Prosecution Insights
Last updated: April 19, 2026
Application No. 19/045,180

BURNER ASSEMBLY, GAS TURBINE COMBUSTOR, AND GAS TURBINE

Final Rejection §102§103§112
Filed
Feb 04, 2025
Examiner
LIU, JINGCHEN
Art Unit
3741
Tech Center
3700 — Mechanical Engineering & Manufacturing
Assignee
Mitsubishi Heavy Industries Ltd.
OA Round
2 (Final)
59%
Grant Probability
Moderate
3-4
OA Rounds
2y 7m
To Grant
99%
With Interview

Examiner Intelligence

Grants 59% of resolved cases
59%
Career Allow Rate
51 granted / 87 resolved
-11.4% vs TC avg
Strong +62% interview lift
Without
With
+62.0%
Interview Lift
resolved cases with interview
Typical timeline
2y 7m
Avg Prosecution
33 currently pending
Career history
120
Total Applications
across all art units

Statute-Specific Performance

§101
0.5%
-39.5% vs TC avg
§103
48.1%
+8.1% vs TC avg
§102
14.1%
-25.9% vs TC avg
§112
36.2%
-3.8% vs TC avg
Black line = Tech Center average estimate • Based on career data from 87 resolved cases

Office Action

§102 §103 §112
Detailed Action Notice of Pre-AIA or AIA Status The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA . Claim Objections Claim 3 is objected to because of the following informalities: Regarding claim 3, the recitation “wherein a passage wall forming the mixing passage of the first burner and a passage wall forming the mixing passage of the second burner share a partition portion that separates the mixing passage of the first burner from the mixing passage of the second burner” is believed to be in error for - - wherein a passage wall of the flow path of the first burner forming the mixing passage of the first burner and a passage wall of the flow path of the second burner forming the mixing passage of the second burner share a partition portion that separates the mixing passage of the first burner from the mixing passage of the second burner - - 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. Claim 4 is 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 applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention. Regarding claim 4, recitation “wherein, when a cross-section of the partition portion passing through center of the inlet of the mixing passage of the first burner and center of the inlet of the mixing passage of the second burner and taken along a central axis of the mixing passage of the first burner is defined as a first cross-section” is indefinite because terms “the inlet of the mixing passage” lack antecedent basis and it is unclear whether said terms refer to i) the inlet of the flow path preciously claimed in claim 1; or ii) a different inlet. Claim Rejections - 35 USC § 102 In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status. The following is a quotation of 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. Claims 1 and 7-8 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Gubba 20180328587. Regarding claim 1, Gubba teaches the invention as claimed: A burner assembly (an axial fuel staging system 200, Fig. 1), comprising a plurality of burners (100s, Fig. 1) for mixing fuel and air, wherein each of the plurality of burners (each 100s) includes: at least one fuel nozzle (340, Figs. 2 and 4) for injecting the fuel (via holes 354, see Fig. 2 and [0052]); and a flow path (comprising walls 362s, see Fig. 4) forming a mixing passage (annotated Fig. 4) into which the fuel injected from (via holes 354) the at least one fuel nozzle (340, see Fig. 2 and [0052]) and the air (36 in Fig. 1) are introduced from an inlet (annotated Fig. 4) of the flow path (comprising walls 362s, see Fig. 4), wherein, in an axial view (an axial cross-section as shown in Fig. 4) of the mixing passage from an upstream side of the mixing passage (annotated Fig. 4), the at least one fuel nozzle (340) for supplying the fuel to the mixing passage (annotated Fig. 4) is disposed around the periphery of the mixing passage (the periphery of walls 362s in Fig. 4) so as not to overlap with the mixing passage (because nozzle 340 is located axially above and radially outward from the inlet of the flow path, see annotated Fig. 4), wherein the at least one fuel nozzle (340) includes a protruding portion (annotated Fig. 4) protruding upstream of the inlet of the flow path in a flow direction of the air (see annotated Fig. 4) and at least one fuel injection hole (354) formed on a side surface (348) of the protruding portion (annotated Fig. 4), and wherein a top surface (342) of the protruding portion (annotated Fig. 4), which is the upstream end surface (342) of the protruding portion (annotated Fig. 4) in the flow direction of the air (annotated Fig. 4), includes a convex curved surface (342 is a convex curved surface, see Fig. 4). PNG media_image1.png 999 1210 media_image1.png Greyscale Regarding claim 7, Gubba further teaches A gas turbine combustor (10, see Fig. 1 and [0028]), comprising: the burner assembly (the axial fuel staging system 200, Fig. 1); and a combustion liner (12) forming a space (60) in which a flame (generated by the combustion of the mixture of fuel and air 56, see Fig. 1) is formed downstream (related to the flow direction of air 36 through the plurality of burners 100s) of the burner assembly (the axial fuel staging system 200, Fig. 1). Regarding claim 8, Gubba further teaches A gas turbine (the gas turbine engine per [0028 ]), comprising: a compressor (the compressor per [0028]); a gas turbine combustor (10 in Fig. 1) configured to be supplied with air (36) compressed by the compressor (see [0028]) and fuel (supplied by fuel supply line 104, see Fig. 1 and [0035]), and produce a combustion gas by combusting the fuel (see Fig. 1 and [0029]); and a turbine (the turbine per [0028]) driven by the combustion gas produced by the gas turbine combustor (see [0028-0029]), wherein the gas turbine combustor is the gas turbine combustor (10, Fig. 1). Claim Rejections - 35 USC § 103 In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status. The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action: A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made. The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows: 1. Determining the scope and contents of the prior art. 2. Ascertaining the differences between the prior art and the claims at issue. 3. Resolving the level of ordinary skill in the pertinent art. 4. Considering objective evidence present in the application indicating obviousness or nonobviousness. Claims 1 and 3-4 are rejected under 35 U.S.C. 103 as being unpatentable over Barkowski 20100323309 in view of Baumann 20170198914. Regarding claim 1, Barkowski teaches the invention as claimed: A burner assembly (1, Fig. 1), comprising a plurality of burners (2s) for mixing fuel (17) and air (10, see Fig. 9 and [0054 and 0060]), wherein each of the plurality of burners (each 2) includes: at least one fuel nozzle (20) for injecting the fuel (17, see Fig. 9); and a flow path (having inlet 8 and outlet 9, see Fig. 9) forming a mixing passage (annotated Fig. 9) into which the fuel (17) injected from the at least one fuel nozzle (20) and the air (10) are introduced from an inlet (8) of the flow path (per [0021], the nozzle 20 may be disposed in the inlet 8 as shown in Fig. 9 or immediately upstream from the inlet 8 in Fig. 9), wherein, in an axial view (the cross-sectional view as shown in Fig. 9) of the mixing passage (annotated Fig. 9) from an upstream side (annotated Fig. 9) of the mixing passage, the at least one fuel nozzle (20) for supplying the fuel (17) to the mixing passage (annotated Fig. 9) is disposed around the periphery (an inner periphery, see annotated Fig. 9) of the mixing passage so as not to overlap with the mixing passage (because, relative to the axis 5 in Fig. 9, the fuel nozzle 20 marked in annotated Fig. 9 is axially and radially offset from the portion of the mixing passage marked in annotated Fig. 9), wherein the at least one fuel nozzle (20) includes a protruding portion (the body of 20) protruding upstream (because the body of 20 has an axial height) of the inlet (8) of the flow path in a flow direction of the air (flow direction of 10, see Fig. 9) and at least one fuel injection hole (where fuel 17 is injected from 20). PNG media_image2.png 633 961 media_image2.png Greyscale Barkowski does not teach at least one fuel injection hole formed on a side surface of the protruding portion, and wherein a top surface of the protruding portion, which is the upstream end surface of the protruding portion in the flow direction of the air, includes a convex curved surface. However, Baumann teaches at least one fuel nozzle (42, see Figs. 13B and 14G) includes a protruding portion (the body of 42, see Figs. 13B and 14G) protruding upstream (because the body of 42 has an axial height, see Fig. 14G) in a flow direction of the air (flow direction of 20, see Fig. 14G) and at least one fuel injection hole (4) formed on a side surface (a bottom side surface, see annotated Fig. 14G) of the protruding portion (the body of 42), and wherein a top surface (annotated Fig. 14G) of the protruding portion (the body of 42), which is the upstream end surface of the protruding portion in the flow direction of the air (the flow direction of 20, see Fig. 14G), includes a convex curved surface (at the rounding corner of the top surface, see annotated Fig. 14G and [0081]). PNG media_image3.png 452 686 media_image3.png Greyscale It would have been obvious to one of ordinary skill in the art before the effective filling date of the claimed invention to modify Barkowski with Baumann’s protruding portion, such that at least one fuel injection hole formed on a side surface of the protruding portion, and wherein a top surface of the protruding portion, which is the upstream end surface of the protruding portion in the flow direction of the air, includes a convex curved surface (the modification is to modify the shape of Barkowski’s protruding portion to the shape of Baumann’s protruding portion) in order to intensify and improve mixing effect based on high turbulence by injecting fuel into the vortices substantially tangentially with respect to the vortex street (Baumann, [0082 and 0011]). Regarding claim 3, Barkowski further teaches wherein the plurality of burners includes a first burner (annotated Fig. 1), and a second burner (annotated Fig. 1) having the mixing passage (formed by the flow path having inlet 8 and outlet 9, see Fig. 9) that is closest to the mixing passage of the first burner (because the first burner and the second burner are located adjacent to each other without additional burner disposed therebetween, see annotated Figs. 1 and 9), wherein a passage wall (the portion of housing 6 that forming the first burner) forming the mixing passage of the first burner (see annotated Fig. 1) and a passage wall (the portion of housing 6 that forming the first burner) forming the mixing passage of the second burner (see annotated Fig. 1) share a partition portion (annotated Figs. 1 and 9) that separates the mixing passage of the first burner from the mixing passage of the second burner (see annotated Figs. 1 and 9), and wherein a thickness (annotated Fig. 9) of the partition portion decreases (see annotated Fig. 9) upstream in the flow direction of the air (the flow direction of 10) in an upstream end portion (the largened portion in annotated Fig. 9) of the partition portion in the flow direction of the air. PNG media_image4.png 463 730 media_image4.png Greyscale PNG media_image5.png 747 992 media_image5.png Greyscale Regarding claim 4, Barkowski further teaches wherein, when a cross-section (C-C, see annotated Fig. 1) of the partition portion (annotated Figs. 1 and 9) passing through center (annotated Fig. 1) of the inlet (8) of the mixing passage (annotated Fig. 9) of the first burner (annotated Figs. 1 and 9) and center (annotated Fig. 1) of the inlet (8) of the mixing passage (annotated Fig. 9) of the second burner (annotated Figs. 1 and 9) and taken along a central axis (annotated Fig. 9) of the mixing passage of the first burner (annotated Fig. 9) is defined as a first cross-section (the C-C taken as shown in annotated Fig. 1 results a cross-sectional view as shown in annotated Fig. 9), an upstream end surface of the partition portion in the flow direction of the air includes a convex curved line (annotated Fig. 9) in the first cross-section (the cross-sectional view as shown in annotated Fig. 9). PNG media_image6.png 495 760 media_image6.png Greyscale PNG media_image7.png 747 992 media_image7.png Greyscale Allowable Subject Matter Claims 2 and 5-6 are allowed. REASONS FOR ALLOWANCE The following is an examiner’s statement of reasons for allowance. Regarding claim 2, the prior arts of record itself or in combination does not teach in combination with the other limitations of claim 2, “… wherein the plurality of burners includes a first burner, and a second burner having the mixing passage that is closest to the mixing passage of the first burner, wherein the mixing passage of the first burner and the mixing passage of the second burner are separated by a partition portion, wherein, in an axial view of the mixing passage from an upstream side of the mixing passage, the at least one fuel nozzle for supplying the fuel to the mixing passage is disposed radially outward of the mixing passage, wherein the at least one fuel nozzle includes a protruding portion protruding upstream of the inlet of the flow path in a flow direction of the air, …”. Regarding claim 5, the prior arts of record itself or in combination does not teach in combination with the other limitations of claim 5, “… wherein the protruding portion of the first fuel nozzle is disposed adjacent to the partition portion, wherein the protruding portion of the second fuel nozzle is disposed adjacent to the partition portion on an opposite side of a plane including the first cross-section from the protruding portion of the first fuel nozzle, and wherein a height of the partition portion increases as approaching the protruding portion of the first fuel nozzle from the first cross-section”. Claim 6 is allowable because claim 6 depends on the allowable independent claim 5. Any comments considered necessary by applicant must be submitted no later than the payment of the issue fee and, to avoid processing delays, should preferably accompany the issue fee. Such submissions should be clearly labeled “Comments on Statement of Reasons for Allowance.” Response to Arguments Applicant’s arguments with respect to claim 1 has been considered but is moot because the new ground of rejection does not rely on any reference applied in the prior rejection of record for any teaching or matter specifically challenged in the argument. 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. Any inquiry concerning this communication or earlier communications from the examiner should be directed to JINGCHEN LIU whose telephone number is (571)272-6639. The examiner can normally be reached 9:30-4:30. Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice. If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Devon Kramer can be reached at (571) 272-7118. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300. Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000. /JINGCHEN LIU/Examiner, Art Unit 3741 /DEVON C KRAMER/Supervisory Patent Examiner, Art Unit 3741
Read full office action

Prosecution Timeline

Feb 04, 2025
Application Filed
Nov 20, 2025
Non-Final Rejection — §102, §103, §112
Jan 28, 2026
Applicant Interview (Telephonic)
Jan 28, 2026
Examiner Interview Summary
Feb 10, 2026
Response Filed
Feb 24, 2026
Examiner Interview (Telephonic)
Mar 02, 2026
Final Rejection — §102, §103, §112 (current)

Precedent Cases

Applications granted by this same examiner with similar technology

Patent 12601488
PREMIXER ARRAY
2y 5m to grant Granted Apr 14, 2026
Patent 12601303
ENGINE SYSTEM AND METHOD OF OPERATING THE SAME
2y 5m to grant Granted Apr 14, 2026
Patent 12571536
MULTI-WALLED STRUCTURE FOR A GAS TURBINE ENGINE
2y 5m to grant Granted Mar 10, 2026
Patent 12560123
ARCUATE FUEL GALLERY FOR TURBINE ENGINE FUEL NOZZLE
2y 5m to grant Granted Feb 24, 2026
Patent 12553364
MAGNET ANTI-ICE SYSTEM
2y 5m to grant Granted Feb 17, 2026
Study what changed to get past this examiner. Based on 5 most recent grants.

AI Strategy Recommendation

Get an AI-powered prosecution strategy using examiner precedents, rejection analysis, and claim mapping.
Powered by AI — typically takes 5-10 seconds

Prosecution Projections

3-4
Expected OA Rounds
59%
Grant Probability
99%
With Interview (+62.0%)
2y 7m
Median Time to Grant
Moderate
PTA Risk
Based on 87 resolved cases by this examiner. Grant probability derived from career allow rate.

Sign in with your work email

Enter your email to receive a magic link. No password needed.

Personal email addresses (Gmail, Yahoo, etc.) are not accepted.

Free tier: 3 strategy analyses per month