Stop valve, also known as shut-off valve, is one of the widely used valves. It is popular because the friction between the sealing surfaces is small during the opening and closing process, which is relatively durable, the opening height is not high, easy to manufacture and easy to maintain. It is not only suitable for medium and low pressure, but also suitable for high pressure. The closing principle of the stop valve is to make the sealing surface of the valve disc and the sealing surface of the valve seat closely fit with the pressure of the valve rod to prevent the medium from flowing. The "three chemical supplies" of valves in China once stipulated that the flow direction of stop valves shall be from top to bottom, so there is directionality during installation. The structural length of the stop valve is longer than that of the gate valve, and the fluid resistance is large. The sealing reliability is not strong during long-term operation.

As one of the important block valves, globe valves play an important role in the field of Dalian marine valves. As an important component of marine equipment, stop valve realizes the functions of medium transmission, stop and regulation. Its sealing performance directly affects the safe and reliable operation of marine equipment. The research on the influencing factors and laws of the sealing characteristics of typical stop valves is of guiding significance to the structural design of the valve sealing pair, so as to improve the sealing performance and reliability of the valve.