GB1242726A - Method and apparatus for vacuum skin packaging - Google Patents

Abstract

1,242,726. Vacuum skin packaging. W. E. YOUNG. 2 Oct., 1968 [2 Oct., 1967], No. 46718/68. Heading B8C. A method of packing includes the steps of placing a product 108 to be packaged upon a lower packaging member 104 having an upper surface adapted for heat sealing to an upper thermoplastic film, heating the film to a softened condition for draping, moving the product 108 and the film relative to each other to cause the film to drape over the product, bringing each side of the film to a condition of substantially equal reduced pressure either before or after the film is draped over the product and relaxing the reduced pressure above the film so that the film is urged by the increased pressure against the product and the packaging member to form a heat sealed skin packaged product. In the construction shown the apparatus for carrying out the above method comprises an upper housing member 122 and a lower housing member 126 which co-operate to form an hermetically sealed chamber, means for moving the housing members relative to each other, to close and open the chamber and fluid conducting means 134, 144 for evacuating and venting to atmosphere the chamber. Means are provided for feeding a strip 106 of thermoplastic film between the housing members 122, 126 to form the upper thermoplastic film and means 120 for heating the film to warm the film to a draping condition. Means for feeding the lower packaging member 104 having the product 108 thereon to between the housing members 122, 126 are provided such that on the bringing together of the housing members or on moving the product into the film (Figs. 1 to 9, not shown) the film drapes about the product. Both sides of the film within the chamber are brought to substantially the same reduced pressure and then the upper part of the chamber is vented to atmosphere closely followed by the venting of the lower part. The strip 106-is fed to the chamber between continuous roller chains 114 and cooperating endless belts 115. A supplementary heating means may be provided within the chamber. The sealed package is transferred to a severing end discharge station 128 where by means of a hot wire trimmer 166 the package is cut from the film 106 and passes on a platform 170 from the line of movement of the package carrier 102. In a further embodiment (Figs. 1 and 15, not shown) the lower package member is formed from a continuous film which passes through the apparatus. The chamber may be formed of two or three parts (Figs. 1, 2, not shown), heaters being pivotally mounted in the upper housing member (Figs. 1 to 5, not shown) or mounted in the lower housing member (Figs. 6 to 8, not shown).