EP0732275B1 - Package for packaging and preserving fresh goods - Google Patents

Abstract

The package consists of a tray (1) which receives a perforated false bottom on which the feed product rests, and a film covering layer. The false bottom rests on a series of ribs (8a - 8h) projecting from the surface of the tray which give it rigidity and allow for the collection of fluids exuding from the food product. The ribs are positioned, for example, so that their tips lie perpendicular to the sides of the tray, and at least some of them are linked to form closed cavities. The tray is made from a thermoplastic material such as polystyrene, polyethylene, PVC, PET, and the film covering can be of polyethylene, thermo-shrink polyethylene, PET or similar.

Description

The present invention relates to a new device for packaging and preserving fresh food products, intended in particular for meat, seafood products and the like which tend to exude liquids which promote the proliferation of bacterial flora inside a transparent film. which envelops and isolates the product / packaging unit from the outside.

Such packaging devices have been known for a long time, consisting of a tray of synthetic material such as polystyrene, on which the product to be presented is placed, the assembly being wrapped in a transparent impermeable film such as polyethylene.

The appearance of these devices coincides with the advent of supermarkets with self-service fresh produce departments. The current trend, based on the growing development of mass distribution, is to multiply the products offered by this route which has the advantage of avoiding the consumer queues in front of meat or seafood stalls, which is often appreciated during peak hours.

However, this conditioning technique encounters a double problem in its development.

Thus, in the first place, it is known that the fresh products thus presented, namely the butchery, tripe, delicatessen, fishmonger's products and the like have often retained the reputation of being less fresh than the products sold to the market. stall, of so that buyers do not always rely on the sales and consumption deadlines that appear on packaging.

This reputation is linked at least in part to the appearance of these products through the transparent film which constitutes the only means of protection of the product presented on the tray, and it is true for example that the sight of a meat placed on a tray stained with blood, or the bottom of which is soiled with exudate, makes the appearance of the product unattractive to the consumer.

This drawback is even more marked in the case of a tray containing a fish fillet resting on its exudate, which is particularly unappetizing.

Various solutions have already been proposed to overcome this difficulty.

Thus, the patent application PCT-WO-86 07036 describes a container of this kind in which the exuding product, for example a meat, is placed on a first element or false bottom comprising openings and welded directly on parallel rectilinear ribs of '' a second element or background, so as to allow the exuded product, for example the blood, passing through these openings to be collected in a space between the two elements, in order to remove the blood from the view of the buyer , to overcome the aforementioned drawback.

These parallel rectilinear ribs define compartments which are parallel to each other between the two elements, that is to say in which said exuded product, although forced to remain in said compartments when the container is tilted by tilting about an axis parallel to said ribs, on the other hand, can freely accumulate on one or the other of the two other perpendicular sides of the container when the latter is inclined around an axis perpendicular to said ribs.

As a result, if the exudate is well removed from the view of the consumer, it nevertheless remains with its risks and drawbacks.

Another solution consists in placing the product under consideration in contact with a material having absorbent properties. It would not be advisable to use for this purpose a tray whose bottom would be absorbent, because it would preserve on the one hand an appearance as evoked above, and because the humidity of the material, which would be constantly in contact with the product, would aggravate the problem of preservation and risk degrading said support material due to the pressure of the product filmed on the tray.

In this case, therefore, provision has been made for trays with a non-absorbent bottom, but to discharge the exudates, a false bottom receiving the product present at regular intervals of the orifices of small dimensions opening onto an absorbent material, for example of the blotter type, placed under said false bottom. The blotter itself rests on the bottom of the tray, so that there are three successive layers forming, in cooperation with the final filming, the packaging device.

• Une feuille supérieure, destinée à être au contact du produit, et percée d'orifices régulièrement espacés sur deux rangées.
• Une feuille intermédiaire, absorbant les liquides, et
• Une feuille constituant l'enveloppe externe, de même nature que la première, et destinée à supporter le filmage.

This is for example the solution described in patent application PCT-WO-92 08610, consisting in constituting a package from three sheets each having its own characteristics:

• A top sheet, intended to be in contact with the product, and pierced with regularly spaced orifices in two rows.
• An intermediate sheet, absorbing liquids, and
• A sheet constituting the outer envelope, of the same kind as the first, and intended to support filming.

However, such packaging still has drawbacks, the most important being that the intermediate layer has no residual space to swell if the volume of liquid flowing through the orifices proves to be significant.

In addition, as the three layers are pressed against each other, there is no volume of air between the support layer and the outer envelope, which would allow immediate regeneration of the air contaminated by the flora. bacteria appearing in the absorbent layer after a certain period of humidity. It is therefore the air surrounding the filmed product which carries out the permanent exchange with the soaked tampon, so that it too degrades gradually.

Finally, the absorbent layer inherently extends the wet area over the entire possible surface, depending on the volume of liquid passing through the orifices and the absorbency of the pad / blotter. The latter therefore tends to propagate the very cause of the preservation problem encountered in such packaging.

We must therefore consider that this first problem has not yet been satisfactorily resolved.

The second problem related to the packaging technique considered is mechanical in nature.

Indeed, in many cases, the transparent film is of the heat-shrinkable film type, that is to say having the property, on heating, of reducing dimensions by pressing against the periphery of the volume that it surrounds. This technique is widely used for the packaging of many products, and it has the advantage of immobilizing a product on its support, and above all eliminating a large part of the air enveloped in the film before heating, thus subtracting a food product to the action of oxygen.

However, this retraction has the consequence of subjecting the wrapped product - and therefore, in fact, the tray - to a strong peripheral stress, which tends to deform said tray, in particular by buckling along its largest dimension. This tendency is all the more accentuated as the bottom of the tray is made of material as thin as possible, both to reduce the weight of the tray and for economic reasons.

Instead of this technique, use is also made, to fix the film, of welding said film around the periphery of the upper edge of the tray, the film being, in this case, generally under tension, which creates a phenomenon similar to the previous one. .

In any event, and even without this peripheral constraint, the weight of the product contained in the tray tends to cause its deformation, especially in the case where this product is relatively large, for example if it s is a flat fish.

The only solutions proposed to this problem consisted in stiffening said bottom by means of grooves coming from molding.

Thus, Australian Patent No. 631,520 describes a packaging for meat, the elements of which, namely a bottom and a false bottom, each include reinforcing ribs. These ribs serve, in the event of impact, to prevent absorbent material, contained in sachets housed in a space situated between said two elements, from being released by the rupture of these sachets.

In addition, it is mentioned that the ribs of the false bottom and the ribs of the bottom are perpendicular, but in fact the two sets of ribs are superimposed and their role is only to stiffen and strengthen separately the bottom and the false bottom, and this each in a unique direction.

The document PCT-WO-8607036 already cited also includes ribs in only one direction, helping to provide stiffening preferentially longitudinally to the product.

Document US-A-3,563,445 describes a tray with chevron ribs, said rafters having branches oriented diagonally relative to said tray. At the ends, sections perpendicular to the sides connect the rafters to the outer edges. This configuration essentially provides diagonal stiffening, in two main directions not parallel to the longitudinal and transverse axes of the tray. Secondarily, a stiffening blank takes place at the side edges. It is always a rigidification that could be described as discrete, in a reduced number of directions.

The document US Pat. No. 3,671,272 describes a tray provided with concentric grooves, in principle offering non-discrete stiffening, but developing in a random manner according to the arbitrary curves of the concentric ribs. However, said ribs were not provided for stiffening purposes, but to support a piece of sliced meat, and collect exudates from the slices. Secondly, it is noted that said grooves can help stiffen the tray.

None of the preceding documents systematically and rigorously envisages the double problem posed above, and none provides a truly satisfactory solution for solving them simultaneously. Conversely, the invention which is the subject of this document presents an approach which comprehensively addresses these problems.

The present invention relates to a new device in which means are provided for jointly and simultaneously solving the two aforementioned problems, namely eliminating the effects of any exudate released by a product packaged in a container of the aforementioned type, and making said container non-deformable notwithstanding the stresses created in particular by the film enclosing said product in said tray.

• d'un fond imperméable relativement rigide, et
• d'un faux fond sur lequel vient reposer ledit produit et comportant des orifices pour lesdits liquides, ledit faux fond reposant sur des reliefs dudit fond, en définissant un certain nombre de compartiments fermés, l'invention consiste en ce que, en vue d'assurer simultanément une rigidification isostatique dudit fond et la récolte contrôlée desdits liquides exsudés dans lesdits compartiments, lesdits reliefs sont répartis suivant au moins un réseau de nervures sensiblement parallèles entre elles, chacune desdites nervures s'étendant le long d'au moins deux directions de manière telle que d'une part elle présente en chaque point une orientation dans laquelle elle résiste à une composante correspondante de la contrainte périphérique créée par la pellicule thermorétractée, et d'autre part, une extrémité d'une nervure est perpendiculaire à un côté du fond et l'autre extrémité est perpendiculaire à un côté adjacent.

To this end, in a device for the packaging and preservation of fresh food products such as meat, seafood and the like, tending to exude liquids promoting the proliferation of bacterial flora, which thus mimic the duration of authorized consumption, the type comprising a container for the product to be packaged and a heat-shrinkable plastic film enclosing said product in said container, and consisting of, fitted one inside the other,

• a relatively rigid waterproof bottom, and
• of a false bottom on which rests said product and comprising orifices for said liquids, said false bottom resting on reliefs of said bottom, by defining a number of closed compartments, the invention consists in that, with a view to simultaneously ensuring isostatic stiffening of said bottom and controlled harvesting of said liquids exuded in said compartments, said reliefs are distributed along at least one network of ribs substantially parallel to each other, each of said ribs extending along at least two directions so such that on the one hand it has an orientation at each point in which it resists a corresponding component of the peripheral stress created by the heat-shrunk film, and on the other hand, one end of a rib is perpendicular to one side of the bottom and the other end is perpendicular to an adjacent side.

To fully fulfill their isostatic stiffening function, said ribs are therefore advantageously distributed in such a way that the orientation of each rib at each of its ends is substantially perpendicular to two adjacent sides of the bottom.

In general, the ribs can take any geometric shape. For example, they can have a polygonal appearance, in which case, according to the simplest embodiment, they can be formed of two branches joined together at an obtuse angle.

According to a possible variant, only a portion of the bottom comprises ribs, and another constitutes a continuous raised zone of the same height as the ribs, this zone possibly representing any fraction of the surface of the bottom.

However, according to a preferred embodiment, these ribs have a rounded shape, and more especially they have a general shape of arcs of ellipses distributed according to four groups corresponding to the four zones rectangular of the bottom defined by its two axes of symmetry, each of these elliptical arcs having an elongated shape, one of its ends being located along one side of the bottom or in the vicinity and being substantially perpendicular to this side, and the other end being located along an adjacent side and being substantially perpendicular to that side, said compartments having a corresponding rounded elongated shape.

According to the invention, it results from this configuration of the reliefs, on the one hand that the bottom is made practically non-deformable even under the action of the peripheral stresses created by the heat shrinkage of said film, and on the other hand that all of said compartments constitutes a network in each of the meshes from which opens at least one of said orifices, in order to channel, isolate and immobilize therein as many individual fractions the portion of said liquids having passed through the false bottom by said orifices by preventing said fractions from moving throughout volume by being likely to accumulate in one area or another, where they could contaminate the said product.

This double consequence of the aforementioned configuration of the reliefs therefore simultaneously provides a solution to the two problems mentioned above.

In practice, said reliefs, or ribs, can take various aspects, since, at each point, from one of its ends to the other, thanks to its curvature, each rib will contribute to buckling resistance from the bottom in the direction corresponding to the location of this point.

Thus, said ribs may be concave or convex towards the outside of the bottom surface. They can remain each individual or join in pairs or four. In each case, the compartment created between two consecutive ribs will simply be elongated in general elliptical shape from one edge of the bottom to the adjacent edge, or in the shape of a curvilinear V or in the shape of a curvilinear rectangle or square, it being understood that, preferably according to the invention, each compartment must correspond to at least one orifice of the false bottom.

In addition, each orifice extending downwards by a frustoconical flow chute, it is provided, according to the invention, to initiate by capillarity said flow, to practice in the upper surface of the false bottom, an inclined channel opening into the '' upper mouth of each orifice, the depth of this channel increasing in order to reach, at the location of said orifice, the height of said chute.

The invention therefore ensures the evacuation of the exudate from the conditioned product and its fractionation into small volumes immobilized between the bottom and the false bottom out of any contact with said product. Insofar as some of these small compartments, due to geometric considerations, can keep a certain length, over which a small fraction of exudate could still travel, it follows from the rounded shape on which this path would be made, that this fraction would spread and adhere along the rounded wall of this compartment without the risk of accumulating at any point in the volume between the bottom and the false bottom.

To further reduce the volume of exudate reaching said compartments, it is also possible to associate with the container, between the false bottom and the upper portion of the ribs supporting this false bottom, an intermediate buffer allowing this area to be used at least partially, both for absorption purposes and for better conservation by gas exchange with said zone.

Such a buffer can contain, in addition to hydrocaptrating substances, other antibacterial and / or hydroreactive substances regenerating the atmosphere and contributing to the conservation of said products after packaging.

• La figure 1 est une vue en perspective d'un mode de réalisation préféré du dispositif selon l'invention, ne contenant aucun produit,
• La figure 2 est une vue en perspective du fond seul,
• La figure 3 est une vue en perspective du faux fond seul,
• La figure 3a est une coupe agrandie d'un orifice du faux fond,
• La figure 4 et la figure 5 sont des coupes verticales de la figure 1, le long des deux plans de symétrie du dispositif, avec interposition d'un tampon absorbant entre le faux fond et le dessus des nervures,
• La figure 4a est un fragment agrandi de la figure 4, faisant apparaître la disposition relative du faux fond avec ses orifices et dudit tampon absorbant,
• La figure 6 est une vue de dessus du fond de la barquette, avec l'indication de l'emplacement des trous du faux fond et de l'orientation des rigoles qui leurs sont associées,
• Et la figure 7 est une variante de la figure 6 selon un autre mode de réalisation.

Other characteristics and advantages of the invention will appear in the following description, corresponding to the appended drawing, in which:

• FIG. 1 is a perspective view of a preferred embodiment of the device according to the invention, containing no product,
• FIG. 2 is a perspective view of the bottom only,
• FIG. 3 is a perspective view of the false bottom alone,
• FIG. 3a is an enlarged section of an orifice of the false bottom,
• FIG. 4 and FIG. 5 are vertical sections of FIG. 1, along the two planes of symmetry of the device, with the interposition of an absorbent pad between the false bottom and the top of the ribs,
• FIG. 4a is an enlarged fragment of FIG. 4, showing the relative arrangement of the false bottom with its orifices and of said absorbent pad,
• FIG. 6 is a top view of the bottom of the tray, with the indication of the location of the holes of the false bottom and of the orientation of the channels which are associated with them,
• And Figure 7 is a variant of Figure 6 according to another embodiment.

In all the figures, the same reference numerals denote the same constituent elements of the. device according to the invention.

As can be seen in FIG. 1, the device according to the invention is made up in a known manner of a rigid waterproof bottom 1 and a false bottom 2 comprising perforations 3, the bottom 1 and the false bottom 2 being joined together along their periphery 6, by welding or fitting, so as to provide between them a hermetic space 7 appearing in FIGS. 4 and 5.

According to the invention, and as it appears in particular in FIGS. 2 and 6, the bottom 1 comprises, from the molding, ribs which are referenced, on one of the quadrants of the bottom, from 8 _a to 8 _h , from the outside (corner C ₁ ) towards the center. On the other three quadrants, symmetrically, the same ribs are provided.

To seal the space 7, the false bottom can be welded both on its periphery and on top of each rib.

• Ainsi, les nervures 8_a, 8_b se rejoignent en 9 par l'une de leurs extrémités sur l'un des bords 10 du fond 1, tandis que leurs extrémités opposées 11_a-11_b sont écartées vers le bord adjacent 12 du fond 1.
• De même, les nervures 8_c, 8_d se rejoignent en 13 par l'une de leurs extrémités sur le bord 10, tandis que leurs extrémités opposées 14_a, 14_b sont écartées vers le bord 12.
• Par contre, la nervure 8_e rejoint la nervure symétrique 8_e' du quadrant symétrique correspondant au coin C₂ en un point 15 situé sur le bord 10, tandis que son autre extrémité 16 est sur le bord 12.
• De même, l'une des extrémités de la nervure 8_f rejoint en 17 la nervure symétrique 8_f' du quadrant C₂, tandis que son autre extrémité rejoint en 18 la nervure symétrique 8_f'' du troisième quadrant C₃.
• De même encore, les nervures 8_g et 8_g' se rejoignent en 19 à une extrémité et les nervures 8_g et 8_g'' se rejoignent en 20 et les nervures 8_h, 8_h' et 8_h'' se rejoignent en 21 et 22, les points de rencontre 17, 19, 21 étant orientés vers le côté 10, mais dans l'intérieur de la surface du fond 1 et les points de rencontre 18, 20, 22 étant orientés vers le côté 12, mais également dans l'intérieur du fond.

These ribs all have a general elliptical appearance, but take various aspects depending on their location on the bottom surface.

• Thus, the ribs 8 _a , 8 _b meet at 9 by one of their ends on one of the edges 10 of the bottom 1, while their opposite ends 11 _a -11 _b are separated towards the adjacent edge 12 of the bottom 1.
• Likewise, the ribs 8 _c , 8 _d meet at 13 by one of their ends on the edge 10, while their opposite ends 14 _a , 14 _b are spread towards the edge 12.
• On the other hand, the rib 8 _e joins the symmetrical rib 8 _{e '} of the symmetrical quadrant corresponding to the corner C ₂ at a point 15 located on the edge 10, while its other end 16 is on the edge 12.
• Similarly, one end of the rib 8 _f joins at 17 the symmetrical rib 8 _{f '} of the quadrant C ₂ , while its other end joins at 18 the symmetrical rib 8 _f'' of the third quadrant C ₃ .
• Similarly, the ribs 8 _g and 8 _{g '} meet in 19 at one end and the ribs 8 _g and 8 _g'' meet in 20 and the ribs 8 _h , 8 _h' and 8 _{h ''} join in 21 and 22, the meeting points 17, 19, 21 being oriented towards the side 10, but in the interior of the bottom surface 1 and the meeting points 18, 20, 22 being oriented towards the side 12, but also in the interior of the bottom.

According to these various aspects, the ribs 8 _a -8 _h define, between them and between the bottom 1 and the false bottom 2, compartments isolated from each other, and having either an elongated shape from edge 10 to edge 12, such as compartment 23 located between the ribs 8 _d and 8 _e , and compartment 24 located between the ribs 8 _b and 8 _c , or a shape open only on the side 12, such as compartment 25, opening between 8 _c and 8 _d , or a V shape such as 26 between the sides 12 and 27, and closing at 28 between 8 _th , 8 _f , 8 _{th '} and 8 _f' , or a closed curvilinear square compartment 29 defined between the four ribs 8 _g , 8 _{g '} , 8 _g'' , 8 _g''' .

The same configurations are found symmetrically on the four quadrants corresponding to the four corners C ₁ , C ₂ , C ₃ , C ₄ .

• complètement fermés,
• de petites dimensions,
• arrondis.

The essential characteristic of these configurations is that the compartments defined by the elliptical ribs between the bottom 1 and the false bottom 2 are:

• completely closed,
• small dimensions,
• rounded.

As a result, the small amount of exudate that can be collected in each compartment from the orifices 3 of the false bottom 2 is itself very small, completely isolated and immobilized from one compartment to the other, and that, by manipulation of the tray, can only travel along elongated and rounded paths along which it cannot accumulate but on the contrary be divided into even more tiny fractions. It is therefore completely impossible for the exudate to accumulate in any zone of the bottom 1, even by tilting the latter at a strong inclination, and all the more reason, to return to contact with the product placed on the false bottom.

However, the sections of FIGS. 4, 4a and 5 have shown an additional absorbent pad 30 placed under the false bottom 2, and which further reduces the amount of exudate reaching the preceding compartments through the orifices 3.

As shown in the enlarged view of FIG. 4a, in this case, said absorbent pad 30 is perforated to let through the orifices 3 which sink therein due to their frustoconical shape.

To channel the exudate towards the orifices 3, there is provided, according to the invention, at least one channel or flow initiator 31, which are shown in FIGS. 3, 3 a and 6.

These channels are triangular and of increasing depth so as to open out at level 31 'from the bottom of the orifice 3. These inclined channels are in number and arrangement such that they collect all the exudate and bring it to the orifices 3, which , as shown in Figure 6, are distributed above all the compartments 23, 24, 25, 26, 29 and the like defined by the ribs at the bottom. In addition, as it also appears in FIG. 6, the channels 31 are, for each orifice 3, oriented parallel to the direction of the corresponding compartment in order to initiate by capillarity the flow of the exudate in this compartment.

Conversely, this configuration of the orifices and channels has the effect that the exudates evacuate towards the hermetic space 7 even in the very inclined position of the tray presented to the customers, while each chute of an orifice 3 having a frustoconical shape, as best seen in Figure 3a, the exudate thus collected in space 7 can no longer return to the product resting on the false bottom 2, even if the tray is completely inverted.

• dans chaque compartiment, les exsudats sont séparés du faux fond ou du tampon absorbant par une lame d'air qui constitue une sorte de réservoir d'air frais améliorant la conservation ;
• Les conditionnements selon l'invention sont souvent inclinés lors de leur présentation sur les rayons des supermarchés. Si la totalité des exsudats pouvait se mélanger, comme dans les systèmes connus, ils se retrouveraient dans une zone inférieure où ils seraient à nouveau en contact avec le faux fond ou le tampon, empêchant celui-ci de sécher et y favorisant la prolifération bactérienne. Or, le produit repose sur le faux fond et ledit tampon, lorsqu'il existe, se trouve lui aussi pratiquement au contact du produit à protéger, va les orifices de passage. Ces derniers autorisent bien entendu le passage dans les deux sens, de sorte que, dans ces systèmes connus, en cas de saturation du tampon dans ladite zone latérale, un passage de liquide pourrait avoir lieu vers le produit ; cela est rendu impossible selon l'invention.
• Les volumes d'air des compartiments peuvent coopérer avec des substances contenues dans la couche intermédiaire, lorsqu'elle est prévue, par exemple un hydrocapteur inhibiteur des flores bactériennes générées par le produit. Le tampon se trouvant entre deux réserves d'air placées de part et d'autre réagit différemment de celui qui n'est au contact que d'un volume d'air entourant le produit.

This segmentation of exudate into small isolated volumes is very important for many reasons:

• in each compartment, the exudates are separated from the false bottom or the absorbent pad by an air knife which constitutes a sort of fresh air reservoir improving the preservation;
• The packaging according to the invention is often tilted when presented on supermarket shelves. If all the exudates could mix, as in the known systems, they would be found in a lower zone where they would be again in contact with the false bottom or the buffer, preventing the latter from drying and promoting therein the proliferation of bacteria. However, the product rests on the false bottom and said buffer, when it exists, is also practically in contact with the product to be protected, goes through the orifices. The latter of course allow passage in both directions, so that, in these known systems, in the event of saturation of the buffer in said lateral zone, a passage of liquid could take place towards the product; this is made impossible according to the invention.
• The air volumes of the compartments can cooperate with substances contained in the intermediate layer, when it is provided, for example a hydrosensor that inhibits the bacterial flora generated by the product. The buffer being between two air reserves placed on the side and others react differently from those who are only in contact with a volume of air surrounding the product.

It should be noted that certain packaging is done under a modified atmosphere, and that the buffer can then also contain hydroreagents regenerating the atmosphere initially injected. It is then necessary to treat the atmosphere both around the product and in the hollow areas of the bottom.

The importance of the ribs in the creation of the compartments thus ensuring the segmentation of the exudate into isolated and immobilized portions of very small volume having thus been demonstrated, it should be noted that the same ribs also play a role of equal importance in the mechanical strength of the packaging according to the invention.

For convenience of description, we will explain in more detail below the usefulness of the ribs mechanically in the case of the use of a heat-shrinkable film, but it is understood that they fulfill the same role if the tray is closed by welding on the periphery of its upper edge with a non-shrinkable but stretched film, for example made of polyethylene, PVC, polyethylene terephthalate (PET) or the like, having barrier properties (liquid and gas tight) or not.

As recalled above therefore, the polyethylene film by which the packaged product is enclosed under vacuum on the false bottom of the package is generally of the heat-shrinkable type, that is to say that, after having wrapped the assembly in this film, this the latter is sealed by passage through a heated zone, which causes the shrinkage of the film which is applied tightly over the entire outer surface of the tray and its contents, expelling practically all of the air. The film is thus applied under tension, which has the effect, in addition to this vacuuming and this protection against the outside, of exerting at all points of said surface, a significant contraction stress.

This constraint does not affect the packaged product, but instead subjects the tray to a force exerted over its entire periphery towards the center. However, the tray is made for example by thermoforming a relatively very thin polystyrene sheet, for obvious economic reasons, so that its bottom is relatively flexible. Parallel rectilinear ribs, of the known type, can only stiffen this bottom in one direction, which means that said bottom can perfectly bend or twist in all other directions, under the peripheral action of the tension exerted by the shrunk film.

On the contrary, the ribs according to the invention oppose to this action a resistance oriented at each point in the direction of the stresses exerted on this point. Thus, in the areas adjacent to the two axes of symmetry of the bottom, the ribs are precisely oriented parallel to these axes, respectively in the longitudinal direction in the vicinity of the edge 10 and the opposite edge and in the transverse direction in the vicinity of the edge 12 and the opposite edge. In other words, the shape of the ribs opposes the buckling of the tray 1, in a longitudinal direction under the effect of the stresses exerted on the two short sides and transverse under the effect of the stresses exerted on the two long sides. At any intermediate point, each rib is opposed to the torsion of the bottom against the stress exerted at this point tangentially to said rib.

The pattern of ribs distributed in four elliptical quadrants on the bottom 1 therefore constitutes the ideal physical model for opposing any deformation of this bottom under the action of the peripheral stress exerted on this bottom.

Said ribs, with their shape and their distribution, therefore fulfill a double function, providing the solution to the double problem set out above.

They also perform other functions in the alternative.

Thus, if we consider the structure described in PCT-WO-86 07036 representing the state of the art recalled above, we must consider that the set of parallel rectilinear ribs relatively distant from each other which there is described, not only does not create small volumes capable of isolating and immobilizing minimal portions of exudate in all directions, but moreover does not provide support, on each side of the flow orifices provided in the false bottom, sufficient to prevent this false bottom from being deformed between two neighboring ribs. On the contrary, the pattern of close and rounded ribs according to the invention provides such support, which also guarantees the non-deformability of the false bottom under the weight of the packaged product.

Furthermore, as seen in particular in Figure 2, the ribs formed in the bottom 1 stop at a certain distance from the upper edge of this bottom. This allows convenient stacking and reduced size of the trays, each of which rests on the end of the ribs of the one below, thus preventing their blocking and facilitating their separation.

• de s'étendre depuis un bord du fond jusqu'au bord adjacent en étant sensiblement perpendiculaires aux bords d'où elles sont issues et où elles aboutissent, en suivant une courbe adaptée aux dimensions desdits bords : c'est pourquoi, cette courbe est de préférence un quart d'ellipse depuis un bord d'un rectangle jusqu'au bord adjacent,
• et d'être suffisamment rapprochées pour créer entre elles et entre le fond et le faux fond des volumes de dimensions suffisamment petites pour isoler et immobiliser des portions très petites d'exsudat, de l'ordre par exemple de 1-1,5 cm³.

Finally, it will be noted that the precise shape of the ribs according to the invention is not critical, although the preceding description has referred to elliptical ribs concave towards the four corners of the bottom, the same ribs could have the same shape, but with inverse concavity, that is to say convex towards the four corners, or even deviate from a mathematically perfect elliptical shape. The only overall imperative that the ribs according to the invention must comply with is:

• to extend from an edge of the bottom to the adjacent edge being substantially perpendicular to the edges from which they originate and where they terminate, following a curve adapted to the dimensions of said edges: this is why, this curve is preferably a quarter ellipse from one edge of a rectangle to the adjacent edge,
• and to be close enough to create between them and between the bottom and the false bottom volumes of dimensions small enough to isolate and immobilize very small portions of exudate, of the order for example of 1-1.5 cm ³ .

It is important to note in this regard that the volume of exudate is variable depending on the product packaged.

Thus, as very approximate examples, it can represent 1% of the weight of a slice of red meat, 3% of a slice of a piece of tripe, for example liver, and up to 5% d fresh fish, each of these weights corresponding to a volume related to the density of the exudate considered, for example blood or salt water.

In the case of a fish, if one admits very roughly that its exudate is comparable to salt water and that the density of salt water is approximately 1, a fish of 100 g will exude approximately 5 g of salt water, representing approximately 5 cm ³ , which is a proportionately considerable volume, taken as a whole.

A larger fish (or fish fillets) (e.g. 300 or 400 g) will exude a proportionally larger amount of exudate, but this overall amount will be subdivided into a larger number of small individual volumes, since the tray will also be greater.

This is why, the principle of the device according to the invention is based on a subdivision of this overall volume into a large number of individual volumes, isolated from each other, and proportionally much smaller, in contrast to the large volumes of devices such as that of PCT N ° 86 07036 cited first.

According to the invention, for an exudate, inevitably released from a product such as meat, tripe, fishmonger or the like, to represent no risk of pollution of this product, or a risk minimized as much as possible, the overall volume of this exudate is subdivided into individual individual volumes, each of which does not exceed, at most, about 1.5 cm ³ , and is preferably substantially less.

As also indicated, the false bottom can be adapted to the bottom by any process ensuring the tightness of the connection: welding, clipping and the like, preferably the assembly is such that the common flange 6 is oriented inwards at 32 for make handling of the trays more pleasant than if this rim is sharp and oriented towards the outside.

In addition, the absence of a sharp edge thanks to the turning 32 towards the inside will reduce the risks of cutting of the transparent film, thereby allowing the use of thinner film. This reversal will preferably be around 45 °.

It will be noted that, throughout the foregoing description, emphasis has been placed on the configuration of the geometric pattern formed by the ribs relative to the surface of the background. An essential aspect of the invention resides in fact in the orientation of said ribs relative to the periphery of said bottom. Thus, in the case of arcs of ellipses, it is clear that the ratio between the major axis and the minor axis of such ellipses will be all the higher the longer the length of the bottom is compared to its width.

Another essential aspect of the invention residing in the creation, between the bottom and the false bottom, of closed volumes delimited by successive ribs, it is clear that, depending on the height of the ribs relative to the bottom, such volumes will be more or less important for the same gap between the same ribs. This height being to be taken into account for the other effect of the same ribs, namely their stiffening effect on the bottom, it will therefore be necessary, in each practical embodiment, to find a compromise between the linear dimensions of the bottom and of the ribs and the height of said ribs, as well as, where appropriate, their own width which contributes to the seat of the false bottom, given the volume of liquid that is expected to exude from each packaged product. For example, such an exudate will represent a greater volume when it comes from a fish than when it comes from a slice of red meat, and the ribs will have to be higher to ensure the stiffening of a larger bottom, for example intended to receive a flat fish, such as a turbotin of 30 x 15 cm, instead of a tournedos of 20 x 10 cm.

It is therefore understood that, the invention essentially targeting said configuration of the ribs, any variant or dimensional modification made to said ribs will fall within the scope of the invention. It will be the same for the shape of the cross section of the ribs, which may also vary from one rib to another depending on the general configuration. It will also be the same for the effective number of ribs formed on a determined bottom, a portion of this bottom possibly comprising ribs according to the invention, and another constituting a continuous raised zone of the same height as the ribs, this zone being able to represent any fraction of the bottom surface, both in the central portion and on the periphery.

Finally, in the same spirit, we can consider that, according to another embodiment, each of the "elliptical arcs" as mentioned, is practically formed of two practically rectilinear sections, joining at an obtuse angle, as illustrated very schematically in FIG. 7, which differs from FIG. 6 only in the relatively rectilinear shape of the segments 40, 40 ', 41, 41', 42, 42 ', ... forming each of the ribs, the orientation and the configuration of these segments being equivalent to those of each elliptical arc according to claim 1, the connection angles 43, 44, 45 of said segments corresponding to an orientation of the segments 40, 41, 42 perpendicular to the sides 10 to that of the segments 40 ', 41', 42 ', perpendicular to the side 12, which from the point of view of stiffening of the bottom 1 is practically equivalent. The remarks relating to the dimensional relationships of the arcs of ellipses 8 are of course valid with respect to the segments 40.

In the same way as for the protective film, the bottom of the tray can be made by any technique and in all materials such as polystyrene, polyethylene, PVC, PET, forming a barrier or not.

Claims (18)

1. Package for the packaging and the preservation of fresh food, such as meat, sea products and the like tending to exude fluids favouring a rapid growth of bacterial flora limiting the selling deadline, being of the type comprising a tray on which rests the fresh product and a thermoretractable thin sheet of film material overwrapping said product in said tray, comprising:

   - A quite rigid and impermeable first container portion (1), and

   - A second container portion (2) on which the fresh product rests, fitted in the said first container portion, and including apertures (3) allowing the passage of the fluids,

      said second container portion (2) resting on corrugations or ribs (8) of the first container portion, to define a predetermined number of closed chambers, characterized in that, in order to allow an isostatic rigidification of the first container portion (1), and a controlled collecting of the fluids exuded by the product in said chambers, the ribs (8) are distributed according to at least one network of approximately parallel ribs (8a to 8h, 8a' to 8h', 8a'' to 8h'', ...), each one extending at least along two directions so that said rib (8) is in each of its points directed to resist to the corresponding component of the peripheral stress caused by the film material overwrapping the package, one end of each rib being perpendicular to one side (10) of said first container portion (1), while the other end is perpendicular to the adjacent side (12).
2. Package according to claim 1, characterized in that said ribs (40, 40', 41, 41', 42, 42', ...) have a polygonal shape, including two segments forming an obtuse angle.
3. Package according to claim 1, characterized in that said ribs (8a to 8h, 8a' to 8h', 8a'' to 8h'', ...) are curvilinear.
4. Package according to the preceding claim, characterized in that said ribs (8a to 8h, 8a' to 8h', 8a'' to 8h'', ...) take the generall shape of arcs of ellipses distributed into four groups (C1, C2, C3, C4) located in the four rectangular quadrants of said first container portion defined by the two axes of symmetry, each of the arc of ellipse being elongated, with one of its ends being located along or closely adjacent to one side (10), and the other end being located along the adjacent side (12), so that said chambers are also elongated and curvilinear.
5. Package according to any of the preceding claims, characterized in that said first container portion (1) keeps its shape, despite the stresses caused by the thermoretracted overwrapping film material, especially because of the ribs (8), said chambers constitute a network with meshes in which opens at least one aperture (3), in order to canalize, cut off and keep the part of the fluid having passed the innermost second container portion via said apertures (3) in many individual parts, preventing them from moving in the total space defined between said first and said second container (1, 2) portions, and from accumulating, where they could contaminate the packaged product.
6. Package according to one of the preceding claims, characterized in that each rib (8) extends from one side (10) of the first container portion (1) to an adjacent side (12) thereof, the ends thereof being approximately perpendicular to said sides (10, 12), and following a curve corresponding to the size ratio of said sides (10, 12), said ribs (8) being enough near to each other so that they define between themselves small volumes, the small size of which being adapted to cut off and stop small portions of the exudate, in the order of 1-1,5 cm³.
7. Package according to one of the preceding claims, characterized in that each chamber comprises at least one aperture (3) provided with a wall portion which extends towards the first container portion (1), and with at least one sloped drain (31) helping to start the flowing of the fluid in said apertures (3) by capillarity, the depth of the said drain (31) increasing to reach, at the location of the aperture (3), the length of said wall portion.
8. Package according to any of the claims 1 to 7, characterized in that, between the second container portion (2) and the uppermost surface of the ribs (8), it is provided an intermediate pad (30) using at least partially the area located between said first and said second container portions (1, 2), said pad (30) adapted to absorb fluids or to preserve better the fresh product by allowing a gazeous exchange with said area.
9. Package according to claim 8, characterized in that the sawn-off cone apertures (3) are provided in said intermediate pad (30), in holes perforated therein.
10. Package according to claim 8, characterized in that said pad (30) contains not only hydroretaining products provided for keeping the exudate, but also other antibacterial and/or hydroreagent products regenerating the atmosphere and contributing to the preservation of the fresh products.
11. Package according to any of the claims 1 to 10, characterized in that, said first container portion (1) being divided into four quadrants (C1, C2, C3, C4) by the two symmetrical axes, and said ribs (8) are distributed into four corresponding groups (8a to 8h, 8a' to 8h', 8a'' to 8h'', ...), the concavity thereof being oriented towards the respective corners.
12. Package according to any of the claims 1 to 10, characterized in that, said first container portion (1) being divided into four quadrants (C1, C2, C3, C4) by the two symmetrical axes, and said ribs (8) are distributed into four corresponding groups (8a to 8h, 8a' to 8h', 8a'' to 8h'', ...), the concavity thereof being oriented towards the center of the package.
13. Package according to any of the claims 1 to 12, characterized in that the ends of said ribs (8) are located at a certain distance of the upper edge of the first container portion (1), to facilitate the piling up of the trays and the parting of said trays.
14. Package according to any of the claims 1 to 13, characterized in that only one portion of said first container portion (1) comprises ribs (8), another portion being a raised area, at a height which is equal to the height of said ribs, this last portion covering any part of the surface of the first container portion (1).
15. Package according to any of the claims 1 to 14, characterized in that said first and second container portions (1, 2) are fixed together by means to provide tightness of the assembly, the edge of the latter being oriented inwardly, at about 45°.
16. Package according to any of the claims 1 to 15, characterized in that said first container portion (1) is formed of polystyrene, polyethylene, PVC, PET or the like.
17. Package according to any of the claims 1 to 16, characterized as including a thin transparent sheet formed of polyethylene, retractable polyethylene, PVC, PET or the like, capable of forming a barrier.
18. Package according to the preceding claim, characterized in that said thin transparent sheet is applied to the tray by thermoretraction or welding.

Images