Patent ID: 7044729
Filing Date: 2006-05-16
Classification: F23N

Abstract:
1. A combustion control system having at least one gas burner with a main flame adapted to a domestic bake oven, comprising: a thermostat valve provided with a regulator valve member and a valve body with a gas inlet and at least one gas flow outlet to be supplied to the burner, wherein the gas flow has been modulated by a temperature sensor of a hydraulic type in cooperation with mechanical means for actuating on the regulator valve member; said thermostat valve having a built-in safety valve housed in said gas inlet, whose actuator electromagnet is kept energized by a thermocouple heated by the main flame after the end of an initial heating time period, and a rotary hand knob which actuates the safety valve mechanically opening it; an electric microswitch operated by means of the thermostat valve hand knob; an electronic module for controlling the burner which connected to the AC voltage supply by way of said microswitch, comprising a spark igniter with an ignition electrode activated during a pre-ignition step with a preset time of short duration, a flame detection circuit connected to a flame current rectification electrode, a circuit supplying a DC voltage to said electromagnet, for the maintenance of the safety valve open, and a timer circuit for a temporary connection of said DC voltage supply circuit to the electromagnet; wherein during said pre-ignition step initiated by the microswitch, the flame detection circuit is connected to said AC voltage supply in combination with the timer circuit for supplying the DC voltage to the safety valve electromagnet, and temporary maintenance of the gas flow without the manual assistance of the rotary knob; and the timer circuit enabling the DC supply circuit for an interval of time, the interval of time depending on a result obtained from the flame rectification detector during the preset short time within the pre-ignition step, to maintain the energization of the safety valve if a flame is detected.