DE2157614A1 - Method and system for checking the tightness of containers under excess gas pressure, in particular aerosol cans - Google Patents

Description

PATENTANiWAU

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HELMET GORTZ. _{o1Ci7ß1 /}

6 Frankiu.t ss.i Main 70 4 I 07 D I H

Schned <enhofstr. 27 - Τ · Ι. 61 70 79 Dld / HGM

Peter Schönenberger, Wollerau ZH

Process and system for checking the leakage of gas pressures Containers, in particular for aerosol cans

The present invention relates to a method for checking the tightness of containers under excess gas pressure, especially aerosol cans. The invention relates to also a system for carrying out the process mentioned.

In aerosol filling plants, the containers that are under gas overpressure are usually filled with an automatic Transport device passed through a heated water bath. The leaking containers are based on the ascending Bubbles recognized and sorted out.

The invention is based on the object of determining the presence of leaky containers on the basis of the rising bubbles to be determined automatically and thus save a manpower.

The method according to the invention is characterized in that that the containers are immersed in a liquid, the possibly rising gas bubbles indicating a leak are collected below the liquid level and fed to a gas detection device.

The system according to the invention for carrying out the aforementioned method is provided by a device for collecting of any gas bubbles that may occur and to Rob / cfa

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their feeding to a designated for the detection of such bubbles Gas detection device, at least the collecting device being provided to be immersed in a vessel containing a liquid to be featured.

An exemplary embodiment of the subject matter of the invention is explained in greater detail below with reference to the drawing. The drawing shows the container 1 to be tested completely immersed in the preferably heated water bath. Above this is the hood 2 for collecting the rising gas bubbles. This hood 2, which is also attached under water, collects the rising leakage bubbles and feeds them to the gas detection device 3. The gas detection device has an insulating body made of non-conductive, waterproof material, preferably made of heat-resistant plastic with low water absorption, e.g. from "DeI-rin". On the underside, the insulating body is provided with a funnel-shaped opening which opens into a narrow hole U. The hole and its immediate vicinity are referred to below as the test volume. The device is provided with two electrodes, one of which is arranged in a bore formed in the insulating body above the hole k , while the second one surrounds the insulating body. The best, preferably made of stainless steel. the electrodes are electrically isolated from one another by means of the insulating body and connected to an electrical voltage source. An electric current therefore flows through the water as the conductive liquid, which inevitably flows through the test volume, since the gas detection device is not completely in the water. ' If a gas bubble gets into the test volume, the electrically effective cross-section of the test volume becomes smaller. This increases the electrical resistance and thus the current decreases. As soon as the current falls below a certain value or the current variation per unit of time assumes a certain size, a monitoring device emits an alarm signal in order to report the presence of a bubble. The sizes of the various bubbles can also be reported, since the electrically effective cross-section becomes smaller as the bubble size increases. This increases the electric

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see resistance and thus the current becomes smaller. A high one The current value corresponds to a small bubble, whereas a low current value corresponds to a large bubble.

The containers to be tested are placed one behind the other under the by means of a continuous transport system Hood carried out and tested in the manner described. Several devices of the type described can be side by side arranged and combined into one unit. With this arrangement, the test time is extended and the Test objects checked over a distance of about one meter in length. Due to compact design and stretchable electrical The unit is then portable and can be taken from department to department by staff. This Process does not require a pump.

There may be errors in the above-mentioned device ..., show through parasitic bubbles occur. Due to cavities in the transport system as well as due to the negatively cambered At the bottom of the container, the air is dragged into the water, which rises in the form of gas bubbles in the water. These Bubbles interfere with the measurement process, since only the Tester for leakage cans is desired. To avoid this, several test devices are arranged (the can be structurally combined into a unit), which of the cans to be tested in a certain series and timing are served. A leakage can leaves the testing devices address them in the correct order and time. Parasitic air bubbles operate the test devices in any time and order. An electronic selection process recognizes the leakage cans based on the ones mentioned Criteria and actuates a relay.

The size of the test volume is for sensitivity of the gas detection device. With a small test volume, that is, with high sensitivity, the Gas bubbles no longer slip through the small hole because the surface tension is too high. The device works but anyway, you just have to remove the

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Bladder be tipped. The surface tension of the water can be reduced by adding detergents.

In another exemplary embodiment, not shown, a second measurement volume can be provided which For reference purposes it is used to show the fluctuations in the electrical conductivity of the liquid, especially when used to compensate for well water, whereby the method of the bridge circuit can be used.

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Claims (1)

Patent claims: lj) Procedure for leakage control from under gas overpressure standing containers, in particular aerosol cans, characterized in that the containers are immersed in a liquid, the possibly rising gas bubbles indicating a leak are collected below the liquid level and a gas detection device are fed. 2. The method of claim 1, wherein the to be tested -Containers are moved one behind the other through the liquid, characterized in that the container transport when leaked bubbles are detected stopped and a fault signal is given. 3. The method according to claim 1, in which the containers to be tested are moved one after the other through the liquid, characterized in that a selection process is used to prevent the gas detection device from responding to parasitic bubbles is carried out in order to only and timing of moving cans. tf. Plant for carrying out the method according to claim 1, characterized by a device for collecting given, Any gas bubbles that may occur and for their supply to a gas detection device intended to detect such bubbles, wherein at least the collecting device is provided - in a one To be immersed in a liquid containing vessel. 209823/0757 5. Plant according to claim 4, characterized in that * a transport device is provided to check the · ^, - ~ to guide the container through a test liquid bath. 6. Plant according to claim 4, characterized in that, the Gasblasenauf catching and supply device consists of a collecting hood, which is designed to consist of the to collect leaky containers leaking leak bubbles, collect them and through a located on the top of the hood To let through the opening to the gas detection device to feed. 7. Plant according to claim 4, characterized in that the gas detection device consists of an electrically conductive liquid existing test volume having a predetermined cross section or electrical resistance which the leak bladders are guided. 8. Plant according to claim 7, characterized in that two connected to an electrical voltage source, Electrodes which are electrically insulated from one another by an insulating body are provided, which electrodes are connected to the conductive liquid and form a closed circle with the test volume. 9. Plant according to claim 4, characterized in that a monitoring device is provided in order to prevent the as a result of the passage of a leakage bubble through the test volume output an alarm signal if there is a reduction in cross-section or an increase in resistance. 10. Plant according to claim 8, characterized in that the two electrodes and the insulating body are essentially tubular and are arranged concentrically to one another, that the insulating tube is arranged between the two electrode tubes and concentrically to them and that the test, volume-forming bore is formed in the lower end of the insulating tube. 11. Plant according to claim 4, characterized in that a device intended to display the respective bubble size is provided which, as a result of the changes - 6-
20 9823/0757 21576H der'Grossen of the bubbles going through the test volume occurring Shows changes in the current value. 12. Plant according to claim U, characterized in that that to avoid the response of the gas detection device a selection device is provided for parasitic bubbles which limits the test method to only those bubbles, which are in a certain order and time sequence moving cans. 2098 2 3/0757 Blank page