The Iron Age 1927-10-20: Vol 120 Iss 16

THE IRON AGE New York, October 20, 1927 ESTABLISHED 1855 VOL. 120, No. Hot Blast Applied the Cupola Carbon Monoxide Drawn from Point Below Charging Door Burned Combustion Chamber, Preheating the Blast VIAL VIAL, the author the article, vice-president and chief engineer the Grif- fin Wheel Co., Chicago. The hot blast cupola described was developed the Griffin Engineering Co., 410 North Michigan Avenue, Chicago, and covered United States letters patent No. 1,627,530, issued May 1927. The heating the blast said yield decided saving coke, power and labor, with increased control melting con- ditions, insuring greater uniformity the finished product. HERE has been fundamental change the remelting iron within shaft furnaces since the earliest invention pre-historic times. the 15th and 16th centuries considerable impetus was given cupola practice when the manufacture can- non was the principal feature the cast iron industry. Present cupola practice dates back the invention the steam engine the latter part the 18th cen- tury. The first application steam for industrial pur- poses was furnish power for blowing cupolas and blast furnaces and also pump water from coal mines, which were flooded account the inability make any headway hand pumping. This combination making available inexhaustible supply fuel for metallurgical purposes and for the generation steam started the factory system industry, which gave England her industrial supremacy for more than cen- tury. The cupola represents the most economical furnace for melting iron, shown the following table taken from Richards’ “Metallurgical Calculations”: Per Cent Thermal Steam boiler and hot blast stove........... Because its cheapness construction and rela- tively high thermal efficiency compared with the ex- pensive regenerative open-hearth process used the steel industry, the cupola has received very little at- tention from the standpoint economy fuel, for already stands the head the list this respect. Little Done Past Conserve Waste Heat from Cupola Through all the ages waste heat from the cupola has been observed, but account the economy the cupola compared with all other types furnaces, little has been done curtail the known waste. Attempts economy fuel consumption have been made sug- gesting very small very deep cupolas; tuyeres have been made every conceivable manner and shape, single rows and double rows with all kinds claims for economy, only find that they all operate about alike, with special difference economy fuel. Unsuccessful attempts have been made preheat the blast. Notwithstanding the failures prior attempts and contrary the principles laid down standard books cupola practice, the Griffin Wheel Co., Chicago, de- termined develop successful method preheating the blast. The experiments were conducted com- mercial basis cupola in. inside diameter, and after many delays and expensive alterations success- ful combination was made the old idea pre- heating the blast and the old idea charging the cupola with alternate layers coke and iron, pro- ducing new result, namely, the commercially suc- cessful preheating the blast, which factor, con- nection with successful demonstration several cupolas production basis, was sufficient obtain United States and foreign patents. Blast Preheated Burning Gas Drawn from Upper Wind Box The method applying the process shown Fig. which standard cupola used the or- dinary manner with upper wind box added below the charging door. Through this second wind box por- tion the gases combustion drawn from the cupola, passing combustion chamber where the inflammable carbon monoxide gas burned, developing increased amount heat which passes through the tubes preheater and through exhaust fan. The air for the cupola blast enters the preheater among the tubes which are heated with the cupola gas and passes the cupola through the ordinary wind box. Fig. shows cupola with blast heater suf- ficient size heat the air combustion for melt- ing capacity tons per hour. The hot blast pipe 1071 — - eiu shown leading from the blast heater the cupola. The blast pipe passing through the wall the left emergency connection, used case neces- sary operate the cupola with cold blast. Adjoining the heater flue which carries the gases combus- tion from the upper wind box the cupola the lower compartment the blast heater, shown section Fig. The small pipe leading from the hot blast pipe the flue by-pass supply heated air for the combustion the carbon monoxide gas from the cupola. The circulation the gases and the construc- tion the heater shown Fig. Fig. view the blast pipe leaving the blower and connecting with the heater. diaphragm placed the flanged joint the right which compels flow air travel through the pipe the left through the wall and into the blast heater. case becomes necessary operate the cupola with cold blast, the diaphragm removed from the flanged joint the right and placed into the flanged joint the left. other words, the cupola may changed from the hot blast cold blast and vice versa, pleasure. Fig. shows the exhaust fan platform the charging room. The gases combustion are drawn from the heater through the pipes shown. The two pipes leading downward connect with the upper part the blast heater, means which the gases are drawn uniformly from each end. The cupola shown the extreme left. Hot Blast Cupola Production Basis for Two Years The application the hot blast the Griffin cupolas has been successful operation regular produc- tion basis for period two years, melting approxi- mately 200,000 tons iron. The results obtained from hot blast cupola in. inside diameter melting 125 tons per day and from ordinary cupola operating the plant under the same conditions are shown in the # In tne fot owing compar ison: COMPARISON ORDINARY CUPOL PRACTICE WITH GRIFFIN HOT BLAST CUPOLA PRACTICE Cold Hot Blast Blast Lb. ec rular charge per ton elted 995, 16 Total Ib >| per ton melted G9 19 Bed harge oke D., inus ¢ I i charg 5,500 1.700 Coke, regular charge, 1,12 1,000 Tron charges, in lb 10,000 12.500 Temperature deg. Fahr., escaping from cupola the lining, average 580 At center of cupola 562 310 Comparison of Gas Analyses from Cold Blast and Hot Blast Cupolas the Same Diameter and Melting the Same Rate per Hour, Using the Respec tive Amounts of Coke Shown Above ——Cold Blast Cupola —— Hot Blast Cupola —— Of oOo, % % % 9.8 1.4 16.6 72.2 12.6 0.4 12.4 74.6 10.2 0.4 16.8 72.6 9:45a.m. 15.0 0.6 9.4 75.0 10.0 0.4 15.6 74.0 12.0 0.8 10.4 76.8 10:50a.m. 19.4 0.2 17.0 72.4 10:45 a.m. 15.0 0.4 9.8 74.8 11:15a.m. 10.8 0.2 15.4 73.6 14.2 0.4 10.2 75.2 11:45a.m. 10.8 0.2 16.0 73.0 1:10p.m. 15.6 0.6 8.4 75.4 1:00 p.m. 12.6 0.2 13.0 74.2 —_ - 12.0 0.2 14.0 73.4 Average 14.1 0.5 10.1 75.3 Average 10.8 0.4 15.6 73.2 The above results indicate clearly that combustion the hot blast cupola more complete than the cold blast. The averages indicate that about per cent carbon dioxide formed for the cold blast and per cent for the hot blast. the more complete combustion the hot blast that large factor fuel economy. approaching the subject stopping some the waste fuel consumption, essential that the Weight Weight Gravity Cu. Air Ox n 1. 0.0887 0.0186 Nitrogen .... 0.0781 0.0610 Argon and carbon dioxide 1.470 0.1186 0.0011 Carbon dioxide 1.530 0.1222 Carbon monoxide 0.967 0.0778 1072—October 20, 1927, The Age amount waste heat and the form which exists should known. There are certain heat losses which cannot avoided, such the heat required for the formation slag, for the disintegration limestone, for the dissociation moisture and for radiation, which includes the heat taken the cupola lining, all which constitutes fairly constant amount, which does not give promise any great possibility sav- ing. The three important and obvious forms heat loss which are recoverable are the sensible heat the gases they leave the cupola, the loss from in- complete combustion and the potential heat the com- bustible gases they emerge from the charges the charging door. important that the amount these losses should fairly well understood before any scheme for their partial elimination can considered. With this mind, necessary prepare heat balance, not for any absolute theoretical consideration the various elements the analysis, but merely practical working basis for foundry practice. The constants used are shown bottom page. Those relationships make possible calculate all the quantities which enter into the various stages combustion definite amount carbon, for all the carbon the fuel must accounted for the gases combustion, either carbon dioxide car- bon monoxide. Comparison Temperatures Developed Two Ex- tremes Combustion Carbon dioxide non-combustible gas represent- ing perfect combustion and develops maximum amount heat, also maximum flame temperature for direct combustion carbon. The amount heat repre- sented 14,560 B.t.u. for each pound carbon burned, and the temperature developed approximately 3700 deg. Fahr. Carbon monoxide represents the first state com- bustion, developing minimum amount heat and minimum temperature, and highly combustible gas. The amount heat developed this reaction 4360 B.t.u. for each pound carbon consumed, developing flame temperature 2340 deg. Fahr. each case assumed that the theoretical amount air has been used; any excess air will reduce the flame temperature proportion the excess air heated. When the combustible carbon monoxide burned carbon dioxide, the amount heat developed each pound carbon 10,200 B.t.u., developing flame temperature 3800 deg. Fahr. The quantity air required and the composition the resultant gases volume and weight for the two extremes combustion are shown the following table: For Lb. Carbon Plus Per Cent Excess Air for tion Silicon, Manganese, Slag, Carbon Monoxide to Carbon Carbon Carbon Dioxide Monoxide Dioxide Requirements: 31.6 15.8 15.8 Results: Carbon dioxide, 3.66 3.66 Carbon monoxide, ..... 2.33 ati. re 9.35 4.67 9.35 Carbon dioxide, cu. ft. 30.00 30.00 Carbon monoxide, cu. ft. ... 30.00 Nitrogen, cu. ft. ..... ace ie 119.0 59.50 119.00 Per cent of carbon dioxide 20.0 -0.0 Per cent of carbon monoxide 35.5 : Temperatures, deg. Fahr 3,700 2,340 3,800 B.t.u 14,560 4,360 10,200 Per Cent Per Cent of Air by of Air by Weig Volume Weights 75.59 78.11 Nitrogen Manganese 1.36 0.92 Oxygen Calcium re B The foregoing discussion relative the formation carbon dioxide and carbon monoxide gases shows the combustion that takes place for the two extreme limits combustion. When combustion perfect the maximum amount heat produced, which case carbon diox- ide forms per cent the gases combustion with carbon monoxide. the opposite extreme, which produces the minimum amount heat, carbon mon- oxide forms 33.5 per cent the gases combustion, with carbon dioxide. Conditions within the cupola will always somewhere between these extremes. The analysis the gases they emerge from the cupola reveals great variety information. shows the amount heat that being developed from the fuel, the temperature the combustion zone, the amount oxygen that being used oxidize the ele- ments such silicon, manganese, iron, etc., and, reference heat balance table, shows the number pounds iron that are being melted for each pound fi Stack Ga 4 Exhaust Fan y iJ Charging 500° | | OV UU UU | UUU UCL ul } & 7] Winc Box j <0 r | Ore f ] 600 F \ 7500°F = i iV > | | 3/00 °F 5att/e ‘an | re “Bed Coke: —— — — — — — — — ° c = 7 1 4STrIDVI | | 4474) BLAST HEATER coke. closely followed, the gas analysis will indi- cate the best rate flow air through the com- bustion zone produce the greatest amount heat, but because the gases are invisible, their relationship seldom sought through gas analysis, which the simplest all chemical determinations. From Table the following observations are made: One per cent increase carbon dioxide the gases com- bustion necessitates decrease 1.67 per cent carbon monoxide hence the amount heat developed from the combustion Ib. carbon, when the gas analysis known, is easily calculated from the following relation- ship: One per cent carbon dioxide develops 728 B.t.u. (ne per cent carbon monoxide develops 130 per cent increase carbon dioxide represents in- crease 510 B.t.u. per cent carbon dioxide accompanied approxi- mately per cent nitrogen. per cent carbon monoxide accompanied approxi- mately per cent nitrogen. per cent carbon dioxide represents flame temper- ature 185 deg. Fahr. per cent carbon monoxide represents flame temper- ature deg. Fahr. \n increase of 1 per cent of carbon dioxide therefore indi- cates net increase deg. flame These figures are the theoretical results from burn- ing pure carbon the cupola. The temperatures are never reached cupola account slight excess Lower Wind Box air and imperfect means bringing each atom oxygen contact with each atom carbon. The tem- peratures will drop proportion the impurities the coke compared with pure carbon. The reports cupola gas analysis writers cupola practice are very meager, notwithstanding the fact that gas analysis fundamental correct understanding the quality the product well fuel economy. Heat Lost Cold Blast Cupola Because Large Amount Carbon Monoxide Produced The wide variation results different times the same cupola and different cupolas depends pri- marily upon the uniformity with which the fuel placed the cupola and the rate which the air introduced into the combustion zone. The number charges the cupola and the heat gradient the gases while preheating the charges may have decided Gases Combustion the Cupola Drawn from the Upper Wind Box the Com- bustion Chamber the Blast Heater. Here the carbon mon- oxide the gases burned, developing heat which passes through tubes the blast heater exhaust fan. The air for the cupola blast heated contact with the blast heater tubes and enters the cupola through the ordi- nary wind effect the ultimate combustion reducing the car- bon dioxide originally formed into carbon monoxide the gases combustion pass through layers incan- descent coke, thereby absorbing 10,200 B.t.u. for each pound carbon represented the reduction. ordinary cupole practice there excess coke the first charge, resulting low stage combustion for the first few minutes after the cupola blast ir. which only per cent per cent carbon dioxide formed and per cent carbon monoxide. the excess coke burned away the percentage carbon dioxide gradually rises until per cent carbon monoxide. This refers the larger cupola from tons per hour and con- tinuing blast for hr. per day. necessary have excess carbon monoxide the gases combustion prevent oxidation the metal, which the most active agent lowering the quality the product. paper delivered before the American Foundry- men’s Association Cameron 1904 the per- centage carbon dioxide the gas from 44-in. cupola given per cent, and from 66-in. cupola, 10% 12% per cent. Bradley Stoughton his work the “Metallurgy The Iron Age, October 20, 1927—1073 | H | 2 OE Iron and Steel” gives the following average analysis for several different cases: Average Percentage of Carbon No of Carbon > hr. 10 min.. l 10.3 11.7 hr. 40 min. to 4 hr. 43 l hr. 53 min. to 4 hr min H 8.1 18.0 \nother cupola 1 hr. 30 min From the above discussion and from long experience melting large tonnage iron numerous cupolas may considered established that the character combustion ordinary cupola practice represented per cent carbon dioxide and 18.4 15.1 per 2 cent carbon monoxide. This range analyses fur- nishes the data for starting point calculating the heat balance for cold blast cupola practice. There are other sources heat than those arising from the com- bustion carbon, such the oxidation silicon, man- ganese, sulphur, iron, etc., which require oxygen for the chemical reaction which represented excess air above the requirements for the combustion coke. This accounts for the excess nitrogen present the gases combustion. The heat from these sources not taken into consideration when discussing heat bal- ances. Economy from Use Hot Blast Cupolas Due More Perfect Combustion assume that the air combustion delivered the combustion zone 600 deg. Fahr., there are two additional factors which enter into consideration the heat balance: definite amount sensible heat carried the combustion zone which added the quantity heat de- veloped combustion. addition the sensible heat carried the com- bustion zone, the combustion is intensified, resulting in a larger percentage carbon dioxide and smaller incomplete combustion represented carbon monoxide. The economy the use the hot blast arises largely from the more perfect combustion. The temperature the gases after passing two charges iron will reduced about 1500 deg. Fahr. 1074—October 20, 1927, The Iron Age the Griffin hot blast cupola approximately per cent the gases combustion are withdrawn from the cupola below the charging door, leaving per cent pass through the remaining charges, and ac- count the smaller volume the velocity checked, giving greater time for the transfer heat from the gases combustion the charges coke and iron through which they pass. For that reason the temper- ature the per cent gases which emerges from the cupola the ordinary manner reduced 600 deg. fact, not all difficult make the con- ditions such that the temperatures are reduced 200 300 deg. Unavoidable Heat Losses Cupola Operation consider the heat losses within the cupola which arise from radiation, formation slag, liberating carbon dioxide from limestone, dissociating moisture the blast and the coke, the sensible heat contained the Blast Heater Shown Suf- ficient Heat the Blast for Capacity Tons per Hour. The blast pipe shown con- necting the blast heater with the cupola The pipe through the wall emergency passage, used case necessary operate the cu- pola with cold blast gases they leave the cupola, incomplete combustion, etc. Radiation Radiation represents the heat absorbed the brick lining and the heat which passes through the shell the cupola, amounting from per cent per cent the heat generated the combustion carbon. Slag The amount slag for each pound carbon will vary slightly according the number pounds iron melted for each pound coke consumed. may assumed ordinary practice that about one-third pound slag formed for each pound coke consumed. One pound slag requires approximately 900 B.t.u. for its formation. Liberating Carbon Dioxide assumed that the amount limestone re- quired for each pound coke will contain from 2/5 dioxide from limestone requires about 840 this basis the approximate amount heat required for breaking limestone and liberating the carbon dioxide can and placed among the losses the heat balance. Moisture The heat loss account moisture the blast uncertain quantity and varies through wide range. hot days with high humidity the loss impor- The Leaving the Blower ranged that Removing Diaphragm from the Flanged Joint the Right and Placing the Flanged Joint the Left the Cupola May Operated Cold Blast Instead Hot Blast tant factor cupola operation, whereas the winter months, with low humidity, this factor negligible. The total these four items amounts from 1600 2200 for each pound coke consumed. Wuste Gases The loss represented the sensible heat the gases they emerge the charging door depends upon their temperature, which varies over wide range different cupolas and different locations the same cupola. The gases are invariably higher tem- perature next the lining than the center the charge. The difference usually per cent more the temperature the center. case the tem- perature the lining 1200 deg. Fahr., may expect the temperature the center the charge 900 deg., whereas the temperature the lining 900 deg., the temperature the center will 600 deg., and the temperature the lining low 600 deg., the temperature the center will about 400 deg. For the purpose our analyses heat losses, Ona Platform (to the Left) the Charging Room Fan which Draws the Gases Combustion from the Blast Heater through the Pipes Shown. The cu- the extreme left have taken the temperature 800 deg. above the atmospheric temperature representing ordinary practice cold blast cupolas. the hot blast cupola the temperature the escaping gases much less. For the purpose preparing heat balance have assumed the temperature 600 deg. Also the case the hot blast cupola necessary consider the sensible heat withdrawn below the charging door, the temperature the escaping gases from the exhaust fan and the amount sensible heat which enters the cupola with the air for combustion. Heat Available for Melting After Making Deductions After making these deductions from the heat gener- ated have the remainder available for melting iron, and for easy calculation have used 500 B.t.u. the heat necessary raise the temperature iron from the cold stock the melting point, supplying the latent heat fusion, and raise the temperature the molten iron 2600 2700 deg. Fahr. assumed that the carbon content the coke The Iron Age, October 20, 1927—1075 > “ a A — — — — Heat Balances Cold Blast and Hot Blast Cupolas Cold Blast, Griffin Hot Blast, Stages Combustion Stages Combustion Cu. 95.0 98.2 101.5 104.8 108.1 111.3 7.6 7.9 8.2 8.7 8.9 busti I CO by volu 18.4 16.8 15.1 13.4 11.8 10.1 vol 72.6 73.2 73.9 74.6 75.2 75.9 l 100.0 100.0 100.0 100.0 100.0 100.0 ( t gase 101.2 103.8 106.4 109.0 111.5 114.2 } total ec 8.4 8.7 2 9.5 9.7 ipola S00 600 600 600 tion ne 9540 2 600 2 660 2.920 2,980 %,120 B.t j } t 600 deg 1,263 1,302 1,341 heat 7,398 7.819 8,241 9,925 10,386 10,846 Heat Losses leavi (B.t.u.) 1,684 1,73¢ 1,789 830 Gases to r u rato 1500 deg Available for melting (B.t.u.) 3,923 1,204 4.485 5.656 5,966 Lb. iron melted (500 B.t.u. per lb.) 7.8 8.41 8.97 11.31 11.93 2.5 Lb. coke per ton melted..... 255 237 223 177 168 159 Total coke per ton iron melted 272 258 212 203 194 Cu. ft. air per Ib. melted.... 12.1 11.8 11.3 9.2 9.1 per ton melted.. 200 93.500 22,700 18,200 ton Ited 1.944 1.880 1,816 1,472 1,456 1,424 ble Losses Sens gas (B.t.u.) 1,684 1,789 830 877 tial heat (B.t.u.) 3,793 2,950 2,484 I (B.t.u.) 5.951 >. 582 4.202 83.804 3.361 I waste heat cor ired heat used for melting 161.2 124.5 75.0 64.0 54.0 Tic (per t) 21.0 33.2 35.4 44.5 47.0 49.5 per cent and that the difference between theo- the following saving pounds coke per ton melted: onside ration and practical performance Pounds Coke Required Melt Ton Iron Under cent; other words, have assumed per cent Various Conditions Combustion efficiency combustion. Applying these figures Cold blast. COs, 255 Ib. 10% 237 Ib. 11% 223 heat balance and tabulating them for the various stages Hot 12% 177 Ib. 168 Ib. 14% 159 Ib. combustion within the range cupola practice, each stage being represented variation per cent carbon dioxide gas the gases combustion they emerge the charging door, places the infor- mation form that mere inspection shows the amount iron melted any given condition combustion. The accompanying table heat balances indicates SEPTEMBER SHEET SALES Nearly Per Cent Ahead August and Ex- ceeded Shipments September sales independent sheet steel manu- facturers made even better showing the final report than was indicated the preliminary estimate issued Oct. Actual were 258,427 tons, 8427 excess the preliminary figures, and compare with 177,647 tons August. sales Sales exceeded shipments for each pound coke for Saving of coke | per ton melted 78 Ib. 69 Ib. These savings are entirely within the possibilities the hot blast operation. The percentage saving will depend largely upon the character the material melted, the quality coke used, the character the finished product and the degree perfection attained the present cupola. made during the period governmental control production and distribution the war period. The new code represents study covering production over the past years and recognizes the shifting from steam electrically driven mills, other mill better- ments and the increased efficiency man power. Its adoption means that, comparison with former months, the percentages the September report aver- age approximately per cent lower than the old basis reckoning. The figures for September with comparisons follow: practically 28,000 tons, and unfilled orders the 1927 end the month were 37,455 tons more than the *Sept. end August. Production ran almost 10,000 tons less Total No. mills.... 719 719 719 710 than shipments, but included the shipments for the tons. reporting 2.6 2.6 2.6 month were more than 12,000 tons stock that was Sales 177,647 448,147 end August. The total that item Aug. was Unfilled orders, tons..... 350,117 312,662 353,413 731,977 114,762 tons; at the end of September it was 102.554 ord rs, tons nsold stocks, tons...... 34,5 tons. With the September report the National Asso- ciation Sheet and Tin Plate Manufacturers, new 62.6 80.3 80.2 96.2 Unfilled orders ... 99.3 94.2 9.6 Hitherto, the premise has been 7.65 net tons per turn 34.6 sheet mills and 22.635 net tons per turn jobbing Unsold stocks........... 15.1 16.4 15.1 10.8 mills, based upon turns per week and weeks per *Basis for calculation capacity tonnages: Sheet mills, year. The new basis puts the average production 8.67 net tons per turn; jobbing mills, 22.56 net tons per sheet mills per turn 8.67 tons and jobbing mills 22.56 tons. The old basis found its origin study 20, The Iron Age mills 7.65 net tons per turn; jobbing mills 22.635 net tons per turn. Fuels—Past, Present and Prospective Changes Traced Over Century—Smoke Production One Backward Step—Gaseous Fuels Favored ISCOVERY coal this continent credited Father Hennepin, near the Illinois River LaSalle County, The record com- mercial shipments from Jackson County, barge New Orleans shows such activity have been inaugurated 1810. That event, far the records go, does not seem have been preceded any earlier activities from the coal fields the east- ern States. One the earliest accounts, giving glimpse the fuel situation 100 years ago, article Mar- cus Bull, published brochure 1826 the Amer- ican Philosophical Society, Philadelphia. com- piled estimate the quantity and type fuels used Philadelphia per year, and the values ob- tained were doubtless representative for the United States. Out the total consumption fuel, per cent was estimated wood, per cent was char- coal and little over per cent was anthracite. populous center like Philadelphia the smoke-produc- ing bituminous fuel was less than per cent. Use fuel was confined almost entirely supply- ing household needs for cooking and heating. The use anthracite was just beginning advocated substitute for wood the household. Only years before, Fulton had made his trip the Hudson. was still years before trans-oceanic voyage was made steam. The first locomotive America had not yet been fired up; when was, three years later, the fuel was wood. Changes within the Century Estimates Marcus Bull 1826, 11,000,000 tons fuel year for the entire United States, repre- sent about one ton per capita. estimate the coal output for 1821, from other sources informa- tion was 1322 tons, all anthracite. From this status have advanced 600,000,000 tons, about tons per capita. About one-sixth this tonnage anthra- cite and the remainder bituminous coal. The esti- mated value the mines $1% billions, and the consumer, with shipping charges added, the annual cost would exceed billions. Types fuel have changed that, instead non-smoke-producing fuels various sorts aggregat- ing per cent the total, 1826, the smokeless type has practically disappeared. are now con- suming various fuels over per cent which are smoke making. Advance efficiencies has been commensurate with the enormous expansion volume. This feature credited the engineer, whose strides can readily noted more scientific boiler settings, improved stokers, turbine engines, pulverized coal, superheaters, economizers, and high boiler pressures. One might think that the engineer had about reached his limit, but more likely has just made good beginning. Pall Smoke Not All Industrial additional characteristic which has left its mark more ways than one the smoke evil. This has seemed inevitable result the increase the use bituminous coal. And why should there smoke? The ignition temperature marsh gas between 1200 and 1300 deg. Fahr., bright cherry red. ene requires above 600 deg. Fahr. for ignition. These *Professor applied chemistry, University Urbana. This abstract the opening address first “national fuels sponsored the American Society Mechanical Engineers and held St. Louis, 13. PARR* are some the more products evolved from bituminous coal when heated. If, burning coal, they are disengaged with insufficient oxygen supply complete their combustion, while burning they strike sufficiently cooler surface lower their temperature below the ignition point, their function mainly altered from heat producers smoke producers. the steam generating plant these factors controlled effective manner slow and evenly distributed additions coal, special setting the boiler—hence the modern mechanical stoker and the elevated elongated boiler settings provide both space and time for the combustion gases fore cold surfaces are encountered. the case with the average household apart- ment heating unit entirely different. Here the high temperatures not prevail. Mechanical stokers and spacious combustion spaces are absent. Moreover, the man the house the janitor has other duties perform. fills the combustion chamber the limit and sets the dampers for prolonged period automatic control. During the major part this period the so-called “heater” simply device for stewing off tars and vapors inconceivable variety compositon, odor and filth, for the effective work polluting the atmosphere. Some the hopeful features the case are the following: i—VPublic intelligence is growing. This fuel conference sufficient confirmation that fact. 2—Scientific and investigational intelligence has mad: wonderful advance in this line in recent years; one might almost say, recent months This conference will prove excellent medium for bringing valuable data forward and will promote further study and specific application research being promoted both and private agencies today as never before. This confer ence should serve clearing house for results obtained with a view to their scrutiny and discussion and sifting from the standpoint practicability and the general welfare t—QOur knowledge of the constitution of coal has de- veloped marked pace the last few years. of the underlying principles of coal carbonization have kept abreast the fundamental data thus developed relating the constitution this complex material, Theoretical have been established regarding the possibility processing bituminous coal under such conditions will result in (1) a solid smokeless fuel admirably suited to domestic use, (2) a gas of high quality and in sufficient volume to make it attractive to the gas maker, and (3) tar of considerable volume and established rating in the current markets using such material The ideal fuel heating medium gas. Its smokeless combustion, high efficiency, cleanliness and convenience give status unapproached any other type fuel. When reaches the stage volume- production extent where costs can materially reduced, the extension its use will greater than can remotely realized now. shall welcome and encourage every agency and process calculated promote that end. The low even the high-temperature carbonization coal, com- plete gasification, improvements the water-gas re- action, the increased demand from industrial heating. and other developments such the Brunler engine other applications underwater combustion for power evaporative purpose—these, and many other possibilties now emerging, furnish most encourag ing outlook whose reduction every-day industrial and living conditions shall certainly see consum- mated the next few years. The Iron Age, October 20, 1927—1077 — : 3 rig | tunnel from Canal Street, New York, Jersey City, includes two parallel tubes cast iron, ft. apart, dipping 100 ft. be- river level. iron shell con- sists rings 29% ft. diameter and in. composed, shields, ft. diameter and ft. long, started from opposite sides the river. right shows the faces two shields the day before junction was made pressed forward means 200-ton jacks reacting against the completed portion the tunnel lining. flanges the segments were connected special 1%-in. steel bolts put under 25,000 Ib. per sq. in. initial tension 4-ft. wrenches. Joints were made with red lead grom- mets and lead wire caulking with pneumatic tools. Hudson River cast iron tubes form larye part the 9250-ft. connection between Canal Y., and Jersey City, formal opened traffic next month. tunneling was started frem four shaft two sunk each side the Huds River, each shaft ft. plan ft. high, made with double steel walls about ft. apart. ing pictures help tell the part the story enterprise called for the expenditure $48,000,000. The accompany- sae WITIAT Le : under the center the river. Each was may seen the lower and upper parts the erec- tor which the segments were swung into place. AY = + ~ the concrete lining work, steel forms mounted adjustable steel travel- crs were started the center the tunnel worked both ways, building 60-ft. lengths the lining. tube has 20-ft. granite paved road- way for two lines one-way traffic, ac- commodating 1900 vehicles per hour. From the space under the roadway, fresh air, deliv- rate 3,761,000 cu. ft. per min., ssues through frequent openings the road- vay level and escapes through numerous open- ngs the tunnel ceiling. The estimated cost operating the ventilating system, designed prevent longitudinal air currents, $350,- 000 per annum. bd J | y a > 4 = How Dry Blast Furnace Gas Silica Gel Tried England—Gayley Process Compared —High Frequency Induction Melting and Boiler Steel Brittleness Reviewed British Steel Men (Special Correspondence the Iron and Steel Institute Glasgow, Sept. 22, opened with announce- the secretary that Carnegie gold medals were awarded the following: proceedings the second day the fall meet- nent J H. Whiteley for his research on “The Eggertz for Con:bined Carbon Frank Bainbridge for his research “The Effect of Fluorspar Conditiors on the Phosphates in Basic Slag. Sands and Their Behavior under High Temperatures.” The papers, which were read that day and some other days, are abstracted follows: Use Silica Gel for Drying Blast NDER the above title, Edwin Lewis described the plant erected the Wishaw Works the Glas- gow Iron Steel Co., Ltd., treat 35,000 cu. ft. air per min. through the medium silica gel. The main features, from the blast furnace point view, are that atmospheric temperature can absorb least per cent its weight water from the air with efficiency 100 per cent, and that raising the temperature this water can driven off, leaving the re- activated gel ready for another cycle Since this plant the Wishaw Works produced the largest amount iron recorded their history and the fuel consumption was the low- est for many years; not less than per cent the increased output was apparently due drier blast, and substantial return has already been shown the cap- ital cost. the question the best degree dryness the blast, generally agreed that improved furnace operation follows with increased dehydration down grain per cu. ft. the other hand, certain reactions the furnace are slowed down when the gas below “calcium dryness, which represents about 0.1 grain per cu. ft. What happens between not known. Silica gel offers opportunity exploring the unknown field between 0.1 and 1.0 grain per cu. ft., and hoped Wishaw later date venture into this region. William Simons said that the first practical applica- tion extracting moisture was 1904, when Mr. Gay- ley read his paper before the institute. that time great number people followed Mr. Gayley’s sugges- tions. Half dozen plants were put the United States; one was put Cardiff, and thought one was erected Germany. The cost the Gayley process was very great, and very little compensation was ob- tained for it. the previous Monday saw the silica gel process Wishaw, and was much impressed with its simplicity. The only moving parts were the fan and the motor working it, contrasted with the Gayley system which there was 300 hp. engine working the ammonia com- pressor, the brine pumps and the condenser would therefore seen once that the silica gel striking departure which will reduce very materially the cost extracting the moisture. did not know whether the author not quite right observing that the money might have been bet- ter spent improving other conditions. any rate very important, said, get the highest efficiency other papers presented before the Tron and Steel Institute appeared THe Oct. and 20, The lron Age the stoves, reduce the amount gas that used the stoves, and get much surplus gas available possible order reduce fuel consumption the works, particularly when found, the case his works, that the use dry air the value the gas reduced doing. The author had shown that, per cent obtained. That had not been the experi- ence his works, but the blast furnace manager the opinion that the furnace worked better and that there was economy coke consumption. Blast Furnace Gas Producer Benjamin Talbot, the president elect, thought Mr. Simons had referred the key the position when modern steel plant, that necessary consider ex- actly the composition the gas obtained from the blast furnace. larger volume obtained for use the other departments believes greater economy will forthcoming. other words the blast furnace more effective gas producer than separate gas pro- ducing plant, when can produced surplus. Gayley Process Costly means drying air, David Roberts thought the one under consideration deserved very careful study. impossible tell until has been practical use for some years whether all the results that the author has given will borne out actual practice. one those who listened Mr. Gayley describe his process New York 1904, and seemed him then that had tremendous future before it. But unfor- tunately, partly due the excessive cost running the plant and for other reasons, had the success first anticipated. fact when was America year two later was told that the Gay- ley process fell short actual practice. Whether the same experience would attained with silica gel, did not know. was certainly exceedingly simple arrangement Use the Gas Important Personally had always felt that dry air right. had looked into blast furnace using dry air and found that the combustion seemed better, while the operators told him that the operations were more regular. the other hand thought the feature blast furnace working this country which needed the greatest amount attention was the use made the gas obtained from the furnace. modern equipments kept the highest pitch efficiency, the works Germany, America and other places, was noticeable how much trouble was taken utilize everything the greatest possible advantage. James Henderson did not agree with some the authorities that the blast furnace ought treated gas producer. the contrary, thought every effort should made cut down the amount fuel consumed, even the risk reducing the number B.t.u.’s the quality the gas that was obtained. Silica Gel Another Role Prof. Desch thought the author’s very im- portant paper contained the first definite proof the real value dry blast supported was care- fully arranged set figures. The process drying using some adsorbing material for the moisture, which had been tried many places, depended entirely the perfect reversibility the drying agent. un- derstood the experiments made Germany with cal- cium chloride failed because the process could never made perfectly reversible. very slight overheating the calcium chloride during reactivation spoiled it. The most remarkable feature the material silica gel that seems perfectly reversible. described the behavior silica gel experi- ments different from those the author’s. One speci- men silica gel use for three years had been used over and over again for adsorbing all kinds vapors. the original specimen was put through the first experiment which had been subjected three years ago, and the curves adsorption obtained the vapor were exactly the same. Apparently its re- peated use with variety material had not affected the structure the silica gel. That statement, said, could not made any other drying agent. Blast Furnace Not Gas Producer Lewis, reply, referred the ease opera tion mentioned Mr. Simons. 20-hp. motor was required for pushing the activating gas through and some hand-operated valves. When the experimental stage was finished, thought the whole plant could looked after one moderately responsible man shift, fairly well-trained furnace man. Three Ways Economize Fuel With regard Mr. Talbot’s remarks the use gas steel works, desired economize fuel the blast furnace, there are three ways, and three ways only, which can done. the first place would reduce the quality the top gases; the sec- ond place would reduce the quantity the top gases; and the third place would reduce sensibly the heat the top gases. The user the gas for other pur- poses must carefully weigh the possibilities and see whether was better run the furnaces gas pro ducers have separate gas producer plant. One point which had not been mentioned, added, was that desired run the blast furnace gas producer, far better run efficient gas producer, and that would attained keeping con- stant blast. thought was possible that several the Gay- ley plants which were stopped were stopped for the rea- son that was found far better spend the money other directions and not worry about the maintenance costs keeping the Gayley plant running. Constant Moisture Means Better Iron regard Mr. Talbot’s remarks, suggested that, blast furnace were being run gas pro- ducer with constant moisture the blast, one would obtain, addition better general running, much improved quality iron. regarded important pin down one the many variables. One the va- riables was the size ore. During one the last three weeks, owing sudden change the nature the ore used, the output his plant dropped per cent, due that one variable only. High Frequency Induction Melting PAPER the use high-frequency electricity for melting metals was contributed Campbell. method which now available for the industrial production steel, and applicable the melting tool steel and the manufacture small steel castings. With high frequency rotary generators now available reasonable cost the furnace installation simple, consists only the motor-generator, bank con densers improve the power factor the furnace cir- cuit any required degree, and tilting furnace simple but unusual design. addition, suitable con- trol instruments, regulator and switches complete the electrical plant. record showing typical day’s work with small unit only 100 kva., pouring cwt. high-grade nickel-iron alloys from siliceous crucible entirely free from carbon, gave the following result: heats, charge 3024 hr. total melting time; hr. min., total time melting and pouring. The cost about equal that small Héroult are furnaces, and the steel made under crucible condi- tions, with the advantage absolute homogeneity and intensity mixing and melting temperature which only limited the refractories and the melter erating the furnace. The president, Mr. Harbord, inviting discussion, said had inspected one the author’s furnaces about fortnight ago, and was most interesting sight see the molten steel pouring out furnace contained wooden box. The temperature outside the furnace was low that there was not the slightest risk the wood becoming ignited, but nevertheless molten steel was pouring out from the interior. was crucible furnace which the heat was developed the center the mass. Dr. Desch said that was strong believer the principle high frequency heating. had seen the high frequency induction furnace working very successfully America with nickel alloys, and owned deal experience with the earlier type high frequency induction furnace, the Ajax-Northrup fur- nace. possible, said, melt material very high melting point short time without any danger contamination. The great achievement the author was, thought, that the frequency had now been brought down about 500, that, instead having use the difficult and troublesome sparking gaps source high frequency current, rotary generator used. Some Metallurgical Advantages Sheffield crucible practice the really essential feature the killing fire the end the operation. For some time the steel lies the crucible per fectly tranquil state, the tiny particles slag, float- ing the top, being removed button the time casting. high frequency melting the metal very turbulent condition; the convection currents the steel are violent that there great difference level the top. That, urged, tended prevent the elimination very small slag particles. one switched off the current and left the metal tranquil state, the heat capacity small and the temperature the surrounding space little above the atmospheric temperature that, soon the current shut off, the metal begins cool down very rapidly. There the great advantage, however, high fre quency melting that, there contamination from furnace gases and carbonaceous material the cru cibles, was possible start with quite pure mate rials, inclose the whole apparatus vacuum and haust the air, practically slag being formed. possible, therefore, manufacture steel without hav- ing any slag introduced, and that case the turbulence the molten metal would not difficulty. From the crucible maker’s point view that question has considered rather carefully, added. Mr. Campbell, reply, said that Professor Desch had referred the convection currents the furnace, general term which meant the violent disturbance due convection the electrical field. That was princi- pally due electrical effects. had recently carried out some interesting experiments that connection be- cause some people supposed that that violent current would cause oxidation excessive degree. They had recently been melting aluminum foil paper large quantities, and was interesting see that the metal being made would rise about in. the crucible. formed part sphere. The center the melt was least in. higher than the side. the case steel was in. higher. the case aluminum foil the oxidation loss was very low, because the sphere which had referred was covered with skin, and the same happened the case the steel. There was skin film oxide the surface which was not broken any extent. They had succeeded melting fairly large quantities aluminum without oxidation, with much less oxidation than ordinary crucible furnace. Professor Desch had dealt with the most interesting question the crucibles, stating that when crucible cracked did not matter hecause the metal was held the backing behind it. That was sometimes the case. the crucible went before the backing had had time get heated against the crucible went through The Iron October 20, = a ' his the bottom, but the damage was not excessive. experience several lots 300 400 lb. steel had gone through the bottom the crucible. sometimes ran against the coil, but was immediately chilled against it. could usually got off the coil, but not there was difficulty cutting one’s circle out the coil and repairing it. The Question Temperature The president inquired how long was possible hold charge about the furnace. pre- sumed could not held for very long because the cooling was relatively rapid. Mr. Campbell replied that apart from metallurgical questions and dealing purely with the question tem- could kept hot without difficulty for least quarter hour. was not referring Dench’s experimental and laboratory plant where only lb. metal was dealt with. The heat insulation was extraordinarily good. Special insulating sand was being used, but good deal depended what material that nature was employed. They were working part- with plumbago crucibles for high-speed steel, and were also using plain crucibles with backing ganis- ter silica sand, which would not keep anything like well zirconium. With plumbago crucible and good lining zirconium, there was good heat the furnace the metal kept hot for quarter hour. Incidentally, however, there was neces- sity that because the current could always reg- ulated any way one liked. large number very small castings were being poured the furnace body could taken away cast with and another put position and melted while the first one was being used for casting. Temper-Brittleness Nickel-Chromium Steels ITH the aid Carnegie Research Fellowship, Dickie, Glasgow, has been investigating the Royal Technical College, Glasgow, magnetic and other changes concerned the temper-brittleness nickel-chromium steels, and his explanation temper- brittleness is, briefly, follows: When a steel susceptible to temper-brittleness is ooled slowly from a high tempering temperature, a portion the carbide, which exists that temperature solid solution the ferrite the steel, separates out, giving definite modifications magnetic properties specific resistance This also results, moderate oling rates, contraction and softening, shown ! pecific volume and hardness tests When, however rate extremely slow, the steel expands hardens again—relatively the moderately cooled tate and this is evidently due to the formation of a rk of carbide round the grains, producing, by its dominant effect on the coefficient of contraction influence increasing the resistance penetra- on, increase specific volume and hardness Deposition carbide from solid solution ill not, in itself, induce brittleness in the steel. It i nly when the rate of cooling is sufficiently slow to ow of expulsion of the carbide to the grain, boun- daries that brittl develop Dr. Hatfield, director Brown-Firth Research Laboratories, said did not think the experimental work and the results obtained coul