GB2272212A

GB2272212A - Removing metal caps from containers

Info

Publication number: GB2272212A
Application number: GB9322775A
Authority: GB
Inventors: Erich Steingroever; Udo Biedermann
Original assignee: Magnet Physik Dr Steingroever GmbH
Current assignee: Magnet Physik Dr Steingroever GmbH
Priority date: 1992-11-05
Filing date: 1993-11-04
Publication date: 1994-05-11
Anticipated expiration: 2013-11-04
Also published as: GB2272212B; GB9322775D0

Abstract

A metal closure 4 on a container 1 is deformed by an electromagnetic pulse acting on the closure, so loosening/removing the closure. The pulse is generated in a current pulse coil 5 surrounding the closure by the discharge current from a capacitor. The capacitor may be discharge aperiodically, periodically, or as a sine half-wave, the closure being arranged in the non homogeneous part of the magnetic field of the coil, eg in the lower, non-homogeneous part, (Figure 4). The containers may be milk bottles and the closures metal foil caps punctured by a drinking straw. A plurality of such containers with their associated closures may be advanced by a conveyor beneath a multiple coil device (Figures 7, 8). A suction device may recover the deformed closures (18, Figure 10). <IMAGE>

Description

2272212 Method and apparatus for the removal of container closures The

invention relates to a method for the removal of container closures, which consist of an electrically conductive metal, particularly aluminium or a light metal alloy, and also relates to apparatus for implementing the method.

It is known to close containers with metal caps which are folded, crimped or flanged onto or around the container opening.

A problem exists when removing such closures, particularly the closures of milk bottles or chocolate drink bottles, which consist of a thin metal foil which is punctured with a drinking straw.

The closure portions still remaining on the empty bottles must be completely removed before the bottles are re-used. To this end, the bottles pass through, for example, rotating brushes which scratch the closure residues from the bottle opening, the closure materials, such as aluminium or a light metal alloy, or glass from the container being partly pulverized and metal dust or glass splinters being released, which leads to considerable contamination of the bottling plants.

Furthermore, the bottle necks are scratched and damaged by the rotating brushes so that, as a result, an airtight further closure of the bottles is made difficult and their reusability cycle is shortened. Also, bottles with scratches tend to shatter.

The invention aims to create a method and suitable apparatus for implementing the method with which it is possible accurately to remove the closures from containers, such as milk bottles in particular and other containers, without damaging the containers.

According to one aspect of the invention there is provided a method for removing a container closure made of an electrically conductive metal, comprising the step of deforming the closure by an electromagnetic pulse acting on the closure..

It is particularly advantageous to the removal of the closure if the electromagnetic pulse acts on the edge of the preferably thin-walled closure. The electromagnetic pulse is generated with a current coil through the discharge current of a capacitor. The capacitor can be discharged aperiodically, periodically or as a sine half-wave.

The method according to the invention can be applied particularly advantageously to open or remove container closures on milk bottles or chocolate drink bottles. In this case the closure to be removed lies in the non-homogeneous part of the magnetic field of a current coil.

According to another aspect of the present invention there is provided an apparatus-for implementing the method according to the invention comprising a current pulse coil and a pulse generator.

Preferably, the current pulse coil closely surrounds the edge of the closure to be removed. The current coil may be connected to the pulse generator via a pulse transformer, if necessary.

c Preferred embodiments of the invention are shown diagrammatically in the drawings, in which:

Fig. 1 shows a section through a container with a closure tightly closing the container neck; Fig. 2 shows a cross-section through a pulse coil with the course of the magnetic field lines indicated by arrows;

Fig. 3 shows a representation of the electromagnetic pulse in the current/time diagram; Fig. 4 shows an arrangement of a pulse coil for loosening or removing the closure from the opening of a container or a drinks bottle, the opening pointing downwards; Fig. 5 shows an arrangement of a current pulse coil for'loosening or removing a closure from the opening of an upright container; Fig. 6 shows the associated current/time diagram for the loosening or removal of the closure from the upright container of Fig. 5; Fig. 7 is a perspective view of apparatus for removing the closures from incoming empty milk bottles standing next to one another in transport crates in a milk bottling plant; Fig. 8 shows a plan view of part of the apparatus of Fig. 7 for simultaneously removing the closures from several empty milk bottles or the like standing next to one another in transport crates; Fig. 9 is a perspective view of the essential parts of a device for simultaneously removing the closures from several milk or drinks bottles moving behind each other on a conveyor device; and Fig. 10 shows a perspective view of a further modified conveyor device with a device arranged above it for simultaneously removing the closures from several milk bottles or the like standing next to one another in transport crates.

Fig. 1 shows a deformed, tightly closing closure 4 on the container edge or container neck 2 of a drinks bottle or a container 1 before a high electromagnetic pulse generated by a current pulse coil 5 has acted on the closure 4. The container neck 2 has one or more grooves 3 for the edge 4a of the closure 4.

Fig. 2 shows the current pulse coil 5, which has a passage 6 corresponding to the shape of the container neck 2. It can be round, or rectangular or polygonal.

The electromagnetic pulse can be generated aperiodically or periodically or even as a sine halfwave, as shown in Fig. 3.

The electromagnetic pulse is produced by the rapid discharge of an electrical capacitor. The pulse induces a high current in the closure 4, which attempts to escape the magnetic field of the pulse. The arrangement of the closure, as shown in Fig. 4 or 5, gives the direction of acceleration.

The method according to the invention is particularly suitable for removing closures 4 or residues thereof from the empty containers or bottles 1. To do this the current pulse coil 5 is arranged so that the axial force of the electromagnetic pulse prevails on the closure 4. This can be achievedr for example, in that the closure 4 is arranged in the non-homogeneous part of the magnetic field of the current pulse coil 5, i. e. outside the centre of the coil in the axial direction.

Such an arrangement of current pulse coil 5 and container 1 is shown in Fig. 4. The half-open or punctured closure 4 of an empty bottle or of a container 1 is arranged in the non-homogeneous field of the current pulse coil 5 and is stripped away by the current

9 P pulse in the direction of the arrows 9.

The method and apparatus for implementing the method according to the invention are particularly suitable for removing the lids or closures 4 made of light metal, aluminium or other materials which are good conductors, from empty bottles for milk and milk products.

Figs. 5 to 10 show the removal of the closures 4 from upright containers 1 or milk bottles 10 and the like.

If the container 1 or the milk bottle 10 with the closure 4 to be removed is standing upright, during an aperiodic pulse the current pulse coil 5 must be arranged underneath the closure 4., which is not always possible'because of the shape of the container or bottle.

During a sine pulse (first half-wave), however, the current pulse coil 5 can surprisingly lie above the closure 4, and this is nevertheless deflected upwards by the coil 5 (arrows 9 in Fig. 5). This effect results from a phase shift between the primary current I1 of the current pulse coil 5 and the secondary current 12 thereby induced in the closure 4, as shown in the current/time diagram of Fig. 6.

From tO to tl, both currents I1 and 12 are in opposite directions and repel one another, although the closure 4 cannot escape. Between tl and U both currents I1 and 12 are in the same direction, however, and attract one another so that the closure 4 is deflected upwards in the direction of the arrows 9 in Fig. 5.

It is appropriate for the upper edge of the closure 4 to lie level with the lower edge of the pulse coil 5. Several containers 1 or milk bottles 10 or the like located in series on a conveyor belt 11 or in a transport crate 16 (Figs. 7 to 10) can thus be simultaneously freed of their closures with a multiple coil system 19 (Fig. 8), the coil system being lowered onto them or they being raised into it (Figs. 7 and 8).

Figs. 7 and 8 show a device 18 with such a multiple coil system 19 for removing the container closures 4. The multiple coil system 19 of the deformation device 18 is connected to a pulse transformer which is not shown or directly to a pulse generator 20, the current pulse coils 5 arranged next to one another on a coil support 21 with several openings 22 being wound in opposite directions and being connected in series one after the other to the pulse generator 20 via common connecting cables 23 and 24.

An extractor hood 25 with a suction fan 26 is located above the deformation device 18 for extracting the closures 4 removed from the container or bottle necks.

Two further devices of this kind are shown in Figs. 9 and 10. In Fig. 9 milk bottles 10 arrive standing behind one another on a conveyor belt 11 and pass through a device 18 for removing the closures 4.

The device 18 is movable up and down in the direction of the double arrow 13 and has several current pulse coils 5 in series one after another. After lowering onto the container or bottle necks 2 it is moved with the conveyor belt 11, to be returned to the next initial position again according to the movement diagram 14 after the closures 4 have been removed. The closures 4 are always removed in the area 15 of this movement diagram.

This also applies to the representation in Fig. 10 in which several milk bottles standing next to one another in transport crates 16 pass under the device 18 for removing the closures 4.

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Claims

1. A method for removing a container closure made of an electrically conductive metal. comprising the step of deforming the closure by an electromagnetic pulse acting on the closure.

2. A method according to claim 1, wherein the electromagnetic pulse acts on the closure to deform a peripheral edge of the closure.

3. A method according to claim 1 or 2, wherein the electromagnetic pulse is generated with the aid of a current pulse coil supplied with the discharge current of a cap;acitor.

4. A method according to claim 3, wherein the capacitor is discharged aperiodically.

5. A method according to claim 3, wherein the capacitor is discharged periodically.

6. A method according to claim 3, wherein the capacitor is discharged as a sine half-wave.

7. A method according to any of claims 1 to 6, wherein the closure to be deformed is arranged in the non-homogeneous part of the magnetic field of a current pulse coil.

8. A method according to any of claims 1 to 7, wherein the closure to be removed lies in the lower nonhomogeneous part of the magnetic field of a current pulse coil and is deflected upwards by the coil with a sine halfwave pulse.

9. A method according to any of claims 1 to 8, wherein the closure is deformed to remove the closure from a container for milk or milk products.

10. Apparatus for implementing the method according to any of claims 1 to 9, comprising a current pulse coil and a pulse generator.

11. Apparatus according to claim 10, wherein the current pulse coil is arranged to surround closely the edge of the closure to be deformed.

12. Apparatus according to claim 10 or 11, wherein the current pulse coil is connected to the pulse generatot via a pulse transformer.

13. A method for removing a metal closure from a container substantially as hereinbefore described with reference to the accompanying drawings.

14. Apparatus for removing a metal closure from a container substantially as hereinbefore described with reference to the accompanying drawings.