GB1240957A - Igniter system for gas burners - Google Patents

Abstract

1,240,957. Igniter system; SCR control Circuits. FENWAL Inc. 24 Feb., 1970 [10 March, 1969], No. 8741/70. Headings F4F and F4T. [Also in Division H3] In an igniter system for a plurality of gas burner locations, an energy storage capacitor CE is connected in series with primary windings W1 and W2 of a spark coil 30, a rectifying diode D1 and a current-limiting resistor RL across a pair of leads L1 and L2 supplying alternating current, the energy storage capacitor CE being discharged through an SCR Q1 when the SCR is triggered by any of timing capacitors C1-C4 discharging through a corresponding neon lamp N1-N4, the appropriate timing capacitor being charged through a corresponding resistor R1- R4 when a corresponding switch S1-S4 (coupled to corresponding gas valves 21-24) is opened, so that the appropriate timing capacitor is no longer shunted to earth. The discharge of storage capacitor CE through the primaries W1 and W2 causes a high voltage pulse across each of the secondary windings W3 and W4, the ends of which are connected to electrodes 31-34, positioned adjacent to burners 11-14 respectively, producing sparks to ignite the burner when supplied with gas. Electrodes 41- 44 are also situated adjacent to the corresponding burners and, when ignition has taken place, provide a conduction path via the burning gas to shunt the corresponding timing capacitor to earth to prevent its being charged to the breakdown voltage of the corresponding neon lamp. Instead of the switches S1-S4, normally open switches (not shown) in series with each charging resistor R1-R4 may be provided to prevent each capacitor from charging when the fuel supply to the respective burner is cut off, each switch being closed when the corresponding one of valves 21-24 is opened. The igniter system may be used with a single burner for which it is desired to provide flame sensing and ignition at several locations. In this case, a single switch may be used to de-energize the entire circuit when ignition has taken place.