DETAILED ACTION
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and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114.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 12/12/2025 has been entered.
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.
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.
Claim(s) 1, 3, 5, 8, 9, 12-14, 21 is/are rejected under 35 U.S.C. 103 as being unpatentable over Gullapalli (US 20210404650 A1) in view of Coupe (GB 765175 A), and Wada (US 20180119989 A1).
Regarding claim 1, Gullapalli discloses a heat exchanger including an apparatus for lighting a burner, the heat exchanger comprising:
a combustion chamber having a wall lined with a refractory material (Fig. 1, 100), wherein the refractory material includes a refractory material opening (Fig. 4, ignitor opening 104); and
an ignition rod assembly (300) extending through the refractory material opening (para. 43).
Gullapalli fails to disclose:
wherein the ignition rod assembly comprises:
a sleeve fixed to a ground rod, wherein the sleeve extends through the refractory material opening;
a sleeve opening provided in the sleeve to facilitate air flow from the combustion chamber into the sleeve, wherein air is drawn from the combustion chamber and into the sleeve opening via the refractory material opening; and
a flame ionization rod insulator surrounding a flame ionization rod, wherein the flame ionization rod extends into the combustion chamber.
Coupe teaches an ignition rod assembly comprising:
a sleeve (8) fixed to a ground rod (12), wherein the sleeve extends through an opening of the combustor wall (Figure); and
a sleeve opening (9) provided in the sleeve to facilitate air flow from the combustion air chamber into the sleeve.
It would have been obvious to a person skilled in the art at the time of effective filing of the application to modify Gullapalli wherein the ignition rod assembly includes a sleeve fixed to a ground rod, wherein the sleeve extends through the refractory material opening; a sleeve opening provided in the sleeve to facilitate air flow from the combustion chamber into the sleeve, wherein air is drawn from the combustion chamber and into the sleeve opening via the refractory material opening.
With the modification, the ignitor of Coupe would be inserted and positioned within the refractory material opening (Gullapalli, opening 104). The sleeve of the ignitor would receive combustion air from the combustion chamber via the refractory material opening (para. 33 of Gullapalli discloses that the ignitor 300 receives combustion air from the combustion chamber).
The motivation to combine is to provide a reliable ignitor that is suitable for the heat exchanger of Gullapalli (Note: Gullapalli is silent regarding the details of the ignition rod assembly). Reliable ignition is important to ensure consistent water heating performance.
Wada teaches a heat exchanger having an ignition rod assembly, the ignition rod assembly comprising:
a flame ionization rod insulator (Fig. 3, 14c) surrounding a flame ionization rod (Fig. 6, 14b) (para. 70), wherein the flame ionization rod extends into the combustion chamber (Fig. 3 shows the rod extending into the combustion chamber defined by the walls 11a-d).
It would have been obvious to a person skilled in the art at the time of effective filing of the application to modify Gullapalli wherein the ignition rod assembly includes a flame ionization rod insulator surrounding a flame ionization rod, wherein the flame ionization rod extends into the combustion chamber. With the modification, the ignitor of Coupe would be modified to have a flame ionization rod and another ground electrode, and these two elements would be integrated and fixed with the ignitor of Coupe. The motivation to combine is to provide a flame sensing device that can inform a controller whether a pilot/ignition flame is present or not. If a flame is not detected, then the controller can reignite the flame, thereby ensuring reliable pilot burning operation.
Regarding claim 3, modified Gullapalli discloses the heat exchanger of claim 1, except further including a mounting plate designed to seal the wall opening formed in the wall of the heat exchanger, wherein the mounting plate is mounted outside of the combustion chamber of the heat exchanger.
However, Coupe teaches a mounting plate designed to seal the wall opening formed in the wall of the combustor (Figure shows a plate that is connected to the sleeve 8, is perpendicular to the sleeve, and is sandwiched between the block 13 and the chamber wall), wherein the mounting plate is mounted outside of the combustion chamber of the heat exchanger.
It would have been obvious to a person skilled in the art at the time of effective filing of the application to modify Gullapalli to further include a mounting plate designed to seal the wall opening formed in the wall of the heat exchanger, wherein the mounting plate is mounted outside of the combustion chamber of the heat exchanger. The motivation to combine is to prevent combustion gases from leaking into the outside environment, and to prevent unwanted air intrusion into the combustion chamber.
Regarding claim 4, modified Gullapalli discloses (see Wada for citations) wherein the flame ionization rod is electrically connected to a terminal located outside of the combustion chamber of the heat exchanger (Fig. 7: a flat connector is shown on the rear end of rod 14b; this flat connector suggests an electrical connection with a wire for sending information from the flame ionization rod 14b to a controller; furthermore, it would have been obvious to connect the flat connector with a wire, so that signals from the flame ionization rod can be sent to the controller).
Regarding claim 5, modified Gullapalli discloses (see Wada for citations) wherein the terminal further includes a terminal insulator (Figs. 7, 16; EP1/CP) provided in the form of a material that is heat resistant and electrically insulating (para. 104).
Regarding claim 8, modified Gullapalli discloses the heat exchanger of claim 1, wherein the sleeve is connected to a fuel orifice mount (Coupe discloses a mount 13 which contains a fuel orifice 14) located outside of the combustion chamber of the heat exchanger, except where the fuel orifice mount is a gas fuel. However, Official Notice is taken that using gas fuel for an ignitor is well-known and common knowledge, and it would have been obvious to a person skilled in the art at the time of effective filing of the application to modify the ignitor of Coupe (which was incorporated into Gullapalli) to operate with gas fuel because it’s widely available and accessible.
Regarding claim 9, modified Gullapalli discloses (see Wada for citations) discloses wherein the flame ionization rod is configured to monitor current flow in the ignition rod assembly (para. 71).
Regarding claim 12, modified Gullapalli discloses the heat exchanger of claim 8, and suggests wherein the gas orifice mount is configured to be press-fit into the sleeve. The Figure of Coupe suggests the fuel orifice mount (13) is press-fit into the sleeve (8).
t would have been obvious to a person skilled in the art at the time of effective filing of the application wherein the gas orifice mount is configured to be press-fit into the sleeve, so that there is a strong leakproof connection between the sleeve and the gas orifice mount.
Regarding claim 13, modified Gullapalli discloses or suggests wherein the sleeve (Coupe, 8) comprises a slot (opening at the upper end in Coupe) designed to retain the ground rod (Coupe, 12) via a press fit connection or via welding (the Figure in Coupe suggests a tight fit, i.e., press fit connection, between the ground rod 12 and element 13, and there is a tight fit connection between element 13 and the sleeve 8; It would have been obvious to a person skilled in the art at the time of effective filing of the application wherein the sleeve comprises a slot designed to retain the ground rod via a press fit connection, so that the ground rod can be held in place).
Regarding claim 14, modified Gullapalli discloses (see Wada for citations) wherein the flame ionization rod is provided in a hook shape (Fig. 4).
Regarding claim 21, modified Gullapalli discloses wherein the spark is generated in a gap between the flame ionization rod (Wada, 14b) and the ground rod (Wada, 14a) (Wada, para. 70).
Claim(s) 16, 18, 19 is/are rejected under 35 U.S.C. 103 as being unpatentable over Gullapalli (US 20210404650 A1) in view of Coupe (GB 765175 A), and Wada (US 20180119989 A1), as applied to claim 1, and further in view of Torii (US 20070216275 A1).
Regarding claim 16, Gullapalli fails to disclose wherein the ground rod is grooved or coated with other alloy materials. However, Torri teaches coating a ground electrode with a nickel alloy (abstract). It would have been obvious to a person skilled in the art at the time of effective filing of the application to modify Wada’s ground rod, which was incorporated into Gullapalli, to be coated with other alloy materials to protect the ground rod from corrosion and high temperatures.
Regarding claim 18, Gullapalli fails to disclose wherein the flame ionization rod is coated with an alloy material suitable for heat resistance, oxidation resistance, or low electric resistance. However, Torri teaches coating an electrode with a heat resistant nickel alloy (abstract). It would have been obvious to a person skilled in the art at the time of effective filing of the application to modify the flame ionization rod of Wada (which was incorporated into Gullapalli) wherein the ground rod is coated with other alloy materials to protect the flame ionization rod from corrosion and high temperatures.
Regarding claim 19, Gullapalli fails to disclose wherein the flame ionization rod is made from alumina, KanthalTM, or Nichrome. However, Torri teaches covering an electrode with alumina (para. 45). It would have been obvious to a person skilled in the art at the time of effective filing of the application to modify the flame ionization rod of Wada (which was incorporated into Gullapalli) wherein the flame ionization rod is covered with alumina to protect the flame ionization rod from corrosion and high temperatures.
Allowable Subject Matter
Claims 6, 7 are objected to as being dependent upon a rejected base claim, but would be allowable if rewritten in independent form including all of the limitations of the base claim and any intervening claims.
Claim 22-24 are allowed.
Reasons for Allowance
Claims 22-24 are allowed because of the integration of the gas venturi with the rest of claim 22.
Response to Arguments
Applicant’s arguments with respect to claim(s) have been considered but are moot because the new ground of rejection does not rely on any reference applied in the prior rejection of record for any teaching or matter specifically challenged in the argument.
Conclusion
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/JASON LAU/ Primary Examiner, Art Unit 3762