The gate is a headstock ram, and motion direction of valve disc is perpendicular to the direction of the fluid, and valve can only be fully open and fully closed, can not be adjusted and the throttle. The gate valve is sealed through the valve seat and the valve disc, usually the sealing surface will surmount the metal material to increase the wear resistance, such as surfacing 1Cr13, STL6, stainless steel and so on.The disc has a rigid disc and an elastic disc. According to the difference of the disc, the gate valves are divided into rigid gate valves and elastic gate valves.
the pressure test method of gate valve
First, the disc is opened, so that the pressure inside the valve rises to the specified value. Then, close the ram, immediately remove the gate valve, check whether there is leakage on the two sides of the disc, or directly enter the test medium to the specified value on the plug of the valve cover, and check the seal on both sides of the disc. The above method is called the middle test pressure. This method is not suitable for the seal test of the gate valve under the nominal diameter of DN32mm.
Another way is to open the disc to make the valve test pressure rise to the specified value; then turn off the disc, open the blind plate at one end, and check the leakage of the seal face. Then reverse, repeat the test until qualified as above.
The sealing test at the filling and gasket of the pneumatic valve should be carried out before the seal test of the disc.