Page 72 - Know and Understand Centrifugal Pumps

Pump Classification

0 FLOW

Fiaure 6-5
toward increasing the flow and speed. A more realistic curve would
appear as in Figure 6-5.

Conce p tu a I d iff ere n ce

This is the conceptual difference between centrihgal pumps and
positive displacement pumps, as you can see when we superimpose the
four theoretical and realistic curves (Figure 6-6).
Upon developing the system curve, the pump curve will always
intersect the system curve, it doesn’t matter about the pump design.
We’ll see this later in Chapter 8.
According to Figure 6-1, entitled Pump Classification, approximately
half of all existing pumps are centrifugal, and the other half are PD-
pumps. Actually, it’s possible that there are more PD pump designs
than centrifugal pump designs, and a higher population of PD pumps
in the world for specific applications, than centrifugal pumps in general
applications.
However, in heavy industry, meaning metallurgical (steel and
aluminum) processes, mining, petroleum refining, pulp and paper
production, and the process industries like chemical and pharmaceutical
production, potable water, wastewater, edible products, and manu-