A centrifugal pump is a machine that imparts energy to a fluid, causing it to flow, rise to a higher level or both. It actually uses acceleration (not centrifugal force) to transform mechanical (rotational) energy into hydraulic energy. Dynamic energy (acceleration) is continually added to increase the hydraulic energy of the fluid (water).
A centrifugal pump consists of an impeller (paddle wheel), a volute (bowl) and motor. The rotation of the impeller (caused by the dynamic energy from the motor) forces water from its entry point at the impeller eye, through the impeller’s vanes and into the volute. As water moves from the center of the circular impeller to its periphery, its velocity increases. When it reaches the volute, velocity is transformed into pressure.
The flow and pressure created by a centrifugal pump depends upon the design of its impeller and its peripheral velocity. An impeller’s peripheral velocity is dependent upon its diameter, its rotational speed or both.
Normally, we see centrifugal pumps used throughout the water industry. They are used in low-service situations, to lift water from the source to the treatment plant or for backwashing filters. In high-service situations, they are used to discharge water under pressure to the distribution system. They are also used to lift water from wells and discharge it to the treatment plant, storage facilities or distribution system.
The centrifugal pump is just one of many different types of pumps used in the water industry. It is considered a mainstay of the drinking water and wastewater industry for moving water.