T 0551/90 14-04-1992

1. All three appeals meet the requirements of Articles 106 to 108 and Rules 1(1) and 64 EPC. They are therefore admissible.

2. Allowability of the amendments

In Decision T 169/83 (supra), which has been relied upon by the Appellants, it was found after detailed consideration of various provisions of the EPC that in deciding whether the inclusion of features from a drawing into a granted claim was allowable it was only necessary to consider whether the amendments made contradicted the legal principles of Articles 123(2) and (3) EPC (see point 4.4 of the grounds).

According to this decision, see points 3.5 to 3.7 of the grounds, the requirements of Article 123(2) EPC are to be seen as being met if the features involved are clearly, unmistakeably and fully derivable from the drawings as regards their structure and function and in no way contradict the other parts of the disclosure. This view has been confirmed by a number of subsequent decisions (e.g. T 443/89 and T 308/90, both not published) and now forms part of the established jurisprudence of the Boards of Appeal.

Valid Claim 1 includes three groups of features that have to be analysed for their conformity with the conditions set out above. These are:

(1) the arrangement of the membrane.

(2) The presence and form of wall means between the impeller chamber and the collecting chamber.

(3) The disposition of the conduits.

(a) It is clear from Figure 1 of the drawing that the membrane lies substantially in a plane which coincides with the section line III-III, this line being perpendicular to the longitudinal axis of the pump and the impeller of the pump being arranged along this axis. In other words it can be seen that the membrane lies in a plane substantially perpendicular to the axis of the impeller as is now stated in present Claim 1. Implicit support for this statement can also be found in the original description at page 5, paragraph 2, where it is indicated that the manifold or collecting compartments have their axes parallel to that of the impeller housing, it being clear from the drawing that the membrane is arranged substantially perpendicular to the axes of these compartments.

(b) Although granted Claim 1 does not specifically mention the presence of wall means between the impeller chamber and the collecting chamber it is evident that such wall means must be provided if the pump is to function so that this feature can be considered as being implicit in the granted Claim 1. As can be clearly seen in the view of Figure 3 the side of the wall means facing the impeller chamber forms a smooth streamlined continuation of the circular inner surface of that chamber, as stated in present Claim 1. As pointed out by the Appellants Figures 1 and 3 of the drawing are inconsistent as to whether the wall means are integral with the impeller housing or constituted by separate elements located in the housing. In the opinion of the Board this inconsistency cannot however detract from the unambiguous teaching of Figure 3 with regard to the form of the wall means, it being irrelevant in this respect whether the wall means are integrally formed with the housing or not.

(c) It was stated in the original disclosure that the conduits are arranged tangentially to the impeller chamber. According to present Claim 1 this statement has been amplified to indicate that one conduit lies above and one below the plane of the membrane and that the conduits extend towards the central area of the membrane when viewed in a direction perpendicular to that plane. Support for the location of the conduits on respective sides of the membrane is to be found not only in the drawing but also in the original description at page 6, lines 15 to 20 according to which one conduit opens into the upper half of the impeller chamber and one into the lower half. Since it is clear from Figure 1 of the drawing that the plane of the membrane substantially bisects the impeller chamber in the axial direction thereof it is evident that one conduit must lie above this plane and one below. The fact that the conduits extend towards the central area of the membrane is unmistakeably shown in the view of Figure 3 which is along a direction perpendicular to the plane of the membrane, thus corresponding to the wording of Claim 1 in this respect.

The Appellants accept that the disposition of the conduits as now defined in Claim 1 can be derived as such from the drawing but argue in effect that the relevant features incorporated into the claim are an arbitrary selection among those possible so that an unallowable intermediate generalisation has been made. In particular, they say that the claimed disposition of the conduits has only been disclosed in combination with an impeller which has an axial extent twice that normally used, and that it should be specified that the conduits are disposed completely on one side or the other of the plane of the membrane. The Board is however satisfied that there is no strict requirement for the impeller to be of any particular axial extent, as demonstrated by a sketch presented by the Respondents in which a normal impeller is used. Furthermore, the fact that each conduit is disposed completely on a respective side of the plane of the membrane is in any case implicit since no other arrangement would make any technical sense. This view was explicitly confirmed by the Respondents at the oral proceedings.

Accordingly, having regard to the above detailed considerations, the Board comes to the conclusion that the amendments made to Claim 1 do not offend against the requirements of Article 123(2) EPC. Furthermore, in the present case the requirements of Article 123(3) EPC pose no problem since valid Claim 1 contains all the features of granted Claim 1 and has clearly been restricted by the inclusion of the features involved. This being the case, no lateral shifting of the scope of protection has occurred, as has been alleged by the Appellants. The amendments are therefore allowable.

The Board cannot find any justification in the provisions of the EPC for the contention of the Appellants that the allowability of the amendments is also conditional on a further requirement, namely that it must have been immediately apparent to the skilled man from the original disclosure that these features contributed to the solution of the technical problem as presented therein. Contrary to the assertions of the Appellants, their contention is not supported by the reasoning of Decision T 169/83, upon which they have relied in this respect. Instead, as indicated in point 4.5 of the grounds of that decision, it is permissible during opposition proceedings to establish which features are essential to the solution of the problem and to include them in the claims.

The amendments made to the dependent claims and description are restricted to those necessary to bring these into agreement with new Claim 1. Since the claims and description of the granted patent do not contain any unallowable amendments with respect to the original application documents it follows that there are no formal objections to the documents corresponding to the request of the Respondents as submitted at the oral proceedings.

3. State of the art

The closest state of the art, on which the preamble of Claim 1 is based, is shown in Figure 5 of document D2. This prior art pump comprises a bellows-like membrane which is supported at one side of the impeller chamber in a plane which contains the axis of the impeller. The support for the radially inward side of the membrane is located within the impeller chamber and has a substantially "T"-shaped cross-section the bar of the "T" defining with the wall of the impeller chambers short conduits which depending on the direction of rotation of the impeller direct a flow of liquid against one side or the other of the membrane. The membrane can move between two valve seats provided on respective opposed ends of two delivery outlet ducts.

Document D1, which is mentioned in the introductory description of the patent specification, relates to a dual delivery pump with a change-over valve member that is frictionally coupled to the impeller shaft and moved thereby against a valve seat on one or other of the delivery ducts.

Document D6, which is also mentioned in the patent specification, shows a dual delivery pump which instead of valve means utilises fixed vanes which direct the flow to one outlet or the other depending on the direction of rotation of the impeller.

Documents D4, D5 and D8 are essentially equivalent and show a bidirectional pump which is associated with a membrane type valve constituting an element which is separate from the pump.

In document D7 there is disclosed a dual delivery pump wherein respective membrane valve members are associated with valve seats provided at the ends of two conduits which enter the impeller chamber tangentially at opposite sides thereof. The two membrane valve members are functionally coupled by means of either a lever or a hydraulic link so that one will open when the other closes.

Document D3 relates to a general purpose valve with a membrane valve member.

4. Novelty

It is apparent from the above discussion of the state of the art that the subject-matter of present Claim 1 is novel. It is distinguished from the pump disclosed in Figure 5 of document D2 by the features specified in the characterising clause of the claim. Since novelty has not been at issue in the appeal proceedings further detailed elucidations on this point are unnecessary.

5. Inventive step

5.1. The Appellants have contested that the main technical problem as stated in the patent specification, which is to provide a pump having reduced power and pressure losses, is solved by the claimed construction. Although it was at the disposal of the Appellants to prove this contention by means of an appropriate comparative test they have instead attempted to demonstrate it by a theoretical calculation of the pressure losses to be expected with a pump as claimed in comparison with the prior art pump of document D2. They have not however succeeded in doing this to the satisfaction of the Board. The calculations presented at the oral proceedings assume a complex path for the liquid being discharged from a pump according to the invention and sums together the pressure loss coefficients to be expected along this path. It is however apparent that at least a significant proportion of the liquid would not follow such a path but would instead pass directly from the exit of the conduits to the valve seat without being required to travel around or up the wall of the valve seat before being discharged. Furthermore the calculation includes as a significant component a pressure loss coefficient for a bend in the discharge duct which strictly speaking has nothing to do with the valve mechanism as such. When considering the prior art pump of document D2 the calculation assumes on the other hand that there is a simple reversal of flow in front of the membrane which given the practical construction involved seems somewhat unlikely. Furthermore, as pointed out by the Respondents, the Appellants have ignored the fact that the prior art pump would be made inherently inefficient due to the positioning of the membrane support within the impeller chamber necessitating a reduction in the diameter of the impeller.

5.2. The comparative test actually submitted by the Appellants is manifestly unsuitable for proving their allegations in the above respect since firstly, it is not clear whether the pump purported to conform with the invention actually does so with regard to the disposition of the conduits, secondly, the reference pump does not conform with the prior art shown in document D2 but is clearly superior thereto, and thirdly, the membranes utilised in the two pumps have different forms and are associated with valves having different clearances.

5.3. The further reasons advanced by the Appellants which in their opinion would lead to inefficient operation of the pump according to the invention, namely increased turbulence in the impeller chamber due to its doubled axial length and poor sealing of the edge of the membrane in the region of the conduits do not seem plausible to the Board and remain as purely unsubstantiated allegations.

5.4. Taking the above into account the Board is therefore satisfied that the technical problem of providing a simple, reliable dual delivery pump which functions efficiently with low power and pressure losses has been solved by a pump having the features specified in present Claim 1.

5.5. The principal attack of the Appellants on the inventive step of the claimed subject-matter was based on their allegation that the arrangement of the membrane did not contribute to the solution of the stated problem and accordingly, in their view, had to be ignored when assessing patentability. As shown above, however, this allegation has not been proved so that this attack must fail. It is in any case, in the opinion of the Board, based on a misconception of how the objective problem and solution approach, which according to the established jurisprudence of the Boards of Appeal is the one to be adopted when evaluating inventive step, operates. Be that as it may, the Appellants also advanced the view that the construction defined in Claim 1 would be arrived at by the skilled man in the exercise of routine considerations in respect of simplicity of moulding of the pump components and their subsequent assembly. The Board can find no basis for this in the prior art. Of the documents cited only two, that is D2 and D7, relate to a dual delivery pump in which membrane valve means are incorporated into the pump housing structure. In both of these documents the membrane or membranes are arranged in a plane which contains or is parallel to the axis of the impeller and the conduits leading from the impeller chamber to the collecting chamber extend substantially perpendicularly to the plane of the membrane. A corresponding perpendicular arrangement of the input ducts with respect to the plane of the membrane is also to be found in the membrane type valves disclosed in documents D3, D4, D5 and D8. It was only after the Respondents had decided to place the membrane in a plane perpendicular to the axis of the impeller with the conduits extending generally parallel to that plane, for which there is no counterpart in any of the prior art documents, that they could reap the benefits associated therewith as regards the simple manner in which the membrane can then be mounted between the cover and the body of the pump housing.

5.6. Accordingly, the Board comes to the conclusion that the subject-matter of Claim 1 as submitted at the oral proceedings cannot be derived in an obvious manner from the state of the art and therefore involves an inventive step (Articles 52(1) and 56 EPC). This claim, together with Claims 2 to 5 dependent thereon and the amended description and drawing also submitted at the oral proceedings, are therefore a suitable basis for maintenance of the patent in amended form.

6. Unity of invention

As pointed out by the present Board in an earlier decision T 101/88 (not published) there is no provision in the EPC requiring that unity of invention must exist between the subject-matter of a valid Claim 1 and an earlier version thereof so that the arguments presented by the Appellants in this respect do not need to be considered. For this reason, and since it was foreseeable that a decision of the Enlarged Board of Appeal in the matter G 1/91 would issue before the date appointed for oral proceedings in the present case, the request for a stay of the proceedings in the present case was refused. Decision G 1/91 of the Enlarged Board of Appeal was in fact issued on 9 December 1991 (Headnote published in OJ EPO 1992/03). In it was decided that unity of invention was not an issue that could be considered in opposition proceedings.

7. Reimbursement of appeal fee

The request of the second Appellants was supported solely by a reference to Decision T 73/88 (supra). A question of law arising from this decision was subsequently referred to the Enlarged Board of Appeal which by its Decision G 2/91 of 29 November 1991 (Headnote published in the OJ EPO 1992/01-02) established that an appeal fee cannot be refunded for the only reason that there was already another appeal in existence.

The request for reimbursement of the appeal fee must therefore be refused.