DE102011109911A1 - Device for separating overspray - Google Patents

Abstract

An electrostatically operating device for separating overspray from the overspray-laden cabin exhaust air from paint shops comprises a plurality of electrically conductive separating elements (34a, 34b, 64) which are connected to a high-voltage source (32) and along which the cabin air can be guided. Overspray particles can be ionised by means of an ionization device (26) arranged in the air stream. At least the separation elements (34a, 34b, 64) are designed as replaceable disposable components.

Description

• a) mehreren elektrisch leitfähigen Abscheideelementen, die mit einer Hochspannungsquelle verbunden sind und an welchen entlang die Kabinenluft führbar ist;
• b) einer im Luftstrom angeordneten Ionisierungseinrichtung, mittels welcher Overspraypartikel ionisierbar sind.

The invention relates to an electrostatically operating device for separating overspray from the overspray-laden cabin exhaust air from paint shops

• a) a plurality of electrically conductive separation elements, which are connected to a high voltage source and along which the cabin air can be guided;
• b) an ionization device arranged in the air stream, by means of which overspray particles are ionizable.

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 the case of devices known from the market of the type mentioned in the introduction, the paint overspray is guided past separation elements and deposited there by ionizing the overspray particles by means of an ionization device and migrating to the separation elements on the basis of an electric field built up between the separation elements. The paint overspray particles adhering to the separation elements can then be mechanically stripped off and removed, for example.

The cleaning effect of such separators is indeed very high. For a continuous operation, however, it must always be ensured that a sufficiently strong electric field is formed, which is possible only up to a certain layer thickness of paint overspray on the precipitation elements, 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. In addition, it may happen that overspray reacts, hardens or dries at the separation elements, so that it can no longer be removed from the separation elements by simple stripping. In addition, the energy consumption in such separators is relatively high.

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

• c) zumindest die Abscheideelemente als austauschbare Einweg-Bauelemente ausgebildet sind.

This object is achieved in a separation device of the type mentioned in that

• c) at least the separation elements are designed as replaceable disposable components.

The invention is based on the recognition that disposable Abscheideelemente are contrary to popular belief inexpensive and also environmentally friendly. The treatment and / or disposal of such disposable separation elements is energetically and also in terms of the required resources more compatible than the effort in a deposition device in which the deposited paint is removed in a continuous process of existing separation elements.

With regard to handling, it is even particularly advantageous if the separation elements are covered by a separation module with a support structure carrying the separation elements, which is exchangeable as a structural unit. Thus, such a separation module can be quickly replaced as a whole and then at least partially fed to a treatment or disposal.

Consequently, it is advantageous if one component, several components or all components of the deposition module are designed as disposable components. This may be only the separation elements or the separation elements and other components of the separation module.

It is particularly environmentally friendly if one component, several components or all components of the separation module, but at least the separation elements, are made of a wet-strength recycled material.

It is favorable if one or more of the following materials is selected as wet-strength recycling material: paper and cardboard materials, corrugated cardboard, cartons with standing wave, honeycomb cartons or wrapping cartons, MDF material, wood or plastics, in particular polyethylene or polypropylene.

Since work is carried out in an electrostatically operating separation device with high voltages and it can lead to voltage flashovers between the electrodes involved, it is advantageous if at least the separation elements are made of a flame-retardant material.

Advantageously, a single separation element is designed as a deposition plate. A separation plate provides a large separation area.

Alternatively, a single separating element may be formed as a separator tube, which can be flowed through in the longitudinal direction of cabin air.

In this case, it may be advantageous if a discharge electrode is arranged in the interior of each separator tube, which is connected to one pole of the high-voltage source, and the associated separator tube is connected to the other pole of the high-voltage source.

In general, it may be favorable if the ionization device is arranged spatially in the region of the precipitation elements.

Alternatively, an arrangement may be effective in which the ionization device is arranged in an ionization region through which the cabin air to be cleaned flows before it reaches the separation elements.

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

1 a perspective and partially broken view of an air duct in which an electrostatic-working device for separating overspray according to a first embodiment is arranged;

2 a partially translucent view from above of the air duct with the separator of 1 ;

3 a perspective and partially broken view of an air duct in which an electrostatic-working device for separating overspray according to a second embodiment is arranged;

4 a perspective view of a separation module of the separator of 3 ;

5 an enlarged detail of the separation module of 4 ;

6 one of the 4 corresponding perspective view of a modified Abscheidemoduls the separator of 3 ,

First, it will open 1 Referenced. There is with 10 Altogether an electrostatically operating device for separating overspray from overspray-laden cabin air is referred to, which comes from a paint booth not specifically shown here.

The separation device 10 comprises a cross-sectionally rectangular air duct 12 which is from an upper wall 12a , a lower wall 12b and two opposite side walls 12c and 12d is limited. The one side wall 12c is shown partially broken away to give a glimpse of the canal 12 to grant.

Cab air laden with overspray flows according to the arrow 14 in the air duct 12 one is freed from overspray there and leaves the separation device 10 then according to the arrow 16 from where it flows back as purified air, optionally after further conditioning, in a cycle back into the paint booth.

The upper wall 12a of the air duct 12 has a passage opening 18 on, in which as a modular Abscheideeinheit a separation module 20 so in a separation area 22 of the air duct 12 mounted on it, that it can be flowed through by the cabin air laden with overspray.

In an ionization area 24 of the air duct 12 , the separation area 22 with the separation module 20 in the flow direction 14 upstream, there is an ionization device 26 . by which overspray particles are ionized before going to the separation module 20 reach.

The structure of the ionization device 26 is known per se and in particular comprises a large number of corona wires 28 that work as discharge electrodes. The corona electrodes 28 are transverse to the flow direction 14 the cabin air tensioned and a connection unit 30 with a high voltage source 32 connected. The latter is only in 1 and there also only very schematically illustrated.

The separation module 20 comprises a plurality of electrically conductive deposition elements, which in the present embodiment as electrically conductive deposition plates 34 are formed. The separation plates 34 are in a supporting structure 36 stored and so in the air duct 12 aligned so that they are parallel to the flow direction 14 run.

The separation plates 34 are each alternately over the high voltage source 32 with mass and connected to the positive pole, with mass-separating plates with 34a and positive pole deposition plates with 34b are designated. The two oppositely arranged on the outside separation plates 34a of the separation module 34 are at ground potential.

The on mass separation plates 34a have an upstanding connecting tab 38 on. The followers 38 protrude through first slots 42a in a cover plate 44 the supporting structure 36 therethrough.

In an analogous way, the positive pole deposition plates 34b one connecting tab each 40 on, which are accessible from outside, passing through second slots 42b in the cover plate 44 the supporting structure 36 protrude.

All followers 38 the mass separating plates 34a are over a first contact strip 46 and all followers 40 the positive pole separator plates 34b are over a second contact strip 48 connected to each other, which in turn each with the high voltage source 32 are connected. The contact strips 46 and 48 are from above on the followers 38 respectively. 40 attached and each have several to the number and the geometry of the connecting tabs to be joined together 38 respectively. 40 adapted recording notches 46a respectively. 48a on, of which only a single one is provided with a reference numeral.

The supporting structure 36 also includes two support legs 50 and 52 which the separation plates 34 flank. The carrying cheeks 50 . 52 on the one hand hold the cover plate 44 and on the other hand have one at the level of the followers 38 . 40 the connection plates 34 resident fold 50a . 52a , by means of which the separation module 20 as a unit at the edge of the passage opening 18 of the air duct 12 can be hung.

As in 1 can be seen running between the two wings 50 . 52 two spacers 54 , These hold on the one hand the separation plates 34 between the girders 50 . 52 evenly spaced and stabilize on the other the separation module 20 as a whole. In a modification may be to these spacers 54 be waived.

The bottom area of the filter module 20 is through a liquid-tight collection trough 56 formed for paint, attached to the deposition plates 34 separates and flows down it.

The separation plates 34 of the separation module 20 are designed as replaceable disposable components. For this purpose, the separation plates 34 Made of a wet-strength recycled material, which is ideally flame retardant and should also be recyclable. Cellulosic materials such as optionally treated paper and board materials, corrugated cardboard, standing wave cartons, honeycomb cartons or wrapping cartons may be used for this purpose.

Such materials, which by a special treatment have the required for an electrostatic deposition of overspray electrical conductivity and / or are flame retardant, are known in and of themselves from the prior art and are used for example as packaging materials.

Generally speaking, one component, several components or all components of the separation module 20 made of such a wet-strength recycled material, with only the separation plates 34 the electrical conductivity of the material used must be guaranteed. For the entire support structure 36 or for some of their components, other materials such. As MDF materials, wood or plastics such as in particular polyethylene or polypropylene into consideration.

The separation device 10 works like this:
The cabin air laden with overspray coming from the spray booth mentioned above flows according to the arrows 14 and 16 through the air duct 12 and at first to the ionization region 24 , There, the air flows around the corona wires 28 to which it in a well-known way too Corona discharges come through which the overspray particles are effectively ionized in the passing exhaust fumes.

The ionized overspray particles then pass to the separation module 20 in the separation area 22 of the air duct 12 and are on the separation plates 34 led along where they due to the alternating arrangement of the mass-separating plates 34a and the positive pole deposition plates 34b in any case, a pair of a mass-separating plate 34a and a positive pole deposition plate 34b happen. Due to the between mass-separating plate 34a and positive pole separator plate 34b In the case of a trained electric field, the ionized overspray particles separate depending on their charge at the corresponding precipitation elements 34a or 34b as a varnish layer. There, the deposited paint flows down into the sump 56 ,

Each separation module 20 is designed to accommodate a maximum amount of paint, ie for a limit loading with overspray, the type of the separation module 20 and the materials used for this depends. The amount of paint already taken up can be determined, for example, in a manner known per se by means of a balance or by means of a differential pressure determination. The larger the loading of the filter module 20 is, the larger is the through the filter module 20 constructed air resistance.

If a filter module 20 now reaches its maximum absorption capacity, it is against an unloaded filter module 20 replaced. For this purpose, first the contact strips 46 and 48 from the followers 38 . 40 the separation plates 34a . 34b away. Then the separation module 20 as a unit from the passage opening 18 in the air duct 12 led to the outside and the exchange separation module 20 used, on the follower 38 . 40 the contact strips 46 and 48 then put back on.

The exchanged and overspray loaded separation module 20 is then fed to a disposal and / or recycling process and thus used as a disposable separation module.

In a modification, the separation module comprises 20 no collection tub 56 , In this case, the air duct points 12 in the bottom wall 12b a passage, can drip on the downflowing paint in a arranged below this passage collection reservoir. In this training, only the separation plates 34 be used as disposable components, whereas the remaining components remain stationary installed. For this purpose, for example, the cover plate 44 of the separation module 20 detachable with the support legs 50 . 52 be connected, of which they together with the wetted with paint deposition plates 34 can be removed.

A system not shown here for the separation of overspray usually includes several deposition devices 10 or at least several separation modules 20 ,

In the 3 to 5 is now a second embodiment of a separation device 60 shown, with components that have already been explained above, the same reference numerals.

In this separation device 60 overlap the separation area 22 and the ionization area 24 spatially in the air duct 12 , This is a modified separation module 62 provided, which the corona wires 28 includes, here in the flow direction 14 . 16 run. Instead of separating plates are as separating elements electrically conductive separator tubes 64 present as a tube matrix also parallel to the flow direction according to the arrows 14 . 16 are arranged and for this purpose at their opposite ends of a respective bearing plate 66 respectively. 68 are worn, which here the support structure 36 form. The separator tubes 64 can be flowed through in the longitudinal direction of the cabin air to be cleaned.

Inside every separator tube 64 a discharge electrode is arranged. This extends through each Abscheideröhre 64 each coaxial with a corona wire 28 through which at each end of the separator tube 64 in the middle of a cross structure 70 in particular, in 5 easy to recognize. In every open end of a separator tube 64 is such a cross structure 70 used.

The corona wires 28 are with a pole in the 3 to 5 not shown high voltage source 32 and the separator tubes 64 are with the other pole of the high voltage source 32 connected. Overspray particles passing through the corona wires 28 ionized, then divide due to the between each corona wire 28 and the associated Abscheideröhre 64 formed electric field on the inner wall of the Abscheideröhre 64 from. There, the paint runs to the bottom of the tube down together and then exits upon reaching a certain level of paint at the two open ends. From there, the paint can flow down to, for example, a collection trough which is not specifically shown.

The separation module 62 becomes when it reaches its limit load in the flow direction 14 . 16 from the air duct 12 pulled and through an unloaded separation module 62 replaced. The separation module 62 gets along with the corona wires 28 and the superimposed cross structures 70 recycled or disposed of.

In 6 is a modified separation module 62 shown.

To the overspray laden cabin air entering the separator tubes 64 To facilitate, are the corona wires 28 there only at one end of a single cross structure 70 carried. The cross structures 70 are each in the end of the associated Abscheideröhre 64 used, from the freed from overspray cabin air from the separation module 62 exit, as is the case with the partially broken separator tube 64 can be seen. The corona wires 28 are in this case rod-like and have a material thickness, so that they do not bend or only slightly in the longitudinal direction.

In this embodiment of the ionization device 26 this can optionally be operated with less energy than in the case of the corona wires clamped on both sides 28 , In this case, the free tip of the corona wires works 28 am from the cross structures 70 distal end as a spray tip, through which the overspray particles on entering the Abscheideröhren 64 be ionized. Between the corona wires 28 and the associated Abscheideröhren 64 Then only an electric field is built without the wire body of the corona wires 28 also works as a spray electrode.

Also with the separation module 62 are all or some components, but especially the Abscheideröhren 64 manufactured as disposable components of a wet-strength recycled material, as explained above.

For the supporting structure 36 ie here for the bearing plates 66 . 68 , come the above-mentioned other materials such. As MDF materials, wood or plastics such as in particular polyethylene or polypropylene into consideration.

In the separation module 62 can the separator tubes 64 also be twisted about its longitudinal axis. In this way it can be achieved that overspray as a more or less uniform film on the inner wall of the Abscheideröhren 64 reflected. Leakage of paint from the ends of the Abscheideröhren can be prevented or at least delayed.

For this purpose, the separator tubes 64 correspondingly rotatable in the bearing plates 66 . 68 be stored and coupled with a drive mechanism. When the separator tubes 64 a kind of external toothing, z. B. in the form of a longitudinal corrugation, and are arranged so close together that the outer teeth of adjacent Abscheideröhren 64 meshing, it may be sufficient if only a few or only a few of the Abscheiderähren is driven.

Claims (11)

Electrostatically operating device for separating overspray from the overspray-laden cabin exhaust air from paint shops with a) a plurality of electrically conductive separation elements ( 34a . 34b ; 64 ) connected to a high voltage source ( 32 ) and along which the cabin air can be guided; b) an ionization device arranged in the air flow ( 26 ), by means of which overspray particles are ionizable, characterized in that c) at least the precipitation elements ( 34a . 34b ; 64 ) are designed as exchangeable disposable components. Apparatus according to claim 1, characterized in that a plurality of separation elements ( 34a . 34b ; 64 ) from a separation module ( 20 ; 64 ) with one of the separation elements ( 34a . 34b ; 64 ) carrying support structure ( 36 ), which is interchangeable as a structural unit. Device according to claim 2, characterized in that one component, several components or all components of the separation module ( 20 ; 64 ) are designed as disposable components. Device according to claim 3, characterized in that one component, several components or all components of the separation module ( 20 ; 64 ), but at least the separation elements ( 34a . 34b ; 64 ), are made of a wet-strength recycled material. Apparatus according to claim 3 or 4, characterized in that as wet-strength recycled material one or more of the following materials is selected: paper and cardboard materials, corrugated cardboard, cartons with standing wave, cartons with honeycomb or wrapping cartons, MDF material, wood or plastics, in particular Polyethylene or polypropylene. Device according to one of claims 1 to 5, characterized in that at least the separation elements ( 34a . 34b ; 64 ) are made of a flame retardant material. Device according to one of claims 1 to 6, characterized in that a single Separation element ( 34a . 34b ; 64 ) as a deposition plate ( 34a . 34b ) is trained. Device according to one of claims 1 to 6, characterized in that a single separating element ( 34a . 34b ; 64 ) as a separator tube ( 64 ) is formed, which can be flowed through in the longitudinal direction of cabin air. Apparatus according to claim 8, characterized in that inside each Abscheideröhre ( 64 ) a spray electrode ( 28 ) arranged with one pole of the high voltage source ( 32 ), and the associated Abscheideröhre ( 64 ) with the other pole of the high voltage source ( 32 ) connected is. Device according to one of claims 1 to 9, characterized in that the ionization device ( 28 ) spatially in the region of the separation elements ( 64 ) is arranged. Device according to one of claims 1 to 8, characterized in that the ionization device ( 28 ) in an ionization region ( 24 ) is arranged, which depends on the cabin air to be cleaned before reaching the separation elements ( 34a . 34b ; 64 ) is flowed through.

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