MULTISTAGE CENTRIFUGAL PUMPS
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. For higher pressures at the outlet, impellers can be connected in series. For higher flow output, impellers can be connected parallel.
The multistage centrifugal pumps are those which have two or more identical impellers mounted on the same shaft or on different shafts. They are used to produce high heads or to discharge a large quantity of liquid. In order to obtain a high head, a number of impellers are mounted in series or on the same shaft while to discharge a large quantity of liquid, the impellers are connected in parallel.
About Multistage Centrifugal Pumps
Multistage centrifugal pumps have multiple liquid chambers (or stages) that are connected in series. Fluid enters the first chamber at suction line pressure and leaves at some elevated pressure. Upon leaving the first stage, the fluid enters the second stage where the pressure is increased further.
The more stages the pump has, the higher the final discharge pressure. These pumps have the unique ability to produce higher and higher pressures with the addition of every stage, but flow range always remains constant for a given rpm.
There are a couple different types of multistage pumps. Those with a horizontal shaft, and those with a vertical shaft.