초록 ▼

A pilot operated safety relief valve (14) in which a pilot valve (32) controls the opening and closing of the main valve member (26). The pilot valve (32) has a spindle valve member (70) between an intermediate dome fluid chamber (52) and an exhaust chamber (54) communicating with exhaust port (52)

A pilot operated safety relief valve (14) in which a pilot valve (32) controls the opening and closing of the main valve member (26). The pilot valve (32) has a spindle valve member (70) between an intermediate dome fluid chamber (52) and an exhaust chamber (54) communicating with exhaust port (52) and exhaust line (38). Spindle valve member (70) has an annular sealing member or membrane (104) having a relatively thin body (105) with opposed beads (106, 108) along inner and outer peripheries of body (105) for sealing between spindle valve member (70) and the adjacent retainer sleeve (94). Any positive backpressure forces from exhaust line (38) are balanced against spindle valve member (70) by annular seal (80) and membrane (104). Membrane (104) is effective for sealing between spindle valve member (70) and retainer sleeve (94) without generation of frictional forces therebetween thereby to permit precise actuation of main valve member (70) within the tolerance of the relieving pressure specified for pilot valve (32).

대표청구항 ▼

[What is claimed is:] [9.]a body having three ports in communication with a bore through said body to define a fluid inlet sensing port, a dome port in fluid communication with the piston actuator, and an exhaust port;said body having a fluid inlet sensing chamber in fluid communication with said fl

[What is claimed is:] [9.]a body having three ports in communication with a bore through said body to define a fluid inlet sensing port, a dome port in fluid communication with the piston actuator, and an exhaust port;said body having a fluid inlet sensing chamber in fluid communication with said fluid inlet port, an intermediate dome fluid chamber in fluid communication with said dome port, and an exhaust fluid chamber in fluid communication with said exhaust port;a first valve member between said inlet port and said dome port permitting fluid flow between said inlet sensing chamber and said intermediate chamber in one position and preventing fluid flow between said inlet sensing chamber and said dome chamber in another position;a second valve member positioned between said intermediate fluid chamber and said exhaust chamber normally mounted in a closed position to prevent communication between said intermediate chamber and said exhaust chamber, and movable to an open position to permit fluid communication between said intermediate chamber and said exhaust chamber at a predetermined high set pressure so that fluid pressure in said intermediate chamber is exhausted through said exhaust port when said second valve member is in an open position; said second valve member including an upper spindle mounted for movement within a bore of a retainer member about said spindle;an annular seal on which said second valve member is seated in a closed position during normal operation to block fluid flow between said exhaust chamber and said intermediate chamber; anda conformable annular sealing member between said retainer member and said spindle for sealing between the spindle and the retainer member;said conformable sealing member forming the sole sealing member between said spindle and said retainer member and having an inner periphery freely attached within an annular groove extending about said spindle, said spindle permitting a relatively small movement of said inner periphery transversely of the longitudinal axis of said spindle.