Pneumatic control valve is widely used in petroleum, chemical, electric power, metallurgy and other industrial enterprises in various industries due to its simple control, fast response, and intrinsic safety, without additional explosion-proof measures. We have to pay attention to its longevity. How can we make it live longer? Then daily inspection and maintenance are essential. Next, Weifang Tianhe Valve Manufacturer will introduce the inspection and maintenance of pneumatic control valve.

气动调节阀采用石墨一石棉为填料时，大约三个月应在填料上添加一次润滑油，以保证气动调节阀灵活好用。如发现填料压帽压得很低，则应补充填料，如发现聚四氟乙燥填料硬化，则应及时更换；应在巡回检查中注意气动调节阀的运行情况，检查阀位指示器和调节器输出是否吻合；对有定位器的气动调节阀要经常检查气源，发现问题及时处理；应经常保持气动调节阀的卫生以及各部件完整好用。

When graphite asbestos is used as the packing for the pneumatic control valve, lubricating oil should be added to the packing once every three months to ensure the flexibility and ease of use of the pneumatic control valve. If the packing gland is found to be pressed very low, the filler shall be supplemented. If the PTFE dry filler is found to be hardened, it shall be replaced in time; Pay attention to the operation of the pneumatic control valve during the patrol inspection, and check whether the valve position indicator is consistent with the output of the regulator; For pneumatic control valves with positioners, the air source shall be checked frequently, and problems found shall be handled in a timely manner; The sanitation of pneumatic control valve and the integrity of all parts shall be kept frequently.

气动调节阀常见故障及产生的原因：

Common faults of pneumatic control valve and their causes:

（一）气动调节阀不动作

（1） Pneumatic control valve does not act
 

故障现象及原因如下：

The fault phenomena and causes are as follows:

1．无信号、无气源。①气源未开，②由于气源含水在冬季结冰，导致风管堵塞或过滤器、减压阀堵塞失灵，③压缩机故障；④气源总管泄漏。

1. No signal or air source. ① The air source is not turned on, ② the air duct is blocked or the filter and pressure reducing valve are blocked and out of order due to the freezing of water in the air source in winter, ③ the compressor fails; ④ The main air supply pipe leaks.

2．有气源，无信号。①调节器故障，②信号管泄漏；③定位器波纹管漏气；④调节网膜片损坏。

2. There is air source but no signal. ① Regulator failure, ② signal pipe leakage; ③ Positioner bellows leaks; ④ The adjusting omentum is damaged.

3．定位器无气源。①过滤器堵塞；②减压阀故障I③管道泄漏或堵塞。

3. The positioner has no air supply. ① The filter is blocked; ② Pressure reducing valve failure I ③ Pipeline leakage or blockage.

4．定位器有气源，无输出。定位器的节流孔堵塞。

4. The positioner has air supply but no output. The orifice of the positioner is blocked.

5．有信号、无动作。①阀芯脱落，②阀芯与社会或与阀座卡死；③阀杆弯曲或折断；④阀座阀芯冻结或焦块污物；⑤执行机构弹簧因长期不用而锈死。

5. There is signal but no action. ① The valve core falls off, ② the valve core is stuck with the society or the valve seat; ③ The valve rod is bent or broken; ④ Frozen valve seat and valve core or coke block dirt; ⑤ The actuator spring is rusted due to long-term disuse.

（二）气动调节阀的动作不稳定

（2） Unstable action of pneumatic control valve

故障现象和原因如下：

The fault phenomena and causes are as follows:

1．气源压力不稳定。①压缩机容量太小；②减压阀故障。

1. The air supply pressure is unstable. ① The compressor capacity is too small; ② The pressure reducing valve is faulty.

2．信号压力不稳定。①控制系统的时间常数（T＝RC）不适当；②调节器输出不稳定。

2. The signal pressure is unstable. ① The time constant (T=RC) of the control system is inappropriate; ② The regulator output is unstable.

3．气源压力稳定，信号压力也稳定，但气动调节阀的动作仍不稳定。①定位器中放大器的球阀受脏物磨损关不严，耗气量特别增大时会产生输出震荡；②定位器中放大器的喷咀挡板不平行，挡板盖不住喷咀；③输出管、线漏气；④执行机构刚性太小；⑤阀杆运动中摩擦阻力大，与相接触部位有阻滞现象。

3. The air source pressure is stable, and the signal pressure is also stable, but the action of the pneumatic control valve is still unstable. ① The ball valve of the amplifier in the positioner can not be closed tightly due to the wear of dirt, and the output vibration will occur when the air consumption increases especially; ② The nozzle baffle of the amplifier in the positioner is not parallel, and the baffle cannot cover the nozzle; ③ Air leakage of output pipe and line; ④ Actuator rigidity is too small; ⑤ The friction resistance of the valve rod is large during movement, and the contact part is blocked.