AXIAL
FANS - Air is moved
through the fan in an axial direction. High flow very low pressure
development.
BACKWARD
CURVED CENTRIFUGAL
- Air enters the eye of the impeller drawn in by the suction
side of the blade. Less flow than axial but more pressure development.
FORWARD
CURVED CENTRIFUGAL
- Generates more air volume and higher static pressure than
backward curved of the same size but at the expense of lower
efficiencies. The scooping action of the forward curved generates
a high air velocity which in turn give a high dynamic pressure.
The fan scroll converts this into static pressure.
MIXED FLOW
FAN - A compromise
between an axial and backward curved centrifugal. Axial throughput
but with the performance of a backward curved.
TANGENTIAL
FAN- These move
air in a strange manner. Air exits in a similar way to a centrifugal
fan but air enters the impeller through the blades.
