Working principle and failure analysis of pneumatic valve
1 Working principle of pneumatic valve
The so-called pneumatic valve specifically refers to the use of the cylinder as the actuator and the compressed air as the power source to drive the valve to adjust the switch. When the regulating pipeline receives the control signal sent by the automatic control system, it will adjust related parameters such as temperature, pressure and flow. In general, pneumatic valves are characterized by reliability, fast response, and simple control. In the specific operation process, after the signal pressure of 0.02-0.10MPa is input into the regulating air chamber, the film will generate thrust. During the downward movement of the thrust plate, the spring is compressed, thereby realizing 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 the research and analysis of the fault status of pneumatic valves, it is learned that the possible faults include valve blockage, valve not working, valve leakage, impact, etc. Therefore, it is necessary to formulate countermeasures according to actual faults to achieve system stability and the company's operation has created higher benefits. .
2.1 Pneumatic valve stuck
If the valve stem moves slowly, 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. In this case, the valve or auxiliary pipeline should be switched on and off quickly to flush away the medium blocking the valve. At the same time, the valve stem can be clamped with a pipe wrench, and the signal pressure can be applied to rotate the valve stem against the reaction force. If the above problems still cannot be solved, the driving power can be increased to perform repeated up and down movements. It should be noted that because the above operations are highly professional, when solving and handling this fault, it needs to be completed with the help of professionals.
2.2 Valve does not work
For this kind of failure, it is first necessary to judge whether the air source pressure is normal, and on this basis, find the air source failure. When the air source pressure in the valve is normal, it is necessary to judge whether the amplifier of the electric/pneumatic converter has output. When there is no output, there may be two situations: First, the water in the air is compressed and placed at the power amplifier ball valve; second, the constant current hole of the amplifier is blocked. In this regard, it is necessary to implement various methods such as cleaning the gas source, removing debris, and dredging constant holes. If the valve still does not move after the above treatment, it is necessary to disassemble the valve and conduct a comprehensive inspection.