A centrifugal fan is a mechanical device for moving air […]
A centrifugal fan is a mechanical device for moving air or other gases. The terms "blower" and ..... methods for conducting laboratory tests on housed fans to determine airflow rate, pressure, power and efficiency, at a given speed of rotation.
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.
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.
Centrifugal Fan - http://www.afl-fan.com/