GB2271347A

GB2271347A - An apparatus for filling sterile contents into interiorly sterile, wholly sealed containers

Info

Publication number: GB2271347A
Application number: GB9218733A
Authority: GB
Inventors: Hans Rausing
Original assignee: Tetra Laval Holdings and Finance SA; Tetra Alfa Holdings SA
Current assignee: Tetra Laval Holdings and Finance SA
Priority date: 1992-09-04
Filing date: 1992-09-04
Publication date: 1994-04-13
Anticipated expiration: 2012-09-04
Also published as: GB2271347B; GB9218733D0

Abstract

An apparatus for filling sterile contents into interiorly sterile, wholly sealed containers 5, preferably such as are produced by pressure blowing comprises a filling chamber with a sterile atmosphere 7 and an infeed portion 2 in which the container exteriors are washed with a sterilization liquid, for example hot hydrogen peroxide. Containers 5 conveyed to the sterile chamber 7 on conveyor means in the infeed portion 2 are surrounded by bristles or sponge material 4 and are externally washed and sterilized thereby. The bristles or sponge material may be mounted on the conveyor means or stationary in the infeed portion. In the sterile chamber 7 portions 10 of the containers 5 are severed eg by an electrically heated cutting wire or blade 8 to form an opening through which the containers 5 are filled by filler heads 14 and thereafter sealed with a cover foil 21 which is sterilized, eg by passing between bristles or sponge material, and then heat sealed over the openings. The containers are optionally fitted with a snap or screw cap 25, before being discharged from the sterile chamber 7. <IMAGE>

Description

AN APPARATUS FOR FILLING STERILE CONTENTS INTO INTERIORLY STERILE, WHOLLY SEALED CONTAINERS TECHNICAL FIELD The present invention relates to an apparatus for filling sterile contents into interiorly sterile, wholly sealed, preferably blown containers of plastic material.

BACKGROUND ART Within the food engineering art, it is known that the shelf life of most foods can be greatly prolonged if the food is sterilized or if its bacteria content is reduced, and is subsequentiy packed in interiorly sterile, bacteria-tight packages under aseptic conditions.

One method of producing a package with sterile contents is first to fill the package and seal it in a bacteria-tight manner, and thereafter heat-treat both package and contents in an autoclave. Such a process entails that the product must be heated for a long time, which implies, for instance for milk and other dairy produce, a manifest change in the flavour and colour (caramelization) of the produce. Considerably improved results will be obtained using so-called UHT (Ultra High Temperature) treatment of milk and dairy produce. In such treatment, the product is flash heated to a temperature of approx. 140"C for roughly 4 seconds, during which time practically all bacteria and microorganisms will be exterminated.Milk which has been UHT treated and then packed in interiorly sterile packages under aseptic conditions can be stored in its package for several months without becoming sour. Moreover, the changes in flavour which affect the milk as a result of UHT treatment are substantially less discernible than those which occur in lengthy heat treatment such as autoclaving.

Hence, the technique for treating and packing foods such as milk in order to achieve a long shelf life is already in place, but it has proved that difficulties arise in the packing of a sterile product, for instance milk, juice other other foods, in prefabricated, interiorly sterile containers, for example wholly sealed, pressure blown plastic bottles.

A plastic bottle or plastic container may be produced by blowing of an extruded hose or a preformed blank of plastic material employing modern plastic pressure blowing machines of which there are numerous designs available on the market. One common principle is that a plastic hose or plastic tube is extruded from an extruder nozzle down into a mould consisting of two mould halves. When a sufficiently long tube has been fed down into or between the mould halves, the tube is severed from the extruder nozzle and a blowing nozzle is inserted in the mouth of the tube whose lower region has been sealed, for example by the mould halves being caused to close and in such instance seal the lower edge zone of the tube.With the aid of compressed air or compressed gas fed into the tube portion1 the hot and plasticized tube portion is expanded and blown into abutment against the inner contour of the mould halves. That part of the blown tube which is located above the mould halves or parts can be sealed after removal of the blowing nozzle, there being then obtained a wholly sealed and closed container package which can be removed from the mould halves once these have been separated. Because the inner region of the tube is at an elevated temperature during the blowing operation, the inside of the container will be sterile and if there is any risk that the blowing air might infect the inside of the container, sterile-filtered air can be employed.

Thus, the basic precondition is that of obtaining, by a blowing operation, a completely sealed and closed, interiorly sterile container which is intended to be filled with sterile contents. Such a container can also be produced by so-called injection moulding of container parts from a plastic material, or, for example, by joining together two vacuum-drawn hollow bodies to one another along their edge zones so that a closed hollow body is obtained. Closed or sealed, interiorly sterile containers of the type contemplated here must be filled in a sterile chamber in order that filling take place under aseptic conditions, and an opening or mouth to the container must similarly be created within this sterile chamber.Even if the interior of the container package is sterile, its outer surfaces are exposed to an unsterile environment, which entails that bacteria and other microorganisms will be present on the outer sides of the container. This means that the containers must be exteriorly cleaned and sterilized before they can be fed into the sterile chamber for filling. Such treatment may, for example, be carried out by dipping the containers in a sterile bath, but there is, however, a risk of re-infection before the containers are fed into the sterile chamber.

SUMMARY OF THE INVENTION According to the present invention, whose characterizing features are apparent from the appended Claims, external sterilization and infeed into the sterile chamber are combined, in that the sealed containers are applied between two conveyor belts fitted with bristles, by means of which conveyor belts the containers are transported into the sterile chamber. During the time of transport, the containers are surrounded by the above-mentioned bristles which are drenched with a sterilization liquid, for example hydrogen peroxide. In order to enhance the sterilization effect, the hydrogen peroxide can be heated. In the sterile chamber, portions such as the upper portion of a bottleneck-like part of the containers are severed, the container then being filled with sterile contents and sealed with a previously sterilized plastic film.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING One embodiment of the present invention will now be described in greater detail hereinbelow, with particular reference to the accompanying schematic Drawing which shows a cross section through an apparatus according to the invention.

DESCRIPTION OF PREFERRED EMBODIMENT The apparatus according to the present invention consists of an infeed portion 2 in the form of a tunnel or chamber which has an entry aperture 1 through which are introduced wholly sealed, interiorly sterile containers 5 of plastic. In the infeed portion 2, there are disposed two parallel endless conveyor belts 3 which each display bristles or a sponge coating 4 disposed on the belts 3. The conveyor belts 3 are driven by means of and passed over drive wheels 6, and the conveyor belts 3 are disposed such that the bristles from the belts are in contact with one another or overlap one another along those parts or runs of the conveyor belts 3 which are turned to face one another. The containers 5 are disposed to be accommodated between the conveyor belts 3 and, during transport therebetween, to be wholly surrounded by bristles 4 or sponge material.

Spray nozzles 29 are disposed in the infeed portion 2, with the aid of which nozzles a sterilization liquid (in this case hydrogen peroxide) is sprayed over the bristles 4 of the conveyor belts 3 in order to completely drench the bristles with sterilization liquid. The conveyor belts 3 are preferably designed so that they are provided with holes or apertures through which the sterilization liquid can run so that excess sterilization liquid is collected in a sump 27 disposed at the bottom of the infeed portion 2. The sterilization liquid can be recycled by being pumped from the sump 27 by a pump (not shown) via the conduit 28 in order to be resprayed out against the conveyor belts 3. The infeed portion 2 is interconnected with a sterile chamber 7 in which excess pressure of sterile-filtered air is maintained.In the sterile chamber 7, there is disposed a conveyor belt 11 which is driven with the aid of drive rollers 12. The conveyor belt 11 is arranged to carry the abovementioned containers 5 and transport them through the sterile chamber, and the connecting portion of the sterile chamber 7 to the infeed portion 2 displays a severing device 8 which may consist of a hot wire or a knife with a hot edge, by means of which the top of the containers 5 is cut off for forming an opening or mouth. The severed portions 10 of the containers 5 are removed through a channel 9, for example by means of suction which takes place in the direction of the arrow.

The opened containers 5 are transported by means of the conveyor belt 11 into the sterile chamber 7 where they are filled with previously bacteria-reduced contents with the aid of the filler unit 13 which displays a number of filler pipes 14. The filled, but as yet still open, packages are transported further in the sterile chamber 7 to a sealing unit 20 which consists of a heated device which is movable in the vertical direction.

Sealing of the containers 5 proceeds in such a manner that a cover foil 21 is placed over the mouth or opening of the container 5, whereafter the sealing unit is brought with its hot working surface into contact with the cover foil which is heat-sealed against the edge zone of the mouth of the container for the formation of a cover portion covering the mouth or opening and tightly sealing against the opening edge. The cover foil material is unreeled from a magazine reel 15 which is preferably located outside the sterile chamber 7, the foil material being inserted through a slot in the chamber. In order to sterilize the cover foil material, this is caused to pass between two endless belts 17 which are driven over drive rollers 19, the belts 17 being fitted with bristles or sponge coating 18.In the same manner as previously described, the bristles 18 are drenched with a sterilization liquid which may preferably consist of hydrogen peroxide. By means of the bristles, the sterilization liquid is brought into contact with the cover foil web 16 which1 in such instance, is surface sterilized on both sides before being fed into the sterile chamber 7. The cover foil web or film 16 is passed over a bending roller and a guide arrangement (not shown) over the opening or mouth of the containers 5 and, on the downward stroke of the sealing unit 20, the forward portion 21 of the cover foil is severed by means of a schematically illustrated knife 22. When the cover film or cover oblate 21 has been applied over the mouth of the container 5, the sealing unit 20 is raised so as to make room for a new container 5, new cover film 16 being advanced at the same time.

The container fitted with cover film is now bacteria-tight sealed and can technically be discharged from the sterile chamber for shipping to retail outlets. However, in certain cases, it is desirable that the package be provided, in addition to the cover foil, with a reclosable sealing portion or cap portion, and the apparatus according to the present invention may, to this end, be provided with a cap applicator 24 by means of which bottle caps 25 which are taken from a cap magazine 23 are applied over the cover foil 21.These caps 25 may either be designed with so-called snap catch, i.e. the container is fitted beforehand with a projecting snap edge over which the cap 25 can be forced, or alternatively the container 5 is fitted with a thread, in which event the cap 25 is correspondingly threaded and can be screwed or;tto the container 5 over the cover foil 21 in order to make possible reclosure of the container 5 once it has been opened.

Finally, the filled and sealed container 5 is discharged from the sterile chamber 7 through the opening 26.

In the embodiment described herein, it is assumed that the conveyor belts 3 and 17 are fitted with a bristle or sponge material coating secured to the belts, but it is also conceivable without departing from the inventive -concept as herein disclosed that the conveyor belts 3 and 17 consist of smooth belts or belts provided with anchorages for the containers 5, and that the bristles 4 are instead mounted on immobile devices and directed in between the belts 3 and 17, respectively, so that the containers 5 and film web 16, respectively are drawn by means of the belts 3 through the immobile bristles which, in the manner described previously, carry a sterilization liquid.It has further been disclosed in the described exemplifying embodiment that the severing device 8 should consist of a hot wire or hot knife edge, but it is naturally conceivable that the knife instead consist of a rotary or reciprocating knife edge - the principle matter at hand is that the upper portion of the completely sealed and closed container 5 is efficiently severed so that a mouth or opening is exposed. In the dimensioning of the containers 5, they have of course been designed such that the severed portion 10 is clearly defined and that the mouth being formed will have a smooth and uniform surface for applying the cover foil 21.As has been mentioned earlier, the containers 5 may advantageously be provided, during the manufacturing process, with threads or snap edges and, in order to make possible application of snap caps or screw caps 25, the severed surface created by the severing device 8 must be clearly defined. In order to save material, the severed portion 10 should be as thinwalled as possible and in addition to saving plastic material by making the severed portion thin-walled, a deformation zone will also be created, which is often necessary. The reason why a deformation zone is needed is that the blown container 5 is filled with hot blowing air after being produced.

When the container 5 has cooled, the blowing air contracts in volume and partial vacuum occurs within the container 5. This partial vacuum will tend to deform the outer contours of the container 5, which may cause difficulties on infeed of the containers 5, since the individual containers will not have the same outer contours after deformation. If, during the blowing process, the portion 10 intended for severing is designed so as to be substantially thinner than the walls of the container 5, the deformation caused by the partial vacuum in the container 5 will be localized at the above-mentioned thinner portion 10 intended for severing, while the remainder of the container 5 is not deformed.

In the illustrated embodiment, the filler unit 13 is provided with a number of filler pipes 14, indicating that filling may take place stepwise or portionwise, i.e. that only a part of the contents is filled by means each one of the filler pipes 14, final filling not taking place until the last filler pipe 14 in the row or battery of filler pipes. It is further assumed in the illustrated embodiment that advancement through the apparatus takes place stepwise, but a continuous process is also conceivable, on condition that the filler unit 13, like the cover foil applicator 20 and the cap applicator 24 accompany the movement of the belt 11 during the working operation.

It has proved that the apparatus according to the present invention is simple and economical in design and construction and gives good results with but slight risk of infection of the sterile chamber 7.

The present invention should not be considered as restricted to that described above and shown on the Drawing, many modifications being conceivable without departing from the spirit and scope of the appended Claims.

Claims

CLAIMS:

1. An apparatus for filling sterile or bacteria-reduced contents into interiorly sterile, wholly sealed, plastic containers, said apparatus comprising: an infeed portion (2); a sterile filling chamber (7); first conveyor means (3) for conveying said containers (5) through said infeed portion (2) to said sterile chamber (7); washing means (4, 29) within said infeed portion (2) for drenching the conveyed containers (5) with a sterilization liquid; cutting means (8) for forming filling openings in the washed containers (5); filling means (13) disposed in said chamber (7) to fill the opened containers (5) with said contents; and container sealing means (17-22) for sealing closed the openings in the filled containers (5).

2. An apparatus as claimed in Claim 1, wherein the container sealing means comprises sterilizing means (17,18) for sterilizing a web (16) of plastic film and closure means (20,22) for separating portions of the sterile web (16) and sealing the separated portions (21) over the respective openings in the filled containers (5).

3. An apparatus as claimed in Claim 1 or Claim 2, wherein the washing means comprises flexible wiping means (4) drenched with the sterilization liquid.

4. An apparatus as claimed in Claim 3, wherein said wiping means (4) is mounted on said first conveyor means (3) for movement therewith.

5. An apparatus as claimed in Claim 3, wherein said wiping means (4) is stationarily mounted in said infeed portion (2).

6. An apparatus as claimed in any one of Claims 3 to 5, wherein said flexible wiping means comprises bristles (4).

7. An apparatus as claimed in any one of Claims 3 to 5, wherein said flexible wiping means comprises sponge material.

8. An apparatus for filling sterile or bacteria-reduced contents into interiorly sterile, wholly sealed, preferably blown containers of plastic material, characterized by a) an infeed portion (2) including a first conveyor means comprising at least one conveyor belt (3) having bristles (4) projecting from the surface of the conveyor belt (3); b) means (29) for drenching said bristles (4) with a sterilization liquid; c) means (8) for severing and removing portions (10) of said sealed container (5) to create filling openings in said containers (5); d) a sterile chamber (7) in which a sterile atmosphere is maintained and in which the opened containers (5) are disposed to be filled with sterile contents by means of a filler unit (13) disposed in said sterile chamber (7); and (e) a container sealing means having means (17, 18) for sterilizing a web (16) of plastic film, means (18) for inserting said web (16) into said sterile chamber (7), and means (20,22) for separating portions (21) of said web (16) and sealing said portions (21) over the openings in containers (5).

9. An apparatus as claimed in Claim 6 or Claim 8, wherein the bristles are mounted on parallel, endless belts (3) of the first conveyor means and arranged such that the bristles (4) are, from mutually facing proximal parts or runs of the belts (3), directed towards each other in such a manner that the containers (5) transported between the belts (3) are be surrounded by said bristles.

10. An apparatus as claimed in any one of the preceding claims, wherein the first conveyor means (3) has holes through which the sterilization liquid may pass.

11. An apparatus as claimed in any one of the preceding claims, wherein the infeed portion (2) comprises a tunnel (2) having a bottom compartment (27) for collecting sterilization liquid.

12. An apparatus as claimed in any one of the preceding claims, wherein the infeed portion has spray devices (29) for supplying the sterilization liquid.

13. An apparatus as claimed in any one of the preceding claims, wherein the cutting means comprises an electrically heated cutting wire or edge (8).

14. An apparatus as claimed in any one of the preceding claims, wherein the container sealing means comprises a magazine reel (15) of a thermoplastic web or film (16) located outside the sterile chamber (7), second conveyor means comprising two endless belts (17) for feeding said web or film (16) into the chamber (7), bristles (18) mounted on said belts (17), means for drenching said bristles (18) with sterilization liquid, and means (22) for separating parts (21) of said web or film (16) and applying said separated parts over the openings in the containers (5) to provide a tight seal over said openings.

15. An apparatus as claimed in any one of the preceding claims, comprising means (24) for providing the filled and sealed containers with a second closure member (25) which is disposed in such a manner that it is removable and reclosable.

16. A method of filling and sealing interiorly sterile, wholly sealed plastic containers with sterile or bacteria-reduced contents, comprising feeding said containers (5) to a sterile chamber (7) by first conveyor means (3) disposed in a tunnel (2) having washing means for drenching at least part of said containers with a sterilization liquid; forming an opening in said part of the washed containers by cutting means (8) disposed in the sterile chamber (7); filling the containers (5) with sterile or bacteria reduced contents; and sealing the openings in the filled containers.

17. A method as claimed in Claim 16, wherein the containers are filled and sealed using apparatus as defined in any one of Claims 2 to 15.

18. A method of filling and sealing interiorly sterile, preferably blown and wholly sealed plastic containers with sterile or bacteria-reduced contents, characterized in that a) said containers (5) are inserted in a sterile chamber (7) by means of belts (3) disposed in a tunnel (2) and fitted with bristles (4) which are drenched with a liquid sterilization agent and wholly surrounded the containers (5) to sterilize the outsides of the containers (5), b) the exteriorly and interiorly sterile, sealed containers (5) fed to the sterile chamber (7) are opened by means of a device (8) disposed in the sterile chamber (7), portions (10) of the containers (5) being separated and removed for the purpose of establishing a container opening, c) the opened containers (5) are filled with sterile or bacteria-reduced contents, and d) cover strips (21) of sterilized plastic film (16) are caused to cover and be sealed over the container openings.