METHOD, END-PIECE AND APPARATUS FOR PRODUCING A PRODUCT-FILLED CONTAINER

Abstract: The invention provides a method for manufacturing a container filled with a product (11) comprising a substantially tubular body portion (10) of thin-walled plastic or laminated plastic material and a butt-weldable end-piece (13) at each end of the body portion, whereby a first end-piece is fitted to one end of the body portion and the product (11) is introduced into the container via the open end of the body portion, a second end-piece (13) is introduced into the said open body portion end to an intermediate position where it partially projects into the body portion (10), and the plastic material of the body portion end region and the second end-piece is softened through application of heat energy, wherein the end-piece (13), by means of relative displacement between it and the body portion (10), is pressed in to the body portion to its terminal position during evacuation of air from the interior of the container via an opening (20) in the end-piece, and that the said opening (20) is thereafter heat-sealed. The invention also provides an apparatus for carrying out the above method and an end-piece suitable for use in a container thus produced.

Description: TITLE: Method, end-piece and apparatus for producing a product - filled container. TECHNICAL FIELD: The present invention relates to a method, end-piece and apparatus for producing a product-filled container according to the preambles of claims 1, 5 and 7 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 hs 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. It has, however, proven to be difficult to fit the second end-piece without the product in the body-portion open end fouling either the weld-seam or the sealing region. A contributory factor to this problem is, of course, the high production rate which can reach around two units per second. It is possible to avoid this problem by increasing the so-called "head-space" volume between the product and the inner surface of the end-piece. This can, however, lead to negative consequences for the product if there is the risk that it can react with the air in the said head- space. Furthermore, the customer may discriminate against a container with a large head space volume since it does not appear to be completely full. PROBLEM AND SOLUTION: The object of the present invention is thus to provide a method, an end-piece and a device which permits the production of full containers at a high rate and with minimal head-space volume. This object is achieved according to the invention by a method according to claim 1, an end-piece according to claim 5 and a device according to claim 7. Preferred methods, end-pieces and devices according to the invention are given in the respective dependent claims. 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 a device according to the invention, Figure 3 shows the sealing of an evacuation opening in the end-piece, Figure 4 shows the end-piece ' after said sealing, and Figure 5 shows the compression of the weld-seam. 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 cylindrical holder 12 in a (not shown) rotary indexing table which is provided with means for fitting the end- piece in the following sequence of steps. In Figure 1 the 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 and 2. The end-piece 13 comprises an 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 17 for supplying hot gas via directed openings 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"C. After suitable heating, the holder 12 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 Fig. 2. A central nozzle head 18 serves as an abutment for the endpiece 13. The nozzle head 18 is formed with a substantially flat underside which is provided with a central recess 19, intended to receive with generous clearance an evacuation nipple 20 centrally located on the end-piece's transverse wall. The nipple 20 permits the evacuation of air from the head-space between the product 11 and the end wall 15 when the end-piece is pressed into the body portion end. For this purpose the recess 19 is equipped with a branch conduit 21 which exits into a space 22 surrounding the nozzle head 18. In a preferred embodiment of the invention the underside of the nozzle head 18 is also provided with a groove 23 which extends circumferentially above the perimeter of the transverse wall 15. A branch conduit 24 for the supply of cooling gas opens into the groove 23 and accordingly distributes cooling gas around the perimeter of the transverse wall 15. In this way the transverse wall is cooled without affecting the heating of the overlapping wall region of the body portion via -the passages 17. Such a cooling means is described and claimed in our co-pending application "Method and- Apparatus for controlling the temperature of a container end portion during manufacture". A suitable cooling gas can be cold air. Expended cold air flows from the groove 23 via the underside of the nozzle head to the surrounding space 22 from where the utilized cold air and hot gas is drawn from the welding station via passages 25. Since the recess 19 accommodates the evacuation nipple 20 with generous clearance, there is no risk of any quantity of the viscous product being sucked out through the nipple. Figure 5 shows the subsequent step of compressing the U- shaped section 16 whilst still soft so that a seal in this region is achieved. Compression can be carried out -by a vertically displaceable abutment 26 and a plurality of horizontal compression devices 27. These compression devices may be mechanically or elastic-hydraulically operable. Figures 3 and 4 show how the evacuation nipple is sealed by means of a vertically displaceable heated mandrel 28 which is provided with a heating element 29 connected via a cable 30 to an electrical source. The heated mandrel 28 is mounted on an arm 31, vertically displaceable via a piston cylinder 32. As is shown in Figure 4, the evacuation nipple is thus transformed into a closed nipple 33. The invention is not restricted to the above described embodiments, but may be modified within the scope of the appended claims.

Claims: Claims 1. Method for manufacturing a container filled with a product (11) comprising a substantially tubular body portion (10) of thin-walled plastic or laminated plastic material and a butt-weldable end-piece (13) at each end of the body portion, whereby a first end-piece is fitted to one end of the body portion and the product (11) is introduced into the container via the open end of the body portion, a second end-piece (13) is introduced into the said open body portion. end to an intermediate position where it partially projects into the body portion (10), " -arid- the plastic material of the body portion end region and the second end-piece is softened through application of heat energy, characterized in that the end-piece (13) , by means of relative dis¬ placement between it and the body portion (10) , is pressed in to the body portion to its terminal position during evacuation of air from the interior of the container via an opening (20) in the end-piece, and that the said opening (20) is thereafter heat-sealed. 2. Method according to claim 1, characterized in that the heat energy is provided by a hot gas. 3. Method according to claim 1 or 2, characterized in that the weld seams between the tubular body portion (10) and end-piece (13) are subjected to pinching together.. 4. Method according to any of claims 1 to 3, characterized in that during the introduction of the second end-piece (13) into the body portion a quantity of cooling gas is provided to the region of the end-piece (13) adjacent the product (11). 5. End-piece for a container filled with a product (11) , said container comprising a substantially tubular body portion (10) of thin-walled plastic or laminated plastic material and a butt-weldable end-piece (13) at each end of the body portion, characterized by a substantially cylindrical wall region (14) insertable into the tubular body portion (10) which, in its direction of introduction, tapers slightly towards the interior of the body portion and by an end wall (15) which is provided with an outwardly protruding evacuation nipple (20) -. 6. End-piece according to claim 5, characterized in that the insertable portion is provided with an outer, circumferential groove which tapers towards its bottom and is arranged to accommodate the rim of the body portion (10) . 7. Device for butt-welding an end piece (13) to a substantially tubular body portion (10) of thin- walled plastic or laminated plastic material, comprising an application device for placing an end-piece (13) in a defined intermediate position, partially projecting into an end of the tubular body portion, a heating device (17) for supplying warm gas to soften the plastic material of the body portion end region and the end or ends of the outwardly projecting portion of the end-piece (13), and means (12, 18) for displacing the body portion and the end-piece relative to each other until the end-piece is in its terminal position in the body portion, characterized by suction means (25) for evacuating utilized warm air from the weld region and excess air from an evacuation nipple (20) in the end-piece. 8. Device according to claim 7, characterized by means (24) for supplying a cooling gas to an endwall (15) of the end-piece. 9. Device according to claim 8, characterized in that the suction means (25) is adapted to remove utilized cooling gas from the end wall (15) . 10. Device according to claim- 8 or 9, characterized in that the means for supplying cooling gas to the endwall (15) , and the section means (25) form an integral component for introducing the end- piece into the end of the body portion. 11. Device according to claim 8 or 9, characterized in that the means for supplying cooling gas opens into a ring-shaped groove (23) which runs above and substantially around the perimeter of the end wall (15) .

Inventors: LINNER HANS, LINNER, HANS
Applicants: NORDEN PAC DEV AB, NORDEN PAC DEVELOPMENT AB
Application year: 1991
Main classification: B65B31
IPC codes: B29C57, B29C65, B29C67, B65B7, B65B31, B65B51