Fluid Mechanics for Chemical Engineering

Chapter 5

Pumps

This chapter is basically meant for pump users, i.e people who need to select a pump for a specific use. This requires an ability to identify the characteristics of the pumping work to be carried out (like what flow rate? what head? etc), to choose a suitable type of pump of the required size and, lastly, some knowledge of the precautions and difficulties involved in operating such devices in order to optimize their usage.

Engineers will not find in this chapter the tools required to design a pump. Nevertheless, the operating principles of each type of pump are described, as this is necessary to grasp the intricacies of the various issues mentioned above.¹

With reference to classical applications of hydraulics, chemical engineering, and process engineering, two categories of pumps are presented in this chapter:

1. Turbo pumps, which are devices comprised of a rotor provided with blades. Within this category, centrifugal pumps and axial pumps are discussed. These two types of pumps lie at either end of the operating range of turbo pumps. Axial pumps allow for large flow rates in conditions where the head to be imparted on the fluid is small. Centrifugal pumps allow for smaller flow rates while imparting a larger head on the fluid.

2. Positive displacement pumps and peristaltic pumps, which are more particularly used in situations where it may be necessary to provide a large head increase at low and controlled flow rates.

5.1. Centrifugal pumps

5.1.1. Operating principle ...