Fuel security device

Abstract

A security device for a fuel such as natural gas having a series circuit of a relay switch, a hazard detecting switch, a relay switch operating coil and a timer. A valve coil is adapted to open and close a main fuel supply valve. The valve coil is connected in parallel to the series circuit. A reset switch is adapted to excite the valve coil and is connected in parallel with the relay switch. In one embodiment, the hazard detecting switch, the relay switch operating coil and the valve coil are coupled through a transformer in series with an electric source. The hazard detecting switch the relay switch operating coil and the valve coil are disposed on a secondary side of the transformer. The main fuel supply valve is normally closed such that in case of a power failure, the valve will close and remain closed.

Dependencies are inferred from the claim text.