Pumps in series :
A number of impellers are mounted in series or on the same shaft for obtaining a high head.
The discharge from impeller passes through a guided passage and enters the second impeller.
At the outlet of second impeller the pressure of water will be more than the pressure of water at the outlet of first impeller.
The arrangement of pumps in series employed for delivering a relatively small quantity of liquid against very high heads.
When a large quantity of liquid is required to be pumped against a relatively small head then two or more pumps are applied which are arranged in parallel as shown in Fig. given below.
Each of these pumps working separately lift the liquid from a common sump and delivers it to common collection pipe through which it is carried to the required height.
If Q is the discharge capacity of one pump and there are n identical pumps operating in parallel then the total discharge is given by, QT =nxQ.
