Forming freshly extruded tubing to a twin channel hose - to obtain a complex hose using a simple annular die

摘要

To make a hollow tube with a longitudinal surface pocket to accommodate a smaller tube or form an ancillary passage within a circular profile, part of the wall of a freshly extruded tube is progressively deformed radially inwards while the curvature of the opposite side of the tube is supported by a coaxial former. The recess is then closed around an ancillary cylindrical mandrel to form a tubular channel which may be sealed by welding the channel rims together. For mfr. of packs or feed tubes for holding or injecting two materials simultaneously without mutual contact, using a single extruded profile, hence the minimum of extrusion equipment.