In general, industrial valves don’t have to do a strength test in use. But repaired or corroded body and bonnet should do that.

Common media used in valve pressure testing are water, oil, air, steam, nitrogen and so on. And valve pressure test methods of all kinds of industrial valves, including pneumatic, are as follows:

1.For ball valve

The pneumatic test of the ball valve should be carried out when the ball half opens.

For floating ball valve: Put the Valve in a half-open state; Infuse the valve body with test medium from one end while the other end is closed; Rotate the ball several times; Make sure the valve is closed when check the state of the closed-end. At the same time, check the sealing performance of packing and gasket, there must be no leakage. Then repeat the test from another end.

For trunnion mounted ball valve: Before the test, rotate the ball several times without any load.. Close the valve, inject the test medium from one end to the specified valve; Check the sealing performance of the leading-in end by a pressure gauge. Within the given time, it is qualified if the pressure doesn’t drop.  Then repeat the test from another end. In the end, put the valve in a half-open state, both ends closed, body filled with media, check the packing and gasket under testing pressure. Make sure no leakage happens.

2, For check valve

The axis of the lift check’s disc has to be vertical; The swing check valve's channel axis and disc axis have to be almost parallel to the horizontal line.

In strength test: inject the test medium to the specified value while another end closed. It is qualified if the valve body and cover don’t leak

In the sealing test: inject the test medium from the exit end. Check the sealing face of the entrance. It is qualified if packing and gasket have no leakage.