How to perform routine maintenance on pneumatic control valves
Daily maintenance of pneumatic regulating valve and pneumatic black water regulating valve When the regulating valve uses graphite-asbestos as the packing, lubricating oil should be added to the packing once about three months to ensure that the regulating valve is sensitive and easy to use. If it is found that the packing pressure cap is very low, the packing should be made up. If the PTFE dry packing is found to be hardened, it should be replaced in time; the operation of the regulating valve should be paid attention to during the inspection tour, and the valve position indicator and regulator should be checked Whether the output meets.
For regulating valves with positioners, always check the air source, and deal with problems in time if problems are found; always keep the regulating valve sanitary and all parts intact and easy to use. Common faults and their cause-the regulating valve does not operate. The problems and reasons are as follows: no signal, no gas source. The gas source is not open, and it freezes in winter due to the water in the gas source.
Pneumatic control valve uses compressed air as power source, cylinder as actuator, and uses electrical valve positioners, converters, solenoid valves, retaining valves and other accessories to drive the valve to achieve on-off or proportional adjustments and receive industrial The control signal of the automation control system completes the adjustment of the pipeline medium: flow, pressure, temperature and other process parameters. Pneumatic control valve is characterized by simple control, fast response, and no need to take additional explosion-proof measures.
Cause the air pipe to be blocked or the filter and the pressure reducing valve to be blocked and malfunction, the compressor is faulty, and the air source main pipe is leaking. There is air source, but no signal. The regulator is faulty, the signal tube is leaking; the bellows of the positioner is leaking; the regulating omentum is damaged. The positioner has no air source. The filter is clogged; the pressure reducing valve is faulty, and the pipeline is leaking or clogged. The positioner has air source but no output.
The saving hole of the positioner is blocked. There is signal, no action. The valve core falls off, the valve core is stuck with the society or the valve seat; the valve stem is bent or broken; the valve seat and the valve core are frozen or burnt; the actuator spring is rusted due to long periods of inactivity.
