Rotary atomizer and corresponding cleaning method

Abstract

The invention relates to a rotary atomizer (1) for spraying a spray jet of a coating agent (e.g., paint) onto a component (e.g., a motor vehicle body component), comprising * an atomizer housing (4) having a tube (5), * a deflecting air ring at the distal end of the tube (5) in order to blow out a deflecting air jet for forming the spray jet of the coating agent, * an outer charging ring (9) for electrostatically charging the sprayed coating agent, the outer charging ring (9) being exchangeably mounted on the exterior of the atomizer housing (4), * a tube shield (11) on the outer charging ring (9), the tube shield (11) at least partly annularly surrounding the tube (5) of the atomizer housing (4), thereby protecting against fouling by the sprayed coating agent, while the tube shield (11) has, on the inner face thereof, an annular contact region (13) contacting the tube (5) and / or the deflecting air ring, and * a blowing device for blowing air on the annular contact region (13) on the inner face of the tube shield (11), in particular after a cleaning process of the rotary atomizer (1) in an atomizer cleaning device. The invention also relates to a corresponding cleaning method.

Description

[0001] DESCRIPTION

[0002] Rotary atomizer and associated cleaning process

[0003] Technical field of the invention

[0004] The invention relates to a rotary atomizer for spraying a spray jet of a coating material (e.g., paint) onto a component (e.g., a vehicle body component). The invention further relates to a cleaning method for cleaning such a rotary atomizer.

[0005] Background of the invention

[0006] In modern paint shops for painting automotive body components, rotary atomizers are typically used as application devices. These are guided by a multi-axis painting robot over the surfaces of the body components to be painted, emitting a spray jet of the paint. However, some of the sprayed paint does not adhere to the body components but forms a disruptive overspray, which, among other places, settles on the outside of the atomizer housing, leading to contamination of the rotary atomizer. Therefore, it is known in the art to regularly clean the rotary atomizers during operation, which is particularly important when changing colors, as otherwise paint transfer would occur.For this purpose, the rotary atomizers are inserted by the painting robot into an atomizer cleaning device, as known, for example, from DE 10 2004061 322 Al, DE 10 2019 107 847 Al or WO 2015 / 169432 Al. Various cleaning steps are then carried out in the atomizer cleaning device. First, paint residues are rinsed out of the rotary atomizer and can then be disposed of by the cleaning device. Second, residues of cleaning agent and paint are blown out of the rotary atomizer with compressed air. In addition, the atomizer housing is sprayed externally with cleaning agent and thus cleaned.

[0007] It is also known from the prior art to electrostatically charge the paint spray while the vehicle body components to be painted are electrically grounded, thereby increasing the application efficiency and correspondingly reducing disruptive overspray. External charging rings can be used for this purpose. These rings are mounted externally on the atomizer housing of the rotary atomizer and may have several finger electrodes projecting diagonally forward to electrostatically charge the spray. Such external charging rings can be easily replaced, so that a ring contaminated by overspray can be replaced with a clean one.The problem here, however, is that the external charging ring does not completely cover the tube of the atomizer housing, meaning that the tube can still be contaminated by overspray during operation and therefore requires time-consuming cleaning. Several approaches to solving this problem are known in the prior art, which are briefly described below.

[0008] One approach to solving this problem is known from EP 3 831499 Al. This patent application discloses a rotary atomizer in which air is blown out of the annular contact area (annular gap) between the external charging ring and the atomizer housing during operation to protect the atomizer housing tube from contamination. However, the atomizer housing tube remains exposed, and contamination of the tube is prevented solely by the escaping air.

[0009] Another approach to solving this problem is known from WO 2023 / 036679 Al. This patent application discloses a rotary atomizer with a replaceable external charging ring, wherein a tube shield is arranged on the external charging ring. This shield projects distally from the mounting ring of the external charging ring and largely covers the tube of the atomizer housing, thereby protecting it from contamination by overspray. When the external charging ring is replaced, the externally contaminated tube shield is also replaced with a clean one, thus eliminating the need to clean the tube of the atomizer housing in the area protected by the tube shield.

[0010] However, a problem with this solution using a tube shield is that the tube shield and the atomizer housing tube enclose an annular contact area, also known as the interface, which cannot be completely sealed. This annular contact area can become contaminated during operation by the sprayed-off paint and is difficult to clean and dry from the outside. Contamination penetrates the annular contact area even more quickly if the rotary atomizer is still wet in this area after cleaning. Finally, reference should be made to the prior art patents JP 2003 - 236416 A and DE 102021 123081 A.

[0011] Description of the invention

[0012] The invention is therefore based on the objective of creating a correspondingly improved rotary atomizer and an associated cleaning process.

[0013] This problem is solved by a rotary atomizer according to the invention or a corresponding cleaning method according to the independent claims.

[0014] The rotary atomizer according to the invention is designed to deliver a spray jet of a coating material onto a component, as is known per se from the prior art and therefore does not require further description. Preferably, the applied coating material is a paint, while the coated component is preferably a motor vehicle body component. However, the invention is not limited to the aforementioned examples (paint or motor vehicle body components) with regard to either the type of coating material or the type of coated component, but is also fundamentally suitable for coating other types of components with other types of coating materials.

[0015] In accordance with the known rotary atomizer described above, the rotary atomizer according to the invention also has an atomizer housing with a tube that preferably tapers continuously in the distal direction.

[0016] Furthermore, the rotary atomizer according to the invention, in accordance with the prior art described above, also features a guiding air ring arranged at the distal end of the tube to direct a guiding air jet for shaping the spray pattern of the coating material. Such guiding air rings are known per se from the prior art and therefore do not need to be described in detail. It should be noted, however, that the guiding air ring can be a separate component that is joined to the atomizer housing. Alternatively, it is also possible for the tube to merge seamlessly into the guiding air ring at its distal end.

[0017] Furthermore, the rotary atomizer according to the invention, in accordance with the prior art described above, also has an external charging ring for electrostatically charging the sprayed coating material, wherein the external charging ring is interchangeably mounted on the outside of the atomizer housing. In practice, the external charging ring has several electrodes that are charged to a high-voltage potential during operation. For example, these can be so-called finger electrodes that project obliquely outwards and distally from the external charging ring in a finger-like manner.

[0018] Furthermore, the rotary atomizer according to the invention features a tube shield on the external charging ring, as is also known, for example, from the aforementioned patent application WO 2023 / 036679 Al, so that the content of this earlier patent application is fully applicable to the present description with regard to the function and construction of the tube shield. The tube shield encloses the tube of the atomizer housing at least partially in an annular form and thereby protects the tube from contamination by the disruptive overspray of the sprayed coating material. On its inner side, the tube shield forms an annular contact area with the tube of the atomizer housing and / or with the steering air ring, this annular contact area being also referred to in the relevant technical language as an interface, since it separates the external charging ring with the tube shield from the actual atomizer.It has already been mentioned above that this interface (ring-shaped contact area) between the tube shielding on the one hand and the tube or steering air ring on the other hand is prone to contamination and is difficult to dry.

[0019] The invention therefore provides a blow-out device to blow out this annular contact area between the tube shield and the tube or guide air ring with air, particularly after cleaning the rotary atomizer in an atomizer cleaning device, in order to then dry the annular contact area. Blowing out the annular contact area (interface) on the inside of the tube shield also prevents or eliminates contamination of this annular contact area.

[0020] It should be noted that the invention does not only claim protection for a rotary atomizer in which the tube shield seals against the outer surface of the tube or the steering air ring. Rather, the invention also claims protection for a corresponding rotary atomizer with an annular gap between the tube shield and the outer surface of the tube or the steering air ring. In the preferred embodiment of the invention, however, the tube shield partially seals against the outer surface of the tube or the steering air ring, leaving several grooves distributed around its circumference through which compressed air can be expelled, as will be described in detail below.

[0021] In a preferred embodiment of the invention, the blow-off device has several blow-off nozzles for blowing out air. The blow-off nozzles are preferably arranged in a ring-shaped pattern with respect to the axis of rotation of the rotary atomizer, and in particular at equidistant intervals. The number of blow-off nozzles can be greater than 10, 20, 50, or 100 so that the annular contact area (interface) is cleaned as uniformly as possible over its entire circumference. Alternatively, however, it is also possible that no separate blow-off nozzles are provided, but rather a continuous, ring-shaped blow-off slot running uninterrupted around the circumference.

[0022] The discharge nozzles are preferably supplied with air from several discharge ducts. Preferably, each discharge nozzle is assigned to one of the discharge ducts, meaning each nozzle is supplied with air from one of the discharge ducts. Alternatively, however, several discharge nozzles can be supplied with air from a single common discharge duct. It is even possible to use a single discharge duct that supplies all discharge nozzles with air.

[0023] In a preferred embodiment of the invention, the exhaust channels are grooves in the inner wall of the tube shield. These grooves are preferably arranged distributed around the circumference of the tube shield, and preferably equidistantly. Between the individual grooves, the inner wall of the tube shield rests against the outer wall of the tube and / or the steering air ring, while the grooves are bounded internally by the outer wall of the tube and / or the steering air ring. However, instead of such grooves, the exhaust channels can also be, for example, closed conduits running within the tube shield.

[0024] The exhaust nozzles preferably all have a common exhaust cross-section that is larger than 0.5 mm. 2 , 1 mm 2 , 2 mm 2 , 5 mm 2 , 10 mm 2 or 20 mm 2In contrast, each individual discharge nozzle preferably has a nozzle cross-section that is smaller than 1 mm². 2 , 0.5 mm 2 , 0.2 mm 2 , 0.1 mm 2 or 0.05 mm 2 Furthermore, it should be mentioned that the exhaust nozzles can all have the same nozzle cross-section. However, it is also possible for the exhaust nozzles to have different nozzle cross-sections, for example, two or three different nozzle cross-sections.

[0025] The tube shield of the rotary atomizer according to the invention can have a seal at its distal end to seal the annular contact area between the tube shield and the tube of the rotary atomizer, as is known per se from the aforementioned patent application WO 2023 / 036679 Al, so that the content of this earlier patent application is fully incorporated into the present description with regard to the seal. Preferably, this seal is designed as a sealing ring and consists of an electrically insulating material (e.g., PTFE: polytetrafluoroethylene).

[0026] Furthermore, it should be noted that the tube shield preferably covers a large portion of the outer surface of the tube, thereby protecting it from contamination by overspray. The tube shield therefore extends distally along the axis of rotation of the rotary atomizer, preferably beyond the external charging electrodes of the external charging ring. Moreover, the tube shield preferably has a length of at least 2 cm, 4 cm, 6 cm, 8 cm, or at least 10 cm along the axis of rotation of the rotary atomizer. The tube shield therefore preferably covers at least 10%, 20%, 30%, or at least 50% of the outer surface of the tube. This also distinguishes the invention from the prior art described above according to EP 3 831499 A1, in which the external charging ring, although it does not have a tube shield, itself covers at least a small portion of the outer surface of the tube.

[0027] In one embodiment of the invention, the tube shield is integrally formed with the external charging ring and thus consists of the same material as the external charging ring or its mounting. In another embodiment, the tube shield forms a separate component that is attached to the external charging ring or its mounting ring and optionally consists of a different material than the external charging ring or its mounting ring.

[0028] In addition to the rotary atomizer according to the invention described above, the invention also claims protection for a cleaning method for cleaning such a rotary atomizer. The cleaning method according to the invention is briefly described below.

[0029] In accordance with the known cleaning methods described above, the cleaning method according to the invention provides that the rotary atomizer is inserted into an atomizer cleaning device for cleaning, as is known, for example, from the aforementioned patent applications DE 102004061322 Al or WO 2015 / 169432 Al, so that the content of these patent applications is fully applicable to the present description with regard to the function and construction of the atomizer cleaning device. Preferably, the rotary atomizer is inserted into the atomizer cleaning device by a multi-axis coating robot.

[0030] The rotary atomizer is then cleaned in the atomizer cleaning device, as is known from the prior art. The following cleaning steps can be performed for this purpose:

[0031] • Spray the outside of the atomizer housing with dish soap to clean the rotary atomizer externally,

[0032] • Rinsing out coating agent residues from the rotary atomizer into the atomizer cleaning device to clean the inside of the rotary atomizer, and / or

[0033] • Blowing out coating agent residues and detergent residues from the rotary atomizer into the atomizer cleaning device.

[0034] Finally, the cleaning method according to the invention provides, in accordance with the prior art described at the outset, that the rotary atomizer is removed from the atomizer cleaning device by the coating robot pulling the rotary atomizer out of the atomizer cleaning device.

[0035] The cleaning method according to the invention is characterized in that, during the cleaning of the rotary atomizer in the atomizer cleaning device, the ring-shaped contact area on the inside of the tube shield is blown out with air.

[0036] The blowing out of the annular contact area of ​​the rotary atomizer preferably takes place when the rotary atomizer is being cleaned in the atomizer cleaning device. Furthermore, the blowing out of the annular contact area preferably continues while the rotary atomizer is being moved out of the atomizer cleaning device by the coating robot.

[0037] When the rotary atomizer is withdrawn from the atomizer cleaning device at the end of a cleaning process, it is preferably stopped at a holding point, particularly for a holding time of 1 to 10 seconds, 2 to 5 seconds, or 3 seconds. At this holding point, the rotary atomizer can then be blown with drying air from the outside to dry it, especially at the annular contact area (interface) on the inside of the tube shield. The holding point is therefore preferably chosen so that the drying air blown from the outside hits the annular contact area to dry it.

[0038] The blowing on the rotary atomizer can also continue while the rotary atomizer is being removed from the atomizer cleaning device.

[0039] Other advantageous embodiments of the invention are characterized in the dependent claims or are explained in more detail below together with the description of the preferred embodiments of the invention with reference to the figures.

[0040] Brief description of the drawings

[0041] Figure 1 shows a perspective view of a rotary atomizer according to the invention.

[0042] Figure 2 shows a sectional view of the rotary atomizer from Figure 1.

[0043] Figure 3 shows a perspective view of the tube shielding of the rotary atomizer from Figures 1 and 2.

[0044] Figure 4 shows a flowchart to illustrate the cleaning process according to the invention.

[0045] Detailed description of the drawings

[0046] In the following, a preferred embodiment of a rotary atomizer 1 according to the invention is described, as shown in Figures 1 to 3.

[0047] The rotary atomizer 1 according to the invention is used for painting vehicle body components with a paint and is typically guided over the component surfaces of the vehicle body components to be painted by a painting robot, the painting robot itself not being shown for the sake of simplicity. A turbine shaft 2 is rotatably mounted in the rotary atomizer 1, and a bell-shaped plate can be mounted at the distal end of the turbine shaft 2, as is known from the prior art. For example, the bell-shaped plate can simply be screwed onto the distal end of the turbine shaft 2; however, other fastening options are also conceivable for attaching the bell-shaped plate to the turbine shaft 2.In operation, the turbine shaft 2 rotates at high speed around a rotational axis 3, the turbine shaft 2 being driven by a compressed air turbine, which is omitted in Figure 2 to draw attention to the essential details of the rotary atomizer 1.

[0048] Furthermore, the rotary atomizer 1 has an atomizer housing 4 which transitions distally into a tube 5 and finally into a steering air ring 6.

[0049] The steering air ring 6 enables the blowing out of steering air, which then strikes the spray jet of the sprayed paint from behind to shape it, as is known from the prior art. In this embodiment, the steering air ring 7 has two concentric steering air nozzle rings, each of which has a plurality of steering air nozzles arranged equidistantly in the circumferential direction. With regard to the design and function of the steering air ring 6, reference is made by way of example to the earlier patent applications WO 2009 / 149950 Al, WO 2023 / 057407 Al and WO 2008 / 068005 Al, the content of which is fully incorporated into the present description with regard to the function and design of the steering air ring 6.

[0050] Furthermore, it should be mentioned that the steering air ring 6 is an integral component of the rotary atomizer 1. However, it is also possible to design the steering air ring 6 as a separate component, which is then mounted on the rotary atomizer 1. Several steering air channels 7, 8 run through the steering air ring 6, supplying steering air to the inner and outer steering air nozzle rings of the steering air ring 6, respectively.

[0051] Furthermore, the rotary atomizer 1 according to the invention has an external charging ring 9 for electrostatically charging the lacquer sprayed from the bell-shaped plate. For this purpose, several finger electrodes 10 are used, which project obliquely forward in a distal direction from the external charging ring 9 and each contain an embedded electrode that is at a high-voltage potential during operation.

[0052] A tube shield 11 is arranged at the distal end of the external charging ring 9. This shield extends distally from the external charging ring 9 and encloses the tube 5 of the atomizer housing 4, thus protecting it from contamination by overspray. When the external charging ring 9 is replaced, the contaminated tube shield 11 can also be replaced with a clean one, eliminating the need to clean the tube 5 of the atomizer housing 4 in this area. The tube shield 11 extends distally beyond the finger electrodes 10 of the external charging ring 9, covering a large portion of the outer surface of the tube 5. The tube shield 11 can be permanently attached to the external charging ring 9, for example, by a screw connection or as a single piece.

[0053] At the distal end of the tube shield 11, an annular seal 12 is arranged, which rests sealingly on the outer surface of the steering air ring 6 at the transition to the tube 5 of the atomizer housing 4.

[0054] The tube shield 11 encloses an annular contact area 13 (interface) with the tube 5 of the atomizer housing 4, into which cleaning agent can penetrate during cleaning of the rotary atomizer 1 in an atomizer cleaning device. The invention therefore provides to blow out this annular contact area 13 with air to prevent or eliminate wetting with cleaning agent. For this purpose, several groove-shaped blow-off channels 14 are located in the inner wall of the tube shield 11, which are arranged equidistantly around the circumference and open into blow-off nozzles 15.

[0055] The blow-out nozzles 15 are supplied with compressed air via the blow-out channels 14, whereby the compressed air supply of the outlet channels 14 is otherwise not shown in further detail and can be carried out in a conventional manner.

[0056] Blowing out the annular contact area 13 at the interface between the tube shield 11 and the tube 5 of the atomizer housing 4 thus prevents or eliminates overspray in this area. Furthermore, blowing out the annular contact area 13 allows it to dry after a cleaning process.

[0057] The following describes the flowchart according to Figure 4, which illustrates the cleaning process according to the invention.

[0058] In a first step S1, the rotary atomizer 1 is inserted by the associated painting robot through an insertion opening into the atomizer cleaning device, as is known from the prior art (see DE 10 2004 061 322 Al, DE 10 2019 107 847 Al, WO 2015 / 169432 Al)

[0059] In a further step S2, the inlet opening of the atomizer cleaning device is sealed to separate the interior of the atomizer cleaning device from the paint booth. This seal can be achieved, for example, by a conventional sealing ring or by an air blow ring that blows a curtain of barrier air across the inlet opening, as is known from the prior art.

[0060] In the next step S3, various actions then take place while the rotary atomizer 1 is in the atomizer cleaning device.

[0061] Firstly, the rotary atomizer 1 is cleaned in the atomizer cleaning device by the following cleaning steps:

[0062] • Spraying the rotary atomizer 1 from the outside with a dish soap (cleaning agent), • Rinsing out paint residue from the rotary atomizer 1 and

[0063] • Blowing out paint residue and detergent residue from the rotary atomizer 1 using compressed air.

[0064] On the other hand, the annular contact area 13 (interface) between the tube shielding 11 and tube 5 or steering air ring 6 is also blown out with compressed air to prevent or eliminate contamination of the annular contact area 13 (interface) and to dry the annular contact area 13.

[0065] In the next step S4, the rotary atomizer 1 is then pulled out of the atomizer cleaning device by the painting robot. During this process, the blowing out of the annular contact area 13 between the tube shield 11 and tube 5 or steering air ring 6 continues. Furthermore, while the rotary atomizer 1 is being pulled out of the atomizer cleaning device, it is dried by blowing compressed air onto it from the outside.

[0066] In a further step S5, the rotary atomizer 1 is stopped at a holding point in the atomizer cleaning device. At this holding point, the annular contact area 13 (interface) between the tube shield 11 and the tube 5 or the steering air ring 5 is blown with compressed air to dry it. For this purpose, the rotary atomizer 1 can be held at the holding point for approximately 3 seconds. Furthermore, the annular contact area 13 between the tube shield 11 and the tube 5 or the steering air ring 6 is also blown out at this holding point. Finally, the rotary atomizer 1 is also dried at this holding point by blowing compressed air onto it.

[0067] In the next step S6, the rotary atomizer 1 is then pulled further out of the atomizer cleaning device until a drying point is reached, at which point the drying of the rotary atomizer 1 is stopped.

[0068] Finally, in step S7, the rotary atomizer 1 is completely withdrawn from the atomizer cleaning device, after which the cleaning process is completed.

[0069] The invention is not limited to the preferred embodiments described above. Rather, the invention allows for a multitude of variants and modifications, which also fall within the scope of protection. Furthermore, the invention also claims protection for the features of the dependent claims independently of the respective referenced claims and, in particular, even without the features of the independent claims. The invention thus comprises various aspects of the invention that enjoy independent protection.

[0070] Advantages of the invention

[0071] The invention enables the blowing out of the annular contact area (interface) between the tube shield on the one hand and the tube or the steering air ring of the rotary atomizer on the other, which is particularly possible during a drying process after cleaning. This allows for fully automatic cleaning of the entire atomizer area. The blowing device according to the invention thus enables drying of the annular contact area (interface) or the removal of residual dirt in the annular contact area, after which an external charging ring, together with the tube shield, can be replaced with a new external charging ring or a different type of external charging ring. This enables a fully automatic booth concept in which the external charging ring can be automatically changed within the paint booth.

[0072] 1 rotary atomizer

[0073] 2 Turbine shaft of the rotary atomizer for mounting a bell plate on the turbine shaft

[0074] 3 Rotation axis of the rotary atomizer

[0075] 4 Atomizer housings of the rotary atomizer

[0076] 5 Tube of the atomizer housing

[0077] 6 Steering air ring of the rotary atomizer

[0078] 7, 8 steering air channels in the steering air ring for supplying steering air

[0079] 9 external charging ring

[0080] 10 finger electrodes of the external charging ring

[0081] 11 Tube shielding for shielding the tube of the atomizer housing

[0082] 12 Sealing the tube shield

[0083] 13 Ring-shaped contact area between tube shielding and tube of the atomizer housing

[0084] 14 exhaust channels in the inner wall of the tube shield

[0085] 15 air outlet nozzles for blowing out air

Claims

REQUIREMENTS 1. Rotary atomizer (1) for spraying a spray jet of a coating material onto a component, in particular for painting motor vehicle body components with a paint, with a) an atomizer housing (4) with a tube (5), b) a steering air ring at the distal end of the tube (5) to blow out a steering air jet to shape the spray jet of the coating material, c) an external charging ring (9) for electrostatically charging the sprayed coating material, wherein the external charging ring (9) is interchangeably mounted on the outside of the atomizer housing (4), and d) a tube shield (11) on the external charging ring (9), dl) wherein the tube shield (11) at least partially encloses the tube (5) of the atomizer housing (4) in a ring shape and thereby protects it from contamination by the sprayed coating material, d2) while the tube shield (11) encloses on its inner side an annular contact area (13) with the tube (5) and / or the steering air ring (6), characterized by e) a blow-out device (14, 15) for blowing out the annular contact area (13) on the inside of the tube shield (11) with air, in particular after cleaning the rotary atomizer (1) in an atomizer cleaning device.

2. Rotary atomizer (1) according to claim 1, characterized in that, a) that the blow-out device (14, 15) has several blow-out nozzles (15) to blow out air, b) that the discharge nozzles (15) are preferably arranged in a ring-shaped distribution with respect to the axis of rotation of the rotary atomizer (1), in particular equidistantly, c) that the number of discharge nozzles (15) is preferably greater than 10, 20, 50 or 100.

3. Rotary atomizer (1) according to claim 2, characterized in that a) that the discharge nozzles (15) are supplied with the air to be discharged from several discharge channels (14), b) that each of the discharge nozzles (15) is preferably supplied with the air to be discharged from one of the discharge channels (14), c) that the discharge nozzles (15) preferably open at the distal end of the tube shield (11), d) that the exhaust channels (15) are preferably grooves (15) in the inner wall of the tube shield (11), e) that the tube shielding (11) between the grooves (15) preferably rests on the outside of the tube (5) or the steering air ring (6), so that the grooves (15) are bounded on the outside by the inside of the tube shielding (11) and on the inside by the outside of the tube (5) or the steering air ring (6).

4. Rotary atomizer (1) according to claim 3, characterized in that a) that the individual discharge nozzles (15) each have a single nozzle cross-section, wherein the discharge nozzles (15) have a maximum of three different nozzle cross-sections, b) that the discharge nozzles (15) all together have a common discharge cross-section as the sum of the individual nozzle cross-sections, c) that the common discharge cross-section is larger than 0.5 mm 2 , 1 mm 2 , 2 mm 2 , 5 mm 2 , 10 mm 2 , 20 mm 2 , in order to achieve a sufficiently large airflow when blowing out, and / or d) that the individual nozzle cross-sections are each smaller than 1 mm 2 , 0.5 mm 2 , 0.2 mm 2 , 0.1 mm 2 , 0.05 mm 2 , to prevent sprayed coating material from entering the blow-off device (14, 15).

5. Rotary atomizer (1) according to any one of the preceding claims, characterized by a) that the tube shield (11) has a seal (12) at its distal end to seal the annular contact area (13) between the tube shield (11) and the tube (5) of the rotary atomizer (1), and / or b) that the seal (12) has a sealing ring (12), and / or c) that the tube shielding (11) consists of an electrically insulating material, in particular polytetrafluoroethylene, and / or d) that the tube shielding (11) dl) extends distally along the axis of rotation (3) of the rotary atomizer (1) beyond the external charging electrodes (10) of the external charging ring (9), and / or d2) has a length of at least 2 cm, 4 cm, 6 cm, 8 cm or at least 10 cm along the axis of rotation (3) of the rotary atomizer (1), and / or d3) covers at least 10%, 20%, 30% or 50% of the outer surface area of ​​the tube (5).

6. Rotary atomizer (1) according to any one of the preceding claims, characterized by a) that the tube shield (11) is integrally formed on the external charging ring (9) and is made of the same material as the external charging ring (9), or b) that the tube shield (11) is a separate component that is attached to the external charging ring (9) and is optionally made of a different material than the external charging ring (9).

7. Cleaning method for cleaning a rotary atomizer (1) in an atomizer cleaning device, in particular for cleaning a rotary atomizer (1) according to one of the preceding claims, comprising the following steps (S1-S7): a) Inserting the rotary atomizer (1) into the atomizer cleaning device using a coating robot, wherein the rotary atomizer (1) has an atomizer housing (4) with a tube (5) and a tube shield (11), wherein the tube shield (11) encloses on its inside an annular contact area (13) with the tube (5) and / or a steering air ring, b) Cleaning of the rotary atomizer (1) in the atomizer cleaning device, in particular with the following cleaning steps: b) Spraying the atomizer housing (4) from the outside with a cleaning agent, b2) Rinsing coating agent residues from the rotary atomizer (1) into the atomizer cleaning device, and / or b3) Blowing out coating agent residues and rinsing agent residues from the rotary atomizer (1) into the atomizer cleaning device, and c) Extracting the rotary atomizer (1) from the atomizer cleaning device using the coating robot, characterized by the following step after cleaning the rotary atomizer (1) in the atomizer cleaning device: d) Blowing out the annular contact area (13) on the inside of the tube shield (11) with air.

8. Cleaning method according to claim 7, characterized in that the blowing out of the annular contact area (13) of the rotary atomizer (1) takes place while the rotary atomizer (1) is being led out of the atomizer cleaning device by the coating robot.

9. Cleaning method according to claim 8, characterized in that, a) that the rotary atomizer (1) is stopped at a holding point by the coating robot when being led out of the atomizer cleaning device, in particular for a holding time of 10s, 2s-5s or 3s, and b) that the rotary atomizer (1) is dried at the holding point by blowing on it with drying air from the outside, in particular at the annular contact area (13) on the inside of the tube shield (11) 10. Cleaning method according to one of claims 7 to 9, characterized in that the rotary atomizer (1) is blown with drying air during its removal from the atomizer cleaning device in order to dry the rotary atomizer (1) on the outside.

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