EP0170827B1 - Method of and apparatus for coating objects, and their use - Google Patents

Method of and apparatus for coating objects, and their use Download PDF

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Publication number
EP0170827B1
EP0170827B1 EP85107222A EP85107222A EP0170827B1 EP 0170827 B1 EP0170827 B1 EP 0170827B1 EP 85107222 A EP85107222 A EP 85107222A EP 85107222 A EP85107222 A EP 85107222A EP 0170827 B1 EP0170827 B1 EP 0170827B1
Authority
EP
European Patent Office
Prior art keywords
coating
guiding surface
medium
outlet aperture
arrangement according
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
EP85107222A
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German (de)
French (fr)
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EP0170827A1 (en
Inventor
Felix Walser
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Prazisions-Werkzeuge AG
Original Assignee
Prazisions-Werkzeuge AG
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Priority to AT85107222T priority Critical patent/ATE48954T1/en
Publication of EP0170827A1 publication Critical patent/EP0170827A1/en
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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
    • 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
    • B05B5/08—Plant for applying liquids or other fluent materials to objects
    • B05B5/12—Plant for applying liquids or other fluent materials to objects specially adapted for coating the interior of hollow bodies
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
    • B05B13/00—Machines or plants for applying liquids or other fluent materials to surfaces of objects or other work by spraying, not covered by groups B05B1/00 - B05B11/00
    • B05B13/06—Machines or plants for applying liquids or other fluent materials to surfaces of objects or other work by spraying, not covered by groups B05B1/00 - B05B11/00 specially designed for treating the inside of hollow bodies
    • B05B13/0618—Machines or plants for applying liquids or other fluent materials to surfaces of objects or other work by spraying, not covered by groups B05B1/00 - B05B11/00 specially designed for treating the inside of hollow bodies only a part of the inside of the hollow bodies being treated
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05C—APPARATUS FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05C7/00—Apparatus specially designed for applying liquid or other fluent material to the inside of hollow work
    • B05C7/02—Apparatus specially designed for applying liquid or other fluent material to the inside of hollow work the liquid or other fluent material being projected
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D1/00—Processes for applying liquids or other fluent materials
    • B05D1/02—Processes for applying liquids or other fluent materials performed by spraying
    • B05D1/12—Applying particulate materials
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D7/00—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials
    • B05D7/22—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials to internal surfaces, e.g. of tubes
    • B05D7/222—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials to internal surfaces, e.g. of tubes of pipes

Definitions

  • the present invention relates to a method for coating a body by means of a coating medium which is dispensed under pressure from a dispensing opening of a coating device and which, after leaving the dispensing opening, guides it along a predetermined distance between a guide surface which is continuously curved towards the body and the body to a suction device on the device is a coating arrangement with an outlet opening for a pressurized coating medium and a suction opening, in which further organs are provided to position a body to be coated at a distance above the openings, and a guiding surface between the openings for the dispensed medium to the outside is continuously curved and a use of the method or the coating arrangement for the inner coating of hollow bodies, such as can bodies, preferably in continuous series operation, such as. B. the weld of such bodies, using powder.
  • Coating processes such as powder coating processes, are known in which the coating medium, a powder carried by compressed air, is sprayed out of an outlet opening and directed toward the body part to be coated. How large is the proportion of the sprayed coating medium that is finally applied to the body part to be coated depends, among other things, on the direction and the magnitude of the forces acting on the coating medium after leaving the outlet opening.
  • EP-A-0 093 083 It is known from EP-A-0 093 083 to electrostatically assisted coating powder from a dispensing opening to be dispensed directly inside a can body against its weld seam area. Although in one embodiment the output powder jet is still guided on one side over a short distance, essentially linearly and at a predetermined angle to the can body, the driving force of the output powder is given to the body exclusively by electrostatic force and mechanical output pulse.
  • DE-OS-2 724 031 has disclosed a method and a coating arrangement for the abovementioned type.
  • the discharge opening and suction are separated by a thickened wall section that is continuously curved at the end.
  • the coating medium is essentially carried by its exit impulse against the body to be coated, the wall between the discharge opening and suction essentially forming an edge that is turbulently flowed around by the medium.
  • the purpose of the present invention is, on the basis of a method or an arrangement of the latter type, to enlarge the force field acting on the medium being released towards the body.
  • the current is also generated by applying negative pressure at the end of the curvature, according to claim 2.
  • the coating arrangement according to the invention is characterized in accordance with the characterizing part of claim 4.
  • the guide surface in order to prevent turbulence and throats that are suitable for media deposition, it is further proposed that the guide surface, according to claim 5, have the shape of an upper wing profile, with the thickest point lying against the region of the outlet opening. Furthermore, the occurrence of turbulence when the coating medium exits under pressure is largely prevented by the fact that, according to claim 6, the axis of the exit opening is at least almost parallel to the tangent of the guide surface in the exit opening area.
  • the outlet opening comprises an adjustment arrangement for setting the direction of the main flow jet direction with reference to the tangent of the guide surface in the outlet opening region.
  • Electrode arrangement Only one electrostatic potential is established on this electrode arrangement. On the body side, a second potential is determined by the latter itself or a further electrode arrangement, which is not the subject of the present invention, which forms the field-generating potential difference with the first potential.
  • the guide surface on the side remote from the outlet opening leads continuously into a suction channel, which also largely prevents turbulence in the coating medium, which could loosen the deposited medium on the body.
  • the proposed method and the proposed coating arrangement are particularly suitable for the coating of hollow bodies, such as for the continuous coating of metal can bodies, for. B. their weld with powder.
  • the coating arrangement according to the invention comprises a carrier body, for example in the form of a cylindrical arm 1.
  • a carrier body for example in the form of a cylindrical arm 1.
  • the arm 1 is supported on one side, in the figure on the left, and by the latter Page, as will be described later.
  • the channel base surface inform of the upper profile of a wing as a guiding surface is continuously convex at 13.
  • the medium pressure ventilation 7 is guided in its mouth region such that its main axis A of the mouth lies at least almost parallel to a tangent T to the wing profile formation 13.
  • an adjustable slide 15 if necessary also interchangeable, and lockable on the arm 1 by means of a screw 17, the effective outflow axis A of the medium from the outlet opening 9 can be adjusted, in particular in the direction.
  • the airfoil profile 13 continuously leads into a suction channel 19 which is incorporated into the arm 1.
  • the suction channel 19 communicates via suction bores 21, projecting radially outward, with the surface of the arm 1 facing the coating area B. It is also connected via a plurality of bores 23 to a suction line 25 which is guided through the arm 1 in an axis-parallel manner. At the exposed end of the arm 1, which is on the right in FIG. 1, the suction line 25 opens out and, as with a hose bend 27, is connected to a vacuum feed line 29, which is also returned axially through the arm 1. Suction bores 23 ′ projecting laterally on both sides also open into the suction line 25. The suction line 25 is guided further towards the supported arm end against the area of the outlet opening 9 and has, projecting radially outwards and opening in the area of the wing profile 13, bores 31.
  • wire-shaped electrodes 33 are provided in the bores 31 for applying an electrostatic field between arm 1 and body 3 to be sprayed, the electrical connection for the electrodes 33 being provided as a coaxial line through the branch Suction line 25, the arc 27 and finally the line 29 is guided to the feed side of the arm 1.
  • a seal 35 between the suction area and the wing profile 13 seals the bores 31 with the electrodes 33 mounted therein against the negative pressure prevailing in the lines 29, 25.
  • the pressurized coating medium emerges from the outlet opening 9 and is driven on the one hand by the action of the electrostatic field E between the body 3 and electrodes 33, generated by means of a high-voltage DC source 37, against the body region to be coated.
  • the medium flow is forced to flow through on a curved path P between the body 3 to be coated and the formation 13 ', preferably designed as an upper wing profile. This results in the qualitative velocity profile v shown in FIG. 2, due to the smaller radius of curvature Ri compared to the larger radius of curvature R a , which is infinite when the body 3 is straight in this direction.

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  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Wood Science & Technology (AREA)
  • Application Of Or Painting With Fluid Materials (AREA)
  • Electrostatic Spraying Apparatus (AREA)

Abstract

In order to increase the efficiency of a coating process wherein a coating medium such as, for example, powders directed from a coating medium pressure line toward a workpiece to be coated, with the coating process also including an applied electrostatic field, a coating medium which does not adhere to the workpiece is drawn off by way of a suction channel. A flow of the emerging coating medium is bent toward the workpiece that is to be coated by providing a carrier surface profile area between an outlet of the coating medium and a suction channel. By this arrangement a flow velocity gradient between the workpiece to be coated and the profile area is realized with the resulting pressure gradient from the profiled area toward the workpiece.

Description

Die vorliegende Erfindung betrifft ein Verfahren zur Beschichtung eines Körpers mittels eines unter Druck aus einer Ausgabeöffnung einer Beschichtungsvorrichtung ausgegebenen Beschichtungsmediums, welches nach Verlassen der Ausgabeöffnung entlang einer vorgegebenen Strecke zwischen einer gegen den Körper hin stetig gekrümmten Leitfläche und dem Körper zu einer Absaugung an der Vorrichtung geleitet wird, eine Beschichtungsanordnung mit einer Austrittsöffnung für ein unter Druck stehendes Beschichtungmedium sowie einer Absaugöffnung, bei der weiter Organe vorgesehen sind, um einen zu beschichtenden Körper mit Abstand über den Öffnungen zu positionieren, und eine zwischen den Öffnungen liegende Leitfläche für das ausgegebene Medium gegen aussen stetig gekrümmt ist sowie eine Verwendung des Verfahrens bzw. der Beschichtungsanordnung für die Innenbeschichtung von Hohlkörpern, wie von Dosenkörpern, vorzugsweise im Durchlauf-Seriebetrieb, so z. B. der Schweissnaht derartiger Körper, mittels Pulver.The present invention relates to a method for coating a body by means of a coating medium which is dispensed under pressure from a dispensing opening of a coating device and which, after leaving the dispensing opening, guides it along a predetermined distance between a guide surface which is continuously curved towards the body and the body to a suction device on the device is a coating arrangement with an outlet opening for a pressurized coating medium and a suction opening, in which further organs are provided to position a body to be coated at a distance above the openings, and a guiding surface between the openings for the dispensed medium to the outside is continuously curved and a use of the method or the coating arrangement for the inner coating of hollow bodies, such as can bodies, preferably in continuous series operation, such as. B. the weld of such bodies, using powder.

Es sind Beschichtungsverfahren, wie Pulverbeschichtungsverfahren, bekannt, bei denen das Beschichtungsmedium, ein durch Druckluft mitgetragenes Pulver, aus einer Austrittsöffnung versprüht wird, gegen die zu beschichtende Körperpartie hin gerichtet. Wie gross der Anteil des versprühten Beschichtungsmediums ist, der schlussendlich auf die zu beschichtende Körperpartie aufgetragen wird, hängt unter anderem von der Richtung und der Grösse der auf das Beschichtungsmedium wirkenden Kräfte nach Verlassen der Austrittsöffnung ab.Coating processes, such as powder coating processes, are known in which the coating medium, a powder carried by compressed air, is sprayed out of an outlet opening and directed toward the body part to be coated. How large is the proportion of the sprayed coating medium that is finally applied to the body part to be coated depends, among other things, on the direction and the magnitude of the forces acting on the coating medium after leaving the outlet opening.

Je grösser das Energiegefälle für das Beschichtungsmedium zwischen Austrittsöffnung und zu beschichtender Körperpartie ist, desto grösser ist der Anteil des Beschichtungsmediums, der auf den zu beschichtenden Körper auftrifft. Bekannt ist zu diesem Zwecke die Erzeugung eines elektrostatischen, hohen Feldes zwischen dem Austrittsöffnungsbreich und dem zu beschichtenden Körper, wodurch vorab oder bei Austritt geladendene Beschichtungsmediumspartikel oder Tröpfchen, gegen die zu beschichtenden Körper elektrisch getrieben werden.The greater the energy gradient for the coating medium between the outlet opening and the body part to be coated, the greater the proportion of the coating medium that strikes the body to be coated. For this purpose, it is known to generate an electrostatic, high field between the outlet opening area and the body to be coated, as a result of which coating medium particles or droplets which are charged beforehand or upon exit are electrically driven against the bodies to be coated.

So ist es aus der EP-A-0 093 083 bekannt, Beschichtungspulver aus einer Ausgabeöffnung elektrostatisch unterstützt, direkt im Innern eines Dosenkörpers gegen dessen Schweissnahtbereich auszugeben. Obwohl in einer Ausführungsform der ausgegebene Pulverstrahl über eine kurze Strecke noch einseitig, im wesentlichen linear und im vorgegebenen Winkel zum Dosenkörper geleitet ist, wird die Triebkraft des ausgegebenen Pulvers an den Körper ausschliesslich durch elektrostatische Kraft und mechanischen Ausgabeimpuls gegeben.It is known from EP-A-0 093 083 to electrostatically assisted coating powder from a dispensing opening to be dispensed directly inside a can body against its weld seam area. Although in one embodiment the output powder jet is still guided on one side over a short distance, essentially linearly and at a predetermined angle to the can body, the driving force of the output powder is given to the body exclusively by electrostatic force and mechanical output pulse.

Aus der DE-OS-2 724 031 ist ein Verfahren bzw. eine Beschichtungsanordnung obgenannter Gattung bekannt geworden. Dabei liegen Ausgabeöffnung und Absaugung durch einen verdickten Wandabschnitt, der endständig stetig gekrümmt ist, getrennt dicht nebeneinander. Das Beschichtungsmedium wird auch hier im wesentlichen durch seinen Austrittsimpuls gegen den zu beschichtenden Körper getragen, wobei die Wandung zwischen Ausgabeöffnung und Absaugung im wesentlichen eine vom Medium turbulent umströmte Kante bildet.DE-OS-2 724 031 has disclosed a method and a coating arrangement for the abovementioned type. The discharge opening and suction are separated by a thickened wall section that is continuously curved at the end. Here, too, the coating medium is essentially carried by its exit impulse against the body to be coated, the wall between the discharge opening and suction essentially forming an edge that is turbulently flowed around by the medium.

Die vorliegende Erfindung bezweckt, ausgehend von einem Verfahren bzw. einer Anordnung letztgenannter Art das auf das ausgegebene Medium wirkende Kräftefeld zum Körper hin zu vergrössern.The purpose of the present invention is, on the basis of a method or an arrangement of the latter type, to enlarge the force field acting on the medium being released towards the body.

Zu diesem Zweck zeichnet sich das erfindungsgemässe Verfahren nach dem kennzeichnenden Teil von Anspruch 1 aus.For this purpose, the method according to the invention is characterized in accordance with the characterizing part of claim 1.

Es wird damit ausgenützt, dass bei der Umlenkung eines strömenden Mediums, bedingt durch den Strömungs-Geschwindigkeitsgradienten - kleinere Geschwindigkeit entlang des Innenbogens, grössere Geschwindigkeit entlang des Aussenbogens - aufgrund der Kontinuitätsbedingung, ein Druckgradient, gerichtet vom Innenbogen nach dem Aussenbogen, und damit ein Kräftefeld, ebenso gerichtet, entsteht. Dabei muss sichergestellt sein, dass der Krümmungsradius des den Innenradius festlegenden Teiles kleiner ist als der Krümmungsradius des in diesem Bereich zu beschichtenden Körpers, was beispielsweise bei einem in dieser Richtung, d.h. in entsprechendem Schnitt, gerade ausgelegten Körper ohne weiteres der Fall ist, ist doch die Gerade als Grenzwert zunehmender Krümmungsradius zu betrachten.This takes advantage of the fact that when a flowing medium is deflected due to the flow velocity gradient - lower speed along the inner curve, higher speed along the outer curve - due to the continuity condition, a pressure gradient directed from the inner curve to the outer curve, and thus a force field , also directed, arises. It must be ensured that the radius of curvature of the part defining the inner radius is smaller than the radius of curvature of the body to be coated in this area. in a corresponding section, straight body is easily the case, the straight line is to be regarded as the limit of increasing radius of curvature.

Um eine beherrschte Strömung im Beschichtungsbereich zu erlangen, durch die genannte Krümmung, wird weiter vorgeschlagen, dass man den Strom durch krümmungsendseitiges Anlegen von Unterdruck miterzeugt, gemäss Anspruch 2.In order to achieve a controlled flow in the coating area, by means of the mentioned curvature, it is further proposed that the current is also generated by applying negative pressure at the end of the curvature, according to claim 2.

Das vorgeschlagene Verfahren, allenfalls in Kombination mit der genannten Ausführungsvariante wird erfindungsgemäss weiter dadurch mit dem bekannten elektrostatischen Verfahren zur Erzeugung eines zusätzlichen Kräftefeldes kombiniert, dass man gemäss Anspruch 3 vorgeht.The proposed method, at most in combination with the mentioned embodiment variant, is further combined according to the invention with the known electrostatic method for generating an additional force field by proceeding according to claim 3.

Zur Erfüllung der oben definierten Aufgabe der vorliegenden Erfindung zeichnet sich die erfindungsgemässe Beschichtungsanordnung nach dem kennzeichnenden Teil von Anspruch 4 aus.To achieve the object of the present invention defined above, the coating arrangement according to the invention is characterized in accordance with the characterizing part of claim 4.

Um dabei zu verhindern, dass Turbulenzen und sich für eine Mediumsablagerung anbietende Kehlen entstehen, wird weiter vorgeschlagen, dass die Leitfläche, gemäss Anspruch 5, die Form eines Tragflügeloberprofils aufweist, mit gegen den Bereich der Austrittsöffnung gelegener dickster Stelle. Im weiteren wird das Entstehen von Turbulenzen beim Austritt des Beschichtungsmediums unter Druck dadurch weitgehend verhindert, dass gemäss Anspruch 6 die Achse der Austrittsöffnung mindestens nahezu parallel zur Tangente der Leitfläche im Austrittsöffnungsbereich ist.In order to prevent turbulence and throats that are suitable for media deposition, it is further proposed that the guide surface, according to claim 5, have the shape of an upper wing profile, with the thickest point lying against the region of the outlet opening. Furthermore, the occurrence of turbulence when the coating medium exits under pressure is largely prevented by the fact that, according to claim 6, the axis of the exit opening is at least almost parallel to the tangent of the guide surface in the exit opening area.

Um dabei die Möglichkeit zu schaffen, optimale Verhältnisse suchen zu können, wird weiter gemäss Anspruch 7 vorgeschlagen, dass die Austrittsöffnung eine Verstellanordnung umfasst, zur Richtungseinstellung der Hauptström-Strahlrichtung mit Bezug auf die Tangente der Leitfläche im Austrittsöffnungsbereich.In order to create the opportunity to be able to look for optimal conditions, we will continue proposed according to claim 7 that the outlet opening comprises an adjustment arrangement for setting the direction of the main flow jet direction with reference to the tangent of the guide surface in the outlet opening region.

Zur erfindungsgemässen Kombination des bekannten Vorsehens eines elektrischen Kräftefeldes, zum zu beschichtenden Körperbereich hin, mit den oben genannten Vorkehrungen wird weiter gemäss Anspruch 8 vorgeschlagen, eine Elektrodenanordnung im Bereich der Leitfläche vorzusehen, zur Erzeugung eines elektrostatischen Potentials.For the inventive combination of the known provision of an electric force field, towards the body area to be coated, with the above-mentioned precautions, it is further proposed according to claim 8 to provide an electrode arrangement in the area of the guide surface for generating an electrostatic potential.

Es wird an dieser Elektrodenanordnung lediglich das eine elektrostatische Potential festgelegt. Körperseitig wird ein zweites Potential durch letzteren selbst, oder eine weitere Elektrodenanordnung festgelegt, nicht Gegenstand der vorliegenden Erfindung, das mit dem ersten Potential die felderzeugende Potentialdifferenz bildet.Only one electrostatic potential is established on this electrode arrangement. On the body side, a second potential is determined by the latter itself or a further electrode arrangement, which is not the subject of the present invention, which forms the field-generating potential difference with the first potential.

Gemäss Anspruch 9 führt die Leitfläche auf der der Austrittsöffnung abgelegenen Seite stetig in einen Absaugkanal, womit auch hier Turbulenzen im Beschichtungsmedium weitgehend vermieden werden, die abgelagertes Medium am Körper wieder lösen könnten.According to claim 9, the guide surface on the side remote from the outlet opening leads continuously into a suction channel, which also largely prevents turbulence in the coating medium, which could loosen the deposited medium on the body.

Um zu erreichen, dass, und dies insbesondere bei der Beschichtung von Körpern, die mit Bezug auf die Beschichtungsanordnung durchbewegt werden, auch unmittelbar nach dem Beschichtungsbereich vom Körper rückfallende Beschichtungsmediumspartien abgesaugt werden, wird vorgeschlagen, dass der Absaugkanal gemäss Anspruch 10 mit nach aussen geführten Absaugbohrungen kommuniziert.In order to ensure that, particularly in the coating of bodies which are moved with reference to the coating arrangement, parts of the coating medium falling back from the body are sucked off immediately after the coating area, it is proposed that the suction channel according to claim 10 with suction bores directed outwards communicates.

Berücksichtigt man, dass eine Druckleitung für das Beschichtungsmedium vorzusehen ist und allenfalls eine Absaugleitung, so ergibt sich eine konstruktiv einfache Möglichkeit, eine vorgesehene Elektrodenanordnung elektrisch zu kontaktieren, dadurch, dass gemäss Anspruch 11 eine elektrische Verbindung für die Elektrodenanordnung in oder an einer Über- und/oder einer Unterdruckleitung für das Medium integriert ist.If one takes into account that a pressure line is to be provided for the coating medium and possibly a suction line, then there is a structurally simple possibility of making electrical contact with an intended electrode arrangement, in that, according to claim 11, an electrical connection for the electrode arrangement in or on an over and / or a vacuum line for the medium is integrated.

Im weiteren wird die Anordnung konstruktiv bei Ausbildung gemäss Anspruch 12 wesentlich vereinfacht.Furthermore, the arrangement is structurally significantly simplified when configured according to claim 12.

Die Einsatzflexibilität einer derartigen Beschichtungsanordnung wird bei Ausbildung nach Anspruch 13 wesentlich erhöht.The versatility of such a coating arrangement is significantly increased in training according to claim 13.

Das vorgeschlagene Verfahren sowie die vorgeschlagene Beschichtungsanordnung eignen sich vorzüglich für die Beschichtung von Hohlkörpern, wie für die Innendurchlaufbeschichtung von Metalldosenkörpern, z. B. deren Schweissnaht mit Pulver.The proposed method and the proposed coating arrangement are particularly suitable for the coating of hollow bodies, such as for the continuous coating of metal can bodies, for. B. their weld with powder.

Die Erfindung wird anschliessend beispielsweise anhand von Figuren erläutert.The invention is subsequently explained, for example, using figures.

Es zeigen:

  • Fig. 1 eine schematische Darstellung einer erfindungsgemässen Beschichtungsanordnung, mit einem angedeuteten, zu beschichtenden Dosenkörper,
  • Fig. 2 schematisch den Beschichtungsbereich gemäss Fig. 1, das qualitative Profil der Strömungsgeschwindigkeit des Mediums im genannten Bereich sowie die daraus resultierende Druckverteilung und Kräftewirkung.
Show it:
  • 1 shows a schematic representation of a coating arrangement according to the invention, with an indicated can body to be coated,
  • FIG. 2 shows schematically the coating area according to FIG. 1, the qualitative profile of the flow velocity of the medium in the area mentioned, and the pressure distribution and force effect resulting therefrom.

Gemäss Fig. 1 umfasst die erfindungsgemässe Beschichtungsanordnung einen Trägerkörper, beispielsweise inform eines zylinderförmigen Armes 1. Zur Innenbeschichtung von Hohlkörpern, wie von Dosenkörpern 3, beispielsweise entlang ihrem Schweissnahtbereich 5, ist der Arm 1 einseitig gelagert, in der Fig. links, und von dieser Seite, wie noch zu beschreiben sein wird, gespiesen. Eine Druckleitung 7 für das Beschichtungsmedium, wie durch Druckluft transportierte Pulverpartikel, ragt vorerst achsial durch den Arm 1, ist dann radial umgebogen und mündet an einer Austrittsöffnung 9 in eine in den Arm 1 eingearbeitete, grundsätzlich axial ausgerichtete Rinne 11 ein.1, the coating arrangement according to the invention comprises a carrier body, for example in the form of a cylindrical arm 1. For the internal coating of hollow bodies, such as can bodies 3, for example along their weld seam area 5, the arm 1 is supported on one side, in the figure on the left, and by the latter Page, as will be described later. A pressure line 7 for the coating medium, such as powder particles transported by compressed air, initially projects axially through the arm 1, is then bent radially and opens at an outlet opening 9 into a generally axially aligned groove 11 incorporated into the arm 1.

Im Ausmündungsbereich ist die Rinnenbasisfläche inform des Oberprofils eines Tragflügels als Leitfläche bei 13 stetig konvex ausgewölbt. Die Mediumsdruckleftung 7 ist in ihrem Ausmündungsbereich so geführt, dass ihre Mündungshauptachse A, wenigstens nahezu parallel zu einer Tangente T an die Flügelprofilausformung 13 liegt. Mit Hilfe eines verstellbaren Schiebers 15, allenfalls auch auswechselbar, und am Arm 1 mittels einer Schraube 17 feststellbar, lässt sich die wirksame Ausströmungsachse A des Mediums aus der Austrittsöffnung 9, insbesondere richtungsverstellen. Der Austrittsöffnung 9 für das unter Druck stehende Beschichtungsmedium entgegengesetzt gelegen, führt das Tragflächenprofil 13 stetig in einen Absaugkanal 19 ein, der in den Arm 1 eingearbeitet ist. Der Absaugkanal 19 kommuniziert über Absaugbohrungen 21, radial nach aussen ragend, mit der dem Beschichtungsbereich B zugekehrten Oberfläche des Armes 1. Er ist weiter über eine Mehrzahl von Bohrungen 23 mit einer Absaugleitung 25 verbunden, die achsparallel durch den Arm 1 geführt ist. Am freiliegenden, in der Fig. rechts liegenden Ende des Armes 1 mündet die Absaugleitung 25 aus und ist, wie mit einem Schlauchbogen 27 mit einer Unterdruckspeiseleitung 29, die ebenfalls achsial durch den Arm 1 rückgeführt ist, verbunden. Seitlich beidseitig durchragende Absaugbohrungen 23' münden ebenfalls in die Absaugleitung 25 ein. Die Absaugleitung 25 ist gegen das abgestützte Armende hin weiter gegen den Bereich der Austrittsöffnung 9 geführt und weist, radial nach aussen ragend, und im Bereich des Tragflächenprofils 13 ausmündend, Bohrungen 31 auf.In the mouth area, the channel base surface inform of the upper profile of a wing as a guiding surface is continuously convex at 13. The medium pressure ventilation 7 is guided in its mouth region such that its main axis A of the mouth lies at least almost parallel to a tangent T to the wing profile formation 13. With the help of an adjustable slide 15, if necessary also interchangeable, and lockable on the arm 1 by means of a screw 17, the effective outflow axis A of the medium from the outlet opening 9 can be adjusted, in particular in the direction. Opposite the outlet opening 9 for the pressurized coating medium, the airfoil profile 13 continuously leads into a suction channel 19 which is incorporated into the arm 1. The suction channel 19 communicates via suction bores 21, projecting radially outward, with the surface of the arm 1 facing the coating area B. It is also connected via a plurality of bores 23 to a suction line 25 which is guided through the arm 1 in an axis-parallel manner. At the exposed end of the arm 1, which is on the right in FIG. 1, the suction line 25 opens out and, as with a hose bend 27, is connected to a vacuum feed line 29, which is also returned axially through the arm 1. Suction bores 23 ′ projecting laterally on both sides also open into the suction line 25. The suction line 25 is guided further towards the supported arm end against the area of the outlet opening 9 and has, projecting radially outwards and opening in the area of the wing profile 13, bores 31.

Koaxial gelagert und fixiert, sind in den Bohrungen 31 drahtförmige Elektroden 33 zum Anlegen eines elektrostatischen Feldes zwischen Arm 1 und zu besprühendem Körper 3 vorgesehen, wobei der elektrische Anschluss für die Elektroden 33 als Koaxialleitung durch die Absaugleitung 25, den Bogen 27 und schliesslich die Leitung 29 an die Zuspeiseseite des Armes 1 geführt ist. Eine Dichtung 35 zwischen Absaugbereich und Tragflächenprofil 13 dichtet die Bohrungen 31 mit den darin gelagerten Elektroden 33 gegen den in den Leitungen 29, 25 herrschenden Unterdruck ab.Mounted and fixed coaxially, wire-shaped electrodes 33 are provided in the bores 31 for applying an electrostatic field between arm 1 and body 3 to be sprayed, the electrical connection for the electrodes 33 being provided as a coaxial line through the branch Suction line 25, the arc 27 and finally the line 29 is guided to the feed side of the arm 1. A seal 35 between the suction area and the wing profile 13 seals the bores 31 with the electrodes 33 mounted therein against the negative pressure prevailing in the lines 29, 25.

Das unter Druck stehende Beschichtungsmedium tritt aus der Austrittsöffnung 9 aus und wird einerseits durch Wirkung des elektrostatischen Feldes E zwischen Körper 3 und Elektroden 33, erzeugt mittels einer Hochspannungs-DC-Quelle 37 gegen den zu beschichtenden Körperbereich getrieben. Zusätzlich und wie aus Fig. 2 ersichtlich, wird der Mediumsstrom gezwungen, auf gekrümmter Bahn P zwischen zu beschichtendem Körper 3 und Ausformung 13', vorzugsweise als Tragflügel-Oberprofil ausgebildet, durchzuströmen. Dabei entsteht das in Fig. 2 dargestellte, qualitative Geschwindigkeitsprofil v, bedingt durch den kleineren Innenkrümmungsradius Ri im Vergleich zum grösseren Aussenkrümmungsradius Ra, der bei in dieser Richtung geradem Körper 3 unendlich ist. Es entsteht somit im Bereiche des zu beschichtenden Körpers 3 wegen der höheren Strömungsgeschwindigkeit v mit Bezug auf dem der Ausformung 13' folgenden Medium, ein Unterdruck mit, wie in Fig. 2 gerichtetem Kraftfeld F. Auf diese Art und Weise wird, allenfalls in Ergänzung zum elektrostatischen Kraftfeld, das Beschichtungsmedium gegen den zu beschichtenden Körper 3 hin getrieben. Nicht am Körper 3 haftendes Beschichtungsmaterial, wie Pulver oder Tröpfchen, wird am Absaugkanal 19 und durch die Bohrungen 23 abgesaugt, nachmalig vom Körper 3 rückfallendes Beschichtungsmaterial durch die mit dem Absaugkanal 19 kommunizierenden Bohrungen 21 bzw. 23'.The pressurized coating medium emerges from the outlet opening 9 and is driven on the one hand by the action of the electrostatic field E between the body 3 and electrodes 33, generated by means of a high-voltage DC source 37, against the body region to be coated. In addition and as can be seen from FIG. 2, the medium flow is forced to flow through on a curved path P between the body 3 to be coated and the formation 13 ', preferably designed as an upper wing profile. This results in the qualitative velocity profile v shown in FIG. 2, due to the smaller radius of curvature Ri compared to the larger radius of curvature R a , which is infinite when the body 3 is straight in this direction. Thus, in the area of the body 3 to be coated, because of the higher flow velocity v with respect to the medium following the formation 13 ', a negative pressure is created with the force field F as directed in FIG. 2 electrostatic force field, the coating medium driven against the body 3 to be coated. Coating material which is not adhering to the body 3, such as powder or droplets, is sucked off at the suction channel 19 and through the bores 23, and coating material which falls back from the body 3 through the bores 21 and 23 'communicating with the suction channel 19.

Es versteht sich von selbst, dass der elektrische Anschluss für die Elektroden 33 auch via Druckleitung 7 in analoger Weise erfolgen kann, wobei dann die Bohrungen 31 gegen die Druckleitung 7 mit einer zur Dichtung 35 analogen Dichtung verschlossen werden.It goes without saying that the electrical connection for the electrodes 33 can also take place in an analogous manner via the pressure line 7, the bores 31 then being closed off from the pressure line 7 with a seal analogous to the seal 35.

Mit der beschriebenen Anordnung bzw. dem dadurch realisierten Verfahren wird eine wesentliche Erhöhung der Ablagerungsmenge pro Zeiteinheit des Beschichtungsmediums am zu beschichtenden Körper 3 erzielt, was insbesondere bei schnellen Durchlaufverfahren wesentlich ist, d.h. wenn der Körper 3 gemäss Fig. 1 in der mit S bezeichneten Richtung rasch durchbewegt wird.With the arrangement described and the method implemented thereby, a substantial increase in the amount of deposits per unit time of the coating medium on the body 3 to be coated is achieved, which is particularly important in the case of rapid continuous processes, i.e. if the body 3 according to FIG. 1 is moved rapidly in the direction denoted by S.

Claims (14)

1. Method for coating a body (3) with a coating medium dispensed under pressure from an outlet aperture (9) of a coating machine (1), which, after leaving the outlet aperture (9), is guided along a predetermined path between a guiding surface (13) steadily curved towards the body and the body (3) to suction means (19) on the machine, characterised in that in order to utilise the driving force (F) directed towards the body (3) which force, due the guiding surface (13) being curved towards the body (3) acts upon the medium flowing along this guiding surface, the length of the path is chosen so as to be essentially longer than the smallest distance between the curved guiding surface (13) and the body (3).
2. Method according to claim 1, characterised in that the medium flow is co-generated by applying negative pressure to the suction means (19).
3. Method according to claim 1 or 2, characterised in that an electrostatic field (E) is applied between an area of the guiding surface and the body (3).
4. Coating arrangement comprising an outlet aperture (9) for a pressurized coating medium and a suction aperture (19), on which further, means are provided for positioning a body (3) to be coated at a distance above the apertures (9, 19), and a guiding surface (13) for the dispensed medium is steadily curved between the apertures, characterised in that, in order to utilise the driving force (F) towards the body (3), which due to the guiding surface (13) being curved towards the body (3) acts upon the medium flowing along this guiding surface (13), the distance between the apertures is significantly larger than the smallest guiding surface/body distance defined by the guiding surface (13) and the means for the body (3).
5. Coating arrangement according to claim 4, characterised in that the guiding surface (13) is in the form of an aerofoil upper profile with the thik- kest point situated towards the area of the outlet aperture (9).
6. Coating arrangement according to claim 4 or 5, characterised in that axis (A) of outlet aperture (9) extends at least approximately parallel to tangent (T) of guiding surface (13) in the area of outlet aperture (9).
7. Coating arrangement according to one of claims 4 to 6, characterised in that the outlet aperture (9) comprises an adjusting arrangement (15) for adjusting the direction of the main jet from the outlet aperture relative to the tangent (T) of the guiding surface (13) in the area of the outlet aperture.
8. Coating arrangement according to one of claims 4 to 7, characterised in that in the area of the guiding surface (13) an electrode arrangement (33) is provided for generating an electrostatic potential (Φ).
9. Coating arrangement according to one of claims 4 to 8 characterised in that the guiding surface (13) steadily leads into a suction channel (19) on the side facing away from the outlet aperture (9).
10. Coating arrangement according to claim 9, characterised in that the suction channel (19) communicates with suction bores (21, 23') leading to the outside and is connected with a negative pressure line (29).
11. Coating arrangement according to claim 8, characterised in that an electrical connection for the electrode arrangement (33) is integrated in or on a positive and/or negative pressure line (7, 29) for the medium.
12. Coating arrangement according to claim 11, characterised in that at least one bore (31) communicating with a medium line (7) to the outlet aperture (9) or with the suction aperture (19) is provided which bore opens into the guiding surface (13) and in that it contains a preferably wire-shaped, preferably coaxial electrode (33) extending at least and preferably near to the outlet of the bore (31), the bore (31) being sealed (35) so as to be medium-tight both in direction of the medium line and the suction aperture (19).
13. Coating arrangement according to one of claims 4 to 12, characterised in that the arrangement is shaped as a cantilevered arm (1) with one-sided supply.
14. Use of the method according to one of claims 1 to 3 or the arrangement according to one of claims 4 to 13 for coating the inside of hollow bodies, such as the weld of metal can bodies, with powder, preferably by a through-flow series production process.
EP85107222A 1984-07-13 1985-06-12 Method of and apparatus for coating objects, and their use Expired EP0170827B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT85107222T ATE48954T1 (en) 1984-07-13 1985-06-12 METHOD FOR COATING A BODY, COATING ARRANGEMENT AND USE OF THE METHOD OR. THE ARRANGEMENT.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CH3421/84 1984-07-13
CH3421/84A CH666630A5 (en) 1984-07-13 1984-07-13 METHOD AND ARRANGEMENT FOR COATING A BODY.

Publications (2)

Publication Number Publication Date
EP0170827A1 EP0170827A1 (en) 1986-02-12
EP0170827B1 true EP0170827B1 (en) 1989-12-27

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EP85107222A Expired EP0170827B1 (en) 1984-07-13 1985-06-12 Method of and apparatus for coating objects, and their use

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US (1) US4826704A (en)
EP (1) EP0170827B1 (en)
JP (1) JPH069676B2 (en)
AT (1) ATE48954T1 (en)
CH (1) CH666630A5 (en)
DE (1) DE3574940D1 (en)

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Publication number Priority date Publication date Assignee Title
DE8712547U1 (en) * 1987-09-17 1987-11-19 Behr-Industrieanlagen GmbH & Co, 7121 Ingersheim Workpiece carrier for electrostatic workpiece coating
US4931306A (en) * 1988-11-25 1990-06-05 Vapor Technologies Inc. High penetration deposition process and apparatus
US5725670A (en) 1994-02-18 1998-03-10 Nordson Corporation Apparatus for powder coating welded cans
US6344109B1 (en) 1998-12-18 2002-02-05 Bki Holding Corporation Softened comminution pulp
US9181803B2 (en) 2004-12-22 2015-11-10 Magna Powertrain Inc. Vane pump with multiple control chambers
US20110311855A1 (en) * 2009-09-03 2011-12-22 Shufu Peng Methods and systems for making separators and devices arising therefrom
US9109597B2 (en) 2013-01-15 2015-08-18 Stackpole International Engineered Products Ltd Variable displacement pump with multiple pressure chambers where a circumferential extent of a first portion of a first chamber is greater than a second portion

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE611131C (en) * 1933-11-01 1935-03-22 Heinrich Projahn Process for lining the inside of centrifugally cast pipes during the remuneration of the pipes in the annealing furnace and the device used for this purpose
US3868925A (en) * 1970-08-14 1975-03-04 Nat Steel Corp Electrostatic coating of metal powder on metal strip
DE2058350A1 (en) * 1970-11-27 1972-05-31 Bayer Ag Method and device for the inner coating of pipes with a powdery, sinterable material
DE2724031A1 (en) * 1977-05-27 1978-12-14 Metallgesellschaft Ag Metallic tubes coated internally with plastics layer - using double walled lance with radial spigot to blow plastics at heated wall and remove excess
US4215648A (en) * 1978-08-23 1980-08-05 The Continental Group, Inc. Electrostatic air/powder stripe applicator
GR73507B (en) * 1978-08-23 1984-03-07 Continental Group
EP0093083B2 (en) * 1982-04-27 1993-11-24 Siegfried Frei Process for applying powder in strip form and powder application device

Also Published As

Publication number Publication date
EP0170827A1 (en) 1986-02-12
CH666630A5 (en) 1988-08-15
ATE48954T1 (en) 1990-01-15
US4826704A (en) 1989-05-02
DE3574940D1 (en) 1990-02-01
JPS6133272A (en) 1986-02-17
JPH069676B2 (en) 1994-02-09

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