Prosecution Insights
Last updated: April 19, 2026
Application No. 19/065,009

HYDROGEN TURBINE POWER ASSISTED CONDENSATION

Non-Final OA §103
Filed
Feb 27, 2025
Examiner
MEILLER, SEAN V
Art Unit
3741
Tech Center
3700 — Mechanical Engineering & Manufacturing
Assignee
Rtx Corporation
OA Round
3 (Non-Final)
77%
Grant Probability
Favorable
3-4
OA Rounds
2y 6m
To Grant
99%
With Interview

Examiner Intelligence

Grants 77% — above average
77%
Career Allow Rate
98 granted / 127 resolved
+7.2% vs TC avg
Strong +36% interview lift
Without
With
+35.8%
Interview Lift
resolved cases with interview
Typical timeline
2y 6m
Avg Prosecution
37 currently pending
Career history
164
Total Applications
across all art units

Statute-Specific Performance

§101
0.3%
-39.7% vs TC avg
§103
55.9%
+15.9% vs TC avg
§102
23.5%
-16.5% vs TC avg
§112
18.8%
-21.2% vs TC avg
Black line = Tech Center average estimate • Based on career data from 127 resolved cases

Office Action

§103
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and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114.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 12/17/2025 has been entered. 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 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. Claims 1-3, 5, 13-17, and 20 are rejected under 35 U.S.C. 103 as being unpatentable over Klingels (US-Pub 2021/0207500) in view of Snyder (10968830), Suciu (9850819), and Nebgen (3788066), as evidenced by Kurzke (NPL, see attached documents for relevant pages) Regarding claim 1, Klingels discloses an aircraft engine (1, fig 1), comprising: a core assembly (2, fig 1) comprising a fan section, a compressor section, a burner section, and a turbine section arranged along a shaft (fig 2, these are all basic parts of a gas turbine as shown in the figure), with a core flow path (path within the main body of the turbine, fig 1) directed from the fan section, through the compressor section, the burner section, and the turbine section such that exhaust from the burner section passes through the turbine section, the core assembly further comprising a bypass duct (duct that flows around the gas turbine engine core, fig 1) configured to extend from the fan section and bypass the compressor section, the burner section, and the turbine section; a core condenser (8, fig 1) arranged downstream of the turbine section of the core assembly along the core flow path, the core condenser configured to condense water from the core flow path; and an open-loop refrigeration system (7 to 14, fig 1). Klingels does not disclose a refrigeration heat exchanger arranged within the bypass duct and a refrigeration turbine configured to receive a cold stream flow from the refrigeration heat exchanger to expand the cold stream flow and to direct the expanded cold stream flow into thermal interaction with a core flow passing through the core condenser and wherein the open-loop refrigeration system is configured to control a delta temperature at which heat exchange occurs between the core flow and the cold stream flow, a first temperature sensor arranged to monitor a first temperature of the core condenser; a second temperature sensor arranged to monitor a second temperature of the cold stream flow path; and a controller in communication with the first and second temperature sensors and configured to monitor a delta temperature between the core condenser and the cold stream flow path, wherein the cold stream flow has a temperature of about 120F and the core flow has a temperature of 120F or greater. Snyder teaches an open-loop refrigeration system (88, fig 5) for a gas turbine with a refrigeration heat exchanger (122, fig 5) and a refrigeration turbine (124, fig 5) configured to receive a cold stream flow from the refrigeration heat exchanger to expand the cold stream flow and to direct the expanded cold stream flow into thermal interaction with a core flow (when combined with Klingels, the condenser 130 would be the core flow condenser, fig 5) and wherein the open-loop refrigeration system is configured to control a delta temperature at which heat exchange occurs between the core flow and the stream flow (based on bleed selection between 101 and 103 the temperature would change, and since this is an apparatus claim the system must merely be capable of performing the claimed function, which it is due to the different input options). It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the condenser air injection system disclosed by Klingels by using the open-loop air system with a refrigeration heat exchanger and refrigeration turbine along with an ambient air flow based on the teachings of Snyder. Doing so would allow for bleed air to be selected over ambient during flight regimes such as takeoff when ambient air temperatures may be too high (col 7, lines 27-55), as suggested by Snyder. Suciu teaches a cooling system of a gas turbine (20, fig 1) which places a refrigeration heat exchanger (84, fig 1) for a bleed flow (80, fig 1) within the bypass duct (B, fig 1) of the gas turbine. It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified refrigeration heat exchanger disclosed by Klingels as modified by Snyder by placing the heat exchanger in the bypass duct based on the teachings of Suciu. One of ordinary skill in the art would recognize that the bypass duct is the coolest area in the engine, so placing a heat exchanger there would provide passive cooling from the bypass flow. Nebgen discloses a refrigeration system for a gas turbine engine (fig 3), wherein the refrigerator evaporator (61, fig 3, which would map to the core condenser of Klingels), wherein the refrigerator evaporator (core condenser) has a first temperature sensor (69, fig 3) arranged to measure the ambient air (the ambient air is used as the cold stream flow path of both Nebgen and Woodhouse) and second temperature sensor (70, fig 3) arranged to monitor a temperature of the evaporator, and a controller (73, fig 3) configured to monitor a delta temperature between the first and second temperatures and maintain the temperature differential (col 10, lines 27-56) of at least 50 degrees (col 9, lines 63-67). It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the refrigeration system control system disclosed by Klingels as modified by Snyder by using a temperature sensor on the core condenser, and then using a controller to monitor and set the refrigeration system delta temperature using the temperature sensors on the cold stream flow path and the core condenser (modification by Nebgen) based on the teachings of Nebgen. Doing so would allow the control of the temperature differential so that freezing can be avoided (col 2, lines 10-20), as suggested by Nebgen. Kurzke page 180 and 181 shows standard temperature and pressure for different points along a gas turbine engine in Table 4.2-3 and fig 4.2-14, where, at ambient temperature of 288.15K, the bypass temperature (13) is 338.15K (148F) and the core temperature (8) is 861.63K (1091.26F). However, as per page 618, this is determined based upon the ambient temperature of 288.15 degrees at ground level, in flight, the temperature at ambient would be lower, and thus the temperature of the air in the bypass and the core would be lower by an equivalent number of degrees. This means, that in order for the bypass temperature to be about 120F, (322F), an ambient temperature of 30F (272K) would be required, which, according to the standard ISA day, would take place at approximately 4km of altitude, and would lead to a core temperature of 1061F (845K). Which means, during operation of the gas turbine of Klingels within the right flight conditions, the cold stream would have a temperature of about 120F (about being a range of plus or minus 8% in par. 0078.) and the core would have a temperature of 120F or greater. Regarding claim 2, Klingels as modified by Snyder in claim 1 discloses wherein a bleed air (101, 103, fig 5, Snyder) flow from the core assembly is extracted from the core flow and directed into the refrigeration heat exchanger to generate the cold stream flow. Regarding claim 3, Klingels as modified by Snyder in claim 1 discloses wherein the bleed air flow is extracted from a high-pressure compressor (103, fig 5) of the compressor section of the core assembly. Regarding claim 5, Klingels as modified by Snyder in claim 1 discloses a power source (128, fig 5, Snyder) configured to power operation of the refrigeration turbine. Regarding claim 13, Klingels discloses a water line (line from 15 to the turbine combustor 3, fig 1) fluidly connecting an output of the condensed water from the core condenser to the combustor section. Regarding claim 14, Klingels discloses a water tank (17, fig 1) arranged along the water line and configured to collect the condensed water. Regarding claim 15, Klingels discloses a water pump (18, fig 1) arranged along the water line and configured to pump the condensed water along the water line. Regarding claim 16, Klingels discloses a core flow evaporator (5, fig 1) arranged to thermally connect the core flow path and the water line, the core flow evaporator configured to increase a temperature of the condensed water. Regarding claim 17, Klingels discloses wherein the core flow evaporator is configured to convert the condensed water received from the core condenser to steam (Klingels, par. 0036). Regarding claim 20, Klingels discloses an aircraft engine (1, fig 1), comprising: a core assembly (2, fig 1) comprising a fan section, a compressor section, a burner section, and a turbine section arranged along a shaft (fig 2, these are all basic parts of a gas turbine as shown in the figure), with a core flow path (path within the main body of the turbine, fig 1) directed from the fan section, through the compressor section, the burner section, and the turbine section such that exhaust from the burner section passes through the turbine section, and a bypass duct (duct that flows around the gas turbine engine core, fig 1) configured to extend from the fan section and bypass the compressor section, the burner section, and the turbine section; a core condenser (8, fig 1) arranged downstream of the turbine section of the core assembly along the core flow path, the core condenser configured to condense water from the core flow path; and an open-loop refrigeration system (7 to 14, fig 1). Klingels does not disclose a refrigeration heat exchanger arranged within the bypass duct and a refrigeration turbine configured to receive a cold stream flow from the refrigeration heat exchanger to expand the cold stream flow and to direct the expanded cold stream flow into thermal interaction with a core flow passing through the core condenser and wherein the open-loop refrigeration system is configured to control a delta temperature at which heat exchange occurs between the core flow and the cold stream flow, wherein the cold stream flow is defined within a first cold stream flow path and a second cold stream flow path, wherein the first cold stream flow path is directed through the refrigeration heat exchanger and the second cold stream flow path is directed through the refrigeration system core condenser, a first temperature sensor arranged to monitor a first temperature of the core condenser; a second temperature sensor arranged to monitor a second temperature of the cold stream flow path; and a controller in communication with the first and second temperature sensors and configured to monitor a delta temperature between the core condenser and the cold stream flow path, wherein the cold stream flow has a temperature of about 120F and the core flow has a temperature of 120F or greater. Snyder teaches an open-loop refrigeration system (88, fig 5) for a gas turbine with a refrigeration heat exchanger (122, fig 5) and a refrigeration turbine (124, fig 5) configured to receive a cold stream flow from the refrigeration heat exchanger to expand the cold stream flow and to direct the expanded cold stream flow into thermal interaction with a core flow passing through the core condenser (the condenser of Klingels), and a refrigeration system core condenser (130, fig 5) thermally coupling the core flow and the cold stream flow, wherein the cold stream flow is defined within a first cold stream flow path (101 to 122, fig 5) and a second cold stream flow path (A, fig 4), wherein the first cold stream flow path is directed through the refrigeration heat exchanger and the second cold stream flow path is directed through the refrigeration system core condenser. It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the condenser air injection system disclosed by Klingels by using the open-loop air system with a refrigeration heat exchanger and refrigeration turbine along with an ambient air flow based on the teachings of Snyder. Doing so would allow for bleed air to be selected over ambient during flight regimes such as takeoff when ambient air temperatures may be too high (col 7, lines 27-55), as suggested by Snyder. Suciu teaches a cooling system of a gas turbine (20, fig 1) which places a refrigeration heat exchanger (84, fig 1) for a bleed flow (80, fig 1) within the bypass duct (B, fig 1) of the gas turbine. It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified refrigeration heat exchanger disclosed by Klingels as modified by Snyder by placing the heat exchanger in the bypass duct based on the teachings of Suciu. One of ordinary skill in the art would recognize that the bypass duct is the coolest area in the engine, so placing a heat exchanger there would provide passive cooling from the bypass flow. Nebgen discloses a refrigeration system for a gas turbine engine (fig 3), wherein the refrigerator evaporator (61, fig 3, which would map to the core condenser of Klingels), wherein the refrigerator evaporator (core condenser) has a first temperature sensor (69, fig 3) arranged to measure the ambient air (the ambient air is used as the cold stream flow path of both Nebgen and Woodhouse) and second temperature sensor (70, fig 3) arranged to monitor a temperature of the evaporator, and a controller (73, fig 3) configured to monitor a delta temperature between the first and second temperatures and maintain the temperature differential (col 10, lines 27-56) of at least 50 degrees (col 9, lines 63-67). It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the refrigeration system control system disclosed by Klingels as modified by Snyder by using a temperature sensor on the core condenser, and then using a controller to monitor and set the refrigeration system delta temperature using the temperature sensors on the cold stream flow path and the core condenser (modification by Nebgen) based on the teachings of Nebgen. Doing so would allow the control of the temperature differential so that freezing can be avoided (col 2, lines 10-20), as suggested by Nebgen. Kurzke page 180 and 181 shows standard temperature and pressure for different points along a gas turbine engine in Table 4.2-3 and fig 4.2-14, where, at ambient temperature of 288.15K, the bypass temperature (13) is 338.15K (148F) and the core temperature (8) is 861.63K (1091.26F). However, as per page 618, this is determined based upon the ambient temperature of 288.15 degrees at ground level, in flight, the temperature at ambient would be lower, and thus the temperature of the air in the bypass and the core would be lower by an equivalent number of degrees. This means, that in order for the bypass temperature to be about 120F, (322F), an ambient temperature of 30F (272K) would be required, which, according to the standard ISA day, would take place at approximately 4km of altitude, and would lead to a core temperature of 1061F (845K). Which means, during operation of the gas turbine of Klingels within the right flight conditions, the cold stream would have a temperature of about 120F and the core would have a temperature of 120F or greater. Claim 19 is rejected under 35 U.S.C. 103 as being unpatentable over Klingels in view of Snyder, Suciu, Nebgen, and Finney (US-Pub 2013/0040545) as evidenced by Kurzke. Regarding claim 19, Klingels discloses an aircraft engine (1, fig 1), comprising: a core assembly (2, fig 1) comprising a fan section, a compressor section, a burner section, and a turbine section arranged along a shaft (fig 2, these are all basic parts of a gas turbine as shown in the figure), with a core flow path (path within the main body of the turbine, fig 1) directed from the fan section, through the compressor section, the burner section, and the turbine section such that exhaust from the burner section passes through the turbine section, and a bypass duct (duct that flows around the gas turbine engine core, fig 1) configured to extend from the fan section and bypass the compressor section, the burner section, and the turbine section; a core condenser (8, fig 1) arranged downstream of the turbine section of the core assembly along the core flow path, the core condenser configured to condense water from the core flow path; and an open-loop refrigeration system (7 to 14, fig 1). Klingels does not disclose a refrigeration heat exchanger arranged within the bypass duct and a refrigeration turbine configured to receive a cold stream flow from the refrigeration heat exchanger to expand the cold stream flow and to direct the expanded cold stream flow into thermal interaction with a core flow passing through the core condenser and wherein the open-loop refrigeration system is configured to control a delta temperature at which heat exchange occurs between the core flow and the cold stream flow, and a refrigeration compressor arranged between a bleed extraction point on the core assembly and the refrigeration heat exchanger, the refrigeration compressor configured to increase a pressure of the bleed air flow, a first temperature sensor arranged to monitor a first temperature of the core condenser; a second temperature sensor arranged to monitor a second temperature of the cold stream flow path; and a controller in communication with the first and second temperature sensors and configured to monitor a delta temperature between the core condenser and the cold stream flow path, wherein the cold stream flow has a temperature of about 120F and the core flow has a temperature of 120F or greater. Snyder teaches an open-loop refrigeration system (88, fig 5) for a gas turbine with a refrigeration heat exchanger (122, fig 5) and a refrigeration turbine (124, fig 5) configured to receive a cold stream flow from the refrigeration heat exchanger to expand the cold stream flow and to direct the expanded cold stream flow into thermal interaction with a core flow (when combined with Klingels, the condenser 130 would be the core flow condenser, fig 5) passing through the core condenser (130, fig 5). It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the condenser air injection system disclosed by Klingels by using the open-loop air system with a refrigeration heat exchanger and refrigeration turbine along with an ambient air flow based on the teachings of Snyder. Doing so would allow for bleed air to be selected over ambient during flight regimes such as takeoff when ambient air temperatures may be too high (col 7, lines 27-55), as suggested by Snyder. Suciu teaches a cooling system of a gas turbine (20, fig 1) which places a refrigeration heat exchanger (84, fig 1) for a bleed flow (80, fig 1) within the bypass duct (B, fig 1) of the gas turbine. It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified refrigeration heat exchanger disclosed by Klingels as modified by Snyder by placing the heat exchanger in the bypass duct based on the teachings of Suciu. One of ordinary skill in the art would recognize that the bypass duct is the coolest area in the engine, so placing a heat exchanger there would provide passive cooling from the bypass flow. Finney teaches a refrigeration system (38, fig 1) for a gas turbine wherein the refrigeration system further comprises a refrigeration compressor (50, fig 1) arranged between a bleed extraction point (44, fig 1) on the core assembly (10, fig 1) and the refrigeration heat exchanger (38, fig 1), the refrigeration compressor configured to increase a pressure of the bleed air flow (this is what a compressor does). It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the bleed line disclosed by Klingels as modified by Snyder by having a compressor to increase the bleed air pressure before going to the heat exchanger based on the teachings of Finney. Doing so would allow for the system to function while the compressor pressure is too low (par. 0005), as suggested by Finney. Nebgen discloses a refrigeration system for a gas turbine engine (fig 3), wherein the refrigerator evaporator (61, fig 3, which would map to the core condenser of Klingels), wherein the refrigerator evaporator (core condenser) has a first temperature sensor (69, fig 3) arranged to measure the ambient air (the ambient air is used as the cold stream flow path of both Nebgen and Woodhouse) and second temperature sensor (70, fig 3) arranged to monitor a temperature of the evaporator, and a controller (73, fig 3) configured to monitor a delta temperature between the first and second temperatures and maintain the temperature differential (col 10, lines 27-56) of at least 50 degrees (col 9, lines 63-67). It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the refrigeration system control system disclosed by Klingels as modified by Snyder by using a temperature sensor on the core condenser, and then using a controller to monitor and set the refrigeration system delta temperature using the temperature sensors on the cold stream flow path and the core condenser (modification by Nebgen) based on the teachings of Nebgen. Doing so would allow the control of the temperature differential so that freezing can be avoided (col 2, lines 10-20), as suggested by Nebgen. Kurzke page 180 and 181 shows standard temperature and pressure for different points along a gas turbine engine in Table 4.2-3 and fig 4.2-14, where, at ambient temperature of 288.15K, the bypass temperature (13) is 338.15K (148F) and the core temperature (8) is 861.63K (1091.26F). However, as per page 618, this is determined based upon the ambient temperature of 288.15 degrees at ground level, in flight, the temperature at ambient would be lower, and thus the temperature of the air in the bypass and the core would be lower by an equivalent number of degrees. This means, that in order for the bypass temperature to be about 120F, (322F), an ambient temperature of 30F (272K) would be required, which, according to the standard ISA day, would take place at approximately 4km of altitude, and would lead to a core temperature of 1061F (845K). Which means, during operation of the gas turbine of Klingels within the right flight conditions, the cold stream would have a temperature of about 120F and the core would have a temperature of 120F or greater. Claim 4 is rejected under 35 U.S.C. 103 as being unpatentable over Klingels in view of Snyder, Suciu as applied to claim 2 above, and further in view of Finney. Regarding claim 4, Klingels as modified by Snyder in claim 1 does not disclose wherein the open-loop refrigeration system further comprises a refrigeration compressor arranged between a bleed extraction point on the core assembly and the refrigeration heat exchanger, the refrigeration compressor configured to increase a pressure of the bleed air flow. Finney teaches a refrigeration system (38, fig 1) for a gas turbine wherein the refrigeration system further comprises a refrigeration compressor (50, fig 1) arranged between a bleed extraction point (44, fig 1) on the core assembly (10, fig 1) and the refrigeration heat exchanger (38, fig 1), the refrigeration compressor configured to increase a pressure of the bleed air flow (this is what a compressor does). It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the bleed line disclosed by Klingels as modified by Snyder by having a compressor to increase the bleed air pressure before going to the heat exchanger based on the teachings of Finney. Doing so would allow for the system to function while the compressor pressure is too low (par. 0005), as suggested by Finney. Claims 6-10 are rejected under 35 U.S.C. 103 as being unpatentable over Klingels in view of Snyder, Suciu as applied to claim 1 above, and further in view of Schroder (1653603). Regarding claim 6, Klingels discloses a refrigeration system core condenser (8, fig 1), thermally coupling the core flow and the cold stream flow. Klingels as modified by Snyder in claim 1 does not disclose wherein the open-loop refrigeration system further comprises a refrigeration system core condenser thermally coupling the core flow and the cold stream flow, wherein the refrigeration system core condenser is arranged upstream from the core condenser along the core flow path. Schroder teaches an exhaust gas water recovery system, wherein instead of a single condenser (107, fig 4), two condensers (207 and 201, fig 6) are used. It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the bleed line disclosed by Klingels as modified by Snyder by using the condenser of Klingels as a first condenser and the condenser of Schroder as a second condenser based on the teachings of Schroder. One of ordinary skill in the art would recognize that multiple condensers can increase efficiency by allowing for each individual condenser to operate at a more efficient temperature range. Regarding claim 7, Klingels discloses a refrigeration system core condenser (8, fig 1), thermally coupling the core flow and the cold stream flow. Klingels as modified by Snyder in claim 1 wherein the cold stream flow is defined within a first cold stream flow path and a second cold stream flow path, wherein the first cold stream flow path is directed through the refrigeration heat exchanger and the second cold stream flow path is directed through the refrigeration system core condenser. Schroder teaches an exhaust gas water recovery system, wherein instead of a single condenser (107, fig 4), two condensers (207 and 201, fig 6) are used, wherein a cold stream flow is defined within a first cold stream flow path (wind to 210, fig 6) and a second cold stream flow path (206, fig 6), wherein the first cold stream flow path is directed through the refrigeration heat exchanger (207, fig 6) and the second cold stream flow path is directed through the refrigeration system core condenser (201, fig 6). It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the bleed line disclosed by Klingels as modified by Snyder by using the condenser of Klingels as a first condenser and the condenser of Schroder as a second condenser based on the teachings of Schroder. One of ordinary skill in the art would recognize that multiple condensers can increase efficiency by allowing for each individual condenser to operate at a more efficient temperature range. Regarding claim 8, Klingels as modified by Snyder and Schroder discloses wherein the first cold stream flow path and the second cold stream flow path are sourced from a single cold stream source (Klingels receives air from an ambient source to inlet (7, fig 1, Klingels), Snyder can receive air from an ambient source (D, fig 4, Snyder), thus meaning that they receive air from the same source). Regarding claim 9, Klingels as modified by Snyder and Schroder discloses wherein the first cold stream flow path is sourced from a first cold stream source and the second cold stream flow path is sourced from a second cold stream source (Klingels can air from an ambient source to inlet (20, fig 1, Klingels), Snyder can receive air from a fan source (A, fig 4, Snyder), thus meaning that they receive air Different sources). Regarding claim 10, Klingels as modified by Snyder and Schroder discloses wherein the first cold stream source is the fan section (Snyder, col 4, lines 45-50, the cold streams for cooling can be sourced from a fan section or a ram inlet) of the core assembly and the second cold stream source is a ram inlet (20, fig 1, the open air would serve as a ram inlet into the condenser). Claim 18 is rejected under 35 U.S.C. 103 as being unpatentable over Klingels in view of Snyder, Suciu as applied to claim 1 above, and further in view of Hagen (4063184). Regarding claim 18, Klingels does not disclose a cryogenic fuel tank configured to supply cryogenic fuel along a fuel line to the burner section for combustion. Hagen teaches a gas turbine engine (2, fig 1) which uses a cryogenic fuel tank (10, fig 1) to supply cryogenic fuel along a fuel line to the burner section. It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the gas turbine engine disclosed by Klingels as modified by Snyder by using a cryogenic fuel tank to supply a cryogenic fuel instead of conventional hydrogen fuel based on the teachings of Hagen. One of ordinary skill in the art would recognize that cryogenic fuel is a known gas turbine fuel that provides a higher mass flow rate than fossil fuels. Response to Arguments Applicant's arguments filed 12/04/2025 have been fully considered but they are not persuasive. Applicant argues that Klingels as modified does not disclose the claimed temperature ranges of about 120 for a cold stream flow and greater than 120 for a core flow. This argument is not persuasive because as evidenced by Kurzke above, Klingels as modified would operate within the claimed temperature ranges. Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to SEAN V MEILLER whose telephone number is (571)272-9229. The examiner can normally be reached 7am-5pm. Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice. If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Devon Kramer can be reached at 571-272-7118. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300. Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000. /SEAN V MEILLER/Examiner, Art Unit 3741 /DEVON C KRAMER/Supervisory Patent Examiner, Art Unit 3741
Read full office action

Prosecution Timeline

Feb 27, 2025
Application Filed
Jun 12, 2025
Non-Final Rejection — §103
Sep 16, 2025
Response Filed
Oct 09, 2025
Final Rejection — §103
Dec 04, 2025
Response after Non-Final Action
Dec 17, 2025
Request for Continued Examination
Jan 06, 2026
Response after Non-Final Action
Jan 21, 2026
Non-Final Rejection — §103 (current)

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Prosecution Projections

3-4
Expected OA Rounds
77%
Grant Probability
99%
With Interview (+35.8%)
2y 6m
Median Time to Grant
High
PTA Risk
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