VENTILATION FAN WITH FIREPROOF DAMPER AND WEATHER COVER WITH FIREPROOF DAMPER FOR VENTILATION FAN

摘要

PURPOSE: To provide a ventilation fan which enables the closing of an air path accurately with a fireproof damper even when a fan rotates to generate an air current CONSTITUTION: As temperature in an air path 30 rises, a thermal fuse 28 burns out and a damper 24 loses a support. The damper 24 turns in the direction of closing the air path 30 by a dead load. At the same time, a lever 26 contacting the rear of the damper 24 receives a moment by the own weight and an energizing force of springs 48 and 50 applied between the tip of the lever 26 and the tip of the damper 24 to generate a force for pushing the damper 24 from the rear thereof. The force increases as the damper turns in the direction of closing and is allowed to resist a force by an air current generated with a fan 18.