The Iron Age 1922-03-02: Vol 109 Iss 9

VOL. 109, No. 9 Open-Hearth Furnace Design Calculations for Hearth Area. Depth of Metal. Incline of Parts and Velocity of Gases BY A. D. WILLIAMS* i pi 3 SIGN computations for an open-hearth furnace of the computation being to illustrate the formulas | a, ) lo not require any large amount of mathematical used and their application. ; : wwledge, for the principles involved are com- Reactions in the open-hearth furnace are well & ; ely simple. As in all other engineering and known. Their main effect, as far as the flue gases are propositions, it involves compromising a num-__ concerned, is an increase in CO, and the moisture con- s different requirements, and co-ordinating them tent, the latter in the first part of the heat, and the . right manner to secure a desired result. All ele- former during the boil and after adding limestone. The fie i? f the problem are closely inter-related, and fuel consumption will vary with the method of working i! if ti ‘ ‘ft , ‘ # a . HY ' 7 i , i x ei 7 a 0 i i 2 '@ i " , | } i - 4 $ Fig. 1. Gas and A Comt vit Sup f Alt a. i nd modifications at one point necessitate car- the furnace, etc., ranging from 485 lb. (220 kg.) per i responding modification through the entire ton when using molten pig, up to 770 lb. (350 kg.) per a mr) : . ° Z affects. ton and higher. The fuel consumption is not uniform or lish a base for departure, it has been as during each furnace cycle, from charge to charge, but a furnace having a nominal capacity of 100 varies about as follows: § . ig built, that it is to be fired with produce 4 . , he. Percentage Percentage the actual hearth area will be 650 sq. ft. of C of Fuel . . . . . . (Time) Consume itations will be limited to those required to —7 ho 6.0 the design lines. Certain factors may be more 17.0 15.2 +. e : 14.0 ‘ rarily fixed, without regard to current prac- Le 0.4 ther they are desirable or not, merely for e of furnishing a working base, the purpose 100.0 100.0 12, Newark. N. J. For the case in hand it is assumed that the fuel ~ -- old en a eee et ae eng « is ad at ee ee ee mb 3 Ss ee 578 THE IRON AGE consumption will be about 660 lb. (300 kg.) per ton, converted into producer gas of the following percent- age composition: H:, 12.10; CH, 2.60; C.H,, 0.40; CO, 21.78; O:, 0.02; CO:, 5.68; H:O, 3.82; N:, 53.60; having a thermal value of 142 B.t.u. per cu. ft. (1261 calories per cu. m.) low value. The heat capacity of this gas, and the air supply required for its combus- tion and for the products of combustion, are shown by the curves, Fig. 1, which are similar to those shown on seneueateveannaans Table I Combustion of Producer Gas Percentage of Gas Volume Volumetric 3 l B.t.u napiapaganians — Composition Per 100 Products of Com- of Gas, “t. oO Cu. Ft Oo plete Combustion er Cent tlemen of Gas Required COs Hed0 No* 3.548 6.05 sie. 2maO. 3820 2,55 5.20 2.60 2.60 20.80 ; 0.60 0.80 0.80 2.40 21.78 X 343.6 10.89 21.78 ose Oe. 0.02 Pe 2 fata - 02 res po 0.08 5.68 P : gute w -— 5.68 2 29 Sa 53.60 Penk swae es sae —er 100.00 »ooe 22.92 30.86 21.92 144.48 Theoretical air supply 22 113.60 cu. ft. per 100 cu. ft. gas. *Assuming atmosphere to consist of 80 per cent Ne and -0 per cent O Products of Combustion Air Supply of 100 Volumes of Gas Per Excess lam - ——__ ———, Cent Volume Ail Oo COe2 HeO No Total 113.60 0.00 0.00 80.86 21.92 144.48 197.26 136.32 22.42 1.54 80.86 21.92 162.66 219.98 159.04 45.44 9.09 30.86 21.92 180.83 242.70 204.45 YO.SS8 18.18 30.86 21.92 217.18 288.14 page 1225, THe Iron AGg, April 29, 1920. Table I gives the combustion and air supply data for this gas. One pound of coal produces 70 cu. ft. of this gas, its specific weight being 0.07024 lb. The products of combustion, with 40 per cent excess air, weigh 0.08241 lb. per cu. ft. At the maximum rate of working, the gas will be burnt at the rate of 188 cu. ft. per second, requiring 300 cu. ft. of air, and the products of com- bustion will be 451 cu. ft. These are the volumes at 32 deg. Fahr. and 29.92 in. barometer. As the volu- ve rve of an Inclined Jet metric correction for pressure is comparatively small, it will be neglected in the computation, and tempera- ture corrections alone used. As the capacity of the furnace is to be 100 tons, the metal volume will be 523 cu. ft. With a hearth area fixed at 650 sq. ft., the approximate depth of the bath will be: ? ” d te 2.41 ft. a 650 As the bottom will slope toward the tap hole, and be banked at both ends and sides, the actual maximum metal depth will depend upon the way this is done. As there will be at least 12 in. of bottom, the depth to the brick will be about 42 in. from the sills of the charging doors, and the port sill or bridge will be fixed 6 in. higher, making the total maximum depth that the flame must drop below the port, 48 in. The brick lines of the hearth will have to be fixed 29 in. of metal March 2. outside of the bath area of 650 sq. ft. Theres inside width between walls will be made 16 f; (5 m. 40) and the length between port sills 44 ; (13 m. 50), giving an area of 726 sq. ft. (67 ; If the length is cut to 42 ft. 8 in. (13 m. 00) ¢) will be reduced to 700 sq. ft. (65 m.’ 00). width might be reduced slightly by increasing th: There are advantages in reducing the span of t! as well as disadvantages in making the furn long; but it is possible that a length of 46 ft. 00), with a width of 15 ft. 3 in. (4 m. 650), gi area of 701 sq. ft. (65 m.* 11), would be satisf The temperature in the heating chamber 3275 deg. (1800 deg. Cent.) for the gases, th being 100 to 200 deg. (55 to 110 deg. Cent.) coo! // / Fig. 3. The Inverted Parabola of a Flame in Making the bath from 270 to 450 deg. (150 to 250 deg. Cent cooler. The height of the chamber may be ap) mated by Yesmann’s formula: | A Bs QO, V Bet he In which, he the thickness in ft. of the moving gas lays Vt the volume of gas in cu. ft. at t deg. (Cent perature ; B the width of the furnace in ft.; A a coefficient which varies for each value of h in accordance with the following table :* ——Values of B - 6 ft. 9 ft. é i 16 ft 2.36 é 2.43 3 2.41 5 9°29 boon 9 8 245 od wet we bo bo bo HO bo Do bo bo bobo 99 ‘ a. . vio The metric formula, together with many others used herein, will be found in “The Flow of Gases in Fur- naces,” by W. E. Groume-Grjimailo. For the case i hand: Or Qo (1 + qt) = 451 X 7.606 = (= $7 m’ 14) t 3275 deg. Fahr. (= 1800 deg. Cent.) B 16.4 ft. (5 m 00) or 15.25 ft. (4 m 650) 1 3430 cu. ft i 2.37 and 2.34, approximately, The formula may now be written with these values follows: 2 = ee ames hy (3430)? Vase iam For B 16.4 ft. he 2.37 - (16.4)* K 1800 ° @ 4 949 _ For B = 5.25 . - ‘ (3430) \ Gib25)" x 1800 This will be the distance from the surface of the bath to the center of gravtiy of the roof segment. It will give an approximate height of the skewbacks, above the door sills, of 5 ft. 4 in. (1630 mm.) for the wider chamber, and 5 ft. 7 in. (1700 mm.) for the nar- rower chamber. With a chamber area of 700 sq. ft. (65 m.) the chamber volume will be approximately 5087 cu.ft. (144 m.*) for the wider chamber and 5280 cu. ft. (149 m.’ 50) for the narrower chamber. The gases will remain in the chamber approximately 1% seconds, which, with a temperature drop of 360 deg. (200 deg. Cent.) per »72 second means a temperature of approximately +‘ deg. (1500 deg. Cent.) for the gases leaving the cham- ber. Referring to the curve, Fig. 1, and allowing for a drop in calorific intensity of about 360 deg. (200 deg Cent.) it will be seen that a preheat of the air and 4s of between 1470 and 1830 deg. (800 and 1000 deg. ) Sas : : 1 of A *Using metric units throughout, the table of va! .# follows: ———vValues of B— 1.00 m. 2.00 m. 0.00 1 3.6 3.57 9° yy h will be required. 2, 1922 Allowing for a possible loss nerature in the necks, cinder pockets and up- the checkerwork will be proportioned to supply a oe < distance the jet of flame must drop below the or port sill, to permit the sintering of the bot- is been fixed at 48 in. (1200 mm.). in n t Thy angle of the two jets. + t \f 2200 deg. (1200 deg. Cent.). An assumed velocity of the air and gas will fix the re- The higher the assumed velocity, the less the resultant angle will be, e further beyond the center of the chamber the f maximum depression of the jet of flame. 1 velocities, in addition, cause the incoming end chamber to work cold and the outgoing end to fl f the chambers shall work, as nearly as possible, mly. y+ Ol, while the desirable condition is that both High velocities for either the gas or the an reduced port areas, and high velocities for the no is +h the ports. amber walls. 1 1 products of combustion, which in turn call necreased draft depression to pull the gases This draft depression creates a acting to pull air in through the valves, flues At the same time, it is necessary e sufficient draft to draw the waste gases out of hamber and down through the checkerwork, but wer this draft depression, the less the tendency luce air leakage or infiltration. \ \s the flame has to drop 48 in. in one-half the 46-ft. 00) length of the furnace, an angle somewhat than 10 f the jet. deg. must be allowed for the tra- Yesmann’s formula for this case is: v? sin®a 59 + fi H anges 9f cussmennngees 2a tm iddle ordinate of the parabola, in this case 4 ft.; resultant velocity of the two jets uniting to form the flame ine of the resultant angle of the two jets; vitational constant 2 xX 32.2 64.4: emperature of the gases within the ch ture of the gases in the jet imber ; emper n a furnace is heating up, the stream of flame follow the roof until the interior of the cham Industrial Conditions in Belgium SHINGTON, Feb. 28.—The revival of Belgian in- luring the last quarter of 1921 was largely , being caused by a combination of temporary , especially the decline of German competition, tine Commercial partment Attache Cross in a cable to of Commerce. Since Jan. 1 this im- ent has been abruptly checked, especially in the glass, coal and metallurgical industries. The lrench exchange, price reductions on British ron and steel, and American window glass, have efly responsible for the reaction, and Belgian icturers are finding drastic measures necessary ne ng foreign competition. ‘gotiation in the coal mines and window glass Wage reductions are Coal prices have been cut from 6 to 10 francs to meet the British competition, and price re- ns in window glass are being considered to meet erican cuts. Colliery stocks are increasing, and lency toward the combination of coal mines and e of collieries by metallurgical interests is con- Coke production has been greatly stimulated foreign demand and all ovens are working to eb. 1, 18 blast furnaces were operating as com- th 15 a month previous. These are now pro- 646 tons of foundry iron and 2470 tons of basic “4 hours. The increased production has re- a marked price reduction which has been istened by the low British quotations which irred in all metallurgical lines during the past eks, representing decreases ranging from 10 r ton on pig iron to 50 francs on billets and Belgian prices of open-hearth steel gen- THE IRON AGE 579 ber becomes raised to a temperature sufficient to per- mit it to drop, and the drop of the flame is an index of the progress made in heating the furnace. It is likewise desirable to be able to sinter the bottom, when the furnace for any reason may be cooler than usual, or the ports eroded. The temperature of the jet of flame, t,, may be assumed as 3275 deg. (1800 deg. Cent.) and the gases in the chamber as 1475 deg. (800 deg. Cent.) — t;. Velocities of v 50, 65 and 80 ft. (15, 20 and 25 meters) per second, tried out in the formula and solving for sin a, give a resultant angle as follows: Fo 50 ft. per second a 18° 3 65 ft. per second a 14° 1 $0 ft. per second a 11 In solving to obtain these angles: ti 1475 459 ts 1834 ti 3275 1475 1800 H t 2g @ X $2.2 64.4 The formula can now be written: H { vst " a x 1834 64 4 ~ LsS00 which becomes asa _ 15.92 sii a = a > - - Va For 2 50 ft. per sec., sin a 0.3184 For 1 65 ft. per sec., sin a 0.2449 For 2 80 ft. per sec., sin a 0.1990 Should t; be given a higher value than 1475 deg. (800 deg. Cent.) the angle will be less. Two com- ponents may be selected to suit the resultant angle and velocity, but this cannot be intelligently done until the pressures available for impressing velocity upon both the gas and the air have been approximated. For the air, the pressure available will be entirely due to the chimney effect of the system, diminished by the re- sistance to the flow of the air, unless a fan is used. The same pressure is available, in the case of the gas, plus the pressure in the gas main, which is more or less under control through the steam blower on the producer. To determine this chimney effect, it is neces- sary to arrive at the regenerator height. erally are down 1 franc per kilo. From the Belgian standpoint, further reductions are both probable and essential, owing to the persistent low offers of British pig iron and semi-finished productions in the local centers. The Sambre et Moselle works have recently received an order for 40,000 tons of rails from Argentina, and Brazil has placed an order for 32,000 tons with the Usines de la Providence. Other important rail orders have been received from Holland and Bulgaria. Corporations Granted Extension of Time WASHINGTON, Feb. 28.—Commissioner of Internai Revenue Blair has granted a general extension of time to domestic corporations for completing returns of in- come for the calendar year 1921, the fiscal year ended Jan. 31, 1922, and the fiscal year ending Feb. 28, 1922 The extension is conditional upon the filing of tentative returns with the Collector of Internal Revenue on or before March 15, April 15 and May 15, 1922, respec- tively, accompanied with at least one-fourth of the estimated amcunt of tax due, together with a statement setting forth the reason why the return cannot be com- pleted within the prescribed time, and a formal request for the extension. This permission was granted on the plea of corpora- tions which insisted that it was a physical impossibility to make the returns on the date required in the revenuc act of 1921. The tentative returns must be so labeled and only the name and address of the taxpayer and the estimated amount, if any, of the tax due need be stated. The law provides for a levy of 6 per cent in the event of a deficiency in the first instalment. = ae sp cn nelee tars ob be ci ere = ehh ig, Leos « ré 7 c 7 os te? ; < 4 ‘ >= > oe ' ots, Y. =2 aa 7 a ~ Se SEAS AR eT AO Ras ae. Share Baha. aS ~ P< co oeyncannaeA seb tae “ane SET eter ‘e on NE ae lle it 2a : eT ete alpen arta enero ha a Granite City Batte Illinois and Operat HUCVCOGENDLANELDONDAEOONUEDERAUONEGL IT LeNCGANADUDANANONRAUECRDASONEDONELIORCEOIEACDECASUSONEDEOAENONCEEENORACLACCADONESLESAHEDTENLY -Product Coke Ovens uce Metallurgical Coke from Coals—Design and esults Secured - DITTO ULCNELAESEUOMEREAUNETOOREGONCEULOCENLUONNODEEULOLECEUAURLOREETELOLCATUENLOLEREEDOONEAUTUSDOEOED OAUHLOUEADDONEEEOLANUDUEROLEEEREOURSAORREDOEL EUOTEOLIONEALECASOUEONOS Editor’s Note: The successful production of metallurgical coke from the high volatile coals of the Illinois and Indiana fields has long been regarded as impossible. Yet by-product ovens, designed for that very purpose, have been in operation for a year. The blast furnace of the new plant of the St. Louis Coke & Chemical Co., Granite City, Ill., was described in an illustrated article in THE IRON AGE of Jan. 6, 1921. The first published description of the Roberts type coke ovens of that company is appended below. The author is consulting engineer of the St. Louis Coke & Chemical Co., and also of the American Coke & Chemical Co., of which the former is a sub- sidiary. The outstanding difference between the Roberts oven, as constructed at Granite City, and other by product installations lies in the baffled structure of the wall, which permits the heat to be absorbed from the heating gases in the combustion chamber at a higher rate than in the flue type of oven. The heating walls are always maintained at a temperature above the heat requirements of the coal, eliminating the variation in temperature resulting from heat absorption by fresh coal, and thereby preventing the volatilization of. the binding elements. PEE IG iron was produced in and about St. Louis in P some quantity before it was produced in the Chi- cago district and other places that have since become famous, as iron producing centers. What pig iron was produced in this district was mostly from native Missouri ore with charcoal as fuel. The pro- duction of iron gradually decreased, however, as other producing centers, such as Pittsburgh, the Valley dis- trict and Chicago, grew up, until it ceased entirely. In the meantime St. Louis became one of the largest iron melting towns in the United States, and depended entirely upon iron shipped in from other districts. In view of the fact that St. Louis was contiguous to one of the largest coal deposits in the world, and that freight rates on ore were on an equitable basis with other iron producing points, there seemed to be only one thing that prevented St. Louis from becoming a permanent iron producing center, and that was the in- ability to utilize the coals contiguous to it. Previous to the time that the Steel Corporation was formed, John W. Gates and Levi Z. Leiter of Chicago became interested in the production of coke from these coals on a large scale. Mr. Leiter carried out some early experiments that indicated that it was possible to use these coals if apparatus that could be economically operated could be devised. Unfortunately Mr. Leiter died before the conclusion of his earlier plans, and the development work on the use of Illinois coal for the production of metallurgical coke lay dormant for sev- eral years. Development work was undertaken again, however, HUULOUNULGODDOOONROUADOUUEEDLODDODOODEOONAT SDDEED UORUROMEDAOAENRE OE HEDNAOEDEE® and finally concentrated itself around the organization built up by Arthur Roberts of Chicago and his asso- ciates, and crystallized in the construction of the St. Louis Coke & Chemical Co. plant at Granite City, Ill. This plant was completed and put into operation in January, 1921. It consists of one 500-ton blast furnace, designed by Freyn, Brassert & Co., Chicago, and 80 Roberts by-product coke ovens, arranged in two bat- teries of 40 each. The furnace is of standard design of the following dimensions: Height, 86 ft.; hearth, 17 ft.; bosh, 20 ft. 6 in.; bosh angle, 80 deg. 5 min. The furnace has been successfully operated since its installation on coke made from Illinois and Indiana coal. It is operated in con- junction with the National Enameling & Stamping Co., which has ten open-hearth furnaces and produces practically all of the steel used in its enameling and stamping departments. The iron is transmitted from the furnace to the open-hearth furnaces in the hot metal form in Treadwell ladles, and the furnaces are heated with coke oven gas and tar. As it is anticipated that the successful coking of Illinois coals will lead to great expansion of the stee! industry in the St. Louis district, the plant at Granite City was laid out for an ultimate daily capacity of 300" tons of pig iron and 8000 tons of’ coal, consisting of six blast furnaces and 320 ovens. The initial 1” stallation is so arranged that the two units closest ' gether are now built, and the extensions will be mace in both direction from these units. . at. As stated, the coke ovens are arranged in two bat 580 rch 2, 1922 of 40 ovens each, supplied from one coal storage aving a capacity of 1900 tons. All of the equip- of the coke oven plant is standard, the only arity of the plant being the design of the coke themselves. efore building this plant, the only installation of ts ovens that was used for producing coke from volatile coal for blast furnace purposes was a of 24 at Dover, Ohio, in conjunction with the \. Hanna Co. furnace there. The practice estab- at that point was the basis for the Granite City The Dover ovens used the common regenerators reheating the air, similar to the old Otto-Hoffman but aside from the regenerative feature the ovens actically the same as in St. Louis. onsiderable interest was created when it was an ed that the Granite City ovens were to be ned with recuperators made of silica brick and ing the entire space underneath the ovens, similar .e individual regenerative type of oven. A brief iption of the ovens will clearly show how the de- differs from what has been known as common tice in coke oven construction up to the present nstruction features of the oven are shown clearly skeletonized model view. It will be noted that ecuperators are divided into two individual in- dent sections, and occupying all of the space rneath the ovens with the exception of the dividing The waste gases make two passes in each of sections and each section is made up of 16 flues tiers each. The gases pass through the flues, and r flows countercurrent upward on the outside of flues. The entire recuperator is constructed of brick. h oven has a capacity of 600 cu. ft. of coal, and erage width of 14 in. The coal is charged within foot of the top of the coke oven chamber, through harging holes. The products of distillation are 1 off on the pusher side through a single ascension and both batteries are equipped with duplex foul mains, so that the gas can be separated. All of fuel gas is introduced at the top of the oven, the ary gas being introduced at a point about 12 in. the coal line, and the secondary, half way down 1! ail veill primary and secondary gas headers or mani- at the top are independent. These headers are ngular in shape, with a partition in the center, de being for the primary gas and the other side the secondary. The primary gas goes through a Coke Being Pushed THE IRON AGE 581 {-in. hole lined with fire clay tile, having a %-in. hole In It. Air coming out of the top of the recuperators rises through the center wall to practically the top of the coke oven chamber. There it is transferred across the wall and passes down through ports on each side of the port through which the primary gas is introduced. All of the air is introduced at this point and our com- mon practice is to introduce only 50 to 60 per cent of the gas required for the carbonizing of the coal at the orifices of the primary gas. The balance of the gas enters through the secondary ports, which are reached by ducts coming from the top of the wall through the center wall, and enters the combustion chamber through inclined slots in the side of the brick. All of the products of combustion, accumulating in the upper sole flue, are allowed to go through ports, regulated by slide brick, into the lower sole flue, where they are all brought to the end of the oven and thence downward to the first pass into the top of the re cuperator. After passing through the lower section of the recuperator they are discharged into the waste gas offtakes, in which a butterfly valve is inserted to regu late the draft on each oven. There are seven ducts in the concrete foundation supporting the oven structure. The air comes into these ducts from the ends of the foundations at both extremities of the battery, and passes through the ports on top of the first course of fire clay brick into the base of the recuperator. These ports have cast iron slide dampers over them to regulate the quantity of air. This has proved a very satisfactory way of introducing the air, because we have been able to main- tain the concrete work underneath the ovens at prac- tically atmospheric temperature, so that there have been no expansion problems involved in that part of the installation. In designing this oven the principal things we kept in mind were the fact that we wished to produce a large tonnage of coke, per dollar invested in the plant, and to simplify the operation of the ovens to as high a degree as possible. Therefore, there are no points in the oven where regulation of both air and gas or products of combustion is dependent upon a combina- tion of regulator dampers. The draft is regulated by the butterfly valve in the waste gas offtakes. The dis- tribution of the draft is regulated by the slide brick on the ports at the bottom of the upper sole flue. The amount of air going to each primary burner is regulated by the slide brick at the top of the wall, and the amount of gas passing into the wall at any one into the Receiving Car le oT gp er I a ir Poca pa - a pee eed ees a ae ee a ee ee te ns Tee pens rae came | l Tee ne emaeee ee es Seas net me atid THE IRON AGE point is regulated by the adjustment of the cocks com- ing off of the distribution manifolds along the top of the oven. The gas is regulated by drilling a predeter- mined size hole in the plug that goes into each in- dividual cock. These holes vary in size according to the width of the oven, and the quantity of gas that each oven gets is determined by the pressure carried upon the main header, based upon the well-known fact that a given quantity of gas at constant pressure will flow through a given size orifice in a unit of time. To vary the quantity of gas being burned per unit of time requires merely the changing of the pressure on the main headers, which is done by setting a governor instead of changing the sizes of the orifices in the in- dividual cocks. After having determined the quantity of gas required for a given coking time and having placed the proper size orifice in the cocks, the only function of the heater from that time on is inspection of burners to see that they do not become clogged. The secondary gas is regulated in the same way. On the ends of the gas manifolds there is an auxiliary pipe connection coming from a separate header, in which air at 1 lb. pressure is supplied by an ordinary high-speed blower. Our practice is to cut off the gas entering the Coke Discharge secondary gas ducts every 6 or 8 hr., and allow the air at 1 lb. pressure to pass through them. In this space of time there will be from 1/16 to % in. of carbon formed on the walls of the duct, which is 1% in. in diameter. As this carbon is red hot the admittance of air into the duct starts combustion immediately, and in the space of from 10 to 15 min. the carbon is all burned out. We do not consider that there is any heat loss from this, because observation shows that the temperature of these ducts is hotter at the end of the decarbonization period than at the beginning, and the products of combustion resulting from burning the carbon are hot enough so that there is no deleterious effect upon the heating conditions in the lower part of the wall. As a result of this practice, we have had no trouble from introducing the gas through the secondary gas ducts, and, by the arrangement used, it requires very little of the heater’s time, the only important thing be- ing that this operation is carried on regularly at stated intervals. The benzol equipment has not yet been installed at this plant, and we are using the lean gas for fuel with- out the benzol being taken out. Our experience showed at Dover that, when the gas was debenzolized, it was not necessary to decarbonize these ducts more than once every two @ three days. So the question that March 2, naturally arises as to the relative value of intro: gas into a coke oven wall at more than one poi its elevation does not present any operating diffi and in our opinion the advantages gained by means are worthy of serious consideration. The height of the walls of the Roberts oven js 9 in. The ordinary lean coke oven gas running in hydrogen necessarily burns with short flame. H by using the method of distributing and burning gas described, we have no difficulty in maintain); uniform temperature on the high wall, thereby get the benefit of the greater tonnage with narrower oven chambers. The brick work in the coke oven wall is of stay Roberts type, making a combustion chamber tha intercommunicating throughout its entire length, the exception of the baffles, partially isolating the 1 end burners. These baffles are put in to make it sible, by draft regulation, to compensate for the heat required to keep the ends at the same tempera as the balance of the wall. The action of the gas being introduced into a oven wall of this type is interesting. It has aly been assumed that, by satisfying the given quan of gas with all of the air necessary to burn it, Side of Ovens would localize the heat at the point of combustion. This is not entirely true, according to our practice, be- cause of the fact that only 50 per cent of the gas is introduced at the point where all of the air comes in. As it is necessary to raise the excess of the 50 per cent of air up to flame temperature, the latter is re- duced or tempered by the excess air; and as the point where the air and gas first meet is a mixing chamber, which might be termed a short flue, the rate of heat extraction is lower than it is further down in the wall. There is no question that by interrupting the flow of gas, as in this type of wall, the rate of extraction of heat from the flame is higher than in a flue structure. When we come to the point where the secondary gas is introduced, it mixes with the products of com- bustion resulting from the primary introduction, and the air at that point is diluted to such an extent that the rate of combustion is materially slowed down. All of this gas passes through the section of the wall in which it is being constantly impeded by that part of the brick which crosses the combustion cham- ber. We have found it to be an arbitrary problem whether either the top or the bottom of the coke oven wall should be carried at a uniform temperature, °F hotter or cooler; and it is our practice to carry the bottoms a little hotter than the top, particularly on the fast coking times. rch 2, 1922 THE IRON AGE 58a the Brick Form- Baffled Structure Heating Wall, Be- tion Through the Wall and Com- Chamber Construction of the Ovens Is Well Shown by Skeletonized Mode} 1e comparison of the function of this wall with ar problems in heat disposal or absorption is often nade with the air cooled gasoline motor. In this in- In This Sectio fins are cast upon the walls of the engine cylin- der to dispose more rapidly of the heat, as it is ab- | by the inner surface of the wall. In the Roberts ven this condition is reversed, that is, we might fins are cast on the inside of a cylinder wall Shown Corresponding Curves Representing (I) th Ideal Condi- tion with Heat Trans- as heat absorbing elements instead of heat ‘'T®d to the Coal at ng elements. Uniform Rate through By likening the checker brick combustion chamber ntire Height of Oven ; fins on the engine cylinder, with the fins exposed (1) the Heat Effect heating gases, there is a more rapid absorption Actually Present in eat than if the walls were smooth. While this Roberts Wall: (K. L gy is not an entire measure of the function of ..,4 Ry) Theoretical type of construction, it is a comparison that is jo.) cc to Whien th ting. / S i ; oven was designed to have a waste gas tem- ““**S Would Go if ture of 750 deg. Fahr. at the point where it left “ot Influenced by the wer pass of the recuperator, when operating the ‘onditions Existing in 15 hr. coking time. The operation of the plant the Oven ved the figures on which we based these calcula- ) be accurate, and when operating at the slower ng time the waste gas temperatures run very much r; that is, when operating on 18 to 22 hr. coking the waste gas temperatures are from 350 to 400 eg. Fahr., and by the same token, when operating at turn with new products of combustion; so that there is 2 13 and 14 hr. coking time, the waste gas tem- 4 continuous flow of heat of uniform temperature, wor Zz Ag Aff, Aff SLLLLLALY? YAS /A , ¢ppApSAAA A fo es go’up to 850 deg. Fahr. which is the reversed condition of a reversing type of this was the first installation utilizing a re- regenerator, and the average overall efficiency is just tor of this type, it was not our desire to seek as high as could be secured with a regenerative design. aximum gas economy, as there were some un- The oven is supported on two 18-in. silica brick walls factors that had to be worked out before the that are corbelled in at the top to bridge over the top gn could be adopted as standard. We now have of the recuperator, so that the expansion of the re- nformation, and feel that it will be possible to cuperator can be taken care of independently of the oven according to this design as economical in oven structure. If, in the future, it is found necessary sumption as any regenerative oven that has to reset the brick in this section of the oven, this can signed or put in operation to date. be done without interfering with the upper part of the When operating at the normal coking time of 15 hr., structure. eaving the top of the recuperator is heated to There are independent buckstays on the bulkheads erature of from 1670 to 2000 deg. Fahr. As this forming the insulating brick in front of the recuper- es up through the brick work between the two ators, controlled by screws from the main buckstays, so alls, it also increases in temperature to that that the position of these small buckstays can be placed ck through which it passes, increasing from at the required point, regardless of where the main 50 deg. Fahr., depending upon the operating buckstays go. The question of the difference in expansion between leat is not lost, however, because it is a closed ~ ate serreteioeamerenanete is going back to the heating wall on its re- (Continued on page 624) bet wi saney conerannenne sereptee w= es plac 5 AO AG ads Ses ac Bt 8 > | rR in OT a RR a i Sa a ata “ =p . THE IRON AGE March Motor-Driven Portable Disk Sander A 15-in. motor-driven, portable disk sander for use in pattern shops and wood-working plants in general has been brought out by the Oliver Machinery Co., Grand Rapids, Mich. It is suitable also for sanding hard rubber, fiber, leather, and in machine shops, for medium and light metal work. The machine is desig- nated as the No. 182 and is shown in the illustration. The disk is a steel plate 15 in. in diameter and is mounted on a disk shaft hub. It is removable for re- newing sand paper. The speed of the disk is 1725 r.p.m. The disk head is a one-piece iron casting, con- taining the disk, disk shaft, ball-bearing end thrust and exhaust fan and system, forming one complete unit. The table is 9% in. wide, 21 in. long and 37 in. from floor. It can be tilted 45 deg. down or 25 deg. up by the Disk Sander fo1 Wood, Metal and Other Material hand wheel shown, a graduated index being provided to show the exact angle of tilt. The table has a 6-in. vertical adjustment and can be swung to the right to permit taking off of the disk. The angle gage, oper- ating in the table slot, is graduated from 0 to 45 deg., both to right and left, for accurate setting. The machine is equipped with a combination gage to enable circular, segment and duplicating work to be done. This gage consists of a plate with a hinged strip pivoted to the bottom, which rides in a slot on the table. The plate has a series of holes to take center pins for circular work and the fence part of the angle gage for duplicating work. There is also a stop gage and segment pin for segment sanding which is oper- ated by a handle cast to the plate. An adjusting screw acts as a stop or set for amount of cut to be taken. The motor is single, 2 or 3 phase, 60 cycle, 110 or 220 volt alternating current or 110 or 220 volts direct current, coupled to the disk shaft. A 25, 30, 40 or 50 cycle motor can be provided at extra cost. The motor runs in ball bearings and rotates the disk shaft, but does not take load of thrust. A plug connector per- mits of attachment to any light socket. The switch is of the push button type, located as shown. Cireular work up to 15 in. in diameter and dupli- cating work up to 7 in. wide can be handled. Garnet- paper disks are provided for wood sanding and aloxite or emery-cloth disks for metal grinding and polishing. The exhaust system deposits the dust within the col- umn. The weight crated is 400 Ib. Blast Furnace Activities Carnegie Steel Co. now is operating 28 o{ blast furnaces, 27 on pig iron and one on spieg The latest addition to the active list is one of th stacks at the Clairton works, all of which hay down for about a year, and one at Du works. One of the Lucy furnaces whic! been making Bessemer iron will soon go on romanganese. LaBelle Iron Works recently start its second furnace at Steubenville, Ohio, and t} nace of the Wheeling Steel & Iron Co. at M Ferry, Ohio, will be blown in before long. The n of active furnaces in the territory bounded by town, Pa., Portsmouth, Ohio, and Warren, Ohio. | 60 out of a total of 140. Only five merchant fu, and 25 steel stacks are in blast. Duplex Hand Milling Machine A duplex hand milling machine for slitting rings of the step type has been placed on the 1 recently by the Superior Machine & Engineerin; Detroit. It is also intended for use in sawing babbitt-lined bearings for automobile crank sha for milling two keyways or slots at the same { any similar operation. The grinding surfaces are long in proport their width, which enables the slides to move without cramping. Sliding members can be c!: in position without disturbing the adjustment gibs. The machine is driven directly from the line but can be arranged for motor drive, in which ca The Table Is Op ated by the Har Lever S howt Through a Ra: and Pinion %4-hp. motor is mounted on a bracket at the bas ; the machine. On the end of the main-driving sa! there is a change pulley which is belted to an uppe pulley mounted on the lower spindle, as shown in ‘¢ ace ompanying illustration. The drive to the upper spi dle is through helical gears and a vertical shaft. The helical gears are hardened and run in oil. The spindles are of high-carbon steel and run in bronze bearing Graduated dials are provided on all adjusting s ; The table is operated by the hand lever, shown, tous! a rack and pinion. The machine weighs approximate 900 lb. ews Dilworth, Porter & Co., Pittsburgh, maker of and track equipment, plant of which has been ! several weeks, resumed operations Feb. 27. ch 2, 1922 THE IRON AGE 585 New High-Duty Drilling Machine new 20-in. high-duty drilling machine having a ty for driving a 1%-in. high-speed drill through has been brought out by the Foote-Burt Co., Cleve- I ? t is designated as the No. 23, and was designed ke the place of the former machine bearing the number. machine is shown in the accompanying illus- The features include simplicity in general de- there being no loose brackets or other bolted-on of Head and gehts Permits to Be in Shear tead of in Tension ind in the interior mechanism, which has re- d in the elimination of many parts.. All parts are ly accessible for inspection and adjustment. The f a telescoping screw under the table is also elimi- tiy ng levers being within easy reach from the the single screw provided permitting vertical idjustment of 12 in. without the necessity of pro- a hole in the floor. Control is centralized, all tor’s working position in front of the machine. ( design of the head and column permits bolts to ear instead of in tension. Bending stresses due drilling pressures are taken up by the rigid up- which is also reinforced by the head. It is i that this method of construction is better to the modern practice of using high speeds and eds than a design in which the upright is split tally at the point of maximum stress. The base, and jack-secrew support are all cast integral, intended to add to the rigidity of the machine. drive is by a single pulley through a friction no counter shaft being required. Nine spindle from 75 to 610 r.p.m. are provided, and three feeds, 0.006, 0.012 and 0.026 in. per revolution nind'e. Speed and feed changes are made liding gears, no clutches or sliding keys being Helical gears are used for driving the spindle, ting power to the tool evenly and smoothly. nd feed change gears are of heat-treated steel. hine has the “Footeburt” double rack feed to dle intended to eliminate side friction on the 'eeve. The svindle is counterbalanced by a The driving-shaft bearings are Hyatt or taver arings, Hyatt bearings being used for radial | the taper roller being for the combined radial t load. Heavy ball-bearing takes the thrust of dle. irts of the feeding and driving mechanism are inclosed. The speed change gears run in an oil bath and the feed gears are lubricated by a positive- splash oil system. The upper driving helical gears and other bearings are packed in grease, a sufficient supply being stored in caps to last several months. A gear-driven pump is provided for cutting compound. The principal dimensions are as follows: Center of spindle to face of column, 10 in.; nose of spindle to top of table, 285 in.; length of power feed, 12 in.; Morse taper No. 4; working surface of table, 20 x 16 in.; verti- cal adjustment of table, 12 in.; face of square locking table bearing on column, 10 in.; length of square lock- ing bearing on table, 12 in. The net weight is 2700 Ib. Hacksaw Machine Using Light-Gage Blades at High Speed A metal-cutting machine for medium-duty work, in- corporating the positive draw-cut principle and designed to use light-gage blades at high speeds, has been added to the line of the Racine Tool & Machine Co., Racine, Wis. It is known as the Racine Junior and is a moder- ately priced machine intended for the average shop. A production approximately double that usually obtained is claimed. The use of light-gage blades is permitted because of the automatic-lifting device incorporated. The lift is positive and takes place on the non-cutting stroke, giv- ing free clearance to the blade on the back stroke, under all pressures. This is said to eliminate drag back, heat- ing, bending and binding in the cut, effectively prevent- ing quick wearing off of the teeth of the blade. The feed is by gravity. An automatic knockout is provided to stop the saw when the cut is finished. The saw-frame guide holds itself automatically at any height and adjustment for wear is provided. The frame slides on V-ways, giving maximum bearing surface. The ma- chine is designed to take stock 4 by 4 in., although by simple adjustment stock up to 6 by 6 in. can be handled. The speed is given as from 60 to 100 r.p.m. and the stroke 6 in. The floor space occupied is 38 by 12 in. The height to top of the table is 20 in. and overall height 28 in. Blades 10 to 12 in., 21 gage, are used. The weight is 150 Ib. net. “Reducing Power Bills on Mine Fans with Synchro- nous Motors,” is the subject of a paper to be presented before the Association of Iron and Steel Electrical Engineers, by Frank W. Cramer, engineer of tests, Cambria Steel Co., and A. A. McDonald, chief engineer, Union Coal & Coke Co., at its regular monthly meeting to be held at the Chatham Hotel, Pittsburgh, March 18. The authors will show that with the use of a synchro- nous motor, together with a magnetic clutch, more than $500 per month was saved in driving a mine fan, which delivered 500,000 cu. ft. of air per minute. An- other phase which this paper takes up is the replace- ment of a steam engine by an electric motor. The meet- ing is open to all engineers interested in these applica- tions. oe : ) a sa ag RN MCI eS aN il 9 ee er Seen ea Mining and Metallurgical Engmeers Discuss Open-Hearth, Electric and Rolled Steel Problems at Annual February Meeting—Important Drill Steel Session—Enthusiastic Non-Ferrous Meetings N attendance which ranks among the largest was a feature of the one hundred and twenty-fifth m of the American Institute of Mining and Metallurgical Engineers last week, Feb. 20 to 23, in York, at its headquarters in the Engineering Societies Building. The symposiums on mining, o: eign oil possibilities, on petroleum and gas were unusually well attended. The iron and steel section hel, meetings generally regarded as some of the best; a feature was the unannounced appearance on the floor o! eminent British metallurgist, Harry Brearley. The sessions of the Institute of Metals Division were char. ? ized by liberal attendance and marked enthusiasm. A meeting of the committee on breakage and heat ment of drill steel recorded important progress in this field. The report covering the activities and busines: dition of the institute revealed a large increase in membership, the largest except in 1920, and a financial . tion decidely more satisfactory than in some years. The Sessions on [ron and Steel HE first of the two sessions on iron and steel, held Wednesday morning, Feb. 22, was in memory of Prof. Joseph W. Richards, who died last October. The chairman, Bradley Stoughton, spoke of Doctor Richards as for many years chairman of the iron and steel com- mittee and as one of the chief authors of the institute’s constitution and by-laws. The iron and steel committee of the institute had therefore decided to designate this session as one in memory of him as an old friend and benefactor. Due to the fact that several memorial meetings had been held and biographies printed, it was suggested that the testimonial at this meeting consist of those present standing in silent tribute to the mem- ory of Doctor Richards. Acid Open-Hearth Practice The most important paper on the iron and steel pro- gram was entitled “Acid Open-Hearth Process for the Manufacture of Gun Steels and Fine Steels,” by Col. W. P. Barba and Dr. Henry M. Howe. The paper, which covers 39 printed pages, is of large importance as a contribution to the literature of this subject and discusses the details of all phases of the process. It was presented in abstract by Colonel Barba. The chief cause leading up to the formulation of this paper, which is essentially a committee report growing out of the war, was pointed out by Mr. Barba as the sore need of finding some way to stop the rejec- tions of finished gun and other material, which devel- oped in 1918. These conditions are clearly presented by an introduction to the paper by Prof. Comfort A. Adams, chairman of the engineering division of the National Research Council, which is in part as follows: When this country went into the war, but two companies, the Bethlehem Steel Co. and the Midvale Steel & Ordnance Co., knew how to make steel fit for great cannons and at these concerns there were relatively few men who knew the whole art. Fortunately, certain of these men put their knowledge at the service of the Government, and proceeded to instruct the metallurgists at the arsenals and at various steel works. The then chairman of the engineering division of the National Research Council, Doctor Howe, suggested that this work might be facilitated, and the number of effective gun-steel makers thereby increased, if a detailed description of the best practice could be written, giving the reasons for the various steps, and issued with the indorsement of a committee composed of those who were evidently the most competent authorities. It was thought that something would be gained by a clarification of the subject, and something by the eminent authority of the members of the committee. To that end, the engineering division appointed a committee, consisting of the gentlemen whose names follow, to mention only those who retained their connection with it. At this time there were serious difficulties in the manu- facture for the Government, of aircraft and high-speed engine crankshafts, of certain ordnance forgings and of shells for both the Army and Navy. This committee was asked to study and report upon these, with a view to betterment of practice. There were indications that the source of some of the difficulties went back to the melting of the steel a production of the ingot. Hence, the committee first st steel melting and ingot production, in order to guide th: time manufacturers to an even larger percentage of production from the steel initially melted. The con referred to above was as follows: W. P. Barba, chairman, ordnance dept., U. § (formerly vice-president and general manager Midvyal: Co., Philadelphia). George K. Burgess, division of metallurgy U. S. B of Standards, Washington. Henry M. Howe, then chairman engineering divisio National Research Council. Kk. F. Kenney, metallurgical engineer Midvale Ste: Ordnance Co., Philadelphia. Dorsey A. Lyon, Bureau of Mines, Pittsburgh. . Theodore W. Robinson, vice-president Illinois Steel Co Chicago. A. A. Stevenson, Standard Steel Works Co., Philadelphia. Bradley Stoughton, then secretary American Institute of Mining and Metallurgical Engineers, New York. W. R. Walker, assistant to the president, U. S Corporation, New York. Frank D. Carney, Carney & Lindemuth, consulting « neers, New York. The committee deputed the authors of the paper prepare the proposed report, which they did forthwith. T was a few weeks before the armistice in 1918. TI was completed soon after, so that it represents the work o the authors in the autumn and winter of 1918, but its pub lication has been delayed by several causes, Anything like an adequate presentation of the con tents of this paper is not possible in these columns It embodies the results of a research into all phases of the metallurgy of acid open-hearth practice and the best opinions of the authorities on the committee. In his presentation of it Colonel Barba declared that it is impossible to transmit this metallurgical practice into the spoken word or the printed page. A broad idea o! the paper in his opinion was comprised in the state- ment that adequacy of melting equipment was essential! —an equipment which will insure the completion of all necessary reactions. With such equipment as a starting point, the following essentials