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 .
Response to Amendment
This Office action is responsive to the amendment filed 8/12/2026 for application 19364678. Claims 1-20 are pending. Claims 1-13 remain withdrawn from consideration. Claims 14-20 are examined below.
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.
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.
Claims 14-18 & 20 are rejected under 35 U.S.C. 103 as being unpatentable over Weiner 20160024964 in view of Veilleux 20190277201.
Regarding Independent Claim 14, Weiner teaches a gas turbine engine (Fig. 1) for an aircraft, the gas turbine engine comprising:
a combustor (56) arranged to combust a fuel; and
a fuel management system (Fig. 2) arranged to provide the fuel to the combustor (para. [0028]), wherein the fuel management system comprises:
two fuel-oil heat exchangers (ENGINE FOC and HIGH PRESSURE FOC) arranged to have oil (from OIL TANK AOC) and the fuel (see FUEL METERING element inline with heat exchangers) flow therethrough, the two fuel-oil heat exchangers arranged to transfer heat between the oil and the fuel and comprising a primary fuel-oil heat exchanger (ENGINE FOC) and a secondary fuel-oil heat exchanger (HIGH PRESSURE FOC);
a fuel pump (see Fig. 1: Annotated Fig. 2 from Weiner below, annotated fuel pump) arranged to deliver the fuel to the combustor, wherein the fuel pump is located between the two fuel-oil heat exchangers (between ENGINE FOC AND HIGH PRESSURE FOC).
Weiner fails to teach a controller configured to control the fuel management system so as to raise the fuel temperature to at least 135°C on entry to the combustor at cruise conditions.
Veilleux teaches a controller (Fig. 2A, controller 206) configured to control fuel heating based on the dissolved oxygen concentration of the fuel (paras. [0053], [0055], [0056]), with the dissolved oxygen concentration decreasing with altitude and permitting the fuel to absorb more heat without coking (see Figs. 4B & 4C), which would result in the fuel being able to absorb more heat without coking at cruise due to the altitude (Figs. 4B, 4C and at para. [0036]). The capability of absorbing more heat permits increased operational efficiency (para. [0002]).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Weiner’s gas turbine engine to include a controller configured to control the heat exchange system based on the dissolved oxygen concentration of the fuel, as taught by Veilleux, in order to provide additional heat to the fuel during heating when the fuel is capable of absorbing the additional heat without coking (Veilleux; para. [0056]).
While Weiner in view of Veilleux fails to expressly teach the temperature to which the fuel is heated at cruise, Veilleux clearly shows the fuel coking threshold increasing from 250°F to over 325° (121°C to 162°C), depending on dissolved oxygen, which overlaps the claimed range. Veilleux teaches that as the ability to increase the heat absorption of the fuel increases, operational efficiency increases (para. [0002]). Thus, the fuel temperature is found to be a result-effective variable which permits increasing operational efficiency while being bounded at an upper range in view of coking concerns.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Weiner in view of Veilleux’s gas turbine engine such that the controller is configured to control the fuel management system to heat the fuel to at least 135°C on entry to the combustor at cruise conditions as a matter of routine optimization to determine the temperature range of the fuel which increases operational efficiency while avoiding coking. There was a reasonable expectation of success in view of Veilleux’s teaching of fuel coking temperatures increasing beyond 162°C, which would permit the fuel to be heated to some margin just below that while avoiding coking. A particular parameter must first be recognized as a result-effective variable, i.e., a variable which achieves a recognized result, before the determination of the optimum or workable ranges of said variable might be characterized as routine experimentation. See MPEP 2144.05 II(A). 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). See MPEP 2144.05 II(B).
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Figure 1: Annotated Fig. 2 from Weiner
Regarding Dependent Claim 15, Weiner in view of Veilleux teaches the invention as claimed and as discussed above for claim 14, and Weiner in view of Veilleux teaches, as discussed above for claim 14, the controller (Fig. 2A, controller 206) is configured to control fuel heating based on the dissolved oxygen concentration of the fuel (paras. [0053], [0055], [0056]), with the dissolved oxygen concentration decreasing with altitude and permitting the fuel to absorb more heat without coking (see Figs. 4B & 4C), which would result in the fuel being able to absorb more heat without coking at cruise due to the altitude (Figs. 4B, 4C and at para. [0036]). The capability of absorbing more heat permits increased operational efficiency (para. [0002]).
While Weiner in view of Veilleux fails to expressly teach the temperature to which the fuel is heated at cruise, Veilleux clearly shows the fuel coking threshold increasing from 250°F to over 325° (121°C to 162°C), depending on dissolved oxygen, which overlaps the claimed range. Veilleux teaches that as the ability to increase the heat absorption of the fuel increases, operational efficiency increases (para. [0002]). Thus, the fuel temperature is found to be a result-effective variable which permits increasing operational efficiency while being bounded at an upper range in view of coking concerns.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Weiner in view of Veilleux’s gas turbine engine such that the controller is configured to control the fuel management system to heat the fuel to between 135°C and 170°C on entry to the combustor at cruise conditions as a matter of routine optimization to determine the temperature range of the fuel which increases operational efficiency while avoiding coking. There was a reasonable expectation of success in view of Veilleux’s teaching of fuel coking temperatures increasing beyond 162°C, which would permit the fuel to be heated to some margin just below that while avoiding coking. A particular parameter must first be recognized as a result-effective variable, i.e., a variable which achieves a recognized result, before the determination of the optimum or workable ranges of said variable might be characterized as routine experimentation. See MPEP 2144.05 II(A). 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). See MPEP 2144.05 II(B).
Regarding Dependent Claim 16, Weiner in view of Veilleux teaches the invention as claimed and as discussed above for claim 14, and Weiner in view of Veilleux teaches, as discussed above for claim 14, the controller (Fig. 2A, controller 206) is configured to control fuel heating based on the dissolved oxygen concentration of the fuel (paras. [0053], [0055], [0056]), with the dissolved oxygen concentration decreasing with altitude and permitting the fuel to absorb more heat without coking (see Figs. 4B & 4C), which would result in the fuel being able to absorb more heat without coking at cruise due to the altitude (Figs. 4B, 4C and at para. [0036]). The capability of absorbing more heat permits increased operational efficiency (para. [0002]).
While Weiner in view of Veilleux fails to expressly teach the temperature to which the fuel is heated at cruise, Veilleux clearly shows the fuel coking threshold increasing from 250°F to over 325° (121°C to 162°C), depending on dissolved oxygen, which overlaps the claimed range. Veilleux teaches that as the ability to increase the heat absorption of the fuel increases, operational efficiency increases (para. [0002]). Thus, the fuel temperature is found to be a result-effective variable which permits increasing operational efficiency while being bounded at an upper range in view of coking concerns.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Weiner in view of Veilleux’s gas turbine engine such that the controller is configured to control the fuel management system to heat the fuel to between 150°C and 170°C on entry to the combustor at cruise conditions as a matter of routine optimization to determine the temperature range of the fuel which increases operational efficiency while avoiding coking. There was a reasonable expectation of success in view of Veilleux’s teaching of fuel coking temperatures increasing beyond 162°C, which would permit the fuel to be heated to some margin just below that while avoiding coking. A particular parameter must first be recognized as a result-effective variable, i.e., a variable which achieves a recognized result, before the determination of the optimum or workable ranges of said variable might be characterized as routine experimentation. See MPEP 2144.05 II(A). 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). See MPEP 2144.05 II(B).
Regarding Dependent Claim 17, Weiner in view of Veilleux teaches the invention as claimed and as discussed above for claim 14, and Weiner further teaches the fuel management system further comprises: a recirculation valve located downstream of the primary fuel-oil heat exchanger, the recirculation valve arranged to allow a controlled amount of fuel which has passed through the primary fuel-oil heat exchanger to be returned to an inlet of the primary fuel-oil heat exchanger (BYPASS DIRECTION CONTROL VALVE permits controlled amount of fuel which has passed through ENGINE FOC to be returned via the annotated recirculation line, see Fig. 1: Annotated Fig. 2 from Weiner above, to the inlet of ENGINE FOC).
Regarding Dependent Claim 18, Weiner in view of Veilleux teaches the invention as claimed and as discussed above for claim 14, and Weiner further teaches the secondary fuel-oil heat exchanger is a servo fuel-oil heat exchanger (the label “servo” does not convey additional structure to the secondary fuel-oil heat exchanger, it is merely a label indicating an intended use, thus the term “servo fuel-oil heat exchanger” does not distinguish over Weiner’s HIGH PRESSURE FOC, which is capable of provide heated fuel to be used for servos downstream, but this is not required in the claim).
Regarding Dependent Claim 20, Weiner in view of Veilleux teaches the invention as claimed and as discussed above for claim 14, and Weiner further teaches the fuel management system is arranged such that the fuel flows through the primary fuel-oil heat exchanger prior to flowing through the secondary fuel-oil heat exchanger (fuel passes through ENGINE FOC prior to flowing through HIGH PRESSURE FOC) whereas the oil flows through the secondary fuel-oil heat exchanger prior to flowing through the primary fuel-oil heat exchanger (oil flows through HIGH PRESSURE FOC prior to flowing through ENGINE FOC).
Double Patenting
The nonstatutory double patenting rejection is based on a judicially created doctrine grounded in public policy (a policy reflected in the statute) so as to prevent the unjustified or improper timewise extension of the “right to exclude” granted by a patent and to prevent possible harassment by multiple assignees. A nonstatutory double patenting rejection is appropriate where the conflicting claims are not identical, but at least one examined application claim is not patentably distinct from the reference claim(s) because the examined application claim is either anticipated by, or would have been obvious over, the reference claim(s). See, e.g., In re Berg, 140 F.3d 1428, 46 USPQ2d 1226 (Fed. Cir. 1998); In re Goodman, 11 F.3d 1046, 29 USPQ2d 2010 (Fed. Cir. 1993); In re Longi, 759 F.2d 887, 225 USPQ 645 (Fed. Cir. 1985); In re Van Ornum, 686 F.2d 937, 214 USPQ 761 (CCPA 1982); In re Vogel, 422 F.2d 438, 164 USPQ 619 (CCPA 1970); In re Thorington, 418 F.2d 528, 163 USPQ 644 (CCPA 1969).
A timely filed terminal disclaimer in compliance with 37 CFR 1.321(c) or 1.321(d) may be used to overcome an actual or provisional rejection based on nonstatutory double patenting provided the reference application or patent either is shown to be commonly owned with the examined application, or claims an invention made as a result of activities undertaken within the scope of a joint research agreement. See MPEP § 717.02 for applications subject to examination under the first inventor to file provisions of the AIA as explained in MPEP § 2159. See MPEP § 2146 et seq. for applications not subject to examination under the first inventor to file provisions of the AIA . A terminal disclaimer must be signed in compliance with 37 CFR 1.321(b).
The filing of a terminal disclaimer by itself is not a complete reply to a nonstatutory double patenting (NSDP) rejection. A complete reply requires that the terminal disclaimer be accompanied by a reply requesting reconsideration of the prior Office action. Even where the NSDP rejection is provisional the reply must be complete. See MPEP § 804, subsection I.B.1. For a reply to a non-final Office action, see 37 CFR 1.111(a). For a reply to final Office action, see 37 CFR 1.113(c). A request for reconsideration while not provided for in 37 CFR 1.113(c) may be filed after final for consideration. See MPEP §§ 706.07(e) and 714.13.
The USPTO Internet website contains terminal disclaimer forms which may be used. Please visit www.uspto.gov/patent/patents-forms. The actual filing date of the application in which the form is filed determines what form (e.g., PTO/SB/25, PTO/SB/26, PTO/AIA /25, or PTO/AIA /26) should be used. A web-based eTerminal Disclaimer may be filled out completely online using web-screens. An eTerminal Disclaimer that meets all requirements is auto-processed and approved immediately upon submission. For more information about eTerminal Disclaimers, refer to www.uspto.gov/patents/apply/applying-online/eterminal-disclaimer.
Claims 14-16 & 19-20 are rejected on the ground of nonstatutory double patenting as being unpatentable over claims 11-15 of U.S. Patent No. 12410756 in view of Weiner.
The reference patent claims 11-15 teach each and every limitation of the instant claims except the number of fuel-oil heat exchangers, the positioning of the pump between the heat exchangers, and the specific ranges to which the fuel is heated.
Weiner teaches a gas turbine engine (Fig. 1) for an aircraft, the gas turbine engine comprising: a combustor (56) arranged to combust a fuel; and a fuel management system (Fig. 2) arranged to provide the fuel to the combustor (para. [0028]), wherein the fuel management system comprises: two fuel-oil heat exchangers (ENGINE FOC and HIGH PRESSURE FOC) arranged to have oil (from OIL TANK AOC) and the fuel (see FUEL METERING element inline with heat exchangers) flow therethrough, the two fuel-oil heat exchangers arranged to transfer heat between the oil and the fuel and comprising a primary fuel-oil heat exchanger (ENGINE FOC) and a secondary fuel-oil heat exchanger (HIGH PRESSURE FOC); a fuel pump (see Fig. 1: Annotated Fig. 2 from Weiner below, annotated fuel pump) arranged to deliver the fuel to the combustor, wherein the fuel pump is located between the two fuel-oil heat exchangers (between ENGINE FOC AND HIGH PRESSURE FOC).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the reference patent’s gas turbine engine to include two fuel-oil heat exchangers with a pump between them, as taught by Weiner, because a) the prior art contained a device which differed from the claimed device by the substitution of some components with other components (the reference patent’s heat exchanger and pump arrangement versus the claimed heat exchanger and pump arrangement taught by Weiner), b) the substituted components and their functions were known in the art (both the reference patent’s arrangement and Weiner’s arrangement were known for heating fuel/cooling oil and pumping fuel in a fuel system for a gas turbine), and c) one of ordinary skill in the art could have substituted one known element for another and the results of the substitution would have been predictable (either the reference patent’s arrangement or Weiner’s arrangement could have been used to predictably provide pumped, heated fuel and cooled oil in a gas turbine engine). It has been held 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., et al., 82 USPQ2d 1385, 1395 (2007) (citing United States v. Adams, 383 US 39, 50-51 (1966)). See MPEP 2143 I(B).
The reference patent’s range of temperatures to heat the fuel overlap the claimed ranges and thus the claimed ranges were obvious. In the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exists. In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990). See MPEP 2144.05 I.
Claims 14-16 are rejected on the ground of nonstatutory double patenting as being unpatentable over claim 1 of U.S. Patent No. 12669090.
Regarding Claims 14-16, the reference patent claim 1 recites each and every limitation of the instant claims except the reference patent recites a range of between 150°C to 170°C for fuel heating. This range is identical to the range claimed in claim 16 and is narrower, and thus anticipates, the ranges claimed in claims 14-15.
Claim 19 is rejected on the ground of nonstatutory double patenting as being unpatentable over claim 13 of U.S. Patent No. 12669090 in view of Veilleux.
Regarding Dependent Claim 19, the reference patent claim 13 recites each and every limitation of the instant claims except the controller being configured to heat the fuel to the claimed range.
Veilleux teaches a controller (Fig. 2A, controller 206) configured to control fuel heating based on the dissolved oxygen concentration of the fuel (paras. [0053], [0055], [0056]), with the dissolved oxygen concentration decreasing with altitude and permitting the fuel to absorb more heat without coking (see Figs. 4B & 4C), which would result in the fuel being able to absorb more heat without coking at cruise due to the altitude (Figs. 4B, 4C and at para. [0036]). The capability of absorbing more heat permits increased operational efficiency (para. [0002]).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the reference patent’s gas turbine engine to include a controller configured to control the heat exchange system based on the dissolved oxygen concentration of the fuel, as taught by Veilleux, in order to provide additional heat to the fuel during heating when the fuel is capable of absorbing the additional heat without coking (Veilleux; para. [0056]).
While the reference patent in view of Veilleux fails to expressly teach the temperature to which the fuel is heated at cruise, Veilleux clearly shows the fuel coking threshold increasing from 250°F to over 325° (121°C to 162°C), depending on dissolved oxygen, which overlaps the claimed range. Veilleux teaches that as the ability to increase the heat absorption of the fuel increases, operational efficiency increases (para. [0002]). Thus, the fuel temperature is found to be a result-effective variable which permits increasing operational efficiency while being bounded at an upper range in view of coking concerns.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the reference patent in view of Veilleux’s gas turbine engine such that the controller is configured to control the fuel management system to heat the fuel to at least 135°C on entry to the combustor at cruise conditions as a matter of routine optimization to determine the temperature range of the fuel which increases operational efficiency while avoiding coking. There was a reasonable expectation of success in view of Veilleux’s teaching of fuel coking temperatures increasing beyond 162°C, which would permit the fuel to be heated to some margin just below that while avoiding coking. A particular parameter must first be recognized as a result-effective variable, i.e., a variable which achieves a recognized result, before the determination of the optimum or workable ranges of said variable might be characterized as routine experimentation. See MPEP 2144.05 II(A). 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). See MPEP 2144.05 II(B).
Response to Arguments
Applicant’s arguments with respect to all claims have been considered but are moot in view of the new grounds of rejection set forth above under 35 U.S.C. 103.
Conclusion
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
Contact Information
Any inquiry concerning this communication or earlier communications from the examiner should be directed to SCOTT J WALTHOUR whose telephone number is (571)272-4999. The examiner can normally be reached Monday-Friday, 10 a.m.-6 p.m. Eastern.
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/SCOTT J WALTHOUR/ Primary Examiner, Art Unit 3741
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