The Iron Age 1916-11-09: Vol 98 Iss 19

New York, November 9, 1916 ESTABLISHED 1855 WLLL!” LLMOOQLOMLLE AOA LD Y VOL. 98: No. 19 Measuring the Flow of Compressed Air A Curve to Facilitate the Calculation of the Weight of Air Flowing Through Orifices—Some Examples Worked Out BY THOMAS G. The problem of metering, with a reasonable degree of accuracy, the flow of air under pressure, is one that arises very often in engineering” prac- tice, and until recently has always been difficult, both in the method to be used and in the calcula- tions that are required. Proportional meters and displacement tanks have been used and are fairly accurate, but the equipment -necessary is very ex- pensive and the end does not often justify the means. The simpler meth- ods are the throttle disc and the pitot tube, but the great trouble here is to determine accurately the coefficient of discharge which will vary under varying conditions of flow In the last few years very exhaustive investiga- tions have been made on the flow of air through well-rounded orifices, and it has been found that with a certain shape of orifice the coefficient of discharge will remain practically constant over a wide range of conditions and is nearly equal to unity. This at once gives ' us a very accurate .nethod 7 ‘ of determining the quan- tity of air flowing and at the same time requires 10 0:99 098 O57 096 0% _ 053755 060 065 01 , very little apparatus. All eee the equipment necessary A Curve to Facilitate iS an accurate thermom- eter, a means of determin- Flowing Through ing t pressure on the two sides of the orifice and a standard orifice. All recent handbooks for fngineers give the shape of the standard orifice With 1 oefficients of discharge for each shape. Pr bly the most common case where it is neces to measure the flow of air is in the test- ng mpressors in order to determine the real Volu efficiency, particularly the larger com- pre such as the blast furnace blowing engines. eason that the standard orifice method is * more is probably the fact that after the data are obtained the calculation of the ne f air flowing is laborious and somewhat Ail) In order to facilitate this calculation, a ESTEP, JR. curve has been prepared, and by its use the calcu lation has beer very much shortened and reduced te simple arithmetic. It can be proved that the velocity of the air in the orifice, for a given ratio of pressures on each side of it, is given by the equation, WwW W ition of the Weig tandard Orifice A peculiar condition arises in relation to the pressure p, due to what is known as the critical ratio So long as the ratio of the pressure of the region into which the orifice is discharging to the initial pressure p, is equal to or greater than 0.53, the pressure p, in the orifice is the same as the pressure of the region into which the orifice is discharging, but when the above ratio is less than 0.53, the pressure p, takes the value 0.53 p in. absolute. and remains constant at that, no matter how much the pressure of the region int which the orifice is discharging is reduced. To illustrate this, assume that p, is 100 Ib. per sq. in. absolute and the pressure on the other side of the orifice is 70 lb. per sq. in. absolute. The ratio here is 0.7 which is greater than 0.53, hence the ressure p, in the orifice is 70 lb. But suppose that the pressure on the discharge side is 40 lb. per sq. Then the ratio is 0.4, which is less than 0.53, hence p, takes a value 0.53 p, or 53 Ib. per 1049 re ore oe pis co 1050 THE IRON AGE Novem sq. in., and no matter if the pressure on the dis- charge side is reduced still further, p, remains con- } lb. per sq. in. absolute. This means that the maximum velocity in the orifice is reached when stant at 0: the ratio of pressures on the two sides is equal to 0.53. In the equation for velocity given above, it is usually assumed that W, is e always so small compared to W, that this assump- tion introduces very little error. It is also assumed that the expansion of the air in the orifice is adia- batic. An examination of this equation shows that for a given pressure ratio all the quantities in the equation are constant except T. Hence let The weight of air discharged is equal to the area of the orifice multiplied by the velocity and divided by the specific volume, or ( { KT M j . ‘ 1 1 . . . - VY. is not easily determined, but for each value of - ; V _ there is a corresponding value for >» Where V, is the specific volume at the pressure p, and the tem- perature T. V, can be readily determined by the use of the simple relation RT V 144p Then the equation for weight may be written, C { K7 17 Vi : } (7) he curve of K has been plotted by choosing suc- cessive values of and solving for K and also find- ing the value of for each value of . | , For small differences of pressure, a curve has been plotted to an enlarged scale, in which the ratio of specific volumes has been neglected, for this ratio is so near unity that the error is very small. A few problems will now be solved to illustrate the use of the curve. Suppose air at an initial pressure of 100 lb. per sq. in. absolute and a tem- perature of 70 degrees Fahr. or 530 degrees abso- lute, is allowed to flow through a standard orifice, having a cross sectional area of 2 sq. in., into a region of pressure of 60 lb. per sq. in. absolute. : es a p 60 What weight is flowing? First = 100 0.6 1 which is greater than 0.53 so that p, is equal to 60 . P, i ° lb. From the curve, when — 0.6, K 1620 and Vv . 1.44, } j RT 53.34 « 530 ; V, = = 1.96 cu. ft. 144p, 144 Sx 100 Let the coefficient of discharge be equal to 0.98. Then bo 0.98 > CXA Xv RT 14 M 1X\ = ce 44 Cal 1.44 } 4.47 lb. per sec. Suppose that the conditions are th« the previous problem, except that the pr: region into which the orifice is dischar; per sq. in. absolute, instead of 60 lb. p 30 — (.3, which is less than 0.53. D, L100 equal to 0.53 p, and the ratio is then 0.53 ratio, K 2010 and 7 equals 1.57. As 1.96 cubic feet. Then the quantity d 9 op ~SCOD8 ( A Ki 144 (; y 1.57 b 1.71 lb. per sec. Take the same conditions as in the prey lem, except that the pressure of the re; which the orifice is discharging is 97 lb. p: absolute instead of 60 lb. Here the ratio 97 ae to 100 0.97, which is greater than 0.53. Us: ) curve plotted to the larger scale, from which w find that K 104. The ratio of specific volumes may be taken as unity. Then quantity flowing, 9 y _ CXAXVET 0.98 X Tqq% V 104 x 680 os o. hee - 1 < 1.96 — BV, | ’ 1.63 lb. per sec. From the above examples, it is seen how muc! the curve simplifies the calculation. Other uses will suggest themselves to the engineer, particular those who have a knowledge of the theory of th flow of elastic fluids. By introducing certain other factors in the equation, the curve can be made t apply to gases other than air. A word of caution might be given here in th use of standard orifices for measuring the flow air. The flow through the orifice must be constant if it is pulsating or fluctuating, a large error will result. In case the flow is not steady, it should be made so by means of tanks and throttling. Russia’s Iron and Steel Output Russia’s production of pig iron, semi-finished finished steel in the last two years, according L’Economiste Européen of Sept. 29, 1916, was as fol lows in net tons: 1914 19 Pig iron ‘ ; . 4,769,300 $,062,1 Semi-finished steel ; », 308,800 4,539,11 Finished steel 1,334,100 3.59 Central Russia is credited with over 70 per cent the total pig-iron output, the Ural region coming sé¢ ond. Central Russia also leads in semi-finished an¢ finished steel, making 60 per cent of the total sem! finished steel, while the Ural region made 20 per cen In 1914 Poland produced 269,500 tons of pig iron, o>"; 900 tons of semi-finished steel and 313,000 tons % finished steel. Belgium’s coke output for the first half of 191, 4 cording to a German source, was 408,812 metric tons The briquette and coal output was 1,077,735 tons * 8,478,732 tons respectively. Novet 9, 1916 THE IRON AGE 1051 y¥ RIFLE MACHINERY idle Drilling and Reaming Machines England Westinghouse Plant to the pressure for small arms by the warfare in Europe, rifle mak- intry is making rapid strides toward ion. Keeping pace with this larger the increase in accuracy and general the output. One of the aggressive irers in America in this regard is the Westinghouse Company, with plants ills and Springfield, Mass., and Meri- Particularly interesting is the East nt of this company wherein are man) nts in rifle-making machinery. of barrel-drilling machine and a new reaming machine, developed by the designs of Walter L. Clark, its ger re notable illustrations of the prog is been made. The standard type of machine is a horizontal two-spindle he new type of machine holds the barrels position and has twelve spindles, each ndividual motor. It occupies precisely space as a two-spindle machine, and one operator. This one statement the economies brought about by this Moreover, with an- independent drive for lle by an adjustable-speed motor, the h spindle can be quickly set to suit the teel which may happen to be in use. If, f a drill sticking or becoming dull, a nsuming too much power, the spindle is stopped by the action of an automatic et so that the motor stops when loaded predetermined point. s been found in practice that the vertical the barrel has marked advantages. With irrel in a vertical position, the pull of gravity rallel to the axis of the barrel, making it e to obtain a true hole and aiding to keep ear of chips. Mark a Departure from the Accepted Pra The production ncreased six-fold with: machi! Most of the details of this machine are made Vill clear in the left portion of the accompanying illus- hil ‘ tration. The barrels alone are rotated and the drill is fed into the barrel from below. The illus tration shows how the lead screw is driven. This feeds the drill chuck upward, also a traveling guide for the drill shank. The oil is supplied from oil mains in ducts in the floor from a central pump at a pressure of 800 lb. to the square inch. It enters the machine at the top, flowing through the piping system shown on the top half of the machine and is conducted by flexible pipes to the red drill chucks, flowing up through the drill shank and being discharged through a hole at the lip of the drill as in the ordinary practice for th perat From the barrel it flows down through a chute int the tank shown on the ick of the machine rhe bulk of the chips are removed direct] the tank and the oil recovered for further isual separating method In the 12-spindle reaming machine at advantages. It takes no more floor space tl the older type of machine and th compact p the spindles mak t readil handle operator. In this machine the barrels ars vung from a universal joint, producing a floating tion which enables the reamer to follow a Irate tne drilled hole. By the use of counterweights feed is obtained which automatically adjusts itself to the varying conditions always present in this operation Thus if the amount of stock to be reamed out I more than normal, the reamer slows up to meet this condition; if it encounters a hard spot in the bar rel, it feeds more slowly through this portion. The counterweights can be placed on the cross-head t give a pulling action on the reamer, or the feed can be reversed and the reamer pushed through the barrel. The vertical position of the machine makes it possible to utilize the advantageous method of feed- ing the oil through the shank of the reamer. The oil enters at the top of the machine as in the barrel- drilling machine and is led to the reamer shanks through a similar system of pipes. The barrel- nerf or Pate pe a ali Living y 1052 THE IRON AGE Novemb drilling machine has also been successfully adapted driven positively by a chain. The use of to the operation of drilling receivers. provides five rates ranging from 0.02 The machines are marketed through the Walter ‘evolution of the spindle. An adjustabl H. Foster Company, 50 Church Street, New York. splined shaft is provided and can be s carriage after each operation. As the a; along the bed and reaches the end of : strikes this adjustable collar, causing TV- “TuUrIn’S ‘ : , . : ~ Heavy-Duty Manufacturing Lathe clutch in the gearbox to be disengaged The Himoff Machine Company, 128 Mott Street, @Utomatically engages itself again wher New York, has placed a heavy-duty manufacturing ™oved to the left. : s Thea fallawi F a ; 3 lathe on the market. It was designed especially for Phe following table gives the princi; heavy duty plain, taper and form turning and is thé and specifications of the lathe: outgrowth of a machine originally designed with the Length of bed, ft.......... single idea of turning shells rapidly. All of the classes Height from floor to spindle center, . 17 1 ° . Swing over \ in of work usually handled by an ordinary lathe can be : ; Swing over slide, it machined except thread cutting, which is done by a Net welsht, Ib thread milling machine. The lathe is intended for turn Export shipping weight, ing projectiles and forgings where the finished diamete1 Contents of case, cu. ft does not exceed 9 in. A chain is used for driving the feeds. Box-section construction is used and the bed is pro- ie ; , National Founders’ Meeting Next vided with a number of box type cross ribs to serve . ¥ as reinforcement and to resist twisting strains. Two A wide variety of topics of vital V’s are provided, one to guide the head and tail stocks business men is scheduled for the annual m and the other for the carriage, the latter being large. National Founders’ Association to be held The headstock contains a large diameter, two-step cone Astor, Nov. 15 and 16. Half-hour talks ar . . - s m . . ag fol! rc far le scflayw aftar ° pulley designed for a 5-in. belt. The spindle, which 49 follows for Wednesday afternoon: : f larooa +< ter ic ¢s ctee PAraing P > 120 5 rae > B is of large diameter, is a steel forging of between 0.50 “The National Industrial Conference Bi and 0.60 per cent carbon. It is ground at bearing § alexander, West Lynn. Mass points and has a 2% in. hole extending entirely through “How Shall Manufacturers Contribute to A it. A chain oiling system is relied upon to lubricate _ trial Progress,” by E. W. Rice, Jr., president G the bearings positively, and as a check on the working Company, Schenectady, N. Y of the system sight-feed oilers are provided. A hard- “The Banker's Relation to Industry,” by F1 ip, president National City Bank, New York ened steel washer at the rear bearing takes the thrust ; oS ‘Proposal for Increasing the Effectiveness o and a nut at the rear provides an adjustment to tA ders’ Auno atin her ie Gadaeaiee Miaad up wear. The tailstock is of the extension barrel type pany. Erie. Pa. which, it is pointed out, gives clearance over the car- riage bridge for turning short work. The spindle, which is 3% in. in diameter and has a travel of 6 in., is provided with a No. 5 Morse taper. A plug binder clamps the spindle without, it is emphasized, affecting the alignment. The tailstock is fastened in position by four bolts. The convention will open at 10:30 a. m. Wednesday morning and, besides the reports of officers, the genera counsel of the association, George F. Monaghan, wi deliver an address on “Industrial Legislation”; A, F Corbin, as chairman, will make a report of the asso- clation’s committee on safety and sanitation, and J. J. Wilson, as committee chairman, will report on “Foundry Methods.” Following the morning session and a buffet luncheon, the half-hour talks mentioned for the after- noon will take place On Wednesday evening will occur the annual dir and the speakers for the banquet, at which Pres William H. Barr will preside, are Frederick P Boston, who is to speak on “Industrial Co-operat and James A. Emery, Washington, D. C., whose dress is “The Story of San Francisco.” The Thursday morning session, called for 10 a. 1 is to devote itself to an address on “Pittsburgh St Situation,” by Edward Kneeland, United Engineering & Foundry Company; “The Responsibility of the Ind vidual Employee,’ by Edward K. Nicholson, cour Bridgeport Manufacturers’ Association, and “Jo Conference Board on Apprentices,” by W. H. Van ! voort, president National Metal Trades Associat The remainder of the session will be given u} ports of committees and the election of officers The saddle is driven by a large-diameter splined shaft through a worm gear and a friction cone device forms a part of the drive and is relied upon to elimi- nate the danger of breakage through accident or neg- ligence. Steel forgings are used for all the apron gears, which are keyed to shafts having both front and rear supports. Oil tubes extending from the front of apron are employed to oil the bearing points. The sad- dle is wide and has a bearing of 32 in. on the ways. The tool slide, which is 11% in. wide, is equipped with the so-called European tool post, thus enabling two or — more tools to be held at one setting. The feeds are Pittsburgh Office for Steel Exports The American Steel Export Company, Wo Building, New York, has opened a Pittsburg! under the direction of Charles E. McKillips, Jr., } Farmers’ Bank Building. In view of the volum transactions with Pittsburgh district mills, th pany has decided to establish this service burea facilitate the handling of its orders. All purchases W! be made as heretofore through the main office in » York. Aluminum exports from Switzerland to G 1915, according to Swiss reports, were 12,000 tons. Before the war Germany obtained from Switzerland, France and Canada. The 4 The Headstock End of a Heavy-Duty Lathe Equipped with a J2dustrie A. G. is now the largest source of the Chain Drive for the Feeds and Capable of Doing Plain, Taper aluminum supply, with the largest plant at Form Turning but Not Thread Cutting Valais, at the junction of the Rhone and the \ (+é Determining Carbon in Steel by Combustion Ten Analyses Each Hour in the Labora- tory of a Large Automobile Company—De- tails of the Arrangements and the Results BY JACOB one of the largest automobile com- juired a large number of carbon and the development of a very rapid nethod. The work had to be done by tor. It is possible to obtain accurate the conditions outlined, at a speed nations per hour. In the following, ne of the chemical operation and a | account of the mechanical features is T ng conditions in the chemical labora- known rapid method of direct combus- steel and the absorption of carbon tash was chosen. The carbon train oxygen tank, purifier, furnace, puri- ‘tash bulb. The first purifying train is in order, a Johnson bulb filled with a mercury gage connected by a T rd, a tower filled with calcium chloride. is an ordinary Hoskins tube furnace quartz tube. Provision is made for he tube as it becomes clogged with wing the tube is a U tube n order granulated zinc, ride and phosphorus pent- duced and separated by The use of the chloride gthen the life of the phos- and save refilling. The s an enlarged form of ilb, made to order. The ns potash, Sp. Gr. 1.27. lf of the drying tube con- en stick KOH and the sec- P.O., introduced in small the use of glass wool. ity of this bulb is 100 to ninations and a weight in- four to five grams. The nnected and the oxygen the rate of 340 ¢c.c. per min- ted by gas meter at the end and the position of the + ted. At the end of five General Arra: bulb is disconnected and Motor inst another bulb simi- a discarded one). The apparatus dy for use. During a series of combus- gen is never turned off, saving the loss annoyance of readjustment. A half- 1.3636 gram of sample, is used, laid contained in a platinum boat. of operations and a thorough time study dividual units revealed a great loss of penditure of effort in carrying the bulb the balance and the samples to the was then absolutely eliminated by balances close to the train, or vice-versa. led from the last dryer to the balance to the bulb on the pan through the \side from the time and energy saved, perature and surface moisture condi- r changed, is absolutely parallel by the nce and can be weighed absolutely -ac- nce, W. BARBEY Che following table of operations gives the aver age time required for each unit and the routine work to be done by the operator as ascertained a test run on four different classes of ste¢ ‘ " y } W \ w i \ We From this table and the illustration the exact conditions can be realized. The fastest determina tion has been made in 5 minutes and 7 seconds. An average rate is 10 combustions per hour. The out ‘ Appar ir ‘ ny r Ray ( r put on one single 8-hr. day was 70 combustions in a running time of 7 hours and 9 minutes, the rest of the time being used for bulb filling and other work. Inasmuch as there are two three-minut rest periods every alternate two determinations, th« operator has a total rest of 25 per cent and should not be overly fatigued. Routine checks average under one point with a maximum of one and on half points of carbon, a control of 0.746 per cent a 0.745 per cent Textor standard being not unu Further study of the table may show where changes and improvements consistent with all othe factors are possible The plant of the Pacific Stee Products, Ltd., Brids port, British Columbia, which was destroyed by fire some time ago, has been lilt and placed in oper ation. Improvements and extensions are under way [The company is installing an open-hearth furnace and machinery to manufacture railroad and boat spike bolts, nuts, et 7 — <a antares Pee el ES RN eT oe le Spe ERIS (rn ee Re 1054 THE IRON AGE Novem! to form the surface a b ec de f. Upor core was then built. A cast-iron plate w tion as shown, and a sweep, the inner « conformed to the surface 0 p q r b was the exterior surface of the core. Thi prised a thin facing of loam backed vy brick as shown, and supported on a ¢ Upon completion the core was removed, the base on the line a b, and the mo then swept. The first sweep for making the basi edge c b and also the surface of the flange: sweep was used to form the flange } remainder of the mold was formed b forming to the outlinetlkjhg. Aca set immediately above the loam facing fo face f g prior to making the upper portio: Four gates were used in the mold, the locat them being about as shown in the sketch. ing two were placed diametrically oppos gates entered the mold tangentially, the the same direction through each gate, a smooth entry and rapid filling of the 1 The mold was closed by a cover plate hown in the insert sketch. The refer: this sketch correspond to the similar ref on the section of the mold in the mair illustration. The cast-iron plate, bearing pikes of varying lengths as shown i: tion, formed the basis of the cover plate. above the surface 1 m of the casting were n shorter than the distance t / on the mold, ahove the surface nm o were made somew! \ sweep of the form / m n was then used a1 between the spikes filled with loam. But a si: MOLDING CRUSHER CASTINGS was used on each of the castings, this bei { Some Large Sweep Molds at Hooven, Owens, Y a ’ Rentschler Works ae ‘ ids ' h L) The castings for one of the largest stone crushers . i ever built were recently completed by the Hooven, \ J 5 A Owens, Rentschler Company, Hamilton, Ohio, for the “CT Plate "CI Michigan Stone Company. Each of the three castings involved in the order weighed approximately 48 tons. 1 Two of the castings were the top and bottom halves of 3 Te the shell, while the third was for the spider of the . \ crusher. The largest of the three castings had a maxi- , \ mum diameter of 17 ft. 6 in., and a height of 4 ft. 9 in. a r-TA The molds for all three were swept up in loam, and cesiaaiae, . while they presented no unusual complications from the ee wt 6 foundry standpoint, their large size renders the meth- o\- 8 py ods used in molding of considerable interest. Se = a c Ordinarily castings of the character of these would . [ Y be bedded in the floor. In the present case, however, a ae steel plate curbing was erected and the molds were built a up on the floor. The spider casting requires but slight consideration, it being but a variation of ordinary fly wheel molding. The arms were formed by means of : ‘ : , ™ How the Parts of the Mold Were Mad ‘ores and the rim was swept up in the usual way. The hell castings were more difficult. The reproduction cf the photograph and Une of the on the upper flange | m. Both the mold and th drawings show the form and dimensions of one of were dried by placing in them an ordinary salama The holes in the several flanges of the casting cored. It was required that these holes be, located was first swept up, the sweep being constructed so as_ aq considerable degree of accuracy, as the holes several castings were required to match whe crusher was assembled. The holes at the « of the two diameters at right angles to eac! shell castings, and the sketch has been made to illustrate the method of molding. The base of the mold & each flange were located by means of a tem} \ i, the remaining holes between these four were th \ { by means of a jig. The brackets underneath t! \ were formed by setting wooden blocks in p \ tween the holes when the mold was being \ j the mold was dried, these blocks were dug \ a cavity of the proper shape and size in the ! \ A hard, close grain iron was used in pou \y analysis is given as follows: Silicon, 0.80 — phosphorus, 0.55 per cent; manganese, 0.: and total carbon, 3.30. The iron was drawn from two cupolas mixing runner above the mold. When 9, 1916 THE ae i rn 74 Ds 64>? Van gees eseS eeaem i een eae ee ala an eg ee. A ‘ “s/o i>e an 5 eee eee wee eee eee wees eee ee eee] af D ( ble t | WV toppers to the several gates in the mol owing the iron to enter the mold from ve 3il la and sharp taper of the cast somewhat difficult to handle. The prob y solved by the use of two cranes which gs by means of a “basket hitch.” Thi somewhat unusual. It is formed chain slings with hooks at each end ire roped around the casting as indicated itches Shop Pump Testing Plant ts turbine pumping machinery for efficiency ipacity, the Lea-Courtenay Company, New has added to its factory equipment a test pable of giving searching information of the e of its productions beyond that sufficing commercial requirements. The pump to lriven by means of a steam turbine with a er between the source of power and the imp, and a Pitot tube, weir, Venturi meter, ed nozzle or other device may be used to he quantity and head of the water pumped. nometer gives a measure of the power input np and the delivery pressure and quantity ed gives a measure of output. Thus the the pump is determined and also the ef- turbine driving the pump is a.500-hp IRON AGE , — . non-condens! ng unit built espe y speed can be regulated and held consta SUU to 5000 r.p.m. Stean irnished torpedo type boiler separat rom the the shops and designed m p! per sq. in. U s se¢ ind neidentally nata Ww ssure obtained from cold wate ss tl iynamomet« S he tors pe a haft The testing « p holding approximat measuring the l { pa ord al iS P 10-ft reury lum QO r} ompat a p \ ) I I Large Hydraulic Pt he tivd ic P j reé ‘ as 115 tor i Ch he Gor ir Tire & Rubber Co The presses, the first of whi irly date, will be ed for : f the presse ire tr ¢ a rom he hydrau i d nstalled The Monitor Controller ¢ nator of a System of automat or driven machinery, has moved 0-51 Street. The new ry Lot that formerly occupied, and extends Street from South Gay to Fredericl the old quarters has still some time t necessary to provide increased faciliti The Bal nes & of pressed-st and general ~ w Britain, } Kobert Mf eel constructon its name to the B. & offices are Conn K Mfg. now ( ompany, specialt Compar \ ited ie vlant < ‘) ire ‘ >} er rT omb Plant for Testing Pumps at Work fener erp AL ALLA LE LEME LA ES ee ie int : a Deterioration of Refractory Materia! Conditions Affecting Silica and Fire Brick in Open-Hearth Furnaces—Value of the Microscope in Fixing Quality — Bauxite and Other Brick BY H. B. during URING the last ten years, and especially tne second nali ol perio users of the best procurabie firebricks nave Irequentl on to the inefficiency of the material. This is the ipid made in both as regards output, which J directed at TI evl- dently an outcome advance me tallurgical operat means increase in the severity of g conditions, and made to WOrkKl because of the col tinually peing erials have exacting pecome made installa- efforts which ar Hence ref to cope with more and more the time it has clearer to metallurgists that efforts ought to bi economize. ractory mat been called upon requirements, and at same to decrease the great expense incurred in th ion and upkeep of furnace linings. Both in America and Great Britain, it has been customary to regard the brick manufacturer as being entirely responsible for this state of affairs. Very probably this is actually true in a great number of where the brick manufacturer with metallurgical advances and properly to un- derstand the requirements of the On the other hand, the latter has not, in cases, been in a cases has failed to keep pace consumer. many posit ion definitely to state these requirements. The first step toward supplying any particular fur- nace with a lining, etc., is to ascertain the chief destruc- tive agents at work in every part of it. If these are known, the consumer will understand exactly what kinds of bricks are most suitable for the various parts of his furnaces. It then rests with the brick manu facturer to produce the required materia It is now generally recognized that such factors as infusibility and chemical composition are not to be sole indic of the degree of refractori taken as the ness of a material, using the ‘ations broader term in its sense, as indicating the ability to resist all forms of destruc tion, and not fusion alons The old idea that high content of silica was necessarily associated with high refractoriness is also practically dispelled, and it has come to be more clearly recognized that the refractori- ness of a given material not a function of one property alone, but which working Chemical depends on a number of factors vary in relative importance according to the conditions which prevail in the place it is ised. analyses are, cours¢ ery impor tant, for, besides indicating the extent to which the material will resist destruction of a chemical naturé they supplement observations under the n scop THE USE OF THE MICROSCOP! should use of the pet Attention lying the portant quartz-rock is ‘alled to the possibilitic s under- rological microscope as an im determining whether a accessory in clay or suitable for firebricks, and also for ob- serving the changes which occur in a firebrick on burn- ing. The chemical and physical properties of a clay, or any raw material used in brick-making, are deter- mined by its mineralogical composition and texturs and if the latter could be conveniently and accurately estimated, they woul oubt constitute the 1 sci- entific basis for a ciass ficati n. The Val us by which the m neralog cal onstitutior of a clay is ascertained are particularly complex and tedious. On the other hand, practically the same results could be obtained by making use of a high-power microscope. It would, of course, be impossible to adopt the ordinary methods of cutting thin sectio1 the cas of clavs in their plastic ond o! Dut 11 nev were burnt hard and soaked in Canada balsam, there ought to be no particular difficulty in obtaining sections thir “hy CRONSHAW enough for examination. Possibly similar be obtained without burning, supposing the be warmed with the balsam and then ears It must be remembered, however, that som: stituents of clays are in such a very fins division that their detection is a matter difficulty, while in many cases it becomes possible to effect a determination with a confidence. On the other hand, quartzites, grits, and other rocks which are used in facture can easily be cut into thin sections veniently examined under the microscope. | a very good idea can be obtained of the amo quartz in the material, whether the grains sub-angular, and how they are Observations of this kind ha technical value of brick-mak angular, or in the material. bearing on the rials. In judging a particular clay as regard ability for firebricks, determination of th point is a matter of first importance. If: Mellor has classified clays and shales, first of two main groups—refractory clays which soft 1500 deg., and non-refractory clays softening b temperature. The determination of softening made under certain fixed conditions which t: account the rate at which the temperature rises. A further use for the microscope is found i appileation to the examination of firebricks, manufacturer and consumer. As in the raw materials, the mineralogical composition cat qualitatively, and to some extent quantitatively det mined, especially if supplemented by chemical anal; Apart from this, it is also possible to see how n internal fusion has taken place in burning, be in a position to form an opinion as to whet the bricks have received adequate treatment Cast respect. OPEN-HEARTH FURNACES With regard to a single furnace, the 1 materials are required to perform which depend on their particular position i nace, and furthermore, they are subjected destructive agents of both a physical and nature. It is these conditions which detern various qualities and kinds of firebricks used ing up the body, blocks, and regenerators o! ticular open-hearth furnace. Speaking in way, the arrangement of the refractory n very similar for all these furnaces. In the case of furnaces working on the a the roof, sides, and blocks are constructed bricks, while the hearth is made up of a! layers of fritted sand, resting on a stepped ment of silica bricks which constitutes the botton The sand is banked up to the le An inferior type of brick is often used The roof of an actual exampl in thickness, the sides 18 in., while the bott sisted of 6 in. of silica bricks and 15 i sand. Furnaces of this type, without slag-pock run about 16 weeks, or 144 heats, before be for serious repairs or partial rebuilding, whic! sist in the erection of a new roof and sides. If, slag-pockets are attached, which is always modern furnaces, the length of life is increas weeks, or about 198 heats. In more favorable however, the roof may last double this time The bottom lasts several years | special furnace. doors. ¢ oO! the blocks. re paired. 1056 ), 1916 g. Apparently better results are ob 1, for, according to Stoughton, an acid many 1000 heats. irnaces in the about 15 h was originally 12 in. in The years. as as irvive course of weeks thickness, is yut 4 in. bottoms are said to hav On the authority of would be considered very satisfactory practice if a furnace survived 350 heat » from 18 to 24 weeks. used time om i toy con detailed the hearth wa have for hearth. pyeen At thods one ly of basic bricks. This, however, was Another method consisted in first ram m with crushed dolomite and tar, and he whole gradually prior to subjecting In this case the The best results are obtained material is fitted on in layers in a way employed in acid furnaces. The bottom st magnesia bricks. The but are more expensive. Harbord, the hearths in th ices are built up first with a wed by magnesia bricks, and th f fritted basic material. peratures. also results sfactory. of silica and e best results, some ort course ( en tne BRICKS FOR THE BLOCKS blocks and re both the ror bricks in the same acid and forms of appear to ‘ied, but the present tendency seems to be luction in size. Very often somewhat i: ‘e used for certain parts, but it is ques ther any advantage is gained by doing so the case of modern Talbot fur magnesia bricks built As regards the regenerator ks appear to find general use for th The lifetime usually assigned to regen hed to large Talbot furnaces is the gas chambers, and 12 months in the At the end of this time thx rebuilt. tructive effects are to be traced to a variety which assist one another in their y be realized by examining the interior The surface of the roof has hol azed, gement of ery much es Various blocks hand, in 1, i? re expensive are pol ts. about chambers. has to be wort ed furnace. iy in an irregular manner, leaving oves The and walls are gl darkened. The latter have gone considerable changes in texture, tent in composition. Furthermore, por efractory sides Ss are ap- lining have cracked, or eve BODY OF THE FURNACE Examination of the interior of the body e after 14 to 18 weeks, shows that erosior has taken place, not uniformly over th but irregularly, so as to leave furrows, crevices. The most pronounced effect central portions, usually including an square situated above the middle doo) well-marked furrows spread out r port. Another example of localized de e found in the peculiar form assumed in open-hearth furnace, having its tw: ited at the upper corners. Here de st rapidly along either side of thé long hollows separated by a can be f+ ‘ fanlike two ascribed through the continuous these peculiarities best iction of fine dust the producer-gas. A swept bombard by innumerable particles of flue-dust an effective means of destructior ges.—When a body of firebrick is sub nperat variations, it generally under nding change in volume. These tempera- when eives its first heat, or when the gas is cut sual week-end tapid e ofa] ire of causes ons arise from a number changes the repairs. local character also occur whet THE IRON (a een AGE — } 105% ; oOo! ire pel 1 ed irnace ry} il ] I ses Vine { ipply pr na es I | { t Ins and diffe. ’ ' } ; } ) nemseives I ome! } ma ror ro nd sides, and ¢c1 S ‘ f} noe Cer iccess Oo lx1Ing ore $, ' i ft dust, and molte siag ‘ I e | : I mo! eT ‘ } h ¢ ert ¥ ‘ t He Dhest pendent eff { ne \A produce slight Mi ] +} ] ‘ WIth ilnings madeé ! m ria whnict temperature I nar I ier W tions, that is, p1 line the n . : posed tT tne tu piay I ne I riow } latter consideration n ‘ , j how erosion oft roots i tne ‘ r? ITnace Chey were tl aepre ny lle iT ! me } ‘ the flame TEMPERATURES Ther oncerning the temperature fferent part l furnace Le Chatelier estimates the npoerature entering the body from the re : 00 deg. ( and the air as 1000 deg. ¢ \ l l [a large iY be of obse1 il I made or ne DaSSING n regenerators into the body o 150 la the temps ire may be regarded as ry 1000 and 1200 de ( he tem] iture fl must therefore r r lerably above this, and he! the importance < f preventing t flame m n pinging on the brickworl It we 1 be interesting make direct measureme! h my ires a tained by the inner surface of if and walls, part larly the roof. . Experi mists estimate it being something like 1500 de | hi athe dangerously near the softs point of Kanolt gives 1700 to 1750 deg. C. as the yftening po of silica bricks, the determ tion h I ee! three samples \ magnesia brick, o1 he recorded as softent Y il 165 deg { Simple examination of | taker on ‘f abandoned furnace ! ifficient to vhether the tempera ‘ va hig! en i fuse the exposed faces, because the ffec ! I pletely masked bv the interference of fluxe TI ey dor often to an apprecial le extent I pres e tne form in spite of consideral pressure Microscop examination. however, makes it clear that the ; nelting pe nt of « iartz t's teiy hangs do . 1 vhich are the « come t tracted exp temperature alone Fig. 1 1 photograp! } LKe@T ron he centra | +} { ‘ Talbot furnace afte 1 we of 18 wee lengtl Va 12 in vi nna PPT luced ' tion. For convenier of des } , ; nto four portions—A, B, ¢ iD. Thet ‘ next to the ‘ pose | irface 1, } = fa oht « ré } ind hout 1 7 . The : ; ind sharply mar ff from the int: NC ee ee : ( es the port B. anou , UR h texture to A it diffe marka . oS 2% y 3% j - a SE RTP RE oF various part na exan yr the wn revealed a serie of ver) t ne cl re VW rived? ; It < r t; ; +} ; + b 7 ery part o the : ‘ OSé recr ’ wit? } object of n ing th l po ! ‘ ertain places this is not possibl ee aaa | | ; { 2 : 1058 S ( \ H H form lines of greatest weakness, so that the nar- ne re n é TI of an abandoned cl shows th In tl s, and in many p in t oof, shallow es mark the joints, and Lie su aces have a kind « embossed appearance. \ctual observation shows that far too much mortar is i ad | e extel ] no much to a ect rKny hip, 1 tt fact evel the br I emarkable variations in size and forn THE PORT-BLOCKS The brickwork in the port-blocks suffers under in fluences which are similar to those obtaining in the body f the furnace, though somewhat modified. Denudation particularly intense at the ports, and is by no means eliminated by tubes. In other parts the temperature is not so high, probably in the ieighborhood of 1100 deg. C.; although, on the other 1and, the the dust must be rendered more intense on account of its being confined in space. In any case, the surface of the bricks is fluxed, as can easily be seen by looking into the flues soon after the gas is cut off and the blocks drawn back. Fig. 2 shows a portion of a brick taken from the use of water-cooled ! action of less air flue of a large Talbot furnace. A _ section taken at the fused surface showed, when examined under the microscope, well-formed crystals of secondary quartz embedded in a yellowish glass. The of grog had converted into an isotropic which was somewhat clouded owing to the presence of fine inclusions. Another section, taken from a silica brick which had built into the block of a basic open-hearth furnace, showed the same general features, with the exception that the glass in the groundmass was crowded with skeleton crystals of magnetite. pieces been glass, been THE REGENERATORS The chief troubles in the regenerators are undoubt irom THE IRON AGE Novem): 191¢ ediy due to the slagging effects of dust of this are particularly serious. Und begin to appear very soon after the check built up. For instance, the regenerators 150-ton Talbot furnace had to be opened and general cleaning only 144% weeks aft had been erected. On this occas; surfaces of the bricks were thickly co chocolate-brown dust, which had fused with the bricks. This gave rise to iscous slag, which had run over the side ind collected into stalactites on their Thus when the regenerators are in use drip through the checkerwork from brick 1 Generally speaking, the bricks then tained their form, and were not noticeal A certain number were fractured, removed, but the majority seemed to bh: in the air-chambers there appeared to nd the evidences of destruction were n The internal structure of the bricks had any marked change. The central portions h while the outer portions were bleached, work size. ‘xtent fused, but textural changes had ery far into the interior. Within the ga ame general features obtained. In the case of a set of ypen-hearth f regenerators ot ; provided with slag fluxing process had proceeded to a very ad ‘he bricks in the air-chamber had bee hout a year, while in the gas-chamber th for a period of two years. Most of them onsiderably reduced in size. The upper su omewhat depressed in the middle, with numero reaching into the interior. In many instances of the bricks had been reduced to a partly fused and tone-like condition. Thus, unlike the case of the roof bricks, the slag which collects in the hollowed surfaces if these checker bricks gradually works its way into their interior. The gas-chambers in a large steelworks where Tal hot furnaces were being used were allowed to run for 18 months, and the air-chambers for 12 months, before heing completely rebuilt. In another instance, where basic open-hearth furnaces were in use, the gas and air chambers survived 24 and 12 months respecti while for a particular set of acid open-hearth furnaces both pairs of chambers were only allowed to run for 10 weeks. In all these examples slag-pockets were pro- vided, and ganister bricks were used in the checkers The following set of analyses throws light on the details involved in the process: irnace additional | B ( dD Per Cent | Per Cent | Per Cent | Per Ce SiO 59.80 86.34 83.62 12.70 a , ; < a 7.98 10.97 60. 71 Cal) 11.90 2.68 +.73 26.30 MeO Trace Trace 2.19 Ignition loss 0.16 0.16 1. Partial analysis of slag taken from t the furnace mentioned under B and C. B. Partial analysis of the interior of a check fter two years’ use, from the gas-chamber of Siemens furnace C. Analysis of the surface portions of the s D. Analysis of checker dust taken after 14! the gas-chamber of a large Talbot furnace E. Analysis of producer fuel ash given by Dr A consideration of analysis D makes it the dust which collects among the checkerwo rich in ferric oxide and lime, and also conta prisingly large amount of magnesia. Compa with the analysis given by Dr. Mellor, it be dent that a large portion of the oxide of practically all the lime, must come from the charged into the furnace. The small amoun! ig ncesia may be assumed to have its origin i ; ) 1916 THE IRON AGE L059 1 dolomite, which is thrown into’ the however, d t appeal repairs to the hearth are being carried tion. For example, some n r whatever its origin, materially assist ist might n of the iron and lime. lirection would produce very sfactory re alysis A) is remarkable for its re la first step ha een take m iz-pock« tent of silica. From this and othe lthou the in Oo! es eems reasonable to infer that it rep ma [ra f tl st w mes through the slag from the roof, particles of slag ir! en te pos t mi in during the periods of violent ebulli e! ‘ t ra irc port ionally occur in the slag bath, sma from the , and the prod n \ r ne pio n it ry probabdk i a vfI nly e! n ! ;ENERAL CONCLUSIONS AUXIT AND } dy first, and, in particular, the n roof, practically all the « s can be attributed to the ff ( nanges, ind he ( 10 I lus 5 é Assuming that the flame not a ctly on the roof, and that the m e proved ell carried out with bricks of unifor if { ! no reason to doubt that the ymbined veakne should nd fluxes takes by far the greatest ently high tempera ss of wear and tear, which is there the texture al | part, of a chemical nature ul f I mie I ne { vl ource of trouble is the dust, whi ture On the from the producers, and partly fron f ed ‘ ! ynnsists chiefly of oxide « ron and ) ‘ ‘ iently the roof, being built up « mestone would m 1 na n a — readily attacked, and is eats a tO eX} mel Ul Magne ! ippeal ipidly than the basic walls. As pointe prove te ' n degree of porosity does not influen ire, however, ew! el _ and ve h fluxing proceeds as much as it would ten SNrink a great dea vitl t that the ipposing the slag were allowed to accu videned pnortior t ea LW irface of the bricks. As soon as thi , ul yestiol ( t f [ gan er hed a condition of suitable fluidity tl KS ir mit n po! ty, combined with through the furnace sweeps it away maximum re tibiiity t perature fluctuatio1 ne time exposes fresh surfaces for att But so long as the ( icid nature, fluxings replenished supplies of fluxing mat v1 till go on, however de d free from crack e of volume changes probably come ne, e importance. Large cracks and genera the che " the lining can, to some extent, be ob ttention to the tie-rods, as well a 4 nm of the rate at which the furnac: Exports of Zinc Exceed Records particularly for the first heat Che Zine exports from the | ted States. while not hich develop within the bricks then is large as they were ' ' +f 1914 most cases, a source of considerabl nd early in 1915. are stil f extra i rv proportior ating the fluxing processes. Th nd exceed previous record Rased the month! Oo serious in the case of the roof. ite f 12.18? gross tons t an 14 he rf f it collect in sufficient quantity to pens ine as pigs. bars. plates and sheet he rate Indeed, the exposed surfaces are r¢ 146.184 ¢ ons pe ' ry} , bli their smoothness, and freedom from hole niled from Government dat itive exp to which abrasive action contributes al destruction is difficult to estimate, dered alung with the more obvious influ , d fluxes, its importance is not very great dditionally clear by the fact that erosi rapidly in the central portions of th« endal nfluence of abrasion is least felt. , al way out of these difficulties is ther: nd either in suppressing the dust or using The exports in Ju nd August, 1916, were 1 ve material for the roof, which would, nd 14,439 tons respectively, 1 if maintained at thi e to be basic in character. The bricks ate the total will be 178,860 tons for one year. The ex small a porosity as possible without ports in 1916 have varied between 7808 tons in March r susceptibility to temperature changes and 15,371 tons in July. The largest war month wa es to the upper part of the side walls, 17,005 tons in September, 1914, with 16,354 tons in De id and basic furnaces. mber of the same vear. tant part played by the fluxing action of inted out in the discussion on regenera trouble is chiefly chemical. Abrasive The merchant mi of the Pittsburgh Crucible Ste: nto play in only a very limited sense; Company, Midland, Pa., broke all records Oct. 26 by ther hand, the degree of porosity of the rolling 543 tons of high carbon steel rounds in 12 and their ability to withstand changes hours. During this period the sections were changed ecome important. three times. The actual rolling time was 11 hours g the possible ways which might be and 30 minutes. During this record there were tims o ire even a partial elimination of these when 199 billets were rolled in one hour and the methods suggest themselves, all of which turn was finished by making an average of 175 5/12 nsiderable practical difficulties, which, billets per hour i. t ig p < mcerant 4 a ——— Cruisers Require Larger Appropriaticons Government Must Assume Advances in Materials—French Submarine Pro- posal—Reasonable Armor Plate Bids WASHINGTON, D. C., Nov. 7, 1916.—A grave situa- BIDS FOR SCOUT CRUISERS Nos tion confronts the Navy Department as the result of Class 1—Department's design bids open