Ventilation systems use several main types of fans, each optimised for particular airflow and pressure requirements. The two fundamental categories are axial fans and centrifugal fans, and within these groups there are many sub types designed to suit building ventilation, industrial processes and mining applications.
Axial fans move air roughly parallel to the shaft, like a propeller. Common axial ventilation types include simple propeller wall fans, tube axial fans with cylindrical housings and vane axial fans that add guide vanes to improve efficiency and pressure capability. Propeller fans are suited to short path exhaust or intake through walls. Tube axial fans are used in ducts and tunnels for general ventilation. Vane axial fans provide higher pressure and are often selected as main or booster fans in mines and long duct systems.
Centrifugal fans draw air into the centre of a rotating wheel and discharge it radially into a scroll shaped housing. They are classified by blade shape, such as forward curved, backward curved, backward inclined and radial blade. Forward curved fans are common in air handling units and smaller HVAC equipment, providing high flow at moderate pressure with compact size. Backward curved and backward inclined fans are used in industrial ventilation where higher efficiency and pressure are required. Radial blade fans are robust and handle dust and particles well, making them suitable for dust collectors, material handling and some mining duties.
Beyond these basic categories, there are specialised ventilation fan arrangements. Roof fans and rooftop exhausters are designed to mount on building roofs and discharge air vertically, helping remove heat and contaminants from factories and warehouses. Inline mixed flow fans combine features of axial and centrifugal designs, offering higher pressure than pure axial fans in a compact, duct mountable form. Jet fans for tunnels and car parks create longitudinal airflow without continuous ductwork, using high velocity jets to move air through large spaces.
In the mining industry, ventilation fans are also distinguished by their role in the system. Main fans provide primary intake and return airflow for the entire mine. Auxiliary fans and booster fans supply air to development headings and remote areas. Local extraction fans remove fumes or dust from specific sources such as loading points or crushing stations. Any of these may be axial or centrifugal depending on pressure, airflow, available space and gas or dust conditions.
In summary, the different types of fans for ventilation include axial designs such as propeller, tube axial and vane axial, centrifugal designs with various blade shapes, and specialised units like roof fans, mixed flow fans and jet fans. Selecting the right type requires matching airflow, pressure and environmental conditions to the strengths of each fan category.
