Types of Centrifugal Fans & Their Characteristics

As mentioned in our previous article about axial fans, there are generally two classifications of fans: centrifugal flow fan and axial flow fan. How they are differentiated is essentially how air flows through their impellers. In centrifugal fans, the air enters the impeller axially and is accelerated by the blades to be discharged radially. In axial fans, air is accelerated by rotational force. Below, we cover the different types of centrifugal fans and their specific characteristics and uses.

Types of Impellers

The blade configurations of centrifugal fans are classified into three types: forward curve, backward inclined, and radial or straight blade. Each type has a unique application and purpose.

Forward Curve Fans

Forward curve fans have impeller blades that are small and numerous with a heavy curve and short chord length. The blade curvature faces the direction of rotation, operating at relatively low speeds and pressures. These fans are sometimes known as volume blowers, designed to deliver high air volumes against lower static pressures. Their light construction results in a cost effective fan with quiet operation.

The forward curve fan is ideal for applications in refrigeration, domestic boilers, and warm air heaters, among others.

Backward Inclined Fans

Backward inclined fans are sometimes known as “non-overloading” fans. With larger and heavier blades than forward curve fans, their blades are also inclined away from the direction of rotation.

Backward inclined fans are used to deliver medium to high airflow at higher static pressures. This type of fan is used primarily in industrial applications for ventilation, large commercial heating and cooling units, and fume extraction systems, among others.

Radial Blade Fans

Two common names for radial blade fans are “steel plate” or “paddle impeller” fans. Radial blade impellers are typically narrower and heavier than forward curve and backward inclined fans. The design of this type of fan is ideal for high-pressure applications. Their rugged construction lends to more harsh environments, including those in mines, factories, and commercial buildings, among others.

Aerotek Equipment offers a wide variety of high quality centrifugal fans to suit your unique air movement needs. Whether you need backward inclined fans for heat recovery systems, high pressure condensing boilers, gas burner systems, or other airflow needs, we have the ideal solution. Contact us today to discuss your air movement needs.