Quiet safety relief valve

In a relief valve including a body, inlet means formed in said body, outlet means formed in said body, a valve assembly between said inlet and outlet means and movable between a closed position and an open position, means for moving said valve assembly between the closed and open position, and means biasing said valve assembly to its closed position;

• the improvement wherein said means biasing said valve assembly comprises the combination of spring means acting between said body and said valve assembly, first fluid pressure means acting on said valve assembly, the net biasing force acting on the valve being the spring force plus the first fluid pressure force, wherein said means for moving said valve assembly includes second fluid pressure means acting on said valve assembly to move said valve assembly to its open position, wherein said valve assembly comprises a valve stem received for axial sliding movement in said body, and a sealing element attached to an end of said valve stem, including a piston element attached to said valve stem, wherein said body comprises a lower section, an intermediate section attached to said lower section, and an upper section attached to said intermediate section, a portion of said intermediate section defining a cylinder in which said piston element is received, including a wall member received between said intermediate section and said upper section and substantially closing one end of said cylinder, a first fluid inlet port formed in said intermediate section and opening into said cylinder on a first side of said piston element, and a second fluid inlet port formed in said intermediate section and opening into said cylinder on a second side of said piston element;
• and, wherein said piston element comprises a hub portion received on said valve stem and extending through said wall member, and a disk portion including peripheral sealing means acting against the interior wall of said cylinder.