Centrifugal fan is mechanical devices for moving air or gas. A fan wheel mounted on a hub inside the casing contributes to the movement. The fan wheel is rotated by an external force (electric motor or internal combustion engine). The fan consists of blades or ribs arranged around the hollow hub. The air or gas to be moved enters the housing through the side of the fan wheel into the hollow hub and then turns 90 degrees to flow through the fan blades. The AC Backward Curved Centrifugal Fan is then named by accelerating the air by applying centrifugal force to it. Accelerated air or gas then leaves the shell.
These fans are able to move the air at higher pressures, making it ideal for use in pollution control systems, central cooling or heating systems, and as dual inlet fan in inflatable structures.