Prosecution Insights
Last updated: April 19, 2026
Application No. 18/228,815

CONDENSER TUBE WITH NON-UNIFORM SURFACE ENHANCEMENTS

Final Rejection §103
Filed
Aug 01, 2023
Examiner
TAVAKOLDAVANI, KAMRAN
Art Unit
3763
Tech Center
3700 — Mechanical Engineering & Manufacturing
Assignee
Liquidstack Holding B V
OA Round
2 (Final)
83%
Grant Probability
Favorable
3-4
OA Rounds
2y 6m
To Grant
90%
With Interview

Examiner Intelligence

Grants 83% — above average
83%
Career Allow Rate
351 granted / 424 resolved
+12.8% vs TC avg
Moderate +7% lift
Without
With
+6.8%
Interview Lift
resolved cases with interview
Typical timeline
2y 6m
Avg Prosecution
57 currently pending
Career history
481
Total Applications
across all art units

Statute-Specific Performance

§101
0.2%
-39.8% vs TC avg
§103
46.4%
+6.4% vs TC avg
§102
24.8%
-15.2% vs TC avg
§112
28.0%
-12.0% vs TC avg
Black line = Tech Center average estimate • Based on career data from 424 resolved cases

Office Action

§103
DETAILED ACTION Claims filed on 9/30/2025 have been entered. Claims 11, 12, 16-19 are cancelled. 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 In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status. 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 set forth in Graham v. John Deere Co., 383 U.S. 1, 148 USPQ 459 (1966), that are applied 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 1-10, 13-15, 20 are rejected under 35 U.S.C. 103 as being unpatentable over Sathyamurthi (US 2019/0162455 A1), in view of An (CN 112033208 A). Claim 1: Sathyamurthi discloses a condenser tube (i.e., FIG.1) comprising: a tube (i.e., 110) having a first end (i.e., inherent), a second end (i.e., inherent) opposite the first end, an interior surface (i.e., inherent), and an exterior surface (i.e., inherent; to clarify, the tube has interior surface which refrigerant flows and includes exterior surface and both ends); a longitudinal bore (i.e., inherent) defined by the interior surface (i.e., inherent) and extending from the first end to the second end (i.e., inherent) and configured to transport a coolant (i.e., paragraph [23]: refrigerant used as coolant); Sathyamurthi discloses the claimed limitations in claim 1, but fails to disclose a cylindrical tube having an exterior surface; wherein the exterior surface comprises: a top semi-cylindrical surface located above a horizontal midplane of the cylindrical tube; and a bottom semi-cylindrical surface located below the horizontal midplane of the cylindrical tube, and wherein the top semi-cylindrical surface comprises a substantially smooth region free of surface enhancements, and the bottom semi-cylindrical surface comprises a plurality of self-draining surface enhancements extending longitudinally from the first end to the second end, wherein the plurality of self-draining surface enhancements are configured to shed a condensate due to gravity. However, An teaches a cylindrical tube (i.e., pipe 1 is cylindrical shape having a diameter) having an exterior surface (i.e., inherent; to clarify, the tube has interior surface which refrigerant flows and includes exterior surface and both ends); the exterior surface (i.e., exterior surface of pipe 1) comprises: a top semi-cylindrical surface (i.e., annotated FIG.4; pipe 1 is cylindrical shape having a diameter) located above a horizontal midplane (i.e., annotated FIG.4) of the cylindrical tube (i.e., pipe1); and a bottom semi-cylindrical surface (i.e., bottom portion where fin root 41 extends) located below the horizontal midplane (i.e., annotated FIG.4) of the cylindrical tube (i.e., pipe1), and wherein the top semi-cylindrical surface (i.e., annotated FIG.4) comprises a substantially smooth region free of surface enhancements (i.e., fins 4 are enhancements; there are no fins on top surface), and the bottom semi-cylindrical surface (i.e., bottom portion where fin root 41 extends; to clarify, outer surface of pipe has fins 4) comprises a plurality of surface self-draining enhancements (i.e., paragraph [21]: guide groove gathers condensed liquid and drain it downward ensure sharp part of fin always in thin liquid film; to clarify outer surface interpreted to have top portion and bottom portion, further inner surface of pipe has spiral inner tooth) extending longitudinally from the first end to the second end (i.e., see annotated FIG.4), wherein the plurality of self-draining surface enhancements (i.e., 4) are configured to shed a condensate due to gravity (i.e., to clarify, natural force gravity enhances the drain of condensed liquid downward from surface of fin) for the purpose of improving the heat transfer efficiency of the tubes (paragraph [5]). Therefore, it would have been obvious to one of ordinary skill in the art before the effective filling date of the claimed invention was made to modify the invention of Sathyamurthi to include a cylindrical tube having an exterior surface; the exterior surface comprises: a top semi-cylindrical surface located above a horizontal midplane of the cylindrical tube; and a bottom semi-cylindrical surface located below the horizontal midplane of the cylindrical tube, and wherein the top semi-cylindrical surface comprises a substantially smooth region free of surface enhancements, and the bottom semi-cylindrical surface comprises a plurality of self-draining surface enhancements extending longitudinally from the first end to the second end, wherein the plurality of self-draining surface enhancements are configured to shed a condensate due to gravitas taught by An in order to improve the heat transfer efficiency of the tubes. PNG media_image1.png 374 586 media_image1.png Greyscale Claim 2: Sathyamurthi as modified discloses the apparatus as claimed in claim 1, wherein the plurality of self-draining surface enhancements (An i.e., 4) extend radially from the bottom semi-cylindrical surface (An i.e., annotated FIG.4). Claim 3: Sathyamurthi as modified discloses the apparatus as claimed in claim 2, wherein the plurality of self-draining surface enhancements comprise a plurality of fins (An i.e., 4). Claim 4: Sathyamurthi as modified discloses the apparatus as claimed in claim 2, wherein the plurality of self-draining surface enhancements (An i.e., 4) each extend either horizontally (An i.e., see FIG.4) or downward from the exterior surface. Claim 5: Sathyamurthi as modified discloses the apparatus as claimed in claim 2, wherein the plurality of self-draining surface enhancements (An i.e., 4) each extend downward from the exterior surface (An i.e., see figure below; to clarify, figure 4 is a cross section of pipe, pipe is circular shape therefore top and bottom are relative to the position of the pipe). PNG media_image2.png 292 509 media_image2.png Greyscale Claim 6: Sathyamurthi as modified discloses the apparatus as claimed in claim 1, wherein the plurality of self-draining surface enhancements (An i.e., 4) each extend horizontally from the exterior surface (An i.e., see FIG.4). Claim 7: Sathyamurthi as modified discloses the apparatus as claimed in claim 2, wherein the plurality of self-draining surface enhancements comprise a plurality of fins (An i.e., fins 4 used as enhancements) extending from the first end to the second end (Sathyamurthi i.e., inherent). Claim 8: Sathyamurthi as modified discloses the apparatus as claimed in claim 5, wherein the plurality of self-draining surface enhancements (An i.e., 4) extend in a parallel configuration (An i.e., see FIG.4) and where a first surface enhancement (An i.e., surface is inherent) is recessed relative to a second surface enhancement (An i.e., surface is inherent) that is above and adjacent to the first surface enhancement (An i.e., see FIG.4). Claim 9: Sathyamurthi as modified discloses the apparatus as claimed in claim 1, wherein the condenser tube is part of a condenser (i.e., 401). Claim 10: Sathyamurthi as modified discloses the apparatus as claimed in claim 9, wherein the condenser is part of a two-phase immersion cooling system (i.e., paragraph [31]: HVAC system using condenser for cooling process using refrigerant in liquid/gas phase). Claim 13: Sathyamurthi as modified discloses the apparatus as claimed in claim 1, wherein the plurality of self-draining surface enhancements comprise a plurality of pointed fins (An i.e., fins 4) that taper in a direction from a base (An i.e., inherent) to a tip (An i.e., inherent) of each fin (An i.e., see FIG.4). Claim 14: Sathyamurthi as modified discloses the apparatus as claimed in claim 1, wherein the interior surface is substantially smooth (i.e., based on broadest reasonable interpretation, inner surface is substantially smooth). Claim 15: Sathyamurthi as modified discloses the apparatus as claimed in claim 3, wherein each fin has a maximum fin length greater than a minimum distance between adjacent fins (An i.e., it would have been obvious to one of ordinary skill in the art before the effective filling date of the claimed invention was made to further modify the apparatus of An to include each fin has a maximum fin length greater than a minimum distance between adjacent fins in order to enhance the heat transfer efficiency of the pipe, since it has been held that discovering an optimum value of a result effective variable involves only routine skill in the art - Optimum value: MPEP 2144.05 II-B). PNG media_image2.png 292 509 media_image2.png Greyscale Claim 20: Sathyamurthi discloses a condenser for a two-phase immersion cooling system (i.e., preamble/intended use), the condenser (i.e., FIG.1) comprising: an inlet manifold (i.e., 140) comprising an inlet (i.e., 191); an outlet manifold (i.e., 141) comprising an outlet (i.e., 192); a plurality of condenser tubes (i.e., 110) fluidly connecting the inlet manifold (i.e., 140) to the outlet manifold (i.e., 141); wherein at least one of the plurality of condenser tubes (i.e., 110) comprises: a tube having a first end (i.e., inherent), a second end (i.e., inherent) opposite the first end, an interior surface (i.e., inherent), and an exterior surface (i.e., inherent; to clarify, the tube has interior surface which refrigerant flows and includes exterior surface and both ends); a longitudinal bore (i.e., inherent) defined by the interior surface (i.e., inherent) and extending from the first end to the second end (i.e., inherent) and configured to transport a heat transfer fluid (i.e., paragraph [23]: refrigerant used as heat transfer fluid); wherein the interior surface is substantially smooth (i.e., based on broadest reasonable interpretation, inner surface is substantially smooth); Sathyamurthi discloses the claimed limitations in claim 20, but fails to disclose a cylindrical tube having an exterior surface; wherein the exterior surface comprises: a top semi-cylindrical surface located above a horizontal midplane of the cylindrical tube; and a bottom semi-cylindrical surface located below the horizontal midplane of the cylindrical tube, and wherein the top semi-cylindrical surface comprises a substantially smooth region free of surface enhancements, and the bottom semi-cylindrical surface comprises a plurality of self-draining surface enhancements extending longitudinally from the first end to the second end, wherein the plurality of self-draining surface enhancements are configured to shed a condensate due to gravity. However, An teaches a cylindrical tube (i.e., pipe 1 is cylindrical shape having a diameter) having an exterior surface (i.e., inherent; to clarify, the tube has interior surface which refrigerant flows and includes exterior surface and both ends); the exterior surface (i.e., exterior surface of pipe 1) comprises: a top semi-cylindrical surface (i.e., annotated FIG.4; pipe 1) located above a horizontal midplane (i.e., annotated FIG.4) of the cylindrical tube (i.e., pipe1); and a bottom semi-cylindrical surface (i.e., bottom portion where fin root 41 extends) located below the horizontal midplane (i.e., annotated FIG.4) of the cylindrical tube (i.e., pipe1), and wherein the top semi-cylindrical surface (i.e., annotated FIG.4) comprises a substantially smooth region free of surface enhancements (i.e., fins 4 are enhancements; there are no fins on top surface), and the bottom semi-cylindrical surface (i.e., bottom portion where fin root 41 extends; to clarify, outer surface of pipe has fins 4) comprises a plurality of surface self-draining enhancements (i.e., paragraph [21]: guide groove gathers condensed liquid and drain it downward ensure sharp part of fin always in thin liquid film; to clarify outer surface interpreted to have top portion and bottom portion, further inner surface of pipe has spiral inner tooth) extending longitudinally from the first end to the second end (i.e., see annotated FIG.4), wherein the plurality of self-draining surface enhancements (i.e., 4) are configured to shed a condensate due to gravity (i.e., to clarify, natural force gravity enhances the drain of condensed liquid downward from surface of fin) for the purpose of improving the heat transfer efficiency of the tubes (paragraph [5]). Therefore, it would have been obvious to one of ordinary skill in the art before the effective filling date of the claimed invention was made to modify the invention of Sathyamurthi to include a cylindrical tube having an exterior surface; the exterior surface comprises: a top semi-cylindrical surface located above a horizontal midplane of the cylindrical tube; and a bottom semi-cylindrical surface located below the horizontal midplane of the cylindrical tube, and wherein the top semi-cylindrical surface comprises a substantially smooth region free of surface enhancements, and the bottom semi-cylindrical surface comprises a plurality of self-draining surface enhancements extending longitudinally from the first end to the second end, wherein the plurality of self-draining surface enhancements are configured to shed a condensate due to gravitas taught by An in order to improve the heat transfer efficiency of the tubes. PNG media_image1.png 374 586 media_image1.png Greyscale Response to Arguments Applicant's arguments filed on 9/30/2025, with respect to all the claims under Claim Rejections - 35 USC § 103 have been fully considered and they are moot. Applicant’s arguments to new features and amendments are addressed in this office action. Therefore, a new ground(s) of rejections have been made in response to the amendments. 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 KAMRAN TAVAKOLDAVANI whose telephone number is (313)446-6612. The examiner can normally be reached M-F 8:00 am to 5:00 pm EST. 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. /KAMRAN TAVAKOLDAVANI/Examiner, Art Unit 3763 /LEN TRAN/Supervisory Patent Examiner, Art Unit 3763
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Prosecution Timeline

Aug 01, 2023
Application Filed
Mar 24, 2025
Non-Final Rejection — §103
Sep 30, 2025
Response Filed
Oct 31, 2025
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
83%
Grant Probability
90%
With Interview (+6.8%)
2y 6m
Median Time to Grant
Moderate
PTA Risk
Based on 424 resolved cases by this examiner. Grant probability derived from career allow rate.

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