Gate valve closed, the sealing surface can only rely on media pressure to seal, that is only rely on media pressure to seal the gate face pressure to the other side of the seat to ensure the sealing surface of the seal, which is self sealing. Most of the valve is forced to seal, that is, when the valve is closed, to rely on external force to force the gate to the seat, in order to ensure the sealing surface of the seal.

Gate valve together with the stem for the straight movement, called the lift rod gate valve (also known as the gate valve). Usually on the lifting rod with trapezoidal thread, through the valve on the top of the nut and the body of the guide slot, the rotating motion into a linear motion, that is, the operating torque into the operating thrust.

When the valve is opened, when the gate height is equal to 1:1 times the diameter of the valve, the fluid passage is completely free, but at the time of operation, the position can not be monitored. Actual use, is the apex of the stem as a sign, that is, the open position, as its fully open position. Temperature changes appear to consider locking phenomenon, usually open to the vertex position, and then rewind 1/2 1 circle, as a fully open valve position. Therefore, the valve fully open position, according to the location of the gate (that is, the stroke.

Some gate valve, the valve stem nut is located in the gate, the hand wheel rotation to drive the valve stem rotation, and so that the gate to upgrade, this valve is called the rotating rod gate valve or called the dark bar gate valve.

Turn the hand wheel, through the hand wheel and the stem of the inlet and exit, enhance or decrease the valve plate connected with the stem, to achieve the role of opening and closing