T 0545/92 (Gas desulfurization/BABCOCK-HITACHI) 25-01-1994

Reasons for the Decision

1. The appeal is admissible.

2. Extent of examination

Since the only ground given for refusal was infringement of Article 123(2) EPC, the question to be decided in this appeal procedure is whether or not the present claims comply with the provisions of said article, that is whether said claims extend or do not extend beyond the content of the application as originally filed.

3. Article 123(2) requirements of the claims

3.1. Claim 1 of the second subsidiary request

Claim 1 is now restricted to a circulation tank according to the embodiment of Figures 9 and 10 whereas all originally filed claims refer to the - whole - apparatus for wet flue gas desulphurisation comprising a circulation tank (Claims 1 to 18) or a corresponding reservoir (Claim 19).

The decisions T 0331/87, T 0194/84 and T 0066/85 cited by the Appellant deal with amendments where only one feature of a contested claim is omitted or generalised. In view of the considerable differences of the original and amended claims, application of the particular principles of these decisions, above all of the novelty tests and thus comparison of the original claims with the amended claims, to the present case seems to be inappropriate.

Firstly, the question has to be answered whether said tank is disclosed in the original application as being independent of specific features of the whole apparatus for desulphurisation. Secondly, the question remains as to whether all features of Claim 1 can be identified in the original disclosure.

As to the first question, reference is made particularly to page 10, lines 7 to 10 where it is stated that, when the air feeding "means" (of the embodiment of the circulation tank according to Figures 9 and 10) "is employed, slurry agitation and the breaking up and dispersal of fed air are achieved at the same time to make it possible to effect oxidation of calcium sulfite uniformly and with high efficiency". In the Board's view, the skilled person unambiguously comprehends from this sentence that a technical problem resides in the oxidation of said sulphite in the slurry contained in the tank and that this problem is solved by utilising the circulation tank of Figures 9 and 10. It is obvious to him that it is the structure of said tank per se with which the oxidation of a slurry by an oxygen containing gas can be improved and that such an effect is not necessarily dependent on a particular composition of the slurry, let alone a particular structure of the remaining parts of the desulphurisation apparatus. Moreover, there is nothing in the disclosure of the application as originally filed which makes clear that said tank cannot work in the absence of a particular structure of said remaining parts of said apparatus.

As to the second question, reference is made to the description of said tank on page 9, line 31 to page 10, line 22 and to Figures 9 an 10 where all details of the stirring and air-feeding means are disclosed. The features at the beginning of Claim 1 of the three requests characterising the suitability of said tank for its use in said apparatus and the means to feed liquid to and withdrawing slurry from said tank are shown e.g. in Figure 1 and the corresponding description.

Page 9, last paragraph ("In the present invention, as the air-feeding means provided in the circulating tank 36. besides the pipe 30 having a number of perforations as shown in Figure 1, those as shown in Figure 9 or Figure 10 may be also employed ... ") is not quite clear as to whether it means that only both the perforated pipe (30) and the air-feeding means as shown in Figures 9 and 10 are provided in said tank or that these two air-feeding means can be used alternatively, too. However, e.g. original Claim 3 (being dependent on Claim 1) shows that the latter alternative is provided for since in the apparatus defined by Claim 3 pipe means as shown only in Figures 9 and 10 are employed as air-feeding means. A pipe with perforations or the like is not mentioned there.

3.2. Claims 1 of the first subsidiary request and the main request

Claims 1 of the first two requests differ from Claim 1 of the second subsidiary request only in that Claim 1 of the first subsidiary request has no limitation as to the number of lower stirring means and in that Claim 1 of the main request has no limitation as to the number of lower and upper stirring means.

On the one hand, according to page 4, paragraph 8, Figure 10 shows "a cross-sectional view of the arrangement shown in Figure 9". However, none of the air feeding nozzles of Figure 9 (30E, 30F, 30G) is shown in Figure 10 and, vice versa, none of the air-feeding nozzles of Figure 10 (32A-D) is shown in Figure 9. At least one of said nozzles should, however, be drawn in, e.g., nozzle 30D in Figure 9 and nozzle 30G in Figure 10. Moreover, stirrer 32D of Figure 10 is missing in Figure 9. On the other hand the sentence bridging pages 9 and 10 indicates that Figure 9 and 10 show different possible embodiments of stirrer/air nozzle arrangements: " ... as the air-feeding means provided in the circulation tank ... those as shown in Figure 9 or 10. may also be employed ... ". It is the opinion of the Board that the skilled person would unambiguously recognise from the original disclosure that different numbers of upper stirring means and different numbers and arrangements of nozzles in the vicinity of each upper stirring means can be used and that it is up to him to find out an arrangement suitable for the chosen application.

The number of upper stirring means can be also restricted to only one: Though in Figures 9 and 10 two and four stirrers, respectively, are shown and in the description of said Figures on page 9, last paragraph and page 10, paragraphs 1 and 2 four stirrers are mentioned, according to Claims 3, 10 and 14 , however, at least one stirrer with at least one air-feeding pipe is provided in said tank. It should be noted in this connection that stirrers with air-feeding pipes are provided for only in the embodiment of the circulation tank shown in Figures 9 and 10. Moreover, there is no express recitation in the description of the requirement of a plurality of upper stirring means.

Though Figure 10 shows only one lower stirring means (32E) and on page 10, lines 10 to 12, only one lower stirrer is mentioned, there is, however, no express statement in the specification that in said tank only one lower stirring means is present. On page 10, lines 10 to 12 it is stated that the lower stirrer provided below an air-feeding nozzle (30G) of an upper stirrer (32A) prevents the latter from causing an air cavitation. It is clear that when other upper stirrers have a similar nozzle arrangement as said upper stirrer (32A) they could also have a corresponding lower stirrer to prevent also those upper stirrers from causing an air cavitation. Therefore, a restriction of the number of lower stirring means to only one is not justified.

3.3. Dependent claims

The locations of the stirring means of Claims 2 of all requests and the number of upper stirring means of Claim 2 of the main request are shown in Figures 9 and 10.

The features of dependent Claims 3 and 4 (all requests) are disclosed on page 10, lines 17 to 22 of the originally filed description.

3.4. Thus, it is the opinion of the Board that all claims of the three requests meet the requirements of Article 123(2) of the EPC.

4. Thus, the only ground given for refusal (infringement of Article 123(2) EPC) has been overcome by filing new claims.

However, the substantive examination with respect to all the other requirements of the EPC still has to be carried out in respect of the substantially amended claims now on file. Furthermore, due to the significant differences between the wording of the original claims and that of the present amended claims, the Board is unsure whether the search already made (but for example apparently not in International Patent Classification B01F) is still valid for the new claims. Therefore and to avoid loss of an instance with respect to the matters not (fully) dealt with by the first instance, the Board makes use of its power under Article 111(1) EPC to remit the case to the first instance for further prosecution comprising consideration of whether an additional search has to be made and whether the subject-matters of the claims are novel and involve an inventive step.

5. Reimbursement of the appeal fee

In the Grounds of appeal, the Appellant requested reimbursement of the appeal fee, but did not give any grounds for his request.

Apart from the appeal being allowable, a second requirement for reimbursement is that it is equitable by reason of a substantial procedural violation (Rule 67 of the EPC). This latter requirement - e.g. a violation of the provisions of Article 113(1) or (2) or of Article 116(1), first sentence, EPC - is, however, not met.