Abstract: Container bags for intravenous solution of one-piece, blow-molded construction typically have a fill port or tube and at least an administration port in one end of the container bag. A method, an apparatus and an article of manufacture are provided where a fill port or tube on a polyolefin or other plastic container bag is sealed into a dome shape where the solid wall, dome-shaped material closing the port or tube effects the seal. The method provides for sealing the open end of a thermoplastic tube or port by using respectively hot and cold dies. Resistance of the tube or port to forming a seal at adjoining interfaces is overcome by rotating at least one of the dies. Disruption and mixing of the plastic at the interface or closure line is accomplished, forming a substantially homogenous mass which seals the port opening.

Abstract: An apparatus and a method are provided where two relatively rotatable plastic tubes in telescoping relation are welded together at their telescoping, contacting interface. In practicing the invention, soft and flexible thermoplastic tubes are fitted in telescoping relationship, one inside the lumen of the other. Gripping jaws compress and shape the outer tube uniformly which stiffens the inner and outer tubes and defines a contacting interface. Axially spaced from the interface, the inner tube is chucked with shaping jaws to impart a polygonal, cross-sectional shape to the inner tube. Frictional heat generated by rotating one tube relative to the other tube softens the interface allowing the tubes to weld together when rotation is stopped.