Powder separator system for a powder coating plant, powder coating plant comprising such a powder separator system, and method of operating such a powder coating plant

Abstract

A powder separator system (1) for a powder coating plant (20) operable electively in a single-colour or in a multicolour operating mode. The powder separator system (1) has a first powder separator (2) for the single-colour operating mode and a second powder separator (3) for the multicolour operating mode of the powder coating plant (20). The first powder separator (2) has a first dirty gas chamber (4) incorporating a first filter medium, and the second powder separator (3) has a second dirty gas chamber (5) incorporating a second filter medium. Assigned to the two powder separators (2, 3) is a common clean gas chamber (8) which is fluidically connected both to the first dirty gas chamber (4) and to the second dirty gas chamber (5), and assigned to the two powder separators (2, 3) is a common suction blower (9) which is preferably fluidically connected to the common clean gas chamber (8) via a clean gas channel.

Description

[0001] POWDER SEPARATOR SYSTEM FOR A POWDER COATING PLANT, POWDER COATING PLANT WITH SUCH A

[0002] Powder separation system and method for operating such a powder coating system

[0003] Description

[0004] The present invention generally relates to the field of powder coating of workpieces. More specifically, the invention relates to a powder coating system that can be operated selectively in a single-color mode or a multi-color mode.

[0005] In coating technology, it is well known to extract air and excess powder from the interior of powder coating booths in which workpieces or objects are coated with powder using a spray device. For this purpose, it is common practice to equip the powder coating booth with an extraction duct arrangement, which, for example, comprises an extraction duct located in the booth substructure, the first end of which is fluidly connected to the interior of the booth via at least one extraction opening.

[0006] Such a powder coating booth is known, for example, from document EP 0 839 583 A2. It is a vertically cylindrical booth with a funnel-shaped booth floor, which has a suction connection for an external suction source in the center of the booth.

[0007] A similar cylindrical powder coating booth is also known from DE 195 00 872 A1. In addition to the booth floor designed as an extraction funnel, this powder coating booth has a groove-like floor edge along the booth wall, through which air and powder particles can also be extracted from the booth separately from the extraction flow of the extraction funnel.

[0008] From the document DE 198 37 877 A1, a vertically cylindrical powder coating booth with a flat floor plate is known. A slot extends diametrically through the floor plate, into which slot powder particles lying on the booth floor can be pushed by a rotating cleaning device. Spray coating powder is usually conveyed pneumatically to spray devices, so-called spray guns, from which it is sprayed pneumatically and with electrostatic assistance onto the objects / workpieces to be coated. A slight negative pressure is usually maintained in the powder coating booths during spray coating operation to prevent powder particles from escaping from the powder coating booth to the outside. The negative pressure usually maintained in the powder coating booths during spray coating operation also serves to remove excess powder, i.e. powder from the object orTo extract powder particles that bounce off the workpiece or are sprayed past it.

[0009] In powder coating booths of this type, excess powder is extracted by suction to prevent high powder concentrations inside the booth, which could potentially lead to powder dust explosions. Furthermore, the extraction of excess powder serves to recover and recycle the powder.

[0010] To recover excess powder, i.e. powder that has been sprayed past the object / workpiece to be coated or that falls off the object / workpiece, it is known to connect a powder separator, for example in the form of a centrifugal separator (cyclone), to the interior of the powder coating booth via an extraction opening. A suction fan, which is connected, for example, to an air outlet of the powder separator, extracts at least a large portion of the excess powder and air from the interior of the powder coating booth through the powder separator. The extracted powder is separated from the suction air in the powder separator and transported to a powder container, from which it can be fed back into a spray device for spray-coating objects in the powder coating booth, together with fresh coating powder.The air, cleaned of the extracted excess powder in the powder separator, is drawn through the suction fan either into the room atmosphere of the powder coating booth or powder separator installation space or to another filter system (post-filter), in which any powder particles still present in the air are separated. In particular, it is known to use a cyclone or cyclone system as a powder separator to separate powder from the extracted air. When using a cyclone system, which is composed, for example, of one or more cyclones, a suction fan draws excess powder and air from the booth interior through the cyclone system, whereby the powder-air flow in the cyclone system is separated into air and powder by cyclone centrifugal forces. The separated powder falls into a collecting container below the cyclone system, while the air purified of powder is usually blown into the outside atmosphere via a post-filter.Cyclone systems typically require such a post-filter because they cannot separate fine powder particles from the airflow as completely as a filter system would. The powder separated by the cyclone system is usually also recycled and reused for spray coating. In contrast, the powder separated by the post-filter is usually treated as waste.

[0011] Powder coating booths that are used for short coating times with a specific powder type or for frequent changes of powder type are often cylindrical in shape, as cylindrical powder coating booths can be cleaned more quickly than powder coating booths with a rectangular booth interior, thus enabling quick color changes.

[0012] The term "color change" used herein refers to the change from one powder type to another, particularly to a different powder color. With a wide color range and short coating periods for the individual powder types, the downtime for cleaning the powder coating booth and the powder separators used when changing from one powder type to another is often not insignificant. As a result, the operation of the powder coating booth becomes costly and inefficient, at least if no main color is used for more than 50% of the powder coating booth's operating time.

[0013] The powder coating system considered here is, in particular, a powder coating system that can be operated either in a single-color mode or in a multi-color mode. In multi-color mode, different powder colors or powder types are sprayed for only a short time. In this multi-color mode of operation of the powder coating system, a cyclone separator and a post-filter are typically used, and the waste powder from the post-filter is conveyed into a waste container. Although the powder separation efficiency of the cyclone separator is usually lower than that of the post-filter, it can be cleaned more quickly than the post-filter.

[0014] In single-color operating mode, the same powder type or powder color is used for a relatively long period of time. In single-color operating mode of the powder coating system, it is thus possible to dispense with the cyclone separator and route the powder-air mixture containing excess powder from the powder coating booth directly to a downstream filter. The powder recovered in the downstream filter can then be reused via a powder recovery line and a screening device, if provided.

[0015] In single-color operation of the powder coating system, the cyclone separator is typically only used in combination with the post-filter when the coating powder is problematic. In this case, only the recovered powder from the cyclone separator is recycled as recovery powder via a powder recovery line and, if necessary, a screening device, while the waste powder from the post-filter is discharged into a waste container as waste.

[0016] The invention is based on the object of optimising and, in particular, simplifying the cleaning of an air-powder mixture discharged from the coating booth for a powder coating system which can be operated optionally in a single-colour operating mode or in a multi-colour operating mode.

[0017] This object is achieved in particular by a powder separator system according to independent claim 1, wherein advantageous developments of the powder separator system according to the invention are specified in dependent claims 2 to 7. The object underlying the invention is further achieved by a powder coating system according to independent claim 8. Advantageous developments of the powder coating system according to the invention are specified in dependent claims 9 to 16.

[0018] Finally, the object underlying the invention is achieved by an operating method according to the independent patent claim 17, wherein advantageous developments of the method according to the invention are specified in claims 18 and 19.

[0019] Accordingly, the invention relates in particular to a powder separator system for a powder coating system which can be operated selectively in a single-color operating mode or in a multi-color operating mode.

[0020] The powder separator system comprises a first powder separator based on filtration technology for the single-color operating mode of the powder coating system and a second powder separator also based on filtration technology for the multi-color operating mode of the powder coating system.

[0021] A "filtration-based powder separator" is a powder separator designed to separate powder particles from a powder-air mixture by filtration using a filter medium. The powder-air mixture can flow through the filter medium, while the powder particles to be separated from the powder-air mixture to be filtered are retained by the filter medium. The permeation of the air through the filter medium is associated with a pressure difference.

[0022] A surface filter is used as the filter medium. It is particularly preferred that the filter medium be designed as a plate and / or cartridge filter.

[0023] In the powder separator system according to the invention, the first powder separator has a first raw gas chamber with a first filter medium accommodated therein, and the second powder separator has a second raw gas chamber with a second filter medium accommodated therein. The first raw gas chamber of the first powder separator is preferably hermetically separated from the second raw gas chamber of the second powder separator.

[0024] The first raw gas chamber of the first powder separator has a first raw gas inlet, via which a powder-air mixture extracted or discharged from a coating booth of the powder coating system can be supplied to the first raw gas chamber as raw gas in the single-color operating mode of the powder coating system.

[0025] In the same way, the second raw gas chamber of the second powder separator has a second raw gas inlet, via which a powder-air mixture which is extracted or discharged from the coating booth of the powder coating system and which may have previously passed through a centrifugal separator can be fed to the second raw gas chamber of the second powder separator in the multi-color operating mode of the powder coating system as raw gas.

[0026] In other words, in the powder separator system according to the invention, a first powder separator is provided which is used in the single-color operating mode of the powder coating system in order to separate the powder particles from the powder-air mixture discharged from the coating booth in this operating mode.

[0027] However, when the powder coating system is operated in multi-color mode, the second powder separator is used to separate the residual powder that may still be present in the powder-air mixture that was removed from the coating booth and then passed through the centrifugal separator.

[0028] The powder separator system according to the invention is characterized in particular in that a common clean gas chamber is assigned to the two powder separators, i.e. the first powder separator for the single-color operating mode of the powder coating system and the second powder separator for the multi-color operating mode of the powder coating system, which is in fluid communication with both the first raw gas chamber and the second raw gas chamber. Furthermore, a common suction fan is assigned to the two powder separators, which is in fluid communication with the common clean gas chamber either directly or via a clean gas duct. In other words, the powder separator system according to the invention is a so-called combination filter, i.e. a single system designed for both the single-color and the multi-color operating mode of the powder coating system.

[0029] Because this combination filter requires only a single suction fan to draw the powder-air stream to be cleaned through the first or second powder separator as needed, the powder separation system can be designed extremely compactly and space-savingly. Furthermore, it eliminates the need for a separate suction fan with the corresponding control device for each powder separator, allowing the powder separation system to be designed more cost-effectively.

[0030] According to preferred implementations of the powder separator system according to the invention, it is provided that the second raw gas inlet of the second powder separator is further configured to supply, as raw gas, a powder-air mixture extracted or discharged from a powder supply chamber of the powder coating system to the second raw gas chamber of the second powder separator, in particular in the single-color operating mode and preferably both in the single-color operating mode and in the multi-color operating mode of the powder coating system.

[0031] Alternatively, it is also conceivable for the second raw gas chamber of the second powder separator to have a third raw gas inlet, via which a powder-air mixture extracted or discharged from a powder supply chamber of the powder coating system can be supplied as raw gas to the second raw gas chamber of the second powder separator, in particular in the single-color operating mode and preferably both in the single-color operating mode and in the multi-color operating mode of the powder coating system.

[0032] With this refinement of the powder separator system according to the invention, the powder separator system thus acquires an additional function, namely to also clean the powder-air mixture extracted or discharged from the powder supply chamber of the powder coating system. A particular advantage of this is that the powder separator system does not require an additional powder separator for this purpose.Alternatively or in addition to the aforementioned embodiment of the powder separator system according to the invention, it is provided that the second raw gas inlet of the second powder separator is further designed, in particular in the multi-color operating mode of the powder coating system and preferably both in the multi-color operating mode and in the single-color operating mode of the powder coating system, to supply a powder-air mixture extracted or discharged from a powder waste container chamber of the powder coating system to the second raw gas chamber of the second powder separator as raw gas.

[0033] Alternatively, the second raw gas chamber can also have a fourth raw gas inlet, via which a powder-air mixture extracted or discharged from a powder waste container chamber of the powder coating system can be fed to the second raw gas chamber of the second powder separator, in particular in the multi-color operating mode of the powder coating system and preferably both in the multi-color operating mode of the powder coating system and in the single-color operating mode of the powder coating system.

[0034] In this embodiment of the powder separator system according to the invention, the powder separator system also performs an additional task, namely to clean the powder-air mixture extracted or discharged from the powder waste container chamber of the powder coating system, without the powder separator system requiring an additional powder separator for this purpose.

[0035] As an alternative to the two previously mentioned embodiments of the powder separator system according to the invention, in which the powder separator system also serves to clean a powder-air mixture extracted or discharged from a powder supply chamber of the powder coating system and / or to clean a powder-air mixture extracted or discharged from a powder waste container chamber of the powder coating system, it is conceivable that the second raw gas chamber has a third raw gas inlet, via which a powder-air mixture extracted or discharged from a powder supply chamber of the powder coating system can be supplied as raw gas to the second raw gas chamber of the second powder separator, in particular in the single-color operating mode of the powder coating system and preferably both in the single-color operating mode and in the multi-color operating mode of the powder coating system.and via which a powder-air mixture extracted or removed from a powder waste container chamber of the powder coating system can be fed to the second raw gas chamber of the second powder separator, particularly in the multi-color operating mode of the powder coating system and preferably both in the multi-color operating mode of the powder coating system and in the single-color operating mode of the powder coating system.

[0036] According to preferred implementations of the powder separator system according to the invention, it is provided that the first powder separator has a first powder collection area which is arranged at least partially or regionally below the first raw gas chamber of the first powder separator and is designed to receive at least a portion of the powder separated from the raw gas supplied to the first raw gas chamber with the aid of the first filter medium.

[0037] In this case, it is advisable for the first powder collection area to have a first powder discharge outlet, via which the powder collected in the first powder collection area can be fed, as required, preferably with the aid of a powder feed pump, to a powder supply chamber of the powder coating system.

[0038] This measure ensures that the coating powder recovered in the single-color mode of the powder coating system with the help of the first powder separator can be fed back into the coating operation, i.e. can be "reused".

[0039] With regard to the powder separated by the second powder separator of the powder separator system from the powder-air mixture supplied to the second powder separator, according to embodiments of the powder separator system according to the invention, the second powder separator has a second powder collection area, which is arranged at least partially or regionally below the second raw gas chamber of the second powder separator and is designed to receive at least a portion of the powder separated by the second filter medium from the raw gas supplied to the second raw gas chamber of the second powder separator. The second powder collection area preferably has a (second) powder discharge outlet, via which the powder collected in the second powder collection area can be fed as waste powder, if required, preferably with the aid of a powder feed pump or by gravity, to a powder waste container chamber of the powder coating system.

[0040] This ensures that the powder separated from the powder-air stream by the second powder separator during multi-color operation of the powder coating system is not returned to the powder supply or powder supply chamber of the powder coating system. The same applies, in a figurative sense, to the powder separated from the powder-air stream by the second powder separator when the powder-air stream was extracted or removed from the powder supply chamber of the powder coating system and / or from the powder waste container chamber of the powder coating system.

[0041] The object underlying the invention is further achieved by a powder coating system for powder coating workpieces. The powder coating system can be operated either in a single-color mode or in a multi-color mode.

[0042] The powder coating system has at least one coating booth or powder coating cabin in which the workpiece can be coated with powder. Furthermore, at least one extraction system is provided, via which a powder-air mixture can be removed and, in particular, extracted from the at least one coating booth, particularly during a coating operation of the powder coating system or, alternatively, during a cleaning operation of the powder coating system.

[0043] The powder coating system according to the invention is characterized in particular in that it further comprises a powder separator system of the aforementioned type according to the invention in order to appropriately clean the powder-air mixture discharged and in particular extracted from the at least one coating booth.

[0044] Preferably, the powder coating system according to the invention further comprises a centrifugal separator which is designed to separate at least a portion of the powder contained in the powder-air mixture discharged and in particular extracted from the at least one coating booth from the powder-air mixture.

[0045] In particular, it is provided in this context that the powder-air mixture discharged and in particular extracted from the at least one coating booth is only fed to the centrifugal separator when the powder coating system is in its multi-color operating mode.

[0046] The term "centrifugal separator" used herein generally refers to a mass force separator for separating powder particles contained in the powder-air mixture discharged and, in particular, extracted from the at least one coating booth. Centrifugal forces generated by generating a vortex flow are used as the separation process.

[0047] According to a preferred implementation of the latter aspect, the centrifugal separator is preferably designed as a cyclone separator, and in particular as a tangential cyclone separator. A tangential cyclone separator essentially consists of four parts: an inlet cylinder, a cone, a particle collection container, and a dip tube mounted centrally from above in the inlet cylinder.

[0048] In the inlet cylinder, the powder-air mixture is blown or sucked in tangentially and guided along a circular path. Due to the tapered shape of the adjacent cone, the rotational speed of the supplied powder-air mixture increases to such an extent that the powder particles are thrown against the cone walls by centrifugal force and decelerated to such an extent that they break free from the flow and trickle down into the collection container. The purified air exits the cone upwards through the central dip tube.

[0049] The guidance of the powder-air mixture can be enhanced by spiral-shaped guide vanes attached to the inner wall of the separator.

[0050] The centrifugal separator used in the powder coating system according to the invention thus has a corresponding inlet area for the powder-air mixture to be treated in the centrifugal separator, wherein the inlet area is preferably part of a tangential inlet cylinder. The powder-air mixture discharged from the at least one coating booth, and in particular extracted by suction, is fed to the cyclone separator via the inlet area. Furthermore, the centrifugal separator has an outlet area, which is preferably part of the dip tube mounted centrally from above into the inlet cylinder. The powder-air mixture pre-cleaned in the centrifugal separator is discharged via the outlet area.

[0051] In this context, it is preferably provided that the outlet area of ​​the centrifugal separator is fluidly connected or connectable to the second raw gas inlet, i.e., to the raw gas inlet of the second powder separator of the powder separator system, via a duct or line system. In this embodiment, the second powder separator of the powder separator system thus serves as a downstream filter for the centrifugal separator.

[0052] In order to ensure that the coating powder separated in the centrifugal separator from the correspondingly supplied powder-air mixture can be disposed of as required or can be fed back into the powder supply of the powder coating system, according to embodiments of the powder coating system according to the invention it is provided that the centrifugal separator has a powder outlet which can be connected as required via a powder line to the powder supply of the powder coating system or to a powder waste container of the powder coating system.

[0053] The powder outlet of the centrifugal separator is located primarily in the lower conical section of the separator's cone. The powder collection container is sometimes also referred to as a "bunker." The bunker can be emptied during operation of the centrifugal separator, with the powder preferably being discharged via a rotary valve to prevent gas exchange with the environment.

[0054] The operation of a rotary valve is based on a rotor with a specific number of rotor blades, which rotates in a precisely fitting housing. Each rotor cell receives powder as the material to be conveyed below the inlet opening, and the powder / material falls out at the outlet. This creates a volumetrically continuous conveying process. The conveying capacity is determined by the contents of the rotor cells and the speed of the rotor. In particular, in the last-mentioned embodiments of the powder coating system according to the invention, it is provided that the powder outlet of the centrifugal separator can also be connected, if required, either (via a powder line) to the powder waste container or (via a corresponding powder line) to a powder supply container of a powder supply system of the powder coating system.

[0055] In other words, the coating powder recovered in the centrifugal separator can either be disposed of (by feeding the coating powder to the powder waste container) or reused in the coating operation of the powder coating plant by feeding the powder separated in the centrifugal separator to the powder supply of the powder coating plant via a powder line with a powder supply container.

[0056] Since the extraction pipe system or extraction channel system can be flow-connected optionally to the first raw gas inlet of the first powder separator of the powder separator system or to the inlet area of ​​the centrifugal separator, it is possible in an easy-to-implement but nevertheless effective manner for the extraction pipe system or extraction channel system to be flow-connected optionally to various powder separators, such as the centrifugal separator or the first powder separator designed as a filter separator.

[0057] In this way, the first powder separator of the powder separator system or the centrifugal separator with the second powder separator of the powder separator system arranged as a downstream filter can be used for powder separation either in the single-color or multi-color coating mode of the powder coating system.In particular, the first powder separator of the powder separator system can be used in coating operation with a first powder type and / or a first powder color during a single-color operating mode of the powder coating system and the centrifugal separator with the second powder separator of the powder separator system serving as a downstream filter can be used in coating operation with a different powder type and / or different powder color, in particular in the multi-color operating mode of the powder coating system, without the need to replace the powder separators or to intensively clean the powder separators, which would be disadvantageous with regard to a quick powder change with only minimal downtimes when changing the powder.

[0058] In this context, it is particularly conceivable for the extraction pipe system or extraction duct system to have a corresponding distributor, via which the extraction pipe system or extraction duct system is divided into two pipe system or duct system sections. A first duct system serves to supply the powder-air mixture to the first raw gas inlet of the first powder separator of the powder separator system, while the other duct section serves to supply the powder-air mixture to the centrifugal separator. The distributor is preferably arranged in the booth substructure of the at least one powder spray coating booth, so that a compact design of the powder coating booth and in particular of the powder coating system can be realized, so that in particular the footprint of the powder coating booth remains unchanged compared to conventional powder coating booths known from the prior art.

[0059] In an easy-to-implement yet effective embodiment of the latter aspect, the distributor, which is arranged in particular in the substructure of the powder coating booth, is designed as a T- or Y-section with one inlet and two outlets. The inlet of the distributor is fluidly connected or connectable to the extraction duct, which serves to extract or discharge the powder-air mixture from the at least one coating booth as needed. The two outlets of the distributor can each be fluidly connected or connectable to a duct section leading out of the booth substructure. One outlet of the distributor is fluidly connected to the first raw gas inlet of the first powder separator of the powder separator system, while the other outlet of the distributor is fluidly connected to the inlet area of ​​the centrifugal separator.

[0060] In this way, it is possible to connect two independently operating powder separator systems to the extraction pipe system or extraction duct system, whereby - depending on the type of powder sprayed in the powder spray coating operation or depending on the respective operating mode of the powder coating system - one of the two powder separators (i.e. either the first powder separator of the powder separator system or the centrifugal separator with the second powder separator serving as a post-filter) is fluidically connected to the extraction pipe system or extraction duct system.

[0061] Alternatively, it is nevertheless conceivable to design the distributor, which is arranged, for example, in the booth substructure of the powder coating booth of the powder coating system, in a cross-shaped or star-shaped manner, so that the distributor has a plurality (more than two) of outlets in addition to an inlet.

[0062] In particular, it is conceivable that a corresponding flow switching device is provided to selectively establish or disconnect a flow connection between the extraction pipe system or extraction duct system arranged, in particular, in the booth substructure of the at least one powder coating booth of the powder coating system and one of the at least two extraction pipe systems or extraction duct systems leading out of the booth substructure. In this context, it is conceivable, for example, that the flow switching device comprises at least one valve flap or at least one valve slide.

[0063] As already indicated, the powder coating system according to the invention further comprises a powder supply with a powder supply chamber for supplying a powder spraying device (powder spray gun) with coating powder to be sprayed onto the workpiece to be coated as required.

[0064] According to a further aspect of the present invention, it is provided that the powder supply chamber is fluidly connected or connectable to the second raw gas chamber of the second powder separator of the powder separator system via an extraction pipe system or an extraction duct system in order to supply a powder-air mixture from the powder supply chamber to the second raw gas chamber of the second powder separator of the powder separator system. This measure ensures that the powder-air mixture to be discharged from the powder supply chamber of the powder coating system is properly cleaned by the powder separator system. The powder separated in the second powder separator of the powder separator system from the powder-air mixture discharged from the powder waste container chamber is preferably treated as waste powder and fed to a powder waste container.

[0065] Particularly in this context, it is appropriate for the powder coating system to further comprise a powder waste system with a powder waste container chamber for receiving waste powder, wherein the powder waste container chamber is preferably fluidly connected or connectable to the second raw gas chamber of the second powder separator of the powder separator system via an extraction pipe system or extraction duct system in order to feed a powder-air mixture from the powder waste container chamber of the powder waste system to the second raw gas chamber of the second powder separator of the powder separator system. The powder-air mixture thus fed from the powder waste container chamber is cleaned in the second powder separator, i.e. the powder contained in the fed powder-air mixture is separated from the air stream. The separated powder is preferably treated as waste powder and fed back to the powder waste container chamber.

[0066] In order to reuse the powder separated, in particular in the single-color operating mode of the powder coating system, with the aid of the first powder separator of the powder separator system, it is provided in particular that the first powder separator of the powder separator system has a first powder collection area, which is preferably arranged at least partially or regionally below the first raw gas chamber of the first powder separator and is designed to receive at least part of the powder separated with the aid of the first filter medium from the raw gas supplied to the first raw gas chamber of the first powder separator.

[0067] Preferably, the first powder collection area has a first powder discharge outlet, via which the powder collected in the first powder collection area can be fed, as needed, preferably with the aid of a powder feed pump, to a powder supply chamber of the powder coating system. In this way, the powder separated by the first powder separator, particularly in the single-color operating mode of the powder coating system, can be fed back into the powder coating process and thus reused. The invention further relates to a method for operating a powder coating system. The powder coating system is preferably a powder coating system of the type according to the invention described above.

[0068] The method according to the invention provides a powder separator system of the type described above. It is provided that, in the single-color operating mode of the powder coating system, only the first raw gas chamber of the first powder separator is supplied with a powder-air mixture extracted or discharged from a coating booth of the powder coating system as raw gas. Furthermore, it is provided that, in the multi-color operating mode of the powder coating system, only the second raw gas chamber of the second powder separator is supplied with a powder-air mixture extracted or discharged from a coating booth of the powder coating system, which may have previously passed through a centrifugal separator.

[0069] Advantageously, it is further provided that, in particular in the single-color operating mode of the powder coating system and preferably both in the single-color operating mode and in the multi-color operating mode of the powder coating system, only the second raw gas chamber of the second powder separator is further supplied as raw gas with a powder-air mixture extracted or discharged from a powder supply chamber of the powder coating system.

[0070] Alternatively or additionally, it is provided that, in particular in the single-color operating mode of the powder coating system and preferably both in the single-color operating mode and in the multi-color operating mode of the powder coating system, only the second raw gas chamber of the second powder separator is further supplied as raw gas with a powder-air mixture extracted or discharged from a powder waste container chamber of the powder coating system.

[0071] An exemplary embodiment of the present invention will be described in more detail below with reference to the accompanying drawings.

[0072] There are shown: FIG. 1 schematically shows an exemplary embodiment of the powder coating system according to the invention, wherein the powder coating system is operated in a single-color operating mode;

[0073] FIG. 2 schematically shows the exemplary embodiment of the powder coating system according to the invention according to FIG. 1, although here the powder coating system is operated in a multi-color operating mode;

[0074] FIG. 3 shows schematically and in an isometric view a further exemplary embodiment of the coating system according to the invention;

[0075] FIG. 4 schematically and in a further isometric view, the exemplary embodiment of the powder coating system according to the invention according to FIG. 3;

[0076] FIG. 5 schematically and in a (first) isometric view, the powder separator system of the powder coating system according to FIG. 3; and

[0077] FIG. 6 shows a schematic and (second) isometric view of the powder separator system according to FIG. 5.

[0078] FIG. 1 schematically shows an embodiment of a powder coating system 20 according to the invention for spray-coating workpieces or objects with coating powder, which is then melted onto the object or workpiece in a heating furnace (not shown). A control device is provided for controlling the functions of the powder coating system 20. Powder pumps are provided for pneumatically conveying the coating powder from a powder supply chamber 31 to spray guns 33. These can be injectors into which coating powder is sucked from a powder container 36 within the powder supply chamber 31 by means of compressed air serving as conveying air, after which the mixture of conveying air and coating powder then flows together to the spray gun 33.

[0079] Powder pumps can also be used to convey small portions of powder one after the other using compressed air. A small portion of powder is stored in a powder chamber and then expelled from the powder chamber using compressed air. The compressed air remains behind the powder portion and pushes it forward. These pump types are also called "compressed air push pumps" or "droplet conveying pumps."

[0080] Fresh powder from a powder supplier is fed from a fresh powder system 34, which can be, for example, a small container in the form of a dimensionally stable container or a bag with a powder quantity of, for example, between 10 and 50 kg or, for example, a large container, for example, also a dimensionally stable container or a bag with a powder quantity of between 100 kg and 1,000 kg, to a screening device by means of a powder pump 32 in a fresh powder line 35. The coating powder screened by the screening device is fed by gravity or preferably by a powder pump

[0081] 32 is conveyed via at least one powder supply line into an intermediate container chamber of a particularly dimensionally stable intermediate container 36. The volume of the intermediate container chamber is preferably smaller and in particular significantly smaller than the volume of the small fresh powder container.

[0082] The intermediate container 36 for temporarily storing the coating powder has at least one powder pump 32, for example in the form of a thin-phase powder pump (injector) or in the form of a dense-phase powder pump, in order to supply coating powder through corresponding powder lines 37 to spray devices

[0083] 33. The spraying devices 33 may comprise spray nozzles or rotary atomizers for spraying the coating powder onto the workpiece to be coated, which is preferably located in a powder coating booth 21.

[0084] Coating powder that does not adhere to the workpiece is removed from the coating booth 21 as excess powder.

[0085] The coating booth 21 is equipped with an extraction system, via which a powder-air mixture can be removed and in particular extracted from the coating booth 21, particularly during a coating or cleaning operation of the powder coating system 20. The extraction system has a first extraction pipe system or extraction duct system 26 and a second extraction pipe system or extraction duct system 27. Via a corresponding distributor / switch 28, either the first extraction pipe system or extraction duct system 26 or the second extraction pipe system or extraction duct system 27 is in fluid communication with the interior of the booth in order to optionally remove or extract the powder-air mixture from the coating booth 21 via the first extraction pipe system or extraction duct system 26 or the second extraction pipe system or extraction duct system 27.

[0086] In the embodiment of the powder coating system 20 according to the invention shown in FIG. 1 and FIG. 2, it is provided that the first extraction pipe system or extraction channel system 26 is in fluid communication with a first raw gas inlet 6 of a first powder separator 2 of a powder separator system 1.

[0087] The second suction pipe system or suction channel system 27, on the other hand, is in fluid communication with an inlet region 23 of a centrifugal separator 22 designed as a cyclone separator. In the centrifugal separator 22, the powder-air mixture supplied via the second suction pipe system or suction channel system 27 and the inlet region 23 of the centrifugal separator 22 is pre-cleaned.

[0088] In other words, at least a portion of the powder contained in the powder-air mixture is separated in the centrifugal separator 22. The thus pre-cleaned powder-air mixture is fed from the outlet area 24 of the centrifugal separator 22 via a corresponding duct system 38 to a second raw gas inlet 7 of a second powder separator 3 of the powder separation system 1.

[0089] In a single-color operating mode, as indicated in FIG. 1, a fluid connection between the booth interior and the second extraction pipe system or extraction duct system 27 is interrupted. In other words, in the single-color operating mode, the powder-air mixture discharged and, in particular, extracted from the coating booth 21 is fed exclusively via the first extraction pipe system or extraction duct system 26 to the first powder separator 2 of the powder separator system 1. In a multi-color operating mode, however, the fluid connection between the booth interior and the first extraction pipe system or extraction duct system 26 is interrupted. Rather, in this operating mode, as shown in FIG. 2, there is a fluid connection between the second extraction pipe system or extraction duct system 27 and the booth interior.Thus, in the multi-color operating mode, the powder-air mixture discharged and extracted from the coating booth 21 is first fed exclusively to the centrifugal separator 22 and then to the second powder separator 3 serving as a post-filter.

[0090] Regardless of whether the powder coating system 20 is operated in single-color or multi-color mode, a powder supply chamber 31 of the powder supply of the powder coating system 20 is fluidly connected to the second powder separator 3 via an extraction pipe system or extraction channel system 39 in order to supply a powder-air mixture from the powder supply chamber 31 to the second powder separator 3. The powder separated from the powder-air mixture in the second powder separator 3 then enters a powder waste container 30.

[0091] The powder waste container 30 can either be arranged directly below the powder separator 3, especially if smaller amounts of powder waste are expected, or - as shown in FIG. 2 - be integrated into a waste station.

[0092] The powder waste container 30 is accommodated in a powder waste container chamber, for example, as a bag. The powder waste container chamber 30 is also fluidly connected to the second powder separator 3 via an extraction pipe system or extraction channel system 40, in order to supply a powder-air mixture from the powder waste container chamber 30 to the second powder separator 3 of the powder separator system 1. The powder separated from this powder-air mixture into the second powder separator 3 then returns to the powder waste container 30.

[0093] The supply of a powder-air mixture from the powder waste container chamber 30 to the second powder separator 3 and the supply of a powder-air mixture from the powder supply chamber 31 to the second powder separator 3 occurs both in single-color operating mode and in multi-color operating mode of the powder coating system 20. The powder-air mixture discharged from the coating booth 21 in single-color operating mode is cleaned in the first powder separator 2. The cleaned air is discharged as clean gas into the installation room of the powder separator system 1. The powder separated from the powder-air mixture is returned to the powder supply chamber 31 of the powder coating system 20 by means of a powder pump 32 and a powder line 41.

[0094] The powder-air mixture fed to the centrifugal separator 22 in the multi-color operating mode of the powder coating system 20 is pre-cleaned in the centrifugal separator 22. The resulting powder, separated from the powder-air mixture, is fed either to the powder waste system 30 or to the powder supply chamber 31. A corresponding powder pump 32 and a valve arrangement 42 are used for this purpose.

[0095] The powder-air mixture pre-cleaned in the centrifugal separator 22 is then fed to the second powder separator 3, which serves as a post-filter. The powder separated from this powder-air mixture is treated as waste and fed to the powder waste container chamber 30.

[0096] As can be seen in particular from the illustrations in FIG. 5 and FIG. 6, the powder separator system 1 used in the powder coating system 20 has a first powder separator 2 based on filtration technology for the single-color operating mode of the powder coating system 20 and a second powder separator 3 also based on filtration technology for the multi-color operating mode of the powder coating system 20.

[0097] The first powder separator 2 has a first raw gas chamber 4 with a first filter medium (not shown in the drawings) accommodated therein. Similarly, the second powder separator 3 has a second raw gas chamber 5 with a second filter medium (also not shown in the drawings) accommodated therein.

[0098] The first and / or second filter medium can be designed as a plate and / or cartridge filter. The first raw gas chamber 4 has a first raw gas inlet 6, through which the powder-air mixture extracted or discharged from the coating booth 21 of the powder coating system 20 is supplied as raw gas to the first raw gas chamber 4 in the single-color operating mode of the powder coating system 20.

[0099] The second powder separator 3 of the powder separator system 1 has a second raw gas inlet 7, via which the powder-air mixture extracted or discharged from the coating booth 21 of the powder coating system 20, which has previously passed through the centrifugal separator 22, is supplied as raw gas to the second raw gas chamber 5 of the second powder separator 3 in the multi-color operating mode of the powder coating system 20.

[0100] In the embodiment shown in the drawings, it is provided that a powder-air mixture extracted or discharged from the powder supply chamber 31 of the powder coating system 20 is additionally supplied as raw gas to the second raw gas chamber 5 of the second powder separator 3 via the second raw gas inlet 7 of the second powder separator 3, both in the single-color operating mode and in the multi-color operating mode of the powder coating system 20.

[0101] Of course, it is also conceivable here that an additional raw gas inlet is provided for the supply of the powder-air mixture extracted or discharged from the powder supply chamber 31 of the powder coating system 20.

[0102] In the embodiment shown in the drawings, it is further provided that a powder-air mixture extracted or discharged from the powder waste container chamber 30 of the powder coating system 20 is also supplied to the second raw gas chamber 5 as raw gas via the second raw gas inlet 7 of the second powder separator 3.

[0103] Here, too, it is fundamentally conceivable to provide an additional (dedicated) raw gas inlet. Preferably, the powder-air mixture extracted or discharged from the powder supply chamber 31 of the powder coating system 20 and the powder-air mixture extracted or discharged from the powder waste container chamber 30 of the powder coating system 20 are supplied as raw gas to the second powder separator 3, and in particular to the second raw gas chamber of the second powder separator 3, both in single-color operating mode and in multi-color operating mode.

[0104] The powder separator system 1, as shown in particular in FIG. 5 and FIG. 6 using an exemplary embodiment, is characterized in particular in that the two powder separators (ie the first powder separator 2 and the second powder separator 3) are assigned a common clean gas chamber 8, which is in fluid communication with both the first raw gas chamber 4 of the first powder separator 2 and the second raw gas chamber 5 of the second powder separator 3.

[0105] In addition, a common suction fan 9 is assigned to the two powder separators 2, 3 of the powder separator system 1, which is preferably in fluid connection with the common clean gas chamber 8 via a clean gas duct or directly.

[0106] The first powder separator 2 of the powder separator system 1 has a first powder collection area 10, which is arranged at least partially or regionally below the first raw gas chamber 4 and is designed to receive at least a portion of the powder separated from the raw gas supplied to the first raw gas chamber 4 with the aid of the first filter medium.

[0107] The first powder collection area 10 has a first powder discharge outlet 12, via which the powder collected in the first powder collection area 10 can be fed back to the powder supply chamber 31 of the powder coating system 20, preferably with the aid of a powder feed pump 32.

[0108] The second powder separator 3 of the powder separator system 1 also has a second powder collection area 11, which is arranged at least partially or in some areas below the second raw gas chamber 5 and is designed to receive at least a portion of the powder separated from the raw gas supplied to the second raw gas chamber 5 with the aid of the second filter medium. The second powder collection area 11 has a second powder discharge outlet 13, via which the powder collected in the second powder collection area 11 can be fed, as needed, preferably with the aid of a powder feed pump 32, either to the powder waste container chamber 30 of the powder coating system 20 or to the powder supply chamber 31 of the powder coating system 20.

[0109] The powder separator system 1 has a single control device via which the common suction fan 9 can be controlled.

[0110] The invention is not limited to the embodiment shown in the drawings, but results from a combination of all features disclosed herein.

[0111] Reference symbol list

[0112] 1 powder separator system

[0113] 2 first powder separator

[0114] 3 second powder separator

[0115] 4 first raw gas chamber

[0116] 5 second raw gas chamber

[0117] 6 first raw gas inlet

[0118] 7 second raw gas inlet

[0119] 8 Clean gas chamber

[0120] 9 suction fans

[0121] 10 first powder collection area

[0122] 11 second powder collection area

[0123] 12 first powder discharge outlet

[0124] 13 second powder discharge outlet

[0125] 20 powder coating systems

[0126] 21 Coating booth

[0127] 22 centrifugal separators

[0128] 23 Inlet area of ​​the centrifugal separator

[0129] 24 Outlet area of ​​the centrifugal separator

[0130] 25 Duct or pipe system between centrifugal separator and second powder separator

[0131] 26 first extraction pipe system or extraction duct system

[0132] 27 second extraction pipe system or extraction duct system

[0133] 28 Distributor / Switcher

[0134] 29 Powder outlet of the centrifugal separator

[0135] 30 Powder waste container chamber / powder waste container

[0136] 31 Powder supply container / powder supply

[0137] 32 Powder pump

[0138] 33 Spray gun / spray device

[0139] 34 Fresh powder system

[0140] 35 Fresh powder line

[0141] 36 intermediate containers

[0142] 37 Powder line

[0143] 38 canal system

[0144] 39 Suction pipe system / suction pipe system

[0145] 40 Suction pipe system / suction channel system

[0146] 41 Powder line

[0147] 42 Valve arrangement

Claims

Patent claims 1. Powder separator system (1) for a powder coating system (20) which can be operated selectively in a single-color operating mode or in a multi-color operating mode, wherein the powder separator system (1) comprises: a first powder separator based on filtration technology (2) for the single-color operating mode of the powder coating system (20); and a second powder separator based on filtration technology (3) for the multi-color operating mode of the powder coating system (20), wherein the first powder separator (2) has a first raw gas chamber (4) with a first filter medium accommodated therein and the second powder separator (3) has a second raw gas chamber (5) with a second filter medium accommodated therein, wherein the first raw gas chamber (4) has a first raw gas inlet (6) via which a powder-air mixture extracted or discharged from a coating booth (21) of the powder coating system (20) can be supplied as raw gas to the first raw gas chamber (4) in the single-color operating mode of the powder coating system (20), wherein the second raw gas chamber (5) has a second raw gas inlet (7) via which a powder-air mixture extracted or discharged from a coating booth (21) of the powder coating system (20) can be supplied as raw gas to the second raw gas chamber (5) in the multi-color operating mode of the powder coating system (20). Powder-air mixture, which mayhas previously passed through a centrifugal separator (22), wherein a common clean gas chamber (8) is assigned to the two powder separators (2, 3). which is in fluid communication with both the first raw gas chamber (4) and the second raw gas chamber (5), and wherein a common suction fan (9) is assigned to the two powder separators (2, 3), which is preferably in fluid communication with the common clean gas chamber (8) via a clean gas channel.

2. Powder separator system (1) according to claim 1, wherein the second raw gas inlet (7) of the second powder separator (3) is further designed, in particular in the single-color operating mode of the powder coating system (20) and preferably both in the single-color operating mode and in the multi-color operating mode of the powder coating system (20), to supply a powder-air mixture extracted or discharged from a powder supply chamber (31) of the powder coating system (20) to the second raw gas chamber (5) as raw gas;or wherein the second raw gas chamber (5) of the second powder separator (3) has a third raw gas inlet, via which a powder-air mixture extracted or discharged from a powder supply chamber (31) of the powder coating system (20) can be supplied as raw gas to the second raw gas chamber (5), in particular in the single-color operating mode of the powder coating system (20) and preferably both in the single-color operating mode and in the multi-color operating mode of the powder coating system (20); 3. Powder separator system (1) according to claim 1 or 2, wherein the second raw gas inlet (7) of the second powder separator (3) is further designed, in particular in the multi-color operating mode of the powder coating system (20) and preferably both in the single-color operating mode and in the multi-color operating mode of the powder coating system (20), to supply a powder-air mixture extracted or discharged from a powder waste container chamber (30) of the powder coating system (20) as raw gas to the second raw gas chamber (5); or wherein the second raw gas chamber (5) of the second powder separator (3) has a fourth raw gas inlet, via which the second raw gas chamber (5), in particular in the multi-color operating mode of the Powder coating system (20) and preferably both in the single-color operating mode and in the multi-color operating mode of the powder coating system (20) to supply a powder-air mixture extracted or discharged from a powder waste container chamber (30) of the powder coating system (20) to the second raw gas chamber (5).

4. Powder separator system (1) according to claim 1, wherein the second raw gas chamber (5) has a third raw gas inlet, via which a powder-air mixture extracted or discharged from a powder supply chamber (31) of the powder coating system (20) can be supplied as raw gas to the second raw gas chamber (5), in particular in the single-color operating mode of the powder coating system (20) and preferably both in the single-color operating mode and in the multi-color operating mode of the powder coating system (20), and via which a powder-air mixture extracted or discharged from a powder waste container chamber (30) of the powder coating system (20) can be supplied to the second raw gas chamber (5), in particular in the multi-color operating mode of the powder coating system (20) and preferably both in the single-color operating mode and in the multi-color operating mode of the powder coating system (20).

5. Powder separator system (1) according to one of claims 1 to 4, wherein the first powder separator (2) has a first powder collection area (10) which is arranged at least partially or regionally below the first raw gas chamber (4) and is designed to receive at least a portion of the powder separated from the raw gas supplied to the first raw gas chamber (4) with the aid of the first filter medium, wherein the first powder collection area (10) has a first powder discharge outlet (12) via which the powder collected in the first powder collection area (10) can be fed, as required, preferably with the aid of a powder feed pump (32), to a powder supply chamber (31) of the powder coating system (20).

6. Powder separator system (1) according to one of claims 1 to 5, wherein the second powder separator (3) has a second powder collecting area (11) which is at least partially or regionally below the second raw gas chamber (5) and is designed to receive at least a portion of the powder separated from the raw gas supplied to the second raw gas chamber (5) with the aid of the second filter medium, wherein the second powder collecting region (11) has a second powder discharge outlet (13) via which, as required, the powder collected in the second powder collecting region (11) can be fed, preferably with the aid of a powder feed pump (32), in particular selectively to a powder waste container chamber (30) of the powder coating system (20) or a powder supply chamber (31) of the powder coating system (20) or a powder waste container chamber of the second powder separator (3).

7. Powder separator system (1) according to one of claims 1 to 6, wherein the first filter medium is designed as a plate and / or cartridge filter; and / or wherein the second filter medium is designed as a plate and / or cartridge filter.

8. A powder coating system (20) for powder coating workpieces, wherein the powder coating system (20) can be operated selectively in a single-color operating mode or in a multi-color operating mode and comprises the following: at least one coating booth (21) in which the workpiece can be coated with powder; at least one extraction system, via which a powder-air mixture can be removed and in particular extracted from the at least one coating booth (21), in particular during a coating or cleaning operation of the powder coating system (20); and a powder separator system (1) according to one of claims 1 to 7 for cleaning the powder-air mixture removed and in particular extracted from the at least one coating booth (21).

9. Powder coating system (20) according to claim 8, wherein the powder coating system (20) further comprises a centrifugal separator (22) which is designed to separate at least part of the powder in the powder coating system (20) from the at least one coating booth (21) to separate the powder contained in the removed and in particular extracted powder-air mixture from the powder-air mixture.

10. Powder coating system (20) according to claim 9, wherein the centrifugal separator (22) is preferably designed as a cyclone separator and in particular as a tangential cyclone separator and has an inlet region (23) for supplying the powder-air mixture discharged and in particular sucked out from the at least one coating booth (21) and an outlet region (24) for discharging the powder-air mixture pre-cleaned in the centrifugal separator (22).

11. Powder coating system (20) according to claim 10, wherein the outlet region (24) of the centrifugal separator (22) is or can be fluidly connected to the second raw gas inlet (7) of the powder separator system (1) via a channel or line system (38).

12. Powder coating system (20) according to claim 10 or 11, wherein the at least one coating booth (21) is a An extraction pipe system or extraction channel system (26, 27) is assigned for the required removal of the powder-air mixture from the at least one coating booth (21), wherein the extraction pipe system or extraction channel system (26, 27) is fluidically connectable optionally to the first raw gas inlet (6) of the powder separator system (1) or to the inlet region (23) of the centrifugal separator (22).

13. Powder coating system (20) according to one of claims 9 to 12, wherein the centrifugal separator (22) has a powder outlet which, if required, can be connected via a powder line to a powder waste container of the powder coating system (20); and / or wherein the centrifugal separator (22) has a powder outlet which, if required, can be connected via a powder line to a powder supply container (36) of a powder supply of the powder coating system (20).

14. Powder coating system (20) according to one of claims 8 to 13, wherein the powder coating system (20) further comprises a powder supply with a powder supply chamber (31) for supplying a powder spraying device (33) with coating powder to be sprayed onto the workpiece to be coated as required, wherein the powder supply chamber (31) is or can be connected in terms of flow to the second raw gas chamber (5) of the powder separator system (1) via an extraction pipe system or extraction channel system (39) for supplying a powder-air mixture from the powder supply chamber (31) to the second raw gas chamber (5) of the powder separator system (1).

15. Powder coating system (20) according to one of claims 8 to 14, wherein the powder coating system (20) further comprises a powder waste system with a powder waste container chamber (30) for receiving waste powder, wherein the powder waste container chamber (30) is fluidly connected or connectable to the second raw gas chamber (5) of the powder separator system (1) via an extraction pipe system or extraction channel system (40) for supplying a powder-air mixture from the powder waste container chamber (30) to the second raw gas chamber (5) of the powder separator system (1).

16. Powder coating system (20) according to one of claims 8 to 15, wherein the first powder separator (2) of the powder separator system (1) has a first powder collection area (10) which is arranged at least partially or in regions below the first raw gas chamber (4) and is designed to receive at least a portion of the powder separated from the raw gas supplied to the first raw gas chamber (4) with the aid of the first filter medium, wherein the first powder collection area (10) has a first powder discharge outlet (12) via which, if required, the powder collected in the first powder collection area (10) can be discharged, preferably with the aid of a powder feed pump (32) can be fed to a powder supply chamber (31) of the powder coating system (20).

17. Method for operating a powder coating system (20), in particular a powder coating system (20) according to one of the Claims 8 to 16, wherein the method comprises the following method steps: Providing a powder separator system (1) according to one of claims 1 to 7, wherein in the single-color operating mode of the powder coating system (20) only the first raw gas chamber (4) of the first powder separator (2) is supplied as raw gas a powder-air mixture extracted or discharged from a coating booth (21) of the powder coating system (20), and wherein in the multi-color operating mode of the powder coating system (20) only the second raw gas chamber (5) of the second powder separator (3) is supplied as raw gas a powder-air mixture extracted or discharged from a coating booth (21) of the powder coating system (20), which may have previously passed through a centrifugal separator (22).

18. The method according to claim 17, wherein, in particular in the single-color operating mode of the powder coating system (20) and preferably both in the single-color operating mode and in the multi-color operating mode of the powder coating system (20), only the second raw gas chamber (5) of the second powder separator (3) is further supplied as raw gas with a powder-air mixture extracted or discharged from a powder supply chamber (31) of the powder coating system (20).

19. The method according to claim 17 or 18, wherein, in particular in the single-color operating mode of the powder coating system (20) and preferably both in the single-color operating mode and in the multi-color operating mode of the powder coating system (20), only the second raw gas chamber (5) of the second powder separator (3) is further supplied as raw gas with a powder-air mixture extracted or discharged from a powder waste container chamber (30) of the powder coating system (20).

Images