Method and Device to Sterilise Containers

Abstract

Described and illustrated is a method to sterilise containers or receiving flowable foods; in a filling device. The method includes evaporating a hydrogen peroxide solution in an evaporator impinging at least one container with the vaporous hydrogen peroxide in a sterilisation zone and at least partially removing the unconsumed part of the vaporous hydrogen peroxide from the sterilisation zone. The removed vaporous hydrogen peroxide is at least partially condensed in a condenser and the condensed hydrogen peroxide is supplied to the evaporator.

Claims

1. A method to sterilise containers to receive flowable foods; in a filling device comprising: evaporating a hydrogen peroxide solution in an evaporator; impinging at least one container with the vaporous hydrogen peroxide in a sterilisation zone; removing, at least partially, an unconsumed part of the vaporous hydrogen peroxide from the sterilisation zone; condensing, at least partially, the removed vaporous hydrogen peroxide in a condenser; and supplying the condensed hydrogen peroxide to the evaporator.

2. The method according to claim 1, in which sterilised air is supplied to the sterilisation zone to preheat or to dry the at least one container, and in which the sterilised air is at least partially removed from the sterilisation zone with the vaporous hydrogen peroxide and is supplied to the condenser.

3. The method according to claim 1, in which an aqueous hydrogen peroxide solution is evaporated in the evaporator, in which the unconsumed part of the vaporous hydrogen peroxide and the water vapour are each at least partially removed from the sterilisation zone and are at least partially condensed in a condenser.

4. The method according to claim 1, in which the hydrogen peroxide is removed on the base side below a transport device to transport the at least one container through the device.

5. The method according to claim 1, in which the condenser is operated in such a way that a condensate has a higher or lower hydrogen peroxide concentration than the hydrogen peroxide solution before the evaporation.

6. The method according to claim 5, in which the condensate accruing in the condenser is adjusted to a predetermined hydrogen peroxide concentration between 25% by weight and 50% by weight and in which the hydrogen peroxide concentration of the concentrate is adjusted by thinning.

7. The method according to claim 5, in which the condensate accruing in the condenser is filtered to separate foreign matter or is supplied to an ion exchanger; for ion exchange.

8. The method according to claim 1, in which the at least one container is preheated with hot sterilised air in the sterilisation zone before the impinging with vaporous hydrogen peroxide, is dried with sterilised air after the impinging with the vaporous hydrogen peroxide, is filled with a flowable product after the impinging with the vaporous hydrogen peroxide, and is closed after the filling.

9. The method according to claim 1, in which a plurality of containers are transported through the sterilisation zone one after the other with the aid of a transport device having cells to receive individual containers.

10. The method according to claim 1, in which the container comprises a cardboard composite package.

11. A device to fill sterilised containers with flowable foods comprising: a sterilisation zone to receive at least one container, an evaporator to evaporate a hydrogen peroxide solution, a sterilisation device to impinge the at least one container with vaporous hydrogen peroxide in the sterilisation zone, and a removal device to at least partially remove the unconsumed part of the vaporous hydrogen peroxide from the sterilisation zone wherein a condenser is provided to at least partially condense the removed vaporous hydrogen peroxide and a supply unit is provided to supply the condensed hydrogen peroxide to the evaporator.

12. The device according to claim 11, wherein a filter device is provided to remove foreign matter from the condensate of the condenser, a thinning device is provided to thin a concentration of the condensed hydrogen peroxide to a predetermined concentration, a concentration device is provided to increase the concentration of the condensed hydrogen peroxide or a supply device is provided to replace non-condensed hydrogen peroxide.

13. The device according to claim 11, wherein a preheating device is provided to preheat the at least one container with hot sterilised air in the sterilisation zone, a drying device is provided to dry the sterilised container with sterilised air in the sterilisation zone, a filling device is provided to fill the sterilised container with food in the filling and sealing zone and a closing device is provided to close the filled containers in the filling and sealing zone.

14. The device according to claim 11, wherein a transport device having cells to receive individual containers is provided to transport a plurality of containers through the sterilisation zone and the filling and sealing zone one after the other.

15. The device according to claim 11, wherein at least one control device is provided to control or regulate evaporating a hydrogen peroxide solution in an evaporator; impinging at least one container with the vaporous hydrogen peroxide in a sterilization zone; removing, at least partially, an unconsumed part of the vaporous hydrogen peroxide from the sterilization zone; condensing, at least partially the removed vaporous hydrogen peroxide in a condenser; and supplying the condensed hydrogen peroxide to the evaporator.

16. The method according to claim 5, in which the hydrogen peroxide concentration is between 10% and 70% by weight.

17. The method according to claim 6, in which the hydrogen peroxide concentration is between 30% and 40% by weight.

18. The method according to claim 6, in which the hydrogen peroxide concentration of the concentrate is adjusted by thinning with water or by concentrating using a molecular sieve.

19. The method according to claim 7, in which the ion exchanger comprises a cation exchanger.

20. The device according to claim 14, wherein the transport device receives individual containers in a transport chain.

Description

[0038] The invention is explained in more detail below by means of drawings which only represent exemplary embodiments. In the drawings are shown

[0039] FIG. 1 a detail of a device according to the invention in a schematic depiction and

[0040] FIG. 2 a method according to the invention in a schematic depiction.

[0041] In FIG. 1, a detail of a device 1 to sterilise containers 2 in the form of a filling machine is depicted schematically. The depicted device 1 has an aseptic chamber 3 which comprises a sterilisation zone 3 a and a filling and sealing zone 3b through which a row of containers 2 in the form of packages are transported at least partially one after the other. The transport direction of the containers 2 therein points, as is symbolised by the arrows, from left to right, wherein the transport of the containers 2, however, does not have to occur in a straight line, but can also occur in an arc or even in a circle. The containers 2, in the form of packages, which in particular are cardboard composite packages having at least one cardboard layer, an aluminium layer and outer layers made from a thermoplastic plastic, in particular polyethylene (PE), are transported through the aseptic chamber 3 with the aid of a transport device 4 comprising a transport chain 5. For this purpose, the containers 2 in the form of packages are preferably initially each formed from a cut-to-size package by folding and partially welding or sealing the package material. The package base is thereby formed and closed. The head of the container remains open in order to be able to fill the container. The head of the container could, however, also be closed and the container could be filled through base which is still not closed.

[0042] The container 2 is preferably formed to be cuboidal and is passed to the transport device 4 in the form of a transport chain 5 after the forming. Fundamentally, the containers, however, can also have another form. For example, spherical or pyramidal containers are also possible. For this purpose, the transport device 4 has cells 6 into which the containers 2 in the not closed state, which can also be referred to as package blanks in the depicted embodiment, are introduced. The containers 2 or package blanks are then preferably held in a positive manner in the cells 6, such that on the one hand an easy introduction and removal of the containers 2 and on the other hand a defined transport with regard to the speed and the distance of the containers 2 between each other can be ensured. The infinite transport chain 5 is therein driven in a circle.

[0043] The transport device 4 is not sterile, such that the aseptic region of the filling and sealing zone 3b only reaches to the transport device 4, which, however, is sufficient for the sterile filling of a food in the filling and sealing zone 3b. In order to prevent a contamination of the containers 2 by the transport device 4, preferably a flow of sterilised air 7a is maintained from top to bottom in the aseptic chamber 3. For this purpose, corresponding sterilised air connections 8 are provided along the aseptic chamber 3 to supply sterilised air 7a. As a consequence of the sterilised air flow, no microorganisms can migrate from the transport device 4 upwards and settle at the upper end of the containers 2.

[0044] The sterilisation zone 3a and the filling and sealing zone 3b are separated in the depicted device 1 by a curtain of sterilised air which is blown upwards and flows downwards in a substantially laminar manner. Alternatively or additionally to the curtain, a sluice or a constriction would also be conceivable which just allows the containers into the filling and sealing zone 3b, but which at least tends to retain the atmosphere from the sterilisation zone 3a.

[0045] After the entry into the sterilisation zone 3a, the containers 2 are preheated by a preheating device 9 one after the other by blowing with hot sterilised air 7a. In a next station, the containers 2 are impinged with a mixture of water vapour, hydrogen peroxide and, preferably filtered, air 7 by means of a sterilisation device 10 which can be formed as a dosing device or can comprise a dosing device, in order to sterilise the containers 2. For this purpose, in the depicted and in this respect preferred device 1, an aqueous hydrogen peroxide solution 11 with a concentration between 30% by weight and 40% by weight, in particular of approximately 35% by weight, is evaporated on an electrically heated surface in an evaporator 12. The temperature of the vapour amounts to, in the depicted and in this respect preferred device 1, between 250° C. and 300° C., for example 270° C. The vapour is blown from a nozzle together with the filtered air 7 in order to lead the hydrogen peroxide evenly over the surface of the containers 2 to be sterilised. The filtered air 7 therein increases the total volume of the sterilisation gas which amounts, in the depicted and in this respect preferred device 1, to a concentration between 2% by volume and 10% by volume, in particular 2.5% by volume and 8% by volume. Therefore, a sterilisation of the containers 2 can be achieved with a low use of hydrogen peroxide. The hydrogen peroxide reacts on the surface of the container 2 with the microorganisms present there at temperatures between 150° C. and 270° C., in particular approximately 170° C. to 220° C., and thereby kills these.

[0046] After the sterilisation of the containers 2, these are dried by impinging with sterilised air 7a via a drying device 13 such that the hydrogen peroxide and condensed water are removed, before the containers 2 are subsequently filled with a food product, in the depicted and this respect preferred device 1 a drink, using a filling device 14. The filled containers 2 are then closed. In the depicted and in this respect preferred device 1, this occurs using a closing device 15 by folding the upper region of the package and sealing the corresponding region, wherein package sections which touch each other are welded to each other. The closed containers 2 are then transported from the aseptic chamber 3 by means of the transport device 4. Subsequently the containers 2 can be removed from the cells 6 of the transport device 4 one after the other.

[0047] At the lower end of the sterilisation zone 3a, underneath the transport device 4, the mixture of sterilised air, water vapour and vaporous hydrogen peroxide is removed via a suction box 16. The suction box 16 does not extend, in the depicted and in this respect preferred device 1, under the filling and sealing zone 3b. Therefore, the sterilised air is likewise not removed from the filling and sealing zone 3b, whereby the volume flow removed via the suction box would increase and the hydrogen peroxide concentration would decrease as a consequence of the corresponding thinning. The gas mixture can, for example, have a temperature of between 50° C. and 80° C., in particular between 60° C. and 70° C. The removed gas mixture is then supplied to a condenser 17 in which the water and the hydrogen peroxide are partially condensed. The condenser can be a tube bundle heat exchanger having several tube registers. It is therein preferred if the individual tube registers each operate in the cross-flow and are each flowed through with coolant in series as well as in counter-flow to the gas mixture to be condensed. The gas mixture to be condensed is therein guided in a zigzagged manner from bottom to top through the individual tube registers. Therein, the composition of the gas mixture over the gas flows supplied to the sterilisation zone 3a and/or the at least one temperature of the condenser 17 is selected such that the concentration of the hydrogen peroxide in the condensate 18 amounts to approximately between 30% by weight and 35% by weight. Fundamentally, however, other concentrations can also be expedient, such as for example at least 15% by weight, at least 20% by weight or at least 25% by weight, as well as for example at most 70% by weight, at most 50% by weight or at most 40% by weight.

[0048] The condensate 18 is subsequently supplied to a conditioning device 19 in which the condensate 18 is freed from dust and/or other particles from the sterilisation zone 3 in a filter device 20 having a filter made from sintered polyethylene. To clean the filter, this can be periodically backwashed.

[0049] The thus cleaned condensate 18 is supplied to an adjustment device 21 to adjust the desired hydrogen peroxide concentration, said adjustment device 21 comprising, in the depicted and in this respect preferred device 1, a thinning device 22 and a concentration device 23. The thinning device 22 has a supply 32 of, preferably demineralised, water in a storage container 24, in which the condensate 18 from the condenser 17 can be thinned by addition of water. The hydrogen peroxide concentration is thereby preferably adjusted to a value between 30% by weight and 40% by weight, in particular approximately 35% by weight. The concentration device 23 comprises at least one absorption unit 25 comprising molecular sieves for the absorption of water which is driven out again from the molecular sieves in a separate step. The concentrated hydrogen peroxide solution can be led back into the storage container 24. The conditioning of the hydrogen peroxide solution occurs intermittently and in batches.

[0050] The hydrogen peroxide solution with the adjusted concentration is guided from the storage container 24 to an intermediate storage 27 in which further hydrogen peroxide solution is supplied through a supply device 28 to compensate for the consumed hydrogen peroxide and the hydrogen peroxide contained in the gas phase 25 leaving the condenser 17. This preferably occurs via a hydrogen peroxide solution of predetermined concentration which can correspond to the concentration which is adjusted in the storage container 24.

[0051] Additionally, in the depicted and in this respect preferred device 1, surfaces of the device 1 which come into contact with hydrogen peroxide can consist of steel of material number 1.4404 or 1.4571 (each V4A), of polyethylene (PE), of polypropylene (PP) or of glass. Alternatively, the contact surfaces can be passivated and/or heated. Incidentally, the temperature of the hydrogen peroxide solution between the condenser 17 and the evaporator 12 can be kept from a temperature level of less than 50° C. in order to prevent an evaporation of hydrogen peroxide. Alternatively or additionally, organic and/or inorganic stabilisers can be added to the hydrogen peroxide solution which can also be evaporated and/or leave the evaporator 12 as aerosols. In the depicted and in this respect preferred device 1, pumps are provided to convey the condensate 18 from the condenser 17 to the intermediate storage 27 and furthermore to the evaporator 12. These pumps 29 can form a supply unit or be a part thereof. Alternatively or additionally, the conditioning device 19 can also completely or partially part of the supply unit. The same applies for corresponding tube lines or similar which have previously not been referred to in detail, but can be gleaned without any problems from FIG. 1. Additionally, a removal device 30 is provided to remove water vapour, vaporous hydrogen peroxide and sterilised air from the sterilisation zone 3a or the suction box 16. A further pump 31 is provided to operate the concentration device 23.

[0052] The method to operate the previously described device 1 is depicted schematically as a block flow diagram in FIG. 2. Therein, the method steps occurring in the aseptic chamber or in direct connection with the aseptic chamber are arranged in a frame A representing the aseptic chamber. The processing steps with regard to a container B are arranged vertically one below the other. Initially, the application of the container B to the transport unit which assumes the transport of the container B through the aseptic chamber A occurs. Then the supply of the container B into the sterilisation zone SZ occurs. In the sterilisation zone SZ, the preheating of the container B with hot sterilised air occurs; the sterilised air is initially produced from roughly purified air L by filtering the same. The sterilised air is also blown into the aseptic chamber A at further points.

[0053] After the preheating of the container B, the sterilisation of the preheated container B occurs with a mixture of roughly purified air, water vapour and vaporous hydrogen peroxide. In a further step, the sterilised container B is transferred into the filling and sealing zone FS and there is filled with a food from a store. Subsequently, the container B is closed and is sealed in a sealing station by ultrasonic welding. The thus sealed container is then guided away from the aseptic chamber A with the aid of a transport device. Then a separation of the completed container B from the transport device occurs.

[0054] The contained gas mixture G of water vapour, vaporous hydrogen peroxide and sterilised air is removed from the sterilisation zone SZ and supplied to a condenser. The condensate K and a gas phase P leaves the condenser, said gas phase being removed, in the depicted and in this respect preferred device, as an exhaust gas. The gas phase P contains, besides the air removed from the sterilisation zone SZ, further residue of water vapour and hydrogen peroxide. The condensate K is passed into a conditioning device E, symbolised by a frame, in which a filter device is provided, which filters the condensate K in order to separate solids. Subsequently the purified condensate reaches a storage container to condition the purified condensate, in particular to adjust the hydrogen peroxide concentration of the condensate. The concentration of the hydrogen peroxide in the condensate can be reduced via a thinning device by means of the addition of, in particular demineralised, water. Alternatively or additionally, the hydrogen concentration of the condensate is increased by the water of the condensate being partially separated and indeed preferably just to the extent that the desired hydrogen peroxide concentration can be provided. The correspondingly conditioned hydrogen peroxide solution is then replenished and dispensed to an intermediate storage, from which the hydrogen peroxide solution can be continuously supplied to the evaporator. Consumed hydrogen peroxide can be replaced in the intermediate storage by addition of a fresh hydrogen peroxide solution H of suitable concentration of hydrogen peroxide. The concentration of the fresh hydrogen peroxide solution therein corresponds approximately to the concentration of the conditioned condensate which is supplied to the intermediate storage. The condensate is supplied to the evaporator again to sterilise further containers.