Centrifugal fans are industrial blowers that move air by means of a rotating impeller and a scroll-shaped housing, discharging the air radially at higher pressure than typical axial fans. They are widely used in factories, power plants, chemical plants and mines wherever air must be pushed through ducts, filters and process equipment.
In a centrifugal fan, air enters the centre of the impeller along the shaft and is then flung outward by centrifugal force as the impeller spins. The scroll housing collects this radial flow and converts part of the kinetic energy into static pressure. This design allows centrifugal fans to generate moderate to high static pressure, making them ideal for systems with significant resistance, such as dust collection, scrubbers, complex ductwork and underground airways.
Centrifugal fans are classified by blade shape and duty. Radial blade fans have straight blades and are robust for dusty, abrasive air and material handling. Backward-curved and airfoil fans offer high efficiency for clean or lightly dusty air at medium to high pressures. Forward-curved fans are used mainly in HVAC units at lower pressures. Within these categories, fans can be further specialised for high temperature, corrosion resistance or explosion protection.
Compared with axial fans, which move air parallel to the shaft and are well suited to high-volume, low-pressure duties, centrifugal fans excel in ducted systems that need higher pressure and controlled distribution. In mining ventilation, they are often used for dust extraction, local exhaust at crushers and loading points, booster systems and certain main ventilation duties where airway resistance is high.
Centrifugal fans are driven primarily by electric motors, either directly or via belts and pulleys. Performance is described by fan curves showing the relationship between airflow, pressure, power and efficiency at different speeds. Engineers use these curves, together with system resistance data, to select the right fan size and type for each application.
In summary, centrifugal fans are engineered blowers that draw air into a rotating wheel and discharge it radially into a scroll housing, producing the pressure needed for industrial and mining ventilation systems. Their ability to handle higher pressures and harsh conditions makes them indispensable in many critical air-moving applications.
