VIII. The appellant argued essentially as follows:
The invention as set out in independent claims 1 and 19 concerned a temperature-sensing field device comprising a wireless communication module and an energy conversion module. The energy conversion module converted thermal energy into electricity to power the field device. The field device provided a temperature indication based on the amount or quantity of electrical power converted, as set out in the description of the embodiment of figure 5B of the patent.
The opposition division considered the expression "the amount of electrical power" in the characterising part of claim 1 as not being unequivocally related to a measured value, and thus interpreted it as meaning the electricity itself, so that D4 (DE20107112) anticipated all of the features of claim 1.
This expression had however to be interpreted to mean a value, level, or quantity. This interpretation was evident from the claims, description and figures of the patent.
Furthermore, the pre-characterising part of claim 1 made use of the word "electricity" in the phrase "to convert thermal potential energy into electricity to power circuitry", while the characterising part of claim 1 used the words "electrical power" in the phrase "amount of electrical power converted is used to provide a temperature indication". The term "electricity" in the pre-characterizing part was indicative of a phenomenon whereas "electrical power" in the characterizing part indicated a measurable quantity. Both expressions "amount of" and "electrical power" in the characterising part of claim 1 related to a measure or quantification of the electricity, so that the claim had to be interpreted such that "amount of electrical power" referred to an amount or value, rather than the electricity itself.
The interpretation of claim 1 used by the opposition division was not in line with the invention as set out in the embodiment of the invention, as shown in figure 5B.
It was clear from figure 5A that separate energy converter and temperature sensor were present, because of the presence of the two items at the end of the thermowell 54 in figure 5A, each having separate reference numbers, and each having separate lines for connection to the electronics compartment of the field device.
It was however immediately apparent from figure 5B that only one device 72 was present at the end of the thermowell, and this device had only two lines providing signal and power (signal + power in the figure) to the electronics compartment 52 of the field device 70. From paragraphs  and  it was known that the device 70 was a temperature-sensing field device but with no separate temperature sensor. Given that the device 72 generated electricity related to the temperature to which it was exposed, the device 72 had to use some measure or assessment of the amount of electricity generated to provide the temperature indication. This was precisely the invention of claim 1.
The opposition division considered that claim 1 lacked novelty based on figure 1 of D4.
D4 disclosed a field device comprising a wireless communication module, an energy conversion module and a temperature sensor. The energy conversion module converted thermal energy into electrical energy to power a sensor and the wireless communication module.
D4 did not disclose or suggest that the "amount" (or numerical value, quantity) of electrical power converted by the energy conversion module was used to provide a temperature indication related to the thermal source. Using the correct interpretation of claim 1, wherein no sensor was required because the "temperature" related to the thermal source was derived from the value of the electrical power harvested, claim 1 was novel and inventive over D4.
Independent method claim 19 was correspondingly novel and inventive.
2. Novelty (Article 54 EPC)
2.1 The opposition division considered the subject-matter of claim 1 of the main request to be known from D4.
2.1.1 The first embodiment shown in figure 1 of document D4 is a field device reporting the temperature of a medium 3 flowing in a tube 2. It makes use of a temperature sensor 13 separate from the energy conversion module 14 (see D4, page 3, lines 17 to 19 and 29 to 32, and figure 1). Since the field device of the first embodiment of D4 does not carry out any operation other than reporting the temperature, the division concluded that the amount of energy converted by the conversion module, i.e. the thermo-elements 141, 142, could be seen as being totally provided to and used by the field device 1 to provide a temperature indication related to the thermal source.
2.1.2 Nevertheless, the board understands D4 as disclosing that the field device is provided with an energy storage element 15 constituted by either an accumulator or a high value, low loss capacitor (see D4, page 4, lines 22 to 26). The energy delivered by the thermo-elements 141-142 is first accumulated in the storage element 15 and then delivered to the field device.
The temperature reporting field device does not continuously report the temperature. The temperature is reported periodically. The energy used to power the field device at the instants during which the temperature needs be reported is provided by the storage element 15, which is able to deliver a higher amount of energy than the thermo-couple could deliver in the same given period of time (see D4, page 4, lines 28 to 31).
2.1.3 At point 12. v) of the grounds for decision, the opposition division, discussing the features of claim 1, referred to "the electrical connections in figure 1 (of D4), where the whole amount of converted thermopower from the thermoelements 141 and 142 is harvested" and considered therefore that the feature "the amount of electrical power converted by the energy conversion module is used to provide a temperature indication related to the thermal source" was known from D4.
Referring to D4, the opposition division also expressed the opinion that the amount of electrical power - either part of it or in its entirety - could be used to power the temperature sensor part of the field device and thus be used to provide the temperature indication (see last paragraph of item 12 of the grounds for decision).
2.1.4 The board understands on the other hand that in D4 the converted thermopower is not sufficient to power or supply the temperature sensor part of the field device, only the storage is able to deliver the necessary level of power. The expression of the opposition division "the whole amount of converted thermopower from the thermoelements 141 and 142 is harvested" should have therefore read: the whole amount of converted thermoenergy from the thermoelements 141 and 142 is harvested. Indeed the whole amount of energy delivered by the thermoelements of D4 is harvested to supply the field device of D4, which is the only device connected to the thermoelements 141, 142.
2.1.5 Thus, in order to reach its conclusion concerning lack of novelty, the opposition division interpreted the feature "an amount of electrical power" as meaning or being equivalent to "an amount of energy" or "an amount of electricity" to reuse the expression of the appellant.
2.1.6 However, in accordance with the established case law of the boards of appeal, when interpreting the claims, the person skilled in the art "should however try, with synthetical propensity, i.e. building up rather than tearing down, to arrive at an interpretation of the claim which is technically sensible and takes into account the whole disclosure of the patent. The patent must be construed by a mind willing to understand, not a mind desirous of misunderstanding" (see Case Law of the Boards of Appeal, 8th edition 2016, Chapter II.A.6.1, page 287).
2.1.7 Thus, in the view of the board, and for the reasons mentioned by the appellant, a person skilled in the art would have immediately understood from the application as a whole that the expression "the amount of electricity" used in original claim 17 implied that the indicated temperature was a function of the amount of electrical power converted, and not that a part of the electrical power was used to supply a temperature sensor or indicator. The person skilled in the art would also not have interpreted the expression "amount of electricity" as an "amount of energy" since an energy is a power value measured and integrated over a certain time, while a temperature value is an instantaneous value like an electrical power value. The original expression "the amount of electricity" was consequently modified and introduced in granted claims 1 and 19 in the correct form: "the amount of electrical power".
2.1.8 Hence, the board concludes that the only possible interpretation of the contested features of the characterising portions of granted claims 1 and 19, is that a temperature indication is provided on the basis of the amount or quantity of electrical power converted by the energy conversion module 38.
2.1.9 This feature is not known from D4 and therefore the subject-matter of claims 1 and 19 of the main request is novel having regard to D4 (Article 54 EPC).
VII. The respondent argues as follows:
The connection part defined in claim 1 should be interpreted as mainly having a structural function. Therefore the section depicted in figure 1 of E3 with a decreasing chord near the blade's root is not a connection part in the sense of claim 1, and thus the vortex generator is not provided in such a part. These vortex generators are furthermore attached on the suction side, and thus cannot hint to provide aerodynamic features on the pressure side as required in claim 1. None of the documents used to combine with E3, in particular E7, teaches to provide improvements to structural parts of a wind turbine blade. The gurney flaps disclosed therein are always located on aerodynamic profiles, and the skilled person does not learn that such a type of rib would increase the wind yield by providing it on a structural part.
In respect of the auxiliary request II the respondent argues that there was no occasion to file a further request, as the Board's communication did not raise any particular issues beyond those discussed in the previous proceedings. The discussion shed new light on the subject-matter and this was unexpected. The communication of the Board highlighted a different issue. The claim now makes it clearer that the rib is on the tube part of the connection part.
Reasons for the Decision
1. The appeal is admissible.
2. Subject-matter of the invention, interpretation of claim 1
2.1 The patent seeks to increase the output of a wind turbine blade without prohibitively increasing costs and without decreasing the blade's strength. It does so by the provision of an angled rib on the pressure side of the blade in the connection part of that wind turbine blade, specification paragraphs  and .
In claim 1 as granted the connection part is defined as being provided at one end with connection means, for connection to the shaft/hub of a wind turbine and delimited at the other end by a wind-energy-absorbing profile which is optimized for the wind flow. Furthermore that connection part is provided with a member comprising a rib which is defined to project from the connection part and arranged at an angle from the pressure side as recited in the characterising portion.
2.2 According to established jurisprudence on claim interpretation, the skilled person should try with synthetical propensity, to arrive at an interpretation which is technically sensible and takes into account the whole of the disclosure of a patent (Case Law of the Boards of Appeal, 8th edition, 2016, (CLBA) II.A.6.1). In this case the skilled person understands the "other end" of the connection part to be the one where the rotor blade starts to exhibit a substantially pure airfoil profile optimised for wind energy absorption. The particular shape and structure of the connection part is left undefined, and the skilled person knows that this may include various shapes ranging from a pure tubular part with a flange to a fully profiled shaped root. Therefore as interpreted from the claim's wording the connecting part merely represents the transition between the purely aerodynamic profile to an attachment ring or flange.
This otherwise clear interpretation on the basis of the wording of claim 1 or 9 itself is also supported by the description that specifies the term connection part in column 1, lines 50 to column 2, line 3, as meaning "that part of a blade that is optimized for the structure, and not so much optimized for the absorption of wind energy" and "compris[ing] the part beyond the maximum chord, in other words the part with decreasing or invariable chord". From the expression "not so much optimized" the skilled person infers that this connection part still can absorb wind energy to a certain degree. The connection part therefore comprises a transition area with mixed aerodynamic and structural properties.
Contrary to the respondent's opinion a limitation of the connection part to be one with a structural function only is neither inferred from the claim wording itself in the skilled person's understanding thereof, nor is it supported by what he gleans from the rest of the patent, in particular the above cited passage of the description.
2.3 In claims 1 and 9 the rib is defined with respect to that connection part as follows: " the connection part being provided with a member..., which member comprises a rib that projects from the connection part... said rib is arranged in a plane that forms an angle, which on the pressure side lies between 45° and 135° to the chordal plane of said wind-energy-absorbing profile."
Following established case law concerning the meaning of terms (CLBA, II.A.6.2) the fact that the connection part is "provided with" a member which "comprises" a rib does not exclude that this member or rib may also extend to another portion than the connection part of the same blade. This is indeed supported by the figures: Figure 1 shows a rib extending from a tubular portion on a trailing edge of an increasing chord portion; in Figure 3 shows the rib is provided on the tubular portion only, while in Figure 5, the rib extends on the whole length of the turbine blade, including the connection part.
3. Inventive step
3.1 The document E3 concerns a wind turbine blade with aerodynamic improving features in the form of vortex generators seeking to solve a similar technical problem and therefore represents a suitable starting point for the assessment of inventive step. Figure 1 of E3 depicts a wind turbine blade with vortex generators 3 and a connection portion. With the above understanding this connection portion includes the portion from the root referenced 12 in figure 4 to the aerodynamic portion in the region of the maximum chord as depicted in figure 1. It therefore includes the two lower vortex generators shown in figure 1 located in the transition portion from maximum chord, which indisputably must have a purely aerodynamic profile, to the lower end, where there will be no or little aerodynamic profile and which is most likely substantially cylindrical.
3.6 The respondent submits that the vortex generator depicted near the root portion of the rotor blade of E3 with decreasing chord are not provided on a connection part in the sense of claim 1 (or 9). Moreover these vortex generators are not located on the pressure side as defined in claim 1 but instead on the suction side of the blade. E7 teaches only to provide aerodynamic devices such as gurney flaps e on aerodynamic sections of a blade.
In the Board's opinion the connection part defined in claims 1 and 9 is not limited to merely having a structural function, see above. The area of the wind turbine blade with decreasing chord shown in figure 1 of E3, which has mixed aerodynamic and structural properties, is seen to be a connection part in the sense of claim 1. This connection part starts from the free end at the root and extends up to a portion located at or near the largest chord, in other words beyond the section in which the lower vortex generator is provided.
3.7 From the above it follows that the blade of a wind turbine of claim 1 and the corresponding method for producing a blade of claim 9 lack an inventive step in view of E3 in combination with the teaching of E7. Since the main request must fail on this sole ground, the Board does not need to decide on the other arguments put forward in respect of novelty or inventive step raised in respect of claims 1 and 9 of the main request.
Decision T 2456/12 (pdf) has European Case Law Identifier: ECLI:EP:BA:2017:T245612.20170602 . The file wrapper can be found here.
Decision T 59/13 (pdf) has European Case Law Identifier: ECLI:EP:BA:2017:T005913.20170428 . The file wrapper can be found here.
Photo "mystery object 7 - all the frames overlaid on each other" by David DeHetre obtained via Flickr under CC BY 2.0 license (no changes made).