Prosecution Insights
Last updated: April 19, 2026
Application No. 18/239,457

PREMIXING DEVICE FOR WATER HEATER AND WATER HEATER HAVING SAME

Non-Final OA §103
Filed
Aug 29, 2023
Examiner
GIORDANO, MICHAEL JAMES
Art Unit
3762
Tech Center
3700 — Mechanical Engineering & Manufacturing
Assignee
Wuhu Midea Kitchen And Bath Appliances Mfg Co. Ltd.
OA Round
1 (Non-Final)
79%
Grant Probability
Favorable
1-2
OA Rounds
2y 10m
To Grant
99%
With Interview

Examiner Intelligence

Grants 79% — above average
79%
Career Allow Rate
153 granted / 193 resolved
+9.3% vs TC avg
Strong +21% interview lift
Without
With
+20.7%
Interview Lift
resolved cases with interview
Typical timeline
2y 10m
Avg Prosecution
37 currently pending
Career history
230
Total Applications
across all art units

Statute-Specific Performance

§101
0.1%
-39.9% vs TC avg
§103
61.1%
+21.1% vs TC avg
§102
24.4%
-15.6% vs TC avg
§112
11.3%
-28.7% vs TC avg
Black line = Tech Center average estimate • Based on career data from 193 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. Claim(s) 1-9 and 12-20 is/are rejected under 35 U.S.C. 103 as being unpatentable over Liu (CN 210485713 U) in view of Schmidt (DE 102012009628 A1). Regarding claim 1, Liu teaches of: A premixing device for a water heater, the premixing device comprising: a housing (Fig. 1, 100 has a housing 10), in which a first airflow passage (Fig. 9, 1121), a second airflow passage (Fig. 9, 1122), a first gas passage (Fig. 9, 1111), and a second gas passage are formed (Fig. 9, 1112); and a turning plate rotatably disposed on the housing to adjust an opening degree of the first gas passage and an opening degree of the first airflow passage (Fig. 6, 20; ¶ [0059], Thus, valve 20 can control the amount of gas and air entering the gas flow channel 11 by adjusting the normally closed gas flow channel 1111 and/or the normally closed air flow channel 1121) Liu fails to explicitly teach: an air guide hole directly opposite to the first airflow passage being formed on the turning plate. Schmidt teaches of: an air guide hole directly opposite to the first airflow passage being formed on the turning plate (Fig. 4, 9 has air guide holes 13) The primary reference can be modified to meet this/these limitation(s) as follows: add an air guide hole to the turning plate 20 of Liu positioned in a way so that when 20 is closed air can still flow through the air guide hole from the first flow channel 1121 A person of ordinary skill in the art prior to the effective filing date of the claimed invention would have been motivated to make the above modification(s) because: Since the change in flow rate of air to the amount of fuel pulled into the venturi due to a pressure difference is not 1:1, at low combustion levels where the turning plate is closed so that both the first air and gas channels are closed and the second air and gas channels are opened the air-gas ratio drops so that the mixture is rich in gas. Therefore, by adding the air guide holes to the turning plate some air can still flow through the turning plate via the air guide holes, maintaining an oxygen rich combustion gas mixture and resulting in reduced NOx formation (Schmidt, Fig. 5, the Y-axis represents air-gas ratio, a higher number means more air compared to gas, the X-axis represented the power output of the burner, line 15 represents a valve with no air guide holes, at low power levels there is a drop in the ratio resulting in an increase in pollutant formation, line 16 represents the valve of Fig. 4 with air guide holes, at low power levels the drop in the ratio is reduced and therefore pollutant formation is reduced) Regarding claim 2, the combined teachings teach of the premixing device for the water heater according to claim 1, and the combined teachings further teach: wherein the first gas passage is surrounded by the first airflow passage (Liu, Fig. 12, 1121 surrounds 1111) Regarding claim 3, the combined teachings teach of the premixing device for the water heater according to claim 2, and the combined teachings further teach: wherein: a first support portion is disposed in the housing, the first airflow passage being formed in the first support portion; and a second support portion is disposed in the first airflow passage, the first gas passage being formed in the second support portion (See annotated Fig. 11 of Liu below, the first airflow passage 1121 has a first support portion and within the first airflow passage is the second support portion which has the first gas passage 1111 within it). Regarding claim 4, the combined teachings teach of the premixing device for the water heater according to claim 3, and the combined teachings further teach: wherein: an end surface of a free end of the second support portion and an end surface of a free end of the first support portion are disposed obliquely (see annotated Fig. 6 of Liu below, the free end of the first and second support portions are disposed obliquely); and the turning plate is rotatable to abut against the end surface of the second support portion and/or the end surface of the first support portion (see annotated Fig. 6 of Liu below, the turning plate 20 abuts the end supports of the first and second support portions). Regarding claim 5, the combined teachings teach of the premixing device for the water heater according to claim 4, and the combined teachings further teach: wherein the first support portion is inclined in an air flow direction from top to bottom (See both annotated Fig. 6 and 11 of Liu below, the first support portion is inclined from top to bottom in an airflow direction) Regarding claim 6, the combined teachings teach of the premixing device for the water heater according to claim 4, and the combined teachings further teach: wherein: a third support portion is disposed in the housing, a second airflow passage being formed in the third support portion (see annotated Fig. 11 of Liu below, a second airflow passage 1122 is within the third support portion); a fourth support portion is disposed in the second airflow passage, a second gas passage being formed in the fourth support portion (see annotated Fig. 11 of Liu below, the fourth support portion is within the second airflow passage 1122 and the second gas passage 1112 is within the fourth support portion); and an end surface of the third support portion protrudes relative to the end surface of the first support portion (see annotated Fig. 11 of Liu below, the third support portion protrudes relative to the first support portion). Regarding claim 7, the combined teachings teach of the premixing device for the water heater according to claim 6, and the combined teachings further teach: wherein: a first support rib is disposed between the first support portion and the second support portion; and a second support rib is disposed between the third support portion and the fourth support portion (See annotated Fig. 11 of Liu below). Regarding claim 8, the combined teachings teach of the premixing device according to claim 5, and the combined teachings further teach: wherein: a third support portion is disposed in the housing, a second airflow passage being formed in the third support portion; a fourth support portion is disposed in the second airflow passage, a second gas passage being formed in the fourth support portion; and an end surface of the third support portion protrudes relative to the end surface of the first support portion (see rejection of claim 6 above and annotated Fig. 11 of Liu below, the housing as a third and fourth support portions, the fourth support portion is within the third support portion and the second airflow and gas passages are within the support portions) Regarding claim 9, the combined teachings teach of the premixing device according to claim 8, and the combined teachings further teach: wherein: a first support rib is disposed between the first support portion and the second support portion; and a second support rib is disposed between the third support portion and the fourth support portion (See rejection of claim 7 above and annotated Fig. 11 of Liu below, there is a first support rib disposed between the first and second support portions and a third support rib disposed between the third and fourth support portions) Regarding claim 12, Liu teaches of: A water heater, comprising a premixing device (¶ [0002], This utility model relates to the field of water heater technology, and more specifically, to a Venturi device and a gas appliance), the premixing device comprising: a housing (Fig. 1, 100 has a housing 10), in which a first airflow passage (Fig. 9, 1121), a second airflow passage (Fig. 9, 1122), a first gas passage (Fig. 9, 1111), and a second gas passage are formed (Fig. 9, 1112); and a turning plate rotatably disposed on the housing to adjust an opening degree of the first gas passage and an opening degree of the first airflow passage (Fig. 6, 20; ¶ [0059], Thus, valve 20 can control the amount of gas and air entering the gas flow channel 11 by adjusting the normally closed gas flow channel 1111 and/or the normally closed air flow channel 1121) Liu fails to explicitly teach: an air guide hole directly opposite to the first airflow passage being formed on the turning plate. Schmidt teaches of: an air guide hole directly opposite to the first airflow passage being formed on the turning plate (Fig. 4, 9 has air guide holes 13) The primary reference can be modified to meet this/these limitation(s) as follows: add an air guide hole to the turning plate 20 of Liu positioned in a way so that when 20 is closed air can still flow through the air guide hole from the first flow channel 1121 A person of ordinary skill in the art prior to the effective filing date of the claimed invention would have been motivated to make the above modification(s) because: Since the change in flow rate of air to the amount of fuel pulled into the venturi due to a pressure difference is not 1:1, at low combustion levels where the turning plate is closed so that both the first air and gas channels are closed and the second air and gas channels are opened the air-gas ratio drops so that the mixture is rich in gas. Therefore, by adding the air guide holes to the turning plate some air can still flow through the turning plate via the air guide holes, maintaining an oxygen rich combustion gas mixture and resulting in reduced NOx formation (Schmidt, Fig. 5, the Y-axis represents air-gas ratio, a higher number means more air compared to gas, the X-axis represented the power output of the burner, line 15 represents a valve with no air guide holes, at low power levels there is a drop in the ratio resulting in an increase in pollutant formation, line 16 represents the valve of Fig. 4 with air guide holes, at low power levels the drop in the ratio is reduced and therefore pollutant formation is reduced) Regarding claim 13, the combined teachings teach of the water heater according to claim 12, and the combined teachings further teach: wherein the first gas passage is surrounded by the first airflow passage (Liu, Fig. 12, 1121 surrounds 1111) Regarding claim 14, the combined teachings teach of the water heater according to claim 13, and the combined teachings further teach: wherein: a first support portion is disposed in the housing, the first airflow passage being formed in the first support portion; and a second support portion is disposed in the first airflow passage, the first gas passage being formed in the second support portion (See annotated Fig. 11 of Liu below, the first airflow passage 1121 has a first support portion and within the first airflow passage is the second support portion which has the first gas passage 1111 within it). Regarding claim 15, the combined teachings teach of the water heater according to claim 14, and the combined teachings further teach: wherein: an end surface of a free end of the second support portion and an end surface of a free end of the first support portion are disposed obliquely (see annotated Fig. 6 of Liu below, the free end of the first and second support portions are disposed obliquely); and the turning plate is rotatable to abut against the end surface of the second support portion and/or the end surface of the first support portion (see annotated Fig. 6 of Liu below, the turning plate 20 abuts the end supports of the first and second support portions). Regarding claim 16, the combined teachings teach of the water heater according to claim 15, and the combined teachings further teach: wherein the first support portion is inclined in an air flow direction from top to bottom (See both annotated Fig. 6 and 11 of Liu below, the first support portion is inclined from top to bottom in an airflow direction) Regarding claim 17, the combined teachings teach of the water heater according to claim 15, and the combined teachings further teach: wherein: a third support portion is disposed in the housing, a second airflow passage being formed in the third support portion (see annotated Fig. 11 of Liu below, a second airflow passage 1122 is within the third support portion); a fourth support portion is disposed in the second airflow passage, a second gas passage being formed in the fourth support portion (see annotated Fig. 11 of Liu below, the fourth support portion is within the second airflow passage 1122 and the second gas passage 1112 is within the fourth support portion); and an end surface of the third support portion protrudes relative to the end surface of the first support portion (see annotated Fig. 11 of Liu below, the third support portion protrudes relative to the first support portion). Regarding claim 18, the combined teachings teach of the water heater according to claim 17, and the combined teachings further teach: wherein: a first support rib is disposed between the first support portion and the second support portion; and a second support rib is disposed between the third support portion and the fourth support portion (See annotated Fig. 11 of Liu below). Regarding claim 19, the combined teachings teach of the water heater according to claim 16, and the combined teachings further teach: wherein: a third support portion is disposed in the housing, a second airflow passage being formed in the third support portion; a fourth support portion is disposed in the second airflow passage, a second gas passage being formed in the fourth support portion; and an end surface of the third support portion protrudes relative to the end surface of the first support portion (see rejection of claim 17 above and annotated Fig. 11 of Liu below, the housing as a third and fourth support portions, the fourth support portion is within the third support portion and the second airflow and gas passages are within the support portions) Regarding claim 20, the combined teachings teach of the water heater according to claim 16, and the combined teachings further teach: wherein: a first support rib is disposed between the first support portion and the second support portion; and a second support rib is disposed between the third support portion and the fourth support portion (See rejection of claim 18 above and annotated Fig. 11 of Liu below, there is a first support rib disposed between the first and second support portions and a third support rib disposed between the third and fourth support portions) Claim(s) 1 and 10-11 is/are rejected under 35 U.S.C. 103 as being unpatentable over Kanazawa (US 20190346133 A1) in view of Schmidt (DE 102012009628 A1). Regarding claim 1, Kanazawa teaches of: A premixing device for a water heater, the premixing device comprising: a housing (Figs. 7A-B, 40), in which a first airflow passage (Figs. 7A-B, 54 a second airflow passage (Figs. 7A-B, 53), a first gas passage (Figs. 7A-B, 64), and a second gas passage are formed (Figs. 7A-B, 63); and a turning plate rotatably disposed on the housing to adjust an opening degree of the first gas passage and an opening degree of the first airflow passage (Figs. 7B-8B, 55 controls the opening degree of 54 and 64) Kanazawa fails to explicitly teach: an air guide hole directly opposite to the first airflow passage being formed on the turning plate. Schmidt teaches of: an air guide hole directly opposite to the first airflow passage being formed on the turning plate (Fig. 4, 9 has air guide holes 13) The primary reference can be modified to meet this/these limitation(s) as follows: add an air guide hole to the turning plate 55 of Kanazawa positioned in a way so that when 55 is closed air can still flow through the air guide hole from the first flow channel 54 A person of ordinary skill in the art prior to the effective filing date of the claimed invention would have been motivated to make the above modification(s) because: At low combustion levels where the turning plate is closed so that both the first air and gas channels are closed and the second air and gas channels are opened, some air can still flow through the turning plate via the air guide holes, maintaining an oxygen rich combustion gas mixture and resulting in reduced NOx formation (Schmidt, Fig. 5, the Y-axis represents air-gas ratio, a higher number means more air compared to gas, the X-axis represented the power output of the burner, line 15 represents a valve with no air guide holes, at low power levels there is a drop in the ratio resulting in an increase in pollutant formation, line 16 represents the valve of Fig. 4 with air guide holes, at low power levels the drop in the ratio is reduced and therefore pollutant formation is reduced) Regarding claim 10, the combined teachings teach of the premixing device according to claim 1, and the combined teachings further teach: further comprising a deflector rib directly opposite to the first gas passage, wherein the deflector rib is disposed on the turning plate (see annotated Fig. 7B of Kanazawa below, deflector rib on 55 is disposed directly opposite of 64) Regarding claim 11, the combined teachings teach of the premixing device according to claim 1, and the combined teachings further teach: wherein a sectional area of the second gas passage is smaller than a sectional area of the first gas passage (Kanazawa, Fig. 7A, 63 has a smaller area than 64) Annotated Figures PNG media_image1.png 742 1201 media_image1.png Greyscale Annotated Fig. 6 of Liu PNG media_image2.png 656 1100 media_image2.png Greyscale Annotated Fig. 11 of Liu PNG media_image3.png 526 528 media_image3.png Greyscale Annotated Fig. 7B of Kanazawa Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to MICHAEL J GIORDANO whose telephone number is (571)272-8940. The examiner can normally be reached M-Fr 8 AM - 5 PM EST. 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, Steve McAllister can be reached at (571) 272-6785. 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. /MICHAEL JAMES GIORDANO/Examiner, Art Unit 3762 /STEVEN B MCALLISTER/Supervisory Patent Examiner, Art Unit 3762
Read full office action

Prosecution Timeline

Aug 29, 2023
Application Filed
Jan 30, 2026
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

1-2
Expected OA Rounds
79%
Grant Probability
99%
With Interview (+20.7%)
2y 10m
Median Time to Grant
Low
PTA Risk
Based on 193 resolved cases by this examiner. Grant probability derived from career allow rate.

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