Pneumatic valve pressure testing principle and the matters needing attention

( In general, pneumatic valve does not make the strength test, but after the repair corrosion damage of pneumatic valve and pneumatic valve cover or pneumatic valve and pneumatic valve cover strength test should be done. For safety pneumatic valve, the constant pressure and back pressure, and other test shall comply with the terms of the instruction and the relevant regulations. ( Pneumatic valve installation of akira strength and tightness test should be done. Low pressure pneumatic valve % selectiving examination, such as unqualified shall be % of the check; Medium and high pressure pneumatic valves shall be % of the inspection. ( Test, pneumatic valve installation position should be easy to check. ( Welding connection in the form of a pneumatic valve, use/board test can be used when no taper sealing or O ring seal pressure test. ( When the hydraulic pressure test will be pneumatic valve air out as far as possible. ( When test pressure is gradually increased, don't allow a sharp, sudden pressurization. ( Strength test and sealing test duration is commonly - min, the important and special pneumatic valve should last min. Small test time can be short some corresponding pneumatic valve, pneumatic valve test of large diameter time can be longer accordingly. In the process of test, if in doubt can prolong the test of time. Strength test, do not allow the pneumatic valve and pneumatic valve cover appear sweat or leakage phenomenon. Leakage test, generally only a pneumatic valve, pneumatic valve safety, such as high pressure pneumatic valve to pneumatic valves require twice. Test, the low pressure, large diameter pneumatic valve is not important, and have permitted leakage of pneumatic valves, allowed to have traces of leakage phenomenon; Because general pneumatic valve, power station with pneumatic valve pneumatic valves, pneumatic valves, and other requirements vary, the leakage requirements shall be in accordance with relevant provisions. ( Throttling pneumatic valve should not be shut down a leakage test, but should be done to strength test and packing and gasket sealing test. ( Pressure testing, pneumatic valve closing force only allow a person's normal physical strength to close; Shall not be leveraged tools such as strength, In addition to the torque wrench) , when the handwheel diameter greater than to wait until in mm, allowing two people close together. ( Has a seal on the pneumatic valve leakage test should be done to take out the packing, the seal officer, after check whether leakage. Using gas as test, check the water in the stuffing box. Make packing sealing test, are not allowed to seal in the close position. ( Whoever has the drive pneumatic valve, pneumatic valve to test its sealing application drive close antagonism for leakage test. Rival drive, also should undertake with dynamic close the pneumatic valve seal test. ( After the strength test and leakage test in the main by ventilation of pneumatic valve, valve, pneumatic valve in the main strength and tightness test; Pneumatic valve shut down a main opens, should also be open. ( Cast iron pneumatic valve strength test, the application of copper hammer tapping pneumatic valve body and valve cover, check for leaks. ( Pneumatic valve test, in addition to cock pneumatic valve has a regulation to allow oil sealing surface besmear outside, other pneumatic valves do not allow the coating on the surface of the sealing oil test. ( Pneumatic valve pressure testing, blind threatening the pressure force of pneumatic valves and shoulds not be too big, lest pneumatic valve deformation, affect test result ( Cast iron is too tight, the pneumatic valve if will damage) 。 ( Pneumatic valve after pressure testing, should be promptly eliminate water accumulation in the pneumatic valve and clean, also should make a good record of test.