DETAILED ACTION
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and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114.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 04/17/2025 has been entered.
Claim Objections
Claims are objected to because of the following informalities:
it is thought that it is needed to change line 24 of claim 1 accordingly: “the turbomachinery bearings and” (the same changes should also be made to claims 3-5, 8 (at two locations), 9, 16 and 17); and
change line 2 of claim 20 accordingly: “the at least one fuel-lubricant .
Appropriate correction is required.
Claim Rejections - 35 USC § 112
The following is a quotation of the first paragraph of 35 U.S.C. 112(a):
(a) IN GENERAL.—The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor or joint inventor of carrying out the invention.
The following is a quotation of the first paragraph of pre-AIA 35 U.S.C. 112:
The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor of carrying out his invention.
Claims 6 and 19 are rejected under 35 U.S.C. 112(a) or 35 U.S.C. 112 (pre-AIA ), first paragraph, as failing to comply with the written description requirement. The claim(s) contains subject matter which was not described in the specification in such a way as to reasonably convey to one skilled in the relevant art that the inventor or a joint inventor, or for applications subject to pre-AIA 35 U.S.C. 112, the inventor(s), at the time the application was filed, had possession of the claimed invention. Claim 6 recites a “range from 1.5 to 4.5”. This does not appear to be proper because the maximum amount that can be achieved by claim 6 “ratio” is 0.70/0.25 = 2.8 given the range of the “first proportion” of claim 1. Therefore one of ordinary skill would not consider possession of invention to be shown.
Claim 19 recites a “range from 1.5 to 4.5”. This does not appear to be proper because the maximum amount that can be achieved by claim 19 “ratio” is 0.70/0.25 = 2.8 given the range of the “first proportion” of claim 16. Therefore one of ordinary skill would not consider possession of invention to be shown.
Claim Rejections - 35 USC § 112
The following is a quotation of 35 U.S.C. 112(d):
(d) REFERENCE IN DEPENDENT FORMS.—Subject to subsection (e), a claim in dependent form shall contain a reference to a claim previously set forth and then specify a further limitation of the subject matter claimed. A claim in dependent form shall be construed to incorporate by reference all the limitations of the claim to which it refers.
The following is a quotation of pre-AIA 35 U.S.C. 112, fourth paragraph:
Subject to the following paragraph [i.e., the fifth paragraph of pre-AIA 35 U.S.C. 112], a claim in dependent form shall contain a reference to a claim previously set forth and then specify a further limitation of the subject matter claimed. A claim in dependent form shall be construed to incorporate by reference all the limitations of the claim to which it refers.
Claim 4 rejected under 35 U.S.C. 112(d) or pre-AIA 35 U.S.C. 112, 4th paragraph, as being of improper dependent form for failing to further limit the subject matter of the claim upon which it depends, or for failing to include all the limitations of the claim upon which it depends. The claim 1 range of 0.25 to 0.70 is broadened in claim 4 (rather than further limiting the range). Applicant may cancel the claim(s), amend the claim(s) to place the claim(s) in proper dependent form, rewrite the claim(s) in independent form, or present a sufficient showing that the dependent claim(s) complies with the statutory requirements.
Claim Rejections - 35 USC § 103
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.
Claim(s) 1-3, 8, 14, 16, 17 and 21 is/are rejected under 35 U.S.C. 103 as being unpatentable over Pub. No.: US 2021/0190008 A1 (Gaskell) in view of US Patent 6,253,538 (Sampath), Pub. No.: US 2015/0361811 A1 (Schwarz), Pub. No.: US 2022/0403779 A1 (Walz) and Pub. No.: US 2021/0172375 A1 (Bosak).
Regarding claims 1, 3 and 8, Gaskell discloses (see fig. 1) (claim 1) a gas turbine engine 10 for an aircraft (see abstract) comprising:
- an engine core 11 comprising a compressor 14,15, a combustor 16, a turbine 17,19, and a core shaft 26 connecting the turbine to the compressor, wherein the core shaft has a core shaft maximum take-off speed in the range of from 5500 rpm to 9500 rpm (see par. 23; both ranges in par. 23 fall within the claimed range);
- a fan 23 comprising a plurality of fan blades (at 23) and arranged upstream (see fig. 1) of the engine core;
- turbomachinery bearings (see annotated figure below);
- a power gearbox 30 adapted to drive the fan at a lower rotation speed (see par. 10) than the turbine; and
- a heat management system configured to provide lubrication and cooling to turbomachinery bearings (see par. 360 and 367 stating that oil is used for lubricating bearings and thus a lubrication system is provided; one of ordinary skill understands that heat will be transferred to the oil when the oil is at a lower temperature than the bearing for example, and thus the limitation regarding cooling the bearings is met); 85% of the core shaft maximum take-off speed (see par. 118; par. 118 discusses the operating range of the core shaft from 1500 rpm to 6200 rpm, the upper bound 6200 rpm being that speed reached at maximum take-off; therefore the speed of 85% of the core shaft maximum take-off speed would be reached at least during the increase from the lower bound of 1500 rpm to the maximum speed at take-off).
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Gaskell does not disclose (claim 1) a lean burn combustor; the heat management system configured to provide lubrication and cooling to the gearbox, and comprising a pipe assembly, which includes a first lubricant circuit and a second lubricant circuit separate from the first lubricant circuit, adapted to provide a lubricant flow to the gearbox and turbomachinery bearings, at least one air-lubricant heat exchanger configured to dissipate a first amount of heat to a first heat sink, the at least one air-lubricant heat exchanger being part of the second lubricant circuit, a bypass circuit, which is part of the second lubricant circuit, to bypass lubricant past the least one air-lubricant heat exchanger, and at least one fuel-lubricant heat exchanger configured to dissipate a second amount of heat to a second heat sink, the at least one fuel- lubricant heat exchanger being part of the second lubricant circuit, wherein the first heat sink is air and the second heat sink is fuel, wherein the at least one air-lubricant heat exchanger and the at least one fuel-lubricant heat exchanger are configured to provide the first amount of heat and the second amount of heat by controlling flow through the at least one air-lubricant heat exchanger and the at least one fuel-lubricant heat exchanger via the bypass circuit so that a first proportion of heat generated by the gearbox and the turbomachinery and dissipated to air defined as
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85%MTO at 85% of the core shaft maximum take-off speed is in the range of from 0.25 to 0.70; (claim 3) the first proportion of heat generated by the gearbox and the turbomachinery and dissipated to air is in the range of from 0.35 to 0.70; and (claim 8) a second proportion of heat generated by the gearbox and the turbomachinery and dissipated to air is defined as
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65%MTO at 65% of the core shaft maximum take-off speed, the heat management system being configured to provide the first amount of heat and the second amount of heat such that the second proportion of heat generated by the gearbox and the turbomachinery and dissipated to air is in the range of from 0.60 to 1.
Sampath teaches a gas turbine (see col. 1, ll. 15-20) and further teaches a lean burn combustor (see title and see combustor 10 in fig. 1 wherein combustor can be forward or reverse flow, see col. 6, ll. 10-15). It is further noted that “when a patent claims a structure already known in the prior art that is altered by the mere substitution of one element for another known in the field, the combination must do more than yield a predictable result.” KSR International Co. v. Teleflex Inc., 82 USPQ2d 1385 at 1395 (U.S. 2007) (MPEP 2143 I.B.).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the current invention to substitute the combustor of Sampath (i.e. lean burn combustor) for the combustor of Gaskell for the purpose of substituting one known element for another in order to provide the expected result of providing a combustor to combust air with fuel and in order to facilitate reducing harmful emissions (see Sampath col. 1, ll. 5-10).
Schwarz teaches (see figs. 1 and 9) a gas turbine 20 and further teaches a heat management system 180 configured to provide lubrication (via pipes 95 and 109 and lubrication pumps 182,184) and cooling (see discussion of heat exchangers below) to a gearbox 32 (and bearings 64), and comprising a pipe assembly 95,109, which includes a first lubricant circuit 78’’’ and a second lubricant circuit 76‘’’ separate from the first lubricant circuit 78’’’, adapted to provide a lubricant flow to the gearbox 32 and turbomachinery bearings 64, at least one air-lubricant heat exchanger 92 configured to dissipate a first amount of heat to a first heat sink (air from valve 80; see par. 47), the at least one air-lubricant heat exchanger 92 being part of the second lubricant circuit 76’’’, wherein the first heat sink is air (air from valve 80; see par. 47).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the current invention to provide Gaskell in view of Sampath with the heat management system configured to provide lubrication and cooling to the gearbox, and comprising a pipe assembly, which includes a first lubricant circuit and a second lubricant circuit separate from the first lubricant circuit, adapted to provide a lubricant flow to the gearbox and turbomachinery bearings, at least one air-lubricant heat exchanger configured to dissipate a first amount of heat to a first heat sink, the at least one air-lubricant heat exchanger being part of the second lubricant circuit, wherein the first heat sink is air as taught by Schwarz in order to facilitate improved lubrication and cooling (see Schwarz pars. 5-6).
Schwarz embodiment of fig. 10 teaches a heat management system 180 with a second loop 76IV (connected to turbomachinery gearbox 32 and in addition to a first loop 78IV) and further teaches at least one fuel-lubricant heat exchanger 146 configured to dissipate a second amount of heat to a second heat sink (the heat exchanger removes heat from lubricant that is heated by the engine, see par. 49, bottom; such heat is removed from the lubricant by heat sink fuel by way of the passages of the fuel-lubricant heat exchanger 146, see pars. 54 and 57), the at least one fuel-lubricant heat exchanger 146 being part of the second lubricant circuit 76IV, and the second heat sink is fuel (the heat exchanger remove heat from lubricant that is heated by the engine, see par. 49, bottom; such heat is removed from the lubricant by heat sink fuel by way of the passages of the fuel-lubricant heat exchanger 146, see pars. 54 and 57).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the current invention to provide Gaskell in view of Sampath and Schwarz with at least one fuel-lubricant heat exchanger configured to dissipate a second amount of heat to a second heat sink, the at least one fuel-lubricant heat exchanger being part of the second lubricant circuit, wherein the second heat sink is fuel as taught by Schwarz in order to facilitate further improved lubrication and cooling (see Schwarz pars. 5-6). Including the instant fuel-lubricant heat exchanger permits the heat management system of the combination to keep the energy dissipated by the fuel in the gas turbine system and thus represents an improvement in efficiency compared to waste heat dissipated to air in the bypass duct and then to the environment.
Walz teaches (see figs. 1 and 2) a gas turbine 10 and further teaches a bypass circuit (bypass pipe 35; and bypass valve 36 in fig. 2, or bypass valve 136 in figs. 3A-3B), which is part of a lubricant circuit (see e.g. conduits 33,35 of lubrication system 28 in fig. 2), to bypass lubricant F5 past at least one air-lubricant heat exchanger 41 (portion F5 of lubricant F1 bypasses air-lubricant heat exchanger 41, see par. 37, bottom).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the current invention to provide Gaskell in view of Sampath and Schwarz with a bypass circuit, which is part of the second lubricant circuit, to bypass lubricant past the least one air-lubricant heat exchanger as taught by Walz in order to facilitate providing oil cooling that can adapt to the operating conditions of the aircraft engine in a simple, compact and cost-effective manner (see Walz pars. 2 and 30).
The combination of Gaskell in view of Sampath, Schwarz and Walz teach (claim 1) wherein the at least one air-lubricant heat exchanger (heat exchanger 92 in Schwarz fig. 9) and the at least one fuel-lubricant heat exchanger (heat exchanger 146 in Schwarz fig. 10) are configured to provide the first amount of heat and the second amount of heat by controlling flow (regarding air-lubricant heat exchanger 92, air flow is controlled by valve 80, and the lubricant flow is controlled with pump 182 in Schwarz fig. 9 and the bypass circuit (bypass pipe 35; and bypass valve 36 in fig. 2, or bypass valve 136 in figs. 3A-3B) in Walz fig. 2; regarding fuel-lubricant heat exchanger 146 the lubricant flow is controlled with pump 182 in Schwarz fig. 9) through the at least one air-lubricant heat exchanger 92 and the at least one fuel-lubricant heat exchanger 146 via the bypass circuit so that a first proportion of heat generated by the gearbox (see e.g., gearbox 94 in Schwarz fig. 9 representing the gearbox disclosed by Gaskell above) and the turbomachinery (see e.g. bearings 64 in Schwarz fig. 9 representing the bearings disclosed by Gaskell above; see claim objection above) and dissipated to air defined as
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85%MTO at 85% of the core shaft maximum take-off speed (disclosed by Gaskell above) (claims 1 and 3) is in a range (since the flow is controlled the instant first proportion regarding the first and second amount of heats will be in a range); and (claim 8) a second proportion of heat generated by the gearbox and the turbomachinery and dissipated to air is defined as
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65%MTO at 65% of the core shaft maximum take-off speed (65% of the 6200 rpm MTO, see pars. 118 and 165, of Gaskell is 4060 rpm; the Gaskell core shaft has a running speed in the range of 1500 rpm to 6200 rpm, see par. 21, and thus Gaskell operates at the instant 65% value of 4060 rpm and thus one of ordinary skill understands that the heat management system of the combination is used to dissipate heat at the instant rpm), the heat management system being configured to provide the first amount of heat and the second amount of heat such that the second proportion of heat generated by the gearbox and the turbomachinery and dissipated to air is in a range (since the flow is controlled the instant second proportion regarding the first and second amount of heats will be in a range). The combination does not teach (claim 1) the first proportion in a range from 0.25 to 0.70; (claim 3) the first proportion in a range from 0.35 to 0.70; and (claim 8) the second proportion in a range from 0.60 to 1.
Here, Walz and Bosak teach that the first proportion is result effective across engine operation rpm ranges. The first proportion can be thought of as the comparison of heat transferred from the oil to the at least one fuel-lubricant heat exchanger compared to that transferred by the oil to the at least one first air-lubricant heat exchanger (see instant application publication PGPub US 2024/0110511 A1 at par. 11, bottom, and pars. 12-13). As an overall idea, it is preferred to use the at least one fuel-lubricant heat exchanger to dissipate heat from the oil. This preserves energy from the engine system by using waste heat from the oil (see Bosak par. 6) and makes the engine more efficient (see Walz pars. 30 and 35) including improving fuel consumption (see Bosak par. 6). However, Bosak further points out (see par. 41) that too much heating of fuel with a fuel-lubricant heat exchanger results in coking and can damage the fuel equipment. Therefore, (see Walz fig. 2) oil flow through an air-lubricant heat exchanger 41 and a fuel-lubricant heat exchanger 42 can include a bypass circuit 35 that bypasses the air-lubricant heat exchanger 41 using variable bypass valve 36 (also see par. 47 pointing out that the bypass valve can be variable) to vary the respective oil flows through the respective heat exchangers (one of ordinary skill understands that the amount of oil flow corresponds to the amount of heat; see Pertinent Prior Art section on page 36 in the office action mailed 07/31/2024). However, if too much oil is directed to the at air-lubricant heat exchanger, there will not be enough heat remaining in the oil at the exit of the air-lubricant heat exchanger to properly heat the fuel with the fuel-lubricant heat exchanger when the gas turbine is operating in a cold operating condition as pointed out by Walz in pars. 2, 37 and 38. Finally, Walz points out that proper balance of heat dissipated to air and fuel, across engine operating conditions, is necessary to avoid overdesigned or heavy equipment (see pars. 2 and 39). Bosak adds that in some scenarios it is more efficient for the engine to dissipate more heat to air rather than to fuel because this can keep the oil from degrading at high temperatures that happens when more emphasis it put on keeping energy in the engine system using the fuel-lubricant heat exchanger (see Bosak pars. 5, 12 and 38, bottom, and 48). Bosak accomplishes this by adjusting the speed of lubricant pumps 14,16 to respective heat exchangers 22,24 as shown in in fig. 9. Thus, ratios of the first amount of heat to the second amount of heat control, or have an effect on, the efficiency of operation of a gas turbine, the durability of the fuel equipment, the quality of the lubricant and the capability of a heat management system to provide enough air and fuel to effectively cool the engine oil across engine operating conditions. A recognition in the prior art that a property is affected by the variable is sufficient to find the variable result-effective (MPEP 2144.05 III. C.).
Therefore, an ordinary skilled worker would recognize that the first proportion represented by the percentage of heat from oil transferred to the at least one first air-lubricant heat exchangers compared to that transferred to the at least one fuel-lubricant heat exchanger is a result effective variable. The prior art also teaches that the such a proportion is important at gas turbine engine operating ranges. See Bosak Figure 4 explaining when it can be more efficient, regarding operational scenarios such as idle and takeoff power of the engine, to emphasize average oil temperature and thus there is minimal impact on thrust specific fuel consumption.
Thus, the claimed wherein (claim 1) the first proportion is in the range of from 0.25 to 0.70, (claim 3) the first proportion is in the range of from 0.35 to 0.70 and (claim 8) the second proportion is in the range of from 0.60 to 1 is found to be an obvious optimization of the prior art obtainable by an ordinary skilled worker through routine experimentation.
Therefore, since the general conditions of the claim, i.e., the at least one first air-lubricant heat exchanger and the at least one fuel-lubricant heat exchanger are configured to provide the first amount of heat and the second amount of heat, were taught in the prior art by Gaskell in view of Sampath, Schwarz and Walz, it is not inventive to discover the optimum workable range by routine experimentation, and it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Gaskell in view of Sampath, Schwarz and Walz’s invention to include wherein the (claim 1) first proportion is in the range of from 0.25 to 0.70, the (claim 3) first proportion is in the range of from 0.35 to 0.70 and (claim 8) the second proportion is in the range of from 0.60 to 1 in order to provide an efficient and cost effective heat management system that adapts to engine operating conditions as suggested and taught by Walz and Bosak. It has been held “where the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation”, In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955).
One of ordinary skill is likely to be able to achieve this range. Applicant disclosure points out (see PGPub. par. 35) that the claimed first proportion corresponds with or near cruise conditions. Bosak discusses heats dissipated by an air-lubricant heat exchanger 24 and a fuel-lubricant heat exchanger 22 and points out that at cruise conditions, the claimed ratio is typically about 60%. Regarding Figure 4 and par. 45, the total oil flow is 7.5 Kg/s and the oil flow to the exchanger 22 is 2.8 Kg/s at ISA and at cruise. This leaves 4.7 Kg/s through exchanger 24. Thus, the at least one first air-lubricant heat exchanger dissipates about 60% of the heat wherein heat corresponds with the oil mass flow rates as discussed in par. 48, such heat being generated from bearings and power gearbox (see par. 4).
The instant combination is also likely to be able to reach the claimed range for additional reasons:
Applicant is not using a specific precise control algorithm with a computer controller to operate applicant heat management system. For example, it is further noted that applicant air-lubricant heat exchanger (Matrix Air-Cooled Oil Cooler (MACOC)) was conventional (see pertinent prior art below); and applicant fuel-lubricant heat exchanger (shell and tube heat exchanger a plate-fin heat exchanger) was conventional as well (see pertinent prior art below). Also applicant is not using a special fuel or lubricant that would change heat transfer properties.
The core speed running shaft speeds of 65%MTO and 85%MTO are common operating scenarios of flight idle and cruise;
the split of oil between the at least one air-lubricant heat exchanger 92 in the second circuit 76’’’ and the at least one fuel-lubricant heat exchanger in the second circuit can be changed in variable amounts by way of:
pumps 182 and 184 in fig. 9 of Schwarz; the pumps can be electrical pumps (see par. 33) and thus can have different speeds and thus pump different amounts of oil into the two circuits 78’’’ and 76’’’ (see fig. 9); this is discussed regarding Bosak above.
bypass valve 136 of Walz that has intermediate positions between open and closed; see par. 47; the valve can vary the amount of oil entering the at air-lubricant heat exchanger in the second loop when optimizing the first proportion; regarding Walz fig. 2, one of ordinary skill understands that the amount of heat transferred to the fuel F3 depends on the amount of oil flowing through the heat exchanger 42 and similarly the amount of heat transferred to the air F2 depends on the amount of oil directed to heat exchanger 41; thus controlling the ratio of oil flow with valve 36/136 controls the first amount of heat and the second amount of heat.
Regarding claim 16, Gaskell discloses (see fig. 1) a method of operating a gas turbine engine 10 for an aircraft (see abstract), the method comprising providing the gas turbine engine comprising:
- an engine core 11 comprising a compressor 14,15, a combustor 16, a turbine 17,19, and a core shaft 26 connecting the turbine to the compressor, wherein the core shaft has a core shaft maximum take-off speed in the range of from 5500 rpm to 9500 rpm (see par. 23; both ranges in par. 23 fall within the claimed range);
- a fan 23 comprising a plurality of fan blades (at 23) and arranged upstream of the engine core;
- turbomachinery bearings (see annotated figure above);
- a power gearbox 30 adapted to drive the fan at a lower rotation speed (see par. 10) than the turbine; and
- a heat management system configured to provide lubrication and cooling to the turbomachinery bearings (see par. 360 and 367 stating that oil is used for lubricating bearings and thus a lubrication system is provided; one of ordinary skill understands that heat will be transferred to the oil when the oil is at a lower temperature than the bearing for example), and 85% of the core shaft maximum take-off speed (see par. 118; such 85% is .85(6200 rpm) that equals 5270 rpm).
Gaskell does not explicitly disclose a lean burn combustor; the heat management system configured to provide lubrication and cooling to the gearbox, and comprising a pipe assembly, which includes a first lubricant circuit and a second lubricant circuit separate from the first lubricant circuit, adapted to provide a lubricant flow to the gearbox and turbomachinery bearings, at least one first air-lubricant heat exchanger configured to dissipate heat to a first heat sink, the at least one first air-lubricant heat exchanger being part of the second lubricant circuit, a bypass circuit, which is part of the second lubricant circuit, to bypass lubricant past the at least one first air-lubricant heat exchanger, at least one fuel-lubricant heat exchanger configured to dissipate a second amount of heat to a second heat sink, the at least one fuel-lubricant heat exchanger being part of the second lubricant circuit, and at least one second air-lubricant heat exchanger arranged in the first lubricant circuit and configured to dissipate heat to the first heat sink; wherein the at least one first air-lubricant heat exchanger and the at least one second air-lubricant heat exchanger together are configured to dissipate a first amount of to the first heat sink, the first heat sink is air and the second heat sink is fuel; and wherein the method comprises operating the at least one first air-lubricant heat exchanger and the at least one fuel-lubricant heat exchanger to provide the first amount of heat and the second amount of heat by controlling flow through the at least one first air- lubricant heat exchanger and the at least one fuel-lubricant heat exchanger via the bypass circuit so that a first proportion of heat generated by the gearbox and the turbomachinery and dissipated to air defined as
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85%MTO at 85% of the core shaft maximum take-off speed is in the range of from 0.25 to 0.70.
Sampath teaches a gas turbine (see col. 1, ll. 15-20) and further teaches a lean burn combustor (see title and see combustor 10 in fig. 1 wherein combustor can be forward or reverse flow, see col. 6, ll. 10-15). It is further noted that “when a patent claims a structure already known in the prior art that is altered by the mere substitution of one element for another known in the field, the combination must do more than yield a predictable result.” KSR International Co. v. Teleflex Inc., 82 USPQ2d 1385 at 1395 (U.S. 2007) (MPEP 2143 I.B.).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the current invention to substitute the combustor of Sampath (i.e. lean burn combustor) for the combustor of Gaskell for the purpose of substituting one known element for another in order to provide the expected result of providing a combustor to combust air with fuel and in order to facilitate reducing harmful emissions (see Sampath col. 1, ll. 5-10).
Schwarz teaches (see figs. 1 and 9) a gas turbine 20 and further teaches a heat management system 180 configured to provide lubrication (via pipes 95 and 109 and lubrication pumps 182,184) and cooling (see discussion of heat exchangers below) to a gearbox 32 (and bearings 64), and comprising a pipe assembly 95,109, which includes a first lubricant circuit 78’’’ and a second lubricant circuit 76‘’’ separate from the first lubricant circuit 78’’’, adapted to provide a lubricant flow to the gearbox 32 and turbomachinery bearings 64, at least one first air-lubricant heat exchanger 92 configured to dissipate heat to a first heat sink (air from valve 80; see par. 47), the at least one first air-lubricant heat exchanger 92 being part of the second lubricant circuit 76‘’’, and at least one second air-lubricant heat exchanger 106 arranged in the first lubricant circuit 78‘’’ and configured to dissipate heat to the first heat sink (air from valve 82); wherein the at least one first air-lubricant heat exchanger 92 and the at least one second air-lubricant heat exchanger 106 together are configured to dissipate a first amount of to the first heat sink (air), the first heat sink is air.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the current invention to provide Gaskell in view of Sampath with the heat management system configured to provide lubrication and cooling to the gearbox, and comprising a pipe assembly, which includes a first lubricant circuit and a second lubricant circuit separate from the first lubricant circuit, adapted to provide a lubricant flow to the gearbox and turbomachinery bearings, at least one first air-lubricant heat exchanger configured to dissipate heat to a first heat sink, the at least one first air-lubricant heat exchanger being part of the second lubricant circuit, and at least one second air-lubricant heat exchanger arranged in the first lubricant circuit and configured to dissipate heat to the first heat sink; wherein the at least one first air-lubricant heat exchanger and the at least one second air-lubricant heat exchanger together are configured to dissipate a first amount of to the first heat sink, the first heat sink is air as taught by Schwarz in order to facilitate in order to facilitate improved lubrication and cooling (see Schwarz pars. 5-6).
Schwarz embodiment of fig. 10 teaches a heat management system 180 with a second loop 76IV (connected to turbomachinery gearbox 32 and in addition to a first loop 78IV) and further teaches at least one fuel-lubricant heat exchanger 146 configured to dissipate a second amount of heat to a second heat sink (the heat exchanger remove heat from lubricant that is heated by the engine, see par. 49, bottom; such heat is removed from the lubricant by heat sink fuel by way of the passages of the fuel-lubricant heat exchanger 146, see pars. 54 and 57), the at least one fuel-lubricant heat exchanger 146 being part of the second lubricant circuit 76IV, and the second heat sink is fuel (the heat exchanger remove heat from lubricant that is heated by the engine, see par. 49, bottom; such heat is removed from the lubricant by heat sink fuel by way of the passages of the fuel-lubricant heat exchanger 146, see pars. 54 and 57).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the current invention to provide Gaskell in view of Sampath and Schwarz with at least one fuel-lubricant heat exchanger configured to dissipate a second amount of heat to a second heat sink, the at least one fuel-lubricant heat exchanger being part of the second lubricant circuit, wherein the second heat sink is fuel as taught by Schwarz in order to facilitate further improved lubrication and cooling (see Schwarz pars. 5-6). Including the instant fuel-lubricant heat exchanger permits the heat management system of the combination to keep the energy dissipated by the fuel in the gas turbine system and thus represents an improvement in efficiency compared to waste heat dissipated to air in the bypass duct and then to the environment.
Walz teaches (see figs. 1 and 2) a gas turbine 10 and further teaches a bypass circuit (bypass pipe 35; and bypass valve 36 in fig. 2, or bypass valve 136 in figs. 3A-3B), which is part of a lubricant circuit (see e.g. conduits 33,35 of lubrication system 28 in fig. 2), to bypass lubricant F5 past at least one air-lubricant heat exchanger 41 (portion F5 of lubricant F1 bypasses air-lubricant heat exchanger 41, see par. 37, bottom).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the current invention to provide Gaskell in view of Sampath and Schwarz with a bypass circuit, which is part of the second lubricant circuit, to bypass lubricant past the least one air-lubricant heat exchanger as taught by Walz in order to facilitate providing oil cooling that can adapt to the operating conditions of the aircraft engine in a simple, compact and cost-effective manner (see Walz pars. 2 and 30).
The combination of Gaskell in view of Sampath, Schwarz and Walz teach wherein the method comprises operating the at least one first air-lubricant heat exchanger (heat exchanger 92 in Schwarz fig. 9) and the at least one fuel-lubricant heat exchanger (heat exchanger 146 in Schwarz fig. 10) to provide the first amount of heat and the second amount of heat by controlling flow (regarding air-lubricant heat exchanger 92, air flow is controlled by valve 80, and the lubricant flow is controlled with pump 182 in Schwarz fig. 9 and the bypass circuit (bypass pipe 35; and bypass valve 36 in fig. 2, or bypass valve 136 in figs. 3A-3B) in Walz fig. 2; regarding fuel-lubricant heat exchanger 146 the lubricant flow is controlled with pump 182 in Schwarz fig. 9) through the at least one first air-lubricant heat exchanger 92 and the at least one fuel-lubricant heat exchanger 146 via the bypass circuit so that a first proportion of heat generated by the gearbox (see e.g., gearbox 94 in Schwarz fig. 9 representing the gearbox disclosed by Gaskell above) and the turbomachinery (see e.g. bearings 64 in Schwarz fig. 9 representing the bearings disclosed by Gaskell above; see claim objection above) and dissipated to air defined as
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85%MTO at 85% of the core shaft maximum take-off speed (disclosed by Gaskell above) is in a range (since the flow is controlled the instant first proportion regarding the first and second amount of heats will be in a range). The combination does not teach the range of from 0.25 to 0.70.
Here, Walz and Bosak teach that the first proportion is result effective across engine operation rpm ranges. The first proportion can be thought of as the comparison of heat transferred from the oil to the at least one fuel-lubricant heat exchanger compared to that transferred by the oil to the at least one first air-lubricant heat exchanger (see instant application publication PGPub US 2024/0110511 A1 at par. 11, bottom, and pars. 12-13). As an overall idea, it is preferred to use the at least one fuel-lubricant heat exchanger to dissipate heat from the oil. This preserves energy from the engine system by using waste heat from the oil (see Bosak par. 6) and makes the engine more efficient (see Walz pars. 30 and 35) including improving fuel consumption (see Bosak par. 6). However, Bosak further points out (see par. 41) that too much heating of fuel with a fuel-lubricant heat exchanger results in coking and can damage the fuel equipment. Therefore, (see Walz fig. 2) oil flow through an air-lubricant heat exchanger 41 and a fuel-lubricant heat exchanger 42 can include a bypass circuit 35 that bypasses the air-lubricant heat exchanger 41 using variable bypass valve 36 (also see par. 47 pointing out that the bypass valve can be variable) to vary the respective oil flows through the respective heat exchangers (one of ordinary skill understands that the amount of oil flow corresponds to the amount of heat; see Pertinent Prior Art section on page 36 in the office action mailed 07/31/2024). However, if too much oil is directed to the at air-lubricant heat exchanger, there will not be enough heat remaining in the oil at the exit of the air-lubricant heat exchanger to properly heat the fuel with the fuel-lubricant heat exchanger when the gas turbine is operating in a cold operating condition as pointed out by Walz in pars. 2, 37 and 38. Finally, Walz points out that proper balance of heat dissipated to air and fuel, across engine operating conditions, is necessary to avoid overdesigned or heavy equipment (see pars. 2 and 39). Bosak adds that in some scenarios it is more efficient for the engine to dissipate more heat to air rather than to fuel because this can keep the oil from degrading at high temperatures that happens when more emphasis it put on keeping energy in the engine system using the fuel-lubricant heat exchanger (see Bosak pars. 5, 12 and 38, bottom, and 48). Bosak accomplishes this by adjusting the speed of lubricant pumps 14,16 to respective heat exchangers 22,24 as shown in in fig. 9. Thus, ratios of the first amount of heat to the second amount of heat control, or have an effect on, the efficiency of operation of a gas turbine, the durability of the fuel equipment, the quality of the lubricant and the capability of a heat management system to provide enough air and fuel to effectively cool the engine oil across engine operating conditions. A recognition in the prior art that a property is affected by the variable is sufficient to find the variable result-effective (MPEP 2144.05 III. C.).
Therefore, an ordinary skilled worker would recognize that the first proportion represented by the percentage of heat from oil transferred to the at least one first air-lubricant heat exchangers compared to that transferred to the at least one fuel-lubricant heat exchanger is a result effective variable. The prior art also teaches that the such a proportion is important at gas turbine engine operating ranges. See Bosak Figure 4 explaining when it can be more efficient, regarding operational scenarios such as idle and takeoff power of the engine, to emphasize average oil temperature and thus there is minimal impact on thrust specific fuel consumption.
Thus, the claimed wherein the first proportion is in the range of from 0.25 to 0.70 is found to be an obvious optimization of the prior art obtainable by an ordinary skilled worker through routine experimentation.
Therefore, since the general conditions of the claim were taught in the prior art by Gaskell in view of Sampath, Schwarz and Walz, it is not inventive to discover the optimum workable range by routine experimentation, and it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Gaskell in view of Sampath, Schwarz and Walz’s invention to include wherein the first proportion is in the range of from 0.25 to 0.70 in order to provide an efficient and cost effective heat management system that adapts to engine operating conditions as suggested and taught by Walz and Bosak. It has been held “where the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation”, In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955).
One of ordinary skill is likely to be able to achieve this range for the same reasons as discussed regarding claim 1 above.
Regarding claim 17, Gaskell discloses (see fig. 1) a method of operating a gas turbine engine 10 for an aircraft (see abstract), the method comprising providing the gas turbine engine comprising:
- an engine core 11 comprising a compressor 14,15, a combustor 16, a turbine 17,19, and a core shaft 26 connecting the turbine to the compressor, wherein the core shaft has a core shaft maximum take-off speed in the range of from 5500 rpm to 9500 rpm (see par. 23; both ranges in par. 23 fall within the claimed range);
- a fan 23 comprising a plurality of fan blades (at 23) and arranged upstream of the engine core;
- turbomachinery bearings (see annotated figure above);
- a power gearbox 30 adapted to drive the fan at a lower rotation speed (see par. 10) than the turbine; and
- a heat management system configured to provide lubrication and cooling to the turbomachinery bearings (see par. 360 and 367 stating that oil is used for lubricating bearings and thus a lubrication system is provided; one of ordinary skill understands that heat will be transferred to the oil when the oil is at a lower temperature than the bearing for example), and 85% of the core shaft maximum take-off speed (see par. 118; such 85% is .85(6200 rpm) that equals 5270 rpm).
Gaskell does not explicitly disclose a lean burn combustor; the heat management system configured to provide lubrication and cooling to the gearbox, and comprising a pipe assembly, which includes a first lubricant circuit and a second lubricant circuit separate from the first lubricant circuit, adapted to provide a lubricant flow to the gearbox and turbomachinery bearings, at least one first air-lubricant heat exchanger configured to dissipate heat to a first heat sink, the at least one first air-lubricant heat exchanger being part of the second lubricant circuit, a bypass circuit, which is part of the second lubricant circuit, to bypass lubricant past the at least one first air-lubricant heat exchanger, at least one fuel-lubricant heat exchanger configured to dissipate a second amount of heat to a second heat sink, the at least one fuel-lubricant heat exchanger being part of the second lubricant circuit, and at least one second air-lubricant heat exchanger arranged in the first lubricant circuit and configured to dissipate heat to the first heat sink; wherein the at least one first air-lubricant heat exchanger and the at least one second air-lubricant heat exchanger together are configured to dissipate a first amount of to the first heat sink, the first heat sink is air and the second heat sink is fuel; and wherein the method comprises operating the at least one first air-lubricant heat exchanger and the at least one fuel-lubricant heat exchanger to provide the first amount of heat and the second amount of heat by controlling flow through the at least one first air- lubricant heat exchanger and the at least one fuel-lubricant heat exchanger via the bypass circuit so that a first proportion of heat generated by the gearbox and the turbomachinery and dissipated to air defined as
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85%MTO at 85% of the core shaft maximum take-off speed is in the range of from 0.45 to 0.70.
Sampath teaches a gas turbine (see col. 1, ll. 15-20) and further teaches a lean burn combustor (see title and see combustor 10 in fig. 1 wherein combustor can be forward or reverse flow, see col. 6, ll. 10-15). It is further noted that “when a patent claims a structure already known in the prior art that is altered by the mere substitution of one element for another known in the field, the combination must do more than yield a predictable result.” KSR International Co. v. Teleflex Inc., 82 USPQ2d 1385 at 1395 (U.S. 2007) (MPEP 2143 I.B.).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the current invention to substitute the combustor of Sampath (i.e. lean burn combustor) for the combustor of Gaskell for the purpose of substituting one known element for another in order to provide the expected result of providing a combustor to combust air with fuel and in order to facilitate reducing harmful emissions (see Sampath col. 1, ll. 5-10).
Schwarz teaches (see figs. 1 and 9) a gas turbine 20 and further teaches a heat management system 180 configured to provide lubrication (via pipes 95 and 109 and lubrication pumps 182,184) and cooling (see discussion of heat exchangers below) to a gearbox 32 (and bearings 64), and comprising a pipe assembly 95,109, which includes a first lubricant circuit 78’’’ and a second lubricant circuit 76‘’’ separate from the first lubricant circuit 78’’’, adapted to provide a lubricant flow to the gearbox 32 and turbomachinery bearings 64, at least one first air-lubricant heat exchanger 92 configured to dissipate heat to a first heat sink (air from valve 80; see par. 47), the at least one first air-lubricant heat exchanger 92 being part of the second lubricant circuit 76‘’’, and at least one second air-lubricant heat exchanger 106 arranged in the first lubricant circuit 78‘’’ and configured to dissipate heat to the first heat sink (air from valve 82); wherein the at least one first air-lubricant heat exchanger 92 and the at least one second air-lubricant heat exchanger 106 together are configured to dissipate a first amount of to the first heat sink (air), the first heat sink is air.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the current invention to provide Gaskell in view of Sampath with the heat management system configured to provide lubrication and cooling to the gearbox, and comprising a pipe assembly, which includes a first lubricant circuit and a second lubricant circuit separate from the first lubricant circuit, adapted to provide a lubricant flow to the gearbox and turbomachinery bearings, at least one first air-lubricant heat exchanger configured to dissipate heat to a first heat sink, the at least one first air-lubricant heat exchanger being part of the second lubricant circuit, and at least one second air-lubricant heat exchanger arranged in the first lubricant circuit and configured to dissipate heat to the first heat sink; wherein the at least one first air-lubricant heat exchanger and the at least one second air-lubricant heat exchanger together are configured to dissipate a first amount of to the first heat sink, the first heat sink is air as taught by Schwarz in order to facilitate in order to facilitate improved lubrication and cooling (see Schwarz pars. 5-6).
Schwarz embodiment of fig. 10 teaches a heat management system 180 with a second loop 76IV (connected to turbomachinery gearbox 32 and in addition to a first loop 78IV) and further teaches at least one fuel-lubricant heat exchanger 146 configured to dissipate a second amount of heat to a second heat sink (the heat exchanger remove heat from lubricant that is heated by the engine, see par. 49, bottom; such heat is removed from the lubricant by heat sink fuel by way of the passages of the fuel-lubricant heat exchanger 146, see pars. 54 and 57), the at least one fuel-lubricant heat exchanger 146 being part of the second lubricant circuit 76IV, and the second heat sink is fuel (the heat exchanger remove heat from lubricant that is heated by the engine, see par. 49, bottom; such heat is removed from the lubricant by heat sink fuel by way of the passages of the fuel-lubricant heat exchanger 146, see pars. 54 and 57).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the current invention to provide Gaskell in view of Sampath and Schwarz with at least one fuel-lubricant heat exchanger confi