Heat operated fire extinguisher

Claim 1

Automatic fire extinguishing apparatus provided with a container for storing fluid under pressure and having a discharge passage, a closure for controlling the discharge of fluid including a valve seat and a movable valve member to cooperate with the seat to close the passage, said apparatus comprising: a pressure surface on the valve member communicating with pressurized fluid in the container to produce a force tending to open the valve; a heat-sensing control head connected at one end to the closure na having a bore communicating with the discharge passage, said head including means for conducting ambient heat to interior wall surfaces of said bore and having a plurality of openings adjacent the other end and extending radially through the sidewall thereof to said bore; a piston member forming part of the valve member and adapted to fit within said bore; and an elongated body of heat fusible material positioned within said bore and being engaged by and substantially surrounded by said interior wall surfaces, said body engaging said piston member to hold the valve closed against said opening force, and being adapted to convert from a solid state to a flowable state in the presence of a predetermined ambient temperature, whereby said body in the flowable state is moved by said piston to flow through said openings as the valve member moves in response to said opening force.