EP2166885A1

EP2166885A1 - Line and process for the heat treatment of products contained in bags, with sealing of the latter

Info

Publication number: EP2166885A1
Application number: EP07788957A
Authority: EP
Inventors: Alain Germain; Mostafa El Haba
Original assignee: Mes Technologies; MES Technologies SAS
Current assignee: Mes Technologies; MES Technologies SAS
Priority date: 2007-06-04
Filing date: 2007-06-04
Publication date: 2010-03-31
Also published as: WO2008148945A1

Abstract

The invention relates to the heat treatment of a consumable product contained in a pouch (10). The product is introduced into a pouch, which is then partially sealed, maintaining an initially unsealed zone forming a vent, and then moved along to a heating station, which pouch is, after heating, completely closed. While moving the pouch along, the latter is held in place such that the initially unsealed zone occupies, as the pouch passes through a sealing station, a given position relative to a sealing tool (120) present in this station, and additional sealing of the zone is performed when the latter occupies the given position.

Description

Line and method for heat treatment of products contained in pouches, with sealing of the latter

The present invention relates to the heat treatment of a consumable product contained in a pocket.

More specifically, the invention relates to a method of heat treatment of a consumable product contained in a bag, wherein, after introduction of the product into a bag, it is partially sealed by preserving an initially unsealed area forming a vent, This bag is fed to a heating station and, after heating, the bag is closed completely.

The heat treatment (heating), for example by microwaves, of the product serves in particular to promote its preservation. It can be a simple cooking, complete or partial, or a pasteurization or sterilization. The heating is done in a heating station.

It is recalled that pasteurization can destroy some bacteria by heating. During pasteurization, it is sought to avoid, at least to limit, the alteration of the physicochemical properties of the consumable product. For example, during a pasteurization, this product can be brought to a temperature of 80 ⁰ C to 100 ⁰ C, for a given time, for example of the order of 3 to 5 min, so as to ensure a date consumption limit of 20 days after this treatment.

By carrying out a sterilization, it is possible to postpone this expiry date to a much longer period, for example of the order of one year, by bringing the product to a higher temperature, for example of the order of 120 ^° C. during the necessary duration, for example of the order of 3 to 5 min.

The consumable product is in particular a food product, such as vegetables, fruits or other fresh, blanched or precooked foods, or frozen foods. It can also be cooked dishes, for example by taking meat or fish, or any food preparation.

The pocket is advantageously made of plastic or composite, allowing heating by microwaves. At the end of the process, the packaged product can be stored for some time. Depending on the case, it may, at the opening of the bag, be consumed as a fresh product or as a cooked or precooked product. It can be warmed up before consumption, without necessarily being previously extracted from the pocket. When heating the product contained in the bag, there is a release of steam, which puts the inside of the packaging under overpressure. To prevent this overpressure leading to a bursting of the pocket, the French patent application FR 2 852 921 recommends that only partially close the pocket before heating, leaving an initially unsealed area (chimney), through which the steam overpressure in the pocket can escape and seal the initially unsealed area by a welding operation performed at the end of heating.

Ideally, the seal of the bag should take place shortly after the end of heating to keep some of the steam in the pocket. This sealing being difficult to achieve in the heating station or just at its exit, it is necessary to transfer the bag to a sealing station, where will be carried out a complementary sealing of the initially unsealed area. In order to achieve this additional seal in an industrially viable manner, it is necessary that the pocket is correctly positioned at the time of the complementary seal, so that the latter can precisely affect the initially unsealed area.

However, during the heat treatment and the training of the pocket, the latter may have a tendency to move. In particular, during and immediately after the passage of the pocket in the heating station, the swelling of the pocket caused by the steam under pressure causes movement of the pocket. The initially unsealed area therefore moves unpredictably, and is no longer in a position to be sealed in the sealing station when it succeeds.

The present invention aims to overcome these disadvantages by providing a method that allows, in a simple and reliable way, to correctly position the bag to achieve the desired additional seal. This object is achieved by the fact that by driving the bag, the latter is held so that the initially unsealed area occupies, during the passage in a sealing station, a predetermined position relative to a sealing tool present in this position, and is carried out a complementary sealing of the zone when the latter occupies the determined position.

Thanks to these provisions, the sealing of the initially unsealed area can be performed automatically and reproducibly, for example on a production line. Moreover, a manual intervention to keep the pocket in position for sealing the chimney in the sealing station is not necessary, which reduces production costs.

Advantageously, after heating, a closure member is applied to the initially unsealed zone, a complementary sealing is performed while the member is applied, and then the closure member is stopped.

The use of a closure member between the outlet of the heating station and the sealing station avoids contamination of the bag by the ambient air. Indeed, as soon as the heating ends, the temperature in the pocket decreases. The pressure in the pocket relative to the outside atmosphere then decreases to equilibrium, thus risking allowing the ambient air to be sucked into the pocket by the chimney, which can lead to contamination of the pocket. and cancel the pasteurization operation, and is therefore undesirable. Typically, the closing of the chimney by the shutter member must not take place more than a few seconds after the end of heating.

Advantageously, to completely close the bag, is successively made in the initially unsealed area a complementary seal and a final seal. The final seal, a separate operation of the additional seal, provides additional security for the hermetic closure of the bag.

Advantageously, the sealing member is no longer applied between the complementary seal and the final seal. Once the additional sealing of the initially unsealed area (chimney) is achieved, it is no longer necessary to maintain the shutter member applied thereto. In addition, by removing the shutter member, the chimney is released to allow the final sealing tool to perform the final sealing of the chimney.

The invention also relates to an installation for heat treatment of a consumable product contained in a bag, comprising means for driving a bag, which contains a product and which has a partial seal preserving an initially unsealed area forming a vent , a heating station and a complementary sealing station, disposed downstream of the heating station in the driving direction and comprising a complementary sealing tool adapted to perform a complementary sealing of said zone to close the pocket completely.

The invention aims to propose an installation that overcomes the aforementioned drawbacks in relation with the prior art mentioned above, by making it possible to carry out the complementary sealing on the correctly positioned pocket in a simple and reliable manner.

For this purpose, according to the invention, the installation comprises a holding mechanism for maintaining the pocket relative to the drive means so that, in the sealing station, the initially unsealed zone occupies a position determined by relative to the sealing tool to allow additional sealing.

Advantageously, said holding mechanism is able to hold said bag from the upstream of the heating station in the driving direction downstream of the complementary sealing station, and to release the bag downstream of this complementary sealing station. .

Maintaining the bag upstream of the heating station, that is to say before heating the product contained in the bag, makes it possible to ensure that the initially unsealed area of the bag is maintained at a fixed position relative to the drive means, and throughout the passage of the pocket in the heating station. The initially unsealed area, being further maintained at this fixed position downstream of the sealing station, will therefore always arrive in a suitable position to be sealed properly in the sealing station by a sealing tool when it is driven. in the sealing station by the drive means. Advantageously, the holding mechanism comprises studs intended to cooperate with holes drilled in the sealed portion of the pocket on each side of said initially unsealed zone, and means opposing the clearance of the holes relative to the studs. This configuration of the holding mechanism allows a simple and effective maintenance of the pocket: it is sufficient to first drill holes in the sealed portion of the pocket, for example a hole on each side of the chimney (initially unsealed area), then to put these holes on the nipples. The pocket chimney is thus maintained at a fixed position in a horizontal plane relative to the drive means. Additional means then prevent the bag from disengaging the nipples.

For example, these additional means are formed by a strip which extends, in the path of the pocket, above the sealed portion, in the vicinity of the nipples.

Advantageously, the installation further comprises a temporary closure mechanism able to temporarily close the initially unsealed area at the outlet of the heating station, the mechanism being in the closed position when it closes the zone, and in the open position when he does not close it.

In other words, the shutter member is activated near the outlet of the heating station and upstream of the sealing station. It makes it possible to easily close the bag downstream of the heating station, and in particular, to do it before its internal pressure equilibrates with the atmospheric pressure which, as indicated previously, could lead to contamination of the contents. from the pocket.

Advantageously, the temporary closure mechanism is integral with the holding mechanism.

This fastening makes it possible to simply produce, in a single follower block, the mechanisms for holding and temporarily closing a pocket. The materials constituting these mechanisms are compatible with the heating means, for example microwaves.

Advantageously, the temporary closure mechanism comprises a closure member intended to pinch the initially unsealed area so as to prevent any fluid from passing between the inside and the outside of the pocket, the mechanism then being in position closed, and a lever rotatable about an axis, the shutter member being located on the lever.

Advantageously, the installation comprises a closure system adapted to bring the shutter mechanism from the open position to the closed position, and an opening system adapted to bring the shutter mechanism from the closed position to the open position.

Advantageously, the complementary sealing tool comprises a heat sealing head intended to effect the complementary sealing of the initially unsealed zone by coming into contact with this zone between the place where this zone is closed by the temporary sealing mechanism and where this area opens into the inside of the pocket.

While the initially unsealed area is closed by the temporary closure mechanism, for example by being pinched by the closure member, the portion of the initially unsealed area between the place where this area is closed by the temporary closure mechanism and the place where this area opens into the interior of the pocket is clear and therefore accessible to a heat sealing head coming into contact with this area to seal it.

Advantageously, the installation further comprises a final sealing station disposed downstream of the complementary sealing station in the driving direction and comprising a final sealing tool capable of final sealing the initially unsealed area. For example, the final sealing tool comprises a heat sealing head for final sealing of the initially unsealed area coming into contact with this area.

This final seal increases the area of the seal, and thus enhances the safety of closing the initially unsealed area.

Advantageously, the installation comprises a bag release system for releasing this pocket from the holding mechanism downstream of the sealing station.

For example, the bag release system is able to slide the aforementioned pins out of the holes so as to release the pockets of the holding mechanism downstream of the sealing station. The bag is released from the holding mechanism downstream of the complementary sealing station, or, where appropriate, downstream of the final sealing station. Once the bag no longer undergoes sealing operation, precise positioning of the initially unsealed area is no longer necessary. The release system allows the pocket to continue its journey on the production line to possibly downstream stations.

The invention will be better understood and its advantages will appear better on reading the detailed description which follows, of an embodiment shown by way of non-limiting example. The description refers to the accompanying drawings in which:

FIG. 1 schematically illustrates an installation according to the invention,

FIG. 2 is a perspective view showing the positioning of the pocket on the holding mechanism,

FIG. 3 is a cross-sectional view of the installation showing the pocket during its heating, taken along line III-III of FIG. 1;

FIG. 4 is a cross-sectional view of the installation, showing the application of the closure member taken along the line;

IV-IV of Figure 1,

FIG. 5 is an exploded perspective view of the shutter mechanism,

FIG. 6 is a perspective view of the closure cam of the shutter mechanism,

FIG. 7 is a sectional view of the closure mechanism and of the holding device at the complementary sealing station, showing the application of the sealing tool, taken along the line VII-VII of FIG. 1, FIG. 8 illustrates the opening of the shutter mechanism by an opening cam,

FIG. 9 is a perspective view of the opening cam,

- Figure 10 is a sectional view of the closure mechanism and the holding device at the final sealing station, showing the application of the sealing tool, taken along the line

XX of Figure 1 - Figure 11 is a perspective view illustrating the bag release system.

FIG. 1 shows an installation in which the various stages of the heat treatment process of the invention are carried out. In step 1 the bag 10 is placed on the drive means such as a treadmill 30 or the like, and positioned on the holding mechanism 40. This pocket 10, which may have any shape, is shown on the figures with a rectangular shape. The bag 10 has previously been filled with a consumable product. As shown in FIG. 2, the bag 10 is, after filling, sealed so that communication between the inside 12 and the outside of the bag is possible by an initially unsealed zone 14 on one of the sealed zones 16 from the pocket. The sealed area has the appearance of a band on one edge of the pocket 10, and the initially unsealed area 14 forms a conduit or chimney passing through the sealed area 16 of the inside 12 of the pocket towards the outside of the pocket. the pocket. The sealed zone 16 comprising the chimney 14 is pierced with two holes 21, 22. Each hole passes right through this sealed zone 16 in the direction of its thickness, and the chimney 14 is located between the two holes 21, 22. In Figure 1 and the following figures, the holding mechanism 40 comprises a block 50 which is fixed on the belt 30, and two pins 51, 52 which protrude from the upper face 54 of the block 50. The plane passing through the two axes of the two pins 51, 52 is perpendicular to the belt 30 and extends in the driving direction of the belt 30. The two pins 51, 52 are represented as cylinders with constant circular section, perpendicular to the upper face 54, and with hemispherical upper extremities. These pins 51, 52 could however take any other form allowing them to slip into the holes 21, 22, and be easily removed from the holes 21, 22, such as for example to be square or hexagonal, have a conical end or pyramidal. The nipples 51, 52 may also be inclined relative to the perpendicular to the upper face 54 in the direction of the pocket 10, this to facilitate their insertion into the holes 21, 22, and their withdrawal from them. The pocket is thus positioned on the holding mechanism by threading the two pins 51, 52 in the two holes 21, 22. The chimney 14 is thus between the two pins 51, 52. Once positioned, the sealed zone 16 and the straight line connecting the two holes 21, 22 extend substantially in the driving direction of the belt 30, and the chimney 14 extends substantially in a direction perpendicular to the driving direction of the belt 30. Alternatively, instead of nipples, the holding mechanism

40 may comprise two clamps 401, 402, shown in dashed lines in Figure 2. A first clamp 401 is intended to pinch the sealed portion 16 of the pocket 10 on one side of the chimney 14, the second clamp 402 is intended for pinch the sealed portion 16 on the other side of the chimney 14 so that the chimney is between the first gripper 401 and the second gripper 402, the latter thus holding the pocket 10 integral with the holding mechanism 40. These grippers are brought and maintained in the pinching position of the pocket by a device (not shown) such as, for example, screws, springs. They can be opened and closed automatically by a mechanism similar to that which opens and closes the temporary shutter mechanism described below.

In FIG. 1 to step 2, the bag 10 is transferred by the belt 30 and the holding mechanism 40 to the heating station, in which step 3, which is the heating, is carried out. From the step 2 included, amounts 62 are arranged at intervals along the belt 30, being straightened relative thereto. These amounts 62 are hooked by one of their ends, the lower end 64, on a support 65 running along the edge of the belt 30, and are fixed relative to the support of the belt 30, that is to say that the carpet 30 moves relative to them.

As illustrated in Figures 3 and 4, the uprights 62 are shaped in brackets and have head ends 66, which overlie the pockets, near the sealed areas 16. The heads 66 of the brackets carry a strip 70. The strip 70 s extends horizontally in its greatest direction in the driving direction of the belt 30 and above the edge thereof. A device 68 consisting of a screw / nut system cooperating with oblong holes in the slider 70 and in the head 66, or a similar device, allows the level of each upright 62 to expand the slider 70 in the driving direction. carpet at the heating station. The fastening system of the lower end 64 of the upright 62 allows a vertical displacement of the upright 62 and thus the vertical adjustment of the slide 70. The lower end 72 of the slide 70 is located above the sealed zone 16 of the pocket 10, and below the horizontal plane in which are located the upper ends of the pins 51, 52. In addition, the lower end 72 is beyond the pins 51, 52 relative to the edge of the pocket 10. In this way, if the pocket 10 moves upwards such so that the sealed zone 16 slides towards the upper ends of the pins 51, 52, the portion of the sealed zone 16 located between the pins 51, 52 and the portion of the bag 10 containing the consumable product abuts against the lower end 72 of the slider 70, thus preventing the pins 51, 52 out of the holes 21, 22, and therefore preventing the chimney 14 from coming out between the two pins 51, 52. The chimney 14 thus remains positioned so that, during his pass Later in the sealing station, it occupies a determined horizontal position relative to the sealing tool.

In Figure 1 to step 3, the pocket 10, the sealed zone 16 has its holes 21, 22 threaded on the pins 51, 52 and is thus maintained by the strip 70 passes into the heating station. In the heating station, the consumable product located inside the pocket 10 is heated, for example by the application of microwaves. By this heating, there is produced in the pocket 10 a release of air and steam, which puts the inside 12 in excess pressure, and causes swelling of the pocket 10, as shown in Figure 3.

At the outlet of the heating station, the pocket 10, whose sealed zone 16 still has its holes 21, 22 held on the nipples 51, 52 by the slide 70, deflates, since the overpressure is no longer maintained by heating . The air and the steam escape from the interior 12 of the pocket 10 through the chimney 14, which thus acts as a vent. Thus the pressure in the pocket 10 decreases until equilibrium with the atmospheric pressure prevailing outside the pocket 10. In order to prevent the ambient air from being sucked into the pocket 10 through the chimney 14, which could lead to the contamination of the bag 10 and cancel the pasteurization operation by heating, the stack 14 of the bag 10 is closed by a temporary shutter mechanism 80 following the heating station. More specifically, the position of the closure means is such that the shutter is produced while the pressure in the pocket 10 is still slightly higher than the atmospheric pressure, to avoid any incoming gas flow. This shutter operation constitutes step 4 of FIG.

As illustrated in FIGS. 3, 4, and 5, the temporary closure mechanism 80 comprises a lever 82 that is free to pivot about a horizontal rod 81, and comprises a lever support 90. The rod 81 is cylindrical and is extends horizontally in the driving direction of the belt 30. The lever 82 comprises a front arm 84 and a rear arm 85, which meet substantially at right angles, so that the lever 82 has the shape of a vertex L 86 .

In the sense of the present description, along a horizontal axis perpendicular to the driving direction of the belt 30, the forward direction is defined as going from the edge of the pocket 10 having the initially unsealed zone towards the opposite edge, and the direction back is the opposite.

The front arm 84 is pierced with a hole slightly offset from the top 86, through which the rod 81 passes. The rod 81 is supported at its two ends by two branches, a first branch 91 and a first branch 92, which form a fork flanking the lever 82. The branches 91, 92 are substantially vertical and are extensions of the lever support 90. The latter is integral with the block 50, which itself is fixed to the belt 30 by two screws 58. The lever support 90 may also be directly attached to the belt 30. The first leg 91 and the second leg 92 are each pierced by a hole in which the rod 81 passes, which is thus supported by these two branches so that the lever 82, located between these two branches, can pivot about the rod 81. At the end of the front arm 84, a closure member 88 is fixed by means of a fastener 89. The temporary closure mechanism 80 also comprises two elastics 96a, 96b. Each of the elastics 96a, 96b has a rest form a ring, and is maintained in extension by two pads 97, 98 which have the shape of cylindrical rods. The arm pin 97 protrudes from the front arm 84 with which it is secured, and extends horizontally on both sides of the front arm 84 in the driving direction of the belt 30. The support pad 98 protrudes from the lever support 90 with which it is secured, and extends horizontally on both sides of the lever support 90 in the driving direction of the belt 30. The support pad 98, which is fixed relative to the rod 81, is located below the rod 81, and slightly closer to the vertical plane passing through the pins 51, 52. The first elastic 96a is passed around the portion the arm stud 97 protruding from the front arm 84 on the side of the first arm 91, and around the portion of the support pad 98 protruding from the lever bracket 90 on the side of the first arm 91, so that the first arm 91 is located between the first elastic 96a and the lever 82. The second elastic 96b is passed around the portion of the arm stud 97 which protrudes from the front arm 84 on the side of the second arm 92, and around the portion of the support pad 98 which protrudes from the lever support 90 on the side of the second arm 92 so that the second arm 92 is located between the second elastic 96b and the lever 82. The first elastic 96a and the second elastic 96b are each held in extension by the stud of arm 97 and the stud The elastic bands 96a, 96b could also be springs, or any other resilient means capable of exerting a restoring force.

The role of the elastics 96a, 96b is explained below. The temporary closure mechanism 80 has two stable positions: an open position where the temporary closure mechanism 80 does not close the chimney 14, and a closed position where this mechanism closes the chimney 14.

Figure 3 shows the temporary closure mechanism 80 in the open position. The lever 82 has its front arm 84 substantially vertical, inclined in the opposite direction to that where the block 50 and the pocket 10, that is to say towards the rear, and its rear arm 85 substantially horizontal, inclined down. The arm stud 97, the support pad 98, and the rod 81 are arranged such that, in the open position, the rod 81 is located above the elastics 96a, 96b which connect the arm stud 97 and the stud In order for this arrangement to be possible, the arm stud 97 is located on a protrusion 99 of the front arm 84 which protrudes from this arm in the direction opposite to that in which the block 50 and the pocket 10 are located. that is, rearward, substantially parallel to the rear arm 85. Thus, the restoring force exerted by the elastics 96a, 96b in extension holds the lever 82 in the open position. In the open position, the top 86 of the closure mechanism abuts on the ramp of the lever support 90 located between the arms 91, 92, and is held in this position by the elastics 96a, 96b, as illustrated in FIG.

Figure 4 shows the temporary closure mechanism 80 in the closed position. The lever 82 has its front arm 84 substantially horizontal, directed towards the block 50 and the pocket 10, that is to say towards the front, and its rear arm 85 substantially vertical, directed upwards. In this position, the closure member 88, which has the shape of a trapezoidal parallelepiped tapering downwards, and whose largest dimension extends in the driving direction of the belt 30, presses on the chimney 14 and wedge against the upper face 54 of the block 50. Thus, the chimney 14 is pinched and air can circulate between the inside and the outside of the pocket 10. Preferably the shutter member 88 is made of flexible material to catch any play in the shutter mechanism 80 and ensure a nip of the stack 14. The elastics 96a, 96b which connect the arm pin 97 and the support pad 98 are then between the block 50 and the rod 81, and thus exert a restoring force which keeps the closure member 88 pressed against the chimney 14. The elastics 96a, 96b thus maintain the temporary closure mechanism 80 in the closed position. The closing member 88 may have a shape different from that of a trapezoidal parallelepiped, for example having a convex lower face, as long as when it is gripping the chimney 14, the air can not pass through it. this. For example, the closure member 88 could be an O-ring placed in a groove dug around the fastener 89, this fastener having substantially the shape of a parallelepiped whose largest dimension extends in the direction of When the temporary closure mechanism 80 is in the closed position, the O-ring placed in the groove surrounds a horizontal axis perpendicular to the driving direction of the belt 30, and the lower edge of the O-ring comes to bear. on the stack 14 so as to clamp it against the upper face 54 of the block 50.

The passage of the temporary shutter mechanism 80 from the open position to the closed position is via a closure system. The closure system includes a closure cam 100, which is attached to the support 65, i.e. the belt 30 moves relative thereto. This closing cam is illustrated in FIG. 6, in FIG. 4, and in FIG. 1, where it is located at the beginning of Step 4. The closing cam 100 has the shape of a ramp whose top surface 102, initially horizontal, inclines gradually in the driving direction of the belt 30, so that the ramp is becoming higher. Thus, when the temporary closure mechanism 80 moves with the belt 30, the rear arm 85 of the lever 82 comes into contact with the closing cam 100, and is gradually pushed upwards by the latter. The closure cam 100 has a horizontal cam guide 104 located on the front face of the closing cam 100 and which is intended to cooperate with a horizontal notch 93 on the rear face of the lever support 90. This cooperation makes it possible to position the closing cam 100 correctly relative to the temporary closure mechanism 80. The end 106 of the cam guide 104 directed in the direction opposite to the driving direction of the belt 30 is beveled to ensure its start of sliding in the notch 93. When the rear arm 85 of the lever 82 is gradually pushed upwards by the closing cam 100, the lever 82 pivots about the axis 81 in the counterclockwise direction in FIG. indicated by the arrow F. This rotation of the lever 82 is initially against the restoring force of the elastics 96a and 96b, because the restoring force exerted by the elastics 96a, 96b in extension produces a moment by r supply to the axis of rotation of the rod 81 which tends to rotate the lever 82 in the direction of clockwise, that is to say in the opposite direction of the arrow F. Then, when the rotation of the lever 82 has passed the point of rotation where the arm pin 97 is aligned with the support pad 98 and the rod 81 so that the elastics 96a, 96b which connect the arm pin 97 and the support pad 98 is located between the block 50 and the rod 81, the elastics 96a, 96b exert a restoring force which produces a moment relative to the axis of rotation of the rod 81 which tends to pivot the lever 82 in the direction of the arrow F, that is to say the opposite direction of the clockwise. The elastic bands 96a, 96b then come to press the closure member 88 against the chimney 14 which is pinched between the closure member 88 and the upper face 54 of the block 50, and hold the closure member 88 in position. this position. Thus, the interaction of the rear arm 85 with the closure cam 100 allows the temporary closure mechanism 80 to automatically switch from the open position to the closed position as the pocket 10 moves in the installation in the driving direction, driven by the holding mechanism 40.

Alternatively, instead of elastics, the temporary closure mechanism 80 may comprise two links hinged together at one end about an axis, the other end of the first link being connected to the block 50 by a pivot connection around the axis 98, the other end of the second link being connected to the lever 82 by a pivot connection about the axis 97, so that when the first link pivots about the axis 98, the lever 82 pivots around of the axis 81 between its open position and its closed position.

Once the temporary shutter mechanism 80 in the closed position, the strip 70 is no longer necessary because the sealed edge 16 of the bag 10 is now held on the pads 51, 52 by the lever 82. In addition, the strip 70 and its support 62 could interfere with the subsequent sealing operation of the chimney 14 if they are in the path of the complementary sealing tool. The strip 70 and its support 62 therefore do not extend along the belt 30 beyond step 4, as illustrated in FIG.

In FIG. 1 to step 5, the pocket 10 passes into the sealing station so that its stack 14 is sealed by a complementary sealing tool 120. The complementary sealing tool 120 is mounted on a device, not shown, located in height relative to the belt 30 and which moves parallel to the latter in a manner synchronized with the movement of the holding mechanism 40 and the pocket 10, so that during all the time when the pocket 10 moves in the post sealing, the complementary sealing tool 120 is permanently positioned above the chimney 14, without touching it except at the time of sealing. In this case, the sealing tool can move back and forth to return to its initial position after sealing. For example, this device moves in translation on a rail 127 situated above the sealing station, the largest dimension of which is parallel to the direction of movement of the belt 30.

As illustrated in FIG. 1 at step 5, and in FIG. 7, the complementary sealing tool 120 has at its lower end a thermosealing head 122 that can be heated, and which has a lower face 124. The head of heat sealing 122 is a height greater than the height of the pins 51, 52 above the upper face 54 of the block 50. The heat-sealing head 122 is narrower in the direction of movement of the belt 30 than the distance between the nipples 51 and 52 of such that the heat sealing head 122 can pass between these nipples. The heat-sealing head 122 is less wide in the direction transverse to the direction of movement of the belt 30 than the length of the chimney 14 between the shut-off member 88 and the orifice of the chimney 14 opening into the inside 12 of the pocket. 10, so that the seal that it makes extends only over part of the length of the chimney and that, preferably, the lower face 124 of the heat sealing head 122 does not bite on the inside 12 of the pocket 10, when the heat-sealing head 122 is applied to the chimney 14. Moreover, the heat-sealing head 122 does not touch the shutter member 88, the fastener 89 or the lever 82 during its movement. horizontal or vertical. During the passage of the pocket 10 in the sealing station, a mechanism not shown lowers the complementary sealing tool 120 vertically towards the upper face 54 of the block 50, until the lower face 124 of the head of the heated thermosealing 122 comes into contact with the chimney 14. The lower face 124 is kept in contact with the chimney 14 until the sealing of the chimney 14 is achieved.

FIG. 7 shows the heat-sealing head position 122 at the time of sealing of the chimney 14. The heat-sealing head 122 is located on the chimney 14, partially between the studs 51 and 52, and the lower face 124 of the heat-sealing head 122 completely covers a portion of the chimney 122, without biting on the inside 12 of the pocket 10, and without touching the closure member 88. As seen in Figure 7, the complementary seal is made on the section the chimney extending between the closure member and the inside of the pocket.

Once the sealing of the chimney 14 is achieved, the complementary sealing tool 120 and the heat-sealing head 122 are raised vertically while the pocket 10 is driven by the belt 30. It is no longer necessary to maintain the mechanism temporary shutter 80 in the closed position, since the chimney 14, being sealed, can no longer let air. The opening of the mechanism temporary blanking 80, that is to say its passage in the open position, is performed in step 6, downstream of the complementary sealing station.

As illustrated in FIG. 1 and in FIGS. 8 and 9, the opening of the shutter mechanism is done by an opening mechanism 130. This opening mechanism conventionally comprises an opening cam which has the shape a ramp 132 which is fixed on the support 165, that is to say that the belt 30 moves relative to it. The ramp 132 and its lower surface 134 are lowered towards the support 65 in the direction of progression of the belt 30. The ramp 132 is arranged such that when the temporary closure mechanism 80, which is in the closed position, arrives at the station 6 at the height of the ramp 132, the upper end of the rear arm 85 comes into contact with the lower surface 134 of the ramp 132. As the temporary closure mechanism 80 progresses in the direction of moving the belt 30, the rear arm 85 is pushed down by the lower surface 134 of the ramp 132. The lever 82 thus pivots about the axis 81 in the direction of clockwise. This rotation of the lever 82 is initially against the restoring force of the elastics 96a and 96b, because the restoring force exerted by the elastics 96a, 96b in extension produces a moment relative to the axis of rotation of the rod 81 which tends to rotate the lever 82 in the counterclockwise direction. Figure 8 shows the lever 82 in this intermediate position of rotation. Then, when the rotation of the lever 82 has passed the point of rotation where the arm pin 97 is aligned with the support pad 98 and the rod 81 so that the rod 81 is located above the elastics 96a, 96b which connect the arm pin 97 and the support pin 98, the elastics 96a, 96b exert a restoring force which produces a moment relative to the axis of rotation of the rod 81 which tends to pivot the lever 82 in the direction of the Clockwise. The thrust of the opening ramp 132 on the rear arm 85 is then no longer necessary, the elastics 96a, 96b coming back of themselves the temporary shutter mechanism 80 in the open position, and hold it in this position . Thus, the interaction of the rear arm 85 with the ramp 132 allows the temporary closure mechanism 80 to automatically move from the closed position to the open position as the pocket 10 moves in the installation in the direction driven, driven by the holding mechanism 40. The elastic bands 96a, 96b are therefore able to recall the temporary closure mechanism 80 to two stable positions, respectively its open position and its closed position.

Alternatively, the temporary closure mechanism 80 may comprise more than two elastics, for example four elastics.

In FIG. 1 at step 7, final sealing of the chimney 14 is carried out. Thus, the temporary closure mechanism 80 moves from the sealed position to the open position downstream of the complementary sealing station and upstream of the station. final sealing. This final sealing is performed by a final sealing tool 140, which is actuated and moved by a device identical or similar to that used for the complementary sealing (step 5). The final sealing tool 140, the final heat sealing head 142 and its lower face 144 are identical or similar to the complementary sealing tool 120, to the final heat sealing head 122, and to the lower face 124, and are not not described again. The final sealing procedure is identical to that of the complementary seal described above, with the difference that the final heat sealing head 142 can be applied to any part of the chimney 14 since the temporary closure mechanism 80 is in position. The lower face 144 of the heat-sealing head 142, however, must not bite on the inside 12 of the pocket 10.

For example, the region of the chimney 14 which is sealed by the complementary sealing tool 120 and the region of the chimney 14 which is sealed by the final sealing tool 140 may be distinct. These regions can also overlap partially. In particular, the final seal is made in the part previously obtained by the closure member, this preferably with a slight overlap with the complementary seal so as to avoid moisture traces between the two seals. Preferably, the two seals cover together the entire length of the chimney.

In FIG. 1 to step 8 and FIG. 11 is illustrated the bag release system 10 of the holding mechanism 40. This release system comprises a release bar 150 with respect to which the belt 30 moves, and which runs along and above the belt 30 on the side where the holding mechanism 40 and the shutter mechanism The end 152 of the release bar 150 located upstream in the direction of travel of the belt 30 has a tapered shape and is at the proper height so as to fit under the pocket. The side of the sealed area 16 of the bag 10 when the bag 10 is driven, and thus lift the bag 10 so that the pins 51, 52 of the holding mechanism 40 begin to slide out of the holes 21, 22 of the sealed zone 16. Where the belt 30 curves downwards, the release bar 150, which then remains rectilinear, slides the nipples 51, 52 entirely out of the holes 21, 22, and thus releases the pocket 10 of the holding mechanism 40. After its release, the pocket can for example be collected in a bin 160.

The installation according to the invention may alternatively be designed so that holding mechanisms 40 are fixed at regular intervals on the belt 30, and arranged across the latter, the holding mechanisms being spaced so as to allow a pocket to be placed on the mat between two consecutive holding mechanisms. In this case, a pocket is placed on the carpet so that its sealed area 16 pierced with holes 21, 22 and the straight line connecting the two holes 21, 22 extend substantially in a direction perpendicular to the driving direction of the carpet. 30, and that the chimney 14 extends substantially in the driving direction of the belt 30. The pocket is thus positioned on the holding mechanism by threading the two pins 51, 52 in the two holes 21, 22. Each mechanism 40 is associated with a slider 70 which opposes the clearance of the holes relative to the pins, and which extends horizontally in a direction perpendicular to the driving direction of the belt 30. Each slider 70 is held integral with a retaining mechanism or carpet 30. Each temporary closure mechanism 80 is associated with each holding mechanism 40 as described above, so that when the temporary closure mechanism 80 is in. closed assembly, the closure member 88 clamps the chimney 14 against the upper face 54 of the block 50. The closing of the temporary shutter mechanism 80 is controlled by a system operated at the outlet of the heating station, and its opening is controlled by a system operated downstream of the complementary sealing station. The complementary and final sealing tools are similar to those described above, but arranged so that their respective heat sealing heads are positioned above the chimney 14 at the moment when these heads are lowered to perform the sealing of this chimney.

Since the installation is intended for continuous treatment and for producing product contained in a pocket, the carpet 30 of the installation ideally comprises several holding mechanisms 40 and associated temporary closure mechanisms 80, which are fixed at regular intervals on Thus, several pockets are at any time carried by the belt 30, and pass successively through steps 1 to 8 described above. This passage is made in a continuous movement, without stops. Alternatively, training throughout the installation can be done step by step. In this case, the device on which the complementary sealing tool 120 is mounted may for example not move horizontally. The belt 30 then stops temporarily to advance when the holding mechanism 40 is vertical to the complementary sealing tool 120 under the latter, stopping the carpet for the time required for the complementary sealing tool 120 can seal the chimney 14.

Claims

1. A method of heat treatment of a consumable product contained in a bag (10), wherein, after introduction of the product in a bag, it is partially sealed the latter by preserving an initially unsealed area (14) forming a vent, entrains said pocket (10) in a heating station and, after heating, completely closes the pocket, characterized in that, by driving the pocket (10), the latter is held so that said initially unsealed area (14) occupies, during the passage in a sealing station, a specific position relative to a sealing tool (120) present in this station, and is carried out a complementary sealing of said zone (14) when the latter occupies said position determined.

2. Method according to claim 1, characterized in that, after heating, a shutter member (88) is applied to said initially unsealed area (14), a complementary sealing is performed while said member (88) is applied, then we stop applying the shutter member.

3. Method according to claim 1 or 2, characterized in that, to completely close the pocket (10), is carried out successively in the initially unsealed area (14) a complementary seal and a final seal.

4. Method according to claims 2 and 3, characterized in that it ceases to apply the closure member (88) between the complementary seal and the final seal.

5. Installation for the heat treatment of a consumable product contained in a bag (10), comprising means for driving (30) a bag, which contains a product and which has a partial seal preserving an initially non-contact area seal (14) forming a vent, a heating station and a complementary sealing station, disposed downstream of the heating station in the driving direction and comprising a complementary sealing tool (120) adapted to achieve a complementary seal of said zone (14) for closing the pocket (10) completely, characterized in that it comprises a holding mechanism (40) for holding the pocket relative to the driving means (30) so that in the station of sealing, said initially unsealed zone (14) occupies a predetermined position relative to the sealing tool (120) to allow said complementary sealing.

6. Installation according to claim 5, characterized in that said holding mechanism (40) is adapted to maintain said pocket (10) from upstream of said heating station in the driving direction downstream of said station. further sealing, and releasing the pocket (10) downstream of the complementary sealing station.

7. Installation according to claim 5 or 6, characterized in that said holding mechanism (40) comprises pins (51, 52) for cooperating with holes (21, 22) drilled in the sealed portion (16) of said pocket (10) on each side of said initially unsealed area (14), and means opposing clearance of the holes relative to the nipples.

8. Installation according to claim 5 or 6, characterized in that the holding mechanism (40) comprises two clamps, a first clamp (401) being intended to clamp the sealed portion (16) of said pocket (10) of a next to said initially unsealed area (14), a second clip (402) being for gripping the sealed portion (16) of said pocket (10) on the other side of said initially unsealed area (14).

9. Installation according to claim 7, characterized in that said means are formed by a strip (70) which extends, in the path of the pocket (10), above the sealed portion (16), the neighborhood of the nipples (51, 52).

10. Installation according to any one of claims 5 to 9, characterized in that it further comprises a temporary closure mechanism (80) able to temporarily seal said initially unsealed area (14) at the exit of the heating station, the mechanism (80) being in the closed position when it closes said zone (14), and in the open position when it does not close it.

11. Installation according to claim 10 characterized in that the temporary closing mechanism (80) is integral with the holding mechanism (40).

12. Installation according to claim 10 or 11, characterized in that said temporary closure mechanism (80) comprises an elastic member (96a, 96b) adapted to maintain said mechanism in the closed position.

13. Installation according to claim 12, characterized in that said elastic member (96a, 96b) is adapted to recall the temporary closure mechanism (80) to two stable positions, respectively its open position and its closed position.

14. Installation according to any one of claims 10 to 13, characterized in that said temporary closure mechanism (80) comprises a closure member (88) for gripping said initially unsealed area (14) of to prevent any fluid from passing between the inside (12) and the outside of said pocket (10), said mechanism (80) then being in the closed position, and a lever (82) rotatable about an axis (81), said member (88) being located on said lever.

15. Installation according to any one of claims 10 to 14, characterized in that it comprises a closure system adapted to bring said temporary shutter mechanism (80) from the open position to the closed position, and a system of closure. opening adapted to bring said shutter mechanism (80) from the closed position to the open position.

16. Installation according to claim 15, characterized in that said closure system comprises a closing cam (100) intended to be in contact with an arm (85) of said lever (82) during the driving of this lever in the housing. in order to rotate this lever about said axis (81).

17. Installation according to claim 15 or 16, characterized in that said opening system comprises an opening cam (132) intended to be in contact with an arm (85) of said lever (82) during the training of this lever in the installation to rotate this lever about said axis (81).

18. Installation according to claim 10 and any one of claims 5 to 17, characterized in that the complementary sealing tool (120) comprises a heat sealing head (122) intended to perform the complementary sealing of the initially non-sealing zone. -capped (14) coming into contact with said zone between the place where the latter is closed by said temporary closure mechanism (80) and the place where this zone (14) opens into the interior (12) of said pocket (10).

19. Installation according to claim 10 and any one of claims 5 to 18, characterized in that said temporary closing mechanism (80) of the initially unsealed zone (14) passes in open position downstream of the station of complementary sealing of said zone.

20. Installation according to any one of claims 5 to 19, characterized in that it further comprises a final sealing station disposed downstream of the complementary sealing station in the driving direction and comprising a final sealing tool ( 140) adapted to perform a final sealing of said initially unsealed area (14).

21. Installation according to claim 20, characterized in that said final sealing tool (140) comprises a heat sealing head (142) intended to perform said final sealing of the initially unsealed zone (14) by coming into contact with this zoned.

22. Installation according to claim 10 and one of claims 20 or 21, characterized in that said temporary shutter mechanism

(80) of said initially unsealed zone (14) passes to the open position upstream of said final sealing station of this zone.

23. Installation according to any one of claims 20 to 22, characterized in that the region of said initially unsealed zone (14) which is sealed by the complementary sealing tool (120) and the region of said area which is sealed by the final sealing tool (140) partially overlapping.

24. Installation according to any one of claims 5 to 23, characterized in that it comprises a release system (150) of said pocket (10) for releasing this pocket of said holding mechanism (40) downstream of the post additional sealing.

25. Installation according to claim 7 and any one of claims 5, 6, and 9 to 23, characterized in that it comprises a release system (150) of said pocket (10) adapted to slide said pins ( 51, 52) out of said holes (21, 22) so as to release the pocket of said holding mechanism (40) downstream of the complementary sealing station.