Pump Shut off head/Vertical lift

[bif]

I have a pump datasheet quoting a 50 m shut off head.
The NPSHr is 1m and there is 10m available - both quoted on the datasheet.
Is the vertical lift from the pump 50m, or do I need to add the NPSH availble?

 

[BigInch]

pump head is given as a differential, therefore add suction head + pump differential head to get total discharge head.

Don't forget that shutoff head is at flowrate zero and higher flowrates will reduce the pump's differential head and corresponding discharge pressure, so check the pump curve for head at your planned flowrates to see if the total head and pressure will be sufficient there.

http://virtualpipeline.spaces.msn.com

 

[khardy]

"The NPSHr is 1m and there is 10m available - both quoted on the datasheet."

This doesn't quite make sense: when you say "there is 10m available" i take that to mean the NPSHa is 10m. That would not be quoted on the data sheet. NPSHa is what's avialable from the system.

When you say "vertical lift" i assume you mean the maximum vertical distance the pump centerline can be above the surface of the suction side resivor without cavitating?

 

[Artisi]

NPSHr 1m and 10m available is certainly confusing and contradictory. You need to clarify this point before you can establish what the total head across the pump is.

 

[Artisi]

One possible answer is that the pump need a minimum of 1m at the specified flow rate but there is actually 10m available which is the nominal NPSHa available at sea level.
However, this in itself doesn't mean anything as far as the 50m shut-off head is concerned. The 50m is the nominal(pressure) head the pump can develop at zero flow against a closed valve.

 

[BigInch]

Sure maybe the data is confusing, but sort it out. NPSHA or R is irrelevant to the OPs question, whom I think might be confused now.

Discharge head = suction head + pump differential head. If there is 1 m suction head, shutoff discharge head is 1+50 m and if there's 10 m suction head, shutoff discharge head is 10+50.

http://virtualpipeline.spaces.msn.com

 

[bif]

Thanks guys
The pump does require 1m, but it would appear as though there can be up to 12 m available as best/worse case for the application in question (ie storage tank full)
I'll take the total discharge head as the sum of the differential + suction head for the problem I am looking at.