Patent ID: 12185745

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

First of all, it is to be noted that, in the different embodiments described, equal parts are provided with equal reference numbers and/or equal component designations, where the disclosures contained in the entire description may be analogously transferred to equal parts with equal reference numbers and/or equal component designations. Moreover, the specifications of location, such as at the top, at the bottom, at the side, chosen in the description refer to the directly described and depicted FIGURE, and in case of a change of position, these specifications of location are to be analogously transferred to the new position.

FIG.1schematically represents an exemplary embodiment of a pasteurizing device1for pasteurizing foods filled into sealed containers2. The pasteurizing device1comprises multiple treatment zones3with sprinkling means4for applying a treatment liquid5to an exterior6of the sealed containers2. In the exemplary embodiment in accordance withFIG.1, purely by way of example and for better clarity, merely five treatment zones3are represented, wherein it should be understood that, depending on the requirement and design of a pasteurizing device1, also fewer or more treatment zones3can be provided. For example, pasteurizing devices with 10, 15 or more treatment zones3are absolutely customary.

During operation of the pasteurizing device1, a pasteurizing of foods is carried out such that the foods are filled into the containers2in advance, and the containers2are sealed. A treatment of the containers2which are filled with foods and sealed is carried out in a respective treatment zone3by applying an aqueous treatment liquid5to an exterior6of the containers2via the sprinkling means4. The sprinkling means4of a respective treatment zone3can be formed by sprinkler or nozzle-type sprinkling means, for example, and/or generally by means for dissipating the treatment liquid in a respective treatment zone3. The tempered, aqueous treatment liquid5is applied to the exterior6of the containers2in this manner, whereby the containers2, and therefore the foods filled into the containers2, can be selectively tempered and pasteurized. The containers2can be formed, for example, by bottles, cans or other containers and generally be composed from various materials, and optionally be coated or printed. It may in particular be provided in the method that the foods to be pasteurized are filled into containers2comprising a metal, in particular aluminum, such as bottles with a seal comprising a metal. In particular, the containers2can be formed by aluminum drink cans2, such as this is also indicated inFIG.1.

A transport means7for transporting the containers2through the treatment zones3is provided. In the exemplary embodiment represented inFIG.1, the transport means7comprises two driven conveyor belts8, with the help of which the containers2which are filled with foods and sealed are transported through the treatment zones3on two levels during operation of the pasteurizing device1. This may be done in a transport direction9, for example from left to right, illustrated by means of the arrows inFIG.1.

During operation of a pasteurizing device1, it may be provided, for example, that the foods in the containers2are initially warmed up in a treatment zone3or in multiple treatment zones3, heated to, and maintained at, pasteurizing temperature, following in transport direction8, in one or multiple treatment zones3and subsequently selectively cooled down, following in transport direction9, in one or multiple treatment zones3.

In the exemplary embodiment of a pasteurizing device1represented inFIG.1, viewed in transport direction9, initially two treatment zones3configured as a warm-up zones10,11are provided by way of example, in which two treatment zones3the foods and/or containers2are initially successively pre-heated during operation of the device1. In the represented exemplary embodiment, a pasteurizing zone12for pasteurizing the foods is provided in transport direction9toward the warm-up zones10,11. In this treatment and/or pasteurizing zone3,12, the foods are pasteurized by supplying a treatment liquid5suitably tempered for pasteurizing and by sprinkling onto the exterior6of the containers2. Following this in transport direction9, in the exemplary embodiment inFIG.1, two treatment zones3configured as cool-down zones13,14are provided, in which cool-down zones13,14the foods and/or the containers are successively cooled down by supplying a treatment liquid5with a temperature respectively suited to cool down the containers2, during operation of the pasteurizing device1.

As can be seen fromFIG.1, the pasteurizing device1comprises a feed pipe15for each treatment zone3for feeding a tempered volume flow of the treatment liquid to a respective sprinkling means4. Furthermore, the pasteurizing device1comprises tempering means16for tempering the treatment liquid5and/or for tempering individual volume flows of the treatment liquid5supplied to the treatment zones3. In the exemplary embodiment represented inFIG.1, valves17, in particular flow control valves, for example, are provided as tempering means16, via which hot treatment liquid from a warm-water tank18or cool treatment liquid from a cold-water tank19can respectively be admixed, for tempering, to some of the volume flows of the treatment liquid5supplied to a treatment zone3. In addition, as represented inFIG.1, a heating means20, for example a heat exchanger such as a hot-steam heat exchanger, can be provided as a general tempering means16for warming up and/or heating the treatment liquid. Equally, a cooling means21, for example a cold-water heat exchanger, can be provided for the general cooling down of the treatment liquid5. During operation of the pasteurizing device1, treatment liquid5with a specific temperature can be supplied to each treatment zone3by means of such tempering means16via the respective feed pipe15.

During operation of the pasteurizing device1represented inFIG.1as an exemplary embodiment, treatment liquid5with a temperature of 25° C. to 45° C., for example, can be supplied to the warm-up zone10arranged first in transport direction9. Treatment liquid5with a temperature level of 45° C. to 65° C., for example, can be supplied, following in transport direction9, to the warm-up zone11. Treatment liquid5with a temperature of 65° C. to 95° C. can be supplied to the pasteurizing zone12. Treatment liquid with a temperature of 40 to 60° C., for example, can be supplied to the cool-down zone13arranged downstream of the pasteurizing zone12in transport direction9and treatment liquid with a temperature level of 25 to 40° C. can be supplied to the cool-down zone14arranged following same in transport direction9. Depending on different configurations of a pasteurizing device, such as the number of treatment zones, or also depending on the type of a food and/or its requirements, also other temperatures can be selected for the treatment zones3, of course.

The pasteurizing device1represented inFIG.1comprises collection elements22in each treatment zone3, such as collection tubs arranged in a bottom base region of the treatment zones3, for collecting the treatment liquid5after its application to the containers2. Furthermore, a circulation circuit23with circulation circuit pipes24and conveying means25is provided in the treatment zones3for reuse of the treatment liquid5by re-supplying the collected treatment liquid5. The circulation circuit pipes24can be formed by pipes and the conveying means25by conveying pumps. During operation of the pasteurizing device1, these are used to collect the treatment liquid5in the treatment zones3after application to the containers2, and the collected treatment liquid5is re-supplied to at least one treatment zone3for reuse via circulation circuit pipes24of a circulation circuit23.

In the exemplary embodiment represented inFIG.1, the circulation circuit23is configured such that the treatment liquid of the pasteurizing zone12can be fed back again into the pasteurizing zone12in a circle. The treatment liquid5collected in the cool-down zones13and/or14can be supplied to the warm-up zones11and/or10during operation of the pasteurizing device1via circulation circuit pipes24and/or recuperation pipes. Conversely, as can be seen fromFIG.1, the treatment liquid collected in the warm-up zones10and/or11can be supplied to the cool-down zones14and/or13via circulation circuit pipes24and/or recuperation pipes. It is advantageous here that, due to the cooling down of the treatment liquid5by the pre-heating of the containers2in the warm-up zones11,12, the collected treatment liquid5has a temperature level respectively suited for the cool-down zones13and/or14. Conversely, this also applies to the treatment liquid5warmed up by the cooling down in the cool-down zones13and/or14with regard to the zones12and/or11. Yet partial quantities of the treatment liquid5collected in the treatment zones3can also be supplied to the water tanks18,19and be replaced with treatment liquid from these water tanks18,19. This can serve in particular to manipulate a respective temperature of the treatment liquid5for feeding into the treatment zones3via the feed pipes15.

Evidently, a circulation circuit23of a pasteurizing device1may also be configured differently in detail than in the exemplary embodiment represented inFIG.1. For example, circulation circuit pipes24leading from one treatment zone3to another treatment zone3may not be provided, but instead, for example, a circulation around individual zones3, or a circulation via treatment liquid collection tanks. Quite generally, the invention is not limited to specific circulation circuit routings and/or configurations but can be used in any kind of configuration of a circulation circuit23.

As can be seen fromFIG.1, the pasteurizing device1comprises at least one liquid-removal means26for continuously removing a partial quantity of treatment liquid5from the circulation circuit23or from a treatment zone3. This liquid-removal means26is connected, in terms of flow dynamics, with a feeding pipe27of at least one bypass28.

Furthermore, a membrane filtration means29arranged in the bypass28is configured, wherein the feeding pipe27of the at least one bypass28is provided for supplying a removed partial flow of the treatment liquid5to the membrane filtration means29arranged in the at least one bypass28. A discharge pipe30of the at least one bypass28, which discharge pipe30is connected with the circulation circuit23or with a treatment zone3, for re-supplying a filtered partial flow of the treatment liquid5into a treatment zone3and/or into the circulation circuit23is equally provided, as can be seen fromFIG.1.

During operation of the pasteurizing device1, a partial quantity of treatment liquid5is continuously removed, by means of a liquid-removal means26, from the treatment liquid5circulated in the circulation circuit23or from treatment liquid5in a treatment zone3for forming at least one partial flow of the treatment liquid5, and this at least one partial flow is supplied and filtered via the feeding pipe27of at least one bypass28of a membrane filtration means29arranged in the at least one bypass28. Subsequently, a partial flow thus purified is fed back again into the circulation circuit23or into a treatment zone3.

Quite generally, a removal of a partial quantity of treatment liquid for supplying to a membrane filtration means29can be done at any point of the circulation circuit23. Equally, a removal from a treatment zone3, or also from a water tank18,19integrated in the circulation circuit23, is possible. Preferably, as also represented inFIG.1, a partial quantity for forming the partial flow of the treatment liquid5is removed from the circulation circuit23, as this renders obsolete an additional pump for removing the partial quantity of the treatment liquid. A liquid-removal means26may comprise, for example, a T-piece arranged in the circulation circuit23for separation of the liquid flow. Additionally, for controlling the continuously-removed partial quantity of treatment liquid per unit of time, a removal means26can additionally comprise a flow control valve31, for example, such as this is equally illustrated inFIG.1. Preferably, treatment liquid5with a temperature of 50° C. or less is removed for forming and routing via a bypass28.

In the exemplary embodiment represented inFIG.1, for example, treatment liquid is removed at two points and supplied to 2 bypasses28. A respective feeding pipe27of the bypasses28is connected, in the represented exemplary embodiment, with a circulation circuit pipe24leading to the warm-up zone10arranged first in transport direction9, and/or with a cool-down zone14leading to the circulation circuit pipe24arranged last in transport direction9. During operation of the pasteurizing device1, treatment liquid5with a relatively low temperature is run in these two circulation circuit pipes24. As further fromFIG.1, a filtered partial flow of the treatment liquid is preferably fed back again into a treatment zone3, which treatment zone3contains treatment liquid5with a temperature level which corresponds, at least essentially, to the temperature of the fed-back partial flow of the treatment liquid. Evidently, depending on a size of a pasteurizing device, or depending on a respective contamination level of the treatment liquid, also only one bypass, or also more than two bypasses, can be provided for the continuous purification of a partial quantity of the circulated and perpetually-reused treatment liquid.

It is further provided in the method for operating a pasteurizing device1that process chemicals are added to the treatment liquid5. Here, an addition of process chemicals can, quite generally, preferably be done in the form of concentrated, aqueous solutions.

Specifically, it is provided that a biocide selected from a group consisting of hypochlorite, peracetic acid, chlorine dioxide and bronopol, or a mixture of biocides selected from this group, is apportioned to the treatment liquid as process chemical, such that a concentration of the biocide, or a total concentration of biocides, does not exceed 0.4 mmol/L. In a preferred variant embodiment of the method, preferably chlorine dioxide can be apportioned to the treatment liquid5as biocide. Yet it may also be provided that a mixture of chlorine dioxide and hypochlorite is apportioned to the treatment liquid5.

Furthermore, it is provided that a pH-regulating agent comprising at least one inorganic or organic acid is apportioned to the treatment liquid as process chemical, such that a pH value of the treatment liquid is set to a range from 3.5 to 7.0, preferably 4.0 to 6.5.

In the method, the apportioning of process chemicals can, quite generally, be done manually, for example by operating personnel. Preferably, an apportioning of one or multiple, or also all, process chemicals added can be done by means of dosing means32, in particular controlled in an automated manner. As is represented inFIG.1and will be explained in more detail on the basis of examples, a process chemical can generally be apportioned to the treatment liquid5by means of one or multiple dosing means(s)32at one or multiple dosing points33.

In principle, an apportioning of process chemicals can be done in a time-controlled manner, for example on the basis of empirical values. Yet preferably, it may be provided in the method that an apportioning of at least one or multiple or all process chemical(s) is carried out on the basis of a measurement value of a water parameter, in particular a concentration of one or multiple substances in the treatment liquid. Here, an apportioning of a process chemical can be done on the basis of a measured concentration of the process chemical itself and/or also on the basis of a measured concentration of a different substance contained and/or dissolved in the treatment liquid5. Quite generally, a measurement of a concentration of a substance contained and/or dissolved in the treatment liquid or a concentration of a process chemical can, again, be carried out manually here, for example by operating personnel of the pasteurizing device1.

Yet in particular, as represented inFIG.1, it may preferably be provided that at least one actual value of a concentration of at least one chemical substance contained in the treatment liquid5and/or of at least one process chemical added and/or of at least one internal standard added is detected by means of at least one concentration measurement sensor34at at least one measurement point35and/or measurement section35, and, on the basis of the actual value detected by means of the at least one concentration measurement sensor34at the at least one measurement point35and/or measurement section35, a concentration of the at least one contained chemical substance and/or of the at least one process chemical added is manipulated, with regard to a specifiable target value for the concentration of the at least one chemical substance contained in the treatment liquid and/or of the at least one process chemical added and/or of the at least one internal standard added, by apportioning at least one process chemical and/or the at least one process chemical added at at least one dosing point33by means of at least one dosing means32.

In the exemplary embodiment of a pasteurizing device1represented inFIG.1, concentration measurement sensors34are represented at multiple measurement points35and/or measurement sections35to that end, by means of which concentration measurement sensors34an actual value of a concentration of one or multiple process chemicals can respectively be detected. Quite generally, it may also be expedient here to detect an actual value of the concentration of a specific chemical substance contained and/or dissolved in the treatment liquid5, and/or of a specific process chemical added and/or of a specific internal standard added by means of one respective concentration measurement sensor34also at multiple measurement points35. Examples of suitable and/or preferred solutions for the detection of concentrations will be explained below.

In the exemplary embodiment of a pasteurizing device1represented inFIG.1, dosing means32arranged at multiple dosing points33are further represented. A dosing means32can preferably be configured, as is generally known, for apportioning a concentrated, aqueous solution of one or multiple process chemical(s), with known concentration of the process chemical(s). To that end, a dosing means32can comprise a dosing valve, for example. Alternatively, also an apportioning of solid or gaseous process chemicals is generally possible, of course.

In the exemplary embodiment represented inFIG.1, a dosing means32can generally be provided for apportioning only one process chemical. Yet it may evidently also be provided that multiple process chemicals are apportioned to the aqueous treatment liquid by means of one dosing means32. Here, advantages may arise for different process chemicals depending on a respectively selected dosing point33, for example, as will be explained in more detail below.

An addition of an internal standard of known concentration and/or quantity to the treatment liquid can generally be done separately from the addition of the process chemical(s). Preferably, however, an internal standard is admixed to the treatment liquid together with at least one process chemical, and in particular together with one or multiple process chemical(s) whose concentration is to be inferred on the basis of the detection of the concentration of the internal standard. In particular, a process chemical and an internal standard can therefore be apportioned to the treatment liquid together by means of one or multiple dosing means32. Such an added internal standard enables, in particular, a loss in process chemical(s), for example due to the sprinkling of the containers and/or due to evaporation of the treatment liquid, as elaborated above, to be acquired in particular in a pasteurizing zone and by replacement with fresh treatment liquid.

A colorant, in particular a fluorescent dye, for example, can be apportioned as internal standard. Reference is made to fluorescein, a rhodamine or preferably 1,3,6,8-Pyrenetetrasulfonic acid, sodium salt (PTSA) as suitable internal standards. A detection of an actual value of the concentration of an internal standard can then be done by measuring a fluorescence, for example, in case of a respective fluorescence wavelength of the internal standard, and concentration measurement sensors34configured as fluorescence measurement sensors36, for example, can be arranged in the pasteurizing device1to that end. A detection of the concentration of an internal standard, for example by means of such fluorescence measurement sensors36, can be done, in this case, preferably at multiple measurement points35, as this is also illustrated inFIG.1.

Generally, the apportioning of all process chemicals added can be done on the basis of one or multiple detected actual value(s) of the concentration of an internal standard by specifying one or multiple respective target value(s). However, as this enables a loss in process chemicals to be acquired only due to a loss of the treatment liquid as such, as has been elaborated above, a higher apportioning of the process chemical(s) than results purely by calculation from a detected actual value of the concentration of an internal standard can be carried out in this case. Furthermore, a direct detection of an actual value of the concentration may be advantageous, at least for some process chemicals. As equally described, this applies in particular to process chemicals whose concentration continuously decreases on the basis of chemical reactions in the treatment liquid5, in particular on the basis of reactions with microorganisms or substances contained and/or dissolved in the treatment liquid.

Quite generally, a specification, on the basis of one or multiple actual value(s), of one or multiple target value(s) for a concentration of the at least one chemical substance contained in the treatment liquid and/or of the at least one process chemical added and/or of the at least one internal standard added can, of course, be done in a variable manner. Furthermore, it is also absolutely possible to specify different target values for the concentration of the at least one chemical substance contained in the treatment liquid and/or of the at least one process chemical added and/or of the at least one internal standard added for different measurement points35and/or measurement sections35.

Furthermore, as represented inFIG.1, at least one process chemical can, quite generally, be apportioned by means of at least one dosing means32at at least one dosing point33arranged in the circulation circuit23or in a treatment zone3. It may also be useful, in particular depending on the type of a process chemical, if at least one process chemical is apportioned to the treatment liquid by means of a dosing means32at at least one dosing point33arranged in a feed pipe37for fresh treatment liquid. Examples of preferred dosing points33for specific process chemicals will be explained in more detail below on the basis of the exemplary embodiment in accordance withFIG.1.

As is further represented inFIG.1, it may be provided in the method that at least one actual value of the concentration of at least one contained chemical substance and/or of at least one process chemical added and/or of at least one internal standard added is detected by at least one concentration measurement sensor34at at least one measurement point35arranged in the circulation circuit23or in a treatment zone3. Equally, it is also possible here, of course, to detect a respective actual value by means of at least one concentration measurement sensor34at at least one measurement point35arranged in the feed pipe37. This may be the case in particular with regard to a detection of an actual value of a concentration of a chemical substance contained and/or dissolved in the fresh treatment liquid and/or in a fresh water.

An execution of the method may also be expedient in which a first actual value and a second actual value of the concentration of at least one contained chemical substance and/or of at least one process chemical added and/or of at least one internal standard added is detected in the treatment liquid by means of a first concentration measurement sensor34and by means of a second concentration measurement sensor34at at least two measurement points35spaced apart from one another, as this is schematically apparent fromFIG.1. Subsequently, on the basis of the actual value detected by means of the first concentration measurement sensor34and/or on the basis of the actual value detected by means of the second concentration measurement sensor34, a concentration of the at least one contained chemical substance and/or of the at least one process chemical added can be manipulated, with regard to a specifiable target value for the concentration of the at least one chemical substance contained in the treatment liquid and/or of the at least one process chemical added and/or of the at least one internal standard added. In this context, it may be of advantage, for example, if the first actual value is detected by means of a first concentration measurement sensor34arranged adjacent to a dosing means32upstream in relation to a flow direction of the treatment liquid, and the second actual value is detected by means of a second concentration measurement sensor34arranged spaced at least 5 meters apart from the first concentration measurement sensor34upstream in relation to a flow direction of the treatment liquid.

With regard to the measurement of a concentration by means of a concentration measurement sensor as well as the apportioning of process chemicals by means of dosing means, advantages may arise as a result of certain, specific executions of the method, which advantages will be described in more detail below on the basis of exemplary embodiments.

For example, it may be of advantage that the biocide, in particular chlorine dioxide, is apportioned to a volume flow of the treatment liquid5, which volume flow of the treatment liquid5is run in a circulation circuit pipe24leading, in terms of flow dynamics, to a cool-down zone14, such as this is also represented inFIG.1. As is equally represented inFIG.1, the biocide can be apportioned to the treatment liquid5, quite generally, at at least one dosing point33arranged in the circulation circuit23or in a treatment zone3, at which dosing point33treatment liquid5is run at a temperature of 20° C. to 55° C. In this case, in the exemplary embodiment represented inFIG.1, a biocide, in particular chlorine dioxide, can be apportioned by means of the dosing means32,38represented. These measures are useful in particular because the conditions in such areas of a pasteurizing device1particularly facilitate a formation of biofilms due to a high reproduction of microorganisms. Preferably, biocide can be apportioned to the treatment liquid by means of at least one dosing means32,38at at least one dosing point33and/or at at least one dosing section33, at which dosing point33or at which dosing section33treatment liquid5is run at a temperature of 30° C. to 45° C.

In addition, as equally represented inFIG.1, the biocide can be apportioned to the treatment liquid5at at least one dosing point33arranged in the at least one bypass28downstream, in terms of flow dynamics, of a membrane filtration means29, such as this is illustrated on the basis of the respectively-positioned dosing means32,38represented inFIG.1.

As is apparent fromFIG.1, at least one actual value of the biocide concentration in the treatment liquid5can, quite generally, be detected by means of at least one biocide concentration measurement sensor34,39at at least one measurement point35, and, on the basis of the actual value detected at the at least one measurement point35, a concentration of the biocide in the treatment liquid5can be manipulated, with regard to a specifiable target value for the concentration of the biocide, by apportioning the biocide by means of at least one dosing means32,38at at least one dosing point33. At least one actual value of the biocide concentration can be detected here at at least one measurement point35arranged in the circulation circuit23or in a treatment zone3, at which measurement point35treatment liquid5is run at a temperature of 20° C. to 55° C., such as this is illustrated on the basis of the respectively-positioned concentration measurement sensors34,39. Quite generally, it may be of advantage if multiple actual values of a biocide concentration in the treatment liquid5are detected by means of multiple biocide concentration measurement sensors34,39at multiple measurement points35of a pasteurizing device1, for example in the circulation circuit23and/or its circulation circuit pipes24and/or treatment zone(s)3, such as this is equally represented inFIG.1. Preferably, it may be provided that at least one actual value of the biocide concentration is detected by means of at least one concentration sensor34,39at at least one measurement point35and/or at at least one measurement section35, at which measurement point35and/or at which measurement section35treatment liquid5is run at a temperature of 30° C. to 45° C.

In case of an apportioning of chlorine dioxide as biocide, at least one actual value of a chlorine dioxide concentration can be detected by means of a concentration measurement sensor34configured for determining chlorine dioxide at at least one measurement point35and/or measurement section35. Concentration measurement sensors34for measuring a chlorine dioxide concentration are generally known. Generally, a chlorine dioxide concentration can be detected by means of different measurement methods and/or measurement principles. For example, amperometric, fluorometric or optical sensors34measuring a light absorption can be used. In case of an apportioning of another biocide than chlorine dioxide, another can accordingly be used for measuring the concentration of such other biocide, of course.

Preferably, when chlorine dioxide is used as biocide, a dosing means32,38or the dosing means32,38, can be connected with a provisioning means40for chlorine dioxide, as is represented in the exemplary embodiment in accordance withFIG.1. Such a provisioning means40can be configured for the chemical production and provisioning of chlorine dioxide for the dosing means32,38, so that, during operation of the pasteurizing device1, chlorine dioxide can be chemically produced in situ and provisioned for the dosing means32,38by means of the provisioning means40. Here, a provisioning means40can be configured for the chemical production of chlorine dioxide according to a method generally known, such as the hydrochloric acid/chlorite method or the persulfate/chlorite method and/or the peroxosulfate/chlorite method. Preferably, the provisioning means40can be configured for producing chlorine dioxide according to the so-called one-component solid method.

A target value of a biocide concentration, in particular chlorine dioxide concentration, can definitely be specified in a varied and/or variable manner as and when required, for example depending on the contaminant concentration and/or depending, for example, on a detected microbial count in the treatment liquid.

In the method for operating a pasteurizing device1, it may further be provided that a pH-regulating agent comprising at least one acid selected from a group consisting of phosphoric acid, formic acid, acetic acid, citric acid, gluconic acid, lactic acid, heptagluconic acid, or a mixture of acids selected from this group, is apportioned to the treatment liquid5. The pH value of the treatment liquid has a large impact on other properties of the treatment liquid, and in particular on undesired side effects caused by the treatment liquid. In the case of the treatment of containers comprising a metal, in particular containers comprising aluminum and/or aluminum cans, the pH value of the treatment liquid per se, for one thing, has proven an important parameter for impeding discolorations on the containers. Furthermore, it turned out that also the choice of the acid(s) used for pH regulation is important with regard to impeding discolorations on the containers, in particular the formation of the so-called staining.

It may in particular be provided in the method that the pH-regulating agent is apportioned to the treatment liquid5at at least one dosing point33, at which dosing point33treatment liquid5is run at a temperature of 40° C. to 90° C., such as this is represented inFIG.1on the basis of the dosing means32,41.

Furthermore, at least one actual value of a pH value of the treatment liquid can be detected by means of at least one pH measurement sensor34,42at at least one measurement point35. Subsequently, a pH-regulating agent can then be apportioned on the basis of a detected actual value of a pH value of the treatment liquid5. As is illustrated in theFIG.1, the at least one actual value of a pH value of the treatment liquid5can be detected at at least one measurement point35, at which measurement point35treatment liquid is run at a temperature of 40° C. to 90° C.

Furthermore, it may be expedient to apportion at least one complex-forming acid selected from a group consisting of gluconic acid, lactic acid, citric acid, or a mixture of acids selected from this group, to the treatment liquid as process chemical(s) in the method for operating a pasteurizing device1. This is done in such a way that a concentration of the at least one complex-forming acid, or a total concentration of the apportioned, complex-forming acids, does not exceed 2.2 mmol/L.

It may be of advantage in this context if the at least one complex-forming acid is apportioned to the treatment liquid5at at least one dosing point33, at which dosing point33treatment liquid5is run at a temperature of 55° C. to 95° C., such as this is also shown in the exemplary embodiment in accordance withFIG.1on the basis of a respectively-positioned dosing means32,43. The above-mentioned acids are generally effective as corrosion protection agents and scale prevention agents.

Additionally, it may be useful in an embodiment of the method if at least one complex-forming phosphonic acid selected from a group consisting of (1-Hydroxy-1,1-ethanediyl)bis(phosphonic acid), 3-Carboxy-3-phosphonohexanedioic acid, Diethylenetriamine pentamethylene phosphonic acid, Aminotris(methylenephosphonic acid), or at least one phosphonate of a phosphonic acid selected from this group, or a mixture of phosphonic acids and/or phosphonates selected from this group, is apportioned to the treatment liquid as process chemical(s). This is done in such a way that a concentration of the at least one complex-forming phosphonic acid or of the at least one phosphonate, or a total concentration of the apportioned, complex-forming phosphonic acids and/or phosphonates, does not exceed 0.2 mmol/L. The at least one complex-forming phosphonic acid and/or the at least one complex-forming phosphonate can be apportioned to the treatment liquid5at at least one dosing point33, at which dosing point33treatment liquid5is run at a temperature of 55° C. to 95° C., such as this is illustrated on the basis of the respectively-positioned dosing means32,43represented inFIG.1. Accordingly, the dosing means32,43can be provided in the exemplary embodiment represented inFIG.1for apportioning both a complex-forming acid and a phosphonate. Also the above-mentioned phosphonates are effective with regard to scale prevention and also corrosion protection.

Yet it may also be provided that a divalent zinc salt is apportioned to the treatment liquid as process chemical, namely such that a concentration of the divalent zinc salt does not exceed 0.06 mmol/L.

Also Zn2+salts have proven effective primarily as corrosion inhibitors and can generally be apportioned to the treatment liquid together with other process chemicals and/or corrosion inhibitors. An apportioning of a divalent zinc salt can be done, again, by means of the dosing means designated with32,43inFIG.1. Yet, quite generally, also another and/or additional dosing means can be provided to that end.

Furthermore, it may be provided that an oligomer or polymer substance selected from a group consisting of polyphosphates, water-soluble polyacrylates and copolymers of maleic acid and acrylic acid, or a mixture of oligomer or polymer substances selected from this group, is apportioned to the treatment liquid as process chemical, such that a concentration of the apportioned oligomer or polymer substance, or a total concentration of the apportioned oligomer or polymer substances, does not exceed 0.4 g/L.

These oligomer or polymer substances have proven equally effective in particular with regard to an impeding of scale formation. The respective oligomers and/or polymers can have molecular weights in the range from 4000 g/mol to 15000 g/mol, for example. Again, an apportioning of an oligomer and/or polymer substance, in the exemplary embodiment represented inFIG.1, can be done by means of the dosing means32,43, or one or multiple additional dosing means.

In addition, it may be of advantage in the method if a phosphoric ester, or a mixture of phosphoric esters, is apportioned to the treatment liquid as process chemical, such that a concentration of the phosphoric ester, or a total concentration of the phosphoric esters, does not exceed 0.1 g/L.

Phosphoric esters, per se or also in combination with other process chemicals, have, again, proven to be effective corrosion inhibitors. Also one or multiple phosphoric esters can generally be apportioned using one dosing means32,43, such as this is illustrated on the basis of the exemplary embodiment represented inFIG.1.

In particular in the context of scale prevention, it may furthermore be expedient in the method if an actual value of a water hardness of the treatment liquid is detected by means of at least one Ca2+and/or Mg2+measurement sensor34,44at at least one measurement point35. Here, sensors for detecting a Ca2+and/or Mg2+concentration may in particular comprise ion-selective electrodes. In particular, an actual value of a water hardness of the treatment liquid can be detected, by means of at least one Ca2+and/or Mg2+measurement sensor34,44, at at least one measurement point35arranged in a feed pipe37for fresh treatment liquid, such as this is illustrated inFIG.1. Subsequently, an apportioning of the above-mentioned process chemicals which are effective with regard to scale prevention and/or prevention of scale formation can be carried out on the basis of a measured actual value of the water hardness.

Furthermore, it may be provided that an actual value of a conductivity of supplied, fresh treatment liquid is detected at at least one measurement point35arranged in a feed pipe37for fresh treatment liquid.

Generally, the conductivity of the fresh treatment liquid can be detected manually by sample-taking at the measurement point and subsequent laboratory measurement. Preferably, it may be provided that the conductivity is detected by means of a concentration measurement sensor34formed by a conductivity sensor45, such as this can also be seen fromFIG.1. Here, the detection of the conductivity of the fresh treatment liquid is representative of the total concentration of dissolved ions in the freshly supplied treatment liquid.

The detection of the conductivity, therefore, provisions an actual value of dissolved, ionic substances contained in the supplied, fresh treatment liquid which may be relevant with regard to the formation of deposits or also discolorations in the course of the treatment with treatment liquid. On the basis of such a detected actual value of the conductivity of the supplied, fresh treatment liquid, a specification of target values for the concentration of process chemicals in the treatment liquid5can then be done. For example, it may be provided that a target value or target values of the conductivity for the process chemical(s) is increased upon detection of an increased and/or high actual value. Upon detection of a decreased and/or low actual value of the conductivity, the opposite can be done. It may then respectively and/or subsequently be provided that a dosage quantity of at least one process chemical is increased and/or decreased. In other words, a target value for the concentration of one or multiple process chemical(s) can be specified, at least in part or for the most part, on the basis of the detected conductivity of the supplied, fresh treatment liquid. Respectively, a dosage quantity of at least one process chemical can be adjusted with regard to a specifiable target value for a concentration of one or multiple chemical substance(s) contained in the treatment liquid, in particular Ca2+and Mg2+ions.

As is illustrated on the basis of the exemplary embodiment in accordance withFIG.1, it may also be provided in the method, in terms of safety technology, that, upon a detected exceeding of a specified target value of the concentration of an apportioned process chemical, in particular an apportioned biocide, gas atmosphere is exhausted from the treatment zones3by means of an exhaust means46operatively connected with the treatment zones3.

As equally represented inFIG.1, a control means47may be provided for the automatic control of the apportioning of the process chemical(s), as is generally known. As illustrated, such a control means47can be connected, in terms of signal engineering, in particular to the concentration measurement sensors34and dosing means32represented by way of example, but also to other and/or additional components of the pasteurizing device1.