Is it possible to reduce the pump’s flow rate by varying the frequency without losing too much head?
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Hello everyone, due to changes in the raw materials during production, it is necessary to reduce the flow rate to half of the designed value. Original pump design: inlet pressure of 0.7 MPa, outlet pressure of 2.3 MPa, and flow rate of 7.5–7.9 t/h (the pump’s maximum flow rate is 4–9 t/h). The current operating conditions are: inlet pressure of 0.5 MPa, outlet pressure of 2.8 MPa, and flow rate of 4 t/h. As the operating conditions are set to change again, it is necessary to adjust the pump’s flow rate to 2–2.54 t/h. I would like to ask if it is possible to add an inverter in order to reduce the pump’s speed, thereby lowering the flow rate while still maintaining an outlet pressure of 2.0 MPa. Note: The pump does not have a return line; the flow rate is controlled solely through the opening degree of the pump’s outlet control valve.
It’s not clear what type of pump it is; it might be a multi-stage pump or some special type of single-stage LF pump. It’s unlikely that variable frequency control can meet the requirements resulting from changes in operating conditions. For such a low flow rate, it’s sufficient to use a bypass control system – there’s no need to worry about efficiency
According to the proportional relationship between the pump’s rotational speed and frequency, changing the frequency means changing the speed. When the speed changes, the flow rate, head, and power also change
This post was last edited by Huang Bo_REH3B on 2021-6-28 at 11:30. I would like to ask the experts: isn’t it possible to simply use an outlet valve to build up pressure? Why though? Sorry... I didn’t see the limit on data usage. . . .
If it operates at low flow rates all the time, it’s possible to simply replace the pump. After all, the cost of using variable frequency drives is not low either. However, with variable frequency drives, it’s possible to achieve a wider range of flow rate controls, which makes it more energy-efficient.
Sure, as you said, it will definitely change the stress! There are many ways to control this operating condition of yours
This post was last edited by Zhongheng Pump Industry on 2021-7-14 at 11:02. Hello, original poster! It is my personal judgment that you are using a centrifugal pump, whose flow rate can be adjusted through frequency conversion, but the head is affected even more significantly. If it is a positive displacement pump (gear pump, screw pump, rotor pump), it can be adjusted via frequency conversion. The easiest way is to install a return pipe on the centrifugal pump. I hope this can help you. You can leave a message or contact me by phone at 13313170275 – Zhongheng Pump Industry (the same number on WeChat)