FINAL REJECTION
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
The Amendment filed 04/08/2026 has been entered. Claims 29-48 remain pending in the application. Applicant’s amendments to the Drawings, Specification and Claims have overcome each and every objection and 112(b) rejections previously set forth in the Non-Final Office Action mailed 01/15/2026.
Claim Interpretation
The following is a quotation of 35 U.S.C. 112(f):
(f) Element in Claim for a Combination. – An element in a claim for a combination may be expressed as a means or step for performing a specified function without the recital of structure, material, or acts in support thereof, and such claim shall be construed to cover the corresponding structure, material, or acts described in the specification and equivalents thereof.
The following is a quotation of pre-AIA 35 U.S.C. 112, sixth paragraph:
An element in a claim for a combination may be expressed as a means or step for performing a specified function without the recital of structure, material, or acts in support thereof, and such claim shall be construed to cover the corresponding structure, material, or acts described in the specification and equivalents thereof.
The claims in this application are given their broadest reasonable interpretation using the plain meaning of the claim language in light of the specification as it would be understood by one of ordinary skill in the art. The broadest reasonable interpretation of a claim element (also commonly referred to as a claim limitation) is limited by the description in the specification when 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, is invoked.
As explained in MPEP § 2181, subsection I, claim limitations that meet the following three-prong test will be interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph:
(A) the claim limitation uses the term “means” or “step” or a term used as a substitute for “means” that is a generic placeholder (also called a nonce term or a non-structural term having no specific structural meaning) for performing the claimed function;
(B) the term “means” or “step” or the generic placeholder is modified by functional language, typically, but not always linked by the transition word “for” (e.g., “means for”) or another linking word or phrase, such as “configured to” or “so that”; and
(C) the term “means” or “step” or the generic placeholder is not modified by sufficient structure, material, or acts for performing the claimed function.
Use of the word “means” (or “step”) in a claim with functional language creates a rebuttable presumption that the claim limitation is to be treated in accordance with 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph. The presumption that the claim limitation is interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, is rebutted when the claim limitation recites sufficient structure, material, or acts to entirely perform the recited function.
Absence of the word “means” (or “step”) in a claim creates a rebuttable presumption that the claim limitation is not to be treated in accordance with 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph. The presumption that the claim limitation is not interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, is rebutted when the claim limitation recites function without reciting sufficient structure, material or acts to entirely perform the recited function.
Claim limitations in this application that use the word “means” (or “step”) are being interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, except as otherwise indicated in an Office action. Conversely, claim limitations in this application that do not use the word “means” (or “step”) are not being interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, except as otherwise indicated in an Office action.
This application includes one or more claim limitations that do not use the word “means,” but are nonetheless being interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, because the claim limitation(s) uses a generic placeholder that is coupled with functional language without reciting sufficient structure to perform the recited function and the generic placeholder is not preceded by a structural modifier. Such claim limitation(s) is/are:
“exhaust gas control arrangements arranged to control the ingress and/or egress of exhaust gas into or out of the cone” in claim 43.
The limitation satisfies the three-prong analysis for interpretation under 35 U.S.C 112(f) as follows:
the claim limitation uses a substitute term for “means” that is a generic placeholder: “arrangements”;
the generic placeholder is modified by functional language “arranged to control the ingress and/or egress of exhaust gas into or out of the cone”;
the generic placeholder is not modified by sufficient structure, materials, or acts for performing the claimed function.
Because this/these claim limitation(s) is/are being interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, it/they is/are being interpreted to cover the corresponding structure described in the specification as performing the claimed function, and equivalents thereof.
If applicant does not intend to have this/these limitation(s) interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, applicant may: (1) amend the claim limitation(s) to avoid it/them being interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph (e.g., by reciting sufficient structure to perform the claimed function); or (2) present a sufficient showing that the claim limitation(s) recite(s) sufficient structure to perform the claimed function so as to avoid it/them being interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph.
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.
Claims 29-31, 35-38, 40, 42-43, 47 are rejected under 35 U.S.C. 103 as being unpatentable over Rambo (US 2023/0076757 A1, previously cited) in view of Schimmels (US 2023/0043809 A1).
Regarding independent claim 29, Rambo discloses an aircraft fluid heating arrangement 200 (“waste heat recovery system”, Fig. 2-5), comprising:
an exhaust cone 230 (“tail cone section”) for a gas turbine engine 10, the exhaust cone having an outer body 230A defining an internal cone cavity 222/230B (a cavity forming the “waste heat recovery flowpath 222”, Fig. 4 below, Fig. 5, Para. 0061-62), and the internal cone cavity comprising one or more conduits 98 passing therethrough for communicating fluid through the cavity (the conduits 98 pass through the cavity in the form of a heat exchanger 94, 232 within the cavity, connected as part of a thermal transfer bus, Fig. 4 & 5, Para. 0049, 0068-69);
wherein the outer body of the exhaust cone comprises at least one inlet 222a and at least one outlet 222b to allow exhaust gas to pass into through and out of the exhaust cone (Fig. 4 below & Fig. 5).
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Rambo fails to disclose wherein the conduits are divided into discrete groups, each group forming a sub-set or module of a heating arrangement body.
Schimmels teaches an aircraft fluid heating arrangement body 300 (a heat exchanger that can be placed in an exhaust section 32 of a gas turbine engine, Para. 0070) including a plurality of conduits 304 (plurality of channels or tubes 304 extending through flowpath 302, Fig. 4, Para. 0091), wherein the conduits are divided into discrete groups, each group forming a sub-set or module of a heating arrangement body (Para. 0092-93, “the heat exchanger 300 may be a plurality of discrete heat exchangers 300 arranged in the circumferential direction C. The plurality of discrete heat exchangers 300 may collectively extend substantially continuously in the circumferential direction C, with only relatively small gaps or spacing between the adjacent heat exchangers 300. With such a configuration, the plurality of discrete heat exchanger 300 may collectively extend along the circumferential direction C within the flowpath for at least about 180 degrees… or continuously along the circumferential direction C within the flowpath (e.g., for 360 degrees of the annular passage)”; by being formed as a plurality of discrete heat exchangers, the conduits 304 would be divided into groups associated with each heat exchanger, thus forming sub-sets or modules of the overall heating arrangement body).
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 heating arrangement of Rambo such that the conduits are divided into discrete groups to form sub-sets/modules of a heating arrangement body, as taught by Schimmels, in order to provide an annular heat exchanger formed collectively from a plurality of discrete heat exchanger arranged in the circumferential direction, which would allow for easier repair and maintenance of the heating arrangement (e.g. damage to a single part of the heating arrangement would not necessitate replacement of the entire arrangement, but only single discrete modules). Forming an annular heat exchanger arrangement as a plurality of discrete sub-sets or modules forming an overall body is well-known and common in the art (see for example: Eleftheriou US 9766019 B2 Fig. 4; Pons US 2025/0067211 A1 Fig. 2-3; Nakamura US 3818984 Fig. 1; Kormann DE 102013225989 A1 Fig. 1).
Regarding claim 30, Rambo in view of Schimmels teaches the fluid heating arrangement of claim 29, and Rambo further teaches further comprising a fluid inlet and fluid outlet allowing for fluid to be communicated to and from the conduit(s) within the cavity (Fig. 4 above, see the conduits 98 coming from and flowing back to the heat sink exchanger 96, which form a fluid inlet and fluid outlet for the conduits/heat exchanger 94 in the cavity 230B; Para. 0047-49).
Regarding claim 31, Rambo in view of Schimmels teaches the fluid heating arrangement of claim 29, and Rambo further teaches wherein the one or more conduits 98 are arranged so as to cause fluid to flow in a generally alternating direction between the fore and rear of the cone in an exhaust gas flow direction (Fig. 4 above & 5 below, the conduits 98 direct the fluid flow from the heat sink exchanger 96 towards the heat source exchanger 94 in the exhaust cone cavity in a downstream direction, then back towards the heat sink exchanger 96 in an upstream direction, relative to the exhaust gas flow direction as shown, hence in alternating directions; in Fig. 5 below in particular, the conduits 98 direct the flow between the fore and aft of the exhaust cone as shown in alternating directions through the conduit supports/baffles 242 and the heat source exchanger 94).
Regarding claim 35, Rambo in view of Schimmels teaches the fluid heating arrangement of claim 29, and Rambo further teaches wherein the at least one inlet 222a is in the form of one or more annular circumferentially extending inlet(s) arranged to communicate exhaust gas from an exhaust of an associated engine into the cavity (Fig. 2-5, the inlet of the waste heat recovery flow path 222 is annular about the engine centerline as shown, for receiving a portion of exhaust gas 272 from the primary exhaust flow 220).
Regarding claim 36, Rambo in view of Schimmels teaches the fluid heating arrangement of claim 29, and Rambo further teaches wherein the outlet 222b from the cavity 230B is axially located with respect to the axis of rotation of the exhaust cone (Fig. 4 above, the outlet is coincident with the engine/exhaust cone centerline and axis of rotation as shown).
Regarding claim 37, Rambo in view of Schimmels teaches the fluid heating arrangement of claim 29, and Rambo further teaches wherein the cavity 230B comprises a plurality of conduit supports/baffles 240, 242 extending across a portion of the cross-sectional area of the exhaust cone (Fig. 5 below) and comprising a plurality of apertures arranged to receive and support an associated conduit (the conduits 98 enter the supports/baffles 242 as shown to supply fluid to the heat exchanger 94; Para. 0074-75).
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Regarding claim 38, Rambo in view of Schimmels teaches the fluid heating arrangement of claim 37, and Rambo further teaches wherein:
the supports/baffles are spaced along the length of the cavity from exhaust inlet to exhaust outlet, and/or
the supports/baffles 240, 242 have increasing outer radii towards the exhaust outlet (Fig. 5 above, each of the supports/baffles increase in radii relative to the engine centerline as they extend towards the outlet 222b as shown); and/or
the supports/baffles each have a generally truncated cone shape and comprise a central open end for communicating exhaust gas towards the exhaust of the tail cone; wherein the sides of each generally truncated cone shape comprise a concave curved profile when viewed in cross-section.
Note, the use of the term “and/or” implies that only one of the three options recited is required. Hence, Rambo teaching the option of the supports/baffles having increasing outer radii towards the exhaust outlet reads on the claim.
Regarding claim 40, Rambo in view of Schimmels teaches the fluid heating arrangement of claim 29, and Rambo further teaches further comprising a primary heat exchanger 96 arranged to exchange heat between a fuel 82 for use in an engine (Para. 0057, Fig. 3, for use in the gas turbine engine 103) and a fluid arranged to flow through the one or more conduits 94 within the exhaust cone (Fig. 3, Para. 0049, 0057, a “thermal transfer fluid” that flows through the thermal transfer bus 98 that is in fluid communication with the conduits in the heat exchanger 94 disposed in the exhaust cone cavity as shown).
Regarding claim 42, Rambo in view of Schimmels teaches the fluid heating arrangement of claim 29, and Rambo further teaches wherein the volume of exhaust gas 272 flowing through the exhaust cone and over the conduits 94 is predetermined and the inlet(s) 222a and/or outlet(s) 222b is/are configured to allow a predetermined percentage or volume of exhaust gas to pass through the cone [functional language] (Fig. 4-5, Para. 0074, the inlets 222a and outlets 222b receive a set portion of the exhaust flow from the gas turbine engine downstream of the turbine section 210).
It has been held that, “Where the claimed and prior art products are identical or substantially identical in structure or composition, or are produced by identical or substantially identical processes, a prima facie case of either anticipation or obviousness has been established”. In re Best, 562 F.2d 1252, 1255, 195 USPQ 430, 433 (CCPA 1977); MPEP 2112.01. As Rambo teaches substantially identical structure as the claimed invention, Claim 42 is rejected as anticipated. Since the inlet and outlets 222a, 222b are not described as possessing variable area geometry, the amount of exhaust flow passing through the cavity would naturally be “predetermined”. While Rambo contemplates a rotatable guide vane 240, they also do not require the guide vane to be adjustable, as it can serve to only “stabilize the tail cone section 230” (Para. 0074).
Regarding claim 43, Rambo in view of Schimmels teaches the fluid heating arrangement of claim 29, and Rambo further teaches wherein the volume of exhaust gas 272 flowing through the exhaust cone and over the conduits 94 may be selectively controlled by means of one or more exhaust gas control arrangements 242 arranged to control the ingress and/or egress of exhaust gas into or out of the cone (Fig. 4, 5, Para. 0074, “the waste heat recovery system 200 includes a valve 242 that is disposed within a second portion of the waste heat recovery flowpath 222 spaced from a first portion of the waste heat recovery flowpath 222 containing the heat source exchanger 94”; the valve 242 can control a percentage of mass flow rate through the exhaust cone cavity; the valve can be a rotatable guide vane (such as a rotatable version of the guide vane 240), a radially actuating door, or a translating sled).
Regarding independent claim 47, Rambo discloses a method of heating a fuel or fluid for a gas turbine engine (a thermal transfer fluid, and a fuel, Para. 0049, 0055-57), the engine comprising a fuel or fluid heating arrangement (Fig. 2-5) comprising an exhaust cone 230 for a gas turbine engine (Fig. 4 & 5 above), the exhaust cone having an outer body 230A defining an internal cone cavity 230B/222 (forming a “waste heat recovery flowpath”), the internal cone cavity comprising one or more conduits 94 (conduits forming a heat source exchanger 94, Para. 0045-46, 0057) passing therethrough for communicating fuel or fluid through the cavity (communicating thermal transfer fluid from the thermal transfer bus 98, Fig. 4 & 5 above, Para. 0063, 0069-70), and wherein the outer body of the exhaust cone comprises at least one inlet 222a and at least one outlet 222b (Fig. 4 & 5 above) to allow exhaust gas to pass into through and out of the exhaust cone, the method comprising:
(a) causing fuel or fluid to be communicated into the conduit(s) from a fuel or fluid source 96 (pump 100 drives the fluid from a heat sink exchanger 96 that directs the fluid through the thermal transfer bus 98 to the conduits 94, Fig. 2, 3 & 4, Para. 0056-57);
(b) causing exhaust gas from the engine to pass through the exhaust cone and around the conduits to cause heat transfer to the fuel or fluid contained therein (Fig. 4 & 5 above, Para. 0063, 0073); and
(c) communicating heated fuel or fluid to a gas turbine engine 10, 103 (Fig. 3-5, from the conduits/heat exchanger 94, the fluid is circulated through the thermal transfer bus back to the gas turbine engine and the heat sink exchanger 96, to transfer heat from the thermal transfer fluid to either fuel or compressor air flow, Fig. 2 & 3).
Rambo fails to disclose wherein the conduits are divided into discrete groups, each group forming a sub-set or module of a heating arrangement body.
Schimmels teaches a method of heating a fuel/fluid in a gas turbine engine including using a fluid heating arrangement body 300 (a heat exchanger that can be placed in an exhaust section 32 of a gas turbine engine, Para. 0070) including a plurality of conduits 304 (plurality of channels or tubes 304 extending through flowpath 302, Fig. 4, Para. 0091), wherein the conduits are divided into discrete groups, each group forming a sub-set or module of a heating arrangement body (Para. 0092-93, “the heat exchanger 300 may be a plurality of discrete heat exchangers 300 arranged in the circumferential direction C. The plurality of discrete heat exchangers 300 may collectively extend substantially continuously in the circumferential direction C, with only relatively small gaps or spacing between the adjacent heat exchangers 300. With such a configuration, the plurality of discrete heat exchanger 300 may collectively extend along the circumferential direction C within the flowpath for at least about 180 degrees… or continuously along the circumferential direction C within the flowpath (e.g., for 360 degrees of the annular passage)”; by being formed as a plurality of discrete heat exchangers, the conduits 304 would be divided into groups associated with each heat exchanger, thus forming sub-sets or modules of the overall heating arrangement body).
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 method of Rambo such that the conduits are divided into discrete groups to form sub-sets/modules of a heating arrangement body, as taught by Schimmels, in order to provide an annular heat exchanger formed collectively from a plurality of discrete heat exchanger arranged in the circumferential direction, which would allow for easier repair and maintenance of the heating arrangement (e.g. damage to a single part of the heating arrangement would not necessitate replacement of the entire arrangement, but only single discrete modules). Forming an annular heat exchanger arrangement as a plurality of discrete sub-sets or modules forming an overall body is well-known and common in the art (see for example: Eleftheriou US 9766019 B2 Fig. 4; Pons US 2025/0067211 A1 Fig. 2-3; Nakamura US 3818984 Fig. 1; Kormann DE 102013225989 A1 Fig. 1).
Claims 32 are rejected under 35 U.S.C. 103 as being unpatentable over Rambo in view of Schimmels, further in view of Hemsworth (US 3,267,673 A, previously cited).
Regarding claims 32-34, Rambo in view of Schimmels teaches the fluid heating arrangement of claim 29, and Rambo further teaches wherein the one or more conduits 98 are in the form of a heat exchanger 94, 232 extending between the fore and aft of the cavity (Fig. 4 & 5 above, the heat exchanger extends some axial distance between the fore and aft of the cavity) and defining one or more fluid flow paths within the cavity 230B (Fig. 4 & 5 above, the conduits 98 feed into and receive flow from a heat exchanger 94 within the cavity; the heat exchanger can be annular, Para. 0068, Fig. 4).
Rambo in view of Schimmels fails to teach wherein: the one or more conduits are in the form of a generally cylindrical heat exchanger having a plurality of pipes extending between the fore and aft of the cavity and defining one or more fluid flow paths within the cavity; and/or the spacing between adjacent conduits increases towards the central axis of the heat exchanger; and/or the conduits are divided into discrete groups, each group forming a sub-set or module of a heating arrangement body; wherein a sub-set or module is selectively removable from the heating arrangement; wherein modules are fluidly interconnected at one or both ends of a module to an adjacent module.
Hemsworth teaches a generally cylindrical heat exchanger 10 (recuperator) in heat exchange communication with a flow of exhaust from a gas turbine engine (Fig. 1-4), the heat exchanger having a plurality of pipes 31 (U-shaped heat exchange tubes) extending longitudinally across an exhaust section (Fig. 1 & 2) and defining one or more fluid flow paths (there are a plurality of parallel tubes 31 in the heat exchanger each creating a respective fluid flow path connected to headers 35 & 36).
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 arrangement of Rambo in view of Schimmels such that the one or more conduits form a generally cylindrical heat exchanger having a plurality of tubes defining one or more fluid flow paths, as taught by Hemsworth, in order to provide a heat exchanger formed by a bundle of separated tubes that exhibits reduced thermal stress and is accommodating to thermal expansion (Hemsworth Col. 4, ln. 56-73). The plurality of tubes also being U-shaped would allow the fluid therein to pass across the exhaust in the cavity twice, improving heat transfer. Schimmels also teaches their heat exchanger 200, 300 including conduits 304 that can extend axially while being circumferentially arranged (Schimmels Para. 0093).
Note, that claim 32 requires only one of the two described options to satisfy the claim (due to the use of “and/or” between the two described features). Consequently, the features of “the spacing between adjacent conduits increases towards the central axis of the heat exchanger”, is interpreted as not being required by the claim, so long as another one of the features in claim 32 is satisfied (i.e. the “generally cylindrical heat exchanger…”).
Claims 33 are rejected under 35 U.S.C. 103 as being unpatentable over Rambo in view of Schimmels, further in view of Pons (US 2025/0067211 A1).
Regarding claim 33, Rambo in view of Schimmels teaches the fluid heating arrangement of claim 29, but fails to teach wherein the sub-set or module is selectively removable from the heating arrangement.
Pons teaches a heating arrangement 11 having a plurality of conduits 12 that are divided into modules 31 (Fig. 2-3), the modules selectively removable from the heating arrangement (Para. 0095, “The heat exchanger 11 may be sectorized and comprise at least two sectors 31 placed circumferentially end to end or circumferentially distant from each other, each sector 31 of the heat exchanger 11 comprising a sub-inlet 32 of the first circuit 12 connected to the outlet 14 of the compressor 4. The first circuit 12 can be subdivided into a plurality of sub-first circuits, and each sector 31 can comprise a sub-first circuit… The advantage of having a sectorized heat exchanger 11 is that it simplifies maintenance and allows a defective sector 31 to be replaced independently of the others”).
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 Rambo in view of Schimmels such that the sub-set or module of the heating arrangement is selectively removable, as taught in Pons, in order to simplify maintenance by allowing damaged sub-sets/modules to be easily replaced without affecting the rest of the sub-sets/modules (Pons Para. 0095).
Claim 41 is rejected under 35 U.S.C. 103 as being unpatentable over Rambo in view of Schimmels, further in view of Brady (US 2023/0358180 A1, previously cited).
Regarding claim 41, Rambo in view of Schimmels teaches the fluid heating arrangement of claim 40, and Rambo further teaches wherein the primary heat exchanger 96 is arranged to be in fluid communication with a fuel source 82 (Fig. 3, Para. 0057-58) and a fuel delivery system of an engine and the plurality of conduits 98 are arranged to exchange heat from exhaust gas to a fluid (thermal transfer fluid) contained within the conduits (Para. 0049, 0052-54).
Rambo in view of Schimmels fails to teach wherein the fuel source is a cryogenic fuel source.
Brady teaches a fluid heating arrangement (Fig. 4) including a primary heat exchanger 405 (vaporizer) in fluid communication with a cryogenic fuel source 306 (liquid hydrogen) coupled to a fuel delivery system of an engine (Fig. 4, a gas turbine engine), and conduits 404 arranged to exchange heat from exhaust gas to a fluid within the conduits (“heat exchange fluid”, Para. 0059-62).
Therefore it would have been obvious to one of ordinary skill in the art at the time the invention was filed to have incorporated into the system of Rambo in view of Schimmels, the fuel source being a cryogenic fuel source, as taught by Brady, in order to utilize the fluid heating arrangement to vaporize cryogenic/liquid hydrogen fuel for use in the engine (Brady Para. 0059-62), hydrogen being an advantageous fuel having lower carbon emissions, lower fuel consumption, and greater energy production (Brady Para. 0002).
Claims 44-48 are rejected under 35 U.S.C. 103 as being unpatentable over Brady in view of Rambo, further in view of Schimmels.
Regarding independent claim 44, Brady discloses a cryogenic fuel heating arrangement for a gas turbine engine (Fig. 3), comprising:
a heat exchanging apparatus contained within an exhaust section 128 of a gas turbine engine 100 (Fig. 3, Para. 0053, part of conduit 302 in the exhaust section), a heat exchanger (a “waste heat recovery vaporizer”) in fluid communication with a cryogenic fuel tank 306 and an engine fuel system (Fig. 3), wherein the heat exchanging apparatus is to transfer energy from the exhaust gas to the cryogenic fuel (Para. 0053, “the conduit(s) 302 carry the hydrogen at least partially through and/or around the turbine section 126 and/or the exhaust section 128 of the gas turbine 100 (e.g., an aft portion of the gas turbine 100)… the hydrogen can receive thermal energy from the combustion gases 160. As such, a portion of the conduit(s) 302 can form a vaporizer (e.g., a waste heat recovery vaporizer) that enables the thermal energy from the combustion gases 160 to convert the hydrogen to a gaseous or super-critical phase in preparation for combustion”).
Brady fails to disclose the heat exchanging apparatus contained within an exhaust tail cone of a gas turbine engine, the exhaust tail cone having an outer body defining an internal cone cavity, and the internal cone cavity comprising one or more conduits, wherein the outer body of the exhaust cone comprises at least one inlet and at least one outlet to allow engine exhaust gas to pass through the heat exchanging apparatus.
Rambo teaches a heat exchanging apparatus contained within an exhaust tail cone 230 of a gas turbine engine (Fig. 2-5), the exhaust tail cone having an outer body 230A defining an internal cone cavity 230B (Fig. 4 & 5 above), and the internal cone cavity comprising a heat exchanger 94 with one or more conduits 98 in fluid communication with a fluid to be heated (a thermal transfer fluid, Para. 0049, 0068-69), wherein the outer body of the exhaust cone comprises at least one inlet 222a and at least one outlet 222b to allow engine exhaust gas to pass through the heat exchanging apparatus (Fig. 4 & 5 above).
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 cryogenic heating arrangement of Brady such that the heat exchange apparatus in the exhaust section is within an exhaust tail cone of the gas turbine engine, the heat exchanger being within an internal cavity of the exhaust cone wherein at least one inlet and outlet allows engine exhaust gas to pass through the heat exchanging apparatus, as taught by Rambo, in order to improve waste heat recovery from the exhaust gases by directing a parallel flow of exhaust into a passage in the exhaust cone where the heat exchange apparatus is disposed, increasing the allowable pressure drop through the heat exchanger while minimizing adverse effects of the engine performance, as opposed to placing the heat exchanger within the primary exhaust flowpath (Rambo Para. 0028-29).
Brady in view of Rambo still fails to disclose wherein the conduits are divided into discrete groups, each group forming a sub-set or module of a heating arrangement body.
Schimmels teaches an aircraft fluid heating arrangement body 300 (a heat exchanger that can be placed in an exhaust section 32 of a gas turbine engine, Para. 0070) including a plurality of conduits 304 (plurality of channels or tubes 304 extending through flowpath 302, Fig. 4, Para. 0091), wherein the conduits are divided into discrete groups, each group forming a sub-set or module of a heating arrangement body (Para. 0092-93, “the heat exchanger 300 may be a plurality of discrete heat exchangers 300 arranged in the circumferential direction C. The plurality of discrete heat exchangers 300 may collectively extend substantially continuously in the circumferential direction C, with only relatively small gaps or spacing between the adjacent heat exchangers 300. With such a configuration, the plurality of discrete heat exchanger 300 may collectively extend along the circumferential direction C within the flowpath for at least about 180 degrees… or continuously along the circumferential direction C within the flowpath (e.g., for 360 degrees of the annular passage)”; by being formed as a plurality of discrete heat exchangers, the conduits 304 would be divided into groups associated with each heat exchanger, thus forming sub-sets or modules of the overall heating arrangement body).
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 cryogenic fuel heating arrangement of Brady in view of Rambo such that the conduits are divided into discrete groups to form sub-sets/modules of a heating arrangement body, as taught by Schimmels, in order to provide an annular heat exchanger formed collectively from a plurality of discrete heat exchanger arranged in the circumferential direction, which would allow for easier repair and maintenance of the heating arrangement (e.g. damage to a single part of the heating arrangement would not necessitate replacement of the entire arrangement, but only single discrete modules). Forming an annular heat exchanger arrangement as a plurality of discrete sub-sets or modules forming an overall body is well-known and common in the art (see for example: Eleftheriou US 9766019 B2 Fig. 4; Pons US 2025/0067211 A1 Fig. 2-3; Nakamura US 3818984 Fig. 1; Kormann DE 102013225989 A1 Fig. 1).
Regarding claim 45, Brady in view of Rambo & Schimmels teaches the cryogenic fuel heating arrangement for a gas turbine engine of claim 44, but fails to disclose wherein the volume of exhaust gas flow is selectively controlled in response to control signals from a control apparatus.
Rambo teaches the volume of exhaust gas flow is selectively controlled in response to control signals from a control apparatus (Para. 0074-75, Fig. 5, controlled by a valve 242 that “may be a rotatable guide vane, a radially actuating door, or a translating sled that adjusts the parallel stream inlet flow area”; the valve controls the percentage mass flow rate of the portion of exhaust gas flow through the exhaust cone cavity relative to the total exhaust flow, and consequently a “volume” of the exhaust gas flow; a control apparatus providing control signals to this valve is implicit based on the disclosure).
Therefore it would have been obvious to one of ordinary skill in the art at the time the invention was filed to have incorporated into the arrangement of Brady in view of Rambo & Schimmels, selectively controlling the volume of exhaust gas flow in response to control signals from a control apparatus, as suggested in Rambo, in order to control the percentage of exhaust gas mass flow rate that passes through the internal cavity and through the heat exchanging apparatus, thereby controlling the heating of the fuel in the exhaust cone (Rambo Para. 0074-75). While Rambo does not explicitly discuss a control apparatus providing control signals, the control of the valve 242 that is selectively operated to open and close the passageway to the internal cavity of the exhaust cone would make implicit a controller to operate the valve. One skilled in the art would know to include a control apparatus to operate the valves in the manner described.
Regarding claim 46, Brady in view of Rambo & Schimmels teaches the cryogenic fuel heating arrangement for a gas turbine engine of claim 44, and Brady further teaches wherein the cryogenic fuel 306 is liquid hydrogen (Fig. 3, Para. 0045, “a hydrogen storage tank 306 (e.g., a hydrogen supply) that stores the hydrogen in a liquid or cryogenic state”; Para. 0022, 0026).
Regarding independent claim 47, Brady discloses a method of heating a fuel or fluid for a gas turbine engine, the engine comprising a fuel or fluid heating arrangement (Fig. 3) comprising an exhaust section 128 (Fig. 3, Para. 0053, part of conduit 302 in the exhaust section), a one or more conduits passing therethrough (part of the conduit 302 forming a “waste heat recovery vaporizer” in the exhaust section) for communicating fuel or fluid through the exhaust section, the method comprising:
(a) causing fuel or fluid to be communicated into the conduit(s) from a fuel or fluid source 96 (pump 100 drives the fluid from a heat sink exchanger 96 that directs the fluid through the thermal transfer bus 98 to the conduits 94, Fig. 2, 3 & 4, Para. 0056-57);
(b) causing exhaust gas from the engine to pass around the conduits to cause heat transfer to the fuel or fluid contained therein (Para. 0053, “the conduit(s) 302 carry the hydrogen at least partially through and/or around the turbine section 126 and/or the exhaust section 128 of the gas turbine 100 (e.g., an aft portion of the gas turbine 100)… the hydrogen can receive thermal energy from the combustion gases 160. As such, a portion of the conduit(s) 302 can form a vaporizer (e.g., a waste heat recovery vaporizer) that enables the thermal energy from the combustion gases 160 to convert the hydrogen to a gaseous or super-critical phase in preparation for combustion”); and
(c) communicating heated fuel or fluid to a gas turbine engine 100 (Fig. 3, the heated fuel is communicated to the combustor section 124 of the gas turbine engine 100, Para. 0043-45, 0050-53, 0056).
Brady fails to disclose an exhaust cone for a gas turbine engine, the exhaust cone having an outer body defining an internal cone cavity, the internal cone cavity comprising one or more conduits passing therethrough for communicating fuel or fluid through the cavity, wherein the conduits are divided into discrete groups, each group forming a sub-set or module of a heating arrangement body, and wherein the outer body of the exhaust cone comprises at least one inlet and at least one outlet to allow exhaust gas to pass into through and out of the exhaust cone; the method comprising: (b) causing exhaust gas from the engine to pass through the exhaust cone and around the conduits to cause heat transfer to the fuel or fluid contained therein.
Rambo teaches a fuel or fluid heating arrangement (Fig. 2-5) comprising an exhaust cone 230 for a gas turbine engine (Fig. 4 & 5 above), the exhaust cone having an outer body 230A defining an internal cone cavity 230B/222 (forming a “waste heat recovery flowpath”), the internal cone cavity comprising one or more conduits 94, 98 (conduits forming a heat source exchanger 94, Para. 0045-46, 0057) passing therethrough for communicating fuel or fluid through the cavity (communicating thermal transfer fluid from the thermal transfer bus 98, Fig. 4 & 5 above, Para. 0063, 0069-70), and wherein the outer body of the exhaust cone comprises at least one inlet 222a and at least one outlet 222b (Fig. 4 & 5 above) to allow exhaust gas to pass into through and out of the exhaust cone; and a method step comprising (b) causing exhaust gas from the engine to pass through the exhaust cone 230 and around the conduits to cause heat transfer to the fuel or fluid contained therein (Fig. 4 & 5 above, Para. 0063, 0073).
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 method of Brady such that the heat exchange apparatus in the exhaust section is within an exhaust tail cone of the gas turbine engine, the exhaust cone having an outer body and an internal cone cavity comprising one or more conduits for communicating the fuel or fluid, wherein at least one inlet and outlet on the outer body allows engine exhaust gas to pass into and out of the exhaust cone, causing the exhaust gas to transfer heat to the fuel or fluid in the conduits, as taught by Rambo, in order to improve waste heat recovery from the exhaust gases to the fuel/fluid, by directing a parallel flow of exhaust into a passage/internal cavity in the exhaust cone where the fluid heating arrangement is disposed, increasing the allowable pressure drop through the heat exchanger while minimizing adverse effects of the engine performance, as opposed to placing the heat exchanger within the primary exhaust flowpath (Rambo Para. 0028-29).
Brady in view of Rambo still fails to teach wherein the conduits are divided into discrete groups, each group forming a sub-set or module of a heating arrangement body.
Schimmels teaches a method of heating a fuel/fluid in a gas turbine engine including using a fluid heating arrangement body 300 (a heat exchanger that can be placed in an exhaust section 32 of a gas turbine engine, Para. 0070) including a plurality of conduits 304 (plurality of channels or tubes 304 extending through flowpath 302, Fig. 4, Para. 0091), wherein the conduits are divided into discrete groups, each group forming a sub-set or module of a heating arrangement body (Para. 0092-93, “the heat exchanger 300 may be a plurality of discrete heat exchangers 300 arranged in the circumferential direction C. The plurality of discrete heat exchangers 300 may collectively extend substantially continuously in the circumferential direction C, with only relatively small gaps or spacing between the adjacent heat exchangers 300. With such a configuration, the plurality of discrete heat exchanger 300 may collectively extend along the circumferential direction C within the flowpath for at least about 180 degrees… or continuously along the circumferential direction C within the flowpath (e.g., for 360 degrees of the annular passage)”; by being formed as a plurality of discrete heat exchangers, the conduits 304 would be divided into groups associated with each heat exchanger, thus forming sub-sets or modules of the overall heating arrangement body).
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 method of Brady in view of Rambo such that the conduits are divided into discrete groups to form sub-sets/modules of a heating arrangement body, as taught by Schimmels, in order to provide an annular heat exchanger formed collectively from a plurality of discrete heat exchanger arranged in the circumferential direction, which would allow for easier repair and maintenance of the heating arrangement (e.g. damage to a single part of the heating arrangement would not necessitate replacement of the entire arrangement, but only single discrete modules). Forming an annular heat exchanger arrangement as a plurality of discrete sub-sets or modules forming an overall body is well-known and common in the art (see for example: Eleftheriou US 9766019 B2 Fig. 4; Pons US 2025/0067211 A1 Fig. 2-3; Nakamura US 3818984 Fig. 1; Kormann DE 102013225989 A1 Fig. 1).
Regarding claim 48, Brady in view of Rambo & Schimmels teaches the method of claim 47, and Brady further teaches wherein the fuel or fluid is a cryogenic liquid hydrogen fuel (Fig. 3, Para. 0045, “a hydrogen storage tank 306 (e.g., a hydrogen supply) that stores the hydrogen in a liquid or cryogenic state”; Para. 0022, 0026).
Allowable Subject Matter
Claims 34, 39 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.
Response to Arguments
Applicant’s arguments with respect to independent claims 29, 44, 47 have been considered but are moot in view of the new grounds of rejection that was necessitated by Applicant’s amendment. However, to the extent possible, Applicant’s arguments have been addressed in the body of the rejections, at the appropriate locations.
Contact Information
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).
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/ALAIN CHAU/Primary Examiner, Art Unit 3741
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