Vacuum Flow Wrap Packaging System and Method of Packaging

Abstract

A method and packaging system for forming a sealed vacuum package having minimal residual air remaining. At least one vacuum lance is provided in the interior of a partially-formed package to withdraw the air, the package being closed on three sides and having a fourth side open for insertion of the vacuum lance. An air restriction can be provided along the fourth side to form a closed edge that prevents ingress of air into the package interior after the evacuation of air. In one aspect, the air restriction may comprise a pair of pinch rollers that compress the package at the fourth side edge to form a pinch seal that provides a relatively airtight air chamber inside of the package prior to and during sealing of the package. In another aspect, the air restriction may comprise a partial seal formed around the lances to prevent or minimize air from reentering the package. In yet another aspect, the air restriction may comprise a compressed air seal formed by an air compression device that keeps the ends of the film pressed together.

1 - 18 . (canceled) 
     
     
         19 . A method of withdrawing air before sealing a package containing a product, the method comprising the steps of:
 inserting a vacuum lance into an interior section of a partially-sealed package having three sides closed and the vacuum lance is inserted adjacent a product contained in the interior section through a fourth, unsealed side;   forming an air restriction barrier at the fourth side of the partially-sealed package;   drawing a vacuum through the vacuum lance to evacuate the air from the interior section;   withdrawing the vacuum lance from the interior section; and   sealing the fourth side of the partially-sealed package to form a sealed package.   
     
     
         20 . The method of  claim 19 , wherein forming the air restriction barrier includes forming a partial seal, a pinch seal or an air compression seal. 
     
     
         21 . The method of  claim 19 , wherein the step of inserting the vacuum lance further includes inserting a double tube vacuum lance with an outer tube surrounding an inner tube, the outer tube having multiple holes at least partially along its length. 
     
     
         22 . The method of  claim 21 , wherein the step of drawing a vacuum further includes creating a vacuum in the outer tube and drawing down a top and a bottom film portion of the partially-sealed package onto an outer surface of the outer tube and by adding a vacuum through the inner tube that withdraws air from within the interior section of the partially-sealed package. 
     
     
         23 . The method of  claim 19 , wherein drawing a vacuum through the vacuum lance further includes drawing the vacuum through one or more small holes of the vacuum lance near the fourth, unsealed side to pull a top and bottom film portion of the partially-sealed package down onto the surface of the vacuum lance. 
     
     
         24 . The method of  claim 19 , wherein the step of forming the air restriction barrier further includes forming the barrier in a direction transverse to a machine direction. 
     
     
         25 . The method of  claim 19 , wherein the step of forming the air restriction barrier further includes the step of forming a pinch seal using a pair of pinch rollers, the pinch seal closing off the fourth, unsealed side to create an essentially airtight interior section. 
     
     
         26 . The method of  claim 25 , wherein the step of forming a pinch seal further includes pinching the film at both a top and a bottom film portion with the pair of pinch rollers. 
     
     
         27 . The method of  claim 26 , wherein forming the pinch seal further includes rolling the pair of pinch rollers over the top and the bottom film portions, the rollers comprising a top and a bottom roller wherein at least one of the rollers is a soft, compliant roller. 
     
     
         28 . A method of forming a plurality of sealed packages in sequence including the steps of:
 depositing a food product or an array of spaced food products onto a bottom film portion;   overlaying the bottom film portion and the food product or food products with a top film portion; and   withdrawing air before sealing the package according to the method of  claim 19 .   
     
     
         29 . The method of  claim 28 , further comprising the step of forming the interior section of the partially-sealed package by sealing a leading edge and side edges to form the partially-sealed package containing the food product or food products. 
     
     
         30 . The method of  claim 29 , further comprising the step of advancing the partially-sealed package in a machine direction together with the food product or food products while the vacuum lance remains stationary. 
     
     
         31 . The method of  claim 30 , wherein the step of withdrawing the vacuum lance further includes advancing the partially-sealed package in the machine direction beyond an end of the stationary vacuum lance. 
     
     
         32 . The method of  claim 19 , further comprising inserting a second vacuum lance. 
     
     
         33 . The method of  claim 32 , wherein the step of inserting the vacuum lances further comprises inserting each vacuum lance along opposite closed and parallel sides spaced from one another by the product contained in the package. 
     
     
         34 . The method of  claim 19 , wherein the step of drawing a vacuum further includes evacuating air from the interior section such that no more than about 20 cc of air remains in the package. 
     
     
         35 . A method of forming a vacuum package for a packaged food product, the method comprising the steps of:
 advancing a bottom web of film in a machine direction;   arranging a food product on the bottom web of film;   overlaying the food product and bottom web of film with a top web of film;   sealing a pair of parallel longitudinal side edges between the top and bottom web portions to form a continuous longitudinal side seal;   sealing a leading edge portion between the top and bottom web portions downstream of the food product to form a partially-sealed package with an interior section that contains the food product;   inserting a vacuum lance between the bottom web of film and top web of film, adjacent the food product and into the interior section;   forming a temporary air restriction at a fourth, unsealed trailing edge;   evacuating air from the interior section of the package by drawing a vacuum through the vacuum lance as the partially-sealed package continues to advance in the machine direction; and   sealing the fourth, unsealed trailing edge after the package advances past an end of the vacuum lance to form a sealed vacuum package.   
     
     
         36 . The method of  claim 35 , wherein the step of evacuating air from the interior section further includes evacuating air to a level where about 20 cc or less of air remains. 
     
     
         37 . The method of  claim 35 , wherein the step of arranging the food product further includes arranging multiple food items in a shingle arrangement. 
     
     
         38 . The method of  claim 35 , wherein the step of forming the temperature air restriction further comprises forming a pinch seal using a pair of pinch rollers to press against the top and bottom web of film at the fourth side to close the fourth side.