Plastic bag for the vacuum preservation of food

Abstract

A bag of plastic material for vacuum preservation of food comprises two rectangular walls joined together along three sides. The width of one of the walls is larger than the width of the other wall by a predetermined quantity, preferably about 5%.

What is claimed is:  
     
         1 . A bag of plastic material for the vacuum preservation of foodstuffs, comprising two rectangular walls joined together along three sides, wherein the width of one of the walls is larger than the width of the other wall by a predetermined quantity.  
     
     
         2 . The bag of  claim 1 , wherein the quantity by which the width of one wall exceeds the width of the other wall is in the range 2% to 10%.  
     
     
         3 . The bag of  claim 2 , wherein said excess quantity is 5% of the width of said other wall.  
     
     
         4 . A process for mass-producing bags according  claim 1 , wherein two superposed ribbons of plastic sheet are continuously fed along a path and transverse welding bars are applied at intervals to the ribbons to obtain welds joining the ribbons together to form longitudinal sides of the bag, characterized in that one of the ribbons is fed at a higher speed than the other ribbon.  
     
     
         5 . A process for mass-producing bags according  claim 1 , wherein two superposed ribbons of plastic sheets are continuously fed along a path and longitudinal welding bars are applied to the opposite edges of the ribbons to obtain welds joining the ribbons together to form longitudinal sides of the bag, wherein a humped plate is inserted between the ribbons.