Prosecution Insights
Last updated: April 19, 2026
Application No. 18/420,982

BRUSH SEAL FOR A TURBOMACHINE

Final Rejection §103
Filed
Jan 24, 2024
Examiner
HTAY, AYE SU MON
Art Unit
3745
Tech Center
3700 — Mechanical Engineering & Manufacturing
Assignee
MTU Aero Engines AG
OA Round
2 (Final)
67%
Grant Probability
Favorable
3-4
OA Rounds
3y 4m
To Grant
96%
With Interview

Examiner Intelligence

Grants 67% — above average
67%
Career Allow Rate
238 granted / 355 resolved
-3.0% vs TC avg
Strong +28% interview lift
Without
With
+28.5%
Interview Lift
resolved cases with interview
Typical timeline
3y 4m
Avg Prosecution
27 currently pending
Career history
382
Total Applications
across all art units

Statute-Specific Performance

§101
0.9%
-39.1% vs TC avg
§103
40.5%
+0.5% vs TC avg
§102
30.2%
-9.8% vs TC avg
§112
27.1%
-12.9% vs TC avg
Black line = Tech Center average estimate • Based on career data from 355 resolved cases

Office Action

§103
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 . Response to Arguments Applicant’s arguments with respect to independent claim 11 have been considered but are 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. 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. 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 11, 16-21, and 23 are rejected under 35 U.S.C. 103 as being unpatentable over Cernay et al. (US 20150084285, hereinafter: “Cernay”) in view of Davis (US 20200103036). In reference to Claim 11 Cernay discloses: A brush seal (10) for a turbomachine (Abstract, [0001-0002]), comprising: a bristle package (16) made of a metal or a metal alloy [0005], wherein the bristle package includes a plurality of wires (12, 14) combined to form the bristle package [0014-0015], the plurality of wires being fixed around a core wire (20) in a clamping tube (22) [0017-0018]. (Fig. 1-2) Cernay discloses a bristle package (16) made of a metal or a metal alloy [0005]; however, Cernay is silent on the specific metal alloy such as Ni-based alloy. Davis teaches: A brush seal (84) for a turbomachine, comprising: a bristle package made of a Ni-based alloy [0047-0050] (Fig. 1-9). Based on the teaching of Davis and Miyashita, it would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify the bristle package of Cernay by constructing them using the nickel-based alloy material as taught by Davis for the purpose of utilizing a well-known material for a bristle package. In reference to Claim 16 Cernay as modified by Davis discloses: Cernay discloses a turbomachine comprising the brush seal as recited in claim 11. (Abstract; [0001-0005] (Fig. 1-2, Cernay). In reference to Claim 17 Cernay as modified by Davis discloses: Cernay discloses the turbomachine as recited in claim 16 wherein the turbomachine is configured as a gas turbine [0002] (Fig. 1-2, Cernay). In reference to Claim 18 Cernay as modified by Davis discloses: Cernay discloses the turbomachine as recited in claim 17 wherein the gas turbine is an aircraft gas turbine. [0002] (Fig. 1-2, Cernay). In reference to Claim 19 Cernay as modified by Davis discloses: Cernay discloses the turbomachine as recited in claim 17 wherein the gas turbine is an industrial gas turbine.(“Fields of application for the brush seal according to the invention particularly relate to application in aircraft engines, industrial gas turbines, steam turbines, industrial compressors, or also many other engineering applications,” [0005, Cernay]. In reference to Claim 20 Cernay as modified by Davis discloses: Cernay discloses the turbomachine as recited in claim 16 wherein turbomachine is configured as a steam turbine. (“Fields of application for the brush seal according to the invention particularly relate to application in aircraft engines, industrial gas turbines, steam turbines, industrial compressors, or also many other engineering applications,” [0005, Cernay]. In reference to Claim 21 Cernay as modified by Davis discloses: Davis teaches a method for manufacturing a brush seal (84) comprising providing a bristle package made of a Ni-based alloy [0048-0049, Davis]. In reference to Claim 23 Cernay as modified by Davis discloses: The brush seal as recited in claim 11. Cernay discloses the plurality of wires (12, 14, 16) are fixed around the core wire (20) to have ends in a same plane (ends of wires 16 as shown in Fig. 2 of Cernay). [0018]. Claims 14, and 22 are rejected under 35 U.S.C. 103 as being unpatentable over Cernay et al. (US 20150084285, hereinafter: “Cernay”) in view of Davis (US 20200103036) as applied to claims 11 and 21 above, and further in view of Miyashita et al. (EP 2835434, hereinafter: “Miyashita”). In reference to Claim 14 Cernay as modified by Davis discloses: The brush seal as recited in claim 11. Cernay as modified by Davis discloses the bristle package made of a Ni-based alloy [0047-0050, Davis] (Fig. 1-9, Davis). Davis is silent on the composition of the Ni-based alloy. Miyashita teaches Ni-based alloy which is used to manufacture turbine components [0001-0008]. Miyashita teaches the Ni-based alloy of the bristle package contains the following chemical elements: 7 % to 16 % Co, 17 % to 26 % Cr, 5 % to 13 % Mo, up to 5 % Ti, and up to 5 % Al, all percentages given above being in mass %, with a remainder of the alloy being Ni and inevitable impurities (Table 1, Sample 1). [0087-0088]. Based on the teaching of Miyashita and Cernay as modified by Davis, it would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify the brush seal of Cernay as modified by Davis by utilizing the Ni-based alloy material as taught by Miyashita for the purpose of utilizing a material for a component of a turbine used under a high-temperature environment [0008, Miyashita]. In reference to Claim 22 Cernay as modified by Davis discloses: The brush seal as recited in claim 21. Cernay as modified by Davis discloses the bristle package made of a Ni-based alloy [0047-0050, Davis] (Fig. 1-9, Davis). Davis is silent on the composition of the Ni-based alloy. Miyashita teaches Ni-based alloy which is used to manufacture turbine components and methods of manufacturing the Ni-based alloy. Miyashita discloses step of heat treatment to harden the Ni-based alloy. [0069-0073]. Based on the teaching of Miyashita and Cernay as modified by Davis, it would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify the brush seal of Cernay as modified by Davis by utilizing the Ni-based alloy material and steps of manufacturing it which includes a heat treatment as taught by Miyashita for the purpose of utilizing a material for a component of a turbine used under a high-temperature environment [0008, Miyashita]. 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 AYE SU MON HTAY whose telephone number is (571)270-5958. The examiner can normally be reached Monday-Friday, 9:00am-3:00pm PST. Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice. If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Nathan Wiehe can be reached at 571-272-8648. 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. /AYE S HTAY/Examiner, Art Unit 3745 /NATHANIEL E WIEHE/Supervisory Patent Examiner, Art Unit 3745
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Prosecution Timeline

Jan 24, 2024
Application Filed
Jun 14, 2025
Non-Final Rejection — §103
Sep 18, 2025
Response Filed
Jan 02, 2026
Final Rejection — §103 (current)

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Study what changed to get past this examiner. Based on 5 most recent grants.

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Prosecution Projections

3-4
Expected OA Rounds
67%
Grant Probability
96%
With Interview (+28.5%)
3y 4m
Median Time to Grant
Moderate
PTA Risk
Based on 355 resolved cases by this examiner. Grant probability derived from career allow rate.

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