The strength test of the gate valve is the same as that of the globe valve. There are two methods for the tightness test of the gate valve.
Open the gate to make the pressure in the valve rise to the specified value; then close the gate, take out the gate valve immediately, check Mixing Valves suppliers
whether there is leakage at the seals on both sides of the gate, or directly inject the test medium into the plug on the valve cover to the specified value, Check the seals on both sides of the gate. The above method is called intermediate pressure test. This method should not be used for sealing tests on gate valves with a nominal diameter below DN32mm.
Another method is to open the gate to make the valve test pressure rise to the specified value; then close the gate, open one end of the blind plate, and check whether the sealing surface is leaking. Then turn back and repeat the above test until it is qualified.
The tightness test of the packing and gasket of the pneumatic gate valve shall be carried out before the tightness test of the gate.
Pressure test method of safety valve
The strength test of the safety valve is the same as other valves, which is tested with water. When testing the lower part of the valve body, the pressure is introduced from the inlet I=I end, and the sealing surface is closed; when testing the upper part of the valve body and the bonnet, the pressure is introduced from the outlet El end, and the other ends are closed. If the valve body and bonnet have no leakage within the specified time, it is qualified.
For sealing test and constant pressure test, the general use medium is: the safety valve for steam uses saturated steam as the test medium; the valve for ammonia or other gases uses air as the test medium; the valve for water and other non-corrosive liquids uses water as the test medium . Nitrogen is often used as the test medium for safety valves in some important positions.
The sealing test is carried out with the nominal pressure value as the test pressure, and the number of times is not less than twice, and no leakage within the specified time is qualified. There are two leak detection methods: one is to seal the joints of the safety valve, and use butter to seal the tissue paper on the flange. The plastic plate or other plate is sealed on the lower part of the outlet flange, and the valve disc is sealed by filling with water, and it is qualified if the water does not bubble. The number of constant pressure and reseating pressure tests of the safety valve is not less than 3 times, and compliance with the regulations is qualified.
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