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6 years ago in Discussion By Fern G

How to choose between centrifugal pumps and positive displacement pumps?

I’m unable to choose between centrifugal pumps and positive displacement pumps. Can someone tell me on what are the aspects that I should look into while choosing one among them?

All Answers (4 Answers In All)

By Arjun Patel Answered 6 years ago

Fern, choosing between a centrifugal pump and a positive displacement pump is not a straightforward task. Even I struggled with this process during my research period. The most important aspect that needs to be considered is flow rate & pressure head.

By Fern G Answered 6 years ago

Can you please explain them briefly?

By Arjun Patel Answered 6 years ago

Yeah sure! Both the pumps behave differently regarding flow rate and pressure head: The centrifugal pump has varying flow depending on the pressure or head of the system. Whereas the positive displacement pump has a constant flow despite of the system pressure or head. So if you want constant flow then go for positive displacement pump.

By Jang Bahadur Singh Answered 6 years ago

Fern, not just flow rate, you will have to consider:
1.Capacity and Viscosity
In a centrifugal pump the flow reduces when the viscosity increases
In a positive displacement pump the flow increases when viscosity increases. Positive displacement pumps are suited for higher viscosity applications
2.Net Positive Suction Head
In a centrifugal pump, (NPSH) net positive suction head varies as a function of flow determined by pressure
In a positive displacement pump, net positive suction pump varies as a function of flow determined by speed.

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