EP0941145B1 - Powder spraying device - Google Patents

Powder spraying device Download PDF

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Publication number
EP0941145B1
EP0941145B1 EP96942367A EP96942367A EP0941145B1 EP 0941145 B1 EP0941145 B1 EP 0941145B1 EP 96942367 A EP96942367 A EP 96942367A EP 96942367 A EP96942367 A EP 96942367A EP 0941145 B1 EP0941145 B1 EP 0941145B1
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EP
European Patent Office
Prior art keywords
powder
chamber
electrode
spraying
electrodes
Prior art date
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EP96942367A
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German (de)
French (fr)
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EP0941145A1 (en
Inventor
Günter BÖRNER
Hans-Christoph Nienburg
Josef Wittmann
Helmut BÖHME
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ABB Research Ltd Switzerland
ABB Research Ltd Sweden
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ABB Research Ltd Switzerland
ABB Research Ltd Sweden
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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
    • B05B5/03—Discharge apparatus, e.g. electrostatic spray guns characterised by the use of gas, e.g. electrostatically assisted pneumatic spraying
    • B05B5/032—Discharge apparatus, e.g. electrostatic spray guns characterised by the use of gas, e.g. electrostatically assisted pneumatic spraying for spraying particulate materials

Definitions

  • the invention relates to a powder spraying device for electrostatic powder coating according to the preamble of claim 1.
  • a powder spray device at least contains a chamber in which a tip discharge electrode opposite the material flow and an opposite like this polarized blunt counter electrode are arranged upstream at a distance from the tip discharge electrode.
  • a configuration with several is used to improve the charging of the powder particles chambers connected in series. It is also proposed that To design the chamber in such a way that there are continuous enlargements and narrowing which are intended to cause material particles to brake under turbulence and so more intensely exposed to the force field. Finally, it is suggested to arrange openings distributed over the circumference of the at least one chamber, via the additional air is introduced, which is the average density of the mixture of air and Reduce powder and improve charging.
  • a powder spraying device according to the preamble of claim 1 is known from EP-A-237 249 known.
  • the device has a chamber, the cross section of which is larger than the cross section of a feed line for a powder-air mixture.
  • a ground electrode and several high voltage electrodes arranged with cleaning air are inflatable.
  • the design of the chamber and in particular the electrodes is chosen so that a Plasma with positive polarity and a plasma with negative polarity are formed.
  • To the A voltage is intermittently applied to plasma electrodes. Trials have shown that these measures cause sparking and contamination of the electrodes.
  • the invention is therefore based on the object of specifying a powder spraying device, which leads to an improved charging of the powder particles and thereby to a lead to an improved deposition rate.
  • An embodiment refers to the arrangement of one or more external electrodes further improvement of charging or for field control and thus to increase of efficiency.
  • Another embodiment relates to a variable design of the distance between earth electrode and high voltage electrodes, which is an optimum between good charging and disruptive effects such as re-ionization.
  • Chamber 1 shows a powder spraying device 10.
  • a swirl chamber 1 is placed on a carrier element 6 of the powder spraying device 10.
  • Chamber 1 is in the Embodiment preferably cylindrical.
  • one Cross-section can also be an ellipsoidal or polygonal cross-section It is essential that the cross section of the chamber is larger than the cross section a supply line 11 for powder and air PL.
  • the powder / air supply line 11 opens transverse to the main axis 12 of the chamber 1 into the chamber 1.
  • the powder / air mixture PL in the spray direction 13, against the spray direction 13 (Fig. 3) or be introduced transversely to the spray direction 13.
  • the spray direction 13 is the main axis 12 towards an outlet 3.
  • the powder is charged by corona, which is attached to needle-shaped high-voltage electrodes 7 is generated, which are at high voltage potential.
  • the high tension is generated using a high-voltage cascade 4, which is part of the powder spraying device 10, and via an electrical connection 22 to the high voltage needles delivered.
  • the high-voltage electrodes 7 are arranged in a ring in the area of the outlet 3 and form an intensive corona to the earth electrode 5.
  • all powder particles are forced through to move an area with high field strength and charge density.
  • additional electrodes 8 that can be arranged can be intensified via external charging.
  • On outer impact body 9 produces a more or less wide rotationally symmetrical Powder cloud.
  • a slit-shaped flat nozzle 23 can also be used kick that creates a flat powder jet.
  • FIG. 2 Such an alternative design of the outlet area is shown in FIG. 2.
  • the other design of the powder spraying device corresponds to that of FIG. 1 which will be further described below.
  • the needle-shaped high-voltage electrodes 7 are ring-shaped in a front ring 2 arranged around the circumference.
  • the outlet 3 is placed on the front ring 2.
  • the chamber 1 is made of an insulating material such as plastic, glass or ceramic
  • the earth electrode 5 is tubular and in the carrier element 6 in the direction of Main axis 12 arranged centered.
  • the tubular earth electrode 5 preferably has a diameter of 0.3 cm inside and 0.5 cm outside.
  • On the inside of the chamber directed end of the earth electrode 5 is this by a with rounded edges 17th provided headboard 20 completed.
  • the earth electrode 5 and in particular its Headboard 20 is covered with a cover 16 made of insulating material to electrical Avoid breakthroughs.
  • the insulating cover 16 has one on the front Cover opening 18 approximately 0.1 to 0.5 cm in diameter.
  • earth electrode cleaning air RLE is guided, which is a powder particle accumulation avoids at the earth electrode 5.
  • the cleaning air also ensures RLE for an additional swirl of the powder and it can be changed the air rate, the powder / air ratio is adjusted or regulated.
  • the tubular earth electrode 5 has 20 openings in an area in front of the head part 19, through which the cleaning air RLE out of the pipe into a gap 21 between kick the earth electrode 5 and the cover 16, wash around the head part 20 and can emerge from the cover opening 18 into the chamber 1.
  • the supplied for cleaning the earth electrode 5 and the high-voltage electrodes 7 Cleaning air RLE, RLH can be used to advantage after switching off the supply of the powder / air mixture PL powder particles from the chamber 1 blow out and a deposit of the powder particles on the electrodes 5, 7 to avoid
  • Fig. 3 shows a basic illustration of a powder spraying device, in which - how further already mentioned above - the powder / air mixture PL via the feed line 11 is initiated against the spray direction.
  • FIG. 3 Baffle plate 24 shown, the powder particles closer to the high voltage needles 7 introduces. The powder then exits through holes 25 and strikes the outer baffle plate 9. It is understood that the other, described with reference to FIG. 1 Refinements also apply to the embodiment according to FIG. 3.

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  • Electrostatic Spraying Apparatus (AREA)

Description

Die Erfindung bezieht sich auf eine Pulversprüheinrichtung zur elektrostatischen Pulverbeschichtung nach dem Oberbegriff des Anspruchs 1.The invention relates to a powder spraying device for electrostatic powder coating according to the preamble of claim 1.

Aus der DE 27 22 100 C2 ist eine Pulversprüheinrichtung bekannt, die wenigstens eine Kammer enthält, in der eine der Materialströmung entgegengesetzte Spitzenentladungselektrode und eine entgegengesetzt wie diese gepolte stumpfe Gegenelektrode stromauf im Abstand von der Spitzenentladungselektrode angeordnet sind. Zur Verbesserung der Aufladung der Pulverteilchen ist eine Ausgestaltung mit mehreren hintereinandergeschalteten Kammern vorgesehen. Außerdem wird vorgeschlagen, die Kammer so zu gestalten, daß sich kontinuierlich Erweiterungen und Verengungen ergeben, die bewirken sollen, daß sich Materialteilchen unter Verwirbelung abbremsen und so intensiver dem Kraftfeld ausgesetzt werden. Schließlich wird vorgeschlagen, über den Umfang der wenigstens einen Kammer verteilt Öffnungen anzuordnen, über die Zusatzluft eingeleitet wird, die die mittlere Dichte des Gemisches aus Luft und Pulver verringern und die Aufladung verbessern.From DE 27 22 100 C2 a powder spray device is known, at least contains a chamber in which a tip discharge electrode opposite the material flow and an opposite like this polarized blunt counter electrode are arranged upstream at a distance from the tip discharge electrode. to A configuration with several is used to improve the charging of the powder particles chambers connected in series. It is also proposed that To design the chamber in such a way that there are continuous enlargements and narrowing which are intended to cause material particles to brake under turbulence and so more intensely exposed to the force field. Finally, it is suggested to arrange openings distributed over the circumference of the at least one chamber, via the additional air is introduced, which is the average density of the mixture of air and Reduce powder and improve charging.

Versuche haben gezeigt, daß die Maßnahmen nicht ausreichen, um eine Pulverbeschichtung mit zufriedenstellendem Wirkungsgrad auf einem Werkstück zu bewirken. Da die Elektroden direkt mit dem Pulver in Berührung sind, kommt es zu Pulverablagerungen auf den Elektroden, was eine deutlich schlechtere Aufladung zur Folge hat.Tests have shown that the measures are not sufficient to achieve a powder coating with satisfactory efficiency on a workpiece. Since the electrodes are in direct contact with the powder, powder deposits occur on the electrodes, which results in significantly poorer charging.

In der US-A-4,811,898 wird darauf hingewiesen, daß bei einer Sprüheinrichtung mit Prallkörper die relative Lage von Prallkörper und Elektroden ein wesentlicher Parameter ist. Der US-A-4,228,961 ist die Verwendung von externen Elektroden entnehmbar.In US-A-4,811,898 it is pointed out that with a spray device with Impact body the relative position of the impact body and electrodes is an essential parameter is. US-A-4,228,961 shows the use of external electrodes.

Eine Pulversprüheinrichtung nach dem Oberbegriff des Anspruchs 1 ist aus der EP-A-237 249 bekannt. Die Einrichtung weist eine Kammer auf, deren Querschnitt größer ist als der Querschnitt einer Zuleitung für ein Pulver-Luft-Gemisch. In der Kammer sind eine Erdelektrode und mehrere Hochspannungselektroden angeordnet, die mit Reinigungsluft anblasbar sind.A powder spraying device according to the preamble of claim 1 is known from EP-A-237 249 known. The device has a chamber, the cross section of which is larger than the cross section of a feed line for a powder-air mixture. Are in the chamber a ground electrode and several high voltage electrodes arranged with cleaning air are inflatable.

Die Gestaltung der Kammer und insbesondere der Elektroden ist so gewählt, daß ein Plasma mit positiver Polarität und ein Plasma mit negativer Polarität entsteht. An die Plasma-Elektroden ist intermittierend eine Spannung angelegt. Versuche haben gezeigt, daß diese Maßnahmen Funkenbildung und Verschmutzung der Elektroden bewirken.The design of the chamber and in particular the electrodes is chosen so that a Plasma with positive polarity and a plasma with negative polarity are formed. To the A voltage is intermittently applied to plasma electrodes. Trials have shown that these measures cause sparking and contamination of the electrodes.

Der Erfindung liegt daher die Aufgabe zugrunde, eine Pulversprüheinrichtung anzugeben, die zu einer verbesserten Aufladung der Pulverteilchen und dadurch zu einer verbesserten Abscheiderate führen.The invention is therefore based on the object of specifying a powder spraying device, which leads to an improved charging of the powder particles and thereby to a lead to an improved deposition rate.

Diese Aufgabe wird bei einer Pulversprüheinrichtung nach dem Oberbegriff des Anspruchs 1 durch dessen kennzeichnende Merkmale gelöst. This object is achieved in a powder spraying device according to the preamble of the claim 1 solved by its characteristic features.

Es wurde festgestellt, daß insbesondere eine Pulverablagerung auf den Elektroden Ursache für eine unbefriedigende Pulverteilchenaufladung sein kann. Außerdem wurde festgestellt, daß die gesamte Kammer mit Korona ausgefüllt sein sollte und eine intensive Verwirbelung der Pulverteilchen im Bereich der Korona erfolgen sollte, um insgesamt einen guten Wirkungsgrad zu erzielen. Diese Effekte werden durch die im kennzeichnenden Teil des Anspruchs 1 angegebenen Merkmale erzielt, wie weiter unten anhand eines Ausführungsbeispiels näher beschrieben wird.It was found that, in particular, a powder deposit on the electrodes Cause of unsatisfactory powder particle charging. Besides, was found that the entire chamber should be filled with corona and one intensive swirling of the powder particles should take place in the area of the corona to achieve good overall efficiency. These effects are caused by the im characterizing part of claim 1 achieved features, as further is described in more detail below using an exemplary embodiment.

Vorteilhafte Ausgestaltungen sind in weiteren Ansprüchen angegeben. Eine Ausgestaltung bezieht sich auf die Anordnung einer oder mehrerer Außenelektroden zur weiteren Verbesserung der Aufladung bzw. zur Feldsteuerung und damit zur Steigerung des Wirkungsgrades.Advantageous refinements are specified in further claims. An embodiment refers to the arrangement of one or more external electrodes further improvement of charging or for field control and thus to increase of efficiency.

Eine andere Ausgestaltung bezieht sich auf eine variable Gestaltung des Abstandes zwischen Erdelektrode und Hochspannungselektroden, womit sich ein Optimum zwischen guter Aufladung und störenden Effekten wie Rückionisation einstellen läßt.Another embodiment relates to a variable design of the distance between earth electrode and high voltage electrodes, which is an optimum between good charging and disruptive effects such as re-ionization.

Die Erfindung wird nachstehend anhand eines in der Zeichnung dargestellten Ausführungsbeispiels näher beschrieben.The invention is described below with reference to an embodiment shown in the drawing described in more detail.

Es zeigen:

Fig. 1
eine Pulversprüheinrichtung,
Fig. 2
einen abgewandelten Auslaßbereich der Pulversprüheinrichtung, und
Fig. 3
eine Prinzipdarstellung einer Pulversprüheinrichtung mit Einleitung eines Pulver/Luft-Gemisches entgegen der Sprührichtung.
Show it:
Fig. 1
a powder spraying device,
Fig. 2
a modified outlet area of the powder spray device, and
Fig. 3
a schematic diagram of a powder spray device with the introduction of a powder / air mixture against the spray direction.

Fig. 1 zeigt eine Pulversprüheinrichtung 10. Auf ein Trägerelement 6 der Pulversprüheinrichtung 10 ist eine Verwirbelungskammer 1 aufgesetzt. Die Kammer 1 ist im Ausführungsbeispiel in bevorzugter Weise zylindrisch ausgeführt. Anstelle eines runden Querschnitts kann aber auch ein ellipsoider oder vieleckiger Querschnitt gewählt werden Wesentlich ist, daß der Querschnitt der Kammer größer ist als der Querschnitt einer Zuleitung 11 für Pulver und Luft PL. Die Pulver/Luft-Zuleitung 11 mündet quer zur Hauptachse 12 der Kammer 1 in die Kammer 1. Grundsätzlich kann das Pulver/Luft-Gemisch PL in Sprührichtung 13, entgegen der Sprührichtung 13 (Fig. 3) oder quer zur Sprührichtung 13 eingebracht werden. Die Sprührichtung 13 ist die Hauptachse 12 in Richtung eines Auslasses 3. Es hat sich gezeigt, daß eine Einleitung des Pulver/Luft-Gemisches quer zur Hauptachse 12 eine deutliche Verbesserung der Verwirbelung und eine verbesserte Aufladung bewirkt. Die in der Kammer entstehenden Turbulenzen erhöhen die Wahrscheinlichkeit, daß jedes Pulverteilchen den Bereich mit einer hohen Ladungsdichte durchquert und aufgeladen wird. Durch intensive Verwirbelung wird gleichzeitig die Dispergierung der Pulverteilchen verbessert.1 shows a powder spraying device 10. On a carrier element 6 of the powder spraying device 10, a swirl chamber 1 is placed. Chamber 1 is in the Embodiment preferably cylindrical. Instead of a round one Cross-section can also be an ellipsoidal or polygonal cross-section It is essential that the cross section of the chamber is larger than the cross section a supply line 11 for powder and air PL. The powder / air supply line 11 opens transverse to the main axis 12 of the chamber 1 into the chamber 1. Basically, the powder / air mixture PL in the spray direction 13, against the spray direction 13 (Fig. 3) or be introduced transversely to the spray direction 13. The spray direction 13 is the main axis 12 towards an outlet 3. It has been shown that an introduction of the Powder / air mixture across the main axis 12 a significant improvement in Whirling and improved charging causes. The emerging in the chamber Turbulence increases the likelihood that each powder particle will reach the area is traversed and charged with a high charge density. Through intense Whirling at the same time improves the dispersion of the powder particles.

Die Aufladung des Pulvers erfolgt durch Korona, die an nadelförmigen Hochspannungselektroden 7 erzeugt wird, die auf Hochspannungspotential liegen. Die Hochspannung wird mit Hilfe einer Hochspannungskaskade 4 erzeugt, die Teil der Pulversprüheinrichtung 10 ist, und über eine elektrische Verbindung 22 an die Hochspannungsnadeln geliefert.The powder is charged by corona, which is attached to needle-shaped high-voltage electrodes 7 is generated, which are at high voltage potential. The high tension is generated using a high-voltage cascade 4, which is part of the powder spraying device 10, and via an electrical connection 22 to the high voltage needles delivered.

Die Hochspannungselektroden 7 sind ringförmig im Bereich des Auslasses 3 angeordnet und bilden zur Erdelektrode 5 eine intensive Korona aus. Durch die gewählte Anordnung der Hochspannungsnadeln sind alle Pulverteilchen gezwungen sich durch ein Gebiet mit hoher Feldstärke und Ladungsdichte zu bewegen. Die damit bewirkte interne Aufladung kann im Bedarfsfall zusätzlich mittels im Bereich des Auslasses 3 anordenbaren Zusatzelektroden 8 über Außenaufladung noch intensiviert werden. Ein äußerer Prallkörper 9 erzeugt eine mehr oder weniger breite rotationssymmetrische Pulverwolke. Anstelle des Prallkörpers 9 kann auch eine spaltförmige Flachdüse 23 treten, die einen flachen Pulverstrahl erzeugt.The high-voltage electrodes 7 are arranged in a ring in the area of the outlet 3 and form an intensive corona to the earth electrode 5. By the chosen one Arrangement of the high voltage needles, all powder particles are forced through to move an area with high field strength and charge density. The caused with it If necessary, internal charging can also be carried out in the area of outlet 3 additional electrodes 8 that can be arranged can be intensified via external charging. On outer impact body 9 produces a more or less wide rotationally symmetrical Powder cloud. Instead of the impact body 9, a slit-shaped flat nozzle 23 can also be used kick that creates a flat powder jet.

Eine solche alternative Gestaltung des Auslaßbereiches ist in Fig. 2 dargestellt. Die sonstige Gestaltung der Pulversprüheinrichtung stimmt mit derjenigen der Fig. 1 überein, die nachstehend weiter beschrieben wird.Such an alternative design of the outlet area is shown in FIG. 2. The the other design of the powder spraying device corresponds to that of FIG. 1 which will be further described below.

Die nadelförmigen Hochspannungselektroden 7 sind ringförmig in einem Frontring 2 um den Umfang verteilt angeordnet. Der Auslaß 3 ist auf den Frontring 2 aufgesetzt. Es sollten vier bis acht Hochspannungselektroden, bevorzugt sechs Elektroden angeordnet werden. The needle-shaped high-voltage electrodes 7 are ring-shaped in a front ring 2 arranged around the circumference. The outlet 3 is placed on the front ring 2. Four to eight high-voltage electrodes, preferably six electrodes, should be arranged become.

Im Bereich des Frontrings 2 und dort wiederum in der Nähe der Hochspannungselektroden 7 wird quer zur Hauptachse 12 Hochspannungselektroden-Reinigungsluft RLH über eine Öffnung 14 eingeleitet. Sie vermindert eine Ablagerung von Pulverteilchen an den Elektroden 7. Eine besonders intensive Reinigung der Nadelelektroden 7 kann erreicht werden, wenn die Elektroden 7 jeweils in Röhrchen 15 eingesetzt und dort mit Luft RLH umspült werden.In the area of the front ring 2 and there again in the vicinity of the high-voltage electrodes 7 becomes transverse to the main axis 12 high-voltage electrode cleaning air RLH initiated via an opening 14. It reduces the build-up of powder particles on the electrodes 7. A particularly intensive cleaning of the needle electrodes 7 can can be achieved if the electrodes 7 are each inserted in tubes 15 and there with RLH air can be washed around.

Die Kammer 1 ist aus einem Isoliermaterial, wie Kunststoff, Glas oder Keramik hergestellt Gut geeignet ist eine Kammerlänge von 7 bis 15 cm, ein Durchmesser von 2 bis 4 cm und ein Abstand von 7 bis 14 cm zwischen den Hochspannungselektroden 7 und einer Erdelektrode 5. Vorteilhaft ist eine Gestaltung der Sprüheinrichtung 10, bei der der Abstand zwischen der Erdelektrode 5 und den Hochspannungselektroden 7 veränderbar ist, um ein Optimum hinsichtlich Aufladung und Rückionisation einstellbar zu machen.The chamber 1 is made of an insulating material such as plastic, glass or ceramic A chamber length of 7 to 15 cm, a diameter of 2 to 4 cm and a distance of 7 to 14 cm between the high voltage electrodes 7 and a ground electrode 5. It is advantageous to design the spray device 10 in which the distance between the earth electrode 5 and the high-voltage electrodes 7 can be changed is adjustable in order to optimize charging and re-ionization do.

Die Erdelektrode 5 ist rohrförmig ausgebildet und im Trägerelement 6 in Richtung der Hauptachse 12 zentriert angeordnet. Die rohrförmige Erdelektrode 5 hat vorzugsweise einen Durchmesser von 0,3 cm innen und 0,5 cm außen. An dem zum Kammerinneren gerichteten Ende der Erdelektrode 5 ist diese durch ein mit abgerundeten Kanten 17 versehenes Kopfteil 20 abgeschlossen. Die Erdelektrode 5 und insbesondere deren Kopfteil 20 ist mit einer Abdeckung 16 aus isoliermaterial abgedeckt, um elektrische Durchschläge zu vermeiden. Die isolierende Abdeckung 16 hat auf der Frontseite eine Abdeckungs-Öffnung 18 mit etwa 0,1 bis 0,5 cm Durchmesser.The earth electrode 5 is tubular and in the carrier element 6 in the direction of Main axis 12 arranged centered. The tubular earth electrode 5 preferably has a diameter of 0.3 cm inside and 0.5 cm outside. On the inside of the chamber directed end of the earth electrode 5 is this by a with rounded edges 17th provided headboard 20 completed. The earth electrode 5 and in particular its Headboard 20 is covered with a cover 16 made of insulating material to electrical Avoid breakthroughs. The insulating cover 16 has one on the front Cover opening 18 approximately 0.1 to 0.5 cm in diameter.

Durch die Erdelektrode 5 ist Erdelektroden-Reinigungsluft RLE geführt, die eine Pulverteilchen-Anlagerung an der Erdelektrode 5 vermeidet. Außerdem sorgt die Reinigungsluft RLE für eine zusätzliche Verwirbelung des Pulvers und es kann durch Änderung der Luftrate eine Einstellung oder Regelung des Pulver/Luft-Verhältnisses erfolgen.Through the earth electrode 5, earth electrode cleaning air RLE is guided, which is a powder particle accumulation avoids at the earth electrode 5. The cleaning air also ensures RLE for an additional swirl of the powder and it can be changed the air rate, the powder / air ratio is adjusted or regulated.

Die rohrförmige Erdelektrode 5 weist in einem Bereich vor dem Kopfteil 20 Öffnungen 19 auf, durch die die Reinigungsluft RLE aus dem Rohr heraus in einen Spalt 21 zwischen der Erdelektrode 5 und der Abdeckung 16 treten, den Kopfteil 20 umspülen und aus der Abdeckungsöffnung 18 in die Kammer 1 austreten kann. The tubular earth electrode 5 has 20 openings in an area in front of the head part 19, through which the cleaning air RLE out of the pipe into a gap 21 between kick the earth electrode 5 and the cover 16, wash around the head part 20 and can emerge from the cover opening 18 into the chamber 1.

Die zur Reinigung der Erdelektrode 5 bzw. Der Hochspannungselektroden 7 zugeführte Reinigungsluft RLE, RLH kann vorteilhaft dazu genutzt werden, um nach dem Abstellen der Zufuhr des Pulver/Luft-Gemischs PL Pulverteilchen aus der Kammer 1 herauszublasen und eine Ablagerung der Pulverteilchen auf den Elektroden 5, 7 zu vermeidenThe supplied for cleaning the earth electrode 5 and the high-voltage electrodes 7 Cleaning air RLE, RLH can be used to advantage after switching off the supply of the powder / air mixture PL powder particles from the chamber 1 blow out and a deposit of the powder particles on the electrodes 5, 7 to avoid

Fig. 3 zeigt in einer Prinzipdarstellung eine Pulversprüheinrichtung, bei der - wie weiter oben bereits angesprochen - das Pulver/Luft-Gemisch PL über die Zuleitung 11 entgegen der Sprührichtung eingeleitet wird. Außerdem ist in Fig. 3 zusätzlich ein innerer Prallteller 24 dargestellt, der die Pulverteilchen näher an die Hochspannungsnadeln 7 heranführt. Das Pulver tritt dann über Bohrungen 25 aus und trifft auf den äußeren Prallteller 9. Es versteht sich, daß die sonstigen, anhand von Fig. 1 beschriebenen Ausgestaltungen auch für die Ausführung gemäß Fig. 3 gelten.Fig. 3 shows a basic illustration of a powder spraying device, in which - how further already mentioned above - the powder / air mixture PL via the feed line 11 is initiated against the spray direction. In addition, an internal one is shown in FIG. 3 Baffle plate 24 shown, the powder particles closer to the high voltage needles 7 introduces. The powder then exits through holes 25 and strikes the outer baffle plate 9. It is understood that the other, described with reference to FIG. 1 Refinements also apply to the embodiment according to FIG. 3.

Claims (7)

  1. Powder-spraying appliance for electrostatic powder coating, at least one high-voltage electrode (7) and an earth electrode (5) being present in a chamber (1) of the spraying appliance (10) for internal powder charging, and the cross-section of the chamber (1) being larger than the cross-section of a supply conduit (11) for a powder/air mixture (PL), and
    a) the supply conduit (11) opening into the chamber (1) transversely to the spraying direction (13) or opposite to the spraying direction (13), with the result that intensive swirling of the powder is achieved,
    b) a plurality of high-voltage electrodes (7) being arranged so as to be distributed annularly in a region (2) upstream of an outlet (3) of the appliance (10), and
    c) cleaning air (RLE, RLH) being able to be blown both onto the high-voltage electrode (7) and onto the earth electrode (5), in order to avoid powder deposits on the electrodes,
    characterized in that
    d) the length of the chamber (1) is 7 to 15 cm and its diameter is 2 to 4 cm,
    e) the distance between the earth electrode (5) and high-voltage electrodes (7) is 7 to 14 cm,
    f) the earth electrode (5) is of tubular design and is arranged so as to be centred in the main axis (12) of the chamber and, at the end directed towards the chamber interior, is closed off by means of a head part (20) provided with rounded edges (17) and which is covered with a covering (16) made of insulating material.
  2. Powder-spraying appliance according to Claim 1, characterized in that the spatial distance between the earth electrode (5) and the high-voltage electrodes (7) is adjustable.
  3. Powder-spraying appliance according to Claim 1 or 2, characterized in that at least one additional electrode (8), which ensures additional external charging or field control, is arranged in the region of the outlet (3).
  4. Powder-spraying appliance according to one of the preceding claims, characterized in that a baffle body (9) or a flat nozzle (23) is arranged in the region of the outlet (3).
  5. Powder-spraying appliance according to one of the preceding claims, characterized in that the chamber (1) is produced from insulating material, such as plastic, glass or ceramic.
  6. Powder-spraying appliance according to one of the preceding claims, characterized in that the tubular earth electrode (5) has, in a region located upstream of its head part (20), orifices (19), through which the cleaning air (RLE) can pass out of the electrode tube into a gap (21) between the electrode (5) and the covering (16), flush round the head part (20) and emerge from a covering orifice (18) into the chamber (1).
  7. Powder-spraying appliance according to one of the preceding claims, characterized in that the high-voltage electrodes (7) are of needle-shaped design and are arranged in each case in small tubes (15), through which high-voltage electrode cleaning air (RLH) flows.
EP96942367A 1996-12-06 1996-12-06 Powder spraying device Expired - Lifetime EP0941145B1 (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/EP1996/005462 WO1998024555A1 (en) 1996-12-06 1996-12-06 Powder spraying device

Publications (2)

Publication Number Publication Date
EP0941145A1 EP0941145A1 (en) 1999-09-15
EP0941145B1 true EP0941145B1 (en) 2002-09-18

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Family Applications (1)

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EP96942367A Expired - Lifetime EP0941145B1 (en) 1996-12-06 1996-12-06 Powder spraying device

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US (1) US6254684B1 (en)
EP (1) EP0941145B1 (en)
JP (1) JP3866295B2 (en)
AU (1) AU1177497A (en)
CA (1) CA2273830A1 (en)
DE (1) DE59609702D1 (en)
WO (1) WO1998024555A1 (en)

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EP0978319B1 (en) 1998-08-07 2000-09-20 ABB Research Ltd. Powder spray device with external and internal charging
US6814318B2 (en) * 1999-08-18 2004-11-09 The Procter & Gamble Company Disposable cartridge for electrostatic spray device
US20040011901A1 (en) * 2000-07-10 2004-01-22 Rehman William R. Unipolarity powder coating systems including improved tribocharging and corona guns
US20030038193A1 (en) * 2000-07-11 2003-02-27 Rehman William R. Unipolarity powder coating systems including improved tribocharging and corona guns
US20020121240A1 (en) * 2000-07-11 2002-09-05 Rehman William R. Unipolarity powder coating systems including improved tribocharging and corona guns
DE10113299A1 (en) * 2001-03-16 2002-09-19 Alstom Switzerland Ltd Manufacturing conducting rods involves cutting continuous wire into sub-conductor lengths, bending sub-conductors, applying electrical insulation, assembling to make conducting rod, etc.
US20040159282A1 (en) * 2002-05-06 2004-08-19 Sanner Michael R Unipolarity powder coating systems including improved tribocharging and corona guns
US6874712B2 (en) * 2002-09-27 2005-04-05 Abb Inc. Swirl gun for powder particles
US20050098659A1 (en) * 2002-09-27 2005-05-12 Milojevic Dragoslav K. Swirl gun for powder particles
US7240861B2 (en) * 2003-08-12 2007-07-10 The University Of Western Ontario Method and apparatus for dispensing paint powders for powder coatings
ITBG20050034A1 (en) * 2005-06-03 2006-12-04 Trasmetal Spa ELECTROSTATIC PAINTING DEVICE.
DE102005045176A1 (en) * 2005-09-21 2007-03-22 Ramseier Technologies Ag applicator
US8763936B2 (en) * 2006-06-23 2014-07-01 Terronics Development Company Nozzle assembly and methods related thereto
US20200001311A1 (en) * 2017-01-30 2020-01-02 Sumitomo Chemical Company, Limited Electrostatic atomization device, information processing terminal, and control method

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US4228961A (en) * 1979-05-07 1980-10-21 Onoda Cement Co., Ltd. Electrostatic power painting head
SU1313511A1 (en) * 1985-11-26 1987-05-30 Криворожский горнорудный институт Triboelectric separator for separating minerals-dielectrics
JPH0636891B2 (en) * 1986-03-10 1994-05-18 秀雄 長坂 Powder charging device and electrostatic powder coating device
US4811898A (en) * 1987-09-21 1989-03-14 Nordson Corporation Electrostatic powder spray gun with adjustable deflector and electrostatic shield
WO1991006376A1 (en) * 1989-11-06 1991-05-16 Frederick David Haig Spray gun with corona and tubular electrodes
DE19502522A1 (en) * 1995-01-27 1996-08-01 Gema Volstatic Ag Spraying device for coating material

Also Published As

Publication number Publication date
DE59609702D1 (en) 2002-10-24
AU1177497A (en) 1998-06-29
WO1998024555A1 (en) 1998-06-11
CA2273830A1 (en) 1998-06-11
JP2001505125A (en) 2001-04-17
EP0941145A1 (en) 1999-09-15
US6254684B1 (en) 2001-07-03
JP3866295B2 (en) 2007-01-10

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