The outlet of the centrifugal pump is set too small, and the flow rate required isn’t very high. Is there any way to improve this situation?

This post was last edited by 3983596_FPPZ on 2018-12-21 08:50. I. Solving internal issues requires certain professional skills: 1. Cutting the impeller, but this action leads to a decrease in both flow rate and head; it is necessary to ensure that the performance after cutting meets the requirements of the operating conditions, and this method is generally used when the degree of deterioration is minor； 2. When the number of impeller blades is even, it is possible to consider blocking the flow channels of two adjacent blades symmetrically, thereby reducing the flow rate proportionally. 3. Either replace only the impeller with a lower flow rate, or replace both the impeller and the pump body at the same time.

II. Solutions for external characteristics:
1. Installing a return pipeline to create backflow will result in energy waste.
2. Using variable frequency speed control incurs costs related to the frequency converter; changes in speed also lead to changes in performance parameters, which can be calculated using the proportional laws outlined in professional textbooks.
3. Replacing the pump with one that has a lower flow rate and better suits the operational conditions.

All these measures are related to the actual operating conditions and the difficulty of implementation. Factors such as whether there are personnel familiar with hydraulics, the continuous operation time of the pump, the impact of stopping the pump, the material used for the pump, cost control considerations within the company, equipment management regulations, and the intentions of management all play a role

Use two small pumps; run one normally, and use two when a high flow rate is required.

Currently, there are 2 pumps with the same power level; one is in use while the other serves as a backup. By using a smaller pump, it’s not necessary to have such high power, and there will be no pressure buildup at the outlet, which prevents the seal from being damaged. I initially thought of using it on the pump; now I might need to replace the entire pump. I haven’t considered the pipelines yet. I might have considered too few options! Thank you, Haiyou

For the outlet, simply install a return pipeline, and a flow-limiting orifice plate should be added to this return pipeline.

Referring to the proportional law of centrifugal pumps, this is the principle by which variable frequency drives can improve the operating conditions of pumps. By changing the rotational speed, the flow rate, head, and shaft power change accordingly, which facilitates process adjustment and saves energy.

It would be best to provide the operating conditions required by the current process, those specified in the original design, as well as the current pump specifications and configuration; this will likely help to obtain a better response

Installing an inverter might be a more cost-effective solution; additionally, using a pump of smaller capacity is also a good option

Replace with a custom impeller, tailored to increase the opening of the outlet valve; this reduces the pressure inside the pump chamber, extends the lifespan of the mechanical seal, and reduces vibration. Only the impeller needs to be replaced, without an increase in maintenance workload

This method is well-supported and comprehensive.