What is the difference between series and parallel connection of centrifugal pumps?

Centrifugal pumps in series and parallel are two different piping connections, the difference is as follows:

Series: that is, a number of centrifugal pumps are connected to the same piping in turn, the outlet of the previous pump is connected to the inlet of the next pump. This way you can superimpose the heads of different pumps to increase the total head, but the flow rate is unchanged, applicable to the water level height, flow demand is smaller occasions.

Parallel: that is, a number of centrifugal pumps connected to the same pipeline at the same time, their imports are connected to the export of different parts of the pipeline into. This way you can superimpose the flow of different pumps, thus increasing the total flow, but the head remains unchanged, suitable for the water level height is low, the flow demand is larger occasions.

It should be noted that, in the selection of centrifugal pumps in series or parallel, you need to consider the performance parameters of the pump, the pressure loss of the piping system and the flow rate changes and other factors to ensure the normal operation of the pump and the stability of the system.