EP1108475B1 - Painting installation - Google Patents

Abstract

The device has a paint container (12) and a sprayer (18) that can be brought to an electrical potential relative to the object and electrostatically isolated from the paint feed by an electrostatic isolating device with an insulating line (22) also forming the pint feed to the container and a pad (24) movable reciprocally in the line that removes electrically conducting coating material from the inner surface of the line as it passes through it. Independent claims are also included for the following: the use of a scraper movable through a guide section to electrostatically isolate two system parts.

Description

The invention relates to a painting device with a Paint container and a spray device, the Paint container and the spray device for Applying paint to an object to be painted, in particular a motor vehicle body, compared to the Object can be brought to electrical potential and by means of an electrostatic separator against one Paint supply side is electrostatically isolable.

Such electrostatic painting devices are e.g. from US 4 921 169 known. To almost the entire amount of paint on the to be able to apply the painting object Spray device and one arranged in front Paint container on the painting device High voltage in the order of more than 50 kV compared to the paint to be kept at earth potential Brought object. Because of the resulting electric field, almost the entire amount of paint is applied applied the object to be painted and the Paint loss minimized accordingly. To do this, use a mechanically acting electrostatic Separating device for the intermediate container and the spray or Atomizing device after filling the Intermediate container mechanically separated and then on the object to be painted Brought high tension. Construction, training and operation such a mechanical separation device complex and expensive, since liquid-carrying lines for Filling the paint receptacle liquid-tight connected and separated from each other have to. That in the connecting sections of the lines remaining coating material also brings Problems with themselves.

The present invention is based on the object electrostatic decoupling or connection of the Feed side of the painting device with the high voltage bringable components, which the paint container and comprise the spray device, simpler, more user-friendly and less susceptible to faults and thus to make it more cost-effective to operate.

This task is carried out at a painting facility mentioned type according to the invention solved in that the electrostatic separation device an electrical insulating on the feed side of the paint container provided line section, which also the paint supply serves in the paint receptacle, and one inside the Line section includes reciprocating pig, which when moving through the pipe section thereof inner surface of electrically conductive liquid freed.

Under a newt one is led by a conduction agent in the understood in the broadest sense a body that moves especially for painting equipment for expressing Coating materials from pipes and for cleaning the lines during or after a rinsing process Solvent is used. Usable for this Pig bodies are known per se; at least they are like that Resiliently trained to be minimal Excessively insertable in a pipe means and in substantially resilient elastic against the inside of the Line means are applied and still movable are. If flexible ducting means for example made of plastic materials Hoses are used, so can also in essential unyielding pig bodies are used. The use of pig bodies in painting facilities however, was only used for cleaning purposes. With the Invention has now been recognized through use a pig in conjunction with one from an electrical insulating material formed a line section electrostatic separator can be formed at which can only be done by moving the pig through the Line section an electrostatic insulation at a High voltage painting device can be achieved without that mechanical separation of components of the Painting equipment is required. By moving through of the pig through the line section becomes its interior Surface as if by a lip or squeegee from any electrically conductive liquid (Coating material, detergent) and it can high-voltage insulation can thereby be achieved.

According to the invention, it is not electrically or in the essential non-conductive voltage insulation over the Length of pigged line section reached. this includes it is understood that when a voltage of 100 kV over a length of the line section of approx. 300 mm Current flow less than 50 µA, preferably less than 30 µA.

It is also pointed out that in the sense of present invention the frequently used term "lacquer" to be understood in the broadest sense as a coating material is; it can be water-based paints, hydraulic fillers, Powder slurry, water clear lacquer or watery Preservatives or other electrically conductive Trade coating materials.

With a view to extensive electrostatic separation or electrical insulation between the components of the Painting device has proven to be advantageous if the line section is at least 100 mm, preferably of at least 200 mm.

When the painting device is in operation, the Paint receptacle and the spray or Atomizing device compared to that to be painted Object to an electrical potential above 50 kV, preferably above 70 kV, in particular up to 100 brought kV.

It has also proven to be useful if the Line section runs obliquely to the horizontal, but is preferably arranged substantially vertically.

This has the advantage that the electrostatic separation related line section to Measure a certain amount of liquid (Rinsing liquid or coating material) can be achieved by displacing an air volume accumulates at the top and can be easily vented there.

The line section is preferably made of one high-voltage resistant plastic tubing or from a break-proof high-strength glass tube educated.

It would be the corresponding dimensional accuracy of each other components of the line section and the Newt conceivable that the newt itself any has a cylindrical or spherical shape. It has, however, become very complete Cleaning the inner surface of the pipe section proven to be advantageous if the newt has at least one serving as a sealant or trigger and against the inner Surface of the line section under tension or pressure has a bead or lip.

Furthermore, it proves to be advantageous that on the one or the other side of the line section Detergent supply or discharge connection is provided. On in this way, the line section which a Insulating section forms and which may subsequent receiving sections for the newt and the The pig itself is cleaned of coating material, in particular, the detergent can be a solvent for the Include coating material.

At least in principle it would be conceivable that the pig through any but electrically insulating push or Traction means is moved through the line section, in particular, a mechanically acting traction means in Form of a nylon thread or the like can be used. It would also be conceivable to use a vacuum generating means Use the pig to move back and forth. As in contrast advantageous, easy to use and light But it turns out to be manageable if a fluid Displacement medium, preferably compressed air, is used and on one and / or other side of the Line section a feed connection for the Displacement medium is provided, which is used as a pushing agent for the newt.

In a further development of the invention, the painting device a rinsing device assigned to the spray device include, in a corresponding manner against a Detergent supply side or a detergent supply connection is electrically insulated. Such a flushing device proves to be advantageous to the spray device, for example, a bell-type sprayer, at a color change or at the end of painting operations to be able to rinse with solvent.

Also a return side of this sprayer assigned flushing device can on the corresponding way according to the invention a piggable Include line section as an insulating section.

It is also detached from the one described above Painting system protection claimed for the new use of a through a line section moving pig for electrostatic separation of two parts of the system by moving the pig through the Line section moved through and the inner Surface of the line section of electrically conductive Liquid is freed.

Figur 1

eine schematische Ansicht einer erfindungsgemäßen Lackiereinrichtung; und

Figur 2

eine Schnittansicht eines Molchs.

Further features, details and advantages of the invention result from the patent claims as well as the graphic representation and the following description of preferred embodiments of the invention. The drawing shows:

Figure 1

a schematic view of a painting device according to the invention; and

Figure 2

a sectional view of a newt.

Figure 1 shows a schematic representation of a Paint shop. A color changer 2 is not with one ring system shown, which a variety of includes paint-carrying lines, connected. In connection to the color changer 2 is a color pressure regulator 4 and one Quantity metering device 6 is provided. To the Quantity metering device 6 is included overall designated by the reference numeral 8 and closer to descriptive electrostatic separator 8, which a paint supply side 10 and one Paint receptacle 12 connects or in the paint shop electrostatically separates from each other. Of the Paint receptacle 12 serves as an intermediate reservoir for Coating material, which has a line leading away from the bottom of the paint receptacle 12 14 with a further metering device 16 of a spray or atomization device 18 of the painting system becomes. In the case shown, it is a Bell-type sprayer 18.

To start up the painting facility, use the Color changer 2 a ring line with a specific Coating material, such as a certain color, connected in terms of flow to the paint receptacle 12, and via the color pressure regulator 4 and the Quantity metering device 6 is coating material in the Paint receptacle 12 introduced. After filling the Paint receiving container 12 is on the separator 8th the paint container 12 and the itself subsequent components 14 and 16 and the Spray device 18 from the feed side 10 to even closer to be described electrostatically separated and in a Brought potential of 100 kV. Then in itself known manner within the paint receptacle 12th generates a compressed air cushion 20 under the admission of compressed air and the coating material via line 14 and the Quantity metering device 16 by the spray device 18 atomized and onto the object to be coated applied. For refilling the paint container 12, the high voltage is turned off first, and then an electrical connection is made through the Separating device 8 with the feed side 10 again produced.

The electrostatic separation device 8 comprises one Line section 22 with a length of at least 300 mm. With this length of the air insulation distance is in the occurring voltages (100 kV) with certainty Insulation achieved. This Line section 22 is of a high voltage resistant Piece of hose or from a break-proof, pressure-resistant Glass tube formed. Within the line section 22 is a pig or pig body 24 in the direction of the double arrow 26, that is, in the longitudinal direction of the line section 22 movably housed. To move the Pigs are at both ends of the line section 22 Supply connection 26 and 28 provided for compressed air, which in 1 are shown schematically. Furthermore are Detergent supply and discharge connections 30, 32 are provided. By applying compressed air via the compressed air connections 26, 28 can the pig 24 in one direction or the other from a respective end position to the other end position be moved. When moving the pig 24 through the Line section 22 becomes the inner surface of the Line section 22 quasi doctored or stripped, see above that the surface is completely conductive Coating material is cleaned. The line section 22 is shown by the double arrow 26 Insulating section electrically insulating, and that without mechanical separation of line-forming components would have to be made. After a first operating mode is the pig 24 in the upper indicated in Figure 1 End position. About the color pressure regulator 4 and Quantity metering device 6 becomes a programmed amount of paint through the line section 22 into the Paint container 12 promoted. The end of this The filling process is carried out by the pig 24 by this with the help of regulated compressed air over the Compressed air connection 26 from its first upper end position to its second lower end position, that with the Reference numeral 34 is designated, is moved and here the amount of paint in the line section 22 also displaced into the paint receptacle 12. there the inside of the line section 22 of paint cleaned, and it becomes a High voltage insulation achieved. Now the Paint receptacle 12 and the downstream Components are brought to high voltage and the Painting process by expressing the in the Paint receiving container 12 existing coating material be performed.

After the painting process, the high voltage is restored switched off, and it can be rinsed separately if necessary the line section 22 via the detergent connections 30, 32 done. Then the pig 24 is again used regulated compressed air via port 28 into its first upper end position moved. So the system is back ready for the next filling process.

According to a second operating mode, the pig 24 is switched on before the start the filling process from its first upper end position in moved its second lower end position 34, and the The paint container is then specified with a Paint quantity filled. Then the pig 24 is by means of regulated compressed air back to the first upper end position emotional. The line section 22 existing amount of paint losslessly into the paint supply side 10 pushed back. This also makes the inside of the Line section 22 cleaned and a High-voltage insulation using the double arrow 26 designated route reached. The following Painting process can begin.

In the lower part of Figure 1 is on both sides of the line 14 one shown overall with reference numeral 36 Flushing device 36 shown for the spray device 18. Via a connection 38 and a pressure regulator 40 Detergent in the feed-side part 36a of the Introduced flushing device 36 and from there to flush the Spray device 18 forwarded and finally over the return-side part 36b of the flushing device 36 and one Port 42 discharged from the system. Both in feed-side part 36a as well as in the return-side part 36b of the flushing device 36 is one according to the invention Insulated section 44 formed. There is also one Line section 46 through which the detergent is passed, provided and within the Line section 46 is a pig 48 back and forth moveable, whereby in the manner described above Cleaning the inner surface of the pipe section 46 and thus high-voltage insulation over section 44 is achieved.

It also proves advantageous that the Line section 46 a reproducible metering device for the amount of detergent. For a rinsing process depending on the type of paint and paint system 20 to 30 cc detergent. One measures over the cross section and the length of the line section 46 that needed Volume (including an additional volume for the compressed air), so you can use the over the pressure regulator 40 adjustable detergent pressure for a corresponding amount of detergent required allow to flow into the line section 46. The higher the Pressure the more the air volume is compressed and the greater the amount of detergent added. The Air volume contained therein will then be at the top of the line section 46 and can accumulate via a Vent connection 50 are drained. About one Compressed air connection 52 can then be in the line section Existing amount of detergent in the spray device 18 fed and finally via the return-side part 36b can be returned.

It should be noted that the position of the Connections to both the separator 8 and of the flushing device 36 is only indicated schematically are. The devices are designed such that the respective pig 24, 48 none of the connections shown blocked.

Figure 2 shows a sectional view of a pig 50 with a Pig basic body 52 and integrally formed thereon, the end faces forming elastomer body parts 54. Die Elastomer body parts 54 include obliquely to the longitudinal direction 56 inclined concentrically rotating in the circumferential direction Sealing lips 58 which are not the inside of one scrape off the line section shown. If on the Thrust side by means of a displacement medium, for example Compressed air, an overpressure is generated, this will the respective sealing lip 58 under tension against the Pressed inside of the pipe section. This will a particularly good cleaning of the inside of the Line section reached.

It is also pointed out that a piggable Line section in painting systems with several, especially receptacles connected in series can be arranged between these.

Claims (11)

1. Painting apparatus with a paint container (12) and a spraying device (18), whereby for applying paint to an object to be painted, in particular a motor vehicle body, the paint container (12) and the spraying device (18) may be brought to an electrical potential relative to the object and, by means of an electrostatic separating device (8), may be electrostatically isolated relative to a paint feed side (10), characterised in that the electrostatic separating device (8) comprises an electrically insulating conduit section (22) provided on the feed side (10) of the paint container (12), which also serves to feed the paint into the paint container (12), and a pipeline scraper (24) movable back and forth inside the conduit section which, when moving through the conduit section (22), frees its inner surface from electrically conducting fluid.
2. Painting apparatus according to Claim 1, characterised in that the conduit section (22) has a length of at least 100 mm.
3. Painting apparatus according to Claim 1 or 2, characterised in that the conduit section (22) is manufactured from a high voltage-resistant plastics hose material or comprises a shatterproof high strength glass tube.
4. Painting apparatus according to Claim 1, 2 or 3, characterised in that the electrical potential lies above 50 kV and preferably above 70 kV and in particular between 70 kV and 100 kV.
5. Painting apparatus according to one of the previous claims, characterised in that the conduit section (22) is arranged at an angle to the horizontal, preferably substantially vertically.
6. Painting apparatus according to one of the previous claims, characterised in that the scraper (24) has at least one bead or lip (58) serving as a sealing or removing means and applicable under tension against the inner surface of the conduit section.
7. Painting apparatus according to one of the previous claims, characterised in that on the one side and on the other side of the conduit section (22), rinsing medium inlet and outlet connections (30, 32) are provided.
8. Painting apparatus according to one of the previous claims, characterised in that on one and/or the other side of the conduit section (22) an inlet connection (26, 28) is provided for a displacing medium for moving the scraper (24) through the conduit section (22).
9. Painting apparatus according to one of the previous claims, characterised in that the displacing medium is gaseous.
10. Painting apparatus according to one of the previous claims, characterised in that, assigned to the spraying device (18), it has a rinsing device (36) which has an additional electrostatic separating device with an electrically insulating conduit section (46) between a rinsing fluid inlet connection (38) and the spraying device (18) and a scraper (48) movable back and forth in the interior of the conduit section (46), whereby said scraper, on moving through the conduit section (46), frees its inside surface from electrically conducting fluid.
11. Use of a scraper movable through a conduit section for electrostatic separation of two system sections of, for instance, a painting system, in that the scraper is moved through the conduit section and thereby the inner surface of the conduit section is freed from electrically conducting fluid.

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