Prosecution Insights
Last updated: April 18, 2026
Application No. 18/581,539

HONEYCOMB STRUCTURE FOR HEAT EXCHANGER AND HEAT EXCHANGER

Final Rejection §103
Filed
Feb 20, 2024
Examiner
TRAN, LEN
Art Unit
3763
Tech Center
3700 — Mechanical Engineering & Manufacturing
Assignee
NGK Insulators Ltd.
OA Round
2 (Final)
11%
Grant Probability
At Risk
3-4
OA Rounds
2y 8m
To Grant
32%
With Interview

Examiner Intelligence

Grants only 11% of cases
11%
Career Allow Rate
12 granted / 113 resolved
-59.4% vs TC avg
Strong +21% interview lift
Without
With
+21.3%
Interview Lift
resolved cases with interview
Typical timeline
2y 8m
Avg Prosecution
18 currently pending
Career history
131
Total Applications
across all art units

Statute-Specific Performance

§103
49.3%
+9.3% vs TC avg
§102
25.0%
-15.0% vs TC avg
§112
22.6%
-17.4% vs TC avg
Black line = Tech Center average estimate • Based on career data from 113 resolved cases

Office Action

§103
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 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 1-6 are rejected under 35 U.S.C. 103 as being unpatentable over document JP 5872178 B2 (herein referred to as ‘178). Regarding claim1, ‘178 discloses a honeycomb structure for a heat exchanger, the honeycomb structure comprising: an inner peripheral wall 8; an outer peripheral wall 3; and partition walls 7 disposed between the inner peripheral wall and the outer peripheral wall, the partition walls defining cells 5 each extending from a first end face to a second end face (see Fig. 6)., wherein, in a cross section orthogonal to an extending direction of the cells, the partition walls comprise one or more first partition walls extending in a radial direction. ‘178 does not disclose the diameters or the opening ratio as recited, however, since the prior art discloses the structure of the device, the recited diameters and the opening ratio would have involved a mere change in the size of a component which is generally recognized as being within the level of ordinary skill in the art. Regarding claim 2, the recited one or more second partition walls would have involved duplication of working parts of a device, which is generally recognized as being within the level of ordinary skill in the art when the device will still carry its intended tasks with the modification. Regarding claims 3-6, the opening ratios would have involved a mere change in the size of a component as stated above. Regarding claims 7 and 8, ‘178 discloses a heat exchanger comprising the recited honeycomb structure. Response to Arguments Applicant's arguments filed 12/12/2025 have been fully considered but they are not persuasive. Applicant argues on page 2 that JP ‘178 fails to teach the inner diameter of the asserted peripheral wall, and the opening ratio of the honeycomb structure. While the examiner agrees that JP ‘178 fails to teach the claimed range, the claim is not patentable over the teaching of JP ‘178. As explained on page 4 of JP ‘178 (translation), the diameter and the thickness of these walls are for reducing the chances of cracks. Furthermore, JP ’178 six examples of different parameters, in which the concerns of thickness, diameter, and openings are similar to applicant’s invention. Therefore, it would have been obvious to one of ordinary skill in the art to arrive to applicant’s inner and outer diameter claimed range as well as the opening ratio, since this would merely involve routine experimentation to find an optimal result. Conclusion THIS ACTION IS MADE FINAL. 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 Len Tran whose telephone number is (571)272-1184. The examiner can normally be reached Monday-Friday, 8am - 4pm. 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. 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. /LEN TRAN/Supervisory Patent Examiner, Art Unit 3763
Read full office action

Prosecution Timeline

Feb 20, 2024
Application Filed
Sep 22, 2025
Non-Final Rejection — §103
Dec 12, 2025
Response Filed
Apr 07, 2026
Final Rejection — §103 (current)

Precedent Cases

Applications granted by this same examiner with similar technology

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Patent 12496477
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Patent 12478993
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2y 5m to grant Granted Nov 25, 2025
Patent 9545479
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2y 5m to grant Granted Jan 17, 2017
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
11%
Grant Probability
32%
With Interview (+21.3%)
2y 8m
Median Time to Grant
Moderate
PTA Risk
Based on 113 resolved cases by this examiner. Grant probability derived from career allow rate.

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