Vertical form, fill, seal machine and methods

Abstract

In a vertical form, fill, seal machine that produces liquid-filled stand-up pouches, a flat vertical fill tube is surrounded by an envelope of thermoplastic film that is closed along one longitudinal edge and open along the opposite longitudinal edge. A main drive assembly includes drive members that press opposite sides of the envelope against the flat fill tube. An auxiliary film drive assembly is responsive to film tension. Stand-up base cups are formed seriatim along the closed longitudinal edge of the envelope. Fitments are inserted seriatim into the open longitudinal edge, in correspondence with respective cups, and are sealed to the thermoplastic film, first by a spot-sealer and then by a top sealer. End seal/cut-off assemblies provide a seal transversely of the envelope that is bisected by a knife to release a leading pouch that has been formed, filled, and sealed. Prior to end sealing and cut-off, a predetermined quantity of liquid is dispensed from the bottom of the fill tube into a pouch next to the leading (just-filled) pouch. A deflater assembly evacuates and stabilizes a region of the envelope at which each end seal is formed.

The invention claimed is:  
     
         1 . A vertical form, fill, seal machine for producing filled stand-up pouches, comprising:  
 a vertical fill tube constructed to receive product from a product supply and to dispense a quantity of product from a lower portion of the fill tube;     film supply apparatus constructed to provide a vertical film envelope surrounding the fill tube;     a drive assembly including a pair of drive members disposed at opposite sides of the envelope and constructed to press respective sides of the envelope against the fill tube;     a base-former assembly constructed to transform a portion of the envelope adjacent to a first longitudinal edge thereof into a series of stand-up bases for respective pouches;     a top sealer assembly constructed to provide top seals along portions of a second longitudinal edge of the envelope opposite to corresponding bases;     an end sealer assembly constructed to provide seals at opposite side edges of each pouch being formed, extending between each top seal and a corresponding base, and to entrap a quantity of product dispensed from the fill tube into each pouch being formed; and     a cut-off assembly constructed to separate each product-containing pouch from the envelope.    
     
     
         2 . A machine according to    claim 1   , wherein the film supply apparatus is constructed to supply a web of thermoplastic film to an envelope-former at an upper portion of the machine, and the envelope-former is constructed to fold the web longitudinally so as to provide a two-layer vertical film envelope closed along the first longitudinal edge and open along the second longitudinal edge, and wherein the fill tube is flat and extends transversely within the envelope throughout a major portion of the width of the envelope.  
     
     
         3 . A machine according to    claim 1   , wherein the base-former assembly is constructed to form cup-shaped bases from gussets having a substantially W-shaped cross-section, each gusset including two pairs of film layers, and wherein the base-former assembly includes a cup sealer assembly disposed and constructed to heat seal the layers of each pair to one another separately from the layers of the other pair, to form a cup.  
     
     
         4 . A machine according to    claim 3   , wherein the base-former assembly includes a cup seal chiller assembly disposed and constructed to chill the sealed layers of each cup.  
     
     
         5 . A machine according to    claim 4   , wherein the base-former assembly includes a nip sealer assembly disposed and constructed to seal four layers of the envelope to each other along opposite ends of each cup.  
     
     
         6 . A machine according to    claim 1   , further comprising a fitment supply assembly disposed and constructed to insert fitments seriatim into the open longitudinal edge of the envelope at positions aligned with corresponding bases.  
     
     
         7 . A machine according to    claim 6   , further comprising a spot sealer assembly disposed and constructed to thermally spot seal each fitment to the envelope.  
     
     
         8 . A machine according to    claim 7   , wherein the top sealer assembly is constructed to heat seal to one another the two layers of the envelope around each spot sealed fitment along a length of the open longitudinal edge of the envelope corresponding to a top edge of a pouch being formed.  
     
     
         9 . A machine according to    claim 1   , wherein the end sealer assembly is constructed to form, simultaneously, a seal along a side edge of one pouch being formed and an abutting side edge of a next pouch being formed, and wherein the cut-off assembly is constructed to bisect the seal between the abutting side edges.  
     
     
         10 . Apparatus according to    claim 1   , further comprising a deflater assembly disposed and constructed to engage the envelope from opposite sides thereof to deflate and stabilize a portion of the envelope at which each end seal is to be formed.  
     
     
         11 . In a vertical form, fill, seal machine, a vertical fill tube extending longitudinally within a film envelope and transversely throughout a major portion of the width of the envelope, and a film drive assembly comprising a pair of drive members disposed and constructed to press opposite sides of the envelope against the fill tube and to advance the envelope along the fill tube.  
     
     
         12 . In a vertical form, fill, seal machine in which a vertical envelope of thermoplastic film surrounds and is advanced along a vertical fill tube, the envelope being open along a longitudinal edge:  
 a fitment supply assembly disposed and constructed to insert fitments seriatim between opposite sides of the envelope at the open longitudinal edge, at portions of the envelope spaced longitudinally;     a spot sealer assembly disposed and constructed to thermally spot seal each inserted fitment to the envelope;     and a further sealer assembly disposed and constructed to heat seal the sides of the envelope to one another along a predetermined length of the envelope that extends over and beyond each spot sealed fitment.    
     
     
         13 . In a vertical form, fill, seal machine:  
 a vertical fill tube;     envelope-forming apparatus constructed to form an envelope of film surrounding the fill tube longitudinally; and     a base-former assembly constructed to form the film into a series of stand-up bases arranged along a longitudinal edge of the envelope, whereby each of a series of pouches to be formed and filled by the machine is provided with a base at the bottom of the pouch so that the pouch may stand up, self-supported.    
     
     
         14 . A machine according to    claim 13   , wherein the base-former assembly is constructed to form each base from a gusset with two pairs of film layers, and to seal the layers of each pair to one another separately from the layers of the other pair.  
     
     
         15 . A machine according to    claim 14   , wherein the base-former assembly is constructed to form each gusset with a configuration that is W-shaped in cross-section and that comprises four layers of film.  
     
     
         16 . A machine according to    claim 15   , wherein the base-former assembly comprises a sealer assembly constructed to seal two layers of film to one another at each of opposite sides of each base and a further sealer assembly constructed to seal all four layers of film to each other along opposite ends of each base.  
     
     
         17 . In a method of producing pouches:  
 providing a vertical film envelope surrounding a vertical fill tube, and driving the envelope along the fill tube by engaging drive members with opposite sides of the envelope backed up by the fill tube.    
     
     
         18 . A method according to    claim 17   , further comprising forming a series of stand-up bases along a longitudinal edge of the envelope.  
     
     
         19 . A method according to    claim 18   , wherein the envelope is sealed around each base to provide a bottom seal and is sealed along an opposite longitudinal edge to provide a top seal for each pouch being formed, and further comprising:  
 providing a side edge seal for each pouch being formed, whereby each pouch being formed constitutes a receptacle for receiving product from the fill tube;     dispensing product from the fill tube into the receptacle;     forming a further side edge seal for each pouch to enclose the product; and     separating each product-containing pouch from the envelope.    
     
     
         20 . A method according to    claim 18   , further comprising attaching fitments to the envelope corresponding to the bases, respectively.  
     
     
         21 . In a method of producing pouches with fitments:  
 providing an envelope having layers forming an open longitudinal edge;     moving the envelope longitudinally;     inserting fitments seriatim into the open edge of the envelope at positions spaced along the length of the envelope; and     attaching the fitments to the envelope.    
     
     
         22 . A method according to    claim 21   , wherein each fitment is spot sealed to the envelope and is then further sealed to the envelope by a seal that extends along the length of the envelope around the spot sealed fitment.  
     
     
         23 . In a method of producing stand-up pouches on a vertical form, fill, seal machine:  
 forming a gusset having a configuration that includes two pairs of film layers;     sealing the layers of each pair to one another separately from the layers of the other pair; and     sealing all of the layers of the two pairs to each other along opposite ends of the gusset.    
     
     
         24 . In a method of producing pouches:  
 supplying a length of film;     folding the film longitudinally to form an envelope surrounding a vertical fill tube such that the envelope has a closed longitudinal edge and an open longitudinal edge; and     moving the envelope longitudinally along the fill tube.    
     
     
         25 . A method according to    claim 24   , wherein fitments are inserted into the open longitudinal edge at positions spaced longitudinally of the envelope and are attached to the envelope.  
     
     
         26 . A method according to    claim 24   , wherein the closed longitudinal edge is formed into a series of stand-up bases.  
     
     
         27 . A method according to    claim 26   , wherein the forming of each stand-up base includes forming a gusset progressively as the envelope is moved along the fill tube and sealing portions of the gusset.  
     
     
         28 . A method according to    claim 27   , wherein the sealed portions of the gusset are then chilled.  
     
     
         29 . A method according to    claim 28   , wherein other portions of the gusset are then sealed.  
     
     
         30 . A method according to    claim 24   , wherein the film supplied is maintained under substantially constant tension.