Explosion barring shutoff device

摘要

A shutoff device comprises a housing having a closable flow passage which is closed by a closing plate member which moves into a recess defined in said housing forming a receiving seat. The closing plate member is closed by the movement of a fluid pressure operated piston which moves the closing plate member rapidly into the closed position. In order to prevent the closing plate member from slamming into the valve seat and damaging the valve seat, there is provided a bolster member in the form of a stop which is disposed in the path of movement of a stop face connected to a piston rod of the fluid pressure's piston which is connected to the closing member. The bolster member is made of a material which is non-elastic but which deforms after it is contacted by the stop face to initially stop the closing plate member and is then deformed to permit final closing of movement of the closing plate member into a completely closed position engaged in the recess seat and also to absorb the closing force by its own deformation.