Temperature relief valve with thermal trigger

Abstract

A thermal relief device releases gas from a storage cylinder when a thermal trigger senses a predetermined temperature threshold. The thermal relief device includes a valve body which has a passage for communication with the interior of the cylinder. A pilot valve assembly is disposed within the valve body and has a popper for blocking the flow path. The poppet has a longitudinal passage extending through the popper. A metal diaphragm sealing the passage of the poppet has a first side exposed to the interior of the cylinder and a second side opposite the first side exposed to the outlet. A hollow bayonet is mounted in alignment with the passage of the popper on the outlet side of the disk and is moveable between a first position and a second position. In the first position, the bayonet is spaced from the disk in the passage, and in the second position the bayonet pierces the disk. A spring is used to biased the bayonet toward the disk. A thermal trigger is operably coupled to the bayonet for holding the bayonet in the first position until the thermal trigger reaches a predetermined temperature threshold. Upon reaching the predetermined temperature threshold, the thermal trigger releases the bayonet so that the bayonet moves to the second position and pierces the disk. When the disk is pierced, the popper is moved out of the flow path and gas is allowed to escape from the cylinder.