Pneumatic diaphragm pumps often encounter malfunctions during prolonged, high-intensity operation. Do you know what the common faults are and how to resolve them? Today, the pump experts at Shanghai Shenyin Pump Manufacturing Co., Ltd. will explain the troubleshooting solutions for these pumps.
a. Pump lacks power; pumping speed slows down. This phenomenon generally stems from the following causes: First, a drop in air supply pressure. Check the inlet pressure gauge; a reading of 4–7 kg is normal. Then, check the opening of the air supply valve. If a solenoid valve controls the air supply, inspect the plastic valve disc for damage that might prevent it from opening fully.
Second, the muffler is clogged, preventing rapid air exhaust and slowing down the pumping speed.
Third, excessive moisture or impurities in the compressed air. These can clog the air inlet or jam the air distribution valve spool after entering the valve assembly. Fourth, the upper or lower end caps of the air distribution valve are damaged and leaking air due to prolonged impact from the valve spool. Fifth, air leakage occurs because the four sealing rings on the central shaft are worn.
b. Reduced flow rate. This phenomenon generally stems from the following causes: First, the inlet/outlet check valves (plastic balls) are worn and reduced in size, or strip-shaped objects and large particles are jamming the balls. This causes fluid to backflow from the discharge port during suction and forces material back through the inlet port during discharge. Second, the diaphragm has deformed due to prolonged stretching, reducing the volume of the material chamber. Third, the thick black diaphragm layer is damaged, preventing the central shaft from completing its full stroke.
c. Pump fails to operate. This can be caused by several factors: First, the valve spool is severely worn and jammed. Second, the central shaft bushing is worn; the copper bushing should be replaced in this case. Third, the screws at either end of the central shaft have fallen off. Fourth, both diaphragm layers have ruptured. Fifth, the pump is positioned upside down or laid flat, preventing the valve spool from returning to its proper position (applies to first- and second-generation models). d. Impurities or oil contamination in the pumped material. This is usually caused by a ruptured diaphragm.
e. Material leakage at the inlet or outlet. Possible causes include: first, the screws are not tightened; second, the ball seat is deformed or the O-ring is damaged; and third, the pump casings at both ends are tilted due to misalignment of the mounting holes, causing the discharge or suction ports to be out of alignment (i.e., not on the same plane). Pneumatic double-diaphragm pumps are capable of gently and safely conveying critical materials; they are also well-suited for handling highly corrosive liquids, abrasive materials, flammable or explosive fluids, and many high-viscosity substances.
Troubleshooting solutions for pneumatic diaphragm pumps
We hope this proves helpful to you.