what is the meaning of curve of performance in centrifugal pump and positive displacement pump?

Question

i not understand about curve of performance.... can anyone describe about it?

Answer 1

On a graph of pressure vs. discharge, Positive Displacement Pumps (PDPs) will be nearly a vertical line for any given discharge. In other words, they can have extremely high pressures at a given discharge.

Dynamic pumps (of which centrifugal is a type) vary. Generally, as their discharge increases, their pressure decreases.

Answer 2

It means PD pump can handle any pressure(theoretically). If pressure increase, head developed in PD pump will also increase, it happen every time pressure increase. While centrifugal has its own maximum head characteristic.