An intake fan is a fan whose main job is to draw fresh air into a space. While exhaust fans pull contaminated or hot air out, intake fans act as supply fans, bringing in outdoor air or air from a clean zone and delivering it to the area that needs ventilation. Together, intake and exhaust fans form a complete air circuit that maintains air quality, temperature and pressure in buildings, industrial plants and underground mines.
In a simple mechanical ventilation system, an intake fan pulls outside air through filters and, if necessary, heating or cooling coils. The fan then pushes this conditioned air into the building through ducts and diffusers. This supply air replaces the stale air being removed by exhaust fans in toilets, kitchens, workshops or process areas. By adjusting the balance between intake and exhaust, engineers can create a slight positive pressure in clean zones so that air flows outward through doors and leaks, preventing dust, fumes or odours from entering.
In industrial environments, intake fans are used to supply large quantities of outdoor air to production halls, steel mills, chemical plants and other facilities where significant heat or contaminants are generated. Fresh air is often introduced at low level or through displacement diffusers, allowing it to rise as it warms and carry heat and pollutants towards high-level exhaust points. Properly designed intake systems ensure that workers receive a reliable flow of clean air and that process equipment has enough combustion or dilution air.
In underground mining, intake fans play a critical role in the main ventilation system. Air enters the mine through intake shafts, declines or drifts and is pushed or pulled by main fans arranged as intakes or exhausts. When a fan is used as an intake fan, it pressurises the intake airway and drives air towards the workings. Auxiliary intake fans can also be installed on surface or underground to push fresh air through ducting into blind headings, development ends and refuge chambers.
Intake fans may also be used to cool electrical rooms and equipment enclosures. In these cases, the intake fan pulls cooler air from outside or from a clean corridor and delivers it directly across heat sources such as variable-frequency drives, transformers and switchgear. Exhaust openings or small exhaust fans then allow warm air to escape, maintaining safe operating temperatures for sensitive equipment.
In summary, an intake fan supplies air rather than removes it. It draws in fresh, usually filtered air, pressurises the space or duct system and works together with exhaust fans to maintain the desired airflow pattern, temperature and pressure in industrial buildings and mines.
