In series operation of pumps, how is the combined performance curve determined?

In series operation of pumps, the combined performance curve is determined by adding the heads vertically at the same capacities. This method reflects how pumps are designed to work together when placed in series. When pumps are connected in this manner, the discharge remains constant while the total head produced by the system is the sum of the individual heads generated by each pump at a given flow rate.

For example, if you have two pumps that each generate a specific head at a certain flow rate, the total head available to the system will be the sum of these heads when both pumps operate simultaneously. This approach leads to a resultant curve that demonstrates how the head increases with the same flow rate, differentiating it from parallel operations, where capacities would be combined horizontally rather than vertically. This concept is crucial in plumbing design as it helps engineers understand how to effectively configure pumps to meet specific system requirements.