Method for strengthening duct cores

摘要

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.