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The standards and specifications for valve pressure testing are as follows:

1. Under normal circumstances, the valve is not tested for strength, but the strength test should be carried out after repairing the valve body and bonnet or the body and bonnet damaged by corrosion. For safety valves, their constant pressure and seat pressure and other tests shall comply with the provisions of their instructions and relevant regulations.

2. The strength and tightness test of valve installation should be done. 20% spot check of low-pressure valve, if unqualified, it should be inspected; Medium and high pressure valves should be inspected.

3. During the test, the valve installation position should be in the direction that is easy to check.

4. The valve in the form of welded connection can be tested with a conical seal or O-ring seal when the pressure test with the rib plate is not possible.

5. During the hydraulic test, the valve air will be eliminated as much as possible.

6. The pressure should gradually increase during the test, and it is not allowed to increase the pressure sharply and suddenly.

7. The duration of strength test and tightness test is generally 2~3min, and important and special valves should last 5min. The test time of small-diameter valves can be correspondingly shorter, and the test time of large-diameter valves can be correspondingly longer. During the test, the test time can be extended if in doubt. During the strength test, sweating or leakage of the valve body and bonnet is not allowed.

8. The throttle valve is not tested for the tightness of the closing parts, but should be tested for strength and the tightness test at the packing and gasket.

9. In the pressure test, the valve closing force only allows a person's normal physical strength to close; Do not use tools such as levers to apply force (except torque wrenches), when the diameter of the handwheel is greater than 320mm, two people are allowed to close together.

10. The valve with upper seal should take out the packing for tightness test, and check whether there is leakage after the upper seal is closed. When using gas for testing, water is filled in the stuffing box for inspection. When packing tightness test, the upper seal is not allowed to be in a tight position.

11. Where the valve has a driving device, when testing its tightness, the driving device should be used to close the valve for tightness test. For manual drive devices, a sealing test should also be carried out to close the valve with a movement.

12. The bypass valve installed on the main valve after the strength test and tightness test, and the strength and tightness test is carried out in the main valve; When the main valve shut-off is opened, it should also be opened.

13. During the strength test of cast iron valve, copper hammer should be used to tap the valve body and valve cover to check whether there is leakage.

14. When the valve is tested, except for the plug valve that allows the sealing surface to be oiled, other valves are not allowed to be oiled on the sealing surface.

15. When the valve is tested for pressure, the pressing force of the blind plate on the valve should not be too large, so as to avoid deformation of the valve and affect the test effect (if the cast iron valve is pressed too tightly, it will be damaged).

16. After the valve pressure test is completed, the water in the valve should be removed in time and wiped clean, and the test record should also be made.