The opening and closing parts of the cast steel gate valve are gate plates. The movement direction of the gate plate is perpendicular to the direction of the fluid. The gate valve can only be fully opened and closed, and cannot be adjusted or throttled. The gate has two sealing surfaces. The two sealing surfaces of the most common mode gate valve form wedges, and the wedge angle varies with the valve parameters, usually 50. When the medium temperature is not high, it is 2°52'.