What are the disadvantages of long-term small flow operation of centrifugal pumps?
(1) Efficiency decreases and power consumption increases. Centrifugal pumps are generally designed so that the highest efficiency point is near the rated I point. If the centrifugal pump is running at a small flow rate, its operating efficiency will drop quickly. In general, the smaller the flow rate of the same pump, the lower the efficiency. Therefore, it is very uneconomical to run at a small flow rate. . Under normal circumstances, it is necessary to re-equip with a suitable high-efficiency small pump.
(2) Vibration and noise increase, causing environmental pollution, damaging pump parts and affecting the service life of the pump. At the design condition point, because the direction of the liquid flow is consistent with the direction of the blade, the loss of flow loss, impact loss, and vortex loss are relatively small, close to zero. However, when the pump is working in a small flow area, due to the deviation from the design point, the flow loss, impact loss, and vortex loss of the pump flow component are further increased. These losses are accompanied by a large amount of hydraulic noise and mechanical vibration.
(3) The internal recirculation of the pump increases significantly, and the cohesion heat increases, causing the temperature of the liquid in the pump to rise, causing the pump body to heat up, affecting the mechanical performance of the pump parts, and also worsening the pump's cavitation performance, further affecting the pump Inhalation conditions.
(4) The radial force of the centrifugal pump is increased, which deteriorates the force of the rotor of the pump. Because the pump deviates from the design condition point when working in the small flow area, the liquid flow velocity in the vortex chamber decreases, but according to the velocity triangle analysis, the liquid outflow velocity in the impeller increases instead, so that the liquids cannot converge, form an impact, and continuously increase the pressure to produce Radial force.
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