Self-powered intermittent ignition and control system for gas combustion appliances

A self-powered control system for a gas-fired appliance having a pilot burner and a main burner comprising;

• a two-stage valve comprising:
• an inlet for connection to a source of fuel gas;
• a normally closed first stage valve on the gas inlet;
• a main outlet for connection to the main burner of a gas-fired appliance;
• a normally closed second stage valve between the first stage valve and the main gas outlet;
• a pilot outlet between the first and second stage valves for connection to the pilot burner of the gas-fired appliance;
• means for opening the first stage valve and electromagnetically latching the first stage valve in the open position;
• means for opening the second stage valve and electromagnetically latching the second stage valve in the open position;
• an emissive surface for heating by the flame of the pilot burner;
• a photovoltaic device exposed to radiation from the emissive surface, the output of the photovoltaic device being connected to the means for electromagnetically latching the first stage valve for maintaining the first stage valve open when the photovoltaic device is irradiated from the emissive surface and releasing the first stage valve for closing when the photovoltaic device is not irradiated;
• and
• means in the flame of the mainburner and coupled to the means for electromagnetically latching the second stage valve for maintaining the second stage valve open when the main burner is burning and releasing the second stage valve for closing when the main burner is not burning.