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PD pump performance

PD pump performance

PD pump performance

(OP)
Hye,

I would like to seek any expert view.

If i want to buy the positive displacement pump, do I need to provide the NPSHa value?
And what is the impact to this pump performance if the NPSHr value is higher than NPSHa?

Thank you.

RE: PD pump performance

Yes you need to supply all relevant data

If NPSHA < NPSHR, the pump may not work, could suffer damage or at the least performance would suffer.

Different PD pumps have different capabilities for NPSH.

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way

RE: PD pump performance

(OP)
Thank you for the feedback.

FYI, the medium transfer is fuel with viscosity about 20cSt at 20degC.
With PD pump gear type, why this pump couldn't work if the NPSHa<NPSHr?

Is it because of the cavitation will be occurred at the inlet pump?

Or pressure loss in the pipeline resist the pump to operate?

RE: PD pump performance

It might "work", but could be pumping a mixture of liquid and gas. A gear type unit would just make a lot of noise and not produce the flow or pressure it was designed for. Over any reasonable time period ( days / weeks) this could easily damage the unit at which point the pump vendor will not take responsibility as you've been operating it outside the required inlet conditions.

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way

RE: PD pump performance

(OP)
thumbsup2
Tq

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