Patent ID: 8057219
Filing Date: 2011-11-15
Classification: F23N

Abstract:
1. A dual fuel gas heater comprising: a gas burner, a first pilot burner, a control valve situated to delivery either a first fuel or a second fuel to the gas burner and to the first pilot burner, a temperature sensor located adjacent the first pilot burner that generates an electrical voltage deliverable to the control valve upon being heated by a pilot flame emitted by the first pilot burner, a normally closed thermal switch located inside or in proximity to the gas burner that is located in the electrical flow path between the temperature sensor and the control valve, the thermal switch configured to open when the temperature of the gas burner exceeds a first control temperature that is indicative of an inappropriate fuel being supplied to the gas burner; and the control valve configured to close when the temperature sensor falls below a second control temperature or when the normally closed thermal switch assumes an open position.