T 0794/19 20-01-2022

Understanding of the feature "controlling ... in response to"

1. There was no common ground between the parties as to how the feature "the opening of said fresh air damper ... is controlled in response to a local temperature error point signal" (hereinafter: "LTEP signal") was to be construed. How this feature is understood is crucial for the present decision.

1.1 The patent proprietor interpreted features [10] to [12] of the main request not only as a direct control loop. In its view the wording described the control of the damper opening in the most generic way. As per this generic interpretation, the feature was complied with as long as the LTEP signal was input into - and the damper opening control signal was output from - a common water terminal controller (51) with a water terminal control algorithm (50). This was irrespective of whether the signals were actually in a direct cause-and-effect relationship. Therefore, even when the free cooling enable signal disabled the air damper PI control cycle, the damper opening control would still be understood as acting in response to the LTEP signal.

1.2 This interpretation of claim 1 is not persuasive and is in contradiction with the skilled person's technical understanding of the claim. The term "in response to" defines a direct cause-and-effect link between two operation parameters. In claim 1, the parameters are the LTEP signal, as the variable input signal, and the opening of the damper, as the responding output signal. Controlling the output in response to the input inherently follows an underlying control strategy (a feedback control according to a setpoint such as a PI block, value tables, switching operations, etc.), which is not further defined in claim 1. The objective of this "response" is to control the zone temperature with respect to the zone temperature setpoint by means of the damper opening. The term "in response to" thus requires that the input influences the output. A control action in which an input - though possibly hard-wired to the control unit - is systematically blocked from having any influence on the output does not qualify as "in response to" that input parameter.

1.3 In the specific context of features [10] and [11] of claim 1, therefore, a control action in which the fresh air damper is (when in the free cooling mode) always fully open, without the local temperature error point signal having any influence on it, does not qualify as being "in response to" the LTEP signal.

1.4 This understanding of the term "response" is consistent with the use of the term throughout the application as filed. A1 does not disclose the exact wording "in response to". However, the claims as originally filed define a number of cause-and-effect chains using the term "responsively":

- Claim 1: opening a fresh air damper in response to a free cooling enable signal from the building management system

- Claim 2: disabling the heating mode in response to a signal from the building management system

- Claim 4: controlling the coolant fluid flow valve in response to a local temperature error

- Claims 5, 11 and 12: minimising or controlling the speed of the cooling fan in response to an occupancy status signal of the local zone or a local air temperature threshold comparison signal

- Claim 15: changing from cooling demand mode to cooling satisfied mode in response to a "zone temperature is being reduced" signal

1.5 Were these claims interpreted such that the actions defined above as being "in response" were fully decoupled from the input, this would deprive these claims of the technical meaning they convey. The skilled person would thus not understand the terms "responsively" or "in response to" in the generic way argued by the patent proprietor.

Main request - Article 100(c) EPC

2. The decision under appeal is correct in that the ground for opposition under Article 100(c) EPC prejudices the maintenance of the patent as granted. Claim 1 of the main request includes subject-matter extending beyond the application as filed.

2.1 According to the application as filed, the fresh air damper is always in the fully open position in the free cooling mode, i.e. at all times during this mode. This was not disputed by the patent proprietor and follows from paragraph [0033] of A1, according to which the time-variable fresh air damper opening percentage signal generated by the PI block controller is replaced by setting the damper to a fully open state when the free cooling mode is enabled. This implies that in this mode the PI controller is deactivated or its output is ignored. Thus, in the free cooling mode, the damper opening is not in response to the time-variable LTEP signal (see also point 1).

2.2 Contrary to the original disclosure discussed above, the operation of the fresh air damper in the free cooling mode as defined in claim 1 (see feature [7]) is not limited to the fully open state throughout the time period of this mode. Rather, in feature [10] claim 1 encompasses a method step in which, during the free cooling mode, the opening of the damper is controlled in response to the LTEP signal, which provides the time-variable difference between the local area temperature and a setpoint of this temperature. Feature [12] unambiguously specifies that the control actions defined in features [10] and [11] are part of the free cooling mode.

2.3 Furthermore, contrary to the proprietor's interpretation, feature groups [7] to [9] and [10] to [12] do not refer to two different options for the operation mode. They are linked by the expression "and" and are thus both compulsory steps of the free cooling mode as defined in claim 1. Consequently, the free cooling mode according to claim 1 of the main request can only be construed as encompassing two different (possibly consecutive; see below) sub-modes with respect to the opening of the fresh air damper. The two sub-modes are:

- fully opening the damper in direct response to the signal from the building management system but not in response to the LTEP signal (hereinafter "control action A")

- controlling the opening in response to the LTEP signal (hereinafter: "control action B")

Control action B can include states in which the damper is temporarily fully open if the underlying control strategy generates a corresponding response. Nevertheless, this does not fall under control action A, which fully opens the damper without taking the LTEP signal into account in any way.

2.4 Control action B is not in obvious contradiction with control action A either, contrary to the patent proprietor's argument. Feature [7] solely requires that the fresh air damper is opened to a fully open position in response to the signal from the building management system which "enables" the free cooling mode (feature [5] of claim 1), i.e. at least at the point in time when the free cooling mode is triggered by the signal. This wording does not specify that the open position of the damper is maintained throughout the free cooling mode. The step of initially completely opening the damper according to control action A is a feasible starting point for the subsequent control of the opening in accordance with control action B (e.g. the starting point with the lowest air flow resistance). Since the wording of the claim is clear as such, there is no need to further rely on the description when construing the claimed subject-matter.

2.5 The only disclosure of control action B, i.e. of the control of the damper opening in connection with the LTEP signal 210 is found in paragraph [0033] of A1, which states that the "water terminal control algorithm takes the aforementioned signals" (which include is the LTEP signal) and "logically processes them to yield" inter alia a damper percentage signal. However, as explained above, this control action is disclosed here as not being carried out during the free cooling mode. For this reason alone, the subject-matter of claim 1, which defines control action B as being active in the free cooling mode, is unallowably extended.

2.6 Apart from this, the control of the damper according to paragraph [0033] is only disclosed as part of a logical processing which uses further signals fed to the water terminal controller "to yield a fresh air damper signal". These signals include the occupancy status and the temperature error threshold. However, none of these further signals is present in features [10] to [12] of claim 1, and this omission constitutes an unallowable intermediate generalisation. Thus, there is no unambiguous disclosure of a cause-and-effect link ("in response to") only for the parameters LTEP signal and damper opening percentage.

2.7 To conclude, adding features [10] and [11] extends the subject-matter of claim 1 beyond the subject-matter of the application as filed.

First and second auxiliary requests - admittance

3. The first and second auxiliary requests correspond to the first and second auxiliary requests which were the subject of the decision under appeal. Furthermore, they were submitted with the statement of grounds of appeal. They are therefore part of the proceedings and the Board has no discretion to hold them inadmissible under Article 12(4) RPBA 2007.

3.1 The question of the extent to which the patent proprietor defended auxiliary request 1 in oral proceedings is irrelevant since this request was not withdrawn.

3.2 The patent proprietor's request to maintain the patent on the basis of the second auxiliary request corresponds to the patent as maintained in amended form. This is equivalent to a request to dismiss the opponent's appeal and is a perfectly valid reaction to that appeal. It is not to be considered in the framework of the patentee's own appeal, where, if the patent proprietor were the sole appellant, it would serve no purpose, since the Board would have no jurisdiction in the matter. It follows that there is no inconsistency, contrary to the opponent's submission.

First auxiliary request - Article 123(3) EPC

4. The scope of protection is unallowably extended by the subject-matter of claim 1 of auxiliary request 1, in violation of the requirements of Article 123(3) EPC.

4.1 In the first auxiliary request, the control action B of controlling the damper in response to the LTEP signal is replaced with the statement "during the free cooling mode, with said fresh air damper in the fully open position", i.e. a "control action C" in which the damper is not controlled in response to the LTEP signal throughout the free cooling mode. The patent proprietor's argument that this constituted a restriction of scope versus the subject-matter of claim 1 of the main request is not convincing.

Control action C cannot be considered a special case of of the control "in response to the LTEP signal" (control action B) in which the LTEP signal is no longer used as an input. The fact that all the control signals are input and processed in the water terminal controller by means of an algorithm, as shown in Figure 2 of A1, is of no relevance since in the free cooling mode (according to paragraph [0033] of the application as filed) the LTEP signal 210 and the fresh air damper signal 217 do not interact in this algorithm. Therefore, contrary to the conclusion in the decision under appeal, the control of the damper opening is not disclosed as always being at least dependent on (i.e. "in response to") the LTEP signal. Specifically, it is not disclosed as being dependent on the LTEP signal during the free cooling mode.

4.2 Thus, control action C is not a sub-mode with respect to control action B but a different operation mode. While deleting control action B is an extension of protection, introducing control action C is shifting the protection to different subject-matter. Thus, the amendment made to feature [10'] results in an aliud with respect to feature [10] of the main request and violates the requirements of Article 123(3) EPC (see Case Law of the Boards of Appeal, 9th edition, 2019, II.E.2.4.13).

4.3 Under these circumstances it is irrelevant whether control action C has a basis in the application as filed and complies with the requirements of Article 123(2) EPC. Deleting the added matter "control action B" inevitably results in an infringement of Article 123(3) EPC. On the other hand, as control action B was not originally disclosed for the free cooling mode, it cannot be defined in the claim without violating the requirements of Article 123(2) EPC. This situation is commonly described as an "inescapable trap" (see G 1/93, Reasons 13).

4.4 The patent proprietor argued that under Article 69(1) second sentence, EPC the description had to be considered when determining the extent of protection and that in doing so the skilled person would conclude that the now omitted feature "controlling the damper opening in response to the LTEP signal" (control action B) was to be interpreted differently. In the process, the skilled person would have realised that the wording of the patent as granted was unclear and needed to be understood in consideration of the description.

4.5 This argument is not persuasive. Under Article 69(1) EPC, the extent of the protection conferred by a European patent shall be determined by the claims. It is true that the second sentence of Article 69(1) EPC states that the description and drawings are to be be used to interpret the claims. However, as set out above (see point 1.), the term "in response to" as used in claim 1, has an unambiguous and generally accepted meaning for the skilled person. This understanding cannot be superseded by a different definition found in the description. If the intention was to give a new meaning to this clear wording, which was in no need of any interpretation, then a respective definition to that effect should have been included in the claim (see Case Law of the Boards of Appeal, 9th edition 2019, II.E.2.3.1 and also T 177/08, Reasons 3.3).

Second auxiliary request - Article 123(3) EPC

5. Since claim 1 no longer includes control action B but instead control actions A and C (see features [109b], [110] and [111]), this results in the same extension of protection as for the first auxiliary request (see point 4.). This cannot be resolved by the newly added details of the water terminal control algorithm. Control action B is still omitted compared with the patent as granted.

Therefore, also claim 1 of the second auxiliary request is not in line with the requirements of Article 123(3) EPC either.

Fourth to twelfth auxiliary requests - admittance

6. By letter dated 13 July 2021, the patent proprietor submitted new fourth to twelfth auxiliary requests to replace the fourth to ninth auxiliary requests as submitted with the statement of grounds of appeal.

6.1 Since the summons to oral proceedings was notified after the date of entry into force of the RPBA 2020, Article 13(2) RPBA 2020 applies (Articles 25(1) and (3) RPBA 2020).

6.2 The new fourth to twelfth auxiliary requests are an amendment to the patent proprietor's appeal case as per Article 13(2) RPBA 2020 and the admittance of these requests is at the Board's discretion. At the third level of the convergent approach (see document CA/3/19, page 43, explanatory remarks on Article 13(2) RPBA 2020) in exercising its discretion the Board may also rely on criteria applicable at the second level, which includes the question of whether the amendments prima facie overcome the issues raised (see Article 13(1) RPBA 2020).

6.3 For the fourth to twelfth auxiliary requests this is not the case. In claim 1 of the fourth to twelfth auxiliary requests, control action B is - as in the second auxiliary request - no longer present (see features [109b', 109b''] to [112', 112'']).

6.4 Features [111', 111''] now recite the PI damper opening control loop as being part of the water terminal control algorithm as disclosed in paragraph [0033] of A1. However, all the details given in feature groups [111'] and [111''] cannot change the fact that feature groups [109b',109b''] imply that the damper is and remains fully open during the free cooling mode and that there is thus no control in response to the LTEP signal (i.e. control action B is still omitted). As such, even though different wording with more details of the control algorithm has been relied upon, the protection is still extended with respect to claim 1 as granted due to the omission of control action B and the shift to different subject-matter.

6.5 Due to this immediately apparent extension of protection in claim 1 of each of the fourth to twelfth auxiliary requests, none of these requests is taken into account in the appeal proceedings (Article 13(2) RPBA).

7. To conclude, the patent proprietor's claim requests do not comply with the requirements of either Article 123(2) EPC or Article 123(3) EPC, or are not admitted due to their prima facie unallowability. Therefore, the opponent's appeal is allowable and the patent proprietor's appeal is not.