Pneumatic butterfly valve is a small and light butterfly valve, which is composed of butterfly valve and pneumatic actuator. Its opening and closing are completed by the round butterfly valve rotating with the valve stem. At present, pneumatic butterfly valves are used to make large diameter in industrial systems. The valve is small in size, light in weight, simple in structure, low in cost, and labor-saving in opening and closing, so its usability is becoming more and more extensive.

Pneumatic butterfly valve device diagram
As the pneumatic butterfly valve mainly absorbs the lateral and axial displacement generated by the system, it can not only ensure the freedom of the pneumatic butterfly valve when installing, but also absorb it through the layout of the pipeline. There are two common piping methods, L-type (see Figure 2) and Z-type (see Figure 3). L-type devices are common. The overall planning is neat and beautiful, which reduces the pipeline length and fluid resistance. However, the axial stress generated by the pipeline will act on the pneumatic butterfly valve and tank nozzle, which shortens the service life of hoses and valves, and will also damage the nozzle, resulting in oil leakage. Although the Z-type device increases the pipeline length and the number of elbows, the axial displacement of the pipeline system can be absorbed by itself, reducing the axial stress on the pneumatic butterfly valve and nozzle, extending the service life, and also conducive to the stability of the pipeline system.
From the perspective of safety and service life, Z-type device is superior to L-type device, so Z-type device is preferred when the plane position allows.
Precautions for installation of pneumatic butterfly valve
(1) Before installation, the pneumatic butterfly valve must be checked, and problems found must be eliminated in time;
(2) Measures shall be taken to avoid damage to pneumatic butterfly valve during hoisting;
(3) A short receiver shall be installed behind the pneumatic butterfly valve to compensate for the deviation of the neutral size of the hose;
(4) Pneumatic butterfly valve made of steel belt mesh sleeve shall be selected as far as possible. Because of its high natural vibration frequency, which is generally 20~30Hz, much higher than 7Hz, the possibility of resonance between hose and storage tank is very small;
(5) When installing the device, do not change the pressure by force, do not hit the pneumatic butterfly valve, and do not use the method of tightening the flange bolt to eliminate the device deviation;
(6) No bracket or support shall be set on the pneumatic butterfly valve;
(7) The height of the pneumatic butterfly valve from the air or platform shall be greater than its lateral displacement compensation;
(8) The normal operation of pneumatic butterfly valve shall not be affected for the pipeline with thermal insulation and cold insulation request.