The US Court of Appeals for the Federal Circuit found that a commercial sale did not qualify as a “public disclosure” under 35 U.S.C. § 102(b)(1)(B) where the sale did not make the relevant aspects of the invention available to the public. NCS Multistage Inc. v. Nine Energy Service, Inc., Case No. 25-1000 (Fed. Cir. Sept. 14, 2026) (Cunningham, Reyna, Hughes, JJ.)
NCS Multistage sued Nine Energy Service for infringing claims of a patent directed to a “float tool” used in the oil and gas industry to help run casing strings to the bottom of a wellbore. The claimed invention uses a rupture disc to seal the casing during installation and rupture once the casing is positioned, avoiding the need to drill out plugs.
At trial, Nine argued that a prior-art device (the TDP-PO tool, which a third party, TCO, sold to Apache in August 2012) anticipated the asserted claims. NCS responded that its own earlier sale of an AirLock device to Tundra in July 2012 constituted a “public disclosure” under § 102(b)(1)(B), thereby removing the later Apache sale from the prior art. The jury returned a verdict in favor of NCS on both infringement and no invalidity. Nine appealed.
The Federal Circuit disagreed with NCS, concluding that the AirLock sale was not a public disclosure as a matter of law. Relying on its 2024 decision in Sanho Corp. v. Kaijet Technology Int’l Ltd, Inc., which interpreted the same “publicly disclosed” language in § 102(b)(1)(B), the Court explained that placing an invention “on sale” does not necessarily mean that the invention has been publicly disclosed. NCS privately sold the AirLock to a single customer. The device was delivered inside a sealed black tube that had to be cut open to inspect its internal components. There was no evidence that receipt of the tube made the claimed features available to the public, including the rupture disc’s configuration and its relationship to the casing string’s internal diameter. Although the transaction was not subject to a nondisclosure agreement, there was likewise no evidence that the invention’s relevant features were communicated beyond Tundra, and NCS’s own technical materials were marked confidential. On those facts, the Court concluded that the AirLock sale did not qualify as a public disclosure under § 102(b)(1)(B).
The Federal Circuit also reversed two claim construction rulings. First, it found that the term “internal diameter” has a single meaning (i.e., a measured diameter across the width of the casing string) and rejected the district court’s construction permitting the term to refer either to that measurement or to an inner surface. Second, the Court found that the term “casing string” should not be limited to casing measuring at least 4.5 inches because the specification’s permissive language did not establish either lexicography or disavowal.
The claim construction errors, together with the erroneous treatment of the AirLock sale, required a new trial on infringement and invalidity. Accordingly, the Federal Circuit vacated and remanded for further proceedings.
Practice note: Patent owners seeking to invoke § 102(b)(1)(B)’s safe harbor against intervening third-party prior art should ensure that their earlier disclosure actually makes the relevant features of the invention available to the public. A commercial sale to a private customer, standing alone, may not be enough.
