Intermittent pilot igniter and valve controller for gas burner

Claim 1

In a pilot ignition and valve control system for a gas burner having a main burner, a main valve operated by a main solenoid for providing gas to said main burner, a pilot burner, a pilot valve operated by a pilot solenoid for providing gas to said pilot burner, and a flame sensor and ignition electrodes adjacent said pilot burner, the combination of: a pair of input terminals for connection to an ac power source through a thermostat switch, and for connection to said pilot solenoid whereby said pilot solenoid is energized and gas is supplied to said pilot burner when the thermostat switch is closed; a first storage capacitor; a flame sensor voltage step-up transformer with a primary winding connected across said input terminals and a secondary winding connected to said first capacitor forming a series combination for connection across said flame sensor and pilot burner; an ignition circuit for connection to said ignition electrodes; a first switching circuit connected across said input terminals and operable between a first condition connecting said input terminals to the input of said ignition circuit turning said ignition circuit on to provide sparking at said electrodes, and a second condition connecting said input terminals to said main solenoid turning said ignition circuit off and supplying gas to said main burner; and a control circuit for said switching circuit, said control circuit comprising a field effect transistor, a second storage capacitor, a first diode, first means connecting the gate of said transistor to the junction of said transformer secondary winding and said first capacitor, second means connecting the source and drain of said transistor in series with said second capacitor and first diode across said input terminals, a first resistor connected across said source and drain and second capacitor, and third means connecting the transistor and second capacitor interconnection to said switching circuit in controlling relation whereby a flame sensed at said pilot burner actuates said switching circuit from said first condition to said second condition.