Patent ID: 7014164

Claim:
A shut-off device for protection against explosion in a pipe-line, said shut-off device comprising: a piston slidably disposed in a cylinder so as to define a working chamber in said cylinder; a pressure medium housing surrounding said cylinder and forming a pressure medium reservoir, said housing having an end wall forming an end face of the pressure medium reservoir, said end wall defining a pressure chamber outlet port and a connecting duct leading to the working chamber of said cylinder, wherein said cylinder is arranged within said pressure medium reservoir, and said end wall of said housing delimits the working chamber of said cylinder; a slide valve plate slidable transversely to a direction of flow; a piston rod connecting said slide valve plate to said piston; and at least one closing valve for permitting selective communication between said pressure medium reservoir and said working chamber to permit actuation of said piston by a pressure medium and thereby move said slide valve plate to a closing position, said closing valve being fitted in said end wall of said pressure medium housing and having a valve disk for selectively closing said connecting duct, wherein said outlet port surrounds at least a portion of said connecting duct.