Coating agent supply and associated operating procedures

Abstract

The invention relates to a coating agent supply for supplying a coating system (e.g. painting system) for coating components (e.g. motor vehicle body components) with a coating agent (e.g. paint), with • a coating agent source (18) for providing the coating agent, • a coating agent system (49) which is filled with the coating agent during operation (e.g. pump circuit, central channel), • a coating agent pump (19) for conveying the coating agent from the coating agent source (18) and for filling the coating agent system (49) with the coating agent, and • a coating agent return (26) for receiving excess coating agent when filling the coating agent system (49) with the coating agent, and • a return sensor (33) for detecting an incipient coating agent flow of the coating agent into the coating agent return (26) when filling the coating agent system (49). Furthermore, the invention comprises a corresponding operating method.

Description

Technical Field of the InventionThe invention relates to a coating agent supply for supplying a coating system (e.g. paint system) for coating components (e.g. motor vehicle body components) with a coating agent (e.g. paint).BACKGROUND OF THE INVENTIONIn modern painting installations for painting motor vehicle body components, the paint to be applied is usually provided in large-volume paint containers. The paint is then sucked by a paint pump from the respective paint container and conveyed via a pump circuit and further line systems to an application device (e.g. atomizer, print head). Before the actual painting operation, the pump circuit must be filled with the paint, which takes place in a so-called charging cycle in a time-controlled manner with a predetermined filling duration. During this charging cycle with the predetermined filling duration, the paint pump delivers the paint from the paint container into the pump circuit, whereby the pump circuit is filled with the paint. In order to ensure a paint change without paint entrainment, paint and any residual washing agent present from preceding process steps is then discarded in this filling process into a return. The filling time actually required depends on the viscosity of the paint, the length of the hose and the suction behavior of the paint pump. The filling duration must therefore be chosen to be so great that even with the highest paint viscosity, the longest hose length and the worst suction behavior of the paint pump, it is nevertheless ensured that the pump circuit is completely filled with the paint within the filling duration. However, this leads to a situation in which, in practice, a more or less large amount of paint is discarded into the recirculation. This applies in particular when using low-viscosity paints, which can be sucked in and conveyed more easily, so that then unnecessarily much paint is discarded in the return line, because the filling time is not adapted to the actual circumstances (e.g. paint viscosity, hose length, suction behavior of the paint pump).Disadvantages of the known paint supplies in paint systems are therefore the paint losses during filling of the pump circuit and the associated outlay for disposal of the discarded paint quantity.DESCRIPTION OF THE INVENTIONThe object of the invention is therefore to reduce paint losses during the filling of the pump circuit of a paint system.This object is achieved by a coating agent supply according to the invention or by an associated operating method according to the independent claims.The coating agent supply according to the invention first comprises, in accordance with the prior art, at least one coating agent source in order to provide the coating agent. The coating agent source is preferably a large-volume coating agent storage container, as are known from paint systems for painting motor vehicle body components. Alternatively, however, it is possible for the coating agent source to be a ring line or another coating agent source.It should be mentioned here that the invention is not restricted to lacquers with regard to the coating agent, but can also be realized in principle with other types of coating agents, such as, for example, with insulating materials, sealants or adhesives, to name just a few examples.In addition, the coating agent supply according to the invention is not restricted to the preferred use in a paint system for painting motor vehicle body components.In addition to the aforementioned coating agent source, the coating agent supply according to the invention in accordance with the prior art has a coating agent system which is to be filled with the coating agent during operation.For example, the coating agent system to be filled can be a pump circuit, as already mentioned in the introduction to the prior art. In this case, the pump circuit generally comprises the volume of the coating agent pump to be filled, the suction and pressure hoses and the associated valve stations.However, it is also possible within the scope of the invention for the coating agent system to be filled to be a central channel of a pig system, wherein the central channel can optionally be connected to one of a plurality of pig lines, as is known from the German patent application DE 10 2023 102 825.1, so that the content of this earlier patent application is fully attributable to the present description of the invention.Furthermore, the coating agent supply according to the invention also has, in accordance with the prior art, a coating agent pump which delivers the coating agent from the coating agent source (e.g. coating agent storage container) into the coating agent system to be filled (e.g. pump circuit, central channel).In addition, the coating agent supply according to the invention also has a coating agent recirculation in accordance with the prior art described at the beginning, in order to be able to discharge excess coating agent into the coating agent recirculation during the filling of the coating agent system (e.g. pump circuit, central channel).The coating agent supply according to the invention is now characterized by a recirculation sensor in order to be able to detect an beginning of the coating agent flow of the coating agent into the coating agent recirculation when the coating agent system (e.g. pump circuit, central channel) is being filled. The detection of the beginning of the coating agent flow into the coating agent recirculation during the filling of the coating agent system offers the possibility of ending the filling process immediately after the filling of the coating agent system, so that the amount of coating agent discarded into the coating agent recirculation can be minimized.In a variant of the invention, the recirculation sensor is part of a self-medium-actuated shut-off valve ("paint stop valve"), wherein the shut-off valve is controlled by the coating agent applied to the shut-off valve. The shut-off valve is designed in such a way that the shut-off valve opens the flow path into the coating agent recirculation line as long as the coating agent system (e.g. pump circuit, central channel) has not yet been filled with the coating agent and the coating agent therefore has not yet flowed into the coating agent recirculation line. The shut-off valve, on the other hand, closes automatically as soon as the coating agent system (e.g. pump circuit, central channel) is filled with the coating agent and the coating agent therefore flows into the coating agent recirculation. The self-medium-actuated shut-off valve is thus automatically controlled by the coating agent flowing into the coating agent recirculation. The return sensor integrated into the shut-off valve preferably works purely mechanically in this case. Such self-medium-operated shut-off valves are known per se from the prior art and therefore need not be described in more detail. Examples of such shut-off valves are described, however, in German patent application DE 10 2009 020 064 A1, so that the content of this earlier patent application is fully attributable to the present description with regard to the structural design and the mode of operation of the self-medium-actuated shut-off valve.It should be mentioned here that the self-medium-actuated shut-off valve should be designed such that it can also open at a system pressure of 20 bar, as may be required during the operation of painting installations. Thus, the shut-off valve (paint stop valve) can usually assume an open, a closed or a middle position, wherein the open valve position and the closed valve position can be actively controlled. The shut-off valve (paint stop valve) closes automatically as soon as medium arrives there. The closing function takes place within a certain viscosity range, for example also in the case of a solvent-paint mixture. A safety function ensures that a small amount of the medium is "over-pressed". The shut-off valve (paint stop valve) which was closed shortly before is again opened actively briefly for this purpose, counter to the system pressure which can be a maximum of 20 bar. This ensures that virtually pure paint is present at the paint stop valve. During a filling process, a solvent-paint mixture is thus first forced into the recirculation line, which already leads to automatic closing of the shut-off valve (paint stop valve), although the paint system is not yet completely filled with paint but is still partially filled with solvent. The brief opening of the shut-off valve (paint stop valve) then allows the remaining solvent to escape, so that the paint system to be filled is then filled exclusively with the paint and no longer contains any solvent. For this brief opening of the shut-off valve (paint stop valve), it is important that it is designed such that it can also open at a system pressure of 20 bar.Alternatively, however, there is a possibility that the recirculation sensor is separated from the shut-off valve. For example, the feedback sensor can be a capacitive sensor which detects by a capacitive measurement whether coating agent flows into the coating agent feedback via a feedback line or not. For example, such a capacitive sensor can be fastened for this purpose on the outer wall of the return line, for example by one or more clamping straps.However, the return sensor can alternatively also be an optical sensor, which can have a light barrier, for example, in order to detect the coating agent flow of the coating agent into the return of the coating agent.However, the invention is not limited to the two examples mentioned above (capacitive sensor, optical sensor) with regard to the mode of operation of the feedback sensor, but can also be realized in principle with other sensor types. For example, purely mechanical sensors, ultrasonic sensors or magnetic-inductive flow meters (MID) can also be used as feedback sensor within the scope of the invention, just to name a few examples.In the variant of the invention described above with a separate feedback sensor (e.g. capacitive or optical sensor), a controller (e.g. PLC: programmable logic controller) is preferably also provided, which is connected on the input side to the feedback sensor in order to be able to detect when coating agent flows into the coating agent feedback during the filling of the coating agent system, which indicates that the coating agent system to be filled is completely filled. The controller may then take various actions to prevent an unnecessarily large amount of coating agent from being discarded into the coating agent recirculation. A possible reaction of the control is that the control stops the coating agent pump, whereby the filling process is ended. Another possible reaction of the control is that the control closes a controllable shut-off valve, which either releases or blocks the coating agent flow into the coating agent recirculation. These two reactions of the control can also be combined with one another, i.e. the control can stop the coating agent pump and additionally close the shut-off valve when the recirculation sensor detects the beginning of the coating agent flow into the recirculation.In a preferred exemplary embodiment of the invention, the coating material system to be filled has a non-piggable pump circuit which is preferably arranged in a paint mixing chamber of a paint shop and has the following components:• The coating agent source (e.g. paint reservoir),• the coating agent pump,• a first pig station ("pig source station"),• a non-piggable feed line from the coating agent source via the coating agent pump to the first pigging station, and• a non-piggable return line from the first pigging station back to the coating agent source.Such a non-piggable pump circuit is known per se from the already above-mentioned German patent application DE 10 2023 102 825.1, so that the content of this earlier patent application is fully incorporated into the present description.In this case, it is possible for a plurality of different coating agent sources (e.g. paint storage containers) for different-colored coating agents to be provided in the paint mixing space of the painting installation. Each of these coating agent sources can then be provided with a separate non-piggable pump circuit in order to convey the respective coating agent to the first pigging station. The first pig station ("pig source station") can then have a valve unit in order to select one of the supplied coating agents. This is also known per se from the already above-mentioned German patent application DE 10 2023 102 825.1, so that the content of this earlier patent application is fully incorporated into the present description.The aforementioned coating agent recirculation for the recirculation of excess coating agent during the filling of the pump circuit then preferably branches off from the feed line of the non-piggable pump circuit, for example at a two-way valve in the feed line to the first pig station ("pig source station").Furthermore, in the context of the invention, it is possible for the coating agent system to be filled to have a coating agent circuit, in particular a paint mixing space circuit or pump and paint mixing space circuit, having the following components:• a first pigging station ("pig swelling station"), which is fed on the input side with the coating agent from the coating agent source via a coating agent feed line from the coating agent pump, wherein the first pigging station is preferably arranged within a paint mixing chamber of the coating plant,• a second pigging station ("pig-target station"), wherein the second pigging station is preferably arranged outside the ink mixing space of the coating plant,• a piggable feed line from the first pigging station to the second pigging station, and• a piggable return line from the second pigging station to the first pigging station.Such a coating circuit is also known per se from the already above-mentioned German patent application DE 10 2023 102 825.1, so that the content of this earlier patent application is fully incorporated into the present description.It has been mentioned above that the piggable coating agent circuit is fed with the coating agent from a coating agent feed line. If the coating agent circuit comprises a piggable ink mixing space circuit, the non-piggable pump circuit described above can assume the function of the coating agent feed line, wherein the non-piggable pump circuit has a run-in line and a return line and thus enables material circulation. However, it is alternatively also possible for the ink mixing space circuit to be non-piglable and to be fed directly from the coating agent source without a separate pump circuit.In the coating agent circuit described above, the coating agent recirculation line with the associated recirculation sensor can branch off from different points. For example, the coating agent recirculation can branch off from the pump circuit at the first pig station ("pig source station"). Alternatively or additionally, there is also the possibility that the coating agent recirculation branches off from the coating agent supply line to the first pig station, in particular at a double valve in the coating agent supply line to the first pig station.In the non-piggable pump circuit described above, the first pigging station (pig swelling station) is preferably located in the paint mixing space of the painting facility, while the second pigging station (pig destination station) is preferably located outside the paint mixing space, for example at a transfer point for supplying a plurality of painting booths. At the transfer point, a third pig station (pig source station) is then preferably also arranged, which is connected to the second pig station via a non-piggable central channel. The third pig station is in turn connected via a pig line to a fourth pig station (pig target station), which is preferably located at a removal point in a coating booth. This arrangement is known in principle from the German patent application DE 10 2023 102 825.1 already described above, so that the content of this earlier patent application is fully incorporated into the present description.In this configuration with a total of four pig stations, a coating agent recirculation with an associated recirculation sensor can also branch off from the central channel between the second pig station (pig target station) and the third pig station (pig source station).In this case, a plurality of coating agent circuits can be provided in order to be able to supply a plurality of different coating agents. The coating agent circuits are then fed on the input side from a respective coating agent source. On the output side, the coating agent circuits are connected to a distributor station which selects one of the coating agent circuits and connects it to the third pig station. This arrangement is also known in principle from the German patent application DE 10 2023 102 825.1 already described above, so that the content of this earlier patent application is fully incorporated into the present description.It has already been mentioned above that the coating agent source is preferably a coating agent reservoir, which can preferably have a large capacity of at least 1 liter, 2 liters, 5 liters, 10 liters, 50 liters or even 100 liters. Such large-volume paint containers are known per se from the prior art and therefore need not be described in more detail.The coating agent pump is preferably a suction pump within the scope of the invention, which is preferably electrically driven.It should also be mentioned in general that the components to be coated are preferably motor vehicle body components, the coating agent then being a paint. However, it has already been mentioned above that the invention is not restricted to lacquers or motor vehicle body components with regard to the coating agent and also with regard to the components to be coated.It should also be mentioned that the non-piggable central channel to be filled is preferably relatively short and thus has a length of at most 1 m, 50 cm, 25 cm, 15 cm, 10 cm or 5 cm.The first and the second pig station, on the other hand, can be arranged at a relatively large distance from one another, which can be, for example, more than 2 m, 5 m, 10 m, 20 m, 50 m, 100 m or 150 m. This allows the first pig station (pig source station) to be arranged in the paint mixing space, while the second pig station (pig destination station) is located outside the paint mixing space close to the paint booths.It should also be mentioned that the applicator for coating the components is preferably a print head or an atomizer (e.g. rotary atomizer). These types of applicators are known per se from the prior art and therefore need not be described in more detail.It should also be mentioned that the coating agent supply according to the invention can have a plurality of coating agent storage containers as coating agent sources, for example more than two, three, four or more than five coating agent storage containers, which can then provide different coating agents. Each of these coating agent storage containers can then be assigned a non-piggable ink mixing space circuit and / or a non-piggable pump circuit.The coating agent supply according to the invention has been described above independently of the coating plant to be supplied. However, the invention also claims protection for a coating plant according to the invention which has the coating agent supply described above. In addition, the coating plant according to the invention then also contains further components, such as painting robots, painting booths, conveyors and application devices (e.g. print heads or atomizers).Finally, it should be mentioned that the invention also comprises a corresponding operating method, wherein the individual method steps of the operating method according to the invention already result from the above description of the coating agent supply according to the invention, so that a separate description of the operating method according to the invention can be dispensed with.Other advantageous developments of the invention are characterized in the dependent claims or are explained in more detail below together with the description of the preferred exemplary embodiments of the invention on the basis of the figures.Brief Description of the DrawingsFIG. 1 shows a schematic illustration of a painting facility according to the invention. FIG. 2 shows details of the paint supply of the paint shop from FIG. 1. FIG. 3 shows a modification of FIGS. 1 and 2. FIG. 4 shows a flow chart for illustrating the operating method according to the invention. FIG. 5 shows a schematic illustration of a paint supply according to the invention. FIG. 6 shows a modification of FIG. 5. FIG. 7 shows a perspective view of a return line with a capacitive sensor for measuring the paint current through the return line. FIG. 8 shows a modification of FIGS. 2 and 3.Detailed Description of the DrawingsFIG. 1 shows a schematic representation of a painting facility for painting motor vehicle body components 1, as is largely known from the earlier German patent application DE 10 2023 102 825.1, so that the content of this earlier patent application is fully incorporated into the following description.The motor vehicle body components 1 to be painted are conveyed along a painting line through a painting booth in which four painting robots 2- 5 are arranged on opposite sides of the painting line, each of which carries a rotary atomizer as an application device, it also being possible alternatively to use other types of application devices (e.g. print heads). On the individual painting robots 2- 5, there is in each case one pig target module 6- 9, wherein the individual pig target modules 6- 9 are connected to a pig source module 14 via pigpable coating agent lines 10- 13. The pig source module 14 is located at a transfer point 15 of a coating agent supply device, which is only schematically shown here and provides the paint to be applied. At the transfer point 15 there is also a valve arrangement 16 which can select the paint from one of a plurality of non-piggable coating agent lines 17 (central channels).A special feature of this exemplary embodiment is that three parallel piggable coating agent lines 10- 13 each run between the pig destination modules 6- 9 and the pig source module 14 at the transfer point 15, so that three different lacquers can be provided at the pig destination modules 6- 9.A further special feature of this exemplary embodiment is the structural design and the mode of operation of the coating agent supply device upstream of the transfer point 15.Thus, the paint to be applied is provided by a total of 15 coating agent storage containers 18, wherein a larger or a smaller number of coating agent storage containers 18 is also possible.The coating agent storage containers 18 each have a coating agent pump 19 which removes the paint from the respective coating agent storage container 18 and conveys it via a non-piggable feed line 20 and a double valve 22 to a pig swelling module 23. From the pig source module 23, a non-piggable return line 21 leads back to the coating agent storage container 18.To avoid misunderstanding, it should be mentioned that each of the 15 coating agent storage containers 18 is assigned a respective pump circuit which leads to a respective pig source module 23. For the sake of simplicity, however, only a single pump circuit is shown in each of the drawings.Furthermore, a return regulator 24 is arranged in the return line 21 of the pump circuit, which regulates the paint pressure at the pig source module 23 to a predefined value.The double valve 22 can selectively forward the paint supplied via the supply line 20 to the pig source module 23 or via a return line 25 to a return line 26.From the pig source module 23, a piggable coating agent line 27 leads through a distribution station 28 to a pig destination module 29, wherein the pig destination module 29 is mechanically connected to the pig source module 23.A connecting line 30 also goes from the pig destination module 29 to the pig source module 23, wherein the connecting line 30 is not piggable. The piggable coating agent line 27 between the pig source module 23 and the pig target module 29 thus forms a color mixing space circuit together with the connecting line 30.This enables a paint circulation comprising both the pump circuit and the paint mixing space circuit. The paint is then removed from the coating agent storage container 18 and flows via the feed line 20 and the double valve 22 into the pig swelling module 23, from where the paint then flows further via the piglable coating agent line 27 through the distribution station 28 to the pig destination module 29, from the pig destination module 29 the paint then flows through the connecting line 30 to the pig swelling module 23 and from there back via the return line 21 to the coating agent storage container 18.Furthermore, a double pig sensor 30 is provided which can detect when a pig passes the double pig sensor 30 in the piggable coating agent line 27. On the one hand, the double pig sensor 30 can thus detect whether a pig 32 enters the pig source module 23 or exits the pig source module 23. On the other hand, however, the double pig sensor 32 can also detect whether a pig 32 is moving into the pig target module 29 or leaves the pig target module 29.To avoid misunderstanding, it should be mentioned that each of the coating agent storage containers 18 is assigned not only a respective pump circuit, but also a respective ink mixing chamber circuit. However, only a single color mixing space circle is shown in the drawings for simplicity.With regard to the further details and the mode of operation of this painting installation, reference is also made to German patent application DE 10 2023 102 825.1, the content of which is fully incorporated into the present description.A particular feature of this embodiment is, compared with the aforementioned earlier patent application, that a paint stop valve 33 is arranged in the return line 25, which self-medium-actuated opens and closes, respectively. This means that the switching state of the ink stop valve 33 depends on the medium present on the inlet side in the return line 25. When filling the pump circuit with the feed line 20 and the return line 21, initially only air is forced out of the pump circuit via the return line 25, wherein the ink stop valve 33 automatically opens. After the pump circuit has been completely filled, paint is then finally forced out via the return line 25, which then leads to the automatic closing of the paint stop valve 33 in the return line 25. This ensures that not unnecessarily much paint is discarded into the return line 26 when the pump circuit is being filled.In addition, the non-piggable coating agent lines 17 ("central channel") pass through the pig source module 14 and are connected to a further pig source module 14' which can feed further pig destination modules, which are not shown for the sake of simplicity. The division into the two connected pig source modules 14, 14' is useful if numerous pig destination modules 6- 9 are to be supplied. In this exemplary embodiment, each of the two pig source modules 14, 14' can then supply three pig destination modules 6- 9, respectively. If the number of pig target modules 6- 9 is larger, further such pig source modules could then be flanged on.In this case, a return line 34 also branches off from the coating agent lines 17 ("central channel") into the return line 26. Also arranged in the return line 34 is a paint stop valve 35 which functions in the same way as the paint stop valve 33; during the filling of the paint system, air is then first forced out into the return line 26 via the return line 34, the paint stop valve 35 then opening automatically. In the further course of the filling process, paint is then finally forced out into the return line 26 via the return line 34, which then leads to automatic closing of the paint stop valve 35. The ink stop valve 35 thus also ensures that not unnecessarily much paint is discarded into the return line 26 when filling the paint system.FIG. 3 shows a modification of FIG. 2, so that, in order to avoid repetitions, reference is made again to the above description, the same reference numerals being used for corresponding details.A special feature of this exemplary embodiment is that the pig swelling module 23 is not supplied with paint via a pump circuit, but only by a coating agent feed line 36, i.e. without a material circulation.A further special feature of this exemplary embodiment is that a return line 37 leads from the pig source module 23 into the return line 26, wherein a color stop valve 38 is likewise arranged in the return line 37, which is constructed and functions in the same manner as the color stop valves 33, 35 described above.The flow chart according to FIG. 4 is now described below, in which the operating method according to the invention is illustrated.In a first step S 1, a suction pump is first switched on in order to suck paint from an ink container.In a step S 2, the paint is then pumped from the paint container by the suction pump into a pump circuit in order to fill the pump circuit.In a step S 3, the paint current is then measured in a feedback path, namely by means of a feedback sensor, which can be a capacitive sensor, for example.In a step S 4, it is then checked whether a paint flow takes place in the recirculation. If this is not the case, this indicates that the pump circuit is not yet completely filled with the paint, so that the method continues with step S 2, i.e. the suction pump remains switched on.Otherwise, this indicates that the pump circuit has already been completely filled with the paint and the suction pump is switched off in a step S 5. This disconnection of the suction pump ensures that when filling the pump circuit, paint does not have to be discarded unnecessarily into the return.FIG. 5 shows a schematic illustration of a paint supply according to the invention with a paint reservoir 39, a paint pump 40 and a pump circuit 41, which is filled with paint by the paint pump 40. In addition, the paint supply has a return line 42, into which excess paint can be discharged via a return line 43 when the pump circuit 41 is being filled. The paint flow of the excess paint through the return line 43 can be measured by a capacitive sensor 44, wherein the capacitive sensor 44 reports the paint flow to a controller 45. The controller 45 then switches off the paint pump 40 when the capacitive sensor 44 detects that paint is being discharged into the return line 42 through the return line 43, since this indicates that the pump circuit 41 is already completely filled with paint.FIG. 6 shows a modification of FIG. 5, so that, in order to avoid repetitions, reference is first made to the above description, the same reference numerals being used for corresponding details.A special feature of this exemplary embodiment is that the controller 45 does not shut off the paint pump 40 upon detection of the beginning of the paint flow into the return line 42, but rather closes a shut-off valve 46 which is arranged in the return line 43. This also prevents an unnecessarily large amount of paint from being discarded into the return line 42 when the pump circuit 41 is being filled.It should be mentioned here that the two exemplary embodiments described above according to FIGS. 5 and 6 can also be combined with one another. The control 45 then takes two actions when detecting the beginning of the paint flow into the return 42. On the one hand, the controller 45 then switches off the paint pump 40. On the other hand, the controller 45 then closes the shut-off valve 46, which is arranged in the return line 43.FIG. 7 shows a perspective view of the return line 43 from FIGS. 5 and 6 with the capacitive sensor 44, which is fastened on the outer wall of the return line 43 by means of two clamping straps 47, 48.FIG. 8 shows a modification of the exemplary embodiment according to FIGS. 2 and 3, so that reference is made to the above description to avoid repetitions, the same reference numerals being used for corresponding details.A special feature of this exemplary embodiment is that the coating agent storage container 18 is connected to the coating agent pump 19 via a non-piggable paint mixing space circuit 49 with the distributor station 28.On the one hand, the non-piggable ink mixing space circuit 49 has a feed line 50 which leads from the coating agent pump 19 to the distributor station 28.On the other hand, the non-piggable ink mixing circuit 49 comprises a return line 51 which leads from the distribution station 28 back into the ink container 18.The invention is not limited to the preferred embodiments described above. Rather, a large number of variants and modifications are possible, which likewise make use of the inventive concept and therefore fall within the scope of protection. In particular, the invention also claims protection for the subject matter and the features of the subclaims independently of the claims respectively referred to and in particular also without the features of the main claim. Thus, the features of the subclaims can also be realized without the concretization of the coating agent system to be filled, according to which a pump circuit or a central channel is involved. The technical teaching of the subclaims can therefore also be realized in general with any coating system which is intended to be filled with a coating agent. The invention thus comprises various aspects of the invention which enjoy protection independently of one another.Advantages of the InventionThe invention offers in particular the following advantages:• The invention makes it possible for the paint losses during filling of the paint system (e.g. pump circuit, central duct) to be independent of paint viscosity, hose lengths / central duct lengths and of the intake behavior of the material pump.• The paint consumption during filling of the paint system is thus always constant and paint is not wasted unnecessarily. Thus, the differences in the amount of paint discarded into the recirculation can be up to 0.5 liter to 2 liters in the prior art, which can be avoided by the invention.• Moreover, the disposal costs for the discarded paint are also reduced, since the recycling is charged with less paint material which would otherwise have to be disposed of.• Finally, the material pump can be operated at lower suction pressures, which is associated with lower wear and longer life.List of reference characters1 Motor vehicle body component 2- 5 Painting robot 6- 9 Pig target modules 10- 13 Coating agent lines (piggable) between the pig source module and the pig target modules 14 Pig source module at the transfer point 14' Pig source module 15 Transfer point 16 Valve arrangement at the transfer point 17 Non-piggable coating agent lines of the pump circuit (central channels) 18 Coating agent storage container ("supply container") 19 Coating agent pump at the coating agent storage container 20 Non-piggable feed line of the pump circuit 21 Non-piggable return line of the pump circuit 22 Dual valve in the feed line of the pump circuit 23 Pig source module 24 Return regulator in the return line of the pump circuit 25 Return line from the dual valve into the return 26 Return 27 Piggable coating agent line between pig source module and pig target module (paint mixing space circle) 28 Distribution station in the paint mixing space circle 29 Pig target module 30 Connecting line between pig source module and pig target module (paint mixing space circle) 31 Double pig sensor in the paint mixing space circle 32 Pig 33 Paint stop valve 34 Return line 35 Paint stop valve 36 Coating agent supply line 37 Return line 38 Paint stop valve 39 Paint reservoir 40 Paint pump 41 Pump circle 42 Return line 43 Return line 44 Capacitive sensor 45 Controller 46 Controllable shut-off valve 47 Clamping band for fastening the capacitive sensor on the return line 48 Clamping band for fastening the capacitive sensor on the return line 49 Paint mixing space circle 50 Supply line of the paint mixing space circle 51 RETURN LINE OF THE COLOR MIXING SPACE CIRCUITReferences included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedDE 10 2023 102 825.1 [0011, 0022, 0023, 0026, 0029, 0031, 0042, 0056]DE 10 2009 020 064 A1

[0015]

Claims

Coating agent supply for supplying a coating system for coating components (1) with a coating agent, in particular for supplying a coating system for coating motor vehicle body components (1) with a paint, having a) a coating agent source (18; 39) for supplying the coating agent, in particular as a coating agent storage container (18; 39), to a coating agent system (17; 18-23; 27-30; 49) which is filled with the coating agent during operation, namely with b1) a non-piggable ink mixing space circuit (49), and / or b2) a piggable ink mixing space circuit (27-30) and a non-piggable pump circuit (18, 19, 22, 25, 26, 33, 36, 37, 38), and / or b2) a central channel (17) of a pig system, wherein the central channel (17) can be connected optionally to one of a plurality of pig lines, c) a coating agent pump (19; 40) for conveying the coating agent from the coating agent source (18; 39) and for filling the coating agent system with the coating agent, and d) a coating agent recirculation (26; 42) for receiving coating agent residues and / or rinsing agent residues from preceding processes during filling of the coating agent system (17; 18-23; 27-30; 49) with the coating agent, characterized by e) a return sensor (33, 35, 38; 44) for detecting an beginning of a coating agent flow of the coating agent into the coating agent return (26; 42) when filling the coating agent system (17; 18-23; 27-30; 49).Coating agent supply according to claim 1, characterised in that a) that the return sensor (33, 35, 38) is part of a self-medium-operated shut-off valve (33, 35, 38), wherein the shut-off valve (33, 35, 38) is controlled by the coating agent applied to the shut-off valve (33, 35, 38), b) that the self-medium-operated shut-off valve (33, 35, 38) either releases or blocks the coating agent flow into the coating agent return (26), c) that the return sensor (33, 35, 38) opens the shut-off valve (33, 35, 38) as long as the coating agent system (17; 18-23; 27-30) is not yet filled with the coating agent and the coating agent therefore does not yet flow into the coating agent return (26), and d) that the return sensor (33, 35, 38; 44) closes the shut-off valve (33, 35, 38) as soon as the coating agent system (17; 18-23; 27-30) is filled with the coating agent and the coating agent therefore flows into the coating agent recirculation line (26).Coating agent supply according to claim 2, characterised in that the self-medium-actuated shut-off valve (33, 35, 38) can also open at an operating pressure of at least 10 bar, 15 bar or 20 bar.The coating agent supply according to claim 1, characterized in that a) the return sensor (44) is a capacitive sensor, or b) the return sensor (44) is an optical sensor, in particular with a light barrier for detecting the coating agent flow of the coating agent into the coating agent return (42), or c) the sensor operates purely mechanically and / or is a component of an intrinsic medium-actuated shut-off valve (33, 35, 38).Coating agent supply according to one of the preceding claims, characterized in that a controller (45) is provided, in particular a programmable logic controller (45), b) that the controller (45) is connected on the input side to the recirculation sensor (44) in order to be able to detect the beginning coating agent flow of the coating agent into the coating agent recirculation (42) when the coating agent system (41) is being filled, and c) that the controller (45) stops the coating agent pump (40) when the beginning coating agent flow of the coating agent into the coating agent recirculation (42) is detected, and / or c2) closes a controllable shut-off valve (46) which either releases or blocks the coating agent flow into the coating agent recirculation (42).The coating agent supply according to any one of the preceding claims, characterized in that the coating agent system (17; 18-23; 27-30) to be filled has a non-piggable pump circuit (18-23) with the following components, in particular in a paint mixing chamber of the coating plant: a) the coating agent source (18), b) the coating agent pump (19), c) a first pigging station (23), d) a non-piggable feed line (20) from the coating agent source (18; ) via the coating agent pump (19) to the first pigging station (23), and e) a non-piggable return line (21) from the first pigging station (23) back to the coating agent source (18).Coating agent supply according to claim 6, characterised in that the coating agent return (26) branches off from the feed line (20) of the non-piggable pump circuit (18-23), in particular at a double valve (22) in the feed line (20).The coating agent supply according to any one of the preceding claims, characterized in that the coating agent system (27-30) to be filled has a pump circuit with the following components: a) a first pigging station (23), which is fed on the input side with the coating agent from the coating agent source (18) via a coating agent feed line (20; 36), a1) wherein the first pigging station (23) is preferably arranged within a paint mixing chamber of the coating plant, a2) wherein the coating agent feed line (20; 36) to the first pigging station (23) is preferably not piglable, a3) wherein the coating agent feed line (20; 36) to the first pigging station is optionally the feed line (20) of the non-pigging pump circuit (18-23), b) of a second pigging station (29), wherein the second pigging station (29) is preferably arranged outside the ink mixing space of the coating plant, c) of a pigging feed line from the first pigging station (23) to the second pigging station (29), and d) of a pigging return line from the second pigging station to the first pigging station.The coating agent supply according to claim 8, characterized in that a) the coating agent recirculation line (26) branches off from the paint mixing space circuit (27-30) at the first pig station (23), and / or b) the coating agent recirculation line (26) branches off from the coating agent supply line (20; 36) to the first pig station (23), in particular at a two-way valve (22) in the coating agent supply line (20; 36) to the first pig station (23).The coating agent supply according to claim 8 or 9, characterized in that the coating agent system (17; 18-23; 27-30) to be filled has the following components: a) a third pig station (14, 14'), in particular outside the ink mixing space, at a transfer point (15) for supplying at least one applicator in a coating booth, b) at least one non-pigpable central channel (17) for connecting the third pig station (14, 14') to the second pig station, c) a fourth pig station (6-9), in particular at a removal point in the coating booth, and d) a pig line (10-13), which connects the third pig station (14, 14') to the fourth pig station (6-9).Coating agent supply according to claim 10, characterised in that the coating agent return (26) branches off from the central channel (17), in particular at the third pig station (14, 14').Coating agent supply according to claim 10 or 11, characterised in that a) a plurality of piggable paint mixing space circuits are provided in order to be able to supply a plurality of different coating agents, b) that the piggable paint mixing space circuits are fed on the input side from a respective coating agent source, and c) that the molgable paint mixing space circuits are connected on the output side to a distributor station (28), which selects one of the piggable paint mixing space circuits and connects it to the third pigging station (14, 14).The coating agent supply according to any one of the preceding claims, characterized in that a) the coating agent source (18; 39) has a coating agent storage container (18; 39), in particular with a capacity of at least 1 L, 2 L, 5 L, 10 L, 20 L, 50 L, 500 L or 1000 L and / or b) that the coating agent pump (19; 40) is a suction pump, and / or c) that the coating agent pump (19; 40) is pneumatically or electrically driven, and / or d) that the components (1) to be coated are motor vehicle body components (1), and / or e) that the coating agent is a paint, and / or f) that the central channel (17) is relatively short with a length of at most 5 m, 1 m, 50 cm, 24 cm, 15 cm, 10 cm or 5 cm, and / or g) that the central channel (17) is not piglable, and / or h) that the first pig station (23) and the second pig station (29) have a relatively large distance of at least 2m, 5m, 10m, 20m, 50m, 100m or 150m from one another, and / or i) that the applicator is a print head or an atomizer, in particular a rotary atomizer, and / or j) that the number of coating agent storage containers (18) is greater than two, three, four or five.Coating plant for coating the components (1) with the coating agent, in particular a paint plant for painting the motor vehicle body components with the paint, with the coating agent supply according to one of the preceding claims and preferably with at least one of the following components: a) an applicator for applying the coating agent, in particular a print head or an atomizer, b) a paint robot (2-5) for guiding the applicator, c) a paint booth in which the paint robot with the applicator is arranged, d) a conveyor for conveying the components (1) to be painted through the paint plant.Operating method for a coating agent supply, in particular for a coating agent supply according to one of Claims 1 to 13, in particular in a coating plant according to Claim 14, having the following steps: a) provision of the coating agent by a coating agent source (18; 39), in particular by a coating agent storage container (18; 39), b) filling a coating agent system with the coating agent by pumping the coating agent by a coating agent pump (19; 40) from the coating agent source (18; 39) to the coating agent system (17; 18-23; 27-30) to be filled, wherein the coating agent system (17; 18-23 to be filled is pumped; 27-30), b1) has a piggable or non-piggable color mixing space circle or b2) has a central channel (17) of a pig system, wherein the central channel (17) is optionally connected to one of a plurality of pig lines, and c) discarding excess coating agent, in particular paint-solvent mixture, when filling the coating agent system into a coating agent recirculation (26; 42), characterized bythe following step: d) detecting an beginning coating agent flow of the coating agent into the coating agent recirculation (26; 42) by means of a recirculation sensor (44).Operating method according to Claim 15, characterized bythe following steps: a) switching off the coating agent pump (19; 40) if the recirculation sensor (33, 35, 38; 44) detects the beginning of the coating agent flow of the excess coating agent into the coating agent recirculation (26; 42) during filling of the coating agent system, and / or b) blocking off the coating agent flow into the coating agent recirculation (26; 42) by means of a shut-off valve (33, 35, 38; 46) if the recirculation sensor (33, 35, 38; 44) detects the beginning of the coating agent flow of the excess coating agent into the coating agent recirculation (26; 42) during filling of the coating agent system.

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