CTNF 19/178,262 CTNF 90892 DETAILED ACTION 07-03-aia AIA 15-10-aia The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA. Claims 1-18 are currently pending in the application. Specification 07-29 AIA The disclosure is objected to because of the following informalities: The title of the invention is not descriptive. A new title is required that is clearly indicative of the invention to which the claims are directed. The following title is suggested: THERMAL MANAGEMENT SYSTEMS HAVING HEAT EXCHANGER WITH SOLID-SOLID PHASE CHANGE MATERIAL FOR GAS TURBINE ENGINES Appropriate correction is required. Claim Rejections - 35 USC § 103 07-20-aia AIA 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. 07-21-aia AIA Claim s 1, 3, 5-9, 12, 14, 16 are rejected under 35 U.S.C. 103 as being unpatentable over Appukuttan (US 2016/0281603 A1, cited in the 04/14/2025 Information Disclosure Statement), in view of Widstrom (US 2022/0025782 A1, cited in the 04/14/2025 Information Disclosure Statement), further in view of Thiagarajan (US 2016/0169591 A1) . Regarding independent claim 1 , Appukuttan discloses a thermal management system (Fig. 3) for a gas turbine engine (Fig. 1), comprising: an oil source 118 (“oil tank”, Fig. 3, Para. 0025); a pump 120 configured to generate a flow of oil from the oil source (Para. 0025); a first heat exchanger 130 downstream of the oil source (Fig. 3, Para. 0026 “ a further heat exchanger 130 ”); a second heat exchanger 108/122 downstream of the oil source (Fig. 3, either of the “ oil to fuel heat exchanger (FOHE) 108 ” or “ oil to air heat exchanger (AOHE) 122 ”, Para. 0024-25); and one or more thermal loads 18 (Para. 0027, “ engine components to be cooled, such as bearings ”) downstream of the first heat exchanger and the second heat exchanger (Fig. 3, Para. 0027, “ Once the oil flow has passed through the further heat exchanger, it is then passed downstream to an oil side of the FOHE 108 where it is cooled further, by transferring heat to the engine fuel. Oil is then recirculated through a return line 132 to engine components to be cooled, such as bearings, where the oil is again heated ”); wherein the first heat exchanger includes a phase change material (PCM, Para. 0026, “ The further heat exchanger 130 comprise a phase change material (PCM) located in heat exchange relationship with oil passing through the further heat exchanger 130 in use ”). Appukuttan fails to disclose wherein the first heat exchanger includes a solid-solid phase change material. Widstrom teaches an aircraft engine oil system (Fig. 1) for cooling a thermal load (bearings 6A-6D, Para. 0096), the system comprising a heat exchanger 7, wherein the system comprises oil conduits 11 having a phase change material 15 (Fig. 3B, Para. 0107), wherein the phase change material can include a solid-solid phase change material (Para. 0030, “ the material selected for the phase changing material may be any suitable material… Examples include but are not limited to organic and inorganic salts, inorganic eutectics, hydroscopic materials, hydrated salts, organic solutions and solid-solid materials ”). Thiagarajan teaches a heat exchanger 200 (Fig. 3-4) for an aircraft system that includes a phase change material 150 (Para. 0019-22), that can be a solid-solid phase change material (Para. 0029-31) which is described as being able to absorb heat without increasing the temperature of the system, undergoing reversible solid-state crystal structure transitions at certain temperatures; wherein the type of phase change material is selected based on the desired transition temperatures and amount of heat that is desired to be absorbed, with solid-solid phase change materials having a transition temperature over a “ limited temperature range ” (Thiagarajan Para. 0029-31). It has been held to be within the general skill of a worker in the art to select a known material on the basis of its suitability for the intended use as a matter of obvious design choice. In re Leshin , 277 F.2d 197, 125 USPQ 416 (CCPA 1960). See MPEP 2144.07. Therefore it would have been obvious to one of ordinary skill in the art at the time the invention was filed to have modified the system of Appukuttan such that the first heat exchanger’s phase change material is a solid-solid phase change material, such as a material taught in Widstrom and Thiagarajan, in order to provide a phase change material having desired properties such as a desired transition temperature range, and heat absorption capacity (Widstrom Para. 0030; Thiagarajan Para. 0029-31). Appukuttan already discloses the first heat exchanger 130 utilizing a phase change material, and one skilled in the art would know to select from known materials in the art (including solid-solid phase change materials), on the basis of their suitability for the intended use of the system, to achieve a desired level of performance. Regarding claim 3 , Appukuttan in view of Widstrom & Thiagarajan teaches the thermal management system of claim 1, but fails to teach wherein the first heat exchanger is embedded with the solid-solid phase change material. Widstrom teaches an oil conduit 11 embedded with a solid-solid phase change material 15 (Fig. 3B, Para. 0030, 0104, 0107, 0111). Thiagarajan also teaches a heat exchanger 200 having embedded therein a solid-solid phase change material 150 (Fig. 3-4, Para. 0019-21, 0029-31). Therefore it would have been obvious to one of ordinary skill in the art at the time the invention was filed to have modified the system of Appukuttan in view of Widstrom & Thiagarajan such that the first heat exchanger is embedded with the solid-solid phase change material, as taught by Widstrom and Thiagarajan, in order to provide thermal communication between the flow of oil and the phase change material (Widstrom Para. 0104, 0107, 0111; Thiagarajan Para. 0019-21, 0029-31). Appukuttan discusses the phase change material “ located in heat exchange relationship with oil passing through the further heat exchanger 130 in use ” (Para. 0026), and consequently it would have been obvious to embed the phase change material in the heat exchanger to facilitate the heat exchange relationship. Regarding claim 5 , Appukuttan in view of Widstrom & Thiagarajan teaches the thermal management system of claim 1, and Appukuttan further teaches wherein the first heat exchanger 130 is downstream of the oil source 118 (Fig. 3, relative to the flow direction shown by the arrows) and upstream of the second heat exchanger 108 (Fig. 3, interpreting the fuel-oil heat exchanger FOHE 108 as the second heat exchanger). Regarding claim 6 , Appukuttan in view of Widstrom & Thiagarajan teaches the thermal management system of claim 1, and Appukuttan further teaches wherein the first heat exchanger 130 is downstream of the second heat exchanger 122 (interpreted as the air-oil heat exchanger AOHE 122) and upstream of the one or more thermal loads 18 (Fig. 3, relative to the flow direction shown by the arrows). Regarding claim 7 , Appukuttan in view of Widstrom & Thiagarajan teaches the thermal management system of claim 1, and Appukuttan further teaches wherein the second heat exchanger 108, 122 comprises an air-cooled oil cooler 122 (Fig. 3, Para. 0025, AOHE) or a fuel-cooled oil cooler 108 (Fig. 3, Para. 0024, FOHE). Regarding claim 8 , Appukuttan in view of Widstrom & Thiagarajan teaches the thermal management system of claim 1, and Appukuttan further teaches further comprising: a third heat exchanger 108, the third heat exchanger comprising an air-cooled oil cooler or a fuel-cooled oil cooler (Fig. 3, Para. 0024, the third heat exchanger 108 is a “ oil to fuel heat exchanger (FOHE) 108 ”); wherein the first heat exchanger 130 is downstream of the second heat exchanger 122 (Fig. 3, downstream of the “ oil to air heat exchanger (AOHE) 122 ”) and upstream of the third heat exchanger 108 (Fig. 3, the first heat exchanger 130 is between the second and third heat exchangers). Regarding claim 9 , Appukuttan in view of Widstrom & Thiagarajan teaches the thermal management system of claim 1, wherein: the first heat exchanger 130 is configured to be in fluid communication with a bypass airflow of the gas turbine engine (Para. 0031, “ The PCM within the further heat exchanger 130 continues to be cooled by bypass air , thereby rejecting heat to the bypass stream ”). Regarding independent claim 12 , Appukuttan discloses a gas turbine engine 10 (Fig. 1), comprising: a fan 12; a turbomachine operably coupled to the fan for driving the fan (via shaft 26, Fig. 1, Para. 0003), the turbomachine comprising a compressor section 14, 16, a combustion section 18, and a turbine section 20, 22, 24 in serial flow order and together defining a core air flow path (Fig. 1); and a thermal management system (Fig. 3) comprising: an oil source 118 (“oil tank”, Fig. 3, Para. 0025); a pump 120 configured to generate a flow of oil from the oil source (Para. 0025); a first heat exchanger 130 downstream of the oil source (Fig. 3, Para. 0026 “ a further heat exchanger 130 ”); a second heat exchanger 108/122 downstream of the oil source (Fig. 3, either of the “ oil to fuel heat exchanger (FOHE) 108 ” or “ oil to air heat exchanger (AOHE) 122 ”, Para. 0024-25); and one or more thermal loads 18 (Para. 0027, “ engine components to be cooled, such as bearings ”) downstream of the first heat exchanger and the second heat exchanger (Fig. 3, Para. 0027, “ Once the oil flow has passed through the further heat exchanger, it is then passed downstream to an oil side of the FOHE 108 where it is cooled further, by transferring heat to the engine fuel. Oil is then recirculated through a return line 132 to engine components to be cooled, such as bearings, where the oil is again heated ”); wherein the first heat exchanger includes a phase change material (PCM, Para. 0026, “ The further heat exchanger 130 comprise a phase change material (PCM) located in heat exchange relationship with oil passing through the further heat exchanger 130 in use ”). Appukuttan fails to disclose wherein the first heat exchanger includes a solid-solid phase change material. Widstrom teaches an aircraft engine oil system (Fig. 1) for cooling a thermal load (bearings 6A-6D, Para. 0096), the system comprising a heat exchanger 7, wherein the system comprises oil conduits 11 having a phase change material 15 (Fig. 3B, Para. 0107), wherein the phase change material can include a solid-solid phase change material (Para. 0030, “ the material selected for the phase changing material may be any suitable material… Examples include but are not limited to organic and inorganic salts, inorganic eutectics, hydroscopic materials, hydrated salts, organic solutions and solid-solid materials ”). Thiagarajan teaches a heat exchanger 200 (Fig. 3-4) for an aircraft system that includes a phase change material 150 (Para. 0019-22), that can be a solid-solid phase change material (Para. 0029-31) which is described as being able to absorb heat without increasing the temperature of the system, undergoing reversible solid-state crystal structure transitions at certain temperatures; wherein the type of phase change material is selected based on the desired transition temperatures and amount of heat that is desired to be absorbed, with solid-solid phase change materials having a transition temperature over a “ limited temperature range ” (Thiagarajan Para. 0029-31). It has been held to be within the general skill of a worker in the art to select a known material on the basis of its suitability for the intended use as a matter of obvious design choice. In re Leshin , 277 F.2d 197, 125 USPQ 416 (CCPA 1960). See MPEP 2144.07. Therefore it would have been obvious to one of ordinary skill in the art at the time the invention was filed to have modified the system of Appukuttan such that the first heat exchanger’s phase change material is a solid-solid phase change material, such as a material taught in Widstrom and Thiagarajan, in order to provide a phase change material having desired properties such as a desired transition temperature range, and heat absorption capacity (Widstrom Para. 0030; Thiagarajan Para. 0029-31). Appukuttan already discloses the first heat exchanger 130 utilizing a phase change material, and one skilled in the art would know to select from known materials in the art (including solid-solid phase change materials), on the basis of their suitability for the intended use of the system, to achieve a desired level of performance. Regarding claim 14 , Appukuttan in view of Widstrom & Thiagarajan teaches the gas turbine engine of claim 12, but fails to teach wherein the first heat exchanger is embedded with the solid-solid phase change material. Widstrom teaches an oil conduit 11 embedded with a solid-solid phase change material 15 (Fig. 3B, Para. 0030, 0104, 0107, 0111). Thiagarajan also teaches a heat exchanger 200 having embedded therein a solid-solid phase change material 150 (Fig. 3-4, Para. 0019-21, 0029-31). Therefore it would have been obvious to one of ordinary skill in the art at the time the invention was filed to have modified the system of Appukuttan in view of Widstrom & Thiagarajan such that the first heat exchanger is embedded with the solid-solid phase change material, as taught by Widstrom and Thiagarajan, in order to provide thermal communication between the flow of oil and the phase change material (Widstrom Para. 0104, 0107, 0111; Thiagarajan Para. 0019-21, 0029-31). Appukuttan discusses the phase change material “ located in heat exchange relationship with oil passing through the further heat exchanger 130 in use ” (Para. 0026), and consequently it would have been obvious to embed the phase change material in the heat exchanger to facilitate the heat exchange relationship. Regarding claim 16 , Appukuttan in view of Widstrom & Thiagarajan teaches the gas turbine engine of claim 12, wherein: the first heat exchanger 130 is configured to be in fluid communication with a bypass airflow of the gas turbine engine (Para. 0031, “ The PCM within the further heat exchanger 130 continues to be cooled by bypass air , thereby rejecting heat to the bypass strea m ”) . 07-21-aia AIA Claim s 10, 11, 17, 18 is/are rejected under 35 U.S.C. 103 as being unpatentable over Appukuttan in view of Widstrom & Thiagarajan, further in view of Diaz (US 2016/0131035 A1) . Regarding claims 10 & 17 , Appukuttan in view of Widstrom & Thiagarajan teaches the thermal management system and gas turbine of claims 9 & 16 respectively, but fails to teach further comprising a valve configured to selectively allow the bypass airflow to flow through the first heat exchanger. Diaz teaches a heat exchanger 54 (Fig. 3-7, Para. 0034) for cooling oil (Para. 0034), the heat exchanger in fluid communication with a bypass air flow 52 (Para. 0033, Fig. 2), further comprising a valve 86 (a plate having variable geometry permitting retraction and extension) configured to selectively allow bypass airflow 52 to flow through the heat exchanger (Fig. 4-7, Para. 0043-48). Therefore it would have been obvious to one of ordinary skill in the art at the time the invention was filed to have modified the system of Appukuttan in view of Widstrom & Thiagarajan to include a valve configured to selectively allow the bypass airflow to flow through the first heat exchanger, as taught by Diaz, in order to control the amount of bypass air flow through the first heat exchanger in response to a temperature of the heat exchanger and the fluid flowing through the heat exchanger, to optimize the cooling of the oil and first heat exchanger based on engine operating conditions (Diaz Para. 0043-48). Regarding claims 11 & 18 , Appukuttan in view of Widstrom & Thiagarajan teaches the thermal management system and gas turbine of claims 9 & 16 respectively, but fails to teach, wherein: the first heat exchanger comprises a surface heat exchanger; and the surface heat exchanger including a plurality of fins extending into the bypass airflow of the gas turbine engine. Diaz teaches a heat exchanger 54 (Fig. 3-7, Para. 0035-36) for cooling oil (Para. 0034), the heat exchanger comprising a surface heat exchanger 56 (Para. 0034, “ heat exchanger apparatus 54 may be configured to include a surface cooler 56 ”), and surface heat exchanger including a plurality of fins 84 (“ plurality of cooling fins ”, Fig. 4-7, Para. 0040-45) extending into the bypass airflow 52 of the gas turbine engine (Fig. 4-7, the fins extend into and are exposed to the bypass airflow 52; Fig. 8-11, in an alternative embodiment, the heat exchanger 54 and its fins 84 can selectively extend into the bypass airflow 52). Therefore it would have been obvious to one of ordinary skill in the art at the time the invention was filed to have modified the system of Appukuttan in view of Widstrom & Thiagarajan such that the first heat exchanger is a surface heat exchanger having a plurality of fins extending into the bypass airflow, as taught by Diaz, in order to provide direct fluid contact between the first heat exchanger and the bypass airflow while utilizing a plurality of fins to increase the heat transfer surface area of the heat exchanger to improve cooling effectiveness (Diaz Para. 0030, 0040, 0042-45, 0064-65). Surface coolers having a plurality of fins extending into a bypass airflow passage of a gas turbine engine is well-known and common in the art (see Pertinent Prior Art ) . Allowable Subject Matter 12-151-08 AIA 07-43 12-51-08 Claim s 2, 4, 13, 15 are objected to as being dependent upon a rejected base claim, but would be allowable if rewritten in independent form including all of the limitations of the base claim and any intervening claims. 13-03-01 AIA The following is a statement of reasons for the indication of allowable subject matter: Regarding claims 2 & 13 , the closest prior art of record fails to teach or suggest in combination with other claimed limitations, at least a portion of an exterior of the first heat exchanger is formed from the solid-solid phase change material. Regarding claims 4 & 15 , the closest prior art of record fails to teach or suggest in combination with other claimed limitations, the first heat exchanger comprises a plurality of rods extending between a first end and a second end opposite the first end of the first heat exchanger; and the plurality of rods are formed from the solid-solid phase change material. Pertinent Prior Art The prior art made of record on the attached PTO-892 and not relied upon is considered pertinent to applicant's disclosure. Stearns (US 20160024968 A1), Schwarz (US 20150361811 A1) teach oil cooling systems having multiple heat exchangers. Jiang (US 2020/0200040 A1) teaches a surface cooler assembly having a plurality of fins. De Bock (US 20170318710 A1, US 9913411 B2) & Thiagarajan (US 20170010050 A1, US 9476651 B2, US 9909816 B2) teach cooling systems for aircraft avionics that includes a solid-solid phase change material. Contact Information Any inquiry concerning this communication or earlier communications from the examiner should be directed to ALAIN CHAU whose telephone number is (571)272-9444. The examiner can normally be reached on M-F 9am-6pm PST. 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 on 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 an application may be obtained from the Patent Application Information Retrieval (PAIR) system. Status information for published applications may be obtained from either Private PAIR or Public PAIR. Status information for unpublished applications is available through Private PAIR only. For more information about the PAIR system, see http://pair-direct.uspto.gov. Should you have questions on access to the Private PAIR system, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative or access to the automated information system, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000. /ALAIN CHAU/Primary Examiner, Art Unit 3741 Application/Control Number: 19/178,262 Page 2 Art Unit: 3741 Application/Control Number: 19/178,262 Page 3 Art Unit: 3741 Application/Control Number: 19/178,262 Page 4 Art Unit: 3741 Application/Control Number: 19/178,262 Page 5 Art Unit: 3741 Application/Control Number: 19/178,262 Page 6 Art Unit: 3741 Application/Control Number: 19/178,262 Page 7 Art Unit: 3741 Application/Control Number: 19/178,262 Page 8 Art Unit: 3741 Application/Control Number: 19/178,262 Page 9 Art Unit: 3741 Application/Control Number: 19/178,262 Page 10 Art Unit: 3741 Application/Control Number: 19/178,262 Page 11 Art Unit: 3741 Application/Control Number: 19/178,262 Page 12 Art Unit: 3741 Application/Control Number: 19/178,262 Page 13 Art Unit: 3741 Application/Control Number: 19/178,262 Page 14 Art Unit: 3741
Prosecution Insights