When the gate valve is closed, the sealing surface can be sealed only by the medium pressure, that is, only the medium The pressure presses the sealing surface of the ram against the valve seat on the other side to ensure the sealing of the sealing surface, which is self-sealing. Most of the gate valves are forced to seal, that is, when the valve is closed, the external force is forced to press the gate to the valve seat to ensure the sealing of the sealing surface.
Movement mode: The gate of the gate valve moves linearly with the valve stem, also called the open gate valve. Usually, trapezoidal threads are provided on the lifting rod, and the rotary motion is changed into a linear motion by the nut at the top end of the valve and the guide groove on the valve body, that is, the operating torque is changed to the operating thrust. When the valve is opened, when the lifting height of the gate is equal to 1:1 times the diameter of the valve, the passage of the fluid is completely unblocked, but this position cannot be monitored during operation. In actual use, the apex of the valve stem is used as a mark, that is, the position where the valve is opened, as its fully open position. In order to consider the temperature change, the lock phenomenon is usually turned on to the apex position, and then back to 1/2-1 turn as the position of the fully open valve. Therefore, the full open position of the valve is determined according to the position of the shutter (ie, stroke). Some gate valve stem nut is set on the brake plate, and the rotation of the hand wheel drives the valve stem to rotate, so that the shutter is lifted. Rotary lever gate valve or dark rod gate valve.