Centrifugal Fans

Centrifugal fans also known as radial fans are the most common type of fan in use today. The principle of operation, albeit relatively simple, has evolved over the years with machines now capable of high aerodynamic efficiency and with significant powers.

In a centrifugal (or radial) fan the rotation of the impeller causes the air to travel through it in a radial direction, developing pressure as it does so. The impeller, which does most of the work within the fan, and located in the centre of the casing, are all of a similar shape. A sketch of a large aerofoil bladed centrifugal fan is shown below.

Centrifugal fans may be single or double inlet. A double inlet impeller consists of two single inlet impellers back to back on the shaft sharing a common backplate, providing almost double the flow of a single inlet fan.

Output can be controlled by variable vanes in the casing close to the impeller inlet - inlet vane control, or by a louvre damper in the fan inlet box - box vane control.

 

 

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