DE102010051085A1 - Method and device for separating overspray and installation with such - Google Patents

Abstract

A method is specified for separating overspray from the booth exhaust air laden with overspray from coating systems, in particular painting systems, in which the overspray is absorbed by an air stream and fed to an electrostatically operating separation device (38), where a large part of at least the solids from the Overspray is deposited on at least one separation surface (42) on which a release agent is applied. A layer of ice (62) is produced as a separating agent on the at least one separation surface (42). A separating device (38) with a layer of ice (62) and a system for coating objects (4), in particular vehicle bodies, are also specified.

Description

The invention relates to a method for separating overspray from the overspray-laden car exhaust air of coating systems, in particular paint systems, in which the overspray is taken up by an air stream and passed to an electrostatic working separation device where a majority of at least the solids from the overspray at least a separation surface is deposited, on which a release agent is applied.

• a) wenigstens einer Abscheidefläche, an welcher die Kabinenabluft entlang führbar ist und welche mit einem Pol einer Hochspannungsquelle verbunden ist;
• b) einer im Luftstrom angeordneten Elektrodeneinrichtung, welche der Abscheidefläche zugeordnet und mit dem anderen Pol der Hochspannungsquelle verbunden ist.

In addition, the invention relates to a device for separating overspray from the overspray-laden cabin exhaust air from paint shops

• a) at least one separation surface, on which the cabin exhaust air is guided along and which is connected to a pole of a high voltage source;
• b) a arranged in the air flow electrode means which is associated with the Abscheidefläche and connected to the other pole of the high voltage source.

• a) einer Beschichtungskabine, in welcher die Gegenstände mit Beschichtungsmaterial beaufschlagbar sind und durch welche ein Luftstrom geleitet werden kann, der entstehende Overspraypartikel des Beschichtungsmaterials aufnimmt und abführt;
• b) einer elektrostatisch arbeitenden Abscheidevorrichtung.

Furthermore, the invention is concerned with a system for coating, in particular for painting objects, in particular vehicle bodies, with

• a) a coating booth in which the articles can be exposed to coating material and through which an air stream can be passed, which receives and removes resulting overspray particles of the coating material;
• b) an electrostatic working separation device.

In the case of manual or automatic application of lacquers to objects, a partial flow of the lacquer, which generally contains both solids and / or binders and solvents, is not applied to the article. This partial flow is called "overspray" in the professional world. In addition, the terms overspray, overspray particles or overspray solids are always understood to mean a disperse system, such as an emulsion or suspension or a combination thereof. The overspray is detected by the air flow in the paint booth and fed to a separation, so that the air can be optionally returned to the coating booth after a suitable conditioning.

Especially in systems with greater paint consumption, for example in systems for painting vehicle bodies, preferably wet separation systems are used. In the case of wet separators known from the market, water flows together with the exhaust air from the cabin to an air flow accelerating nozzle. In this nozzle there is a turbulence of the flowing cabin exhaust air with the water. During this process, the overspray particles largely pass into the water, so that the air leaves the wet scrubber substantially cleaned and the overspray paint particles are de-adhesive in the water. From this they can then be recovered or disposed of.

In known wet scrubbers relatively much energy is required to circulate the required quite large amounts of water. The treatment of the rinse water is costly due to the high use of paint-binding and detackifying chemicals and the Lackschlammentsorgung. Furthermore, the air absorbs a lot of moisture due to the intensive contact with the rinse water, which in turn results in a high energy consumption for the air treatment in the recirculation mode.

In known from the market devices of the type mentioned in contrast is deposited dry way by ionized by the passing cabin exhaust air entrained paint Overspraypartikel by the electrode means and migrate due to the built-up between the Abscheidefläche and the electrode device electric field to Abscheidefläche, at which they separate. The adhering to the separation surface paint Overspraypartikel can then, for example, mechanically stripped and transported away from this.

The cleaning effect of such separators is very high. For continuous operation, however, it must always be ensured that a sufficiently strong electric field can form between the deposition surface and the electrode device, which is possible only up to a certain layer thickness of paint overspray on the deposition surface, since such a layer has an insulating effect , However, the required continuous removal of the paint overspray from the separation surface is associated with structurally quite complex measures and can be prone to failure. It may also happen that overspray on the Abscheidefläche so reacts, hardens or dries, so that it can not be removed by simply stripping the Abscheidefläche.

Object of the present invention is therefore to provide a method, a separation device and a system of the type mentioned, which take into account these problems.

This object is achieved in the method of the type mentioned in that as Release agent on the at least one Abscheidefläche an ice sheet is generated.

According to the invention, therefore, ice is used as the separating layer between the separation surface and the overspray so that it can not come into direct contact with the separation surface. The use of ice as such a separation layer is based on the recognition that an ice layer on the separation surface does not disturb the electric field and can be removed from the separation surface with relatively simple means together with overspray particles, if necessary.

It is advantageous if, after a working period, an ice layer with deposited solids present on the at least one separation surface is removed and a fresh layer of ice is produced on the at least one separation surface. In this way, it is possible to dispense with continuous stripping of the overspray. The working period may be about 2 hours, about 4 hours, about 6 hours, about 8 hours, about 10 hours, or about 12 hours. With lower loading of the release agent with overspray and a longer work period of up to several days is possible, as long as the insulation effect of the overspray does not affect the formation of the field lines so that proper operation of the separator is no longer possible.

It is advantageous if a surface area of a deposition plate is used as the deposition surface.

Advantageously, the surface of the deposition plate can be effectively cooled using a deposition plate comprising one or more Peltier elements. Peltier elements are known from the prior art. The cooling side of the Peltier element (s) may themselves form the surface of the deposition plate. Alternatively, the one or more Peltier elements may be connected to the deposition plate such that their surface cools.

Alternatively or in addition to the use of Peltier elements, it is also advantageous if a cooling medium is passed through the separation plate.

In this case, it has proved to be particularly advantageous if, for producing the ice layer on the at least one separation surface cooled cooling medium is passed through the Abscheideplatte to cool the Abscheideplatte such that water from the deposition of the surrounding the atmosphere as an ice layer on the at least one Precipitation surface precipitates.

To remove an ice layer with separated solids from the at least one separation surface then advantageously heated cooling medium can be passed through the separation plate to heat the separation plate such that ice melts on the at least one separation surface at least on the separation surface facing side of the ice layer. Thus, a largely contiguous and overspray-loaded layer of ice on a film of water from the separation surface slip down. If one or more Peltier elements are present, they can either be deactivated or reversed by reversing the current direction, so that their previously cooling side is heated.

A compression refrigeration cycle can be conveniently established when the cooling medium is circulated in a circuit with a compressor device and an evaporator device during the production of the ice layer.

In such a compressor unit, cooling medium is compressed, whereby it heats up. At least part of the heat energy stored in the cooling medium can be used to advantage when it is passed between the compressor device and the evaporator device through the heat exchanger coil of a heat exchanger.

For example, when the solids exhausted cabin air is passed through this heat exchanger, the heat energy of the cooling medium can be used to dry that cabin air. The dried cabin air can then, if appropriate after further conditioning, be recirculated to a corresponding paint booth.

In a development, the separation surface can be freed of ice in a favorable manner, by passing the cooling medium for heating the at least one deposition surface coming from the compressor device past the evaporator device to the separation plate. This is possible for example by a simple bypass line.

It is also advantageous if the cooling medium is also guided past the heat exchanger.

• c) eine Eisschicht als Trennmittel auf der wenigstens einen Abscheidefläche erzeugt ist.

In a device of the type mentioned above, the above object is achieved in that

• c) an ice layer is produced as a release agent on the at least one separation surface.

With regard to the ice layer and the developments explained below, the statements made above regarding the method apply mutatis mutandis.

The device advantageously comprises a device by means of which a fresh layer of ice can be produced on the at least one separation surface and / or an ice layer with precipitated solids present on the at least one deposition surface can be removed.

It is favorable if the at least one separation surface is a surface region of a deposition plate. This can advantageously comprise one or more Peltier elements.

Alternatively or additionally, a cooling line, through which a cooling medium can be passed, preferably runs in the interior of the separation plate.

As explained above, a compression cooling circuit can be conveniently established when the cooling medium is at least temporarily conductible in a circuit with a compressor device and an evaporator device, which is connected to the cooling line.

It is also advantageous if a heat exchanger with a heat exchanger coil is arranged between the compressor device and the evaporator device, through which coolant coming from the compressor device can be conducted.

Preferably, then a flow path of the freed of solids cabin air through the heat exchanger.

Moreover, it is advantageous if a switchable via valves bypass line is present, via which the cooling medium at least temporarily from the compressor device coming to the evaporator device over to the cooling line of the deposition plate is conductive.

Here, it may be favorable if the bypass line runs in such a way that the cooling medium can also be conducted past the heat exchanger to the cooling line of the separation plate.

• c) die elektrostatische Abscheidevorrichtung nach einem der Ansprüche 13 bis 22 ausgebildet ist.

In the above-mentioned system, the above-mentioned object is achieved in that

• c) the electrostatic precipitation device according to one of claims 13 to 22 is formed.

The plant according to the invention thus comprises a separation device with one or more of the features mentioned above for the device. The advantages that can be achieved correspond to the advantages explained above for the method and the device.

Embodiments of the invention are explained below with reference to the drawings. In these show:

1 a spray booth of a surface treatment plant with an overspray separator in a front view;

2 a perspective view of four deposition units and four electrode devices of the separator of 1 ;

3 a schematic illustration of a meandering cooling line in a separation plate of a separation unit;

4 a schematic representation of the paint booth, which is shown with three separation plates, a circulation system for a cooling medium and an air circulation of the cabin air;

5 one of the 4 corresponding representation in which a first circuit of the circulation system for cooling the Abscheidplatten is shown highlighted;

6 another one 4 corresponding representation in which, however, a second circuit of the circulation system for heating the Abscheidplatten is shown highlighted;

7 again one of the 4 corresponding representation in which, however, the air circulation of the cabin air is shown highlighted;

8th one of the 2 corresponding view of four separation units, wherein the separation units have separating plates which comprise Peltier elements;

9 schematically a section through Abscheideeinheiten with Peltier elements, wherein the respective section through a Abscheideplatte a section along the section line IX-IX in 3 and two separation plates are shown at the ends of the separator and interposed separator plates.

First, on the 1 and 2 Referenced. There is with 2 overall a painting booth a surface treatment plant referred to, in which vehicle bodies 4 to be painted after being in the paint booth 2 upstream, not specifically shown pretreatment stations z. B. were cleaned and degreased. The paint booth 2 resting on a steel structure 6 as it is known in and of itself.

The paint booth 2 includes a topping paint tunnel 8th , which of vertical sidewalls 10 and a horizontal cabin ceiling 12 limited, but at the ends and downwards in such a way is open, that overspray laden cabin exhaust air can flow down. The cabin ceiling 12 is formed in the usual way as the lower boundary of an air supply space (not shown) with filter cover.

Above a lower opening 14 of the paint tunnel 8th is a steel construction 16 arranged, which in itself a known conveyor system 18 bears, which will not be discussed here. With this can be painted vehicle bodies 4 from the input side of the paint tunnel 8th be transported to the output side. Inside the paint tunnel 8th are not specifically shown application facilities, by means of which the vehicle bodies 4 can be coated in a conventional manner with varnish. The lower opening 14 of the paint tunnel 8th is covered by a walk-in grate not specially shown.

Below the spray booth 2 there is a plant area 20 in which the overspray particles carried by the cabin air are separated from the cabin air. The plant area 20 is limited by a housing not provided with a reference numeral, which is in 1 only indicated as a dashed line.

The plant area 20 includes a flow area 22 , which up to the spray booth 2 open and through two baffles 24 and 26 is predetermined, between the upper ends of the cabin opening 14 extends. The baffles 24 . 26 diverge down to one below the flow area 22 arranged separation space 28 through which the cabin air flows in a direction from top to bottom.

The lower cabin opening 14 is also from Abscheideblechen 30 flanked, which are moderately downwards towards the outside and outwardly to a collecting trough 32 are shaped. The Abscheideblechen 30 can a separation liquid from distribution channels 34 be fed, which next to the baffles 24 and 26 are arranged so that the Abscheideflüssigkeit in a largely continuous layer on the Abscheidevlechen 30 to the collecting troughs 32 flows. The separating liquid absorbs a part of the over-air carried by the cabin air, while the cabin air from the paint booth 2 down through the cabin opening 14 in the separation room 28 flows.

From the collecting troughs 32 For example, the separating liquid can be supplied to a cleaning and conditioning process in which it is freed of the paint overspray in a manner known per se. Then, the separation liquid in a circuit back to the distribution channels 34 be supplied.

In the separation room 28 is a separation unit 36 an electrostatic working separation device 38 arranged. The separation unit 36 includes a plurality of in the longitudinal direction of the separation chamber 28 successively arranged rectangular separating plates 40 of which four in 2 are shown. The respective opposite outer surfaces of the separation plates 40 form separation surfaces 42 of which in 2 only in each case to be recognized separation area 42 every separation plate 40 is provided with a reference numeral. The separation plates 40 are stored in a holding frame, which is not shown separately.

In the separation unit 36 are the separation plates 40 arranged parallel to each other in such a way that between them in each case a distance remains sufficient that two adjacent deposition plates 40 in each case an electrode device 44 between them. Of these, only the one in 2 rightmost electrode device provided with reference numerals.

Each electrode device 44 is with a pole of its associated high voltage source 46 connected, of which in 1 only a single is indicated schematically. The separation plates 40 are connected to ground potential across the other pole of the high voltage source. The connection of the electrode device 44 and the separation plate 40 with the high voltage source 46 is in 1 indicated by dashed lines.

In a modification, all electrode devices can also be used 44 powered by a single common high voltage source.

Each electrode device 44 comprises two straight, parallel to each other electrode strips 48 , These hold in a field section 50 the electrode device 44 a grid electrode 52 , whose between the electrode strips 48 extending edges perpendicular to these. In a corona section 54 the electrode device 44 hold the electrode strips 48 several corona wires acting as a spray electrode 56 , The corona wires 56 run in a through the electrode strips 48 given plane perpendicular to these and are arranged at equal distances from each other.

The number of corona wires 56 the electrode device 44 and their distance from each other may vary depending on the deposition behavior of the overspray particles. At present Embodiment are four corona wires 56 per electrode device 44 intended.

As in the 1 and 2 it can be seen have the electrode devices 44 Overall, an extension which approximately the extension of the separation plates 40 the separation unit 36 equivalent.

Below the separation plates 40 is a revolving endless conveyor belt 58 arranged, which in the longitudinal direction of the paint booth 2 and across the separation plates 40 runs and becomes one in the 4 to 7 With 60 designated collection area leads. In the 4 to 7 is a modification of one of several conveyor belts 58 shown which transverse to the longitudinal direction of the cabin 2 and parallel to the separation plates 40 run. Instead of the conveyor belt (s) 58 For example, one can also be used as a collection area 60 downwardly inclined channel or a horizontally extending channel be present, in the latter then z. B. a scratch ensures that the material to the collection area 60 is encouraged.

On both separation surfaces 42 every separation plate 40 is a layer of ice 62 (please refer 2 ), which acts as a release agent and prevents deposited overspray directly at the separation surfaces 42 the separation plates 40 attaches. The ice layers 62 are each between 0.2 mm and 2 mm thick. In practice, has a thickness of ice layers 58 1 mm proved to be useful.

The ice layers 62 be on the separation surfaces 42 generated by the Abscheidplatten 40 be cooled to a temperature of below 0 ° C. If subsequently it is said that a layer of ice 62 is generated, this includes that an already existing ice sheet 62 is maintained.

These are the separation plates 40 formed double-walled, wherein inside each Abscheidplatte 40 in each case a meander-shaped cooling line 64 between an inlet nozzle 66 and an outlet 68 runs, in the present embodiment, on a vertical narrow side of a respective deposition plate 40 are provided. These are in the 1 to 3 to recognize. In 3 is the meandering course of the cooling line 64 illustrated schematically.

The inlet nozzles 66 the separation plates 40 are via supply lines 70 with a distribution block 72 connected, over which each cooling line 64 a certain separation plate 40 a cooling medium is supplied. The outlet nozzle 68 the separation plates 40 are via discharge lines 74 with a collecting block 76 connected, is discharged via the cooling medium, after there is a specific deposition plate 40 flowed through. As a cooling medium so-called refrigerant come into consideration, as they are known in and of themselves; for example, the refrigerant commonly referred to as R134a is tetrafluoroethane. In principle, all non-flammable and non-paint-damaging refrigerants are suitable, which do not cause surface coating defects, if in the event of leakage to the vehicle body 4 should come into contact.

The separation device 38 includes next to the separation unit 36 a circulation system 78 , which with the distribution block 72 and the collecting block 76 is connected and in detail in the 4 to 7 is shown. There are the paint booth 2 with the paint tunnel 8th and the capture area 22 shown only very schematically. From the separator 38 are only three consecutive separation plates 40 illustrated in the manner described above with the manifold block 72 and the collecting block 76 are connected.

The circulation system 78 includes a first fluid conduit 80 that from the collecting block 76 to the inlet of a compressor 82 leads. On the output side is the compressor 82 via a second fluid line 84 with a first end of a heat exchanger coil 86 a heat exchanger 88 connected at the opposite end via a third fluid line 90 with the entrance of an evaporator 92 connected is.

The exit of the evaporator 92 leads via a fourth fluid line 94 to the distribution block 72 ,

The second fluid line 84 is via a first bypass fluid line 96 with the fourth fluid line 94 connected, wherein at the mouth points in each case a valve 98 respectively. 100 is available.

The first fluid line 80 is via a second bypass fluid line 102 with the third fluid line 90 connected between the heat exchanger 88 and the evaporator 92 runs. There is one valve at each discharge point 104 respectively. 106 available.

In addition, the first fluid line 80 via a third bypass fluid line 108 with the second fluid line 84 connected between the compressor 82 and the heat exchanger 88 runs, wherein at each discharge point in each case a valve 110 respectively. 112 is available.

Furthermore, there is the third fluid line 90 between the heat exchanger 88 and the evaporator 92 runs through a fourth bypass fluid line 114 with the fourth fluid line 94 connected. At each discharge point there is again a valve; these bear the reference numerals 116 respectively. 118 ,

Through the valves 104 and 110 is the first fluid line 80 in a first section 80a between the collecting block 76 and the valve 104 , a second section 80b between the valve 104 and the valve 110 as well as a third section 80c between the valve 110 and the compressor 82 divided.

Accordingly, the valves divide 98 and 112 the second fluid line 84 in a first section 84a between the compressor 82 and the valve 98 , a second section 84b between the valve 98 and the valve 112 as well as a third section 84c between the valve 112 and the heat exchanger coil 88 ,

The third fluid line 90 is in an analogous way through the valves 106 and 116 divided into a first section 90a between the evaporator 92 and the valve 106 , a second section 90b between the valve 106 and the valve 116 as well as a third section 90c between the valve 116 and the heat exchanger coil 86 ,

Finally, divide the valves 100 and 118 still the fourth fluid line 94 in a first section 94a between the distribution block 72 and the valve 100 , a second section 94b between the two valves 100 and 118 as well as a third section 94c between the valve 118 and the evaporator 92 ,

Viewed in the flow direction, the first fluid line forms 80 together with the compressor 82 , the second fluid line 84 , the heat exchanger snake 86 , the third fluid line 90 , the evaporator 92 , the fourth fluid line 94 as well as the distribution block 72 , the cooling pipes 64 in the deposition plates 40 and the collecting block 76 a first cycle 120 for cooling medium. This first cycle 120 is in 5 highlighted by the lines shown by solid lines.

The first cycle 120 is formed when the valves 98 . 100 . 104 . 106 . 110 . 112 . 116 and 118 are set to be the flow path through the first circuit 120 release.

By the separation plates 40 Cooling medium through this first cycle 120 are fed, they can be cooled to temperatures below 0 ° C. Because the ice layers 62 To constantly lose heat, the cooling must always be maintained as long as the ice layers 62 on the separation plates 40 to stay educated.

A second cycle 122 for cooling medium is in 6 illustrated by the lines shown by solid lines. The second cycle 122 is viewed in the flow direction through the section 80a the first fluid line 80 , the second bypass fluid line 102 , the section 90a the third fluid line 90 , the evaporator 92 , the section 94c the fourth fluid line 94 , the fourth bypass fluid line 114 , the section 90c the third fluid line 90 , the heat exchanger coil 86 , the section 84c the second fluid line 84 , the third bypass fluid line 108 , the section 80c the first fluid line 80 , the compressor 82 , the section 84a the second fluid line 84 , the bypass fluid line 96 and the fluid line section 94a the fourth fluid line 94 as well as the distribution block 72 , the cooling pipes 64 in the deposition plates 40 and the collecting block 76 educated.

The second cycle 122 is formed when the valves 98 . 100 . 104 . 106 . 110 . 112 . 116 and 118 are set such that the flow path corresponding to the second circuit 122 is released.

By the separation plates 40 Cooling medium through this second circuit 122 is fed, they can be heated again to temperatures above 0 ° C.

In the present embodiment, in each case three-way intersections are formed at all mouth points of the lines and each discharge point is associated with a corresponding valve. In a modification, all may also be one of the first to fourth fluid lines 80 . 84 . 90 and 94 leading bypass fluid lines 96 . 102 . 108 and 114 meet at a common mouth, where then a corresponding four-way valve is provided.

Overall, the circulation system forms 78 in connection with the cooling pipes 64 the separation plates 40 a device by means of which in each case a fresh layer of ice 62 on the separation surfaces 42 generated and / or one each on the Abscheideflächen 42 existing ice layer 62 can be removed with separated solids.

The heat exchanger 88 Cabin air is released from the separation chamber 28 via a flow channel 124 fed, so that the cabin air snake its heat exchanger 86 flows around. The heat exchanger 88 is in a conditioning unit 1126 in which further facilities are provided to condition the cabin air. This is exemplified by a sprinkler 128 illustrates, by means of which the cabin air can be moistened.

For ice formation on the separation plates 40 As a rule, a relative humidity of 60% to 70% of the conditioned cabin air is sufficient. This moisture can z. B. by the sprinkler 128 be effected. The air can still after the cleaning of the above-mentioned application facilities in Lackiertunnel 8th be humidified by spraying water through them.

From the conditioning unit 126 the cabin air flows through a flow channel 130 to the above-mentioned and not specifically shown Luftzuführraum, from where they on the filter cover from the top of the paint tunnel 8th flows.

Thus form the flow channel 124 , the conditioning unit 126 and the flow channel 130 an air circulation 132 the cabin air. This cycle is in 7 again clarified by the lines shown by solid lines.

About a side channel 134 can the from the separation room 28 outgoing cabin air in the flow channel 124 optionally fresh air can be supplied. From the flow channel 130 go a side channel 136 via which a portion of the through the flow channel 130 flowing air can optionally be discharged through the roof.

The spray booth explained above 2 works as follows:
The valves 98 . 100 . 104 . 106 . 110 . 112 . 116 and 118 of the circulation system 78 are initially adjusted so that the cooling medium in the first cycle 120 that flows in 5 is clarified. This is cooling medium in the compressor 82 compressed, where it heats up.

Part of the heat is in the heat exchanger 88 to the cabin air, which is the conditioning unit 126 flows through. After that, the cooling medium in the evaporator 92 brought into a gaseous state, whereby it cools. In the present embodiment, the cooling medium z. B. a temperature of about -6 ° C, after the evaporator 92 as gas has left.

The thus cooled and now gaseous cooling medium now flows into the distribution block 72 and from this to the individual separation plates 40 distributed where it passes through the respective cooling pipes 64 flows The cooling medium withdraws from the separation plates 40 Heat, whereby these cool to a temperature at which water from the in the separation chamber 28 ruling and the deposition plates 40 surrounding atmosphere at the separation areas 42 condensed out and there to the ice layer 62 freezes. Thus, this water is reflected as a layer of ice 62 on the separation surfaces 42 low. In a modification not specifically shown, a sprinkler may also be present, with which the separation plates 40 can be sprayed with water. After the cooling medium a separation plate 40 has flowed through it in the present embodiment z. B. a temperature of about -2 ° C.

If now the vehicle bodies 4 in the painting tunnel 8th be painted, the cabin air located there is loaded with paint Overspraypartikeln. These can still be liquid and / or sticky, but already more or less firm. The car exhaust air laden with paint overspray flows through the lower opening 14 of the paint tunnel 8th in the first flow area 22 of the lower plant area 20 , There, this air is through the baffles 24 . 26 to the separation room 28 directed. Part of the overspray is already absorbed by the Abscheidflüssigkeit on the Abscheidblechen 30 to the collecting troughs 32 flows. The cabin air flows downwards in the direction of the separation unit 36 the separator 36 and continues to flow there between adjacent separation plates 40 therethrough.

At the corona wires 56 the electrode devices 44 it comes in a well-known way to corona discharges through which the overspray particles are effectively ionized in the passing air exhaust cabin.

The ionized overspray particles pass through the deposition plates at ground potential 40 and the intervening grid electrodes 52 in the field section 50 the electrode devices 44 , Due to the between grid electrode 52 and separation plates 40 In the case of a trained electric field, the ionized overspray particles separate on the ice sheet 62 on the separation plates 40 off and remain to a large extent on the ice sheet 62 be liable.

If necessary from the separation plates 40 dripping down overspray is from the conveyor belt 58 collected and to the collection area 60 promoted.

Most of the ionized overspray particles are already separated in the corona section 54 the electrode device 44 at the separation plates 40 from. That between the corona wires 56 and the respective deposition plate 40 the separation unit 36 However, existing electric field is inhomogeneous than the electric field in the region of the grid electrode 52 why there is a more judicious deposition of the ionized overspray particles on the corresponding deposition plate 40 he follows. As a result, the overspray particles, which the Korona section 54 have happened in the field section 50 effectively deposited.

The while passing through the separation unit 36 cabin air freed from overspray and thus cleaned enters the flow channel 124 on, the conditioning unit passes 126 in which it is conditioned accordingly, and passes over the flow channel 130 back in the paint tunnel 8th ,

For proper operation of the separation unit 36 Care must be taken that there is between the separation plates 40 and the electrode means 44 always be able to form a sufficiently strong electric field. However, this is only up to a certain layer thickness of deposited paint overspray on the separation surface 42 or the ice layer 62 possible because such a layer has an insulating effect. The strength of the insulation effect of the constructed overspray layer can be greater than the power requirement of the separation unit 36 , which generates the corresponding corona current, which decreases over time.

Due to the insulating effect of adhering to the release agent overspray, the corona current decreases with increasing thickness of the overspray layer. The corona current is usually determined empirically and is usually a few milliamperes per high voltage electrode.

In addition, solid particles and also binder components from the deposited overspray migrate from the surface of the ice sheets 62 into the ice. After a certain period of operation there is a risk that solid particles up to the separation surfaces 42 wander and settle there, what the functioning of the separation unit 36 severely impair and would require a costly cleaning and maintenance.

If the insulation effect of the deposited overspray is therefore too large and / or proper operation of the separation unit 36 can no longer be guaranteed, the ice sheets 62 with now adhering overspray from the separation plates 40 removed and the separation surfaces 42 the separation plates 40 with a fresh layer of ice 62 Mistake.

For this purpose, the valves 98 . 100 . 104 . 106 . 110 . 112 . 116 and 118 of the circulation system 78 adjusted so that the cooling medium in the second cycle 122 that flows in 6 is highlighted. In this case, the heat exchanger 88 and the evaporator 92 via the first bypass fluid line 96 bypassed by the cooling medium, whereby the separation plates 40 be flowed through by cooling medium, which previously in the compressor 82 was compressed and thereby heated and now heated over the manifold block 72 to the individual separation plates 40 arrives. In the present embodiment, it is assumed that the cooling medium is the compressor 82 leaves at a temperature of about 70 ° C and into the separation plates 40 flows.

This warms the separation plates 40 to a temperature at which the ice layer 62 on the respective separation surfaces 42 melts. The ice layers 62 with adhering overspray then slip due to gravity of the separation plates 40 down and fall down along with water as water / ice / overspray mixture on the conveyor 58 , This then transports the material mixture to the collection area 60 from where it is fed to a treatment. For this purpose, the material mixture, for example, can be further heated, whereby any ice still present is completely liquefied. The resulting water / overspray mixture can hereinafter z. B. be separated by suitable filters. The filtered overspray can optionally be fed to a further treatment or its disposal, as it is known per se.

After the coolant the separation plates 40 has flowed through, it is slightly cooled compared to its inlet temperature. Starting from the above assumed starting temperature of 70 ° C and finally reaches the cooling medium at a temperature of about 50 ° C to collecting block 76 , From there, the cooling medium flows to the evaporator 92 where it is cooled even further, for example to about 30 ° C. The cooling medium, which is the evaporator 92 leaves, still has a temperature sufficient to use the cooling medium for the conditioning of the cabin air and this through the heat exchanger coil 86 of the heat exchanger 88 to lead. From there, the cooling medium finally flows again cooled by about 10 ° C, so in the present example with a temperature of about 20 ° C, back to the compressor 82 back, where it is compressed again and thus heated.

After all the deposition plates 40 the separation unit 36 are freed of ice with adhering overspray, the valves are 98 . 100 . 104 . 106 . 110 . 112 . 116 and 118 of the circulation system 78 again adjusted so that the cooling medium in the first cycle 120 that flows in 5 is clarified, and water from the in the separation room 28 prevailing atmosphere at the separation areas 42 condensed out and there to the ice layer 62 freezes.

As an alternative or in addition to the second cycle 122 can the separation plates 40 in a modification also with external heating units, such as IR lamps, are heated.

The working periods, over which a separating plate 40 on a fresh layer of ice 62 has been produced, can be used and after which an existing ice sheet 62 removed with solids deposited on it and a fresh layer of ice 62 on the separation plate 40 is dependent, inter alia, on the behavior of the overspray.

In the separator described above 38 become all separation plates 40 cooled or heated at the same time, so that the overspray of all the deposition plates 40 is removed in a single process step and on all deposition plates 40 at the same time a new layer of ice 62 is trained.

In a modification, also several circulation systems 78 be provided, each having a group of deposition plates 40 or even just a single separator plate 40 feed with cooling medium. In this case, different areas of the separation unit 36 individually freed of ice / overspray and again with a fresh layer of ice 62 be provided. If in this case the deposition process should not be interrupted, this must be the relevant deposition plate 40 or the relevant group of separation plates 40 from the separation room 28 be removed, otherwise overspray at the exposed Abscheideflächen 42 could separate if the ice layer 62 was just removed.

The entire refrigeration cycle includes means to remove excess heat, as is well known in the art.

In the 8th and 9 is one of the 2 corresponding representation of a modified separator shown, the reference numeral 138 wearing. All components, those of the separator 36 correspond, bear the same reference numerals.

In this separation device 138 includes each separation plate 40 an external matrix of Peltier elements 140 , as known from the prior art and of which in the 8th and 9 only a few are provided with a reference numeral. For the sake of clarity, the interconnection of the Peltier elements 140 not shown, nor the ice sheet 62 , The Peltier elements 140 have an externally accessible layer 142 and an inner layer 144 , each one wall 40.1 or 40.2 the separation plate 40 facing, which is the corresponding Peltier element 140 wearing.

In 9 are the walls 40.1 and 40.2 every separation plate 40 to recognize, between which the cooling line 64 runs. The outer surfaces of the Peltier elements 140 Total make up the separation area 42 the associated separation plate 40 ,

The separation plates, which at the opposite ends of the separator 36 are arranged, carry in 9 the reference numerals 40a respectively. 40b , These separation plates 40a . 40b are only on their to an electrode device 44 facing outer surface of the wall 40.2 respectively. 40.1 with Peltier elements 140 stocked. The between the terminal separation plates 40a . 40b arranged separation plates 40 of which in 9 only one is shown, each carrying both on the outer surface of the wall 40.1 as well as on the outside surface of the wall 40.2 Peltier elements 140 ,

The three points between the separation plate 40b and the in 9 right electrode device 44 indicate that there are more separation plates in between 40 and electrode devices 44 are located.

In the embodiment shown here with Peltier elements 140 is the circulation system 78 still available, with the respective cooling line 64 the separation plates 40 connected is. Thus, here forms the circulation system 78 in connection with the cooling pipes 64 the separation plates 40 and the Peltier elements 140 the device, by means of which in each case a fresh layer of ice 62 on the separation surfaces 42 generated and / or one each on the Abscheideflächen 42 existing ice layer 62 can be removed with separated solids.

To create a layer of ice 62 on the Peltier elements 140 on the one hand, the valves 98 . 100 . 104 . 106 . 110 . 112 . 116 and 118 of the circulation system 78 adjusted so that the cooling medium in the first cycle 120 that flows in 5 is clarified and as explained above. In addition, however, are now the Peltier elements 140 according to their arrangement on the separation plates 40 so energized that their outer layers 142 cooling down.

This heats up the respective inner layer 144 the Peltier elements 140 that the walls 40.1 or 40.2 the separation plates 40 is adjacent. The walls 40.1 and 40.2 absorb this heat, which in turn on the through the cooling line 64 transmitting cooling medium is transferred and discharged from this.

In due course, the ice sheets 62 with adhering overspray from the separation plates 40 to remove, is the circulation system 78 operated as explained above in this context. The Peltier elements 140 However, they are disabled, so they heat up. Alternatively, the Peltier elements 140 by reversing the current direction can also be reversed, so that their outer layers 142 heat up and melt the ice. The respective inner layers 144 the Peltier elements 140 that the walls 40.1 or 40.2 the separation plates 40 are adjacent, cool down accordingly, which also causes the temperature of the respective walls 40.1 and 40.2 the deposition plates 40 reduced. These, in turn, absorb heat from the heated cooling medium passing through the separation plates 40 flows.

If the separator 138 can be used in a further modification to the circulation system 78 be waived and the required temperature of the separation surfaces 42 solely by means of the Peltier elements 140 be generated. In this case, the Peltier elements 140 according to the desired effect, namely the cooling or heating of their externally accessible outer layer 142 , energized. In this case, the Peltier elements form 140 thus taken alone the device, by means of which in each case a fresh layer of ice 62 on the separation surfaces 42 generated and / or one each on the Abscheideflächen 42 existing ice layer 62 can be removed with separated solids.

In a further modification, the separation plates 40 be heated by means of a heater, such as by means of the Abscheidplatten 40 attached heating wires. These can optionally on the respective outer or inner surface of the respective deposition plate 40 be provided.

A heater may be in addition to the Peltier elements 140 to be available; in this case, the latter are preferably only for cooling the separation plates 40 energized. In addition, on the second cycle 122 of the circulation system 78 be waived, eliminating the entire line structure of the circulation system 78 is simplified.

By such. Heating device is also a separate heating of individual separation plates 40 readily possible.

Claims (23)

Method for separating overspray from the overspray-laden cabin exhaust air of coating installations, in particular painting installations, in which the overspray is taken up by an air stream and conveyed to an electrostatically operating separation apparatus (US Pat. 38 ), where a majority of at least the solids from the overspray on at least one separation surface ( 42 ) is deposited, on which a release agent is applied, characterized in that as a release agent on the at least one Abscheidefläche ( 42 ) a layer of ice ( 62 ) is produced. A method according to claim 1, characterized in that after a working period one on the at least one Abscheidefläche ( 42 ) existing ice layer ( 62 ) with separated solids and a fresh layer of ice ( 62 ) on the at least one separation surface ( 42 ) is produced. Method according to claim 1 or 2, characterized in that as at least one separation surface ( 42 ) a surface area of a deposition plate ( 40 ) is used. Method according to claim 3, characterized in that a separation plate ( 40 ), one or more Peltier elements ( 140 ). A method according to claim 3 or 4, characterized in that a cooling medium through the separation plate ( 40 ). A method according to claim 5, characterized in that for producing the ice layer ( 62 ) on the at least one separation surface ( 42 ) cooled cooling medium through the separation plate ( 40 ) is passed to the separation plate ( 40 ) to cool so that water from the separating plate ( 40 ) surrounding atmosphere as an ice layer ( 62 ) on the at least one separation surface ( 42 ). A method according to claim 5 or 6, characterized in that for removing an ice layer ( 62 ) with separated solids from the at least one separation surface ( 42 ) heated cooling medium through the separation plate ( 40 ) is passed to the separation plate ( 40 ) such that ice on the at least one separation surface ( 42 ) at least on the separation surface ( 42 ) facing side of the ice sheet melts. Method according to one of claims 5 to 7, characterized in that the cooling medium during the production of the ice layer ( 62 ) in a cycle ( 120 ) with a compressor device ( 82 ) and an evaporator device ( 92 ). A method according to claim 8, characterized in that the cooling medium between the compressor device ( 82 ) and the evaporator device ( 92 ) through the heat exchanger coil ( 86 ) of a heat exchanger ( 88 ) to be led. A method according to claim 9, characterized in that the freed of solids cabin air through the heat exchanger ( 88 ). Method according to one of claims 8 to 10, characterized in that the cooling medium for heating the at least one Abscheidfläche ( 42 ) from the compressor device ( 82 ) coming to the evaporator device ( 92 ) over to the separation plate ( 40 ). A method according to claim 11, characterized in that the cooling medium also on the heat exchanger ( 88 ) is passed. Device for separating overspray from the overspray-laden car exhaust air of painting installations with a) at least one separation surface ( 42 ), on which the cabin exhaust air can be guided along and which is connected to one pole of a high-voltage source ( 46 ) connected is; b) an electrode device arranged in the airflow ( 44 ), which of the separation surface ( 42 ) and connected to the other pole of the high voltage source ( 46 ), characterized in that c) an ice layer ( 62 ) as release agent on the at least one separation surface ( 42 ) is generated. Device according to claim 13, characterized in that it comprises a device ( 64 . 78 . 140 ; 64 . 78 ' . 140 ) by means of which a fresh layer of ice ( 62 ) on the at least one separation surface ( 42 ) and / or one on the at least one separation surface ( 42 ) existing ice layer ( 62 ) is removable with separated solids. Apparatus according to claim 13 or 14, characterized in that the at least one separation surface ( 42 ) a surface area of a deposition plate ( 40 ). Apparatus according to claim 15, characterized in that the separation plate ( 40 ) one or more Peltier elements ( 140 ). Apparatus according to claim 15 or 16, characterized in that in the interior of the deposition plate ( 40 ) a cooling line ( 64 ), through which a cooling medium can be conducted. Apparatus according to claim 17, characterized in that the cooling medium at least temporarily in a cycle ( 120 ) with a compressor device ( 82 ) and an evaporator device ( 92 ), which is connected to the cooling line ( 64 ) connected is. Apparatus according to claim 18, characterized in that between the compressor device ( 82 ) and the evaporator device ( 92 ) a heat exchanger ( 88 ) with a heat exchanger coil ( 86 ) is arranged, through which of the compressor device ( 82 ) coming coolant is conductive. Device according to claim 19, characterized in that a flow path ( 132 ) of the freed of particulate cabin air through the heat exchanger ( 88 ) leads. Device according to one of claims 18 to 20, characterized in that a via valves ( 98 . 100 ) switchable bypass line ( 96 ) is present, via which the cooling medium at least temporarily from the compressor device ( 82 ) coming to the evaporator device ( 92 ) over to the cooling line ( 64 ) of the separation plate ( 40 ) is conductive. Apparatus according to claim 21, characterized in that the bypass line ( 96 ) runs such that the cooling medium also at the heat exchanger ( 88 ) over to the cooling line ( 64 ) of the separation plate ( 40 ) is conductive. Plant for coating, in particular for painting objects, in particular vehicle bodies ( 4 ), with a) a coating booth ( 2 ), in which the objects ( 4 ) can be acted upon with coating material and through which an air flow can be passed, which receives and dissipates the resulting overspray particles of the coating material; b) an electrostatically operating separation device ( 38 ), characterized in that c) the electrostatic precipitator device ( 38 ) is designed according to one of claims 13 to 22.

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