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 11/07/2025 has been entered. Claims 20 has been cancelled. Claim 21 is newly added. Claims 1-19, 21 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 08/12/2025.
Double Patenting
The nonstatutory double patenting rejection is based on a judicially created doctrine grounded in public policy (a policy reflected in the statute) so as to prevent the unjustified or improper timewise extension of the “right to exclude” granted by a patent and to prevent possible harassment by multiple assignees. A nonstatutory double patenting rejection is appropriate where the conflicting claims are not identical, but at least one examined application claim is not patentably distinct from the reference claim(s) because the examined application claim is either anticipated by, or would have been obvious over, the reference claim(s). See, e.g., In re Berg, 140 F.3d 1428, 46 USPQ2d 1226 (Fed. Cir. 1998); In re Goodman, 11 F.3d 1046, 29 USPQ2d 2010 (Fed. Cir. 1993); In re Longi, 759 F.2d 887, 225 USPQ 645 (Fed. Cir. 1985); In re Van Ornum, 686 F.2d 937, 214 USPQ 761 (CCPA 1982); In re Vogel, 422 F.2d 438, 164 USPQ 619 (CCPA 1970); In re Thorington, 418 F.2d 528, 163 USPQ 644 (CCPA 1969).
A timely filed terminal disclaimer in compliance with 37 CFR 1.321(c) or 1.321(d) may be used to overcome an actual or provisional rejection based on nonstatutory double patenting provided the reference application or patent either is shown to be commonly owned with the examined application, or claims an invention made as a result of activities undertaken within the scope of a joint research agreement. See MPEP § 717.02 for applications subject to examination under the first inventor to file provisions of the AIA as explained in MPEP § 2159. See MPEP § 2146 et seq. for applications not subject to examination under the first inventor to file provisions of the AIA . A terminal disclaimer must be signed in compliance with 37 CFR 1.321(b).
The filing of a terminal disclaimer by itself is not a complete reply to a nonstatutory double patenting (NSDP) rejection. A complete reply requires that the terminal disclaimer be accompanied by a reply requesting reconsideration of the prior Office action. Even where the NSDP rejection is provisional the reply must be complete. See MPEP § 804, subsection I.B.1. For a reply to a non-final Office action, see 37 CFR 1.111(a). For a reply to final Office action, see 37 CFR 1.113(c). A request for reconsideration while not provided for in 37 CFR 1.113(c) may be filed after final for consideration. See MPEP §§ 706.07(e) and 714.13.
The USPTO Internet website contains terminal disclaimer forms which may be used. Please visit www.uspto.gov/patent/patents-forms. The actual filing date of the application in which the form is filed determines what form (e.g., PTO/SB/25, PTO/SB/26, PTO/AIA /25, or PTO/AIA /26) should be used. A web-based eTerminal Disclaimer may be filled out completely online using web-screens. An eTerminal Disclaimer that meets all requirements is auto-processed and approved immediately upon submission. For more information about eTerminal Disclaimers, refer to www.uspto.gov/patents/apply/applying-online/eterminal-disclaimer.
Claims 1-5 are rejected on the ground of nonstatutory double patenting as being unpatentable over claims 1, 6-8 of U.S. Patent No. 12,359,816, in view of Chang (US 2016/0215980 A1, cited in the 06/24/2025 Information Disclosure Statement).
Regarding independent claim 1, the patent claims a combustor assembly, comprising:
a combustion chamber (implied by the “combustor liner” in claim 1; explicitly claimed in claim 9) including a combustion chamber length (implicit); and
a liner, the liner including:
a first portion and a second portion extending in a substantially axial direction, the first portion axially forward of the second portion (claim 1, col. 8, ln. 33-35),
a step connecting the first portion and the second portion (claim 1, col. 8, ln. 36), and
a plurality of slots extending through the step (claim 1, col. 44-46, the “first slot” and “second slot”);
wherein the first portion has a first length, the second portion has a second length, the step has a step length, and the first length and the second length are at least twice the step length (claim 6);
wherein the liner is a ceramic component (claim 1, col. 41-43, “the first portion, second portion, and step are formed of a ceramic matrix composite material”).
The patent fails to explicitly claim the liner is a unitary ceramic component that extends at least 50% of the combustion chamber length.
Chang teaches a combustion chamber liner 100 that is a unitary ceramic component (Para. 0047-48, “the liner 100 is a ceramic-based material, such as a ceramic matrix composite (CMC) material… The liner 100 can be formed as a single piece.”) that extends at least 50% of the combustion chamber length (Fig. 2, the liner 100 extends across the entire combustion chamber length as shown; Para. 0045, the liner 100 defines the combustion chamber 102; Para. 0053).
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 combustor assembly of the patent such that the liner is a unitary ceramic component extending at least 50% of the combustion chamber length, as taught by Chang, in order to simplify the manufacture of the liner, forming the entire combustion liner (or at least one of the radially inner or outer liners) as a single piece without seams or joints, or necessitating other attachment/coupling means (Chang Para. 0047-48, 0053).
Regarding claim 2, the patent claims wherein the step is arranged at an angle to the second portion that is less than 90° such that the step slants axially forward from the second portion to the first portion (claim 8).
Regarding claim 3, the patent claims wherein the step joins the second portion at a fillet on an inner side of the liner facing into the combustion chamber (claim 1, col. 8, ln. 37-39).
Regarding claim 4, the patent claims wherein a ratio of a height of one of the plurality of slots to a height of the step is greater than 0.66 (claim 1, ln. 44-45).
Regarding claim 5, the patent claims wherein one of the plurality of slots includes an outlet including a perimeter with at least one curve (claim 7).
Claims 6-10, 12-15 rejected on the ground of nonstatutory double patenting as being unpatentable over claims 1, 6-8 of U.S. Patent No. 12,359,816 in view of Chang, further in view of Pidcock (US 6,408,628, cited in the 06/24/25 Information Disclosure Statement).
Regarding claim 6 & 7, the patent in view of Chang claims the combustor assembly of claim 1 (see claim 1 above), but fails to claim wherein the liner is arranged within an outer shell such that a gap is formed between the outer shell and the liner; wherein the gap is configured to receive cooling airflow, and wherein the plurality of slots are configured to communicate the cooling airflow from an outer side of the liner to an inner side of the liner facing into the combustion chamber. The patent does claim an outer shell with a gap between the outer shell and liner in a different embodiment of claims 13, 14.
Pidcock teaches a combustor assembly having a liner 29B that is arranged within an outer shell 27 (outer wall) such that a gap 44 is formed between the outer shell and the liner (Pidcock Fig. 6 below); and wherein the gap 44 is configured to receive cooling airflow (via holes 42 in the outer shell 27, Col. 5, ln. 8-11), and wherein the plurality of slots 46 are configured to communicate the cooling airflow from an outer side of the liner to an inner side of the liner facing into the combustion chamber (Col. 5, ln. 12-17, ln. 46-55).
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 claimed assembly, the outer shell with gap between the shell and liner to receive cooling airflow that is communicated from an outer side of the liner to an inner side of the liner, as taught by Pidcock, in order to improve the cooling of the combustion liner by having an impingement cooling liner/shell directing cooling flow towards the combustion liner, and using the plurality of slots to promote film cooling of the hot side of the liner (Pidcock Col. 5, ln. 8-17, ln. 46-55).
Regarding claim 8, the patent in view of Chang & Pidcock claims the combustor assembly of claim 7, but fails to claim wherein the plurality of slots are configured to communicate the cooling airflow in a direction substantially parallel to an inner surface of the second portion.
Pidcock teaches wherein the plurality of slots 46 are configured to communicate the cooling airflow L in a direction substantially parallel to an inner surface of the second portion 32_2 (Fig. 6, the airflow L exiting the slots 46 would be swept in a downstream direction by the upstream cooling flow K exiting the gap in the liners 29A & 29B, and would flow parallel to the inner surface of the second portion).
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 claimed assembly such that the plurality of slots are configured to communicate the cooling airflow in a direction substantially parallel to an inner surface of the second portion, as taught by Pidcock, in order to improve the cooling of the combustor liner by promoting film cooling of the hot side of the liner.
Regarding claim 9, 10, the patent in view of Chang & Pidcock claims the combustor assembly of claim 6, but fails to claim wherein the outer shell includes a step adjacent to the step of the liner; wherein the step of the liner is arranged axially aft of the step of the outer shell;
Pidcock further teaches wherein the outer shell 27 includes a step 22A adjacent to the step of the liner (Fig. 6, the step in the liner where the slots 46 are formed); and wherein the step 32A of the liner is arranged axially aft of the step 22A of the outer shell 27 (Fig. 6, relative to the flow direction of cooling air through the outer shell and through the liner).
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 claimed assembly such that the outer shell includes a step adjacent the step of the liner; of the step of the liner being arranged axially aft of the step of the outer shell, as taught by Pidcock, in order to conform the shape of the outer shell to the shape of the liner and help direct the cooling air flow through the gap between the liner and outer shell.
Regarding claim 12, the patent in view of Chang & Pidcock claims the combustor assembly of claim 6, but fails to claim wherein the outer shell is secured to a dome assembly at a location axially forward of the first portion, and wherein the liner is secured to the outer shell.
Pidcock teaches wherein the outer shell 27 is secured to a dome assembly 26 at a location axially forward of the first portion (Fig. 2), and wherein the liner is secured to the outer shell (via threaded plugs 34 and nuts 36, Fig. 2, Col. 4, ln. 56-60).
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 claimed assembly such that the outer shell is secured to a dome assembly forward of the first portion and the liner being secured to the outer shell, as taught by Pidcock, in order to secure the liner and outer shell to the overall combustor assembly. Having a dome assembly with the outer shell secured thereto is well-known in the art, as is having the combustor liner portions secured to an outer shell.
Regarding claim 13, the patent in view of Chang & Pidcock claims the combustor assembly of claim 6, but fails to claim wherein the liner is a first liner and further comprising a second liner extending axially aft of the first liner.
Pidcock teaches wherein the liner 29B is a first liner (Fig. 6) and further comprising a second liner 29A extending axially aft of the first liner (Fig. 6 below, there is another liner 29A downstream of the first liner as shown).
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 claimed assembly to include a second liner extending axially aft of the first liner, as taught by Pidcock, in order to provide additional combustion liner wall elements for protecting additional sections of the combustor downstream of the first portion (Pidcock Col. 4, ln. 45-55, Col. 5, ln. 46-55).
Regarding claim 14, the patent in view of Chang & Pidcock claims the combustor assembly of claim 13, but fails to claim wherein the second liner axially overlaps the second portion of the first liner, and wherein a space is formed between the second portion and the second liner.
Pidcock teaches wherein the second liner 29A axially overlaps the second portion 32_2 of the first liner (Fig. 6 below, the ends 30, 31 of the second and first liners overlap axially as shown), and wherein a space is formed between the second portion and the second liner (a radial gap between the edges 30, 31 of the second liner and first liner as shown, for issuing a cooling air flow J therebetween).
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 claimed assembly such that the second liner axially overlaps the second portion of the first liner, and wherein a space is formed between the second portion and the second liner, as taught by Pidcock, in order to provide an axial passage between ends of the first and second liner to allow a cooling air flow to pass therethrough, to cool the hot side of the second liner (Pidcock Fig. 6, Col. 4, ln. 45-55, Col. 5, ln. 46-55).
Regarding claim 15, the patent in view of Chang & Pidcock claims the combustor assembly of claim 14, but fails to claim wherein the outer shell includes a first step adjacent to the step of the first liner and a second step adjacent to a location where the second liner axially overlaps the second portion of the first liner.
Pidcock teaches wherein the outer shell 27 includes a first step 22A adjacent to the step 32A of the first liner 29B (Fig. 6 above) and a second step adjacent to a location where the second liner axially overlaps the second portion of the first liner (Fig. 6 above, the outer shell 27 has a step radially outward of where the first and second liners overlap).
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 claimed assembly such that the outer shell includes a first step adjacent to the step of the first liner and a second step adjacent to a location where the second liner axially overlaps the second portion of the first liner, as taught by Pidcock, in order to help direct cooling air flow from between the outer shell and the first and second liners through the space formed between the second portion of the first liner and the second liner.
Claim 21 rejected on the ground of nonstatutory double patenting as being unpatentable over claims 10, 11, 13 of U.S. Patent No. 12,359,816 in view of Chang, further in view of Lockyer (US 6,021,570 A, cited in the 06/24/25 Information Disclosure Statement).
Regarding claim 21, the patent in view of Chang claims the combustor assembly of claim 1, but fails to claim wherein the liner extends circumferentially full hoop about the combustion chamber.
Lockyer teaches the combustor liner 40, 42 can extend circumferentially full hoop about the combustion chamber (Col. 2, ln. 55-57, “Each of the outer and inner liner portions 40,42 are formed from a single unitary sheet into a tube 43 having a generally cylindrical configuration”; Col. 1, ln. 7-9, ln. 43-45)
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 claimed assembly such that the liner extends circumferentially full hoop about the combustion chamber, as taught by Lockyer, in order to provide an annular combustor liner that is formed as one piece, free of seams and not necessitating coupling means to join circumferential sections together, simplifying manufacture and assembly (Lockyer Col. 1, ln. 7-9, ln. 43-45; Col. 2, ln. 55-57). Annular one-piece/full hoop liners are also very well-known in the art for defining an annular combustion chamber.
Claims 16-19 rejected on the ground of nonstatutory double patenting as being unpatentable over claims 10, 11, 13 of U.S. Patent No. 12,359,816 in view of Wilson (US 3,737,152, previously cited in the 08/12/25 Office Action), further in view of Chang.
Regarding independent claim 16, the patent claims a combustor assembly (claim 10, “combustor section having a plurality of combustor assemblies”), comprising:
a combustion chamber defined between a dome assembly and an outlet (claim 10, claim 13, “bulkhead and an outlet”); and
a liner, the liner including a first portion and a second portion extending in a substantially axial direction, the first portion axially forward of the second portion (claim 10, col. 9, ln. 22-29), and
a step connecting the first portion and the second portion (claim 10, Col. 9, ln. 26-27);
wherein the liner is a ceramic matrix composite material (claim 10, col. 9, ln. 30-32);
wherein the step is arranged at an angle to the second portion that is less than 90° such that the step slants axially forward from the second portion to the first portion (claim 11); and
The patent fails to claim wherein the first portion has a first length, the second portion has a second length, the step has a step length, and the first length and the second length are at least twice the step length (the patent does claim this limitation in claim 6, in relation to the embodiment of claim 1); wherein the liner is a unitary ceramic component extending a full length of the combustion chamber between the dome assembly and the outlet; and wherein the liner is not arranged within an outer shell such that the combustion chamber is a single wall combustion chamber.
Wilson teaches a combustor liner having a first portion 11 and a second portion 10 extending in a substantially axial direction (Wilson Fig. 1 & 2), the first portion axially forward of the second portion (Wilson Fig. 2 below, relative to the flow direction A of the cooling air and hot gas), a step 9 connecting the first portion and the second portion (a cooling ring, Col. 2, ln. 31-45); a plurality of slots 13 extending through the step (Wilson Fig. 2 below & Fig. 3); wherein the first portion has a first length L1, the second portion has a second length L2, the step has a step length L3, and the first length and the second length are at least twice the step length (Wilson Fig. 1 below, the lengths of the first and second portion are clearly more than twice the step length).
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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 claimed assembly such that the first portion has a first length, the second portion has a second length, the step has a step length, and the first length and the second length are at least twice the step length, as taught by Wilson, in order to provide a step/intermediate portion through which cooling air flow may egress through the liner in a direction along the length of the second portion, the angle and size of which is selected to best improve cooling of the hot side of the liner by promoting a film of cooling air over the hot side of the liner (Wilson Col. 2, ln. 31-45, ln. 62-Col. 3, ln. 21).
Chang teaches a combustion chamber liner 100 that is a unitary ceramic component (Para. 0047-48, “the liner 100 is a ceramic-based material, such as a ceramic matrix composite (CMC) material… The liner 100 can be formed as a single piece.”) extending a full length of the combustion chamber between a dome assembly 122 and the outlet 108 (Fig. 2, the liner 100 extends across the entire combustion chamber length as shown; Para. 0045, the liner 100 defines the combustion chamber 102; Para. 0053).
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 combustor assembly of the patent in view of Wilson such that the liner is a unitary ceramic component extending a full length of the combustion chamber, as taught by Chang, in order to simplify the manufacture of the liner, forming the entire combustion liner (or at least one of the radially inner or outer liners) as a single piece without seams or joints, or necessitating other attachment/coupling means (Chang Para. 0047-48, 0053).
Wilson further teaches wherein the liner is not arranged within an outer shell such that the combustion chamber is a single wall combustion chamber (Fig. 1 above, the combustor is a single wall combustor as shown, with only the engine casing 7, 8 shown around it).
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 assembly of the patent in view of Wilson & Chang such that the combustor is a single wall combustion chamber without an outer shell, as taught by Wilson, in order to provide a simplified combustor arrangement where compressor discharge air from within the combustor casing effuses directly through the liner into the combustion chamber to cool the combustor (Wilson Col. 2, ln. 17-30). Single walled combustion chambers are well-known and common in the art.
Regarding claim 17, the patent in view of Wilson & Chang claims the combustor assembly of claim 16, and the patent further claims wherein the step joins the second portion at a fillet on an inner side of the liner facing into the combustion chamber (claim 10, col. 9, ln. 26-29).
Regarding claim 18, the patent in view of Wilson & Chang claims the combustor assembly of claim 17, and the patent further claims wherein a step height is defined between the first portion and the second portion and a ratio of a radius of the fillet to the step height is between 0.3 and 0.5 (claim 10, Col. 10, ln. 1-2).
Regarding claim 19, the patent in view of Wilson & Chang claims the combustor assembly of claim 16, but fails to claim wherein the liner is mounted directly to the dome assembly.
Wilson teaches the liner is mounted directly to the dome assembly (Wilson Fig. 1 below).
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 claimed assembly such that the liner is mounted directly to the dome assembly, as taught by Wilson, in order to provide a simplified combustor arrangement where the combustion liner is supported at the forward end by the dome assembly. Such an arrangement is well-known in the art.
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.
Claim 1, 2, 3, 5, 16, 17, & 19 are rejected under 35 U.S.C. 103 as being unpatentable over Wilson in view of Chang.
Regarding independent claim 1, Wilson discloses a combustor assembly 2 (Fig. 1), comprising:
a combustion chamber including a combustion chamber length (Fig. 1 below, Col. 2, ln. 17-21); and
a liner 5, 6 (flame tubes), the liner including:
a first portion 11 and a second portion 10 extending in a substantially axial direction (Fig. 1 & 2), the first portion axially forward of the second portion (Fig. 2, relative to the flow direction A of the cooling air and hot gas),
a step 9 connecting the first portion and the second portion (a cooling ring, Col. 2, ln. 31-45);
a plurality of slots 13 extending through the step (Fig. 2 above & Fig. 3);
wherein the first portion has a first length L1, the second portion has a second length L2, the step has a step length L3, and the first length and the second length are at least twice the step length (Fig. 1 below, the lengths of the first and second portion are clearly more than twice the step length).
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Wilson fails to explicitly disclose wherein the liner is a unitary ceramic component that extends at least 50% of the combustion chamber length.
Chang teaches a combustion chamber liner 100 that is a unitary ceramic component (Para. 0047-48, “the liner 100 is a ceramic-based material, such as a ceramic matrix composite (CMC) material… The liner 100 can be formed as a single piece.”) that extends at least 50% of the combustion chamber length (Fig. 2, the liner 100 extends across the entire combustion chamber length as shown; Para. 0045, the liner 100 defines the combustion chamber 102; Para. 0053).
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 combustor assembly of the Wilson such that the liner is a unitary ceramic component extending at least 50% of the combustion chamber length, as taught by Chang, in order to simplify the manufacture of the liner, forming the entire combustion liner (or at least one of the radially inner or outer liners) as a single piece without seams or joints, or necessitating other attachment/coupling means (Chang Para. 0047-48, 0053). Furthermore, 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. One of ordinary skill in the art would know to select from a variety of known materials (such as a ceramic material) having desired characteristics to achieve a desired level of performance.
Regarding claim 2, Wilson in view of Chang teaches the combustor assembly of claim 1, and Wilson further teaches wherein the step is arranged at an angle to the second portion that is less than 90° such that the step slants axially forward from the second portion to the first portion (Fig. 2, Col. 2, ln. 31-45, “The respective ends of the two adjacent wall sections are disposed at different radii from the axis of the engine so that an intermediate portion 12 of the cooling ring 9, which connects the end portions 10 and 11, lies at an angle to the engine axis. The angle may be as large as 90° but in the example shown it is 40°”).
Regarding claim 3, Wilson in view of Chang teaches the combustor assembly of claim 2, and Wilson further teaches wherein the step 9 joins the second portion 10 at a fillet on an inner side of the liner facing into the combustion chamber (Fig. 2 above, the interface of the step and second portion facing into the combustion chamber is rounded).
Regarding claim 5, Wilson in view of Chang teaches the combustor assembly of claim 2, and Chang further teaches wherein one of the plurality of slots includes an outlet including a perimeter with at least one curve (Fig. 3, the slots 13 are all circular and hence have a perimeter with a curve).
Regarding independent claim 16, Wilson discloses a combustor assembly 2 (Fig. 1), comprising:
a combustion chamber defined between a dome assembly (at the head end in Fig. 1) and an outlet (Fig. 1 below, Col. 2, ln. 17-21); and
a liner 5, 6 (flame tubes), the liner including a first portion 11 and a second portion 10 extending in a substantially axial direction (Fig. 1 & 2), the first portion axially forward of the second portion (Fig. 2, relative to the flow direction A of the cooling air and hot gas), and a step 9 connecting the first portion and the second portion (a cooling ring, Col. 2, ln. 31-45);
wherein the step is arranged at an angle to the second portion that is less than 90° such that the step slants axially forward from the second portion to the first portion (Fig. 2, Col. 2, ln. 31-45, “The respective ends of the two adjacent wall sections are disposed at different radii from the axis of the engine so that an intermediate portion 12 of the cooling ring 9, which connects the end portions 10 and 11, lies at an angle to the engine axis. The angle may be as large as 90° but in the example shown it is 40°”);
wherein the first portion has a first length L1, the second portion has a second length L2, the step has a step length L3, and the first length and the second length are at least twice the step length (Fig. 1 below, the lengths of the first and second portion are clearly more than twice the step length);
wherein the liner is not arranged within an outer shell such that the combustion chamber is a single wall combustion chamber (chamber (Fig. 1 above, the combustor is a single wall combustor as shown, with only the engine casing 7, 8 shown around it).
Wilson fails to disclose wherein the liner is a unitary ceramic component extending a full length of the combustion chamber between the dome assembly and the outlet (Wilson Fig. 1 appears to depict the liner as extending the full length of the combustion chamber but does not explicitly state this).
Chang teaches a combustion chamber liner 100 that is a unitary ceramic component (Para. 0047-48, “the liner 100 is a ceramic-based material, such as a ceramic matrix composite (CMC) material… The liner 100 can be formed as a single piece.”) extending a full length of the combustion chamber between a dome assembly 122 and the outlet 108 (Fig. 2, the liner 100 extends across the entire combustion chamber length as shown; Para. 0045, the liner 100 defines the combustion chamber 102; Para. 0053).
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 combustor assembly of Wilson such that the liner is a unitary ceramic component extending a full length of the combustion chamber, as taught by Chang, in order to simplify the manufacture of the liner, forming the entire combustion liner (or at least one of the radially inner or outer liners) as a single piece without seams or joints, or necessitating other attachment/coupling means (Chang Para. 0047-48, 0053), ceramic materials known for having increased heat-resistance (Chang Para. 0005, 0047). Note, 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. One of ordinary skill in the art would know to select from a variety of known materials (such as a ceramic material) having desired characteristics to achieve a desired level of performance.
Regarding claim 17, Wilson in view of Chang teaches the combustor assembly of claim 16, and Wilson further teaches wherein the step 9 joins the second portion 10 at a fillet on an inner side of the liner facing into the combustion chamber (Wilson Fig. 2 above, the interface of the step and second portion facing into the combustion chamber is rounded).
Regarding claim 19, Wilson in view of Chang teaches the combustor assembly of claim 16, and Wilson further teaches wherein the liner is mounted directly to the dome assembly (Wilson Fig. 1 above, the dome assembly end of the combustor is coupled to the liner).
Claim 4 are rejected under 35 U.S.C. 103 as being unpatentable over Wilson in view of Chang, further in view of Breton (US 4,242,871).
Regarding claim 4, Wilson in view of Chang teaches the combustor assembly of claim 1, but fails to teach wherein a ratio of a height of one of the plurality of slots to a height of the step is greater than 0.66.
Breton teaches a combustor having a liner 10 with a first portion 12, second portion 14, and a step 18 connecting the first and second portions (Breton Fig. 1 below), the step having a plurality of slots 22, 34, each of the step and slots having respective heights h1, h2 (Fig. 4, 5 below), wherein the slots in the step are sized, shaped and grouped to achieve a desired cooling performance, forming a cooling film across the surface of the liner, while controlling a temperature gradient across the step (Breton Col. 2, ln. 40-44, ln. 52-55, “The process selection of slot and hole sizes permits a great deal of latitude in cooling capacity for selecting the cooling desired for a particular application”, Col. 2, ln. 63-65). Therefore the shape and size of the slots is recognized as a result-effective variable. Since the size of the slot is limited by the height of the step that the slot is formed on, a ratio between the slot height and step height is implicitly considered when considering the size of the slot (i.e. the slot height cannot exceed the step height). Consequently the ratio between the slot height and step height can also be considered a result effective variable since the size and shape of the slot is a result-effective variable limited by the size of the step.
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It has been held that optimizing a result effective variable was an obvious extension of prior art teachings, In re Antonie, 559 F.2d 618, 195 USPQ 6 (CCPA 1977). Furthermore, it has been held that “[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation." See In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955), MPEP § 2144.05, II, A. Therefore it would have been obvious to one of ordinary skill in the art at the time the invention was filed to have discovered the optimal ratio of the height of the slot to the height of the step, in the liner of Wilson in view of Gerendas, such as a ratio of greater than 0.66, in order to provide the optimal cooling performance of the slot, providing a desired cooling film and temperature gradient control for the liner (Breton Col. 2, ln. 40-55). Breton teaches a slot having a height that nearly spans the height of the step (Breton Fig. 2 above clearly shows that the height of the slot h1 is roughly 3/4ths the height of the step h2; Fig. 3 & 4 also shows the slot height being a majority of the step height), but does not explicitly state the height of the slot. However, one skilled in the art would know to modify the slot size of a slot positioned within a step of the liner to achieve a desired cooling effectiveness based on the teachings of Breton, within the limits of the step height. The ratio of the height of the slot to the height of the step are inherently linked, as the step height represents an upper limit of the height of the slot. Consequently, optimizing the slot height would also optimize the ratio between the slot height and step height, for instance, resulting in a ratio that can be greater than 0.66 if the height of the slot is nearly the same size as the height of the step (which would represent a ratio approaching 1.0). One skilled in the art would seek a slot-to-step height ratio approaching 1.0 for example, if it was desired to provide more cooling air flow through the slot.
Claim 6-10, 12-15 are rejected under 35 U.S.C. 103 as being unpatentable over Wilson in view of Chang, further in view of Pidcock.
Regarding claim 6 & 7, the Wilson in view of Chang teaches the combustor assembly of claim 1, but fails to teach wherein the liner is arranged within an outer shell such that a gap is formed between the outer shell and the liner; wherein the gap is configured to receive cooling airflow, and wherein the plurality of slots are configured to communicate the cooling airflow from an outer side of the liner to an inner side of the liner facing into the combustion chamber.
Pidcock teaches a combustor assembly having a liner 29B that is arranged within an outer shell 27 (outer wall) such that a gap 44 is formed between the outer shell and the liner (Pidcock Fig. 6 below); and wherein the gap 44 is configured to receive cooling airflow (via holes 42 in the outer shell 27, Col. 5, ln. 8-11), and wherein the plurality of slots 46 are configured to communicate the cooling airflow from an outer side of the liner to an inner side of the liner facing into the combustion chamber (Col. 5, ln. 12-17, ln. 46-55).
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 assembly of Wilson in view of Chang, the outer shell with gap between the shell and liner to receive cooling airflow that is communicated from an outer side of the liner to an inner side of the liner, as taught by Pidcock, in order to improve the cooling of the combustion liner by having an impingement cooling liner/shell directing cooling flow towards the combustion liner, and using the plurality of slots to promote film cooling of the hot side of the liner (Pidcock Col. 5, ln. 8-17, ln. 46-55).
Regarding claim 8, Wilson in view of Chang & Pidcock teaches the combustor assembly of claim 7, and Wilson further teaches the plurality of slots 13 are configured to communicate the cooling airflow in a direction substantially parallel to an inner surface of the second portion 10 (Wilson Fig. 2 above, the airflow exiting the slots 13 would be swept in a downstream direction by the upstream flow passing along the interior surface of the first portion 11, and would thus flow parallel to the inner surface of the second portion).
Regarding claim 9, 10, Wilson in view of Chang & Pidcock teaches the combustor assembly of claim 6, but fails to claim wherein the outer shell includes a step adjacent to the step of the liner; wherein the step of the liner is arranged axially aft of the step of the outer shell.
Pidcock further teaches wherein the outer shell 27 includes a step 22A adjacent to the step of the liner (Fig. 6, the step in the liner where the slots 46 are formed); and wherein the step 32A of the liner is arranged axially aft of the step 22A of the outer shell 27 (Fig. 6, relative to the flow direction of cooling air through the outer shell and through the liner).
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 assembly of Wilson in view of Chang & Pidcock such that the outer shell includes a step adjacent the step of the liner; of the step of the liner being arranged axially aft of the step of the outer shell, as taught by Pidcock, in order to conform the shape of the outer shell to the shape of the liner and help direct the cooling air flow through the gap between the liner and outer shell.
Regarding claim 12, Wilson in view of Chang & Pidcock teaches the combustor assembly of claim 6, but fails to claim wherein the outer shell is secured to a dome assembly at a location axially forward of the first portion, and wherein the liner is secured to the outer shell.
Pidcock teaches wherein the outer shell 27 is secured to a dome assembly 26 at a location axially forward of the first portion (Fig. 2), and wherein the liner is secured to the outer shell (via threaded plugs 34 and nuts 36, Fig. 2, Col. 4, ln. 56-60).
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 assembly of Wilson in view of Chang & Pidcock such that the outer shell is secured to a dome assembly forward of the first portion and the liner being secured to the outer shell, as taught by Pidcock, in order to secure the liner and outer shell to the overall combustor assembly. Having a dome assembly with the outer shell secured thereto is well-known in the art, as is having the combustor liner portions secured to an outer shell.
Regarding claim 13, Wilson in view of Chang & Pidcock teaches the combustor assembly of claim 6, but fails to claim wherein the liner is a first liner and further comprising a second liner extending axially aft of the first liner.
Pidcock teaches wherein the liner 29B is a first liner (Fig. 6) and further comprising a second liner 29A extending axially aft of the first liner (Fig. 6 below, there is another liner 29A downstream of the first liner as shown).
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 assembly of Wilson in view of Chang & Pidcock to include a second liner extending axially aft of the first liner, as taught by Pidcock, in order to provide additional combustion liner wall elements for protecting additional sections of the combustor downstream of the first portion (Pidcock Col. 4, ln. 45-55, Col. 5, ln. 46-55).
Regarding claim 14, Wilson in view of Chang & Pidcock teaches the combustor assembly of claim 13, but fails to claim wherein the second liner axially overlaps the second portion of the first liner, and wherein a space is formed between the second portion and the second liner.
Pidcock teaches wherein the second liner 29A axially overlaps the second portion 32_2 of the first liner (Fig. 6 below, the ends 30, 31 of the second and first liners overlap axially as shown), and wherein a space is formed between the second portion and the second liner (a radial gap between the edges 30, 31 of the second liner and first liner as shown, for issuing a cooling air flow J therebetween).
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 assembly of Wilson in view of Chang & Pidcock such that the second liner axially overlaps the second portion of the first liner, and wherein a space is formed between the second portion and the second liner, as taught by Pidcock, in order to provide an axial passage between ends of the first and second liner to allow a cooling air flow to pass therethrough, to cool the hot side of the second liner (Pidcock Fig. 6, Col. 4, ln. 45-55, Col. 5, ln. 46-55).
Regarding claim 15, Wilson in view of Chang & Pidcock teaches the combustor assembly of claim 14, but fails to claim wherein the outer shell includes a first step adjacent to the step of the first liner and a second step adjacent to a location where the second liner axially overlaps the second portion of the first liner.
Pidcock teaches wherein the outer shell 27 includes a first step 22A adjacent to the step 32A of the first liner 29B (Fig. 6 above) and a second step adjacent to a location where the second liner axially overlaps the second portion of the first liner (Fig. 6 above, the outer shell 27 has a step radially outward of where the first and second liners overlap).
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 assembly of Wilson in view of Chang & Pidcock such that the outer shell includes a first step adjacent to the step of the first liner and a second step adjacent to a location where the second liner axially overlaps the second portion of the first liner, as taught by Pidcock, in order to help direct cooling air flow from between the outer shell and the first and second liners through the space formed between the second portion of the first liner and the second liner.
Claim 21 is rejected under 35 U.S.C. 103 as being unpatentable over Wilson in view of Chang, further in view of Lockyer.
Regarding claim 21, Wilson in view of Chang teaches the combustor assembly of claim 1, but fails to claim wherein the liner extends circumferentially full hoop about the combustion chamber.
Lockyer teaches the combustor liner 40, 42 can extend circumferentially full hoop about the combustion chamber (Col. 2, ln. 55-57, “Each of the outer and inner liner portions 40,42 are formed from a single unitary sheet into a tube 43 having a generally cylindrical configuration”; Col. 1, ln. 7-9, ln. 43-45)
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 assembly of Wilson in view of Chang such that the liner extends circumferentially full hoop about the combustion chamber, as taught by Lockyer, in order to provide an annular combustor liner that is formed as one piece, free of seams and not necessitating coupling means to join circumferential sections together, simplifying manufacture and assembly (Lockyer Col. 1, ln. 7-9, ln. 43-45; Col. 2, ln. 55-57). Annular one-piece/full hoop liners are also very well-known in the art for defining an annular combustion chamber.
Allowable Subject Matter
Claim 11 is allowed.
Claims 18 is 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, and a timely filed Terminal Disclaimer submitted to overcome the non-statutory double patenting rejection presented above.
Response to Arguments
Applicant’s arguments with respect to claims 1-10, 12-19, 21 have been considered but are moot in view of the new ground(s) 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.
Conclusion
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).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
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/ALAIN CHAU/Primary Examiner, Art Unit 3741