EP0034278B1 - Method and apparatus for the electrostatic coating of articles by means of a fluid - Google Patents

Method and apparatus for the electrostatic coating of articles by means of a fluid Download PDF

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Publication number
EP0034278B1
EP0034278B1 EP81100609A EP81100609A EP0034278B1 EP 0034278 B1 EP0034278 B1 EP 0034278B1 EP 81100609 A EP81100609 A EP 81100609A EP 81100609 A EP81100609 A EP 81100609A EP 0034278 B1 EP0034278 B1 EP 0034278B1
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EP
European Patent Office
Prior art keywords
bell
fluid
spray
spray bell
paint
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
EP81100609A
Other languages
German (de)
French (fr)
Other versions
EP0034278A2 (en
EP0034278A3 (en
Inventor
Roland Andreas Dipl.-Ing. Meisner
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
BASF Farben und Fasern AG
Original Assignee
BASF Farben und Fasern AG
BASF Lacke und Farben AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Publication date
Application filed by BASF Farben und Fasern AG, BASF Lacke und Farben AG filed Critical BASF Farben und Fasern AG
Priority to AT81100609T priority Critical patent/ATE9203T1/en
Publication of EP0034278A2 publication Critical patent/EP0034278A2/en
Publication of EP0034278A3 publication Critical patent/EP0034278A3/en
Application granted granted Critical
Publication of EP0034278B1 publication Critical patent/EP0034278B1/en
Expired legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
    • B05B3/00—Spraying or sprinkling apparatus with moving outlet elements or moving deflecting elements
    • B05B3/02—Spraying or sprinkling apparatus with moving outlet elements or moving deflecting elements with rotating elements
    • B05B3/10—Spraying or sprinkling apparatus with moving outlet elements or moving deflecting elements with rotating elements discharging over substantially the whole periphery of the rotating member, i.e. the spraying being effected by centrifugal forces
    • B05B3/1064—Spraying or sprinkling apparatus with moving outlet elements or moving deflecting elements with rotating elements discharging over substantially the whole periphery of the rotating member, i.e. the spraying being effected by centrifugal forces the liquid or other fluent material to be sprayed being axially supplied to the rotating member through a hollow rotating shaft
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
    • B05B5/00—Electrostatic spraying apparatus; Spraying apparatus with means for charging the spray electrically; Apparatus for spraying liquids or other fluent materials by other electric means
    • B05B5/025—Discharge apparatus, e.g. electrostatic spray guns
    • B05B5/04—Discharge apparatus, e.g. electrostatic spray guns characterised by having rotary outlet or deflecting elements, i.e. spraying being also effected by centrifugal forces
    • B05B5/0403—Discharge apparatus, e.g. electrostatic spray guns characterised by having rotary outlet or deflecting elements, i.e. spraying being also effected by centrifugal forces characterised by the rotating member
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
    • B05B5/00—Electrostatic spraying apparatus; Spraying apparatus with means for charging the spray electrically; Apparatus for spraying liquids or other fluent materials by other electric means
    • B05B5/025—Discharge apparatus, e.g. electrostatic spray guns
    • B05B5/04—Discharge apparatus, e.g. electrostatic spray guns characterised by having rotary outlet or deflecting elements, i.e. spraying being also effected by centrifugal forces
    • B05B5/0415—Driving means; Parts thereof, e.g. turbine, shaft, bearings

Definitions

  • the invention relates to a method for the electrostatic coating of objects with liquids, in particular liquid paint, by supplying the liquid to a high-voltage spray bell rotating at a high speed of between 15,000 and 60,000 rpm and throwing the liquid off the spray edge of the spray bell coating object with the help of an annular air jacket.
  • a so-called low-speed bell is known from DE-B-22 48 167, in which the paint is atomized by electrostatic forces. As soon as the paint is fed to the atomizer head, it is transported to the edge by centrifugal forces. The surface tension of the liquid causes the paint to form a bead on the outer edge of the spray head. Threads are drawn off electrically from this bead. Due to the shifting of the charge in the electric field, the force acting on the thread increases and the liquid pressure inside the thread also increases. If this pressure is greater than the surface tension, the thread is torn and has a high intrinsic charge due to the charge shift. All paint particles charged with the same polarity repel each other, but are attracted to the grounded workpiece.
  • centrifugal forces exclusively cause the paint to be transported to the atomizing edge. Only when the electric field is switched off and further paint supply is applied, is centrifugal forces throwing off paint from the bead growing on the edge of the bell. These drops have a large diameter and are not suitable for many painting jobs.
  • usable atomization is achieved only by the high voltage.
  • the electrical properties of the lacquer thus prove to be important for its good atomization. The higher the paint resistance, the higher the high voltage must be to facilitate good atomization.
  • a high-speed bell is known from DE-C-973 478, which forms the preambles of the independent claims. For every paint system there are speeds at which the centrifugal force becomes the decisive atomizing force, whereby electrostatic repulsion only plays a minor role.
  • High-speed bells can atomize both highly conductive and semi-conductive paints. All known constructions of this type, as they are also known, for example, as DE-B-12 40 764, work with an atomizer hub in order to prevent the paint from leaving the atomizer system before being transferred to the spray bell.
  • the invention has for its object to provide a method with which liquid, in particular liquid paint, can be sprayed onto an object to be processed, even difficult coating materials, such as metallic lacquers, can be processed and a uniform fine distribution of the liquid is ensured, without fear that there are air pockets and dried paint particles from the atomizer hub are re-introduced into the paint.
  • This object of the invention is achieved in that the liquid in the axial center of the circumferential spray bell in the axial direction of the same freely supplied to the bell interior and thereby slows down its conveying speed to almost zero and is exposed to the toroidal vortex formed there and by the toroidal vortex of the inner wall of the rotating bell is fed.
  • the invention makes use of the toroidal vortex which forms in a bell-shaped cavity at a high rotational speed of the bell and which has a circular bead rotating around its central axis with a backflow component directed deepest in the bell center and a bell executed on the inner edge of the bell to the outside of the bell and with the bell rotating flow component.
  • the paint to be sprayed is fed into the center of the bell in such a way that the paint mouth ends freely in the center of the bell space and is exposed here to the conveying component of the torus vortex directed backwards.
  • the momentum of the supplied liquid at the outlet opening of the liquid supply line is only so great that the forces applied by the toroidal vortex can cause a deflection in the direction of the inner surface of the bell.
  • the invention is also directed to a Device for electrostatically coating objects with liquids, in particular liquid paint, with a bell rotating about a fixed hollow axis with a central liquid supply and a number of compressed air nozzles surrounding the bell.
  • a device of this type is described in DE-C-973 478.
  • the outlet opening of the hollow axis opening centrally in the base of the bell opens freely towards the interior of the bell and a diffuser is provided in the region of the end of the hollow axis which reduces the conveying speed of the liquid conveyed in the hollow axis.
  • the known additional compressed air nozzles are arranged in the rear area of the spray bell, so that the air balance around the rotating bell is ensured and the sprayed paint mist cone receives a defined axial thrust from the circularly rotating air curtain.
  • a hollow axis 1 which supports bearings 10, 10 'for a spray bell 2 with a rotor 5, a stator 11 and a dynamic seal 20 and a fabric bushing 16.
  • An electrical lead 8 for the stator 11 is guided in a groove 17 on the hollow axis 1 through the bearing 10 '.
  • the hollow axis 1 ends in a diffuser 12, which is closed by a rectifying sieve 14.
  • the inlet of the diffuser 12 is designed as a valve seat 3, on which the liquid flow can be shut off using a valve needle 4.
  • the bell inner contour carries a radial toothing 15 for the transmission of the Coriolis force.
  • Compressed air nozzles 9 of a nozzle ring 6 produce an annular air curtain which imparts an axial thrust to the paint mist sprayed on a spray edge 13 of the spray bell 2.
  • the paint to be sprayed is introduced via a line 7.
  • a pneumatic drive with a turbine rotor 18 and a nozzle ring 19 is provided instead of the electric drive.

Landscapes

  • Application Of Or Painting With Fluid Materials (AREA)
  • Electrostatic Spraying Apparatus (AREA)
  • Paints Or Removers (AREA)
  • Pens And Brushes (AREA)

Abstract

Process for electrostatically coating objects with a fluid, for instance liquid paint, by applying a high voltage to a spray bell and by feeding the fluid to a revolving, driven spray bell. The flow-rate of the fluid supplied to the center of the spray bell is decelerated nearly to zero when it enters the bell, then the rate of the fluid is increased by being accelerated by the bell to 15,000 to 60,000 rpm, and the fluid thereupon is centrifuged off the spray rim of the bell and is guided to the object to be coated.

Description

Die Erfindung bezieht sich auf ein Verfahren zum elektrostatischen Überziehen von Gegenständen mit Flüssigkeiten, insbesondere flüssiger Farbe durch Zuführen der Flüssigkeit zu einer unter Hochspannung stehenden, mit hoher Drehzahl zwischen 15.000 und 60.000 UPM umlaufenden Sprühglocke und Abschleudern der Flüssigkeit von der Sprühkante der Sprühglocke auf den zu beschichtenden Gegenstand unter Zuhilfenahme eines ringförmigen Luftmantels.The invention relates to a method for the electrostatic coating of objects with liquids, in particular liquid paint, by supplying the liquid to a high-voltage spray bell rotating at a high speed of between 15,000 and 60,000 rpm and throwing the liquid off the spray edge of the spray bell coating object with the help of an annular air jacket.

Aus der DE-B-22 48 167 ist eine sogenannte Niedriggeschwindigkeitsglocke bekannt, bei welcher die Farbe durch Elektrostatikkräfte zerstäubt wird. Sobald der Lack dem Zerstäuberkopf zugeführt wird, wird er durch Fliehkräfte an den Rand transportiert. Die Oberflachenspannung der Flüssigkeit veranlaßt die Farbe zur Bildung eines Wulstes am äußeren Rand des Sprühkopfes. Aus diesem Wulst werden elektrisch Fäden abgezogen. Durch Ladungsverschiebung im elektrischen Feld wird die auf den Faden wirkende Kraft immer größer und damit steigt auch der Flüssigkeitsdruck innerhalb des Fadens. Wird dieser Druck größer als die Oberflächenspannung, wird der Faden zerrissen und hat infolge der Ladungsverschiebung eine hohe Eigenladung. Alle mit gleicher Polarität aufgeladenen Lackteilchen stoßen einander ab, werden jedoch vom geerdeten Werkstück angezogen. Die Zentrifugalkräfte bewirken auschließlich den Lacktransport zur Zerstäubungskante. Lediglich bei abgeschaltetem elektrischem Feld und weiterer Lackzufuhr wird Lack aus dem am Glockenrand anwachsenden Wulst durch Zentrifugalkräfte abgeschleudert. Diese Tropfen haben einen großen Durchmesser und sind für viele Lackierfälle nicht geeignet. Bei den relativ niedrigen Geschwindigkeiten der Sprühglocke zwischen 1000 und 4000 UPM wird eine brauchbare Zerstäubung ausschließlich durch die Hochspannung erzielt. Es erweisen sich somit die elektrischen Eigenschaften des Lackes als bedeutsam für seine gute Zerstäubung. Je höher der Lackwiderstand liegt, desto höher muß auch die Hochspannung sein, um eine gute Zerstäubung zu erleichtern.A so-called low-speed bell is known from DE-B-22 48 167, in which the paint is atomized by electrostatic forces. As soon as the paint is fed to the atomizer head, it is transported to the edge by centrifugal forces. The surface tension of the liquid causes the paint to form a bead on the outer edge of the spray head. Threads are drawn off electrically from this bead. Due to the shifting of the charge in the electric field, the force acting on the thread increases and the liquid pressure inside the thread also increases. If this pressure is greater than the surface tension, the thread is torn and has a high intrinsic charge due to the charge shift. All paint particles charged with the same polarity repel each other, but are attracted to the grounded workpiece. The centrifugal forces exclusively cause the paint to be transported to the atomizing edge. Only when the electric field is switched off and further paint supply is applied, is centrifugal forces throwing off paint from the bead growing on the edge of the bell. These drops have a large diameter and are not suitable for many painting jobs. At the relatively low speeds of the spray bell between 1000 and 4000 RPM, usable atomization is achieved only by the high voltage. The electrical properties of the lacquer thus prove to be important for its good atomization. The higher the paint resistance, the higher the high voltage must be to facilitate good atomization.

Aus der die Oberbegriffe der unabhängigen Ansprüche bildenden DE-C-973 478 ist eine Hochgeschwindigkeitsglocke bekannt. Für jedes Lacksystem gibt es Geschwindigkeiten, bei der die Zentrifugalkraft zur ausschlaggebenden Zerstäubungskraft wird, wobei elektrostatische Abstoßung nut noch eine geringe Rolle spielt. Hochgeschwindigkeitsglocken können sowohl gut leitende wie auch halbleitende Lacke zerstäuben. Alle bekannten Konstruktionen dieser Art, wie sie beispielsweise auch als der DE-B-12 40 764 bekannt sind, arbeiten mit einer Zerstäubernabe, um zu vermeiden, daß der Lack vor Übergabe an die Sprühglocke das Zerstäubersystem verläßt. Diese bekannten Verfahren haben jedoch den Nachteil, daß infolge der Sprühglockenkonstruktion selbst bei zentraler Lackzuführung das Farbgut vor dem Zerstäuben Unstetigkeitsstellen passieren muß, die beispielsweise durch den Bereich der Farbübergabe von der Farbzuführung zur Glocke und durch die die Glocke tragenden Stege od. dgl. gebildet werden und die Veränderungen im Farbgut nach sich ziehen, indem zwangsläufig in diesen Unstetigkeitsbereichen Luft mit in das Farbgut, z.B. den Lack, eingeschlagen wird. Durch die Notwendigkeit einer zentralen Zerstäubernabe, um das Farbgut der Sprühkante zuzuführen, unterliegt die Außenseite dieser Zerstäubernabe einer unkontrollierbaren Verschmutzung durch durch den sich bildenden Toruswirbel mitgeführte Lackpartikelchen, die sich an der Oberfläche der Lackpartikelchen, die sich an der Oberfläche der Zerstäubernabe anlegen und teilweise abtrocknen.A high-speed bell is known from DE-C-973 478, which forms the preambles of the independent claims. For every paint system there are speeds at which the centrifugal force becomes the decisive atomizing force, whereby electrostatic repulsion only plays a minor role. High-speed bells can atomize both highly conductive and semi-conductive paints. All known constructions of this type, as they are also known, for example, as DE-B-12 40 764, work with an atomizer hub in order to prevent the paint from leaving the atomizer system before being transferred to the spray bell. However, these known methods have the disadvantage that, due to the spray bell construction, even with central paint supply, the paint must pass through discontinuities before atomization, which are formed, for example, by the area of the ink transfer from the paint supply to the bell and by the webs carrying the bell or the like and cause the changes in the colored material by inevitably adding air to the colored material in these discontinuity areas, for example the paint that is hammered in. Due to the need for a central atomizer hub in order to supply the paint to the spray edge, the outside of this atomizer hub is subject to uncontrollable contamination by paint particles carried along by the toroidal vortex that forms, which adhere to the surface of the paint particles, which attach to the surface of the atomizer hub and partially dry .

Der Erfindung liegt die Aufgabe zugrunde, ein Verfahren zu schaffen, mit dem Flüssigkeit, insbesondere flüssige Farbe, auf einen zu bearbeitenden Gegenstand aufgesprüht werden kann, wobei auch schwierige Überzungsmaterialien, wie beispielsweise Metalliclacke, verarbeiten werden können und eine gleichmäßige Feinverteilung der Flüssigkeit gewährleistet ist, ohne daß befürchtet werden muß, daß Lufteinschlüsse vorhanden sind und abgetrocknete Lackpartikelchen von der Zerstäubernabe wieder in das Farbgut eingetragen werden.The invention has for its object to provide a method with which liquid, in particular liquid paint, can be sprayed onto an object to be processed, even difficult coating materials, such as metallic lacquers, can be processed and a uniform fine distribution of the liquid is ensured, without fear that there are air pockets and dried paint particles from the atomizer hub are re-introduced into the paint.

Diese der Erfindung zugrundeliegende Aufgabe wird dadurch gelöst, daß die Flüssigkeit im axialen Zentrum der umlaufenden Sprühglocke in axialer Richtung derselben frei dem Glockeninnenraum zugeführt und dabei ihre Fördergeschwindigkeit auf nahezu Null verzögert und dem sich dort ausbildenden Toruswirbel ausgesetzt wird und von dem Toruswirbel der inneren Wand der rotierenden Glocke zugeführt wird.This object of the invention is achieved in that the liquid in the axial center of the circumferential spray bell in the axial direction of the same freely supplied to the bell interior and thereby slows down its conveying speed to almost zero and is exposed to the toroidal vortex formed there and by the toroidal vortex of the inner wall of the rotating bell is fed.

Die Erfindung nutzt den sich in einem glockenförmigen Hohlraum bei hoher Umlaufgeschwindigkeit der Glocke bildenden Toruswirbel aus, der ein um seine zentrale Achse rotierender umlaufender Kreiswulst mit einer im Zentrum der Glocke zum Glockentiefsten gerichteten Rückstromkomponente und einer am Innenrand der Glocke zum Glockenäußeren hingerichteten und mit der Glocke rotierenden Strömungskomponente ist. Die Zuführung der zu versprühenden Farbe in das Zentrum der Glocke erfolgt derart, daß die Zuführmündung der Farbe frei im Zentrum des Glockenraumes endet und hier der zurückgerichteten Förderkomponente des Toruswirbels ausgesetzt ist. Der Impuls der zugeführten Flüssigkeit an der Austrittsöffnung der Flüssigkeitszuführungsleitung ist nur so groß, daß die durch den Toruswirbel aufgeprägten Kräfte eine Umlenkung in Richtung auf die Glockeninnenfläche bewirken können.The invention makes use of the toroidal vortex which forms in a bell-shaped cavity at a high rotational speed of the bell and which has a circular bead rotating around its central axis with a backflow component directed deepest in the bell center and a bell executed on the inner edge of the bell to the outside of the bell and with the bell rotating flow component. The paint to be sprayed is fed into the center of the bell in such a way that the paint mouth ends freely in the center of the bell space and is exposed here to the conveying component of the torus vortex directed backwards. The momentum of the supplied liquid at the outlet opening of the liquid supply line is only so great that the forces applied by the toroidal vortex can cause a deflection in the direction of the inner surface of the bell.

Die Erfindung richtet sich weiterhin auf eine Vorrichtung zum elektrostatischen Überziehen von Gegenständen mit Flüssigkeiten, insbesondere flüssiger Farbe mit einer um eine feststehende Hohlachse rotierenden Glocke mit zentraler Flüssigkeitszufuhr und einer Anzahl von die Glocke umgebenden Druckluftdüsen. Eine Einrichtung dieser Art ist in der DE-C-973 478 beschrieben.The invention is also directed to a Device for electrostatically coating objects with liquids, in particular liquid paint, with a bell rotating about a fixed hollow axis with a central liquid supply and a number of compressed air nozzles surrounding the bell. A device of this type is described in DE-C-973 478.

Gemäß der Erfindung wird vorgeschlagen, daß sich die zentrisch im Glocken-grund mündende Austrittsöffnung der Hohlachse frei zum Glockeninnenraum hin öffnet und im Bereich des Hohlachsenendes ein Diffusor vorgesehen ist, der die Fördergeschwindigkeit der in der Hohlachse geförderten Flüssigkeit verringert.According to the invention, it is proposed that the outlet opening of the hollow axis opening centrally in the base of the bell opens freely towards the interior of the bell and a diffuser is provided in the region of the end of the hollow axis which reduces the conveying speed of the liquid conveyed in the hollow axis.

Vorteilhafte Ausgestaltungen der erfindungsgemäßen Vorrichtung sind in den Unteransprüchen erläutert. Hier wird beispielsweise vorgeschlagen, daß die an sich bekannten zusätzlichen Druckluftdüsen im rückwärtigen Bereich der Sprühglocke angeordnet sind, so daß einmal der Lufthaushalt um die rotierende Glocke sichergestellt wird und zum andern der abgesprüchte Lacknebelkegel durch den kreisringförmig rotierenden Luftschleier einen definierten Axialschub erhält.Advantageous embodiments of the device according to the invention are explained in the subclaims. Here, for example, it is proposed that the known additional compressed air nozzles are arranged in the rear area of the spray bell, so that the air balance around the rotating bell is ensured and the sprayed paint mist cone receives a defined axial thrust from the circularly rotating air curtain.

Ausführungsbeispiele der Erfindung werden nachfolgend anhand der Zeichnungen erläutert. Die Zeichnungen zeigen dabei in

  • Fig. 1 einen Schnitt durch eine Ausführungsform mit elektrischem Antrieb und in
  • Fig. 2 einen Schnitt durch eine Ausführungsform mit pneumatischen Antrieb.
Embodiments of the invention are explained below with reference to the drawings. The drawings show in
  • Fig. 1 shows a section through an embodiment with an electric drive and in
  • Fig. 2 shows a section through an embodiment with a pneumatic drive.

Bei der in Fig. 1 dargestellten Ausführungsform ist eine Hohlachse 1 vorgesehen, die Lagerungen 10, 10' für eine Sprühglocke 2 mit einem Rotor 5, einem Stator 11 sowie einer dynamischen Dichtung 20 un eine Stoffbuchse 16 trägt. Eine elektrische Zuleitung 8 für den Stator 11 wird in einer Nut 17 auf der Hohlachse 1 durch das Lager 10' geführt. Die Hohlachse 1 endet in einem Diffusor 12, der durch ein Gleichrichtsieb 14 abgeschlossen ist. Der Einlauf des Diffusors 12 ist als Ventilsitz 3 ausgebildet, an dem der Flüssigkeitsstrom mit Hilfe einer Ventilnadel 4 abgesperrt werden kann.In the embodiment shown in FIG. 1, a hollow axis 1 is provided which supports bearings 10, 10 'for a spray bell 2 with a rotor 5, a stator 11 and a dynamic seal 20 and a fabric bushing 16. An electrical lead 8 for the stator 11 is guided in a groove 17 on the hollow axis 1 through the bearing 10 '. The hollow axis 1 ends in a diffuser 12, which is closed by a rectifying sieve 14. The inlet of the diffuser 12 is designed as a valve seat 3, on which the liquid flow can be shut off using a valve needle 4.

Die Glockeninnenkontur trägt zur Übertragung der Corioliskraft eine Radialverzahnung 15. Druckluftdüsen 9 eines Düsenkranzes 6 erzeugen einen kreisringförmigen Luftschleier, der dem an einer Sprühkante 13 der Sprühglocke 2 versprühten Lacknebel einen Axialschub aufprägt. Die Einführung des zu versprühenden Lackes erfolgt über eine Leitung 7.The bell inner contour carries a radial toothing 15 for the transmission of the Coriolis force. Compressed air nozzles 9 of a nozzle ring 6 produce an annular air curtain which imparts an axial thrust to the paint mist sprayed on a spray edge 13 of the spray bell 2. The paint to be sprayed is introduced via a line 7.

Bei der in Fig. 2 dargestellten Ausführungsform ist anstelle des elektrischen Antriebes ein pneumatischer Antrieb mit Turbinenrotor 18 und einem Düsenring 19 vorgesehen.In the embodiment shown in FIG. 2, a pneumatic drive with a turbine rotor 18 and a nozzle ring 19 is provided instead of the electric drive.

Claims (5)

1. A process for the electrostatic coating of articles with fluids, in particular with fluid paint, by passing the fluid to a spray bell under high voltage and rotating at high speed, namely at between 15,000 and 60,000 r.p.m., and flinging the fluid from the spray edge of the spray bell with the aid of a ring-shaped air jacket onto the article to be coated, characterised in that, in the axial centre of the rotating spray bell, the fluid is passed in the axial direction thereof and in free flight into the interior of the bell, in the course of which its transport speed is retarded to almost zero and is exposed to the toroidal vortext forming there and is passed by the toroidal vortex towards the inner surface of the rotating spray bell.
2. A device for the electrostatic coating of articles with fluids, in particular with fluid paint, comprising a spray bell (2) rotating around a fixed hollow axle (1) and having a system for the central supply of fluid and a number of compressed air jets (9) surrounding the spray bell (2), characterised in that the hollow axle's (1) exit opening ending in the centre of the spray bell base opens out wide towards the interior of the bell, and a diffuser (12) is provided in the zone of the hollow axle end.
3. A device according to Claim 2, characterised in that, viewed in the direction of flow, a rectifier sieve (14) follows the diffuser (12) in the flow path of the fluid.
4. A device according to Claims 2 and 3, characterised in that the inner surface of the spray bell (2) is provided with a set of radial teeth (15), so that energy is transferred from the spray bell (2) to the toroidal vortex and the fluid in a mechanically positive manner.
5. A device according to Claim 2, characterised in that the compressed air jets (9) are arranged in the rear zone of the spray bell (2).
EP81100609A 1980-02-15 1981-01-28 Method and apparatus for the electrostatic coating of articles by means of a fluid Expired EP0034278B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT81100609T ATE9203T1 (en) 1980-02-15 1981-01-28 METHOD AND DEVICE FOR ELECTROSTATIC COATING OF OBJECTS WITH A FLUID.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3005677A DE3005677C2 (en) 1980-02-15 1980-02-15 Method and device for the electrostatic coating of objects with liquids
DE3005677 1980-02-15

Related Child Applications (2)

Application Number Title Priority Date Filing Date
EP83102488A Division EP0089043A3 (en) 1981-01-28 1981-01-28 Method and apparatus for coating objects electronically with fluids
EP83102488.0 Division-Into 1983-03-14

Publications (3)

Publication Number Publication Date
EP0034278A2 EP0034278A2 (en) 1981-08-26
EP0034278A3 EP0034278A3 (en) 1981-12-16
EP0034278B1 true EP0034278B1 (en) 1984-09-05

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EP81100609A Expired EP0034278B1 (en) 1980-02-15 1981-01-28 Method and apparatus for the electrostatic coating of articles by means of a fluid

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US (1) US4402991A (en)
EP (1) EP0034278B1 (en)
JP (1) JPS56141870A (en)
AT (1) ATE9203T1 (en)
BR (1) BR8100890A (en)
DE (2) DE3005677C2 (en)
DK (1) DK157903C (en)
ES (1) ES499449A0 (en)
MX (1) MX149160A (en)
ZA (1) ZA81929B (en)

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Also Published As

Publication number Publication date
DK157903B (en) 1990-03-05
ATE9203T1 (en) 1984-09-15
US4402991A (en) 1983-09-06
ES8206222A1 (en) 1982-08-16
DK157903C (en) 1990-08-27
DK60381A (en) 1981-08-16
MX149160A (en) 1983-09-07
DE3165801D1 (en) 1984-10-11
ES499449A0 (en) 1982-08-16
EP0034278A2 (en) 1981-08-26
DE3005677A1 (en) 1981-08-20
ZA81929B (en) 1982-03-31
DE3005677C2 (en) 1982-06-24
JPS56141870A (en) 1981-11-05
EP0034278A3 (en) 1981-12-16
BR8100890A (en) 1981-08-25

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