1. Centrifugal fans displace air radially, changing the direction ( typically by 90?) of the airflow.2. Since 200�F air weighs only 80 % of 70�F air, the centrifugal fan will create less pressure. 3. Two are more common : " centrifugal fan scrubbers " and " mechanically induced spray scrubbers ". 4. The centrifugal fan is a drum shape composed of a number of fan blades mounted around a hub. 5. Another type of vertical axis is the Parallel turbine, which is similar to the crossflow fan or centrifugal fan . 6. Since air weighs only 80 % of air, the centrifugal fan will create less pressure and require less power. 7. The centrifugal fan will displace a constant volume of air in a given system regardless of the air density. 8. Common uses include water, sewage, petroleum and petrochemical pumping; a centrifugal fan is commonly used to implement a vacuum cleaner. 9. Ventilation is accomplished partly by opening the windows, and partly by a forced-air system served by 2 twin centrifugal fans . 10. Air density corrections need to be taken into account for centrifugal fans that are specified for continuous operation at higher temperatures.