Sealing performance is one of the core indicators for measuring the quality of sanitary valves, which directly determines their applicability in high cleanliness environments. The testing process should be conducted under controlled conditions. Common testing methods include air tightness test and water pressure test. Airtightness testing usually uses dry and clean compressed air, places the valve in the closed state, and applies a specified pressure for at least 3 minutes. The pressure drop or bubble formation is observed through a pressure gauge or leak detector to determine the integrity of the main seal and valve stem seal. The test pressure is generally 1.1 times the nominal pressure, but shall not exceed the maximum allowable working pressure.

The hydrostatic test is used to verify the strength and leakage of the shell. The medium used is deionized water or clean softened water, and the test pressure is 1.5 times the nominal pressure. The pressure is stabilized for more than 10 minutes, during which no visible leakage or permanent structural deformation is allowed. For special structures such as diaphragm valves, back pressure testing is also required to simulate the sealing ability of the diaphragm under reverse pressure in actual working conditions. After the test is completed, the internal liquid should be thoroughly emptied and dried to prevent residual moisture from affecting subsequent use. All test results must be documented in a written report, recording test parameters, environmental conditions, operators, and judgment conclusions. Enterprises with a complete testing process can effectively control the quality of products leaving the factory and provide reliable guarantees for users.