Coating agent supply and associated operating method

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), having: - 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). The invention also relates to a corresponding operating method.

Description

[0001] DESCRIPTION

[0002] Coating agent supply and associated operating procedures

[0003] Technical field of the invention

[0004] 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).

[0005] Background of the invention

[0006] In modern painting systems for painting motor vehicle body components, the paint to be applied is usually stored in large-volume paint containers. The paint is then sucked from the respective paint container by a paint pump and conveyed via a pump circuit and other piping systems to an application device (e.g. atomizer, print head). Before the actual painting process can begin, the pump circuit must be filled with paint. This is done in a so-called loading cycle that is time-controlled and has a predetermined filling time. During this loading cycle with the predetermined filling time, the paint pump pumps the paint from the paint container into the pump circuit, thereby filling the pump circuit with paint. To ensure a paint change without any paint carryover, the paint and any residual rinsing agent from previous process steps are then discarded into a recirculation system during this filling process.The actual filling time required depends on the paint viscosity, the hose length, and the suction behavior of the paint pump. The filling time must therefore be selected to be long enough to ensure that the pump circuit is completely filled with paint within the filling time, even with the highest paint viscosity, the longest hose length, and the poorest suction behavior of the paint pump. However, this leads to a greater or lesser amount of paint being discarded into the return line in practice. This is particularly true when using low-viscosity paints, which are easier to suck in and pump, so that an unnecessary amount of paint is discarded into the return line because the filling time is not adjusted to the actual circumstances (e.g. paint viscosity, hose length, suction behavior of the paint pump).The disadvantage of the known paint supplies in painting systems is the paint losses when filling the pump circuit and the associated effort for disposing of the discarded paint quantity.

[0007] For the technical background of the invention, reference should also be made to DE 10 2006 002 389 A1, US 2009 / 0134241 A1 and DE 10 2009 020 064 A1.

[0008] The invention is therefore based on the object of reducing paint losses when filling the pump circuit of a painting system.

[0009] This object is achieved by a coating agent supply according to the invention or by an associated operating method according to the independent claims.

[0010] The coating agent supply system according to the invention initially comprises, in accordance with the prior art, at least one coating agent source for providing the coating agent. The coating agent source is preferably a large-volume coating agent storage container, such as those known from painting systems for painting motor vehicle body components. Alternatively, however, the coating agent source can be a ring line or another coating agent source.

[0011] It should be noted that the invention is not limited to paints with regard to the coating agent, but can in principle also be implemented with other types of coating agents, such as insulating materials, sealants or adhesives, to name just a few examples.

[0012] Furthermore, the coating agent supply according to the invention is not limited to the preferred use in a painting system for painting motor vehicle body components.

[0013] In addition to the coating agent source mentioned above, the coating agent supply according to the invention, in accordance with the prior art, comprises a coating agent system which is to be filled with the coating agent during operation.

[0014] For example, the coating system to be filled may be a pump circuit, as already mentioned at the beginning of the state of the art. The pump circuit typically includes the volume of the coating pump to be filled, the suction and pressure hoses, and the associated valve stations.

[0015] However, within the scope of the invention, it is also possible for the coating system to be filled to be a central channel of a pigging system, wherein the central channel can be selectively connected to one of several pigging 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 to be fully attributed to the present description of the invention.

[0016] Furthermore, the coating agent supply according to the invention, in accordance with the prior art, also comprises a coating agent pump which conveys 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).

[0017] Furthermore, the coating agent supply according to the invention also has, in accordance with the prior art described at the outset, a coating agent return in order to be able to discharge excess coating agent into the coating agent return when filling the coating agent system (e.g. pump circuit, central channel).

[0018] The coating agent supply according to the invention is characterized by a return sensor for detecting the beginning of a coating agent flow into the coating agent return line when filling the coating agent system (e.g., pump circuit, central channel). Detecting the beginning of a coating agent flow into the coating agent return line when filling the coating agent system offers the possibility of terminating the filling process immediately after filling the coating agent system, so that the amount of coating agent discarded into the coating agent return line can be minimized. In one variant of the invention, the return sensor is part of a self-medium-operated shut-off valve ("paint stop valve"), whereby 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 it opens the flow path into the coating agent return line as long as the coating agent system (e.g. pump circuit, central channel) is not yet filled with the coating agent and the coating agent is therefore not yet flowing into the coating agent return 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 is therefore flowing into the coating agent return line. The self-medium-actuated shut-off valve is therefore automatically controlled by the coating agent flowing into the coating agent return line. The return sensor integrated into the shut-off valve preferably operates purely mechanically. Such self-medium-actuated shut-off valves are known per se from the prior art and therefore need not be described in more detail.However, examples of such shut-off valves are described in the German patent application DE 10 2009 020 064 A1, so that the content of this earlier patent application is to be fully attributed to the present description with regard to the structural design and the functioning of the self-medium-operated shut-off valve.

[0019] It should be noted that the medium-operated shut-off valve should be designed so that it can open even at a system pressure of 20 bar, as may be required in paint systems. The shut-off valve (paint stop valve) can typically assume an open, a closed, or a center position, whereby the open and closed valve positions can be actively controlled. The shut-off valve (paint stop valve) closes automatically as soon as medium arrives at it. The closing function occurs within a certain viscosity range, as is the case with a solvent-paint mixture, for example. A safety function ensures that a small amount of the medium is "over-pressurized." The shut-off valve (paint stop valve), which was closed shortly before, is actively opened again briefly – against the system pressure, which can be a maximum of 20 bar. This ensures that truly pure paint reaches the paint stop valve.During a filling process, a solvent-paint mixture is first forced into the return line, which automatically closes the shut-off valve (paint stop valve), even though the paint system is not yet completely filled with paint, but is still partially filled with solvent. Briefly opening the shut-off valve (paint stop valve) then allows the remaining solvent to escape, so that the paint system being filled is then filled exclusively with 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 so that it can open even at a system pressure of 20 bar.

[0020] Alternatively, however, it is possible for the return sensor to be separate from the shut-off valve. For example, the return sensor can be a capacitive sensor that uses a capacitive measurement to detect whether coating agent is flowing through a return line into the coating agent return line. For example, such a capacitive sensor can be attached to the outer wall of the return line, for example, using one or more clamping straps.

[0021] However, the return sensor can alternatively also be an optical sensor, which can, for example, have a light barrier to detect the coating agent flow of the coating agent into the coating agent return.

[0022] However, with regard to the functionality of the feedback sensor, the invention is not limited to the two examples mentioned above (capacitive sensor, optical sensor), but can also be implemented with other sensor types. For example, purely mechanical sensors, ultrasonic sensors, or magnetic-inductive flow meters (MIDs) can also be used as feedback sensors within the scope of the invention, to name just a few examples.

[0023] In the above-described variant of the invention with a separate return sensor (e.g., capacitive or optical sensor), a controller (e.g., PLC: programmable logic controller) is preferably also provided, which is connected to the return sensor on the input side in order to be able to detect when, during filling of the coating system, coating agent flows into the coating agent return line, which indicates that the coating agent system to be filled is completely full. The controller can then take various measures to prevent an unnecessary amount of coating agent from being discarded into the coating agent return line. One possible response of the controller is to stop the coating agent pump, thereby terminating the filling process.Another possible control response is for the control to close a controllable shutoff valve, which either allows or blocks the flow of coating agent into the coating agent return line. These two control responses can also be combined, meaning the control can stop the coating agent pump and also close the shutoff valve when the return sensor detects the beginning of the coating agent flow into the return line.

[0024] In a preferred embodiment of the invention, the coating system to be filled has a non-piggable pump circuit, which is preferably arranged in a paint mixing room of a painting system and has the following components:

[0025] • The coating agent source (e.g. paint storage container),

[0026] • the coating agent pump,

[0027] • a first pig station (“pig source station”),

[0028] • a non-piggable feed line from the coating agent source via the coating agent pump to the first pigging station, and

[0029] • a non-piggable return line from the first pigging station back to the coating agent source.

[0030] Such a non-piggable pump circuit is known per se from the German patent application DE 10 2023 102 825.1 already mentioned above, so that the content of this earlier patent application is to be fully attributed to the present description.

[0031] In this case, it is possible for several different coating agent sources (e.g., paint storage containers) for different colored coating agents to be provided in the paint mixing room of the painting system. Each of these coating agent sources can then be equipped with a separate, non-piggable pump circuit to convey the respective coating agent to the first pigging station. The first pigging station ("pig source station") can then have a valve unit to select one of the supplied coating agents. This is also known per se from the aforementioned 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.

[0032] The above-mentioned coating agent return for the return of excess coating agent when filling the pump circuit then preferably branches off from the supply line of the non-piggable pump circuit, for example at a double valve in the supply line to the first pigging station ("pig source station").

[0033] Furthermore, within the scope of the invention, it is possible for the coating system to be filled to have a coating circuit, in particular a paint mixing chamber circuit or a pump and paint mixing chamber circuit, with the following components:

[0034] • A first pigging station ("pig source station"), which is fed with the coating agent from the coating agent source via a coating agent supply line from the coating agent pump, wherein the first pigging station is preferably arranged within a paint mixing room of the coating system,

[0035] • a second pigging station (“pig target station”), wherein the second pigging station is preferably located outside the paint mixing room of the coating system,

[0036] • a piggable supply line from the first pigging station to the second pigging station, and

[0037] • a piggable return line from the second pigging station to the first pigging station. Such a coating agent circuit is also known from the aforementioned German patent application DE 10 2023 102 825.1, so the content of this earlier patent application is fully incorporated into the present description.

[0038] It was mentioned above that the piggable coating agent circuit is supplied with the coating agent from a coating agent supply line. If the coating agent circuit includes a piggable paint mixing chamber circuit, the non-piggable pump circuit described above can take over the function of the coating agent supply line. The non-piggable pump circuit has a feed line and a return line, thus enabling material circulation. However, it is also possible for the paint mixing chamber circuit to be non-piggable and to be supplied directly from the coating agent source without a separate pump circuit.

[0039] In the coating agent circuit described above, the coating agent return line with the associated return sensor can branch off from various locations. For example, the coating agent return line can branch off from the pump circuit at the first pigging station ("pig source station"). Alternatively or additionally, it is also possible for the coating agent return line to branch off from the coating agent supply line to the first pigging station, in particular at a dual valve in the coating agent supply line to the first pigging station.

[0040] In the non-piggable pump circuit described above, the first pigging station (pig source station) is preferably located in the paint mixing room of the paint shop, while the second pigging station (pig destination station) is preferably located outside the paint mixing room, for example, at a transfer point for supplying multiple paint booths. A third pigging station (pig source station) is then preferably also arranged at the transfer point, which is connected to the second pigging station via a non-piggable central channel. The third pigging station, in turn, is connected via a pigging line to a fourth pigging station (pig destination station), which is preferably located at a removal point in a coating booth. This arrangement is fundamentally known from the German patent application DE 10 2023 102 825 described above.1, so that the content of this earlier patent application is to be fully incorporated into the present description.

[0041] In this design with a total of four pigging stations, a coating agent return line with an associated return sensor can also branch off from the central channel between the second pigging station (pig target station) and the third pigging station (pig source station).

[0042] In this case, several coating agent circuits can be provided to supply several different coating agents. The coating agent circuits are then each fed on the inlet side from a coating agent source. On the outlet side, the coating agent circuits are connected to a distribution station, which selects one of the coating agent circuits and connects it to the third pigging station. This arrangement is also known in principle from the German patent application DE 102023 102825.1 described above, so the content of this earlier patent application is fully incorporated into the present description.

[0043] It has already been mentioned above that the coating agent source is preferably a coating agent storage container, 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 detail.

[0044] In the context of the invention, the coating agent pump is preferably a suction pump, which is preferably electrically driven.

[0045] In general, it should also be noted that the components to be coated are preferably motor vehicle body components, with the coating agent then being a paint. However, it has already been mentioned above that the invention is not limited to paints or motor vehicle body components with regard to the coating agent or the components to be coated.

[0046] Furthermore, it should 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.

[0047] The first and second pigging stations, however, can be arranged at a relatively large distance from each other, for example, more than 2m, 5m, 10m, 20m, 50m, 100m, or 150m. This allows the first pigging station (pig source station) to be located in the paint mixing room, while the second pigging station (pig destination station) is located outside the paint mixing room, near the paint booths.

[0048] It should also be noted that the applicator for coating the components is preferably a print head or an atomizer (e.g., a rotary atomizer). These applicator types are known in the art and therefore need not be described in detail.

[0049] Furthermore, it should also be noted that the coating agent supply system according to the invention can comprise multiple 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-piggy-able paint mixing chamber circuit and / or a non-piggy-able pump circuit.

[0050] Above, the coating agent supply according to the invention was described independently of the coating system to be supplied. However, the invention also claims protection for a coating system according to the invention that has the coating agent supply described above. In addition, the coating system according to the invention then contains further components, such as painting robots, painting booths, conveyors, and application devices (e.g., print heads or atomizers).

[0051] 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.

[0052] Other advantageous developments of the invention are characterized in the subclaims or are explained in more detail below together with the description of the preferred embodiments of the invention with reference to the figures.

[0053] Figure 1 shows a schematic representation of a painting system according to the invention.

[0054] Figure 2 shows details of the paint supply of the painting system from Figure 1.

[0055] Figure 3 shows a modification of Figures 1 and 2.

[0056] Figure 4 shows a flow chart to illustrate the operating method according to the invention.

[0057] Figure 5 shows a schematic representation of a paint supply according to the invention.

[0058] Figure 6 shows a modification of Figure 5.

[0059] Figure 7 shows a perspective view of a return line with a capacitive sensor for measuring the paint flow through the return line.

[0060] Figure 8 shows a modification of Figures 2 and 3.

[0061] Detailed description of the drawings

[0062] Figure 1 shows a schematic representation of a painting system 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 to be attributed in full to 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, although other types of application devices (e.g. print heads) can also be used alternatively. A pig target module 6-9 is each located on the individual painting robots 2-5, whereby the individual pig target modules 6-9 are connected to a pig source module 14 via piggable coating agent lines 10-13.The pigging source module 14 is located at a transfer point 15 of a coating agent supply system, shown only schematically here, which supplies the paint to be applied. Also located at the transfer point 15 is a valve assembly 16 that can select the paint from one of several non-piggable coating agent lines 17 (central channels).

[0063] A special feature of this embodiment is that three parallel piggable coating agent lines 10-13 run between the pig target modules 6-9 and the pig source module 14 at the transfer point 15, so that three different paints can be provided to the pig target modules 6-9.

[0064] A further special feature of this embodiment is the structural design and functioning of the coating agent supply device upstream of the transfer point 15.

[0065] The paint to be applied is provided by a total of 15 coating agent storage containers 18, although a larger or smaller number of coating agent storage containers 18 is also possible.

[0066] The coating agent storage tanks 18 each have a coating agent pump 19, which removes the paint from the respective coating agent storage tank 18 and conveys it via a non-piggy supply line 20 and a dual valve 22 to a pig source module 23. A non-piggy return line 21 leads from the pig source module 23 back to the coating agent storage tank 18. The supply line 20 and the return line 21 thus form a pump circuit that is non-piggy and enables material circulation in the pump circuit. To avoid misunderstandings, it should be mentioned that each of the 15 coating agent storage tanks 18 is assigned a pump circuit, each of which leads to a pig source module 23. For simplicity, however, only a single pump circuit is shown in the drawings.

[0067] In addition, a return flow 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 predetermined value.

[0068] The dual valve 22 can forward the paint supplied via the feed line 20 either to the pig source module 23 or via a return line 25 into a return line 26.

[0069] From the pig source module 23, a piggable coating agent line 27 leads through a distribution station 28 to a pig target module 29, wherein the pig target module 29 is mechanically connected to the pig source module 23.

[0070] A connecting line 30 also runs from the pig target module 29 to the pig source module 23, whereby 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, together with the connecting line 30, forms a paint mixing chamber circuit.

[0071] This enables paint circulation that encompasses both the pump circuit and the paint mixing chamber circuit. The paint is then drawn from the coating agent reservoir 18 and flows via the feed line 20 and the dual valve 22 into the pig source module 23. From there, the paint flows further via the piggable coating agent line 27 through the distribution station 28 to the pig target module 29. From the pig target module 29, the paint then flows through the connecting line 30 to the pig source module 23 and from there back to the coating agent reservoir 18 via the return line 21.

[0072] In addition, a double pig sensor 30 is provided, which can detect when a pig passes through the double pig sensor 30 in the piggable coating agent line 27. On the one hand, the double pig sensor 30 can therefore detect whether a pig 32 is moving into the pig source module 23 or out of the pig source module 23. On the other hand, the double pig sensor 32 can also detect whether a pig 32 is moving into the pig target module 29 or leaving the pig target module 29. To avoid misunderstandings, it should be mentioned that each of the coating agent storage containers 18 is assigned not only a pump circuit but also a paint mixing chamber circuit. However, for the sake of simplicity, only a single paint mixing chamber circuit is shown in the drawings.

[0073] For further details and the functioning of this painting system, reference is also made to the German patent application DE 10 2023 102 825.1, the content of which is fully incorporated into the present description.

[0074] A special feature of this embodiment compared to the aforementioned earlier patent application is that a paint stop valve 33 is arranged in the return line 25, which opens and closes under its own medium. This means that the switching state of the paint stop valve 33 depends on the medium present in the inlet side of the return line 25. When filling the pump circuit via the feed line 20 and the return line 21, initially only air is forced out of the pump circuit via the return line 25, whereby the paint stop valve 33 opens automatically. After the pump circuit has been completely filled, paint is 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 when filling the pump circuit, an unnecessary amount of paint is not discarded into the return line 26.

[0075] In addition, the non-piggable coating agent lines 17 ("central channel") pass through the pig source module 14 and are connected to another pig source module 14', which can supply additional pig target modules, which are not shown for simplification. The division into the two interconnected pig source modules 14, 14' is useful if numerous pig target modules 6-9 are to be supplied. In this embodiment, each of the two pig source modules 14, 14' can then supply three pig target modules 6-9. With a larger number of pig target modules 6-9, additional such pig source modules could then be flanged on.

[0076] Here, a return line 34 also branches off from the coating agent lines 17 ("central channel") into the return line 26. A paint stop valve 35 is also arranged in the return line 34, which functions in the same way as the paint stop valve 33. When filling the paint system, air is first forced out via the return line 34 into the return line 26, whereby the paint stop valve 35 then opens automatically. As the filling process continues, paint is finally forced out via the return line 34 into the return line 26, which then leads to the automatic closing of the paint stop valve 35. The paint stop valve 35 thus also ensures that an unnecessary amount of paint is not discarded into the return line 26 when filling the paint system.

[0077] Figure 3 shows a modification of Figure 2, so that in order to avoid repetition, reference is again made to the above description, the same reference numerals being used for corresponding details.

[0078] A special feature of this embodiment is that the pig source module 23 is not supplied with paint via a pump circuit, but only via a coating agent supply line 36, ie without material circulation.

[0079] A further special feature of this embodiment is that a return line 37 leads from the pig source module 23 into the return line 26, wherein a paint stop valve 38 is also arranged in the return line 37, which is constructed and functions in the same way as the paint stop valves 33, 35 described above.

[0080] The flow chart according to Figure 4, in which the operating method according to the invention is shown, is now described below.

[0081] In a first step S1, a suction pump is switched on to suck paint from a paint container.

[0082] In a step S2, the paint is then pumped from the paint container into a pump circuit by the suction pump in order to fill the pump circuit.

[0083] In a step S3, the paint flow is then measured in a feedback loop using a feedback sensor, which can be a capacitive sensor, for example.

[0084] In step S4, a check is then made to determine whether a paint flow is occurring in the return line. If this is not the case, this indicates that the pump circuit is not yet completely filled with paint, so the system continues with step S2, i.e., the suction pump remains switched on. Otherwise, this indicates that the pump circuit is already completely filled with paint, and in step S5, the suction pump is switched off. This switching off of the suction pump ensures that no paint is unnecessarily discarded into the return line when filling the pump circuit.

[0085] Figure 5 shows a schematic representation of a paint supply system according to the invention, comprising a paint reservoir 39, a paint pump 40, and a pump circuit 41 filled with paint by the paint pump 40. Furthermore, the paint supply system has a return line 42 into which excess paint can be discharged via a return line 43 when the pump circuit 41 is filled. The paint flow of the excess paint through the return line 43 can be measured by a capacitive sensor 44, which 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, as this indicates that the pump circuit 41 is already completely filled with paint.

[0086] Figure 6 shows a modification of Figure 5, so that in order to avoid repetition, reference is first made to the above description, the same reference numerals being used for corresponding details.

[0087] A special feature of this embodiment is that when the controller 45 detects the beginning of a paint flow into the return line 42, it does not shut off the paint pump 40, but rather closes a shut-off valve 46 located in the return line 43. This also prevents an unnecessary amount of paint from being discarded into the return line 42 when filling the pump circuit 41.

[0088] It should be noted that the two embodiments described above, according to Figures 5 and 6, can also be combined with one another. Upon detecting the beginning of the paint flow into the return line 42, the controller 45 then takes two measures. First, the controller 45 then shuts off the paint pump 40. Second, the controller 45 then closes the shut-off valve 46, which is arranged in the return line 43.

[0089] Figure 7 shows a perspective view of the return line 43 from Figures 5 and 6 with the capacitive sensor 44, which is attached to the outer wall of the return line 43 by means of two clamping bands 47, 48.

[0090] Figure 8 shows a modification of the embodiment according to Figures 2 and 3, so that in order to avoid repetition, reference is made to the above description, the same reference numerals being used for corresponding details.

[0091] A special feature of this embodiment is that the coating agent storage tank 18 with the coating agent pump 19 is connected to the distribution station 28 via a non-piggable paint mixing chamber circuit 49.

[0092] On the one hand, the non-piggyback paint mixing chamber circuit 49 has a feed line 50 which leads from the coating agent pump 19 to the distribution station 28.

[0093] On the other hand, the non-piggable paint mixing chamber circuit 49 comprises a return line 51 which leads from the distribution station 28 back into the paint container 18.

[0094] The invention is not limited to the preferred embodiments described above. Rather, a multitude of variants and modifications are possible which also 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 features of the subclaims independently of the respective claims referred to and in particular even without the features of the main claim. Thus, the features of the subclaims can also be implemented without specifying the coating system to be filled, according to which it is a pump circuit or a central channel. The technical teaching of the subclaims is therefore also generally applicable to any coating system that is to be filled with a coating agent. The invention therefore encompasses various aspects of the invention which are protected independently of one another.

[0095] Advantages of

[0096] The invention offers in particular the following advantages:

[0097] The invention enables paint losses when filling the paint system (e.g., pump circuit, central channel) to be independent of paint viscosity, hose lengths / central channel lengths, and the suction behavior of the material pump. • The paint consumption when filling the paint system is therefore always constant, and no paint is wasted unnecessarily. Thus, the differences in the amount of paint discarded in the recycling system can be up to 0.5 liters to 2 liters in the prior art, which can be avoided by the invention. • Furthermore, the disposal costs for the discarded paint are reduced, since the

[0098] The return process involves less paint material that would otherwise have to be disposed of.

[0099] • Finally, the material pump can be operated with lower suction pressures, which is associated with less wear and a longer service life.

[0100]

[0101] 1 motor vehicle body component

[0102] 2-5 painting robots

[0103] 6-9 pig target modules

[0104] 10-13 Coating agent lines (piggable) between the pig source module and the pig target modules

[0105] 14 Pig source module at the transfer point

[0106] 14' pig source module

[0107] 15 Transfer point

[0108] 16 Valve arrangement at the transfer point

[0109] 17 Non-piggyable coating lines of the pump circuit (central channels)

[0110] 18 coating agent storage containers ("delivery containers")

[0111] 19 Coating agent pump on the coating agent storage tank

[0112] 20 Non-piggable flow line of the pump circuit

[0113] 21 Non-piggable return line of the pump circuit

[0114] 22 Double valve in the flow line of the pump circuit

[0115] 23 Pig source module

[0116] 24 Return flow regulator in the return line of the pump circuit

[0117] 25 Return line from the double valve to the return

[0118] 26 Repatriation

[0119] 27 Piggable coating agent line between pig source module and pig target module

[0120] (color mixing room circle)

[0121] 28 Distribution station in the paint mixing room circuit

[0122] 29 Pig Target Module

[0123] 30 Connection line between the pig source module and the pig target module (paint mixing room circuit)

[0124] 31 Double pig sensor in the paint mixing room circuit

[0125] 32 newts

[0126] 33 Paint stop valve

[0127] 34 Return line

[0128] 35 Paint stop valve

[0129] 36 Coating agent supply line

[0130] 37 Return line 38 Paint stop valve

[0131] 39 paint storage containers

[0132] 40 paint pump

[0133] 41 Pump circuit 42 Return

[0134] 43 Return line

[0135] 44 Capacitive sensor

[0136] 45 Control

[0137] 46 Controllable shut-off valve 47 Clamping band for fastening the capacitive sensor on the return line

[0138] 48 Clamping strap for attaching the capacitive sensor to the return line

[0139] 49 Color mixing room circle

[0140] 50 Supply line of the paint mixing room circuit

[0141] 51 Return line of the paint mixing room circuit

Claims

Claims 1. Coating agent supply for supplying a coating system for coating components (1) with a coating agent, in particular for supplying a painting system for painting motor vehicle body components (1) with a paint, with a) a coating agent source (18; 39) for providing the coating agent, in particular as a coating agent storage container (18; 39), b) a coating agent system (17; 18-23; 27-30; 49), which is filled with the coating agent during operation, namely with b1) a non-piggybackable paint mixing chamber circuit (49), and / or b2) a piggable paint mixing chamber circuit (27-30) and a non-piggybackable pump circuit (18, 19, 22, 25, 26, 33, 36, 37, 38), and / or b3) a central channel (17) of a pigging system, wherein the central channel (17) is optionally connected to one of several 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 return line (26; 42) for receiving coating agent residues and / or rinsing agent residues from previous processes when filling 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 incipient coating agent flow of the coating agent into the coating agent return line (26; 42) when filling the coating agent system (17; 18-23; 27-30; 49).

2. Coating agent supply according to claim 1, characterized in that a) the return sensor (33, 35, 38) is a component 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) 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) 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 return (26).

3. Coating agent supply according to claim 2, characterized in that the self-medium-operated shut-off valve (33, 35, 38) can also open at an operating pressure of at least 10 bar, 15 bar or 20 bar.

4. 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 works purely mechanically and / or is a component of a self-medium-operated shut-off valve (33, 35, 38).

5. Coating agent supply according to one of the preceding claims, characterized in that a) a controller (45) is provided, in particular a programmable logic controller (45), b) the controller (45) is connected on the input side to the return sensor (44) in order to be able to detect the incipient coating agent flow of the coating agent into the coating agent return (42) when the coating agent system (41) is being filled, and c) the controller (45), upon detecting the incipient coating agent flow of the coating agent into the coating agent return (42), c1) stops the coating agent pump (40) and / or c2) closes a controllable shut-off valve (46) which either releases or blocks the coating agent flow into the coating agent return (42).

6. Coating agent supply according to 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 room of the coating system: 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).

7. Coating agent supply according to claim 6, characterized in that the coating agent return line (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).

8. Coating agent supply according to 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 with the coating agent on the inlet side via a coating agent feed line (20; 36) by the coating agent pump (19) from the coating agent source (18), a1) wherein the first pigging station (23) is preferably arranged within a paint mixing room of the coating system, a2) wherein the coating agent feed line (20; 36) to the first pigging station (23) is preferably not piggable, a3) wherein the coating agent feed line (20;36) to the first pigging station is optionally the feed line (20) of the non-piggable pump circuit (18-23), b) a second pigging station (29), wherein the second pigging station (29) is preferably arranged outside the paint mixing room of the coating system, c) a piggable feed line from the first pigging station (23) to the second pigging station (29), and d) a piggable return line from the second pigging station to the first pigging station.; 9. Coating agent supply according to claim 8, characterized in that a) the coating agent return (26) at the first pigging station (23) is Paint mixing room circuit (27-30) branches off, and / or b) that the coating agent return (26) is from the coating agent supply line (20; 36) branches off to the first pigging station (23), in particular at a double valve (22) in the coating agent supply line (20; 36) to the first pigging station (23).

10. Coating agent supply according to claim 8 or 9, characterized in that the coating agent system to be filled (17; 18-23; 27-30) has the following components: a) a third pigging station (14, 14'), in particular outside the paint mixing room at a transfer point (15) for supplying at least one applicator in a coating booth, b) at least one non-piggable central channel (17) for connecting the third pigging station (14, 14') to the second pigging station, c) a fourth pigging station (6-9), in particular at a removal point in the coating booth, and d) a pigging line (10-13) which connects the third pigging station (14, 14') to the fourth pigging station (6-9).

11. Coating agent supply according to claim 10, characterized in that the coating agent return (26) branches off from the central channel (17), in particular at the third pigging station (14, 14').

12. Coating agent supply according to claim 10 or 11, characterized in that a) several piggable paint mixing chamber circuits are provided in order to be able to supply several different coating agents, b) the piggable paint mixing chamber circuits are fed on the input side from a coating agent source each, and c) the piggable paint mixing chamber circuits are connected on the output side to a distribution station (28) which selects one of the piggable paint mixing chamber circuits and connects it to the third pigging station (14, 14).

13. Coating agent supply according to one of the preceding claims, characterized in that a) the coating agent source (18; 39) comprises 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 5m, 1m, 50cm, 24cm, 15cm, 10cm or 5cm, and / or g) that the central channel (17) is not piggable, and / or h) that the first pigging station (23) and the second pigging station (29) have a relatively large distance of at least 2m, 5m, 10m, 20m, 50m, 100m or 150m from each other, 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.

14. Coating system for coating the components (1) with the coating agent, in particular a painting system 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 painting robot (2-5) for guiding the applicator, c) a painting booth in which the painting robot with the applicator is arranged, d) a conveyor for conveying the components (1) to be painted through the painting system.

15. 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 system according to claim 14, with the following steps: a) providing 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 from the coating agent source (18; 39) to the coating agent system (17; 18-23; 27-30) to be filled by a coating agent pump (19; 40), wherein the coating agent system (17; 18-23; 27-30) to be filled bl) has a piggable or non-piggable paint mixing chamber circuit or b2) a central channel (17) of a pigging system, wherein the central channel (17) is selectively connected to one of several pigging lines, and c) discarding excess coating agent, in particular paint-solvent mixture, when filling the coating agent system into a coating agent return line (26; 42), characterized by the following step: d) detecting an incipient coating agent flow of the coating agent into the coating agent return line (26; 42) by means of a return sensor (44).

16. Operating method according to claim 15, characterized by the following steps: a) switching off the coating agent pump (19; 40) when the return sensor (33, 35, 38; 44) detects the beginning of a coating agent flow of the excess coating agent into the coating agent return line (26; 42) when the coating agent system is being filled, and / or b) shutting off the coating agent flow into the coating agent return line (26; 42) by means of a shut-off valve (33, 35, 38; 46) when the return sensor (33, 35, 38; 44) detects the beginning of a coating agent flow of the excess coating agent into the coating agent return line (26; 42) when the coating agent system is being filled.

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