Otto v. Koppers Company

• Decision Date: 10 July 1957
• Docket Number: No. 7401.,7401.
• Citation: 246 F.2d 789
• Parties: Carl OTTO, Appellant, v. KOPPERS COMPANY, Inc., a Delaware Corporation, and Wheeling Steel Corporation, a Delaware Corporation, Appellees.
• Court: U.S. Court of Appeals — Fourth Circuit

246 F.2d 789 (1957)

Carl OTTO, Appellant, v. KOPPERS COMPANY, Inc., a Delaware Corporation, and Wheeling Steel Corporation, a Delaware Corporation, Appellees.

No. 7401.

United States Court of Appeals Fourth Circuit.

Argued April 12, 1957.

Decided July 10, 1957.

W. Brown Morton, Jr., New York City (Robert McKay, Pennie, Edmonds, Morton, Barrows & Taylor, John E. Hubbell, Myron Cohen, Hubbell & Cohen, of New York City, Frank A. O'Brien, Jr., and O'Brien & O'Brien, Wheeling, W. Va., on brief), for appellant.

Jo. Baily Brown, Pittsburgh, Pa. (Brown, Critchlow, Flick & Peckham, Pittsburgh, Pa., Schmidt, Hugus & Laas, and Wright Hugus, Wheeling, W. Va., John M. Crimmins and Karl B. Lutz, Pittsburgh, Pa., on brief), for appellees.

Before PARKER, Chief Judge, and SOBELOFF and HAYNSWORTH, Circuit Judges.

HAYNSWORTH, Circuit Judge.

This is a suit for infringement of Patent No. 2,599,067,¹ for the production of ammonium sulphate, which was issued to the plaintiff, Otto, on June 3, 1952, upon an application filed March 15, 1948. From a judgment holding the patent invalid for anticipation, the plaintiff has appealed to this Court.

The claims of the patent relate to a method of producing ammonium sulphate in crystalline form by reacting ammonia in coke oven gas with an acidified saturated ammonium sulphate solution entraining crystals of ammonium sulphate. The basic method claims 1, 2, 4, 7 and 8 and the basic apparatus claims 14, 15, 16, 18 and 19, which are claimed to be infringed, are set forth in the margin.

Since the underlying principle was not new with Otto, the problem will be clarified by reference to the art as practiced in commercial installations in coke oven by-product plants prior to the time of the claimed invention in 1946.

Coke oven gas normally contains ammonia. If subsequent use of the gas is to be made, the ammonia is a deleterious substance and it is essential that substantially all of it be removed. The record indicates that a residue of as much as 3% of the ammonia content of the gas will be unacceptable in commercial practice. A residue of less than 1% is desirable.

It was well-known that ammonia readily reacts with sulphuric acid to produce ammonium sulphate. Passing coke oven gas through solutions containing sulphuric acid has long been known in practice as a means of extracting substantially all of the ammonia from coke oven gas and producing a useful byproduct, crystalline ammonium sulphate. The commercial practice of the art, however, developed along two more or less independent and parallel lines.

In 1940, most of the commercial installations in this country for the accomplishment of this purpose were saturators with one or more cracker pipes, the open ends of which were immersed to a depth of several inches in a bath of supersaturated ammonium sulphate solution containing sulphuric acid. The gas was pumped downwardly through the cracker pipe and the liquid seal of the bath from whence it bubbled up through the bath and passed on to an exhaust pipe above the bath.

This method was fully effective in cleansing the coke oven gas of the ammonia to an acceptable degree. Since the bath was a supersaturated solution of ammonium sulphate, crystals of ammonium sulphate were formed in the bath, the heavy ones falling to the bottom of the bath from whence they could be removed for subsequent processing and sale for use as agricultural fertilizer. Sulphuric acid was constantly added to replace that consumed in the formation of ammonium sulphate.

This apparatus tended to form fine salt which would cake in solid form on the apparatus itself so that it was necessary from time to time to "kill" the bath with water and acid in order to remove salt deposits from the apparatus. At such times the production of crystals, of course, was interrupted, though the cleansing of ammonia from the gas was not.

The cracker pipe installations required that gas be pumped against the head of the liquid seal of the mother liquor so that the pressure differential on either side of the saturator was as much as thirty-five inches of water. This operation was costly.

Numbers of people began to work on methods of reducing the pressure differential and the gas handling capacity of such saturators.

Upon an application filed in 1943, Patent No. 2,423,794 was issued in 1947 to the plaintiff in this action for a saturator having a flared mouth on the cracker pipe. The flared mouth caused the gas to pass more or less horizontally through the bath before bubbling upward to the surface. It permitted the apparatus to be operated with the cracker pipe immersed less deeply in the bath while successfully handling a given volume of gas. During the 1940's a number of installations of saturators of this design were made in this country including one by the defendant, Koppers, for the defendant, Wheeling Steel Corporation, at its plant at Follansbee, West Virginia.

Another method of removing ammonia from coke oven gas and converting it into ammonium sulphate was also known in commercial practice. For convenience this will be referred to as the "unsaturated system." Unlike the cracker pipe saturator, it employed an unsaturated solution of acidified ammonium sulphate.

Passing gas upwardly through a tower through which an appropriate fluid was simultaneously being passed downwardly in the form of a spray or droplets had long been practiced as a means of removing dust and other substances from gases by reaction or absorption. As practiced for the removal of ammonia from coke oven gas, such towers, known as "scrubbers," in modern practice were packed with tile or other material. Gas was pumped into the bottom of the tower from whence it would flow upwardly through the spaces between the packing, while at the same time a solution of sulphuric acid, or of unsaturated ammonium sulphate containing sulphuric acid, was spread over the top of the packing by perforated pipes, spray nozzles or other suitable means. As the liquid flowed over and down the sides of the packing material, it came into contact with the upwardly flowing gas. The sulphuric acid in the liquid reacted with the ammonia in the gas to produce ammonium sulphate. It had been found that such packed towers produced a more intimate contact of the gas and the liquid than an unpacked scrubber. In the packed tower the use of a spray at the top of the tower was principally for the purpose of dispersing the liquid over the top of the packing, while the reaction was effected primarily in the spaces between the packing.

In the packed tower system it was imperative that any solution of ammonium sulphate employed as the liquid be unsaturated. If at any place in the system the liquid was brought to a state of supersaturation, fine salt would quickly form to clog the system and interrupt its operation. The unsaturated ammonium sulphate solution was withdrawn from the bottom of the packed tower and passed through evaporators and crystallizers where it was brought to a state of supersaturation resulting in the formation of crystals of ammonium sulphate.

Though the cracker pipe saturator was in far wider use in this country, the Wilputte Coke Oven Corporation in 1941 turned back to the packed tower system. Since the gas did not have to be pumped against a liquid seal the pressure differential was much less than in the cracker pipe saturators, and while crystals could not be formed in the scrubbing space itself, it was claimed that production in the ancillary evaporators, crystallizers and other equipment could be so controlled as to produce larger crystals of more uniform size than in the cracker pipe saturators.

Shortly before then synthetic ammonia plants had begun to produce ammonium sulphate in larger and more uniform crystals than was ordinarily produced by the cracker pipe saturators. This was a very desirable quality and it was thought by officials at Wilputte that all coke oven by-product plants would have to meet the standards of the synthetic ammonia plants if they were to maintain their markets for ammonium sulphate crystals when the end of World War II permitted the synthetic plants to turn again to that market.

With similar concern for the quantity and quality of the ammonium sulphate crystals produced, William Tiddy, Director of Research of Semet-Solvay Engineering Corp., in 1941, had turned back to scrubbers.

From the foregoing it may be seen that as commercially practiced in this country in 1946, the production of ammonium sulphate crystals from coke oven gas, was accomplished by two different systems, one of which, the cracker pipe saturator, operated with a supersaturated solution of ammonium sulphate in the saturator itself, while the other, the packed tower scrubber, could operate only with unsaturated solutions of ammonium sulphate in the scrubber. Each system had distinct advantages and disadvantages. Except, however, for the use of sprays to supplement the work of the cracker pipe, which will be described later, no one in commercial practice had combined principles of the two systems in one installation.

In 1946 the plaintiff, Otto, developed the idea that he could obtain substantially improved results by starting with a scrubber of the type used in the unsaturated system, but stripped of all internal packing, grids or other obstruction, while spraying a solution of saturated ammonium sulphate containing entrained crystals, as used in the cracker pipe system, through spray nozzles. The spray nozzles were of a type which would result in a division of the liquid into fine droplets evenly distributed throughout the cross section of the spray. As coke oven gas was passed into the bottom of the spray tower, it passed through the sprays of saturated ammonium sulphate containing seed crystals and growth of those crystals began in the reaction area. In alternate apparatus, the sprayed liquid and the growing crystals were collected in a crystallizing pool in the...