10th Jan 2022
Centrifugal pumps

Pumps often have the label as either centrifugal or positive displacement. But, you have probably heard of rotodynamic pumps which is often incorrectly interchanged with the word centrifugal pumps. So is there a difference between rotodynamic pumps and centrifugal pumps? The short answer is yes, there is a marked difference, but let us explore further.

Rotodynamic pumps include a rotating part (such as an impeller, rotor or propeller). This imparts mechanical energy on a fluid so increasing the kinetic energy of the fluid that is then converted to potential energy (pressure) in the pump casing. There are generally three types of impeller / rotor / propeller and the following illustrates the differences and directions of flow of each type.

.Centrifugal pumps

Figure (a) You can see that in the fluid is taken in through the impeller eye and accelerated at an angle of 90 degrees (radially). This is a radial or centrifugal impeller.

Figure (b) shows the fluid taken from the eye and accelerated at an angle, so this a mixed flow pump.

Figure (c) shows the liquid being accelerated along the pipe, or axially, so this is an axial flow machine.

So only figure (a) shows a centrifugal impeller from which we can conclude the question is there a difference between centrifugal and rotodynamic pumps?  Well, all centrifugal pumps are rotodynamic. But not all rotodynamic pumps are centrifugal.



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