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Centrifugal Water Pumps

A centrifugal pump is a roto-dynamic pump which uses rotating impellers to increase the flow rate and pressure of the fluid.  This is the most common...

 

A centrifugal pump is a roto-dynamic pump which uses rotating impellers to increase the flow rate and pressure of the fluid.  This is the most common type of pump in use for moving liquids.

It works by means of the liquid entering the pump impeller at the rotating axis and is then moved by the impeller in a radial outward flow or alternatively axially into a diffuser or volute chamber.  From there it will exit into the piping system.

Although centrifugal pumps are generally associated with the radial flow type, it is also used for impeller type roto-dynamic pumps.  There are many different impeller pumps including radial flow pumps, axial flow pumps, mixed flow pumps, gravity pumps and edector-jet pumps, The main specifications to look for when researching centrifugal water pumps are horsepower, flow rate and outlet pressure in feet or meters of head.  You also want to look at inlet suction in suction feet or meters of head.  In order to calculate the head, take the number of feet or meters the pump can raise or lower a column of water at atmospheric pressure.

Also take into consideration that many engineers will refer to a term ‘specific speed’ which they use to identify the ideal pump type for any combination of head and flow rate. The efficiency of a pump is determined as the ratio of the power imparted on the liquid by the pump in direct relation to the power supply needed to drive the pump.  This value will range considerably in pumps because of various factors such as viscosity of liquid as well the operating heads relation to the discharge.  Centrifugal water pumps generally experience a peak midway through the flow rate which is called the peak efficiently and then it will decline again as the flow rate rises.  All this pump performance will be supplied by the manufacturer but remember that your pump will decline in efficiencies over time.