Installation and maintenance of pneumatic ball valve
(1) Before the pneumatic ball valve is installed and used, the pneumatic ball valve must be inspected before installation and tested for opening and closing operation. It can be installed and used only when the operation is normal.
(2) The installation and maintenance of pneumatic pneumatic ball valve shall make the valve concentric with the pipeline flange as far as possible, and shall be supported and fixed. The pneumatic ball valve shall not be subject to other external forces to avoid damage to the middle seal of the valve and deformation of the valve. The valve can not be used due to inflexible opening and closing and damage of the valve.
(3) Ensure that the power air supply provided by the pneumatic ball valve and pneumatic components must be clean and free from oil and water as far as possible. The cleanliness shall be less than 0.4 microns.
(4) Before connecting to the air source, the air supply pipeline, air source interface, switch and other devices must be cleaned to prevent the failure caused by the dirt and sediment washed into the pneumatic execution unit due to the uncleanness of the pipeline.
(5) The connection of pneumatic actuator, solenoid valve, positioner, filter, pressure reducing valve, etc. can be made of copper pipe or nylon pipe. To prevent dust and reduce noise, the exhaust port should be installed with silencer or silencing throttle valve.
(6) After installation, the pneumatic valve shall be tested, and the pneumatic actuator shall be pressurized to the rated value with the pressure of 0.4~0.7 mpa. The pneumatic ball valve shall be tested for opening and closing, and the opening and closing of the valve shall be observed. It shall rotate flexibly without jamming. If the switch is jammed, the air pressure can be increased. Repeatedly open and close the valve to make it flexible.
(7) When installing and debugging the on-off pneumatic ball valve, first use the manual device (the manual button on the solenoid valve) for debugging, and then conduct the power on debugging after the action is normal.
(8) The pneumatic pneumatic ball valve shall be regularly maintained at the rotating part of the valve stem, and the oil (engine oil) shall be added once every three months. Regularly drain and blow down the pneumatic actuating unit and the air filter used together. Under normal circumstances, it shall be inspected once every six months and overhauled once a year.

3. Problems existing in the opening and closing process of pneumatic butterfly valve and solutions:
The butterfly valve has a diameter of 1.75m and is operated by two hydraulic ring servomotors. Since the piston of the hydraulic ring servomotor is rigidly connected with the action arm, a seal is set between the piston and the cylinder body, and the main function of the seal is to prevent the pressure oil in the oil chamber from leaking. During operation, the piston of the hydraulic ring servomotor rotates in the cylinder body under the action of the pressure oil, thus driving the spindle to rotate to open and close the valve. In the process of use, the hydraulic ring servomotor often has some problems when operating the butterfly valve valve, which makes the valve can not be opened or closed normally all the time. The valve can be opened or closed once for several minutes or more than ten minutes, sometimes it can not be opened or closed at all, which seriously threatens the safe and stable operation of the unit. Through inspection, it was found that the main reason was that the eccentric wear between the piston and the annular cylinder was serious, and the gap at the corresponding diameter of the eccentric wear point was large. This not only causes great resistance to the piston movement, but also releases a large amount of oil pressure at the clearance. The main shaft and valve are not stressed enough to cause the butterfly valve to be blocked when opening and closing. The main reason is that the relative position error between the annular cylinder block and the butterfly valve spindle is too large, resulting in serious damage to the piston.
In the process of reforming the butterfly valve hydraulic ring servomotor, it is mainly to change the connection form between the action arm and the piston from rigid connection to elastic connection, so that the piston can automatically generate radial displacement when moving along the ring cylinder body, which can drive the action arm to not be limited by its rigidity, and can automatically adjust the misalignment tolerance in manufacturing and installation, The working performance of the hydraulic ring servomotor is improved, and satisfactory results are obtained.
Due to the limitation of machining, the thrust plate on the piston is mainly machined. Fit the thrust disc with the shaft and hole of the action arm from the original transitional fit to the dynamic fit to ensure that the radial displacement of the thrust disc is greater than or equal to 2mm, and still use the six M16 screw holes at the end of the action arm shaft to increase the connection between the thrust disc and the action arm; Bolt 2 at 20 points and hole Φ The fit clearance of 30 shall be less than 2.5 mm, and the axial clearance shall be 0.05~0.1 mm, so as to ensure that the radial movement of the piston is not hindered, and the axial displacement can be controlled. The sealing cover plate 1 and the sealing gasket 3 are compressed by screws and thrust discs to form a sealing device.