Corus UK Ltd v Qual-Chem Ltd

For added matter, the question is whether a skilled person, reading the amended specification, would learn anything about the invention that could not be learned from the application as filed. The comparison must address explicit and implicit disclosure in both specifications and be made without hindsight. A disclosure of treating slag alone may be present where the specification’s context makes that teaching clear.

In construing a claim, a word such as tailored can limit the claim while meaning pressure chosen or arrived at to achieve the required result. It does not necessarily require pressure-adjustment apparatus. Variable pressure can satisfy the limitation where it was selected and works for the process.

Corus UK Ltd appealed from the judgment of HHJ Fysh QC in the Patents County Court, reported at [2008] EWPCC 1. The judge held that Qual-Chem Ltd’s amended patent No 2,363,635 was valid and infringed.

On appeal, Corus relied on two issues: non-infringement concerning the requirement that conveying-gas pressure be tailored to the additive, and invalidity under s.72(1) (d) of the Patents Act 1977. The central questions were whether the amended specification disclosed added matter by expressly claiming treatment of slag alone, and whether the pressure used in the alleged process satisfied the claim limitation.

The appeal was dismissed. Lord Justice Jacob gave the first judgment, and Lord Justice Pill and Lord Justice Scott Baker agreed.

1. Added matter. Article 123(2) of the European Patent Convention supplied the relevant test. The court compared the explicit and implicit disclosure in the application as filed with that in the amended specification, without hindsight. The question was whether the skilled person would learn anything about the invention from the amendment which could not be learned from the original disclosure. The court referred to the recent summaries in European Central Bank v Document Security Systems [2008] EWCA Civ 192 and Vector v Glatt [2007] EWCA Civ 805, and applied the principles associated with Bonzel v Intervention and Richardson-Vicks Patent [1995] RPC 568.
2. The application as filed disclosed treatment of slag alone. In context, “molten iron” could include the liquid iron with its supernatant slag. The specification referred to penetration through slag, reaction with slag, particles remaining in slag rather than descending into the iron, slag killing, calcium carbonate and slag-conditioning additives. The added-matter challenge therefore failed.
3. Infringement. The words “being tailored” were words of limitation and could not be ignored: Step v Emson [1993] RPC 513. Applying the skilled-person approach in Kirin Amgen v TKT [2005] RPC 9, the term meant pressure so arrived at or chosen as to produce the required effect. It did not require pressure-adjustment apparatus or continuous adjustment. A variable pressure selected because it worked could satisfy the limitation. The pressure used at Corus therefore fell within the claim.
4. The court did not need to resolve the suggested distinction between added matter and loss of priority. It also indicated that the specific unpleaded and unevidenced version of the added-matter argument would not have been allowed to be taken on appeal.

1. Court of Appeal (Civil Division): Corus UK Ltd’s appeal was dismissed.
2. Patents County Court: HHJ Fysh QC held that Qual-Chem Ltd’s amended patent No 2,363,635 was valid and infringed in the judgment reported at [2008] EWPCC 1.