WO2001009583A1

WO2001009583A1 - Method and device for controlling the sealed condition of packages whereof at least one part is heat sealed

Info

Publication number: WO2001009583A1
Application number: PCT/FR2000/002169
Authority: WO
Inventors: Patrice Camu; Willy Grandke
Original assignee: Patrice Camu; Willy Grandke
Priority date: 1999-07-30
Filing date: 2000-07-28
Publication date: 2001-02-08
Also published as: FR2797051B1; FR2797051A1

Abstract

The invention concerns a method and a device for controlling the sealed condition of packages whereof at least one part is heat sealed. The method consists in: setting the package (1) in a sealed enclosure (2); generating a vacuum in said enclosure (2); maintaining said vacuum for a predetermined time interval during which or at the end of which a possible variation of pressure is detected; comparing said pressure difference to a threshold value and in case the difference is greater than the threshold value, the package (1) is considered to be defective.

Description

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Before the expiry of the period provided for the modification of the With regard to two-letter codes and other abbreviated claims. will be republished if modifications are made, refer to the "Explanatory Notes Relating to Codes and Abbreviations Received" appearing at the beginning of each ordinary issue of the PCT Gazette

(57) Abstract: The invention relates to a method and a device for checking the leaktightness of packaging, at least part of which is closed by heat sealing. Thus, the method consists in: depositing a package (1) in a sealed enclosure (2); creating a depression in said enclosure (2); to maintain this depression for a determined period during or at the end of which a possible variation in pressure is detected; to compare this with a threshold value and if it is greater than the latter the packaging (1) is considered to be defective. METHOD AND DEVICE FOR TESTING THE SEALING OF PACKAGES OF WHICH AT LEAST ONE PART IS CLOSED BY THERMAL WELDING

The invention relates to a method and a device for checking the leaktightness of packaging, at least part of which is closed by heat sealing.

The invention relates to the field of devices for checking the leaktightness of heat-sealed packaging in the context of a production chain for food, pharmaceuticals or other products contained in such packaging.

In this regard, if the invention will find an application particularly in the field of control of flexible plastic bags, it relates more generally to any packaging of which at least part is closed by thermal welding likely to present risks of leakage. .

More and more frequently, food products, but also pharmaceutical products, in particular in the liquid or pasty state, are packaged in plastic or composite packaging defining a container into which said product is precisely poured. Then, this container is closed, either by heat sealing the edges of the opening through which the product has been poured, or by means of a cover element which is, here again, heat sealed.

In itself, this sealing technique by heat sealing is very reliable. It only prevents that if the packaging is faulty and leaks, this can cause serious problems of contamination of the contents.

Obviously, if the leak is apparent, it is quite easy to detect a defective packaging before consumption. However, in the context of micro-leakage of the content, without being able to escape from the packaging, is exposed to atmospheric air, therefore is likely to be contaminated by bacteria.

Also, a method and a device for checking the leaktightness of such packaging have been devised which makes it possible to detect, very quickly and without slowing down the production chain, defective packaging with a view to removing it from this chain to avoid any risk of accident, in particular by subsequent contamination.

Thus, the invention relates to a method for checking the tightness of packages 1, at least part of which is closed by heat sealing, characterized in that:

we place a package in a sealed enclosure

a depression is created in said enclosure;

- This vacuum is maintained for a determined period during or at the end of which a possible variation in pressure is detected;

- this is compared to a threshold value and if it is higher than the latter the packaging is considered to be defective.

Advantageously, when, in a given enclosure, a defective packaging has been detected, this enclosure is cleaned. It can then be subjected to a tightness test cycle.

In addition, if, successively, two packages are detected as defective in a given enclosure, the latter is subjected to a thorough leak test. According to the invention, for flexible packaging, provision is also made, in addition to checking the pressure variation, to simultaneously detect during this checking a deformation of the tested packaging. The information thus collected makes it possible either to confirm a measurement of pressure variation and thus to reinforce the reliability of the control, or, in the case of flexible packaging with several compartments, to detect a leak between compartments.

The invention also relates to a tightness control device allowing the implementation of the above method, characterized in that it comprises:

at least one enclosure provided with an access opening capable of being sealed;

- Means for depositing in this enclosure, through said opening, a package to be checked;

- Means for creating in this enclosure a depression of a predetermined value;

- means for detecting a pressure variation in said enclosure for a given duration;

- means for comparing the pressure variation detected with respect to a threshold value;

- means of removing defective packaging;

- And means of transporting a non-defective controlled packaging towards a downstream processing unit. Advantageously, the device also comprises means for cleaning an enclosure in which a defective packaging has been checked.

According to a preferred embodiment, the device comprises a plurality of enclosures evolving according to a looped circuit and subjected to a forward movement step by step, in these enclosures being successively deposited a packaging for control.

According to another feature of the invention, the device comprises, in an enclosure, means for detecting deformation, during leakage control, of a package, in particular of the flexible type.

Other objects and advantages of the present invention will emerge during the description which follows, relating to an embodiment.

The understanding of this description will be facilitated by referring to the attached drawing in which:

- Figure 1 is a schematic and plan view of an embodiment of the packaging tightness control device according to the invention

- Figure 2 is a schematic view in partial section of an enclosure capable of being closed in a sealed manner, in this enclosure being caused to take up the position of the packaging to be checked.

As shown in the figures of the attached drawing, the invention relates to the field of packaging tightness control devices, at least part of which is closed by heat sealing. In this connection, such packaging can be of the flexible, semi-flexible or even rigid type and can contain various types of product, in particular food, pharmaceutical or other.

By way of example, such packages can be in the form of pockets defining, consequently, a container into which any product can be introduced, this container or pocket then being closed by heat sealing the edges of the filling opening.

Furthermore, different materials can enter into the composition of these packages, the invention finding its application from the moment that a risk of leakage can arise at the level of a heat-sealed closure.

In the end, the method for checking the leaktightness of such heat-sealed packages consists in depositing a package 1, shown diagrammatically in FIGS. 1 and 2, in an enclosure 2 capable of being sealed.

It will be noted that if this operation can be carried out manually, use will preferably be made of appropriate automatic means 3 consisting, essentially, of means 4 for transporting these packages 1 from an upstream processing unit 5 in the direction of said device. 1 as well as suitable gripping means (not shown) for, precisely, taking these packages 1 and depositing them, preferably one after the other, in such an enclosure 2. Note, in this regard, that these packages can be placed on transport trays and can therefore be driven, with their transport tray, into test enclosure 2.

As will appear further in the description, the device for implementing the method may include several speakers 2, 2A, 2B ... evolving according to a looped circuit 6.

Anyway, according to the method according to the invention, inside this sealed enclosure 2, containing the packaging 1 to be tested, a vacuum is created of a determined value, then the this depression is maintained for a given duration during or at the end of which it is detected, precisely, a variation of this pressure.

Note that two methods can be used for this, the first known as constant pressure and the second variable pressure.

Thus, for the implementation of the first method, there are means ensuring throughout the duration of the measurement a constant depression in the enclosure 2 knowing that one comes to measure in parallel, in particular through of a flow meter, the volume of air that it was necessary to take from this enclosure 2 to maintain the vacuum at its determined value. Then, this quantity of air taken during the measurement is compared with a threshold value, knowing that if it is greater than the latter, the packaging is considered defective. This is then evacuated to a rejection area.

Otherwise, this packaging is sent to a downstream processing unit, for example packaging, pasteurization or other.

The variable pressure method consists, on the contrary, in bringing vacuum 2 to a determined pressure (depression), then, beyond a given duration, to measure this pressure again to compare it at the initial pressure, taking into account that if the variation is greater than a threshold acceptable, the packaging is again discarded because it is considered not waterproof.

Preferably, after a control cycle of a defective packaging, one proceeds to the cleaning of the enclosure 2 which can be soiled by the product contained in this packaging. The enclosure 2 can be rinsed with water, in particular at temperature or using other products, knowing that such a first cleaning step can be followed by a second sterilization. In particular, the enclosure can be swept and dried with sterile air, just as one can spray a jet of superheated steam.

Likewise, when successively in the same enclosure 2, two packages are detected to be defective, one proceeds, preferably, during the following cycle to a leak test of this enclosure, in order to verify that the variation of the detected pressure does not correspond not to a defect in the tightness of said enclosure.

According to the invention, provision is also made, in the very particular case of flexible packaging, to detect, simultaneously, during the period during which the vacuum is maintained in the enclosure 2, a deformation of the packaging tested.

More particularly in such an enclosure 2, detection means are provided in the form of one or more suitable sensors which, when brought into contact with the packaging once this enclosure 2 is closed, are capable of detecting a possible deformation of this packaging, in the negative pressure phase. This can either confirm a measurement of pressure variation in enclosure 2, therefore a leak of the tested packaging, or indicate a leak between several compartments of the same packaging. It should, in fact, be observed that it is known, in particular in the food sector, such flexible packaging which, through an appropriate compartmentalization, is capable of containing distinct products generally intended to be brought into contact that 'at the time of their consumption.

Preferably, there will be provision, under these conditions, for detection means comprising as many sensors as there are compartments in the packaging to be tested. Furthermore, these sensors will be dependent on handling means capable of positioning each of them in contact with the compartment corresponding to the level of the packaging, moreover, maintained in a predetermined position in the enclosure 2 thanks, again, to suitable prepositioning means. Note, in this regard, that such prepositioning means can be associated with the support plate contributing to the transport of a packaging through the device.

Thus, such sensors are capable of revealing, in the event of a deformation of a compartment relative to another adjacent one, that a leakage problem exists between compartments, this when, moreover, no variation in pressure has was detected during testing in enclosure 2.

As already indicated above in the description, the device allowing the implementation of this method according to the invention, can comprise several enclosures 2, 2A, 2B ... evolving according to a looped circuit 6. As visible in FIG. 1, in particular, this device can be in the form of a carousel defined by a crown 7 subjected to a rotation at a speed and / or with a determined pitch and on the periphery of which are the speakers 2, 2A, 2B ... for reception of packaging to be checked. As shown in FIG. 2, such an enclosure 2 comprises, according to an exemplary embodiment, a bell 8 capable of surmounting, in a sealed manner, a tray 9 for receiving a package 1, or even the support tray contributing to the transport of this packaging. It is subjected, as the case may be, to this plate 9 or to the bell 8, a vertical movement of ascent and descent for either opening the enclosure 2, as shown in solid lines in this figure 3 or, on the contrary, closing that -this corresponding to the dashed line representation of the plate 9.

Likewise, as can be seen very diagrammatically in this FIG. 2, the control of opening of the plate 9 can be ensured by suitable mechanical means, in particular a cam system, while the closure can be controlled by elastic return means 10 s extending under the plate 9.

Of course, the seal between the bell 8 and this plate 9 is ensured by means of suitable sealing means 11.

The enclosure 2 is, moreover, capable of being connected to means for creating a vacuum, in particular a vacuum pump, as well as to means for bringing to atmospheric pressure 13. It is also connected to a pressure switch and / or a flow meter 14 and / or any other suitable sensor from which the information can be taken for the implementation of one of the methods previously mentioned.

This enclosure 2 could also be connected to means for supplying water and / or steam and / or sterile air and / or any other cleaning product for cleaning it, and if necessary, drying and sterilizing it. 10

In addition, as already indicated above, such an enclosure 2 can accommodate means for detecting the deformation of a package, in particular of the flexible type, while a negative pressure is established in the enclosure 2.

To return to the number of speakers 2 of the device, it will obviously be chosen as a function of the rate of the packages 1 to be tested. There is also the time during which the measurement takes place, that is to say the detection of the variation in pressure in such an enclosure 2. In this regard, to optimize the test operation, it is advisable to 'Adjust the internal volume 15 of the enclosure 2 to that of the packaging to be tested. For this purpose, inserts 16 can be installed inside this enclosure 2 which, in the event of a small packaging test, make it possible to reduce the volume of this enclosure 2.

Preferably, such inserts 16 constitute, moreover, means for positioning and maintaining a package 1, in particular when the latter is of flexible nature, this in order to prevent such a package from breaking under the effect of depression. In addition, such positioning or prepositioning means as already indicated above may prove essential to authorize the intervention of the deformation sensors.

Note, again, that such means for holding and positioning a package can be defined to present the latter, the heat-sealed part facing upwards.

It is quite common, in fact, for at least part of the volume of the packaging to be occupied by air or even any other gas, in particular inert, which by coming to be placed immediately under this heat-sealed part facilitates the detection of micro-leaks capable of being plugged 11

temporarily, during the test operation, by the same product contained in this packaging.

As can be seen in FIG. 2, such inserts 16 constituting, where appropriate, means for holding and positioning a package 1, can be installed both at the level of the plate 9 and of the bell 8. In addition, they are , preferably, of an interchangeable nature allowing the device to be adapted to different packages. As already mentioned above, in the event that a package comes to be positioned in enclosure 2 with its support plate, the latter can be equipped with such holding and positioning means capable, moreover, of playing at least partially, the role of insert to optimize the volume in which it is a question of establishing a depression in an enclosure 2.

Insofar as, beyond a test cycle, a defective packaging is detected and a cleaning cycle of the corresponding enclosure 2 has to be carried out, this aspect should be taken into account in determining the number of speakers making up the device. Thus, this number of enclosures will be chosen to be around 25% higher than the optimum number determined in relation to the packaging rate to be tested and the duration of a test.

It will be noted that if, as shown in FIG. 1, the supply zone 17 in packaging to be tested is located immediately after the evacuation zone 18 of the packaging tested, in the direction of rotation of the looped circuit 6 taken by the speakers 2, 2A, 2B ..., we can still imagine any other layout taking into account, in particular, that a tightness test cycle can correspond to more than one revolution of an enclosure 2 at the circuit looped 6. Of course, in these conditions, it will be necessary, in the order of successive filling of the enclosures 2, 2A, 2B ... to take this parameter into account. Through 12

example, when during a cycle an enclosure 2 is made to execute between one and two turns, the number of enclosures 2, 2A, 2B ... will be chosen odd and only one enclosure out of two will be supplied with power. feeding area level 17.

It is obviously possible to envisage any other configuration taking into account that the supply cycles, the advance of the enclosures 2, 2A, 2B ... along the looped circuit 6 and the evacuation of the tested packages, can be totally managed through a microprocessor acting on the different motor means.

Note, again, that this management of the device can be ensured from a control console provided capable of keeping an operator informed of the progress of a leakproofness test of a package 1 at each of the enclosures 2, 2A, 2B .... In particular, signaling means can be provided at this control console capable of informing the operator that during two consecutive test cycles in a given enclosure, a defective packaging was detected, forcing the operator to check the tightness of this enclosure. In this regard, the management microprocessor can be programmed to make such an enclosure inoperative until it is controlled.

Claims

claims

1. Method for checking the leaktightness of packaging (1) at least part of which is closed by heat sealing, characterized in that:

- a package (1) is deposited in a sealed enclosure (2);

- A depression is created in said enclosure (2);

- this is compared with a threshold value and if it is greater than the latter the packaging (1) is considered to be defective.

2. Control method according to claim 1, characterized in that, when a defective packaging (1) has been detected in a given enclosure (2), cleaning of this enclosure (2) is carried out, if necessary, by a sterilization operation.

3. Control method according to any one of the preceding claims, characterized in that if it is detected consecutively in the same enclosure (2) two defective packages, a leak test of said enclosure is carried out ( 2).

. Control method according to any one of the preceding claims, characterized in that during the depression in the enclosure (2), a possible deformation of the packaging (1) tested is detected.

5. A tightness control device allowing the implementation of the method according to any one of claims 1 to 4, characterized in that it comprises:

- at least one enclosure (2) provided with an access opening capable of being sealed;

- Means for depositing in this enclosure (2), through said opening, a package (1) to be checked;

- Means for creating in this enclosure (2) a depression of a predetermined value;

- means for detecting a pressure variation in said enclosure (2) for a given period;

- means of evacuating a defective packaging (1)

- And means for conveying a non-defective controlled packaging (1) towards a downstream processing unit (5).

6. Control device according to claim 5, characterized in that in an enclosure (2) are provided means for detecting, in the form of one or more sensors, the deformation of a package (1).

7. Control device according to claim 5 or 6, characterized in that it comprises a plurality of speakers (2, 2A, 2B ....) evolving according to a looped circuit (6), more particularly in the form of '' a carousel defined by a crown (7) subjected to rotation at speed and / or step determined and on the periphery of which the enclosures (2, 2A, 2B, etc.) are located for the reception of packages (1) to be checked.

8. Control device according to any one of claims 5 to 7 above, characterized in that an enclosure (2) comprises a bell (8) provided capable of surmounting, in a sealed manner, a receiving plate (9) a package (1) to be tested, said receiving plate (9) or the bell (8) being provided capable of adopting a vertical movement of ascent and descent to, as the case may be, open the enclosure (2) or , on the contrary, close it.

9. Control device according to any one of claims 5 to 7, characterized in that an enclosure (2) is connected to means for creating a vacuum, in particular a vacuum pump, as well as to means for setting to atmospheric pressure (13) and to a pressure switch and / or a flow meter and / or any other sensor (14) provided capable of detecting a pressure variation in this enclosure (2).

10. Control device according to any one of claims 5 to 9, characterized in that an enclosure (2) is connected to means for supplying water and / or steam and / or sterile air and / or any other cleaning product for cleaning and, where appropriate, drying and sterilization.

11. Control device according to any one of claims 5 to 10, characterized in that in an enclosure (2) are able to be implanted inserts (16) to adjust the volume of this enclosure (2) to the size of the packages (1) to be tested and / or to position and maintain a package (1).

12. Control device according to any one of claims 5 to 10, characterized in that a package (1) to be tested is arranged on a support plate with which it is introduced into the enclosure (2), on this tray being provided means for prepositioning and holding this packaging (1) defining, at least in part, inserts for adjusting the volume of the enclosure (2).

13. Control device according to any one of claims 5 to 12, characterized in that the management of its operation is ensured by means of a microprocessor from a control console provided capable of keeping an operator informed of the 'state of progress of a leakproofness test of a package (1) in an enclosure (2, 2A, 2B ...).