Centrifugal pumps are fairly simple in nature. They use the kinetic energy of a motor to move liquids. An engine is attached to the axis, which then rotates the pump impeller, which is reminiscent of an old ship’s “water wheel”. The rotation moves the water from its entry point through the casing, and finally to the exit.
While most pumps are used for water, centrifugal pumps are also used for sewage, petroleum, and chemicals. Incidentally, the reverse of this process is called a water turbine. The impeller is placed in moving water; it can be used as a water turbine which converts the water’s energy into rotational energy. In other words, instead of the motor moving the pump to move the water, the water moves the pump to move the motor.
Because of the direct conversion of the motor to rotational energy, the centrifugal pump is a very simple pump. As with all pumps, there are advantages and disadvantages.
The biggest advantage of centrifugal pumps is their aforementioned simplicity. They don’t require any valves, or many moving parts. This makes them easy to produce with many different materials. It also allows them to move at high speeds with minimal maintenance. Their output is very steady and consistent. Most of all, they are very small compared to other types of pumps that create the same output.
The main disadvantage is that they use rotation instead of suction to move water, and therefore have almost no suction power. This means that a centrifugal pump must be put under water, or primed, before it will move water.
Centrifugal pumps can also develop a phenomenon called “cavitation”. This happens when the speed of the water causes it to vaporise, which causes bubbles in the liquid. A combination of the speed of the vapour bubbles and the implosion of vapour bubbles can be corrosive to the impeller surfaces and pump casing.
For most household or light industrial uses, a centrifugal pump is fine. As long as the liquids aren’t too viscous, like mud or waste, and the pump can be totally submerged, it will provide consistent, effective, and reliable operation. Centrifugal pumps provide a lot of flexibility, are easy to move, and don’t take up a lot of space.
For a wide selection of centrifugal and other pumps, browse through the Pump Solutions Australasia website.