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 and put them into use in the sewage treatment of 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 sends a signal and the valve does not act. After on-site observation, the pneumatic regulating butterfly valve is equipped with a solenoid valve on the premise of installing the positioner. The strong current of the solenoid valve interferes with the signal output of the control cabinet, and the valve cannot receive the signal, so it cannot 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 4 to 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 cannot be switched 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.
