F.

Report of C. M. Keller, Examiner, &c.

PATENT OFFICE, January 25, 1845.

SIR In conformity with your wishes, I have the honor to submit the following report on the progress of inventions during the past year. The classes of inventions intrusted to my charge, as examiner, are 1st. Metallurgy, and manufacture of metals.

2d. Manufacture of fibrous and textile substances.

3d. Steam and gas engines.

4th. Navigation and marine implements.

5th. Civil engineering and architecture.

6th. Land conveyance.

7th. All kinds of mills for grinding grain, &c.

8th. Machinery for working lumber.

9th. Fire arms and implements of war.

10th. Miscellaneous.

In the report which I had the honor of submitting to your consideration last year, I gave a hasty sketch of the progress of inventions in the above classes up to that time, commencing with the infancy of the mechanic arts in the United States; and, although very hasty, it was sufficient to show the rapid strides with which we have reached an early and distinguished maturity.

In this report, as in the preceding, I shall not strictly confine myself to the inventions of the United States, but introduce such of the inventions of Europe, which have come to my notice, as I may deem worthy of public attention, either in their immediate applicability to our industry, or as containing the germs of future usefulness; for it often occurs that ideas which, in themselves, possess no practical usefulness, suggest and lead to the most important and useful inventions.

1.—METALLURGY, AND MANUFACTURE OF METALS.

At the time the gold mines of the South were first worked, ingenuity was stimulated to improve the processes and apparatus employed in the separation of the metal from the accompanying impurities, and many patents were obtained about that period. But the want of success in the working of many of these mines checked this stimulus; and within the past year not one invention made in this country, and but one introduced from abroad, has been patented; and as this appears to be important, I deem it advisable to point out its main features.

Heretofore, in separating gold from the impurities, by the process of washing, it has been subjected to only one current of water, either vertical or horizontal-the object being to carry away the impurities that are of less specific gravity than the metal, and leave it behind; but the process in question subjects it to the combined action of two currents of water-one vertical, and the other horizontal; the former carrying the impurities above the level of the metallic particles, and the latter washing them away, by which the process is greatly expedited. The apparatus for applying this process consists of a series of sieves separated by partitions, and surrounded by a casing with a valve opening upwards, and placed at one end of the series. The materials to be washed and separated are dropped into the first sieve of the series from the hopper above, adapted to

[ 75 ] the delivery in given quantities, and the sieves then receive a vertical reciprocating movement in a water tank. On the descent of the sieves, the water passes through the meshes of the sieves and the valve; the former producing the vertical current, loosening the lighter and impure particles, and carrying them above the partitions; and the latter, by its volume, the horizontal current, washing all that has been carried above the partitions to the next sieve, and so on to the end of the series, to catch the particles of gold that may have been carried up with the impurities.

Nothing of importance has passed under my notice during the past year, originating either in Europe or in this country, connected with that branch of metallurgy devoted to the obtaining of metals, except in iron; the working of which becomes of more importance every day, from the great wants of society, and the rivalship of capital, industry, and ingenuity, invested and devoted to this highly important branch of the arts.

In my last report I alluded to the important results brought about by the use of the gases escaping from smelting and other furnaces, as a fuel, by the admixture of these with atmospheric air. A modification of this important invention was patented in the latter part of the year 1842; and as it has since been reduced to successful practice, I deem it important to the iron interests to call public attention to it. The improvement is applicable to all reverberatory furnaces, and is intended to remove defects which have been known to exist ever since the rationale of the process was understood. When a fresh charge of coal is put on the grate, a large portion of the heat becomes latent, in gasefying the coal, preparatory to its ignition; which gases, thus evolved, are mostly combustible, and, not being supplied with oxygen, escape from the chimney in an unconsumed state-thus wasting great quantities of fuel; and when the gases have been distilled, and the coal is in an incandescent state on the bars, the blast supplies too much oxygen, which, coming in contact with the iron, oxidizes and wastes it. To remove these difficulties, the fire chamber of reverberatory furnaces is made of such depth as to have a very thick stratum of coal upon the grate, which fuel is converted into combustible gases by a blast, or current of air, forced into a closed ash pit under the grate; and in combining with this gas-generating chamber and furnace an arrangement of blow-pipes, or other convenient apparatus, through which heated atmospheric air is to be forced, by means of any ordinary blowing machine, into the said gases, for the purpose of effecting their combustion in passing to the chamber of the furnace containing the iron where the heat is to be applied. In this way, all the gases, instead of escaping as heretofore, are consumed in the immediate neighborhood of the iron where the heat is required, and the oxygen of the atmospheric air is not permitted to act injuriously upon the iron whilst heating it.

The following extract from the Transactions of the Society of Arts may be worthy of the attention of our ironmasters:

"Improvements in the manufacture of iron.-Patented by Thomas W. Booker, Esq., of Melin Griffith, near Cardiff.

"The method usually, now and heretofore, adopted in the manufacture of bar iron, (where the dangerous, and, as the author thinks, reprehensible practice of puddling the crude or raw pig iron, without the intervention of the refining process, is not adopted,) is as follows: The pig iron is

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thrown upon what is called the milling finery, or run into the finery in a fluid state from the smelting or blast furnace; and, after undergoing the process of refining, it is run out into cakes or moulds, and suffered to get cold; it is then broken up into lumps of a convenient size, and thrown into the puddling reverberatory furnace, which is usually constructed with one door, and at which only one man can work at a time. The author's improved method is detailed in his specification, plan, and model, and the effect is this a saving of fifty per cent. in fuel, and nearly 50 per cent. in metal, an immense saving of labor, and a greatly increased product of work in the puddling furnace: the usual product of a puddling furnace being from fourteen to eighteen tons in a week, while the author's will as easily produce from forty to fifty tons in a week. The author thus combines the process of refining with puddling; and, to show the importance of preserving, and the hazard of dispensing with the refining process, he subjoins the results of an analysis by M. Berthier, of three samples of cinder or scoria, in one of which the remarkable fact of the presence of phosphoric acid shows how important this operation is to the purification of the iron.

"The object of Mr. Booker's invention is to simplify and accelerate the conversion of cast iron from its crude state into malleable or wrought iron; for which purpose, the refinery furnace is adapted to the various qualities or descriptions of cast or pig iron which it may be necessary to use, by surrounding or enclosing the earth with blocks of cast iron, into and through which water is allowed to flow out, or not, as may be expedient; and, as is well understood in making refinery furnaces, the blast of air being introduced through one, two, or more apertures or tuyeres, as usual.

"The refining is connected with the reverberatory or puddling furnace, which is constructed of the requisite form and dimensions. The bottom of the body of the furnace, and the grate bars, and binding plates and bars, are formed of iron; the other parts of the furnace are constructed with fire bricks, sandstone, or fire clay, as is well understood. In the neck, or near the flue of the reverberatory furnace, is an aperture through which the iron, when it has become decarburetted or refined in the refinery, is introduced, or run in a fluid state, direct from the refining hearth into the puddling or reverberatory furnace. On each side of which reverberatory furnace a door is constructed; the door in the one side being immediately opposite to the door in the other; through which two doors the workmen perform the process of puddling, in the ordinary way in which puddling is done when working only with one door, which is the general practice. "As respects the refining.-Having thrown up the fuel, and having, by the application of fire and blast, produced the necessary heat, a charge of 9 ew, or thereabouts, of pig or cast iron, of the description generally used for forge purposes, is thrown on and melted down, and decarburetted or refined in the ordinary way; and when the refining process is completed, the whole charge of metal is run off in a fluid state direct into the reverberatory or puddling furnace, previously prepared to receive it, by

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having been already heated to a proper degree of temperature, and by the bottom, sides, bridge, and opening to the flue, being protected in the ordinary way, by the workmen having previously thrown in a sufficient quantity of limestone and iron cinder. The metal having been introduced into the reverberatory or puddling furnace in a fluid state, the workmen raise, apply, and regulate, and vary the heat in the ordinary way, by feeding and moving the fire in the grate, and raising or lowering the damper on the top of the stack or flue, as circumstances require, and as is well understood; they at the same time stir and agitate the iron with bars and puddles, while the escape of the oxide of carbon, in a gaseous shape, takes place, and until the whole mass of iron agglutinates. The workmen then divide it into lumps or balls of a convenient size, and draw the charge from the furnace, passing the lumps to the squeezer, hammer, or rolling cylinders, or such other contrivance or machinery as is used for forging or compressing the iron.

"During the process of refining the iron, by the application of heat and blast, in the open refining hearth, a considerable quantity of scoria or cinder is produced, which is tapped and run off as heretofore, as circumstances require. But it is to be observed that, during the process which the iron undergoes in the reverberatory or puddling furnace, the author does not find that any cinder need be generated or produced; and cinders and limestones are thrown in, as already described, for the protection of the various parts of the furnace exposed to the action or agitation of the fluid metal, but no cinder need be tapped or drawn off.

"Mr. Aiken's opinion. The principal novelty in Mr. Booker's invention consists in placing the refinery and puddling furnace so near each other, that the refined iron may be run in a liquid state into the puddling furnace, instead of allowing it (as is usual) to cool and become solid when let out of the refinery, previous to its being transferred to the puddling furnace. The heat lost by the iron is thus saved, as well as the time required to bring the solid refined iron to a state of fusion. Both the refining and puddling are to be performed, according to Mr. Booker, in the usual way; it was therefore incumbent on him to show how it happens that, while the common process of puddling produces slag, his does not.

"Mr. Booker's statement, that by his process a saving of full 50 per cent. in fuel, and nearly 50 per cent. in metal, is effected, appears to be an enormous exaggeration; the saving in the former being only (as far as appears) the fuel required to melt the refined iron. In making iron of the best quality, 31.74 cwt. of pig iron give 26.45 refined, which is reduced to 23 in the puddling process; 8.74, therefore, is the loss which 31.74 pig suffers in becoming puddled iron. Half this loss (namely, 4.37) will represent 50 per cent. of saving; and this, added to 23, makes 27.37, which is 0.92 more than the entire quantity of refined iron.

"Berthier's analysis of two samples of scoriæ from South Wales, and one from Staffordshire, showing the presence of phosphoric acid in the former, and none in the latter, has no bearing on Mr. Booker's statement that, in the process of refining, the phosphoric acid is separated from the iron.

"If the quality of the iron produced by Mr. Booker's process is not worse than that of iron refined and puddled in the usual method, Mr. B.'s process deserves the approbation of the society. But I would recommend that Sir J. Guest, or some other practical ironmaster, should be consulted.

"In answer to a communication from the secretary, Mr. Booker writes: "I account for the production of slag in the common puddling furnace, and its non-production in mine, as follows: The common puddling furnace is so constructed, that the iron operated upon in it is exposed to a very rapid draught or current of air, which rushes in at the grate at the back of the furnace, and passes off through the body, and into the flue and stack at the head thereof. This draught is so great as to oxidize the iron, and transform a great portion of it into slag or scoria, during the process of puddling; which process, moreover, is effected so slowly, that the charge of iron, consisting of from 34 cwt. to 44 cwt., is exposed to the heat and draughts in the puddling furnace during the space of full an hour and a half.

"My puddling furnace is so constructed, that the draught or current of air admitted at the grate is broken, and its oxidizing effects upon the surface of the iron while fluid, and upon the fibrous particles as they cohere, after the oxide of carbon has been expelled, are entirely neutralized. That portion, therefore, of the charge which, in the common puddling furnace, is converted into slag or cinder, in mine is not wasted or oxidized, but remains and is converted into pure malleable iron.

"The saving of fuel is thus accounted for: In the common puddling furnace, not more than 4 cwt. is admitted at one time, and this in a solid cold state. In mine, double the quantity is admitted, and that in a melted and fluid state. It is obvious that the time, fuel, and labor necessary for melting the iron are saved, and that double the quantity of iron is converted from a cast into a malleable state within half the space of time.""

The manufacture of malleable iron directly from the ore continues, and will continue, to attract the attention of the ironmaster, until all the diffi culties to its economical application shall have been surmounted, and science and art shall be able to claim this as another triumph. Within the past year, a patent was granted having this important object in view; and, to satisfy the iron interests, I here insert the description of the process given by the patentee, without meaning to be understood as approv ing or disapproving the suggestions of the inventor; which, as I have not heard of the practical test, might prejudice the inventor or the public.

The patentee proposes to carry on his process in puddling furnaces so modified in form, by elevating the roof towards the chimney, as to avoid the reverberatory character, and thus prevent the flame from impinging on the ore, which (says the patentee) "converts the larger part of it into slag, instead of reducing it into malleable iron." The ores, instead of being mixed with fluxes, in the usual manner, which has always been considered indispensable, are to be employed alone, by mixing together, in due proportion, such ores as by their chemical composition are calculated to react upon each other when duly heated, and to bring the metal contained in each of them into the malleable state-such as oxides and carburets of iron; the oxygen of the former uniting with the carbon of the latter, will, in the judgment of the patentee, liberate the particles of iron, which, when brought to the proper degree of heat, are to be balled in the usual manner of puddling.

and,

Such are the views of the inventor, as given in his specification; in introducing them, I do not wish to be understood as approving or disapproving them.