Centrifugal fans are classified into three main types based on the shape of their impeller blades: Forward-curved, backward-curved, and radial.
Forward-curved blade fans (such as multi-blade types) are characterized by their compact size and high airflow, but have lower efficiency (approximately 65-75%), and are commonly used in air conditioning or low-pressure ventilation systems;
Backward-curved blade fans have an efficiency of 80-92% and are suitable for medium to high-pressure applications such as boiler induced draft; radial blade fans have a simple structure and strong wear resistance, and are often used for conveying dust-laden gases.
In addition, they can be classified into low-pressure (<1 kPa), medium-pressure (1-3 kPa), and high-pressure (>3 kPa) fans based on pressure rating.
Special types also include explosion-proof fans (using copper impellers and explosion-proof motors), corrosion-resistant fans (such as those made of fiberglass), and high-temperature fans (with built-in cooling systems or ceramic coatings). Selection requires comprehensive consideration of airflow, pressure, media characteristics, and installation environment.