Device and method for producing sterile containers

Abstract

A method for handling at least sectionally sterile workpieces having a filiable inner volume, wherein the workpieces are each connected to a closure device, and by which the workpieces are guided through a plurality of treatment stations. One of the stations is a sterilization unit, wherein in at least one of the treatment stations, a treatment member is moved through a passage opening of the closure device all the way into the inner volume of the workpiece. The passage opening of the closure device is closed off by a closure element, which opens when the treatment member moves through and closes again upon removal of the member, wherein the closure device sealingly closes the inner volume of the workpiece with respect to an external region.

Claims

1. A method for handling workplaces which are sterile at least ire regions and have a fillable inner volume, the method comprising the steps of: connecting each of the workpieces to a respective closure device; guiding the workplaces and the respective closure devices through a plurality of treatment stations, wherein one of the treatment stations is a sterilization unit; and, in at least one of the treatment stations, moving a treatment member through a passage opening in the closure device into an inner volume of the workplace, wherein the passage opening in the closure device is closed by a closure element that opens when the treatment member moves therethrouqh and closes again when the treatment member is removed, wherein the closure device closes the inner volume of the workpiece in relation to an external region in a sealed manner.

2. The method as claimed in claim 1, wherein. the workpieces are preforms composed of a thermoplastic material for producing blow molded containers which are sterile at least in regions, and/or containers produced in a blow-molding manner from preforms.

3. The method as claimed in claim 2, including guiding the preforms through the plurality of treatment stations of a blow molding machine.

4. The method as claimed in claim 3, including guiding the preforms through a heating unit in which the preforms are conditioned thermally for a blow molding process, and/or through a blow molding station in which the preforms are blow molded to form containers, and/or through inlet, discharge and/or transfer star wheels in which the preforms and/or the containers are transported.

5. The method as claimed in claim 4, wherein each of the preforms is connected to the respective closure device before sterilization takes place in the sterilization unit, in particular wherein, in the sterilization unit, a sterilization member is guided through the passage opening in the closure device in order to introduce a sterilization agent into the inner volume of the preform.

6. The method as claimed in claim 5, wherein the connection takes place upstream of the heating unit, wherein the connection is released at the earliest after departure from the blow molding station.

7. The method as claimed in claim 6, wherein the connection is released only after the blow molded container has been filled with a filling material.

8. The method as claimed in claim 2, wherein the workpiece has a mouth opposite a closed base, a handling ring and an external thread which is arranged on a mouth side of handling ring, wherein the connection of the closure device to the workpiece takes place at the handling ring and/or at the external thread.

9. The method as claimed in claim 8, wherein sealing of the closure device to the workpiece takes place at the handling ring of the workpiece and/or at an end of the external thread that faces away from the mouth.

10. The method as claimed in claim 8, including using a chemical sterilization agent that is guided along the external thread after passing through the inner volume.

11. The method as claimed in claim 10, wherein the chemical sterilization agent is hydrogen peroxide in a flowable state of aggregation.

12. The method as claimed in claim 1, wherein the closure devices are guided in a circuit, wherein the closure devices revolve in a first portion of the circuit in a manner connected to a workpiece and revolve in. a second portion of the circuit without a workpiece, wherein in the second portion of the circuit without a workpiece, sterilization. of the closure devices takes place.

13. The method as claimed in claim 12, wherein sterilization is carried out using a sterilization agent or a sterilizing radiation.

14. The method as claimed in claim 1, wherein the closure devices are carrying devices that carry or hold the workpieces.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) The invention will be explained in more detail below with reference to exemplary embodiments. Exemplary embodiments of the invention are schematically illustrated in the drawings, in which:

(2) FIG. 1 shows a perspective illustration of a blow molding station for producing containers made from preforms,

(3) FIG. 2 shows a longitudinal section through a blow mold in which a preform is stretched and expanded,

(4) FIG. 3 shows a sketch for illustrating a basic design of a device for blow molding containers,

(5) FIG. 4 shows a modified device according to FIG. 3 with an additional filler and closer unit,

(6) FIG. 5 shows a schematic illustration of a first exemplary embodiment of a closure device with a workpiece held by the latter; and

(7) FIG. 6 shows a schematic illustration of a second exemplary embodiment of a closure device.

DETAILED DESCRIPTION OF THE INVENTION

(8) The basic design of a device for forming preforms 1 into containers 2 is illustrated in FIG. 1 and in FIG. 2.

(9) The device for molding the container 2 (blow molding machine) substantially comprises a blow molding station 3 which is provided with a blow mold 4 into which a preform 1 can be inserted. The preform 1 can be an injection-molded part composed of polyethylene terephthalate. In order to enable insertion of the preform 1 into the blow mold 4, and in order to enable removal of the finished container 2, the blow mold 4 is composed of mold halves 5, 6 and of a base part 7, which can be positioned by a lifting device 8. The preform 1 can be held in the region of the blow molding station 3 by a conveying mandrel 9 which, together with the preform 1, passes through a plurality of treatment stations within the device. However, it is also possible to insert the preform 1 directly into the blow mold 4, for example via tongs or other handling means.

(10) In order for a compressed air supply line to be permitted, a connection piston 10, which supplies compressed air to the preform 1 and at the same time undertakes sealing relative to the conveying mandrel 9, is arranged below the conveying mandrel 9. However, it is also conceivable in a modified construction, in principle to use fixed compressed air supply lines.

(11) Stretching of the preform 1 take place with the aid of a treatment member/stretching rod 11 which is positioned by a cylinder 12. In principle, however, it is also conceivable to carry out mechanical positioning of the stretching rod 11 via curved segments which are acted upon by tracking rollers. The use of curved segments is expedient in particular whenever a plurality of blow molding stations 3 are arranged on a rotating blow molding wheel. The use of cylinders 12 is expedient if blow molding stations 3 arranged in a positionally fixed manner are provided.

(12) In the embodiment illustrated in FIG. 1, the stretching system is designed in such a manner that a tandem arrangement of two cylinders 12 is provided. Before the beginning of the actual stretching operation, the stretching rod 11 is initially moved by a primary cylinder 13 into the region of a base 14 of the preform 1. During the actual stretching operation, the primary cylinder 13, with the stretching rod 11 extended, is positioned together with a carriage 15, which carries the primary cylinder 13, by a secondary cylinder 16 or via a cam controller. In particular, it is conceivable to use the secondary cylinder 16 in a cam-controlled manner such that a current stretching position is predetermined by a guide roller 17 which slides along a curved track while the stretching operation is being carried out. The guide roller 17 is pressed against the guide track by the secondary cylinder 16. The carriage 15 slides along two guide elements 18.

(13) After the mold halves 5, 6 arranged in the region of carriers 19, 20 have been closed, the carriers 19, 20 are locked relative to each other with the aid of a locking unit 40.

(14) For adaptation to various shapes of a mouth portion 21 of the preform 1, the use of separate threaded inserts 22 in the region of the blow mold 4 is provided according to FIG. 2.

(15) In addition to the blow molded container 2, FIG. 2 also shows the preform 1 by dashed lines and, schematically, a container bubble 23 being formed.

(16) FIG. 3 shows the basic design of a blow molding machine which is provided with a heating section 24 and a rotating blow molding wheel 25. Starting from a preform infeed 26, the preforms 1 are transported into the region of the heating section 24 by transfer wheels 27, 28, 29. Heating radiators 30 and blowers 31 are arranged along the heating section 24 in order to control the temperature of the preforms 1. After the temperature of the preforms 1 has been adequately controlled, the latter are transferred to the blow molding wheel 25, in the region of which the blow molding stations 3 are arranged. The finished blow molded containers 2 are supplied to a discharge section 32 by further transfer wheels.

(17) In order to be able to form a preform 1 into a container 2 in such a manner that the container 2 has material properties which ensure a long shelf life of foodstuffs, in particular beverages, which are decanted into the container 2, special method steps have to be adhered to when heating and orienting the preforms 1. Furthermore, advantageous effects can be achieved by adhering to special dimensional rules.

(18) Various plastics can be used for the thermoplastic material. For example, PET, PEN or PP can be used.

(19) Expansion of the preform 1 during the orientation operation takes place by supplying compressed air. The supply of the compressed air is divided into a pre-blowing phase, in which gas, for example compressed air, is supplied at a low pressure level, and into a subsequent main blowing phase, in which gas is supplied at a higher pressure level. During the pre-blowing phase, compressed air is typically used at a pressure in the range of 10 bar to 25 bar, and, during the main blowing phase, compressed air is supplied at a pressure in the range of 25 bar to 40 bar. To achieve aseptic blow molding conditions, use is made, for example, of sterile compressed air.

(20) It can likewise be seen in FIG. 3 that, in the embodiment illustrated, the heating section 24 is formed from a plurality of revolving transport elements 33 which are strung together in a chain-like manner and are guided along deflection wheels 34. In particular, it is conceivable for a substantially rectangular basic shape to be defined by the chain-like arrangement. In the case of the embodiment illustrated, a single deflection wheel 34 which is of relatively large dimensions is used in the region of that extent of the heating section 24 which faces the transfer wheel 29 and an infeed wheel 35, and deflection wheels 36 which are of comparatively smaller dimensions are used in the region of adjacent deflections. In principle, however, any other guides are also conceivable.

(21) In order to permit as tight an arrangement of the transfer wheel 29 and of the in feed wheel 35 as possible relative to each other, the arrangement illustrated has proven particularly expedient since three deflection wheels 34, 36 are positioned in the region of the corresponding extent of the heating section 24, specifically in each case the smaller deflection wheels 36 in the region of the transition to the linear courses of the heating section 24, and the larger deflection wheel 34 in the immediate transfer region to the transfer wheel 29 and to the in feed wheel 35. As an alternative to the use of chain-like transport elements 33, it is also possible, for example, to use a rotating heating wheel.

(22) After the blow molding of the containers 2 has been completed, the latter are guided out of the region of the blow molding stations 3 by a retrieval wheel 37 and transported via the transfer wheel 28 and a discharge wheel 38 to the discharge section 32.

(23) In the modified blow molding machine illustrated in FIG. 4, the discharge section 32 is adjoined in an interlocked manner by a filler and closer unit. A transfer wheel 31 removes the blow molded containers 2 from the discharge section 32 and transfers said containers to the rotating filler wheel 42 on which a plurality of revolving filling stations with filling members are arranged. After the filling operation has been completed, the filled, but not yet closed containers 2 pass through the further transfer star wheel 43 to the closer unit 44, which is likewise formed in a rotating manner with closing stations and in which the containers 2 are closed, for example by closure caps being screwed thereon. After passing through the removal star wheel 45, the filled and closed containers 2 leave the filler and closer unit via the discharge unit 46.

(24) FIG. 5 shows, in a schematic illustration, a first exemplary embodiment of a closure device according to the invention, which is designed as a carrying element 59 for a workpiece without restricting the basic inventive concept. The carrying element 59 according to the invention is shown with a workpiece, which it holds, in the form of a preform 1, of which only the mouth region 21 with a neck ring 51 and an external thread 52 is illustrated. The preform 1 is illustrated arranged in a blow molding station 3 with the blow mold halves 5, 6.

(25) The carrying element 59 projects with a holding portion 53 through the mouth 21 into the interior of the preform. The preform 1 is clamped on an elastic sealing ring 54, which is arranged on the outer side of the holding portion 53, and is held as a result by the carrying element 59, which is designed in the manner of a clamping mandrel. The carrying element 59 has as a passage opening 61, over the entire axial extent thereof, a central bore which extends on the preform side from the holding portion 53 through the main body 55 as far as the end thereof facing away from the preform. Said end of the passage opening 61 that faces away from the preform is closed in a basic state against the entry of germs by a duckbill valve 56.

(26) In the illustrated state of FIG. 5, a blow molding nozzle 10 bears against a contact portion 57 of the main body 55. A sealing ring 58 which is arranged on the contact portion 57 ensures pressure-tight sealing between the main body 55 and the blow molding nozzle 10. A stretching rod 11 passes through the blow molding nozzle 10 and, during insertion into the passage opening 61, has moved the duckbill valve 56 into the open state shown. After removal of the stretching rod, the duckbill valve 56 automatically returns into the closed state. The stretching rod 11 serves in a known manner for stretching the preform 1 during the desired biaxial orientation of the preform material during the blow molding process. The stretching rod 11 passes through the entire length of the passage opening 61. The stretching rod 11 is sealed here by means of an annular lip seal 60 which extends in a cross-sectionally constricting manner radially inward from the main body 55 into the passage opening 61 such that compressed air which is supplied, for example sterile compressed air supplied through the stretching rod, cannot escape.

(27) For the purpose of handling by handling means of the blow molding machine, the main body 55 has, on the cylindrical side surfaces thereof, handling elements in the form, in the exemplary embodiment shown, of two ribs 62 which are spaced apart and therefore equidistant in a horizontal plane and at which engagement can take place in a handling manner, for example by tong-like handling means known in the prior art. In addition, a magnetic ring 63 is arranged between said ribs 62, and therefore a magnetic handling engagement is also possible.

(28) FIG. 6 shows, in a schematic illustration, a second exemplary embodiment of a closure device according to the invention and likewise designed as a carrying element 69. Unlike in FIG. 5, the carrying element does not engage in the preform 1, but rather engages on the outside of the preform 1. Radially resilient latching lugs 65 engage behind the encircling securing ring 66 arranged at the bottom end of the thread 52 while a sealing element 67 of the carrying element 69 is pressed against the neck ring 51 of the preform 1. The central passage opening 61 of the supporting element 69 is controlled by a ball valve 70 which is shown in an open state suitable for the passage of a treatment member or for the introduction of a medium. When the ball valve 70 is closed and because of the sealing contact of the carrying element 69 with the preform 1, the interior of the preform is closed off from an external region; an entry of germs is reliably prevented.

(29) The carrying element 69 also has, on the side thereof facing away from the preform, a contact region 57 to which a sterilization member 71 is connected in a sealed manner. Sealing also takes place here between the carrying element 69 and sterilization member 57 by means of an annular seal 72 arranged in between. Said annular seal 72 can optionally be arranged on the sterilization member 71 or, as illustrated, on the carrying element 69.

(30) A sterilizing chemical fluid is fed by the sterilization member 71 into the passage opening 61 and exits into the preform 1 in the direction of the depicted arrows. In the example shown, the flow conduction is selected in such a manner that the sterilizing fluid, after exiting from a mandrel-like region of the carrying element 69 projecting into the preform 1, initially flows in the base direction of the preform 1 in order to reliably and as completely as possible brush over and sterilize the inner wall of the preform 1. The reverse flow of the sterilizing fluid takes place along the outside of the mandrel-like region; as a result, the fluid also brushes over those regions of the carrying element 69 which are critical in terms of germs and face the preform 1, and also leads here to a desired freedom from germs. The fluid flows out of the preform 1 and is conducted along the external thread 52 in the arrow direction by means of a channel formed between the preform 1 and the carrying element 69 before said fluid can escape or is returned through outlet openings 73 of the carrying element 69. The outlet opening 73 is secured (in a manner not illustrated) against the penetration of germs, for example by means of a nonreturn valve.

(31) With reference to FIGS. 3 and 4, the carrying element according to the invention can also be connected, for example, upstream of the heating section 24 in the region of the inlet star wheel 27 to the entering preforms 1. The further handling could then take place by engagement in the carrying element. After carrying element and preform 1 are connected, the interior enclosed by said two connected elements is protected against the penetration of germs.

(32) The connection of preform and carrying element is intended to take place upstream of the sterilization unit 80 which, in the exemplary embodiment illustrated in FIG. 3, is illustrated arranged in the discharge-side region of the heating section 24. After passage through the sterilization unit 80, the closed interior of the preform 1 is free from germs and is kept free from germs over the further transport path thereof by the carrying element. In a possible refinement of the invention, the connected unit consisting of preform 1 and carrying element passes through the heating section 24, the sterilization unit 80, the blow molding wheel 25 (wherein there is a unit composed of container and carrying element downstream of the blow molding wheel) and the transport units arranged in between, for example, the transfer star wheels illustrated. Separation of the unit can take place, for example, on the output side of the blow molding machine, and the free carrying elements can then be supplied for a renewed use thereof in a return transport path 81. A further sterilization unit 82 which subjects the carrying elements to complete sterilization can be arranged on said return transport path 81.

(33) In particular in the case of an interlocked arrangement of a blow molding machine with a filler and/or closer, the invention also permits a variant embodiment in which the unit composed of container and carrying element is transferred by the blow molding machine to the filler and/or to the closer and passes as a unit through the filler and/or the closer.

(34) Alternative closure devices according to the invention can be formed without a holding or carrying function. In this case, the workpieces are carried, for example, by tongs or other suitable holding devices, while the closure device, as described, accessibly closes an interior of the workpieces and is connected only to the workpiece, but does not have a substantial carrying or holding function, if any at all, for the workpiece, but rather is limited to the closure and lock function.