Pump unit performance parameters are mainly flow and head, in addition to the shaft power, speed and the necessary cavitation margin. Flow is defined in unit time through the pump outlet output quantity of the liquid, the general use of volume flow; lift conveyor unit weight are liquid from the pump entrance to the export of energy increment, for positive displacement pumps, energy increment is mainly reflected in the pressure will increase, so usually with the increase of pressure instead of head to represent. Pump unit efficiency is not an independent performance parameters, it can be other performance parameters such as flow, head and shaft power calculated by the formula.
When selecting the pump unit, it is not important to distinguish the performance of the pump unit, the power is not important, but the efficiency of the unit. In the same head, the same flow rate, the small power efficiency, it also shows that the performance is good.
