In many industrial fields such as chemical industry, water supply and drainage, and food processing, pumps are the core power equipment for fluid conveying, and their operating status directly determines the efficiency and safety of the production line. Cavitation, insufficient flow and insufficient head are the three most common faults in pump operation, and the three are often cause and effect of each other. If they are not accurately and timely troubleshooted, they will gradually cause permanent damage to the equipment.

-Bonve Pumps Rotary Lobe Pump-

Cavitation is known as the performance killer of pumps, and its essence is physical damage caused by fluid phase transition. When the local pressure on the suction side of the pump is lower than the saturated vapor pressure of the medium, the liquid will vaporize to form a large number of microbubbles. After entering the high-pressure area, the bubbles collapse instantaneously, generating a local water hammer of hundreds of megapascals, which repeatedly impacts the metal surface and causes fatigue damage. Excessively high installation height, large resistance of the suction pipeline, increased medium temperature or long-term large-flow operation will all induce cavitation. On-site, it can be quickly identified by "listening to the popping sound like fried beans, feeling high-frequency vibration, and seeing violent fluctuations of the pressure gauge". If the symptoms disappear after closing the outlet valve slightly, it can be further confirmed.

The core of prevention and control is to ensure that the available net positive suction head is greater than the required net positive suction head (NPSHa > NPSHr), which can be achieved by reducing the installation height, increasing the diameter of the suction pipeline, and simplifying the pipeline layout; for impellers that have suffered cavitation, the inlet edge can be thinned to about 1mm and polished into a streamlined fillet. Not only centrifugal pumps are susceptible to cavitation, but also positive displacement pumps such as rotor pumps need to focus on the suction pressure when conveying high-temperature and high-viscosity media to avoid pitting damage on the rotor meshing surface caused by cavitation.

Insufficient flow is mostly caused by multiple factors. Air leakage and blockage on the suction side, and insufficient water entry depth of the foot valve (which needs to be greater than 1.5 times the diameter of the water inlet pipe) are the most common inducements; wear of the internal sealing ring or impeller of the pump, blockage of the flow channel, and low rotational speed (flow is proportional to rotational speed) will directly reduce the conveying capacity; excessively long system pipelines, too many elbows or insufficient opening of the outlet valve will also limit the flow. When troubleshooting, first check the sealing performance of the suction side and the state of the filter screen, then verify the rotational speed and the wear of the internal parts of the pump, and finally optimize the pipeline layout.

Insufficient head needs to be addressed from three aspects: electrical, mechanical and system matching. Motor reversal will lead to a sharp attenuation of the head, and the impact of reduced rotational speed is more significant (head is proportional to the square of the rotational speed); blockage of the impeller flow channel, excessive internal leakage or impeller damage will directly weaken the hydraulic performance; if the pump itself has normal performance, it may be caused by the deviation of the operating point or undersized selection. When solving the problem, first adjust the motor steering and rotational speed, then clean the flow channel and replace worn parts, and if necessary, meet the demand by series-parallel pump units or re-selection.

Fault troubleshooting must follow the principle of "outside first, inside later; simple first, complex later". At the same time, regular inspections, monitoring of key parameters, and control of selection and pipeline design can effectively ensure the long-term stable operation of pump units.

Bonve pump always adheres to the philosophy of "Wholeheartedly Making Good Rotor Pumps," committed to providing global customers with customized conveying and mixing solutions. If you have technical inquiries, selection needs, case references, or other cooperation intentions related to Bonve rotor pumps, please feel free to contact us.  

Service Hotline: 0574-87588986 13586591794  

Official Website: www.bvpumps.com  

Business Email: market@bonvepumps.com  

We look forward to working with you to drive efficiency and innovation in industrial fluid transmission with precision technology.