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Numerical Ranges of a Preferred Embodiment Do Not Limit Claim Language

August 17, 2006

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Last Month at the Federal Circuit - September 2006

Judges: Bryson, Archer, Gajarsa (author)

[Appealed from: S.D. Tex., Judge Rainey]

In Conoco, Inc. v. Energy & Environmental International, L.C., Nos. 05-1363, -1461 (Fed. Cir. Aug. 17, 2006), the Federal Circuit affirmed the district court’s findings of infringement.

Conoco, Inc.’s (“Conoco”) U.S. Patent No. 5,244,937 (“the ’937 patent”) claims a process for making suspension-based drag reducing agents (“DRAs”), which are high molecular weight polymers suspended within a carrier system, such as a gel. When injected into, for example, an oil pipeline, a DRA is capable of reducing friction caused by the pumping operation and, thus, is capable of improving overall efficiency. The ’937 patent discloses a process of coating the polymers with a stearate partitioning agent to prevent agglomeration of the polymers, as well as replacing the gel as a carrier system with water or a water-alcohol liquid medium. Conoco’s U.S. Patent No. 6,172,151 (“the ’151 patent”) improves the process by disclosing the use of a fatty acid wax as the partitioning agent, instead of a stearate, in a nonaqueous suspension.

Conoco sued Energy & Environmental International, L.C. (“EEI”), alleging that EEI had infringed the ’937 and ’151 patents. EEI stipulated to the validity and enforceability of the patents. The district court held that EEI literally infringed claim 1 of the ’937 patent. The court further held that EEI infringed claims 1-3 of the ’151 patent under the DOE and enjoined EEI from further activities that would infringe the patent. Subsequently, after a contempt hearing, the district court clarified its order and expanded the injunction, prohibiting EEI from manufacturing its reformulated product using polyethylene wax (“PE wax”).

On appeal, the Federal Circuit held that the district court correctly construed the claim term “water-alcohol mixture” to mean “more than negligible amounts of water and alcohol.” The Court noted that a disclosure of a preferred embodiment by itself is not enough to demonstrate a clear disclaimer of an ordinary meaning of a claim term. In particular, the Court concluded that the statements in the specification that the amount of alcohol in the suspending material “may vary widely” and that it “usually forms between about 0 and 70 weight percent of the suspending material” demonstrated that there was no clear intention to limit the ordinary meaning of the claim language.

Regarding the construction of the terms “consisting of” and “stable nonagglomerating suspension,” the Federal Circuit held that, although EEI did not raise the construction of these terms at the district court level, the doctrine of waiver on appeal did not apply. Specifically, the Court held that “consisting of” is a term of art in patent law with its own construction. And, although EEI did waive its rights regarding the construction of the term “stable nonagglomerating suspension,” because the district court explicitly construed the term sua sponte in its Findings of Facts and Conclusions of Law, the construction must also be reviewed.

The Federal Circuit explained that, while the term “consisting of” excludes nonrecited components and steps, it does not exclude components and steps that are unrelated to the invention or impurities that are normally found in any of the listed components. Therefore, the Court agreed with the district court’s finding that any nonalcohol and nonwater components in EEI’s product were impurities and the district court did not err in finding that the product met the limitations of the claim.

Further, relying on the intrinsic and extrinsic evidence, the Federal Circuit held that the district court properly construed the term “stable nonagglomerating suspension” to mean stable “at the time the DRA is introduced into the pipeline.” The Court explained that the district court’s construction recognized that the suspension could be assessed at the time of introduction and did not have to be transported over long distances. Moreover, the Court held that the district court did not err in its application of the facts to the construction, as there was sufficient evidence to support the finding that EEI’s product was stable when injected.

The Federal Circuit also agreed with the district court’s finding of infringement under the DOE, rejecting EEI’s argument that Conoco was estopped from claiming a fatty acid wax equivalent in view of the prosecution history of the ’151 patent. During prosecution of the application, an Examiner’s Amendment was made toadd the term “fatty acid wax” to the one claim that lacked the limitation, but the record did not contain an explicit explanation for the amendment. The Court explained, however, that the absence of an explanation for the amendment is not an absolute bar and can be rebutted. The Court went on to note that throughout the prosecution history, the Examiner and Applicants focused their arguments around this limitation as if it were present in the claims. Therefore, the Court concluded the amendment was not made for reasons related to patentability, but instead made to correct an obvious omission.

Moreover, the Court noted that a clear and unmistakable surrender of subject matter must be evident for argument-based estoppel to be applied. In the prosecution of the ’151 patent, Applicants argued that “fatty acid wax,” a stearamide derivative, was not equivalent to another stearamide derivative, “metal stearates,” as disclosed in cited prior art. The Court explained that this argument demonstrates a clear surrender of “metal stearates” as an equivalent, but does preclude Applicants from other possible fatty acid wax equivalents.

The Court also affirmed the district court’s extension of the injunction to encompass PE wax, stating that the district court heard sufficient evidence to conclude that PE wax and “fatty acid wax” are functionality equivalent and, therefore, the extension of the injunction was proper.