EP0637466B1 - Device for the electrostatic spraying of powdery products - Google Patents

Device for the electrostatic spraying of powdery products Download PDF

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Publication number
EP0637466B1
EP0637466B1 EP94110270A EP94110270A EP0637466B1 EP 0637466 B1 EP0637466 B1 EP 0637466B1 EP 94110270 A EP94110270 A EP 94110270A EP 94110270 A EP94110270 A EP 94110270A EP 0637466 B1 EP0637466 B1 EP 0637466B1
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EP
European Patent Office
Prior art keywords
sleeve
powder
electrode
spray apparatus
contact portion
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
Application number
EP94110270A
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German (de)
French (fr)
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EP0637466A1 (en
Inventor
Karl Buschor
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Gema Switzerland GmbH
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Gema Switzerland GmbH
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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
    • B05B5/0535—Electrodes specially adapted therefor; Arrangements of electrodes at least two electrodes having different potentials being held on the discharge apparatus, one of them being a charging electrode of the corona type located in the spray or close to it, and another being of the non-corona type located outside of the path for the material
    • 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

Definitions

  • the invention relates to an electrostatic powder spray device according to the preamble of claim 1.
  • the powder spray device has a counter electrode Withdrawing free ions from the stream of sprayed Powder on.
  • Such an electrostatic spray device is known from US-PS 4 921 172.
  • the well-known powder spray device has a multi-part body, through which a powder channel passes through, on the downstream End of a spray opening for spraying the Powder is on an object to be coated. Upstream of the spray opening, but radially outside of the powder channel is one grounded annular counter electrode arranged. Instead of ground potential, the counter electrode could also be connected to another electrical potential. All that is required for the potential is that between the counter electrode and one for powder charging serving charging electrode an electrical Potential difference arises through which free ions are made the flow of atomized powder to the counter electrode be suctioned off electrostatically.
  • One or more charging electrodes for electrostatic The powder can be charged in or next to the Powder flow before or after spraying be arranged.
  • the charging electrode will connected to high voltage, which is usually can be between 10 KV and 140 KV.
  • the high voltage is generated by a high voltage generator, which in the powder spray device integrated or connected externally can be.
  • the object to be coated is connected to another electrical potential, usually at earth potential. With the sprayed powder free ions also reach the surface to be coated Object.
  • the counter electrode serves to free such To withdraw ions from the powder stream before they get onto the object to be coated. By the Removing the free ions is used in many applications achieved a better coating quality. After this The coating process becomes the coated objects placed in an oven in which the powder particles melt and form a homogeneous layer.
  • the electrostatic spray device has in use the form of an automatically controlled device elongated body, when used as a handgun Shape of a pistol.
  • the type of coating required can be Spray device with counter electrode or in another Case a spray device without counter electrode better Bring coating results.
  • the high voltage for the charging electrode is today mostly not by external high voltage generators generated, but by in the body of the sprayer integrated high voltage generator. Depending on the application can be a high high voltage or a lower one High voltage be more appropriate. This means that ever a spray device with high or lower cooking voltage is desired. To this Purposes, it is also known electrostatic Spraying devices so that the high voltage generator against another high voltage generator can be exchanged.
  • a powder sprayer with an integrated and replaceable high voltage generator is from the U.S. Patent 4,196,465.
  • the object of the invention is to solve a problem To design electrostatic powder spraying devices that they easily disassembled quickly and again can be assembled. It is also said to be simple Optionally used with or without a counter electrode can be. Another object of the invention is the powder spray device so that on a high-voltage generator integrated in it in a simple manner and quickly against another high voltage generator and / or a powder spray nozzle against another Powder spray nozzle can be replaced.
  • Powder spray device contains a body 4 electrically insulating material, one axially through it through pipe 8 made of electrically insulating Material, a downstream of the body 4 and that Tube 8 connecting intermediate piece 12 and one itself downstream nozzle 10 each electrically insulating material.
  • the tube 8 that Intermediate piece 12, a bushing 6 surrounding it and the nozzle 10 form a powder channel 14 through which one upstream rear device part 15, which is carried by the body 4, powder pneumatically to the nozzle 10 and through a spray opening formed in the nozzle 10 18 is promoted.
  • the powder comes through the spray opening 18 sprayed onto an object to be coated.
  • the Intermediate piece 12 extends in the form of a narrow Plate through the powder channel 14 so that the powder on Intermediate piece 12 can flow axially past.
  • the Intermediate piece 12 carries an acicular Charging electrode 20, the electrode tip 21 short upstream of the spray opening 18 from an in Intermediate piece 12 formed air channel 24 protrudes.
  • the Air duct 24 supplied compressed air flows on the Electrode tip 21 over into the powder channel 14 and in the spray opening 18.
  • the charging electrode 20 is axial arranged with respect to the powder channel 14 and her upstream aft end is over at least one electrical resistance 26 and one upstream adjoining electrical plug connection 28 and 29 to a front high voltage output 30 of a high voltage generator 32 connected.
  • the high voltage generator 32 is preferably a known cascade connection from electrical resistors and electrical capacitors. High voltage generators of this type are, for example known from US-PS 4 196 465.
  • the high voltage generator 32 has a rear low voltage input 34 for connection to an external electrical low voltage source on.
  • the high voltage generator 32 is in a cavity 36 formed in the body 4, which extends parallel to the powder channel 14 and in a downstream end face 48 of the body 4 flows. By axially pulling out the intermediate piece 12 the connector 28 and 29 is disconnected.
  • the cavity 36 is open to the intermediate piece 12, so that after Separation of the electrical connector 28, 29 of the High voltage generator 32 pulled out of the cavity 36 and against another high voltage generator can be exchanged.
  • the high voltage generator 32 generated high voltage electrical causes Electrode 20 and by the air flowing past it the air duct 24 an electrostatic charge of the Powder.
  • the body 4 is provided with an external thread 40 which is a sleeve 42 made of electrically insulating Material is screwed with its internal thread 41.
  • the Sleeve 42 is placed over the nozzle 10 and presses with against a rearward facing radial end face 44 a forwardly facing radial face 46 of the nozzle 10.
  • the sleeve 42 tensions with its radial end face 44 the nozzle 10 and the intermediate piece 12 against the forward-facing radial face 48 of body 4.
  • the intermediate piece 12 and of the high voltage generator 32 thus only needs that Sleeve 42 to be unscrewed from the body 4.
  • the sleeve 42 is beyond its internal thread 41 extended at the rear by a sleeve section 50.
  • This with respect to the thread 41 rear sleeve portion 50 carries a plurality of rings around the powder channel 14 needle-shaped counter electrodes 52 arranged around it Counter electrodes 52 are located within radial Bores 56 formed in the sleeve portion 50 and open into its outer surface 58.
  • the holes 56 can be connected in the Sleeve 42 to be connected to a compressed air source, whose compressed air flows over the counter electrodes 52 and thereby powder and dust from the counter electrodes 52 holds.
  • An electrical conduction path 60 extends from an electrical connection element 62 on the Back of the rear device part 15 in essentially parallel to the powder channel 14 to the radially inner ends of the counter electrodes 52 so that the Counter electrodes 52 via the connecting element 62 to electrical potential, preferably earth potential, can be connected.
  • This electrical potential differs in this way from the electrical high-voltage potential the charging electrode 20 that the Counter electrodes 52 free ions from the stream of sputtered Powder downstream of spray opening 18 tighten, which then via conduit 60 and that Connection element 62 are neutralized.
  • the counter electrodes 52 are as close as possible to the spray opening 18 to the best electrical efficiency to have. In practice, however, the counter electrodes are 52 corresponding to Fig.
  • the electrical conduction path 60 is related to one on the flow direction of the powder in the powder channel 14 upstream rear conduit section 64 and one divided downstream front pipe section 66.
  • the two line sections 64 and 66 are by a Ring contact connection 68 interconnected.
  • the ring contact connection 68 consists essentially of one Contact ring 70 made of electrically conductive material and a contacting device 72.
  • the contacting device 72 lies against the contact ring 70 and is with the rear line section 64 electrically connected.
  • Of the Contact ring 70 is in the inner peripheral surface 74 near the rear end of the rear sleeve portion 50 housed and fastened and with the front pipe section 66 electrically connected.
  • This front one Line section 66 extends axially parallel to Powder channel 14 between the two adjacent Shell surfaces 78 and 79 of two concentric to each other arranged and non-rotatably connected Pipes 80 and 81, which together form the rear Form sleeve section 50.
  • Die Contacting device 72 sits in one in the Recess 84 formed on the outer surface of the body 4 the mouth of a bore 63 and is through a Rod made of electrically conductive material connected to the rear pipe section 64 forms.
  • the rod 64 extends through the bore 63 and is electrically connected to the connection element 62.
  • the rod 64 and the connecting element 62 form one Connector.
  • the bore 63 is formed in the body 4 and runs parallel to the powder channel 14.
  • the non-rotatable Contacting device 72 is stationary on the body 4 arranged and lies from the inside to the outside of the contact ring 70 on.
  • the rod 64 in the bore 63 prevents Rotating the contacting device 72 around the powder channel 14.
  • the contact ring 70 and the sleeve section 50 overlap the non-rotatable contacting device 72.
  • the contact device 72 is not the Powder channel 14 is rotatable, but arranged stationary is, it has at each rotational position of the sleeve 42 with the Contact ring 70 mechanical and electrical contact, there the contact ring 70 around the entire inner circumference of the Sleeve 42 extends.
  • a Axial stop 86 formed, behind which the Contacting device 72 about the longitudinal axis of the rod 64 is pivoted and behind which it from the sleeve 42nd is held. This makes the contacting device 72 from the mouth of the bore 63 and the axial stop 86 in a certain axial position relative to the Contact ring 70 held.
  • the contacting device 72 um the longitudinal axis of the rod 64 via the axial stop 86 be swung out and then together with the rod 64 are pulled axially out of the body 4.
  • FIG. 2 shows the contacting device 72 and the rod 64 seen in the direction of an arrow II in Fig. 1 behind the Axial stop 86 in a locked operating position.
  • FIG. 3 shows the contacting device 72 from FIG. 2 in an unlocked removal position, in which it is after Removal of the sleeve 42 in the direction of one in FIG. 2 arrow 88 shown about the longitudinal axis of the rod 64 the height of the axial stop 86 was pivoted out. From the unlocked removal position of Fig. 3, the Contacting device 72 together with the rod 64 the axial stop 86 parallel to the powder channel 14 are pulled out of the body 4 to the front.
  • the non-rotatably arranged relative to the contact ring 70 Contacting device 72 consists of a contact housing 90 made of electrically conductive material, one of the Contact ring 70 contacting ball 91 made of electrical conductive material, one screwed into the contact housing 90 Screw 92 and a spring 93 each electrically conductive material.
  • the spring 93 is between the screw 92 and the contact ball 91 clamped and presses the contact ball 91 elastically against the Contact ring 70.
  • the rear line section 64 forming rod made of electrically conductive material is with the contact housing 90 mechanically connected and thus with the contact ball 91 electrically connected.
  • the nozzle 10 can be easily removed by removing the Sleeve 42 can be exchanged for another nozzle, which is circular or slit-shaped in cross section Can have spray opening 18.
  • Counter electrodes 52 are preferably the sleeve 42, which counter electrodes 52 against another sleeve 142 exchanged, which according to FIG. 5 no counter electrodes 52 has.
  • the contact ring 70 is located in the end section 146 on the enlarged Inner diameter 147 and the contacting device 72 extends into end portion 146 to Contact ring 70. This allows the other sleeve 142 of 5 is not pushed over the contacting device 72 will. The other sleeve 142 can only on the body 4 properly attached if the Contacting device 72 and the rod 64 from the Powder spray device can be removed.

Landscapes

  • Electrostatic Spraying Apparatus (AREA)
  • Application Of Or Painting With Fluid Materials (AREA)

Abstract

Electrostatic powder-spraying device with a charging electrode (20) for the electrostatic charging of powder for the spray-coating of articles and with at least one counterelectrode (52) for the electrostatic extraction of free ions from the stream of sprayed powder. An electrical conduction path (60) for connecting the counterelectrode (52) to a different electrical potential from the charging electrode (20) contains a ring-contact connection (68). The powder-spraying device can be demounted in a simple way for cleaning and can also optionally be used without a counterelectrode (52). <IMAGE>

Description

Die Erfindung betrifft eine elektrostatische Pulversprühvorrichtung gemäß dem Oberbegriff von Anspruch 1.The invention relates to an electrostatic powder spray device according to the preamble of claim 1.

Die Pulversprühvorrichtung weist eine Gegenelektrode zum Abziehen von freien Ionen aus dem Strom von versprühtem Pulver auf. Eine solche elektrostatische Sprühvorrichtung ist aus der US-PS 4 921 172 bekannt. Die bekannte Pulversprühvorrichtung hat einen mehrteiligen Körper, durch welchen ein Pulverkanal hindurchführt, an dessen stromabwärtigen Ende sich eine Sprühöffnung zum Sprühen des Pulvers auf einen zu beschichtenden Gegenstand befindet. Stromaufwärts der Sprühöffnung, jedoch radial außerhalb des Pulverkanals, ist eine geerdete ringförmige Gegenelektrode angeordnet. Statt an Erdpotential könnte die Gegenelektrode auch an ein anderes elektrisches Potential angeschlossen sein. Erforderlich für das Potential ist lediglich, daß zwischen der Gegenelektrode und einer zur Pulveraufladung dienenden Aufladungselektrode eine elektrische Potentialdifferenz entsteht, durch welche freie Ionen aus dem Strom des zerstäubten Pulvers zur Gegenelektrode hin elektrostatisch abgesaugt werden.The powder spray device has a counter electrode Withdrawing free ions from the stream of sprayed Powder on. Such an electrostatic spray device is known from US-PS 4 921 172. The well-known powder spray device has a multi-part body, through which a powder channel passes through, on the downstream End of a spray opening for spraying the Powder is on an object to be coated. Upstream of the spray opening, but radially outside of the powder channel is one grounded annular counter electrode arranged. Instead of ground potential, the counter electrode could also be connected to another electrical potential. All that is required for the potential is that between the counter electrode and one for powder charging serving charging electrode an electrical Potential difference arises through which free ions are made the flow of atomized powder to the counter electrode be suctioned off electrostatically.

Gegenelektroden sind auch aus der US-PS 4 774 102 bekannt.Counter electrodes are also known from US Pat. No. 4,774,102.

Eine oder mehrere Aufladungselektroden zum elektrostatischen Aufladen des Pulvers können im oder neben dem Pulverstrom vor seiner Versprühung oder nach seiner Versprühung angeordnet sein. Die Aufladungselektrode wird an Hochspannung angeschlossen, welche üblicherweise zwischen 10 KV und 140 KV liegen kann. Die Hochspannung wird von einem Hochspannungserzeuger erzeugt, welcher in die Pulversprühvorrichtung integriert oder extern angeschlossen sein kann. Der zu beschichtende Gegenstand ist an ein anderes elektrisches Potential angeschlossen, üblicherweise an Erdpotential. Mit dem versprühten Pulver gelangen auch freie Ionen auf den zu beschichtenden Gegenstand. Die Gegenelektrode dient dazu, solche freien Ionen aus dem Pulverstrom heraus abzuziehen, bevor sie auf den zu beschichtenden Gegenstand gelangen. Durch das Entfernen der freien Ionen wird bei vielen Anwendungsfällen eine bessere Beschichtungsqualität erzielt. Nach dem Beschichtungsvorgang werden die beschichteten Gegenstände in einen Ofen gebracht, in welchem die Pulverpartikel schmelzen und eine homogene Schicht bilden.One or more charging electrodes for electrostatic The powder can be charged in or next to the Powder flow before or after spraying be arranged. The charging electrode will connected to high voltage, which is usually can be between 10 KV and 140 KV. The high voltage is generated by a high voltage generator, which in the powder spray device integrated or connected externally can be. The object to be coated is connected to another electrical potential, usually at earth potential. With the sprayed powder free ions also reach the surface to be coated Object. The counter electrode serves to free such To withdraw ions from the powder stream before they get onto the object to be coated. By the Removing the free ions is used in many applications achieved a better coating quality. After this The coating process becomes the coated objects placed in an oven in which the powder particles melt and form a homogeneous layer.

Die elektrostatische Sprühvorrichtung hat bei Verwendung als automatisch gesteuerte Vorrichtung die Form eines länglichen Körpers, bei Verwendung als Handpistole die Form einer Pistole.The electrostatic spray device has in use the form of an automatically controlled device elongated body, when used as a handgun Shape of a pistol.

Je nach Art des zu beschichtenden Gegenstandes und der Art der gewünschten Beschichtung kann in einem Fall eine Sprühvorrichtung mit Gegenelektrode oder in einem anderen Fall eine Sprühvorrichtung ohne Gegenelektrode bessere Beschichtungsergebnisse bringen.Depending on the type of object to be coated and the In one case, the type of coating required can be Spray device with counter electrode or in another Case a spray device without counter electrode better Bring coating results.

Ferner gibt es Anwendungsfälle, wo durch die Verwendung von schlitzförmigen anstelle von kreisrunden Düsen-Öffnungsquerschnitten bessere Beschichtungsergebnisse möglich sind, beispielsweise beim Sprühbeschichten von Vertiefungen eines Gegenstandes.There are also use cases where through the use of slot-shaped instead of circular nozzle opening cross-sections better coating results are possible, for example when spray coating Indentations of an object.

Die Hochspannung für die Aufladungselektrode wird heute meistens nicht durch externe Hochspannungserzeuger erzeugt, sondern durch in den Körper der Sprühvorrichtung integrierte Hochspannungserzeuger. Je nach Anwendungsfall kann eine hohe Hochspannung oder eine niedrigere Hochspannung zweckmäßiger sein. Dies bedeutet, daß je nach Anwendungsfall eine Sprühvorrichtung mit hoher oder mit niedrigerer Kochspannung erwünscht ist. Zu diesem Zwecke ist es auch schon bekannt, elektrostatische Sprühvorrichtungen so auszubilden, daß der Hochspannungserzeuger gegen einen anderen Hochspannungserzeuger ausgetauscht werden kann.The high voltage for the charging electrode is today mostly not by external high voltage generators generated, but by in the body of the sprayer integrated high voltage generator. Depending on the application can be a high high voltage or a lower one High voltage be more appropriate. This means that ever a spray device with high or lower cooking voltage is desired. To this Purposes, it is also known electrostatic Spraying devices so that the high voltage generator against another high voltage generator can be exchanged.

Eine Pulversprühvorrichtung mit einem integrierten und austauschbaren Hochspannungserzeuger ist aus der US-PS 4 196 465 bekannt.A powder sprayer with an integrated and replaceable high voltage generator is from the U.S. Patent 4,196,465.

Durch die Erfindung soll die Aufgabe gelöst werden, eine elektrostatische Pulversprühvorrichtung so auszubilden, daß sie auf einfache Weise schnell zerlegt und wieder zusammengebaut werden kann. Ferner soll sie auf einfache Weise wahlweise mit oder ohne Gegenelektrode verwendet werden können. Ein weiteres Ziel der Erfindung ist es, die Pulversprühvorrichtung so auszubilden, daß auf einfache Weise und schnell ein in sie integrierter Hochspannungserzeuger gegen einen anderen Hochspannungserzeuger und/oder eine Pulversprühdüse gegen eine andere Pulversprühdüse ausgetauscht werden kann.The object of the invention is to solve a problem To design electrostatic powder spraying devices that they easily disassembled quickly and again can be assembled. It is also said to be simple Optionally used with or without a counter electrode can be. Another object of the invention is the powder spray device so that on a high-voltage generator integrated in it in a simple manner and quickly against another high voltage generator and / or a powder spray nozzle against another Powder spray nozzle can be replaced.

Diese Aufgabe wird gemäß der Erfindung durch die kennzeichnenden Merkmale von Anspruch 1 gelöst.This object is achieved according to the invention by the characterizing Features of claim 1 solved.

Weitere Merkmale der Erfindung sind in den Unteransprüchen enthalten. Further features of the invention are in the subclaims contain.

Die Erfindung wird im folgenden mit Bezug auf die Zeichnungen anhand von mehreren Ausführungsformen als Beispiele beschrieben. In den Zeichnungen zeigen:

Fig. 1
einen abgebrochenen, axialen Längsschnitt durch eine Pulversprühvorrichtung nach der Erfindung mit Gegenelektroden,
Fig. 2
eine vergrößerte Ansicht in Richtung eines Pfeiles II in Fig. 1 auf eine elektrische Kontaktiervorrichtung einer Ringkontaktvorrichtung,
Fig. 3
die Kontaktiervorrichtung von Fig. 2 in herausgeschwenkter Position, nachdem eine Hülse abgeschraubt wurde,
Fig. 4
einen vergrößerten abgebrochenen axialen Längsschnitt durch eine weitere Ausführungsform einer Pulversprühvorrichtung nach der Erfindung mit einer Hülse, welche Gegenelektroden trägt,
Fig. 5
einen axialen Längsschnitt der Pulversprühvorrichtung von Fig. 3 mit einer ausgetauschten Hülse, welche keine Gegenelektroden trägt.
The invention is described below with reference to the drawings using several embodiments as examples. The drawings show:
Fig. 1
3 shows a broken, axial longitudinal section through a powder spraying device according to the invention with counter electrodes,
Fig. 2
2 shows an enlarged view in the direction of an arrow II in FIG. 1 on an electrical contacting device of a ring contact device,
Fig. 3
2 in the pivoted-out position after a sleeve has been unscrewed,
Fig. 4
2 shows an enlarged, broken-off axial longitudinal section through a further embodiment of a powder spraying device according to the invention with a sleeve which carries counter electrodes,
Fig. 5
an axial longitudinal section of the powder spraying device of Fig. 3 with an exchanged sleeve which does not have counter electrodes.

Die in den Zeichnungen dargestellte elektrostatische Pulversprühvorrichtung enthält einen Körper 4 aus elektrisch isolierendem Material, ein axial durch ihn hindurchführendes Rohr 8 aus elektrisch isolierendem Material, ein sich stromabwärts an den Körper 4 und das Rohr 8 anschließendes Zwischenstück 12 und eine sich stromabwärts daran anschließende Düse 10 je aus elektrisch isolierendem Material. Das Rohr 8, das Zwischenstück 12, eine es umgebende Buchse 6 und die Düse 10 bilden einen Pulverkanal 14, durch welchen von einem stromaufwärtigen hinteren Vorrichtungsteil 15, welches vom Körper 4 getragen wird, Pulver pneumatisch zur Düse 10 und durch eine in der Düse 10 gebildete Sprühöffnung 18 gefördert wird. Das Pulver wird durch die Sprühöffnung 18 auf einen zu beschichtenden Gegenstand gesprüht. Das Zwischenstück 12 erstreckt sich in Form einer schmalen Platte durch den Pulverkanal 14, so daß das Pulver am Zwischenstück 12 axial vorbeiströmen kann. Das Zwischenstück 12 trägt eine nadelförmige Aufladungselektrode 20, deren Elektrodenspitze 21 kurz stromaufwärts der Sprühöffnung 18 aus einem im Zwischenstück 12 gebildeten Luftkanal 24 herausragt. Dem Luftkanal 24 zugeführte Druckluft strömt an der Elektrodenspitze 21 vorbei in den Pulverkanal 14 und in die Sprühöffnung 18. Die Aufladungselektrode 20 ist axial mit Bezug auf den Pulverkanal 14 angeordnet und ihr stromaufwärtiges hinteres Ende ist über mindestens einen elektrischen Widerstand 26 sowie eine sich stromaufwärts daran anschließende elektrische Steckverbindung 28 und 29 an einen vorderen Hochspannungsausgang 30 eines Hochspannungserzeugers 32 angeschlossen. Der Hochspannungserzeuger 32 ist vorzugsweise eine bekannte Kaskadenschaltung aus elektrischen Widerständen und elektrischen Kondensatoren. Hochspannungserzeuger dieser Art sind beispielsweise aus der US-PS 4 196 465 bekannt. Der Hochspannungserzeuger 32 weist einen hinteren Niederspannungseingang 34 zum Anschluß an eine externe elektrische Niederspannungsquelle auf. Der Hochspannungserzeuger 32 ist in einem im Körper 4 gebildeten Hohlraum 36 untergebracht, welcher sich parallel zum Pulverkanal 14 erstreckt und in einer stromabwärtigen Stirnfläche 48 des Körpers 4 mündet. Durch axiales Herausziehen des Zwischenstückes 12 wird die Steckverbindung 28 und 29 getrennt. Der Hohlraum 36 ist zum Zwischenstück 12 hin offen, so daß nach Trennung der elektrischen Steckverbindung 28, 29 der Hochspannungserzeuger 32 aus dem Hohlraum 36 herausgezogen und gegen einen anderen Hochspannungserzeuger ausgetauscht werden kann. Die vom Hochspannungserzeuger 32 erzeugte elektrische Hochspannung bewirkt über die Elektrode 20 und durch die an ihr vorbeiströmende Luft des Luftkanals 24 eine elektrostatische Aufladung des Pulvers.The electrostatic shown in the drawings Powder spray device contains a body 4 electrically insulating material, one axially through it through pipe 8 made of electrically insulating Material, a downstream of the body 4 and that Tube 8 connecting intermediate piece 12 and one itself downstream nozzle 10 each electrically insulating material. The tube 8 that Intermediate piece 12, a bushing 6 surrounding it and the nozzle 10 form a powder channel 14 through which one upstream rear device part 15, which is carried by the body 4, powder pneumatically to the nozzle 10 and through a spray opening formed in the nozzle 10 18 is promoted. The powder comes through the spray opening 18 sprayed onto an object to be coated. The Intermediate piece 12 extends in the form of a narrow Plate through the powder channel 14 so that the powder on Intermediate piece 12 can flow axially past. The Intermediate piece 12 carries an acicular Charging electrode 20, the electrode tip 21 short upstream of the spray opening 18 from an in Intermediate piece 12 formed air channel 24 protrudes. The Air duct 24 supplied compressed air flows on the Electrode tip 21 over into the powder channel 14 and in the spray opening 18. The charging electrode 20 is axial arranged with respect to the powder channel 14 and her upstream aft end is over at least one electrical resistance 26 and one upstream adjoining electrical plug connection 28 and 29 to a front high voltage output 30 of a high voltage generator 32 connected. The high voltage generator 32 is preferably a known cascade connection from electrical resistors and electrical capacitors. High voltage generators of this type are, for example known from US-PS 4 196 465. The high voltage generator 32 has a rear low voltage input 34 for connection to an external electrical low voltage source on. The high voltage generator 32 is in a cavity 36 formed in the body 4, which extends parallel to the powder channel 14 and in a downstream end face 48 of the body 4 flows. By axially pulling out the intermediate piece 12 the connector 28 and 29 is disconnected. The cavity 36 is open to the intermediate piece 12, so that after Separation of the electrical connector 28, 29 of the High voltage generator 32 pulled out of the cavity 36 and against another high voltage generator can be exchanged. The high voltage generator 32 generated high voltage electrical causes Electrode 20 and by the air flowing past it the air duct 24 an electrostatic charge of the Powder.

Der Körper 4 ist mit einem Außengewinde 40 versehen, auf welches eine Hülse 42 aus elektrisch isolierendem Material mit ihrem Innengewinde 41 geschraubt ist. Die Hülse 42 ist über die Düse 10 gesteckt und drückt mit einer nach hinten zeigenden radialen Stirnfläche 44 gegen eine nach vorne zeigende radiale Stirnfläche 46 der Düse 10. Dadurch spannt die Hülse 42 mit ihrer radialen Stirnfläche 44 die Düse 10 und das Zwischenstück 12 gegen die nach vorne weisende radiale Stirnfläche 48 des Körpers 4. Zum Herausnehmen der Düse 10, des Zwischenstücks 12 und des Hochspannungserzeugers 32 braucht somit lediglich die Hülse 42 vom Körper 4 abgeschraubt zu werden. The body 4 is provided with an external thread 40 which is a sleeve 42 made of electrically insulating Material is screwed with its internal thread 41. The Sleeve 42 is placed over the nozzle 10 and presses with against a rearward facing radial end face 44 a forwardly facing radial face 46 of the nozzle 10. As a result, the sleeve 42 tensions with its radial end face 44 the nozzle 10 and the intermediate piece 12 against the forward-facing radial face 48 of body 4. To remove the nozzle 10, the intermediate piece 12 and of the high voltage generator 32 thus only needs that Sleeve 42 to be unscrewed from the body 4.

Die Hülse 42 ist über ihr Innengewinde 41 hinaus nach hinten durch einen Hülsenabschnitt 50 verlängert. Dieser mit Bezug auf das Gewinde 41 hintere Hülsenabschnitt 50 trägt eine Vielzahl von ringförmig um den Pulverkanal 14 herum angeordneten nadelförmigen Gegenelektroden 52. Die Gegenelektroden 52 befinden sich innerhalb von radialen Bohrungen 56, die im Hülsenabschnitt 50 gebildet sind und in seiner äußeren Mantelfläche 58 münden. Die Bohrungen 56 können über einen sie verbindenden Ringkanal 57 in der Hülse 42 an eine Druckluftquelle angeschlossen sein, deren Druckluft über die Gegenelektroden 52 strömt und dadurch Pulver und Staub von den Gegenelektroden 52 abhält. Ein elektrischer Leitungsweg 60 erstreckt sich von einem elektrischen Anschlußelement 62 auf der Rückseite des hinteren Vorrichtungsteils 15 im wesentlichen parallel zum Pulverkanal 14 bis zu den radial inneren Enden der Gegenelektroden 52, so daß die Gegenelektroden 52 über das Anschlußelement 62 an ein elektrisches Potential, vorzugsweise Erdpotential, angeschlossen werden können. Dieses elektrische Potential unterscheidet sich derart vom elektrischen Hochspannungspotential der Aufladungselektrode 20, daß die Gegenelektroden 52 freie Ionen aus dem Strom von zerstäubtem Pulver stromabwärts der Sprühöffnung 18 anziehen, welche dann über den Leitungsweg 60 und das Anschlußelement 62 neutralisiert werden. Die Gegenelektroden 52 befinden sich möglichst nahe bei der Sprühöffnung 18, um den besten elektrischen Wirkungsgrad zu haben. In der Praxis sind jedoch die Gegenelektroden 52 entsprechend Fig. 1 der Zeichnungen stromaufwärts der Sprühöffnung 18 konzentrisch um den Pulverkanal 14 herum außerhalb von ihm angeordnet und stromaufwärts mit Bezug auf die Sprühöffnung 18 so weit zurückgesetzt, daß zwar eine ausreichende Anzahl freier Ionen aus dem zerstäubten Pulverstrom abgesaugt wird, sich jedoch keine Pulverpartikel an den Gegenelektroden 52 ablagern können und kein elektrischer Überschlag von der Aufladungselektrode 20 zu den Gegenelektroden 52 stattfinden kann. Anstelle einer Vielzahl könnte auch nur eine einzige Gegenelektrode 52 verwendet werden; dann vorzugsweise in Form eines Ringes koaxial zur Hülse 42. In nochmals anderer Ausführungsform kann die Hülse 42 aus elektrisch leitendem Material bestehen und selbst die Gegenelektrode bilden.The sleeve 42 is beyond its internal thread 41 extended at the rear by a sleeve section 50. This with respect to the thread 41 rear sleeve portion 50 carries a plurality of rings around the powder channel 14 needle-shaped counter electrodes 52 arranged around it Counter electrodes 52 are located within radial Bores 56 formed in the sleeve portion 50 and open into its outer surface 58. The holes 56 can be connected in the Sleeve 42 to be connected to a compressed air source, whose compressed air flows over the counter electrodes 52 and thereby powder and dust from the counter electrodes 52 holds. An electrical conduction path 60 extends from an electrical connection element 62 on the Back of the rear device part 15 in essentially parallel to the powder channel 14 to the radially inner ends of the counter electrodes 52 so that the Counter electrodes 52 via the connecting element 62 to electrical potential, preferably earth potential, can be connected. This electrical potential differs in this way from the electrical high-voltage potential the charging electrode 20 that the Counter electrodes 52 free ions from the stream of sputtered Powder downstream of spray opening 18 tighten, which then via conduit 60 and that Connection element 62 are neutralized. The counter electrodes 52 are as close as possible to the spray opening 18 to the best electrical efficiency to have. In practice, however, the counter electrodes are 52 corresponding to Fig. 1 of the drawings upstream of the Spray opening 18 concentrically around the powder channel 14 located outside of it and related upstream reset to the spray opening 18 so far that a sufficient number of free ions from the atomized Powder stream is sucked off, but none Can deposit powder particles on the counter electrodes 52 and no electrical flashover from the Charging electrode 20 to the counter electrodes 52 can take place. Instead of a multitude it could just be a single counter electrode 52 may be used; then preferably in the form of a ring coaxial with the sleeve 42. In yet another embodiment, the sleeve 42 can be made of exist electrically conductive material and even the Form counter electrode.

Der elektrische Leitungsweg 60 ist auf einen mit Bezug auf die Strömungsrichtung des Pulvers im Pulverkanal 14 stromaufwärtigen hinteren Leitungsabschnitt 64 und einen stromabwärtigen vorderen Leitungsabschnitt 66 aufgeteilt. Die beiden Leitungsabschnitte 64 und 66 sind durch eine Ringkontaktverbindung 68 miteinander verbunden. Die Ringkontaktverbindung 68 besteht im wesentlichen aus einem Kontaktring 70 aus elektrisch leitendem Material und einer Kontaktiervorrichtung 72. Die Kontaktiervorrichtung 72 liegt an dem Kontaktring 70 an und ist mit dem hinteren Leitungsabschnitt 64 elektrisch verbunden. Der Kontaktring 70 ist in der Innenumfangsfläche 74 nahe des hinteren Endes des hinteren Hülsenabschnittes 50 untergebracht und befestigt und mit dem vorderen Leitungsabschnitt 66 elektrisch verbunden. Dieser vordere Leitungsabschnitt 66 erstreckt sich achsparallel zum Pulverkanal 14 zwischen den beiden aneinander angrenzenden Mantelflächen 78 und 79 von zwei konzentrisch zueinander angeordneten und miteinander drehfest verbundenen Rohren 80 und 81, welche zusammen den hinteren Hülsenabschnitt 50 bilden. Beim Aufschrauben und Abschrauben der Hülse 42 dreht sich der Kontaktring 70 zusammen mit der Hülse 42 konzentrisch um den Pulverkanal 14 relativ zur Kontaktiervorrichtung 72. Die Kontaktiervorrichtung 72 sitzt in einer in der Außenfläche des Körpers 4 gebildeten Ausnehmung 84 auf dem Mündungsrand einer Bohrung 63 und ist durch einen Stab aus elektrisch leitendem Material elektrisch verbunden, welcher den hinteren Leitungsabschnitt 64 bildet. Der Stab 64 erstreckt sich durch die Bohrung 63 und ist mit dem Anschlußelement 62 elektrisch verbunden. Der Stab 64 und das Anschlußelement 62 bilden eine Steckverbindung. Die Bohrung 63 ist im Körper 4 gebildet und verläuft parallel zum Pulverkanal 14. Die undrehbare Kontaktiervorrichtung 72 ist am Körper 4 ortsfest angeordnet und liegt von innen nach außen am Kontaktring 70 an. Der Stab 64 in der Bohrung 63 verhindert ein Drehen der Kontaktiervorrichtung 72 um den Pulverkanal 14. Der Kontaktring 70 und der Hülsenabschnitt 50 übergreifen die undrehbare Kontaktiervorrichtung 72. Obwohl die Kontaktiervorrichtung 72 nicht um den Pulverkanal 14 drehbar ist, sondern ortsfest angeordnet ist, hat sie bei jeder Drehposition der Hülse 42 mit dem Kontaktring 70 mechanischen und elektrischen Kontakt, da sich der Kontaktring 70 um den gesamten Innenumfang der Hülse 42 erstreckt.The electrical conduction path 60 is related to one on the flow direction of the powder in the powder channel 14 upstream rear conduit section 64 and one divided downstream front pipe section 66. The two line sections 64 and 66 are by a Ring contact connection 68 interconnected. The ring contact connection 68 consists essentially of one Contact ring 70 made of electrically conductive material and a contacting device 72. The contacting device 72 lies against the contact ring 70 and is with the rear line section 64 electrically connected. Of the Contact ring 70 is in the inner peripheral surface 74 near the rear end of the rear sleeve portion 50 housed and fastened and with the front pipe section 66 electrically connected. This front one Line section 66 extends axially parallel to Powder channel 14 between the two adjacent Shell surfaces 78 and 79 of two concentric to each other arranged and non-rotatably connected Pipes 80 and 81, which together form the rear Form sleeve section 50. When screwing on and Unscrewing the sleeve 42 rotates the contact ring 70 together with the sleeve 42 concentrically around the powder channel 14 relative to the contacting device 72. Die Contacting device 72 sits in one in the Recess 84 formed on the outer surface of the body 4 the mouth of a bore 63 and is through a Rod made of electrically conductive material connected to the rear pipe section 64 forms. The rod 64 extends through the bore 63 and is electrically connected to the connection element 62. The rod 64 and the connecting element 62 form one Connector. The bore 63 is formed in the body 4 and runs parallel to the powder channel 14. The non-rotatable Contacting device 72 is stationary on the body 4 arranged and lies from the inside to the outside of the contact ring 70 on. The rod 64 in the bore 63 prevents Rotating the contacting device 72 around the powder channel 14. The contact ring 70 and the sleeve section 50 overlap the non-rotatable contacting device 72. Although the contact device 72 is not the Powder channel 14 is rotatable, but arranged stationary is, it has at each rotational position of the sleeve 42 with the Contact ring 70 mechanical and electrical contact, there the contact ring 70 around the entire inner circumference of the Sleeve 42 extends.

Durch Abschrauben der Hülse 42 vom Körper 4 wird die Kontaktiervorrichtung 72 freigelegt und kann dann zusammen mit dem Stab 64 aus dem Körper 4 nach vorne herausgezogen werden. Durch diese Herausnahme der Kontaktiervorrichtung 72 und des Stabes 64, welcher den hinteren Leitungsabschnitt bildet, wird sichergestellt, daß kein elektrischer Überschlag von der Aufladungselektrode 20 zu einem elektrisch leitenden Zuleitungselement 72, 64 der Gegenelektroden 52 stattfinden kann, wenn die Pulversprühvorrichtung ohne die Gegenelektroden 52 verwendet wird. Ohne die Gegenelektrode 52 muß darauf geachtet werden, daß Elemente, wie beispielsweise die Kontaktiervorrichtung 72 und der Stab 64, welche ein anderes elektrisches Potential als die Aufladungselektrode 20 haben, so weit von der Aufladungselektrode 20 entfernt sind, daß die Hochspannung der Aufladungselektrode 20 nicht auf diese Elemente 72 und 64 überspringen kann. Am sichersten und einfachsten ist es, die Kontaktiervorrichtung 72 und den Stab 64 aus der Pulversprühvorrichtung herauszunehmen.By unscrewing the sleeve 42 from the body 4 Contacting device 72 exposed and can then together with the rod 64 from the body 4 to the front be pulled out. By removing the Contacting device 72 and the rod 64, which the forms the rear line section, ensures that no electrical flashover from the Charging electrode 20 to an electrically conductive Lead element 72, 64 of the counter electrodes 52 take place can if the powder spray device without the Counter electrodes 52 is used. Without that Counterelectrode 52 must be ensured that Elements, such as the contacting device 72 and rod 64, which is another electrical Have potential as the charging electrode 20 so far are removed from the charging electrode 20 that the High voltage of the charging electrode 20 is not on this Can skip items 72 and 64. Safest and the simplest is the contacting device 72 and the Take rod 64 out of the powder spray device.

In der äußeren Ausnehmung 84 des Körpers 4 ist ein Axialanschlag 86 gebildet, hinter welchen die Kontaktiervorrichtung 72 um die Längsachse des Stabes 64 geschwenkt ist und hinter welchem sie von der Hülse 42 gehalten wird. Dadurch wird die Kontaktiervorrichtung 72 vom Mündungsrand der Bohrung 63 und dem Axialanschlag 86 in einer bestimmten axialen Position gegenüber dem Kontaktring 70 gehalten. Wenn die Hülse 42 vom Körper 4 abgeschraubt wird, kann die Kontaktiervorrichtung 72 um die Längsachse der Stabes 64 über den Axialanschlag 86 hinausgeschwenkt werden und anschließend zusammen mit dem Stab 64 axial aus dem Körper 4 herausgezogen werden. In the outer recess 84 of the body 4 is a Axial stop 86 formed, behind which the Contacting device 72 about the longitudinal axis of the rod 64 is pivoted and behind which it from the sleeve 42nd is held. This makes the contacting device 72 from the mouth of the bore 63 and the axial stop 86 in a certain axial position relative to the Contact ring 70 held. When the sleeve 42 from the body 4th is unscrewed, the contacting device 72 um the longitudinal axis of the rod 64 via the axial stop 86 be swung out and then together with the rod 64 are pulled axially out of the body 4.

Fig. 2 zeigt die Kontaktiervorrichtung 72 und den Stab 64 in Richtung eines Pfeiles II in Fig. 1 gesehen hinter dem Axialanschlag 86 in einer verriegelten Betriebsposition. Fig. 3 zeigt die Kontaktiervorrichtung 72 von Fig. 2 in einer entriegelten Entnahmeposition, in welche sie nach Abnahme der Hülse 42 in Richtung eines in Fig. 2 gezeigten Pfeiles 88 um die Längsachse des Stabes 64 über die Höhe des Axialanschlages 86 hinaus geschwenkt wurde. Von der entriegelten Entnahmeposition von Fig. 3 kann die Kontaktiervorrichtung 72 zusammen mit dem Stab 64 über den Axialanschlag 86 hinweg parallel zum Pulverkanal 14 aus dem Körper 4 nach vorne herausgezogen werden.2 shows the contacting device 72 and the rod 64 seen in the direction of an arrow II in Fig. 1 behind the Axial stop 86 in a locked operating position. FIG. 3 shows the contacting device 72 from FIG. 2 in an unlocked removal position, in which it is after Removal of the sleeve 42 in the direction of one in FIG. 2 arrow 88 shown about the longitudinal axis of the rod 64 the height of the axial stop 86 was pivoted out. From the unlocked removal position of Fig. 3, the Contacting device 72 together with the rod 64 the axial stop 86 parallel to the powder channel 14 are pulled out of the body 4 to the front.

Die relativ zum Kontaktring 70 undrehbar angeordnete Kontaktiervorrichtung 72 besteht aus einem Kontaktgehäuse 90 aus elektrisch leitendem Material, einer den Kontaktring 70 kontaktierenden Kugel 91 aus elektrisch leitendem Material, einer in das Kontaktgehäuse 90 geschraubten Schraube 92 und einer Feder 93 je aus elektrisch leitendem Material. Die Feder 93 ist zwischen die Schraube 92 und die Kontaktkugel 91 eingespannt und drückt die Kontaktkugel 91 elastisch gegen den Kontaktring 70. Der den hinteren Leitungsabschnitt 64 bildende Stab aus elektrisch leitendem Material ist mit dem Kontaktgehäuse 90 mechanisch verbunden und damit mit der Kontaktkugel 91 elektrisch leitend verbunden.The non-rotatably arranged relative to the contact ring 70 Contacting device 72 consists of a contact housing 90 made of electrically conductive material, one of the Contact ring 70 contacting ball 91 made of electrical conductive material, one screwed into the contact housing 90 Screw 92 and a spring 93 each electrically conductive material. The spring 93 is between the screw 92 and the contact ball 91 clamped and presses the contact ball 91 elastically against the Contact ring 70. The rear line section 64 forming rod made of electrically conductive material is with the contact housing 90 mechanically connected and thus with the contact ball 91 electrically connected.

Die Düse 10 kann auf einfache Weise durch Abnahme der Hülse 42 gegen eine andere Düse ausgetauscht werden, welche eine im Querschnitt kreisrunde oder schlitzförmige Sprühöffnung 18 haben kann. The nozzle 10 can be easily removed by removing the Sleeve 42 can be exchanged for another nozzle, which is circular or slit-shaped in cross section Can have spray opening 18.

Für die Verwendung der Pulversprühvorrichtung ohne die Gegenelektroden 52 wird vorzugsweise die Hülse 42, welche die Gegenelektroden 52 trägt, gegen eine andere Hülse 142 ausgetauscht, welche entsprechend Fig. 5 keine Gegenelektroden 52 hat.For using the powder sprayer without the Counter electrodes 52 are preferably the sleeve 42, which counter electrodes 52 against another sleeve 142 exchanged, which according to FIG. 5 no counter electrodes 52 has.

Damit hierbei nicht vergessen werden kann, die Kontaktiervorrichtung 72 und den hinteren Leitungsabschnitt 64 in Form des Stabes zu entfernen, bevor die andere, keine Gegenelektroden 52 aufweisende Hülse 142 benutzt wird, sind gemäß der Erfindung Mittel vorgesehen, welche sicherstellen, daß diese andere Hülse 142 nur dann an der Pulversprühvorrichtung befestigt werden kann, wenn vorher die Kontaktiervorrichtung 72 und der hintere Leitungsabschnitt 64 entfernt wurden. Diese Mittel können darin bestehen, daß die mit einer oder mehreren Gegenelektroden 52 versehene eine Hülse 42 entsprechend Fig. 4 an ihrem hinteren Endabschnitt 146 mit einem vergrößerten Innendurchmesser 147 versehen wird, welcher größer ist als der Innendurchmesser 150 des hinteren Endabschnittes einer in Fig. 5 gezeigten Hülse 142, welche keine Gegenelektroden 52 hat. Der Kontaktring 70 befindet sich im Endabschnitt 146 auf dem vergrößerten Innendurchmesser 147 und die Kontaktiervorrichtung 72 erstreckt sich in den Endabschnitt 146 bis zum Kontaktring 70. Dadurch kann die andere Hülse 142 von Fig. 5 nicht über die Kontaktiervorrichtung 72 geschoben werden. Die andere Hülse 142 kann am Körper 4 nur dann richtig befestigt werden, wenn vorher die Kontaktiervorrichtung 72 und der Stab 64 aus der Pulversprühvorrichtung herausgenommen werden.So that it cannot be forgotten that Contact device 72 and the rear line section 64 in the form of the rod before removing the other sleeve 142 having no counter electrodes 52 means are used according to the invention, which ensure that this other sleeve 142 only can then be attached to the powder spray device, if previously the contact device 72 and the rear Line section 64 were removed. These funds can consist in that with one or more Counter electrodes 52 provided a sleeve 42 accordingly Fig. 4 at its rear end portion 146 with a enlarged inner diameter 147 is provided, which is larger than the inner diameter 150 of the rear 5 of a sleeve 142 shown in FIG. 5, which has no counter electrodes 52. The contact ring 70 is located in the end section 146 on the enlarged Inner diameter 147 and the contacting device 72 extends into end portion 146 to Contact ring 70. This allows the other sleeve 142 of 5 is not pushed over the contacting device 72 will. The other sleeve 142 can only on the body 4 properly attached if the Contacting device 72 and the rod 64 from the Powder spray device can be removed.

Claims (10)

  1. An electrostatic powder spray apparatus including a body (4); a powder duct (14) for pneumatically conveyed powder, which extends through the body (4); a spray opening (18) at the downstream end of the powder duct (14) for spraying the powder on to an article to be coated; at least one charging electrode (20) for electrostatically charging the powder with electrical high voltage in the proximity of the spray opening (18); at least one counter-electrode (52) which is arranged at a spacing from the charging electrode (20) radially outside the flow of powder; an electrical conduction path (60) which extends from an electrical connecting element (62) at a rear location on the body (4) which is upstream with respect to the powder flow direction to the counter-electrode (52) and which can be connected to an electrical potential by which the counter-electrode (52) removes free ions from the flow of the sprayed powder by electrostatic forces; the electrical conduction path (60) is divided into a rear conduction portion (64) electrically connected to the electrical connecting element (62) and a front conduction portion (66) electrically connected to the counter-electrode (52); a sleeve (42) which can be fitted on to the body (4) from the spray opening (18) and which can be removed and which is provided with the counter-electrode (52) and the front conduction portion (66); rotary connecting means (40, 41) on the body (4) and on the sleeve (42), by which the sleeve (42) can be fixed to the body (4) by a rotary movement and can be released from the body (4) again by another rotary movement, wherein the rear conduction portion (64) and a non-rotatable contact portion (72) electrically connected thereto are removably disposed in the body (40) but the sleeve (42) beside the non-rotatable contact portion (72) blocks removal as long as the sleeve is fixed to the body (4); characterised in that the two conduction portions (64, 66) are releasably electrically connected together by way of a ring contact device (68) which has the non-rotatable contact portion (72) and a contact ring (70) which contacts it and which surrounds the powder duct (14) at a radial spacing and which is arranged rotatably around the powder duct (14) relative to the non-rotatable contact portion (72) and which is electrically connected to the front conduction portion (66), and that the sleeve (42) is provided with the contact ring (70).
  2. An electrostatic powder spray apparatus according to claim 1 characterised in that there is provided a nozzle (10) forming the spray opening (18) and that the sleeve (42) engages over the nozzle (10) and holds it axially in a predetermined position between itself and the body (4).
  3. An electrostatic powder spray apparatus according to one of the preceding claims characterised in that the sleeve (42) comprises at least two tubes (80, 81) which are arranged coaxially one within the other and which are non-rotatably connected to each other, and that between the two tubes (80, 81) the front conduction portion (66) extends from the rotatable contact ring (70) of the ring contact device (68) to the counter-electrode (52).
  4. An electrostatic powder spray apparatus according to one of the preceding claims characterised in that the sleeve (42) is provided with a female screwthread (41) and is thus screwed on to a male screwthread (40) on the body (4).
  5. An electrostatic powder spray apparatus according to one of the preceding claims characterised in that the non-rotatable contact portion (72) of the ring contact device (68) is pivotable about a longitudinal axis of the rear conduction portion (64) behind an axial abutment (86) of the body (4) into an operative position and in the opposite pivotal direction away from the axial abutment (86) into a removal position in which the non-rotatable contact portion (72) and the rear conduction portion (64) can be removed from the body (4) beyond the axial abutment (86), and that the sleeve (42) engages over the non-rotatable contact portion (72) and thereby holds it in its operative position so that for pivotal movement of the non-rotatable contact portion (72) into its removal position the sleeve (42) must first be moved away from the non-rotatable contact portion (72).
  6. An electrostatic powder spray apparatus according to one of the preceding claims characterised in that the ring contact device (68) is arranged so far away from the charging electrode (20) in the rearward direction that no electrical high-voltage flash-over can occur from the charging electrode (20) to the non-rotatable contact portion (72) or the rear conduction portion (64) even when the powder spray apparatus is used without the sleeve (42) and thus without the counter-electrode (52) and without the front conduction portion (66).
  7. An electrostatic powder spray apparatus according to one of the preceding claims characterised in that formed in the body (4) is a cavity (36) into which a high-voltage generating means (32) for generating the high voltage of the charging electrode (20) is fitted interchangeably for another high-voltage generating means, that the cavity (36) is open in a forwardly facing end surface (48), and that the high-voltage generating means (32) is held axially in the cavity (36) by the sleeve (42) and the sleeve (42) first has to be removed for the interchange operation.
  8. An electrostatic powder spray apparatus according to one of the preceding claims characterised in that the body (4) and/or the sleeve (42) comprise electrically insulating material.
  9. An electrostatic powder spray apparatus according to one of the preceding claims characterised in that there is provided a second sleeve (142) which is interchangeable for the first sleeve (42), that the two sleeves (42; 142) are of different configurations such that the second sleeve (142) can be fixed to the body (4) only when in addition to the one sleeve (42) the non-rotatable contact portion (72) and the rear conduction portion (64) are also removed from the powder spray apparatus.
  10. An electrostatic powder spray apparatus according to claim 9 characterised in that the second sleeve (142) comprises electrically insulating material.
EP94110270A 1993-08-02 1994-07-01 Device for the electrostatic spraying of powdery products Expired - Lifetime EP0637466B1 (en)

Applications Claiming Priority (2)

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DE4325911 1993-08-02
DE4325911A DE4325911A1 (en) 1993-08-02 1993-08-02 Electrostatic powder spraying device

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EP0637466B1 true EP0637466B1 (en) 1998-04-01

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CN102357436B (en) * 2011-08-08 2013-06-05 顾星 Electrostatic atomizer
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FR2297675A1 (en) * 1975-01-16 1976-08-13 Air Ind FLAT JET ELECTROSTATIC POWDERING PROCESS AND DEVICE
HU173207B (en) * 1976-11-10 1979-03-28 Hajtomuevek Es Festoekeszuelek Rotary head paint sprayer with multi-layer electrode
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DE9305642U1 (en) * 1993-04-15 1993-06-17 Itw Gema Ag, St. Gallen Electrostatic spray device

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EP0637466A1 (en) 1995-02-08
DE4325911A1 (en) 1995-02-09
ATE164535T1 (en) 1998-04-15
CN1105608A (en) 1995-07-26
DE59405564D1 (en) 1998-05-07

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