Temperature treatment stage, method for treating a fluid and treatment plant for treating workpieces

Abstract

The invention relates to a temperature treatment stage (100) for treating a fluid, more particularly for thermally treating a treatment fluid (512) in a treatment facility (510) for treating workpieces, comprising a recuperative heat exchanger (400) having a primary side (402) and a secondary side (404), which as intended are in heat exchange with one another, and a heating stage (300) for heating the treatment fluid (512) to a target temperature, where a flow circuit (700) for the treatment fluid (512) comprises, in its flow direction (750), the primary side (402) of the recuperative heat exchanger (400), the heating stage (300) and the secondary side (404) of the recuperative heat exchanger (400). Disposed downstream of the heating stage (300) and upstream of the secondary side (404) of the recuperative heat exchanger (400) in the flow circuit (700) is a temperature hold unit (310), in which the treatment fluid (512) has a specified dwell time at the target temperature. The invention further relates to a treatment plant having such a temperature treatment stage (100) and to a method for thermally treating a treatment fluid (512) in a treatment plant (500).

Description

[0001] Description

[0002] title

[0003] Temperature treatment stage and method for treating a fluid and

[0004] Treatment system for treating workpieces

[0005] State of the art

[0006] The invention relates to a temperature treatment stage for treating a fluid, in particular for thermally treating a treatment fluid of a treatment device for treating workpieces, a treatment system in which a workpiece to be treated can be treated with a treatment fluid in a treatment device, in particular a pretreatment system or dip-coating system, with a temperature treatment stage, and a method for thermally treating a treatment fluid of a treatment system.

[0007] Due to the increased use of heavy metal-free chemicals in pretreatment (VBH) and / or cathodic dip painting (KTL), particularly in the painting of vehicle bodies, microbiological contamination can occur in these VBH / KTL system components, which is associated with quality problems in the KTL painting process, especially in KTL.

[0008] The state of the art in VBH is to use disinfection processes such as UV irradiation, catalytic processes, electro-pulse processes and ultrasound treatment, also in combination with UV irradiation, or to carry out chemical disinfection of baths and connected units at specific intervals using, for example, hydrogen peroxide, chlorine dioxide or peracetic acid. The aim of the disinfection processes at these points is to prevent contaminants from being carried over into the KTL tank, where they can cause major damage and correspondingly high costs. In addition to the rinsing baths in VBH, increased microbiological contamination can also occur in the bath in which the workpiece receives a nanocoating, for example based on zirconium oxide and zirconium oxide with organic components, such as silane.

[0009] For health and environmental protection reasons, and to avoid the use of nickel and phosphate, these nanocoating systems are increasingly replacing the previous phosphating process, which, due to the temperature and pH values, has so far been free of microbial contamination problems. Currently, ultrasonic and electro-pulse processes have been used in nanocoating baths. Chemical disinfection with the chemicals described above is not possible because they are incompatible with the coating chemicals. A biocide can only be used if it is compatible with the bath chemistry.

[0010] In cathodic dip painting systems, it has so far only been common practice to add biocides for disinfection or germ reduction, either continuously or intermittently as the germ count increases. Due to strict legal requirements regarding the use of such chemicals, including the European Union's REACH (Registration, Evaluation, Authorisation and Restriction of Chemicals) regulation, the use of new biocides is becoming more difficult, with the risk that the microorganisms will adapt to the biocides, rendering them ineffective, and potentially leading to the overturning of the cathodic dip bath, for example, with a volume of between 100 and 500 m³. 3 , which must be disposed of at great expense.

[0011] Disclosure of the invention

[0012] An object of the invention is to provide a temperature treatment stage of a treatment plant which allows a simple and cost-effective treatment of a fluid in the treatment plant.

[0013] A further task is the creation of a treatment plant with such a temperature treatment stage.

[0014] A further object is to provide a method for treating a treatment fluid in such a treatment system. These objects are achieved by the features of the independent claims. Advantageous embodiments and advantages of the invention emerge from the further claims, the description, and the drawings.

[0015] The features listed individually in the patent claims can be combined with one another in a technologically meaningful manner and can be supplemented by explanatory facts from the description and by details from the figures, whereby further embodiments of the invention are shown.

[0016] According to one aspect of the invention, a temperature treatment stage for treating a fluid, in particular for thermally treating a treatment fluid of a treatment device for treating workpieces, is proposed, comprising at least one recuperation heat exchanger with a primary side and a secondary side, which are intended to exchange heat with one another, and a heating stage for heating the treatment fluid to a target temperature. A flow circuit for the treatment fluid comprises, in its flow direction, the primary side of the recuperation heat exchanger, the heating stage, and the secondary side of the recuperation heat exchanger. A temperature maintenance unit is arranged in the flow circuit downstream of the heating stage and upstream of the secondary side of the recuperation heat exchanger, in which the treatment fluid has a predetermined residence time at the target temperature.

[0017] The proposed temperature treatment stage offers a beneficial solution for biocide-free disinfection or germ reduction of treatment equipment, such as spray systems or immersion baths, particularly nanocoating baths in a VBH system and / or a KTL system. Further advantageous applications are possible in the general pretreatment of metal parts such as screws, sheet metal, molded parts, workpieces, etc., as well as in electroplating, powder coating, anodizing, aluminum, plastic, and automotive painting systems, where metal and plastic parts are pretreated and subsequently coated. The treatment fluid can be used in an immersion bath or sprayed on in a spray system.

[0018] Further advantageous applications can be found in the field of dip coating and the associated anolyte system. The temperature treatment stage enables the use of a process that is primarily used in food technology for disinfecting liquids, milk, juices, and beer before bottling: pasteurization or flash pasteurization (FSP). The goal here is to treat the liquids so that they are as germ-free as possible. One measure of pasteurization is the Pasteur Unit (PU), which must be determined for each medium—in this case, the treatment fluid.

[0019] The temperature treatment stage serves to heat the treatment fluid to a temperature required to kill germs and to maintain this temperature for a period of time required to kill germs.

[0020] The temperature treatment stage can be integrated into one of the existing fluid circuits of the treatment plant and can be flowed through by the treatment fluid.

[0021] Alternatively, the temperature treatment stage can have its own supply and return lines, through which treatment fluid can be drawn, for example, from a fluid tank in the treatment plant. The treatment fluid can then flow through the temperature treatment stage and then be returned to a fluid tank, optionally the same one. The points for withdrawal and return to the fluid tank can be positioned so that freshly returned treatment fluid is not immediately withdrawn, but first mixes with the tank contents. To this end, the positions can be arranged as far apart as possible, or the withdrawal point can be positioned upstream of the return point if there is flow in the tank. Ideally, a flow barrier, such as a weir, can be located between the two positions.The temperature treatment stage comprises at least one recuperation heat exchanger for heating the treatment fluid flowing into the temperature treatment stage while simultaneously recooling the treatment fluid flowing out of it after the temperature treatment. This can preferably be a plate heat exchanger operating in countercurrent. Advantageously, 50% to 95%, preferably approximately 80%, of the heat input for heating the treatment fluid to the temperature required for germ destruction can take place in the recuperation heat exchanger.

[0022] Furthermore, the temperature treatment stage comprises a heating stage for completely heating the treatment fluid to the required temperature, in particular the predetermined target temperature, for germ killing, as well as a temperature holding unit in which the treatment fluid remains at a virtually constant temperature, in particular the predetermined target temperature, for the required duration for germ killing.

[0023] In the heating stage, thermal energy must be supplied to the treatment fluid to heat it to the temperature required to kill germs. For this purpose, the heating stage preferably comprises a heat exchanger, such as a plate heat exchanger, which is supplied with a heating medium. The heating medium, preferably hot water, can either be drawn from a central supply network or provided directly at the temperature treatment stage, for example, by a flow heater, a heat pump, or a boiler.

[0024] Alternatively, the heating stage can also be implemented in the form of direct heating of the treatment fluid without additional heating medium, for example by the treatment fluid itself passing through a continuous flow heater, where it is heated, for example, by electrical heating.

[0025] The coupling device for coupling the temperature treatment stage to the treatment device and / or a storage container can be, for example, a suitable connection, a valve, a pipeline, or the like. While in the food industry, the product medium flows in only one direction from product production to product filling, and complete disinfection is intended to be achieved, in the treatment plant, flash heating serves as a germ sink for the connected treatment devices in order to reduce the germ count to the lowest possible level. In an exemplary VBH / KTL system, the treatment fluid typically circulates in a closed circuit.

[0026] The process is advantageously completely chemical-free. The pasteurization temperature and / or residence time depend on the medium being treated and can easily be tested in preliminary trials.

[0027] Tests with a nanocoating bath and a cathodic dip bath have shown that a significant reduction in germs can be seen when temperatures reach 60°C.

[0028] Except for a pump, the temperature treatment stage can operate without moving parts and is therefore particularly low-maintenance.

[0029] One advantage of the proposed temperature treatment stage is a significant reduction in germs in a treatment system, e.g., a VBH and / or a KTL system. The temperature treatment stage can be conveniently integrated into a treatment system as a germ sink. The flash heating can be fully automated and delivers reproducible disinfection results.

[0030] The temperature treatment stage can operate with low energy consumption through the use of heat exchangers. This results in a simple system design. The short-term heating can be carried out in a way that is gentle on the product.

[0031] According to an advantageous embodiment of the temperature treatment stage, the predetermined residence time in the temperature-maintaining unit can be set by a volume of the temperature-maintaining unit and / or a length of the temperature-maintaining unit and / or a flow rate through the temperature-maintaining unit and / or a flow resistance of the temperature-maintaining unit. The temperature-maintaining unit can advantageously be a container that can hold a sufficiently large quantity of treatment fluid. The temperature-maintaining unit can advantageously hold the treatment fluid heated to the temperature required to kill germs for the duration required to kill germs and in doing so prevent cooling of the treatment fluid. The aim is to ensure that the residence time of the treatment fluid is as uniform as possible. This means that the flow through the temperature-maintaining unit should be as uniform as possible without causing mixing of the fluid.Dead spaces with no significant flow velocity or with internally circulating vortices should be avoided wherever possible. In the case of treatment fluids such as dip coatings, which contain components of different densities, it is advantageous to prevent the settling (sedimentation) of higher-density components at the bottom or on the inner walls of the temperature maintenance unit, as this could lead to contamination and ultimately blockage of the section.

[0032] According to an advantageous embodiment of the temperature treatment stage, the temperature-maintaining unit can comprise a hollow body, in particular a tubular one. In particular, at least one cross-sectional widening can be arranged inside the temperature-maintaining unit at its inlet into the hollow body. Alternatively or additionally, a cross-sectional tapering can be arranged inside the temperature-maintaining unit at its outlet from the hollow body.

[0033] A basic form of the temperature maintenance unit can be a vertically arranged, cylindrical container in the form of a hollow body. The average flow velocity of the treatment fluid (relative to the cross-section) can, for example, be in the range of 0.005 to 0.05 m / s, preferably in the range of 0.01 to 0.02 m / s. The diameter of the hollow body can be dimensioned such that an average flow velocity is established at the intended volume flow of the treatment fluid.

[0034] The treatment fluid can advantageously flow through the hollow body from top to bottom in the direction of gravity. At the upper end, at the treatment fluid inlet, the hollow body can comprise a multi-stage, preferably two-stage, cross-sectional expansion from the diameter of the supply line to the diameter of the cylindrical hollow body. At the treatment fluid outlet, the hollow body can comprise a cross-sectional taper from the diameter of the cylindrical hollow body to the diameter of the treatment fluid outlet. The hollow body can preferably be thermally insulated.

[0035] The first stage of cross-sectional expansion can, for example, be designed as a simple concentric pipe reducer. The first stage can expand the cross-sectional area to at least approximately one-tenth of the cross-sectional area of ​​the cylindrical vessel section.

[0036] The second stage can serve to further expand the cross-sectional area up to the full diameter of the cylindrical container section. The opening angle of the second stage of the expansion can preferably be in the range of 10 degrees to 45 degrees. In particular, an opening angle of approximately 30 degrees offers a good compromise between uniform flow expansion and a still moderate structural length of the, for example, conical section. In the region of the second expansion, the hollow body can preferably have internals for uniformly distributing the fluid flow across the container cross-sectional area. These internals cause flow expansion in the region of the, for example, conical cross-sectional expansion at the container inlet. The combination of the number, size, and shape of the internals influences the flow expansion.

[0037] Preferably, these fittings are conically shaped. The shape can correspond to the surface of a truncated cone. For example, straight, concentric pipe reducers according to DIN EN 10253-3 can be used.

[0038] Preferably, two differently sized, nested internals can be used to distribute the fluid flow from a vertical supply line evenly over the expanded cross-section of the cylindrical hollow body.

[0039] For this purpose, the internals can preferably be dimensioned and arranged such that the pipeline cross-section is divided into three surface areas, consisting of an inner circular area, a central annular area, and an outer annular area. Before expansion, the circular area can, for example, comprise a maximum of one-third of the total cross-sectional area, preferably 15% to 25% of the total cross-sectional area. The central annular area can comprise approximately one-third of the total cross-sectional area. The outer annular area can comprise at least one-third of the total cross-sectional area, preferably 5% to 42% of the total cross-sectional area.

[0040] After expansion, in the cylindrical part of the hollow body, all surface portions can preferably each comprise one third of the total cross-sectional area.

[0041] The length or height of the hollow body can be dimensioned such that the residence time of the treatment fluid in the hollow body, based on the given flow velocity, corresponds to the duration required to kill germs. The length of the cylindrical part can preferably be in the range of 1 m to 5 m, ideally in the range of 1.5 m to 2.5 m.

[0042] The cross-sectional taper at the lower end may have an opening angle of less than 45 degrees, preferably not more than 30 degrees, in order to avoid the deposition of sediments on the inclined surface.

[0043] The hollow body can preferably be thermally insulated.

[0044] The hollow body may preferably have a vent valve at the upper end.

[0045] The hollow body can be opened in the area of ​​cross-sectional changes, preferably for cleaning purposes. For example, the conical elements can be attached to the cylindrical part with a screw or clamp connection and can be removed for cleaning purposes.

[0046] To limit the vertical height, the temperature maintenance unit can consist of several containers arranged side by side, through which the fluid flows one after the other. For example, instead of a 4 m high container, two 2 m high containers can be provided, through which the fluid flows one after the other. To enable operation of the temperature treatment stage with different volume flows of the treatment fluid while maintaining a constant residence time, the temperature maintenance unit can comprise several hollow bodies through which the fluid flows in parallel. For example, with a high volume flow, the fluid can flow through two hollow bodies in parallel, while with a volume flow half as high, only one of the two hollow bodies flows through, leaving the second unused.

[0047] The flow through the hollow body in the direction of gravity, especially in conjunction with the conical taper of the cross-section at the lower end, prevents higher-density particles from settling at the bottom, even at very low flow velocities. Particles that sink due to their density are thus still carried away with the fluid flow through the outlet opening.

[0048] According to an advantageous embodiment of the temperature treatment stage, at least one flow-through insert, in particular at least one concentric tube, can be arranged inside the temperature-maintaining unit. The insert allows for a uniform distribution of the treatment fluid in the hollow body.

[0049] According to an advantageous embodiment of the temperature treatment stage, the at least one cross-sectional expansion can have at least one device for flow expansion, in particular a conical device, within its interior. In particular, the at least one flow-through insert body and the at least one flow expansion device can adjoin one another. These inserts can advantageously cause flow expansion in the region of the conical cross-sectional expansion at the hollow body inlet. The combination of the number, size, and shape of the inserts can advantageously influence the flow expansion.

[0050] According to an advantageous embodiment of the temperature treatment stage, the temperature maintenance unit can have a cavity at its inlet, particularly upstream of the flow expansion device, which is filled with air during normal operation. In particular, the cavity can have a compressed air connection. A metabolic product escaping from the treatment fluid can accumulate in the cavity and be removed for a possible determination of a microbial count. The cavity can preferably be positioned at a high point of the fluid flow system, within the temperature treatment stage, for example, at the outlet of the recuperation heat exchanger or at the inlet of the temperature maintenance unit.Preferably, the cavity can be arranged above the largest possible liquid reservoir and have the largest possible phase interface between the treatment fluid and the gas phase, as this allows a particularly high concentration of metabolic products in the gas phase. Therefore, a location at the inlet of the treatment fluid into the hollow body of the temperature maintenance unit can be advantageous.

[0051] The cavity can either be permanently filled with air or the treatment fluid can be displaced from it for the measurement by introducing compressed air.

[0052] According to an advantageous embodiment of the temperature treatment stage, a measuring device for determining a germ count of the treatment fluid can be arranged on the temperature maintenance unit.

[0053] According to an advantageous embodiment of the temperature treatment stage, the measuring device can be arranged at the inlet of the temperature maintenance unit or at the outlet of the recuperation heat exchanger. In particular, the measuring device can be fluidically coupled to a cavity of the temperature maintenance unit via a sampling line.

[0054] For the quantitative determination of the bacterial count, particularly in electrocoating, a measurement method can advantageously be used that is based on measuring the concentration of a metabolite of the bacteria that is soluble in the treatment fluid in the gas phase above the fluid. This metabolite is a component that is gaseous at room temperature, for example, carbon dioxide. To improve the accuracy (sensitivity) of the measurement, the solubility of the metabolite in the fluid can be reduced, at least locally, so that it accumulates in the gas phase to a greater extent, more rapidly, and / or to a higher equilibrium concentration.

[0055] To reduce the solubility of the metabolite, a shift in the pH value or an increase in temperature can be used. In the case of the metabolite carbon dioxide, this is an acidic gas that is highly soluble in alkaline solution but almost insoluble in acidic solution. In this case, the solubility can be reduced by adding an acid to the treatment fluid. Preferably, an acid that is already a component of the treatment fluid can be used. In the case of electrocoating for cathodic dip painting, for example, the acid produced at the anode can be added. This is usually removed from the system via an anolyte circuit in which the anodes are arranged in dialysis cells and separated from the dip paint by a membrane.A circulating fluid, the anolyte, flows through the dialysis cells. This fluid absorbs the acid, removes it from the treatment tank, and is continuously recycled. Due to its low pH, the anolyte itself or the recycled, particularly concentrated, acid can be added locally to lower the pH. Alternatively, the addition of an acid that is already used to adjust the bath pH as needed, such as acetic acid, can be considered. The acid can preferably be added to the treatment fluid (lacquer) directly below the point where the concentration is measured in the gas phase.

[0056] Alternatively or additionally, the effect of a reduction in solubility with increasing temperature can be utilized. This is particularly advantageous if a local increase in the temperature of the treatment fluid is already planned, such as in the case of short-term heating to kill germs in a temperature treatment stage. In this case, the measurement can preferably be taken immediately after the fluid has been heated, for example, after the recuperation heat exchanger or after the heater in the temperature treatment stage.

[0057] Instead of immersing a movable measuring bell into the treatment fluid, the measurement can preferably take place within the closed fluid flow system of the treatment plant or the temperature treatment stage. For this purpose, an air-filled cavity can be provided above the treatment fluid in the fluid flow system, in which the metabolite escaping from the treatment fluid collects. To measure the microbial count, gas can be extracted from the cavity via a measuring circuit and passed through a gas analysis unit, where the concentration of the metabolite is measured. At the same time, either the sample gas (after the measurement) or an equivalent amount of another gas, such as air or nitrogen, can be fed back into the cavity.

[0058] The absolute value or the temporal progression of the concentration of the metabolite in the gas phase can be used as a quantitative indicator of microbial contamination. For example, air introduced into the cavity at the beginning of a measurement can serve as a reference or baseline, while the rate of the subsequently recorded increase in concentration can be used as a measure of the concentration of microbes in the treatment fluid.

[0059] To increase sensitivity and / or shorten measurement time, the expulsion of the gaseous metabolite from the treatment fluid below the cavity can be further enhanced. For this purpose, it may be advantageous to introduce sample gas returned from the measurement circuit into the fluid below the cavity in the direction of gravity. The gas bubbles rising into the cavity enlarge the phase interface for mass transfer and can absorb metabolite from the treatment fluid during their ascent. Alternatively or additionally, the rise of tiny gas bubbles from the fluid into the cavity can be promoted, for example, with the aid of ultrasound.

[0060] Optionally, it can be provided that the cavity can be automatically rinsed with a cleaning fluid during operation of the temperature treatment stage. A fluid that is a component of the treatment fluid, such as demineralized water, an organic solvent, or preferably an ultrafiltrate of the treatment fluid, can be considered as the cleaning fluid. The quantitative value for microbial contamination determined by the measurement can optionally be used to regulate the operation of the temperature treatment stage. For example, the throughput to be treated can be regulated in a continuous operation mode as a continuous microbial sink of treatment fluid so that a certain level of microbial contamination is not exceeded during the treatment process.Alternatively or additionally, the temperature treatment stage can be switched off if the contamination falls below a lower limit and / or switched to a complete disinfection mode if the contamination exceeds an upper limit.

[0061] Optionally, a gas analysis unit can be switchably supplied with sample gas from several such measuring points (cavities) in order to quantitatively determine the contamination at several positions in the treatment process.

[0062] According to an advantageous embodiment of the temperature treatment stage, the heating stage can be fluidically coupled to a primary side of a heat pump, which provides at least one heating circuit for the heating stage.

[0063] The heat flows to be supplied to the heating stage and discharged to an optional cooling stage can preferably be coupled. In particular, a heat pump can be provided to supply the heat flow discharged from the cooling stage to the heating stage, where it can heat the treatment fluid.

[0064] The main advantages of this coupling are energy savings, which result from the fact that no heat and cold flows need to be supplied or removed, but only electrical energy is required to operate the heat pump. The electrical energy required can be reduced to a fraction of that required to generate the cold and heat flows using chillers and electric boilers. Furthermore, external supply lines for the heating and cooling medium can be eliminated. This can result in significant cost savings if there are no connections to these media in the immediate vicinity of the installation site. Furthermore, the installation effort for a temperature treatment stage can be reduced, since no additional media connections are required besides the connection for the treatment fluid.According to an advantageous embodiment of the temperature treatment stage, a secondary side of the heat pump can be coupled to a cooling stage for the treatment fluid arranged in the flow circuit downstream of the secondary side of the recuperation heat exchanger.

[0065] In the optional cooling stage, thermal energy is extracted from the treatment fluid to cool it to the required process temperature. For this purpose, the cooling stage can preferably comprise a heat exchanger, for example, a plate heat exchanger, which is supplied with a cooling medium. The cooling medium, preferably cold water, can be obtained from a central supply network, for example, or provided directly at the temperature treatment stage, for example, by a heat pump.

[0066] According to an advantageous embodiment of the temperature treatment stage, the heating stage can be formed by a heat pump.

[0067] In this case, the heat pump can serve directly as a heating stage and optionally as a cooling stage. This eliminates the need for a separate heating stage or heating medium circuit. Instead, heat transfer takes place directly between the heat source in the heat pump and the treatment fluid. The treatment fluid can flow through a heat exchanger within the heat pump, where it absorbs heat, for example, from the condensation of a working fluid.

[0068] Likewise, no separate cooling stage or cooling medium circuit is required. Instead, a direct heat transfer takes place between the treatment fluid and the heat sink in the heat pump. The treatment fluid can flow through a heat exchanger within the heat pump, where it releases heat, for example, for the evaporation of a working fluid.

[0069] The heating output of the heat pump can be regulated based on a temperature measurement in the treatment fluid so that the temperature of the treatment medium required to kill germs is reached or not undercut. Due to its design, the available cooling output of the heat pump is somewhat lower than the heat output, so that the treatment fluid can generally only be cooled approximately, but not completely, back to its original temperature during the treatment process. According to an advantageous embodiment of the temperature treatment stage, at least one treatment device for treating, in particular for cleaning, the treatment fluid can be provided in the flow circuit. In particular, the at least one treatment device can have at least one filter stage.

[0070] Alternatively or additionally, at least one

[0071] A flushing connection must be provided. Connections for flushing the

[0072] The temperature treatment stage or individual components such as heat exchangers or temperature maintenance units can advantageously be provided with a cleaning fluid for cleaning purposes. The cleaning fluid is preferably a fluid that is a component of the treatment fluid. For example, in the case of the temperature treatment stage for electrocoating, an (ultra)filtrate of the coating, demineralized water, organic acid, or the electrolyte from the electrode circuit can be used.

[0073] According to a further aspect of the invention, a treatment system is proposed in which a workpiece to be treated can be treated with a treatment fluid in a treatment device, in particular a pretreatment system or dip-coating system, having a temperature treatment stage for thermally treating the treatment fluid. The temperature treatment stage comprises at least one recuperation heat exchanger with a primary side and a secondary side, which are intended to exchange heat with one another, and a heating stage for heating the treatment fluid to a desired temperature. A flow circuit for the treatment fluid comprises, in its flow direction, the treatment device, the primary side of the recuperation heat exchanger, the heating stage, and the secondary side of the recuperation heat exchanger.A temperature maintenance unit is arranged in the flow circuit downstream of the heating stage and upstream of the secondary side of the recuperation heat exchanger, in which the treatment fluid has a predetermined residence time at the target temperature. The proposed treatment system for treating a workpiece with a treatment fluid comprises at least one treatment device with one or more fluid circuits in which the treatment fluid is moved for the treatment process itself or for the purpose of fluid preparation, for example, filtration or cooling, and / or a fluid tank in which the treatment fluid is stored or in which the treatment process can take place by inserting the workpieces, for example, an immersion bath. The treatment system further comprises a temperature treatment stage for briefly heating the treatment fluid to kill germs contained therein.

[0074] Optionally, a cooling stage can be present, which can optionally be part of the temperature treatment stage.

[0075] In contrast to the state of the art, the cooling stage is not mandatory, nor does it necessarily have to be part of the temperature treatment stage. For example, treatment systems for electrocoating are usually already equipped with a cooling stage, so ideally, an additional cooling stage in the temperature treatment stage can be omitted. If a temperature treatment stage is used for treatment fluids that must be heated anyway for the treatment process, a cooling stage may even be omitted entirely.

[0076] Furthermore, a measuring device for quantifying the number of germs in the treatment fluid can optionally be present.

[0077] The temperature treatment stage offers a beneficial solution for biocide-free disinfection or germ reduction of treatment equipment, such as spray systems or immersion baths, especially nanocoating baths in a VBH system and / or a KTL system. Further advantageous applications are possible in the general pretreatment of metal parts such as screws, sheet metal, molded parts, workpieces, etc., as well as in electroplating, powder coating, anodizing, aluminum, plastic, and automotive painting systems, where metal and plastic parts are pretreated and subsequently coated. The treatment fluid can be used in an immersion bath or sprayed on in a spray system. Further advantageous applications can be found in the field of dip painting and the connected anolyte system.

[0078] The temperature treatment stage enables the use of a process that is primarily used in food technology for disinfecting liquids, such as milk, juices, and beer, prior to bottling: pasteurization or flash heating (FHT). The goal here is to treat the liquids to make them as germ-free as possible. One measure of pasteurization is the Pasteur Unit (PTU), which must be determined for each medium—here, the treatment fluid.

[0079] The temperature treatment stage serves to heat the treatment fluid to a temperature required to kill germs and to maintain this temperature for a period of time required to kill germs.

[0080] The temperature treatment stage can be integrated into one of the existing fluid circuits of the treatment plant and can be flowed through by the treatment fluid.

[0081] Alternatively, the temperature treatment stage can have its own supply and return lines, through which treatment fluid can be drawn, for example, from a fluid tank in the treatment plant. The treatment fluid can then flow through the temperature treatment stage and then be returned to a fluid tank, optionally the same one. The points for withdrawal and return to the fluid tank can be positioned so that freshly returned treatment fluid is not immediately withdrawn, but first mixes with the tank contents. To this end, the positions can be arranged as far apart as possible, or the withdrawal point can be positioned upstream of the return point if there is flow in the tank. Ideally, a flow barrier, such as a weir, can be located between the two positions.

[0082] Advantageously, in the recuperation heat exchanger, the treatment fluid on the primary side can be heated by the fluid on the secondary side. According to an advantageous embodiment of the treatment system, a closed flow circuit can be formed in which the treatment fluid is conducted from the treatment device to the temperature treatment stage and back to the treatment device. This ensures that the treatment fluid can undergo thermal treatment to kill germs.

[0083] According to an advantageous embodiment of the treatment plant, a cooling stage can be arranged downstream of the heating stage in the flow circuit. In particular, the cooling stage can comprise a heat exchanger that is fluidically coupled to a separate cooling circuit.

[0084] In the cooling stage, thermal energy is extracted from the treatment fluid to cool it to the required process temperature. For this purpose, the cooling stage can preferably comprise a heat exchanger, for example, a plate heat exchanger, which is supplied with a cooling medium. The cooling medium, preferably cold water, can be obtained, for example, from a central supply network or provided directly at the temperature treatment stage, for example, by a heat pump.

[0085] According to an advantageous embodiment of the treatment system, a separate cooling stage can be provided on the treatment device outside the flow circuit. In particular, the cooling stage can comprise a heat exchanger that is fluidically coupled to a separate cooling circuit. For example, treatment systems for electrocoating are usually already equipped with a cooling stage so that it can be used to cool the treatment fluid. The cooling stage can preferably comprise a heat exchanger, for example, a plate heat exchanger, which is supplied with a cooling medium. The cooling medium, preferably cold water, can be obtained, for example, from a central supply network.

[0086] According to an advantageous embodiment of the treatment system, the heating stage can be heated by a heat pump. The heat flows to be supplied to the heating stage and discharged to an optional cooling stage can preferably be coupled. In particular, a heat pump can be provided to supply the heat flow discharged from the cooling stage to the heating stage and achieve heating of the treatment fluid there.

[0087] The main advantages of this coupling are energy savings, which result from the fact that no heat or cold flows need to be supplied or removed; instead, only electrical energy is required to operate the heat pump. Furthermore, external supply lines for the heating and cooling media are no longer required. This can result in significant cost savings if connections to these media are not available in the immediate vicinity of the installation site. Furthermore, the installation effort for a temperature treatment stage can be reduced, since no additional media connections are required besides the connection for the treatment fluid.

[0088] Alternatively, the heating stage can be provided by a heat pump.

[0089] In this case, the heat pump can serve directly as a heating stage and optionally as a cooling stage. This eliminates the need for a separate heating stage or heating medium circuit. Instead, heat transfer takes place directly between the heat source in the heat pump and the treatment fluid. The treatment fluid can flow through a heat exchanger within the heat pump, where it absorbs heat, for example, from the condensation of a working fluid.

[0090] Likewise, no separate cooling stage or cooling medium circuit is required. Instead, a direct heat transfer takes place between the treatment fluid and the heat sink in the heat pump. The treatment fluid can flow through a heat exchanger within the heat pump, where it releases heat, for example, for the evaporation of a working fluid.

[0091] According to an advantageous embodiment of the treatment system, a measuring device for determining the bacterial count of the treatment fluid can be arranged at an inlet of the temperature-maintaining unit or at an outlet of the recuperation heat exchanger. For the quantitative determination of the bacterial count, in particular of electrocoating, a measuring method can advantageously be used that is based on measuring the concentration of a metabolic product of the germs that is soluble in the treatment fluid in the gas phase above the fluid. The metabolic product is a component that is gaseous at room temperature, for example carbon dioxide. To improve the measurement accuracy (sensitivity), the solubility of the metabolic product in the fluid can be reduced, at least locally, so that it accumulates in the gas phase to a greater extent, more quickly, and / or to a higher equilibrium concentration.

[0092] To reduce the solubility of the metabolite, a shift in the pH value or an increase in temperature can be used.

[0093] Instead of immersing a movable measuring bell into the treatment fluid, the measurement can preferably take place within the closed fluid flow system of the treatment plant or the temperature treatment stage. For this purpose, an air-filled cavity can be provided in the fluid flow system above the treatment fluid, in which the metabolic product escaping from the treatment fluid collects.

[0094] According to an advantageous embodiment of the treatment system, the treatment device can comprise one or more fluid circuits and / or a storage container, in particular an immersion tank, particularly as a pretreatment tank or as an immersion paint tank. The treatment fluid can be moved within the one or more fluid circuits for the treatment process itself or for the purpose of fluid conditioning, for example, filtration or cooling. The treatment fluid can be stored in the storage container, for example, a fluid tank, or the treatment process can take place therein by introducing the workpieces, for example, an immersion bath.

[0095] This advantageously results in a cost-effective design of a treatment system as a modular, self-contained system with minimal installation effort. The treatment system is highly energy efficient and offers simplified cleaning options. The measurement method for quantifying microbial contamination eliminates direct contact between the measuring sensor and the treatment fluid and does not require access to the bath surface of the treatment facility. The measuring device contains no moving parts and utilizes the heating of the treatment fluid to achieve increased sensitivity.

[0096] According to a further aspect of the invention, a method for the thermal treatment of a treatment fluid in a treatment plant with a temperature treatment stage is proposed. According to the invention, the treatment fluid is heated to a target temperature in a flow circuit by means of a recuperation heat exchanger with a primary side and a secondary side, which are intended to exchange heat with each other, and a heating stage. The treatment fluid is maintained at the target temperature for a predetermined residence time by means of a temperature maintenance unit arranged in the flow circuit downstream of the heating stage and upstream of the secondary side of the recuperation heat exchanger.

[0097] Two different operating modes can be used for the thermal treatment of the treatment fluid according to the proposed process. One option is continuous operation as a continuous germ sink. Treatment fluid is continuously withdrawn from the treatment process, passed through the temperature treatment stage for disinfection, and returned to the treatment process. The disinfected treatment fluid is thus continuously mixed with the contaminated treatment fluid. At the same time, germs are continuously killed in the temperature treatment stage, preventing uncontrolled proliferation of the germs. Continuous disinfection can take place during ongoing operation of the treatment plant.

[0098] Alternatively, complete disinfection is possible. The entire treatment fluid passes successively through the temperature treatment stage, with the disinfected fluid being collected in a separate tank to prevent it from mixing with contaminated fluid. Electrocoating systems usually have additional tanks large enough to hold the entire treatment fluid, as these are needed for temporary emptying of the process tank for cleaning or maintenance purposes. Complete disinfection takes place as needed, for example, at set intervals, after a set number of painting cycles, or when a certain germ concentration, which is determined by measurement, is exceeded. Complete disinfection cannot usually take place while the treatment system is in operation, but rather during downtimes, for example, at night or on weekends.

[0099] To maintain the most consistent quality of the treatment fluid possible, continuous operation as a continuous germ sink is preferable. Complete disinfection can be performed as a supplement if necessary.

[0100] According to an advantageous embodiment of the process, the treatment fluid in the flow circuit downstream of the recuperation heat exchanger can be cooled by means of a cooling stage. In the cooling stage, thermal energy is extracted from the treatment fluid to cool it to the required process temperature.

[0101] According to an advantageous embodiment of the method, the treatment fluid can be cooled by means of a separate cooling stage fluidically coupled to the treatment device. In the cooling stage, thermal energy is extracted from the treatment fluid to cool it to the required process temperature.

[0102] According to an advantageous embodiment of the method, the treatment fluid on the primary side of the recuperation heat exchanger can be preheated by heated treatment fluid on the secondary side of the recuperation heat exchanger. This saves energy both for heating the treatment fluid and for cooling the treatment fluid heated during the thermal treatment. Drawing

[0103] Further advantages will become apparent from the following description of the drawings. The drawings illustrate exemplary embodiments of the invention. The drawings, the description, and the claims contain numerous features in combination. Those skilled in the art will also expediently consider the features individually and combine them into useful further combinations.

[0104] Examples include:

[0105] Fig. 1 is a schematic representation of a treatment system according to an embodiment of the invention, in which a workpiece to be treated can be treated with a treatment fluid in a treatment device, with a temperature treatment stage for thermally treating the treatment fluid;

[0106] Fig. 2 is a schematic representation of a treatment plant according to a further embodiment of the invention, wherein the heating stage and the cooling stage are coupled to a heat pump;

[0107] Fig. 3 is a schematic representation of a treatment plant according to a further embodiment of the invention with a heat pump as heating stage and cooling stage;

[0108] Fig. 4 is a schematic representation of a temperature holding unit of the temperature treatment stage according to an embodiment of the invention;

[0109] Fig. 5 is a schematic representation of a temperature holding unit of the temperature treatment stage according to a further embodiment of the invention with a measuring device for determining a germ count of the treatment fluid.

[0110] Embodiments of the invention

[0111] In the figures, similar or similarly functioning components are numbered with the same reference numerals. The figures show only examples and are not to be understood as limiting. Before the invention is described in detail, it should be pointed out that it is not limited to the respective components of the device or the respective method steps, since these components and methods can vary. The terms used here are intended only to describe particular embodiments and are not used in a limiting manner. Furthermore, when the singular or indefinite article is used in the description or in the claims, this also refers to the plural of these elements, unless the overall context clearly indicates otherwise.

[0112] The directional terminology used below, including terms such as "left," "right," "top," "bottom," "before," "behind," "after," and the like, is intended solely to enhance understanding of the figures and is in no way intended to limit the scope of the invention. The components and elements depicted, as well as their design and use, may vary according to the considerations of a person skilled in the art and may be adapted to specific applications.

[0113] Figure 1 shows a schematic representation of a treatment system 500 according to an embodiment of the invention, in which a workpiece 10 to be treated can be treated in a treatment device 510 with a treatment fluid 512, with a temperature treatment stage 100 for thermally treating the treatment fluid 512.

[0114] The treatment system 500 can, in particular, be a pretreatment system or a dip-coating system. The treatment device 510 can, for this purpose, comprise one or more fluid circuits and / or a storage tank, in particular an immersion tank, in particular as a pretreatment tank or as an immersion tank.

[0115] The temperature treatment stage 100 comprises a recuperation heat exchanger 400 with a primary side 402 and a secondary side 404, which are intended to exchange heat with each other, and a heating stage 300 for heating the treatment fluid 512 to a target temperature. The temperature treatment stage 100 further comprises, in the flow circuit 700, downstream of the heating stage 300 and upstream of the secondary side 404 of the recuperation heat exchanger 400, a temperature maintenance unit 310 in which the treatment fluid 512 has a predetermined residence time at the target temperature.

[0116] The flow circuit 700 for the treatment fluid 512 thus comprises, in its flow direction 750, the treatment device 510, the primary side 402 of the recuperation heat exchanger 400, the heating stage 300, and the secondary side 404 of the recuperation heat exchanger 400. In the flow circuit 700, the temperature maintenance unit 310 is arranged downstream of the heating stage 300 and upstream of the secondary side 404 of the recuperation heat exchanger 400. The temperature maintenance unit 310, in which the treatment fluid 512 has a predetermined residence time at the target temperature, is arranged. Thus, a closed flow circuit 700 is formed, in which the treatment fluid 512 is guided from the treatment device 510 to the temperature treatment stage 100 and back to the treatment device 510.

[0117] The treatment fluid 512 can be preheated in the recuperation heat exchanger 400 on the primary side 402 by the fluid on the secondary side 404.

[0118] The treatment fluid 512 flows in the flow circuit 700 in the flow direction 750 from the treatment device 510 via the pump 118 in the line section 702 into the primary side 402 of the heat exchanger 400. From there, the treatment fluid 512 flows via the line section 704 into the heat exchanger 301 of the heating stage 300, from there into the temperature maintenance unit 310 and via the line section 706 back to the secondary side 404 of the heat exchanger 400. From there, the treatment fluid 512 can flow back into the treatment device 510 via the line section 720.

[0119] The heating stage 300 has the heat exchanger 301, which is supplied via lines 302 and a pump 308 via a separate heating circuit 316, which is fed by the supply 306, and can thus heat the treatment fluid 512. The heating stage 300 has a supply 306 with a heating medium, wherein the heating medium can preferably be generated locally, for example, by an electric instantaneous water heater. Alternatively, the supply 306 can also consist of a connection to a hot water supply network and, if necessary, a hot water control group. In this exemplary embodiment, the cooling circuit 250 of the treatment device 510 has its own cooling stage 200, which can also be used by the temperature treatment stage 100 and whose output is sufficiently large to dissipate the heat input from the temperature treatment stage 100 into the treatment process in addition to the process heat to be dissipated.

[0120] The cooling stage 200 is thus located at the treatment device 510 outside the flow circuit 700. The cooling stage 200 has a heat exchanger 201, which is fluidically coupled to the cooling circuit 250 of the treatment device 510. The cooling circuit 250 has a line 202, which leads from the heat exchanger 201 to a cooling device 208 and back via a pump 206 to the heat exchanger 201. The treatment fluid 512 can flow via line 112 from the treatment device 510 into the heat exchanger 201 of the cooling stage 200 and, after being cooled, can be returned via line 122 to the treatment device 510.

[0121] According to the proposed method for thermally treating the treatment fluid 512 of the treatment plant 500 with the temperature treatment stage 100, the treatment fluid 512 is heated to a target temperature in the flow circuit 700 by means of the recuperation heat exchanger 400 and the heating stage 300, and is maintained at the target temperature for the predetermined residence time by means of the temperature maintenance unit 310.

[0122] The treatment fluid 512 is first preheated on the primary side 402 of the recuperation heat exchanger 400 by heated treatment fluid 512 on the secondary side 404 of the recuperation heat exchanger 400. 50% to 95%, preferably approximately 80%, of the heat input can be used to heat the treatment fluid 510 to the temperature required to kill germs. The treatment fluid 512 is then further heated in the heating stage 300 to a predetermined target temperature and then flows into the temperature maintenance unit 310. The predetermined residence time in the temperature maintenance unit 310 can be adjusted by a volume of the temperature maintenance unit 310 and / or a length of the temperature maintenance unit 310 and / or a flow rate through the temperature maintenance unit 310 and / or a flow resistance of the temperature maintenance unit 310.

[0123] After the thermal treatment, the treatment fluid 512 is cooled by means of the separate cooling stage 200 fluidically coupled to the treatment device 510.

[0124] At least one treatment device for treating, in particular for purifying, the treatment fluid 512 can also be provided in the flow circuit 700. In particular, the at least one treatment device can have at least one filter stage. Alternatively or additionally, at least one flushing connection can also be provided in the flow circuit 700.

[0125] Figure 2 shows a schematic representation of a treatment plant 500 according to a further embodiment of the invention, wherein the heating stage 300 and the cooling stage 200 are coupled to a heat pump 260.

[0126] The heating stage 300 is fluidically coupled to a primary side 262 of a heat pump 260, which provides a heating circuit 316 for the heating stage 300. In this way, the heat exchanger 301 on the secondary side can be supplied with heat from the heat pump 260 and transferred to the treatment fluid 512. The heating circuit 316 has lines 302, 304, a circulation pump 308, and a bypass 312, which can be controlled by a three-way mixing valve 314.

[0127] In the flow circuit 700, a cooling stage 200 is arranged downstream of the heating stage 300. The cooling stage 200 has a heat exchanger 201, which is fluidically coupled to a separate cooling circuit 250. As a result, the secondary side 264 of the heat pump 260 is coupled to the heat exchanger 201 of the cooling stage 200 via the cooling circuit 250. The cooling circuit 250 has lines 202, 204, a circulation pump 206, and a bypass 212, which can be controlled by a three-way mixing valve 214. The treatment fluid 512 can thus be cooled in the flow circuit 700 downstream of the recuperation heat exchanger 400 by means of the cooling stage 200.

[0128] The treatment fluid 512 flows in the flow circuit 700 in the flow direction 750 from the treatment device 510 via the pump 118 in the line section 702 into the primary side 402 of the heat exchanger 400. From there, the treatment fluid 512 flows via the line section 704 into the heat exchanger 301 of the heating stage 300, from there into the temperature maintenance unit 310 and via the line section 706 back to the secondary side 404 of the heat exchanger 400. From there, the treatment fluid 512 flows via the line section 708 into the heat exchanger 201 of the cooling stage 200. From there, the treatment fluid 512 can flow back into the treatment device 510 via the line section 720.

[0129] A heating medium in the heating circuit 316 is heated by the heat pump 260 and transfers this heat to the treatment fluid 512 in the heating stage 300. For this purpose, the heating medium passes through a heat exchanger 262 within the heat pump, where it absorbs heat, for example, through the condensation of a working medium. The heated heating medium then passes through the heating stage 300, where it transfers the heat to the treatment fluid 512. The heating circuit 316 has its own pump 308 for the heating medium and preferably a bypass 312 to the heating stage 300 with a control valve 314. The bypass 312 allows the flow of the heating medium to be divided, with one part flowing through the heating stage 300, while the remaining part instead passes through the short circuit between the flow 304 and return 302 of the heat pump 260. The bypass 312 can be used in particular to increase the temperature of the medium at the return line 302 to the heat pump 260.This can be useful, for example, for the duration of the start-up of the heat pump 260 until a stable temperature difference between the heat source and the heat sink has been established. A cooling medium in the cooling circuit 250 absorbs heat from the treatment fluid 512 in the cooling stage 200 and is then cooled by the heat pump 260. For this purpose, the cooling medium passes through a heat exchanger 264 within the heat pump 260, where heat is extracted from it, for example, for the evaporation of a working fluid. The heated heating medium then passes through the cooling stage 200, where it absorbs heat from the treatment fluid 512. The cooling circuit 250 has its own pump 206 for the cooling medium and preferably a bypass 212 to the cooling stage 200 with a control valve 214.The bypass 212 allows the flow of the cooling medium to be split, with one portion flowing through the cooling stage 200, while the remaining portion instead passes through the short circuit between the flow line 204 and the return line 202 of the heat pump 260. The bypass 212 can be used, in particular, to limit the temperature at the return line 202 to the heat pump.

[0130] Figure 3 shows a schematic representation of a treatment system 500 according to a further embodiment of the invention with a heat pump 270 as heating stage 300 and cooling stage 200. Both the heating stage 300 and the cooling stage 200 are formed by the heat pump 270.

[0131] In this case, the heat pump 270 serves directly to heat and cool the treatment fluid 512. The treatment fluid 512 is passed through the internal heat exchangers 272, 274 of the heat pump 270; separate heating stages 300 and cooling stages 200 are therefore not required.

[0132] To improve the start-up behavior of the treatment system 500, a bypass circuit is preferably provided, which enables circulation of the treatment fluid 512 between the flow line 706 and the return line 704 on the heat side of the heat pump 270. This allows a variable partial flow of the treatment fluid 512 from the flow line 706 to be mixed into the return line 704 or the entire flow of the treatment fluid 512 to be returned directly to the return line 704 until a stable temperature difference has been established between the heat source and the heat sink. The bypass circuit can be implemented, for example, by a three-way mixer valve 114 on the suction side of the pump 118 for the treatment fluid 512, which enables suction of a variable partial flow from the flow line 706 of the heat pump 270.Optionally, a further three-way mixer valve 118 can be provided, which allows bypassing of the recuperation heat exchanger 400 in the return line in order to initially dissipate no or less heat there for the duration of the start-up process.

[0133] The treatment fluid 512 flows in the flow circuit 700 in the flow direction 750 from the treatment device 510 via the pump 118 in the line section 702 into the primary side 402 of the heat exchanger 400. The heat exchanger 400 can also be bypassed via the mixing valve 116 in the line section 702 and the treatment fluid 512 can flow directly into the line section 704.

[0134] The treatment fluid 512 flows via line section 704 into the heat exchanger 272 of the heat pump 270, from there into the temperature maintenance unit 310 and to the mixing valve 114. From the temperature maintenance unit 310, the treatment fluid 512 flows via line section 708 to the secondary side 404 of the heat exchanger 400. From there, the treatment fluid 512 flows via line section 710 into the heat exchanger 274 of the heat pump 270. From there, the treatment fluid 512 can flow back into the treatment device 510 via line section 720.

[0135] Figure 4 shows a schematic representation of a temperature holding unit 310 of the temperature treatment stage 100 according to an embodiment of the invention.

[0136] The temperature-maintaining unit 310 comprises a hollow body 350, in particular a tubular one. A first conical cross-sectional widening 320 is arranged in front of a bend 342 inside the temperature-maintaining unit 310 at its inlet 318 into the hollow body 350. The bend 342 serves to reduce the overall height of the temperature-maintaining unit 310.

[0137] After the bend 342, a further conical cross-sectional widening 322 leads into the interior of the hollow body 350. A cross-sectional narrowing 324 is arranged inside the temperature-maintaining unit 310 at its outlet 319 from the hollow body 350. One or more flow-through installation bodies 325, which are designed, for example, as concentric tubes, are arranged inside the temperature-maintaining unit 310.

[0138] The second cross-sectional expansion 322 has one or more flow expansion devices 326 within its interior, in particular as conical devices 326, which serve to distribute the fluid flow evenly over the expanded cross-sectional area of ​​the interior of the temperature maintenance unit 310. The flow-through installation bodies 325 and the flow expansion devices 326 can be connected to one another.

[0139] A venting device 328 is arranged at the highest point on the manifold 342 to allow air pockets to escape from the temperature maintenance unit 310.

[0140] Figure 5 shows a schematic representation of a temperature holding unit 310 of the temperature treatment stage 100 according to a further embodiment of the invention with a measuring device for determining a germ count of the treatment fluid.

[0141] In this embodiment, the temperature maintenance unit 310 has a cavity 330 at its inlet 318, particularly upstream of the flow expansion device 326, which is filled with air during normal operation. As shown, the cavity 330 can have a compressed air connection 340, through which an air bubble can be generated by blowing in compressed air. Furthermore, the cavity 330 also has a venting device 328.

[0142] A measuring device 336 for determining the bacterial count of the treatment fluid 512 is also arranged on the temperature-maintaining unit 310. As shown in the exemplary embodiment, the measuring device 336 can be arranged at the inlet 318 of the temperature-maintaining unit 310. In particular, the measuring device 336 can be fluidically coupled to the cavity 330 of the temperature-maintaining unit 310 via a sampling line 334 and a shut-off valve 332. A return line 338 from the measuring device 336 can be coupled to the hollow body 350 of the temperature-maintaining unit 310, as schematically indicated in Figure 5. The measuring device 336 can, for example, comprise a gas pump for the sample gas and a gas analysis device, for example an infrared gas analyzer.Optionally, the measuring device 336 may comprise further components such as a gas cooler for condensing the moisture from the sample gas and / or devices for automated calibration.

[0143] The sample gas is returned to the cavity 330 via the return line 338. However, the return is advantageously not carried out directly into the cavity 330, but rather first into the interior of the hollow body 350 below, so that the returned sample gas rises through the treatment fluid 512 in the form of gas bubbles before collecting again in the cavity 330.

[0144] Alternatively, the measuring device 336 can also be arranged, for example, at the outlet of the recuperation heat exchanger 400.

[0145] Reference symbol

[0146] 10 Workpiece

[0147] 100 temperature treatment level

[0148] 112 Line

[0149] 114 Mixing valve

[0150] 116 Mixing valve

[0151] 118 Pump

[0152] 122 Line

[0153] 200 cooling level

[0154] 201 heat exchangers

[0155] 202 Line

[0156] 204 Line

[0157] 206 Pump

[0158] 208 Cooling device

[0159] 212 Bypass

[0160] 214 Mixing valve

[0161] 250 cooling circuit

[0162] 260 heat pump

[0163] 262 heat exchangers

[0164] 264 heat exchangers

[0165] 270 heat pump

[0166] 272 heat exchangers

[0167] 274 heat exchangers

[0168] 300 heat level

[0169] 301 heat exchanger

[0170] 302 line

[0171] 304 Line

[0172] 306 Supply

[0173] 308 Pump

[0174] 310 Temperature holding unit

[0175] 312 Bypass

[0176] 314 mixing valve

[0177] 316 Heating circuit

[0178] 318 Entrance

[0179] 319 Exit

[0180] 320 cross-sectional expansion

[0181] 322 Cross-sectional expansion

[0182] 324 Cross-sectional taper

[0183] 325 Installation body device for flow expansion

[0184] venting device

[0185] hollow space

[0186] shut-off valve

[0187] Sampling line

[0188] measuring device

[0189] Return line

[0190] Compressed air connection

[0191] Manifold

[0192] hollow body

[0193] Recuperation heat exchanger

[0194] Primary page

[0195] Secondary side

[0196] Treatment plant

[0197] Treatment facility

[0198] Treatment fluid

[0199] flow cycle

[0200] Line section

[0201] Line section

[0202] Line section

[0203] Line section

[0204] Line section

[0205] Line section

[0206] Line section

[0207] Flow direction

Claims

Claims 1. Temperature treatment stage (100) for treating a fluid, in particular for thermally treating a treatment fluid (512) of a treatment device (510) for treating workpieces, at least comprising a recuperation heat exchanger (400) with a primary side (402) and a secondary side (404), which are intended to be in heat exchange with one another, and a heating stage (300) for heating the treatment fluid (512) to a desired temperature, wherein a flow circuit (700) for the treatment fluid (512) comprises, in its flow direction (750), the primary side (402) of the recuperation heat exchanger (400), the heating stage (300) and the secondary side (404) of the recuperation heat exchanger (400), wherein in the flow circuit (700) downstream of the heating stage (300) and upstream of the secondary side (404) a temperature maintenance unit (310) is arranged in the recuperation heat exchanger (400),in which the treatment fluid (512) has a predetermined residence time at the desired temperature., 2. Temperature treatment stage according to claim 1, wherein the predetermined residence time in the temperature holding unit (310) is set by a volume of the temperature holding unit (310) and / or a length of the temperature holding unit (310) and / or a flow rate through the temperature holding unit (310) and / or a flow resistance of the temperature holding unit (310).

3. Temperature treatment stage according to claim 1 or 2, wherein the temperature-maintaining unit (310) comprises a hollow body (350), in particular a tubular one, in particular wherein at least one cross-sectional widening (320, 322) is arranged inside the temperature-maintaining unit (310) at its inlet (318) into the hollow body (350) and / or a cross-sectional taper (324) is arranged inside the temperature-maintaining unit (310) at its outlet (319) from the hollow body (350).

4. Temperature treatment stage according to claim 3, wherein in the interior of the temperature holding unit (310) at least one flow-through installation body (325), in particular at least one concentric tube, is arranged.

5. Temperature treatment stage according to claim 3 or 4, wherein the at least one cross-sectional widening (320, 322) has in its interior at least one device (326) for flow widening, in particular a conical device (326), in particular wherein the at least one flow-through installation body (325) and the at least one device (326) to expand the flow.

6. Temperature treatment stage according to one of the preceding claims, wherein the temperature maintenance unit (310) has a cavity (330) in the interior at its inlet (318), in particular in front of the device (326) for flow expansion, which is filled with air during normal operation, in particular wherein the cavity (330) has a compressed air connection (340).

7. Temperature treatment stage according to one of the preceding claims, wherein a measuring device (336) for determining a germ count of the treatment fluid (512) is arranged on the temperature maintenance unit (310).

8. Temperature treatment stage according to claim 7, wherein the measuring device (336) is arranged at the inlet (318) of the temperature maintenance unit (310) or at the outlet of the recuperation heat exchanger (400), in particular wherein the measuring device (336) is fluidically coupled to a cavity (330) of the temperature maintenance unit (310) via a sampling line (334).

9. Temperature treatment stage according to one of the preceding claims, wherein the heating stage (300) is fluidically coupled to a primary side (262) of a heat pump (260) which provides at least one heating circuit (316) for the heating stage (300).

10. Temperature treatment stage according to claim 9, wherein a secondary side (264) of the heat pump (260) is coupled to a cooling stage (200) for the treatment fluid (512) arranged in the flow circuit (700) downstream of the secondary side (404) of the recuperation heat exchanger (400).

11. Temperature treatment stage according to one of claims 1 to 8, wherein the heating stage (300) is formed by a heat pump (270).

12. Temperature treatment stage according to one of the preceding claims, wherein at least one processing device for processing, in particular for cleaning, the treatment fluid (512) is provided in the flow circuit (700), in particular wherein the at least one processing device has at least one filter stage and / or wherein at least one rinsing connection is provided in the flow circuit (700).

13. Treatment system (500) in which a workpiece (10) to be treated can be treated in a treatment device (510) with a treatment fluid (512), in particular pretreatment system or A sub-coating system, comprising a temperature treatment stage (100) for thermally treating the treatment fluid (512) according to one of the preceding claims, wherein the temperature treatment stage (100) comprises at least one recuperation heat exchanger (400) with a primary side (402) and a secondary side (404), which are intended to exchange heat with one another, and a heating stage (300) for heating the treatment fluid (512) to a desired temperature, wherein a flow circuit (700) for the treatment fluid (512) comprises, in its flow direction (750), the treatment device (510), the primary side (402) of the recuperation heat exchanger (400), the heating stage (300) and the secondary side (404) of the recuperation heat exchanger (400), wherein a temperature maintenance unit (310) is arranged in the flow circuit (700) downstream of the heating stage (300) and upstream of the secondary side (404) of the recuperation heat exchanger (400), in which the treatment fluid (512) has a predetermined residence time at the target temperature.

14. Treatment plant according to claim 13, wherein a closed flow circuit (700) is formed, in which the treatment fluid (512) is guided from the treatment device (510) to the temperature treatment stage (100) and back to the treatment device (510).

15. Treatment plant according to claim 13 or 14, wherein in the flow circuit (700) a cooling stage (200) is arranged downstream of the heating stage (300), in particular wherein the cooling stage (200) has a heat exchanger (201) which is fluidically coupled to a separate cooling circuit (250).

16. Treatment plant according to claim 13 or 14, wherein a separate cooling stage (200) is present on the treatment device (510) outside the flow circuit (700), in particular wherein the cooling stage (200) has a heat exchanger (201) which is fluidically coupled to a separate cooling circuit (250).

17. Treatment plant according to one of claims 13 to 16, wherein the heating stage (300) is heated by a heat pump (260), or wherein the heating stage (300) is formed by a heat pump (270).

18. Treatment plant according to one of claims 13 to 17, wherein a measuring device (336) for determining a germ count of the treatment fluid (512) is arranged at an inlet (318) of the temperature maintenance unit (310) or at an outlet of the recuperation heat exchanger (400).

19. Treatment plant according to one of claims 13 to 18, wherein the treatment device (510) comprises one or more fluid circuits and / or a storage container, in particular an immersion tank, in particular as a pretreatment tank or as an immersion paint tank.

20. A method for the thermal treatment of a treatment fluid (512) of a treatment plant (500) according to one of claims 13 to 19 with a temperature treatment stage (100) according to one of claims 1 to 13, characterized in that the treatment fluid (512) is heated to a desired temperature in a flow circuit (700) by means of a recuperation heat exchanger (400) with a primary side (402) and a secondary side (404), which are intended to exchange heat with one another, and a heating stage (300), and is held at the desired temperature for a predetermined residence time by means of a temperature maintenance unit (310) arranged in the flow circuit (700) downstream of the heating stage (300) and upstream of the secondary side (404) of the recuperation heat exchanger (400).

21. The method according to claim 20, wherein the treatment fluid (512) in the flow circuit (700) downstream of the recuperation heat exchanger (400) is cooled by means of a cooling stage (200).

22. The method according to claim 20 or 21, wherein the treatment fluid (512) is cooled by means of a separate cooling stage (200) fluidically coupled to the treatment device (510).

23. The method according to any one of claims 20 to 22, wherein the treatment fluid (512) on the primary side (402) of the recuperation heat exchanger (400) is preheated by heated treatment fluid (512) on the secondary side (404) of the recuperation heat exchanger (400).

Images