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.

氣動調節閥采用石墨一石棉為填料時，大約三個月應在填料上添加一次潤滑油，以保證氣動調節閥靈活好用。如發現填料壓帽壓得很低，則應補充填料，如發現聚四氟乙燥填料硬化，則應及時更換；應在巡回檢查中注意氣動調節閥的運行情況，檢查閥位指示器和調節器輸出是否吻合；對有定位器的氣動調節閥要經常檢查氣源，發現問題及時處理；應經常保持氣動調節閥的衛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.

氣動調節閥常見故障及產生的原因：

Common faults of pneumatic control valve and their causes:

（一）氣動調節閥不動作

（1） Pneumatic control valve does not act
 

故障現象及原因如下：

The fault phenomena and causes are as follows:

1．無信號、無氣源。①氣源未開，②由于氣源含水在冬季結冰，導致風管堵塞或過濾器、減壓閥堵塞失靈，③壓縮機故障；④氣源總管泄漏。

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．有氣源，無信號。①調節器故障，②信號管泄漏；③定位器波紋管漏氣；④調節網膜片損壞。

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．定位器無氣源。①過濾器堵塞；②減壓閥故障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．定位器有氣源，無輸出。定位器的節流孔堵塞。

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

5．有信號、無動作。①閥芯脫落，②閥芯與社會或與閥座卡死；③閥桿彎曲或折斷；④閥座閥芯凍結或焦塊污物；⑤執行機構彈簧因長期不用而銹死。

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）氣動調節閥的動作不穩定

（2） Unstable action of pneumatic control valve

故障現象和原因如下：

The fault phenomena and causes are as follows:

1．氣源壓力不穩定。①壓縮機容量太小；②減壓閥故障。

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

2．信號壓力不穩定。①控制系統的時間常數（T＝RC）不適當；②調節器輸出不穩定。

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．氣源壓力穩定，信號壓力也穩定，但氣動調節閥的動作仍不穩定。①定位器中放大器的球閥受臟物磨損關不嚴，耗氣量特別增大時會產生輸出震蕩；②定位器中放大器的噴咀擋板不平行，擋板蓋不住噴咀；③輸出管、線漏氣；④執行機構剛性太小；⑤閥桿運動中摩擦阻力大，與相接觸部位有阻滯現象。

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.