The working principle of a gate valve

A gate valve is a valve with a gate. The gate moves perpendicular to the flow direction. Gate valves can only be fully opened or closed; they cannot regulate or throttle flow. The gate valve seals via contact between the gate and the seat. Typically, metal materials are overlaid on the sealing surface to improve wear resistance, such as overlay welding with 1cr13, STL6, or stainless steel. Gates can be rigid or flexible. Based on the gate type, gate valves are classified as rigid gate valves and flexible gate valves.

When the gate valve's closing member is a gate, the gate moves perpendicular to the fluid's direction. The gate valve can only be fully opened or closed; it cannot regulate or throttle flow. The gate has two sealing surfaces; more commonly, the two sealing surfaces form a wedge. The wedge angle varies depending on the valve parameters, typically 5°, or 2°52' when the medium temperature is not high. The wedge gate's gate can be a single piece (rigid gate) or designed for slight deformation to improve workability and compensate for deviations in the sealing surface angle during processing (flexible gate). When the gate valve is closed, the sealing surface relies solely on medium pressure for sealing; that is, the medium pressure presses the gate's sealing surface against the valve seat on the other side to ensure sealing (self-sealing). Most gate valves are force-sealed; that is, when the valve is closed, external force must press the gate against the valve seat to ensure sealing. When the top thread of the gate valve moves with the trapezoidal thread, it is also called the movement position of the gate stem in the fluid. To account for temperature-related locking, the valve is usually opened to the top and then returned 1/2-1 turn to the fully open position. Therefore, the fully open position of the valve is determined by the gate's position or stroke. In some gate valves, the stem nut is located on the gate. The handwheel rotates to drive the stem to rotate and lift the gate. This type of valve is called a rotary stem gate valve or a rising stem gate valve.