EP0455110B1 - Plant for coating series of work pieces with conductive coating material - Google Patents

Plant for coating series of work pieces with conductive coating material Download PDF

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Publication number
EP0455110B1
EP0455110B1 EP91106543A EP91106543A EP0455110B1 EP 0455110 B1 EP0455110 B1 EP 0455110B1 EP 91106543 A EP91106543 A EP 91106543A EP 91106543 A EP91106543 A EP 91106543A EP 0455110 B1 EP0455110 B1 EP 0455110B1
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EP
European Patent Office
Prior art keywords
filling
tube
filling piston
installation
coating
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
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EP91106543A
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German (de)
French (fr)
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EP0455110A1 (en
Inventor
Günther Dipl.-Ing. Birner
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Duerr GmbH
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Duerr 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
    • B05B5/16—Arrangements for supplying liquids or other fluent material
    • B05B5/1608—Arrangements for supplying liquids or other fluent material the liquid or other fluent material being electrically conductive
    • B05B5/1616—Arrangements for supplying liquids or other fluent material the liquid or other fluent material being electrically conductive and the arrangement comprising means for insulating a grounded material source from high voltage applied to the material
    • B05B5/1625—Arrangements for supplying liquids or other fluent material the liquid or other fluent material being electrically conductive and the arrangement comprising means for insulating a grounded material source from high voltage applied to the material the insulating means comprising an intermediate container alternately connected to the grounded material source for filling, and then disconnected and electrically insulated therefrom
    • B05B5/1641—Arrangements for supplying liquids or other fluent material the liquid or other fluent material being electrically conductive and the arrangement comprising means for insulating a grounded material source from high voltage applied to the material the insulating means comprising an intermediate container alternately connected to the grounded material source for filling, and then disconnected and electrically insulated therefrom an additional container being provided downstream the intermediate container
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
    • B05B9/00—Spraying apparatus for discharge of liquids or other fluent material, without essentially mixing with gas or vapour
    • B05B9/03—Spraying apparatus for discharge of liquids or other fluent material, without essentially mixing with gas or vapour characterised by means for supplying liquid or other fluent material
    • B05B9/04—Spraying apparatus for discharge of liquids or other fluent material, without essentially mixing with gas or vapour characterised by means for supplying liquid or other fluent material with pressurised or compressible container; with pump

Definitions

  • the invention relates to a system according to the preamble of claim 1.
  • the spray head of rotary atomizers or the like is connected to high voltage in order to thereby generate the field which charges the sprayed coating particles between the spray head and the grounded object to be coated.
  • a coating material with high electrical conductivity such as the environmentally friendly water-soluble paints
  • the insulation resistance via the line connecting the spray head to the paint supply system is too low if the supply system is at ground potential.
  • the supply system which usually consists of ring lines for the individual colors, is to be grounded, since otherwise not only would considerable expenditure of insulation be necessary, but also the danger of explosive discharges would exist due to the large electrical capacity.
  • a separate storage container for each color, which is arranged insulated from earth and from the other containers and via a color changer and a connecting line which is at high voltage potential horizontal spray device feeds.
  • the connecting line is flushed with a given color and before changing to another color with solvent (water) and dried with compressed air in order to maintain the required insulation for the container which is subsequently connected to the spraying device.
  • solvent water
  • this system is structurally complex and bulky. There are also color losses when emptying and flushing the insulating lines and the need to dispose of the flushing agent.
  • the same problem occurs with a method known from DE-A-37 17 929, in which the color changer of an earthed supply system leads to an intermediate container and from there leads to the spraying device for electrical insulation and is dried.
  • the invention has for its object to provide a simple system that requires little space and little construction and tax.
  • the invention has the advantage that the movable intermediate container can be moved up and down between its end positions more easily and more quickly. It is also advantageous to close the movement range of the intermediate container to the outside by means of an insulating tube, which does not increase the space requirement. It is also important that the high voltage does not have to be switched off during the coating operation, since the coating device is always isolated from the supply system during operation.
  • the part of the system shown consists essentially of an intermediate container arrangement, which is accommodated in its entirety in its elongated closed and pressure-resistant tube 1, which is made of insulating material such as. B. acrylic glass is formed.
  • the tube 1 can have a circular cylindrical or any other cross-section and be set up with a vertical longitudinal axis or be mounted on a wall, for example a spray booth.
  • the tube 1 In its lower part, the tube 1 forms a storage container 3. At the lower end of the tube, that is to say in the bottom of the storage container 3, which lowers in a funnel-like manner or in some other way to a deepest point, the tube 1 has a closable outlet 4 for this at this point coating material located in the reservoir 3.
  • the outlet 4 can contain a valve and is connected to a line 5 leading to a coating device (not shown).
  • a return line 6 leading into the storage container 3 can branch off from the line 5. Since the content of the storage container 3 is electrically connected to the coating device by the conductive coating material, it is constantly at high voltage during operation like this.
  • the reservoir 3 is closed at the top by a horizontal partition 7 which contains an axial opening 8 forming the container inlet.
  • the part of the tube interior lying above the dividing wall 7 contains a filling piston 10 which is slidably displaceable vertically on the inside wall of the tube and which serves to fill the storage container 3.
  • the filling piston 10 can consist of an open-topped cylindrical container of the shape shown made of insulating material.
  • Its side wall 11 is located at a short distance parallel to the cylindrical inner wall of the tube 1 and has at the upper edge and on the piston head 12 each a radially projecting guide flange 14 or 15 lying airtight against the inner wall of the tube abuts the upper edge of its side wall 11 on a horizontal cover closing the tube 1 and can be filled through an inlet 18 of the cover, and a lower position in which the piston crown 12 rests on the partition 7 and the filling piston 10 in the reservoir 3 is emptied.
  • the filling piston 10 has an outlet valve 20 which is automatically opened by external control when the emptying position is reached.
  • the outlet valve 20 may have a downward actuating pin 21, which is pushed upwards to open the valve by an upward projection on the top of the partition 7, whereupon the coating material by gravity from the filling piston 10 through the inlet opening 8 in the reservoir 3 can flow.
  • a compressed air inlet 23 leads into the tube 1, which opens into a recess at the upper side edge of the partition 7, that is to say directly below the underside of the filling piston 10 seated on the partition 7 and serving as the piston surface.
  • the compressed air inlet 23 is connected to a compressed air line 25 via a valve 24.
  • the upper sensor 28 responds as soon as the liquid level in the storage container 3 reaches the desired maximum level, while the lower sensor 29 when the desired minimum level is undershot appeals.
  • sensors 30, 31 and 32 are attached to the tube wall one above the other, which sensors may consist of initiators known per se and respond when the filling piston 10 approaches.
  • the upper sensor 30 responds when the filling piston 10 reaches its upper end position.
  • the sensor 31 attached somewhat below the sensor 30 responds when the filling piston 10 is somewhat out of its upper end position has sunk down.
  • the sensor 32 attached further below in the vicinity of the partition 7 responds when the filling piston is seated on the partition 7.
  • the sensors 28 to 32 control (via the control lines shown in dashed lines) the compressed air valve 24 and a filling valve 35 which is connected to a line 36 of the earthed supply system leading to the inlet 18 of the pipe 1 or could also be installed in the inlet 18.
  • a timer 33 can be connected downstream of the sensor 32.
  • the sensor 30 responsive to this position opens the filling valve 35 so that the filling piston 10 is filled through the opening 18.
  • the cover 17 there is also a vent valve 38.
  • the filling piston begins to drop after a short time due to its increasing mass. It is full when it reaches the sensor 31, which then closes the filling valve 35 and can also switch off the compressed air at the valve 24 or reduce the pressure.
  • the full filling piston 10 drops again to the partition 7 and empties into the reservoir 3. After a z. B. by the timer 33 determined delay time, the process is repeated until the sensor 28 reports reaching a maximum level that should not be exceeded.
  • the storage container 3 can be emptied non-stop even during the filling processes described above and its contents remain constantly at the high-voltage potential of the spraying device to which it is connected via the conductive coating material in the line 5. Due to the distance of the above-mentioned maximum filling level in the container 3 from the grounded supply system on the top of the tube 1, which is dimensioned sufficiently larger than the flashover distance of the high voltage, the parts of the system which are at different potentials are constantly isolated from one another.
  • the arrangement described requires little construction effort and can be realized in a compact and space-saving manner, which is of particular interest in the case of a large number of selectable coating materials of different colors, for each of which an insulating container arrangement of the type described is required.
  • a relatively small filling piston for a content of approximately 1 l and a correspondingly dimensioned tube 1 with a diameter of approximately 15 cm may be sufficient.
  • the tubes 1 corresponding to the different colors can be assembled in a common unit.

Landscapes

  • Electrostatic Spraying Apparatus (AREA)

Description

Die Erfindung betrifft eine Anlage gemäß dem Oberbegriff des Anspruchs 1.The invention relates to a system according to the preamble of claim 1.

In üblichen elektrostatischen Beschichtungsanlagen, wie sie insbesondere zum Lackieren von Fahrzeugrohkarossen verwendet werden, legt man den Sprühkopf von Rotationszerstäubern od. dgl. an Hochspannung, um dadurch das die versprühten Beschichtungspartikel aufladende Feld zwischen dem Sprühkopf und dem geerdeten, zu beschichtenden Gegenstand zu erzeugen. Hierbei tritt das Problem auf, daß bei Verwendung eines Beschichtungsmaterials hoher elektrischer Leitfähigkeit wie namentlich der umweltfreundlichen wasserlöslichen Lacke der Isolationswiderstand über die den Sprühkopf mit dem Lackversorgungssystem verbindende Leitung zu gering ist, wenn das Versorgungssystem auf Erdpotential liegt. Das gewöhnlich aus Ringleitungen für die einzelnen Farben bestehende Versorgungssystem soll geerdet sein, da andernfalls nicht nur erheblicher Isolationsaufwand erforderlich wäre, sondern auch wegen der großen elektrischen Kapazität die Gefahr explosionsartiger Entladungen bestehen würde.In conventional electrostatic coating systems, such as those used in particular for painting vehicle body shells, the spray head of rotary atomizers or the like is connected to high voltage in order to thereby generate the field which charges the sprayed coating particles between the spray head and the grounded object to be coated. The problem arises here that when using a coating material with high electrical conductivity, such as the environmentally friendly water-soluble paints, the insulation resistance via the line connecting the spray head to the paint supply system is too low if the supply system is at ground potential. The supply system, which usually consists of ring lines for the individual colors, is to be grounded, since otherwise not only would considerable expenditure of insulation be necessary, but also the danger of explosive discharges would exist due to the large electrical capacity.

Bei einer aus der DE-A- 30 14 221 bekannten Beschichtungsanlage für elektrisch leitfähige Materialien ist für jede Farbe ein eigener Vorratsbehälter vorgesehen, der gegen Erde und gegen die jeweils anderen Behälter isoliert angeordnet ist und über einen Farbwechsler und eine Verbindungsleitung die auf Hochspannungspotential liegende Sprühvorrichtung speist. Die Verbindungsleitung wird nach Beendigung des Beschichtungsbetriebes mit einer gegebenen Farbe und vor dem Wechsel zu einer anderen Farbe mit Lösungsmittel (Wasser) gespült und mit Druckluft getrocknet, um die erforderliche Isolierung zu dem anschließend mit der Sprühvorrichtung verbundenen Behälter aufrechtzuerhalten. Insbesondere bei einer großen Anzahl wählbarer Farben und entsprechender Behälter ist diese Anlage baulich aufwendig und sperrig. Ferner ergeben sich Farbverluste beim Entleeren und Spülen der isolierenden Leitungen und die Notwendigkeit der Entsorgung des Spülmittels. Dasselbe Problem tritt bei einem aus der DE-A- 37 17 929 bekannten Verfahren auf, bei dem vom Farbwechsler eines geerdeten Versorgungssystems zu einem Zwischenbehälter und von diesem zur Sprühvorrichtung führende Leitungen zur elektrischen Isolation gespült und getrocknet werden.In a coating system for electrically conductive materials known from DE-A-30 14 221, a separate storage container is provided for each color, which is arranged insulated from earth and from the other containers and via a color changer and a connecting line which is at high voltage potential horizontal spray device feeds. After the coating operation has ended, the connecting line is flushed with a given color and before changing to another color with solvent (water) and dried with compressed air in order to maintain the required insulation for the container which is subsequently connected to the spraying device. Especially with a large number of selectable colors and corresponding containers, this system is structurally complex and bulky. There are also color losses when emptying and flushing the insulating lines and the need to dispose of the flushing agent. The same problem occurs with a method known from DE-A-37 17 929, in which the color changer of an earthed supply system leads to an intermediate container and from there leads to the spraying device for electrical insulation and is dried.

Dieses Problem wird teilweise bei einem aus der DE-C- 29 00 660 bekannten System vermieden, bei dem das Beschichtungsmaterial von einer geerdeten Ringleitung zunächst in einen isoliert angeordneten ersten Zwischenbehälter gelangt und aus diesem dann in einen zweiten Zwischenbehälter, dessen Ausgang ständig mit der auf Hochspannung liegenden Sprühvorrichtung verbunden ist. Durch ausreichend großen Abstand und zweckmäßig bewegbare Verbindungsrohre oder durch Auf- und Abbewegen des ersten Zwischenbehälters wird beim Füllen des ersten Zwischenbehälters dessen Inhalt vom zweiten Zwischenbehälter elektrisch isoliert und beim Füllen des an Hochspannung liegenden zweiten Zwischenbehälters der erste Zwischenbehälter vom geerdeten Vorratssystem isoliert. Der erste Zwischenbehälter wird vor dem Entleeren in den zweiten Zwischenbehälter elektrisch aufgeladen, um Spannungsüberschläge zu vermeiden. Das bekannte System ist aber baulich aufwendig und bereitet Schwierigkeiten wegen der offenen Anordnung des auf und ab bewegbaren Zwischenbehälters. Außerdem benötigt der mit der Beschichtungsvorrichtung verbundene Vorratsbehälter eine nachgeschaltete Förderpumpe zum Entleeren.This problem is partially avoided in a system known from DE-C-29 00 660, in which the coating material first arrives from an earthed ring line in an insulated first intermediate container and then from this into a second intermediate container, the output of which is constantly the same High voltage lying spray device is connected. By means of a sufficiently large distance and expediently movable connecting pipes or by moving the first intermediate container up and down, the contents of the first intermediate container are electrically insulated from the second intermediate container and when the second intermediate container, which is connected to high voltage, is filled, the first intermediate container is isolated from the grounded storage system. The first intermediate container is electrically charged before emptying into the second intermediate container in order to avoid voltage flashovers. However, the known system is structurally complex and presents difficulties because of the open arrangement of the intermediate container which can be moved up and down. Also needed the storage container connected to the coating device has a downstream feed pump for emptying.

Ausgehend von dem aus der erwähnten DE-C- 29 00 660 bekannten System liegt der Erfindung die Aufgabe zugrunde, eine einfache Anlage zu schaffen, die mit geringem Platzbedarf und wenig Bau- und Steueraufwand auskommt.Based on the system known from DE-C-29 00 660, the invention has for its object to provide a simple system that requires little space and little construction and tax.

Diese Aufgabe wird durch die im Anspruch 1 gekennzeichnete Anlage gelöst.This object is achieved by the system characterized in claim 1.

Die Erfindung hat den Vorteil, daß der bewegbare Zwischenbehälter einfacher und auch schneller zwischen seinen Endpositionen auf und ab bewegt werden kann. Vorteilhaft ist auch der Abschluß des Bewegungsbereiches des Zwischenbehälters nach außen durch ein isolierendes Rohr, das den Platzbedarf nicht vergrößert. Im übrigen ist wichtig, daß die Hochspannung während des Beschichtungsbetriebes nicht abgeschaltet werden muß, da die Beschichtungsvorrichtung im Betrieb stets vom Versorgungssystem isoliert ist.The invention has the advantage that the movable intermediate container can be moved up and down between its end positions more easily and more quickly. It is also advantageous to close the movement range of the intermediate container to the outside by means of an insulating tube, which does not increase the space requirement. It is also important that the high voltage does not have to be switched off during the coating operation, since the coating device is always isolated from the supply system during operation.

An einem in der Zeichnung schematisch dargestellten Ausführungsbeispiel wird die Erfindung näher erläutert.The invention is explained in more detail using an exemplary embodiment shown schematically in the drawing.

Der dargestellte Teil der Anlage besteht im wesentlichen aus einer Zwischenbehälteranordnung, die in ihrer Gesamtheit in ihrem langgestreckten geschlossenen und druckfest ausgebildeten Rohr 1 untergebracht ist, das aus Isoliermaterial wie z. B. Acrylglas gebildet ist. Das Rohr 1 kann einen kreiszylindrischen oder beliebigen sonstigen Querschnitt haben und mit vertikaler Längsachse aufgestellt oder an einer Wand beispielsweise einer Sprühkabine montiert werden.The part of the system shown consists essentially of an intermediate container arrangement, which is accommodated in its entirety in its elongated closed and pressure-resistant tube 1, which is made of insulating material such as. B. acrylic glass is formed. The tube 1 can have a circular cylindrical or any other cross-section and be set up with a vertical longitudinal axis or be mounted on a wall, for example a spray booth.

In seinem unteren Teil bildet das Rohr 1 einen Vorratsbehälter 3. Am unteren Rohrende, also im Boden das Vorratsbehälters 3, der sich trichterartig oder in sonstiger Weise schräg zu einer tiefsten Stelle absenkt, hat das Rohr 1 an dieser Stelle einen verschließbaren Auslaß 4 für das im Vorratsbehälter 3 befindliche Beschichtungsmaterial. Der Auslaß 4 kann ein Ventil enthalten und ist an eine zu einer (nicht dargestellten) Beschichtungsvorrichtung führende Leitung 5 angeschlossen. Von der Leitung 5 kann eine oben in den Vorratsbehälter 3 führende Rücklaufleitung 6 abzweigen. Da der Inhalt des Vorratsbehälters 3 durch das leitfähige Beschichtungsmaterial elektrisch mit der Beschichtungsvorrichtung verbunden ist, liegt er im Betrieb wie diese ständig auf Hochspannung. Nach oben ist der Vorratsbehälter 3 durch eine horizontale Trennwand 7 abgeschlossen, die eine den Behältereinlaß bildende axiale Öffnung 8 enthält.In its lower part, the tube 1 forms a storage container 3. At the lower end of the tube, that is to say in the bottom of the storage container 3, which lowers in a funnel-like manner or in some other way to a deepest point, the tube 1 has a closable outlet 4 for this at this point coating material located in the reservoir 3. The outlet 4 can contain a valve and is connected to a line 5 leading to a coating device (not shown). A return line 6 leading into the storage container 3 can branch off from the line 5. Since the content of the storage container 3 is electrically connected to the coating device by the conductive coating material, it is constantly at high voltage during operation like this. The reservoir 3 is closed at the top by a horizontal partition 7 which contains an axial opening 8 forming the container inlet.

Der über der Trennwand 7 liegende Teil des Rohrinnenraums enthält einen vertikal an der Rohrinnenwand gleitend verschiebbar gelagerten Füllkolben 10, der zum Füllen des Vorratsbehälters 3 dient. Der Füllkolben 10 kann aus einem oben offenen zylindrischen Behälter der dargestellten Form aus Isoliermaterial bestehen. Seine Seitenwand 11 liegt mit geringem Abstand parallel zur zylindrischen Innenwand des Rohres 1 und hat am oberen Rand sowie am Kolbenboden 12 je einen radial vorspringenden luftdicht an der Rohrinnenwand anliegenden Führungsflansch 14 bzw. 15. Der Füllkolben ist zwischen einer oberen Position, bei der er mit dem oberen Rand seiner Seitenwand 11 an einem das Rohr 1 verschließenden horizontalen Deckel anstößt und durch einen Einlaß 18 des Deckels gefüllt werden kann, und einer unteren Position bewegbar, bei der der Kolbenboden 12 auf der Trennwand 7 aufsitzt und der Füllkolben 10 in den Vorratsbehälter 3 entleert wird. An der tiefsten Stelle seines sich z. B. trichterförmig absenkenden Bodens hat der Füllkolben 10 ein Auslaßventil 20, das beim Erreichen der Entleerungsposition durch externe Steuerung selbsttätig geöffnet wird. Gemäß dem dargestellten Beispiel kann das Auslaßventil 20 einen nach unten weisenden Betätigungsstift 21 haben, der zum Öffnen des Ventils von einem nach oben weisenden Vorsprung auf der Oberseite der Trennwand 7 hochgedrückt wird, worauf das Beschichtungsmaterial durch Schwerkraft aus dem Füllkolben 10 durch die Einlaßöffnung 8 in den Vorratsbehälter 3 fließen kann.The part of the tube interior lying above the dividing wall 7 contains a filling piston 10 which is slidably displaceable vertically on the inside wall of the tube and which serves to fill the storage container 3. The filling piston 10 can consist of an open-topped cylindrical container of the shape shown made of insulating material. Its side wall 11 is located at a short distance parallel to the cylindrical inner wall of the tube 1 and has at the upper edge and on the piston head 12 each a radially projecting guide flange 14 or 15 lying airtight against the inner wall of the tube abuts the upper edge of its side wall 11 on a horizontal cover closing the tube 1 and can be filled through an inlet 18 of the cover, and a lower position in which the piston crown 12 rests on the partition 7 and the filling piston 10 in the reservoir 3 is emptied. At the lowest point of his z. B. funnel-shaped lowering bottom, the filling piston 10 has an outlet valve 20 which is automatically opened by external control when the emptying position is reached. According to the example shown, the outlet valve 20 may have a downward actuating pin 21, which is pushed upwards to open the valve by an upward projection on the top of the partition 7, whereupon the coating material by gravity from the filling piston 10 through the inlet opening 8 in the reservoir 3 can flow.

Die vertikalen Auf- und Abbewegungen des Füllkolbens werden durch pneumatischen Antrieb und Schwerkraft bewirkt und in Abhängigkeit vom Materialverbrauch und Füllstand im Vorratsbehälter 3 gesteuert. Hierfür führt in das Rohr 1 ein Drucklufteinlaß 23, der in einer Ausnehmung am oberen Seitenrand der Trennwand 7, also direkt unter der als Kolbenfläche dienenden Unterseite des auf der Trennwand 7 aufsitzenden Füllkolbens 10 mündet. Der Drucklufteinlaß 23 ist über ein Ventil 24 an eine Druckluftleitung 25 angeschlossen. Im Bereich des Vorratsbehälters 3 befinden sich an der Wand des Rohres 1 übereinander zwei Füllstandsensoren an sich bekannter Art, von denen der obere Sensor 28 anspricht, sobald das Flüssigkeitsniveau im Vorratsbehälter 3 den gewünschten Maximalstand erreicht, während der untere Sensor 29 bei Unterschreiten eines gewünschten Mindestniveaus anspricht. In dem bis auf den Füllkolben 10 leeren Bereich des Rohres 1 über der Trennwand 7 sind an der Rohrwand übereinander weitere Sensoren 30, 31 und 32 angebracht, die aus an sich bekannten Initiatoren bestehen können und bei Annäherung des Füllkolbens 10 ansprechen. Der obere Sensor 30 spricht an, wenn der Füllkolben 10 seine obere Endposition erreicht. Der etwas unterhalb vom Sensor 30 angebrachte Sensor 31 spricht an, wenn der Füllkolben 10 aus seiner oberen Endstellung etwas nach unten abgesunken ist. Der weiter unten in der Nähe der Trennwand 7 angebrachte Sensor 32 spricht an, wenn der Füllkolben auf der Trennwand 7 aufsitzt. Die Sensoren 28 bis 32 steuern (über die gestrichelt dargestellten Steuerleitungen) das Druckluftventil 24 und ein Füllventil 35, das in eine zum Einlaß 18 des Rohres 1 führende Leitung 36 des geerdeten Versorgungssystems geschaltet ist oder auch in den Einlaß 18 eingebaut sein könnte. Dem Sensor 32 kann ein Zeitglied 33 nachgeschaltet sein. Wenn im Betrieb der Vorratsbehälter 3 gefüllt ist, sitzt der Füllkolben 10 unten auf der horizontalen Trennwand 7. Sobald infolge des Materialverbrauchs der Sensor 29 ein Absinken des Füllstandes im Behälter bis zu einem Mindestniveau meldet, das nicht unterschritten werden soll, wird selbsttätig das Druckluftventil 24 geöffnet. Dadurch wird der Füllkolben 10 pneumatisch angehoben, wobei das Ventil 20 des Füllkolbens selbsttätig schließt, und bis in seine obere Endposition bewegt, in der er zunächst in Schwebe gehalten wird. Der auf diese Position ansprechende Sensor 30 öffnet das Füllventil 35, so daß der Füllkolben 10 durch die Öffnung 18 gefüllt wird. Im Deckel 17 befindet sich ferner ein Entlüftungsventil 38. Beim Füllen beginnt der Füllkolben nach kurzer Zeit durch seine zunehmende Masse abzusinken. Er ist voll, wenn er den Sensor 31 erreicht, der daraufhin das Füllventil 35 schließt und auch die Druckluft am Ventil 24 abschalten oder den Druck reduzieren kann. Der volle Füllkolben 10 sinkt wieder bis auf die Trennwand 7 und entleert sich in den Vorratsbehälter 3. Nach einer z. B. durch das Zeitglied 33 bestimmten Verzögerungszeit wiederholt sich der Vorgang, und zwar so oft, bis der Sensor 28 das Erreichen eines Maximalniveaus meldet, das nicht überschritten werden soll.The vertical up and down movements of the filling piston are effected by pneumatic drive and gravity and controlled depending on the material consumption and level in the storage container 3. For this purpose, a compressed air inlet 23 leads into the tube 1, which opens into a recess at the upper side edge of the partition 7, that is to say directly below the underside of the filling piston 10 seated on the partition 7 and serving as the piston surface. The compressed air inlet 23 is connected to a compressed air line 25 via a valve 24. In the area of the storage container 3 there are two fill level sensors of known type one above the other on the wall of the tube 1, of which the upper sensor 28 responds as soon as the liquid level in the storage container 3 reaches the desired maximum level, while the lower sensor 29 when the desired minimum level is undershot appeals. In the region of the tube 1 above the partition 7 that is empty except for the filling piston 10, further sensors 30, 31 and 32 are attached to the tube wall one above the other, which sensors may consist of initiators known per se and respond when the filling piston 10 approaches. The upper sensor 30 responds when the filling piston 10 reaches its upper end position. The sensor 31 attached somewhat below the sensor 30 responds when the filling piston 10 is somewhat out of its upper end position has sunk down. The sensor 32 attached further below in the vicinity of the partition 7 responds when the filling piston is seated on the partition 7. The sensors 28 to 32 control (via the control lines shown in dashed lines) the compressed air valve 24 and a filling valve 35 which is connected to a line 36 of the earthed supply system leading to the inlet 18 of the pipe 1 or could also be installed in the inlet 18. A timer 33 can be connected downstream of the sensor 32. When the storage container 3 is filled during operation, the filling piston 10 sits at the bottom on the horizontal partition wall 7. As soon as the sensor 29 reports a drop in the filling level in the container to a minimum level which should not be undercut due to the material consumption, the compressed air valve 24 becomes automatic open. As a result, the filling piston 10 is lifted pneumatically, the valve 20 of the filling piston automatically closing and moving into its upper end position, in which it is initially held in suspension. The sensor 30 responsive to this position opens the filling valve 35 so that the filling piston 10 is filled through the opening 18. In the cover 17 there is also a vent valve 38. When filling, the filling piston begins to drop after a short time due to its increasing mass. It is full when it reaches the sensor 31, which then closes the filling valve 35 and can also switch off the compressed air at the valve 24 or reduce the pressure. The full filling piston 10 drops again to the partition 7 and empties into the reservoir 3. After a z. B. by the timer 33 determined delay time, the process is repeated until the sensor 28 reports reaching a maximum level that should not be exceeded.

Es ist zweckmäßig, den im druckfesten, vollständig verschließbaren Rohr 1 erzeugten Druck zum Entleeren des Vorratsbehälters 3 zu nutzen. Dadurch erübrigt es sich, dem Vorratsbehälter zum Entleeren eine eigens hierfür vorgesehene Förderpumpe od. dgl. nachzuschalten.It is expedient to use the pressure generated in the pressure-tight, completely closable tube 1 for emptying the storage container 3. This makes it unnecessary to connect a storage pump or the like specially provided for emptying the storage container.

Der Vorratsbehälter 3 kann pausenlos auch während der oben beschriebenen Füllvorgänge entleert werden und mit seinem Inhalt ständig auf dem Hochspannungspotential der Sprühvorrichtung bleiben, mit der er über das leitende Beschichtungsmaterial in der Leitung 5 verbunden ist. Durch den Abstand des erwähnten maximalen Füllniveaus im Behälter 3 von dem geerdeten Versorgungssystem an der Oberseite des Rohres 1, der ausreichend größer bemessen ist als die Überschlagweite der Hochspannung, sind die auf unterschiedlichen Potentialen liegenden Teile der Anlage ständig voneinander isoliert.The storage container 3 can be emptied non-stop even during the filling processes described above and its contents remain constantly at the high-voltage potential of the spraying device to which it is connected via the conductive coating material in the line 5. Due to the distance of the above-mentioned maximum filling level in the container 3 from the grounded supply system on the top of the tube 1, which is dimensioned sufficiently larger than the flashover distance of the high voltage, the parts of the system which are at different potentials are constantly isolated from one another.

Die beschriebene Anordnung erfordert wenig Bauaufwand und läßt sich kompakt und raumsparend realisieren, was besonders im Fall einer großen Anzahl auswählbarer Beschichtungsmaterialien unterschiedlicher Farbe von Interesse ist, für die je eine isolierende Behälteranordnung der beschriebenen Art benötigt wird. In praktischen Anwendungsfällen kann ein relativ kleiner Füllkolben für einen Inhalt von etwa 1 l und ein entsprechend bemessenes Rohr 1 mit einem Durchmesser von etwa 15 cm ausreichend sein. Die den verschiedenen Farben entsprechenden Rohre 1 können in einer gemeinsamen Einheit zusammengebaut werden.The arrangement described requires little construction effort and can be realized in a compact and space-saving manner, which is of particular interest in the case of a large number of selectable coating materials of different colors, for each of which an insulating container arrangement of the type described is required. In practical applications, a relatively small filling piston for a content of approximately 1 l and a correspondingly dimensioned tube 1 with a diameter of approximately 15 cm may be sufficient. The tubes 1 corresponding to the different colors can be assembled in a common unit.

Da man beim Füllen und Entleeren des Zwischenbehälters der beschriebenen Anlage unabhängig vom jeweiligen Betriebszustand der Beschichtungsvorrichtung und nicht auf Beschichtungspausen angewiesen ist, kann man auch eine einzige gemeinsame Zwischen- und Vorratsbehälteranordnung (pro Farbe) beispielsweise für alle "Ebenen" aus jeweils mehreren Zerstäubern in einer Sprühkabine verwenden.Because when filling and emptying the intermediate container of the system described, regardless of the respective operating state the coating device and not relying on coating breaks, one can also use a single common intermediate and storage container arrangement (per color), for example for all "levels" of several atomizers in a spray booth.

Claims (9)

  1. Coating installation for serially coating workpieces with electrically conductive coating material including a supply system (36) at low potential or earth potential, a coating device subjected, in operation, to high voltage and an intermediate container (10), which is movable up and down between two positions, to which the coating material is supplied from an outlet of the supply system (36) in a first position and which, in its second position, in which its contents are electrically insulated from the outlet of the supply system (36), discharges the coating material into a storage container (3) connected to the coating device, characterised in that the intermediate container (10), which is movable up and down, is supported in a closed tube (1) and constructed as a filling piston (10) which may be raised by a pressure medium introduced into the tube (1).
  2. Installation as claimed in claim 1, characterised in that the pressure medium is compressed air which is introduced into the tube (1) through an inlet (23) opening out below the underside of the filling piston (10), when it is situated in its lower end position.
  3. Installation as claimed in claim 1 or 2, characterised in that the storage container (3) is situated in a portion of the tube (1) containing the filling piston (10) coaxially with the filling piston below a horizontal partition wall (7) on which the filling piston (10) rests in its lower end position and which includes an opening (8) for the coating material.
  4. Installation as claimed in claim 3, characterised in that situated in the base of the filling piston (10) there is an outlet valve (20) which automatically opens into the opening (8) when the filling piston (10) rests on the partition wall.
  5. Installation as claimed in claim 3 or 4, characterised in that arranged on the wall of the tube (1) there are sensors (28,32) which respond to maximum and/or minimum filling levels of the coating material in the storage container (3) and/or to the vertical position of the filling piston (10).
  6. Installation as claimed in claim 5, characterised in that mounted on the storage container (3) there is a respective sensor (28,29) for maximum and minimum filling levels and, at the upper end of the tube (1), two sensors (30,31), of which the one sensor (30) responds when the filling piston (10) reaches the upper end position whilst the other sensor (31) responds when the filling piston (10) has descended from its upper end position by an amount which is substantially smaller than its total stroke.
  7. Installation as claimed in claim 5 or 6, characterised in that the sensors (28 to 32) control a compressed air valve (24), which is provided upstream of the compressed air inlet (24), and/or a filling valve (35) of the supply system upstream of the material inlet (18) of the tube (1).
  8. Installation as claimed in one of the preceding claims, characterised in that the filling piston (10) is an upwardly open cylindrical container and the tube (1) is closed at the upper end by a lid (17) with an inlet (18) for filling the filling piston (10).
  9. Installation as claimed in one of the preceding claims, characterised in that the storage container (3) is of air-tight construction and may be emptied by subjecting the container to pressure.
EP91106543A 1990-04-30 1991-04-23 Plant for coating series of work pieces with conductive coating material Expired - Lifetime EP0455110B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE4013942 1990-04-30
DE4013942A DE4013942A1 (en) 1990-04-30 1990-04-30 PLANT FOR SERIES COATING OF WORKPIECES WITH CONDUCTIVE COATING MATERIAL

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EP0455110A1 EP0455110A1 (en) 1991-11-06
EP0455110B1 true EP0455110B1 (en) 1993-12-15

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GB2282085A (en) * 1993-08-18 1995-03-29 John Stephen Griffiths Paint supply apparatus
US5364035A (en) * 1993-12-20 1994-11-15 Graco Inc. High voltage sealing and isolation via dynamic seals
DE4444671A1 (en) * 1994-12-15 1996-06-20 Abb Patent Gmbh Paint feed pump
DE19610589A1 (en) * 1996-03-18 1997-09-25 Duerr Gmbh & Co Process and system for supplying paint to a coating system
ES2717116T3 (en) 2005-10-07 2019-06-19 Duerr Systems Ag Coating agent supply device and corresponding operating procedure
US8020784B2 (en) 2005-10-07 2011-09-20 Durr Systems Inc. Coating material supply installation and associated operating procedure
CN108043648B (en) * 2018-01-30 2019-01-11 嘉兴敏惠汽车零部件有限公司 A kind of environmental protection spray-painting plant
CN108043629A (en) * 2018-01-30 2018-05-18 浙江夏远信息技术有限公司 A kind of environmental protection paint spraying apparatus
CN108043636A (en) * 2018-01-30 2018-05-18 浙江夏远信息技术有限公司 A kind of Environmental Safety spray-painting plant

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NL187613C (en) * 1978-01-11 1991-12-02 Akzo Nv DEVICE FOR ELECTROSTATIC SPRAYING OF ELECTRICALLY CONDUCTIVE PAINT.
US4232055A (en) * 1979-04-24 1980-11-04 Champion Spark Plug Company Automatic color change electrostatic paint spray system
US4287756A (en) * 1979-10-24 1981-09-08 Gallagher John J Stratified fluid interface recorder
GB8412460D0 (en) * 1984-05-16 1984-06-20 Schlumberger Electronics Uk Fluid level measurement
DE3440381A1 (en) * 1984-11-05 1986-05-07 Ransburg Gmbh, 6056 Heusenstamm METHOD AND DEVICE FOR AUTOMATIC ELECTROSTATIC SPRAY COATING
DE3717929A1 (en) * 1987-05-27 1988-12-08 Behr Industrieanlagen Process and system for electrostatic coating with conductive material
DE3725172A1 (en) * 1987-05-27 1989-02-09 Behr Industrieanlagen METHOD AND SYSTEM FOR ELECTROSTATIC COATING WITH CONDUCTIVE MATERIAL

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Publication number Publication date
DE59100712D1 (en) 1994-01-27
EP0455110A1 (en) 1991-11-06
DE4013942A1 (en) 1991-10-31

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