Heat-shrinking furnace for the formation of bundles with improved film adhesion

Abstract

A heat-shrinking furnace for forming bundles of products wrapped in a heat-shrinkable film and defining at least one channel for advancement of the bundles along an advancement direction, and including: an inlet fed by the bundle of products in succession one after the other, the products being tunnel-wrapped in a loose manner by the heat-shrinkable film to identify two lateral openings orthogonal to the advancement direction; an outlet for release of the bundles of products wrapped in a compact manner by the heat-shrinked film; a heater operating between the inlet and outlet for making heat-shrinking of the film on the products; and wherein in an intermediate position between the inlet and the outlet the furnace includes a mechanism for temporarily holding the heat-shrinkable film spaced apart from the products at the lateral openings during heat shrinking.

1 .- 10 . (canceled) 
     
     
         11 . A heat-shrinking furnace for forming bundles of products wrapped in a heat-shrinkable film, the furnace defining at least one channel for advancement of the bundles along an advancement direction, and comprising:
 an inlet fed by the bundles of products in succession one after the other, the products being tunnel-wrapped in a loose manner by the heat-shrinkable film to identify two lateral openings orthogonal to the advancement direction;   an outlet for release of the bundles of products wrapped in a compact manner by the heat-shrinkable film;   heating means operating between the inlet and the outlet for making the heat-shrinking of the film on the products; and   in an intermediate position between the inlet and the outlet, means for temporarily holding the heat-shrinkable film spaced apart from the products at the lateral openings during heat-shrinking, the means for temporarily holding the heat-shrinkable film spaced apart from the products at the lateral openings during heat-shrinking comprising means for generating an air blow that is at least partially directed along the advancement direction, the means being arranged in an intermediate position between the inlet and the outlet at both lateral walls of each advancement channel, so that the blows, by penetrating into the lateral openings of the heat-shrinkable film wrapped in a loose manner on the containers, hold the heat-shrinkable film temporarily spaced apart from the products at the lateral openings;   wherein the means for generating an air blow, which is at least partially directed along the advancement direction, comprises, for each wall of the channel, a blowing device directed towards a deflecting element arranged on the respective wall, the deflector being configured for reflecting the blow towards the openings.   
     
     
         12 . A furnace according to  claim 11 , wherein the walls are fed by air along substantially their entire development and include holes for supply of the air into the channel substantially in a direction orthogonal to the advancement direction, the means for temporarily holding the heat-shrinkable film spaced apart from the products at the lateral openings during heat-shrinking comprises deflectors arranged in an intermediate position between the inlet and the outlet at both lateral walls of each channel to direct, where present, air exiting from the walls at least partially along the advancement direction so that the air, by penetrating into the lateral walls of the heat-shrinkable film wrapped in a loose manner on the containers, holds the heat-shrinkable film temporarily spaced apart from the products at the lateral openings. 
     
     
         13 . A method for heat-shrinking for forming bundles of products wrapped by a heat-shrinkable film, the method comprising:
 feeding into a heat-shrinking furnace in succession one after the other a bundle of products, which is tunnel-wrapped in a loose manner by the heat-shrinkable film to identify two lateral openings orthogonal to the advancement direction;   heating the film during advancement of the bundle into the furnace for making the heat-shrinking of the film on the products;   releasing the bundles of products wrapped in a compact manner by the heat-shrinked film;   holding the heat-shrinkable film temporarily spaced apart from the products at the lateral openings during heat-shrinking;   wherein the holding the heat-shrinkable film temporarily spaced apart from the products at the lateral openings during heat-shrinking includes generating an air blow at least partially directed along the advancement direction so that the blows penetrate into the lateral walls of the heat-shrinkable film wrapped in a loose manner on the containers; and   wherein the generating an air blow which is at least partially directed along the advancement direction so that the blows penetrate into the lateral walls of the heat-shrinkable film wrapped in a loose manner on the containers includes supplying an air blow directed towards a deflector element arranged on the respective wall, the deflector being configured to reflect the blow towards the openings.   
     
     
         14 . A method according to  claim 13 , wherein the holding the heat-shrinkable film temporarily spaced apart from the products at the lateral openings during heat-shrinking is made through reflection of an air flow exiting from the walls.