Prosecution Insights
Last updated: April 19, 2026
Application No. 18/334,172

SELF-REGULATING AND GRAVITY-INDEPENDENT DEVICE FOR HYDROGEN RECOMBINING WITH AN INTEGRATED PASSIVE HEAT SINK FOR LOW-EARTH ORBIT AND DEEP-SPACE EXPLORATION SPACECRAFT

Non-Final OA §102§103
Filed
Jun 13, 2023
Examiner
ARANT, HARRY E
Art Unit
3763
Tech Center
3700 — Mechanical Engineering & Manufacturing
Assignee
Hamilton Sundstrand Corporation
OA Round
1 (Non-Final)
48%
Grant Probability
Moderate
1-2
OA Rounds
3y 9m
To Grant
71%
With Interview

Examiner Intelligence

Grants 48% of resolved cases
48%
Career Allow Rate
274 granted / 569 resolved
-21.8% vs TC avg
Strong +22% interview lift
Without
With
+22.4%
Interview Lift
resolved cases with interview
Typical timeline
3y 9m
Avg Prosecution
49 currently pending
Career history
618
Total Applications
across all art units

Statute-Specific Performance

§101
0.1%
-39.9% vs TC avg
§103
55.0%
+15.0% vs TC avg
§102
26.2%
-13.8% vs TC avg
§112
17.3%
-22.7% vs TC avg
Black line = Tech Center average estimate • Based on career data from 569 resolved cases

Office Action

§102 §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 . 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. Claim(s) 1-4, 9-14, and 19-20 is/are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Broeckerhoff et al. (European Patent Publication EP1314166B1, “Broeckerhoff”). Regarding claim 1, Broeckerhoff discloses a hydrogen recombiner (fig 1) assembly comprising: a hydrogen recombiner integrated with a passive heat sink (7), the passive heat sink comprising a heat transfer working fluid (¶0020), and the hydrogen recombiner comprising a catalyst (8, ¶0021); and wherein the hydrogen recombiner is configured to convert leaked hydrogen to water vapor (¶0002-0003). Regarding claim 2, Broeckerhoff further discloses wherein the hydrogen recombiner is a flameless hydrogen recombiner (as evident in fig 1). Regarding claim 3, Broeckerhoff further discloses wherein the catalyst comprises a platinum catalyst (¶0005). Regarding claim 4, Broeckerhoff further discloses wherein the passive heat sink (7) comprises an evacuated metallic cylindrical tube (as evident in fig 3) that is sealed and filled with the heat transfer working fluid (¶0020), with the heat transfer working fluid configured to flow in an annular space of the passive heat sink. Regarding claim 9, wherein the hydrogen recombiner assembly is self-regulating and gravity-independent (at least in the passive heat sink which uses capillary force). Regarding claim 10, the limitation of the hydrogen recombiner assembly is positioned inside a spacecraft is considered an intended use limitation. A recitation with respect to the manner in which a claimed apparatus is intended to be employed does not differentiate the claimed apparatus from a prior art apparatus satisfying the structural limitations of the claims, as is the case here. Regarding claim 11, Broeckerhoff discloses a method for operating a hydrogen recombiner comprising: integrating a hydrogen recombiner (fig 1) with a passive heat sink (7), the passive heat sink comprising a heat transfer working fluid (¶0020), and the hydrogen recombiner comprising a catalyst (8, ¶0021); and utilizing the hydrogen recombiner to convert leaked hydrogen to water vapor (¶0002-0003). Regarding claim 12, Broeckerhoff further discloses wherein the hydrogen recombiner is a flameless hydrogen recombiner (as evident in fig 1). Regarding claim 13, Broeckerhoff further discloses wherein the catalyst comprises a platinum catalyst (¶0005). Regarding claim 14, Broeckerhoff further discloses wherein the passive heat sink (7) comprises an evacuated metallic cylindrical tube (as evident in fig 3) that is sealed and filled with the heat transfer working fluid (¶0020), with the heat transfer working fluid configured to flow in an annular space of the passive heat sink. Regarding claim 19, wherein the hydrogen recombiner assembly is self-regulating and gravity-independent (at least in the passive heat sink which uses capillary force). Regarding claim 20, the limitation of the hydrogen recombiner assembly is positioned inside a spacecraft is considered an intended use limitation. A recitation with respect to the manner in which a claimed apparatus is intended to be employed does not differentiate the claimed apparatus from a prior art apparatus satisfying the structural limitations of the claims, as is the case here. 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(s) 5-8 and 15-18 is/are rejected under 35 U.S.C. 103 as being unpatentable over Broeckerhoff as applied to claims 1 and 11 above, and further in view of Lo et al. (U.S. Patent Publication No. 2017/0153067, “Lo”). Regarding claims 5-8, Broeckerhoff discloses all previous claim limitations. However, Broeckerhoff does not explicitly disclose wherein the heat transfer working fluid is water, ammonia or methanol, wherein the passive heat sink comprises aluminum or stainless steel, wherein the passive heat sink comprises a metal tube, and wherein an inner wall of the passive heat sink includes a capillary porous wick lining, the capillary porous wick lining configured to enable transport of heat along a length of the passive heat sink. Lo, however, discloses a heat pipe (fig 6) wherein the heat transfer working fluid is water (¶0041),wherein the passive heat sink comprises aluminum (¶0041), wherein the passive heat sink comprises a metal tube (¶0041), and wherein an inner wall of the passive heat sink includes a capillary porous wick lining (100, ¶0041), the capillary porous wick lining configured to enable transport of heat along a length of the passive heat sink (¶0041). Lo teaches that these configurations improve heat transfer capacity of the heat pipe (¶0043). It would have been obvious to a person of ordinary skill in the art before the effective filing date of the claimed invention for Broeckerhoff to provide the heat pipe configuration of Lo for the passive heat sink in order to improve heat exchange capacity. Regarding claims 15-18, Broeckerhoff discloses all previous claim limitations. However, Broeckerhoff does not explicitly disclose wherein the heat transfer working fluid is water, ammonia or methanol, wherein the passive heat sink comprises aluminum or stainless steel, wherein the passive heat sink comprises a metal tube, and wherein an inner wall of the passive heat sink includes a capillary porous wick lining, the capillary porous wick lining configured to enable transport of heat along a length of the passive heat sink. Lo, however, discloses a heat pipe (fig 6) wherein the heat transfer working fluid is water (¶0041),wherein the passive heat sink comprises aluminum (¶0041), wherein the passive heat sink comprises a metal tube (¶0041), and wherein an inner wall of the passive heat sink includes a capillary porous wick lining (100, ¶0041), the capillary porous wick lining configured to enable transport of heat along a length of the passive heat sink (¶0041). Lo teaches that these configurations improve heat transfer capacity of the heat pipe (¶0043). It would have been obvious to a person of ordinary skill in the art before the effective filing date of the claimed invention for Broeckerhoff to provide the heat pipe configuration of Lo for the passive heat sink in order to improve heat exchange capacity. Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to HARRY E ARANT whose telephone number is (571)272-1105. The examiner can normally be reached Monday-Friday 10-6 ET. 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, Jianying Atkisson can be reached at (571)270-7740. 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. /HARRY E ARANT/Primary Examiner, Art Unit 3763
Read full office action

Prosecution Timeline

Jun 13, 2023
Application Filed
Jan 03, 2026
Non-Final Rejection — §102, §103 (current)

Precedent Cases

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

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Prosecution Projections

1-2
Expected OA Rounds
48%
Grant Probability
71%
With Interview (+22.4%)
3y 9m
Median Time to Grant
Low
PTA Risk
Based on 569 resolved cases by this examiner. Grant probability derived from career allow rate.

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