The centrifugal pump is built on a simple principle: Liquid is led to the impeller hub and by means of the centrifugal force it is flung towards the periphery of the impellers. The construction is fairly inexpensive, robust and simple and its high speed makes it possible to connect the pump directly to an asynchronous motor. The centrifugal pump provides a steady liquid flow, and it can easily be throttled without causing any damage to the pump.
The inlet of the pump leads the liquid to the centre of the rotating impeller from where it is flung towards the periphery. This construction gives a high efficiency, and is suitable for handling pure liquids. Pumps, which have to handle impure liquids, such as wastewater pumps, are fitted with an impeller that is constructed especially to avoid that objects get stocked inside the pump.
If a pressure difference occurs in the system while the centrifugal pump is not running, liquid can still pass through it due to its open design.