Working principle for API gate valve

When the API gate valve closed, the valve can seal up rely on external force or rely on the medium pressure to seal, that is to rely on medium pressure to the gate sealing surface pressure to the other side of the seat to ensure the sealing surface seal, which is self sealing. Most of the valve is forced seal, that is, when the valve closes, to rely on external force to force the gate to the seat, in order to ensure the sealing surface sealing. The gate of the gate valve works in a straight line with the stem, called the lift bar gate valve (also known as the bar gate valve). Usually there is a trapezoidal thread on the lifter. The rotating motion is changed into a straight line through the nut at the top of the valve and the guide groove on the valve body. That is to say, the operating torque is changed into the operating thrust. When opening the valve, when the gate lift height is equal to 1:1 times of the valve path, the passage of the fluid is completely unblocked, but at run time, this position is unable to monitor. In actual use, the top of the stem is used as a sign, i.e., 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 opening position of the valve is determined by the position of the gate.