EP4037841A1

EP4037841A1 - Paint-supply system for a coating installation, and associated operating method

Info

Publication number: EP4037841A1
Application number: EP20804510.4A
Authority: EP
Inventors: Alexander RÜGER; Sascha Hermann; Luis JIMENEZ CADENAS; Eduard FRÜHSORGER
Original assignee: Duerr Systems AG
Current assignee: Duerr Systems AG
Priority date: 2019-11-15
Filing date: 2020-11-10
Publication date: 2022-08-10
Also published as: CN114728300A; DE102019130920A1; WO2021094283A1; US11890630B2; US20220401987A1; US20240165648A1; CN114728300B

Abstract

The invention relates to a paint-supply system for a coating installation (for example a painting installation) with a ring line (4) for the circulation of a coating agent (2), a ring-line removal point (10) in the ring line (4) for the removal of the coating agent (2) from the ring line (4), a consumer (8) and a branch line (9), which leads from the ring-line removal point (10) to the consumer (8). The invention provides a device (3, 5, 13) for moving the coating agent (2) alternately forwards and back in the branch line (9), in order to avoid sedimentation of the coating agent (2) in the branch line (9).

Description

DESCRIPTION

Paint supply system for a coating system and the associated operating process

The invention relates to a paint supply system for a coating installation, in particular for a painting installation for painting motor vehicle body components. Furthermore, the invention relates to an operating method for such a paint supply system.

In modern painting systems for painting vehicle body components, the paint is usually fed through ring lines to the consumers (e.g. rotary atomizers), with the paint circulating in the ring lines so that the paint does not settle. The consumers (e.g. rotary atomizers) remove the paint from the ring main at a ring main extraction point via a branch line. The problem here is the fact that the paint does circulate in the ring line, but not in the branch line. So if a consumer (e.g. rotary atomizer) is not used for a longer period of time, the paint is in the associated branch line, which can lead to the paint settling or its viscosity changing in the event of a longer standstill.

A known solution to this problem is to automatically empty the stub lines after a certain period of standstill, which is also referred to as unplugging. The paint in the branch line is disposed of in a return line. However, this known solution to the problem is disadvantageous because it is associated with paint losses and additional effort.

Another conceivable solution to this problem is to continue the material circulation into the consumer (e.g. rotary atomizer) so that a branch line can be dispensed with entirely. This conceivable solution, however, requires two circulation lines for outgoing and return lines instead of a single stub line and is therefore much more complex. In addition, this requires twice the number of paint hoses up to the color changer, so that the number of possible paint feed lines is reduced due to the limited installation space.

From DE 10 2014004718 A1 a painting system is known in which, when changing color, paint can be pushed out of the branch line by pigs back into the ring line in order to change the color. to minimize sel losses. However, this has nothing to do with the deposition of the paint in the branch line, but is used solely to recover the paint remaining in the branch line.

Furthermore, reference should be made to DE 29 23 906 C2 for the technical background of the invention.

The invention is therefore based on the object of creating a correspondingly improved paint supply system and an associated operating method.

This object is achieved by a paint supply system according to the invention or by a corresponding operating method according to the independent claims.

The paint supply system according to the invention is used to supply a coating system with a coating agent, which is preferably a paint that is used for painting motor vehicle body components. However, with regard to the type of coating agent, the invention is not limited to paints, but can also be implemented with other types of coating agents. In addition, the invention with regard to the type of coating system is not limited to painting systems for painting motor vehicle body parts. Rather, the paint supply system according to the invention can also be used to supply coating systems that coat other types of components.

In accordance with the prior art, the paint supply system according to the invention also has at least one ring line for the circulation of a coating agent (e.g. paint). Such ring line systems are known per se from the prior art and are described, for example, in Pavel Svejda: "Processes and application methods in industrial painting technology", Vincentz-Verlag 2003. It should be mentioned here that in practice several ring lines are usually provided in In the following, however, for the sake of simplicity, mostly only the removal of the coating agent from a single ring line is described. It goes without saying, however, that the coating agent is generally removed from several ring lines.

The removal of the coating agent from the ring main takes place at a ring main extraction point that is connected to a consumer (eg rotary atomizer) via a branch line. At this point it should be mentioned that the invention is not limited to atomizers (for example rotary atomizers) with regard to the consumer. In the context of the invention, the consumer can also be another component or assembly that requires the coating agent.

The invention is now characterized in that the initially described disruptive deposition of the coating agent in the branch line is prevented. For this purpose, the paint supply system according to the invention has a device which moves the coating agent in the stub line alternately forwards and backwards in order to avoid the deposition of the coating agent in the stub line.

This forward and backward movement of the coating agent in the branch line can take place differently in different variants of the invention. In the following, a first variant of the invention is first described, which for this purpose initiates pressure surges via the ring line into the stub line, which are reflected in the stub line, which leads to the forward and backward movement of the coating agent in the stub line.

In this first variant of the invention, the consumer (e.g. rotary atomizer) removes the coating agent from the stub line at a stub line extraction point, the stub line being closed downstream behind the stub line extraction point and at its end containing a cushion of a compressible medium (e.g. air cushion) that contains pressure surges from the pressure line re inflected and thereby the standing in the stub coating agent alternately moves forwards and backwards.

In this first variant of the invention, the pressure surges in the branch line are generated by a pressure generator (e.g. coating agent pump) which pumps the coating agent through the ring line. This pressure generator is then activated by a control unit in such a way that the pressure in the branch line fluctuates jerkily. This can be done, for example, by alternately switching the pressure generator (e.g. coating agent pump) on and off. As a result, pressure surges are initially generated in the ring line, which then spread over the stub line and are reflected at the end of the stub line, which then leads to the forward and backward movement of the coating agent in the stub line.

The desired reflection of the pressure surges at the end of the branch line is preferably carried out by a cushion of a compressible medium (for example air cushion) at the end of the branch line, the cushion preferably has a volume which is 10% -150%, 20% -130% or 30% -110% of the volume of the stub line. For the sake of completeness, however, it should also be mentioned that the cushion can also be dispensed with within the scope of the invention.

It should also be mentioned that the coating agent column in the branch line, together with the elastic cushion at the end of the branch line, forms an oscillatory system that has a specific natural frequency. The vibration excitation by the pressure generator then takes place preferably at the natural frequency or at least close to the natural frequency of this system capable of vibrations in order to move the coating agent column in the branch line as intensively as possible forwards and backwards. If the pressure generator (e.g. coating agent pump) is alternately switched on and off to generate the pressure surges, this switching on or off is preferably carried out at a switching frequency that corresponds to the natural frequency of the oscillatory system that is generated by the coating agent column in the branch line and the Pad is formed at the end of the branch line. For example, the deviation between the excitation frequency of the vibration excitation by the pressure generator (e.g. coating agent pump) on the one hand and the natural frequency of the vibratory system consisting of the coating agent column in the branch line and the cushion at the end of the branch line on the other hand can be less than 20%, 10%, 5% or 2 %.

The desired forward and backward movement of the coating agent in the branch line can, however, also take place differently in a second variant of the invention, so that this second variant of the invention is now described below.

In the second variant of the invention, the branch line opens into a valve arrangement which, on the output side, is connected to the consumer (e.g. rotary atomizer) and to a reservoir. In a first operating mode, the valve arrangement then directs the coating agent supplied via the branch line to the consumer, so that the consumer can apply the coating agent, for example. In a second operating mode, on the other hand, the valve arrangement alternately directs the coating agent from the stub line into the reservoir or from the reservoir back into the stub line. It is thereby achieved that the coating agent in the branch line is alternately moved forwards and backwards.

In one embodiment of this second variant of the invention, the reservoir has a pig line which contains a displaceable pig and leads from the valve arrangement to a pig station. The return of the coating agent from the reservoir back into the branch line can take place here by a pig, which pushes the coating agent back into the stub line, in that the pig is pushed from the pig station in the direction of the valve arrangement. Such pigs and pig stations are known per se from the prior art and therefore do not need to be described in more detail.

The pig line can have a pig station on both sides, so that the movement of the coating agent is driven by pigs in both directions. Alternatively, however, there is also the possibility that the pig line has a pig station only at its distal end. In this case, only the return of the coating agent from the pig line into the branch line is driven by a pig.

In the embodiment with two pig stations at the opposite ends of the pig line, the proximal pig station is connected to the valve arrangement via a connecting line. It is advantageous here if the connecting line has a smaller line cross-section than the pig line.

It should also be mentioned that two or more pig lines can also be connected to the valve arrangement, each of which forms a reservoir and each leads to a pig station.

During operation, the old coating agent in the branch line can then first be transferred to the first pig line. The second pig line is then filled with fresh coating agent from the ring line. In the next step, the old coating agent transferred into the first pig line is pushed back into the branch line and then into the Ringlei device. In the last step, the fresh coating agent transferred into the second pig line is then pressed back into the branch line. As a result, the coating agent in the branch line is not only moved, but is completely or at least partially replaced with fresh coating agent from the ring line.

It should also be mentioned that the valve arrangement can have a color changer (for example linear color changer) which is connected on the input side via a branch line to several ring lines for different coating agents. In this case, coating agents with different colors usually circulate in the various ring lines, the color changer then being able to select the desired color on the input side, which is well known per se from the prior art. For example, such a linear color changer is known from DE 10 2008015 258 A1. The valve arrangement here preferably has a coating agent outlet which is connected to the consumer.

In addition, the valve arrangement can have a pulsed air inlet and a rinsing agent inlet in order to supply pulsed air or rinsing agent, wherein the supply can be controlled by a controllable pulsed air valve or by a controllable rinsing agent valve.

Furthermore, the valve arrangement can have a return connection in order to return media (e.g. coating agents, flushing agents) to a return, the material flow in the return being controlled by a controllable return valve.

In addition, the valve arrangement can have a reservoir connection which is connected to the above-mentioned reservoir (e.g. pig line). The material flow through the reservoir connection into the reservoir and back can be controlled by a controllable reservoir valve.

Furthermore, the valve arrangement can have selector valves in order to optionally pass the flushing agent and the pulsed air on through the reservoir connection into the reservoir, through the return connection into the return or through the coating agent outlet to the consumer.

It has already been briefly mentioned above that the consumer is preferably an atomizer (e.g. rotary atomizer) which can be moved, for example, by a multi-axis painting robot, as is known per se from the prior art. Painting robots of this type are usually designed as articulated arm robots with a proximal robot arm and a distal robot arm. The valve arrangement mentioned above can be attached in or on the proximal robot arm or in the distal robot arm.

In addition, it should be mentioned that the aforementioned reservoir (e.g. pig line) preferably takes up a sufficiently large volume, which is preferably 10% -150%, 20% -130% or 30% -110% of the volume of the branch line.

It should also be mentioned that a metering pump can be arranged between the valve arrangement mentioned above and the consumer (eg rotary atomizer). It should also be mentioned that the invention not only claims protection for the paint supply system according to the invention described above. Rather, the invention also claims protection for a paint shop with such a paint supply system, wherein the paint shop can be used, for example, to paint motor vehicle body components.

Finally, the invention also claims protection for a corresponding operating method. The individual steps of the operating method according to the invention are already apparent from the above description of the paint supply system according to the invention, so that reference is made to the above description with regard to the operating method to avoid repetition.

The invention therefore also includes a control unit which controls the components of the paint supply system according to the invention (e.g. paint pump, return valve of the ring line, color changer valves) in such a way that the operating method according to the invention is carried out. For this purpose, the control unit can have a control computer on which a control program is stored which executes the operating method according to the invention.

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 exemplary embodiments of the invention with reference to the figures. Show it:

Figure 1 is a schematic representation of a paint supply system according to the invention according to a first variant of the invention,

FIG. 2 shows a schematic representation of a paint supply system according to the invention according to a second variant of the invention,

Figure 3A is a schematic representation of a further paint supply system according to the invention according to the second variant of the invention,

FIG. 3B shows a detailed representation of the valve arrangement of the paint supply system according to FIG. 3A, as well as

FIG. 4 shows the operating method according to the invention in the form of a flow chart. The exemplary embodiment according to FIG. 1, which corresponds to a first variant of the invention, will now first be described below.

This paint supply system according to the invention initially has a paint container 1 which is filled with paint 2 in a conventional manner. The paint 2 is removed from the paint container 1 by a paint pump 3 and pumped through a ring line 4, which is well known per se from the prior art.

The paint pump 3 is controlled by a control unit 5, the control line 5 varying the delivery rate of the paint pump 3 and being able to switch the paint pump 3 on and off.

The ring line 5 then opens again into the paint container 1, with a controllable return valve 6 being arranged at the end of the ring line 4, which is controlled by a control unit 7. The two control units 5 and 7 can be designed separately or be part of a common control system.

It should also be mentioned that instead of the controlled return valve 7, a conventional counterpressure valve can be provided that sets a constant coating agent pressure in the ring line 4 upstream of the counterpressure valve, which is also well known from the prior art. An example of such a ring line system with a counterpressure regulator is known from US Pat. No. 7,828,527 B2.

In addition, the drawing shows a rotary atomizer 8, which is only shown schematically here and removes the paint to be applied via a branch line 9 at a ring line extraction point 10 from the ring line 4. The application of paint by the rotary atomizer is controlled by a main valve 11, which is only shown schematically.

In contrast to the prior art, the branch line 9 is led through the rotary atomizer 8, the rotary atomizer 8 taking the paint to be applied from the branch line 9 at a branch line removal point 12.

It should also be mentioned that the branch line 9 is closed at its end and contains an air cushion 13 there, which is used to reflect pressure surges, as will be described below.

If the rotary atomizer 8 does not remove any paint from the branch line 9, then the Lacquer in the stub line 9. There is then the risk that the lacquer will settle in the stub line 9 or change its viscosity in the event of longer idle times, which is also undesirable. The invention therefore provides that the paint in the stub 9 is moved back and forth in such downtimes in order to prevent the annoying deposition of the paint in the stub. For this purpose, the control unit 5 controls the paint pump 3 in such a way that the paint pump 3 is alternately switched on and off. This initially generates pressure surges in the ring line 4, which then propagate via the branch line 9 to the end of the branch line 9, where the pressure surges are then reflected on the elastic air cushion 13. This has the consequence that the standing paint in the branch line 9 is alternately moved forwards and backwards.

It should be mentioned here that the paint supply system with the paint column in the branch line 9 and the elastic air cushion 13 forms a system that can vibrate. To achieve the most intensive back and forth movement of the paint in the stub line, the excitation frequency of the pressure surges should be adapted to the natural frequency of the oscillating system. For this purpose, the control unit 5 controls the paint pump 3 with a corresponding excitation frequency.

A second variant of the invention, which is shown in FIG. 2, is now described below. However, this variant of the invention partially corresponds to the first variant of the invention described above. To avoid repetition, reference is therefore also made to the above description of the first variant of the invention, the same reference numerals being used for corresponding details.

This second variant of the invention is initially characterized by a color changer 14, which has a plurality of color valves F1-Fn on the inlet side, each of which is connected to a ring line. For the sake of simplicity, only the ring line 4 is shown here, which is connected to the color valve F1 of the color changer 14 via the branch line 9. In fact, however, the other color valves F2-Fn of the color changer 14 are each connected via a branch line, not shown, to a respective ring line, not shown.

In addition, the color changer has a coating agent outlet 15 to which the rotary atomizer 8 is connected.

The color changer 14 also has a detergent connection 16 for supplying detergent, the detergent supply via the detergent connection 16 through a detergent valve V in the color changer 14 is controlled.

The color changer 14 also has a pulsed air connection 17 for supplying pulsed air, where the pulsed air supply via the pulsed air connection 17 is controlled by a pulsed air valve PLI in the color changer 14.

The color changer 14 also has a return connection 18 for returning media (detergent, pulsed air, paint) to a return 19, the material flow into the return 19 being controlled by a return valve RF2 in the color changer 14.

This variant of the invention is now characterized in that the color changer 14 additionally has a reservoir valve VRE in order to be able to guide the paint standing in the branch line 9 into a reservoir. The reservoir is formed here by two pig lines 20, 21 which open into a pig station 22, 23 at their distal end. A pig 24, 25 can be displaced in each of the pig lines 20, 21, the movement of the pigs 24, 25 from the pig stations 22, 23 in the direction of the color changer 14 using compressed air, as is known per se from the prior art.

The mode of operation of this second variant of the invention is now briefly described below.

If the rotary atomizer 8 is at a standstill for a longer period of time and therefore no paint is required, there is a risk that the paint in the branch line 9 will settle or at least change its viscosity. In this case, the reservoir valve VRE is then first opened and the old paint in the branch line 9 is transferred into the pig line 20.

In a second step, fresh paint is then transferred from the ring line 4 through the reservoir valve VRE into the other pig line 21.

In the next step, the pig 24 then presses the old paint located in the pig line 20 back into the branch line 9 and finally also into the ring line 4.

In a further step, the pig 25 then presses the fresh paint located in the pig line 21 back into the branch line 9.

10

] As a result, the old paint standing in the branch line 9 is completely or at least partially replaced by fresh paint from the ring line 4.

The exemplary embodiment according to FIGS. 3A and 3B will now be described below, which likewise corresponds to the second variant of the invention and is a modification of the exemplary embodiment according to FIG. To avoid repetition, reference is therefore made additionally to the preceding description, the same reference symbols being used for corresponding details.

First of all, it should be mentioned that the color changer 14 is designed as a linear color changer and is arranged in a distal robot arm 26 of a painting robot. The color changer 14 here has two valve assemblies 14.1, 14.2 which can be displaced relative to one another along the double arrows in order to select one of the color valves F1-Fn of the valve assembly 14.1 for material removal.

The coating agent outlet 15 of the valve assembly 14.2 of the color changer 14 is connected to the rotary atomizer 8 via a metering pump 27, the material output by the rotary atomizer 8 being controlled by a conventional main needle valve HNA in the rotary atomizer 8.

In addition, the rotary atomizer 8 here has a return valve RF1A and a short flush valve KS, as is known per se from the prior art.

The valve assembly 14.2 here also has a reservoir valve LFB, which corresponds to the reservoir valve VRE according to FIG. The reservoir valve LFB makes it possible to guide the paint standing in the branch line 9 into a reservoir, which consists of a connecting line 28 and a pig line 29, the pig line 29 having a larger line cross-section than the connecting line 28. The pig line 29 leads to a pig station, not shown, which makes it possible to push the paint transferred into the reservoir back into the branch line 9, as has already been described above with reference to FIG.

In addition, the valve assembly 14.2 also has selection valves LVPLA, LVPLB, LSV, which allow the flushing agent and the pulsed air to be fed to the reservoir (ie the connecting line 28 and the pig line 29), to the return 19 or to the rotary atomizer 8 conduct.

11

] The flowchart according to FIG. 4 is now described below, which shows the operating method according to the invention according to the first variant of the invention in schematic form.

In a step S1, the paint is circulated in the ring line 4.

In a step S2, the paint is then withdrawn from the ring line 4 into the branch line 9 to the rotary atomizer 8. In the next step S3, the paint is then conveyed through the branch line 9 to the rotary atomizer 8.

In a step S4 it is then continuously checked whether there is a longer standstill in which the rotary atomizer 8 does not require any paint.

If this is the case, the lacquer in the branch line 9 is alternately moved forwards and backwards in a step S5 in order to avoid the lacquer settling in the branch line.

The invention is not limited to the preferred exemplary embodiments described above. Rather, a large number 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 the features of the subclaims independently of the claims referred to in each case and in particular also without the features of the main claim. The invention thus comprises various aspects of the invention that are protected independently of one another.

12th

] List of reference symbols:

1 paint container

2 paint

3 paint pump

4 ring line

5 Control unit for paint pump

6 return valve

7 Control unit for return valve

8 rotary atomizers

9 branch line

10 ring main tapping point

11 Main valve in the rotary atomizer

12 branch line tapping point

13 Air cushion at the end of the branch line

14 color changers

14.1, 14.2 valve assemblies of the color changer

15 Coating agent outlet of the color changer

16 Detergent connection of the color changer

17 Pulse air connection of the color changer

18 Return connection of the color changer

19 repatriation

20, 21 pigging lines 22, 23 pigging stations

24, 25 newts

26 robotic arm

27 Dosing pump

28 connecting cable

29 Pig line

14.1, 14.2 Valve assemblies of the color changer Fl-Fn color valves of the color changer

HNA main needle valve in the rotary atomizer

KS short flush valve in the rotary atomizer

LFB reservoir valve

LVPLA selection valve LVPLB selection valve

LSV selection valve

PL pulse air valve

PLI pulse air valve RF1A return valve in the rotary atomizer RF2 return valve of the color changer V flushing agent valve of the color changer

VRE reservoir valve of the color changer

Claims

Expectations

1. Paint supply system for a coating system, in particular for a painting system for painting motor vehicle body components, with a) a ring line (4) for the circulation of a coating agent (2), in particular a paint, b) a ring line extraction point (10) in the ring line (4) for Removal of the coating agent (2) from the ring line (4), c) a consumer (8), in particular an atomizer (8), which is supplied with the coating agent (2), and d) a branch line (9) which leads from the ring line removal point (10) to the consumer (8), characterized by e) a device (3, 5, 13; 14-25) for the alternating forward and backward movement of the coating agent (2) in the branch line (9) to to avoid settling of the coating agent (2) in the branch line (9).

2. Paint supply system according to claim 1, characterized in that a) that the consumer (8) removes the coating agent (2) at a branch line removal point (12) from the branch line (9), b) that the branch line (9) downstream behind the branch line removal point ( 12) ge is closed, and c) that the stub line (9) at its end holds a cushion (13) of a compressible medium ent, in particular an air cushion (13) that reflects pressure surges from the stub line (9) and thereby that in the Stub line (9) standing coating agent (2) alternately moved forward and backward, d) that the pressure surges in the stub line (9) are preferably generated by a pressure generator (3), in particular by a coating agent pump (3), which the Beschich processing agent (2) pumps through the ring line (4), e) that the pressure generator (3) is preferably controlled by a control unit (3) in such a way that the pressure in the branch line (9) fluctuates jerkily, in particular by alternately switching the pressure generator on and off (3), f) that the cushion (13) in the relaxed state preferably has a volume that is 10% - 150%, 20% -130% or 30% -110% of the volume of the branch line (9),

3. Paint supply system according to claim 1, characterized in that a) that the branch line (9) opens into a valve arrangement (14), b) that a reservoir (20, 21; 28, 29) is connected to the valve arrangement (14), c ) that the valve arrangement (14) is connected on the output side to the consumer (8), d) that the valve arrangement (14) in a first operating mode guides the coating agent (2) from the branch line (9) to the consumer (8), and e ) that the valve arrangement (14) in a second operating mode for alternately moving the coating agent (2) in the stub line (9) alternately forwards and backwards el) the coating agent (2) from the stub line (9) into the reservoir (20, 21; 28, 29) passes and e2) passes the coating agent (2) from the reservoir (20, 21; 28, 29) back into the branch line (9).

4. paint supply system according to claim 3, characterized in that a) that the reservoir (20, 21; 28, 29) has at least one pig line (20, 21; 29) which contains a displaceable pig (24, 25) and of the valve arrangement (14) leads to a pig station (22, 23), and b) that the pig station (22, 23) removes the pig (24, 25) to return the coating agent (2) from the pig line (20, 21) into the branch line (9) moved from the pig station (22, 23) in the direction of the valve arrangement (14).

5. paint supply system according to claim 4, characterized in that a) that the pig line (29) ends on both sides in a pig station, b) that the valve arrangement (14) is connected to the proximal pig station via a connecting line (28), and c) that the connecting line (28) has a smaller cross-section than the Molchlei device (29).

6. paint supply system according to claim 4 or 5, characterized in that the valve arrangement (14) two pig lines (20, 21) are connected, each of which bil the reservoir and lead to a pig station (22, 23).

7. paint supply system according to one of claims 3 to 6, characterized in that a) that the valve arrangement (14) has a color changer (14), which has one in each case

Branch line (9) is connected to several ring lines (4) for different coating agents (2), b) that the color changer (14) is preferably a linear color changer which selects a color by a linear movement of two coupling parts (14.1, 14.2).

8. Paint supply system according to one of claims 3 to 7, characterized in that a) that the valve arrangement (14) has a coating agent outlet (15) which is connected to the consumer (8), and / or b) that the valve arrangement (14) has a pulsed air inlet (17) to supply pulsed air, and / or c) that the valve arrangement (14) at the pulsed air inlet (17) has a controllable pulsed air valve (PL) to control the supply of the pulsed air, and / or d) that the valve arrangement (14) has a detergent inlet (16) to supply a detergent, and / or e) that the valve arrangement (14) at the detergent inlet (16) has a controllable detergent valve (V) to supply the detergent control, and / or f) that the valve arrangement (14) has a return connection (18) in order to return media to a return (19), and / or g) that the valve arrangement (14) has a controllable return valve at the return connection (18) til (LRF2) to the R to open or close the recirculation, and / or h) that the valve arrangement (14) has a reservoir connection to which the reservoir is connected, and / or i) that the valve arrangement (14) has a controllable reservoir valve (LFB) on the reservoir connection to control the coating agent flow (2) from the stub line (9) into the reservoir and from the reservoir into the stub line (9), and / or j) that the valve arrangement (14) selection valves (LVPLA, LVPLB, LSV) has to pass on the flushing medium and the pulsed air optionally jl) through the reservoir connection into the reservoir (20, 21; 28, 29) or j2) through the return connection (18) into the return (19) or j3) through the coating agent outlet (15) to the consumer (8).

9. paint supply system according to one of claims 3 to 8, characterized in that a) that the consumer (8) is an atomizer (8), in particular a rotary atomizer (8), which is moved by a multi-axis painting robot, b) that the painting robot is an articulated arm robot with a proximal robot arm and a distal robot arm (26), and c) that the valve arrangement (14) is attached in or on the proximal robot arm or the distal robot arm (26).

10. paint supply system according to one of claims 3 to 9, characterized in that a) that the reservoir (20, 21; 28, 29) has a volume that is 10% -150%, 20% -130% or 30% -110% of the volume of the branch line (9), and / or b) that a metering pump (27) is arranged between the valve arrangement (14) and the consumer (8).

11. Painting system, in particular for painting motor vehicle body components, with egg nem paint supply system according to one of the preceding claims.

12. Operating method for a paint supply system for a coating plant, in particular for a paint shop for painting motor vehicle body components, in particular for a paint supply system according to one of claims 1 to 10, with the following steps: a) circulation of a coating agent (2) in a ring line (4 ), b) removal of the coating agent (2) from the ring line (4) at a ring line removal point (10), and c) forwarding of the coating agent (2) from the ring line removal point (10) through a branch line (9) to a consumer (8) ), in particular to an atomizer, characterized by the following steps to prevent the coating agent (2) from settling in the stub line (9): d) Alternating forward and backward movement of the coating agent (2) standing in the stub line (9).

13. Operating method according to claim 12, characterized in that a) that the consumer (8) removes the coating agent (2) from the branch line (9) at a branch line removal point (12), b) that the branch line (9) downstream behind the branch line removal point ( 12) is closed, c) that the branch line (9) contains a cushion (13) of a compressible medium at its end, in particular an air cushion (13), and d) that pressure surges are generated in the branch line (9), which are caused by the cushion (13) are reflected at the end of the branch line (9) and thereby move the coating agent (2) in the branch line (9) forwards and backwards.

14. Operating method according to claim 13, characterized in that a) that the coating agent (2) is pumped by a coating agent pump (3) through the Ringlei device (4), and b) that the pressure surges in the branch line (9) are generated by the coating agent pump (3) is alternately switched on and off.

15. Operating method according to claim 12, characterized in that a) that the branch line (9) opens into a valve arrangement (14), b) that a reservoir (20, 21; 28, 29) is connected to the valve arrangement (14), c ) that the valve arrangement (14) is connected on the output side to the consumer (8), d) that the valve arrangement (14) in a first operating mode guides the coating agent (2) from the branch line (9) to the consumer (8), and e ) that the valve arrangement (14) in a second operating mode for alternately moving the coating agent (2) in the stub line (9) alternately forwards and backwards el) the coating agent (2) from the stub line (9) into the reservoir (20, 21; 28, 29) passes and e2) passes the coating agent (2) from the reservoir (20, 21; 28, 29) back into the branch line (9).

16. Operating method according to claim 14, characterized in that a) that the reservoir (20, 21; 28, 29) has a pig line (20, 21; 28, 29) which contains a movable pig (24, 25) and of which Valve arrangement (14) leads to a pig station (22, 23), and b) that the pig station (22, 23) removes the pig (24, 25) for returning the coating agent (2) from the pig line (20, 21; 28 , 29) is moved into the branch line (9) from the pig station (22, 23) in the direction of the valve arrangement (14).