HIGH PRESSURE BALL VALVE

摘要

A ball valve designed for high pressure shut-off at fluid pressures approaching the ultimate compressive stress of plastic annular seat rings which are employed. The ball member is trunnion mounted in order to carry the total force of the shut-off pressure and the seat rings are disposed in seat ring carriers. Each seat ring includes a spherical ball engaging surface having a radius slightly smaller than the radius of the ball. Each carrier is continuously urged toward the ball by a plurality of disc springs in order that the seat ring engaging surfaces will be in continuous sealing engagement with the ball surface. The seat ring engaging surfaces are configured so that at least the areas thereof located adjacent the outer diameters will be first to sealingly engage the ball. The valve components are configured and dimensioned to limit the effective area on which fluid pressure may act in urging the seat rings into ball contact for thus controlling compressive stresses which may be exerted on the plastic seat ring material. Also, fluid pressure urges the seat rings toward the ball to enhance sealing engagement with the ball regardless of the position of each seat ring upstream or downstream of the ball from the source of fluid pressure and also with the valve in the open position. The inventive concept involved may advantageously be employed in a variety of valve bodies to accommodate a plurality of fluid shut-off applications.