Prosecution Insights
Last updated: April 19, 2026
Application No. 18/391,603

BACK FLOW PREVENTER

Non-Final OA §102§103
Filed
Dec 20, 2023
Examiner
CAHILL, JESSICA MARIE
Art Unit
3753
Tech Center
3700 — Mechanical Engineering & Manufacturing
Assignee
Robo-Fit LLC
OA Round
3 (Non-Final)
78%
Grant Probability
Favorable
3-4
OA Rounds
2y 6m
To Grant
99%
With Interview

Examiner Intelligence

Grants 78% — above average
78%
Career Allow Rate
627 granted / 801 resolved
+8.3% vs TC avg
Strong +23% interview lift
Without
With
+23.3%
Interview Lift
resolved cases with interview
Typical timeline
2y 6m
Avg Prosecution
31 currently pending
Career history
832
Total Applications
across all art units

Statute-Specific Performance

§101
0.1%
-39.9% vs TC avg
§103
39.3%
-0.7% vs TC avg
§102
30.2%
-9.8% vs TC avg
§112
28.9%
-11.1% vs TC avg
Black line = Tech Center average estimate • Based on career data from 801 resolved cases

Office Action

§102 §103
DETAILED ACTION Claims 1-20 were filed with the amendment dated 01/07/2026. 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 . Continued Examination Under 37 CFR 1.114 A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on 01/07/2026 has been entered. Response to Arguments Applicant’s amendments have overcome the previously set forth 35 USC 112 rejection. Applicant's arguments filed 01/07/2026 have been fully considered but they are not persuasive. With regard to claim 1, Applicant argues that because U.S. Pat. Pub. No. 2021/0172157 (“Burke”) discloses that the relief valve (vent assembly 108) relies on position sensors to determine opening of valve 108 (see Remarks at page 8 and 9), Burke does not teach all of the claimed requirements. Specifically, Applicant argues that Burke does not teach the “vent assembly controlling venting.” The examiner respectfully disagrees. The phrase “vent assembly” is a broad phrase that can include the sensors and controller. There is no claim language limiting the vent assembly so that the assembly cannot include sensors, a controller, or other features. In response to applicant's argument that the references fail to show certain features of the invention, it is noted that the features upon which applicant relies (i.e., “the structure of Burke is not self-contained or mechanically reactive”) are not recited in the rejected claim(s). Although the claims are interpreted in light of the specification, limitations from the specification are not read into the claims. See In re Van Geuns, 988 F.2d 1181, 26 USPQ2d 1057 (Fed. Cir. 1993). In response to applicant's argument that the references fail to show certain features of the invention with regard to claim 8 (see Remarks at page 10, lines 4-8), it is noted that the features upon which applicant relies (i.e., “the check valve be a self-contained, inline check valve mounted coaxially” for claim 8) are not recited in the rejected claim(s). Although the claims are interpreted in light of the specification, limitations from the specification are not read into the claims. See In re Van Geuns, 988 F.2d 1181, 26 USPQ2d 1057 (Fed. Cir. 1993). Claim 8 merely requires that “the primary check valve is mounted in a recess defined in the central section at an outlet end of the central section adjacent the outlet section” which is met by Burke. Burke discloses the primary check valve 110b mounted in a recess shown in annotated Fig 1b that is in the central section adjacent an outlet end (right end). PNG media_image1.png 660 1148 media_image1.png Greyscale In response to applicant's argument that the references fail to show certain features of the invention with regard to claim 9 (see Remarks at page 10, lines 9-19, it is noted that the features upon which applicant relies (i.e., “specific type of modular, self-contained, inline check valve this is press-fit or sealed by axial abutment from the outlet section as claimed” are not recited in the rejected claim(s). Although the claims are interpreted in light of the specification, limitations from the specification are not read into the claims. See In re Van Geuns, 988 F.2d 1181, 26 USPQ2d 1057 (Fed. Cir. 1993). Claim 9 merely requires “wherein the primary check valve is retained in the recess of the central section by a part of the outlet section that abuts the primary check valve.” With regard to claim 11, Applicant argues that Burke does not disclose that the fluid is “mechanically deterred” from passing through the secondary check valve (see Remarks at page 10, line 21 to page 11, line 3). Applicant argues that because Burke relies on sensor outputs or controller instructions, claim 11 is not met. The examiner respectfully disagrees. Claim 11 merely requires that “fluid is mechanically deterred from passing through the secondary check valve and fluid exits through the vent assembly and the vent opening.” This broad language is met by Burke. When the vent assembly (108) opens, the opening is mechanical and the opening mechanically deters fluid out of the vent assembly. With regard to claim 13, Applicant argues that “the secondary check valve is spaced from the primary check valve to define a fluid region in the internal passageway that enables primary check valve failure detection and activation of the vent assembly” (see Remarks at page 11, lines 4-6) is not met by Burke. The examiner respectfully disagrees. Burke discloses that the secondary check valve (110a) is spaced from the primary check valve (110b). As so broadly recited, the spacing and fluid region enables failure detection by having necessary space for sensors and controller, by having a space for the vent assembly (108) to be positioned between the check valves so that fluid exiting the valve also provides another indication of failure. With regard to claims 2 and 3, Applicant argues that the rejection over Burke in view of Speer (U.S. Pat. Pub. No. 2005/0072477) is improper (see Remarks at page 11, lines 10-30). Applicant argues that claims 2-3 require push-to-connect components, and that Burke discloses flanged valve installation likely requiring external piping connections and that Speer relates to connect air lines and not water lines. In response to applicant's argument that Speer is not analogous, it has been held that a prior art reference must either be in the field of the inventor’s endeavor or, if not, then be reasonably pertinent to the particular problem with which the inventor was concerned, in order to be relied upon as a basis for rejection of the claimed invention. See In re Oetiker, 977 F.2d 1443, 24 USPQ2d 1443 (Fed. Cir. 1992). In this case, Speer is reasonably pertinent because Speer merely discloses well-known connection mechanisms (push-to-connect). Furthermore, the teachings of Speer would not need to be bodily incorporated into Burke. Rather, the general teaching of the include recessed openings at inlet and outlet ends and inlet and outlet connectors in each of the recessed openings (see para [0020] and 30/31/32/33 of Speer) is what is being relied upon. The test for obviousness is not whether the features of a secondary reference may be bodily incorporated into the structure of the primary reference; nor is it that the claimed invention must be expressly suggested in any one or all of the references. Rather, the test is what the combined teachings of the references would have suggested to those of ordinary skill in the art. See In re Keller, 642 F.2d 413, 208 USPQ 871 (CCPA 1981). With regard to claim 10, in response to applicant's argument that the references fail to show certain features of the invention, it is noted that the features upon which applicant relies (i.e., potable beverage dispensing systems that operate at higher working pressures…with permanently mounted, functionally distinct primary and second check valves (see Remarks at page 12, lines 1-13) are not recited in the rejected claim(s). Although the claims are interpreted in light of the specification, limitations from the specification are not read into the claims. See In re Van Geuns, 988 F.2d 1181, 26 USPQ2d 1057 (Fed. Cir. 1993). In response to applicant's argument that the combination of Burke and Stauder (with respect to claim 10) would require a substantial reconfiguration (see Remarks at page 12, lines 14—21), the test for obviousness is not whether the features of a secondary reference may be bodily incorporated into the structure of the primary reference; nor is it that the claimed invention must be expressly suggested in any one or all of the references. Rather, the test is what the combined teachings of the references would have suggested to those of ordinary skill in the art. See In re Keller, 642 F.2d 413, 208 USPQ 871 (CCPA 1981). With regards to claims 12 and 14-15, Applicant argues that Cellemme discloses that both check valves close and the vent opens to atmosphere so that Cellemme is activated during normal hydraulic behavior (see Remarks at page 12, lines 22-31). Applicant further argues that the claims require “a vent assembly that is activated only when the primary check valve fails, which is a critical distinction.” However, the examiner respectfully disagrees. Cellemme is merely relied upon for claim 12 for teaching the structure of the check valve – specifically a diaphragm valve. Cellemme is not relied upon for the vent assembly. With regard to claim 14, Applicant contents that Burke (as modified by Cellemme) fails to teach that the sections are coupled together with screw threads, with screw threads being limited to two threaded joints between the inlet, central, and outlet sections to facilitate modular disassembly and independent replacement or repair of each section (see remarks at page 13, lines 6-15). Cellemme is relied upon for teaching the use of threaded connections. If those threaded connections are applied to Burke, there would be threaded connections between the inlet and central and then also the outlet and central – thus providing two threaded joints. With regard to claim 16, Applicant argues that the combination of Burke and Hecking does not teach the feature of “the vent opening is positioned closer to the inlet” (see Remarks at page 13, lines 16-21). The examiner respectfully disagrees. Hecking teaches that it is known in the art to modify a check valve assembly with a vent opening having the vent opening (20) positioned closer to the inlet (12) than the outlet (14) (see Fig. 1). The rejections are maintained. Claim Rejections - 35 USC § 102 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 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. Claims 1, 8, 9, 11, and 13 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by U.S. Pat. Pub. No. 2021/0172157 (“Burke”). With regard to claim 1, Burke discloses a back flow preventer (100, Fig. 1a-1b) comprising: a housing (show, not labeled, see annotated Fig) having an inlet section (section from inlet opening to opening at valve seat for 110a) defining an inlet (inlet opening at left, see annotated Fig) (flow direction is shown by arrows with “F”), a central section (section between valve seat opening for 110a, 110b), and an outlet section (section from valve seat opening 110b to outlet opening at right, see annotated Fig) defining an outlet (opening at right end, see annotated Fig), with the inlet section, central section and outlet section being coupled together and axially aligned with one another along a longitudinal axis (see annotated Fig); an internal passageway (passageway shown in Fig 1b, see annotated fig) defined through the housing between the inlet (left opening) and the outlet (right opening); a primary check valve (110b) positioned in the housing and coupled between the central section and the outlet section in the internal passageway (see annotated Fig); a secondary check valve (110a) positioned in the housing and coupled between the central section and the inlet section in the internal passageway (see annotated Fig); and a failure specific vent assembly (108) positioned in the central section (see annotated Fig) and coupled to a vent opening (opening through which water drains out), the vent assembly controlling venting from the internal passageway so that venting occurs only when the primary check valve fails (“the relief valve assembly 108 may open to release water if the second check assembly 110b should fail to prevent backflow.” Para [0005]); wherein the primary check valve (110b) is retained in the housing independently from the secondary check valve (110a) (as shown in Fig 1b, primary check valve 110b is completely separate from and not contacting secondary check valve 110a). PNG media_image1.png 660 1148 media_image1.png Greyscale With regard to claim 8, Burke discloses that the primary check valve (110b) is mounted in a recess (see annotated Fig) defined in the central section at an outlet end (right end) of the central section adjacent the outlet section (see annotated Fig). With regard to claim 9, Burke discloses that the primary check valve (110b) is retained in the recess (see annotated Fig) of the central section by a part (part is cover portion with extending legs shown in Fig 1b that holds primary check valve 110b, see annotated Fig) of the outlet section that abuts the primary check valve (110b). With regard to claim 11, Burke discloses that during a back flow condition where the primary check valve (110b) has failed, fluid is deterred from passing through the secondary check valve (110a) (deterred because secondary check valve 110a is in a closed position) and fluid exits through the vent assembly and the vent opening (108) (para [0005]), indicating to a user that the primary check valve has failed (draining of water out of vent is considered to meet the requirement of “indicating to a user that the primary check valve has failed” because action of water leaking out indicates a failure). With regard to claim 13, Burke discloses that the secondary check valve (110a) is spaced from the primary check valve (110b) (shown in Fig 1b) to define a fluid region in the internal passageway (space between check valves 110a and 110b) that enables primary check valve failure detection and activation of the vent assembly (by having a space for the vent assembly (108) to be positioned between the check valves so that fluid exiting the valve also provides another indication of failure). 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. Claims 2 and 3 are rejected under 35 U.S.C. 103 as being unpatentable over U.S. Pat. Pub. No. 2021/0172157 (“Burke”) in view of U.S. Pat. Pub. No. 2005/0072477 (“Speer”). With regard to claim 2, Burke discloses all the claimed features with the exception of disclosing an inlet connector and an outlet connector, each of which is positioned in the respective recessed opening. Burke does disclose a recessed opening formed in the inlet and the outlet (see annotated Fig). Speer teaches that it is known in the art to modify a check valve assembly (abstract) to include recessed openings at inlet and outlet ends and inlet and outlet connectors in each of the recessed openings (see para [0020] and 30/31/32/33) for the purpose of connecting lines to the valve assembly 12. PNG media_image2.png 526 922 media_image2.png Greyscale It would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to utilize inlet and outlet connectors , such as taught by Speer, in the recessed openings of the inlet and outlet of Burke for the purpose of connecting fluid lines to the body (such as taught by Speer at para [0020]). With regard to claim 3, (claim 3 depends from claim 2) the combination of Burke and Speer as set forth above discloses the inlet connector (30/31/32/33) is a push- to-connect cartridge and the outlet connector (30/31/32/33) is a push-to-connect cartridge, and the inlet and outlet connectors are press-fit into their respective recessed openings (press-fit shown in Fig. 2 of Speer) (para [0020]: “These chambers, 25-27 receive a plug 30, a collet 31, a sleeve 32 and an O-ring 33, which form a push to connect cartridge assembly for connecting lines, such as 11, to the fitting 12.”). Claim 10 is rejected under 35 U.S.C. 103 as being unpatentable over U.S. Pat. Pub. No. 2021/0172157 (“Burke”) in view of U.S. Pat. Pub. No. 2011/0226357 (“Stauder”). With regard to claim 10, Burke discloses all the claimed features with the exception of disclosing the primary check valve is press fit into the recess of the central section. Stauder teaches that it is known in the art to modify a primary (downstream) check valve (see Fig. 5 showing two check valves 260, 260 in series) to be a press fit type check valve (Figs. 5 and 5a show that the check valve 260 is press fit into a central section). It would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to utilize a press fit check valve as taught by Stauder in place of the check valve of Burke, since the check valves are known equivalents and the use of which would be known to one of ordinary skill in the art. Claims 12, 14, and 15 are rejected under 35 U.S.C. 103 as being unpatentable over U.S. Pat. Pub. No. 2021/0172157 (“Burke”) in view of U.S. Pat. Pub. No. 2016/0178076 (“Cellemme”). With regard to claim 12, Burke discloses that the primary check valve (110b) is (as best understood) is a self-contained cracking pressure check valve (see Fig 1b). Burke discloses all the claimed features with the exception of disclosing that the secondary check valve is a diaphragm valve. Cellemme teaches that it is known in the art to provide a back flow preventer with a primary check valve, secondary check valve, and vent assembly, similar to that of Burke, and that it is known to have the secondary check valve be a diaphragm valve (diaphragm at 38). It would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to utilize a diaphragm check valve for a secondary check valve as taught by Cellemme in place of the secondary check valve of Burke, since the valves are known equivalents and the use of which would be known to one of ordinary skill in the art. With regard to claim 14, Burke discloses all the claimed features with the exception of disclosing the inlet section, central section, and outlet sections are coupled together by screw threads, with the screw threads being limited to two threaded joints between the inlet, central, and outlet sections to facilitate modular disassembly and independent replacement or repair of each section. Cellemme teaches that it is known in the art to provide a back flow preventer with a primary check valve, secondary check valve, and vent assembly, similar to that of Burke, and that it is known to have the inlet section (section with 14), central section (60), and outlet sections (section with 98) are coupled together by screw threads (paras [0033] [0036] [0040], see also Fig. 5). It would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to utilize a connection of inlet, central, and outlet sections of a valve assembly comprise screw threads in place of the coupling mechanism of Burke, since the valve housing assembly coupling mechanism are known equivalents and the use of which would be known to one of ordinary skill in the art. If those threaded connections are applied to Burke, there would be threaded connections between the inlet and central and then also the outlet and central – thus providing two threaded joints, which would meet the intended use of facilitating modular disassembly and independent repair or replacement. With regard to claim 15, Burke as modified by Cellemme above for claim 14 discloses external means for screwing the inlet, outlet, and central sections together (12 and 100; see paras [0036] [0040]). Claim 16 is rejected under 35 U.S.C. 103 as being unpatentable over U.S. Pat. Pub. No. 2021/0172157 (“Burke”) in view of U.S. Pat. Pub. No. 2007/0079873 (“Hecking”). With regard to claim 16, Burke discloses all the claimed features with the exception of disclosing the vent opening is positioned closer to the inlet than the outlet. Hecking teaches that it is known in the art to modify a check valve assembly with a vent opening having the vent opening (20) positioned closer to the inlet (12) than the outlet (14) (see Fig. 1). PNG media_image3.png 785 992 media_image3.png Greyscale Applicant has not disclosed that having the vent opening positioned closer to the inlet than the outlet solves any stated problem or is for any particular purpose. Rather, the specification states that this is just an option and “may” occur (“The vent opening may be positioned closer to the inlet than the outlet” (page 8, line 15 of the specification). Moreover, it appears that the vent opening would perform equally well at any location between the inlet and outlet. Accordingly, it would have been a matter of obvious design choice to one having ordinary skill in the art before the effective filing date of the claimed invention to make the vent opening of Burke positioned closer to the inlet than the outlet, such as taught by Hecking, because the position of the vent opening relative to inlet and outlet does not appear to provide any unexpected results. Allowable Subject Matter Claims 4-7 and 17-20 are allowed. The following is a statement of reasons for the indication of allowable subject matter: the prior art fails to disclose or render obvious “wherein the vent assembly includes a retaining element positioned in the internal passageway of the central section downstream of the secondary check valve for assisting in retaining the secondary check valve inside the internal passageway” (claim 4) or “the vent assembly including a retaining element positioned inside the internal passageway for retaining the secondary check valve in the housing” (claim 18) in combination with the other limitations set forth in the independent claims. Burke fails to teach or suggest that “the vent assembly includes a retaining element positioned in the internal passageway of the central section downstream of the secondary check valve for assisting in retaining the secondary check valve inside the internal passageway” (claim 4) or “the vent assembly including a retaining element positioned inside the internal passageway for retaining the secondary check valve in the housing” (claim 18) as required by claims 4 and 18. U.S. Pat. Pub. No. 2007/0079873 (“Hecking”) and U.S. Pat. Pub. No. 2016/0178076 (“Cellemme”) each disclose “the vent assembly includes a retaining element positioned in the internal passageway of the central section downstream of the secondary check valve for assisting in retaining the secondary check valve inside the internal passageway” (claim 4) or “the vent assembly including a retaining element positioned inside the internal passageway for retaining the secondary check valve in the housing” (claim 18). However, it would not have been obvious to modify Burke, Hecking and/or Cellemme (together or separately) to arrive at the required claim language without improper hindsight reasoning and without improperly changing the principle of operation of either reference. Conclusion The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. U.S. Pat. No. 4,284,097 discloses a dual check valve assembly. Any inquiry concerning this communication or earlier communications from the examiner should be directed to JESSICA CAHILL whose telephone number is (571)270-5219. The examiner can normally be reached Mon-Fri: 6:30 to 3:00. 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 supervisors can be reached by phone. Craig Schneider can be reached at 571-272-60073607 or Kenneth Rinehart can be reached at 571-272-4881. 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. /JESSICA CAHILL/Primary Examiner, Art Unit 3753
Read full office action

Prosecution Timeline

Dec 20, 2023
Application Filed
Jan 08, 2025
Non-Final Rejection — §102, §103
Jul 14, 2025
Response Filed
Oct 02, 2025
Final Rejection — §102, §103
Jan 07, 2026
Request for Continued Examination
Feb 03, 2026
Response after Non-Final Action
Feb 07, 2026
Non-Final Rejection — §102, §103 (current)

Precedent Cases

Applications granted by this same examiner with similar technology

Patent 12601410
FLUID CONTROL ASSEMBLY
2y 5m to grant Granted Apr 14, 2026
Patent 12584591
GAS SUPPLY SYSTEM
2y 5m to grant Granted Mar 24, 2026
Patent 12586705
DIVERTER DEVICE FOR TRANSFORMER FLUIDS
2y 5m to grant Granted Mar 24, 2026
Patent 12578062
ANTI-LEAKAGE DEVICE FOR HYDROGEN STORAGE CONTAINER
2y 5m to grant Granted Mar 17, 2026
Patent 12565939
ELECTRIC DIVERTER VALVE CAPABLE OF REALIZING ACCURATE FLOW CONTROL
2y 5m to grant Granted Mar 03, 2026
Study what changed to get past this examiner. Based on 5 most recent grants.

AI Strategy Recommendation

Get an AI-powered prosecution strategy using examiner precedents, rejection analysis, and claim mapping.
Powered by AI — typically takes 5-10 seconds

Prosecution Projections

3-4
Expected OA Rounds
78%
Grant Probability
99%
With Interview (+23.3%)
2y 6m
Median Time to Grant
High
PTA Risk
Based on 801 resolved cases by this examiner. Grant probability derived from career allow rate.

Sign in with your work email

Enter your email to receive a magic link. No password needed.

Personal email addresses (Gmail, Yahoo, etc.) are not accepted.

Free tier: 3 strategy analyses per month