Pipeline valve in the media where it plays an important role in cutting off the throttle and stop valve as an extremely important class of truncated valve, the valve stem seal is obtained by applying a torque to the valve stem in the axial direction applying pressure valve so that the valve seat sealing surface sealing surface fit closely to prevent media leaks along the gap between the seal faces.
Cut-off valve sealing surface and the valve sealing seat sealing surface composition, stem drive valve seat along the centerline for vertical movement. Shut-off valve opening and closing process start small height, easy to adjust the flow, and manufacturing easy maintenance, suitable for a wide range of pressures.
Compared with the industrial production is another commonly used cut-off valve type valve eleven trouble, from the structure, the former cut-off valve is simple, easy to manufacture and repair. From life, the valve sealing surface easy to wear and abrasion, no relative sliding between the valve opening and closing process valves and valve seat sealing surface _ and therefore less wear on the sealing surface and scratch, so to improve the seal Vice whole life of the shut-off valve in the fully closed during the valve stroke is small, its height is relatively small valve trouble. The disadvantage is the cut-off valve, opening and closing torque is large and difficult to open and close fast, because the valve body flow passage more twists and turns, big resistance to fluid flow, resulting in a large hydrodynamic losses in the pipeline.