EP3171983A1 - Coating system for coating objects - Google Patents

Abstract

The invention concerns a coating system for coating objects, wherein a coating material (82) can be dispensed by means of an application device (12) with a dispensing arrangement (16, 18). A supply system (26) comprises at least one first feed container (20.1) for coating material, which is connected via a first supply line (24.1) and a first material valve (32.1) to the dispensing arrangement (16, 18), and a second feed container (20.2) for coating material, which is connected via a second supply line (24.2) and a second material valve (32.2) to the dispensing arrangement (16, 18). Also provided is a cleaning system (52) having at least one first cleaning line (50.1), to which rinsing agent (84) can be fed via a first rinsing agent feed line (56.1), and a second cleaning line (50.2), to which rinsing agent (84) can be fed via a second rinsing agent feed line (56.2). The first cleaning line (50.1) is connected via a first cleaning valve (48.1) to the first supply line (24.1) and the second cleaning line (50.2) is connected via a second cleaning valve (48.2) to the second supply line (24.2). The first cleaning line (50.1) and the second cleaning line (50.2) are connected to each other via a connection line (78), connection points (80.1, 80.2), relative to the flow direction towards the dispensing arrangement (16, 18), being disposed in front of each cleaning valve (48.1, 48.2).

Description

 Coating system for coating objects

The invention relates to a coating system for coating objects, comprising a) an application device with a dispensing device by means of which a coating material can be dispensed; b) a supply system, comprising at least: ba) a first coating material supply container connected to the delivery device via a first supply line and a first material valve; bb) a second supply container for coating material, which is connected via a second supply line and a second material valve to the delivery device; c) a cleaning system with at least one first cleaning line, which can be supplied with rinsing agent via a first rinsing agent supply line, and a second cleaning line, which can be supplied with rinsing agent via a second rinsing agent supply line; wherein d) the first cleaning line is connected via a first cleaning valve to the first supply line and the second cleaning line via a second cleaning valve to the second supply line. Under lines are present all flow paths for fluid

CONFIRMATION COPY to understand the media. In addition to flexible hose lines or rigid lines, this also includes channels incorporated in the body, flow chambers or even through-openings. In the case of passage openings, their axial extent thus predetermines the length of the line formed thereby. In principle, the length of a line in compact systems can be very small and, for example, only 1 mm in the case of through-openings, depending on the material thickness of the element having the passage opening.

With such coating systems, for example, in the automotive industry, articles such as vehicle bodies or body parts are coated with the aid of electrostatically operating application devices. The coating material, e.g. a paint, is thereby discharged from the dispenser and exposed to an electric field in which the dispensed coating material is ionized and transported due to electrostatic forces to the object, which, for this purpose, e.g. is at ground potential. Such an application device may be, for example, a high-rotation atomizer, in which the delivery device comprises a rotating bell cup, from which smallest droplets of paint are thrown off, so that a paint mist is formed.

When an object with a different color is to be painted as the previously coated article, a color change ^¬ must be performed. In order for a color change to take place as quickly as possible and without loss of time, a coating system of the type mentioned in the introduction comprises at least two feed containers, so that alternating operation can take place. In practice this means that the application device is fed from the one storage container with a first coating material while the other supply container is charged with another coating material so that the system is prepared for a color change.

In electrostatically operating systems, the lines in the direction away from the application device during the coating process must build up an insulation gap and be clean and dry for this purpose. The lines are made accordingly from an electrically insulating material. Basically, it is important in coating systems that no air gets into the coating materials, because then it can happen that the funded material volumes no longer match the volumes required for a coating process.

After completion of a painting process remains in the lines always coating material, which was not applied to the object. With respect to environmentally friendly techniques, the claim has increased to recover as much as possible from this material. Order to push material out of the lines in the respective source, without the applied air to the material has become under at ^¬ alia established the so-called pigging technology, tet in the material by means of a pig, of the works as a sliding body, through the lines is encouraged. However, this technique is quite complex and complex pig changing devices, pig washing stations and the like are required.

It is therefore an object of the invention to provide a coating system of the type mentioned, in which coating material can be effectively recovered and which offers an alternative to pigging technology.

This object is achieved in a coating system of the type mentioned above in that e) the first cleaning line and the second cleaning line are connected to each other via a connecting line, wherein connection points, based on the direction of flow 5 to the dispensing device, are each arranged in front of one of the cleaning valves.

By this measure, it is possible to use instead of a pig detergent as a push medium befindlicheso in the lines befindlicheso coating material, since a certain cleaning line can be vented through the connecting line and the other cleaning line connected thereto. Thus, rinsing agent can be vented and bubble-free up to the associated cleaning valve and the coating material located behind it pressed-5, so that no air cushion or generally no gas cushion between the coating material and the detergent can form, which would interfere with the process. In some cases, instead of air, another gas is used as a thrust medium or for drying the lines, which may remain in the piping system.

 For this example, carbon dioxide, nitrogen or the like are conceivable. In any case, the connecting line provides a bypass line to the valves over. It is advantageous if the first cleaning line is connected via a first outlet valve to an outlet line and the second cleaning line via a second outlet valve to an outlet line. The respective outlet valve can then be opened for the purpose of venting for the respective not charged with detergent cleaning line.

It is particularly favorable if 5 a) the first outlet valve in a first outlet line and the second exhaust valve is disposed in a second exhaust passage; b) the first outlet line is connected to the first cleaning line and the second outlet line is connected to the second cleaning line; the first and the second outlet line open into an outgoing manifold. a single shared outlet manifold can be used for ide cleaning lines. is favorable in terms of flow when the first cleaning line, the first flushing agent supply line and the first outlet line open at a first line intersection; the second cleaning line, the second flushing agent supply line and the second outlet line open at a second line crossing each other.

With regard to the supply of detergent, it is effective if the first detergent supply line and the second detergent supply line are connected via a respective flushing valve with a common detergent source.

So that the lines can be dried after flowing through flushing agent, it is advantageous if the cleaning system comprises at least one compressed air source and the Ers ^¬ th cleaning line and the second cleaning line compressed air can be fed. In this case, a separate feeder is favorable by the Cleaning system of the first cleaning line via a first compressed air supply line Compressed air can be supplied to the second cleaning line via a second compressed air supply line

Compressed air can be supplied.

With existing line crossings, as indicated above, an effective distribution of compressed air in the piping system is achieved when the first compressed air supply line opens into the first line crossing and the second compressed air supply line in the second line crossing.

For a well metered supply of the application device with coating material, it is favorable if the first storage container and / or the second storage container is a piston dispenser.

The coating system is particularly effective when the application device is electrostatic and in particular is an electrostatically operating high rotation atomizer.

Hereinafter, an embodiment of the invention will be explained with reference to the drawings. 1 shows schematically a coating system with an application device, a supply device and a flushing device

FIGS. 2 to 8 show the coating system of FIG. 1 in different phases of a cleaning process.

The figures schematically show a coating system 10 for coating objects, for example vehicle bodies or their attachments. The coating system 10 comprises an application device 12, which is shown only schematically in the present embodiment. In the present exemplary embodiment, the application device 12 is an electrostatically operating high-speed rotary atomizer 14 with a rotating bell cup 16.

The application device 12 comprises a dispensing line 18, via which coating material can be dispensed onto a non-specifically shown item. In the present embodiment, the discharge line 18 leads to the bell cup 16 of the high-rotation atomizer 14. The bell cup 16 and the discharge line 18 thus form a delivery device.

The application device 12 can optionally consist of a first feed container 20.1 in the form of a first piston dispenser 22.1 via a first supply line 24.1 of a supply system 26 or from a second feed container 20.2 in the form of a piston dispenser 22.2 via a second

Supply line 24.2 of the supply system 26 are fed with material. The first piston dispenser 22.1 and the second piston dispenser 22.2 respectively illustrate only one example of a first storage container 20.1 and a second storage container 20.2 for coating material.

In order to connect the dispenser 16, 18 with the storage containers 20.1, 20.2, the dispensing line 18 forks at an input end 28 into a first input arm 30.1 and a second input arm 30.2. The first input arm 30.1 is. Via a material valve 32.1 with the first supply line 24.1 and the second input arm 30.2 is connected via a fluid valve 32.2 with the second supply line 24.2 of the supply system 26. For example, the input arms 30.1 and 30.2 can also be opened by passage openings. be formed in the discharge line 18, as it was initially addressed.

The piston dispenser 22. 1 comprises a cylinder 34. 1 in which a piston 36. 1 can be moved by means of a piston drive not specifically shown. The piston 36.1 defines with the cylinder 34.1 a working space 38.1, which is connected to the first supply line 24.1. In addition, the working space 38.1 is connected to an inlet line 40.1 and an outlet line 42.1. The inlet line 40.1 is connected in a manner known per se to a color changing device 44.1, so that the piston dispenser 22.1 can be filled with different materials. In a corresponding manner, a cylinder 34.2, a piston 36.2, a working space 38.2, an inlet line 40.2, an outlet line 42.2 and a color changing device 44.2 are present in connection with the second piston dispenser 22.2. The lines 40.1, 40.2, 42.1 and 42.2 can be closed or released by valves on the respective piston dispenser 22.1 or 22.2, which are not specifically shown for clarity. The supply line 24.1 is connected at a discharge point 46.1 via a cleaning valve 48.1 to a cleaning line 50.1 of a cleaning system 52. The cleaning line 50.1 leads from the cleaning valve 48.1 to a line crossing 54.1, at which the cleaning line 50.1, a detergent supply line 56.1, a compressed air supply line 58.1 and an outlet line 60.1 open into one another.

In a corresponding manner, the supply line 24.2 at an outlet point 46.2 via a cleaning valve 48.2 with a cleaning line 50.2 of the cleaning system 52, which leads to a line crossing 54.2, in which also a detergent supply line 56.2, a compressed air supply line 58.2 and an outlet 60.2 open.

The cleaning lines 50.1, 50.2 detergent can be supplied. For this purpose, the detergent supply lines 56.1, 56.2 are connected via a respective flushing agent valve 62.1 or 62.2 and a Y-line 64 to a flushing agent source 66. The compressed air supply lines 58.1 and 58.2 are each connected via a compressed air valve 68.1 or 68.2 and a Y-line 70 to a compressed air source 72. The outlet lines 60.1, 60.2 are connected via a respective outlet valve 74.1 or 74.2 to an outlet manifold 76.

All valves 32.1, 32.2, 48.1, 48.2, 62.1, 62.2, 68.1, 68.2 and 74.1, 74.2 are check valves which can optionally close or release the respective line passage.

The cleaning lines 50.1 and 50.2 are connected to each other via a connecting line 78. In the present embodiment, connection points 80.1 and 80.2 are arranged for the connection line 78 in each case before one of the cleaning valves 48.1 and 48.2, respectively with respect to the flow direction to the dispenser 16, 18 with the discharge line 18 and the bell cup 16. Consequently, each cleaning line forks 50.1, 50.2 at a connection point 80.1, 80.2 into the connection line 78 and into a respective end section of the cleaning line 50.1, 50.2 which leads to the respective cleaning valve 48.1 or 48.2.

As explained above, coating material remains in the supply lines 24.1 or 24.2, if an application onsvorgang with a coating material is completed.

By virtue of the fact that the two cleaning lines 50.1 and 50.2 are connected to one another via the connecting line 78, it is possible to reclaim this coating material into the associated storage container 20.1 or 20.2, whereby rinsing agent can serve as the conveying medium without a pig having to be used.

This works as follows:

The starting point is the application configuration according to FIG. 2, in which a coating material 82 from the first piston dispenser 22. 1 is applied. For this purpose, the piston dispenser 22.1 was previously filled with the coating material 82 from the associated color changer 44.1. The coating material 82 is shown simply hatched in the figures obliquely. The access to the first supply line 24.1 is open at the first piston dispenser 22.1 and the accesses to the inlet line 40.1 and to the outlet line 42.1 are closed.

The first material valve 32.1 to the discharge line 18 is opened, the second material valve 32.2 and the first and second cleaning valve 48.1, 48.2 are closed. The piston 36.1 presses the coating material 82 in the direction of the application device 12, from which it is applied to an object.

In the cleaning system 52, the compressed air valves 68.1, 68.2 are opened. The flushing valves 62.1, 62.2 and the outlet valves 74.1, 74.2 are closed.

In this configuration, the Y-line 64 is up to the closed dishwashing valves 62.1, 62.2 filled with detergent 84 from the detergent source 66. The rinsing agent 84 is shown simply hatched in the figures. The lines 70, 58.1, 58.2, 56.1, 56.2, 50.1, 50.2, 60.1, 60.2 and 78 are acted upon by compressed air 86 from the compressed air source 72. The compressed air 86 is illustrated hatched diagonally in the figures.

FIG. 3 shows a configuration after completion of the coating process with the coating material 82. The material valve 32.1 is closed and coating material 82 is still present in the first supply line 24.1. In order to clean the supply line 24.1 and recover the coating material 82 there, it now becomes a cleaning process carried out. In this first the compressed air valves 68.1 and 68.2 are closed, whereas the first flushing valve 62.1 and the second outlet valve 74.2 are opened. As a result, flushing agent 84 flows into the line system and via the cleaning line 50.1 in Rich ^¬ tion to the first cleaning valve 48.1. In this case, the flushing means 84 pushes the compressed air 86 out of the first cleaning line 50.1 via the connecting line 78 into the second cleaning line 50.2 and from there via the now accessible outgoing collecting line 76 from the line system.

When the flushing means 84 reaches the first cleaning valve 48.1 and has displaced all the air there, the first cleaning valve 48.1 is opened and the outlet valve 74.2 is closed; this situation is shown in FIG 4. Thus, detergent 84 to flow into the first supply line 24.1, which is pressed free of bubbles Toggle without intervening air to the Beschich ^¬ tung material 82 in the first supply line 24.1. A portion of the rinse 84 flows initially still in the line 78 against the pressure of the air located there, until there builds a back pressure, which prevents further inflow of detergent 84 into the connecting line 78.

Due to the connection line 78, it is possible to guide the flushing means 84 to the application device 12 and to the supply line 24.1 without air getting there. Air, or as initially mentioned generally a gas, in or before the rinsing agent 84, which or which would otherwise interfere with the process ^¬ sen otherwise, can be channeled out of the system in this way.

The rinsing agent 84 now pushes the coating material 82 out of the first supply line 24.1 back into the first piston dosing device 22.1, wherein the phase boundary between the rinsing agent 84 and the coating material 82 is designated by 88.

As can be seen in Figure 4, the piston 36.1 of the first piston meter 22.1 moves back accordingly, so that the working space 38.1 increases.

FIG. 5 shows that the coating material 82 from the first supply line 24.1 has now largely been pushed back into the first piston dispenser 22.1 in the further course. Since a mixing volume of rinsing agent 84 and coating material 82 is formed at the phase boundary 88 between the rinsing agent 84 and the coating material 82, the process is stopped while maintaining a buffer volume 90 in front of the piston dispenser 22.1, so that no part of this mixing volume is introduced into the piston dispenser 22.1 can get. For example, only 70% of the known volume of the first supply line 24.1 are fed back into the piston dispenser 22.1. At the piston dispenser 22.1 the access to the supply line 24.1 is closed and the access to the outlet line 42.1 remains closed, whereas the access to the inlet line 40.1, which leads to the color changer 44.1, is opened. As illustrated in FIG. 6, the coating material 82 is now pressed by the piston 36.1 via the inlet line 40.1 back to the color changer 44.1 and there into the associated material source.

Then the movement of the piston 36.1 is stopped. At the first piston dispenser 22.1, the access to the inlet line 40.1 is closed again, while the entrances to the first supply line 24.1 and to the outlet line 42.1 are opened. The remainder of the coating material 82 in the first supply line 24.1 is pressed by the flushing agent 84 through the working space 38.1 and into the outlet line 42.1. After renewed opening of the inlet line 40.1, flushing agent 84 is also passed over in order to clean it up to the color changer 44.1. In this case, flushing agent 84 coming from the flushing agent source 66 also continues to flow via the connecting line 78 through the second cleaning line 50.2 in the direction of the outlet manifold 76. This is shown in FIG. 7.

Thereafter, the flushing valve 62.1 is closed and opened both compressed air valves 68.1, 68.2, whereby compressed air 86 is pressed into the piping system. The compressed air 86 first presses all the media in the lines on the way via the supply lines 24.1 and the piston dispenser 22.1 out of the line system and blows them dry. Then the cleaning valve 48.1 is closed, the outlet valve 74.2 is opened and the compressed-air valve 68.2 is closed, so that compressed air 86 via the compressed-air valve 68.1 through the cleaning line 50.1, the connecting line 78 and the cleaning line 50.2 to the outlet valve 74.2 and from there through the outlet manifold 76 flows until all lines are blown dry and can be used for the next application process; this last cleaning configuration is illustrated in FIG.

In a process not shown separately, the discharge line 18 is cleaned by flushing means 84 is passed through the material valve 32.1 in the discharge line 18. This is also dry-blown by means of compressed air 86 when the material valve 32.1 is open.

The application and the cleaning process has been explained only with reference to the first piston meter 22.1. During the cleaning process or possibly also previously, the second piston dispenser 22.1 has already been filled with a coating material which is to be applied to an article after the coating material 82 in terms of time. For this purpose, the coating system 10 is now brought into a configuration which corresponds to that according to FIG. 2, in contrast to which the first material valve 32.1 is closed, but the second material valve 32.2 is opened. The cleaning process after completion of the coating process is then carried out accordingly.

Claims

claims 1. Coating system for coating objects, comprising a) an application device (12) with a dispensing device (16, 18), by means of which a coating material (82) can be dispensed; b) a supply system (26) which at least comprises: ba) a first supply container (20.1) for coating material, which is connected to the delivery device (16, 18) via a first supply line (24.1) and a first material valve (32.1) connected is; bb) a second feed container (20.1) for coating material, which is connected via a second supply line (24.2) and a second material valve (32.1) to the dispensing device (16, 18); c) a cleaning system (52) having at least one first cleaning line (50.1), which is supplied via a first detergent supply line (56.1) rinsing agent (84), and a second cleaning line (50.2), via a second detergent supply line (56.2 ) Rinsing agent (84) can be fed; wherein d) the first cleaning line (50.1) via a first Cleaning valve (48.1) with the first supply line (24.1) and the second cleaning line  (50.1) is connected via a second cleaning valve (48.1) to the second supply line (24.2), characterized in that e) the first cleaning line (50.1) and the second  Cleaning line (50.2) via a connecting line (78) are interconnected, wherein connection points (80.1, 80.2), based on the flow direction of the dispensing device (16, 18), in each case before one of the cleaning valves (48.1, 48.2) are arranged. Coating system according to claim 1, characterized in that the first cleaning line (50.1) via a first outlet valve (74.1) having a discharge line and the second cleaning line (50.2) via a second outlet valve (74.2) are connected to an outlet line. Coating system according to claim 2, characterized in that a) the first outlet valve (74.1) in a first outlet line (60.1) and the second outlet valve (74.2) is arranged in a second outlet line (60.2); b) the first outlet (60.1) with the first cleaning ^¬ supply line (50.1) and the second outlet (60.2) with the second cleaning pipe (50.2) connected; c) the first and the second outlet line (60.1, 60.2) open into an outlet manifold (76). Coating system according to claim 3, characterized in that a) the first cleaning line (50.1), the first flushing agent supply line (58.1) and the first outlet line (60.1) merge into one another at a first line crossing (54.1); b) the second cleaning line (50.2), the second detergent supply line (58.2) and the second outlet line (60.2) at a second line crossing (54.2) merge into each other. Coating system according to one of claims 1 to 4, characterized in that the first flushing agent supply line (56.1) and the second flushing agent supply line (56.2) are each connected via a flushing valve (62.1, 62.2) to a common flushing agent source (66). Coating system according to one of claims 1 to 5, characterized in that the cleaning system (52) comprises at least one compressed air source (72) and the first cleaning line (50.1) and the second cleaning line (50.2) compressed air can be supplied. Coating system according to claim 6, characterized in that in the cleaning system (52) of the first cleaning line (50.1) via a first compressed air supply line (58.1) compressed air (86) can be fed to the two ^¬ th cleaning line (50.2) via a second compressed air supply line (58.2) Compressed air (86) can be supplied. 8. Coating system according to claim 7 with reference back to claim 4, characterized in that the first  Compressed air supply line (58.1) in the first line crossing (54.1) and the second compressed air supply line (58.2) opens into the second line crossing (54.2). 9. Coating system according to one of claims 1 to 8, characterized in that the first storage container (20.1) and / or the second storage container (20.2) is a piston dispenser (22.1; 22.2). Coating system according to one of claims 1 to 9, characterized in that the application device (12) works electrostatically and in particular an electrostatically operating high-rotation atomizer (14).