T 1828/08 07-12-2011

Reasons for the Decision

1. The appeal is admissible.

2. Main request

2.1 Fresh ground for opposition

The opponent's original opposition was based exclusively on the ground of lack of inventive step under Article 100(a) EPC. The opponent did not include any objection under Article 100(c) EPC. However, in its communication dated 6 October 2005, the Opposition Division introduced a new ground of opposition under Article 100(c) EPC and raised an objection under Article 123(2) EPC against claim 1 as granted. Under Article 114(1) EPC the Opposition Division was entitled to raise this ground of opposition of its own motion (see G 9/91, OJ EPO 1993, 408; point 16 of the Reasons). Under these circumstances, the ground of opposition under Article 100(c) EPC does not represent a "fresh ground of opposition" as defined in G 9/91 (see also G 1/95, OJ EPO 1996, 615; point 5.4 of the Reasons and "Case Law of the Boards of Appeal of the EPO", 6th Ed. 2010, VII.D.3.2.3a)).

Article 100(c) EPC refers to the extension of subject-matter beyond the application as filed (cf. Article 123(2) EPC) or, in case of divisional applications, beyond the content of the earlier application as filed (cf. Article 76(1) EPC). Nevertheless, G 1/95 (point 4.2 of the Reasons) makes it clear that the ground for opposition under Article 100(c) EPC (as well as under Article 100(b) EPC) relates to a single legal basis on which an opposition can be based (in contrast to the collections of different legal bases or grounds of opposition defined in Article 100(a) EPC). Accordingly, the objections raised by the opponent under Article 76(1) EPC in the opposition proceedings do not represent "fresh grounds for opposition". Furthermore, they can be considered in appeal proceedings without the approval of the patentee since, according to G 9/91 (point 18 of the Reasons), such approval is only required for fresh grounds introduced at the appeal stage. The respondent's above-mentioned objections (see first paragraph of point X) were, however, already raised during the opposition proceedings.

2.2 Amendments

Feature [g] of claim 1 refers to "monitoring the conductivity of the partially prepared fluid in said recirculation circuit". This wording merely requires that the partially prepared fluid is located in the recirculation circuit, but leaves it open where the monitoring actually takes place. The Board does not follow the view of the Opposition Division and the respondent that this formulation implies that the monitoring takes place in the recirculation circuit. The term "in the recirculation circuit" grammatically refers back to the term "partially prepared fluid", which immediately precedes it, rather than to the previously used term "monitoring the conductivity". The claim thus fails to specify where the monitoring takes place. Accordingly, the monitoring could also be performed outside the recirculation circuit, e.g. on samples taken therefrom, but this possibility is not disclosed in the parent application as filed. On the contrary, the relevant embodiments shown in Figures 5a and 5b of the parent application both depict the conductivity meter 23a being located in the recirculation circuit 20a, as also stated in the respective text passage in column 7, lines 26 to 29, and in claim 5. As explained in further detail below (see point 3.4) the Board is of the opinion that it is essential for the function of the invention that the monitoring takes place in the recirculation circuit.

Accordingly, the subject-matter of claim 1 of the main request extends beyond the content of the parent application as originally filed in breach of Article 76(1) EPC.

3. First auxiliary request

3.1 Amendments

3.1.1 The Board does not share the appellant's view that feature [f] of claim 1 should mention that the water supply is ended using a valve in order to comply with the requirements of Article 76(1) EPC. Although the preferred embodiment disclosed in the description of the parent application as filed utilises valves, such valves are nowhere described as being essential, nor are they indispensable for the function of the invention. As correctly stated by the appellant, valves are not the only known means for stopping the water supply. Indeed, lines 17 to 25 of column 3 of the parent application indicate that a valve is merely one suitable arrangement for controlling the water supply. The skilled person was aware that other means could also be used. A further indication that valves are not essential is given by the fact that claim 1 of the parent application as originally filed does not mention any valves. It rather covers valves as one possibility within the broad "means for conducting the water to a mixing vessel".

3.1.2 For reasons analogous to those indicated supra, the Board also does not follow the appellant's argument that feature [h] of claim 1 should specify that the recirculation is stopped by switching a three-way valve for conducting the fluid out of the recirculation circuit in order to comply with the requirements of Article 76(1) EPC. Again, such a valve is merely a practically preferable way of embodying the invention. Using a valve for this purpose is not indispensible for the function of the invention, and there is nothing in the parent application as filed that describes this feature as essential.

3.1.3 Finally, there is no need in claim 7 for defining that the uncoupling step is performed with quick-release connectors. Lines 40 to 46 of column 4 and lines 39 to 48 of column 7 of the parent application make it explicitly clear that quick-release connectors are merely preferable. The fact that the mixing vessel is thereby quickly exchangeable is of no relevance for the functioning of the invention.

3.1.4 For the above reasons, the appellant's objections under Article 100(c) EPC with respect to the first auxiliary request are not justified. The Board is satisfied that the requirements of Articles 76(1) and 123(2) EPC are met.

3.2 In view of the above finding, the question whether the Opposition Division properly exercised its discretion under Article 114(2) EPC not to admit the opponent's objection addressed under point 3.1.3 supra can be left aside. Also, it is not necessary for the Board to deal with the respondent's request to remit the case if this objection is regarded as prima facie relevant and thus discussed at the appeal stage.

3.3 Late filed evidence

3.3.1 Document D7

Document D7 was filed late at the opposition stage, namely one month before the oral proceedings before the Opposition Division held on 27 March 2007. Its submission cannot be seen as a response to an unforeseeable claim amendment. It rather represented a reaction to the negative preliminary opinion on inventive step previously expressed by the Opposition Division. In the impugned decision, the Opposition Division found that this document was prima facie not more relevant than any of the documents D1 to D6 and thus decided not to admit D7 into the proceedings. Since this discretionary decision has been challenged by the appellant, the Board has to decide whether the department of first instance has exercised its discretion properly. It is not the function of the Board to review all the facts and circumstances of the case as if it were in the place of the department of first instance, and to decide whether or not it would have exercised such discretion in the same way as the department of first instance did.

In the present case, the Board has no doubts that the department of first instance has properly exercised its discretion under Article 114(2) EPC. The issue has been addressed by both parties during the oral proceedings held on 28 May 2008 (see points 4 to 7 of the Minutes), and the criterion taken into account by the Opposition Division, viz. prima facie relevance for the outcome of the proceedings, constituted the right and well-established principle in such a situation. Consequently, it cannot be said that the discretion was misused or exercised according to the wrong principles or in an unreasonable way. Accordingly, the Board sees no reason to overrule the Opposition Division's decision not to admit D7.

The Board further observes that D7 does not relate to a recirculation circuit as defined in the claims. It rather describes the measurement of concentration with conductivity sensors (30, 32) within a tank (10) comprising an aperture (50) into which salts are "dumped". The two sensors of D7 are primarily included to determine the point when a homogenous mixture has been obtained rather than the point when complete dissolving of the salts has been reached.

3.3.2 Document D8

D8 was exclusively cited to challenge inventive step of the subject-matter of claim 1 by combining D7 and D8. No line of argument was presented on the basis of D8 alone or starting from D8 as closest prior art, so that the admittance of D8 can only be decided in combination with that of D7. Since D7 was correctly excluded from the proceedings as detailed supra, the appellant's line of argument based on D7 in combination with D8 cannot succeed for this reason alone.

Pursuant to Article 12(1) RPBA the appeal proceedings shall in principle be based on the notice of appeal and the statement of grounds of appeal. D8 was filed with the appellant's statement of grounds of appeal. However, the Board does not accept the appellant's argument that D8 was filed as a "direct reaction" to the Opposition Division's decision. This decision can hardly be seen as surprising given the preliminary opinion previously issued by the Opposition Division. Also, the respondent did not amend the claims during the oral proceedings held on 28 May 2008, and so no change in the subject of the proceedings can be recognised that would cause the filing of new prior art to be a legitimate response to an unforeseeable amendment. In the present case, the filing of document D8 is therefore not justified by procedural reasons and thus late. The Board sees no reason why D8 could not have been cited during the first instance proceedings if it was relevant. Accordingly, D8 represents evidence which could already have been presented in the first instance proceedings and which can be held inadmissible pursuant to Article 12(4) RPBA.

The purpose of the inter partes appeal procedure is mainly to give the losing party an opportunity to challenge the decision against it and to obtain a judicial ruling on whether a first-instance decision is correct (see G 9/91 and G 10/91). The appeal proceedings are thus largely determined by the factual and legal scope of the preceding opposition proceedings. Consequently, the parties have only limited scope to amend the subject of the dispute in second-instance proceedings, and the appeal proceedings are not about bringing an entirely fresh case (see "Case Law of the Boards of Appeal of the EPO", 6th Ed. 2010, VII.E.16.2.1). In the present case, the filing of document D8 at the appeal stage represents an attempt to have the Board consider a different factual framework than the Opposition Division, contrary to the purpose of the appeal procedure.

Finally, the Board does not share the appellant's view that D8 is particularly relevant. D8 is not concerned with the dissolving of a powder but merely relates to the further dilution of a liquid concentrate (9). D8 fails to disclose the monitoring of the concentration in the recirculation circuit and stopping the recirculation when an appropriate concentration is reached. The conductivity sensor (17) is used only after the recirculation has been stopped for checking the concentration of a bolus of liquid to be extracted from the device (see column 5, lines 13 to 24). For this reason, document D8, even if taken alone or in combination with D7, would not have been relevant enough to be admitted into the procedure at this late stage.

Accordingly, the Board exercises its discretion under Article 114(2) EPC in combination with Article 12(4) RPBA not to admit document D8, also in consequence of the fact that D7 is not in the procedure.

3.4 Inventive step

3.4.1 Document D1 as closest prior art discloses a method for preparation of a fluid intended for medical use which method undisputedly comprises features [a] to [e] of claim 1.

3.4.2 From line 66 to 68 of column 7 of Dl it is clear that between the "cycling" step mentioned in the third to the last sentence of the abstract and the "circulation" step mentioned in the next sentence, the valve 82 is closed and the wand 16 empties the drum 12 of all liquid. Then, the wand 16 is disconnected from the flexible conduit 96 and the conduit is instead attached to the coupling 116 of suction pipe 112 (see lines 4 to 7 of column 8 of Dl). Accordingly, the "cycling" mentioned in the abstract is around a different circuit than the "circulation" mentioned in the subsequent sentence. The abstract of Dl neglects to mention the disconnection step since it represents a short summary of the most important steps of Dl. Although the abstract of Dl mentions a cycling step followed by a circulation step, this cannot, and must not, be taken as a teaching in Dl that no disconnection step occurs between the cycling and circulation step. On the contrary, the only disclosure in Dl involves such a disconnection step. Indeed, the disconnection step makes perfect sense given that the first cycling continues "until all of the chemicals in the drum have been removed". It is quite clear that Dl teaches emptying the drum 12 of chemicals in a first circuit and then performing circulation around a different circuit to mix the chemicals.

Feature [f] of claim 1 specifies recirculating water through the mixing vessel after ending supply of the water. Column 7, lines 14 to 17, and column 8, lines 13 to 16 of Dl however disclose that further water is added to the tank 10 after recirculation through drum 12.

Feature [g] of claim 1 states that monitoring takes place in the recirculation circuit. No monitoring at all takes place in the circuit involving drum 12 of D1. Neither does any monitoring take place in the circuit involving tank 10. Dl discloses only checking (once) the conductivity after the fluid has left the tank 10 (see column 8, lines 17 to 22). There is no monitoring in any recirculation circuit. The term "monitoring" implies continuous or repeated measuring. It is clear from lines 17 to 24 of column 8 of Dl that any measuring that takes place in the Dl device is after the filtering step and the filters are referenced 62, 63, 64 in Figure 1. Accordingly, the measuring performed in Dl is done at the very outlet of the device and not in the recirculation circuit.

Feature [h] of claim 1 requires stopping recirculation when the monitored concentration reaches an appropriate value indicating complete dissolving. In Dl, recirculation through the drum 12 is stopped once all the chemicals have been removed from the drum 12, and not at a point of complete dissolution. Lines 53 to 54 of column 8 suggest that this stage is controlled using an automatic timer. Accordingly, it is quite clear that some other method is used for determining when to stop recirculation in the D1 device (such as a timer) and there is no automatic stopping of the recirculation when the monitored concentration reaches an appropriate value. Indeed, it would be impossible for the Dl device to provide this functionality because any conductivity measuring step is carried out only on the final liquid product presented to the "dispense" block of Figure 1 and not in the recirculation circuit itself.

Accordingly, the subject-matter of claim 1 is distinguished over the disclosure of D1 by features [f] to [h].

3.4.3 The technical effect achieved by the above-mentioned distinguishing features is that the claimed method can be used for salts or "powders" of different solubility without calibration, because the decision to stop recirculation is based on the monitored conductivity level, thereby automatically taking account of the possibility of varying lengths of time for complete dissolution of the powder. For the system of Dl, on the other hand, some calibration and programming would be necessary to ensure that the circulation step continues for as long as necessary to dissolve the particular salt. Each time the salt is changed, the system would need re-calibrating.

3.4.4 The objective technical problem to be solved is to provide a method for the preparation of a dialysis fluid or concentrate solution that is more efficient. Although not explicitly stated in the specification of the patent in suit, this problem is derivable from its overall content for the person skilled in the art. The Board does not accept the formulation of the problem proposed by the appellant, namely to further develop the control of D1 such that it can be determined whether the powder has completely dissolved, since this formulation already implies a pointer to the solution, which is not appropriate according to established jurisprudence (cf. "Case Law of the Boards of Appeal of the EPO", 6th Ed. 2010, I.D.4.3.1).

3.4.5 The objective problem is solved by features [g] and [h] because fluid is only recirculated for as long as is necessary to completely dissolve the fluid. No timers are needed which can result in not enough powder dissolving (if the timers are set too short) or wasted time recirculating already dissolved fluid (if the timers are set too long).

3.4.6 It cannot fairly be said that the inventive solution is obvious in view of general technical knowledge. It is, of course, generally known that different salts may have different solubilities, thus requiring different amounts of time to be dissolved. This information alone, however, does not lead the skilled person towards monitoring the concentration and stopping the recirculation if the monitored concentration indicates complete dissolution as defined in features [g] and [h], instead of setting a timer as suggested in D1. It is also not obvious for the skilled person to perform the conductivity measurement in the recirculation circuit instead of checking conductivity after the fluid has left the tank 10 of D1 when trying to avoid that fluid not yet ready for use is removed, as suggested by the appellant. Even if this were the case, it would still be necessary to monitor the concentration/conductivity over time as required in feature [g] and to stop the recirculation as defined in [h] in order to arrive at the invention.

3.4.7 Document D2 does not address the problem of efficiency. Accordingly, there is no reason for the skilled person to consider its teaching when trying to solve the above-mentioned objective problem (point 3.4.4). Figure 7.2.1.1 of D2 shows a spoonful of powder being dumped into a tank, corresponding to the mixing vessel defined in feature [a]. The drawing further shows a "Ringleitung", which could be equated to a recirculation circuit as defined in feature [c], and a conductivity sensor located in a sampling duct leading from the "Ringleitung" to a separate container. D2 merely discloses a one-off conductivity check that is carried out on a batch of withdrawn liquid. Accordingly, D2 does not disclose any monitoring as required by feature [g]. As discussed above, "checking" or "measuring" is not the same as "monitoring". The checking step disclosed in D2 is done on a withdrawn batch of fluid and so it is questionable whether it can be said that it is done in the recirculation circuit, as required by feature [g]. Finally, D2 fails to disclose any link between the checking step and any recirculation. In particular, D2 does not teach any method for determining when to stop a recirculation. Certainly, D2 does not link the checking step with any stopping of a recirculation. D2 is entirely silent regarding feature [h].

Figure 7.2.4 of D2 is even less relevant. It shows a dialyser which would be located downstream of the apparatus shown in Figure 7.2.1.1. In Figure 7.2.4 the fluid bypasses the dialyser if its (monitored) temperature or conductivity/concentration is not correct. This gives a hint towards monitoring the concentration, but under entirely different circumstances and for a different purpose since the fluid is thus wasted and not recirculated.

Accordingly, aside from the fact that D2 does not address the objective technical problem (point 3.4.4) and so would not have been studied by the skilled person, D2 does not teach the solution claimed in the present claims and a combination of Dl and D2 does not result in the invention as claimed.

3.4.8 The Board is satisfied that the subject-matter of claim 1 is based on an inventive step within the meaning of Article 56 EPC. The same applies to claim 9 which corresponds to claim 1 in terms of apparatus features.