Search Documents

By Walter B. M. Davidson

Phosphorus is one of the elements having the widest distribu tion, and phosphoric acid plays an important part in the composition of the crust of the earth. It is allied in various chemical combina- tions with many bases, of which lime, alumina and iron are the most common. It is difficult to state in what chemical combination phosphoric acid predominates in the crust of the earth, for while phosphate of lime, as the mineral which is sought for and found in deposits of economic value is the most familiar, it is probable that the phosphates of alumina and iron are the most usual forms in which phosphoric acid exists in all soils not essentially calcareous. It has been shown by thousands of analyses that all fertile soils contain from a trace to 0.5 per cent. of phosphoric acid. All limestones, dolomites and chalks contain it in proportions which, though usually small, are large enough to make careful analysis necessary in the selection of limestone as flux for iron-smelting. It is generally Trenton limestones that are found best for this purpose, the more recent strata being more phosphatic. In some places phosphoric acid replaces carbonic acid, and the limestone or chalk becomes phos phatic to a large degree, or sometimes pure phosphate of lime. The waters of the ocean, from very early periods, have contained phosphoric acid. Different analyses show varying contents; it is asserted that some portions of the Gulf Stream are more phos phatic than the surrounding waters of the Atlantic. Many springs, usually from limestone regions, contain soluble phosphates in vary ing quantities. I think it safe to assert that phosphorus is nearly the most widely and evenly distributed element on the surface of the earth, and probably the most subdivided. This can be readily understood when the important part which phosphoric acid plays and has played in the vital cosmos is taken into consideration. Phosphorus was on the earth in gaseous, liquid or solid form before the dawn of life, and since then all animal and vegetable creation have combined with the

Jan 1, 1893

By E. Maltby Shipp

YouR committee's secretary submits the following report, or summary, to the members of the committee, in an endeavor to lay before them a general review of the information so far received and also his own knowledge of the work as carried on at a number of plants, this being done in part to secure further information and suggestions from members and lead to a more effective means of furthering the work of the committee. It is suggested that more detailed data be compiled regarding engineering features involved, and that papers be contributed which will deal with the safeguarding of underground electrical installations. There are few operating companies which have not started a more or less systematic campaign to safeguard their employees from accidental injuries and unhealthful surroundings, but a great deal is to be gained by experience. All may welcome the advice and cooperation of those who have been actively engaged in the work and have demonstrated the results obtainable by organized effort, and it is, therefore, exceedingly gratifying to note the ready assistance and hearty cooperation rendered by the companies that may be truly termed pioneers in the movement. No solution of the safety problem is to be found in a skrict standardization of methods, rules or devices, as the various mining, milling and metallurgical practices present too many conditions differing broadly in general principles, but some standard system embodying principles already proven to be efficient should be created, which may be modified or elaborated to meet specific requirements of each individual company, or to fit working conditions as they exist in the various mining camps throughout the country. An industrial plant is primarily a business undertaking, therefore the economic side of a safety or welfare campaign is of importance. Many small operators have been deterred from undertaking the work by their belief that it involved an expense beyond their means, and one that could not be counterbalanced by greater efficiency or saving along other lines. This idea is generally due to a lack of knowledge of the actual costs of such work, and of the results secured by judicious selection of a method commensurate with the size and nature of the opera-

Jan 1, 1918

By Zay Jeffries

IT is well known that many properties of a given metal vary with the size of grain or cell. For most industrial purposes, where high ultimate strength and high elastic limit are desired, the manufacturer tries to produce a. fine-grained structure. For some purposes, for example in transformer iron, a coarse-grained structure is desirable. The terms fine-grained and coarse-grained are used only in a relative sense. For example, a fine-grained cast copper might have grains 100 times larger than coarse-grained high-speed steel. Similarly, a fine-grained steel rail might have grains or cells 100 times larger than coarse-grained wire, which was made of steel from the same heat. In some metals, the change in grain size is more appreciable than the changes in any of the properties determined by the tensile test. Furthermore, in metals which have been annealed or subjected to high temperatures, grain size may prove to be a better indication of the life of the metal in use than the tensile test. One of the authors was able to supplant the tensile test with grain-size determinations in the control of. metal for a specific use, the latter determination being more indicative of. the life of the metal part than the tensile test. A grain-size determination with a tensile test is, of course, more valuable than either singly. At present there is a decided dearth of data on actual grain-size determinations in metals, and consequently a corresponding lack of ability to interpret the determinations after they are made. It would be desirable to have correlation made between grain size and properties of metals, comparing thousands of determinations. In this way, grain-size determinations might be interpreted in much the same manner that tensile tests are now.

Jan 12, 1915

By William Romanoff

As you are no doubt aware, virgin copper, tin and zinc are strategic metals today and little, if any, is available in the manufacture of brass and bronze ingots. The source of alloys used in the manufacture of implements of war are, therefore, from ingots made almost exclusively from the refining of available scrap. It is amusing to hear of the unusual physical properties of various alloys because they mean nothing unless the foundryman is able to produce good sound castings. A discussion therefore means little unless something is said about the relative foundry practice of the various brass and bronze alloys. Among the factors that influence the quality of castings produced are: (I) improper gating, (2) wrong pouring temperatures, (3) poor sand conditions, (4) bad melting practice, (5) faulty pattern equipment, (6) metal. It seems to be the consensus of opinion that about 95 per cent of defective castings can be attributed to the first three causes. Metal while a source of trouble at times, is probably the least responsible for foundry difficulties. As you all know, a molder never makes a bad mold. His first thought is to blame the "damn" metal as this is the path of least resistance. Let's consider the "damn" metal and how it is made. In the manufacture of ingot, scrap is collected at various sources and is shipped to the refiner either directly or through the scrap dealer or broker. It is usually sorted, although not always. In working toward a specified chemical analysis, weighed amounts of various grades of scrap metals are melted, and then oxidized by blowing air through the molten bath to rid the metal of detrimental impurities or reduce them to within specification limits after which they are skimmed off with the aid of some added fluxes. The bath of metal is then poled with wood, chemically tested before and after additions are made to bring it up to required specifications, and finally poured into ingots, after which a final chemical and physical examination is made. As mentioned above, the impurities have either been eliminated or reduced to the point where they meet the specifications of all Government Agencies or Technical Societies. Therefore, why worry as to whether castings are to be made from strategic virgin metals or secondary ingots from available scrap. Tests have continuously been made and it is a proven fact that physical properties are no better from virgin metals than from secondary ingots of the same composition. It is definitely more fool-proof to make castings from secondary ingot than from virgin metals because if an error is made in weighing the copper, tin, lead or zinc of the latter, the analysis is off balance. If an error is made in weighing secondary ingots, you merely have more or less metal but the analysis remains constant. Furthermore, when pure copper is melted. it is susceptible to reducing gases as well as oxides. Secondary ingot is already alloyed with natural deoxidizers such as zinc, etc., and the volatilization of the latter also tends to eliminate reducing gases mechanically.

Jan 1, 1943

By Albert L. Toenges

COAL mining technique progressed slowly until the advent of mechanized mining. The cutting machine was a forward step, but had only a limited effect upon improving the percentage of coal recovery. Previously, the physical fitness of the loaders and the total output of the miners fixed mine production. The miner was an independent contractor and supervision over his working place was superficial. Rising costs and the inroads of substitute fuels demanded increased output per man to lower the unit production cost. Therefore, the amount of coal loaded mechanically in underground bituminous mines has risen from 0.3 per-cent in 1923 to 7.4 in 1929, to 20.2 in 1937, and to 48.9 percent in 1943. When loading devices were introduced it became necessary to adapt them to existing systems of mining, or to alter the mining system to fit the machine. An increased amount of supervision was required as output depended upon proper operation of the machine rather than on the physical fitness of the individual.

Jan 1, 1946

By Paul Billingsley

THE purpose of this paper is a comparison, based on genesis, of the ore deposits associated with the igneous rocks of the central Montana Rockies. Considered separately, without attention to their origin, the orebodies appear to be distributed haphazard, with no fundamental laws controlling their position and character. It is believed, however, that if all the factors be weighed, this apparent confusion will to a large degree disappear. The, first essential to such a comparison is detailed knowledge of the individual mines, as to their geographic position (see Fig. 1), their mineralogical character, and in particular the derivation of their ores.1 The authors of this paper have pursued such an investigation for the past 6 years, and have accumulated a mass of evidence that enables a preliminary correlation to be attempted. It appears that the majority of ore deposits are genetically related to one or another of the igneous

Jan 4, 1917

Engineering Experiment Station, University of Arkansas, Fayetteville, Ark. W N Gladson, Dean and Director The Engineering Experiment Station has published a number of bulletins, only a few of which are of particular interest in this directory: Bulletin 3, Arkansas coal or oil for domestic heating; 4, Road materials of Arkansas, 5, A study of Arkansas coals, 6, Portland cement materials in Arkansas; 11, Natural gas versus Arkansas coal for house heating. Circular 3, Short cuts to combustion efficiency with natural gas Address the Engineering Experiment Station for any of these publications.

Jan 1, 1933

By J. W. Gwinn

The underground haulage system in the lead-silver mine of the Bunker Hill & Sullivan Co., situated at Kellogg, Idaho, is the most extensive in the Cæur d'Alene district, comprising about 35,000 ft. of tunnels, drifts, and cross-cuts where locomotive haulage is in use. The main working adit, known as the Kellogg tunnel, or No. 9 level, is approximately 10,000 ft. in length from the portal to the main working shaft and extends beyond that about 4,500 ft. in each of two directions. On this level all the ore from the Bunker Hill & Sullivan, the Sierra Nevada Consolidated, and the Caledonia Mining Co.—an average of 44,600 tons per month—is hauled to the mills, located a short distance from the portal. Electric haulage by the trolley-type locomotive is used on this level throughout. Below this level, at intervals of 200 ft. vertically, are five other working levels (Nos. 10, 11,12,13, and 14); and the total haulage distance on these, where electric locomotives are used, is approximately 16,000 ft. No. 13 level has but recently been opened up and is not working to capacity; while the main cross-cut on No. 14 has just been started, and has no need of power haulage. Of the four levels equipped with electric haulage, Nos. 11, 12, and 13 have storage-battery locomotives, and No. 10 still retains the trolley type by reason of the small and decreasing tonnage produced. Electrification - Electric power is supplied to the mine by two systems. The first, the 500-volt direct-current trolley, was installed in 1897 when the Kellogg tunnel was started, and was extended as the tunnel advanced, being used for the first trainload of ore on Nov. 17, 1902, since which time it has been in continuous service. The current for the line is transmitted on a No. 00 copper wire as far as the shaft, and on No. 0 wire throughout the remaining length of the Kellogg tunnel; and until the installation of the storage-battery locomotives it was used in practically all the cross-cuts and drifts on each level below No. 9.

Jan 1, 1915

By Milton R. Pickus, Earl R. Parker

THE modern theories of creep¹-4 in general have been based upon the concept of generation and migration of dislocations, with the generation process normally assumed to be rate controlling. The theories are generally deficient in that they fail to take into account many factors that are known to influence creep. The influence of the state of the surface of the test specimen has been almost completely overlooked; yet the present report shows that the nature of the surface may, in certain cases, govern the creep characteristics of a specimen. In the period since Taylor" applied the concept of dislocations to a study of metals, a school of thought has developed that closely relates the plastic deformation of metals to the generation and migration of dislocations through the crystal lattice. It might be expected that the thermal energy required for the generation of a dislocation would be different from that for migration of the dislocation through the lattice. Furthermore, the activation energy for generation would be expected to vary for different parts of the solid metal. It has been predicted that dislocations would be generated most easily at external surfaces, but could also be activated at certain internal surfaces such as grain or phase boundaries. Within the body of the metal a range of values for the activation energy might be expected because of different degrees of disorder at such regions as grain boundaries, impurities, and second-phase particles. The particular value of the activation energy that was rate determining could then depend on the specific conditions of a test. If, for example, the surface atoms were by some means constrained, the generation of dislocations in the body of the metal might become the important factor. On the other hand, other conditions may favor generation at the surface. It is possible then that the creep behavior may not be completely determined by the inherent properties of the metal. Even the environment in which a test is carried out could have a significant effect. In fact it is conceivable that in order to obtain the maximum creep resistance from a given alloy, the surface atoms must be so constrained that the activation energy for generating dislocations on the surface is at least equal to that required for generation in the body of the metal. On the basis of such considerations, and in view of the limited number of publications discussing this subject, it seemed that an investigation of the influence of the state of the surface on creep might yield information of both theoretical and engineering interest. Experiments on single crystals, demonstrating a variation in the mechanical properties due to alterations in the surface layer, have been reported by several investigators.6-13 he results of these experiments have been briefly summarized;14 consequently, the earlier work will not be reviewed here. As an example of these findings the observations of Cottrell and Gibbons may be cited. They reported the critical shear stress of a lightly oxidized cadmium single crystal is greater by a factor of 2½ than a specimen with a clean surface. Materials and Methods Single crystals M in. in diam and 8 in. long were prepared from Horse Head Special zinc, melted under an atmosphere of helium in a large pyrex test tube, and drawn up into a long ½ in. diam pyrex tube by means of a vacuum pump. The cast zinc rods thus produced were cut into convenient lengths and sealed in evacuated pyrex tubes. Single crystals were grown by gradual solidification of the remelted rods. Cleaving the ends of the single crystal specimens chilled by liquid nitrogen proved a simple method for determining orientations from the exposed basal plane from the markings left on the cleaved surface that gave the slip directions with sufficient accuracy for the experimental work. The specimens chosen for the experiments were those having the angle between the basal plane and the specimen axis within the range of 15" to 65". Since zinc single crystals are quite delicate, it was necessary to devise an appropriate method of gripping the specimens in order to suspend them in the furnace and apply the load. Stainless steel collars were prepared having an inside taper, the smaller end of the taper being of such a size that the specimen could just pass through freely. The tapered hole did not extend the full length of the collar; a sufficient thickness of metal remained so that a hook could be attached to provide a means of applying the load and suspending the specimen. One of the collars was slipped over the upper end of a specimen which was supported vertically in a steel jig. The collar was then heated electrically until the end of the crystal melted and filled the collar with molten zinc. At this point the application of heat was discontinued, whereupon the molten zinc quickly solidified, due to the chilling effect of the jig. The specimen was then inverted and the second collar applied in a similar manner. The jig served several purposes: limiting the length of specimen that was melted, providing excellent alignment of the collars with respect to the specimen axis, and protecting the specimen from mechanical damage. Once the specimen was suspended in the furnace and loaded, it was desired to accomplish the surface treatment with a minimum of disturbance of the specimen. Around the specimen was a long pyrex tube, the upper portion of which was approximately 1 in. in diam, and in it was a copper coil of such a diameter to fit snugly against the tube. A specimen, approximately ½ in. in diam and 4 in. long, was suspended by means of a stainless steel rod so that it hung within the copper coil. The lower portion of the glass tube was approximately ¼ in. in diarn, and passing through it was a 5/32 in. diam stainless steel rod which hung from the lower specimen collar. This portion of the glass tube and the stainless steel rod extended through the bottom of the furnace. A T-connector, with suitable packing, was attached to the lower end of the stainless rod to provide a water-

Jan 1, 1952

By H. M. Howe

Page 1. Introduction............................514 2. Definitions.............................517 3. Brevity of the Heating........................517 I. THE HARDENING OF THE BORE..............517 4. The Hardening of the Bore.....................517 5. The Thickness of the Hardened Layer.................517 6. Martensitization..........................518 7. The Hardening Repetitive ......................519 8. The Temperature Cycle.......................519 9. The Hardened Layer is the Merged Layer............... 521 10. The Progressiveness of Merging....................521 11. The Progressive Thickening of the Hardened Layer from Round to Round. 523 12. Merging and Hardening are Cumulative................523 13. Three Additional Causes of the Progressive Thickening of the Hardened Layer 525 14. Progressive Roughening of the Bore..................525 15. Avoidance of an Endothermic Transformation.............525 16. Asymptotic Retardation of the Thickening of the Hardened Layer.....527 17. The Troostitic Layer........................ 529 18. The Usual Lack of Martensitic Markings................529 19. The Thickness of the Hardened Layer Should Increase with the Quantity of Heat Taken up by the Walls of the Bore.................530 20. The Decrease of the Thickness of the Hardened Layer from Breech to Muzsle 531 21. Phstic Deformation as a Contributory aCause of Hardening........531 22. In What Way May Plastic Deformation Hasten Hardening?....... 535 23. Possible Need of Coarsening.....................535 24. Carburization as a Cause of Hardening..........:.....536 25. Does Hardening Increase Erosion?..................-538 11. THE CRACKING OF THE BORE ...............539 26. Appearance of the Bore and Cracks in Elevation............539 27. The Cracks in Elevation in the Rear Ring...............539 28. The Cracks in Elevation in the Forward Ring.............540 29. The Copper Network in the Grooves.................540 30. The Cracking of the Lands......................541

Jan 1, 1918

By E. R. Williams

Continuous casting of nonferrous metals has become a commercial reality. After years of slow and arduous experimentation by a number of independently working inventors, starting with Lord Henry Bessemer in 1865, success has finally been achieved. Nonferrous metals—aluminum, copper and brass—extremely vital to our production of war equipment, are being continuously cast every day in large quantities. In fact, some nonferrous metals —for instance, high-strength aluminum alloys—could not have been produced in the huge quantities required for planes and other war equipment if it were not for continuous casting. These casting processes for nonferrous metals have not been entirely perfected but continuous casting is here to stay. Continuous casting of carbon and alloy steel has not yet gone into commercial production but it is well on its way. A great deal of hard work has been expended and -small fortunes in money have been and are being spent in marching down the long road to success. Considerable tonnage of plain carbon, stainless and other alloy steels of high quality have been produced by pilot-plant continuous-casting units and at speeds that give indisputable evidence of commercial success. What has made the difference between failure and success? What is there left to do to revolutionize completely the method of casting metals, which has existed for centuries? These questions are being rapidly answered. Fundamental Methods Present continuous casting processes have many common problems but differ considerably in their methods of solution. The two fundamental methods are: I. Forming the solidifying metal against mold walls that move with the metal, so that there is no relative movement between the walls and the metal. This is a development of Lord Bessemer's idea of pouring metal between two rotating rolls. 2. Moving the solidifying metal along a stationary mold wall so that there is relative movement between the wall and the metal. This was proposed by Trotz in Germany as far back as 1889. Neither Bessemer nor Trotz achieved commercial success. The chief reason seems quite apparent today, inasmuch as they did not solve the fundamental problem of rapid heat removal from the molten metal. The Williams Continuous Casting Process is based upon this fundamental idea of fast heat removal and dissipation. The bessemer method of forming the ingot against a moving mold wall—either rotating rolls or endless moving plates—was carefully considered by the author and promptly abandoned as being commercially impractical. Primarily, only a very small tonnage output was possible except at terrific lineal speeds, because the very nature of this method required casting thin sheets rather than ingots. Secondly, the casting of a sheet between lolls that are pressed together meant the rolling of two layers of solidified skin separated by a molten core. Internal bursts and segregation of the metal usually resulted. Moving Solidifying Ingot Along Mold Wall It was decided therefore to devote our research activities chiefly to- the idea of moving the solidifying ingot along. a stationary mold wall. It was soon dis-

Jan 1, 1945

By Pablo Hadzeriga

Great Salt Lake brine was subjected, in laboratory scale, to conditions simulating solar evaporation. Solid phases and the variation in composition of the liquid phase throughout the potassium salts crystallization zone are presented. These experimental results are discussed and compare with stable equilibrium data of the quinary system Cl-, SO4, Na+, K+, Mg + + and H2O. The Great Salt Lake brine in Utah is a vast reserve of several potential chemicals which has attracted much attention in the recent past. From the standpoint of an ore reserve, it may be said that the lake contains a low grade ore which has to be concentrated by evaporation of water. Because of the fairly favorable weather conditions in the Great Salt Lake area, it seems reasonable to consider solar evaporation as an economical means of concentration. From the view of phase chemistry, the main constituents of Great Salt Lake brine make it belong to the five component system: C1-, SO4=, Na+, K+, Mg++ and H2O. Because of their low concentration, the presence of other elements may be regarded as having little effect on the equilibrium of the five main components. Equilibrium data for the quinary system of our interest has been available for many years. Using these data, it is possible to calculate how the brine of the lake will concentrate when subjected to solar evaporation. In practicing solar evaporation, the weather factor and supersaturation conditions cannot be ignored, but their introduction into calculations using equilibrium diagrams is almost an impossible task. With the experimental work presented in this paper, an attempt is made to compare the stable equilibrium data of the quinary system as applied to the case of the Great Salt Lake brine and the dynamic equilibrium when that brine is subjected to continuous solar evaporation. Sea water brine belongs to this quinary system when only the major constituents are considered. The study of this system has been carried on since the last decades of the nineteenth century. The reason for these intensive studies was to give a geological explanation to the underground potash deposits. AS a result, many theories were presented trying to relate the equilibrium data with the geological formation, paragenesis and metamorphism of these deposits. Two main approaches were followed for the equilibrium studies of this quinary system. One of them, and the best known to us, was the school started in Germany in the last century by J. H. Van't Hoff. The other one, which started about the same time, was the school of N. S. Kurnakov in Russia. Both approaches were different and as a consequence generated opposite theories about the geological formation of potash deposits. The Van't Hoff school studied the quinary system of sea water under careful laboratory control, resulting in stable phase diagrams. During these studies, Van't Hoff recognized the difficulties in crystallizing some double salts.' ". . . . we unexpectedly found that some compounds whose formation in the solutions under investigation was possible at 25°C, nevertheless totally failed to put in an appearance. These, not to mention the calcium salts, were leonite, MgSO4 . K2SO4 4 H2O; kainite, KC1-MgSO4 . 3 H2O; and kieserite, MgSO4 .H2O. Even exceedingly slow crystallization with the addition of the compounds themselves did not remove the condition of supersaturation in the case of these bodies." However, those salts (leonite, kainite, and kieserite) were included in the stable phase diagram at 25°C as shown in Fig. 1 using D'Ans data.3 The figure also shows the sequence of crystallization of the Great Salt Lake brine according to the stable diagram. In later studies by the Van't Hoff school, especially by D'Ans,3 Karsten,4 Autenrieth,5,6 attention

Jan 1, 1968

By W. A. Goodyear

It is safe to assert that in cities generally, the fuel of the future for all domestic, as well as for most manufacturing and metallurgical purposes, will be gaseous fuel. The immense advantages which gas possesses in facility and cheapness of distribution, cleanliness, and economy of manipulation, and the facilities which it offers for utilizing in almost all cases a much higher percentage of the total quantity of heat produced, than it is possible to do with any kind of solid fuel, are facts which will vastly more than compensate for the comparatively small loss of heating power, which will be found necessary in the turning of the solid fuel into gas upon a large scale, and which, in the bpinion of the writer, will, at no distant day, command attention, and will ultimately result in a revolution in our use of fuel. The employment of gaseous fuel upon a scale of any considerable magnitude, has hitherto been almost entirely confined to the utilization of the waste gases of the iron smelting furnace for heating the blast, and the rapidly increasing use, for certain metallurgical pur-

Jan 1, 1883

By Harold W. Smith

Ore beneficiation via grinding and flotation has traditionally been considered an art because, until recently, the beneficiation plants that operated effectively were those run by skillful personnel who had acquired an "eye" and a "feel" for the process. Today, thanks to technological developments of the past five to ten years, ore beneficiation can be tackled more scientifically. In properly chosen applications, two developments that can bring significant operational and control improvements to concentrating plants are: • X-ray fluorescent spectrometers-that continuously measure chemical composition of flotation process streams, and • Minicomputers-that are relatively inexpensive and highly reliable in data gathering and process control.

Jan 11, 1974

By J. M. Glass, C. D. Sholtess

We at Hughes Tool Co. are extremely proud of the quality of the hardware and techniques introduced through our efforts in tunnel-machine development and of the ready acceptance of them by manufacturers and contractors throughout the world. All of us who attended the conference and who are represented in the book, we believe, anticipate an increasing need for improved methods of underground excavation. The development of such methods will permit the further exploitation of our underground resources plus providing underground space for transportation and habitation at a rate compatible with demand. We hope that our comments, derived from the application of Hughes Tool Co.'s rotary boring experience, may provide a better understanding of the boring method as a possible avenue through which the desired improvement in underground excavation may be attained. We hope you may also become aware of some of the problems Hughes, as a pioneer developer of raise, shaft, and tunnel-boring equipment, must face prior to further major undertakings in this very interesting field. Our task is to acquaint you with the present status of the Hughes Tool Co. development program as it relates specifically to tunnel-boring machines. We feel this task can best be accomplished by a brief review of the general sequence of events leading to and constituting an equipment development program and more specifically the manner in which these events have occurred to either influence or further our boring-machine development program. The development of a machine to accomplish a certain function or series of functions is usually a very long and tedious process to which any number of individuals must contribute, perhaps over a period of centuries. Of particular irony is the fact that often those who contribute most generously do not necessarily reap the greatest immediate benefit. A marketable ma- chine will, however, result from a sequence of events such as these: 1) A problem or need is defined. 2) An idea is born to eliminate the problem.

Jan 1, 1970

By Floyd E. Bliven

A century ago, Thomas Carlyle sketched the Emblem of the Wasting Candle in one of his papers. "Terar Dum Prosim" he wrote under the candle-" May I be wasted so that I be of use." The application of his reasoning is an excellent guide for a discussion of the scrap problems of today. The General Electric Co. has addressed itself to the need of proper and careful preparation of scrap metals for many years. A supervisor of salvage directs this work in each of the works. Generally he is an engineer and has had broad factory training. He gives general direction to the collection, preparation and disposition of scrap materials. He operates the extensive facilities which each works has provided for the centralization and control of scrap accumulations, and also initiates studies leading to the reduction of scrap accruing from machining and assembly operations. r We recognize that each industry, each factory, each locality faces a different set of conditions. Irrespective of size, in a plant employing 20 men or a large works with 15,00 employees-certain fundamental principles can be applied for organization and the collection of scrap. The manufacture of electrical apparatus is a highly complicated intricate business. In one area we make electronic tube and adjacent buildings house the manufacture of steam turbines. Both are instruments for power-different in size and in many cases serving different fields of application. Unlike the great industries that build automobiles, trucks, or engines where repetitive operations, once solved, set the stage, electrical manufacturers' plants are large jobbing shops. Therefore, we must carefully plan every step in handling the scrap that "in so wasting to produce the finished motor or locomotive-we can return this product to reprocessing and ultimate use." ESSENTIALS FOR SALVAGE EFFICIENCY The essential steps for an efficient salvage department are: I. Selection of Personnel.-An able foreman would be a man of broad experience and understanding-one who commands the respect of the entire foreman group as well as that of his own men. In the interest of clean scrap, it is necessary to acquaint the foremen in the separate manufacturing units with the need of careful segregation in the shop and the best methods of obtaining it. At least 40 per cent contact time should be devoted for this purpose. 2. The physical equipment of the salvage department should be devised and selected to handle complete, at one point, all scrap operations. Bulky materials as produced by some large shops can be economically placed in salable shape at the divisional point. Because salvage

Jan 1, 1943

By S. G. Valentine

BLAST-FURNACE blowing engines are broadly of two main types: either steam- or gas-driven reciprocating engines, or turbine-driven rotary engines. Some results of experience with a furnace blown by an engine of the latter type may be of sufficient general interest to relate. The first engine of this type was installed at Oxford Furnace, New Jersey, before the writer's connection with this plant, in March, 1910. This furnace uses chiefly New Jersey magnetites and had been in blast seven months on its old engines when the turbo blower was started. It was 80 ft. high by 17 ft. 6 in. bosh and 11 ft. hearth diameter. It is of interest to see from the records what happened when the turbo engine was put to work. But of course, as the old blowing equipment was rather antiquated, consisting of two I. P. Morris engines with air cylinders 72 by 72 in., in good running order, however, it is evident that the comparison between their work and that of the turbo blower cannot be interpreted as being between machines that were respectively of equal excellence as representatives of their types. Still the results were gratifying and -interesting. The records show that, with the old engines blowing 13,630 cu. ft: of air per minute, measured by piston displacement, the furnace was working up about 480 tons of stock per 24 hr. and producing an average of 132 tons per day and a maximum of 166 tons. The rotary blowing engine installed was a General Electric Co. machine, the driving end being a Curtis steam turbine and the air end a six-stage rotary compressor, all running at about 1,500 to 1,600 rev. per minute, and having a capacity of 25,000 cu. ft. of air per minute up to 25 lb. pressure, and equipped with an automatic constant-volume variable-speed governor. After running this blower, for a period equal to that covered above by the old engines, at an average rate of 15,000 cu. ft. of air per minute, the furnace worked up an average of about 592 tons of material and produced an average of 170 tons per day. Thus, on an apparent increase of 10 per cent. in the air volume there was an increase of about 23.5 per cent. in the materials worked up and of about 28.8 per cent. in the product. For the first calendar month's operation of the turbo blower, on an average of 15,040 cu. ft of air per minute, there is

Jan 2, 1914

By L. L. McDaniel

DURING the past few years a number of improvements in smelting and power equipment have been made at the Douglas smelter of the FIG. 1.-GENERAL PLAN OF SMELTER. Phelps Dodge Corporation at Douglas, Ariz. In the summer of 1935 work was started on the first unit of a new reverberatory waste-heat boiler plant which ultimately was to furnish steam for a modern high-pressure power plant. A second reverberatory waste-heat boiler unit

Jan 1, 1939

By Jack D. Webber

The successful use of oil well packers requires, in part: an understanding of the pressures which exist at the packer in various applications and an understanding of the characteristics of the various types of packers. It is with these pressures, the resultant forces, and the characteristics of packers. that this paper is primarily concerned. An oil well packer may be defined as a mechanical device for blocking the passage of fluids in an annular space. In the more usual case, the annular space is that between the tubing or drill pipe in a well and the casing, and packers which block such an annular space are broadly referred to as casing packers. In the other case. the annular space is that between the tubing or drill pipe and the walls of an open hole, and packers for blocking this space are generally called formation packers. While the hydraulics involved are essentially the same for casing and formation packers. a greater variety of conditions are encountered in the use of casing packers and only casing packers will be discussed. After a packer has been set and a pressure seal effected between tubing and casing, the packer is comparable to a piston in a cylinder. Pressures acting upon a piston result in forces which will move the piston unless some means is provided to prevent such movement. In the same manner, pressures acting upon a packer will move the packer unless there is present a sufficiently great restraining force. PACKER CLASSIFICATIONS Packers may be classified according to the pressure conditions under which they are capable of blocking the annular space between tubing and casing. Fig. 1 shows schematically two types of packers in common use. These packers are capable of blocking the annular space against the passage of fluids under a differential pressure of significant magnitude only when the pressure in the annular space above the packing element is greater than the pressure below. It may be seen that in Fig. l-a. slips with teeth which bite into the casing and prevent downward movement are provided. In Fig. 1-h. an anchor prevents downward movement. In each case, there i-only the tubing to prevent upward movement when differential pressures act to move the packers upwardly. Packers which hold only a significant differential pressure acting downwardly have been in use since the early days of the oil industry and will hereafter be referred to as conventional type packers. In many packer applications operating conditions will 1.crult in differential pressures across the packer which will at times act to move the packer upwardly, and at other times, act to move the packer downwardly. For these applications, designs are available which will block the annular space and resist movement in either direction. Fig. 2-a shows schematically a packer of this type which is designed to be run into a well and set, and removed when desired by merely pulling the tubing. It will be noted that two sets of slips are provided-— one set above the packing element to prevent upward movement, and another set below the packing element to prevent downward movement. This packer is built around a mandrel which is essentially a part of the tubing. and which is free to move longitudinally within certain limits through the set packer. Fig. 2-b shows schematically a permanent type packer which is capable of holding pressures from either direction. Here again, two sets of slips are provided to prevenl movement of the packer. This packer is designed to become virtuallv a part of the casing when set and it is made of drillable material so that it may be drilled out when its removal is desired. The seal nipple shown effects a pressure seal between the tubing and the packer. This seal nipple is a part of the the tubing, and the nipple and tubing may be withdrawn from the well without disturbing the packer. It should be noted that these figures are not representative of all available packers which are designed to hold pressures from both above and below. Packers which resist movement in either direction will hereafter be referred to as universal type packers. There is a third type of packer in general use and this type is designed to block the passage of fluids when the pressure below the packing element ii greater than that above. This type is provided with slips which prevent upward movement of the packer and is somewhat similar to a conventional type packer run upside-down. Packers designed to hold pressure only from below are made in a variety of designs and are usually owned and operated by service companies.

Jan 1, 1949

By Jack D. Webber

The successful use of oil well packers requires, in part: an understanding of the pressures which exist at the packer in various applications and an understanding of the characteristics of the various types of packers. It is with these pressures, the resultant forces, and the characteristics of packers. that this paper is primarily concerned. An oil well packer may be defined as a mechanical device for blocking the passage of fluids in an annular space. In the more usual case, the annular space is that between the tubing or drill pipe in a well and the casing, and packers which block such an annular space are broadly referred to as casing packers. In the other case. the annular space is that between the tubing or drill pipe and the walls of an open hole, and packers for blocking this space are generally called formation packers. While the hydraulics involved are essentially the same for casing and formation packers. a greater variety of conditions are encountered in the use of casing packers and only casing packers will be discussed. After a packer has been set and a pressure seal effected between tubing and casing, the packer is comparable to a piston in a cylinder. Pressures acting upon a piston result in forces which will move the piston unless some means is provided to prevent such movement. In the same manner, pressures acting upon a packer will move the packer unless there is present a sufficiently great restraining force. PACKER CLASSIFICATIONS Packers may be classified according to the pressure conditions under which they are capable of blocking the annular space between tubing and casing. Fig. 1 shows schematically two types of packers in common use. These packers are capable of blocking the annular space against the passage of fluids under a differential pressure of significant magnitude only when the pressure in the annular space above the packing element is greater than the pressure below. It may be seen that in Fig. l-a. slips with teeth which bite into the casing and prevent downward movement are provided. In Fig. 1-h. an anchor prevents downward movement. In each case, there i-only the tubing to prevent upward movement when differential pressures act to move the packers upwardly. Packers which hold only a significant differential pressure acting downwardly have been in use since the early days of the oil industry and will hereafter be referred to as conventional type packers. In many packer applications operating conditions will 1.crult in differential pressures across the packer which will at times act to move the packer upwardly, and at other times, act to move the packer downwardly. For these applications, designs are available which will block the annular space and resist movement in either direction. Fig. 2-a shows schematically a packer of this type which is designed to be run into a well and set, and removed when desired by merely pulling the tubing. It will be noted that two sets of slips are provided-— one set above the packing element to prevent upward movement, and another set below the packing element to prevent downward movement. This packer is built around a mandrel which is essentially a part of the tubing. and which is free to move longitudinally within certain limits through the set packer. Fig. 2-b shows schematically a permanent type packer which is capable of holding pressures from either direction. Here again, two sets of slips are provided to prevenl movement of the packer. This packer is designed to become virtuallv a part of the casing when set and it is made of drillable material so that it may be drilled out when its removal is desired. The seal nipple shown effects a pressure seal between the tubing and the packer. This seal nipple is a part of the the tubing, and the nipple and tubing may be withdrawn from the well without disturbing the packer. It should be noted that these figures are not representative of all available packers which are designed to hold pressures from both above and below. Packers which resist movement in either direction will hereafter be referred to as universal type packers. There is a third type of packer in general use and this type is designed to block the passage of fluids when the pressure below the packing element ii greater than that above. This type is provided with slips which prevent upward movement of the packer and is somewhat similar to a conventional type packer run upside-down. Packers designed to hold pressure only from below are made in a variety of designs and are usually owned and operated by service companies.

Jan 1, 1949