Device with cleanroom for forming plastic preforms into plastic containers and plant for manufacturing plastic containers as well as method for forming plastic preforms into plastic containers

Abstract

Device (1) for forming plastic preforms (10) into plastic containers (20) with a transport device (2) on which a plurality of blowing stations (8) are arranged, wherein each of these blowing stations (8) has a blow mold within which a plastic preform (10) can be formed into a plastic container (20), wherein the device (1) has a cleanroom (6) within which the plastic preforms (10) can be transported, characterized in that the area of ​​the transport device (2) on which the blowing stations (8) are arranged is located in the cleanroom (6) and at least one further area of ​​the transport device (2) is located outside the cleanroom (6), wherein a stretching bar (5) for stretching the plastic preforms (10) is arranged at each blowing station (8) and this stretching bar (10) projects out of the cleanroom (6) at least temporarily and section by section.

Description

[0001] The present invention relates to a device for forming plastic containers. In the beverage manufacturing industry, it is known to use plastic containers, whereby these plastic containers are produced from plastic preforms by a forming process, and in particular a blow molding process. Blow molding wheels are typically provided, on which several blow molding stations are arranged. Within these blow molding stations, the plastic preforms are expanded against an inner wall of the corresponding blow mold by applying compressed air.

[0002] Many beverages require filling under aseptic conditions. It is well known that the sterilization process for aseptic filling begins with the sterilization of the finished bottles in a designated cleanroom. All prior processes, such as preform production, transport, heating, and blow molding to the bottle, take place in a non-sterile environment. In this case, it is necessary to sterilize a relatively large surface area, namely that of the finished plastic bottle.

[0003] Therefore, it is usually preferable to sterilize the plastic preform rather than the plastic bottle itself, as the latter has a significantly smaller surface area. However, after sterilization, the containers must be transported under sterile conditions, especially throughout, at least until they are sealed, to prevent further contamination of the containers.

[0004] EP 0 794 903 B1 describes a system and method for the sterile packaging of beverages. A beverage container is formed from a molded preform by blow molding, then the container is filled with a sterile beverage, and finally the filled container is filled with a sterilized closure cap. Different degrees of sterilization are controlled in different parts of the chamber, with the sterilization levels correlating with the degree required for the process step performed in the respective chamber part.

[0005] In this manufacturing process, the entire bottle production process, including the filling and closing processes, is carried out under sterile conditions. A complete container forming unit is also located in a clean room. This process ensures a high degree of sterilization and purity for the containers filled in this way. However, the sterilization effort is relatively high, as very large spaces must be kept sterile and numerous machine parts, particularly in the blow molding area, must be kept sterile.

[0006] DE 603 ​​09 244 T2 discloses a rotary-type filling device for filling containers under consistently sterile conditions. The filling device has a clean room for filling containers within the clean room. The filling device has filling stations, with a section of a filling nozzle being arranged within the clean room at each filling station, and with another section of the filling nozzle and the other elements of the filling device being arranged outside the clean room. The present invention is therefore based on the object of reducing the effort required to sterilize or maintain the sterile state of a forming unit or blow-molding device for containers. At the same time, however, the most sterile manufacturing conditions possible should be created for the containers.

[0007] This object is achieved according to the invention by a device having the features of claim 1, a system having the features of claim 12 and a method having the features of claim 15. Advantageous embodiments and further developments are the subject of the subclaims.

[0008] A device according to the invention for forming plastic preforms into plastic containers comprises a transport device on which a plurality of blow-molding stations are arranged. Each of these blow-molding stations has a blow mold within which a plastic preform can be formed into a plastic container. The device has a clean room within which the containers can be transported. According to the invention, the area of ​​the transport device where the blow-molding stations are arranged is located in the clean room, and another area of ​​the transport device is located outside the clean room.

[0009] Thus, in particular, the device according to the invention provides a clean room channel through which the plastic preforms or containers are guided in the blow molding stations, and another section of the transport device is moved outside the clean room. Thus, parts of the forming unit, such as a blow molding machine, e.g., the entire blow molding wheel or the blow molding cavities, are separated from the rest of the blow molding machine by a clean room or enclosed isolator.

[0010] Preferably, the transport device is a transport wheel that rotates around a predetermined axis, with at least the axis or one shaft of the transport device being located outside the cleanroom. This ensures that the cleanroom is kept as small as possible and thus also keeps the internal volume of the cleanroom to a minimum. Furthermore, this also ensures that as many machine parts as possible that are not in direct contact with the blow molding stations can be guided outside the cleanroom, thus minimizing contamination.

[0011] Preferably, the clean room has, at least in sections, an annular profile or a toroidal profile, although the cross-section of this toroidal profile preferably deviates from a circular shape. This means that the blow molding stations are guided by the transport device along a substantially circular path.

[0012] In a further advantageous embodiment, a stretching rod for stretching the plastic preforms is arranged at each blow molding station, and this stretching rod protrudes at least temporarily and in sections from the clean room. The stretching rod is known to be used to stretch the plastic preforms as part of the manufacturing process. In principle, it would also be possible to keep the entire stretching rod inside the clean room at all times. For this purpose, however, the clean room would have to be considerably enlarged in volume. In the preferred embodiment, it is therefore proposed that the stretching rod protrudes outwards through an opening in the clean room. To simultaneously prevent contamination of this stretching rod, it is particularly preferred to provide a bellows inside which the stretching rod runs, so that the stretching rod itself does not come into contact with the outside world. Sterile conditions therefore also prevail within the bellows.

[0013] Preferably, the clean room is delimited by several walls and at least one of these walls is arranged to be movable and in particular rotatable relative to another wall.

[0014] Preferably, a radially outwardly arranged wall of the cleanroom is arranged stationary. This allows a wall with a particularly cylindrical outer profile to be provided, which delimits the cleanroom. From the inside of this wall, a further wall is provided, which delimits the cleanroom to the other side and which is arranged so as to be rotatable. This inner wall is preferably rotated along with the individual blow molding stations. Preferably, the aforementioned rotatable wall and the stationary wall are opposite one another. Furthermore, the cleanroom is delimited by a wall in the form of a lid, wherein this lid is preferably formed integrally with the rotatable wall.

[0015] Preferably, a sealing device is arranged between at least two walls, or between a wall and a cover. This sealing device preferably seals off parts that are movable relative to one another. For example, it would be possible to provide a so-called water seal between a wall and a cover, in which a water channel, preferably annular in shape, is provided, in which a section of the part that is movable relative to this water channel is guided.

[0016] In a further advantageous embodiment, the device comprises a feed device for transferring the plastic preforms to the transport device, and this feed device is arranged within the clean room. Thus, the clean room preferably has a bulge or a deviation from the otherwise circular cross-section, and the feed device, such as a transport star for the preforms, is arranged in this bulge. In this way, a seamless transfer of the containers from the feed device to the transport device can take place within a sterile room.

[0017] In a further advantageous embodiment, the device also has a discharge device for receiving the formed plastic containers from the transport device, and this discharge device is also located within the clean room. In this way, a clean room can be maintained even during the removal of the containers. This makes it possible to insert preforms from upstream units into the isolator or clean room, and to remove the bottles to a subsequent unit, under clean room conditions. The isolator or clean room can be supplied with cleaning and sterilization media.

[0018] In a further advantageous embodiment, a sterile gas is provided within the cleanroom, and this sterile gas is at a pressure higher than the pressure outside the cleanroom. This allows the cleanroom to be optionally maintained at a higher pressure level than the ambient environment by introducing sterilized air, thereby preventing the penetration of microorganisms. Furthermore, it is possible to continuously supply an antimicrobial agent to the cleanroom, thus maintaining a hygienic environment.

[0019] A spatially confined cleanroom within the blow molding machine makes it possible to transport previously sterilized preforms to the filler without recontamination, both internally and externally, during the stretch blow molding process. Furthermore, the cleanroom is easier to maintain at a low-germ level than the entire forming machine.

[0020] The present invention is further directed to a system for producing plastic containers, which comprises a device for forming plastic containers of the type described above, as well as a heating device, wherein this heating device is arranged upstream of the above-mentioned device in a transport direction of the plastic preforms. This heating device serves to heat the preforms so that they can subsequently be expanded into containers in a blow molding process. Downstream of or after the forming device, a filling device is provided, which fills the containers with a beverage, in particular with an aseptic product. This filling device is also arranged in a clean room. Furthermore, the clean room preferably extends into the area of ​​a closing device, which closes the containers with a closure.

[0021] Furthermore, the system preferably comprises a sterilization device that sterilizes at least a portion of the plastic preforms before they reach the device. This sterilization can be carried out using a gaseous medium, such as, in particular, hydrogen peroxide. However, it would also be possible for the sterilization to be effected using radiation, such as electron beams and / or UV light. A sterilization device is preferably provided that also sterilizes, in particular, the inner surface of the plastic preforms. In addition, however, the outer surface of the plastic preforms can also be sterilized.

[0022] In a further advantageous embodiment, the system comprises an additional clean room arranged in the transport device for the plastic preforms upstream of the aforementioned device. This additional clean room preferably merges into the clean room of the forming device. In this way, it is possible to convey the plastic containers continuously from their sterilization to their closing, while still keeping the clean rooms required for this relatively small. Thus, the clean room is preferably provided as a channel extending from the sterilization device to the closing device, which is particularly preferably adapted to the corresponding blow molding stations or holding devices, such as gripping elements for the preforms or plastic containers.

[0023] The present invention is further directed to a method for forming plastic preforms into plastic containers, wherein the plastic preforms are transported by means of a transport device on which a plurality of blow-molding stations are arranged, and are formed into plastic containers during this transport. The blow-molding stations are transported at least partially and preferably completely through a clean room. According to the invention, at least one region of the transport device is arranged outside the clean room. More precisely, at least one region of the transport device is preferably also moved outside the clean room. In a further preferred method, the blow-molding stations are moved on a circular path and, particularly preferably, are continuously moved within the clean room.

[0024] Further advantages and embodiments can be seen from the attached drawings:

[0025] Showing: Fig. 1 a schematic representation of a plant for producing plastic containers; and Fig. 2 a view of a clean room in the area of ​​a blow molding station.

[0026] Fig. 1 shows a schematic representation of a system 50 for producing plastic containers 20. This system 50 has a heating device 30 in which plastic preforms 10 are heated. These plastic preforms 10 are guided through this heating device 30 by means of a transport device 34, such as a circulating chain in this case, and are heated in the process by a plurality of heating elements 31. This heating device 30 is followed by a transfer unit 36 ​​which transfers the preforms 10 to a sterilization device 32. This sterilization device 32 also has a transport wheel 37, and sterilization elements can be arranged on this transport wheel 37 or stationary. In this area, for example, sterilization by hydrogen peroxide gas or, as mentioned above, by electromagnetic radiation is possible. In particular, internal sterilization of the preforms is carried out in this area.

[0027] Reference numeral 6 denotes, in its entirety, a clean room, the outer boundaries of which are indicated here by the dotted line L. It can be seen that this clean room 6 begins in the area of ​​the sterilization unit 32. Locking devices can be provided in this area to introduce the plastic preforms into the clean room 6 without excessive gas loss within the clean room.

[0028] The cleanroom is adapted to the external design of the individual system components, as indicated by the dashed line L. This allows the volume of the cleanroom to be reduced.

[0029] Reference numeral 1 denotes, in its entirety, a device or a forming device in which a plurality of blow molding stations 8 are arranged on a transport wheel 2, only one of these blow molding stations 8 being shown here. These blow molding stations 8 expand the plastic preforms 10 into containers 20. Although not shown in detail here, not the entire area of ​​the transport device 2 is located within the clean room 6; rather, the clean room 6 or isolator is, in a sense, implemented as a mini-isolator within the entire device. Thus, it would be possible for the clean room 6 to be designed in a channel-like manner, at least in the area of ​​the forming device 1.

[0030] Reference numeral 22 refers to a feed device that transfers the preforms to the forming device 1, and reference numeral 24 to a discharge device that discharges the produced plastic containers 20 from the forming device 1. It can be seen that the clean room 6 has recesses in the area of ​​the feed device 22 and the discharge device 24, which accommodate these devices 22, 24. In this way, a transfer of the plastic preforms 10 to the forming device 1 or a takeover of the plastic containers 20 from the forming device 1 can be achieved in a particularly advantageous manner.

[0031] A transfer unit 42 transfers the expanded plastic containers 20 to a filling device 40, which is then removed from the filling device 40 via a further transport unit 44. The filling device 40 is also located within the aforementioned clean room 6. Even in the case of the filling device 40, it would be possible for not the entire filling device 40, including, for example, a reservoir for a beverage, to be located entirely within the clean room 6, but rather only those areas in which the containers are actually guided. In this respect, the filling device 40 could also be constructed in a similar manner to the device 1 for forming plastic preforms 10.

[0032] As mentioned, the cleanroom 6 is reduced to the smallest possible area in the area of ​​the device 1, namely essentially the blow molding stations 8 themselves. This compact design of the cleanroom 6 makes it easier and faster to construct a cleanroom 6, and maintaining sterility during operation is also less complex. Less sterile air is also required, which leads to smaller filter systems and also reduces the risk of uncontrolled vortex formation.

[0033] Fig. 2 shows a detailed view of the device 1 in the area of ​​a blow molding station 8. A plurality of such blow molding stations 8 are moved by a transport device 2 in a rotating manner about an axis X. The blow molding station 8 is, as in Fig.2, is guided within the clean room 6, which is designed as a channel here. This clean room 6 is enclosed by a movable side wall 16 and a cover 17 formed integrally with this side wall 16. This side wall 16 and the cover 17 rotate with the blow molding station 8.

[0034] Reference numeral 18 refers to a further wall that delimits the clean room 16. This wall 18 is an external wall 18 that is arranged in a stationary manner. Between the cover 17 and the wall 18, a sealing device 25 is provided, which seals the mutually movable elements 17 and 18 from one another, for example, as mentioned above, using a water seal. The lower region of the wall 18 is fixedly and sealingly arranged on a floor 13. Within the clean room 6 and here directly adjacent to the wall 16, a support 26 is provided, which also rotates and on which a holding device 23 is provided, which holds the blow molding station 8.

[0035] Reference numeral 11 refers to a follower device, which can be actuated by a guide cam 9 to open and close the blow-molding station 8 on its path through the clean room 6, in particular to insert the plastic preform 10 into the blow-molding station 8 and to remove it again. A guide cam 9 is also arranged within the clean room 6. However, it would also be possible, for example, to lead a section 19 out of the clean room 6 below the individual blow-molding stations 8.

[0036] The transport device 2 can have further elements which are arranged above the clean room 6.

[0037] The carrier 26 is fixedly arranged on a holding body 29 and this holding body 29 is in turn movable relative to the base 13. The reference numeral 27 refers to a further sealing device which also seals the mutually movable areas 13 and 29 in this area.

[0038] Reference numeral 5 refers to a stretching rod, which is movable relative to the blow molding station 8 in order to stretch the plastic preforms 10 in their longitudinal direction. A carriage 12 is arranged on the cover 17, relative to which the stretching rod 5 is movable in the direction Y. Reference numeral 14 refers to a further holder for this carriage 12 of the stretching rod 5.

[0039] It can be seen that certain areas of the stretch rod 5 are both outside the clean room 6 and inside the clean room 6 during the blow molding process. For this purpose, it is possible to provide a protective device 4, such as a bellows, outside the clean room 6 or above the carriage 12, which surrounds the stretch rod 5 so that no area of ​​the stretch rod 5 comes into direct contact with the outside environment.

[0040] All features disclosed in the application documents are claimed as essential to the invention, provided that they are new, individually or in combination, compared to the prior art.

Claims

[1] Device (1) for forming plastic preforms (10) into plastic containers (20) with a transport device (2) on which a plurality of blow-molding stations (8) are arranged, each of these blow-molding stations (8) having a blow mold within which a plastic preform (10) can be formed into a plastic container (20), the device (1) having a clean room (6) within which the plastic preforms (10) can be transported, characterized by that the region of the transport device (2) at which the blow-molding stations (8) are arranged is arranged in the clean room (6) and at least one further region of the transport device (2) is arranged outside the clean room (6), wherein a stretching rod (5) for stretching the plastic preforms (10) is arranged at each blow-molding station (8) and this stretching rod (10) protrudes at least temporarily and in sections from the clean room (6). [2] Device (1) according to claim 1, characterized by that the transport device (2) has a transport wheel which rotates about a predetermined axis (X), wherein at least the axis (X) is arranged outside the clean room (6). [3] Device (1) according to at least one of the preceding claims, characterized by that the clean room (6) has an annular profile at least in sections. [4] Device (1) according to at least one of the preceding claims, characterized by that this protruding section of the stretching rod is enclosed by a protective device (4). [5] Device (1) according to at least one of the preceding claims, characterized by that the clean room (6) is delimited by several walls (16, 17, 18) and at least one of these walls (16) is arranged rotatably relative to another wall (18). [6] Device (1) according to claim 5, characterized bythat a radially outwardly arranged wall (18) of the clean room (6) is arranged stationary. [7] Device (1) according to claim 5, characterized by that a radially inwardly arranged wall (16) of the clean room is movable. [8] Device (1) according to at least one of the preceding claims 5-7, characterized by that a sealing device (25) is arranged between at least two walls (17, 18). [9] Device (1) according to at least one of the preceding claims, characterized by that the device (1) has a feeding device (22) for transferring the plastic preforms (10) to the transport device (2) and this feeding device (22) is arranged within the clean room (6). [10] Device (1) according to at least one of the preceding claims, characterized bythat the device (1) has a discharge device (24) for receiving the plastic containers (20) from the transport device (2) and that this discharge device (24) is arranged within the clean room (6). [11] Device (1) according to at least one of the preceding claims, characterized by that a sterile gas is provided within the clean room (6) and that this sterile gas is under a pressure which is higher than a pressure outside the clean room (6). [12] Plant (50) for producing plastic containers (20) with a device (1) according to at least one of the preceding claims and with a heating device (30), wherein this heating device (30) is arranged on a transport direction (34) of the plastic preforms upstream with respect to the device (1). [13] System (50) according to claim 12, characterized bythat the system has a sterilization device (32) which sterilizes at least one region of the plastic preforms (10) before they reach the device (1). [14] Plant (50) according to at least one of the preceding claims, characterized by that the system (50) has a further clean room (6) which is arranged in front of the device (1) in the transport direction of the plastic preforms. [15] Method (1) for forming plastic preforms into plastic containers (20), wherein the plastic preforms (10) are transported by means of a transport device (2) on which a plurality of blow-molding stations (12) are arranged, and are formed into plastic containers (20) during this transport, wherein the blow-molding stations (8) are transported at least in sections through a clean room (6), characterized bythat at least one region of the transport device (2) is arranged outside the clean room (6), wherein a stretching rod (5) for stretching the plastic preforms (10) is arranged at each blow-molding station (8) and this stretching rod (10) protrudes at least temporarily and in sections from the clean room (6).

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