Damper blade seal

A damper assembly comprising:

• a. a generally rectangular and generally planar damper blade adapted to divide a current of air between an upstream and a downstream side, said blade being rotatable about a longitudinal axis between an open and closed position and including two generally similar flat longitudinal blade edges that generally describe a cylinder as said blade is rotated, said flat longitudinal edges extend generally perpendicular to said generally planar damper blade, said longitudinal blade edges being positioned substantially between and adjacent to a first and second edge when said damper blade is in said closed position;
• b. a first seal attached to one of said longitudinal blade edges such that said first seal tends to urge said damper blade to said closed position under the impetus of a pressure differential between said upstream and downstream side, said first seal including a first flexible lip extending toward said upstream side and sealing in sliding contact against said first edge to provide a wiping action in a direction generally tangent to said cylinder as said damper blade comes to rest at said closed position and to exert a radial sealing force against said first edge in a direction generally parallel to said generally planar damper blade when said blade is closed;
• and
• c. a second seal attached to said second edge and having generally the same cross-sectional profile as said first seal, said second seal including a second flexible lip extending generally upstream in sliding contact against an other longitudinal edge of said blade to provide a wiping action in a direction generally tangent to said cylinder as said damper blade comes to rest at said closed position and to exert a radial sealing force against said other longitudinal edge in a direction generally parallel to said generally planar damper blade when said blade is closed.