This wheel is like a paddle wheel, with or without side rims. The blades are perpendicular to the direction of the wheel’s rotation and the fan runs at a relatively medium speed to move a given amount of air. The radial blade fan is designed for material handling applications and is also used for high pressure requirements, generally the least efficient of the centrifugal fans.
The wheel's blades are flat and lean away from the direction of the fan wheel’s rotation. This fan is used in industrial applications where efficiency at a good value is important. This fan type is more efficient then the radial blade fan. The fan horsepower curve is non-overloading.
The backward curved fan is similar to the backward inclined fan but the blades are curved slightly. The backward curved fan is quieter, more efficient than the BI fan and capable of higher pressures. The fan horsepower curve is non-overloading.
The airfoil fan is the most efficient and quietest of the centrifugal fans. It is used in many industrial applications where energy savings are important. The fan horsepower curve is non-overloading. The blades are a hollow design and can be made with special construction for clean air applications.