EP2853312B1 - ICC metering - Google Patents

Description

The invention relates to a metering device that can be used for a coating device for the serial coating of workpieces with different colors.

For example, this involves the serial painting of vehicle bodies and their parts using electrostatic or other atomizers, including rotary atomizers, air atomizers, etc., which apply the coating material using an automatically controlled metering device. The term metering device used here preferably means volumetric metering devices, such as gear pumps or piston metering devices, which can be driven by a controllable motor in such a way that the amount of material applied by the atomizer (instantaneous flow) depends on requirements, for example depending on the respective workpiece area and other parameters can be changed, such as in EP 1 314 483 A2 or DE 691 03 218 T2 is explained. The volumetric dosing is typically carried out by controlling the speed of a gear pump or the piston speed of a piston dosing device.

Gear metering pumps are preferred in many cases due to their small size, continuous paint delivery and cost advantages.

Piston dosing devices, on the other hand, have the advantage of higher dosing accuracy by avoiding the slippage between the gear pair and the housing of gear dosing pumps, and in Electrostatic painting equipment, in which high-voltage insulation between the atomizers and their grounded supply system is required, can be easily achieved with the discontinuous paint conveying operation of a piston metering device. Other advantages will be explained.

As in EP 1 772 194 A2 described, it may also be useful to connect the piston metering device of an electrostatic painting device with a container that serves as a buffer for the coating device, which is already filled with the new paint to reduce the required color change times when changing the color, while still painting with the previous color from the piston metering device. This storage container can also be defined as part of a metering device in the sense of the invention. To empty the storage container, it can also contain a piston in the cylinder.

Instead of the volumetric dosage, for example, according to EP 1 287 900 A2 also a color pressure regulator or according EP 1 346 775 A1 the main needle valve of the atomizer serve as an actuator of a control circuit for controlling the amount of paint or outflow rate and thus as a metering device.

It is known to install dosing devices in the atomizer, for example from EP 1 502 658 A1 . DE 101 15 463 A1 . DE 101 36 720 A1 or DE 695 10 130 T2 ,

If an atomizer is to apply coating material with a large number of shades, but for example limited by a ring line system, and a color change is to take place in the shortest possible time, color change valve arrangements usually referred to as color changers are shown in Block construction (ie as a mechanical unit) is used which connects the numerous paint inlets via a central channel to the paint outlet leading to the atomizing element. Due to their usual modular structure, they can be easily adapted to different colors. Typical modular color changers for wet paint are, for example DE 198 36 604 A1 and DE 198 46 073 A1 known, while a basically similar color changer for powder coating in the DE 601 03 281 T2 is described. For example, the flushing of color changers DE 199 51 956 A1 , Color changers of this type are typically connected upstream of the known gear or piston metering devices or, if appropriate, the paint storage container mentioned.

If only a few colors are required, there is also the option of installing a color changer in the atomizer, if necessary with a dosing device downstream of it ( EP 1 502 658 A1 ) to shorten the path to be rinsed during a color change from the color changer to the application organ, such as the bell cup of a rotary atomizer. For this, efforts have been made to construct special space-saving color changers ( EP 1 502 659 B1 ), which is particularly important when double color changers are required, which are known to have common ink supply lines and are connected to the application device via separate ink paths. The installation of a color change valve arrangement in the atomizer, also known in practice as ICC technology (Integrated Color Changer), has the advantage of substantially reducing the loss of color and detergent when changing colors. In the case of car body painting, the loss of color change can be reduced, for example, from about 45 ml of paint per atomizer and color change with conventional color change technology to only about 4 ml. There is a similar reduction in detergent losses. Moreover In typical cases, the color change time can be halved, for example from 12 to 6 seconds, with the result of an increase in the capacity of the coating system of approximately 5-10% or, for example, 30-60 vehicles per day.

A disadvantage of known systems with a color changer built into the atomizer is the small number of selectable color tones, which is restricted by the space requirement of the color changer and the color lines leading into the atomizer. Instead of using one of the usual color changers, i.e. a modular color changing block with an output channel common to the colors, you can also feed the colors, e.g. of ring lines, to the application element via a color hose leading into the atomizer directly via color valves in the atomizer, whereby for each of these colors a separate dosing device can be provided, which consequently does not have to be rinsed when changing colors, and there is the possibility of connecting a larger number of colors that are rarely required (so-called low-runner) via an external color changer, as in the German patent application 10 2006 022 570.8 from May 15, 2006 and in the patent application PCT / EP2007 / 003874 from May 2, 2007, the entire content of which is hereby incorporated into the present description. However, the number of frequently required colors (high-runner) that can be selected is also limited here by the available space in the atomizer, the implementation of the paint hoses by the hand axis of the painting robot and, if dosing devices are connected in advance, by the space required for mounting them on the robot.

The advantage of an unlimited number of applicable color tones is offered by special color supply systems, in which the colors do not come from ring lines, but are generated in a color mixing room and via a color changer to the atomizer be directed. However, these systems are relatively complex and have higher color change losses compared to ring line systems.

As already mentioned, color changers are common in painting systems because, as is well known, they enable a quick change from one color to another during the painting operation. However, they have the basic disadvantage of unavoidable color losses when flushing the more or less large central channel with every color change. After optimizing the color losses in, for example, pigged hoses, dosing devices, etc., the color changer is often the element of the coating system with the greatest single loss to be able to conduct, as may be desired for various reasons (special ink supplies, container technology, higher painting quantities, shorter cycle times of successive workpieces, higher viscosities, etc.). In addition, the loss of color change increases with the number of connected colors and the resulting length of the central channel, so that the number of colors must often be undesirably limited.

In order to avoid the loss of color change in the usual color changers, color changing systems based on the docking principle were developed, in which the color lines provided for the different colors can be coupled to a line leading to the atomizer with mechanically movable valve elements ( EP 1 245 295 A2 . DE 100 64 065 A1 or DE 601 11 607 T2 ). With these color interfaces, compared to the usual color changers, a color saving (typically around 10 ml with each color change) can be achieved, but they have various practical disadvantages such as time-consuming Motion control for moving to the coupling positions, high maintenance requirements, rinsing the interface, drying paint at the interface, leaks etc.

A relatively good solution to the problem of reducing color losses when changing colors is provided by the EP 1 502 657 A2 achieved color changer, the central channel of which is subdivided into sections that can be flushed independently of one another, with the often required high-runner colors, that is to say the colors with a high consumption volume, being connected to the front section located at the color exit, and less frequently to the rear section facing away from the color exit required colors (low-runner) can be connected. While the often required front section is always rinsed independently of the rear section, the less frequently required section can be rinsed together with the other section. Since the entire central channel is no longer rinsed when changing colors, as with conventional color changers, there is less loss of paint and rinsing liquid. However, these remaining color change losses are also undesirable, especially for frequently used colors.

After the output of color changers, a color pressure regulator is usually arranged, which can provide a pre-pressure control of a metering pump or, as already mentioned above, can serve as an actuator for color quantity control. The dead space of this color pressure regulator must be flushed with every color change.

The one already mentioned above EP 1 502 658 A1 discloses an atomizer in which there is a metering pump and a color change valve arrangement connected upstream of this pump in the usual manner In the form of a color changer with valve units connected to a common collecting duct.

EP 1 666 159 A2 discloses the common arrangement of a piston metering device and a color changer in the wrist of a robot.

EP 1 502 659 B1 describes the advantages of particularly small color changers with needle valves.

GB 2 326 833 A. discloses an atomizer on which a housing is arranged, in which there is a metering pump with several inputs for lines which contain controllable color valves for different selectable colors.

Based on the described prior art, such as EP 1 502 658 A1 It is an object of the invention to provide a metering device which can be used for a coating device for coating workpieces, in particular with shades of color that are required differently, with a color change being possible with minimal or little loss of color, detergent and time.

This object is solved by the features of the claims.

In the automotive industry, for example, up to 70 or 80% of the production volume is currently limited to about 7 colors or less. Through the direct connection of these frequently required colors to the automatically controlled dosing device, however, according to the invention, the loss of color change in paint and detergent with the corresponding frequent change of these high-runner colors and, at the same time, the necessary color change times via the advantages described above ICC technology is reduced to a minimum without having to limit the total number of selectable colors, including numerous rarely used or low-runner colors, where color change losses are less serious due to the less frequent color changes. If no typical color changer with a common central channel to be flushed with each color change is used for the high-runner colors, i.e. for the colors most frequently required or, in the same way, for the colors with the largest production volume, the typical color change losses in material and Time. In addition, the loss of color change of a separate typical color changer for less frequently used colors is reduced because its length is shortened accordingly by eliminating the most frequently required colors, unless a correspondingly larger number of selectable colors is to be connected instead.

The color change losses of the high-runner colors are lowest when both the metering device and the color lines required for these colors are accommodated in the atomizer.

With direct connection of all paint lines to one input of the metering device, only the short path common to the colors from the metering device to the application member, such as e.g. B. the bell plate of a rotary atomizer. In this case, the associated color valves, which are controlled by external signals for the choice of color, are preferably attached directly to the metering device or installed therein.

In the context of the invention, it is also possible to arrange only the metering device in the atomizer itself, on the other hand to install the color valves for the high-runner colors only in the vicinity of the atomizer, preferably between the atomizer and the wrist of the painting robot or other moving the atomizer program-controlled automatic machines. In this case, only one output line of the color valves common to the colors runs from these into the metering device in the atomizer, the color valves also being able to form a typical color changer in this case. Furthermore, within the scope of the invention there is the possibility of attaching not only the paint valves but also the metering device outside of the atomizer, preferably between the wrist and the atomizer, since the color change losses are still relatively small in this case as well.

In other cases, on the other hand, it may be more expedient to arrange the metering device and / or the color valves, possibly in a conventional color changer, also in the vicinity of the atomizer, but somewhat further away from it, for example in or on an arm of a person moving the atomizer Coating robots or other program-controlled automatic machines. In particular, it can be expedient, according to the mentioned EP 1 772 194 A2 to accommodate the dosing device consisting of a piston dosing device with an upstream paint storage container in the forearm of a painting robot.

In contrast, the color changer provided for possibly many, but less frequently required, color tones is always arranged separately and further away from the atomizer, preferably in or on an arm of the coating robot or the like. The closer the atomizer is to the color changer, the less the losses when changing the colors, but due to its space requirements and for dynamic and other practical reasons, it is usually not possible to place it in or on the atomizer in front of the wrist for a larger number of colors of the painting robot or the like. As is possible in many cases for the high-runner color valves, but at most in or on the wrist-carrying front robot arm, if not too many colors are connected. In the context of the invention, however, this color changer could also be further away from the atomizer, that is to say in the second robot arm or traveling along (on the so-called axis 7) or even outside the painting robot. In this case, for example, but also for the high-runner color supply described here, color losses during a color change can be achieved by additional measures known per se to the person skilled in the art, such as, in particular, the pigging technique in connection with pushing back the colors remaining in the line into the supply system Avoid ("reflow") and / or almost complete consumption of the paint in the line when applying ("Pushout").

The output of the separate color changer for less frequently used colors is preferably connected in parallel to the color lines of the most frequently required high-runner colors to a separate additional input of the metering device or, if appropriate, its storage container. Instead, the output of this color changer can also be connected directly to the atomizer via a line running parallel to the metering device of the high-runner colors and its own metering device, which can be located in the atomizer or at any distance outside the atomizer. d. H. usually on its main needle valve.

Preferably, in parallel with the separate color changer for less frequently required color tones, a corresponding further color changer is provided, which is connected to color lines for the same color tones. This avoids unwanted loss of time when changing colors, because during the rinsing of one color changer and its output line and while preparing for the next color (possibly including reflow), the atomizer can be supplied from the other color changer. This alternate color supply is usually referred to as A / B operation (see e.g. EP 1314483 A ). The two matching supply branches (A and B) are connected in parallel to one another to the atomizer, in preferred exemplary embodiments of the invention described here to two inputs of the metering device (possibly its storage container) or otherwise via a separate metering device to the main needle valve of the atomizer. A / B operation is also for the invention High-runner color supply possible, for which a corresponding further arrangement of a dosing device and controlled color valves is then provided in parallel to the arrangement of the metering device and the controlled color valves of the frequently required color shades, the color valves of the two arrangements of color lines for the same also being provided here Color tones are connected. Instead, a single piston dosing device, which is designed for alternating operation, can in principle also be used EP 1666158 A2 are used, i.e. a piston-driven metering device with a cylinder, the areas separated by the piston each having several controlled inputs for the selectable different colors and each having a controlled output connected to the main needle or other output valve of the atomizer.

The or (with A / B operation) each color changer for less than the z. B. 7 or less high-runner colors required colors can expediently contain at least two line sections, into each of which several controlled color valves for coating materials with selectable different color tones open, and of which at least one line section can be flushed independently of at least one other line section, the Line sections are connected to one another and / or to an output line of the color changer by a controlled shut-off valve. Such color changers are inherently from the EP 1502657 A2 are known and enable a meaningful further differentiation between colors that are required differently to reduce the color change losses, with colors that are used less frequently being connected to the line section of the color changer further away from the color output and the other colors to its other line section located at the color output.

If two separate, parallel dosing devices are provided in the atomizer or in the vicinity thereof, these dosing devices can also work simultaneously in order to supply the application member with two components of a coating material coming from separate supply lines, such as two-component paints in particular.

According to a particularly preferred aspect of the invention, which in some cases can be expedient and advantageous for less frequently used colors even without the above-described feature of a color changer arranged remotely from the atomizer, the metering device is preferably installed or installed in the atomizer or in its vicinity a piston metering device with a metering drive which can be controlled automatically to change the piston speed during the application, for which one of the constructions known per se from the prior art can be used for this. However, in contrast to the known constructions, the piston metering device according to the invention or possibly its upstream storage container does not have only one or at most (as in the case of the mentioned EP 1666158 ) two inputs, but for each of the selectable frequently required colors at least one separate input and at least one common output for the feedable color materials. In addition to the low loss of material and time when changing colors, a piston metering device has special advantages, for example, compared to gear metering pumps and other metering systems, such as better flushability with less flushing effort and the option of pressing the colors back (reflow) into the supply system, e.g. B. ring lines directly via the color valves, without a color changer and the connecting path between the metering device and the color changer having to be filled. Another significant advantage of the piston metering device is that it does not require a color pressure regulator, as opposed to currently available gear metering pumps, which, for reasons of dosing accuracy, would normally have to be preceded by a separate color pressure regulator for each connected color line. The piston dispenser avoids the disadvantages of pressure regulators such as costs, loss of color when changing colors, space requirements and the weight of the robot axes.

Among others To reduce the loss of color changes and for reasons of space and construction, it is particularly expedient if the color valves of the high-runner color lines, which are controlled by signals for color selection, are attached to the metering device or are structurally integrated into the latter. In the case of a piston metering device or a piston cylinder upstream of it (which is to be understood as a container with any cross-section, including a non-circular one), at least the piston cylinder space on one side of the piston can have a plurality of inputs for the color lines of differently colored coating materials, whereby the inputs preferably have valves built into the cylinder or attached to the cylinder, which can be controlled by signals for selecting the coating materials that can be fed to the piston metering device. Such a piston metering device, with or without an upstream storage container, can also be expedient and advantageous in itself and independently of the coating device described here, that is to say also in any other paint supply system, including systems in which the piston metering device is not located in or near the atomizer. The same applies to the above-mentioned double-acting piston metering device according to the EP 1666158 A2 , in which the inputs of the one area of the cylinder provided for the different selectable colors are located on or in the one end of the cylinder and the inputs of the other area are located on or can be located in the opposite end of the cylinder.

According to another aspect of the invention, which can also be useful and advantageous by itself and also without the feature relating to the arrangement of color changers in or more or less far away from the atomizer, the color change valves can be built into a gear metering pump of the type which is conventional per se or be attached to the dosing pump.

According to a further aspect, which can also be expedient and advantageous on its own and also without other of the described features, instead of the examples described above, the paint valves can also be placed in or on a container of a coating device, e.g. a coating robot to be installed or attached, which is not used for dosing, but in a manner known per se for other purposes such as, for example, as an intermediate or storage container.

The number of color valves installed or attached to or in a metering device or a container of a coating device for a correspondingly large number of color inputs depends on the respective individual case, but is generally more than two and preferably more than four.

Fig. 1

ein vereinfachtes Prinzipschema einer erfindungsgemäßen Beschichtungseinrichtung;

Fig. 2

einen erfindungsgemäßen Kolbendosierer;

Fig. 3

drei verschiedene Farbwechsler, die bei einer erfindungsgemäßen Beschichtungseinrichtung verwendet werden können;

Fig. 4

ein gegenüber Fig. 2 abgewandeltes Ausführungsbeispiel;

Fig. 5

ein Ausführungsbeispiel mit einer Zahnraddosierpumpe;

Fig. 6

eine zweckmäßige bauliche Realisierung der Dosiervorrichtung gemäß Fig. 2;

Fig. 7

einen Radialschnitt durch die Endwand der Vorrichtung gemäß Fig. 6;

Fig. 8

eine zweckmäßige bauliche Realisierung der Dosiervorrichtung gemäß Fig. 4;

Fig. 9

die Anordnung einer Dosiervorrichtung beispielsweise mit einem Behälter gemäß Fig. 6 im Vorderarm eines Lackierroboters;

Fig. 10

eine zweckmäßige bauliche Realisierung der Dosiervorrichtung und ihrer Ventile gemäß Fig. 5;

Fig. 11

den Einbau von Farbventilen in den Umfang eines beliebigen Zwecken dienenden Behälters einer Beschichtungseinrichtung;

Fig. 12

eine Abwandlung des Ausführungsbeispiels nach Fig. 11;

Fig. 13

eine schematische Schnittansicht des Ausführungsbeispiels nach Fig. 12; und

Fig. 14

eine weitere Abwandlung der Ausführungsbeispiele nach Fig. 11 und 12.

Embodiments of the invention are explained with reference to the drawing. Each shows schematically and in a simplified representation:

Fig. 1

a simplified schematic diagram of a coating device according to the invention;

Fig. 2

a piston metering device according to the invention;

Fig. 3

three different color changers that can be used in a coating device according to the invention;

Fig. 4

one opposite Fig. 2 modified embodiment;

Fig. 5

an embodiment with a gear metering pump;

Fig. 6

an appropriate structural implementation of the metering device according to Fig. 2 ;

Fig. 7

a radial section through the end wall of the device according to Fig. 6 ;

Fig. 8

an appropriate structural implementation of the metering device according to Fig. 4 ;

Fig. 9

the arrangement of a dosing device, for example with a container Fig. 6 in the forearm of a painting robot;

Fig. 10

an appropriate structural implementation of the metering device and its valves according Fig. 5 ;

Fig. 11

the installation of paint valves in the scope of any purpose container of a coating device;

Fig. 12

a modification of the embodiment Fig. 11 ;

Fig. 13

is a schematic sectional view of the embodiment Fig. 12 ; and

Fig. 14

a further modification of the embodiments Fig. 11 and 12 ,

In the Fig. 1 The coating device shown contains a metering device 10, to the outlet 11 of which the usual main needle valve or the like of an atomizer (not shown) for colored material, such as an electrostatic rotary atomizer or air atomizer, is connected. The output 11 is common to several, in the example shown, six color inputs of the metering device 11, each of which has a color valve FV1, FV2, etc. to FV6 that is automatically controlled by the higher-level control program for color selection. The metering device 10 can be of any type per se, that is to say it corresponds to one of the metering systems known per se for coating systems, including piston metering devices and gear metering pumps or systems working with color pressure and color quantity control, etc. Volumetric metering devices and in particular piston metering devices are preferred in the invention.

In the example shown, the color lines 13 for the most frequently required or high-runner colors (designated 2 to 6), which are fed, for example, as spur lines from the ring lines customary in coating systems, are connected to the color valves FV2 to FV6 of the metering device 10 are or can even be designed as a ring line. One of the color valves, here FV1, on the other hand, is connected via a color line 15 to the output of an external color changer 12 and is used to separate the high-runner color change area from the low-runner color changer 12. The color changer 12 can have at the outset conventional modular block construction with a central channel, to which the color lines 14 for less frequently used or low-runner colors are connected via the color valves of the color changer. Preferred embodiments of the color changer 12 are shown below with reference to Fig. 3 described.

As has already been explained, the metering device 10 and / or the color valves FV1 to FV6 can preferably be located in the atomizer or can be moved with it in the vicinity thereof, in particular between the atomizer and the wrist of a painting robot or in its forearm. As has also already been mentioned, the color valves are preferably attached to or incorporated into the metering device 10 (piston metering device, storage container, metering pump or, if appropriate, the measuring cell or the color pressure regulator, metering systems known per se, etc.). The external color changer 12, on the other hand, can be located at a location that should be as close as possible to the atomizer in terms of color change losses, but is otherwise largely arbitrary. For dynamic and space reasons, for example, a location on or in the rear robot arm can be useful if an arrangement further ahead cannot be realized.

If the metering device is formed by a piston metering device or a volumetric metering pump, for example with an electric drive motor, the metering drive can be located outside the metering pump (for example as shown in FIG EP 1000667 B ). In particular, the metering drive can also be installed in the piston metering device or in the metering pump.

The paint supply according to the invention is suitable for any atomizer, in particular also for electrostatic atomizers, which are known to charge the coating material to a high voltage potential, for example in the order of 100 kV. In this case, sensors and actuators located in the atomizer, including the metering device and its electrical metering drive, can be at the high voltage potential of the atomizer during operation, as well as, if applicable, an electric drive motor of the bell cup provided instead of the usual compressed air turbine, if it is a rotary atomizer , As detailed in the patent applications DE 10 2006 045 631.9 and PCT / EP2007 / 008382 is described, the metering drive, which is at high voltage potential, and possibly the electric bell-turn motor, which is also at this potential, can be supplied with electrical power by an isolating transformer at least with its secondary coil arrangement in the atomizer. The isolating transformer forms a high-voltage insulation path between its primary and secondary circuits and thus galvanically separates the consumers it supplies, which are located in the atomizer, including the two motors, from the electrical power supply line leading in the atomizer.

As also in the patent applications mentioned DE 10 2006 045 631.9 and PCT / EP2007 / 008382 is described, the control and sensor signals of the actuators and sensors of the atomizer can also be transmitted potential-free into or out of the atomizer, for example optically or via radio. In particular, the external signals controlling the metering drive can be transmitted together with other signals over a common cable or radio link, etc.

According to a special feature that is also advantageous and independent of the high-runner color supply described here is realizable, the actuation of the usual main needle valve or another outlet or main valve of the atomizer can be controlled by the pressure generated at the outlet (11) of the metering device upstream of the main valve. The main valve is therefore opened by the pressure of the metering device as soon as and as long as there is a corresponding pressure, and automatically closed when there is no pressure. The principle of operation corresponds to that of a color pressure regulator that is common in coating systems, such as that made of DÜRR / BEHR technical manual, introduction to the technology of car painting, 04/1999 - 28.04.1999, chap. 5.3.1 Color pressure regulator , or off EP 1 376 289 B1 is known, the complete content of which is hereby incorporated into the disclosure of the present application. Such a color pressure regulator (which does not have to be a "regulator" in the sense of a closed control loop) can in principle replace the piston drive of conventional main needle valves and its external control, the valve not being opened by control air, but by the color pressure itself. Accordingly, the main valve of the atomizer or another application device can preferably consist of a needle valve or also of a ball or other valve for the coating material, which is held in the closed position by spring force and opened by the pressure of the coating material acting against the spring force, for example via a membrane is as soon as this pressure reaches a certain value that can be set fixed or changeable. In the example considered here, the control input of the main valve is connected to the output of the dosing device described. This (indirect) automation of the main needle control by the dosing device eliminates the very complex setting of the main needle circuit of conventional atomizers, the main needle valve of which is known to only be provided by external signals the program control of the coating system is opened and closed (see e.g. EP 1245291 B1 ).

In Fig. 2 A piston metering device 20 is shown schematically, which essentially consists of a cylinder 21, a piston 23 displaceable in the cylinder by the piston rod 22 and a metering drive (not shown). The components of the piston metering device 20 can consist of an insulating material for high-voltage reasons and a ceramic material to improve the metering accuracy. The metering drive can usually contain an electric motor moving the piston rod, which is controlled in a manner known per se so that the instantaneous amount of the applied coating material can be changed as required by changing the piston speed during the coating process. Piston dispensers working according to this principle are off, for example EP 1384885 B and WO 93/23173 known.

According to the invention, however, the piston metering device 20 has several, in the example shown, five color inputs E1 to E5, each of which has a color valve FV1 'to FV5' and is therefore connected to one of five color lines 13 'for different high-runner colors. An additional input E6, which is also provided with a valve VV, is provided for introducing a thinner V serving as a rinsing agent and for pulse air PL also serving for cleaning the cylinder 21. Furthermore, the cylinder 21 has an outlet A with an outlet valve VA, to which an outlet line of the piston metering device leading to the main needle or outlet valve of the atomizer is connected.

The color valves FV are preferably attached to or installed in the cylinder base 24 of the piston metering device, as indicated by the dashed line 24 '. Accordingly The flushing valve VV and / or the outlet valve FA can also be attached or installed.

If the piston metering device 20 is the Fig. 2 as a metering device 10 based on Fig. 1 described device is used, one of the color inputs such as E1 to E5 of the piston metering device (instead of a high-runner color line) can also be connected to an external color changer, that is to say, for example, from the color changer 12 in Fig. 1 coming color line for rarely needed colors. Instead, however, the output line of an external color changer could also bypass the piston metering device 20 to the output valve of the atomizer.

Within the scope of the invention, element 20 in Fig. 2 also according to, for example, a paint storage container connected upstream of the actual piston metering device EP 1 772 194 A2 act, the piston of which is usually not driven by an electric motor, but in the filling direction by the coating material and in the emptying direction by a pressure medium such as compressed air.

According to a further development of the piston metering device 20 for alternate operation of the cylinder regions separated by the piston 23 EP 1666158 A2 For example, an arrangement corresponding to the inputs E1 to E6 and the output A with the associated valves could be provided in the cylinder base of the piston metering device opposite the cylinder base 24.

The external color changer 12 (provided in the preferred embodiments of the invention) Fig. 1 ) for less frequently used colors, the in Fig. 3 in (a) schematically shown known design, such as from DE 19836604 A1 . DE 19846073 A1 or DE 19951956 A1 is known per se. It therefore essentially consists of color valves for twenty-four different colors in the example shown, flushing valves for pulsed air PL and thinner V and a return valve RF which are connected to the central channel 30a of the color changer.

Since the colors connected to the external color changer are required different times, it may be more convenient to use the external color changer in the out of the EP 1502657 A2 to divide in a manner known per se into channel sections which can be flushed independently of one another. The in Fig. 3 Color changer 12b shown schematically in (b) essentially corresponds to the exemplary embodiment Fig. 2 the aforementioned EP 1502657 A2 , the entire content of which is hereby incorporated into the present description. The two channel sections are designated 30b1 and 30b2 and are connected in series by the controlled shut-off valve 16b. The colors more frequently required are connected to the color valves of section 30b1, designated 1 to 6, while the colors less frequently required are connected to the other color valves of section 30b2. In practice, this results in lower color change losses than in the standard color changer Fig. 3 (a) ,

The in Fig. 3 Color changer 12c shown at (c), which essentially follows the exemplary embodiment Fig. 3 or Fig. 4 the EP 1502657 A2 can correspond, consists of the two parallel channel sections 30c1 and 30c2, which are common to the respective paint, rinse and return valves shown and are connected to the output line of the color changer via a valve 16c1 or 16c2 which can be shut off in a controlled manner. In addition to low color change losses, this color changer has special advantages such as a relatively small footprint and low weight or a larger number of connectable colors for a given size.

If the same colors are connected to the two channel sections 30c1 and 30c2, the color changer is also suitable for A / B operation. This means that the color change time for all selectable colors is always the same.

In the embodiment according to Fig. 2 The color valves for the high-runner colors can be placed almost flush, i.e. free of color loss, on the inner wall of the cylinder of the piston metering device or, if applicable, its intermediate storage container (cf. Fig. 7 ). Fig. 4 on the other hand shows a diagram opposite Fig. 2 somewhat modified embodiment of the invention, in which the color valves FV43 connected to the high-runner lines 43 open into a channel 41 which is common to them and which in turn leads into the cylinder of the piston metering device or, optionally, its intermediate storage container 40. The paint line 45 from the output of the external paint changer 42 for the low-runner colors is also connected to the common channel 41 via a shut-off valve V45 that separates the two paint supply systems for high-runner and low-runner colors. Structurally, the paint line 45 can be an integral part of the usual central channel of the color changer 42 and can merge into the channel 41 or form it (cf. Fig. 8 ). The color changer 42 can, for example, the arrangement shown in the drawing of the color valves F1 to Fn for the n different low-runner colors available, the recirculation valve RF2, the flushing valves V1 and PL1 for thinner or pulsed air, and as shown between the color and Return valves on the one hand and the flush valves on the other hand contain the shut-off valve SPVFW. The low-runner color changer can also follow one of the arrangements Fig. 3 correspond. With pFW is the pressure of the coating material in the central channel of the color changer common to the various low-runner colors and thus the color line 45 measuring color pressure sensor to improve process reliability. The color loss-rich central channel of the color changer 42 only has to be filled with this color when painting with one of the low-runner colors. When painting with one of the high-runner colors, the color changer 42 is separated with the shut-off valve V45.

In Fig. 5 An embodiment of the invention is shown schematically, in which the metering device is formed by a gear metering pump 50, which differs from conventional metering pumps in that it has several inputs to which the color lines 53 for the high-runner colors and parallel to this, the color line 55 from the output of the separate color changer 52 for the low-runner colors are connected via the valve V55. The color valves FV53, with which the inputs for the high-runner colors are provided, can preferably be placed directly on the metering gearwheels of the metering pump 50 with virtually no loss of color. Here, as in the other exemplary embodiments of the invention, the color valves can preferably be designed as needle valves of a conventional type. The shut-off valve V55 for the low-runner colors can be installed in the inlet of the metering pump 50 or upstream of it. The color changer 52 can do that Fig. 4 correspond or one of the color changers Fig. 3 , The low runner color changer according to 4 and 5 can also according to embodiments 1 and 2 be used.

In Fig. 6 An elongated paint container 60 is shown, which is for example the storage container of the known metering device mentioned several times or instead also according to a piston metering device Fig. 2 can act. The four or five high-runner valves FV63, for example, are shown parallel to the container axis next to each other in the end wall 69 of the container 60, possibly next to a further valve VF65 for the low-runner colors. The associated paint lines controlled by these valves can be expediently connected by radial paint connections (not shown) distributed over the circumference of the container. The shut-off valve belonging to the low-runner line (not shown) (V45 in Fig. 4 ) can also be designed differently from the valves FV63 and arranged at a different location. The container 60 can be at least partially circular-cylindrical or with a different cross-section and contain a displaceable piston.

As in Fig. 7 is shown, the high-runner color valves FV 63, which can be signal-controlled needle valve units of the construction shown per se, are preferably so with their needles 73 in the end wall 76 (69 in Fig. 6 ) that the needle ends 78 are at least approximately in the plane of the inside 71 of the end wall 76 when the valve is closed, that is to say they are flush with this plane. The conical valve seat of the color valve FV63 can be seen at 75. For example, one of the paint connections leading radially into the end wall 76 from the circumference for the high-runner paint lines (13 in.) Opened or closed by the paint valves FW63 can be inserted into the opening 77 Fig. 1 ) are used.

Instead of in 6 and 7 The valve arrangement shown is also a radial installation or attachment of the color valves FV63 (valves FV in Fig. 1 respectively. Fig. 2 ) possible, for example similar to one of the embodiments according to 8 to 14 ,

As a rule, the high-runner color valves in the described exemplary embodiments of the invention should be as small as possible so that as many valves as possible can be accommodated in the limited installation space available. The same applies to a built-in or attached valve for connecting low-runner colors (e.g. valve FV1 in Fig. 1 ). The color valves of the removed or separate low-runner color changer, on the other hand, can be built larger. The larger size in itself has the advantage that the flow openings can be larger and the paint flow rate can be correspondingly lower for a given color print and therefore there is less risk of damage to the paint material.

In the Fig. 8 The valve arrangement shown is according to an exemplary embodiment Fig. 4 suitable, in which the five high-runner color valves FV83 shown radially around the central channel 85 of the low-runner color changer (42 in Fig. 4 ) are distributed and adjoin the circumference of the central channel 85 with the ends 88 of their valve needles. The color valves FV83 can be screwed here in a radial plane common to their needle axes into the circumference of a wall element 89 which can form an end wall of the container mentioned or can be attached to the actual end wall. Between the color valves FV83, as shown, the associated color connections 84 for the high-runner colors are distributed over the circumference of the wall element 89. Instead of the star-shaped valve arrangement shown, other arrangements known for example from color changers are also conceivable.

Fig. 9 shows an expedient arrangement of a container 90 with an end wall 69 or 76 containing the high-runner valves and associated radial paint connections 97, for example in accordance with FIG Fig. 7 and with the upstream low-runner color changer 92 in the forearm 91 of a painting robot. The color changer 92 has the modular block design which is typical of color changers in coating systems and is structurally mounted in the immediate vicinity of the end wall 69. A very similar arrangement is also with the embodiment according to Fig. 8 possible. The arrangement of the container 90 next to a (only partially visible) piston metering device 99 and other details can be seen in the drawing and can otherwise be found in FIG EP 1 772 194 A2 described system correspond, so that a more detailed description is unnecessary.

Fig. 10 shows a possibility for the structural arrangement of the high-runner color valves FW103 at the color inlet 105 of a gear metering pump 100 in accordance with the schematic illustration in FIG Fig. 5 , The two metering gear wheels 101 and their drive shaft 102 correspond to conventional designs. The input area of the metering pump according to the invention, however, is only shown incompletely. Needle valve units similar to those in the other exemplary embodiments of the invention can be installed as color valves, for example radially into the end plate unit of the metering pump 100 (not shown). The high-runner color lines controlled by the color valves FW103 are also not shown. The color inlet 105 can be connected to the low-runner color changer according to the invention via a shut-off valve V55 ( Fig. 5 ) can be connected, which can be formed by the valve V105 or arranged elsewhere. The color output of the metering pump 100 is designated by 106.

As has already been mentioned, the installation or attachment of color valves described above in connection with metering devices can, independently of this, be more generally sensible and advantageous for any other container of coating devices. In Fig. 11 such a container 110 is shown, which can be cylindrical as shown or can have another, preferably elongated shape with a longitudinal axis. In the example 18 shown, signal-controlled needle valves FV113 are automatically distributed around the circumference of the container 110, the valve needles 114 of which can lie in a common radial plane transverse to the longitudinal axis of the container 110. For example, the needle valves FV113 can, as shown, be inserted radially into a flange 112 which, for example, encloses the cylindrical wall 111 of the container 110, and penetrate this with their needles 114. When the valve is closed, the ends 115 of the valve needles abutting the valve seat can adjoin the inner surface 116 of the container wall 111 flush or almost flush, so that similarly low color change losses occur as in the exemplary embodiments according to FIG Fig. 7 . Fig. 8 and Fig. 10 , The color lines leading into the container 110 and controlled by the color valves FV113 are not shown.

In this embodiment of the invention, no separate color changer is required 1 to 5 or a central channel of a color changer like 58 in Fig. 8 be provided, in particular if no more colors are required than the existing number of color valves 113. If required, however, it is possible to connect a conventional color changer for additional selectable colors, for example to one of the color valves FV113 or to another automatically controllable input of the container 110.

Coating systems are also conceivable in which the paint inputs of the container 110, for example arranged on a coating robot, are docked in a manner known per se with quick coupling valves to corresponding stationary paint connections of a painting booth.

The embodiment according to Fig. 12 differs from that Fig. 11 essentially only in that the needles 124 of the 12 color valves FV123 in the example shown are not in a radial plane, but rather are inclined relative to the radial plane perpendicular to the container axis, so that the in Fig. 13 recognizable oblique arrangement of the valves FV123 results. Here, too, the valve seats and thus the needle ends when the valve is closed are located in the immediate vicinity of the inner surface 126 of the container 120, with the advantage of correspondingly minimized color losses when changing colors.

If two or more groups of color valves distributed in a ring around the circumference of the container are offset or spaced from one another along the axis of the container, as in Fig. 14 a correspondingly larger number - in the example shown 30 - of valve-controlled color lines for different selectable colors can be connected to the container 140. The two groups of color valves FV143 and FV143 'shown can be as in 12 and 13 be arranged obliquely, advantageously with an opposite angle of inclination with respect to the radial plane. One or each group of color valves can also as in Fig. 11 be arranged in a common radial plane perpendicular to the container axis. Otherwise, the embodiment can be Fig. 14 after those 12 and 13 correspond.

For automatic control of the color valves of the described exemplary embodiments of the invention, electrical or pneumatic signal lines, for example, which are not shown in the drawings, can be connected to the valves in a manner known per se.

In general, the combination of each of the features described in this application with one or more other described features is possible without being restricted to other features and is advantageous depending on the implementation.

Claims (10)

1. Metering device for a coating system for the serial coating of workpieces with different colour shades, wherein by means of the metering device the current amount of applied coating material can be changed in a controlled manner during application, comprising a plurality of paint valves (FV) which are mounted or installed on or in the metering device (10, 20) or a storage container (90) of the metering device and can be controlled by signals for the selection of the coating materials from paint lines (13, 13'),
   wherein the metering device (10, 20, 50)

   a) is or comprises a gear metering pump (50, 100), or

   b) is a piston-type metering means (20) or comprises a piston-type metering means (99), the metering drive of which can be controlled in order to change the piston speed during application, wherein the piston-type metering means (20) or a container (90) arranged upstream thereof has an inlet (E1-E5) for each paint line (13'),

   characterised in that the plurality of paint valves (FV) mounted on or installed in the metering device (10, 20, 50) or a storage container (90) of the metering device are formed by automatically controlled needle valve units (FV63, FV83, FV103).
2. Metering device according to claim 1, characterised in that the needle valve units are so inserted with their needles into a wall of the metering device or the storage container thereof that the needle ends lie at least approximately in the plane of the inside of the wall when the valve is closed.
3. Device according to claim 2, characterised in that the needles (73) of the valves (FV63) pass, parallel to the longitudinal axis of a piston-type metering means or container of the metering device, through an end wall (76) of the piston cylinder (60) or container, and their ends (78) are at least approximately in alignment with the inside of the end wall (76) when the valve is closed.
4. Device according to claim 2, characterised in that the valves (F83) are inserted radially into the periphery of a wall element (89) of a piston cylinder and the ends (88) of their valve needles are approximately flush with an axial central channel (85) when the valve is closed.
5. Metering device according to claim 3 or 4, characterised in that connections (77, 84, 97) for lines controlled by the valves (FV) are inserted radially into the periphery of the end wall (69, 76) or of the wall element (89).
6. Metering device according to any one of the preceding claims, characterised in that the metering device (10) is a piston-type metering means (20) driven by a metering drive and having a cylinder (21) or comprises such a metering means, the regions of which that are separated by the piston (23) each have a plurality of controlled inlets (E1-E5) for coating material with selectable different colour shades and in each case a controlled outlet (A) which can be connected to the outlet valve of an atomiser.
7. Metering device according to claim 6, characterised in that the inlets (E1-E5) of one region are located at or in one end (24) of the cylinder (21) and the inlets of the other region are located in or at the opposite end of the cylinder (21).
8. Metering device according to any one of the preceding claims, characterised in that the paint valves (FV) are distributed over the periphery of the container (110).
9. Metering device according to any one of the preceding claims having a cylinder (21, 60) and a piston which is displaceable therein, characterised in that at least the space of the cylinder (21) that is located on one side of the piston (23) has a plurality of inlets (E1-E5) to each of which there can be connected a paint line (13') of a group of paint lines provided for coating materials of different colours.
10. Use of a metering device according to any one of claims 1 to 9 in a coating system for the serial coating of workpieces with different colour shades, having

    - an atomiser which has an application member for the coating material;

    - the metering device (10, 20) located in the atomiser or in the vicinity thereof and upstream of the application member, with which metering device the current amount of applied coating material can be changed in a controlled manner during application;

    - a group of a plurality of paint lines (13, 13') which supply selectable coating materials with relatively frequently required colour shades to the metering device (10, 20) arranged upstream of the application member, wherein the outlet (11, A) of the metering device (10, 20) is common to the coating materials coming from the paint lines (13, 13') of the group;

    - paint valves (FV) controlled by signals for selecting the coating materials from the paint lines (13, 13') of the first group; and

    - a colour changer (12) arranged at a distance from the atomiser, which colour changer comprises a plurality of paint valves to which there are connected paint lines (14) of a second group for coating material with less frequently required colour shades, and the outlet (15) of which, which is common to the paint lines (14) of the second group,

    - is connected parallel to the paint lines (13, 13') of the first group to the metering device (10, 20) thereof or to a container (90) of the metering device

    - or leads parallel to the metering device (10, 20) to the application member of the atomiser.

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