Shrink tunnel and methods relating thereto
AssigneeE. I. Du Pont de Nemours and Company
InventorsJohn Farrell Cox, Frederick Henry Fiesser, Robert Vincent Jeral, Donald Earl Erlston, Jr., Richard Alan Hansen
Life of this patent
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Abstract
An apparatus for shrinking a heat-shrinkable film around a product. The apparatus has a first heating stage which heats a portion of the underside of the package to properly position the shrink film and a second heating stage which further shrinks the film. Side heating jets can optionally be used to heat the sides of the package between the first and second heating stages. The top of the package can also be heated after the second heating stage.
Claims10
An apparatus for processing a product and heat shrinkable film combination, the combination comprising:
- i. a product having a top surface, a side surface, and a bottom surface, the bottom surface further defining a front edge and a rear edge;
- ii. a heat shrinkable film which wraps around the top surface, the side surface and the bottom surface of the product and iii. optionally, a support which supports the product and which is located substantially between the product and the heat shrinkable film, the combination being processed by shrinking the heat-shrinkable film around at least a portion of the product as the combination comprising the product and the heat-shrinkable film moves through the apparatus, said apparatus comprising:
- a transportation mechanism for moving the product and heat-shrinkable film combination through the apparatus, the transportation mechanism causing the product and heat shrinkable film combination to move along a path having a beginning portion and an end portion;
- a first heat applicator means for applying heat to only an underside portion of the bottom surface of the product, the bottom surface portion being a distance from the front edge of the product of from about one tenth to about nine tenths of a package length, the package length being defined as the distance between the front edge and the rear edge of the bottom surface of the product, the first heat applicator being located along the beginning portion of the path of the product and heat-shrinkable film combination, the first heat applicator causing the heat-shrinkable film located substantially adjacent to the underside portion of the product to shrink, so at least a portion of the heat-shrinkable film moves from the top and the side of the product toward the bottom of the product;
- a second heat applicator for applying heat along at least a portion of the bottom and a portion of the sides of the product as the product moves along the end portion of the transportation mechanism, the second heat applicator being downstream from the first heat applicator, and the second heat applicator causing the shrink film to shrink further around at least a portion of the product.
A continuous, in-line process for heat shrinking a shrink film around an article having a front edge and a rear edge and a bottom surface comprising:
- moving the article wrapped with shrink film toward an apex,
- pivoting the article wrapped with shrink film over the apex,
- heating only an underside portion of the bottom surface of the article, the bottom surface portion being a distance from the front edge of the article of from about one tenth to about nine tenths of a package length, the package length being defined as the distance between the front edge and the rear edge of the bottom surface of the article, said heating of the underside portion occurring as the article pivots over the apex, and
- thereafter moving the article into and through a heated liquid bath.
Dependencies are inferred from the claim text.