Prosecution Insights
Last updated: April 19, 2026
Application No. 18/137,195

DEVICE FOR TANGENTIAL FLOW FILTRATION OF A FLUID

Non-Final OA §103§112
Filed
Apr 20, 2023
Examiner
FITZSIMMONS, ALLISON GIONTA
Art Unit
1773
Tech Center
1700 — Chemical & Materials Engineering
Assignee
Levitronix GmbH
OA Round
1 (Non-Final)
47%
Grant Probability
Moderate
1-2
OA Rounds
3y 6m
To Grant
64%
With Interview

Examiner Intelligence

Grants 47% of resolved cases
47%
Career Allow Rate
288 granted / 608 resolved
-17.6% vs TC avg
Strong +16% interview lift
Without
With
+16.5%
Interview Lift
resolved cases with interview
Typical timeline
3y 6m
Avg Prosecution
30 currently pending
Career history
638
Total Applications
across all art units

Statute-Specific Performance

§101
0.5%
-39.5% vs TC avg
§103
46.0%
+6.0% vs TC avg
§102
20.2%
-19.8% vs TC avg
§112
29.4%
-10.6% vs TC avg
Black line = Tech Center average estimate • Based on career data from 608 resolved cases

Office Action

§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 Election/Restrictions Claims 10-17 are withdrawn from further consideration pursuant to 37 CFR 1.142(b) as being drawn to a nonelected inventions, there being no allowable generic or linking claim. Election was made without traverse in the reply filed on 12/17/2025. 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. Claim 1 is 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: it is unclear how the pump can convey fluid from the reservoir to the filter unit when the filter unit comprises the reservoir, i.e. the filter unit is the entirety of the system. 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. The factual inquiries 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 1-8 are rejected under 35 U.S.C. 103 as being unpatentable over Doud (USP 4844932) and further in view of Taniguichi et al. (US Pub. No. 2014/0284929). Claims 1 and 5: Daoud teaches A device for tangential flow filtration of a fluid, comprising a filter unit (Fig. 2) having a first fluid opening (line into 13) and a second fluid (line out of 13) opening for the fluid, a filter element (13) and a permeate opening (9) to discharge a permeate filtered out of the fluid; a first flow connection (see annotated figure below) to connect the first fluid opening to a reservoir (10) for the fluid; a second flow connection (see annotated figure) to connect the second fluid opening to the reservoir for the fluid; a first pump (12) in the first flow connection, and configured to convey the fluid from the reservoir to the filter unit; a third flow connection configured to enable a fluid communication between the first flow connection and the second flow connection, the third flow connection bypassing the filter unit (see annotated figure). Daoud does not teach a second pump configured to circulate the fluid through the third flow connection and the filter unit. Taniguchi et al. teach a filtration system comprising a pump (Fig. 8, 18) in a filter bypass line (L11). The bypass pump is used to control flow of fluid through the bypass line [0085]. One of ordinary skill in the art at the time of the invention would have found it obvious to include a pump in the third flow connection of Daoud for the benefit of controlling the fluid flow through the third flow connection. Claim 2: Daoud teaches the device according to claim 1, further comprising a first branching point arranged at the first flow connection, and a second branching point arranged at the second flow connection, the third flow connection extending from the first branching point to the second branching point, and the first branching point disposed between the first pump and the first fluid opening of the filter unit (See annotated Figure 2 above; valves are the double triangle element in the line which is clear from Fig. 4, 60 which is depicted the same way and is titled a valve). Claim 3: Daoud teaches a first flow controller configured to open or close a passage through the third flow connection (see valve in the third flow connection bypass line; see annotated Figure 2 above; valves are the double triangle element in the line which is clear from Fig. 4, 60 which is depicted the same way and is titled a valve). Claim 4: Daoud teaches a second flow controller configured to open or close a passage through the second flow connection (Fig. 2, valve adjacent to filter 13, see annotated figure above). Daoud does not teach that the second flow controller is disposed between the second branching point and the reservoir. However, the use of valves to control fluid flow is well-known in the art. One of ordinary skill in the art at the time of the invention would have found it obvious to include a valve in the line between the second branching point and the reservoir for the benefit of enabling additional fluid control in the filtration system. Claim 6: Daoud does not teach the absence of a flow controller in the bypass line so that the third flow connection is “always open during operation”. Daoud teaches a flow controller, i.e. a valve in the bypass line. However, the valve can be kept open as valves can be open or closed. Claiming the absence of a valve does not establish over the prior art that teaches a valve wherein the valve can be kept open and accomplish the same goal of having a flow connection “always open during operation”. Claim 7: Daoud does not teach a flow controller between the second branching point and the reservoir. Claim 8: Daoud does not teach a second pump arranged between the second branding point and the second fluid opening of the filter unit. Taniguichi et al. teach a permeate pump disposed in the permeate line (Fig. 3, 17). The permeate pump allowed for control of the fluid in the permeate line. One of ordinary skill in the art at the time of the invention would have found it obvious to include a pump in the permeate line for the benefit of fluid flow control. Claim 9 is rejected under 35 U.S.C. 103 as being unpatentable over Doud (USP 4844932) and Taniguichi et al. (US Pub. No. 2014/0284929) in further view of Blankemeir et al. (USP 8905729). Claim 9: Doud and Taniguichi et al. do not teach the first and second pumps are specific the electromagnetic rotary vane pumps recited in Claim 9. They do not teach any specific type of pump. Blankemeier et al. teach an electromagnetic rotary pump comprising a casing (4), an inlet (204) and an outlet (206), vanes (242), a rotor, and a stator (col. 9, lines 1-5). The pump moves axially (Col. 10, lines 25-30). This type of pump avoids rotating seals (col. 1, lines 11-13) which prevents leakage and contamination. One of ordinary skill in the art at the time of the invention would have found it obvious to use Blankemeier et al.’s specific electromagnetic rotary pump as Daoud’s first and second pumps to obviate seals and prevent leakage and fluid contamination. Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to ALLISON FITZSIMMONS whose telephone number is (571)270-1767. The examiner can normally be reached M-F 9:30 am - 2:00 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, Benjamin Lebron can be reached at (571)272-0475. 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. ALLISON FITZSIMMONS Primary Examiner Art Unit 1773 /ALLISON G FITZSIMMONS/ Primary Examiner, Art Unit 1773
Read full office action

Prosecution Timeline

Apr 20, 2023
Application Filed
Feb 02, 2026
Non-Final Rejection — §103, §112 (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
47%
Grant Probability
64%
With Interview (+16.5%)
3y 6m
Median Time to Grant
Low
PTA Risk
Based on 608 resolved cases by this examiner. Grant probability derived from career allow rate.

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