Method for sterilizing containers

Abstract

The invention relates to a method for sterilizing containers (1) with a circulating transport device having a plurality of container receptacles (3), wherein the containers (1) are received at a receiving area (4) by an associated container receptacle (3), transported with the container receptacle (3) along a transport path (5), and discharged at a discharge area (6) by the associated container receptacle (3). According to the invention, the unloaded container receptacles (3) are exposed to a sterilizing agent on a return path (7) between the discharge area (6) and the feed area (4), wherein the sterilizing agent is at least partially transferred to the containers (1) received in the receiving area (4). The invention also relates to a sterilization system for carrying out the method.

Description

The invention relates to a method for sterilizing containers with a revolving transport device having a plurality of container receptacles, wherein containers are received in a receiving region of in each case one associated container receptacle, are transported with the container receptacle along a transport path and are discharged from the associated container receptacle at a discharge region. The invention further relates to a sterilization system for carrying out the method.During movement along the transport path, the containers can be sterilized.The invention relates in particular to the field of the beverage industry, wherein the containers are then designed as bottles, in particular disposable PET bottles or as preforms for forming such bottles. During sterilization of the bottle or preform, the latter is moved with the revolving transport device, wherein this is, for example, a revolving chain or preferably a starwheel with the container receptacles arranged thereon.The container receptacles are usually formed by grippers or fixed pockets, wherein the containers are then received by the container receptacle on at least one contact surface.In the known methods for sterilization, the sterilizing agent for the treatment of the preform or bottle is applied to the surface or directed onto the surface. Bottles or preforms made of PET (polyethylene terephthalate) frequently have a so-called neck ring on a bottle neck on which these containers can be handled. When the container is then held on or in the region of the neck ring, for example with a gripper, the corresponding region of the surface is covered. There is then the risk that there is no adequate sterilization, i.e. there germs, spores, viruses or microorganisms generally remain or are not killed.Against this background, methods and devices are known from practice in which the sterilization takes place in two stages and the containers are then transported with two transport devices and stored differently or gripped differently during the transfer. This ensures that the entire container surface becomes accessible, but this results in increased outlay.A method of the generic type is known from EP 2 742 958 B1, wherein the container receptacles are designed as gripping systems. The gripping systems each comprise two pairs of gripping clamps at different heights, wherein during the transport of the containers along the transport path gripping takes place and thereby all areas of the surface are also accessible. However, a considerable outlay on apparatus results, wherein the shape of the containers and the gripping force of the gripping clamp must be matched to one another such that gripping can take place at different levels without slipping off. In addition, depending on the type of sterilant, certain shutdown effects may also occur with the clamps immediately overlying one another.The object of the invention is to specify a method for sterilizing containers and a sterilization system for this purpose, which allow reliable sterilization with the least possible outlay.The invention and the object are achieved by a method for sterilizing containers according to claim 1 and a sterilization system for carrying out the method according to claim 9.Proceeding from a method of the generic type for sterilizing containers, it is accordingly provided according to the invention that the unloaded container receptacles are acted upon with a sterilizing agent on a return path between the dispensing region and the loading region, wherein the sterilizing agent is at least partially transferred to the containers which are received in the receiving region.According to the invention, in the usual production operation, which can also be referred to as transport operation with respect to the containers, sterilizing agent is applied continuously to the container receptacles, namely at least where the containers are subsequently received by the container receptacles and carried during transport. The sterilizing agent initially applied to the container receptacles is then transferred to the containers by the direct contact. The direct contact with the containers takes place exactly where the containers are accommodated and carried by the container receptacle, wherein these regions are otherwise at least partially concealed in the case of conventional sterilization. The sterilizing agent can then also effectively act on the regions which are covered by the container receptacle.In the context of the invention, it is usually not important to sterilize the container receptacle itself, but to transfer the sterilizing agent to the containers as described. It is understood that the sterilizing agent is then transferred to the containers in a still active and effective state.In the case of conventional sterilizing agents, this specification can also be achieved because, as a rule, only a comparatively short path is provided between the exposure of the container receptacle to the sterilizing agent and the subsequent reception of the containers by the container receptacles.This applies in principle to different configurations of the transport device, which can be realized, for example, as a chain or with a starwheel. In an embodiment with a starwheel, a rotation angle of less than 90°, preferably less than 45°, can be provided in particular between the application of the sterilizing agent and the receptacle.In an embodiment with a starwheel, the transport path between the receiving region and the dispensing region also extends for effective process control and space utilization preferably over an angle of 180° to 330°, particularly preferably 240° to 300°. With respect to a full circle, the return path then remains, on which the container receptacles are unloaded and can be provided with the sterilizing agent.From the container receptacle, the sterilizing agent is usually transferred only to a small part of the surface of the containers, namely where a direct contact takes place. The transfer of the sterilizing agent to the containers in this way is usually provided within the scope of the invention as a supplement to a sterilization of the remaining surface.Thus, according to a preferred embodiment of the invention, it is provided that a main sterilization agent is applied to the containers along the transport path on a container inner side and / or a container outer side. The designation as main sterilization means is merely intended to illustrate that sterilization of the usually significantly larger exposed surface on the inside of the container and / or the outside of the container is thus provided. In this connection, it is clear that the same substance can be provided as sterilization agent and main sterilization agent in this sense.Hydrogen peroxide (H 2 O 2) is particularly suitable as a sterilizing agent or main sterilizing agent. In principle, however, other substances such as alcohol, alkali solution, peracetic acid or similar liquids which have a sterilizing effect are also possible.With regard to the sterilizing agent applied to the container receptacles, it is necessary that this may then be transferred to the containers as a fluid and in particular liquid.With regard to sterilization of the remaining surface on the inside and / or outside of the container, however, irradiation by means of UV light is also possible for sterilization, in addition to the use of the main sterilization agent.It should be noted that irradiated UV light is directly effective at the surface, wherein PET is opaque as a preferred material for the containers, in particular in the form of bottles or preforms in the corresponding wavelength range. Similar to the application of the main sterilization agent to the inside of the container and / or the outside of the container, shut-off effects can then result at the container receptacle in the case of UV light, so that sterilization by means of UV cannot take place in the concealed regions. According to the invention, the sterilizing agent previously applied to the container receptacles is then effective there.As also already explained above, the containers are preferably bottles or preforms made of plastic, in particular PET, which have a neck ring. Such containers can then be held on the neck ring in a particularly simple manner.In the case of containers in the form of preforms, the described sterilization can be carried out, in particular before their conversion into bottles, by compressed air or by the filling of the filling material (Fromfill method). Bottles can be sterilized, for example, before a filling process. With particularly high hygiene requirements, multiple sterilization is also possible at different points of an entire method. For example, it is conceivable to sterilise a preform first and subsequently a bottle formed therewith in a plurality of steps.For example, container receptacles in the form of simple grippers can grip the container directly above or below the neck ring. An arrangement of the gripper under the neck ring can be particularly advantageous within the scope of the invention. The neck ring can then rest from above on the gripper, which usually has two gripping jaws, whereby a reliable transfer of the sterilizing agent can be achieved.Especially because the regions of the containers covered by the container receptacle are provided with sterilizing agent by a direct transfer within the scope of the invention, these contact regions can optionally also be made somewhat larger because adequate sterilization can also be ensured there. According to the embodiments according to the prior art, the person skilled in the art is in an effort to minimize as far as possible the covered regions which are not to be sterilized.The sterilizing agent, in particular in the form of H 2 O 2, can be provided as a gas or mist on the return path and then condense on the container receptacles guided past or precipitate thereon. The sterilizing agent can be vaporized and discharged with air and / or water vapor from a discharge device in the form of a nozzle or the like, for example, in order to then deposit on the container receptacle as described. As a result of the condensation or precipitation of mist, the sterilizing agent is then applied as a liquid to the container receptacle.For example, it can be provided that a vapor mixture of water vapor, hydrogen peroxide vapor and air is discharged, preferably continuously, wherein in particular a vapor temperature between 110° C. and 150° C., in particular approximately 120° C., is suitable.In order that the sterilizing agent can precipitate or condense on the container receptacles in a particularly reliable manner, active cooling of the container receptacles before exposure to the sterilizing agent is also possible in principle. For example, a cooling device can be provided, which in particular conducts a cold fluid, for example cold air, liquid nitrogen or the like, onto the container receptacles before the exposure to the sterilizing agent takes place.In principle, however, other types of wetting are also possible. Besides direct spraying, application or painting with a sponge, a brush or the like is also possible. For example, corresponding discharge devices can be arranged on the return path in such a way that the container receptacles are guided past it in direct contact.The amount of sterilizing agent which is applied on the one hand to the container receptacles and on the other hand subsequently transferred to the containers depends in particular on the contact surface between containers and container receptacle and on the type of sterilizing agent. In particular with regard to H 2 O 2 but also other sterilizing agents, it is provided according to a preferred embodiment of the invention that the sterilizing agent is applied to a contact surface of the container receptacle at the return path with an area-specific quantity of 0.2 μl / cm 2( microliters per square centimeter) to 3 μl / cm 2. An area-specific amount of 0.3 μl / cm 2 to 2 μl / cm 2 and in particular 0.4 μl / cm 2 to 1 μl / cm 2. is preferred.The stated surface-specific deficiencies relate to each circulation, wherein-as has already been explained above-sterilizing agent is usually also transferred to the container receptacles during each circulation and is transferred from there to the containers.The invention also relates to a sterilization system for carrying out the method described above. The sterilization system has a revolving transport device having a plurality of container receptacles, which has a receiving region and a removal region and is configured to receive containers at the receiving region with a respective associated container receptacle, to transport them with the container receptacle along a transport path and to discharge them at the dispensing region. Between the dispensing region and the receiving region, a return path for the container receptacles is provided. A sterilization device for the containers is arranged on the transport path, wherein a first discharge device is provided on the return path in order to apply a sterilizing agent to the container receptacles.The first discharge device is provided in order to be able to sterilize areas which are then covered by the sterilization device already before sterilization. The sterilization device can have at least one second discharge device and / or a UV light source.As has also already been explained above, the container receptacles can be designed as grippers, wherein the grippers can then each have flat contact surfaces for the planar support of a neck ring.Regardless of the specific configuration of the container receptacles, it is advantageous if the container either bears directly and a transfer of the sterilizing agent is possible there or if the remaining regions are substantially exposed. Against this background, it is particularly expedient if the preferably planar contact surfaces end at edges or steps in such a way that a larger free space is provided directly there and then the inside and / or outside of the container is easily accessible there for separate sterilization.The invention is explained below with reference to a drawing.The single FIGURE shows a sterilization system for sterilizing containers.The single FIGURE shows a schematic view of a sterilization plant to which containers 1 in the form of preforms are supplied by way of example. The sterilization system has a starwheel 2 which carries a plurality of container receptacles 3 in the form of grippers.As can be seen from the figure, the containers 1 are accommodated in a continuous operation at an accommodation region 4 by an associated container receptacle 3 in each case, transported with the container receptacle 3 along a transport path 5 and discharged at a discharge region 6 from the associated container receptacle 3.The transport path 5 extends over approximately 3 / 4 of the circumference of the star wheel 2, wherein a return path 7 remains between the dispensing region 6 and the receiving region 5 opposite the transport path 5, on which return path the container receptacles 3 are unloaded.On the return path 7 a first discharge device 8 is arranged, with which a sterilizing agent is applied to the container receptacles 3. As a sterilizing agent, for example, H 2 O 2 can be evaporated and conveyed in gaseous form with air and / or water vapor in order then to condense on the surface of the container receptacles 3 and form a liquid film there.When the containers 1 are then subsequently received by the container receptacles 3 provided with the sterilizing agent during the rotation of the star wheel 3, the sterilizing agent is transferred in regions to the containers 1 by direct contact, namely where the containers 1 are held by the container receptacle 3.In the exemplary embodiment shown, the containers 1 each have a neck ring 9, on which the containers 1 are supported. The sterilizing agent is thus transferred in particular to the neck ring 9.Along the transport path 5, a sterilization device with a second discharge device 10 is furthermore provided, with which a main sterilization agent is applied to a container inner side and a container outer side. The distinction between the terms sterilizing agent and main sterilizing agent refers in particular to the fact that different regions of the container 1 are sterilized, wherein the same substance as H 2 O 2 can be provided.In principle, however, the sterilization device provided on the transport path 5 can also operate with another substance or UV light.With regard to the first discharge device 8, an embodiment as a nozzle is particularly expedient. However, a liquid sterilant may also be spread in direct contact by a sponge, brush or the like.Within the scope of the invention, a particularly efficient sterilization of the entire container 1 is possible because reliable sterilization can also be carried out in the regions covered by the container receptacles 3 by the transfer of the sterilizing agent.List of reference numbers:1 Container 2 Starwheel 3 Container receptacles 4 Receiving region 5 Transport path 6 Dispensing region 7 Return path 8 First discharge device 9 Neck ring 10 Second discharge deviceReferences included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedEP 2 742 958 B1

[0007]

Claims

Method for sterilizing containers (1) with a revolving transport device having a plurality of container receptacles (3), wherein the containers (1) are received at a receiving region (4) by an associated container receptacle (3) in each case, transported with the container receptacle (3) along a transport path (5) and are discharged at a discharge region (6) from the associated container receptacle (3), characterized in that a sterilizing agent is applied to the unloaded container receptacles (3) at a return path (7) between the discharge region (6) and the feed region (4), wherein the sterilizing agent is at least partially transferred to the containers (1) which are received in the receiving region (4).Method according to claim 1, characterised in that a main sterilisation agent is applied to the containers (1) along the transport path (5) on an inner side of the container and / or an outer side of the container.Method according to claim 2, characterised in that the same substance is provided as sterilisation agent and main sterilisation agent.Method according to one of the preceding claims, characterized in that hydrogen peroxide is used as sterilisation agent.Method according to one of the preceding claims, characterized in that the containers (1) in the form of bottles or preforms made of plastic are held in the region of a neck ring (9) during their transport.Method according to one of the preceding claims, characterized in that the sterilisation agent is provided as a gas or mist on the return path (7) and condenses on the container receptacles (3) or precipitates on the container receptacles.Method according to one of the preceding claims, characterized in that the sterilizing agent is discharged preferably continuously as a vapor mixture of water vapor, hydrogen peroxide vapor and air at a vapor temperature between 110°C and 150°C, in particular about 120°C.Method according to one of the preceding claims, characterized in that the sterilisation agent is applied as a liquid to the container receptacles (3).Method according to claim 8, characterised in that the sterilisation agent is applied to a contact surface of the container receptacles (3) on the return path (7) at an area-specific quantity of 0.2 μl / cm 2( microliters per square centimeter) to 3 μl / cm 2.Method according to one of the preceding claims, characterized in that the container receptacles (3) are cooled before the sterilization agent is applied.Sterilisation system for carrying out the method according to one of the preceding claims, having a revolving transport device which has a plurality of container receptacles (3) and which has a receiving region (4) and a dispensing region (6) and is configured to receive containers (1) at the receiving region (4) each with an associated container receptacle (3), to transport them with the container receptacle (3) along a transport path (5) and to dispense them at the dispensing region (6), and wherein a return path (7) for the container receptacles (3) is provided between the dispensing region (6) and the receiving region (4), wherein a sterilisation device for the containers (1) is arranged at the transport path (5) and wherein a first discharge device (8) is provided at the return path (7) in order to apply a sterilisation agent to the container receptacles (3).Sterilization system according to claim 11, wherein the container receptacles (3) are designed as grippers.Sterilization system according to claim 12, wherein the grippers each have flat contact surfaces for the flat support of a neck ring (9).Sterilization plant according to one of claims 11 to 13, wherein the transport device has a starwheel (2) which carries the container receptacles (3).

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