EP1010469A2 - Process and system for supplying paint to an electrostatic coating installation - Google Patents

Abstract

Exchangeable containers are movable by a gripping device (26), insulated against earth to the material removal point (1,2), supplied with high voltage from the spraying unit (10), across an insulated stretch (30). The gap is sufficient for ensuring the high voltage insulation of the material removal point (1,2). The containers are movable linearly across the insulated stretch.

Description

The invention relates to a method and a system for Paint supply according to an electrostatic coating system the preamble of the independent claims, in particular suitable for the series coating of vehicle bodies are.

For the electrostatic series coating of workpieces of the type considered here with water-based paint and other relative It is known that there is a highly conductive coating material Problem of electrical insulation between those on high voltage lying atomizers or other spray devices and a grounded material supply system. For plants at to which the atomizers are supplied from a loop system, in which the available materials of different shades circulate continuously are two for this in principle different possibilities known: Either were grounded Atomizer with insulated external electrodes for charging the Coating material used or any instead Intermediate containers that alternate with the material removal atomizers lying on high voltage and for refilling with be connected to the grounded supply system. If coating company without switching off the high voltage when refilling two separate intermediate containers were to be possible used (DE 29 00 660; EP 0 455 107 and 0 455 109). To establish the respective connections between the intermediate containers and the spray device or the grounded supply system it is known e.g. pneumatically movable Use separating clutches (WO 87/05832; US 4,313,475), the Isolation distance according to the electrical throwover distance the applied high voltage is measured.

From EP 0 792 695 there is also a paint supply system for an electrostatic coating machine is known in which containers that can be filled with the coating material can be rotated on a arranged in the coating machine and from this document from one filling point to one tapping point distant from the filling point and from this are pivotable back to the filling point. The containers are connected to the tapping point via movable color couplings the spraying device and at the filling point with a color changer connected. During material removal during coating are the containers from that to the color changer connected external supply lines while disconnected they are uncoupled from the spray device during filling. During material removal from the with the spray device connected containers are not movements of the rotating base possible, which among other things relatively long material change times surrender.

Recently, for important use cases, too Coating systems preferred where the atomizers are made of the coating machine can be replaced from the outside Containers are supplied.

In a system of this type known from US 4,785,760, the however, only used for painting robots interchangeable container in the spray booth in the movement area of the robot, on paint supply lines connected filling points, from where they are the painting robot depending on your needs. Apart from that the part of the robot where the containers are placed, cannot be under high voltage Loss of time when changing containers. In addition, the robot must Carry out container movements with complex controls.

Less time lost and a comparatively simple control enables a known from EP 0 796 664 and 0 796 665 system also working with interchangeable containers, in which the paint container from one filling point to one Transfer point transported and from there with one of one Pneumatic cylinder unit movable gripper in a material removal point be used. After use, the containers retrieved from the gripper to the transfer point and then transported back to the filling point. The interchangeable Containers are used advantageously for coating a workpiece, for example a vehicle body, or a certain amount of paint required filled.

Starting from the last known system, the Invention, the object of a method and system for Paint supply for an electrostatic coating system exchangeable containers that can be fed with the spray device for water-based paint or similar conductive coating material specify, where the basic Advantages of the known system that applied to the spray device High voltage not switched off when changing containers must be, so that there is the possibility of the coating company not to be interrupted when changing containers.

This task is characterized by that in the claims Processes and systems solved.

According to a first aspect of the invention, there is the advantage that the desired supply principle with a possibly considerable Number of relatively small interchangeable containers (Cartridges) with conductive coating material even with continuous high-voltage spray device enabled and also the material removal point when inserting the container may be on high voltage, even though the entire Supply area for these containers is grounded.

In another aspect, the invention has the advantage that an endless coating from an unlimited number of containers is enabled, which after use continuously without interruption of the coating company against new containers Color types can be changed as long as no color change is required. Even the color change can be done with the least possible Wasted time.

Fig. 1

ein schematisches Prinzipbild des hier beschriebenen Systems;

Fig. 2

eine perspektivische Darstellung einer zweckmäßigen Ausführungsform einer Behälterwechseleinrichtung für das System nach Fig. 1; und

Fig. 3

die Einrichtung nach Fig. 2 in einer anderen Betriebsstellung.

The invention is explained in more detail using an exemplary embodiment shown in the drawing. Show it:

Fig. 1

a schematic block diagram of the system described here;

Fig. 2

a perspective view of an advantageous embodiment of a container changing device for the system of FIG. 1; and

Fig. 3

2 in a different operating position.

The system shown in Fig. 1 is used for paint supply a spray device that is continuously under high voltage 10, e.g. one or usually several electrostatic Rotary atomizers in the usual way with upstream metering pump 11 can exist. The spray device 10 is a distribution valve arrangement 12 upstream, on the two lines 14 and 15 serving as color channels are connected or can be connected via the distribution valves can optionally be connected to the spray device 10. Between each of the lines 14 and 15 and the manifold valve assembly 12 is one in the example shown Separating clutch 16 or 17 switched, the one of a pneumatic Cylinder and piston unit driven coupling element Is movable over an insulating section, which is used to isolate the spray device 10 lying on high voltage against earth is sufficient is measured. The spray device 10, the distributor valve arrangement 12 and the separating clutches 16, 17 can are located in a movable coating machine part 18, for example in the roof beam of a conventional roof machine for the automotive coating.

In this case, the lines consisting of flexible hoses 14 and 15 are arranged with high voltage insulation against earth and lead at their ends facing away from the spray device 10 in a material removal point, which is also insulated from the earth 1 or 2 in a total of 20 Container change area, which is in a constantly grounded Part in or next to the machine or coating system located and can be stationary.

The material change area 20 also includes various grounded ones Supply points 3, 4, 4 'and 4' 'for the material removal points 1, 2 interchangeable containers to be used (which in 1 are not shown). After insertion into the supply point 3, which has a color change valve arrangement FW is connected to ring lines in the usual way emptied containers for reuse in the container change area 20 to be filled by yourself. At the supply points 4 to 4 '', which can serve as buffer spaces on the other hand, externally filled containers are provided and / or after Use can be removed again from the container change area 20. According to a particular advantage of this system, the system can at the buffer or supply points 4, 4 'and / or 4' ' can also be manually loaded with containers, which is especially for Containers with special colors that are rarely needed are useful can be and providing a virtually unlimited Wide range of colors available. Also a rotating one Container magazine (not shown) for a variety of interchangeable Container can be at one of the supply points 4, 4 ' or 4 '' can be provided.

With few (e.g. fewer than 10) additional supply points especially for less frequently used colors, that with almost everyone in practice (e.g. in vehicle painting) occurring color requests a color change without the Is feasible during the color change one Having to rinse the container. The same applies to the case that Before changing colors, consecutively select the same color material two or more containers is removed.

While the supply points 3 to 4 '' are always earthed, can the material removal points 1 and 2 during the continuous Coating operation from the spray device 10 via the lines 14, 15 connected to this continuously be applied to the applied high voltage. You are therefore housed in special high-voltage chambers (Fig. 2 and 3), which the required high voltage insulation of the Material removal points against the grounded parts of the container change area 20 ensure.

The container changing device arranged in the area 20 consists mainly of a rotatable grounded Turntable 22 on which two gripping devices 23 and 23 ' are mounted. Each gripping device has a drive device 24 or 24 ', for example in the form of a pneumatic Piston and cylinder unit for a preferably straight, e.g. rod-like insulating arm 25 or 25 ', at its free end a gripper 26 or 26 'is arranged. The grippers 26 and 26 ' can be made of metal. Arrangement and formation of the isolating arm 25, 25 'are such that the gripper 26, 26' when inserted a container in the material removal points 1, 2 against the grounded parts of the gripping device connected to the gripper 23, 23 'is isolated. The two grippers 26, 26 ' can be moved independently of each other.

In their back and forth movements between those shown in Fig. 1 withdrawn positions near the grounded Parts of the turntable assembly and their end positions on or in the material removal points 1, 2, the grippers 26, 26 ' via a also for high voltage insulation of the Spray device 10 at high voltage material removal points 1, 2 insulating distance measured against earth moves the between the material removal points and the earthed parts the gripping devices 23, 23 'and the turntable 22 are formed is. The insulating section is indicated by arrow 30 and forms one to the axis of rotation in the example shown of the turntable 22 concentric arcuate insulating area parallel in a horizontal plane in the example described to the directions of movement of the grippers.

The two isolated material removal points are located accordingly 1, 2 on a concentric to the rotary table axis Circular arc on which is also used to supply the system supply points 3 filled with containers, 4, 4 'and 4' ', so that they are just like the material removal points 1, 2 accessible from each of the two grippers 26, 26 ' are. The linear directions of movement of the two grippers 26 and 26 'can be in accordance with FIG. 1 at or in the material removal points 1, 2 and consequently also at or in the supply point 3, 4, 4 'or 4' 'to which they cut from the rotary table 22 can be pivoted. This ensures that in each case the one gripper a container on the concerned Place to pick up or pick up while at the same turntable position the other gripper there another container can pick up or use. Aside from the isolated ones The container changing devices and their grippers can Program control so that in DE patent application 198 38 805 described system correspond.

Instead, however, it can be more expedient for design reasons be when the directions of movement of the grippers are not on cut the circular arc mentioned, but by appropriate small angular movements of the turntable 22 to the positions 1, 2, etc. are aligned (Fig. 2 and 3).

The interchangeable containers can be found in EP 0 796 664 and 0 796 665 correspond to the dosing cylinders described here but preferably by pressurizing its interior Pistons can be emptied.

Contrary to the representation in Fig. 1 it is assumed that in operation of the system described here, the material removal points 1 and 2 via the disconnect couplings in the connected position 16, 17 to the spray device located at high voltage 10 are connected, that is, via lines 14 and 15 are continuously placed on high voltage. Further be Assume that the spray device 10 is driven by its metering pump 11 via the distributor valve arrangement 12 coating material from a container inserted into the material removal point 1 fed. So while the coating material is out of this Can be sprayed at the same time, for example, a second container in the supply point 3 by the connected there Color changer can be filled. After filling the second container becomes one of the gripping devices 23 or 23 'removed from the supply point 3 by turning of the turntable 22 in the shown in the drawing for Reaching the second material removal point 2 required Position pivoted and then by extending the concerned Gripper 26 or 26 'over the insulating section 30 in the live material removal point 2 used. There is the container that has been at earth potential until then automatically to the high voltage potential of the spray device raised, a possibly undesirable to sudden Potential changes can be avoided by suitable means can. Now the second container can be opened by opening the corresponding one Valve of the distribution valve assembly 12 to the first container connected in parallel, ie with the same spray device 10 Material removal can be connected. The spray operation can thus continue without interruption. Usually connects the distributor valve arrangement 12 only then the second container with the spraying device if, after emptying the first Container whose connection has broken. While the spray device 10 is now supplied from the second container the first container can be removed from one of the gripping devices 23 or 23 'removed from the material removal point 1 and either be brought to the supply point 3 for filling or instead to one of the buffer supply points 4, 4 ' or 4 '' where it is removed from the system and against an external one filled container can be replaced. So that with High voltage potential coming from the material removal point Container when the gripper is pulled back into the earthed area the system can be unloaded easily and in a defined manner it should be useful to isolate the isolating arm 25, 25 'between the gripper 26, 26 'and earth connected appropriately dimensioned Bridge resistance.

After inserting a container into one of the material removal points 1 and 2 are the grippers in the example considered again from the one remaining in the material removal point Container released and in its retracted starting position moved back.

The separating clutches 16 and 17 are not described here Additional functions especially when changing colors expedient. For similar reasons, lead from the manifold valve assembly 12 on the illustrated additional separating clutches insulated flush and return hoses 33 and from the Material removal points 1 and 2 additional return lines 31 from the movable machine part 18 or from the container changing area 20 out. The separating clutches 16 and 17 could with the continuous spray operation described but possibly also for high voltage insulation of the spray device 12 serve from the grounded material changing device, especially if a container changing device without the Insulated gripper function is provided.

In the embodiment shown in Fig. 2 one for system described suitable container changing device the two material removal points 1 and 2 each in a cylinder housing 41 or 42 made of insulating material. The the two cylinder housings 41, 42 are vertical with their longitudinal axes on a stationary base in or next to the coating machine, that is, perpendicular to that assumed to be horizontal Plane of motion of the isolating arms shown at 43 Gripping devices (23 in Fig. 1). In the cylinder housings 41 and 42 are all fixed parts of the material removal points 1, 2 included, which are placed on high voltage. The distance of these high voltage parts from the metallic ones grounded parts of the turntable 22 and the gripping devices and that is the above-mentioned isolation gap at least as large as that prescribed for a given high voltage and standardized minimum air insulation distance (with a typical example 380 mm).

2 and 3 gripping devices 43 and 43 'are provided, an insulating arm 25 or 25 'in the form of a straight have elongated body made of insulating material, which on his one, the material removal points 1, 2 facing away from the end Piston serving as a drive device 24 (FIG. 1) pneumatic cylinder unit 44 is attached. At his free at the other end, the insulating arm 25, 25 'carries an elongated, with its longitudinal axis vertical, that is, transverse to the plane of movement of the insulating arms extending housing 46 or 46 ' Made of insulating material that is attached to the end face of the insulating arm is scheduled. In this insulating housing 46, for example housed metallic gripper elements with which the Gripping device 43 releasably on holding elements (not shown) on the cylindrical outside of the replaceable, can attack at 48 recognizable paint containers. The total length of the insulating arm 25 and the insulated housing 46 formed insulating body is dimensioned so that for a given High voltage required insulation between the metallic Gripper elements and earth is guaranteed.

2 and 3 is the supply point 3 with their Color change valve arrangement FW shown in more detail in Fig. 2nd without paint container. The color change valve arrangement FW is with connected to a connecting part 50 which contains valve openings, to the openings provided in the bottom of the cylindrical paint containers be coupled for filling. Corresponding connection openings (not shown) are on the floor of the material removal points 1 and 2 within the cylinder housing 41 or 42 for the removal of material from the containers. Since the Paint containers each placed on these connection openings and after filling or removing material should, it is appropriate that located in the insulating housing 46 Gripper elements from a drive unit (not shown) relative to the insulating arm 25 vertically, that is to say transversely to its plane of movement and parallel to the longitudinal axis of the container 48 slidable to store. This lifting movement can, for example be about 20 mm. Instead, the required could Lifting movement but also in a manner known per se Connection elements of the supply point 3 or the tapping points 1, 2 are executed.

The insulating cylinder housings 41, 42 have a cylindrical shape Wall each an opening facing the turntable 22 52 for inserting the container 48. The opening 52 is dimensioned so that the container together with the insulating housing 46 the relevant gripping device 43 can pass through. Usually is the opening 52 through one of the cylindrical outer wall correspondingly curved shield-like cover 54 made of insulating material closed, only for insertion and removal a container to open the opening 52 pushed away will, so that during the rest of the time everyone is on high voltage lying parts of the container changing area 20 (FIG. 1) safely are included. This has the advantage of reducing the Space requirements.

The turntable 22 is preferably made of metal and is like the cylinder units 44 and all others on that of the cylinder housings 41, 42 facing away from the insulating arms 25, 25 ' conductive parts are permanently grounded.

Fig. 2 shows the one gripping device 43 for example Removing a first container from the cylinder housing 41 one material removal point 1, while the second gripping device 43 'another container 48 outside the material removal points for insertion in the same cylinder housing 41 ready. During the first container from the tapping point 1 removed and returned to the grounded turntable 22 , it is also above the discharge resistance mentioned above connected to earth.

In Fig. 3, the changing device is in the subsequent Position shown in which the second container 48 in the now again closed cylinder housing 41 inserted and that of first containers 48 'removed there by the gripping device 43 in the supply point 3 to the color change valve arrangement has been connected.

Another example would also be conceivable that starting 3 straight two containers of the same color in the housing cylinder 41 and 42 inserted and connected to the spray device while a third container (48 ') with the same or another color just filled at the supply point 3 becomes. Then, according to FIG. 2, the third container would then inserted into the housing cylinder 41 during the previously containers (48) removed from there for filling or Change is waiting.

Deviating from the arrangement shown in Fig. 1 are here the two gripping devices 43 and 43 'are not so on the turntable 22 mounted that their directions of movement in the material removal points Cut 1 and 2. To reduce the Rather, they are space-consuming in close proximity with each other parallel (or at a small angle to each other inclined) directions of movement of their insulating arms 25, 25 'mounted. Because of this less bulky arrangement, the turntable must 22 between the removal of a container and the insertion of the new container 48 provided in the same material removal point 1 make a small angular movement to the new container in the position required for insertion bring to.

Claims (24)

Process for supplying paint to an electrostatic coating system for the serial coating of workpieces, in particular vehicle bodies, with a spray device (10) which is at high voltage,
replaceable containers (48) with coating material of selectable color that can be connected to the spray device (10) are provided or filled at a supply point (3, 4) that is at ground potential, while they are decoupled and insulated from the spray device (10),
wherein the containers (48) are moved by a changing device (22, 26) from the supply point (3, 4) to a distant material removal point (1, 2), where they are connected to the spray device (10), and wherein the containers returned to the or another supply point (3, 4) after use,
characterized in that the interchangeable containers (48) from a gripper (26) which is essentially insulated from earth to the material removal point (1, 2) placed at high voltage by the spray device (10) via a for high-voltage insulation of the material removal point (1, 2) Earth sufficient insulation distance (30) to be moved. Method according to claim 1,
characterized in that the containers (48) are moved linearly over the insulating section (30). The method of claim 1 or 2,
characterized in that during the removal of material from a container (48) inserted into a first removal point (1) another container is moved by the gripping device (23) on the way between an earthed supply point (3, 4) and a second material removal point (2) becomes. Method according to the preamble of claim 1,
characterized in that at least two containers (48) containing coating material to be sprayed are provided at each material removal point (1, 2) and are simultaneously connected to the high-voltage spray device (10) via an electrically conductive connection (14, 15). Method according to claim 4,
characterized in that the first container is connected to the high-voltage spray device (10) for removing material,
that after the material has been removed from the first container, the connection between it and the spray device (10) is blocked for the material,
that when the connection between the first container and the spray device (10) is blocked, the second container is connected to the spray device for material removal,
and that during the removal of material from the second container, the first container is transported from the changing device (22, 26) to a refill or other supply point (3, 4) or is exchanged for a third container which has already been filled. Method according to that of the preceding claims,
characterized in that the connection between the material removal points (1, 2) and the spray device (10) is established and interrupted by a separating coupling (16, 17). Method according to one of the preceding claims,
characterized in that the containers are emptied at the material removal points (1, 2) by program-controlled displacement of a piston in the container and are connected to a color change valve arrangement (FW) at the supply point (3, 4) or are replaced after use with another container previously provided . Method according to one of the preceding claims,
characterized in that the direction of movement of the gripper (26) is pivoted back and forth between the material removal and supply points (1-4) by a rotatable base (22) about its axis of rotation. System for supplying paint to an electrostatic coating system for the series coating of workpieces, in particular vehicle bodies,
with a high-voltage spray device (10),
with a supply point (3, 4) which is at ground potential, at which exchangeable containers which can be connected to the spraying device (10) can be provided or filled with coating material of a selectable color, and with a container changing device (22, 26) with which the containers can be removed from the supply point ( 3, 4) can be moved to a distant material removal point (1, 2), where they can be connected to the spray device (10) via a line (14, 15), and with which the containers can be used to the or another supply point ( 3, 4) can be returned,
A gripping device (23, 43) is provided for exchanging the containers, said gripping device being arranged on a base (22) which is at ground potential and having at least one gripper (26) which can be moved relative to the base (22) and detachably engages the respective container ,
characterized in that the gripper (26) is connected to a part (24) of the gripping device (23, 43) which is essentially insulated from high voltage and via an insulating section (30) which is used to insulate the voltage from the spray device (10) to high voltage placed material removal point (1, 2) is dimensioned against earth, to the material removal point (1, 2) and can be moved away from it. System according to the preamble of claim 9,
characterized in that at least two material removal points (1, 2), insulated from earth, are provided, which are connected to the spray device (10) via lines (14, 15) connected in parallel and a valve arrangement (12) and can be placed on high voltage by the latter. System according to claim 9 or 10,
characterized in that the gripper (26) can be moved linearly over the insulating path (30) by a drive device (24) which is mounted on a rotatable or pivotable support (22). System according to one of claims 9 to 11,
characterized in that the gripper (26) is arranged on an insulating arm (25) which is connected to a drive device (24) and isolates the gripper from earth when the container is inserted into the high-voltage material removal point (1, 2). System according to one of claims 9 to 12,
characterized in that an earthed supply point (3) connected to a color change valve arrangement (FW) for filling the exchangeable containers at this point (3) and / or one or more earthed supply or container change points (4) for providing filled containers and / or are provided for removing used containers. System according to one of claims 9 to 13,
characterized in that at least two grippers (26, 26 ') which can be moved independently of one another are provided, the linear directions of movement of which are at the material removal point (s) (1, 2) and / or at the supply or container change point (4, 4', 4 '') cut. System according to one of claims 9 to 14,
characterized in that the gripper (s) (26, 26 ') are mounted on a rotatably mounted turntable (22) with which their linear directions of movement can be pivoted in a program-controlled manner between the material removal and supply or container change points (3, 4). System according to one of claims 9 to 15,
characterized in that the or each material extraction point (1, 2) is connected to the spray device (10.) via a line (14, 15) which is insulated from earth and a separating coupling (16, 17), the separating distance of which is dimensioned to isolate the high voltage from earth ) connected is. System according to one of claims 9 to 16,
characterized in that two material removal points (1, 2) for connection to the spray device (10) are connected or can be connected via a line (14, 15) to a distributor valve arrangement (12) upstream of the spray devices (10), with which the spray device ( 10) with simultaneous connection of both material removal points (1, 2) can be supplied either from a container inserted into the first material removal point (1) or from another container inserted into the second material removal point (2). System according to claim 17,
characterized in that at least one additional line (30) is connected to the distributor valve arrangement (12) or can be connected via a high-voltage isolating coupling through which the remaining coating material and / or rinsing liquid is passed in the case of a color changer. System according to one of claims 9 to 18,
characterized in that an additional line (31) is connected to the material removal point (1, 2), through which the remaining coating material and / or rinsing liquid is passed in the event of a color change. System according to one of claims 12 to 19,
characterized in that the insulating arm (25) is mounted on the piston of a pneumatic cylinder unit (44) and carries at its free end an elongated housing (46) made of insulating material and extending with its longitudinal axis transverse to the linear direction of movement of the insulating arm (25) , in which metallic gripper elements are housed. System according to claim 20,
characterized in that the gripper elements can be displaced by a drive device relative to the insulating arm (25) transversely to its longitudinal axis and parallel to the longitudinal axis of the generally cylindrical interchangeable containers (48). System according to one of claims 9 to 21,
characterized in that the material extraction point (1, 2) is located in a housing cylinder (41, 42) made of insulating material and having its longitudinal axis perpendicular to the plane of movement of the insulating arm (25), said cylinder having an opening (52) for inserting the containers (48) Has. System according to claim 22,
characterized in that the opening (52) of the housing cylinder (41, 42) can be closed by a cover (54). System according to one of claims 9 to 23,
characterized in that the insulating section (30) is formed by the distance of the elements of the material removal points (1, 2) which are connected to high voltage from the nearest edge of the metallic earthed support (22) or of the earthed elements (44) located on the support.

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