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(1) Generally, strength test shall not be conducted for the valve, but strength test shall be conducted for the repaired valve body and bonnet or the valve body and bonnet damaged by corrosion. For safety valve, its constant pressure, reseating pressure and other tests shall conform to the specifications and relevant regulations.

(2) strength and sealing test shall be conducted for the valve installation. Spot check ? 20% for low-pressure valves, and ? 100% ? for unqualified valves, and ? 100% ? for medium and high-pressure valves. A kind of

(3) during the test, the valve shall be installed in the direction easy for inspection.

(4) for valves with welded connection, if the blind plate pressure test fails, the conical seal or ? o ? ring seal can be used for pressure test. A kind of

(5) during the hydraulic test, the valve air shall be removed as much as possible.

(6) during the test, the pressure shall be increased gradually, and it is not allowed to increase sharply and suddenly.

(7) the duration of strength test and sealing type test is generally ? 2 ~ 3min, and important and special valves shall last ? 5min. The test time of small diameter valve can be shorter, and that of large diameter valve can be longer. During the test, if there is any doubt, the test time can be extended. During the strength test, no sweat or leakage is allowed on the valve body and bonnet. Generally, the sealing test can only be conducted once for valves, and twice for safety valves, high-pressure valves, etc. During the test, slight leakage is allowed for low-pressure and large-diameter unimportant valves as well as valves with leakage allowed by regulations; due to different requirements for general valves, power station valves, marine valves and other valves, leakage shall be carried out according to relevant regulations.

(8) after the completion of the valve pressure test, the accumulated water in the valve shall be removed in time and wiped clean, and the pressure test record shall be made.