EP0245849B1 - Sprayer for the electrostatic coating of objects - Google Patents

Sprayer for the electrostatic coating of objects Download PDF

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Publication number
EP0245849B1
EP0245849B1 EP87106943A EP87106943A EP0245849B1 EP 0245849 B1 EP0245849 B1 EP 0245849B1 EP 87106943 A EP87106943 A EP 87106943A EP 87106943 A EP87106943 A EP 87106943A EP 0245849 B1 EP0245849 B1 EP 0245849B1
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EP
European Patent Office
Prior art keywords
sprayer
spray head
shield
coated
article
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 - Lifetime
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EP87106943A
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German (de)
French (fr)
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EP0245849A3 (en
EP0245849A2 (en
Inventor
Rolf Schneider
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.)
Mahle Behr Industry GmbH and Co KG
Original Assignee
Behr Industrieanlagen GmbH and Co KG
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Publication of EP0245849A3 publication Critical patent/EP0245849A3/en
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    • 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
    • B05B5/053—Arrangements for supplying power, e.g. charging power
    • B05B5/0533—Electrodes specially adapted therefor; Arrangements of electrodes
    • 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
    • B05B5/001—Electrostatic spraying apparatus; Spraying apparatus with means for charging the spray electrically; Apparatus for spraying liquids or other fluent materials by other electric means incorporating means for heating or cooling, e.g. the material to be sprayed

Definitions

  • the invention relates to an atomizer according to the preamble of claim 1.
  • Known rotary atomizers e.g. serve for electrostatic coating of vehicle bodies, are contaminated in operation by the sprayed coating material.
  • the bell-plate jacket, the area of the drive shaft between the spray bell and the front housing part containing the shaft bearing, and the outer surfaces of this housing part itself are particularly at risk.
  • the undesired precipitation is not only lost for the object to be coated, but can in part be released during operation and only later hike to the object, which then eg becomes significantly dirty when changing colors.
  • the known atomizers therefore have to be cleaned frequently and regularly in a relatively laborious and time-consuming manner, which means long periods of non-operation and a corresponding impairment, especially of the large-scale coating.
  • the invention has for its object to provide an atomizer, the outer areas containing the drive and / or the storage of the spray head tend less to fogging by coating material than before and, if necessary, can be cleaned more easily.
  • the rotating cover which can expediently be an extension of the bell plate or the like via the front housing end, could in itself be cleaned much more easily than fixed housing surfaces, for example by spraying a solvent onto the cover. Surprisingly, it has been shown that there is almost no self-contamination of the rotating parts (cover and spray head). This may be due to the air currents generated by the rotation.
  • a rotary atomizer is known per se, the rotating spray head of which has an axially projecting cylindrical projection at its end facing away from the object to be coated, which closely encloses and also rotates around a cylindrical projection of the housing part containing the bearing (EP-A 0120648).
  • the purpose of this construction is to seal an ink chamber formed between the housing and the spray head to the outside.
  • the sprayed-off paint particles are charged by a bell electrode located inside the spray head and an additional electrode arranged outside with a small radial distance, which is surrounded by a further outer electrode serving to repel the paint particles.
  • the cylindrical housing attachment surrounded by the spray head attachment does not lie in an area in which there is a particular risk of contamination from the sprayed coating material.
  • This exemplary embodiment is an atomizer device which is particularly suitable for coating vehicle bodies with so-called water-based paints and has a rotary atomizer whose spray head 2, which is provided with a bell cup 3, can be mounted on a hollow shaft construction 4 containing a paint supply line, which is known in the front part 5 the housing of the atomizer is mounted.
  • the spray head 2 is grounded during operation, so it is at the same potential as the body to be coated.
  • a plurality of outer electrodes 6 are used, which are inserted at their rear end into an annular body 7 of insulating material surrounding the atomizer housing at a distance, in which an electrical conductor 8, which connects the electrodes to one another and is connected to a high-voltage line, against them the face of the ring body facing the body is arranged isolated.
  • the arrangement and the mutual spacing of the electrodes are selected so that no significant deposit of coating material occurs on the end face of the ring body 7 during operation.
  • the electrodes can be expediently arranged in pins 9 made of insulating material and projecting axially from the end face of the ring body 7.
  • outer electrodes distributed radially around the spray head could also be used be provided, which are each arranged on their own radially projecting holders from the housing, as is known from DE-A 34 29 075.
  • the invention is also suitable for spray devices in which the spray head itself is placed at high voltage potential.
  • a rotating cover 10 is provided for the front part 5 of the atomizer housing, the outer surfaces of which, including the end face, lie in an area where there is a risk of contamination from the coating material sprayed from the bell cup 3.
  • the generally cup-shaped cover 10 can consist of metal, sits coaxially on the shaft construction 4 with a central opening of its bottom part 11 and is connected to it by e.g. two axial drive pins 12 connected in a rotationally secured manner.
  • the pins 12 of the cover 10 can easily be inserted into axial bores in a corresponding end face of the shaft construction 4 without tools.
  • the cover 10 is then fastened in a nut-like manner by means of a thread on the bell plate 3 screwed onto the shaft construction 4.
  • the cover could also be integrally formed on the bell plate. Due to the described construction of the cover 10 and the bell plate 3 as two separate components, these may be Much easier to assemble on the drive shaft than a one-piece component (because you can hold the shaft with the cover when screwing on the bell cup).
  • the generally sleeve-shaped part 14 of the cover 10 concentrically surrounds the cylindrical with a certain play Outer surface of the housing part 5 and extends to a radially projecting housing part 20, the end face facing the spray head contains an annular slot 21 into which the annular rear edge of the sleeve-shaped cover part 14 engages all around.
  • This arrangement which forms a type of labyrinth seal, prevents the penetration of coating material into the space between the cover 10 and the housing part 5, especially if compressed air is conducted into the slot 21.
  • the bell plate 3 of the spray head 2 has, as shown, a sleeve-shaped outer wall 15, the outer surface of which is to be flush with the outer surface of the cover 10. Even better than with a cylindrical cover with a radially constant outer diameter, the deposition of coating material on the cover is avoided if its outer diameter is steadily smaller towards the rear, which is probably due to the corresponding changing peripheral speeds. The conical widening of the outer diameter continues forward on the outer wall 15 of the bell cup 3 up to the vicinity of the spraying edge 16.
  • outlet openings 22 of the housing part 20 open. Air can escape through these openings, which on the one hand can serve as guiding air for supporting and shaping the spray jets in the direction of the object to be coated. On the other hand, the air emerging at this point can also contribute to the support and stabilization of the pollution-preventing air flows on and around the rotating cover 10, or may even be required.
  • At least one outlet opening for a liquid or gaseous cleaning agent for the cover opens at the rear end of the cover 10.
  • This can be the aforementioned air outlet openings 22 or separate openings 23.
  • a separate cleaning device (not shown) which can be moved along its outer surface can be arranged for cleaning the cover 10.
  • the cover 10 could also be rotatably supported and driven separately from the spray bell.
  • One possibility for driving the cover enclosing the housing part 5 would be, for example, air nozzles arranged at its rear end.
  • the housing part enclosed by the rotating cover 10 is the part containing the bearings of the spray head 2.
  • the axial length of the cover i.e. the length of the covered part of the housing is at least as large as half (maximum) outer diameter of the spray head 2.

Landscapes

  • Electrostatic Spraying Apparatus (AREA)

Description

Die Erfindung betrifft einen Zerstäuber gemäß dem Oberbegriff des Anspruchs 1.The invention relates to an atomizer according to the preamble of claim 1.

Bekannte Rotationszerstäuber , die z.B. zum elektrostatischen Beschichten von Fahrzeugkarossen dienen, werden im Betrieb durch das eigene abgesprühte Beschichtungsmaterial verschmutzt. Gefährdet sind insbesondere der Glockentellermantel, der Bereich der Antriebswelle zwischen der Sprühglocke und dem die Wellenlagerung enthaltenden vorderen Gehäuseteil und die Außenflächen dieses Gehäuseteils selbst. Der unerwünschte Niederschlag geht nicht nur für den zu beschichtenden Gegenstand verloren, sondern kann sich im Betrieb teilweise von selbst wieder lösen und erst später zu dem Gegenstand wandern, der dann z.B. bei einem Farbwechsel erheblich verschmutzt wird. Die bekannten Zerstäuber müssen deshalb häufig und regelmäßig in relativ mühsamer und zeitraubender Weise gereinigt werden, was lange Betriebszwangspausen und eine entsprechende Beeinträchtigung vor allem der Großserienbeschichtung bedeutet.Known rotary atomizers, e.g. serve for electrostatic coating of vehicle bodies, are contaminated in operation by the sprayed coating material. The bell-plate jacket, the area of the drive shaft between the spray bell and the front housing part containing the shaft bearing, and the outer surfaces of this housing part itself are particularly at risk. The undesired precipitation is not only lost for the object to be coated, but can in part be released during operation and only later hike to the object, which then eg becomes significantly dirty when changing colors. The known atomizers therefore have to be cleaned frequently and regularly in a relatively laborious and time-consuming manner, which means long periods of non-operation and a corresponding impairment, especially of the large-scale coating.

Diese Eigenverschmutzung ist nicht nur bei den konventionellen Rotationszerstäubern festzustellen (vgl. EP-PS 0032391), in denen das die Farbpartikel aufladende elektrostatische Feld zwischen der auf Hochspannung liegenden Sprühglocke und der geerdeten Karosse od. dgl. erzeugt wird, sondern in noch stärkerem Maße auch bei Vorrichtungen mit geerdetem Sprühkopf und Außenelektroden zur Erzeugung des elektrischen Feldes, bei denen kein der Verschmutzungsgefahr entgegenwirkender Potentialgradient zwischen dem Sprühkopf und dem zu beschichtenden Gegenstand vorhanden ist (vgl. DE-A 34 29075). Die Vorrichtungen mit Außenelektroden haben den Vorteil, sich für umweltfreundliche Lackmaterialien mit weniger organischen Bestandteilen zu eignen, die relativ stark leitfähig sind. Das Eigenverschmutzungsproblem bei Vorrichtungen mit Außenelektroden war aber bisher ein wesentliches Hindernis für die Verwendung von umweltfreundlichen Lackmaterialien.This inherent contamination is not only found in the conventional rotary atomizers (cf. EP-PS 0032391), in which the electrostatic field charging the paint particles between the high-voltage spray bell and the grounded body or the like is produced, but to an even greater extent also in devices with a grounded spray head and external electrodes for generating the electric field, in which there is no potential gradient between the spray head and the object to be coated, which counteracts the risk of contamination (cf. DE -A 34 29075). The devices with external electrodes have the advantage of being suitable for environmentally friendly coating materials with fewer organic components that are relatively highly conductive. The problem of self-pollution in devices with external electrodes has so far been a major obstacle to the use of environmentally friendly paint materials.

Der Erfindung liegt die Aufgabe zugrunde, einen Zerstäuber zu schaffen, dessen den Antrieb und/oder die Lagerung des Sprühkopfes enthaltende Außenbereiche weniger zum Beschlagen durch Beschichtungsmaterial neigen als bisher und, falls erforderlich, einfacher gereinigt werden können.The invention has for its object to provide an atomizer, the outer areas containing the drive and / or the storage of the spray head tend less to fogging by coating material than before and, if necessary, can be cleaned more easily.

Diese Aufgabe wird durch den im Anspruch 1 gekennzeichneten Zerstäuber gelöst.This object is achieved by the atomizer characterized in claim 1.

Die rotierende Abdeckung , bei der es sich zweckmäßig um eine Verlängerung des Glockentellers od. dgl. über das vordere Gehäuseende handeln kann, könnte an sich wesentlich einfacher gereinigt werden als feststehende Gehäuseflächen, beispielsweise durch Aufsprühen eines Lösungsmittels auf die Abdeckung. Überraschend hat sich aber gezeigt, daß fast überhaupt keine Eigenverschmutzung der rotierenden Teile (Abdeckung und Sprühkopf) auftritt. Dies liegt möglicherweise an den aufgrund der Rotation erzeugten Luftströmungen.The rotating cover, which can expediently be an extension of the bell plate or the like via the front housing end, could in itself be cleaned much more easily than fixed housing surfaces, for example by spraying a solvent onto the cover. Surprisingly, it has been shown that there is almost no self-contamination of the rotating parts (cover and spray head). This may be due to the air currents generated by the rotation.

Es ist an sich schon ein Rotationszerstäuber bekannt, dessen rotierender Sprühkopf an seinem dem zu beschichtenden Gegenstand abgewandten Ende einen axial vorspringenden zylindrischen Ansatz hat, welcher einen ebenfalls zylindrischen Ansatz des die Lagerung enthaltenden Gehäuseteils eng umschließt und um diesen rotiert (EP-A 0120648). Der Zweck dieser Konstruktion besteht aber im Unterschied zur Erfindung darin, eine zwischen dem Gehäuse und dem Sprühkopf gebildete Farbkammer nach außen abzudichten. Die Aufladung der abgesprühten Farbpartikel erfolgt bei dem bekannten Rotationszerstäuber durch eine innerhalb des Sprühkopfes befindliche Glockenelektrode und eine mit geringem radialen Abstand außerhalb angeordnete Zusatzelektrode, die von einer weiteren, zur Abstoßung der Farbpartikel dienenden Außenelektrode umgeben ist. Bei dieser Anordnung liegt der von dem Sprühkopfansatz umgebene zylindrische Gehäuseansatz nicht in einem Bereich, bei dem eine besondere Gefahr der Verschmutzung durch das abgesprühte Beschichtungsmaterial besteht.A rotary atomizer is known per se, the rotating spray head of which has an axially projecting cylindrical projection at its end facing away from the object to be coated, which closely encloses and also rotates around a cylindrical projection of the housing part containing the bearing (EP-A 0120648). The purpose of this construction, in contrast to the invention, is to seal an ink chamber formed between the housing and the spray head to the outside. In the known rotary atomizer, the sprayed-off paint particles are charged by a bell electrode located inside the spray head and an additional electrode arranged outside with a small radial distance, which is surrounded by a further outer electrode serving to repel the paint particles. With this arrangement, the cylindrical housing attachment surrounded by the spray head attachment does not lie in an area in which there is a particular risk of contamination from the sprayed coating material.

An dem in der Zeichnung dargestellten bevorzugten Ausführungsbeispiel wird die Erfindung näher erläutert. Es zeigen:

Fig. 1
einen mit einer rotierenden Abdeckung versehenen Sprühkopf; und
Fig. 2
eine schematische Gesamtansicht des Zerstäubers mit Außenelektroden.
The invention is explained in more detail in the preferred exemplary embodiment illustrated in the drawing. Show it:
Fig. 1
a spray head provided with a rotating cover; and
Fig. 2
a schematic overall view of the atomizer with external electrodes.

Bei diesem Ausführungsbeispiel handelt es sich um eine insbesondere für die Beschichtung von Fahrzeugkarossen mit sogenannten Wasserlacken geeignete Zerstäubervorrichtung mit einem Rotationszerstäuber , dessen mit einem Glockenteller 3 versehener Sprühkopf 2 auf einer eine Farbzuführleitung enthaltenden Hohlwellenkonstruktion 4 montiert sein kann, die in bekannter Weise im vorderen Teil 5 des Gehäuses des Zerstäubers gelagert ist. Der Sprühkopf 2 wird im Betrieb geerdet, liegt also auf demselben Potential wie die zu beschichtende Karosse. Zum Erzeugen des erforderlichen elektrostatischen Feldes dienen eine Vielzahl von Außenelektroden 6, die an ihrem hinteren Ende in einen das Zerstäubergehäuse mit Abstand umgebenden Ringkörper 7 aus Isoliermaterial eingesetzt sind, in welchem ein die Elektroden ringartig miteinander verbindender , an eine Hochspannungsleitung angeschlossener elektrischer Leiter 8 gegen die der Karosse zugewandte Stirnfläche des Ringkörpers isoliert angeordnet ist. Die Anordnung und der gegenseitige Abstand der Elektroden sind so gewählt, daß im Betrieb kein wesentlicher Niederschlag von Beschichtungsmaterial auf der Stirnfläche des Ringkörpers 7 erfolgt. Die Elektroden können zweckmässig in fingerartig axial von der Stirnseite des Ringkörpers 7 vorspringenden Zapfen 9 aus Isoliermaterial angeordnet sein.This exemplary embodiment is an atomizer device which is particularly suitable for coating vehicle bodies with so-called water-based paints and has a rotary atomizer whose spray head 2, which is provided with a bell cup 3, can be mounted on a hollow shaft construction 4 containing a paint supply line, which is known in the front part 5 the housing of the atomizer is mounted. The spray head 2 is grounded during operation, so it is at the same potential as the body to be coated. To generate the required electrostatic field, a plurality of outer electrodes 6 are used, which are inserted at their rear end into an annular body 7 of insulating material surrounding the atomizer housing at a distance, in which an electrical conductor 8, which connects the electrodes to one another and is connected to a high-voltage line, against them the face of the ring body facing the body is arranged isolated. The arrangement and the mutual spacing of the electrodes are selected so that no significant deposit of coating material occurs on the end face of the ring body 7 during operation. The electrodes can be expediently arranged in pins 9 made of insulating material and projecting axially from the end face of the ring body 7.

Statt der dargestellten Ringelektrodenanordnung , die genauer in der deutschen Patentanmeldung P 36 09 240.1 beschrieben ist, könnten auch radial um den Sprühkopf verteilte Außenelektroden vorgesehen sein, die jeweils an eigenen radial vom Gehäuse abstehenden Haltern angeordnet sind, wie dies aus der DE-A 34 29 075 bekannt ist. Die Erfindung eignet sich aber auch für Sprühvorrichtungen, bei denen der Sprühkopf selbst auf Hochspannungspotential gelegt wird.Instead of the ring electrode arrangement shown, which is described in more detail in German patent application P 36 09 240.1, outer electrodes distributed radially around the spray head could also be used be provided, which are each arranged on their own radially projecting holders from the housing, as is known from DE-A 34 29 075. However, the invention is also suitable for spray devices in which the spray head itself is placed at high voltage potential.

Gemäß der Erfindung ist eine rotierende Abdeckung 10 für den vorderen Teil 5 des Zerstäubergehäuses vorgesehen, dessen Außenflächen einschließlich der Stirnfläche in einem Bereich der Gefahr der Verschmutzung durch das vom Glockenteller 3 abgesprühte Beschichtungsmaterial liegt. Die darstellungsgemäß allgemein becherförmige Abdeckung 10 kann aus Metall bestehen, sitzt mit einer Mittelöffnung ihres Bodenteils 11 koaxial auf der Wellenkonstruktion 4 und ist mit dieser durch z.B. zwei axiale Mitnehmerstifte 12 verdrehungsgesichert verbunden. Die Stifte 12 der Abdeckung 10 können ohne Werkzeug einfach in axiale Bohrungen in einer entsprechenden Stirnfläche der Wellenkonstruktion 4 eingesetzt werden. Durch den als gesondertes Bauteil z.B. mutterartig mittels eines Gewindes auf die Wellenkonstruktion 4 geschraubten Glockenteller 3 wird die Abdeckung 10 dann befestigt.According to the invention, a rotating cover 10 is provided for the front part 5 of the atomizer housing, the outer surfaces of which, including the end face, lie in an area where there is a risk of contamination from the coating material sprayed from the bell cup 3. The generally cup-shaped cover 10 according to the illustration can consist of metal, sits coaxially on the shaft construction 4 with a central opening of its bottom part 11 and is connected to it by e.g. two axial drive pins 12 connected in a rotationally secured manner. The pins 12 of the cover 10 can easily be inserted into axial bores in a corresponding end face of the shaft construction 4 without tools. Through the as a separate component e.g. The cover 10 is then fastened in a nut-like manner by means of a thread on the bell plate 3 screwed onto the shaft construction 4.

Stattdessen könnte die Abdeckung auch dem Glockenteller einstückig angeformt sein. Durch die beschriebene Konstruktion der Abdeckung 10 und des Glockentellers 3 als zwei getrennte Bauteile sind diese aber u.U. wesentlich einfacher an der Antriebswelle montierbar als ein einstückiges Bauteil (weil man beim Aufschrauben des Glockentellers die Welle mit der Abdeckung festhalten kann).Instead, the cover could also be integrally formed on the bell plate. Due to the described construction of the cover 10 and the bell plate 3 as two separate components, these may be Much easier to assemble on the drive shaft than a one-piece component (because you can hold the shaft with the cover when screwing on the bell cup).

Der allgemein hülsenförmige Teil 14 der Abdeckung 10 umschließt mit einem gewissen Spiel konzentrisch die zylindrische Außenfläche des Gehäuseteils 5 und reicht bis zu einem radial weiter vorspringenden Gehäuseteil 20, dessen dem Sprühkopf zugewandte Stirnfläche einen ringförmigen Schlitz 21 enthält, in den der ringförmige hintere Rand des hülsenförmigen Abdeckungsteils 14 umlaufend eingreift. Durch diese eine Art von Labyrinthdichtung bildende Anordnung wird das Eindringen von Beschichtungsmaterial in den Zwischenraum zwischen der Abdeckung 10 und dem Gehäuseteil 5 vermieden, vor allem, wenn man Druckluft in den Schlitz 21 leitet.The generally sleeve-shaped part 14 of the cover 10 concentrically surrounds the cylindrical with a certain play Outer surface of the housing part 5 and extends to a radially projecting housing part 20, the end face facing the spray head contains an annular slot 21 into which the annular rear edge of the sleeve-shaped cover part 14 engages all around. This arrangement, which forms a type of labyrinth seal, prevents the penetration of coating material into the space between the cover 10 and the housing part 5, especially if compressed air is conducted into the slot 21.

Der Glockenteller 3 des Sprühkopfes 2 hat darstellungsgemäß eine hülsenförmige Außenwand 15, deren Außenfläche lückenlos mit der Außenfläche der Abdeckung 10 fluchten soll. Noch besser als durch eine zylindrische Abdeckung mit radial gleichbleibendem Außendurchmesser wird die Ablagerung von Beschichtungsmaterial auf der Abdeckung vermieden, wenn ihr Außendurchmesser darstellungsgemäß nach hinten stetig kleiner wird, was vermutlich an den sich entsprechend ändernden Umfangsgeschwindigkeiten liegt. Die konische Erweiterung des Außendurchmessers setzt sich nach vorne auf der Außenwand 15 des Glockentellers 3 bis in die Nähe der Absprühkante 16 fort.The bell plate 3 of the spray head 2 has, as shown, a sleeve-shaped outer wall 15, the outer surface of which is to be flush with the outer surface of the cover 10. Even better than with a cylindrical cover with a radially constant outer diameter, the deposition of coating material on the cover is avoided if its outer diameter is steadily smaller towards the rear, which is probably due to the corresponding changing peripheral speeds. The conical widening of the outer diameter continues forward on the outer wall 15 of the bell cup 3 up to the vicinity of the spraying edge 16.

Radial außerhalb, aber in der Nähe der Außenfläche der Abdeckung 10 münden Austrittsöffnungen 22 des Gehäuseteils 20. Durch diese Öffnungen kann Luft austreten, die einerseits als Lenkluft zur Unterstützung und Formung der Sprühstrahlen in Richtung zum zu beschichtenden Gegenstand dienen kann. Andererseits kann die an dieser Stelle austretende Luft aber auch zur Unterstützung und Stabilisierung der die Verschmutzung verhindernden Luftströmungen an und um die rotierende Abdeckung 10 beitragen oder sogar erforderlich sein.Radially outside, but in the vicinity of the outer surface of the cover 10, outlet openings 22 of the housing part 20 open. Air can escape through these openings, which on the one hand can serve as guiding air for supporting and shaping the spray jets in the direction of the object to be coated. On the other hand, the air emerging at this point can also contribute to the support and stabilization of the pollution-preventing air flows on and around the rotating cover 10, or may even be required.

Es kann auch zweckmässig sein, daß am hinteren Ende der Abdeckung 10 mindestens eine Austrittsöffnung für ein flüssiges oder gasförmiges Reinigungsmittel für die Abdeckung mündet. Hierbei kann es sich um die erwähnten Luftaustrittsöffnungen 22 oder um gesonderte Öffnungen 23 handeln. Ferner kann zum Reinigen der Abdeckung 10 eine längs ihrer Außenfläche bewegbare gesonderte Reinigungsvorrichtung (nicht dargestellt) angeordnet werden.It may also be expedient that at least one outlet opening for a liquid or gaseous cleaning agent for the cover opens at the rear end of the cover 10. This can be the aforementioned air outlet openings 22 or separate openings 23. Furthermore, a separate cleaning device (not shown) which can be moved along its outer surface can be arranged for cleaning the cover 10.

U.U. ist es nicht notwendig, daß die Abdeckung 10 mit derselben relativ hohen Drehzahl rotiert wie die Sprühglocke. Statt der oben beschriebenen Ausführungsform könnte man in solchen Fällen die Abdeckung auch getrennt von der Sprühglocke drehbar lagern und antreiben. Eine Möglichkeit zum Antrieb der den Gehäuseteil 5 umschließenden Abdeckung wären beispielsweise an ihrem hinteren Ende angeordnete Luftdüsen.U.U. it is not necessary for the cover 10 to rotate at the same relatively high speed as the spray bell. In such cases, instead of the embodiment described above, the cover could also be rotatably supported and driven separately from the spray bell. One possibility for driving the cover enclosing the housing part 5 would be, for example, air nozzles arranged at its rear end.

Da durch die ggf. mit dem Sprühkopf verbundene Abdeckung 10 die Lager der Wellenkonstruktion 4 etwas stärker belastet werden als bisher, kann eine besondere Kühlung der Lager, vorzugsweise durch Druckluft erforderlich sein.Since the bearing of the shaft construction 4 is loaded somewhat more than before by the cover 10, which may be connected to the spray head, special cooling of the bearings, preferably by compressed air, may be required.

Gemäß dem beschriebenen Ausführungsbeispiel handelt es sich bei dem von der rotierenden Abdeckung 10 umschlossenen Gehäuseteil um den die Lager des Sprühkopfes 2 enthaltenden Teil. Es kann aber in anderen Fällen auch zweckmäßig sein, andere Gehäuseteile erfindungsgemäß abzudecken, die in einem Bereich der Gefahr einer Verschmutzung durch das abgesprühte Beschichtungsmaterial liegen. In der Regel ist die axiale Länge der Abdeckung, d.h. die Länge des abgedeckten Teils des Gehäuses mindestens so groß wie der halbe (maximale) Außendurchmesser des Sprühkopfes 2.According to the exemplary embodiment described, the housing part enclosed by the rotating cover 10 is the part containing the bearings of the spray head 2. In other cases, however, it can also be expedient to cover other housing parts according to the invention which are in a range of the risk of contamination by the sprayed-off coating material. As a rule, the axial length of the cover, i.e. the length of the covered part of the housing is at least as large as half (maximum) outer diameter of the spray head 2.

Claims (16)

  1. Sprayer for electrostatically coating articles with a spray head (2), which is rotatably mounted on or in a housing portion (5) and whose external surface is situated in a region at risk of contamination by the sprayed coating material, particularly with a spray head (2) which, in use, is at the same low potential as the article to be coated and electrodes (6) arranged radially outside the spray head (2) for charging the sprayed particles, characterised in that a rotating shield (10) is provided for the housing portion (5) lying within the contamination region.
  2. Sprayer as claimed in Claim 1, characterised in that the rotating shield (10) surrounds the housing portion (5) containing the bearing of the spray head (2).
  3. Sprayer as claimed in Claim 1, characterised in that the shield (10) is rigidly connected to the spray head (2).
  4. Sprayer as claimed in Claim 1 or 2, characterised in that the shield (10) is a separate component from the bell plate (3) of the spray head (2).
  5. Sprayer as claimed in Claim 4, characterised in that the shield (10) is connected rotationally fixedly to the drive shaft construction (4) of the spray head (2) by carrier pins (12) or in another manner and is secured by the screwed-on bell plate (3).
  6. Sprayer as claimed in one of the preceding claims, characterised in that the external diameter of the shield (10) becomes steadily smaller in the direction opposite to the article to be coated.
  7. Sprayer as claimed in one of the preceding claims, characterised in that the external surfaces of the shield (10) and of the spray head (2) continuously extend with one another.
  8. Sprayer as claimed in Claim 7, characterised in that the bell plate (3) of the spray head (2) has a sleeve-shaped outer wall (15) whose external surface has a conically increasing diameter in the direction towards the article to be coated and forms a continuation of the outer surface of the shield (10) without interruption.
  9. Sprayer as claimed in Claim 1, characterised in that the shield is rotatable relative to the spray head.
  10. Sprayer as claimed in one of the preceding claims, characterised in that at least one air outlet opening (22) opens out at the end of the shield (10) directed away from the article to be coated.
  11. Sprayer as claimed in one of the preceding claims, characterised in that at least one outlet opening (23) for a liquid or gaseous cleaning agent opens out at the end of the shield directed away from the article to be coated.
  12. Sprayer as claimed in one of the preceding claims, characterized in that the shield (10) extends around within an annular recess (21) in the housing with the annular end which is directed away from the article to be coated of its sleeve-shaped portion (14) surrounding the housing portion (5).
  13. Sprayer as claimed in Claim 12, characterized in that compressed air is introduced into the annular recess (21).
  14. Sprayer as claimed in one of the preceding claims, characterized in that the bearings of the rotating shield (10) or of the spray head are cooled by compressed air.
  15. Sprayer as claimed in one of the preceding claims, characterized in that the axial length of the shield (10) is at least as large as half the diameter of the spray head (2).
  16. Sprayer as claimed in one of the preceding claims, characterized in that the axial length of the arrangement comprising the shield (10) and spray head (2) is at least as large as the diameter of the spray head (2).
EP87106943A 1986-05-16 1987-05-13 Sprayer for the electrostatic coating of objects Expired - Lifetime EP0245849B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3616684 1986-05-16
DE19863616684 DE3616684A1 (en) 1986-05-16 1986-05-16 SPRAYER FOR ELECTROSTATIC COATING OF OBJECTS

Publications (3)

Publication Number Publication Date
EP0245849A2 EP0245849A2 (en) 1987-11-19
EP0245849A3 EP0245849A3 (en) 1988-10-26
EP0245849B1 true EP0245849B1 (en) 1991-03-06

Family

ID=6301054

Family Applications (1)

Application Number Title Priority Date Filing Date
EP87106943A Expired - Lifetime EP0245849B1 (en) 1986-05-16 1987-05-13 Sprayer for the electrostatic coating of objects

Country Status (4)

Country Link
US (1) US4760965A (en)
EP (1) EP0245849B1 (en)
DE (2) DE3616684A1 (en)
ES (1) ES2020665B3 (en)

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Also Published As

Publication number Publication date
DE3768327D1 (en) 1991-04-11
EP0245849A3 (en) 1988-10-26
EP0245849A2 (en) 1987-11-19
DE3616684A1 (en) 1987-11-19
US4760965A (en) 1988-08-02
ES2020665B3 (en) 1991-09-01

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