DEVICE FOR SEPARATING OVERSPRAY

Abstract

A device for separating overspray from overspray-laden booth air of surface treatment installations, having at least one separating unit through which overspray-laden booth air can be guided and in which overspray can be separated, wherein the separating unit has a filter device with at least a first and a second filter element and also a first and a second structural element of planar design, wherein the structural elements have through-openings through which the booth air can flow, and wherein the through-openings of the first and of the second structural element are arranged in the flow direction such that the through-openings are not completely aligned with one another in the flow direction.

Claims

1. A device for separating overspray from overspray-laden booth air of surface treatment installations, comprising: a) at least one separating unit through which overspray-laden booth air can be guided and in which overspray can be separated, wherein b) the at least one separating unit has a filter device with at least one filter element and also a first structural element and a second structural element which are of planar design, wherein c) the first structural element and the second structural element each have through-openings through which booth air can flow, and wherein d) the through-openings of the first and of the second structural element are arranged in a flow direction such that the through-flow openings are not completely aligned with one another in the flow direction.

2. The device according to claim 1, wherein the through-openings of the first and of the second structural element are arranged with respect to one another such that through-flowing booth air is guided such that an inertial filter effect occurs.

3. The device according to claim 1, wherein the at least one filter element has a first structural element and a second structural element.

4. The device according to claim 3, wherein, as seen in the flow direction, the at least one filter element has a depth filter element between the first structural element and the second structural element.

5. The device according to claim 4, wherein the depth filter element contains an additive which supports particle agglomeration.

6. The device according to claim 1, wherein the at least one filter element has a frame structure which is connected to the first and/or second structural element.

7. The device according to claim 6, wherein the frame structure is formed integrally with the first and/or the second structural element.

8. The device according to claim 1, wherein the at least one filter element has a depth filter and as seen in the flow direction, the first structural element, the depth filter element and the second structural element of the at least one filter element are connected to one another in a sandwich-like manner.

9. The device according to claim 1, wherein the at least one separating unit has a receptacle for one or more filter elements.

10. The device according to claim 1, wherein a first filter element and a second filter element are provided.

11. The device according to claim 10, wherein the first filter element has a different filter characteristic than the second filter element.

12. The device according to claim 11, wherein the separating unit has at least three filter elements with different filter characteristics.

13. A coating installation for coating vehicle body components having a device according to claim 1.

14. A method for treating overspray of a coating installation comprising the step of using a device according to claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Exemplary embodiments of the invention will be explained in more detail below with reference to the drawings, in which:

[0032] FIG. 1 shows in a schematic cross-sectional view a painting booth having a separating unit for overspray in which booth air is guided via an air-guiding device to a separating device;

[0033] FIG. 2 shows in a perspective partial cutaway view an embodiment of a filter element according to the invention; and

[0034] FIGS. 3-5 show in schematic perspective views different embodiments of filter modules.

DESCRIPTION OF PREFERRED EXEMPLARY EMBODIMENTS

[0035] While this invention is susceptible to embodiments in many different forms, there is described in detail herein, preferred embodiments of the invention with the understanding that the present disclosures are to be considered as exemplifications of the principles of the invention and are not intended to limit the broad aspects of the invention to the embodiments illustrated.

[0036] FIG. 1 shows a coating booth 10 and also a surface treatment installation which is designated overall by the reference sign 12 and in which objects 14 are painted. Vehicle bodies 16 are shown as an example of objects 14 to be painted. Before they reach such a coating booth 10, they are for example cleaned and degreased in pretreatment stations (not shown separately). After the coating operation, various post-treatments, such as, for example, drying, take place.

[0037] The coating booth 10 comprises, arranged at the top, a coating or painting tunnel 18 which is delimited by vertical side walls 20 and a horizontal booth ceiling 22, but is open at the end sides. Moreover, the painting tunnel 18 is open in such a way that overspray-laden booth air can flow downward. The booth ceiling 22 customarily forms a lower boundary of an air supply chamber 24 and takes the form of a filter ceiling 26. The vehicle bodies 16 are transported from the inlet side of the coating tunnel 18 to its outlet side by a conveying system 28 known per se which is accommodated in the coating tunnel 18. Situated in the interior of the coating tunnel 18 are application devices 30 in the form of multi-axis application robots 32, as are likewise known per se. The vehicle bodies 16 can be coated with the corresponding coating material by means of the application robots 32. This coating operation gives rise to overspray which, as already mentioned, is to be downwardly carried away.

[0038] To the bottom, the coating tunnel 18 is open via a walk-on grating 34 toward an installation region 36 arranged therebelow. In this installation region 36, the overspray particles carried along by the booth air are separated from the booth air.

[0039] For this purpose, air flows out of the air supply chamber 24 during a coating operation downwardly through the coating tunnel 18 to the installation region 36. Here, the air takes up paint overspray present in the coating tunnel 18 and carries it along with it. This overspray-laden air is guided by means of an air-guiding device 38 to a separating device in the form of one or more filter modules 40.

[0040] For this to occur, the air-guiding device 38 comprises, in the exemplary embodiment shown in FIG. 1, a guide duct 42 which is formed by guide plates 44 which extend inwardly and downwardly at an inclination from the side walls 20. The guide duct 42 opens at the bottom into a plurality of connection ducts 46 which for their part terminate at the bottom in a connection nozzle 48.

[0041] During a coating operation, each filter module 40 is fluidically and releasably connected to the air-guiding device 38. In the filter module 40, the booth air flows through one or more filter elements at which the paint overspray is separated. This will be discussed in detail below. Overall, each filter module 40 is designed as an exchangeable structural unit and can, where appropriate, also be configured as a disposable filter module.

[0042] The booth air which is largely freed of overspray particles after being filtered by the filter module 40 flows out of the filter module 40 into an intermediate duct 50 via which it passes into a collecting flow duct 52. The booth air is fed via the collecting flow duct 52 for further processing and conditioning. Subsequent thereto, the conditioned booth air is guided in a circuit (not shown separately) into the air supply chamber 24 again from which it flows again from above into the coating tunnel 18.

[0043] If the booth air is still not sufficiently freed of overspray particles by the filter modules 40 present, yet further filter stages can be arranged downstream of the filter modules 40. These filter stages are fed with the air flowing off from the filter modules 40. Electrostatically operating separators, as are known per se, can also be used there, for example.

[0044] As is already indicated in FIG. 1 and will be explained more precisely below, the filter module 40 has a plurality of filter elements 100-102 through which the booth air to be purified can successively flow. The course of the flow in the installation region 36 is symbolically illustrated by the arrows 54, 56.

[0045] FIG. 2 shows the construction of such a filter element 100 by way of an exemplary embodiment. In the position shown in FIG. 2, flow passes through the filter element 100 from the rear to the front, as illustrated by the arrow A. There correspondingly appears an inflow side 103 and an outflow side 105. The filter element 100 has a first perforated plate 107 on the inflow side and a second perforated plate 109 on the outflow side.

[0046] The first perforated plate 107 has substantially square through-openings 111, and the second perforated plate 109 has substantially circular through-openings 113. The two types of through-openings 111, 113 are arranged in a matrix-like manner. In the present embodiment, the number of inflow-side through-openings 111 corresponds to the number of outflow-side through-openings 113 both in terms of number and substantially in terms of arrangement. In alternative embodiments, in order to reinforce the inertial filter effect it would be alternatively or additionally possible to provide both, on the outflow side, a different number of through-openings or a different geometrical shapepreferably a smaller numberand also, alternatively or additionally, to provide a different arrangement of the through-openings.

[0047] The inflow-side first perforated plate 107 and the outflow-side second perforated plate 109 are connected to one another via a frame 115. The frame 115 is arranged within the outer peripheral edges of the first and the second perforated plate 107, 109 and thus forms a uniform spacing between the perforated plates 107, 109. The first and the second perforated plate 107, 109 are thus situated substantially parallel to one another. In the embodiment shown in FIG. 2, the interspace situated between the two perforated plates 107, 109 is filled with a filter material 117. The filter material 117 can, for example, take the form of a woven fabric, knitted fabric, filament, random-laid mat, nonwoven, etc.

[0048] During a flow through the through-openings 111 of the first inflow-side perforated plate 107, the air flow arising at the perforated plate 107 is divided between the available number of through-openings 111 corresponding to the shape and position. Since the outflow-side perforated plate 109 has differently shaped through-openings 113, the air flow, which spreads out further after the first perforated plate 107, is forced to carry out movements parallel to the plane of the perforated plates 107, 109. An inertial separation takes place during this movement. The resultant filter effect is supported and reinforced by the presence of the filter element 117 which acts as a depth filter. Two filter effects are thus combined at one location. This results in a particularly efficient separation of the overspray situated in the air flow.

[0049] In a development of the embodiment shown in FIG. 2, there can be provision that the filter fabric 117 is provided with an additive, such as, for example, industrial petroleum jelly. Such an additive can, on the one hand, adapt the effectiveness of the inertial/depth separation to the currently occurring overspray and at the same time improve the service life of the filter element. The additive results in a higher binding/adhesion of the particles to the filter material 117 of the filter element 100. Particularly in the case of dusty paints, there is frequently to be observed an entrainment effect of the paint particles as a result of abrasion. Here, already deposited particles are detached again by newly impinging particles and entrained. This can be prevented or reduced by the addition of an additive.

[0050] FIGS. 3-5 show different configurations of how filter elements 100-102 can be arranged in and/or removed from a filter module 40.

[0051] In the configuration shown in FIG. 3, the filter modules 100-102 are situated approximately at the same spacing from one another within the filter module 40. The filter module 40 has a filter module housing 60 which delimits a filter housing interior 62 which extends between a module inlet 64 and a module outlet 66 and through which the booth air flows. This is illustrated by the arrow A.

[0052] The module housing 60 comprises a bottom part 70 which, in the present exemplary embodiment, is designed in its configuration as a standardized supporting structure, for example according to the specification of a euro pallet. Accordingly, the arrangement of a plurality of filter modules in the installation region 36 of the coating booth 10 can occur according to a grid which is based on the standardized bottom part 70 used.

[0053] A lower collecting region of the filter module 40 is liquid-tight and in this way designed as a collecting trough 72 for coating material which separates in the filter module 40 and flows off downwardly.

[0054] In the filter space 62 there is arranged a holding frame 74 which is designed for holding the filter elements 100-102. The holding frame 74 encompasses a filter space 78 within which the actual filtering of the inflowing and overspray-laden booth air takes place. During the filtering process, the booth air flows along a main flow direction A through the filter space 78 and in so doing strikes the filter elements 100-102. Following the filtering already described above, the thus purified air passes out of the filter module 40 at the module outlet 66 and leaves said module.

[0055] In the embodiment shown in FIG. 3, the individual filter elements 100-102 can be introduced into the filter space 78 from above and can be fastened to the holding frame 74, for example by being slid in. For this purpose there can be provided, for example, lateral guide grooves, holding clamps, screw connections, adhesive connections or the like. The filter elements 100-102 are arranged equidistantly and thus have equally wide interspaces in which the air flow can even out again between the individual filtering processes. A separation can thus take place not only within the filter elements 100-102. Rather, given a corresponding configuration of the perforated plates of the individual elements 100-102, a deflection of the outflow can also take place between the individual filter elements, which in turn can lead to an inertial separation. For example, the outflow-side perforated plate 109 of the filter element 100 can have a higher number of through-openings 113 than the inflow-side perforated plate of the filter element 101 situated on the outflow side. Alternatively or in addition, the shape and/or the arrangement of the through-openings can also be different.

[0056] An alternative is illustrated in FIG. 4. The filter elements 100-102 there are arranged in direct contact with one another. The advantage of this arrangement lies in the fact that, although no separate inertial separation takes place between the individual filter elements 100-102 and thus the advantage of an additional separation is dispensed with, at the same time the filter effect is thus less dependent on the flow velocities between the individual filter elements 100-102 and is thus more predictable.

[0057] FIG. 5 shows an embodiment in which the filter elements 100-102 can be slid in and exchanged via laterally incorporated slots 80 in the filter module 40. This facilitates the maintenance and the exchange of the filter elements 100-102.

[0058] In one embodiment, which is not illustrated in the figures, one or more filter elements can also be positioned below the grating 34, at the beginning of the installation region 36for example horizontally, at the beginning of the guide duct 42 and/or at the beginning of the filter device 40.

[0059] While this invention is susceptible to embodiments in many different forms, there is described in detail herein, preferred embodiments of the invention with the understanding that the present disclosures are to be considered as exemplifications of the principles of the invention and are not intended to limit the broad aspects of the invention to the embodiments illustrated.