SEMI-RIGID FLEXIBLE DUCT

摘要

A semi-rigid, flexible duct (100) including a pair of coaxial sleeves, namely an inner sleeve (224) and an outer sleeve (234) disposed parallel to and about the inner sleeve and a resilient wound element (250) disposed between the sleeves. Each of the inner and the outer sleeve includes a first layer (222,232) having metallic properties and at least on of them further includes a second, plastic layer bonded to the first layer. The wound element imparts corrugations to the two sleeves, such that the duct is extendable between a compacted configuration suitable for storage and for shipping and an extended configuration suitable for installation in a gas transport arrangement. All of the layers of both the inner sleeve and the outer sleeve are of a thickness predetermined to together render the duct substantially rigid when in an extended configuration and predetermined to together enable the duct to maintain its substantial rigidity upon extension from a compacted configuration.