Hagan v. Swindell

• Decision Date: 04 April 1913
• Docket Number: 1,700.
• Parties: HAGAN v. SWINDELL et al.
• Court: U.S. Court of Appeals — Third Circuit

204 F. 442

HAGAN v. SWINDELL et al.

No. 1,700.

United States Court of Appeals, Third Circuit.

April 4, 1913

Appeal from the District Court of the United States for the Western District of Pennsylvania; Charles P. Orr, Judge.

Suit in equity by Edward H. Swindell and Bessie Swindell, as executors of William Swindell, deceased, and John C Swindell, against George J. Hagan. Decree for plaintiffs, and defendant appeals. Affirmed.

For opinion below, see 198 F. 490.

PATENTS (s 328*)-- VALIDITY AND INFRINGEMENT-- ANNEALING FURNACE.

The Swindell patent, No. 624,4018 for an annealing furnace, in which gas is used as the fuel, especially adapted to the annealing of metal sheets, covers a combination which is novel and discloses invention. The invention is also important and valuable, and the patent is entitled to a reasonable range of equivalents; also held infringed.

Harry Easton, of Pittsburgh, Pa. (F. H. Bowersock, of New York City, of counsel), for appellant.

G. H Parmelee and Clarence P. Byrnes, both of Pittsburgh, Pa., for appellees.

Before GRAY, BUFFINGTON, and McPHERSON, Circuit Judges.

J. B McPHERSON, Circuit Judge.

We do not agree with the appellant's criticism of Judge Orr's opinion reported in 198 F. 490; but there may perhaps, be some advantage in explaining the patent a little more fully. In doing so we shall take the liberty of making free use of the appellees' brief.

It should first be observed that, while the claims refer to 'a furnace,' it is manifest from the specification and the drawings that a particular class of furnace-- namely, an annealing furnace-- was especially the object of the inventors. The specification says so repeatedly, and, as this controversy is between two annealing furnaces, it is not necessary to decide whether the claims are to be so construed as to embrace a furnace built for another purpose. So far as appears, also, both furnaces are built and used for the sole purpose of annealing metal sheets or plates with gas fuel. Now, a furnace to anneal metal sheets must be specially built and operated. The floor must support and resist very heavy loads and strains, as the charges often weigh as much as 40 tons, and sometimes twice as much. The boxes with their contents are arranged in a row, parallel with the sides, and the prime object is to subject every box, surface and contents, to the same uniform heat. Otherwise, some sheets may be burnt by overheating, and some may be underheated, so as to require reannealing. It is desirable to preheat the air that is fed in to assist combustion; for preheating promotes a higher temperature, and is an important factor in economy and a larger output. In the process of annealing, the boxes and sheets are raised to a red heat, and then gradually cooled down; the time needed being 12 to 20 hours. Before the Swindells entered the field with the patented device, annealing furnaces were not satisfactory; they were of old designs, and were ordinarily heated by a coal fire. They were all of the same type; the gases of combustion passed through the furnace from end to end, passing over the boxes in a similar direction, namely, in tandem, one result being that the heat was greater near the firebox than at the farther end. Obviously, there was continual danger either that the first boxes would be overheated, or that the last boxes would not be heated sufficiently and would need to be reannealed. It was difficult also to anneal the contents of each box uniformly; either the top sheets were in danger of being burned, or the lower sheets were in danger of being underheated. These troubles happened, whether the heat came from coal or from gas. The boxes were short-lived, the output was relatively small, and, as the air was not preheated, more time and more fuel were needed to obtain the proper temperature. With these disadvantages to overcome, the furnace of the patent was devised, and a remarkable success followed speedily.

We shall quote the specification in a few moments, but a brief description of what the invention has accomplished may precede the quotation. In the furnace of the patent, uniform heating for every box and uniform annealing for its contents have practically been secured. Instead of the old tandem arrangement, the boxes are now placed between a row of inlet ports for gas and air, respectively, on one side of the combustion chamber, and a row of waste ports on the other. When the gas and the air are ignited, a sheet of flame equally distant everywhere from the row of boxes envelops them all, top, bottom, and each side, and finally leaves the chamber through the waste ports in the floor on the opposite side. The ports for gas and air are vertical, arranged along one side of the furnace at some distance above the floor; air and gas alternating so as to mix readily and burn to advantage. By raising the ports for gas and air above the floor, the flame does not short-circuit, but normally divides, and thus passes both above and below each box to the waste ports, heating the box uniformly during the passage.

Another advantage is obtained by the way in which the air is preheated. While preheating air is not new, the patentees were the first to apply the idea to annealing furnaces. By a simple and efficient arrangement of flues they were able to preheat the air, and also to take care of the great weight of the boxes. The boxes, sheets, and thick metal slabs or bottoms are very heavy, and, in order to support the weight and meet the strain of charging and discharging, the old annealing furnaces ordinarily had a solid floor and foundation. But the patentees solved the problems of support and of preheating by building longitudinal flues in the floor structure, each flue being parallel with the ports for air and gas, with the boxes, and with the waste or outlet ports. Of these flues one supplies air, and its roof is the hot floor of the combustion chamber. Another supplies hot producer gas to the gas ports; and this flue runs along and just within the side wall. The third is the hot waste flue connecting with the waste ports in the floor. It will be seen that by this construction the longitudinal walls between these parallel flues furnish strong and continuous piers to carry the boxes and to resist the...