Abstract: A carton containing a compressed flexible duct for selected removal of portions of the duct, the carton having a first pair of end flaps and a second pair of end flaps for closing the top end of the carton. The flaps of the first pair each have a length more than one-half the length of the top end to fold segmentally into diagonal extensions into the carton where the distal edges of the first pair can abut each other. The second pair of flaps each has a pair of diagonal creases from the end edges to the distal edge to allow folding of the flap ends to form stops for the first pair of flaps to retain the compressed duct in the carton.

Abstract: A flexible duct and carton for retaining and enabling controlled dispensing of the flexible duct positioned therein, the duct preferably being in a U-shaped orientation abutting end walls of the carton. The carton has a width about the diameter of the duct, and a breadth at least about twice the diameter of the duct. A breakout panel in a side wall adjacent one of the end walls forms a lateral outlet opening which has a width and a height greater than the duct diameter, whereby an end of the duct can be turned 90.degree. and pulled out in controlled lengths.

Abstract: A semi-rigid collapsible air duct having helically biasing reinforcement element 24, enveloped between an inner skin and an outer skin with the reinforcement element in a uniform helical spacing enveloped by ultrasonic welds. The process for manufacturing the air duct includes feeding the inner duct wall skin onto a mandrel, feeding the helically biased reinforcement element onto the mandrel having a groove with a tighter helical shape over the inner duct wall skin, feeding the outer duct wall skin onto the mandrel over the reinforcement element, then passing that composite under an ultrasonic welder which welds the inner duct wall skin to the outer duct wall skin, enveloping one or more reinforcement elements in such a way as to leave the one or more reinforcement elements free to move within their respective envelopments to develope the maximum thrust to place the reinforcing elements in tension to prevent droop of the walls of the duct.