Prosecution Insights
Last updated: April 19, 2026
Application No. 18/531,534

Arrangement of Helical Tubes for Efficient Packing and Apparatus Implementing the Same

Final Rejection §103
Filed
Dec 06, 2023
Examiner
LANE, DEVON
Art Unit
3763
Tech Center
3700 — Mechanical Engineering & Manufacturing
Assignee
Neal Technologies Inc.
OA Round
2 (Final)
55%
Grant Probability
Moderate
3-4
OA Rounds
3y 2m
To Grant
70%
With Interview

Examiner Intelligence

Grants 55% of resolved cases
55%
Career Allow Rate
422 granted / 765 resolved
-14.8% vs TC avg
Moderate +15% lift
Without
With
+14.8%
Interview Lift
resolved cases with interview
Typical timeline
3y 2m
Avg Prosecution
46 currently pending
Career history
811
Total Applications
across all art units

Statute-Specific Performance

§101
0.3%
-39.7% vs TC avg
§103
50.7%
+10.7% vs TC avg
§102
20.5%
-19.5% vs TC avg
§112
27.0%
-13.0% vs TC avg
Black line = Tech Center average estimate • Based on career data from 765 resolved cases

Office Action

§103
DETAILED ACTION 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) 1-13 is/are rejected under 35 U.S.C. 103 as being unpatentable over Neal (US 2017/0175684) in view of Mansson (US 4,589,481). Regarding claim 1, Neal teaches heat exchangers comprising: a plurality of bundles of helical tubes (Figs. 3-5) each comprising a plurality of helical tubes of the same hand twist as each of the other bundles (Fig. 3) and having a common helical axis (48, 58) and outside surface (34, 54) with peaks and valleys, wherein the helical axis of each bundle is parallel to and in a location radially offset from the axes of the other bundles (see Fig. 3). Neal teaches helical bundles with the same hand twist but abutting peaks (Fig. 3) or different hand twist that are nested (Fig. 4) but does not teach bundles with the same hand twist and nested peaks and valleys. Mansson teaches that it is old and well-known to arrange helically twisted elements with the same hand twist and abutting peaks (Figs. 3-7; corresponding to Fig. 3 of Neal), with different hand twist that are nested (Figs. 14-18; corresponding to Fig. 4 of Neal), or with same hand twist and nested peaks and valleys (Figs. 10-13). It would have been obvious to one of ordinary skill in the art to arrange the elements of Neal in any of the art recognized arrangements taught by Mansson based on the desired spacing or packing density between elements required by a given application as Mansson demonstrates that such arrangements are old and well-known. Regarding claim 11, Neal teaches a heat exchanger comprising: first, second, and third, tube bundles (Fig. 3) each comprising a set of three tubes adapted to allow a first fluid to flow therethrough (from 12 to 14 in Fig. 5), the tubes having inlets and outlets attached to inlet and outlet supports (16, 26)the tubes following a helical path along a common helical axis (see Fig. 3; 48 or 58), the helical path of each tube having the same twist direction, pitch, and radius with symmetric peaks and valleys along the bundle length; a shell surrounds the tube bundles (28), the shell having inlet (30) and outlet (32) ports for flowing a second fluid through the shell past the bundles along the bundle lengths (see Fig. 1); the helical axes of the first through third bundles are parallel to and radially offset from each other (see Figs. 3 and 5). Neal teaches helical bundles with the same hand twist but abutting peaks (Fig. 3) or different hand twist that are nested (Fig. 4) but does not teach bundles with the same hand twist and nested peaks and valleys. Mansson teaches that it is old and well-known to arrange helically twisted elements with the same hand twist and abutting peaks (Figs. 3-7; corresponding to Fig. 3 of Neal), with different hand twist that are nested (Figs. 14-18; corresponding to Fig. 4 of Neal), or with same hand twist and nested peaks and valleys (Figs. 10-13). It would have been obvious to one of ordinary skill in the art to arrange the elements of Neal in any of the art recognized arrangements taught by Mansson based on the desired spacing or packing density between elements required by a given application as Mansson demonstrates that such arrangements are old and well-known. Neal further teaches that the bundles has tubes with the same coil diameter, tube diameter, and pitch (see Fig. 3), per claim 2; each bundle has the same coil diameter, tube diameter and pitch (see Fig. 3), per claim 3; bundles have the same number of tubes per bundle (Fig. 3), per claim 4; and the number of tubes and groupings are known to vary between 2 and greater (see Para. [0034]), per claims 5-8. Regarding claims 9-10 and 12, each bundle has a coil diameter, tube diameter, and bundle center located at the axis (see Fig. 3 of Neal). Per the combination above, the distance from center to center of each bundle is less than the sum of the two diameters due to the nesting (see Figs. 11-13 of Mansson); and tubes of adjacent bundles touch tangent at points between the bundle peaks and valleys (see Fig. 12 of Mansson). Regarding claim 13, the number of additional identical tube bundles is a duplication of parts which, absent unexpected results, is within the ordinary skill. Response to Arguments Applicant's arguments filed 9/9/25 have been fully considered but they are not persuasive. Applicant’s arguments as to the differences between Neal and Mansson are not persuasive. The coiled tubes of Mansson, while formed from a single tube, face the exact same packaging challenges. Applications in the prior art commonly consider spirally wound individual tubes and spiral single tubes concurrently (evidence: US 2023/0110296; Figs. 3-5) and one of ordinary skill would have known to look to teachings such as Mansson for guidance. The examiner could not locate grounding for the discussion about “triangular” and “rectangular” spacing in the claim language. 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 Devon Lane whose telephone number is (571)270-1858. The examiner can normally be reached M-Th, 9-4. 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, Jerry-Daryl Fletcher can be reached at 571.270.5054. 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. /DEVON LANE/ Primary Examiner, Art Unit 3763
Read full office action

Prosecution Timeline

Dec 06, 2023
Application Filed
May 20, 2025
Response after Non-Final Action
Jun 06, 2025
Response after Non-Final Action
Aug 07, 2025
Non-Final Rejection — §103
Sep 09, 2025
Response Filed
Mar 09, 2026
Final Rejection — §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

3-4
Expected OA Rounds
55%
Grant Probability
70%
With Interview (+14.8%)
3y 2m
Median Time to Grant
Moderate
PTA Risk
Based on 765 resolved cases by this examiner. Grant probability derived from career allow rate.

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