Pump shut off Head

Yes. The kinetic energy of the fluid (mv²/2) relates closely to the potential energy represented by pressure. See also "specific speed" as related to pumps.

Not in total agreement here. Tornado and the OP will do themselves a favour to re-read this:

http://www.engineeringtoolbox.com/centrifugal-pumps-d_54.html

jvrj, are you saying that Tornado (a revered Guru) actually does not know what he is talking about? I like your style.

Not at all Guest, as previous posts of mine have commended him, however, it does seem as if he tends to be the antagonist and abuse these forums with plenty waffle instead of just answering the question. To belittle, or attempt to do so will only attract negative comments from posters like myself and rile people like yourself. Maybe the points system on this forum is favouring those with loads of time on their hands, with good google skills and, as you can see yourself, once a guru you own the forum. Anyway, watch the gurus rate this "off topic"

Well put and once more you show your class. I particularly like the comment "once a guru you own the forum" and your reference to having lots of spare time and good google skills. I refer to these people as google-engineers. I was actually surpirsed to see that your comment was not deleted by Admin or that it was not voted so far off topic that it could not be found. Admin do tend to protect the guru's on this forum, not really sure why.

The article you cite is a good one. I didn't use the same language, but if you think the article and I contradict each other, please state where. See also post 3.

The maximum or "shut-off" head of a centrifugal pump can be expressed as

h_s = (d n / 1840)² (1)

where

h = head (feet)

d = outside diameter impeller (inches)

n = wheel velocity - revolution per minute - (rpm)

Er, what about the impeller-to-casing clearances?

i think this clearance has a relation with hydraulic efficiency of the pump.

where at the correct gap, this is can rise performance of the pump.

please, correct me

Do you disagree with Kaisan's formula?

There probably is, though not many Engineers would bother with it.

What they would use, however, is the original equipment manufacturers' performance curves, which show pressure v. flowrate for any number of shaft speeds, and use the value(s) for pressure where the performance line crosses the flowrate=0 line.

Why anyone would want to operate a pump at this point on the curve is anybody's guess, for a pressure bottle would do the same job with no shaft power input, no destruction of the bearings and seals, and no heating of the impeller casing.