PASTEURIZATION PLANT HAVING AN ION EXCHANGE DEVICE AND METHOD OF OPERATING A PASTEURIZATION PLANT

Abstract

The invention relates to a pasteurization plant and a method of operating a pasteurization plant. During operation of the pasteurization plant, a tempered process liquid is applied to containers filled with food products in one or more treatment zone(s). At least a part of the process liquid is fed back to the treatment zone(s) for reuse in at least one recirculation loop. At least a partial quantity of a volumetric flow of the process liquid fed per unit of time via the at least one recirculation loop is diverted to create at least one partial flow, circulated through at least one cleaning device and then returned to a recirculation loop or a treatment zone again. The at least one cleaning device comprises a membrane filtration device and an ion exchange device.

Claims

1. Method of operating a pasteurization plant (1), comprising conveying containers filled with food products and closed (6) through one or more treatment zone(s) (2), treating the containers (6) with a tempered aqueous process liquid (4) in the treatment zone(s) (2) by applying the process liquid (4) to an external surface (5) of the containers (6), wherein at least a part of the process liquid (4) from the treatment zone(s) (2) is fed back to a treatment zone (2) for reuse in at least one recirculation loop (11), and wherein at least a partial quantity of a volumetric flow of the process liquid (4) fed per unit of time via the at least one recirculation loop (11) is diverted to create at least one partial flow (19), which at least one partial flow (19) is filtered by means of a membrane filtration device (23), and dissolved ions are then removed from the at least one partial flow (19) by means of an ion exchange device (24) having at least one strongly acidic cation exchanger (32), and the at least one partial flow (19) is then returned to a recirculation loop (11) or a treatment zone (2) again.

2. Method according to claim 1, wherein a pH value of the partial flow (19) is influenced means of the at least one strongly acidic cation exchanger (32) with a view to obtaining a desired pH level.

3. Method according to claim 1, wherein the at least one strongly acidic cation exchanger (32) is regenerated depending on a change in pH value of the partial flow (19).

4. Method according to claim 1, wherein anions are removed from the partial flow (19) by means of at least one strongly basic anion exchanger (33).

5. Method according to claim 4, wherein a pH value of the partial flow (19) is influenced by means of the at least one strongly basic anion exchanger (33) with a view to obtaining a desired pH level.

6. Method according to claim 4, wherein the at least one strongly basic anion exchanger (33) is regenerated depending on a change in pH value of the partial flow (19).

7. Method according to claim 1, wherein a content of ions dissolved in the partial flow (19) is monitored by sensors upstream and downstream of the ion exchange device (24) respectively.

8. Method according to claim 7, wherein a content of ions dissolved in the partial flow (19) is monitored by measuring a pH value of the partial flow (19) respectively upstream and downstream of the point where ions are removed by means of the ion exchange device (24).

9. Method according to claim 1, wherein the partial quantity of process liquid (4) diverted from the at least one recirculation loop (11) in order to create the partial flow (19) is regulated by means of a flow regulating device (35).

10. Method according to claim 1, wherein at least a part of the process liquid (4) removed from the partial flow (19) by means of at least one flow regulating means (38) is fed through the ion exchange device (24) and then returned to the partial flow (19) again.

11. Method according to claim 10, wherein a flow quantity of process liquid (4) through the ion exchanger(s) (32, 33) is regulated respectively by means of a flow regulating means (38) separately for each ion exchanger (32, 33) of the ion exchange device (24).

12. Method according to claim 1, wherein before removing the dissolved ions, the partial flow (19) is additionally directed through a liquid treatment device (42) comprising metal particles or a metal mesh comprising copper and/or zinc.

13. Method according to claim 1, wherein after removing dissolved ions, dissolved substances are also removed from the partial flow (19) by means of an adsorption device (43).

14. Method according to claim 13, wherein the dissolved substances are removed from the partial flow (19) by means of an activated carbon filter (44).

15. Method according to claim 1, wherein the food products in the containers (6) are heated in a treatment zone (2) or are heated in several treatment zones (2) successively and then pasteurized in a treatment zone (2) or several treatment zones (2),, after which they are cooled in a treatment zone (2) or cooled in several treatment zones (2) successively.

16. Method according to claim 1, wherein a partial volumetric flow of process liquid (4) is directed through a heat exchanger (46) of an air-cooled cooling tower (45), depending on requirements.

17. Method according to claim 1, wherein containers (6) incorporating a metal material, in particular an aluminum material, can be treated by means of the pasteurization plant (1), at least temporarily.

18. Pasteurization plant (1), comprising one or more treatment zone(s) (2) with delivery means(n) (3) for applying a tempered process liquid (4) to an external surface (5) of containers (6), a conveyor device (7) for conveying the containers (6) through the treatment zone(s) (2), and at least one recirculation loop (11) for diverting the process liquid (4) from the treatment zone(s) (2) and for recirculating at least a part of the diverted process liquid (4) to a treatment zone (2), wherein at least one cleaning device (16) is provided, which at least one cleaning device (16) is fluidically connected to a removal means (17) for removing a partial flow (19) of process liquid (4) from the at least one recirculation loop (11), and which at least one cleaning device (16) is connected to a returning means (18) for returning the partial flow (19) to a recirculation loop (11) or a treatment zone (2), which at least one cleaning device (16) comprises a membrane filtration device (23) for filtering the partial flow (19), and which at least one cleaning device (16) comprises an ion exchange device (24) having at least one strongly acidic cation exchanger (32) fluidically connected downstream of the membrane filtration device (23).

19. Pasteurization plant according to claim 18, wherein the ion exchange device (24) comprises at least one strongly basic anion exchanger (33).

20. Pasteurization plant according to claim 18, wherein the ion exchange device (24) is fluidically connected to at least one regeneration means (40, 41) for regenerating the ion exchanger(s) (32, 33).

21. Pasteurization plant according to claim 18, wherein a sensor means for monitoring a content of ions dissolved in the partial flow (19) is arranged fluidically upstream and downstream of the ion exchange device (24) respectively.

22. Pasteurization plant according to claim 21, wherein a pH value sensor (34) is arranged fluidically upstream and downstream of the ion exchange device (24) respectively.

23. Pasteurization plant according to claim 19, wherein a ratio of an ion exchange total capacity of all the available strongly acidic cation exchangers (32) to an ion exchange total capacity of all the available strongly basic anion exchangers (33) is selected depending on requirements with a view to obtaining a desired pH value of the partial flow (19) or process liquid (4).

24. Pasteurization plant according to claim 18, wherein a flow regulating device (35) is assigned to the at least one cleaning device (16).

25. Pasteurization plant according to claim 18, wherein the ion exchange device (24) is arranged fluidically parallel with a flow line (39) for the partial flow (19) in the at least one cleaning device (16) via at least one flow regulating means (38).

26. Pasteurization plant according to claim 25, wherein every ion exchanger (32, 33) of the ion exchange device (24) is assigned a flow regulating means (38).

27. Pasteurization plant according to claim 18, wherein the at least one cleaning device (16) comprises another liquid treatment device (42) comprising metal particles or a metal mesh comprising copper and/or zinc, which liquid treatment device (42) is fluidically connected between the membrane filtration device (23) and the ion exchange device (24).

28. Pasteurization plant according to claim 18, wherein the at least one cleaning device (16) comprises an adsorption device (43), which adsorption device (43) is fluidically connected downstream of the ion exchange device (24).

29. Pasteurization plant according to claim 28, wherein the adsorption device (43) has an activated carbon filter (44).

30. Pasteurization plant according to claim 18, wherein it comprises an air-cooled cooling tower (45) having a heat exchanger (46) through which the process liquid (4) can be guided if necessary.

Description

[0086] These are highly simplified, schematic diagrams respectively illustrating the following:

[0087] FIG. 1 a schematic diagram illustrating one example of an embodiment of a pasteurization plant;

[0088] FIG. 2 a schematic diagram illustrating one example of an embodiment of a cleaning device of the pasteurization plant;

[0089] FIG. 3 a detail of a schematic diagram illustrating parts of an example of another embodiment of the pasteurization plant.

[0090] Firstly, it should be pointed out that the same parts described in the different embodiments are denoted by the same reference numbers and the same component names and the disclosures made throughout the description can be transposed in terms of meaning to same parts bearing the same reference numbers or same component names. Furthermore, the positions chosen for the purposes of the description, such as top, bottom, side, etc., relate to the drawing specifically being described and can be transposed in terms of meaning to a new position when another position is being described.

[0091] FIG. 1 schematically illustrates an example of an embodiment of a pasteurization plant 1. The pasteurization plant 1 comprises one or more treatment zone(s) 2 with delivery means 3 for applying a process liquid 4 to an external surface 5 of containers 6. In the embodiment illustrated as an example in FIG. 1, 5 treatment zones 2 are illustrated by way of example but it goes without saying that it would also be possible to provide more or fewer treatment zone(s) 2 depending on the requirements and design of a pasteurization plant 1.

[0092] Food products are pasteurized during operation of the pasteurization plant 1 and the containers 6 are firstly filled with the food products and the containers 6 are then closed. The containers 6 filled with the food products and then closed are treated in a respective treatment zone 2 by applying an aqueous process liquid 4 to an external surface 5 of the containers 6 via the delivery means 3. The delivery means 3 of a respective treatment zone 2 may be provided in the form of sprinkler or nozzle type sprying means or generally means for distributing the process liquid in a respective treatment zone 2. The tempered aqueous process liquid 4 is applied to the external surface 5 of the containers 6 in this manner so that the containers 6 and hence the food products packaged in the containers 6 can be tempered in a specific way and pasteurized. In principle, containers 6 incorporating a metal material, in particular containers 6 incorporating an aluminum material, can be at least intermittently treated by means of the pasteurization plant 1.

[0093] In order to convey the containers 6 through the treatment zone(s) 2, a conveyor device 7 is provided. In the embodiment illustrated as an example in FIG. 1, the conveyor device 7 comprises two driven conveyor belts 8 by means of which the containers 6 which have been filled with food products and closed are conveyed through the treatment zone(s) 2 on two levels during operation of the pasteurization plant 1. This may be done from left to right, for example, in a conveying direction 9 indicated by arrows in FIG. 1.

[0094] During operation of the pasteurization plant 1, the food products in the containers 6 can be heated first of all in a treatment zone 2 or in several treatment zones 2. In the embodiment illustrated as an example in FIG. 1, the food products and containers 6 can be successively heated in the two treatment zones 2 illustrated on the left-hand side in FIG. 1, for example. After heating, the food products can be pasteurized in a treatment zone 2 or several treatment zones 2, for example by applying a process liquid 4 appropriately tempered for pasteurization purposes in the treatment zone 2 illustrated in the center in FIG. 1. The food products and containers 6 can then be cooled in a treatment zone 2 or in several treatment zones 2. The containers 6 can be successively cooled by applying a process liquid 4 at a temperature suitable for cooling purposes in the two treatment zones 2 illustrated on the right-hand side in FIG. 1.

[0095] For example, the food products are heated in treatment zone 2 disposed first of all in the conveying direction 9 and are then further heated in the next treatment zone 2 disposed in the conveying direction 9. In the next treatment zone 2 disposed in the conveying direction 9, the food products can then be pasteurized by applying a process liquid 4 at a particularly high temperature, for example between 70 C. and 110 C., to the external surface 5 of the containers 6. In the next two treatment zones 2 disposed in the conveying direction 9, the food products and containers 6 can then be cooled in a specific manner using an appropriately tempered cooler process liquid 4. The main advantage of this is that the food products are pasteurized as gently as possible, in particular without the tempering process itself causing damage to the food products.

[0096] After applying the tempered process liquid 4 to the external surface 5 of the containers 6 in the treatment zone(s) 2, the process liquid can be collected in a bottom floor region 10 of a respective treatment zone 2 and fed back out of a respective treatment zone 2. In order to discharge the process liquid 4 from the treatment zone(s) 2 and return at least a part of the discharged process liquid 4 to a treatment zone 2 or to one of the treatment zones 2, the pasteurization plant 1 comprises at least one recirculation loop 11. During operation of the pasteurization plant 1, therefore, at least a part of the process liquid 4, preferably a predominant part of the process liquid 4 or the entire process liquid 4, is fed out of the treatment zone(s) 2 for reuse in this at least one recirculation loop 11 and back into a treatment zone 2 again.

[0097] As may be seen from the embodiment illustrated as an example in FIG. 1, the process liquid 4 is fed out of a treatment zone 2 via a recirculation loop 11 and fed into another treatment zone 2, for example. In the embodiment illustrated as an example, the process liquid 4 is fed out of the treatment zone 2 shown on the far left-hand side via a recirculation loop 11 and into the treatment zone 2 shown on the far right-hand side, for example. Conversely, the process liquid 4 can be fed out of the treatment zone 2 shown on the far right-hand side via a recirculation loop 11 into the treatment zone 2 shown on the far left-hand side for heating the containers 6 and food products, for example. This may be of particular advantage because the process liquid 4 is cooled or heated accordingly whilst it is being applied to and is acting on the containers 6. Due to this cooling and/or heating, the process liquid 4 from one respective treatment zone 2 may therefore be at a suitable temperature for another treatment zone 2. Alternatively, it may also be of advantage if the process liquid 4 from a treatment zone 2 is fed via a recirculation loop 11 back into the same treatment zone 2, as may be seen in the case of treatment zone 2 illustrated in the middle in FIG. 1 which is used to pasteurize the food products.

[0098] In order to convey and/or direct respective volumetric flows of process liquid 4 in the recirculation loop 11 or in the recirculation loops 11, conveying means 12 may be respectively provided, for example pumps, as illustrated in FIG. 1. Furthermore, the pasteurization plant 1 is provided with means 13 for discharging parts of the process liquid 4 from the recirculation loop 11 and/or out of the recirculation loops 11, for example for sampling purposes, and means 14 for feeding in substances such as fresh process liquid 4, for example fresh water, or chemicals, etc.. Such means 13, 14 might be provided in the form of pipes, for example, which are run so as to feed process liquid 4 into and/or out of collection tanks, etc., or which means 13, 14 are fluidically connected to heating and/or cooling devices for the purpose of tempering process liquid. A heating device 15 is illustrated by way of example in FIG. 1, for example a steam heater or a heat pump, which heating device 15 is fluidically connected via means 13, 14 to the recirculation loop 11 in order to return process liquid 4 to the centrally illustrated treatment zone 2. In this manner, the process liquid for this recirculation loop 11 can be respectively heated to the temperature needed for the process of pasteurizing the food products.

[0099] Due to the continuous circulation of the process liquid 4 via the recirculation loop 11 or recirculation loops 11 and/or the continuous reuse of the process liquid 4 during operation of the pasteurization plant 1, contaminants and/or undesired substances can get into the aqueous process liquid over time. To enable these undesired substances and/or contaminants to be continuously removed from the process liquid 4, at least one cleaning device 16 is provided. The at least one cleaning device 16 is fluidically connected to a removal means 17 for removing a partial flow 19 of process liquid 4 from the at least one recirculation loop 11. The at least one cleaning device 16 is also fluidically connected to a returning means 18 for returning the removed partial flow 19 to a recirculation loop 11 or a treatment zone 2. As a result, during operation of the pasteurization plant 1, at least a partial quantity of a volumetric flow of process liquid 4 circulated via the at least one recirculation loop 11 per unit of time can be diverted to create at least one partial flow 19, as indicated by the arrows in FIG. 1.

[0100] In the embodiment illustrated as an example in FIG. 1, two cleaning devices 16 are illustrated by way of example, which cleaning devices 16 are fluidically connected to different recirculation loops 11 respectively. Naturally, it would also be possible to provide only one cleaning device 16 or a pasteurization plant 1 may also have more than two cleaning devices 16. The number and also the cleaning capacity of cleaning device(s) 16 will be selected and/or set respectively taking account of the size and treatment capacity of a respective pasteurization plant 1 amongst other things. Furthermore, it would also be perfectly possible to provide several cleaning devices 16 fluidically connected via removal means 17 to a recirculation loop 11 and/or to one of the recirculation loops 11.

[0101] In principle, a removal means 17 may be a simple distribution element, for example having a T-piece 20 which enables a partial flow 19 to be diverted from a recirculation loop 11, as schematically illustrated in FIG. 1. A returning means 18 may comprise a pipe, for example, by means of which a cleaned partial flow 19 can be returned to a treatment zone 2, as illustrated by way of example in FIG. 1. To make allowance for and/or compensate the pressure loss across the at least one cleaning device 16, the partial flow 19 may be returned to a pipe of a recirculation loop 11 via another T-piece for example, as an alternative to the embodiment illustrated as an example in FIG. 1. Other elements may also be provided, such as control means 21 and/or shut-off means 22, for example to enable a partial quantity of process liquid 4 diverted and/or removed from a volumetric flow in a recirculation loop 11 to create a partial flow 19 to be influenced and/or regulated, and/or to enable a cleaning device 16 to be shut off from a recirculation loop depending on requirements. Examples of such other elements will be explained in more detail with reference to FIG. 2.

[0102] As also illustrated in FIG. 1, the at least one cleaning device 16 comprises a membrane filtration device 23 for filtering the removed partial flow 19. The at least one cleaning device 16 further comprises an ion exchange device 24 fluidically connected downstream of the membrane filtration device 23, which ion exchange device 24 has at least one strongly acidic cation exchanger. Conveying means 25 are provided to enable the at least one diverted and/or removed partial flow 19 to be circulated through the at least one cleaning device 16.

[0103] As a result, during operation of the pasteurization plant 1, the at least one partial flow 19 removed or diverted from a recirculation loop 11 can be filtered by means of a membrane filtration device 23 and dissolved ions can then be removed from the at least one partial flow 19 by means of an ion exchange device 24 having at least one strongly acidic cation exchanger. Having been cleaned in this manner, the at least one partial flow 19 can then be returned via a returning means 18 to a recirculation loop 11 or to a treatment zone 2 again. The at least one diverted partial flow 19 is preferably returned to the process liquid 4 of the same recirculation loop 11 from which it was removed, as also illustrated in FIG. 1. This is of advantage among other things because a temperature of the at least one partial flow 19 at least substantially corresponds to a temperature level of the process liquid 4 circulating in the recirculation loop 11.

[0104] In this manner, undesired substances can be continuously and/or constantly removed from the process liquid 4 during operation of the pasteurization plant 1. This firstly enables the process liquid 4 to be kept as clear and germ-free as possible for the ongoing operation of a pasteurization plant 1. In addition, the concentration of undesired ions such as metal cations, for example aluminum ions or aluminum compounds present in ionic form, can be kept as low as possible.

[0105] In addition, a pH value of the partial flow can be influenced by means of the at least one strongly acidic cation exchanger of the ion exchange device 24 with a view to obtaining a desired pH level during operation of the pasteurization plant 1 because the cations removed from the partial flow 19 are replaced by solvated H.sup.+ ions.

[0106] Other advantageous embodiments of the pasteurization plant 1 and embodiments of the method will be explained in more detail with reference to FIG. 2. The same reference numbers and component names are used in FIG. 2 for parts that are the same as those described with reference to FIG. 1 above. To avoid unnecessary repetition, reference may be made to the detailed description of FIG. 1 given above.

[0107] As illustrated in FIG. 2, a partial flow 19 of process liquid diverted from a recirculation loop 11 is firstly directed through a membrane filtration device 23. The membrane filtration device 23 of the cleaning device 16 may comprise several filter modules 26 and in FIG. 2, 4 filter modules 26 are illustrated by way of example. The number of filter modules 26 and also the filtration capacity of the filter modules 26 may be adapted respectively to the anticipated degree of soiling and/or to the volume of process liquid circulated during operation of the pasteurization plant 1. In principle, the filter modules 26 of the membrane filtration device 23 may be arranged in any configuration in the membrane filtration device 23, for example fluidically connected in series one after the other. In the embodiment illustrated in FIG. 2, the filter modules 26 are fluidically connected in parallel so that a partial quantity of the partial flow 19 can be circulated across or through a filter module 26 respectively.

[0108] The individual filter modules 26 may basically be of any design as long as they enable a tempered aqueous process liquid to be filtered. For example, a filter module 26 may have a plurality of hollow fiber membranes which may be mounted in a retentate chamber 27 on the intake side. These hollow fiber membranes may have pores with a pore diameter of between 0.01 m and 0.5 m for example, thus being suitable for micro- and/or ultra-filtration. The respectively open ends of the hollow fiber membranes of a filter module 26 may be embedded in a sealing means 28 in such a way that the open ends and the inner cavities of the hollow fibers open into a filtrate or permeate chamber 29 of a filter module 26. Accordingly, the sealing means 28 separate the retentate chamber 27 from the permeate chamber 29 in a sealed arrangement so that the at least one partial flow 19 of aqueous process liquid can only flow from the retentate chambers 27 by passing through the hollow fiber membrane walls from an external surface of the hollow fiber membranes into the interior of the hollow fibers and into the permeate chambers 29 of the filter modules 26. The at least one partial flow 19 is thus filtered and particulate and/or coagulated contaminants are held back on the retentate side.

[0109] As also illustrated in FIG. 2, the filter modules 26 of a membrane filtration device 23 can be respectively connected on the permeate or filtrate side to a back-flush liquid source 30 and on the retentate or intake side to a discharge 31 by pipes which can be shut off or opened as and when required sein. As a result, the filter modules 26 of the membrane filtration device 23 can be cleaned with a back-flushing liquid by reversing the flow direction through the filter modules 26 in order to clean the filter membranes, for example the hollow fiber membranes. For example, a filter cake can be removed from the retentate side of the filter membranes in this manner. In this respect, all of the filter modules 26 of a membrane filtration device 23 can be cleaned together, as also illustrated in FIG. 2. Alternatively, however, it may be that groups of filter modules or even every filter module 26 separately is connected to a back-flush liquid source 30 and a discharge 31 and can be selectively shut off or opened. Clean fresh water may be used as the back-flushing liquid, for example, to which cleaning chemicals may be added if necessary. In addition, the filter membranes may be flushed with a gas on the retentate side to assist the cleaning with back-flushing and to prevent a filter cake from building up.

[0110] As illustrated in FIG. 2, an ion exchange device 24 is fluidically connected downstream of the membrane filtration device 23 in the cleaning device 16. The ion exchange device 24 has at least one strongly acidic cation exchanger 32. In the embodiment illustrated as an example in FIG. 2, the ion exchange device 24 comprises two cation exchangers 32. As described above, a pH value of the partial flow 19 can be influenced by means of the cation exchanger(s) 32 during operation of the pasteurization plant 1 with a view to obtaining a desired pH level. A strongly acidic cation exchanger 32 may comprise an ion exchanger matrix and/or an ion exchanger resin having sulfonic acid groups as active groups, for example.

[0111] As also illustrated in FIG. 2, however, the ion exchange device 24 may comprise at least one strongly basic anion exchanger 33. As a result, undesired anions can also be removed from the at least one diverted partial flow 19 by means of the at least one strongly basic anion exchanger 33 during operation of the pasteurization plant 1. A strongly basic anion exchanger may comprise an ion exchanger matrix and/or an ion exchanger resin having quaternary ammonium groups as active groups, for example. A pH value of the at least one partial flow 19 can be influenced by means of the at least one strongly basic anion exchanger with a view to obtaining a desired pH level during operation of the pasteurization plant 1. The pH value of the at least one partial flow 19 can be influenced by regulating a quantity of process liquid flowing through the ion exchanger(s) 32, 33 and/or through the entire ion exchange device 24 for example, as will be explained in more detail.

[0112] In principle, in order to influence the pH value of the at least one partial flow 19 in a specific way, a ratio of an ion exchange total capacity of all the available strongly acidic cation exchangers 32 to an ion exchange total capacity of all the available, strongly basic anion exchangers 33 is selected depending on requirements with a view to obtaining a desired pH value of the at least one partial flow 19 or the process liquid. A pH value of the at least one partial flow 19 is preferably adjusted to a slightly acidic level. For example, it may be of advantage if an average pH value of the process liquid for treating the external surface of the containers is between 4 and 7 during operation of the pasteurization plant 1. This may be of advantage as a means of preventing the occurrence of so-called wet storage stain on aluminum materials on the treated containers, for example. Accordingly, the ion exchange total capacity of all the available strongly acidic cation exchangers 32 may be selected so that it is higher than the ion exchange total capacity of all the available strongly basic anion exchangers 33. Care must naturally be taken to ensure that the ion exchange total capacity is sufficient to efficiently remove undesired dissolved ions from the at least one partial flow 19.

[0113] Based on one advantageous way of implementing the method, it may be of advantage if a content of dissolved ions in the partial flow 19 upstream and downstream of the ion exchange device 24 is monitored respectively by sensors. To this end, a sensor means for monitoring a content of ions dissolved in the partial flow 19 may be fluidically connected upstream and downstream of the ion exchange device 24 respectively. Such sensor means might be provided in the form of conductivity sensors or other suitable measuring devices which enable information to be gleaned about the content of ions, for example.

[0114] As illustrated by way of example in FIG. 2, a pH value sensor 34 may be fluidically connected upstream and downstream of the ion exchange device 24 respectively. As a result, a content of ions dissolved in the at least one partial flow 19 can be monitored by measuring a pH value of the at least one partial flow 19 upstream and downstream respectively of the point at which ions are removed by means of the ion exchange device 24 during operation of the pasteurization plant 1.

[0115] By providing the pH sensors 34, a sudden increase in the concentration of ions dissolved in the partial flow 19 or in the process liquid generally can be detected, for example. For example, a sudden increase in the concentration of metal cations in the process liquid can be detected because these metal cations are exchanged by means of the at least one strongly acidic cation exchanger 32 with solvated H.sup.+ ions. This can in turn be detected by means of the pH value sensors 34 directly due to a sudden drop in the pH value of the at least one partial flow 19 after it has passed through the at least one cation exchanger 32 of the ion exchange device 24. Steps can then be taken if necessary to prevent further soiling of the process liquid by undesired dissolved ions. At best, by providing the pH value sensors 34, it is even possible to detect errors in the implementation of the pasteurization process and/or unplanned and undesired influences on the method, for example due to containers that are leaking or soiled with metal or aluminum dust. At the same time, providing such pH sensors 34 is of advantage in that they serve as a reference or measuring means for influencing the pH value of the at least one partial flow 19 with a view to obtaining a desired pH level.

[0116] A pH value of the at least one diverted partial flow 19 can be influenced by means of the ion exchange device 24 by regulating a quantity of process liquid flowing through the ion exchange device 24, for example. To this end, the at least one cleaning device 16 is assigned a flow regulating device 35 as a control means 21 for regulating and/or adjusting a specific volumetric flow of the at least one partial flow 19 for example, as illustrated in both FIG. 1 and FIG. 2. A flow regulating device 35 may be a flow regulating element 36 such as a flow regulating valve or an adjustable flap or other appropriate adjustable regulating elements. A flow regulating device 35 may also comprise a flow sensor means 37 for measuring a respective quantity of process liquid or a volumetric flow of the at least one diverted partial flow 19 flowing through the cleaning device 16. During operation of the pasteurization plant 1, the partial quantity of process liquid 4 diverted from the at least one recirculation loop 11 in order to create the at least one partial flow 19 can therefore be regulated by means of a flow regulating device 35. This in turn enables a pH value of the at least one partial flow 19 to be influenced because depending on the flow quantity and/or depending on a volumetric flow of the at least one partial flow 19, more or fewer dissolved ions are exchanged by means of the strongly acidic cation exchanger(s) 32 and if necessary the strongly basic anion exchanger(s) 33. As schematically indicated in FIG. 2, an additional conveying means 12, preferably a speed-regulated pump for example, may be used to regulate a quantity of process liquid flowing through the cleaning device 16.

[0117] In principle, an ion exchange device 24 may be connected to the at least one cleaning device 16 in such a way that the entire at least one partial flow 19 of process liquid 4 diverted or removed from a recirculation loop 11 can be circulated through the ion exchange device 24, as schematically illustrated in FIG. 1. However, it is also of practical advantage if the ion exchange device 24 is fluidically connected to the at least one cleaning device 16 via at least one flow regulating means 38 parallel with a flow line 39 for the partial flow 19, as is the case with the embodiment illustrated as an example in FIG. 2. As a result, during operation of the pasteurization plant 1, at least a part of the process liquid removed from the partial flow 19 can be directed by means of at least one flow regulating means 38, for example a flow regulating element 36, via the ion exchange device 24 and then returned to the partial flow 19 again. As a result, a quantity of process liquid flowing through the ion exchange device 24 can basically be regulated independently of other elements of the at least one cleaning device 16 and thus the quantity of dissolved ions exchanged per unit of time influenced. In particular, the pH value of the at least one partial flow 19 can also be influenced independently of other elements of the at least one cleaning device 16. As illustrated in FIG. 2, an additional conveying means 12, preferably a speed-regulated pump for example, may also be used to regulate a quantity of process liquid flowing through the ion exchange device 24.

[0118] Alternatively or in addition, it may also be of advantage if a flow regulating means 38 is provided for every ion exchanger 32, 33 of the ion exchange device 24. As a result, during operation of the pasteurization plant 1, a quantity of process liquid flowing through the ion exchanger(s) 32, 33 can be regulated separately by means of a flow regulating means 38 respectively provided for each ion exchanger 32, 33 of the ion exchange device 24, as may be seen in FIG. 2. In this manner, the removal of dissolved ions from the at least one partial flow 19 can be controlled and regulated even more accurately and the pH value of the at least one partial flow 19 can be influenced and adjusted even more precisely.

[0119] As also illustrated in FIG. 2, the ion exchange device 24 may be fluidically connected to at least one regeneration means 40, 41 for regenerating the ion exchanger(s) 32, 33. Naturally, a regeneration means 40 with regenerating liquid for the cation exchanger(s) 32 and a regeneration means 41 with regenerating liquid for the anion exchanger(s) 33 may be provided. During operation of the pasteurization plant 1, the ion exchangers 32, 33 can then be respectively regenerated depending on requirements. In particular, the at least one strongly acidic cation exchanger 32 may be regenerated depending on a change in pH value of the partial flow 19. Similarly, the at least one strongly basic anion exchanger 33 may be regenerated depending on a change in pH value of the partial flow 19. To this end, as described above, pH sensors 34 may be provided respectively upstream and downstream of the ion exchange device 24. Spent regenerating liquid can in turn be fed out via a discharge 31.

[0120] To further improve cleaning efficiency for the process liquid, the at least one cleaning device 16 may comprise another liquid treatment device 42 having metal particles or a metal mesh incorporating copper and/or zinc. This liquid treatment device 42 may be fluidically connected between the membrane filtration device 23 and ion exchange device 24 in the at least one cleaning device 16. The liquid treatment device 42 may also be disposed parallel with a flow line 39 for the partial flow 19 in the at least one cleaning device 16 so that it can be selectively fluidically shut off or opened, as illustrated in FIG. 2. During operation of the pasteurization plant 1, the at least one partial flow can then be additionally circulated through a liquid treatment device comprising metal particles or a metal mesh incorporating copper and/or zinc before the dissolved ions are removed.

[0121] By means of such a liquid treatment device 42, spontaneous oxidation and/or reduction reactions with some of the substances dissolved in the process liquid can be initiated during operation of the pasteurization plant 1. As a result, more noble metal cations than zinc and/or copper, for example heavy metal ions, iron ions, etc., can be removed from a diverted partial flow 19 for example. This is also of advantage for improving the efficiency of the downstream ion exchange device 24 because the ions removed by means of the liquid treatment device 42 no longer have to be removed from the at least one partial flow 19 by means of the ion exchange device 24 and therefore are not competing with other ions dissolved in the partial flow 19 during the ion exchange. The usable ion exchange capacity of the ion exchangers 32, 33 of the ion exchange device 24 is therefore advantageously available for drawing off or removing other undesired dissolved ions that cannot be removed by means of the liquid treatment device 42, for example aluminum ions and/or ions of aluminum compounds.

[0122] Furthermore, the at least one cleaning device 16 may comprise an adsorption device 43, which adsorption device 43 is fluidically connected downstream of the ion exchange device 24. The adsorption device 43 may have an activated carbon filter 44, for example. As a result, during operation of the pasteurization plant 1, after dissolved ions have been removed by means of the ion exchange device 24, dissolved substances may additionally be removed from the at least one partial flow 19 by means of an adsorption device 43, for example by means of an activated carbon filter 44.

[0123] In principle, it may be of practical advantage if the at least one cleaning device 16 is disposed in a recirculation loop 11 and/or is connected to a recirculation loop 11 by pipes, in which recirculation loop 11 process liquid 4 is circulated at a slightly lower temperature during operation of the pasteurization plant 1, as also illustrated in FIG. 1. As a result of this in particular, operation of the individual devices 23, 26, 42, 43 of the at least one cleaning device 16 is as gentle as possible. The process liquid 4 can nevertheless be efficiently cleaned on a continuous basis because the individual volumetric elements of the process liquid 4 are constantly mixed in the pasteurization plant 1 due to the circulation and/or forced circulation of the process liquid via the recirculation loop 11 or recirculation loops 11. In other words, in such situations, individual volumetric elements of the process liquid 4 are circulated via changing recirculation loops 11 and into and out of changing treatment zones 2 over time during ongoing operation. This also makes it possible to influence a pH value of the entire process liquid by exchanging the dissolved ions of the at least one partial flow 19 by means of the ion exchange device 24 of the at least one cleaning device 16.

[0124] FIG. 3, finally, illustrates parts of another example of an embodiment of a pasteurization plant 1 which may be of advantage in terms of continuously reusing and cleaning the process liquid 4. In FIG. 3, the same reference numbers and component names are used for parts that are the same as those described with reference to FIGS. 1 and 2 above. To avoid unnecessary repetition, reference may be made to the more detailed description of FIG. 1 and FIG. 2 above.

[0125] As may be seen from the parts of the embodiment of the pasteurization plant 1 illustrated as an example in FIG. 3, the pasteurization plant 1 comprises an air-cooled cooling tower 45 having a heat exchanger 46 through which the process liquid 4 can be circulated if necessary. In this manner, a partial volumetric flow of process liquid 4 can be circulated via a heat exchanger 46 of an air-cooled cooling tower 45 depending on requirements.

[0126] Air-cooled cooling towers are often needed in pasteurization plants for cooling a part of the process liquid 4, which cooled process liquid 4 can in turn be used to cool containers on completion of the pasteurization process, for example. Due to the fact that cooling towers usually need a high cooling capacity, a considerable amount of contaminants occur in conventional cooling towers without a heat exchanger. By providing the heat exchanger 46, contaminants can be efficiently prevented from getting into the process liquid 4 via or in the air-cooled cooling tower 45.

[0127] As illustrated in FIG. 3, in order to cool a partial quantity of process liquid 4 for example, a partial quantity of process liquid 4 is transferred from a recirculation loop 11 by means of conveying means 12 into a process liquid tank 47, for example a collection tank or similar, depending on requirements. Also depending on requirements, process liquid 4 can then be pumped out of the process liquid tank 47 though the heat exchanger 46 of the cooling tower 45 by means of another conveying means 12 and thus cooled by cooling air and then be returned to the process liquid tank 47 again. The cooled process liquid 4 from the process liquid tank 47 can then be returned to the recirculation loop 11 illustrated by way of example in FIG. 3.

[0128] The embodiments illustrated as examples represent possible variants, and it should be pointed out at this stage that the invention is not specifically limited to the variants specifically illustrated, and instead the individual variants may be used in different combinations with one another and these possible variations lie within the reach of the person skilled in this technical field given the disclosed technical teaching.

[0129] The protective scope is defined by the claims. The description and drawings may be used to interpret the claims. Individual features or combinations of features from the different embodiments illustrated and described may be construed as independent inventive solutions or solutions proposed by the invention in their own right. The objective underlying the independent inventive solutions may be found in the description.

[0130] All the figures relating to ranges of values in the description should be construed as meaning that they include any and all part-ranges, in which case, for example, the range of 1 to 10 should be understood as including all part-ranges starting from the lower limit of 1 to the upper limit of 10, i.e. all part-ranges starting with a lower limit of 1 or more and ending with an upper limit of 10 or less, e.g. 1 to 1.7, or 3.2 to 8.1 or 5.5 to 10.

[0131] For the sake of good order, finally, it should be pointed out that, in order to provide a clearer understanding of structure, constituent parts are illustrated to a certain extent out of scale and/or on an enlarged scale and/or on a reduced scale.

TABLE-US-00001 List of reference numbers 1 Pasteurization plant 2 Treatment zone 3 Delivery means 4 Process liquid 5 External surface 6 Container 7 Conveyor device 8 Conveyor belt 9 Conveying direction 10 Floor region 11 Recirculation loop 12 Conveying means 13 Means 14 Means 15 Heating device 16 Cleaning device 17 Removal means 18 Returning means 19 Partial flow 20 T-piece 21 Control means 22 Shut-off means 23 Membrane filtration device 24 Ion exchange device 25 Conveying means 26 Filter module 27 Retentate chamber 28 Sealing means 29 Permeate chamber 30 Back-flush liquid source 31 Discharge 32 Cation exchanger 33 Anion exchanger 34 pH value sensor 35 Flow regulating device 36 Flow regulating element 37 Flow sensor means 38 Flow regulating means 39 Flow line 40 Regeneration means 41 Regeneration means 42 Liquid treatment device 43 Adsorption device 44 Activated carbon filter 45 Cooling tower 46 Heat exchanger 47 Process liquid tank