Method and apparatus for manufacturing a container filled with a product.

TECHNICAL FIELD: The present invention relates to a method and apparatus for manufacturing a container filled with a product according to the preambles of claims 1 and 8 respectively.

BACKGROUND:

Tubes and bottles made from thin-walled plastic or plastic laminated material are used for packaging of, for example, creams, ointments and various other viscous chemical/engineering preparations. Swedish Patent Application 8800548-3 describes an end-piece and a method for manufacturing tubes or bottles by butt-welding an end-piece in both ends of a tubular-shaped body portion of thin-walled plastic or laminated plastic material.

The advantage of manufacturing tubes or bottles in this way is that the need to transport bulky empty containers over long distances is avoided. Accordingly the method allows the private packager to produce his own tubes or bottles without comprehensive eguipment.

The tube or bottle produced according to the above method can be filled with its product via its opening, after which a cap is affixed over the opening with the aid of, for example, screw threads.

In many cases, however, it is desirable to provide a container which has been sealed in a controlled

environment so that the customer can confirm that the packaging is unopened. This results in enhanced quality, both for the packaging and its contents.

During production of such a sealed container it is advantageous that filling with the product occurs between the fitting of the first end-piece, preferably tubularly formed, and the second end-piece.

In the method according to said Swedish Patent Application 8800548.3 tubular-shaped body portions are located on a rotary indexing table for movement between various stations. At one station each end-piece is introduced into the upper end of a corresponding body portion by a piston to an intermediate position where it partially projects into the body portion. This partially assembled work piece is then moved to the next station where heating energy is supplied to the circumferential end region of the tube and intersecting region of the end piece. Once a temperature is attained at which the material is sufficiently soft, the work piece is advanced to the subsequent station where a piston is reapplied to push the end piece to its terminal position. Rapid cooling of the welding site is then achieved by means of passages within the piston for a cooling fluid.

Up until recently it has proved impossible to apply the end-piece with the piston in situ during heating since the rim of the end-piece upon which the piston acts is subjected to heating to between 300 ^* C - 500 ^* C, thereby softening the material and causing it to adhere to the piston.

A partial solution to this problem is described in PCT/SE/91/00124 claiming priority from SE 9001086-9, filed 26 March, 1990, both of which were published after

the filing date of the present application. Said documents relate to a method and a device for controlling the temperature of a container end portion during manufacture. An end-piece is placed in a defined intermediate position where it partially projects into the open end of a tubular body. Warm gas is supplied to the body portion end region and the end of the outwardly projecting portion of the end piece in order to soften the material in these portions. The end-piece is then pushed to its terminal position in the tubular body at the same time that a cooling gas is supplied to the transverse wall of the end-piece, thereby preventing the pushing means adhering to the transverse wall.

The object of the present invention is to provide an improved method and apparatus which permits the production of filled containers at a high rate in a one- step operation.

This object is achieved according to the invention by a method according to claim 1 and an apparatus according to claim 8.

Preferred methods and embodiments of the apparatus according to the invention are given in the respective dependent claims.

Since, according to the invention, the abutment means acts on the transverse wall of the end-piece which is not subjected to direct heating, and the abutment means is cooled, there is no tendency for the abutment means to adhere to the end-piece.

Cooling of an abutment means is known per se from SE-A- 8704048-1. In this document, however, the container is in the form of a plastics bowl which is then provided with a

sealing membrane. The sealing membrane is held on the abutment plate by means of suction and is lowered until the outer circumferential region of the membrane contacts the rim of the bowl. A circumferential electrical heating ring then contacts the membrane to effect heat-sealing of the membrane to the rim of the bowl. Due to the localized heating, the rest of the membrane is substantially unaffected by the heating operation. The abutment plate is provided with cooling means, not to prevent it adhering to the membrane but to help maintain the shape of the membrane which is affected by the heat radiating from the product within the container.

BRIEF DESCRIPTION OF THE DRAWINGS: The invention will be described in more detail in the following, with reference to the drawings in which

Figures 1 and 2 schematically show the application of an end-piece to a tubular body portion in two steps with apparatus according to one embodiment of the present invention, and

Figures 3 and 4 schematically show the application of an end-piece to a tubular body portion in two steps with apparatus according to a second embodiment of the present invention.

BEST MODE OF CARRYING OUT THE INVENTION:

The flattenable tubular body portion 10 shown in the drawings can be made from a single-layer plastic material or from a laminate comprising a metal foil which provides the body portion with better barrier properties. The body portion can be produced by a foil butt-seam welder or, alternatively, from an extruded tube, cut to the appropriate length. Such body portions normally have a wall thickness well under 1 mm.

In the drawings only the upper end of the body portion is shown. The lower part of the body portion is already fitted with an end-piece in the form of, for example, a discharge outlet with cooperating screw cap. The body portion is filled via its open end with a product 11 to a predetermined level which corresponds to the desired quantity for the container. The body portion is now placed vertically with the opening upwards in a (not shown) cylindrical holder in a rotary indexing table which is provided with means for fitting the end-piece in the following sequence of steps.

In Figures 1 and 3 the upper end-piece 13 has been partially introduced into the upwardly open body portion end and then advanced one stage to the welding station shown in Figures 1 to 4.

A suitable end-piece 13 is that which is described and claimed in PCT/SE91/00121 which was published after the filing date of the present application. This end-piece comprises a sleeve-like insert section 14 which, on the inner end, is provided with a transverse wall 15 and, on the other end, is provided by a U-shaped section 16. The insert section 14 tapers inwardly towards the transverse wall 15. The U-shaped section is provided with a groove that tapers towards the bottom of the U-shaped section.

The end-piece can, by way of example, be produced by injection-molding, whereby a barrier foil blank may be included on the inner side or the outer side of the transverse wall 15.

The welding station is provided with passages for supplying hot gas via directed openings 17 to the region of the body portion end edge and to the groove in the U- shaped section 16 in order to soften these regions by

application of heat to a temperature between about 300 - 500 ^β C. After suitable heating, the holder is displaced upwardly in the welding apparatus so that the end-piece 13 is pressed into the tubular body portion until the rim of the body portion meets with the bottom of the groove, as shown in Figs. 2 and 4. A central abutment member 18 of slightly smaller diameter than the transverse wall 15 serves as an abutment for the end-piece 13.

The abutment member 18 comprises a central stem portion 19 which merges into a transverse disc portion 20 generally parallel to the transverse wall 15 of the end- piece 13. The disc portion presents a diameter which is slightly less than the inner diameter of the sleeve-like insert section 14 of the end-piece such that the disc portion can be accomodated within the insert section 14. The disc portion is provided with a downwardly directed flange portion 21 around its circumference, with the end 22 of the flange portion 21 remote from the disc portion serving as the abutment surface of the abutment member 18. The depth of the flange portion 21 is chosen such that, in the abutting position shown in the drawings, an evacuation cavity 23 is created which is delimited on its lower side by the transverse wall 15 of the end-piece 13, on its upper side by the disc portion 20 of the abutment member 18 and circumferentially by the flange portion 21.

In the embodiment shown in Figs. 1 and 2, the entire abutment member is made from the same material, for example a suitable metal. To reduce the tendency of the abutment member to stick to the transverse wall 15 of the end-piece during the heating and insertion process, the contact surface 22 of the flange portion 21 may be coated with a non-stick material such as TEFLON.

In the embodiment shown in Figs. 3 and 4, the flange portion 21 of the abutment member 18 is made from a material different from the rest of the abutment member. This material is suitably a ceramic which may also be coated with a non-stick layer.

The purpose of the cavity 23 will now be explained. In a preferred embodiment according to the invention, the transverse wall of the end-piece 13 is provided with an evacuation nipple 24 to permit the evacuation of air from the head-space between the product 11 and the transverse wall 15 when the end-piece is pressed into the body portion end. Accordingly, the evacuation cavity 23 is in communication via at least one through hole 25 in the disc portion 20 with a vacuum source arranged to create a region of lower pressure around the stem portion 19 of the abutment member 18.

In accordance with the invention, the abutment member is provided with cooling means to prevent the abutment surface 22 adhering to the transverse wall 15 of the end- piece. In the embodinment shown in Figs. 1 and 2, the stem portion 19 of the abutment member 18 is provided with a conduit 26 for the supply of a cooling medium and a conduit 27 for the removal of the cooling medium. Of course, these two conduits can be formed as one continuous conduit. A suitable cooling medium may be water.

In the embodiment shown in Figs. 3 and 4, the cooling medium is in the form of a gas, for example air, which passes along a supply conduit 26 in the stem portion 19 of the abutment member 18. The gas then flows through several radially extending cooling passages 28 in the disc portion 20 of the abutment member. The cooling gas then exits the abutment member via slots or nozzles 29

arranged circumferentially around the intersection of the disc portion 20 with the flange portion 21. The cooling gas can then mix with the air evacuated from the head- space within the container (should evacuation be chosen) and is accordingly removed via the previously mentioned vacuum source.

Once the end-piece has been heated and pushed to its terminal position within the tubular body portion, the U- shaped section 16 is compressed whilst still soft so that a seal in this region is achieved. This is performed at a subsequent station on the rotary index table and can be carried out by a vertically displaceable abutment and a plurality of horizontal compression devices. These compression devices may be mechanically or elastic- hydraulically operable. Furthermore, the evacuation nipple 24 is heat-sealed so as to form a closed nipple.

The invention is not restricted to the above described embodiments, but may be modified within the scope of the appended claims. For example, the transverse disc portion 20 of the abutment member need not be parallel to the transverse wall 15 of the end-piece 13, but instead can form an acute angle therewith.