“Gradual” and “Continuous” Includes Step-Wise

By on November 19, 2020
Posted In Patents

The US Court of Appeals for the Federal Circuit affirmed a priority decision in favor of the senior party, upholding a claim construction that was based upon a verbatim definition set forth in the patent specification of the application from which the count in interference was copied. Chevron U.S.A. Inc. v. University of Wyoming Research Corp., Case No. 19-1530 (Fed. Cir. Nov. 4, 2020) (Schall, J.) (Newman, J., dissenting).

Wyoming Research provoked a patent interference proceeding by copying into its pending application a claim from Chevron’s pending patent application. Under the now-discontinued interference statute, the patent for an invention claimed by more than one party was awarded to the first-to-invent party. If the Patent Trial and Appeal Board (Board)determined there was an interference in fact—that is, two patent applications claimed the same subject matter—then the Board could proceed to determine priority of inventorship. A finding of interference in fact required the copying party’s patent specification to contain adequate written description and enablement to support the copied claim.

The copied claim was directed to a method of fractioning asphaltenes from crude oil. The technology used a mobile phase into which an alkane solvent was introduced and its concentration “gradually and continuously” changed over time, and the resulting eluted fractions were analyzed. The disputed claim limitation was: “gradually and continuously changing the alkane mobile phase solvent to a final mobile phase solvent.”

Chevron argued that “gradually and continuously changing” referred to the act of feeding alkane mobile phase solvent into the inlet of the column. Relying on intrinsic evidence, the Board instead adopted Wyoming’s construction, concluding that the limitation’s “gradually and continuously changing” referred to the change of solvents in the column and not to changes at the inlet to the column. The distinction was important because at the inlet, the Wyoming invention introduced solvent in a step-wise manner. The parties agreed that Wyoming’s specification supported only the construction adopted by Board, and Wyoming was declared to be the senior party for the priority contest.

Because Chevron had filed a priority statement that indicated that its earliest corroborated conception coupled with diligence date was later than Wyoming’s priority date, the Board determined that Chevron was unable to prevail on priority and entered judgment in favor of Wyoming. Chevron appealed.

On appeal, Chevron argued that the Board’s construction was inconsistent with Chevron’s patent specification. Chevron contended that its application disclosed that the solvent was “gradually and continuously” changed at the column’s inlet and that the Board’s construction rendered the limitation meaningless because it encompassed even “sudden, abrupt immediate solvent switches.”

The Court affirmed the Board’s construction, holding that the broadest reasonable construction of “gradually and continuously changing” did not require a change of solvents at the column inlet. The Court reasoned that the Board’s construction was consistent, and indeed tracked verbatim, with the Chevron application’s express definition of “gradually.” While the Court acknowledged that certain examples in the Chevron application illustrated that one way to implement a “gradual and continuous change” of the solvent was to “gradually and continuously” add solvents to the column, those examples did not limit the “changing” to occurring at the column inlet.

Judge Newman argued in dissent that there was no interference in fact between the Wyoming and Chevron patent applications. Rather, in Judge Newman’s view, “Chevron and Wyoming describe[d] and claim[ed] different inventions.” The Wyoming technique contemplated step-wise changes in the concentration of the solvent (which she characterized as “abrupt” and “discontinuous”), while the Chevron invention contemplated that the solvent concentration changed in a smooth fashion over time without step-wise changes (which she characterized as “gradual” and “continuous”) through a drop-wise, titrating change in concentration. In Judge Newman’s view, “[a]n abrupt solvent input change is not a gradual and continuous change, on any theory of interference priority.”

Because the Wyoming application contained no evidence of any inventor’s conception, written description or enablement of Chevron’s “gradual and continuous” method, Judge Newman argued that Wyoming’s application could not establish the required conception and constructive reduction to practice of the Chevron method.

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