United Technologies Corporation

Patent Trials and Appeals Board

Mar 25, 2022

2021004850 (P.T.A.B. Mar. 25, 2022)

UNITED STATES PATENT AND TRADEMARK OFFICE UNITED STATES DEPARTMENT OF COMMERCE United States Patent and Trademark Office Address: COMMISSIONER FOR PATENTS P.O. Box 1450 Alexandria, Virginia 22313-1450 www.uspto.gov APPLICATION NO. FILING DATE FIRST NAMED INVENTOR ATTORNEY DOCKET NO. CONFIRMATION NO. 15/783,741 10/13/2017 Jaime G. Ghigliotty 67097-2943PUS2;76161US03 5151 54549 7590 03/25/2022 CARLSON, GASKEY & OLDS/PRATT & WHITNEY 400 West Maple Road Suite 350 Birmingham, MI 48009 EXAMINER ELLIOTT, TOPAZ L ART UNIT PAPER NUMBER 3745 NOTIFICATION DATE DELIVERY MODE 03/25/2022 ELECTRONIC Please find below and/or attached an Office communication concerning this application or proceeding. The time period for reply, if any, is set in the attached communication. Notice of the Office communication was sent electronically on above-indicated "Notification Date" to the following e-mail address(es): ptodocket@cgolaw.com PTOL-90A (Rev. 04/07) UNITED STATES PATENT AND TRADEMARK OFFICE __________ BEFORE THE PATENT TRIAL AND APPEAL BOARD __________ Ex parte JAIME G. GHIGLIOTTY and MATTHEW A. DEVORE __________ Appeal 2021-004850 Application 15/783,741 Technology Center 3700 __________ Before DANIEL S. SONG, STEFAN STAICOVICI, and MICHAEL L. HOELTER, Administrative Patent Judges. HOELTER, Administrative Patent Judge. DECISION ON APPEAL STATEMENT OF THE CASE Pursuant to 35 U.S.C. § 134(a), Appellant1 appeals from the Examiner’s final decision to reject claims 1-14, 18, and 21-23. See Appeal Br. 1. We have jurisdiction under 35 U.S.C. § 6(b). 1 We use the word “Appellant” to refer to “applicant” as defined in 37 C.F.R. § 1.42 (2022). Appellant identifies “RAYTHEON TECHNOLOGIES CORPORATION” as the real party in interest. Appeal Br. 1. Appeal 2021-004850 Application 15/783,741 2 For the reasons explained below, we AFFIRM the Examiner’s rejections of these claims. CLAIMED SUBJECT MATTER The disclosed subject matter “relates to a gas turbine engine turbine stator vane with a baffle.” Spec. ¶ 2. Method claim 1 and apparatus claim 18 are independent. Claim 1 is illustrative of the claims on appeal, and is reproduced below. 1. A method of flowing cooling fluid through a stator vane in a gas turbine engine, comprising the steps of: providing an airfoil having an exterior wall providing a cooling cavity, the exterior wall has an interior surface having multiple pin fins extending therefrom; providing a baffle arranged in the cooling cavity and supported by the pin fins, wherein a perimeter cavity is provided between the baffle and the exterior wall, the pin fins arranged in the perimeter cavity; and flowing cooling fluid through a region in the perimeter cavity, the region having a low Reynolds number, wherein the pin fins are arranged in the region having a low Reynolds number and through which the cooling fluid flows; and flowing the cooling fluid to a downstream airfoil after flowing the cooling fluid through the cooling cavity. REFERENCES Name Reference Date Bunker US 6,000,908 Dec. 14, 1999 Manning et al. (“Manning”) US 2003/0133795 A1 July 17, 2003 Downs et al. (“Downs”) US 7,334,992 B2 Feb. 26, 2008 McFeat et al. (“McFeat”) US 2011/0008177 A1 Jan. 13, 2011 Malley GB 938,247 Oct. 2, 1963 Appeal 2021-004850 Application 15/783,741 3 THE REJECTIONS ON APPEAL Claims 1, 7-10, 12, 14, 18, and 21-23 are rejected under 35 U.S.C. § 103 as unpatentable over McFeat, Dimas, and Malley. Claims 2-6 are rejected under 35 U.S.C. §103 as unpatentable over McFeat, Dimas, Malley, and Bunker. Claim 11 is rejected under 35 U.S.C. § 103 as unpatentable over McFeat, Dimas, Malley, and Downs. Claim 13 is rejected under 35 U.S.C. § 103 as unpatentable over McFeat, Dimas, Malley, and Manning. ANALYSIS The rejection of claims 1, 7-10, 12, 14, 18, and 21-23 as unpatentable over McFeat, Dimas, and Malley Appellant argues these claims together. See Appeal Br. 3-4. We select independent claim 1 for review, with the remaining claims standing or falling with claim 1. See 37 C.F.R. § 41.37(c)(1)(iv) (2019). The Examiner primarily relies upon the teaching of McFeat for disclosing many of the limitations of claim 1, and particularly Figure 4 thereof which the Examiner reproduces. See Final Act. 5-6. To be clear, the Examiner relies on McFeat for disclosing “a method of flowing cooling fluid through a stator vane” whose “exterior wall has an interior surface having multiple pin fins (26, [0031]) extending therefrom.” Final Act. 5-6. However, the Examiner acknowledges that “McFeat does not disclose the Sotirios Dimas, A CFD Analysis of the Performance of Pin-Fin Laminar Flow Micro/Meso Scale Heat Exchangers, Naval Postgraduate School 1- 89 (September 2005). Appeal 2021-004850 Application 15/783,741 4 region having a low Reynolds number” as also required of claim 1.2 Final Act. 6. The Examiner relies on the teachings of Dimas for this missing limitation. See Final Act. 6-7; see also Dimas p. 8 (“in the laminar regime with Reynolds numbers in the range of 100-1,000”), p. 81 (“the laminar modeling was shown to be accurate until a Reynolds number of 1,000” and “[a]t higher values of Re there’s a likelihood of transition to turbulence”). Because Dimas also teaches that at “higher Reynolds numbers shock waves are formed” (Dimas p. 38), the Examiner reasons that it would have been obvious in view of the above teachings to flow “cooling fluid through the vane at low Reynolds numbers . . . to obtain the benefit of avoiding generation of a shockwave, as taught by Dimas.” Final Act. 7. The Examiner further acknowledges that the combination of McFeat and Dimas “does not teach flowing the cooling fluid to a downstream airfoil after [] flowing the cooling fluid through the cooling cavity” as also required of claim 1. Final Act. 7. The Examiner relies on the teachings of Malley for this limitation and provides a reason for combining such teachings with those of McFeat and Dimas. See Final Act. 8, 9. Appellant contends that “McFeat teaches away from having a low Reynolds number” (i.e., laminar flow) “as McFeat teaches that increased turbulence improves cooling effectiveness.” Appeal Br. 3 (referencing McFeat ¶ 31). The portion of McFeat referenced by Appellant teaches the use of pins “or other known features that provide improved cooling 2 Appellant’s Specification explains that a “low Reynolds number corresponds to a laminar or near-laminar flow.” Spec. ¶ 19. Appeal 2021-004850 Application 15/783,741 5 effectiveness by increasing surface area and/or promote mixing.” McFeat ¶ 31 (emphasis added); see also id. at ¶ 5. Thus, as per Appellant, McFeat “teaches adding pins 26 that will increase the Reynolds number.” Appeal Br. 3-4. The Examiner focuses upon McFeat’s “and/or” language cited above stating that improved cooling can be accomplished by “increasing surface area alone” or “by promoting turbulence” “or by both effects.” Ans. 5 (emphasis added). The Examiner further notes that McFeat also teaches alternate methods of cooling without increasing turbulence. See Ans. 5-6. For example, Paragraph 36 of McFeat teaches “‘reducing cooling effectiveness in the mid-chord region B-C’ to provide cooler cooling air to the trailing edge region D.” Ans. 5 (italics added by Examiner); see also McFeat Fig. 4. In other words, the flow of cooling fluid traveling from leading to trailing edges (A to D) can be adjusted “in order to balance heat loads and the relative cooling criticality of the leading edge A, mid chord B- C and trailing edge D regions.” McFeat ¶ 36 (referencing McFeat Fig. 4). As explained in McFeat, by “reducing cooling effectiveness in the mid- chord region B-C,” “cooling air temperature supplied to the trailing edge region D is lowered, thus . . . enabling the cooling air in the trailing edge region D to remove more heat.” McFeat ¶ 36. In addition to adjusting the cooling flow from leading edge to trailing edge, McFeat also teaches adjusting the cooling flow between the pressure and suction sides of the vane, i.e., the flow along these two sides need not be equal. See McFeat ¶ 25 (referenced at Ans. 5). In view of such alternate cooling methodologies, the Examiner states that McFeat “do[es] not require turbulent flow, even if McFeat teaches that Appeal 2021-004850 Application 15/783,741 6 turbulence improves heat transfer.” Ans. 6; see also McFeat ¶¶ 5, 31. Further, the Examiner references Dimas’s teaching that “it is much more cost effective to move upward in the diagram to a more packed configuration [of the pin fins], instead of changing the flow attributes and increasing the Reynolds number” which, as noted above, leads to turbulence. Final Act. 7 (referencing Dimas p. 63). In other words, as per the Examiner, “cooling effectiveness can be increased by increasing the number of pin fins to a tightly packed array of micro-pin fins, but keeping the Reynolds number low.” Ans. 6 (referencing Dimas p. 63). Appellant reiterates that “McFeat discusses turbulence, and discusses benefits of increasing turbulence.” Reply Br. 1. As noted above, increasing turbulence is one of the “and/or” options taught by McFeat. See McFeat ¶¶ 5, 31. However, Appellant disregards the other option taught by McFeat which is to increase surface area. Nor does Appellant address Dimas’s teaching of having a more packed pin configuration rather than increasing the Reynolds number. See above. Accordingly, and in view of the above, we are not persuaded that “McFeat teaches away from having a low Reynolds number” as Appellant asserts. Appeal Br. 3. On this point, our reviewing court has provided instruction that a teaching away requires a reference to actually criticize, discredit, or otherwise discourage investigation into the claimed solution. See In re Fulton, 391 F.3d 1195, 1201 (Fed. Cir. 2004). Here, Appellant identifies no evidence where McFeat criticizes, discredits, or otherwise discourages maintaining laminar flow. Thus, we are not persuaded the Examiner erred in combining the teachings of McFeat and Dimas. Appellant also challenges the Examiner’s reliance on Malley stating Appeal 2021-004850 Application 15/783,741 7 that directing the cooling air flow “to a downstream airfoil would change the principle of operation because the cooling fluid could not all be ejected through the trailing edge and end walls.” Appeal Br. 4; see also Reply Br. 2. The Examiner responds that there is no evidence in McFeat “that all of the air” be ejected as asserted. Ans. 7. The Examiner explains that “ejecting the used cooling air at each location is optional” and that the ejected cooling air can also “be used for further cooling.” Ans. 7 (referencing McFeat ¶ 28). Further, whatever amount of air that is ejected from McFeat’s trailing edge and end walls, “[t]he Examiner has not proposed altering the amount of cooling air ejected” therefrom. Ans. 7. In short, Appellant does not explain how directing McFeat’s ejected air for subsequent cooling would “change the principle of operation” of McFeat, which is to cool a gas turbine vane. See McFeat Title; see also Ans. 8 (“Routing cooling air from the baffle to a downstream airfoil does not interfere with the optional ejection of used cooling fluid from the trailing edge and endwalls.”). Accordingly, we are not persuaded by Appellant that the use of ejected air to cool downstream components would change the principle of operation of McFeat. We sustain the Examiner’s rejection of claims 1, 7-10, 12, 14, 18, and 21-23 as being unpatentable over McFeat, Dimas, and Malley. The Examiner’s rejection of claims 2-6 as unpatentable over McFeat, Dimas, Malley, and Bunker Appellant’s only contention is that “[t]he addition of the teachings of Bunker does not cure the above noted deficiencies with respect to McFeat, Dimas, and Malley as applied to base claim 1.” Appeal Br. 4. Appellant’s contention is not persuasive of Examiner error. We sustain the Examiner’s Appeal 2021-004850 Application 15/783,741 8 rejection of claims 2-6 as being unpatentable over McFeat, Dimas, Malley, and Bunker. The rejection of claim 11 as unpatentable over McFeat, Dimas, Malley, and Downs Claim 11 depends from claim 1 and further recites “a rib separates the cooling cavity from a trailing edge cooling cavity, wherein the rib includes holes.” Appellant contends that a skilled person “would not modify McFeat to have a rib as proposed, because McFeat teaches away from controlling cooling flow in this way and provides an alternative arrangement.” Appeal Br. 5. Appellant argues that McFeat teaches cooling “by the adjustment of cooling effectiveness rather than region specific flow rate in order to balance heat loads.” Appeal Br. 5 (referencing McFeat ¶ 36). McFeat does not clarify what is meant by “rather than region specific flow rate” when McFeat clearly teaches adjusting cooling effectiveness by adjusting the flow through regions A-D, and also between pressure and suction sides as discussed above. See McFeat ¶¶ 25, 36. There is no evidence in McFeat that additional (new) coolant is provided, only that the existing coolant is used/distributed more effectively depending on the region to be cooled. See also Ans. 9. For example, Paragraph 25 of McFeat discusses a ratio of “between 65:35 and 75:25” regarding a “cooling air flow split between the suction side wall cooling passage and the pressure side wall cooling passage.” Hence, McFeat teaches channeling different amounts of flow to different parts of the vane to achieve more effective cooling, and thus the uncertainty above regarding McFeat’s phrase “rather than region specific flow rate.” Downs also addresses cooling the “concave and convex sides” of an Appeal 2021-004850 Application 15/783,741 9 airfoil and acknowledges that “the heating from the two sides is substantially unequal.” Downs 2:7-9. Downs controls the cooling of these two sides by selective use of rib holes. See Downs 3:27-32, 4:16-25; see also Ans. 9. The Examiner reasons that it would have been obvious to use “a rib with impingement holes” as taught by Downs “in order to obtain [the] benefit of controlling the cooling of the pressure and suction sides of the vane.” Final Act. 16; see also Ans. 9. Appellant does not explain how this might be incorrect or where McFeat criticizes or discredits such modification. Accordingly, and based on the record presented, Appellant’s contention above is not persuasive of Examiner error. We sustain the Examiner’s rejection of claim 11 as being unpatentable over McFeat, Dimas, Malley, and Downs. The rejection of claim 13 as unpatentable over McFeat, Dimas, Malley, and Manning Appellant’s only contention is that “[t]he addition of the teachings of Manning does not cure the above noted deficiencies with respect to McFeat, Dimas, and Malley as applied to base claim 1.” Appeal Br. 5. Appellant’s contention is not persuasive of Examiner error. We sustain the Examiner’s rejection of claim 13 as being unpatentable over McFeat, Dimas, Malley, and Manning. DECISION SUMMARY In summary: Claim(s) Rejected 35 U.S.C. § Reference(s)/Basis Affirmed Reversed 1, 7-10, 12, 14, 18, 21-23 103 McFeat, Dimas, Malley 1, 7-10, 12, 14, 18, 21-23 Appeal 2021-004850 Application 15/783,741 10 Claim(s) Rejected 35 U.S.C. § Reference(s)/Basis Affirmed Reversed 2-6 103 McFeat, Dimas, Malley, Bunker 2-6 11 103 McFeat, Dimas, Malley, Downs 11 13 McFeat, Dimas, Malley, Manning 13 Overall Outcome 1-14, 18, 21-23 No time period for taking any subsequent action in connection with this appeal may be extended under 37 C.F.R. § 1.136(a)(1)(iv) (2022). AFFIRMED