ABSTRACT
There exists a wide variety of pumps that are designed for various specific applications. However, most of them can be broadly classified into two categories: positive displacement and centrifugal. The primary performance variables for any pump are the pump capacity and the pressure or "head" that the pump can develop. The term positive displacement pump is quite descriptive, because such pumps are designed to displace a more-or-less fixed volume of fluid during each cycle of operation. They include piston, diaphragm, screw, gear, progressing cavity, etc. The term "centrifugal pump" is a very descriptive term, since these pumps operate by the transfer of energy from a rotating impeller to the fluid, which is normally inside a casing. The kinetic energy and momentum of the fluid are increased by the angular momentum imparted by the high-speed impeller. This kinetic energy is then converted to pressure energy in a diverging area between impeller discharge and the casing before the fluid exits the pump.
