Method and apparatus for separating overspray, as well as a system with such a method and apparatus

Abstract

Method for separating overspray from the overspray-laden cabin air of coating systems, in particular of painting systems, in which the overspray is picked up by an air stream and directed to a separation device (42) where a large proportion of at least the solids are separated from the overspray, where the cabin air loaded with overspray is passed through filter modules (40) in which overspray is separated and which are designed as replaceable disposable units with filter housing (46) and filter unit (52), wherein each filter module (40) is replaced with an empty filter module (40) after reaching a limit load with overspray, characterized by the fact that the airflow loaded with overspray is directed via an air duct (38) to a filter module (40); and the filter module (40) is detachably connected to the air duct (38).

Description

[0001] The invention relates to a method for separating overspray from the cabin air of coating systems, in particular painting systems, which is loaded with overspray, in which the overspray is picked up by an airflow and led to a separation device where a large proportion of at least the solids are separated from the overspray, wherein the cabin air loaded with overspray is passed through filter modules in which overspray is separated and which are designed as replaceable disposable units with filter housing and filter unit, wherein each filter module is replaced with an empty filter module after reaching a limit load with overspray.

[0002] Furthermore, the invention relates to a device for separating overspray from the cabin air of coating systems, in particular painting systems, which is loaded with overspray. a) the separation device operates with filter modules through which cabin air loaded with overspray can be directed and in which overspray is separated; b) the filter modules are designed as replaceable disposable units with filter housing and filter unit; c) the separation device comprises means by which each filter module can be replaced with an empty filter module after reaching a limit load with overspray.

[0003] Furthermore, the invention relates to a system for coating, in particular for painting, objects, especially vehicle bodies, with a) a coating booth in which the objects can be coated with coating material and through which an airflow can be directed that captures and removes the resulting overspray of the coating material; b) a separation device to which this cabin air can be supplied and where a large proportion of at least the solids from the overspray are separated.

[0004] During the manual or automatic application of coatings to objects, a portion of the coating, which generally contains both solids and / or binders as well as solvents, is not applied to the object. This portion is known in the industry as "overspray." Hereinafter, the terms overspray, overspray particles, or overspray solids are always understood to refer to a dispersed system, such as an emulsion or suspension, or a combination thereof. The overspray is captured by the airflow in the spray booth and collected by a separator, so that the air can be returned to the coating booth after appropriate conditioning, if necessary.

[0005] Wet scrubber systems are particularly common in systems with high paint consumption, such as those used for painting vehicle bodies. In commercially available wet scrubbers, water flows together with the exhaust air from the cabin above to a nozzle that accelerates the airflow. Within this nozzle, the exhaust air is swirled with the water. During this process, the overspray particles largely pass into the water, so that the air leaving the wet scrubber is essentially clean, and the paint overspray particles are detachable and contained within the water. They can then be recovered or disposed of.

[0006] Conventional wet scrubbers require a relatively large amount of energy to circulate the considerable volumes of water needed. The treatment of the rinse water is costly due to the high use of paint-binding and de-sticking chemicals and the disposal of the paint sludge. Furthermore, the air absorbs a significant amount of moisture through intensive contact with the rinse water, which, in recirculation mode, results in high energy consumption for air conditioning.

[0007] In contrast, commercially available devices of the type mentioned above use a dry separation process. Electrostatic separators have become particularly established in this regard. In these devices, the paint overspray is guided past a separation surface and deposited there by ionizing the overspray particles with an electrode assembly. Due to the electric field generated between the separation surface and the electrode assembly, the particles migrate to the separation surface. The paint overspray particles adhering to the separation surface can then be mechanically scraped off and removed.

[0008] The cleaning effect of such separators is indeed very high. However, for continuous operation, it is essential to ensure that a sufficiently strong electric field can always develop between the separation surface and the electrode assembly. This is only possible up to a certain thickness of paint overspray on the separation surface, as such a layer acts as an insulator. The necessary continuous removal of the paint overspray from the separation surface, however, involves structurally complex measures and can be prone to malfunctions. Furthermore, overspray can sometimes react, harden, or dry on the separation surface in such a way that it can no longer be removed by simply wiping it off. In addition, the energy consumption of such separators is relatively high.

[0009] Furthermore, a separation device with partially regenerated reusable filter bodies is known from GB 2 063 099 A. Separation concepts with filter inserts without their own filter housing or filter as such are described in DE 10 2005 013 708 A1, DE 20 2005 013 403 U1 and WO 2003 / 084 638 A2.

[0010] The object of the present invention is therefore to provide a method, a separation device and a system of the type mentioned above which take these problems into account.

[0011] This task is solved in a procedure of the type mentioned above by the fact that the airflow loaded with overspray is directed via an air duct to a filter module; and The filter module is detachably connected to the air duct.

[0012] The invention is based on the finding that, contrary to popular belief, disposable filter modules are cost-effective and also environmentally friendly. The processing and / or disposal of such disposable filter modules is more energy-efficient and resource-efficient than the effort required for a separation device in which the separated paint is removed from existing separation surfaces in a continuous process.

[0013] For these reasons, it is therefore advantageous if a replaced filter module loaded with overspray is sent to a disposal and / or recycling process.

[0014] Using an inertial filter as the filter unit has proven particularly effective. An inertial filter can advantageously operate without an external energy supply and effectively removes overspray.

[0015] With regard to a separation device of the type mentioned above, the aforementioned problem is solved by the fact that d) the airflow loaded with overspray can be directed to a filter module via an air duct; e) the filter module is detachably connectable to the air duct.

[0016] The advantages correspond to those explained above regarding the procedure.

[0017] The air duct deflects the cabin air by 90° into a horizontal direction, whereupon it flows into a filter module in a completely horizontal direction.

[0018] Similarly, it is advantageous if the filter unit is designed as an inertial filter.

[0019] To achieve a high separation efficiency, it is particularly advantageous if the filter unit comprises a large number of separation elements arranged in such a way that a flow labyrinth is formed.

[0020] Preferably, the separating elements are oriented vertically and are surrounded by cabin air flow in a horizontal direction. The overspray can then flow downwards along the separating elements.

[0021] If the distance between the separating elements decreases in the direction of flow and / or in a direction perpendicular to the direction of flow, overspray particles still present in the cabin air at the end of the flow path through the filter unit are effectively separated.

[0022] In practice, filter lamellae, filter sleeves, compartment structures or chamber structures have proven to be advantageous as separation elements.

[0023] If a filter module includes a base section designed as a standardized support structure, it can be conveyed using known conveying systems that are already adapted to such standardized support structures.

[0024] With regard to the processing or disposal of the disposable filter module, it is particularly advantageous if one component, several components or all components of the filter module are made from a wet-strength recycled material.

[0025] The wet-strength recycled material preferably chosen is one or more of the following: paper and cardboard, corrugated cardboard, standing flute cardboard, honeycomb cardboard or wrapping cardboard, MDF, wood. Plastics such as polyethylene or polypropylene are also suitable.

[0026] It can be advantageous if the filter module is designed as a modular kit. In this case, a filter module can be assembled on-site and transported to its place of use in a space-saving manner, e.g., folded up.

[0027] To effectively capture separated overspray, it is advantageous if the filter module includes a collection tray in which separated overspray collects.

[0028] The collection tray can, for example, include a collection bag which is located at the bottom of the filter module.

[0029] The aforementioned problem is solved in a plant of the type mentioned at the outset by including a separation device with some or all of the aforementioned features.

[0030] The advantages that can be achieved thereby correspond to the advantages explained above for the separation device.

[0031] Exemplary embodiments of the invention are explained in more detail below with reference to the drawings. These show: Fig. 1. A paint booth of a surface treatment plant with an overspray separation device in a front view; Fig. 2. A section of the paint booth on a larger scale. Fig. 1 along the intersection line II-II there; Fig. 3 a perspective view of a filter module of the separation device, showing part of a filter housing broken off; Fig. 4 one of the Fig. 3. Corresponding perspective view of a modified filter module; Fig. 5 on an enlarged scale, one of the Fig. 1 corresponding view of a modified separation area of ​​the paint booth; Fig. 6 one of the Fig. 4. A corresponding view of a further modified filter module; Fig. 7 a side view of the filter module after Fig. 6, showing a cross-section of a collection tray.

[0032] In Fig. 1 together with 2 denotes a paint booth of a surface treatment plant in which vehicle bodies 4 are painted after they have been cleaned and degreased, for example, in upstream pretreatment stations (not shown) in paint booth 2. The paint booth 2 rests on a steel structure 6, as is known per se.

[0033] The paint booth 2 comprises a top-mounted paint tunnel 8, which is bounded by vertical side walls 10 and a horizontal booth ceiling 12, but is open at the ends. Furthermore, the paint tunnel 8 is open at the bottom in such a way that exhaust air laden with overspray can flow downwards. The booth ceiling 12 is designed in the usual manner as the lower boundary of an air supply chamber 14 with a filter ceiling 16.

[0034] Above a lower opening 18 of the paint tunnel 8, a steel frame 20 is arranged, which supports a conveyor system 22 known per se, which will not be described in detail here. This system transports vehicle bodies 4 to be painted from the entrance side of the paint tunnel 8 to its exit side. Inside the paint tunnel 8 are application devices in the form of multi-axis application robots 24, which are known per se. The vehicle bodies 4 can be coated with paint by means of the application robots 24.

[0035] The lower opening 18 of the paint tunnel 8 is covered by a walkable grating 26. Below the grating 26 is a system area 28 in which the overspray particles carried by the cabin air are separated from the cabin air.

[0036] Air flows from the air supply chamber 14 downwards through the painting tunnel 8 to the plant area 28, whereby the air picks up and carries away the paint overspray present in the painting tunnel 8.

[0037] The system area 28 comprises a flow area 30 into which the cabin air laden with overspray initially flows. This area is open upwards towards the paint booth 2, but bounded laterally by the side walls 10 and downwards by an intermediate ceiling 32. The intermediate ceiling 32 has several passages 34 arranged one behind the other in the longitudinal direction of the cabin. Each of these passages 34 leads to a duct inlet 36 of a respective air duct 38, into which the cabin air laden with overspray particles initially flows vertically downwards.

[0038] The air duct 38 then deflects the cabin air by 90° into the horizontal direction, whereupon it flows in a completely horizontal direction into a filter module 40. Each filter module 40 forms a separation unit, with which a separation device designated 42 operates, which is located in a separation area 44 of the paint booth 2, which is arranged below the flow area 30.

[0039] Each filter module 40 is detachably connected to one of the air ducts 38. For this purpose, each filter module 40 has a filter housing 46 with a filter inlet 48, which is designed to be complementary to a duct outlet 50 of the air duct 38, so that the filter module 40 can be fluidically connected to or detached from the duct outlet 50 of the air duct 38 by a corresponding horizontal movement.

[0040] In the present embodiment, the separation device 42 is therefore a separation filter modularly constructed from the filter modules 40.

[0041] The cabin air is deflected twice by 90° within the filter module 40, then flows through a filter unit in the form of an inertial filter 52, where the paint overspray is separated, and exits the filter module 40 through a filter outlet nozzle 54 on the same side of the filter housing 46 as the filter inlet 48. From there, the cabin air, now largely free of overspray particles, flows into an intermediate channel 56, through which it enters a collecting flow channel 58.

[0042] The intermediate channel 56 has an inlet flange 60, whereby the filter outlet nozzle 54 of the filter module 40 can be fluidically connected to or disconnected from this inlet flange 60 by its aforementioned horizontal movement. Thus, a filter module 40 is ready for operation in an operating position when its filter inlet 48 is connected to the channel outlet nozzle 50 of the air duct 38 and its filter outlet nozzle 54 is connected to the inlet flange 60 of the intermediate channel 56.

[0043] The cabin air is fed via the collecting flow channel 58 to further processing and conditioning and subsequently returned to the air supply chamber 14 in a circuit not shown here, from which it flows back into the paint tunnel 8 from above. If the cabin air is not yet sufficiently free of overspray particles after passing through the separator filter 42, further filter stages can be added downstream of the separator filter 42. The cabin air is fed into these stages, and these stages may contain, for example, fleece filters or electrostatic separator filters, as are commonly known. Optionally, one or more of these additional filter stages can also be integrated into the filter module 40. For example, a filter fleece can be arranged in front of the filter outlet nozzle 54.

[0044] Based on Fig. Section 3 now explains one of the filter modules 40 in more detail. As can be seen there, the filter housing 46 of the filter module 40 defines a flow chamber 62, which extends between the filter inlet 48 and the filter outlet nozzle 54 and through which the cabin air flows on a flow path curved by 180°.

[0045] The filter housing 46, in turn, comprises a base section 64 and a chamber cover 66, which is supported by the base section 64 and in which one chamber wall has the filter inlet 48 and the filter outlet nozzle 54. The base section 64 is designed in its geometry and dimensions as a standardized support structure and, for example, according to the specifications of a so-called Euro pallet. In this way, a filter module 40 can be moved and brought into or removed from its operating position using a conveying system 68 adapted to such standard structures. This is in Fig. 1 indicated by the example of a manually operated pallet truck 70.

[0046] The arrangement of the filter modules 40 in the separation area 44 of the paint booth 2 can accordingly be carried out according to a grid which is based on the standardized floor part 64 used.

[0047] At least one lower collection area of ​​the filter module 40 is liquid-tight and thus designed as a collection tray 72 for paint, which separates at the inertial filter 52 and flows downwards in it.

[0048] The inertial filter 52 is arranged in the flow chamber 62 in front of the filter outlet nozzle 54 such that the cabin air laden with overspray flows through it in a horizontal direction 74. The inertial filter 52 comprises a support structure 76 with a largely horizontal support plate 78 – as shown in Fig. As can be seen in Figure 3, the support plate 78 is slightly inclined downwards in the direction of flow of the cabin air entering the filter module 40 relative to the horizontal - which is attached inside to the housing wall of the filter housing 46 with the filter inlet 48 and the filter outlet nozzle 54.

[0049] The support plate 78 carries a plurality of filter lamellae 80 extending downwards towards the collection tray 72 as separation elements, of which, for the sake of clarity, only some are provided with a reference numeral. This can be done, as in the present embodiment, for example, by the support plate 78 having slots 82 complementary to the filter lamellae 80, into which the filter lamellae 80 are inserted. Only some of the slots 82 are also provided with a reference numeral.

[0050] The filter lamellae 80 are V-shaped in cross-section and arranged such that the apex of the V points in the direction of airflow 74, in which the cabin air flows through the inertial filter 52. The filter lamellae 80 are arranged offset from one another, with the number of filter lamellae 80 increasing in the direction of airflow 74. In other words, the distance between the filter lamellae 80 decreases in the direction of airflow 74 and in a direction perpendicular to it, i.e., in this case, the horizontal direction. This principle is described in Fig. Figure 2 illustrates an exchange filter module 84 shown in a vertical section, against which a fully loaded filter module 40 is to be exchanged.

[0051] In this way, a flow labyrinth through which the cabin air flows is formed in the direction of flow 74 in the inertial filter 52, in which the overspray particles are separated on the filter lamellae 80 in a manner known per se according to the principle of inertia. From there, the overspray flows downwards into the collection tray 72, where it accumulates to form a paint pool.

[0052] Instead of the filter lamellae 80, separating elements with different geometry and dimensions can also be used. Fig. Figure 4 shows a modified filter module 40 in which filter sleeves 86 are supported by the support plate 78 of the support structure 76 instead of the filter lamellae 80. The filter sleeves 86 are arranged according to the same principle as the filter lamellae 80 in the filter module 40 according to Figure 4. Fig. 3. In practice, other arrangements of the separating elements may also be provided.

[0053] Instead of filter lamellae 80 or filter sleeves 86, compartment structures or chamber structures can also be used as separation elements. Compartment structures can, for example, consist of foldable or pluggable lamellae or plates connected to one another. In practice, chamber structures are constructed in a honeycomb-like manner.

[0054] As in Fig. As can be seen in Figure 1, the filter module 40 rests in its operating position on a scale 88 and is locked in its operating position at the top and bottom by means of a locking device 90.

[0055] Each filter module 40 is designed to hold a maximum amount of paint, i.e., a limiting load including overspray, which depends on the design of the filter module 40 and the materials used. The amount of paint already held can be monitored using the scale 88. Alternatively, the limiting load can be determined by measuring the differential pressure. The greater the load on the filter module 40, the greater the air resistance it creates.

[0056] When a filter module 40 reaches its maximum capacity, the locking device 90 is released, the fully loaded filter module 40 is moved out of the separation area 44 of the paint booth 2 by the lifting conveyor 70 and replaced with an empty filter module 40. Beforehand, the flow connection of the filter module 40 to be replaced with the guide channel 38 and the connecting channel 56 is interrupted by closing the channel outlet 50 of the guide channel 38 and the inlet flange 60 of the connecting channel 56 by means of locking slides (not shown).

[0057] Once the empty filter module 40 has been moved into its operating position on the scale 88, it is locked in place by the locking device 90, thus preventing it from unintentionally moving out of the separation area 44. The locking slides of the guide channel 38 and the connecting channel 56 are then returned to an open position, allowing cabin air to flow through the newly positioned filter module 40.

[0058] The replaced filter module 40, which is loaded with overspray, is then sent to a disposal and / or recycling process and is thus used as a disposable filter module.

[0059] In other words, the filter modules 40, in which overspray is deposited, are designed as replaceable disposable units with filter housing 46 and filter unit 52, wherein each filter module 40 is replaced with an empty filter module 40 after reaching a limit load with overspray.

[0060] In Fig. Figure 5 shows a modified conveyor system 68. Instead of a pallet truck, a roller conveyor system 92 is shown, which comprises roller tracks with motor-driven rollers in a manner known per se. Using the roller conveyor system 92, filter modules 40, whose capacity for absorbing paint overspray is exhausted, can be computer-controlled and removed from the separation area 44 of the paint booth 2 and replaced by an unloaded filter module 40. For this purpose, the roller conveyor system 92 comprises cooperating conveying units with which filter modules 40 can be moved parallel and / or transversely to the longitudinal extent of the paint booth 2.

[0061] The base 64, the chamber housing 66, the support structure 76, and the separation elements 80, 86 of the filter module 40 are made of a wet-strength recycled material. In general terms, one component, several components, or all components of the filter module 40 are made of a wet-strength recycled material. Suitable materials include, for example, cellulose-based materials such as treated paper and cardboard, corrugated cardboard, standing-flute cardboard, honeycomb cardboard, or wrapping boxes, as well as other materials such as MDF. A wooden Euro pallet, for instance, is also suitable as the base 64. Plastics, particularly polyethylene or polypropylene, are also suitable.

[0062] The filter module 40 itself can be supplied as a modular kit consisting of the aforementioned components in individual parts and assembled on site. The chamber housing 66, for example, can have a hinged lid and be folded along two diagonally opposite longitudinal edges to form a two-layer housing panel. The unfolded chamber housing 66 is then placed, for example, over the inertial filter 52, which was previously assembled from the support structure 76 and the filter lamellae 80 or the filter sleeves 86.

[0063] After the inertial filter 52 has been attached to the chamber housing 66, this assembly is placed on the base part 64 and, if necessary, glued to it.

[0064] To form the collection basin 72, a sealing compound can be injected into the bottom area and distributed evenly in the bottom area of ​​the flow chamber 62 by means of a wobble table.

[0065] In the Fig. 6 and Fig. Figure 7 shows an alternative collection tray 94. In this tray, the base 64 supports a surrounding tray frame 96, which can also be made of one of the aforementioned wet-resistant recycled materials, e.g., thin wooden boards. A liquid-tight collection bag 98 is inserted into the tray frame 96, into which the chamber housing 66 can be placed, with its upper edge folded outwards over the tray frame 96. In practice, it has been found that so-called big bags, which are commonly used as containers for, for example, paint powder, can be used as the collection bag 98.

[0066] Due to the modular design of the separation device 42, it can be designed to be so compact that it can be arranged as a complete unit within the clear contour of the paint booth 2, which in the present embodiments is defined by the steel structure 6. This is in Fig.1 is clearly visible. In this way, the floor space required for the paint booth 2 is not increased by the separator device 42. This means that even already installed paint booths can be retrofitted with the separator device 42. This compactness of the separator device 42 as a whole is due to the small-scale design of the individual filter modules 40.

Claims

[1] Method for separating overspray from the overspray-laden cabin air of coating plants, in particular of painting plants, in which the overspray is picked up by an air stream and directed to a separation device (42) where a large proportion of at least the solids are separated from the overspray, where the cabin air loaded with overspray is passed through filter modules (40) in which overspray is separated and which are designed as replaceable disposable units with filter housing (46) and filter unit (52), wherein each filter module (40) is replaced with an empty filter module (40) after reaching a limit load with overspray, characterized by , that the airflow loaded with overspray is directed via an air duct (38) to a filter module (40); and the filter module (40) is detachably connected to the air duct (38). [2] Method according to claim 1, characterized by , that a replaced filter module (40) loaded with overspray is sent to a disposal and / or recycling process. [3] Method according to claim 1 or 2, characterized by , that an inertial filter is used as the filter unit (52). [4] Device for separating overspray from the overspray-laden cabin air of coating systems, in particular of painting systems, in which a) the separation device (42) operates with filter modules (40) through which cabin air loaded with overspray can be directed and in which overspray is separated; b) the filter modules (40) are designed as replaceable disposable units with filter housing (46) and filter unit (52); c) the separation device (42) comprises means (38, 56, 68, 90) by which each filter module (40) can be replaced with an empty filter module (40) after reaching a limit load with overspray; characterized by , that d) the overspray-laden airflow can be directed via an air duct (38) to a filter module (40); e) the filter module (40) can be detachably connected to the air duct (38). [5] Separation device according to claim 4, characterized by , that the air duct (38) deflects the cabin air by 90° into the horizontal direction, so that it flows into the filter module (40) in a generally horizontal direction. [6] Separation device according to claim 4 or 5, characterized by , that the filter unit (52) is designed as an inertial filter. [7] Separation device according to claim 6, characterized by, that the filter unit (52) comprises a plurality of separation elements (80; 86) arranged to form a flow labyrinth. [8] Separation device according to claim 6, characterized by , that the separating elements (80; 86) run vertically and are surrounded by cabin air in a horizontal direction (74). [9] Separation device according to claim 7 or 8, characterized by , that the distance between the separating elements (80; 86) decreases in the direction of flow (74) and / or in a direction perpendicular to the direction of flow (74). [10] Separation device according to one of claims 7 to 9, characterized by , that filter lamellae, filter sleeves, compartment structures or chamber structures are present as separation elements (80; 86). [11] Separation device according to any one of claims 4 to 10, characterized by , that a filter module (40) comprises a base section (64) designed as a standardized support structure. [12] Separation device according to any one of claims 4 to 11, characterized by , that one component, several components or all components of the filter module (40) are made from a wet-strength recycled material. [13] Separation device according to claim 12, characterized by , that one or more of the following materials is chosen as the wet-strength recycled material: Paper and cardboard materials, corrugated cardboard, standing flute cardboard, honeycomb cardboard or wrapping cardboard, MDF material, wood or plastics, especially polyethylene or polypropylene. [14] Separation device according to any one of claims 4 to 13, characterized by , that the filter module (40) is designed as a modular kit. [15] Separation device according to any one of claims 4 to 14, characterized by , that the filter module (40) includes a collection tray (72; 94) in which separated overspray collects. [16] Separation device according to claim 15, characterized by , that the collection tray (94) includes a receiving bag (98) which is located at the bottom of the filter module (40). [17] Plant for coating, in particular for painting objects, especially vehicle bodies, with a) a coating booth (2) in which the objects (4) can be coated with coating material and through which an airflow can be directed to capture and remove any overspray of the coating material that may occur; b) a separation device (42) to which this cabin air can be supplied and where a large proportion of at least the solids from the overspray are separated, characterized by , that c) the separation device (42) is designed according to one of claims 4 to 16.

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