Plant for treating workpieces and operation of a plant

Abstract

A drying and / or curing installation (10) for drying and / or curing painted and / or coated and / or bonded workpieces has a processing chamber (18) for receiving workpieces (14) to be processed, which is connected to a process air line (40, 42, 44, 46, 50) for introducing and / or extracting process air into and / or out of the processing chamber, a heating apparatus (26-37) for heating process air to be introduced into the processing chamber (18), and a control device (55) for controlling the quantity of process air introduced into the processing chamber and / or extracted from the processing chamber and for controlling a heat output of the heating apparatus. The control device (55) is in this case configured such that it sets, controls and / or regulates the quantity of process air and the heat output in a manner dependent on one another or with regard to one another.

Description

[0001] The present invention relates to a workpiece processing system, in particular for drying and / or curing painted and / or coated and / or bonded workpieces, as well as to a method for operating a workpiece processing system, in particular for drying and / or curing painted and / or bonded workpieces. Specifically, the invention relates to the field of continuous dryers, continuous curing systems, chamber dryers, and chamber curing systems in which painted and / or bonded car bodies or car body parts can be dried and / or cured.

[0002] A drying and / or curing system of this type is known, for example, from WO 2010 / 122121 A2. This conventional drying and / or curing system has a process chamber with at least one zone for receiving workpieces to be processed, which zone is connected to a fresh air line for introducing fresh air into the process chamber and an exhaust air line for discharging exhaust air from the process chamber. To optimize the energy consumption of the drying and / or curing system, a fresh air and / or exhaust air volume control is also provided for controlling the amount of fresh air to be introduced into the process chamber and / or the amount of exhaust air to be discharged from the process chamber. The fresh air and / or exhaust air volume control is preferably carried out as a function of the number of workpieces currently supplied to the process chamber.

[0003] The drying and / or curing system disclosed in WO 2010 / 122121 A2 also has a thermal afterburner (TNV) to which exhaust air from the process chamber is fed for the purpose of thermal exhaust air purification and whose output clean air is fed to several recirculating air or fresh air recuperators in order to heat the recirculating air or fresh air to be introduced into the process chamber.

[0004] DE 10 2011 114 292 A1 describes a thermal oxidizer in which the combustion chamber temperature is not regulated to a fixed maximum value, but rather is controlled depending on the carbon monoxide content of the clean air emitted by the oxidizer. The resulting lower average combustion chamber temperatures are intended to save energy and protect the materials used there.

[0005] DE 10 2008 034 746 B4 discloses a device for drying painted vehicle bodies with a thermal afterburner, in which the pollutant concentration of organic solvents in the dryer is continuously measured. As the pollutant concentration increases, the fresh air supply to the process chamber is increased and the exhaust air discharge from the process chamber is reduced. The combustion chamber temperature is kept constant by reducing the fuel supply to the combustion chamber of the afterburner.

[0006] DE 10 2012 023 457 A1 describes a method and device for temperature control, in particular for drying objects. All control and regulation processes of the dryer are coordinated by a control unit, which controls valves, a process air blower, a fresh air blower, and a burner.

[0007] DE 20 2009 013 054 U1 discloses a system for controlling the interior temperature in a drying and / or painting booth for the refinishing of vehicles and vehicle parts. A temperature sensor non-contactingly detects the temperature on the surface of the object to be heated and / or dried, and a control and regulation device controls the fans and the heating device depending on the detected surface temperature of the object to be heated and / or dried.

[0008] GB 2 059 032 A discloses a device for drying painted vehicle bodies with an afterburner, in which the circulating process air quantity and the heating power of the afterburner are controlled as a function of the measured temperature in the drying chamber.

[0009] DE 10 2008 034 746 A1 describes a paint drying system for vehicle paint shops in which the process air quantity and the heating output are controlled depending on the pollutant concentration in the dryer.

[0010] WO 96 / 21833 A1 discloses an oven for drying and curing objects therein, in which the process air quantity and the heating power are controlled as a function of a temperature in the oven.

[0011] The invention is based on the object of creating an improved workpiece processing system and an improved method for operating a workpiece processing system with the lowest possible energy consumption.

[0012] This object is achieved by the teaching of the independent claims. Advantageous embodiments of the invention are the subject of the dependent claims.

[0013] The workpiece processing system according to the invention comprises a process chamber for receiving workpieces to be machined, which is connected to a process air line for introducing and / or discharging process air into or out of the process chamber; a heating device for heating process air to be introduced into the process chamber; and a control device for controlling a quantity of process air introduced into and / or discharged from the process chamber and for controlling a heating output of the heating device. The control device is designed such that it adapts the heating output of the heating device to the quantity of process air or the process air quantity control without detecting an additional measured variable relating to a pollutant concentration of the process air introduced into the process chamber and / or the process air discharged from the process chamber.

[0014] The combination of controls (i.e., settings, controls, and / or regulations) of the process air volume introduced into and / or discharged from the process chamber and the heating power of the heating device creates further energy savings potential. Furthermore, the combination of the two controls can result in synergistic effects that can reduce the metrological effort required for system control and thus the costs. The invention is based in particular on the following considerations.

[0015] The aim is to achieve demand-oriented and therefore energy-saving operation of the workpiece processing system. Demand-oriented means, for example, regulating the volume flow of the process air in the process chamber and the heating output of the connected heating device depending on production data or parameters (e.g. number of workpieces to be processed in the system). Such improved control is possible because, for example, with a reduced number of workpieces in the process chamber, the hydrogen and / or carbon input, in particular the input of organic solvents and / or other hydrocarbon compounds and / or other volatile, flammable, i.e. oxidizable substances into the system, is reduced. To ensure a constant, process-capable process chamber atmosphere, the required quantities of fresh air and exhaust air into and out of the process chamber are correspondingly reduced.The specific pollutant load of the exhaust air, which is typically given in the unit mass per volume (e.g. g / m 3< ), can be kept essentially constant due to the smaller number of workpieces in the process chamber. The increased residence time of the exhaust air in the heating device associated with the lower exhaust air volume flow - with a smaller number of workpieces - results in improved burnout (carbon monoxide content in the exhaust gas) and thus also improved emission values. Due to this effect, it is possible to reduce not only the fresh air and / or exhaust air volume flows but also the heating output of the heating device when the number of workpieces is smaller, while still complying with the prescribed emission values. Reducing the heating output of the heating device leads directly to energy savings.

[0016] Reducing the heating output of the heater can also extend the service life of the workpiece processing system. For example, simply reducing the exhaust air flow rate can result in very high preheating temperatures in the preheating and / or heating zone of the heater due to structural and / or process-related reasons. In this case, reducing the heating output of the heater can prevent potential damage, for example, due to thermal overload at the end of the preheating zone of the heater, especially in the case of maximum preheating.

[0017] By integrating the heating power control with the process air volume control, additional, usually complex measuring technology for recording the pollutant content in the exhaust air or clean air emitted by the heating device is no longer required.

[0018] In this context, the term "process air" encompasses all types of air flows that can be introduced into and / or discharged from the process chamber. This includes, in particular, fresh air introduced into the process chamber, exhaust air discharged from the process chamber, and recirculated air discharged from the process chamber and then returned to the process chamber. The term "air" encompasses any type of gaseous fluid. This includes, in particular, (ambient) air in the true sense of the word and gases, both with and without impurities or pollutants.

[0019] The control device is intended to control the process air volume and the heating output independently of one another or in relation to one another. In this context, a dependent control is understood in particular to mean controls in which there is a functional relationship between the two parameters, process air volume and heating output. Preferably, there is a fixed law for this functional relationship, preferably across the entire value range of the parameters. In this context, a referring control is understood in particular to mean controls in which different dependencies, laws or special rules apply in different value ranges of the parameters. Preferably, there is a tabular assignment between the values ​​of the two parameters, whereby this assignment can preferably be determined empirically.

[0020] When adjusting the heating power to the process air flow control or the process air flow to the heating power control, the allocation of heating power and process air flow cannot generally be proportional to each other with this integrated control. Alternatively, it can also be inversely proportional under certain circumstances, for example, if the heating power needs to be increased in a certain range with a reduced number of workpieces in order to still provide sufficient clean gas enthalpy for process heating with a reduced process air flow.

[0021] In a preferred embodiment of the invention, the process air line can comprise (at least) one fresh air line for introducing fresh air into the process chamber, (at least) one exhaust air line for discharging exhaust air from the process chamber, and / or (at least) one recirculation air line for discharging and reintroducing exhaust air from or into the process chamber. The control device is then preferably configured to control the fresh air flow, the exhaust air flow, and / or the recirculation air flow.

[0022] In a further preferred embodiment of the invention, the heating device can have a combustion chamber. The control device is then preferably configured to control a combustion chamber temperature of the combustion chamber. A change in the combustion chamber temperature can be achieved, for example, by changing the fuel gas supply.

[0023] In a further preferred embodiment of the invention, the heating device can comprise a thermal afterburner (TNV) connected to an exhaust air line connected to the process chamber for supplying exhaust air from the process chamber to the afterburner. The thermal afterburner is preferably configured to perform thermal oxidation, preferably regenerative or recuperative thermal oxidation, of the combustible pollutants in the exhaust air stream from the process chamber.

[0024] In yet another preferred embodiment of the invention, the heating device may comprise (at least) one recirculating air recuperator and / or (at least) one fresh air recuperator to which a clean gas resulting from combustion is fed.

[0025] The control device is preferably designed such that it controls the process air quantity as a function of at least one parameter selected from: Number and / or weight and / or type and / or surface area of ​​the workpieces accommodated in the process chamber; number and / or weight and / or type and / or surface area of ​​the workpieces fed to the process chamber per unit of time; volume flow, mass flow, temperature, quality (e.g. homogeneity of the density distribution, volatility, etc.) and / or quantity of the processing medium and / or fluid (e.g. paint, coating powder, adhesive or the like); pollutant content and / or temperature and / or humidity of the process air in the process chamber; and pollutant content and / or temperature and / or humidity of exhaust air discharged from the process chamber.

[0026] The control device is preferably designed such that it (when determining the heating power control as master) controls the heating power of the heating device in dependence on at least one parameter which is selected from: Number and / or weight and / or type and / or surface area of ​​the workpieces accommodated in the process chamber; number and / or weight and / or type and / or surface area of ​​the workpieces fed to the process chamber per unit of time; pollutant content and / or temperature of exhaust air discharged from the process chamber; pollutant content and / or temperature of a clean gas discharged from the heating device into the environment; temperature difference between circulating air discharged from the process chamber and reintroduced into the process chamber; temperature difference between exhaust air from the process chamber fed to a combustion chamber of the heating device and a clean gas discharged from the combustion chamber; and position of a clean gas or dosing flap which, depending on the opening angle, releases more or less clean gas enthalpy to the circulating air.

[0027] According to the invention, the heating output is adjusted without detecting an additional measured variable relating to a pollutant concentration of the process air introduced into the process chamber (clean air) and / or the process air discharged from the process chamber (exhaust air). This adjustment is preferably carried out using an empirically or theoretically determined control algorithm. This means that no additional measuring system is required to adjust the heating output; instead, the control device can rely on the data, parameters, measured variables, etc. already available to it.

[0028] In the method according to the invention for operating a workpiece machining system, workpieces to be machined are accommodated in a process chamber, wherein the process chamber is connected to a process air line for introducing and / or discharging process air into or out of the process chamber; process air to be introduced into the process chamber is heated by means of a heating device; and a heating output of the heating device is adapted to a process air quantity introduced into and / or discharged from the process chamber or the process air quantity control without recording an additional measured variable relating to a pollutant concentration of the process air introduced into the process chamber and / or the process air discharged from the process chamber.

[0029] This method can achieve the same advantages as the workpiece processing system of the invention described above. The above statements regarding advantages, definitions, and preferred embodiments apply accordingly.

[0030] The present invention is preferably applicable in drying and / or curing systems for drying and / or curing painted and / or coated and / or bonded workpieces. The workpieces are, for example, vehicle bodies or vehicle body parts.

[0031] The above and other advantages, features, and possible applications of the invention will become more clearly understood from the following description of various embodiments with reference to the accompanying drawings. These drawings show, mostly schematically: Fig. 1 shows the structure of a workpiece machining system according to a preferred embodiment of the invention; Fig. 2 shows the structure of a workpiece machining system according to various modifications of the embodiment of Fig. 1 ; Fig. 3 the structure of a workpiece machining system according to further modifications of the embodiment of Fig. 1 ; and Fig. 4 the structure of a workpiece machining system according to additional modifications of the embodiment of Fig. 3 .

[0032] Fig. 1 shows a workpiece processing system 10 according to an embodiment of the invention, which is configured, for example, as a drying and / or hardening system. The structure of this drying and / or hardening system 10 basically corresponds to that of WO 2010 / 122121 A2. With regard to the structure of the system, the functioning of the individual components, and possible modifications, reference is therefore made in its entirety to WO 2010 / 122121 A2.

[0033] The drying and / or curing system 10 can be part of a painting system. For example, the painting system can have one or more painting zones 12 in which workpieces 14 are painted. The drying and / or curing system 10 can be attached to these painting zones 12 and, in particular, can be arranged downstream in a conveying direction 16. A cooling zone (not shown) is generally arranged downstream of the drying and / or curing system 10, in which the workpieces 14 are cooled for further process steps or work steps. The drying and / or curing system 10 is particularly suitable for drying and / or curing painted and / or bonded components, in particular car bodies, body parts, or other assemblies (parts) of a land vehicle, water vehicle, or aircraft.

[0034] For example, in the Fig. 1 The workpiece 14 shown is designed as a painted body for a vehicle or aircraft. The workpiece 14 is mounted on a suitable carrier (skid) 15, which can be moved in a conveying direction 16 to transport the workpiece 14 from the painting zones 12 into and through the drying and / or curing system 10. The transport of the workpiece 14 can be continuous or discontinuous. However, the workpiece processing system 10 according to the invention is also suitable for other applications.

[0035] The drying and / or curing system 10 has a process chamber 18 with several zones 20-24. A first zone 20 is designed as a lock zone in the form of an inlet lock. A second zone 21 is designed as a first heating zone, and a third zone 22 is designed as a second heating zone. Furthermore, a fourth zone 23 is designed as a holding zone, and a final zone 24 is designed as a lock zone in the form of an outlet lock. During operation of the drying and / or curing system 10, the workpiece 14 first enters the inlet lock 20, wherein the inlet lock 20 seals the process chamber 18 of the drying and / or curing system 10 from the environment. This sealing also creates a certain thermal separation between the interior of the process chamber 18, which is heated, and the environment.The lock zones 20 and 24 are preferably designed such that, in particular, process air inside the process chamber 18 does not escape therefrom or such escape is at least largely avoided.

[0036] The first heating zone 21 and the second heating zone 22 enable heating of the workpiece 14 in stages (two in this embodiment). At full capacity, one or more workpieces 14 can be heated in each of the zones 21 and 22, with the workpiece 14 being transported to zone 22 after heating in zone 21 to allow further heating. One or more workpieces 14 can remain in the holding zone 23 for a certain period of time to dry and harden the workpiece 14 (optionally with the aid of electromagnetic radiation).Solvents in the form of aliphatic and / or aromatic hydrocarbons, fluorocarbons, fluorochlorohydrocarbons, esters, ketones, glycol ethers, alcohols, water, and the like then accumulate—depending on whether they are low-, medium-, or high-boiling components—primarily in the area of ​​the heating zones 21, 22 or the holding zone 23 in the air of the process chamber 18. However, the conditions under which the solvents escape in the drying and / or curing system 10 depend on the respective solvent or solvent component. Low-boiling components escape at low temperatures (< 100°C), medium-boiling components escape at medium temperatures (100°C to 150°C), and high-boiling components escape at high temperatures (> 150°C). A certain time may be specified for the drying and / or hardening process in the holding zone 23, after which the workpiece 14 is conveyed out of the drying and / or hardening system 10 via the lock zone 24.The glued and / or painted workpiece 14 is then dried and / or cured.

[0037] During operation of the drying and / or curing system 10, a certain exchange of the process air provided in the process chamber 18 is required. A certain amount of air can be taken from the drying and / or curing system 10 (exhaust air), which is then replaced with fresh air. This process air exchange is necessary because the air in the process chamber 18 becomes enriched with solvents that pass from a paint film or adhesive into the interior (usable space) of the process chamber 18 of the drying and / or curing system 10 during the drying and / or curing process, and this enrichment must be counteracted. This allows the solvent-enriched process air to be gradually, in particular continuously, exchanged to ensure that the process air can continue to absorb solvents.A certain threshold value can be specified here, which, in order to maintain a proper drying and / or curing process, should not be exceeded or should only be exceeded slightly, in particular within a limited time and / or space. This process air exchange takes place in a targeted manner, with exchange via the airlock zones 20, 24 being prevented as much as possible, since otherwise warm air from the process chamber 18 would be released into the environment in an undesirable manner or - if the fresh air is drawn into the process chamber 18 primarily via the airlock zones 20, 24 - too much cold outside air would be drawn into the process chamber 18.

[0038] The drying and / or curing system 10 further comprises a heating device 26-37. This heating device comprises a thermal afterburner (TNV) 26, at least one, preferably several (here: three) recirculating air recuperators 28, 30, 32, and usually one (in rare cases none) fresh air recuperator 34.

[0039] The thermal post-combustion device 26 is preferably designed as a post-combustion device for the regenerative or recuperative thermal oxidation of combustible pollutants in exhaust air from the process chamber 18 and preferably has a gas burner 36. The hot clean air generated by the gas burner 36 in a combustion chamber 37 is passed through the recuperators 28, 30, 32, 34 and then released into the atmosphere, as indicated by the arrow 38. This means that the hot exhaust gases (clean air) from the TNV 26 are used in the recuperators 28, 30, 32, 34 as an energy source for heating the circulating air or fresh air. Throttle valves are provided in each of the recuperators 28, 30, 32, 34 in order to use a certain part of the heat energy generated by the gas burner 36 in the respective recuperator and to pass the remaining part on to the next recuperator.

[0040] The recuperators 28, 30, 32, 34 further each have a heat exchanger 29, 31, 33, 35. The heat exchanger 29 of the first recirculating air recuperator 28 is assigned a suction side and an outlet side of a recirculating air line 40 connected to the first heating zone 21. The heat exchanger 29 is arranged in the recirculating air line 40 together with a fan. Depending on the position of the throttle valves of the first recirculating air recuperator 28, the recirculating air flowing through the heat exchanger 29 and recirculated into the first heating zone 21 is heated to a greater or lesser extent in order to achieve and maintain a certain temperature of the process air in the first heating zone 21 of the process chamber 18 during operation of the system 10.In a similar manner, the second heating zone 22 of the process chamber 18 is connected via a recirculation line 42 to the second recirculation recuperator 30, which has a heat exchanger 31 arranged in the recirculation line 42, and the holding zone 23 of the process chamber 18 is connected via a recirculation line 44 to the third recirculation recuperator 32, which has a heat exchanger 33 arranged in the recirculation line 44. Thus, the process air in the zones 21, 22, 23 can be heated and its temperature maintained at a desired level.

[0041] In addition, at least one exhaust air duct 46 is provided. According to Fig. 1 A suction side of this exhaust air line 46 is arranged in the holding zone 23 of the process chamber 18, and an outflow side of the exhaust air line 46 opens into the combustion chamber 37 of the TNV 26. The oxygen required for burning a fuel gas can thus be obtained from the exhaust air flowing from the holding zone 23 via the exhaust air line 46, this exhaust air being heated. The exhaust air from the holding zone 23 is thermally cleaned so that clean air is released into the atmosphere in the direction of arrow 38. A heat exchanger 27 is arranged in the exhaust air line 46 so that the exhaust air flowing into the combustion chamber 37 on the outflow side can be preheated. Also arranged in the exhaust air line 46 are a throttle valve 47 and a fan 48, which is designed in particular as a (frequency-)controlled fan.

[0042] In addition, the drying and / or curing system 10 has a fresh air line 50 with a fresh air inlet 52 through which fresh air can be drawn in. From the fresh air inlet 52, the fresh air is first guided via the fresh air line 50 through the fresh air recuperator 34, with the heat exchanger 35 arranged in the fresh air line 50. In this exemplary embodiment, the fresh air line 50 has a first outlet point at the lock zone 20 of the process chamber 18 and a second outlet point at the lock zone 24. Throttle valves are arranged upstream of these outlet points in order to regulate the proportion of the fresh air quantity supplied via the fresh air line 50 that is directed to the outlet points. Adjustable grilles or nozzles are optionally provided at individual or all outlet points in order to be able to adjust the flow rates.A fan 53, in particular a frequency-controlled fan, is also arranged in the fresh air line 50. In this exemplary embodiment, the fan 53 is arranged upstream of the heat exchanger 35 of the recuperator 34 in the fresh air line 50.

[0043] As in Fig. 1 As shown, the drying and / or curing system 10 further comprises a control device 55. This control device 55 is particularly designed such that, on the one hand, it controls the amount of fresh air introduced into the lock zones 20, 24 of the process chamber 18 via the fresh air line 50 and / or the amount of exhaust air discharged from the holding zone 23 of the process chamber 18 via the exhaust air line 46, and, on the other hand, it controls the heating power of the TNV 26. Furthermore, the control device 55 can also control the amount of recirculated air conducted via the recirculation lines 40, 42, 44.

[0044] For this purpose, the control device 55 is connected to a controller (e.g., an actuator) 56 of the fan 48 in the exhaust air line 46, to a controller (e.g., an actuator) 57 of the fan 53 in the fresh air line 50, and to a controller of the gas burner 36 in the combustion chamber 37 of the TNV 26. Alternatively or additionally, the control device 55 can also be connected to actuators of the throttles or throttle valves in the exhaust air line 46 or the fresh air line 50 and / or throttle valves / clean gas flaps for controlling the clean gas enthalpy in the recirculating air recuperators 28, 30, 32.

[0045] Deviating from or in addition to the Fig. 1 In the exhaust air line 46 shown, the suction side can also be arranged in one or more heating zones 21, 22 or in the transition between two successive zones 21, 22, 23 and / or 24. The suction side of an exhaust air line 46 is preferably arranged in the region of the maximum concentration of combustible pollutants in the process air in the process chamber 18 or in a region of the process chamber 18 following a section or region of maximum increase in the concentration of combustible pollutants in the process air. The suction side of an exhaust air line 46 is particularly preferably arranged downstream of the heating zone 21.If more than one exhaust air line 46 is provided, a controllable and / or adjustable throttle or shut-off valve 47 and / or a separate, controllable and / or adjustable fan 48 for controlling a flow through the respective exhaust air line 46 can be provided in at least one of the exhaust air lines 46, which are advantageously connected to the control device 55.

[0046] The control device 55 can take into account one or more parameters to control the amount of fresh air introduced into zones 20, 24 and the amount of exhaust air discharged from zone 23. Corresponding parameters are advantageously stored in the control software, whereby the parameters can be changed depending on the operation of the system 10. Since the amount of solvent introduced into the process chamber 18 varies during different operating states, for example during pause operation, partial load operation, or full load operation, the number of workpieces 14 accommodated in the process chamber 18 can serve as a parameter. As a rule, the amount of solvent introduced into the process chamber 18 varies in direct dependence on the number of workpieces 14, so that the fresh air and exhaust air quantities can be varied proportionally to the number of workpieces 14. As in Fig. 1 For this purpose, as shown, the control device 55 is connected to a workpiece detection device 60, which can detect the number of workpieces 14 conveyed into the process chamber 18 of the drying and / or curing system 10.

[0047] In this exemplary embodiment, a workpiece detection device 60 is provided, which is arranged in the conveying direction 16 between the lock zone 20 of the process chamber 18 of the drying and / or curing system 10 and the painting zone 12. Alternatively or additionally, at least one, preferably several, workpiece detection devices can be provided, which are / are connected downstream of the process chamber 18. In a further exemplary embodiment, such a separate workpiece detection device can be dispensed with if an indicator for the number of workpieces is defined in another way via the system control. Sensors or transmitting / receiving units that operate on the basis of electromagnetic waves, induction and / or weight force measurement are preferably considered as workpiece detection devices 60.The workpiece detection device(s) 60 can be configured, for example, as sensor(s) which, when the carrier 15 or the workpiece 14 passes, can transmit or transmits at least one clock signal or another measured variable relating to and / or characterizing the carrier 15 or the workpiece 14 to the control device 55. From the received clock signals, the control device 55 can then determine the current degree of utilization of the drying and / or curing system 10. Alternatively or additionally, the position of the workpiece in the dryer can be determined from the clock signals and / or another measured variable relating to and / or characterizing the carrier 15 or the workpiece 14 detected by the workpiece detection device 60. Further alternatively or additionally - if necessary or advantageous - the fresh air and / or exhaust air quantity can be determined from this position of the carrier 15 or the workpiece 14, from the process progress (e.g.The workpiece detection device 60 can be configured, in particular controlled and / or regulated, as a function of the position (e.g., position in the heating zone or holding zone) and / or the measured variable. However, the workpiece detection device 60 can also be configured as a reader, RFID reader, barcode reader, or the like. In such a configuration, the workpiece detection device 60 can, for example, detect a workpiece number of the workpiece 14 or information related to the workpiece 14.

[0048] Alternatively or additionally, it is also possible to consider other process parameters of the system 10, for example, a size of the workpiece 14, a material of the workpiece 14, and the like. Further process parameters that can be considered alternatively or additionally are a volume flow, a mass flow, a temperature, a quality (e.g., homogeneity of the density distribution, volatility, etc.), and / or a quantity of the processing medium and / or fluid (e.g., paint, coating powder, adhesive, or the like). The control device 55 can receive this information, for example, from a higher-level system control of the painting system.

[0049] In this way, an excessive accumulation of solvents that enter the process chamber 18 of the drying and / or curing system 10 from the paint film, an adhesive, or the like during the drying and / or curing process can be counteracted. For this purpose, sufficient fresh air can be continuously fed into the process chamber 18 and, at the same time, solvent-containing exhaust air can be discharged from the process chamber 18. The amount of exhaust air removed via the exhaust air line 46 can thus be replaced by a corresponding amount of fresh air. The amount of fresh air introduced and the amount of exhaust air discharged are selected such that condensate formation in the area of ​​the lock zones 20, 24 can be prevented and / or reduced. Furthermore, the amount of fresh air and the amount of exhaust air are optimized, i.e., selected to be as small as possible, in order to save energy.In particular, energy is required in the fresh air recuperator 34 to heat the fresh air supplied via the fresh air line 50, and its consumption can thus be optimized. In addition, thermal exhaust air purification is preferably carried out in the TNV 26 for the discharged exhaust air.

[0050] Further energy savings are achieved by the control device 55 by adjusting the heating output of the heating device 26-37, in particular the burner output of the TNV 26, to the fresh air and / or exhaust air volume control. This adjustment of the heating output can be carried out, optionally without additional measuring systems (e.g., for detecting the pollutant concentration in the clean air, for example, downstream of the TNV 26 in the clean air or upstream of the TNV 26 in the exhaust air), based on the production data and parameters supplied by the system 10, which are already used by the control device 55 for fresh air and / or exhaust air volume control.

[0051] The control device 55 enables demand-based and thus energy-saving operation of the drying and / or curing system 10. The improved system control proposed here is possible because, for example, with a reduced number of workpieces 14 in the process chamber 18, the water and carbon input, in particular the solvent and / or hydrocarbon input into the system 10 is reduced. For a constant, process-capable process chamber atmosphere, the required volume flows of the fresh air to be introduced into the process chamber 18 and the exhaust air to be discharged from the process chamber 18 are correspondingly reduced. The specific pollutant load of the exhaust air, which is typically specified in the unit mass per volume (e.g. g / m 3< ), remains essentially constant due to the smaller number of workpieces in the process chamber 18.The increased residence time of the exhaust air in the TNV 26, which is associated with the lower exhaust air volume flow, results in improved burnout and thus also improved emission values ​​for the clean air. This makes it possible to reduce not only the fresh air and / or exhaust air volume flows, but also the burner output of the TNV 26 with a smaller number of workpieces, while still complying with the prescribed emission values.

[0052] Reducing the combustion chamber temperature of the TNV 26 also makes technical sense and may be necessary, since a mere reduction in the exhaust air flow rate can, due to structural reasons, result in very high preheat temperatures in the heating zone of the TNV 26. Possible consequences include system damage, for example, due to thermal overload at the end of the preheating zone of the TNV 26. It is therefore advantageous to combine the process air flow control with the combustion chamber temperature control into an integrated overall control system.

[0053] As explained above, this combination can be implemented in such a way that the fresh air and / or exhaust air volume control takes precedence over the combustion chamber temperature control. An increase or decrease in the exhaust air volume flow through the exhaust air duct 46 would then automatically result in an increase or decrease in the combustion chamber temperature. The underlying control algorithm can be adapted, for example, through reference measurements as part of the emission value settings on the TNV 26 for the present system 10.

[0054] The control device 55 can control the amount of fresh air and / or the amount of exhaust air into or out of the process chamber 18 of the drying and / or curing system 10 preferably depending on one or more of the following process parameters of the system 10: Number and / or weight and / or type and / or surface area of ​​the workpieces 14 accommodated in the process chamber 18; number and / or weight and / or type and / or surface area of ​​the workpieces 14 fed into the process chamber 18 per unit of time.

[0055] Other possible process parameters on the basis of which fresh air and / or exhaust air volume control can be carried out are: Volume flow, mass flow, temperature, quality and / or quantity of the processing medium and / or fluid; pollutant content and / or temperature and / or humidity of the process air in the process chamber 18; pollutant content and / or temperature and / or humidity of the exhaust air discharged from the process chamber 18.

[0056] Alternatively, the control device 55 can also provide a control architecture in which the control of the combustion chamber temperature of the TNV 26 can be carried out as a function of certain process parameters of the system 10 (master) with automatic adjustment of the fresh air and / or exhaust air volume flow (slave).

[0057] The control device 55 can also preferably control the combustion chamber temperature of the TNV 26 depending on one or more of the following process parameters of the system 10: Number and / or weight and / or type and / or surface area of ​​the workpieces 14 accommodated in the process chamber 18; number and / or weight and / or type and / or surface area of ​​the workpieces 14 fed into the process chamber 18 per unit of time.

[0058] Other possible process parameters on the basis of which the combustion chamber temperature can be controlled are: Pollutant content and / or temperature of the exhaust air discharged from the process chamber 18; pollutant content and / or temperature of the clean gas discharged from the heating device 26-37 into the environment; temperature difference between the circulating air discharged from the process chamber and reintroduced into the process chamber (zones 21, 22, 23); temperature difference between the exhaust air from the process chamber 18 fed to the combustion chamber 37 of the TNV 26 and the clean gas discharged from the combustion chamber 37; position of a clean gas or dosing flap which releases more or less clean gas enthalpy to the circulating air depending on the opening angle.

[0059] Finally, a fundamentally equal arrangement of the process air flow control and the combustion chamber temperature control is also conceivable. This means that the respective master / slave relationship of these two controls by the control device 55 is only determined during operation of the drying and / or curing system 10, depending on the current production data or parameters.

[0060] Referring to Fig. 2 Various modifications of the drying and / or curing system 10 are now carried out by Fig. 1 which can be provided individually or in any combination.

[0061] As mentioned above, the control device 55 can optionally also use at least one condition parameter (e.g. humidity, temperature, pollutant content) of the process air in the process chamber 18 as a further process parameter. As in Fig. 2 Therefore, as shown, a corresponding process air sensor 62 can optionally be mounted in / on the process chamber 18. While this process air sensor 62 in Fig. 2 is positioned in / at the lock zone 20, one or more process air sensors can alternatively or additionally also be provided in / at one or more of the other zones 21-24 of the process chamber 18. The process air sensor(s) 62 can, for example, be designed as a humidity meter or hygrometer to determine the humidity, as a thermometer, infrared sensor, thermoelectric element or the like to determine the temperature, and / or as a flame ionization detector (FID), pellistor, electrochemical cell, optical gas sensors, galvanic concentration cell or the like to determine a pollutant content.

[0062] As already mentioned above, the control device 55 can optionally also use a condition parameter (e.g. temperature, pollutant content) of the exhaust air discharged from the process chamber 18 through the exhaust air line 46 as a further process parameter. As in Fig. 2 Therefore, as shown, at least one corresponding exhaust air sensor 64 can optionally be mounted in / on the exhaust air line 46. Alternatively or additionally, the exhaust air sensor 64 can also be arranged or provided in the process chamber 18, preferably in the zone from which the extraction can or does take place by means of the extraction line, in particular in the region of the extraction side of the extraction line 46. The exhaust air sensor 46 is in particular intended, provided and / or designed to determine at least one quality, property and / or state parameter, in particular a humidity, temperature and / or pollutant content of the exhaust air or the process air to be extracted.The exhaust air sensor(s) 64 can be designed, for example, as a humidity meter or hygrometer to determine the humidity, as a thermometer, infrared sensor, thermoelectric element or the like to determine the temperature and / or as a flame ionization detector (FID), pellistor, electrochemical cell, optical gas sensors, galvanic concentration cell or the like to determine a pollutant content.

[0063] As already mentioned above, the control device 55 can optionally also use a state parameter (e.g. humidity, temperature, pollutant content) of the clean air 38 emitted by the heating device 26-37 as a further process parameter. As in Fig. 2 Therefore, as shown, a corresponding clean air sensor 66 can optionally be provided downstream of the heating device. Alternatively or additionally, a clean air sensor can also be provided between the TNV 26 and the first recirculating air recuperator 28. The clean air sensor 66 can, for example, be designed as a humidity meter or hygrometer to determine humidity, as a thermometer, infrared sensor, thermoelectric element, or the like to determine temperature, and / or as a flame ionization detector (FID), pellistor, electrochemical cell, optical gas sensors, galvanic concentration cell, or the like to determine pollutant content.

[0064] As in Fig. 2 illustrated, various further exhaust air ducts 68, 70, 72, 74 may also be provided.

[0065] As with exhaust air line 46, a suction side of the additional exhaust air line 68 is arranged in the holding zone 23 of the process chamber 18. This additional exhaust air line 68 is connected to the fresh air line 50 in order to mix the fresh air from the fresh air inlet 52 with the exhaust air from the additional exhaust air line 68. This mixture of fresh air and exhaust air is supplied via the fresh air line 50 to the lock zones 20, 24 of the process chamber 18. A fan with adjustable throughput, in particular a frequency-controlled fan, and a throttle valve are preferably arranged in the additional exhaust air line 68. In this embodiment, the control device 55 preferably takes into account a third criterion in addition to the two criteria of energy saving and condensate avoidance, namely the limitation of the solvent concentration to below 25% of the lower explosion limit (LEL).To meet these criteria, a certain amount of exhaust air must be removed from the holding zone 23. The exhaust air removed from the process chamber 18 via the exhaust air line 46 is subjected to thermal exhaust air purification in the combustion chamber 37 of the TNV 26, while the portion of the exhaust air discharged from the holding zone 23 via the additional exhaust air line 68 and introduced into the lock zones 20, 24 together with the fresh air serves as recirculated air with respect to the entire drying and / or curing system 10 and can distribute the solvent-enriched process air throughout the process chamber 18. This reduces a high concentration of solvents in the process air of the holding zone 23, while the thermal energy is retained and thus the energy requirement can be further reduced. In addition, the portion of the exhaust air volume conducted via the additional exhaust air line 68 can replace part of the supplied fresh air volume.The air mixture of exhaust air and fresh air entering the lock zones 20, 24 is heated and relatively low in solvent when it comes into contact with the lock recirculating air in the lock zones 20, 24, which is why condensate formation in these zones 20, 24 can be counteracted. Alternatively or additionally, the exhaust air serving as recirculating air can also be taken from another zone of the process chamber 18, for example, the first heating zone 21 and / or the second heating zone 22.

[0066] Exhaust air serving as recirculating air can be removed from the holding zone 23 of the process chamber 18 via a further exhaust air line 70, 72 and preferably fed directly, i.e., without mixing with fresh air, to the lock zones 20, 24. The two further exhaust air lines 70, 72 can optionally have separate suction points or a common suction point in the holding zone 23.

[0067] Via a further exhaust air line 74, exhaust air serving as recirculating air can be removed from the first heating zone 21 of the process chamber 18 and fed to the lock zone 20. This allows a certain amount of exhaust air to be directed from the first heating zone 21 into the lock zone 20.

[0068] Although not shown, fans, throttles or throttle valves, filter devices and / or exhaust air sensors 64 may also be provided in the further exhaust air ducts 68, 70, 72, 74.

[0069] Referring to Fig. 3 Various further modifications of the drying and / or curing system 10 are Fig. 1 These further modifications may be used individually or in any combination and / or in any combination with one or more combinations of Fig. 2 be provided.

[0070] As in Fig. 3 As shown, an intermediate lock 25 can optionally be provided between the first heating zone 21 and the second heating zone 22. A branch line 51 branches off from the fresh air line 50, via which a fresh air flow curtain can be generated in the intermediate lock 25 by means of a nozzle.

[0071] Furthermore, it is possible to supply fresh air to one or more of the recirculation lines 40, 42, 44. For this purpose, a further fresh air line 76 is provided, which branches off, for example, upstream and / or downstream of the heat exchanger 35 of the fresh air recuperator 34 and opens into the corresponding recirculation line 40, 42, 44, for example, downstream of the heat exchanger 29, 31, 33 of the respective recirculation recuperator 28, 30, 32.

[0072] Further variants of the drying and / or curing system 10 have a flow measuring device 78 on the further fresh air line 76 and / or a flow measuring device 79 on the fresh air line 50.

[0073] Referring to Fig. 4 various additional modifications of the drying and / or curing system 10 of Fig. 1 explained, whereby these are considered here as supplementary modifications to the execution according to Fig. 3 However, these additional modifications may also be used individually or in any combination and / or in any combination with one or more combinations of Fig. 2 be provided.

[0074] In addition to, for example, Fig. 3 At least one further exhaust air line 46 is provided, the suction side of which is arranged at the intermediate lock 25. In at least one exhaust air line 46, a throttle valve 47, a fan 48 and / or an exhaust air sensor 64 can be provided or arranged, which advantageously characterize, determine and / or establish a flow through the respective exhaust air line 46. The throttle valve 47 and / or the fan 48 are advantageously connected to an output line of the control device 55, the exhaust air sensor 64 in particular to an input line. With regard to the type and function of the exhaust air sensor 64, reference is made at this point to the description of the exemplary embodiment according to Fig. 2 referred to.

[0075] Optionally, it can further be provided that a clean air sensor 66 is provided in a path or line of the clean air, as already described in the explanations for Fig. 2 described, to which reference is made here.

[0076] As already mentioned in the description of Fig. 1 described, the heating device 26-37, in particular the TNV 26, is Fig. 4 a control flap for controlling a fuel or fuel-air mixture supply is shown, which is connected to an output line of the control device 55. In addition to this control flap, the heating device 26-37, in particular the TNV 26, can optionally also be connected to an output of the control device 55 with respect to an ignition device (not shown) and / or to a combustion chamber monitoring sensor (likewise not shown), whereby the control can advantageously also initiate an ignition process and / or monitor the ignition and / or the combustion process.

[0077] In a further modification according to Fig. 4It is further provided that, in addition to or as an alternative to the data of the workpiece detection device 60, the control device 55 can be supplied with process and / or product data 12A from the upstream painting and / or coating and / or bonding process, in particular from the painting, coating and / or bonding system, preferably from the painting cells 12, and / or can be queried by the latter. For the workpiece processing system 10 according to the invention or the method according to the invention, process and / or product data 12A on the work material used (e.g. paint, coating material, adhesive and / or auxiliaries, in particular with regard to composition, physical / chemical properties, etc.), application properties (e.g. layer thickness) and / or workpiece properties (e.g. mass, volume, surface, shape) are particularly important.These can be supplied, provided, and / or queried by the control device 55, for example, from a process computer of the upstream painting and / or coating and / or bonding process, for example via a data bus. Alternatively or additionally, it can also be provided that these process and / or product data 12A are passed on to the workpiece 14 or the carrier 15 or with them and are preferably read out by the workpiece detection device 60 or another reading unit and forwarded to the control device 55 for processing. Thus, certain parameter values, intervals, and / or groups can be encoded in a preferably machine-readable code (e.g., barcode, QR code), wherein the control device 55 advantageously has a corresponding decoding unit in order to evaluate the thus encoded process and / or product data 12A for processing.Alternatively or additionally, process and / or product data 12A can be stored in coded or uncoded form in a memory element on the workpiece 14 and / or carrier 15 for retrieval, wherein the workpiece detection device 60 or another reading unit of the workpiece processing system 10 advantageously reads out the process and / or product data 12A required for control. Additionally, a writing unit can be provided, for example, in or after the discharge zone 24, which writes process and / or product data 10A of the workpiece processing in the workpiece processing system 10 in the memory element of the workpiece 14 and / or carrier 15. Alternatively or additionally, the control unit 55 can also forward the process and / or product data 10A to a process control computer.

Claims

1. A workpiece processing installation (10), in particular for drying and / or curing painted and / or coated and / or glued workpieces, comprising: a process chamber (18) for receiving workpieces (14) to be processed, wherein the process chamber (18) is connected to a process air line (40, 42, 44, 46, 50) for introducing and / or discharging process air into or out of the process chamber, respectively; a heating device (26-37) for heating a process air to be introduced into the process chamber (18); and a control means (55) for controlling a process air volume introduced into the process chamber and / or discharged from the process chamber and for controlling a heating power of the heating device, characterized in that the control means (55) is configured to adjust the heating power of the heating device, without detecting an additional measured variable relating to a pollutant concentration of the process air introduced into the process chamber (18) and / or of the process air discharged from the process chamber (18), to the process air volume or the process air volume control.

2. The workpiece processing installation according to claim 1, wherein the process air line (40, 42, 44, 46, 50) comprises a fresh air line (50) for introducing fresh air into the process chamber, an exhaust air line (46) for discharging exhaust air from the process chamber and / or a recirculation air line (40, 42, 44) for discharging and reintroducing exhaust air from and into the process chamber, respectively; and the control means (55) is configured to control the fresh air volume, the exhaust air volume and / or the recirculating air volume.

3. The workpiece processing installation according to one of the preceding claims, wherein the heating device (26-37) comprises a combustion chamber (37); and the control means (55) is configured to control a combustion chamber temperature of the combustion chamber (37).

4. The workpiece processing installation according to one of the preceding claims, wherein the heating device (26-37) comprises a thermal post-combustion device (26) connected to an exhaust air line (46) connected to the process chamber (18) for supplying exhaust air from the process chamber into the post-combustion device (26).

5. The workpiece processing installation according to one of the preceding claims, wherein the heating device (26-37) comprises a recirculating air recuperator (28, 30, 32) and / or a fresh air recuperator (34); and a clean gas resulting from combustion is supplied to the recirculating air recuperator (28, 30, 32) and / or the fresh air recuperator (34).

6. The workpiece processing installation according to one of the preceding claims, wherein the control means (55) is configured to control the process air volume depending on at least one parameter selected from: - number and / or weight and / or type and / or surface area of the workpieces (14) received in the process chamber (18); - number and / or weight and / or type and / or surface area of the workpieces (14) fed to the process chamber (18) per time unit; - volume flow, mass flow, temperature, quality and / or quantity of the processing medium and / or fluid; - pollutant content and / or temperature and / or humidity of the process air in the process chamber (18); - pollutant content and / or temperature and / or humidity of an exhaust air discharged from the process chamber (18).

7. The workpiece processing installation according to one of the preceding claims, wherein the control means (55) is configured to control the heating power of the heating device depending on at least one parameter selected from: - number and / or weight and / or type and / or surface area of the workpieces (14) received in the process chamber (18); - number and / or weight and / or type and / or surface area of the workpieces (14) fed to the process chamber (18) per time unit; - pollutant content and / or temperature of an exhaust air discharged from the process chamber (18); - pollutant content and / or temperature of a clean gas discharged from the heating device (26-37) into the environment; - temperature difference of a recirculating air discharged from the process chamber and reintroduced into the process chamber; - temperature difference between an exhaust air from the process chamber (18) supplied to a combustion chamber (37) of the heating device and a clean gas discharged from the combustion chamber; - position of a clean gas or metering flap.

8. A method for operating a workpiece processing installation (10), in particular for drying and / or curing painted and / or coated and / or glued workpieces, wherein workpieces (14) to be processed are received in a process chamber (18), wherein the process chamber (18) is connected to a process air line (40, 42, 44, 46, 50) for introducing and / or discharging process air into or out of the process chamber, respectively; and a process air to be introduced into the process chamber (18) is heated by means of a heating device (26-37), characterized in that a heating power of the heating device is adjusted, without detecting an additional measured variable relating to a pollutant concentration of the process air introduced into the process chamber (18) and / or of the process air discharged from the process chamber (18), to a process air volume introduced into the process chamber and / or discharged from the process chamber or to the process air volume control.

9. The method according to claim 8, wherein the process air volume is controlled depending on at least one parameter selected from: - number and / or weight and / or type and / or surface area of the workpieces (14) received in the process chamber (18); - number and / or weight and / or type and / or surface area of the workpieces (14) fed to the process chamber (18) per time unit; - volume flow, mass flow, temperature, quality and / or quantity of the processing medium and / or fluid; - pollutant content and / or temperature and / or humidity of the process air in the process chamber (18); - pollutant content and / or temperature and / or humidity of an exhaust air discharged from the process chamber (18).

10. The method according to claim 8 or 9, wherein the heating power of the heating device is controlled depending on at least one parameter selected from: - number and / or weight and / or type and / or surface area of the workpieces (14) received in the process chamber (18); - number and / or weight and / or type and / or surface area of the workpieces (14) fed to the process chamber (18) per time unit; - pollutant content and / or temperature of an exhaust air discharged from the process chamber (18); - pollutant content and / or temperature of a clean gas discharged from the heating device (26-37) into the environment; - temperature difference of a recirculating air discharged from the process chamber and reintroduced into the process chamber; - temperature difference between an exhaust air from the process chamber (18) supplied to a combustion chamber (37) of the heating device and a clean gas discharged from the combustion chamber; - position of a clean gas or metering flap.

Images