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Statement of the Case.

ment] furnaces the slag is driven out [of the furnace] by first being [being first] forced below the tymp stone, which projects below the level of the tuyeres and intercepts the currents of air and prevents their escape with the slag which stands in the [tymp] fore hearth at the same level as on the hearth, the slag being discharged only when it rises in the [tymp] fore hearth high enough to overflow the top of the wall stone that forms the bottom of the discharging orifice. By this arrangement the tymp stone constitutes a trap which intercepts the currents of air and causes their pressure to be exerted directly on the surface of the slag on the hearth. This method of construction has several disadvantages, one of which is the difficulty of keeping the tymp stone and the surrounding parts in repair; another is, that the pressure of the currents of air or wind is limited [and counteracted] by the counter-pressure of the column of slag in the [tymp] fore hearth; and another is that, one side of the furnace being occupied by the [tymp,] fore hearth, no tuyere can be applied on that side, and consequently the supply of wind is irregularly distributed. By the improvement which constitutes the subject-matter of this present invention these disadvantages are overcome [My invention avoids or overcomes these disadvantages] in a simple and effective manner.

"In [this example of my invention] the drawings the letter A designates the furnace, and B several tuyeres, which are arranged therein at a proper height. The furnace is constructed with a closed breast, [My furnace has no tymp] and the sides of the hearth, whether round or square, extend clear down to the bottom stone, the usual opening, (not shown in the drawing,) being made in the lower part of the hearth for the discharge of the iron. The openings for the tuyeres B are distributed at equal distances apart in the sides of the hearth. At a suitable height from the bottom stone [I leave] an opening is left in the hearth, in which [I place] is placed a cast-iron or brass slag-discharge piece or cinder block, D, which is cast or made with numerous channels or pipes running up and down or in other directions through it, as shown in Figs. 3 and 4. The cinder block [piece] D [is] may be

Statement of the Case.

formed with a dovetail on its upper end, which is fitted into the bottom of a stationary metallic plate, C, connected with the furnace, or it may be attached to said plate in any other desirable manner, or cast solid with the same, if desired. [The] This plate [C] is also cast or made with channels or pipes running through it, and the channels or pipes of said plate and of the cinder block [piece] D may be so arranged as to connect or communicate with each other when the plate C and cinder block [piece] D are in their proper position, [positions] or they may be independent of each other. In the drawing the plate C is shown above the cinder block, but it may also be placed below or in any other desirable position in relation to the same. The object of the [said] channels or pipes is to permit the plate C and cinder block [piece] D to be cooled by forcing water through them while the furnace is in operation, proper connections being made for that purpose with a reservoir of cold water or with a force-pump. One or more holes are made in the [said piece] cinder block D, through which the slag is discharged, the shape of said holes being shown in Figs. 3 and 4, the middle portion being cylindrical, but each end being conical or flaring. The dimensions of the [slag-discharge piece] cinder block are a little less than the opening in which it is placed and the space left around it is filled with sand, which can be readily removed in case it is desired to remove the block D to repair it or if it is desired to have an opening in the hearth to work through, as when any. irregularity in the smelting process has taken place. The flow of the cooling water through the [slag-discharge piece] cinder block D is regulated for the purpose of controlling the discharge of the slag through it. By allowing much cooling water to circulate through its water channels or pipes, the temperature of the block [piece] D is lowered sufficiently to allow a coating of slag to adhere and choke its discharge openings, which are of less diameter in the middle than at their ends. By reducing the flow of cooling water the cinder block [piece] is allowed to retain a higher temperature, and in consequence the slag is melted out of the discharge openings and they become clear and open and permit the slag to flow

Statement of the Case.

without interruption. When the slag in the hearth is [lower than] below the level of the discharge openings the latter are simply closed by an iron plug [rod]. [My] This invention. can be easily applied by those skilled in the art to which it belongs, to blast furnaces of the common construction, by removing the fore hearth and closing the aperture left in the breast of the furnace under the tymp stone by inserting the plate C with the cinder block D. [This invention is attended with several advantages over the common method of constructing or arranging furnaces, among which I mention the following:] The principal advantages derived from this invention are as follows: First, it permits a higher pressure of wind. Second, the hearth is preserved in better condition than where the common mode of construction is retained. Third, the labor of the operation of smelting is lessened. Fourth, it allows one more side of the hearth for a tuyere. Fifth, it avoids the stoppages of the wind supply now necessary as often as the iron is discharged. Sixth, a considerable increase is gained in the product of the furnace, while at the same time the cost of labor and repairs is lessened.

"Having thus described this invention, [What] what I claim as new, and desire to secure by letters patent, is —

"1. A blast furnace with a closed breast, where the slag is discharged through an opening or openings cooled by water, substantially as set forth.

"[1] 2. The slag-discharge piece or cinder block D, constructed and arranged substantially as described.

"[2] 3. The [slag-discharge piece] cinder block D, in combination with the plate C, to which it is fitted [attached,] substantially as described.

"[3.] 4. The shape of the discharge opening or openings of the cinder block [piece] D, being made flaring at its ends, and of diminished diameter in the middle or central part, substantially as described.

"[4.] 5. The combining [Combining with] of the slag-discharge piece or cinder block with a series of water channels. or pipes, substantially as and for the purpose above set forth.

Argument for Appellee.

"[5.] 6. Combining with the metallic plate C a series of water channels or pipes, substantially as and for the purpose

set forth.

"[6.] 7. The method of controlling the discharge of slag from blast furnaces by regulating the temperature of the slagdischarge piece or cinder block, substantially as described. "This specification signed by me this [twelfth day of July, 1867,] 24th day of October, 1868.

"[F. W. LURMANN.] George Asmus.”

After a hearing on pleadings and proofs; the court entered a decree, on the 19th of July, 1886, adjudging that the reissued patent was valid; that the defendant had infringed its first claim; and that the plaintiff was entitled to recover profits and damages, and referring it to a master to ascertain the same. The opinion of the Circuit Court was given May 14, 1886, and is reported in 27 Fed. Rep. 684. On the report of the master, a final decree was made by the court October 12, 1888, awarding to the plaintiff $1000 damages and the costs of suit. The defendant has appealed to this court.

Mr. William D. Baldwin for appellant. MacVeagh was with him on the brief.

Mr. Wayne

Mr. William Bakewell and Mr. Thomas B. Kerr for ap pellee.

The validity of the patent in suit is contested on the grounds that the original patent was not surrendered for good and lawful cause; that the reissue, as granted, is not for the same invention "which was specified in the said original letters patent," but, on the contrary, was obtained on the application of an assignee, without the knowledge or consent of the inventor, for the purpose of expanding or enlarging the claims, so as to cover another and different invention from that described and claimed in the original letters patent, and that the reissue was unlawfully and unwarrantably expanded and enlarged to cover inventions other and different from and broader than those de

Argument for Appellee.

scribed and claimed in said original letters patent, and that said reissued letters patent are therefore void.

In the cases on reissue, especially those decided by this court, it will be found that it is not the mere fact of reissue, or of a change in the specification or in the claims, which is the cause of the trouble. There is always something else which renders such changes improper, as, for example, that the patentee has slept on his rights and allowed an undue time to elapse after the grant of the original patent before applying for reissue, the reasonable time being usually two years in analogy to the right an inventor has to use his invention publicly for that length of time before completing his application; or that the purpose of the reissue is merely to expand the claims beyond the scope of the described invention; or that it was made in order to claim that for which the applicant was refused a patent by the patent office, withdrawing the claim in order to obtain his patent; or to introduce into the specification. some new suggestion of invention and base a claim upon it, or to claim a patent for that which was not claimed in the original. In these cases reissues are held to be invalid.

None of these adverse circumstances exist in this case. We start with the following facts: (1) That the specification and drawings of the reissue are substantially the same as the original patent. This appellant's expert admits: (2) That the only claim in which a decree is asked in favor of the appellee (the first) is for an invention which is (a) clearly and fully described in the original specification: (b) distinctly stated in the original specification to be the invention of the applicant: (e) manifestly the same which the original patent states to be the gist of the invention: (3) That the application was made within one year after the date of the original patent: (4) That there is no evidence that the invention was used by the public between the dates of the original and the reissue so that no adverse rights have accrued.

An objection to the reissue is made in the answer that it was obtained on an application of an assignee and without the knowledge or consent of the inventor. A sufficient reply to this is that the reissue was granted under the act of 1836,

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