The Iron Age 1921-04-07: Vol 107 Iss 14

2ON New York, April 7, 1921 VOL. 107: No. 14 Heat Treating Plant at Nash Motor Works Refining and Carbonizing Furnaces as Well as Compound Mixing and Conveying Equipment Conserve Labor and Increase Accuracy of Work roller bearings, a plant unit recently completed for the Nash Motors Co., Kenosha, Wis., has sev- Outstanding features in the equipment are an heat treating furnace, a mixing and conveying system for handling carbonizing ompound and four double-oven oil-fired carbonizing T's be used exclusively. for the heat treatment of eral points of interest. electric r Double Carbonizing Furnaces Heated by Oil Automatic imns indicates furnace temperatures. Corrugated steel wall furnaces. The design of the plant and the nature of the equipment are such as to reduce manual labor to : minimum, and greatly to increase the possibilities for accurate work. Designed and constructed by the George J. Hagan Co., Pittsburgh, the heat treating furnace, which is entirely automatic in its operation, is the first installa- tion of its kind. It is especially adapted to the harden- ing of small parts. The roller bearings to be refined are received in a feed hopper by chute from a magnetic Separator. From the hopper they are fed at intervals by a motor-driven feed wheel into a hoisting bucket serving the furnace. When the weight of the hoisting bucket reaches a predetermined amount, a weighing device trips and stops the motor. The bucket is then automatically raised to the top of the furnace, where it delivers its contents through a trap door into a charg- ing chute. As the door is counterbalanced, it closes shut automatically immediately after the charge has passed through it. Square in walls of sheet cross-section, the furnace has exterior steel and interior of fire brick and sil-o-cel lining. Six tilting buckets, arranged in zigzag fashion one above the other, convey the roller bearings from the top to the bottom of the furnace during the process of refining. The material is passed through at a uniform rate, and in dropping from one scoop to the next is thoroughly mixed. The buckets and their supporting shafts, as well as the elements which fur- nish the heat, are made of nichrome, an alloy able to withstand the intense heat which obtains during the operation. A 1-hp. General Electric Co. a.c. motor drives the train of gears, the tripper chains and the pulleys which control the mechanical operations of the furnace. Each operation is so timed that it takes place at the proper interval in relation to other operations. Periodic Charging of the Heat-Treating Furnace The hoisting bucket delivers a charge into the fur- nace every 74% min. The time of each heat is 45 min., there being six tilts from bucket to bucket during that period. The shafts carrying the buckets extend through the walls of the furnace, each being fitted with a 895 «thi te Beds —— ee 896 crank on one side and a counterbalanced weight on the other. A tripper chain driven by gears from the motor is fitted with fingers which engage the cranks at timed intervals, tilting the buckets momentarily so that their contents are passed to the buckets immediately below. When the cranks are released the buckets are returned to normal position by the counterbalanced weights on the other end of the carrying shafts. In a similar discharge of the furnace is opened and closed to permit the contents manner the door of the bottom bucket to drop into a concrete quenching Two com- partments have been provided in the tank, so that charges may be quenched in either oil or water, a trap tank located immediately below the furnace. under the discharge door being manually adjusted to direct the charge into either compartment, as desired. Each half of the tank is equipped with a chute down which the charge is conveyed to a bucket. At timed intervals the bucket is raised and automatically dumped into a receiving tray resting on the floor adjacent to the tank. Connected circuit, the heating elements of the furnace have a maximum consumption at full load of 36 kw. into a 440-volt single-phase a.c. The thermocouples & Northrup recording regulator of the potentiometer type, which automatic- ally controls the temperature, and also limits the power consumption to the actual requirements of the material being heated. are connected with a Leeds The normal refining temperature used for the roller bearings is between 1475 and 1500 deg. Fahr., but by adjusting the regulator any. desired Not only is the furnace to adjustment, but the rate of travel of material through the furnace may be altered, temperature can be obtained. temperature subject Automatk Small Bearings through Vertical Cross Sections at Right Angles to Each Other THE IRON AGE ing Furn: Parts The hopper at top, predetermined to that out at the one bucket and finally April 7, 1921 and the size of the charge varied, by adjusting automatic weighing mechanism. The furnace is new and there is no past experie: on which to gage its length of service, but it is . mated that it will not require relining for at least years. Access to the interior may be gained by unl ing the top of the furnace shell. Carbonizing Done in Oil-Fired Furnaces Four double-oven oil-fired furnaces built by Strong, Carlisle & Hammond Co., Cleveland, are to carbonize the roller bearings. The furnaces constructed complete in the manufacturer’s plant, that when delivered at Kenosha they were practi ready for operation. All that remained to be was to remove the wooden skids fastened to the and to make one air and one oil connection for « furnace of two ovens, as all castings, brick were permanently assembled before shipping. total shipping weight of each furnace was 60,01 The purchase was handled through the Federal] chinery Sales Co., Chicago. and Heavily insulated, and encased in a cast-iror the furnace walls are of brick, 13% in. thick. A result of the insulation the iron shell is practical room temperature when the furnaces are operating 1675 deg. Fahr., thus indicating a material savin; fuel. The working tile of the furnace is provided three fire clay ribs running lengthwise of each the carbonizing boxes rest on these heating process. The problem of handling the charges was solved William Silcock, plant engineer, Nash Motors Co., wh adapted a Lakewood Engineering Co. elevating truc! to the work. The bed of the truck consists ribs during elevati two long fingers whic! into the interstices betw the ribs of the oven, a lectric Heat-Treat thus may be withdrawn af . fo Hardening F , ee the boxes have been depos Such as Roller ; , ited across the ribs. Ord pieces, charged narily, a battery of eis ovens would require a of four men, who would « sume about twenty pass at intervals from next below bottom, minut being all the while subjected to in unloading and load heat from the electric heating *each furnace. Throug! ee See use of the elevating one man does all of the wo unloading and charging Horizontal Cross Section single furnace in from to three minutes. 1 labor-saving scheme also serves heat, as unloa takes two minutes or following which the fur door is closed until the t returns three with another incidental advantage rib design is that it the floor tile of the fur from wear. In loading unloading by means of truck, the carbonizing are lowered to and from the ribs instead of ing shoved and dragged a fork, as is the us method. minutes charge. How the Furnaces are Heated Each furnace oven }5 heated with three Stro! Carlisle & Hammond (0w- pril 7, 1921 COOLING ROOM on £8 ER OS THE IRON Plan of Heat-Treating Plant, with Line of Mezzanine Floor Shown at SSS i—Four double-ove carbonizing furnaces, with future furnace at B C—Electric heat-treating furnace, with two future furnaces at D b Elevator for contents of carbonizing boxes. F—Elevators for mixed coarse and fine compounds G—Packing stations H—Final fine and coarse compound hoppers serving packing stations J—New fine compound hopper K New coarse compound hopper. L—Magnetic separator M—Chute to electric furnace \ Elevators P—Pyromete room, 8 x 16 ft Q—Office, 8 x 11 ft. essure oil burners, all three of which feed from side of the furnace. The air for the burners, eheated in a tank over the furnace ports, is sup- ied for combustion at a steady pressure of 1 Ib. a Spencer turbo-blower. To obtain complete mbustion the flame from the burners enters a com- tion chamber below the working tile. The heat— the flame—rises along the sides of the tile and iks through it, being reflected on the work from the ls and arch of the furnace. The arch of each oven provided with ribs running crosswise over the ribs the working tile. These arched ribs tend to keep heat circulating in one direction and to pocket in parallel channels, at the same time increasing radiating surface of the arch. After the furnace up to working heat the middle burner is shut off. Because of the expeditious method of loading and un- iding the boxes, heat losses from the ovens are iterially reduced. The drop in furnace temperature erages less than 250 deg. Fahr., and it requires about nin. to bring the oven back to working temperature er the hot boxes have been removed and the cold es charged. Each oven is provided with two thermocouples, one ugh the front of the arch and the other through center of the back wall. Temperatures from these iples are recorded on a, chart by a two-point Leeds Northrup graphic potentiometer. The chart gen- lly shows two coinciding red lines, indicating uni- m temperature throughout the oven, which is 4 ft. le by 6 ft. deep by 22 in. high. The advantage of form heat is that each carbonizing box is case rdened to the same depth and there is no spoiled rk, such as obtains in ovens with “cold spots.” A Leeds & Northrup automatic signal system sup- ments the recording potentiometers. When the perature of a furnace is below normal, a blue trie light is illuminated; at normal a white light vs, while above working temperature a red light nes. A clock dial has been provided on each fur- e so that the hands may be set for the time of rting and completing a heat. lhe carbonizing furnaces are located in a lean-to, h is separated from the heat treating building per by a corrugated sheet wall extending down from roof to a point just above the furnace doors. This angement tends to keep any escaping heat—as for tance during charging—out of the working room. ling stands for the hot boxes are also located in lean-to, for the same reason. The position of stands and their construction are such as to permit r being loaded and unloaded by elevating truck n the workroom. The average time of carbonizing is 9 hr. from a id furnace and 7% hr. from a hot furnace, and it is ve noted in this connection that the saving in time ugh the truck method of charging and unloading R—Space for proposed tool-hardening furnaces M)xi1g |} Device rrr rs ry > , ryy TT, rrr VID YOO ITT IIIT IG Cross Section of Magnetic Separator and Discharge Chutes and Hoppers for Old and New, Fine and Coarse Carbonizing Compound i—Magnetic sepa rator with double screen for coarse and fine com pound B—Chute for conveying roller bearings to electric heat-treating furnace materially increases the working capacity of the ovens. It is estimated by the Nash management that if hand labor were used, another double-oven furnace would be necessary to turn out the same amount of work. The carbonizing capacity of the four furnaces is ap- proximately four hundred sets of roller bearings (13 bearings per set) a day, while the electric furnace refines 175 to 200 sets in that period. The plant has been laid out to provide for the installation of an addi- tional double carbonizing furnace and two more electric furnaces, which will insure a total daily output of 500 carbonized and refined sets of roller bearings. Ingenious Scheme for Handling Carbonizing Compound After carbonizing boxes have cooled they are dumped into a bucket elevator and their contents are carried up to a revolving magnetic separator and screen, furnished by the Magnetic Mfg. Co., Milwaukee. In this device the roller bearings are separated from the carbonizing compound and discharged into a chute leading to the feeding hopper of the electric furnace. At the same time coarse and fine compound are sep- arated and delivered to different chutes, while dust is carried off to a cyclone and discharged by ehute to the floor. New coarse and fine material are added to the old compound through two hoppers and chutes which connect with the discharge chutes for the screened coarse and fine compounds respectively. Each of these chutes is equipped with a mixing device so set as to AGE 897 tan em 5g age * Kitabe & iets Beak ce ce ag my? rab | mix the new and old compound in the proportions de sired. The mixed material passes by gravity to the fioor, where it is picked up by bucket elevators and lifted to the final hoppers and chutes serving the box- packing stations. art } Carbonizing compound is stored in bags on a mezzo- The switch nine floor above the packing benche new com- railroad from a track When a next to the pound is delivered by arrives, the floor is lifted alongside the plant. shipment continuous sash mezzanine Organizing Advisory Committees Organization of advisory WASHINGTON, April 5. Irom business mittees and trade organizations to ymmerce 15 announced. A. W. perate with the Department of C pro- satisfactorily, it has been SI Chicago, publisher of System, and former ! 1 of the conservation division of the War In- ries Board, is working with Mr. Hoover as a volun- 1 in assisting in the organization of these com- ( is 1 subcommittee from the Chamber of Commerce of the United States, which will give it eas s to the selection of committees from trade asso- tions. While the iron and steel trade is to be repre- ented through the advisory committees, it probably will not be included in early discussions. It is the view f some officials that the iron and steel is so well organ it j others, with itself in maintaining ized that it is more capable than one or two exceptions, to take care of its export business. ind increasing Industrial Cost Association The subject of “Idle Plant has been selected for discussion at the April meetings of the sec- A paper on the Facilities” tions of the Industrial Cost Association. subject is being prepared jointly by T. W. Dinlocker, assistant comptroller S-K-F Industries, Inc., New York, and A. W. Wainwright, works auditor S-K-F Ball Bearing Co., Hartford, Conn. Copies of the paper will be distributed at the April meetings for reading and discussion. The discussions will be recorded and for- warded to the central office for digest; the whole thing will then be printed and distributed to the members. M. F. Simmons, General Electric Co., Schenectady, N. Y., president of the association, in a letter to the membership on March 28, announces that A. A. Alles, Jr., has volunteered to act as permanent secretary, giv- ing the association his undivided attention. “He has THE IRON AGE April 7, 1921 and the bags are taken direct from the railroad car On this floor also are located the hoppers into whi the new coarse and fine material are discharged for mixing with the screened compound, and the final hop pers which deliver the mixed compounds to the packing benches. method of handling Mr. Silcock, who conveying This compound was works out by also designed all of the mixing and equipment with the exception of the magnetic separator. tendered his resignation as secretary of the Faw Machine Co., which they have not seen fit to acce} He has, however, been granted an indefinite leave of absence, and is now on the job for us at Pittsburg! The association’s headquarters are in the Peoples Ba Building, Pittsburgh. Stoker Manufacturers’ Association The Stoker Manufacturers’ Association will hold annual meeting this year at the Red Lion Inn, St bridge, Mass., May 24, 25 and 26. For some time engineering committee has been working on a unive) coal analysis. It has also given considerable thou to the subject of a standard minimum setting heig for each type of boiler. These matters, together many others of considerable interest to the associat will be brought up and discussed at the meeting Named Commissioner of Patents WASHINGTON, April 5. Thomas _ Robertso1 Maryland has been named by President Harding Commissioner of Patents. It is claimed that there considerable opposition to Mr. Robertson and that contest may develop in the Senate over his confirn tion. At the annual meeting of the Cleveland branch the National Metal Trades Association, held March A. W. Foote, the Foote-Burt Co., was re-elected pres dent; P. A. Geier, P. A. Geier Co., was elected v! president and E. J. Stahl, Baker R & L ! was elected treasurer. The following new exe tive committee was named: Franklin Schneide! Van Dorn & Dutton Co., C. J. Fitzpatrick, Cleveland Worm & Gear Co., C. L. Collens, Reliance Electric Co and George D. Kirkham, Harris Automatic Press ‘ Open-Hearth FurnaceWaste Heat Utilization’ Coal Saving Equivalent of Recovery from Furnace Gases— Boiler Design an Im- portant — BY G. R. HE term waste heat is inclusive of the total heat left in gases of combustion when they have served their primary purpose of roasting, reducing, oxi- ying or heating in industrial or metallurgical furnaces kilns. Furnaces employing regeneration or recupera- yn commonly have left in the gases of combustion, iving the furnace, from 35 to 55 per cent of the total eat available in the fuel fired. Non-regenerative fur- ices may have as high as 80 per cent of heat in the fuel escaping in waste gases of combustion. Kilns, oil lls, glass tanks, water gas etc., all present, n account of the amounts and temperatures of escap- » gases of combustion, amounts of waste heat that re not only recoverable but that give returns which ili net from 25 to 75 per cent in one year on the tallation cost of the equipment. It is to be noted that prior waste heat boiler in- tallations had to do with waste gases at temperatures f 1600 deg. Fahrenheit and higher. It had hitherto n considered impracticable to generate steam com- iercially with gases below this temperature. For iste heat boilers prior to this time the accepted eviation from hand-fired types was an increase in the ras passage area. The work of C. J. Bacon, formerly am engineer Illinois Steel Co., South Chicago, dem- strated that for gas temperatures under 1600 deg., gas passages should be decreased and as a corollary sets, velocity of gases increased. Source of Gases from an Ope? Hearth I “nace Typical Heat ita heat (ingots).. 7 tons Hot pig iron.. 12.75 tons Cold pig iron 57 tons Iron scrap . 6.10 tons Steel scrap 32.50 tons Ore 14,200 lb Limestone 100 lb Dolomite ,265 lb Fluorspar 762 lb Silicon (10 per cent) f lb rged at producers 3.7 tons ut 9hr. 25 mi nt of w te gase 13.0 percent of waste gases fror ‘ e! 1.200 deg. F yf « i] ; 10.800 B.t.u 6.0 percent 8 per cent 1.2 er cen Where the Gas Comes From ras-producing elements of the charge are the n with 4.35 per cent carbon, 0.85 per cent silicon 1.75 per cent manganese; the limestone with 42 nt carbon dioxide: and the coal with the following 60.10 pe er eo 1.36 pe cer gen 1.18 per cent ren 10.97 per cent phi 1.42 per cent h 8.43 per cent iré 3.54 per nt lhe steel scrap charged is considered a neutral com- being essentially of the carbon and metaloid of the steel produced. The dolomite and fluor- contribute negligible amounts of carbon dioxide he gases. The ore charged, averaging 89 per cent ‘ic oxide, is significant in that the oxygen available erein for combining with the carbon of the pig iron ‘es the amount of air with its nitrogen diluent, erwise required for oxidation. In determining the amount of gas available per ir for steam generation the authors analyze the ‘n-hearth practice of the plant and show finally a tal of 7509 Ib. of gas for each ton of ingots produced ton? *Abstract of a paper presented before the Western Society f Engineers, Nov. 15, 1920. Item—Temperatures a MCDERMOTT AND F. H. Feature WILLCOX by the furnace. The analysis and sources of this quantity of gas are shown in the following table: Analyses of Total Waste Gases (Dry, No Air rounds per Dilution) Item Fri 1 of Ingots By Weight By Volume CO Charge 308 P Cc" Ps Coal ] 40 S45 “ : I t er cent Ne Charg : No 0a l Commi n 441 = is98 (2.6 pe r 50.5 per cent H,O Coaiand Steam ‘ s Total , The CO, content of 13 per cent in the stack gases as compared to 19.2 per cent in gases from charge and coal undiluted with air indicates an addition of air of 17.5 per cent to the gases. This is in part supplied through the ports and in part by leakage at the doors, ports and checkers. The indicated addition of 47.5 per cent air to 7509 lb. gas will total 3591 Ib. of air per ton of ingots, giving 1848 lb. CO,, 833 lb. of oxygen, 7651 lb. nitrogen, and 768 lb. moisture, or a total weight of gases of 11,100 lb. Per hour we have 88,500 lb. of gas. As an approximate check on these quanti- ties of gas one may divide the total carbon in coal, pig iron and limestone, or 503 Ib., by the carbon in one cubic foot of waste gas containing 13 per cent CO,, or 0.044 lb. This gives us 91,000 Ib. per hour. At 1300 deg. Fahr. there are 26,000,000 B. t. u. in the waste gases, as against 60,000,000 B. t. u. in coal charged, or 43 per cent of total heat charged, equiva- lent to 2400 lb. of coal per hour. As will be seen, 1270 lb. of coal equivalent can be recovered per hour in a waste heat boiler. Radiation and Convection Many experiments have shown that the heat ab- sorbed by radiation is proportional to the fourth power of the absolute temperature difference between the radiating surfaces. Contrasting a stoker-fired boiler with combustion chamber at 2700 deg. Fahr. (3160 deg. absolute) with waste heat boilers at 1300 deg. Fahr., temperature (1760 deg. absolute), the ratio of absorption by radiation would be 10.5 is to 1. Ordinarily about 65 per cent of total evaporation is by radiation and 35 per cent by convection, so that on a 600-h.p. boiler 7,025,000 heat units are absorbed by convection and 13,050,000 heat units by radiation. In the waste heat boiler but 1,300,000 heat units can be absorbed through radiation, leaving 18,700,000 to be absorbed by convection. Obviously the rate of heat transfer by convection must be, for the waste heat boiler, 2.75 times as great per square foot of heating surface. Even hypothetical ratio does not state the handicap imposed upon waste heat boiler heat absorp- tion, because the heating surface exposed to the direct heat of the furnace is less than in the case of a direct fired boiler. Obviously for a given gas weight, starting in with initial temperatures of 2700 deg. Fahr. and 1300 deg. Fahr. respectively, passing through or past an identical heating surface of a boiler, and having identi- cal exit temperatures, the net amount of heat ab- sorbed by convection by the heating surface must be much greater for the waste heat boiler with initial temperature of 1300 deg. Per square foot of heating surface of the boiler, therefore, the heat transferred by convection must jump to a figure hitherto considered impracticable. This point of view is not always appreciated. It about as this 899 f ; | Whit SY: rs oe ~~ Fete a _es” \4 A ; 4 aie ae 900 is not infrequently felt that, since a low temperature waste heat boiler gives but 70 to 80 per cent of builders’ rating, the heat transfer rate is low. Actu- ally it is very high. An increase in heat transfer rate is accomplished by an increase in velocity. Waste Heat Boilers and Their Tubes The trouble with the usual fire-tube boiler, especially when used for waste heat applications, is that the area for the passage of gases is too large and there is not sufficient length of travel for the gases. These objec- tions are, of course, overcome by making a long boiler of small diameter or, what amounts to the same thing, dividing the boiler into two or more passes. The mat- ter of tube size is also a large factor and if the ques- tion of cleaning were not of such real importance, the tubes could to great advantage be as small as locomo- tive tubes or even smaller. Waste heat boilers used in Europe in connection with gas engines have tubes of only an inch or so in diameter. By thus increasing the velocity of gases over the heating surface, the rate of heat transmission may be raised to a point as high or even higher than exists in the case of water-tube boilers. The three conditions conducive to high heat transfer are: (a) High velocity of gases. (b) Small size of boiler tubes. (c) Clean heating surface on both the water and gas sides. As usually built, the Bacon boiler consists of two vertical cylindrical shells, containing a large number of small tubes electrically welded into the heads. The diameter of the tube is kept as small as possible with regard to cleaning and the length is determined mainly rates Meeting of Southern Ohio Iron and Coke Association The April meeting of the Southern Ohio Pig Iron and Coke Association will be held at the offices of M. A. Hanna & Co., Cleveland, on April 18. The busi- ness meeting will be held at 9.30 a. m. In the afternoon, at 2 o’clock, there will be a joint meeting of the asso- ciation with the Cleveland Chemists and Ore Samplers, and in the evening there will be a triple meeting of the association, the Cleveland Chemists, and the Ohio branch of the American Institute of Mining and Metal- lurgical Engineers, at which moving pictures of the manufacture of pig iron and steel will be exhibited. Members of the Southern Ohio Pig Iron and Coke Association are desirous of having any representatives of users of lake ores with them at their meeting on the afternoon of April 18, when questions of great interest will be discussed. One Plant’s Use of Motion Pictures The uses which a manufacturer can make of moving picture films are set forth in an article in Moving Pic- ture Age by Harlow P. Roberts, advertising manager Emerson-Brantingham Implement Co., Rockford, IIL, the author basing his statements on experiences in his plant. The first films of the company took up the various steps in the manufacture and assembly of equipment. The workings of a large factory, the com- plicated machines and the accurate results obtained proved to be revelations to the uninitiated. The next set of films showed how the company’s tractors could be used. The manager owns a Universal motion picture camera and whenever he heard of a new use for the tractor he journeyed to the spot and photographed it. It is pointed out that the moving picture showing of such novel uses is much more satis- factory than attempting to demonstrate them at first hand, as the tractor is usually not performing when the prospective customer is present. Three reels were made on the operation, care and repair of the tractor, which not only helped present owners, but encouraged prospective ones as well, point- ing out to the latter the simplicity of the machinery. THE IRON AGE April 7, 192] by the space available and the friction loss. The object is to insure that the gases have a long trave! at high velocity. In some cases it is found desirable that the average velocity exceed 100 ft. per second, for the purpose of preventing dust from lodging and to give ; high rate of heat transmission. The waste gases ent: the gas box at the bottom of the first pass and th: go upwards through the tubes and into the transfe) flue, which directs the flow downward through the s ond pass. In some cases a third acting as an economizer. As a rule natural draft is not sufficient, becaus the gases leaving the boilers have been cooled to 4 deg. or 500 deg. in the attempt to recover as much of t! heat as possible. On this account, and because of th: tensity of draft required for operating the indust) furnaces and for drawing the bases through the boiler. becomes necessary to use induced draft fans. Wh: properly installed and driven, the fans prove a advantageous accessory from the standpoint of bet control of the operation of the heating furnaces. with correctly selected turbine drive the exhaust st: suffices to heat the boiler feed water. pass is provide Savings Expressed in Tons of Coal Details are given of tests made in 1918, as a res of which is was estimated that the possible saving (: recovery) per ton of steel produced was 200 lb. of co: As this is equivalent to about one-third of the amou of coal required in producers in making one ton of ste: the magnitude of the saving becomes very appar The authors give the fuel equivalent for the first s months of 1920, month by month, varying from 79 tons in January to 9710 tons in May. The averag: the six figures given is 8790 tons per month. The advertising features of the films are kept in th background and hence audiences in motion picture th aters and other assembly places are receptive. Educational and industrial films are also show: the employees for entertainment and improvement Moving pictures taken of the employees’ picnic ha helped morale. Drop Forge Meeting in Chicago For the annual joint convention of the America Drop Forge Association and the Drop Forge Supp Association, which will be held this year in Chica June 22, 23 and 24, the following joint committee in charge of entertainment and general arrangement for the convention has been appointed: For the American Drop Forge Association: Samue! M. Havens, chairman, Ingalls-Shepard Forging © Harvey, Ill.; W. E. Crocombe, Ajax Forge Co., Chi cago..; Thomas P. Octigan, Octigan Drop Forge © Chicago. For the Drop Forge Supply Association: C. Hallgath, chairman, Western sales manager N. & Taylor Co., 208 South La Salle Street, Chicago; A. |! Guilford, manager Chicago office Ajax Mfg. Co., Ch cago; R. S. LeBarre, general sales manager, a! division, Interstate Iron & Steel Co., Chicago. Previous meetings have been held as follows: 1° Atlantic City, N. J.; 1919, Pittsburgh; 1918, Buffal 1917, Cleveland; 1916, Philadelphia; 1915, Pittsburg! 1914, Chicago; 1913, Detroit. HH To what extent cleaning influences production a! quality is the subject of the prize story contest ranged by the Oakley Chemical Co., 22 Thames Stree! New York. The winner is to receive $500. Twenty eight others will receive less cash prizes. Stories ar to be written from the viewpoint of one in the meta textile or other industry and the contest will clos: July 1. The judges will be: Edward K. Hammond, associate editor Machinery; John H. Van Deventer, editor Industrial Management; Clarence Hutton, tech nical editor Textile World Journal, and C. F. Radley editor Oakite News Service. ril 7, 1921 AIR-COOLED SLAG POCKETS »emovable Type Permits Ease of Handling and Saves Labor Experience with water-cooled and other types of pockets for open-hearth furnaces have led to nerous designs, the success of which has not always commensurate with the expenditure and the cost upkeep. In types having inserted water cooling es back of a 4%-in. wall, there is no assurance that method will be effective, for should the water ise to flow the scouring action and the heat of the ig may prevent the further use of the pipes. Because this possibility the cooling pipes have generally been back of thick walls, thus lessening the cooling fect. The arrangement of water-cooled buckstays will Plan and Cross Section at Left, with Longitudinal Section Above, Show Makeup of the New Slag Pocket. At right is shown the appearance after front wall has been pulled down ice the same effect as inlaid cooling pipes, but will only local cooling. A renewable slag buggy has used for this purpose, but due to its height it re- es the capacity of the pockets, and it is stated that method of wall support and construction causing leakage proved an objectionable feature, while the h first cost usually prohibited its use. Various other designs of pockets, such as plates | with buckstays lined with 4%-in. walls, with inside s and floor 4% in. to 9 in. thick, supported from outer walls and bottoms by a layer of sand, have tried, but it is claimed with little success. Under ‘ various plans the slag was cooled, but due to the hods employed it remained in a solid mass fused to walls, and had to be dug out with sledges, bars picks, or with a slag gun. New Design to Overcome These Difficulties solve this problem, the Whalen patented re- ible air-cooled slag pocket, built by J. A. Gabriel Cleveland, is designed to allow the slag to nd and to contract in cooling, cracking it into ‘s and making it flaky, thus avoiding difficulty in val should the entire mass of material be too heavy pulled from the chamber with a crane. The is built inside the ordinary slag pocket, the of the latter being shown in light lines in the ving. The brickwork rests upon a plate sufficiently ng to carry the slag load, the whole being supported eams. The bottom of the pocket is given a surface ind to cover rivet heads and to facilitate the laying e pocket floor. THE IRON AGE 901 Side and back walls are 4% to 9 in. thick. The first three courses of the walls are made with every other matched brick at right angles. Alternate spaces of plain 4%-in. and staggered walls build the pocket up to the open air passage under the two top courses. The 9-in. walls project to within % in. of the stationary chamber walls. The two top courses are not cemented to the stationary wall, but the lower course is cemented to the pocket walls. Consequently air cannot enter into the pocket through this seal of two courses. The front wall is sealed tight to the stationary walls. Inserted in the side wall are angles to facilitate the removal of the pocket, as these hold the brick away from the stationary walls and guide the pocket walls when being loosened up and down. The vent pipes are inserted in each side of the front wall. Slag pull-out hooks are laid in the floor. It is stated that the pocket can be built cheaply of brick and scrap material by any stone mason. How the Pocket Is Removed To take out the slag, part of the front below the front wall arch is removed and the top courses of un- cemented brick are removed from the slag _ pocket. The crane hook is then attached to the front cross- beam and moved up and down, at the same time pulling out. When the pocket seems free the crane hooks are attached to the slag pull-out hooks and the pocket is drawn out. Removal of the slag pocket is facilitated by having the pocket taper to a smaller width at the back than at the front. The principal feature of this pocket is that no heavy walls are used. The whole pocket is cooled by the cir- culation of the cool air that comes in under the floor and passes completely around and up the side and back walls to the air passageway under the top courses of brick, leaving by way of the vent pipes. In cooling the slag contracts enough to free the side walls and breaks up into large chunks, making the slag flaky around the sides, as shown in the photograph. The slag from one 100-ton open-hearth furnace equipped with these pockets was removed by four laborers in less than 24 hours. The deposit measured 10 x 15 x 4 ft. in each pocket. One-half of the slag came out from one pocket in one solid chunk. The labor saving, as compared with ordinary practice in a stationary pocket, has been calculated at 24 man-days at $6.75, or $162 each time the slag pocket is cleaned. The Westinghouse Airbrake Co., Wilmerding, Pa., has announced a reduction in wages, affecting all ex- cept salaried -employees, effective April 1. A similar reduction in prices on finished products of the company is to accompany this change. The company had planned upon a complete shutdown, but at a meeting of the department heads late last week, it was decided to operate the plant at about 50 per cent capacity. H. I. Gardner and E. W. Gardner, identified with the electrical department of the Lowellville, Ohio, plant of the Sharon Steel Hoop Co., Sharon, Pa., have or- ganized the Mahoning Mining & Mfg. Co., which has been incorporated under Ohio laws with a capital of 250,000. EE IIe nema R = 902 MEASURING FURNACE GAS* New Device Giving Reliable Results—Compari- son With Other Methods BY D. L. WARD AND R,. S, REED This paper is the result of a study, in 1919, to de- termine how much surplus power could be produced through the proper utilization of the entire gas flow from the two furnace stacks at the Federal Furnace Plant, South Chicago, Ill. Obviously, the problem was to measure the flow of gas through the main beyond the point where the amount necessary for stove opera- tion was removed. In all probability, blast furnace New Measuring Ga Furnaces Device for Blast Diagram of the from gas is the most difficult gas to measure, because of the high moisture and dust content, and the widely fluctuat- ing flow from the furnaces. This wide fluctuation of flow forbids the acceptance of any one group of flow readings as indicative of normal operating conditions. A study of the conditions showed that a recording device on gas flow was necessary. As the gas at the point of measurement had passed through wet washers, and accordingly was saturated with water and con- tained considerable dust carried past the scrubbers in the form of sludge, no form of Pitot tube could be used, for this sludge would quickly plug the dynamic and static holes, spoiling the gage readings. An even more serious objection to the use of Pitot tubes was the impossibility of accurately measuring the cross- sectional area of the gas main on the plane of Pitot- tube installation. Given an absolutely clean gas and a perfectly circular pipe, it would be safe to assume, through measurements of the pipe diameter, that the main was of a certain cross-sectional area. But he contipyal depositing of sludge and the fact that the main was fabricated from riveted sheets led us to discard the idea of using Pitot tubes for this service. The Venturi tube ws considered, and had there been a sufficiently long straight run of gas main to accommodate a tube of the required size (72 by 28 in.) such an installation would very likely have been made. A plate with a sharp-edged orifice was eventually accepted as it the. characteristics of a Venturi tube, requires less space, and is much easier and cheaper to install. Besides, sludge deposits do not tend to affect the diameter of a sharp-edged orifice as greatly as the throat of a Venturi tube, and it is reasonable to assume that sludge deposits are more easily removed. Accordingly a plate with a 43-in. (109 em.) orifice was installed in the 72-in. (182.9 cm.) main in connection with an indicating-recording-inte- grating meter. This instrument has been in run over 10 months and has given no trouble to operate or main- tain. A sensitive legible record is obtained from every fluctuation in gas flow. When originally installed the instrument was de- signed to operate on a maximum differential pressure across the orifice of 3 in. (7.6 cm.) of water. At this differential the flow rate would be about 3,000,000 cu. ft. (84,950 cu.m.) per hr. Later, when two furnaces were put in operation, it was found that a greater amount of gas would be produced, so the float was arranged to operate under a maximum differential of 4% in. (11.4 em.) of water. yas is then ? possesses all *From a paper presented at the February meeting in New York of the American Institute of Mining and Metallurgical Engineers. The authors are respectively general superin- tendent Federal Furnace Plant, By-Products Coke Corpora- tion, Chicago, and with the Semet-Solvay Co., Ashland, Ky. THE IRON AGE April 7, 1921 The flow of gas through a properly designed orific: takes the same form as through a Venturi tube, but owing to the sudden change in cross-sectional area. the smallest section of gas occurs after having passed through the orifice. As shown in the illustration, th gas flow having an initial velocity of v, and a corr sponding static pressure of p, is forced through a: orifice and its velocity increased to v2 This increas in velocity, which is maximum at the point of greatest contraction xd, produces a static pressure p, lower tha p. In other words, a certain proportion of the initia pressure p is converted into velocity pressure due to th constriction introduced in the gas main.- The formula that has been developed is as simp: and reliable as necessary for determining the flow of gas through an orifice. It is as applicable to Ventw or Pitot tubes if the proper value for c is substitut: Q = CAV29H where Q flow of gas, in cubic feet per second; GC coefficient of flow: A area of orifice, Venturi throat, or pipe secti Pitot tube, in square feet; T %< 226. xX h H rx 2D where T absolute temperature of gas, in degrees C h differential pressure, in inches of water; P = absolute pressure of gas, in millimeters of cury ; D specific gravity of gas referred to air. [Expressing P in inches of mercury, instead of millim: T 9x h the value of H becomes s EDITOR. } rx 2 For Venturi tubes C, the most important an variable value, has been generally accepted as 0.95 0.99; it usually varies directly as the ratio of th: throat diameter to the upstream pipe diameter. Fo. Pitot tubes, the value C varies anywhere from 0.5 to unity due to the many different types of Pitot tubes used and their relative location in the gas flow. Il some cases traverses of the gas main are made i! order to obtain an average velocity reading; in others, the tube is permanently located in a certain position and the value of C adjusted accordingly. In order to test the accuracy of the gas-mete1 installation, it was decided to calculate the theoretical yield of gas from the furnace and run a short test diverting the entire gas flow through the boiler-hous« gas main. To do this, it was necessary to shut off tl gas flow to stove burners and then measure the creased gas flow through the orifice. The method em- ployed for calculating the gas yield was that outline by Richards.t Let L limestone charged per day, in Ib C charged per day, in |b.; F flue dust collected per d mse pig iron produced per day, in Ib.; A earbor analysis, per cent; B COs by analysis, per cent The percentage of carbon is found in the flue-dust coke, and pig-iron and the per cent CO, in limeston in the latter case due account is made for the MgCO content. The theoretical amount of carbon convert into gas may then be found thus: Carbon converted to gas, lb (0.27281 LB CA) — (FA + PA). It is then necessary to analyze the furnace gas a! calculate the amount of carbon in each cubic foot o! gas; generally this value will be between 0.012 anc 0.0155 Ib. (0.0054 and 0.007 kg.) per cu. ft. If this value is divided into the figure obtained from ¢ formula, the theoretical gas yield per day may be ca! culated. At the Federal plant these analyses and ca culations were used with the production figures ove! 24-hr. periods; the resultant figures were very ©0! sistent, and, during tests made with the orifice mete checked the gas-flow figures very closely. Sometim: the 24-hr. results were not in line with the flow-mete! figures; at other times, the two methods checked within several thousand cubic feet of gas per 24 However, when the figures were tabulated, averaged, and compared over one or two weeks’ period of time, the results were very satisfactory. They show value of blast furnace gas flow tests and records cov- ering a considerable period of operation, and the com- parative inaccuracy of gas flow tests of short duration. +Metallurgical Calculations, Part II, Chapter III Mannesmann Oblique-Rolled Seamless Tubes’ i | Dependence Upon Obliquity of Rolls for Hollowing of Solid Ingots—Torsional Forcing of Material Away from Center — Relation Between Roll Taper and Hollowing Produced : N 1886 the first patent for making tubes by the the point of contact of the roll with the work there is oblique rolling process was granted in Germany an attempt to drive the surface particles of metal in ‘ to Dr. F. Koegel in behalf of Mannesmann Brothers the longitudinal direction. Though this tendency can wf Remscheid. Mil!s based on this principle were at first have hardly any other effect than to wear off © ected in several places in Germany, Bohemia and_ the surface, it leads to the basic principle of oblique j iter in Wales, but in spite of strong financial support rolling. ‘i did not produce the results desired. This was In Fig. 3 is shown this process substantially as al iinly because it was attempted to produce finished carried out in practice. The work A is held back by 4 ibes and pipes in the one process from the solid ingot the taper on the rolls and its surface particles are an idea which later had to be discarded because the urged forward by the rolls. This action affects not ilt could not be achieved commercially. The chief only the surface particles, but extends also to the : lrance appeared to be the production of homogeneous’ interior of the work; the material is drawn out of the ty terial in which the finest molecular coherence of middle and pushed spirally forward toward the ex- irticles should exist. Cracked and piped materia! terior. : } It appears that the early assumption was incor- NT ta fe {7p A | ee rect which held that for proper hollowing it is neces- " — i isinB} = [+o }? sary to oppose a mandrel to hold back the core of the te = Ly-4 material. This was originally supposed by the in- 4 TY veosp ventors and also by Professor Reuleaux. The hollow oe : : piece is produced even without using a mandrel. In c Fig. 1. Operation of an Oblique Roll rolling work the mandrel serves the purpose only of + bringing the material to an equal wall thickness, and . nues to cause trouble even in the improved appa- of smoothing the inside. It is chiefly useful in the > to-day employed. final passage of the last part of the work through the |. \s a result of these early experiences the oblique rolls. i at ng mills are now used only as roughing mills, and As already mentioned, this method requires homo- i eo ars rolled hollow upon them to a wall thickness geneous material. The individual fibers must be co- ¢ ipproximately 1 in. Ingots or billets are used of herent so that they shall flow in response to the pull ad weight that a tube of 25 to 40 ft. in length may iN ide from a single piece. To produce from thes« j tively thick-walled cylinders a finished tube with thickness from 0.1 to 0.5 in. a finishing roll a also an invention of Mannesmann Brothers, is Fiz. 3. Formation of a H This is the so-called “pilgrim-step” process, esr Tania tn eee ee i mes known as the Perrin process. The “face ke, bevelled disk, oblique rolling mill, similar to s a n the first Mannesmann patent, has been further : . d by R. C. Stiefel, a German-Swiss resident in | ted States. Merely fundamentals of the oblique , process will be here discussed, based upon a from the surface. This circumstance becomes the more ’ vy Professor Reuleaux in 1890. notable the thinner the walls are to be that are hollow sider a piece of work A, Fig. 1, supported on rolled. “This structural quality of the material ex- d oblique to its axis the roll B. which can plains why the oblique-rolling process has been so d ted while pressed against the work. The latter Well established for rolling copper tubes, and in that i eld that it may both rotate and move longi- field has been so extensively used, even for rolling | thin-walled tubes. i ’ ee a Theory of the Oblique-Rolling Process r fommecos |) |r xamee OD, : ' t r to } a ——> V Cos In Fig. 4 are shown the rolls of ordinary design 0 } a See a. for the Mannesmann oblique rolling mill, whether for 4 TE catininanel — tient the smallest application or for hollow rolling of solid ! { th) L = Ves, bars 3 to 6 in. or more in diameter. With a body i edd - length of 20 in., the maximum diameter D of the roil i 2. Operation of a Pair of Oblique Rolls is 14% in. xes eross. The force which causes the rotation Besides this size, roll trains are con- angle of inclination is taken such that tan a = % to structed with D 17% in. and D 21% to 25% in. ; ily. If the roll B is turned, its revolution is At the right side of the maximum roll diameter D itted to the work A, but at the same time an (Figs. 4 and 5) is the working cone, with a length L movement of A is produced. If wv be the and an inclination of its sides equal to the angle a. ferential speed of the roll, the revolution of the This working cone is of greatest importance in the . s v cos 8 and the speed of the longitudinal dis- hollow rolling and the theoretical consideration of the | ent v sin 8, where 8 is the angle at which the rolling process is especially concerned with it. The | d travel of the work comes from the pressure the roll and the work. /w another roll is pressed against the other side work, whose axis likewise makes an angle § with the work, Fig. 2, we obtain through the opposed ire of the two rolls a definite movement and rota- ‘the work. But if the work is $0 held in a bear- that axial displacement is impossible, then at ral tract of Doctoral Thesis of Dr. Karl Gruber at Tech- ligh School, Breslau, Germany; published in full in d Eisen, Sept. 4, 1919, et seq. 1/18. A point of particular importance is the obliquity of the rolls. Each of the two equal rolls lies at an angle 3 to the horizontal, of about 5 deg. The center lines are therefore, as projected on the vertical plane, in- clined to each other by an angle 28 of about 10 deg. and intersect at the middle of the rolls. This projected point of intersection of the roll center lines on the vertical plane is called the central point M of the Mannesmann rolling mill. All measurements of length and breadth proceed from M, and vertical dimensions 902 904 are referred to the horizontal plane of the central point as the principal plane of the roll train. - The obliquity of the rolls affords an automatic feed of the ingot be- tw