T 1186/20 06-10-2023

1. Main request (patent as granted) - patentability

The opponent raised the following objections of lack of patentability of the subject-matter of claim 1 of the main request:

- the subject-matter was not novel in view of the disclosure of D3

- the subject-matter did not involve an inventive step in view of, inter alia, D3 as the starting point in combination with the teaching of D5.

The patent proprietor requested that the novelty objection based on D3 not be admitted.

1.1 Consideration of the novelty objection based on D3

The opposition was solely based on the ground for opposition under Article 100(a) EPC in conjunction with Articles 52(1) and 56 EPC. The novelty objection based on D3 thus constitutes a fresh ground for opposition (Article 100(a) in conjunction with Article 54 EPC, see G 7/95, headnote, first sentence).

The novelty objection was raised for the first time with the statement setting out the grounds of appeal as an "auxiliary approach" relying on a specific - and compared to the opposition proceedings different - understanding of the feature [1.5] ("an air trap for preventing the steam from reaching the outer environment through the inlet itself").

However, the allegation that the subject-matter of claim 1 lacks novelty over D3 is considered for the following reasons.

1.1.1 D3 had already been relied on in the notice of opposition as the starting point for an objection of lack of inventive step, an objection which was re-submitted in the statement setting out the grounds of appeal. Construing the features and then establishing the distinguishing features with respect to the closest prior art D3 is a precondition for the assessment of inventive step.

Following G 7/95, headnote, second sentence, the Board thus decided to consider the allegation that the claims lacked novelty over D3 in the context of deciding upon the ground of lack of inventive step.

1.1.2 D3 discloses a feeding unit shown in Figures 4 to 6 which includes a tank, a water inlet ("Einlass zum Befüllen mit einer Flüssigkeit 26.1.1") and a steam generator ("Durchlauferhitzer 26.2") in fluid communication with the tank. It was under dispute whether features [1.3], [1.3.1], [1.3.2], [1.5] and [1.5.1] were disclosed in D3.

1.1.3 Features [1.5] and [1.5.1]

The opponent's novelty objection was based inter alia on the understanding that the whole tank had the function of an air trap and this tank structure thereby anticipated features [1.5] and [1.5.1].

This interpretation is not persuasive. As already concluded by the opposition division in the appealed decision, the skilled person understands the term "air trap" in feature [1.5] as a distinct technical feature and not merely as a function of the overall tank structure as such.

An air trap is a technical term with a distinct meaning and encompasses a "U-" or "S"-shaped pipe section to prevent gases (here vapour) from escaping a liquid body. This structure is commonly known to a skilled person (e.g. "drain traps"). Such an air trap is shown in the patent (reference 20), but also e.g. in D5, Figure 4 (reference 31).

Since D3 does not disclose such an air trap, features [1.5] and [1.5.1] are features distinguishing the subject-matter of claim 1 from D3.

1.1.4 Features [1.3], [1.3.1] and [1.3.2]

Features [1.3], [1.3.1] and [1.3.2] are product-by process features ("two shells permanently connected to each other along a junction line"), the result of which is an integral single-piece tank. It was not in dispute that the final tank product manufactured in accordance with features [1.3] to [1.3.2] is distinguishable from single-piece tanks produced by other methods.

Tank 26.1 is shown in the figures of D3 as an integral single part together with the sleeves. This is also confirmed by the hatching in the cross-sectional view of Figure 5: tank and sleeves all have the same hatching here.

D3 gives no indication of a method for producing this single piece integral tank. Paragraph [0026], lines 43-45, merely states that the tank and sleeves are formed as a single plastic part (emphasis added: "Der Tank 26.1 ist als ein Kunststoffteil ausgebildet und weist einen Einlass 26.1.1 und einen Auslass 26.1.2 auf ["The tank 26.1 takes the form of a plastics part and has an inlet 26.1.1 and an outlet 26.1.2"]).

The opponent's view that a manufacturing method involving joining two half-shells is implicit for a tank as in D3 is not persuasive.

Firstly, the opponent did not state that it was impossible to manufacture a tank as in D3 as a single piece in a single step. They only argued that in view of the geometry of the tank it was highly unusual and technically very challenging to produce the tank directly as a single piece with known processes ("Schleuderguss" ["centrifugal casting"]). A manufacturing method producing two half-shells which are subsequently joined was thus highly preferable and obvious to the skilled person. This argument, however, is not relevant for the assessment of a direct and unambiguous disclosure, i.e. a question of novelty, but may be relevant only in the assessment of obviousness.

Secondly, the Board sees no evidence in support of an implicit disclosure in D3. The thicker lines emphasized by the opponents at the half diameter of the tank 26 displayed in Figures 3 and 6 of D3 and alleged pre-mounting clips in Figure 4 identified by the opponent cannot support the opponent's view. D3 is mute regarding these allegedly thickened lines and also does not describe any pre-mounting clips. For example, the lines could also indicate reinforcements integrally formed with the tanks side walls.

Therefore, D3 does not - even implicitly - exclude manufacturing methods involving forming the tank in a single step (or other manufacturing methods) provided a final integral tank is obtained. Features [1.3] to [1.3.2] are thus not directly and unambiguously disclosed in D3.

1.1.5 To conclude, the Board considers that claim 1 of the main request is novel over D3 which does not disclose features [1.3] to [1.3.2], [1.5] and [1.5.1].

1.2 Inventive step - D3 as the starting point in combination with D5

Of all the documents which the opponent considered as closest prior art (E1, E2 - figures 3 and 4, D3 and D9), only D3 discloses construction details of the tank shell (see Figures 4 to 6). In addition, D3, like the patent, addresses the problem of reducing the number of parts by integrating functional features with the shell parts (see e.g. paragraph [0015]). The Board thus considers D3 to be the most promising starting point for the discussion of inventive step.

The distinguishing features are [1.3] to [1.3.2], [1.5] and [1.5.1] as considered above (see point 1.1.5).

The Board has concluded that the subject-matter of claim 1 of the main request does not involve an inventive step as explained in the following paragraphs.

1.3 Objective technical problems

1.3.1 Contrary to the patent proprietor's view, the Board is not convinced that all the distinguishing features relate to the objective technical problem of producing the tank in a relatively low-cost manner.

Firstly, it is not convincing that the provision of an additional structural element (the air trap) can be related to the problem of lowering costs.

Secondly, there is no structural or functional relationship between the provision of an air trap as such and the question of how this air trap is integrated into the tank in the manufacturing process thereof.

1.3.2 Instead, the distinguishing features have to be grouped and relate to the following different (partial) technical problems.

Features [1.3] to [1.3.2] and [1.5.1] all are product-by-process features of the tank and its integral features obtained by joining two shells. It is acknowledged for this feature group that the partial technical problem 1 is to produce the tank in a cost-efficient manner (see patent, paragraph [0012]).

However, the provision of an air trap as such in accordance with feature [1.5] addresses another technical problem (partial technical problem 2) which is to prevent steam from (exiting the tank) and flowing along the (inlet) duct and from leaving the oven (see patent, paragraph [0039]).

1.3.3 The patent proprietor's argument that the partial technical problem 2 "to prevent steam from flowing along the [inlet] duct and from leaving the oven" was not allowable since it already encompassed parts of the solution is not persuasive.

While, as argued by the patent proprietor with reference to various cases, it is established case law that, as a rule, the technical problem should not contain a pointer to the solution, in the case at hand the Board has concluded that the formulation of partial technical problem 2 does not in fact point to the solution. Contrary to the patent proprietor's view, this problem relates solely to the technical effect that the distinguishing features have, and does not anticipate the specific solution of the provision of an air trap at the inlet as defined in feature [1.5] (see construction of the feature "air trap" under point 1.1.3 above).

Providing an air trap is also not the only way to solve the problem of preventing steam from leaving the tank (i.e. it is not a "one-way" solution). By way of example, the patent proprietor itself pointed to the possibility of closing the inlet line with a valve as an alternative means (such as valve 44 in D3) for addressing and solving the problem. The patent proprietor also did not present any other convincing technical problem which could be related to feature [1.5].

1.3.4 In the appealed decision, the opposition division additionally concluded that the inclusion of an air trap to the water inlet of the tank in D3 was not obvious to the skilled person since for the embodiment shown there was no risk of steam escaping the oven via the inlet line (i.e. partial problem 2 did not even arise). This conclusion was based inter alia on the argument that in steaming operation, the water in the tank would not fall below the level at which the steam would come into contact with the water inlet.

The Board is not convinced by this line of reasoning either.

Firstly, in D3 - as in the patent - forced circulation is established in the tank during steam generation. Due to imperfect separation of steam and water, this includes the risk of steam distribution within the whole tank, including also in the inlet section, even if this is initially completely filled with water.

Secondly, an air trap is also considered necessary in the patent, although the tank has a lower narrow middle section and further includes baffles (45) between the water inlet and the steam generator.

Contrary to the patent proprietor's view, the Board also sees no reason why the tank of D3 would not be suitable for the integration of an air trap at the inlet sleeve in view of the similar design of the tank and the position of the inlet sleeve compared to the embodiment of the patent.

1.4 The skilled person would consider the teaching of D5

The patent proprietor argued that direct manufacture of a single piece would be the straight-forward solution starting from D3 and therefore there was no need to consider the teaching of D5. Moreover, the tank in Figure 4 of D3 was not suited to being produced from two shells.

These arguments are not convincing.

As explained above, D3 does not reveal any details about the manufacturing method. For more complex tank structures - even if the connectors are formed at the connection line - a direct single-piece molding process might well be more expensive than the two-shell manufacturing method. The skilled person is thus not prevented by any technical prejudice from considering the teaching of D5.

Like D3, D5 also discloses a feeding unit with a tank and a steam generator for a household appliance.

The Board agrees with the conclusion in the appealed decision that the skilled person starting from a steam oven in D3 would - in view of technical problems 1 and 2 - consider the teaching of D5, despite the steam feeding unit disclosed herein stemming from a different household appliance than the patent (laundry machine).

The fact that D5 concerns a different household appliance does not, in the present case, prevent the skilled person from considering this teaching. Water tanks for steam generators for the appliances of D3 (oven) and D5 (laundry machine) are comparable in terms of their design constraints. In addition, the manufacturing method of the tank does not seem to be related to the type of household appliance requiring steam.

1.5 Partial problem 2 - obviousness of the air trap

1.5.1 The patent proprietor argued that the skilled person would not consider the teaching of D5 since a solution to the problem was already provided in D3. The oven disclosed in D3 already had means suitable for preventing steam from leaving the oven. In particular, it encompassed a valve 44 and a pump 22 in the feeding duct to shut off the tank from the inlet duct. According to D3, paragraph [0016] the valve was closed in the cleaning mode and during normal operation. For this reason, a skilled person could possibly consider an alternative solution as in D5, but would see no incentive to do so.

However, the Board is not convinced that the skilled person would consider the valve and the pump as a solution to technical problem 2. The valve is only described as liquid-tight ("flüssigkeitsdicht") and not as steam-tight. Furthermore, the valve is disclosed in D3 for a different purpose, namely to reduce noise emissions from the oven.

Moreover, the air trap according to feature [5.1] prevents steam from exiting the tank as such. This corresponds to the statement in paragraph [0039] of the patent according to which steam should be prevented from "flowing along the filling duct and [subsequently] from leaving the oven through the wall". In D3, between the inlet to the tank and the valve, there is in fact such a filling duct (24) which would still come into contact with the steam up to the valve even if the valve were closed.

Therefore, the skilled person would not consider the valve and the pump in D3 as a means of solving the objective technical problem but would consult further prior art such as D5.

1.5.2 D5 discloses an air trap ("siphon 31") connected to the inlet of the water inlet sleeve (see Figure 4, "water inlet 22a"). This air trap is described to have the same purpose of preventing steam from entering the water inlet duct (see paragraph [0010]) as according to the objective technical problem. The skilled person would, therefore, also consider adding such a valve to the inlet sleeve of the tank in D3.

To conclude, feature [5.1] is obvious in view of the disclosure of D5.

1.6 Partial problem 1 - obviousness of the product-by-process features

1.6.1 As disclosed in Figure 5 of D3, forming a tank with integral functional features from two shells connected along the periphery is a commonly known manufacturing method and can be considered as part of common general knowledge. This is exemplified by the numerous disclosures referred to by the opponent:

- D1: page 5, lines 27-29

- D4: Figure 2 and column 4, lines 4-8

- D5: Figure 4 and paragraph [0012]

- D6: Figure 4 and claim 6

- D7: Figure 10 and page 8, line 35 to page 9, line 1

- D8: page 1, lines 12-23

It is therefore not persuasive that the skilled person would generally prefer a single-piece manufacturing method or that the two-shell design gives rise to concerns about the tightness of the connection.

1.6.2 D5, in particular, discloses that the tank can be effectively produced by injection moulding of two plastic half-sleeves, which are subsequently joined together (paragraph [0012]), e.g. by welding or gluing. D3 does not disclose any method for manufacturing the integral tank. Therefore, in looking for a suitable method, the skilled person would consider this teaching of D5 as being part of the common general knowledge of the skilled person and would apply it even without a particular pointer to do so.

In addition, D5 also discloses that the air trap is formed integrally with the tank to simplify manufacture (see paragraph [0011]). Forming functional parts integrally with the tank is already considered to have been disclosed by D3 (see paragraph [0013]), for another part, i.e. a demister ("Tropfenabscheider 26.1.4"), such that there are no obstacles to implementing an integrally formed air trap within the context of a two half-sleeve tank design.

1.7 To conclude, the solution to partial problems 1 and 2 according to claim 1 of the main request is obvious in light of the disclosure of D5 and common general knowledge. Therefore, the subject-matter of claim 1 including features [1.3], [1.3.1], [1.3.2] and [1.5.1] does not involve an inventive step.

2. Auxiliary requests A1 to A3 - admittance

The opponent requested that auxiliary requests A1 to A3 not be admitted since they were filed late in the appeal proceedings.

Auxiliary requests A1 to A3 correspond to auxiliary requests 2, 3 and 5 at the time of the oral proceedings before the opposition division and were all subject to the appealed decision. These requests were re-submitted during the appeal proceedings with the reply to the opponent's appeal.

They are thus not an amendment in the sense of Article 12(4) RPBA 2020 but part of the appeal case according to Article 12(2) RPBA 2020. The Board has thus no discretion not to admit auxiliary requests A1 to A3.

3. Auxiliary request A1 - inventive step

Compared to claim 1 of the main request, claim 1 of auxiliary request A1 includes additional features [1.4a] (coupling sleeve), [1.5a] (manufactured as one single piece together with said shells) and [1.5.2] (air trap obtained at the inlet of the sleeve).

None of the added features [1.4a], [1.5a] and [1.5.2] establishes a further distinguishing feature over the disclosure of D3 as compared with the main request.

D3 also discloses sleeves - inter alia an inlet sleeve (26.1.1.) - manufactured with the tank shell as a single piece.

The location of the air trap at the inlet of the sleeve is already an implicit requirement of functional feature [1.5] (to prevent the steam from reaching the outer environment of the tank). In addition, it is also disclosed in D5.

Therefore, the conclusions with respect to the inventive step of the main request for the combination of documents D3 and D5 also apply mutatis mutandis to auxiliary request A1.

4. Auxiliary requests A2 and A6 - Article 123(2) EPC

The wording ("obtained at the outlet of the sleeve") according to feature [1.5.2'] of auxiliary requests A2 and A6 has no basis, whether explicit or implicit, in the application as filed.

Therefore, claim 1 of auxiliary requests A2 and A6 are not allowable under Article 123(2) EPC.

5. Auxiliary request A3 - inventive step

Claim 1 of auxiliary request A3 adds - compared with auxiliary request 1 - only feature [1.5.1.1] ("air trap manufactured partly on the first shell and partly on the second shell"). But even on consideration of this additional feature [1.5.1.1], the subject-matter of claim 1 does not involve an inventive step in view of the combination of D3 and D5 and common general knowledge (cf. also point 3. above).

The two-shell design disclosed in D5 already encompasses an air trap manufactured partly on both shells. This is shown in Figure 4, where the first shell with an open channel structure of the air trap (31) is closed by the second shell not shown in Figure 4 (cf. also paragraphs [0011] and [0012]).

Therefore, as was also concluded in the appealed decision, once the skilled person has considered the two-shell manufacturing method as disclosed in D5 (see point 1.6.2 above), this also points them towards the formation of the air trap in accordance with feature [1.5.1.1].

6. Auxiliary request A4 - inventive step

The subject-matter of claim 1 of auxiliary request 4 does not involve an inventive step.

The only further limiting feature [1.5.3] of claim 1 of auxiliary request A4 compared to the main request defines a separation chamber manufactured as a single piece with the shells of the tank.

The tank in D3 also includes a separation chamber as an integral part of the tank shell (see D3, paragraphs [0013], [0036] and Figure 5: "Tropfenabscheider 26.1.4" ["demister 26.1.4"]). The distinguishing features over D3 are the same as for the main request.

Therefore, the conclusions with respect to the inventive step of the main request for the combination of documents D3 and D5 also apply mutatis mutandis for auxiliary request A4.

7. Auxiliary request A5 - inventive step

7.1 The further restrictions in form of features [1.3.3] and [1.5.2] added to claim 1 of auxiliary request A5 do not - compared to auxiliary request A4 - result in any further distinguishing feature over D3.

Feature [1.3.3] corresponds in substance to the combination of features [1.4a] and [1.5a] of auxiliary request 1. As already concluded above for claim 1 of auxiliary request 1 (see point 3.), these features are also disclosed by D3.

The tank disclosed in D3 also comprises inlet and outlet sleeves integral to the tank shell (see Figure 5, sleeves 26.1.1 and 26.1.2 as well as the connectors to the steam generator).

Therefore, the conclusions with respect to auxiliary request 1 for the combination of documents D3 and D5 also apply mutatis mutandis to auxiliary request A5.

8. Auxiliary request A7 - admittance

The opponent requested that auxiliary request 7 not be admitted.

Auxiliary request A7 was submitted for the first time with the reply to the opponent's appeal in the opposition appeal proceedings. Auxiliary request A7 is thus an amendment under Article 12(4) RPBA 2020 and the Board has discretion with respect to its admittance.

Additionally, under Article 12(6), second sentence, RPBA 2020, the Board shall not admit requests which should have been submitted in the proceedings leading to the decision under appeal, unless the circumstances of the appeal case justify their admittance.

Compared to auxiliary request A8, which was filed during the opposition proceedings (as auxiliary request 6), the only difference is that feature [1.3.3] (coupling sleeves integral to the shells) has been omitted in claim 1.

It is not apparent what circumstances could have led to the submission of an additional request with this amendment. The patent proprietor argued that the omission of feature [1.3.3] was in response to an earlier clarity objection. This is not convincing since none of the claim requests on which the decision under appeal is based comprises feature [1.3.3].

Therefore, the Board decided not to admit auxiliary request A7 into the appeal proceedings.

9. Auxiliary request A8

Claim 1 of auxiliary request A8 includes, compared with auxiliary request 5, further features [1.6] and [1.7] which define a discharge for the tank and a filter for filtering this discharge.

The opponent raised objections against claim 1 of auxiliary request A8 under Articles 123(2), 84 and 56 EPC.

However, auxiliary request 8 is allowable as explained in the following paragraphs.

9.1 Auxiliary request A8 - Article 84 and 123(2) EPC

Claim 1 of auxiliary request A8 is based on a combination of the features of original claims 1, 6, 7, 8, 13 and 15 with the addition of feature [1.5.2].

9.1.1 The opponent raised the following objections under Article 123(2) EPC.

(a) Feature [1.5.2] further included embodiments not originally disclosed, i.e. the air trap being arranged outside the tank upstream of the sleeve.

(b) Feature [1.5.2] was originally disclosed only in paragraph [0022] together with the feature that the air trap was manufactured partly on both shells and was obtained at the inlet of the sleeve, i.e. above the sleeve. The omission of the latter features constituted an non-allowable intermediate generalisation.

The opponent additionally argued that the inclusion of feature [1.5.2] gave rise to clarity issues.

These objections are not convincing as explained in the following paragraphs.

9.1.2 As to a) - air trap outside the tank

The opposition division's conclusion in the appealed decision, according to which the claim wording encompassed feeding units with the air trap located outside the tank, is not persuasive.

Features [1.3.3], [1.4], [1.5], [1.5.1] and [1.5.2] have to be interpreted in combination and not in isolation, contrary to the approach in the appealed decision ("when regarded in isolation"). These features which all stem from the original claims already define an inlet with a coupling sleeve and an air trap functionally linked to this inlet.

The interpretation that the air trap is arranged outside the tank (i.e. interpreting the term "inlet" according to a possible direction of water flowing into the tank) is excluded by the wording of claim 1 since the coupling sleeve is defined for connecting the tank to a feeding duct and not to an air trap (feature [1.3.3]). Furthermore, feature [1.5] requires that the air trap be suitable for preventing the steam from reaching the outer environment through the inlet, i.e. with respect to the direction of vapour flow, the sleeve is upstream of the air trap.

Therefore, claim 1 encompasses solely an air trap located relative to the sleeve inside the tank as also originally disclosed.

9.1.3 As to b) - omission of "partly on both shells"

The opponent argued that feature [1.5.2] stems from the description of the application as filed (see paragraph [0022] of the A-publication) and was only disclosed together with the feature that the air trap was manufactured partly on both shells. The omission of the latter constituted an non-allowable intermediate generalisation.

This is not persuasive. For the reasons given above, the combination of features [1.3.3], [1.4] and [1.5] already implicitly defines what is then explicitly confirmed by feature [1.5.2]. Therefore, feature [1.5.2] is also (implicitly) disclosed in original claims 1, 7 and 8.

It is thus of no relevance for the question of added matter that feature [1.5.2] relies on the same wording used in the description of the embodiment in paragraph [0022].

9.1.4 Feature [1.5.2] (obtained at the inlet of the sleeve) is also clear. For the device as such the term "inlet" is not a functional restriction for the flow direction in service. By way of illustration: the sleeve could e.g. be considered to have two inlets, one from each side. Due to the further restrictions, the location of the air trap relative to the sleeve is unambiguously defined.

9.2 New objection under Article 123(2) EPC - admittance

For the first time during the oral proceedings before the Board, the opponent raised the following additional objection under Article 123(2) EPC.

The opponent argued that claim 15 could not be considered as a basis for the amendments. Claim 15 of the application as filed was not dependent on any of the previous claims, in particular not on claim 13, but only on itself and a non-existent claim "16". The obviously incorrect back-references in claim 15 were later corrected under Rule 139 EPC (see patent as granted, claims 12 to 14).

These new arguments constitute an amendment of the opponent's appeal case under Article 13(2) RPBA 2020. The opponent also did not invoke special circumstances as would be required and the Board could not identify any either.

Furthermore, a decision against the patent proprietor who had been duly summoned but who failed to appear at oral proceedings before the Board may not be based on these new facts put forward by the opponent for the first time during those oral proceedings (cf. G 4/92, headnote, first sentence).

Therefore, the Board exercised its discretion and decided not to admit the new arguments.

9.3 Auxiliary request A8 - Inventive step

Claim 1 of auxiliary request A8 includes inter alia features [1.6] and [1.7] which define a filter device provided in a fluid line with a first port connected to the tank and a second port connected to the steam generator. The filter further comprises a discharge and the filter filters "the water fed to the discharge itself", i.e. the filter only filters water entering the discharge "to prevent the limescale present in the water to reach the outlet" (patent, paragraph [0051]).

The only objection of lack of inventive step raised by the opponent against auxiliary request A8 relies on D3 as the starting point in combination with D5 and common general knowledge.

9.3.1 D3 discloses, in addition to what has already been established in the discussion of the previous requests, a chemical descaling process as a cleaning measure for the feeding unit. The cleaning solution is discharged at the top of the tank through the steam sleeve ("Auslass 26.1.2" ["outlet"]) which is connected via a steam-feeding circuit ("Dampfleitung 28" ["steam line"]) to the baking chamber via an opening ("Dampföffnung 30" ["steam opening 30"]). To achieve this, additional water is supplied to the tank to replace the cleaning liquid. However, this fluid line formed by parts 26.1.2, 28 and 30 does not allow water to be removed from the tank. It only allows the cleaning solution to be replaced with water before steam generation is continued. Therefore, vapor sleeve 26.1.2 is not considered a "water discharge for discharging the water from the tank" in accordance with features [1.6] and [1.7].

A filter according to features [1.6] and [1.7] is undisputedly not disclosed in D3. The subject-matter of claim 1 including these features involves an inventive step for the following reasons.

9.3.2 In the written proceedings, the opponent argued that the filter device was an obvious alternative to the descaling process already disclosed in D3. In its arguments, the opponent considered it obvious to provide a filter which cleans the water entering the steam generator. Such an arrangement is, however, not claimed in claim 1 of auxiliary request 8 (see above) and it is not described in paragraphs [0049] to [0051] and Figures 3 and 4 of the patent either.

For this reason alone, this objection under Article 56 EPC against the subject-matter of claim 1 of auxiliary request A8 is not persuasive.

9.3.3 During oral proceedings before the Board the opponent for the first time submitted new arguments with respect to the objection of lack of inventive step.

They argued - at variance with their previous reasoning - that both the provision of a discharge and the provision of a filter for the discharge in accordance with features [1.6] and [1.7] were commonly known measures the skilled person would provide and did not involve an inventive step. No evidence was submitted in support of such common general knowledge.

In addition to the conditions for the introduction of new facts in oral proceedings in the absence of a duly summoned party (cf. G 4/92, see point 9.2 above), the new arguments constitute an amendment of the opponent's appeal case under Article 13(2) RPBA 2020. The opponent did not invoke special circumstances as would be required and the Board could not identify any either.

Furthermore, when also applying the criteria set out in Article 13(1) RPBA 2020, this amendment is - in the absence of evidence for common general knowledge - not suitable for resolving the issue of the opponent's unsuccessful inventive step attack in the written proceedings.

Therefore, the Board exercised its discretion and did not admit the new arguments.

9.4 It was not disputed that the amendments made to the description are allowable.

9.5 To conclude, auxiliary request A8 is allowable.