Stewart-Warner Corp. v. Lone Star Gas Co.

• Decision Date: 10 June 1952
• Docket Number: No. 13478.,13478.
• Citation: 195 F.2d 645
• Parties: STEWART-WARNER CORP. v. LONE STAR GAS CO. et al.
• Court: U.S. Court of Appeals — Fifth Circuit

195 F.2d 645 (1952)

STEWART-WARNER CORP. v. LONE STAR GAS CO. et al.

No. 13478.

United States Court of Appeals Fifth Circuit.

April 3, 1952.

Rehearing Denied June 10, 1952.

Casper W. Ooms, Benjamin F. Wupper, and Warren C. Horton, all of Chicago, Ill., J. A. Gooch, Fort Worth, Tex., for appellant.

M. Mallet-Prevost, Washington, D. C., Claude Williams, Marshall Newcomb, Archie D. Kroney, all of Dallas, Tex., for appellees.

Before HOLMES, RUSSELL and RIVES, Circuit Judges.

RIVES, Circuit Judge.

This is a suit for infringement of U. S. Patent No. 2,087,983, issued July 27, 1937 to J. Woodward Martin, and covering a device described as a "Draft Equalizer for Gas Burners." The district court held the patent valid and infringed and enjoined appellant from the further manufacture and sale of its "Saf-Aire" gas heater.

The evidence involves the gas-burner art, and particularly the problem of taking from out-of-doors the fresh air necessary to operate such a burner, and discharging into the outside atmosphere the combustion gas from the burner, without allowing the gas flame to become adversely affected by action of the wind, or "reversals of draft". In heating plants burning gas or oil, reversal of draft has through the years posed a serious problem, since a gust of air entering the firebox in the wrong direction may extinguish the flame and pilot light. When that happens, the fire will not start again when the draft returns to normal. Instead, the burner jets may discharge unburned gas into the firebox and thus create a dangerous and explosive condition. The importance of avoiding draft reversals in gas burners has been understood by heating engineers for many years, and every safe gas burning device must necessarily incorporate some safe and effective means for preventing draft reversals.

One attempted solution to the problem, commonly understood and used in the art for many years, has consisted in running both the fresh air inlet pipe, through which oxygen is supplied to the burner, and the exhaust flue pipe, through which the combustion gases are discharged, to the outside of the building to be heated, with the open ends of both pipes near one another. The theory underlying such arrangement is that any wind blowing into the flue would also blow into the air inlet, and that the opposing air pressures resulting would offset each other, thus leaving the natural gravity draft free to operate the system. It was shown that in the year 1872, a British inventor named Southby improved the above described arrangement by surrounding the open ends of the air inlet pipe and the exhaust flue pipe with a vertical housing, open at the top and bottom; the fresh air and flue gases were kept separated from each other during the operation of the gas burner by a natural gravity draft.

The physical exhibits, as well as the record testimony, reveal that both the Martin patent in suit and appellant's "Saf-Aire" gas heater bear some resemblance in principle and method of operation to their common ancestor, the British Southby patent. Martin adopted the cylindrical housing of the Southby patent, but covered over and partially closed off with end baffles both the upper and lower openings of the housing, the whole system being symmetrical. The effect of the end baffles was to impede the natural draft through the housing, which made it necessary for Martin to add some physical means to keep the combustion gases separated from the fresh air. In order to accomplish this purpose, Martin extended his inlet and outlet pipes into the cylindrical housing and turned them away from one another to form L-shaped terminals or elbows.¹

The accused device, or "Saf-Aire" heater, is a gas-burning room heater designed to be built into an outside wall of a building. It also has a vertical housing similar to the old Southby apparatus, but instead of obstructing the natural upward draft through the housing by means of end baffles as Martin did in his patent, the evidence tends to show that appellant's "Saf-Aire" heater was designed so as to make the air inlet opening in the form of a wide-open funnel or scoop which concentrates at the air inlet the force of the wind striking the housing, regardless of the direction from which it blows. Further, the "Saf-Aire" heater, like the old Southby device, makes use of a continuous natural draft upward through its housing, thereby separating the combustion gases from the fresh air by means of gravity and air pressure, and no physical separating means, as such, is used.

Appellees contend, however, and the district court found, that appellant's "Saf-Aire" heater infringes claims 1 and 2 of their Martin patent, which claims read as follows:

"1. The combination with a fuel burner having an air inlet conduit and a flue, of a draft equalizer comprising a housing, exhaust openings and intake openings in said housing, baffle means adjacent said openings, the outer ends of said air conduit and flue projecting through the wall of said housing and terminating within the latter, and separate means for preventing the admixture of flue gases with the fresh air drawn into said conduit.

"2. In combination with a fuel burner, a closed burner box, an air inlet conduit leading into said box, a flue leading from said box, a draft equalizer, including a housing, intake and exhaust openings in said housing, baffles adjacent said openings, said conduit and flue leading into said equalizer, and means within said equalizer for preventing the admixture of flue gases with the fresh air drawn into said conduit."

Appellants contend (1) that the "Saf-Aire" heater differs radically in structure and method of operation from the Martin patent and resembles it only to the extent that both structures resemble the old Southby patent;² (2) that the Martin patent is invalid in view of the prior art; and (3) that the Martin patent has been used by appellees in violation of the anti-trust laws and has thereby become unenforceable.

Ordinarily the better practice would be to pass upon the validity of the Martin patent. Sinclair & Carroll Co. v. Interchemical Corp., 325 U.S. 327, 330, 65 S.Ct. 1143, 89 L.Ed. 1644. That patent, however, has no pioneer status, but at most is an improvement...