DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
This is in response to the correspondence filed on 2/18/2026.
Continued Examination Under 37 CFR 1.114
A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on 2/18/2026 has been entered.
Specification
The disclosure is objected to because of the following informalities:
The specification uses number 134 to refer to different elements: Page 5, lines 27-28 “a third fuel line 134”, and the same number 134 later appears on page 6 line 11 describe “a volume 134” and “the first volume 134” on line 14 of the same page 6.
Appropriate correction is required.
Claim Rejections - 35 USC § 112
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.
Claim 1, and dependent claims, 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 applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
Claim 1 recites the limitation " the first and second vaporisers”. There is insufficient antecedent basis for this limitation in the claim.
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claim(s) 1-2, 6, 11-13, 17-22 is/are rejected under 35 U.S.C. 103 as being unpatentable over Boucher 20210340908 in view of Brady 11946419 and Tanaka WO 2016047109
Regarding claim 1, Boucher teaches:
A propulsion system comprising:
(i) a propulsive hydrogen-burning (hydrogen [0037]) gas turbine engine (inter alia, Fig 1-4);
(ii) a hydrogen-fuelled auxiliary power unit (“auxiliary power unit 450 may be a fuel cell APU (as shown) or as a Brayton cycle system (e.g., combustion with a turbine)” [0052]);
(iii) a first tank arranged to store liquid hydrogen (a cryogenic fuel tank 422)
(iv) a first fuel line (inter alia, 426, 428) arranged to transport hydrogen from the first tank to a combustion apparatus of the gas turbine engine, the first fuel line including a first fuel pump (one or more pumps for working fluids and/or fuels may be employed in the flow lines, as will be appreciated by those of skill in the art. [0046]) and a first vaporiser (heat exchanger 432, 442); and
(v) a second fuel line (Intier alia, 444) arranged to transport hydrogen from the first tank to the auxiliary power unit, the second fuel line including a second fuel pump (one or more pumps for working fluids and/or fuels may be employed in the flow lines, as will be appreciated by those of skill in the art [0046]) and a second vaporiser (“In the third flow supply line 444, the fuel from the cryogenic fuel tank 422 may be directed by the flow controller 424 to a regulator 446. The regulator 446 may be a pressure and/or temperature regulator that can condition the fuel as it flows along the third flow supply line 444.” [0052], where pressure and temperature regulations are known to be accomplished in such circuits by pumps, heat exchangers/vaporizers; to clear any doubt, Boucher teaches 2 separate lines, each with a heat exchanger/vaporizer as evidenced in Fig. 2- 240 and 232, Fig. 3 342 and 332, Fig. 4 442 and 432 )
wherein the first fuel pump and the second fuel pump (pumps as discussed above) are arranged to provide the liquid hydrogen (422 is a cryogenic fuel tank [0050]) from the first tank to the first and second vaporisers (inter alia, 432, 446, 442, Fig. 4, as discussed above), respectively, and the first and second vaporisers are arranged to receive and vaporise the liquid hydrogen from the first fuel pump and the second fuel pump (pumps and vaporisers as discussed above, and vaporisers are known to vaporize liquid hydrogen), and provide resulting gaseous hydrogen to the combustion apparatus (412) and to the auxiliary power unit (450), respectively (422 contains cryogenic fuel [0050]; Fig. 4)
Boucher teaches the first fuel line arranged to transport hydrogen from the first tank to a combustion apparatus of the gas turbine engine, the first fuel line including a first fuel pump and a first vaporiser (as discussed above), second fuel line arranged to transport hydrogen from the first tank to the auxiliary power unit, the second fuel line including a second fuel pump (as discussed above). Boucher is silent about:
(vi) a second tank arranged to store compressed gaseous hydrogen;
(vii) a third fuel line arranged to convey gaseous hydrogen between the second tank and the first fuel line at a position thereon between the first vaporiser and the combustion apparatus; and
(viii) a nitrogen storage tank arranged to store compressed gaseous nitrogen,
wherein the propulsion system further comprises apparatus arranged to selectively convey the gaseous nitrogen from the nitrogen storage tank and the gaseous hydrogen from the second tank to at least one of
(a) a position on the first fuel line between the first fuel pump and the first vaporiser; and
(b) a position on the second fuel line between the second fuel pump and the second vaporiser.
However, Brady 11946419 teaches:
(vi) a second tank (304 in Fig. 3) arranged to store compressed gaseous hydrogen (a second tank arranged to store compressed gaseous hydrogen, Col 8 ll. 17-20)
(vii) a third fuel line (labeled in the image below) arranged to convey gaseous hydrogen between the second tank (304) and the first fuel line (labeled in the Image below)
Regarding the limitation “at a position thereon between the first vaporiser and the combustion apparatus”, this is recognized as a Rearrangement of parts, see MPEP 2144.04(VI)(C) In re Japikse, 181 F.2d 1019, 86 USPQ 70 (CCPA 1950) (Claims to a hydraulic power press which read on the prior art except with regard to the position of the starting switch were held unpatentable because shifting the position of the starting switch would not have modified the operation of the device.); In re Kuhle, 526 F.2d 553, 188 USPQ 7 (CCPA 1975) (the particular placement of a contact in a conductivity measuring device was held to be an obvious matter of design choice).
(viii) a nitrogen storage tank arranged to store compressed gaseous nitrogen (306, “an inert gas (e.g., nitrogen, helium, etc.)” Col 4 ll. 63-64),
wherein the propulsion system further comprises apparatus (image below) arranged to selectively (as selected by, inter alia, 310 and 312) convey the gaseous nitrogen from the nitrogen storage tank (see Fig. 3) and the gaseous hydrogen from the second tank (see Fig. 3) to at least one of
(a) a position on the first fuel line between the first fuel pump (334) and the first vaporiser (see Fig. 3, conenection between pump 334 and vaporizer 344);
It would have been obvious to a person having ordinary skills in the art before the effective filing date of the claimed invention to provide Boucher with Brady's teachings discussed above in order “to purge the fuel circuit 210 before the turbofan engine 200 accepts a load, the valve controlling circuitry 410 opens at least the first valve 310 to induce the inert gas through the fuel circuit 210. In some other examples, the fuel circuit 210 is already filled with the inert gas from a purge during a previous shutdown operation. In such examples, the valve controlling circuitry 410 opens at least the second valve 312 while the first valve 310 may remain closed to enable the hydrogen from the first hydrogen supply 304 to flush the inert gas out of the fuel circuit 210” as taught by Brady Col 14 ll. 1-15.
Boucher in view of Brady is silent about an ullage as claimed, and the duct connecting a fuel line to the ullage as claimed.
wherein the propulsion system further comprises a first duct connecting the second fuel line at a position thereon between the second vaporiser and the auxiliary power unit to the ullage of the first tank,
Tanaka teaches a hydrogen fuel supply system (abstract), and:
a duct (inter alia, 75, Fig. 4) connecting the second fuel line (83) at a position thereon between the second vaporizer (84) to the ullage of the first tank (top of tank 2; “ liquid hydrogen taken out from the bottom of the tank 2 is vaporized by the vaporizer 84 and the vaporized liquid hydrogen (hydrogen gas) is supplied to the upper part of the tank 2”, page 6) .
It would have been obvious to a person having ordinary skills in the art before the effective filing date of the claimed invention to provide Boucher in view of Brady with Tanaka's structure discussed above and connect a duct downstream from the vaporizer to direct gaseous fuel to the tank , in order to pressurize tank 2 as described on page 6. providing the structure where “hydrogen is supplied to a use point in a high-pressure gas state” by “increasing the pressure of liquid hydrogen while being liquid and then evaporating There is […] is advantageous in that it can reduce energy consumption (page 2). Regarding the limitation “between the second vaporizer and the auxiliary power unit”, it would have been obvious to connect the duct, as discussed above, downstream from a vaporizer as taught by Tanaka (because Tanaka uses hydrogen gas), in this case taking advantage of vaporizers already in the system, and it would also be obvious to connect the duct upstream from the auxiliary power unit in order to access hydrogen gas that is not used as fuel in the auxiliary power unit and can increase the pressure in the tanks, as taught by Tanaka. The ullage also gives the fuel an expansion area to prevent dangerous conditions.
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Regarding claim 2, Boucher in view of Brady and Tanaka teaches the invention as discussed for claim 1. Bocher further teaches:
wherein the auxiliary power unit is arranged to generate electrical power (the auxiliary power unit 450 may be a fuel cell APU [0052], and fuel cells produce electrical power)
Regarding claim 6, Boucher in view of Brady and Tanaka teaches the invention as discussed for claim 2. Boucher teaches:
wherein the auxiliary power unit comprises a hydrogen-fuelled fuel cell stack comprising at least one fuel cell (“The auxiliary power unit 450 may be a fuel cell APU (as shown) or as a Brayton cycle system (e.g., combustion with a turbine). The fuel may then be used as a reactant in a fuel cell APU configuration or a combustion fuel for a Brayton cycle system, as will be appreciated by those of skill in the art. In the illustrative fuel cell APU configuration” [0052]; Fig. 4).
Regarding claim 11, Boucher in view of Brady and Tanaka teaches the invention as discussed for claim 1. Boucher in view of Brady and Tanaka, as discussed so far, is silent about:
further comprising a fourth fuel line arranged to convey the gaseous hydrogen from the second tank to the auxiliary power unit.
However, Tanaka teaches:
further comprising a fourth fuel line (44) arranged to convey the gaseous hydrogen from the second tank to the auxiliary power unit (use point 3, Fig. 1, and Tanaka teaches that the use point can be a gas turbine engine on page 2, and it is know in the art that gas turbine engines can be used as auxiliary power unit)
Regarding claim 12, Boucher in view of Brady and Tanaka teaches the invention as discussed for claim 1. Boucher in view of Brady and Tanaka, as discussed so far, is silent about:
wherein the apparatus is arranged to maintain an inert atmosphere within a volume which includes at least one of
(a) a portion of the first fuel line (inter alia, 210) including the first vaporizer (344); and
(b) a portion of the second fuel line including the second vaporizer (221).
However, Brady further teaches:
wherein the apparatus (inter alia, 312, 310, 314, 306, 304) is arranged to maintain an inert atmosphere (“to remove the residual substances from the fuel circuit as well as any leftover hydrogen that could present a risk of combustion flashback or flame holding to the fuel circuit, the fuel circuit transports an inert gas (e.g., nitrogen, helium, etc.) therethrough to purge the fuel circuit of non-inert substances” Col 4 ll. 59-66) within a volume which includes at least one of
a portion of the first fuel line (inter alia, 210) including the first vaporizer (344).
Regarding claim 13, Boucher in view of Brady and Tanaka teaches the invention as discussed for claim 12. Boucher in view of Brady and Tanaka as discussed so far, is silent about a nitrogen storage tank as claimed.
However, Brady teaches:
wherein the apparatus (inter alia, 312, 310, 314, 306, 304) comprises a duct coupling the nitrogen-storage tank to the volume (image below shows the duct connecting to the volume discussed earlier).
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Regarding claim 17, Boucher in view of Brady and Tanaka teaches the invention as discussed for claim 1. Boucher further teaches:
wherein the first vaporiser comprises a heat-exchanger arranged to transmit heat from oil within an oil system of the gas turbine engine to liquid hydrogen within the first fuel line (the fuel may pass through an optional heat exchanger 446, similar to the additional heat exchangers described above (e.g., powered electronics, ECS, cooled cooling air, engine oil, etc.) [0051]).
Regarding claim 18, Boucher in view of Brady and Tanaka teaches the invention as discussed for claim 1. Boucher further teaches:
wherein the first vaporiser comprises a heat-exchanger (432) arranged to transmit heat from an exhaust flow of the gas turbine engine to liquid hydrogen within the first fuel line (heat exchanger 432 is arranged in the core flow path C downstream of the combustor 412 [0051]; exhaust is on the right side of Fig. 4).
Regarding claim 19, Boucher in view of Brady and Tanaka teaches the invention as discussed for claim 1. Boucher further teaches:.
An aircraft comprising the propulsion system according to claim 1 (aircraft engine [0034]).
Regarding claim 20, Boucher in view of Brady and Tanaka teaches the invention as discussed for claim 19. Boucher further teaches:
The aircraft according to claim 19 wherein the aircraft is an aeroplane (commercial and military aircraft [0002] and “high-bypass geared aircraft engine” [0034], which is used in airplanes) or a helicopter.
Regarding claim 21, Boucher in view of Brady and Tanaka teaches the invention as discussed for claim 1. Boucher in view of Brady and Tanaka, as discussed so far, is silent about:
wherein the third fuel line and the apparatus constitute two separate paths by which the gaseous hydrogen can be conveyed from the second tank to the first fuel line.
However, Brady teaches:
wherein the third fuel line (image below) and the apparatus (image below) constitute two separate paths by which the gaseous hydrogen can be conveyed from the second tank to the first fuel line (one path via the lines downstream of 318, another path via the line downstream of 316, Fig. 3).
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Regarding claim 22, Boucher in view of Brady and Tanaka teaches the invention as discussed for claim 21. Boucher in view of Brady and Tanaka, as discussed so far, is silent about:
wherein the apparatus includes a duct (duct is the line above 316 in Fig. 3) that conveys both the gaseous nitrogen from the nitrogen storage tank and the gaseous hydrogen from the second tank to the first fuel line (or the second fuel line.
However, Brady teaches:
wherein the apparatus includes a duct (duct is the line above 316 in Fig. 3) that conveys both the gaseous nitrogen from the nitrogen storage tank (306) and the gaseous hydrogen from the second tank (304) to the first fuel line (image below)
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Claim(s) 3-4 is/are rejected under 35 U.S.C. 103 as being unpatentable over Boucher 20210340908 in view of Brady 11946417, Tanaka WO 2016047109 and Moore 20230184130
Regarding claim 3, Boucher in view of Brady and Tanaka teaches the invention as discussed for claim 2. Boucher in view of Brady and Tanaka, as discussed so far, is silent about and the second fuel pump being an electric fuel pump powered by the auxiliary power unit, as claimed.
However, Moore teaches and aircraft power and propulsion system, and:
wherein at least one of the first fuel pump and second fuel pump (115, [0068]) is an electric fuel pump (“electrically-powered fuel pump 115” [0068]), and the auxiliary power unit (200) is arranged to provide electrical power to the at least one electric fuel pump (one or more electric machines (not shown) driven by the APU 200 [0070-0073]).
It would have been obvious to a person having ordinary skills in the art before the effective filing date of the claimed invention to provide Boucher in view of Brady and Tanaka with Moore's structure discussed above in order to provide a system where “one or more electric machines (not shown) driven by the APU 200 are used as an electrical power source“ ([0071]), thus providing power to operate the pumps. Furthermore, the use of electric fuel pumps is recognized as ”Obvious to try” because there is a finite number of options to provide power for fuel pumps, electrical power being one of them, and one of ordinary skill in the art would have pursued this as a potential option.
Regarding claim 4, Boucher in view of Brady and Tanaka teaches the invention as discussed for claim 2. Boucher in view of Brady and Tanaka, as discussed so far, is silent about the electric starter-motor, as claimed.
However, Moore teaches:
wherein the gas turbine engine (Title) comprises an electric starter-motor (Each of the machines 111, 112 is operable as both a motor and as a generator [0059]’ “ power one or more of the electric machines 111, 112 as part of an electric start procedure” [0070]), and the auxiliary power unit is arranged to provide electrical power to the electric starter-motor (Fig. 4, [0071]).
It would have been obvious to a person having ordinary skills in the art before the effective filing date of the claimed invention to provide Boucher in view of Brady and Tanaka with Moore's structure discussed above in order to provide a system where “one or more electric machines (not shown) driven by the APU 200 are used as an electrical power source to replace or supplement the power provided by the ESS 130“ ([0071]), and provide “the spool-coupled electric machines 111, 112 in order to manage the surge margin of engine, especially during engine transients such as accelerations and decelerations” [0070], and providing a system for restarting a propulsive gas turbine engine during flight [0002].
Claim(s) 5, 7 is/are rejected under 35 U.S.C. 103 as being unpatentable over Boucher 20210340908 in view of Brady 11946417, Tanaka WO 2016047109 and Smith 20230045911 (Smith’911):
Regarding claim 5, Boucher in view of Brady and Tanaka teaches the invention as discussed for claim 2. Boucher in view of Brady and Tanaka, as discussed so far, is silent about the electric heater powered by the auxiliary power unit, as claimed.
However, Smith’911 teaches “a hydrogen fuel system for aircraft” (abstract) and:
wherein the second vaporiser comprises an electric heater, and the auxiliary power unit is arranged to provide electrical power to the electric heater (“the heating the flow of liquid hydrogen includes exchanging heat between an upstream working fluid in thermal communication with the upstream heat source and the flow of liquid hydrogen in the evaporator. In embodiments, the method includes powering the upstream heat source with at least one of an auxiliary power unit, an electric generator, and/or an electric energy module”[0014, 0005]).
It would have been obvious to a person having ordinary skills in the art before the effective filing date of the claimed invention to provide Boucher in view of Brady and Tanaka with Smith’911's structure discussed above because “Hydrogen is often stored cryogenically in order to maximize its energy density per unit volume, however it must first be evaporated to a gaseous state before use in combustion” [0002]. It is well established in the art that electric heat exchangers provide a controllable heat exchanger under conditions when other mediums may be cold (i.e., engine/system start).
Regarding claim 7, Boucher in view of Brady and Tanaka teaches the invention as discussed for claim 2. Boucher teaches:
wherein the auxiliary power unit comprises (i) an auxiliary hydrogen-burning gas turbine engine (“The auxiliary power unit 450 may be a fuel cell APU (as shown) or as a Brayton cycle system (e.g., combustion with a turbine). The fuel may then be used as a reactant in a fuel cell APU configuration or a combustion fuel for a Brayton cycle system, as will be appreciated by those of skill in the art” [0052]; Fig. 4).
Boucher in view of Brady and Tanaka teaches the APU as a gas turbine engine, but does not explicitly mention an electric generator as claimed, although this combination is known in the art.
However, Smith’911 teaches “a hydrogen fuel system for aircraft” (abstract) and:
(ii) an electrical generator arranged to be driven by the auxiliary hydrogen-burning gas turbine engine (“an auxiliary power unit 250, an electric generator 252” [0034, 0073]).
It would have been obvious to a person having ordinary skills in the art before the effective filing date of the claimed invention to provide Boucher in view of Brady and Tanaka with Smith’911's structure discussed above in order to provide an “electric energy source is external to the gas turbine engine, and wherein the electric energy source includes at least one of: an auxiliary power unit (250), an electric generator (252)” [0073], as taught by Smith’911
Claim(s) 8 is/are rejected under 35 U.S.C. 103 as being unpatentable over Boucher 20210340908 in view of Brady 11946417, Tanaka WO 2016047109 and Kami 20020092562 and Hobbs 20050000802
Regarding claim 8, Boucher in view of Brady and Tanaka teaches the invention as discussed for claim 2. Boucher in view of Brady and Tanaka is silent about tank, fuel lines and vaporizer being contained as claimed
However, Kami teaches:
wherein the first tank (40, Fig. 2) and respective portions of the fuel lines are contained within a volume which is arranged for evacuation during operation of the propulsion system (“gas filling pipe 44 is used to fill the tank 40 with gaseous fuel whilst the gas supply pipe is used to supply an engine (not shown) with gaseous fuel contained within the tank 40” [0034], teachings that fuel lines are contained within 30, Fig. 2).
It would have been obvious to a person having ordinary skills in the art before the effective filing date of the claimed invention to provide Boucher in view of Brady and Tanaka with Kami's teachings discussed above, such that the first tank and respective portions of the first fuel line and second fuel lines extending between the first tank and the first vaporiser and second vaporiser, respectively, are contained within a volume which is arranged for evacuation during operation of the propulsion system, as taught by Kami, in order to cover the components containing fuel, such that “If gaseous fuel leaks from within the tank, the structure is operated to discharge the gaseous fuel out of the vehicle” (Abstract, the modification adds a cover to the tank and first fuel line, vaporizer, which is able to be vented to open air), eliminating leaked fuel from the system to reduce exposure to critical components and reduce risk of fire etc.
Boucher in view of Brady, Tanaka and Kami teaches a containment system (Kami as discussed above), but Boucher in view of Brady, Tanaka and Kami, as discussed so far, is silent about the vacuum pump as claimed.
However, Hobbs teaches a hydrogen handling system where any leaking hydrogen, fires, or explosions may be contained and/or directed upward, protecting human life and property (abstract), and:
comprises vacuum pump (an exhaust fan may create a low pressure area or partial vacuum” [0108]) and substantially evacuate said volume (an exhaust fan may create a low pressure area or partial vacuum within enclosure 150 and may prevent gasses within enclosure 150 from leaking out through any openings in enclosure 150 [0108]).
It would have been obvious to a person having ordinary skills in the art before the effective filing date of the claimed invention to provide Boucher in view of Brady, Tanaka and Kami with Hobbs's structure discussed above in order to “create a low pressure area or partial vacuum within enclosure 150 and may prevent gasses within enclosure 150 from leaking out through any openings in enclosure 150” [0108]. Regarding the limitations “an electric vacuum pump” and “arranged to receive electrical power from the auxiliary power unit”, the use of an electric vacuum pump has been recognized as an “obvious to try” solution, because there is a finite number of options to provide power to pumps, electrical power being one of them, and one of ordinary skill in the art would have pursued this as a potential option.
Claim(s) 9 is/are rejected under 35 U.S.C. 103 as being unpatentable over Boucher 20210340908 in view of Brady 11946417, Tanaka WO 2016047109 and Kami 20020092562
Regarding claim 9, Boucher in view of Brady and Tanaka teaches the invention as discussed for claim 1. Boucher in view of Brady and Tanaka is silent about tank, fuel lines and vaporizer being contained as claimed.
However, Kami teaches:
wherein the first tank (40, Fig. 2) and respective portions of the fuel lines within a volume which is arranged for evacuation during operation of the propulsion system (“gas filling pipe 44 is used to fill the tank 40 with gaseous fuel whilst the gas supply pipe is used to supply an engine (not shown) with gaseous fuel contained within the tank 40” [0034], teachings that fuel lines are contained within 30, Fig. 2).
It would have been obvious to a person having ordinary skills in the art before the effective filing date of the claimed invention to provide Boucher in view of Brady and Tanaka with Kami's teachings discussed above, such that the first tank and respective portions of the first fuel line and second fuel lines extending between the first tank and the first vaporiser and second vaporiser, respectively, are contained within a volume which is arranged for evacuation during operation of the propulsion system, as taught by Kami, in order to cover the components containing fuel, such that “If gaseous fuel leaks from within the tank, the structure is operated to discharge the gaseous fuel out of the vehicle” (Abstract, the modification adds a cover to the tank and first fuel line, vaporizer, which is able to be vented to open air), eliminating leaked fuel from the system to reduce exposure to critical components and reduce risk of fire etc.
Claim(s) 15 is/are rejected under 35 U.S.C. 103 as being unpatentable over Boucher 20210340908 in view of Brady 11946417, Tanaka WO 2016047109 and Muldoon 20220381185
Regarding claim 15, Boucher in view of Brady and Tanaka teaches the invention as discussed for claim 12.
Boucher in view of Brady and Tanaka, as discussed so far, is silent about:
further comprising
a fourth fuel line arranged to convey the gaseous hydrogen from the second tank to the auxiliary power unit.
However, Muldoon teaches an “Aircraft hydrogen fuel systems and methods and systems of starting such systems are described” (abstract) and:
a fourth fuel line (image below) arranged to convey the gaseous hydrogen from the second tank (704) to the auxiliary power unit (706).
It would have been obvious to a person having ordinary skills in the art before the effective filing date of the claimed invention to provide Boucher in view of Brady and Tanaka with Muldoon's teachings discussed above because “Such configurations provide for a weight-efficient and volume-efficient means of supplying gaseous hydrogen into the engines to start the engines, and then a switch can be made to a liquid hydrogen fuel source when waste heat is available to convert the liquid hydrogen to gaseous hydrogen. Further, advantageously, embodiments of the present disclosure enable a redundancy of starting methods in the event of combustor flame-out” [0063]
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Claim(s) 16 is/are rejected under 35 U.S.C. 103 as being unpatentable over Boucher 20210340908 in view of Brady 11946417, Tanaka WO 2016047109 and Smith 20220381183 (Smith’183)
Regarding claim 16, Boucher in view of Brady and Tanaka teaches the invention as discussed for claim 1. Boucher in view of Brady and Tanaka, as discussed so far, is silent about:
wherein the first vaporiser comprises a heat-exchanger arranged to receive compressor bleed air from the gas turbine engine and transmit heat from the compressor bleed air to liquid hydrogen within the first fuel line
However, Smith’183 teaches:
wherein the first vaporiser comprises a heat-exchanger (122, Fig. 1) arranged to receive compressor bleed air (“The heat exchanger 122 is fluidly connected to the primary gas path 106 between the adjacent first and second stage compressors 140, 142 such that the inter-stage duct 144 forms a compressor air conduit through the heat exchanger 122” [0027]) from the gas turbine engine (Fig. 1) and transmit heat from the compressor bleed air to liquid hydrogen within the first fuel line (line from 131 to the gas turbine, Fig. 1).
It would have been obvious to one of ordinary skill in the art at the time of effective filing to provide Boucher in view of Brady and Tanaka with Smith’183’s teachings, to transmit heat from the compressor bleed air to liquid hydrogen within the first fuel line as taught by Smith because it has been held that applying a known technique, in this case Smith’s use of compressor bleed air according to the steps described immediately above, to a known device, in this case, Boucher in view of Brady and Tanaka’s propulsion system, ready for improvement to yield predictable results, in this case vaporizing hydrogen, was an obvious extension of prior art teachings, KSR, 550 U.S. 398 (2007), 82 USPQe2d at 1396; MPEP 2143(D) (The modification uses compressor bleed air to vaporizer hydrogen)
Response to Arguments/Remarks
Applicant’s arguments have been considered, but they are not persuasive because they do not apply to the new combination of references, i.e., adding a new reference to the old combination of references, that was necessitated by applicant’s amendment. However, to the extent possible, applicant’s arguments have been addressed in the body of the rejections above, at the appropriate location.
Applicant argues on page 9:
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Examiner’s response: Applicant’s arguments were carefully considered but the examiner respectfully disagrees. Tanaka teaches that heat exchangers create a scenario where “hydrogen is supplied to a use point in a high-pressure gas state” by “increasing the pressure of liquid hydrogen while being liquid and then evaporating There is […] is advantageous in that it can reduce energy consumption (page 2), as discussed in the rejection. One of ordinary skill would recognize that heat exchangers present in the system are capable of providing this benefit, and the use of one of the exchangers would be an obvious decision, and it would be an the engineer’s choice to select one of them for use; in this case, an APU is considered a less critical equipment than the gas turbine providing propulsion to the aircraft, so any added complexity to the propulsion system would be avoided if possible (to maintain reliability), making the APU portion of the system an obvious choice.
Correspondence
Any inquiry concerning this communication or earlier communications from the examiner should be directed to Roberto T. Igue whose telephone number is (303)297-4389. The examiner can normally be reached Monday-Friday 7:30-4:30 PT.
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, Phutthiwat Wongwian can be reached at (571) 270-5426. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/ROBERTO TOSHIHARU IGUE/Examiner, Art Unit 3741
/PHUTTHIWAT WONGWIAN/Supervisory Patent Examiner, Art Unit 3741
