103 F.3d 1538 (Fed. Cir. 1997), 95-1504, Micro Chemical, Inc. v. Great Plains Chemical Co., Inc.

Docket Nº:95-1504, 95-1514.
Citation:103 F.3d 1538
Party Name:41 U.S.P.Q.2d 1238 MICRO CHEMICAL, INC, Plaintiff-Appellant, v. GREAT PLAINS CHEMICAL CO., INC., Lextron, Inc., and Robert C. Hummel, Defendants-Cross/Appellants, and William Pratt, Defendant.
Case Date:January 03, 1997
Court:United States Courts of Appeals, Court of Appeals for the Federal Circuit

Page 1538

103 F.3d 1538 (Fed. Cir. 1997)

41 U.S.P.Q.2d 1238

MICRO CHEMICAL, INC, Plaintiff-Appellant,


GREAT PLAINS CHEMICAL CO., INC., Lextron, Inc., and Robert

C. Hummel, Defendants-Cross/Appellants,


William Pratt, Defendant.

Nos. 95-1504, 95-1514.

United States Court of Appeals, Federal Circuit

January 3, 1997

Rehearing Denied March 3, 1997.

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Timothy B. Dyk, Jones, Day, Reavis & Pogue, Washington, D.C., argued, for plaintiff-appellant. With him on the brief were John P. Pinkerton, Ross Spencer Garsson, and Carl F. Schwenker, Dallas, TX, and Gregory A. Castanias, Washington, D.C. Of counsel on the brief was John Mozola, Sprouse, Mozola, Smith & Rowley, P.C., Amarillo, TX.

Dennis J. Mondolino, Hopgood, Calimafde, Kalil & Judlowe, New York City, argued for defendants-cross/appellants. With him on the brief were Michael F. Hurley and Edward M. Reisner.

Before ARCHER, Chief Judge, MAYER and LOURIE, Circuit Judges.

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LOURIE, Circuit Judge.

Micro Chemical Inc. appeals from the judgment of the United States District Court for the District of Colorado that U.S. Patent 4,733,971 is invalid and was not infringed by the defendants. Micro Chem. Inc. v. Great Plains Chem. Co., 900 F.Supp. 1386 (D.Colo.1995). Great Plains Chemical Co., Inc., Lextron, Inc., and Robert C. Hummel (collectively "Lextron") appeal from the district court's judgment that the patent was not obtained by means of inequitable conduct. Id. Because the district court erred in concluding that the patent is invalid, but did not err in concluding that certain of the asserted claims were not infringed and that the patent was not obtained by means of inequitable conduct, we affirm-in-part and reverse-in-part. We remand for a determination of infringement of certain asserted claims not addressed by the district court.


The '971 patent concerns a method and apparatus for adding small amounts of ingredients ("microingredients") to livestock or poultry feed in order to promote growth and to prevent sickness. Figure 4 of the patent is a front view of the internal parts of the machine (10). The microingredients are stored in bins (68, 74), below which is a weighing hopper (122) supported by a "weigh frame" (34). A mixing vessel (170) is located beneath the weighing hopper and is supported by a separate main frame (46). The machine is controlled by a "weigh microcomputer" and a machine sequencing microcomputer. The patent discloses a block diagram for the computer components and flow charts illustrating software for controlling the operation of the computers and the machine. An operator programs the desired types and amounts of microingredients into the machine, and the computers control the machine in order to weigh microingredients in the weighing hopper, dispense them into the mixing tank, and mix them with a liquid carrier such as water in order to form a slurry to be sprayed onto the feed.

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The machine includes elements for isolating the sensitive equipment of the weighing mechanism from the adverse effects of vibrations or other disturbances that might affect its accuracy. These include isolation pads (44) that dampen vibrations transmitted to the "weigh frame" from the floor on which it is placed. The separate "weigh frame" (34) isolates the weighing equipment from the mixing equipment and other components, which are supported by their own frame (46). The mixing equipment generates substantial vibrations caused by agitation during the mixing process, and use of a separate frame reduces the transfer of those vibrations to the weighing system. An antisway bar (276) dampens transverse motion. The machine is enclosed by panels (12), which shield its components from dust and other contaminants and also protect the weighing system from external forces such as wind or other jarring contact that may affect its accuracy. The panels (12) are shown in Figure 1 of the patent. According to the specification of the patent, the isolation of the weighing equipment results in consistently accurate weighing of microingredients.

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Claim 1, which recites the isolation feature, reads as follows:

1. An apparatus for measuring, dispensing, and delivering microingredient feed additive concentrates in small but accurate amounts in a liquid carrier slurry into a livestock or poultry feed ration shortly before the delivery of said feed ration to the animals for consumption, said apparatus comprising:

multiple storage means for storing separately a plurality of different microingredient feed additive concentrates;

multiple dispensing means for dispensing separately several additive concentrates from said multiple storage means;

weighing means for determining the weights of said different additive concentrates dispensed;

isolating means for isolating said weighing means from influences affecting the weighing function of said weighing means so accurate weight determinations are obtained;

control means for controlling separately the operation of said plural dispensing means in response to weight determinations of said weighing means to control the weight of additive concentrates dispensed;

receiving means for receiving additive concentrates dispensed from said storage means;

mixing means for mixing a liquid carrier with the additive concentrates dispensed into said receiving means to form a slurry of said carrier and the dispensed additive concentrates; and

delivery means for delivering said slurry to a slurry-receiving station for mixing with a feed ration.

The patent also discloses and claims a method of delivering microingredients using sequential and cumulative weighing. During sequential weighing, the weighing hopper is inverted in order to dump each weighed microingredient into the mixing tank and it is then reverted to receive and weigh the next microingredient. During cumulative weighing, microingredients are repeatedly dumped on top of one another in the weighing hopper as a computer resets a scale to zero after each microingredient is added to the weighing hopper. Claim 47, which includes the sequential and cumulative weighing feature, reads as follows:

47. A method of dispensing and delivering microingredient feed additives into a livestock feed ration shortly before delivering

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the feed ration to the livestock for consumption, comprising the steps:

storing separately multiple said additives in concentrate form;

dispensing predetermined weights of selected said additive concentrates into a liquid carrier with no substantial intermixing of the additive concentrates before they enter the liquid carrier;

intermixing the additive concentrates in the liquid carrier to dilute, disperse, and suspend them and form a liquid carrier-additive slurry;

directing the slurry to a receiving station while maintaining the suspension and dispersion of the additives until delivered into a feed ration; and

determining the predetermined weights of selected additives by weighing each additive sequentially and cumulatively in a common weighing container while maintaining separation of the different concentrates in said container.

The development of the '971 invention began in 1984 when the inventor, William C. Pratt, conceived the idea of a weighing and delivery system having improved accuracy compared to prior art systems. In December 1984, before the critical date of February 26, 1985, 1 Pratt offered to sell a weighing machine to Lee Isaac, manager of the Sunbelt feedlot located in Hugoton, Kansas. Isaac rejected his offer and instead purchased a machine sold by Lextron. Although Pratt had built and tested a weighing system for the machine allegedly offered at that time, he had not constructed a slurry or mixing system for use with the weighing system. He did have a "rough" sketch of the mixing system.

In January 1985 Pratt constructed a prototype that included both the weighing and the mixing systems. He encountered several problems during testing of this prototype. His primary challenge was in isolating the weighing system from the adverse effects of vibrations caused by the mixing system and by other sources. Because of its sensitivity, the weighing system was liable to provide incorrect measurements as a result of these vibrations. Pratt constructed another prototype in February 1985, but it also did not accurately weigh microingredients consistently. In late February he incorporated additional elements into that prototype in order to achieve adequate isolation of the weighing system. The improved February prototype contained as isolating elements a separate "weigh frame," rubber isolation pads, and longitudinal and lateral stabilizers. He also added a three-speed mixer to the mixing tank to intermix the microingredients with a liquid carrier and he used two RCA computers for controlling operation of the machine. It produced satisfactory results when tested and it was presented to a group of Tulsa bankers on February 28, 1985, after the critical date.

Three days after the patent issued, Micro sued Lextron, Great Plains Chemical Co., Inc., and Robert C. Hummel 2 for infringement. 3 Micro alleged that Lextron infringed the patent by manufacturing and selling microingredient additive machines referred to as "cumulative weigh" and "weigh/dump" machines. Micro also alleged that Lextron induced infringement by providing what it referred to as "no-mix" machines to feedlots owned by Cactus Feeders. Lextron counterclaimed for a declaratory judgment of invalidity and noninfringement. 4 In March 1993, the district court...

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