T 0555/98 (Gas separation/L'AIR LIQUIDE) 15-02-2002

I. This appeal is from the decision of the Opposition Division, dated 5 May 1998, to revoke European patent No. 0 266 271 for a third time. The decision was based on the ground that the patent proprietor (Appellant) had failed to submit a text in which the European patent could be maintained.

II. The two previous decisions of the Opposition Division to revoke the patent were set aside by the then competent Board of Appeal 3.4.2. With its first decision T 1027/93, the Board remitted the case to the Opposition Division for further prosecution. With its second decision T 367/96, the Board decided that the case be remitted to the first instance with the order to maintain the patent in amended form on the basis of the claims filed as the Appellant's fourth auxiliary request (filed as "Patentee's Fifth Request" during the oral proceedings of 3 December 1997 before the Board and hereinafter referred to as "the Fourth Auxiliary Request"), with the description and drawings to be adapted, where necessary.

III. Claim 1 of the Fourth Auxiliary Request reads:

"1. A fermentation process wherein the off-gases is comprised of a gas mixture, comprising the steps of

providing a semipermeable membrane having a feed gas side and a sweep gas side,

contacting said feed gas side of said semipermeable membrane with a feed gas mixture comprising said off-gases, said feed gas mixture containing two gases to be retained which gases are present on said sweep gas side, and at least one gas to be separated therefrom,

simultaneously contacting said sweep side of said semipermeable membrane with a sweep gas having a pressure lower than that of said feed gas,

withdrawing a residue gas after contact with said feed side of said membrane which is substantially depleted of said gases to be separated,

withdrawing a permeate gas after contact with said sweep side of said membrane which is substantially enriched with said gases to be separated,

characterized by further comprising:

balancing said partial pressure of a first gas to be retained to provide as close as possible substantially equal partial pressures on both sides of the membrane while at the sane (read "same") time providing a partial pressure differential across the membrane for a second gas to be retained, which partial pressure differential is less than the partial pressure differential of said gas to be separated to maximize diffusion across the membrane of said gas to be separated while minimizing diffusion across the membrane of said gases to be retained."

IV. Subsequently, the Opposition Division sent out an invitation for the Appellant to file an adapted version of the description, and the Appellant, in a letter of response dated 10 April 1998, explicitly disagreed. It submitted that the decision T 367/96 was based on an obvious mistake consisting in an erroneous interpretation of the prior art, namely a wrong calculation of the partial pressure which contradicted the laws of physics. The Appellant asked the Opposition Division to correct under Rule 89 EPC the obvious mistake made and to reissue an appealable decision on non-obviousness. It further indicated that, in case of disagreement by the Opposition Division, it would like to join the case J 3/95 pending before the Enlarged Board of Appeal as G 1/97 in order to learn how to obtain a revised decision where a procedural mistake was an obvious mistake.

The Appellant did not propose any text for adaptation of the description to the claims of the Fourth Auxiliary Request.

V. Thereafter the Opposition Division rendered said third decision mentioned under I. above, against which the Appellant, on 8 June 1998, lodged its present and third appeal and paid the appeal fee. In a letter headed "Grounds of Appeal Statement" filed on 2 September 1998, the Appellant essentially repeated its arguments and requests submitted to the Opposition Division (see IV. above) but proposed, as an alternative to join case J 3/95, to wait for the issuance of opinion G 1/97. In addition, the Appellant requested - as its last auxiliary request - to be given another opportunity to accept the claims of the Fourth Auxiliary Request.

VI. In a letter dated 10 December 1998, the Respondent (Opponent) submitted that the "appeal must be rejected" since none of the alleged grounds of appeal addressed the only ground on which the patent was revoked, namely that there was no text in which the patent may be maintained, and since the decision of the Board of Appeal was final and not open to further appeal. It requested that the appeal be dismissed as inadmissible and that an award of costs of the present appeal proceedings be made in favour of the Respondent.

VII. Due to a change of business distribution scheme of the technical Boards of Appeal, this appeal was allocated under case number T 555/98 to the present technical Board 3.3.5 which stayed the proceedings until the issuance, on 10 December 1999, of the decision of the Enlarged Board of Appeal in the case G 1/97 (OJ, EPO 2000, 322) in order to comply with the Appellant's respective request (see V. above).

Following the opinion given in G 1/97, the Board, in a letter dated 12 May 2000, communicated its preliminary opinion that the present Board had no competence to revise a decision given by another Board, and further that the competence to correct an appeal decision under Rule 89 EPC lies with the Board which has given the decision, as was established by the Enlarged Board of Appeal in its opinion G 8/96. Finally, the Board did not see any reasons justifying an award of costs as requested by the Respondent.

VIII. In order to comply with the Appellant's respective request (see IV. and V. above), oral proceedings were held before the Board on 26 January 2001, in the absence of the Respondent (Opponent) as announced by a letter of 28 July 2000. These proceedings were terminated with the decision to continue the proceedings in writing to give the Appellant, upon its request, the opportunity to submit the case to the Board of Appeal 3.4.2 which has given decision T 367/96 (see communication of Board 3.3.5 dated 6 March 2001).

IX. Accordingly, the Appellant in a letter dated 27. February 2001 requested that Board 3.4.2 correct under Rule 89 EPC an obvious mistake present in the decision T 367/96 issued on 3 December 1997.

In its decision dated 21 June 2001, Board of Appeal 3.4.2 decided to refuse this request since the correction did not relate to an error or mistake open for correction under Rule 89 EPC.

X. In a communication dated 11 July 2001, Board 3.3.5 invited the Appellant to present its ultimate requests in respect of the still pending appeal T 555/98 and to submit a description adapted to the claims of the Fourth Auxiliary Request declared patentable in decision T 367/96.

XI. With a letter submitted by telefax on 11 September 2001 (dated 19 July), the Appellant filed an amended version of the description "adapted to the fourth auxiliary request as granted in decision T 367/96, as earlier requested, for further grant of a modified patent, if there is no possibility to obtaining a fair treatment of this case".

In a communication dated 31 October 2001, the Board informed the parties of its intention to maintain the patent in amended form on the basis of the claims according to the Fourth Auxiliary Request with the proviso that further amendments to the description of the patent in accordance with the Board's proposal were filed or agreed to within the time period given. The Appellant, in a letter of reply of 27 November 2001, gave its agreement. The Respondent informed the Board by a letter dated 7 December 2001 that he had no further comments.