EP2566628B2 - Atomizer with a lattice mixer - Google Patents

Description

The invention relates to an atomizer, in particular a rotary atomizer, for applying a coating composition consisting of several components.

In modern painting systems for painting motor vehicle body components, rotary atomizers are usually used as the application device, some of which can also apply multi-component paints which consist of several coating agent components, such as, for example, a base paint and a hardener. It is important here that the various components of the multi-component lacquer are mixed as well as possible in the atomizer. For this purpose, the conventional rotary atomizers have static spiral mixers, which are also referred to as Kenics ^® mixers. These spiral mixers have numerous spiral-shaped mixing elements that direct the coating agent flow radially outwards and then lead it back to the center. Usually, two separate spiral mixers are used, the first spiral mixer being arranged in the color tube of the rotary atomizer, while the second spiral mixer is located outside the color tube in the connection block of the rotary atomizer.

A disadvantage of this conventional design is the fact that a relatively long overall length of the mixer is required, so that large losses of paint or detergent occur during a color change or during rinsing processes.

Further disclosed DE 82 31 663 U1 a paint guide tube in an atomizer, a static mixer being arranged in the paint guide tube. However, this known mixer also requires a relatively large overall length.

Reference should also be made to the state of the art DE 30 40 136 A1 and US 4,614,440 .

Further disclosed US 2004/0114461 A1 a so-called lattice mixer, which is a static mixer that is used for mixing highly viscous liquids, for example in injection molding machines. So far, however, such lattice mixers have not been used in atomizers, especially since it was assumed that such lattice mixers are only suitable for mixing highly viscous liquids.

Reference should also be made to the state of the art US 2006/0192033 A1 and WO 2008/136827 A1 .

Finally revealed FR 2 890 876 A1 an atomizer according to the preamble of the main claim. A disadvantage of this known atomizer with a lattice mixer, however, is the unsatisfactory mixing effect of the lattice mixer.

The object of the invention is therefore to create a correspondingly improved atomizer with a structurally integrated mixer.

This object is achieved by an atomizer according to the invention according to the main claim.

The invention encompasses the general technical teaching of using another type of mixer, namely a so-called lattice mixer, which has numerous mixing elements which are arranged in a lattice-like arrangement. Grid mixers of this type are made, for example US 2004/0114461 A1 is known, so that the content of this document of the present description with regard to the structure and operation of a grid mixer is fully attributable.

A common feature of the new mixer according to the invention with the conventional spiral mixer is that it is a static mixer in both cases. This means that the mixer itself has no moving parts, since the mixing is brought about by the flow movement of the coating agent components to be mixed with one another.

The grid mixer, on the other hand, differs from the conventional spiral mixer in the arrangement and design of the individual mixing elements. For example, the conventionally used spiral mixer has spiral-shaped mixing elements which divert the flow of coating agent in a spiral, the mixing elements adjacent in the flow direction each having opposite deflection directions, as a result of which the mixing is effected. In contrast, the lattice mixer used according to the invention preferably has elongated, straight, sharp-edged and rod-shaped mixing elements which are made of plastic and each have an essentially rectangular cross section. These mixing elements therefore each cause turbulence, which leads to effective mixing of the coating agent components to be mixed with one another.

The individual mixing elements are arranged in a grid-like manner. In the preferred embodiment of the lattice mixer according to the invention, a plurality of rod-shaped mixing elements are arranged together in one plane and thus form a lattice, a plurality of such lattices consisting of a plurality of mixing elements being interleaved.

It should also be mentioned that the individual mixing elements preferably have a certain angle of attack relative to the flow direction. This means that the individual mixing elements are not aligned parallel to the direction of flow, since this would only lead to a low mixing effect. The angle of attack of the mixing elements with respect to the direction of flow is preferably greater than 20 °, 30 ° or 40 ° and / or less than 70 °, 60 ° or 50 °. In the preferred embodiment, the angle of attack is essentially the same for all mixing elements. However, there is alternatively also the possibility that the mixing elements have different angles of attack.

Here, the mixer has several sections, which are arranged one behind the other in the direction of flow are and are flowed through in succession. The different sections can differ, for example, in the orientation of the mixing elements. For example, the angle of attack of the mixing elements can fluctuate relative to the flow direction between the sections. In the preferred embodiment of the invention, the mixer has a total of more than 5, 6, 7, 8, 9, 10 or even more than 11 different sections. There is the possibility here that the immediately adjacent sections of the mixer are each designed differently, for example with regard to the angle of attack or the orientation and design of the mixing elements, the section after the next but one again having the same structure.

It should also be mentioned that the mixer is preferably elongated in the direction of flow and has an essentially cylindrical cross section, the mixer preferably being arranged completely inside the atomizer.

It is also important that the mixer preferably has a length in the flow direction that is less than 10 cm, 8 cm or even 6 cm. This advantageously enables the mixer to be arranged completely in the paint tube of the atomizer. The overall length of the mixer is therefore preferably less than the overall length of the paint tube of the atomizer.

In the preferred exemplary embodiment, the atomizer according to the invention, like the conventional atomizers, has a controllable main needle valve which either releases or blocks the flow of coating agent. When the main needle valve is closed, the atomizer does not apply any coating agent, so that the valve position of the main needle valve determines whether the atomizer applies the coating agent or not. The mixer is arranged upstream of the main needle valve so that the ready mixed coating agent is present on the main needle valve. It is advantageous here if the mixer is moved as far upstream as possible to the main needle valve in order to minimize the distance between the downstream end of the mixer and the main needle valve. This is advantageous because it reduces the amount of paint or solvent used when changing colors or rinsing. The line length between the downstream end of the mixer and the main needle valve is therefore preferably shorter than 10 cm, 6 cm, 5 cm, 4 cm, 3 cm, 2 cm or even shorter than 1 cm.

It has already been mentioned above that the atomizer according to the invention - like the conventional atomizers - has a hollow paint tube in order to supply the coating agent to be applied. The advantages of the grating mixer according to the invention offer the possibility that the mixer is arranged completely in the paint tube, so that under certain circumstances an additional mixer in the connection block of the atomizer can be dispensed with, which was necessary in the conventional atomizer described at the beginning. It should be mentioned here that the paint tube can also form the casing of the usually cylindrical mixer, so that an additional mixing pipe for the casing of the mixer can be dispensed with. It should also be mentioned that the diameter of the mixer essentially corresponds to the diameter of the paint tube in one exemplary embodiment, so that the mixer completely fills the cross section of the paint tube. However, there is also the possibility within the scope of the invention that several mixers are arranged side by side in the paint tube of the atomizer, which will be described in detail below.

This is useful, for example, if the atomizer is suitable for the application of different paint systems, each of the two paint systems having several components, in particular a base paint and a hardener. A mixer is assigned to each of the two coating systems in order to mix the components of the coating system with one another.

As already mentioned briefly above, there is the possibility here that the mixers for the different paint systems are arranged together in the paint tube, the mixers for the different paint systems preferably being located next to one another with respect to the direction of flow. Each mixer for the different paint systems then fills only part of the cross-section of the paint tube. In addition, the various mixers are then preferably encased by a mixing tube in order to separate the various mixers from one another.

It should also be mentioned that the mixers for the different color systems can have different mixing properties that are adapted to the properties of the respective color system in order to achieve the best possible mixing result.

Alternatively, there is also the possibility that the mixers for the different paint systems are not arranged together in the paint tube. For example, the mixer for the one paint system can be arranged in the paint tube, while the mixer for the other paint system is located outside the paint tube, for example in a valve or connection block of the atomizer upstream of the paint tube.

In general, it should be mentioned that the atomizer according to the invention has several mixers, which can also be very useful in general for optimizing the mixing result.

(painted)

• Figur 1: eine schematisierte Querschnittszeichnung eines nicht erfindungsgemäßen Rotationszerstäubers mit einem integrierten Gittermischer,
• Figur 2: eine Perspektivansicht des Gittermischers aus dem Rotationszerstäuber gemäß Figur 1,
• Figur 3: ein vereinfachtes Diagramm zur Verdeutlichung des Aufbaus eines Rotationszerstäubers zur Applikation von zwei verschiedenen Lacksystemen, wobei in das Farbrohr des Rotationszerstäubers zwei Mischer integriert sind,
• Figur 4: eine erfindungsgemäße Abwandlung von Figur 3, wobei der eine Mischer in dem Farbrohr angeordnet ist, während sich der andere Mischer in dem Ventilblock befindet.

Other advantageous developments of the invention are characterized in the subclaims or are explained in more detail below together with the description of the preferred exemplary embodiments of the invention with reference to the figures. Show it:

• Figure 1 : a schematic cross-sectional drawing of a rotary atomizer not according to the invention with an integrated lattice mixer,
• Figure 2 : a perspective view of the lattice mixer from the rotary atomizer according to Figure 1 ,
• Figure 3 : a simplified diagram to illustrate the structure of a rotary atomizer for the application of two different coating systems, two mixers being integrated in the paint tube of the rotary atomizer,
• Figure 4 : a modification of Figure 3 , wherein one mixer is arranged in the paint tube, while the other mixer is in the valve block.

Figure 1 shows a rotary atomizer 1, which can be used, for example, for painting motor vehicle body components, the rotary atomizer 1 being constructed largely conventionally, so that a detailed description of the structure and operation of the rotary atomizer 1 can be dispensed with. For the description of the invention it is only important that the rotary atomizer 1 has a paint tube 2 which is fastened to a connection block 3, the paint tube 2 being aligned coaxially with the axis of rotation of a bell cup shaft 4 in order to supply the coating agent to be applied.

A grating mixer 5 is arranged in the paint tube 2 in order to mix the various components (e.g. master varnish and hardener) of the coating composition with one another.

The lattice mixer 5 has numerous elongated, rod-shaped, sharp-edged mixing elements 6 which are arranged in a lattice-like manner, with the mixing elements 6 generating turbulence in the paint tube 2, which leads to thorough mixing.

The grid mixer consists of a total of twelve sections 7, 8, which are arranged one behind the other in the direction of flow and flow through one after the other. The different sections 7, 8 of the lattice mixer 5 differ in the orientation of the individual mixing elements 6, as shown in the perspective view in FIG Figure 2 can be seen.

Figure 3 shows a schematic diagram to illustrate the structure of a rotary atomizer 9 according to the invention, which is suitable for the application of two different paint systems, the first paint system consisting of a first base paint SL1 and a first hardener H1, while the second paint system consists of a second base paint SL2 and a second hardener H2.

To apply the various coating systems, the rotary atomizer has two main needle valves 10, 11 and one grating mixer 12, 13 each, the two grating mixers 12, 13 being arranged together next to one another in a paint tube 14 of the rotary atomizer 9. The lattice mixer 12 mixes the first base paint SL1 with the first hardener H1, while the other lattice mixer 13 mixes the second base paint SL2 with the second hardener H2.

The two grid mixers 12, 13 correspond in structure and function to the grid mixer 5 according to FIGS Figures 1 and 2nd .

In addition, the rotary atomizer 9 also has a connection block 15 with integrated valves in this exemplary embodiment.

It can also be seen from the drawing that the two grid mixers 12, 13 are arranged at a very short distance 1 <5 cm upstream of the associated main needle valves 10, 11. This is advantageous because the line section to be rinsed between the lattice mixers 12, 13 and the associated main needle valves 10, 11 thus has a small volume, so that the detergent losses and the paint losses are correspondingly small.

Figure 4 shows a modification of the embodiment according to Figure 3 , so that to avoid repetition reference is made to the above description, the same reference numerals being used for corresponding details.

A special feature of this exemplary embodiment is the arrangement of the two grid mixers 12, 13. Thus, the grid mixer 12 in this exemplary embodiment is also located within the paint tube 14, whereas the other grid mixer 13 is integrated in the connection block 15.

The invention is not restricted to the preferred exemplary embodiments described above. Rather, a large number of variants and modifications are possible which also make use of the inventive idea and therefore fall within the scope of protection. It should also be mentioned that the invention also claims protection for the subject matter of the subclaims regardless of the features of the preceding claims.

Reference symbol list:

1

Rotary atomizer

2nd

Paint tube

3rd

Terminal block

4th

Bell plate shaft

5

Lattice mixer

6

Mixing elements

7

Section of the grid mixer

8th

Section of the grid mixer

9

Rotary atomizer

10th

Main needle valve

11

Main needle valve

12

Lattice mixer

13

Lattice mixer

14

Paint tube

15

Terminal block

H1

First hardener

H2

Second hardener

1

Line length between lattice mixer and main needle valve

SL1

First master paint

SL2

Second base coat

Claims (9)

1. An atomizer (1; 9), particularly a rotary atomizer, for the application of a coating agent consisting of several components, with

   a) a static mixer (5; 12, 13) which mixes the various components (SL1, H1, SL2, H2) of the coating agent with one another, wherein the mixer (5; 12, 13) has a plurality of fixed mixing elements (6) and is constructionally integrated into the atomizer (1; 9),

   b) wherein the mixer (5; 12, 13) is a lattice mixer, in which the mixing elements (6) are arranged intertwined in a lattice-like manner,

   c) wherein the mixer (5; 12, 13) comprises a plurality of sections (7, 8) which are arranged one behind the other in the direction of flow and through which the flow successively passes,
   characterized in that

   d) the mixing elements (6) in the adjacent sections (7, 8) of the mixer (5; 12, 13) in the direction of flow are aligned differently, so that the different section (7, 8) differ in the alignment of the mixing elements (6),

   e) the atomizer (1; 9) is suitable for application of at least two different paint systems, wherein each of the two paint systems has a plurality of components, particularly a base paint (SL1, SL2) and a hardener (H1, H2), and

   f) the atomizer (1; 9) for each of the two paint systems has a mixer (5; 12, 13) in each case, wherein the mixers (5; 12, 13) are constructionally integrated into the atomizer (1; 9).
2. The atomizer (1; 9) according to Claim 1, characterized in that

   a) the individual mixing elements (6) have an essentially rectangular cross section in each case, and/or

   b) the individual mixing elements (6) are elongated in each case, and/or

   c) the individual mixing elements (6) are straight in each case, and/or

   d) the individual mixing elements (6) are sharp-edged in each case, and/or

   e) the individual mixing elements (6) are rod-shaped in each case, and/or

   f) the individual mixing elements (6) consist of plastic.
3. The atomizer (1; 9) according to any one of the preceding claims, characterized in that

   a) the individual mixing elements (6) have a certain pitch angle relative to the direction of flow, and/or

   b) the pitch angle of the mixing elements (6) is greater than 20°, 30° or 40° and/or smaller than 70°, 60° or 50°, and/or

   c) the pitch angle for all mixing elements (6) is essentially the same.
4. The atomizer (1; 9) according to any one of the preceding claims, characterized in that

   a) the number of sections of the mixer (5; 12, 13) is larger than 5, 6, 7, 8, 9, 10 or 11, and/or

   b) the mixer (5; 12, 13) is elongated in the direction of flow, and/or

   c) the mixer (5; 12, 13) is essentially cylindrical, and/or

   d) the mixer (5; 12, 13) has an overall length of less than 10cm, 8cm or 6cm, and/or

   e) the mixer (5; 12, 13) is arranged completely within the atomizer (1; 9).
5. The atomizer (1; 9) according to any one of the preceding claims, characterized in that

   a) the atomizer (1; 9) has a controllable main needle valve (10, 11) which determines whether the atomizer (1; 9) applies the coating agent or not as a function of the valve position thereof, and

   b) the mixer (5; 12, 13) is arranged upstream of the main needle valve (10, 11), and

   c) a line length (1) lies between the end of the mixer (5; 12, 13) positioned downstream and the main needle valve (10, 11), which is shorter than 10cm, 6cm or 5cm.
6. The atomizer (1; 9) according to any one of the preceding claims, characterized in that

   a) the atomizer (1; 9) has a hollow paint tube (14) in order to supply the coating agent, and

   b) the mixer (5; 12, 13) is arranged completely in the paint tube (14), and/or

   c) the mixing elements (6) are arranged without an additional mixing tube in the paint tube (14), and/or

   d) the diameter of the mixer (5; 12, 13) essentially corresponds to the diameter of the paint tube (14), so that the mixer (5; 12, 13) fills the cross section of the paint tube (14) completely.
7. The atomizer (1; 9) according to Claim 6, characterized in that

   a) the mixers (5; 12, 13) for the various paint systems are arranged together in the paint tube (14), and/or

   b) the mixers (5; 12, 13) for the various paint systems are arranged adjacently with respect to the direction of flow, and/or

   c) the mixers (5; 12, 13) for the various paint systems in each case only fill part of the cross section of the paint tube (14), and/or

   d) the mixers (5; 12, 13) for the various paint systems in each case have a mixing tube in which the mixing elements (6) are arranged, wherein the mixing tubes separate the mixers (5; 12, 13) from one another, and/or

   e) the mixers (5; 12, 13) for the various paint systems have different mixing properties which are adapted to the properties of the respective paint system.
8. The atomizer (1; 9) according to Claim 6, characterized in that the mixer (5; 12, 13) for one paint system is arranged in the paint tube (14), whilst the mixer (5; 12, 13) for the other paint system is located outside of the paint tube (14), for example in a valve block of the atomizer (1; 9) upstream of the paint tube (14).
9. The atomizer (1; 9) according to one of the preceding claims, characterized in that a plurality of mixers (5; 12, 13) are arranged in the atomizer (1; 9).

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