AFSLUITER.

摘要

A valve comprises a casing having a passageway therethrough for the flow of fluid with a bore intersecting the passageway. A flow regulating member is rotatably mounted in the bore for blocking the passageway in a valve closed position of the flow regulating member. The flow regulating member has a port therethrough for connecting and being in communication with the passageway in a valve open position. The flow regulating member and the casing define a first chamber at one end of the flow regulating member. A stem is rotatably mounted within the casing and is mechanically coupled to the flow regulating member to rotatably drive the flow regulating member within the casing. The stem has an annular rim formed toward and positioned within the first chamber. At least one annular seal surrounds the stem to effect the seal between the stem and the casing. Valving and/or porting is provided for introducing a pressure equal to or greater than the line pressure into the first chamber whereby the pressure acts on the annular rim to move the stem in an axial direction to compress the annular seals.