Patent ID: 7216898

Claim:
A flanged ring used as a connector to join double wall circular ducts in HVAC systems, the double wall ducts having an outer duct and a structurally separate inner duct disposed within the outer duct, the flanged ring comprising: a first generally cylindrical-shaped ring composed of from 10–20 gauge metallic material, said first ring having a cross section with: an exterior mating flange defining a first annular mating face, said exterior mating flange defining an outer perimeter and an inner perimeter; an outer insertion flange extending laterally from the inner perimeter of the exterior mating flange and having an inside surface and an outside surface, said outer insertion flange having sufficient length to allow a fixed, direct attachment to an outer duct of a double wall circular duct, said outer insertion flange extendable unobstructedly beyond a fixed attachment to an outer duct and substantially concentric to an outer duct; an exterior hem that is substantially concentric to the outer insertion flange, said exterior hem extending outwardly from the outer perimeter of the exterior mating flange to overlap at least a portion of the outside surface of the outer insertion flange; the outer insertion flange, the exterior mating flange and the exterior hem collectively formed as a singular structure comprising the first ring; and a second generally cylindrical-shaped ring composed of from 10–20 gauge metallic material, said second ring having a cross section with: an interior mating flange defining a second annular mating face, said interior mating flange defining an outer perimeter and an inner perimeter; an inner insertion flange extending laterally from the inner perimeter of the interior mating flange, having sufficient length to allow a fixed, direct attachment to an inner duct of a double wall circular duct; and an interior hem that is substantially concentric to the inner insertion flange, said interior hem extending from the outer perimeter of the interior mating flange generally in the same direction as the inner insertion flange to overlap the inside surface of the outer insertion flange wherein the interior hem is connected to the inside surface of the outer insertion flange by any common means of fastening such that the interior mating flange and the exterior mating flange are aligned to form substantially one plane, the interior hem being of such length to permit the outer insertion flange to be fixedly attached to the interior of an outer duct wall and having sufficient length to allow connection with the outer insertion flange; the inner insertion flange, the interior mating flange and the interior hem collectively formed as a singular structure comprising the second ring.