How To Recognize Centrifugal Fans

Fans are used almost everywhere, in both industrial and commercial applications, in handling materials, ventilators, boilers, collecting dust, and refrigeration. The fans of the fans can have a significant effect on the productivity of the plant. Fans are so important, that they are often over-designed, to prevent under-performance, and problems are created that increase the operating costs, while reliability is undermined.

The centrifugal fan was invented in 1832, by a Russian military engineer named Alexander Sablukov, and was used mainly in light industries. Centrifugal fans use a spinning impeller, that moves air in two directions, first radically outwards and then tangentially away from the tips of the blade. Centrifugal Fans will usually have one of 6 different wheel types that pull the air into the inlet of the housing, push the air through the wheel, and discharge it at an angle of 90 degrees, through the discharge unit of the assembly.

Centrifugal fans are capable of generating relatively high pressures as the air moves outward from the impeller hub to the tips of the blade. They are often used in heavy environments that contain a high amount of moisture and particulates. The wheel is the most important component of the fan and the design determines the performance. The term squirrel cage fan and blower are often interchanged, because the configuration resembles a hamster wheel. The kinetic energy generated by the rotating blades is used to increase the pressure of the air stream, which is then used to over the resistance of the dampers, ducts and other components.

There are six predominant wheel-designs that all serve different purposes and are used in different situations:

Shrouded Radial Blade blower wheels are used for delivering high volumes of air under high pressures, and are used in blow-off systems, with extended piping or duct work.

The Centrifugal fans that use Open Radial Blades with Back Plate blower wheels are used in the transport of granular or powdery material and fibers. An alternate design that can also be used for the transfer of granular material is the Open Paddle Wheel, which contains no back plate.

In the Backward Inclined wheels design, flat plates are attached around the circumference of the plate in the same configuration of an airfoil or the wing of an airplane. They are used for common ventilation, in HVAC systems, and in the dust collection.

Forward Curve Multi-vane wheels are used for transferring larger volumes of the air at slight pressures, and are also used in HVAC units that operate at the slower speeds.

The final wheel configuration is the Backward Curved Radial blower wheel, which is actually a modification of the Open Radial Blade wheel, but the performance is much improved performance. It can really be used for conveying granular material.

There are two types of centrifugal fans. They can be installed either inline in the ductwork, or alternatively, they can be mounted on a wall. It can sometimes be difficult to differentiate the axial fan from, the centrifugal fan, but there is normally a huge price difference between the two.

Centrifugal fan is found in all industrial applications that requires the movement of air or articles. The centrifugal fan that you need will be determined by the intended purpose.