Types of Fans - Capacity Ranges
Centrifugal, axial and propeller fans and their capacity ranges.
Common types of fans and their characteristics are summarized in the table below:
| Fan Type | Wheel Type | Static Pressure (in H2O) | Wheel Diameter (in) | Air Flow (cfm) | Break Horse Power (bhp) |
|---|---|---|---|---|---|
| Centrifugal | Backward Inclined | 0 - 12 | 10 - 75 | 500 - 125000 | 0.33 - 200 |
| Backward Inclined Airfoil | 0 - 14 | 20 - 120 | 1500 - 450000 | 0.33 - 1500 | |
| Propeller Axial | Direct Drive | 0 - 1 | 10 - 50 | 50 - 50000 | 0.17 - 10 |
| Tube Axial | Direct Drive | 0 - 1 | 20 - 50 | 2500 - 50000 | 0.33 - 15 |
| Tubular Centrifugal | Backward Inclined | 0 - 10 | 10 - 110 | 500 - 350000 | 0.33 - 750 |
| Vane Axial | Direct Drive | 0 - 5 | 20 - 60 | 1200 - 150000 | 0.33 - 150 |
- Centrifugal - flow within the fan is mainly radial to the shaft
- Axial - flow within the fan is mainly parallel to the shaft
Centrifugal Fans
The centrifugal fans operates by throwing air away from the blade tips. The blade wheel are mounted in housing and the blades can be forward curved, straight, or backward curved.
Backward curved blades are generally more efficient but forward curved blades are more "self-cleaning" and should be used in applications with high dust-concentrations, or where materials are conveyed by the air.
The centrifugal fans are preferred before axial fans where high airflow rates and high static pressures are required.
Axial Fans
Tube-axial fans consists of propeller-shaped blades and a drive motors mounted in tubes. The fans are in general build to be implemented in the duct work.
Vane-axial fans are variations of the tube-axial fans with air straightening vanes added in front of or behind the propeller blades.
A propeller-axial fan consists of a a propeller-shaped blade and a drive motor mounted on a flat frame. The construction is often build to be installed in a wall or located individually in the room.
