Title of Invention	PAINTING LINE COMPRISING A DEVICE FOR SEPARATING WET PAINT OVERSPRAY
Abstract	The invention relates to a device for removing wet paint overspray from an outgoing air flow (120) containing over-spray particles. Said overspray-particles reach into an application area (108) of a paint installation in an outgoing airflow (120), which enables the wet paint overspray to the removed from the outgoing air flow (120) in a simple, reliable and time-saving manner. According to the invention, the device comprises at least one removal device (145) which is used to remove the overspray from at least one part of the outgoing air flow (120), which comprises at least one regeneratable surface filter (146), and that the flow path of the outgoing air flow (120) comprises at least one narrow area (140) from the application area (108) to the removal device (145). The central flow direction of the outgoing air flow (120) remains essentially the same when passing through the narrow area (140).

Title of Invention

PAINTING LINE COMPRISING A DEVICE FOR SEPARATING WET PAINT OVERSPRAY

Abstract

The invention relates to a device for removing wet paint overspray from an outgoing air flow (120) containing over-spray particles. Said overspray-particles reach into an application area (108) of a paint installation in an outgoing airflow (120), which enables the wet paint overspray to the removed from the outgoing air flow (120) in a simple, reliable and time-saving manner. According to the invention, the device comprises at least one removal device (145) which is used to remove the overspray from at least one part of the outgoing air flow (120), which comprises at least one regeneratable surface filter (146), and that the flow path of the outgoing air flow (120) comprises at least one narrow area (140) from the application area (108) to the removal device (145). The central flow direction of the outgoing air flow (120) remains essentially the same when passing through the narrow area (140).

Full Text	Device for Separating Wet Paint Overspray The present invention relates to a device for separating wet paint overspray from an exhaust air flow containing overspray particles, wherein the overspray particles pass into the exhaust air flow in an application zone of a painting line. Such devices are used in assemblies for painting workpieces, in particular for spray painting motor vehicle bodies, in which an air flow is generated through an application zone of the line which carries away excess wet paint out of the application zone. It is known to separate entrained wet paint overspray from the exhaust air flow in a washing plant using a washing fluid. However, the known washing plants have the disadvantage, particularly in the case of air recirculation, that a high quantity of moisture is fed to the exhaust air flow, from which the wet paint overspray is separated, so that after separation of the wet paint overspray has been accomplished, the exhaust air flow must be subjected to an energy-intensive dehumidification. Moreover, a high expenditure is necessary for the treatment of the washing fluid laden with the wet paint overspray. The object forming the basis for the present invention is to provide a device of the aforementioned type, which allows a separation of the wet paint overspray from the exhaust air flow in a simple, reliable and energy-saving manner. This object is achieved according to the invention with a device with the features of the preamble of claim 1 in that the device comprises at least one separation device for separating the overspray from at least a part of the exhaust air flow, which has at least one regenerable surface filter, and that the flow path of the exhaust air flow from the application zone to the separation device has at least one constricted region, wherein the average flow direction of the exhaust air flow is substantially retained when passing through the constricted region. In this case, a regenerable surface filter is to be understood to mean a filter that has a filter surface, on which the wet paint overspray entrained by the exhaust air flow is deposited, and which can be cleaned, preferably during the continuous operation of the device, to remove the paint overspray deposited thereon. Such a regenerable surface filter is a "dry" separation device, in which no fluid is used to wash the overspray particles out of the exhaust air flow, instead filter elements are used to separate the overspray particles from the air flow. In this case, the cleaning of the regenerable surface filter can be achieved by means of a "dry" cleaning device, i.e. without using a cleaning fluid, or by means of a "wet" cleaning device, i.e. using a cleaning fluid. A "dry" separation device can also be provided with a "wet" cleaning device, so long as the separation of the overspray particles on the regenerable separation element is only conducted in a dry manner, i.e. without washing using a washing fluid. The entire separation of wet paint overspray from the exhaust air flow containing overspray particles is preferably conducted completely dry, i.e. without using a fluid for washing the overspray particles out of the exhaust air flow. Because a regenerable surface filter is used in the separation device, there is no necessity to provide a washing plant and the associated water treatment. As a result of this, the energy consumption of the separation device and also the space requirement of the device (because water treatment is unnecessary) are significantly reduced. The cleaning ability of the surface filter additionally assures a long service life of the filter even with large quantities of wet paint overspray being formed. By providing a constricted region in the flow path of the exhaust air flow from the application zone to the separation device, it is additionally possible to protect the regenerable surface filter from direct influences from the application zone. Because the average flow direction of the exhaust air flow is substantially retained during passage through the constricted region, it is possible to prevent a premature separation of wet paint overspray on boundary walls of the constricted region. In a preferred configuration of the device according to the invention it is provided that the constricted region is arranged below the application zone. If the application zone is arranged in a painting cabin, then the constricted region is preferably arranged within a vertical projection of the floor space of the painting cabin. In order to prevent wet paint overspray from already being deposited from the exhaust air flow on the boundary walls of the constricted region, it is advantageous if the extent of the constricted region in the flow direction of the exhaust air flow is shorter than approximately 6 m, preferably shorter than approximately 1 m, in particular shorter than approximately 0.5 m. If the application zone is arranged in a painting cabin with a longitudinal direction, then the constricted region preferably extends in the longitudinal direction of the painting cabin over substantially the entire length of the painting cabin. In this case, the constricted region can be subdivided in the longitudinal direction of the painting cabin into a plurality of constricted sub-areas. Alternatively to this, it can be provided that the constricted region is not subdivided in the longitudinal direction of the painting cabin. If the application zone is arranged in a painting cabin with a transverse direction, then it can be provided that the constricted region is subdivided in the transverse direction of the painting cabin into a plurality of constricted sub-areas. Alternatively to this, it can be provided that the constricted region is not subdivided in the transverse direction of the painting cabin. The entry of the exhaust air flow into the constricted region is preferably arranged above the at least one regenerable surface filter. If the application zone is arranged in a painting cabin with a transverse direction, then the smallest cross-section of the constricted region passed through by the exhaust air flow preferably has an extent in the transverse direction of the painting cabin, which at most amounts to approximately 20% of the extent of the painting cabin in the transverse direction of the painting cabin. In order to protect the at least one regenerable surface filter from damage, it is favourable if at least one shielding element is arranged vertically above the at least one regenerable surface filter, which prevents objects, dirt and/or paint particles from falling perpendicularly out of the application zone onto the regenerable surface filter. In this case, it can be provided that the at least one shielding element forms a boundary of the constricted region. In order to achieve favourable flow conditions in the flow path of the exhaust air flow, it is favourable if the device comprises at least one flow guide element, which directs at least a part of the exhaust air flow towards the constricted region. In this case, the flow guide element can have a flow guide surface, which is oriented substantially horizontally at least in sections. Alternatively to this, it can also be provided that the flow guide element has a flow guide surface inclined relative to the horizontal, at least in sections, preferably towards the constricted region. If the device has a base, which limits the flow path of the exhaust air flow downwards, then it can be provided that at least a part of the base is covered by a region separated from the region of the device passed through by the exhaust air flow. This results in a reduction in the base area that becomes fouled by wet paint overspray separated from the exhaust air flow before reaching the at least one regenerable surface filter. In this case, it can be provided that an upper boundary wall of the region separated from the region of the device passed through by the exhaust air flow forms at least a part of a flow guide element, which directs at least a part of the exhaust air flow towards the constricted region. If the application zone is arranged in a painting cabin and the device comprises at least one exhaust air duct, into which at least a part of the exhaust air flow enters after passing through the separation device, then a particularly space-saving structure of the device is achieved if the exhaust air duct is arranged within a vertical projection of the floor space of the painting cabin. In order to facilitate the cleaning of the regenerable surface filter, it is favourable if the at least one regenerable surface filter has a barrier layer comprising a precoat material, which prevents an agglutination of the filter surface. In order to generate the barrier layer of precoat material on the surface filter, it can be provided that the device has at least one precoat feeding means, which discharges a precoat material into the exhaust air flow. In this case, the discharge of precoat material into the exhaust air flow can occur continuously or at intervals. Lime, aluminium silicates, aluminium oxides, silicon oxides, powdered paint or the like can be considered for use as precoat materials, for example. In principle, any medium capable of absorbing the fluid content of the wet paint overspray is suitable as precoat material. In principle, the precoat feeding means can be arranged, for example, directly before the at least one regenerable surface filter. Moreover, it is possible to arrange the at least one precoat feeding means to directly adjoin the application zone, e.g. in the floor area of the painting cabin. However, it is particularly favourable if the at least one precoat feeding means is arranged at the constricted region of the flow path of the exhaust air flow. Particularly high flow rates prevail in the constricted region of the flow path of the exhaust air flow, and therefore a particularly good precoat distribution in the exhaust air flow is achieved by venturi turbulence by feeding the precoat material at this location. There is also the possibility of intermediate precoating during the precoating operation, wherein without previously cleaning the surface filter, new precoat material is applied to improve the subsequent cleaning behaviour of the surface filter. The at least one regenerable surface filter of the separation device can preferably be cleaned at intervals. Alternatively or additionally hereto, it can be provided that the at least one regenerable surface filter has a moist surface during operation of the device. The surface filter can be kept moist, for example, by rinsing or moistening agents such as demineralised water, butyl glycol or other solvents to facilitate cleaning of the surface filter. These moistening agents can be incorporated into the exhaust air flow at the same locations as the precoat material explained above. For a thorough cleaning of the filter surface of the surface filter, it is favourable if the surface of the at least one surface filter can be rinsed off continuously or at intervals. Alternatively or additionally hereto, it can be provided that the at least one regenerable surface filter can be cleaned by compressed air pulses. A particularly energy-saving operation of the painting line is enabled if the device has an air recirculation circuit, in which the exhaust air flow, from which the wet paint overspray has been separated, is fed at least partially again to the application zone. Claim 30 is directed towards a line for painting objects, in particular motor vehicle bodies, comprising at least one painting cabin and at least one device according to the invention for separating wet paint overspray from an exhaust air flow containing overspray particles. Further features and advantages of the invention are the subject of the following description and the representation of exemplary embodiments in the drawings. Figure 1 is a schematic vertical cross-section through a first embodiment of a painting cabin with a device arranged below it for separating wet paint overspray from an exhaust air flow containing overspray particles, which comprises two separation devices for separating the overspray from the exhaust air flow as well as two exhaust air ducts, which run laterally to the left or right adjacent to the boundary of the painting cabin, wherein a constricted region of the flow path of the exhaust air flow, which is defined by horizontally oriented flow guide elements, is provided between an application zone of the painting cabin and the separation devices; Figure 2 is a schematic side view of the line from Figure 1; Figure 3 is a schematic plan view from above onto the line from Figures 1 and 2; Figure 4 is a schematic perspective view of the line from Figures 1 to 3; Figure 5 is a schematic view of a recirculation circuit of the line from Figures 1 to 4; Figure 6 is a schematic perspective view of a regenerable surface filter of the line from Figures 1 to 5; Figure 7 is a schematic view in longitudinal section through the surface filter from Figure 6, which illustrates a cleaning process of the surface filter; Figure 8 is a schematic perspective view of an alternative embodiment of a regenerable surface filter; Figure 9 is a schematic cross-section through the surface filter from Figure 8, which illustrates a cleaning process of the surface filter; Figure 10 is a schematic plan view from above onto the surface filter from Figures 8 and 9; Figure 11 is a schematic cross-section through a second embodiment of a painting cabin with a device arranged below it for separating wet paint overspray from an exhaust air flow containing overspray particles, which comprises two separation devices for separating the overspray from the exhaust air flow and two exhaust air ducts, which run laterally to the left or right adjacent to the boundary of the painting cabin, wherein a constricted region of the flow path of the exhaust air flow, which is defined by flow guide elements inclined relative to the horizontal, is provided between an application zone of the painting cabin and the separation devices; Figure 12 is a schematic side view of the line from Figure 11; Figure 13 is a schematic plan view from above onto the line from Figures 11 and 12; Figure 14 is a schematic perspective representation of the line from Figures 11 to 13; Figure 15 is a schematic cross-section through a third embodiment of a painting cabin with a device arranged below it for separating wet paint overspray from an exhaust air flow containing overspray particles, which comprises two separation devices for separating the overspray from the exhaust air flow and two exhaust air ducts, which run laterally to the left or right adjacent to the boundary of the painting cabin, wherein a constricted region of the flow path of the exhaust air flow in the form of a shaft extending in vertical direction is provided between an application zone of the painting cabin and the separation devices; Figure 16 is a schematic side view of the line from Figure 15; Figure 17 is a schematic plan view from above onto the line from Figures 15 and 16; Figure 18 is a schematic perspective representation of the line from Figures 15 to 17; Figure 19 is a schematic cross-section through a fourth embodiment of a painting cabin with a device arranged below it for separating wet paint overspray from an exhaust air flow containing overspray particles, which comprises a separation device for separating the overspray from the exhaust air flow and an exhaust air duct arranged within a vertical projection of the floor space of the painting cabin; Figure 20 is a schematic side view of the line from Figure 19; Figure 21 is a schematic plan view from above onto the line from Figures 19 and 20; and Figure 22 is a schematic perspective representation of the line from Figures 19 to 21. Identical or functionally equivalent elements have been given the same references in all figures. A line for spray painting motor vehicle bodies 102 shown in Figures 1 to 7 and given the overall reference 100 comprises a transport device 104 (shown purely schematically), by means of which the motor vehicle bodies 102 can be moved in a transport direction 106 through an application zone 108 of a painting cabin given the overall reference 110. The transport device 104 can be configured, for example, as an inverted circular conveyor or also as an inverted monorail conveyor. In particular, the transport device 104 can be configured in two parts and - as can best be seen from Figures 1, 3 and 4 - comprise two transport tracks 104a and 104b extending parallel to the transport direction 106, which are spaced from one another in a horizontal direction perpendicular to the transport direction 106. The application zone 108 is the interior of the painting cabin 110, which in its horizontal transverse direction 112 running perpendicular to the transport direction 106, which corresponds to the longitudinal direction of the painting cabin 110, is defined on both sides of the transport device 104 by a respective cabin wall 114. Spray painting devices 116 (see Figures 1 to 4), e.g. in the form of painting robots, are arranged in the painting cabin 110 on both sides of the transport device 104. An air flow, which passes through the application zone 108 substantially vertically downwards from above, as indicated by arrows 119 in Figure 1, is generated by means of an air flow generating means 118 shown schematically in Figure 5. This air flow takes up paint overspray in the form of overspray particles in the application zone 108. The term "particles" in this case covers both solid and liquid particles, in particular droplets. If a wet paint is used for painting in the line 100, then the wet paint overspray consists of paint droplets. The largest dimension of most of the overspray particles is in the range of approximately 1 µm to approximately 100µm.The exhaust air flow represented by arrows 120 leaves the painting cabin 110 through a cabin floor 122, which is formed by air-permeable gratings 124. The line 100 additionally comprises at least one device, given the overall reference 126 and only one device 126 shown in the figures, for separating wet paint overspray from the air flow 120, which is arranged below the application zone 108. The device 126 comprises a substantially cuboidal flow chamber 128, which extends in the transport direction 106 over the entire length of the painting cabin 110 and beyond, and in the transverse direction 112 of the painting cabin 110 is defined by vertical side walls 130, which are substantially in alignment with the lateral cabin walls 114 of the painting cabin 110, so that the flow chamber 128 has substantially the same horizontal cross-sectional area as the painting cabin 110 and is largely arranged completely within the vertical projection of the floor space of the painting cabin 110. The flow chamber 128 is subdivided into an upper section 136 and a lower section 138 by flow guide elements 132, which in this exemplary embodiment are configured as substantially horizontally oriented flow baffle plates 134. The upper section 136 and the lower section 138 of the flow chamber 128 are connected to one another by means of a constricted region 140, which is in the form of a gap 142 between the opposing free edges of the flow guide elements 132 and forms a narrow point in the flow path of the exhaust air flow 120 through the flow chamber 128. The upper sides of the flow guide elements 132 respectively form a flow guide surface 135, which directs the exhaust air flow 120 towards the constricted region 140. A precoat feeding means 144, which discharges a precoat material continuously or at intervals into the exhaust air flow 120, is arranged at the constricted region 140 of the flow path. Alternatively, the at least one precoat feeding means (144) may be arranged in the floor region of the painting cabin (110). The precoat feeding means 144 can be configured, for example, as a precoat spray nozzle, which discharges the precoat material in the form of a spray mist into the exhaust air flow 120. The arrangement of the precoat feeding means 144 at the constricted region 140 of the flow path of the exhaust air flow 120 provides the advantage that, because of the increased flow rate of the exhaust air flow 120 and because of the small flow cross-section, turbulences occur in the exhaust air flow, which assure turbulence of the precoat material in the exhaust air flow 120 and thus ensure a particularly favourable distribution of the precoat material in the exhaust air flow 120. The precoat feeding means 144 is connected to a precoat feed pipe (not shown), which feeds the precoat material in flowable state from a precoat storage container (not shown) by means of a precoat feed pump (not shown). In principle, any medium that is able to absorb the fluid content of the wet paint overspray can be used as precoat material. In particular, lime, aluminium silicates, aluminium oxides, silicon oxides, powdered paint or similar may be considered as precoat materials. Aqueous dispersions of the said materials are used, for example, to make the precoat material flowable and sprayable. If the filter arranged after the precoat feeding means 144 is not be precoated, but merely moistened, it is also possible to only incorporate a moistening agent into the exhaust air flow 120 by means of the precoat feeding means 144. For example, demineralised water, butyl glycol or other solvents can be considered in particular as such moistening agents. A separation device 145 for separating wet paint overspray from the exhaust air flow 120 is respectively provided on both sides of the constricted region 140 in the lower section 138 of the flow chamber 128. The separation devices 145 respectively comprise a plurality of regenerable surface filters 146 arranged spaced from one another in the transport direction 106 on both opposing vertical side walls 130 of the flow chamber 128, said surface filters projecting into the lower section 138 of the flow chamber 128 with their filter elements 148 (see in particular Figures 1, 2 and 4). One of these regenerable surface filters 146 is shown in detail in Figures 6 and 7. Each of the regenerable surface filters 146 comprises a hollow base body 150, on which a plurality of filter elements 154, e.g. four in each case, are held. The filter elements 154 are substantially plate-shaped, for example, and preferably have a serrated cross-section, as evident from Figure 6, to increase the available filter surface 156. The filter elements 154 can be configured, for example, as plates of sintered polyethylene, which are provided with a membrane of polytetrafluoroethylene (PTFE) on their outer face. Alternatively or additionally hereto, it can also be provided that the filter elements 154 are formed from a nonwoven fabric with a PTFE coating. The coating of PTFE respectively serves to increase the filtration class of the surface filter 146 (i.e. decrease its permeability) and moreover to prevent the wet paint overspray separated from the exhaust air flow 120 from adhering permanently. Both the base material of the filter elements 154 and their PTFE coating have a porosity, so that the exhaust air can pass through the pores into the inner area 176 of the respective filter element 154. In order to prevent the agglutination of the filter surface 156, this is additionally provided with a barrier layer of the precoat material discharged into the exhaust air flow. This barrier layer is formed during operation of the device 126 simply by deposition of the precoat material discharged into the exhaust air flow 120 on the filter surface 156. The amongst of the amount of precoat material discharged into the exhaust air flow 120 is preferably so regulated that the thickness of the barrier layer of precoat material on the filter elements 154 of the regenerable surface filters 146 lies in the range of approximately 150 µm to 200 µm, for example. The exhaust air flow 120 sweeps over the filter surfaces 156 of the filter elements 154 of the regenerable surface filter 146, wherein both the entrained precoat material and the entrained wet paint overspray are deposited on the filter surface 156, and passes through the porous filter surfaces 156 into the inner areas 176 of the filter elements 154, which are connected to the cavity inside the base body 150. The cleaned exhaust air flow 120 thus passes through the base body 150 respectively into an exhaust air pipe 158, which runs from the respective regenerable surface filter 146 to an exhaust air duct 160 running parallel to the transport direction 106 laterally next to a vertical side wall 130 of the flow chamber 128. As may be seen from the schematic representation in Figure 5, the cleaned exhaust air with the wet paint overspray removed passes out of the two exhaust air ducts 160 at least partially back to the air flow generating means 118, which feeds the cleaned exhaust air through a feed pipe 162 to the application zone 108 in the painting cabin 110 again. Another part of the cleaned exhaust air flow is discharged to the surrounding area through a discharge nozzle 164 in an exhaust air pipe 166. This part of the exhaust air flow discharged to the surrounding area is replaced by fresh air, which is fed to the air flow generating means 118 through a free air feed pipe 168. The bulk of the air passed through the application zone 108 is therefore directed in an air recirculation circuit 170, which comprises the air flow generating means 118, the feed pipe 162, the application zone 108, the flow chamber 128 and the exhaust air ducts 160, as a result of which constant heating of freshly supplied additional air is avoided and the energy costs are thus significantly reduced. Since the separation of the wet paint overspray from the exhaust air flow 120 by means of the regenerable surface filters 146 is conducted dry, i.e. without washing with cleaning fluid, the air directed in the recirculation circuit 170 is not moistened during the separation of the wet paint overspray, and therefore no devices for moistening the air directed in the recirculation circuit 170 are required at all. Moreover, no devices are necessary for separating wet paint overspray from a washing-cleaning fluid. The regenerable surface filters 146 are cleaned by compressed air pulses at specific time intervals, when the degree to which they are laden with wet paint overspray has reached a predetermined value. This cleaning can be performed, for example, once per work shift, i.e. twice to three times per working day. The necessary compressed air pulses are generated by means of a compressed air storage unit 172, which is arranged on the base body 150 of the respective regenerable surface filter 146 and is capable of discharging compressed air pulses to compressed air pipes 174, which run inside the respective base body 150 and lead from the compressed air storage unit 172 into the inner areas 176 of the filter elements 154. From the inner areas 176 of the filter elements 154, the compressed air pulses pass through the porous filter surfaces 156 into the outer area of the filter elements 154, wherein the barrier layer of precoat material formed on the filter surfaces 156 and the wet paint overspray deposited thereon is detached from the filter surfaces 156, so that the filter surfaces 156 are returned to their original cleaned state. The flow direction of the compressed air through a regenerable surface filter 146 during cleaning is represented by arrows 177 in Figure 7. The store of compressed air in the compressed air storage units 172 is supplemented from a compressed air supply present on the construction side through compressed air feed pipes (not shown). Alternatively or additionally to a cleaning by means of compressed air pulses, it can also be provided that the regenerable surface filters 146 are rinsed off by means of a suitable rinsing device at predetermined intervals in order to remove the wet paint overspray deposited on the filter surfaces 156. As may best be seen from Figures 1 and 2, the material cleaned from the filter surfaces 156 of the regenerable surface filter 146 passes onto a collection belt 178, which is arranged on the base of the flow chamber 128 and is configured, for example, as an endless belt rotating around a driven roller 180 and an idle return roller 182. The driven roller 180 is set in rotation by means of a drive motor 184 to set the collection belt 178 in motion in the transport direction 106. In this way, the material consisting of precoat material and separated wet paint overspray that is passed from the regenerate surface filters 146 onto the surface of the collection belt 178 is transported by means of the collection belt 178 to a separation device (not shown), by means of which this material is detached from the collection belt 178 (e.g. by means of stripping), collected and possibly passed on for further use. The collection belt 178 also takes up part of the wet paint overspray, which passes directly from the exhaust air flow 120 onto the collection belt 178, before the exhaust air flow 120 reaches the regenerable surface filters 146. An alternative configuration of the regenerable surface filters 146 that can be used in the device 126 is shown in Figures 8 to 10. Instead of a plurality of vertically oriented plate-shaped filter elements arranged adjacent to one another, the regenerable surface filter shown in Figures 8 to 10 comprises a substantially cylindrical filter element 154', which likewise has a serrated filter surface 156 viewed in cross-section to increase the available filter surface 156. In addition to the generation of compressed air pulses, in this embodiment a rinsing fluid ring conduit 186 is provided for cleaning the regenerable surface filter 146. This ring conduit sprays a rinsing fluid against the filter surface 156 of the filter element 154' through rinsing fluid outlets provided on the radial inside of the rinsing fluid ring conduit 186, so that the rinsing fluid detaches the barrier layer and the wet paint overspray deposited thereon from the filter surface 156 and conveys it onto the collection belt 178. A second embodiment of a line 100 for painting motor vehicle bodies 102 shown in Figures 11 to 14 differs from the first embodiment described above in that in this second embodiment the flow guide elements 132, which separate the lower section 138 from the upper section 136 of the flow chamber 128 of the device 126 for separating wet paint overspray, are not oriented substantially horizontally, as in the case of the first embodiment, but are inclined relative to the horizontal such that they slope down towards the constricted region 140, as best shown in Figure 11. The angle of inclination relative to the horizontal preferably amounts to approximately 5° to approximately 30°. As a result of this inclination of the flow guide elements 132 and thus of the flow guide surfaces 135 on their upper side, a funnel-shaped structure of the lower region of the upper section 136 of the flow chamber 128 is achieved, by means of which the air flow towards the constricted region 140 is rendered more uniform and the extent of the turbulences on the upper side of the flow guide elements 132 is reduced. In this way, a smaller proportion of wet paint overspray is already deposited on the flow guide surfaces 135 before the exhaust air flow 120 reaches the lower section 138 of the flow chamber 128. In addition, the flow guide elements 132 are arranged slightly higher inside the flow chamber 128 in the second embodiment than in the first embodiment. Otherwise, the second embodiment of a line 100 for painting motor vehicle bodies 102 shown in Figures 11 to 14 has the same structure and function as the first embodiment shown in Figures 1 to 10, and on this basis reference is made to the above description thereof. A third embodiment of a line 100 for painting motor vehicle bodies 102 shown in Figures 15 to 18 differs from the second embodiment described above in that the constricted region 140 is not formed merely by a gap 142 between the opposing edges of the flow guide elements 132, but comprises an exhaust air shaft 188, which extends vertically downwards from the opposing edges of the flow guide elements 132 and is defined on its two longitudinal sides by vertical shaft side walls 190 extending in the transport direction 106. Configured between the lower edge of each shaft side wall 190 and the upper side of the collection belt 178 on the base of the flow chamber 128 is a respective vertical gap 192, through which the exhaust air flow 120 exits from the constricted region 140 into the lower section 138 of the flow chamber 128, wherein in this embodiment the lower section 138 of the flow chamber 128 is subdivided into two sub-areas 138a, 138b respectively arranged on a side of the exhaust air shaft 188. Moreover, in this embodiment the filter elements 154 of the regenerable surface filters 146 do not extend into the lower section 138 of the flow chamber 128 in a substantially horizontal direction, but rather are inclined relative to the horizontal, i.e. preferably by approximately the same angle as the flow guide surfaces 135 of the flow guide elements 132. This angle of inclination relative to the horizontal preferably lies in the range of approximately 5° to approximately 30°. Because of this inclination of the filter elements 154 of the regenerable surface filters 146 relative to the horizontal, the base bodies 150 of the regenerable surface filters 146 and the upper regions of the side walls 130 of the lower section 138 of the flow chamber 128 are likewise not oriented vertically, but inclined relative to the vertical by an acute angle, which corresponds to the angle of inclination of the filter elements 154 and the flow guide surfaces 135 relative to the horizontal. In this embodiment, the regenerable surface filters 146 are particularly well protected from objects falling out of the application zone 108. Moreover, the upper section 136 and the lower section 138 of the flow chamber 128 are disconnected from one another with respect to flow by the exhaust air shaft 188, so that the exhaust air flow in the lower section 138 of the flow chamber 128 is largely independent of the flow conditions in the upper section 136 of the flow chamber 128. Since in this embodiment two gaps 192 are present, through which the exhaust air flow 120 enters the lower section 138 of the flow chamber 128, two precoat feeding means 144 are also provided, which are arranged respectively adjacent to one of the vertical gaps 192 at the lower end of one of the shaft side walls 190. Otherwise, the third embodiment of a line 100 for painting motor vehicle bodies 102 shown in Figures 15 to 18 has the same structure and function as the second embodiment shown in Figures 11 to 14, and on this basis reference is made to the above description thereof. A fourth embodiment of a line 100 for spray painting motor vehicle bodies 102 shown in Figures 19 to 22 differs from the first embodiment described above in that the device 126 for separating wet paint overspray from the exhaust air flow 120 is not configured symmetrically to the longitudinal central plane 194 of the painting cabin 110, but asymmetrically to this longitudinal central plane 194. In particular, the regenerable surface filters 146 in this embodiment are only arranged on one side of the longitudinal central plane 194 (namely on the side shown on the left in Figure 19). In this embodiment only a single exhaust air duct 160 is provided, which, moreover, is not arranged laterally outside the side wall 130 of the flow chamber 128, but instead is integrated into the flow chamber 128 and is arranged directly below one of the flow guide elements 132, so that the respective flow guide element 132 forms an upper boundary of the exhaust air duct 160. The regenerable surface filters 146 in this embodiment are not connected to the exhaust air duct 160 by means of exhaust air pipes 158, but are arranged directly on a lower boundary wall 196 of the exhaust air duct 160, wherein the filter elements 154 of the regenerable surface filters 146 hang down in a substantially vertical direction from the lower boundary wall 196 of the exhaust air duct 160 into the lower section 138 of the flow chamber 128. A particularly efficient cleaning of the regenerable surface filters 146 is possible as a result of this hanging arrangement. The side of the lower section 138 of the flow chamber 128 opposite the side of the flow chamber 128 provided with the regenerable surface filters 146 is separated by means of a vertical dividing wall 198 from the region of the lower section 138 of the flow chamber 128 passed through by the exhaust air flow 120. This separated region 200 is defined upwards by one of the flow guide elements 132 and extends downwards as far as the base 202 of the flow chamber 128. This region 200 separated from the throughflow region of the flow chamber 128 can be used, for example, to receive auxiliary units such as fans, storage containers, pumps or similar. Alternatively or additionally hereto, it is possible to use the separated region 200 as an air duct, e.g. as an additional exhaust air duct, fresh air supply duct or exhaust air discharge duct. The throughflow region of the lower section 138 of the flow chamber 128 is defined to the bottom by the collection belt 178. It can be seen in particular from Figure 20 that in the region of its idle return roller 182 the collection belt 178 is cleaned by means of a stripper 204 to remove the material containing precoat material and deposited wet paint overspray collected on the surface of the collection belt 178, wherein the material stripped from the collection belt 178 passes into a mobile collecting tank 206. When a predetermined maximum filling level is reached in the mobile collecting tank 206, the mobile collecting tank 206 is replaced by an empty mobile collecting tank 206, and the filled mobile collecting tank 206 is driven to a collection and further processing station. Since all the components of the device 126 for separating wet paint overspray are arranged within the vertical projection of the floor space of the painting cabin 110 in the fourth embodiment shown in Figures 19 to 22, this embodiment has a particularly compact structure and is particularly suitable for confined space conditions. Otherwise, the fourth embodiment shown in Figures 19 to 22 has the same structure and function as the first embodiment shown in Figures 1 to 10, and on this basis reference is made to the above description thereof. WE CLAIM:- 1. Installation for painting objects, comprising at least one painting cabin (110) and at least one device (126) for separating wet paint overspray from an exhaust air flow (120) containing overspray particles, wherein the overspray particles pass into the exhaust air flow (120) in an application zone (108) of the painting cabin (110), wherein the device (126) for separating wet paint overspray comprises at least one separation device (145) for separating the overspray from at least a part of the exhaust air flow (120), which has at least one regenerable surface filter (146), wherein the flow path of the exhaust air flow (120) from the application zone (108) to the separation device (145) has at least one constricted region (140), and wherein the device (126) for separating wet paint overspray is configured asymmetrically to a longitudinal central plane (194) of the painting cabin (110), wherein the regenerable surface filters (146) are arranged only on one side of the longitudinal central plane (194). 2. Installation according to Claim 1, characterised in that the constricted region (140) is arranged below the application zone (108). 3. Installation according to Claim 2, characterised in that the constricted region (140) is arranged within a vertical projection of the floor space of the painting cabin (110). 4. Installation according to one of Claims 1 to 3, characterised in that the extent of the constricted region (140) in the flow direction of the exhaust air flow (120) is shorter than 6 m. 5. Installation according to Claim 4, characterised in that the extent of the constricted region (140) in the flow direction of the exhaust air flow (120) is shorter than 1 m. 6. Installation according to Claim 5, characterised in that the extent of the constricted region (140) in the flow direction of the exhaust air flow (120) is shorter than 0.5 m. 7. Installation according to any of Claims 1 to 6, characterised in that the application zone (108) is arranged in a painting cabin (110) with a longitudinal direction (106), and that the constricted region (140) is subdivided in the longitudinal direction (106) of the painting cabin (110) into a plurality of constricted sub-regions. 8. Installation according to one of Claims 1 to 7, characterised in that the entry of the exhaust air flow (120) into the constricted region (140) is arranged above the at least one regenerable surface filter (146). 9. Installation according to any of Claims 1 to 8, characterised in that the application zone (108) is arranged in a painting cabin (110) with a transverse direction (112), and that the smallest cross-section of the constricted region (140) passed through by the exhaust air flow (120) has an extent in the transverse direction (112) of the painting cabin (110), which at most amounts to 20% of the extent of the painting cabin (110) in the transverse direction (112) of the painting cabin (110). 10. Installation according to any of Claims 1 to 9, characterised in that arranged vertically above the at least one regenerable surface filter (146) is at least one shielding element (132), which is oriented substantially horizontally at least in sections, which prevents objects, dirt and/or paint particles from falling vertically out of the application zone (108) onto the regenerable surface filter (146), and which also serves as a flow guide element which directs at least a part of the exhaust air flow (120) towards the constricted region (140). 11. An installation according to one of Claims 1 to 10, characterised in that the at least one device (126) comprises a flow chamber (128) and that a side of the flow chamber (128) lying opposite to a side of the flow chamber (128) which is provided with the regenerable surface filters (146) is separated by a dividing wall (198) from a region of the flow chamber (128) which is passed through by the exhaust air flow (120), so that a separated region (200) is formed. 12. An installation according to Claim 11, characterised in that the separated region (200) receives auxiliary units such as fans, storage containers and/or pumps and/or an exhaust air duct. 13. An installation according to Claim 11 or 12, characterised in that the flow chamber (128) including the separated region (200) is arranged substantially within a vertical projection of the floor space of the painting cabin (110). 14. An installation according to one of Claims 11 to 13, characterised in that the separated region (200) covers at least a part of a base (202) of the device (126) and is defined upwards by a flow guide element and laterally bordered by the dividing wall (198). 15. An installation according to one of Claims 1 to 14, characterised in that the device (126) comprises a flow chamber (128) which is subdivided into an upper section (136) and a lower section (138) by flow guide elements, wherein the upper section (136) and the lower section (138) are connected to one another by the constricted region (140) and the constricted region (140) comprises an exhaust air shaft which is defined by shaft side walls extending in a transport direction (106) of the objects. 16. An installation according to one of Claims 1 to 15, characterised in that the device (126) comprises at least one exhaust air duct (160), into which at least a part of the exhaust air flow (120) enters after passing through the separation device (145), wherein the exhaust air duct (160) is arranged within a vertical projection of the floor space of the painting cabin (110). 17. An installation according to one of Claims 1 to 16, characterised in that the at least one regenerable surface filter (146) has a barrier layer comprising a precoat material, which prevents an agglutination of the filter surface (156). 18. An installation according to Claim 17, characterised in that a collecting tank (206) for precoat material and deposited wet paint overspray is arranged vertically below the regenerable surface filter (146) and that precoat material and wet paint overspray that are cleaned off the regenerable surface filter (146) at intervals are collected in the collecting tank (206). 19. Installation according to one of Claims 17 or 18, characterised in that the installation comprises at least one precoat feeding means (144), which discharges a precoat material, into the exhaust air flow (120). 20. Installation according to Claim 19, characterised in that the precoat material comprises lime, an aluminium silicate, an aluminium oxide, a silicon oxide or powdered paint. 21. Installation according to one of Claims 1 to 20, characterised in that the at least one regenerable surface filter (146) is configured to be cleaned at intervals. 22. Installation according to one of Claims 1 to 21, characterised in that the at least one regenerable surface filter (146) has a moist surface during operation of the device (126). 23. Installation according to Claim 22, characterised in that the filter surface of the at least one regenerable surface filter (146) is configured to be rinsed off continuously or at intervals. 24. Installation according to one of Claims 1 to 23, characterised in that the device (126) has an air recirculation circuit (170), in which the exhaust air flow (120), from which the wet paint overspray has been separated, is fed, at least partially, to the application zone (108) in the painting cabin (110) again. 25. Installation according to one of Claims 1 to 24, characterised in that the at least one regenerable surface filter (146) is arranged within a vertical projection of the floor space of the painting cabin. 26. Installation according to one of Claims 1 to 25, characterised in that the objects to be painted are motor vehicle bodies (102).

Full Text

Device for Separating Wet Paint Overspray
The present invention relates to a device for separating wet paint overspray from an exhaust air flow containing overspray particles, wherein the overspray particles pass into the exhaust air flow in an application zone of a painting line.
Such devices are used in assemblies for painting workpieces, in particular for spray painting motor vehicle bodies, in which an air flow is generated through an application zone of the line which carries away excess wet paint out of the application zone.
It is known to separate entrained wet paint overspray from the exhaust air flow in a washing plant using a washing fluid.
However, the known washing plants have the disadvantage, particularly in the case of air recirculation, that a high quantity of moisture is fed to the exhaust air flow, from which the wet paint overspray is separated, so that after separation of the wet paint overspray has been accomplished, the exhaust air flow must be subjected to an energy-intensive dehumidification.
Moreover, a high expenditure is necessary for the treatment of the washing fluid laden with the wet paint overspray.
The object forming the basis for the present invention is to provide a device of the aforementioned type, which allows a separation of the wet paint overspray from the exhaust air flow in a simple, reliable and energy-saving manner.
This object is achieved according to the invention with a device with the features of the preamble of claim 1 in that the device comprises at least one separation device for separating the overspray from at least a part of the exhaust air flow, which has at least one regenerable surface filter, and that the flow path of the exhaust air flow from the application zone to the
separation device has at least one constricted region, wherein the average flow direction of the exhaust air flow is substantially retained when passing through the constricted region.
In this case, a regenerable surface filter is to be understood to mean a filter that has a filter surface, on which the wet paint overspray entrained by the exhaust air flow is deposited, and which can be cleaned, preferably during the continuous operation of the device, to remove the paint overspray deposited thereon.
Such a regenerable surface filter is a "dry" separation device, in which no fluid is used to wash the overspray particles out of the exhaust air flow, instead filter elements are used to separate the overspray particles from the air flow.
In this case, the cleaning of the regenerable surface filter can be achieved by means of a "dry" cleaning device, i.e. without using a cleaning fluid, or by means of a "wet" cleaning device, i.e. using a cleaning fluid.
A "dry" separation device can also be provided with a "wet" cleaning device, so long as the separation of the overspray particles on the regenerable separation element is only conducted in a dry manner, i.e. without washing using a washing fluid.
The entire separation of wet paint overspray from the exhaust air flow containing overspray particles is preferably conducted completely dry, i.e. without using a fluid for washing the overspray particles out of the exhaust air flow.
Because a regenerable surface filter is used in the separation device, there is no necessity to provide a washing plant and the associated water treatment. As a result of this, the energy consumption of the separation device and also the space requirement of the device (because water treatment is unnecessary) are significantly reduced.
The cleaning ability of the surface filter additionally assures a long service life of the filter even with large quantities of wet paint overspray being formed.
By providing a constricted region in the flow path of the exhaust air flow from the application zone to the separation device, it is additionally possible to protect the regenerable surface filter from direct influences from the application zone.
Because the average flow direction of the exhaust air flow is substantially retained during passage through the constricted region, it is possible to prevent a premature separation of wet paint overspray on boundary walls of the constricted region.
In a preferred configuration of the device according to the invention it is provided that the constricted region is arranged below the application zone.
If the application zone is arranged in a painting cabin, then the constricted region is preferably arranged within a vertical projection of the floor space of the painting cabin.
In order to prevent wet paint overspray from already being deposited from the exhaust air flow on the boundary walls of the constricted region, it is advantageous if the extent of the constricted region in the flow direction of the exhaust air flow is shorter than approximately 6 m, preferably shorter than approximately 1 m, in particular shorter than approximately 0.5 m.
If the application zone is arranged in a painting cabin with a longitudinal direction, then the constricted region preferably extends in the longitudinal direction of the painting cabin over substantially the entire length of the painting cabin.
In this case, the constricted region can be subdivided in the longitudinal direction of the painting cabin into a plurality of constricted sub-areas.
Alternatively to this, it can be provided that the constricted region is not subdivided in the longitudinal direction of the painting cabin.
If the application zone is arranged in a painting cabin with a transverse direction, then it can be provided that the constricted region is subdivided in the transverse direction of the painting cabin into a plurality of constricted sub-areas.
Alternatively to this, it can be provided that the constricted region is not subdivided in the transverse direction of the painting cabin.
The entry of the exhaust air flow into the constricted region is preferably arranged above the at least one regenerable surface filter.
If the application zone is arranged in a painting cabin with a transverse direction, then the smallest cross-section of the constricted region passed through by the exhaust air flow preferably has an extent in the transverse direction of the painting cabin, which at most amounts to approximately 20% of the extent of the painting cabin in the transverse direction of the painting cabin.
In order to protect the at least one regenerable surface filter from damage, it is favourable if at least one shielding element is arranged vertically above the at least one regenerable surface filter, which prevents objects, dirt and/or paint particles from falling perpendicularly out of the application zone onto the regenerable surface filter.
In this case, it can be provided that the at least one shielding element forms a boundary of the constricted region.
In order to achieve favourable flow conditions in the flow path of the exhaust air flow, it is favourable if the device comprises at least one flow
guide element, which directs at least a part of the exhaust air flow towards the constricted region.
In this case, the flow guide element can have a flow guide surface, which is oriented substantially horizontally at least in sections.
Alternatively to this, it can also be provided that the flow guide element has a flow guide surface inclined relative to the horizontal, at least in sections, preferably towards the constricted region.
If the device has a base, which limits the flow path of the exhaust air flow downwards, then it can be provided that at least a part of the base is covered by a region separated from the region of the device passed through by the exhaust air flow. This results in a reduction in the base area that becomes fouled by wet paint overspray separated from the exhaust air flow before reaching the at least one regenerable surface filter. In this case, it can be provided that an upper boundary wall of the region separated from the region of the device passed through by the exhaust air flow forms at least a part of a flow guide element, which directs at least a part of the exhaust air flow towards the constricted region.
If the application zone is arranged in a painting cabin and the device comprises at least one exhaust air duct, into which at least a part of the exhaust air flow enters after passing through the separation device, then a particularly space-saving structure of the device is achieved if the exhaust air duct is arranged within a vertical projection of the floor space of the painting cabin.
In order to facilitate the cleaning of the regenerable surface filter, it is favourable if the at least one regenerable surface filter has a barrier layer comprising a precoat material, which prevents an agglutination of the filter surface.
In order to generate the barrier layer of precoat material on the surface filter, it can be provided that the device has at least one precoat feeding means, which discharges a precoat material into the exhaust air flow.
In this case, the discharge of precoat material into the exhaust air flow can occur continuously or at intervals.
Lime, aluminium silicates, aluminium oxides, silicon oxides, powdered paint or the like can be considered for use as precoat materials, for example.
In principle, any medium capable of absorbing the fluid content of the wet paint overspray is suitable as precoat material.
In principle, the precoat feeding means can be arranged, for example, directly before the at least one regenerable surface filter.
Moreover, it is possible to arrange the at least one precoat feeding means to directly adjoin the application zone, e.g. in the floor area of the painting cabin.
However, it is particularly favourable if the at least one precoat feeding means is arranged at the constricted region of the flow path of the exhaust air flow. Particularly high flow rates prevail in the constricted region of the flow path of the exhaust air flow, and therefore a particularly good precoat distribution in the exhaust air flow is achieved by venturi turbulence by feeding the precoat material at this location.
There is also the possibility of intermediate precoating during the precoating operation, wherein without previously cleaning the surface filter, new precoat material is applied to improve the subsequent cleaning behaviour of the surface filter.
The at least one regenerable surface filter of the separation device can preferably be cleaned at intervals.
Alternatively or additionally hereto, it can be provided that the at least one regenerable surface filter has a moist surface during operation of the device.
The surface filter can be kept moist, for example, by rinsing or moistening agents such as demineralised water, butyl glycol or other solvents to facilitate cleaning of the surface filter.
These moistening agents can be incorporated into the exhaust air flow at the same locations as the precoat material explained above.
For a thorough cleaning of the filter surface of the surface filter, it is favourable if the surface of the at least one surface filter can be rinsed off continuously or at intervals.
Alternatively or additionally hereto, it can be provided that the at least one regenerable surface filter can be cleaned by compressed air pulses.
A particularly energy-saving operation of the painting line is enabled if the device has an air recirculation circuit, in which the exhaust air flow, from which the wet paint overspray has been separated, is fed at least partially again to the application zone.
Claim 30 is directed towards a line for painting objects, in particular motor vehicle bodies, comprising at least one painting cabin and at least one device according to the invention for separating wet paint overspray from an exhaust air flow containing overspray particles.
Further features and advantages of the invention are the subject of the following description and the representation of exemplary embodiments in the drawings.
Figure 1 is a schematic vertical cross-section through a first
embodiment of a painting cabin with a device arranged below
it for separating wet paint overspray from an exhaust air flow containing overspray particles, which comprises two separation devices for separating the overspray from the exhaust air flow as well as two exhaust air ducts, which run laterally to the left or right adjacent to the boundary of the painting cabin, wherein a constricted region of the flow path of the exhaust air flow, which is defined by horizontally oriented flow guide elements, is provided between an application zone of the painting cabin and the separation devices;
Figure 2 is a schematic side view of the line from Figure 1;
Figure 3 is a schematic plan view from above onto the line from Figures 1 and 2;
Figure 4 is a schematic perspective view of the line from Figures 1 to 3;
Figure 5 is a schematic view of a recirculation circuit of the line from Figures 1 to 4;
Figure 6 is a schematic perspective view of a regenerable surface filter of the line from Figures 1 to 5;
Figure 7 is a schematic view in longitudinal section through the surface filter from Figure 6, which illustrates a cleaning process of the surface filter;
Figure 8 is a schematic perspective view of an alternative embodiment of a regenerable surface filter;
Figure 9 is a schematic cross-section through the surface filter from Figure 8, which illustrates a cleaning process of the surface filter;
Figure 10 is a schematic plan view from above onto the surface filter from Figures 8 and 9;
Figure 11 is a schematic cross-section through a second embodiment of a painting cabin with a device arranged below it for separating wet paint overspray from an exhaust air flow containing overspray particles, which comprises two separation devices for separating the overspray from the exhaust air flow and two exhaust air ducts, which run laterally to the left or right adjacent to the boundary of the painting cabin, wherein a constricted region of the flow path of the exhaust air flow, which is defined by flow guide elements inclined relative to the horizontal, is provided between an application zone of the painting cabin and the separation devices;
Figure 12 is a schematic side view of the line from Figure 11;
Figure 13 is a schematic plan view from above onto the line from Figures 11 and 12;
Figure 14 is a schematic perspective representation of the line from Figures 11 to 13;
Figure 15 is a schematic cross-section through a third embodiment of a painting cabin with a device arranged below it for separating wet paint overspray from an exhaust air flow containing overspray particles, which comprises two separation devices for separating the overspray from the exhaust air flow and two exhaust air ducts, which run laterally to the left or right adjacent to the boundary of the painting cabin, wherein a constricted region of the flow path of the exhaust air flow in the form of a shaft extending in vertical direction is provided between an application zone of the painting cabin and the separation devices;
Figure 16 is a schematic side view of the line from Figure 15;
Figure 17 is a schematic plan view from above onto the line from Figures 15 and 16;
Figure 18 is a schematic perspective representation of the line from Figures 15 to 17;
Figure 19 is a schematic cross-section through a fourth embodiment of a painting cabin with a device arranged below it for separating wet paint overspray from an exhaust air flow containing overspray particles, which comprises a separation device for separating the overspray from the exhaust air flow and an exhaust air duct arranged within a vertical projection of the floor space of the painting cabin;
Figure 20 is a schematic side view of the line from Figure 19;
Figure 21 is a schematic plan view from above onto the line from Figures 19 and 20; and
Figure 22 is a schematic perspective representation of the line from Figures 19 to 21.
Identical or functionally equivalent elements have been given the same references in all figures.
A line for spray painting motor vehicle bodies 102 shown in Figures 1 to 7 and given the overall reference 100 comprises a transport device 104 (shown purely schematically), by means of which the motor vehicle bodies 102 can be moved in a transport direction 106 through an application zone 108 of a painting cabin given the overall reference 110.
The transport device 104 can be configured, for example, as an inverted circular conveyor or also as an inverted monorail conveyor.
In particular, the transport device 104 can be configured in two parts and - as can best be seen from Figures 1, 3 and 4 - comprise two transport tracks 104a and 104b extending parallel to the transport direction 106, which are spaced from one another in a horizontal direction perpendicular to the transport direction 106.
The application zone 108 is the interior of the painting cabin 110, which in its horizontal transverse direction 112 running perpendicular to the transport direction 106, which corresponds to the longitudinal direction of the painting cabin 110, is defined on both sides of the transport device 104 by a respective cabin wall 114.
Spray painting devices 116 (see Figures 1 to 4), e.g. in the form of painting robots, are arranged in the painting cabin 110 on both sides of the transport device 104.
An air flow, which passes through the application zone 108 substantially vertically downwards from above, as indicated by arrows 119 in Figure 1, is generated by means of an air flow generating means 118 shown schematically in Figure 5.
This air flow takes up paint overspray in the form of overspray particles in the application zone 108.
The term "particles" in this case covers both solid and liquid particles, in particular droplets.
If a wet paint is used for painting in the line 100, then the wet paint overspray consists of paint droplets.
The largest dimension of most of the overspray particles is in the range of approximately 1 µm to approximately 100µm.The exhaust air flow represented by arrows 120 leaves the painting cabin 110 through a cabin floor 122, which is formed by air-permeable gratings 124.
The line 100 additionally comprises at least one device, given the overall reference 126 and only one device 126 shown in the figures, for separating wet paint overspray from the air flow 120, which is arranged below the application zone 108.
The device 126 comprises a substantially cuboidal flow chamber 128, which extends in the transport direction 106 over the entire length of the painting cabin 110 and beyond, and in the transverse direction 112 of the painting cabin 110 is defined by vertical side walls 130, which are substantially in alignment with the lateral cabin walls 114 of the painting cabin 110, so that the flow chamber 128 has substantially the same horizontal cross-sectional area as the painting cabin 110 and is largely arranged completely within the vertical projection of the floor space of the painting cabin 110.
The flow chamber 128 is subdivided into an upper section 136 and a lower section 138 by flow guide elements 132, which in this exemplary embodiment are configured as substantially horizontally oriented flow baffle plates 134.
The upper section 136 and the lower section 138 of the flow chamber 128 are connected to one another by means of a constricted region 140, which is in the form of a gap 142 between the opposing free edges of the flow guide elements 132 and forms a narrow point in the flow path of the exhaust air flow 120 through the flow chamber 128.
The upper sides of the flow guide elements 132 respectively form a flow guide surface 135, which directs the exhaust air flow 120 towards the constricted region 140.

A precoat feeding means 144, which discharges a precoat material continuously or at intervals into the exhaust air flow 120, is arranged at the constricted region 140 of the flow path. Alternatively, the at least one precoat feeding means (144) may be arranged in the floor region of the painting cabin (110).
The precoat feeding means 144 can be configured, for example, as a precoat spray nozzle, which discharges the precoat material in the form of a spray mist into the exhaust air flow 120.
The arrangement of the precoat feeding means 144 at the constricted region 140 of the flow path of the exhaust air flow 120 provides the advantage that, because of the increased flow rate of the exhaust air flow 120 and because of the small flow cross-section, turbulences occur in the exhaust air flow, which assure turbulence of the precoat material in the exhaust air flow 120 and thus ensure a particularly favourable distribution of the precoat material in the exhaust air flow 120.
The precoat feeding means 144 is connected to a precoat feed pipe (not shown), which feeds the precoat material in flowable state from a precoat storage container (not shown) by means of a precoat feed pump (not shown).
In principle, any medium that is able to absorb the fluid content of the wet paint overspray can be used as precoat material.
In particular, lime, aluminium silicates, aluminium oxides, silicon oxides, powdered paint or similar may be considered as precoat materials.
Aqueous dispersions of the said materials are used, for example, to make the precoat material flowable and sprayable.
If the filter arranged after the precoat feeding means 144 is not be precoated, but merely moistened, it is also possible to only incorporate a moistening agent into the exhaust air flow 120 by means of the precoat feeding means 144.
For example, demineralised water, butyl glycol or other solvents can be considered in particular as such moistening agents.
A separation device 145 for separating wet paint overspray from the exhaust air flow 120 is respectively provided on both sides of the constricted region 140 in the lower section 138 of the flow chamber 128. The separation devices 145 respectively comprise a plurality of regenerable surface filters 146 arranged spaced from one another in the transport direction 106 on both opposing vertical side walls 130 of the flow chamber 128, said surface filters projecting into the lower section 138 of the flow chamber 128 with their filter elements 148 (see in particular Figures 1, 2 and 4).
One of these regenerable surface filters 146 is shown in detail in Figures 6 and 7.
Each of the regenerable surface filters 146 comprises a hollow base body 150, on which a plurality of filter elements 154, e.g. four in each case, are held.
The filter elements 154 are substantially plate-shaped, for example, and preferably have a serrated cross-section, as evident from Figure 6, to increase the available filter surface 156.
The filter elements 154 can be configured, for example, as plates of sintered polyethylene, which are provided with a membrane of polytetrafluoroethylene (PTFE) on their outer face.
Alternatively or additionally hereto, it can also be provided that the filter elements 154 are formed from a nonwoven fabric with a PTFE coating.
The coating of PTFE respectively serves to increase the filtration class of the surface filter 146 (i.e. decrease its permeability) and moreover to prevent the wet paint overspray separated from the exhaust air flow 120 from adhering permanently.
Both the base material of the filter elements 154 and their PTFE coating have a porosity, so that the exhaust air can pass through the pores into the inner area 176 of the respective filter element 154.
In order to prevent the agglutination of the filter surface 156, this is additionally provided with a barrier layer of the precoat material discharged into the exhaust air flow.
This barrier layer is formed during operation of the device 126 simply by deposition of the precoat material discharged into the exhaust air flow 120 on the filter surface 156.
The amongst of the amount of precoat material discharged into the exhaust air flow 120 is preferably so regulated that the thickness of the barrier layer of precoat material on the filter elements 154 of the regenerable surface filters 146 lies in the range of approximately 150 µm to 200 µm, for example.
The exhaust air flow 120 sweeps over the filter surfaces 156 of the filter elements 154 of the regenerable surface filter 146, wherein both the entrained precoat material and the entrained wet paint overspray are deposited on the filter surface 156, and passes through the porous filter surfaces 156 into the inner areas 176 of the filter elements 154, which are connected to the cavity inside the base body 150.
The cleaned exhaust air flow 120 thus passes through the base body 150 respectively into an exhaust air pipe 158, which runs from the respective regenerable surface filter 146 to an exhaust air duct 160 running parallel to the transport direction 106 laterally next to a vertical side wall 130 of the flow chamber 128.
As may be seen from the schematic representation in Figure 5, the cleaned exhaust air with the wet paint overspray removed passes out of the two exhaust air ducts 160 at least partially back to the air flow
generating means 118, which feeds the cleaned exhaust air through a feed pipe 162 to the application zone 108 in the painting cabin 110 again.
Another part of the cleaned exhaust air flow is discharged to the surrounding area through a discharge nozzle 164 in an exhaust air pipe 166.
This part of the exhaust air flow discharged to the surrounding area is replaced by fresh air, which is fed to the air flow generating means 118 through a free air feed pipe 168.
The bulk of the air passed through the application zone 108 is therefore directed in an air recirculation circuit 170, which comprises the air flow generating means 118, the feed pipe 162, the application zone 108, the flow chamber 128 and the exhaust air ducts 160, as a result of which constant heating of freshly supplied additional air is avoided and the energy costs are thus significantly reduced.
Since the separation of the wet paint overspray from the exhaust air flow 120 by means of the regenerable surface filters 146 is conducted dry, i.e. without washing with cleaning fluid, the air directed in the recirculation circuit 170 is not moistened during the separation of the wet paint overspray, and therefore no devices for moistening the air directed in the recirculation circuit 170 are required at all.
Moreover, no devices are necessary for separating wet paint overspray from a washing-cleaning fluid.
The regenerable surface filters 146 are cleaned by compressed air pulses at specific time intervals, when the degree to which they are laden with wet paint overspray has reached a predetermined value.
This cleaning can be performed, for example, once per work shift, i.e. twice to three times per working day.
The necessary compressed air pulses are generated by means of a compressed air storage unit 172, which is arranged on the base body 150 of the respective regenerable surface filter 146 and is capable of discharging compressed air pulses to compressed air pipes 174, which run inside the respective base body 150 and lead from the compressed air storage unit 172 into the inner areas 176 of the filter elements 154.
From the inner areas 176 of the filter elements 154, the compressed air pulses pass through the porous filter surfaces 156 into the outer area of the filter elements 154, wherein the barrier layer of precoat material formed on the filter surfaces 156 and the wet paint overspray deposited thereon is detached from the filter surfaces 156, so that the filter surfaces 156 are returned to their original cleaned state.
The flow direction of the compressed air through a regenerable surface filter 146 during cleaning is represented by arrows 177 in Figure 7.
The store of compressed air in the compressed air storage units 172 is supplemented from a compressed air supply present on the construction side through compressed air feed pipes (not shown).
Alternatively or additionally to a cleaning by means of compressed air pulses, it can also be provided that the regenerable surface filters 146 are rinsed off by means of a suitable rinsing device at predetermined intervals in order to remove the wet paint overspray deposited on the filter surfaces 156.
As may best be seen from Figures 1 and 2, the material cleaned from the filter surfaces 156 of the regenerable surface filter 146 passes onto a collection belt 178, which is arranged on the base of the flow chamber 128 and is configured, for example, as an endless belt rotating around a driven roller 180 and an idle return roller 182.
The driven roller 180 is set in rotation by means of a drive motor 184 to set the collection belt 178 in motion in the transport direction 106.
In this way, the material consisting of precoat material and separated wet paint overspray that is passed from the regenerate surface filters 146 onto the surface of the collection belt 178 is transported by means of the collection belt 178 to a separation device (not shown), by means of which this material is detached from the collection belt 178 (e.g. by means of stripping), collected and possibly passed on for further use.
The collection belt 178 also takes up part of the wet paint overspray, which passes directly from the exhaust air flow 120 onto the collection belt 178, before the exhaust air flow 120 reaches the regenerable surface filters 146.
An alternative configuration of the regenerable surface filters 146 that can be used in the device 126 is shown in Figures 8 to 10. Instead of a plurality of vertically oriented plate-shaped filter elements arranged adjacent to one another, the regenerable surface filter shown in Figures 8 to 10 comprises a substantially cylindrical filter element 154', which likewise has a serrated filter surface 156 viewed in cross-section to increase the available filter surface 156.
In addition to the generation of compressed air pulses, in this embodiment a rinsing fluid ring conduit 186 is provided for cleaning the regenerable surface filter 146. This ring conduit sprays a rinsing fluid against the filter surface 156 of the filter element 154' through rinsing fluid outlets provided on the radial inside of the rinsing fluid ring conduit 186, so that the rinsing fluid detaches the barrier layer and the wet paint overspray deposited thereon from the filter surface 156 and conveys it onto the collection belt 178.
A second embodiment of a line 100 for painting motor vehicle bodies 102 shown in Figures 11 to 14 differs from the first embodiment described above in that in this second embodiment the flow guide elements 132, which separate the lower section 138 from the upper section 136 of the flow chamber 128 of the device 126 for separating wet paint overspray,
are not oriented substantially horizontally, as in the case of the first embodiment, but are inclined relative to the horizontal such that they slope down towards the constricted region 140, as best shown in Figure 11.
The angle of inclination relative to the horizontal preferably amounts to approximately 5° to approximately 30°.
As a result of this inclination of the flow guide elements 132 and thus of the flow guide surfaces 135 on their upper side, a funnel-shaped structure of the lower region of the upper section 136 of the flow chamber 128 is achieved, by means of which the air flow towards the constricted region 140 is rendered more uniform and the extent of the turbulences on the upper side of the flow guide elements 132 is reduced. In this way, a smaller proportion of wet paint overspray is already deposited on the flow guide surfaces 135 before the exhaust air flow 120 reaches the lower section 138 of the flow chamber 128.
In addition, the flow guide elements 132 are arranged slightly higher inside the flow chamber 128 in the second embodiment than in the first embodiment.
Otherwise, the second embodiment of a line 100 for painting motor vehicle bodies 102 shown in Figures 11 to 14 has the same structure and function as the first embodiment shown in Figures 1 to 10, and on this basis reference is made to the above description thereof.
A third embodiment of a line 100 for painting motor vehicle bodies 102 shown in Figures 15 to 18 differs from the second embodiment described above in that the constricted region 140 is not formed merely by a gap 142 between the opposing edges of the flow guide elements 132, but comprises an exhaust air shaft 188, which extends vertically downwards from the opposing edges of the flow guide elements 132 and is defined on its two longitudinal sides by vertical shaft side walls 190 extending in the transport direction 106.
Configured between the lower edge of each shaft side wall 190 and the upper side of the collection belt 178 on the base of the flow chamber 128 is a respective vertical gap 192, through which the exhaust air flow 120 exits from the constricted region 140 into the lower section 138 of the flow chamber 128, wherein in this embodiment the lower section 138 of the flow chamber 128 is subdivided into two sub-areas 138a, 138b respectively arranged on a side of the exhaust air shaft 188.
Moreover, in this embodiment the filter elements 154 of the regenerable surface filters 146 do not extend into the lower section 138 of the flow chamber 128 in a substantially horizontal direction, but rather are inclined relative to the horizontal, i.e. preferably by approximately the same angle as the flow guide surfaces 135 of the flow guide elements 132.
This angle of inclination relative to the horizontal preferably lies in the range of approximately 5° to approximately 30°.
Because of this inclination of the filter elements 154 of the regenerable surface filters 146 relative to the horizontal, the base bodies 150 of the regenerable surface filters 146 and the upper regions of the side walls 130 of the lower section 138 of the flow chamber 128 are likewise not oriented vertically, but inclined relative to the vertical by an acute angle, which corresponds to the angle of inclination of the filter elements 154 and the flow guide surfaces 135 relative to the horizontal.
In this embodiment, the regenerable surface filters 146 are particularly well protected from objects falling out of the application zone 108.
Moreover, the upper section 136 and the lower section 138 of the flow chamber 128 are disconnected from one another with respect to flow by the exhaust air shaft 188, so that the exhaust air flow in the lower section 138 of the flow chamber 128 is largely independent of the flow conditions in the upper section 136 of the flow chamber 128.

Since in this embodiment two gaps 192 are present, through which the exhaust air flow 120 enters the lower section 138 of the flow chamber 128, two precoat feeding means 144 are also provided, which are arranged respectively adjacent to one of the vertical gaps 192 at the lower end of one of the shaft side walls 190.
Otherwise, the third embodiment of a line 100 for painting motor vehicle bodies 102 shown in Figures 15 to 18 has the same structure and function as the second embodiment shown in Figures 11 to 14, and on this basis reference is made to the above description thereof.
A fourth embodiment of a line 100 for spray painting motor vehicle bodies 102 shown in Figures 19 to 22 differs from the first embodiment described above in that the device 126 for separating wet paint overspray from the exhaust air flow 120 is not configured symmetrically to the longitudinal central plane 194 of the painting cabin 110, but asymmetrically to this longitudinal central plane 194.
In particular, the regenerable surface filters 146 in this embodiment are only arranged on one side of the longitudinal central plane 194 (namely on the side shown on the left in Figure 19).
In this embodiment only a single exhaust air duct 160 is provided, which, moreover, is not arranged laterally outside the side wall 130 of the flow chamber 128, but instead is integrated into the flow chamber 128 and is arranged directly below one of the flow guide elements 132, so that the respective flow guide element 132 forms an upper boundary of the exhaust air duct 160.
The regenerable surface filters 146 in this embodiment are not connected to the exhaust air duct 160 by means of exhaust air pipes 158, but are arranged directly on a lower boundary wall 196 of the exhaust air duct 160, wherein the filter elements 154 of the regenerable surface filters 146 hang down in a substantially vertical direction from the lower boundary

wall 196 of the exhaust air duct 160 into the lower section 138 of the flow chamber 128.
A particularly efficient cleaning of the regenerable surface filters 146 is possible as a result of this hanging arrangement.
The side of the lower section 138 of the flow chamber 128 opposite the side of the flow chamber 128 provided with the regenerable surface filters 146 is separated by means of a vertical dividing wall 198 from the region of the lower section 138 of the flow chamber 128 passed through by the exhaust air flow 120.
This separated region 200 is defined upwards by one of the flow guide elements 132 and extends downwards as far as the base 202 of the flow chamber 128.
This region 200 separated from the throughflow region of the flow chamber 128 can be used, for example, to receive auxiliary units such as fans, storage containers, pumps or similar.
Alternatively or additionally hereto, it is possible to use the separated region 200 as an air duct, e.g. as an additional exhaust air duct, fresh air supply duct or exhaust air discharge duct.
The throughflow region of the lower section 138 of the flow chamber 128 is defined to the bottom by the collection belt 178.
It can be seen in particular from Figure 20 that in the region of its idle return roller 182 the collection belt 178 is cleaned by means of a stripper 204 to remove the material containing precoat material and deposited wet paint overspray collected on the surface of the collection belt 178, wherein the material stripped from the collection belt 178 passes into a mobile collecting tank 206.

When a predetermined maximum filling level is reached in the mobile collecting tank 206, the mobile collecting tank 206 is replaced by an empty mobile collecting tank 206, and the filled mobile collecting tank 206 is driven to a collection and further processing station.
Since all the components of the device 126 for separating wet paint overspray are arranged within the vertical projection of the floor space of the painting cabin 110 in the fourth embodiment shown in Figures 19 to 22, this embodiment has a particularly compact structure and is particularly suitable for confined space conditions.
Otherwise, the fourth embodiment shown in Figures 19 to 22 has the same structure and function as the first embodiment shown in Figures 1 to 10, and on this basis reference is made to the above description thereof.

WE CLAIM:-
1. Installation for painting objects, comprising at least one painting cabin
(110) and at least one device (126) for separating wet paint overspray
from an exhaust air flow (120) containing overspray particles, wherein
the overspray particles pass into the exhaust air flow (120) in an
application zone (108) of the painting cabin (110),
wherein the device (126) for separating wet paint overspray comprises
at least one separation device (145) for separating the overspray from at
least a part of the exhaust air flow (120), which has at least one
regenerable surface filter (146),
wherein the flow path of the exhaust air flow (120) from the application
zone (108) to the separation device (145) has at least one constricted
region (140), and
wherein the device (126) for separating wet paint overspray is
configured asymmetrically to a longitudinal central plane (194) of the
painting cabin (110), wherein the regenerable surface filters (146) are
arranged only on one side of the longitudinal central plane (194).
2. Installation according to Claim 1, characterised in that the constricted region (140) is arranged below the application zone (108).
3. Installation according to Claim 2, characterised in that the constricted region (140) is arranged within a vertical projection of the floor space of the painting cabin (110).
4. Installation according to one of Claims 1 to 3, characterised in that the extent of the constricted region (140) in the flow direction of the exhaust air flow (120) is shorter than 6 m.
5. Installation according to Claim 4, characterised in that the extent of the constricted region (140) in the flow direction of the exhaust air flow (120) is shorter than 1 m.
6. Installation according to Claim 5, characterised in that the extent of the constricted region (140) in the flow direction of the exhaust air flow (120) is shorter than 0.5 m.
7. Installation according to any of Claims 1 to 6, characterised in that the application zone (108) is arranged in a painting cabin (110) with a longitudinal direction (106), and that the constricted region (140) is subdivided in the longitudinal direction (106) of the painting cabin (110) into a plurality of constricted sub-regions.
8. Installation according to one of Claims 1 to 7, characterised in that the entry of the exhaust air flow (120) into the constricted region (140) is arranged above the at least one regenerable surface filter (146).
9. Installation according to any of Claims 1 to 8, characterised in that the application zone (108) is arranged in a painting cabin (110) with a transverse direction (112), and that the smallest cross-section of the constricted region (140) passed through by the exhaust air flow (120) has an extent in the transverse direction (112) of the painting cabin (110), which at most amounts to 20% of the extent of the painting cabin (110) in the transverse direction (112) of the painting cabin (110).
10. Installation according to any of Claims 1 to 9, characterised in that arranged vertically above the at least one regenerable surface filter (146) is at least one shielding element (132), which is oriented substantially horizontally at least in sections, which prevents objects, dirt and/or paint particles from falling vertically out of the application zone (108) onto the regenerable surface filter (146), and which also serves as a flow guide element which directs at least a part of the exhaust air flow (120) towards the constricted region (140).
11. An installation according to one of Claims 1 to 10, characterised in that the at least one device (126) comprises a flow chamber (128) and that a side of the flow chamber (128) lying opposite to a side of the flow chamber (128) which is provided with the regenerable surface filters (146) is separated by a dividing wall (198) from a region of the flow chamber (128) which is passed through by the exhaust air flow (120), so that a separated region (200) is formed.
12. An installation according to Claim 11, characterised in that the separated region (200) receives auxiliary units such as fans, storage containers and/or pumps and/or an exhaust air duct.
13. An installation according to Claim 11 or 12, characterised in that the flow chamber (128) including the separated region (200) is arranged substantially within a vertical projection of the floor space of the painting cabin (110).
14. An installation according to one of Claims 11 to 13, characterised in that the separated region (200) covers at least a part of a base (202) of the device (126) and is defined upwards by a flow guide element and laterally bordered by the dividing wall (198).
15. An installation according to one of Claims 1 to 14, characterised in that the device (126) comprises a flow chamber (128) which is subdivided into an upper section (136) and a lower section (138) by flow guide elements, wherein the upper section (136) and the lower section (138) are connected to one another by the constricted region (140) and the constricted region (140) comprises an exhaust air shaft which is defined by shaft side walls extending in a transport direction (106) of the objects.
16. An installation according to one of Claims 1 to 15, characterised in that
the device (126) comprises at least one exhaust air duct (160), into
which at least a part of the exhaust air flow (120) enters after passing through the separation device (145), wherein the exhaust air duct (160) is arranged within a vertical projection of the floor space of the painting cabin (110).
17. An installation according to one of Claims 1 to 16, characterised in that the at least one regenerable surface filter (146) has a barrier layer comprising a precoat material, which prevents an agglutination of the filter surface (156).
18. An installation according to Claim 17, characterised in that a collecting tank (206) for precoat material and deposited wet paint overspray is arranged vertically below the regenerable surface filter (146) and that precoat material and wet paint overspray that are cleaned off the regenerable surface filter (146) at intervals are collected in the collecting tank (206).
19. Installation according to one of Claims 17 or 18, characterised in that the installation comprises at least one precoat feeding means (144), which discharges a precoat material, into the exhaust air flow (120).
20. Installation according to Claim 19, characterised in that the precoat material comprises lime, an aluminium silicate, an aluminium oxide, a silicon oxide or powdered paint.
21. Installation according to one of Claims 1 to 20, characterised in that the at least one regenerable surface filter (146) is configured to be cleaned at intervals.
22. Installation according to one of Claims 1 to 21, characterised in that the at least one regenerable surface filter (146) has a moist surface during operation of the device (126).
23. Installation according to Claim 22, characterised in that the filter surface of the at least one regenerable surface filter (146) is configured to be rinsed off continuously or at intervals.
24. Installation according to one of Claims 1 to 23, characterised in that the device (126) has an air recirculation circuit (170), in which the exhaust air flow (120), from which the wet paint overspray has been separated, is fed, at least partially, to the application zone (108) in the painting cabin (110) again.
25. Installation according to one of Claims 1 to 24, characterised in that the at least one regenerable surface filter (146) is arranged within a vertical projection of the floor space of the painting cabin.
26. Installation according to one of Claims 1 to 25, characterised in that the objects to be painted are motor vehicle bodies (102).

Documents:

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Patent Number

270485

Indian Patent Application Number

6114/DELNP/2007

PG Journal Number

01/2016

Publication Date

01-Jan-2016

Grant Date

28-Dec-2015

Date of Filing

06-Aug-2007

Name of Patentee

DURR SYSTEMS GMBH

Applicant Address

OTTO-DURR-STRASSE 8, 70435 STUTTGART (DE)

Inventors:

#	Inventor's Name	Inventor's Address
1	WIELAND, DIETMAR	LISTSTRASSE 30, 70180 STUTTGART (DE)
2	TOBISCH, WOLFGANG	BEBELSTRASSE 108, 70193 STUTTGART (DE)
3	RUNDEL, KLAUS	KIESSTRASSE 10, 73728 ESSLINGEN (DE)
4	RAJTSCHAN, ALEXANDER	HEGAUSTRASSE 34, 70469 STUTTGART (DE)

PCT International Classification Number

B05B 15/12

PCT International Application Number

PCT/EP2006/002469

PCT International Filing date

2006-03-17

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	10 2005 013 711.3	2005-03-24	Germany