Overheat protection appts for smoke removal fan - uses duct enclosing drive belt to carry external air to cool belt transmission and to cool motor and fan

摘要

The fan (5) is driven by a motor (6) through a belt and pulley transmission (7). The fan, motor and transmission are all inside a duct (1) that has an inlet for the gasses that are to be removed from a room, and an outlet to exhaust these gasses to the exterior of the building. An inlet is provided for cooling air that is drawn from the exterior, and is directed through the enclosure (30) that protects the belt and pulley transmission, onto the motor and the fan bearings. ADVANTAGE - Allows longer operating time for fans intended to draw smoke out of a building in the event of fire.