RU2777612C1 - Leak detection - Google Patents

Abstract

FIELD: containers.

SUBSTANCE: area of application: food industry, beverage production industry, and pharmaceutical industry during tightness checks of capped containers. Substance: invention relates to an apparatus and method for detecting leaks in capped containers using an inspection apparatus configured to determine the swelling of the capping of capped containers, as well as an analysing apparatus used to compare the swelling of the capping with a predetermined value. Each capping of the container is flattened prior to inspection using a pressurising apparatus. The pressurising apparatus includes an actuator used to apply pressure locally from the outside to each capping of the container.

EFFECT: increased reliability of leak detection for containers with light metal capping.

9 cl, 5 dwg

Description

The invention relates to a device and method for detecting leaks in sealed containers using an inspection device that is configured to detect swelling of the closure of sealed containers.

In the food industry, the beverage industry and the pharmaceutical industry, there are different ways to check the tightness of sealed containers. The commonly used tinplate container closures can, for example, be vibrated by means of electromagnetic or acoustic methods. Then, according to the behavior of the vibrations of the closures, one can judge the correct fit and tightness of the closure of the container.

Drinks containing carbon dioxide also develop overpressure in properly sealed containers. This overpressure causes resilient container closures, such as for example crown caps, to bulge slightly outwards. This characteristic swelling can be determined optically using 2D or 3D technology. If swelling is not detected, this may be due to a container leak.

Recently, beverages containing carbonic acid have been increasingly supplied with so-called pullring caps. These ring handle closures are typically made of light metal such as aluminum and can be opened by the end user by hand without the aid of opening aids. Due to the fact that aluminum is not magnetic and is much softer than conventional container closure material, the acoustic and electromagnetic leak testing methods discussed above cannot be used. Therefore, the determination of closure bulge is currently a promising method for checking the tightness of such containers.

So, the disadvantage of these aluminum closures is that once the swelling of the closure has appeared, it does not disappear by itself when the pressure inside the container drops. This situation can in particular occur when the closure of the container has a sufficiently small leakage, or when the leakage only occurred during the filling process. That is, if swelling is detected in such aluminum closures, this means precisely that after the closure there was a certain pressure inside the container. But it is not possible to judge with certainty whether there was also still sufficient pressure inside the container at the time of the inspection.

Therefore, the object of the present invention is to provide an apparatus and method in which leakage testing of light metal container closures can be performed more reliably. Another object of the invention is to provide a device and method in which leakage testing can be carried out continuously, ie without interrupting the continuous transport of the containers during the production or filling process.

Therefore, according to the invention, a device is provided with the features according to claim 1 of the claims. This device for detecting leaks of sealed containers includes an inspection device that is configured to detect swelling of the closure of the sealed containers, and an analysis device by which the swelling of the closure is compared with a predetermined value. The device also includes a pressure device, with which each container closure is flattened prior to inspection. Moreover, this device for creating pressure includes an actuator, with the help of which pressure is exerted locally on each closure of the container from the outside.

Properly sealed containers will again develop the characteristic swelling due to the pressure inside the container after flattening. Leaky containers, in contrast, have no increased or only lower internal pressure and therefore no or only less swelling will occur.

The apparatus and method of the present invention is particularly suitable for detecting leaks in sealed beverage containers. Moreover, these containers for drinks can be any commonly used container for drinks made of glass, polymeric material, PET (polyethylene terephthalate) or other suitable materials. These beverage containers are usually substantially cylindrical in shape and have a sealable, round neck opening on their upper side.

This neck opening of the beverage containers can in this case be provided, in particular, with a metal closure. The present invention is particularly suitable for performing leak detection on beverage containers whose container closures are made of a light metal such as aluminum or light metal alloys.

The swelling of container closures is preferably determined by means of an optical inspection device. Suitable optical inspection devices are point distance scanner or 2D/3D laser scanner.

In this case, it is not necessary to accurately determine the entire outline of the swelling of the container closure. The point distance scanner finds, for example, only the highest and lowest points of the top side of the closure. Due to the symmetry of the container closures, good closures have the highest point in the middle of the closure. The height difference between the highest and lowest point on the top side of the closure is then a measure of the pressure height inside the container.

Higher accuracy is achievable with commercially available 2D or 3D laser scanners. In this case, either a line profile is determined through the midpoint of the container closure (2D laser scanner), or a complete profile of the height of the container closure is drawn up (3D laser scanner). The pressure inside the vessel can then be determined even more precisely from these data.

According to the invention, prior to optical inspection, the closure of the container is flattened by means of a pressure device. The expression "flattened" here means that the closure of the container is compressed so that it extends substantially parallel to the plane defined by the mouth opening of the container.

The pressurization device is preferably located directly in front of the inspection device. In this case, the pressurizing device may be a device that serves the sole purpose of flattening the closures of the containers to be tested. This can be achieved by any pressurization device including an actuator by which each container closure is locally externally pressurized. This actuator is designed so that it can be attached to the top side of the closure. To this end, for example, purely mechanical pressure generating devices can be used, as well as mechanical pressure generating devices having hydraulic, pneumatic or hydro-mechanical elements. The actuator can, for example, also be a jet of fluid which is directed onto the container closures in order thereby to exert local pressure from the outside on each container closure. Suitable fluids for this may be, for example, air or water.

The pressurizing devices of the present invention are such devices that are suitable for applying positive pressure to the top side of the closure which compensates for the pressure inside the container so that the closure of the container extends parallel to the plane defined by the neck opening of the container.

In principle, it is not important that the closure of the container is completely flattened, and at the moment of flattening it extends exactly in the plane defined by the mouth opening of the container. To determine whether the pressure inside the container is sufficiently high, so that a correctly sealed container can be inferred, it is sufficient if a significant pressure is applied to the closure of the container. This pressure may roughly correspond to the expected pressure inside the container. But in many cases it may also be sufficient if the pressure exerted on the closure deviates from the expected pressure inside the container by up to +/-30% or by up to +/-50%.

In one embodiment, the pressurization device may include, as an actuator, a punch that is applied to the top side of each container closure. This punch preferably has a diameter which is equal to or greater than the outer diameter of the container in the region of the neck opening. In this case, the size of the contact surface of the punch ensures that the container closure can be compressed as much as possible so that the container closure extends perfectly flat, i.e. parallel to the plane defined by the neck opening of the container.

In modern bottling plants in the beverage industry, containers are transported at bottle speeds of up to several 10,000 containers per hour. The pressurization of the pressurizer according to the present invention can take place within a very short period of time. Therefore, pressure can be applied to the closures of containers during transport.

The pressurization device can also be integrated into an additional vessel treatment device. Preferably, a pressurizing device can be provided, for example, in container handling devices in which containers to be examined are held by their neck region. In this case, the holding device can be designed so that it simultaneously serves to flatten the closure of the container.

One suitable device for handling containers, in which the container is held by being clamped between its neck region and the bottom region, is, for example, a labeller. In labelers, the containers are clamped between the so-called container tulip and the bottom region, whereby the side wall region is then substantially freely accessible, so that it can be provided with a container label. In this case, the tulips for the containers form a hollow cylindrical seat for the closure area of the containers. Moreover, these tulips for containers can be modified so that they not only securely contain the container, but at the same time exert pressure on the closure of the container and flatten it, for example, to the mouth of the container. The pressurization device can be embodied, for example, in the form of a container tulip insert, which serves to flatten the container closure during labeling.

The present invention also relates to a method for detecting leaks in sealed containers. In the method according to the invention, the closure of the container is flattened by applying pressure. In this case, the device for creating pressure includes an actuator, with the help of which pressure is exerted locally on each closure of the container from the outside. After that, the container is fed for inspection of the closure of the container to the inspection device, in which the swelling of the closure of the container is determined. This swelling of the container closure is then compared with a predetermined value. If the swelling is less than a predetermined threshold value, then this is taken as a sign that the container or container closure is leaking. Then such a container is rejected from the bottling process.

The method according to the invention is suitable in particular for detecting leaks in sealed containers which are made using container closures made of light metal or light metal alloys. In particular, this method is suitable for the control of so-called aluminum ring handle closures.

Due to the properties of their material, closures made of aluminum or aluminum alloys cannot be examined by electromagnetic or acoustic methods. Although the definition of bulging closures is applicable in principle to aluminum closures, the resilience of aluminum is very low, so that once expanded closures do not themselves lie flat again on the opening of the container when the pressure inside the container is relieved. For this reason, even containers that have relatively little leakage, or that only become leaky during the filling process after sealing, have pronounced bulging of the closure. Such containers would traditionally be regarded as suitable. With the help of the present invention, it is also possible to recognize such leaky containers and reject them from the filling process.

Hereinafter, the present invention is described in more detail with the help of the accompanying drawings. This shows:

figure 1: schematic fragment of the bottling line;

figure 2: closure with a handle-ring according to the prior art;

figure 3: the neck of the container, corked capping with a handle-ring, and

figure 4: tulip for the capacity of the labeler with and without modification.

Figure 1 schematically shows a fragment of a bottling line in which containers 10 are filled with a product containing carbonic acid and then provided with a closure 12 with a ring handle. To do this, the cleaned, empty containers 10 are first transported to the filling device 14 . The containers 10 filled with the desired product are then airtightly sealed in the capper 16 by means of a closure 12 with a ring handle. Finally, the containers 10 are still in the labeler 18 provided with a label to identify the contents of the container.

Finally, the containers 10 are subjected to an overall final inspection, in which different properties of the filled, sealed container 10 are examined in several inspection devices 20, 22, 24. In the control device 26, the inspection results of the containers are evaluated. Only those containers 10 that meet the required quality criteria are put into circulation. Containers 10 that are defective, in contrast, are discarded from the filling process by means of the ejector 28 and disposed of.

One of the quality criteria that is used in the final inspection is to check the tightness of containers 10. Depending on the type of container and the type of closure, different leak detection methods are familiar to the person skilled in the art. The ability to detect leaks is somewhat limited when using closures 12 with an aluminum ring handle. Since aluminum is non-magnetic and relatively soft, traditional leak detection methods that work with acoustic or electromagnetic excitation of container closures cannot be used. Therefore, in order to detect leaks in containers 10 for beverages in which products containing carbonic acid are sealed by means of closures 12 with a ring handle, the swelling of the closures 12 with a ring handle is examined in the inspection device 24. The airtight containers 10 are pressurized, which causes the closure 12 with the handle ring to bulge.

A commonly used closure 12 with a prior art ring handle is shown in FIG. This ring handle closure 12 has a side tab or ring handle that the user can pull to open the closure. To facilitate opening, the closure 12 with ring handle is made of aluminium. Additionally, the ring-handle closure 12 can also be provided with stamped lines 15, thereby making opening even easier.

Figure 3 shows a cross-section of the sealed head of the container, having a closure 12 with a handle-ring. This closure 12 with a handle-ring in the neck region 30 of the container 10 along the entire perimeter of the neck is adjacent to the wall 32 of the container on the end side and covers the entire opening 34 of the container. However, due to the pressure inside the container, the ring-handle closure 12 does not propagate through the plane defined by the container opening 34, but the ring-handle closure 12 is squeezed outward and is therefore slightly convex.

The soft material of which the ring-handle closures 12 are made, on the one hand, makes it easier for the user to open the closure. On the other hand, the insufficient resilience of the handle closures 12 results in the bulging of the handle closure 12 due to the pressure inside the container not disappearing by itself when the pressure inside the container is reduced due to a small leak during the filling process.

For this reason, in the inspection device 24, the handle closure 12 is briefly pressurized before leaks are detected, by which the handle closure 12 is flattened. This application of pressure is carried out in the filling line shown in FIG. 1 in the labeler 18. In the labeler 18 the individual containers are held, each being clamped between their bottom and neck area, so that the side wall of the container is freely accessible and can be provided with the desired label. At the same time, in the neck region, the containers are held in the container tulip.

4a shows such a tulip 40 for a container. It includes a base 42 and a container adapter 44, on the underside of which a hollow cylindrical seat 46 is provided for the mouth region of the containers 10. As can be seen in FIG. Therefore, the ring handle closure 12 retains its swelling.

Figure 4b shows a modified container tulip 40, the modification being that an insert 48 is provided which is fitted in a hollow cylindrical seat 46. Thus, when the container 10 is placed in the modified container tulip 40 and clamped, the insert 48 contributes to additionally, pressure is also applied to the inflated ring handle closure 12 so that it collapses while the container is placed in the modified container tulip.

After the labeller 18, the containers are moved to several inspection devices 20, 22 and in particular to an optical inspection device to check the swelling of the container.

For containers 10 that leak, the pressure difference between the interior of the container and the environment is absent or reduced, so that in the labeler 18 the flattened closure 12 with the ring handle then no longer bulges at all or bulges very little. This missing or too little bulge is then recognized in the optical inspection device 24 and the container 10 can then be rejected from the filling process.

If the container 10, on the other hand, is sealed airtight, then a sufficiently high pressure inside the container causes the flattened closure 12 with the handle-ring to regain its former bulging after exiting the labeler 18. A container 10 which has a ring-handle closure 12 having sufficient swelling is considered to be airtight and may be marketed.

LIST OF REFERENCES

10 capacity

12 Capper with ring handle

13 Ring handle

14 Dispenser

15 Stamped line

16 Capper

18 Labeler

20 Inspection device

22 Inspection device

24 Optical inspection device

26 Control device

28 Output device

30 Throat area

32 Tank wall

34 Tank opening

40 Tulip for container

42 Foundation

44 Tank adapter

46 Hollow cylindrical seat

48 Insert

Claims (17)

1. A device for detecting leaks of sealed containers, including: - an inspection device that is configured to detect swelling of the closure of sealed containers, and - a pressure device by means of which each container closure is flattened prior to inspection, and - an analysis device with which the swelling of the closure is compared with a predetermined value, wherein the device for generating pressure includes an actuator, with the help of which each closure of the container is locally pressurized from the outside. 2. The leak detection device according to claim 1, wherein the inspection device for detecting swelling of the container closure is an optical inspection device. 3. The leak detection device according to claim 2, wherein the optical inspection device for determining the bulge of the container closure is a point-to-point distance scanner or a 2D or 3D laser scanner, and the distance between the highest point of the closure is determined to determine the bulge of the container closure containers and the edge point of the capping of the container. 4. A leak detection device according to one of the previous claims, wherein a device for pressurizing is located in front of the inspection device. 5. A leak detection device according to one of the preceding claims, wherein the pressure generating device includes a punch with which pressure is applied to each closure of the container. 6. Leak detection device according to one of the preceding claims, wherein at least one additional container handling device is located in front of the inspection device, and the pressure device is integrated into this additional container processing device. 7. A leak detection device according to one of the preceding claims, wherein a labeler is provided in front of the inspection device, having a container tulip, and the pressure device is made in the form of an insert into this tulip for the container. 8. A method for detecting leaks of sealed containers, which includes the following steps: - applying pressure by means of a device for pressurizing the closure of the container to flatten this closure of the container; - inspection of the closure of the container to determine the swelling of the closure of the sealed container, as well as - comparing the swelling of the closure of the container determined in this way with a predetermined value, wherein the device for generating pressure includes an actuator, with the help of which each closure of the container is locally pressurized from the outside. 9. The method according to claim 8 for detecting leaks of sealed containers, wherein the container closures are light metal closures, such as, for example, closures with an aluminum ring handle.

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