WO2018030944A1

WO2018030944A1 - Device and method for applying paint on objects

Info

Publication number: WO2018030944A1
Application number: PCT/SE2017/050802
Authority: WO
Inventors: Martin Strand; Pär ANTONSSON BARKSTEDT; Joakim Petersson
Original assignee: Ikea Supply Ag
Priority date: 2016-08-09
Filing date: 2017-08-07
Publication date: 2018-02-15
Also published as: EP3496868A1; EP3496868A4

Abstract

The invention provides a device for applying paint on objects comprising a support (1 ) for supporting an object (2); and two or more spray heads (6) for providing a curtain of paint (7); wherein the support (1 ) and/or the two or more spray heads (6) are movable such that the object (2) can be moved at least partially through the curtain of paint (7); and wherein each of the spray heads (6) comprises a longitudinal slot (21 ) through which the paint exits the spray head (6) when forming the curtain of paint (7). The invention further provides a method for applying paint on an object.

Description

DEVICE AND METHOD FOR APPLYING PAINT ON OBJECTS

Field of the invention

The invention relates to a device for applying paint on objects, particularly on furniture or furniture parts. Background of the invention

Different application techniques are known for painting objects such as furniture or furniture parts. The two major techniques are roller-coating techniques and spray applications. In roller- coating applications, a roller is used for applying the paint on, for instance, a wooden board, whereas for spray applications, the paint is pressurized and sprayed onto the board via movable nozzles that move over the board to cover it with paint.

Roller applications have the advantage of high paint utilization but the rollers can only be used efficiently on flat surfaces. For non-flat surfaces, spray techniques are commonly used. However, spray applications have rather low paint utilization. Thus, there is a need for providing a painting technique with increased paint utilization. A further technique that has been previously used to apply paint to objects is curtain coating. In this technique, a curtain of paint is created and the object is painted when it passes through the curtain. Such a curtain-coating technique is described, for instance, in US 5,096,750 or DE 1 817 422. Such curtain-coating devices usually use some pouring head of an elongated shape with a longitudinal slit on its underside or another element for creating a more or less homogeneous curtain of paint.

Known curtain-coating devices have the drawback that the paint curtain's width is predetermined by the width of the pouring head. This width is a compromise between the need for a sufficiently large width to be able to paint differently sized objects, and the fact that the paint curtain tends to get less homogeneous as the width increases. It is therefore an object of the present invention to provide an improved curtain-coating device and method that allow to more flexibly handle differently sized objects, particularly furniture parts. Summary of the invention

This object is achieved with a device according to claim 1. Preferred embodiments are specified in the dependent claims.

According to the invention, two or more spray heads are provided for providing the curtain of paint, each of the spray heads comprising a longitudinal slot through which the paint exits the spray head when forming the curtain of paint. By providing two or more spray heads to form the curtain of paint, the device may more flexibly react to differently sized objects. For instance, only spray heads actually required for painting a certain object may be activated while others may remain inactivated. Furthermore, the total width of the curtain of paint may be determined based on the number of spray heads. Since the curtain of paint is formed by individual spray heads with longitudinal slots of a certain size, the total width of the curtain of paint can arbitrarily be increased without diminishing the homogeneity of the paint curtain. Thus, large objects can also be treated with the device.

In view of the above, the number of spray heads is not particularly limited. Embodiments of the invention may use, for instance, 4 or 6 spray heads for providing the curtain of paint.

The term "curtain of paint" as used herein refers to a film of paint that is formed by the paint exiting the longitudinal slots of one or more of the two or more spray heads. The curtain of paint may particularly fall upon the object under the influence of gravity. Thus, the two or more spray heads may be arranged above the support. The curtain of paint may be a coherent or continuous film formed by the individual films created by the spray heads. Alternatively, the individual films created by the spray heads may not be coherent but interrupted. In this case, the curtain of paint comprises individual paint films created by the respective spray heads of the two or more spray heads. Whether a coherent or interrupted curtain of paint is formed depends on the arrangement of the two or more spray heads, as will be described in further detail below.

The object to be painted may particularly correspond to a piece of furniture or a furniture part. The term "furniture part" as used herein refers to any part of an already assembled or still unassembled piece of furniture. It may also refer to any workpiece that is intended for a subsequent use in manufacturing a piece of furniture, for instance, a wooden board, a hard board (high-density fiber board, HDF), or a medium-density fiber board (MDF). The device, however, may also be used to apply paint on other objects, for example to apply paint on building material.

The support may include a conveying medium, particularly a conveying belt. With the conveying medium, the object may be conveyed or transported at a predetermined speed through the curtain of paint. In this case, the two or more spray heads may particularly be arranged in a fixed position within the device. Alternatively, the two or more spray heads may be movable as well. For instance, the two or more spray heads may be movable in a vertical direction. Through such a movement, the distance to the object arranged on the conveying medium may be varied. Alternatively or additionally, the two or more spray heads may be movable in a direction transverse to the conveying direction of the conveying medium. In this case, the distance from the surface of the conveying medium may remain constant. Through this moveability transverse to the direction of movement of the conveying medium, different parts of a large-scale object may be treated.

The two or more spray heads may be rigidly connected to each other. In other words, the relative position of the spray heads with respect to each other may be fixed. The two or more spray heads may particularly be connected to each other, particularly in a nondestructively detachable way.

The device may further comprise at least one air supply tube for supplying the two or more spray heads with air, particularly pressurized air. The air pressure may particularly be between 1 and 2 bar, particularly above 1 bar, and below or equal to 2 bar.

The device may further comprise at least one paint supply tube for supplying the two or more spray heads with paint, particularly pressurized paint. The paint pressure may be between 1 and 10 bar, particularly above 1 bar, and equal to or less than 10 bar.

The additional usage of air, particularly pressurized air, and/or the usage of pressurized paint allow creating a more homogeneous film. Moreover, paint having a high viscosity may be used. This is in contrast to previous curtain-coating techniques that required paint with low viscosity.

The paint used in the device is not particularly limited. The paint may particularly be a radiation- curable paint, for instance, a UV-curable paint. The paint may be the same as used in conventional roller-coating techniques. The two or more spray heads may be arranged in a row extending perpendicular or transverse to a direction of movement of the object when it is moved through the curtain of paint. The two or more spray heads, thus, may be arranged side-by-side so that the working width of the device is determined by the number of spray heads used and the width of the individual spray heads.

The two or more spray heads may be individually controllable. Thus, each of the two or more spray heads may be separately activated or deactivated. When pressurized air and/or pressurized paint are supplied to the spray heads, the air pressure and/or paint pressure may be individually controllable for each of the two or more spray heads. In this way, the curtain of paint may be adjusted to specific requirements related to a specific object.

The longitudinal slots of at least two of the two or more spray heads may be aligned or offset with respect to each other. In this way, either a continuous or an interrupted curtain of paint may be formed. The relative orientation of the spray heads may be adjustable with respect to each other, particularly continuously or in discontinuous steps.

The longitudinal slots of the two or more spray heads may particularly be arranged in a vertical plane. In this case, a curtain of paint is formed that is arranged within this vertical plane. As a consequence, a coherent or continuous curtain of paint is formed. Alternatively, the longitudinal slots of at least two of the two or more spray heads may be arranged in different vertical planes. In this case, the vertical planes may be offset in the conveying direction of the conveying medium of the support. The spray heads arranged in the different vertical planes may further be offset in a transverse direction. Particularly, when viewing the individual films created by the spray heads in the conveying direction of the conveying medium of the support, the films may be arranged partially but not completely overlapping. In this way, adjacent areas of the object can be painted by the different spray heads without a gap between them.

The longitudinal slot of at least one of the two or more spray heads may be arranged in a plane being inclined with respect to a vertical plane. In this way, front and/or back edges of, for instance, furniture parts may be advantageously painted. The angle between the inclined plane and the vertical plane may be between 0° and 45°, and particularly between 5° and 30°.

Longitudinal slots of at least two of the two or more spray heads may also be arranged in different planes being inclined with respect to each other and to a vertical plane. The different inclined planes may particularly be inclined in different directions. In this way, edges of an object may be painted more flexibly. For instance, the device may comprise two rows of spray heads, each row comprising two or more spray heads, wherein the longitudinal slots of the spray heads of the first row are oriented in a first inclined plane while the longitudinal slots of the spray heads of the second row are arranged in a second, different inclined plane. The first inclined plane may be inclined or angled in a direction opposite to the conveying direction of the convening medium of the support, while the second inclined plane may be inclined or angled in the conveying direction. In this way, all four edges of the object may be painted. Particularly, the front edge may be advantageously painted using the spray heads of the first row while the trailing edge may be advantageously painted by the spray heads of the second row.

The spray heads of the device may each comprise an inlet for the paint and an inlet for air. Alternatively, each spray head may include a single inlet for an air/paint mixture. In this case, the air and the paint may be mixed in a common tank connected to the individual spray heads.

In either case, the spray heads each may further include a hollow space or cavity, wherein the longitudinal slot is arranged at a lower side or bottom of said hollow space or cavity. Thus, paint may be input into a spray head via the input opening and then further transported via the hollow space or cavity towards the longitudinal slot, where the paint exits the spray head to form a paint film of the curtain of paint.

In each of the spray heads, opposing sidewalls at distal ends of the longitudinal slots may be inclined so that the wall distance widens towards the longitudinal slot. In this way, the film of paint exiting the longitudinal slot may also widen or fan out at its edges so that the overlap between neighboring films of paints exiting from neighboring spray heads may be improved. The "distal ends" of the longitudinal slot denote herein those sides of the longitudinal slot that have the largest distance from each other. The opposing sidewalls may particularly be walls of the above-mentioned cavity or hollow space.

The device may further comprise a paint recovery system for collecting unused paint and resupplying the collected unused paint at least partially to the two or more spray heads. The term "unused paint" herein refers to the paint of the curtain of paint that is not applied to the object. This unused paint may be collected in a receptacle. This receptacle may be positioned below the support, particularly, wherein the support comprises a gap below the two or more spray heads so that in operation the curtain of paint extends through the gap. When an object is moved through the curtain of paint, paint is applied to the object in those areas where the curtain of paint hits the object. Otherwise, the curtain of paint falls through the gap of the support and is collected by the receptacle. From this receptacle, the paint may be resupplied to the two or more spray heads, for instance, using a pump. The paint recovery system may alternatively or additionally comprise a conveying belt having a conveying direction perpendicular to the conveying direction of the conveyer medium of the support and being arranged below the two or more spray heads. The unused paint in this case is transported with the conveying belt of the paint recovery system towards a cleaning element, for instance, at a lower side thereof. Via the cleaning element, the unused paint is removed from the conveying belt and then further resupplied to the two or more spray heads, again, for instance, using a pump.

The above-described two or more spray heads may form a first set of spray heads, and the device may further comprise a second set of spray heads comprising two or more spray heads for providing a second curtain of paint. The first set of spray heads and the second set of spray heads may be arranged at different positions within a processing line. Particularly, the second set of spray heads may be arranged downstream of the first set of spray heads when the support comprises a conveying medium transporting the object in a predetermined conveying direction. Between the first set of spray heads and the second set of spray heads, a sanding device, a curing device for curing radiation-curable paint, and/or a roller-coating device may be arranged in the processing line. The curing device may particularly be a UV-radiation source. The roller-coating device may be configured such that it removes paint from a predetermined area of the object. In this way, the amount of paint applied to different areas of the object may be adjusted. This may be particularly useful if the object is an MDF board with grooves or similar surface structures. Any grooves within the MDF board yield a material with lower density as a surface layer of the object. Lower density material, however, usually requires more paint than high-density material. The roller-coating device, thus, may be configured to remove paint from high-density areas. Thus, the amount of paint applied to a surface of an object may be adjusted or controlled depending on the density of the material of the object in a given surface area. The invention further provides a method for applying paint on an object, particularly a furniture part, according to claim 15. The method may be performed with an above-described device.

The method may particularly comprise individually controlling the two or more spray heads so that a desired curtain of paint is formed. Controlling the two or more spray heads may comprise selectively activating and/or deactivating one or more of the two or more spray heads. Alternatively or additionally, controlling the two or more spray heads may comprise controlling the air pressure or paint pressure of pressurized air and pressurized paint supplied to the two or more spray heads. Applying paint on the object may further comprise sanding predetermined surface areas of the object and subsequently applying paint by transversing the object through the curtain of paint. After moving the object through the curtain of paint, the method may further comprise curing the paint using a curing device, when said paint is a radiation-curable paint, for instance, a UV- curable paint. The method may further comprise removing paint from predetermined areas of the object after moving the object through the curtain of paint, wherein removing the paint is particularly performed using a roller-coating device.

Brief description of the drawings

Advantageous embodiments will now be described in combination with the enclosed figures.

Figure 1 shows the basic setup of the device according to an embodiment of the invention;

Figure 2 illustrates further details of a possible device according to an embodiment of the invention;

Figures 3A and 3B show two exemplary arrangements of spray heads of a device according to an embodiment of the invention;

Figures 4A and 4B illustrate different exemplary arrangements of spray heads of a device according to an embodiment of the invention; and

Figure 5 shows a cross section of an exemplary spray head used in a device according to an embodiment of the invention.

Detailed description of preferred embodiments

The Figures illustrate devices according to embodiments of the invention applying paint on furniture parts. Other objects than furniture parts are conceivable as well, particularly building material, e.g. for houses or other items.

As seen from Figure 1 , the exemplary device for applying paint on furniture parts comprises a support 1 for supporting a furniture part 2, such as a wooden board. The wooden board 2 may further be used in the production of a piece of furniture, such as a cupboard, a bed, or another item. The support comprises a conveying medium that is subdivided into two conveying elements 3, 3' as illustrated in Figure 1. Each of the conveying elements 3, 3' comprises a conveying belt driven by respective driving roles 4, 4'. The conveying direction of the support 1 is illustrated by an arrow A.

The two conveying elements 3, 3' are spaced apart from each other, so that a gap is formed between them. Overlapping with said gap a set 5 of spray heads 6 is provided above the support 1. This set 5 of spray heads 6 forms a curtain of paint 7 that falls through the gap formed between the conveying elements 3, 3'. The spray heads 6 extend in a direction B, transverse to the conveying direction A. Thus, the furniture part 2 may be conveyed through the curtain of paint 7 so that at least a part of its surface is painted thereby.

That set 5 of spray heads 6 is mounted at a mounting assembly 8. The set 5 of spray heads 6 may be movable in the transverse direction B. Each of the spray heads 6 may be individually controlled so as to adapt the transverse extension of the curtain of paint 7.

As illustrated in Figure 1 , an air supply tube 9 and a paint supply tube 10 are provided for supplying the spray heads 6 with air, particularly pressurized air, and paint, particularly pressurized paint. Each of the spray heads 6 comprises a longitudinal slot (not shown in detail in Figure 1) through which the paint exits the spray heads 6 when forming the curtain of paint 7.

The extension of the longitudinal slot in the conveying direction A may be between 0.03 and 0.1 mm. The extension of the longitudinal slot in the transverse direction B may be 25 to 50 mm.

The longitudinal slot of the spray heads 6 may be arranged at a height of 3 to 6 mm above the upper surface of the furniture part 2. For adjusting the height of the set 5 of spray heads 6, the mounting assembly 8 may be configured such that the vertical position of the set 5 of spray heads 6 is adjustable. Particularly, a linear motor may be provided to control the vertical position of the spray heads 6 above the support 1. The vertical position of the spray heads 6 may be adjusted depending on the furniture part 2 that is to be treated. The air pressure of the air supplied via air supply tube 9 may be 1 to 2 bar and the paint pressure may be between 1 and 10 bar.

This setup allows providing a pressurized curtain of paint. The width (extension in the transverse direction B) of the curtain of paint 7 is determined by the number of spray heads 6. In the example of Figure 1 , four spray heads are shown. However, any number of spray heads greater than two may be chosen. Particularly, two to ten spray heads may be provided. In the example shown in Figure 1 , a continuous curtain of paint 7 is formed in one vertical plane, as all spray heads 6 are activated. An interrupted curtain of paint 7 may also be formed (not shown) if, for instance, one or both of the inner spray heads 6 of the set 5 are deactivated while the outer spray heads 6 are active. Figure 2 shows further details of a possible setup of a device according to an embodiment of the present invention. The exemplary device comprises a support including several conveying elements 3, each of which being a conveying belt in this example. A first set 5 of spray heads is provided, forming a curtain of paint 7, and a second set 11 of spray heads is provided downstream (with regard to the conveying direction A), forming a second curtain of paint 12. Each of the sets 5, 1 1 of spray heads is provided with a hood 13 to protect the surroundings from overspray.

Below each of the first set 5 and the second set 1 1 of spray heads, a paint recovery system 17, 18 is shown. This paint recovery system 17, 18 may be used for collecting unused paint. The paint recovery system 17 below the first set 5 of spray heads comprises a conveying belt arranged perpendicular to the conveying belts of the conveying elements 3 of the support. Unused paint falls on the conveying belt of the paint recovery systems 17. With a cleaning element (not shown) the paint may be removed from the conveying belt of the paint recovery system 17 and resupplied to the first set 5 of spray heads using a pump (not shown).

An alternative paint recovery system 18 is shown below the second set 1 1 of spray heads. In this case, the unused paint is received by a paint receptacle provided below the gap between two adjacent conveying elements 3. From said receptacle, the paint may be resupplied to the second set 11 of spray heads using another pump (not shown) or the same pump as used for paint recovery system 17.

Upstream of the first set 5 of spray heads, a sanding device 14 is arranged to treat predetermined areas of a furniture part. Another similar sanding device 14 may be provided immediately upstream of the second set 1 1 of spray heads.

Immediately downstream of the first set 5 of spray heads and the second set 11 of spray heads, a respective roller-coating device is shown. These roller-coating devices 15 each include a roll comprising a surface material configured to absorb paint. The rolls of the roller-coating devices 15 may be configured to remove paint from predetermined surface areas of the furniture part 2. Thus, the roller-coating devices 15 are not supplied with paint as in known roller-coating devices. In this way, the amount of paint applied to certain surface areas of the furniture part may be controlled. For instance, surface areas with a higher density may be provided with less paint than surface areas where the density of the material is lower.

Further downstream of the roller-coating devices 15, a curing device 16 may be provided for curing radiation-curable paint, such as UV-curable paint. As illustrated in Figure 2, the device according to an embodiment of the invention provides a very short coating line that can be operated at high speed (up to 40 m/min) and low coating cost in view of efficient paint usage.

The setup shown in Figure 2 is purely exemplary. The roller-coating devices 15 and/or the sanding devices may not be provided in alternative setups. The curing devices 16 need to be provided only when a radiation-curable paint is used.

For illustrative purposes, two different paint recovery systems 17, 18 are illustrated in Figure 2. However, the same paint recovery system may also be used throughout a device.

Finally, while Figure 2 shows two sets 5, 11 of spray heads, it should be understood that a single set of spray heads or more than two sets of spray heads may also be provided. While in the exemplary setup the support is configured such that the furniture part may be moved with respect to a stationary set of spray heads, in an alternative setup it is possible that the set of spray heads is also movable with regard to the furniture part. Since movement of the set of spray heads affects the form and quality of the curtain of paint, however, it is preferable that in operation the set of spray heads remains fixed and the furniture part is moved with regard to the stationary set of spray heads.

Figures 3A and 3B show different arrangements of the spray heads of a given set of spray heads.

Particularly, Figure 3A shows an example in which the spray heads 6 are arranged side-by-side in a single row. In this case the longitudinal slots of the spray heads 6 are aligned with each other and all arranged in the same vertical plane 19. This setup allows for forming a continuous and coherent curtain of paint within the vertical plane 19.

Figure 3B shows an alternative setup, according to which the spray heads 6 are arranged offset to each other. Particularly, three of the spray heads 6 are arranged in a first vertical plane 19 and three of the spray heads 6 are arranged in a parallel vertical plane 20. The spray heads are staggered such that the paint films output by the individual spray heads 6 overlap on the furniture part so that a continuous application of paint may be achieved. In a non-illustrated front view of the spray heads 6, the spray heads of the second vertical plane 20 are, thus, arranged so as to overlap the gaps between the spray heads 6 arranged in the first vertical plane 19, as well as partly overlapping the two spray heads 6 of the first vertical plane 19 adjacent to the respective gap.

Figures 4A and 4B show perspective views of alternative arrangements of spray heads of a given set of spray heads.

Particularly, in Figure 4A, the spray heads of a set 5 of spray heads are alternatively arranged in a first inclined plane and a second inclined plane, respectively. The planes in which the longitudinal slots of the spray heads are arranged are inclined with regard to a vertical plane at an angle between 0° and 45°, particularly between 5° and 30°. This arrangement allows to advantageously paint the front edge and trailing edge of the furniture part.

An alternative arrangement in two inclined planes is illustrated in Figure 4B. In this case, each of the two inclined planes comprises six spray heads arranged immediately next to each other. This setup allows to paint all four edges of a given furniture element.

Figure 5 illustrates a cross section through an exemplary spray head 6 according to an embodiment of the invention. The longitudinal slot 21 is shown at a lower side of the spray head 6. Opposing sidewalls 22, 23 of the spray head 6 at distal ends of the longitudinal slot 21 are inclined so that the wall distance widens towards the longitudinal slot 21. This specific implementation of the spray head 6 allows forming uniform painting of the furniture part, since the paint films output by neighboring spray heads 6 will overlap, thereby forming a coherent or continuous curtain of paint. Assuming a perpendicular shape of the side walls 22, 23, gaps would be formed between the individual films output by the respective spray heads 6, thus forming an interrupted cover of paint on the furniture part. The spray head 6 as shown in Figure 5 may particularly be used in the setup of Figures 3A, 4A, and 4B. In Figure 3B, a spray head 6 with vertical sidewalls 22, 23 may also be used, since the overlap between the films of paint output by the respective spray heads 6 is obtained in view of the spatial arrangement of the spray heads 6 relative to each other.

Although the previously discussed embodiments and examples of the present invention have been described separately, it is to be understood that some or all of the above-described features can also be combined in different ways. The above discussed embodiments are particularly not intended as limitations, but serve as examples, illustrating features and advantages of the invention.

Claims

1 A device for applying paint on objects comprising: a support (1) for supporting an object (2); and two or more spray heads (6) for providing a curtain of paint (7); wherein the support (1) and/or the two or more spray heads (6) are movable such that the object (2) can be moved at least partially through the curtain of paint (7); and wherein each of the spray heads (6) comprises a longitudinal slot (21) through which the paint exits the spray head (6) when forming the curtain of paint (7).

2. The device according to claim 1 , further comprising at least one air supply tube (9) for supplying the two or more spray heads (6) with air, particularly pressurized air.

3. The device according to claim 1 or 2, further comprising at least one paint supply tube (10) for supplying the two or more spray heads (6) with paint, particularly pressurized paint.

4. The device according to any one of the preceding claims, wherein the two or more spray heads (6) are arranged in a row extending perpendicular to a direction of movement of the object (2) when it is moved through the curtain of paint (7).

5. The device according to any one of the preceding claims, wherein the two or more spray heads (6) are controllable individually.

6. The device according to any one of the preceding claims, wherein the longitudinal slots (21) of at least two of the two or more spray heads (6) are aligned or offset with respect to each other.

7. The device according to any one of the preceding claims, wherein the longitudinal slots (21) of the two or more spray heads are arranged in a vertical plane (19).

8. The device according to any one of claims 1 to 6, wherein the longitudinal slots (21) of at least two of the two or more spray heads (6) are arranged in different vertical planes (19, 20).

9. The device according to any one of claims 1 to 6, wherein the longitudinal slots (21) of at least one of the two or more spray heads (6) is arranged in a plane being inclined with respect to a vertical plane.

10. The device according to claim 9, wherein the longitudinal slots (21) of at least two of the two or more spray heads (6) are arranged in different planes being inclined with respect to each other and to a vertical plane.

1 1. The device according to any one of the preceding claims, wherein, in each of the spray heads (6), opposing side walls (22, 23) at distal ends of the longitudinal slot (21) are inclined so that the wall distance widens towards the longitudinal slot (21).

12. The device according to any one of the preceding claims, further comprising a paint recovery system (17, 18) for collecting unused paint and re-supplying the collected unused paint at least partially to the two or more spray heads (6).

13. The device according to any one of the preceding claims, wherein the support (1) includes a conveying medium, particularly a conveying belt.

14. The device according to any one of the preceding claims, wherein the two or more spray heads (6) form a first set (5) of spray heads, wherein the device further comprises a second set (11) of spray heads comprising two or more spray heads for providing a second curtain of paint (12); and wherein between the first set (5) of spray heads and the second set (1 1) of spray heads a sanding device (14), a curing device (16) for curing radiation curable paint, and/or a roller coating device (15) are arranged in a processing line.

15. A method for applying paint on an object comprising: providing a device according to one of the preceding claims; creating a curtain of paint using the two or more spray heads of the device; and moving the object trough the curtain of paint by moving the support and/or the two or more spray heads.