US 11,719,437 B2
System and method for operational control of a water heater apparatus with a combustible gas burner
Michele Bortoliero, Monselice (IT); Massimo Giacomelli, Venice (IT); and Giancarlo Pirovano, Martellago (IT)
Assigned to SIT S.P.A., Padua (IT)
Filed by SIT S.p.A., Padua (IT)
Filed on Dec. 21, 2020, as Appl. No. 17/128,443.
Claims priority of application No. 102019000025351 (IT), filed on Dec. 23, 2019.
Prior Publication US 2021/0190316 A1, Jun. 24, 2021
Int. Cl. F23Q 9/14 (2006.01); F23N 1/00 (2006.01); F24D 19/10 (2006.01); F24H 9/20 (2022.01); F24H 1/18 (2022.01)
CPC F23Q 9/14 (2013.01) [F23N 1/005 (2013.01); F24D 19/1051 (2013.01); F24H 9/2035 (2013.01); F23N 2229/00 (2020.01); F24H 1/186 (2013.01)] 10 Claims
OG exemplary drawing
 
1. A control system for operational control of a water heater apparatus with a combustible gas burner, the apparatus comprising:
a pilot burner (4) for generating a pilot flame,
a main burner (3) for generating a main flame,
a valve group comprising a pilot valve (8) upstream of the pilot burner (4) in order to open/intercept a direct flow of gas to the pilot burner and to a main valve, the main valve (6) being positioned upstream of the main burner in order to open/intercept a direct flow of gas to the main burner, the pilot valve and main valve being electrical control valves,
the pilot burner (4) being controlled as a burner with an intermittent-type pilot flame, the control system comprising
a control unit (10) configured to operationally control the pilot valve (8) and main valve (6),
a flame detection electrode (12) which is provided to be introduced into the flame of the pilot burner (4) and which is configured to conduct an ionization current which is generated by ionizing effect produced by the flame,
wherein the control unit (10) is configured to carry out a measurement or to detect a variation involving increase or decrease of ionization current intensity detected in the flame detection electrode (12), the variation in the ionization current intensity being generated during a change between a first condition, in which the ionization current is indicative of an ignition state of only the pilot burner (4), and a second condition, in which the ionization current is indicative of a simultaneous ignition state of the pilot burner (4) and the main burner (3) so that, by the detection of the measurement or the variation of ionization current, an effective ignition of the main burner (3) is recognized, and wherein the control unit (10) is configured to introduce a delay time (t′) between an instruction to close the main valve (6) and an instruction to close the pilot valve (8), during the delay time (t′) the ionization current being measured or a variation of the ionization current being detected in order to identify an effective extinguishing of the main burner (3).