US Patent 6935364 Magnetically-operated relief valves

A valve comprising a housing having an inlet and spaced therefrom an outlet, a passageway extending between the inlet and the outlet, and a mechanism located in the passageway for controlling the flow of a fluid between the inlet and the outlet, the mechanism including a valve assembly movable between a first open position spaced from a co-operating valve seat and a second closed position at which the valve assembly sealingly engages the valve seat, in which the valve assembly is biased towards the second closed position using a magnet-operated mechanism.