Abstract:
The invention relates to a device and a method for producing containers, such as e.g. bottles, in which different types of bottles are produced. Alternative treatment methods are used depending on the type of bottle to be produced. For example, a cooling treatment is carried out when producing bottles for carbonated beverages and a sterilisation treatment is carried out when producing bottles for non-carbonated beverages.

Description:
FIELD OF THE INVENTION 
     The invention relates to a device and a method for producing plastic containers. The device for producing plastic containers is preferably a machine from the pharmaceutical or food technology sector. Such machines and methods are used mainly for the production and pre-treatment of containers, such as bottles, cans, stand-up pouches or vials. Containers made from plastic, in particular from PET, are preferably produced, treated, filled and closed. 
     BACKGROUND OF THE INVENTION 
     Such machines for producing, treating and filling containers are widely known from the prior art. For example, WO 2006 00 3304 A1 discloses a machine for producing and filling PET bottles, wherein the containers are treated by cooling the bottom thereof between the production process and the filling process. EP 1 572 540 B1 discloses a device and a method for sterilizing containers, wherein the sterilization depends on certain environmental parameters. 
     Such machines for sterilizing packagings are of a relatively complex design. This complex design has the disadvantage that such machines are not very flexible with regard to the containers to be produced. Therefore, while it is relatively easy for a container production machine, such as e.g. for a stretch-blowing machine, to be adjusted to different types of container to be produced, it is much more difficult for the treatment unit to react in a flexible manner to different container requirements. One disadvantage of the prior art is that different installations are required for containers for different foodstuffs, such as e.g. bottles for carbonated beverages and bottles for non-carbonated beverages. This is very expensive and very complicated. 
     SUMMARY OF THE INVENTION 
     The object of the present invention is therefore to provide a method and a device by means of which containers with different requirements can be produced in a simple and flexible manner. 
     The device for producing plastic containers is preferably an installation for producing, treating and filling the containers. The containers are preferably made from plastic, in particular from PET. They are preferably produced from preforms made from plastic, which are heated in a first step and then in a second step are formed by means of a blowing process, in particular a stretch-blowing process, to form the desired containers. The container treatment station is preferably a device through which the containers are transported on their way from the container production machine to the filling machine. The transporting of the containers through this device may take place in various ways; for example, transport on a conveyor belt or in a transport chain is conceivable, which holds the containers at the container bottom or in the region of the container body and/or container neck. According to one preferred embodiment of the invention, the containers are transported through the container treatment station by means of star wheels. The star wheels may grip the containers at various points; transport or gripping in the region of a carrier ring is preferably possible. This has the advantage that the containers are guided through the container treatment station at a fixed distance from one another, so that the upstream and downstream machines can be driven synchronously with one another. One advantageous mode of operating this installation is the block mode. 
     The container treatment station preferably comprises a plurality of treatment units, in the region of which a treatment can take place. The units can be selectively activated or deactivated by a control system. Corresponding activation or deactivation of the individual units takes place as a function of the containers to be produced. For example, if containers for carbonated beverages are to be produced, these will have different requirements with regard to their properties than containers for non-carbonated beverages. In order to be able to set these different mechanical and/or optical properties of the containers, a different treatment is required following the production of the containers in the blowing machine. Such a difference in the treatment may be, for example, the rapid cooling of the container bottom after production of the container. 
     Preferably, the container treatment station comprises, as different types of units, cooling and/or heating and/or sterilization and/or cleaning and/or decorating units. Other types of units are also conceivable in order to ensure a production of containers that is as flexible as possible. The decorating units are for example labelling units. In the sterilization unit, the treatment is preferably carried out using sterilization media in liquid or vapour form. 
     Since, according to one preferred further development of the invention, a sterilization of the containers produced is to be possible, it is advantageous that at least part of the container treatment station forms a chamber which is closed off from the ambient conditions. Preferably, the entire container treatment station is designed as a clean room. 
     The treatment station may be of various types. For example, it is possible both that the treatment units remain stationary and the containers are moved through the units during transport, and that the units move and have the same path at least during part of the movement of the containers through the container treatment station. Furthermore, it is conceivable that the units are arranged in such a way as to produce closed treatment chambers in the container treatment station, in which certain processes take place. For instance, it is possible that spray nozzles for sterilization media are arranged in the wall of the container treatment station and/or of a unit, which nozzles cover a certain area and thus spray containers at certain locations as they are transported. However, it is also conceivable that smaller closed units are formed, so that e.g. treatment tunnels are formed. These may be completely or partially closed off from the surroundings, i.e. from the container treatment station. 
     In the case of containers to be treated which have an opening only at one end, the star wheels themselves may also be designed as treatment stations. One preferred further development of the invention consists in that in each case at least one nozzle is arranged in the transport star wheels above the mouth of the containers to be transported and treated, which nozzle can introduce treatment media into the containers. Via such nozzles, hydrogen peroxide or peracetic acid can be introduced as sterilization media into the containers. These nozzles arranged above the mouths are preferably designed in such a way that they rotate in the region of the respective transport star wheel in a manner fixedly assigned to the containers. Preferably, they are arranged in a height-adjustable manner so that the nozzle or at least a part thereof protrudes at least partially into the container during the introduction of treatment medium. This arrangement has the advantage that the treatment medium can be metered very precisely in terms of both the consumption and the location to be treated. 
     Preferably, the device has for each treatment unit a stationary distributor which may be arranged either inside or outside the housing of the container treatment station. The distributor is connected on the one hand to a treatment medium supply and on the other hand to the treatment units. Since the distributor preferably has a stationary part and a rotating part, a direct coupling both to the stationary treatment medium supply and to the rotating transport star wheels is possible. Arranged in the region of the distributor is at least one evaporator which can evaporate the liquid sterilization or cleaning medium. 
     The method for producing plastic containers comprises at least the steps of production of the containers, intermediate treatment and filling of the containers, wherein the intermediate treatment takes place temporally between the production process and the filling process. According to one preferred embodiment of the invention, a sterilization of the containers is carried out in at least one treatment unit, wherein an external and/or internal treatment takes place. An internal treatment of the container preferably takes place by introducing a sterilization medium directly into the bottle via the mouth thereof, since this results in a consumption of media that is as low and as targeted as possible. A droplet from a nozzle into the container is just as conceivable as a spraying of the sterilization medium. It is also possible to carry out an external treatment of the container, wherein here preferably at least one dedicated sterilization tunnel is provided. A sterilization tunnel has the advantage that the space around the container to be sterilised can be kept as small as possible, so that the consumption of sterilization medium is minimised. 
     A sterilization or cleaning may be carried out by a sterilization medium in liquid and/or gaseous and/or vapour form, wherein hydrogen peroxide is used as the preferred medium. This has the advantage that good sterilization can be achieved in low sterilization times. If liquid hydrogen peroxide is used, evaporators are preferably provided, by means of which it is possible for sterilization medium in vapour form to be introduced into the containers. The sterilization is preferably carried out at a point in time during the treatment method at which the containers still possess a residual heat. This residual heat allows a dry sterilization using sterilization medium in vapour form, without the latter condensing. The use of the residual heat is particularly advantageous since a dry sterilization is particularly desirable in order to facilitate the removal of residues of the sterilization medium. However, other sterilization media are also conceivable, 
     In order to be able to make optimum use of the “non-condensation” of the sterilization medium in the container treatment station, it is possible that a temperature equalisation in the container wall is carried out by targeted cooling or heating in at least one treatment and/or transfer star wheel. To this end, relatively hot or cold air for example can be blown into the container or can be blown onto the outer wall thereof. As a result, the temperature distribution can be homogenised. 
     Instead of sterilization, it is also possible to carry out a cleaning and/or disinfection of the, containers using the method and device according to the invention. A cleaning and/or disinfection of the container outer wall may be carried out for example using sterile water. 
     According to one preferred further development of the invention, the transporting of the containers in the container treatment station takes place by means of transport star wheels, wherein the intermediate treatment preferably takes place during transport. Preferably, at least two different types of transport star wheels are located in the container treatment station, namely treatment star wheels on the one hand and transfer star wheels on the other hand. The transport star wheels may have identical or different diameters. Preferably, the treatment star wheels have a larger diameter than the transfer star wheels, and the main treatment steps take place there. Preferably, a sterilization of the interior of the containers takes place in the treatment star wheels and a sterilization of the container outer wall takes place in the transfer star wheels. The container cooling is preferably accommodated in the transfer star wheels, with such a treatment also being possible in the treatment star wheels. 
     Containers with different properties, preferably with different mechanical properties, can be produced using the method according to the invention. It is possible for example to produce containers for carbonated or non-carbonated beverages. Due to their different compositions and effects on the containers and also different sensitivity levels, different containers and/or different treatments during the production of the finished products are required. For example, containers with a stable bottom are required for the filling of carbonated beverages, since otherwise the container bottom may curve outward and the container may be unable to stand upright. For such a stable container, it is advantageous if the container bottom is cooled as soon as possible after production of the container. The cooling gives rise to a “freezing” of the molecular structure at the appropriate point in time, as a result of which an increased stability is achieved. 
     Such a stable packaging is not required for the filling of non-carbonated beverages; instead, the aim in this case is to introduce as few germs as possible into the bottle to be filled, in order to achieve a sufficient shelf life. A particularly clean or in some cases even sterile/low-germ filling of such beverages is therefore necessary. Therefore, when non-carbonated beverages are packaged according to the invention, only the units required for cleaning and/or sterilization are activated. The other units remain inactive, with transport but no treatment taking place. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The method according to the invention and the device according to the invention will be explained in more detail with reference to the figures, in which: 
         FIG. 1  shows a plan view of a device for producing plastic containers, 
         FIG. 2  shows a plan view of a container treatment station, 
         FIG. 3  shows a section through a treatment unit, 
         FIG. 4  shows a section through another treatment unit, 
         FIG. 5  shows an isometric view of a container treatment station. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  shows a container production machine  1  which comprises a preform sorting and supply device  23 , an oven  22  and also a stretch-blowing machine  24 . The preforms are fed from a storage device (not shown here) to the preform sorting device  23  and are transported via a supply system to the oven  22 , where they are brought to a certain orientation temperature. The oven  22  may be an infrared heating oven or a microwave oven. From the oven  22 , the heated preforms are handed over via the inlet star wheel  25  to the blowing wheel  27 . The blowing wheel has a plurality of blow moulds (not shown here), into which the preforms are blown by means of compressed air. The bottles which have then been blown are picked up by the outlet star wheel  26  and handed over to a hand-over star wheel  10   a  which closes the transfer gap between the outlet star wheel  26  and the first transfer star wheel  10  of the container treatment station  2 . By way of example, the hand-over star wheel  10   a  may be used as a temperature equalisation star wheel in order to bring zones of different temperature in the interior of the bottle to an approximately uniform surface temperature. To this end, for example, temperature-controlled sterile air at a defined temperature may be blown by rotating nozzles through the mouth towards the container bottom, which then transfers heat from hotter zones to zones with a low temperature level. 
     Both the outlet star wheel  26  and the following star wheels, such as e.g. the hand-over star wheel  10   a , the transfer star wheels  10  and the treatment star wheels  9  grip the bottles in each case in the mouth region. A closed transport of the blown bottles at the mouth of the bottles is thus ensured at least from the outlet star wheel  26  to the outlet of the container treatment station  2 . Within the container treatment station  2 , the containers  50  are transported through the treatment units in a manner suspended from the mouth region. From the outlet of the container treatment station  2 , the treated containers  50  are handed over to the container filling machine  3  and a filling process is carried out. After this filling process, the containers are closed in a closing device  28 , wherein the closing device  28  is supplied with cleaned, disinfected or sterilised closures from the closure disinfection device  29 . The closure disinfection device  29  is a module for disinfecting closures by means of hydrogen peroxide, wherein other disinfection methods, such as e.g. by means of liquid peracetic acid, are also conceivable. 
     After the containers have been closed, said containers are handed over to a container onward transport device  30 , which may comprise either a conveyor belt or a neck handling system. 
       FIG. 2  shows a plan view of the container treatment station  2 , which is connected via a hand-over star wheel  10   a  to the container production machine  1 . 
     The entire container treatment station  2  is accommodated in a housing  20 , so that the atmosphere within the container treatment station  2  can be substantially closed off from the atmosphere outside. It is therefore possible to establish defined ambient conditions within the container treatment station  2 . 
     The hand-over star wheel  10   a , which is accommodated in an airlock  21 , is located upstream of the container treatment station  2  in the transport direction so that it is possible to transfer the produced containers from the container production machine  1  to the container treatment station  2 . 
     The container treatment station  2  itself has a plurality of transport star wheels  8 , of which four are designed as treatment star wheels  9 ,  9 ′,  9 ″,  9 ′″ and four are designed as transfer star wheels  10 ,  10 ′,  10 ″,  10 ′″. The containers  50  always run through all the transport star wheels  8  during their treatment in the container treatment station  2 , even if a treatment is provided only in certain treatment or transfer star wheels  9 ,  10 . At the end of the container treatment station  2 , the containers  50  are handed over by an inlet star wheel  25 ′ to the container filling machine  3 . 
       FIG. 3  shows a cross section through the treatment star wheel  9 . The treatment star wheel  9  comprises a central star wheel column  33  which is secured in a carrier plate  32 . The carrier plate  32  forms part of the basic machine frame of the container treatment station  2  and is located in the external atmosphere, i.e. not in the treatment area. The delimitation of the treatment area as seen from the bottom up starts with the table surfaces  31  and  31 ′. These are preferably at an angle with respect to one another, so that there is a downward gradient towards the outer edge of the container treatment station  2  in order to be better able to transport away any liquids and dirt. The star wheel column  33  has tangential supports  34  which can move in the direction of rotation B. Attached to the end of the tangential supports  34  are neck grippers  18  which grip the containers  50  below or above the carrier ring in the region of their mouth. 
     Arranged in the table surfaces  31  and  31 ′ are cam holders  35 , at the upper ends of which two control cams  16 ,  16 ′ are arranged. Control rollers  36  run between the lower control cam  16  and the upper control cam  16 ′, which control rollers are connected to nozzle holders  37 . In each case a tangential support  34  with an associated neck gripper  18  is fixedly assigned, relative to the rotary position, a nozzle holder  37  with an attached control roller  36  and a rotating nozzle  11 . A height movement of the rotating nozzles  11  relative to the container  50  results on account of the control cam  16 ,  16 ′ and the control roller  36 . 
     The rotating nozzles  11  are designed in a bell shape so that they have a diameter larger than the mouth diameter of the containers  50  to be treated. In this way, the rotating nozzles  11  can be placed over the mouth of the containers  50 . The rotating nozzles  11  have an application tube  38 , by means of which treatment media (e.g. sterile air, hydrogen peroxide) can be introduced into the containers  50 , and they are equipped at the top with connecting lines  19  which lead to a distributor  12 . When a treatment medium is introduced via the application tube  38  into the containers  50 , firstly the container interior is filled with the treatment medium. If more treatment medium is fed into the containers  50  than their volume accommodates, an overflowing of the containers  50  with treatment medium results on account of the bell-shaped design of the rotating nozzles  11 , so that at the same time an external disinfection/external cleaning takes place. 
     The distributor  12  forms the connection piece between the star wheel column  33  and the housing  20  of the container treatment station  2 . The distributor  12  has a stationary part  15  and a rotating part  17 . Treatment medium is supplied to the container treatment station  2  through the stationary part  15 . As already mentioned above, the rotating part  17  is connected via flexible connection lines  19  to the rotating nozzles  11 , so that the treatment medium can pass from the distributor  12  via the connection lines  19  and the rotating nozzles  11  into the containers  50 . 
       FIG. 4  shows a further treatment unit of the container treatment station  2 , namely a sterilization unit, in particular a sterilization tunnel  14  which is arranged around the transfer star wheel  10 ′ over part of its circumference so that the containers  50 , during transport along the transfer star wheel  10 ′, are at least partially located in an atmosphere that can be substantially closed off from the surroundings. The transfer star wheel  10 ′ also has a star wheel column  33  with tangential supports  34  attached thereto and neck grippers  18  attached at the end of the latter. The neck gripper  18  grips the container  50  below or above the carrier ring in the region of the mouth. The sterilization tunnel  14  has perpendicular side walls  39  and also a bottom wall  40  and a top wall  41 . The bottom wall  40  is arranged in a V-shaped manner, so that there is a downward gradient from the side walls  39  to the centre of the bottom wall  40 . The side walls  39  and the bottom wall  40  enclose an intermediate space  42 , in which a treatment medium is located. The treatment medium can pass through the openings  52  from the intermediate space  42  into the interior of the sterilization tunnel  14 , where the container  50  is located. In this way, a uniform treatment of the container  50  over its entire surface is possible. Preferably, a sterilizing/disinfecting/cleaning treatment of the exterior of the container  50  is carried out by the sterilization tunnel  14 . Such a treatment medium of the sterilization tunnel  14  may be e.g. hydrogen peroxide. 
       FIG. 5  shows a container treatment station  2  in an isometric view, wherein the containers  50  are transported from the right-hand half of the figure to the left-hand half of the figure. The containers  50  are again transported via a container production machine  1  (not shown here) and the hand-over star wheel  10   a  through the airlock  21  into the container treatment station  2 . Each treatment star wheel  9 ,  9 ′,  9 ″,  9 ′″ and the transfer star wheel  10 ′ is assigned a media supply. For instance, a media supply  101  is assigned to the treatment star wheel  9  and its distributor  12 . A media supply  102  is assigned to the transfer star wheel  10 ′, a media supply  103  is assigned to the treatment star wheel  9 ′, a media supply  104  is assigned to the treatment star wheel  9 ″ and a media supply  105  is assigned to the treatment star wheel  9 ′″. The media supplies  101 ,  102 ,  103  and  104  also have an evaporator  13  in each case. The media supplies  101  to  105  in each case open into the distributors  12  assigned to the transport star wheels  8 . 
     The media supplies  101 ,  102  and  103  additionally have lines  106 , through which hydrogen peroxide can be metered upstream of the respective evaporators  13 . Through the media supplies  101  to  103 , sterile air is mixed with hydrogen peroxide by opening the valves  107 , so as to provide a sterilizing treatment medium in vapour form which is mixed with air. If the valves are not opened, only a treatment with sterile air takes place. 
     The container treatment station  2  is designed in such a way that a treatment with hydrogen peroxide can be carried out in the treatment star wheels  9 ,  9 ′ and in the transfer star wheel  10 ′ and a rinsing with sterile air can be carried out in the treatment star wheels  9 ″ and  9 ′″. In the transfer star wheel  10 , a cooling treatment by a nitrogen nozzle  112  can take place by introducing liquid nitrogen into the containers  50 . A double-headed nozzle is preferably located in the transfer star wheel  10 , so that in each case two containers  50  can be supplied with nitrogen in an alternating manner or simultaneously. In this case, only every second container in each case is supplied with nitrogen by a nitrogen nozzle  112 . 
     The sterilization and cooling treatments preferably take place on an alternative basis. If a container is cooled by means of liquid nitrogen in the transfer star wheel  10  after it has been produced, the treatment star wheels  9  and  9 ′ are supplied not with hydrogen peroxide but rather only with sterile air. As a result, although a rinsing of the containers  50  with sterile air takes place, no sterilization with hydrogen peroxide is carried out. On the contrary, in the event of a sterilization of the containers by supplying hydrogen peroxide in the treatment star wheels  9  and  9 ′, no cooling is carried out by supplying liquid nitrogen in the transfer star wheel  10 . The treatment star wheel  9 ′″ has just one air supply  110 , so that always only rinsing with air is carried out here in all the alternative treatment methods. Depending on the treatment method, the other treatment star wheels  9 ,  9 ′ and  9 ″ can be used either for sterilization or only for rinsing, depending on which treatment variant is required in each case. 
     The supply device for the hydrogen peroxide is located on a pedestal  111 . This has the advantage that the periphery for providing the hydrogen peroxide is easily accessible for repair or maintenance tasks.