Abstract: Strengthening the core of an insulated flexible duct formed of a helical wire wrapped with a flexible material with reinforcing tape. Strengthening tape is applied to the surface of the duct along its entire length. The apparatus for applying the strengthening tape is a tray having adjustable wiping arms. The wiping arms stretch the duct out as it is pulled through the tray. A roll of tape is mounted adjacent to the wiper arms and is automatically applied as the duct is pulled along the tray through the wiper arms. At least two wiper arms and continuous strips of tape along the longitudinal surface of the duct core are preferred.

Abstract: A method and apparatus for strengthening the core of an insulated flexible duct formed of a helical wire wrapped with a flexible material. Strengthening tape is applied to the surface of the duct along its entire length. The apparatus for applying the strengthening tape is a tray having adjustable wiping arms. The wiping arms stretch the duct out as it is pulled through the tray, testing bonds securing the material around a reinforcing coil of wire. A roll of tape is mounted adjacent to the wiper arms and is automatically applied as the duct is pulled along the tray through the wiper arms. At least two wiper arms and continuous strips of tape along the longitudinal surface of the duct core are preferred.

Abstract: A universal air diffuser comprised of a fiberglass plenum having an open side and means for attaching a duct connector on a closed side opposite the open side. The closed side of the fiberglass plenum is covered with a close-fitting non-porous material which reinforces the fiberglass to allow cutting holes for attachment of air ducts. A plurality of shallow grooves on the exterior of the closed surface provide cutting lines for hole patterns to cut holes for various standard size ducts. The reinforcing material is a fiberglass-reinforced foil which maintains the integrity of the hole cut in the surface and provides a non-porous surface for adhering to duct tape.