In re Clay

Clay's (appellant) patent application claimed a process for storing and removing petroleum products using a dead volume apparatus in an above-ground storage tank; the patent examiner rejected the claims as obvious over two references, including Sydansk, which involved gels used in underground crude oil mining to assist extraction under extreme conditions, and the Board of Patent Appeals and Interferences upheld the rejection before Clay appealed to the Federal Circuit.

Whether prior art must be from the same field of endeavor as the claimed invention, or relevant to the specific problem the inventor sought to solve, to be considered analogous art supporting a claim rejection.