1. The valve shell test is a pressure test on the entire valve shell, which is composed of the valve body and valve cover. The purpose is to test the tightness of the valve body and bonnet, and the pressure resistance of the entire shell, including the connection between the valve body and bonnet. Before the shell pressure test, it is not allowed to paint the valve surface or use other coatings that can prevent leakage. When the user randomly checks the valves in stock, the existing coating will no longer be removed. The shell test requires that the shell, including the connection between the valve body and the valve cover, must not leak or suffer structural damage.

2. Shell test pressure:
1.0. For liquid medium test, the test pressure is at least 1.5 times the cold working pressure of the valve shell (1.5CWP).
2.0. Gas medium test, the test pressure is at least 1.1 times the cold working pressure of the valve shell (1.1XCWP)

1. The sealing test is a test to test the sealing performance of the opening and closing parts and the valve body sealing pair. The sealing test is divided into high-pressure liquid sealing test and low-pressure gas sealing test. Before the sealing test, except for valves sealed by grease, the oil stains on the sealing surface should be removed, but it is allowed to apply a protective agent with a viscosity no greater than that of the valve. During the test, the valve with a specified medium flow direction is pressurized according to the specified flow direction, and the check valve is pressurized from the outlet end.

2. Sealing test pressure: 1.0. The high-pressure sealing test pressure is at least 1.1 times the cold working pressure of the valve (1.1 When conducting a sealing test suitable for the cold working pressure of a valve, the test pressure shall be 1.1 times the maximum working pressure difference indicated on the valve nameplate or the design pressure difference. 2.0. Gas low-pressure test medium, the test pressure is 0.6 MPa±0.1 MPa; when the nominal pressure of the valve is less than PN6, the test pressure is 1.1 times the cold working pressure of the valve (1.1XCWP).

1. Cold working pressure (CWP), the maximum allowable working pressure of the valve shell at an operating temperature of -20 degree ~ 38 degree .
2. Test pressure: test pressure, the gauge pressure of the test medium that the valve inner cavity bears during the test.
3. Test medium: test fluid. During the test, a liquid or gas is filled into the valve cavity and exerts a certain pressure.
4. Design differential pressure: when the valve is in the closed position, the maximum allowable pressure difference between the medium at the inlet and outlet. (The design pressure difference of some structural valves may be less than the cold working pressure.)
5. Elastic sealing pairs: resilient seats, sealing pairs composed of non-metallic elastic materials, solid and semi-solid greases, etc.
6. Double block-and-bleed valve is a valve with two independent sealing pairs. When the valve is in the closed position, the medium in the body cavity between the two sealing pairs is contained when the cavity pressure is released. , two sealing pairs can cut off the seal at the same time.
7. Shell test Shell test is a test conducted on the valve shell according to the specified test medium and test pressure. (Including the opening and closing drive mechanism that is affected by the medium pressure of the valve itself and connected to the internal components of the valve.)
8. Closure test: a test on the sealing performance of the valve opening and closing parts sealing pair according to the specified test medium and test pressure.
9. Back seal test is a test on the sealing performance of the upper seal structure of the valve according to the specified test medium and test pressure.

The test pressure is at least 1.1 times the cold working pressure of the valve (1.1XCWP).
Note: 1. Except for valves with bellows stem sealing structures, all valves with upper sealing structures should undergo upper sealing tests.
2. Oil-sealed plug valves should undergo a high-pressure sealing test, and the low-pressure sealing test is "optional." The sealing grease is allowed to be retained during the test; double cut-off and discharge valves should undergo a high-pressure sealing test, and the low-pressure sealing test is optional.
3. After the high-pressure sealing test of some valves with elastic sealing structures, their sealing performance under low-pressure conditions may be reduced, but such structures should be able to pass this test to prove the compliance of the valve structure.