UNITED TECHNOLOGIES CORPORATIONDownload PDFPatent Trials and Appeals BoardAug 20, 20212021000981 (P.T.A.B. Aug. 20, 2021) Copy Citation 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. 15/424,927 02/06/2017 James D. Hill 95808US01; 67097-3573US1 2213 54549 7590 08/20/2021 CARLSON, GASKEY & OLDS/PRATT & WHITNEY 400 West Maple Road Suite 350 Birmingham, MI 48009 EXAMINER NG, HENRY ART UNIT PAPER NUMBER 3741 NOTIFICATION DATE DELIVERY MODE 08/20/2021 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 JAMES D. HILL and FREDERICK M. SCHWARZ _______________ Appeal 2021-000981 Application 15/424,927 Technology Center 3700 _______________ Before NATHAN A. ENGELS, JAMES W. DEJMEK, and AMEE A. SHAH, Administrative Patent Judges. DEJMEK, Administrative Patent Judge. DECISION ON APPEAL Appellant1 appeals under 35 U.S.C. § 134(a) from a Final Rejection of claims 1, 8, and 20–23. The Final Office Action rejected then-pending claims 1–4, 6, 8–10, 12, 14, 15, 17, and 20–23. See Final Act. 1, 5–16. In an Amendment After Final (filed May 8, 2020), Appellant amended independent claim 1 to incorporate the limitations of claims 2–4 and canceled claims 2–4, 6, 9, 10, 12, 14, 15, and 17. See Amdt. 3–4. Appellant had previously canceled claims 5, 7, 11, 13, 16, 18, and 19. See Amdt. 3–5 1 Throughout this Decision, we use the word “Appellant” to refer to “applicant” as defined in 37 C.F.R. § 1.42 (2019). Appellant identifies Raytheon Technologies Corporation as the real party in interest. Appeal Br. 1. Appeal 2021-000981 Application 15/424,927 2 (filed Dec. 11, 2019). We have jurisdiction over the remaining pending claims under 35 U.S.C. § 6(b). We reverse and enter new grounds of rejection pursuant to our authority under 37 C.F.R. § 41.50(b). STATEMENT OF THE CASE Introduction Appellant’s disclosed and claimed invention generally relates to “a mixing chamber for mixing two air sources in a gas turbine engine to utilize as turbine cooling air.” Spec. ¶ 1. It is known that in a gas turbine engine, components—particularly those in the turbine section—are subjected to high temperatures. Spec. ¶¶ 4–5. Due to increased pressure in the turbine section, it is desirable to use highly pressurized air to cool the components. Spec. ¶ 5. According to the Specification, the “most pressurized air in the gas turbine engine is downstream of a high pressure compressor and it is typically hot.” Spec. ¶ 5. Thus, in order to use such highly pressurized air, it must be cooled. Spec. ¶ 6. The Specification further describes that if the air is cooled too much, it may not be effective under all conditions. Spec. ¶ 6. “Thus, it would be desirable to mix this cooling air with higher temperature air.” Spec. ¶ 6. In a disclosed embodiment, the Specification describes a gas turbine engine comprising a compressor section and a turbine section. Spec. ¶ 7. A housing surrounds the compressor and turbine sections. Spec. ¶ 7. In addition, a mixing chamber is positioned radially outwardly of the housing. Spec. ¶ 7; see also Fig. 2 (mixing chamber (116) positioned radially outwardly from housing (117)). High pressure cooling air is tapped from a Appeal 2021-000981 Application 15/424,927 3 location downstream of the compressor and is passed through a heat exchanger where it is cooled by lower pressure air passing across the heat exchanger. Spec. ¶ 7. The cooled air is passed to the mixing chamber where it is mixed with hotter air. Spec. ¶ 7. The mixed air “is returned into the housing and utilized to cool at least the turbine section.” Spec. ¶ 7. Claim 1 is illustrative of the subject matter on appeal and is reproduced below with the disputed limitations emphasized in italics: 1. A gas turbine engine comprising: a compressor section and a turbine section, said compressor section having a last compressor stage; high pressure cooling air tapped from a location downstream of said last compressor stage and passed through a heat exchanger; lower pressure air passing across said heat exchanger to cool said high pressure cooling air; a housing surrounding said compressor section and said turbine section and there being a space radially outwardly of said housing, and a mixing chamber received in said space radially outwardly of said housing, said mixing chamber connected to receive said high pressure cooling air at a location downstream of said heat exchanger, and further connected to receive air at a temperature higher than a temperature of said high pressure cooling air taken downstream of said heat exchanger; mixed air from said mixing chamber returned into said housing and utilized to cool at least said turbine section, said mixing chamber having diverters to cause a change in a flow direction of said high pressure cooling air and said air at a higher temperature; wherein said air at a higher temperature is tapped from a common point as the high pressure cooling air which is sent into said mixing chamber; wherein said high pressure cooling air is tapped from a diffuser section radially outwardly of a combustor located Appeal 2021-000981 Application 15/424,927 4 intermediate said compressor section and said turbine section; and wherein said mixed air passes through a compressor diffuser downstream of said last compressor stage. The Examiner’s Rejections2 1. Claims 1, 8, and 21–23 stand rejected under 35 U.S.C. § 103 as being unpatentable over Seitzer et al. (US 2008/0112797 A1; May 15, 2008) (“Seitzer”); Scoffone et al. (US 2017/0074106 A1; Mar. 16, 2017) (“Scoffone”); and Klingels (US 6,612,114 B1; Sept. 2, 2003). Final Act. 6–15; see also Ans. 3 (explaining that, due to Appellant’s amendments incorporating, inter alia, the limitations of then-dependent claim 4 into independent claim 1 after the Final Office Action, the rejection of claim 1 is “identical to the rejection of claim 4 in the Final Rejection”). 2. Claim 20 stands rejected under 35 U.S.C. § 103 as being unpatentable over Seitzer, Scoffone, Klingels, and Suciu et al. (US 2015/0354465 A1; Dec. 10, 2015) (“Suciu”). Final Act. 16. ANALYSIS3 Rejections of claims 1, 8, 20, and 21 In rejecting independent claim 1 (as amended by Appellant), the Examiner relies on the combined teachings of Seitzer, Scoffone, and 2 In the Advisory Action (mailed May 21, 2020), the Examiner notes that Appellant’s amendments have overcome the rejection under 35 U.S.C. § 112(b). See Advisory Act. 2. 3 Throughout this Decision, we have considered the Appeal Brief, filed August 17, 2020 (“Appeal Br.”); the Reply Brief, filed November 23, 2020 (“Reply Br.”); the Examiner’s Answer, mailed October 5, 2020 (“Ans.”); Appeal 2021-000981 Application 15/424,927 5 Klingels. See Ans. 3. We begin our analysis with a brief review of the relevant portions of these references. Seitzer recognizes that in gas turbine engines, turbine components are subjected to high temperatures and that the components may be cooled “by bleeding a portion of the pressurized air from the compressor.” Seitzer ¶ 4. Further, Seitzer describes that due to being exposed to varying temperature conditions, the turbine components may thermally expand and contract, which may affect the size of the turbine blade tip clearance with respect to the turbine shroud. Seitzer ¶ 9. Seitzer discloses that active clearance control (“ACC”) systems are known in which “relatively cool fan air or relatively hot compressor bleed air, or a mixture thereof, are channeled to the turbine case from which the shrouds are suspended,” thereby heating or cooling the turbine case, as appropriate. Seitzer ¶ 14. and the Final Office Action, mailed March 16, 2020 (“Final Act.”), from which this Appeal is taken. Appeal 2021-000981 Application 15/424,927 6 Figure 2 of Seitzer is illustrative and is reproduced below: Figure 2 of Seitzer illustrates a portion of a gas turbine engine comprising an active clearance control system. Seitzer ¶¶ 20, 35. As shown in Figure 2, high pressure cooling air (34a) is tapped from a location downstream of a last compressor stage (18) and is passed through heat exchanger (56) where the high pressure cooling air (34a) is cooled by bypass fan air (34). Seitzer ¶ 38 (additionally describing that inlet circuit (58) channels the high pressure cooling air (34a) to heat exchanger (56)). Cooled air (34b) is passed from heat exchanger (56). Seitzer ¶ 39. Seitzer also describes a compound distribution network comprising, inter alia, valves (1, 2, and 3), which are controlled by controller (68). Seitzer ¶ 48. The valves (1, 2, and 3) “control and regulate the flow through the various Appeal 2021-000981 Application 15/424,927 7 conduits of the distribution network.” Seitzer ¶ 47. More particularly the first valve (1) controls the bypass flow of the hot compressor discharge air (34a). Seitzer ¶ 49. The second valve (2) selectively controls or varies the cooled compressor discharge air (34b) from heat exchanger (56) to turbine blades (40). Seitzer ¶ 50. The third valve (3) selectively controls or varies the flow of the cooled compressor discharge air (34b) to turbine case (48). Seitzer ¶ 51. In addition to describing various modes of operation in which one of the valves is substantially fully open and the other two valves are substantially closed, Seitzer also describes the two control valves (1, 3) “control the relative amounts of the hot and cooled discharge air 34a, b.” Seitzer ¶ 60 (emphasis added). Scoffone generally relates to “mixing chambers for turbine wheel space cooling.” Scoffone ¶ 1. In describing the mixing chamber, Scoffone discloses that a first inlet tube delivers a first fluid and a second inlet tube delivers a second fluid to the mixing chamber. Scoffone ¶ 22. Scoffone describes the fluids can be purge flow or cooling flow, such as a gas (e.g., cooling air). Scoffone ¶¶ 22–23. Scoffone describes the “flow that enters the mixing chamber 130 may exit the mixing chamber 130, and the baffle plate 170 may assist in directing flow inside the mixing chamber 130 into the exit hole(s) 210.” Scoffone ¶ 23. More specifically, regarding the baffle plate, Scoffone teaches the baffle plate “may also enhance mixing within the mixing chamber 130 due to a swirl of the first fluid and the second fluid.” Scoffone ¶ 26; see also Scoffone, Fig. 4. Klingels generally relates to “a cooling air system for reducing the thermal loading on components in the turbine high-pressure region of gas Appeal 2021-000981 Application 15/424,927 8 turbines.” Klingels, col. 1, ll. 5–7. Klingels describes extracting the high- pressure air to be cooled from the compressor section and passing the air through a heat exchanger. Klingels, col. 1, ll. 18–21, col. 2, ll. 62–65. Klingels further describes that the cooled air (i.e., discharged from the heat exchanger) is guided through a control and mixing valve. Klingels, col. 4, ll. 48–52. The mixing valve also has an input for the hotter air coming from the extraction location. Klingels, col. 4, ll. 48–52. “The temperature of the cooling air emerging from the control and mixing valve may be specifically adjusted by mixing the cooled and the uncooled cooling air while varying the quantity ratio.” Klingels, col. 4, ll. 52–55. Klingels further describes the flow path of the mixed air (i.e., coming from the control and mixing valve) is “through struts of the combustion chamber diffuser” and into the turbine section. Klingels, col. 4, ll. 60–64. In the Final Action, the Examiner finds Seitzer teaches, inter alia, that high pressure cooling air is tapped from a diffuser section radially outwardly of a combustor, the high pressure cooling air is passed through a heat exchanger, and the output (cooled) air of the heat exchanger is passed to a mixing chamber along with hotter air. See Final Act. 6–10. In support, the Examiner provides an annotated version of Seitzer’s Figure 2, reproduced below, to identify the housing and mixing chamber components in Seitzer. See Final Act. 8. Appeal 2021-000981 Application 15/424,927 9 Figure 2 of Seitzer, as annotated by the Examiner, illustrates a cross- section of a housing surrounding a compressor and turbine section and a mixing chamber (illustrated as an unnumbered circle with an input of cooled air (34b) from heat exchanger (56), via valve (3) and an input of high pressure cooling air (34a), via valve (1)). See Final Act. 8. In addition to the findings of Seitzer, the Examiner finds Scoffone teaches use of diverters in a mixing chamber to “enhance mixing within the mixing chamber” and Klingels teaches passing the mixed air from the mixing chamber through a compressor diffuser downstream of the last compressor stage. See Final Act. 8–9, 12–13. Appellant disputes the Examiner’s findings that Seitzer teaches the claimed mixing chamber. Appeal Br. 3–4; Reply Br. 1. Appellant argues Appeal 2021-000981 Application 15/424,927 10 that “[t]here is no description [(in Seitzer)] that the unnumbered circle is anything other than a joint between two pipes.” Appeal Br. 3. Appellant asserts there is no need for mixing within the unnumbered circle identified by the Examiner as a mixing chamber because Seitzer describes embodiments in which only one of the three valves is fully open while the other two valves are substantially closed. Appeal Br. 4 (citing Seitzer ¶¶ 52–55). Appellant further argues that because there are not two flows presented at the same time to the unnumbered circle (i.e., the mixing chamber identified by the Examiner), there would be no need to modify Seitzer’s so-called mixing chamber to include the diverters (i.e., baffling plate) taught by Scoffone. Appeal Br. 4–5; Reply Br. 1. Still further, Appellant argues that Seitzer fails to teach the high pressure cooling air is tapped from a diffuser section radially outwardly of a combustor. Appeal Br. 3–4. We do not find these arguments persuasive of Examiner error. As discussed above, we find Seitzer describes tapping high pressure cooling air from a diffuser section radially outwardly of a combustor. See Seitzer ¶ 38, Fig. 2 (illustrating high pressure cooling air passed to heat exchanger via circuit (58)). In addition, as the Examiner explains, “the ‘diffuser section’ may be interpreted as the full-length plenum above combustor 20 of Seitzer.” Ans. 4. We agree with the Examiner that this interpretation is consistent with Appellant’s Specification and identification of housing surrounding, inter alia, a combustor section. See Ans. 4 (citing Spec., Fig. 2 (117)). As such, the high pressure cooling air is tapped from a diffuser section radially outwardly of the combustor. Appeal 2021-000981 Application 15/424,927 11 Further, we agree with the Examiner that the unnumbered circle in Figure 2 of Seitzer teaches a mixing chamber. As discussed above, Seitzer describes embodiments wherein air (34b) cooled by heat exchanger (56) via valve (3) as well as hotter, high pressure cooling air (34a) via valve (1) are input to the unnumbered circle (i.e., mixing chamber). See Seitzer ¶¶ 52–55, 60 (describing controlling relative amounts of each air input). We further note that the embodiments of Seitzer identified by Appellant do not state that only one valve is open while the others are closed. Rather, Seitzer describes a relative setting in which the valves are “substantially” open or closed— indicative of flow from a plurality of valves. See Seitzer ¶¶ 52–55. Because we find Seitzer teaches a mixing chamber for mixing two different fluids (i.e., air flows at different temperatures), we agree with the Examiner that it would have been obvious to combine Scoffone’s teaching of a baffle plate (i.e., diverter) with the mixing chamber of Seitzer “to enhance mixing,” as taught by Scoffone. See Final Act. 8–9. Appellant also asserts that Seitzer is intended to cool the turbine case for clearance control. Appeal Br. 6. As such, Appellant argues there would be no reason to modify the path of the air flow coming from the unnumbered circle in Seitzer radially inwardly through the compressor diffuser, “as it would defeat the purpose of cooling the turbine case.” Appeal Br. 6. Moreover, Appellant argues that the Examiner’s reasoning that it is merely a design choice as to how to route the air coming from the unnumbered circle of Seitzer is unsupported. Appeal Br. 6–7. In response, the Examiner explains that “having the airflow conduit pass through the compressor diffuser as opposed to the turbine case 44, or vice versa, would perform the same function and present no unexpected Appeal 2021-000981 Application 15/424,927 12 result.” Ans. 5. In addition, the Examiner finds that Appellant has not demonstrated the criticality of passing the airflow conduit through the compressor diffuser. Ans. 5. To support a conclusion that a claim is directed to obvious subject matter, i.e., that a feature is an obvious matter of design choice, the Examiner must present a “convincing line of reasoning” as to why one of ordinary skill in the art would have found the claimed feature to have been obvious. Ex parte Clapp, 227 USPQ 972, 973 (BPAI 1985). Moreover, when determining whether a rejection based on design choice is appropriate, the Examiner must review the Specification and ascertain if the limitation in question is disclosed as serving any advantage or particular purpose, or whether it solves a stated problem. The Examiner also should explain the reasoning used to determine that the prior art would have performed equally as well as the claimed invention. These two steps help present the aforementioned “convincing line of reasoning.” Clapp, 227 USPQ at 973. Here, we agree with Appellant that the Examiner has not provided any convincing line of reasoning why it would have been an obvious matter of “design choice” to alter the routing of the mixed air flow of Seitzer through the compressor diffuser, as taught by Klingels. Although there may be reasons to make such a change (e.g., to alleviate the need to route spent cooling air (34c) through the compressor diffuser where it is subsequently routed to cool the turbine blades (see Seitzer ¶¶ 39, 42, Fig. 2)), such reasoning is not on record before us. Nor has the Examiner proffered a combination of incorporating the mixing chamber of Seitzer (as modified with the diverters of Scoffone) to the system of Klingels. Although the Board is authorized to reject claims under 37 C.F.R. § 41.50(b), no inference Appeal 2021-000981 Application 15/424,927 13 should be drawn when the Board elects not to do so. See Manual of Patent Examining Procedure (“MPEP”) § 1213.02 (9th ed. Rev. 10.2019, June 2020). For the reasons discussed supra, we are persuaded of Examiner error. Accordingly, we do not sustain the Examiner’s rejection of independent claim 1. In addition, we do not sustain the Examiner’s rejections of claims 8, 20, and 21, which depend directly or indirectly therefrom. Rejection of claims 22 and 23 Claims 22 and 23 are written in dependent claim format and recite “wherein said swirl caused by said diverters provide efficient and thorough mixing of said high pressure cooling air and said air at a higher temperature.” Claim 22 purports to recite a further limitation on a gas turbine engine “as set forth in claim 14.” Similarly, claim 23 purports to recite a further limitation on a gas turbine engine “as set forth in claim 17.” In the Amendment After Final, Appellant canceled claims 14 and 17 (among others). See Amdt. 3–4. Because claims 22 and 23 depend from claims no longer pending, we pro forma reverse the Examiner’s rejection under 35 U.S.C. § 103. NEW GROUNDS OF REJECTION Pursuant to our authority under 37 C.F.R. § 41.50(b), we enter new grounds of rejection for claims 22 and 23 under 35 U.S.C. § 112(d) and 35 U.S.C. § 112(b). Appeal 2021-000981 Application 15/424,927 14 “[A] claim in dependent form shall contain a reference to a claim previously set forth and then specify a further limitation of the subject matter claimed.” 35 U.S.C. § 112(d). As discussed above, claim 22 contains a reference to claim 14 and claim 23 contains a reference to claim 17. Because the amendment canceling claims 14 and 17 was entered by the Examiner, see Advisory Act. 1, these claims are not “claim[s] previously set forth” for purposes of 35 U.S.C. § 112(d). Accordingly, we newly reject claims 22 and 23 for failing to comply with the provisions of 35 U.S.C. § 112(d). In addition, the patent statute requires that claims “particularly point[] out and distinctly claim[] the subject matter which the inventor or a joint inventor regards as the invention.” 35 U.S.C. § 112(b). Because claims 22 and 23 would incorporate by reference the limitations of claims 14 and 17, respectively—but claims 14 and 17 have been canceled—the scope of the subject matter encompassed by claims 22 and 23 cannot be determined without resorting to speculation. As such, claims 22 and 23 are indefinite. See In re Wilson, 424 F.2d 1382, 1385 (CCPA 1970) (“If no reasonably definite meaning can be ascribed to certain terms in the claim, the subject matter does not become obvious— the claim becomes indefinite.”); see also In re Steele, 305 F.2d 859, 862 (CCPA 1962). Accordingly, we newly reject claims 22 and 23 for failing to comply with the provisions of 35 U.S.C. § 112(b). Appeal 2021-000981 Application 15/424,927 15 CONCLUSION We reverse the Examiner’s decision rejecting claims 1, 8, 20, and 21 under 35 U.S.C. § 103. We reverse, pro forma, the Examiner’s decision rejecting claims 22 and 23 under 35 U.S.C. § 103. We enter a new ground of rejection rejecting claims 22 and 23 under 35 U.S.C. § 112(b). We enter a new ground of rejection rejecting claims 22 and 23 under 35 U.S.C. § 112(d). DECISION SUMMARY Claim(s) Rejected 35 U.S.C. § Reference(s)/ Basis Affirmed Reversed New Ground 1, 8, 21–23 103 Seitzer, Scoffone, Klingels 1, 8, 21– 23 20 103 Seitzer, Scoffone, Klingels, Suciu 20 22, 23 112 Indefiniteness 22, 23 22, 23 112 Improper Dependency 22, 23 Overall Outcome 1, 8, 20– 23 22, 23 TIME PERIOD FOR RESPONSE This decision contains a new ground of rejection pursuant to 37 C.F.R. § 41.50(b). Section 41.50(b) provides “[a] new ground of Appeal 2021-000981 Application 15/424,927 16 rejection pursuant to this paragraph shall not be considered final for judicial review.” Section 41.50(b) also provides: When the Board enters such a non-final decision, the appellant, within two months from the date of the decision, must exercise one of the following two options with respect to the new ground of rejection to avoid termination of the appeal as to the rejected claims: (1) Reopen prosecution. Submit an appropriate amendment of the claims so rejected or new Evidence relating to the claims so rejected, or both, and have the matter reconsidered by the examiner, in which event the prosecution will be remanded to the examiner. The new ground of rejection is binding upon the examiner unless an amendment or new Evidence not previously of Record is made which, in the opinion of the examiner, overcomes the new ground of rejection designated in the decision. Should the examiner reject the claims, appellant may again appeal to the Board pursuant to this subpart. (2) Request rehearing. Request that the proceeding be reheard under §41.52 by the Board upon the same Record. The request for rehearing must address any new ground of rejection and state with particularity the points believed to have been misapprehended or overlooked in entering the new ground of rejection and also state all other grounds upon which rehearing is sought. Further guidance on responding to a new ground of rejection can be found in the MPEP § 1214.01. No time period for taking any subsequent action in connection with this appeal may be extended. 37 C.F.R. § 1.136(a)(1)(iv); see 37 C.F.R. § 41.50(f). REVERSED; 37 C.F.R. § 41.50(b) Copy with citationCopy as parenthetical citation