Today in 2000, US Patent WO 2000078665 A1 was issued, an invention of William Field Warwick, assigned to Carlton and United Breweries, for his “Beer Container.” Here’s the Abstract:

A beer container comprises an inner hollow shell (11) of blow moulded PET to hold beer, an outer hollow shell (12) of moulded high density polyethylene enclosing and supporting the inner shell and a spear structure (13) including a dispenser tube (14) extending from a bottom interior region of the inner shell (11) through to a dispensing outlet (16) at the top of the outer shell (12). Spear structure (13) incorporates valves (25, 26) for supply of pressurising gas into the interior of inner shell (11) and for dispensing beer through the dispensing outlet (16), both valves being formed of PET. When the container has been emptied of beer, the outer shell (12) can readily be separated from the inner shell (11) and spear structure (13) to allow separate recycling of the high density polyethylene material and the PET material.