Cooling Holes for Film Wrapped Articles

Abstract

Holes in the film can be formed after film wrapping the bundle. Slits are formed in the heat shrink film prior to film wrapping the bundle. While the bundle moves through a heat shrink tunnel on a conveyor, the slits can be opened by increasing the shrinkage of the film surrounding the slit. This can be accomplished by directing high speed jets of hot air on the slits. Although slits are preferred the hot air can be used on any opening to increase the size of the opening.

Description

FIELD OF INVENTION

This invention relates to cooling or freezing an article or a bundle of articles after the article has been filmed wrapped and heat shrunk. The term article refers to a bundle of articles such as bottles or a single article. These articles are perishable and require a cooled environment.

BACKGROUND OF INVENTION

The prior art has placed articles in cartons, having holes in the carton, to allow cold air to circulate in the carton during the freezing or cooling of the articles. This technique of cutting holes in the heat shrink film for air circulation of the article has been tried without success. Cutting the holes mechanically with an heated die or heat while the heat shrink material is moving resulted in hole sizes of less than about ⅜ inch. The prior art was in need of a commercial viable way of creating openings large enough to allow sufficient air circulation to cool or freeze articles wrapped with a heat shrunk film.

The prior art, shown in U.S. patent application Ser. No. 13/972,078 filed on Aug. 21, 2013 by Alain Cerf titled, Cooling film Wrapped Articles, is incorporated by reference in the entirety. The application shows forming slits or slots in the longitudinal direction in a heat shrink film for allowing cooling air to circulate between the articles while maintaining the structural integrity of the heat shrunk film. This invention was not always able to achieve openings of sufficient size for allowing cooling air to circulate between the articles

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows a film 1 moving between a set of rollers 2 and 3. Adjustable blade 7 on pivot 6 is lowered to cut a slit in the film. The location and the length of the slit is formed so that when a bundle of articles are film wrapped the slit 4 is located on the vertical sides of the bundle. FIG. 2 shows three vertical slits 4 and three vertical slits 5 to be located on opposing vertical sides of the bundle. After film wrapping the bundle moves through a heat shrink tunnel on a conveyor where the film is heat shrunk. Within in the tunnel, the slits are opened by increasing the shrinkage of the film surrounding the slit. This can be accomplished by directing high speed jets of hot air on the slits. Openings in excess of 20-25 mm can be achieved. FIG. 3 shows cups of yogurt 7 having opened slits using jets of hot air.

After the film is heat shrunk, the wrapped article is transported to a freezer or cooler 7 to prevent spoilage of the contents within the bundle. The heat shrunk bundle can be bundled or palletized prior to entering the freezer or cooler.

Claims

1. A process for arranging an article or a bundle of articles wrapped with heat shrink film so that cool air can circulate through the bundle comprising,

forming a slit in the film,

locating the slit so the slit is positioned on the vertical sides of the bundle during film wrapping, film wrapping the bundle,

transporting the wrapped bundle to a heat shrink tunnel, heat shrinking the bundle, and

increasing the opening of the slit during heat shrinking by increasing the heat shrinkage of the film surrounding the slit.

2. A process according to claim 1 including cooling the film wrapped article to prevent spoilage.

3. A process according to claim 1 including multiple vertical slits located on opposing vertical sides of the bundle.

4. A process according to claim 1 wherein high speed jets of hot air are directed on the slit during heat shrinking of the film.

5. An apparatus for arranging an article or a bundle of articles wrapped with heat shrink film so that cool air can circulate through the bundle comprising,

means for forming a slit in the film,

means for locating the slit so that the slit is positioned on the vertical sides of the bundle during film wrapping,

means for film wrapping the bundle,

means for transporting the wrapped bundle to a heat shrink tunnel,

means for heat shrinking the bundle, and

means for increasing the opening of the slit by increasing the heat shrinkage of the film surrounding the slit.

6. An apparatus according to claim 5 including means for cooling the film wrapped article to prevent spoilage.

7. An apparatus according to claim 5 including means for forming multiple vertical slits on opposing vertical sides of the bundle.

8. An apparatus according to claim 5 wherein means for directing high speed jets of hot air on the slits during heat shrinking of the film.

9. A process for arranging an article or a bundle of articles wrapped with heat shrink film so that cool air can circulate through the bundle comprising,

forming an opening in the film,

film wrapping the bundle,

transporting the wrapped bundle to a heat shrink tunnel,

heat shrinking the bundle, and

increasing the size of the opening during heat shrinking by increasing the heat shrinkage of the film surrounding the opening.

10. A process according to claim 9 wherein the opening is a slit.

11. A process according to claim 9 wherein the heat shrinkage of the film is increased by directing high speed jets of hot air on the film surrounding the opening during heat shrinking of the film.