EP2101925B1 - Coating apparatus comprising a metering device - Google Patents

Description

The invention relates to a coating device for serial coating of workpieces with different shades.

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

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

Piston dispensers, on the other hand, have the advantage of higher metering accuracy by avoiding slippage between the gear pair and the housing of gear metering pumps, and in electrostatic painting equipment in which high voltage insulation between the atomizers and their grounded supply system is required, the discontinuous paint delivery operation of a piston metering device can easily achieve the necessary electrical isolation. Further advantages will be explained later.

As in EP 1 772 194 A2 is described, it may also be useful to precede the Kolbendosierer an electrostatic coating a serving as a lacquer buffer container, which is already filled to reduce the required color change times in a color change with the new color, while still painted with the previous color from the piston dispenser. This storage container can also be defined as part of a metering device in the sense of the invention. To empty the storage container, this may also contain a piston in the cylinder.

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

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

If a sprayer is to apply coating material with a large number of shades, but limited for example by a loop system, and a color change is to take place in the shortest possible time, these are usually referred to as Color changer designated color change valve assemblies in block design (ie used as a mechanical unit), which connect the numerous color inputs via a central channel with the leading to the atomizing color ink outlet. Due to their usual modular design, they are easily adaptable to different numbers of selectable colors. Typical modular color changers for wet paint are for example off DE 198 36 604 A1 and DE 198 46 073 A1 while a basically similar color changer for powder coating in the DE 601 03 281 T2 is described. The rinsing of color changers, for example, deals with the DE 199 51 956 A1 , Such color changer are typically upstream of the known gear or Kolbendosiervorrichtungen or possibly the mentioned paint storage container.

If only a few colors are required, it is also possible to install a color changer in the atomizer, possibly with a downstream metering device ( EP 1 502 658 A1 ) to shorten the path to be washed during a color change from the color changer to the application element, such as the bell cup of a rotary atomizer. For this one has endeavored to construct special space-saving color changer ( EP 1 502 659 B1 ), which is particularly important when color changer in two-way design are required, which are known to have common color supply lines and are connected to the application organ on separate color stretches. The installation of a color change valve arrangement in the atomizer, also referred to in practice as the ICC technique (integrated color changer), has the advantage of substantially reducing color and detergent losses during the color change. In the case of car body painting, the color change losses, for example, from about 45 ml of color per atomizer and color change in conventional color change technology can be reduced to only about 4 ml. A similar Reduction results for the flushing agent losses. In addition, the color change time can typically be halved, typically from 12 seconds to 6 seconds, resulting in an increase in coating machine capacity of about 5-10% or, for example, 30-60 vehicles daily.

A disadvantage of known systems with built-in atomizer color changer the small, limited by the space requirements of the color changer and leading into the atomizer color lines number of selectable shades. Instead of using one of the usual color changer, so a modular color change block with a common output colors for the colors, you can also perform the colors of ring lines through a color hose leading into the atomizer directly through located in the atomizer paint valves the application organ, wherein for each of these colors its own separate metering device can be provided, which consequently does not have to be rinsed in a color change, and the possibility exists to connect a larger number of rarely needed colors (so-called low-runner) via an external color changer, as in the German patent application 10 2006 022 570.8 from 15.05.2006 and in the patent application PCT / EP2007 / 003874 of 02.05.2007, the entire contents of which are hereby incorporated into the present description. The number of selectable frequently required colors (high-runner) is also limited here by the space available in the atomizer, the implementation of the paint tubes by the hand axis of the painting robot and the upstream of dosing devices by the space required for their cultivation on the robot.

The advantage of an unlimited number of applicable color shades offer special color supply systems, in which the colors do not come from ring lines, but in a color mixing room generated and passed over a color changer to the atomizer. However, these systems are relatively complex and have higher color change losses compared to loop systems.

As has already been mentioned, color changers are common in paint shops because, as is well known, they allow rapid changeover from one color to another during the paint shop. But they have the principal disadvantage of unavoidable loss of color when flushing the more or less large central channel at each color change. After optimizing the color losses in, for example, hoses, metering devices, etc., the color changer often represents the element of the coating unit with the greatest single loss. The larger the cross section of the central channel, the greater the color change loss, the greater the amount of color through the color changer in a shorter time To be able to guide, as it may be desired for various reasons (special color supplies, container technology, higher paint quantities, shorter cycle times of successive workpieces, higher viscosities, etc.). In addition, the color change losses increase with the number of connected colors and the resulting length of the central channel, so that the number of hues often has to be limited undesirable.

In order to avoid the color change losses in the usual color changers, working color change systems were developed according to the docking principle, in which the provided for the different shades color lines with mechanically movable valve elements to a line leading to the atomizer can be coupled ( EP 1 245 295 A2 . DE 100 64 065 A1 or DE 601 11 607 T2 ). With these color interfaces, it is possible to achieve a savings in color (typically around 10 ml for each color change) compared to the usual color changers. but they have several practical disadvantages such as elaborate motion control to approach the hitching positions, high maintenance requirements, flushing the interface, drying paint on the interface, leaks, etc.

A relatively good solution to the problem of reducing color losses in a color change is the in the EP 1 502 657 A2 achieved color shifter described, the central channel is divided into independently rinsable sections, wherein the often required high-runner colors, ie the colors are connected with high consumption volume at the front end located at the color output, while rare at the rear, the color output facing away required colors (low-runner) are connected. While the often needed front section is always flushed independently of the rear section, the less frequently needed section can be flushed together with the other section. Since in a color change is no longer flushed as in conventional color changers always the entire central channel, resulting in lower losses of paint and rinsing liquid. But even these remaining color change losses are undesirable, especially for colors often required.

After the exit of color changers usually a color pressure regulator is arranged, which provide for a form 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 rinsed with every color change.

WO 02/07899 A discloses a coating system with an atomizer replaceably mountable on a robotic arm, which contains a paint container and, during operation, of its Ink supply system is disconnected. To fill the paint container this can be connected in a stationary filling either to separate color change modules for frequently or less frequently required colors.

EP 0338871 A1 discloses a stationary color change system having a group of primary color changers connected upstream of a secondary color changer and connected at their inputs to respective colors in the order of color frequency. This is intended to reduce the frequency of rinses required for a color change.

EP 1360996 A1 describes a color distribution system, which is used for potential separation, between a color changer stationarily arranged outside the spray booth and high-voltage atomizers. This system contains two alternating piston feeders with servomotors as metering drive.

JP 06246200 A discloses a paint supply system for a nebulizer, which are preceded by a color common line with a pump two parallel color changer, whereby the length to be purged in a color change of the respective color changer channel is reduced.

EP 1134027 A2 discloses a potential separation system for an electrostatic sprayer, which consists of a flexible hose paint supply line to the collection channel of a color changer to the paint valves lines for the available colors are connected. In the line is a piston which can be displaced like a pig and which is pushed through the color changer and the line in the direction of the atomizer in order to convey the paint. The speed of movement of the piston can be controlled by a metering device.

Based on the described prior art such as the EP 1 502 658 A1 It is an object of the invention is a coating device or usable for it Specify devices for the coating of workpieces in particular with different frequently required shades that allow a color change with minimal or little color, detergent and time losses.

This object is solved by the features of the claims.

For example, in the automotive industry currently limited to about 70 or 80% of the production volume to about 7 shades or less. However, due to the direct connection of these frequently required colors to the automatically controlled metering device, according to the invention, the color change losses of paint and detergent in the correspondingly frequent change of these high-runner colors and at the same time the necessary color change times over the advantages of the ICC technology described above on one Minimum, without limiting the total number of selectable hues, including many less-needed or low-runner colors where color change losses are less serious because of 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, ie for the most frequently required colors or, equally, for the colors with the largest production volume, its typical color change losses of material and Time. In addition, the color change losses of a separate typical color changer for less frequently required colors are reduced because its length is shortened by eliminating the most commonly needed colors accordingly, if instead a correspondingly larger number of selectable colors should be connected.

The least is the color-change loss of the high-runner colors when both the dosing device and the color lines required for these colors are placed in the nebulizer.

In direct connection of all color lines to each input of the metering device in a color change only the colors common short way from the metering device to the application organ such. B. the bell cup of a rotary atomizer to be rinsed. Preferably, the associated, controlled by external signals for color selection color valves are directly attached to the metering or built into this, but the color valves could also in the known manner ( EP 1502658 A1 ) form a typical color changer upstream of the metering device with a central output channel common to the colors.

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

In other cases, it may be more convenient to arrange the metering device and / or the paint valves, possibly in a conventional color changer, although also in the vicinity of the atomizer, but a little further away from him, for example, in or on an arm of the atomizer moving Coating robot or other programmable motion machine. In particular, it may be appropriate, according to the mentioned EP 1 772 194 A2 to accommodate existing from a piston dispenser with upstream paint storage container metering device in the forearm of a painting robot.

On the other hand, the color changer provided for possibly many but less frequently required shades is always arranged separately and further away from the atomizer, preferably in or on one arm of the coating robot or the like. The closer the color changer is to the nebulizer, the less the change in color is, but for a larger number of colors, because of its space requirements and for dynamic and other practical reasons, it usually can not be in or on the nebulizer before the wrist the paint robot od. Like. Are arranged, as is possible in many cases for the high-runner color valves, but possibly 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, ie in the second robot arm or moving along (on the so-called axis 7) or even outside the painting robot. Color losses in a color change can be, for example, in this case, but also for the high-runner ink supply described by those skilled in the per se known additional measures such as in particular the pig technology in conjunction with pushing back the remaining in the line colors to the supply system ("Reflow") and / or almost complete consumption of each color in the line when applying ("pushout") avoid.

The output of the separate color changer for less frequently required colors is preferably connected in parallel to the color lines of the most frequently required high-runner colors to its own additional input of the metering device or possibly 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 in a largely arbitrary distance outside the atomizer. d. H. usually at the main needle valve.

Preferably, parallel to the separate color changer for color tones less frequently required, a further matching color changer is provided, which is connected to color lines for the same color tones. This can avoid unwanted time losses during color change, because during the rinsing of a dye changer and its output line and during the preparation for the next color (possibly including reflow) of the atomizer can be supplied from the other color changer. This alternating ink supply is usually referred to as A / B operation (cf. EP 1314483 A ). The two matching supply branches (A and B) are connected parallel to each other to the atomizer, in preferred embodiments of the invention described here to two inputs of the metering device (possibly their storage container) or otherwise via its own metering device to the Hauptnädelventil the atomizer. But A / B operation is also for the invention High-runner ink supply possible, for which then parallel to the arrangement of the metering device and the controlled color valves frequently required shades a matching arrangement of a metering device and controlled color valves is provided, in which case the color valves of the two arrangements of color lines for the same Shades are connected. Instead, a single, but designed for alternating operation piston feeder in principle according to EP 1666158 A2 used, that is, a motor-driven piston dispenser with a cylinder whose separate areas through the piston each have a plurality of controlled inputs for the selectable different shades and one connected to the main needle or other output valve of the atomizer controlled output.

The or (for A / B operation) any color changer for less than the z. B. 7 or less Fiigh Runner colors required colors may conveniently contain at least two line sections, open into each of which several controlled paint valves for coating materials with selectable different shades, and of which at least one line section is irrigated independently of at least one other line section, the Line sections are connected by a controlled shut-off valve with each other and / or with an output line of the color changer. Such color changer are in itself from the EP 1502657 A2 Known and allow to reduce the color change losses meaningful further differentiation between different colors often required, with less frequently needed colors are connected to the further away from the color output one line section of the color changer and the other colors at its located at the color output other line section.

If two separate parallel metering devices are provided in the atomizer or in its vicinity, these metering devices can also work simultaneously to supply the application organ with two components of a coating material, such as 2K lacquers, coming from separate supply lines.

According to a particular preferred aspect of the invention, which in some cases may also be useful and advantageous without the above described feature of a less frequently used color changer remote from the nebulizer, the dosing device preferably installed or attached in the nebulizer or in its vicinity a piston dispenser with an automatically controllable for changing the piston speed during the application dosing drive, for which one of the known from the prior art constructions can be used. However, the piston dispenser according to the invention or possibly its upstream storage container has in contrast to the known constructions not only one or at most (as in the case of the mentioned EP 1666158 ) two inputs, but for each of the selectable frequently required shades at least one input and at least one common for the feedable color materials output. In addition to the low material and time losses during color change, a piston dispenser has particular advantages over gear metering pumps and other metering systems such as better flushability with less flushing effort and the possibility of pressing back the colors (reflow) in the supply system such. B. ring lines directly over the paint valves, without having to be filled for a color changer and the connection between the dispenser and the color changer. Another essential advantage of the piston dispenser is that it does not have a color pressure regulator needed, in contrast to currently available gear metering pumps, which usually would have to be preceded by a separate color pressure regulator for reasons of metering accuracy for each connected color line. The piston dispenser avoids the disadvantages of pressure regulators such as costs, color losses during color change, space requirements and weight loading of the robot axes.

U. a. To reduce the color change losses as well as for space and construction reasons, it is particularly useful if the controlled by signals for color selection color valves of the high-runner color lines are attached to the metering or constructive integrated into this. In the case of a piston dispenser or an upstream piston cylinder (which is to understand a container with any, not circular cross-section) so at least the located on one side of the piston chamber of the piston cylinder can have a plurality of inputs for the color lines of different colored coating materials, the inputs preferably have valves built into the cylinder or attached to the cylinder, which are controllable by signals for selecting the coating materials that can be supplied to the piston dispenser. Such a piston dispenser, with or without an upstream storage container, may also be useful and advantageous for itself and independently of the coating device described here, ie also in any other ink supply systems including systems in which the piston dispenser is not located in or in the atomizer. The same applies to the above-mentioned double-acting piston dispenser according to the EP 1666158 A2 in which the inputs of the one region of the cylinder intended for the different selectable colors come to rest on or in the one end of the cylinder and the inlets of the other region contact or can be located in the opposite front end of the cylinder.

According to another aspect of the invention, which may also be convenient and advantageous on its own and without the feature of arranging color changers in or more or less far from the atomizer, the color-change valves may be incorporated into a gear metering pump of conventional type be attached to the metering pump.

According to a further aspect of the invention, which may also be convenient and advantageous by itself and without other of the described features, the paint valves may also be placed in or on a container of a coating apparatus such as e.g. a coating robot on or be grown, which does not serve for dosing, but in a conventional manner other purposes such as as an intermediate or reservoir.

The number of on or in a metering device or a container of a coating device built or attached color valves for a corresponding number of color inputs depends on the particular case, but is usually 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 will be 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 dispenser 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 expedient structural realization of the metering according to Fig. 2 ;

Fig. 7

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

Fig. 8

an expedient structural realization of the metering according to Fig. 4 ;

Fig. 9

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

Fig. 10

an appropriate structural realization of the metering device and its valves according to 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 according to Fig. 11 ;

Fig. 13

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

Fig. 14

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

In the Fig. 1 Coating device shown comprises a metering device 10, at the output 11 of the usual main needle valve od. The like. A (not shown) atomizer for color material such as an electrostatic rotary atomizer or air atomizer is connected. The output 11 is a plurality, in the illustrated example, six color inputs of the metering device 11 in common, each having a color selection automatically controlled by the parent control program color valve FV1, FV2, etc. to FV6. The metering device 10 can be of any type per se, that is one of the known for coating systems metering systems including piston dispensers and gear metering or working with color printing and ink quantity control systems, etc. Volumetric metering devices and in particular piston dispensers are preferred in the invention.

In the illustrated example, the color lines 13 for the most frequently used in coating operation or high-runner colors (labeled 2 to 6) connected to the paint valves FV2 to FV6 of the metering device 10, which fed, for example, as spur lines of the usual in coating lines ring lines be or even be designed as a loop. One of the color valves, here FV1, in contrast, is connected via a color line 15 to the output of an external color changer 12 and serves to separate the high-runner color-changing region from the low-runner color changer 12. The color changer 12 can have explained above conventional modular block design with a central channel to which the paint lines 14 are connected via the color valves of the color changer for less frequently needed or low-runner colors. Preferred embodiments of the color changer 12 will be described below with reference to FIG Fig. 3 described.

As already explained, the metering device 10 and / or the paint valves FV1 to FV6 can preferably be located in the atomizer or movable with it in its vicinity, in particular between the atomizer and the wrist of a painting robot or in its forearm. As has already been mentioned, the paint valves are preferably attached to the metering device 10 (piston dispenser, storage container, metering pump or, if appropriate, the measuring cell or the color pressure regulator known per se metering systems, etc.) or incorporated therein. By contrast, the external color changer 12 can be located at a location which, although it is intended to be as close as possible to the atomizer in terms of color change losses, but otherwise is largely arbitrary. For dynamic and space reasons, for example, a location on or in the rear robot arm may be expedient if an arrangement further down can not be realized.

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

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

As also in the cited patent applications 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 be transmitted floating in or out of the atomizer, for example, optically or via radio. In this case, in particular, the external signals controlling the metering drive can also be transmitted together with other signals via a common cable or radio link, etc.

According to a particular feature, which is also advantageous regardless of the high-runner ink supply described herein can be realized, the operation of the usual main needle valve or other output or main valve of the atomizer can be controlled by the pressure generated at the output (11) of the main valve upstream of the metering device. The main valve is thus opened by the pressure of the metering device, as soon as and as long as a corresponding pressure is present, and automatically closed in the absence of pressure. The principle of operation here corresponds to that of a paint control system commonly used in coating systems, as described, for example, in DÜRR / BEHR Technical Handbook, 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 entire contents of which are hereby incorporated into the disclosure of the present application. Such a color pressure regulator (which need not be a "regulator" in the sense of a closed loop) according to the invention can in principle replace the piston drive conventional main needle valves and its external control, the valve is not opened by control air, but by the color printing itself. Accordingly, the main valve of the atomizer or other application device preferably consist of a needle valve or a ball or other valve for the coating material held by spring force in the closed position and opened by acting against the spring force pressure of the coating material, for example via a membrane becomes as soon as this pressure reaches a certain value, which 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 described metering device. By this (indirect) automation of the main needle control by the metering eliminates the very complex setting of the main needle circuit conventional atomizers whose main needle valve is known only by external signals the program control of the coating system is opened and closed (see, eg EP 1245291 B1 ).

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

According to the invention, however, the piston dispenser 20 has a plurality of, in the illustrated example, five color inputs E1 to E5, each having a color valve FV1 'to FV5' and thus connected to one of five color lines 13 'for different high-runner colors. An additional, also provided with a valve VV input E6 is provided for introducing a serving as a rinsing agent diluter V and also for cleaning it cylinder 21 serving pulse air PL. Further, the cylinder 21 has an output A with an output valve VA, to which a leading to the main needle or output valve of the atomizer output line of the piston meter is connected.

The paint valves FV are preferably mounted on or built into the cylinder bottom 24 of the piston dispenser, as indicated by the dashed line 24 '. Accordingly can also be the purge valve VV and / or the output valve FA attached or installed.

When the piston dispenser 20 of the Fig. 2 as dosing device 10 of the basis of Fig. 1 one of the color inputs such as E1 to E5 of the piston dispenser also (instead of a high-runner color line) to that of an external color changer, so for example by the color changer 12 in Fig. 1 coming color line for less frequently needed shades be connected. Instead, however, could also lead the output line of an external color changer bypassing the piston meter 20 to the output valve of the atomizer.

In the context of the invention, it may be in the element 20 in Fig. 2 also, for example, according to a paint storage container upstream of the actual piston dispenser EP 1 772 194 A2 act, the piston is usually not driven by an electric motor, but in the filling direction of the coating material and in the discharge direction of a pressure medium such as compressed air.

In a further development of the piston dispenser 20 for alternate operation of the cylinder areas separated by the piston 23 according to FIG 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 bottom of the piston dispenser opposite the cylinder bottom 24.

The provided in the preferred embodiments of the invention external color changer 12 ( Fig. 1 ) for less needed colors could be the in Fig. 3 at (a) have shown schematically known design, as for example DE 19836604 A1 . DE 19846073 A1 or DE 19951956 A1 known per se. It consists essentially of color valves for the illustrated example twenty-four different colors, purge valves for pulse air PL and thinner V and a recirculation valve RF, which are connected to the central channel 30a of the color changer.

Since the colors connected to the external color changer are in turn required differently often, however, it may be more appropriate to use the external color changer in the EP 1502657 A2 to divide into independently rinsable channel sections known per se. The in Fig. 3 at (b) shown schematically color changer 12b substantially corresponds to the embodiment according to Fig. 2 said EP 1502657 A2 the entire contents of which are hereby incorporated into the present description. The two channel sections are denoted by 30b1 and 30b2 and connected in series by the controlled shut-off valve 16b. To the designated with 1 to 6 color valves of the section 30b1 the more frequently required colors are connected to the other color valves of section 30b2, however, the less frequently required colors. This results in practice lower color change losses than in the standard color changer according to Fig. 3 (a) ,

The in Fig. 3 at (c) shown color changer 12c, which is substantially the embodiment according to Fig. 3 or Fig. 4 of the EP 1502657 A2 can correspond, consists of the two parallel channel sections 30c1 and 30c2, which are common to the illustrated color, flushing and return valves and are connected via a respective controllable shut-off valve 16c1 and 16c2 with the output line of the color changer. This color changer has particular advantages in addition to low color change losses such as 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 makes it possible to achieve a consistently short color change time for all selectable colors.

According to the embodiment Fig. 2 For example, the color valves for the high-runner colors can be placed almost flush, ie without loss of color, on the inner wall of the cylinder of the piston dispenser or, if appropriate, of its intermediate storage container (cf. Fig. 7 ). Fig. 4 shows a schematic opposite Fig. 2 slightly modified embodiment of the invention, in which the color valves FV43 connected to the high-runner lines 43 open into a common channel 41, which in turn leads into the cylinder of the piston dispenser or possibly its intermediate storage container 40. To the common channel 41, the color line 45 is connected from the output of the external color changer 42 for the low-runner colors on one of the two paint supply systems for high-runner or low-runner colors separating shut-off valve V45. Structurally, the color line 45 may be an integral part of the usual central channel of the color changer 42 and pass into the channel 41 or form this (see. Fig. 8 ). The color changer 42 may be, for example, the arrangement to be taken from the color valves F1 to Fn for the n different available low-runner colors, the recirculation valve RF2, the purge valves V1 and PL1 for thinner or pulse air and the illustration between the color and Return valves on the one hand and the purge valves on the other hand arranged shut-off valve SPVFW included. 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 common low-runner colors common channel of the color changer and thus the color line 45 measuring color pressure sensor to improve the process reliability. The color loss-rich central channel of the color changer 42 only has to be filled with this color during painting with one of the low-runner colors. When painting with one of the high-runner colors, the color changer 42 is disconnected with the shut-off valve V45.

In Fig. 5 schematically an embodiment of the invention is shown, in which the metering device is formed by a Zahnraddosierpumpe 50, which differs from conventional metering pumps in that it has several inputs to which via respective color valves FV53 the color lines 53 for the high-runner colors and connected in parallel thereto via the valve V55, the color line 55 from the output of the separate color changer 52 for the low-runner colors. The color valves FV53, with which the inputs for the high-runner colors are provided, can preferably be placed directly on the metering gear wheels of the metering pump 50 almost without loss of color. Here as well as in the other embodiments of the invention, the paint valves may preferably be designed as needle valves per se conventional type. The shut-off valve V55 for the low-runner colors may be installed in or upstream of the input of the metering pump 50. The color changer 52 can after Fig. 4 match or even one of the color changers after Fig. 3 , The low-runner color changer according to 4 and FIG. 5 can also for embodiments according to Fig. 1 and Fig. 2 be used.

In Fig. 6 an elongated paint container 60 is shown, which may be, for example, the storage container of the aforementioned known metering device or instead also according to a piston dispenser Fig. 2 can act. The example, four or five high-runner valves FV63 are shown as parallel to the container axis side by side in the end wall 69 of the container 60, possibly in addition to another valve VF65 for the low-runner colors. The associated color lines controlled by these valves may conveniently be connected by radial paint connections (not shown) distributed over the circumference of the container. The shut-off valve (V45 in.) Belonging to the low-runner line (not shown) Fig. 4 ) may also be designed differently than the valves FV63 and be arranged elsewhere. The container 60 may 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, the signal-controlled needle valve units of the illustrated per se conventional design can be, preferably so with their needles 73 in the end wall 76 (69 in Fig. 6 ) used, the needle ends 78 are at least approximately in the plane of the inner side 71 of the end wall 76 with the valve closed, so aligned with this level. At 75, the conical valve seat of the color valve FV63 can be seen. For example, in the opening 77, one of the radially extending from the periphery in the end wall 76 color ports for the opened or closed by the color valves FW63 high-runner color lines (13 in Fig. 1 ) are used.

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

In general, the high-color runner valves in the described embodiments of the invention should be as small as possible so that as many valves as possible can be accommodated in the available limited space. The same applies to a built-in or attached valve for the connection of low-runner colors (eg valve FV1 in Fig. 1 ). The color valves of the remote or separate low-runner color changer, however, can be built larger. The larger size has the advantage that with a given color printing, the flow openings larger and the Lackfließgeschwindigkeit can be correspondingly smaller and therefore there is a lower risk of damage to the paint material.

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

Fig. 9 shows a convenient arrangement of a container 90 with the high-Runner valves and associated radial paint connections 97 containing end wall 69 and 76, for example according to 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 typical of color changers in coating systems and is constructively mounted in close proximity to 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 dispenser 99 and other details are shown in the drawing and can otherwise the in EP 1 772 194 A2 described system, 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 paint inlet 105 of a gear-wheel metering pump 100 according to the schematic representation in Fig. 5 , The two Dosierzahnräder 101 and the drive shaft 102 correspond to conventional constructions. The input range of the metering pump according to the invention, however, is shown only incomplete. As color valves similar needle valve units as in the other Ausführungsbei play the invention can be installed, for example as shown radially into the front plate unit of the metering pump 100, not shown. Also controlled by the color valves FW103 high-runner color lines are not shown. The color input 105 can be connected to the separate low-runner color changer according to the invention via a shut-off valve V55 (FIG. Fig. 5 ), which may be formed by the valve V105 or disposed elsewhere. 106 designates the color output of the metering pump 100.

As has already been mentioned, the incorporation or installation of color valves described above in connection with metering devices can independently of this be more appropriate and advantageous for any other containers of coating devices. In Fig. 11 if such a container 110 is shown, which may be cylindrical as shown or may have another, preferably elongated shape with a longitudinal axis. Automatically signal-controlled needle valves FV113 are distributed around the circumference of the container 110 in the illustrated example 18, whose valve needles 114 can lie transversely to the longitudinal axis of the container 110 in a common radial plane. For example, as shown, the needle valves FV113 may be inserted radially into a flange 112 enclosing, for example, the cylindrical wall 111 of the container 110 and penetrating it with its needles 114. When the valve is closed, the ends 115 of the valve needles resting against the valve seat can be flush or nearly flush with the inner surface 116 of the container wall 111, so that similarly small color change losses occur, as in the exemplary embodiments, for example Fig. 7 . Fig. 8 and Fig. 10 , The leading into the container 110, controlled by the color valves FV113 color lines are not shown.

In this embodiment of the invention no separate color changer according to Fig. 1 to Fig. 5 or a central channel of a color changer such as 58 in Fig. 8 However, if necessary, the connection of a conventional color changer for additional selectable colors is possible, 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 color inputs of the container 110 arranged, for example, on a coating robot are docked in a manner known per se with quick-coupling valves to corresponding stationary paint connections of a paint booth.

The embodiment according to Fig. 12 is different from that Fig. 11 essentially only in that the needles 124 of the illustrated example 12 color valves FV123 are not in a radial plane, but are arranged inclined relative to the tank axis perpendicular to the radial plane, so that the in Fig. 13 recognizable oblique arrangement of valves FV123 results. Again, the valve seats and thus with the valve closed, the needle ends in the immediate vicinity of the inner surface 126 of the container 120 with the advantage correspondingly minimized color loss during color change.

By displacing or spacing two or more groups of color valves distributed annularly around the periphery of the container along the container axis, as in FIG Fig. 14 is shown, you can connect a correspondingly larger number - in the illustrated example 30 - of valve-controlled paint lines for different selectable colors to the container 140. The illustrated two groups of color valves FV143 and FV143 'can, as in FIGS. 12 and 13 be arranged obliquely, expediently with mutually opposite inclination angle with respect to the radial plane. One or each group of color valves may also be as in Fig. 11 be arranged in a common radial plane perpendicular to the container axis. Incidentally, the embodiment according to Fig. 14 those after FIGS. 12 and 13 correspond.

For automatic control of the paint valves of the described embodiments of the invention may be connected to the valves in a conventional manner, for example, electrical or pneumatic signal lines, which are not shown in the drawings.

Claims (15)

1. A coating apparatus for the serial coating of workpieces with different colours, comprising

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

   - a metering device (10, 20), particularly provided within or in the vicinity of the atomiser, upstream of the application member, with which the instantaneous quantity of the applied coating material is controllably adjustable during application;

   - a first group of several paint lines (13, 13'), which supply selectable coating materials with relatively frequently required different colours to the metering device (10,20) upstream of the application member, the outlet (11, A) of the metering device (10, 20) being shared by the coating materials coming from the paint lines (13, 13') of the first group; and

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

   - the controlled paint valves (FV) of the first group of paint lines (13, 13') being arranged in the atomiser or fixedly attached to the atomiser so as to be movable therewith or arranged between the atomiser and a wrist joint or in a mobile arm of a program-controlled automatic motion machine moving the atomiser;

   - and a colour changer (12) arranged at a distance from the atomiser being provided, which contains a plurality of paint valves, to each of which paint lines (14) of a second group for coating material having less frequently required colours is connected, and the outlet (15) of which shared by the paint lines (14) of the second group

   - being connected in 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 leading to the application member of the atomiser in parallel to the metering device (10, 20).
2. A coating apparatus in accordance with claim 1, characterised in

   a) that the metering device (10) is a plunger-type metering mechanism (20) or contains a plunger-type metering mechanism (99), the driving motor thereof being controllable to change the piston speed during the application, and that the plunger-type metering mechanism (20) or a container (90) positioned upstream thereof has a respective inlet (E1-E5) for each paint line (13') of the first group, or

   b) that the metering device is or contains a gear metering pump (40, 100).
3. The coating apparatus in accordance with one of the previous claims, characterised in

   a) that the paint lines (13) of the first group each run into the metering device (10, 20) via a respective paint valve (FV) which is controllable for paint selection or are connected to a common line leading into the metering device, and/or

   b) that the metering device (10, 20) is arranged in the atomiser or fixedly attached to the atomiser so as to be movable therewith, and/or

   c) that the metering device (10, 20, 90) is arranged between the atomiser and a wrist joint or in a mobile arm (91) of a coating robot or another program-controlled automatic motion machine moving the atomiser.
4. The coating apparatus in accordance with one of the previous claims, characterised in

   a) that the colour changer (12, 92) of the second group is arranged in or on an arm (91) of a coating robot or another program-controlled automatic motion machine moving the atomiser, and/or

   b) that the colour changer (12b, 12c) of the second group contains at least two line sections (30bl, 30b2; 30c1, 30c2), into each of which discharge several controlled paint valves for coating materials with selectable different colours, and of which at least one line section is flushable independently from at least one other pipe section, the line sections being connected to each other and/or to an output line of the colour changer (12b, 12c) by a controlled lockable valve (16b; 16c1, 16c2).
5. The coating apparatus in accordance with one of the previous claims, characterised in that the paint valves (FV) of the paint lines of the first group, which are controlled by paint selection signals, are attached on or installed in the metering device (10, 20) or a storage vessel (90) of the metering device.
6. The coating apparatus in accordance with one of the previous claims, characterised in that an electrical drive motor of the metering device (10, 20) is arranged in the atomiser or fixedly attached to it.
7. The coating apparatus in accordance with one of the previous claims with an electrostatic atomiser, characterised in

   a) that the metering device (10, 20) and/or an electric metering drive in operation are on the high voltage potential of the atomiser, the metering drive being fed potential-separatedly by an isolating transformer provided in the atomiser or in its vicinity, which transformer contains a high voltage insulation section, and/or

   b) that in the atomiser or in its vicinity, two separated parallel metering devices (10, 20) are provided, operating alternatingly, selectively or simultaneously, and or

   c) that for A/B operation a further corresponding arrangement of a metering device and controlled paint valves is provided parallel to the arrangement of the metering device (10, 20) and the controlled paint valves (FV) of the frequently required colours and/or a further corresponding colour changer is provided parallel to the colour changer (12) of the second goup, the paint valves of both arrangements or both colour changers each being connected to paint lines for the same colours.
8. The coating device in accordance with one of the previous claims, characterised in that the metering device (10) is a motor-driven plunger-type metering mechanism (20) with a cylinder (21) or contains such a metering device, whose areas separated by the piston (23) have each a plurality of controlled inlets (E1-E5) for coating material having selectable variable colours and each a controlled outlet (A) connected to the outlet valve of the atomiser.
9. The coating apparatus in accordance with claim 8, characterised in that the inlets (E1-E5) of one of the areas are located in or on the one front end (24) of the cylinder (21) and the inlets of the other area are located on or in the opposing front end of the cylinder (21).
10. The coating apparatus in accordance with one of the previous claims comprising a container, characterised in that the container (60, 110) has a plurality of inlets,to each of which is connected or connectable one of several paint lines for coating material of different colours, and that the inlets have valves (FV) installed in or attached on the container, which are controllable by signals for selecting the coating material feedable to the container.
11. The coating apparatus in accordance with claim 10, characterised in that the valves (FV) are distributed around the circumference of the container (110).
12. The coating apparatus in accordance with one of the previous claims, with a cylinder (21, 60) and a piston being slideable within the same, characterised in

    a) that at least the space of the cylinder (21) on one side of the piston (23) has a plurality of inlets (E1-E5), to each of which a paint line (13') of a group of paint lines provided for coating materials of different colours is connected or connectable, and/or

    b) that the inlets (E1-E5) include valves (FV) installed in the cylinder (21) or attached on the cylinder (21), which are controllable by signals used to select the coating materials feedable to the metering device (20), and/or

    c) that the valves (FV) comprise automatically controlled needle valve units (FV63, FV83).
13. The coating apparatus in accordance with claim 12, characterised in

    a) that the needles (73) of the valves (FV63) extend through an end wall (76) of the piston cylinder (60) or the container in parallel to the longitudinal axis of the piston cylinder or the container, and when the valve is closed, the needle ends (78) are aligned at least approximately to the inner side (71) of the end wall (76), or

    b) that the valves (FV83) are installed radially in the circumference of a wall element (89) of the piston cylinder and when the valve is closed, the ends (88) of their valve needles are nearly flush with an axial central channel (85), and/or

    c) that connections (77, 84, 97) for lines controlled by the valve (FV) are installed radially in the circumference of the end wall (69, 76) or of the wall element (89).
14. The coating apparatus in accordance with one of the previous claims, characterized by an atomiser with a main valve for the coating material, which remains in the closed position through spring pressure and is opened by the pressure a control medium at a control inlet, working against the spring pressure, the control inlet of the main valve being pressurised by the pressure of the coating material.
15. The coating apparatus in accordance with claim 14, characterised in

    a) that the main valve is opened by a membrane pressurised by the pressure of the coating material, and/or

    b) the control inlet of the main valve is connected to the outlet of the metering device for the coating material.

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