T 0462/01 03-06-2003

Reasons for the Decision

1. Priority right and novelty of claim 1

1.1. The subject-matter of contested claim 1 includes apparatus for reducing hydrocarbon emissions from the fuel storage tank, which comprises a filter membrane having the property of permitting hydrocarbon vapours to permeate therethrough. The only aspect of the right to priority which has been challenged is that relating to the property of permeability to hydrocarbons of the filter membrane and so the Board need consider only this aspect.

1.2. The relevant disclosure of D8 (the priority document) begins on page 4 under the heading "Summary of the Invention". Here it is explained that a chamber containing a fractionating membrane is mounted in the vent line of a fuel storage tank and that a mixture of air and fuel vapour in the vent line passes into the chamber. Air is allowed to pass through the chamber and the vapour is drawn through and captured by the membrane. In the preferred embodiment the membrane is configured as a cylinder having an aperture therein disposed axially from end to end, within which is located a perforated drain pipe through which condensed vapour is returned to the tank. In claims 1 and 7 of D8 the membrane is described as being capable of transporting the vapour therethrough whereby fuel exits through the drain whilst air passes across the membrane. In the description of the preferred embodiment the membrane is disclosed as being preferably a fractionating membrane developed by GKSS-Forschangszentrum Gesthacht GmbH (sic) and described in two papers presented at conferences by Mr K. Ohlrogge (cf. D9), which papers are incorporated by reference. As can be derived from the above summary, it is clear upon reading D8 that the vapour passes through from one side of the membrane to the other and therefore that it permeates the membrane. However, throughout D8 there is also reference to condensation of the vapour by the membrane, whereby the fuel returns in liquid form to the tank. Moreover, in the sentence bridging pages 7 and 8 it is stated that the membrane "will capture or collect ... hydrocarbons ... while allowing air to pass through" which, in the appellant's view is a disclosure that the membrane allows only air to permeate. The appellant therefore considers that the disclosure of D8 when taken as a whole cannot be regarded as a disclosure of a membrane which allows permeation of vapour.

1.3. The paragraph bridging columns 4 and 5 of the specification of the contested patent contains wording essentially identical to that used in D8 page 7, lines 14 to 26 and incorporates by reference the disclosures by Mr K. Ohlrogge at two conferences (cf. D9) that the membrane of the filter can be a fractionating membrane as defined in those papers. It is clear to the skilled person when considering, for instance, Figure 6 of D9, which relates to a vapour recovery system for use when dispensing petrol to motor vehicles, that the membrane allows vapour to permeate since the line 10 which is separated from the inlet to the chamber by the membrane and returns petrol to the storage tank is designated as the permeate line. For this reason alone D8 provides a clear disclosure of a hydrocarbon vapour permeable membrane. This finding is wholly consistent with the opinion G 2/88 (supra) since the most important disclosure in D8 of a membrane permeable to hydrocarbon vapour, the reference to the papers by Mr K. Ohlrogge, is identical to that in the contested patent and so requires no interpretation as regards identity of invention. Moreover, it is clear to the skilled person when reading D8 that the references to condensation of the vapour cannot mean that the vapour does not permeate the membrane since it otherwise could not reach the drain located in the centre of the cylindrically formed membrane which separates the drain from the inlet to the chamber. As regards the sentence bridging pages 7 and 8 of D8 the reference to through passage of the air could relate either to passage through the membrane or to passage through the chamber and so fails to contradict the above discussed disclosure of permeation. Also, the statement that the membrane acts to "capture or collect" the vapour does not explain whether this capture or collection is outside or inside of the cylindrically arranged membrane. It follows that, contrary to the view of the appellant, also this sentence does not teach that the membrane is permeable to air rather than hydrocarbons.

1.4. The Board therefore finds that claim 1 does enjoy its right of priority (Article 87 EPC). As a result its effective date of filing is 16 November 1993 (Article 89 EPC), D1 and D2 do not form prior art within the meaning of Article 54 EPC and the subject-matter of the claim is novel.

2. Inventive step

2.1. As set out in the introductory description of the contested patent, fuel dispensing systems having vapour recovery means employing a vacuum pump which draws into the recovery line a volume of air/vapour mixture which is greater than the volume of fuel dispensed and in which the storage tank is provided with a vent pipe are well-known. A relatively simple system as described by the respondent during the oral proceedings is essentially a standard fuel dispensing system with additional vapour recovery means arranged between the dispenser and the storage tank. A more complex system is disclosed in D4 or D9, Figure 6, which comprises a filter having a hydrocarbon-permeable membrane essentially as defined in contested claim 1 but wherein the inlet is connected to the vapour recovery line, the first outlet to the vent pipe of the storage tank and the second outlet to the storage tank. Whilst these known systems reduce hydrocarbon emissions during dispensing of the fuel there remains the possibility with both systems of hydrocarbon vapour escaping from the storage tank through the open vent pipe directly to atmosphere. This is particularly the case with the relatively simple system referred to above in which build-up of pressure in the storage tank may be prevented by venting the excess volume to atmosphere, thereby reducing the effectiveness of the vapour recovery. As indicated in the contested patent it had been proposed to burn off vented vapour but the danger of this technique was obvious and it was in any case not permitted in many areas. The subject-matter of contested claim 1, according to which a membrane filter is essentially arranged in the vent pipe, addresses this problem. As confirmed by the respondent during oral proceedings the subject-matter of contested claim 1 does not exclude a membrane filter also in the vapour recovery line as known from D4 or D9, Figure 6, and consideration of inventive step when starting from either of the prior art dispensing systems having vapour recovery means concerns the obviousness of reducing emissions from the vent pipe.

2.2. It is known from D9 that a membrane filter may be used to reduce emissions generated in petrol depots as the result of tank breathing (page 294, penultimate sentence). Although the filters in such applications have a relatively large capacity of up to 1500 m3/h, D9 also discloses that membrane filters may have a capacity as low as 1 m3/h (page 302, penultimate sentence). The Board considers that in the light of this information it would be obvious for the skilled person faced with the need to solve the stated problem in one of the above-mentioned prior art fuel dispensing systems to provide a membrane filter in the vent pipe of the storage tank and thereby arrive at the subject-matter of contested claim 1.

2.3. The Board concludes that the subject-matter of contested claim 1 does not involve an inventive step (Article 56 EPC).

3. Procedural matters

At the conclusion of the consideration of inventive step during the oral proceedings the chairman noted that no amendments had been made to the parties' requests and declared that the debate was closed. The respondent subsequently asked for an opportunity to file an amended request. Article 11(5) RPBA explicitly states that no submissions may be made by the parties after closure of the debate unless the Board decides to re-open it. Since the Board did not re-open the debate the respondent's request was refused in accordance with Article 11(5) RPBA.