Patent ID: 7108013

Claim:
A relief valve assembly comprising: a casing, said casing having a fist end, and a second end; an one-way valve mounted in the first end of said casing for allowing a fluid to pass through the first end of said casing toward the second end of casing and prohibiting reverse flow of said fluid out of said casing through the first end of said casing; and a relief control valve installed in said casing between the first end and second end of said casing and controllable to discharge said fluid out of said casing through said relief control valve; wherein: said relief control valve comprises: a guide tube fastened to said casing, said guide tube comprising a passage extending through two distal ends thereof in fluid communication between the first end and second end of said casing, said guide tube having a stop flange at one end of the passage of said guide tube; a valve stem axially movable inserted through said guide tube, said valve stem comprising a head for stopping against said stop flange of said guide tube to seal the passage of said guide tube, a stem body extending from said head, a flange extending around the periphery of one end of said stem body, and a groove extending around the periphery between said head and the flange of said stem body; an O-ring mounted in said groove of said valve stem and stopped between said head and the flange of said stem body; and a spring member sleeved onto said stem body and stopped between a part inside said guide tube and one end of said stem body of said valve stem remote from said head of said valve stem to support said valve stem in a close position where said head of said valve stem is stopped against said stop flange of said guide tube and said O-ring is stopped at one end of the passage of said guide tube to block the passage of said guide tube and for enabling said valve stem to be moved axially relative to said guide tube from said close position to an open position to move said head and said O-ring away from said guide tube and to open the passage of said guide tube.