DE29719535U1 - Multi-color painting device - Google Patents

Description

Multi-colour painting equipment

The invention relates to a multi-colour painting device according to the preamble of claim 1.

In automatic painting systems, the paints/varnishes to be processed are fed from a paint supply system to a spray head, which is particularly designed as a rotary atomizer.

In known painting systems, the paints to be processed using this spray head are pumped under pressure via a feed line from a pump-type conveying and dosing device. The pump is connected to a paint changer on the input side, to which the paints/colors to be processed can be optionally fed via individual valves. The paint changer also includes a flushing combination, by means of which the collecting line, the pump and the feed line to the spray head are cleaned of paint residues using solvents and/or air after a paint has been processed.

In painting systems constructed in this way, the supply line between the pump and the spray head is often several meters long. Consequently, when a color is changed, the entire line system, consisting of the collecting line from the color changer to the pump and the supply line from the pump to the spray device, must be cleared of paint residues by the flushing combination arranged in the paint changer. If a large number of paint changes are made during production, the quantities of paint that are released in the supply line between the pump and the spray head through the flushing process add up and are collected in a container assigned to the spray head.

For this purpose, the spray head has a switchable valve, by means of which the paint in the supply line between the pump and the spray head

can be pumped out. The paint-solvent mixture fed into the receiving container cannot be reused.

With a large number of paint changes during production, the paint quantities that can no longer be processed add up to

several liters, which is costly. Another disadvantage is that, due to the long supply system mentioned above, correspondingly large quantities of solvent must be used in order to be able to dissolve even the last traces of paint. Another disadvantage is the time required for a paint change.

of a painting system constructed in this way, which is also caused by the large amount of paint that has to be released from the supply line and the corresponding amounts of solvent.

The object of the present invention is therefore to further develop a multi-color painting device according to the preamble of claim 1 in such a way that a paint change is possible with noticeably reduced expenditure of paint that can no longer be used and also noticeably reduced solvent consumption and the period of time required for a paint change can be shortened.

This object is achieved by the characterizing features of claim 1. Further developments of the invention emerge from the subclaims.

According to the invention, the spray head, which is designed in particular as a rotary atomizer, has a supply line for each paint to be processed, which is used exclusively for the paint to be processed. In the spray head, in the area of the outlet, pressure relief valves designed for a specific pressure for the respective paint are arranged, so that the pressure

* · · »y _tt * j

The paint supplied with the appropriate pressure can be fed to the atomization system of the spray head.

In a painting system designed for a number N of paints, N supply lines and correspondingly N pressure relief valves are arranged in the spray head. On the input side, the N supply lines are assigned pressure relief valves in the form of 3/2 valves, through which the paint to be processed can be fed from a corresponding supply via the respective line under pressure to the spray head.

&iacgr;&ogr;, whereby if this varnish is not required, the 3/2 valve is so

is switched so that the paint initially under pressure in the respective supply line can exit the supply system again after switching to another color. It is possible to return the paint that exits the supply system after switching the 3/2 valve to a corresponding supply for this paint. This paint return can take place directly into the container that provides the paint or, alternatively, it is possible to provide a separate receiving container, whereby in the latter case the paint is returned at certain times or when required.

Through the use according to the invention of pressure relief valves arranged in the spray head in conjunction with the supply lines provided in the corresponding number of paints/colors to be processed, it is possible to process a significantly larger number of paints/colors using a spray head or to supply them via individual lines than is the case with conventional multi-color painting devices. The pressure relief valves provided in the spray head according to the invention only require a fraction of the installation space that conventional switching valves take up. In particular, pressure relief valves can be used which have a diameter in the order of magnitude of the respective

supply line and are located at the end of the supply lines leading into the spray head. Instead of pressure relief valves, nozzles can also be used through which the paint can only escape when there is pressure. In conjunction with the 3/2 valves, the pressure relief valves/nozzles in the spray head can be closed in a targeted manner, preventing any dripping.

By applying the invention, it is possible to further develop the spray head designed as a rotary atomizer with a number of

&iacgr;&ogr; Ring gaps for the paint outlet, so that a too

The paint being processed can be fed to a respective ring gap. The individual ring gaps for the paint outlet are arranged concentrically around the rotation axis of the atomizer curl in the middle of its front. It can preferably be provided that a ring gap is assigned to each type of paint/color. This makes it possible to use the outer ring gaps for dark or difficult to rinse colors and the inner ring gaps for light or easily rinsed paints/colors. This reduces the amount of solvent required to clean the rotary atomizer and the rinsing times required for a cleaning process.

According to a further development of the invention, it is provided that the paints/colors to be processed are fed to the individual 3/2 valves used for pressure equalization via a common conveying and dosing device (pump). In this case, a color changer constructed in a conventional manner is arranged upstream of the conveying and dosing device (pump), consisting of a common collecting line with a flushing combination, whereby the individual paints/colors can be fed to the collecting line passing through the color changer via switchable valves. The paint required in each case is fed from the conveying and dosing device of this color changer via a further common collecting line to the 3/2 valve assigned to this paint.

valve in order to reach the spray head from there via the respective supply line. The 3/2 valves are assigned a corresponding number of lines, by means of which the paint that escapes during pressure equalization can be returned to the corresponding receiving containers or the paint storage containers. Thus, with this development of the invention, it is also possible to collect the paint/paint quantities that escape during a color change with the associated pressure equalization separately and thus return them to the processing (the respective storage container).

&iacgr;&ogr; Paint change is carried out by the flushing combination of the conveyor and

The dosing device of the paint changer upstream of the dosing device allows the collection line of this paint changer and the collection line downstream of the conveying and dosing device (pump) to be flushed. For this purpose, an outlet and a receiving container that can be opened via a switchable valve are arranged at the outlet of this collection line downstream of the dosing and pressure unit.

The multi-color painting device according to the invention can be used to process not only conventional paints/colors but also powders or multi-component paints. Accordingly, the term "paint" is to be interpreted generally in the present application.

When processing multi-component paints, the individual components are preferably mixed in the spray head when the components to be mixed are introduced into a chamber of the spray head using the pressure relief valves. It is also possible to mix the components when they leave the spray head/rotary atomizer if, as in the preferred embodiment of the invention, the spray head/rotary atomizer has several chambers that can be acted upon using the pressure relief valves.

For processing multi-component paints, the embodiment of the invention is preferably used in which the individual paints /

Colors/powders/components etc. are fed to the spray head via a conveyor and metering device. In this way, any number of colors can be mixed and processed without the corresponding components having to be mixed in separate containers beforehand. This also results in considerable savings, since otherwise the color mixed in a separate container would leave residues even with optimal metering. These residues would then have to be removed again using a corresponding amount of solvent, which is not the case with the present invention.

Furthermore, embodiments of the invention are explained using the drawing. It shows:

Fig. 1 shows a painting device in which each

A conveying and dosing device is assigned to the paint to be processed,

Fig. 2 a painting device with a conveyor and

Dosing device and upstream paint changer, and

Fig. 3 shows a preferred embodiment of the invention

Rotary atomizer.

According to the embodiment of the invention according to Figure 1, a spray head 1 is designed to process a total of N colors. For this purpose, the spray head 1 is connected to the respective paint supply containers 5.1 to 5.N via a total of N supply lines 2.1 to 2.N via 3/2 valves 4.1 to 4.N used for pressure equalization.

Spray head 1 has pressure relief valves 3.1 to 3.N attached to the end of each supply line 2.1 to 2.N. The inlet of each 3/2 valve 4.1 to 4.N used for pressure equalization and switching on the respective paint to be processed is connected to the associated supply container 5.1 to 5.N for paint via a conveying and dosing device 6.1 to 6.N in the form of a pump arranged in a feed 8.1 to 8.N. The outlet of the 3/2 valve 4.1 to 4.N used for pressure equalization is connected via a return 7.1 to 7.N to the supply 5.1 to 5.N of the corresponding paint.

If paint from the storage container 5.1 is first processed, the 3/2 valve is switched to allow passage between the feed 8.1 and the feed line 2.1. The pressure from the conveying and dosing device 6.1 opens the pressure relief valve 3.1 so that the paint from the storage container 5.1 can reach the spray head 1 and be processed accordingly. The other conveying and dosing devices - 8.1N are switched off, and the 3/2 valves - 4.N used for pressure equalization are also switched in such a way that paint/paint in the feed lines - 2.N can flow back into the storage containers - 5.N via the respective return lines - 7.N. To switch to another paint - for example the paint in the storage container 5.N - the conveying and dosing device 6.1 is now switched off and the 3/2 valve 4.1 used for pressure equalization is switched so that the paint under pressure in the supply line 2.1 can flow back into the storage container 5.1.

After cleaning the spray head 1 with rinsing devices (not shown), the 3/2 valve 4.N is then switched to pass between the feed 8.N and the feed line 2.N and at the same time the conveying and dosing device 6.N is switched to convey paint in the direction of the spray head 1. The pressure building up in the feed line 2.N opens the pressure relief valve 3.N in the spray head 1, so that the paint can exit there with the required pressure. Since only the paint to be processed is present in the feed lines 2.1 to 2.N, there is no need for a time-consuming and solvent-intensive process.

&iacgr;&ogr; consuming flushing process of an otherwise between spray head 1 and

the pipe system connecting the storage containers 5.1 to 5.N with the spray head 1.

According to the embodiment of the invention according to Figure 2, the feed inlets of the 3/2 valves 4.1 to 4.N used for pressure equalization are connected to a common collecting line 9, which is connected on the input side to a conveying and dosing device common to all paints. This conveying and dosing device 6 common to all paints is connected to the output of a paint changer constructed in a known manner with a collecting line 10, whereby the paints to be processed can be connected via valves 11.1 to 11.N from storage containers 5.1 to 5.N. The return lines 7.1 to 7.N of the 3/2 valves 4.1 to 4.N used for pressure equalization are also connected directly to the storage containers 5.1 to 5.N for the paints to be processed using the spray head 1 in this embodiment of the invention. This means that the unprocessed paints can be returned to the storage containers 5.1 to 5.N through the respective 3/2 valve 4.1 to 4.N, which serves to equalize the pressure.

In the previously described embodiment of the invention according to Figure 2, the paint changer with the collecting line 10 and the valves 11.1 to 11.N connected downstream of the storage containers 5.1 to 5.N is assigned a flushing combination 12, by means of which the collecting line 10, the conveying and metering device (pump) 6 connected downstream of the collecting line 10 and the subsequent collecting line 9 are to be cleaned of the paint that has flowed through in a previous work step. For this purpose, the flushing combination 12 has switchable

&iacgr;&ogr; connections for solvent and/or air, so that the manifold

10, the conveying and dosing device 6 and the second collecting line 9 can be supplied with solvent or air to remove paint. The end of the collecting line 9 has a switchable valve 13, so that during a rinsing process the dissolved paint or varnish residues can be collected in a collecting container 14 and then disposed of.

In this embodiment, the spray head 1 is also connected to a number of supply lines 2.1 to 2.N for the respective paint to be processed and has pressure relief valves 3.1 to 3.N in addition to the 3/2 valves 4.1 to 4.N for pressure equalization. The collecting line 9, 10 through which the various paints flow as well as the conveying and dosing device 6 are to be designed as short as possible so that the amount of solvent to be used during a rinsing process (paint/color change) and the time required for a rinsing process can be significantly reduced.

A bypass valve 19 is assigned to the conveying and dosing device 6; by means of which both solvent and paint can be conveyed past the pump in both directions. In order to keep the residues arising when changing paint as low as possible, a bypass valve 19 is provided at the end of the collecting line 9 in front of the valve 13 for flushing the

A further solvent valve 20 is arranged between the collecting lines 9, 10 via the flushing combination 12. After a painting process, solvent is introduced via this solvent valve 20 for a predetermined period of time (switching time of the valve) at such a pressure into the collecting line 9 and via the bypass valve 19 into the collecting line 10 so that the paint in the line system can be fed back into the corresponding supply lines. For this purpose, the pressure of the introduced solvent is higher by a certain amount than the pressure at which the paint is in the line system.

&iacgr;&ogr; The pipes are then flushed using the flushing combination

12 and the discharge of the remaining paint/solvent mixture into the collecting container 14. The previously described return of the paint significantly reduces the paint loss that occurs when changing the paint.

Figure 3 shows a spray head 1 in the form of a rotary atomizer that is preferably used in the invention. This consists of an atomizer bell 16 that is placed on a stator 15 and is mounted so that it can rotate about an axis of rotation D by a drive means (compressed air turbine) that is not shown. At the open end of the atomizer bell 16, outlet gaps 18.1 to 18.N that run concentrically about the axis of rotation D are arranged, from which the paint/varnish to be processed can emerge from chambers 17.1 to 17.N located in the atomizer bell 16 and be distributed via the atomizer bell 16.

The chambers 17.1 to 17.N are connected to the pressure relief valves 3.1 to 3.N arranged at the ends of the supply lines 2.1 to 2.N, whereby these (contrary to the basic representation according to Figure 3) are preferably arranged in the stator 15 at the bottom of the respective chamber 17.1 to 17.N. In this way, each chamber 17.1 to 17.N can be supplied with the paint conveyed under pressure in the supply line 2.1 to 2.N.

"i":L. I i

The supply lines for air/solvent used for rinsing/cleaning the rotary atomizer shown in Figure 3 are not shown. Preferably, an outlet nozzle for solvent is attached to the open end of the atomizer bell 16 in the common center of the outlet gaps 18.1 to 18.N (rotation axis D).

*,,* * ··· ··· ·· · List of reference symbols

1 spray head

2.1 - 2.N supply line (paint)

3.1-3.N Pressure relief valve

4.1 - 4.N 3/2 valve (pressure equalization)

5.1 - 5.N Storage container (paint)

6 Conveying and dosing device (pump)

6.1 - 6.N Conveying and dosing device (per paint)

7.1 - 7.N return (3/2 valve - reservoir 5.1 to 5.N)

8.1 - 8.N Supply

9 Collecting line

10 Collecting line

11.1 -11. N valve (collecting line 10 - reservoir 5.1 to 5.N)

12 Sink combination

13 Valve

14 collection containers

15 Stator

16 Atomizer bell 17.1 - 17.N chamber

18.1 -18.N Exit slit (annular)

19 Bypass valve

20 Solvent valve D Rotary axis

Claims (1)

Protection claims 1. Multi-colour painting device with a paint consumer designed as a spray head, whereby different paints can be optionally supplied to the consumer via a line system, at least one conveying and dosing device and valves from storage containers providing the paints,
characterized, &iacgr;&ogr; that the spray head (1) for each paint to be processed has an exclusively a supply line (2.1 to 2.N) conveying this paint is assigned, at the ends of which facing the spray head (1) pressure relief valves (3.1 to 3.N) are arranged, and that the supply lines (2.1 to 2.N) are connected to first outputs of 3/2 valves (4.1 to 4.N), whereby an input of these 3/2 valves (4.1 to 4.N) is connected to a storage container (5.1 to 5.N) for paint and another output of the 3/2 valves (4.1 to 4.N) is connected to a return line (7.1 to 7.N) for paint that is not required. 2. Multi-colour painting device according to claim 1, characterized in that that the pressure relief valves (3.1 to 3.N) are designed as spring-loaded ball valves inserted at the ends of the supply lines (2.1 to 2.N) facing the spray head (1). 3. Multi-colour painting device according to claim 1, characterised in that the pressure relief valves (3.1 to 3.N) are designed as nozzles inserted at the ends of the supply lines (2.1 to 2.N) facing the spray head (1). 4. Multi-colour painting device according to claim 1, 2 or 3, characterised in that that the storage containers (5.1 to 5.N) for the paint to be processed are each connected to the inlets of the 3/2 valves (4.1 to 4.N) via a conveying and dosing device (6.1 to 6.N) and the feeds (8.1 to 8.N) connected downstream of these. &iacgr;&ogr; 5. Multi-colour painting device according to claim 1, 2 or 3, characterized, that the 3/2 valves (4.1 to 4.N) assigned to the supply lines (2.1 to 2.N) are connected with the inputs to a common collecting line (9), to which the paint to be processed can be fed by a conveying and dosing device (6) from the respective storage container (5.1 to 5.N) via switchable valves (11.1 to 11.N). 6. Multi-colour painting device according to claim 5, characterized in that that a color changer is arranged upstream of the common conveying and dosing device (6) and has the storage containers (5.1 to 5.N), valves (11.1 to 11.N) and a collecting line (10) that receives the paint to be processed, which has a flushing combination (12) for cleaning the collecting line (10) and a collecting line (9) downstream of the conveying and dosing device (6), and a valve (13) is assigned to the collecting line (9) for removing paint and solvent residues from the end of the collecting line (9). IS I. 7. Multi-colour painting device according to one of the preceding claims, characterised in that the pressure equalizing outlets of the 3/2 valves (4.1 to 4.N) for the return of paint are directly connected to the receiving containers (5.1 to 5.N) of the respective paints. 8. Multi-colour painting device according to claim 6 or 7, characterized in that that a bypass valve (19) is assigned to the conveying and dosing device (6) and a solvent valve (20) is assigned to the end of the collecting line (9), whereby solvent under pressure can be introduced into the collecting lines (9, 10) via the solvent valve (20) for a predetermined period of time during a paint change, whereby the pressure is higher than that of the paint present in the collecting lines (9, 10). 9. Multi-colour painting device according to one of the preceding claims, characterised in that the spray head (1) is designed as a rotary atomizer with an atomizer bell (16) rotatably mounted on a starter (15), and that in the atomizer bell (16) there are chambers (17.1 to 17.N) which can be filled with paint through the supply lines (2.1 to 2.N) via the pressure relief valves (3.1 to 3.N), which form a number of outlet gaps (18.1 to 18.N) running concentrically to the axis of rotation (D) at the open end of the atomizer bell (16). lO.Multi-colour painting device according to claim 9, characterized in that the pressure relief valves (3.1 to 3.N) are arranged at the bottom of the respective chamber (17.1 to 17.N).