US Patent 9562619 Safety valve

A safety valve includes: a valve element; a valve seat that has a gas release hole from which a gas is released and a protrusion that protrudes towards the valve element; and a meltable body that is made of a material capable of being melt at an abnormal high temperature. At a temperature other than the abnormal high temperature, the meltable body limits displacement of the valve element to thereby prevent inflow of the gas towards the gas release hole. At the abnormal high temperature, the meltable body is melt, thereby the valve element is displaced and the gas is released from the gas release hole.