Patent Publication Number: US-2020276605-A1

Title: Installation and method for coating objects

Description:
The invention relates to a plant for coating objects, in particular vehicle bodies and/or vehicle body parts with
     a) a coating booth comprising an air supply space and an application area, which are spatially separated by a flow-permeable booth ceiling;   b) an air system configured such that conditioned air can be supplied to the air supply space and this conditioned air continues to flow as booth air through the application area;
 
wherein
   c) at least one application device is arranged in the application area and overspray occurs in the application area, which is taken up and carried along by the booth air.   

     Furthermore, the invention relates to a method for coating objects, in particular vehicle bodies and/or vehicle body parts. 
     In the manual or automatic application of paints to objects, a partial flow of the paint, which generally contains both solids and/or binders and solvents, is not applied to the object. This partial flow is called “overspray” by experts. The overspray is captured by the booth air flow in the treatment booth and is supplied to a separating unit so that the air can be returned to the coating booth after suitable conditioning if necessary. 
     In order to obtain reproducible painting results, it is desirable in coating booths that the flow velocity at which the booth air flows from top to bottom through the application area is largely constant over the area of the application area and that the flow is homogeneous overall. 
     In order to achieve this, the air supply space in plants known from the market has a relatively large volume so that the air can calm on its way through the air supply space to the flow-permeable booth ceiling and swirling and turbulence can be dissolved. The required volume is achieved by the build height of the air supply space. 
     In such systems, the height of the application area between the booth ceiling and a booth floor is, for example, about 4.5 m and the height of the air supply space between a ceiling of the air supply space and the booth ceiling is, for example, about 3.0 m. 
     Below the application area there is usually a lower plant part, in which there is a relaxation area for the booth air loaded with overspray, which leads to a separating area also located in the lower plant part and a separating device received there, with which the booth air can be freed from the overspray. The relaxation area serves the purpose of giving the booth air loaded with overspray time to calm in terms of flow, since it should reach the separating device as a flow as homogeneous as possible. On its way through the application area, the booth air is swirled again by the superstructures present there, especially by the application equipment in the form of painting robots and by the present conveyor technology, but also by the objects to be painted themselves. Overall, the relaxation area serves to reduce and at best eliminate flows in the longitudinal direction of the coating booth. 
     The lower plant part is, for example, approximately 4.0 m high in plants known from the market and extends from the booth floor to a set-up surface of the coating booth. 
     The total height of such a coating booth, without further superstructures on the air supply space, is thus approximately 11.50 m, wherein the height of the application area is approximately 40% of the total height, the height of the air supply space is approximately 66% of the height of the application area and the height of the relaxation area is approximately 33% of the height of the application area. A coating booth usually comprises an elaborate steel construction. 
     These conditions also apply to other total heights of coating booths. Due to the overall dimensions and in particular the overall height of the coating booths, a large amount of steel material is therefore required, which increases the overall costs. 
     There is now a market demand for plants with coating booths with lower build heights. The application area can thereby only be limited in height to a very small extent. Also the air supply space is not suitable in principle to save overall height, because it must provide a sufficient flow path. 
     It is therefore the object of the invention to provide a plant and a method of the kind mentioned above which take these thoughts into account. 
     This object is solved in the case of a plant mentioned at the beginning in that
     d) the air system comprises a flow guiding device with a flow straightening structure configured such that the flow of the air supplied to the air supply space is homogenized.   

     According to the invention, it has been recognized that, contrary to the opinion explained above, it is possible to save height in the air supply space if a flow straightening structure with the effect explained above is provided. In this case, the supplied air does not need a long flow path in order to flow sufficiently homogeneously into the application area. 
     It is thereby particularly favourable if the booth air flows into the application area as a substantially laminar flow. 
     It is advantageous if the flow straightening structure is arranged on the booth ceiling of the application area and thereby abuts the booth ceiling or is arranged at a distance from the booth ceiling or is integrated into the booth ceiling. 
     The flow straightening structure is preferably arranged in the air supply space or in the application area. 
     It is particularly effective if the flow straightening structure comprises a plurality of flow passages. 
     A homogeneous flow is achieved if the flow passages are polygonal, rectangular, circular or elliptical in cross-section. 
     The flow straightening structure is particularly effective when flow passages are hexagonal in cross-section. 
     The flow straightening structure can be easily installed if it is formed as a flexible or rigid flow mat. 
     Preferably, the flow straightening structure comprises a honeycomb structure with a honeycomb diameter between approximately 3 mm and approximately 20 mm and a height between approximately 3 mm and approximately 300 mm. 
     The flow straightening structure can advantageously be made of metal or a metal alloy, in particular aluminium, of a fibre composite material, in particular of an aramide paper impregnated with phenolic resin, or of plastic, in particular of polycarbonate or polyetherimide. 
     To ensure good and uniform penetration of the application area with booth air, it is advantageous if the flow straightening structure extends over at least 80% of the width of the application area and over substantially the longitudinal extension of the application area. 
     In addition, it can be advantageous if the flow guiding device comprises a flow guiding structure configured such that air supplied to the air supply space is guided in the direction towards the flow straightening structure. In this way, the required flow path in vertical direction can be shortened further if necessary. 
     It is advantageous if the flow guiding structure divides the air supply space in the longitudinal direction into at least two partial spaces. 
     This is particularly advantageous if the air system is configured such that conditioned air is supplied to the air supply space from the side in relation to the longitudinal direction of the coating booth. By means of the flow guiding structure it is then prevented that flows moving towards each other mix, which would lead to undesired strong swirling in the air supply space, which, if necessary, cannot be calmed without further measures until the air enters the application area. 
     The principle explained above can be used particularly advantageously if the coating booth comprises a separating area into which booth air loaded with overspray flows and in which a separating device for separating overspray is arranged, by means of which a large part of at least the solids of the overspray can be separated from the booth air. 
     For effective guiding of the booth air loaded with overspray to the separating area, it is advantageous if a relaxation area is arranged between the separating area and the application area, via which booth air loaded with overspray is guided to the separating device in the separating area. 
     If the separating device is associated with one or more conveying fans that extract booth air out of the relaxation area to the separating device and through it, the relaxation area in turn can be reduced in height because the flow is directed and homogenized by the additional active suction. 
     It is structurally favourable if the height of the application area defined by the distance between the booth ceiling and a booth floor is approximately 50% to 75% of the total height of the coating booth defined by the distance between a ceiling of the air supply space, referred to as the plenum ceiling, and the set-up surface of the coating booth. 
     It is also advantageous if the height of the air supply space defined by the distance between the plenum ceiling and the booth ceiling is approximately 5% to 25% of the height of the application area. 
     Preferably, the plant comprises a separating area and a relaxation area with a height of the relaxation area which is defined by the distance between a booth floor of the application area and the separating area and is approximately 5% to 25% of the height of the application area. 
     The above-mentioned object is also solved in the case of a method of the type mentioned at the beginning, in that a plant having some of all of the features described above is used. 
    
    
     
       Embodiments of the invention are explained in more detail below based on the drawings. 
         FIG. 1  shows a plant for coating objects with a coating booth in a front view, wherein by means of an air system conditioned air can be supplied to an air plenum, the conditioned air continuing to flow as booth air through an application area, and the air system comprises a flow guiding device with which the flow of the air supplied to the air plenum can be homogenized; 
         FIG. 2  shows a front view of a coating booth of a plant for coating objects with a modified flow guiding device; 
         FIG. 3  shows a front view of a coating booth of a plant for coating objects with a flow guiding device which has been modified again; 
         FIG. 4  shows a perspective view of the coating booths according to  FIGS. 1 to 3 , in which an adjusting device of the air system is provided, by means of which the supply of air into the air plenum can be adjusted. 
     
    
    
       FIG. 1  shows a coating booth  10  of a plant, referenced to as a whole by  14 , for the coating of objects  14 . Vehicle bodies  16  being painted in the coating booth  10  are shown as an example of objects  14  to be coated and of the coating process. Other objects, in particular vehicle body parts or add-on parts for vehicle bodies, but also other objects can be coated in the coating booth  10 . 
     The coating booth  10  comprises an application area  18 , which in the present embodiment is defined by an application tunnel  20 , which is limited by vertical side walls  22 , a booth ceiling  24  and a booth floor  26 , but is open at the end faces. 
     The vehicle bodies  16  are transported from the entrance side of the application tunnel  20  to its exit side by a conveyor system  28 , which is received in the application area  18  and is known in and of itself. Inside the application tunnel  20  there are application devices  30  in the form of multi-axis application robots  32 , as they are also known in and of themselves. By means of the application robots  32 , the vehicle bodies  16 , or other objects to be coated  14 , can be coated with the corresponding material. Overspray occurs in the application area  18  when coating material is applied to the objects  14 . 
     The booth ceiling  24  is flow-permeable and separates the application area  18  spatially, i.e. not fluidically, from an air supply space  34  arranged above it, which is referred to as an air plenum among experts; for this reason, the term air plenum  34  will also be used here. The booth ceiling  24  as such is configured as a filter ceiling  36  in the present embodiment, as is known in and of itself. 
     The air plenum  34  is bounded by a downwardly open plenum housing  38  with plenum side walls  40 , a plenum ceiling  42  and plenum end walls  44 , wherein only one of the plenum end walls  44  is shown in  FIG. 4 .  FIG. 4  also shows at the ends of the coating booth  10  respective I-beams of the steel structure mentioned at the beginning, which among other things support the grating  50  not shown and are not specially marked with reference signs. 
     Conditioned air can be supplied to the air plenum  34  by means of an air system  46 , the conditioned air flowing through the booth ceiling  24  as booth air further down through the application area  18 . The overspray in the application area  18  is taken up and carried along by the booth air. 
     The application tunnel  20  is open towards the bottom towards a plant part  48  arranged below it such that the booth floor  26  is also flow-permeable. For this purpose, the booth floor  26  is configured as a grating  50  which can be walked on. In the lower plant part  48 , overspray particles carried along by the booth air are separated from the booth air. This will be discussed in more detail below. 
     The more homogeneous and uniform the flow of booth air coming from the air plenum  34  through the application area  18  in relation to its base area is, the more effectively and reproducibly the objects  12  can be coated with coating material. In particular, the booth air flows as a laminar flow along the objects  12  to be coated, so that substantially comparable conditions prevail at the objects  12  over the duration of the coating process. 
     In addition, the booth air can take up and carry away the overspray that occurs there. It is of particular importance that the flow of booth air enters and passes through the entire width of the application area  18  substantially homogeneous and uniform. 
     For this purpose, the air system  46  comprises a flow guiding device  52  for homogenizing the booth air flowing from the air plenum  34  into the application area  18 . The flow guiding device  52  comprises a flow straightening structure  54  configured such that the flow of the air supplied to the air plenum  34  is homogenized. Overall, the flow guiding device  52  thus provides a flow straightener and causes a turbulent air flow in the air plenum  34  in the form of booth air to flow into the application area  18  with a substantially unidirectional laminar air flow and a substantially uniform flow velocity. In the optimum case, the booth air is a completely unidirectional laminar flow when it flows into application area  18 . The booth air flows into the application area  18  over at least 80% of the width of the application area  18  and substantially over the longitudinal extension of the application area  18 . The flow straightening structure  54  on the booth ceiling  24  also extends or acts over this area. 
     In the present embodiments, a flow straightening structure  54  is formed by a flow mat  56  with a plurality of flow passages  58 , which can be flexible or largely rigid. Irrespective of whether the flow straightening structure  54  is formed as a mat, it comprises a plurality of flow passages in any case. 
     The flow mat  56  is arranged in the air plenum  34  in the embodiments shown in the figures. The flow straightening structure  54 , i.e. here the flow mat  56 , is arranged on the side of the booth ceiling  24  facing the air plenum  34 , in the embodiments shown here therefore on the side of the filter ceiling  36  facing the air plenum  34 . The flow mat  56  thereby abuts the booth ceiling  24  or rather the filter ceiling  36 . In a modification, a distance can also remain between the flow straightening structure  54  and the booth ceiling  24 . The flow mat  56  covers the area of the booth ceiling  24 . 
     In the embodiments shown in the figures, the flow mat  56  is one-piece; in a variation not shown, the flow mat  56  can also be composed of several mat sections. In a modification, the flow straightening structure  54 , in this case the flow mat  56 , can also be arranged on the side of the booth ceiling  24  or rather the filter ceiling  36  that is away from the air plenum  34 . Alternatively, the flow straightening structure  54  can also be integrated into the booth ceiling  24 . For this purpose, in the present configurations, for example, the filter ceiling  36  and the flow mat  56  can be combined to form the booth ceiling  24  by filling the individual flow passages  58  of the flow mat  56  with a suitable filter material. The flow mat  56  can also be used as a support for a filter ceiling  36 . 
     The flow straightening structure  54  is configured as a honeycomb grid in the present embodiments and defines a honeycomb structure  60 , which is only shown in  FIG. 1  in an enlargement and in which the flow passages  58  have a corresponding hexagonal cross-section. However, cross-sections of the flow passages  58  which deviate from this are also possible, in particular rectangular, especially square, as well as circular or elliptical cross-sections. In general, cross-sections other than hexagonal polygonal cross-sections or otherwise curved walls of the flow passages  58  can also be formed. Various flow passages  58  with different cross-sections and dimensions can also be combined with each other in the flow straightening structure  54 . 
     The flow mat  56  with honeycomb structure  60  can, for example, have a honeycomb diameter between approximately 3 mm and approximately 20 mm and a height between approximately 3 mm and approximately 300 mm. The flow mat  56  with honeycomb structure  60  can be made of a metal or a metal alloy, especially of aluminium. Alternatively, the flow mat  56  with honeycomb structure  60  can be made of fibre composites, for example of aramid paper impregnated with phenolic resin. Other materials are plastics, in particular plastics such as polycarbonates or polyetherimides. In the case of a flow mat  56  made of polycarbonate, a good homogenization of the booth air flow could be achieved when a honeycomb diameter between approximately 3.5 mm and approximately 7 mm with a height of 3 mm to 300 mm was chosen. A honeycomb diameter of approximately 4.2 mm at a height between 5 mm and 300 mm was particularly effective with a flow mat  56  made of a polyetherimide. 
     The air system  46  is configured such that the air plenum  34  is supplied with conditioned air from the side in relation to the longitudinal direction of the coating booth  10 . For this purpose, the plenum housing  38  has multiple supply air passages  62  in the plenum side walls  40 , which supply air passages  62  are connected to a supply system  64  of the air system  46 . As can be seen in  FIG. 4 , the multiple supply air passages  62  are arranged evenly spaced along the plenum side walls  40 . 
       FIGS. 1 to 3  illustrate that all supply air passages  62  of each plenum side wall  40  are connected as a group to one supply air channel  66  of the supply system  64  in each case. The supply air channels  66  are fed with conditioned supply air; for the sake of clarity, the components and parts required for this, which are known in and of themselves, such as fans, lines, valves and the like, as well as preceding conditioning devices, are not shown. 
     The passage cross-sections of the supply air passages  62  of the plenum housing  38  can be adjusted by means of adjusting means  68 , so that the supply air passages  62  can be either blocked or opened up to a maximum passage cross-section. In the present embodiments, the adjusting means  68  are configured as sliders. Generally, pressure losses and pressure differences in the air plenum  34  are compensated for by manually adjusting all adjusting means  68  when the coating booth  10  is installed. 
     The adjusting means  68  can also be adjusted by a motor. The adjusting means  68  can then be controlled individually or in control groups by means of a control unit not shown separately. In this way, pressure losses or pressure differences in the air plenum or over the area of the application area  18  can be compensated. The flow profile of the booth air downstream of the booth ceiling  24  can be measured with a flow sensor technology not shown here, which communicates with the control unit. In this case it is possible to establish a feedback between the actual flow conditions and the flow setting. 
     The booth air now flows as a substantially unidirectional laminar flow from the air plenum  34  into the application area  18 , flows through this area and then flows as booth air loaded with overspray into the lower plant part  48  and there initially into a relaxation area  70 , which extends along the longitudinal extension of the application area  18 . The booth air loaded with overspray is guided via this relaxation area  70  to a separating device  72 , which is located in a separating area  74  of the lower plant part  48 , the separating area  74  adjoining the relaxation area  70  in terms of flow. 
     Thus, a coating booth  10  basically comprises an air supply space  34 , an application area  18 , a relaxation area  70  and a separating area  74 . 
     In order to prevent or at least reduce swirling and cross flows in the application area  18 , the parts and components of the conveyor system  28  can be provided with flow-impermeable covers. 
     The relaxation area  70  is configured as a guide channel  76  of the flow guiding device  52 , which opens at its underside into several suction channels  78 , which in turn each end in a connecting piece  80 . In the present embodiments, the guide channel  76  has a constant cross-section in the downward direction and ends in a flat, horizontal floor with the suction channels  78 . In the case of a variation not shown here, the guide channel  76  can also be tapered downwards towards the suction channels  78 . 
     The separating device  72  comprises several filter devices  82 , one of which is each connected to a connecting piece  80  of the guide channel  76 . In the embodiments shown in  FIGS. 1 and 2 , the filter devices  82  are configured as disposable filter modules  84  of a first type and are used and exchanged as a constructional unit. In the embodiment according to  FIG. 3 , the filter devices  82  comprise a stationary filter housing  86 , in which exchangeable disposable filter modules  88  of a second type are received. In both embodiments according to  FIGS. 1 and 2 or 3  respectively, the filter devices  82  can also be used in the coating booths  10  shown in  FIG. 3 or 1  respectively and  2 . 
     The suction channels  78  extend over about 20% to 30% of the width of the application area  18  and have a substantially square cross-section in the vertical direction. In the longitudinal direction of the application area  18 , the suction channels  78  are provided at intervals so that the filter devices  82  can be positioned as close together as possible. 
     In the disposable filter modules  84  or  88 , the booth air loaded with overspray flows through a filter unit with a filter structure on which the paint overspray is separated. In total, each disposable filter module  84  or  88  respectively is configured as an exchangeable unit. 
     The booth air, now substantially freed of overspray particles, flows from the filter devices  82  into an intermediate channel  90  in each case, via which it then enters a collective flow channel  92 . 
     The booth air can be fed via the collective flow channel  92  to a further processing and conditioning and then, in a circuit not shown here, can be fed as conditioned air into the supply air channels  66  of the supply system  64  and thus into the air plenum  34 , from where it flows back into the application area  18  from above. 
     If the booth air is indeed not yet sufficiently freed from overspray particles by the existing filter devices  82 , further filter stages  94  can be installed downstream of the filter devices  82 , to which the booth air is fed and in which, for example, electrostatic separators are also used, as are known in and of themselves. Such further filter stages can be provided in or in combination with the intermediate channels  90 , for example. 
     Each disposable filter module  84  or  88  respectively is configured to take up a maximum quantity of paint, i.e. a limit load of overspray, depending on the build type of the disposable filter module  84  or  88  and the materials used for it. The quantity of paint already taken up can be monitored using a scale not shown specifically or determined by means of a differential pressure determination. The greater the load of the disposable filter module  84 ,  88  is, the greater the air resistance built up by the disposable filter module  84  or  88 . 
     When a disposable filter module  84  or  88  reaches its maximum take-up capacity, the fully loaded disposable filter module  84  or  88  is moved out of the lower plant part  48  of the coating booth  10 . 
     Each disposable filter module  84  of the first type forms a filter device  82 , i.e. one that can be moved as a unit, for example, with the aid of a lifting vehicle  96  that is operated by an operator  98 , as illustrated in  FIGS. 1 and 2 . For this purpose, the floor portion of the disposable filter module  84  or the filter device  82  formed by the disposable filter module  84  of the first type can be configured in its geometry and dimensions as a standardized support structure and, for example, according to the specifications of a so-called Euro pallet. 
     The depicted worker  98  with the lifting vehicle  96  is only intended to illustrate the manual work, without being shown true to scale. 
     The disposable filter modules  88  of the second type loaded with overspray are removed from the stationary filter housing  86  by a worker  98  and replaced by an unloaded disposable filter module  88 . Alternatively, the filter housing  86  can also be movable and removed from the separating area  74  in order to replace one or more disposable filter modules  88  elsewhere. 
     Prior to this, the flow connection to the relevant filter device  82  with the guide channel  76  is closed by means of gate valves not shown specifically. This gate valve diverts the booth air to the filter devices  82  located next to the disposable filter module  84  or  88  to be exchanged, which assume its task until the replacement has been performed. 
     Then an empty, i.e. not loaded with overspray, disposable filter module  84  of the first type is placed in the operating position or an empty disposable filter module  88  of the second type is placed in the stationary filter housing  86  until it is seated in a flow-tight manner. The gate valve to the guide channel  76  is moved back to an open position so that the newly positioned disposable filter module  84  or  88  is flowed through by the booth air. 
     In a modification not shown, the replacement of one of the disposable filter modules  84  or  88  can be performed in an automated or at least semi-automated fashion. 
     The air system  46  comprises several conveying fans  100  arranged downstream of the filter devices  82 . In the embodiments described here, one conveying fan  100  respectively is arranged at the transition of each intermediate channel  90  to the collection flow channel  92 . The conveying fans  100  support the flow of the booth air through the application area  18  and form secondary conveying fans, which operate as a supplement to a primary conveying system of the air system  46  usually formed by a central fan device. Such secondary conveying fans  100  support in particular the removal of the booth air loaded with overspray from the relaxation area  70 , whereby undesirable flows in the longitudinal direction of the coating booth  10  in the relaxation area  70  are at least reduced. The conveying power of the secondary conveying fans  100  can be controlled in coordination with the loading of the filter equipment  82 . 
     If necessary, such supplementary secondary conveying fans  100  can also be dispensed with. Alternatively, such conveying fans  100  could also form the overall conveying system of the air system  46 , which in this case is configured in a decentralized manner. 
     Such conveying fans  100  can be equipped with sensor technology or work together with sensor technology with which the flow pressure of the booth air flowing through the individual filter devices  82  can be detected. The conveying power of each conveying fan  100  can then be regulated with the associated control system depending on the local conditions and requirements. 
     With such conveying fans  100 , the relaxation area  70  can manage with less height, since the flow is directed and homogenized by the active additional suction. 
       FIGS. 2 and 3  each show the coating booth  10  with a modified flow guiding device  52  comprising a flow guiding structure  102  in addition to the flow straightening structure  54 . 
     In the embodiments shown here, the flow guiding structure  102  is upstream of the flow straightening structure  54  and has the task of guiding the air supplied to the air plenum  34  in the direction towards the flow straightening structure  54  and of effecting a pre-calming of the flow as best as possible. For this purpose, the plenum housing  38  is divided in a first approach by the flow guiding structure  102  in the longitudinal direction into two sub-spaces  38 A,  38 B, into which air flows in each case through the supply air passages  62  in the plenum housing  38 . The two sub-spaces  38 A,  38 B are symmetrical to the central longitudinal axis of the air plenum  34 . 
     This prevents the two air flows, which enter the air plenum  34  from both sides through the supply air passages  62  and thereby flow towards each other, from meeting in the air plenum  34 , which can lead to sometimes violent swirling and turbulence, which may not be sufficiently homogenized by the flow straightening structure  54 . 
     The flow guiding structure  102  shown in  FIG. 2  is configured in the form of two flow baffles  104 , each of which extends from the plenum side walls  40  from above the supply air passages  62  to the center in the longitudinal direction of the air plenum  34 , where they abut the flow straightening structure  54 . The flow baffles  104  extend in the longitudinal direction over the entire air plenum  34 . On its way from the side to the center of the plenum, i.e. in the direction perpendicular to the longitudinal direction of the booth, the incoming air is already calmed at the flow baffles  104  and is moderately successively deflected towards the flow straightening structure  54  by the flow baffles  104 . The flow straightening structure  102  shown in  FIG. 3  is in the form of a vertical intermediate wall  106  extending longitudinally between the end faces of the plenum housing  38 . 
     Other configurations of the flow guiding structure  102  can be provided and also, for example, flow guiding plates can be combined with the intermediate wall  106 . 
     When considering the overall build height of a coating booth  10 , reference is usually made to the ratio of the height of the application area  18  to the total height of the coating booth  10 . The height of the application area  18  is thereby defined by the distance between the booth ceiling  24  and the booth floor  26 . The total height of the coating booth  10  is defined by the distance between the top of the air plenum  34  and the set-up surface of the coating booth  10 . Any superstructures that may be present outside on the top of the plenum housing  38  are to be neglected. 
     The flow straightening structure  54  now makes it possible that the vertical extension of the air plenum  34  can be considerably reduced compared to coating booths known on the market, as explained at the beginning. 
     As a result, the height of the application area  18  can be approximately 50% to 75% of the total height of the coating booth  10 . 
     The height of the air plenum  34  from the plenum ceiling  42  of the air plenum  34  to the booth ceiling  24  can be 5% to 25% of the height of the application area  18 . 
     The vertical extension of the relaxation area  70  can also be reduced. The height of the relaxation area  70  between the booth floor  26  and the separating area  74  can be 5% to 25% of the height of the application area  18 . 
     The vertical extension of the separating area  74  can also be reduced. The height of the separating area  74  between the relaxation area  70  and the set-up surface of the coating booth  10  is at least less than 50% of the height of the application area  18 . 
     The application area  18  of the coating booth  10  can be divided in the longitudinal direction into several application zones, which can either be spatially separated or openly connected to each other and in which different application processes are performed. For example, a top coat and a clear coat can be applied in two application zones in consecutive processes. 
     The separating area  74  can also be divided into several separating zones in the longitudinal direction of the coating booth  10 , which can each be defined, for example, by one or more adjacent filter devices  82 . 
     One or more such separating zones can then be assigned to a respective application zone. The air plenum  34  can also be divided into several plenum spaces in the longitudinal direction of the coating booth  10 , so that, if necessary, each application zone can be supplied individually with booth air with a defined flow. 
     If several application zones are present, all of them can be fluidically connected to the relaxation area  70 . It is possible, in the case of several application zones or only a single application area  18 , that the relaxation area  70  is divided into two or more relaxation zones by one or more transverse partitions. If necessary, the transverse partitions can be provided with air passages, whose passage cross-section can also be adjustable so that the formed relaxation zones remain fluidically connected to each other. Such transverse partitions can at least reduce undesired flows in the longitudinal direction of the coating booth  10  and can be provided as an alternative or supplement to any secondary conveying fans  100  that may be present. 
     Such expansion zones can then in turn be fluidically connected with one or more separating zones or one or more filter devices  82  respectively.