EP2177437B1 - Method and installation for manufacturing sealed packages for food products, and such packages - Google Patents

Abstract

The method involves forming an envelope from a blank for conferring bottom (5'') and side walls (5''') that define an opening, where the walls form upper flaps of the envelope. Food product is introduced into the envelope. A cover plate (6) is applied on the product so as to close the opening. The envelope is hot-sealed on the plate by folding and sealing the flaps on an outer face of the plate via induction heating of the envelope, where the sealing of the envelope is performed through hot activation of adhesive (6') at a sealing interface between envelope's inner face and the outer face. Independent claims are also included for the following: (1) a sealed package containing liquid or fluid food product, comprising an envelope (2) an installation for manufacturing a sealed package containing liquid or fluid food product.

Description

The present invention relates to a process for the production of sealed packaging of the closed envelope type with a lid and each containing a food product, in particular a liquid or pasty product, an installation for carrying out this process, and such packaging capable of be obtained by this process. The invention applies more particularly to mini-portions of fresh or melted cheese, mini cubes of broth or mini breads of butter, without limitation.

• soit de manière non étanche, avec des plis de fermeture non scellés assurant aussi l'ouverture (typiquement le cas d'une mini-portion de beurre, de fromage frais ou d'un mini cube de bouillon),
• soit de manière quasi étanche, au moyen d'une bandelette thermocollante simple ou double par exemple de type Tircel® qui est conçue pour permettre l'ouverture de l'emballage via une déchirure contrôlée réalisée par traction d'une de ses extrémités formant languette, pour l'obtention de plis de fermeture scellés quasi étanches (typiquement des mini-portions de fromage fondu).

In general, the machines for packaging mini-portions, whether they are square, rectangular, triangular or round, comprise an envelope or "shell" possibly surmounted by a lid forming lid and can be folded :

• either in an unsealed manner, with unsealed closing folds also ensuring the opening (typically the case of a mini-portion of butter, fresh cheese or a mini cube of broth),
• or in a substantially watertight manner, by means of a single or double heat-sealing strip for example of the Tircel® type which is designed to allow the opening of the package via a controlled tear produced by pulling one of its tongue ends, to obtain almost sealed seal closure folds (typically mini-portions of processed cheese).

• d'un bloc dur (e.g. un mini cube de bouillon) que l'on dépose dans l'enveloppe pour qu'elle l'enserre par une pression sans conséquence dommageable pour l'intégrité du bloc, ou
• d'une matière liquide ou pâteuse (e.g. une mini-portion de fromage fondu) sur laquelle on doit plier l'emballage, pour empêcher cette matière molle et instable de remonter tant dans les plis qu'à la surface d'ouverture de l'emballage, le scellage étant réalisé par la pression du fer à la température de dosage de cette matière (qui est typiquement supérieure à 65 ou 68° C).

To ensure the tight sealing of packages containing mini-portions, it is generally used a metal iron that is raised in temperature and which bears on the folds formed by reactivating the heat-sealing varnishes of the components of the package. By the exercise of this pressure and heating, seal the folds and surfaces of the packaging that are in contact under the iron and the mini-portion portion is squeezed, it being specified that the pressure exerted to achieve this sealing and this tamping gives the mini-portion its final shape. Usually two different ways, depending on whether the mini-portion is formed, at its dosing temperature in the package:

• a hard block (eg a mini cube of broth) that is deposited in the envelope so that it encloses it by a pressure without damaging consequences for the integrity of the block, or
• a liquid or pasty material (eg a mini-portion of processed cheese) on which the package must be folded, to prevent this soft and unstable material from rising in both the folds and the opening surface of the packaging, the sealing being carried out by the pressure of iron at the metering temperature of this material (which is typically greater than 65 or 68 ° C).

It is also known from the document WO-A-99/35057 packaging solid or pasty cheese portions, such as portions of melted cheese, in a metal envelope on which is sealed a metal seal, after filling the envelope previously folded into a predetermined shape by means of a device piston.

A major disadvantage of the known methods of sealing these packages for liquid or pasty mini-portions therefore lies in the need to perform the sealing at a temperature related to that of hot dosing of these mini-portions.

1. a) un formage de l'enveloppe à partir d'un flan ou ébauche de celle-ci pour lui conférer par pliage un fond et des parois latérales de formes prédéterminées délimitant une ouverture opposée au fond et présentant des portions repliées sur elles-mêmes, ces parois étant aptes à former des rabats supérieurs de l'enveloppe pour fermer partiellement cette ouverture,
2. b) une introduction par cette ouverture du produit dans l'enveloppe ainsi formée,
3. c) une application de l'opercule sur le produit de telle manière que l'opercule ferme sensiblement cette ouverture, lesdits rabats s'étendant alors à l'extérieur de l'opercule, et
4. d) un scellage à chaud de l'enveloppe sur l'opercule.

An object of the present invention is to provide a method of manufacturing sealed packages each containing a food product, in particular of the liquid or pasty type, which in particular makes it possible to remedy this drawback by sealing satisfactorily and independently of the temperature. dosing of the product, each package comprising an envelope receiving and laterally surrounding the product and a cap overlying the latter, the envelope and the cap being both based on metallic materials (for example aluminum), this process essentially comprising the following steps:

1. a) a forming of the envelope from a blank or blank thereof to give it by folding a bottom and side walls of shapes predetermined defining an opening opposite the bottom and having folded portions on themselves, these walls being able to form upper flaps of the envelope to partially close this opening,
2. b) an introduction through this opening of the product in the envelope thus formed,
3. c) an application of the lid to the product in such a way that the lid substantially closes this opening, said flaps then extending outside the lid, and
4. d) a heat seal of the envelope on the lid.

For this purpose, the method according to the invention is such that step d) is implemented by folding the flaps on the outer face of the lid, then sealing tightly under pressure these flaps on this outer face via an induction heating applied to the envelope, this sealing being obtained by hot activation of at least one adhesive provided at the sealing interface between the inner face of the envelope and the outer face of the lid.

It will be noted that with this method according to the invention, the sealing of the envelope and the lid used in step d) around a liquid or pasty product (ie soft and therefore deformable) is not due to the hot dosing temperature of this product, but to the induction heating subsequent to this dosage combined with the application under pressure of the flaps of the envelope on the lid. In other words, it is possible to seal the package containing the product independently of its dosing temperature, which may for example vary from 6 to 95 ° C for mini-portions of fresh cheese.

It will also be noted that this step d) of sealing according to the invention can advantageously be carried out in a very short time thanks to induction heating (fast start due to a lack of thermal inertia), with power densities and therefore a yield that can be very high. In addition, this induction heating guarantees the reproducibility of the sealing operations performed.

According to another characteristic of the invention, the sealing operation which follows the folding of the flaps on the lid is accompanied by a tamping of the underlying food product.

According to another characteristic of the invention, the envelope is coated on its inner face with a first heat-activatable adhesive, the lid being coated on its outer face with a second hot-activatable adhesive identical to the first adhesive or different of the last.

Advantageously, it is furthermore possible to seal in step d) said adjacent folded portions of the envelope, for example in the form of bellows, by pressing them on each other during this induction heating. by hot activation of said first adhesive.

Also advantageously, it is also possible to heat by induction said envelope blank in step a), to facilitate obtaining said folded portions and said flaps.

• a1) une mise au format souhaité d'un premier film souple métallique déroulé d'une première bobine, pour l'obtention de flans d'enveloppe de géométrie et de dimensions déterminées,
• a2) le formage de chaque enveloppe par pliage du flan correspondant dans une boîte de pliage au moyen d'un piston, puis
• a3) le transfert et la mise en place de chaque enveloppe ainsi formée dans le fond d'une alvéole surmontée d'un dispositif de chauffage par induction et de moyens de tassage et de scellage destinés à tasser ledit produit sous-jacent et à sceller sous pression lesdits rabats repliés sur l'opercule et lesdites portions repliées adjacentes sur elles-mêmes.

According to another characteristic of the invention, step a) can essentially comprise:

• a1) a desired format of a first metal flexible film unwound from a first coil, to obtain envelope blanks of geometry and determined dimensions,
• a2) forming each envelope by folding the corresponding blank in a folding box by means of a piston, then
• a3) the transfer and placement of each envelope thus formed in the bottom of a cell topped with an induction heating device and tamping and sealing means for tamping said underlying product and sealing under pressing said folded flaps on the cover and said folded portions adjacent to themselves.

Advantageously, step a) may further comprise, before step a2), a step of sealing on the inner face of each blank of at least one fusible opening strip of each package designed to open it by separation. on either side of a predetermined tearing direction via a gripping tab provided at the end of this strip, which has been previously cut to dimensions corresponding to those of each blank.

The or each opening strip of each package may be advantageously metallized and coated with a third heat-activatable adhesive which is identical to one and / or the other of said first and second adhesives, for the heat-sealing of this strip on the envelope.

As hot-activatable adhesive (s) that can be used on the envelope, the cover and on the or each heat-sealing strip of the package according to the invention, mention may for example be made of varnishes, commercially available hot melt glues and heat sealable heat sealable coatings.

According to another advantageous characteristic of the invention, step b) can comprise a cold dosage inside the envelope of said product, which is of liquid or pasty type, this dosage being advantageously carried out at a temperature below 30 ° C and for example between 8 and 12 ° C in the case of fresh cheese.

• c1) une mise au format souhaité d'un second film souple métallique déroulé d'une seconde bobine, pour l'obtention d'opercules de géométrie et de dimensions adaptées pour fermer sensiblement l'ouverture des enveloppes au contact du produit qu'elles contiennent, puis
• c2) un tassement de la surface supérieure du produit contenu dans l'enveloppe lors de la mise en place de chaque opercule, pour égaliser cette surface sous l'opercule.

According to another characteristic of the invention, step c) can essentially comprise:

• c1) a desired formatting of a second metal flexible film unwound from a second reel, for obtaining lids of geometry and dimensions adapted to substantially close the opening of the envelopes in contact with the product they contain then
• c2) a settlement of the upper surface of the product contained in the envelope during the introduction of each lid, to equalize this surface under the lid.

Advantageously, the induction heating can be performed in step d) immediately above each cell containing the envelope provided with the lid and, optionally, laterally on either side of this cell.

A sealed package according to the invention, which contains a food product in particular of the liquid or pasty type and which comprises an envelope receiving and laterally surrounding the product and a lid surmounting the latter, the envelope and the cover being both based on metal materials for example aluminum-based, is obtained by the manufacturing method according to the invention as defined above.

It will be noted that the packaging according to the invention is necessarily based on metallic materials, in order to be obtained by this process involving induction heating of this packaging.

This package according to the invention is such that the envelope comprises by folding a bottom and side walls delimiting an opening opposite to the bottom which is substantially closed by the lid, these side walls having adjacent portions folded on themselves and ending with flaps sealingly sealed to the outer face of the seal, at least one heat-activatable adhesive, such as heat-sealable varnish or hot melt glue, being provided at the sealing interface between the inner face of the seal envelope and this outer face of the lid and on the inner face of said folded portions to seal two by two these.

Advantageously, this packaging according to the invention may further comprise at least one heat-sealing strip for opening the package designed to open it by separation on either side of a predetermined direction via a gripping tab provided for end of this strip, which is heat sealed on the inner face of the envelope and is partly metallized.

The packaging according to the invention may advantageously contain a mini-portion of a dairy product, such as a fresh or melted cheese, for example, and this regardless of the process for preparing these mini-portions.

Note that the side walls of the envelope may be of substantially polygonal section (for example rectangular, square or triangular) or of rounded shape (for example circular), and that the grammage used may vary from 10 g to 500 g with dimensions of the envelope corresponding to the selected grammage.

• une première bobine destinée à acheminer un premier film apte à constituer lesdits flans d'enveloppe après mise au format adéquat de ce premier film,
• une unité de formage de ces enveloppes qui est agencée en aval de cette première bobine et qui comporte une pluralité de boîtes de pliage surmontées chacune d'un piston,
• une seconde bobine destinée à acheminer un second film apte à constituer lesdits opercules après mise au format de ce second film selon l'ouverture de chaque enveloppe,
• des moyens de transfert des enveloppes formées par l'unité de formage vers une unité de remplissage, d'operculage et de scellage des enveloppes respectivement pourvues de ces opercules,
• cette unité de remplissage, d'operculage et de scellage comportant une pluralité d'alvéoles qui sont chacune conçues pour recevoir l'enveloppe et qui sont surmontées d'un dispositif de chauffage par induction, de moyens de pliage pour replier lesdits rabats d'enveloppe sur l'opercule correspondant, et de moyens de tassage et de scellage pour tasser le produit sous-jacent et pour plaquer sous pression ces rabats ainsi repliés contre l'opercule, et
• un système de convoyeurs pour acheminer les films, les flans, les enveloppes et les emballages remplis, operculés et scellés.

An installation according to the invention for manufacturing packagings for implementing the method defined above essentially comprises:

• a first coil for conveying a first film capable of constituting said envelope blanks after formatting this first film,
• a forming unit of these envelopes which is arranged downstream of this first coil and which comprises a plurality of folding boxes each surmounted by a piston,
• a second coil for conveying a second film capable of constituting said lids after formatting of the second film according to the opening of each envelope,
• means for transferring the envelopes formed by the forming unit to a unit for filling, sealing and sealing the envelopes respectively provided with these covers,
• said filling, sealing and sealing unit having a plurality of cells each of which is adapted to receive the envelope and which is surmounted by an induction heating device, folding means for folding said envelope flaps on the corresponding lid, and tamping and sealing means for tamping the underlying product and for pressurizing said flaps thus folded against the lid, and
• a conveyor system for conveying filled, sealed and sealed films, blanks, envelopes and packages.

It will generally be noted that this installation may comprise means for transferring / conveying the various elements of the linear and / or rotary type.

• un ou plusieurs inducteurs de chauffage,
• une source de puissance moyenne ou haute fréquence associant un convertisseur de fréquence à un coffret d'adaptation d'impédance et de compensation,
• un système de refroidissement de la source de puissance, du coffret d'adaptation et éventuellement du ou des inducteurs,
• des moyens de présentation/ manutention des pièces à chauffer, et
• une unité de commande/ contrôle du dispositif de chauffage.

This induction heating device may advantageously comprise:

• one or more heating inductors,
• a medium or high frequency power source associating a frequency converter with an impedance matching and compensation box,
• a cooling system of the power source, of the adaptation box and possibly of the inductor (s),
• means for presenting / handling the parts to be heated, and
• a control / control unit of the heating device.

• la figure 1 est un schéma à blocs illustrant les principales étapes du procédé de fabrication d'emballages étanches selon l'invention et les principaux éléments de l'installation correspondante,
• la figure 2 est une vue schématique de dessus d'un flan d'enveloppe selon un premier exemple de réalisation de l'invention, pourvu d'une bandelette thermocollante d'ouverture de type double,
• la figure 3 est une vue schématique en perspective d'un emballage selon ce premier exemple de l'invention dont l'enveloppe a été formée par pliage puis scellage à chaud à partir du flan de la figure 2,
• la figure 4 est une vue schématique de dessus d'un flan d'enveloppe selon un second exemple de réalisation de l'invention, pourvu d'une bandelette thermocollante d'ouverture de type simple,
• la figure 5 est une vue schématique en perspective d'un emballage selon ce second exemple de l'invention dont l'enveloppe a été formée par pliage puis scellage à chaud à partir du flan de la figure 4,
• la figure 6 est une vue schématique de dessus d'un flan d'enveloppe selon un troisième exemple de réalisation de l'invention, pourvu d'une bandelette thermocollante d'ouverture de type double,
• la figure 7 est une vue schématique en perspective d'un emballage selon ce troisième exemple de l'invention dont l'enveloppe a été formée par pliage puis scellage à chaud à partir du flan de la figure 6,
• la figure 8 est une vue schématique en coupe transversale d'une bandelette thermocollante d'ouverture utilisable sur une enveloppe selon l'invention,
• la figure 9 est une vue schématique partiellement en coupe verticale d'une unité de remplissage, d'operculage et de scellage selon l'invention d'enveloppes pourvues d'opercules, cette unité comportant un dispositif de chauffage par induction de ces enveloppes,
• les figures 10 et 11 sont respectivement des vues en perspective d'un flan d'enveloppe selon le premier exemple de l'invention illustré à la figure 2 et de l'enveloppe formée par pliage de ce flan (illustrée à la même échelle que ce dernier), avant l'étape de scellage,
• la figure 12 est une vue en perspective éclatée montrant l'enveloppe de la figure 11 et l'opercule destiné à la surmonter en vue de l'étape de scellage,
• la figure 13 est une vue en perspective montrant un emballage selon l'invention finalement obtenu après mise en place et scellage de l'opercule sur l'enveloppe tels qu'illustrés à la figure 12, et
• la figure 14 est une vue en perspective montrant l'emballage de la figure 13 à l'état ouvert au moyen d'une traction exercée sur une bandelette thermocollante du type de celle illustrée à la figure 2.

Other characteristics, advantages and details of the present invention will emerge on reading the following description of several examples of embodiment of the invention, given for illustrative and not limiting, said description being made with reference to the accompanying drawings, among which :

• the figure 1 is a block diagram illustrating the main steps of the waterproof packaging manufacturing method according to the invention and the main elements of the corresponding installation,
• the figure 2 is a diagrammatic view from above of an envelope blank according to a first embodiment of the invention, provided with a fusible opening strip of the double type,
• the figure 3 is a schematic perspective view of a package according to this first example of the invention, the envelope of which has been formed by folding and then heat-sealing from the blank of the figure 2 ,
• the figure 4 is a schematic view from above of an envelope blank according to a second embodiment of the invention, provided with a heat-sealing opening strip of simple type,
• the figure 5 is a schematic perspective view of a package according to this second example of the invention, the envelope of which has been formed by folding and then heat-sealing from the blank of the figure 4 ,
• the figure 6 is a diagrammatic view from above of an envelope blank according to a third embodiment of the invention, provided with a fusible opening strip of the double type,
• the figure 7 is a schematic perspective view of a package according to this third example of the invention, the envelope of which has been formed by folding and heat-sealing from the blank of the figure 6 ,
• the figure 8 is a schematic cross-sectional view of a fusible opening strip for use on an envelope according to the invention,
• the figure 9 is a diagrammatic view partially in vertical section of a unit for filling, sealing and sealing according to the invention of envelopes provided with covers, this unit comprising a device for heating these casings by induction,
• the Figures 10 and 11 are respectively perspective views of an envelope blank according to the first example of the invention illustrated in FIG. figure 2 and the envelope formed by folding of this blank (illustrated at the same scale as the latter), before the sealing step,
• the figure 12 is an exploded perspective view showing the envelope of the figure 11 and the cap for overcoming it for the sealing step,
• the figure 13 is a perspective view showing a packaging according to the invention finally obtained after placing and sealing the lid on the envelope as illustrated in FIG. figure 12 , and
• the figure 14 is a perspective view showing the packaging of the figure 13 in the open state by means of a pull on a fusible strip of the type illustrated in FIG. figure 2 .

• une première bobine 10 destinée à acheminer le film 2 prévu pour constituer les flans d'enveloppe 4, 4a, 4b,
• des moyens de découpe 11 de bandelettes d'ouverture thermocollantes 9, 9a, 9b destinées à être en contact avec la face interne de chaque enveloppe 5, 5a, 5b (ces bandelettes sont visibles aux figures 2 à 7 en relation avec la figure 8 pour leur structure),
• des moyens de découpe 12 du film 2 pour former les flans d'enveloppe 4, 4a, 4b selon le format souhaité,
• des moyens de scellage à chaud 13 des bandelettes 9, 9a, 9b sur la face interne de chaque flan 4, 4a, 4b ou de l'enveloppe correspondante 5, 5a, 5b en résultant après pliage,
• une unité de formage 14 par pliage des enveloppes 5, 5a, 5b qui comporte une pluralité de boîtes de pliage (non illustrées) de chaque enveloppe 5, 5a, 5b surmontées chacune d'un piston,
• optionnellement (voir pointillés à la figure 1) des moyens de collage d'étiquettes 15 sur au moins une face externe de chaque enveloppe 5, 5a, 5b (étant précisé que l'on peut utiliser des films 2 pré-imprimés, évitant ainsi ce poste de collage supplémentaire),
• une unité de remplissage, d'operculage et de scellage 16 des enveloppes 5, 5a, 5b respectivement pourvues des opercules 6, 6a, 6b, cette unité 16 (visible à la figure 9) comportant une pluralité d'alvéoles 17 qui sont chacune conçues pour recevoir en leur fond 17a une enveloppe 5, 5a, 5b et qui sont surmontées d'un dispositif de chauffage par induction 18 et de moyens 19 de tassage et de scellage sous pression, sur l'opercule 6, 6a, 6b correspondant, de rabats supérieurs 5' de chaque enveloppe 5, 5a, 5b et des autres plis de celle-ci sur eux-mêmes (le fond 5" et les parois latérales 5"' d'enveloppe pourvues de ces rabats 5' sont visibles aux figures 11 à 13), ces rabats 5' étant préalablement repliés sur l'opercule 6, 6a, 6b et,
• une seconde bobine 20 destinée à acheminer le film 3 prévu pour constituer les opercules 6, 6a, 6b,
• des moyens de découpe 21 du film 3 suivant le format et les dimensions de l'ouverture supérieure de chaque enveloppe 5, 5a, 5b, agencés en amont de l'unité 16 en vue de la mise en place des opercules 6, 6a, 6b au contact des mini-portions 8 respectivement dosées dans les enveloppes 5, 5a, 5b, et
• des moyens de transfert et d'acheminement 22 des emballages scellés obtenus en sortie de l'installation 1.

As illustrated in figure 1 , an installation 1 according to the invention may comprise essentially, in addition to a conveyor system (not shown) arranged to convey the various casing films 2 and operculum 3 (both preferably based on aluminum), blanks d envelope 4, 4a, 4b (also called "formats" or "blanks", see Figures 2, 4 and 6 ), envelopes 5, 5a, 5b (see Figures 3, 5 and 7 ), caps 6, 6a, 6b (see figure 12 ) and packages 7, 7a, 7b sealed and sealed (see Figures 3, 5, 7 and 13 ), each package being filled with a mini-portion 8 of liquid or pasty consistency, such as a fresh cheese, for example (visible at the figure 14 ):

• a first coil 10 for conveying the film 2 provided to constitute the envelope blanks 4, 4a, 4b,
• cutting means 11 of heat-sealing opening strips 9, 9a, 9b intended to be in contact with the internal face of each envelope 5, 5a, 5b (these strips are visible at Figures 2 to 7 in relation to the figure 8 for their structure),
• cutting means 12 of the film 2 for forming the envelope blanks 4, 4a, 4b according to the desired format,
• heat sealing means 13 of the strips 9, 9a, 9b on the inner face of each blank 4, 4a, 4b or the corresponding envelope 5, 5a, 5b resulting after folding,
• a forming unit 14 by folding the envelopes 5, 5a, 5b which comprises a plurality of folding boxes (not shown) of each envelope 5, 5a, 5b each surmounted by a piston,
• optionally (see dotted line figure 1 ) label bonding means 15 on at least one outer face of each envelope 5, 5a, 5b (it being specified that it is possible to use pre-printed films 2, thus avoiding this additional gluing station),
• a unit for filling, sealing and sealing the envelopes 5, 5a, 5b respectively provided with the lids 6, 6a, 6b, this unit 16 (visible at the figure 9 ) having a plurality of cells 17 which are each adapted to receive at their bottom 17a a casing 5, 5a, 5b and which are surmounted by an induction heating device 18 and means 19 for compacting and sealing under pressure, on the lid 6, 6a, 6b corresponding, upper flaps 5 'of each envelope 5, 5a, 5b and other folds thereof on themselves (the bottom 5 "and the side walls 5"' d ' envelope provided with these flaps 5 'are visible to Figures 11 to 13 ), these flaps 5 'being previously folded on the lid 6, 6a, 6b and,
• a second coil 20 for conveying the film 3 intended to constitute the lids 6, 6a, 6b,
• cutting means 21 of the film 3 according to the format and the dimensions of the upper opening of each envelope 5, 5a, 5b, arranged upstream of the unit 16 in order to set up the covers 6, 6a, 6b in contact with the mini-portions 8 respectively dosed in the envelopes 5, 5a, 5b, and
• means for transferring and conveying sealed packages obtained at the outlet of the installation 1.

• des moyens de dosage (non illustrés) des mini-portions 8 (selon une large plage de température pouvant varier de 6 à 95° C dans le cas de fromages frais),
• des moyens de dépôt des opercules 6, 6a, 6b au contact des mini-portions 8 préalablement dosées dans les enveloppes 5, 5a, 5b,
• des moyens de pliage (non illustrés) des rabats 5' de chaque enveloppe 5, 5a, 5b sur la face externe d'un opercule 6, 6a, 6b ainsi déposé, ces moyens de pliage pouvant être constitués de plieurs ou de lames destinés à appuyer sur ces rabats 5' pour les replier sur cette face externe,
• le dispositif de chauffage par induction 18 qui comprend essentiellement :
  • * un ou des inducteurs de chauffage 22, prévus en retrait d'une distance d'environ 3 mm,
  • * une source de puissance moyenne ou haute fréquence associant un convertisseur de fréquence 23 de type générateur à transistor ou onduleur à un coffret d'adaptation d'impédance et de compensation 24 par batterie de condensateurs,
  • * un système de refroidissement par eau de la source de puissance 23, du coffret d'adaptation 24 et éventuellement du ou des inducteurs 22,
  • * des moyens de présentation/ manutention (non illustrés) des enveloppes 5, 5a, 5b à chauffer,
  • * des moyens de commande/ contrôle (non visibles) du dispositif 18, et
• les moyens 19 de tassage et de scellage attelés à un piston qui sont conçus à la fois pour tasser la mini-portion 8 sous l'opercule 6, 6a, 6b et pour sceller les rabats 5' de chaque enveloppe 5, 5a, 5b sur la face externe de l'opercule 6, 6a, 6b, via un fer de scellage équipant ce piston.

More specifically, the filling, sealing and sealing unit 16 comprises in particular:

• dosing means (not shown) of the mini-portions 8 (in a wide temperature range which can vary from 6 to 95 ° C in the case of fresh cheeses),
• means for depositing the lids 6, 6a, 6b in contact with the mini-portions 8 previously dosed in the envelopes 5, 5a, 5b,
• folding means (not shown) of the flaps 5 'of each envelope 5, 5a, 5b on the outer face of a lid 6, 6a, 6b thus deposited, these folding means being able to consist of folders or blades intended for press these flaps 5 'to fold them on this external face,
• the induction heating device 18 which essentially comprises:
  • one or more heating inductors 22, set back by a distance of approximately 3 mm,
  • a source of medium or high frequency power associating a frequency converter 23 of the transistor or inverter generator type to an impedance matching and capacitor compensation 24 box of capacitors,
  • a water cooling system of the power source 23, of the adaptation box 24 and possibly of the inductor (s) 22,
  • * means of presentation / handling (not shown) of the envelopes 5, 5a, 5b to be heated,
  • control / control means (not visible) of the device 18, and
• the means 19 for tamping and sealing coupled to a piston which are designed both to compact the mini-portion 8 under the cover 6, 6a, 6b and to seal the flaps 5 'of each envelope 5, 5a, 5b on the outer face of the lid 6, 6a, 6b, via a sealing iron equipping this piston.

• une couche interne 9A formée d'un vernis incolore thermoscellable,
• une fine couche de métallisation 9B en aluminium,
• une couche de polyester 9C en contact avec cette couche métallisée 9B,
• une couche de vernis incolore 9D par exemple en polyfluorure de vinylidène (PVDC), et
• une bande thermorésistante 9E en contact avec cette couche de vernis 9D et se terminant par une languette de préhension 9', pour ouvrir l'emballage 7, 7a, 7b par déchirure de l'enveloppe 5, 5a, 5b.

As illustrated in figure 8 the or each heat-sealing opening strip 9, 9a, 9b, for example of the Tircel® type (with a width for example of 2 to 3 mm and a thickness for example of the order of 40 μm), advantageously comprises its internal face intended to be in contact with the envelope 5, 5a, 5b at its external face:

• an inner layer 9A formed of a colorless heat-sealable varnish,
• a thin layer of aluminum metallization 9B,
• a polyester layer 9C in contact with this metallized layer 9B,
• a layer of clear 9D varnish, for example polyvinylidene fluoride (PVDC), and
• a heat-resistant band 9E in contact with this layer of lacquer 9D and ending with a gripping tab 9 ', to open the package 7, 7a, 7b by tearing the casing 5, 5a, 5b.

With reference to the figure 1 , the method of packaging the mini-portions 8 can be implemented as follows.

In a first step, the film 2 of the coil 1 is unwound, its inner face 2a upwards (intended to form the inner face of the envelope 5, 5a, 5b) so that it receives the strip or strips (s). ) 9, 9a, 9b. This inner face 2a is 100% or full-coated with a heat-activatable adhesive (for example at about 65 ° C.), such as a heat-sealing lacquer which is of course intended to be compatible with the foodstuffs and in addition with the hot-activatable adhesives 9A and 9D covering both sides of the opening strips 9, 9a, 9b and the covers 6, 6a, 6b.

The strip or each strip 9, 9a, 9b is cut beforehand by the cutting means 11, and is then deposited by heat-sealing it at a temperature of, for example, between 120 and 140 ° C. on the internal face 2a of the film 2. by ensuring that a strip end 9, 9a, 9b protrudes from the film 2 by forming a gripping tongue to allow the packaging 7, 7a, 7b to be opened by the consumer.

It is possible to make the choice of formatting envelope blank 4, 4a, 4b before or after this operation of laying and sealing the strips 9, 9a, 9b. Note that the other function of these strips 9, 9a, 9b is to direct the tear of the envelope to present the mini-portion completely free to consume. In the example of the figure 2 , the blank 4 has a substantially octagonal shape admitting two axes of symmetry X and Y perpendicular and the strip 9 is fork-shaped with two branches. In the example of the figure 4 , the blank 4a is substantially pentagonal, formed of an isosceles triangle whose base is extended by a rectangle, and the strip 9a is rectilinear along the median of greater length of this rectangle. In the example of the figure 6 , the blank 4b is substantially octagonal (admitting an axis of symmetry Z and with rounded corners), and it is coated with two strips 9b crossing on this axis.

Then, the forming unit 14 is used to fold each blank 4, 4a, 4b in a folding box provided for this purpose, each envelope 5, 5a, 5b thus formed being then placed in a cell 17 of the unit. filling, sealing and sealing 16 of these envelopes. As illustrated in Figures 11 and 12 , the casing 5 obtained includes portions P folded on themselves which are intended to be heat-sealed during the final step of sealing the casing 5 by induction.

The mini-portions 8 are then metered into the envelope 5, 5a, 5b housed in each cell 17, ie between 8 and 12 ° C., for example in the case of fresh cheese using a "cold" technology, or between 72 and 82 ° C for example according to a "hot" technology.

After dosing, the film 3 is unwound from the reel 20 in order to obtain the lids 6, 6a, 6b, the sealable face 3a of this film 3 (ie the outer face 3a of the lid) being oriented upwards. This face 3 is coated at 100% or full face with a hot-activatable adhesive 6 'at about 65 ° C., for example, such as a lacquer or clear lacquer (visible at figure 12 ) compatible with the food and with the adhesives of the envelope 5, 5a, 5b and those 9A, 9D of the strips 9, 9a, 9b. As an indication, this operculum film 3 may for example have a thickness of the order of ten microns, like the envelope film 2.

This film 3 is cut by means of the cutting means 21, so that the shape and the dimensions of each lid 6, 6a, 6b obtained correspond to those of the opening of the envelope 5, 5a, 5b corresponding, then each cap 6, 6a, 6b thus obtained is deposited on the mini-portion 8 by exerting sufficient pressure on the mini-portion 8 until the upper surface of the latter is equalized.

The following step consists in making the folding by tamping (for example under approximately 1 bar) of the upper flaps 5 'of each envelope 5, 5a, 5b (these flaps 5' are, for example, four in number for the envelope 5 according to the figures 3 and 13 ) on the outer face 3a of the lid 6, 6a, 6b corresponding.

Then the mini-portion 8 is compressed and the flaps 5 'are sealed on this outer face of the lid 3a by means of the aforementioned piston equipped with the sealing iron, via the induction heater concomitant with this packing and sealing. . As indicated above, this pressurization combined with this induction heating also makes it possible to seal the adjacent folded portions P of each envelope 5, 5a, 5b concerned one on the other.

It will be noted that, as an option, it is possible, after folding of the flaps 5 'on the lid 3a and before this packing-sealing, to pre-pack each mini-portion 8.

Thus, at the outlet of the installation 1, the mini-portions 8 respectively packaged in packages 7, 7a, 7b are sealed tightly, in a simple manner and in a very short time.

Claims (15)

1. Method of manufacturing sealed packets (7, 7a, 7b) each containing a food product (8), in particular of the liquid or paste type, each packet including an envelope (5, 5a, 5b) receiving and laterally surrounding the product and a film lid (6, 6a, 6b) on top of the latter, the envelope and the film lid both being metal-based, the method essentially comprising the following steps:

   a) forming the envelope from a blank (4, 4a, 4b) to confer on it by bending a bottom (5") and lateral walls (5"') delimiting an opening opposite the bottom and having portions (P) folded back on themselves, these walls being adapted to form upper flaps (5') of the envelope to close this opening partially,

   b) introducing the product into the envelope formed in this way via this opening,

   c) applying the film lid onto the product so that the film lid substantially closes this opening, said flaps then being outside the film lid, and

   d) heat-sealing the envelope to the film lid, characterised in that step d) is executed by folding the flaps over the external face of the film lid and then hermetically sealing these flaps under pressure onto this external face by induction heating applied to the envelope, this sealing being obtained by hot activation of at least one adhesive (6') provided at the sealing interface between the internal face of the envelope and the external face of the film lid.
2. Method according to claim 1 of manufacturing packets (7, 7a, 7b), characterised in that the sealing that follows folding said flaps (5') is accompanied by compacting said underlying product (8).
3. Method according to claim 1 or claim 2 of manufacturing packets (7, 7a, 7b), characterised in that the envelope (5, 5a, 5b) is coated on its internal face (2a) with a first heat-activated adhesive, the film lid (6, 6a, 6b) being coated on its external face (3a) with a second heat-activated adhesive (6') identical to or different from the first adhesive.
4. Method according to claim 3 of manufacturing packets (7, 7a, 7b), characterised in that in step d) said adjacent folded portions (P) of the envelope (5, 5a, 5b), in the form of bellows, for example, are sealed on pressing them one onto the other during this induction heating by heat activation of said first adhesive.
5. Method according to any one of the preceding claims of manufacturing packets (7, 7a, 7b), characterised in that said envelope blank (4, 4a, 4b) is also induction heated in step a) to facilitate obtaining said folded portions (P) and said flaps (5').
6. Method according to any one of the preceding claims of manufacturing packets (7, 7a, 7b), characterised in that step a) essentially comprises:

   a1) forming as required a first flexible metal film (2) paid out from a first spool (10) to obtain envelope blanks (4, 4a, 4b) of particular geometry and dimensions,

   a2) forming each envelope (5, 5a, 5b) by folding the corresponding blank in a folding box by means of a piston, and then

   a3) transferring and placing each envelope formed in this way in the bottom (17a) of a cell (17) surmounted by an induction heating device (18) and compacting and sealing means (19) adapted to compact said underlying product (8) and to seal under pressure said flaps (5') folded over the film lid (6, 6a, 6b) and said adjacent folded portions (P) on themselves.
7. Method according to claim 6 of manufacturing packets (7, 7a, 7b), characterised in that step a) further comprises, before step a2), a step of sealing to the internal face of each blank (4a, 4a, 4b) at least one heat-adhesive strip (9, 9a, 9b) for opening each packet by separation on either side of a predetermined tearing direction via a grasping tongue (9') provided at the end of said strip, which has been previously cut to dimensions corresponding to those of each blank.
8. Method according to claims 3 and 7 of manufacturing packets (7, 7a, 7b), characterised in that said or each strip (9, 9a, 9b) for opening each packet is metallised and coated with a third heat-activated adhesive (9A, 9D) that is identical to said first adhesive and/or said second adhesive for hot sealing this strip to the envelope (5, 5a, 5b).
9. Method according to any one of the preceding claims of manufacturing packets (7, 7a, 7b), characterised in that step b) comprises cold dosing inside the envelope (5, 5a, 5b) a measured quantity of said product (8), which is of liquid or paste type, this dosing being advantageously carried out at a temperature below 30°C and for example in the range 8°C to 12°C in the case of fresh cheese.
10. Method according to any one of the preceding claims of manufacturing packets (7, 7a, 7b), characterised in that step c) essentially comprises:

    c1) forming as required a second flexible metal film (3) paid out from a second spool (20) to obtain film lids (6, 6a, 6b) of geometry and dimensions adapted substantially to close the opening of the envelopes (5, 5a, 5b) in contact with the product (8) that they contain, and then

    c2) compacting the upper surface of the product contained in the envelope when placing each film lid to equalise this surface under the film lid.
11. Method according to any one of claim 6 to 8 of manufacturing packets (7, 7a, 7b), characterised in that the induction heating is effected in step d) immediately above each cell (17) containing the envelope (5, 5a, 5b) provided with the film lid (6, 6a, 6b) and, optionally, laterally on either side of this cell.
12. Sealed packet (7, 7a, 7b) containing a food product (8) of liquid or paste type, the packet including an envelope (5, 5a, 5b) receiving and laterally surrounding the product and a film lid (6, 6a, 6b) on top of the latter, the envelope and the film lid both being metal-based, for example aluminium-based, the packet being obtained by a method according to any one of the preceding claims, characterised in that the envelope includes as a result of folding it a bottom (5") and lateral walls (5"') delimiting an opening opposite the bottom that is substantially closed by the film lid, these lateral walls having adjacent portions (P) folded back on themselves and ending in flaps (5') hermetically sealed to the external face (3a) of the film lid, at least one heat-activated adhesive (6'), such as heat-seal varnish or hot-melt glue, being provided at the sealing interface between the internal face (2a) of the envelope and this external face of the film lid and on the internal face of said folded portions to seal the latter two by two.
13. Sealed packet (7, 7a, 7b) according to claim 12, characterised in that it further includes at least one heat-adhesive strip (9, 9a, 9b) for opening the packet by separation on either side of a predetermined tearing direction via a grasping tongue (9') provided at the end of said strip, which is heat-sealed to the internal face (2a) of the envelope (5, 5a, 5b) and is partially metallised.
14. Sealed packet (7, 7a, 7b) according to claim 12 or claim 13, characterised in that the product (8) that it contains consists of a mini-portion of a dairy product such as a fresh cheese or a process cheese.
15. Installation (1) for manufacturing packets (7, 7a, 7b) adapted to use a method according to any one of claims 1 to 11, characterised in that it essentially includes:

    - a first spool (10) adapted to pay out a first film (2) adapted to constitute said envelope blanks (4, 4a, 4b) after appropriate forming of this first film,

    - a unit (14) for forming the envelopes (5, 5a, 5b) that is arranged downstream of this first spool and includes a plurality of folding boxes each surmounted by a piston,

    - a second spool (20) adapted to pay out a second film (3) adapted to constitute said film lids (6, 6a, 6b) after forming this second film according to the opening of each envelope,

    - means for transferring the envelopes formed by the forming unit to a unit (16) for filling, applying the film lid to and sealing envelopes provided with these film lids,

    - this filling, film lid application and sealing unit (16) including a plurality of cells (17) each designed to receive the envelope and surmounted by an induction heating device (18), folding means for folding the envelope flaps (5') over the corresponding film lid and compacting and sealing and compacting means (19) for compacting the underlying product (8) and pressing these flaps folded in this way against the film lid under pressure, and

    - a system of conveyors for the films, blanks, envelopes and packets that have been filled, had the film lid applied and sealed.

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