Patent GB-1251672-A (GB)
IPC: B65B51/10
Filed: 1968-02-29
Abstract: 1,251,672. Packaging under superatmospheric pressure. IMPERIAL CHEMICAL INDUSTRIES Ltd. 3 Feb., 1969 [29 Feb., 1968; 14 June, 1968], Nos. 9849/68 and 28360/68. Heading B8C. In the packaging of liquid or particulate materials in a flexible cylindrical plastics container 16, superatmospheric pressure is introduced therein from an orifice 5 in a smooth surface 2 over which a container aperture 17 is located in gas-tight contact, whereafter the aperture 17 is displaced in sealing contact over the smooth surface 2 into contact with and sealed by a flexible sealing strip 10. The package may comprise a solid article introduced prior to the gas, or a liquid or particulate material introduced through the same orifice as the gas or through another orifice prior to or after displacement of the container. In the packaging of beer, pressurized carbon dioxide is introduced from a reservoir containing the beer and providing a gravitational head, and the beer is then introduced through a retractable probe 4. The surface 2 is provided in a brass block 1, and the strip 10, which may comprise a carrier strip for separate heat sealable patches, is fed over an impulse heating element 11, of stainless steel strip, covered by polytetrafluoraethylene impregnated glass cloth, supported on a hardbonded asbestos block 8. The container 16 is supported against the block 1 and displaced by a transparent polymethyl methacrylate plate 15 slidable parallel to the surface 2, and the blocks 2 and 8 comprise an assembly slidably mounted for movement towards the plate 15 and away therefrom against a stop to accommodate the varying container size during inflation thereof by the gas, e.g. at 30 p.s.i. The apparatus is preferably arranged with the surface 2 downwardly inclined at 20 degrees to the horizontal, whereby a gas space remains above the contents around the aperture 17 in the upper part of the container to facilitate the sealing, either the blocks 2, 8 being gravity loaded or the plate 15 spring-urged, towards the container. The surfaces 2, of the block 8, and of the plate 15 may be flat, cylindrical, or otherwise curved with a radius greater than the container 16 which may be displaced parallel to its axis, throughout, or in this direction to the gas orifice and then in a different direction to a material-filling orifice. After sealing, the container may be rotated for the attachment of a tape around the aperture 17. The liquid or particulate solid may be fed by a pressurized metering device. The heal-seal may alternatively be effected on the moving container, over successive heated and cooled zones. The filled containers are preferably provided with a wrapped sleeve of paper or foil which is secured by a hot melt adhesive, and which sleeve is applied to a cold container whereby subsequent expansion thereof results in a firmer support, e.g. for labelling and decoration. The sleeve may project at one end to form a stand. The process may be carried out on containers fed successively as a continuous strip of containers formed from tubular plastics film in which filling apertures and then transverse heat seals are formed. A ligature is applied to each side of each heat seal in the strip, and if located partly on the seal is preferably an encircling tight metal band, or if below the seal on the container, comprises a plastics coated wire ligature or metal clip. The containers may be separated by dividing through a seal, or between spaced seals. The containers may be produced from a strip of folded film longitudinally sealed by a lapped seal, and this method may be adapted to produce bunched neck containers of the type described in Application No. 35333/67, the regions of greater cross-sectional area of the necks being provided by forming tucks prior to sealing to include more than two film layers therein, or by feeding plastics strips into the heat-sealing region, or by forming crimped seals. The containers preferably comprise biaxially oriented polyethylene terephthalate film, preferably externally coated with heatsealable vinylidene chloride copolymer. The container aperture is preferably sealed by hotmelt adhesive, on a plastics carrier strip of the same type as the container, such as those based on co-polymers based on two or more of the acids sebacic, terephthalic, and isophthalic acid condensed with ethylene glycol. Ethylene/ vinyl acetate copolymer hot-melt adhesives, or a pressure-sensitive adhesive coating, may be employed.