Precautions for field use of pneumatic butterfly valve

Pneumatic butterfly valve is usually a combination of pneumatic actuator, valve body and accessories after connection, installation and commissioning. This paper mainly introduces the precautions for the field use of pneumatic butterfly valve.
In mid June 2013, a blower factory in Shandong purchased a batch of pneumatic regulating butterfly valves for sewage treatment in Xinjiang West to east gas transmission project. According to the on-site personnel, the equipment could not operate normally. The company sent technicians to the site to understand the situation. The following are some conditions and solutions.
1. The control cabinet sent a signal and the valve did not act. After field observation, the pneumatic regulating butterfly valve was equipped with a solenoid valve on the premise of installing the positioner. The strong current of the solenoid valve interfered with the signal output of the control cabinet, and the valve could not receive the signal, so it could not work normally.
Solution: remove the solenoid valve and remove the strong current interference to the normal operation of the equipment (Note: the function of the solenoid valve is to switch the valve, and the function of the positioner is to control the opening of the valve with a 4-20 mA signal, so it is not necessary to install the solenoid valve on the premise of installing the positioner).
2. After automatic switching to manual state, it will not switch back to automatic; Due to the excessive force used by the on-site operator and the excessive pulling range of the clutch, the internal gear is stuck and cannot be pulled back automatically.
Solution: when pulling the clutch, the hand wheel should rotate back and forth to disengage the internal turbine, so as to easily achieve manual automatic switching (when manual automatic switching, be sure to pull up the Yellow ferrule next to it).
3. The valve works normally, but the feedback is always in a 100% state. Only through the on-site wiring personnel do they know that the on-site wires are thick wires with strong hardness, and the connection is not very convenient, resulting in the drop of a screw. The wiring personnel directly tighten a long screw, so that the module is pushed by the screw, causing a short circuit.
Solution: replace the conventional screw model; It is recommended to use thin wires instead of connecting lines.