Pneumatic regulating butterfly valve is composed of pneumatic actuator, positioner and triple eccentric butterfly valve.
In the industrial automation process control, the pneumatic regulating butterfly valve is the final control element that changes the process parameters such as flow, pressure, temperature, liquid level, etc. of the medium by means of power operation by receiving the control signal output by the regulating control unit.
During the use of the pneumatic regulating butterfly valve, the following faults of the air supply system may occur.
1. The instrument pipeline is blocked. Because the regulating butterfly valve is at the end of the instrument branch, the debris in the pipeline is easy to accumulate and block, resulting in the pressure of the instrument pipe is too low, the regulating valve cannot be fully opened and fully closed, or even the regulating valve does not operate.
2. The air filter pressure reducing valve is faulty. The air filter pressure reducing valve is used for a long time with too much dirt, the pressure reducing valve leaks air, and the set output pressure of the pressure reducing valve is too low, so that the output instrument wind pressure is less than the specified pressure, resulting in the valve action is slow, and it cannot be fully opened or closed. No action.
3. Copper pipe connection failure. The copper pipe is aging and leaking, and the joint connection is loose or blocked, so that the air pressure of the instrument signal is low, so that the regulating valve does not operate, cannot be fully opened and fully closed, and the valve position is unstable in the manual state, resulting in regulation oscillation.
4. Instrument system failure. The air compressor station is abnormal, the purification air tank of the installation is abnormal, the water is not cut in time, the air line is frozen, the instrument air line leaks or is blocked by stolen goods, causing the instrument air pressure of the installation to be too low or even no wind.
5. The valve of the instrument air branch line is not opened, resulting in the non-action of the regulating valve, which often occurs during the overhaul of the device and the start-up period after the transformation.