1 Working principle of pneumatic valve
The so-called pneumatic valve specifically refers to the use of a cylinder as an actuator and compressed air as a power source to drive the valve to adjust the switch. When the regulating pipeline receives the control signal sent by the automation control system, it will adjust the temperature, pressure, flow and other related parameters. In general, the characteristics of pneumatic valves are reliability, fast response, and simple control. In the process of specific operation, after inputting the signal pressure of 0.02-0.10MPa to the regulating air chamber, the thin film will have thrust force. During the downward movement of the thrust plate, the spring will be compressed to realize the valve stem, push rod and valve core. Move down to achieve the purpose of adjusting the valve.
 

2 Common faults and treatment methods of pneumatic valves
After researching and analyzing the failure status of pneumatic valves, it is understood that possible failures include valve blockage, valve non-operation, valve leakage, and shock, etc. Therefore, it is necessary to formulate countermeasures based on actual failures to achieve system stability The operation of the company creates higher benefits.
 

2.1 Pneumatic valve jam
If the action of the valve stem is sluggish, it means that there may be more viscous substances in the valve body, and the blockage of the pneumatic valve mainly occurs in the early stage of system operation. When encountering this situation, the valve or auxiliary line should be quickly switched on and off to flush away the medium blocking the valve. At the same time, a pipe wrench can be used to clamp the valve stem and apply signal pressure to rotate the valve stem in a counter-force. If the above problems still cannot be solved, then the drive power can be increased to perform repeated up and down movements. It should be noted that, because the above operations are highly professional, it is necessary to complete with the help of professionals when solving and handling this fault.
 

2.2 Valve does not operate
For this fault, the first step is to determine whether the air source pressure is normal, and on this basis to find the air source fault. When the pressure of the gas source in the valve is normal, it is necessary to judge whether the amplifier of the electric/gas converter has an output. When there is no output, there may be two situations: First, the water in the air is compressed and placed at the amplifier ball valve; second, the amplifier's constant orifice is blocked. In this regard, it is necessary to implement various methods such as cleaning the air source, removing debris, and dredging the constant orifice. If the valve still has no action after the above treatment, the valve needs to be disassembled and a comprehensive inspection should be performed.