science and kükenabdichtung for a ball valve

摘要

The specification and drawings show a ball valve including a housing defining a valve chamber with inlet and outlet passages connected to the chamber. A ball having at least one throughflow aperture is positioned within the chamber and arranged for selective rotation by a cylindrical stem which extends from the chamber. Resilient, resinous material substantially fills the chamber and sealingly engages the outer surface of the ball and the inner walls of the chamber. Packing means are disposed about the stem and include a relatively rigid first gland member closely and slidably received in the housing and having an opening through which the stem extends. A first surface of the gland is engaged with the resinous material in the chamber. A recess is formed in the gland member about the inside of the opening. Preferably, the recess has a substantial length axially of the stem. An elongated bushing of resilient, resinous material is positioned in the recess and adjustable means are provided for applying a compressive loading axially of the bushing in a direction toward the first surface to compress the bushing into sealing engagement with the stem and cause the gland member to apply a compressive load on the resinous material within the chamber. Preferably, the bushing is formed from polytetrafluoroethylene or the like.