Prosecution Insights
Last updated: April 19, 2026
Application No. 18/196,662

MODULAR HEAT EXCHANGER FOR AN AIRCRAFT POWERPLANT

Non-Final OA §102§103
Filed
May 12, 2023
Examiner
RUPPERT, ERIC S
Art Unit
3763
Tech Center
3700 — Mechanical Engineering & Manufacturing
Assignee
Raytheon Technologies Corporation
OA Round
1 (Non-Final)
59%
Grant Probability
Moderate
1-2
OA Rounds
2y 10m
To Grant
83%
With Interview

Examiner Intelligence

Grants 59% of resolved cases
59%
Career Allow Rate
437 granted / 739 resolved
-10.9% vs TC avg
Strong +24% interview lift
Without
With
+24.1%
Interview Lift
resolved cases with interview
Typical timeline
2y 10m
Avg Prosecution
55 currently pending
Career history
794
Total Applications
across all art units

Statute-Specific Performance

§101
0.4%
-39.6% vs TC avg
§103
48.5%
+8.5% vs TC avg
§102
21.1%
-18.9% vs TC avg
§112
27.3%
-12.7% vs TC avg
Black line = Tech Center average estimate • Based on career data from 739 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 . Election/Restrictions Claims 4, 11-12 are withdrawn from further consideration pursuant to 37 CFR 1.142(b) as being drawn to a nonelected invention, there being no allowable generic or linking claim. Election was made without traverse in the reply filed on 11/18/2025. Applicant’s election without traverse of Species A, i in the reply filed on 11/18/2025 is acknowledged. 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) 1-3, 5, 7-10, 13-16, 20 is/are rejected under 35 U.S.C. 102 (a) (1) as being anticipated by Berg (US2729433A). Regarding claim 1, Berg discloses an apparatus (see Fig. 1-6) for an aircraft powerplant (this is a statement of intended use), comprising: a heat exchanger including a frame (adjacent frames 15), a plurality of heat exchanger cores (cores sections 16), a first flowpath (interior of core sections) and a second flowpath (exterior of core sections); the frame extending circumferentially about an axis (see central axis thereof), and the frame comprising a plurality of receptacles (interiors of frames 15) within an interior of the frame; each of the plurality of heat exchanger cores (core sections 16) housed within a respective one of the plurality of receptacles; the first flowpath extending in a first direction across the heat exchanger and through the plurality of heat exchanger cores; and the second flowpath extending in a second direction across the heat exchanger and through the plurality of heat exchanger cores. Regarding claim 2, Berg discloses the limitations of claim 2, and Berg further discloses a first of the plurality of heat exchanger cores (16) is configured to move (each core section being removably secured – Col. 4, lines 15-25), while housed within a first of the plurality of receptacles, at least one of axially relative to the frame; radially relative to the frame; or laterally relative to the frame. Regarding claim 3, Berg discloses the limitations of claim 1, and Berg further discloses a first of the plurality of heat exchanger cores is moveably secured to the frame while housed within a first of the plurality of receptacles (each core section being removably secured – Col. 4, lines 15-25). Regarding claim 5, Berg discloses the limitations of claim 1, and Berg further discloses the frame (15) forms an exoskeleton around the plurality of heat exchanger cores (16). Regarding claim 7, Berg discloses the limitations of claim 1, and Berg further discloses the frame (15) includes a plurality of elongated members arranged to form edges of a hexahedral unit (see hexahedral shape of Fig. 4); and a first of the plurality of receptacles is formed by and within the hexahedral unit. Regarding claim 8, Berg discloses the limitations of claim 1, and Berg further discloses the frame (see hoop formed by adjacent frames 15) is configured as a full-hoop body around the axis. Regarding claim 9, Berg discloses the limitations of claim 1, and Berg further discloses the frame is configured as an arcuate body extending partially about the axis (see arc formed by adjacent frames 15). Regarding claim 10, Berg discloses the limitations of claim 1, and Berg further discloses a first of the plurality of heat exchanger cores is circumferentially next to a second of the plurality of heat exchanger cores (adjacent frames 15). Regarding claim 13, Berg discloses the limitations of claim 1, and Berg further discloses the plurality of heat exchanger cores comprises a first heat exchanger core; the heat exchanger further includes a first seal element (29) disposed at a first side of the first heat exchanger core; and the first seal element seals a first gap between the frame and the first heat exchanger core. Regarding claim 14, Berg discloses the limitations of claim 13, and Berg further discloses the first seal element (29) is compressed between the frame and the first heat exchanger core. Regarding claim 15, Berg discloses the limitations of claim 13, and Berg further discloses the heat exchanger further includes a second seal element (second one of 29) disposed at a second side of the first heat exchanger core that is opposite the first side of the first heat exchanger core; and the second seal element seals a second gap between the frame and the first heat exchanger core. Regarding claim 16, Berg discloses the limitations of claim 1, and Berg further discloses the first direction is an axial direction; and the second direction is a radial direction (see flows of core sections 16). Regarding claim 20, Berg discloses an apparatus (see Fig. 1-6) for an aircraft propulsion system, comprising: a heat exchanger including a frame (frame 15), a first heat exchanger core (core section 16), a second heat exchanger core (second one of core section 16) a first flowpath (path interior of 16) and a second flowpath (path exterior of 16); the frame (15) extending circumferentially about an axis; the first heat exchanger core (16) housed within and movably retained within the frame; the second heat exchanger core housed within and movably retained within the frame (each core section being removably secured – Col. 4, lines 15-25), and the second heat exchanger core next to and disengaged from the first heat exchanger core (each core section being removably secured – Col. 4, lines 15-25); the first flowpath extending across the first heat exchanger core and the second heat exchanger core; and the second flowpath extending across the first heat exchanger core and the second heat exchanger core. 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) 6 and 18-19 is/are rejected under 35 U.S.C. 103 as being unpatentable over Berg (US2729433A) in view of Bond (US20150101334A1). Regarding claim 6, Berg teaches the limitations of claim 1, and Berg does not teach frame is configured as a lattice framework. Bond teaches the frame is configured as a lattice framework (see frame 84 with X-shaped bracing members 104; Fig. 6). Therefore, it would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to have modified Berg to include the lattice framework configuration of Bond, in order to improve strength of the frame (¶[0218]). Regarding claim 18, Berg teaches an apparatus of an aircraft powerplant (Fig. 1-6), comprising: a heat exchanger including a frame (15), a first heat exchanger core (16), a second heat exchanger core (another of 16), a first flowpath and a second flowpath (flowpaths through 16); the frame (15) including a plurality members arranged to form a first hexahedral unit and a second hexahedral unit the first hexahedral unit next to the second hexahedral unit (see shapes thereof), the first heat exchanger core arranged within the first hexahedral unit; the second heat exchanger core arranged within the second hexahedral unit; the first flowpath extending across the first heat exchanger core and the second heat exchanger core; and the second flowpath extending across the first heat exchanger core and the second heat exchanger core. Berg does not teach the frame including a plurality of lattice members arranged to form a first hexahedral unit and a second hexahedral unit, and the first hexahedral unit sharing one or more of the plurality of lattice members with the second hexahedral unit. Bond teaches a plurality of lattice members arranged to form a first hexahedral unit and a second hexahedral unit, and the first hexahedral unit sharing one or more of the plurality of lattice members with the second hexahedral unit (see frame 84 with X-shaped bracing members 104; Fig. 6). Therefore, it would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to have modified Berg to include the lattice framework configuration of Bond, in order to improve strength of the frame (¶[0218]). Regarding claim 19, Berg as modified teaches the limitations of claim 18, and Berg as modified further teaches the plurality of lattice members are arranged to further form a third hexahedral unit; the first hexahedral unit is between the second hexahedral unit and the third hexahedral unit, and the first hexahedral unit shares one or more of the plurality of lattice members with the third hexahedral unit (as modified above); the heat exchanger (see additional ones of 16) further includes a third heat exchanger core arranged within the third hexahedral unit; the first flowpath further extends across the third heat exchanger core; and the second flowpath further extends across the third heat exchanger core. Claim(s) 17 is/are rejected under 35 U.S.C. 103 as being unpatentable over Berg (US2729433A) in view of Nicita (US3831374A). Regarding claim 17, Berg teaches the limitations of claim 1, and does not teach an engine comprising an engine flowpath; and the first flowpath fluidly coupled with or configured as part of the engine flowpath. Nicita teaches engine comprising an engine flowpath; and the first flowpath fluidly coupled with or configured as part of the engine flowpath (intake air/exhaust gas flow paths through heat exchanger 16; Fig. 1). Therefore, it would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to have modified Berg to include wherein the first flowpath is fluidly coupled with an engine, in order to improve the efficiency thereof (Col. 2, lines 45-50). Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to ERIC S RUPPERT whose telephone number is (571)272-9911. The examiner can normally be reached Monday - Friday 8 am - 4 pm. 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, Len Tran can be reached at 571-272-1184. 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. /ERIC S RUPPERT/Primary Examiner, Art Unit 3763
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Prosecution Timeline

May 12, 2023
Application Filed
Jan 08, 2026
Non-Final Rejection — §102, §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

1-2
Expected OA Rounds
59%
Grant Probability
83%
With Interview (+24.1%)
2y 10m
Median Time to Grant
Low
PTA Risk
Based on 739 resolved cases by this examiner. Grant probability derived from career allow rate.

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