With centrifugal fans, it is usual for the direction of the air flow to change by an angle of 90 degrees. Free running impellers and scroll fans differ in that scroll fans require a volute casing to generate pressure.
Centrifugal fans are used for higher pressures and medium air volume flows. They are also used in ducted applications. Centrifugal fans provide great versatility in ventilation, cooling and air conditioning applications.
