Flame ignition

Claim 1

For controlling the operation of a plurality of gas fuel burners having respective electrically operable fuel valves which supply fuel to said burners when respectively energized, an ignition and fuel control system comprising in combination: a source of alternating current power one side grounded and connected to said burners, a plurality of spark gaps each positioned relative to a respective burner to ignite fuel issuing therefrom when energized, a plurality of single electrodes each positioned relative to a respective burner so as to be enveloped by flame from the burner, a combined Ignition and control circuit having connections extending to said source of power, across said spark gaps, individually to said respective electrodes, and to said respective valves, comprising a capacitive discharge spark generator when operable applying voltage pulses across said spark gaps to energize them simultaneously, a plurality of like control sections each comprising connections extending to a respective burner switch thereby to control the operation of the respective burners, valve energizing means including a silicon controlled rectifier, a relay and a capacitance resistance holding circuit adapted to energize the relay for a predetermined period of time in response to a pulse of voltage on the gate of the silicon controlled rectifier, starting pulse means including a diode, a capacitor and a resistance adapted to provide several pulses of voltage to said silicon controlled rectifier only when power is initially applied to the control circuit and not thereafter until its respective burner switch has been opened, flame responsive means adapted to render operative said spark generator in the absence of flame at the burner and not otherwise, a circuit connecting a respective electrode through a resistor and a gas discharge device to the ungrounded side of said source of alternating current power through said burner switch with a series combination of a capacitor and a resistor across said discharge device adapted to apply pulses of voltage to the gate of said silicon controlled rectifier when said electrode is enveloped in flame from the burner, and power disconnect means in the line to said burner switch responsive to a significant increase in the average current above the normal current drawn by said control section.