The Testing Principle and Procedure of Sanitary Check Valve

1, under normal circumstances, the new check valve will not be tested for strength, but after the repair of the valve body, the valve body and bonnet must undergo strength testing.
2, the check valve can be installed for strength and sealing test. First check 20%, if not 100% of the inspection; the high-pressure valve should be 100% inspected.
3,during the test, the check valve installation location should be easy to check the direction.
4, welded connection form of the check valve, the blind plate test pressure can not be used when the cone seal or O-ring seal test pressure.
5, the hydraulic test will try to exclude the check valve air.

6, the test pressure gradually increased, does not allow sharp, suddenly pressurized.

7, strength test and sealing type test duration is generally 2 ~ 3min, important and special check valve should be continued for 5min. Small diameter check valve test time can be shortened accordingly, large diameter check valve test time can be longer. In the course of the test, if in doubt extend the test time. Strength test, do not allow the body and the valve cover appears sweating or leakage. Seal test, the rotor pump check valve is only carried out once, safety valve, high pressure valve and other students need to be carried out twice the valve. The test, the low-pressure, large-caliber non-essential check valve and the provisions of the allowable leakage of the check valve, allowing a small amount of leakage; due to different requirements of the general check valve, power station valves, marine valves and other check valves , the leakage requirements should be implemented in accordance with the relevant provisions.
8, the throttle valve is not closed pieces of sealing test, but should be strength tests and packing and gasket sealing test.
9, test pressure, the check valve closing force allows only one person’s normal physical strength to close; not use tools such as leverage afterburner.
10, the seal on the check valve should be removed for packing sealing test, the official seal on the seal, check whether the leakage. When using gas for testing, fill in the stuffing box filled with water. Do not allow the upper seal to be in the closed position for the packing tightness test.
11, for the check valve, test its sealing application of the drive device, to close the valve when the line tightness is tested. The manual drive device, should also be used to close the valve sealing test.
12, the main valve is installed on the bypass valve for the main valve strength and sealing test; main valve should also be opened.
13, cast iron valve strength test, the application of copper hammer tapping body and bonnet to check for leakage.
14, check valve for testing, in addition to the provisions of the plug valve to allow sealing surface oiled, the other check valve does not allow oil in the sealing surface test.
15, sanitary check valve pressure test, the blind on the check valve of the clamping force should not be too large, so as to avoid deformation of the check valve, affecting the test results.

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