T 0367/96 03-12-1997

Reasons for the Decision

1. The appeal is admissible.

2. Main request

The appellant requests that the question mentioned in paragraph X here above be referred to the Enlarged Board of Appeal.

This question has two main aspects, i.e. a first aspect about the "interest to make opposition", and a second aspect relating to "futility" of an invention, that is, the lack of any useful result by implementing said invention.

Concerning the first aspect, it is to be noted that, as mentioned by the Board during the oral proceedings, there is no indication derivable from the European Patent Convention that an "interest to make opposition" is required and, moreover, this finding has been stressed in decisions of Boards of appeal. This is for instance clearly mentioned in the decision T 798/93, OJ EPO, 1997, 363 (cf. point 3.2.1 of the reasons).

Concerning the second aspect, i.e. the "futility" of an invention, it is first to be noted that, whatever the arguments the opponent used in the present case in the course of the opposition and following appeal procedures, the grounds of opposition contained in the notice of opposition were however lack of novelty (Article 54 EPC) and lack of inventive step (Article 56 EPC), i.e. grounds according to Article 100(a) EPC, so that, in this respect, the opposition was admissible (Rule 55(c) EPC).

It is also to be noted that in the first decision T 1027/93 (cf. point 4 of the reasons) of a Board of appeal on the basis of the present European patent, it was stated that, for a construed case comprising a feed gas with two gases A and B, "whether the aim is partial or complete removal of B, the apparent futility of achieving this by carrying out the claimed process cannot be said to be obvious; in fact in view of the futility, it could be said to be completely non-obvious". In said first decision, the Board considered in particular that the question of novelty with respect to D1 required further prosecution because of a questionable interpretation of a term of the claim and that lack of inventive step could not be convincingly based only on the finding that the solution of a problem to be solved was "futile". Moreover, the present Board had expressed in the annex to the summons to oral proceedings that, taking into account the above-mentioned decisions T 939/92, (cf. point 2.4.2 and also point 2.7 of the reasons) and T 222/89 (cf. points 2 and 4.8, and also points 3, 5 and 6 of the reasons), even in case that a contribution to the technique was not apparent or that no problem seemed to be solved, examination of novelty and inventive step appeared in any case to be necessary. Accordingly, it was mentioned that, in the present case, the method of claim 1 as granted seemed to lack an inventive step.

The reasons given by the appellant (proprietor) for this late submission, one week before the oral proceedings, concerned more a general interest for this question, which in its opinion should be settled, than a need concerning the present case, and they were thus not convincing for the finding of the present decision. Moreover, concerning the combination of both aspects, i.e. the futility and the interest to act, the respondent has argued that the present invention was indeed "futile", but has stressed convincingly that, in any case, an opponent could nevertheless have an interest to oppose for avoiding possible future infringement suits on the basis of a granted patent covering a large field.

Therefore, since this submission has been filed less than one month before the date of the oral proceedings and thus has not been submitted in due time and since "prima facie" it is relevant neither for the present decision nor in general because in any case, whatever the nature of the arguments, the opposition must be based on the grounds of opposition listed in the Convention, the question needs not be referred to the Enlarged Board of Appeal and, thus, said submission is disregarded in accordance with respondent's request (Articles 112(1)(a) and 114(2) EPC).

3. First auxiliary request (patent as granted)

3.1. It has not been disputed that D1 represents the nearest prior art. The method known from D1 (see column 1, line 5 to column 2, line 32; column 3, lines 9 to 60; Figure 1) is for continuous substantial separation of at least one gas component (H2) from a gas mixture (H2, 62%; N2, 21%; Ar, 6%; CH4, 11%; pressure of the gas mixture 125 bar) fed by the conduit (6) to generate in conduit (10) a residue gas substantially depleted of said gas component (15% H2); this method comprises the steps of:

providing a semipermeable membrane (9) having a feed gas side in communication with the incoming conduit (6) and the outgoing conduit (10) and a sweep gas side in communication with the conduits (11) and (12);

contacting said feed gas side of said semipermeable membrane (9) with a feed gas mixture in conduit (6) containing at least one gas (N2, 21%; Ar, 6%; CH4) to be retained and at least one gas (H2) to be separated therefrom;

simultaneously contacting said sweep side of said semipermeable membrane with a sweep gas (N2) provided by conduit (11) having a pressure (about 25 bar) lower than that of said feed gas (125 bar);

withdrawing by conduit (10) a residue gas after contact with said feed side of said membrane (9) which is substantially depleted of said gases (H2) to be separated;

withdrawing a permeate gas (H2) after contact with said sweep side of said membrane which is substantially enriched with said gases (H2) to be separated.

Taking into consideration the partial pressures of one of the gas components (N2) to be retained on said feed gas side which is present on both sides of the membrane (9), and using the same calculation principle as in the patent in suit (see for instance column 7, lines 4 to 26), the partial pressures in D1 are the following:

feed side: with a pressure of the gas mixture about 125 bar, the partial pressure of a gas component to be retained, N2, i.e. of 21% of said gas mixture, is "about 125" x 0.21 = about 26.25 bar.

Thus, since for N2 the difference "about 26.25 bar" - "about 25 bar" = "about 1.25 bar", it cannot be concluded directly and unambiguously that the method of D1 further comprises

"balancing the partial pressure of one of the gas components to be retained on said feed gas side which is present on both sides of the membrane so that the partial pressure differential on both sides of the membrane is substantially zero."

The further documents of the cited prior art are less relevant.

Therefore, the subject-matter of claim 1 as granted is new in the sense of Article 54 EPC.

3.2. According to the patent in suit (see column 2, lines 30 to 42), balancing of the partial pressures of a component of the gas mixture on both sides of the semipermeable membrane causes the minimal passage of the gases to be retained, in particular of the gas with balanced partial pressures, in either direction across the membrane and maximizes the passage of the gas to be separated from the feed gas side to the sweep gas side.

However, starting from the above - mentioned example of the method known from D1 wherein the difference of partial pressures of the gas component N2 of the feed mixture to be retained is "about 1.25 bar" as compared with partial pressures of said same gas component on both sides of the semipermeable membrane to be retained of "about 26.25 bar" and "about 25 bar", i.e. a ratio of about 0.05, the person skilled in the relevant art intending to carry out said example and making simple trials for adjusting the process parameters (about "125 bar", "about 26.25 bar" and "about 25 bar") will arrive inevitably to values of the differential partial pressures of said gas components which are very near to "substantially zero".

It is to be noted in this respect that the process of this example of D1 is for separating and recovering H2 from a feed gas comprising also i.a. N2. The amount of N2 is controlled so that the thus formed mixture withdrawn via conduit (12) from the feed side of the membrane device has a H2 proportion of about 75% molar; with such a composition, the gaseous mixture can be directly returned after some compressing into an ammonia synthesis system, from which the off-gases had been treated and directed to the feed gas side of the membrane.

Thus, the person skilled in the art of D1 receives from this document the teaching that, in order to adjust the separation capability of a semipermeable membrane for a specific component (H2) of a feed mixture having at least two components (H2 and N2 ), it is necessary to provide directly a gas of the component (N2) to be retained on the other, sweep side of the membrane with an amount, i.e. with a partial pressure, resulting in the desired amount or proportion of H2. Since D1 (see column 1, lines 52 to 54) is not restricted to the implementation of the separation system with an ammonia synthesis system, the person skilled in the art will control the amounts of gas components and arrive, if this is necessary for another implementation of the separation system, in an obvious way at a differential pressure which does not differ from substantially zero, so that the subject-matter of claim 1 as granted lacks an inventive step in the sense of Article 56 EPC.

4. Second auxiliary request

The method of the second auxiliary request is for continuous substantial separation of at least one gas component from a feed gas mixture to generate a residue gas substantially depleted of said gas components. From one of the amendments resulting in this request, said gas mixture is mentioned as containing two gases to be retained, which gases are present on said sweep gas side of the membrane. The claim goes further saying that there is a step of contacting said feed gas side of said semipermeable membrane with a feed gas mixture containing at least one gas to be retained and at least one gas to be separated therefrom. Then, the claim goes farther stating, according to a provided amendment, that there is a step of 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 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.

Leaving aside deficiencies of the text of the claim, whereby for instance the "sweep gas side" is mentioned before being defined, there is thus a first ambiguity relating to the number of gases to be retained which is introduced by the amendments. There is also a second ambiguity relating to which of said gases to be retained is submitted to a balancing with a partial pressures which are substantially equal across the membrane, and to which other of said gases to be retained is submitted to the second partial pressure differential, which is only less than the partial pressure differential of the gas to be separated and such that the desired effect, in particular the "minimizing" of the diffusion of said gas component to be retained, is obtained.

Therefore, because of these ambiguities introduced by the amendments, claim 1 of the second auxiliary request "prima facie" lacks clarity in the sense of Article 84 EPC and cannot serve as a basis for maintaining the patent in amended form since said patent does not satisfy the requirements of the Convention (Article 102(3) EPC). For this reason, the second auxiliary request, which has not been submitted in due time, is disregarded in accordance with respondent's request (Article 114(2) EPC).

5. Third auxiliary request

Claim 1 of the third auxiliary request results in substance from the combination of claim 1 and dependent claim 6, both as granted, and concerns thus a fermentation process wherein the off-gases is comprised of a gas mixture which is utilized as a feed gas mixture in the separation process. However, this means that the method of claim 1 of the third auxiliary request differs in substance from the method of claim 1 of the first auxiliary request, i.e. as granted, only in that the former specifies that the method is applied to off-gases of a fermentation process, all other features remaining the same. Thus, the method is for retaining only "at least one gas". Since the method of D1 can be applied to any method wherein it may be desirable to separate at least one gas component and thus to the treatment of fermentation off-gases, the method of the third auxiliary request "prima facie" lacks an inventive step for the same reasons as those put forward here above in relation with the first auxiliary request, so that this request, which has not been submitted in due time, is disregarded in accordance with respondent's request (Article 114(2) EPC).

6. Fourth auxiliary request

6.1. Claim 1 of the fourth auxiliary request results in substance from the combination of claim 1 and dependent claims 2 and 6, all as granted, and concerns thus a fermentation process wherein the off-gases is comprised of a gas mixture comprising at least one gas to be separated and two gases to be retained. It is first to be noted that already in the first decision of the Opposition Division a combination of this type had been mentioned as possibly involving an inventive step so that, although this request has not been filed in due time, the Board nevertheless decides to admit it in the procedure (Article 114(2) EPC).

There has been no objection of the respondent concerning the amendments having led to this request, and the Board can see no objection either in this respect (Article 123(3) and (2) EPC). The wording of claim 1 of this request makes it clear to the skilled person, if necessary with his general expertise and if further needed by taking into account the content of the description of the patent in suit (see column 2, lines 20 to 47), what process is meant; in particular, the process can comprise passing air enriched with oxygen through a fermentation vat for speeding up the fermentation reaction, this air/oxygen enrichment producing off-gases from the fermentation vat consisting for example of 30% by volume of oxygen, 55% by volume of nitrogen, and 15% by volume of carbon dioxide, which are returned to the separation system to maximize the passage of carbon dioxide from the feed gas side of the membrane to the sweep gas side thereof and thus recycling of a mixture comprising mainly nitrogen and oxygen.

6.2. The respondent has objected that in the description and drawings of the patent in suit there was no example, and in particular no numerical example, of carrying out the invention in accordance with the features of claim 1 of the fourth auxiliary request, so that there was lack of support by the description in the sense of Article 84 EPC. This argument could not convince for the following reasons:

Without going into numerical calculation for checking whether actually there is a discrepancy between claim 1 of this request and the description, it is to be noted first that said claim 1 results in substance from a combination of claims 1, 2 and 6 as granted in accordance with the cross references stated therein and that, thus, this combination concerns a specific process which as such was already claimed in the patent as granted. If there is lack of support in the sense of Article 84 EPC in the patent maintained in amended form on the basis of the fourth auxiliary request, said lack of support was already there in the patent as granted and has not been introduced after grant of the patent, so that, following for instance decision T 301/87, OJ 1990, 335 (cf. points 3.7 and 3.8 of the reasons), it is concluded that Article 102(3) EPC does not allow objections to be based upon Article 84 EPC if such objections do not arise out of the amendments made.

The terms such as "balancing", "maximizing" or "minimizing" which are objected by the respondent with respect to their ambiguity were also there in the claims of the patent as granted, so that, for the same reason, respondent's objection of lack of clarity is not relevant either.

6.3. Concerning the sufficiency of disclosure, it is to be noted that, although for the reasons mentioned here above contradictions between the claims and the description concerning the values of the parameters may result in difficulties for the skilled person, however, there is in the opinion of the Board sufficient information in the patent in suit for him to be able to control the partial pressures of each of the three gases of the feed mixture which comprises the off-gases of a fermentation process and which thus are enough defined, so that he will be able to carry out the process to arrive at the intended result, i.e. the intended separation.

6.4. The process of claim 1 of the fourth auxiliary request is neither known from nor obvious having regard to D1 (see in particular Figure 1 and the corresponding text), which does not show a fermentation process or a process wherein the two same gases are flown on the feed side and the sweep side of the membrane for separating a third gas initially in the feed stream. The further prior art documents showing membranes are less relevant and, starting from D1, do not render obvious the subject-matter of the fourth auxiliary request. Therefore, the subject-matter of claim 1 of the fourth auxiliary request is novel in the sense of Article 54 EPC and involves an inventive step in the sense of Article 56 EPC. The same conclusion applies to Claim 5, which is concerned with an apparatus for carrying out methods of this type, so that the claims are allowable in the sense of Article 52(1) EPC and the patent can be maintained on this basis (Article 102(3) EPC).