Patent ID: 6185913
Filing Date: 2001-02-13
Classification: B65B

Abstract:
An apparatus for packaging products with a stretchable gas-tight film, comprising:a wrapping machine which forms a package for the product which is sealed with respect to an ambient atmosphere, said wrapping machine includinga) a reel of stretchable gas-tight film,b) an unwinding means for cyclically unwinding a portion of the film from the reel,c) a wrapping means for wrapping the product with the portion of film and for forming overlapping flaps of the film, andd) a sealing means for sealing the overlapping flaps of the film to form the sealed package;a sealable main chamber in which said wrapping machine is completely contained;an atmosphere means for creating and maintaining said chamber with a modified atmosphere having characteristics suitable for the conservation of the products packaged in said wrapping machine and modified with respect to the ambient atmosphere;a sealable entry airlock chamber connecting said main chamber with the ambient atmosphere, said entry airlock chamber includinga) an entry passage means for passing the products to be packaged into said entry airlock chamber from the ambient atmosphere,b) entry sealing doors by which an interior of said entry airlock chamber is connected to the ambient atmosphere and to the main chamber;a sealable exit airlock chamber connecting said main chamber with the ambient atmosphere, said exit airlock chamber includinga) an exit passage means for passing the packaged products into the ambient atmosphere from said exit airlock chamber,b) exit sealing doors by which an interior of said exit airlock chamber is connected to the ambient atmosphere and to the main chamber;a control means for controlling said sealing doors such thata) in a first action of said control means, said entry airlock chamber is closed to the main chamber and opened to the ambient atmosphere,b) in a second action of said control means, said entry airlock chamber is closed to the ambient atmosphere and opened to the main chamber,c) in a third action of said control means, said exit airlock chamber is closed to the ambient atmosphere and opened to the main chamber, andd) in a fourth action of said control means, said exit airlock chamber is closed to the main chamber and opened to the ambient atmosphere;an introducing means for introducing a product to be packaged into said entry airlock chamber after said first action of said control means;an entry transferring means for transferring the product from the entry airlock chamber to the main chamber after said second action of said control means whereby said wrapping machine in said main chamber then forms the package with a portion of the modified atmosphere trapped in the wrapped product;an exit transferring means for transferring the wrapped product into said exit airlock chamber from said main chamber after said third action of said control means; anda discharging means for discharging the wrapped product from said exit airlock chamber after said fourth action of said control means;wherein said entry airlock chamber further comprisesa) a transfer conveyor mounted on pulleys with horizontal axes such that said transfer conveyor is divided into a lower straight run and an upper straight run,b) a series of plates fixed to said transfer conveyor at equal intervals to divide the interior of said entry airlock chamber into respective chamber portions,c) respective side pieces provided on respective lateral sides of said transfer conveyor such that respective lateral edges of said plates interact respectively therewith to form a seal;d) an underlying horizontal belt conveyor on which the products are supported and which isi) positioned underneath the lower straight run of said transfer conveyor,ii) connected mechanically to said transfer conveyor, andiii) spaced from the lower straight run of said transfer conveyor so that horizontal edges of said plates interact and form a seal therewith,e) a fixed casing integral with said side pieces which is located above said upper straight run of said transfer conveyor and which is spaced from the upper straight run of said transfer conveyor so that the horizontal edges of said plates interact and form a seal therewith, andf) a second atmosphere means for creating the modified atmosphere in each said chamber portion as each said chamber portion is located along said horizontal belt conveyor and is isolated from the ambient atmosphere; andsuch that in a cyclic manner the chamber portions change positions when advanced through an interval equal to the distance between said plates so as to constantly keep said main chamber isolated from the ambient atmosphere and so that,a) while a first chamber portion is connected to the ambient atmosphere to receive the product to be packaged,b) at least a second and subsequent chamber portion containing the product to be packaged is isolated from the ambient atmosphere and connected to said second atmosphere means,c) while a third and subsequent chamber portion containing the modified atmosphere and product is in communication with said main chamber for the introduction into said main chamber of the product to be packaged, andd) at least a fourth chamber portion is provided which is sealed from the ambient atmosphere and from said main chamber and which is located after the third chamber portion and between the third chamber portion and the first chamber portion.