Valve pressure test standard principles

In order to test the quality of construction products, to prevent run, run, drip, leakage caused by a variety of accidents, before construction, we will pressure test the valve, especially the high-pressure valve, have higher requirements. In this case, then the valve pressure test when there are any standard principles? Here is a small collection of some of the principles of pressure test valve standard, as follows: (1) Under normal circumstances, the valve does not make strength test, but the valve body after repair And the valve cover or corrosion damage to the valve body and bonnet should be strength test. For safety valves, the constant pressure and back pressure and other tests should be consistent with the instructions and the relevant regulations. (2) Akira valve installation should be made for strength and tightness test. Low-pressure valve checks 20%, such as failure should be 100% of the inspection; medium and high pressure valves should be 100% inspection. (3) During the test, the installation position of the valve should be in the direction of easy inspection. (4) Valves of welded connection type may be pressure-tested with conical seal or O-ring seal when pressure test is not performed with shutters. (5) When the hydraulic test will try to exclude the valve air. (6) test pressure to be gradually increased, does not allow rapid, sudden pressure. (7) strength test and sealing test duration is generally 2 ~ 3min, important and special valve should last 5min. Small-caliber valve test time can be shorter, large-caliber valve test time may be longer. During the test, the test time may be extended if in doubt. Strength test, do not allow body and bonnet sweating or leakage phenomenon. Sealing test, the rotor pump valve only once, safety valve, high-pressure valve and other life to the valve to be carried out twice. The test, the low pressure, large diameter of the valve does not matter as well as the provisions of the valve allows leakage to allow a trace of leakage; due to universal valve, power station valves, marine valves and other valves require leakage requirements Should be implemented in accordance with the relevant provisions. (8) Throttle valves shall not be tested for the tightness of the closing parts, but shall be subjected to the strength test and the tightness test at the packing and gasket. (9) During the pressure test, the closing force of the valve only allows one person's normal physical strength to close; the force shall not be applied by means of a lever or the like (except the torque wrench); when the diameter of the hand wheel is greater than or equal to 320mm, shut down. (10) Valves with airtightness shall be taken out of packing for sealing test, checked for leaks after sealing. When testing with gas, check the water in the stuffing box. For packing sealing test, the upper seal is not allowed to be in close position. (11) Where a valve with a driving device is used, the driving device shall be used to close the valve to seal the sealing test when testing its sealing property. On the manual drive, should also be closed with the valve seal test. (12) After the strength test and the tightness test, a bypass valve fitted to the main valve shall be tested for strength and tightness at the main valve; the main valve closing member shall also be opened when it is opened. (13) cast iron valve strength test, the use of copper hammer tap valve body and bonnet, check whether there is leakage. (14) When the valve is tested, other valves shall not be allowed to be lubricated on the sealing surface unless the stopcock valve is specified to allow the sealing surface to be oiled. (15) when the valve pressure test, the blind pressure on the valve should not be too large, so as to avoid valve deformation, affecting the test results (cast iron valve too tight if pressed, but also damaged). (16) Valve pressure test is completed, the valve should be promptly ruled out water and wipe clean, should also make test records.