FMC Corporation v. City of Greensboro

• Decision Date: 03 September 1962
• Docket Number: Civ. A. No. C-57-G-60.
• Court: U.S. District Court — Middle District of North Carolina
• Parties: FMC CORPORATION, Plaintiff, v. The CITY OF GREENSBORO, Defendant.

208 F. Supp. 494

FMC CORPORATION, Plaintiff, v. The CITY OF GREENSBORO, Defendant.

Civ. A. No. C-57-G-60.

United States District Court M. D. North Carolina, at Greensboro.

August 28, 1962.

As Amended September 3, 1962.

Schneider, Dressler, Goldsmith & Clement, Chicago, Ill.; McLendon, Brim, Holderness & Brooks, Greensboro, N. C., of counsel; R. Howard Goldsmith, Chicago, Ill., Thornton H. Brooks, Greensboro, N. C., Charles W. Ryan, Chicago, Ill., for plaintiff FMC Corporation.

Victor Myer, Olson, Mecklenburger, von Holst, Pendleton & Neuman; Louis Robertson, Darbo, Robertson & Vandenburgh, Arlington Heights, Ill.; Welch Jordan, Jordan, Wright, Henson & Nichols, Greensboro, N. C.; Jack Elam, City Atty. of Greensboro, N. C., of counsel, for defendant.

HAYES, District Judge.

The Forrest Patent No. 2,777,815, granted January 15, 1957, on an application filed June 8, 1953, embodies a sewage digestion process. It teaches the method of continuously injecting methane-containing digester gas under pressure near the bottom of the tank and at the center by releasing gas under prescribed conditions of force propelling it to the top of the surface and rolling it from the center to the circumference, down the sides of the container, back to the bottom and up again in the same circular, continuous movement. This method contemplated the inter-mixture of the gas with the sludge and keeping it in continuous motion, which would prevent scum from forming and the solids from settling at the bottom until the sludge was fully digested. The method also contemplated the continuous movement of the gas when raw sludge was introduced into the container or while withdrawing digested sludge. The patent teaches that by this process the sludge becomes thoroughly digested in a 10-day period, whereas under the conventional method prior to that it required 30 days for the operation. This process also resulted in reducing storage capacity to one-third of what was required under the conventional method.

The City of Greensboro, in 1938, in establishing the sewage plant, erected two tanks, each 75 feet in diameter and 17½ feet deep, which were adequate to take care of the sewage flow at that time by the conventional method. But by 1958 the City's sewage and commercial waste had increased about three times, making it necessary to increase the sludge facilities or make some other provisions. The City employed capable engineers of New York, Hazen and Sawyer, to prepare necessary plans to meet these difficulties, and they had prepared plans for the construction of two additional tanks, each of which was 90 feet in diameter, at a cost of $270,000.00 to meet the current and anticipated needs of the City of Greensboro.

When these engineers were made aware of the new process of Forrest, they discovered that by using the Forrest process they could get along with their present sludge equipment and avoid the construction of the two anticipated tanks and thereby save the City a net sum of $210,000.00.

Competitive bids were submitted by the Chicago Pump Co., Assignee of the Forrest Patent, Pacific Flush Tank Co. and by Walker Process Equipment, Inc. The contract was awarded to Walker Process Equipment, Inc., which agreed to accomplish the result contemplated by the Forrest Patent without the payment of any royalty for its use and under a guarantee by Walker Process Equipment, Inc., to hold the City of Greensboro harmless against any expense, costs or damages that it might incur for infringing the Forrest Patent. In this way the City of Greensboro was able to use the benefit of the Forrest Patent without paying any royalty therefor. When Food Machinery and Chemical Corporation, the parent corporation of Chicago Pump Company, filed a suit against the City of Greensboro for damages, Walker Process Equipment, Inc., took charge of the defense in behalf of the City and conducted its defense throughout the trial.

The taking of testimony in the case consumed five full weeks, and one full day was devoted to oral arguments. The defendant, City of Greensboro, by Walker Process Equipment, Inc., has denied infringement, denied the validity of the Forrest Patent and pleaded unclean hands against equitable relief. The principal witness for the plaintiffs was the patentee, Mr. Forrest, who was an exceptionally capable engineer and impressed the Court as being scrupulously honest in his testimony. The Court, therefore, feels it can rely on and accept his testimony as being true. It has been substantiated by documentary evidence in numerous instances.

Mr. Forrest and Messrs. Lamb and Klein were regular engineering employees of the Chicago Pump Company, and Dr. Morgan was employed as a consultant. During a long period of time experiments were conducted by him in a laboratory and by Lamb, Klein and Forrest for the purpose of devising improvements in the treatment of sewage by means of which the digestion of it could be perfected in much less time than required in the conventional method, and as a result of these experiments and tests the patent attorneys for the Chicago Pump Co. prepared and filed with the Patent Office applications by Lamb and Klein covering certain phases of their investigation, and by Forrest on the subject matter of the patent in suit, both applications being filed on the same date, to-wit, June 8, 1953. The Patent Office rejected the application of Lamb and Klein II on the teachings of German Patents Nos. 1 and 2, but allowed the Forrest Patent in suit over the German Patents, and Lamb and Klein II and over references No. 1,820,976, Imhoff, September 1, 1931; No. 2,190,598, Fisher, February 13, 1940; No. 2,528,449, Genter, et al. November 7, 1950; No. 2,638,444 Kappe, May 12, 1953; and No. 2,640,027, McNamee, et al, May 26, 1953.

Claims 1, 2, 4 and 8 of the patent in suit are at issue in this case, and those claims are set forth in the footnote as follows.¹

The Forrest Patent embodies many well-known features in the art which are utilized in the patent in connection with new features that he invented with the result that the combination effects a satisfactory digestion of the sludge in one digester tank by an accelerated digestion in a period of 10 days as against the 30 days formerly required by the conventional process. In the conventional method of digesting the sludge in one tank without the Forrest process, it required a period of 30 days, and in that method the solids settled at the bottom of the tank over which a layer of supernatant liquor was formed and over this was a layer of scum to cap it over. Forrest refers to attempts theretofore made to effect the acceleration of digestion of sewage sludge by agitating the contents of the tank using compressed gases, including gases generated during the digestion process, sometimes called "digester gas" and mechanical agitators were utilized to produce motion in the material undergoing digestion, as disclosed in German Patent 441,851, dated January 20, 1925, referred to as German Patent No. 1, and German Patent No. 2, being 492,809, dated March 20, 1930.

The prior art taught some agitation or stirring of the digesting sludge in some sections or portions of the tank either by mechanical mixers or stirrers or Fisher's razzle dazzle (propellers mounted on a shaft which stirred locally where the propellers moved) or Kappe and McNamee with gas in the scum area. Lamb and Klein I had some stirring with small amount of gas, but insufficient to perform the thorough movement of the entire contents of the tank as taught by Forrest. Experience had demonstrated that grease balls would form and solids would settle in those sections of the tank where movement ceased. Propellers clogged with accumulated particles thus hampering their functions. For this reason mechanical mixers never succeeded. It is obvious that gas directed solely to the scum problem had no appreciable effect on the entire contents of the tank.

There is some argument whether Forrest's process accelerates digestion by the contact between the sludge with the recirculated gas within the digester or whether it results from the complete rotary circulation of the entire contents of the tank. He teaches that the continuous recirculation of the digester gas in the prescribed amount to create a rotary circulation of the entire contents of a velocity of ½ to 1½ feet per second will accelerate the digestion and complete it in 8 to 10 days. If it produces that result by pursuing the steps he teaches whether the gas contact or movement, or both combined do it, the novelty is there, and resides in how to do it.

But Forrest asserts that the prior art workers did not appreciate that contacting the sludge undergoing digestion with digester gas under controlled conditions, whereby both the velocity of movement of the circulating sewage undergoing digestion, and the rate at which the digester gas is recirculated in the sludge are held within certain well defined limits, is important to the operation of anaerobic digestion process on a commercial basis. Forrest then describes his discovery that sewage sludge can be digested under anaerobic conditions in a relatively small digestion tank in a commercially feasible operation, by effecting the digestion with the aid of digester gas introduced into the materials undergoing digestion at the rate of about 1/8 to 2 cubic feet per minute per foot of longest horizontal internal cross sectional dimension of the tank and under conditions such that there is established and maintained in the material undergoing digestion a generally circular motion of a velocity of about ½ to 1½ feet per second. The gas is discharged uniformly into material undergoing digestion, preferably in a diffused state and over an appreciable area of the tank, from the region located preferably in the center and lower third of the tank. The gas rises in an upward direction after discharge. With this controlled discharge of digester gas within...