T 1186/20 - Steam ovens and laundry machines

Key points

• A decision with a certain Paper C vibe.
• Claim 1 is directed to an oven for baking food products with a feeding unit for feeding steam into the baking chamber, wherein the feeding unit comprises an air trap and wherein a tank is used with two shells that are permanently joined to each other.
• The opposition was based on lack of inventive step, including obviousness over D3. The opponent in appeal argues that D3 is novelty-destroying.
• "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 [over D3]." (This could be a question for EQE Paper D).
• D3 does not disclose the air trap and does not disclose the feature of two shells that are permanently joined.
• "the distinguishing features have to be grouped and relate to the following different (partial) technical problems"
• "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."
• "The patent proprietor argued that the skilled person would not consider the teaching of D5 [about an air trap] 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. "
• "... 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."
• "To conclude, [the air trap feature] is obvious in view of the disclosure of D5."
• Turning to the second feature: "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."
• "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."
• Auxiliary request 8 is allowable, however. 

EPO 

The link to the decision is provided after the jump, as well as (an extract of) the decision text.

https://www.epo.org/en/boards-of-appeal/decisions/t201186eu1

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.