The main purpose of a centrifugal fan is to provide airflow at relatively high static pressure so that air or gas can be pushed or pulled through ductwork, filters, heat exchangers and other process equipment with significant resistance. In many industrial and mining applications, centrifugal fans—often called blowers—are chosen instead of axial fans when the ventilation or process system has high pressure losses, contains dust or needs a more stable performance curve over a range of operating conditions.
A centrifugal fan works by drawing air in along the shaft, accelerating it through a rotating impeller and then discharging it radially into a volute casing. This change in direction, combined with centrifugal force, converts mechanical energy from the motor into pressure energy in the air stream. As a result, centrifugal fans can achieve higher static pressures than axial fans of similar size and are better suited for systems with long ducts, multiple fittings, filters, scrubbers or cyclones.
In industrial ventilation, the purpose of a centrifugal fan is often to extract contaminated air from processes. Examples include dust collection systems for grinding and crushing, fume extraction from furnaces and welding bays, and exhaust from kilns, dryers and ovens. Centrifugal fans can be designed with rugged radial blades and wear-resistant materials so they can handle particles and abrasive dust without excessive erosion.
In power plants and metallurgical operations, centrifugal fans serve as ID (induced draft) and FD (forced draft) fans around boilers and furnaces. FD fans force combustion air into the boiler, while ID fans pull flue gas through heat-recovery and gas-cleaning equipment to the stack. In these roles, centrifugal fans must handle hot gases, corrosive components and varying load conditions while maintaining stable draft and efficient combustion.
Within mining ventilation systems, centrifugal fans are used where higher pressure is needed than axial fans can easily deliver. This includes some main fan installations on deep or high-resistance mines and specific branches where air must be forced through dense bulk air coolers, spray chambers or long rough airways. Their ability to maintain pressure with changing system resistance makes them valuable in complex networks.
Another purpose of centrifugal fans is to provide precise controllability and safety. Because their performance curves are generally more stable than those of axial fans, they can be easier to control using dampers or variable speed drives without encountering stall or surging. In hazardous or explosive atmospheres, centrifugal fans can be built with ATEX or other explosion-proof certifications, with carefully designed casings, clearances and non-sparking materials.
In summary, the purpose of a centrifugal fan is to deliver airflow at the higher pressures required for ducted, filtered and process-laden systems, making it essential for dust collection, boiler draft, fume extraction and high-resistance ventilation circuits in mining and heavy industry.
