Abstract: Disclosed is a method of sizing nonderivatized extruded cellulosic tubes by the use of a mandrel structure that includes a hollow sizing portion having openings which gather gas bubbles that may evolve at the interface between the extruded tube and the sizing portion and allows the gas to pass into the hollow interior of the mandrel. The mandrel contains a sizing portion larger than the extruded tube, which allows for improved sizing of nonderivatized extruded tubes that are used as casings.

Abstract: A method and apparatus is disclosed for lacing an extruded tube of a non derivatized cellulose through an S-wrap to collapse the tube to a flat width. The lacing to form the S-wrap is accomplished without slowing the extrusion speed. At the start of the extrusion operation, the extrusion path leads between a pair of horizontally lacing members. After the leading edge of the extruded tube has passed downwardly through the space between the lacing members, the members are rotated as a unit to bring them into contact with opposite sides of the extruded tube. This collapses the and creates the S-wrap.