WITH PERFORATION OF THE CONTAINER

Description

This invention relates to a special method through which it is possible to obtain modified atmosphere packs, consisting in the perforation of the container.

Mainstream sealing machines come with a frame, an incoming conveyor belt, a first intermittent belt, according to the invention disclosed in patent EP 0334266 B2, a sealing station, an outgoing continuous-operation conveyor belt. The aforementioned mainstream sealing machines usually incorporate a film web coil, which is positioned upstream of the sealing station, provided with a film uncoiling device. In particular, the lower mould of the sealing station moves the container towards the film and subsequently presses the container and the film against the sealing plate, which is positioned on the upper mould of the sealing station. Here usually comes a coil that gathers the excess waste film. This coil is positioned downstream of the sealing station and the sealing machine. In particular, as vacuum packaging is concerned, within the sealing station where product-loaded containers are moved, air is evacuated from it and vacuum is generated. The system disclosed in this invention is based on that every container is perforated within the sealing station and thanks to this perforation, vacuum is generated or gas is injected.

This procedure is performed according to these steps.

The lower mould of the sealing station (1), where containers to be sealed are already arranged, approaches the upper mould of the sealing station (2), beneath which the cover film is already available (7).

The lower mould of the sealing station (2) gets in contact with the upper mould of the sealing station (1) where the sealing plate (3) is positioned. That will maintain the containers and the cover film (7) in close contact and pressed to each other, between the upper mould of the sealing station (1) and the lower mould of the sealing station (2). In this condition, some needles (4), provided in any number and position, are operated from the bottom upwards and perforate every container (5) (6), creating a hole for passage between the inside of the container and the chamber beneath the container, which is part of the lower mould of the sealing station (2). The needle (4) is hollow and has a tapered shape that makes it possible to obtain a hole by cutting and raising an edge, but without removing it completely. This is extremely important because no piece of container must be broken away and remain inside the packed product.

After holes are obtained, air within the container is evacuated by means of a vacuum generator and packing gas (modified atmosphere) is injected. When the needle is extracted, the cover film (7) is sealed onto the container.

At this point, the mould opens and sealed containers are extracted.

The system is based on the following devices:

1. lower mould of the sealing station;

2. upper mould of the sealing station;

3. sealing plate;

4. perforating hollow needle;

5. transparent container;

6. mat container;

7. cover film.