Pneumatic butterfly valve is usually a combination of pneumatic actuator, valve body and some accessories after installation and debugging. This article mainly introduces the precautions for on-site use of pneumatic butterfly valves.
In mid-June 2013, a blower factory in Shandong purchased a batch of pneumatic regulating butterfly valves and put them into the sewage treatment in the Xinjiang West-East Gas Pipeline Project. According to the feedback from the on-site personnel that the equipment could not operate normally, the company sent technicians to the site to understand the situation. The following Here are some situations and solutions.
1. The valve does not act when the control cabinet sends a signal. According to the on-site observation of the pneumatic regulating butterfly valve, a solenoid valve is installed on the premise of installing the positioner. The strong electricity of the solenoid valve interferes with the signal output of the control cabinet, and the valve cannot receive the signal, so Can not work normally.
Solution: Remove the solenoid valve and remove the strong electrical 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 to 20 mA signal, so when installing It is not necessary to install a solenoid valve if there is a positioner).
2. After the automatic switch to the manual state, the switch will not return to the automatic state; because the on-site operator uses too much force and the clutch is too large, the internal gear is stuck, and it cannot be turned back to the automatic state.
Solution: When the clutch is pulled, the handwheel must be rotated back and forth to disengage the internal turbine, so as to easily achieve automatic manual switching (be sure to pull up the yellow card sleeve next to it when switching automatically by hand).
3. The valve works normally, but the feedback is always in a 100% state. Only after communicating with the on-site wiring personnel did we know that the on-site wires are all thick wires, and the connection with strong hardness is not very convenient, resulting in a screw falling off. A long screw is tightened so that the module is pushed against by the screw, causing a short circuit.
Solution: change to the conventional screw type; it is recommended to use thin wires for the connected lines.