Compactgtl Ltd v Velocys Plc & Ors

In patent amendment proceedings, an obvious mistake may be corrected where the skilled person would immediately recognise both the error and the precise correction. The court must read the specification as a whole, using common general knowledge, but may not use correction to introduce a different invention.

Claims directed to a contact time could therefore be amended where the specification consistently addressed contact time, while isolated references to residence time were inconsistent with the examples and technical teaching. A patent claim is construed according to the language of the claim. A structure may be porous because of its configuration, even if the material from which it is made is not itself porous. A buffer layer is not restricted to the manufacturing methods disclosed in the specification.

Velocys sued CompactGTL for infringement of European Patents (UK) Nos 1 206 508 and 1 206 509, relating to structured catalysts for Fischer-Tropsch synthesis. CompactGTL denied infringement and challenged validity on amendment, insufficiency, novelty and obviousness grounds.

Velocys applied to amend references to residence time to contact time and sought additional fall-back claims. The court also had to construe porous structure, porous support and buffer layer, assess novelty over Hunter and Schanke, and determine infringement by CompactGTL’s pilot-plant catalyst structure and process.

1. Amendments. The references to residence time of less than five seconds were obvious mistakes. The skilled person would recognise from the specification as a whole that contact time was intended. The claims and description could therefore be corrected under the principles applicable to G11/91 CELTRIX/Correction of errors [1993] EPOR 245. The first amendment application was allowed.
2. The proposed additional subsidiary claims could be introduced only conditionally, if the principal claims were invalid. The second application was therefore unnecessary and was refused. The objection to the word “about” did not make the proposed claims insufficiently clear.
3. Construction. “Porous structure” and “porous support” referred to the structure or support, not necessarily to the material before formation. A metal honeycomb or foam could therefore satisfy the requirement. A buffer layer had to be distinct from the porous support and interfacial layer, but the claims imposed no restriction to vapour deposition or solution coating. Oxidising an underlying metal layer could produce the buffer layer. “For” Fischer-Tropsch synthesis meant suitable for that purpose, not merely capable of producing some hydrocarbons momentarily.
4. Validity. Claim 1 of patent 509 was novel over Hunter because Hunter did not disclose a structure suitable for Fischer-Tropsch synthesis or the specified catalyst metals. Claim 1 of patent 508 was novel over Schanke because, on the proper calculation including the space surrounding the catalyst, the disclosed contact time could be 5.2 seconds, which was not less than five seconds. None of the claims was obvious over Schanke. The skilled person would approach it sceptically, its results were underwhelming, and the proposed route to a Fecralloy catalyst with a buffer layer depended on unsupported assumptions and research.
5. Infringement. CompactGTL’s corrugated and arced pre-oxidised foil structure was porous, its alumina surface was a buffer layer, and its manufacturing process satisfied the relevant claim language. It infringed claims 1 and 6 of patent 508 and claims 1, 7, 9 and 16 of patent 509.