| 摘要 |
A safety valve (14) adapted to be inserted within a flowline (10) comprises an elongate valve body (16) having central bore (24) with a fluid inlet (40) and a fluid outlet (42) in fluid communication with the bore (24). A slidable valve element (50) having a fluid passage (62) therein is mounted within the bore (24) and is slidable between the seated and unseated positions. A stop member (108) is mounted on the valve body (16) for relative movement between extended and retracted positions and has a stem which extends within the bore (24) along the longitudinal axis of the valve body (16). During normal operation valve element (50) is in a seated position and stop member (108) is in a retracted position, and thus, fluid flows from the fluid inlet (40) to the fluid outlet (42). However, in the event fluid pressure at the fluid outlet (42) decreases, the pressure at the fluid inlet (40) moves the valve element (50) into its unseated position wherein the stem abuts the valve element (50) and blocks fluid flow through the valve element (50) to the fluid outlet (42). A sealing ring (70) carried by valve element (50) adjacent the inlet port (66) provides a fluid-tight seal between the inlet port (66) and fluid inlet (40) only in the unseated position of the valve element (50).
|
