Prosecution Insights
Last updated: April 19, 2026
Application No. 17/999,928

Personal protection equipment (PPE)) for air purification

Final Rejection §103
Filed
Nov 27, 2022
Examiner
KHONG, BRIAN THAI-BINH
Art Unit
3785
Tech Center
3700 — Mechanical Engineering & Manufacturing
Assignee
Prasanna Dinkar Sohale
OA Round
2 (Final)
66%
Grant Probability
Favorable
3-4
OA Rounds
3y 1m
To Grant
99%
With Interview

Examiner Intelligence

Grants 66% — above average
66%
Career Allow Rate
187 granted / 283 resolved
-3.9% vs TC avg
Strong +37% interview lift
Without
With
+36.9%
Interview Lift
resolved cases with interview
Typical timeline
3y 1m
Avg Prosecution
18 currently pending
Career history
301
Total Applications
across all art units

Statute-Specific Performance

§101
3.6%
-36.4% vs TC avg
§103
41.7%
+1.7% vs TC avg
§102
17.8%
-22.2% vs TC avg
§112
27.0%
-13.0% vs TC avg
Black line = Tech Center average estimate • Based on career data from 283 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 . Priority Acknowledgment is made of applicant's claim for foreign priority based on an application filed in the Republic of India on May 27, 2020. It is noted, however, that applicant has not filed a certified copy of the IN 202021022111 application as required by 37 CFR 1.55. Drawings The drawings are objected to because: The reference character “120” is not found in the specification (Fig 1). Corrected drawing sheets in compliance with 37 CFR 1.121(d) are required in reply to the Office action to avoid abandonment of the application. Any amended replacement drawing sheet should include all of the figures appearing on the immediate prior version of the sheet, even if only one figure is being amended. The figure or figure number of an amended drawing should not be labeled as “amended.” If a drawing figure is to be canceled, the appropriate figure must be removed from the replacement sheet, and where necessary, the remaining figures must be renumbered and appropriate changes made to the brief description of the several views of the drawings for consistency. Additional replacement sheets may be necessary to show the renumbering of the remaining figures. Each drawing sheet submitted after the filing date of an application must be labeled in the top margin as either “Replacement Sheet” or “New Sheet” pursuant to 37 CFR 1.121(d). If the changes are not accepted by the examiner, the applicant will be notified and informed of any required corrective action in the next Office action. The objection to the drawings will not be held in abeyance. Claim Objections Claims 1-3 and 7 are objected to because of the following informalities: The phrase “breaths” should be changed to –breathes—to correct the grammatical error (Claim 1, Line 4). The phrase “the air” should be changed to –the filtered air—for consistency (Claim 1, Line 8; Claim 2, Line 1). The phrase “sent” should be changed to –sent to— to correct the grammatical error (Claim 1, Line 9). The phrase “a water” should be changed to –water—to correct the grammatical error (Claim 3, Line 2). The phrase “bacteria and virus from the air before it reaches mouth” should be changed to –bacteria and viruses from the air before they reach a mouth—to correct the grammatical errors (Claim 7, Line 2). Appropriate correction is required. 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 (i.e., changing from AIA to pre-AIA ) 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 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 1-2 and 4-7 are rejected under 35 U.S.C. 103 as being unpatentable over Choi (US 2018/0015310 A1) in view of Zhu (US 2017/0106333 A1). Regarding Claim 1, Choi discloses a personal protection equipment (PPE) (apparatus of Fig 1) for air purification (portable air purifier, Abstract), the PPE comprising: an apparatus comprising: a filter (pre-filter 24, Figs 1-3) that is configured to filter the air for removing dust from the air (primary contaminant filtered out by pre-filter 24, paragraph 0038; the user may conveniently carry the portable air purifier regardless of place in preparation for atmospheric pollution, yellow dust, fine dust, paragraph 0037; the filter would be capable of removing some forms of dust from the air); and a scrubber unit (10c, W, 26, and 26a, Fig 2) that is configured to purify the air before a user breaths the air (the ultra-fine dust included in the air is separated from the air and floats in the water W, and purified, humidified air, from which the ultra-fine dust has been separated, is discharged to the outside via the cannula, paragraph 0036), wherein the scrubber unit comprises: a sparger (26a, Fig 2) through which the filtered air is pumped and bubbled in water to trap remaining contaminants in the air (the air passing through the siphon pipe 26 forms fine bubbles B while diffusing through the water W filling the third accommodation portion 10c via the diffuser 26a installed on the bottom of the siphon pipe 26, while these bubbles B are slowly floating to the surface of the water W and are bursting, ultra-fine dust included in the air is secondarily separated, paragraph 0035) and the contaminants free or improved quality air is sent the user for breathing (purified, humidified air, from which the ultra-fine dust has been separated, is discharged to the outside via the cannula, a user can inhale the purified, humidified air by bringing the cannula 28 close to the nasal cavity or oral cavity, paragraph 0036). Choi fails to disclose a water solution of polymer. However, Zhu, of the same field of endeavor, teaches the removal and control of pollutant in an enclosed space or an outdoor environment (Abstract) including the use of a water solution of polymer (Table 1 lists various disinfectants/biocides/sterilants including polymeric biguanides, Pages 8-9) since these are known disinfectants/biocides/sterilants that can be dissolved in an aqueous sparging solution (Table 1, Pages 8-9) and since these substances are known to kill pathogens (paragraph 0113). Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to add one or more disinfectants/biocides/sterilants, such as polymeric biguanides, into the water, as taught by Zhu, since these are known disinfectants/biocides/sterilants that can be dissolved in an aqueous sparging solution (Zhu: Table 1, Pages 8-9) and since these substances are known to kill pathogens (Zhu: paragraph 0113). Adding these polymeric biguanides would enhance the effectiveness of the water to remove any additional contaminants from the air, including microorganisms or pathogens. This would ensure the air being provided to the user would be clean, disinfected air. Regarding Claim 2, Choi-Zhu combination teaches the air is sent to the scrubber unit through a first tube (Choi: 40, Figs 1-2). The current combination of Choi-Zhu combination fails to teach the tube is flexible. However, Zhu further teaches the tube is flexible (exit port can be fitted with a flexible conduit to direct captured air to absorbent media, paragraph 0126; conduit refers to means for transferring air such as hoses, tubing [plastic, tygon or rubber], paragraph 0107) since these are known tubes capable of transferring air. Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the tube to be flexible, as taught by Zhu, since these are known tubes capable of transferring air. Having a flexible tube would also allow for easier disassembly of components. Regarding Claim 4, Choi-Zhu combination teaches the contaminants free air is sent to the user through a second tube (Choi: tubing of 28, Fig 2) and a face mask (Choi: the cannula 28 may be directly worn in the nasal cavity or oral cavity, or may be connected to and used in connection with a mask, paragraph 0032). The current combination of Choi-Zhu combination fails to teach the tube is flexible. However, Zhu further teaches the tube is flexible (exiting vessel delivered to individual via tubing connected to a face mask, paragraph 0063; conduit refers to means for transferring air such as hoses, tubing [plastic, tygon or rubber], paragraph 0107) since these are known tubes capable of transferring air. Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the tube to be flexible, as taught by Zhu, since these are known tubes capable of transferring air. Having a flexible tube would also allow for easier use especially if the user is positioned in another place. Additionally, it is well-known for face masks and cannulas to use flexible tubes for easier positioning. Regarding Claim 5, Choi-Zhu combination teaches the PPE comprises a battery to operate the scrubber unit (Choi: 20, Fig 2; control box 36 electrically connect to and control battery 20, 22, 30, and 32, paragraph 0025; device is inherently operated by battery 20). Regarding Claim 6, Choi-Zhu combination teaches the air is inputted to an air pump unit (Choi: 22, Fig 2) for removal of the dust from the air (Choi: a contaminant included in external air is primarily filtered out while the external air is passing through the pre-filter 24 via the cover mesh member 16, and the filtered air is compressed via the air compressor 22, paragraph 0034; primary contaminant is filtered out by the pre-filter 24 while external air is being sucked by the air compressor 22, paragraph 0038). Regarding Claim 7, Choi-Zhu combination teaches the PPE removes bacteria and virus from the air before it reaches mouth or nostrils of the user (Zhu: biocide”, “disinfectant” and “sterilant” refers to one or more additives that can be added to the absorbable media to kill, control, or prevent mites, bacteria and their spores, fungi, molds, mildew and viruses, prolonging the service time of the media and stop the spread or distribution of pathogens that cause infectious diseases, paragraph 0113; Table 1 lists various disinfectants/biocides/sterilants including polymeric biguanides, Pages 8-9; the presence of these substances would obviously kill bacteria and viruses before the air reaches the user). Claim 3 is rejected under 35 U.S.C. 103 as being unpatentable over Choi (US 2018/0015310 A1) and Zhu (US 2017/0106333 A1) as applied to Claim 1, and in further view of Fornai et al. (US 6,843,835 B2). Regarding Claim 3, Choi-Zhu combination teaches the claimed invention of Claim 1. Choi-Zhu combination also teaches the water solution of polymer comprises a water (Choi: W, Fig 2; water W, paragraph 0023), a solution with chemicals to detoxify (Zhu: biocide”, “disinfectant” and “sterilant” refers to one or more additives that can be added to the absorbable media to kill, control, or prevent mites, bacteria and their spores, fungi, molds, mildew and viruses, prolonging the service time of the media and stop the spread or distribution of pathogens that cause infectious diseases, paragraph 0113; Table 1 lists various disinfectants/biocides/sterilants including polymeric biguanides, Pages 8-9). Choi-Zhu combination fails to teach a packed column. However, Fornai, of the same field of endeavor and reasonably pertinent to the problem of purifying air, teaches an air cleaning apparatus (Abstract) including a packed column (packed column scrubbers that bring air and liquid in contact via solid material filling of the column, Column 3, Lines 6-9; packed column scrubber, Column 3, Lines 15-23) to help the air contact with the scrubbing liquor or solution (Column 2, Lines 63-65). Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to add a packed column into the chamber with water solution, as taught by Fornai, to help the air contact with the scrubbing liquor or solution (Fornai: Column 2, Lines 63-65). The use of the packed column would help enhance air-liquid contact to ensure all pollutants and contaminants are extracted from the air. Conclusion The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. See PTO-892 for art cited of interest including: US 20100263672 A1 discusses a liquid container and blower that filters air by pumping it through water. US 6799573 B1 discusses an air filtration system that filters the air through water and sends it to a mask. Any inquiry concerning this communication or earlier communications from the examiner should be directed to BRIAN THAI-BINH KHONG whose telephone number is (571)272-1857. The examiner can normally be reached Monday to Thursday 9:00 am-6:00 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, Kendra Carter can be reached at (571) 272-9034. 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. /BRIAN T KHONG/Examiner, Art Unit 3785 /JOSEPH D. BOECKER/Primary Examiner, Art Unit 3785
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Prosecution Timeline

Nov 27, 2022
Application Filed
Aug 06, 2025
Non-Final Rejection — §103
Nov 07, 2025
Response Filed
Dec 22, 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
66%
Grant Probability
99%
With Interview (+36.9%)
3y 1m
Median Time to Grant
Moderate
PTA Risk
Based on 283 resolved cases by this examiner. Grant probability derived from career allow rate.

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