Prosecution Insights
Last updated: April 19, 2026
Application No. 18/224,806

Feedstock Solution Flow Concentration System

Non-Final OA §103
Filed
Jul 21, 2023
Examiner
MENON, KRISHNAN S
Art Unit
1777
Tech Center
1700 — Chemical & Materials Engineering
Assignee
Asahi Kasei Kabushiki Kaisha
OA Round
3 (Non-Final)
60%
Grant Probability
Moderate
3-4
OA Rounds
3y 2m
To Grant
71%
With Interview

Examiner Intelligence

Grants 60% of resolved cases
60%
Career Allow Rate
879 granted / 1475 resolved
-5.4% vs TC avg
Moderate +12% lift
Without
With
+11.7%
Interview Lift
resolved cases with interview
Typical timeline
3y 2m
Avg Prosecution
72 currently pending
Career history
1547
Total Applications
across all art units

Statute-Specific Performance

§101
1.7%
-38.3% vs TC avg
§103
31.5%
-8.5% vs TC avg
§102
29.4%
-10.6% vs TC avg
§112
26.4%
-13.6% vs TC avg
Black line = Tech Center average estimate • Based on career data from 1475 resolved cases

Office Action

§103
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 § 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. Claims 13, 14, 16-20, 22, 23, 25-31 and 34 are rejected under 35 U.S.C. 103 as unpatentable over Bradley US 3,707,231, with evidence from KR 20160080376A and Kim et al Desalination 352 (2014) 128–135, with further evidence from McGinnis et al (US 2011/0203994). Bradley teaches a forward osmosis and a reverse osmosis combination method to purify feedstock. See the figure copied herein. Concentrated draw solution is obtained by reverse osmosis in Bradley, which is mixed with the draw solution in the forward osmosis membrane. Feedstock in Bradley is contaminated water, brackish water or seawater. Bradley’s intermediate solution (i.e., the draw solution) is listed in col. 7, lines 34-68, and magnesium sulfate solution, but can include several other solutes listed including organic solutes and sodium chloride, or it can be concentrated seawater. Therefore, the feed solution and the draw solution in Bradley have as common solutes if seawater is the feed and magnesium sulfate and sodium chloride are the draw solutes. Magnesium sulfate has a molecular weight > 100. PNG media_image1.png 526 859 media_image1.png Greyscale However, considering only magnesium sulfate as the draw solute and seawater as the feedstock, the forward osmosis process while passing the water through the membrane from seawater to draw solution, would also pass the salt (sodium chloride) in the sweater in the same direction due to its concentration difference, higher concentration of salt in seawater compared to that of the draw solution. Thus, the draw solution in Bradley inherently would contain salt as a common solute. The concentration of the salt build-up in the draw solution would increase with time to an equilibrium level that is less than or equal to the concentration of salt in the seawater, meeting the requirements in these claims. This is an inherent nature of the forward osmosis process, and would have been obvious to one of ordinary skill in the art. Evidence that membrane permeates salt is provided by the applicant in [0001 – 0007] of the specification. Applicant sites two patent literatures, the first one having a concentrated feed solution as the draw solution (as in Bradley, concentrated seawater as draw solution), and the second one having the membrane permeable feed solute in the draw solution at a higher concentration. What these two patent literature would suggest to one of ordinary skill in the art, who would also know that salts do permeate the membrane and the salt flux is driven by the concentration difference, that the permeable solute concentration can be optimized to make the net common solute permeation rate to zero, by adjusting the concentrations of the common solute in the feedstock and draw solutions. Since the solutes are not removed from the draw solution in the Bradley process, but continuously concentrated by reverse osmosis, the salt concentration in it would eventually equilibrate to a concentration wherein the net salt flux across the forward osmosis membrane would be zero. For these reasons, the concentration of the common solute between the feedstock and the draw solution would have been obvious to one of ordinary skill in the art. As further evidence for the determination of feed solute flux (salt flux) in FO, please see the NPL by Kim. Response to the amendment including pharmaceutical compositions, NaCl, KCl, iodides, lithium, calcium, magnesium, etc., found in seawater are pharmaceutical small molecules. Several of these exceed molecular weight of 100. Claims are considered under the broadest reasonable interpretation in the light of the specification. Applicant’s specification lists many compounds as solutes and common solutes under the umbrella of “pharmaceuticals” in [0032] – [0040]. Further evidence of using pharmaceuticals as solutes in the feed solution is provided by McGinnis, in a similar process of combination of forward osmosis and membrane distillation. See Fig. 4 and [0048-0050]. Claim 24, 32: the feedstock in Bradley is water, which is a food solution, a pharmaceutical ingredient,, etc. Water is consumed by humans in very many verities of forms. Note: this claim recites a pharmaceutical composition, not the solute. See also McGinnis for further evidence. For claims 22-31: The membrane is polyamide hollow fiber membrane module – see details in col. 6. Having a polyamide TCF membrane on polysulfone hollow fiber is well-known in the art. Having the active layer (polyamide) inside the lumen of the hollow fiber, the examiner believes there is no difference whether it is on the inside or the outside of the lumen. Nonetheless, The KR reference teaches specifically hollow fiber membrane for use in forward osmosis which have polyamide active layer in the lumen (see claims 3 and 5). It would have been obvious to use the teaching of KR in the teaching of Bradley because one would look for missing information, or for more newer and better working products when considering an older reference. KR shows that TFC in the lumen performs better – examples and comparative examples. Claims 13, 14, 16-23, 25-31 and 34 are rejected under 35 U.S.C. 103 as being unpatentable over Desormeaux et al (US 2017/0232392), with evidence from KR 20160080376 and Kim et al Desalination 352 (2014) 128–135, with further evidence from McGinnis et al (US 2011/0203994). Desormeaux teaches a combination of forward osmosis and membrane distillation methods, as in claims 13 and 21, for seawater purification – see the figures, abstract and [0026]. Draw solute preferred in magnesium chloride and/or calcium chloride. Id. The membrane is polyamide hollow fiber for FO [0024]. Membrane distillation concentrates the draw solution and provides pure water – [0027]. Desormeaux teaches optimizing the chemical composition the permeate in [0016]: “An advantage of an FO system combined with RO compared to traditional RO in some examples is that the chemical composition of the draw solution may be used to control the permeate composition. For example, if a low sodium permeate is desired, a magnesium chloride draw may be used.” [underline for emphasis] The concentration of common solute(s) in the feedstock and draw solutions can be optimized in the same way as analyzed in rejection 1. Desormeaux teaches the “Toyobo type” hollow fiber membrane for the purpose, which has the recited structure, and is commercially available (a screen capture of the Toyobo web site is provided herewith), but does not provide details of the hollow fiber membrane, but then as shown in rejection 1, it would have been obvious to use the teaching of KR for such details. Solutes and concentrations are not patentable in the apparatus claims as shown in rejection 1. Regarding the amendments, please see the details in rejection 1 above, which apply herein as well, including evidence from McGinnis. PNG media_image2.png 858 897 media_image2.png Greyscale Screen capture of Toyobo from << https://www.toyobo-global.com/seihin/hq/#cross>>. See the insert picture showing the dense separation layer in the lumen of the hollow fiber. Allowable Subject Matter Claims 33 and 35 are objected to as being dependent upon a rejected base claim, but would be allowable if rewritten in independent form including all of the limitations of the base claim and any intervening claims. Response to Arguments Applicant's arguments filed 10/3/25 have been fully considered but they are not persuasive. They are addressed in the rejection. Conclusion 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, Vickie Kim can be reached on 5712720579. 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

Jul 21, 2023
Application Filed
Sep 27, 2024
Non-Final Rejection — §103
Mar 25, 2025
Response Filed
Apr 04, 2025
Final Rejection — §103
Oct 03, 2025
Request for Continued Examination
Oct 06, 2025
Response after Non-Final Action
Oct 27, 2025
Non-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
60%
Grant Probability
71%
With Interview (+11.7%)
3y 2m
Median Time to Grant
High
PTA Risk
Based on 1475 resolved cases by this examiner. Grant probability derived from career allow rate.

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