Pneumatic valve pressure testing principle and the matters needing attention

pneumatic valve pressure testing principle and the matters needing attention are as follows.

(1) pneumatic valve strength test (1) in general, pneumatic valve strength test, not yet repaired pneumatic valve body and valve cover or corrosion damage of pneumatic valve body and bonnet 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.
2. Pneumatic valve strength and tightness test should be done before the installation. 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.
3. Throttling pneumatic valve should not be shut down a leakage test, but should be done to strength test and packing and gasket sealing test.
2 pneumatic valve should be paid attention to in testing the strength and impermeability
(1) test, pneumatic valve installation position should be easy to check.
(2) the welding connection form of pneumatic valve, use blind flange pressure testing can be used when no taper sealing or O ring seal pressure test.
3. When the hydraulic pressure test pneumatic air valve should be ruled out as far as possible.
(4) when the test pressure should be increased gradually, don't allow a sharp, sudden pressurization.
5. 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 or equal to the mm, allowing two people close together.
6 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.
all landowners who has drive pneumatic valve, pneumatic valve to test its sealing application drive shut after sealing experiment was carried out. Rival drives, should also be manually close the pneumatic valve seal test.

(1) (3) test time and leak detection strength test and leakage test duration is commonly - min, the important and special pneumatic valve should last min. Small pneumatic valve test q can be shorter, corresponding large-diameter pneumatic valve test time can be longer accordingly. To increase the time test. 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 and high pressure pneumatic valve pneumatic valves and other important 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.
(2) has a seal on the pneumatic valve leakage test should be done to take out the packing, sealing on closed, check whether the leakage. Using gas as test, check the water in the stuffing box. Make packing sealing test, are not allowed to seal in the closed position.
3. Cast iron pneumatic valve strength test, the application of copper hammer tapping pneumatic valve, pneumatic valve cover, check for leaks. Post-processing

(4) test (1) after the strength test and leakage test in the main side 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.
2. 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 damaged.
(3) 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.