NPSH r for vertical submersible pumps

Dah! It depends on the pump. Submergence is the term.

Irrigation Water Pumps

Strictly speaking, it's the same situation as a normal centrifugal pump, there is an NPSHr figure (depending on flow) which the pump manufacturer can give you, and need to ensure NPSH available is higher. But in practice, in most situations you don't need to bother. NPSHr is typically 3 - 4m, and if your pump is just submerged you've got about 10m NPSHa.

Exceptions are if it's handling hot water, or the atmospheric pressure on the liquid surface is less than normal, as either of these reduces the NPSHa.

Could be more important to get the sump design right, to avoid vortexing.

Cheers..........Codey

Dear friend,

The pump should be totally submerged, in the fluid/liquid to be pumped. Hence no question of NPSHr. OTHERWISE PUMP CANNOT WORK.

DHAYANANDHAN.S