What are the disadvantages of centrifugal pumps running at low flow rates for long periods of time

　　Centrifugal pump flow can be infinitely adjusted by various methods, in general, the pump in the rated point of the working condition is the most reasonable, but sometimes due to certain reasons caused by the pump in the small flow condition point of operation, it will cause some of the following negative effects.

　　What are the disadvantages of centrifugal pumps running at low flow for a long time?

　　(1) efficiency reduction, power consumption increases. Centrifugal pumps are generally designed to maximize efficiency in the rated I condition point near. If the centrifugal pump in the small flow operating point, its operating efficiency will fall very quickly, in general, the same pump flow is smaller, the smaller the efficiency, and thus in the small flow operating conditions is very uneconomical. In general, this time it is necessary to re-equip with a suitable high-efficiency small pump.

　　(2) vibration noise increases, causing environmental pollution, damage to pump parts, affecting the service life of the pump. At the point of design condition, due to the direction of the liquid flow and the direction of the vane is the same, the loss of decurrent, impact loss, vortex loss is relatively small, close to zero. But the pump works in the small flow area, due to deviation from the design point, resulting in the pump overflow parts of the loss, impact loss, vortex loss further increase, these losses in the generation of a large number of hydraulic noise and mechanical vibration at the same time.

　　(3) The pump internal reflux increases substantially, the heat of cohesion increases, so that the temperature of the liquid inside the pump rises, causing the pump body to heat up, affecting the mechanical properties of the pump parts, but also deteriorate the pump's cavitation performance, further affecting the pump suction conditions.

　　(4) The radial force of the centrifugal pump increases, deteriorating the pump rotor force situation. As the pump works in the small flow area deviates from the design working condition point, the liquid flow speed inside the vortex chamber is reduced, but according to the speed triangle analysis, it can be seen that the liquid outflow speed inside the impeller is increased instead, so that the liquid can not be converged to form an impact, and the pressure is constantly increased to produce radial force.