Centrifugal pump

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Warman centrifugal pump in a Coal Handling and Preparation Plant (CHPP) application

A centrifugal pump is a rotodynamic pump that uses a rotating impeller to increase the velocity of a fluid. Centrifugal pumps are commonly used to move liquids through a piping system. The fluid enters the pump impeller along or near to the rotating axis and is accelerated by the impeller, flowing radially outward into a diffuser or volute chamber, from where it exits into the downstream piping system. Centrifugal pumps are used for large discharge through smaller heads

1 History
2 How it Works
3 Multistage Centrifugal Pumps
4 Footnotes
5 Problems in Centrifugal Pumps
6 See also

[edit] History

A water or mud-lifting machine that, according to the Brazilian historian of science Reti, "must be characterized as the prototype of the centrifugal pump" appeared as early as 1475 in a treatise by the Italian Renaissance engineer Francesco di Giorgio Martini.^[1] True centrifugal pumps were not developed until the late 1600's, when Denis Papin made one with straight vanes. The curved vane was introduced by British inventor John Appold in 1851.

[edit] How it Works

A centrifugal pump works by the conversion of the rotational kinetic energy, typically from an electric motor or turbine, to an increased static fluid pressure. This action is described by Bernoulli's principle. The rotation of the pump impeller imparts kinetic energy to the fluid as it is drawn in from the impeller eye (centre) and is forced outward through the impeller vanes to the periphery. As the fluid exits the impeller, the fluid kinetic energy (velocity) is then converted to (static) pressure due to the change in area the fluid experiences in the volute section. Typically the volute shape of the pump casing (increasing in volume), or the diffuser vanes (which serve to slow the fluid, converting to kinetic energy in to flow work) are responsible for the energy conversion. The energy conversion results in an increased pressure on the downstream side of the pump, causing flow.

[edit] Multistage Centrifugal Pumps

Image:Kirloskar multistage centrifugal pump.jpg

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A centrifugal pump containing two or more impellers is called a multistage centrifugal pump. The impellers may be mounted on the same shaft or on different shafts. A multistage centrifugal pump is having following two important functions:

To produce a high head, and
To discharge a large quantity of liquid.

If a high head is to be developed then the impellers are mounted on same shaft (series) while for large quantity of discharge of liquid, the impellers are mounted on different shafts (parallel).

[edit] Footnotes

^ Ladislao Reti, “Francesco di Giorgio Martini's Treatise on Engineering and Its Plagiarists”, Technology and Culture, Vol. 4, No. 3. (Summer, 1963), pp. 287-298 (290)