Patent ID: 6991536
Filing Date: 2006-01-31
Classification: A62C,F24F

Abstract:
1. A fire damper in a ventilation duct, the damper comprising a flap which is mounted on an axle in the duct to pivot for movement from an open position, allowing air flow along the duct, to a closed position under the action of a biasing force to inhibit air flow or the passage of flame along the duct, wherein a rim is provided on the duct wall, the rim having a rim wall which extends parallel to the duct wall and a flange which extends radially from an end of the rim wall into the duct space to provide a corner where the flange extends inwardly from the rim wall, and the flap has a corner formed at its peripheral edge to mate with the corner of the rim when the flap is in the closed position, wherein the rim wall extends substantially continuously around the inner surface of the duct wall and the flange is planar, and wherein the flap is stepped, whereby the flap peripheral edge on one side of the flap axle mates with one side of the flange, and the flap peripheral edge on the other side of the flap axle mates with the other side of the flange.