Gate valve is an on-off type valve. The movement direction of the gate plate is perpendicular to the direction of the fluid. The gate valve can only be fully opened and fully closed, and cannot be adjusted and throttled. The gate valve is sealed by the contact of the valve seat and the gate plate. Usually, the sealing surface will be welded with metal materials to increase wear resistance, such as 1Cr13, STL6, stainless steel, etc. The gate has a rigid gate and an elastic gate. According to the different gates, the gate valve is divided into a rigid gate valve and an elastic gate valve.