HK1256962B - Pasteurization plant and method for operating a pasteurization plant - Google Patents

Description

Pasteurization installation and method for operating a pasteurization installation

Technical Field

The invention relates to a method for operating a pasteurization installation and a pasteurization installation.

Background

Pasteurization devices are used to allow long-term storage of food products by targeted tempering of the food products. The food product is typically heated to a higher temperature level and maintained at this higher temperature level for a certain duration of time in order to kill the surviving microorganisms. In many cases, a treatment process is practical in which the food is filled into a container and the container is closed before pasteurization and a tempered or heated treatment liquid is applied to the outside of the container for tempering or pasteurization of the food. In this way, products that are ready for storage or sale can be provided.

So-called tunnel pasteurizers are generally used, in which the containers filled with food and closed are guided through one or more treatment zones and are sprinkled or sprayed with a tempered treatment liquid in the respective treatment zone. Aqueous treatment liquids are generally used, which are at least partially guided in a circulation around the treatment zone for reuse. This serves on the one hand to reduce the amount of fresh treatment liquid or fresh water that has to be supplied. On the other hand, the energy consumption required for tempering the treatment liquid can also be reduced in this way.

When the aqueous treatment liquid is continuously reused in this way or when the treatment liquid is continuously recirculated, it is unavoidable that impurities enter the aqueous treatment liquid over time. The source of such impurities may be, for example, ambient air, a cooling tower for cooling the treatment liquid as required, an operator, or, for example, a container or the contents of a container. For example, during the manufacture of the container, impurities, for example due to machining steps or the like, may remain on the outside of the container. It may also happen that, due to the slightly unsealed container, the food components enter the treatment liquid during the operation of the pasteurization device. Here, the leaktightness usually occurs in the region of the closure of the container, for example at a screw closure of a beverage bottle or at the closure of a beverage can. Furthermore, it may happen that the container is damaged or even broken during or before the handling.

In the past, measures have been proposed for the continuous purification of the reused treatment liquid of a pasteurization installation. Measures for purification are proposed primarily with the aim of removing filterable and/or depositable particles. These measures are mainly related to the filtration of large particles, or the separation of large particles by sedimentation by gravity, as described for example in EP 2722089 a 1. Furthermore, measures are proposed by means of which even fine to very fine particles, including microorganisms, can be removed from the treatment liquid guided in the circuit. Good results can be achieved in this respect, for example, by means of the measures proposed in WO 2016/100996 a1 based on the applicant.

However, there is also a need to develop an improved method for purifying aqueous treatment liquids in a pasteurization installation, in particular to enable the most ecologically and economically viable continuous purification of continuously reused treatment liquids. In addition, there is a need for improvements in particular with regard to the targeted control as possible and thus resource-saving and economical purification of the tempered treatment liquid guided in a circuit for reuse in a pasteurization installation.

Disclosure of Invention

It is an object of the present invention to provide an improved method for operating a pasteurization installation, which method allows for as efficient and continuous a purification of an aqueous treatment liquid as possible. This object is achieved by the method and the pasteurization installation according to the invention.

Said object is achieved by the method and the pasteurization device according to the invention.

The method according to the invention comprises the following steps: the closed container filled with the food product is transported through one or more treatment zones. Treating the containers with the tempered, aqueous treatment liquid in the one or more treatment zones by applying the treatment liquid onto the outside of the containers. At least a part, preferably at least a major part, of the treatment liquid from the treatment zone is returned to the treatment zone in at least one circulation circuit by means of a conveying device for reuse. At least one partial quantity of the volume flow of the treatment liquid guided through the at least one circulation circuit is extracted or branched off from the at least one circulation circuit per unit time to form at least one partial flow, which is guided through a purification device, which is connected to the at least one circulation circuit in terms of flow technology and comprises a membrane filtration device with one or more filtration modules, and is filtered by the purification device.

It is provided here that the flow or volume flow of the at least one partial flow through the membrane filtration device or the purification device is continuously monitored by means of a sensor device. It is furthermore provided that, on the basis of the monitoring, the partial quantity of the treatment liquid withdrawn per unit time from the at least one circulation circuit is influenced in terms of the desired flow rate of the at least one partial flow through the membrane filtration device by adjusting the flow rate adjustment position of the at least one adjustable flow rate adjustment means relative to the membrane filtration device. After passing through the purification device, the at least one partial stream is returned to the circulation circuit or to a treatment zone.

By the measures given, a method can be provided by which coagulated impurities, such as, for example, turbidity, dust particles, food constituents, parts of containers, precipitation products, slime formers, algae or microorganisms, can be continuously removed from the treatment liquid in an efficient manner. In particular, it can be ensured by monitoring and influencing the flow rate through the membrane filtration device that a sufficiently large flow rate of the at least one partial flow through the membrane filtration device or the purification device can be set or controlled continuously for the desired removal of impurities.

Furthermore, it is advantageous that the time-dependent contamination level of the treatment liquid can be identified and compensated for. A higher degree of contamination of the process liquid, for example in the case of a constant flow rate control position of the at least one flow rate control member relative to the membrane filtration device, has the effect that the flow rate of the at least one partial flow through the membrane filtration device is reduced. The flow rate of the at least one partial flow through the membrane filtration device and thus the filtration efficiency can then be increased by increasing the flow rate control position of the at least one flow rate control element relative to the membrane filtration device. The flow adjustment position of the at least one flow adjustment mechanism relative to the membrane filtration device can be reduced at lower levels of contamination in the process liquid. The flow rate or volume flow of the at least one partial flow can thereby be adjusted to the respectively necessary level in an efficient manner and form.

In general, the measures specified advantageously provide an effective, purpose-controlled, continuous purification of the treatment liquid conducted in the circulation circuit or circuits. After passing through the purification device, the at least one partial stream is preferably fed back into the same circulation circuit from which the partial stream was branched off. This achieves the advantage that the temperature level of the at least one partial stream corresponds at least substantially to the temperature level of the treatment liquid conducted in the circulation circuit. Possible additional temperature regulation of the process liquid volume supplied to a process zone can therefore be dispensed with.

In the case of such a purification of the partial flow or partial flows of the treatment liquid, it is advantageous in the pasteurization device to constantly mix the individual volume elements of the treatment liquid as a result of the flow or forced transport of the treatment liquid via the one or via the individual circulation circuits. Such mixing is particularly effective, for example, in a pasteurization installation in which a volumetric flow of the treatment liquid is removed from the treatment zones and fed back to the other treatment zones in each case via a circulation circuit. In other words, in this case, the individual volume elements of the treatment liquid are guided over time through the transformed circulation circuit or are supplied to and removed from the transformed treatment zone in a continuous operation. Thus, only one partial quantity of the treatment liquid is continuously purified in each case by forming the partial flow, whereby undesired impurities can be removed from the entire treatment liquid effectively over time.

In a development of the method, it can be provided that the desired flow rate of the at least one partial flow through the membrane filtration device is selected from a range of between 0.1% and 50% relative to the volume flow of the treatment liquid in the at least one circulation circuit before the partial flow is extracted.

By selecting the flow rate from the specified range, the treatment fluid or the at least one partial flow of the treatment fluid can be purified in an efficient manner, adapted to the degree of contamination of the treatment fluid, accordingly. It is advantageous here that all the treatment liquid circulating in the pasteurization device can be effectively purified by continuously withdrawing and filtering a smaller partial quantity of the treatment liquid from the at least one circulation circuit. The desired flow rate of the at least one partial stream through the membrane filtration device is preferably selected from the range between 0.5% and 20% relative to the volume flow of the treatment liquid in the at least one circulation loop before the partial stream is extracted. Of course, the total filtration capacity of the membrane filtration device or the number of filtration modules of the membrane filtration device and the respective filtration capacity can be adapted or selected accordingly in order to effectively purify the at least one partial stream.

In a preferred embodiment of the method, it can be provided that the partial quantity of process liquid withdrawn per unit time from the at least one circulation circuit is influenced in terms of the desired flow rate of the at least one partial flow through the membrane filtration device by adjusting the degree of opening of the at least one flow rate regulating means relative to the membrane filtration device.

Adjusting the degree of opening of the flow rate control device formed for this purpose has the advantage that the influencing of the flow rate of the at least one partial flow through the membrane filtration device can be carried out with comparatively simple means, but still efficiently and precisely. Furthermore, it is advantageous that no additional conveying means, for example an additional pump, may be required here, or that conveying means for conveying a volume flow of the treatment liquid through the circulation circuit may also be used for conducting the at least one partial flow through the at least one purification device or the membrane filtration device. Examples of the flow rate adjusting mechanism capable of adjusting the degree of opening of the membrane filtration device include an adjusting valve, a poppet valve, and a three-way distribution valve. In these cases, the flow rate can also be increased by increasing the degree of opening, that is, by adjusting the degree of opening of the flow rate adjusting mechanism in a direction in which the degree of opening is greater with respect to the degree of opening of the membrane filtration device. Or the flow through the membrane filtration device may be reduced by reducing the degree of opening relative to the membrane filtration device.

In one embodiment of the method, the flow control position or the open position of the at least one adjustable flow control means relative to the membrane filtration device is monitored continuously, which is also advantageous.

The flow control position or opening or open position of the at least one flow control element can thus be used as a monitoring or control means, for example for detecting a continuously forming cover layer on the membranes of the filter modules of a membrane filtration device.

In this case, it can further be provided that, when a limit value is exceeded in the flow control position or the open position of the at least one flow control element, a measure is taken or initiated.

By taking measures when a limit value of the flow rate regulating position or the opening position is exceeded, an excessive reduction in the filtration efficiency can be prevented in time, for example, during operation of the pasteurization device. The limit values for the flow rate setting position or the opening position can in principle be determined or predefined freely here. For example, it is possible to select or determine the maximum possible opening degree or the maximum possible opening position of the at least one flow rate regulating element as the limit value.

However, it can also be provided that measures are taken below a limit value for the monitored flow rate of the extracted at least one partial flow through the membrane filtration device.

This also makes it possible, for example, to prevent an excessive reduction in the filtration efficiency during operation of the pasteurization device. The limit value of the detected flow rate or the detected volume of the at least one partial flow can in principle also be freely predetermined.

As a measure, it can be provided, for example, that a backwashing is carried out with reversal of the flow direction of one or more or all of the filter modules of the membrane filtration system.

During the continuous filtration of the at least one partial stream, the substances removed or filtered out of the at least one partial stream can be concentrated on the retentate side of the filtration module of the membrane filtration device. Thus, on the retentate side, deposits may form over time on the membranes of the or each filtration module, which deposits may gradually make it difficult for the process liquid to flow through the membranes. Such deposits can be effectively removed from the filtration membrane by counter-current flushing of the or each filtration module. This advantageously also allows a significant improvement in the flow passage of the at least one partial flow through the filter membrane, so that a sufficiently large flow rate of the at least one partial flow is achieved even with a small flow rate adjustment position or a small opening of the at least one flow rate adjustment means relative to the membrane filtration device. Alternatively, the counter-current flushing of the or each filter module of the membrane filtration device can also be carried out at predeterminable times or at defined time intervals. In principle, all filter modules of a membrane filtration system can be flushed in countercurrent at the same time.

In a further development of the method, it can be provided that the flow rate of the extracted partial stream is continuously monitored by means of a sensor device comprising a flow rate sensor.

In this way, an effective sensor device can be used, with which the volume flow or the flow rate through the membrane filtration device can be directly detected or monitored.

However, it is also possible to monitor the pressure loss at the membrane filtration device continuously by means of a sensor device comprising a differential pressure sensor or at least two pressure sensors.

This makes it possible to monitor the permeability of the membrane filtration device using relatively economical sensor means. The flow through the membrane filtration device can also be derived. This is in particular done in conjunction with a corresponding flow regulating position or open position of the at least one flow regulating means relative to the membrane filtration device.

In a further embodiment of the method, however, it can also be provided that the flow rate of the treatment liquid through the filter modules or filter module groups of the membrane filter device is continuously monitored by means of a sensor device. Wherein the flow through the individual filter modules or groups of filter modules is summed to the total flow through the membrane filtration device.

In this way, for example, the state of individual filter modules or groups of filter modules, for example, the permeability or the clogging due to deposit formation, can be monitored independently of one another. The throughflow rates through the individual filter modules or filter module groups are added to one another here to form the total throughflow rate through the membrane filtration device.

It is further possible to provide that, below a respectively defined limit value for the flow rate through the individual filter modules or filter module groups, the respective individual filter modules or the respective filter module groups are flushed back with reversal of the flow direction.

In this case, it is advantageous if the individual filter modules or groups of filter modules can be backflushed independently of one another, so that filter modules which are not backflushed can continue to operate in the filter mode of operation. Furthermore, it is possible by this measure to specifically and individually eliminate filter membrane blockages occurring as a result of deposit formation for individual filter modules or groups of filter modules. In this way, it is also possible to avoid backwashing of filter modules that do not require backwashing at the time of the backwashing operation.

In principle, it is also possible to set the respective flow rates of the treatment liquid through the individual filter modules or filter module groups to be influenced by individual flow rate control means. In this way, the respective flow rate through a filter module or a group of filter modules can be influenced independently of the other filter modules of the membrane filter device. The respective throughflows through the individual filtration modules are here summed up to the total throughflow of the at least one partial flow extracted from the at least one circulation circuit through the membrane filtration device.

However, it may also be expedient to apply a gas flow to the filtration modules of the membrane filtration device periodically or as required on the retentate side.

Such loading with a gas stream on the retentate side is advantageous for loosening particles from the filtration membranes of the or each said filtration module. Here, the retentate-side deposits on the filter membrane wall can be broken up by the introduction of gas bubbles and thus prevent the formation of a cover layer which technically leads to clogging or clogging of the pores of the filter membrane. Additionally, the filter membrane can be put into motion by the gas flow, in which case deformation and oscillation of the filter membrane contribute to the loosening of the deposit. This can also be achieved, for example, by friction forces between the individual filter membranes.

In particular, it can be provided that during the backflush process a gas flow is applied to the filtration module of the filtration device on the retentate side.

As a result, the backwashing process for removing deposits from the filter membranes of the or each filter module can be assisted particularly effectively, and therefore can be carried out significantly more effectively.

In a preferred development of the method, it can be provided that the flow rate of the at least one partial flow through the membrane filtration device and/or the flow rate regulation position or the open position of the at least one flow rate regulation means is recorded over a period of time.

By recording or registering the flow and/or the flow regulating position or the opening position at least over a determined period of time, the change in state of the at least one purification device or membrane filtration device and/or the process liquid can be monitored. In particular, in this way, it is possible in principle to detect a state deviating from the normal course of the method on the basis of an atypical, temporal change in the recorded flow and/or the method of adjusting the position or the opening position of the flow. For example, it is thereby possible to detect an abnormal introduction of impurities into the treatment liquid, for example as a result of a faulty or unsealed filling of the container. On the other hand, errors or damage, for example damaged or leaking filter modules, or filter modules which are blocked by objects, can also be detected on the purification device itself. In principle, it is also possible to identify temperature levels of the at least one partial flow that differ significantly from the desired temperature, since the permeability of the treatment liquid through the filter membrane increases with increasing temperature of the treatment liquid and decreases with decreasing temperature of the treatment liquid. In this case, such an undesired deviation from normal operation can in principle be detected by an atypical change in the monitored flow or in the monitored flow control position or opening position in comparison with normal operation by a larger or faster method.

In this case, provision can furthermore be made for measures to be taken when an atypical change in the method of the monitored flow of the at least one partial flow is detected or when an atypical change in the method of the flow control position or the open position of the at least one flow control element is detected.

For example, provision can be made for at least one chemical from the group comprising pH regulators, softeners, corrosion inhibitors, surfactants and antimicrobial actives to be incorporated into the treatment liquid as a measure.

In principle, the chemical content in the treatment liquid may lead to undesirable effects at all. For example, an inappropriate pH for the treatment liquid may lead to undesirable flocculation of other components or to undesirable interactions with the container. Corrosive components can generally cause the device itself, for example a pasteurization device, to loosen. Furthermore, hardeners may, for example, lead to coagulation or the formation of undesirable particles. In addition, the corresponding growth rate or proliferation rate of microorganisms, for example bacterial colonies or algae, is to be taken into account, which may become very pronounced, for example, on account of dissolved nutrients in the treatment liquid. This situation may be even further exacerbated by other parameters of the treatment liquid, such as, for example, elevated temperature levels. After detection of a process-atypical situation, for example a strong reduction in the flow through the membrane filtration device, this undesirable effect can be eliminated by the incorporation or addition of chemicals as a result of the targeted addition of chemicals.

In addition, it can be provided that the purification device or the pasteurization device is serviced as a measure.

In this way, it is possible to repair a detected process error or damage to the pasteurization installation, in particular to a damaged purification device, for example a damaged filter module, as a result of the detection of a process-atypical state.

In a variant of the method, it may be expedient to heat the food in the container in one treatment zone or to heat the food in the container gradually in a plurality of treatment zones, to subsequently pasteurize the food in the container in one treatment zone or in a plurality of treatment zones and to thereafter cool the food in the container in one treatment zone or to cool the food gradually in a plurality of treatment zones.

In this way, a particularly protected pasteurization of the food can be provided, since large temperature jumps can be avoided by the tempered treatment liquid. In addition, in this way a uniform tempering of the food can be provided in the respective container.

In this case, it can be provided in particular that the at least one partial stream is taken from a circulation circuit in which the treatment liquid stream has a temperature level of between 30 and 55 ℃.

Particularly good filtration results can be achieved on the one hand when the temperature of the treatment liquid lies within the specified range, since a good passage of the treatment liquid through the or each filter module can be provided. On the other hand, damage to the filter membrane, in particular to the plastic film, can thus be effectively prevented. The at least one partial stream is preferably taken from a circulation loop in which the treatment liquid stream has a temperature level between 20 and 60 ℃.

Finally, embodiments of the method in which a partial volume flow of the process liquid is conducted through the heat exchanger of the cooling device as required can also be advantageous.

The efficiency of the purification of the treatment liquid can be further increased by this measure. This is because, firstly, it is possible to prevent impurities from entering the treatment liquid through or in the cooling device. The cooling device is usually required for cooling a part of the treatment liquid, which cooled treatment liquid can be used for cooling the container after pasteurization. Here, since in most cases a large cooling capacity is required, for example for a conventional air-cooled cooling tower without a heat exchanger, very large amounts of impurities can enter at all.

The pasteurization apparatus according to the invention comprises: one or more treatment zones having a supply means for applying a tempered treatment liquid onto the outside of a closed container filled with a food product; a conveying means for conveying the containers through the treatment zone; at least one circulation circuit, wherein at least a part of the treatment liquid from the treatment zone can be returned to the treatment zone in the at least one circulation circuit by means of a conveying device for reuse; and a purification device which is connected in flow-technical fashion to the at least one circulation circuit and which comprises a membrane filtration device having one or more filtration modules, through which purification device at least one partial flow can be conducted and which can be filtered, characterized in that a sensor device is provided, by means of which the flow rate of the at least one partial flow through the membrane filtration device can be continuously monitored, and at least one adjustable flow rate control means is provided, on the basis of which the partial quantity of the treatment liquid extracted per unit time from the at least one circulation circuit can be influenced in terms of the desired flow rate of the at least one partial flow through the membrane filtration device by adjusting the flow rate control position of the at least one adjustable flow rate control means relative to the membrane filtration device, wherein the at least one partial flow can be reintroduced back into the circulation circuit or into the treatment region after passing through the purification device In (1).

Drawings

For a better understanding of the invention, it is explained in detail with the aid of the following figures.

In each case in a clearly simplified schematic representation:

FIG. 1 shows a schematic view of an embodiment of a pasteurization apparatus;

FIG. 2 shows a schematic view of an embodiment of a purification device of a pasteurization installation;

fig. 3 shows a schematic view of a further embodiment of a pasteurization device in part.

Detailed Description

It is first pointed out that in the differently described embodiments identical parts are provided with the same reference numerals or the same component names, wherein the disclosure contained in the entire description can be reasonably transferred to identical parts having the same reference numerals or the same component names. The positional references selected in the description, such as upper, lower, lateral, etc., also relate to the currently described and illustrated figures and can also be transferred to new positions in the event of a change in position.

Fig. 1 schematically shows an embodiment of a pasteurization device 1. The pasteurization installation 1 comprises one or more treatment zones 2 with a supply device 3 for applying a treatment liquid 4 onto the outer side 5 of a container 6. In the exemplary embodiment according to fig. 1, 5 treatment zones 2 are shown by way of example, wherein it is per se understood that more or fewer treatment zones 2 can also be provided according to the specific requirements and design of the pasteurization device 1.

In operation of the pasteurization device 1, the pasteurization of the food product is carried out in that the container 6 is filled with the food product beforehand and the container 6 is closed. The treatment of the containers 6 filled with food and closed is carried out in the respective treatment zones 2 by applying an aqueous treatment liquid 4 onto the outside of the containers 6 by means of said supply means 3. The supply means 3 of the respective treatment zone 2 can be formed, for example, by spray heads or nozzle-type spraying means or, in general, by means for distributing the treatment liquid in the respective treatment zone 2. In this way, the tempered aqueous treatment liquid 4 is applied to the outside 5 of the container 6, as a result of which the container 6 and thus the food filled into the container 6 can be tempered and pasteurized in a targeted manner. The container may consist of a bottle, a can or another reservoir, for example, and may in principle be made of various different materials, and may be coated or printed.

A conveying device 7 is provided for conveying the containers 6 through the treatment zone 2. In the embodiment shown in fig. 1, the conveying device 7 comprises two driven conveyor belts 8, by means of which the containers 6 filled with food and closed are conveyed in two layers through the treatment zone 2 in operation of the pasteurization device 1. This can take place, for example, from left to right in the transport direction 9 indicated by an arrow in fig. 1.

In the operation of the pasteurization device 1, it can be provided, for example, that the food in the containers 6 is first heated in one treatment zone 2 or in a plurality of treatment zones 2. In the exemplary embodiment shown in fig. 1, the food or containers 6 can be heated gradually, for example, in two treatment zones 2 shown on the left. After heating, the food products can be pasteurized in the treatment zone 2 or in a plurality of treatment zones 2, for example by supplying a pasteurized, conditioned treatment liquid 4 into the treatment zone 2 shown in the middle of fig. 1. After this, the food or containers 6 can be cooled again in the treatment zone 2 or in a plurality of treatment zones 2. The gradual cooling by supplying the treatment liquid 4 with a temperature which is suitable for cooling the container 6 can be carried out, for example, in two treatment zones 2 shown on the right in fig. 1.

That is to say, it can be provided, for example, that the food is heated in the treatment zone 2 which is arranged first in the conveying direction 9 and that the food is further heated in the treatment zone 2 which is arranged subsequently in the conveying direction 9. In the treatment zones 2 arranged subsequently in the conveying direction 9, the food can then be pasteurized by applying a treatment liquid 4 having a particularly high temperature level, for example between 50 ℃ and 110 ℃, onto the outer side 5 of the container 6. In the two treatment zones 2 arranged downstream in the conveying direction 9, the food or the containers 6 can be cooled in a targeted manner by means of the correspondingly tempered, relatively cold treatment liquid 4. This is advantageous, mainly because it is thereby possible to pasteurize the food as protected as possible, in particular because the food is not damaged by the tempering itself.

After the application of the tempered treatment liquid 4 to the outer sides 5 of the containers 6 in the treatment zones 2, the treatment liquid can be collected in the lower bottom region 10 of the respective treatment zone 2 and can be conducted out of the respective treatment zone 2 again. In order to discharge the treatment liquid 4 from the treatment region 2 and to return at least a part of the discharged treatment liquid 4 to one of the treatment regions 2 or one of the treatment regions 2, the pasteurization device 1 comprises at least one recirculation circuit 11. In operation of the pasteurization device 1, at least a part of the treatment liquid 4, preferably a majority of the treatment liquid 4 or the entire treatment liquid 4, is then returned from the treatment zone 2 for reuse in the at least one circulation circuit 11 by means of the conveying means 12 into a treatment zone 2.

As can be seen with the aid of the exemplary embodiment shown in fig. 1, it can be provided, for example, that the treatment liquid 4 is withdrawn from one treatment zone 2 via a circulation circuit 11 and is supplied to the other treatment zone 2. In the embodiment shown, the treatment liquid 4 can be supplied, for example, from the treatment zone 2 shown on the far left to the treatment zone 2 shown on the far right via a circulation circuit 11. Conversely, the treatment liquid 4 can be supplied, for example, from the treatment zone 2 shown on the far right to the treatment zone 2 shown on the far left for heating the containers 6 or the food products via a circulation circuit 11. This may be expedient, mainly because the treatment liquid 4 is cooled or heated during application or application to the container 6, respectively. By means of said cooling or heating, the treatment liquid 4 from the respective one treatment zone 2 can now have a temperature level which is favorable for the other treatment zone 2. On the other hand, however, it may be expedient for the treatment liquid 4 from a treatment zone 2 to be returned via a circulation circuit 11 into the same treatment zone 2, as is shown with respect to the treatment zone 2 shown in the middle in fig. 1, which is provided for pasteurizing the food products.

In order to convey or to conduct a corresponding volume flow of the treatment liquid 4 in the one or more circulation circuits 11, a conveying device 12, for example a pump, can be provided in each case, as is shown in fig. 1. It is also possible for the pasteurization device 1 to have a device 13 for removing a portion of the treatment liquid 4 from the circulation circuit 11, for example for taking samples. It is also possible to provide that the pasteurization device 1 comprises means 14 for supplying substances, for example fresh treatment liquid 4, for example fresh water or chemicals, etc. Such means 13, 14 can be formed, for example, by lines which are provided for supplying and discharging the treatment liquid 4 into and out of a collector or the like, or the means 13, 14 can be flow-technically connected in line for the purpose of tempering the treatment liquid with a heating and/or cooling device. Fig. 1 shows, by way of example, a heating device 15, for example a steam heater or a heat pump, which heating device 15 is fluidically connected via means 13, 14 to the circulation circuit 11 for returning the treatment liquid 4 into the treatment zone 2 shown in the middle. In this way, the treatment liquid for the circulation circuit 11 can be heated to a temperature level which is correspondingly required for the pasteurization of the food product.

In operation of the pasteurization device 1, impurities or undesired substances can enter the aqueous treatment liquid over time as a result of the continuous introduction of the treatment liquid 4 through the circulation circuit 11 or the continuous reuse of the treatment liquid 4. In the method for operating the pasteurization installation 1, it is therefore provided that at least one partial quantity of the volume flow of the treatment liquid 4 conducted through the at least one circulation circuit 11 is withdrawn or branched off per unit time to form at least one partial flow 16, and that the at least one partial flow 16 is conducted through a purification device 17 fluidically connected to the at least one circulation circuit 11 and filtered through the purification device, which, as shown in fig. 1, comprises a membrane filter device 18 having one or more filter modules.

In the exemplary embodiment shown in fig. 1, two purification devices 17 are shown by way of example, each comprising a membrane filtration device 18, which purification devices 17 are each fluidically connected to a different recirculation loop 11. It is of course also possible to provide only one purification device 17, or a pasteurization device 1 can also comprise more than two purification devices 17. The number of purification devices 17 and the filtration capacity of the respective membrane filtration device 18 can here also be selected or determined, respectively, taking into account the specifications or the processing capacity of the respective pasteurization installation 1. Furthermore, it is also possible to provide that a plurality of purification devices 17 are fluidically connected to one circulation circuit 11 or one of the circulation circuits 11.

By continuously extracting and filtering the at least one partial stream 16, the treatment liquid 4 of the pasteurization device 1 can be purified overall or all of the treatment liquid 4 can be purified. It is advantageous here that, during the method for operating the pasteurization device 1, a continuous mixing of the volume elements of the treatment liquid 4 is achieved as a result of the flow or forced conveyance of the treatment liquid via the circulation circuit 11. In other words, in this case, the individual volume elements of the treatment liquid 4 are supplied to the transformed treatment zone 2 or are removed from the transformed treatment zone 2 via the transformed circulation circuit 11 over time in continuous operation, so that, over time, eventually all of the treatment liquid 4 is filtered by means of the membrane filtration device 18.

In order to improve the filtration efficiency or to control the purification of the at least one partial stream 16 and to monitor the method, it is provided that the flow rate or the volume flow of the at least one partial stream 16 through the membrane filtration device 18 is continuously monitored by means of a sensor device 19. It is also provided that, on the basis of the monitoring, the partial quantity of the treatment liquid 4 withdrawn per unit time from the at least one recirculation circuit 11 is influenced in respect of the desired flow rate of the at least one partial stream 16 through the membrane filtration device 18 by adjusting the flow rate setting position of the at least one adjustable flow rate setting means 20 relative to the membrane filtration device 18. The at least one partial stream 16 is returned to a circulation circuit 11 or a treatment zone 2 after passing through a purification device 17 or a membrane filtration device 18, as is shown in fig. 1.

The at least one branched partial stream 16 is preferably supplied in turn to the treatment liquid 4 of the same circulation circuit 11 from which it has been extracted. This is also advantageous because the temperature level of the at least one partial stream 16 is at least approximately equal to the temperature level of the treatment liquid 4 conducted in the circulation circuit 11.

The flow control means 20 for the two membrane filtration devices 18 and/or the purification device 17 are only shown very schematically in fig. 1 for the sake of illustration. The flow rate control device 20 can be formed, for example, by a pump 21 with an adjustable number of revolutions, shown by dashed lines in fig. 1, or a similar adjustable delivery device. In this case, the flow rate of the at least one partial stream 16 through the membrane filtration device 18 can be adjusted as a flow rate control position relative to the membrane filtration device 18, i.e. the number of revolutions of the pump 21 can be adjusted by increasing or decreasing.

The method is preferably carried out in such a way that the partial quantity of the treatment liquid 4 extracted per unit time from the at least one circulation circuit 11 is influenced in respect of the desired flow rate of the at least one partial stream 16 through the membrane filtration device 18 by adjusting the degree of opening of the at least one flow rate adjustment means 20 relative to the membrane filtration device 18. Examples of the flow rate adjusting mechanism that can be adjusted in the degree of opening with respect to the membrane filtration device 18 include an adjusting valve, a poppet valve, and a three-way distribution valve. By means of such a flow rate control device 20, the degree of opening or the open position relative to the membrane filtration device 18 and thus the flow rate or the volume flow of the at least one partial flow 16 through the at least one purification device 17 or the membrane filtration device 18, respectively, can be increased or decreased as required. In this way the filtration efficiency can be further increased or decreased accordingly. The open position of such a flow regulating means 20 can be adjusted, for example, between a maximum open position relative to the membrane filtration device 18 and a completely closed open position relative to the membrane filtration device 18.

In order to control the withdrawal of the at least one partial quantity of treatment liquid 4 from the at least one circulation circuit 11 or in order to control the flow rate of the at least one partial stream 16 through the membrane filtration device 18, it is naturally also possible in principle to use or adjust a plurality of flow rate adjustment means 20 in combination with one another.

The desired flow rate of the at least one partial stream 16 through the membrane filtration device 18 is preferably selected from the range between 0.1% and 50% with respect to the volume flow of the treatment liquid 4 in the at least one circulation loop 11 before the extraction of the partial stream 16. The flow rate of the at least one partial stream 11 is selected from the range between 0.5% and 20% with respect to the volumetric flow of the treatment liquid 4 in the at least one circulation loop 11 before the extraction of the partial stream 16.

It may furthermore be expedient to extract the at least one partial stream 16 from the circulation loop 11 of the treatment liquid 4 stream having a temperature level of between 20 ℃ and 60 ℃. Particularly good filtration results can be achieved on the one hand when the temperature of the treatment liquid 4 lies within the specified range, since good passability of the treatment liquid 4 through the filter membranes of the filter modules of the membrane filtration device 18 can be provided. On the other hand, damage to the filter membrane, in particular to the plastic film, can thus be effectively prevented. The at least one partial stream 16 is extracted from the circulation loop 11 of the flow of treatment liquid 4 having a temperature level between 30 ℃ and 55 ℃.

The respective flow rate or the respective volume flow of the at least one partial stream 16 through the membrane filtration device 18 can be monitored, for example, by means of a sensor device 19 comprising a flow rate sensor 22, as is also shown in fig. 1. However, it is also possible to monitor the pressure loss at the membrane filtration device 18 continuously by means of a sensor device 19 comprising a differential pressure sensor 23 or at least two pressure sensors, as is also shown in fig. 1. In the latter case, the flow of the at least one partial stream 16 through the membrane filtration device 18 can be estimated in conjunction with the respective flow adjustment position or open position of the at least one flow adjustment means 20 relative to the membrane filtration device 18.

However, it may also be expedient independently to continuously monitor the flow control or opening position of the at least one adjustable flow control element 20 relative to the membrane filtration device 18. This is advantageous, mainly because a means for controlling or monitoring the state, for example the state of contamination of the process liquid 4 and/or the purification device 17 or the membrane filtration device 18, can thereby be provided.

In this case, for example, it can be provided that the limit values for the control technology are selected or determined for the flow rate of the at least one partial flow 16 through the membrane filtration device 18, which is monitored by the sensor, and/or for the monitored flow rate control or open position of the at least one flow rate control element 20.

In this case, it can be further provided, for example, that measures are taken or initiated when a limit value of the flow rate control position or the opening position of the at least one flow rate control element 20 is exceeded. Alternatively or additionally, provision can also be made for measures to be taken below a limit value for the monitored flow rate of the extracted at least one partial stream 16 through the membrane filtration device 18.

As a measure, at least: the reverse flushing is carried out with reversal of the flow direction of the filter module or of a plurality of or all filter modules of the membrane filter arrangement 18, as explained in the exemplary embodiment according to fig. 2 for the purification device 17 or for the partially illustrated pasteurization device 1. The same reference numerals or component names as in the above-described fig. 1 are used for the same components in fig. 2. To avoid unnecessary repetition, reference is made to or incorporated into the detailed description set forth above in connection with FIG. 1.

As shown in fig. 2, the membrane filtration device 18 of the purification device 17 may comprise a plurality of filtration modules 24, wherein fig. 2 shows 4 filtration modules 24 purely by way of example. The number of filter modules 24 and the filter capacity of the filter modules 26 can be selected accordingly as a function of the expected degree of contamination and/or adapted to the volume of the treatment liquid which is guided through the pasteurization device 1 overall during operation. In principle, the filter modules 24 of the membrane filter arrangement 18 can be arranged in any desired manner in the membrane filter arrangement 18, for example in series in flow terms. In the exemplary embodiment shown in fig. 2, the filter modules 24 are arranged in flow connection with one another, so that a partial quantity of the partial flow 16 can be conducted past or through the filter modules 24.

The design of the individual filter modules 24 can in principle also be selected at will, as long as the tempered aqueous treatment liquid can be filtered thereby. The filtration module 24 can, for example, have a plurality of hollow fiber membranes, which can be arranged in the retentate space 25 on the supply side. The hollow fiber membrane may have pores with a pore diameter of between 0.01 μm and 0.5 μm, for example, so as to be suitable for microfiltration or ultrafiltration. The respective open ends of the hollow fiber membranes of the filter module 24 can be inserted into a sealing device 26, so that the open ends or the inner cavities of the hollow fibers open into a filtrate or permeate space 27 of the filter module 24. The sealing means 26 can here sealingly separate the retentate space 25 from the permeate space 27, so that the at least one partial stream 16 of the aqueous treatment liquid can only pass from the retentate space 25 of the filtration module 24 into the permeate space 27 by passing through the hollow fiber membrane walls from outside the hollow fiber membranes into the hollow fiber lumens. At this point the at least one partial stream 16 is filtered and particulate or coagulated impurities are retained on the retentate side.

As further shown in fig. 2, the filter modules 24 of the membrane filtration device 18 can be connected, as required, in a blockable or flow-through manner to a source 28 of a backwash liquid on the permeate or filtrate side and to an outflow 29 on the retentate or supply side, respectively. In this way, the filter modules 24 of the membrane filter device 18 can be cleaned with a reverse flow of rinsing liquid, with the flow direction through the filter modules 24 being reversed, in order to clean the filter membranes, for example hollow fiber membranes. The filter residue can be removed from the filter membrane on the retentate side, for example, in this way. In this case, for example, it can be provided that all filter modules 24 of the membrane filter arrangement 18 are cleaned together. Alternatively, it is also possible to connect the filter module groups or even each filter module 24 individually selectively in a blockable or flow-through manner to the upstream flushing liquid source 28 and the outflow 29, as is also shown in fig. 2. As the counter-current flushing liquid, for example, clean fresh water can be used, to which chemical cleaning agents can be added if necessary.

It can furthermore be provided that the filtration modules 24 of the membrane filtration device 18 are supplied with a gas stream on the retentate side in a circulating manner or as required. To this end, the filter module 24 may be connected to a gas source 30, for example a blower or a compressor line. In principle, each filter module 24 can be selectively blockable or passable, individually or in groups of filter modules 24, respectively, in line with the gas source 30 via a blocking member 31. In the exemplary embodiment shown in fig. 2, all filter modules 24 of the membrane filter arrangement 18 are selectively connectable or fluidically connectable to a gas source 30 via a common shut-off element 31.

In particular, it can be provided that the filtration modules 24 of the membrane filtration device 18 are loaded with the gas flow on the retentate side during the countercurrent flushing process. This can effectively assist the cleaning process of the filter module in the case of a back-flow flushing.

As can be seen from the exemplary embodiment according to fig. 2, it can also be provided that the flow or volume flow of the treatment liquid through the individual filter modules 24 of the membrane filter device 18, for example two filter modules 24 or groups of filter modules 24 shown on the left in fig. 2, for example groups of two filter modules 24 shown on the right in fig. 2, is continuously monitored by means of a corresponding sensor device 19, for example having a flow sensor 22. The measured flow rates through the individual filter modules 24 or groups of filter modules 24 are added to one another to form the total flow rate through the membrane filtration device 18.

Furthermore, as shown in fig. 2, it can also be provided here that, below a limit value for a respectively defined flow rate through a single filter module 24 or a group of filter modules 24, the respective individual filter module 24 or the respective group of filter modules 24 is flushed back with reversal of the flow direction. This is possible in the exemplary embodiment shown in fig. 2, since the two filter modules shown on the left and the group of two filter modules 24 shown on the right can each be selectively set to be blocked or flowable through, independently of one another, with respect to the source 28 and the outflow 29 of the backflushing liquid or with respect to the circulation circuit 11, via the blocking means 32.

In principle, it is also conceivable to influence the flow rate or the volume flow of the treatment liquid through a single filter module 24 or a group of filter modules 24, respectively, by means of a separate flow rate control device 20, as is also shown in fig. 2. The respective throughflows through the individual filter modules 24 are here summed up to the total throughflow of the at least one partial stream 16 taken from the at least one circulation loop 11 through the membrane filtration device 18. The flow control means 20 provided for this purpose can also be used here as blocking means 32 with respect to the circuit 11.

In a preferred embodiment of the method, it can be provided that the flow rate of the at least one partial stream 16 through the membrane filtration device 18 and/or the flow rate regulation or opening position of the at least one flow rate regulation means 20 is recorded, i.e. recorded over a defined period of time. The recorded flow data of the at least one partial stream 16 over the time and/or the recorded flow control position or opening position data of the at least one flow control means 20 over the time can advantageously provide information about the state of the at least one purification device 17 or membrane filtration device 18. Conclusions about the state of the treatment liquid or the quality of the treatment liquid can also be drawn in this way. In particular, the contents of various components in the treatment liquid, such as turbidity, condensate, dust or other particulate impurities, microorganisms or sludge-like substances, can be estimated on the basis of these recorded data. A very strong proliferation or abnormal growth of the microbial community over time can be identified, for example, by an abnormal decrease in the flux or an abnormal increase in the flux-regulating or opening position.

It can further be provided here that measures are taken when an atypical change in the method of monitoring the flow rate of the at least one partial flow 16 or when an atypical change in the method of the flow rate control position or the open position of the at least one flow rate control element 20 is detected. Thus, for example, atypical changes deviating from the normal operation of the at least one purification device 17 or membrane filtration device 18 can be recognized on the basis of an analysis of the course of the temporal change of the recorded data. The normal operation of the membrane filtration device 18 can be represented, for example, by a periodically slightly fluctuating flow control or open position of the at least one flow control element 20 on the basis of alternating filtration operation and backwashing operation. If a different temporal course of the recorded data is detected or detected, that is to say an atypical change in the method of the temporal course of the recorded flow and/or the flow control position or the opening position, measures can be taken or introduced accordingly.

For example, provision can be made for at least one chemical to be added to the treatment liquid as a measure. This can be done, for example, for dissolving condensed substances or for changing or adjusting the chemical composition or other parameters of the treatment liquid. An unsuitable pH value of the treatment liquid may for example lead to undesired flocculation of other components or to undesired interactions with the container. Corrosive components generally lead to the detachment of the apparatus, for example the pasteurization device 1 itself. Furthermore, hardeners may, for example, lead to coagulation or the formation of undesirable particles. In addition, the corresponding growth or proliferation rate of microorganisms, for example bacterial colonies or algae, which may be increased, for example, by dissolved nutrients in the treatment liquid, is to be taken into account. This may even be further promoted by other parameters of the treatment liquid, such as elevated temperature levels. The at least one chemical is especially selected from the group comprising pH regulators, softeners, corrosion inhibitors, surfactants and antimicrobial actives. The chemicals can be added to the treatment liquid, for example, via the means 14 or lines shown in fig. 1 or in another manner or at another location.

In principle, it is also possible to detect damage to the at least one purification device 17 or the membrane filtration device 18, for example a damaged filter module 24, or other conditions atypical of the pasteurization system 1 itself, on the basis of the recorded flow data through the membrane filtration device 18 and/or the flow control position or open position data of the at least one flow control element 20. It can therefore also be provided that, as a measure, maintenance of the purification device 17 or of the pasteurization installation 1 is carried out.

The at least one purification device 17 of the pasteurization installation 1 can generally also comprise further purification modules for further purification of the at least one partial stream 16 or for removing further undesired impurities from the at least one partial stream 16, as is schematically illustrated in fig. 2. The further purification module 33 can comprise, for example, an ion exchange device 34 or, for example, an adsorption device 35, by means of which, for example, dissolved substances can also be removed from the treatment liquid.

Finally, fig. 3 shows in part a further embodiment of the pasteurization device 1, which is advantageous for the continuous reuse and maintenance of the treatment liquid 4 clean. The same reference numerals or component names as in the preceding fig. 1 and 2 are used for the same components in fig. 3. To avoid unnecessary repetition, reference is made to or incorporated into the detailed description set forth above in fig. 1 and 2.

As can be seen from this exemplary embodiment of the pasteurization device 1 shown in detail in fig. 3, it can be provided that the pasteurization device 1 comprises a cooling device 36 with a heat exchanger 37 through which the treatment liquid 4 can flow as required. In this way, a partial volume flow of the process liquid 4 can be guided through the heat exchanger 37 of the cooling device 36 as required.

Such a cooling device 36 is usually required in a pasteurization installation for cooling a portion of the treatment liquid 4, and the cooled treatment liquid 4 can be used, for example, for cooling a container after pasteurization. By providing the heat exchanger 37, it is possible to effectively prevent impurities from entering the treatment liquid 4, for example, by the conventional air-cooled cooling tower 36 or in the conventional air-cooled cooling tower 36.

As shown in fig. 3, it can be provided, for example, for cooling a partial quantity of the treatment liquid 4, if necessary for transferring the partial quantity of the treatment liquid 4 from the circulation circuit 11 by means of the conveying device 12 into a treatment liquid reservoir 38, for example a collecting container or the like. The treatment liquid 4 can likewise be pumped from the treatment liquid reservoir 38, if required, by means of a further conveying device 12, through the heat exchanger 37 of the cooling device 36, for example cooled by cooling air, and fed back into the treatment liquid reservoir 38 again. Fig. 3 shows by way of example a cooling tower 39 as the cooling device 36, which cooling tower 39 can be supplied with a cooling liquid 41 via a cooling circuit 40. The cooled treatment liquid 4 from the treatment liquid reservoir 38 can be supplied to the circulation circuit 11 which is shown by way of example in fig. 3.

The method measures presented in this document can in principle be carried out partly manually. Preferably, the measures are carried out at least largely automatically by means of one or more signal-connected control devices.

The examples show possible embodiment variants, wherein it is to be noted here that the invention is not limited to the specifically illustrated embodiments of the invention, but that different combinations of the individual embodiments with one another are also possible and that such variant possibilities are within the reach of a person skilled in the art on the basis of the teaching of the invention for technical treatment.

Individual features or combinations of features of the different embodiments shown and described may constitute independent inventive solutions. The purpose of these separate inventive solutions can be derived from the description.

In the present description, all statements made with respect to numerical ranges are to be understood such that they include any and all subranges therein at the same time, for example statements 1 to 10 are to be understood such that all subranges based on a lower limit of 1 and an upper limit of 10 are included at the same time, i.e. all subranges beginning with a lower limit of 1 or more and ending with an upper limit of 10 or less, for example 1 to 1.7, or 3.2 to 8.1, or 5.5 to 10.

For compliance with the regulations, it is finally pointed out that the elements are in part not shown to scale and/or are shown exaggerated and/or reduced in size for a better understanding of the construction.

List of reference numerals

1 pasteurization installation

2 treatment zone

3 supply mechanism

4 treating liquids

5 outer side

6 container

7 conveying device

8 conveying belt

9 direction of conveyance

10 bottom zone

11 circulation loop

12 conveying mechanism

13 mechanism

14 mechanism

15 heating device

16 partial flow

17 purification device

18 membrane filtration device

19 sensor device

20 flow regulating mechanism

21 pump

22 flow sensor

23 differential pressure sensor

24 filtration module

25 retentate space

26 sealing mechanism

27 permeate space

28 source of counterflow rinse liquid

29 outflow opening

30 gas source

31 blocking member

32 blocking mechanism

33 purification module

34 ion exchange device

35 adsorption device

36 cooling device

37 heat exchanger

38 treatment liquid reservoir

39 cooling tower

40 cooling circuit

41 Cooling liquid

Claims (21)

1. Method for operating a pasteurization installation (1), comprising: conveying the closed containers (6) filled with the food product through one or more treatment zones (2); treating the containers (6) with the temperature-regulated, aqueous treatment liquid (4) in the one or more treatment zones (2) by applying the treatment liquid (4) to the outer side (24) of the containers (6), wherein at least a part of the treatment liquid (4) from the treatment zones (2) is returned to the treatment zones (2) in at least one circulation circuit (11) by means of a conveying means (12) for reuse, and at least one partial quantity of the volume flow of the treatment liquid (4) conducted in the at least one circulation circuit (11) is extracted per unit time to form at least one partial flow (16), which partial flow (16) is conducted through a purification device (17) which is fluidically connected to the at least one circulation circuit (11) and comprises a membrane filtration device (18) having one or more filtration modules (24) and is filtered by means of the purification device, characterized in that the flow rate of the at least one partial stream (16) through the membrane filtration device (18) is continuously monitored by means of a sensor device (19) and, on the basis of the monitoring, the partial quantity of the treatment liquid (4) extracted per unit time from the at least one circulation circuit (11) is influenced in respect of the desired flow rate of the at least one partial stream (16) through the membrane filtration device (18) by adjusting the flow rate adjustment position of at least one adjustable flow rate adjustment means (20) relative to the membrane filtration device (18), wherein the at least one partial stream (16) is reintroduced back into the circulation circuit (11) or the treatment zone (2) after passing through the purification device (17).

2. Method according to claim 1, characterized in that the desired flow rate of the at least one partial stream (16) through the membrane filtration device (18) is selected from the range between 0.1% and 50% with respect to the volumetric flow of the treatment liquid (4) in the at least one circulation loop (11) before extracting the partial stream (16).

3. Method according to claim 1 or 2, characterized in that the partial quantity of treatment liquid (4) extracted per unit time from the at least one circulation circuit (11) is influenced in terms of the desired flow rate of the at least one partial stream (16) through the membrane filtration device (18) by adjusting the degree of opening of the at least one adjustable flow regulating means (20) relative to the membrane filtration device (18).

4. Method according to claim 1, characterized in that the flow regulating position or the open position of the at least one adjustable flow regulating means (20) relative to the membrane filtration device (18) is continuously monitored.

5. Method according to claim 4, characterized in that measures are taken when a limit value in the flow regulating position or the opening position of the at least one adjustable flow regulating means (20) is exceeded.

6. Method according to claim 1, characterized in that measures are taken below a limit value for the monitored flow of the extracted at least one partial stream (16) through the membrane filtration device (18).

7. The method as claimed in claim 5 or 6, characterized in that as a measure a backwashing is carried out with reversal of the flow direction of the filter module or filter modules or all filter modules (24) of the membrane filtration device (18).

8. Method according to claim 1, characterized in that the flow of the extracted partial stream (16) is monitored by means of a sensor device (19) comprising a flow sensor (22).

9. Method according to claim 1, characterized in that the pressure loss over the membrane filtration device (18) is continuously monitored by means of a sensor device (19) comprising one differential pressure sensor (23) or at least two pressure sensors.

10. Method according to claim 1, characterized in that the flow of the treatment liquid (4) through the filter modules (24) or groups of filter modules (24) of the membrane filtration device (18) is continuously monitored by means of a sensor device (19), respectively, wherein the flow through the filter modules (24) or groups of filter modules (24) is added up to the total flow through the membrane filtration device (18).

11. Method according to claim 10, characterized in that, when the flow rate through a single filter module (24) or a group of filter modules (24) is below a respective determined limit value, the respective single filter module (24) or the respective group of filter modules (24) is backflushed with reversal of the flow direction.

12. Method according to claim 1, characterized in that a gas flow is applied to the filtration modules (24) of the membrane filtration device (18) on the retentate side periodically or as required.

13. Method according to claim 12, characterized in that a gas flow is applied to the filtration module (24) of the membrane filtration device (18) on the retentate side during the back-flow flushing process.

14. Method according to claim 1, characterized in that the flow of the at least one partial stream (16) through the membrane filtration device (18) over a period of time and/or the flow regulating position or opening position of the at least one adjustable flow regulating means (20) is recorded.

15. Method according to claim 14, characterized in that measures are taken when a method atypical change of the monitored flow of the at least one partial flow (16) is detected or when a method atypical change of the flow regulating position or the opening position of the at least one adjustable flow regulating means (20) is detected.

16. The method according to claim 15, characterized in that as a measure at least one chemical selected from the group comprising pH regulators, softeners, corrosion inhibitors, surfactants and antimicrobial actives is incorporated into the treatment liquid (4).

17. Method according to claim 15, characterized in that as a measure, the purification device (17) or the pasteurization installation (1) is serviced.

18. Method according to claim 1, characterized in that the food in the container (6) is heated in one treatment zone (2) or gradually heated in a plurality of treatment zones (2), whereupon the food in the container is pasteurized in one treatment zone (2) or in a plurality of treatment zones (2), and thereafter the food in the container is cooled in one treatment zone (2) or gradually cooled in a plurality of treatment zones (2).

19. Method according to claim 18, characterized in that the at least one partial stream (16) is extracted from the circulation loop (11) of the flow of treatment liquid (4) having a temperature level between 20 and 60 ℃.

20. Method according to claim 1, characterized in that a partial volume flow of the treatment liquid (4) is conducted through the heat exchanger (37) of the cooling device (36) as required.

21. A pasteurization apparatus comprising: one or more treatment zones (2) having supply means (3) for applying a tempered treatment liquid (4) onto the outside (5) of a closed container (6) filled with food; -conveying means (7) for conveying the containers (6) through the treatment zone (2); at least one circulation circuit (11), wherein at least a part of the treatment liquid (4) from the treatment zone (2) can be returned in the at least one circulation circuit (11) by means of a conveying device (12) into the treatment zone (2) again for reuse; and a purification device (17) which is connected in line with the at least one circuit (11) in terms of flow technology and comprises a membrane filtration device (18) having one or more filtration modules (24), through which purification device (17) at least one partial stream (16) can be conducted and can be filtered, characterized in that a sensor device (19) is provided, by means of which the flow rate of the at least one partial stream (16) through the membrane filtration device (18) can be continuously monitored, and at least one adjustable flow rate regulating element (20) is provided, on the basis of which, by adjusting the flow rate regulating position of the at least one adjustable flow rate regulating element (20) relative to the membrane filtration device (18), the point extracted from the at least one circuit (11) per unit of time can be influenced in terms of the desired flow rate of the at least one partial stream (16) through the membrane filtration device (18) A partial quantity of the treatment liquid (4), wherein the at least one partial flow (16) can be reintroduced back into the circulation circuit (11) or the treatment zone (2) after passing through the purification device (17).