DETAILED ACTION
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Preliminary Amendments
Receipt and entry of Applicant’s Preliminary Amendment filed on 11/21/2024 is acknowledged.
Claims 1-28 have been canceled. Claims 29-48 are newly added. Overall, claims 29-48 are pending in this application.
Claim Objections
Claim 47 is objected to because of the following informalities:.
In claim 47, the last line, “a gas turbine engine” should be corrected to:
-- [[a]] the gas turbine engine--,
since “a gas turbine engine” was previously introduced in lines 2-3.
Appropriate correction is required.
Claim Rejections - 35 USC § 112
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claims 33, 34, 39-41 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor, or for pre-AIA the applicant regards as the invention.
Claim 33 recites “a sub-set or module is selectively removable from the heating arrangement”. However, this renders the claim indefinite, as the limitation is referring to a limitation of claim 32 that may not be required. Claim 32, upon which claim 33 depends, recites three structural features that are separated by “and/or”, suggesting all three options are not required, and that only one of the three features is required by broadest reasonable interpretation of the claim (with the other two features being optional). Since the limitation of claim 33 is referring to only one of the three options of claim 32, it is unclear if the claim is now explicitly requiring that particular option (i.e. the conduits divided into discrete groups, each group being a sub-set or module of a heating arrangement body), or if the claim is merely further limiting that particular option (and not requiring it to satisfy the claim). Since the “conduits divided into discrete groups…” that are sub-sets/modules is not required by claim 32, then claim 33 would only apply to that limitation and not the other two options (i.e. if a prior art reads on any of the other two options, satisfying claim 32, then the limitation of claim 33 would not further limit the invention since the features recited in claim 33 are towards a not required feature). If claim 33 is intended to explicitly require the limitation “conduits divided into discrete groups…” of claim 32, revision of the claim language is suggested, such as explicitly stating in claim 33 “wherein the conduits are divided into discrete groups, each group forming the sub-set or module of the heating arrangement body…”, to explicitly, positively recite the limitation.
Claim 39 recites “wherein the sides of each generally truncated cone shape comprise a concave curved profile when viewed in cross-section”. This renders the claim indefinite, as the limitation is referring to a limitation in claim 38 that may not be required. Claim 38 recites three structural features for the supports/baffles separated by “and/or”, suggesting that all three features are not required, and that only one of the three features is required by the broadest interpretation of the claim. Since the limitation of claim 39 is referring to only one of the three options (i.e. the “generally truncated cone shape”), it is unclear if the claim is now explicitly requiring the option of a “generally truncated cone shape” of claim 38, or is only limiting that particular option. Since the “generally truncated cone shape” is not required by claim 38, then the limitations of claim 39 would not be further limiting the claim upon which it depends, since it only applies to that option and not to the other two possible structural features (i.e. if a prior art reads on any of the other two options, satisfying claim 38, then claim 39’s limitations would not apply since the features recited in claim 39 are towards a not required feature). If claim 39 is intended to require the “generally truncated cone shape”, revision of the claim language is suggested, such as explicitly stating in claim 39 that “the supports/baffles each have the generally truncated cone shape…” as recited in claim 38, to explicitly, positively recite the limitation.
Claim 40 recites “the plurality of conduits”. There is insufficient antecedent basis for this limitation in the claims. The claims have only previously introduced “one or more conduits passing [through the internal cone cavity]”, and not explicitly a “plurality of conduits”.
Claim 34, 41 are rejected by virtue of dependence on claims 33 & 40, respectively.
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 § 102
The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action:
A person shall be entitled to a patent unless –
(a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale or otherwise available to the public before the effective filing date of the claimed invention.
(a)(2) the claimed invention was described in a patent issued under section 151, or in an application for patent published or deemed published under section 122(b), in which the patent or application, as the case may be, names another inventor and was effectively filed before the effective filing date of the claimed invention.
Claims 29, 30, 31, 35-40, 42-43 are rejected under 35 U.S.C. 102(a)(2) as being anticipated by Rambo (US 2023/0076757 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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Regarding claim 30, Rambo discloses the fluid heating arrangement of claim 29, 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 discloses the fluid heating arrangement of claim 29, 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 discloses the fluid heating arrangement of claim 29, 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 discloses the fluid heating arrangement of claim 29, 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 discloses the fluid heating arrangement of claim 29, 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 & 39, Rambo discloses the fluid heating arrangement of claim 37, 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. Claim 39 is interpreted as only being required if the “generally truncated cone shape” is present (see rejection under 112(b) above).
Regarding claim 40, Rambo discloses the fluid heating arrangement of claim 29, 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 plurality of 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 discloses the fluid heating arrangement of claim 29, 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 discloses the fluid heating arrangement of claim 29, 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).
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 32-34 are rejected under 35 U.S.C. 103 as being unpatentable over Rambo in view of Hemsworth (US 3,267,673 A).
Regarding claims 32-34, Rambo discloses the fluid heating arrangement of claim 29, 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 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 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.
Note, that claim 32 requires only one of the three described options to satisfy the claim (due to the use of “and/or” between the three described features). Consequently, the features of “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”, as well as recited limitations for these features (in claims 33-34), are 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…”; see rejection under 112(b) above).
Claims 41 are rejected under 35 U.S.C. 103 as being unpatentable over Rambo in view of Brady (US 2023/0358180 A1).
Regarding claim 41, Rambo discloses the fluid heating arrangement of claim 40, 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 fails to disclose 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, 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.
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 the heat exchanger, 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 the heat exchanger 94 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 apparatus 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).
Regarding claim 45, Brady in view of Rambo 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, 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 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, 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).
Regarding claim 48, Brady in view of Rambo teaches the method of claim 47, 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).
Pertinent Prior Art
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure.
Smith (US 2023/0040971 A1, US 11994068 B2) teaches a fluid heating arrangement for heating hydrogen fuel, including an exhaust heat exchanger.
Youssef (US 10,260,371 B2) teaches an exhaust cone having a heat exchange conduit within a recess formed on an outer wall of the exhaust cone.
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/ALAIN CHAU/Primary Examiner, Art Unit 3741