Melting safety device for gas system of hydropneumatic pressure accumulators

Claim 1

A safety device for controlling discharge of gas from a gas system, particularly of a hydropneumatic pressure accumulator, comprising: a discharge passage; a normally closed first valve positioned in and controlling fluid flow through said discharge passage; a control member mounted adjacent said first valve for movement along a path between a rest position in which said control member is operationally disengaged from said first valve allowing said first valve to remain closed and an operative position in which said control member engages said first valve forcing said first valve open; power means, coupled to said control member, for moving said control member from the rest position to the operative position; a blocking member projecting into the path of movement of said control member and releasably retaining said control member in the rest position, said blocking member being formed of a material that melts upon exposure to an unexpected temperature increase; and a normally closed second valve arranged in said discharge passage adjacent said blocking member in series with said first valve, said second valve having a sealing element and being opened upon melting of said blocking member; whereby, upon melting of said blocking member, said power means moves said control member to the operative position opening said first valve and said discharge passage.