Atomizer and related operation method

Abstract

The present invention relates to an atomizer (1) for applying multi-component paint, comprising a raw paint connection (4), a hardener connection (7), a mixer (11), a hardener line (12) leading from the hardener connection (7) to the mixer (11) within the atomizer (1), a raw paint line (10) leading from the raw paint connection (4) to the mixer (11) within the atomizer (1), and a main valve (HN1) for controlling the paint feed, which is arranged downstream of the mixer (11) and controls the flow rate of the multi-component paint to the application element (3), in particular to the rotatable bell cup (3). The atomizer (1) according to the invention is characterized by a first return connection (22) for returning the multi-component paint from the atomizer (1) to the return system. To this end, the atomizer (1) has a first return line (23) which branches in the atomizer (1) between the mixer (11) and the main valve (HN1) and opens into a first return connection (22). Furthermore, the invention also includes a corresponding operating method.

Description

[Technical Field]

[0001] The present invention relates to an atomizer (eg, a rotary atomizer) for applying multi-component paints and an associated method of operation. [Background technology]

[0002] Modern paint shops for painting automotive body parts typically use rotary atomizers as application devices, which, depending on their design, are capable of applying multi-component paints, which are made by mixing base paints and hardeners in the rotary atomizer. Such paint shops are known, for example, from US Pat. No. 5,649,393.

[0003] The problem here is the buildup of paint residues, which occurs, for example, during color changes.

[0004] One solution to this problem is the use of so-called wet dust collection systems, in which the multi-component reactive coating material introduced into the wet dust collection system is filtered from the water by suitable chemicals (e.g. flocculation, flotation) and the filter cake then has to be disposed of as hazardous waste, which is very costly.

[0005] Another option is to use a so-called dry dust collection system. In this case, the multi-component reactive coating material must not be directly released into the coating booth. For this purpose, currently, separate facilities such as a solvent-flushed dust collection hopper or dust collection container equipped with a filter mat are required, which require a lot of maintenance and cleaning.

[0006] All currently available solutions introduce, among other things, volatile organic compounds (VOCs) into the paint booth, which may have to be removed from the exhaust air in further treatment steps.

[0007] In the case of a color change with associated flushing and pumping processes, the rotary atomizer is, for example, positioned above a dust collection hopper or dust bin that is flushed, so that paint residues of multi-component paints can be flushed from the rotary atomizer into the dust collection hopper or dust bin. However, this requires the rotary atomizer to be moved to the dust collection hopper, which takes additional time and results in a significant loss of cycle time, i.e., the time required for the paint change extends the required cycle time of the painting facility.

[0008] Another drawback of flushing multi-component paint into a dust collection hopper or dust collection container is that it is not possible to clean the atomizer's exterior surface in parallel during a paint change. As a result, these processing steps must be performed one by one, which in turn requires additional time. For example, the rotary atomizer can first be moved into a dust collection hopper or dust collection container to flush out paint residues from the multi-component paint. The rotary atomizer can then be moved into a cleaning device to clean the exterior of the rotary atomizer.

[0009] Furthermore, US Pat. No. 5,629,999 discloses a painting installation for applying single-component paints, which essentially allows for the recirculation of paint foam during color changes by means of a media-operated return valve. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] German Patent Application Publication No. 102015010158 [Patent Document 2] German Patent Application Publication No. 102009020064 Summary of the Invention [Problem to be solved by the invention]

[0011] In view of the above, the present invention is based on the problem of providing a correspondingly improved atomizer and a corresponding method of operation. [Means for solving the problem]

[0012] This problem is solved by an atomizer according to the invention as defined in claim 1 or by a corresponding operating method as defined in the dependent claims.

[0013] The present invention includes the overall technical teaching of flushing multi-component paint residues from a rotary atomizer into a separate return, rather than in the direction of an application element (e.g., a bell cup). This offers the advantage that two processing steps, specifically flushing multi-component paint residues from the atomizer on the one hand and cleaning the atomizer's exterior on the other hand, can be carried out simultaneously during a color change. This allows for a shorter cycle time for a paint facility, i.e., an increased operating speed.

[0014] The atomizer according to the invention has many similarities to known atomizers known from the prior art.

[0015] Thus, the atomizer according to the present invention also has a base paint connection for supplying base paint and a hardener connection for supplying hardener.

[0016] The atomizer according to the invention also comprises a mixer for mixing the base paint with the curing agent to form the multi-component paint, which is usually designed as a static mixer (e.g., grid mixer, spiral mixer).

[0017] A hardener line extends from the hardener connection to the mixer within the atomizer, and a raw paint line extends from the raw paint connection to the mixer within the atomizer.

[0018] Furthermore, the atomizer includes a main valve, known per se, for controlling the paint feed, which is arranged downstream of the mixer and controls the flow rate of the multi-component paint to the application element (e.g., a bell cup).

[0019] The atomizer of the present invention receives the curing agent and base paint at the inlet side, mixes these paint components in a mixer to form a multi-component paint, and then delivers the multi-component paint to the part to be coated via an application element (e.g., a bell cup).

[0020] The atomizer according to the invention is characterized by a first return connection for returning the multi-component paint from the atomizer to the return system, which occurs, for example, during a paint change, as will be described in more detail below. A first return line extends within the atomizer, which branches within the atomizer between the mixer and the main valve and opens into the first return connection. During a color change, the main valve is usually closed to prevent further ejection of multi-component paint from the application element. Residues of the multi-component paint still present in the atomizer can then be fed via the first return line to the first return connection, which is usually connected to the return system.

[0021] It should be mentioned here that the atomizer may have multiple main needle valves and multiple two-component return systems.

[0022] It should be mentioned that in general, the atomizer according to the invention is preferably a rotary atomizer with a bell cup as application element, which is well known per se from the prior art, but in principle the invention may also be implemented with other types of atomizers, such as air atomizers.

[0023] In a preferred embodiment of the present invention, a first controllable return valve located downstream and a second controllable return valve located upstream, which are preferably independently controllable, are arranged in series in the first return line in the atomizer, which provides the possibility that flushing medium is trapped between the two return valves in the first return line to prevent or reduce to an acceptable level any reaction between different mixed paint systems.

[0024] The atomizer according to the present invention also preferably has a first flushing connection for supplying a diluent (flushing agent) and / or pulsed air. In practice, pulsed air blasts and diluent are supplied alternately to achieve the best possible flushing effect. A first flushing line extends within the atomizer, starting from the first flushing connection and opening into a first return line downstream of the downstream first return valve. This return line provided according to the present invention can then be flushed via this first flushing connection and the first flushing line starting from it. For this purpose, a first flushing valve is preferably arranged in the first flushing line to control the inflow of diluent or pulsed air from the first flushing connection to the first return line.

[0025] Furthermore, the atomizer according to the present invention preferably comprises at least one controllable hardener valve disposed in the hardener line for controlling the inflow of the hardener. Similarly, there is preferably at least one controllable base paint valve disposed in the base paint line for controlling the inflow of the base paint.

[0026] The atomizer according to the present invention also preferably has a second return connection for returning the raw paint independently of the curing agent before mixing with the curing agent. A second return line extends within the atomizer, branches off from the raw paint line upstream of the raw paint valve, and opens into the second return connection. A controllable third return valve is preferably disposed in this second return line, which controls the recirculation of the raw paint through the second return connection. During the recirculation of the raw paint, the raw paint valve is normally closed, while the third return valve is open, so that the raw paint supplied to the inlet side is returned to the second return line.

[0027] Furthermore, the atomizer according to the present invention preferably has a second flushing line, which starts from the second flushing connection or the first flushing connection and opens into the raw paint line downstream of the raw paint valve. Preferably, a second flushing valve is provided, which is arranged in the second flushing line and controls the flow of flushing agent into the raw paint line. Also, a third flushing line is preferably provided, which starts from the third flushing connection or the first flushing connection or the second flushing connection and opens into the hardener line downstream of the hardener valve. Preferably, a third flushing valve is arranged in this third flushing line and controls the flow of flushing agent into the hardener line.

[0028] And, in the atomizer according to the invention, the hardener line and the base paint line can be flushed, preferably independently of each other, with the flushing agent supply both controlled by a flushing valve.

[0029] The atomizer according to the invention may also have a short flushing line leading to the application element downstream of the main valve and starting from the first flushing connection or the second flushing connection or the third flushing connection or a further fourth flushing connection, in which short flushing line there is preferably a controllable short flushing valve controlling the flow rate of the flushing agent through the short flushing line.

[0030] It should further be mentioned that the atomizer according to the present invention preferably includes a paint tube containing a mixer and an upstream second return valve. Here, it should be mentioned that the paint tube also preferably includes a main valve that may be designed as a main needle valve and has a displaceable valve needle. Here, the valve needle of the main needle valve is designed as a static mixer (e.g., grid mixer, spiral mixer), i.e., the valve needle here can fulfill two functions. On the one hand, the valve needle serves as a valve element for controlling the material flow. On the other hand, the valve needle also forms a static mixer.

[0031] In a preferred embodiment, the upstream second return valve is designed as a diaphragm needle valve. This means that the diaphragm needle valve has a valve seat and a displaceable valve needle that opens or closes the valve seat depending on its position. Furthermore, such a diaphragm needle valve is characterized by a valve diaphragm that annularly surrounds the valve needle and serves to drive and / or seal the valve needle. Such diaphragm needle valves are known, for example, from WO 2009 / 019036, the contents of which are hereby incorporated by reference into the present disclosure with respect to the design, structure, and operation of the diaphragm needle valve.

[0032] The valve seat of the second return valve may be made of iron, while the valve needle of the second return valve may pass through a plastic sealing disk or may be made of titanium, for example. Furthermore, the mixer may open on the outlet side into a distributor, which receives the mixed multi-component paint and is at least partially made of metal.

[0033] As already mentioned above, diaphragm needle valves are intended in the context of the present invention. In a preferred embodiment, the main valve, the first return valve, the second return valve, the hardener valve and / or the base paint valve are also designed as such diaphragm needle valves.

[0034] It should further be mentioned that the present invention does not only claim the atomizer according to the invention as broadly described above, but rather also claims a corresponding method of operation for such an atomizer, in which a base coating material and a hardener are fed and mixed in the atomizer to form a multi-component coating material which is then finally applied, for example via a rotating bell cup.

[0035] The operating method according to the invention is characterized in that the multi-component paint is returned during a color change via a first return line branching between the mixer and the main valve, so that, in contrast to known rotary atomizers, residues of the multi-component paint are not released via the application element.

[0036] Preferably, the main valve (eg, main needle valve) of the atomizer (eg, rotary atomizer) is closed during recirculation of the multi-component paint.

[0037] Then, for a color change, the following steps are preferably performed in this order to pump new paint into the atomizer: -Main valve closing process. Opening the first return valve and the second return valve. · The process of opening the raw paint valve to fill the raw paint line with raw paint. Opening the hardener valve to fill the hardener line with hardener. Returning the old multi-component paint and a portion of the remaining flushing agent and the new multi-component paint through the first return line to the first return line. Closing the raw paint valve, hardener valve, first return valve, and second return valve in this order. This valve closing sequence ensures that the paint medium / solvent mixture in the first return line is hermetically sealed, thus preventing reaction with atmospheric moisture.

[0038] In a method of operation according to the present invention, the following steps are preferably carried out to flush the atomizer during a color change. The second flushing valve is opened to flush the raw paint line. Open the third flushing valve and flush the hardener line. Opening the first return valve and the second return valve to flush the old multi-component paint and flushing agent out through the first return line. Filling the raw paint line, hardener line and first return line with flushing agent. Closing the first return valve and the second return valve when the first return line is filled with flushing agent.

[0039] To flush the first return line during application of the multi-component paint, the first flushing valve is then preferably closed and a flushing agent is introduced into the first return line. Preferably, solvent and pulsed air are supplied alternately to achieve a good cleaning effect. Then, at the end of the flushing process, solvent is preferably supplied to partially fill the first return line with flushing agent.

[0040] The atomizer design of the present invention allows the following steps to be performed simultaneously or at least overlapping in time: · The process of externally cleaning the atomizer, especially by spraying the atomizer with a solvent. · Changing color in the atomizer, particularly involving flushing the atomizer out into the first return line and pumping new base paint and new hardener into the atomizer. [Effects of the Invention]

[0041] The present invention provides several advantages which can be summarized as follows: • No material is released through the paint nozzle during color changes. As a result, external cleaning of the atomizer can be carried out in parallel with the paint change. This means that paint changes can be carried out within the normal 15 second cycle gap without any loss of cycle time, thereby increasing the capacity of the paint shop. Cost savings due to the elimination of receiving hoppers or dust collection bins, and the associated elimination of time-consuming cleaning and maintenance of such facilities. • Significant reduction in complexity due to elimination of the following steps or concepts: Positioning of receiving hoppers or dust collection containers within the paint room. Motion travel (programming teaching programs). Safety concept (software protection for disconnecting high voltage). As a result of the present invention and the elimination of the flushed receiving hopper, significantly less VOCs are introduced into the booth, saving solvents, which may mean the elimination or reduction of exhaust gas purification, if required. • When wet dust collection is used, chemical use can be significantly reduced. Through the new return system, the collected multi-component reactive coating and solvent mixtures can be collected in a central location and returned to the manufacturer for recycling, which not only protects the environment but also reduces costs. [Brief explanation of the drawings]

[0042] Other advantageous further embodiments are set forth in the dependent claims or are explained in more detail below in conjunction with the description of preferred embodiments of the invention with reference to the drawings.

[0043] [Figure 1] 1 is a schematic diagram of a rotary atomizer according to the present invention on the arm of a painting robot. [Figure 2A] 1 is a cross-sectional view of a main needle valve according to the present invention with a built-in return system. FIG. [Figure 2B] Figure 2A main needle valve with open return system. [Figure 3A] 4 is a flowchart showing an operation procedure according to the present invention. [Figure 3B] 4 is a flowchart showing an operation procedure according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0044] 1 shows a schematic diagram of a rotary atomizer 1 according to the present invention, which is mounted on a robot arm 2 of a conventional painting robot with a serial robot mechanism. The robot arm 2 is the distal robot arm of the painting robot, which is also referred to as "arm 2" according to conventional technical terminology.

[0045] The rotary atomizer 1 is used to apply multi-component paints via a rotating bell cup 3, as known from the prior art.

[0046] For the supply of raw paint, the rotary atomizer 1 has a raw paint connection 4 to which the desired raw paint is supplied by a color changer 5 in the robot arm 2 .

[0047] A metering pump 6 is arranged between the raw paint connection 4 of the rotary atomizer 1 and the color changer 5, which delivers the raw paint at a desired paint flow rate. The metering pump 6 can be bypassed by a bypass valve By1 connected in parallel.

[0048] The rotary atomizer 1 also has a hardener connection 7 for supplying hardener, which is supplied via a metering pump 9 by a valve unit 8 comprising a hardener valve H1 and a diluent valve VH.

[0049] Within the rotary atomizer 1, the raw paint line 10 starts from the raw paint connection 4 and opens via the raw paint valve SL1 into a static mixer 11, which in a preferred embodiment is designed as a spiral mixer, as shown in Figures 2A and 2B.

[0050] Similarly, a hardener line 12, in which a hardener valve H1 is arranged to control the inflow of hardener, starts from the hardener connection 7. The hardener line 12 also opens into a mixer 11, which mixes the raw paint with the hardener.

[0051] A main needle valve HN1 is located downstream of the mixer 11 to control the flow rate of the multi-component paint from the mixer 11 to the bell cup 3. The structure and operation of the main needle valve HN1 is shown in Figures 2A and 2B and will be described separately.

[0052] The rotary atomizer 1 also has a return connection 13 for returning the raw paint to a return system (not shown). For this purpose, a return line 14 extends inside the rotary atomizer 1, which branches from the raw paint line 10 between the raw paint connection 4 and the raw paint valve SL1 and opens into the return connection 13. A return valve RF1 / SL1 is located in this return line 14 and controls the flow rate to the return system.

[0053] Furthermore, the rotary atomizer has a flushing connection 15 for flushing the raw paint line 10. A flushing line 16 starts from the flushing connection 15 and opens into the raw paint line 10 downstream of the raw paint valve SL1. A flushing valve V / PL is located in the flushing line 16 for flushing the raw paint line 10.

[0054] A valve unit 17 with a diluent valve V and a pulse air valve PL is located in the robot arm 2 of the painting robot, where the valve unit 17 may optionally supply diluent (flushing agent) or pulse air to the flushing connection 15.

[0055] Furthermore, the rotary atomizer 1 includes a flushing connection 18 for flushing the hardener line 12. A flushing line 19 starts from the flushing connection 18 and opens into the hardener line 12, and a flushing valve V / H1 is arranged in the flushing line 19.

[0056] Furthermore, the rotary atomizer 1 has short-time flushing connections 20, 21 for short-time flushing of the rotary atomizer 1, which are known per se from the prior art and will not be described in detail. It should only be mentioned that the rotary atomizer 1 contains short-time flushing valves KSL, KS for short-time flushing.

[0057] Here, the rotary atomizer 1 features a return connection 22 that allows the multi-component paint to be returned to a return system, not shown. For this purpose, a return line 23 branches in the rotary atomizer 1 between the mixer 11 and the main needle valve HN1 and opens into the return connection 22. Two return valves RF4, RF41 are located in turn in the return line 23, where the upstream return valve RF4 is also shown in Figures 2A and 2B and will therefore be described separately.

[0058] For flushing the return line 23, the rotary atomizer 1 further comprises a flushing connection 24 to which diluent or pulsed air can be supplied by means of the valve unit 17. In the rotary atomizer 1, a flushing line 25 starts from the flushing connection 24, which opens into the return line 23 via the flushing valve V2 / PL2, allowing flushing of the return line.

[0059] The valves in the robot arm 2 and rotary atomizer 1 are partly designed as conventional needle valves without separating diaphragms, which can be seen from the corresponding hatching as in the drawing legend, but partly as needle valves with separating diaphragms, known per se from WO 2009 / 019036.

[0060] 2A and 2B are described below, which illustrate the design and operation of main needle valve HN1, mixer 11, and return valve RF4. Figure 2A shows both main needle valve HN1 and return valve RF4 closed. In the illustration shown in Figure 2B, main needle valve HN1 is also closed, but return valve RF4 is open.

[0061] Here, these figures show the paint tube 26 housing the main needle valve HN1, the mixer 11 and the return valve RF4, which now also continues into the bell cup 3, which is known per se from the prior art.

[0062] The needle seat 27 is connected to the paint tube 26 , and a sealing disk 28 made of POM (polyoxymethylene) is arranged between the paint tube 26 and the needle seat 27 .

[0063] Finally, a distributor 29 is located behind the needle seat 27, also made of POM, and contains a paint line 30 leading to the pel cup 3.

[0064] The paint tube 26 , sealing disc 28 and needle seat 27 contain an axially continuous bore 31 which opens into a paint line 30 .

[0065] The valve needle 32 is displaceable in the direction of the double arrow within the bore 31 and has two functions.

[0066] Firstly, the valve needle 32 is designed as a spiral mixer, thus forming a mixer 11 for mixing the base paint and the hardener.

[0067] The valve needle 32, in turn, conventionally acts as a valve element to control the flow of paint to the paint line 30. To this end, the valve needle 32 has a valve head 33 that opens or closes a corresponding valve seat.

[0068] The return valve RF4 is arranged in a further axial bore 34 and has a valve needle 35 displaceable in the direction of the double arrow within the bore 34. The valve needle 35 of the return valve RF4 also has a valve head 36 which closes (as shown in Figure 2A) or opens (as shown in Figure 2B) a valve seat.

[0069] Additionally, Figures 2A and 2B show a line portion of return line 23 that is selectively opened or closed by return valve RF4.

[0070] In the following, the flow charts of Figures 3A and 3B are described, which illustrate the method of operation according to the present invention.

[0071] In the first step S1, the initial state is first shown.

[0072] In this initial state, the main channel is filled with flushing medium, while the return line 23 between the return valves RF4, RF41 is filled with flushing medium. In this initial state, the return valves RF4, RF41, and RF1 / SL1 are closed. The main needle valve HN1, the base paint valve SL1, and the hardener valve H1 are also closed, as are the flushing valves V / PL, V / H1, and V2 / PL2.

[0073] Here, step S2 shows the pumping of fresh paint into the rotary atomizer 1.

[0074] The main channel is filled with new paint. During this process, the return valves RF4 and RF41 are opened, while the return valve RF1 / SL1 and the main needle valve HN1 are closed. Meanwhile, the raw paint valve SL1 and the hardener valve H1 are opened, while the flushing valves V / PL, V / H1, and V2 / PL2 are closed.

[0075] At the end of this pumping, the base paint valve SL1 and the hardener valve H1 are then closed first. Next, the return valve RF41 is closed. Then, finally, the return valve RF4 is closed. This sequence of closing the valves during pumping ensures that the paint medium / solvent mixture is hermetically sealed in the atomizer return system, and therefore prevents reaction with atmospheric moisture.

[0076] In step S3, painting with new paint is then performed. During this process, the return valves RF4, RF41, and RF1 / SL1 are closed, while the main needle valve HN1, raw paint valve SL1, and hardener valve H1 are opened. The flushing valves V / PL, V / H1, and V2 / PL2 are also closed during this process. At the end of the painting process, the main needle valve HN1, hardener valve H1, and raw paint valve SL1 are closed.

[0077] In the next step S4, flushing of the rotary atomizer 1 is then carried out after the coating process is completed. In this process, the return valves RF4 and RF41 are opened, while the return valve RF1 / SL1, main needle valve HN1, raw paint valve SL1, and hardener valve H1 are closed, and the flushing valves V / PL and V / H1 are opened.

[0078] In the next step S5, filling with flushing agent is then performed, whereby the main channel and the flushing line 23 between the flushing valves RF4 and RF41 are filled with flushing agent, where the valve positions of the various valves are shown in step S5.

[0079] Finally, in step S6, flushing of the return system is performed according to the present invention, so that the return line 23 can be flushed during the above-mentioned painting process. During this process, the main needle valve HN1, the raw paint valve SL1, and the hardener valve H1 are opened to allow paint in. Meanwhile, the flushing valves V / PL and V / H1 are closed, as are the return valves RF4 and RF41. Furthermore, the flushing valve V2 / PL2 is opened and then closed again at the end of the flushing process.

[0080] The present invention is not limited to the preferred embodiment described above. Rather, numerous variations and modifications are possible using the concept of the present invention, which fall within the scope of the present invention. In particular, the present invention claims the subject matter and features of the dependent claims independently of the claims to which they refer, and in particular without the features of the main claim. Thus, the present invention includes various inventive aspects which enjoy protection independently of each other.

[0081] [Note] [Appendix 1] An atomizer (1), in particular a rotary atomizer, for applying multi-component paints, comprising: a) at least one raw material connection (4) for supplying raw material; b) at least one hardener connection (7) for supplying hardener; c) at least one mixer (11) for mixing said base paint with said curing agent to form said multi-component paint; d) at least one hardener line (12) leading from the hardener connection (7) to the mixer (11) within the atomizer (1); e) at least one raw paint line (10) leading from the raw paint connection (4) to the mixer (11) within the atomizer (1); f) at least one main valve (HN1) for controlling the paint feed, said main valve (HN1) being arranged downstream of said mixer (11) and controlling the flow rate of said multi-component paint to the application element (3), in particular to the rotatable bell cup (3); and g) a first return connection (22) for returning the multi-component paint from the atomizer (1) to a return system; and h) a first return line (23) branching in the atomizer (1) between the mixer (11) and the main valve (HN1) and opening into the first return connection (22); An atomizer (1) characterized by having:

[0082] [Appendix 2] a downstream controllable first return valve (RF41) and an upstream controllable second return valve (RF4) are arranged in series in the first return line (23); An atomizer (1) as described in Appendix 1.

[0083] [Appendix 3] a) a first flushing connection (24) for supplying diluent and / or pulsed air; b) a first flushing line (25) starting from the first flushing connection (24) and opening into the first return line (23) downstream of the first return valve (RF41); c) a first flushing valve (V2 / PL2) arranged in the first flushing line (25) and controlling the inflow of the diluent and / or the pulsed air from the first flushing connection (24) to the first return line (23); having An atomizer (1) as described in Appendix 2.

[0084] [Appendix 4] a) at least one controllable hardener valve (H1) disposed in the hardener line (12) and controlling the inflow of the hardener; and b) at least one controllable raw paint valve (SL1) arranged in said raw paint line (10) and controlling the inflow of said raw paint; having An atomizer (1) according to any one of appendices 1 to 3.

[0085] [Appendix 5] a) a second return connection (13) for returning said raw paint; b) a second return line (13) branching off from the raw paint line (10) upstream of the raw paint valve (SL1) and opening into the second return connection (13); c) a controllable third return valve (RF1 / SL1) arranged in said second return line (13) and controlling the return flow rate through said second return connection (13); having An atomizer (1) according to any one of appendices 1 to 4.

[0086] [Appendix 6] a) a second flushing connection (15) or a second flushing line (16) starting from the first flushing connection and opening into the raw paint line (10) downstream of the raw paint valve (SL1), b) a second flushing valve (V / PL) disposed in the second flushing line (16) and controlling the inflow of flushing agent into the raw paint line (10); c) a third flushing connection (18) or a third flushing line (19) starting from the first flushing connection or the second flushing connection and opening into the hardener line (12) downstream of the hardener valve (H1); d) a third flushing valve (V / H1) disposed in the third flushing line (19) and controlling the inflow of flushing agent into the hardener line (12); having An atomizer (1) according to any one of appendices 1 to 5.

[0087] [Appendix 7] a) a short-time flushing line leading to the application element (3) downstream of the main valve (HN1) and starting from the first flushing connection or the second flushing connection or the third flushing connection (20) or the fourth flushing connection (21); b) a controllable short-time flushing valve (KS, KSL) disposed in the short-time flushing line and controlling the flow rate of the flushing agent through the short-time flushing line; having An atomizer (1) according to any one of appendices 1 to 6.

[0088] [Appendix 8] a paint tube (26) including the mixer (11) and the second return valve (RF4) upstream thereof; An atomizer (1) according to any one of appendices 1 to 7.

[0089] [Appendix 9] a) The second return valve (RF4) a1) Valve seats, a2) a displaceable valve needle (35) that opens or closes the valve seat depending on its position; a3) a valve diaphragm annularly surrounding the valve needle and serving to drive and / or seal the valve needle; The valve is designed as a diaphragm needle valve having b) the valve seat of the second return valve (RF4) is preferably made of iron; c) the valve needle (35) of the second return valve (RF4) preferably passes through a plastic sealing disc (28); d) the valve needle (35) of the second return valve (RF4) is preferably made of titanium; e) the mixer (11) preferably opens at the outlet side into a distributor (29) which receives the mixed multi-component paint and is at least partly made of metal; An atomizer (1) according to any one of appendices 1 to 8.

[0090] [Appendix 10] a) the main valve (HN1); b) the first return valve (RF41); c) said second return valve (RF4); d) the hardener valve (H1), and / or e) the raw paint valve (SL1); However, it is designed as a diaphragm needle valve, each having a valve seat, a displaceable valve needle that opens or closes the valve seat depending on its position, and a valve diaphragm that annularly surrounds the valve needle and serves to drive and / or seal the valve needle; An atomizer (1) according to any one of appendices 1 to 9.

[0091] [Appendix 11] A method of operating the atomizer (1) according to any one of claims 1 to 10, comprising: a) supplying at least one base paint to said atomizer (1) at said base paint connection (4) of said atomizer (1), b) passing the raw paint through the raw paint line (10) in the atomizer (1) to the mixer (11); c) supplying at least one hardener to said atomizer (1) at said hardener connection (7) of said atomizer (1); d) passing the curing agent through the curing agent line (12) in the atomizer (1) to the mixer (11); e) mixing the base paint with the curing agent by the mixer (11) to form the multi-component paint; f) controlling the paint feed from the mixer (11) to the application element (3) by the main valve (HN1); and g) applying the multi-component paint by means of the application element (3); h) returning the multi-component paint during a color change through the first return line (23) branching between the mixer (11) and the main valve (HN1); Including, how to drive.

[0092] [Appendix 12] The main valve (HN1) is closed during the return of the multi-component paint. The operating method described in Appendix 11.

[0093] [Appendix 13] In order to pump new paint into the atomizer (1) during color change, a) closing the main valve (HN1); b) opening the first return valve (RF41) and the second return valve (RF4); c) opening the raw paint valve (SL1) to fill the raw paint line (10) with the raw paint; d) opening the hardener valve (H1) to fill the hardener line (12) with the hardener; e) returning the old multi-component paint and a portion of the remaining flushing agent and the new multi-component paint to the first return system through the first return line (23); and f) closing the base paint valve (SL1), the hardener valve (H1), the first return valve (RF41), and the second return valve (RF4) in this order; Including, 13. The method of operation described in Appendix 11 or 12.

[0094] [Appendix 14] In order to flush the atomizer (1) during color change, a) opening the second flushing valve (V / PL) and flushing the raw paint line (10); b) opening the third flushing valve (V / H1) and flushing the hardener line (12); c) opening the first return valve (RF41) and the second return valve (RF4) and flushing the old multi-component paint and the flushing agent through the first return line (23) into the first return system; d) filling the raw paint line (10), the hardener line (12) and the first return line (23) with the flushing agent; e) closing the first return valve (RF41) and the second return valve (RF4) when the first return line (23) is filled with the flushing agent; having 14. The method of any one of appendices 11 to 13.

[0095] [Appendix 15] for flushing the first return line (23) during application of the multi-component paint, opening the first flushing valve (V2 / PL2) and introducing a flushing agent into the first return line (23), in particular by alternately introducing a solvent and pulsed air, preferably with a solvent being supplied to partially fill the first return line (23) with the flushing agent at the end of the flushing process; 15. The method of any one of appendices 11 to 14.

[0096] [Appendix 16] a) external cleaning of the atomizer (1), in particular by spraying a solvent onto the atomizer (1); and b) a step of changing color with the atomizer (1), in particular b1) flushing the atomizer (1) into the first return line (23); b2) pumping new base paint and new hardener into the atomizer (1); a process comprising: are performed simultaneously or at least overlapping in time, 16. The method of any one of appendices 11 to 15. [Explanation of symbols]

[0097] 1 rotating atomizer 2 Robot Arm (Arm 2) 3 Bell Cup 4. Original paint connection 5 Color Changer 6. Metering pump for raw paint 7 Hardener connection 8 Valve unit with diluent valve VH and hardener valve H1 for hardener 9. Metering pump for hardener 10. Original paint line 11 Mixer 12 Hardener Line 13 Return connection for raw paint 14 Return line for raw paint 15 Flushing connection for flushing raw paint line 16 Flushing line for flushing the raw paint line 17 Valve unit with thinner valve V and pulse air valve PL for the original paint 18 Flushing connection for flushing the hardener line 19 Flushing line for flushing hardener line 20, 21 Short-time flushing connection 22 Return Connection 23 Return line 24 Flushing Connection 25 Flushing line for flushing the return line 26 paint tubes 27 Needle Seat 28 POM sealing washer 29 POM distributor 30 Paint line to bell cup 31 Valve needle hole 32 Valve needle as a spiral mixer 33 Valve head of valve needle 34 Return valve RF4 hole 35 Return valve RF4 valve needle 36 Return valve RF4 valve head By1 Bypass valve for metering pump H1 Hardener Valve SL1 Original Paint Valve RF1 / SL1 Return valve for raw paint V / PL Flushing valve for flushing raw paint lines V / H1 Flushing valve for flushing the hardener line HN1 Main needle valve RF4, RF41 Return valve in return line V2 / PL2 Flushing valve for flushing the return line KS, KSL Short-time flushing valve

Claims

1. An atomizer (1), in particular a rotary atomizer, for applying multi-component paints, comprising: a) at least one raw paint connection (4) for supplying raw paint; b) at least one hardener connection (7) for supplying hardener; c) at least one mixer (11) for mixing said base paint with said hardener to form said multi-component paint; d) at least one hardener line (12) leading from the hardener connection (7) to the mixer (11) within the atomizer (1); e) at least one raw paint line (10) leading from the raw paint connection (4) to the mixer (11) within the atomizer (1); f) at least one main valve (HN1) for controlling the paint feed, said main valve (HN1) being arranged downstream of said mixer (11) and controlling the flow rate of said multi-component paint to the application element (3), in particular to the rotatable bell cup (3); and g) a first return connection (22) for returning the multi-component paint from the atomizer (1) to a return system; and h) a first return line (23) branching in the atomizer (1) between the mixer (11) and the main valve (HN1) and opening into the first return connection (22); An atomizer (1), characterized in that it comprises:

2. In the first return line (23), a controllable first return valve (RF41) located downstream and a controllable second return valve (RF4) located upstream are arranged in series. Atomizer (1) according to claim 1.

3. a) a first flushing connection (24) for supplying diluent and / or pulsed air; b) a first flushing line (25) starting from said first flushing connection (24) and opening into said first return line (23) downstream of said first return valve (RF41); c) a first flushing valve (V2 / PL2) arranged in the first flushing line (25) and controlling the inflow of the diluent and / or the pulsed air from the first flushing connection (24) to the first return line (23); having Atomizer (1) according to claim 2.

4. a) at least one controllable hardener valve (H1) arranged in the hardener line (12) and controlling the inflow of the hardener; and b) at least one controllable raw paint valve (SL1) arranged in said raw paint line (10) and controlling the inflow of said raw paint; having Atomizer (1) according to any one of claims 1 to 3.

5. a) a second return connection (13) for returning said raw paint; b) a second return line (13) branching off from the raw paint line (10) upstream of the raw paint valve (SL1) and opening into the second return connection (13); c) a controllable third return valve (RF1 / SL1) arranged in said second return line (13) and controlling the return flow rate through said second return connection (13); having An atomizer (1) according to any one of claims 1 to 4.

6. a) a second flushing connection (15) or a second flushing line (16) starting from said first flushing connection and opening into said raw paint line (10) downstream of said raw paint valve (SL1); b) a second flushing valve (V / PL) disposed in the second flushing line (16) and controlling the flow of flushing agent into the raw paint line (10); c) a third flushing connection (18) or a third flushing line (19) starting from the first flushing connection or the second flushing connection and opening into the hardener line (12) downstream of the hardener valve (H1); d) a third flushing valve (V / H1) disposed in the third flushing line (19) and controlling the inflow of flushing agent into the hardener line (12); having Atomizer (1) according to any one of claims 1 to 5.

7. a) a short-time flushing line leading to the application element (3) downstream of the main valve (HN1) and starting from the first flushing connection or the second flushing connection or the third flushing connection (20) or the fourth flushing connection (21); b) a controllable short-time flushing valve (KS, KSL) disposed in the short-time flushing line and controlling the flow rate of the flushing agent through the short-time flushing line; having Atomizer (1) according to any one of claims 1 to 6.

8. a paint tube (26) containing the mixer (11) and the second return valve (RF4) upstream thereof; Atomizer (1) according to any one of claims 1 to 7.

9. a) the second return valve (RF4) a1) valve seats, a2) a displaceable valve needle (35) that opens or closes said valve seat depending on its position; a3) a valve diaphragm annularly surrounding the valve needle and serving to drive and / or seal the valve needle; The valve is designed as a diaphragm needle valve having b) the valve seat of the second return valve (RF4) is preferably made of iron; c) the valve needle (35) of the second return valve (RF4) preferably passes through a plastic sealing disc (28); d) the valve needle (35) of the second return valve (RF4) is preferably made of titanium; e) the mixer (11) preferably opens at the outlet side into a distributor (29) which receives the mixed multi-component paint and is at least partly made of metal; Atomizer (1) according to any one of claims 1 to 8.

10. a) the main valve (HN1); b) the first return valve (RF41); c) the second return valve (RF4); d) the hardener valve (H1), and / or e) the raw paint valve (SL1); However, it is designed as a diaphragm needle valve, each having a valve seat, a displaceable valve needle that opens or closes the valve seat depending on its position, and a valve diaphragm that annularly surrounds the valve needle and serves to drive and / or seal the valve needle; Atomizer (1) according to any one of claims 1 to 9.

11. A method for operating an atomizer (1) according to any one of claims 1 to 10, comprising: a) supplying at least one base paint to said atomizer (1) at said base paint connection (4) of said atomizer (1); b) passing the raw paint through the raw paint line (10) in the atomizer (1) to the mixer (11); c) supplying at least one hardening agent to said atomizer (1) at said hardening agent connection (7) of said atomizer (1); d) passing the curing agent through the curing agent line (12) in the atomizer (1) to the mixer (11); e) mixing the base paint with the curing agent by the mixer (11) to form the multi-component paint; f) controlling the paint feed from the mixer (11) to the application element (3) by the main valve (HN1); and g) applying said multi-component paint by means of said application element (3); h) returning the multi-component paint during color changes through the first return line (23) branching between the mixer (11) and the main valve (HN1); Including, how to drive.

12. The main valve (HN1) is closed during the return of the multi-component paint. The operating method according to claim 11.

13. In order to pump new paint into the atomizer (1) during color change, a) closing the main valve (HN1); b) opening the first return valve (RF41) and the second return valve (RF4); c) opening the raw paint valve (SL1) to fill the raw paint line (10) with the raw paint; d) opening the hardener valve (H1) to fill the hardener line (12) with the hardener; e) returning the old multi-component paint and a portion of the remaining flushing agent and the new multi-component paint to the first return system through the first return line (23); and f) closing the raw paint valve (SL1), the hardener valve (H1), the first return valve (RF41), and the second return valve (RF4) in this order; Including, 13. The operating method according to claim 11 or 12.

14. To flush the atomizer (1) during color change, a) opening the second flushing valve (V / PL) and flushing the raw paint line (10); b) opening the third flushing valve (V / H1) and flushing the hardener line (12); c) opening the first return valve (RF41) and the second return valve (RF4) and flushing the old multi-component paint and the flushing agent through the first return line (23) into the first return system; d) filling the raw paint line (10), the hardener line (12) and the first return line (23) with the flushing agent; e) closing the first return valve (RF41) and the second return valve (RF4) when the first return line (23) is filled with the flushing agent; having 14. The operating method according to any one of claims 11 to 13.

15. for flushing the first return line (23) during application of the multi-component paint, opening the first flushing valve (V2 / PL2) and introducing a flushing agent into the first return line (23), in particular by alternately introducing a solvent and pulsed air, preferably a solvent being supplied to partially fill the first return line (23) with the flushing agent at the end of the flushing process, 15. A method according to any one of claims 11 to 14.

16. a) external cleaning of said atomizer (1), in particular by spraying said atomizer (1) with a solvent; and b) a color change step in said atomizer (1), in particular b1) flushing the atomizer (1) into the first return line (23); b2) pumping fresh base paint and fresh hardener into the atomizer (1); a process comprising: are performed simultaneously or at least overlapping in time, 16. A method according to any one of claims 11 to 15.

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