Abstract:
The invention relates to a device for removing wet paint overspray from an outgoing air flow ( 120 ) containing over-spray particles. The device separates wet paint over-spray from an over-spray particle contained in an exhaust air stream ( 120 ). The overspray particles in the exhaust air stream ( 120 ) are formed during the painting at an application area ( 108 ) of a painting installation ( 100 ). The device ( 126 ) comprises of at least one separation apparatus for separating the over-spray from the exhaust air stream ( 120 ). The separation apparatus includes a regeneratable surface filter ( 146 ) and the flow path of the exhaust air stream ( 120 ) from the application area ( 108 ) to a separating device ( 145 ) having at least one narrowed area ( 146 ). The central direction of flow of the exhaust air stream ( 120 ) remains essentially preserved in passing by the narrowed area ( 140 ).

Description:
PRIOR APPLICATIONS 
       [0001]    The present application is a continuation of U.S. patent application Ser. No. 11/886,764 filed on Jan. 23, 2009, which is a National Stage of, and claims priority to and all advantages of International Patent Application No. PCT/EP2006/002469 filed Mar. 17, 2006, on the basis of German Patent Application No. DE10/2005/013711.3 filed on Mar. 24, 2005. 
     
    
     TECHNICAL FIELD 
       [0002]    The present invention relates to a device for removing wet paint overspray from an exhaust air flow containing over-spray particles, whereby the over-spray particles in the exhaust air flow reach into an application area of a painting installation. 
       TECHNICAL BACKGROUND 
       [0003]    Such devices are used in plants for painting work parts, in particular for spray-painting vehicle bodies, in which an air flow is produced by an application area of the plant, which exhausts excess wet paint from the application area. 
         [0004]    It is well-known to separate out the carried wet paint over-spray of a washing plant from the exhaust air flow by means of a washing liquid. 
         [0005]    Known washing plants have the disadvantage, however, in particular with air circulation control, in that a high amount of moisture is supplied to the exhaust air flow from which the wet paint over-spray is separated, so that the exhaust air flow resulting after separation of the wet paint over-spray must be subjected to a energy-intensive dehumidification. 
         [0006]    Furthermore, greater expense is required for the treatment of the washing liquid loaded with the wet paint over-spray. 
         [0007]    The basic object of the present invention is to provide a device of the aforementioned type which enables a separation of the wet paint over-spray from the exhaust air flow in a simple, reliable and energy-saving way. 
         [0008]    This problem is solved according to the invention with a device having the characteristics of the generic terms of claim  1 , in that the device comprises at least one separation apparatus for separating the over-spray from at least one part of the exhaust air flow, which has at least one regeneratable surface filter, and that the flow path of the exhaust air flow from the application area to the separating apparatus comprises at least one narrowed area, whereby the central direction of flow of the exhaust air flow remains essentially preserved in passing the narrowed area. 
         [0009]    A regeneratable filter is understood to be one which has a filter surface upon which the wet paint over-spray carried by the exhaust air flow is separated-off, and that, preferably during the operating process of the device, is cleanable from the separated-off paint over-spray thereon. 
         [0010]    Such a regeneratable surface filter is a “dry” separation device in which no liquid is used for washing the over-spray particles out of the exhaust flow, but instead filter elements are used for separation of the over-spray particles from the air flow. 
         [0011]    Thereby, cleaning of the regeneratable surface filter by means of a “dry” separation device can take place, that is, without using a cleaning fluid or a “wet” cleaning device which utilizes a liquid. 
         [0012]    A “dry” separation device can also be provided with “wet” cleaning apparatus, as long as the deposition of the over-spray particles on the regeneratable separation element takes place in a dry manner, that is. 
         [0013]    A “dry” separation device can also be provided with a “wet” cleaning device, as long as the deposition of the over-spray particles on the regeneratable separation element takes place in a dry manner, that is, without washing using a washing fluid. 
         [0014]    Preferably the entire separation of wet paint over-spray from the exhaust air flow containing the over-spray particles takes place completely dry, that is, without use of a fluid for washing the over-spray particles out of the exhaust air flow. 
         [0015]    Use of a regeneratable surface filter in the separation device circumvents the necessity of providing a washing station and the associated water treatment. Thereby, the energy-consumption of the separation device and (owing to the omission of the water treatment) also the space-requirements of the device are significantly reduced. 
         [0016]    The capacity to be cleaned of the surface filter also further ensures a long service life of the filter with large quantities of resulting wet paint over-spray. 
         [0017]    In view of the provision of a narrowed range in the exhaust air flow path from the application area to the separation device, it is furthermore achieved that the regeneratable surface filter is protected against direct effects from the application area. 
         [0018]    Thereby, that the central flow direction of the exhaust air flow in passing the narrowed area remains essentially preserved, it is achieved that a premature deposition of wet paint over-spray on the boundary walls of the narrowed area is avoided. 
         [0019]    In a preferred arrangement of the device according to the invention, the narrowed area is located beneath the application area. 
         [0020]    If the application area is arranged in a painting booth, then the narrowed area is preferably disposed within a vertical projection of the basal area of the painting booth. 
         [0021]    To prevent the wet paint over-spray from the exhaust air flow from already settling on the boundary walls of the narrowed area, it is an advantage if the elongation of the narrowed area in the flow direction of the exhaust air flow is shorter than approx. 6 m, preferably shorter than approx. 1 m, in particular shorter than approx. 0.5 m. 
         [0022]    If the application area is arranged in a painting booth with a longitudinal direction, then the narrowed area preferably extends in the longitudinal direction of the painting booth over essentially the entire length of the painting booth. 
         [0023]    Thereby the narrowed area in the longitudinal direction of the painting booth can be divided into several narrowed sub-areas. 
         [0024]    Alternatively, it can also be provided that the narrowed area in the longitudinal direction of the painting booth is not divided. 
         [0025]    If the application area is disposed in a painting booth with a transverse direction, it can be provided that the narrowed area in the transverse direction of the painting booth is divided into several narrowed sub-areas. 
         [0026]    Alternatively, it can also be provided that the narrowed area in the transverse direction of the painting booth is not divided. 
         [0027]    The entrance of the exhaust air flow into the narrowed area is preferably arranged above the at least one regeneratable surface filter. 
         [0028]    If the application area is disposed in a painting booth with a transverse direction, then the smallest cross-section of the narrowed area flowed through by the exhaust air stream preferably has an extension in the transverse direction of the painting booth, which amounts to at most approx. 20% of the extension of the painting booth in the transverse direction of the painting booth. 
         [0029]    In order for the at least one regeneratable surface filter to be protected against damages, it is advantageous if at least one shielding element is arranged vertically over the at least one regeneratable surface filter, which will prevent a vertical falling down of articles, dirt and/or paint particles from the application area upon the regeneratable surface filter. 
         [0030]    Thereby it may be provided that the at least one shielding element forms the boundary of the narrowed area. 
         [0031]    In order for favorable flow conditions in the exhaust air flow path to be obtained, it is desirable if the device contain at least one flow-guidance element, which directs at least one portion of the exhaust stream to the narrowed area. 
         [0032]    Thereby the flow guidance element can feature an at least in sections, essentially horizontally aligned flow guidance surface. 
         [0033]    Alternatively, it may also be provided that the flow guidance element features a flow guidance element inclined at least in sections against the horizontal, preferably towards the narrowed area. 
         [0034]    If the device has a bottom, which limits the exhaust air flow path downward, it can be provided that at least one part of the bottom is covered by an area separated from the area of the device flowed through by the exhaust air. In this way the bottom surface area is reduced, which is contaminated by wet paint over-spray separating out of the exhaust air flow before reaching the at least one surface filter. Thereby, it can be provided that an upper boundary wall of the area separated from the area of the device flowed through by the exhaust air flow forms at least one part of a flow guidance element, which directs at least one portion of the exhaust air flow to the narrowed area. 
         [0035]    If the application area is arranged in a painting booth and the device comprises at least one exhaust air duct, into which at least one portion of the exhaust air flow enters after passing the separation device, then a special space-saving structure of the device is achieved, if the exhaust air channel is disposed within a vertical projection of the basal surface of the painting booth. 
         [0036]    In order to facilitate the cleaning of the regeneratable surface filter, it is advantageous, if the at least one exhaust air channel exhibits a barrier layer comprising a pre-coat material which prevents agglutination of the filter surface. 
         [0037]    For the barrier layer made of precoat-material to fabricate on the surface filter, it can be provided that the device comprises at least one pre-coat feeding apparatus, which delivers a pre-coat material in the exhaust air flow. 
         [0038]    Thereby, the supply of pre-coat material in the exhaust air flow can take place continuously or in intervals. 
         [0039]    As pre-coat materials, lime, aluminum silicates, aluminas, silicon oxides, powder coatings or the like are taken into consideration. 
         [0040]    In principle, any medium is suitable as a pre-coat material which has the capacity to absorb the liquid portion of the wet paint over-spray. 
         [0041]    Moreover it is possible, to arrange the at least one pre-coat feeding apparatus in direct connection to the application area, for example on the bottom area of the painting booth. 
         [0042]    But it is particularly advantageous if the at least one pre-coat feeding apparatus is disposed at the narrowed area of the exhaust air flow path. In the narrowed area of the exhaust air flow path high flow velocities control, so that by the feeding of the pre-coat material to this location a particularly good pre-coat distribution is obtained by means of venturi turbulence. 
         [0043]    With pre-coating there is the possibility of interim pre-coating, whereby a new pre-coating material is applied without prior cleaning of the surface filter, so that the later cleaning characteristics of the surface filter are improved. 
         [0044]    The at least one regeneratable surface filter of the separation device is preferably capable of being cleaned in intervals. 
         [0045]    Alternatively or additionally it can thereby be provided that the at least one regeneratable surface filter exhibits a moist surface in the operation of the device. 
         [0046]    The surface filter can be kept damp, for example, by use of rinsing- or humidification media such as demineralized water, butylglycol or other solvents, in order to facilitate the cleaning of the surface filter. 
         [0047]    These humidification media can be introduced at the same locations in the exhaust air stream as the previously described pre-coat materials. 
         [0048]    For a basic cleaning of the filter surface of the surface filter it is advantageous, if the surface of the at least one regeneratable surface filter is capable of being rinsed off continuously or in intervals. 
         [0049]    Alternatively or additionally it can thereby be provided that the at least one regeneratable surface filter is capable of being cleaned by compressed air impulses. 
         [0050]    A particularly energy-saving operation of the painting installation is possible, if the device has an air circulation cycle, in which the exhaust air flow, from which the wet paint over-spray has been separated, is at least partially re-delivered to the application area. 
         [0051]    Claim  30  directed to an installation for the painting of objects, particularly of vehicle bodies, which comprises at least one painting booth and at least one device according to the invention for separating wet paint over-spray from an over-spray particle-containing exhaust air stream. 
         [0052]    Further characteristics and advantages are the subject of the following description and graphic illustration of exemplary embodiments. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0053]    Other advantages of the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein: 
           [0054]      FIG. 1  a schematic vertical cross-section through a first embodiment of a painting booth with a device arranged under it for separating wet paint over-spray from an over-spray particle-containing exhaust air stream, which includes two separation devices for separating the over-spray from the exhaust air stream and also two exhaust ducts, which run laterally to the left and/or right alongside the floor plan of the painting booth, whereby a narrowed area of the flow path of the exhaust air stream is provided between an application area of the painting booth and the separation devices, which is bounded by horizontally aligned flow guidance elements; 
           [0055]      FIG. 2  a schematic side view of the installation of  FIG. 1 ; 
           [0056]      FIG. 3  a schematic top view from above of the installation of  FIGS. 1 and 2 ; 
           [0057]      FIG. 4  a schematic representation in perspective of the installation of  FIG. 1  to  FIG. 3 ; 
           [0058]      FIG. 5  a schematic representation of an air circulation cycle of the installation of  FIGS. 1 to 4 ; 
           [0059]      FIG. 6  a schematic representation in perspective of a regeneratable surface filter of the installation of  FIG. 1 - FIG. 5 ; 
           [0060]      FIG. 7  a schematic longitudinal section through the surface filter of  FIG. 6 , which illustrates a cleaning process of the surface filter; 
           [0061]      FIG. 8  a schematic representation in perspective of an alternative embodiment of a regeneratable surface filter; 
           [0062]      FIG. 9  a schematic cross-section through the surface filter of  FIG. 8 , which illustrates a cleaning process of the surface filter; 
           [0063]      FIG. 10  a schematic top view from above the surface filter of  FIGS. 8 and 9 ; 
           [0064]      FIG. 11  a schematic cross-section through a second embodiment of a painting booth with a device arranged under it for separating wet paint over-spray from an exhaust air stream containing over-spray particles, which includes two separation devices for separating the over-spray from the exhaust air stream and also two exhaust ducts, which run laterally to the left and/or right alongside the floor plan of the painting booth, whereby a narrowed area of the flow path of the exhaust air stream is provided between an application area of the painting booth and the separation devices, which is bounded by flow guidance elements which are inclined against the horizontal; 
           [0065]      FIG. 12  a schematic side view of the installation of  FIG. 11 ; 
           [0066]      FIG. 13  a schematic top view from above of the installation of  FIGS. 11 and 12 ; 
           [0067]      FIG. 14  a schematic representation in perspective of the installation of  FIG. 11  to  FIG. 13 ; 
           [0068]      FIG. 15  a schematic cross-section through a third embodiment of a painting booth with a device arranged under it for separating wet paint over-spray from an exhaust air stream containing over-spray particles, which includes two separation devices for separating the over-spray from the exhaust air stream and also two exhaust ducts, which run laterally to the left and/or right alongside the floor plan of the painting booth, whereby between an application area of the painting booth and the separation devices a narrowed area of the flow path of the exhaust air stream is provided in the form of a shaft extending in a vertical direction; 
           [0069]      FIG. 16  a schematic side view of the installation of  FIG. 15 ; 
           [0070]      FIG. 17  a schematic top view from above of the installation of  FIGS. 15 and 16 ; 
           [0071]      FIG. 18  a schematic representation in perspective of the installation of  FIG. 15  to  FIG. 17 ; 
           [0072]      FIG. 19  a schematic cross-section through a fourth embodiment of a painting booth with a device arranged under it for separating wet paint over-spray from an exhaust air stream containing over-spray particles, which includes a separation device for separating the over-spray from the exhaust air stream and an exhaust duct arranged within a vertical projection of the basal surface of the painting booth; 
           [0073]      FIG. 20  a schematic side view of the installation of  FIG. 19 ; 
           [0074]      FIG. 21  a schematic top view from above of the installation of  FIG. 19  and  FIG. 20 ; and 
           [0075]      FIG. 22  a schematic representation in perspective of the installation of  FIGS. 19 to 21 . 
       
    
    
       [0076]    Equal or functionally equivalent elements are designated in the figures with the same reference symbols. 
       DETAILED DESCRIPTION 
       [0077]    An installation shown in  FIGS. 1 to 7 , marked  100  as a whole for the spray-coating of vehicle bodies  102  which includes a clearly schematically represented conveyer device  104 , by means of which the vehicle bodies  102  can be moved along in a conveying direction  106  through an application area  108  of a painting booth marked  110  as a whole. 
         [0078]    The conveying device  104  can, by way of example, be constructed as an inverted circular conveyer or as an inverted monorail conveyer. 
         [0079]    In particular the conveyer device  104  can be formed in two parts and—as best understood from  FIGS. 1, 3 and 4 —includes two conveyer belts  104   a  and  104   b  extending parallel to the conveyer  106 , which are spaced apart from one another in a horizontal direction perpendicular to the conveyer  106 . 
         [0080]    The application area  108  is the interior chamber of painting booth  110 , which perpendicular of it to the conveyer  106 , which corresponds to the longitudinal direction of the painting booth  110 , it is limited, respectively, by a booth wall  114  running in horizontal transverse direction  112  on both sides of the conveyer device  104 . 
         [0081]    On both sides of the conveyer device  104  spray-painting devices  116  (see  FIGS. 1-4 ) are arranged in the painting booth  110 , for example, in the form of paint application robots. 
         [0082]    By means of a compressed air production device  118  schematically represented in  FIG. 5  an air stream is produced which essentially pervades the application area vertically from top to bottom, as indicated by the arrow  119  in  FIG. 1 . 
         [0083]    This air stream takes up paint over-spray in the form of over-spray particles in the application area  108 . 
         [0084]    The term “particle” includes solid as well as liquid components, particularly drops. 
         [0085]    A wet paint is used for coating in the installation  100 , thus the wet paint over-spray consists of paint drops. 
         [0086]    Most of the over-spray particles have a largest size of in a range from approx. 1 gm to approx. 100 pm. 
         [0087]    The exhaust air flow designated by the arrow  120  leaves the painting booth  110  through a booth bottom  122 , which contains an air-permeable lattice grate  124 . 
         [0088]    The installation  100  also includes a device marked  126  as a whole, for separating wet paint over-spray from the air flow  120 , which is arranged beneath the application area  108 . 
         [0089]    The device  126  includes an essentially quadrangular-shaped flow chamber  128 , which reaches over into the conveyer  106  over the whole length of the painting booth  110  and is bounded in the transverse direction  112  of the painting booth  110  by vertical side-walls  130 , which align essentially with the lateral booth-walls  114  of the painting booth  110 , so that the flow chamber  128  has essentially the same horizontal cross-sectional area as the painting booth  110  and is arranged essentially completely within the vertical projection of the basal surface of the painting booth  110 . 
         [0090]    The flow chamber  128  is subdivided by flow guidance elements  132 , which in this exemplary embodiment are formed as essentially horizontal flow guidance plates  134 , into an upper section  136  and a lower section  138 . 
         [0091]    The upper section  136  and lower section  138  of the flow chamber  128  are connected to each other by a narrowed area  140 , which is in the form of a space  142  between the free borders opposite to each other of the flow guidance elements  132  and which forms a narrowing in the flow path of the exhaust air stream  120  through the flow chamber  128 . 
         [0092]    The upper sides of the flow guidance elements  132  form in each case a flow guidance surface  135 , which directs the exhaust air stream to the narrowed area  140 . 
         [0093]    A pre-coat feed device  144  is arranged at the narrowed area  140  of the flow path, which continuously or interval-wise supplies a pre-coat material into the exhaust air stream  120 . 
         [0094]    The pre-coat feed device  144  can, for example, be designed as a pre-coat spray nozzle, which supplies the pre-coat material in the form of a spray mist into the exhaust air stream  120 . 
         [0095]    The arrangement of the pre-coat feed device  144  at the narrowed area  140  of the exhaust air stream  120  offers the advantage, that there due to the elevated flow velocity of the exhaust air stream  120  and because of the small passage cross-section, turbulences appear in the exhaust air stream, which make possible a swirling of the pre-coat material in the exhaust air stream  120  and consequent particularly good distribution of the pre-coat material in the exhaust air stream  120 . 
         [0096]    The pre-coat supply device  144  is attached to a (not shown) pre-coat feed pipe which feeds the pre-coat material in flowable condition via a (not shown) pre-coat feed pump from a (not shown) pre-coat storage container. 
         [0097]    In principle, any medium is suitable as a pre-coat material which has the capacity to absorb the liquid portion of the wet paint over-spray. 
         [0098]    For example, as pre-coat materials, lime, aluminum silicates, aluminas, silicon oxides, powder coatings or the like are taken into consideration. 
         [0099]    In order to make the pre-coat material flowable and sprayable, i.e. aqueous dispersions of the aforementioned materials are used. 
         [0100]    If the filter sequential to the pre-coat feed device  144  is not to be pre-coated, but should only be moisturized, then also only a moisturizing medium can be introduced into the exhaust air stream  120  by means of the pre-coat feed device  144 . 
         [0101]    As such, moisturizing media in particular i.e., demineralized water, butylglycol or other solvents are taken into consideration. 
         [0102]    A separation device  145  for separating wet paint over-spray from the exhaust air stream  120  is provided in the lower section  138  of the flow chamber  128  on both sides, respectively, of the narrowed area  140 . The separation devices  145  include several regeneratable surface filters  146 , spaced apart from each other on the conveyer  106 , arranged, respectively, opposite to one another on both sides of the vertical side-walls  130  of the flow chamber  128 , which with their filter elements  148  extend into the lower section  138  of the flow chamber  128  (see in particular  FIGS. 1, 2 and 4 ). 
         [0103]    This regeneratable surface filter  146  is shown in detail in  FIGS. 6 and 7 . 
         [0104]    Each of the regeneratable surface filters  146  contains a hollow fundamental body  150 , to which several, for example, four filter elements  154  are attached. 
         [0105]    Filter elements  154  are, for example, are formed essentially in a plate shape and preferably feature, as is seen from  FIG. 6 , a serrated cross-section, in order for the available filter surface  156  to be enlarged. 
         [0106]    The filter elements  154  can be formed, for example, as plates made from sintered polyethylene, which are provided with a polytetrafluoroethylene (PTFE) membrane on their outer surface. 
         [0107]    Alternatively or additionally, it can also be provided that the filter elements  154  are made of a non-woven fabric with a PTFE coating. 
         [0108]    For this reason, the PTFE coating serves, as the case may be, to raise the filter quality of the surface filter  146  (that is, to diminish its&#39; permeability) and also to prevent the permanent adhesion of the wet paint over-spray deposited from the exhaust air stream  120 . 
         [0109]    Both the base material of the filter element  154  and its&#39; PTFE-coating exhibit a porosity, so that the exhaust air can pass through the pores into the interior space  176  of the respective filter element  154 . 
         [0110]    To prevent the agglutination of the filter surface  156 , it is further provided with a barrier layer formed from the pre-coat material supplied in the exhaust air stream  120 . 
         [0111]    This barrier layer easily forms itself in the operation of device  126  by deposition on the filter surface  156  of the pre-coat material released in the exhaust air stream  120 . 
         [0112]    Preferably, the amount of pre-coat material released into the exhaust air stream  120  is regulated, so that the thickness of the barrier layer made from the pre-coat material on the filter element  154  of the regeneratable surface filter  146  is in the range of i.e. approx. 150 pm to 20011 m. 
         [0113]    The exhaust air stream  120  overcoats the filter surfaces  156  of the filter element  154  of the regeneratable surface filter  146 , whereby both the carried pre-coat material and also the carried wet paint over-spray is deposited upon the filter surfaces  156 , and passes through the porous filter surfaces  156  into the interior space  176  of the filter element  154 , which are connected with the hollow space within the fundamental body  150 . 
         [0114]    The purified exhaust air stream  120  thus by going through the fundamental body  150  passes, respectively, into an exhaust air pipet  158 , which leads from the respective regeneratable surface filter  146  to an exhaust air duct  160  on the side next to a vertical side-wall  130  of the flow chamber  128 , which duct runs parallel to conveyer  106 . 
         [0115]    As is clear from the schematic representation of  FIG. 5 , the purified exhaust air from the wet paint over-spray passes out of the two exhaust air ducts  160  at least partially back to the air flow production device  118 , which conducts the purified exhaust air via a supply line  162  once again to the application area  108  in the painting booth  110 . 
         [0116]    Another part of the purified exhaust air stream is delivered via an exhaust air blower  164  in an exhaust air supply line  166  to the surrounding area. 
         [0117]    This part of the exhaust air stream delivered to the surrounding area is replaced by fresh air, which is fed to the air flow production device  118  via a fresh air supply line  168 . 
         [0118]    The main part of the air led through the application area  108  is thus guided in an air circulation cycle  170 , which includes the air production device  118 , the supply line  162 , the application area  108 , the flow chamber  128  and the exhaust air duct  160 , whereby a constant heating of the fresh delivered supply air is avoided and thereby the energy costs are significantly lowered. 
         [0119]    Since the separation of the wet paint over-spray from the exhaust air stream  120  by means of the regeneratable surface filter  146  takes place dry, that is, without washing with a cleaning fluid, the air guided in the air circulation cycle  170  is not humidified in the separation of the wet paint over-spray, so that no devices for humidification of the air guided in the air circulation cycle  170  are necessary at all. 
         [0120]    Furthermore, no devices are necessary for separating the wet paint over-spray from a washout-cleaning fluid. 
         [0121]    The regeneratable surface filter  146  is cleaned by compressed air impulses in determined time intervals, when its&#39; coating by wet paint over-spray reaches a preset amount. 
         [0122]    This cleaning can take place, i.e. one time per work shift, that is, two or three times per work day. 
         [0123]    The required compressed air impulse is produced by a compressed air reservoir  172 , which is arranged at the fundamental body  150  of the respective regeneratable surface filter  146  and thereby is in the position, to deliver compressed air impulses to a compressed air pipe  174 , which runs within the respective fundamental body  150  and leads from the compressed air reservoir into the interior space  176  of the filter element  154 . 
         [0124]    From the interior spaces  176  of the filter element  154  the compressed air impulse passes through the porous filter surfaces  156  into the outer space of the filter element  154 , whereby the barrier layer formed from pre-coat material on the filter surfaces  156  and the wet paint over-spray deposited on the filter surfaces  156  are dissolved, so that the filter surfaces  156  are converted back into their cleansed original condition. 
         [0125]    The flow direction of the compressed air through a regeneratable surface filter  146  during the cleaning is designated in  FIG. 7  by the arrow  177 . 
         [0126]    The compressed air reserve in the compressed air reservoir  172  is replenished by (not shown) compressed air supply lines from an on-site compressed air network. 
         [0127]    A cleaning by compressed air impulses can alternatively or additionally be modified such that the regeneratable surface filter  146  is washed out by means of suitable spray device in specified intervals, in order to remove the wet paint over-spray deposited on the filter surfaces  156 . 
         [0128]    As is best seen from  FIGS. 1 and 2 , the material cleaned off from the filter surfaces  156  of the regeneratable filter  146  arrives at a collecting belt  178  at the bottom of the flow chamber  128 , which is designed, i.e. as a endless belt circulating via a driven roller  180  and a non-driven guide roller  182 . 
         [0129]    The driven roller  180  is made to rotate by means of a drive motor  184 , in order to shift the collection belt  178  in motion lengthwise of the conveyer  106 . 
         [0130]    In this way, via the collection belt  178  the material deposited on the surface of the collection belt  178  from the regeneratable surface filter  146 , which includes pre-coat material and deposited wet paint over-spray, is transported to a (not shown) separating device, from which this material (i.e. by means of a stripping device) is dissolved, collected and if necessary, recycled. 
         [0131]    The collection belt  178  also takes up a part of the wet paint over-spray which deposits directly from the exhaust air stream  120  onto the collection belt  178 , before the exhaust air stream  120  reaches the regeneratable surface filter  146 . 
         [0132]    An alternative development of the regeneratable surface filter  146 , which is usable in the device  126 , is shown in  FIGS. 8 to 10 . 
         [0133]    The regeneratable surface filter  146  includes instead of multiple, vertically oriented plate-shaped filter elements arranged next to one another, an essentially cylindrical filter element  154 ′, which also contains, viewable in the cross-section, a serrated filter surface  156  for enlargement of the available filter surface  156 . 
         [0134]    In addition, in this embodiment for production of the compressed air impulse, a rinsing liquid loop  186  is provided for cleaning of the regeneratable surface filter  146 , which sprays a rinsing liquid through to the radial inner surface of the rinsing liquid delivery port of the rinsing liquid loop  186  against the filter surface  156  of the filter element  154 ′, so that the rinsing liquid dissolves the barrier layer and the wet paint over-spray deposited on the filter surface  156  and carried on the collection belt  178 . 
         [0135]    The second embodiment shown in  FIGS. 11-14  of an installation  100  for painting of vehicle bodies  102  is thereby distinguished from the above-mentioned first embodiment, in that the flow guidance elements  132 , which divide the lower section  138  from the upper section  136  of the flow chamber  128  of the device  126  for separation of the wet paint over-spray, are not in this second embodiment, in contrast to the first embodiment, aligned essentially horizontally, but rather, as is best seen from  FIG. 11 , but are inclined against the horizontal, so that they slope towards the narrowed area  140 . 
         [0136]    The angle of inclination against the horizontal is preferably approx. 5° to approx. 30°. 
         [0137]    Via this inclination of the flow guidance elements  132  and therewith the flow line surfaces  135  at their top side, a funnel-shaped form of the lower area of the upper section  136  of the flow chamber  128  is obtained, through which the air stream is comparatively measured out to the narrowed area  140  and the extent of turbulences at the top side of the flow guidance elements is reduced. In this way, a lesser portion of the wet paint over-spray is already deposited on the flow line surfaces  135 , before the air stream  120  reaches the lower section  138  of the flow chamber  128 . 
         [0138]    Furthermore, the flow guidance elements  132  in the second embodiment are set somewhat higher within the flow chamber  128  than in the first embodiment. 
         [0139]    Apart from that, the second embodiment shown in  FIGS. 11 to 14 , of an installation  100  for painting vehicle bodies  102  agrees with respect to structure and function with the first embodiment shown in  FIGS. 1-10 , insofar as its&#39; aforementioned description is concerned. 
         [0140]    A third embodiment shown in  FIGS. 15-18  of an installation  100  for painting vehicle bodies  102  is thereby distinguished from the previously described second embodiment, in that the narrowed area  140  is formed not only by a space  142  between the borders arranged opposite to each other of the flow guidance elements  132 , but rather includes an exhaust air shaft  188  extending vertically downwards from borders arranged opposite to each other of the flow guidance elements  132 , which is bounded on both its&#39; side-walls by vertical side-wall ducts  190  extending in the conveyer  106 . 
         [0141]    Between the lower border of each side-wall duct  190  and the top side of the collection belt  178  a vertical space  192  is respectively formed, through which the exhaust air stream exits from the narrowed area  140  into the lower section  138  of the flow chamber  128 , whereby the lower section  138  of the flow chamber  128  in this embodiment is divided into two sub-areas  138   a,    138   b  arranged on the side of the exhaust air shaft  188 . 
         [0142]    Furthermore, in this embodiment the filter elements  154  of the regeneratable surface filter  146  do not extend in essentially horizontal direction into the lower section  138  of the flow chamber  138 , but rather are inclined to a greater degree against the horizontal, and in fact are inclined preferably at about the same angle as the flow guidance surfaces  135  of the flow guidance elements  132 . 
         [0143]    This angle of inclination against the horizontal is preferably in the range from approx. 5° to approx. 30°. 
         [0144]    On the basis of this inclination of the filter elements  154  of the regeneratable surface filter  146  opposite to the horizontal, the fundamental body  150  of the regeneratable surface filter  146  and the top area of the side-walls  130  of the lower section  138  of the flow chamber  128  are also not vertically aligned, but rather are inclined against the vertical around a sharp corner, which corresponds to the angle of inclination of the filter elements  154  and the flow guidance surfaces  135  towards the horizontal. 
         [0145]    In this embodiment the regeneratable surface filters  146  are especially well protected against objects falling from the application area  108 . 
         [0146]    Moreover, the top section  136  and the lower section  138  of the flow chamber  128  are fluidic decoupled from each other by the air exhaust shaft  188 , so that the exhaust air stream in the lower section  138  of the flow chamber  128  is independent to a large extent from the flow conditions in the top section  136  of the flow chamber  128 . 
         [0147]    Since in this embodiment two spaces  192  are present, through which the exhaust air stream  120  enters into the lower section  138  of the flow chamber  128 , two pre-coat feeding devices  144  are also provided, which respectively are arranged adjacent to one of the vertical spaces  192  at the lower end of one of the shaft side-walls  190 . 
         [0148]    In addition, the third embodiment shown in  FIGS. 15-18  of an installation  100  for painting of vehicle bodies  102  agrees with respect to structure and function with the first embodiment shown in  FIGS. 11-14 , insofar as its&#39; aforementioned description is concerned. 
         [0149]    A fourth embodiment shown in  FIGS. 19-22  of an installation  100  for painting of vehicle bodies  102  is thereby distinguished from the previously described first embodiment, in that the device  126  for separating wet paint over-spray from the exhaust air stream  120  is not symmetrical to the longitudinal central plane  194  of the painting booth  110 , but rather is asymmetrical to this longitudinal central plane  194 . 
         [0150]    In particular, the regeneratable filter surfaces  146  in this embodiment are arranged only on one side of the longitudinal central plane  194  (namely, see the side depicted on the left in  FIG. 19 ). 
         [0151]    In this embodiment only a single exhaust air duct  160  is provided, which however is not arranged on the side outside of the side-wall  130  of the flow chamber  128 , but instead is integrated into the flow chamber  128 , and is arranged directly under one of the flow guidance elements  132 , so that the affected flow guidance element  132  forms an upper boundary of the exhaust air chamber  160 . 
         [0152]    In this embodiment, the regeneratable surface filters  146  are not connected via exhaust air pipe  158  with the exhaust air chamber  160 , but rather are arranged directly at a lower boundary wall  196  of the exhaust air chamber  160 , whereby the filter elements  154  of the regeneratable surface filter  146  hang down in essentially vertical direction from the lower boundary wall  196  of the exhaust air duct  160  into the lower section  138  of the flow chamber  128 . 
         [0153]    By this pendent arrangement, a particularly efficient cleaning of the regeneratable surface filter  146  is obtained. 
         [0154]    The side of the flow guidance chamber  128  lying opposite to the side of the lower section  138  of the flow chamber  128  which is provided with the regeneratable surface filter  146  is separated by a vertical dividing wall  198  from the region of the lower section  138  of the flow chamber  128  which is flowed-through by the exhaust air flow stream  120 . 
         [0155]    This separated area  200  is upwardly bordered by one of the flow guidance elements  132  and extends downwards up to the base  202  of the flow chamber  128 . 
         [0156]    This area  200  which is separated from the flowed-through chamber  128  can, for example, be used for the uptake of auxiliary attachments, such as blowers, storage containers, pumps or the like. 
         [0157]    Alternatively or additionally, it is possible to use the separated area  200  as an air duct, i.e. as an additional exhaust air duct, fresh air supply duct or exhaust air discharge duct. 
         [0158]    The flowed-through area of the lower section  138  of flow chamber  128  is bordered downwards by the collection belt  178 . 
         [0159]    In particular it is clear from  FIG. 20  that the collection band  178  is not cleaned in the area of its&#39; non-driven guide roller  182  via a stripping device  204  of the material collected from the surface of the collection belt  178 , which contains pre-coat material and deposited wet pain over-spray, whereby the material stripped-off by the collection belt  178  is deposited into a mobile storage container  206 . 
         [0160]    If in the mobile storage container  206  a specified highest fill level is reached, the mobile storage container  206  is exchanged for an empty mobile storage container and the filled mobile storage container  206  is conveyed to a (not shown) collection and recycling station. 
         [0161]    Since in the fourth embodiment shown in  FIGS. 19-22  all components of the device  126  for separating wet paint over-spray are arranged within the vertical projection of the basal surface of the painting booth  110 , this embodiment is particularly compact in construction and is specially suited for crowded space conditions. 
         [0162]    Moreover, the fourth embodiment shown in  FIGS. 19-22  agrees in respect to structure and function with the first embodiment shown in  FIGS. 1-10 , insofar as its previous description is concerned. 
         [0163]    Obviously, many modifications and variations of the present invention are possible in light of the above teachings and the foregoing invention has been described in accordance with the relevant legal standards; thus, the description is merely exemplary rather than limiting in nature. Variations and modifications to the disclosed embodiment may become apparent to those skilled in the art and do come within the scope of the invention. Accordingly, the scope of the legal protection afforded this invention can only be determined by studying the following claims.