Centrifugal pumps are used to transport fluids by converting rotational kinetic energy from the engine to the hydrodynamic energy of the liquid. Centrifugal pumps are commonly used for pumping water, sewage, agriculture processes, and so on. They are a low pressure type of pump and are much preferred due to their relative ease of use. Centrifugal pumps are also very low maintenance and cost effective.
The major part of a centrifugal pump is the impeller which consists of curved vanes placed between two discs. Impellers with two discs and curved vanes are referred to as enclosed impellers while those with only one disc are called semi-open impellers. Centrifugal pumps with semi-open impellers are usually better suited for transporting liquids that contain some solids in them.
The general structure of a centrifugal pump is like that of a basic standing fan, with the vanes looking like fan blades. The rotational movement of the impellers forces the fluid out faster, into the pump casing.
Another part of the centrifugal pump is the pump casing, which has two types. The pump casing can either be a volute pump casing or diffuser pump casing. Volute pump casing has a curved design which causes increased pressure as the fluid comes out towards the outlet. In the diffuser pump casing design, the pressure increases as the fluid passes through the impellers.
In cases where the liquid is high viscosity or contains some solid particles, the volute pump casing is most suitable, but it opens up the impeller to quicker wear and tear. The diffuser case pump is more efficient due to its flexibility.
Due to the speed at which its impeller rotates, a centrifugal pump becomes less efficient when used for high viscosity liquids. Centrifugal pumps are susceptible to corrosion and wear-and-tear depending on the nature of the liquids that it is used to pump. Centrifugal pumps need to be primed before they can start working as they cannot function when dry.
Some of the types of centrifugal pumps include canned motor pump, magnetic drive pump, circulator pump, chopper pump, slurry pump, cryogenic pump, trash pump, multistage pump.
The canned motor pump has the impeller directly attached to the rotor of the motor. It is most suited for pumping chemicals and hydrocarbons that are not allowed to leak. The magnetic drive pump is suitable for the same application as the canned motor pump, but the difference is in the position of the impeller. The impeller of the magnetic drive centrifugal pump is held together by magnets.
The impeller of the chopper grinder pumps has teeth for grinding solids. This type of impeller makes the chopper grinder suitable for use in food processing and sewage plants.
The circulator pump is a simple type of centrifugal pump that is most suitable for air conditioning , ventilation and heating.
Another unique type of centrifugal pump is the multistage pump which has multiple impellers, making it suitable for high pressure pumping.
The cryogenic pump is mostly suitable for coolants due to its special ability to function under low temperatures.
Trash pump is a centrifugal pump that is suitable for pumping water containing solid waste. The slurry pump is also another pump that can withstand pumping water containing abrasive solid particles.
Centrifugal pumps are a cost effective but efficient type of pump that is mostly suitable for low viscosity liquids.