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).

In addition, the pneumatic butterfly valve is small and light, easy to disassemble and repair, and can be installed at any position. Simple and compact structure, small operating torque, and quick 90 ° rotation opening. The flow characteristics tend to be straight, and the regulation performance is good. The connection between the butterfly plate and the valve rod adopts a pin free structure, which overcomes the possible internal leakage point.