Prosecution Insights
Last updated: August 16, 2026
Application No. 18/097,657

WOUND-PLEATED FILTERS AND RELATED METHODS

Final Rejection §102§103§Other
Filed
Jan 17, 2023
Priority
Jan 21, 2022 — provisional 63/301,929
Examiner
MENON, KRISHNAN S
Art Unit
1777
Tech Center
1700 — Chemical & Materials Engineering
Assignee
Entegris Inc.
OA Round
4 (Final)
60%
Grant Probability
Moderate
5-6
OA Rounds
0m
Est. Remaining
71%
With Interview

Examiner Intelligence

Grants 60% of resolved cases
60%
Career Allowance Rate
900 granted / 1505 resolved
-5.2% vs TC avg
Moderate +12% lift
Without
With
+11.5%
Interview Lift
resolved cases with interview
Typical timeline
3y 3m
Avg Prosecution
75 currently pending
Career history
1569
Total Applications
across all art units

Statute-Specific Performance

§101
2.0%
-38.0% vs TC avg
§103
40.6%
+0.6% vs TC avg
§102
23.8%
-16.2% vs TC avg
§112
24.0%
-16.0% vs TC avg
Black line = Tech Center average estimate • Based on career data from 1505 resolved cases

Office Action

§102 §103 §Other
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 § 102/103 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. 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, 3-7, 9, 16, 17, 20, 21 and 29 are rejected under 35 U.S.C. 102a1 as being anticipated by, or in the alternative, under 35 USC 103 as unpatentable over, Weyand (US 3,726,407.) At the outset, the newly added claim limitation of 7/14/26: “wherein each filter membrane layer of the multiple windings is alternately connected to two different adjacent filter membrane layers such that a first end of each filter membrane layer forms a wound pleat with a first end of a first adjacent filter membrane layer, and a second end of each filter membrane layer forms a wound pleat with a second end of a second, different adjacent filter membrane layer” only describes how the pleats in a pleated filter are constructed. This would not overcome any of the references cited in this office action and the rejections 1-4. Weyand teaches a spiral wound pleated filter as claimed. See the abstract, and the annotated figure 4 copied herein, which shows multiple layers of filter membrane wound with alternating spacer layers, such that the inlet surfaces of the adjacent membranes face each-other, and the outlet surfaces of adjacent membranes face each-other. Spacers 9 are on the inlet side and 10 are on the outlet side. The whole construction is rolled into a spiral structure around a core. Regarding capability of removing trace impurities from a fluid – the Weyand membrane is intended for filtering fluids. Trace only means very small amounts of impurities. PNG media_image1.png 558 1069 media_image1.png Greyscale The new amendment of 10/13/25, “each of the inlet surfaces of the filter membrane layers is open to the inlet end of the wound-pleated filter” in claims 1 and 20, and “each of the outlet surfaces of the filter membrane layers is open to the outlet end of the wound-pleated filter” in claims 3 and 21: Weyand teaches a 3-stage filter in series, meaning, filtrate from stage 1 is feed to stage 2, etc. As is clear from Fig. 4, these claim elements are met for each stage of the filter. Therefore, each stage in Weyand is a filter as recited in the instant claims. Please note that the claims do not preclude added filter stages. Regarding the element: PNG media_image2.png 127 733 media_image2.png Greyscale . Each stage of the Weyand filter meets this claim requirement. For example, the first stage of Weyand has the fluid entering the stage in the same axial direction though all layers of the first stage. What applicant is claiming is the first stage of the Weyand filter as separated to a stand-alone filter. Weyand also has explicit teaching for this in col. 1, lines 19-39, background of the invention, which teaches a single stage filter as applicant claims. Weyand’s invention is to overcome some of the drawbacks explained in the subsequent lines 39-55 about this single stage construction. (An example of the prior art Weyand describes is USP 3,962,097 to Reiman et al. See rejection 4.) Claims 4-7, 20 and 21: adhesive strips 18 and 26 bond the layers. Col. 3, lines 6-20. Adhesive is heat-sealable material like polyethylene – col. 5, lines 31. Claim 17: spacer thickness is 500-750 microns – col. 4 line 62. Claim 29: the filter of Weyand is used for filtering fluids to remove impurities. Trace only means impurities are in small quantities. Abstract. Claim(s) 10-14 and 22-23 are rejected under 35 U.S.C. 103 as being unpatentable over Weyand (US 3,726,407) in view of A Clarifying Guide to Membrane Filtration: EMD Millipore.com, 2017. Claims 12 –14: the filter membrane being symmetric or asymmetric – only two options, and applicant has claimed both. This would have been obvious. Inlet surface area: while Weyand is silent, the actual surface area required can be designed based on the application and capacity required. Weyand, while teaching filter media as being commercially available (see col. 5 lines 18-30,) is silent on the claimed materials as in claims 10 and 23 and thickness as in claims 11 and 22 for the filter membrane. However, these are commonly used materials for the purpose and not inventive unless otherwise shown. Millipore, a paper which teaches how to select a filter membrane, teaches that filter membranes can be symmetric or asymmetric, types of membrane filters, lists commonly used materials for microfilters, and thicknesses. It would have been obvious to one of ordinary skill in the art to look up relevant literature to find suitable materials and other details for specific applications when the primary reference is silent on such details. It would have been obvious to make simple substitutions, or combine the teachings of references to arrive at predictable results. MPEP 2143 -I, A-G. Rationales for combining references. Claim(s) 1, 3-5, 9, 10, 12-14, 16, 17, 20, 21, 23 and 29 are rejected under 35 U.S.C. 102(a1) as being anticipated by, or in the alternative, under 35 USC 103 as unpatentable over, Soules (WO 87/01301.) Soules teaches a spiral wound pleated filter as claimed. Pleats are clearly seen in fig. 5 and 5B copied herein, formed by media layers being bonded on alternate sides (faces) to form pleats. All inlets of pleats are on one face (top) and all outlets of the pleats are on the opposing face (bottom.) There are multiple windings. The intended use is for air (a fluid) filtration – see abstract. Multiple filter layers – see page 7, lines 3-6. The filter layer comprises pleated spacer layers as well, of thickness 200-2000 microns (page 8.) PNG media_image3.png 680 553 media_image3.png Greyscale PNG media_image4.png 786 444 media_image4.png Greyscale Applicant’s attention is directed to figures 5 and 5B of Soules. It is clear from that figure that the first and second filter membranes face each other, as claimed, but separated by spacers as disclosed. Filter material includes polyamide/nylon – page 7, material sufficient to remove fine particles. Claims 11 and 12: Soules is silent of symmetric or asymmetric, but since both are claimed, these are not patentable. Claim 14: surface area required is not patentable but would depend on the size or capacity of the filter desired – obvious. Claim(s) 1, 3-7, 9, 16, 17, 20, 21 and 29 are rejected under 35 U.S.C. 102a1 as being clearly anticipated by Reiman et al (US 3,962,097), submitted by applicant in an IDS on 1/6/26 PNG media_image5.png 394 637 media_image5.png Greyscale Reiman, figure 2, copied herein clearly shows the filter as claimed. The spiral wound pleated filter is formed by filter layers 7 and 8 and spacer layers 5 and 6. The material of filter, spacer and the adhesive are polypropylene, polyester, etc. Thickness of the spacer is within the claimed range. Inlet 28, outlet 37, and the fluids pass through axial direction from inlet to outlet as claimed. Response to Arguments Arguments directed at Weyand are trying to differentiate between applicant’s single stage vs. Weyand’s multi-stage filter, and are not persuasive because applicant’s claims do not exclude multi-stage filter. Even if so amended to exclude muti-stage, the claims would not become patentable since such staging are well-known and commonly practiced in the industry. Regarding Soules, Soules in fig. 5 teaches spacer layers 20 and 21, both are or can be permeable (page 13, lines 33-34.). Applicant appears to argue that their spacer is not pleated, whereas Soule’s spacer is pleated. The pleated construction is still permeable an provide the “continuous inlet space” claimed. Regarding Reiman not teaching the inlet pleat and outlet pleat is not persuasive. Reiman shows the exact same structure as in applicant’s fig. 1. Conclusion THIS ACTION IS MADE FINAL. 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 KRISHNAN S MENON whose telephone number is (571)272-1143. The examiner can normally be reached Flexible, but generally Monday-Friday: 8:00AM-4:30PM. 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, Prem C Singh can be reached at 571-272-6381. 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. /KRISHNAN S MENON/Primary Examiner, Art Unit 1777
Read full office action

Prosecution Timeline

Show 2 earlier events
Oct 13, 2025
Response Filed
Nov 03, 2025
Final Rejection mailed — §102, §103, §Other
Jan 05, 2026
Response after Non-Final Action
Feb 03, 2026
Request for Continued Examination
Feb 06, 2026
Response after Non-Final Action
Apr 14, 2026
Non-Final Rejection mailed — §102, §103, §Other
Jul 14, 2026
Response Filed
Jul 29, 2026
Final Rejection mailed — §102, §103, §Other (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

5-6
Expected OA Rounds
60%
Grant Probability
71%
With Interview (+11.5%)
3y 3m (~0m remaining)
Median Time to Grant
High
PTA Risk
Based on 1505 resolved cases by this examiner. Grant probability derived from career allowance rate.

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