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(11) | EP 1 932 763 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Packaging machine for MAP and skin packages |
| (57) The invention is related to a packaging machine which seals a film to a tray which
has been filled with a packaging item, for example food. The packages can be so-called
MAP packages in which the packaging item is packaged under a modified atmosphere.
In order to modify the atmosphere, the air is in a first step at least partially taken
out of the tray and then substituted by a modified atmosphere, for example N2 and/or CO2. An other package which can be produced on the traysealer is a so-called skin package
in which a top-film is shrunk around the packaging item, so that it butts against
the packaging item.
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[0002] The above-mentioned packaging machines are for example so called traysealers. Traysealers are machines which seal a film to a tray which has been prefabricated and filled with a packaging item, for example food. These packages can be so-called MAP packages (Modified Atmosphere Packages) in which the packaging item is packaged under a modified atmosphere. In order to modify the atmosphere, the air is in a first step at least partially taken out of the tray and then substituted by a modified atmosphere, for example N2 and/or CO2 or O2. An other package which is produced on a traysealer is a so-called skin package in which a top-film is shrunk around the packaging item, so that it butts against the packaging item. Packaging machines nowadays have to be very flexible.
[0003] It was therefore the problem of the present invention to increase the flexibility of packaging machines known from the state of the art.
[0004] The problem is solved by a packaging machine which seals a film to a tray, whereas it comprises means to produce MAP- as well as skin-packages without altering the machine.
[0005] It was totally surprising and could not have been expected by a person skilled in the art, that it is possible to produce MAP packages as well as skin packages on the same packaging machine without any need of reconstruction. Thus, MAP-packages and skin-packages can be produced on the same machine without hardly any downtime of the machine. This reduces the costs of production of the respective packaging items.
[0006] The packaging machine according to the present invention can be any packaging machine known by a person skilled in the art. However, preferably the packaging machine is a so-called traysealer in which a top-film is sealed to a tray which is filled with a packaging item.
[0008] A MAP-package is a package with an atmosphere different to air around the packaging item under the film. The air can be at least partially replaced by an inert gas, for example N2 or CO2 or by an oxygen enriched atmosphere.
[0009] A skin package according to the present invention is made by a shrinkable film which is sealed to the tray and shrunk around the packaging item so that it butts against the packaging item.
[0010] Preferably, the inventive packaging machine comprises a gas pipe which can be used alternatively as a gas supply or to draw vacuum.
[0011] Preferably, the packaging machine comprises a chamber which is formed by two dies which form a dieset. The dieset surrounds the tray as well as the film which is sealed to the tray. For the production of skin packages, the chamber is preferably diverted in separate upper chamber and a separate lower chamber. Most preferably, the separation is carried out by the film.
[0012] Preferably, the operator can select at the machine panel which type of package shall be produced; i. e. a MAP package or a skin package.
[0013] In the following the invention is further explained according to figures 1 - 3. These explanations do not limit the scope of protection.
Figure 1 shows the inventive packaging machine.
Figure 2 shows the inventive packaging machine according to figure 1 to produce MAP-packages.
Figure 3 shows the inventive machine according to figure 1 to produce skin-packages.
[0014] Figure 1 shows the inventive packaging machine 1. This machine comprises an upper die 2 and a lower die 3 which form a dieset. At least one of the dies can be moved vertically so that the dies form a chamber 19 (Please compare figures 2 and 3). In the upper die, a sealing tool 4 is located which is also vertically moveable relative to and independent from the upper die 2 and which seals the film (not depicted) to the tray 16. The rim of the tray 16 is located on an ambos 15 which is a counter bearing for the sealing tool 4. In the upper die 2, the tube 6 is located. This tube is connected with tube 17, in which a valve 14 has been arranged. In the lower die, a tube 7 is located, which is connected to the tube 10. Via tubes 10 and 7, a gas, for example nitrogen, carbon-dioxide, or oxygen can be blown into the chamber 19. Tube 10 is further connected with tube 9, in which a valve 13 has been arranged. Tubes 9 and 17 are connected to a vacuum pump 11, so that via tubes 6 and 7 air can be drawn out of chamber 19.
[0015] Figure 2 shows the embodiment of the inventive packaging machine to produce MAP packages. Therefore, a tray 16 is located on the ambos 15. Furthermore, a film 18 is introduced into chamber 19, which is formed by the upper die 2 and the lower die 3. As can be seen, there is a gap between the film 18 and the rim of the tray 16. After the dies have been moved together to form chamber 19, vacuum is drawn via tube 6 out of chamber 19 and consequently out of the tray 16. After a desired level of pressure has been reached, the valve 14 is closed and via tube 7, a gas different from air is introduced into chamber 19, which also fills the room of the tray above the packaging item (not depicted). Subsequently, the sealing tool 9 is moved downwards as depicted by arrow 8 and the film is sealed to the rim of the tray 16.
[0016] Figure 3 shows the embodiment of the inventive packaging machine which produces skin packages. In the present case, there is also a tray located on the ambos 15. In the present case, the film 18 has such a width, that it extends to the rim of the upper die 2 and the lower die 3, so that, when these two dies 2, 3 are moved together, the film 18 separates the chamber into an upper chamber 19' and a lower chamber 19". After the film 18 has been introduced into the dieset and the upper and the lower dies have been moved together, vacuum is drawn via tubes 16 and 17 from the upper chamber 19' by opening valve 14 while valve 13 remains closed. This reduces the pressure in the upper chamber 19', so that the film 18 is drawn against the heating plate 8 and is consequently heated. Next, valve 13 is opened to draw air out of the lower chamber 19" via tubes 7, 10, 9 to reduce the pressure in the lower chamber approximately to one mbar. In the next step, the chamber 19' is ventilated via a ventilation valve (not depicted), so that the heated film is pushed downwards and forms a skin around the packaging item. Simultaneously or afterwards, the film 18 is sealed to the tray 16 and cut from the film-roll. As the last step, the lower chamber 19" is ventilated, the dieset is opened and the package is removed from the dieset.
[0017] The person skilled in the art understands that no mechanical alteration of the packaging machine is needed to produce MAP or skin packages. By opening or closing valves 13, 14 and/or supplying a gas to chamber 19, MAP packages or skin packages can be produced on the inventive machine. Consequently, the operator can choose at the machine panel which type of package is produced, without changing the machine. Consequently, the downtime of the machine due to a change between skin or MAP packages is close to zero.
List of references:
1. Packaging machine (1) which seals a film (18) to a tray (16), characterized in, that it comprises means to produce MAP- as well as skin-packages without altering the
machine.
2. Packaging machine (1) according to claim 1, characterized in, that it comprises a gas-pipe (7) which can be used as a gas-supply or to draw vacuum.
3. Packaging machine (1) according to one of the preceding claims, characterized in, that it comprises a chamber (19) formed by the dieset (2, 3).
4. Packaging machine according to claim 3, characterized in, that for the production of skin-packages, the chamber is diverted into a separate upper
chamber (19') and a separate lower chamber (19").
5. Packaging machine according to claim 4, characterized in, that the film (18) separates the chambers (19', 19").
6. Packaging machine according to one of the preceding claims, characterized in that package type can be selected at a machine panel.