The outlet flow rate of a single-stage centrifugal pump is much lower than the rated flow rate
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The outlet flow rate of this single-stage centrifugal pump is far below its rated flow rate; the actual flow rate is approximately 30% of the rated value, and the vibration of the pump body exceeds 4.5 mm/s. Could someone please suggest a solution?
I once encountered an issue with the installation of an outlet valve – the actuator was installed in the wrong direction. From a practical perspective, issues such as pipe blockages, excessive gaps at the positions where the impeller meets the volute, and damaged impeller seals are likely to be the causes; it’s worth checking these areas.
The pressure is building up; the pump is vibrating like this. Check the outlet valve or turn on the return flow – it should not be a serious problem
The operating conditions require such a high flow rate
The operating conditions require such a high flow rate
If the current pressure is above 90% of the rated value, and the current after the valve is fully opened is above 80% of the rated value, then there is no problem with the pump. Is the opening degree of the outlet valve low? If flow rate is to be controlled by using the outlet valve for low-flow operation, this is feasible in the short term; however, if the valve remains open for an extended period, the clearance between the impeller and the valve seat will gradually increase, leading to a decline in pump efficiency. Moreover, the valve disc is prone to erosion, and when the valve is closed it may not seal properly. Prolonged friction between the fluid inside the pump and the impeller can cause vaporization, resulting in cavitation. Seals that lack proper flushing are likely to be damaged, leading to leaks between the moving and stationary parts. There is a problem with the selection of the pump; either the process was modified later to select a suitable pump, or the manufacturer was asked to modify the impeller, or else an outlet return line needs to be installed
I’d like to add that the high vibration is likely due to cavitation; the outlet valve of the pump is open to a small degree, and the impeller keeps working, which causes the temperature of the fluid inside the pump to rise, leading to vaporization of the liquid. What kind of fluid are you using, and what is the temperature?
Is the head sufficient? Is there cavitation? It is not recommended to check the fit of the impeller mouth ring, or possible design defects in the impeller itself.
Is the head sufficient? Is there cavitation? It is not recommended to check the fit of the impeller mouth ring, or possible design defects in the impeller itself.