1. Technical Field
The present invention relates to a device and a method for treating at least one container, preferably for filling a container with a fill product in a beverage filling plant and/or for reshaping a container, for example for molding a preform into a container to be filled with fill product by stretch blow molding, wherein the treatment of the container takes place in an isolator chamber.
2. Related Art
For treating containers, and in particular for filling containers with a fill product, for example in a cold aseptic beverage filling plant, it is known to carry out the actual treatment of the containers inside a so-called isolator chamber. An isolator chamber is understood to mean a space sealed off from its surroundings in which a defined atmosphere is present, which is distinguished from the surroundings by having, for example, a reduced bacterial count, a reduced spore count, a reduced particle count, a defined temperature and/or a controlled humidity. Such an isolator chamber is typically fed with supply air which is prepared by a supply air preparation unit in order to achieve the desired atmosphere. In the supply air preparation unit, the air is for example cleaned using filter systems, brought to a defined humidity using suitable dehumidifiers or humidifiers, and brought to a defined temperature by suitable temperature control means.
For cold aseptic filling of beverages in a beverage filling plant, for example for filling containers with dairy products, it is necessary that at least in the filling area a certain temperature is not exceeded, and that the entry of bacteria and spores is reduced during filling. This can be achieved by controlling the air supplied to the isolator chamber, with the filling then being carried out inside the isolator chamber. It is possible to carry out in the isolator chamber not only the actual filling, but also, for example, sterilization of the containers to be filled and/or the closing of the filled containers, so that the defined environmental conditions can also be maintained for these treatments of the containers. The low bacterial and spore counts are of fundamental importance for the shelf life of the filled product. The lower the bacterial contamination of the filled product, the longer is its shelf life. The growth of bacteria can be further slowed by a reduced temperature in the isolator chamber.
Condensation of water from moist air can lead to increased growth of the microorganisms that are already present on the surfaces of the treatment device that the condensation moistens. Condensation can occur, for example, on filling valves, supply vessels or product feed lines, which are cooled by the flow of fill product or a separate cooling device, or on the cooled cavities of a molding tool when preforms are molded. This condensation must therefore be avoided in order to achieve hygienically acceptable treatment of the containers.
From the state of the art, it is known to supply the isolator chamber with prepared air via a central supply air preparation unit. This central supply air preparation unit normally takes in the air from the area surrounding the isolator chamber, for example from the production hall in which the device for treating the containers is installed. This ambient air is then treated by means of filters, dehumidifiers or humidifiers, and temperature control devices, then fed to the isolator chamber. The air is preferably then sucked out of the isolator chamber in a controlled manner, in order thereby to ensure a constant feed of prepared air, and to remove from the isolator chamber any particles which may have been introduced via the fill product or the container treatment process, and which are detrimental to the atmosphere in the isolator chamber, as well as for example disinfectant vapors. The extraction of disinfectant vapors may also be carried out for the protection of the operators of the plant.
The preparation of the supply air further serves to maintain a positive pressure in the isolator chamber with respect to the surroundings, in order to achieve the sealing off of the atmosphere in the isolator chamber. The extracted air is usually discharged into the open air.
In order to channel the containers that are to be treated into or out of the isolator chamber, at least one container channel is usually provided, for example in the form of an isolator intake or an isolator outlet, which serves as the transition between the surroundings and the isolator chamber. Accordingly, a transition from the ambient atmosphere to the defined atmosphere in the isolator chamber also takes place in the container channel. For this purpose the container channel is for example operated with a slight negative pressure, so that a constant flow of air occurs from the isolator chamber in the direction of the container channel, in order in this manner to prevent the ingress of ambient air into the isolator chamber via the container channel. The air sucked out of the container channel, which comprises a mixture of the air flowing from the isolator chamber and the air sucked in from the surroundings, is usually discharged into the open air.
Sterilization of the isolator chamber and those components of the plant that are located in the isolator chamber take place for example using gaseous H2O2, which is fed via the air supply to the isolator chamber, where it acts upon the applicable surfaces. The H2O2 is then sucked out of the isolator chamber and the container channel together with the other air in the isolator. For emission protection reasons, however, the H2O2 cannot be discharged directly into the open air, but must be elaborately scrubbed by means of a gas scrubber.
Since only ambient air is prepared in the supply air preparation unit, it is always necessary for 100% of the air that is fed to the isolator chamber to be prepared fully. The dimensions of the equipment used must therefore be correspondingly large.
When a preform is molded into a container to be filled with a fill product, for example by stretch blow molding, it is important for the quality of the container to be filled that condensation is avoided on the blow molds and in particular in the cavities of the tools. Since these cavities are usually cooled, they can be the site of condensation of moisture in the air, which impairs the quality of the molded containers and can also serve as the breeding ground for the multiplication of microorganisms that are already present. Here too, condensation should therefore be avoided.