Performance parameters of pumps

Mainly flow and head, in addition to shaft power, speed and necessary cavitation allowance. Flow refers to the amount of liquid output through the outlet of the pump in a unit time, generally using volume flow; head is the energy increment from the inlet to the outlet of the pump conveying liquid per unit weight. For volume pumps, energy increment is mainly expressed by the increase of pressure energy, so it is usually expressed by pressure increment instead of head. Pump efficiency is not an independent performance parameter, it can be calculated by other performance parameters such as flow rate, head and shaft power according to formula. On the contrary, the shaft power can also be calculated with known flow rate, head and efficiency.

There is a certain interdependence between the various performance parameters of the pump. By testing the pump, the parameters can be measured and calculated separately, and expressed by drawing curves. These curves are called pump characteristic curves. Each pump has a specific characteristic curve, which is provided by the pump manufacturer. Usually, the recommended performance section is indicated on the characteristic curve given by the factory, which is called the working range of the pump.