Under normal circumstances, industrial valves do not do strength tests when in use, but after repairing the valve body and valve cover or corrosion damage of the valve body and valve cover should do strength tests. For safety valves, the setting pressure and return pressure and other tests shall comply with the specifications and relevant regulations. The valve should be tested for strength and tightness before installation. Medium and high pressure valves should be checked . Valve pressure test commonly used media are water, oil, air, steam, nitrogen, etc. All kinds of industrial valves including pneumatic valves pressure test methods are as follows:

    1. Ball valve pressure test method

    The strength test of pneumatic ball valve should be carried out in the ball half open state.

(1) Floating ball valve tightness test: the valve is half open, one end is introduced into the test medium, and the other end is closed; Turn the ball several times, open the closed end when the valve is closed, and check the sealing performance of the packing and gasket, and there should be no leakage. Then introduce the test medium from the other end and repeat the above test.

(2) Fixed ball valve tightness test: before the test, the ball is turned several times without load, and the fixed ball valve is in the closed state, and the test medium is drawn from one end to the specified value; The pressure gauge is used to check the sealing performance of the inlet end. The accuracy of the pressure gauge is 0.5 ~ 1, and the measuring range is 1.5 times of the test pressure. In the specified time, no depressurization phenomenon is qualified; Then introduce the test medium from the other end and repeat the above test. Then, the valve is half open, both ends are closed, the inner cavity is filled with media, and the packing and gasket are checked under the test pressure without leakage.

(3)The three-way ball valve should be tested for tightness in various positions.

    2.Check valve pressure test method

    Check valve test state: lift type check valve disc axis is in a horizontal and vertical position; The axis of the swing check valve channel and the axis of the disc are approximately parallel to the horizontal line.

    During the strength test, the test medium is introduced to the specified value from the inlet end, the other end is closed, and the valve body and valve cover are qualified without leakage.

    The sealing test shall introduce the test medium from the outlet end, check the sealing surface at the inlet end, and the packing and gasket shall be qualified if there is no leakage.