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 .
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and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114.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 05/14/2026 has been entered.
Claims 21, 29-30, 36-38 and 41-47 are currently being examined.
Claim Objections
Claims 36 and 41 are objected to because of the following informalities:
Claim 36: “a portion of the flowline” in lines 22-23 should read as – the [[a]] portion of the flowline --.
Claim 41: “the first portion of the flowline” in line 3 should read as – a [[the]] first portion of the flowline --. Appropriate correction is required.
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) 21, 41 and 45 is/are rejected under 35 U.S.C. 103 as being unpatentable over Minelli et al. 20250198338 in view of Brady 20230358180.
Regarding independent claim 21, Minelli discloses, with reference to Fig. 7C, a system comprising:
a flowline (labeled in annotated Fig. 7C) including a trunk section (labeled in annotated Fig. 7C), a first branch section (labeled in annotated Fig. 7C) coupled to a first portion of the trunk section (labeled in annotated Fig. 7C), and a second branch section (labeled in annotated Fig. 7C) coupled to a third portion of the trunk section (labeled in annotated Fig. 7C) and a fourth portion of the trunk section (labeled in annotated Fig. 7C);
a fuel tank (50) coupled to a first end (labeled in annotated Fig. 7C) of the trunk section;
a combustor (16) of a gas turbine engine (Fig. 1) coupled to a second end (labeled in annotated Fig. 7C) of the trunk section, the flowline to carry fuel from the fuel tank to the combustor (intended use but flowline in Fig. 7C is for carrying fuel from 50 to 16 per [0417] which describes first embodiment of Fig. 6 with Fig. 7C having some similar components);
a trim heat exchanger coupled (1006) to the first branch section (1006 is coupled to first branch section), the fuel to absorb first heat in the trim heat exchanger as the fuel flows through the first branch section (first heat from oil is transferred to the fuel in 1006 per [0419]);
a waste heat recovery heat exchanger (7010 Fig. 7C) of the gas turbine engine (per para. 0427 7010 is turbine case cooling (TCC) systems which is part of the gas turbine engine), the waste heat recovery heat exchanger coupled to the trunk section of the flowline (7010 is coupled to trunk section of the flowline) (i) downstream of the first portion, the second portion, and the third portion of the trunk section (7010 is coupled downstream of first portion, second portion, and third portion of the trunk section) and (ii) upstream of the fourth portion of the trunk section (7010 is upstream of fourth portion of the trunk section), the fuel to absorb second heat in the waste heat recovery heat exchanger; and
a bypass valve (7011) coupled to the second branch section to control a flow rate of the fuel that flows from the third portion to the fourth portion of the trunk section, the bypass valve configured to cause a portion of the fuel to flow from the third portion to the fourth portion of the trunk section during first operations, wherein the valve is configured to block the fuel from flowing through the first branch section when the bypass valve causes the portion of the fuel to flow through the second branch section from the third portion to the fourth portion of the trunk section.
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Minelli does not explicitly disclose in Fig. 7C the first branch section coupled to a first portion of the trunk section and a second portion of the trunk section; a valve coupled to the first branch section to control a flow rate of the fuel in the first branch section; the waste heat recovery heat exchanger positioned in an exhaust section of the gas turbine engine, the fuel to absorb second heat in the waste heat recovery heat exchanger from core exhaust waste heat.
Minelli further teaches in Fig. 6 a first branch section coupled to a first portion of the trunk section and a second portion of the trunk section and a valve coupled to the first branch section to control a flow rate of the fuel in the first branch section (per [0420] and as shown in Fig. 6, a fuel bypass pipe 1005, i.e., second portion of trunk section in annotated Fig. 6, allows some of the fuel to avoid passing through trim heat exchanger 1006 and a valve although not shown may determine what proportion of the fuel passes through a first portion of the flowline through trim heat exchanger 1006 and what proportion passes through bypass pipe 1005; the valve is necessarily coupled to the flowline to determine proportion of fuel flow; also per [0503] one or more bypass pipes such as shown in Fig. 6 may be provided in various implementations). Controlling the fuel flow by recirculation through and/or bypassing of one or more heat exchangers can assist in heat management such as influencing fuel temperature on entry to the combustor 16 or pump 1003, or amount of heat transferred to the fuel per [0425]. The system of Fig. 7C may be modified to have a valve and bypass pipe coupled to the flowline to allow some fuel to bypass and not flow through trim heat exchanger 1006.
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It would have been obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to modify the system of Fig. 7C of Minelli to include the first branch section coupled to a first portion of the trunk section and a second portion of the trunk section; a valve coupled to the first branch section to control a flow rate of the fuel in the first branch section as further taught by Minelli to enable via the valve to control proportioning a flow of fuel through the first branch section and the trim heat exchanger and enable via the valve proportioning a flow of fuel through the second portion of the trunk section to avoid passing through the trim heat exchanger to assist in heat management such as influencing fuel temperature on entry to the combustor or fuel pump, or amount of heat transferred to the fuel.
As modified, Minelli does not explicitly teach the waste heat recovery heat exchanger positioned in an exhaust section of the gas turbine engine, the fuel to absorb second heat in the waste heat recovery heat exchanger from core exhaust waste heat.
Brady teaches with reference to Figs. 2-3, a gas turbine engine (100) with a waste heat recovery heat exchanger (labeled in annotated Fig. 3) positioned in an exhaust section (128 Fig. 3) of the gas turbine engine (waste heat recovery heat exchanger is positioned in exhaust section 128 in annotated Fig. 3), a fuel to absorb heat in the waste heat recovery heat exchanger from core exhaust waste heat ([0053] describes conduit(s) 302 carrying fuel can be positioned in the outer casing 118 in FIG. 2 of the gas turbine 100 and can form loops that are positioned at least partially around a perimeter of the exhaust section 128 that enables the thermal energy from the combustion gases 160, i.e., core exhaust waste heat, to heat the fuel in preparation for combustion, i.e., the fuel absorbs heat in the waste heat recovery heat exchanger).
Minelli modified in view of Brady has waste heat recovery heat exchanger 7010 include loops carrying fuel that are positioned at least partially around a perimeter of the exhaust section in the outer casing of the exhaust section such that the outer casing, i.e., turbine case, is cooled by the fuel while the fuel absorbs second heat transferred from the core exhaust waste heat via the turbine case cooling system components in the exhaust section.
It would have been obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to modify the invention of Minelli such that the waste heat recovery heat exchanger is positioned in an exhaust section of the gas turbine engine, the fuel to absorb the second heat in the waste heat recovery heat exchanger from core exhaust waste heat as taught by Brady to cool the outer casing of the exhaust section while heating the fuel in preparation for combustion.
Regarding claim 41, Minelli in view of Brady teaches all that is claimed above and Minelli further teaches the system includes fuel temperature controlling circuitry ([0506] describes controller 58 is used to actively manage fuel and/or oil flows through and around the heat exchangers 1004, 1006, 2020 and controller 58 may be a part of, or provided by, an EEC, or may be a separate unit; 58 may receive inputs from one or more temperature sensors 1009, and may control one or more valves, and/or the pump 1003, based on the received data and one or more oil feed pumps and/or scavenge pumps may also be controlled by the controller) configured to:
cause the valve to block the fuel from flowing through the first portion of the flowline and absorbing the first heat in the trim heat exchanger during first operations (during first engine operations when 58 receives temperature sensor data per [0506] indicating less heating of the fuel is needed or desired, per [0507] fuel flow may be controlled by using one or more bypass pipes 1005 arranged to allow a proportion of the fuel to avoid passing through either or both heat exchangers, such that the valve as controlled by controller 58 is caused to bypass and therefore block the fuel from flowing through the first branch section, i.e., a first portion of the flowline, and absorbing the first heat in trim heat exchanger 1006);
cause the valve to enable the fuel to flow through the first portion of the flowline and absorb the first heat in the trim heat exchanger during second operations different than the first operations (during second engine operations when controller 58 receives temperature sensor data per [0506] indicating more heating of the fuel is needed or desired, 58 controls the valve to enable the fuel to flow through the first portion of the flowline to trim heat exchanger 1006 in which the fuel absorbs the first heat);
cause the bypass valve to block the fuel from bypassing the waste heat recovery heat exchanger during the second operations (during second engine operations when 58 receives temperature sensor data per [0506] indicating more heating of the fuel is needed or desired and 58 determines fuel is needed for waste heat recovery heat exchanger 7010 and fuel is not needed to bypass 7010 to be returned straight to the main fuel flow path/combustor 16, 58 causes bypass valve 7011 to control the proportions of fuel accordingly such that 7011 blocks the fuel from bypassing 7010); and
cause the bypass valve to enable the fuel to bypass the waste heat recovery heat exchanger during the first operations (during first engine operations when 58 receives temperature sensor data per [0506] indicating less heating of the fuel is needed, 58 causes bypass valve 7011 to enable some of the fuel to bypass 7010 to be returned straight to combustor 16, as per [0428] any fuel not needed for waste heat recovery heat exchanger 7010 may be returned straight to the main fuel flow path/combustor 16).
Regarding claim 45, Minelli in view of Brady teaches all that is claimed above and Minelli further teaches including fuel temperature controlling circuitry ([0506] describes controller 58 is used to actively manage fuel and/or oil flows through and around the heat exchangers 1004, 1006, 2020 and controller 58 may be a part of, or provided by, an EEC, or may be a separate unit; 58 may receive inputs from one or more temperature sensors 1009, and may control one or more valves, and/or the pump 1003, based on the received data and one or more oil feed pumps and/or scavenge pumps may also be controlled by the controller) configured to:
cause the valve to prevent the fuel from flowing through the first branch section during the first operations (during first engine operations when 58 receives temperature sensor data per [0506] indicating less heating of the fuel is needed or desired, per [0507] fuel flow may be controlled by using one or more bypass pipes 1005 arranged to allow a proportion of the fuel to avoid passing through either or both heat exchangers, such that controller 58 causes valve to bypass the fuel and therefore prevent the fuel from flowing through the first branch section and trim heat exchanger 1006); and
cause the bypass valve to prevent the fuel from flowing through the second branch section during second operations (during second engine operations when 58 receives temperature sensor data per [0506] indicating more heating of the fuel is needed or desired and 58 determines fuel is needed for waste heat recovery heat exchanger 7010 and fuel is not needed to bypass 7010 via the second branch section to be returned straight to the main fuel flow path/combustor 16, 58 causes bypass valve 7011 to control the proportions of fuel accordingly such that 7011 blocks the fuel from flowing through the second branch section and bypassing 7010), wherein the valve enables the fuel to flow through the first branch section during the second operations (during second engine operations when controller 58 receives temperature sensor data per [0506] indicating more heating of the fuel is needed or desired, 58 controls the valve to enable the fuel to flow through the first branch section to trim heat exchanger 1006 in which the fuel absorbs heat).
Claim(s) 29-30, 36-38, 44 and 46-47 is/are rejected under 35 U.S.C. 103 as being unpatentable over Minelli et al. 20250198338.
Regarding independent claim 29, Minelli discloses a system comprising:
a flowline (labeled in annotated Fig. 7C);
a fuel tank (50 Fig. 7C; para. 0428) coupled to a first end (labeled in annotated Fig. 7C) of the flowline;
a combustor (16 Fig. 7C; para. 0428) coupled to a second end (labeled in annotated Fig. 7C) of the flowline, the flowline to carry fuel from the fuel tank to the combustor (intended use but flowline in Fig. 7C is for carrying fuel from 50 to 16 per para. 0417 which describes first embodiment of Fig. 6 with Fig. 7C having some similar components);
a trim heat exchanger (1006 Fig. 7C) coupled to a first portion of the flowline (labeled in annotated Fig. 7C; 1006 is coupled to first portion of flowline), the fuel to absorb first heat in the trim heat exchanger (first heat from oil is transferred to the fuel in 1006 per para. 0419);
a waste heat recovery heat exchanger (7010 Fig. 7C) coupled to a second portion of the flowline (labeled in annotated Fig. 7C; 7010 is coupled to second portion of flowline), the fuel to absorb second heat in the waste heat recovery heat exchanger (per para. 0427, 7010 may include turbine case cooling (TCC) systems in which the fuel absorbs second heat from turbine case cooling system components, such that 7010 recovers waste heat from the turbine case cooling system components by transferring the second heat to the fuel); and
a bypass valve (7011 Fig. 7C) coupled to a third portion of the flowline (labeled in annotated Fig. 7C) upstream of the waste heat recovery heat exchanger (third portion of flowline is upstream of 7010 in annotated Fig. 7C with respect to fuel flow direction towards combustor 16 as shown by flow arrows) to control a flow rate of the fuel that bypasses the waste heat recovery heat exchanger (per para. 0428, at least a portion of the fuel exiting heat exchanger 1004 may be returned to the main fuel flowline without passing through waste heat recovery heat exchanger 7010—the proportion directed to 7010 may be controlled with bypass valve 7011), the bypass valve to cause a portion of the second heat to be absorbed from the fuel (this limitation is intended use but bypass valve 7011 is capable of this intended use since 7011 may send a proportion of fuel to the waste heat recovery heat exchanger 7010 and may bypass another proportion of fuel, the fuel having second heat subsequently flowing from waste heat recovery heat exchanger 7010 and re-joining with fuel which has bypassed 7010 and therefore has not been further heated in 7010, such that the bypassed fuel absorbs a portion of the second heat from the fuel coming from 7010).
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Minelli does not explicitly teach in Fig. 7C a valve coupled to the flowline to control a flow rate of the fuel in the first portion of the flowline, and
wherein the valve blocks the fuel from entering the first portion of the flowline when the bypass valve causes the portion of the second heat to be absorbed from the fuel. (Limitations in italics are intended use.)
Minelli further teaches in Fig. 6 a valve coupled to a flowline to control a flow rate of the fuel in a first portion of the flowline (per [0420] and as shown in Fig. 6, a fuel bypass pipe 1005 allows some of the fuel to avoid passing through trim heat exchanger 1006 and a valve although not shown may determine what proportion of the fuel passes through a first portion of the flowline through trim heat exchanger 1006 and what proportion passes through bypass pipe 1005; the valve is necessarily coupled to the flowline to determine proportion of fuel flow; also per [0503] one or more bypass pipes such as shown in Fig. 6 may be provided in various implementations). Controlling the fuel flow by bypassing of one or more heat exchangers can assist in heat management such as influencing fuel temperature on entry to the combustor 16 or pump 1003, or amount of heat transferred to the fuel per [0425]. The system of Fig. 7C may be modified to have a valve and bypass pipe coupled to the flowline to allow fuel to bypass and not flow through first trim heat exchanger 1006.
It would have been obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to modify the system of Fig. 7C of Minelli to include a valve coupled to the flowline to control a flow rate of the fuel in the first portion of the flowline as further taught by Minelli to enable via the valve proportioning a flow of fuel through the first portion of the flowline and the trim heat exchanger and enable via the valve proportioning a flow of fuel through the bypass pipe to avoid passing through the trim heat exchanger to assist in heat management such as influencing fuel temperature on entry to the combustor or fuel pump, or amount of heat transferred to the fuel.
In addition, as modified, the invention of Minelli is capable of having the valve block the fuel from entering the first portion of the flowline when the bypass valve causes the portion of the second heat to be absorbed from the fuel as claimed, since the position of the valve and the position of the bypass valve are each controllable such that the valve may be positioned to bypass flow and block fuel from entering the first portion of the flowline at the same time as the bypass valve is positioned to have some fuel bypass the waste heat recovery heat exchanger and cause the portion of the second heat to be absorbed from the fuel.
Regarding claim 30, Minelli further teaches the first trim heat exchanger is positioned upstream of the waste heat recovery heat exchanger (1006 is upstream of 7010 in Fig. 7C).
Regarding independent claim 36, Minelli teaches a system comprising:
a flowline (labeled in annotated Fig. 7C);
a fuel tank (50 Fig. 7C; para. 0428) coupled to a first end (labeled in annotated Fig. 7C) of the flowline;
a combustor (16 Fig. 7C; para. 0428) coupled to a second end (labeled in annotated Fig. 7C) of the flowline, the flowline to carry fuel from the fuel tank to the combustor (intended use but flowline in Fig. 7C is for carrying fuel from 50 to 16 per para. 0417 which describes first embodiment of Fig. 6 with Fig. 7C having some similar components);
a trim heat exchanger (1006 Fig. 7C) coupled to the flowline (1006 is coupled to the flowline in annotated Fig. 7C), the fuel to absorb first heat in the trim heat exchanger (first heat from oil is transferred to the fuel in 1006 per para. 0419);
a waste heat recovery heat exchanger (7010 Fig. 7C) coupled to the flowline (7010 is coupled to the flowline in Fig. 7C), the fuel to absorb second heat in the waste heat recovery heat exchanger (per para. 0427, 7010 may include turbine case cooling (TCC) systems in which the fuel absorbs second heat from turbine case cooling system components, such that 7010 recovers waste heat from the turbine case cooling system components by transferring the second heat to the fuel);
a second valve (7011 Fig. 7C) coupled to the flowline, wherein a position of the second valve controls whether the second heat is partially absorbed from the fuel (per para. 0428, at least a portion of the fuel exiting heat exchanger 1004 may be returned to the main fuel flowline without passing through waste heat recovery heat exchanger 7010 and the proportion directed to 7010 may be adjusted based on need and controlled with second valve 7011; a position of the second valve 7011 may send a proportion of fuel to the waste heat recovery heat exchanger 7010 and may bypass another proportion of fuel, the proportion of fuel having second heat subsequently flowing from waste heat recovery heat exchanger 7010 re-joins with the proportion of fuel which has bypassed 7010 and therefore has not been further heated in 7010, such that the bypassed fuel absorbs a portion of the second heat from the proportion of fuel coming from 7010),
wherein at least a first portion of the fuel flows to the waste heat recovery heat exchanger throughout first engine operations and second engine operations (per [0428] the proportion of fuel directed to 7010 may be adjusted based on need and controlled by second valve 7011, such that at least a first portion of the fuel flows to 7010 throughout first engine operations and second engine operations); and
fuel temperature controlling circuitry ([0506] describes controller 58 is used to actively manage fuel and/or oil flows through and around the heat exchangers 1004, 1006, 2020 and controller 58 may be a part of, or provided by, an EEC, or may be a separate unit; 58 may receive inputs from one or more temperature sensors 1009, and may control one or more valves, and/or the pump 1003, based on the received data and one or more oil feed pumps and/or scavenge pumps may also be controlled by the controller) configured to:
wherein the second valve causes a second portion of the fuel to flow through a portion of the flowline (labeled in annotated Fig. 7C) that causes the second heat to be partially absorbed from the at least the first portion of the fuel during the first engine operations (during first engine operations when 58 receives temperature sensor data per [0506] indicating less heating of the fuel is needed or desired and per [0428], at least a portion of the fuel exiting heat exchanger 1004 may be returned to the main fuel flowline without passing through waste heat recovery heat exchanger 7010—the proportion directed to 7010 may be adjusted based on need and controlled with bypass valve 7011 and any fuel not needed for waste heat recovery heat exchanger 7010 may be returned straight to the main fuel flow path/combustor 16, 58 controls second valve 7011 to control the proportions of fuel accordingly to cause a second portion of the fuel to bypass 7010 to flow through a portion of the flowline and then rejoin with the at least the first portion of the fuel which has passed through 7010 absorbing second heat, where the mixing of the relatively cooler second portion of the fuel with the at least the first portion of the fuel causes the second heat to be partially absorbed from the at least the first portion of the fuel by the second portion of the fuel); and
cause the second valve to block the second portion of the fuel from flowing to a portion of the flowline where, if unblocked, flow would otherwise cause the second heat to be partially absorbed from the at least the first portion of the fuel during the second engine operations (during second engine operations, when 58 receives temperature sensor data per [0506] indicating more heating of the fuel is needed or desired and 58 determines fuel is needed for waste heat recovery heat exchanger 7010 and is not needed to bypass 7010 and be returned straight to the main fuel flow path/combustor 16, 58 causes second valve 7011 to control the proportions of fuel accordingly to block the second portion of the fuel from bypassing 7010 and flowing to a portion of the flowline where, if unblocked, flow would otherwise cause the second heat to be partially absorbed from the at least the first portion of the fuel as discussed above when cooler bypassed fuel mixes with the at least the first portion of the fuel).
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Minelli does not explicitly teach in Fig. 7C a first valve coupled to the flowline, wherein a position of the first valve controls whether the fuel absorbs the first heat in the trim heat exchanger; the fuel temperature controlling circuitry configured to: cause the first valve to block the second portion of the fuel from flowing to the trim heat exchanger during the first engine operations; and wherein the first valve causes the second portion of the fuel to flow to the trim heat exchanger during the second engine operations.
Minelli further teaches in Fig. 6 a first valve coupled to the flowline (per [0420] and as shown in Fig. 6, a fuel bypass pipe 1005 allows some of the fuel to avoid passing through trim heat exchanger 1006 and a valve although not shown may determine what proportion of the fuel passes through a first portion of the flowline through trim heat exchanger 1006 and what proportion passes through bypass pipe 1005; the valve is necessarily coupled to the flowline to determine proportion of fuel flow; also per [0503] one or more bypass pipes such as shown in Fig. 6 may be provided in various implementations), wherein a position of the first valve controls whether the fuel absorbs the first heat in the trim heat exchanger (per [0420] first valve determines what proportion of the fuel passes through trim heat exchanger 1006 and accordingly absorbs first heat and first valve determines what proportion passes through bypass pipe 1005).
Controlling the fuel flow by bypassing of one or more heat exchangers can assist in heat management such as influencing fuel temperature on entry to the combustor 16 or pump 1003, or amount of heat transferred to the fuel per [0425]. The system of Fig. 7C may be modified to have a first valve and bypass pipe coupled to the flowline to allow some fuel to bypass and not flow through trim heat exchanger 1006.
It would have been obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to modify the system of Fig. 7C of Minelli to include a first valve coupled to the flowline, wherein a position of the first valve controls whether the fuel absorbs the first heat in the trim heat exchanger as further taught by Minelli to enable via the valve proportioning a flow of fuel through the first trim heat exchanger and enable via the first valve proportioning a flow of fuel through the bypass pipe to avoid passing through the trim heat exchanger to assist in heat management such as influencing fuel temperature on entry to the combustor or fuel pump, or amount of heat transferred to the fuel.
As modified, Minelli further teaches
the fuel temperature controlling circuitry configured to:
cause the first valve to block a second portion of the fuel from flowing to the trim heat exchanger during the first engine operations (during first engine operations when 58 receives temperature sensor data per [0506] indicating less heating of the fuel is needed or desired and per [0507] fuel flow may be controlled by using bypass pipe 1005 arranged to allow the fuel to avoid passing through trim heat exchanger 1006, i.e., first valve is caused to block the second portion of the fuel from flowing to trim heat exchanger 1006 and to bypass the second portion of fuel via bypass pipe 1005), wherein the second valve causes the second portion of the fuel to flow through a portion of the flowline that causes the second heat to be partially absorbed from the at least the first portion of the fuel during the first engine operations (see above); and
cause the second valve to block the second portion of the fuel from flowing to a portion of the flowline where, if unblocked, flow would otherwise cause the second heat to be partially absorbed from the at least the first portion of the fuel during the second engine operations (see above), wherein the first valve causes the second portion of the fuel to flow to the trim heat exchanger during the second engine operations (during second engine operations when controller 58 receives temperature sensor data per [0506] indicating more heating of the fuel is needed or desired, 58 controls the first valve to cause the second portion of the fuel to flow to trim heat exchanger 1006 in which the fuel absorbs the first heat).
Regarding claim 37, Minelli further teaches the second valve is coupled to a branch section (labeled in annotated Fig. 7C; branch section is coupled to second valve 7011 in annotated Fig. 7C) of the flowline that enables a portion of the fuel to bypass the waste heat recovery heat exchanger (a portion of fuel flowing from bypass valve 7011 is able to bypass 7010 via branch section in annotated Fig. 7C).
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Regarding claim 38, Minelli further teaches further including a mixer to mix the second portion of the fuel that bypasses the waste heat recovery heat exchanger with the at least the first portion of the fuel that passed through the waste heat recovery (mixer is labeled in annotated Fig. 7C at junction of branch section with section extending from 7010 to 16; at least para. 0030 describes fuel from one branch re-joining, i.e., mixing with, fuel from another branch or path; the at least first portion of fuel that passed through 7010 mixes at the mixer with the second portion of fuel that bypassed 7010 via the branch section).
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Regarding claim 44, Minelli teaches the fuel temperature controlling circuitry is configured to cause the second valve to block the fuel from bypassing the waste heat recovery heat exchanger during the second engine operations (as discussed above in claim 36, during second engine operations when 58 receives temperature sensor data per [0506] indicating more heating of the fuel is needed or desired and 58 determines fuel is needed for waste heat recovery heat exchanger 7010 and fuel is not needed to bypass 7010 to be returned straight to the main fuel flow path/combustor 16, 58 causes second valve 7011 to block the fuel from bypassing 7010).
Regarding claim 46, Minelli further teaches including fuel temperature control circuitry ([0506] describes controller 58 is used to actively manage fuel and/or oil flows through and around the heat exchangers 1004, 1006, 2020 and controller 58 may be a part of, or provided by, an EEC, or may be a separate unit; 58 may receive inputs from one or more temperature sensors 1009, and may control one or more valves, and/or the pump 1003, based on the received data and one or more oil feed pumps and/or scavenge pumps may also be controlled by the controller) configured to cause the bypass valve to prevent the portion of the fuel from bypassing the waste heat recovery heat exchanger when a position of the valve enables the fuel to flow to the trim heat exchanger (when 58 receives temperature sensor data per [0506] indicating more heating of the fuel is needed or desired and 58 determines fuel is needed for waste heat recovery heat exchanger 7010 and is not needed to bypass 7010 and be returned straight to the main fuel flow path/combustor 16, 58 causes bypass valve 7011 to control the proportions of fuel accordingly to prevent the portion of the fuel from bypassing 7010 and 58 also positions the valve to enable the fuel to flow to trim heat exchanger 1006 so the fuel absorbs heat).
Regarding claim 47, Minelli further teaches wherein the fuel temperature controlling circuitry is configured to:
cause the first valve to prevent the fuel from flowing to the trim heat exchanger during the first engine operations (during first engine operations when 58 receives temperature sensor data per [0506] indicating less heating of the fuel is needed or desired and per [0507] fuel flow may be controlled by using bypass pipe 1005 arranged to allow the fuel to avoid passing through trim heat exchanger 1006, i.e., first valve is caused to prevent the fuel from flowing to trim heat exchanger 1006 and to bypass the second portion of fuel via bypass pipe 1005); and
cause the second valve to prevent the fuel from flowing to the portion of the flowline where flow would otherwise cause the second heat to be partially absorbed from the fuel during the second engine operations (during second engine operations, when 58 receives temperature sensor data per [0506] indicating more heating of the fuel is needed or desired and 58 determines fuel is needed for waste heat recovery heat exchanger 7010 and is not needed to bypass 7010 and be returned straight to the main fuel flow path/combustor 16, 58 causes second valve 7011 to control the proportions of fuel accordingly to prevent the fuel from bypassing 7010 and flowing to the portion of the flowline where flow would otherwise cause the second heat to be partially absorbed from the at least the first portion of the fuel as discussed above when cooler bypassed fuel mixes with the at least the first portion of the fuel).
Claim(s) 42-43 is/are rejected under 35 U.S.C. 103 as being unpatentable over Minelli et al. 20250198338 in view of Brady 20230358180.
Regarding claims 42 and 43, Minelli teaches all that is claimed above respectively in claims 29 and 36, and further teaches the system includes a gas turbine engine (Fig. 1) including the combustor 16, a turbine section (17, 19 in Fig. 1) downstream of the combustor (17,19 are downstream of 16), and an exhaust section (20 Fig. 1) downstream of the turbine section (20 is downstream of 17, 19).
Minelli does not explicitly teach wherein the waste heat recovery heat exchanger is positioned in the exhaust section of the gas turbine engine to cause the fuel to absorb the second heat from core exhaust waste heat in the exhaust section.
Brady teaches with reference to Figs. 2-3, a gas turbine engine (100) with a waste heat recovery heat exchanger (labeled in annotated Fig. 3) positioned in an exhaust section (128 Fig. 3) of the gas turbine engine (waste heat recovery heat exchanger is positioned in exhaust section 128 in annotated Fig. 3), a fuel to absorb heat in the waste heat recovery heat exchanger from core exhaust waste heat ([0053] describes conduit(s) 302 carrying fuel can be positioned in the outer casing 118 in FIG. 2 of the gas turbine 100 and can form loops that are positioned at least partially around a perimeter of the exhaust section 128 that enables the thermal energy from the combustion gases 160, i.e., core exhaust waste heat, to heat the fuel in preparation for combustion, i.e., the fuel absorbs heat in the waste heat recovery heat exchanger).
Minelli modified in view of Brady has waste heat recovery heat exchanger 7010 include loops carrying fuel that are positioned at least partially around a perimeter of the exhaust section in the outer casing of the exhaust section such that the outer casing, i.e., turbine case, is cooled by the fuel while the fuel absorbs second heat transferred from the core exhaust waste heat via the turbine case cooling system components in the exhaust section.
It would have been obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to modify the invention of Minelli such that the waste heat recovery heat exchanger is positioned in an exhaust section of the gas turbine engine, the fuel to absorb the second heat in the waste heat recovery heat exchanger from core exhaust waste heat as taught by Brady to cool the outer casing of the exhaust section while heating the fuel in preparation for combustion.
Response to Arguments
Applicant's arguments filed 05/14/2026 have been fully considered but they are moot in regards to currently amended claim 21 and dependents of claim 21, since currently amended claim 21 has many newly recited limitations compared to the previous version of claim 21. On page 11 of Remarks, regarding the 103 rejections of claim 21 and claims dependent therefrom, Applicant cites the Final Rejection which includes modifying Fig. 7C of Minelli in view of Fig. 6 of Minelli to add a valve to bypass flow and block fuel from flowing to trim heat exchanger 1006 which the office action shows reads on the claim limitation “a valve coupled to the flowline to control a flow rate of the fuel in the first portion of the flowline” which, for clarification, is of claim 21 as filed 11/04/2025. At the top of page 12 of Remarks, Applicant has a statement underlined which includes “this limitation” but then also refers to “the position of the bypass valve” which is in the currently amended claim 21, but then after the underlined statement, Applicant goes back to referring to “the first portion of the flowline” which is not in currently amended claim 21. A bypass valve was previously claimed in now canceled claim 27, but currently amended claim 21 has added the bypass valve but not the rest of the limitations of claim 27 as those limitations have been replaced with new limitations not previously recited in any claims. The next paragraph then refers to first and second modifications of Minelli and, as best understood, are directed to currently amended claim 21, which, as discussed above, has been amended to delete some limitations, add a number of newly recited limitations and adds a bypass valve. On page 13, Applicant says “Minelli does not teach or suggest a bypass valve coupled to the second branch section to control…” which are limitations not previously recited in any claims. On pages 13-14, Applicant says Brady does not teach or suggest the same limitations.
The current 103 rejection of currently amended claim 21, relies on prior art Minelli Fig. 7C modified in view of Fig. 6 and modified in view of prior art Brady but relies on interpretations of figures and citations in view of currently amended claim 21.
Applicant’s arguments regarding claim 29 on pages 14-17 appear to be verbatim of arguments used for claim 21, although currently amended claim 21 and currently amended 29 have significant differences in their respective claim limitations.
Applicant's arguments filed 05/14/2026 have been fully considered but they are not persuasive regarding currently amended claim 29 which has been amended to clarify some claim language but has added no newly recited limitations.
On pages 14-15, Applicant cites the Final Rejection of claim 29 which relies on Minelli Fig. 7C as modified in view of Minelli Fig. 6 to have a valve coupled to the flowline to control a flow rate of the fuel in the first portion of the flowline, and as modified, Minelli is capable of having the valve block the fuel from entering the first portion of the flowline when the bypass valve causes the portion of the second heat to be absorbed from the fuel as claimed.
Applicant argues on page 15 that this capability of the system is inconsistent with the actual teachings of Minelli and then cites the beginning sentences of [0042] of Minelli. However, [0042] as cited in the 103 rejection of claim 29 also states right after the beginning sentences: “However, either, or each, heat exchanger 1004, 1006 may be provided with a bypass to allow some of the fuel to avoid passing through the respective heat exchanger, for example in the form of a fuel bypass pipe 1005 as shown in FIG. 6. A valve (not shown) may determine what proportion of the fuel passes through the heat exchanger 1004 and what proportion through the bypass pipe 1005. In various implementations, a bypass pipe may be provided for each heat exchanger 1004, 1006, allowing a portion of the fuel to avoid either or both heat exchangers.” Therefore, the system of Minelli Fig. 7C as modified in view of Fig. 6 having a bypass line and valve to bypass trim heat exchanger 1006 is consistent with the teachings of Minelli and that this system of Minelli is capable of having the valve block the fuel from entering the first portion of the flowline when the bypass valve (7011 in Fig. 7C) causes the portion of the second heat to be absorbed from the fuel as claimed is consistent with the teachings of Minelli.
Then Applicant argues regarding heat exchanger 1004 that Minelli suggests in several cited paragraphs that only fuel which passes through 1004 flows through waste heat recovery heat exchanger 7010 and that fuel directed to 7010 has also passed through trim heat exchanger 1006 which relies again on the first part of [0420]. However, as cited in the 103 rejection, [0503] of Minelli clearly teaches variations of the different embodiments and states “Whilst FIG. 6 shows an implementation with a bypass pipe 1005 but no recirculation, and FIGS. 7A-7C show implementations with no bypass pipe (at least not for the primary heat exchanger—FIGS. 6A and 6C do provide a route for some of the fuel reaching the combustor 16 to bypass the secondary heat exchanger whilst the rest of the fuel passes through it) but with a recirculation pipe 6011, it will be appreciated that one or more bypass pipes and/or one or more recirculation pipes may be provided together in various implementations.” Therefore, the system of Minelli Fig. 7C in view of Fig. 6 is capable of having the valve block fuel to 1006 while also having bypass valve 7011 cause the portion of the second heat to be absorbed from the fuel by having a portion of fuel bypass 7010 and then downstream mix with fuel which has passed through 7010.
On page 16 of Remarks first paragraph, Applicant states a person of ordinary skill in the art would not be motivated to block the fuel from flowing through trim heat exchanger 1006 when the bypass valve 7011 causes the portion of the fuel to bypass waste heat recovery heat exchanger 7010 because Minelli teaches controlling bypass valve 7011 is based on a need of auxiliary systems and that any fuel not needed for 7010 may be returned to the main fuel flow path/combustor 16 and cites [0428], and 7011 having a portion of fuel to bypass 7010 is not for causing the fuel to reach a certain temperature. However, as discussed above in the 103 rejection, one of ordinary skill in the art is motivated to modify Minelli Fig. 7C to include a valve coupled to the flowline to control a flow rate of the fuel in the first portion of the flowline in view of Minelli Fig. 6 because controlling the fuel flow by bypassing of one or more heat exchangers can assist in heat management such as influencing fuel temperature on entry to the combustor 16 or pump 1003, or amount of heat transferred to the fuel per [0425]. As modified, the system of Minelli, which is an apparatus, is capable of having the valve positioned to block the fuel while the bypass valve is positioned to bypass a portion of fuel which results in the intended use of the bypass valve causes the portion of the second heat to be absorbed from the fuel.
In the second paragraph on page 16 of Remarks, Applicant’s arguments pertain to the intended use of the valve and the bypass valve, while claim 29 claims an apparatus such that these arguments are not relevant to claim 29. However, to clarify, Minelli discloses 7010 is a turbine case cooling system, and as such, fuel would absorb heat after passing through 7010; and Minelli teaches in [0503] that control of the system may comprise controlling fuel flow through the heat exchangers as well as bypassing the heat exchangers.
Therefore, Minelli does teach all that is claimed in claim 29.
Applicant argues on page 18 of Remarks regarding claim 36 that Minelli does not even suggest fuel temperature would increase or decrease in 7010. However, Minelli discloses 7010 is a turbine case cooling system, and as such, fuel would absorb heat after passing through 7010.
Then Applicant makes the same arguments regarding modifying Minelli Fig. 7C in view of Fig. 6 of Minelli as were made regarding claim 29. In addition to Examiner’s response given above regarding claim 29, Minelli teaches controller 58 is used to actively manage fuel and/or oil flows through and around the heat exchangers 1004, 1006, 2020 and controller 58 may be a part of, or provided by, an EEC, or may be a separate unit; 58 may receive inputs from one or more temperature sensors 1009, and may control one or more valves, and/or the pump 1003, based on the received data and one or more oil feed pumps and/or scavenge pumps may also be controlled by the controller, such that 58 controls the valves in order to control fuel flow to or bypassed around the heat exchangers in order to control fuel temperature. As described in the 103 rejection above, Minelli Fig. 7C modified in view of Fig. 6 of Minelli teaches all that is claimed in currently amended claim 36.
Applicant does not argue the dependent claims.
Conclusion
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/A.J.H./Examiner, Art Unit 3741
/GERALD L SUNG/Primary Examiner, Art Unit 3741
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