WO2001040072A1

WO2001040072A1 - Device for sealing the front edge of the neck of a container

Info

Publication number: WO2001040072A1
Application number: PCT/EP2000/011623
Authority: WO
Inventors: Udo Jandewerth; Hans-Peter Kabisch
Original assignee: Tetra Laval Holdings & Finance S.A.
Priority date: 1999-12-01
Filing date: 2000-11-22
Publication date: 2001-06-07
Also published as: AU2508101A; DE19957744A1

Abstract

Disclosed is a device for sealing the front edge of a neck (2) of a container (1) used for pouring purposes and made of plastic during the treatment of the inside surface (7) of said container (1). In order to enable the surface of the front edge of the neck (2) to remain untreated or devoid of any effect thereof using simple means, even when there is a difference in pressure during the treatment of the inside surface (7) of the container (1), a cover ring (5a) made of an elastic material with a cone-shaped (or optionally flat) sealing lip is maintained by a receiving element (6) arranged in a coaxial position thereto in such a way that the front edge can be pressed against the sealing lip with deformation thereof.

Description

Device for sealing the front edge of a container neck

The invention relates to a device for sealing the front edge of a pouring neck made of plastic of a container during a treatment process of the inner surface of the container.

Containers with a pouring neck made of plastic are known. The neck has an external thread on which a cap can be screwed. There are also containers of this type packed with sterile goods, in which, in order to maintain sterility inside the container, a plastic-coated aluminum foil is welded onto the front edge of the pouring shark and seals the container opening. The plastic cap is then screwed over this, which results in adequate mechanical protection for this film.

To improve the barrier properties, it is also known to coat containers inside or outside with a layer, the coating process being carried out with the aid of a plasma. This chemical process, which takes place in a treatment chamber, enables, for example, an application from the gas phase (CVD, Chemical Vapor Deposition). A process gas, for example a mixture of an organosilicon compound, an oxidizing agent and a carrier gas such as argon, is introduced into the completely plastic container, for example a PET bottle. Electromagnetic energy is radiated in and ignites the plasma inside the container. In this treatment process, a glass-like silicon oxide is applied to those parts of the interior of the container which are exposed to the burning plasma.

After filling the coated plastic containers, for example with liquid food, the containers must be sealed. This is done in the usual way by sealing an aluminum foil coated with plastic onto the front edge of the pouring neck. However, if this front edge is coated with the glass-like silicon oxide layer, the conventional heat sealing of the aluminum foils is not possible because the melting point of the glass is much higher than that of the plastic.

In the coating process described above, but possibly also in other treatment processes, the surface of the front edge on the pouring Keep the neck free of treatment and preferably coating, so that it is possible to seal the plastic-coated aluminum foil, especially when packaging food in a sterile manner. In many applications where liquid food is to be packed in the containers described here, the sealing effect of a screw cap, as in the case of a mineral water bottle, is not sufficient.

The invention is therefore based on the object of creating a device of the type mentioned at the outset, with the aid of which the front edge of the pouring neck remains on its surface with no simple treatment or interference, even if one of the inner surfaces of the container is being treated during treatment There is a pressure difference between the inside and outside of the container.

This object is achieved in that a cover ring made of elastic material with a conical or planar sealing lip is held by a ring receptacle arranged coaxially to the latter such that the end edge can be pressed against the sealing lip while deforming it. The sealing device is given a ring shape because treatment and in particular coating materials have to be transported into the interior of the container. The sealing device must therefore have an opening through which these materials are transported. It is advisable to use the annular end edge of the pouring neck for sealing simply by pressing the end edge against an appropriately designed sealing lip. It is advantageous if the sealing lip has the shape of a truncated cone or a cone, the cover ring with the sealing lip should be made of elastic material. If, for example, the main devices and feed devices for coating or treatment materials are arranged below the ring receptacle, it is advisable for the arrangement of the sealing device according to the invention to arrange the container with its pouring neck downward, facing the ring receptacle, in such a way that the leading edge can be pressed against the sealing lip located above the ring seat. The elastic material favors the deformation of the sealing lip and this in turn flawless sealing function between the space inside the pouring neck and thus also the container on the one hand and the environment outside the container and outside the ring receptacle on the other. It can be imagined that, relative to the ring holder on the tool side, an upper holder for the container is provided, with the result that this drive ensures that the end edge is pressed against the sealing lip. With sufficient pressure, not only does the sealing along the round edge of the rim take place, but also the deformation of the sealing lip, which is lifted again after the treatment process has been completed and the pressure has been released. The elastic material of the cover ring allows the cover ring to be deformed by pressing it on over many operating cycles with a long service life. As a result of this pressing and deforming of the sealing lip, it lies on the front edge of the pouring neck in such a way that it remains without treatment or interference and also with coating processes. remains uncoated. If afterwards the usual sealing of a film is desired, then this is easily possible, contrary to the previously known problems.

Due to the sealing function due to the pressing of the front edge onto the sealing lip, it is also possible to choose the pressure inside the container before, during or after the treatment differently than outside the container.

The containers considered here include packaging made of coated paper, cardboard or plastic. These can be plastic bottles in which the bottle neck is made in one piece with the main body from plastic. However, such containers are also conceivable, which partly consist of paper, in which partly the main body comprises paper or a similar material, and which nevertheless have a pouring neck made of plastic.

It is advantageous if, according to the invention, the elastic material of the cover ring is rubber, rubber, preferably neoprene rubber, silicone rubber or natural rubber. Rubbers are highly polymeric, predominantly elastic substances, which include the natural rubbers, silicone rubbers mentioned, but also polyurethane rubbers and the like. Rubber is generally understood to mean the unvulcanized raw product, while rubber means the fully vulcanized product. It is known that natural rubber is obtained from the white, milky juice (latex) that flows out of the trunks of the milkweed after scoring. A cheap neoprene rubber is known under the trade name Viton. These are heat and chemical resistant vulcanizable fluoroelastomers based on vinylidene fluoride-hexafluoropropylene copolymers that can be used as seals.

The sealing device according to the invention is preferably characterized in that the cover ring has a lower support part which is delimited by an approximately cylindrical jacket-shaped radially inner and radially outer surface and the sealing lip fastened to the latter. It is expedient to note the diameter of the holes, for example the free edge of the sealing lip or the inner hole in the support part. For some treatment processes, for example the coating process described at the outset, these mostly circular-disk-shaped holes have to be as large as possible in order to lead the process gas through the inner holes or to remove the used process gas again after the coating.

The lower support part serves to support and hold the cover ring, while the outer surface of the sealing lip ultimately forms the functional sealing surface which, together with the front edge of the pouring neck, ensures the function of the sealing device. For a particularly favorable mounting, the support part is provided by a radially inner and a radially outer surface limited, which are approximately cylindrical in a special and preferred embodiment. In such an embodiment, the support part can be arranged and fastened to a ring receptacle that is easy to manufacture.

While it is quite conceivable to allow the cone of the sealing lip to expand outwards, i.e. facing away from the central axis of the cover ring, it has been found in this embodiment that minimum pressures are required for a good covering of the front edge of the pouring neck, namely the Bend the sealing lip from the frusto-conical inclined position in relation to the imaginary horizontal plane in the lower support part into a parallel and also horizontal plane. Before bending the first time the front edge touches the sealing lip, only the outer edge of the front edge is in contact with the sealing lip, while the majority of the horizontal, annular surface of the front edge is still connected to the interior of the pouring neck and the container. If this interior is filled with coating gases, they can settle on the front edge. Only a higher pressure of the front edge against the sealing lip and only a sufficient deformation of the sealing lip then ensure that the front edge is completely covered, so that it is not influenced during the treatment process. There are some applications in which the sealing lip is not sufficiently deformed.

These special cases can also be surprisingly mastered by the invention in that the axially higher part of the frustoconical sealing lip faces the central axis of the cover ring. The axially higher part of the sealing lip is the part facing away from the lower support part, in which the free edge of the sealing lip lies. The above-mentioned hole, a through-hole for process gas, will also be located in this. This through hole should be as large as possible to favor the treatment processes. The advantage of this embodiment with the “inward” sealing lip has the advantage over the outwardly widening sealing lip that before the bending of the sealing lip the first time the front edge is touched, not the outer but the inner edge of the front edge first comes into contact with the sealing lip The predominant horizontal part of the flat front edge is therefore also before the sealing lip is deformed outside this contact line between the front edge and the sealing line and thus outside the sealing line, which becomes a sealing surface after the bending and shaping the interior of the pouring neck in connection, so that a coating of the front edge is excluded in this embodiment with even greater certainty and under almost all circumstances.

It is advantageous if the diameter of the passage hole at the free end of the sealing lip is less than or equal to the inside diameter of the support part, because then the gas supply and gas discharge mechanics are optimally radio-active when gases are passed through the cover ring. tioniert. In preferred embodiments, the difference in diameter is between 1 and 3 mm.

In the other embodiment, in which the cone of the sealing lip widens outwards, the situation is reversed. In this case, the design requires that the diameter of the passage hole at the free end of the sealing lip is not only larger than the inner diameter of the support part, but even larger or approximately equal to the outer diameter of the cover ring. In this embodiment, the inside diameter of the support part specifies the minimum passage cross section for the gases to be transported.

In an advantageous further embodiment of the invention, the outer diameter of the cover ring is x mm larger than the outer diameter of the pouring neck of the container, with 2 <x <10 and preferably 3 <x <7. If the person skilled in the art observes this teaching, he will determine that this Sealing the end edge on the container neck is possible with particularly simple means and not only tolerances of one type of container neck, but even different types of pouring necks with different diameters can be assigned to the same cover ring. In other words, a sufficient length (as seen in cross section) of the sealing lip is then available in the radial direction to the respective end edge, so that larger and smaller necks (within a certain bandwidth) can be pressed against one and the same cover ring. This simplifies the sealing device considerably, because one and the same ring holder with cover ring (in a certain bandwidth) can be associated with different types of containers.

If, according to the invention, an annular groove is arranged between the support part and the sealing lip of the cover ring, the hardness can be increased for selected materials for the cover ring, because then there is a free space between the underside of the sealing lip and the support part, into which the sealing lip can move more easily and can deform more easily.

Furthermore, the device according to the invention is characterized in that the surface of the sealing lip forming the functional sealing surface is so smooth and soft that injuries to the end edge of the pouring neck are excluded. Although the sealing function according to the invention would not be impaired in the case of insufficiently smooth and soft configurations of the surface in question, if there are grooves, notches or grooves on the flat end edge of the neck of the container, its sterile closure is achieved by sealing the plastic-coated aluminum foil not always properly guaranteed with the consequence of leaks and non-sterility. It is also advantageous if a bellows is attached between the support part of the cover ring and the sealing lip. It has been found that in this embodiment the functional sealing surface is separated from the support part of the cover ring during operation. The bellows serves as a resilient part of this separation. It can preferably be a one-piece bellows, in which, with regard to the shape, two frustoconical surfaces are set against one another and connected to one another or these truncated cones are integrally formed with one another in such a way that the sealing surface is located on the respective narrower end on one side , while opposite the support part is attached or molded in one piece. In the embodiment described first, the sealing lip and thus the functional sealing surface on the outside was deformed at the top by reducing the height of the entire cover ring. In the case of the further embodiment described last, the functional sealing surface no longer needs to be deformed and does not need to spring. Rather, the sealing lip in the last-mentioned embodiment can be provided in a plane, if necessary shaped, the plane through this sealing lip being at a distance and parallel to that, in general horizontal plane, which is to be thought of as being laid by the supporting part. Regardless of the movement of the now flat sealing lip, the flat supporting part can remain in its position with respect to the ring receptacle, even if the plane were tilted in the sealing lip.

There is also the advantage that, in the case of the bellows embodiment, any fold formation when the front edge of the container neck is pressed against the cover ring and against the ring receptacle is absorbed by the bellows alone. In the above-mentioned embodiment with the inwardly and upwardly narrowing, frustoconical sealing lip, small folds would have to be absorbed by the deformed sealing tip in the case of very strong pressings and deformations. The sealing function can be compensated for by the corresponding softness of the sealing ring, but less constraints need to be taken into account in the version with the bellows in order to solve the task perfectly.

Finally, in the bellows embodiment, a radially larger width of the functional sealing surface can also be achieved because, for the reasons mentioned, greater demands can be placed on it. This in turn allows you to control a larger diameter range for different end edges with one and the same cover ring. This has the advantage that fewer changeover processes will occur on average, since a larger number of differently shaped pouring necks can be processed with the same cover ring.

In all embodiments, it is possible to compensate for small angular deviations of the longitudinal central axis of the respective container or its pouring neck on the one hand and the central axis of the ring receptacle and the cover ring on the other hand. With the cover rings according to the invention, the diameter of the container with the large Seal the pouring necks of 38 mm, with smaller pouring necks of 28 mm and those with even smaller diameters, which are intended for crown caps. The simple construction of the sealing device according to the invention has a large span.

The sealing device according to the invention reliably and completely prevents the coating of the end edge, which later forms a sealing and sealing surface and surrounds the edge of the pouring neck. Without complex mechanics, the front edge can be covered well with technically simple means. The sealing effect and the operation of the device according to the invention are ensured both at normal pressure and under vacuum, since no cavities or open structures are required which would prevent the formation of a vacuum. Even the process of plasma deposition and coating of hollow bodies on the inside is possible with the new device, because it can be constructed to be chemically robust with light means. Due to the relatively soft cover ring, no metal parts come into contact with the front edge of the pouring neck, which is thus protected from injuries and later leaks.

Silicone rubber in particular has proven to be cheap because it is chemically stable and nevertheless provides a soft and elastic cover ring.

The changeover when processing other types of pouring necks or containers is achieved very easily and quickly by the new ring holder according to the invention. In all the embodiments described here, it is expedient that the invention is further embodied in that the cover ring can be supported radially by a collar and axially by an annular shoulder of the ring receptacle. In the first-mentioned embodiment, in which the truncated cone of the sealing lip widens outwards and upwards, the supporting part lies on the outside around the collar of the ring seat and is thereby supported radially securely, while this is ensured axially by the ring shoulder of the ring seat. In the other embodiment with the truncated cone-shaped sealing lip which widens upwards and inwards, the cover ring lies within the collar of the ring receptacle. As a result, the deformation of the cover ring is particularly favored when the end edge is pressed against the cover ring. This gripping of the collar of the ring receptacle also represents the optimal support for the embodiment with the bellows.

Further advantages, features and possible applications of the present invention result from the following description of preferred embodiments with reference to the attached drawings. These show:

FIG. 1 shows in cross section a container directed downwards against a sealing device with the pouring neck, with the ring receptacle shown below, 2 shows a perspective side view of the structure of FIG. 1 at an angle from above,

FIG. 3 shows a partial representation broken away in cross section according to detail III in FIG. 1,

FIG. 4 shows a cross-sectional view similar to FIG. 1, but with a different embodiment of the cover ring,

FIG. 5 shows a broken cross-sectional view of the detail designated V in FIG. 4,

Figure 6 is a similar representation as Figure 5, but with a cover ring without groove (other

Embodiment) is shown,

FIG. 7 shows the embodiment of the cover ring of FIGS. 4 and 5 in cross section without a ring seat,

FIG. 8 the cover ring of FIG. 7 in a perspective view obliquely from above,

Figure 9 in cross section another embodiment of a cover ring with bellows and

Figure 10 is a perspective view of the cover ring of Figure 9 obliquely from below.

The container 1 shown upside down in the figures has a pouring neck 2 opposite its bottom and shown here arranged below with an external thread, which is shown in a known manner and is not described in detail here. The pouring neck 2 is open at the bottom and is closed at its outer, open, lower end by an end edge 3 which lies in a plane which is assumed to be horizontal in the illustration of the drawings. The vertical longitudinal axis of the container 1, which coincides with the central axis 4 of a cover ring 5a, 5b, 5c, 5d, is to be considered perpendicular to this. The cover ring 5a .... 5d is held by a ring receptacle 6, which is attached to a ring plate shown here only by way of fastening screws. This ring plate, not designated, can also represent a main plate of a machine, in which, depending on the number of treatment stations, a corresponding number of holes are provided, which are of the same size and are arranged in alignment with the cylindrical passage in the ring seat 6. The inside diameter of the passage in the ring receptacle 6 is approximately as large and, on closer inspection here, for example somewhat smaller than the inside diameter of the pouring neck 2 of the respective container and specifies the passage cross section for fluid which is introduced into the interior of the container 1 from bottom to top and vice versa can be led out downwards, for example in the case of plasma coating the inner surface 7 of the container 1 being coated with a layer.

1 to 3 show a first embodiment of a cover ring 5a made of silicone rubber. This cover ring 5a has a conical or frusto-conical sealing lip 8a in the free, upper area facing the pouring neck 2 and a support part 9a, which is located in the opposite lower area facing the ring seat 6. Between the support part 9a and the sealing lip 8a of the cover ring 5a is a ring arranged groove 10a, which allows the sealing lip 8a to be deformed by the design of its undercut.

Not shown are a holding device for the pouring neck 2 and / or the container 1 and drive means to hold the container 1 with its pouring neck 2 in the vertical direction with respect to the stationary ring holder 6, i.e. to move in the direction of the central axis 4 such that the front edge 3 can be moved downwards in contact with the sealing lip 8a before the cover ring 5a is touched, as shown in FIG. 3; can then be moved further to the ring receptacle 6 in such a way that the sealing lip 8a is stretched, expanded and deformed from the obliquely positioned truncated cone surface in the direction of the horizontal until the entire front edge 3 is covered over the entire area by the sealing lip 8a; and vice versa vertically again away from the ring holder 6. This movement of the container 1 down to the ring receptacle 6 and back upwards applies to all embodiments.

In the figures 1 to 3 that state is shown where the front edge 3 has just got a ring line contact with the sealing lip 8a. Through the groove 10a, which in this embodiment is open radially outwards, the sealing lip 8a can be deformed against the cover ring 5a when the pressure of the end edge 3 is increased and finally bent into the horizontal.

In all embodiments, the cover ring 5 is supported radially by a collar 11 and axially by an annular shoulder 12 of the ring receptacle 6.

A second embodiment of a cover ring 5b is shown in FIGS. 4, 5, 7 and 8. This again has the support part 9b in its lower area and the sealing lip 8b in its upper area, which is also frustoconical here, but narrows upwards towards the central axis 4 of the cover ring 5b.

In this and in the other embodiments, the support part 9b has an approximately cylindrical outer radial inner surface 13 and a radially outer surface 14. These limit the respective support part 9a to 9d.

The upper, outer surface 15 of the respective sealing lip lies on the end of the cover ring 5a to 5d diametrically opposite (in the direction of the central axis 4) and represents the functional sealing surface 15. This surface of the sealing lip which forms the sealing surface 15 8a to 8d is smooth, and the material of the cover ring 5a to 5d is so soft that injuries to the front edge 3 of the pouring neck 2 are excluded in all embodiments of containers 1. The embodiment of Figures 4, 5, 7 and 8 of the cover ring 5b differs from that of the cover ring 5c of Figure 6 only in that the cover ring 5b has an annular groove 10b between the sealing lip 8b and the support member 9b, while this annular groove in the embodiment of the cover ring 5c of FIG. 6 is eliminated. As a result, the radial distance between the inner surface 13 and the outer surface 14 of the support part 9c can be made smaller. With a correspondingly soft material of the cover ring 5c, the sealing lip 8c can also be deformed in the desired manner here. The embodiment with the bellows 16 is shown in FIGS. 9 and 10. The cover ring 5d is formed here from two frustoconical parts, which are set against one another in the manner particularly shown in FIG. 9 in such a way that their narrow ends on one, lower side with the lower support part 9d or on the upper, other side with the sealing lip 8d lying essentially horizontally in one plane. The functional sealing surface 15 of the sealing lip 8d lies here in one plane, and due to the softness and flexible coupling of the support part 9d via the bellows 16, the sealing lip 8d can be moved and also set at an angle with respect to the support part 9d, which is to be considered stationary, without the slightest wrinkling would be feared on the sealing surface 15. In the embodiment of FIGS. 4 to 10, the diameter D _{3 of} the passage hole 17 at the free end of the sealing lip 8b, 8c or 8d is preferably less than or equal to the inner diameter D _{4 of} the support part 9b to 9d.

LIST OF REFERENCE NUMERALS:

1 container

2 pouring neck

3 forehead edge

4 Center axis of the cover ring

5a-d cover ring

6 ring holder

7 inner surface of the container

8a-d sealing lip

9a-d support part

10 ring groove

11 collar

12 ring shoulder

13 inner surface

14 outer surface

15 sealing surface

16 bellows

17 through hole

Dt outer diameter of the pouring neck

D ₂ outer diameter of the cover ring

D ₃ diameter of the through hole

D ₄ inner diameter of the support part

Claims

Patent claims

1. Device for sealing the front edge (3) on an existing plastic

Pouring neck (2) of a container (1) during a treatment process of the inner surface (7) of the container (1), characterized in that a cover ring (5a, 5b, 5c, 5d) made of elastic material with a conical (8a, 8b, 8c) or flat sealing lip (8d) is held by a ring receptacle (6) arranged coaxially to the latter such that the end edge (3) can be pressed against the sealing lip (8a - 8d) while deforming the same.

2. Device according to claim 1, characterized in that the elastic material of the

Cover ring (5a - 5d) is rubber, rubber, preferably neoprene rubber, silicone rubber or natural rubber.

3. Apparatus according to claim 1 or 2, characterized in that the cover ring (5a -

5d) has a lower support part (9a - 9d) delimited by an approximately cylindrical jacket-shaped radially inner (13) and radially outer (14) surface and the sealing lip (8a - 8d) attached to it.

4. Device according to one of claims 1 to 3, characterized in that the axially higher part of the frustoconical sealing lip (8b, 8c) of the central axis (4) of the cover ring (5b, 5c) faces.

5. Device according to one of claims 1 to 4, characterized in that the outer diameter (D ₂ ) of the cover ring (5b - 5d) is larger by x millimeters than the outer diameter (Di) of the pouring neck (2) of the container (1st ) with 2 <x <10 and preferably 3 ≤ x ≤ 7.

6. Device according to one of claims 1 to 5, characterized in that between the support part (9a, 9b, 9d) and the sealing lip (8a, 8b, 8d) of the cover ring (5a, 5b, 5d) an annular groove (10a, 10b , 10d) is arranged.

7. Device according to one of claims 1 to 6, characterized in that the functional sealing surface (15) forming surface (15) of the sealing lip (8a - 8d) is so smooth and soft that injuries to the front edge (3) of the pouring neck ( 2) are excluded.

8. Device according to one of claims 1 to 7, characterized in that a bellows (16) is attached between the support part (9d) of the sealing ring (5d) and the sealing lip (8d).

9. Device according to one of claims 1 to 8, characterized in that the cover ring (5a - 5d) can be supported radially by a collar (11) and axially by an annular shoulder (12) of the ring receptacle (6).