Grace Instrument Industries, LLC v. Chandler Instruments Co.,, No. 21-2370 (Fed. Cir. 2023)Annotate this Case
Grace sued Chandler alleging infringement of its 877 patent, which concerns measuring the viscosity of the fluid in oil wells. The patent’s design is intended to eliminate measurement error because of sample mixing with pressurization fluid in a comparative viscometer. The district court construed the term “enlarged chamber” as indefinite and the term “means for driving said rotor to rotate located in at least one bottom section.” The parties then stipulated that 11 asserted claims were invalid and that certain claims were not infringed.
The Federal Circuit vacated the district court’s determination that the term “enlarged chamber” is indefinite and remanded. Although “enlarged chamber” is not a term of art, the intrinsic record sufficiently guides a skilled artisan to the meaning of that term as used in the patent as “a chamber that is large enough to contain excess test sample prior to pressurization to prevent mixing of the test sample and pressurization fluid in the lower measurement zone when the test sample is pressurized to maximum rated pressure.” The court affirmed the construction of “means for driving said rotor to rotate located in at least one bottom section.”