During the continuous drying phase of a paper machine, cooling fans maintain the thermal balance of the drying cylinders. These fans are mounted directly on the cylinder housings or on adjacent ductwork, where they draw in ambient air and direct it across the cylinder surfaces. The airflow prevents overheating, ensuring uniform moisture removal from the paper web and protecting the cylinder bearings from thermal stress. In high-speed machines, the fans also help stabilize the boundary layer of air around the web, reducing the risk of sheet flutter or wrinkling before the calendering stage. When maintenance crews perform roll changes or bearing inspections, the same fans are often temporarily repositioned to ventilate confined spaces, improving worker safety in areas where heat and humidity accumulate. In adjacent sectors like steel production, similar cooling fans serve comparable roles on annealing lines, where controlled airflow prevents warping of metal coils during cooling.