Plastic lined metal fuel tanks - with the lining shape controlled by vacuum, forming over porous foam inserts

摘要

Vessels made by vacuum forming thermoplastic sheet to line a prefabricated metal base where shape of the thermoplastic lining may be diverted from that of the metal base, esp. in the region of the vacuum outlet, by the use of porous foam inserts which pref. are elastomeric. Esp. for making mating halves of a hollow vessel or container, esp. fuel tanks. The foam replaces a perforated vacuum pipe or manifold to provide a more progressive application of vacuum, to ensure evacuation of remote zones and to permit greater variation in the surface profile of the lining, e.g. to provide antisurging baffles or reserve chambers. The foam may be fibre reinforced, pref. with non-inflammable fibres.