The pneumatic butterfly valve is composed of a pneumatic actuator and a butterfly valve. The pneumatic butterfly valve is opened and closed with the circular butterfly plate rotating with the valve, in order to realize the use of the pneumatic valve is mainly used as a cut-off valve, and it can also be designed to have the function of regulating or segment valve and regulating. At present, the butterfly valve is used more and more in low pressure large and medium diameter pipelines.

    1. The working principle of pneumatic butterfly valve
The butterfly plate of the butterfly valve is installed in the diameter direction of the pipe. In the cylindrical channel of the butterfly valve body, the disc disc rotates around the axis, the rotation Angle is between 0°-90°, and the valve is fully open when it is rotated to 90°. The butterfly valve is simple in structure, small in size, light in weight, and consists of only a few parts. And only need to rotate 90° can be quickly opened and closed, simple operation, and the valve has good fluid control characteristics. When the butterfly valve is in the fully open position, the thickness of the butterfly plate is the only resistance when the medium flows through the valve body, so the pressure drop generated by the valve is small, so it has better flow control characteristics. Butterfly valves have two types of seal: bullet seal and metal seal. Elastomeric sealing valve, the sealing ring can be mounted on the valve body or attached to the periphery of the disc.

    2. Pneumatic butterfly valve maintenance and commissioning

    2.1 Check and maintain solenoid valve and silencer
Check and maintain the solenoid valve every 6 months, mainly to check whether the solenoid valve has dirty things blocked the spool activity is free, whether the silencer is blocked by dirty things and whether it is smooth. Whether the air source is clean and without moisture.

    2.2 Cylinder inspection and maintenance plan

    Usually clean the cylinder surface and refuel the cylinder rotating shaft circlip, and open the cylinder end cover regularly every 6 months to check whether there is debris and water in the cylinder, as well as the state of grease. If the grease is missing or has dried, the cylinder needs to be disassembled for comprehensive maintenance and cleaning before adding grease.

    2.3 Valve Body Check
Every 6 months, check whether the appearance of the valve body is good, whether the installation flange is leaked, if it is convenient to check whether the valve body seal is good, no wear, and whether the valve plate is flexible, and whether the valve is stuck.

    2.4 Cylinder block disassembly and assembly methods and precautions

    First of all, the cylinder is removed from the valve body, first the cylinder two end cover open, remove the piston must pay attention to the direction of the piston rack, and then rotate the cylinder shaft clockwise with an external force to make the piston run to the outside, and then close the valve hole slowly ventilation with pressure gently top out of the piston, but this method must pay attention to slowly ventilation, otherwise the piston will suddenly eject, a little dangerous! Then remove the circlip on the cylinder shaft, and the cylinder shaft can be taken out from the other end. Then each component can be cleaned and greased. The parts that need to be greased are: the inner wall of the cylinder and the piston seal ring, the rack and the back ring, and the gear shaft and the seal ring. After the grease is added, it is necessary to install in reverse order according to the order and parts of the disassembly. It is necessary to install in reverse order according to the order and parts of the disassembly. It is necessary to pay attention to the position of the gear rack and ensure that the upper slot of the gear shaft is parallel to the cylinder block when the piston is reduced to the innermost position when the valve is opened, and the upper slot of the gear shaft is perpendicular to the cylinder block when the piston is extended to the outer position.

    2.5 Cylinder and valve body installation and commissioning methods and precautions

    First put the valve in the closed state with external force, first put the valve in the closed state with external force, that is, rotate the valve shaft clockwise until the valve plate is in contact with the valve seat seal, and at the same time put the cylinder in the closed state (that is, the small slot above the cylinder shaft is vertical with the cylinder block for the valve that is turned clockwise). Then install the cylinder on the valve (the installation direction can be parallel to the valve body or vertical), and then see whether the screw hole is correct, there will not be too much deviation, if there is a little deviation, turn the cylinder block a little, and then tighten the screw. Pneumatic butterfly valve debugging first check whether the valve accessories are fully installed, solenoid valve and silencer, etc., if there is not complete, can not be debugging, the normal gas pressure of the supplier is 0.6MPA±0.05MPA, before operation to ensure that there is no debris in the valve body stuck in the valve plate, the manual operation of the solenoid valve manual button (manual operation when the solenoid coil is lost power, manual operation is effective; When the electric control operation, the manual twist is set to the 0 position circle to lose power, and the manual operation is effective; Position 0 is to close the valve, position 1 is to open the valve, and then the electric opening valve is obtained. If the electric closing valve is needed, the solenoid valve coil can be rotated 180 degrees to close the valve), and observe the operating state of the valve. If the valve is found to be very slow in the starting position of opening the valve during debugging operation, but as long as it is soon after the action, the valve is found to be very slow in the starting position of opening the valve during trial operation, but as long as it is soon after the action, this situation is that the valve is closed too tight, just adjust the cylinder stroke a little bit smaller (adjust the stroke adjustment screws at both ends of the cylinder at the same time). When adjusting, it is necessary to run the valve to the open position, and then turn off the air source and adjust it), and adjust it until the valve is easily opened and closed in place without leakage. If the silencer is adjustable, the valve switching speed can be adjusted. It is necessary to adjust the silencer to the valve switching speed. If the adjustment is too small, the valve may not operate.