| 摘要 |
A ball valve operable between a fully-open position and a closed position for regulating fluid flow includes a valve body machined and arranged with a flow passageway extending completely therethrough and receiving at each end a fluid fitting for coupling to flow lines. Disposed within the interior of the valve body is a ball plug member which is supported below by a stem and needle bearing arrangement and is operable to be turned 90 degrees by a handle, stem and bonnet arrangement. The internal position of the ball plug member is maintained by a pair of ball seats which are centrally disposed within the flow passageway and are held in position by means of adapter cylinders which are in turn held in position by retainer plates. In order to maintain spring-loaded pressure and to provide a sealed interface between the ball seat and the adapter cylinder, spring seal assemblies are disposed within the adapter cylinder and between the ball seat and corresponding retainer plate. These spring seal assemblies each include an annular seal portion arranged to fit in the corner intersection of the ball seat and adapter cylinder, a conical positioning ring, a back-up ring and a Belleville washer which is in turn backed up by the corresponding retaining plate.
|
