From Custom Built Fans
Axial fans are suitable for large quantities of air at low pressures. They are relatively cheaper than centrifugal fans. They are easily installed in round ducts and has a reduced space requirement, thus lowering the cost of the system. The impeller has adjustable blades which make it possible to adapt the fan to the requirement changes. Impellers can be supplied in polypropylene, aluminium , mild steel or stainless steel. Belt driven axial fans are used in situations where it is important that the motor is kept out of the airstream due to high temperature or the corrosive nature of the gases/fumes involved. Bifurcated Fans are direct driven axial fans where the motor is encased in a metal box to isolate it from the airflow.