|Title of Invention||
METHOD FOR STERILIZING CONTAINERS
|Abstract||A method is disclosed for sterilising bottles, cans or similar containers by introducing H2O2 in the form of vapour or a hot H2O2 sterilisation medium into each container during an application phase, and by activating the H2O2 sterilisation medium in an activation phase by introducing a hot, sterile activation medium in the form of a gas and/or vapour into each container, preferably by introducing hot sterile air into each container.|
Method for sterilizing containers
The invention refers to a method for sterilizing containers in accordance with the generic term in patent claim 1 as well as to a sterilization device according to the generic term in patent claim 14.
Methods for sterilizing bottles, cans or such containers using hydrogen peroxide (H202) containing sterilization medium, i.e. using a sterilization medium (below also H202-sterilization medium), which contains hydrogen peroxide in a mixture with hot sterile air, are known (DE 10 2004 030 956 A1, DE 19949 692 A1, WO 2006/053745 A1). In these methods, which are used for example for sterilizing containers for beverages, in addition, for sterilizing containers or packing for other products, for example, medicines, an H2O2 condensation film is formed in case of application of hot H202-sterilization medium at the inner surface of the cooler container by condensation, which is then activated in an activation phase following it by applying a sterile hot gas and/or vaporous activation medium, for example by applying hot sterile air in the manner that free oxygen radicals result from decomposition of H2O2, which react with germs and contaminants present for the sterilization of the containers.
It is also known in these methods (DE 10 2004 030 956 A1), to heat up sterile air used as activation medium to activation temperature by the fact that it is conveyed by a heat exchanger heated to a temperature between 130 °C and 150 °C. In a process step following the activation phase, then blowing and a cooling of the containers takes place with the sterile air, which is supplied to the container with a temperature distinctly below the activation temperature. The sterile air is conducted by the heat exchanger for this purpose with a corresponding high flow rate, which prevents a heating to the activation temperature.
Further, methods and devices (EP 0 590 505 A1, DE 19846 322 A1) are known for treatment of bottles or such containers with a hot treatment medium, which is introduced
into the containers. The temperature of the containers before and after the thermal treatment and the temperature of the backflow treatment medium is recorded with the help of temperature sensors and among other things the temperature of the hot treatment medium and/or the intensity of the treatment is controlled depending on the measured temperatures. A treatment with a hydrogen peroxide containing treatment medium is not intended.
The task of the invention is to document a method and a device, with which by maintaining a high sterilization rate, i.e. a high quality of the sterilization, the duration of the total treatment and particularly also the duration of the activation phase can be reduced, and precisely in case of careful treatment of the containers. In order to find a solution to this task, a method is developed according to the patent claim 1. The device is developed according to the claim 14, whereby the following dependent claims document different embodiments.
A substantial reduction of the process duration and thereby particularly the total period of the activation phase are achieved with the method and the device according to the invention. At the same time, a treatment avoiding a slight and a thermal overload of the containers take place with high quality of the sterilization and with high sterilization rate. The method according to the invention is therefore suitable in particular for containers made of plastic, e.g. from PET.
Further developments of the invention are the object of the sub-claims. The invention is described in the following paragraphs in detail with figures of an embodiment.
Fig. 1 very simplified representation and plan view of a machine and a device for
executing the process according to the disclosure;
Fig. 2 simplified representation of a treatment head of the device of the Figure 1.
The device for sterilization of bottles indicated generally with 1 in the figures and the method shows a rotor 2 rotating around a vertical machine axis, which can be driven, for application of the sterilization devices in the bottles 3 to be treated, which are supplied by means of a container intake star 4 and from there the treated, i.e. the moistened bottles 3 are removed over a container discharge 5 and supplied to the subsequent activator. The activator is a rotor 6 drivable around the vertical machine axis for activating the sterilization medium by means of sterile heating air, which is conducted into the bottles 3 to be treated. The bottles 3 are supplied to the rotor 6 by means of a container intake star 7 and the treated, i.e. sterilized bottles 3 are removed over a container discharge 8 and supplied to the subsequent process step, usually a filler.
Application heads are provided above each bottle opening in known manner at the rotor 2, which rotate with the rotor 2 and are indicated only as double, broken lines I. Each application head at the rotor 2 is assigned a bottle or a container support 14, at which
the respective bottle 3 is held below the treatment head 6 during the treatment and precisely in the said embodiment, bottles 3 developed as PET bottles, suspended at a bottle-side orifice flange.
The wetting of the surfaces of the bottles 3 takes place using the H2O2 - sterilization medium, which is heated in known manner within the respective treatment head by injecting hydrogen peroxide, for example by 35%-hydrogen peroxide into sterile air and by heating the aerosol obtained in such a manner up to a temperature Ti of, for example, 145°C.
Hot H2O2 -sterilization medium is introduced into the bottle 3 for the treatment in such a manner that H2O2 -condensation film is formed by condensation at the colder inner surface of the bottle 3 compared to the temperature T1 of the H202-sterilization medium; the condensation film covers uniformly at least the total inner surface of the respective bottle 3 with a H2O2 -condensation.
Following this application phase and after the transfer of the moistened bottles to the rotor 6 in such a manner, an activation of the H202-condensation film takes place in a further treatment phase, i.e. in an activation phase. For this purpose, activator heads 9 are provided similar to the construction and arrangement at the rotor 2 above each bottle opening in known manner, which rotate with the rotor 6 and are indicated only in Fig. 1 as double, broken lines II. The activation is started by energy input and precisely by introducing a hot sterile gas- and/or vaporous medium, for example, by introducing hot sterile air with a temperature T2 into the respective bottle 3 and precisely through a pipe 10 inserted into this bottle (Fig. 2). A decomposition reaction of H202 takes place with this activation, in the course of which, among other things, free oxygen radicals are obtained, which react with germs and/or contaminants present in the respective bottle 3 and effects their sterilization. At the same time, a drying of the respective bottle 3 also takes place with the hot sterile air used in the activation phase. Sterilization methods with these process steps are in principle known.
The method according to invention differs in relation to known methods by a special arrangement of the individual treatment phases and their process steps.
In the application phase, the hot H202-sterilization medium is introduced with a constant temperature Ti and with a constant discharge- or application time, for example, with a discharge time of 3 sec in bottles or containers with a volume of 500 ml. The flow rate V, of the hot H202-sterilization medium introduced into the respective bottle 3 is thereby constant, for example, during the application time.
The activation of the H202 condensation film in the respective bottle 3 takes place during the activation phase in two process-/activation steps. During a first process step, the hot sterile air with a temperature T2 with a constant, large flow rate V2 used for
activation is introduced by means of the pipe 10 (Fig. 2) into the bottle 3. This introduction takes place for example over a specified delivery period of x seconds, or however until the temperature of the tank wall TBW of the respective bottle 3 has attained a specified desired temperature SOII-TBW, which is measured and monitored by means of a pyrometer 11 (Fig. 2). The dash-dotted arrow 12 outlines the measuring procedure. The total period of this first process step is approx. 8 to 10 seconds.
In a subsequent further process step, the hot activation medium, which is preferably again a hot sterile air, with the temperature T3 and with a flow rate V3 is introduced into the bottle 3, and precisely over a delivery time of y seconds. The temperature of the flow rate V3, which is usually equal or also less than the flow rate V2, is lowered thereby depending on the tank temperature TBW of the respective bottle 3, so that also during this second process step of the activation phase, the container temperature TBW exhibits the desired temperature Soll-TBw and remains below a maximum permissible value. T3 is thus less than T2 and is adjusted by means of a heat exchanger and the admixture of cold sterile air or cold inert gas, like C02 or N2.
The desired temperature Soll-TBW lies thereby in both process steps below a temperature, which would lead to an excessive load or deformation or to a damage of the bottles 3.
The tank temperature TBW is also measured in the second process step without contact using at least a pyrometer 11. As suggested in the Figure 2, other contactless heat measuring systems can also be used depending on the construction of the rotor 6 and the activator head as well as the tank material associated with it. In the variation shown in Fig. 2, the pyrometer 11 is mounted as swivel-type, in order to be able to align optimally depending on the bottle- or tank geometry.
Since the temperature of the bottle wall is monitored, such a steep heating gradient and temperature in the second activation phase can be selected, which was not adjustable in known units for safety reasons (deformation of the bottle).
The advantages of the method according to the invention consist, among other things, of the fact that the activation proceeds much vigorously and can be held at very high level, so that a substantial shortening of the duration of treatment is possible, i.e. a shortening below 10 seconds is obtained. In particular, in the larger range of capacity, i.e. with higher output of the unit exhibiting the device 1 (number of treated bottles 3 per time unit), in which hitherto an additional, second activator retrofitted to the rotor 6 was required, now the activation phase can alone be carried out at the rotor 6 or the rotor 6 can exhibit a clearly lower diameter, if two activation rotors are to be provided. This also means that a substantial increase in machine output is possible with reduced machine expenditure. In special cases, the application phase and the activation phase are carried out at one single rotor.
Since the method according to invention is based on an automatic regulation at least of the flow rate V3 of the activator gas to be cooled by means of direct or indirect cooling in the second process step of the activation phase, time-consuming settings or experiments are not required for the operator of a unit to achieve an optimal sterilization of bottles or such containers. The respective unit can be controlled and operated without problems using manufacturer data, which consider different tank forms and/or materials, whereby the activation phase and the process steps there are carried out or controlled automatically by the unit internal control system.
In another embodiment of the sterilization device according to the invention, not represented here, cooling collars are provided at rotor 6 (activator rotor), which at least partly and at least occasionally enclose the tank to be treated during the activation. The cooling collar does not rest thereby or only in joint faces at the tank surface, so that an annular gap or channels are formed between containers and collar in the intended operation, through which a gas or a liquid can flow. Thereby, the collars are ideally so designed that this exhibits at least one opening, which is connected with a pipeline path and a gas conveying device, over which a gaseous and/or liquid medium can be conducted in the annular gap or the channels for cooling of the reservoir wall. Alternatively, cooler room- or ambient air can be conducted in the annular gap or the channels by means of the opening and suitable pipeline paths and vacuum pumps for cooling the tank wall and then discharge. Very fast a safety cooling can take place with such a cooling collar or the time lag of the temperature control can be shortened.
The substantial parameters of an embodiment of the method according to the invention for sterilizing bottles 3 with a volume of 500 ml can be summarized as follows:
H2O2 -concentration in the H2O2 -sterilization medium: 20% maximum tank temperature
TBW: approx. 35°C - 42 °C
Temperature Ti: approx. 145°C
Pressure of the H202-sterilization medium: approx. 0.7 bar
Flow rate V1. approx. 1.5 l/bottle
Flow rate v-i: approx. 2.7 Nm3/h
Activation phase - process step 1 maximum tank temperature TBW: approx. 67 Temperature T2: approx. 145°C
Flow rate V2: approx. 10.8 l/bottle
Steam pressure: approx. 1.0 bar
Air pressure: approx. 1.5 bar
Activation phase - process step 2
Tank temperature TBw'- approx. 67 °C - 68 °C
Flow rate V3 approx. 10.8 l/bottle approx. 9.7 Nm3 / h
Temperature T2 The treatment periods for each activation phase are less than 10 s, whereby the treatment periods x and y can be different, but also same. Further, it is possible to plan for example a treatment interval of approx. 4 to 5 s between the application phase and the activation phase i.e. the first process step of the activation phase is then initiated with a time delay of approx. 5 seconds after introducing the H2O2 -sterilization medium and after the conclusion of the application phase.
The invention was described earlier with an embodiment. It is clear that numerous changes as well as modifications of the features of the present invention are possible without deviating from the spirit and scope of the underlying inventive concept. Thus, it was assumed that the treatment heads 6 are part of a design rotating around the treatment machine or device. Of course, the method according to the invention can also be carried out on units, which are designed as linear machines. Further, it was assumed that the introduction of H202-sterilization medium and introduction of the activation medium take place over the same treatment head 6. Of course, different treatment heads can also be used in these process steps.
1. Method for the sterilization of bottles, cans or such containers (3) by introducing a hot H202-sterilization medium into the respective container(3) in an application phase as well as by activating the H2O2- sterilization medium in an activation phase by introducing a sterile gas and vaporous hot activation medium, preferably by introducing hot sterile air into the respective container(3), wherein the activation phase has at least two activation steps and at least in the chronologically final activation step the temperature of the flow rate (V3) of the activation medium supplied to the respective container (3) is controlled depending on the container temperature (TBw) or the temperature of the wall of the container (3).
2. Method according to claim 1, wherein the temperature control takes place by indirect cooling of the flow rate (v3) of the second activation phase.
3. Method according to claim 1 or 2, wherein the temperature control takes place by direct cooling of the flow rate (v3) of the second activation phase, by adding a controlled flow rate (v4) at cooler gas to the flow rate (v3) and the gas is particularly taken from the group: sterile air, C02, N2, noble gases or a mixture of these.
1. A method for sterilizing bottles, cans or similar vessels (3) by introducing either
vaporous H2O2 or a hot H2O2 sterilization medium in a particular vessel (3) in an
application phase, as well as by activating the H202 sterilization medium in an
activation phase by introducing a sterile gaseous and/or vaporous activation medium
and by introducing hot, sterile air in a particular vessel (4), where the activation
phase features two procedural steps, characterised in that,
at least during part of the activation phase the volume flow rate (v2, v3) of the activation medium introduced into the particular vessel (4) is regulated, depending on either the vessel temperature (TBw) or the temperature of the wall of the vessel (3), where the volume flow rate (v3) of the activation medium directed into the particular vessel is regulated, depending on the vessel temperature (TBw), in the chronologically last activation step, and that the vessel temperature (TBw) is measured with no contact, where the volume flow rate (V3) in the second activation phase is less than the volume flow rate (v2) in the first activation phase.
2. The method as claimed in claim 1, wherein the volume flow rate (v3) in the second activation phase amounts to only 40-60% of the volume flow rate (v2) in the first activation phase.
3. The method as claimed in claim 1 or 2, wherein the volume flow rate (v2, v3) is regulated so the vessel temperature (TBw) corresponds to the set-point temperature
4. The method as claimed in claim 1, 2 or 3, wherein the vessel temperature (TBw) is
measured with a pyrometer.
5. The method as claimed in any one of the preceding claims, wherein the volume flow rate (v2) of the activation medium directed into the particular vessel (3) is regulated in the chronologically first procedural step, depending on the vessel temperature (TBW)-
6. The method as claimed in any one of the preceding claims, wherein the activation phase features two procedural steps and the activation medium is directed to the particular vessel (3) in a time-controlled manner during the chronologically first step at a constant temperature (T2) or at a roughly constant temperature and at a constant or roughly constant volume flow rate (v2).
7. The method as claimed in any one of the preceding claims, wherein the hot sterilization medium is directed to the particular vessel (3) in a time-controlled manner at a constant or roughly constant temperature (Ti).
8. The method as claimed in any one of the preceding claims, wherein the hot sterilization medium is directed during the application phase into the particular vessel (4) at a constant or roughly constant temperature and over a constant or roughly constant period of time at a volume flow rate (V1) that, taking into account the vessel temperature (TBw), is so staged or driven that the vessel temperature (TBw) remains well below the temperature (V1) of the hot H2O2 sterilization medium.
9. The method as claimed in any one of the preceding claims, wherein the hot H2O2 sterilization medium is fed during the application phase with application lasting 2.5 -4 seconds.
lO.The method as claimed in any one of the preceding claims, wherein the duration of treatment in an activation step is less than 10 seconds.
11.The method as claimed in any one of the preceding claims, wherein the activation phase is carried out on a single activator.
12.A sterilization device for vessels such as bottles, mugs, cans and the like for conducting the method in any of the claims 1-11, wherein at least a device for no-contact measurement of solid surface temperatures and a computerized control and regulating device connected therewith to regulate temperature and/or volume flow rate is shown, where the steps in at least two activation phases are independent of each other and are feasible on a single transport device, while at least a throttle, a valve or the like is arranged to regulate the volume flow rate of the activation medium in routing the activation medium to an activator head (9), where devices for no-contact measurement of solid surface temperatures are arranged on or near at least a fraction of the activator head (9) and where a device for no-contact measurement of solid surface temperatures is arranged on or in the vicinity of the activator head (9).
13.The sterilization device as claimed in claim 12, wherein at least one device for no-contact measurement of solid surface temperatures is a pyrometer.
Title: Method for Sterilizing Containers
A method is disclosed for sterilising bottles, cans or similar containers by introducing H2O2 in the form of vapour or a hot H2O2 sterilisation medium into each container during an application phase, and by activating the H2O2 sterilisation medium in an activation phase by introducing a hot, sterile activation medium in the form of a gas and/or vapour into each container, preferably by introducing hot sterile air into each container.
|Indian Patent Application Number||2585/KOLNP/2009|
|PG Journal Number||10/2014|
|Date of Filing||14-Jul-2009|
|Name of Patentee||KHS GMBH|
|Applicant Address||JUCHOSTRASSE 20, 44143 DORTMUND|
|PCT International Classification Number||AA61L2/20; B65B55/10; A61L2/20|
|PCT International Application Number||PCT/EP2008/003247|
|PCT International Filing date||2008-04-23|