of the fire is not blanketed with green coal1 and steam is generated more uniformly than if all doors were fired at one time4 ,again1 a better combustion results due to the burning of more of the volatile matter directly after firing than where all doors are fired at one time4 ,in the coking method1 fresh coal is fired at considerable depth at the front of the grate and after it is partially coked it is pushed back into the furnace4 ,the object of such a method is the preserving of a bed of carbon at the rear of the grate1 in passing over which the volatile gases driven off from the green coal will be burned4 ,this method is particularly adaptable to a grate in which the gases are made to pass horizontally over the fire4 ,modern practice for hand firing leans more and more toward the spread firing method4 ,again the tendency is to work bituminous coal fires less than formerly4 ,a certain amount of slicing and raking may be necessary with either method of firing1 but in general1 the less the fire is worked the better the results4 ,lignites--,as the content of volatile matter and moisture in lignite is higher than in bituminous coal1 the difficulties encountered in burning them are greater4 ,a large combustion space is required and the best results are obtained where a furnace of the reverberatory type is used1 giving the gases a long travel before meeting the tube surfaces4 ,a fuel bed from #d to #f inches in depth can be maintained1 and the coal should be fired in small quantities by the alternate method4 ,above certain rates of combustion clinker forms rapidly1 and a steam jet in the ashpit for softening this clinker is often desirable4 ,a considerable draft should be available1 but it should be carefully regulated by the boiler damper to suit the condition of the fire4 ,smokelessness with hand firing with this class of fuel is a practical impossibility4 ,it has a strong tendency to foul the heating surfaces rapidly and these surfaces should be cleaned frequently4 ,shaking grates1 intelligently handled1 aid in cleaning the fires1 but their manipulation must be carefully watched to prevent good coal being lost in the ashpit4 ,stokers--,the term automatic stoker oftentimes conveys the erroneous impression that such an apparatus takes care of itself1 and it must be thoroughly understood that any stoker requires expert attention to as high if not higher degree than do hand-fired furnaces4 ,stoker-fired furnaces have many advantages over hand firing1 but where a stoker installation is contemplated there are many factors to be considered4 ,it is true that stokers feed coal to the fire automatically1 but if the coal has first to be fed to the stoker hopper by hand1 its automatic advantage is lost4 ,this is as true of the removal of ash from a stoker4 ,in a general way1 it may be stated that a stoker installation is not advantageous except possibly for diminishing smoke1 unless the automatic feature is carried to the handling of the coal and ash1 as where coal and ash handling apparatus is not installed there is no saving in labor4 ,in large plants1 however1 stokers used in conjunction with the modern methods of coal storage and coal and ash handling1 make possible a large labor saving4 ,in small plants the labor saving for stokers over hand-fired furnaces is negligible1 and the expense of the installation no less proportionately than in large plants4 ,stokers are1 therefore1 advisable in small plants only where the saving in fuel will be large1 or where the smoke question is important4 ,interest on investment1 repairs1 depreciation and steam required for blast and stoker drive must all be considered4 ,the upkeep cost will1 in general1 be higher than for hand-fired furnaces4 ,stokers1 however1 make possible the use of cheaper fuels with as high or higher economy than is obtainable under operating conditions in hand-fired furnaces with a better grade of fuel4 ,the better efficiency obtainable with a good stoker is due to more even and continuous firing as against the intermittent firing of hand-fired furnaces2 constant air supply as against a variation in this supply to meet varying furnace conditions in hand-fired furnaces2 and the doing away to a great extent with the necessity of working the fires4 ,stokers under ordinary operating conditions will give more nearly smokeless combustion than will hand-fired furnaces and for this reason must often be installed regardless of other considerations4 ,while a constant air supply for a given power is theoretically secured by the use of a stoker1 and in many instances the draft is automatically governed1 the air supply should1 nevertheless1 be as carefully watched and checked by flue gas analyses as in the case of hand-fired furnaces4 ,there is a tendency in all stokers to cause the loss of some good fuel or siftings in the ashpit1 but suitable arrangements may be made to reclaim this4 ,in respect to efficiency of combustion1 other conditions being equal1 there will be no appreciable difference with the different types of stokers1 provided that the proper type is used for the grade of fuel to be burned and the conditions of operation to be fulfilled4 ,no stoker will satisfactorily handle all classes of fuel1 and in making a selection1 care should be taken that the type is suited to the fuel and the operating conditions4 ,a cheap stoker is a poor investment4 ,only the best stoker suited to the conditions which are to be met should be adopted1 for if there is to be a saving1 it will more than cover the cost of the best over the cheaper stoker4 ,mechanical ,stokers are of three general types3 #ast1 overfeed2 #bnd1 underfeed2 and #crd1 traveling grate4 ,the traveling grate stokers are sometimes classed as overfeed but properly should be classed by themselves as under certain conditions they are of the underfeed rather than the overfeed type4 ,overfeed ,stokers in general may be divided into two classes1 the distinction being in the direction in which the coal is fed relative to the furnaces4 ,in one class the coal is fed into hoppers at the front end of the furnace onto grates with an inclination downward toward the rear of about #de degrees4 ,these grates are reciprocated1 being made to take alternately level and inclined positions and this motion gradually carries the fuel as it is burned toward the rear and bottom of the furnace4 ,at the bottom of the grates flat dumping sections are supplied for completing the combustion and for cleaning4 ,the fuel is partly burned or coked on the upper portion of the grates1 the volatile gases driven off in this process for a perfect action being ignited and burned in their passage over the bed of burning carbon lower on the grates1 or on becoming mixed with the hot gases in the furnace chamber4 ,in the second class the fuel is fed from the sides of the furnace for its full depth from front to rear onto grates inclined toward the center of the furnace4 ,it is moved by rocking bars and is gradually carried to the bottom and center of the furnace as combustion advances4 ,here some type of a so-called clinker breaker removes the refuse4 ,underfeed ,stokers are either horizontal or inclined4 ,the fuel is fed from underneath1 either continuously by a screw1 or intermittently by plungers4 ,the principle upon which these stokers base their claims for efficiency and smokelessness is that the green fuel is fed under the coked and burning coal1 the volatile gases from this fresh fuel being heated and ignited in their passage through the hottest portion of the fire on the top4 ,in the horizontal classes of underfeed stokers1 the action of a screw carries the fuel back through a retort from which it passes upward1 as the fuel above is consumed1 the ash being finally deposited on dead plates on either side of the retort1 from which it can be removed4 ,in the inclined class1 the refuse is carried downward to the rear of the furnace where there are dumping plates1 as in some of the overfeed types4 ,underfeed stokers are ordinarily operated with a forced blast1 this in some cases being operated by the same mechanism as the stoker drive1 thus automatically meeting the requirements of various combustion rates4 ,traveling ,grates are of the class best illustrated by chain grate stokers4 ,as implied by the name these consist of endless grates composed of short sections of bars1 passing over sprockets at the front and rear of the furnace4 ,coal is fed by gravity onto the forward end of the grates through suitable hoppers1 is ignited under ignition arches and is carried with the grate toward the rear of the furnace as its combustion progresses4 ,when operated properly1 the combustion is completed as the fire reaches the end of the grate and the refuse is carried over this rear end by the grate in making the turn over the rear sprocket4 ,in some cases auxiliary dumping grates at the rear of the chain grates are used with success4 ,chain grate stokers in general produce less smoke than either overfeed or underfeed types1 due to the fact that there are no cleaning periods necessary4 ,such periods occur with the latter types of stokers at intervals depending upon the character of the fuel used and the rate of combustion4 ,with chain grate stokers the cleaning is continuous and automatic1 and no periods occur when smoke will necessarily be produced4 ,in the earlier forms1 chain grates had an objectionable feature in that the admission of large amounts of excess air at the rear of the furnace through the grates was possible4 ,this objection has been largely overcome in recent models by the use of some such device as the bridge wall water box and suitable dampers4 ,a distinct advantage of chain grates over other types is that they can be withdrawn from the furnace for inspection or repairs without interfering in any way with the boiler setting4 ,this class of stoker is particularly successful in burning low grades of coal running high in ash and volatile matter which can only be burned with difficulty on the other types4 ,the cost of up-keep in a chain grate1 properly constructed and operated1 is low in comparison with the same cost for other stokers4 ,the ,babcock ,wilcox chain grate is representative of this design of stoker4 ,smoke--,the question of smoke and smokelessness in burning fuels has recently become a very important factor of the problem of combustion4 ,cities and communities throughout the country have passed ordinances relative to the quantities of smoke that may be emitted from a stack1 and the failure of operators to live up to the requirements of such ordinances1 resulting as it does in fines and annoyance1 has brought their attention forcibly to the matter4 ,the whole question of smoke and smokelessness is to a large extent a comparative one4 ,there are any number of plants burning a wide variety of fuels in ordinary hand-fired furnaces1 in extension furnaces and on automatic stokers that are operating under service conditions1 practically without smoke4 ,it is safe to say1 however1 that no plant will operate smokelessly under any and all conditions of service1 nor is there a plant in which the degree of smokelessness does not depend largely upon the intelligence of the operating force4 ,illustration3 ,fig4 #bf4 ,babcock ,wilcox ,boiler and ,superheater ,equipped with ,babcock ,wilcox ,chain ,grate ,stoker4 ,this ,setting has been ,particularly ,successful in ,minimizing ,smoke ,when a condition arises in a boiler room requiring the fires to be brought up quickly1 the operatives in handling certain types of stokers will use their slice bars freely to break up the green portion of the fire over the bed of partially burned coal4 ,in fact1 when a load is suddenly thrown on a station the steam pressure can often be maintained only in this way1 and such use of the slice bar will cause smoke with the very best type of stoker4 ,in a certain plant using a highly volatile coal and operating boilers equipped with ordinary hand-fired furnaces1 extension hand-fired furnaces and stokers1 in which the boilers with the different types of furnaces were on separate stacks1 a difference in smoke from the different types of furnaces was apparent at light loads1 but when a heavy load was thrown on the plant1 all three stacks would smoke to the same extent1 and it was impossible to judge which type of furnace was on one or the other of the stacks4 ,in hand-fired furnaces much can be accomplished by proper firing4 ,a combination of the alternate and spreading methods should be used1 the coal being fired evenly1 quickly1 lightly and often1 and the fires worked as little as possible4 ,smoke can be diminished by giving the gases a long travel under the action of heated brickwork before they strike the boiler heating surfaces4 ,air introduced over the fires and the use of heated arches1 etc41 for mingling the air with the gases distilled from the coal will also diminish smoke4 ,extension furnaces will undoubtedly lessen smoke where hand firing is used1 due to the increase in length of gas travel and the fact that this travel is partially under heated brickwork4 ,where hand-fired grates are immediately under the boiler tubes1 and a high volatile coal is used1 if sufficient combustion space is not provided the volatile gases1 distilled as soon as the coal is thrown on the fire1 strike the tube surfaces and are cooled below the burning point before they are wholly consumed and pass through as smoke4 ,with an extension furnace1 these volatile gases are acted upon by the radiant heat from the extension furnace arch and this heat1 together with the added length of travel causes their more complete combustion before striking the heating surfaces than in the former case4 ,smoke may be diminished by employing a baffle arrangement which gives the gases a fairly long travel under heated brickwork and by introducing air above the fire4 ,in many cases1 however1 special furnaces for smoke reduction are installed at the expense of capacity and economy4 ,from the standpoint of smokelessness1 undoubtedly the best results are obtained with a good stoker1 properly operated4 ,as stated above1 the best stoker will cause smoke under certain conditions4 ,intelligently handled1 however1 under ordinary operating conditions1 stoker-fired furnaces are much more nearly smokeless than those which are hand fired1 and are1 to all intents and purposes1 smokeless4 ,in practically all stoker installations there enters the element of time for combustion1 the volatile gases as they are distilled being acted upon by ignition or other arches before they strike the heating surfaces4 ,in many instances too1 stokers are installed with an extension beyond the boiler front1 which gives an added length of travel during which1 the gases are acted upon by the radiant heat from the ignition or supplementary arches1 and here again we see the long travel giving time for the volatile gases to be properly consumed4 ,to repeat1 it must be emphatically borne in mind that the question of smokelessness is largely one of degree1 and dependent to an extent much greater than is ordinarily appreciated upon the handling of the fuel and the furnaces by the operators1 be these furnaces hand fired or automatically fired4 ,illustration3 #cebj ,horse-power ,installation of ,babcock ,wilcox ,boilers at the ,portland ,railway1 ,light and ,power ,co41 ,portland1 ,ore4 ,these ,boilers are ,equipped with ,wood ,refuse ,extension ,furnaces at the ,front and ,oil ,burning ,furnaces at the ,mud ,drum ,end ,,solid ,,fuels ,,other ,,than ,,coal ,,and ,,their ,,combustion ,wood--,wood is vegetable tissue which has undergone no geological change4 ,usually the term is used to designate those compact substances familiarly known as tree trunks and limbs4 ,when newly cut1 wood contains moisture varying from #cj per cent to #ej per cent4 ,when dried for a period of about a year in the atmosphere1 the moisture content will be reduced to #ah or #bj per cent4 ,,table #da ,,ultimate ,,analyses ,,and ,,calorific ,,values ,,of ,,dry ,,wood 7,,gottlieb7 ,kind ,b4 t4 u4 of ,c ,h ,n ,o ,ash per ,wood ,pound ,oak #ej4af #f4jb #j4ji #dc4cf #j4cg #hcaf ,ash #di4ah #f4bg #j4jg #dc4ia #j4eg #hdhj ,elm #dh4ii #f4bj #j4jf #dd4be #j4ej #heaj ,beech #di4jf #f4aa #j4ji #dd4ag #j4eg #hcia ,birch #dh4hh #f4jf #j4aj #dd4fg #j4bi #hehf ,fir #ej4cf #e4ib #j4je #dc4ci #j4bh #ijfc ,pine #ej4ca #f4bj #j4jd #dc4jh #j4cg #iaec ,poplar #di4cg #f4ba #j4if #da4fj #a4hf #ghcddj ,willow #di4if #e4if #j4if #ci4ef #c4cg #gibfdj ,wood is usually classified as hard wood1 including oak1 maple1 hickory1 birch1 walnut and beech2 and soft wood1 including pine1 fir1 spruce1 elm1 chestnut1 poplar and willow4 ,contrary to general opinion1 the heat value per pound of soft wood is slightly greater than the same value per pound of hard wood4 ,table #da gives the chemical composition and the heat values of the common woods4 ,ordinarily the heating value of wood is considered equivalent to #j4d that of bituminous coal4 ,in considering the calorific value of wood as given in this table1 it is to be remembered that while this value is based on air-dried wood1 the moisture content is still about #bj per cent of the whole1 and the heat produced in burning it will be diminished by this amount and by the heat required to evaporate the moisture and superheat it to the temperature of the gases4 ,the heat so absorbed may be calculated by the formula giving the loss due to moisture in the fuel1 and the net calorific value determined4 ,in designing furnaces for burning wood1 the question resolves itself into3 #ast1 the essential elements to give maximum capacity and efficiency with this class of fuel2 and #bnd1 the construction which will entail the least labor in handling and feeding the fuel and removing the refuse after combustion4 ,wood1 as used commercially for steam generating purposes1 is usually a waste product from some industrial process4 ,at the present time refuse from lumber and sawmills forms by far the greater part of this class of fuel4 ,in such refuse the moisture may run as high as #fj per cent and the composition of the fuel may vary over wide ranges during different portions of the mill operation4 ,the fuel consists of sawdust1 hogged wood and slabs1 and the percentage of each of these constituents may vary greatly4 ,hogged wood is mill refuse and logs that have been passed through a hogging machine or macerator4 ,this machine1 through the action of revolving knives1 cuts or shreds the wood into a state in which it may readily be handled as fuel4 ,table #db gives the moisture content and heat value of typical sawmill refuse from various woods4 ,,table #db ,,moisture ,,and ,,calorific ,,value ,,of ,,sawmill ,,refuse ,per ,cent ,b4 t4 u4 ,kind of ,wood ,nature of ,refuse ,moisture per ,pound ,dry ,fuel ,mexican ,white ,pine ,sawdust and ,hog ,chips #ea4ij #ijbj ,yosemite ,sugar ,pine ,sawdust and ,hog ,chips #fb4he #ijaj ,redwood #ge1 ,sawdust1 ,box ,mill ,douglas ,fir #be ,refuse and ,hog #db4bj #higgda ,redwood ,sawdust and ,hog ,chips #eb4ih #ijdjda ,redwood ,sawdust and ,hog ,chips #di4aa #ibjdda ,fir1 ,hemlock1 ,spruce and ,cedar ,sawdust #db4jf #hidida ,it is essential in the burning of this class of fuel that a large combustion space be supplied1 and on account of the usually high moisture content there should be much heated brickwork to radiate heat to the fuel bed and thus evaporate the moisture4 ,extension furnaces of the proper size are usually essential for good results and when this fuel is used alone1 grates dropped to the floor line with an ashpit below give additional volume for combustion and space for maintaining a thick fuel bed4 ,a thick fuel bed is necessary in order to avoid excessive quantities of air passing through the boiler4 ,where the fuel consists of hogged wood and sawdust alone1 it is best to feed it automatically into the furnace through chutes on the top of the extension4 ,the best results are secured when the fuel is allowed to pile up in the furnace to a height of #c or #d feet in the form of a cone under each chute4 ,the fuel burns best when not disturbed in the furnace4 ,each fuel chute1 when a proper distance from the grates and with the piles maintained at their proper height1 will supply about #cj or #ce square feet of grate surface4 ,while large quantities of air are required for burning this fuel1 excess air is as harmful as with coal1 and care must be taken that such an excess is not admitted through fire doors or fuel chutes4 ,a strong natural draft usually is preferable to a blast with this fuel4 ,the action of blast is to make the regulation of the furnace conditions more difficult and to blow over unconsumed fuel on the heating surfaces and into the stack4 ,this unconsumed fuel settling in portions of the setting out of the direct path of the gases will have a tendency to ignite provided any air reaches it1 with results harmful to the setting and breeching connection4 ,this action is particularly objectionable if these particles are carried over into the base of a stack1 where they will settle below the point at which the flue enters and if ignited may cause the stack to become overheated and buckle4 ,whether natural draft or blast is used1 much of the fuel is carried onto the heating surfaces and these should be cleaned regularly to maintain a good efficiency4 ,collecting chambers in various portions of the setting should be provided for this unconsumed fuel1 and these should be kept clean4 ,with proper draft conditions1 #aej pounds of this fuel containing about #cj to #dj per cent of moisture can be burned per square foot of grate surface per hour1 and in a properly designed furnace one square foot of grate surface can develop from #e to #f boiler horse power4 ,where the wood contains #ej per cent of moisture or over1 it is not usually safe to figure on obtaining more than #c to #d horse power per square foot of grate surface4 ,dry sawdust1 chips and blocks are also used as fuel in many wood-working industries4 ,here1 as with the wet wood1 ample combustion space should be supplied1 but as this fuel is ordinarily kiln dried1 large brickwork surfaces in the furnace are not necessary for the evaporation of moisture in the fuel4 ,this fuel may be burned in extension furnaces though these are not required unless they are necessary to secure an added furnace volume1 to get in sufficient grate surface1 or where such an arrangement must be used to allow for a fuel bed of sufficient thickness4 ,depth of fuel bed with the dry fuel is as important as with the moist fuel4 ,if extension furnaces are used with this dry wood1 care must be taken in their design that there is no excessive throttling of the gases in the furnace1 or brickwork trouble will result4 ,in ,babcock ,wilcox boilers this fuel may be burned without extension furnaces1 provided that the boilers are set at a sufficient height to provide ample combustion space and to allow for proper depth of fuel bed4 ,sometimes this is gained by lowering the grates to the floor line and excavating for an ashpit4 ,where the fuel is largely sawdust1 it may be introduced over the fire doors through inclined chutes4 ,the old methods of handling and collecting sawdust by means of air suction and blast were such that the amount of air admitted through such chutes was excessive1 but with improved methods the amount of air so admitted may be reduced to a negligible quantity4 ,the blocks and refuse which cannot be handled through chutes may be fired through fire doors in the front of the boiler1 which should be made sufficiently large to accommodate the larger sizes of fuel4 ,as with wet fuel1 there will be a quantity of unconsumed wood carried over and the heating surfaces must be kept clean4 ,in a few localities cord wood is burned4 ,with this as with other classes of wood fuel1 a large combustion space is an essential feature4 ,the percentage of moisture in cord wood may make it necessary to use an extension furnace1 but ordinarily this is not required4 ,ample combustion space is in most cases secured by dropping the grates to the floor line1 large double-deck fire doors being supplied at the usual fire door level through which the wood is thrown by hand4 ,air is admitted under the grates through an excavated ashpit4 ,the side1 front and rear walls of the furnace should be corbelled out to cover about one-third of the total grate surface4 ,this prevents cold air from laneing up the sides of the furnace and also reduces the grate surface4 ,cord wood and slabs form an open fire through which the frictional loss of the air is much less than in the case of sawdust or hogged material4 ,the combustion rate with cord wood is1 therefore1 higher and the grate surface may be considerably reduced4 ,such wood is usually cut in lengths of #d feet or #d feet #f inches1 and the depth of the grates should be kept approximately #e feet to get the best results4 ,bagasse--,bagasse is the refuse of sugar cane from which the juice has been extracted by pressure between the rolls of the mill4 ,from the start of the sugar industry bagasse has been considered the natural fuel for sugar plantations1 and in view of the importance of the industry a word of history relative to the use of this fuel is not out of place4 ,when the manufacture of sugar was in its infancy the cane was passed through but a single mill and the defecation and concentration of the saccharine juice took place in a series of vessels mounted one after another over a common fire at one end and connected to a stack at the opposite end4 ,this primitive method was known in the ,english colonies as the ,open ,wall and in the ,spanish-,american countries as the ,jamaica ,train4 ,the evaporation and concentration of the juice in the open air and over a direct fire required such quantities of fuel1 and the bagasse1 in fact1 played such an important part in the manufacture of sugar1 that oftentimes the degree of extraction1 which was already low1 would be sacrificed to the necessity of obtaining a bagasse that might be readily burned4 ,the furnaces in use with these methods were as primitive as the rest of the apparatus1 and the bagasse could be burned in them only by first drying it4 ,this naturally required an enormous quantity of handling of the fuel in spreading and collecting and frequently entailed a shutting down of the mill1 because a shower would spoil the supply which had been dried4 ,the difficulties arising from the necessity of drying this fuel caused a widespread attempt on the part of inventors to the turning out of a furnace which would successfully burn green bagasse4 ,some of the designs were more or less clever1 and about the year #ahhj several such green bagasse furnaces were installed4 ,these did not come up to expectations1 however1 and almost invariably they were abandoned and recourse had to be taken to the old method of drying in the sun4 ,from #ahhj the new era in the sugar industry may be dated4 ,slavery was almost universally abolished and it became necessary to pay for labor4 ,the cost of production was thus increased1 while growing competition of ,european beet sugar lowered the prices4 ,the only remedy for the new state of affairs was the cheapening of the production by the increase of extraction and improvement in manufacture4 ,the double mill took the place of the single1 the open wall method of extraction was replaced by vacuum evaporative apparatus and centrifugal machines were introduced to do the work of the great curing houses4 ,as opposed to these improvements1 however1 the steam plants remained as they started1 consisting of double flue boilers externally fired with dry bagasse4 ,on several of the plantations horizontal multitubular boilers externally fired were installed and at the time were considered the acme of perfection4 ,numerous attempts were made to burn the bagasse green1 among others the step grates imported from ,louisiana and known as the ,leon ,marie furnaces1 but satisfactory results were obtained in none of the appliances tried4 ,the ,babcock ,wilcox ,co4 at this time turned their attention to the problem with the results which ultimately led to its solution4 ,their ,new ,orleans representative1 ,mr4 ,frederick ,cook1 invented a hot forced blast bagasse furnace and conveyed the patent rights to this company4 ,this furnace while not as efficient as the standard of to-day1 and expensive in its construction1 did1 nevertheless1 burn the bagasse green and enabled the boilers to develop their normal rated capacity4 ,the first furnace of this type was installed at the ,southwood and ,mt4 ,houmas plantations and on a small plantation in ,florida4 ,about the year #ahhh two furnaces were erected in ,cuba1 one on the plantation ,senado and the other at the ,central ,hormiguero4 ,the results obtained with these furnaces were so remarkable in comparison with what had previously been accomplished that the company was overwhelmed with orders4 ,the expense of auxiliary fuel1 usually wood1 which was costly and indispensable in rainy weather1 was done away with and as the mill could be operated on bagasse alone1 the steam production and the factory work could be regulated with natural increase in daily output4 ,progress and improvement in the manufacture itself was going on at a remarkable rate1 the single grinding had been replaced by a double grinding1 this in turn by a third grinding1 and finally the maceration and dilution of the bagasse was carried to the extraction of practically the last trace of sugar contained in it4 ,the quantity of juice to be treated was increased in this way #bj or #cj per cent but was accompanied by the reduction to a minimum of the bagasse available as a fuel1 and led to demands upon the furnace beyond its capacity4 ,with the improvements in the manufacture1 planters had been compelled to make enormous sacrifices to change radically their systems1 and the heavy disbursement necessary for mill apparatus left few in a financial position to make costly installations of good furnaces4 ,the necessity of turning to something cheap in furnace construction but which was nevertheless better than the early method of burning the fuel dry led to the invention of numerous furnaces by all classes of engineers regardless of their knowledge of the subject and based upon no experience4 ,none of the furnaces thus produced were in any sense inventions but were more or less barefaced infringements of the patents of ,the ,babcock ,wilcox ,co4 ,as the company could not protect its rights without hurting its clients1 who in many cases against their own will were infringing upon these patents1 and as on the other hand they were anxious to do something to meet the wants of the planters1 a series of experiments were started1 at their own rather than at their customers' expense1 with a view to developing a furnace which1 without being as expensive1 would still fulfill all the requirements of the manufacturer4 ,the result was the cold blast green bagasse furnace which is now offered1 and it has been adopted as standard for this class of work after years of study and observation in our installations in the sugar countries of the world4 ,such a furnace is described later in considering the combustion of bagasse4 ,composition and ,calorific ,value of ,bagasse--,the proportion of fiber contained in the cane and density of the juice are important factors in the relation the bagasse fuel will have to the total fuel necessary to generate the steam required in a mill's operation4 ,a cane rich in wood fiber produces more bagasse than a poor one and a thicker juice is subject to a higher degree of dilution than one not so rich4 ,besides the percentage of bagasse in the cane1 its physical condition has a bearing on its calorific value4 ,the factors here entering are the age at which the cane must be cut1 the locality in which it is grown1 etc4 ,from the analysis of any sample of bagasse its approximate calorific value may be calculated from the formula1 #heej;,f #gaai,s #fgej;,g - #igb,w ,b4 t4 u4 per pound bagasse ---------------------------- 7#bb7 #ajj ,where ,f per cent of fiber in cane1 ,s per cent sucrose1 ,g per cent glucose1 ,w per cent water4 ,this formula gives the total available heat per pound of bagasse1 that is1 the heat generated per pound less the heat required to evaporate its moisture and superheat the steam thus formed to the temperature of the stack gases4 ,three samples of bagasse in which the ash is assumed to be #c per cent give from the formula3 ,f #ej ,s and ,g #d4e ,w #db4e ,b4 t4 u4 #dahc ,f #dj ,s and ,g #f4j ,w #ea4j ,b4 t4 u4 #ccea ,f #cc4c ,s and ,g #g4j ,w #ef4g ,b4 t4 u4 #bgig ,a sample of ,java bagasse having ,f #df4e1 ,s #d4ej1 ,g #j4e1 ,w #dg4e gives ,b4 t4 u4 #chfh4 ,these figures show that the dryer the bagasse is crushed1 the higher the calorific value1 though this is accompanied by a decrease in sucrose4 ,the explanation lies in the fact that the presence of sucrose in an analysis is accompanied by a definite amount of water1 and that the residual juice contains sufficient organic substance to evaporate the water present when a fuel is burned in a furnace4 ,for example1 assume the residual juice 7#ajj per cent7 to contain #ab per cent organic matter4 ,from the constant in formula1 #abgaai 7#ajj-ab7igb ------- #hed4c and ------------ #hee4d4 #ajj #ajj ,that is1 the moisture in a juice containing #ab per cent of sugar will be evaporated by the heat developed by the combustion of the contained sugar4 ,it would1 therefore1 appear that a bagasse containing such juice has a calorific value due only to its fiber content4 ,this is1 of course1 true only where the highest products of oxidization are formed during the combustion of the organic matter4 ,this is not strictly the case1 especially with a bagasse of a high moisture content which will not burn properly but which smoulders and produces a large quantity of products of destructive distillation1 chiefly heavy hydrocarbons1 which escape unburnt4 ,the reasoning1 however1 is sufficient to explain the steam making properties of bagasse of a low sucrose content1 such as are secured in ,java1 as when the sucrose content is lower1 the heat value is increased by extracting more juice1 and hence more sugar from it4 ,the sugar operations in ,java exemplify this and show that with a high dilution by maceration and heavy pressure the bagasse meets all of the steam requirements of the mills without auxiliary fuel4 ,a high percentage of silica or salts in bagasse has sometimes been ascribed as the reason for the tendency to smoulder in certain cases of soft fiber bagasse4 ,this1 however1 is due to the large moisture content of the sample resulting directly from the nature of the cane4 ,soluble salts in the bagasse has also been given as the explanation of such smouldering action of the fire1 but here too the explanation lies solely in the high moisture content1 this resulting in the development of only sufficient heat to evaporate the moisture4 ,,table #dc ,,analyses ,,and ,,calorific ,,values ,,of ,,bagasse ---------------------------------------- ----------------------------- ---------------------------------------- -------------------- ,b4t4u4 per ,source ,moisture ,c ,h ,o ,n ,ash ,pound ,dry ,bagasse ---------------------------------------- -------------------- ,cuba #ea4ej #dc4ae #f4jj #dg4ie #b4ij #gihe ,cuba #di4aj #dc4gd #f4jh #dh4fa #a4eg #hcjj ,cuba #db4ej #dc4fa #f4jf #dh4de #a4hh #hbdj ,cuba #ea4fa #df4hj #e4cd #df4ce #a4ea ,cuba #eb4hj #df4gh #e4gd #de4ch #b4aj ,porto ,rico #da4fj #dd4bh #f4ff #dg4aj #j4da #a4ce #hcei ,porto ,rico #dc4ej #dd4ba #f4ca #dg4gb #j4da #a4ce #hchf ,porto ,rico #dd4bj #dd4ib #f4bg #df4ej #j4da #a4ij #hchj ,louisiana #eb4aj #b4bg #hbcj ,louisiana #ed4jj #hcgj ,louisiana #ea4hj #hcga ,java #df4jc #f4ef #de4ee #j4ah #a4fh #hfha ---------------------------------------- -------------------- ---------------------------------------- ----------------------------- ,table #dc gives the analyses and heat values of bagasse from various localities4 ,table #dd gives the value of mill bagasse at different extractions1 which data may be of service in making approximations as to its fuel value as compared with that of other fuels4 ,,table #dd ,,value ,,of ,,one ,,pound ,,of ,,mill ,,bagasse ,,at ,,different ,,extractions #a3 ,per ,cent ,extraction of ,weight of ,cane #b3 ,per ,cent ,moisture in ,bagasse #c3 ,per ,cent in ,bagasse #d3 ,fuel ,value1 ,b4 t4 u4 #e3 ,per ,cent in ,bagasse #f3 ,fuel ,value1 ,b4 t4 u4 #g3 ,per ,cent in ,bagasse #h3 ,fuel ,value1 ,b4 t4 u4 #i3 ,total ,heat ,developed per ,pound of ,bagasse #aj3 ,heat ,required to ,evaporate ,moisture#db #aa3 ,heat ,available for ,steam ,generation #ab3 ,pounds of ,bagasse ,equivalent to one ,pound of ,coal of #ad1jjj ,b4 t4 u4 ---------------------------------------- ------------------------ ---------------------------------------- ---------------- ,b4t4u4 ,value per ,fiber ,sugar ,molasses ,pound of ,bagasse --------------------------------------- #a #b #c #d #e #f #g #h #i #aj #aa #ab ---------------------------------------- ----------- ,,based ,,upon ,,cane ,,of #ab ,,per ,,cent ,,fiber ,,and ,,juice ,,containing #ah ,,per ,,cent ,,of ,,solid ,,matter4 ,,representing ,,tropical ,,conditions ---------------------------------------- ----------- #ge #db4fddh4jjciiff4bddea #c4abbag #dffd #ebe #daci #c4ch #gg #ci4bbeb4agdcdce4gddad #b4hgbjj #dieh #dhc #ddge #c4ac #gi #ce4aeeg4addgege4adcga #b4egagi #ecjg #dcc #dhgd #b4hg #ha #cj4bafc4afebehd4dbcai #b4baaed #egca #cgb #ecei #b4fa #hc #bd4abgj4eiehggc4ecbef #a4gfabb #fbee #big #eieh #b4ce #he #af4bjhj4jjfffjb4djagc #a4bj #hc #fiaf #bjj #fgaf #b4jh ---------------------------------------- ----------- ,,based ,,upon ,,cane ,,of #aj ,,per ,,cent ,,fiber ,,and ,,juice ,,containing #ae ,,per ,,cent ,,of ,,solid ,,matter4 ,,representing ,,louisiana ,,conditions ---------------------------------------- ----------- #ge #ea4jjdj4jjcccjf4jjdcc #c4jjbji #cigb #fgh #cbid #d4be #gg #dh4jgdc4decfage4ffdji #b4hbaif #dbbb #eib #cfcj #c4hf #gi #dd4ebdg4fbcifde4bdcgh #b4fbahb #debd #edh #cigf #c4eb #ha #dj4aheb4fcdchad4gccdb #b4cfafd #dhhg #die #dcib #c4ai #hc #ce4jjeh4hbdhigd4abbih #b4jfadc #edcf #dca #ejje #b4hj #he #bh4ccff4fgeeejc4ccbda #a4fgaaf #eijg #cdi #eeeh #b4eb ---------------------------------------- ----------- ---------------------------------------- ------------------------ ,furnace ,design and the ,combustion of ,bagasse--,with the advance in sugar manufacture there came1 as described1 a decrease in the amount of bagasse available for fuel4 ,as the general efficiency of a plant of this description is measured by the amount of auxiliary fuel required per ton of cane1 the relative importance of the furnace design for the burning of this fuel is apparent4 ,in modern practice1 under certain conditions of mill operation1 and with bagasse of certain physical properties1 the bagasse available from the cane ground will meet the total steam requirements of the plant as a whole2 such conditions prevail1 as described1 in ,java4 ,in the ,united ,states1 ,cuba1 ,porto ,rico and like countries1 however1 auxiliary fuel is almost universally a necessity4 ,the amount will vary1 depending to a great extent upon the proportion of fiber in the cane1 which varies widely with the locality and with the age at which it is cut1 and to a lesser extent upon the degree of purity of the manufactured sugar1 the use of the maceration water and the efficiency of the mill apparatus as a whole4 ,illustration3 ,fig4 #bg4 ,babcock ,wilcox ,boiler ,set with ,green ,bagasse ,furnace ,experience has shown that this fuel may be burned with the best results in large quantities4 ,a given amount of bagasse burned in one furnace between two boilers will give better results than the same quantity burned in a number of smaller furnaces4 ,an objection has been raised against such practice on the grounds that the necessity of shutting down two boiler units when it is necessary for any reason to take off a furnace1 requires a larger combined boiler capacity to insure continuity of service4 ,as a matter of fact1 several small furnaces will cost considerably more than one large furnace1 and the saving in original furnace cost by such an installation1 taken in conjunction with the added efficiency of the larger furnace over the small1 will probably more than offset the cost of additional boiler units for spares4 ,the essential features in furnace design for this class of fuel are ample combustion space and a length of gas travel sufficient to enable the gases to be completely burned before the boiler heating surfaces are encountered4 ,experience has shown that better results are secured where the fuel is burned on a hearth rather than on grates1 the objection to the latter method being that the air for combustion enters largely around the edges1 where the fuel pile is thinnest4 ,when burned on a hearth the air for combustion is introduced into the furnace through several rows of tuyeres placed above and symmetrically around the hearth4 ,an arrangement of such tuyeres over a grate1 and a proper manipulation of the ashpit doors1 will overcome largely the objection to grates and at the same time enable other fuel to be burned in the furnace when necessary4 ,this arrangement of grates and tuyeres is probably the better from a commercially efficient standpoint4 ,where the air is admitted through tuyeres over the grate or hearth line1 it impinges on the fuel pile as a whole and causes a uniform combustion4 ,such tuyeres connect with an annular space in which1 where a blast is used1 the air pressure is controlled by a blower4 ,all experience with this class of fuel indicates that the best results are secured with high combustion rates4 ,with a natural draft in the furnace of1 say1 three-tenths inch of water1 a combustion rate of from #bej to #cjj pounds per square foot of grate surface per hour may be obtained4 ,with a blast of1 say1 five-tenths inch of water1 this rate can be increased to #dej pounds per square foot of grate surface per hour4 ,these rates apply to bagasse as fired containing approximately #ej per cent of moisture4 ,it would appear that the most economical results are secured with a combustion rate of approximately #cjj pounds per square foot per hour which1 as stated1 may be obtained with natural draft4 ,where a natural draft is available sufficient to give such a rate1 it is in general to be preferred to a blast4 ,fig4 #bg shows a typical bagasse furnace with which very satisfactory results have been obtained4 ,the design of this furnace may be altered to suit the boilers to which it is connected4 ,it may be changed slightly in its proportions and in certain instances in its position relative to the boiler4 ,the furnace as shown is essentially a bagasse furnace and may be modified somewhat to accommodate auxiliary fuel4 ,the fuel is ignited in a pit ,a on a hearth which is ordinarily elliptical in shape4 ,air for combustion is admitted through the tuyeres ,b connected to an annular space ,c through which the amount of air is controlled4 ,above the pit the furnace widens out to form a combustion space ,d which has a cylindrical or spherical roof with its top ordinarily from #aa to #ac feet above the floor4 ,the gases pass from this space horizontally to a second combustion chamber ,e from which they are led through arches ,f to the boiler4 ,the arrangement of such arches is modified to suit the boiler or boilers with which the furnace is operated4 ,a furnace of such design embodies the essential features of ample combustion space and long gas travel4 ,the fuel should be fed to the furnace through an opening in the roof above the pit by some mechanical means which will insure a constant fuel feed and at the same time prevent the inrush of cold air into the furnace4 ,this class of fuel deposits a considerable quantity of dust1 which if not removed promptly will fuse into a hard glass-like clinker4 ,ample provision should be made for the removal of such dust from the furnace1 the gas ducts and the boiler setting1 and these should be thoroughly cleaned once in #bd hours4 ,table #de gives the results of several tests on ,babcock ,wilcox boilers using fuel of this character4 ,,table #de ,,tests ,,of ,,babcock ,,wilcox ,,boilers ,,with ,,green ,,bagasse ,duration of ,test ,hours #ab #aj #aj #aj ,rated ,capacity of ,boiler ,horse ,power #cai #cai #cai #cai ,grate ,surface ,square ,feet #cc #cc #af4e #af4e ,draft in ,furnace ,inches 4#cj 4#bh 4#bi 4#bg ,draft at ,damper ,inches 4#dg 4#de 4#df 4#dh ,blast under ,grates ,inches 444 444 444 4#cd ,temperature of ,exit ,gases ,degrees ,f4 #ecf #eda #ebb #edg _/,,co#b ,per ,cent #ac4h #ab4f #aa4g #ab4h ,flue ,gas ,analysis ,o ,per ,cent #e4i #g4f #h4b #f4i ,,co ,per ,cent #j4j #j4j #j4j #j4j ,bagasse per ,hour as ,fired ,pounds #dihj #ddgi #ejdj #eehf ,moisture in ,bagasse ,per ,cent #eb4ci #eb4ic #ea4hd #ea4ga ,dry ,bagasse per ,hour ,pounds #bcga #bajh #bdbg #bfig ,dry ,bagasse per ,square ,foot of ,grate ,surface per ,hour ,pounds #ga4i #fc4i #adg4a #afc4d ,water per ,hour from and at #bab ,degrees ,pounds #ajada #ihej #ajdcj #aabbi ,per ,cent of ,rated ,capacity ,developed ,per ,cent #ib4a #hi4b #id4g #ajb4j ,tan ,bark--,tan bark1 or spent tan1 is the fibrous portion of bark remaining after use in the tanning industry4 ,it is usually very high in its moisture content1 a number of samples giving an average of #fe per cent or about two-thirds of the total weight of the fuel4 ,the weight of the spent tan is about #b4ac times as great as the weight of the bark ground4 ,in calorific value an average of #aj samples gives #iejj ,b4 t4 u4 per pound dry4#dc ,the available heat per pound as fired1 owing to the great percentage of moisture usually found1 will be approximately #bgjj ,b4 t4 u4 ,since the weight of the spent tan as fired is #b4ac as great as the weight of the bark as ground at the mill1 one pound of ground bark produces an available heat of approximately #egjj ,b4 t4 u4 ,relative to bituminous coal1 a ton of bark is equivalent to #j4d ton of coal4 ,an average chemical analysis of the bark is1 carbon #ea4h per cent1 hydrogen #f4jd1 oxygen #dj4gd1 ash #a4db4 ,tan bark is burned in isolated cases and in general the remarks on burning wet wood fuel apply to its combustion4 ,the essential features are a large combustion space1 large areas of heated brickwork radiating to the fuel bed1 and draft sufficient for high combustion rates4 ,the ratings obtainable with this class of fuel will not be as high as with wet wood fuel1 because of the heat value and the excessive moisture content4 ,mr4 ,d4 ,m4 ,meyers found in a series of experiments that an average of from #a4e to #b4jh horse power could be developed per square foot of grate surface with horizontal return tubular boilers4 ,this horse power would vary considerably with the method in which the spent tan was fired4 ,illustration3 #fhf ,horse-power ,babcock ,wilcox ,boiler and ,superheater in ,course of ,erection at the ,quincy1 ,mass41 ,station of the ,bay ,state ,street ,railway ,co4 ,,liquid ,,fuels ,,and ,,their ,,combustion ,petroleum is practically the only liquid fuel sufficiently abundant and cheap to be used for the generation of steam4 ,it possesses many advantages over coal and is extensively used in many localities4 ,there are three kinds of petroleum in use1 namely those yielding on distillation3 #ast1 paraffin2 #bnd1 asphalt2 #crd1 olefine4 ,to the first group belong the oils of the ,appalachian ,range and the ,middle ,west of the ,united ,states4 ,these are a dark brown in color with a greenish tinge4 ,upon their distillation such a variety of valuable light oils are obtained that their use as fuel is prohibitive because of price4 ,to the second group belong the oils found in ,texas and ,california4 ,these vary in color from a reddish brown to a jet black and are used very largely as fuel4 ,the third group comprises the oils from ,russia1 which1 like the second1 are used largely for fuel purposes4 ,the light and easily ignited constituents of petroleum1 such as naphtha1 gasolene and kerosene1 are oftentimes driven off by a partial distillation1 these products being of greater value for other purposes than for use as fuel4 ,this partial distillation does not decrease the value of petroleum as a fuel2 in fact1 the residuum known in trade as fuel oil has a slightly higher calorific value than petroleum and because of its higher flash point1 it may be more safely handled4 ,statements made with reference to petroleum apply as well to fuel oil4 ,in general crude oil consists of carbon and hydrogen1 though it also contains varying quantities of moisture1 sulphur1 nitrogen1 arsenic1 phosphorus and silt4 ,the moisture contained may vary from less than #a to over #cj per cent1 depending upon the care taken to separate the water from the oil in pumping from the well4 ,as in any fuel1 this moisture affects the available heat of the oil1 and in contracting for the purchase of fuel of this nature it is well to limit the per cent of moisture it may contain4 ,a large portion of any contained moisture can be separated by settling and for this reason sufficient storage capacity should be supplied to provide time for such action4 ,a method of obtaining approximately the percentage of moisture in crude oil which may be used successfully1 particularly with lighter oils1 is as follows4 ,a burette graduated into #bjj divisions is filled to the #ajj mark with gasolene1 and the remaining #ajj divisions with the oil1 which should be slightly warmed before mixing4 ,the two are then shaken together and any shrinkage below the #bjj mark filled up with oil4 ,the mixture should then be allowed to stand in a warm place for #bd hours1 during which the water and silt will settle to the bottom4 ,their percentage by volume can then be correctly read on the burette divisions1 and the percentage by weight calculated from the specific gravities4 ,this method is exceedingly approximate and where accurate results are required it should not be used4 ,for such work1 the distillation method should be used as follows3 ,gradually heat #ajj cubic centimeters of the oil in a distillation flask to a temperature of #aej degrees centigrade2 collect the distillate in a graduated tube and measure the resulting water4 ,such a method insures complete removal of water and reduces the error arising from the slight solubility of the water in gasolene4 ,two samples checked by the two methods for the amount of moisture present gave1 ,distillation ,dilution ,per ,cent ,per ,cent #h4ga #f4be #h4hb #f4bf ,,table #df ,,composition ,,and ,,calorific ,,value ,,of ,,various ,,oils ---------------------------------------- ---------------------------------------- ----------- ,kind of ,oil ,c ,h ,s ,o ,s4,g4,,fp ,h#b,o ,btu ,authority ---------------------------------------- ---------------------------------------- ----------- ,california1 ,coaling 4#ibgacd #agaag;,babcock ,wilcox ,co4 ,california1 ,bakersfield 4#ige #agfjj,wade ,california1 ,bakersfield #a4cj 4#iib #ahbeg,wade ,california1 ,kern ,river 4#iejadj #ahhde;,babcock ,wilcox ,co4 ,california1 ,los ,angeles #b4ef #ahcbh;,babcock ,wilcox ,co4 ,california1 ,los ,angeles 4#iegaif #ahhee;,babcock ,wilcox ,co4 ,california1 ,los ,angeles 4#igg 4#dj #ahbhj;,babcock ,wilcox ,co4 ,california1 ,monte ,christo 4#iffbje #ahhgh;,babcock ,wilcox ,co4 ,california1 ,whittier 4#ih 4#idd #a4jf #ahejg,wade ,california1 ,whittier 4#gb 4#icf #a4jf #ahbdj,wade ,california #he4jdaa4ebb4de 4#iidd #a4dj #aghga;,babcock ,wilcox ,co4 ,california #ha4ebaa4ea 4#eef4ibdd #bcj #ahffg,u4,s4,n4 ,liquid ,fuel ,board ,california 4#hg 4#ie #ahecc;,blasdale ,california 4#hiabeg #ahfee;,babcock ,wilcox ,co4 ,california #b4de 4#igc #a4ejdeagigf,o',neill ,california #b4df 4#ige #a4cb #ahajd,shepherd ,texas1 ,beaumont #hd4f #aj4i #a4fcb4hg 4#ibdahj #aijfj,u4,s4,n4 ,liquid ,fuel ,board ,texas1 ,beaumont #hc4c #ab4d 4#ejc4hc 4#ibfbaf #aidha,u4,s4,n4 ,liquid ,fuel ,board ,texas1 ,beaumont #he4j #ab4c #a4ge 4#ibdd #aijfj;,denton ,texas1 ,beaumont #hf4a #ab4c #a4fj 4#idb #bjaeb,sparkes ,texas1 ,beaumont 4#ijcbbb #aicdi;,babcock ,wilcox ,co4 ,texas1 ,sabine 4#icgadc #ahffb;,babcock ,wilcox ,co4 ,texas #hg4aeab4ccj4cb 4#ijhcgj #aicch,u4 ,s4 ,n4 ,texas #hg4biab4cbj4dc 4#iajcge #aifei,u4 ,s4 ,n4 ,ohio #hc4d #ad4g #j4f #a4c #aiehj ,pennsylvania #hd4i #ac4g #a4d 4#hhf #aibaj;,booth ,west ,virginia #hd4c #ad4a #a4f 4#hda #babdj ,mexico 4#ibaafb #ahhdj;,babcock ,wilcox ,co4 ,russia1 ,baku #hf4g #ab4i 4#hhd #bjfia;,booth ,russia1 ,novorossick #hd4i #aa4f #c4df #aideb;,booth ,russia1 ,caucasus #hf4f #ab4c #a4aj 4#ich #bjach ,java #hg4a #ab4j 4#i 4#ibc #baafc ,austria1 ,galicia #hb4b #ab4a #e4g 4#hgj #ahdaf ,italy1 ,parma #hd4j #ac4d #a4h 4#ghf ,borneo #he4g #aa4j #c4ca #aibdj,orde ---------------------------------------- ---------------------------------------- ----------- ,c ,per ,cent ,carbon ,h ,per ,cent ,hydrogen ,s ,per ,cent ,sulphur ,o ,per ,cent ,oxygen ,s4,g4 ,specific ,gravity ,,fp ,degrees ,flash ,point ,h#b,o ,per ,cent ,moisture ,btu ,b4 t4 u4 ,per ,pound ,calorific ,value--,a pound of petroleum usually has a calorific value of from #ah1jjj to #bb1jjj ,b4 t4 u4 ,if an ultimate analysis of an average sample be1 carbon #hd per cent1 hydrogen #ad per cent1 oxygen #b per cent1 and assuming that the oxygen is combined with its equivalent of hydrogen as water1 the analysis would become1 carbon #hd per cent1 hydrogen #ac4ge per cent1 water #b4be per cent1 and the heat value per pound including its contained water would be1 ,carbon 4#hdjj #ad1fjj #ab1bfd ,b4 t4 u4 ,hydrogen 4#acge #fb1ajj #h1fbe ,b4 t4 u4 ------9999,should be 4#acge x #fb1jjj #h1ebe ,total #bj1hhi ,b4 t4 u49999,would be ,total #bj1ghi ,the nitrogen in petroleum varies from #j4jjh to #a4j per cent1 while the sulphur varies from #j4jg to #c4j per cent4 ,table #df1 compiled from various sources1 gives the composition1 calorific value and other data relative to oil from different localities4 ,the flash point of crude oil is the temperature at which it gives off inflammable gases4 ,while information on the actual flash points of the various oils is meager1 it is1 nevertheless1 a question of importance in determining their availability as fuels4 ,in general it may be stated that the light oils have a low1 and the heavy oils a much higher flash point4 ,a division is sometimes made at oils having a specific gravity of #j4he1 with a statement that where the specific gravity is below this point the flash point is below #fj degrees ,fahrenheit1 and where it is above1 the flash point is above #fj degrees ,fahrenheit4 ,there are1 however1 many exceptions to this rule4 ,as the flash point is lower the danger of ignition or explosion becomes greater1 and the utmost care should be taken in handling the oils with a low flash point to avoid this danger4 ,on the other hand1 because the flash point is high is no justification for carelessness in handling those fuels4 ,with proper precautions taken1 in general1 the use of oil as fuel is practically as safe as the use of coal4 ,gravity of ,oils--,oils are frequently classified according to their gravity as indicated by the ,beaume hydrometer scale4 ,such a classification is by no means an accurate measure of their relative calorific values4 ,petroleum as ,compared with ,coal--,the advantages of the use of oil fuel over coal may be summarized as follows3 #ast4 ,the cost of handling is much lower1 the oil being fed by simple mechanical means1 resulting in1 #bnd4 ,a general labor saving throughout the plant in the elimination of stokers1 coal passers1 ash handlers1 etc4 #crd4 ,for equal heat value1 oil occupies very much less space than coal4 ,this storage space may be at a distance from the boiler without detriment4 #dth4 ,higher efficiencies and capacities are obtainable with oil than with coal4 ,the combustion is more perfect as the excess air is reduced to a minimum2 the furnace temperature may be kept practically constant as the furnace doors need not be opened for cleaning or working fires2 smoke may be eliminated with the consequent increased cleanliness of the heating surfaces4 #eth4 ,the intensity of the fire can be almost instantaneously regulated to meet load fluctuations4 #fth4 ,oil when stored does not lose in calorific value as does coal1 nor are there any difficulties arising from disintegration1 such as may be found when coal is stored4 #gth4 ,cleanliness and freedom from dust and ashes in the boiler room with a consequent saving in wear and tear on machinery2 little or no damage to surrounding property due to such dust4 ,the disadvantages of oil are3 #ast4 ,the necessity that the oil have a reasonably high flash point to minimize the danger of explosions4 #bnd4 ,city or town ordinances may impose burdensome conditions relative to location and isolation of storage tanks1 which in the case of a plant situated in a congested portion of the city1 might make use of this fuel prohibitive4 #crd4 ,unless the boilers and furnaces are especially adapted for the use of this fuel1 the boiler upkeep cost will be higher than if coal were used4 ,this objection can be entirely obviated1 however1 if the installation is entrusted to those who have had experience in the work1 and the operation of a properly designed plant is placed in the hands of intelligent labor4 ,,table #dg ,,relative ,,value ,,of ,,coal ,,and ,,oil ,,fuel ---------------------------------------- ---------------------------- ,gross ,net ,net ,water ,evaporated from and at ,boiler ,boiler ,evap- #bab ,degrees ,fahrenheit per ,pound of ,coal ,effic-,effici- oration--------------------------------- ------- iencyency#df from with with and at ,oil ,oil #bab #e #f #g #h #i #aj #aa #ab ,fuel ,fuel ,degrees ,fahren- heit ---------------------------------------- per ,pound ,pounds of ,oil ,equal to ,one ,pound of ,coal of ,oil ---------------------------------------- --------------------- #gc #ga #ac4ed 4#cfic4ddca4eagj4eiji4ffdg4gchf4habd4hhf c #gd #gb #ac4gc 4#cfdb4dcgj4ejii4ehbg4feef4gbhc4hjaa4hgd j #ge #gc #ac4ib 4#ceib4dcaj4ejbi4egdg4fdff4gahd4gijc4hfb a #gf #gd #ad4aa 4#cedd4dbec4difa4efgj4fcgh4gjhg4ggif4hej e #gg #ge #ad4cj 4#cdig4daif4dhie4eeid4fbid4fiic4gfib4hci b #gh #gf #ad4di 4#cdea4dada4dhca4eeba4fbaa4fija4geia4hbh a #gi #gg #ad4fh 4#cdjf4djhg4dgfh4edej4faca4fhab4gdic4hag d #hj #gh #ad4hg 4#ccfc4djce4dgjh4echj4fjec4fgbe4gcih4hjg j #ha #gi #ae4jf 4#ccbj4cihd4dfdh4ecab4eigf4ffdj4gcjd4gif h #hb #hj #ae4be 4#cbgi4cicd4deij4ebdf4eijb4feeg4gbac4ghf i #hc #ha #ae4dd 4#cbch4chhf4decd4eaha4ehbi4fddg4gabe4ggg b ---------------------------------------- --------------------- ,net ,evap- oration from and at #bab ,barrels of ,oil ,equal to ,one ,ton of ,coal ,degrees ,fahren- heit per ,barrel of ,oil ---------------------------------------- --------------------- #gc #ga #dedi #b4aihb4fchc4jggc4eafc4ieed4cied4hcee4bg e #gd #gb #dfac #b4afhb4fjac4jcec4dfhc4ijbd4cced4gfie4bj b #ge #gc #dfgg #b4achb4efeb4iicc4dbjc4hdhd4bged4gjce4ac a #gf #gd #dgda #b4aajb4ecbb4iedc4cgfc4gihd4bbjd4fdbe4jf c #gg #ge #dhjg #b4jhbb4dihb4iadc4ccjc4gdfd4afbd4eghd4ii d #gh #gf #dhfi #b4jedb4dfeb4hgfc4bhfc4figd4ajhd4eahd4ib i #gi #gg #dicb #b4jbgb4dccb4hchc4bdcc4fdid4jedd4dfjd4hf e #hj #gh #diif #b4jjbb4djbb4hjbc4bjbc4fjbd4jjcd4djcd4hj c #ha #gi #ejfj #a4igfb4cgab4gfgc4afbc4eegc4iebd4cdhd4gd c #hb #hj #eabd #a4iebb4cdbb4gcbc4abbc4eacc4ijcd4bicd4fh c #hc #ha #eahg #a4ibgb4cacb4fiic4jhec4dgjc4hefd4bdad4fb g ---------------------------------------- --------------------- ,illustration3 ,city of ,san ,francisco1 ,cal41 ,fire ,fighting ,station4 ,no4 #a4 #bhjj ,horse ,power of ,babcock ,wilcox ,boilers1 ,equipped for ,burning ,oil ,fuel ,many tables have been published with a view to comparing the two fuels4 ,such of these as are based solely on the relative calorific values of oil and coal are of limited value1 inasmuch as the efficiencies to be obtained with oil are higher than that obtainable with coal4 ,table #dg takes into consideration the variation in efficiency with the two fuels1 but is based on a constant calorific value for oil and coal4 ,this table1 like others of a similar nature1 while useful as a rough guide1 cannot be considered as an accurate basis for comparison4 ,this is due to the fact that there are numerous factors entering into the problem which affect the saving possible to a much greater extent than do the relative calorific values of two fuels4 ,some of the features to be considered in arriving at the true basis for comparison are the labor saving possible1 the space available for fuel storage1 the facilities for conveying the oil by pipe lines1 the hours during which a plant is in operation1 the load factor1 the quantity of coal required for banking fires1 etc41 etc4 ,the only exact method of estimating the relative advantages and costs of the two fuels is by considering the operating expenses of the plant with each in turn1 including the costs of every item entering into the problem4 ,burning ,oil ,fuel--,the requirements for burning petroleum are as follows3 #ast4 ,its atomization must be thorough4 #bnd4 ,when atomized it must be brought into contact with the requisite quantity of air for its combustion1 and this quantity must be at the same time a minimum to obviate loss in stack gases4 #crd4 ,the mixture must be burned in a furnace where a refractory material radiates heat to assist in the combustion1 and the furnace must stand up under the high temperatures developed4 #dth4 ,the combustion must be completed before the gases come into contact with the heating surfaces or otherwise the flame will be extinguished1 possibly to ignite later in the flue connection or in the stack4 #eth4 ,there must be no localization of the heat on certain portions of the heating surfaces or trouble will result from overheating and blistering4 ,the first requirement is met by the selection of a proper burner4 ,the second requirement is fulfilled by properly introducing the air into the furnace1 either through checkerwork under the burners or through openings around them1 and by controlling the quantity of air to meet variations in furnace conditions4 ,the third requirement is provided for by installing a furnace so designed as to give a sufficient area of heated brickwork to radiate the heat required to maintain a proper furnace temperature4 ,the fourth requirement is provided for by giving ample space for the combustion of the mixture of atomized oil and air1 and a gas travel of sufficient length to insure that this combustion be completed before the gases strike the heating surfaces4 ,the fifth requirement is fulfilled by the adoption of a suitable burner in connection with the furnace meeting the other requirements4 ,a burner must be used from which the flame will not impinge directly on the heating surface and must be located where such action cannot take place4 ,if suitable burners properly located are not used1 not only is the heat localized with disastrous results1 but the efficiency is lowered by the cooling of the gases before combustion is completed4 ,oil ,burners--,the functions of an oil burner is to atomize or vaporize the fuel so that it may be burned like a gas4 ,all burners may be classified under three general types3 #ast1 spray burners1 in which the oil is atomized by steam or compressed air2 #bnd1 vapor burners1 in which the oil is converted into vapor and then passed into the furnace2 #crd1 mechanical burners1 in which the oil is atomized by submitting it to a high pressure and passing it through a small orifice4 ,vapor burners have never been in general use and will not be discussed4 ,spray burners are almost universally used for land practice and the simplicity of the steam atomizer and the excellent economy of the better types1 together with the low oil pressure and temperature required makes this type a favorite for stationary plants1 where the loss of fresh water is not a vital consideration4 ,in marine work1 or in any case where it is advisable to save feed water that otherwise would have to be added in the form of make-up1 either compressed air or mechanical means are used for atomization4 ,spray burners using compressed air as the atomizing agent are in satisfactory operation in some plants1 but their use is not general4 ,where there is no necessity of saving raw feed water1 the greater simplicity and economy of the steam spray atomizer is generally the most satisfactory4 ,the air burners require blowers1 compressors or other apparatus which occupy space that might be otherwise utilized and require attention that is not necessary where steam is used4 ,steam spray burners of the older types had disadvantages in that they were so designed that there was a tendency for the nozzle to clog with sludge or coke formed from the oil by the heat1 without means of being readily cleaned4 ,this has been overcome in the more modern types4 ,steam spray burners1 as now used1 may be divided into two classes3 #ast1 inside mixers2 and #bnd1 outside mixers4 ,in the former the steam and oil come into contact within the burner and the mixture is atomized in passing through the orifice of the burner nozzle4 ,illustration3 ,fig4 #bh4 ,peabody ,oil ,burner ,in the outside mixing class the steam flows through a narrow slot or horizontal row of small holes in the burner nozzle2 the oil flows through a similar slot or hole above the steam orifice1 and is picked up by the steam outside of the burner and is atomized4 ,fig4 #bh shows a type of the ,peabody burner of this class1 which has given eminent satisfaction4 ,the construction is evident from the cut4 ,it will be noted that the portions of the burner forming the orifice may be readily replaced in case of wear1 or if it is desired to alter the form of the flame4 ,where burners of the spray type are used1 heating the oil is of advantage not only in causing it to be atomized more easily1 but in aiding economical combustion4 ,the temperature is1 of course1 limited by the flash point of the oil used1 but within the limit of this temperature there is no danger of decomposition or of carbon deposits on the supply pipes4 ,such heating should be done close to the boiler to minimize radiation loss4 ,if the temperature is raised to a point where an appreciable vaporization occurs1 the oil will flow irregularly from the burner and cause the flame to sputter4 ,on both steam and air atomizing types1 a by-pass should be installed between the steam or air and the oil pipes to provide for the blowing out of the oil duct4 ,strainers should be provided for removing sludge from the fuel and should be so located as to allow for rapid removal1 cleaning and replacing4 ,mechanical burners have been in use for some time in ,european countries1 but their introduction and use has been of only recent occurrence in the ,united ,states4 ,here as already stated1 the means for atomization are purely mechanical4 ,the most successful of the mechanical atomizers up to the present have been of the round flame type1 and only these will be considered4 ,experiments have been made with flat flame mechanical burners1 but their satisfactory action has been confined to instances where it is only necessary to burn a small quantity of oil through each individual burner4 ,this system of oil burning is especially adapted for marine work as the quantity of steam for putting pressure on the oil is small and the condensed steam may be returned to the system4 ,the only method by which successful mechanical atomization has been accomplished is one by which the oil is given a whirling motion within the burner tip4 ,this is done either by forcing the oil through a passage of helical form or by delivering it tangentially to a circular chamber from which there is a central outlet4 ,the oil is fed to these burners under a pressure which varies with the make of the burner and the rates at which individual burners are using oil4 ,the oil particles fly off from such a burner in straight lines in the form of a cone rather than in the form of a spiral spray1 as might be supposed4 ,with burners of the mechanical atomizing design1 the method of introducing air for combustion and the velocity of this air are of the greatest importance in securing good combustion and in the effects on the character and shape of the flame4 ,such burners are located at the front of the furnace and various methods have been tried for introducing the air for combustion4 ,where1 in the spray burners1 air is ordinarily admitted through a checkerwork under the burner proper1 with the mechanical burner1 it is almost universally admitted around the burner4 ,early experiments with these air distributors were confined largely to single or duplicate cones used with the idea of directing the air to the axis of the burner4 ,a highly successful method of such air introduction1 developed by ,messrs4 ,peabody and ,irish of ,the ,babcock ,wilcox ,co41 is by means of what they term an impeller plate4 ,this consists of a circular metal disk with an opening at the center for the oil burner and with radial metal strips from the center to the periphery turned at an angle which in the later designs may be altered to give the air supply demanded by the rate of combustion4 ,the air so admitted does not necessarily require a whirling motion1 but experiments show that where the air is brought into contact with the oil spray with the right twist1 better combustion is secured and lower air pressures and less refinement of adjustment of individual burners are required4 ,mechanical burners have a distinct advantage over those in which steam is used as the atomizing agent in that they lend themselves more readily to adjustment under wider variations of load4 ,for a given horse power there will ordinarily be installed a much greater number of mechanical than steam atomizing burners4 ,this in itself is a means to better regulation1 for with the steam atomizing burner1 if one of a number is shut off1 there is a marked decrease in efficiency4 ,this is due to the fact that with the air admitted under the burner1 it is ordinarily passing through the checkerwork regardless of whether it is being utilized for combustion or not4 ,with a mechanical burner1 on the other hand1 where individual burners are shut off1 air that would be admitted for such burner1 were it in operation1 may also be shut off and there will be no undue loss from excess air4 ,further adjustment to meet load conditions is possible by a change in the oil pressure acting on all burners at once4 ,a good burner will atomize moderately heavy oil with an oil pressure as low as #cj pounds per square inch and from that point up to #bjj pounds or above4 ,the heating of the oil also has an effect on the capacity of individual burners and in this way a third method of adjustment is given4 ,under working conditions1 the oil pressure remaining constant1 the capacity of each burner will decrease as the temperature of the oil is increased though at low temperatures the reverse is the case4 ,some experiments with a ,texas crude oil having a flash point of #baj degrees showed that the capacity of a mechanical atomizing burner of the ,peabody type increased from #hj degrees ,fahrenheit to #aaj degrees ,fahrenheit1 from which point it fell off rapidly to #adj degrees and then more slowly to the flash point4 ,the above methods1 together with the regulation possible through manipulation of the boiler dampers1 indicate the wide range of load conditions that may be handled with an installation of this class of burners4 ,as has already been stated1 results with mechanical atomizing burners that may be considered very successful have been limited almost entirely to cases where forced blast of some description has been used1 the high velocity of the air entering being of material assistance in securing the proper mixture of air with the oil spray4 ,much has been done and is being done in the way of experiment with this class of apparatus toward developing a successful mechanical atomizing burner for use with natural draft1 and there appears to be no reason why such experiments should not eventually produce satisfactory results4 ,steam ,consumption of ,burners--,the ,bureau of ,steam ,engineering1 ,u4 ,s4 ,navy1 made in #aija an exhaustive series of tests of various oil burners that may be considered as representing1 in so far as the performance of the burners themselves is concerned1 the practice of that time4 ,these tests showed that a burner utilizing air as an atomizing agent1 required for compressing the air from #a4jf to #g4de per cent of the total steam generated1 the average being #c4ah per cent4 ,four tests of steam atomizing burners showed a consumption of #c4ih to #e4gg per cent of the total steam1 the average being #d4h per cent4 ,improvement in burner design has largely reduced the steam consumption1 though to a greater degree in steam than in air atomizing burners4 ,recent experiments show that a good steam atomizing burner will require approximately #b per cent of the total steam generated by the boiler operated at or about its rated capacity4 ,this figure will decrease as the capacity is increased and is so low as to be practically negligible1 except in cases where the question of loss of feed water is all important4 ,there are no figures available as to the actual steam consumption of mechanical atomizing burners but apparently this is small if the requirement is understood to be entirely apart from the steam consumption of the apparatus producing the forced blast4 ,capacity of ,burners--,a good steam atomizing burner properly located in a well-designed oil furnace has a capacity of somewhat over #djj horse power4 ,this question of capacity of individual burners is largely one of the proper relation between the number of burners used and the furnace volume4 ,in some recent tests with a ,babcock ,wilcox boiler of #fdj rated horse power1 equipped with three burners1 approximately #acej horse power was developed with an available draft of 4#ee inch at the damper or #dej horse power per burner4 ,four burners were also tried in the same furnace but the total steam generated did not exceed #acej horse power or in this instance #cch horse power per burner4 ,from the nature of mechanical atomizing burners1 individual burners have not as large a capacity as the steam atomizing class4 ,in some tests on a ,babcock ,wilcox marine boiler1 equipped with mechanical atomizing burners1 the maximum horse power developed per burner was approximately #aje4 ,here again the burner capacity is largely one of proper relation between furnace volume and number of burners4 ,furnace ,design--,too much stress cannot be laid on the importance of furnace design for the use of this class of fuel4 ,provided a good type of burner is adopted the furnace arrangement and the method of introducing air for combustion into the furnace are the all important factors4 ,no matter what the type of burner1 satisfactory results cannot be secured in a furnace not suited to the fuel4 ,the ,babcock ,wilcox ,co4 has had much experience with the burning of oil as fuel and an extended series of experiments by ,mr4 ,e4 ,h4 ,peabody led to the development and adoption of the ,peabody furnace as being most eminently suited for this class of work4 ,fig4 #bi shows such a furnace applied to a ,babcock ,wilcox boiler1 and with slight modification it can be as readily applied to any boiler of ,the ,babcock ,wilcox ,co4 manufacture4 ,in the description of this furnace1 its points of advantage cover the requirements of oil-burning furnaces in general4 ,the atomized oil is introduced into the furnace in the direction in which it increases in height4 ,this increase in furnace volume in the direction of the flame insures free expansion and a thorough mixture of the oil with the air1 and the consequent complete combustion of the gases before they come into contact with the tube heating surfaces4 ,in such a furnace flat flame burners should be used1 preferably of the ,peabody type1 in which the flame spreads outward toward the sides in the form of a fan4 ,there is no tendency of the flames to impinge directly on the heating surfaces1 and the furnace can handle any quantity of flame without danger of tube difficulties4 ,the burners should be so located that the flames from individual burners do not interfere nor impinge to any extent on the side walls of the furnace1 an even distribution of heat being secured in this manner4 ,the burners are operated from the boiler front and peepholes are supplied through which the operator may watch the flame while regulating the burners4 ,the burners can be removed1 inspected1 or cleaned and replaced in a few minutes4 ,air is admitted through a checkerwork of fire brick supported on the furnace floor1 the openings in the checkerwork being so arranged as to give the best economic results in combustion4 ,illustration3 ,fig4 #bi4 ,babcock ,wilcox ,boiler1 ,equipped with a ,peabody ,oil ,furnace ,with steam atomizing burners introduced through the front of the boiler in stationary practice1 it is usually in the direction in which the furnace decreases in height and it is with such an arrangement that difficulties through the loss of tubes may be expected4 ,with such an arrangement1 the flame may impinge directly upon the tube surfaces and tube troubles from this source may arise1 particularly where the feed water has a tendency toward rapid scale formation4 ,such difficulties may be the result of a blowpipe action on the part of the burner1 the over heating of the tube due to oil or scale within1 or the actual erosion of the metal by particles of oil improperly atomized4 ,such action need not be anticipated1 provided the oil is burned with a short flame4 ,the flames from mechanical atomizing burners have a less velocity of projection than those from steam atomizing burners and if introduced into the higher end of the furnace1 should not lead to tube difficulties provided they are properly located and operated4 ,this class of burner also will give the most satisfactory results if introduced so that the flames travel in the direction of increase in furnace volume4 ,this is perhaps best exemplified by the very good results secured with mechanical atomizing burners and ,babcock ,wilcox marine boilers in which1 due to the fact that the boilers are fired from the low end1 the flames from burners introduced through the front are in this direction4 ,operation of ,burners--,when burners are not in use1 or when they are being started up1 care must be taken to prevent oil from flowing and collecting on the floor of the furnace before it is ignited4 ,in starting a burner1 the atomized fuel may be ignited by a burning wad of oil-soaked waste held before it on an iron rod4 ,to insure quick ignition1 the steam supply should be cut down4 ,but little practice is required to become an adept at lighting an oil fire4 ,when ignition has taken place and the furnace brought to an even heat1 the steam should be cut down to the minimum amount required for atomization4 ,this amount can be determined from the appearance of the flame4 ,if sufficient steam is not supplied1 particles of burning oil will drop to the furnace floor1 giving a scintillating appearance to the flame4 ,the steam valves should be opened just sufficiently to overcome this scintillating action4 ,air ,supply--,from the nature of the fuel and the method of burning1 the quantity of air for combustion may be minimized4 ,as with other fuels1 when the amount of air admitted is the minimum which will completely consume the oil1 the results are the best4 ,the excess or deficiency of air can be judged by the appearance of the stack or by observing the gases passing through the boiler settings4 ,a perfectly clear stack indicates excess air1 whereas smoke indicates a deficiency4 ,with properly designed furnaces the best results are secured by running near the smoking point with a slight haze in the gases4 ,a slight variation in the air supply will affect the furnace conditions in an oil burning boiler more than the same variation where coal is used1 and for this reason it is of the utmost importance that flue gas analysis be made frequently on oil-burning boilers4 ,with the air for combustion properly regulated by adjustment of any checkerwork or any other device which may be used1 and the dampers carefully set1 the flue gas analysis should show1 for good furnace conditions1 a percentage of ,,co#b between #ac and #ad per cent1 with either no ,,co or but a trace4 ,in boiler plant operation it is difficult to regulate the steam supply to the burners and the damper position to meet sudden and repeated variations in the load4 ,a device has been patented which automatically regulates by means of the boiler pressure the pressure of the steam to the burners1 the oil to the burners and the position of the boiler damper4 ,such a device has been shown to give good results in plant operation where hand regulation is difficult at best1 and in many instances is unfortunately not even attempted4 ,efficiency with ,oil--,as pointed out in enumerating the advantages of oil fuel over coal1 higher efficiencies are obtainable with the former4 ,with boilers of approximately #ejj horse power equipped with properly designed furnaces and burners1 an efficiency of #hc per cent is possible or making an allowance of #b per cent for steam used by burners1 a net efficiency of #ha per cent4 ,the conditions under which such efficiencies are to be secured are distinctly test conditions in which careful operation is a prime requisite4 ,with furnace conditions that are not conductive to the best combustion1 this figure may be decreased by from #e to #aj per cent4 ,in large properly designed plants1 however1 the first named efficiency may be approached for uniform running conditions1 the nearness to which it is reached depending on the intelligence of the operating crew4 ,it must be remembered that the use of oil fuel presents to the careless operator possibilities for wastefulness much greater than in plants where coal is fired1 and it therefore pays to go carefully into this feature4 ,table #dh gives some representative tests with oil fuel4 ,,table #dh ,,tests ,,of ,,babcock ,,and ,,wilcox ,,boilers ,,with ,,oil ,,fuel ,pacific ,light,pacific ,light,miami ,copper and ,power and ,power ,company ,plant ,company ,company ,los ,angeles1 ,miami1 ,cal4 ,redondo1 ,cal4 ,arizona ,rated ,capacity ,horse of ,boiler ,power #dfg #fjd #fjj ,duration of ,test ,hours #aj #aj #g #g #aj #d ,steam ,pressure by ,gauge ,pounds #aef4d #aef4i #ahd4g #ahd4i #ahc4d #ahi4e ,temperature of ,degrees ,feed ,water ,f4 #fb4f #fa4a #ic4d #aja4b #aeg4g #aef4f ,degrees of ,degrees ,superheat ,f4 #hc4g #add4c #ajc4d #aci4f ,factor of ,evaporation #a4bjjda4bjbja4bbbga4bdgea4afgfa4ahhf ,draft in ,furnace ,inches 4#jb 4#je 4#jad 4#ai 4#ab 4#bb ,draft at ,damper ,inches 4#jh 4#ae 4#jdf 4#dg 4#ai 4#fg ,temperature of ,degrees ,exit ,gases ,f4 #dch #ebe #djf #ecg #dcj #fab ,flue ,,co#b ,per ,cent #ad4c #ab4a ,gas ,o ,per ,cent #c4h #f4h ,analysis,,co ,per ,cent #j4j #j4j ,oil ,burned per ,hour ,pounds #aadg #ahcg #adci #bhfi #adjd #cbad ,water ,evaporated per ,hour from from and at ,pounds #ahcaj #bghee #bbfci #djcge #bagbj #dbhfc #bab ,degrees ,evaporation from and at #bab ,degrees per ,pounds #ae4if #ae4af #ae4gc #ad4jg #ae4dg #ac4cd ,pound of ,oil ,per ,cent of ,rated ,capacity ,pounds #aac4f #agb4i #ajh4f #aic4h #ajd4i #bjg4a ,developed ,b4 t4 u4 per ,pound of ,oil ,b4 t4 u4 #ahfbf #aheah #ahcbf #ahjif #ahfjj #ahfjj ,efficiency ,per ,cent #hc4ae #gi4df #hc4bi #gf4jb #hj4gj #fi4f ,burning ,oil in ,connection with ,other ,fuels--,considerable attention has been recently given to the burning of oil in connection with other fuels1 and a combination of this sort may be advisable either with the view to increasing the boiler capacity to assist over peak loads1 or to keep the boiler in operation where there is the possibility of a temporary failure of the primary fuel4 ,it would appear from experiments that such a combination gives satisfactory results from the standpoint of both capacity and efficiency1 if the two fuels are burned in separate furnaces4 ,satisfactory results cannot ordinarily be obtained when it is attempted to burn oil fuel in the same furnace as the primary fuel1 as it is practically impossible to admit the proper amount of air for combustion for each of the two fuels simultaneously4 ,the ,babcock ,wilcox boiler lends itself readily to a double furnace arrangement and ,fig4 #cj shows an installation where oil fuel is burned as an auxiliary to wood4 ,illustration3 ,fig4 #cj4 ,babcock ,wilcox ,boiler ,set with ,combination ,oil and ,wood-burning ,furnace ,water-gas ,tar--,water-gas tar1 or gas-house tar1 is a by-product of the coal used in the manufacture of water gas4 ,it is slightly heavier than crude oil and has a comparatively low flash point4 ,in burning1 it should be heated only to a temperature which makes it sufficiently fluid1 and any furnace suitable for crude oil is in general suitable for water-gas tar4 ,care should be taken where this fuel is used to install a suitable apparatus for straining it before it is fed to the burner4 ,illustration3 ,babcock ,wilcox ,boilers ,fired with ,blast ,furnace ,gas at the ,bethlehem ,steel ,co41 ,bethlehem1 ,pa4 ,this ,company ,operates #ab1ijj ,horse ,power of ,babcock ,wilcox ,boilers ,,gaseous ,,fuels ,,and ,,their ,,combustion ,of the gaseous fuels available for steam generating purposes1 the most common are blast furnace gas1 natural gas and by-product coke oven gas4 ,blast furnace gas1 as implied by its name1 is a by-product from the blast furnace of the iron industry4 ,this gasification of the solid fuel in a blast furnace results1 #ast1 through combustion by the oxygen of the blast2 #bnd1 through contact with the incandescent ore 7,fe#b,o#c ,c #b ,fe,o ,,co and ,fe,o ,c ,fe ,,co72 and #crd1 through the agency of ,,co#b either formed in the process of reduction or driven from the carbonates charged either as ore or flux4 ,approximately #ij per cent of the fuel consumed in all of the blast furnaces of the ,united ,states is coke4 ,the consumption of coke per ton of iron made varies from #afjj to #cfjj pounds per ton of #bbdj pounds of iron4 ,this consumption depends upon the quality of the coal1 the nature of the ore1 the quality of the pig iron produced and the equipment and management of the plant4 ,the average consumption1 and one which is approximately correct for ordinary conditions1 is #bjjj pounds of coke per gross ton 7#bbdj pounds7 of pig iron4 ,the gas produced in a gas furnace per ton of pig iron is obtained from the weight of fixed carbon gasified1 the weight of the oxygen combined with the material of charge reduced1 the weight of the gaseous constituents of the flux and the weight of air delivered by the blowing engine and the weight of volatile combustible contained in the coke4 ,ordinarily1 this weight of gas will be found to be approximately five times the weight of the coke burned1 or #aj1jjj pounds per ton of pig iron produced4 ,with the exception of the small amount of carbon in combination with hydrogen as methane1 and a very small percentage of free hydrogen1 ordinarily less than #j4a per cent1 the calorific value of blast furnace gas is due to the ,,co content which when united with sufficient oxygen when burned under a boiler1 burns further to ,,co#b4 ,the heat value of such gas will vary in most cases from #he to #ajj ,b4 t4 u4 per cubic foot under standard conditions4 ,in modern practice1 where the blast is heated by hot blast stoves1 approximately #ae per cent of the total amount of gas is used for this purpose1 leaving #he per cent of the total for use under boilers or in gas engines1 that is1 approximately #hejj pounds of gas per ton of pig iron produced4 ,in a modern blast furnace plant1 the gas serves ordinarily as the only fuel required4 ,table #di gives the analyses of several samples of blast furnace gas4 ,,table #di ,,typical ,,analyses ,,of ,,blast ,,furnace ,,gas ---------------------------------------- ------------------------ ---------------------------------------- ---------------- ,,co#b ,o ,,co ,h ,,ch#d ,n ---------------------------------------- ---------------- ,bessemer ,furnace #i4hej4cfcb4gcc4ad 44 #ec4ib ,bessemer ,furnace #aa4d 44 #bg4g #a4i #j4c #eh4g ,bessemer ,furnace #aj4j 44 #bf4b #c4a #j4b #fj4e ,bessemer ,furnace #i4a 44 #bh4g #b4g #j4b #ei4c ,bessemer ,furnace #ac4e 44 #be4b #a4dc 44 #ei4hg ,bessemer ,furnace#dg #aj4i 44 #bg4h #b4h #j4b #eh4c ,ferro ,manganese ,furnace #g4a 44 #cj4a 44 44 #fb4hdh ,basic ,ore ,furnace #af4j #j4b #bc4f 44 44 #fj4bdh ---------------------------------------- ---------------- ---------------------------------------- ------------------------ ,until recently1 the important consideration in the burning of blast furnace gas has been the capacity that can be developed with practically no attention given to the aspect of efficiency4 ,this phase of the question is now drawing attention and furnaces especially designed for good efficiency with this class of fuel are demanded4 ,the essential feature is ample combustion space1 in which the combustion of gases may be practically completed before striking the heating surfaces4 ,the gases have the power of burning out completely after striking the heating surfaces1 provided the initial temperature is sufficiently high1 but where the combustion is completed before such time1 the results secured are more satisfactory4 ,a furnace volume of approximately #a to #a4e cubic feet per rated boiler horse power will give a combustion space that is ample4 ,where there is the possibility of a failure of the gas supply1 or where steam is required when the blast furnace is shut down1 coal fired grates of sufficient size to get the required capacity should be installed4 ,where grates of full size are not required1 ignition grates should be installed1 which need be only large enough to carry a fire for igniting the gas or for generating a small quantity of steam when the blast furnace is shut down4 ,the area of such grates has no direct bearing on the size of the boiler4 ,the grates may be placed directly under the gas burners in a standard position or may be placed between two bridge walls back of the gas furnace and fired from the side of the boiler4 ,an advantage is claimed for the standard grate position that it minimizes the danger of explosion on the re-ignition of gas after a temporary stoppage of the supply and also that a considerable amount of dirt1 of which there is a good deal with this class of fuel and which is difficult to remove1 deposits on the fire and is taken out when the fires are cleaned4 ,in any event1 regardless of the location of the grates1 ample provision should be made for removing this dust1 not only from the furnace but from the setting as a whole4 ,blast furnace gas burners are of two general types3 ,those in which the air for combustion is admitted around the burner proper1 and those in which this air is admitted through the burner4 ,whatever the design of burner1 provision should be made for the regulation of both the air and the gas supply independently4 ,a gas opening of 4#h square inch per rated horse power will enable a boiler to develop its nominal rating with a gas pressure in the main of about #b inches4 ,this pressure is ordinarily from #f to #h inches and in this way openings of the above size will be good for ordinary overloads4 ,the air openings should be from 4#ge to 4#he square inch per rated horse power4 ,good results are secured by inclining the gas burners slightly downward toward the rear of the furnace4 ,where the burners are introduced over coal fired grates1 they should be set high enough to give headroom for hand firing4 ,ordinarily1 individual stacks of #acj feet high with diameters as given in ,kent's table for corresponding horse power are large enough for this class of work4 ,such a stack will give a draft sufficient to allow a boiler to be operated at #age per cent of its rated capacity1 and beyond this point the capacity will not increase proportionately with the draft4 ,when more than one boiler is connected with a stack1 the draft available at the damper should be equivalent to that which an individual stack of #acj feet high would give4 ,the draft from such a stack is necessary to maintain a suction under all conditions throughout all parts of the setting4 ,if the draft is increased above that which such a stack will give1 difficulties arise from excess air for combustion with consequent loss in efficiency4 ,a poor mixing or laneing action in the furnace may result in a pulsating effect of the gases in the setting4 ,this action may at times be remedied by admitting more air to the furnace4 ,on account of the possibility of a pulsating action of the gases under certain conditions and the puffs or explosions1 settings for this class of work should be carefully constructed and thoroughly buckstayed and tied4 ,natural ,gas--,natural gas from different localities varies considerably in composition and heating value4 ,in ,table #ej there is given a number of analyses and heat values for natural gas from various localities4 ,this fuel is used for steam generating purposes to a considerable extent in some localities1 though such use is apparently decreasing4 ,it is best burned by employing a large number of small burners1 each being capable of handling #cj nominal rated horse power4 ,the use of a large number of burners obviates the danger of any laneing or blowpipe action1 which might be present where large burners are used4 ,ordinarily1 such a gas1 as it enters the burners1 is under a pressure of about #h ounces4 ,for the purpose of comparison1 all observations should be based on gas reduced to the standard conditions of temperature and pressure1 namely #cb degrees ,fahrenheit and #ad4g pounds per square inch4 ,when the temperature and pressure corresponding to meter readings are known1 the volume of gas under standard conditions may be obtained by multiplying the meter readings in cubic feet by #cc4ed ,p_/,t1 in which ,p equals the absolute pressure in pounds per square inch and ,t equals the absolute temperature of the gas at the meter4 ,in boiler testing work1 the evaporation should always be reduced to that per cubic foot of gas under standard conditions4 ,,table #ej ,,typical ,,analyses 7,,by ,,volume7 ,,and ,,calorific ,,values ,,of ,,natural ,,gas ,,from ,,various ,,localities ---------------------------------------- -------------------------- ,locality of ,well ,h ,,ch#d ,,co ,,co#b ,n ,o ,heavy ,h#b,s,b4 t4 u4 ,hydro- per carbons ,cubic ,foot ,calcul- ated#di ---------------------------------------- -------------------------- ,anderson1 ,ind4 #a4hfic4jg #j4gc #j4bf #c4jbj4db #j4dg #j4ae #ajag ,marion1 ,ind4 #a4bjic4af #j4fj #j4cj #c4dcj4ee #j4ae #j4bj #ajji ,muncie1 ,ind4 #b4ceib4fg #j4de #j4be #c4ecj4ce #j4be #j4ae #ajjd ,olean1 ,n4 ,y4 #if4ej #j4ej #b4jj #a4jj #ajah ,findlay1 ,o4 #a4fdic4ce #j4da #j4be #c4daj4ci #j4ce #j4bj #ajaa ,st4 ,ive1 ,pa4 #f4ajge4ed,trace #j4cd #ah4ab #aaag ,cherry ,tree1 ,pa4#bb4ejfj4bg #b4bh #g4cbj4hc #f4hj #hdb ,grapeville1 ,pa4 #bd4efad4ic,trace,trace#ah4fia4bb #dj4fj #ibe ,harvey ,well1 ,butler ,co41 ,pa4#ac4ejhj4jj,trace #j4ff #e4gb #iih ,pittsburgh1 ,pa4 #i4fdeg4he #a4jj #bc4dab4aj #f4jj #gdh ,pittsburgh1 ,pa4 #bj4jbgb4ah #a4jj #j4hj #a4aj #d4cj #iag ,pittsburgh1 ,pa4 #bf4affe4be #j4hj #j4fj #j4hj #f4cj #hii ---------------------------------------- -------------------------- ,illustration3 #afjj ,horse-power ,installation of ,babcock ,wilcox ,boilers and ,superheaters at the ,carnegie ,natural ,gas ,co41 ,underwood1 ,w4 ,va4 ,natural ,gas is the ,fuel ,burned under these ,boilers ,when natural gas is the only fuel1 the burners should be evenly distributed over the lower portion of the boiler front4 ,if the fuel is used as an auxiliary to coal1 the burners may be placed through the fire front4 ,a large combustion space is essential and a volume of 4#ge cubic feet per rated horse power will be found to give good results4 ,the burners should be of a design which give the gas and air a rotary motion to insure a proper mixture4 ,a checkerwork wall is sometimes placed in the furnace about #c feet from the burners to break up the flame1 but with a good design of burner this is unnecessary4 ,where the gas is burned alone and no grates are furnished1 good results are secured by inclining the burner downward to the rear at a slight angle4 ,by-product ,coke ,oven ,gas--,by-product coke oven gas is a product of the destructive distillation of coal in a distilling or by-product coke oven4 ,in this class of apparatus the gases1 instead of being burned at the point of their origin1 as in a beehive or retort coke oven1 are taken from the oven through an uptake pipe1 cooled and yield as by-products tar1 ammonia1 illuminating and fuel gas4 ,a certain portion of the gas product is burned in the ovens and the remainder used or sold for illuminating or fuel purposes1 the methods of utilizing the gas varying with plant operation and locality4 ,table #ea gives the analyses and heat value of certain samples of by-product coke oven gas utilized for fuel purposes4 ,this gas is nearer to natural gas in its heat value than is blast furnace gas1 and in general the remarks as to the proper methods of burning natural gas and the features to be followed in furnace design hold as well for by-product coke oven gas4 ,,table #ea ,,typical ,,analyses ,,of ,,by-,,product ,,coke ,,oven ,,gas ---------------------------------------- ------ ---------------------------------------- --- ,,co#b ,o ,,co ,,ch#d ,h ,n ,b4t4u4 per ,cubic ,foot -------------------------------------- #j4ge ,trace#f4jbh4ae #ec4jab4a #eje #b4jj ,trace#c4bah4hj #eg4bah4j #cii #c4bj #j4d #f4cbi4fj #da4faf4a #eea #j4hj #a4f #d4ibh4dj #ed4baj4a #dfj -------------------------------------- ---------------------------------------- ------ ,the essential difference in burning the two fuels is the pressure under which it reaches the gas burner4 ,where this is ordinarily from #d to #h ounces in the case of natural gas1 it is approximately #d inches of water in the case of by-product coke oven gas4 ,this necessitates the use of larger gas openings in the burners for the latter class of fuel than for the former4 ,by-product coke oven gas comes to the burners saturated with moisture and provision should be made for the blowing out of water of condensation4 ,this gas too1 carries a large proportion of tar and hydrocarbons which form a deposit in the burners and provision should be made for cleaning this out4 ,this is best accomplished by an attachment which permits the blowing out of the burners by steam4 ,,utilization ,,of ,,waste ,,heat ,while it has been long recognized that the reclamation of heat from the waste gases of various industrial processes would lead to a great saving in fuel and labor1 the problem has1 until recently1 never been given the attention that its importance merits4 ,it is true that installations have been made for the utilization of such gases1 but in general they have consisted simply in the placing of a given amount of boiler heating surface in the path of the gases and those making the installations have been satisfied with whatever power has been generated1 no attention being given to the proportioning of either the heating surface or the gas passages to meet the peculiar characteristics of the particular class of waste gas available4 ,the ,babcock ,wilcox ,co4 has recently gone into the question of the utilization of what has been known as waste heat with great thoroughness1 and the results secured by their installations with practically all operations yielding such gases are eminently successful4 ,,table #eb ,,temperature ,,of ,,waste ,,gases ,,from ,,various ,,industrial ,,processes ---------------------------------------- ------------- ---------------------------------------- ---------- ,waste ,heat ,from ,temperature#ej ,degrees ---------------------------------------- ---------- ,brick ,kilns #bjjj-bcjj ,zinc ,furnaces #bjjj-bcjj ,copper ,matte ,reverberatory ,furnaces #bjjj-bbjj ,beehive ,coke ,ovens #ahjj-bjjj ,cement ,kilns #abjj-afjjea ,nickel ,refining ,furnaces #aejj-agej ,open ,hearth ,steel ,furnaces #aajj-adjj ---------------------------------------- ---------- ---------------------------------------- ------------- ,the power that can be obtained from waste gases depends upon their temperature and weight1 and both of these factors vary widely in different commercial operations4 ,table #eb gives a list of certain processes yielding waste gases the heat of which is available for the generation of steam and the approximate temperature of such gases4 ,it should be understood that the temperatures in the table are the average of the range of a complete cycle of the operation and that the minimum and maximum temperatures may vary largely from the figures given4 ,the maximum available horse power that may be secured from such gases is represented by the formula3 ,w7,t-t7s ,h4 ,p4 ------- 7#bc7 #cc1dgi ,where ,w the weight of gases passing per hour1 ,t temperature of gases entering heating surface1 t temperature leaving heating surface1 s specific heat of gases4 ,the initial temperature and the weight or volume of gas will depend1 as stated1 upon the process involved4 ,the exit temperature will depend1 to a certain extent1 upon the temperature of the entering gases1 but will be governed mainly by the efficiency of the heating surfaces installed for the absorption of the heat4 ,where the temperature of the gas available is high1 approaching that found in direct fired boiler practice1 the problem is simple and the question of design of boiler becomes one of adapting the proper amount of heating surface to the volume of gas to be handled4 ,with such temperatures1 and a volume of gas available approximately in accordance with that found in direct fired boiler practice1 a standard boiler or one but slightly modified from the standard will serve the purpose satisfactorily4 ,as the temperatures become lower1 however1 the problem is more difficult and the departure from standard practice more radical4 ,with low temperature gases1 to obtain a heat transfer rate at all comparable with that found in ordinary boiler practice1 the lack of temperature must be offset by an added velocity of the gases in their passage over the heating surfaces4 ,in securing the velocity necessary to give a heat transfer rate with low temperature gases sufficient to make the installation of waste heat boilers show a reasonable return on the investment1 the frictional resistance to the gases through the boiler becomes greatly in excess of what would be considered good practice in direct fired boilers4 ,practically all operations yielding waste gases require that nothing be done in the way of impairing the draft at the furnace outlet1 as this might interfere with the operation of the primary furnace4 ,the installation of a waste heat boiler1 therefore1 very frequently necessitates providing sufficient mechanical draft to overcome the frictional resistance of the gases through the heating surfaces and still leave ample draft available to meet the maximum requirements of the primary furnace4 ,where the temperature and volume of the gases are in line with what are found in ordinary direct fired practice1 the area of the gas passages may be practically standard4 ,with the volume of gas known1 the draft loss through the heating surfaces may be obtained from experimental data and this additional draft requirement met by the installation of a stack sufficient to take care of this draft loss and still leave draft enough for operating the furnace at its maximum capacity4 ,where the temperatures are low1 the added frictional resistance will ordinarily be too great to allow the draft required to be secured by additional stack height and the installation of a fan is necessary4 ,such a fan should be capable of handling the maximum volume of gas that the furnace may produce1 and of maintaining a suction equivalent to the maximum frictional resistance of such volume through the boiler plus the maximum draft requirement at the furnace outlet4 ,stacks and fans for this class of work should be figured on the safe side4 ,where a fan installation is necessary1 the loss of draft in the fan connections should be considered1 and in figuring conservatively it should be remembered that a fan of ample size may be run as economically as a smaller fan1 whereas the smaller fan1 if overloaded1 is operated with a large loss in efficiency4 ,in practically any installation where low temperature gas requires a fan to give the proper heat transfer from the gases1 the cost of the fan and of the energy to drive it will be more than offset by the added power from the boiler secured by its use4 ,furthermore1 the installation of such a fan will frequently increase the capacity of the industrial furnace1 in connection with which the waste heat boilers are installed4 ,in proportioning heating surfaces and gas passages for waste heat work there are so many factors bearing directly on what constitutes the proper installation that it is impossible to set any fixed rules4 ,each individual installation must be considered by itself as well as the particular characteristics of the gases available1 such as their temperature and volume1 and the presence of dust or tar-like substances1 and all must be given the proper weight in the determination of the design of the heating surfaces and gas passages for the specific set of conditions4 ,graph3 ,per ,cent of ,water ,heating ,surface passed over by ,gases_/,per ,cent of the ,total ,amount of ,steam ,generated in the ,boiler against ,temperature in ,degrees ,fahrenheit of ,hot ,gases ,sweeping ,heating ,surface ,fig4 #ca4 ,curve ,showing ,relation ,between ,gas ,temperature1 ,heating ,surface passed over1 and ,amount of ,steam ,generated4 ,ten ,square ,feet of ,heating ,surface are ,assumed as ,equivalent to ,one ,boiler ,horse ,power ,fig4 #ca shows the relation of gas temperatures1 heating surface passed over and work done by such surface for use in cases where the temperatures approach those found in direct fired practice and where the volume of gas available is approximately that with which one horse power may be developed on #aj square feet of heating surface4 ,the curve assumes what may be considered standard gas passage areas1 and further1 that there is no heat absorbed by direct radiation from the fire4 ,experiments have shown that this curve is very nearly correct for the conditions assumed4 ,such being the case1 its application in waste heat work is clear4 ,decreasing or increasing the velocity of the gases over the heating surfaces from what might be considered normal direct fired practice1 that is1 decreasing or increasing the frictional loss through the boiler will increase or decrease the amount of heating surface necessary to develop one boiler horse power4 ,the application of ,fig4 #ca to such use may best be seen by an example3 ,assume the entering gas temperatures to be #adgj degrees and that the gases are cooled to #egj degrees4 ,from the curve1 under what are assumed to be standard conditions1 the gases have passed over #ai per cent of the heating surface by the time they have been cooled #adgj degrees4 ,when cooled to #egj degrees1 #gh per cent of the heating surface has been passed over4 ,the work done in relation to the standard of the curve is represented by 7#adgj - #egj7 7#bejj - #ejj7 #de per cent4 7,these figures may also be read from the curve in terms of the per cent of the work done by different parts of the heating surfaces47 ,that is1 #gh per cent - #ai per cent #ei per cent of the standard heating surface has done #de per cent of the standard amount of work4 #ei #de #a4ca1 which is the ratio of surface of the assumed case to the standard case of the curve4 ,expressed differently1 there will be required #ac4a square feet of heating surface in the assumed case to develop a horse power as against #aj square feet in the standard case4 ,the gases available for this class of work are almost invariably very dirty4 ,it is essential for the successful operation of waste-heat boilers that ample provision be made for cleaning by the installation of access doors through which all parts of the setting may be reached4 ,in many instances1 such as waste-heat boilers set in connection with cement kilns1 settling chambers are provided for the dust before the gases reach the boiler4 ,by-passes for the gases should in all cases be provided to enable the boiler to be shut down for cleaning and repairs without interfering with the operation of the primary furnace4 ,all connections from furnace to boilers should be kept tight to prevent the infiltration of air1 with the consequent lowering of gas temperatures4 ,auxiliary gas or coal fired grates must be installed to insure continuity in the operation of the boiler where the operation of the furnace is intermittent or where it may be desired to run the boiler with the primary furnace not in operation4 ,such grates are sometimes used continuously where the gases available are not sufficient to develop the required horse power from a given amount of heating surface4 ,fear has at times been expressed that certain waste gases1 such as those containing sulphur fumes1 will have a deleterious action on the heating surface of the boiler4 ,this feature has been carefully watched1 however1 and from plants in operation it would appear that in the absence of water or steam leaks within the setting1 there is no such harmful action4 ,illustration3 ,fig4 #cb4 ,babcock ,wilcox ,boiler ,arranged for ,utilizing ,waste ,heat from ,open ,hearth ,furnace4 ,this ,setting may be ,modified to ,take ,care of ,practically any ,kind of ,waste ,gas ,,chimneys ,,and ,,draft ,the height and diameter of a properly designed chimney depend upon the amount of fuel to be burned1 its nature1 the design of the flue1 with its arrangement relative to the boiler or boilers1 and the altitude of the plant above sea level4 ,there are so many factors involved that as yet there has been produced no formula which is satisfactory in taking them all into consideration1 and the methods used for determining stack sizes are largely empirical4 ,in this chapter a method sufficiently comprehensive and accurate to cover all practical cases will be developed and illustrated4 ,draft is the difference in pressure available for producing a flow of the gases4 ,if the gases within a stack be heated1 each cubic foot will expand1 and the weight of the expanded gas per cubic foot will be less than that of a cubic foot of the cold air outside the chimney4 ,therefore1 the unit pressure at the stack base due to the weight of the column of heated gas will be less than that due to a column of cold air4 ,this difference in pressure1 like the difference in head of water1 will cause a flow of the gases into the base of the stack4 ,in its passage to the stack the cold air must pass through the furnace or furnaces of the boilers connected to it1 and it in turn becomes heated4 ,this newly heated gas will also rise in the stack and the action will be continuous4 ,the intensity of the draft1 or difference in pressure1 is usually measured in inches of water4 ,assuming an atmospheric temperature of #fb degrees ,fahrenheit and the temperature of the gases in the chimney as #ejj degrees ,fahrenheit1 and1 neglecting for the moment the difference in density between the chimney gases and the air1 the difference between the weights of the external air and the internal flue gases per cubic foot is 4#jcdg pound1 obtained as follows3 ,weight of a cubic foot of air at #fb degrees ,fahrenheit 4#jgfa pound ,weight of a cubic foot of air at #ejj degrees ,fahrenheit 4#jdad pound ------------------------ ,difference 4#jcdg pound ,therefore1 a chimney #ajj feet high1 assumed for the purpose of illustration to be suspended in the air1 would have a pressure exerted on each square foot of its cross sectional area at its base of 4#jcdg #ajj #c4dg pounds4 ,as a cubic foot of water at #fb degrees ,fahrenheit weighs #fb4cb pounds1 an inch of water would exert a pressure of #fb4cb #ab #e4aic pounds per square foot4 ,the #ajj-;foot stack would1 therefore1 under the above temperature conditions1 show a draft of #c4dg #e4aic or approximately #j4fg inches of water4 ,the method best suited for determining the proper proportion of stacks and flues is dependent upon the principle that if the cross sectional area of the stack is sufficiently large for the volume of gases to be handled1 the intensity of the draft will depend directly upon the height2 therefore1 the method of procedure is as follows3 #ast4 ,select a stack of such height as will produce the draft required by the particular character of the fuel and the amount to be burned per square foot of grate surface4 #bnd4 ,determine the cross sectional area necessary to handle the gases without undue frictional losses4 ,the application of these rules follows3 ,draft ,formula--,the force or intensity of the draft1 not allowing for the difference in the density of the air and of the flue gases1 is given by the formula3 _/ #a #a ,d #j4eb ,h ,p --- - ----- 7#bd7 ,t ,t#a_/ in which ,d draft produced1 measured in inches of water1 ,h height of top of stack above grate bars in feet1 ,p atmospheric pressure in pounds per square inch1 ,t absolute atmospheric temperature1 ,t#a absolute temperature of stack gases4 ,in this formula no account is taken of the density of the flue gases1 it being assumed that it is the same as that of air4 ,any error arising from this assumption is negligible in practice as a factor of correction is applied in using the formula to cover the difference between the theoretical figures and those corresponding to actual operating conditions4 ,the force of draft at sea level 7which corresponds to an atmospheric pressure of #ad4g pounds per square inch7 produced by a chimney #ajj feet high with the temperature of the air at #fj degrees ,fahrenheit and that of the flue gases at #ejj degrees ,fahrenheit is1 _/ #a #a ,d #j4eb #ajj #ad4g --- - --- #j4fg #eba #ifa _/ ,under the same temperature conditions this chimney at an atmospheric pressure of #aj pounds per square inch 7which corresponds to an altitude of about #aj1jjj feet above sea level7 would produce a draft of1 _/ #a #a ,d #j4eb #ajj #aj --- - --- #j4de #eba #ifa _/ ,for use in applying this formula it is convenient to tabulate values of the product _/ #a #a #j4eb #ad4g--- - ----- ,t ,t#a_/ which we will call ,k1 for various values of ,t#a4 ,with these values calculated for assumed atmospheric temperature and pressure 7#bd7 becomes ,d ,,kh4 7#be7 ,for average conditions the atmospheric pressure may be considered #ad4g pounds per square inch1 and the temperature #fj degrees ,fahrenheit4 ,for these values and various stack temperatures ,k becomes3 ,temperature ,stack ,gases ,constant ,k #gej 4#jjhd #gjj 4#jjha #fej 4#jjgh #fjj 4#jjge #eej 4#jjga #ejj 4#jjfg #dej 4#jjfc #djj 4#jjeh #cej 4#jjec ,draft ,losses--,the intensity of the draft as determined by the above formula is theoretical and can never be observed with a draft gauge or any recording device4 ,however1 if the ashpit doors of the boiler are closed and there is no perceptible leakage of air through the boiler setting or flue1 the draft measured at the stack base will be approximately the same as the theoretical draft4 ,the difference existing at other times represents the pressure necessary to force the gases through the stack against their own inertia and the friction against the sides4 ,this difference will increase with the velocity of the gases4 ,with the ashpit doors closed the volume of gases passing to the stack are a minimum and the maximum force of draft will be shown by a gauge4 ,as draft measurements are taken along the path of the gases1 the readings grow less as the points at which they are taken are farther from the stack1 until in the boiler ashpit1 with the ashpit doors open for freely admitting the air1 there is little or no perceptible rise in the water of the gauge4 ,the breeching1 the boiler damper1 the baffles and the tubes1 and the coal on the grates all retard the passage of the gases1 and the draft from the chimney is required to overcome the resistance offered by the various factors4 ,the draft at the rear of the boiler setting where connection is made to the stack or flue may be #j4e inch1 while in the furnace directly over the fire it may not be over1 say1 #j4ae inch1 the difference being the draft required to overcome the resistance offered in forcing the gases through the tubes and around the baffling4 ,one of the most important factors to be considered in designing a stack is the pressure required to force the air for combustion through the bed of fuel on the grates4 ,this pressure will vary with the nature of the fuel used1 and in many instances will be a large percentage of the total draft4 ,in the case of natural draft1 its measure is found directly by noting the draft in the furnace1 for with properly designed ashpit doors it is evident that the pressure under the grates will not differ sensibly from atmospheric pressure4 ,loss in ,stack--,the difference between the theoretical draft as determined by formula 7#bd7 and the amount lost by friction in the stack proper is the available draft1 or that which the draft gauge indicates when connected to the base of the stack4 ,the sum of the losses of draft in the flue1 boiler and furnace must be equivalent to the available draft1 and as these quantities can be determined from record of experiments1 the problem of designing a stack becomes one of proportioning it to produce a certain available draft4 ,the loss in the stack due to friction of the gases can be calculated from the following formula3 f ,w ,c ,h ,delta,d -------- 7#bf7 ,a in which ,delta,d draft loss in inches of water1 ,w weight of gas in pounds passing per second1 ,c perimeter of stack in feet1 ,h height of stack in feet1 f a constant with the following values at sea level3 4#jjae for steel stacks1 temperature of gases #fjj degrees ,fahrenheit4 4#jjaa for steel stacks1 temperature of gases #cej degrees ,fahrenheit4 4#jjbj for brick or brick-lined stacks1 temperature of gases #fjj degrees ,fahrenheit4 4#jjae for brick or brick-lined stacks1 temperature of gases #cej degrees ,fahrenheit4 ,a ,area of stack in square feet4 ,illustration3 #bd1dbj ,horse-power ,installation of ,babcock ,wilcox ,boilers and ,superheaters1 ,equipped with ,babcock ,wilcox ,chain ,grate ,stokers in the ,quarry ,street ,station of the ,commonwealth ,edison ,co41 ,chicago1 ,ill4 ,this formula can also be used for calculating the frictional losses for flues1 in which case1 ,c the perimeter of the flue in feet1 ,h the length of the flue in feet1 the other values being the same as for stacks4 ,the available draft is equal to the difference between the theoretical draft from formula 7#be7 and the loss from formula 7#bf71 hence3 f ,w ,c ,h d#a available draft ,,kh - -------- 7#bg7 ,a ,table #ec gives the available draft in inches that a stack #ajj feet high will produce when serving different horse powers of boilers with the methods of calculation for other heights4 ,,table #ec ,,available ,,draft ,,calculated ,,for #ajj-;,,foot ,,stack ,,of ,,different ,,diameters ,,assuming ,,stack ,,temperature ,,of #ejj ,,degrees ,,fahrenheit ,,and #ajj ,,pounds ,,of ,,gas ,,per ,,horse ,,power ,,for ,,other ,,heights ,,of ,,stack ,,multiply ,,draft ,,by ,,height #ajj ---------------------------------------- -------------------------------- ,horse ,power ,diameter of ,stack in ,inches ---------------------------------------- ---------------- #cf #db #dh #ed #fj #ff #gb #gh #hd #ij #if #ajbajhaadabjacbadd ---------------------------------------- ---------------- #ajj 4#fd #bjj 4#ee4fb #cjj 4#da4ee4fa #djj 4#ba4df4ef4fa #ejj 4#cd4ej4eg4fa #fjj 4#ai4db4ec4ei #gjj 4#cd4dh4ef4fj4fc #hjj 4#bc4dc4eb4eh4fa4fc #ijj 4#cf4di4ef4fj4fb4fd #ajjj 4#bi4de4ec4eh4fa4fc4fd #aajj 4#dj4ej4ef4fj4fb4fc4fd #abjj 4#ce4dg4ed4eh4fa4fc4fd4fe #acjj 4#bi4dd4eb4eg4fj4fb4fc4fd4fe #adjj 4#dj4di4ee4ei4fa4fc4fd4fe4fe #aejj 4#cf4dg4ec4eh4fj4fb4fc4fd4fe4fe #afjj 4#ca4dc4eb4ef4ei4fb4fc4fd4fe4fe #agjj 4#da4ej4ee4eh4fa4fb4fd4fd4fe #ahjj 4#cg4dg4ed4eg4fj4fb4fc4fd4fe #aijj 4#cd4de4eb4ef4ei4fa4fc4fd4fd #bjjj 4#dc4ej4ee4ei4fa4fb4fc4fd #bajj 4#dj4di4ed4eh4fj4fb4fc4fd #bbjj 4#ch4dg4ec4eg4ei4fa4fb4fd #bcjj 4#ce4de4eb4ef4ei4fa4fb4fc #bdjj 4#cb4dc4ej4ee4eh4fj4fb4fc #bejj 4#da4di4ed4eg4fj4fa4fc #bfjj 4#dg4ec4ef4ei4fa4fb4fd4fe #bgjj 4#de4eb4ee4eh4fj4fb4fd4fe #bhjj 4#dd4ei4ee4eh4fj4fa4fd4fe #bijj 4#db4di4ed4eg4ei4fa4fc4fe #cjjj 4#dj4dh4ec4ef4ei4fa4fc4fd #cajj 4#ch4dg4eb4ef4eh4fj4fc4fd #cbjj 4#de4ea4ee4eh4fj4fc4fd #ccjj 4#dd4ej4ed4eg4ei4fb4fd #cdjj 4#db4di4ec4ef4ei4fb4fd #cejj 4#dj4dh4eb4ef4eh4fb4fd #cfjj 4#dg4eb4ee4eh4fa4fc #cgjj 4#de4ea4ee4eg4fa4fc #chjj 4#dd4ej4ed4eg4fa4fc #cijj 4#dc4di4ec4ef4fj4fc #djjj 4#db4dh4eb4ef4fj4fb #dajj 4#dj4dg4eb4ee4fj4fb #dbjj 4#ci4df4ea4ee4ei4fb #dcjj 4#de4ej4ed4ei4fb #ddjj 4#dd4di4ec4ei4fb #dejj 4#dc4di4ec4eh4fa #dfjj 4#db4dh4eb4eh4fa #dgjj 4#da4dg4ea4eg4fa #dhjj 4#dj4df4ea4eg4fj #dijj 4#de4ej4eg4fj #ejjj 4#dd4di4ef4fj ---------------------------------------- ---------------- ,,for ,,other ,,stack ,,temperatures ,,add ,,or ,,deduct ,,before ,,multiplying ,,by ,,height #ajj ,,as ,,follows#eb ,for #gej ,degrees ,f4 ,add 4#ag inch4 ,for #gjj ,degrees ,f4 ,add 4#ad inch4 ,for #fej ,degrees ,f4 ,add 4#aa inch4 ,for #fjj ,degrees ,f4 ,add 4#jh inch4 ,for #eej ,degrees ,f4 ,add 4#jd inch4 ,for #dej ,degrees ,f4 ,deduct 4#jd inch4 ,for #djj ,degrees ,f4 ,deduct 4#ji inch4 ,for #cej ,degrees ,f4 ,deduct 4#ad inch4 ,graph3 ,horse ,power of ,boilers against ,diameter of ,stack in ,inches ,fig4 #cc4 ,diameter of ,stacks and ,horse ,power they will ,serve ,computed from ,formula 7#bh74 ,for brick or brick-lined stacks1 increase the diameter #f per cent ,height and ,diameter of ,stacks--,from this formula 7#bg7 it becomes evident that a stack of certain diameter1 if it be increased in height1 will produce the same available draft as one of larger diameter1 the additional height being required to overcome the added frictional loss4 ,it follows that among the various stacks that would meet the requirements of a particular case there must be one which can be constructed more cheaply than the others4 ,it has been determined from the relation of the cost of stacks to their diameters and heights1 in connection with the formula for available draft1 that the minimum cost stack has a diameter dependent solely upon the horse power of the boilers it serves1 and a height proportional to the available draft required4 ,assuming #abj pounds of flue gas per hour for each boiler horse power1 which provides for ordinary overloads and the use of poor coal1 the method above stated gives3 ,for an unlined steel stack-- diameter in inches #d4fh 7,h4 ,p47#b_/e 7#bh7 ,for a stack lined with masonry-- diameter in inches #d4ib 7,h4 ,p47#b_/e 7#bi7 ,in both of these formulae ,h4 ,p4 the rated horse power of the boiler4 ,from this formula the curve1 ,fig4 #cc1 has been calculated and from it the stack diameter for any boiler horse power can be selected4 ,for stoker practice where a large stack serves a number of boilers1 the area is usually made about one-third more than the above rules call for1 which allows for leakage of air through the setting of any idle boilers1 irregularities in operating conditions1 etc4 ,stacks with diameters determined as above will give an available draft which bears a constant ratio of the theoretical draft1 and allowing for the cooling of the gases in their passage upward through the stack1 this ratio is #h4 ,using this factor in formula 7#be71 and transposing1 the height of the chimney becomes1 d#a ,h ----- 7#cj7 4#h ,k ,where ,h height of stack in feet above the level of the grates1 d#a available draft required1 ,k constant as in formula4 ,losses in ,flues--,the loss of draft in straight flues due to friction and inertia can be calculated approximately from formula 7#bf71 which was given for loss in stacks4 ,it is to be borne in mind that ,c in this formula is the actual perimeter of the flue and is least1 relative to the cross sectional area1 when the section is a circle1 is greater for a square section1 and greatest for a rectangular section4 ,the retarding effect of a square flue is #ab per cent greater than that of a circular flue of the same area and that of a rectangular with sides as #a and #a1 #ae per cent greater4 ,the greater resistance of the more or less uneven brick or concrete flue is provided for in the value of the constants given for formula 7#bf74 ,both steel and brick flues should be short and should have as near a circular or square cross section as possible4 ,abrupt turns are to be avoided1 but as long easy sweeps require valuable space1 it is often desirable to increase the height of the stack rather than to take up added space in the boiler room4 ,short right-angle turns reduce the draft by an amount which can be roughly approximated as equal to #j4je inch for each turn4 ,the turns which the gases make in leaving the damper box of a boiler1 in entering a horizontal flue and in turning up into a stack should always be considered4 ,the cross sectional areas of the passages leading from the boilers to the stack should be of ample size to provide against undue frictional loss4 ,it is poor economy to restrict the size of the flue and thus make additional stack height necessary to overcome the added friction4 ,the general practice is to make flue areas the same or slightly larger than that of the stack2 these should be1 preferably1 at least #bj per cent greater1 and a safe rule to follow in figuring flue areas is to allow #ce square feet per #ajjj horse power4 ,it is unnecessary to maintain the same size of flue the entire distance behind a row of boilers1 and the areas at any point may be made proportional to the volume of gases that will pass that point4 ,that is1 the areas may be reduced as connections to various boilers are passed4 ,illustration3 #fjjj ,horse-power ,installation of ,babcock ,wilcox ,boilers at the ,united ,states ,navy ,yard1 ,washington1 ,d4 ,c4 ,with circular steel flues of approximately the same size as the stacks1 or reduced proportionally to the volume of gases they will handle1 a convenient rule is to allow #j4a inch draft loss per #ajj feet of flue length and #j4je inch for each right-angle turn4 ,these figures are also good for square or rectangular steel flues with areas sufficiently large to provide against excessive frictional loss4 ,for losses in brick or concrete flues1 these figures should be doubled4 ,underground flues are less desirable than overhead or rear flues for the reason that in most instances the gases will have to make more turns where underground flues are used and because the cross sectional area of such flues will oftentimes be decreased on account of an accumulation of dirt or water which it may be impossible to remove4 ,in tall buildings1 such as office buildings1 it is frequently necessary in order to carry spent gases above the roofs1 to install a stack the height of which is out of all proportion to the requirements of the boilers4 ,in such cases it is permissible to decrease the diameter of a stack1 but care must be taken that this decrease is not sufficient to cause a frictional loss in the stack as great as the added draft intensity due to the increase in height1 which local conditions make necessary4 ,in such cases also the fact that the stack diameter is permissibly decreased is no reason why flue sizes connecting to the stack should be decreased4 ,these should still be figured in proportion to the area of the stack that would be furnished under ordinary conditions or with an allowance of #ce square feet per #ajjj horse power1 even though the cross sectional area appears out of proportion to the stack area4 ,loss in ,boiler--,in calculating the available draft of a chimney #abj pounds per hour has been used as the weight of the gases per boiler horse power4 ,this covers an overload of the boiler to an extent of #ej per cent and provides for the use of poor coal4 ,the loss in draft through a boiler proper will depend upon its type and baffling and will increase with the per cent of rating at which it is run4 ,no figures can be given which will cover all conditions1 but for approximate use in figuring the available draft necessary it may be assumed that the loss through a boiler will be #j4be inch where the boiler is run at rating1 #j4dj inch where it is run at #aej per cent of its rated capacity1 and #j4gj inch where it is run at #bjj per cent of its rated capacity4 ,loss in ,furnace--,the draft loss in the furnace or through the fuel bed varies between wide limits4 ,the air necessary for combustion must pass through the interstices of the coal on the grate4 ,where these are large1 as is the case with broken coal1 but little pressure is required to force the air through the bed2 but if they are small1 as with bituminous slack or small sizes of anthracite1 a much greater pressure is needed4 ,if the draft is insufficient the coal will accumulate on the grates and a dead smoky fire will result with the accompanying poor combustion2 if the draft is too great1 the coal may be rapidly consumed on certain portions of the grate1 leaving the fire thin in spots and a portion of the grates uncovered with the resulting losses due to an excessive amount of air4 ,graph3 ,force of ,draft between ,furnace and ,ash ,pit--,inches of ,water against ,pounds of ,coal burned per ,square ,foot of ,grate ,surface per ,hour ,fig4 #cd4 ,draft ,required at ,different ,combustion ,rates for ,various ,kinds of ,coal ,draft ,required for ,different ,fuels--,for every kind of fuel and rate of combustion there is a certain draft with which the best general results are obtained4 ,a comparatively light draft is best with the free burning bituminous coals and the amount to use increases as the percentage of volatile matter diminishes and the fixed carbon increases1 being highest for the small sizes of anthracites4 ,numerous other factors such as the thickness of fires1 the percentage of ash and the air spaces in the grates bear directly on this question of the draft best suited to a given combustion rate4 ,the effect of these factors can only be found by experiment4 ,it is almost impossible to show by one set of curves the furnace draft required at various rates of combustion for all of the different conditions of fuel1 etc41 that may be met4 ,the curves in ,fig4 #cd1 however1 give the furnace draft necessary to burn various kinds of coal at the combustion rates indicated by the abscissae1 for a general set of conditions4 ,these curves have been plotted from the records of numerous tests and allow a safe margin for economically burning coals of the kinds noted4 ,rate of ,combustion--,the amount of coal which can be burned per hour per square foot of grate surface is governed by the character of the coal and the draft available4 ,when the boiler and grate are properly proportioned1 the efficiency will be practically the same1 within reasonable limits1 for different rates of combustion4 ,the area of the grate1 and the ratio of this area to the boiler heating surface will depend upon the nature of the fuel to be burned1 and the stack should be so designed as to give a draft sufficient to burn the maximum amount of fuel per square foot of grate surface corresponding to the maximum evaporative requirements of the boiler4 ,solution of a ,problem--,the stack diameter can be determined from the curve1 ,fig4 #cc4 ,the height can be determined by adding the draft losses in the furnace1 through the boiler and flues1 and computing from formula 7#cj7 the height necessary to give this draft4 ,example3 ,proportion a stack for boilers rated at #bjjj horse power1 equipped with stokers1 and burning bituminous coal that will evaporate #h pounds of water from and at #bab degrees ,fahrenheit per pound of fuel2 the ratio of boiler heating surface to grate surface being #ej3a2 the flues being #ajj feet long and containing two right-angle turns2 the stack to be able to handle overloads of #ej per cent2 and the rated horse power of the boilers based on #aj square feet of heating surface per horse power4 ,the atmospheric temperature may be assumed as #fj degrees ,fahrenheit and the flue temperatures at the maximum overload as #eej degrees ,fahrenheit4 ,the grate surface equals #djj square feet4 #bjjj #cd ,the total coal burned at rating ---------- #hfbd pounds4 #h ,the coal per square foot of grate surface per hour at rating #hfbd ---- #bb pounds4 #djj ,for #ej per cent overload the combustion rate will be approximately #fj per cent greater than this or #a4fj #bb #ce pounds per square foot of grate surface per hour4 ,the furnace draft required for the combustion rate1 from the curve1 ,fig4 #cd1 is #j4f inch4 ,the loss in the boiler will be #j4d inch1 in the flue #j4a inch1 and in the turns #b #j4je #j4a inch4 ,the available draft required at the base of the stack is1 therefore1 ,inches ,boiler #j4d ,furnace #j4f ,flues #j4a ,turns #j4a --- ,total #a4b ,since the available draft is #hj per cent of the theoretical draft1 this draft due to the height required is #a4b 4#h #a4e inch4 ,the chimney constant for temperatures of #fj degrees ,fahrenheit and #eej degrees ,fahrenheit is 4#jjga and from formula 7#cj71 #a4e ,h ----- #baa feet4 4#jjga ,its diameter from curve in ,fig4 #cc is #if inches if unlined1 and #ajb inches inside if lined with masonry4 ,the cross sectional area of the flue should be approximately #gj square feet at the point where the total amount of gas is to be handled1 tapering to the boiler farthest from the stack to a size which will depend upon the size of the boiler units used4 ,correction in ,stack ,sizes for ,altitudes--,it has ordinarily been assumed that a stack height for altitude will be increased inversely as the ratio of the barometric pressure at the altitude to that at sea level1 and that the stack diameter will increase inversely as the two-fifths power of this ratio4 ,such a relation has been based on the assumption of constant draft measured in inches of water at the base of the stack for a given rate of operation of the boilers1 regardless of altitude4 ,if the assumption be made that boilers1 flues and furnace remain the same1 and further that the increased velocity of a given weight of air passing through the furnace at a higher altitude would have no effect on the combustion1 the theory has been advanced#ec that a different law applies4 ,under the above assumptions1 whenever a stack is working at its maximum capacity at any altitude1 the entire draft is utilized in overcoming the various resistances1 each of which is proportional to the square of the velocity of the gases4 ,since boiler areas are fixed1 all velocities may be related to a common velocity1 say1 that within the stack1 and all resistances may1 therefore1 be expressed as proportional to the square of the chimney velocity4 ,the total resistance to flow1 in terms of velocity head1 may be expressed in terms of weight of a column of external air1 the numerical value of such head being independent of the barometric pressure4 ,likewise the draft of a stack1 expressed in height of column of external air1 will be numerically independent of the barometric pressure4 ,it is evident1 therefore1 that if a given boiler plant1 with its stack operated with a fixed fuel1 be transplanted from sea level to an altitude1 assuming the temperatures remain constant1 the total draft head measured in height of column of external air will be numerically constant4 ,the velocity of chimney gases will1 therefore1 remain the same at altitude as at sea level and the weight of gases flowing per second with a fixed velocity will be proportional to the atmospheric density or inversely proportional to the normal barometric pressure4 ,to develop a given horse power requires a constant weight of chimney gas and air for combustion4 ,hence1 as the altitude is increased1 the density is decreased and1 for the assumptions given above1 the velocity through the furnace1 the boiler passes1 breeching and flues must be correspondingly greater at altitude than at sea level4 ,the mean velocity1 therefore1 for a given boiler horse power and constant weight of gases will be inversely proportional to the barometric pressure and the velocity head measured in column of external air will be inversely proportional to the square of the barometric pressure4 ,for stacks operating at altitude it is necessary not only to increase the height but also the diameter1 as there is an added resistance within the stack due to the added friction from the additional height4 ,this frictional loss can be compensated by a suitable increase in the diameter and when so compensated1 it is evident that on the assumptions as given1 the chimney height would have to be increased at a ratio inversely proportional to the square of the normal barometric pressure4 ,in designing a boiler for high altitudes1 as already stated1 the assumption is usually made that a given grade of fuel will require the same draft measured in inches of water at the boiler damper as at sea level1 and this leads to making the stack height inversely as the barometric pressures1 instead of inversely as the square of the barometric pressures4 ,the correct height1 no doubt1 falls somewhere between the two values as larger flues are usually used at the higher altitudes1 whereas to obtain the ratio of the squares1 the flues must be the same size in each case1 and again the effect of an increased velocity of a given weight of air through the fire at a high altitude1 on the combustion1 must be neglected4 ,in making capacity tests with coal fuel1 no difference has been noted in the rates of combustion for a given draft suction measured by a water column at high and low altitudes1 and this would make it appear that the correct height to use is more nearly that obtained by the inverse ratio of the barometric readings than by the inverse ratio of the squares of the barometric readings4 ,if the assumption is made that the value falls midway between the two formulae1 the error in using a stack figured in the ordinary way by making the height inversely proportional to the barometric readings would differ about #aj per cent in capacity at an altitude of #aj1jjj feet1 which difference is well within the probable variation of the size determined by different methods4 ,it would1 therefore1 appear that ample accuracy is obtained in all cases by simply making the height inversely proportional to the barometric readings and increasing the diameter so that the stacks used at high altitudes have the same frictional resistance as those used at low altitudes1 although1 if desired1 the stack may be made somewhat higher at high altitudes than this rule calls for in order to be on the safe side4 ,the increase of stack diameter necessary to maintain the same friction loss is inversely as the two-fifths power of the barometric pressure4 ,table #ed gives the ratio of barometric readings of various altitudes to sea level1 values for the square of this ratio and values of the two-fifths power of this ratio4 ,,table #ed ,,stack ,,capacities1 ,,correction ,,factors ,,for ,,altitudes ,altitude ,r ,r#b_/e ,height in ,feet ,normal ,ratio ,barometer ,ratio ,increase ,above ,barometer ,reading ,r in ,stack ,sea ,level ,sea ,level to ,diameter ,altitude #j #cj4jj #a4jjj #a4jjj #a4jjj #ajjj #bh4hh #a4jci #a4jgi #a4jae #bjjj #bg4hj #a4jgi #a4jfd #a4jcj #cjjj #bf4gf #a4aba #a4beg #a4jdg #djjj #be4gf #a4afe #a4cef #a4jfc #ejjj #bd4gi #a4baj #a4dfd #a4jgi #fjjj #bc4hg #a4beg #a4ehj #a4jif #gjjj #bb4ig #a4cjf #a4gjf #a4aac #hjjj #bb4aa #a4ceg #a4hda #a4acj #ijjj #ba4bh #a4daj #a4ihh #a4adg #ajjjj #bj4di #a4dfd #b4add #a4afe ,these figures show that the altitude affects the height to a much greater extent than the diameter and that practically no increase in diameter is necessary for altitudes up to #cjjj feet4 ,for high altitudes the increase in stack height necessary is1 in some cases1 such as to make the proportion of height to diameter impracticable4 ,the method to be recommended in overcoming1 at least partially1 the great increase in height necessary at high altitudes is an increase in the grate surface of the boilers which the stack serves1 in this way reducing the combustion rate necessary to develop a given power and hence the draft required for such combustion rate4 ,,table #ee ,,stack ,,sizes ,,by ,,kent',s ,,formula ,,assuming #e ,,pounds ,,of ,,coal ,,per ,,horse ,,power ,height of ,stack in ,feet ,side of ,equiva- ,dia- ,area lent meter,square #ej #fj #gj #hj #ij #ajj #aaj #abe #aej #age,square ,inches ,feet ,stack ,inches ,commercial ,horse ,power #cc #e4idajfaaeabe #acc #ada #adi #cj #cf #g4jgabiadaaeb #afc #agc #ahb #cb #ci #h4cjaeeafiahc #aif #bjh #bai #bbi #bde #ce #db #i4fbahcbjjbaf #bca #bde #beh #bga #bhi #caf #ch #dh #ab4egbdfbfibij #caa #ccj #cdh #cfe #chi #dbf #dfj #dc #ed #ae4ijcahcdhcgf #djb #dbg #ddi #dgb #ejc #eea #eie #dh #fj #ai4fddjjdcgdgc #eje #ecf #efe #eic #fcb #fib #gdh #ed #ff #bc4gfdijecgehj #fbj #feh #fid #gbh #ggf #hdi #iah #ei #gb #bh4bgeiafdffih #gdg #gib #hce #hgf #icdajbcaaje #fd #gh #cc4ahgjjgffhbh #hhe #ici #iijajchaajgababacaj #gj #hd #ch4dhhahhififhajceajihaaegabadabidadaha eca #ge ,height of ,stack in ,feet ,side of ,equiva- ,dia- ,area lent meter,square #ajj #aaj #abe #aej #age #bjj #bbe #bej ,square ,inches ,feet ,stack ,inches ,commercial ,horse ,power #ij #dd4ahacch #adjc #adif #afci #aggj #ahic #bjjh #baaf #hj #if #ej4bgaecb #afjf #agac #ahgf #bjbg #bafg #bbih #bdbc #hf #ajb #ef4geagci #ahbd #aidd #bacj #bcjj #bdei #bfji #bgej #ia #ajh #fc4fbaiei #bjed #baij #bcib #beib #bggj #bici #cjih #ih #aad #gj4hhbaib #bbii #bdea #bfhe #bijj #cajj #cbhh #cdff #aja #abj #gh4edbdch #beeg #bgbf #bihf #cbbf #cddh #cfeg #chee #ajg #abf #hf4eibfig #bhbi #cjaf #ccjc #cefh #chad #djdf #dbfe #aab #acb #ie4jcbigj #caad #ccba #cfcg #cibi #dbjj #ddee #dfif #aag #add #aac4ajceed #cgbf #cigc #dceb #dgja #ejbf #ecca #efah #abh #aef #acb4gcdaij #dcic #dfhd #eaca #eedb #eibe #fbhe #ffbd #ach #afh #aec4iddhgh #eaae #eded #eigd #fded #fhii #gcah #ggac #aej ,kent's ,stack ,tables--,table #ee gives1 in convenient form for approximate work1 the sizes of stacks and the horse power of boilers which they will serve4 ,this table is a modification of ,mr4 ,william ,kent's stack table and is calculated from his formula4 ,provided no unusual conditions are encountered1 it is reliable for the ordinary rates of combustion with bituminous coals4 ,it is figured on a consumption of #e pounds of coal burned per hour per boiler horse power developed1 this figure giving a fairly liberal allowance for the use of poor coal and for a reasonable overload4 ,when the coal used is a low grade bituminous of the ,middle or ,western ,states1 it is strongly recommended that these sizes be increased materially1 such an increase being from #be to #fj per cent1 depending upon the nature of the coal and the capacity desired4 ,for the coal burned per hour for any size stack given in the table1 the values should be multiplied by #e4 ,a convenient rule for large stacks1 #bjj feet high and over1 is to provide #cj square feet of cross sectional area per #ajjj rated horse power4 ,stacks for ,oil ,fuel--,the requirements of stacks connected to boilers under which oil fuel is burned are entirely different from those where coal is used4 ,while more attention has been paid to the matter of stack sizes for oil fuel in recent years1 there has not as yet been gathered the large amount of experimental data available for use in designing coal stacks4 ,in the case of oil-fired boilers the loss of draft through the fuel bed is partially eliminated4 ,while there may be practically no loss through any checkerwork admitting air to the furnace when a boiler is new1 the areas for the air passage in this checkerwork will in a short time be decreased1 due to the silt which is present in practically all fuel oil4 ,the loss in draft through the boiler proper at a given rating will be less than in the case of coal-fired boilers1 this being due to a decrease in the volume of the gases4 ,further1 the action of the oil burner itself is to a certain extent that of a forced draft4 ,to offset this decrease in draft requirement1 the temperature of the gases entering the stack will be somewhat lower where oil is used than where coal is used1 and the draft that a stack of a given height would give1 therefore1 decreases4 ,the factors as given above1 affecting as they do the intensity of the draft1 affect directly the height of the stack to be used4 ,as already stated1 the volume of gases from oil-fired boilers being less than in the case of coal1 makes it evident that the area of stacks for oil fuel will be less than for coal4 ,it is assumed that these areas will vary directly as the volume of the gases to be handled1 and this volume for oil may be taken as approximately #fj per cent of that for coal4 ,in designing stacks for oil fuel there are two features which must not be overlooked4 ,in coal-firing practice there is rarely danger of too much draft4 ,in the burning of oil1 however1 this may play an important part in the reduction of plant economy1 the influence of excessive draft being more apparent where the load on the plant may be reduced at intervals4 ,the reason for this is that1 aside from a slight decrease in temperature at reduced loads1 the tendency1 due to careless firing1 is toward a constant gas flow through the boiler regardless of the rate of operation1 with the corresponding increase of excess air at light loads4 ,with excessive stack height1 economical operation at varying loads is almost impossible with hand control4 ,with automatic control1 however1 where stacks are necessarily high to take care of known peaks1 under lighter loads this economical operation becomes less difficult4 ,for this reason the question of designing a stack for a plant where the load is known to be nearly a constant is easier than for a plant where the load will vary over a wide range4 ,while great care must be taken to avoid excessive draft1 still more care must be taken to assure a draft suction within all parts of the setting under any and all conditions of operation4 ,it is very easily possible to more than offset the economy gained through low draft1 by the losses due to setting deterioration1 resulting from such lack of suction4 ,under conditions where the suction is not sufficient to carry off the products of combustion1 the action of the heat on the setting brickwork will cause its rapid failure4 ,illustration3 #ghjj ,horse-power ,installation of ,babcock ,wilcox ,boilers1 ,equipped with ,babcock ,wilcox ,chain ,grate ,stokers at the ,metropolitan ,west ,side ,elevated ,ry4 ,co41 ,chicago1 ,ill4 ,it becomes evident1 therefore1 that the question of stack height for oil-fired boilers is one which must be considered with the greatest of care4 ,the designer1 on the one hand1 must guard against the evils of excessive draft with the view to plant economy1 and1 on the other1 against the evils of lack of draft from the viewpoint of upkeep cost4 ,stacks for this work should be proportioned to give ample draft for the maximum overload that a plant will be called upon to carry1 all conditions of overload carefully considered4 ,at the same time1 where this maximum overload is figured liberally enough to insure a draft suction within the setting under all conditions1 care must be taken against the installation of a stack which would give more than this maximum draft4 ,,table #ef ,,stack ,,sizes ,,for ,,oil ,,fuel ,,adapted ,,from ,c4 ,r4 ,,weymouth',s ,,table 7,,trans4 ,a4 ,s4 ,m4 ,e4 ,,vol4 #cd7 ---------------------------------------- ------------ ---------------------------------------- --------- ,height in ,feet ,above ,boiler ,room ,floor ,diameter------------------------------- ------ ,inches #hj #ij #ajj #abj #adj #afj ---------------------------------------- ---- #cc #afa #bjf #bcc #bgj #cjf #cae #cf #bjh #bec #bie #cca #cfc #chg #ci #bea #cjc #cdc #cii #dhh #dfg #db #bie #cei #djc #dgd #eba #eeg #dh #cii #dhf #eea #fde #gac #gfj #ed #eai #fcd #gbj #hdg #icc #ajjj #fj #feg #hjj #iac #ajgc #aaic #abhj #ff #hac #iic #aacc #accc #adhj #aeic #gb #ihj #abjf #acgc #afbj #ahjg #aidj #hd #acgc #aehg #aicc #bbic #befj #bgfg #if #ahcc #bbfj #behg #cjhg #cdec #cgdj #ajh #bcfg #bibj #ccdg #djjj #ddhc #dhfg #abj #cjfj #cffj #dbjg #ejdj #effj #fafj ---------------------------------------- ---- ---------------------------------------- ------------ ,figures represent nominal rated horse power4 ,sizes as given good for #ej per cent overloads4 ,based on centrally located stacks1 short direct flues and ordinary operating efficiencies4 ,table #ef gives the sizes of stacks1 and horse power which they will serve for oil fuel4 ,this table is1 in modified form1 one calculated by ,mr4 ,c4 ,r4 ,weymouth after an exhaustive study of data pertaining to the subject1 and will ordinarily give satisfactory results4 ,stacks for ,blast ,furnace ,gas ,work--,for boilers burning blast furnace gas1 as in the case of oil-fired boilers1 stack sizes as suited for coal firing will have to be modified4 ,the diameter of stacks for this work should be approximately the same as for coal-fired boilers4 ,the volume of gases would be slightly greater than from a coal fire and would decrease the draft with a given stack1 but such a decrease due to volume is about offset by an increase due to somewhat higher temperatures in the case of the blast furnace gases4 ,records show that with this class of fuel #age per cent of the rated capacity of a boiler can be developed with a draft at the boiler damper of from #j4ge inch to #a4j inch1 and it is well to limit the height of stacks to one which will give this draft as a maximum4 ,a stack of proper diameter1 #acj feet high above the ground1 will produce such a draft and this height should ordinarily not be exceeded4 ,until recently the question of economy in boilers fired with blast furnace gas has not been considered1 but1 aside from the economical standpoint1 excessive draft should be guarded against in order to lower the upkeep cost4 ,stacks should be made of sufficient height to produce a draft that will develop the maximum capacity required1 and this draft decreased proportionately for loads under the maximum by damper regulation4 ,the amount of gas fed to a boiler for any given rating is a fixed quantity and if a draft in excess of that required for that particular rate of operation is supplied1 economy is decreased and the wear and tear on the setting is materially increased4 ,excess air which is drawn in1 either through or around the gas burners by an excessive draft1 will decrease economy1 as in any other class of work4 ,again1 as in oil-fired practice1 it is essential on the other hand that a suction be maintained within all parts of the setting1 in this case not only to provide against setting deterioration but to protect the operators from leakage of gas which is disagreeable and may be dangerous4 ,aside from the intensity of the draft1 a poor mixture of the gas and air or a laneing action may lead to secondary combustion with the possibility of dangerous explosions within the setting1 may cause a pulsating action within the setting1 may increase the exit temperatures to a point where there is danger of burning out damper boxes1 and1 in general1 is hard on the setting4 ,it is highly essential1 therefore1 that the furnace be properly constructed to meet the draft which will be available4 ,stacks for ,wood-fired ,boilers--,for boilers using wood as fuel1 there is but little data upon which to base stack sizes4 ,the loss of draft through the bed of fuel will vary over limits even wider than in the case of coal1 for in this class of fuel the moisture may run from practically #j4j per cent to over #fj per cent1 and the methods of handling and firing are radically different for the different classes of wood 7see chapter on ,wood-burning ,furnaces74 ,as economy is ordinarily of little importance1 high stack temperatures may be expected1 and often unavoidably large quantities of excess air are supplied due to the method of firing4 ,in general1 it may be stated that for this class of fuel the diameter of stacks should be at least as great as for coal-fired boilers1 while the height may be slightly decreased4 ,it is far the best plan in designing a stack for boilers using wood fuel to consider each individual set of conditions that exist1 rather than try to follow any general rule4 ,one factor not to be overlooked in stacks for wood burning is their location4 ,the fine particles of this fuel are often carried unconsumed through the boiler1 and where the stack is not on top of the boiler1 these particles may accumulate in the base of the stack below the point at which the flue enters4 ,where there is any air leakage through the base of such a stack1 this fuel may become ignited and the stack burned4 ,where there is a possibility of such action taking place1 it is well to line the stack with fire brick for a portion of its height4 ,draft ,gauges--,the ordinary form of draft gauge1 ,fig4 #ce1 which consists of a ,u-tube1 containing water1 lacks sensitiveness in measuring such slight pressure differences as usually exist1 and for that reason gauges which multiply the draft indications are more convenient and are much used4 ,illustration3 ,fig4 #ce4 ,u-tube ,draft ,gauge ,illustration3 ,fig4 #cf4 ,barrus ,draft ,gauge ,an instrument which has given excellent results is one introduced by ,mr4 ,g4 ,h4 ,barrus1 which multiplies the ordinary indications as many times as desired4 ,this is illustrated in ,fig4 #cf1 and consists of a ,u-tube made of one-half inch glass1 surmounted by two larger tubes1 or chambers1 each having a diameter of #b inches4 ,two different liquids which will not mix1 and which are of different color1 are used1 usually alcohol colored red and a certain grade of lubricating oil4 ,the movement of the line of demarcation is proportional to the difference in the areas of the chambers and the ,u-tube connecting them4 ,the instrument is calibrated by comparison with the ordinary ,u-tube gauge4 ,in the ,ellison form of gauge the lower portion of the ordinary ,u-tube has been replaced by a tube slightly inclined to the horizontal1 as shown in ,fig4 #cg4 ,by this arrangement any vertical motion in the right-hand upright tube causes a very much greater travel of the liquid in the inclined tube1 thus permitting extremely small variation in the intensity of the draft to be read with facility4 ,illustration3 ,fig4 #cg4 ,ellison ,draft ,gauge ,the gauge is first leveled by means of the small level attached to it1 both legs being open to the atmosphere4 ,the liquid is then adjusted until its meniscus rests at the zero point on the left4 ,the right-hand leg is then connected to the source of draft by means of a piece of rubber tubing4 ,under these circumstances1 a rise of level of one inch in the right-hand vertical tube causes the meniscus in the inclined tube to pass from the point #j to #a4j4 ,the scale is divided into tenths of an inch1 and the sub-divisions are hundredths of an inch4 ,the makers furnish a non-drying oil for the liquid1 usually a #cjj degrees test refined petroleum4 ,a very convenient form of the ordinary ,u-tube gauge is known as the ,peabody gauge1 and it is shown in ,fig4 #ch4 ,this is a small modified ,u-tube with a sliding scale between the two legs of the ,u and with connections such that either a draft suction or a draft pressure may be taken4 ,the tops of the sliding pieces extending across the tubes are placed at the bottom of the meniscus and accurate readings in hundredths of an inch are obtained by a vernier4 ,illustration3 ,fig4 #ch4 ,peabody ,draft ,gauge ,,efficiency ,,and ,,capacity ,,of ,,boilers ,two of the most important operating factors entering into the consideration of what constitutes a satisfactory boiler are its efficiency and capacity4 ,the relation of these factors to one another will be considered later under the selection of boilers with reference to the work they are to accomplish4 ,the present chapter deals with the efficiency and capacity only with a view to making clear exactly what is meant by these terms as applied to steam generating apparatus1 together with the methods of determining these factors by tests4 ,efficiency--,the term efficiency1 specifically applied to a steam boiler1 is the ratio of heat absorbed by the boiler in the generation of steam to the total amount of heat available in the medium utilized in securing such generation4 ,when this medium is a solid fuel1 such as coal1 it is impossible to secure the complete combustion of the total amount fed to the boiler4 ,a portion is bound to drop through the grates where it becomes mixed with the ash and1 remaining unburned1 produces no heat4 ,obviously1 it is unfair to charge the boiler with the failure to absorb the portion of available heat in the fuel that is wasted in this way4 ,on the other hand1 the boiler user must pay for such waste and is justified in charging it against the combined boiler and furnace4 ,due to this fact1 the efficiency of a boiler1 as ordinarily stated1 is in reality the combined efficiency of the boiler1 furnace and grate1 and ,efficiency of boiler1 ,heat absorbed per pound of fuel furnace and grate ------------------------------- 7#ca7 ,heat value per pound of fuel ,the efficiency will be the same whether based on dry fuel or on fuel as fired1 including its content of moisture4 ,for example3 ,if the coal contained #c per cent of moisture1 the efficiency would be ,heat absorbed per pound of dry coal #j4ig ---------------------------------------- -- ,heat value per pound of dry coal #j4ig where #j4ig cancels and the formula becomes 7#ca74 ,the heat supplied to the boiler is due to the combustible portion of fuel which is actually burned1 irrespective of what proportion of the total combustible fired may be4#ed ,this fact has led to the use of a second efficiency basis on combustible and which is called the efficiency of boiler and furnace#ee1 namely1 ,efficiency of boiler and furnace#ee ,heat absorbed per pound of combustible#ef -------------------------------------- 7#cb7 ,heat value per pound of combustible ,the efficiency so determined is used in comparing the relative performance of boilers1 irrespective of the type of grates used under them4 ,if the loss of fuel through the grates could be entirely overcome1 the efficiencies obtained by 7#ca7 and 7#cb7 would obviously be the same4 ,hence1 in the case of liquid and gaseous fuels1 where there is practically no waste1 these efficiencies are almost identical4 ,as a matter of fact1 it is extremely difficult1 if not impossible1 to determine the actual efficiency of a boiler alone1 as distinguished from the combined efficiency of boiler1 grate and furnace4 ,this is due to the fact that the losses due to excess air cannot be correctly attributed to either the boiler or the furnace1 but only to a combination of the complete apparatus4 ,attempts have been made to devise methods for dividing the losses proportionately between the furnace and the boiler1 but such attempts are unsatisfactory and it is impossible to determine the efficiency of a boiler apart from that of a furnace in such a way as to make such determination of any practical value or in a way that might not lead to endless dispute1 were the question to arise in the case of a guaranteed efficiency4 ,from the boiler manufacturer's standpoint1 the only way of establishing an efficiency that has any value when guarantees are to be met1 is to require the grate or stoker manufacturer to make certain guarantees as to minimum ,,co#b1 maximum ,,co1 and that the amount of combustible in the ash and blown away with the flue gases does not exceed a certain percentage4 ,with such a guarantee1 the efficiency should be based on the combined furnace and boiler4 ,general practice1 however1 has established the use of the efficiency based upon combustible as representing the efficiency of the boiler alone4 ,when such an efficiency is used1 its exact meaning1 as pointed out on opposite page1 should be realized4 ,the computation of the efficiencies described on opposite page is best illustrated by example4 ,assume the following data to be determined from an actual boiler trial4 ,steam pressure by gauge1 #bjj pounds4 ,feed temperature1 #ahj degrees4 ,total weight of coal fired1 #ag1ejj pounds4 ,percentage of moisture in coal1 #c per cent4 ,total ash and refuse1 #bcif pounds4 ,total water evaporated1 #aec1edc pounds4 ,per cent of moisture in steam1 #j4e per cent4 ,heat value per pound of dry coal1 #ac1eaf4 ,heat value per pound of combustible1 #ae1cei4 ,the factor of evaporation for such a set of conditions is #a4jhcd4 ,the actual evaporation corrected for moisture in the steam is #aeb1gge and the equivalent evaporation from and at #bab degrees is1 therefore1 #afe1eaf pounds4 ,the total dry fuel will be #ag1ejj 4#ig #af1ige1 and the evaporation per pound of dry fuel from and at #bab degrees will be #afe1eaf #af1ige #i4ge pounds4 ,the heat absorbed per pound of dry fuel will1 therefore1 be #i4ge #igj4d #idfa ,b4 t4 u4 ,hence1 the efficiency by 7#ca7 will be #idfa #ac1eaf #gj4j per cent4 ,the total combustible burned will be #af1ige - #bcif #ad1egi1 and the evaporation from and at #bab degrees per pound of combustible will be #afe1eaf #ad1egi #aa4ce pounds4 ,hence1 the efficiency based on combustible from 7#cb7 will be 7#aa4ce #ig4jd7 #ae1cei #ga4gi49999should be #ga4ga ,for approximate results1 a chart may be used to take the place of a computation of efficiency4 ,fig4 #ci shows such a chart based on the evaporation per pound of dry fuel and the heat value per pound of dry fuel1 from which efficiencies may be read directly to within one-half of one per cent4 ,it is used as follows3 ,from the intersection of the horizontal line1 representing the evaporation per pound of fuel1 with the vertical line1 representing the heat value per pound1 the efficiency is read directly from the diagonal scale of efficiencies4 ,this chart may also be used for efficiency based upon combustible when the evaporation from and at #bab degrees and the heat values are both given in terms of combustible4 ,graph3 ,evaporation from and at #bab per ,pound of ,dry ,fuel against ,b4,t4,u4 per ,pound of ,dry ,fuel ,fig4 #ci4 ,efficiency ,chart4 ,calculated from ,marks and ,davis ,tables ,diagonal ,lines ,represent ,per ,cent ,efficiency ,boiler efficiencies will vary over a wide range1 depending on a great variety of factors and conditions4 ,the highest efficiencies that have been secured with coal are in the neighborhood of #hb per cent and from that point efficiencies are found all the way down to below #ej per cent4 ,table #eieg of tests of ,babcock ,wilcox boilers under varying conditions of fuel and operation will give an idea of what may be obtained with proper operating conditions4 ,the difference between the efficiency secured in any boiler trial and the perfect efficiency1 #ajj per cent1 includes the losses1 some of which are unavoidable in the present state of the art1 arising in the conversion of the heat energy of the coal to the heat energy in the steam4 ,these losses may be classified as follows3 #ast4 ,loss due to fuel dropped through the grate4 #bnd4 ,loss due to unburned fuel which is carried by the draft1 as small particles1 beyond the bridge wall into the setting or up the stack4 #crd4 ,loss due to the utilization of a portion of the heat in heating the moisture contained in the fuel from the temperature of the atmosphere to #bab degrees2 to evaporate it at that temperature and to superheat the steam thus formed to the temperature of the flue gases4 ,this steam1 of course1 is first heated to the temperature of the furnace but as it gives up a portion of this heat in passing through the boiler1 the superheating to the temperature of the exit gases is the correct degree to be considered4 #dth4 ,loss due to the water formed and by the burning of the hydrogen in the fuel which must be evaporated and superheated as in item #c4 #eth4 ,loss due to the superheating of the moisture in the air supplied from the atmospheric temperature to the temperature of the flue gases4 #fth4 ,loss due to the heating of the dry products of combustion to the temperature of the flue gases4 #gth4 ,loss due to the incomplete combustion of the fuel when the carbon is not completely consumed but burns to ,,co instead of ,,co#b4 ,the ,,co passes out of the stack unburned as a volatile gas capable of further combustion4 #hth4 ,loss due to radiation of heat from the boiler and furnace settings4 ,obviously a very elaborate test would have to be made were all of the above items to be determined accurately4 ,in ordinary practice it has become customary to summarize these losses as follows1 the methods of computing the losses being given in each instance by a typical example3 7,a7 ,loss due to the heating of moisture in the fuel from the atmospheric temperature to #bab degrees1 evaporate it at that temperature and superheat it to the temperature of the flue gases4 ,this in reality is the total heat above the temperature of the air in the boiler room1 in one pound of superheated steam at atmospheric pressure at the temperature of the flue gases1 multiplied by the percentage of moisture in the fuel4 ,as the total heat above the temperature of the air would have to be computed in each instance1 this loss is best expressed by3 ,loss in ,b4 t4 u4 per pound ,w7#bab-t#igj4d4dg7,t-#bab77 7#cc7 ,where ,w per cent of moisture in coal1 t the temperature of air in the boiler room1 ,t temperature of the flue gases1 4#dg the specific heat of superheated steam at the atmospheric pressure and at the flue gas temperature1 7#bab-t7 ,b4 t4 u4 necessary to heat one pound of water from the temperature of the boiler room to #bab degrees1 #igj4d ,b4 t4 u4 necessary to evaporate one pound of water at #bab degrees to steam at atmospheric pressure1 4#dg7,t-#bab7 ,b4 t4 u4 necessary to superheat one pound of steam at atmospheric pressure from #bab degrees to temperature ,t4 ,illustration3 ,portion of #ae1jjj ,horse-power ,installation of ,babcock ,wilcox ,boilers1 ,equipped with ,babcock ,wilcox ,chain ,grate ,stokers at the ,northumberland1 ,pa41 ,plant of the ,atlas ,portland ,cement ,co4 ,this ,company ,operates a ,total of #bd1jjj ,horse ,power of ,babcock ,wilcox ,boilers in its ,various ,plants 7,b7 ,loss due to heat carried away in the steam produced by the burning of the hydrogen component of the fuel4 ,in burning1 one pound of hydrogen unites with #h pounds of oxygen to form #i pounds of steam4 ,following the reasoning of item 7,a71 therefore1 this loss will be3 ,loss in ,b4 t4 u4 per pound #i;,h77#bab-t7#igj4d4dg7,t-#bab77 7#cd7 where ,h the percentage by weight of hydrogen4 ,this item is frequently considered as a part of the unaccounted for loss1 where an ultimate analysis of the fuel is not given4 7,c7 ,loss due to heat carried away by dry chimney gases4 ,this is dependent upon the weight of gas per pound of coal which may be determined by formula 7#af71 page #aeh4 ,loss in ,b4 t4 u4 per pound 7,t-t74#bd,w4 ,where ,t and t have values as in 7#cc71 4#bd specific heat of chimney gases1 ,w weight of dry chimney gas per pound of coal4 7,d7 ,loss due to incomplete combustion of the carbon content of the fuel1 that is1 the burning of the carbon to ,,co instead of ,,co#b4 #aj1aej ,,co ,loss in ,b4 t4 u4 per pound ,c--------- 7#ce7 ,,co#b;,,co ,c per cent of carbon in coal by ultimate analysis1 ,,co and ,,co#b per cent of ,,co and ,,co#b by volume from flue gas analysis4 #aj1aej the number of heat units generated by burning to ,,co#b one pound of carbon contained in carbon monoxide4 7,e7 ,loss due to unconsumed carbon in the ash 7it being usually assumed that all the combustible in the ash is carbon74 ,loss in ,b4 t4 u4 per pound per cent ,c per cent ash ,b4 t4 u4 per pound of combustible in the ash 7usually taken as #ad1fjj ,b4 t4 u47 7#cf7 ,the loss incurred in this way is1 directly1 the carbon in the ash in percentage terms of the total dry coal fired1 multiplied by the heat value of carbon4 ,to compute this item1 which is of great importance in comparing the relative performances of different designs of grates1 an analysis of the ash must be available4 ,the other losses1 namely1 items #b1 #e and #h of the first classification1 are ordinarily grouped under one item1 as unaccounted for losses1 and are obviously the difference between #ajj per cent and the sum of the heat utilized and the losses accounted for as given above4 ,item #e1 or the loss due to the moisture in the air1 may be readily computed1 the moisture being determined from wet and dry bulb thermometer readings1 but it is usually disregarded as it is relatively small1 averaging1 say1 one-fifth to one-half of one per cent4 ,lack of data may1 of course1 make it necessary to include certain items of the second and ordinary classification in this unaccounted for group4 ,,table #eg ,,data ,,from ,,which ,,heat ,,balance 7,,table #eh7 ,,is ,,computed ---------------------------------------- -------------- ---------------------------------------- ------------ ,steam ,pressure by ,gauge1 ,pounds #aib ,temperature of ,feed1 ,degrees ,fahrenheit #ahj ,degrees of ,superheat1 ,degrees ,fahrenheit #aae4b ,temperature of ,boiler ,room1 ,degrees ,fahrenheit #ha ,temperature of ,exit ,gases1 ,degrees ,fahrenheit #dhj ,weight of ,coal ,used per ,hour1 ,pounds #egad ,moisture1 ,per ,cent #a4hc ,dry ,coal ,per ,hour1 ,pounds #efji ,ash and ,refuse per ,hour1 ,pounds #efa ,ash and ,refuse 7of ,dry ,coal71 ,per ,cent #aj4jj ,actual ,evaporation per ,hour1 ,pounds #egjcf 4- ,c1 ,per ,cent #gh4eg ,h1 ,per ,cent #e4fj ,ultimate ,o1 ,per ,cent #g4jb ,analysis - ,n1 ,per ,cent #a4aa ,dry ,coal ,ash1 ,per ,cent #f4eb '- ,sulphur1 ,per ,cent #a4ah ,heat ,value per ,pound ,dry ,coal1 ,b4 t4 u4 #adbbe ,heat ,value per ,pound ,combustible1 ,b4 t4 u4 #aebag ,combustible in ,ash by ,analysis1 ,per ,cent #ag4i 4- ,,co#b1 ,per ,cent #ad4cc ,flue ,gas - ,o1 ,per ,cent #d4ed ,analysis ,,co1 ,per ,cent #j4aa '- ,n1 ,per ,cent #ha4jb ---------------------------------------- ----------- ---------------------------------------- -------------- ,a schedule of the losses as outlined1 requires an evaporative test of the boiler1 an analysis of the flue gases1 an ultimate analysis of the fuel1 and either an ultimate or proximate analysis of the ash4 ,as the amount of unaccounted for losses forms a basis on which to judge the accuracy of a test1 such a schedule is called a heat balance4 ,a heat balance is best illustrated by an example3 ,assume the data as given in ,table #eg to be secured in an actual boiler test4 ,from this data the factor of evaporation is #a4aead and the evaporation per hour from and at #bab degrees is #fe1fga pounds4 ,hence the evaporation from and at #bab degrees per pound of dry coal is #fe1fgaefji #aa4ga pounds4 ,the efficiency of boiler1 furnace and grate is3 7#aa4gaigj4d7ad1bbe #gi4hh per cent4 ,the heat losses are3 7,a7 ,loss due to moisture in coal1 4#jahca 77#bab-ha7igj4d4dg7dhj-bab77 #bb4 ,b4 t4 u41 #j4ae per cent4 7,b7 ,the loss due to the burning of hydrogen3 #i4jefj77bab-ha7igj4d4dg7dhj-bab77 #fah ,b4 t4 u41 #d4cd per cent4 7,c7 ,to compute the loss in the heat carried away by dry chimney gases per pound of coal the weight of such gases must be first determined4 ,this weight per pound of coal is3 7#aa;,,co#bh,o#g7;,,co,n77 7-------------------7,c 7 #c7;,,co#b;,,co7 7 where ,,co#b1 ,o1 ,,co and ,h are the percentage by volume as determined by the flue gas analysis and ,c is the percentage by weight of carbon in the dry fuel4 ,hence the weight of gas per pound of coal will be1 7#aaad4cchd4edg7j4aaha4jb77 7-----------------------------7#gh4eg #ac4g pounds4 7 #c7ad4ccj4aa7 7 ,therefore the loss of heat in the dry gases carried up the chimney #ac4gj4bd7dhj-ha7 #acaa ,b4 t4 u41 #i4bb per cent4 7,d7 ,the loss due to incomplete combustion as evidenced by the presence of ,,co in the flue gas analysis is3 #j4aa ----------4#ghegaj1aej #fa4 ,b4 t4 u41 #ad4ccj4aa 4#dc per cent4 7,e7 ,the loss due to unconsumed carbon in the ash3 ,the analysis of the ash showed #ag4i per cent to be combustible matter1 all of which is assumed to be carbon4 ,the test showed #aj4jj of the total dry fuel fired to be ash4 ,hence #aj4jj4agi #a4gi per cent of the total fuel represents the proportion of this total unconsumed in the ash and the loss due to this cause is #a4gi per cent #ad1fjj #bfa ,b4 t4 u41 #a4hc per cent4 ,the heat absorbed by the boilers per pound of dry fuel is #aa4gaigj4d #aa1cfc ,b4 t4 u4 ,this quantity plus losses 7,a71 7,b71 7,c71 7,d7 and 7,e71 or #aa1cfcbbfahacaafabfa #ac1fcf ,b4 t4 u4 accounted for4 ,the heat value of the coal1 #ad1bbe ,b4 t4 u41 less #ac1fcf ,b4 t4 u41 leaves #ehi ,b4 t4 u41 unaccounted for losses1 or #d4ae per cent4 ,the heat balance should be arranged in the form indicated by ,table #eh4 ,,table #eh ,,heat ,,balance ,b4 ,t4 ,u4 ,,per ,,pound ,,dry ,,coal #ad1bbe ---------------------------------------- ------------------------------ ---------------------------------------- ---------------------------- ,b4 t4 u4,per ,cent ---------------------------------------- -------------------------- ,heat absorbed by ,boiler #aa1cfc #gi4hh ,loss due to ,evaporation of ,moisture in ,fuel #bb #j4ae ,loss due to ,moisture formed by ,burning of ,hydrogen #fah #d4cd ,loss due to ,heat carried away in ,dry ,chimney ,gases #acaa #i4bb ,loss due to ,incomplete ,combustion of ,carbon #fa #j4dc ,loss due to ,unconsumed ,carbon in the ,ash #bfa #a4hc ,loss due to ,radiation and ,unaccounted ,losses #ehi #d4ae ---------------------------------------- -------------------------- ,total #ad1bbe #ajj4jj ---------------------------------------- -------------------------- ---------------------------------------- ------------------------------ ,application of ,heat ,balance--,a heat balance should be made in connection with any boiler trial on which sufficient data for its computation has been obtained4 ,this is particularly true where the boiler performance has been considered unsatisfactory4 ,the distribution of the heat is thus determined and any extraordinary loss may be detected4 ,where accurate data for computing such a heat balance is not available1 such a calculation based on certain assumptions is sometimes sufficient to indicate unusual losses4 ,the largest loss is ordinarily due to the chimney gases1 which depends directly upon the weight of the gas and its temperature leaving the boiler4 ,as pointed out in the chapter on flue gas analysis1 the lower limit of the weight of gas is fixed by the minimum air supplied with which complete combustion may be obtained4 ,as shown1 where this supply is unduly small1 the loss caused by burning the carbon to ,,co instead of to ,,co#b more than offsets the gain in decreasing the weight of gas4 ,the lower limit of the stack temperature1 as has been shown in the chapter on draft1 is more or less fixed by the temperature necessary to create sufficient draft suction for good combustion4 ,with natural draft1 this lower limit is probably between #djj and #dej degrees4 ,capacity--,before the capacity of a boiler is considered1 it is necessary to define the basis to which such a term may be referred4 ,such a basis is the so-called boiler horse power4 ,the unit of motive power in general use among steam engineers is the horse power which is equivalent to #cc1jjj foot pounds per minute4 ,stationary boilers are at the present time rated in horse power1 though such a basis of rating may lead and has often led to a misunderstanding4 ,work1 as the term is used in mechanics1 is the overcoming of resistance through space1 while power is the rate of work or the amount done per unit of time4 ,as the operation of a boiler in service implies no motion1 it can produce no power in the sense of the term as understood in mechanics4 ,its operation is the generation of steam1 which acts as a medium to convey the energy of the fuel which is in the form of heat to a prime mover in which that heat energy is converted into energy of motion or work1 and power is developed4 ,if all engines developed the same amount of power from an equal amount of heat1 a boiler might be designated as one having a definite horse power1 dependent upon the amount of engine horse power its steam would develop4 ,such a statement of the rating of boilers1 though it would still be inaccurate1 if the term is considered in its mechanical sense1 could1 through custom1 be interpreted to indicate that a boiler was of the exact capacity required to generate the steam necessary to develop a definite amount of horse power in an engine4 ,such a basis of rating1 however1 is obviously impossible when the fact is considered that the amount of steam necessary to produce the same power in prime movers of different types and sizes varies over very wide limits4 ,to do away with the confusion resulting from an indefinite meaning of the term boiler horse power1 the ,committee of ,judges in charge of the boiler trials at the ,centennial ,exposition1 #ahgf1 at ,philadelphia1 ascertained that a good engine of the type prevailing at the time required approximately #cj pounds of steam per hour per horse power developed4 ,in order to establish a relation between the engine power and the size of a boiler required to develop that power1 they recommended that an evaporation of #cj pounds of water from an initial temperature of #ajj degrees ,fahrenheit to steam at #gj pounds gauge pressure be considered as one boiler horse power4 ,this recommendation has been generally accepted by ,american engineers as a standard1 and when the term boiler horse power is used in connection with stationary boilers#eh throughout this country1#ei without special definition1 it is understood to have this meaning4 ,inasmuch as an equivalent evaporation from and at #bab degrees ,fahrenheit is the generally accepted basis of comparison#fj1 it is now customary to consider the standard boiler horse power as recommended by the ,centennial ,exposition ,committee1 in terms of equivalent evaporation from and at #bab degrees4 ,this will be #cj pounds multiplied by the factor of evaporation for #gj pounds gauge pressure and #ajj degrees feed temperature1 or #a4adid4 #cj #a4adid #cd4dhb1 or approximately #cd4e pounds4 ,hence1 one boiler horse power is equal to an evaporation of #cd4e pounds of water per hour from and at #bab degrees ,fahrenheit4 ,the term boiler horse power1 therefore1 is clearly a measure of evaporation and not of power4 ,a method of basing the horse power rating of a boiler adopted by boiler manufacturers is that of heating surfaces4 ,such a method is absolutely arbitrary and changes in no way the definition of a boiler horse power just given4 ,it is simply a statement by the manufacturer that his product1 under ordinary operating conditions or conditions which may be specified1 will evaporate #cd4e pounds of water from and at #bab degrees per definite amount of heating surface provided4 ,the amount of heating surface that has been considered by manufacturers capable of evaporating #cd4e pounds from and at #bab degrees per hour has changed from time to time as the art has progressed4 ,at the present time #aj square feet of heating surface is ordinarily considered the equivalent of one boiler horse power among manufacturers of stationary boilers4 ,in view of the arbitrary nature of such rating and of the widely varying rates of evaporation possible per square foot of heating surface with different boilers and different operating conditions1 such a basis of rating has in reality no particular bearing on the question of horse power and should be considered merely as a convenience4 ,the whole question of a unit of boiler capacity has been widely discussed with a view to the adoption of a standard to which there would appear to be a more rational and definite basis4 ,many suggestions have been offered as to such a basis but up to the present time there has been none which has met with universal approval or which would appear likely to be generally adopted4 ,with the meaning of boiler horse power as given above1 that is1 a measure of evaporation1 it is evident that the capacity of a boiler is a measure of the power it can develop expressed in boiler horse power4 ,since it is necessary1 as stated1 for boiler manufacturers to adopt a standard for reasons of convenience in selling1 the horse power for which a boiler is sold is known as its normal rated capacity4 ,the efficiency of a boiler and the maximum capacity it will develop can be determined accurately only by a boiler test4 ,the standard methods of conducting such tests are given on the following pages1 these methods being the recommendations of the ,power ,test ,committee of the ,american ,society of ,mechanical ,engineers brought out in #aiac4fa ,certain changes have been made to incorporate in the boiler code such portions of the ,instructions ,regarding ,tests in ,general as apply to boiler testing4 ,methods of calculation and such matter as are treated in other portions of the book have been omitted from the code as noted4 ,illustration3 ,portion of #bfjj ,horse-power ,installation of ,babcock ,wilcox ,boilers1 ,equipped with ,babcock ,wilcox ,chain ,grate ,stokers at the ,peter ,schoenhofen ,brewing ,co41 ,chicago1 ,ill4 #a4 ,,object ,ascertain the specific object of the test1 and keep this in view not only in the work of preparation1 but also during the progress of the test1 and do not let it be obscured by devoting too close attention to matters of minor importance4 ,whatever the object of the test may be1 accuracy and reliability must underlie the work from beginning to end4 ,if questions of fulfillment of contract are involved1 there should be a clear understanding between all the parties1 preferably in writing1 as to the operating conditions which should obtain during the trial1 and as to the methods of testing to be followed1 unless these are already expressed in the contract itself4 ,among the many objects of performance tests1 the following may be noted3 ,determination of capacity and efficiency1 and how these compare with standard or guaranteed results4 ,comparison of different conditions or methods of operation4 ,determination of the cause of either inferior or superior results4 ,comparison of different kinds of fuel4 ,determination of the effect of changes of design or proportion upon capacity or efficiency1 etc4 #b4 ,,preparations 7,a7 ,dimensions3 ,measure the dimensions of the principal parts of the apparatus to be tested1 so far as they bear on the objects in view1 or determine these from correct working drawings4 ,notice the general features of the same1 both exterior and interior1 and make sketches1 if needed1 to show unusual points of design4 ,the dimensions of the heating surfaces of boilers and superheaters to be found are those of surfaces in contact with the fire or hot gases4 ,the submerged surfaces in boilers at the mean water level should be considered as water-heating surfaces1 and other surfaces which are exposed to the gases as superheating surfaces4 7,b7 ,examination of ,plant3 ,make a thorough examination of the physical condition of all parts of the plant or apparatus which concern the object in view1 and record the conditions found1 together with any points in the matter of operation which bear thereon4 ,in boilers1 examine for leakage of tubes and riveted or other metal joints4 ,note the condition of brick furnaces1 grates and baffles4 ,examine brick walls and cleaning doors for air leaks1 either by shutting the damper and observing the escaping smoke or by candle-flame test4 ,determine the condition of heating surfaces with reference to exterior deposits of soot and interior deposits of mud or scale4 ,see that the steam main is so arranged that condensed and entrained water cannot flow back into the boiler4 ,if the object of the test is to determine the highest efficiency or capacity obtainable1 any physical defects1 or defects of operation1 tending to make the result unfavorable should first be remedied2 all foul parts being cleaned1 and the whole put in first-class condition4 ,if1 on the other hand1 the object is to ascertain the performance under existing conditions1 no such preparation is either required or desired4 7,c7 ,general ,precautions against ,leakage3 ,in steam tests make sure that there is no leakage through blow-offs1 drips1 etc41 or any steam or water connections of the plant or apparatus undergoing test1 which would in any way affect the results4 ,all such connections should be blanked off1 or satisfactory assurance should be obtained that there is leakage neither out nor in4 ,this is a most important matter1 and no assurance should be considered satisfactory unless it is susceptible of absolute demonstration4 #c4 ,,fuel ,determine the character of fuel to be used4#fb ,for tests of maximum efficiency or capacity of the boiler to compare with other boilers1 the coal should be of some kind which is commercially regarded as a standard for the locality where the test is made4 ,in the ,eastern ,states the standards thus regarded for semi-bituminous coals are ,pocahontas 7,va4 and ,w4 ,va47 and ,new ,river 7,w4 ,va472 for anthracite coals those of the ,no4 #a buckwheat size1 fresh-mined1 containing not over #ac per cent ash by analysis2 and for bituminous coals1 ,youghiogheny and ,pittsburgh coals4 ,in some sections east of the ,allegheny ,mountains the semi-bituminous ,clearfield 7,pa47 and ,cumberland 7,md47 are also considered as standards4 ,these coals when of good quality possess the essentials of excellence1 adaptability to various kinds of furnaces1 grates1 boilers1 and methods of firing required1 besides being widely distributed and generally accessible in the ,eastern market4 ,there are no special grades of coal mined in the ,western ,states which are widely and generally considered as standards for testing purposes2 the best coal obtainable in any particular locality being regarded as the standard of comparison4 ,a coal selected for maximum efficiency and capacity tests1 should be the best of its class1 and especially free from slagging and unusual clinker-forming impurities4 ,for guarantee and other tests with a specified coal containing not more than a certain amount of ash and moisture1 the coal selected should not be higher in ash and in moisture than the stated amounts1 because any increase is liable to reduce the efficiency and capacity more than the equivalent proportion of such increase4 ,the size of the coal1 especially where it is of the anthracite class1 should be determined by screening a suitable sample4 #d4 ,,apparatus ,,and ,,instruments#fc ,the apparatus and instruments required for boiler tests are3 7,a7 ,platform scales for weighing coal and ashes4 7,b7 ,graduated scales attached to the water glasses4 7,c7 ,tanks and platform scales for weighing water 7or water meters calibrated in place74 ,wherever practicable the feed water should be weighed1 especially for guarantee tests4 ,the most satisfactory and reliable apparatus for this purpose consists of one or more tanks each placed on platform scales1 these being elevated a sufficient distance above the floor to empty into a receiving tank placed below1 the latter being connected to the feed pump4 ,where only one weighing tank is used the receiving tank should be of larger size than the weighing tank1 to afford sufficient reserve supply to the pump while the upper tank is filling4 ,if a single weighing tank is used it should preferably be of such capacity as to require emptying not oftener than every #e minutes4 ,if two or more are used the intervals between successive emptyings should not be less than #c minutes4 7,d7 ,pressure gauges1 thermometers1 and draft gauges4 7,e7 ,calorimeters for determining the calorific value of fuel and the quality of steam4 7,f7 ,furnaces pyrometers4 7,g7 ,gas analyzing apparatus4 #e4 ,,operating ,,conditions ,determine what the operating conditions and method of firing should be to conform to the object in view1 and see that they prevail throughout the trial1 as nearly as possible4 ,where uniformity in the rate of evaporation is required1 arrangement can be usually made to dispose of the steam so that this result can be attained4 ,in a single boiler it may be accomplished by discharging steam through a waste pipe and regulating the amount by means of a valve4 ,in a battery of boilers1 in which only one is tested1 the draft may be regulated on the remaining boilers to meet the varying demands for steam1 leaving the test boiler to work under a steady rate of evaporation4 #f4 ,,duration ,the duration of tests to determine the efficiency of a hand-fired boiler1 should be #aj hours of continuous running1 or such time as may be required to burn a total of #bej pounds of coal per square foot of grate4 ,in the case of a boiler using a mechanical stoker1 the duration1 where practicable1 should be at least #bd hours4 ,if the stoker is of a type that permits the quantity and condition of the fuel bed at beginning and end of the test to be accurately estimated1 the duration may be reduced to #aj hours1 or such time as may be required to burn the above noted total of #bej pounds per square foot4 ,in commercial tests where the service requires continuous operation night and day1 with frequent shifts of firemen1 the duration of the test1 whether the boilers are hand fired or stoker fired1 should be at least #bd hours4 ,likewise in commercial tests1 either of a single boiler or of a plant of several boilers1 which operate regularly a certain number of hours and during the balance of the day the fires are banked1 the duration should not be less than #bd hours4 ,the duration of tests to determine the maximum evaporative capacity of a boiler1 without determining the efficiency1 should not be less than #c hours4 #g4 ,,starting ,,and ,,stopping ,the conditions regarding the temperature of the furnace and boiler1 the quantity and quality of the live coal and ash on the grates1 the water level1 and the steam pressure1 should be as nearly as possible the same at the end as at the beginning of the test4 ,to secure the desired equality of conditions with hand-fired boilers1 the following method should be employed3 ,the furnace being well heated by a preliminary run1 burn the fire low1 and thoroughly clean it1 leaving enough live coal spread evenly over the grate 7say #b to #d inches71#fd to serve as a foundation for the new fire4 ,note quickly the thickness of the coal bed as nearly as it can be estimated or measured2 also the water level1#fe the steam pressure1 and the time1 and record the latter as the starting time4 ,fresh coal should then be fired from that weighed for the test1 the ashpit throughly cleaned1 and the regular work of the test proceeded with4 ,before the end of the test the fire should again be burned low and cleaned in such a manner as to leave the same amount of live coal on the grate as at the start4 ,when this condition is reached1 observe quickly the water level1#fe the steam pressure1 and the time1 and record the latter as the stopping time4 ,if the water level is not the same as at the beginning a correction should be made by computation1 rather than by feeding additional water after the final readings are taken4 ,finally remove the ashes and refuse from the ashpit4 ,in a plant containing several boilers where it is not practicable to clean them simultaneously1 the fires should be cleaned one after the other as rapidly as may be1 and each one after cleaning charged with enough coal to maintain a thin fire in good working condition4 ,after the last fire is cleaned and in working condition1 burn all the fires low 7say #d to #f inches71 note quickly the thickness of each1 also the water levels1 steam pressure1 and time1 which last is taken as the starting time4 ,likewise when the time arrives for closing the test1 the fires should be quickly cleaned one by one1 and when this work is completed they should all be burned low the same as the start1 and the various observations made as noted4 ,in the case of a large boiler having several furnace doors requiring the fire to be cleaned in sections one after the other1 the above directions pertaining to starting and stopping in a plant of several boilers may be followed4 ,to obtain the desired equality of conditions of the fire when a mechanical stoker other than a chain grate is used1 the procedure should be modified where practicable as follows3 ,regulate the coal feed so as to burn the fire to the low condition required for cleaning4 ,shut off the coal-feeding mechanism and fill the hoppers level full4 ,clean the ash or dump plate1 note quickly the depth and condition of the coal on the grate1 the water level1#ff the steam pressure1 and the time1 and record the latter as the starting time4 ,then start the coal-feeding mechanism1 clean the ashpit1 and proceed with the regular work of the test4 ,when the time arrives for the close of the test1 shut off the coal-feeding mechanism1 fill the hoppers and burn the fire to the same low point as at the beginning4 ,when this condition is reached1 note the water level1 the steam pressure1 and the time1 and record the latter as the stopping time4 ,finally clean the ashplate and haul the ashes4 ,in the case of chain grate stokers1 the desired operating conditions should be maintained for half an hour before starting a test and for a like period before its close1 the height of the throat plate and the speed of the grate being the same during both of these periods4 #h4 ,,records ,a log of the data should be entered in notebooks or on blank sheets suitably prepared in advance4 ,this should be done in such manner that the test may be divided into hourly periods1 or if necessary1 periods of less duration1 and the leading data obtained for any one or more periods as desired1 thereby showing the degree of uniformity obtained4 ,half-hourly readings of the instruments are usually sufficient4 ,if there are sudden and wide fluctuations1 the readings in such cases should be taken every #ae minutes1 and in some instances oftener4 ,the coal should be weighed and delivered to the firemen in portions sufficient for one hour's run1 thereby ascertaining the degree of uniformity of firing4 ,an ample supply of coal should be maintained at all times1 but the quantity on the floor at the end of each hour should be as small as practicable1 so that the same may be readily estimated and deducted from the total weight4 ,the records should be such as to ascertain also the consumption of feed water each hour and thereby determine the degree of uniformity of evaporation4 #i4 ,,quality ,,of ,,steam#fg ,if the boiler does not produce superheated steam the percentage of moisture in the steam should be determined by the use of a throttling or separating calorimeter4 ,if the boiler has superheating surface1 the temperature of the steam should be determined by the use of a thermometer inserted in a thermometer well4 ,for saturated steam construct a sampling pipe or nozzle made of one-half inch iron pipe and insert it in the steam main at a point where the entrained moisture is likely to be most thoroughly mixed4 ,the inner end of the pipe1 which should extend nearly across to the opposite side of the main1 should be closed and interior portion perforated with not less than twenty one-eighth inch holes equally distributed from end to end and preferably drilled in irregular or spiral rows1 with the first hole not less than half an inch from the wall of the pipe4 ,the sampling pipe should not be placed near a point where water may pocket or where such water may effect the amount of moisture contained in the sample4 ,where non-return valves are used1 or there are horizontal connections leading from the boiler to a vertical outlet1 water may collect at the lower end of the uptake pipe and be blown upward in a spray which will not be carried away by the steam owing to a lack of velocity4 ,a sample taken from the lower part of this pipe will show a greater amount of moisture than a true sample4 ,with goose-neck connections a small amount of water may collect on the bottom of the pipe near the upper end where the inclination is such that the tendency to flow backward is ordinarily counterbalanced by the flow of steam forward over its surface2 but when the velocity momentarily decreases the water flows back to the lower end of the goose-neck and increases the moisture at that point1 making it an undesirable location for sampling4 ,in any case it must be borne in mind that with low velocities the tendency is for drops of entrained water to settle to the bottom of the pipe1 and to be temporarily broken up into spray whenever an abrupt bend or other disturbance is met4 ,if it is necessary to attach the sampling nozzle at a point near the end of a long horizontal run1 a drip pipe should be provided a short distance in front of the nozzle1 preferably at a pocket formed by some fitting and the water running along the bottom of the main drawn off1 weighed1 and added to the moisture shown by the calorimeter2 or1 better1 a steam separator should be installed at the point noted4 ,in testing a stationary boiler the sampling pipe should be located as near as practicable to the boiler1 and the same is true as regards the thermometer well when the steam is superheated4 ,in an engine or turbine test these locations should be as near as practicable to throttle valve4 ,in the test of a plant where it is desired to get complete information1 especially where the steam main is unusually long1 sampling nozzles or thermometer wells should be provided at both points1 so as to obtain data at either point as may be required4 #aj4 ,,sampling ,,and ,,drying ,,coal ,during the progress of test the coal should be regularly sampled for the purpose of analysis and determination of moisture4 ,select a representative shovelful from each barrow-load as it is drawn from the coal pile or other source of supply1 and store the samples in a cool place in a covered metal receptacle4 ,when all the coal has thus been sampled1 break up the lumps1 thoroughly mix the whole quantity1 and finally reduce it by the process of repeated quartering and crushing to a sample weighing about #e pounds1 the largest pieces being about the size of a pea4 ,from this sample two one-quart air-tight glass fruit jars1 or other air-tight vessels1 are to be promptly filled and preserved for subsequent determinations of moisture1 calorific value1 and chemical composition4 ,these operations should be conducted where the air is cool and free from drafts4 ,illustration3 #cdfj ,horse-power ,installation of ,babcock ,wilcox ,boilers at the ,chicago1 ,ill41 ,shops of the ,chicago and ,northwestern ,ry4 ,co4 ,when the sample lot of coal has been reduced by quartering to1 say1 #ajj pounds1 a portion weighing1 say1 #ae to #bj pounds should be withdrawn for the purpose of immediate moisture determination4 ,this is placed in a shallow iron pan and dried on the hot iron boiler flue for at least #ab hours1 being weighed before and after drying on scales reading to quarter ounces4 ,the moisture thus determined is approximately reliable for anthracite and semi-bituminous coals1 but not for coals containing much inherent moisture4 ,for such coals1 and for all absolutely reliable determinations the method to be pursued is as follows3 ,take one of the samples contained in the glass jars1 and subject it to a thorough air drying1 by spreading it in a thin layer and exposing it for several hours to the atmosphere of a warm room1 weighing it before and after1 thereby determining the quantity of surface moisture it contains4#fh ,then crush the whole of it by running it through an ordinary coffee mill or other suitable crusher adjusted so as to produce somewhat coarse grains 7less than #a_/af inch71 thoroughly mix the crushed sample1 select from it a portion of from #aj to #ej grams1#fi weigh it in a balance which will easily show a variation as small as #a part in #ajjj1 and dry it for one hour in an air or sand bath at a temperature between #bdj and #bhj degrees ,fahrenheit4 ,weigh it and record the loss1 then heat and weigh again until the minimum weight has been reached4 ,the difference between the original and the minimum weight is the moisture in the air-dried coal4 ,the sum of the moisture thus found and that of the surface moisture is the total moisture4 #aa4 ,,ashes ,,and ,,refuse ,the ashes and refuse withdrawn from the furnace and ashpit during the progress of the test and at its close should be weighed so far as possible in a dry state4 ,if wet the amount of moisture should be ascertained and allowed for1 a sample being taken and dried for this purpose4 ,this sample may serve also for analysis and the determination of unburned carbon and fusing temperature4 ,the method above described for sampling coal may also be followed for obtaining a sample of the ashes and refuse4 #ab4 ,,calorific ,,tests ,,and ,,analyses ,,of ,,coal ,the quality of the fuel should be determined by calorific tests and analysis of the coal sample above referred to4#gj #ac4 ,,analyses ,,of ,,flue ,,gases ,for approximate determinations of the composition of the flue gases1 the ,orsat apparatus1 or some modification thereof1 should be employed4 ,if momentary samples are obtained the analyses should be made as frequently as possible1 say1 every #ae to #cj minutes1 depending on the skill of the operator1 noting at the time the sample is drawn the furnace and firing conditions4 ,if the sample drawn is a continuous one1 the intervals may be made longer4 #ad4 ,,smoke ,,observations#ga ,in tests of bituminous coals requiring a determination of the amount of smoke produced1 observations should be made regularly throughout the trial at intervals of #e minutes 7or if necessary every minute71 noting at the same time the furnace and firing conditions4 #ae4 ,,calculation ,,of ,,results ,the methods to be followed in expressing and calculating those results which are not self-evident are explained as follows3 7,a7 ,efficiency4 ,the efficiency of boiler1 furnace and grate is the relation between the heat absorbed per pound of coal fired1 and the calorific value of one pound of coal4 ,the efficiency of boiler and furnace is the relation between the heat absorbed per pound of combustible burned1 and the calorific value of one pound of combustible4 ,this expression of efficiency furnishes a means for comparing one boiler and furnace with another1 when the losses of unburned coal due to grates1 cleanings1 etc41 are eliminated4 ,the combustible burned is determined by subtracting from the weight of coal supplied to the boiler1 the moisture in the coal1 the weight of ash and unburned coal withdrawn from the furnace and ashpit1 and the weight of dust1 soot1 and refuse1 if any1 withdrawn from the tubes1 flues1 and combustion chambers1 including ash carried away in the gases1 if any1 determined from the analysis of coal and ash4 ,the combustible used for determining the calorific value is the weight of coal less the moisture and ash found by analysis4 ,the heat absorbed per pound of coal1 or combustible1 is calculated by multiplying the equivalent evaporation from and at #bab degrees per pound of coal or combustible by #igj4d4 ,other items in this section which have been treated elsewhere are3 7,b7 ,corrections for moisture in steam4 7,c7 ,correction for live steam used4 7,d7 ,equivalent evaporation4 7,e7 ,heat balance4 7,f7 ,total heat of combustion of coal4 7,g7 ,air for combustion and the methods recommended for calculating these results are in accordance with those described in different portions of this book4 #af4 ,,data ,,and ,,results ,the data and results should be reported in accordance with either the short form or the complete form1 adding lines for data not provided for1 or omitting those not required1 as may conform to the object in view4 #ag4 ,,chart ,in trials having for an object the determination and exposition of the complete boiler performance1 the entire log of readings and data should be plotted on a chart and represented graphically4 #ah4 ,,tests ,,with ,,oil ,,and ,,gas ,,fuels ,tests of boilers using oil or gas for fuel should accord with the rules here given1 excepting as they are varied to conform to the particular characteristics of the fuel4 ,the duration in such cases may be reduced1 and the flying method of starting and stopping employed4 ,the table of data and results should contain items stating character of furnace and burner1 quality and composition of oil or gas1 temperature of oil1 pressure of steam used for vaporizing and quantity of steam used for both vaporizing and for heating4 ,,table ,,data ,,and ,,results ,,of ,,evaporative ,,test ,,short ,,form1 ,,code ,,of #aiab #a ,test of44444444444444444boiler located at44444444444444444444444444444444 to determine444444444444444conducted by444444444444444444444444444444 #b ,kind of furnace444444444444444444444444444444444 4444444444444444444444444 #c ,grate surface444444444444444444444444444444444 4444444444444444square feet #d ,water-heating surface444444444444444444444444444444444 44444444square feet #e ,superheating surface444444444444444444444444444444444 444444444square feet #f ,date44444444444444444444444444444444444 4444444444444444444444444444444444 #g ,duration4444444444444444444444444444444 44444444444444444444444444444hours #h ,kind and size of coal444444444444444444444444444444444444 4444444444444444 ,,average ,,pressures1 ,,temperatures1 ,,etc4 #i ,steam pressure by gauge44444444444444444444444444444444444 444444444pounds #aj ,temperature of feed water entering boiler4444444444444444444444444degrees #aa ,temperature of escaping gases leaving boiler4444444444444444444444degrees #ab ,force of draft between damper and boiler444444444444444444444444444inches #ac ,percentage of moisture in steam1 or number degrees of superheating444444444444444444per cent or degrees ,,total ,,quantities #ad ,weight of coal as fired#gb44444444444444444444444444444444 44444444pounds #ae ,percentage of moisture in coal44444444444444444444444444444444444p er cent #af ,total weight of dry coal consumed44444444444444444444444444444444 44pounds #ag ,total ash and refuse4444444444444444444444444444444444 4444444444444pounds #ah ,percentage of ash and refuse in dry coal4444444444444444444444444per cent #ai ,total weight of water fed to the boiler#gc444444444444444444444444pounds #bj ,total water evaporated1 corrected for moisture in steam444444444444pounds #ba ,total equivalent evaporation from and at #bab degrees444444444444444pounds ,,hourly ,,quantities ,,and ,,rates #bb ,dry coal consumed per hour444444444444444444444444444444444444 44444pounds #bc ,dry coal per square feet of grate surface per hour44444444444444444pounds #bd ,water evaporated per hour corrected for quality of steam44444444444pounds #be ,equivalent evaporation per hour from and at #bab degrees444444444444pounds #bf ,equivalent evaporation per hour from and at #bab degrees per square foot of water-heating surface444444444444444444444444pounds ,,capacity #bg ,evaporation per hour from and at #bab degrees 7same as ,line #be744444pounds #bh ,boiler horse power developed 7,item #bgcd74444444444444;boiler horse power #bi ,rated capacity1 in evaporation from and at #bab degrees per hour4444pounds #cj ,rated boiler horse power4444444444444444444444444444444boil er horse power #ca ,percentage of rated capacity developed444444444444444444444444444per cent ,,economy ,,results #cb ,water fed per pound of coal fired 7,item #ai;,item #ad74444444444444444pounds #cc ,water evaporated per pound of dry coal 7,item #bj;,item #af744444444444pounds #cd ,equivalent evaporation from and at #bab degrees per pound of dry coal 7,item #ba;,item #af744444444444444444444444444444444444p ounds #ce ,equivalent evaporation from and at #bab degrees per pound of combustible ,item #ba7;,item #af-;,item #ag74444444444444444444444pounds ,,efficiency #cf ,calorific value of one pound of dry coal4444444444444444444444444,b4 t4 u4 #cg ,calorific value of one pound of combustible4444444444444444444444,b4 t4 u4 7 ,item #cdigj4d7 #ch ,efficiency of boiler1 furnace and grate 7#ajj -------------74444per cent 7 ,item #cf 7 7 ,item #ceigj4d7 #ci ,efficiency of boiler and furnace 7#ajj -------------744444444444per cent 7 ,item #cg 7 ,,cost ,,of ,,evaporation #dj ,cost of coal per ton of444444pounds delivered in boiler room444444dollars #da ,cost of coal required for evaporating #ajjj pounds of water from and at #bab degrees444444444444444444444444444444444 4444444dollars ,illustration3 ,portion of #cfjj ,horse-power ,installation of ,babcock ,wilcox ,boilers1 ,equipped with ,babcock ,wilcox ,chain ,grate ,stokers at the ,loomis ,street ,plant of the ,peoples ,gas ,light ,coke ,co41 ,chicago1 ,ill4 ,this ,company has ,installed #gghj ,horse ,power of ,babcock ,wilcox ,boilers ,,the ,,selection ,,of ,,boilers ,,with ,a ,,consideration ,,of ,,the ,,factors ,,determining ,,such ,,selection ,the selection of steam boilers is a matter to which the most careful thought and attention may be well given4 ,within the last twenty years1 radical changes have taken place in the methods and appliances for the generation and distribution of power4 ,these changes have been made largely in the prime movers1 both as to type and size1 and are best illustrated by the changes in central station power-plant practice4 ,it is hardly within the scope of this work to treat of power-plant design and the discussion will be limited to a consideration of the boiler end of the power plant4 ,as stated1 the changes have been largely in prime movers1 the steam generating equipment having been considered more or less of a standard piece of apparatus whose sole function is the transfer of the heat liberated from the fuel by combustion to the steam stored or circulated in such apparatus4 ,when the fact is considered that the cost of steam generation is roughly from #fe to #hj per cent of the total cost of power production1 it may be readily understood that the most fruitful field for improvement exists in the boiler end of the power plant4 ,the efficiency of the plant as a whole will vary with the load it carries and it is in the boiler room where such variation is largest and most subject to control4 ,the improvements to be secured in the boiler room results are not simply a matter of dictation of operating methods4 ,the securing of perfect combustion1 with the accompanying efficiency of heat transfer1 while comparatively simple in theory1 is difficult to obtain in practical operation4 ,this fact is perhaps best exemplified by the difference between test results and those obtained in daily operation even under the most careful supervision4 ,this difference makes it necessary to establish a standard by which operating results may be judged1 a standard not necessarily that which might be possible under test conditions but one which experiment shows can be secured under the very best operating conditions4 ,the study of the theory of combustion1 draft1 etc41 as already given1 will indicate that the question of efficiency is largely a matter of proper relation between fuel1 furnace and generator4 ,while the possibility of a substantial saving through added efficiency cannot be overlooked1 the boiler design of the future must1 even more than in the past1 be considered particularly from the aspect of reliability and simplicity4 ,a flexibility of operation is necessary as a guarantee of continuity of service4 ,in view of the above1 before the question of the selection of boilers can be taken up intelligently1 it is necessary to consider the subjects of boiler efficiency and boiler capacity1 together with their relation to each other4 ,the criterion by which the efficiency of a boiler plant is to be judged is the cost of the production of a definite amount of steam4 ,considered in this sense1 there must be included in the efficiency of a boiler plant the simplicity of operation1 flexibility and reliability of the boiler used4 ,the items of repair and upkeep cost are often high because of the nature of the service4 ,the governing factor in these items is unquestionably the type of boiler selected4 ,the features entering into the plant efficiency are so numerous that it is impossible to make a statement as to a means of securing the highest efficiency which will apply to all cases4 ,such efficiency is to be secured by the proper relation of fuel1 furnace and boiler heating surface1 actual operating conditions1 which allow the approaching of the potential efficiencies made possible by the refinement of design1 and a systematic supervision of the operation assisted by a detailed record of performances and conditions4 ,the question of supervision will be taken up later in the chapter on ,operation and ,care of ,boilers4 ,the efficiencies that may be expected from the combination of well-designed boilers and furnaces are indicated in ,table #ei in which are given a number of tests with various fuels and under widely different operating conditions4 ,it is to be appreciated that the results obtained as given in this table are practically all under test conditions4 ,the nearness with which practical operating conditions can approach these figures will depend upon the character of the supervision of the boiler room and the intelligence of the operating crew4 ,the size of the plant will ordinarily govern the expense warranted in securing the right sort of supervision4 ,the bearing that the type of boiler has on the efficiency to be expected can only be realized from a study of the foregoing chapters4 ,capacity--,capacity1 as already defined1 is the ability of a definite amount of boiler-heating surface to generate steam4 ,boilers are ordinarily purchased under a manufacturer's specification1 which rates a boiler at a nominal rated horse power1 usually based on #aj square feet of heating surface per horse power4 ,such a builders' rating is absolutely arbitrary and implies nothing as to the limiting amount of water that this amount of heating surface will evaporate4 ,it does not imply that the evaporation of #cd4e pounds of water from and at #bab degrees with #aj square feet of heating surface is the limit of the capacity of the boiler4 ,further1 from a statement that a boiler is of a certain horse power on the manufacturer's basis1 it is not to be understood that the boiler is in any state of strain when developing more than its rated capacity4 ,broadly stated1 the evaporative capacity of a certain amount of heating surface in a well-designed boiler1 that is1 the boiler horse power it is capable of producing1 is limited only by the amount of fuel that can be burned under the boiler4 ,while such a statement would imply that the question of capacity to be secured was simply one of making an arrangement by which sufficient fuel could be burned under a definite amount of heating surface to generate the required amount of steam1 there are limiting features that must be weighed against the advantages of high capacity developed from small heating surfaces4 ,briefly stated1 these factors are as follows3 #ast4 ,efficiency4 ,as the capacity increases1 there will in general be a decrease in efficiency1 this loss above a certain point making it inadvisable to try to secure more than a definite horse power from a given boiler4 ,this loss of efficiency with increased capacity is treated below in detail1 in considering the relation of efficiency to capacity4 #bnd4 ,grate ,ratio ,possible or ,practicable4 ,all fuels have a maximum rate of combustion1 beyond which satisfactory results cannot be obtained1 regardless of draft available or which may be secured by mechanical means4 ,such being the case1 it is evident that with this maximum combustion rate secured1 the only method of obtaining added capacity will be through the addition of grate surface4 ,there is obviously a point beyond which the grate surface for a given boiler cannot be increased4 ,this is due to the impracticability of handling grates above a certain maximum size1 to the enormous loss in draft pressure through a boiler resulting from an attempt to force an abnormal quantity of gas through the heating surface and to innumerable details of design and maintenance that would make such an arrangement wholly unfeasible4 #crd4 ,feed ,water4 ,the difficulties that may arise through the use of poor feed water or that are liable to happen through the use of practically any feed water have already been pointed out4 ,this question of feed is frequently the limiting factor in the capacity obtainable1 for with an increase in such capacity comes an added concentration of such ingredients in the feed water as will cause priming1 foaming or rapid scale formation4 ,certain waters which will give no trouble that cannot be readily overcome with the boiler run at ordinary ratings will cause difficulties at higher ratings entirely out of proportion to any advantage secured by an increase in the power that a definite amount of heating surface may be made to produce4 ,where capacity in the sense of overload is desired1 the type of boiler selected will play a large part in the successful operation through such periods4 ,a boiler must be selected with which there is possible a furnace arrangement that will give flexibility without undue loss in efficiency over the range of capacity desired4 ,the heating surface must be so arranged that it will be possible to install in a practical manner1 sufficient grate surface at or below the maximum combustion rate to develop the amount of power required4 ,the design of boiler must be such that there will be no priming or foaming at high overloads and that any added scale formation due to such overloads may be easily removed4 ,certain boilers which deliver commercially dry steam when operated at about their normal rated capacity will prime badly when run at overloads and this action may take place with a water that should be easily handled by a properly designed boiler at any reasonable load4 ,such action is ordinarily produced by the lack of a well defined1 positive circulation4 ,relation of ,efficiency and ,capacity--,the statement has been made that in general the efficiency of a boiler will decrease as the capacity is increased4 ,considering the boiler alone1 apart from the furnace1 this statement may be readily explained4 ,presupposing a constant furnace temperature1 regardless of the capacity at which a given boiler is run2 to assure equal efficiencies at low and high ratings1 the exit temperature in the two instances would necessarily be the same4 ,for this temperature at the high rating1 to be identical with that at the low rating1 the rate of heat transfer from the gases to the heating surfaces would have to vary directly as the weight or volume of such gases4 ,experiment has shown1 however1 that this is not true but that this rate of transfer varies as some power of the volume of gas less than one4 ,as the heat transfer does not1 therefore1 increase proportionately with the volume of gases1 the exit temperature for a given furnace temperature will be increased as the volume of gases increases4 ,as this is the measure of the efficiency of the heating surface1 the boiler efficiency will1 therefore1 decrease as the volume of gases increases or the capacity at which the boiler is operated increases4 ,further1 a certain portion of the heat absorbed by the heating surface is through direct radiation from the fire4 ,again1 presupposing a constant furnace temperature2 the heat absorbed through radiation is solely a function of the amount of surface exposed to such radiation4 ,hence1 for the conditions assumed1 the amount of heat absorbed by radiation at the higher ratings will be the same as at the lower ratings but in proportion to the total absorption will be less4 ,as the added volume of gas does not increase the rate of heat transfer1 there are therefore two factors acting toward the decrease in the efficiency of a boiler with an increase in the capacity4 ,,table #ei ,,tests ,,of ,,babcock ,,wilcox ,,boilers ,,with ,,various ,,fuels ,number ,rated of ,name and ,location ,kind of ,coal ,kind of ,horse ,test of ,plant ,furnace ,power of ,boiler ,susquehanna ,coal ,co41 ,no4 #a ,anthracite,hand #a ,shenandoah1 ,pa4 ,buckwheat ,fired #cjj ,balbach ,smelting ,no4 #b ,buckwheat ,wilkenson #b ,refining ,co41 ,newark1 ,n4 ,j4and ,bird's-eye ,stoker #bah ,h4 ,r4 ,worthington1 ,no4 #b ,anthracite,hand #c ,harrison ,n4 ,j4 ,buckwheat ,fired #cjj ,raymond ,street ,jail1 ,anthracite ,pea ,hand #d ,brooklyn1 ,n4 ,y4 ,fired #aee ,r4 ,h4 ,macy ,co41 ,no4 #c ,anthracite,hand #e ,new ,york1 ,n4 ,y4 ,buckwheat ,fired #bic ,national ,bureau of ,anthracite ,egg ,hand #f ,standards1 ,washington1 ,d4,c4 ,fired #aai ,fred4 ,loeser ,co41 ,no4 #a ,anthracite,hand #g ,brooklyn1 ,n4 ,y4 ,buckwheat ,fired #cjj ,new ,york ,edison ,co41 ,no4 #b ,anthracite,hand #h ,new ,york ,city ,buckwheat ,fired #cgd ,sewage ,pumping ,station1 ,hocking ,valley ,hand #i ,cleveland1 ,o4 ,lump1 ,o4 ,fired #aej ,scioto ,river ,pumping ,sta41 ,hocking ,valley1 ,hand #aj ,cleveland1 ,o4 ,o4 ,fired #cjj ,consolidated ,gas ,electric,somerset1 ,pa4 ,hand #aa ,co41 ,baltimore1 ,md4 ,fired #fdj ,consolidated ,gas ,electric,somerset1 ,pa4 ,hand #ab ,co41 ,baltimore1 ,md4 ,fired #fdj ,merrimac ,mfg4 ,co41 ,georges ,creek1 ,hand #ac ,lowell1 ,mass4 ,md4 ,fired #cba ,great ,west'n ,sugar ,co41 ,lafayette1 ,col41,hand,fired #ad ,ft4 ,collins1 ,col4 ,mine ,run ,extension #cea ,baltimore ,sewage ,pumping ,new ,river ,hand #ae ,station ,fired #bff ,tennessee ,state ,prison1 ,brushy ,mountain1,hand #af ,nashville1 ,tenn4 ,tenn4 ,fired #cjj ,pine ,bluff ,corporation1 ,arkansas ,slack ,hand #ag ,pine ,bluff1 ,ark4 ,fired #bih ,pub4 ,serv4 ,corporation ,valley1 ,pa41 ,roney #ah of ,n4 ,j41 ,hoboken ,mine ,run ,stoker #ebj ,pub4 ,serv4 ,corporation ,valley1 ,pa41 ,roney #ai of ,n4 ,j41 ,hoboken ,mine ,run ,stoker #ebj ,frick ,building1 ,pittsburgh ,nut ,american #bj ,pittsburgh1 ,pa4 and ,slack ,stoker #cjj ,new ,york ,edison ,co41 ,loyal ,hanna1 ,pa4,taylor #ba ,new ,york ,city ,stoker #fjd ,city of ,columbus1 ,o41 ,hocking ,valley1 ,detroit #bb ,dept4 ,lighting ,o4 ,stoker #cjj ,edison ,elec4 ,illum4 ,co41 ,new ,river ,murphy #bc ,boston1 ,mass4 ,stoker #ejh ,colorado ,springs ,pike ,view1 ,col41,green ,chn #bd ,interurban ,ry41 ,col4 ,mine ,run ,grate #djj ,pub4 ,serv4 ,corporation ,lancashire1 ,pa4 ,b,w4,chain #be of ,n4 ,j41 ,marion ,grate #fjj ,pub4 ,serv4 ,corporation ,lancashire1 ,pa4 ,b,w4,chain #bf of ,n4 ,j41 ,marion ,grate #fjj ,erie ,county ,electric ,co41 ,mercer ,county1 ,b,w4,chain #bg ,erie1 ,pa4 ,pa4 ,grate #ejh ,union ,elec4 ,lt4 ,pr4 ,co41 ,mascouth1 ,ill4 ,b,w4,chain #bh ,st4 ,louis1 ,mo4 ,grate #ejh ,union ,elec4 ,lt4 ,pr4 ,co41 ,st4 ,clair ,b,w4,chain #bi ,st4 ,louis1 ,mo4 ,county1 ,ill4 ,grate #ejh ,commonwealth ,edison ,co41 ,carterville1 ,b,w4,chain #cj ,chicago1 ,ill4 ,ill41 ,screenings,grate #ejh ,number,grate ,dura-,steam ,temper-,degrees,factor ,draft of ,surf4 tion,pres4 ature ,super of ,in ,at ,test ,square,test ,by ,water -heat ,evapo-,furnace,boiler ,feet ,hours,gauge ,degrees,degreesration,inches ,damper ,pounds ,fahr4 ,fahr4 ,upr_/,lwr,inches #a #hd #h #fh #ec4i #a4aife 4#da 4#ba 4#fe #b #ea4f #g #acf4c #bjc #aej #a4adhj 4#dg 4#ef #c #fg4f #h #aci #aci4f #aci #a4aihd 4#gj 4#if #d #dj #h #aaj4b #acg #a4aahe 4#cc 4#dc #e #ei4e #aj #acc4b #ge4b #a4ahdi 4#ai 4#dj #f #bf4e #ah #acb4a #gj4e #a4ahig 4#cc 4#ea #g #dh4i #g #aja4 #aba4c #a4accc -4#bj 4#cj #h #ei4e #f #aia4h #hh4c #a4agga 4#ej #i #bg #bd #aef4c #eh #a4bjea 4#aj 4#bd #aj #bd #ade #ge #a4ahff 4#bf 4#df #aa #aah #h #agj #ahf4a #ff4g #a4aafb 4#cd 4#db #ab #aah #g4ib #agc #ahj4b #ge4b #a4abgf 4#dd 4#eh #ac #eb #bd #ge #ec4c #a4aihg 4#be 4#ce #ad #ei4e #h #aje #ce4h #a4bbai 4#ag 4#ch #ae #ei4e #bd #agj4a #acc #a4abic 4#ab 4#dc #af #ea4c #aj #aje #ge4a #a4ahad 4#ba 4#db #ag #ei4e #h #adi4b #ga #a4aiaj 4#ce 4#ei #ah #ajc4b #aj #acc4b #fe4c #fe4i #a4bcdf 4#je 4#di #ai #ajc4b #i #aci #fd #hj4b #a4bceh 4#ah 4#eg #bj #ec #i #abe #gf4f #a4ahbf #a4fd 4#fd #ba #ge #h #aih4e #afe4a #ajd #a4affb #c4je 4#fj #bb #i #adj #fg #ahj #a4bidb 4#bb 4#ce #bc #ij #af4be #aii #dh4d #acf4e #a4biif 4#bc #a4bg #bd #ajc #h #abi #ef #a4bjjb 4#bc 4#cj 4#eb #be #acb #h #bjj #eg4b #bhj4d #a4ciji 4#ai 4#eb 4#ae #bf #acb #h #aii #fj4g #aga4j #a4caia 4#jd 4#eb #bg #ij #h #abj #fi4i #a4ahhh 4#ca 4#eh #bh #ajc4e #h #ahj #df #aac #a4bhga 4#fb #a4bd #bi #ajc4e #h #ahc #ec4a #ajd #a4bgbe 4#fj #a4bf #cj #ij #g #ahd #abg4a #ahj #a4bcic 4#fh #a4ae ,number,temper- ,coal of ature ,total ,moist- ,total ,ash and ,total ,dry,coal ,test ,flue,gas,weight3 ure dry ,refuse,combus-_/sq4ft4 ,degrees ,fired ,per ,coal ,per tible ,grate ,fahr4 ,pounds ,cent ,pounds ,cent ,pounds_/,hr4,lb4 #a #aafgj #d4de #aaaea #bf4je #hbdh #af4f #b #dhg #hhjj #g4fb #habi #bi4hb #egje #ai4ga #c #eei #ajgii #f4db #ajajf #bj4jb #hjha #ba4gg #d #dbg #ejhh #d4jj #dhhd #ai4ce #cici #ae4bf #e #dad #iddj #b4ad #ibch #aa4ai #hbjd #ae4eb #f #daj #heee #c4fb #hbde #ae4gc #fidh #ag4bh #g #dhj #gacj #g4ch #ffjd #ah4ce #ecib #ai4bi #h #ddi #gejj #b4gj #gbih #bg4id #ebei #ad4gc #i #daj #aejhg #g4ej #acief #aa4cj #abcgi #ba4e #aj #ejc #biebh #g4gb #bgbdh #bd4g #aa #dhg #bjdjj #b4hd #aihba #g4hc #ahbfi #ba4jj #ab #did #baccb #b4bi #bjhdc #h4bc #aiabg #bb4ca #ac #eaf #bdehd #d4bi #bcebi #g4fc #bahhc #ah4he #ad #ebc #aeedj #ah4fd #abfdc #bh4ei #ae #dgd #ahccj #b4jc #agieh #af4cf #afjif #ab4eg #af #ecf #abbdc #b4ad #aaiha #bc4dj #ag #ecd #ajejj #c4jd #ajaha #ba4dj #ah #deh #ahfjj #c4dj #agifh #ah4ch #adffe #ag4da #ai #fji #bcdjj #b4ef #bbhja #af4hi #ahiea #bd4ee #bj #eah #ajejj #a4hc #ajcjh #ab4bb #ijdh #ba4ef #ba #ecf #bebif #b4bj #bdgcf #da4j #bb #eaa #adbfc #h4fc #acjcb #bc #efj #cifgj #d4bb #cgiif #d4cb #cfcee #be4ih #bd #ech #bcjjj #bc4gc #agedb #ba4cf #be #eij #cbbje #d4jc #cjijg #ae4fe #bfjgj #bi4bf #bf #ebi #bdbdc #d4ji #bcbea #ab4cc #bjche #bb4ja #bg #ecc #bbcbh #d4db #bacda #af4hh #aggci #bi4fd #bh #ebc #cbafc #ac4gd #bggdd #cc4ej #bi #efg #cfaej #ad4fb #cjhfe #cg4bh #cj #cjfaj #aa4ab #bgbjf #ad4gj #bcaih #dc4bj ,number ,water ,flue ,gas ,analysis of ,actual ,equiv4ditto _/ ,rated,,co#b ,o ,,co ,test ,evapor-,evap4 sq4ft4 ,cap'ty4 ,per ,per ,per ation #bab ,heating,develpd ,cent ,cent ,cent _/,hr4,lb4_/,hr4,lb4,surface,per,cent #a #ajbfh #abbhf #d4aj #aah4g #b #hbdf #idff #d4cd #abe4g #c #iade #ajiei #c4fe #aje4i #d #ejjf #eeii #c4fa #ajd4g #ab4bf #g4hh #j4j #e #gdcd #hhji #c4jf #hg4b #f #bijc #cded #b4ia #hd4d #g #gdfd #hdei #b4hb #ha4g #h #iafd #ajghg #b4hh #hc4e #i #dcgd #ebga #c4ea #aja4h #aa4g #g4c #j4jg #aj #hfhh #ajcji #c4dd #ii4f #ab4i #e4j #j4b #aa #bdjcf #bfhbi #d4ai #aba4e #ab4e #f4d #j4e #ab #becac #bhedd #d4df #abi4c #ac4c #e4a #j4e #ac #iafh #ajiij #c4db #ii4c #i4f #h4h #j4d #ad #aabjb #acfhi #c4ia #aac4e #i4a #i4i #j4j #ae #gefe #hedc #c4ba #ic4a #aj4ga #i4aj #j4j #af #ieab #aabcg #c4gd #ajh4f #ag #ibeg #aajbe #c4gj #ajg4b #ah #aehhg #aifad #c4gg #ajh4g #aa4g #g4g #j4j #ai #bacbj #bfcdg #e4jf #adf4g #aa4i #g4h #j4j #bj #iigf #aaigh #c4ic #aab4j #aa4c #g4e #j4j #ba #bhdea #ccjff #e4dg #aeh4f #ab4c #f4d #j4g #bb #ajdfg #acebf #d4ea #acj4g #aa4i #g4b #j4jd #bc #bjgjj #bfijb #e4cj #aec4e #aa4a #bd #adfej #agehc #d4dj #abg4d #be #bhijf #djbje #f4gj #aid4b #aj4e #h4c #j4j #bf #bcjgd #cjdcg #e4jg #adg4j #aj4a #i4j #j4j #bg #bjgei #bdfgh #d4he #adj4h #aj4a #i4a #j4j #bh #baiih #bhcad #e4fg #afa4e #h4g #aj4f #j4j #bi #bdchf #cajca #f4aa #agg4a #h4i #aj4g #j4b #cj #cjeje #cghje #g4dc #bae4g #aj4d #i4d #j4b ,number ,proximate ,analysis ,dry ,coal ,equiv4,combnd4 of ,volatl4 ,fixed ,ash ,b4t4u4_/,evap4 ,efficy4 ,test ,matter ,carbon ,per ,pound #bab_/;,boiler ,per ,per ,cent ,dry ,pound ,grate ,cent ,cent ,coal ,dry,coal,per,cent #a #bf4je #aaiac #h4ha #ga4h #b #aaajd #h4ae #gb4a #c #e4ee #hj4fj #ac4hg #abcjj #h4fg #fh4d #d #g4gd #gg4dh #ad4gh #abhea #i4ag #fi4b #e #acach #i4ec #fi4f #f #f4ac #hd4hf #i4ja #acded #i4eg #fi4j #g #abbbd #h4ig #ga4b #h #j4ee #hf4gc #ab4gb #abfdb #h4hg #fh4a #i #ci4ja #dh4jh #ab4ia #abbib #i4jf #ga4e #aj #ch4cc #df4ga #ad4if #abbhd #i4jh #ga4g #aa #ai4hf #gc4jb #g4ab #adfjb #aj4hc #gb4j #ab #bj4bd #gb4bf #g4ej #adcha #aj4hd #gc4b #ac #adiee #aa4ba #gb4g #ad #ci4fj #ed4df #e4id #aaehe #h4ff #gb4e #ae #ag4dd #gf4db #e4hd #aecgi #aa4db #gb4a #af #cc4dj #ed4gc #aa4hg #abgea #i4ch #ga4d #ag #ae4db #fb4dh #bb4aj #abjfj #h4ff #fi4f #ah #ad4ii #ge4ac #i4hh #adaeb #aj4ib #gd4hh #ai #ad4dj #gd4cc #aa4bg #adjbb #aj4dj #ga4ig #bj #cb4dd #ef4ga #aj4he #aceaj #aj4cj #gd4f #ba #ai4jb #gb4ji #h4hi #adaje #aj4fi #gc4e #bb #cb4aa #ec4ic #ac4if #abdce #i4da #gc4d #bc #ai4ff #ge4da #d4ic #adiaj #aa4ea #gd4i #bd #dc4eg #df4bb #aj4ba #aaafj #h4jb #fi4g #be #bb4hd #fi4ia #g4be #achdj #aj4da #gb4f #bf #cb4cf #fj4fg #f4ig #adjbg #aj4dg #gb4a #bg #cc4bf #ed4jc #ab4ga #abgdb #i4be #gj4d #bh #bh4if #df4hh #bd4af #ajegf #h4af #gd4i #bi #cf4ej #da4bj #bb4cj #ajhdi #h4jd #ga4i #cj #aj4bd #acabf #i4gc #ga4i ,illustration3 #aedjj ,horse-power ,installation of ,babcock ,wilcox ,boilers and ,superheaters1 ,equipped with ,babcock ,wilcox ,chain ,grate ,stokers at the ,plant of the ,twin ,city ,rapid ,transit ,co41 ,minneapolis1 ,minn4 ,this increase in the efficiency of the boiler alone with the decrease in the rate at which it is operated1 will hold to a point where the radiation of heat from the boiler setting is proportionately large enough to be a governing factor in the total amount of heat absorbed4 ,the second reason given above for a decrease of boiler efficiency with increase of capacity1 viz41 the effect of radiant heat1 is to a greater extent than the first reason dependent upon a constant furnace temperature4 ,any increase in this temperature will affect enormously the amount of heat absorbed by radiation1 as this absorption will vary as the fourth power of the temperature of the radiating body4 ,in this way it is seen that but a slight increase in furnace temperature will be necessary to bring the proportional part1 due to absorption by radiation1 of the total heat absorbed1 up to its proper proportion at the higher ratings4 ,this factor of furnace temperature more properly belongs to the consideration of furnace efficiency than of boiler efficiency4 ,there is a point1 however1 in any furnace above which the combustion will be so poor as to actually reduce the furnace temperature and1 therefore1 the proportion of heat absorbed through radiation by a given amount of exposed heating surface4 ,since it is thus true that the efficiency of the boiler considered alone will increase with a decreased capacity1 it is evident that if the furnace conditions are constant regardless of the load1 that the combined efficiency of boiler and furnace will also decrease with increasing loads4 ,this fact was clearly proven in the tests of the boilers at the ,detroit ,edison ,company4#gd ,the furnace arrangement of these boilers and the great care with which the tests were run made it possible to secure uniformly good furnace conditions irrespective of load1 and here the maximum efficiency was obtained at a point somewhat less than the rated capacity of the boilers4 ,in some cases1 however1 and especially in the ordinary operation of the plant1 the furnace efficiency will1 up to a certain point1 increase with an increase in power4 ,this increase in furnace efficiency is ordinarily at a greater rate as the capacity increases than is the decrease in boiler efficiency1 with the result that the combined efficiency of boiler and furnace will to a certain point increase with an increase in capacity4 ,this makes the ordinary point of maximum combined efficiency somewhat above the rated capacity of the boiler and in many cases the combined efficiency will be practically a constant over a considerable range of ratings4 ,the features limiting the establishing of the point of maximum efficiency at a high rating are the same as those limiting the amount of grate surface that can be installed under a boiler4 ,the relative efficiency of different combinations of boilers and furnaces at different ratings depends so largely upon the furnace conditions that what might hold for one combination would not for another4 ,in view of the above1 it is impossible to make a statement of the efficiency at different capacities of a boiler and furnace which will hold for any and all conditions4 ,fig4 #dj shows in a general form the relation of efficiency to capacity4 ,this curve has been plotted from a great number of tests1 all of which were corrected to bring them to approximately the same conditions4 ,the curve represents test conditions4 ,the efficiencies represented are those which may be secured only under such conditions4 ,the general direction of the curve1 however1 will be found to hold approximately correct for operating conditions when used only as a guide to what may be expected4 ,graph3 ,combined ,efficiency of ,boiler and ,furnace ,per ,cent against ,per ,cent of ,boiler's ,rated ,capacity ,developed ,fig4 #dj4 ,approximate ,variation of ,efficiency with ,capacity under ,test ,conditions ,economical ,loads--,with the effect of capacity on economy in mind1 the question arises as to what constitutes the economical load to be carried4 ,in figuring on the economical load for an individual plant1 the broader economy is to be considered1 that in which1 against the boiler efficiency1 there is to be weighed the plant first cost1 returns on such investment1 fuel cost1 labor1 capacity1 etc41 etc4 ,this matter has been widely discussed1 but unfortunately such discussion has been largely limited to central power station practice4 ,the power generated in such stations1 while representing an enormous total1 is by no means the larger proportion of the total power generated throughout the country4 ,the factors determining the economic load for the small plant1 however1 are the same as in a large1 and in general the statements made relative to the question are equally applicable4 ,the economical rating at which a boiler plant should be run is dependent solely upon the load to be carried by that individual plant and the nature of such load4 ,the economical load for each individual plant can be determined only from the careful study of each individual set of conditions or by actual trial4 ,the controlling factor in the cost of the plant1 regardless of the nature of the load1 is the capacity to carry the maximum peak load that may be thrown on the plant under any conditions4 ,while load conditions1 do1 as stated1 vary in every individual plant1 in a broad sense all loads may be grouped in three classes3 #ast1 the approximately constant #bd-;hour load2 #bnd1 the steady #aj or #ab-;hour load usually with a noonday period of no load2 #crd1 the #bd-;hour variable load1 found in central station practice4 ,the economical load at which the boiler may be run will vary with these groups3 #ast4 ,for a constant load1 #bd hours in the day1 it will be found in most cases that1 when all features are considered1 the most economical load or that at which a given amount of steam can be produced the most cheaply will be considerably over the rated horse power of the boiler4 ,how much above the rated capacity this most economic load will be1 is dependent largely upon the cost of coal at the plant1 but under ordinary conditions1 the point of maximum economy will probably be found to be somewhere between #be and #ej per cent above the rated capacity of the boilers4 ,the capital investment must be weighed against the coal saving through increased thermal efficiency and the labor account1 which increases with the number of units1 must be given proper consideration4 ,when the question is considered in connection with a plant already installed1 the conditions are different from where a new plant is contemplated4 ,in an old plant1 where there are enough boilers to operate at low rates of capacity1 the capital investment leads to a fixed charge1 and it will be found that the most economical load at which boilers may be operated will be lower than where a new plant is under consideration4 #bnd4 ,for a load of #aj or #ab hours a day1 either an approximately steady load or one in which there is a peak1 where the boilers have been banked over night1 the capacity at which they may be run with the best economy will be found to be higher than for uniform #bd-;hour load conditions4 ,this is obviously due to original investment1 that is1 a given amount of invested capital can be made to earn a larger return through the higher overload1 and this will hold true to a point where the added return more than offsets the decrease in actual boiler efficiency4 ,here again the determining factors of what is the economical load are the fuel and labor cost balanced against the thermal efficiency4 ,with a load of this character1 there is another factor which may affect the economical plant operating load4 ,this is from the viewpoint of spare boilers4 ,that such added capacity in the way of spares is necessary is unquestionable4 ,since they must be installed1 therefore1 their presence leads to a fixed charge and it is probable that for the plant1 as a whole1 the economical load will be somewhat lower than if the boilers were considered only as spares4 ,that is1 it may be found best to operate these spares as a part of the regular equipment at all times except when other boilers are off for cleaning and repairs1 thus reducing the load on the individual boilers and increasing the efficiency4 ,under such conditions1 the added boiler units can be considered as spares only during such time as some of the boilers are not in operation4 ,due to the operating difficulties that may be encountered at the higher overloads1 it will ordinarily be found that the most economical ratings at which to run boilers for such load conditions will be between #aej and #age per cent of rating4 ,here again the maximum capacity at which the boilers may be run for the best plant economy is limited by the point at which the efficiency drops below what is warranted in view of the first cost of the apparatus4 #crd4 ,the #bd-;hour variable load4 ,this is a class of load carried by the central power station1 a load constant only in the sense that there are no periods of no load and which varies widely with different portions of the #bd hours4 ,with such a load it is particularly difficult to make any assertion as to the point of maximum economy that will hold for any station1 as this point is more than with any other class of load dependent upon the factors entering into the operation of each individual plant4 ,the methods of handling a load of this description vary probably more than with any other kind of load1 dependent upon fuel1 labor1 type of stoker1 flexibility of combined furnace and boiler etc41 etc4 ,in general1 under ordinary conditions such as appear in city central power station work where the maximum peaks occur but a few times a year1 the plant should be made of such size as to enable it to carry these peaks at the maximum possible overload on the boilers1 sufficient margin of course being allowed for insurance against interruption of service4 ,with the boilers operating at this maximum overload through the peaks a large sacrifice in boiler efficiency is allowable1 provided that by such sacrifice the overload expected is secured4 ,illustration3 ,portion of #dhij ,horse-power ,installation of ,babcock ,wilcox ,boilers at the ,billings ,sugar ,co41 ,billings1 ,mont4 #fid ,horse ,power of these ,boilers are ,equipped with ,babcock and ,wilcox ,chain ,grate ,stokers ,some methods of handling a load of this nature are given below3 ,certain plant operating conditions make it advisable1 from the standpoint of plant economy1 to carry whatever load is on the plant at any time on only such boilers as will furnish the power required when operating at ratings of1 say1 #aej to #bjj per cent4 ,that is1 all boilers which are in service are operated at such ratings at all times1 the variation in load being taken care of by the number of boilers on the line4 ,banked boilers are cut in to take care of increasing loads and peaks and placed again on bank when the peak periods have passed4 ,it is probable that this method of handling central station load is to-day the most generally used4 ,other conditions of operation make it advisable to carry the load on a definite number of boiler units1 operating these at slightly below their rated capacity during periods of light or low loads and securing the overload capacity during peaks by operating the same boilers at high ratings4 ,in this method there are no boilers kept on banked fires1 the spares being spares in every sense of the word4 ,a third method of handling widely varying loads which is coming somewhat into vogue is that of considering the plant as divided1 one part to take care of what may be considered the constant plant load1 the other to take care of the floating or variable load4 ,with such a method that portion of the plant carrying the steady load is so proportioned that the boilers may be operated at the point of maximum efficiency1 this point being raised to a maximum through the use of economizers and the general installation of any apparatus leading to such results4 ,the variable load will be carried on the remaining boilers of the plant under either of the methods just given1 that is1 at the high ratings of all boilers in service and banking others1 or a variable capacity from all boilers in service4 ,the opportunity is again taken to indicate the very general character of any statements made relative to the economical load for any plant and to emphasize the fact that each individual case must be considered independently1 with the conditions of operations applicable thereto4 ,with a thorough understanding of the meaning of boiler efficiency and capacity and their relation to each other1 it is possible to consider more specifically the selection of boilers4 ,the foremost consideration is1 without question1 the adaptability of the design selected to the nature of the work to be done4 ,an installation which is only temporary in its nature would obviously not warrant the first cost that a permanent plant would4 ,if boilers are to carry an intermittent and suddenly fluctuating load1 such as a hoisting load or a reversing mill load1 a design would have to be selected that would not tend to prime with the fluctuations and sudden demand for steam4 ,a boiler that would give the highest possible efficiency with fuel of one description1 would not of necessity give such efficiency with a different fuel4 ,a boiler of a certain design which might be good for small plant practice would not1 because of the limitations in practicable size of units1 be suitable for large installations4 ,a discussion of the relative value of designs can be carried on almost indefinitely but enough has been said to indicate that a given design will not serve satisfactorily under all conditions and that the adaptability to the service required will be dependent upon the fuel available1 the class of labor procurable1 the feed water that must be used1 the nature of the plant's load1 the size of the plant and the first cost warranted by the service the boiler is to fulfill4 ,,table #fj ,,actual ,,evaporation ,,for ,,different ,,pressures ,,and ,,temperatures ,,of ,,feed ,,water ,,corresponding ,,to ,,one ,,horse ,,power 7#cd ,,pounds ,,per ,,hour ,,from ,,and ,,at #bab ,,degrees ,,fahrenheit7 ---------------------------------------- ---------------------------------------- ---------------------------------------- ----------------- ,temperature of ,pressure by ,gauge--,pounds per ,square ,inch ,feed ,degrees ,fahrenheit #ej #fj #gj #hj #ij #ajj #aaj #abj #acj #adj #aej #afj #agj #ahj #aij #bjj #baj #bbj #bcj #bdj #bej ---------------------------------------- ---------------------------------------- ---------------------------------------- ---------------- #cb #bh4dabh4cfbh4bibh4bdbh4bjbh4afbh4acbh4j ibh4jgbh4jdbh4jbbg4iibg4igbg4iebg4idbg4i bbg4ijbg4hibg4hgbg4hfbg4hc #dj #bh4fabh4edbh4dibh4ddbh4djbh4cebh4cbbh4b ibh4bfbh4bcbh4babh4ahbh4afbh4adbh4abbh4a abh4jibh4jgbh4jfbh4jebh4jc #ej #bh4hebh4gibh4gcbh4fhbh4fdbh4fjbh4efbh4e cbh4ejbh4dgbh4debh4dcbh4djbh4chbh4cfbh4c ebh4ccbh4cabh4cjbh4bhbh4bg #fj #bi4ajbi4jdbh4ihbh4icbh4hhbh4hdbh4habh4g gbh4gdbh4gbbh4fibh4fgbh4febh4fbbh4fjbh4e ibh4egbh4eebh4edbh4ebbh4ea #gj #bi4cfbi4bibi4bcbi4ahbi4adbi4jibi4jfbi4j bbh4iibh4ifbh4idbh4ibbh4hibh4hgbh4hebh4h cbh4hbbh4hjbh4ghbh4ggbh4gf #hj #bi4fbbi4eebi4dibi4ddbi4cibi4cebi4cabi4b gbi4bdbi4bbbi4aibi4agbi4adbi4abbi4ajbi4j hbi4jgbi4jebi4jcbi4jbbi4jj #ij #bi4hhbi4habi4gebi4gjbi4febi4fabi4egbi4e cbi4ejbi4dgbi4debi4dbbi4djbi4chbi4cfbi4c dbi4cbbi4cjbi4bibi4bgbi4be #ajj #cj4aecj4jhcj4jbbi4ifbi4iabi4hgbi4hcbi4h jbi4gfbi4gcbi4gabi4fhbi4ffbi4fcbi4fabi4f jbi4ehbi4efbi4edbi4ecbi4ea #aaj #cj4dbcj4cecj4bicj4bccj4ahcj4adcj4ajcj4j fcj4jccj4jjbi4igbi4iebi4ibbi4ijbi4hhbi4h fbi4hdbi4hbbi4habi4gibi4gg #abj #cj4gjcj4fccj4efcj4eacj4dfcj4dacj4cgcj4c ccj4cjcj4bgcj4bdcj4bbcj4aicj4agcj4aecj4a ccj4aacj4jicj4jgcj4jfcj4jd #acj #cj4iicj4iacj4hdcj4gicj4gccj4ficj4fecj4f acj4egcj4edcj4ebcj4dicj4dgcj4ddcj4dbcj4d jcj4chcj4cfcj4cecj4cccj4ca #adj #ca4bhca4bjca4acca4jgca4jbcj4igcj4iccj4h icj4hfcj4hccj4hjcj4ggcj4gecj4gbcj4gjcj4f hcj4ffcj4fdcj4fbcj4facj4ei #aej #ca4ehca4dica4dbca4cfca4caca4bfca4bbca4a hca4adca4aaca4jhca4jfca4jcca4jacj4ihcj4i fcj4idcj4ibcj4iacj4hicj4hg #afj #ca4hgca4gica4gbca4ffca4faca4efca4eaca4d gca4ddca4djca4cgca4ceca4cbca4bica4bgca4b eca4bcca4baca4aica4ahca4af #agj #cb4ahcb4ajcb4jbca4ifca4iaca4hfca4haca4g gca4gcca4gjca4fgca4fdca4fbca4eica4egca4e dca4ebca4ejca4dica4dgca4df #ahj #cb4dicb4dacb4cccb4bgcb4bbcb4afcb4abcb4j hcb4jdcb4jjca4igca4ieca4ibca4hica4hgca4h dca4hbca4hjca4gica4ggca4ge #aij #cb4hacb4gbcb4fecb4eicb4eccb4dgcb4dccb4c hcb4cecb4cbcb4bicb4bfcb4bccb4bjcb4agcb4a ecb4accb4aacb4jicb4jgcb4je #bjj #cc4accc4jecb4igcb4iacb4hecb4gicb4gecb4g jcb4ffcb4fccb4fjcb4egcb4edcb4eacb4dicb4d fcb4ddcb4dbcb4djcb4chcb4cf #baj #cc4dgcc4chcc4cjcc4bdcc4ahcc4accc4jhcc4j ccb4iicb4iecb4ibcb4hicb4hfcb4hccb4hacb4g icb4gfcb4gdcb4gbcb4gjcb4fh ---------------------------------------- ---------------------------------------- ---------------------------------------- ----------------- ,the proper consideration can be given to the adaptability of any boiler for the service in view only after a thorough understanding of the requirements of a good steam boiler1 with the application of what has been said on the proper operation to the special requirements of each case4 ,of almost equal importance to the factors mentioned are the experience1 the skill and responsibility of the manufacturer4 ,with the design of boiler selected that is best adapted to the service required1 the next step is the determination of the boiler power requirements4 ,the amount of steam that must be generated is determined from the steam consumption of the prime movers4 ,it has already been indicated that such consumption can vary over wide limits with the size and type of the apparatus used1 but fortunately all types have been so tested that manufacturers are enabled to state within very close limits the actual consumption under any given set of conditions4 ,it is obvious that conditions of operation will have a bearing on the steam consumption that is as important as the type and size of the apparatus itself4 ,this being the case1 any tabular information that can be given on such steam consumption1 unless it be extended to an impracticable size1 is only of use for the most approximate work and more definite figures on this consumption should in all cases be obtained from the manufacturer of the apparatus to be used for the conditions under which it will operate4 ,to the steam consumption of the main prime movers1 there is to be added that of the auxiliaries4 ,again it is impossible to make a definite statement of what this allowance should be1 the figure depending wholly upon the type and the number of such auxiliaries4 ,for approximate work1 it is perhaps best to allow #ae or #bj per cent of the steam requirements of the main engines1 for that of auxiliaries4 ,whatever figure is used should be taken high enough to be on the conservative side4 ,when any such figures are based on the actual weight of steam required1 ,table #fj1 which gives the actual evaporation for various pressures and temperatures of feed corresponding to one boiler horse power 7#cd4e pounds of water per hour from and at #bab degrees71 may be of service4 ,with the steam requirements known1 the next step is the determination of the number and size of boiler units to be installed4 ,this is directly affected by the capacity at which a consideration of the economical load indicates is the best for the operating conditions which will exist4 ,the other factors entering into such determination are the size of the plant and the character of the feed water4 ,the size of the plant has its bearing on the question from the fact that higher efficiencies are in general obtained from large units1 that labor cost decreases with the number of units1 the first cost of brickwork is lower for large than for small size units1 a general decrease in the complication of piping1 etc41 and in general the cost per horse power of any design of boiler decreases with the size of units4 ,to illustrate this1 it is only necessary to consider a plant of1 say1 #aj1jjj boiler horse power1 consisting of #dj-bej horse-power units or #ag-fjj horse-power units4 ,the feed water available has its bearing on the subject from the other side1 for it has already been shown that very large units are not advisable where the feed water is not of the best4 ,the character of an installment is also a factor4 ,where1 say1 #ajjj horse power is installed in a plant where it is known what the ultimate capacity is to be1 the size of units should be selected with the idea of this ultimate capacity in mind rather than the amount of the first installation4 ,boiler service1 from its nature1 is severe4 ,all boilers have to be cleaned from time to time and certain repairs to settings1 etc41 are a necessity4 ,this makes it necessary1 in determining the number of boilers to be installed1 to allow a certain number of units or spares to be operated when any of the regular boilers must be taken off the line4 ,with the steam requirements determined for a plant of moderate size and a reasonably constant load1 it is highly advisable to install at least two spare boilers where a continuity of service is essential4 ,this permits the taking off of one boiler for cleaning or repairs and still allows a spare boiler in the event of some unforeseen occurrence1 such as the blowing out of a tube or the like4 ,investment in such spare apparatus is nothing more nor less than insurance on the necessary continuity of service4 ,in small plants of1 say1 #ejj or #fjj horse power1 two spares are not usually warranted in view of the cost of such insurance4 ,a large plant is ordinarily laid out in a number of sections or panels and each section should have its spare boiler or boilers even though the sections are cross connected4 ,in central station work1 where the peaks are carried on the boilers brought up from the bank1 such spares are1 of course1 in addition to these banked boilers4 ,from the aspect of cleaning boilers alone1 the number of spare boilers is determined by the nature of any scale that may be formed4 ,if scale is formed so rapidly that the boilers cannot be kept clean enough for good operating results1 by cleaning in rotation1 one at a time1 the number of spares to take care of such proper cleaning will naturally increase4 ,in view of the above1 it is evident that only a suggestion can be made as to the number and size of units1 as no recommendation will hold for all cases4 ,in general1 it will be found best to install units of the largest possible size compatible with the size of the plant and operating conditions1 with the total power requirements divided among such a number of units as will give proper flexibility of load1 with such additional units for spares as conditions of cleaning and insurance against interruption of service warrant4 ,in closing the subject of the selection of boilers1 it may not be out of place to refer to the effect of the builder's guarantee upon the determination of design to be used4 ,here in one of its most important aspects appears the responsibility of the manufacturer4 ,emphasis has been laid on the difference between test results and those secured in ordinary operating practice4 ,that such a difference exists is well known and it is now pretty generally realized that it is the responsible manufacturer who1 where guarantees are necessary1 submits the conservative figures1 figures which may readily be exceeded under test conditions and which may be closely approached under the ordinary plant conditions that will be met in daily operation4 ,,operation ,,and ,,care ,,of ,,boilers ,the general subject of boiler room practice may be considered from two aspects4 ,the first is that of the broad plant economy1 with a suggestion as to the methods to be followed in securing the best economical results with the apparatus at hand and procurable4 ,the second deals rather with specific recommendations which should be followed in plant practice1 recommendations leading not only to economy but also to safety and continuity of service4 ,such recommendations are dictated from an understanding of the nature of steam generating apparatus and its operation1 as covered previously in this book4 ,it has already been pointed out that the attention given in recent years to steam generating practice has come with a realization of the wide difference existing between the results being obtained in every-day operation and those theoretically possible4 ,the amount of such attention and regulation given to the steam generating end of a power plant1 however1 is comparatively small in relation to that given to the balance of the plant1 but it may be safely stated that it is here that there is the greatest assurance of a return for the attention given4 ,in the endeavor to increase boiler room efficiency1 it is of the utmost importance that a standard basis be set by which average results are to be judged4 ,with the theoretical efficiency obtainable varying so widely1 this standard cannot be placed at the highest efficiency that has been obtained regardless of operating conditions4 ,it is better set at the best obtainable results for each individual plant under its conditions of installation and daily operation4 ,with an individual standard so set1 present practice can only be improved by a systematic effort to approach this standard4 ,the degree with which operating results will approximate such a standard will be found to be directly proportional to the amount of intelligent supervision given the operation4 ,for such supervision to be given1 it is necessary to have not only a full realization of what the plant can do under the best operating conditions but also a full and complete knowledge of what it is doing under all of the different conditions that may arise4 ,what the plant is doing should be made a matter of continuous record so arranged that the results may be directly compared for any period or set of conditions1 and where such results vary from the standard set1 steps must be taken immediately to remedy the causes of such failings4 ,such a record is an important check in the losses in the plant4 ,as the size of the plant and the fuel consumption increase1 such a check of losses and recording of results becomes a necessity4 ,in the larger plants1 the saving of but a fraction of one per cent in the fuel bill represents an amount running into thousands of dollars annually1 while the expense of the proper supervision to secure such saving is small4 ,the methods of supervision followed in the large plants are necessarily elaborate and complete4 ,in the smaller plants the same methods may be followed on a more moderate scale with a corresponding saving in fuel and an inappreciable increase in either plant organization or expense4 ,there has been within the last few years a great increase in the practicability and reliability of the various types of apparatus by which the records of plant operation may be secured4 ,much of this apparatus is ingenious and1 considering the work to be done1 is remarkably accurate4 ,from the delicate nature of some of the apparatus1 the liability to error necessitates frequent calibration but even where the accuracy is known to be only within limits of1 say1 #e per cent either way1 the records obtained are of the greatest service in considering relative results4 ,some of the records desirable and the apparatus for securing them are given below4 ,illustration3 #bdjj ,horse-power ,installation of ,cross ,drum ,babcock ,wilcox ,boilers and ,superheaters at the ,westinghouse ,electric and ,manufacturing ,co41 ,east ,pittsburgh1 ,pa4 ,inasmuch as the ultimate measure of the efficiency of the boiler plant is the cost of steam generation1 the important records are those of steam generated and fuel consumed ,records of temperature1 analyses1 draft and the like1 serve as a check on this consumption1 indicating the distribution of the losses and affording a means of remedying conditions where improvement is possible4 ,coal ,records--,there are many devices on the market for conveniently weighing the coal used4 ,these are ordinarily accurate within close limits1 and where the size or nature of the plant warrants the investment in such a device1 its use is to be recommended4 ,the coal consumption should be recorded by some other method than from the weights of coal purchased4 ,the total weight gives no way of dividing the consumption into periods and it will unquestionably be found to be profitable to put into operation some scheme by which the coal is weighed as it is used4 ,in this way1 the coal consumption1 during any specific period of the plant's operation1 can be readily seen4 ,the simplest of such methods which may be used in small plants is the actual weighing on scales of the fuel as it is brought into the fire room and the recording of such weights4 ,aside from the actual weight of the fuel used1 it is often advisable to keep other coal records1 coal and ash analyses and the like1 for the evaporation to be expected will be dependent upon the grade of fuel used and its calorific value1 fusibility of its ash1 and like factors4 ,the highest calorific value for unit cost is not necessarily the indication of the best commercial results4 ,the cost of fuel is governed by this calorific value only when such value is modified by local conditions of capacity1 labor and commercial efficiency4 ,one of the important factors entering into fuel cost is the consideration of the cost of ash handling and the maintenance of ash handling apparatus if such be installed4 ,the value of a fuel1 regardless of its calorific value1 is to be based only on the results obtained in every-day plant operation4 ,coal and ash analyses used in connection with the amount of fuel consumed1 are a direct indication of the relation between the results being secured and the standard of results which has been set for the plant4 ,the methods of such analyses have already been described4 ,the apparatus is simple and the degree of scientific knowledge necessary is only such as may be readily mastered by plant operatives4 ,the ash content of a fuel1 as indicated from a coal analysis checked against ash weights as actually found in plant operation1 acts as a check on grate efficiency4 ,the effect of any saving in the ashes1 that is1 the permissible ash to be allowed in the fuel purchased1 is determined by the point at which the cost of handling1 combined with the falling off in the evaporation1 exceeds the saving of fuel cost through the use of poorer coal4 ,water ,records--,water records with the coal consumption1 form the basis for judging the economic production of steam4 ,the methods of securing such records are of later introduction than for coal1 but great advances have been made in the apparatus to be used4 ,here possibly1 to a greater extent than in any recording device1 are the records of value in determining relative evaporation1 that is1 an error is rather allowable provided such an error be reasonably constant4 ,the apparatus for recording such evaporation is of two general classes3 ,those measuring water before it is fed to the boiler and those measuring the steam as it leaves4 ,of the first1 the venturi meter is perhaps the best known1 though recently there has come into considerable vogue an apparatus utilizing a weir notch for the measuring of such water4 ,both methods are reasonably accurate and apparatus of this description has an advantage over one measuring steam in that it may be calibrated much more readily4 ,of the steam measuring devices1 the one in most common use is the steam flow meter4 ,provided the instruments are selected for a proper flow1 etc41 they are of inestimable value in indicating the steam consumption4 ,where such instruments are placed on the various engine room lines1 they will immediately indicate an excessive consumption for any one of the units4 ,with a steam flow meter placed on each boiler1 it is possible to fix relatively the amount produced by each boiler and1 considered in connection with some of the check records described below1 clearly indicate whether its portion of the total steam produced is up to the standard set for the over-all boiler room efficiency4 ,flue ,gas ,analysis--,the value of a flue gas analysis as a measure of furnace efficiency has already been indicated4 ,there are on the market a number of instruments by which a continuous record of the carbon dioxide in the flue gases may be secured and in general the results so recorded are accurate4 ,the limitations of an analysis showing only ,,co#b and the necessity of completing such an analysis with an ,orsat1 or like apparatus1 and in this way checking the automatic device1 have already been pointed out1 but where such records are properly checked from time to time and are used in conjunction with a record of flue temperatures1 the losses due to excess air or incomplete combustion and the like may be directly compared for any period4 ,such records act as a means for controlling excess air and also as a check on individual firemen4 ,where the size of a plant will not warrant the purchase of an expensive continuous ,,co#b recorder1 it is advisable to make analyses of samples for various conditions of firing and to install an apparatus whereby a sample of flue gas covering a period of1 say1 eight hours1 may be obtained and such a sample afterwards analyzed4 ,temperature ,records--,flue gas temperatures1 feed water temperatures and steam temperatures are all taken with recording thermometers1 any number of which will1 when properly calibrated1 give accurate results4 ,a record of flue temperatures is serviceable in checking stack losses and1 in general1 the cleanliness of the boiler4 ,a record of steam temperatures1 where superheaters are used1 will indicate excessive fluctuations and lead to an investigation of their cause4 ,feed temperatures are valuable in showing that the full benefit of the exhaust steam is being derived4 ,draft ,regulation--,as the capacity of a boiler varies with the combustion rate and this rate with the draft1 an automatic apparatus satisfactorily varying this draft with the capacity demands on the boiler will obviously be advantageous4 ,as has been pointed out1 any fuel has some rate of combustion at which the best results will be obtained4 ,in a properly designed plant where the load is reasonably steady1 the draft necessary to secure such a rate may be regulated automatically4 ,automatic apparatus for the regulation of draft has recently reached a stage of perfection which in the larger plants at any rate makes its installation advisable4 ,the installation of a draft gauge or gauges is strongly to be recommended and a record of such drafts should be kept as being a check on the combustion rates4 ,an important feature to be considered in the installing of all recording apparatus is its location4 ,thermometers1 draft gauges and flue gas sampling pipes should be so located as to give as nearly as possible an average of the conditions1 the gases flowing freely over the ends of the thermometers1 couples and sampling pipes4 ,with the location permanent1 there is no security that the samples may be considered an average but in any event comparative results will be secured which will be useful in plant operation4 ,the best permanent location of apparatus will vary considerably with the design of the boiler4 ,it may not be out of place to refer briefly to some of the shortcomings found in boiler room practice1 with a suggestion as to a means of overcoming them4 #ast4 ,it is sometimes found that the operating force is not fully acquainted with the boilers and apparatus4 ,probably the most general of such shortcomings is the fixed idea in the heads of the operatives that boilers run above their rated capacity are operating under a state of strain and that by operating at less than their rated capacity the most economical service is assured1 whereas1 by determining what a boiler will do1 it may be found that the most economical rating under the conditions of the plant will be considerably in excess of the builder's rating4 ,such ideas can be dislodged only by demonstrating to the operatives what maximum load the boilers can carry1 showing how the economy will vary with the load and the determining of the economical load for the individual plant in question4 #bnd4 ,stokers4 ,with stoker-fired boilers1 it is essential that the operators know the limitations of their stokers as determined by their individual installation4 ,a thorough understanding of the requirements of efficient handling must be insisted upon4 ,the operatives must realize that smokeless stacks are not necessarily the indication of good combustion for1 as has been pointed out1 absolute smokelessness is oftentimes secured at an enormous loss in efficiency through excess air4 ,another feature in stoker-fired plants is in the cleaning of fires4 ,it must be impressed upon the operatives that before the fires are cleaned they should be put into condition for such cleaning4 ,if this cleaning is done at a definite time1 regardless of whether the fires are in the best condition for cleaning1 there will be a great loss of good fuel with the ashes4 #crd4 ,it is necessary that in each individual plant there be a basis on which to judge the cleanliness of a boiler4 ,from the operative's standpoint1 it is probably more necessary that there be a thorough understanding of the relation between scale and tube difficulties than between scale and efficiency4 ,it is1 of course1 impossible to keep boilers absolutely free from scale at all times1 but experience in each individual plant determines the limit to which scale can be allowed to form before tube difficulties will begin or a perceptible falling off in efficiency will take place4 ,with such a limit of scale formation fixed1 the operatives should be impressed with the danger of allowing it to be exceeded4 #dth4 ,the operatives should be instructed as to the losses resulting from excess air due to leaks in the setting and as to losses in efficiency and capacity due to the by-passing of gases through the setting1 that is1 not following the path of the baffles as originally installed4 ,in replacing tubes and in cleaning the heating surfaces1 care must be taken not to dislodge baffle brick or tile4 ,illustration3 #bjjj ,horse-power ,installation of ,babcock ,wilcox ,boilers1 ,equipped with ,babcock ,wilcox ,chain ,grate ,stokers at the ,sunnyside ,plant of the ,pennsylvania ,tunnel and ,terminal ,railroad ,co41 ,long ,island ,city1 ,n4 ,y4 #eth4 ,that an increase in the temperature of the feed reduces the amount of work demanded from the boiler has been shown4 ,the necessity of keeping the feed temperature as high as the quantity of exhaust steam will allow should be thoroughly understood4 ,as an example of this1 there was a case brought to our attention where a large amount of exhaust steam was wasted simply because the feed pump showed a tendency to leak if the temperature of feed water was increased above #adj degrees4 ,the amount wasted was sufficient to increase the temperature to #ahj degrees but was not utilized simply because of the slight expense necessary to overhaul the feed pump4 ,the highest return will be obtained when the speed of the feed pumps is maintained reasonably constant for should the pumps run very slowly at times1 there may be a loss of the steam from other auxiliaries by blowing off from the heaters4 #fth4 ,with a view to checking steam losses through the useless blowing of safety valves1 the operative should be made to realize the great amount of steam that it is possible to get through a pipe of a given size4 ,oftentimes the fireman feels a sense of security from objections to a drop in steam simply because of the blowing of safety valves1 not considering the losses due to such a cause and makes no effort to check this flow either by manipulation of dampers or regulation of fires4 ,the few of the numerous shortcomings outlined above1 which may be found in many plants1 are almost entirely due to lack of knowledge on the part of the operating crew as to the conditions existing in their own plants and the better performances being secured in others4 ,such shortcomings can be overcome only by the education of the operatives1 the showing of the defects of present methods1 and instruction in better methods4 ,where such instruction is necessary1 the value of records is obvious4 ,there is fortunately a tendency toward the employment of a better class of labor in the boiler room1 a tendency which is becoming more and more marked as the realization of the possible saving in this end of the plant increases4 ,the second aspect of boiler room management1 dealing with specific recommendations as to the care and operation of the boilers1 is dictated largely by the nature of the apparatus4 ,some of the features to be watched in considering this aspect follow4 ,before placing a new boiler in service1 a careful and thorough examination should be made of the pressure parts and the setting4 ,the boiler as erected should correspond in its baffle openings1 where baffles are adjustable1 with the prints furnished for its erection1 and such baffles should be tight4 ,the setting should be so constructed that the boiler is free to expand without interfering with the brickwork4 ,this ability to expand applies also to blow-off and other piping4 ,after erection all mortar and chips of brick should be cleaned from the pressure parts4 ,the tie rods should be set up snug and then slacked slightly until the setting has become thoroughly warm after the first firing4 ,the boiler should be examined internally before starting to insure the absence of dirt1 any foreign material such as waste1 and tools4 ,oil and paint are sometimes found in the interior of a new boiler and where such is the case1 a quantity of soda ash should be placed within it1 the boiler filled with water to its normal level and a slow fire started4 ,after twelve hours of slow simmering1 the fire should be allowed to die out1 the boiler cooled slowly and then opened and washed out thoroughly4 ,such a proceeding will remove all oil and grease from the interior and prevent the possibility of foaming and tube difficulties when the boiler is placed in service4 ,the water column piping should be examined and known to be free and clear4 ,the water level1 as indicated by the gauge glass1 should be checked by opening the gauge cocks4 ,the method of drying out a brick setting before placing a boiler in operation is described later in the discussion of boiler settings4 ,a boiler should not be cut into the line with other boilers until the pressure within it is approximately that in the steam main4 ,the boiler stop valve should be opened very slowly until it is fully opened4 ,the arrangement of piping should be such that there can be no possibility of water collecting in a pocket between the boiler and the main1 from which it can be carried over into the steam line when a boiler is cut in4 ,in regular operation the safety valve and steam gauge should be checked daily4 ,in small plants the steam pressure should be raised sufficiently to cause the safety valves to blow1 at which time the steam gauge should indicate the pressure at which the valve is known to be set4 ,if it does not1 one is in error and the gauge should be compared with one of known accuracy and any error at once rectified4 ,in large plants such a method of checking would result in losses too great to be allowed4 ,here the gauges and valves are ordinarily checked at the time a boiler is cut out1 the valves being assured of not sticking by daily instantaneous opening through manipulation by hand of the valve lever4 ,the daily blowing of the safety valve acts not only as a check on the gauge but insures the valve against sticking4 ,the water column should be blown down thoroughly at least once on every shift and the height of water indicated by the glass checked by the gauge cocks4 ,the bottom blow-offs should be kept tight4 ,these should be opened at least once daily to blow from the mud drum any sediment that may have collected and to reduce the concentration4 ,the amount of blowing down and the frequency is1 of course1 determined by the nature of the feed water used4 ,in case of low water1 resulting either from carelessness or from some unforeseen condition of operation1 the essential object to be obtained is the extinguishing of the fire in the quickest possible manner4 ,where practicable1 this is best accomplished by the playing of a heavy stream of water from a hose on the fire4 ,another method1 perhaps not so efficient1 but more generally recommended1 is the covering of the fire with wet ashes or fresh fuel4 ,a boiler so treated should be cut out of line after such an occurrence and a thorough inspection made to ascertain what damage1 if any1 has been done before it is again placed in service4 ,the efficiency and capacity depend to an extent very much greater than is ordinarily realized upon the cleanliness of the heating surfaces1 both externally and internally1 and too much stress cannot be put upon the necessity for systematic cleaning as a regular feature in the plant operation4 ,the outer surfaces of the tubes should be blown free from soot at regular intervals1 the frequency of such cleaning periods being dependent upon the class of fuel used4 ,the most efficient way of blowing soot from the tubes is by means of a steam lance with which all parts of the surfaces are reached and swept clean4 ,there are numerous soot blowing devices on the market which are designed to be permanently fixed within the boiler setting4 ,where such devices are installed1 there are certain features that must be watched to avoid trouble4 ,if there is any leakage of water of condensation within the setting coming into contact with the boiler tubes1 it will tend toward corrosion1 or if in contact with the heated brickwork will cause rapid disintegration of the setting4 ,if the steam jets are so placed that they impinge directly against the tubes1 erosion may take place4 ,where such permanent soot blowers are installed1 too much care cannot be taken to guard against these possibilities4 ,internally1 the tubes must be kept free from scale1 the ingredients of which a study of the chapter on the impurities of water indicates are present in varying quantities in all feed waters4 ,not only has the presence of scale a direct bearing on the efficiency and capacity to be obtained from a boiler but its absence is an assurance against the burning out of tubes4 ,in the absence of a blow-pipe action of the flames1 it is impossible to burn a metal surface where water is in intimate contact with that surface4 ,in stoker-fired plants where a blast is used1 and the furnace is not properly designed1 there is a danger of a blow-pipe action if the fires are allowed to get too thin4 ,the rapid formation of steam at such points of localized heat may lead to the burning of the metal of the tubes4 ,any formation of scale on the interior surface of a boiler keeps the water from such a surface and increases its tendency to burn4 ,particles of loose scale that may become detached will lodge at certain points in the tubes and localize this tendency at such points4 ,it is because of the danger of detaching scale and causing loose flakes to be present that the use of a boiler compound is not recommended for the removal of scale that has already formed in a boiler4 ,this question is covered in the treatment of feed waters4 ,if oil is allowed to enter a boiler1 its action is the same as that of scale in keeping the water away from the metal surfaces4 ,illustration3 ,fig4 #da ,it has been proven beyond a doubt that a very large percentage of tube losses is due directly to the presence of scale which1 in many instances1 has been so thin as to be considered of no moment1 and the importance of maintaining the boiler heating surfaces in a clean condition cannot be emphasized too strongly4 ,the internal cleaning can best be accomplished by means of an air or water-driven turbine1 the cutter heads of which may be changed to handle various thicknesses of scale4 ,fig4 #da shows a turbine cleaner with various cutting heads1 which has been found to give satisfactory service4 ,where a water-driven turbine is used1 it should be connected to a pump which will deliver at least #abj gallons per minute per cleaner at #aej pounds pressure4 ,this pressure should never be less than #ij pounds if satisfactory results are desired4 ,where an air-driven turbine is used1 the pressure should be at least #ajj pounds1 though #aej pounds is preferable1 and sufficient water should be introduced into the tube to keep the cutting head cool and assist in washing down the scale as it is chipped off4 ,where scale has been allowed to accumulate to an excessive thickness1 the work of removal is difficult and tedious4 ,where such a heavy scale is of sulphate formation1 its removal may be assisted by filling the boiler with water to which there has been added a quantity of soda ash1 a bucketful to each drum1 starting a low fire and allowing the water to boil for twenty-four hours with no pressure on the boiler4 ,it should be cooled slowly1 drained1 and the turbine cleaner used immediately1 as the scale will tend to harden rapidly under the action of the air4 ,where oil has been allowed to get into a boiler1 it should be removed before placing the boiler in service1 as described previously where reference is made to its removal by boiling out with soda ash4 ,where pitting or corrosion is noted1 the parts affected should be carefully cleaned and the interior of the drums should be painted with white zinc if the boiler is to remain idle4 ,the cause of such action should be immediately ascertained and steps taken to apply the proper remedy4 ,when making an internal inspection of a boiler or when cleaning the interior heating surfaces1 great care must be taken to guard against the possibility of steam entering the boiler in question from other boilers on the same line either through the careless opening of the boiler stop valve or some auxiliary valve or from an open blow-off4 ,bad accidents through scalding have resulted from the neglect of this precaution4 ,boiler brickwork should be kept pointed up and all cracks filled4 ,the boiler baffles should be kept tight to prevent by-passing of any gases through the heating surfaces4 ,boilers should be taken out of service at regular intervals for cleaning and repairs4 ,when this is done1 the boiler should be cooled slowly1 and when possible1 be allowed to stand for twenty-four hours after the fire is drawn before opening4 ,the cooling process should not be hurried by allowing cold air to rush through the setting as this will invariably cause trouble with the brickwork4 ,when a boiler is off for cleaning1 a careful examination should be made of its condition1 both external and internal1 and all leaks of steam1 water and air through the setting stopped4 ,if water is allowed to come into contact with brickwork that is heated1 rapid disintegration will take place4 ,if water is allowed to come into contact with the metal of the boiler when out of service1 there is a likelihood of corrosion4 ,if a boiler is to remain idle for some time1 its deterioration may be much more rapid than when in service4 ,if the period for which it is to be laid off is not to exceed three months1 it may be filled with water while out of service4 ,the boiler should first be cleaned thoroughly1 internally and externally1 all soot and ashes being removed from the exterior of the pressure parts and any accumulation of scale removed from the interior surfaces4 ,it should then be filled with water1 to which five or six pails of soda ash have been added1 a slow fire started to drive the air from the boiler1 the fire drawn and the boiler pumped full4 ,in this condition it may be kept for some time without bad effects4 ,if the boiler is to be out of service for more than three months1 it should be emptied1 drained and thoroughly dried after being cleaned4 ,a tray of quick lime should be placed in each drum1 the boiler closed1 the grates covered and a quantity of quick lime placed on top of the covering4 ,special care should be taken to prevent air1 steam or water leaks into the boiler or onto the pressure parts to obviate danger of corrosion4 ,illustration3 #cjjj ,horse-power ,installation of ,babcock ,wilcox ,boilers in the ,main ,power ,plant1 ,chicago ,northwestern ,ry4 ,depot1 ,chicago1 ,ill4 ,,brickwork ,,boiler ,,settings ,a consideration of the losses in boiler efficiency1 due to the effects of excess air1 clearly indicates the necessity of maintaining the brick setting of a boiler tight and free from air leaks4 ,in view of the temperatures to which certain portions of such a setting are subjected1 the material to be used in its construction must be of the best procurable4 ,boiler settings to-day consist almost universally of brickwork--two kinds being used1 namely1 red brick and fire brick4 ,the red brick should only be used in such portions of the setting as are well protected from the heat4 ,in such location1 their service is not so severe as that of fire brick and ordinarily1 if such red brick are sound1 hard1 well burned and uniform1 they will serve their purpose4 ,the fire brick should be selected with the greatest care1 as it is this portion of the setting that has to endure the high temperatures now developed in boiler practice4 ,to a great extent1 the life of a boiler setting is dependent upon the quality of the fire brick used and the care exercised in its laying4 ,the best fire brick are manufactured from the fire clays of ,pennsylvania4 ,south and west from this locality the quality of fire clay becomes poorer as the distance increases1 some of the southern fire clays containing a considerable percentage of iron oxide4 ,until very recently1 the important characteristic on which to base a judgment of the suitability of fire brick for use in connection with boiler settings has been considered the melting point1 or the temperature at which the brick will liquify and run4 ,experience has shown1 however1 that this point is only important within certain limits and that the real basis on which to judge material of this description is1 from the boiler man's standpoint1 the quality of plasticity under a given load4 ,this tendency of a brick to become plastic occurs at a temperature much below the melting point and to a degree that may cause the brick to become deformed under the stress to which it is subjected4 ,the allowable plastic or softening temperature will naturally be relative and dependent upon the stress to be endured4 ,with the plasticity the determining factor1 the perfect fire brick is one whose critical point of plasticity lies well above the working temperature of the fire4 ,it is probable that there are but few brick on the market which would not show1 if tested1 this critical temperature at the stress met with in arch construction at a point less than #bdjj degrees4 ,the fact that an arch will stand for a long period under furnace temperatures considerably above this point is due entirely to the fact that its temperature as a whole is far below the furnace temperature and only about #aj per cent of its cross section nearest the fire approaches the furnace temperature4 ,this is borne out by the fact that arches which are heated on both sides to the full temperature of an ordinary furnace will first bow down in the middle and eventually fall4 ,a method of testing brick for this characteristic is given in the ,technologic ,paper ,no4 #g of the ,bureau of ,standards dealing with ,the testing of clay refractories with special reference to their load carrying capacity at furnace temperatures4 ,referring to the test for this specific characteristic1 this publication recommends the following3 ,when subjected to the load test in a manner substantially as described in this bulletin1 at #acej degrees centigrade 7#bdfb degrees ,fahrenheit71 and under a load of #ej pounds per square inch1 a standard fire brick tested on end should show no serious deformation and should not be compressed more than one inch1 referred to the standard length of nine inches4 ,in the ,bureau of ,standards test for softening temperature1 or critical temperature of plasticity under the specified load1 the brick are tested on end4 ,in testing fire brick for boiler purposes such a method might be criticised1 because such a test is a compression test and subject to errors from unequal bearing surfaces causing shear4 ,furthermore1 a series of samples1 presumably duplicates1 will not fail in the same way1 due to the mechanical variation in the manufacture of the brick4 ,arches that fail through plasticity show that the tensile strength of the brick is important1 this being evidenced by the fact that the bottom of a wedge brick in an arch that has failed is usually found to be wider than the top and the adjacent bricks are firmly cemented together4 ,a better method of testing is that of testing the brick as a beam subjected to its own weight and not on end4 ,this method has been used for years in ,germany and is recommended by the highest authorities in ceramics4 ,it takes into account the failure by tension in the brick as well as by compression and thus covers the tension element which is important in arch construction4 ,the plastic point under a unit stress of #ajj pounds per square inch1 which may be taken as the average maximum arch stress1 should be above #bhjj degrees to give perfect results and should be above #bdjj degrees to enable the brick to be used with any degree of satisfaction4 ,the other characteristics by which the quality of a fire brick is to be judged are3 ,fusion point4 ,in view of the fact that the critical temperature of plasticity is below the fusion point1 this is only important as an indication from high fusion point of a high temperature of plasticity4 ,hardness4 ,this is a relative quality based on an arbitrary scale of #aj and is an indication of probable cracking and spalling4 ,expansion4 ,the lineal expansion per brick in inches4 ,this characteristic in conjunction with hardness is a measure of the physical movement of the brick as affecting a mass of brickwork1 such movement resulting in cracked walls1 etc4 ,the expansion will vary between wide limits in different brick and provided such expansion is not in excess of1 say1 4#je inch in a #i-;inch brick1 when measured at #bfjj degrees1 it is not particularly important in a properly designed furnace1 though in general the smaller the expansion the better4 ,compression4 ,the strength necessary to cause crushing of the brick at the center of the #d inch face by a steel block one inch square4 ,the compression should ordinarily be low1 a suggested standard being that a brick show signs of crushing at #gejj pounds4 ,size of ,nodules4 ,the average size of flint grains when the brick is carefully crushed4 ,the scale of these sizes may be considered3 ,small1 size of anthracite rice2 large1 size of anthracite pea4 ,ratio of ,nodules4 ,the percentage of a given volume occupied by the flint grains4 ,this scale may be considered3 ,high1 #ij to #ajj per cent2 medium1 #ej to #ij per cent2 low1 #aj to #ej per cent4 ,the statement of characteristics suggested as desirable1 are for arch purposes where the hardest service is met4 ,for side wall purposes the compression and hardness limit may be raised considerably and the plastic point lowered4 ,aside from the physical properties by which a fire brick is judged1 it is sometimes customary to require a chemical analysis of the brick4 ,such an analysis is only necessary as determining the amount of total basic fluxes 7,k#b,o1 ,na#b,o1 ,ca,o1 ,mg,o and ,fe,o74 ,these fluxes are ordinarily combined into one expression1 indicated by the symbol ,,ro4 ,this total becomes important only above #j4b molecular equivalent as expressed in ceramic empirical formulae1 and this limit should not be exceeded4#ge ,from the nature of fire brick1 their value can only be considered from a relative standpoint4 ,generally speaking1 what are known as first-grade fire brick may be divided into three classes1 suitable for various conditions of operation1 as follows3 ,class ,a4 ,for stoker-fired furnaces where high overloads are to be expected or where other extreme conditions of service are apt to occur4 ,class ,b4 ,for ordinary stoker settings where there will be no excessive overloads required from the boiler or any hand-fired furnaces where the rates of driving will be high for such practice4 ,class ,c4 ,for ordinary hand-fired settings where the presumption is that the boilers will not be overloaded except at rare intervals and for short periods only4 ,table #fa gives the characteristics of these three classes according to the features determining the quality4 ,this table indicates that the hardness of the brick in general increases with the poorer qualities4 ,provided the hardness is sufficient to enable the brick to withstand its load1 additional hardness is a detriment rather than an advantage4 ,,table #fa ,,approximate ,,classification ,,of ,,fire ,,brick ,characteristics ,class ,a ,class ,b ,class ,c ,fuse ,point1 ,degrees ,safe at ,degrees ,safe at ,degrees ,safe at ,degrees ,fahrenheit #cbjj-ccjj #bijj-cbjj #bijj-cjjj ,compression ,pounds #fejj-gejj #gejj-aa1jjj #hejj-ae1jjj ,hardness ,relative #a-b #b-d #d-f ,size of ,nodules ,medium ,medium to ,medium to ,large ,medium ,large ,ratio of ,nodules ,high ,medium to ,high ,medium ,low to ,medium ,an approximate determination of the quality of a fire brick may be made from the appearance of a fracture4 ,where such a fracture is open1 clean1 white and flinty1 the brick in all probability is of a good quality4 ,if this fracture has the fine uniform texture of bread1 the brick is probably poor4 ,in considering the heavy duty of brick in boiler furnaces1 experience shows that arches are the only part that ordinarily give trouble4 ,these fail from the following causes3 ,bad workmanship in laying up of brick4 ,this feature is treated below4 ,the tendency of a brick to become plastic at a temperature below the fusing point4 ,the limits of allowable plastic temperature have already been pointed out4 ,spalling4 ,this action occurs on the inner ends of combustion arches where they are swept by gases at a high velocity at the full furnace temperature4 ,the most troublesome spalling arises through cold air striking the heated brickwork4 ,failure from this cause is becoming rare1 due to the large increase in number of stoker installations in which rapid temperature changes are to a great degree eliminated4 ,furthermore1 there are a number of brick on the market practically free from such defects and where a new brick is considered1 it can be tried out and if the defect exists1 can be readily detected and the brick discarded4 ,failures of arches from the expansive power of brick are also rare1 due to the fact that there are a number of brick in which the expansion is well within the allowable limits and the ease with which such defects may be determined before a brick is used4 ,failures through chemical disintegration4 ,failure through this cause is found only occasionally in brick containing a high percentage of iron oxide4 ,with the grade of brick selected best suited to the service of the boiler to be set1 the other factor affecting the life of the setting is the laying4 ,it is probable that more setting difficulties arise from the improper workmanship in the laying up of brick than from poor material1 and to insure a setting which will remain tight it is necessary that the masonry work be done most carefully4 ,this is particularly true where the boiler is of such a type as to require combustion arches in the furnace4 ,red brick should be laid in a thoroughly mixed mortar composed of one volume of ,portland cement1 #c volumes of unslacked lime and #af volumes of clear sharp sand4 ,not less than #b bushels of lime should be used in the laying up of #ajjj brick4 ,each brick should be thoroughly embedded and all joints filled4 ,where red brick and fire brick are both used in the same wall1 they should be carried up at the same time and thoroughly bonded to each other4 ,all fire brick should be dry when used and protected from moisture until used4 ,each brick should be dipped in a thin fire clay wash1 rubbed and shoved into place1 and tapped with a wooden mallet until it touches the brick next below it4 ,it must be recognized that fire clay is not a cement and that it has little or no holding power4 ,its action is that of a filler rather than a binder and no fire-clay wash should be used which has a consistency sufficient to permit the use of a trowel4 ,all fire-brick linings should be laid up four courses of headers and one stretcher4 ,furnace center walls should be entirely of fire brick4 ,if the center of such walls are built of red brick1 they will melt down and cause the failure of the wall as a whole4 ,fire-brick arches should be constructed of selected brick which are smooth1 straight and uniform4 ,the frames on which such arches are built1 called arch centers1 should be constructed of batten strips not over #b inches wide4 ,the brick should be laid on these centers in courses1 not in rings1 each joint being broken with a bond equal to the length of half a brick4 ,each course should be first tried in place dry1 and checked with a straight edge to insure a uniform thickness of joint between courses4 ,each brick should be dipped on one side and two edges only and tapped into place with a mallet4 ,wedge brick courses should be used only where necessary to keep the bottom faces of the straight brick course in even contact with the centers4 ,when such contact cannot be exactly secured by the use of wedge brick1 the straight brick should lean away from the center of the arch rather than toward it4 ,when the arch is approximately two-thirds completed1 a trial ring should be laid to determine whether the key course will fit4 ,when some cutting is necessary to secure such a fit1 it should be done on the two adjacent courses on the side of the brick away from the key4 ,it is necessary that the keying course be a true fit from top to bottom1 and after it has been dipped and driven it should not extend below the surface of the arch1 but preferably should have its lower ledge one-quarter inch above this surface4 ,after fitting1 the keys should be dipped1 replaced loosely1 and the whole course driven uniformly into place by means of a heavy hammer and a piece of wood extending the full length of the keying course4 ,such a driving in of this course should raise the arch as a whole from the center4 ,the center should be so constructed that it may be dropped free of the arch when the key course is in place and removed from the furnace without being burned out4 ,illustration3 ,a ,typical ,steel ,casing for a ,babcock ,wilcox ,boiler ,built by ,the ,babcock ,wilcox ,co4 ,care of ,brickwork--,before a boiler is placed in service1 it is essential that the brickwork setting be thoroughly and properly dried1 or otherwise the setting will invariably crack4 ,the best method of starting such a process is to block open the boiler damper and the ashpit doors as soon as the brickwork is completed and in this way maintain a free circulation of air through the setting4 ,if possible1 such preliminary drying should be continued for several days before any fire is placed in the furnace4 ,when ready for the drying out fire1 wood should be used at the start in a light fire which may be gradually built up as the walls become warm4 ,after the walls have become thoroughly heated1 coal may be fired and the boiler placed in service4 ,as already stated1 the life of a boiler setting is dependent to a large extent upon the material entering into its construction and the care with which such material is laid4 ,a third and equally important factor in the determining of such life is the care given to the maintaining of the setting in good condition after the boiler is placed in operation4 ,this feature is discussed more fully in the chapter dealing with general boiler room management4 ,steel ,casings--,in the chapter dealing with the losses operating against high efficiencies as indicated by the heat balance1 it has been shown that a considerable portion of such losses is due to radiation and to air infiltration into the boiler setting4 ,these losses have been variously estimated from #b to #aj per cent1 depending upon the condition of the setting and the amount of radiation surface1 the latter in turn being dependent upon the size of the boiler used4 ,in the modern efforts after the highest obtainable plant efficiencies much has been done to reduce such losses by the use of an insulated steel casing covering the brickwork4 ,in an average size boiler unit the use of such casing1 when properly installed1 will reduce radiation losses from one to two per cent41 over what can be accomplished with the best brick setting without such casing and1 in addition1 prevent the loss due to the infiltration of air1 which may amount to an additional five per cent41 as compared with brick settings that are not maintained in good order4 ,steel plate1 or steel plate backed by asbestos mill-board1 while acting as a preventative against the infiltration of air through the boiler setting1 is not as effective from the standpoint of decreasing radiation losses as a casing properly insulated from the brick portion of the setting by magnesia block and asbestos mill-board4 ,a casing which has been found to give excellent results in eliminating air leakage and in the reduction of radiation losses is clearly illustrated on page #cjf4 ,many attempts have been made to use some material other than brick for boiler settings but up to the present nothing has been found that may be considered successful or which will give as satisfactory service under severe conditions as properly laid brickwork4 ,,boiler ,,room ,,piping ,in the design of a steam plant1 the piping system should receive the most careful consideration4 ,aside from the constructive details1 good practice in which is fairly well established1 the important factors are the size of the piping to be employed and the methods utilized in avoiding difficulties from the presence in the system of water of condensation and the means employed toward reducing radiation losses4 ,engineering opinion varies considerably on the question of material of pipes and fittings for different classes of work1 and the following is offered simply as a suggestion of what constitutes good representative practice4 ,all pipe should be of wrought iron or soft steel4 ,pipe at present is made in standard1 extra strong#gf and double extra strong weights4 ,until recently1 a fourth weight approximately #aj per cent lighter than standard and known as ,merchants was built but the use of this pipe has largely gone out of practice4 ,pipe sizes1 unless otherwise stated1 are given in terms of nominal internal diameter4 ,table #fb gives the dimensions and some general data on standard and extra strong wrought-iron pipe4 ,,table #fb ,,dimensions ,,of ,,standard ,,and ,,extra ,,strong#gf ,,wrought-,,iron ,,and ,,steel ,,pipe ,diameter ,circumference ,external ,internal ,external ,internal ,standard,standard and and ,nominal ,extra ,standard ,extra ,extra ,standard ,extra ,size ,strong ,strong ,strong ,strong #a_/h 4#dje 4#bfi 4#bae #a4bgb 4#hdh 4#fge #a_/d 4#edj 4#cfd 4#cjb #a4fif #a4add 4#idi #c_/h 4#fge 4#dic 4#dbc #b4aba #a4eeb #a4cbi #a_/b 4#hdj 4#fbb 4#edf #b4fci #a4ieg #a4gae #c_/d #a4jej 4#hbd 4#gdb #c4bii #b4ehi #b4cca #a #a4cae #a4jdi 4#ieg #d4aca #c4bib #c4jjg #a-a_/d #a4ffj #a4chj #a4bgh #e4bae #d4cce #d4jae #a-a_/b #a4ijj #a4faj #a4ejj #e4ifi #e4jfa #d4gab #b #b4cge #b4jfg #a4ici #g4dfa #f4did #f4jib #b-a_/b #b4hge #b4dfi #b4cbc #i4jcb #g4gec #g4bih #c #c4ejj #c4jfh #b4ijj #aj4iif #i4fcf #i4aaa #c-a_/b #d4jjj #c4edh #c4cfd #ab4eff #aa4adf #aj4efh #d #d4ejj #d4jbf #c4hbf #ad4acg #ab4fdh #ab4jbj #d-a_/b #e4jjj #d4ejf #d4bij #ae4gjh #ad4afb #ac4dgg #e #e4efc #e4jdg #d4hac #ag4dgg #ae4hdi #ae4aba #f #f4fbe #f4jfe #e4gfa #bj4hac #ai4jed #ah4jii #g #g4fbe #g4jbc #f4fbe #bc4iee #bb4jfc #bj4hac #h #h4fbe #g4iha #g4fbe #bg4jif #be4jgf #bc4iee #i #i4fbe #h4ida #h4fbe #cj4bch #bh4jhi #bg4jif #aj #aj4gej #aj4jbj #i4gej #cc4ggb #ca4dgg #cj4fca #aa #aa4gej #aa4jjj #aj4gej #cf4iad #cd4eeh #cc4ggb #ab #ab4gej #ab4jjj #aa4gej #dj4jee #cg4gjj #cf4iad ,length ,internal of ,nominal ,weight ,transverse ,pipe in ,pounds per ,area ,feet per ,foot ,square ,foot of ,nominal ,standard ,extra ,external,standard ,extra ,size ,strong ,surface ,strong #a_/h 4#jegc 4#jcfc #i4ddj 4#bdd 4#cad #a_/d 4#ajda 4#jgaf #g4jge 4#dbd 4#ece #c_/h 4#aiag 4#adje #e4feg 4#efg 4#gch #a_/b 4#cjdh 4#bcda #d4edg 4#hej #a4jhg #c_/d 4#eccc 4#dcbd #c4fcg #a4acj #a4dgc #a 4#hfbf 4#gaic #b4ijd #a4fgh #b4aga #a-a_/d #a4dif #a4bhg #b4cja #b4bgb #b4iif #a-a_/b #b4jch #a4gfg #b4jaj #b4gag #c4fca #b #c4cef #b4iec #a4fjh #c4feb #e4jbb #b-a_/b #d4ghd #d4bch #a4cbh #e4gic #g4ffa #c #g4chh #f4fje #a4jia #g4ege #aj4beb #c-a_/b #i4hhg #h4hhh 4#iee #i4aji #ab4eje #d #ab4gcj #aa4dig 4#hdi #aj4gij #ad4ihc #d-a_/b #ae4ifa #ad4ded 4#gfd #ab4ech #ag4faa #e #ai4iij #ah4aid 4#fhg #ad4fag #bj4ggh #f #bh4hhh #bf4jfg 4#egg #ah4igd #bh4egc #g #ch4gch #cd4dgb 4#eja #bc4edd #ch4jdh #h #ej4jdj #de4ffd 4#ddc #bh4edd #dc4chh #i #fb4ggf #eh4dbf 4#cig #cc4ijg #dh4gbh #aj #gh4hci #gd4ffb 4#cee #dj4dhc #ed4gce #aa #ie4jcc #ij4gfc 4#cbe #de4eeg #fj4jge #ab #aac4jih #ajh4dc 4#bii #di4efb #fe4dae ,dimensions are nominal and except where noted are in inches4 ,in connection with pipe sizes1 ,table #fc1 giving certain tube data may be found to be of service4 ,,table #fc ,,tube ,,data1 ,,standard ,,open ,,hearth ,,or ,,lap ,,welded ,,steel ,,tubes ---------------------------------------- --------------------- ,s ,e ,d,b ,t ,i ,d ,circumference ,transverse ,square ,length ,nominal i x i4 h n i ,area ,feet in ,feet,weight z t a,w i t a ,square ,inches of per ,pounds e e m4 c e m ------------------------ ,exter ,square per r e k r e ,exter-,inter-,exter-,inter- -nal ,foot of ,foot n t,g n n t nal nal nal nal ,surface ,exter a ea e a e per -nal l ru s l r ,foot of,surface g s ,length e ---------------------------------------- --------------------- #a-a_/baj4acda4bcb #d4gab #c4hgja4gfgaa4aiba 4#cib #b4edf #a4iee #a-a_/b #i4adha4bjd #d4gab #c4ghba4gfgaa4ache 4#cib #b4edf #b4acg #a-a_/b #h4afea4agj #d4gab #c4fgfa4gfgaa4jgea 4#cib #b4edf #b4cec #b #aj4acda4gcb #f4bhc #e4ddac4adafb4cefj 4#ebc #a4iji #b4fgj #b #i4adha4gjd #f4bhc #e4cecc4adafb4bggh 4#ebc #a4iji #b4ibg #b #h4afea4fgj #f4bhc #e4bdfc4adafb4aijd 4#ebc #a4iji #c4bcd #c-a_/daa4abjc4jajaj4baj #i4defh4biehg4aaeg 4#hej #a4age #d4jaa #c-a_/daj4acdb4ihbaj4baj #i4cfhh4biehf4ihdj 4#hej #a4age #d4dei #c-a_/d #i4adhb4iedaj4baj #i4bhjh4biehf4hece 4#hej #a4age #d4ijc #d #aj4acdc4gcbab4effaa4gbdab4effaj4ici #a4jdg 4#ied #e4ecb #d #i4adhc4gjdab4effaa4fcfab4effaj4gge #a4jdg 4#ied #f4jjj #d #h4afec4fgjab4effaa4ecjab4effaj4egh #a4jdg 4#ied #f4geh ---------------------------------------- --------------------- ,dimensions are nominal and except where noted are in inches4 ,pipe ,material and ,thickness--,for saturated steam pressures not exceeding #afj pounds1 all pipe over #ad inches should be #c_/h inch thick ,o4 ,d4 pipe4 ,all other pipe should be standard full weight1 except high pressure feed#gg and blow-off lines1 which should be extra strong4 ,for pressures above #aej pounds up to #bjj pounds with superheated steam1 all high pressure feed and blow-off lines1 high pressure steam lines having threaded flanges1 and straight runs and bends of high pressure steam lines #f inches and under having ,van ,stone joints should be extra strong4 ,all piping #g inches and over having ,van ,stone joints should be full weight soft flanging pipe of special quality4 ,pipe #ad inches and over should be #c_/h inch thick ,o4 ,d4 pipe4 ,all pipes for these pressures not specified above should be full weight pipe4 ,flanges--,for saturated steam1 #afj pounds working pressure1 all flanges for wrought-iron pipe should be cast-iron threaded4 ,all high pressure threaded flanges should have the diameter thickness and drilling in accordance with the manufacturer's standard for extra heavy flanges4 ,all low pressure flanges should have diameter1 thickness and drilling in accordance with manufacturer's standard for standard flanges4 ,the flanges on high pressure lines should be counterbored to receive pipe and prevent the threads from shouldering4 ,the pipe should be screwed through the flange at least #a_/af inch1 placed in machine and after facing off the end one smooth cut should be taken over the face of the flange to make it square with the axis of the pipe4 ,illustration3 #bjjj ,horse-power ,installation of ,babcock ,wilcox ,boilers and ,superheaters1 ,equipped with ,babcock ,wilcox ,chain ,grate ,stokers at the ,kentucky ,electric ,co41 ,louisville1 ,ky4 ,for pressures above #afj pounds1 where superheated steam is used1 all high pressure steam lines #d inches and over should have solid rolled steel flanges and special upset lapped joints4 ,in the manufacture of such joints1 the ends of the pipe are heated and upset against the face of a holding mandrel conforming to the shape of the flange1 the lapped portion of the pipe being flattened out against the face of the mandrel1 the upsetting action maintaining the desired thickness of the lap4 ,when cool1 both sides of the lap are faced to form a uniform thickness and an even bearing against flange and gasket4 ,the joint1 therefore1 is a strictly metal to metal joint1 the flanges merely holding the lapped ends of the pipe against the gasket4 ,a special grade of soft flanging pipe is selected to prevent breaking4 ,the bending action is a severe test of the pipe and if it withstands the bending process and the pressure tests1 the reliability of the joint is assured4 ,such a joint is called a ,van ,stone joint1 though many modifications and improvements have been made since the joint was originally introduced4 ,the diameter and thickness of such flanges should be special extra heavy4 ,such flanges should be turned to diameter1 their fronts faced and the backs machined in lieu of spot facing4 ,in lines other than given for pressures over #aej pounds1 all flanges for wrought-iron pipe should be threaded4 ,all threaded flanges for high pressure superheated lines #c inches and under should be semi-steel extra heavy4 ,flanges for other than steam lines should be manufacturer's standard extra heavy4 ,welded flanges are frequently used in place of those described with satisfactory results4 ,fittings--,for saturated steam under pressures up to #afj pounds1 all fittings #c inches and under should be screwed4 ,fittings #d inches and over should have flanged ends4 ,fittings for this pressure should be of cast iron and should have heavy leads and full taper threads4 ,flanged fittings in high pressure lines should be extra heavy1 and in low pressure lines standard weight4 ,where possible in high pressure flanges and fittings1 bolt surfaces should be spot faced to provide suitable bearing for bolt heads and nuts4 ,fittings for superheated steam up to #gj degrees at pressures above #afj pounds are sometimes of cast iron4#gh ,for superheat above #gj degrees such fittings should be steel castings and in general these fittings are recommended for any degree of superheat4 ,fittings for other than high pressure work may be of cast iron1 except where superheated steam is carried1 where they should be of wrought steel or hard metal4 ,fittings #c inches and under should be screwed1 #d inches and over flanged4 ,flanges for pressures up to #afj pounds in pipes and fittings for low pressure lines1 and any fittings for high pressure lines should have plain faces1 smooth tool finish1 scored with ,v-shaped grooves for rubber gaskets4 ,high pressure line flanges should have raised faces1 projecting the full available diameter inside the bolt holes4 ,these faces should be similarly scored4 ,all pipe inch and under should have ground joint unions suitable for the pressure required4 ,pipe inch and over should have cast-iron flanged unions4 ,unions are to be preferred to wrought-iron couplings wherever possible to facilitate dismantling4 ,valves--,for #aej pounds working pressure1 saturated steam1 all valves #b inches and under may have screwed ends2 #b inches and over should be flanged4 ,all high pressure steam valves #f inches and over should have suitable by-passes4 ,all valves for use with superheated steam should be of special construction4 ,for pressures above #afj pounds1 where the superheat does not exceed #gj degrees1 valve bodies1 caps and yokes are sometimes made of cast iron1 though ordinarily semi-steel will give better satisfaction4 ,the spindles of such valves should be of bronze and there should be special necks with condensing chambers to prevent the superheated steam from blowing through the packing4 ,for pressures over #afj pounds and degrees of superheat above #gj1 all valves #c inches and over should have valve bodies1 caps and yokes of steel castings4 ,spindles should be of some non-corrosive metal1 such as monel metal4 ,seat rings should be removable of the same non-corrosive metal as should the spindle seats and plug faces4 ,all salt water valves should have bronze spindles1 sleeves and packing seats4 ,the suggestions as to flanges for different classes of service made on page #caa hold as well for valve flanges1 except that such flanges are not scored4 ,automatic stop and check valves are coming into general use with boilers and such use is compulsory under the boiler regulations of certain communities4 ,where used1 they should be preferably placed directly on the boiler nozzle4 ,where two or more boilers are on one line1 in addition to the valve at the boiler1 whether this be an automatic valve or a gate valve1 there should be an additional gate valve on each boiler branch at the main steam header4 ,relief valves should be furnished at the discharge side of each feed pump and on the discharge side of each feed heater of the closed type4 ,feed ,lines--,feed lines should in all instances be made of extra strong pipe due to the corrosive action of hot feed water4 ,while it has been suggested above that cast-iron threaded flanges should be used in such lines1 due to the sudden expansion of such pipe in certain instances cast-iron threaded flanges crack before they become thoroughly heated and expand1 and for this reason cast-steel threaded flanges will give more satisfactory results4 ,in some instances1 wrought-steel and ,van ,stone joints have been used in feed lines and this undoubtedly is better practice than the use of cast-steel threaded work1 though the additional cost is not warranted in all stations4 ,feed valves should always be of the globe pattern4 ,a gate valve cannot be closely regulated and often clatters owing to the pulsations of the feed pump4 ,gaskets--,for steam and water lines where the pressure does not exceed #afj pounds1 wire insertion rubber gaskets #a_/af inch thick will be found to give good service4 ,for low pressure lines1 canvas insertion black rubber gaskets are ordinarily used4 ,for oil lines special gaskets are necessary4 ,for pressure above #afj pounds carrying superheated steam1 corrugated steel gaskets extending the full available diameter inside of the bolt holes give good satisfaction4 ,for high pressure water lines wire inserted rubber gaskets are used1 and for low pressure flanged joints canvas inserted rubber gaskets4 ,size of ,steam ,lines--,the factors affecting the proper size of steam lines are the radiation from such lines and the velocity of steam within them4 ,as the size of the steam line increases1 there will be an increase in the radiation4#gi ,as the size decreases1 the steam velocity and the pressure drop for a given quantity of steam naturally increases4 ,there is a marked tendency in modern practice toward higher steam velocities1 particularly in the case of superheated steam4 ,it was formerly considered good practice to limit this velocity to #fjjj feet per minute but this figure is to-day considered low4 ,in practice the limiting factor in the velocity advisable is the allowable pressure drop4 ,in the description of the action of the throttling calorimeter1 it has been demonstrated that there is no loss accompanying a drop in pressure1 the difference in energy between the higher and lower pressures appearing as heat1 which1 in the case of steam flowing through a pipe1 may evaporate any condensation present or may be radiated from the pipe4 ,a decrease in pipe area decreases the radiating surface of the pipe and thus the possible condensation4 ,as the heat liberated by the pressure drop is utilized in overcoming or diminishing the tendency toward condensation and the heat loss through radiation1 the steam as it enters the prime mover will be drier or more highly superheated where high steam velocities are used than where they are lower1 and if enough excess pressure is carried at the boilers to maintain the desired pressure at the prime mover1 the pressure drop results in an actual saving rather than a loss4 ,the whole is analogous to standard practice in electrical distributing systems where generator voltage is adjusted to suit the loss in the feeder lines4 ,in modern practice1 with superheated steam1 velocities of #ae1jjj feet per minute are not unusual and this figure is very frequently exceeded4 ,piping ,system ,design--,with the proper size of pipe to be used determined1 the most important factor is the provision for the removal of water of condensation that will occur in any system4 ,such condensation cannot be wholly overcome and if the water of condensation is carried to the prime mover1 difficulties will invariably result4 ,water is practically incompressible and its effect when traveling at high velocities differs little from that of a solid body of equal weight1 hence impact against elbows1 valves or other obstructions1 is the equivalent of a heavy hammer blow that may result in the fracture of the pipe4 ,if there is not sufficient water in the system to produce this result1 it will certainly cause knocking and vibration in the pipe1 resulting eventually in leaky joints4 ,where the water reaches the prime mover1 its effect will vary from disagreeable knocking to disruption4 ,too frequently when there are disastrous results from such a cause the boilers are blamed for delivering wet steam when1 as a matter of fact1 the evil is purely a result of poor piping design1 the most common cause of such an action being the pocketing of the water in certain parts of the piping from whence it is carried along in slugs by the steam4 ,the action is particularly severe if steam is admitted to a cold pipe containing water1 as the water may then form a partial vacuum by condensing the steam and be projected at a very high velocity through the pipes producing a characteristic sharp metallic knock which often causes bursting of the pipe or fittings4 ,the amount of water present through condensation may be appreciated when it is considered that uncovered #f-;inch pipe #aej feet long carrying #cfjj pounds of high pressure steam per hour will condense approximately #f per cent of the total steam carried through radiation4 ,it follows that efficient means of removing condensation water are absolutely imperative and the following suggestions as to such means may be of service3 ,the pitch of all pipe should be in the direction of the flow of steam4 ,wherever a rise is necessary1 a drain should be installed4 ,all main headers and important branches should end in a drop leg and each such drop leg and any low points in the system should be connected to the drainage pump4 ,a similar connection should be made to every fitting where there is danger of a water pocket4 ,branch lines should never be taken from the bottom of a main header but where possible should be taken from the top4 ,each engine supply pipe should have its own separator placed as near the throttle as possible4 ,such separators should be drained to the drainage system4 ,check valves are frequently placed in drain pipes to prevent steam from entering any portion of the system that may be shut off4 ,valves should be so located that they cannot form water pockets when either open or closed4 ,globe valves will form a water pocket in the piping to which they are connected unless set with the stem horizontal1 while gate valves may be set with the spindle vertical or at an angle4 ,where valves are placed directly on the boiler nozzle1 a drain should be provided above them4 ,high pressure drains should be trapped to both feed heaters and waste headers4 ,traps and meters should be provided with by-passes4 ,cylinder drains1 heater blow-offs and drains1 boiler blow-offs and similar lines should be led to waste4 ,the ends of cylinder drains should not extend below the surface of water1 for on starting up or on closing the throttle valve with the drains open1 water may be drawn back into the cylinders4 ,,table #fd ,,radiation ,,from ,,covered ,,and ,,uncovered ,,steam ,,pipes ,,calculated ,,for #afj ,,pounds ,,pressure ,,and #fj ,,degrees ,,temperature ---------------------------------------- ----------------------------- ---------------------------------------- -------------------- ,pipe #a_/b #c_/d #a #a-a_/da-a_/b ,inches ,thickness of ,covering inchinchinchinch inch ,bare ---------------------------------------- -------------------- ,b4 t4 u4 per lineal foot per hour #adi #aah #ii #hf #gi #eig ,b4 t4 u4 per square foot per hour #bdj #aij #afa #ach #abg #iei #b ,b4 t4 u4 per square foot per hour per one degree difference in temperature4#ggj4fac4eai4dde 4#daj #c4aih ---------------------------------------- -------------------- ,b4 t4 u4 per lineal foot per hour #bdg #aic #afj #aci #abc #ajhe ,b4 t4 u4 per square foot per hour #baj #afd #acf #aah #ajd #iba #d ,b4 t4 u4 per square foot per hour per one degree difference in temperature4#fgg4eib4dci4cha 4#cce #b4igj ---------------------------------------- -------------------- ,b4 t4 u4 per lineal foot per hour #ceb #bfi #bba #aij #afg #aeee ,b4 t4 u4 per square foot per hour #bjc #aee #abg #aaj #if #hig #f ,b4 t4 u4 per square foot per hour per one degree difference in temperature4#fee4ejj4daj4cee 4#caj #b4hi ---------------------------------------- -------------------- ,b4 t4 u4 per lineal foot per hour #ddc #ccg #bgf #bce #bjg #aiid ,b4 t4 u4 per square foot per hour #aif #adi #abb #ajd #ib #hhc #h ,b4 t4 u4 per square foot per hour per one degree difference in temperature4#fcb4dha4cid4cce 4#big #b4he ---------------------------------------- -------------------- ,b4 t4 u4 per lineal foot per hour #edi #daf #ccg #bhg #bej #bdfh ,b4 t4 u4 per square foot per hour #aie #adh #abj #ajb #hi #hgg #aj ,b4 t4 u4 per square foot per hour per one degree difference in temperature4#fbi4dgg4chg4cbi 4#bhg #b4hc ---------------------------------------- -------------------- ---------------------------------------- ----------------------------- ,covering--,magnesia1 canvas covered4 ,for calculating radiation for pressure and temperature other than #afj pounds1 and #fj degrees1 use ,b4 t4 u4 figures for one degree difference4 ,radiation from ,pipes--,the evils of the presence of condensed steam in piping systems have been thoroughly discussed above and in some of the previous articles4 ,condensation resulting from radiation1 while it cannot be wholly obviated1 can1 by proper installation1 be greatly reduced4 ,bare pipe will radiate approximately #c ,b4 t4 u4 per hour per square foot of exposed surface per one degree of difference in temperature between the steam contained and the external air4 ,this figure may be reduced to from #j4c to #j4d ,b4 t4 u4 for the same conditions by a #a inch insulating covering4 ,table #fd gives the radiation losses for bare and covered pipes with different thicknesses of magnesia covering4 ,many experiments have been made as to the relative efficiencies of different kinds of covering4 ,table #fe gives some approximately relative figures based on one inch covering from experiments by ,paulding1 ,jacobus1 ,brill and others4 ,,table #fe ,,approximate ,,efficiencies ,,of ,,various ,,coverings ,,referred ,,to ,,bare ,,pipes -------------------------------- ----------------------------- ,covering ,efficiency ----------------------------- ,asbestocel #gf4h ,gast's ,air ,cell #gd4d ,asbesto ,sponge ,felt #he4j ,magnesia #hc4e ,asbestos ,navy ,brand #hb4j ,asbesto ,sponge ,hair #hf4j ,asbestos ,fire ,felt #gc4e ----------------------------- -------------------------------- ,based on one-inch covering4 ,the following suggestions may be of service3 ,exposed radiating surfaces of all pipes1 all high pressure steam flanges1 valve bodies and fittings1 heaters and separators1 should be covered with non-conducting material wherever such covering will improve plant economy4 ,all main steam lines1 engine and boiler branches1 should be covered with #b inches of #he per cent carbonate of magnesia or the equivalent4 ,other lines may be covered with one inch of the same material4 ,all covering should be sectional in form and large surfaces should be covered with blocks1 except where such material would be difficult to install1 in which case plastic material should be used4 ,in the case of flanges the covering should be tapered back from the flange in order that the bolts may be removed4 ,all surfaces should be painted before the covering is applied4 ,canvas is ordinarily placed over the covering1 held in place by wrought-iron or brass bands4 ,expansion and ,support of ,pipe--,it is highly important that the piping be so run that there will be no undue strains through the action of expansion4 ,certain points are usually securely anchored and the expansion of the piping at other points taken care of by providing supports along which the piping will slide or by means of flexible hangers4 ,where pipe is supported or anchored1 it should be from the building structure and not from boilers or prime movers4 ,where supports are furnished1 they should in general be of any of the numerous sliding supports that are available4 ,expansion is taken care of by such a method of support and by the providing of large radius bends where necessary4 ,it was formerly believed that piping would actually expand under steam temperatures about one-half the theoretical amount due to the fact that the exterior of the pipe would not reach the full temperature of the steam contained4 ,it would appear1 however from recent experiments that such actual expansion will in the case of well-covered pipe be very nearly the theoretical amount4 ,in one case noted1 a steam header #bic feet long when heated under a working pressure of #aij pounds1 the steam superheated approximately #abe degrees1 expanded #h inches2 the theoretical amount of expansion under the conditions would be approximately #i-ce_/fd inches4 ,illustration3 ,bankers ,trust ,building1 ,new ,york ,city1 ,operation #ijj ,horse ,power of ,babcock ,wilcox ,boilers ,,flow ,,of ,,steam ,,through ,,pipes ,,and ,,orifices ,various formulae for the flow of steam through pipes have been advanced1 all having their basis upon ,bernoulli's theorem of the flow of water through circular pipes with the proper modifications made for the variation in constants between steam and water4 ,the loss of energy due to friction in a pipe is given by ,unwin 7based upon ,weisbach7 as f #b v ,w ,l ,ef ---------- 7#cg7 gd where ,e is the energy loss in foot pounds due to the friction of ,w units of weight of steam passing with a velocity of v feet per second through a pipe d feet in diameter and ,l feet long2 g represents the acceleration due to gravity 7#cb4b7 and f the coefficient of friction4 ,numerous values have been given for this coefficient of friction1 f1 which1 from experiment1 apparently varies with both the diameter of pipe and the velocity of the passing steam4 ,there is no authentic data on the rate of this variation with velocity and1 as in all experiments1 the effect of change of velocity has seemed less than the unavoidable errors of observation1 the coefficient is assumed to vary only with the size of the pipe4 ,unwin established a relation for this coefficient for steam at a velocity of #ajj feet per second1 _/ #c f ,k #a --- 7#ch7 #aj;d _/ where ,k is a constant experimentally determined1 and d the internal diameter of the pipe in feet4 ,if h represents the loss of head in feet1 then f #b v ,w ,l ,ef ,wh ---------- 7#ci7 gd f #b v ,l and h -------- 7#dj7 gd ,if ,d represents the density of the steam or weight per cubic foot1 and p the loss of pressure due to friction in pounds per square inch1 then h,d p --- 7#da7 #add and from equations 7#ch71 7#dj7 and 7#da71 ,d v ,l _/ #c p -------- ,k #a --- 7#db7 #gb g d #aj;d _/ ,to convert the velocity term and to reduce to units ordinarily used1 let d#a the diameter of pipe in inches #ab;d1 and w the flow in pounds per minute2 then pi _/ d#a w #fjv --- ---- #b ,d #d #ab _/ #i4f w and v -------------- pi d#ab ,d ,substituting this value and that of d in formula 7#db7 _/ #c4f w#b ,l p #j4jdhci ,k #a ----- ----------- 7#dc7 d#a _/ ,d d#ae ,some of the experimental determinations for the value of ,k are3 ,k 4#jje for water 7,unwin74 ,k 4#jje for air 7,arson74 ,k 4#jjbh for air 7,st4 ,gothard tunnel experiments74 ,k 4#jjbf for steam 7,carpenter at ,oriskany74 ,k 4#jjbg for steam 7,g4 ,h4 ,babcock74 ,the value 4#jjbg is apparently the most nearly correct1 and substituting in formula 7#dc7 gives1 _/ #c4f w#b ,l p #j4jjjaca #a ---- ----------- 7#dd7 d#a_/ ,d d#ae _/ p,dd#ae w #hg -------------- 7#de7 _/ #c4f #a ---- ,l d#a_/ _/ ,where w the weight of steam passing in pounds per minute1 p the difference in pressure between the two ends of the pipe in pounds per square inch1 ,d density of steam or weight per cubic foot1#hj d#a internal diameter of pipe in inches1 ,l length of pipe in feet4 ,,table #ff ,,flow ,,of ,,steam ,,through ,,pipes ---------------------------------------- ---------------------------------------- ------- ,initl,diameter#ha of ,pipe in ,inches1 ,length of ,pipe #bdj ,diameters ,gauge---------------------------------- ---------------------------------------- ------- ,press #a #a #b #b #c #d #e #f #h #aj #ab #ae #ah ,pound---------------------------------- ---------------------------------------- ------- _/,sq,in ,weight of ,steam per ,minute1 in ,pounds1 ,with ,one ,pound ,loss of ,pressure ---------------------------------------- ---------------------------------------- ------ #a #a4afb4jg #e4gaj4bgae4debe4ch #df4he #gg4caae4ibaa4d #cda4a #ejb4d #hjdaagg #aj #a4ddb4eg #g4aab4gbai4aeca4de #eh4je #ie4hadc4fbfb4j #dbb4g #fbb4e #iifadeh #bj #a4gjc4jb #h4cad4idbb4dicf4id #fh4bjaab4fafh4gcjg4h #dif4e #gca4caagjagac #cj #a4iac4dj #i4daf4hdbe4ceda4fc #gf4hdabf4iaij4acdf4h #eei4e #hbd4aacahaicj #dj #b4ajc4gdaj4cah4eabg4hgde4gg #hd4diaci4ebji4jcha4c #fae4c #ijf4jadejbabb #ej #b4bgd4jdaa4bbj4jacj4acdi4dh #ia4cdaej4hbbf4jdab4b #ffe4j #igi4eaefgbbid #fj #b4dcd4cbaa4iba4chcb4aieb4hg #ig4fjafa4abda4eddj4e #gaj4fajdf4gafgebdea #gj #b4egd4ehab4fbb4fecd4ajef4jjajc4cgagj4gb ee4hdff4e #geb4gaajh4eaggdbeif #hj #b4gad4hbac4cbc4hbce4hgeh4iaajh4gdagi4eb fi4jdij4g #gia4gaaff4aahffbgca #ij #b4hce4jdac4ibd4ibcg4ebfa4fbaac4gdahg4hb ha4deac4c #hbh4aabai4haieabhef #ajj #b4iee4bead4ebe4ifci4jgfd4ahaah4dgaie4fb ic4aecd4f #hfb4fabgj4abjcbbige #abj #c4afe4fcae4ebg4heda4icfh4hgabg4abbji4ic ad4eegc4g #ibe4facfc4cbahacaic #aej #c4def4adag4jcj4cgde4gbge4jiach4fabbh4hc dc4jfbe4eajji4badhf4ebcghcdha ---------------------------------------- ---------------------------------------- ------- ,this formula is the most generally accepted for the flow of steam in pipes4 ,table #ff is calculated from this formula and gives the amount of steam passing per minute that will flow through straight smooth pipes having a length of #bdj diameters from various initial pressures with one pound difference between the initial and final pressures4 ,to apply this table for other lengths of pipe and pressure losses other than those assumed1 let ,l the length and d the diameter of the pipe1 both in inches2 l1 the loss in pounds2 ,q1 the weight under the conditions assumed in the table1 and ,q#a1 the weight for the changed conditions4 ,for any length of pipe1 if the weight of steam passing is the same as given in the table1 the loss will be1 ,l l ---- 7#df7 #bdj;d ,if the pipe length is the same as assumed in the table but the loss is different1 the quantity of steam passing per minute will be1 ,q#a ,ql 7#dg7 ,for any assumed pipe length and loss of pressure1 the weight will be1 _/#bdj;dl ,q#a ,q----- 7#dh7 ,l _/ ,,table #fg ,,flow ,,of ,,steam ,,through ,,pipes ,,length ,,of ,,pipe #ajjj ,,feet ---------------------------------------- ---------------------------------------- ---------- ,discharge in ,pounds per ,minute corresponding to ,drop in ,pressure in ,drop in ,pressure on ,right for ,pipe ,diameters ,pounds per ,square ,inch corresponding in ,inches in ,top ,line to ,discharge on ,left3 ,densities and corresponding ,absolute ,pressures per ,square ,inch in ,first ,two ,lines ---------------------------------------- ---------------------------------------- ---------- ,diameter#hb--;,discharge ,density--,pressure--,drop ---------------------------------------- ---------------------------------------- ---------- #ab #aj #h #f #d #c #b #b #a #a 4#bjh 4#bcj4bhd4cbh4dja4ddc4ejf4edh ,in ,in ,in ,in ,in ,in ,in ,in ,in ,in #ij #ajj #abe #aej #ahj #bjj #bcj #bej ---------------------------------------- ---------------------------------------- --------- #bcbhaddc #gii #cgaabc4 #ee4ibh4hah4af4hab4ebah4ajaf4dac4caa4ai4 cih4ejg4ddf4hg #bafeacda #gdb #cddaad4fea4ibg4faf4hf4ebb4cdae4fjad4aaa 4di4fjh4jig4ccf4dae4ib #aiifabcg #fhe #cahajf4jdg4ibf4dae4ef4bdb4afac4c #ab4ji4gdh4ahf4ijf4bde4dge4je #ahcjaacd #fbh #bib #ig4jdc4ibe4bad4be4iea4ihaa4a #aj4jh4acf4hce4gfe4bad4efd4ba #affcajca #ega #bfe #hh4bci4ibd4jab4ie4fga4hj #i4beh4cff4ghe4fid4hjd4cdc4hjc4ea #aehj #igi #edb #beb #hc4hcg4ibb4hab4ce4bia4ga #h4ccg4ecf4aje4acd4cbc4iac4dbc4af #adig #ibh #ead #bci #gi4dce4iba4faa4fe4jja4fb #g4dhf4gfe4dhd4fjc4hhc4eac4jgb4hd #adad #hgf #dhe #bbf #ge4jcc4ibj4daj4id4gba4ec #f4fgf4jcd4hhd4ajc4dfc4acb4gdb4ec #acca #hbe #deg #bab #gj4fca4iai4baj4cd4dca4dd #e4iae4ced4ccc4fdc4jgb4ghb4dcb4bd #abdh #hgc #dbh #aii #ff4bbc4iah4ji4fhd4aea4ce #e4aid4fic4hjc4aib4fib4ddb4aca4ig #aafd #gbb #djj #ahf #fa4gbg4iaf4hi4jcc4hfa4bf #d4ebd4jic4cab4ghb4cdb4aba4hfa4gb #ajha #fgj #cga #agb #eg4cbe4iae4fh4chc4fha4ag #c4ijc4ecb4hfb4djb4jba4hca4fja4dh #iih #fai #cdc #aei #eb4ibc4iad4dg4gdc4dja4jh #c4cbc4jjb4dcb4jda4gba4efa4cfa4bf #iae #efg #cad #adf #dh4eba4iac4bg4ajc4aaj4ii #b4gib4ebb4jda4gba4dea4caa4aea4jf #hcb #eaf #bhf #acb #dd4abj4jab4jf4deb4hcj4ij #b4cab4jia4fia4dba4bja4jh4idi4hgg #gdh #dfd #beg #aai #ci4gah4jaj4he4hab4eej4ha #a4hga4fia4cga4ae 4#ig4hgh4gfi4gaj #ffe #dab #bbh #ajf #ce4caf4j #i4fe4afb4bfj4gb #a4dga4cca4jh4ije4gfb4fij4fjd4eeh #ehb #cfa #bjjib4h #cj4iad4j #h4dd4eba4ihj4fc #a4aca4jb4hbh4fie4ehf4eca4def4dbi ---------------------------------------- ---------------------------------------- ---------- ,to get the pressure drop for lengths other than #ajjj feet1 multiply by lengths in feet #ajjj4 ,example3 ,find the weight of steam at #ajj pounds initial gauge pressure1 which will pass through a #f-;inch pipe #gbj feet long with a pressure drop of #d pounds4 ,under the conditions assumed in the table1 #bic4a pounds would flow per minute2 hence1 ,q #bic4a1 and #bdjfd ,q#a #bic4a ------- #bci4i pounds #gbjab ,table #fg may be frequently found to be of service in problems involving the flow of steam4 ,this table was calculated by ,mr4 ,e4 ,c4 ,sickles for a pipe #ajjj feet long from formula 7#de71 except that from the use of a value of the constant ,k 4#jjbf instead of 4#jjbg1 the constant in the formula becomes #hg4de instead of #hg4 ,in using this table1 the pressures and densities to be considered1 as given at the top of the right-hand portion1 are the mean of the initial and final pressures and densities4 ,its use is as follows3 ,assume an allowable drop of pressure through a given length of pipe4 ,from the value as found in the right-hand column under the column of mean pressure1 as determined by the initial and final pressures1 pass to the left-hand portion of the table along the same line until the quantity is found corresponding to the flow required4 ,the size of the pipe at the head of this column is that which will carry the required amount of steam with the assumed pressure drop4 ,the table may be used conversely to determine the pressure drop through a pipe of a given diameter delivering a specified amount of steam by passing from the known figure in the left to the column on the right headed by the pressure which is the mean of the initial and final pressures corresponding to the drop found and the actual initial pressure present4 ,for a given flow of steam and diameter of pipe1 the drop in pressure is proportional to the length and if discharge quantities for other lengths of pipe than #ajjj feet are required1 they may be found by proportion4 ,,table #fh ,,flow ,,of ,,steam ,,into ,,the ,,atmosphere ,absolute ,velocity ,actual ,discharge ,horse ,power ,initial of ,outflow ,velocity per ,square per ,square ,pressure at ,constant of ,outflow ,inch of ,inch of per ,square ,density ,expanded ,orifice ,orifice if ,inch ,feet per ,feet per per ,minute ,horse ,power ,pounds ,second ,second ,pounds #cj ,pounds per ,hour #be4cg #hfc #adja #bb4ha #de4f #cj4 #hfg #adjh #bf4hd #ec4g #dj4 #hgd #adai #ce4ah #gj4d #ej4 #hhj #adbi #dd4jf #hh4a #fj4 #hhe #adcg #eb4ei #aje4b #gj4 #hhi #addd #fa4jg #abb4a #ge4 #hia #addg #fe4cj #acj4f #ij4 #hie #aded #gg4id #aee4i #ajj4 #hih #adei #hf4cd #agb4g #aae4 #ijb #adff #ih4gf #aig4e #ace4 #ijf #adgb #aae4fa #bca4b #aee4 #iaj #adgh #acb4ba #bfd4d #afe4 #iab #adha #adj4df #bhj4i #bae4 #iai #adic #aha4eh #cfc4b ,elbows1 globe valves and a square-ended entrance to pipes all offer resistance to the passage of steam4 ,it is customary to measure the resistance offered by such construction in terms of the diameter of the pipe4 ,many formulae have been advanced for computing the length of pipe in diameters equivalent to such fittings or valves which offer resistance4 ,these formulae1 however vary widely and for ordinary purposes it will be sufficiently accurate to allow for resistance at the entrance of a pipe a length equal to #fj times the diameter2 for a right angle elbow1 a length equal to #dj diameters1 and for a globe valve a length equal to #fj diameters4 ,the flow of steam of a higher toward a lower pressure increases as the difference in pressure increases to a point where the external pressure becomes #eh per cent of the absolute initial pressure4 ,below this point the flow is neither increased nor decreased by a reduction of the external pressure1 even to the extent of a perfect vacuum4 ,the lowest pressure for which this statement holds when steam is discharged into the atmosphere is #be4cg pounds4 ,for any pressure below this figure1 the atmospheric pressure1 #ad4g pounds1 is greater than #eh per cent of the initial pressure4 ,table #fh1 by ,d4 ,k4 ,clark1 gives the velocity of outflow at constant density1 the actual velocity of outflow expanded 7the atmospheric pressure being taken as #ad4g pounds absolute1 and the ratio of expansion in the nozzle being #a4fbd71 and the corresponding discharge per square inch of orifice per minute4 ,napier deduced an approximate formula for the outflow of steam into the atmosphere which checks closely with the figures just given4 ,this formula is3 pa ,w ---- 7#di7 #gj ,where ,w the pounds of steam flowing per second1 p the absolute pressure in pounds per square inch1 and a the area of the orifice in square inches4 ,in some experiments made by ,professor ,c4 ,h4 ,peabody1 in the flow of steam through pipes from inch to #a inches long and inch in diameter1 with rounded entrances1 the greatest difference from ,napier's formula was #c4b per cent excess of the experimental over the calculated results4 ,for steam flowing through an orifice from a higher to a lower pressure where the lower pressure is greater than #eh per cent of the higher1 the flow per minute may be calculated from the formula3 ,w #a4i;,,ak 77,p - d7d7 7#ej7 ,where ,w the weight of steam discharged in pounds per minute1 ,a area of orifice in square inches1 ,p the absolute initial pressure in pounds per square inch1 d the difference in pressure between the two sides in pounds per square inch1 ,k a constant 4#ic for a short pipe1 and 4#fc for a hole in a thin plate or a safety valve4 ,illustration3 ,vesta ,coal ,co41 ,california1 ,pa41 ,operating at this ,plant #cafj ,horse ,power of ,babcock ,wilcox ,boilers ,,heat ,,transfer ,the rate at which heat is transmitted from a hot gas to a cooler metal surface over which the gas is flowing has been the subject of a great deal of investigation both from the experimental and theoretical side4 ,a more or less complete explanation of this process is necessary for a detailed analysis of the performance of steam boilers4 ,such information at the present is almost entirely lacking and for this reason a boiler1 as a physical piece of apparatus1 is not as well understood as it might be4 ,this1 however1 has had little effect in its practical development and it is hardly possible that a more complete understanding of the phenomena discussed will have any radical effect on the present design4 ,the amount of heat that is transferred across any surface is usually expressed as a product1 of which one factor is the slope or linear rate of change in temperature and the other is the amount of heat transferred per unit's difference in temperature in unit's length4 ,in ,fourier's analytical theory of the conduction of heat1 this second factor is taken as a constant and is called the conductivity of the substance4 ,following this practice1 the amount of heat absorbed by any surface from a hot gas is usually expressed as a product of the difference in temperature between the gas and the absorbing surface into a factor which is commonly designated the transfer rate4 ,there has been considerable looseness in the writings of even the best authors as to the way in which the gas temperature difference is to be measured4 ,if the gas varies in temperature across the section of the channel through which it is assumed to flow1 and most of them seem to consider that this would be the case1 there are two mean gas temperatures1 one the mean of the actual temperatures at any time across the section1 and the other the mean temperature of the entire volume of the gas passing such a section in any given time4 ,since the velocity of flow will of a certainty vary across the section1 this second mean temperature1 which is one tacitly assumed in most instances1 may vary materially from the first4 ,the two mean temperatures are only approximately equal when the actual temperature measured across the section is very nearly a constant4 ,in what follows it will be assumed that the mean temperature measured in the second way is referred to4 ,in ,english units the temperature difference is expressed in ,fahrenheit degrees and the transfer rate in ,b4 t4 u4's per hour per square foot of surface4 ,pecla1 who seems to have been one of the first to consider this subject analytically1 assumed that the transfer rate was constant and independent both of the temperature differences and the velocity of the gas over the surface4 ,rankine1 on the other hand1 assumed that the transfer rate1 while independent of the velocity of the gas1 was proportional to the temperature difference1 and expressed the total amount of heat absorbed as proportional to the square of the difference in temperature4 ,neither of these assumptions has any warrant in either theory or experiment and they are only valuable in so far as their use determine formulae that fit experimental results4 ,of the two1 ,rankine's assumption seems to lead to formulae that more nearly represent actual conditions4 ,it has been quite fully developed by ,william ,kent in his ,steam ,boiler ,economy4 ,professor ,osborne ,reynolds1 in a short paper reprinted in ,volume ,i of his ,scientific ,papers1 suggests that the transfer rate is proportional to the product of the density and velocity of the gas and it is to be assumed that he had in mind the mean velocity1 density and temperature over the section of the channel through which the gas was assumed to flow4 ,contrary to prevalent opinion1 ,professor ,reynolds gave neither a valid experimental nor a theoretical explanation of his formula and the attempts that have been made since its first publication to establish it on any theoretical basis can hardly be considered of scientific value4 ,nevertheless1 ,reynolds' suggestion was really the starting point of the scientific investigation of this subject and while his formula cannot in any sense be held as completely expressing the facts1 it is undoubtedly correct to a first approximation for small temperature differences if the additive constant1 which in his paper he assumed as negligible1 is given a value4#hc ,experimental determinations have been made during the last few years of the heat transfer rate in cylindrical tubes at comparatively low temperatures and small temperature differences4 ,the results at different velocities have been plotted and an empirical formula determined expressing the transfer rate with the velocity as a factor4 ,the exponent of the power of the velocity appearing in the formula1 according to ,reynolds1 would be unity4 ,the most probable value1 however1 deduced from most of the experiments makes it less than unity4 ,after considering experiments of his own1 as well as experiments of others1 ,dr4 ,wilhelm ,nusselt#hd concludes that the evidence supports the following formulae3 lambdaw w cp delta a b ------------ --------------- u d#a-u lambda ,where a is the transfer rate in calories per hour per square meter of surface per degree centigrade difference in temperature1 u is a physical constant equal to 4#ghf from ,dr4 ,nusselt's experiments1 b is a constant which1 for the units given below1 is #ae4ij1 w is the mean velocity of the gas in meters per second1 cp is the specific heat of the gas at its mean temperature and pressure in calories per kilogram1 delta is the density in kilograms per cubic meter1 lambda is the conductivity at the mean temperature and pressure in calories per hour per square meter per degree centigrade temperature drop per meter1 lambdaw is the conductivity of the steam at the temperature of the tube wall1 d is the diameter of the tube in meters4 ,if the unit of time for the velocity is made the hour1 and in the place of the product of the velocity and density is written its equivalent1 the weight of gas flowing per hour divided by the area of the tube1 this equation becomes3 lambdaw ,wcp a 4#jbee ------------ --------- 4#ghf d4#bad ,alambda where the quantities are in the units mentioned1 or1 since the constants are absolute constants1 in ,english units1 a is the transfer rate in ,b4 t4 u4 per hour per square foot of surface per degree difference in temperature1 ,w is the weight in pounds of the gas flowing through the tube per hour1 ,a is the area of the tube in square feet1 d is the diameter of the tube in feet1 cp is the specific heat of the gas at constant pressure1 lambda is the conductivity of the gas at the mean temperature and pressure in ,b4 t4 u4 per hour per square foot of surface per degree ,fahrenheit drop in temperature per foot1 lambdaw is the conductivity of the steam at the temperature of the wall of the tube4 ,the conductivities of air1 carbonic acid gas and superheated steam1 as affected by the temperature1 in ,english units1 are3 ,conductivity of air 4#jabb 7#a 4#jjacb ,t7 ,conductivity of carbonic acid gas 4#jjgf 7#a 4#jjbbi ,t7 ,conductivity of superheated steam 4#jaai 7#a 4#jjbfa ,t7 where ,t is the temperature in degrees ,fahrenheit4 ,nusselt's formulae can be taken as typical of the number of other formulae proposed by ,german1 ,french and ,english writers4#he ,physical properties1 in addition to the density1 are introduced in the form of coefficients from a consideration of the physical dimensions of the various units and of the theoretical formulae that are supposed to govern the flow of the gas and the transfer of heat4 ,all assume that the correct method of representing the heat transfer rate is by the use of one term1 which seems to be unwarranted and probably has been adopted on account of the convenience in working up the results by plotting them logarithmically4 ,this was the method ,professor ,reynolds used in determining his equation for the loss in head in fluids flowing through cylindrical pipes and it is now known that the derived equation cannot be considered as anything more than an empirical formula4 ,it1 therefore1 is well for anyone considering this subject to understand at the outset that the formulae discussed are only of an empirical nature and applicable to limited ranges of temperature under the conditions approximately the same as those surrounding the experiments from which the constants of the formula were determined4 ,it is not probable that the subject of heat transfer in boilers will ever be on any other than an experimental basis until the mathematical expression connecting the quantity of fluid which will flow through a channel of any section under a given head has been found and some explanation of its derivation obtained4 ,taking the simplest possible section1 namely1 a circle1 it is found that at low velocities the loss of head is directly proportional to the velocity and the fluid flows in straight stream lines or the motion is direct4 ,this motion is in exact accordance with the theoretical equations of the motion of a viscous fluid and constitutes almost a direct proof that the fundamental assumptions on which these equations are based are correct4 ,when1 however1 the velocity exceeds a value which is determinable for any size of tube1 the direct or stream line motion breaks down and is replaced by an eddy or mixing flow4 ,in this flow the head loss by friction is approximately1 although not exactly1 proportional to the square of the velocity4 ,no explanation of this has ever been found in spite of the fact that the subject has been treated by the best mathematicians and physicists for years back4 ,it is to be assumed that the heat transferred during the mixing flow would be at a much higher rate than with the direct or stream line flow1 and ,professors ,croker and ,clement#hf have demonstrated that this is true1 the increase in the transfer being so marked as to enable them to determine the point of critical velocity from observing the rise in temperature of water flowing through a tube surrounded by a steam jacket4 ,the formulae given apply only to a mixing flow and inasmuch as1 from what has just been stated1 this form of motion does not exist from zero velocity upward1 it follows that any expression for the heat transfer rate that would make its value zero when the velocity is zero1 can hardly be correct4 ,below the critical velocity1 the transfer rate seems to be little affected by change in velocity and ,nusselt1#hg in another paper which mathematically treats the direct or stream line flow1 concludes that1 while it is approximately constant as far as the velocity is concerned in a straight cylindrical tube1 it would vary from point to point of the tube1 growing less as the surface passed over increased4 ,it should further be noted that no account in any of this experimental work has been taken of radiation of heat from the gas4 ,since the common gases absorb very little radiant heat at ordinary temperatures1 it has been assumed that they radiate very little at any temperature4 ,this may or may not be true1 but certainly a visible flame must radiate as well as absorb heat4 ,however this radiation may occur1 since it would be a volume phenomenon rather than a surface phenomenon it would be considered somewhat differently from ordinary radiation4 ,it might apply as increasing the conductivity of the gas which1 however independent of radiation1 is known to increase with the temperature4 ,it is1 therefore1 to be expected that at high temperatures the rate of transfer will be greater than at low temperatures4 ,the experimental determinations of transfer rates at high temperatures are lacking4 ,although comparatively nothing is known concerning the heat radiation from gases at high temperatures1 there is no question but what a large proportion of the heat absorbed by a boiler is received direct as radiation from the furnace4 ,experiments show that the lower row of tubes of a ,babcock ,wilcox boiler absorb heat at an average rate per square foot of surface between the first baffle and the front headers equivalent to the evaporation of from #ej to #ge pounds of water from and at #bab degrees ,fahrenheit per hour4 ,inasmuch as in these experiments no separation could be made between the heat absorbed by the bottom of the tube and that absorbed by the top1 the average includes both maximum and minimum rates for those particular tubes and it is fair to assume that the portion of the tubes actually exposed to the furnace radiations absorb heat at a higher rate4 ,part of this heat was1 of course absorbed by actual contact between the hot gases and the boiler heating surface4 ,a large portion of it1 however1 must have been due to radiation4 ,whether this radiant heat came from the fire surface and the brickwork and passed through the gases in the furnace with little or no absorption1 or whether1 on the other hand1 the radiation were absorbed by the furnace gases and the heat received by the boiler was a secondary radiation from the gases themselves and at a rate corresponding to the actual gas temperature1 is a question4 ,if the radiations are direct1 then the term furnace temperature1 as usually used has no scientific meaning1 for obviously the temperature of the gas in the furnace would be entirely different from the radiation temperature1 even were it possible to attach any significance to the term radiation temperature1 and it is not possible to do this unless the radiations are what are known as full radiations from a so-called black body4 ,if furnace radiation takes place in this manner1 the indications of a pyrometer placed in a furnace are hard to interpret and such temperature measurements can be of little value4 ,if the furnace gases absorb the radiations from the fire and from the brickwork of the side walls and in their turn radiate heat to the boiler surface1 it is scientifically correct to assume that the actual or sensible temperature of the gas would be measured by a pyrometer and the amount of radiation could be calculated from this temperature by ,stefan's law1 which is to the effect that the rate of radiation is proportional to the fourth power of the absolute temperature1 using the constant with the resulting formula that has been determined from direct experiment and other phenomena4 ,with this understanding of the matter1 the radiations absorbed by a boiler can be taken as equal to that absorbed by a flat surface1 covering the portion of the boiler tubes exposed to the furnace and at the temperature of the tube surface1 when completely exposed on one side to the radiations from an atmosphere at the temperature in the furnace4 ,with this assumption1 if ,s#a is the area of the surface1 ,t the absolute temperature of the furnace gases1 t the absolute temperature of the tube surface of the boiler1 the heat absorbed per hour measured in ,b4 t4 u4's is equal to _/ ,t _/ t #afjj ----#d - ----#d ,s#a #ajjj_/ #ajjj_/ ,in using this formula1 or in any work connected with heat transfer1 the external temperature of the boiler heating surface can be taken as that of saturated steam at the pressure under which the boiler is working1 with an almost negligible error1 since experiments have shown that with a surface clean internally1 the external surface is only a few degrees hotter than the water in contact with the inner surface1 even at the highest rates of evaporation4 ,further than this1 it is not conceivable that in a modern boiler there can be much difference in the temperature of the boiler in the different parts1 or much difference between the temperature of the water and the temperature of the steam in the drums which is in contact with it4 ,if the total evaporation of a boiler measured in ,b4 t4 u4's per hour is represented by ,e1 the furnace temperature by ,t#a1 the temperature of the gas leaving the boiler by ,t#b1 the weight of gas leaving the furnace and passing through the setting per hour by ,w1 the specific heat of the gas by ,c1 it follows from the fact that the total amount of heat absorbed is equal to the heat received from radiation plus the heat removed from the gases by cooling from the temperature ,t#a to the temperature ,t#b1 that _/ ,t _/ t ,e #afjj ----#d - ----#d ,s#a ,,wc7,t#a - ,t#b7 #ajjj_/ #ajjj_/ ,this formula can be used for calculating the furnace temperature when ,e1 t and ,t#b are known but it must be remembered that an assumption which is probably1 in part at least1 incorrect is implied in using it or in using any similar formula4 ,expressed in this way1 however1 it seems more rational than the one proposed a few years ago by ,dr4 ,nicholson#hh where1 in place of the surface exposed to radiation1 he uses the grate surface and assumes the furnace gas temperature as equal to the fire temperature4 ,if the heat transfer rate is taken as independent of the gas temperature and the heat absorbed by an element of the surface in a given time is equated to the heat given out from the gas passing over this surface in the same time1 a single integration gives ,rs 7,t - t7 7,t#a - t7 e- -- ,,wc where s is the area of surface passed over by the gases from the furnace to any point where the gas temperature ,t is measured1 and the rate of heat transfer is ,r4 ,as written1 this formula could be used for calculating the temperature of the gas at any point in the boiler setting4 ,gas temperatures1 however1 calculated in this way are not to be depended upon as it is known that the transfer rate is not independent of the temperature4 ,again1 if the transfer rate is assumed as varying directly with the weight of the gases passing1 which is ,reynolds' suggestion1 it is seen that the weight of the gases entirely disappears from the formula and as a consequence if the formula was correct1 as long as the temperature of the gas entering the surface from the furnace was the same1 the temperatures throughout the setting would be the same4 ,this is known also to be incorrect4 ,if1 however1 in place of ,t is written ,t#b and in place of s is written ,s1 the entire surface of the boiler1 and the formula is re-arranged1 it becomes3 ,,wc ,t#a - t ,r --- ,log#hi --------- ,s ,t#b - t ,this formula can be considered as giving a way of calculating an average transfer rate4 ,it has been used in this way for calculating the average transfer rate from boiler tests in which the capacity has varied from an evaporation of a little over #c pounds per square foot of surface up to #ae pounds4 ,when plotted against the gas weights1 it was found that the points were almost exactly on a line4 ,this line1 however1 did not pass through the zero point but started at a point corresponding to approximately a transfer rate of #b4 ,checked out against many other tests1 the straight line law seems to hold generally and this is true even though material changes are made in the method of calculating the furnace temperature4 ,the inclination of the line1 however1 varied inversely as the average area for the passage of the gas through the boiler4 ,if ,a is the average area between all the passes of the boiler1 the heat transfer rate in ,babcock ,wilcox type boilers with ordinary clean surfaces can be determined to a rather close approximation from the formula3 ,w ,r #b4jj 4#jjad - ,a ,the manner in which ,a appears in this formula is the same as it would appear in any formula in which the heat transfer rate was taken as depending upon the product of the velocity and the density of the gas jointly1 since this product1 as pointed out above1 is equivalent to ,w_/,a4 ,nusselt's experiments1 as well as those of others1 indicate that the ratio appears in the proper way4 ,while the underlying principles from which the formula for this average transfer rate was determined are questionable and at best only approximately correct1 it nevertheless follows that assuming the transfer rate as determined experimentally1 the formula can be used in an inverse way for calculating the amount of surface required in a boiler for cooling the gases through a range of temperature covered by the experiments and it has been found that the results bear out this assumption4 ,the practical application of the theory of heat transfer1 as developed at present1 seems consequently to rest on these last two formulae1 which from their nature are more or less empirical4 ,through the range in the production of steam met with in boilers now in service which in the marine type extends to the average evaporation of #ab to #ae pounds of water from and at #bab degrees ,fahrenheit per square foot of surface1 the constant #b in the approximate formula for the average heat transfer rate constitutes quite a large proportion of the total4 ,the comparative increase in the transfer rate due to a change in weight of the gases is not as great consequently as it would be if this constant were zero4 ,for this reason1 with the same temperature of the gases entering the boiler surface1 there will be a gradual increase in the temperature of the gases leaving the surface as the velocity or weight of flow increases and the proportion of the heat contained in the gases entering the boiler which is absorbed by it is gradually reduced4 ,it is1 of course1 possible that the weight of the gases could be increased to such an amount or the area for their passage through the boiler reduced by additional baffles until the constant term in the heat transfer formula would be relatively unimportant4 ,under such conditions1 as pointed out previously1 the final gas temperature would be unaffected by a further increase in the velocity of the flow and the fraction of the heat carried by the gases removed by the boiler would be constant4 ,actual tests of waste heat boilers in which the weight of gas per square foot of sectional area for its passage is many times more than in ordinary installations show1 however1 that this condition has not been attained and it will probably never be attained in any practical installation4 ,it is for this reason that the conclusions of ,dr4 ,nicholson in the paper referred to and of ,messrs4 ,kreisinger and ,ray in the pamphlet ,the ,transmission of ,heat into ,steam ,boilers1 published by the ,department of the ,interior in #aiab1 are not applicable without modification to boiler design4 ,in superheaters the heat transfer is effected in two different stages2 the first transfer is from the hot gas to the metal of the superheater tube and the second transfer is from the metal of the tube to the steam on the inside4 ,there is1 theoretically1 an intermediate stage in the transfer of the heat from the outside to the inside surface of the tube4 ,the conductivity of steel is sufficient1 however1 to keep the temperatures of the two sides of the tube very nearly equal to each other so that the effect of the transfer in the tube itself can be neglected4 ,the transfer from the hot gas to the metal of the tube takes place in the same way as with the boiler tubes proper1 regard being paid to the temperature of the tube which increases as the steam is heated4 ,the transfer from the inside surface of the tube to the steam is the inverse of the process of the transfer of the heat on the outside and seems to follow the same laws4 ,the transfer rate1 therefore1 will increase with the velocity of the steam through the tube4 ,for this reason1 internal cores are quite often used in superheaters and actually result in an increase in the amount of superheat obtained from a given surface4 ,the average transfer rate in superheaters based on a difference in mean temperature between the gas on the outside of the tubes and the steam on the inside of the tubes is if ,r is the transfer rate from the gas to the tube and r the rate from the tube to the steam3 ,rr ----- ,r r and is always less than either ,r or r4 ,this rate is usually greater than the average transfer rate for the boiler as computed in the way outlined in the preceding paragraphs4 ,since1 however1 steam cannot1 under any imagined set of conditions1 take up more heat from a tube than would water at the same average temperature1 this fact supports the contention made that the actual transfer rate in a boiler must increase quite rapidly with the temperatures4 ,the actual transfer rates in superheaters are affected by so many conditions that it has not so far been possible to evolve any formula of practical value4 ,illustration3 ,iron ,city ,brewery of the ,pittsburgh ,brewing ,co41 ,pittsburgh1 ,pa1 ,operating in this ,plant #bjjj ,horse ,power of ,babcock ,wilcox ,boilers ,,index ,,page ,absolute pressure #aag ,absolute zero #hj ,accessibility of ,babcock ,wilcox boiler #ei ,acidity in boiler feed water #ajf ,actual evap4 corresponding to boiler horse power #bhh ,advantages of ,babcock ,wilcox boilers #fa ,stoker firing #aie ,water tube over fire tube boilers #fa ,air1 composition of #adg ,in boiler feed water #ajf ,properties of #adg ,required for combustion #aeb1 #aef ,specific heat of #adh ,supplied for combustion #aeg ,vapor in #adi ,volume of #adg ,weight of #adg ,alkalinity in boiler feed water #ajc ,testing feed for #ajc ,altitude1 boiling point of water at #ig ,chimney sizes corrected for #bdh ,alum in feed water treatment #ajf ,a4 ,s4 ,m4 ,e4 code for boiler testing #bfg ,analyses1 comparison of proximate and ultimate #ahc ,proximate coal1 and heating values #agg ,analysis1 coal1 proximate1 methods of #agf ,coal1 ultimate #agc ,determination of heating value from #agc ,analysis1 ,flue gas #aee ,flue gas1 methods of #afj ,flue gas1 object of #aee ,anthracite coal #aff ,combustion rates with #bdf ,distribution of #afg ,draft required for #bdf ,firing #aij ,grate ratio for #aia ,semi #aff ,sizes of #aij ,steam as aid to burning #aia ,thickness of fires with #aia ,arches1 fire brick1 as aid to combustion #aij ,fire brick1 for #cjd ,fire brick1 laying #cje ,automatic stokers1 advantages of #aie ,overfeed #aif ,traveling grate #aig ,traveling grate1 ,babcock ,wilcox #aid ,underfeed #aif ,auxiliaries1 exhaust from1 in heating feed water #aac ,superheated steam with #adb ,auxiliary grates1 with blast furnace gas #bbh ,with oil fuel #bbe ,with waste heat #bce ,babcock1 ,g4 ,h41 lecture on circulation of water in ,boilers #bh ,lecture on theory of steam making #ib ,babcock ,wilcox ,co41 ,works at ,barberton1 ,ohio #g ,works at ,bayonne1 ,n4 ,j4 #f ,babcock ,wilcox boiler1 accessibility of #ei ,advantages of #fa ,circulation of water in #eg1 #ff ,construction of #di ,cross boxes #ej ,cross drum #ec ,cross drum1 dry steam with #ga ,drumheads #di ,drums #di ,durability #ge ,evolution of #ci ,fittings #ee ,fixtures #ee ,fronts #ec ,handhole fittings #ej1 #ea ,headers #ej1 #ea ,inclined header1 wrought steel #ed ,inspection #ge ,life of #gf ,materials entering into the construction of #ei ,mud drums #ea ,path of gases in #eg ,path of water in #eg ,rear tube doors of #ec1 #gd ,repairs #ge ,safety of #ff ,sections #ej ,set for utilizing waste heat #bcf ,set with ,babcock ,wilcox chain grate stoker #ab ,set with bagasse furnace #bjh ,set with ,peabody oil furnace #bbb ,supports1 cross drum #ec ,supports1 longitudinal drum #eb ,tube doors #ec ,vertical header1 cast iron #eh ,vertical header1 wrought steel #dh ,babcock ,wilcox chain grate stoker #aid ,babcock ,wilcox superheater #acf ,bagasse1 composition of #bjf ,furnace #bji ,heat1 value of #bjf ,tests of ,babcock ,wilcox boilers with #baj ,value of diffusion #bjg ,barium carbonate in feed water treatment #ajf ,barium hydrate in feed water treatment #ajf ,barrus draft gauge #bed ,bituminous coal1 classification of #afg ,combustion rates with #bdf ,composition of #agg ,distribution of #afh ,firing methods #aic ,semi #aff ,sizes of #aia ,thickness of fire with #aic ,blast furnace gas1 burners for #bbh ,combustion of #bbh ,composition of #bbg ,stacks for #bbh ,boiler1 ,blakey's #bc ,brickwork1 care of #cjg ,circulation of water in steam #bh ,compounds #aji ,development of water tube #bc ,eve's #bd ,evolution of ,babcock ,wilcox #ci ,fire tube1 compared with water tube #fa ,guerney's #bd ,horse power #bfc ,loads1 economical #bhc ,perkins' #bd ,room piping #ajh ,room practice #big ,rumsey's #bc ,stevens'1 ,john #bc ,stevens'1 ,john ,cox #bc ,units1 number of #bhi ,units1 size of #bhi ,wilcox's #be ,woolf's #bc ,boilers1 capacity of #bgh ,care of #bia ,efficiency of #bef ,horse power of #bfe ,operation of #bia ,requirements of steam #bg ,testing #bfg ,boiling point #hf ,of various substances #hf ,of water as affected by altitude #ig ,brick1 fire #cjd ,arches #cje ,classification of #cjd ,compression of #cjc ,expansion of #cjc ,hardness of #cjc ,laying up #cje ,nodules1 ratio of #cjc ,nodules1 size of #cjc ,plasticity of #cjb ,brick1 red #cjb ,brickwork1 care of #cjg ,british thermal unit #hc ,burners1 blast furnace gas #bbh ,by-product coke oven gas #bca ,natural gas #bca ,oil #bag ,oil1 capacity of #bba ,oil1 mechanical atomizing #bai ,oil1 operation of #bbc ,oil1 steam atomizing #bah ,oil1 steam consumption of #bbj ,burning hydrogen1 loss due to moisture formed in #bfa ,by-product coke oven gas burners #bca ,by-product coke oven gas1 combustion of #bca ,by-product coke oven gas1 composition and heat value of #bca ,calorie #hc ,calorific value 7see ,heat value74 ,calorimeter1 coal1 ,mahler bomb #ahd ,mahler bomb1 method of correction #ahg ,mahler bomb1 method of operation of #ahe ,calorimeter1 steam1 compact type of throttling #acb ,correction for #aca ,location of nozzles for #acd ,normal reading #aca ,nozzles #acd ,separating #acc ,throttling #abi ,capacity of boilers #bfd1 #bgh ,as affecting economy #bgf ,economical loads #bhc ,with bagasse #baj ,with blast furnace gas #bbh ,with coal #bhj ,with oil fuel #bbd ,capacity of natural gas burners #bbi ,capacity of oil burners #bba ,carbon dioxide in flue gases #aed ,unreliability of readings taken alone #afb ,carbon1 fixed #afe ,incomplete combustion of1 loss due to #aeh ,monoxide1 heat value of #aea ,monoxide1 in flue gases #aee ,unconsumed in ash1 loss due to #bfa ,care of boilers when out of service #cjj ,casings1 boilers #cjg ,causticity of feed water #ajc ,testing for #aje ,celsius thermometer scale #gi ,centigrade thermometer scale #gi ,chain grate stoker1 ,babcock ,wilcox #aid ,chemicals required in feed water treatment #aje ,chimney gases1 losses in #aeh1 #aei ,chimneys 7see ,draft74 ,correction in dimensions for altitude #bdh ,diameter of #bdc ,draft available from #bda ,draft loss in #bci ,for blast furnace gas #bec ,for oil fuel #bea ,for wood fuel #bed ,height of #bdc ,horse power they will serve #bej ,circulation of water in ,babcock ,wilcox boilers #eg1 #ff ,of water in steam boilers #bh ,results of defective #fb1 #ff1 #fg ,classification of coals #aff ,fire brick #cjd ,feed water difficulties #ajj ,fuels #afe ,cleaners1 turbine tube #bii ,cleaning1 ease of1 ,babcock ,wilcox boilers #gc ,closed feed water heaters #aaa ,coal1 ,alaska #afi ,analyses and heat value #agg ,analysis1 proximate #agf ,analysis1 ultimate #agc ,anthracite #aff ,bituminous #afg ,cannel #afg ,classification of #afe1 #aff ,combustion of #aij ,comparison with oil #bad ,consumption1 increase due to superheat #aci ,distribution of #afg ,formation of #afe ,lignite #afg ,records #bic ,semi-anthracite #aff ,semi-bituminous #aff ,sizes of anthracite #aij ,sizes of bituminous #aia ,code of ,a4 ,s4 ,m4 ,e4 for boiler testing #bfg ,coefficient of expansion of various substances #hg ,coke #aga ,oven gas1 by-product1 burners #bca ,oven gas1 by-product1 combustion of #bca ,oven gas1 by-product1 composition and heat value of #bca ,coking method of firing #aie ,color as indication of temperature #ia ,combination furnaces #bbd ,combustible in fuels #aej ,combustion #aej ,air required for #aeb1 #aef ,air supplied for #aeg ,combustion of coal #aij ,of gaseous fuels #bbg ,of liquid fuels #bab ,of solid fuels other than coal #bja ,composition of bagasse #bje ,blast furnace gas #bbg ,by-product coke oven gas #bca ,coals #agg ,natural gas #bbi ,oil #bac ,wood #bja ,compounds1 boiler #aji ,compressibility of water #ig ,compression of fire brick #cjc ,condensation1 effect of superheated steam on #adj ,in steam pipes #cac ,consumption1 heat1 of engines #ada ,correction1 stem1 for thermometers #hj ,for normal reading in steam calorimeter #aca ,for radiation1 bomb calorimeter #ahg ,corrosion #aja1 #ajf ,coverings1 pipe #cae ,cross drum1 ,babcock ,wilcox boiler #eb1 #ec1 #fj ,dry steam with #ga ,draft area as affecting economy in ,babcock ,wilcox boilers #gj ,available from chimneys #bda ,draft loss in chimneys #bci ,loss in boilers #bde ,loss in flues #bdc ,loss in furnaces #bde ,draft required for anthracite #bdf ,required for various fuels #bdf ,drums1 ,babcock ,wilcox1 cross #ec ,cross1 boxes #ej ,heads #di ,longitudinal #di ,manholes #di ,nozzles on #ej ,dry steam in ,babcock ,wilcox boilers #ga ,density of gases #adg ,steam #aae ,dulong's formula for heating value #agc ,ebullition1 point of #hf ,economizers #aaa ,efficiency of boilers1 chart of #beh ,combustible basis #bef ,dry coal basis #bef ,increase in1 due to superheaters #aci ,losses in 7see ,heat balance7 #bei ,testing #bfg ,test vs4 operating #bgh ,variation in1 with capacity #bhd ,with coal #bhh ,with oil #bbd ,ellison draft gauge #bed ,engine1 ,hero's #ac ,engines1 superheated steam with #ada ,equivalent evaporation from and at #bab degrees #aaf ,eve's boiler #bd ,evolution of ,babcock ,wilcox boiler #ci ,exhaust steam from auxiliaries #aac ,expansion1 coefficient of #hg ,of fire brick #cjc ,of pipe #cae ,pyrometer #hi ,factor of evaporation #aag ,fahrenheit thermometer scale #gi ,fans1 use of1 in waste heat work #bcc ,feed water1 air in #ajf ,as affecting capacity #bgi ,boiler #ajj ,feed water heaters1 closed #aaa ,economizers #aaa ,open #aaa ,feed water heating1 methods of #aaa ,saving by #aaj ,feed water1 impurities in #ajj ,lines #cab ,method of feeding #aaj ,feed water treatment #ajb ,chemical #ajb ,chemical1 lime and soda process #ajb ,chemical1 lime process #ajb ,chemical1 soda process #ajb ,chemicals used in lime and soda process #aje ,combined heat and chemical #aje ,heat #ajb ,less usual reagents #ajf ,firing1 advantages of stoker #aie ,methods for anthracite #aij ,bituminous #aic ,lignite #aie ,fittings1 handhole in ,babcock ,wilcox boilers #ej1 #ea ,pipe #caa ,superheated steam #ade ,with ,babcock ,wilcox boilers #ee ,fixtures with ,babcock ,wilcox boilers #ee ,flanges1 pipe #cji ,flow of steam into pressure above atmosphere #cag ,into the atmosphere #cbh ,through orifices #cag ,through pipes #cag ,flue gas analysis #aee ,conversion of volumetric to weight #afa ,methods of making #afj ,object of #aee ,orsat apparatus #aei ,flue gas1 composition of #aee ,losses in #aeh1 #aei ,weight per pound of carbon in fuel #aeh ,weight per pound of fuel #aeh ,weight resulting from combustion #aeg ,foaming #ajb1 #ajg ,fuel analysis1 proximate #agf ,ultimate #agc ,fuel calorimeter1 ,mabler bomb #ahd ,tests1 method of making #ahf ,fuels1 classification of #afe ,gaseous1 and their combustion #bbg ,fuels1 liquid1 and their combustion #bab ,solid1 coal #aij ,solid1 other than coal #bja ,furnace1 bagasse #bji ,blast furnace gas #bbh ,by-product coke oven gas #bca ,combination wood and oil #bbe ,efficiency of #bhc ,natural gas #bbi ,peabody oil #bbb ,webster #ee ,wood burning #bja1 #bjb ,galvanic action #ajg ,gas1 blast furnace1 burners #bbh ,combustion of #bbh ,composition of #bbg ,gas1 by-product coke oven1 burners #bca ,combustion of #bca ,composition of and heat value #bca ,gas1 natural1 burners #bbi ,combustion of #bbi ,composition and heat value of #bbi ,gases1 chimney1 losses in #aeh1 #aei ,density of #afc ,flue 7see ,flue gases74 ,path of in ,babcock ,wilcox boilers #eg ,waste 7see ,waste heat7 #bcb ,gaskets #cab ,gauges1 draft1 ,barrus #bed ,ellison #bee ,peabody #bee ,u-tube #bed ,gauges1 vacuum #aag ,grate ratio for anthracite #aia ,gravity of oils #bad ,grooving #ajb ,guerney's boiler #bd ,handhole fittings for ,babcock ,wilcox boilers #ej1 #ea ,handholes in ,babcock ,wilcox boilers #ej1 #ea ,hardness of boiler feed water #ajb ,permanent #ajb ,temporary #ajb ,testing for #aje ,hardness of fire brick #cjc ,heat and chemical methods of treating feed water #aje ,and its measurement #gi ,balance #bfb ,consumption of engines #ada ,latent #hd ,of liquid #abj ,sensible #hd ,specific 7see ,specific heat7 #hc ,total #hf ,transfer #cbc ,heat value of bagasse #bje ,by-product coke oven gas #bca ,coal #agg ,heat value of fuels1 determination of #agc ,determination of ,kent's approximate method #ahc ,high and low #agd ,heat value of natural gas #bbi ,oil #bae ,wood #bja ,heat waste 7see ,waste heat7 #bcb ,heaters1 feed water1 closed #aaa ,economizers #aaa ,open #aaa ,heating feed water1 saving by #aaj ,hero's engine #ac ,high and low heat value of fuels #agd ,high pressure steam1 advantages of use of #aai ,high temperature measurements1 accuracy of #hi ,horse power1 boiler #bfe ,evaporation 7actual7 corresponding to #bhh ,rated boiler #bfe ,stacks for various1 of boilers #bej ,hydrogen in flue gases #aef ,ice1 specific heat of #ii ,idalia1 tests with superheated steam on yacht #adc ,impurities in boiler feed water #ajj ,incomplete combustion of carbon1 loss due to #aeh ,injectors1 efficiency of #aab ,relative efficiency of1 and pumps #aab ,iron alum in feed water treatment #ajf ,kent1 ,wm41 determination of heat value from analysis #ahc ,stack table #bej ,kindling point #aej ,latent heat #hd1 #aae ,laying of fire brick #cje ,red brick #cje ,lignite1 analyses of #aha ,combustion of #aie ,lime and soda treatment of boiler feed #ajb ,used in chemical treatment of feed #aje ,lime treatment of boiler feed water #ajb ,liquid fuels and their combustion #bab ,loads1 economical boiler #bhc ,losses due to excess air #aeh ,due to unburned carbon #aeh ,due to unconsumed carbon in the ash #bfa ,losses in efficiency 7see ,heat balance74 ,in flue gases #aeh1 #aei ,low water in boilers #bih ,melting points of metals #ia ,mercurial pyrometers #hi ,moisture in coal1 determination of #agf ,in fuels1 losses due to #bei ,in steam1 determination of #abi ,mud drum of ,babcock ,wilcox boiler #ea ,napier's formula for flow of steam #cba ,natural gas1 burners for #bbi ,combustion of #bbi ,composition and heat value of #bbi ,nitrate of silver in testing feed water #aje ,nitrogen1 as indication of excess air #aeg ,in air #adg ,in flue gases #aeg ,nodules1 fire brick1 ratio of #cjc ,size of #cjc ,normal reading1 throttling calorimeter #aca ,nozzles1 steam sampling for calorimeter #acd ,location of #acd ,oil fuel1 burners 7see ,burners74 ,capacity with #bbd ,combustion of #bag ,comparison with coal #bad ,composition and heat value of #bac ,efficiency with #bbd ,furnaces for #bba ,gravity of #bad ,in combination with other fuels #bbd ,stacks for #bea ,tests with #bbd ,open hearth furnace1 ,babcock ,wilcox boiler set for utilizing waste heat from #bcf ,open heaters1 feed water #aaa ,operation of boilers #bia ,optical pyrometers #ia ,orsat apparatus #afj ,oxalate of soda in feed water treatment #ajf ,oxygen in air #adg ,flue gases #aee ,peabody draft gauge #bee ,formulae for coal calorimeter correction #ahh ,furnace for oil fuel #bba1 #bbb ,oil burner #bah ,peat #afg ,perkins' boiler #bd ,pfaundler's method of coal calorimeter radiation correction #ahg ,pipe coverings #cae ,data #cjh ,expansion of #cae ,pipe fittings #caa ,flanges #cji ,flow of steam through #cag ,radiation from bare and covered #cad ,sizes #cab ,supports for #cae ,piping1 boiler room #cjh ,pitting #ajb ,plant records1 coal #bic ,draft #bid ,temperature #bid ,water #bic ,plasticity of fire brick #cjb ,pressed fuels #aga ,priming in boilers #ajb ,methods of treating for #ajg ,properties of water #if ,proximate analyses of coal #agg ,proximate analysis #agc ,method of making #agf ,pulverized fuels #agj ,pump1 efficiency of feed #aab ,pyrometers1 expansion #hi ,mercurial #hi ,optical #ia ,radiation #ij ,thermo-electric #ij ,quality of steam #abi ,radiation correction for coal calorimeter #ahg1 #ahh ,correction for steam calorimeter #aca ,effect of superheated steam on #adj ,from pipes #cad ,losses in efficiency due to #cjg ,pyrometers #ij ,ratio of air supplied to that required for combustion #aeg ,reagents1 less usual in feed treatment #ajf ,records1 plant1 coal #bic ,draft #bid ,temperature #bid ,water #bic ,requirements of steam boilers #bg ,as indicated by evolution of ,babcock ,wilcox #de ,rumsey's boiler #bc ,safety of ,babcock ,wilcox boilers #ff ,salts responsible for scale #aja ,solubility of #aja ,sampling coal #bga ,nozzles for steam #acd ,nozzles for steam1 location of #acd ,steam #acd ,steam1 errors in #ace ,saturated air #adi ,saving by heating feed #aaj ,with superheat in ,idalia tests #adc ,with superheat in prime movers #adj1 #adb ,scale 7see ,thermometers7 #aja ,sea water1 composition of #ig ,sections1 ,babcock ,wilcox boiler #ej ,selection of boilers #bgg ,sensible heat #hd ,separating steam calorimeter #acb ,sizes of anthracite coal #aij ,bituminous coal #aia ,smoke1 methods of eliminating #aig ,smokelessness1 relative nature of #aig ,with hand-fired furnaces #aii ,with stoker-fired furnaces #aii ,soda1 lime and1 treatment of feed #ajc ,oxalate of1 in treatment of feed #ajf ,removal of scale aided by #cjj ,silicate of1 in treatment of feed #ajf ,treatment of boiler feed #ajc ,space occupied by ,babcock ,wilcox boilers #ff ,specific heat #hc ,specific heat of air #adh ,ice #ii ,saturated steam #ii ,specific heat of superheated steam #acg ,various solids1 liquids and gases #he ,water #ii ,spreading method of firing #aic ,stacks and draft 7see ,chimneys7 #bcg ,stacks for blast furnace gas #bbh ,oil fuel #bea ,wood #bjb1 #bed ,stayed surfaces1 absence of1 in ,babcock ,wilcox boilers #fi ,difficulties arising from use of #fg ,steam #aae ,as aid to combustion of anthracite #aia ,as aid to combustion of lignite #aie ,consumption of prime movers #bhi ,density of #aae ,flow of1 into atmosphere #cbj ,flow of1 into pressure above atmosphere #cah ,flow of1 through pipes #cag ,high pressure1 advantage of #aai ,history of generation and use of #ac ,making1 theory of #ib ,moisture in #abi ,properties of1 for vacuum #aai ,properties of saturated #abb ,properties of superheated #abe ,quality of #abi ,saturated #aae ,specific heat of saturated #ii ,specific heat of superheated #acg ,specific volume of #aae ,superheated #acg ,superheaters 7see ,superheated steam74 ,steaming1 quick1 with ,babcock ,wilcox boilers #gc ,stem ,correction1 thermometer #hj ,stevens1 ,john1 boiler #bc ,stevens1 ,john ,cox1 boiler #bc ,stokers1 automatic1 advantages of #aie ,babcock ,wilcox chain grate #aid ,overfeed #aif ,smokelessness with #aii ,traveling grate #aig ,underfeed #aif ,superheated steam #acg ,additional fuel for #aci ,effect on condensation #adj ,effect on radiation #adj ,fittings for use with #ade ,idalia tests with #adc ,specific heat of #acg ,variation in temperature of #ade ,with turbines #adb ,superheater1 ,babcock ,wilcox #acf ,effect of on boiler efficiency #aci ,supports1 ,babcock ,wilcox boiler #eb1 #ec ,tan bark #baj ,tar1 water gas #bbe ,temperature1 accuracy of high1 measurements #hi ,as indicated by color #ia ,of waste gases #bcb ,records #bid ,test conditions vs4 operating conditions #bgh ,testing1 boiler1 ,a4 ,s4 ,m4 ,e4 code for #bfg ,tests of ,babcock ,wilcox boilers with bagasse #baj ,coal #bhj ,oil #bbd ,theory of steam making #ib ,thermo-electric pyrometers #ij ,thermometer scale1 celsius #gi ,thermometer scale1 centigrade #gf ,fahrenheit #gi ,raumur #gi ,thermometer scales1 comparison of #hj ,conversion of #hj ,thermometer stem correction for #hj ,thermometers1 glass for #gi ,throttling calorimeter #abi ,total heat #hf1 #aae ,treatment of boiler feed water 7see ,feed water7 #ajb ,chemicals used in #aje ,less usual reagents in #ajf ,tube data #cji ,doors in ,babcock ,wilcox boilers #ec ,tubes in ,babcock ,wilcox boilers #ej ,ultimate analyses of coal #ahc ,analysis of fuels #agc ,unaccounted losses in efficiency #bfa ,unconsumed carbon in ash #bfa ,units1 boiler1 number of #bhi ,size of #bhi ,units1 ,british thermal #hc ,unreliability of ,,co#b readings alone #afb ,vacuum gauges #aag ,properties of steam for #aai ,valves used with superheated steam #cab ,variation in properties of saturated steam #aai ,superheat from boilers #ade ,volume of air #adg ,water #if ,volume1 specific1 of steam #aae ,waste heat1 auxiliary grates with boilers for #bce ,babcock ,wilcox boilers set for use with #bcf ,boiler design for #bcc ,curve of temperature1 heat absorption1 and heating surface #bce ,draft for #bcc ,fans for use with #bcc ,power obtainable from #bcb ,temperature of1 from various processes #bcb ,utilization of #bcb ,water1 air in boiler feed #ajf ,boiling points of #ig ,compressibility of #ig ,water feed1 impurities in #ajj ,methods of feeding to boiler #acb ,saving by heating #aaj ,treatment 7see ,feed water74 ,water-gas tar #bbe ,heat of the liquid #abj ,path of1 in ,babcock ,wilcox boilers #eg ,properties of #if ,records #bic ,specific heat of #ii ,volume of #if ,weight of #if1 #abj ,watt1 ,james #ag ,weathering of coal #afi ,webster furnace #ee ,weight of air #adg ,wilcox boiler #be ,wood1 combustion of dry #bjb ,wet #bjc ,composition and heat value of #bja ,furnace design for #bja ,moisture in #bja ,sawmill refuse #bjb ,woolf s boiler #bd ,zero1 absolute #ha ,,footnotes ,footnote #a3 ,see discussion by ,george ,h4 ,babcock1 of ,stirling's paper on ,water-tube and ,shell ,boilers1 in ,transactions1 ,american ,society of ,mechanical ,engineers1 ,volume ,,vi41 ,page #fja4 ,footnote #b3 ,when one temperature alone is given the true specific heat is given2 otherwise the value is the mean specific heat for the range of temperature given4 ,footnote #c3 ,for variation1 see ,table #ac4 ,footnote #d3 ,where range of temperature is given1 coefficient is mean over range4 ,footnote #e3 ,coefficient of cubical expansion4 ,footnote #f3 ,le ,chatelier's ,investigations4 ,footnote #g3 ,burgess-,le ,chatelier4 ,footnote #h3 ,for accuracy of high temperature measurements1 see ,table #g4 ,footnote #i3 ,messrs4 ,white ,taylor ,trans4 ,a4 ,s4 ,m4 ,e41 ,vol4 ,,xxi1 #aijj4 ,footnote #aj3 ,see ,scientific ,american ,supplement1 #fbd1 #fbe1 ,december1 #ahhg4 ,footnote #aa3 #dfj degrees below the zero of ,fahrenheit4 ,this is the nearest approximation in whole degrees to the latest determinations of the absolute zero of temperature ,footnote #ab3 ,marks and ,davis ,footnote #ac3 ,see page #abj4 ,footnote #ad3 ,see ,trans41 ,a4 ,s4 ,m4 ,e41 ,vol4 ,,xiv41 ,page #gi4 ,footnote #ae3 ,some waters1 not naturally acid1 become so at high temperatures1 as when chloride of magnesia decomposes with the formation of free hydrochloride acid2 such phenomena become more serious with an increase in pressure and temperature4 ,footnote #af3 ,l4 ,m4 ,booth ,company4 ,footnote #ag3 ,based on lime containing #ij per cent calcium oxide4 ,footnote #ah3 ,based on soda containing #eh per cent sodium oxide4 ,footnote #ai3 ,see ,stem ,correction1 page #hj4 ,footnote #bj3 ,see pages #abe to #abg4 ,footnote #ba3 ,the actual specific heat at a particular temperature and pressure is that corresponding to a change of one degree one way or the other and differs considerably from the average value for the particular temperature and pressure given in the table4 ,the mean values given in the table give correct results when employed to determine the factor of evaporation whereas the actual values at the particular temperatures and pressures would not4 ,footnote #bb3 ,see page #aag4 ,footnote #bc3 ,ratio by weight of ,o to ,n in air4 ,footnote #bd3 #d4cb pounds of air contains one pound of ,o4 ,footnote #be3 ,per pound of ,c in the ,,co4 ,footnote #bf3 ,ratio by volume of ,o to ,n in air4 ,footnote #bg3 ,available hydrogen4 ,footnote #bh3 ,see ,table #ca1 page #aea4 ,footnote #bi3 ,this formula is equivalent to 7#aj7 given in chapter on combustion4 #cd4ef theoretical air required for combustion of one pound of ,h 7see ,table #ca74 ,footnote #cj3 ,for degree of accuracy of this formula1 see ,transactions1 ,a4 ,s4 ,m4 ,e41 ,volume ,,xxi1 #aijj1 page #id4 ,footnote #ca3 ,for loss per pound of coal multiply by per cent of carbon in coal by ultimate analysis4 ,footnote #cb3 ,for loss per pound of coal multiply by per cent of carbon in coal by ultimate analysis4 ,footnote #cc3 ,the ,panther ,creek ,district forms a part of what is known as the ,southern ,field2 in the matter of hardness1 however1 these coals are more nearly akin to ,lehigh coals4 ,footnote #cd3 ,sometimes called ,western ,middle or ,northern ,schuylkill ,field4 ,footnote #ce3 ,geographically1 the ,shamokin ,district is part of the ,western ,middle ,mahanoy ,field1 but the coals found in this section resemble more closely those of the ,wyoming ,field4 ,footnote #cf3 ,see page #afa4 ,footnote #cg3 ,u4 ,s4 ,geological ,survey4 ,footnote #ch3 ,see ,steam ,boiler ,economy1 page #dg1 ,first ,edition4 ,footnote #ci3 ,to agree with ,pfaundler's formula the end ordinates should be given half values in determining ,t1 i4 e41 ,t 77,temp4 at ,b ,temp4 at ,c7 #b ,temp4 all other ordinates7 ,n ,footnote #dj3 ,b4 t4 u4 calculated4 ,footnote #da3 ,average of two samples4 ,footnote #db3 ,assuming bagasse temperature #hj degrees ,fahrenheit and exit gas temperature #ejj degrees ,fahrenheit4 ,footnote #dc3 ,dr4 ,henry ,c4 ,sherman4 ,columbia ,university4 ,footnote #dd3 ,includes ,n4 ,footnote #de3 ,includes silt4 ,footnote #df3 ,net efficiency gross efficiency less #b per cent for steam used in atomizing oil4 ,heat value of oil #ahejj ,b4 t4 u4 ,one ton of coal weighs #bjjj pounds4 ,one barrel of oil weighs #ccf pounds4 ,one gallon of oil weighs #h pounds4 ,footnote #dg3 ,average of #bj samples4 ,footnote #dh3 ,includes ,h and ,,ch#d4 ,footnote #di3 ,b4 t4 u4 approximate4 ,for method of calculation1 see page #age4 ,footnote #ej3 ,temperatures are average over one cycle of operation and may vary widely as to maximum and minimum4 ,footnote #ea3 ,dependant upon length of kiln4 ,footnote #eb3 ,results secured by this method will be approximately correct4 ,footnote #ec3 ,see ,chimneys for ,crude ,oil1 ,c4 ,r4 ,weymouth1 ,trans4 ,a4 ,s4 ,m4 ,e41 ,dec4 #aiab4 ,footnote #ed3 ,to determine the portion of the fuel which is actually burned1 the weight of ashes should be computed from the total weight of coal burned and the coal and ash analyses in order to allow for any ash that may be blown away with the flue gases4 ,in many cases the ash so computed is considerably higher than that found in the test4 ,footnote #ee3 ,as distinguished from the efficiency of boiler1 furnace and grate4 ,footnote #ef3 ,to obtain the efficiency of the boiler as an absorber of the heat contained in the hot gases1 this should be the heat generated per pound of combustible corrected so that any heat lost through incomplete combustion will not be charged to the boiler4 ,this1 however1 does not eliminate the furnace as the presence of excess air in the gases lowers the efficiency and the ability to run without excess air depends on the design and operation of the furnace4 ,the efficiency based on the total heat value per pound of combustible is1 however1 ordinarily taken as the efficiency of the boiler notwithstanding the fact that it necessarily involves the furnace4 ,footnote #eg3 ,see pages #bhj and #bha4 ,footnote #eh3 ,where the horse power of marine boilers is stated1 it generally refers to and is synonymous with the horse power developed by the engines which they serve4 ,footnote #ei3 ,in other countries1 boilers are ordinarily rated not in horse power but by specifying the quantity of water they are capable of evaporating from and at #bab degrees or under other conditions4 ,footnote #fj3 ,see equivalent evaporation from and at #bab degrees1 page #aaf4 ,footnote #fa3 ,the recommendations are those made in the preliminary report of the ,committee on ,power ,tests and at the time of going to press have not been finally accepted by the ,society as a whole4 ,footnote #fb3 ,this code relates primarily to tests made with coal4 ,footnote #fc3 ,the necessary apparatus and instruments are described elsewhere4 ,no definite rules can be given for location of instruments4 ,for suggestions on location1 see ,a4 ,s4 ,m4 ,e4 ,code of #aiab1 ,appendix #bd4 ,for calibration of instruments1 see ,code1 ,vol4 ,,xxxiv1 ,trans41 ,a4 ,s4 ,m4 ,e41 pages #afia-agjb and #agac-ad4 ,footnote #fd3 ,one to two inches for small anthracite coals4 ,footnote #fe3 ,do not blow down the water-glass column for at least one hour before these readings are taken4 ,an erroneous indication may otherwise be caused by a change of temperature and density of the water within the column and connecting pipe4 ,footnote #ff3 ,do not blow down the water-glass column for at least one hour before these readings are taken4 ,an erroneous indication may otherwise be caused by a change of temperature and density of the water within the column and connecting pipe4 ,footnote #fg3 ,for calculations relating to quality of steam1 see page #abi4 ,footnote #fh3 ,where the coal is very moist1 a portion of the moisture will cling to the walls of the jar1 and in such case the jar and fuel together should be dried out in determining the total moisture4 ,footnote #fi3 ,say ounce to #b ounces4 ,footnote #gj3 ,for methods of analysis1 see page #agf4 ,footnote #ga3 ,for suggestions relative to ,smoke ,observations1 see ,a4 ,s4 ,m4 ,e4 ,code of #aiab1 ,appendix #af and #ag4 ,footnote #gb3 ,the term as fired means actual condition including moisture1 corrected for estimated difference in weight of coal on the grate at beginning and end4 ,footnote #gc3 ,corrected for inequality of water level and steam pressure at beginning and end4 ,footnote #gd3 ,see ,transactions1 ,a4 ,s4 ,m4 ,e41 ,volume ,,xxxiii1 #aiab4 ,footnote #ge3 ,for methods of determining1 see ,technologic ,paper ,no4 #g1 ,bureau of ,standards1 page #dd4 ,footnote #gf3 ,often called extra heavy pipe4 ,footnote #gg3 ,see ,feed ,piping1 page #cab4 ,footnote #gh3 ,see ,superheat ,chapter1 page #ade4 ,footnote #gi3 ,see ,radiation from ,steam ,lines1 page #cad4 ,footnote #hj3 ,d1 the density1 is taken as the mean of the density at the initial and final pressures4 ,footnote #ha3 ,diameters up to #e inches1 inclusive1 are actual diameters of standard pipe1 see ,table #fb1 page #cjh4 ,footnote #hb3 ,diameters up to #d inches1 inclusive1 are actual internal diameters1 see ,table #fb1 page #cjh4 ,footnote #hc3 ,h4 ,p4 ,jordan1 ,proceedings of the ,institute of ,mechanical ,engineers1 #aiji4 ,footnote #hd3 ,zeitschrift des ,vereines ,deutscher ,ingenieur1 #aiji1 page #agej4 ,footnote #he3 ,heinrich ,grber--,zeit4 d4 ,ver4 ,ing41 ,march #aiab1 ,december #aiab4 ,leprince-,ringuet--,revue de ,mecanique4 ,july #aiaa4 ,john ,perry--,the ,steam ,engine4 ,t4 ,e4 ,stanton--,philosophical ,transactions1 #ahig4 ,dr4 ,j4 ,t4 ,nicholson--,proceedings ,institute of ,engineers ,shipbuilders in ,scotland1 #aiaj4 ,w4 ,e4 ,dally--,proceedings ,institute of ,mechanical ,engineers1 #aiji4 ,footnote #hf3 ,proceedings ,royal ,society1 ,vol4 ,,lxxi4 ,footnote #hg3 ,zeitschrift des ,vereines ,deutscher ,ingenieur1 #aiaj1 page #aaed4 ,footnote #hh3 ,proceedings ,institute of ,engineers and ,shipbuilders1 #aiaj4 ,footnote #hi3 ,natural or ,hyperbolic ,logarithm4