The movement mode of gate valves

The gate plate of a gate valve moves in a straight line with the valve stem, also known as a rising stem gate valve. Usually, there is a trapezoidal thread on the lifting rod, which converts rotary motion into linear motion through the nut at the top of the valve and the guide groove on the valve body, that is, turning operating torque into operating thrust. When opening the valve, when the lifting height of the gate is equal to 1:1 times the valve diameter, the fluid channel is completely unobstructed, but this position cannot be monitored during operation. In actual use, the vertex of the valve stem is used as a marker, that is, the position that cannot be opened, as its fully open position. To consider the phenomenon of locking due to temperature changes, it is usually done by opening to the top position and then reversing 1/2 to 1 turn as the fully open valve position. Therefore, the fully open position of the valve is determined by the position (i.e. stroke) of the gate. Some gate valves have valve stem nuts installed on the gate, and the handwheel rotation drives the valve stem to rotate, thereby lifting the gate. This type of valve is called a rotary stem gate valve or a non rising stem gate valve.