IP Law Daily, PATENT—Fed. Cir.: Claim construction affirmed in material integrity assessment dispute, (May 28, 2025)

By Kevin M. Finson, J.D.

A trial court’s claim construction was upheld because it was supported by the plain language of the patent specifications and claims at issue, as well as the intrinsic record.

An oil and gas company showed that there was no error in claim construction underlying a stipulated judgment of non-infringement, the U.S. Court of Appeals for the Federal Circuit has held. The trial court’s claim construction was supported by the intrinsic evidence and the plain language of the patents (Stylwan Ip Holding, LLC v. Stress Engineering Services, Inc., No. 23-1269 (Fed. Cir. May 27, 2025)).

Stylwan IP Holding, LLC and several related Stylwan entities (collectively, Stylwan) were the owners of U.S. Patents Nos. 7,231,320 (the ’320 patent); 7,403,871 (the ’871 patent); 8,050,874 (the ’874 patent); 8,086,425 (the ’425 patent); 8,428,910 (the ’910 patent); and 8,831,894 (the ’894 patent), each of which related to non-destructive systems and methods for assessing the material integrity of pipelines and pressure vessels of the sort commonly used in the oil and gas industry. Specifically, the patents claimed complex signal analysis and computational methods to determine material integrity using sensors.

Stylwan brought suit for infringement against Stress Engineering Services, Inc. (SES). After a disputed claim construction hearing the parties stipulated that under the trial court’s claim construction the accused products did not infringe. Stylwan then appealed, challenging the trial court’s claim construction. Stylwan originally challenged construction of three categories of terms, “sensor/signal,” “excitation,” and “program limitations;” however, Stylwan later conceded that affirmance on the “program limitations” alone would be sufficient to resolve the case.

Claim construction. Stylwan argued that the trial court erred by incorporating in its construction of the program limitations two specific details which it said were drawn from preferred embodiments and not from the operative language; namely, a requirement for autonomous functionality and three specific equations used to recognize the nature of material features. The court found that the patent language included the requirement that the claimed invention be autonomous throughout, and that this was apparent from the intrinsic evidence. As for the three specific equations used by the claimed inventions, the court found that those were co-extensive with the enablement. While Stylwan argued that the invention could operate with other equations instead, the asserted patents only enabled these three, and the trial court properly read them in that context as a part of the claimed invention.

The court considered the parties’ remaining arguments and found them unpersuasive. Based on the reasons stated above, the court held that the district court’s claim construction of the program limitation terms was supported by the intrinsic evidence and, as such, the claim construction was not erroneous. As a result, the court affirmed the district court’s final judgment of noninfringement of the Asserted Patents.

The Case is No. 23-1269.

Judge: Reyna, J.

Attorneys: William Peterson Ramey (Ramey LLP) for Stylwan IP Holding, LLC. Christopher McKeon (Saunders McKeon PLLC) for Stress Engineering Services, Inc.

Companies: Stylwan IP Holding, LLC; Stress Engineering Services, Inc.

Cases: Patent FedCirNews