Abstract: A self-closing vent intended for use in attics, crawl spaces, joist cavities, exterior walls, interior walls, or other structural element which allows for the free flow of air from outside a building to interior spaces during normal use. The vent includes a damper blade pivotally connected to, and disposed within, the vent housing, which is held in an open position by a temperature sensitive fusible link. Two, and preferably three, permanent magnets provide the force for driving the damper blade into a closed and locked position. A first magnet disposed in a side of the vent housing and a second magnet disposed on the damper blade are disposed with opposing (repelling) polarities when the damper blade is held in the open position. A third magnet disposed proximate the back of the vent housing is oriented so as to attract the magnet disposed on the damper blade.

Abstract: A self-closing vent intended for use in attics, crawl spaces, joist cavities, exterior walls, interior walls, or other structural element which allows for the free flow of air from outside a building to interior spaces during normal use. The vent includes a damper blade pivotally connected to, and disposed within, the vent housing, which is held in an open position by a temperature sensitive fusible link. Two, and preferably three, permanent magnets provide the force for driving the damper blade into a closed and locked position. A first magnet disposed in a side of the vent housing and a second magnet disposed on the damper blade are disposed with opposing (repelling) polarities when the damper blade is held in the open position. A third magnet disposed proximate the back of the vent housing is oriented so as to attract the magnet disposed on the damper blade.