The 8100 Series Airfoil Centrifugal Fans utilize the latest design techniques to produce a quiet, highly efficient air mover. Aerodynamically designed airfoil blades and air passages allow more air to be handled with less horsepower and at a lower sound level. This fan has been designed for applications where low operating cost and quiet operation are prime considerations. Features Housing The spiral shaped housing is designed to receive the air leaving the wheel and reduce its velocity with a minimum of turbulence, thereby efficiently converting the velocity pressure to static pressure for increased performance. Wheel Construction Shock-free flow at the leading edge of the blades, plus streamlined flow over the blade surfaces, increases wheel efficiency and quietness.  Wheels have die-formed airfoil blades welded to backplate and rims to provide a particularly rigid assembly. All wheels are statically and dynamically balanced to ensure smooth operation. Bearings Self-aligning, grease lubricated, anti-friction bearings are standard. Minimum starting friction, simple maintenance and long trouble-free life expectancy make them ideal for fan service. In general, ball bearings are used for the higher speeds and roller bearings for heavy loads and at slower speed. Horsepower The horsepower curve is self-limiting and reaches a maximum in the normal selection range at a given speed. Motors selected using this self-limiting power as a basis will not overload as long as the speed is not changed. Options/Accessories Access Doors Extended Lube Fittings Flanged Inlet & Outlet Heat Shield Inlet & Outlet Screens Inlet Boxes Motor & V-Belt Drives Outlet Dampers Shaft & Bearing Guards Shaft Seals Spark Resistant Const. Special Nameplates Std. & Flanged Drains Unitary Subbases V-Belt Drive Guards Weather Covers