Industrial Fans
Below are six of the more popular design of industrial fans:
Axial-Centrifugal Fans
These fans are also called 'Tubular Centrifugal Fans, in-line centrifugal fans', or 'Mixed-flow fans' (especially if the fan wheel has a conical back plate). The following two types of fan wheels are used in these fans:
1. A fan wheel with a flat back plate, the same type as is used in a scroll housing. When used in an axial-centrifugal fan, however, the air stream has to make two 90 degree turns, which, of course, results in some extra losses, especially if the diffuser ration (housing i.d./wheel o.d.) is small.
2. A fan wheel with a conical back plate. This fan wheel is more expensive to build, but the air stream here has to make only two 45 degree turns, a more efficient arrangement. In either case, the fan wheel usually has BI blades or occasionally AF or BC blades.
The following three types of housings are in common use in axial-centrifugal fans:
1. A cylindrical housing
2. A square housing
3. A barrel-shaped housing
Various wheel housing combinations are possible. Barrel-shaped housings have a separate chamber for the motor so that a direct drive can be used, even if hot or corrosive gases are handled. This style of fan has the trade name 'Axcentrix Bifurcator', implying that the air stream is divided into two forks, flowing above and below the motor chamber but never coming into contact with the motor.
|