A coupling member for connecting a part, provided for receiving or dispensing
fuel
and made primarily of HDPE (high-density polyethylene), to a fluid line has first,
second, and third components made of meltable material. The third component forms
a heat fusion joint with the part for receiving or dispensing fuel and has an undesirably
high permeability and swelling capacity relative to fuel. The third component is
connected to the first component by material bonding and positive-locking action.
The second component has greater fuel blocking capacity and higher strength than
the third component. The second component is embedded in the third component. A
volume ratio of second and third components is selected such that combined properties
of the second and third components concerning permeability, strength, and volume
changes by swelling are approximated to these same properties of the second component.
The first and third components are heat-fusible to one another.
