Cut-off valve, also called shut, is one of the most widely used valves, it is widely welcomed because of the closing process of the sealing surface between the friction small, relatively durable, open height is not small, easy to manufacture, easy to maintain, not only applicable to medium and low pressure, but also applicable to high-pressure. Cut-off valve closure principle is to rely on the pressure of the valve, so that the disc sealing surface and the seat sealing surface tightly fitting, prevent the flow of media. China's valve "three to" has stipulated that the cut-off valve to the direction of the use of top-down, so the installation of directional. Cut-off valve structure length is greater than gate valves, while fluid resistance is large, long-term operation, sealing reliability is not strong.
As one of the most important cut-off valves, the cut-off valve plays an important role in the aerospace field. As an important component of space equipment, cut-off valve realizes the function of medium conveying, cut-off and adjusting, and its sealing performance directly affects the safe and reliable operation of spaceflight equipments. The influence factors and law of sealing characteristics of typical cut-off valves are studied, and the structure design of valve seal is instructive to improve the sealing performance and reliability of valve.