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 is pressed to the other side of the valve seat to ensure the seal of the sealing surface, which is the seal.
Most of the gate valve is a forced seal, that is, the valve closed, to rely on external forces to force the gate pressure to the seat to ensure the sealing surface of the seal. Movement mode: Gate valve of the gate with the valve stem for linear movement, also known as the Ming-stem gate valve. Usually on the lifter has trapezoidal thread, through the top of the valve nut and valve body on the guide groove, the rotation of the movement into a straight line movement, that is, the operation torque into operation Thrust. When opening the valve, when the gate lifting height equals valve diameter 1:1 time times, the fluid channel is completely unimpeded, but at run time, this position is unable to monitor. In actual use, it is the vertex of the stem as a sign, that is, the position of the open, as its full opening position. In order to consider the temperature changes in the deadlock phenomenon, usually open to the vertex position, and then back to the 1/2-1 ring, as the position of full opening valve. Therefore, the full open position of the valve, according to the position of the gate (that is, itinerary) to determine. Some gate valve stem nut is located on the gate, the handwheel rotates to drive the stem to rotate, and causes the gate to ascend, this kind of valve is called the Rotary Pole Gate valve or is called the Dark pole gate valve.