The valve plays an important role in the cutting and throttling of the medium in the pipeline in which it is located. The shut-off valve is an extremely important type of shut-off valve. The seal is applied by applying torque to the valve stem, and the valve stem is oriented in the axial direction. The flap exerts pressure so that the disc sealing surface fits snugly against the seat sealing surface, preventing the medium from leaking along the gap between the sealing faces.
The sealing pair of the shut-off valve is composed of a valve sealing surface and a valve seat sealing surface, and the valve stem drives the valve flap to move vertically along the center line of the valve seat. During the opening and closing process of the shut-off valve, the opening height is small, the flow rate is easy to adjust, and the manufacturing and maintenance are convenient, and the pressure is applicable to a wide range.
Compared with another commonly used cut-off type valve in industrial production, the shut-off valve is structurally simpler than the former, and is easy to manufacture and repair. In terms of service life, the sealing surface of the shut-off valve is not easy to wear and scratch, and there is no relative sliding between the valve flap and the sealing surface during the valve opening and closing process, so the wear and scratch on the sealing surface are small, so the sealing is improved. The service life stop valve of the auxiliary service has a small valve stroke during the full-closed process, and its height is relatively small compared to the alarm valve. The disadvantage of the shut-off valve is that the opening and closing torque is large and it is difficult to achieve rapid opening and closing. Because the flow passage in the valve body is relatively tortuous, the fluid flow resistance is large, and the fluid power is greatly lost in the pipeline.