Importance

Loading Importance Indicators...

Abstract

A plurality of burners are provided for burning a combustible gas mixture. A conduit extends to each of the burners for supplying a combustible gas mixture thereto. A mixing device is coupled between the conduit and a source of air and a source of combustible gas for mixing combustible gas and air for flow to the conduit. An air valve is coupled between the source of air and the mixing device for controlling the flow of air to the mixing device. First and second gas valves are coupled between the source of combustible gas and the mixing device. A control circuit is provided which is adapted to be operated in a flame intensity cycle of high/low flame or in a burner on/off cycle. In the flame intensity cycle, flow of air through the air valve is cyclically increased and decreased and gas flows continuously through the second gas valve for cyclically increasing and decreasing the flame intensity at each of the burners. In the burner on/off cycle, the second valve is cyclically opened and closed whereby it is opened for a first time period and closed for a second time period during each cycle. During each cycle, the first gas valve is opened at the same time that the second gas valve is opened for allowing additional combustible gas to flow to the mixing device. At a delayed time following the beginning of the first time period and before the end of the first time period of each cycle, the first gas valve is closed and the flow of air through the air valve to the mixing device is reduced. At the end of the first time period of each cycle, the second gas valve is closed and the flow of air through the air valve is increased.

Loading the Abstract Image...

First Claim