Micro Chemical v. Great Plains Chemical

• Decision Date: 06 October 1999
• Parties: (Fed. Cir. 1999) MICRO CHEMICAL, INC., Plaintiff/Counterclaim Defendant-Appellant, and WILLIAM PRATT, Counterclaim Defendant, v. GREAT PLAINS CHEMICAL CO., INC., LEXTRON, INC. and ROBERT C. HUMMEL, Defendants/Counterclaimants- Appellees. 98-1393 DECIDED:
• Court: U.S. Court of Appeals — Federal Circuit

Page 1250

194 F.3d 1250 (Fed. Cir. 1999)

MICRO CHEMICAL, INC., Plaintiff/Counterclaim Defendant-Appellant, and WILLIAM PRATT, Counterclaim Defendant, v. GREAT PLAINS CHEMICAL CO., INC., LEXTRON, INC. and ROBERT C. HUMMEL, Defendants/Counterclaimants- Appellees.

98-1393

United States Court of Appeals for the Federal Circuit

DECIDED: October 6, 1999

Appealed from: United States District Court for the District of Colorado Senior Judge Zita L. Weinshienk

[Copyrighted Material Omitted]

[Copyrighted Material Omitted] Gregory A. Castanias, Jones, Day, Reavis & Pogue, of Washington, DC, argued for plaintiff/counterclaim defendant-appellant, Micro Chemical, Inc. and counterclaim defendant, William Pratt. With him on the brief was Thomas M. Fisher. Of counsel on the brief was John Mozola, Mullin, Hoard & Brown, L.L.P., of Amarillo, Texas. Of counsel was Richard P. Holme, Davis, Graham, of Denver, Colorado.

Dennis J. Mondolino, Hopgood, Calimafde, Kalil & Judlowe, LLP, of New York, New York, argued for defendants/counterclaimants-appellees. With him on the brief was Michael F. Hurley.

Before PLAGER, RADER, and BRYSON, Circuit Judges.

RADER, Circuit Judge.

Following a bench trial, the United States District Court for the District of Colorado determined that Great Plains Chemical Company, Inc., now Lextron, Inc. (Lextron), did not infringe Micro Chemical, Inc.'s U.S. Patent No. 4,733,971 (the '971 patent). The '971 patent relates to devices and methods for dispensing the proper amount of additives into livestock feed rations. Because, under a correct claim construction, the district court's finding that the accused device does not infringe claims 63, 74, 93, and 94 is clearly erroneous, this court reverses the district court's judgment of non-infringement. However, because the district court's finding of non-infringement of claim 91 is not clearly erroneous, this court affirms that judgment of non-infringement. This court also affirms the district court's summary judgment that released Mr. Robert C. Hummel, Lextron's president, from personal liability for infringement.

I.

The '971 patent discloses machines and methods for weighing, dispensing, and delivering microingredients into livestock feed. Microingredients include any type of feed additive such as vitamins and medicine. The machines and methods measure the microingredients, either by weight or by volume, and then add them to a liquid. The machines and methods then mix the microingredients with the liquid to form a slurry before applying them to the feed.

In the '971 patent's preferred embodiment, suspension frames suspend the ends of a compartmented subframe. Col. 6, ll. 10-16. A weigh tower is located at each end of the weigh hopper. A load cell in each weigh tower measures the cumulative weight of the hopper and its contents. Col. 10, ll. 17-24. These load cells send the weight measurements to a central processing unit (CPU). Col. 10, ll. 20-22. In operation, a first microingredient storage bin dispenses a microingredient into one of the hopper's compartments until the CPU registers the proper weight. Col. 11, l. 1 to col. 14, l. 17. Then each storage bin, in turn, pours its microingredient into a separate hopper compartment. The CPU uses the cumulative weight measurement from the load cells to regulate the amount of each microingredient added. The process continues until each separate chamber of the hopper contains the correct amount of a different microingredient. This process - use of a compartmented hopper to weigh multiple microingredients before dispensing them into the liquid - is known as the "cumulative weigh" method.

When the hopper has the proper contents, the preferred method inverts the hopper and vibrates it to discharge the microingredients into a mixing vessel containing a liquid. Col. 8, l. 37 to col. 9, l. 12. Variable speed mixers then mix the microingredients with the liquid to form a liquid slurry. Col. 9, ll. 13-32. Finally, a plumbing system delivers the slurry from the mixing vessel to the feed. Col. 9, l. 61 to col. 10, l. 2.

The '971 patent specification describes alternative embodiments of the invention. One alternative embodiment dispenses each microingredient into the liquid carrier directly from the storage bins. Col. 19, l. 60 to col. 20, l. 15. In this embodiment, a load cell supporting each storage bin measures the bin weight. By measuring the decreasing bin weight, the CPU again ensures that a proper amount of each ingredient enters the slurry. This method, known as the "loss of weight" method, eliminates the need for a hopper altogether. Col. 19, ll. 60-61. A variation of this embodiment measures the amount of microingredient dispensed from the storage bin using a weight per unit time formula, or volumetric metering mode, rather than a load cell. Col. 20, ll. 16-20. Yet another embodiment uses volumetric measurement of liquid microingredients in combination with weight measurement of solid microingredients. Col. 20, ll. 54-60.

Lextron manufactures and sells microingredient feed additive systems. Initially, Lextron made and sold "type one" machines which used a cumulative weigh method similar to the '971 patent's preferred embodiment. After issuance of the '971 patent, however, Lextron stopped producing and selling the type one machines. Instead, it adapted its machines to a "type two" configuration. The type two machines used a method of weighing and dumping each additive one at a time into the liquid. This method, known as the "weigh dump" method was featured in a prior art system, the Brewster system. In this respect, Lextron's type two machine was similar to the Brewster system. The type two machines are the only machines at issue on this appeal. The parties have settled their dispute with respect to the type one machines.

The '971 patent issued on March 29, 1988. Two days later, Micro Chemical sued Lextron for direct infringement and its President, Robert C. Hummel, for inducement to infringe. In a 1995 decision, the district court held the claims of the '971 patent invalid under 35 U.S.C. §§ 102(b) and 103 (1994). See Micro Chem., Inc. v. Great Plains Chem. Co., 900 F. Supp. 1386 (D. Colo. 1995). The district court also found the patent's "isolation" claims not infringed. See id. On appeal from that decision, this court reversed the findings of invalidity but upheld the finding of non-infringement of the isolation claims. See Micro Chem., Inc. v. Great Plains Chem. Co., 103 F.3d 1538, 1540, 41 USPQ 2d 1238, 1240 (Fed. Cir. 1997). This court then remanded the case to the district court for a determination of infringement with respect to the remaining asserted claims. See id.

Five claims remain at issue, apparatus claims 74 and 91 and method claims 63, 93, and 94. Apparatus claim 74 recites:

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 additives separately from said multiple storage means;

weighing means for determining the weights of selected additives dispensed by said dispensing means from said storage means;

a mixing vessel for receiving a liquid carrier and the dispensed and weighed additive concentrates;

flow-inducing means for inducing a flow of liquid carrier within said mixing vessel and thereby mixing said carrier with the dispensed additive concentrates to form a slurry;

delivery means for delivering said slurry from said mixing vessel to a remote slurry-receiving station for mixing with the feed ration; and

control means operable to:

(a) control 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;

(b) operate said flow-inducing means to cause a positive intermixing of the dispensed additive concentrates and the liquid carrier within said mixing vessel before discharge of liquid carrier from said vessel;

(c) operate said delivery means to deliver slurry to said receiving station after the slurry is formed in said mixing vessel by said flow-inducing means.

(emphasis added). The only disputed limitation of this claim is the "weighing means" element. Apparatus claim 91 contains a similar disputed element: "weighing means on said support frame means for weighing predetermined weights of said different additive concentrates dispensed into said multiple hopper container means by said dispensing means." (emphasis added).

The district court identified these two disputed claim elements as means-plus-function elements under 35 U.S.C. § 112, ¶ 6 (1994). Based on its examination of the preferred embodiment described in the specification, the district court concluded that the corresponding structure included weigh towers - containing suspension-type load cells, suspension arms, and dampening rods - and a partitioned, inverting hopper. Thus, the district court interpreted these claims to require each of these specific structural elements or their equivalents.

The district court also relied on statements in the background section of the patent when interpreting these claims. In that section, the applicant discussed the specific disadvantages of the prior art Brewster system:

It is believed that such system weighed and then dispensed each additive separately and sequentially. It is believed that such system was unsuccessful because it was too slow and too inaccurate for handling additive concentrates in a feedlot environment.

Col. 2, ll. 12-18. The district court read this language to disavow any coverage of the weigh dump method. The district court therefore limited the...