IP Library › Granted Patent US 12,320,550
Granted Patent B2
US 12,320,550 · App. 16/973,016 · Granted Jun 3, 2025

Heat-exchange pipe, heat-exchanger unit using same, and condensing boiler using same

Inventors: Jun Kyu Park (Seoul, KR); Jun Gil Park (Seoul, KR)
Assignee: KYUNGDONG NAVIEN CO., LTD.
F24H8/00F24H1/0036F24H8/006F28D21/0007F28D2021/0024F28F1/325F28F13/08F28F2210/08
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Quick Facts
Patent No.
US 12,320,550
App. No.
16/973,016
Granted
Jun 3, 2025
Kind
B2
Abstract

A heat-exchanger unit according to the present invention comprises: a sensible-heat heat-exchange portion arranged in a sensible-heat heat-exchange area for receiving sensible heat generated by a combustion reaction and thereby heating water, the sensible-heat heat-exchange portion having a sensible-heat heat-exchange pipe for receiving the water and causing same to flow through the interior thereof, thereby forming a sensible-heat channel along which the water flows; and a latent-heat heat-exchange portion positioned downstream of the sensible-heat heat-exchange area with reference to a first reference direction along which combustion gas generated during the combustion reaction flows, the latent-heat heat-exchange portion being arranged in a latent-heat heat-exchange area for receiving latent heat generated during a phase change of the combustion gas and thereby heating the water, the latent-heat heat-exchange portion having a latent-heat heat-exchange pipe for receiving the water and causing same to flow through the interior thereof.

Claims (57)

1. A heat exchanger unit comprising:

a sensible heat exchanging part disposed in a sensible heat exchange area configured to receive sensible heat generated by a combustion reaction and to heat water, the sensible heat exchanging part including a sensible heat exchange pipe configured to receive the water and allow the water to flow therethrough to form a sensible heat flow passage through which the water flows; and

a latent heat exchanging part disposed in a latent heat exchange area, the latent heat exchanging part including a latent heat exchange pipe configured to receive the water and allow the water to flow therethrough, wherein the latent heat exchange area is located downstream of the sensible heat exchange area based on a first reference direction that is a flow direction of combustion gas generated during the combustion reaction, the latent heat exchange area being configured to receive latent heat generated during a phase change of the combustion gas and to heat the water, and

a housing configured to surround the heat exchange areas to define the heat exchange areas therein,

wherein the latent heat exchange pipe includes a plurality of latent heat straight portions extending along a second reference direction perpendicular to the first reference direction, the plurality of latent heat straight portions being arranged to be spaced apart from each other along a third reference direction perpendicular to the first reference direction and the second reference direction and configured to form a latent heat flow passage through which the water flows and that is connected to the sensible heat flow passage,

wherein interior spaces of the sensible heat straight portions and the latent heat straight portions are formed to be long and narrow such that widths in the third reference direction are smaller than lengths in the first reference direction,

wherein the latent heat exchange pipe includes a plurality of upstream straight portions and a plurality of downstream straight portions located downstream of the upstream straight portions based on the first reference direction,

wherein the heat exchanger unit further comprises:

a sensible heat fin coupled with the sensible heat exchange pipe;

an upstream fin coupled to the upstream straight portions and arranged to be spaced apart from the sensible heat fin along the first reference direction; and

a downstream fin coupled to the downstream straight portions and arranged to be spaced apart from the upstream fin along the first reference direction,

wherein cross-sectional areas of the heat exchange areas defined on a plane perpendicular to the first reference direction are referred to as reference cross-sectional areas,

wherein most upstream side of each fin based on the first reference direction are referred to as an inlet end and the most downstream side of each fin based on the first reference direction are referred to as an outlet end and,

wherein the housing is provided such that the reference cross-sectional area decreases from the outlet end of the sensible heat fin to the inlet end of the upstream fin, and

wherein the housing is provided such that the reference cross-sectional area decreases from the outlet end of the upstream fin to the inlet end of the downstream fin along the first reference direction, and

wherein the housing is provided such that the reference cross-sectional area defined at the outlet end of the downstream fin is smaller than the reference cross-sectional area defined at the inlet end of the upstream fin.

2. The heat exchanger unit of claim 1 , wherein in cross-sections obtained by cutting the straight portions with a plane perpendicular to the second reference direction, perimeters of the straight portions are referred to as external dimensions of the straight portions,

wherein in the cross-sections obtained by cutting the straight portions with the plane perpendicular to the second reference direction, external dimensions of the straight portions from the most upstream sides of the straight portions to separation points of the combustion gas for the straight portions based on the first reference direction are referred to as contact lengths,

wherein values obtained by dividing the contact lengths of the latent heat straight portions by the external dimensions of the latent heat straight portions are greater than values obtained by dividing the contact lengths of the sensible heat straight portions by the external dimensions of the sensible heat straight portions, and

wherein the separation points are points at which a rate of change of speed of the combustion gas along the third reference direction on surfaces of the straight portions is 0.

3. The heat exchanger unit of claim 1 , wherein for the interior spaces of the latent heat straight portions, values obtained by dividing the widths in the third reference direction by the lengths in the first reference direction are referred to as aspect ratios, and

wherein the aspect ratios of the latent heat straight portions range from 0.05 to 0.3.

4. The heat exchanger unit of claim 1 ,

wherein the housing is provided such that based on the first reference direction, a reference cross-sectional area at the most downstream side is smaller than a reference cross-sectional area at the most upstream side.

5. The heat exchanger unit of claim 4 , wherein the plurality of latent heat straight portions form a plurality of rows,

wherein each row includes the latent heat straight portions located in the same position based on the first reference direction.

6. The heat exchanger unit of claim 1 , wherein the latent heat flow passage includes a parallel flow passage in at least a partial section.

7. The heat exchanger unit of claim 1 , wherein the sensible heat exchange pipe includes a plurality of sensible heat straight portions extending along the second reference direction, the plurality of sensible heat straight portions being arranged to be spaced apart from each other along the third direction and configured to form the sensible heat flow passage through which the water flows.

8. The heat exchanger unit of claim 7 , wherein for interior spaces of the straight portions, values obtained by dividing widths in the third reference direction by lengths in the first reference direction are referred to as aspect ratios, and

wherein the aspect ratios of the latent heat straight portions are smaller than the aspect ratios of the sensible heat straight portions.

9. The heat exchanger unit of claim 7 , wherein in cross-sections obtained by cutting the straight portions with a plane perpendicular to the second reference direction, perimeters of interior spaces of the straight portions are referred to as internal dimensions of the straight portions, and

wherein the internal dimensions of the latent heat straight portions are smaller than the internal dimensions of the sensible heat straight portions.

10. The heat exchanger unit of claim 7 , wherein in cross-sections obtained by cutting the straight portions with a plane perpendicular to the second reference direction, perimeters of interior spaces of the straight portions are referred to as internal dimensions of the straight portions,

wherein in the cross-sections obtained by cutting the straight portions with the plane perpendicular to the second reference direction, internal upstream portions and internal downstream portions adjacent to the most upstream sides and the most downstream sides of the interior spaces of the straight portions based on the first reference direction are formed in a shape of at least part of a sector having a predetermined radius of curvature, and pairs of internal lateral portions that are opposite sides of the interior spaces of the straight portions based on the third reference direction are formed in a shape of at least part of a sector having a radius of curvature different from the predetermined radius of curvature,

wherein in the cross-sections, lengths from the most upstream sides of the internal upstream portions to places where the internal downstream portions and the internal lateral portions meet based on the first reference direction are referred to as effective heat transfer lengths, and

wherein values obtained by dividing the effective heat transfer lengths of the latent heat straight portions by the internal dimensions of the latent heat straight portions are greater than values obtained by dividing the effective heat transfer lengths of the sensible heat straight portions by the internal dimensions of the sensible heat straight portions.

11. The heat exchanger unit of claim 10 , wherein the internal lateral portions of the latent heat straight portions have an infinite radius of curvature.

12. A condensing boiler comprising:

a burner assembly configured to cause a combustion reaction;

a combustion chamber located downstream of the burner assembly based on a first reference direction that is a flow direction of combustion gas generated during the combustion reaction, flame by the combustion reaction being located in the combustion chamber; and

a heat exchanger unit configured to receive sensible heat generated by the combustion reaction and the combustion gas and to heat water,

wherein the heat exchanger unit includes:

a sensible heat exchanging part disposed in a sensible heat exchange area configured to receive the sensible heat generated by the combustion reaction and to heat the water, the sensible heat exchanging part including a sensible heat exchange pipe configured to receive the water and allow the water to flow therethrough;

a latent heat exchanging part disposed in a latent heat exchange area, the latent heat exchanging part including a latent heat exchange pipe configured to receive the water and allow the water to flow therethrough, wherein the latent heat exchange area is located downstream of the sensible heat exchange area based on the first reference direction and is configured to receive latent heat generated during a phase change of the combustion gas and to heat the water; and

a housing configured to surround the heat exchange areas to define the heat exchange areas therein,

wherein the latent heat exchange pipe includes a plurality of latent heat straight portions extending along a second reference direction perpendicular to the first reference direction, the plurality of latent heat straight portions being arranged to be spaced apart from each other along a third reference direction perpendicular to the first reference direction and the second reference direction and configured to form a latent heat flow passage through which the water flows and that is connected to the sensible heat exchange pipe,

wherein interior spaces of the sensible heat straight portions and the latent heat straight portions are formed to be long and narrow such that widths in the third reference direction are smaller than lengths in the first reference direction,

wherein the latent heat exchange pipe includes a plurality of upstream straight portions and a plurality of downstream straight portions located downstream of the upstream straight portions based on the first reference direction,

wherein the heat exchanger unit further comprises:

a sensible heat fin coupled with the sensible heat exchange pipe;

an upstream fin coupled to the upstream straight portions and arranged to be spaced apart from the sensible heat fin along the first reference direction; and

a downstream fin coupled to the downstream straight portions and arranged to be spaced apart from the upstream fin along the first reference direction,

wherein cross-sectional areas of the heat exchange areas defined on a plane perpendicular to the first reference direction are referred to as reference cross-sectional areas,

wherein most upstream side of each fin based on the first reference direction are referred to as an inlet end and the most downstream side of each fin based on the first reference direction are referred to as an outlet end and,

wherein the housing is provided such that the reference cross-sectional area decreases from the outlet end of the sensible heat fin to the inlet end of the upstream fin, and

wherein the housing is provided such that the reference cross-sectional area decreases from the outlet end of the upstream fin to the inlet end of the downstream fin along the first reference direction, and

wherein the housing is provided such that the reference cross-sectional area defined at the outlet end of the downstream fin is smaller than the reference cross-sectional area defined at the inlet end of the upstream fin.

Assignments (1)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Jan 20, 2021
From: PARK, JUN KYU; PARK, JUN GIL
To: KYUNGDONG NAVIEN CO.,LTD.
Reel/Frame 055039/0396 →
Priority Claims (5)
KR 10-2018-0064666 · Jun 5, 2018 · national
KR 10-2018-0064668 · Jun 5, 2018 · national
KR 10-2018-0064669 · Jun 5, 2018 · national
KR 10-2018-0172605 · Dec 28, 2018 · national
KR 10-2019-0062723 · May 28, 2019 · national
Continuity (1)
Related Publication 20210247102A1 · Aug 12, 2021
References Cited (176)
US 2006649A · Modine · 1935 [cited by examiner]
US 4509672A · Woodhull, Jr. et al. · 1985 [cited by applicant]
US 5346001A · Rieke · 1994 [cited by examiner]
US 5359989A · Chase · 1994 [cited by examiner]
US 5437248A · Miura et al. · 1995 [cited by applicant]
US 5761808A · Patel et al. · 1998 [cited by applicant]
US 6059174A · Kojima et al. · 2000 [cited by applicant]
US 6923013B2 · Chiang · 2005 [cited by examiner]
US 7096933B1 · Zia · 2006 [cited by examiner]
US 7353781B2 · Jung · 2008 [cited by applicant]
US 10126014B2 · Kim · 2018 [cited by applicant]
US 10254053B2 · Okamoto et al. · 2019 [cited by applicant]
US 10295222B2 · Ooshita · 2019 [cited by applicant]
US 10393404B2 · Kondo et al. · 2019 [cited by applicant]
US 10408549B2 · Oohigashi et al. · 2019 [cited by applicant]
US 10605484B2 · Kim · 2020 [cited by applicant]
US 10612776B2 · Ono et al. · 2020 [cited by applicant]
US 10823455B2 · Park et al. · 2020 [cited by applicant]
US 10890356B2 · Shiotsu et al. · 2021 [cited by applicant]
US 10928063B2 · Ono et al. · 2021 [cited by applicant]
US 11287158B2 · Kondo et al. · 2022 [cited by applicant]
US 20040031480A1 · Jung · 2004 [cited by applicant]
US 20070204980A1 · Kim et al. · 2007 [cited by applicant]
US 20100116226A1 · Lovascio · 2010 [cited by applicant]
US 20100307727A1 · Min · 2010 [cited by applicant]
US 20110114300A1 · Kim et al. · 2011 [cited by applicant]
US 20130125838A1 · Min · 2013 [cited by applicant]
US 20130180689A1 · Boening · 2013 [cited by applicant]
US 20130216962A1 · Dresner · 2013 [cited by applicant]
US 20150204579A1 · Brown et al. · 2015 [cited by applicant]
US 20150300687A1 · Cui · 2015 [cited by applicant]
US 20160273850A1 · Okamoto et al. · 2016 [cited by applicant]
US 20160377320A1 · Kim · 2016 [cited by applicant]
US 20170059205A1 · Kim · 2017 [cited by applicant]
US 20170108281A1 · Klaves et al. · 2017 [cited by applicant]
US 20170335740A1 · Dries et al. · 2017 [cited by applicant]
US 20180087805A1 · Ooshita · 2018 [cited by applicant]
US 20180087806A1 · Kondo et al. · 2018 [cited by applicant]
US 20180216848A1 · Jeong · 2018 [cited by applicant]
US 20180238639A1 · Jeong · 2018 [cited by applicant]
US 20180363897A1 · Ono et al. · 2018 [cited by applicant]
US 20180363948A1 · Park · 2018 [cited by applicant]
US 20180372311A1 · Ono et al. · 2018 [cited by applicant]
US 20190154300A1 · Kondo et al. · 2019 [cited by applicant]
US 20190226719A1 · Shiotsu et al. · 2019 [cited by applicant]
US 20210199340A1 · Park et al. · 2021 [cited by applicant]
US 20210247103A1 · Park et al. · 2021 [cited by applicant]
AT 396026B · 1993 [cited by applicant]
AT 399772B · 1995 [cited by applicant]
CA 2978765A2 · 2018 [cited by applicant]
CN 1370964A · 2002 [cited by applicant]
CN 1460820A · 2003 [cited by applicant]
CN 1605812A · 2005 [cited by applicant]
CN 2842210 · 2006 [cited by applicant]
CN 101782270A · 2010 [cited by applicant]
CN 101903711A · 2010 [cited by applicant]
CN 102901221 · 2013 [cited by applicant]
CN 103069225A · 2013 [cited by applicant]
CN 205299948U · 2016 [cited by applicant]
CN 105987632A · 2016 [cited by applicant]
CN 106133456A · 2016 [cited by applicant]
CN 205690651U · 2016 [cited by applicant]
CN 206478864U · 2017 [cited by applicant]
CN 107923653A · 2018 [cited by applicant]
DE 102017212965B4 · 2020 [cited by applicant]
EP 0195383A2 · 1986 [cited by applicant]
EP 0685698A · 1995 [cited by applicant]
EP 0687870B1 · 2000 [cited by applicant]
EP 1026454A2 · 2000 [cited by applicant]
EP 1139036A2 · 2001 [cited by applicant]
EP 1396688A2 · 2004 [cited by examiner]
EP 1026454B1 · 2006 [cited by applicant]
EP 2722610A1 · 2014 [cited by examiner]
EP 3173722 · 2017 [cited by applicant]
FR 2640028A2 · 1990 [cited by applicant]
JP S60106058U · 1985 [cited by applicant]
JP 2003021390A · 2003 [cited by applicant]
JP 2003161527A · 2003 [cited by applicant]
JP 2005326102A · 2005 [cited by applicant]
JP 2006153375 · 2006 [cited by applicant]
JP 2006284037A · 2006 [cited by applicant]
JP 2019095116A · 2019 [cited by applicant]
JP 2019128083A · 2019 [cited by applicant]
KR 1019990000646A · 1999 [cited by applicant]
KR 2019990000409U · 1999 [cited by applicant]
KR 100219911B1 · 1999 [cited by applicant]
KR 1020000057855A · 2000 [cited by applicant]
KR 200219877Y · 2001 [cited by applicant]
KR 1020010049983A · 2001 [cited by applicant]
KR 200257930Y · 2001 [cited by applicant]
KR 1020020000703A · 2002 [cited by applicant]
KR 1020020001465A · 2002 [cited by applicant]
KR 20020067301A · 2002 [cited by applicant]
KR 100361553B · 2002 [cited by applicant]
KR 100386960B · 2003 [cited by applicant]
KR 100392593B · 2003 [cited by applicant]
KR 1020050000127A · 2005 [cited by applicant]
KR 1020060000590A · 2006 [cited by applicant]
KR 100570286B1 · 2006 [cited by applicant]
KR 100570291B1 · 2006 [cited by applicant]
KR 1020090047901A · 2009 [cited by applicant]
KR 1020180007933A · 2009 [cited by applicant]
KR 1020090067760A · 2009 [cited by applicant]
KR 100933419B · 2009 [cited by applicant]
KR 1020100054384A · 2010 [cited by applicant]
KR 100975104B · 2010 [cited by applicant]
KR 1020100117842A · 2010 [cited by applicant]
KR 1020100128505A · 2010 [cited by applicant]
KR 1020110077307A · 2011 [cited by applicant]
KR 100896407B · 2011 [cited by applicant]
KR 1020140051760A · 2014 [cited by applicant]
KR 20140083626A · 2014 [cited by examiner]
KR 1020140083626A · 2014 [cited by applicant]
KR 101445786B · 2014 [cited by applicant]
KR 101586646B · 2016 [cited by applicant]
KR 1020170025476 · 2017 [cited by applicant]
KR 1020110077308A · 2017 [cited by applicant]
KR 1020170067491A · 2017 [cited by applicant]
KR 2020170003855U · 2017 [cited by applicant]
KR 101810122B1 · 2017 [cited by applicant]
KR 1020180007984A · 2018 [cited by applicant]
KR 1020170031338A · 2018 [cited by applicant]
KR 1020180087986A · 2018 [cited by applicant]
KR 1020180097681A · 2018 [cited by applicant]
KR 1020180097682A · 2018 [cited by applicant]
KR 1020210032348A · 2018 [cited by applicant]
KR 1020190132043A · 2019 [cited by applicant]
KR 1020190138553A · 2019 [cited by applicant]
KR 1020190138554A · 2019 [cited by applicant]
KR 1020190138555A · 2019 [cited by applicant]
KR 1020210032347A · 2021 [cited by applicant]
KR 1020210039363A · 2021 [cited by applicant]
WO 2006097959A1 · 2006 [cited by applicant]
WO 2007102653A1 · 2007 [cited by applicant]
WO 2008056238A2 · 2008 [cited by applicant]
WO 2012020909A · 2012 [cited by applicant]
WO 2012177154A · 2012 [cited by applicant]
WO 2014104575A · 2014 [cited by applicant]
WO 2017099381A · 2017 [cited by applicant]
First Office Action for related Chinese Patent Application No. 201980037912.7 dated Nov. 1, 2021, 9 pages long. [cited by applicant]
Notice of Allowance for related Korean Patent Application No. 10-2018-0156357 received on Nov. 17, 2021, 2 pages long. [cited by applicant]
First Office Action for corresponding Chinese Patent Application No. 201980038009.2 received on Nov. 16, 2021, 10 pages long. [cited by applicant]
Extended European Search Report for related EP Application No. 20217737.4 dated May 11, 2021, 8 pages long. [cited by applicant]
Notice of Reason for Cancellation for related Korean Patent Application No. 10-2019-0178390 dated Jan. 17, 2022, 2 pages long. [cited by applicant]
Notice of Reason for Cancellation for related Korean Patent Application No. 10-2019-0178390 dated Mar. 31, 2022, 2 pages long. [cited by applicant]
“Report On Development Of Multi-Stage Core Type Oil Cooling Systems For Marine And Industrial Use” (Final Version) issued on Jun. 2005, pp. 11, 12 and 34. [cited by applicant]
Office Action dated Jan. 14, 2022, for related U.S. Appl. No. 16/973,025 (pp. 1-5). [cited by applicant]
Office Action for related Chinese Patent Application No. 202011606440.3, dated May 30, 2022, 21 pages. [cited by applicant]
Office Action for related Korean Patent Application No. 10-2020-0083879, dated Jun. 14, 2022, 9 pages. [cited by applicant]
Office Action for related U.S. Appl. No. 16/973,025, dated Jul. 7, 2022, 19 pages. [cited by applicant]
International Search Report and Written Opinion for International Patent Application No. PCT/KR2019/006542 dated Aug. 29, 2019, 10 pages long. [cited by applicant]
Notification of Third Party Submission for related Korean Patent Application No. 10-2021-0032298 dated Dec. 29, 2021, 2 pages long. [cited by applicant]
Notification of Third Party Submission for related Korean Patent Application No. 10-2021-0032298 dated Feb. 10, 2022, 2 pages long. [cited by applicant]
Notice of Reason for Cancellation for related Korean Patent Application No. 10-2018-0156356 dated Feb. 24, 2022, 13 pages long. [cited by applicant]
Extended European Search Report for European Application No. 19814828.0 dated Jun. 9, 2021, 7 pages long. [cited by applicant]
First Office Action for Korean Patent Application No. 10-2021-0032298 dated Jun. 18, 2021, 6 pages long. [cited by applicant]
First Office Action for Korean Patent Application No. 10-2021-0039671 dated Jun. 18, 2021, 6 pages long. [cited by applicant]
Extended European Search Report for European Application No. 19814468.5 dated Jul. 5, 2021, 9 pages long. [cited by applicant]
Office Action for related U.S. Appl. No. 17/131,772, dated Sep. 22, 2022, 50 pages. [cited by applicant]
Office Action for related Korean Patent Application No. 10-2022-0119550, dated Nov. 30, 2022, 8 pages. [cited by applicant]
Development of Ultra-Efficient Green Condensing Gas Boiler, pp. 1-160, publication date: May of 2013, publisher: Kiturami Co. Ltd., place of publication: https://www.ntis.go.kr/outcomes/popup/srchTotIRschRpt.do?cmd=get_… [cited by applicant]
Concise Description of Relevance of Prior Art, filed with USPTO for U.S. Appl. No. 17/709,444, filed Dec. 14, 2022. [cited by applicant]
Concise Description of Relevance of Prior Art, filed with USPTO for U.S. Appl. No. 17/709,450, filed Dec. 14, 2022. [cited by applicant]
Concise Description of Relevance of Prior Art, filed with USPTO for U.S. Appl. No. 17/709,568, filed Dec. 14, 2022. [cited by applicant]
Chinese Office Action dated Mar. 27, 2023, in related Chinese Patent Application No. 202210757708.6; 9 pages. [cited by applicant]
Chinese Office Action dated Mar. 27, 2023, in related Chinese Patent Application No. 202210759593.4; 9 pages. [cited by applicant]
US Final Office Action dated Mar. 30, 2023, in related U.S. Appl. No. 17/131,772; 23 pages. [cited by applicant]
Korean Patent Office, Notification of First Office Action for corresponding Application No. 10-2023-0064904 report issue date Jun. 29, 2023, Korea, 6 pages. [cited by applicant]
Korean Patent Office, Notification of First Office Action for corresponding Application No. 10-2023-0108464 report issue date Sep. 15, 2023, Korea, 7 pages. [cited by applicant]
Korean Patent Office, Notification of Preliminary Rejection for corresponding Application No. 10-2022-0119550 report issue date Sep. 15, 2023, Korea, 5 pages. [cited by applicant]
Chinese Patent Office, Notice of Allowance for corresponding Application No. 202210759593.4 report issue date Sep. 28, 2023, Korea, 5 pages. [cited by applicant]
Korean Patent Office, Notice of First Office Action for related Korean patent application No. 10-2024-0040455, report issue date Jun. 18, 2024, Korea, 10 pages. [cited by applicant]
Korean Patent Office, Third-Party Submission for related Korean patent application No. 10-2024-0040455, report issue date Jul. 2, 2024, Korea, 2 pages. [cited by applicant]
Ahn et al., Brazing Technology for Heat Exchangers, Journal of KWS, vol. 17, No. 2, Apr. 1999, pp. 9-17. [cited by applicant]
Third Party Submission dated Jul. 28, 2024 in U.S. Appl. No. 18/099,223; 25 pages. [cited by applicant]
United States Patent Office, Notification of Non Final Office Action for related U.S. Appl. No. 17/131,772, report issue date Aug. 16, 2023, 11 pages. [cited by applicant]