Pneumatic control valve performance will work quality directly affect the control system of the. As the pneumatic control valve in the field is in direct contact with the medium being transferred, the working environment is very bad, so prone to failure. In the production process, in addition to rule out any of these faults, but also the need for regular maintenance and periodic maintenance. Especially the regulating valve on the use of the environment particularly bad, more attention should be paid to maintenance and periodic maintenance.

Therefore, the pneumatic control valve in the installation should pay attention to the following aspects:

Maintenance of pneumatic control valve:

When the control valve with graphite asbestos packing, should be about three months to add a lubricating oil in the packing, to ensure that the valve and flexible to use. Found filling pressure cap is very low, should be added fillers, such as found in PTFE packing sclerosis, should be replaced; should pay attention to running the tour check valve, check valve position indicator and the regulator output is consistent; on the control valve with positioner should always check the gas source, identify problems timely; keep adjusting valve part of the health and integrity of the easy to use.

Common faults and causes:

Regulating valve does not work. The following fault phenomenon and reason:

No signal, no source: source. As the gas source water freezing in the winter, leading to duct blockage or filter, valve plug failure. Compressor failure. The air duct leakage.

A gas source, no signal: regulator failure. Signal pipe leakage. The corrugated pipe leak locator. Regulate retinal chip damage.

Air-free locator: filter clogging. The relief valve failure. Pipeline leak or blockage.

A gas source locator, no output: locator orifice plug.

E. signal, no movement: ① spool off, the stuck valve and valve seat. Stem bent or broken. Spool seat block frozen or coke dirt. Actuator spring for a long time without rust.

(2) valve action is not stable, the following fault phenomenon and reason:

A. air pressure instability: compressor capacity is too small. The relief valve failure.

B. signal pressure instability: time constant control system (T=RC) is not appropriate. The regulator output instability.

C. air pressure stability, the signal pressure is stable, but still not stable valve action: locator amplifier valve wear off by the dirt is not strict, increase gas consumption in particular will produce output shocks. Locator amplifier nozzle plate is not parallel, the baffle can't cover the nozzle. Output pipe, line leak. Actuator stiffness is too small. The friction movement of the stem, a block in contact with the phenomenon.