Abstract: A method and apparatus for forming a pressure vessel liner are disclosed. One method includes forming an extruded tube by extruding a parison through a die and a mandrel and forming main body sections and return line sections in the extruded tube according to a first pattern. A cross-sectional area of the return line sections is smaller than a cross-sectional area of the main body sections. The method further includes changing the pattern according to which the main body sections and the return line sections are formed from the first pattern to a second pattern without stopping the forming of the extruded tube and forming the main body sections and the return line sections in the extruded tube according to the second pattern.

Abstract: A method and system for recycling permeated gas is disclosed. A container encapsulating a pressure vessel defines a containment volume. Gas permeating through the pressure vessel is captured in the containment volume. When a sensor detects a threshold level of permeated gas captured within the containment volume, a control module sends a command to open a purge valve. The open purge valve allows permeated gas captured within the containment volume to be supplied to an engine, a repressurization unit, or a secondary container.