Gate valve movement mode

When the gate valve is closed, the sealing surface can be sealed only by the medium pressure, that is, the sealing surface of the gate plate is pressed to the valve seat on the other side by the medium pressure only to ensure the sealing of the sealing surface. This is self-sealing. Most of the gate valve is forced seal, that is to say, when the valve is closed, the gate should be pressed to the valve seat by external force, so as to ensure the sealing surface sealing.
Movement mode: The gate of the gate valve moves in a straight line with the valve stem, which is also called a rising stem gate valve. Usually there is a trapezoidal thread on the lift rod, and through the nut on the top of the valve and the guide groove on the valve body, the rotating motion is changed into linear motion, that is, the operating torque is changed into the operating thrust. When the valve is opened, when the lift height of the gate plate is equal to 1:1 times of the valve diameter, the fluid channel is completely unobstructed, but during operation, this position cannot be monitored. In actual use, the apex of the valve stem is used as a sign, that is, the position where the valve stem does not move is taken as its fully open position. In order to consider the locking phenomenon of temperature changes, it is usually opened to the top position, and then reversed 1/2-1 turn, as the fully open valve position. Therefore, the fully open position of the valve is determined by the position of the gate plate (i.e. stroke). Some gate valve stem nuts are set on the gate plate, and the rotation of the handwheel drives the valve stem to rotate, thereby lifting the gate plate. This kind of valve is called Rotary stem gate valve or dark stem gate valve.