Abstract: A non-flowing pilot valve (16) for a control valve (C) in a main flow line (F) having a body (27) with an inlet fluid chamber (76), an outlet fluid chamber (106) and an intermediate fluid chamber (104) between the inlet fluid chamber (76) and the outlet fluid chamber (106). Diaphragm (34) in the fluid inlet chamber (76) is secured to a piston slidable body (40) extending within intermediate fluid chamber (104) and having a valve seat (88) thereon between inlet fluid chamber (76) and intermediate fluid chamber (104). A second fixed valve seat (64) is provided within the body (40) between the intermediate fluid chamber (104) and the outlet fluid chamber (106). A valve spool (92) has a pair of O-ring seals (94, 96) thereabout adapted to seal against the valve seats (88, 64).

Abstract: A check valve having a body with an inlet, an outlet, a valve seat surrounding communication between said inlet and said outlet, a valve chamber in said body communicating with said outlet, a bonnet having a cylinder therein with the open end communicating with said valve chamber where the bonnet is secured to said body, a valve disc resiliently secured to an arm which is pinned to allow the valve disc to be pivoted from a position engaging said valve seat to a position in said valve chamber, a piston in the bonnet cylinder and having a connecting rod secured to said valve disc arm so that said piston reciprocates in said cylinder as said valve disc moves, a port through the piston to allow passage of the fluid flowing through the check valve to flow to opposite sides of the piston as it reciprocates in the cylinder, a reed valve secured to said piston and adapted to substantially close said port during closing movement of said valve disc but allow relatively free flow of fluids through said port during openi