5 seconds of contact time is sufficient, says Arnold J

A decision of Mr Justice Arnold issued this week in the Patents Court. It’s a mostly straightforward case of patent infringement and validity in the field of catalysts for hydrocarbon conversion, but containing couple of interesting points on correction and amendment. The decision is Compactgtl Ltd v Velocys Plc & Ors [2014] EWHC 2951 (Pat).

The patentee requested two categories of amendment, one being a correction of an allegedly obvious error and the other being the addition of dependent claims as a precautionary fallback position.

The first amendment
Mr Justice Arnold held patents
valid when amended, and infringed
There were two patents in suit, each of which would have been invalid for insufficiency if unamended, because the independent claims erroneously specified a “residence time” of less than 5 seconds. It had apparently been intended to specify instead a “contact time” of less than 5 seconds (these being different metrics of how long the reagents were in contact with the catalyst). If amended to specify the contact time, then the claims would be sufficient. The examples “did not come close” to teaching how to achieve such short residence times, which expert evidence indicated would be “astonishing”, but there were examples in the patents in which contact times were below 5 seconds.

While the two times can be converted to one another, the values of residence time and contact time would be quite different. For example, the examples included a contact time of 3 seconds which would equate to a residence time of 35 seconds, while a contact time of 1 second equated to a residence time of 12.5 seconds.

The judge held that the standard for correction should be the same as for corrections at the EPO under Rule 139 (formerly Rule 88) EPC, following Mölnlycke Health Care AB v Wake Forest University Health Sciences [2009] EWHC 2204 (Pat) at [137]-[150] and Enlarged Board Decision G11/91.

The judge found that while he preferred the expert evidence of the patentee’s witness (a Dr. Brophy, no relation to any member of the IPKat team), this was not determinative:

Accordingly, to the extent that the issue is one for expert evidence, I have no hesitation in preferring Dr Brophy's evidence. It seems to me, however, that it is a question of interpretation for the court reading the specifications through the eyes of the skilled person.

The judge backed up this conclusion with a point by point analysis of the arguments put forward in favour and against the contention that there was an obvious error. Most of these points were technical in nature and left the judge in no doubt that (i) an error existed, and (ii) it was obvious what the correction ought to be. The only point of the analysis that seemed unorthodox (and this was a minor point and not determinative) arose out of the fact that there was another clear and innocuous error in the specification, namely a mistaken reference to Fig. 1 where Fig. 2 was intended:

92.          A final small point is that, as noted in paragraph 56 above, it is common ground that the specifications do contain a different obvious mistake, namely the erroneous reference to Fig.1 instead to Fig. 2. In my view this would confirm to the skilled reader that the specifications had not been drafted with the utmost care, and thus encourage him to conclude that the references to a residence time of less than 5 seconds were also mistaken.

This might suggest that a patentee’s client is best served when drafting a specification by introducing a small number of errors on which nothing will turn. If this supports the conclusion that the specification was not drafted with the utmost care, then a subsequent correction may be easier to obtain.

The application to correct “residence time” to “contact time” was allowed, restoring validity to the claims.

The second application
By the second application, the patentee sought to introduce new dependent claims to provide alternative fall-back positions if the independent claims were invalid. The new dependent claims specified contact times of “less than about “less than about 2 seconds” and “between 0.1 and 1 seconds”.

As the judge noted, conditional applications to amend in this way were common practice, where the main claims were invalid. The question was whether such an amendment would be allowable if the independent claims were valid, i.e. the new dependent claims were not actually required to restore validity.

The judge held as follows:

104.          Counsel for Velocys [the patentee] argued, however, that Velocys should be permitted to make these amendments even if claims 1 and 9 were found to be valid. I do not accept this. As counsel for Velocys accepted, Velocys would not be able to make such amendments in the context of EPO opposition proceedings by virtue of Rule 80 of the EPC Implementing Regulations: see T 993/07 Fisher-Rosemount/Field device management system (unreported, 20 May 2010) cited in Case Law of the Boards of Appeal of the European Patent Office (7th edition) at p. 899. The same principle has been applied to applications to amend under section 75 of the 1977 Act: see Sara Lee Household & Body Care UK v Johnson Wax Ltd [2001] FSR 17 and DataCard Corp v Eagle Technologies Ltd [2011] EWHC 244 (Pat) at [226].

105.          Counsel for Velocys suggested that these decisions were inconsistent with the earlier case of Norling v Eez-Away (UK) Ltd [1997] RPC 160. I do not accept this. There is nothing in the report of that case to suggest that the nature of the amendment application was merely to add new subsidiary claims. It is true that the defendant had abandoned its validity attack, but the amendment application had been made in response to that attack and it may be inferred that the patentee was concerned that there was substance in it. In any event, section 75 has subsequently been amended so as to introduce subsection (5). This now requires the court when exercising the discretion to amend to have regard to the principles applicable under the EPC. This supports the approach adopted in Sara Lee and DataCard: see Zipher Ltd v Markem Systems Ltd [2008] EWHC 1379 (Pat), [2009] FSR 1 at [205]-[211] (Floyd J, as he then was).

106.          Counsel for Velocys also suggested that Velocys could make such amendments by way of a request to the EPO for limitation under Article 105a EPC, and accordingly submitted that the court should allow Velocys to achieve the same result by an amendment under section 75. I do not accept this, for the simple reason that inserting the new claims as subsidiary claims would not amount to a limitation of the Patents.

107.          The only substantive objection to the amendments is a clarity objection raised by the Intellectual Property Office to new claim 2 of 508 and new claim 10 of 509. The objection is that the word "about" makes the boundary of the claim unclear. CompactGTL did not actively support this objection, no doubt recognising that the wording is firmly based on the specifications at [0035]. It was not suggested to Dr Brophy that the skilled person would have any real difficulty in interpreting these claims, nor did Dr Mauldin suggest this. I agree with the IPO that the use of the word "about" in relation to a numerical limit is undesirable, but in the present case I am not persuaded that the resulting claims are sufficiently lacking in clarity to make the amendments unallowable.

108.          For these reasons I would allow Velocys' second application if it was necessary for Velocys to amend the Patents because claim 1 of 508 and claim 9 of 509 were invalid, but not if those claims are valid.

With the amendment issues out of the way (allowing the correction, but refusing the new dependent claims as unnecessary), the judge then worked his way through the prior art, finding the claims to be novel and inventive, and then infringement, which again went in favour of the patentee.
5 seconds of contact time is sufficient, says Arnold J 5 seconds of contact time is sufficient, says Arnold J Reviewed by David Brophy on Wednesday, September 24, 2014 Rating: 5


  1. I must admit that I've felt on occasions that sometimes the EPO is more lenient on added matter when the specification is drafted badly. I don't know if it somehow affects the Examiner's baseline for what adds matter or if it makes he/she feel sorry for the applicant in some way.

    Arnold it tempting fate though to write what he did in para 92. That cannot be the basis of a test.

  2. What I find problematic in the decision is that (if I understood the technical background correctly) the correction which was finally allowed has the effect of expanding the scope of protection of the patent, because it essentially amounts to a broadening of the claimed range, contrary to Art. 123(3) EPC (or Art. 138(1)(d) EPC in national proceedings). I am not aware if there is UK case law on the relation between (the national provisions equivalent to) Art. 123(3) EPC and R 139 EPC, but EPO case law seems to indicate that such a correction would not have been allowed post-grant (see T195/09). Such a conclusion also makes more sense to me (in the EPC framework, at least), as the Rule providing for corrections is hierarchically subordinate to the Articles (Art. 164(2) EPC).

  3. I think Arnold may have unwittingly thrown a spanner in the works here. The claims are supposed to be interpreted as what the skilled person would think the author meant. So if there is an obvious error, the claim should be interpreted as if the error was corrected - it wouldn't be an obvious error if the skilled man thought the author meant it. So if the corrected patent is sufficient, the uncorrected one must be as well.


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