Prosecution Insights
Last updated: April 19, 2026
Application No. 18/575,731

HEAT EXCHANGER AND MANUFACTURING METHOD THEREFOR

Non-Final OA §102§103§112
Filed
Dec 29, 2023
Examiner
ARANT, HARRY E
Art Unit
3763
Tech Center
3700 — Mechanical Engineering & Manufacturing
Assignee
Zhejiang Ascenrise Heat Pump Co. Ltd.
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 §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 . Election/Restrictions Claims 13-15 are withdrawn from further consideration pursuant to 37 CFR 1.142(b), as being drawn to a nonelected Invention, there being no allowable generic or linking claim. Applicant timely traversed the restriction (election) requirement in the reply filed on 11/28/2025. Applicant's election with traverse of the restriction in the reply filed on 11/28/2025 is acknowledged. The traversal is on the ground(s) that there is no undue burden to the examiner. This is not found persuasive because being a nation stage application there is a requirement for unity of invention if no restriction were to be required, the claims lack unity as laid out in the restriction requirement. The requirement is still deemed proper and is therefore made FINAL. 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. Claims 1-12 are 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. Claim 1 recites “wherein the fluid channel sheet” in line 2, which is unclear to which fluid channel sheet the claim is referring. For examining purposes the limitation will interpreted as --wherein a fluid channel sheet--. Claim 3 recites “the O-XY plane” in line 2, which lacks proper antecedent basis. For examining purposes the limitation will be interpreted --the O-XY direction--. Claim 4 recites “the O-XY plane” in line 2, which lacks proper antecedent basis. For examining purposes the limitation will be interpreted --the O-XY direction--. Claims 2-12 are rejected to on the basis of their dependency on claim 1. 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) 1-12 is/are rejected under 35 U.S.C. 103 as being unpatentable over Fischer (PCT Publication WO88/01722) in view of Han et al. (Chinese Patent Publication CN106370043A, “Han”). Regarding claim 1, Fischer discloses a heat exchanger (fig 8a,8b embodiment), comprising a plurality of working fluid channel sheets stacked along an O-Z direction (stacking direction), wherein a working fluid channel sheet comprise an inlet (see annotated fig 8b below), an outlet (see annotated fig 8b below) and a heat exchange region (see annotated fig 8b below) located between the inlet and the outlet; the heat exchange region is provided with a plurality of structures (12a-d, 16, 17, 18); center points of the microstructures on the adjacent working fluid channel sheets (fig 8a and fig 8b) are aligned along an O-XY direction (see annotated fig 8b below); and the structures on the adjacent working fluid channel sheets (fig 8a) have different shapes. However, Fischer does not explicitly disclose microstructures. Han, however, discloses a heat exchanger wherein a heat exchange region is provided with a plurality of microstructures (3, fig 1). Fischer teaches that microstructure heat exchangers provide small size and light weight (page 1, lines 19-25). It would have been obvious for Han to have the structures be microstructures in order to reduce the size and weight of the heat exchanger. The limitations of the microstructures being formed by stamping is considered a product-by-process limitation. In product-by-process claims, “once a product appearing to be substantially identical is found and a 35 U.S.C. 102/103 rejection [is] made, the burden shifts to the applicant to show an unobvious difference.” MPEP 2113. This rejection under 35 U.S.C. 102/103 is proper because the “patentability of a product does not depend on its method of production.” In re Thorpe, 227 USPQ 964, 966 (Fed. Cir. 1985). PNG media_image1.png 443 783 media_image1.png Greyscale Regarding claim 2, the combination of Fischer and Han discloses all previous claim limitations. Fischer, as modified, further discloses wherein the working fluid channel sheets (fig 8a and fig 8b) comprise a plurality of first working fluid channel sheets (fig 8b) and a plurality of second working fluid channel sheets (fig 8a) alternately stacked, and the microstructures (12a-d, 16, 17, 18, of Fischer, see rejection of claim 1 wherein Li teaches microstructures) comprise first microstructures (12a-d) disposed on the first working fluid channel sheets and second microstructures (16, 17, 18) disposed on the second working fluid channel sheets; and in the O-XY direction (see annotated fig 8b below), a part of a first edge portion (see annotated fig 8b) of the first microstructure exceeds the second microstructure. PNG media_image2.png 443 783 media_image2.png Greyscale Regarding claim 3, the combination of Fischer and Han discloses all previous claim limitations. Fischer further discloses wherein projections (of 12a-d, 16, 17, 18) of the first edge portion and a second edge portion in the O-XY direction (see annotated fig 2 below) along the O-Z direction (stacking direction) do not overlap. PNG media_image3.png 443 783 media_image3.png Greyscale Regarding claim 4, the combination of Fischer and Han discloses all previous claim limitations. Fischer, as modified, further discloses wherein taking a projection of the center point of the first microstructure (12a-d, see rejection of claim 1 wherein Li teaches microstructures m) in the O-XY direction (see annotated fig 8b below) along the O-Z direction (stacking direction) as a center of circle (see annotated fig 8b below), the projections (of 12a-d, 16, 17, 18) of the first edge portion (see annotated fig 8b below) and the second edge portion (see annotated fig 8b below) are disposed at intervals along a circumferential direction of the center of circle. PNG media_image4.png 443 783 media_image4.png Greyscale Regarding claim 5, the combination of Fischer and Han discloses all previous claim limitations. Fischer, as modified, further discloses wherein the first microstructure (12a-d) comprises at least one first edge portion (see annotated fig 8b below) exceeding the second microstructure along an O-Y direction (see annotated fig 8b below), and the second microstructure (16, 17, 18) comprises at least one second edge portion exceeding the first microstructure along an O-X direction (see annotated fig 8b below). PNG media_image5.png 443 783 media_image5.png Greyscale Regarding claim 6, the combination of Fischer and Han discloses all previous claim limitations. Fischer, as modified, further discloses wherein the first microstructure (12a-d) is gourd-shaped (see annotated fig 8b below), and the second microstructure (16, 17, 18) circular (see annotated fig 1 below). PNG media_image6.png 443 783 media_image6.png Greyscale PNG media_image7.png 271 420 media_image7.png Greyscale Regarding claim 7, the combination of Fischer and Han discloses all previous claim limitations. Fischer, as modified, further discloses wherein both ends (see annotated fig 8b below) of the first microstructure (12a-d) along the O-Y direction (see annotated fig 8b below) exceed the second microstructure (16, 17, 18), and both ends (see annotated fig 8b below) of the second microstructure along the O-X direction (see annotated fig 8b below) exceed the first microstructure. PNG media_image8.png 443 783 media_image8.png Greyscale Regarding claim 8, the combination of Fischer and Han discloses all previous claim limitations. Fischer, as modified, further discloses heat exchange region comprises a turbulent region (see annotated fig 8b below) and transition regions (see annotated fig 8b below) located on two sides of the turbulent region along a direction from a side where the inlet is located to a side where the outlet is located, a density of the microstructures (12a-d) disposed in the turbulent region is greater than a density of the microstructures disposed in the transition region; the plurality of microstructures are arranged at intervals along a plurality of sine curves (see annotated fig 8b below), and the plurality of sine curves are arranged at intervals from the side where the inlet (see annotated fig 8b below) is located to the side where the outlet (see annotated fig 8b below) is located; and a number of the sine curves located in the turbulent region is not greater than 3 (as there is only 1). PNG media_image9.png 443 783 media_image9.png Greyscale Regarding claim 9, the combination of Fischer and Han discloses all previous claim limitations. Fischer, as modified, further discloses wherein a pitch (see annotated fig 8b below) between every two adjacent sine curves in the transition region is greater than a pitch between every two adjacent sine curves in the turbulent region (see annotated fig 8b below). PNG media_image10.png 443 783 media_image10.png Greyscale Regarding claim 10, the combination of Fischer and Han discloses all previous claim limitations. Fischer, as modified, further discloses wherein the working fluid channel sheets comprise a plurality of first working fluid channel sheets (1) and a plurality of second working fluid channel sheets (2) stacked alternately along the O-Z direction (stacking direction); the first working fluid channel sheets each comprise a first inlet (see annotated fig 8a below), a first outlet and a first heat exchange region located between the first inlet and the first outlet, the first heat exchange region is provided with a plurality of first microstructures (12a-d); and the second working fluid channel sheets each comprise a second inlet (see annotated fig 8a below), a second outlet (see annotated fig 8a below) and a second heat exchange region (see annotated fig 8a below) located between the second inlet and the second outlet, the second heat exchange region is provided with a plurality of second microstructures; and wherein a side of the first microstructure facing the first inlet and a side of the second microstructure facing the second inlet have different shapes (see annotated fig 8a below). PNG media_image11.png 335 738 media_image11.png Greyscale Regarding claim 11, the combination of Fischer and Han discloses all previous claim limitations. Fischer, as modified, further discloses wherein the side of the first microstructure (12a-d) facing the first inlet is arc-shaped (see fig 1), and the side of the second microstructure (16, 17, 18) facing the second inlet is pointed (see annotated fig 8a above). Regarding claim 12, the combination of Fischer and Han discloses all previous claim limitations. Fischer, as modified, further discloses wherein the heat exchanger further comprises a first inflow chamber (formed by the first inlets, see annotated fig 8a above) communicating with a plurality of first inlets, and the heat exchanger further comprises a second inflow chamber (formed by the second inlets, see annotated fig 8a above) communicating with a plurality of second inlets. However, Fischer does not explicitly disclose and a first inflow tube or a first inflow tube joint communicating with the first inflow chamber, an extending direction of the first inflow tube or the first inflow tube joint intersects with an arrangement direction of the first inlets and the first heat exchange regions; and a second inflow tube or a second inflow tube joint communicating with the second inflow chamber, an extending direction of the second inflow tube or the second inflow tube is the same as an arrangement direction of the second inlets and the second heat exchange regions. However, the examiner takes Official Notice that inflow tubes are old and well known in the art of heat exchangers and it would have been obvious to a person of ordinary skill in the art before the effective filing date of the claimed invention for Fischer to provide inflows pipes in order to allow for circulation of the fluids. 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

Dec 29, 2023
Application Filed
Jan 10, 2026
Non-Final Rejection — §102, §103, §112 (current)

Precedent Cases

Applications granted by this same examiner with similar technology

Patent 12601547
EXTRUDED CONNECTED MICROTUBE AND HEAT EXCHANGER
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Patent 12578144
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2y 5m to grant Granted Mar 17, 2026
Patent 12546545
ALUMINUM ALLOY HEAT EXCHANGER
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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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