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In an appeal from the U.S. District Court for the Southern District of Texas, the Federal Circuit vacated the district court’s determination that one of a patent’s claim terms, “enlarged chamber,” is indefinite, and remanded for further proceedings.  The Federal Circuit also affirmed the district court’s construction concerning another one of the claim terms.

Grace’s patent at issue relates to a liquid pressured viscometer used to measure drilling fluid’s viscosity in “down-hole” conditions—i.e., temperature and pressure at the drill bit while drilling.  The patent is designed to eliminate the measurement errors caused by other measurement methods.  Grace sued Chandler in the district court alleging that Chandler’s viscometer infringed multiple claims of the subject patent.  The district court issued its claim construction order, holding that the term “enlarged chamber” in claims 1 and 4 was indefinite because “enlarged” was a term of degree that necessarily called for some comparison against some baseline.  The district court rejected Grace’s argument that “enlarged chamber” could be defined by its purpose.  The district court also adopted Chandler’s proposed construction of the phrase “means for driving said rotor to rotate located in at least one bottom section.”  Pursuant to the district court’s construction, the function of the “means for driving” limitation is “driving said rotor to rotate, where the means for driving is located in at least one bottom section,” and the corresponding structure is “(i) magnetic coupling (magnetic mount, gear box or motor, driving magnet, coupling magnet), or (ii) direct drive at bottom of cell body, and known equivalents.”  As a result of the district court’s determinations, the parties stipulated that certain claims of the subject patent were invalid as indefinite, and that certain claims were not infringed.  Grace appealed.

On appeal, the Federal Circuit first addressed the district court’s holding that “enlarged chamber” is indefinite.  The Federal Circuit found that the district court erred when it declined to construe “enlarged chamber” as “the area between reduced openings that is large enough to hold excess test sample (i.e., the type of fluid normally used in these machines) to prevent mixing of pressurization fluid and test sample below the bottom fin during elevated pressurization”—as requested by Grace.  The Federal Circuit reasoned that the intrinsic record informs a skilled artisan that the patent and its claims are directed to a viscometer with an “enlarged chamber” that is large enough to prevent pressurization fluid from entering the lower section of the pressure vessel—where the viscosity of the test sample is being measured—during elevated pressurization.  In other words, the enlarged chamber has to be able to contain enough sample fluid at the pre-pressurization stage such that, during pressurization, the sample fluid level does not fall below the bottom of the enlarged chamber and into the viscometer’s lower, testing section.  This design ensures that any mixing of the pressurization fluid and compressed sample fluid occurs within the enlarged chamber and not in the lower, testing section.  Thus, in the context of the patent, the Federal Circuit found that “enlarged chamber” does not require that chamber to be larger than some baseline object, but rather that it must be large enough to accomplish a particular function.  The Federal Circuit’s construction was guided by the patent’s specifications and prosecution history, which together the Court found sufficiently guided a skilled artisan to the meaning of the term “enlarged chamber” as used in the patent.  In so holding, the Federal Circuit rejected the argument that “enlarged chamber” required an explicit definition, citing its previous holdings that a claim term may be clearly redefined without an explicit statement of redefinition, and that even when guidance is not provided in explicit definitional format, the specification may define claim terms by implication such that the meaning may be found in or ascertained by a reading of the patent documents.

As for the district court’s construction of “means for driving said rotor to rotate located in at least one bottom section,” the Federal Circuit agreed with the district court that the most natural reading required the phrase “located in at least one bottom section” to modify “means for driving” and not “rotor,” and that the intrinsic record required that the claimed “bottom section” refers to the bottom section of claim 4’s viscometer, not the pressure vessel component of the viscometer. The Federal Circuit thus affirmed the district court’s construction and judgment based thereon.

The opinion can be found here.

By Mario E. Delegato

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In re: Google LLC, Appeal No. 2022-1012 (Fed. Cir. Jan. 9, 2023)

In an appeal from an examiner’s denial of claims, the Federal Circuit reversed.  The patent concerned methods for presenting search results.  The examiner rejected the claims, relying on a combination of two pieces of prior art.  Google appealed to the Board, which agreed with the examiner’s analysis.  The Court held that the Board’s determination was not consistent with the examiner’s rationale, and was otherwise unsupported by evidence.  The PTO’s attempts to embellish those rationales on appeal were unsuccessful “because they do not reflect the reasoning or findings the Board actually invoked.”  “[S]quint as we may, we do not see the justifications invoked by the PTO on appeal reflected in the record below.”  The case was remanded for further proceedings.

The opinion can be found here.

By Nika Aldrich

In re: Stingray IP Solutions, LLC, Appeal No. 2023-102 (Fed. Cir. Jan. 9, 2023)

The Court entered a writ of mandamus, directing this case to be transferred back to the Eastern District of Texas, after Judge Gilstrap had transferred it to the Northern District of California.  At issue was whether a post-filing consent to jurisdiction in a forum would be sufficient to require transfer under Fed. R. Civ. P.  4(k)(2).  That rule allows a court to have personal jurisdiction only if the case could not have been brought in another forum.  After the complaint was filed, the defendant consented to be sued in the Northern District of California, and thus argued that Rule 4(k)(2) precluded jurisdiction in Texas.  The Federal Circuit held post-filing consent is insufficient under Rule 4(k)(2).  The Court ordered the case to be recalled to the Eastern District of Texas, where that court can make an evaluation in the first instance whether the defendant was subject to jurisdiction in Texas as of the filing of the complaint.

The opinion can be found here.

By Nika Aldrich

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This article summarizes aspects of the law and does not constitute legal advice. For legal advice for your situation, you should contact an attorney.