EP1142649B1 - Process and apparatus for coating - Google Patents

Abstract

A process for coating, in particular for painting, individual objects or small-series batches with a small quantity of paint uses a plurality of atomizers 2, 3, 4 connected one behind the other to a main supply line 5, at one end/start 6 of which a paint-supply unit 7 is arranged. Only the quantity of paint which is required for the painting job and an additional minimal residual quantity are introduced into the main supply line 5, irrespective of the length and the actual capacity of the main supply line 5, e.g. a paint quantity less than the volume capacity of the main supply line. The contents of the main supply line 5 are forced, by at least one pig 32, which is pushed through the line 5 by a pushing medium, to the atomizers 2, 3, 4, and the contents are then at least substantially completely discharged there.

Description

The invention relates to a method and a device for coating and in particular for painting individual objects or small series with a small amount of paint with the aid of a plurality of successively arranged atomizers according to the preamble of claim 1.

For supplying various atomizers, for example in a Lakkierkabine it is known to lay a so-called "loop" along the cabin or around them. This ring line usually begins at a paint reservoir, from which the paint material is fed by means of a feed pump in the loop and it also ends in this paint reservoir, in which the pumped paint flows back again. The line is equipped with the necessary fittings for proper operation to maintain a constant paint pressure.

From this ring line branch stubs from each spray point, which can be supplied with manual spray guns or automatic paint sprayer. If a large number of ring lines for different shades parallel to each other before, the individual shades can be performed on a so-called "automatic color changer", which supplies the atomizer each required color over a single line. The majority of these shades, which are usually processed in a plant, are so-called standard shades.

However, if, in deviation from the default held Farbton program individual shades, for example, in special series, are available at short notice, the special color must be replaced in one of the existing loops against the standard color or it can be kept a single loop only for special colors in the then a quick change of the introduced shades is possible.

Often there is also the desire to paint only individual workpieces or very small quantities of workpieces with a special color.

For this purpose, it is known to fill one of the usual ring lines with the special color, there are cases in which a larger Paint quantity for filling the line is required, as would be necessary for the actual painting of the workpiece.

It is therefore also known to position small quantity containers at different spray locations along a paint booth in order to supply the atomizers with only short pipe sections. This alternative to a cumbersome and short-term filling of a loop is common practice.

Are known from the DE patent application 198 17 377 , A method and apparatus for supplying paint to atomizers which are connected by means of the paint-carrying lines to a paint supply station, wherein after completion of the painting process on at least one of the atomizer at least a part of the paint in its line to another Atomizer is funded by a Molchsytem.

The invention has for its object, regardless of the circumstances, a particularly useful method and apparatus for coating and in particular for painting of individual items or small series with small amounts of paint on several successively arranged atomizers indicate so that only the actual required amount of paint and in addition a System-related, minimum residual amount needed.

To solve this problem, the invention provides with the features of claim 1, that only the total amount of paint required and in addition a minimum residual amount in the main supply line regardless of their length and their actual capacity are introduced and that located in the main supply line paint amount using at least one pig, which acts on a sliding medium, is pressed to the or to be operated atomizers and there completely or almost completely discharged.

The required amount of paint is basically known and the same applies to the capacity of the lines. Taking into account these sizes only as much coating agent is fed into the main supply line and either immediately applied to one or more atomizers on the or the workpieces or applied only when the pig and the moving sliding medium in the main supply line are already there. This makes it possible to completely consume the filled coating agent without having to discard and discard significant residual amounts.

In general, the atomizers are located at the free ends of stubs, whose other end is arranged on a color changer, through which the main supply line is guided.

In order to make full use of the contents of these stubs, further development of the invention provides that the contents of the stub line are also emptied before completion of the coating also with the aid of a pig in the direction of atomizer or after completion of the coating towards color changer and main supply line.

To carry out the method, sufficient metering and / or control and / or measuring devices are provided which measure the essential parameters of the volume flow at the respectively relevant points and control the device.

Further features of the invention will become apparent from dependent claims and the description in conjunction with the drawings.

Fig. 1:

ein Fließschema der Vorrichtung;

Fig. 2:

ein Fließschema einer abgewandelten Ausführungsform;

Fig. 3:

ein Fließschema eines dritten Ausführungsbeispieles;

Fig. 4:

in größerem Maßstab eine Lackversorgungseinheit;

Fig. 5:

eine abgewandelte Lackversorgungseinheit und

Fig. 6:

ein weiteres Ausführungsbeispiel einer Lackversorgungseinheit.

The invention will be described in more detail below with reference to embodiments shown in the drawing. Showing:

Fig. 1:

a flow chart of the device;

Fig. 2:

a flowchart of a modified embodiment;

3:

a flowchart of a third embodiment;

4:

on a larger scale, a paint supply unit;

Fig. 5:

a modified paint supply unit and

Fig. 6:

a further embodiment of a paint supply unit.

A device 1 for coating or painting of individual objects or small series with a small amount of paint on a plurality of successively arranged atomizers 2, 3 and 4 comprises a main supply line 5 and arranged at one end of 6 paint supply unit 7. The paint supply unit 7 is at a central location, for example, arranged outside of a paint booth and optionally includes a mobile, movable receiving structure (trolley) for a paint reservoir 8. To the paint supply unit 7 belong according to the in Fig. 1 illustrated embodiment, a paint delivery pump 9 and a quantity measuring device 10. In Fig. 1 the quantity measuring device 10 is shown as a balance, which transmits via a signal line the amount contained in the paint reservoir 8 a belonging to the device 1, not of interest here control.

Modifications of the paint supply unit 7 are in the FIGS. 4 to 6 represented, wherein basically the same parts have the same reference numerals and additional letter indices.

The paint supply unit 7a according to Fig. 4 comprises a paint reservoir 8a from which the paint material is conveyed by means of a volumetric pump 12a, for example a gear pump, driven by an electric motor 11a. The rotational frequency of the motor or the quantity of paint delivered by the pump 12a is communicated to the higher-level control. An agitator driven by a motor 13a keeps the paint in the paint reservoir 8a in motion.

The paint supply unit 7b according to Fig. 5 comprises a pressure vessel 15b, from which the paint is pressed by applying an overpressure in the main supply line 5b. In the main supply line 5b, a measuring cell 16b, for example a gear measuring cell or an induction measuring device is integrated, with which the amount of paint introduced into the main supply line 5b is detected.

Another paint supply unit 7c comprises according to Fig. 6 the paint reservoir 8c from which the paint material is conveyed into the main supply line 5c with a paint feed pump 9c. Further shows Fig. 6 a release valve 17c which releases the paint flow toward the main supply pipe 5c, and a release valve 18c which releases the paint flow into a return pipe 19c into the paint reservoir 8c. Furthermore, a rinsing agent valve 20c, with which rinsing agent can be brought to the suction side of the paint conveying pump 9c, are provided, around the paint conveying pump 9c and the return line 19c to flush the paint reservoir 8c, and a purge valve 21c, with which the detergent can be pressed out of the paint delivery pump 9c and out of the purged lines. A release valve 22c completes the paint supply unit 7c and releases the flow of the rinsing agent or purge air either through the paint feed pump 9 or through the suction line into the paint reservoir 8c.

The main supply line 5 can according to Fig. 1 be any length and leads to one or more, arranged along the paint booth color changers 23, 24 and 25, of which each of at least one stub 26, 27 and 28 leads to the acceptance or injection points, where it is around the atomizers 2, 3 and 4, respectively.

The main supply line 5 is executed piggable and preferably a stub. It leads to at least one, but usually to a plurality of successively arranged pickup points or atomizers 2, 3 and 4. It can also be two or more such main supply lines (5a - x) are performed in parallel to different collection points / atomizers, for example, on opposite sides a paint booth.

Other paint supply lines 29, which may also be ring lines, may be guided by the color changers 23, 24 and 25, respectively.

Each main supply line 5 has a release valve 30 at its beginning or at its one, delivery pump end 6, then follows a first parking station 31 for a pig 32 and terminates preferably behind the last delivery point with a second parking station 33, in which the pig 32 can pass the operatively flowing past him fluid. Connected to the parking station 33 arranged at the second end 34 is a valve combination which comprises at least one valve 35 for release into a collecting line or into a collecting container 36 and a valve 37 for flushing agent and a valve 38 for a pushing medium, preferably compressed air.

To detect the incoming paint column, a sensor 39, preferably a pressure sensor, may be arranged at the parking station 33.

Basically similar components as the second parking station 33 are also associated with the first parking station 31 and include a valve 40 for release into a collecting line or into a collecting container 41, a valve 42 for detergent and a valve 43 for a sliding medium, preferably compressed air. A sensor 44 for detecting the incoming in the parking station 31 pig 32 is also provided.

The paint supply to the individual delivery points or atomizers for painting individual workpieces or small batches takes place in such a way that after the connection of the paint reservoir 8 to the paint delivery pump 9 and to the main supply line 5, the release valve 30 is opened first, so that the paint to the valve 35 disposed at its end. During the filling time of the main supply line 5, the valve 35 arranged behind the second parking station 33 is opened.

After opening the release valve 30, only the amount of paint in the main supply line 5 is introduced, which is required for the painting of the individual workpiece or the smallest series. In addition, there is a certain, inevitable surplus to compensate for loss of fill. The metering of the filling quantity takes place via the quantity measuring device 10 or via a controller which controls the release valve 30 and the valve 35 at the other end of the main supply line 5 as a function of the signals from the quantity measuring device 10 and by means of preprogrammed demand data.

Dananch are the color changer 23 to 25, from which / lead from the stubs 26 to 28 to the pickup or spray points / atomizers 2 to 4, operationally clear.

It is further assumed that the conveying direction of the workpiece to be painted in the direction of arrow 45, ie in the direction of flow of the paint in the main supply line. 5

Before each color changer 23, 24 and 25, a sensor 46, 47 and 48 is arranged, which detects the moving behind the filled paint column pig 32. The signal can be used to ensure that the color valve associated with the color changer closes before the pig 32 passes the respective color changer.

Depending on the amount of paint to be applied to the respective atomizers 2 to 4, one or the other branch line 26 to 28 may also already be filled in whole or in part together with the main supply line 5. The dosage of the amount of paint for each atomizer 2 to 4 is taken over by a metering unit 49 arranged in each case between the color changer 46 to 48 and the atomizer 2 to 4. This may be a remote-controlled paint pressure regulator, a gear metering pump or other actuator. It is further understood that metering units 49 are arranged in all branch lines and that the volume flow at the relevant points measuring and controlling control and / or measuring devices are provided, without this being shown in detail in the figures.

The paint introduced into the main supply line 5 is applied to the atomizer 2, 3 or 4 during the pigging operation and thereby completely or almost completely consumed. If the stubs 26-28 are relatively short, the remainder there will be discarded later.

Is one or more stub lines 50 as in the case of im Fig. 2 illustrated embodiment is relatively long, so the residual paint contained therein can be pressed back into the main supply line 5 after completion of the painting process. This is done with the help of another pig 51, for which the stub 50 parking stations 52 and 53 and the associated valves 54 and 55 for a sliding medium or for detergent.

According to the in Fig. 2 In the case illustrated, the paint column located in the stub 50 can be pushed back to the main supply line 5 by means of the pig 51 after completion of painting on the atomizer so that the paint can then be pressed into another stub, the atomizer still needs paint.

Also, it is in principle possible to fill one stub after the other and back again to empty, if the corresponding stub lines in addition to the main supply line 5 are each equipped with their own parking stations and each own pig such that the pig located in the stub line paint column back to the main supply line 5.

If the pig 51 at the in Fig. 2 illustrated embodiment during the Lackierbetriebes not parked in the atomizer side parking station 52, but in the color changer 24 parking station 53 and if this parking station 53 is connected via a valve not shown to at least one push medium, it is possible, even the contents of the stub 50th still to consume over the atomizer 3.

Due to the described method, the amount of paint introduced into the main supply line 5 must correspond only to the actual net painting requirement and exceed this only by an extremely small amount of paint that can not be avoided by circuit-related line losses. Irrespective of this, no residue to be disposed of remains as soon as the painting of the individual workpiece or of the small series on the last atomizer has been completed. The initially charged in the main supply line 5 amount of paint is completely consumed.

With the help of the two valve combinations in front of the scraper parking station 31 and behind the scraper parking station 33, the main supply line 5 can now be optionally purged in both directions.

According to the in Fig. 3 illustrated embodiment, the main supply line 5 for supplying a nebulizer 3 'is not directly guided by the color changer 24' or connected directly to one of its valves, but it is 3durch a spatially separated Farbwechlsereinheit 60 out. Via the valve 61 located there and a special line 62, the main supply line 5 is connected to one of the valves 63 of the color changer 24 '.

The valve 61 is also connected via a line to a valve 64 for a sliding medium and to a valve 65 for a detergent. Respective valves 66 and 67 for a pushing medium and for rinsing agents are connected to all the color changers 23 to 25 and 24 'and so on.

A sensor 68 is also assigned to the color changer unit 60, as is also the case for the other color changers.

The pig parking stations 31 and 33 or 52 and 53 serve respectively for parking and for collecting the pig 32 or the pig 51.

Claims (10)

1. Method for coating, in particular for painting individual objects or small series with a small quantity of paint by means of several sprayers (2, 3, 4) arranged one behind the other, using a main supply line (5), on one end/beginning (6) of which a paint supply unit (7) is arranged, characterized in that only the total paint quantity required and in addition a minimum residual quantity are fed into the main supply line (5), independently of the latter's length and actual capacity, and that the contents of the main supply line (5) are pressed by means of a scraper (32) charged by a pushing medium, towards the sprayers (2, 3, 4) still to be operated, and are delivered there completely or almost completely.
2. Method according to claim 1, at least one sprayer (3) being arranged on the free end of a stub line (50) whose other end is arranged on a color changer (24) through which the main supply line (5) passes, characterized in that the contents of the stub line (50), after termination of the coating, are emptied by means of a scraper (51) by pressing them in the direction of the color changer (25) and the main supply line (5).
3. Method according to claim 1, at least one sprayer (3) being arranged on the free end of a stub line (50) whose other end is arranged on a color changer (24) through which the main supply line (5) passes, characterized in that the contents of the stub line (50), before termination of the coating, are emptied by means of a scraper (51) by pressing them in the direction of the sprayer (3).
4. Method according to claim 1, characterized in that the dosing and/or control and/or measuring devices measure and control the volume flow rate at the relevant positions.
5. Method for coating, in particular for painting individual objects or small series with a small quantity of paint by means of several sprayers (2, 3, 4) arranged one behind the other, using a main supply line (5), on one end (6) of which a paint supply unit (7) is arranged, characterized in that on each of the two ends of the main supply line (5), one parking station (31, 33) for a scraper is provided and lines leading into the parking station (31, 33) are provided, in each of which a valve for a pushing medium, preferably compressed air, a valve for a flushing agent, and a valve for release into a collecting line or into a container are arranged.
6. Method according to claim 5, characterized in that a sensor (44) for detecting an arriving scraper (32) is arranged on the parking station (31).
7. Method according to claim 5, characterized in that the paint supply unit (7) is arranged in a central position.
8. Method according to claim 5, characterized in that the main supply line (5) passes through several color changers (23, 24, 25) and in that in each case a stub line (26, 27, 28) leads from the color changer (23, 24, 25) to a sprayer (2, 3, 4).
9. Method according to claim 5, characterized in that the paint column contained in the stub line (50) can be moved by means of a scraper (51) in the direction of the sprayer (3) or in the direction of the main supply line (5).
10. Method according to claim 5, characterized in that the main supply line (5) passes through one or several color changers, operating automatically, from which the paint is in each case fed to a second color changer, which might also be fed by other paint-feeding sources and which supplies one or several associated sprayers.

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