Backward Inclined Fan Rotation

The name centrifugal fan is derived from the direction of flow and how the air exits the fan impeller radially from the outer circumference of the fan.

Backward inclined fan rotation.

How does backward curved centrifugal fan work. Backward curved blades as in figure 3 b curve against the direction of the fan wheel s rotation. Deep blades allow efficient expansion within blade passages. 10 to 16 single thickness blades curved or inclined away from direction of rotation.

Air leaves impeller at velocity less than tip speed. Larger backward inclined curved blowers have blades whose backward curvatures mimic that of an airfoil cross section but both designs provide good operating efficiency with relatively economical construction techniques. In the example shown below the fan rotates in a clockwise direction. Efficiency only slightly less than airfoil fans.