The airtightness of pneumatic ball valves requires that the airtightness index of pneumatic ball valves shall be determined by the requirements for internal leakage and external leakage. The national standard stipulates that the airtightness of non-metallic sealed pneumatic ball valves shall comply with the requirements of GB/T13927 Pressure Test for General Purpose Valves.; No visible leakage during the test duration;; Aerospace industry standards stipulate pneumatic ball valves for ground gas pipeline systems.; Under the air pressure of 0.05MPa and 1.1 times of the nominal pressure, hold the pressure for 3min, and the internal leakage rate shall not be greater than 3 10-5Pa m3/s (no bubbles escape); Under the air pressure condition of 1.1 times of the nominal pressure, maintain the pressure for 3min, and the external leakage rate shall not be greater than 1 10-5 Pa m3/s (no bubbles escape).

Inspection process and main uses of stainless steel pneumatic butterfly valve
Inspection process of stainless steel pneumatic butterfly valve:
1. The non explosion proof area shall be selected as the testing site, and the testing work must be stopped under the premise of safety. After the testing, the person in charge shall make account records; 2. Test at least once a year;
3. Empty the hose, clean it, and check whether the connectors at both ends can conduct electricity; 4. For the hose with non-conductive connectors at both ends, the detection will not be stopped.
5. Place the pneumatic butterfly valve vertically and horizontally on the support or roller bed to ensure that the hose can be moved under pressure; 6. Close the end of the hose, fill the hose with water, and empty the air in the hose; 7. Pressurize to 1.5 times of the design pressure for more than ten minutes, check whether there is leakage, and check whether the connectors at both ends of the pneumatic butterfly valve can be energized under pressure; 8. Release the pressure and discharge the liquid in the pneumatic butterfly valve clean;
9. After the test, re test the conductivity of the pneumatic butterfly valve.
10. Under pressure, the elongation of pneumatic butterfly valve is much longer than that of rubber hose, which is normal.