Precautions for On-Site Use of Pneumatic Butterfly Valves

Pneumatic Butterfly Valves are typically assembled combinations formed by pneumatic actuators, valve bodies, and associated accessories after connection, installation, and commissioning. This article primarily introduces on-site usage precautions for Pneumatic Butterfly Valves.
In mid-June 2013, a blower factory in Shandong purchased a batch of pneumatic regulating butterfly valves for use in the sewage treatment project of the West-to-East Gas Pipeline Project in Xinjiang. According to on-site personnel, the equipment failed to operate normally. The company dispatched technicians to investigate the situation. Below are some issues encountered and their solutions.
1. The control cabinet sends signals, but the valve fails to actuate. Upon on-site inspection, it was found that the pneumatic regulating butterfly valve was equipped with both a positioner and an additional Solenoid Valve. The strong electrical interference from the Solenoid Valve disrupted the signal output of the control cabinet, preventing the valve from receiving signals and thus causing it to malfunction.
Solution: Remove the Solenoid Valve and eliminate strong electrical interference to ensure normal operation (Note: The function of the Solenoid Valve is to control the opening and closing of the valve, while the actuator uses a 4 to 20 mA signal to regulate the valve's position. Therefore, installing a solenoid valve is unnecessary when an actuator  is already in place).
2. After automatically switching to manual mode, it cannot revert back to automatic mode. This is caused by the field operator applying excessive force, resulting in over-amplitude movement of the clutch, which leads to internal gear jamming and prevents the switch back to automatic.
Solution: When engaging/disengaging the clutch, rotate the handwheel back and forth to disengage the internal turbine, enabling smooth manual-automatic switching (always pull up the yellow-colored snap ring beside the handwheel during switching).
3. The valve was functioning normally. It was only after communicating with the on-site wiring personnel that we learned the wires at the site were all thick and hard, making connections inconvenient. This led to a screw falling off. The wiring personnel directly tightened the module with a long screw, causing the module to be pushed and resulting in a short circuit.
Solution: Replace the conventional screw model; recommend using thinner wires for the connected circuits.