How to choose a suitable pump

A pump is a mechanical device that transmits a medium by converting the energy provided by an electric motor into hydraulic energy. The first criterion for selecting a pump is the type of medium in question. It is also necessary to consider the technical characteristics of the medium, as they determine the choice of the pump.

Next, in order to correctly size the machine and calculate the operating point of the pump, it is necessary to know a series of parameters such as: flow rate, suction head, discharge head, pressure head loss, etc.

In order to choose the pump that meets your needs, its characteristics need to be determined according to its use.

First of all, you need to determine the type of medium to be transferred in order to avoid corrosion phenomena and thus premature wear of the pump. Therefore, it is essential to know the chemical composition, viscosity and possible solids content of the pumped medium. A comprehensive understanding of all the physical properties of the fluid handled enables you to select the ideal technology for your application and to choose materials compatible with the pumped medium. Before selecting a pump body, you need to refer to the chemical compatibility table.

You then need to check the properties related to the transfer medium, in particular

The required flow rate: generally expressed in m3/h (cubic meters per hour) or GPM (gallons per minute), which will necessarily affect the size and dimensions of the pump.
Suction head (height between the suction pipe inlet and the pump): In general, the suction height must not exceed 10 meters. In addition to this, the use of submersible pumps needs to be considered.
Discharge head (height between the pump and the discharge pipe outlet).
The length of the discharge circuit.
Pressure head loss related to obstructions (valves, bends, etc.) on the pumping circuit.
Availability of a drainage tank that may change the pressure head.
Selection of the pump body according to the temperature
Based on these different values, you can calculate the NPSHa (net positive suction pressure head) of your equipment. Enables you to choose the right pump and avoid the risk of cavitation. You also need to control the efficiency; the efficiency must be optimal at the required nominal flow rate of approximately 30%.