About Centrifugal
Centrifugal fans consist of an impeller in a casing having a spirally shaped contour. The air enters the impeller in an axial direction and is discharged at the impeller outer periphery. The air flow moves along the centrifugal direction (or radial direction). Sometimes centrifugal fans are called radial flow type fans. Centrifugal fans are capable of generating relatively high pressures. They are suitable for high pressure applications as compared with axial flow fans. Generally centrifugal fans have three types of blade: forward blade, backward blade and radial blade.
The centrifugal fan is not reversible, so there are five different types of centrifugal fans, which differ based on the type and shape of the fan blades.
Radial
These are high-pressure fans with medium airflow. Radial-bladed fans are best for industrial applications where there is dust or in environments where there is gas or moisture in the air.
Forward Curve
These are medium pressure, high airflow fans that can be used in both clean air, ventilating and exhaust applications.
Backward (curved & inclined)
These are high-pressure, high flow, high efficiency fans. Power reduces as flow increases over the most efficient area of the system.
Airfoil
These are the highest efficiency fans, best in clean air applications.