« ΠροηγούμενηΣυνέχεια »
purposes of my present invention may be conveyed by a gutter in a fluid state direct from the smelting furnace where it has been obtained from the ore,” without the expense and delay incident to the intermediate cupola process, practical experience, in this country at least, showed that the refining of iron without first casting it into pigs, selecting or mixing the pigs, and remelting them, was attended with such expense that the entire abandonment of the practice was seriously considered. The difficulty was in the material variations between different portions of the same cast, and even different parts of the same pig, -an irregularity which was increased when the metal was drawn from several furnaces. There was added to this frequent changes in the char: acter and composition of the ore, coke, and limestone flux with which the furnace was charged. The consequence was that the nonuniform chemical composition of the metal from the molten blast furnaces yielded products of steel, such as rails and beams, which were not only irregular chemically, but of irregular and uncertain final condition,-some sound, others of imperfect strength and full of flaws. These irregularities were in a measure obviated, not only by a careful selection of
some independent equalization of the composition of each ladle or of the ladles of each group, but it affords no further advantage, and in fact would not obviate the difficulties of direct metal working. It does not enable the converter manager to foretell the character of each charge from the character of the preceding charge, and would therefore entail the uncertainties of operation and the irregularity of the product which the Jones method avoids.”
It had .# been an object of manufacturers that steel should be made directly from the molten metal, as it comes from the blast to furnaces, without having to pass through o the intermediate.or cupola process, which * involved the castin P the furnace metal into pigs. These, after becoming cold, were assorted, broken up, recharged and remelted in a cupola furnace, and then placed in a converter for conversion into steel. By this cupola process a product, practically uniform in character and suitable for further treatment in the converters, was secured, but at the expense (more than 60 cents per ton) of rehandling and remelting the iron as it came from the blast furnaces, in cupolas, and the contamination of the metal with sulphur evolved from the coke in the process of remelting. The obstacles con
nected with this method and the difficulties attendant upon the use of the direct process are thus comprehensively set forth by Mr.
ea pigs beforehand, but by the necessity of : employing upon receiving ladles or reservoirs * into which the, product of one or more cupo
la furnaces was drawn off into such reservoirs, which were made large enough to hold the product of two or three furnaces, and from which the molten metal was withdrawn into the converters. Had the amount required for the converters in each case been the exact product of one or more cupolas, no reservoirs would have been necessary, but as the demand was variable, a storage of molten metal was required to retain the product of one or more cupolas, until it was required for the converters. Of course, as the product of two or more furnaces was drawn off into these receiving ladles, there would be some intermixing of those products, although the receiving ladles do not appear to have been used for that purpose, the operators relying more particularly upon the careful selection of igs beforehand, to obtain the requisite uni; for conversion into steel. The ladles being open at the top, the molten metal could not long be retained in them, and in the best practice it was so arranged that the withdrawals from the reservoir were made every few minutes, and without regard to the amount left in the reservoir after each withdrawal. It will be borne in mind that the object in either case, whether by direct or indirect process, is to obtain, as far as possible, a uniform product of iron for the converter. “These results,” said one of the witnesses (Kennedy), speaking of the process used before that of Jones, “are not obtained by the practice of taking metal from two blast furnaces by running a train of ladles in front of them and tapping into each ladle half a charge and following it from a second furnace. By such practice, of course, there is
Julian Kennedy, one of the experts: “Ever since the invention of the Bessemer process it has been well recognized that great economics could be attained by transferring the molten metal from the blast furnace to the converter without allowing it to solidify. Until within a few years, however, this direct process, as it has been called, has not been generally used. It is easy to see why this was the case. The fluctuation in the chemical composition of the metal from the blast furnace was too great to allow that degree of uniformity of product in the Bessemer steel produced from it which is absolutely necessary in the case of steel rails, for example, which must be as reliable as human skill can make them, and where no reasonable expense can be spared to make them perfectly safe and trustworthy. A very few broken rails in a track, with the damage to property and human life which this might cause, would far more than offset any possible saving in a year's work, due to the use of the direct process. For this reason the practice, until within comparatively recent years, has been to cast the metal in pigs, then to analyze it and reject any portion not closely approximating a rigid specification in its chemical composition, and to select, mix, and then melt the approved metal in cupola furnaces. By this means very Fo: uniformity of chemical composition of the remelted metal can be obtained, and good and reliable steel made from it with regularity and certain- : t .” • Speaking of a time when the direct pro- : cess (before that of Jones) had been in use for several years he said: “After studying the results which had
been obtained at the Edgar Thomson works and elsewhere in the use of the direct process, I consulted with Mr. James Gayley, and we agreed that in the building of a new works it would not be profitable to use direct metal, but that, on the contrary, the disadvantages resulting from the irregularity in the product were so great that it would be better to go to the expense of building and using cupola furnaces. We did not then perceive any means adequate to overcome these disadvantages.” The difficulties connected with the prior devices are also stated in an article by Mr. Holley, published in 1877, from which we extract the following paragraph: “Third. The embarrassing feature of the direct process is the irregularity in the heat —that is to say, in the silicon of the charges—resulting in the large amount of scrap due to too little of this element, and in the increased number of second-quality rails due to too much of it; while in France, where 3 to 5 per cent of manganese is the heating ingredient, there may always be an excess of this latter element without injuring the quality of the steel, although the variation of heat is here, also, a serious difficulty. In other words, it has not yet been practicable to work the blast furnace with sufficient regularity to realize approximately the theoretical advantages of the direct process.” “Fourth. The obvious remedy is to mix a
received and mixed with the molten metal in the dominant pool, they were, when discharged from the reservoir, approximately, though not perfectly, uniform, the original variations having been lost in their mixture with the dominant pool. “It is therefore plain,” says the district judge in his opinion, “that with a mixer thus operated, it is possible to have wide variations in the composition of the blast furnace metal charges added, and at the same time the successive withdrawals for the Bessemer converter show quite small and gradual changes of composition. The heat of the detained mass is affected by the incoming charges just from the blast furnace, but the heat of such addition, whether relatively high or low, must mingle with, be modied by, and average with, the heat of the larger and dominating mass.” It is not insisted that this method gave absolutely uniform results, “nor,” says the witness Fry, “did the inventor, as I understood him, comprehend such, but, on the contrary, he recognized the practical impossibility of rendering uniform a continuous supply of metal, and desired only to reduce the abrupt changes of the several portions added to the gradual changes of the portions withdrawn, and this is what he worked out from his invention in a thoroughly practical way.” While the patent in suit is for a process, and not for a mechanism, the process will
number of blast-furnace charges, so as to reduce the irregularity to a minimum. Two systems of doing this are on the eve of trial:
be the more easily understood by a refer- e. ence to the apparatus above reproduced, of
which consists of a "reservoir, or closed re-“ ->
The one is simply mixing so few charges in a tank that the metal will be drawn out before it chills; the other is to store a larger number of charges in a heated tank,+that is to say, in an immense open-hearth furnace.” “A few words of history may be of interest. Mr Bessemer's early intention was to use blast-furnace metal direct. The earlier Bessemer practice, especially that in Sweden, was with metal right from the blast furnace. But this practice did not we make headway, except where there was from & 3 to 5 per cent of manganese in the pig * blown, for reasons just" mentioned; so that while it soon became standard at Terrenoire and elsewhere in France, as well as in Sweden, and to some extent in Germany, yet in England it was not only unused, but ronounced impracticable so late as SepÉ. 1874.” This difficulty, and it seems to have been so serious as to render the direct process commercially impracticable,_-Jones sought to remedy, and did remedy, by creating a covered reservoir of molten metal between the blast furnaces and the converters, in which should always be maintained a lar uantity of metal, happily termed by , the }. judge a dominant pool, which should be drawn off in small quantities at a time, and replenished by a like quantity of metal from the blast furnaces. In this way, while the metals taken from the sevo blast furnaces might differ in their heat and constituent elements, yet, being
ceptacle, commonly termed a “mixer, lined with fire brick of sufficient thickness to retain the heat of the molten iron, and of such size and strength as to be capable of receiving and retaining a large amount —“say, 100 tons” — of molten iron. This reservoir is mounted upon journals, and is adapted to be tipped so as to receive at one end molten metal from the blast furnaces, carried to it in cars, and by being tipped in the other direction, to discharge the same into similar cars, in which it is carried to the converter. The essence of the invention lies in the fact that the tip is so regulated by a stop that the reservoir can never be wholly emptied, but a “considerable quantity” of metal always remains,—a dominant pool, into which successive additions are received. That the invention is one of very considerable importance is attested by the fact that it was not only put into immediate use in the Edgar Thomson works at Braddock, then owned by the plaintiff, but has since been adopted #y all the leading steel manufacturers in this country, and by many similar works in *:: where the patent was sold for £10,000. . Carnegie, one of the witnesses, says of it: “There were both advantages and disadvantages [in the direct process used prior to Jones's invention], but the disadvantages were so great that we often debated whether to abandon the process or not. We found it impossible to get a uniform quality of rails as well as by the cupola method. . . . When we were
still anxiously struggling with the problem,
The principal features in this invention?
and undecided whether to continue or abandon it, Captain Jones . . . told us that he believed he had invented a plan which would solve the problem. . . . We thought so well of the idea—I was so convinced of its reasonableness—that I directed him to go ahead with his invention. . . . Captain Jones did so, and almost from that day our troubles ended. He had scored a tremendous success; another step forward was taken in the manufacture of steel, and we are using the invention to-day. . . . . . Without this invention I believe that we should have abandoned the mode of running
consist in directing the blast to the body or belly of the furnace, as well as to the hearth thereof, for the purpose of fusing or smelting the entire mass of ore in the furnace simultaneously, or nearly so. . . . The mode hitherto practised in smelting furnaces has been to direct blasts into the hearth only thereof, thereby requiring several hours to smelt or fuse the contents of a large furnace.” The specification is somewhat blind, and it is difficult to see what definite or valuable result is obtained by the use of several small instead of one large furnace, except, perhaps, a quicker
heating and less delay in its practical operations; but it is sufficient for the purposes of this case to say of it that it contains
: direct from the blast furnace. Above al * things, the manufacturer has to regard the * uniformity of * product, , the equality of
rails; and this uniformity cannot be obtained without Jones's invention, as far as I know.” It is true that what is termed the direct rocess was used in connection with the essemer invention in some foreign countries, notably Sweden and France, with more or less success, due to the peculiar character of the ores used in those countries; but such attempts in this country had proven practically failures, and had been abandoned. In regard to this the witness Kennedy said: “The Jones method has made the direct rocess, which was attended with great anger and difficulties before the date of his invention, a thoroughly practicable and successful one. Instead of it being a question of great doubt whether to run the metal direct to the converter or remelt it, as it was up to the time of Jones's invention, no one would now think of building a new works containing both furnaces and converters without arranging to mix the metal by the Jones method, which not only effects an immense saving in the cost of operating the works, but enables a uniformly good product to be made, and also a purer product than can be obtained from cupola metal, which absorbs and is contaminated by sulphur from the coke which constitutes the fuel of the cupola.” Indeed, the value of the process is not wholly denied, though much depreciated, by the defendant, which relies rather upon the fact that it was well known in the art, and that so far as it is described in the Jones specification and drawings it was not infringed by it. 1. We now proceed to an examination of the question of anticipation, in support of which a number of English patents are roduced, which will be briefly considered: #. the British patent to Tabberner of 1856, the object of which was, as stated by the patentee in his specification, “to dispense with the necessity of employing one or more large furnaces, and to use in lieu thereof several small furnaces, the combined capacities whereof are equal to that of one or more large furnaces, and to cause these small furnaces to discharge their contents at short intervals of time into one large reservoir, from which the molten metal may be drawn for casting from. . . .
no suggestion of a mixing of different casts for the purpose of obtaining a more uniform product, and that the invention has no relation to a further treatment or refining. It does contemplate the use of a reservoir, but there is no suggestion of a reservation in such reservoir, of a quantity of molten metal. It is not denied that the use of a reservoir from which molten metal may be drawn long antedated the Jones patent. But the best that can be said of the Tabberner patent is that, if the reservoir had been of sufficient size and properly constructed so as to never be completely emptied, it might have been adapted to carry out the Jones process; but there is no evidence that it was ever so constructed, or that the production of a uniform discharge from the reservoir was contemplated. That it could not have been intended for the purpose of carrying out the Bessemer process, or any other process, for the use of blast-furnace metal in a converter, is evident from the fact that the patent was nearly simultaneous with the Bessemer patent, of the existence of which the patentee appears to have been entirely ignorant. The English patent to Deighton of 1873, for “improvements in the arrangement and mode of working an apparatus for the manufacture of Bessemer steel,” contains the closest approximation to the principle of the Jones invention. If this does not anticipate, none does. The primary object of the E.; seems to have been to prevent the loss of time while the converters area being cooled and relined or repaired, and: again" prepared for work, by providing that's the converting vessel shall be so arranged that it can be readily detached from its actuating mechanism and lifted bodily out of its bearings by a suitable crane or other lifting mechanism, and a spare converter substituted in its place. There is, however, a further provision in the patent, as follows: “Instead of manufacturing Bessemer iron or steel from pig iron, which has been melted in cupolas, my invention also consists in taking the molten metal directly from the blast furnace to the converter, in which case I prefer to arrange the Bessemer plant in a line at a right angle to a row of two or more blast furnaces, and place a vessel to
receive the molten metal tapped from two or more blast furnaces to get a better average of metal which will be more suitable for making Bessemer steel or metal of uniform quality, the vessel or receiver being placed on a weighing machine so that any required weight may be drawn or tapped from it and charged into the converter.’ The +.” provide for manufacturing Bessemer steel directly from the smelting furnace by employing gates or channels for molten metal from each furnace, leading to a reservoir, which is placed low enough to give fall for the molten metal to flow from the blast furnace to this reservoir, which forms a receptacle for mixing the molten metal from two or more of the smelting furnaces. From the reservoir the mixed molten metal is tapped, and flows down the swivel trough into the converter. By placing the reservoir on a weighing machine, it can be readily ascertained when the exact quantity required has been tapped from it into the converter. The sixth claim of the patent is for “the system or mode of arranging and working Bessemer converters with a receiver or receptacle for mixing the molten metal from two or more smelting furnaces to get a more uniform !. of metal, substantially as hereinbeore described and illustrated by the draw
While Deighton seems to have conceived the idea that uniformity of product was necessary to the successful use of the direct process, and might be attained by mixing the discharge from several blast furnaces * in an open reservoir, standing between the furnaces and the converter, the dominant idea of the Jones invention, that a constant quantity of molten iron should always be kept in such reservoir to serve as a basis for such mixture and an equalizer of the different discharges, does not seem to have occurred to him. As the discharge pipe was located at the bottom of the reservoir, it was certainly possible to empty it entirely, and the testimony in the case indicates that this was the natural method of operation. If this were so, then the reservoir accomplished nothing beyond the mixing of each batch of metal introduced into it from the different blast furnaces. There is nowhere in the specification a suggestion of supplying to and withdrawing from the reservoir small amounts at a time, a constant quantity of metal being retained, in the reservoir for the purpose of “...; the different products of the blast furnaces. While the Deighton reservoir, if a cover had been added to it, might perhaps have been utilized for that purpose, there is no evidence that such use ever occurred to the inventor. Indeed, the absence of a cover to the reservoir is evidence, even to a nonexpert, that it was not contemplated that a ermanent, quantity of molten iron should É. retained in it, since a radiation of heat would thereby be produced and the contents skulled or crusted over with a layer of refuse iron or slag. The testimony is clear that the Jones process cannot be carried on in an open reservoir, and the ab
22 S. C.—45.
sence of a cover is conclusive that it is not so used. It is insisted, however, that defendants have demonstrated, by practical experimentation with a plant constructed according to the specification of the Deighton patent, that the results are practically the same as those obtained by the Jones process. This plant, however, was constructed after suit brought, long after the Deighton patent had been allowed to expire, and with no opportunity afforded the plaintiffs to inspect the plant, or witness its operation. The tank was fitted with a cover, and a constant pool of molten metal retained in it; but this was not the Deighton process, but the Jones process adapted to the Deighton device. Were this evidence admissible at all, we are satisfied that it is met by the fact that if the Deighton patent had been : adaptable to the Jones process, it is scarcely , possible" that its merits should have failed * to seize upon the attention of manufacturers, who would have brought the patent into general use, instead of allowing it to lapse for the nonpayment of a comparatively small fee. As something in the nature of the Jones process was needed to enable steel to be manufactured directly from the product of blast furnaces, the utility of the Deighton patent for .P.": would at once have been recogni and its success assured. But evidently that patent was not the final step in the accomplishment of the mixing process. It contributed nothing to the art of manufacturing steel, and, although issued in 1873, was allowed to lapse in 1876, after an apparently unprofit; able existence for three years, by reason of the nonpayment of the stamp duty, necessary to keep it alive. It is sufficient to say of it that it fails to disclose, fully and precisely, the essential features of the process covered by the Jones patent. Walker, Patents, $ 54; Seymour v. Osborne, ll Wall. 510, 555, 20 L. ed. 33, 42; Illinois C. R. Co. v. Turrill, 94 U. S. 704, 24 L. ed. 241. Although Deighton was an employee of the Moss Bay Company of Workington, England, if any attempt were made by this company to make use of his process, it evidently amounted to nothing, since one of the writers, Snelus, contributing to the Journal of the Iron and Steel Institute, 1876, says: “One great drawback to the direct casting process was that you could not always get your metal at the exact time you wanted it. He believed that it would be found that the great advantage the Bessemer works in America had was the intermediate receiving ladle, which was designed by Mr. Holley, and which was universally used there, although it was never used in England. The Moss Bay Company attempted to modify the thing some time ago, and put up a heating furnace; but that, to his mind, was a step in the wrong direction. Anyhow, the thing had failed, and no one in England, so far as he knew, was using any intermediate receiver between the blast furnace and the converters.” This defense presents the common in
stance of a patent which attracted no attention, and was commercially a failure, being set up as an anticipation of a subsequent patent which has proved a success, because there appears to be in the mechanism" described a possibility of its having been, with some alterations, adaptable to the process thereafter discovered. "As hereinafter observed, a process patent can only be anticipated by a similar process. It is not sufficient to show a piece of mechanism by which the process might have been performed. In the American patents to Durfee, Nos. 118,597 and 122,312, both of 1871, the desirableness of manufacturing steel directly from the blast furnace is recognized, and in his second patent he says: “That in the manufacture of steel by the pneumatic or Bessemer process a great saving of fuel and iron, of wear and tear of furnaces, and of labor, would be effected were it possible to make uniformly good products of the desired temper by converting the crude iron immediately it is tapped from the blast furnace in which it is made. This plan has been and may still be practised to a considerable extent, but it has been found that, by reason of the irregular working of blast furnaces and the consequent varying character and quality of the crude iron produced, it was always very difficult and in most cases impossible to secure such uniformity in the converted metal as was essential to success in the business. Hence, at several establishments where the plan of taking the fluid iron as it was tapped from the blast furnace, and pouring it at once into the converter, had been practised, it has been abandoned, the Pop'. preferring to incur the expense of handling and remelting the crude iron after it had been cast into pigs, in order thus to secure the advantage of carefully selecting and mixing the materials for each charae to be convert
duct of the blast furnace. This metal is .# cast in the form of pigs, then remelted in the cupola as needed, before being charged into the converter. - It is very desirable to take advantage of the molten condition of the metal as it comes from the blast furnace for its use in the converter, because thereby the remelting of the metal and the expense of the construction of a cupola may be avoided. The charge of the converter is from one to five tons, and the casting of a blast furnace runs usually from ten to fifty tons. The difficulty of using the molten metal from the furnace to the converter consists in keeping the large quantity of metal from the latter in a proper molten condition for use in the former.” He proposed to remedy this by a reservoir provided with a suitable cover and with tuyeres “which blow down upon the surface of the metal for the purpose of maintaining its heat and fluidity.” As this reservoir was apparently adapted to hold a single cast, and therefore must be emptied before another cast was received into it, it was impossible that Witherow intended by its use to practise the Jones process. There is no suggestion anywhere in the patent of a desire to retain a quantity of metal in the reservoir to serve as a basis for mixing the various products of the blast furnace, which was the dominant idea of the Jones patent. To anticipate a process patent, it is necessary not only to show that the prior patent might have been used to carry out the process, but that such use was contemplated, or that the leading idea of the Jones patent of maintaining a dominant so in the reservoir was such a use of the Witherow patents as would have occurred to an ordinary mechanic in operating his device. Wheth: er the reservoir in the Witherow patent was partly or fully emptied seems to have been a matter of complete indifference to
the inventor, and the idea of maintaining: a constant quantity therein seems to have: ["never been conceived by him. His design"
ed.” He proposed to accomplish this by using a reverbatory gas furnace, into which the
crude iron from the blast furnace is poured, and in which it may be mixed with other irons, and so treated as to insure uniformity. Pig iron of different qualities, or any metals or metalloids or fluxes, can be added and mixed with the metal as may be necessary to bring it to the required character. The process is so manifestly different from that described by Jones that it demands no further attention. If it were put in practice at all, it seems to have proved a failure, as, although an English atent was taken out by Durfee, it was alowed to lapse by reason of the nonpayment of the stamp duty. *Two American patents to James P. Witherow, No. 315,587 and No. 327,425, both issued in 1885, are pressed upon our attention. In the second patent, the only one necessary to notice, he restates the advantages of the direct process and the difficulties theretofore encountered in its practical operation. “In the manufacture of steel by the pneumatic process, the converters are charged with molten metal, the pro
seems to have been merely to provide a reservoir for the storage of the large quantity of metal from the blast furnaces, and to maintain its heat until the comparatively small quantities required in the converters had been drawn off for use. As he states in his specification: “The metal is usually tapped from a blast furnace once in every six hours, and the quantity thus cast is many times in excess of the charge of a converter,” which “is from one to five tons,” while “the cast of a blast furnace runs usually from ten to fifty tons.”. While the metal is tapped from the blast furnace once in every six hours, “the time between charges in the converter is usually twenty minutes and upwards, and the metal in the furnace must be kept in condition to be tapped from time to time into the converter as needed.” This appears to have been the whole object of the invention. The same remark may be made of all these prior devices. While all contemplate the reservoir between the blast furnaces and the converters, such reservoir is used for