WO1981000250A1

WO1981000250A1 - Linear transfer machine and process using magnetic induction for the sealing of containers

Info

Publication number: WO1981000250A1
Application number: PCT/FR1980/000119
Authority: WO
Inventors: M Cros
Original assignee: Ato Bouchon Rapid; M Cros
Priority date: 1979-07-12
Filing date: 1980-07-10
Publication date: 1981-02-05
Also published as: BE884275A; FR2460885B1; ES8104132A1; ES494163A0; FR2460885A1; EP0032909A1; IT8049211A0; IT1128127B

Abstract

Process for thermosealing a cap (26) on a container (30) by circulating in the magnetic field produced by an elongated conducting loop (31) a slit crown (34) called "focusing relay", said relay being intended to intercept an important flux issued from the loop with a view to rendering at the vicinity of the metal portions of the cap a flux substantially equal to the intercepted flux. The preferred machine for implementing the above-mentioned process comprises two conveyor belts (23), one called a presser belt and the other one called a carrier belt, delimiting a passageway (4) for the containers. Application to the sealing of containers such as bottles, pots, etc.

Description

Linear transfer machine and method employing high frequency magnetic induction for plugging containers.

The present invention is in the field of techniques for capping containers, such as flasks, jars, or the like, and its subject is a method of induction heat sealing as well as preferred means of implementing said method and a capping machine and / or heat-sealing the containers.

We know in particular from a French patent n ° 1 461 000 a process and a device for applying sealing membranes on containers; according to this method and on condition that either the membrane comprises electroconductive constituents, or that such electroconductive constituents are constitutive of the parts of the container adjacent to the membrane, an alternating magnetic field of high frequency induced in the metallic parts of the eddy currents which heat these parts and allow the fusion of a sealing material such as wax between the membrane or cover and the mouth of the container; such a process is implemented by means of a heat-sealing head shaped to surround and apply the seal on the mouth, the heat-sealing head comprising one or more electrically conductive turns preferably cooled by internal circulation and constituting an organ , said inductor, producing the magnetic field. According to this process, the heat sealing head moves at the same time as the container by means of an appropriate transfer machine of the so-called carousel type.

The aforementioned process and its means of implementation have undeniably constituted a considerable progress in therra-sealing techniques, in comparison for example with previous processes in which the heat was communicated to the seal by conduction; However, it is understandable that the supply of high-frequency intense current and of coolant poses delicate protection and wear problems, since the member to which they are applied is movable relative to the frame of the transfer machine. .

It will also be noted that, to the knowledge of the Applicant, the transfer machines proposed up to this point for plugging the containers are of the circular transfer type, also called barrel or carousel; in the general case of purely mechanical capping operations taking place during transfer, these machines are relatively simple in design and are fairly reliable; we can however blame them for a certain weakness in cadence, but their low cost allows multiplying them to overcome this drawback; it is different when, in addition to the actual plugging, they are subjected to the additional operation of heat sealing, and in particular of high frequency induction heat sealing.

A first object of the present invention is to provide a transfer machine for capping and / or thermosealing of containers at a very high rate, independently of the thermosealing means used. A second aim is to propose a high frequency induction heat sealing process in which the production of the magnetic field is carried out at a fixed station, thereby eliminating the drawbacks of the mobility of the inductor.

According to the present invention, an automatic machine for capping and / or heat sealing a container by means of a cover and / or a capsule, is generally characterized in that the transfer of the containers is linear, or rectilinear, on at least the part of the machine where the capping and / or heat sealing operations are carried out, and mainly in that said machine comprises for cooperation a first so-called lower conveyor or even carrier on which the containers are placed, said carrier conveyor being rectilinear on at least part of its path, a second so-called upper or presser conveyor, said second conveyor being, on part of its path, rectilinear and substantially parallel to said rectilinear part of the first conveyor and being located at -above it at a distance very slightly less than the height of the capped containers, said second conveyor having an inlet section inclined upwards with a gentle slope, said second conveyor supporting equidistant capping and / or heat-sealing members, and finally motor and transmission means for isokinetically animating said first and second conveyors.

It follows from these general provisions that it is possible, while respecting an imposed residence time of the containers on the machine, to increase the speed of transfer, therefore the rate, provided that the length is increased, which can be achieved at much lower cost and without significantly increasing the surface area compared to circular transfer machines. Such a machine comprises, as is known for circular machines, in the vicinity of its inlet section at least one screw, and preferably two superimposed, constituting an evenly distributed means of the containers on the carrier conveyor, said screw at least being animated in synchronism with said conveyors.

Also preferably, the carrier conveyor being supported and guided by a frame of the machine, the presser conveyor is supported and guided by a chassis adjustable in height above the frame. It follows from this arrangement that the machine can admit containers of any height within reasonable limits and that the pressure exerted by the pressure conveyor can be finely adjusted.

Preferably finally in the aforementioned conveyors are "belts" made up of pallets articulated one on the other in the manner of chain links and the stoppering and / or herrnoscellage members mentioned above are detachably fixed on said pallets. Still according to the present invention, a method of thermosealing a cover on a container, said method being of the kind with high frequency induction according to which an alternating magnetic field induces, in electrically conductive parts of the cover and / or of the neck of the container, electric currents which cause, by Joule effect, heating of said metal parts, said magnetic field being produced by an inductive loop conductor, is mainly characterized, in that said container is movable relative to the inductor, and in what is interposed between the inductor and said metal parts of the cover or container an electrically conductive piece, called focusing relay, said relay accompanying the container in its relative movement, said relay being intended to intercept a large flow from the inductor in order to restore in the vicinity of said metal parts a flow substantially equal to the flow intercepted.

In the general case of implementation of the method and in order to achieve the desired goal, the inductor is fixed relative to a machine frame, itself fixed relative to the ground and consequently it is the containers which are mobile compared to the machine frame which is thus defined as a heat transfer and possibly capping transfer machine. It will be noted that the method as defined above in its generality is applicable both to a circular transfer machine and to a linear transfer machine as described above and that it is entirely suitable for the latter type of high rate machine transfer. . According to what is said above and so that the duration of induction is sufficient, it is necessary that said inductor extends over a certain part, called heating zone, of the path of the containers; it is also necessary that the cover is kept under pressure during its passage through the heating zone and then consecutively during its passage through a so-called cooling zone; practically the length, on the path of the containers, of the cooling zone will be equal to at least three times the length of the heating zone. Still according to the present invention, the aforementioned focusing relay consists, in the generality of its design, of two electrically conductive loops forming a single circuit, the first so-called interception loop, delimiting a fairly large surface, being intended to intercept part of the flow of the inductor to generate an intense current in the circuit, the second so-called restitution loop, delimiting an area substantially identical to the section of the neck of the container, being intended to restore, under the effect of said current, a significant flow in the vicinity of said pass.

According to a preferred embodiment for the simplicity of its execution, for its energy efficiency and for its possibilities of use, said focusing relay is a metal crown, of copper for example, split on a radius to interrupt the continuity of the crown; thus the first loop is constituted by the outer edge of a metal crown, or circle hollowed out in its center, the second loop is constituted by the inner edge of the crown, or of the central recess, the first and second loops being connected to constitute a single circuit by the edges of a cut interrupting the continuity of the crown. Preferably the edge of said central recess intended to be opposite the container to be capped, is shaped as a shoulder so as to be able to simultaneously press on the cover and surround the upper edge of the neck.

Preferably, the focusing relays are removably mounted on the capping machines, by means of a support piece on which they are permanently fixed; this part, as well as the organs' of the machine which supports it, is made of non-conductive material.

The present invention in its various aspects will be better understood and details will be apparent from the descriptions which will be made in relation to the figures of the appended plates in which:

Fig. 1 is a schematic representation seen from above of a linear capping machine and / or heat sealing according to the invention,

Fig.2 is an elevation of the same, Fig.3 is a more detailed illustration of an input section of a machine from the previous figures,

Fig.4 is a schematic illustration of the implementation of the method according to the invention,

Fig.5 is a plan view of an embodiment of a focusing relay and its support part, implemented in the method of the previous figure,

Fig.6 is a section of the same, Fig.7 is a partial schematic illustration in plan of the implementation of the method of Fig.4 by means of a linear transfer machine, Fig.8 is a schematic illustration partial plan of the implementation of the method of FIG. 4 by means of a circular transfer machine, and

Fig.8bis is a section along AA of the previous figure. In Figs. 1 and 2 the capping and / or sealing of containers such as bottles 1 is carried out by means of a linear transfer machine which essentially consists of two endless conveyors 2 and 3 delimiting in height a transport corridor 4 or circulation of containers; the conveyor 2, said carrier, is supported and guided by means of slides for example, by a frame 5 of the machine; this conveyor, according to this structure, is driven by pinions, drums, or other members such as 6.

The conveyor 3, said presser, is supported by a chassis 7 adjustable in height above the chassis 5; the height adjustment is preferably obtained by moving the chassis 7 along rails or vertical guide columns 8 and 9 by means of vertical screws driven in rotation by a common shaft and angle return gears; this movement mechanism is not shown in the figures.

I1 should be understood that the opposite faces of the conveyors are guided, for example by sliding, so that they remain rigid and parallel. The pressure conveyor 3 has an entry section 10 inclined upwards in a gentle slope, so that the support of the conveyor on the containers is done progressively as they are introduced into the transfer corridor. 4 supported by conveyor 2.

The machine comprises, like the machines of the prior art, supply means 11 and discharge means 12, such as a carpet. It has at its inlet section a couple of superimposed screws 13 constituting an evenly distributed means of the containers on the carrier conveyor; however and in accordance with the invention, it takes advantage of the firm holding of the containers in the threads of its screws in order to use the inlet section of the machine as a station for fitting the plug by means of a distributor shown diagrammatically at 14. The pressure conveyor 3, the carrying conveyor 2 and the equiparticulating screws 13 are driven in synchronism, or alternatively isokinetic, with respect to the movement that each prints in the containers, by means of a variable speed drive group 18 and by means of transmission means shown schematically in 15 which can be chains as well as trees, insisting however on the positive character of these transmissions.

The transfer corridor 4 is divided into two sections: a section 16, called heating, adjacent to the inlet section, and a section 17, called cooling. When the machine of FIGS. 1 and 2 is used for heat sealing the respective lengths of sections 16 and 17 are such that they allow on the one hand the melting of the heat sealing material comprised between the cover and the edge of the container, and d on the other hand the resolidification of this material; these lengths also depend on the heating means used; if not example the heat is brought by conduction by means of a hot room, it will take more cooling time, therefore a greater length of the section 17 than if the rise in temperature results from the action of a field such as magnetic or electro-magnetic (microwave). It seems, according to the Applicant's experience, that the ratio of the lengths of sections 16 to 17 respectively, is at most equal to a third, or even that the length of the cooling section is at least three times the length of the heating section.

In FIG. 3, it appears more clearly, preferably, that the conveyor 3 is a belt made up of pallets such as 20 articulated to each other in the manner of chain spindles, a pair of notched wheels 21, called input wheels, anchor in the hinge pins 22 of the pallets and ensure a positive drive of the belt; there is a slide 23 on the lower edge of the chassis 7 made of a material such as Teflon with a low coefficient of friction; the slide 23 is intended to constitute a firm support for the pallets 20. The pallets 20 have a length equal to a fraction of the pitch of the screws 13 and some of them support a sealing and / or heat-sealing member, such as the organs 24.

There is shown in the figures a spout 25 of the dispenser 14 of the previous figure; it appears that during their progression the necks of the receptacles extract from the spout 25 the capsules such as 26 which can incorporate the heat-sealable seal.

We also note in fig.3 that the frame 7 may include a recess 27 intended to constitute a housing for heating means.

It also appears in fig. 3 that the slope of the entry section of the pressure conveyor is about fifteen degrees and that the connection of this entry section with the straight section is made in a rounded 28 d 'fairly large radius.

Finally, it should be noted that the design of a machine as described above does not determine the choice of the type of closure, which can be either a simple encapsulation, a heat seal by a seal, than the two, no more than it does not determine in the case where the heat sealing is used, the heating means used for this heat sealing; however, it should be noted that it is particularly suitable for the heat-sealing process which will be described with the aid of the following figures.

In fig.4 and in order to illustrate the process of thermosceliage of the invention, there is shown a container 30 circulating below an induction loop 31; the container 30, bottle in this case, is supported by a plate 32 while a plate 33 compresses by means of a split metal crown 34 a capsule 35 on the neck of the container.

The loop 31 is constituted by a hollow tube made of electrically conductive metal such as copper; the hollow tube is supplied with high frequency alternating current, for example two megahertz; the passage of current in the loop produces a magnetic field of identical frequency; this field at a given time can be represented by the arrows 36; it will be noted that the technology of such induction loops, as well as their means of supply, is well known in itself. The method of the invention consists in circulating in the magnetic field produced by the loop the crown 34 bearing on the plug. The crown 34 has a conformation which will be described later and which allows it to act as a relay concentrating the magnetic flux picked up by its entire surface, in its central recess; the crown is therefore called the focusing relay. It appears that, thanks to the use of this relay, a sufficient magnetic flux can be supplied to the metallic parts incorporated either in the lid, or in an overcap, or in the neck of the bottle itself, while leaving the fixed induction loop; this last characteristic has two very appreciable consequences on the economy of the machine, in the first place the design of this one is considerably simplified and in the second place its rates of work are considerably increased.

On fig.5 and 6 we note that as has already been said the focusing relay is a metal ring 34 split at 37; therefore the periphery 38 of the crown constitutes a conductive loop in which the variable magnetic flux induces a current; this current is all the stronger for a given field and frequency the larger the diameter of the crown. The induced current is transmitted in the loop 39 constituted by the edge of the central recess 40, by the slot edges 41 and 42; the periphery 38 of the crown constitutes an interception loop while the periphery 39 of the central recess constitutes a restitution loop. As can be seen in fig.5 the edge of the recess 39 is shaped as a shoulder 41 to cap the capsule 35 and allow it to exert pressure while making the loop 39 as close as possible to the metal parts included under the capsule.

Preferably split crowns, such as 34, are permanently mounted on supports 43 which are themselves provided with adaptation means on the corking machine.

The capping transfer machines allowing the implementation of the process described above will advantageously be of one of two types, with linear transfer or with circular transfer.

In FIG. 7 which schematically illustrates part of the induction or heating zone, the machine is a linear transfer machine similar to that of FIGS. 1 to 3. The induction loop 50 has a median axis 51 along the following lines the straight path of the focusing relays such as 52; the relay relays 52 are mounted on pallets 53 hinged to each other in the manner of chain links, as was said for the machine of Figures 1 to 3; in the machine of these figures, the housing 27 made in the chassis 7 can be used to house the inductor 50.

In fig.8 similar to what is shown in fig.7 the machine is a circular transfer capping machine; it will mainly be noted that the median axis 55 of the induction loop 56 is curved to follow the circular path of the focusing relays 57; on this machine as on the previous one the inductor is fixed relative to the frame of the machine.

In fig.δbis is shown in elevation and in section a plugging element mounted on a column 58 with vertical movement, the element comprising the relay 57 and a support 59 entering the heating zone below the inductor 56. Although embodiments of the present invention have been shown more or less schematically in order to illustrate them, it should be understood that the scope of the invention is not limited to these above-mentioned forms. described but that it is understood to mean any sealing or heat sealing machine or process defined by the claims which follow.

Claims

PATENT CLAIMS

1.- Method of thermosealing a cover on a container, said process being of the high frequency induction type according to which an alternating magnetic field induces, in electrically conductive parts of the cover and / or of the neck of the container, electric currents which cause, by Joule effect, a heating of said metal parts, said magnetic field being produced by a loop conductor called inductor, characterized:

- in that said container is movable relative to the inductor, and

- in that there is interposed between the inductor and said metal parts of the cover or container an electrically conductive part, called a focusing relay, said relay accompanying the container in its relative movement, said relay being intended to intercept a large flow from the inductor eh to restore in the vicinity of said metal parts a flow substantially equal to the intercepted flow;

2.- Method according to claim 1, characterized: in that said inductor is fixed with respect to a machine frame itself fixed relative to the ground, and in that, consequently, it is the containers which are movable by relationship to the building;

3. - Method according to claim 1, characterized: in that said inductor extends over a certain part, called heating zone, of the path of the containers;

4.- Method according to claim 3, characterized: in that the cover is kept under pressure during its passage through the heating zone and then consecutively during its passage through a so-called cooling zone;

5.- Device for implementing a method according to claim 1, characterized: in that said focusing relay comprises two electrically conductive loops forming a single circuit, the first so-called interception loop, delimiting a surface fairly extensive, being intended to intercept part of the flow of the inductor to generate an intense current in the circuit, the second so-called restitution loop, delimiting an area substantially identical to the section of the neck of the container, being intended to restore, under the effect of said current a large flow in the vicinity of said neck;

6.- Device according to claim 5, characterized:

- in that said first loop is constituted by the outer edge of a metal crown, or circle hollowed out at its center,

- in that said second loop is constituted by the inner edge of the crown, or of the central recess, and - in that the first and second loops are connected to constitute a single and same circuit by the edges of a cutout interrupting the continuity of the crown;

7.- Device according to claim 6, characterized: in that the edge of said central recess is shaped as a shoulder so as to be able to simultaneously press on the cover and surround the upper edge of the neck;

8.- Automatic machine for capping and / or heat sealing a container by means of a cover and / or a capsule, characterized: in that it comprises for cooperation:

a first so-called lower or still carrier conveyor on which the containers are placed, said carrier conveyor being rectilinear on at least part of its path, - a second so-called upper conveyor or presser, said second conveyor being, on part of its path, straight and substantially parallel to said straight portion of the first conveyor and being located above it at a distance very slightly less than the height clogged containers, said second conveyor having an upwardly inclined entry section with a gentle slope, said second conveyor supporting equidistant sealing and / or sealing units, - motor and transmission means for isokinetically animating said first and second conveyors;

9. - Machine according to claim 8, characterized: in that it comprises at its inlet section at least one screw constituting an evenly distributed means of the containers on the carrier conveyor, said screw being driven in synchronism with said conveyors;

10.- Machine according to claim 9, characterized: in that the carrier conveyor being supported and guided by a frame of the machine, the pressure conveyor is supported and guided by a frame adjustable in height above the frame;

11. Machine according to claim 10, characterized:

- in that said conveyors are belts consisting of pallets articulated one on the other in the manner of chain links, and

- In that said sealing and / or heat-sealing members are fixed araovile on said pallets.