Download NPSH Tutorial

19 Votes

Tutorial and example problems explaining the basics behind Net Positive Suction Head (NPSH). Available in both MS Word and PDF formats.

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Samar

Jul 08 2011 01:05 PM

good

sang

Sep 16 2011 02:57 PM

Pardon my ignorance, but I think there is an error in the NPSH calculation. Since the tank bottom elevation of 10 ft (in the example given) is taken with reference to pump centreline, we need not subtract the pump centreline elevation (of 3 feet) as the NPSH is normally quoted at pump centreline.

Regards
Sanjay

Supriyo Mukherjee

Jan 11 2012 05:42 AM

I also thnk sanjay is right on this otherwise we have to mention liquid level from ground level as 10 ft in the avobe problem reffered. the document should be changed.

cjgorr

Mar 08 2012 05:14 AM

I agrre with the above comments. Normally the elvation or head of the liquid is referred to the center line of the suction so you don´t need to worry about the elevation of the pump with respect to the ground level.
Also, I suggest to change the arithmetic of NPSH as follows:

plus the elevation of the liquid level (if it is higher than the suction inlet nozzle) or minus the elevation of the liquid level (if it is below the suction inlet nozzle) with respect to the suction inlet nozzle

and you can suppress the next bullet.

I have translated your article to spanish, are you interested in a copy?