Fluid pressure relief system for pressure vessels

摘要

A pilot operated safety relief valve for a vent (16) in a pressure vessel (10) is described which comprises: a value housing (142) mounted on said pressure vessel (90) over said vent (16) and defining a main valve chamber (156) in continuous fluid communication with said vent (16) and said pressure vessel (10); a valve seat (166) in said main valve chamber (156) defining an outlet for said valve chamber (156); a main valve member (172) mounted on said valve seat (166) adjacent one end of said valve chamber (156) for reciprocable movement between a seated closed position on said valve seat (166) and an unseated open position relative to said valve seat (166); an operating rod (174) secured adjacent one end to said main valve member (172); fluid pressure responsive means operatively connected to the other end of said operating rod (174) adjacent the other end of said valve chamber (156) responsive to a predetermined fluid pressure in said pressure vessel (10) and said valve chamber (156) to permit movement of said main valve member (172) to an open position, said fluid pressure responsive means comprising a fluid responsive member (176) connected to the other end of said rod (174) and defining an inner fluid chamber (182) on one side of said fluid responsive member (176) adjacent said valve member (172) and an outer fluid chamber (186) on the other side of the fluid responsive member (76) remote from said valve member (172), and a pilot valve (190) in fluid communication with said inner fluid chamber (182) for normally controlling the opening and closing of said main valve member (172), said main valve member (172) being continuously urged to an open position by fluid pressure from said pressure vessel (10). The outer fluid chamber (186) in one embodiment is in communication with atmosphere. In another embodiment it is in fluid communication with said pressure vessel (1) to assist in opening of said main valve member (172c), In that case there is also means providing fluid communication between said inner fluid chamber (182c) and said outer fluid chamber (186c) under predetermined operating conditions to permit and equalization of fluid pressure in said inner and outer fluid chambers (182c, 186c).