EP0690011A1 - Floating metallic insert for a beverage container - Google Patents

Abstract

The insert consists of a chamber (3) with a hole (12) in its base which floats on the surface of the liquid. The insert is made from metal in the shape of a body with a skirt and a base (10) with a hole, fitted to the body with an annular seal. The edge of the body is turned over so that neither it, nor the edge of the base, comes into contact with the drink. The diameter of the rolled edge of the insert is between 1 and 4 mm with a skirt thickness of under 0.35 mm, and resists an inner pressure of over 0.6 MPa. The insert is made from aluminium or an aluminium alloy, and the hole in its base is equipped with a non-return valve in the form of a flexible strip held in place by adhesive. <IMAGE>

Description

FIELD OF THE INVENTION

The invention relates to the field of packaging of carbonated or carbonated drinks in easy-to-open packaging, typically beverage cans.
The pressure in these packages is generally higher than atmospheric pressure, and upon opening, bubbles are released and possible foaming. The invention relates to an insert to be introduced into the beverage can when packaging said beverage and intended to promote, by ejection of gas from the insert into said beverage, the formation of foam when opening said beverage can, in especially when said drink is beer.

STATE OF THE ART

Floating inserts are already known for this purpose. Such a floating insert is described in FIG. 2 of patent application WO 91/07326. It consists of an enclosure, made of plastic, weighted with a weight orienting said enclosure relative to the liquid plane of said drink, and comprising a single opening, located below the waterline, through which, during the opening of the box, the gas contained in the insert is injected into said drink.

The operation of such an insert is as follows: the opening is provided with closing means sensitive to the pressure difference between the internal pressure (in the insert) and the external pressure (in the container). This means may be a rupture disc or a valve which releases the gaseous content of the insert as soon as, when the container is opened, the pressure drops inside it.

In this type of insert, made of plastic, the deformation of the plastic insert during heat treatments, for example pasteurization, allow internal and external pressures to be balanced.
Furthermore, it is known that the inserts can operate with, as a closure means, an orifice of small dimensions (<0.5 mm in diameter).

PROBLEMS POSED

• a) d'une part, il est essentiel que l'insert flottant reste toujours correctement orienté par rapport à ladite boisson, sinon, il y a un risque que l'insert ne puisse plus jouer totalement son rôle comme propulseur de gaz au sein de ladite boisson lors de l'ouverture de la boîte boisson.
• b) d'autre part, il est indispensable que l'insert soit totalement neutre vis à vis de ladite boisson, c'est à dire qu'il n'y ait pas d'altération sensible des propriétés organoleptiques de ladite boisson, ni de migration de produits ou éléments chimiques de l'insert vers ladite boisson ou inversement de ladite boisson vers l'insert (extraction d'arôme).
• c) par ailleurs, il importe que l'insert ne complique pas le recyclage dedit récipient (boîte boisson) contenant un insert par rapport à celui de la boîte boisson seule.
• d) enfin, il est non moins essentiel que l'insert soit d'un coût de fabrication minime, le développement industriel et commercial des inserts étant en grande partie lié à cette question du prix de revient des inserts.

Floating inserts are much more convenient to use than those which use any assembly intended to precisely position the insert inside said container.
However, the known floating inserts pose problems of several kinds:

• a) on the one hand, it is essential that the floating insert always remains correctly oriented with respect to said drink, otherwise, there is a risk that the insert can no longer fully play its role as a gas propellant within said drink when opening the drink box.
• b) on the other hand, it is essential that the insert is completely neutral with respect to said drink, that is to say that there is no significant alteration of the organoleptic properties of said drink, nor of migration of products or chemical elements from the insert to said drink or vice versa from said drink to the insert (aroma extraction).
• c) moreover, it is important that the insert does not complicate the recycling of said container (beverage can) containing an insert compared to that of the beverage can alone.
• d) finally, it is no less essential that the insert be of minimal manufacturing cost, the industrial and commercial development of the inserts being largely linked to this question of the cost price of the inserts.

The Applicant has developed inserts which fully meet these four objectives, and which, by compared to the inserts of the prior art, significant progress on all of the plans considered, and in particular, in terms of the recyclability of the assembly "container plus insert", and in terms of manufacturing cost.

DESCRIPTION OF THE INVENTION

According to the invention, the floating insert, to be introduced into a container to contain a pressurized drink surmounted by a head space, intended to promote, when opening said container, the formation of foam on the surface of said drink, comprises an enclosure provided with at least one lower orifice, situated below the level of the liquid formed by said drink, allowing a transfer of gas from said enclosure to said drink, characterized in that, a) said enclosure is a metal enclosure formed by the assembly of a box body, consisting of a bottom and a side skirt, the end of which forms the opening of said box body, and of a cover, so as to close the opening of said can body with said cover, b) said cover is provided with said orifice, c) a peripheral seal, ensuring the tightness of said assembly, is positioned so as to prevent contact between said drink and the edges of said body d e box and said cover.

The Applicant first had the idea of a floating metal insert (MFI for short) designed so as to reduce its manufacture to an assembly of parts in themselves simple to manufacture, whether it is the body of box or lid intended to form said metallic enclosure.
She was surprised to note that despite the use of a metallic material, it was possible, also using inexpensive means which are easy to implement industrially, to maintain the migration of metallic ions at the - below the admitted threshold.

DESCRIPTION OF THE FIGURES

All the figures relate to the invention.
Figure 1 is a sectional view of a beverage can (18) with easy opening, filled with a beverage (19) on the surface (25) of which floats said metal insert IMF (1), formed by assembling a box body (3) and a converge (10), said box body being essentially surrounded by the head space (20), said cover, provided with a lower orifice (12) of small diameter, being immersed in said drink, and generally below the liquid level (25).

Figure 2 shows said cover (10), round, in a sectional view along a plane containing the axis of symmetry of the cover.
This cover (10) has an edge (11) intended for assembly with said box body (3), a re-entrant peripheral part (13) and a central part (14) forming a bowl and carrying said lower orifice (12) of 0.3 mm in diameter, intended for the passage of the gas flow during the opening of said container (18).

FIG. 3 represents a round box body (3) according to the invention intended to be assembled in a leaktight manner with the cover of FIG. 2 (sectional view along a plane containing the axis of symmetry of the box body).
This box body (3) consists of a bottom (4), a side skirt (5) having, a short distance from the end (6) of the skirt, a shoulder (8), surmounted by a portion of skirt (26) of low relative height, and on which said edge (11) of the cover (10) is intended to bear during the assembly of said cover (10) and said box body (3), via a peripheral seal (15).

Figure 4 is an enlarged view, in section similar to that of Figures 2 and 3, of the assembly of the cover (10) and the box body (3): the edge (11) of the cover is pinched between the rolled edge (9) obtained by rolling the end (6) of the skirt (5), and the shoulder (8) coated with a seal (15), so that the edge (21) of the edge of the cover and that (23) of the end of the box body are embedded in the material constituting the seal (15).

FIG. 5 represents a sectional view of an MFI constituted by the metal enclosure (2) formed by assembling the box body (3) and the cover (10), the method of assembly being that shown in enlarged Figure 4. In this figure are indicated different dimensions of the enclosure (2): the large diameter D, the small diameter d, and the height H.

Figures 6 and 6a, similar to Figure 4, illustrate other means for removing the slices (21,23) in contact with said drink, or, in Figure 6, by inserting a peripheral seal (15) between the edge of the cover (11) and the rolled edge (9), or, in FIG. 6a, by masking the edge (23) of the box body by a more accentuated rolling of the end (6) of the skirt (5).

Figures 7a and 7b show an alternative assembly by crimping said box body and said cover, by rolling the curved edge (11a) of said cover around the fallen edge (6a) of said box body, curved edge externally and carrying a ring joint (15), so as to ensure, after crimping, the tightness of said assembly, and to drown at least the edge (21) of the edge of said cover (10), as well as the edge (23) of the end of the box body.

FIG. 8a, similar to FIG. 1, shows in section a MFI according to the invention comprising a lower orifice (12) and an upper orifice (7), each of these orifices, with a diameter of the order of 1 to 3mm, being provided with a non-return valve, referenced (17) for the lower orifice (12), and (16) for the upper orifice (7).
FIG. 8b represents an example of a non-return valve, comprising a flexible strip (27) fixed by an adhesive (28) to the outside of the cover, so as to allow the exit of the gas flow from the insert to said drink. On the other hand, the non-return valve (16) of the upper orifice (7) is fixed to the inner surface of the bottom (4), so as to allow only one flow inlet from the head space towards the inside the insert.

DETAILED DESCRIPTION OF THE INVENTION

According to the invention, said peripheral seal (15) can be positioned in different ways depending on the type of assembly, so as to prevent contact between said drink (19) and the edges (23,21) of said can body and said lid.

According to a first method of assembly, said assembly is formed by pinching the edge (11) of said cover (10) between a shoulder (8) of said side skirt (5) and an internally rolled edge (9) of said end ( 6) of said skirt (5).

In this case, as shown in FIG. 4, said peripheral seal (15) adheres to the interior face of said shoulder (8) and of the skirt portion (26) comprised between said shoulder (8) and said end (6), so that said edges (21,23) of said cover and said box body are embedded in said seal (15).

As shown in Figure 6, said peripheral seal (15) can also form a tight bead between said edge of the cover (11) and said internally rolled edge (9). In this case, the sections (21,23) are not embedded in the joint as in the previous case.

FIG. 6a represents a variant of FIG. 4, where only the edge (21) of the cover is embedded in the joint, while the edge (23) of the rolled edge (9) is not, counts given the higher rolling in this case.
The rolled edge (9) must have a diameter between 1 mm and 4 mm, for a skirt end of thickness less than 0.35, so as to withstand a relative internal pressure greater than 0.6 MPa.
In fact, when the container is opened, a large pressure difference suddenly develops on either side of the metal enclosure (2) forming the MFI, which can cause the rolled edge to "unwind" ( 9), and consequently the ineffectiveness of said insert.

According to a second assembly mode shown in FIGS. 7a and 7b, said assembly is formed by crimping the edge (11a) of the cover with the end of said skirt forming a fallen edge (6a), said peripheral seal (15) adhering to the outer surface of said fallen edge (6a), so that at least said edge (21) of said cover is embedded in said seal.

To strengthen the certainty of always having an MFI (1) with adequate orientation, it is preferable to have an MFI (1) in which the section of said insert is, at its largest diameter D or D '(see Figures 5, 6, 6a, 7b), at least 15% greater than the section of said insert at said bottom.
Another complementary means contributing to making the orientation of the MFI (1) more reliable, consists in choosing the weight of the cover (10) at least equal to 0.5 times that of the box body (3).
For this, it suffices to start from a thicker metal strip to make the cover than to make the box body.
This reinforces the "tilting" effect of the MFI, in the sense that the MFI always tends to regain its optimum orientation, whatever the efforts exerted tending to tilt it sideways.

The Applicant has studied the impact of the shape of the cover on the stability of the MFI, in particular during the opening of said container.
The Applicant has observed that the shape of the cover could also make a contribution to the solution of the problem posed.
Following his observations, it is preferable that said cover comprises a re-entrant peripheral part (13) intended to facilitate centering of said cover (10) relative to said side skirt (5).
For unclear reasons, a cover as described above has led to more stable and better oriented MFIs - that is to say MFIs always repositioning themselves in the desired way ("tumble effect") - than those obtained, for example, with a cover comprising a flat central part.
It is possible that the reentrant peripheral part (13) plays a stabilizing role by the liquid ring formed trapped under said reentrant peripheral part (13).
The Applicant has observed that this preferred configuration of cover very greatly reduces the tendency of prior art MFIs to "take off" when the container (18) is opened by the propellant effect of the gas jet leaving the MFI. . According to a hypothesis put forward by the applicant, the re-entrant peripheral part (13) would lead to a "suction cup" effect tending to "join" - perhaps by wetting effect and surface tension - the base of the MFI and its element surrounding liquid.
Furthermore, the re-entrant peripheral part (13) of the cover also appears advantageous to facilitate the assembly of the cover (10) with the box body (3) and the centering of one relative to the other, centering which contributes to guarantee a good orientation of the MFI.
In addition, in the case of the configuration shown in Figures 4 and 6a, this re-entrant peripheral part (13) allows, by pressing against the shoulder (8) during assembly of the cover and the box body, to obligatorily creep the seal (15) upwards, and thus to drown in the seal (15) at least the edge (21) of the cover, if not the edge (23) of the rolled edge (9).

The MFI according to the invention can also have two orifices, a lower orifice (12) on the cover (10), and an upper orifice (7) on the bottom (4) of the box body (3). In this case, as shown in Figures 8a and 8b, these orifices are provided with non-return valves. FIG. 8b represents a typical non-return valve, made of inert elastomeric material.
These valves are mounted so as to close said orifices only in one direction, with respect to said metal enclosure: in the "outside ->inside" direction for the upper non-return valve (16), in the "inside -> outside direction. "for the lower non-return valve (17).

Such a device permanently ensures the balance of internal and external pressures (= head space pressure (20)) of the MFI, avoids filling the MFI with said drink, while allowing the MFI to play its full role when opening said container.
The upper (16) and lower (17) valves can be either identical or different, each of them being adapted to its own environment (head space or drink).
Other non-return valve configurations are possible according to the invention insofar as they allow the aims of the invention to be achieved.

According to the invention, said metal enclosure (2) is made of aluminum or aluminum alloy, or of steel, and is coated with a protective layer, generally a layer of varnish or sometimes a layer of plastic film, forming a barrier for said drink.

Generally, the same metal is chosen for the MFI (1) and for the container (18), which can therefore be made of aluminum or aluminum alloy, or steel.

According to the invention, said metal enclosure is preferably made of aluminum or aluminum alloy.

The interior volume of said metal enclosure (2) is related to the capacity of said container (18), and is preferably between 0.005 and 0.02 times the interior volume of said container.
Thus, by way of example, said insert has an internal volume of 7 cm³ (volume between 6.8 and 7.2 cm³) for an internal volume of said container of 500 cm³.

Preferably, said box body (3) and said cover (10) adapted to said box body, therefore said final IMF, are of round shape, for reasons of ease of manufacture and stability of orientation of the MFI, and said IMF has a height H / outside diameter D ratio measured at said rolled edge, or of the largest diameter, between 0.4 and 1. See FIG. 5.

• a) on forme, par emboutissage à partir de métal en bande revêtu d'une couche protectrice, un couvercle (10) muni d'un orifice (12) et d'un bord (11) adapté audit corps de boîte (3), et un corps de boîte (3) présentant un épaulement (8), l'épaisseur dudit métal en bande destiné à former ledit couvercle (10) étant supérieure à celle dudit métal en bande destiné à former ledit corps de boîte(3),
• b) on dépose un joint (15) sur ledit épaulement dudit corps de boîte (3),
• c) on assemble ledit couvercle (10) et ledit corps (3), par pincement du bord dudit couvercle entre un épaulement de ladite jupe latérale et un bord roulé intérieurement de ladite extrémité, de manière à ce que les tranches (21,23) dudit couvercle et dudit corps de boîte soient protégées par ledit joint.

Another object of the invention is a method for manufacturing the MFIs according to the invention.
This process includes the following steps:

• a) a cover (10) provided with an orifice (12) and an edge (11) adapted to said box body (3) is formed by stamping from metal strip coated with a protective layer; and a box body (3) having a shoulder (8), the thickness of said strip metal intended to form said cover (10) being greater than that of said strip metal intended to form said box body (3),
• b) a seal (15) is deposited on said shoulder of said box body (3),
• c) assembling said cover (10) and said body (3), by pinching the edge of said cover between a shoulder of said side skirt and an internally rolled edge of said end, so that the edges (21,23) said cover and said box body are protected by said seal.

To assemble said cover (10) and said body (3), it is advantageously possible to roll said edge internally while pressing against said cover, so that, in particular thanks to the elasticity of said seal, the edge of the box body does not damage, during the rolling phase, said protective layer covering said cover.
In addition, in order to facilitate said support, a die can support said shoulder during the interior rolling of said edge.

EXAMPLE OF IMPLEMENTATION

• 1) On a fabriqué des corps de boîte (3), comme représenté à la figure 2, avec les dimensions portées sur la figure 3, par emboutissage de bande métallique en alliage d'aluminium de 0,21 mm d'épaisseur.
  On a adapté un dispositif, utilisé pour le dépôt de joint à la périphérie des couvercles, pour déposer, sur l'épaulement (8) du corps de boîte, un joint (15), analogue au joint standard des couvercles de boîte boisson, et selon un profil de joint comme représenté sur la figure 2.
• 2) On a fabriqué des couvercles (10), comme représenté à la figure 2, avec les dimensions portées sur la figure 1, par emboutissage de bande métallique en alliage d'aluminium de 0,50 mm d'épaisseur. On a percé un orificé (12) de 0,3 mm de diamètre.
• 3) On a obtenu les IMF finals en assemblant les corps de boîte et les couvercles, à l'aide d'une sertisseuse modifiée de manière à former un bord roulé (9) comme représenté à la figure 5.

Figures 1 to 8b show non-limiting examples according to the invention.
The example of MFI shown in Figures 1 to 5 is carried out as follows:

• 1) Box bodies (3) were made, as shown in FIG. 2, with the dimensions shown in FIG. 3, by stamping a metal strip of aluminum alloy 0.21 mm thick.
  A device has been adapted, used for depositing a seal at the periphery of the lids, for depositing, on the shoulder (8) of the can body, a seal (15), similar to the standard seal for beverage can lids, and according to a joint profile as shown in Figure 2.
• 2) Lids (10) were made, as shown in FIG. 2, with the dimensions shown in FIG. 1, by stamping a metal strip of aluminum alloy of 0.50 mm thick. A hole (12) 0.3 mm in diameter was drilled.
• 3) The final MFIs were obtained by assembling the box bodies and the covers, using a crimper modified so as to form a rolled edge (9) as shown in FIG. 5.

Results obtained: The MFIs obtained were tested using two methods.

On the one hand, they have been tested in drink cans (easy-open cans) with a capacity of 500 cm³. For this, they were first introduced into beverage cans when packaging beer, then subjected to the standard pasteurization treatment.
The effect of the MFIs was then evaluated, by a person skilled in the art of brewing, when opening the beverage cans, by the quality of the foam obtained (finesse, persistence, etc.). This effect was deemed completely satisfactory by this skilled person.
On the other hand, to visualize the behavior of MFIs with regard to the problem of the stability of their orientation, MFIs were tested and observed using a device comprising a transparent container, similar to a container (18 ), and containing an IMF (1), this container can be oriented in all directions and can simulate the various situations (shocks, pasteurization, opening of the box, etc.) to which the drink boxes are subjected.
It was observed that the MFIs according to the invention exhibited a remarkable "tumble" effect, great orientation stability, including, which is important, when the box was opened.
It is thanks to this type of device that the configuration and the dimensions of the MFIs according to the invention have been selected, numerous tests having been carried out before arriving at the general and particular means of the invention.

Furthermore, analyzes of the aluminum content in beer have shown that protecting the edges (21,23) of the edge of the lid and of the can body made it possible to considerably reduce the metal ion content in said drink. It is possible to further reduce this content, either by protecting, in a manner known per se, and typically with a varnish, the edge of said orifice (12), or by using valves (17) which protect the edges of the orifices, as shown in Figure 8b.

ADVANTAGES OF THE INVENTION

The invention makes it possible to solve all of the problems posed, whether it is the technical efficiency of the MFI, its chemical inertness during a prolonged stay in said drink, or its cost of manufacture highly reduced compared to the inserts of the prior art.

Furthermore, the production of MFIs only uses standard technology from packaging manufacturers, requiring only stamping tools adapted to the shape of the box body and of the cover of the metal enclosure, which is another advantage of the invention.

An additional advantage of the invention lies in the choice of the metallic material constituting the essential of the MFIs. In fact, since beverage cans are generally recycled, especially when they are made of aluminum alloy, the use of MFIs made of the same metal or alloy as that of the beverage can allows on the one hand to exclude practically any risk corrosion by the effect of an electrochemical cell between the two materials, and above all facilitates the recycling of the metal from the "beverage can + insert" assembly.

Claims (13)

Floating metal insert (1), to be introduced into a container (18) intended to contain a pressurized beverage (19) surmounted by a head space (20), intended to favor, during the opening of said container, the formation of foam on the surface of said drink, comprising an enclosure (2) provided with at least one lower orifice (12), located below the level of the liquid (25) formed by said drink, allowing a transfer of gas from said enclosure (2) towards said drink (19), characterized in that, a) said enclosure (2) is metallic and formed by the assembly of a can body (3), consisting of a bottom (4) and d 'a side skirt (5) whose end (6) forms the opening of said box body, and of a cover (10), so as to close the opening of said box body with said cover, b) said cover (10) is provided with said lower orifice (12) c) a peripheral seal (15), ensuring the tightness of said assembly, is positioned so To prevent contact between said drink (19) and the edges (23,21) of said can body and said cover. Insert according to claim 1 wherein said assembly is formed by pinching the edge (11) of said cover between a shoulder (8) of said side skirt and an internally rolled edge (9) of said end (6) of said skirt. Insert according to claim 2, in which said peripheral seal (15) adheres to the inner face of said shoulder (8) and of the skirt portion (26) included between said shoulder and said end, so that said edges (21 , 23) of said cover and of said box body are embedded in said seal (15). The insert of claim 2 wherein said seal (15) forms a tight bead between said edge (11) of the cover and said internally rolled edge (9). Insert according to any one of Claims 2 to 4, in which the diameter of said rolled edge (9) is between 1 mm and 4 mm, for a skirt end of thickness less than 0.35 mm, so as to withstand pressure inner relative greater than 0.6 MPa. Insert according to claim 1, in which said assembly is formed by crimping the edge of the cover (11a) with the end of said skirt forming a fallen edge (6a), said seal (15) adhering to the external surface of said fallen edge (6a ), so that at least said edge of said cover (21) is embedded in said seal. Insert according to any one of Claims 1 to 6, in which the section of said insert (1) is, at its largest diameter D or D ', at least 15% greater than the section of said insert at said bottom. Insert according to any one of Claims 1 to 7, in which the said cover (10) has a re-entrant peripheral part (13) intended to facilitate the centering of the said cover (10) relative to the said side skirt (5). Insert according to any one of Claims 1 to 8, in which the weight of the cover (10) is chosen at least equal to 0.5 times that of the box body (3), preferably by using a thicker metal strip to manufacture said cover. than that used to manufacture said box body. Insert according to any one of Claims 1 to 9, in which the said metallic enclosure (2) is made of aluminum or aluminum alloy. Method of manufacturing an insert according to any one of Claims 1 to 5 and 7 to 10 comprising the following steps: a) a cover (10) provided with an orifice (12) and an edge (11) adapted to said box body (3) is formed by stamping from metal strip coated with a protective layer; and a box body (3) having a shoulder (8), the thickness of said strip metal intended to form said cover (10) being greater than that of said strip metal intended to form said box body (3), b) a seal (15) is deposited on said shoulder of said box body (3), c) assembling said cover (10) and said body, by pinching the edge of said cover between a shoulder of said side skirt and an internally rolled edge of said end, so that the edges (21,23) of said cover and of said box body are protected by said seal. A method according to claim 11 wherein, in step c) of said method, said edge is rolled internally while pressing against said cover (10), so that, in particular thanks to the elasticity of said seal (15 ), the edge (23) of the box body does not damage, during the rolling phase, said protective layer covering said cover (10). The method of claim 12 wherein, in order to facilitate said support, a die supports said shoulder during the interior rolling of said edge.

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