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 .
Claim Objections
Claims 1, 15, and 20 objected to because of the following informalities:
Claims 1 and 15: lines 5 and 6, “the combustor” should read “the combustor section” to better align with its antecedent.
Claim 1, line 3 reads “a hydrogen based fuel”, while line 5 reads “hydrogen fuel” when referring to the same object, these should both read hydrogen based fuel to enhance clarity.
Claim 20: line 6, “propulsor” should read “a propulsor”. Appropriate correction is required.
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis 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, 4, 10, 11, and 15 are rejected under 35 U.S.C. 103 as being unpatentable over Klingels (US-Pub 2021/0207500) in view of Nielsen (5797259), Hagen (4062184), and Scipio (US-Pub 2014/0137564).
Regarding claim 1, Klingels discloses a propulsion system for an aircraft (1, fig 3) comprising: a core engine (2, fig 1) including a core flow path where air is compressed in a compressor section (23, fig 3), communicated to a combustor section (3, fig 3), mixed with a fuel and ignited to generate an exhaust gas flow that is expanded through a turbine section (24, fig 3); a condenser (8, fig 3) arranged along the core flow path and configured to extract water from the exhaust gas flow; an evaporator (5, fig 3) arranged along the core flow path and configured to receive a portion of the water (from 17, fig 3) extracted by the condenser to generate a first steam flow (par. 0015), and a steam turbine (6, fig 3) where the first steam flow is expanded to generate shaft power.
Klingels does not disclose a hydrogen fuel system configured to supply hydrogen fuel to the combustor through a fuel flow path to mix the air with a hydrogen based fuel, or a cooled cooling air system configured to use water extracted from the exhaust gas flow for cooling a cooling airflow communicated to the turbine section, wherein the cooled cooling air system includes a cooling evaporator in thermal communication with the cooling airflow for cooling the cooling airflow before the cooling airflow is injected into the turbine section and for generating a second steam flow that is combined with the steam flow generated in the evaporator and injected into the steam turbine, and a steam injection location upstream of the combustor section where steam flow from the steam turbine is injected into the core flow path before the combustion section.
Nielsen teaches a gas turbine engine (fig 6, whole figure), which uses a cooled cooling air system (11, 10, and 13, fig 6) configured to use water (18, fig 6) for cooling a cooling airflow (in 11, fig 6) communicated to the turbine section (3, fig 6), wherein the cooled cooling air system includes a cooling evaporator (10, fig 6) in thermal communication with the cooling airflow for cooling the cooling airflow before the cooling airflow is injected into the turbine section and for generating a second steam flow (14, fig 6) that is combined with the steam flow generated in the evaporator (15, fig 6) where the combined first and second steam flow are expanded in a steam turbine (17, fig 6) to generate shaft power.
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 steam cooling system disclosed by Klingels by using the water extracted to cool the cooling airflow communicated with the turbine system and then combining the steam generated with the steam flow from the evaporator before being used in a steam turbine based on the teachings of Nielsen. Doing so would allow the cooling air to be cooled while still having the waste heat available for use in the system (col 1, lines 13-38).
Hagen teaches a gas turbine engine (1, fig 1) using a hydrogen fuel system (10, fig 1) configured to supply hydrogen fuel to a combustor (23, fig 1) through a fuel flow path (11, fig 1) to mix the air with a hydrogen based fuel.
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 fuel system disclosed by Klingels as modified by Nielsen by using hydrogen as a fuel source based on the teachings of Hagen. Hydrogen is a known fuel source for gas turbines (col 1, lines 2-14), as suggested by Hagen.
Scipio teaches a system for injecting steam into a gas turbine which comprises a steam injection location (14, fig 1) upstream of the combustor section where steam flow from the steam source (which, when combined with Klingels, would be the steam turbine) is injected into the core flow path before the combustor 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 steam injection system disclosed by Klingels by having a steam injector upstream of the combustor section based on the teachings of Scipio. Doing so would reduce combustor oscillations (par. 0035), which is known to improve engine efficiency, as suggested by Scipio.
Regarding claim 4, Klingels discloses including a boost pump (18, fig 3) for increasing a pressure of water provided to the cooling evaporator.
Regarding claim 10, Klingels as modified by Nielson discloses a water storage tank (17, fig 3) and the condenser communicates water to the water storage tank and a first pump (18, fig 3) is configured to move water from the storage tank to the cooled cooling air system(10, 11, 13, fig 6, Nielson).
Regarding claim 11, Klingels discloses wherein the turbine section includes a low pressure turbine configured to drive a fan through a low shaft (fig 3, there is a low pressure turbine and a high pressure turbine with a low compressor and a high compressor, the fan connected to the low pressure turbine).
Regarding claim 15, Klingels discloses a propulsion system for an aircraft (1, fig 3) comprising: a core engine (2, fig 3) including a core flow path where air is compressed in a compressor section (23, fig 3), communicated to a combustor section (3, fig 3), mixed with a fuel and ignited to generate an exhaust gas flow that is expanded through a turbine section (24, fig 3), wherein the compressor section includes a low pressure compressor upstream of a high pressure compressor (23, fig 3, the compressor includes a low and high pressure compressor); a condenser (8, fig 3) arranged along the core flow path and configured to extract water from the exhaust gas flow; an evaporator (5, fig 3) arranged along the core flow path and configured to receive a portion of the water (from 17, fig 3) extracted by the condenser to generate a steam flow (par. 0015), wherein the steam flow is injected into the core flow path (fig 3, it is injected into the combustor which is upstream of the turbine).
Klingels does not disclose wherein the air is mixed with a hydrogen fuel; a hydrogen fuel system configured to supply hydrogen fuel to the combustor through a fuel flow path, or at least one tap in compressor section communicating a cooling airflow to the turbine section; and a heat transfer device configured to place the cooling airflow into thermal communication with a water flow extracted from the exhaust gas flow from the condenser, wherein the heat transfer device comprises a cooling evaporator in thermal communication with the cooling airflow for cooling the cooling airflow before the cooling airflow is injected into the turbine section and for generating a second steam flow that is combined with the steam flow generated in the evaporator and injected into the steam turbine, and a steam injection location upstream of the combustor section where steam flow from the steam turbine is injected into the core flow path before the combustion section.
Nielsen teaches a gas turbine engine (fig 6, whole figure), which uses a tap in the compressor section to provide air to a cooled cooling air system (11, 10, and 13, fig 6) configured to use water (18, fig 6) for cooling a cooling airflow (in 11, fig 6) communicated to the turbine section (3, fig 6), wherein the cooled cooling air system includes a cooling evaporator (10, fig 6) in thermal communication with the cooling airflow for cooling the cooling airflow before the cooling airflow is injected into the turbine section and for generating a second steam flow (14, fig 6) that is combined with the steam flow generated in the evaporator (15, fig 6) before being injected into a steam turbine (17, fig 6) as a combined first and second steam flow.
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 steam cooling system disclosed by Klingels by using the water extracted to cool the cooling airflow communicated with the turbine system and then combining the steam generated with the steam flow from the evaporator before being used in a steam turbine based on the teachings of Nielsen. Doing so would allow the cooling air to be cooled while still having the waste heat available for use in the system (col 1, lines 13-38).
Hagen teaches a gas turbine engine (1, fig 1) using a hydrogen fuel system (10, fig 1) configured to supply hydrogen fuel to a combustor (23, fig 1) through a fuel flow path (11, fig 1) to mix the air with a hydrogen based fuel.
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 fuel system disclosed by Klingels as modified by Nielsen by using hydrogen as a fuel source based on the teachings of Hagen. Hydrogen is a known fuel source for gas turbines (col 1, lines 2-14), as suggested by Hagen.
Scipio teaches a system for injecting steam into a gas turbine which comprises a steam injection location (14, fig 1) upstream of the combustor section where steam flow from the steam source (which, when combined with Klingels, would be the steam turbine) is injected into the core flow path before the combustor 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 steam injection system disclosed by Klingels by having a steam injector upstream of the combustor section based on the teachings of Scipio. Doing so would reduce combustor oscillations (par. 0035), which is known to improve engine efficiency, as suggested by Scipio.
Claim 8 is rejected under 35 U.S.C. 103 as being unpatentable over Klingels as modified by Nielsen and Hagen and Scipio as applied to claims 1 above, and further in view of Reynolds (6293086).
Klingels as modified by Nielsen and Hagen and Scipio does not disclose an intercooling system, configured to inject water into the compressor section of a turbine engine upstream of a steam injection system.
Reynolds teaches an intercooling system (23, fig 2), configured to inject water into the compressor section (11 and 12, fig 2) of a turbine engine (35, fig 2) upstream of a steam injection system (24, fig 2).
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 steam injection system disclosed by Klingels by using an intercooling system to inject water into the compressor section upstream of the combustor section based on the teachings of Reynolds. Doing so would reduce the temperature of the water before flowing into the first and second compressor (col 2, lines 35-49), which is known to improve engine efficiency, as suggested by Reynolds.
Claims 12-14 and 20 are rejected under 35 U.S.C. 103 as being unpatentable over Klingels as modified by Nielsen and Hagen and Scipio as applied to claims 1 and 15 above, and further in view of McCaffrey (8943796).
Regarding claim 12, Klingels discloses wherein the turbine section includes a low pressure turbine and a high pressure turbine (24, fig 3 contains a low pressure and high pressure turbine) and the compressor section includes a high pressure compressor coupled to the high pressure turbine through a high shaft (23 contains a high pressure compressor coupled to the high pressure turbine through a high shaft, fig 3).
Klingels as modified by Nielsen, Hagen, and Scipio does not disclose and an intermediate pressure turbine and a low pressure compressor coupled to the intermediate pressure turbine through an intermediate shaft.
McCaffrey teaches a gas turbine including an intermediate pressure turbine (34, fig 1) and a low pressure compressor (32, fig 1, although it is called the intermediate compressor, it is the lowest pressure compressor before the fans and is connected to the same turbine as applicants’ invention, thus it provides the same function as the low pressure compressor) coupled to the intermediate pressure turbine through an intermediate shaft (36, fig 1).
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 two spool engine disclosed by Klingels as modified by Nielsen, Hagen, and Scipio by using a three spooled architecture with the intermediate spool connected to an intermediate turbine and low pressure compressor based on the teachings of McCaffrey. One of ordinary skill in the art would recognize that higher compression ratios can be achieved with three spool engines.
Regarding claim 13, Klingels discloses wherein the steam turbine is coupled a low shaft (fig 3, the steam turbine is connected to the low pressure shaft).
Regarding claim 14, Klingels as modified by Nielsen, Hagen, and Scipio does not disclose including a gearbox coupled to the low shaft for driving a fan at a speed lower than the low pressure turbine.
McCaffrey teaches a gas turbine engine (10, fig 1) which has a gearbox (28, fig 1) coupled to the low shaft for driving a fan at a lower speed than the low pressure turbine (the gearbox is a reduction gearbox, which is used to reduce the rotation rate).
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 two spool engine disclosed by Klingels as modified by Nielsen and Hagen by using a gearbox to drive the fan at a lower speed than the low pressure turbine based on the teachings of McCaffrey. One of ordinary skill in the art would recognize that if the fan spins too fast it can damage the much larger blades of the fan due to the higher tip speed.
Regarding claim 20, Klingels discloses wherein the turbine section includes a low pressure turbine and a high pressure turbine (24, fig 3, the turbine section has a low pressure and high pressure turbine), the compressor section includes a high pressure compressor coupled to the high pressure turbine through a high shaft (23, fig 1, there is a high shaft connecting the high pressure compressor to the high pressure turbine) and a low shaft is coupled to the low pressure turbine and propulsor (fig 3, the low pressure turbine connects to the fan via a low shaft).
Klingels as modified by Nielsen and Hagen does not disclose and an intermediate pressure turbine and a low pressure compressor coupled to the intermediate pressure turbine through an intermediate shaft.
McCaffrey teaches a gas turbine including an intermediate pressure turbine (34, fig 1) and a low pressure compressor (32, fig 1, although it is called the intermediate compressor, it is the lowest pressure compressor before the fans and is connected to the same turbine as applicants’ invention, thus it provides the same function as the low pressure compressor) coupled to the intermediate pressure turbine through an intermediate shaft (36, fig 1).
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 two spool engine disclosed by Klingels as modified by Nielsen and Hagen by using a three spooled architecture with the intermediate spool connected to an intermediate turbine and low pressure compressor based on the teachings of McCaffrey. One of ordinary skill in the art would recognize that higher compression ratios can be achieved with three spool engines.
Response to Arguments
Applicant’s arguments, see remarks, filed 4/2/2025, with respect to the claim objection of claim 15 have been fully considered and are persuasive. The objection of claim 15 has been withdrawn.
Applicant's arguments filed 9/15/2025 have been fully considered but they are not persuasive. Applicant argues that Scipio’s “steam source” cannot correspond to the steam from Klingels, as the steam from Klingels comes from an expansion turbine, and thus the pressures would be too low to inject into the compressor. This argument is not persuasive, as there is no explicit teaching from Scipio that the “steam source” cannot be the exhaust of a steam turbine. Further arguments that Scipio uses a non-expanded steam flow are not persuasive, as non-expanded is a relative term, for example, if Scipio used steam at a pressure of 35 atm, while the steam of Klingels was originally at 50 atm and expanded to 35 atm, the net result would be the same. Applicant further argues that compressor pressure is higher than combustor pressure, this is only true due to minor pressure losses, and thus one of ordinary skill in the art would recognize the steam of Klingels would be injected at a significantly higher pressure than the air in the combustor to prevent backflow and thus would still be able to be injected into the compressor as in Scipio, and further Scipio does teach that the same pressure steam can be injected into both the compressor and the combustor. Applicant further argues that the combination is improper as Scipio teaches injecting steam into both the combustor and compressor, and using that to modulate combustion dynamics, however, this does not run contrary to the modification, as the modification being made to Klingels is to add a steam injection site to the compressor, not to replace the steam injection site of Klingels.
Conclusion
THIS ACTION IS MADE FINAL. 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.
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
Prosecution Insights