The Iron Age 1920-02-05: Vol 105 Iss 6

THE IRON AGE ESTABLISHED 1855 New York, February 5, 1920 VOL. 105: No. 6 Methods of Preparing Pulverized Coal’ Descriptions of Approved Devices for Crushing, Pulverizing,; Drying, Hand- ling, Cleaning, Weighing and Ventilating BY JOSEPH F. SHADGEN XPERIENCE has proved that the pulverization of K fuel is economical and commercially successful only when concentrated in fair-sized installations. The main function of a powdered fuel plant are a, the crushing and pulverization; b, the drying or dehydrat- ing of the fuel. Incidental are the operations solving the following problems: 1—Handling, including unloading, feeding, elevating and transporting. 2—Cleaning and checking through magnetic separators and automatic scales and recorders. 3—Ventilating for the safeguard of the health of the operator and as guaranty against dust explosions. The concentration of all these operations in one plant designed for efficient running and located with due consideration to the specific conditions and local pecu- liarities incurs an additional problem vc zy important in itself and greatly discussed lately. Since powdered coal was born commercially in the cement plants, the first installations were strongly in- fluenced by the experience in that industry. The data given by the pulverization of shales and limestones were simply transposed and the same machines in- stalled. The problem of distributing the coal powder hardly existed because the kilns were located close to the crushing plant and the number of burners was limited. The Lebanon installation with its varied metallurg: cal applications-—open-hearth and pit furnaces, forge fires and heating furnaces—gave a great impetus to the new industry and caused the manufacturers to evolve independently. Since 1912 the powdered coal plants have presented distinctive features as to the machinery installed, and the considerable efforts, focused on the distribution of coal powder, produced very satisfactory solutions. The efficiency of the pulverizing plant will be the heart of the whole question; the whole future of this art of burning solid fuels will depend on its eco- nomic operation. Improvements will only broaden the fields of application. Crushing and Pulverizing The science of crushing and grinding forms the foundation of many basic industries like mining, ore ‘ressing, manufacture of cement, etc. Hand, hammer ind iron stones have long given way to special machines developed for mechanical drive and continuous opera- tion. The importance of the problem is clearly shown “Copyright, 1920, by Joseph F. Shadgen. The author is engineer now engaged in rolling mill work in the United tes. and wrote “Status of the Powdered Fuel Problem” THE Tron Ace of Jan. 1. by the painstaking and thorough investigations on the subject, published in all languages of which the classic books of R. H. Richards are the most complete and the most interesting. The experience of the whole crusf#.g and grinding industry for minerals of all kinds has taught: That the grinding of any material has to be done stepwise to be efficient and economical; that the choice of the machine best suited for each step depends on the hard- ness of the material to be crushed or pulverized. By grinding, the cohesive forces of the material are brutally smashed and the solid is split up into smaller lumps; in non-fibrous mineral the hardness usually expresses the value of these binding forces that have to be overcome. Hard, gritty stones like trap rock are more difficult to crush than soft material like lime- stone, whose molecular attractions are weaker. Coal is a mineral, heterogeneous compound, com- posed mainly of carbon mixed with impurities such as shales, pyrites, silicates, ete. These foreign matters that produce the ashes on the grates are harder than the combustible matter. Consequently, all crushers and pulverizers have to exert pressure high enough to annihilate the cohesion of both carbon and impurities, and have to be built to resist the greater wearing action of these mineral impurities, particularly in the case of centrifugal pulverizers. The particular structure of the coal veins and cleav- age texture of most mineral fuels simplifies the mining and makes it possible to deliver, without great diffi- culties at the head of any pit, so-called “run of mine” coal, a mixture of big and small lumps of all sizes and forms with dust and powder. A large amount of coal is sold in that form. If it contains too many impurities it may be profitable to size, or wash, or clean it ac- cording to the habits of the trade, prescriptions of the user, or economies of transportation. Preliminary Crushing The first step is crushing to uniform size, done very efficiently by three kinds of machines, one of which is the roll crusher. These machines consist of a sturdy frame with one, two or four rolls turning at low speed; the rolls may be plain, grooved or toothed cylinders of various diameters and lengths to suit the output. They are made by a score of manufacturers in more or less perfected constructions, and deliver coal in uniform sizes from 1 in. to 1% in. lumps, down to buckwheat or barley, according to the number of the rolls. The coal drops from the feeder between the rolls, which turn in opposite directions, and is crushed by the direct 389 390 pressure of the rolls, which pressure is regulated by springs acting against the bearings of the rolls. The operation is continuous because the coal is drawn into the machine by the rotation of the rolls and drops by gravity into the delivery chute. This preliminary crushing is very inexpensive, the machines are cheap, the wear of the rolls is practically negligible, the power consumed is small and the capacity of production is enormous even for the smaller sizes. An adequate feeding device ought to guarantee a positive flow of coal, to reduce the idle running, and the foundations ought to be solid to avoid vibrations and shocks. A second type is the hammer crusher. These ma- chines are sometimes used for preliminary crushing and can be fed by any run of mine having lumps of 4 in. and less. They deliver the product in a finer state, sometimes 80 to 90 per cent, through a 20-mesh screen. These machines imitate the action of the hammer, where the impact of the blow, and not the pressure, smashes the material, tearing apart the cohesive forces. Hammer crushers are usually formed by an anvil- plate, a series of hammers mounted on the spider of a shaft turning at high speed, a grid screen regulating the size of the output, and a feeding device. As a crusher for coal and material not too high in silica these machines are extremely efficient, if designed cor- rectly according to the principles of the impact hammer blow. Unfortunately, constructive difficulties have handicapped many machines on the market and the type is not popular. In fact very few makers have recog- nized the real value of the high speed of the hammers and the importance of their weight in spite of the well- known mechanical law that the impact effect grows with the square of the velocity and is in direct propor- tion to the mass of the hammer. The fantastic so- called “X-ray” pictures and advertising sketches, cir- culated by the trade, prove the better selling imagina- tion, but also the low engineering level of makers and give a very poor testimonial about the scientific knowl- edge of the buyer. Ball mills are the third kind of machines used for preliminary crushing. Their action is based on the con- stant rubbing, pounding and dropping of the coal] lumps against themselves and against steel balls, of sizes varying from 3 in. to 6 in. in diameter within a steel- plate drum, lined with segments of any material re- sisting wear and tear. Ball mills are slow rotating ma- chines (20 to 35 r.p.m.), of great weight and provided with suitable feeders and discharge spouts. They grind any material from 3 in. to 2 in. lumps down to a mix- ture passing through the 20-mesh sieve. The diameters of the drum barrel vary from 4 to 8 ft., according to the capacity, and their lengths range from 3 to 7 ft., according to the nature of the mineral to be crushed. These ball mills are very suitable for hard ores and rock such as silica stones, trap rock and porphyry minerals, and they have given best results for coal of all kinds. Their low speed makes the operation very reliable and their service very sure and foolproof. Most of the makes on the market are equivalent and present practically no differences in design. The only factor of real importance seems to be the weight of the charge of balls. Final Pulverization The main operation in a powdered fuel plant is the final pulverization of the combustible, the production of a fine impalpable powder and dust of a constantly uni- form degree of fineness. The machines used have not only to pulverize but also to guarantee a constant uni- form grind which requires an automatic sifting. Two types of mills on different principles only solve these combined questions. They are tube mills and cen- trifugal mills. The pulverization of the tube mills is due to the THE IRON AGE February 5, 1920 crushing action of flint pebbles or steel balls (% ir to 1% in. diameter) which are caused to rise by th. centrifugal force of the rotation of a lined steel cylir der. By choosing the speed judiciously the centrifuga force will not overcome the weight completely so tha the mass of pebbles and material lifted to a certai: height will drop on the part remaining on the botton of the drum, thus pounding, grinding and polishin, every particle to dust. Fed in at one end of the drun the material travels through the tube, generally 1 to 25 ft. long, by the law of deplacement and drops ou: at the other end. The degree of fineness is guaranteed by an end plate, slotted in a way that retains th coarser material, and by regulating the feed, becaus: the longer the material stays in the tube the finer it will be ground. The factor that influences most th: efficiency of the machine seems to be the weight of th. charge of balls, which explains the pressing of the flint pebbles (density less than 3) and the general adoption of steel on chilled balls (density about 7.5). In late years the closely related ball mills have bee: combined with the tube mills into one unit, with dis- tinctive patented features. These combinations save the double handling of the material with the inter mediate elevators, bins and feeders, and receive mate rial from 2 in. to 3 in. down at one end and deliver at the other end the finished product ground to the required degree of fineness. These combination mills have found a ready market and are very efficient and practically control, both in Europe and in America, the artificial Portland cement field with its extensive grind ing and pulverizing of raw material, coal and clinkers. The simplicity of construction, their low running speed, their small repair bills and the possibility of building large units are the appreciated advantages, which out- weigh the somewhat high power bill per ton pulverized and assure low ultimate cost of grinding. Centrifugal Mills The centrifugal mills imitate the burring action of the chemist. A rotating steel mass is pressed against a hard steel ring and by constantly throwing material between these parts the crushing action is obtained. The pressure is generated by the centrifugal force of a shaft rotating at high speed driving the rolls or balls These mills are not suited for hard, gritty material be- cause they do not resist the abrasive action of highly silicated rocks, but they give very efficient service for the pulverization of softer materials like soft lime- stones, phosphate rocks, coal, coke, etc. They are the favorite fine grinder in the powder coal plants to-day and reduce any solid fuel from about 1 in. lumps down to an impalpable dust. Their productivity is neverthe- less considerably increased by the previous reduction to % in. and % in. size, or less. The above principle has been developed by the manufacturers along different lines with varied success. Some designers preferred a stationary horizontal ball- ring with swinging horizontal rolls; others loose stee! balls, while other makers thought a vertical ballring with vertical rollers would give better results; others even made the ring turn, too. The prototype of these mills, as far as the author could trace priority, are the well known, now discarded, “Huntington Wet Pans” described in all mining treatises. The pulverizing action depends entirely on the rota- tion and pressure of the rolls, roller or balls against the grinding ring and the effectiveness of the device assuring a constant uniform stream of material be- tween these crushing masses. That production in- creases with the number of grinding balls or rolls seems evident, but practical consideration and simplicity of construction limit their multiplicity. To assure easy balance an even number of balls or rolls seems logical on account of the natural reactions in diametrically February 5, 1920 site directions. The velocity influences the output , in quality and quantity, but an increase of speed nd certain limits is not warranted for mechanical ons and safe operations. [he diameter of the ball ring is of great importance | should not fall below a certain dimension so as to d any appreciable wear and tear, not only because replacement is a rather tedious erecting operation the field, but because it seems that an increase of original diameter due to wear reduces the efficiency the crushing action. This explains why the smaller hines do not realize the same results as the larger pes, a fact openly acknowledged by a leading manu- icturer. As the centrifugal force depends on the weight of rotating masses and the radius of rotation, the ressure exerted can only be partly regulated by some achines. This pressure ought to be determined with ire, since the harder mineral impurities have to be rushed as well. Only thorough theoretical calculations ind careful practical tests can decide upon the exact relation between these different variables. Standardiz- ition has been in this problem a great handicap to progress, because the same machines are not only un- hanged for years, but are recommended without change for material of different hardness. The importance f the feeding devices has been entirely overlooked. The centrifugal mills are usually provided with one feeder, of the screw, roll or plunger type, and all atten- tion has been concentrated on this visible device regu- lating the continuous flow of material to the machine, but these apparatus do not feed the rolls, they do not guarantee that each roll or ball receives its continuous stream of material. Some types of mills provide for this by special plows, or ingeniously curved blades throwing always enough coal between the rolls and the ring where the real grinding is done. The rolls or balls themselves ought not to plow through the material accumulated at the bottom of the machine, because their function is to grind in the one lirection determined by the action of the centrifugal force. Constant rotation through the layer of material it only causes inefficient working conditions, but also reates additional wasteful friction; greater wear and 1 higher power consumption. In fact, ample room should be provided between the floor from which the naterial is picked up by the plows and the ring die ) insure a free motion of the crushing masses without iragging in the mass. This consideration explains why ertical ring machines deliver much less fine powder, ive a smaller output and necessitate the installation f bigger motors in spite of the simplicity of their con- struction, their higher speeds of rotation and their pparent direct action. Screening and Sifting The absolute necessity of delivering an impalpable vder characterized by a definite degree of fineness juires an automatic sifting device with every mill. While for separation of coarse materials only mechani- . grading methods are available, for very fine pow- ‘ers mechanical and pneumatic principles are used for parating purposes. Mechanical sifters consist essen- ily of perforated or slotted plates, woven wire screens r special bolting cloth. The ground powder is thrown r against these sieves, what passes through the nings is fine enough, while the refused coarser par- s are retained ‘and returned for a second grinding. In centrifugal mills the screen is usually mounted e the ball ring in two circles. The powder pro- ed is lifted by the action of rudimentary blades rming and whirling the dust-laden air against the The refuse drops back into the mill and the r powder passing the slots or mesh openings is cuated to the bins. THE IRON AGE 391 Mechanical screening is by no means perfect. It de- pends entirely on the effectiveness of the sieves, diffi- cult to inspect and troublesome to replace. The main objection is the unreliability, because the abrasive ac- tion widens the mesh openings and a weak spot in the sieve causes an abnormal local wear and spoils the whole effect. On the other hand mechanical separating is very cheap, requires very little power and gives satisfactory results for powder not too hard and not too fine. Pneumatic sifters are more perfect in their opera- tion, more reliable and constant in the fineness of their grading, more effective within a large range of fine- ness, and especially adapted for the finest impalpable powders, but they necessitate in their present market form the costly installation of a special fan with motor and consume a great amount of current for their opera- tion. The actual tendency toward greater fineness of pow- dered solid fuel has increased the popularity of the pneumatic separators. The users seem to prefer to pay in kilowatts for the reliability of operation and for the absence of bother with cloth and screen. Inci- dental advantages of importance are absolute dust- proof installations and delivery of the coal powder at any convenient height and distance from the mill; pneu- matic sifters furthermore increase the output of the pulverizers by immediately removing the fine powder and by keeping the mills cleaner and cooler by constant air circulation. In its actual form air separators consist of a grad- ing device just above the mill, separating the coarse from the fine, a motor-driven fan, a cyclone separating impalpable powder from the air and connecting air lines with return lines. The principle involved is the floatation of dust in air currents; important factors are the volume, velocity and pressure, positive or nega- tive, of the air stream in the various phases of the circuit. To improve the efficiency of air separators seems to be a very promising field for inventors, because their power consumption is entirely out of proportion to the real useful work they perform. For instance, a centrifugal mill, pulverizing 5 tons of coal per hour, requires a 25-hp. motor to drive the fan. Through theoretical investigations and detailed analyses of the whole system the author has been convinced that great economies are possible with slight changes, because on some machines the flow of air is contrary to all laws of physics in spite of well patented features and clever talking points. A reduction of the operating cost of air separators will not only extend the market of pow- dered solid fuels through cheapening the cost of pro- duction, but will also prove beneficial to a score of other industries where fine pulverization is essential. Drying and Dehydrating The moisture content of solid fuels varies consider- ably with the nature of its carbon and the age of its formation. As the problem of drying is closely re- lated to the amount of water that has to be evaporated, the methods of dehydrating vary from coals and an- thracites to lignites and peats. According to the “Mechanical Engineers Handbook” over 75 per cent of all kinds of American coals and anthracites record less than 10 per cent moisture, so that the statement that most of the coals or anthracites coming fresh from the mines contain from 2 to 8 per cent water can be accepted as a fair average. If exposed to rain or washed for cleaning purposes or grading, slightly over 10 per cent water will be ab- sorbed, of which 4 to 5 per cent will again disappear through dripping or evaporation when exposed to the air. Lignites, and especially peat, have very different characteristics; their carbon is much less dense, their 6. & ae ae seer r Seems elie setlneponey i, CS creaae se 392 origin more recent, their mineralization much less ad- vanced and their texture more vegetal. Lignites or brown coals record from 20 to 25 per cent of moisture fresh from the mine, and after a lengthy exposure to the air they show around 12 per cent, while fresh samples of peat direct from the ditches contain over 75 per cent of water, which is reduced to 15 or 20 per cent and even less according to the age of the forma- tion and locality. Mechanical reasons pertaining to the economies of pulverization explain the necessity of dehydrating the fuels to be ground. It must be conceded that this pre- scription is not absolute and that tests may be made successfully with powder that is not dry. But to assure a continuous service without shutdown periods or an- noying disturbances it is very prudent to accept the value of the prescription that less than 1 per cent of water ought to be found in the fuel powder. Because the coals and anthracites do not stick to steel plates, they are usually dried in drum dryers, composed of slightly-inclined, rotating steel cylinders. According to the fancies of the manufacturers they are built with one drum, or two drums, one inside of the other. A-grate usually permits the production of the hot air that evaporates the moisture, and a motor- driven fan or stack guarantees the evacuation of the waste gases. Of importance are the inclination of the drum and its velocity of rotation, the exposed surface (diameter and length of shells) and the time of expo- sure given by the feeding device. All these factors have to be valued carefully as to their relative in- fluences. The great advantage of the drum dryers consists in their automatic way of handling and transporting the material to be dried. The combination of the inclina- tion and rotation assures an easily controllable advance of the material. Drum dryers practically control the powdered coal market in their more or less perfected forms. Dehydration is a specifically low temperature opera- tion. The fuel needs only to be treated slightly over 212 deg. ‘Fahrenheit, where evaporation takes place at atmospheric pressure, and care should be taken so that under no conditions the temperature raises above 350 deg. or 400 deg. Fahr. This for two reasons: first, be- cause it is absolutely unnecessary and wasteful as no increase in efficiency is obtainable by higher tempera- tures; second, because it is dangerous, as some coals, containing volatile hydrocarbons, may become distilled, causing ignition of the fuel and destroying, or at least injuring, the whole installation. Waste gases from high temperature producers, like boilers or reheating furnaces, are often by-passed and utilized with great dehydrating, dis- pensing with the cost of fuel required for that opera- tion. advantage in Accessory Operations Coal transportation is usually accomplished in bot- tom-door cars of great capacity easily unloaded into track hoppers of the usual kinds; the unloading tracks are either on floor level or elevated on a trestle, ac- cording to the peculiarities of the local conditions. Sufficient storage room ought to be foreseen for the coal, preferably in the raw form, uncrushed and un- dried, to prevent shutdown. If possible, a week’s supply ought to be on hand outside of the pulverizing plant proper at easy reach, while in the plant a minimum of two days supply ought to be stored in all hoppers, bunkers and bins. Lump coal is elevated very economically by bucket elevator of the chain or belt types. The hoisting equip- ment ought to be totally enclosed in sheet iron frames to prevent accidents and to reduce the formation of dust. Belt conveyors or screw conveyors are admirably THE IRON AGE February 5, 19°) suited for horizontal transportation of coal. The bx can even be inclined, if local conditions require it, to 15 deg. Screw conveyors ought to be covered a; airtight to avoid production of dust. To insure the machinery from breakage and to cover tramp iron that may be accidentally mixed with the coal it is very recommendable to install ma; netic separators. Most popular is the magnetic hx pulley type of standard construction. To guarant« good action the coal layer passing over the pulley ough: to be spread out nicely, not over 2 in. to 3 in. thir in order to give the magnetic field a chance to ac: properly. Control instruments in forms of automatic scales, jf possible of the recording type, ought to be installed, to permit an easy check of the running of the plant and the amounts of coal handled. All foundations in the pulverizing room ought to be above floor to avoid any accumulation of coal dust and to prevent accidents This precaution ought never be neglected. Proper ven tilation of the building is a matter of course, but al! the various apparatus ought to be ventilated, too, es- pecially the dry coal elevator, as well as the dry coal bins, to avoid the “sweating” of the coal. Sequence of Operation and Choice of Machines The drying of coals and anthracites usually follows the preliminary crushing to proper size, this for the good reason of reducing the formation of dust to a minimum. Furthermore, as most of the water in the coals is not chemically combined with the carbon, no better results are possible by dehydrating coals in a more finely crushed form. If ball and tube mills are used for first pulverization it is most recommendable to stop the preliminary crush- ing at 1% in. to 2 in. lump size, but if centrifugal ma- chines are used preliminary crushing ought to deliver % in. to 1 in. lumps and less, because the biting angle between rollers or balls and ring die limits the upper size. It seems even that, in case of large installations grinding 300 to 400 tons daily, it would be profitable to crush first down to 2 in. in roll crushers, to dry, to disintegrate in a hammer mill with large screen down to % in. and less and to pulverize in centrifugal mills. This would divide the grinding into three steps. The installation of the hammer crusher would considerably increase the capacity of the pulverizers and reduce the number of their units. A noticeable drop in the power consumption per ton of coal ground seems to be as- sured by any large installation developed along these lines. On the total cost of pulverization hinges the econ- omy of this method of burning solid fuels. The effi- ciencies obtained through more perfect combustion and better control have to outweigh the operating cost of the pulverizing plant, including overhead charges, to guaranty permanent success. Published data on this subject are very incomplete and lots of information is obsolete and misleading on account of the ever-chang- ing economic condition of the present period. {t is generally conceded that the cost of pulveriza- tion per net ton of coal varies from 25 to 60 cents. This is far from precise and leaves a liberal margin for local variation. The factor that influences most the cost of operation is the size of the pulverizing plant. A large daily capacity reduces considerably all incidental charges and permits the full development of up-to-date handling methods and takes full advan- tage of concentration. Small plants have often to compromise on the choice of machines, a condition that reduces efficiency. The recognition of this fact brings very near the suggestion of creating large plants through co-operation between local users to combine their individual plants into large installations for mutual profit. Fittings and Flanges of Cast Steel Casting These in Green Sand and a New Shop to Machine Them Features of New Department of Reading Steel Casting Co. BY EDWIN F. CONE completely machined, the Reading Steel Cast- ing Co., Reading, Pa., has erected a shop at a ost of $250,000. While equipped to machine the arious castings produced, the shop is also equipped for finishing its product in the special line which it has lately entered. This new field is that of fit- tings and flanges of cast steel. The new building was erected during the past ear and is of fireproof construction with steel frame work, gypsum roof and concrete plastered sides. It is lighted with continuous steel sash. The length is 200 ft. and width 110 ft. with a \5-ton runway in the center, 50 ft. wide, with two parallel bays 30 ft. wide. Provision is made on oth sides for a gallery for small tools. On one gallery is located modern wash rooms, lavatories and lockers as well as a small separate machine or repair shop for the general foundry. Only such tools as could handle steel castings at very high speed were selected, in addition to some special machinery not heretofore on the market for finish- ing steel flanges and fittings. The equipment in- ‘ludes four Bullard vertical boring mills, one 100-in. .Niles-Bement-Pond boring mill; seven lathes; six radial drill presses, ete. There is, of course, tool room equipment for the manufacture of tools and Besides the output of the standard ells, tees and rosses, the company has produced and is prepared » make all of the large special fittings such as elbows, tees, crosses with side outlets, ells with side utlets, Y’s, laterals, etc. The illustrations show me of these shapes already produced. Probably the most interesting feature in con- jy meet the demand to secure steel castings nection with this special work is the molding prac- tice employed. A method has been perfected which permits the casting of fittings and flanges in molds which have not been baked or dried in any way, the castings machining without blow-holes and standing without leakage from 500 to 2500 lb. hydrostatic pressure to the square inch. Heretofore it has been the practice in steel foun- dries to make castings of this kind only in dry sand molds. It was also found that solid castings could be obtained only by the use of extreme care. In fact, the difficulties surrounding the production of material of this kind were so great that the ma- jority of the foundries were disinclined to accept such orders. It is therefore a surprise to most foundrymen that such work can be made success- fully in molds which have not been baked. Broadly speaking, the secret of the success is two fold. First, the sand mixture which is special in every way and largely a secret. Second, unusual means as well as great care in venting the molds and cores. The sand mixture used impresses the newcomer into the foundry as akin to a gray iron sand mixture because it is almost black in color, but its binding and other qualities are exceptional. Another feature is that with the exception of a few very special shapes, all castings are produced on molding machines. This results not only in a saving of labor but also in pattern equipment, it being possible to mold from two half patterns on a match board two pipes, whereas by the other process of hand molding only one pipe is possible from one whole pattern and in much less time. One of the features of the foundry practice is the success achieved in eliminating the necessity for labor. e of the Cast Steel Fittings and Flanges Machined in the New Machine Shop of the Reading Steel Casting Co. 393 ao Mer toma The Department of the Foundry Where Large Furnaces at the Left The The handling of much of the material by common labor has been replaced by the use of tumbling barrels, grab buckets and lifting magnets. Not so long ago in this foundry and in many plants to-day all castings, after they are removed from the sand, are cleaned by pneumatic hammers or hand hammer cleaning. The present practice at the Reading foundry is to place nearly all castings directly into tumblers where sand, nails and excess material are quickly removed and from which the castings emerge unusually clean and polished. The company has nine such tumblers, two of which are also supplied with a sand blast which operates at the same time the castings are being tumbled. One of the largest of such machines ever constructed is shown in one of the illustrations. It was made by the company itself. The outside dimensions are 7 ft. long by 3 ft. 6 in. in diameter, the cast steel plate forming the shell being about 11% in, thick. It is calculated that unusually large castings can be tumbled in this and cleaned much quicker than by the usual process. THE IRON AGE February 5, 1 Castings Are Made in Green Sand and Poured Directly from the Open-H Reading company claims that by this method certain heavy castings have been produce: few hours as compared with as many days in dry sand Another factor in eliminating labor has been t} introduction on a considerable scale of mold machines. The company now has in operation o 40 such machines. By their use it has also be: found possible to make some unusually large o1 least long castings which some years ago were not attempted except by hand molding. The uss snap molds, especially applied to even sizeable cast ings, has been widely extended until this practic a special phase of this foundry’s output. One of the illustrations shows a department of the plant where green sand molding is being suc cessfully applied to large general jobbing castings The same sand mixtures are being used here that have been described in connection with the pipes and fittings. Here struts for ships are being made, part of the pattern being embedded in the foundry floor. In the IRON AGE of Sept. 23, 1915, the plant of the Reading Steel Casting Co. was fully described as it then existed. At that time it was rated as the largest converter steel foundry in the country, In the Left Foreground Is What Is Believed to Be the Largest Tumbler for Castings in Use. Cleaning casting by tumbling is a feature at this plant, nine being in use. February 5, 1920 necializing of course on small castings. With the e of four converters and two cupolas the output as 600 tons of finished castings per month, aver- ging 30 Ib. each. Since then some radical changes have been made, esides the ones already described. About two ears ago the company supplemented its melting juipment by installing a 10-ton acid open-hearth irnace. A few months before the armistice was igned, another open-hearth furnace of 20-ton capac- vy was built for producing shell ingots of cast steel. rhis was located in a new extension to the main foundry building at the extreme western end of the main building. With the resumption of more normal times the new 20-ton furnace has been turned on to regular ders for the larger sized castings as well as assist- ing in the pouring of small castings also. The former 10-ton open-hearth furnace has been dis- mantled and is now being rebuilt as a 20-ton fur- nace adjacent to the new 20-ton furnace. Welding Steam Manifolds Steps in the manufacture of high-pressure steam manifolds in the shops of a Pennsylvania engineering company by the Airco process are shown in the accom- panying illustrations. This construction is explained as providing not only an.easy method of manufacture, but as resulting in a construction of great strength and preSsure withstanding qualities. In welding one of these branches a piece of 4-in. steel pipe 18 in. long is used. The centers for the THE IRON AGE 395 The company therefore is a producer of both converter and acid open-hearth castings. As in- dicative of the expansion of the company’s business in four years it may be stated that the present out- put or capacity is close to 2000 tons per month of finished converter and open-hearth castings, small sizes predominating. Arrangements are such that it is possible to pour either open-hearth or converter metal into either dry or green sand molds. Most of the converter metal however is now applied to the green sand and snap mold smaller castings. The combination in the same foundry of both the converter and open-hearth metal, as operated at Reading, makes possible as large an output as some foundries are to-day securing from three 25-ton open-hearth foundries. An important factor in this larger comparative output is the use of labor saving equipment such as molding machines, rumblers, etc., as well as the extended adoption of green sand molding. cost was about $200. The dealer who supplied the coffee took charge of operations and sent an expert who instructed the woman, who now attends to the work, in the intricacies of proper coffee making. Each department foreman has his pots or carriers which hold enough to supply all men in his department. Each morning the foreman ascertains how many of his men want coffee. This memorandum he sends to the woman who has charge of the kitchen, and comes on the job at 9 a. m. About 15 min. before the noon whistles blow, foremen send to the coffee kitchen, which sleeves are chalked off and holes cut by a cutting torch. Then the first socket is lined up and welded, others following until the job is completed. Nipples are placed in the sockets in order to protect the threads during welding. Foliowing the welding of the sockets, disks of the proper thickness are cut and welded in each end of the manifold. These disks are chamfered, so that when placed in position in the manifold the necessary bevel or V for a strong weld is secured. To weld a manifold complete takes about two hours and requires approximately 80 cu. ft. of oxygen and 70 cu. ft. of acetylene. The apparatus and gases were supplied by the Air Reduction Sales Co., 120 Broad- way, New York. Coffee an Offset to Production Fatigue A coffee kitchen, from which the beverage is served at noontime without charge to all its employees, has proved a valuable aid to efficient manufacturing at the plant of the W. S. Tyler Co., Superior Avenue and lhirty-sixth Street, Cleveland. One of its principal products is wire cloth and screening for straining paper pulp, etc., and this refreshment at a time when ‘he mental and physical faculties of the workers begin decline has been found by the management to stimu- > the digestive organs enough to keep a man fit roughout the day. The kitchen began operations on Dec. 2, 1918. oree 35-gal. percolators were installed. The initial is a little glassed-off corner in one of the workshops, for their supply. The pots and pails, each bearing a metal tag with the foreman’s name or department, are ready for distribution. Each man who wishes to take advantage of the coffee service is required to buy his own cup, pint-size, white enamelware, at 25 cents. When the service is discontinued or the man quits the employ his 25 cents is refunded. About 500 employees take advantage of this service. Each man gets nearly a pint or the equivalent of two large breakfast cups. The total cost figures about $20 a day, that is four cents per man or two cents per cup. This high average is due to two causes: The company buys the very best coffee it can get and serves it with a liberal allowance of pure cream. The daily use of cream amounts to six gal. This is included in the total daily expense of $20, as are also the wages of the woman who makes and serves the coffee—$2 a day. The company uses on the average 22 Ib. of coffee a day. Emphasis is placed by E. P. Disbro, assistant treas- urer of the company, on the importance of maintaining high quality of beverage. In his opinion “it is just as foolish to supply men with poor coffee as it would be to buy a poor grade of oil for a very delicate machine, and any manufacturer will agree that that is a poor saving.” The Nukol Fuel Co., 88 Bay Street, Toronto, Ont., plans to erect briquetting plant in Port Arthur or Fort William, Ont., at a cost of $100,000. ese ee etme rie Bs Bang oo i ae ai " - a ~ oe ~ te een Salhtielttity. 6RE te Slee te 396 New Avey Automatic Drilling Machine An Avey drilling machine which can be used as an automatic, semi-automatic, or plain hand feed drill is being manufactured by the Cincinnati Pulley Machinery Co., Cincinnati. Conversion from one style of opera- tion to the other is quickly made by the movement of one member. When used automatically both approach and return of spindle are automatic; the spindle going through a continuous number of cycles of operation without the necessity of engaging or disengaging the feed by the operator. In the semi-automatic feeding, the spindle completes one cycle, consisting of engaging the feed by a clutch lever by hand, feeding down to depth as determined by the graduated depth stop, tripping auto- matically, returning to the starting position and stop- ping. The change from full to semi-automatic feeding is obtained by giving the adjustable pin a quarter turn so that in this way the power feed is engaged or not when the spindle returns. The hand feed lever, used only when the power feed is. disen- gaged, has a rat- chet arrangement whereby it can be set in any po- sition in relation to the spindle or can be disengaged without revolving when automatic feeding is util- ized. The spindle can be advanced by hand ahead of the power feed without disengag- ing the latter and without loss of time, as_ the clutches pick up the power feed automat ically where the hand Quick Conversion from | Automatic. to feed drops it. Oectatam ix Mika sar a ee This is accom- of This Avey Drilling Machine plished by means of an extension weight bar directly in front of the operator. The design and operation of the clutch are explained as making it possible to drill blind holes within 0.002 in. The strokes can be varied in length from a maxi- mum of 5 in. to a minimum of % in. The greatest number of strokes per minute is 30, and 4 feeds and 4 spindle feeds are available. The capacity for drilling is % in. in cast iron and % in. in steel, with maximum spindle speed of 3500 r.p.m. All revolving members in the head, as well as the idlers, spindle and counter- shaft, are mounted on annular ball bearings. Several attachments can be added to the machine, including an automatic cut-off valve for the lubricant whereby the latter flows only while the drill is cutting, and a stroke- limiting device which automatically controls the num- ber of strokes the spindle will make before stopping. Opposed to the Metric System The committee on trade and commerce of the Cham- ber of Commerce of Pittsburgh has given careful atten- tion to the question of the adoption of the metric system of weights and measures, and has reported in opposition to it, saying in part: ; The metric system was legalized in 1866 by virtue of an Thus, for over 50 years it has stood on a legal parity with the English system and fully available to all who wished to use it. Is it not, therefore, fair to say that if it cannot win on its own merits by voluntary adop- tion under the protection of this law it is not entitled to win act of Congress. THE IRON AGE February 5, 192 under a law of force? The present attempt is to proh the use of the existing system and make the metric sta ard the one exclusive official system. At this time, when as a result of the world war, prod tion and commerce are in a chaotic condition and when whole world is hungry for the products of the two grea nations whose commerce would bear the whole burden of inopportune tampering with the fundamentals, it would folly to make “confusion worse confounded” by attempti an'y such radical change. It is and always has been the practice of Pittsbu manufacturers to quote upon inquiries as well as to exe orders based on the metric system. This is readily done converting into our own equivalents. Three-fourths of the world’s manufactured goods more than a large majority of the machine tools used Latin America are produced on the system of measurem which we use to-day. As soon as it became known that the chamber wa consider this subject, your committee began to receive rapid succession communications from prominent manuf turers and representative organizations, all but two of wl vigorously condemned the effort to further disrupt our lustrial and commercial conditions by inopportune tam, ing with such a vital basis of production. Only two firms appeared to favor the meter-liter-gr system and one of these qualifies its opinion by stat ‘unless the changing over would have an effect that we Q” not know ¢ Turntable Tractor A tractor made for turntables of any pit rail radius is announced by the Whiting Foundry Equipment C Harvey, Ill. The main frame is V shaped, consisti: of I-beams and channels rigidly connected and attached to the turntable by steel hinges, so as to prevent vert cal movement of the tractor when the engine is run on and off the table. The frame is extended outside the traction wheel so that counterweight may be supplied to obtain additional tractive effort required for heavy conditions. Traction is obtained entirely by gravity and not by springs. The gearing can be readily re- moved without disturbing adjacent parts. The sanding device consists of a steel sandbox with a vertical swinging valve connected with a sand agi- tator. Valve and agitator are operated from within the cab. The sandbox is located directly underneath the cab floor and is filled or cleaned from within. The brake is an asbestos-lined band type of the same design as supplied on the company’s electric trav- eling cranes. It is explained as powerful enough to This Turntable Tractor Is Obtained En tirely by Gravity Traction in stop the table suddenly or to give the operator a deli- cate control for registering rails. The tractor is propelled by a motor located on top of the structural frame, high enough so as not to be affected by water in a poorly drained pit. It is 4 variable-speed, reversible, heavy type motor of standard design. The controller is a standard, reversible drum type. The tractor is wired complete and ready for connection to power leads. Phosphorus and Sulphur in Steel Plans for the Comprehensive Investigation by a Joint Com- mittee of Three Organizations pointed at the initiative of the American So- ciety for Testing Materials, the Railroad Admin- tration and the United States Bureau of Standards, the investigation of the effect of phosphorus and ilphur in steel. This important metallurgical problem as received heretofore considerable attention in indi- lual research laboratories but the present movement represents the first concerted effort of interested organi- itions to make a thorough study of it, and to combine eir resources in a way to give impetus to a research oblem of considerable magnitude. The need for a research on this subject has been t for some time, but it required the stringency of var conditions to bring the question sharply home to manufacturers and users of steel. It will be re- illed that the American Society for Testing Materials ecognized at its annual meeting in 1918 the abnormal lifficulty in obtaining an adequate supply of steel in time of war, and particularly in meeting the phos- yhorus and sulphur limits as specified in the A. S. T. M. pecifications, owing to the high sulphur coal and low phosphorus pig iron and scrap which had to be used meet war time demands. The society accordingly aised the limits for sulphur in all steels and for phos- phorus in acid steels 0.01 per cent above the require- nents in 43 of its specifications for steel, to be effective luring the period of the war and until otherwise ordered by the society. The Armistice was signed in November, 1918, and in the next six months conditions had so improved that the society restored the original mits for phosphorus and sulphur in 29 of these speci- fications, covering what might be called the special steels such as spring steels, forging steels, and tire and wheel steels. Action on the removal of the note from the remaining 14 specifications, covering in gen- eral the tonnage materials such as plates for buildings ind ships, was deferred until 1920. The committee on steel of the society, however, realized that it was essential to secure reliable infor- mation concerning the effect of phosphorus and sulphur steel in order to make suitable recommendations to the society concerning the limits of these elements in the A. S. T. M. specifications. On consultation with the United States Railroad Administration, represent- ng probably the largest single user of steel, and the Bureau of Standards, it developed that the latter would entirely willing to co-operate actively in conducting 1 investigation. Accordingly the committee on steel recommended to the executive committee of the society that a thor- ighly representative joint committee be formed, con- isting of representatives from those organizations and lustries having a particular interest in the subject. \ hearty desire to co-operate was evidenced by all in- rests approached, and the joint committee was for- y organized on Nov. 29, 1919. A REPRESENTATIVE committee has been ap- 4 The Joint Committee [he personnel of the committee is now as follows: presenting the Bureau of Standards: George K. ‘urgess and H. L. Whittemore, Washington; the United tates Railroad Administration, F. M. Waring, Penn- ania Railroad, Altoona, Pa., and H. E. Smith, Box Eleventh Street Station, Washington; the Amer- Society for Testing Materials, Robert W. Hunt & 90 West Street, New York, and T. D. Lynch, West- ouse Electric & Mfg. Co., East Pittsburgh; the ty of Automotive Engineers, F. P. Gilligan, Henry ither Engineering Co., Hartford, Conn.; the Asso- tion American Steel Manufacturers, E. F. Kenney, vale Steel & Ordnance Co., Philadelphia, and J. J. nan, Jone