CTNF 18/917,168 CTNF 90892 DETAILED ACTION 07-03-aia AIA 15-10-aia The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA. Claim 1-18 are currently pending in the application. Priority 02-25 AIA Acknowledgment is made of applicant's claim for foreign priority based on an application filed in the United Kingdom of Great Britain and Northern Ireland (GB) on 11/13/2023 . It is noted, however, that applicant has not filed a certified copy of the GB 2317342.0 application as required by 37 CFR 1.55. Specification 07-29 AIA The disclosure is objected to because of the following informalities: The title of the invention is not descriptive. A new title is required that is clearly indicative of the invention to which the claims are directed. The following title is suggested: GAS TURBINE ENGINE HYDROGEN FUEL SYSTEM WITH AUXILIARY PRE-HEAT COMBUSTOR AND FUEL INJECTOR FEED-ARM HEAT EXCHANGER . Applicant is reminded of the proper content of an abstract of the disclosure. A patent abstract is a concise statement of the technical disclosure of the patent and should include that which is new in the art to which the invention pertains. The abstract should not refer to purported merits or speculative applications of the invention and should not compare the invention with the prior art. If the patent is of a basic nature, the entire technical disclosure may be new in the art, and the abstract should be directed to the entire disclosure. If the patent is in the nature of an improvement in an old apparatus, process, product, or composition, the abstract should include the technical disclosure of the improvement. The abstract should also mention by way of example any preferred modifications or alternatives. Where applicable, the abstract should include the following: (1) if a machine or apparatus, its organization and operation; (2) if an article, its method of making; (3) if a chemical compound, its identity and use; (4) if a mixture, its ingredients; (5) if a process, the steps. Extensive mechanical and design details of an apparatus should not be included in the abstract. The abstract should be in narrative form and generally limited to a single paragraph within the range of 50 to 150 words in length. See MPEP § 608.01(b) for guidelines for the preparation of patent abstracts. The abstract of the disclosure is objected to because the content of the Abstract appears to be directed towards a different invention, describing an “ exhaust passage ” that is “ configured to conduct combustion products from the auxiliary combustor to the core combustor ”. The Abstract appears to be the Abstract for co-pending application 18/917,212 “Gas Turbine Engine Fuel System” . The Abstract as filed fails to include a concise statement of the technical disclosure of the instant application (e.g. it fails to describe “ a first heat exchanger configured to exchange heat between hydrogen fuel in the main conduit and auxiliary combustor exhaust gases ”, or “ a second heat exchanger provided within the injector feed-arm and configured to exchange heat between hydrogen fuel and auxiliary combustor exhaust gases ” recited in claim 1). A corrected abstract of the disclosure is required and must be presented on a separate sheet, apart from any other text. See MPEP § 608.01(b) . Appropriate correction is required. Claim Objections 07-29-01 AIA Claim s 2-11, 14-16 are objected to because of the following informalities: In Claims 2-11 , the preamble should be revised to state: -- [[A]] The fuel system according to--; In claim 3 , line 4, “combustion products from the auxiliary combustor” should be revised to: -- combustion products from the auxiliary combustor exhaust gases --, for sake of consistency with how the limitation is recited in claim 1, lines 9-10; Claim 7 , line 1, “wherein the or each injector” should be revised to: --wherein the or each fuel injector--, since only a singular “fuel injector” has been introduced in claim 1, with no implication of multiple injectors to necessitate “each injector” in the claim; Claim 8 , line 1, “wherein the or each injector” should be revised to: --wherein the or each fuel injector--, since only a singular “fuel injector” has been introduced in claim 1, with no implication of multiple injectors to necessitate “each injector” in the claim; In claims 14-16 , the preamble should be revised to state: -- [[A]] The method according to --. Appropriate correction is required. Claim Rejections - 35 USC § 112 07-30-02 AIA The following is a quotation of 35 U.S.C. 112(b): (b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention. The following is a quotation of 35 U.S.C. 112 (pre-AIA), second paragraph: The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention. 07-34-01 AIA Claim s 4, 13-17 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor, or for pre-AIA the applicant regards as the invention. Claim 4 , line 4, recites “ combustion products ”. It is unclear whether this limitation is meant to be referring to the “ auxiliary combustor exhaust gases ” introduced in claim 1 (referred to as “ combustion products from the auxiliary combustor ” in claim 3), or if it is referring to wholly different and separate “ combustion products ” (e.g. combustion products of the core combustor). Claim 13 , the last 2 lines, recites “ the injector feed-arm ”. There is insufficient antecedent basis for this limitation in the claim. No “ injector feed-arm ” was previously introduced, hence its relationship to the other limitations in the claim is unclear. Claim 14 , lines 2-3, recites “ the first exhaust passage ”. There is insufficient antecedent basis for this limitation in the claims. No exhaust passage was previously introduced in the claims, hence its relationship to the other limitations in the claim is unclear. Claims 15-17 are rejected by virtue of dependence on claim 13. Double Patenting 08-33 AIA The nonstatutory double patenting rejection is based on a judicially created doctrine grounded in public policy (a policy reflected in the statute) so as to prevent the unjustified or improper timewise extension of the “right to exclude” granted by a patent and to prevent possible harassment by multiple assignees. A nonstatutory double patenting rejection is appropriate where the conflicting claims are not identical, but at least one examined application claim is not patentably distinct from the reference claim(s) because the examined application claim is either anticipated by, or would have been obvious over, the reference claim(s). See, e.g., In re Berg , 140 F.3d 1428, 46 USPQ2d 1226 (Fed. Cir. 1998); In re Goodman , 11 F.3d 1046, 29 USPQ2d 2010 (Fed. Cir. 1993); In re Longi , 759 F.2d 887, 225 USPQ 645 (Fed. Cir. 1985); In re Van Ornum , 686 F.2d 937, 214 USPQ 761 (CCPA 1982); In re Vogel , 422 F.2d 438, 164 USPQ 619 (CCPA 1970); In re Thorington , 418 F.2d 528, 163 USPQ 644 (CCPA 1969). A timely filed terminal disclaimer in compliance with 37 CFR 1.321(c) or 1.321(d) may be used to overcome an actual or provisional rejection based on nonstatutory double patenting provided the reference application or patent either is shown to be commonly owned with the examined application, or claims an invention made as a result of activities undertaken within the scope of a joint research agreement. See MPEP § 717.02 for applications subject to examination under the first inventor to file provisions of the AIA as explained in MPEP § 2159. See MPEP § 2146 et seq. for applications not subject to examination under the first inventor to file provisions of the AIA. A terminal disclaimer must be signed in compliance with 37 CFR 1.321(b). The filing of a terminal disclaimer by itself is not a complete reply to a nonstatutory double patenting (NSDP) rejection. A complete reply requires that the terminal disclaimer be accompanied by a reply requesting reconsideration of the prior Office action. Even where the NSDP rejection is provisional the reply must be complete. See MPEP § 804, subsection I.B.1. For a reply to a non-final Office action, see 37 CFR 1.111(a). For a reply to final Office action, see 37 CFR 1.113(c). A request for reconsideration while not provided for in 37 CFR 1.113(c) may be filed after final for consideration. See MPEP §§ 706.07(e) and 714.13. The USPTO Internet website contains terminal disclaimer forms which may be used. Please visit www.uspto.gov/patent/patents-forms. The actual filing date of the application in which the form is filed determines what form (e.g., PTO/SB/25, PTO/SB/26, PTO/AIA/25, or PTO/AIA/26) should be used. A web-based eTerminal Disclaimer may be filled out completely online using web-screens. An eTerminal Disclaimer that meets all requirements is auto-processed and approved immediately upon submission. For more information about eTerminal Disclaimers, refer to www.uspto.gov/patents/apply/applying-online/eterminal-disclaimer. 08-35 AIA Claim s 1-3, 5, 7-12 are provisionally rejected on the ground of nonstatutory double patenting as being unpatentable over claim s 1-7, 9-14 of copending Application No. 18/917,212 (reference application, published as US 2026/0110269 A1, henceforth Ravikanti ) . Although the claims at issue are not identical, they are not patentably distinct from each other because they are directed to the same subject matter. Regarding independent claim 1 , Ravikanti claims a fuel system for a hydrogen-fuelled gas turbine engine comprising: a main fuel conduit configured to conduct hydrogen fuel from a hydrogen storage unit to a core combustor of the gas turbine engine ( claim 1 , verbatim); a pre-heater comprising an auxiliary combustor configured to combust hydrogen fuel diverted from the main fuel conduit to heat hydrogen fuel in the main fuel conduit ( claim 1 , verbatim); a first heat exchanger configured to exchange heat between hydrogen fuel in the main conduit and auxiliary combustor exhaust gases ( claim 7 ); and a fuel injector comprising a fuel spray nozzle projecting from an injector feed-arm ( claims 2-3 ); wherein the fuel system comprises a second heat exchanger provided within the injector feed-arm and configured to exchange heat between hydrogen fuel and auxiliary combustor exhaust gases ( claims 4-5, implied by the recitation of first and second passages in the feed-arm that are in thermal communication, carrying hydrogen fuel and the auxiliary combustor exhaust gas). Regarding claim 2 , Ravikanti claims the fuel system according to claim 1, wherein the second heat exchanger is provided downstream in hydrogen fuel flow and auxiliary combustor exhaust flow of the first heat exchanger ( claim 4 & 5 , the second heat exchanger is described as being in the feed-arm of the fuel injector, which would be downstream of the pre-heater forming the first heat exchanger). Regarding claim 3 , Ravikanti claims the fuel system according to claim 1 wherein the second heat exchanger comprises a first passage configured to conduct hydrogen fuel to the core combustor and a second passage configured to conduct combustion products from the auxiliary combustor to the core combustor of the gas turbine engine ( claims 4-5 ). Regarding claim 5, Ravikanti claims the fuel system according to claim 3, wherein the first and second passages are coaxial, with the first passage being provided within the second passage ( claim 6 ). Regarding claim 7 , Ravikanti claims the fuel system according to claim 1, wherein the or each injector comprises a plurality of spray nozzles ( claims 2 & 9 ). Regarding claim 8 , Ravikanti claims the fuel system according to claim 7, wherein the or each injector comprises a first set of spray nozzles in fluid communication with the first passage, and a second set of spray nozzles in fluid communication with the second passage ( claim 10 ). Regarding claim 9 , Ravikanti claims the fuel system according to claim 8, wherein the second set of spray nozzles is provided at least part annularly around the first set of spray nozzles ( claim 11 ). Regarding claim 10 , Ravikanti claims the fuel system according to claim 1, wherein the auxiliary combustor comprises a second exhaust passage configured to direct auxiliary combustor exhaust flow to a second outlet, bypassing the gas turbine engine core combustor ( claim 12 ). Regarding claim 11 , Ravikanti claims the fuel system according to claim 1, wherein the fuel system comprises an exhaust valve configured to control exhaust flow through the first exhaust passage ( claim 13) . Regarding claim 12 , Ravikanti claims the gas turbine engine comprising a fuel system in accordance with claim 1 ( claim 14 ). Claims 13-17 are provisionally rejected on the ground of nonstatutory double patenting as being unpatentable over claims 1-7, 9-14 of copending Application No. 18/917,212 (reference application, published as US 2026/0110269 A1, henceforth Ravikanti ), further in view of . Regarding independent claim 13 , Ravikanti claims a method of operating a fuel system of a hydrogen fuelled gas turbine engine comprising: operating a core combustor to combust hydrogen fuel ( claim 1 , the method step is inferred by the recitation of “ a main fuel conduit configured to conduct hydrogen fuel from a hydrogen storage unit to a core combustor of the gas turbine engine ”); diverting a portion of hydrogen fuel flow upstream of the core combustor in hydrogen fuel flow, and combusting the diverted portion in an auxiliary combustor (claim 1, inferred by “ an auxiliary combustor configured to combust hydrogen fuel diverted from the main fuel conduit to heat hydrogen fuel in the main fuel conduit ”) ; and exchanging heat between auxiliary combustor exhaust gases and hydrogen fuel flow in a first heat exchanger ( claim 7 , inferred by “ a heat exchanger configured to exchange heat between hydrogen fuel in the main fuel conduit, and auxiliary combustor exhaust gases ”); and exchanging heat between auxiliary combustor exhaust gases and hydrogen fuel flow in a second heat exchanger provided within the injector feed-arm ( claims 4-5 , inferred by “ the feed-arm comprises a first passage configured to conduct hydrogen fuel to the fuel spray nozzle, and a second passage configured to conduct auxiliary combustor exhaust gases to the fuel spray nozzle ”, “ the first passage is in thermal communication with the second passage, such that heat from the auxiliary combustor exhaust gases is transmitted to the fuel within the first passage ”). Ravikanti fails to explicitly claim the operating the core combustor to combust hydrogen fuel is in a core compressor air flow (more likely than not, the core combustor will combust hydrogen fuel in a core compressor air flow, as such a step is routine in the art of gas turbine engines). Roberge teaches operating a core combustor 24 to combust hydrogen fuel 46 (Para. 0020) in a core compressor air flow (from compressor 20, 22, Para. 0013). Therefore it would have been obvious to one of ordinary skill in the art at the time the invention was filed to have modified the invention claimed by Ravikanti, such that the core combustor combusts the hydrogen fuel in a core compressor air flow, in order to provide an oxidizer for the hydrogen fuel in the form of high-pressure airflow that can be mixed with the fuel to generate the combustion gases (Roberge Para. 0013). Such an operation is well-known and common in the art of gas turbine engines. Regarding claim 14 , Ravikanti in view of Roberge claims the method according to claim 13, and Ravikanti further claims wherein the method comprises operating a valve configured to control flow through the first exhaust passage ( claim 13 , inferred by “ an exhaust valve configured to control exhaust flow through the first exhaust passage ”; see also claim 16). Regarding claim 15 , Ravikanti in view of Roberge claims the method according to claim 14, and Ravikanti further claims wherein the method comprises controlling the valve such that a main gas turbine engine NOx emissions target is met ( claim 17 ). Regarding claim 16 , Ravikanti in view of Roberge claims the method according to claim 15, and Ravikanti further claims wherein the method comprises operating the auxiliary combustor such that a main gas turbine engine NOx emissions target is met ( claim 18 ). Regarding claim 17 , Ravikanti in view of Roberge claims a control system configured to operate the fuel system in accordance with claim 13 ( claim 19 ) . This is a provisional nonstatutory double patenting rejection because the patentably indistinct claims have not in fact been patented. Allowable Subject Matter Claims 1-3, 5, 7-12 would be allowable if rewritten or amended to overcome the rejections under non-statutory double patenting, or a timely Terminal Disclaimer filed. Claims 4, 13-17 would be allowable if rewritten or amended to overcome the rejection(s) under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA), 2nd paragraph, set forth in this Office action, and to overcome the rejections under non-statutory double patenting presented above, or a timely Terminal Disclaimer filed. 12-151-08 AIA 07-43 12-51-08 Claim 6 is objected to as being dependent upon a rejected base claim, but would be allowable if rewritten in independent form including all of the limitations of the base claim and any intervening claims. Pertinent Prior Art The prior art made of record on the attached PTO-892 and not relied upon is considered pertinent to applicant's disclosure for teaching various prior art arrangements of fuel systems having a heat exchanger integrated into an injector feed-arm, and arrangements for preheating a fuel using a portion of fuel diverted from a main conduit. Contact Information Any inquiry concerning this communication or earlier communications from the examiner should be directed to ALAIN CHAU whose telephone number is (571)272-9444. The examiner can normally be reached on M-F 9am-6pm PST. Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice. If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Devon Kramer can be reached on 571 272 7118. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300. Information regarding the status of an application may be obtained from the Patent Application Information Retrieval (PAIR) system. Status information for published applications may be obtained from either Private PAIR or Public PAIR. Status information for unpublished applications is available through Private PAIR only. For more information about the PAIR system, see http://pair-direct.uspto.gov. Should you have questions on access to the Private PAIR system, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative or access to the automated information system, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000. /ALAIN CHAU/Primary Examiner, Art Unit 3741 Application/Control Number: 18/917,168 Page 2 Art Unit: 3741 Application/Control Number: 18/917,168 Page 3 Art Unit: 3741 Application/Control Number: 18/917,168 Page 4 Art Unit: 3741 Application/Control Number: 18/917,168 Page 5 Art Unit: 3741 Application/Control Number: 18/917,168 Page 6 Art Unit: 3741 Application/Control Number: 18/917,168 Page 7 Art Unit: 3741 Application/Control Number: 18/917,168 Page 8 Art Unit: 3741 Application/Control Number: 18/917,168 Page 9 Art Unit: 3741 Application/Control Number: 18/917,168 Page 10 Art Unit: 3741 Application/Control Number: 18/917,168 Page 11 Art Unit: 3741 Application/Control Number: 18/917,168 Page 12 Art Unit: 3741 Application/Control Number: 18/917,168 Page 13 Art Unit: 3741
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