Process for end sealing a bag and apparatus therefor
AssigneeWhitehall Machinery Limited
InventorGeoffrey Terence Webber
Life of this patent
Estimating the term…
Abstract
Superimposed heat-sealable layers are heat-sealed by applying external suction to draw the layers apart, inserting a nozzle between the parted layers, directing hot gas from the nozzle onto the inside surfaces of the layers, removing the nozzle and pressing the heated surfaces together. Preferably the layers are carried by a conveyor, such as between a pair of endless chains, along a path on which the suction means, nozzle means and pressing means are successively arranged.
Claims7
Apparatus for continuous heat-sealing the mouths of sacks, comprising means for transporting the sacks along a path with opposite sides of each sack at the mouth drawn together in superimposed relationship, suction means located on either side of the path for drawing the sides of the sack apart at the mouth, nozzle means located in the region of said suction means and arranged for movement into and out of the open mouth of each passing sack to direct heated gas therefrom onto the inner surfaces of the sack in the region to be heat-sealed, and means located on the path beyond the nozzle means for pressing the thus heated sides of the bag together at the mouth to effect the heat-seal between the two sides, the nozzle means having nozzle openings forwardly and rearwardly in the direction of travel of the sack such that, in operation, heated gas from the forward nozzle openings is directed into the leading fold of the sack as the nozzle enters the mouth, and heated gas from the rearward nozzle openings is directed into the trailing fold of the sack as the nozzle is removed from the mouth of the sack.
Apparatus for continuous heat-sealing the mouths of sacks, comprising means for transporting the sacks along a path with opposite sides of each sack at the mouth drawn together in superimposed relationship to each other, suction means located at either side of the path adapted to draw the sides of the sack apart at the mouth, nozzle means located in the region of said suction means and arranged for relative movement into and out of the open mouth of each passing sack to direct heated gas therefrom onto the inner surfaces of the sack in the region to be heat-sealed, lateral support means arranged on either side of the path to locate the sides of the sack mouth in closely spaced relationship to the sides of the nozzle when the nozzle is positioned in the sack mouth, and means located on the path beyond the nozzle means for pressing the sides of the bag thus heated together at the mouth to effect the heat-seal between the two sides.
A continuous method for heat sealing the mouths of sacks comprising the steps of:
- transporting each sack along a path with opposite sides at the mouth of each sack drawn together in superimposed relationship, the mouth having a leading fold, sides and a trailing fold;
- drawing the sides of the sack apart at the mouth by suction means located on either side of the path;
- moving a nozzle into and then out of the open mouth of the sack in passing, and directing heated gas from the nozzle into the leading fold of the sack mouth as the nozzle enters, onto the sides of the sack mouth while the nozzle remains stationary therein, and then into the trailing fold of the sack mouth as the nozzle is removed therefrom;
- and
- pressing the thus heated surfaces together to effect the heat-seal.
Dependencies are inferred from the claim text.