Related Art Fresh food articles that are transported over large dis- tances, and thereby over longer periods of time, from the producer to the buyer, degrade in various degrees. Com- mon for all food articles is that the share of products that are spoiled, and therefore have to be thrown away, increases over time, at the same time as the remaining share of the products also are degraded. This results in large economic losses for the involved parties.

As a counter measure to limit the loses, it is suggested that the transport time is reduced, that the properties of the food articles are altered in order to make them last longer, or that the transport methods and associated environment are developed in such a way that that the products do not degrade to the same degree. The present invention relates to a method and device that concerns the latter of the solutions.

The transport time cooperates together with factors such as temperature, air moisture and the composition of the

surrounding air. By modifying these factors, the preser- vation time can be prolonged considerably. Cooling is one well known preserving method that is extensively used.

Modifying the air composition has also proven to preserve the food articles. E. g., by lowering the content of oxy- gen in the air around some food articles, the preserva- tion time of some products can double several times. The various food articles have various optimal air composi- tions that prolong the preservation time optimally.

One problem with modified air composition is that the ex- isting system of containers, trucks, and pallets are so well-established, that the cost of investment potentially can become unduly high. The present invention presup- poses few or no changes of the existing transport equip- ment, and can be adapted to most kinds of boxes, crates, pallets, etc..

By wrapping the cargo with an entirely or partly air and moisture impermeable plastic membrane, and thereafter filling the defined enclosure by a suitable gas admix- ture, the enclosed cargo will be situated in an enclosure with a modified air composition until the enclosure is punctured. This wrapping can be done manually or auto- matically. By wrapping the cargo manually, the packing results have shown to vary greatly. Also, the manually wrapping in most instances takes an unacceptably large amount of time.

Objects of the Invention One object according to the present invention is to give directions for a method and device for automatic packing, that not only ensures the quality of the end result, but also cuts down on time used for the packing. Further- more, another object according to the present invention is obtain a packing method that rationally and effec- tively combines packing and air admixture.

Introduction of the Invention In the present invention, these objects are met by means of a method and device according to the characteristics disclosed in the characterizing clause of claim 1 and 10, respectively. Further characteristics and advantages of the present invention will be readily obtained by refer- ence to the following detailed description, when consid- ered in connection with the accompanying drawings, and the accompanying claims.

Short Description of the Drawings Fig. la and fig. 1b shows a side view and a top view, re- spectively, of a packing installation according to the present invention; Fig. lc shows a perspective view of the cargo, consisting of boxes or crates, and where the various plastic mem- branes are to be applied; Fig. 2 is a perspective view showing further details of the packing installation in accordance to Fig. la and lb, particularly the area where the individual cargo is packed;

Fig. 3a shows a perspective view of a detail of a par- ticular embodiment of a gas injection device according to the present invention; Fig. 3b shows, on a larger scale, some further details of the gas injection device in Fig. 3a; Fig. 3c shows the view in Fig. 3b in perspective; Fig. 4 is a perspective view of the packing area and shows a first embodiment of holding members, these pro- viding a relative movement between the enveloped cargo and the base; Fig. 5 is a top view, on a larger scale, showing some further details of the holding members according to Fig.

4; Fig. 6a is a side view of the packing area and shows an other embodiment of holding members providing relative movement between the enveloped cargo and the base, the cargo being shown in a first, tilted position; Fig. 6b is a side view similar to Fig. 6a, the cargo be- ing shown in an opposite, tilted position; Fig. 7 shows a side view of the packing area and illus- trates details of a first embodiment of a device for cov- ering the lower discharge end of the gas enclosure around the cargo;

Fig. 8 shows a side view similar to that in Fig. 7, but illustrates a further embodiment of a device for covering the lower discharge end of the gas enclosure around the cargo.

Detailed Description By reference to Fig. la-lc, Fig. 2, and Fig. 3a-3c, a description of an installation to which the present in- vention can be applied will be disclosed in the follow- ing. After the boxes, crates etc. la-ln have been filled with the desired articles of food, and they have been piled on a base 17, preferably a pallet, the pallet with cargo 12 is led on rolls 2 into a packing installation 1, which in a preferred embodiment comprises a gas injection organ 3 and a wrapping device 4. The wrapping device 4 wraps a membrane 21 around the cargo 12. The packing de- vice 1 further comprises a device for the introduction of at least one piece of plastic membrane (23,23') between the cargo and the pallet, a device 5 for the application of at least one piece of plastic membrane on top of the cargo, devices for the sealing together of the various plastic membrane elements, and a control device 26 that controls the process.

When the pallet 17 with the piled cargo is positioned into the installation 1, as shown in Fig. 2, the wrapping device 4 begins to wrap the cargo with the membrane 21 from the top edge 10 and downwards. At about the same time, a gas injection organ 3 is led to the top of the cargo 12, in a manner that covers the whole top surface, and then starts to inject the preferred gas admixture.

The increasing gas enclosure 16, that is created by the enveloping membrane 21, is filled by the injected gas ad- mixture and the ambient air already present in the enclo- sure is displaced by the injected gas admixture by means of its higher pressure. The degree of membrane overlap- ping, number of membrane layers, and/or the sequence the wrapping device 4 utilizes, is in advance related to the food article, gas admixture, and other factors that have to be optimized in order to obtain the best possible re- sult.

When the side surfaces 18 of the cargo 12 are enveloped more or less to the bottom and the created gas enclosure is filled with gas, the surface 13 between the cargo and the pallet also has to be covered by at least one piece of membrane 23, and this membrane 23 has to be sealed to- gether with the membrane 21 on the side surfaces, see, e. g., Fig. 7 or 8.

In one embodiment, the membrane 23 is placed on top of the pallet before the cargo is piled and then later turned up on top of the membrane 21 and sealed by means of a sealing device.

However, in a preferred embodiment, a membrane introduc- tion device introduces at least one piece of membrane be- tween the cargo and the pallet while the cargo is sepa- rated entirely or partly from the pallet by means of a separating organ, after which the separating organ brings the cargo and the pallet together again. This process can be executed before, during and/or after the membrane wrapping/gas injection is initiated.

Fig. 4 and 5 shows a first embodiment of holding members 8,9 that hold on to the cargo while the pallet 17 is lowered. These holding members 8,9 can partly or en- tirely surround the enveloped cargo, or they can grab onto one or more of the planar side surfaces, or onto one or more corners.

Fig. 6a and 6b shows a second embodiment of a separating organ comprising tilting organs 7,7', that first sepa- rate one part of the bottom surface of the enveloped cargo 12 from the pallet 17 and then, by tilting the cargo back thereupon further in the opposite direction of the first tilting direction, separate the other part of the bottom surface of the enveloped cargo from the pal- let.

As the one part of the bottom surface of the enveloped cargo is separated from the pallet, a membrane 23'is in- troduced into the split 17a by means of an introduction device, and as the other, opposite part of the enveloped cargo is separated from the pallet, a second membrane 23''is introduced into the split 17b by means of the same or an other introduction device. The membranes 23', 23''must be of such a size that that they overlap each other below the cargo and in addition stick out far enough around the cargo for them to be turned up over the side surfaces 18 and sealed by means of a sealing device (shown in Fig. 7 and 8). The tilting organs and the packing installation 1 in general is designed and con- structed to accommodate the gas injection organ 3 in a

firm position on top of the top surface 14 of the cargo, and can inject gas during the entire tilting operation.

The tilting organs comprises at least two surfaces 27, 27'that are brought to two opposing sides of the envel- oped cargo, where upon a first surface 27 pushes, or pos- sibly rotates, the cargo into a tilted position, while the other surface 27'follows the first surface in a par- allel manner and supports some of the weight, in order to limit the load on the bottom corner edge 14 of the envel- oped cargo that is in contact with the pallet. After both membranes 23', 23''are introduced, the cargo is tilted back into the upright position.

When the side surfaces 18 of the cargo are covered by the membrane 21, and the membrane 23, or membranes 23', 23'l, is or are placed where it, or they, is supposed to in a desired manner, either by placing the membrane on the base 17 before piling or by later introduction by means of the aforementioned introduction device, the ends 24 that stick out around the cargo have to be sealed by means of a membrane that covers the side surfaces.

Fig. 7 shows a mechanism for turning up the ends 24 that stick out around the cargo, comprising at least one me- chanical arm, the arm being equipped with at least one metal surface acting as a support surface that can hold up the ends 24. Fig. 8 shows blowing organs 25 that blows air in such a manner that the ends 24 are turned up along the side surfaces of the cargo. Either way, the aforementioned wrapping device 4 seals the ends 24 up against the membrane covered side surfaces 18 by applying

at least one layer of membrane around the bottom part of the cargo, in such a way that the applied membrane covers and tightens over the lap joint between the ends 24 and the covered side surfaces 18.

At this point the gas injection stops. The application device 5, that in a preferred embodiment is located on, and therefore moves together with, the device that holds the wrapping device 4, finds a suitable position with re- gards to the gas inlet end 14 of the cargo and the gas injection organ 3. A small overpressure created in the gas enclosure 16 gives the application device 5 time to cover the top surface 14, and the wrapping device 4 time to seal the top edges in much the same manner as the aforementioned bottom edge, after the removal of the gas injection organ 3, without altering the gas composition in the gas enclosure to any significant degree.

When all surfaces are covered or wrapped, the created gas enclosure 16 filled with a suitable gas admixture, and all lap joints and openings sealed, the cargo is ready for transport and a new pallet with cargo can undergo the same treatment.

The invention is not restricted to the exemplary embodi- ments described. Numerous modifications and variations are possible in light of the aforementioned. It is therefore to be understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein.