Package making – With contents treating – Vacuum or inert atmosphere
Reexamination Certificate
1998-11-09
2001-02-13
Johnson, Linda (Department: 3721)
Package making
With contents treating
Vacuum or inert atmosphere
C053S510000, C053S556000
Reexamination Certificate
active
06185913
ABSTRACT:
The invention relates to machines for the packaging with stretchable film of products normally previously disposed in trays, and concerns improvements to enable these machines to form packages containing a modified and controlled atmosphere, with the aim of better conservation of the packaged product. The term “modified and controlled atmosphere”, or more simply “modified atmosphere”, denotes at least any one of the following conditions:
a) an atmosphere different from the external ambient atmosphere, consisting of one or more gases suitable for the conservation of the packaged product and having the same pressure as the external atmosphere;
b) an atmosphere different from the external ambient atmosphere, consisting of one or more gases suitable for the conservation of the packaged product and having a pressure greater than the external atmospheric pressure;
c) an atmosphere identical to the external ambient atmosphere but at a markedly lower pressure, typical of the packaging called “vacuum packaging”;
d) an atmosphere different from the external atmosphere, formed by one or more gases suitable for the conservation of the packaged product and having a pressure markedly lower than the external pressure, typical of the packaging called “vacuum packaging”.
The packaging of the products with stretchable film is at present generally carried out with a gas-permeable film. However, stretchable gas-tight films are available at present on the market.
This patent application tackles the technical problem of how to be able to provide any machine for packaging products with stretchable film, for example the machine described in U.S. Pat. No. 3,967,433 (Bonfiglioli), capable of producing packages containing a modified atmosphere, suitable for the purposes of conserving the product.
To resolve this problem, according to the known art of the packaging of products with gas-tight, heat-sealable, but not stretchable film, it is necessary, at the moment of formation of the packaging around the product, before its closure, to evacuate with suitable means the air inside the package, and, if necessary, to introduce the modified atmosphere into the package which at the correct time is heat-sealed and closed so that it is gas-tight. The machines using these known solutions are slow and of complex construction and doubtful reliability, since it is extremely difficult to control precisely the phases of evacuation of the ambient air from the package and of any refilling of the said package with the modified atmosphere.
In the known art, the modified atmosphere, when it consists of gases other than those of the ambient atmosphere, is generally prepared in advance from time to time according to the type of product to be packaged and is stored in a container from which it is taken gradually in the necessary quantity. When the machine has to package a type of product different from that of the preceding cycle, it is necessary to replace the storage container which supplies the modified atmosphere. It is evident that this condition impedes the rapid adaptation of the machine to the packaging of different products.
Packaging machines using stretchable film have a high output per hour, and would therefore be adversely affected by the aforesaid known solutions. In order to be able to produce packages with stretchable gas-tight film, under a vacuum and/or containing a modified and controlled atmosphere for the conservation of the product, it has been necessary to devise a new solution which would be easily applied, would have high technological reliability, and, above all, would allow the packaging machine to operate at a high speed. According to the invention, the formation and closure of the package with stretchable film are carried out in a main chamber with means which maintain in it a modified atmosphere according to at least one of the aforesaid four conditions a), b), c), d). It is evident that the packaging cycle is simplified, since it is not necessary to use the present means which operate selectively on individual packages and it is possible to use an ordinary packaging machine with stretchable film. Each package is provided internally with the atmosphere modified for the purposes of the conservation of the product, since the same package is formed and closed in an environment which is completely filled with the modified atmosphere. The product enters and leaves the said main chamber by passing through corresponding entry and exit airlock chambers which are provided with corresponding doors for sealing with respect to the external environment and which are connected to the said main chamber. When the outer sides of the entry and exit chambers are opened, their inner sides are closed, in such a way that modified atmosphere does not issue from the main chamber. Before the inner doors which connect the entry and exit chambers to the main chamber are opened, the outer sides of these chambers are closed, and means may be provided to “evacuate” the ambient atmosphere from them and if necessary to introduce the modified atmosphere into them.
In the equipment according to the invention, when the packaging of the product has to be carried out in a modified atmosphere, the main chamber is also made to be connected to a plurality of storage containers, each containing the primary gases which participate in the formation of the modified atmosphere for the conservation of the product, and mixing means are provided to control the supply of the gas from the said containers and may be programmed so that the atmosphere required from time to time for the conservation of the products to be packaged is formed and maintained in the packaging chamber and if necessary also in the airlock chamber. This solution permits a simple and rapid adaptation of the machine to the packaging of different products which require controlled atmospheres having different characteristics.
The closest prior art know to applicant is repersented by document FR-A-1 343 586. According to this document, there is disclosed a method and apparatus for filling and closure of metallic drums with liquid substances in a sterilized environment. Apart from the different scope, clearly the apparatus according to the said prior art document differs in a substantial manner from the equipment in accordance with the present invention, as it will appear evident from the following description.
REFERENCES:
patent: 1770379 (1930-07-01), Young
patent: 2763107 (1956-09-01), Day et al.
patent: 3996725 (1976-12-01), Walles
patent: 4707334 (1987-11-01), Gerhard
patent: 4944132 (1990-07-01), Carlsson et al.
patent: 5001886 (1991-03-01), Turtschan
patent: 5371998 (1994-12-01), Johnson et al.
patent: 206096 (1986-12-01), None
patent: 1343586 (1962-09-01), None
patent: WO 94/10041 (1994-05-01), None
Cappi Angelo
Rimondi Renato
A.W.A.X. Progettazione E Ricerca S.r.l.
Johnson Linda
Larson & Taylor PLC
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