The open and closed parts of non-rising stem flexible gate valve are gates. The direction of movement of the gate is perpendicular to the direction of the flow. The gate valve can only be fully opened and fully closed and cannot be adjusted or throttled. The gate has two sealing surfaces. The two sealing surfaces of the most commonly used mode gate valves form a wedge, and the wedge angle varies with the valve parameters, typically 50, and 2°52”” when the medium temperature is not high. Wedge gate valve gate can be made into a whole, called the rigid gate; can also be made of a slight deformation of the gate, in order to improve its craft, make up for the deviation of the sealing surface angle in the process, this kind of brake The plates are called flexible gates and are generally flanged.
The flexible wedge type gate valve is also called a lift rod gate valve (also called a stem gate valve). Trapezoidal threads are usually provided on the lifting rods. The nuts on the top of the valve and the guide grooves on the valve body convert the rotation into a linear motion, that is, the operating torque becomes the operating thrust. When the valve is opened, when the lifting height of the gate is equal to 1:1 of the valve diameter, the channel of the fluid is completely open, but this position cannot be monitored during operation. In actual use, the vertex of the valve stem is used as a mark, that is, a position that does not move, as its fully open position. In order to consider the phenomenon of lock-up temperature change, usually in the open to the top position, and then rewind 1/2-1 lap, as a fully open valve position. Therefore, the fully open position of the valve is determined by the position of the gate (ie stroke).