Columnist Bob Pelikan continues his series on the inner workings of pump systems.
A simple way to in-crease pressure is to stack pumps, hooking them in series, with the outlet of the first connected to the inlet of the second pump. When stacking pumps, each one adds its pressure capability to that of the one before it so the total pressure capability of the stack is the sum of the pressures of all the pumps. This was a common practice before multi-stage centrifugal pumps became readily available. A multi-stage pump has more than one impeller/diffuser set (a stage) in one housing, driven by a single motor (See Figure 1).