EP1104334B1 - Powder spray coating device - Google Patents

Powder spray coating device Download PDF

Info

Publication number
EP1104334B1
EP1104334B1 EP99927926A EP99927926A EP1104334B1 EP 1104334 B1 EP1104334 B1 EP 1104334B1 EP 99927926 A EP99927926 A EP 99927926A EP 99927926 A EP99927926 A EP 99927926A EP 1104334 B1 EP1104334 B1 EP 1104334B1
Authority
EP
European Patent Office
Prior art keywords
air
powder
control system
conveying
restrictor
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP99927926A
Other languages
German (de)
French (fr)
Other versions
EP1104334A1 (en
Inventor
Felix Mauchle
Gerald Haas
Hans Peter Michael
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.)
Gema Switzerland GmbH
Original Assignee
Gema Switzerland GmbH
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Gema Switzerland GmbH filed Critical Gema Switzerland GmbH
Publication of EP1104334A1 publication Critical patent/EP1104334A1/en
Application granted granted Critical
Publication of EP1104334B1 publication Critical patent/EP1104334B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
    • B05B7/00—Spraying apparatus for discharge of liquids or other fluent materials from two or more sources, e.g. of liquid and air, of powder and gas
    • B05B7/14—Spraying apparatus for discharge of liquids or other fluent materials from two or more sources, e.g. of liquid and air, of powder and gas designed for spraying particulate materials
    • B05B7/1404—Arrangements for supplying particulate material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
    • B05B7/00—Spraying apparatus for discharge of liquids or other fluent materials from two or more sources, e.g. of liquid and air, of powder and gas
    • B05B7/14—Spraying apparatus for discharge of liquids or other fluent materials from two or more sources, e.g. of liquid and air, of powder and gas designed for spraying particulate materials
    • B05B7/1404—Arrangements for supplying particulate material
    • B05B7/1472—Powder extracted from a powder container in a direction substantially opposite to gravity by a suction device dipped into the powder

Definitions

  • the invention relates to a powder spray coating device according to the preamble of claim 1.
  • Such a powder spray coating device is from the EP-A-0 686 430 is known.
  • a powder conveying device is included an electronic control device known in Dependence on a setpoint for the per unit time conveying powder quantity and a target value for the pro Total amount of air to be promoted, which for the Conveying the powder is necessary for manipulated variable signals Pressure regulator generated, which depending on the Supply of conveying air and additional air to an injector regulate.
  • the control signals of the control device are from the controllers as setpoints and depending on an actual value of the conveying air or the additional air for control this conveying air or the additional air used. Instead of Flow controllers can be used for pressure regulators.
  • US-A-5 186 388 it is known to use the negative pressure in the To measure the negative pressure range of an injector and as a measure for to use the amount of powder conveyed per unit of time.
  • US-A-4 544 306 it is known to provide a measuring tube which has one end open to the atmosphere and one in one Powder air duct open end for measuring the inside prevailing pressure.
  • a valve becomes on the powder discharge outlet opened or closed, which is on the funnel-shaped lower end of a powder tank truck.
  • US-A-3 625 404 and DE-A-44 09 493 are air dividers known which a throttle valve in a Conveying air line and a throttle valve in one Auxiliary air line included, which mechanically with each other are coupled. To the same extent that one is opened, the other is closed.
  • the object of the invention is to be achieved in Dependence on a manually or automatically specified Setpoint for the amount of powder to be conveyed per unit of time precise and stable regulation of the pneumatically conveyed To achieve powder flow without expensive pressure regulators or volume flow controller are required.
  • the invention makes it structurally simple and inexpensive device created, which an automatic and enables precise control of a powder-air flow, which is stable from start to shutdown, enables pulsation-free powder-air flow.
  • Value terms used in the description such as Setpoint, actual value and / or manipulated variable have depending on the desired design of the device the importance of a Value point or a value range. But also with one Value point there are still tolerance-dependent fluctuations in value within the invention.
  • the Compressed air source 12 is via a compressed air line 20 connected in terms of flow to the injector nozzle 6.
  • the Compressed air line 20 contains a variable throttle 18, the Flow resistance (e.g. flow cross section) through a drive connected to her servomotor 19 in Dependence on a setpoint for that per unit of time delivered volume of conveying air and / or from a setpoint for the amount of powder delivered per unit of time electronic control device 21 is controllable.
  • the downstream end portion 22 of the Powder-air channel 2 can be designed as an atomizing nozzle or over a hose with a sprayer for spraying of the powder onto an object to be coated his.
  • the powder suction channel 8 extends through an immersion tube 24, which is vertically in the powder 16 of the powder container 14th is immersed.
  • An upper end portion 26 of the Powder suction channel 8 has relative to the upstream Channel section an expanded flow cross-section, which is connected to the vacuum chamber 10 and together with this forms a vacuum area, in which the conveying air jet 7 of the injector 6 a generates essentially homogeneous vacuum or vacuum.
  • the vacuum generated by the conveying air jet 7 extends but with different strength throughout Powder suction channel through.
  • the vacuum region 10, 26 is with the outside atmosphere 32 through a measuring channel 30 fluidly connected or connectable, which with a adjustable flow throttle 34 is provided.
  • the one in Vacuum area 10, 26 prevailing vacuum or vacuum sucks through the measuring channel 30 throttled through the Flow throttle 34 air from the outside atmosphere 32.
  • the Measuring channel 30 is provided with a measuring device 36 which depending on the through the measuring channel 30 of the Outside atmosphere 32 flowing in the vacuum region 10, 26 Air on a signal line 38 generates a measurement signal, which is a measure of the measurement channel 30 per unit time flowing air and thus also a measure of the through the Powder-air channel 2 amount of powder conveyed per unit of time is.
  • the measurement signal can be an electrical, pneumatic or hydraulic signal and accordingly can be Signal line 38 an electrical, pneumatic or be hydraulic line, which with the control device 21st is functionally connected.
  • the downstream end 42 of the Measuring channel 30 is preferably connected to vacuum chamber 10 connected in terms of flow.
  • it is at the downstream end portion 26 of the Powder suction channel 8 connected in terms of flow, wherein this end section has such a large cross section that in essentially the same negative pressure or the same Vacuum prevails as in the vacuum chamber 10, so that this End portion 26 viewed as part of the vacuum chamber 10 can be.
  • the measuring device 36 is preferably a flow meter, which, depending on the per unit time by the Measuring channel 30 flowing outside air volume generates the measurement signal.
  • the measuring device is 36 a pressure drop measuring device which, depending on a pressure drop of the flowing through the measuring channel 30 Outside air generates the measurement signal on the signal line 38.
  • to Measurement of the pressure drop only needs at one measuring point downstream of the flow restrictor 34 the air pressure in Measuring channel 30 to be measured, since this with the pressure of the Outside air in relation to an outside atmosphere inlet 32 in relation can be set. If the measuring channel 30 a capillary has a narrow cross-section, no additional Flow restrictor 34 required.
  • Flow cross section by a drive with it connected actuator 45 from the electronic Control device 21 is controlled depending on one Setpoint for the volume delivered per unit of time Additional air, which in turn depends on the setpoint for the powder rate and / or from the setpoint for the Conveyor air rate.
  • Additional compressed air is passed into the vacuum region 10, 26 are used to influence the negative pressure.
  • the vacuum prevailing in the vacuum chamber 10 or Vacuum is not absolutely constant and fluctuates itself then when the delivery air rate of the injector nozzle 6 and the Auxiliary air rate in the auxiliary air inlet 46 as well Powder level 48 kept constant in the powder container 14 become.
  • Such uncontrolled fluctuations in negative pressure in the vacuum chamber 10 also undesirably lead to fluctuations in the amount of powder conveyed per unit of time in the powder-air channel 2.
  • a compensating air inlet 56 e.g. in the form of a second injector nozzle, which with small distance from the upstream beginning 58 of the Powder outlet channel 8 is arranged axially and through a second vacuum chamber 60 formed therebetween Compensating air blows axially into the powder suction channel 8.
  • the Compensating air is supplied by the second atomizer nozzle Compressed air source 12 via a third variable flow restrictor 62 in a compressed air line 64 and via a Compensation air channel 66 supplied.
  • the powder suction channel 8 and the compensation air channel 66 are axially parallel in the Dip tube 24, in the lower end portion of which the second Injector nozzle 56 is arranged.
  • the powder inlet for the Powder suction channel 8 is through one or more Powder inlet openings 68 formed, which across the Dip tube 24 through the dip tube outer surface 70 and thus the powder 16 located in the powder container 14 with the second vacuum chamber 60 of the second injector 72 connect in terms of flow.
  • the flow resistance (e.g. the Flow cross section) of the third variable throttle 62 can fixed or manual or preferably by a drivingly connected to it servomotor 63 from the Control device 21 depending on other criteria (Powder rate, conveying air rate and / or additional air rate) are automatically set or regulated.
  • the control device 21 controls depending on the Measuring signal of the measuring line 38 and depending on the Setpoint or the setpoints of the different types of compressed air via the throttles 18, 44 and 62 the supply of the conveying air, the additional air and / or the balancing air.
  • the powder container 14 is preferably designed such that the powder 16 contained in it hovers in an air stream, whose air through a perforated container bottom 74 in the Inside the container flows.
  • From the balance air inlet 56 is a much smaller amount of air per unit time in the Powder stream introduced as with the first injector 6.
  • the compensation air of the compensation inlet 56 can however does not need in the second vacuum chamber 60 Aspirate powder from powder container 14.
  • the balancing air is through this inlet 56 with a small constant Quantity supplied per unit of time and therefore has a stabilizing effect on those described above Pressure fluctuations in the powder intake duct 8.
  • the compensation air of the balance air inlet 56 makes the above Fluctuations of high frequency (shorter and faster) and smaller in amplitude. This will make the Controller setting times of the control device 21 which is trying to compensate for the fluctuations mentioned, much shorter. In trials, the standard setting times could be reduced to a third be shortened.
  • the electronic control device 21 preferably contains one or more microcomputers with computer programs in the hardware or software for executing the described Method.
  • the control device 21 has a powder setpoint input 80 for manual or automatic entry of a fixed or variable setpoint for the to be funded per unit of time Amount of powder "m", for example in grams / hour (g / h); one Total air setpoint input 81 for manual or automatic entry of a fixed or variable setpoint for the total air "GV" through the powder-air channel 2 too total air flow (air volume flow) consisting of Conveying air of the conveying air line 20, the additional air of the Auxiliary air line 43 and the compensation air Compensating air line 64; a high voltage setpoint input 82 for manual or automatic entry of a High voltage value for a high voltage for electrostatic charging of the powder to be sprayed; and possibly a setpoint input 83 for the pro Unit of time supplied equalizing air volume "AV" of the Compensation air inlet 56.
  • a powder setpoint input 80 for manual or automatic entry of a fixed or variable setpoint for the to be funded per unit of time Amount of powder "m", for example in grams / hour (g
  • the powder to be sprayed can electrostatically by electrodes in a known manner to be charged.
  • the amount of balancing air of the Compensating air inlet 56 can, but often does not need, considered in the function of the control device 21 because their amount is much smaller than the amount Conveying air.
  • the balance air of the balance air inlet 56 can be set to a fixed value or according to the Invention via an adjustable throttle 62 of its own Servomotor 63 are controlled by the control device 21 in Dependence on other values, for example the powder setpoint "m" and / or one of the air setpoints.
  • control device 21 is in the form of stored Data or data programs stored, how much conveying air and how much additional air via the conveying air line 20 and over the additional air line 43 to the injector when setting of a specific powder setpoint "m" are to be supplied under Compliance with the target value for the total air volume "GV".
  • Fig. 1 in the Control device 21 drawn a diagram, which shows that for any set powder setpoint "m” depending on the given Total air volume setpoint "GV” is a specific setpoint for the conveying air results in "FV”.
  • the control device 21 generates depending on your specified target values and these actual values Control signals on the electrical lines 85, 86 and / or 87 of the servomotors 19, 45 and / or 63.
  • the amount of powder delivered per unit of time (powder rate) is roughly proportional to the amount funded per unit of time Conveying air quantity of the conveying air line 20. Therefore needs just the conveying air to be adjusted to a set the desired amount of powder.
  • the control device 21 then automatically sets the additional air rate through the Actuator 45 and the throttle 44 so that despite the changed Delivery air rate of the total air volume flow (total air rate) remains at the setpoint.
  • the non-linear dependency for at least one or more flow resistances stored diagrammatically in such a way that the control device 21 the chokes 18 and 44 by the servomotors 19 and 45 in Controlling dependency on setpoint values non-linearly, that there is a linear change in the setpoint change in the Delivery air rate and / or the additional air rate results.

Landscapes

  • Nozzles (AREA)
  • Electrostatic Spraying Apparatus (AREA)
  • Air Transport Of Granular Materials (AREA)
  • Manufacturing Of Micro-Capsules (AREA)

Abstract

A spray powder-coating apparatus fitted with an electronic control system (21) regulating the air flows (20, 43) to an injector (4) as a function of setpoints (m) for the rates of powder to be moved, and as a function of a setpoint (GV) for the total rate of air passing through the nozzle, by means of motor-driven adjustable throttles (18, 19, 44, 45), preferably also as a function of the actual values (89, 90) of the regulated air flows (20, 43).

Description

Die Erfindung betrifft eine Pulver-Sprühbeschichtungsvorrichtung gemäß dem Oberbegriff von Anspruch 1.The invention relates to a powder spray coating device according to the preamble of claim 1.

Eine solche Pulver-Sprühbeschichtungsvorrichtung ist aus der EP-A-0 686 430 bekannt.Such a powder spray coating device is from the EP-A-0 686 430 is known.

Aus der EP-A-0 636 420 ist eine Pulverförder-Vorrichtung mit einer elektronischen Regelvorrichtung bekannt, welche in Abhängigkeit von einem Sollwert für die pro Zeiteinheit zu fördernde Pulvermenge und einem Sollwert für die pro Zeiteinheit zu fördernde Gesamtluftmenge, welche für die Förderung des Pulvers erforderlich ist, Stellwert-Signale für Druckregler erzeugt, welche in Abhängigkeit hiervon die Zufuhr von Förderluft und von Zusatzluft zu einem Injektor regeln. Die Stellwert-Signale der Regelvorrichtung werden von den Reglern als Sollwerte betrachtet und in Abhängigkeit von einem Istwert der Förderluft bzw. der Zusatzluft zur Regelung dieser Förderluft bzw. der Zusatzluft verwendet. Anstelle von Druckreglern können Volumenstromregler verwendet werden.From EP-A-0 636 420 a powder conveying device is included an electronic control device known in Dependence on a setpoint for the per unit time conveying powder quantity and a target value for the pro Total amount of air to be promoted, which for the Conveying the powder is necessary for manipulated variable signals Pressure regulator generated, which depending on the Supply of conveying air and additional air to an injector regulate. The control signals of the control device are from the controllers as setpoints and depending on an actual value of the conveying air or the additional air for control this conveying air or the additional air used. Instead of Flow controllers can be used for pressure regulators.

Aus der US-A-4 747 731 (korrespondiert zu EP-A-0 239 331 und 0 423 850) ist eine pneumatische Pulver-Fördervorrichtung bekannt, bei welcher 2 Injektoren vorgesehen sind, von welchen sich der Haupt-Injektor am stromabwärtigen Ende und ein Hilfs-Injektor am stromaufwärtigen Ende eines Pulveransaugrohres befindet.From US-A-4 747 731 (corresponds to EP-A-0 239 331 and 0 423 850) is a pneumatic powder conveyor known in which 2 injectors are provided by which is the main injector at the downstream end and an auxiliary injector at the upstream end of a Powder suction pipe is located.

Aus der US-A-5 186 388 ist es bekannt, den Unterdruck in dem Unterdruckbereich eines Injektors zu messen und als Maß für die pro Zeiteinheit geförderte Pulvermenge zu verwenden. Aus der US-A-4 544 306 ist es bekannt, ein Meßrohr vorzusehen, welches ein zur Atmosphäre offenes Ende und ein in einem Pulver-Luft-Kanal offenes Ende zur Messung des darin herrschenden Druckes aufweist. In Abhängigkeit von dem Druck, welcher von der Pulver-Luft-Strömung erzeugt wird, relativ zum Atmosphärendruck, wird ein Ventil am Pulverabgabe-Auslaß geöffnet oder geschlossen, welches sich am trichterförmigen unteren Ende eines Pulver-Tankwagens befindet.From US-A-5 186 388 it is known to use the negative pressure in the To measure the negative pressure range of an injector and as a measure for to use the amount of powder conveyed per unit of time. Out US-A-4 544 306 it is known to provide a measuring tube which has one end open to the atmosphere and one in one Powder air duct open end for measuring the inside prevailing pressure. Depending on the pressure, which is generated by the powder-air flow, relative to atmospheric pressure, a valve becomes on the powder discharge outlet opened or closed, which is on the funnel-shaped lower end of a powder tank truck.

Aus der US-A-3 625 404 und der DE-A-44 09 493 sind Luft-Teiler bekannt, welche ein Drosselventil in einer Förderluftleitung und ein Drosselventil in einer Zusatzluftleitung enthalten, welche mechanisch miteinander gekoppelt sind. In gleichem Maße, wie das eine geöffnet wird, wird das andere geschlossen.US-A-3 625 404 and DE-A-44 09 493 are air dividers known which a throttle valve in a Conveying air line and a throttle valve in one Auxiliary air line included, which mechanically with each other are coupled. To the same extent that one is opened, the other is closed.

Durch die Erfindung soll die Aufgabe gelöst werden, in Abhängigkeit von einem manuell oder automatisch vorgebbaren Sollwert für die pro Zeiteinheit zu fördernde Pulvermenge eine genaue und stabile Regelung des pneumatisch geförderten Pulverstromes zu erzielen, ohne daß dafür teure Druckregler oder Volumenstromregler erforderlich sind.The object of the invention is to be achieved in Dependence on a manually or automatically specified Setpoint for the amount of powder to be conveyed per unit of time precise and stable regulation of the pneumatically conveyed To achieve powder flow without expensive pressure regulators or volume flow controller are required.

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

Durch die Erfindung wird eine konstruktiv einfache und preiswerte Einrichtung geschaffen, welche eine automatische und genaue Regelung eines Pulver-Luft-Stromes ermöglicht, welcher vom Start bis zum Abschalten eine stabile, pulsationsfreie Pulver-Luft-Strömung ermöglicht.The invention makes it structurally simple and inexpensive device created, which an automatic and enables precise control of a powder-air flow, which is stable from start to shutdown, enables pulsation-free powder-air flow.

Im Rahmen der Beschreibung verwendete Werte-Begriffe wie Sollwert, Istwert und/oder Stellwert haben je nach dem gewünschten Design der Vorrichtung die Bedeutung eines Wertepunktes oder eines Wertebereiches. Aber auch bei einem Werte-Punkt liegen toleranzabhängige Werteschwankungen noch innerhalb der Erfindung.Value terms used in the description such as Setpoint, actual value and / or manipulated variable have depending on the desired design of the device the importance of a Value point or a value range. But also with one Value point there are still tolerance-dependent fluctuations in value within the invention.

Die Erfindung wird im folgenden mit Bezug auf die Zeichnung anhand einer bevorzugten Ausführungsform als Beispiel beschrieben. Die Zeichnung zeigt in

Fig. 1
eine Pulver-Sprühbeschichtungsvorrichtung nach der Erfindung mit einem Injektor im Axialschnitt und einem Pulveransaugrohr im Vertikalschnitt.
The invention is described below with reference to the drawing using a preferred embodiment as an example. The drawing shows in
Fig. 1
a powder spray coating device according to the invention with an injector in axial section and a powder suction pipe in vertical section.

Die in Fig. 1 dargestellte Pulver-Sprühbeschichtungs-Vorrichtung nach der Erfindung enthält einen Pulver-Luft-Kanal 2, einen Injektor 4 als Fluidförderer, welcher eine im wesentlichen axial in den Pulver-Luft-Kanal 2 gerichtete Injektordüse 6 aufweist, und einen Pulveransaugkanal 8, welcher an eine Unterdruckkammer 10 des Injektors 4 strömungsmäßig angeschlossen ist. Die Unterdruckkammer 10 befindet sich zwischen der Injektordüse 6 und dem Pulver-Luft-Kanal 2. Ein von der Injektordüse 6 in den Pulver-Luft-Kanal 2 getriebener Förderluftstrahl 7 einer Druckluftquelle 12 saugt aus einem Pulverbehälter 14 Pulver 16 durch den Pulveransaugkanal 8 in die Unterdruckkammer 10, in welcher sich das Pulver mit dem Förderluftstrahl vermischt und dann zusammen mit ihm durch den Pulver-Luft-Kanal 2 strömt. Die Druckluftquelle 12 ist über eine Druckluftleitung 20 strömungsmäßig an die Injektordüse 6 angeschlossen. Die Druckluftleitung 20 enthält eine variable Drossel 18, deren Strömungswiderstand (z.B. Strömungsquerschnitt) durch einen antriebsmäßig mit ihr verbundenen Stellmotor 19 in Abhängigkeit von einem Sollwert für das pro Zeiteinheit geförderte Volumen an Förderluft und/oder von einem Sollwert für die pro Zeiteinheit geförderte Menge Pulver von einer elektronischen Regelvorrichtung 21 regelbar ist.The powder spray coating device shown in FIG. 1 according to the invention contains a powder-air channel 2, an injector 4 as a fluid conveyor, which one in essentially axially directed into the powder-air channel 2 Injector nozzle 6, and a powder suction channel 8, which to a vacuum chamber 10 of the injector 4th is connected in terms of flow. The vacuum chamber 10 is located between the injector nozzle 6 and the powder-air channel 2. One from the injector nozzle 6 into the powder-air channel 2 driven conveyor air jet 7 of a compressed air source 12 sucks powder 16 from a powder container 14 through the Powder suction channel 8 in the vacuum chamber 10, in which the powder mixes with the conveying air jet and then flows together with him through the powder-air channel 2. The Compressed air source 12 is via a compressed air line 20 connected in terms of flow to the injector nozzle 6. The Compressed air line 20 contains a variable throttle 18, the Flow resistance (e.g. flow cross section) through a drive connected to her servomotor 19 in Dependence on a setpoint for that per unit of time delivered volume of conveying air and / or from a setpoint for the amount of powder delivered per unit of time electronic control device 21 is controllable.

Der in Fig. 1 dargestellte stromabwärtige Endteil 22 des Pulver-Luft-Kanals 2 kann als Zerstäuberdüse ausgebildet oder über einen Schlauch mit einer Sprühvorrichtung zum Sprühen des Pulvers auf einen zu beschichtenden Gegenstand versehen sein.The downstream end portion 22 of the Powder-air channel 2 can be designed as an atomizing nozzle or over a hose with a sprayer for spraying of the powder onto an object to be coated his.

Der Pulveransaugkanal 8 erstreckt sich durch ein Tauchrohr 24, welches vertikal in das Pulver 16 des Pulverbehälters 14 eingetaucht ist. Ein oberer Endabschnitt 26 des Pulveransaugkanals 8 hat relativ zum stromaufwärtigen Kanalabschnitt einen erweiterten Strömungsquerschnitt, welcher an die Unterdruckkammer 10 angeschlossen ist und zusammen mit diesem einen Unterdruckbereich bildet, in welchem der Förderluftstrahl 7 der Injektordüse 6 einen im wesentlichen homogenen Unterdruck oder Vakuum erzeugt. Der vom Förderluftstrahl 7 erzeugte Unterdruck erstreckt sich jedoch mit unterschiedlicher Stärke durch den gesamten Pulveransaugkanal hindurch. Der Unterdruckbereich 10, 26 ist mit der Außenatmosphäre 32 durch einen Meßkanal 30 strömungsmäßig verbunden oder verbindbar, welcher mit einer einstellbaren Strömungsdrossel 34 versehen ist. Der im Unterdruckbereich 10, 26 herrschende Unterdruck oder Vakuum saugt über den Meßkanal 30 stark gedrosselt durch die Strömungsdrossel 34 Luft aus der Außenatmosphäre 32 an. Der Meßkanal 30 ist mit einer Meßvorrichtung 36 versehen, welche in Abhängigkeit von der durch den Meßkanal 30 von der Außenatmosphäre 32 in den Unterdruckbereich 10, 26 strömenden Luft auf einer Signalleitung 38 ein Meßsignal erzeugt, welches ein Maß für die durch den Meßkanal 30 pro Zeiteinheit strömende Luft und damit auch ein Maß für die durch den Pulver-Luft-Kanal 2 pro Zeiteinheit geförderte Pulvermenge ist. Das Meßsignal kann ein elektrisches, pneumatisches oder hydraulisches Signal sein und entsprechend kann auch seine Signalleitung 38 eine elektrische, pneumatische oder hydraulische Leitung sein, welche mit der Regeleinrichtung 21 funktionsmäßig verbunden ist. Das stromabwärtige Ende 42 des Meßkanals 30 ist vorzugsweise an die Unterdruckkammer 10 strömungsmäßig angeschlossen. Bei der Ausführungsform nach Fig. 1 ist es an den stromabwärtigen Endabschnitt 26 des Pulveransaugkanals 8 strömungsmäßig angeschlossen, wobei dieser Endabschnitt einen so großen Querschnitt hat, daß in ihm im wesentlichen der gleiche Unterdruck oder das gleiche Vakuum herrscht wie in der Unterdruckkammer 10, so daß dieser Endabschnitt 26 als Teil der Unterdruckkammer 10 angesehen werden kann.The powder suction channel 8 extends through an immersion tube 24, which is vertically in the powder 16 of the powder container 14th is immersed. An upper end portion 26 of the Powder suction channel 8 has relative to the upstream Channel section an expanded flow cross-section, which is connected to the vacuum chamber 10 and together with this forms a vacuum area, in which the conveying air jet 7 of the injector 6 a generates essentially homogeneous vacuum or vacuum. The vacuum generated by the conveying air jet 7 extends but with different strength throughout Powder suction channel through. The vacuum region 10, 26 is with the outside atmosphere 32 through a measuring channel 30 fluidly connected or connectable, which with a adjustable flow throttle 34 is provided. The one in Vacuum area 10, 26 prevailing vacuum or vacuum sucks through the measuring channel 30 throttled through the Flow throttle 34 air from the outside atmosphere 32. The Measuring channel 30 is provided with a measuring device 36 which depending on the through the measuring channel 30 of the Outside atmosphere 32 flowing in the vacuum region 10, 26 Air on a signal line 38 generates a measurement signal, which is a measure of the measurement channel 30 per unit time flowing air and thus also a measure of the through the Powder-air channel 2 amount of powder conveyed per unit of time is. The measurement signal can be an electrical, pneumatic or hydraulic signal and accordingly can be Signal line 38 an electrical, pneumatic or be hydraulic line, which with the control device 21st is functionally connected. The downstream end 42 of the Measuring channel 30 is preferably connected to vacuum chamber 10 connected in terms of flow. In the embodiment according to Fig. 1 it is at the downstream end portion 26 of the Powder suction channel 8 connected in terms of flow, wherein this end section has such a large cross section that in essentially the same negative pressure or the same Vacuum prevails as in the vacuum chamber 10, so that this End portion 26 viewed as part of the vacuum chamber 10 can be.

Die Meßvorrichtung 36 ist vorzugsweise ein Strömungsmeßgerät, welches in Abhängigkeit von der pro Zeiteinheit durch den Meßkanal 30 strömenden Außenluftmenge das Meßsignal erzeugt. Gemäß einer anderen Ausführungsform ist die Meßvorrichtung 36 eine Druckabfall-Meßvorrichtung, welche in Abhängigkeit von einem Druckabfall der durch den Meßkanal 30 strömenden Außenluft das Meßsignal auf der Signalleitung 38 erzeugt. Zur Messung des Druckabfalles braucht nur an einer Meßstelle stromabwärts der Strömungsdrossel 34 der Luftdruck im Meßkanal 30 gemessen zu werden, da dieser mit dem Druck der Außenluft an einem Außenatmosphären-Einlaß 32 in Relation gesetzt werden kann. Wenn der Meßkanal 30 einen kapillarartig engen Querschnitt hat, wird keine zusätzliche Strömungsdrossel 34 benötigt. In diesem Falle kann in gleicher Weise im Meßkanal 30 stromabwärts seines Außenatmosphären-Einlasses 32 ein Druckabfall relativ zum Druck der Außenatmosphäre gemessen werden. Für die Funktion des Meßkanals 30 ist es lediglich erforderlich, daß die Außenatmosphäre gedrosselt mit der Unterdruckkammer 10 in Strömungsverbindung steht, damit der Unterdruck in der Unterdruckkammer 10 durch die Außenatmosphäre nicht nachteilig reduziert oder beeinflußt wird.The measuring device 36 is preferably a flow meter, which, depending on the per unit time by the Measuring channel 30 flowing outside air volume generates the measurement signal. According to another embodiment, the measuring device is 36 a pressure drop measuring device which, depending on a pressure drop of the flowing through the measuring channel 30 Outside air generates the measurement signal on the signal line 38. to Measurement of the pressure drop only needs at one measuring point downstream of the flow restrictor 34 the air pressure in Measuring channel 30 to be measured, since this with the pressure of the Outside air in relation to an outside atmosphere inlet 32 in relation can be set. If the measuring channel 30 a capillary has a narrow cross-section, no additional Flow restrictor 34 required. In this case, same way in the measuring channel 30 downstream of it Outside atmosphere inlet 32 a pressure drop relative to the Pressure of the outside atmosphere can be measured. For the function of the measuring channel 30, it is only necessary that the Outside atmosphere throttled with the vacuum chamber 10 in Flow connection is so that the negative pressure in the Vacuum chamber 10 through the outside atmosphere not is disadvantageously reduced or influenced.

Die pro Zeiteinheit geförderte Pulvermenge ist im wesentlichen von der Förderluftrate abhängig. Ein weiteres Kriterium ist die pro Zeiteinheit geförderte Gesamtluftmenge, welche zusammen mit dem Pulver durch die Pulver-Luft-Leitung 2 gefördert wird. Wenn diese Gesamtluftmenge kleiner ist als die Luftmenge, welche erforderlich ist, um das Pulver durch den Pulver-Luft-Kanal 2 zu fördern, ohne daß in ihm Pulverablagerungen entstehen, dann muß zusätzlich Luft hinzugefügt werden, um die Strömungsgeschwindigkeit im Pulver-Luft-Kanal 2 zu erhöhen. Die zusätzliche Luft kann bei Bedarf von der Druckluftquelle 12 über eine Zusatzluftleitung 43 an einem Zusatzlufteinlaß 46 stromabwärts der Unterdruckkammer 10 in den Pulver-Luft-Kanal 2 geleitet werden. In der Zusatzluftleitung 43 befindet sich eine zweite variable Drossel 44, deren Strömungswiderstand (z.B. Strömungsquerschnitt) durch einen antriebsmäßig mit ihr verbundenen Stellmotor 45 von der elektronischen Regelvorrichtung 21 geregelt wird in Abhängigkeit von einem Sollwert für das pro Zeiteinheit geförderte Volumen an Zusatzluft, welcher seinerseits abhängig ist von dem Sollwert für die Pulverrate und/oder von dem Sollwert für die Förderluftrate.The amount of powder delivered per unit of time is in depends essentially on the air flow rate. Another one The criterion is the total air volume delivered per unit of time, which together with the powder through the powder-air line 2 is funded. If this total amount of air is less than the amount of air that is required to flow through the powder to promote the powder-air channel 2 without it Powder deposits develop, then air must be added can be added to the flow velocity in the Increase powder-air channel 2. The additional air can Required from the compressed air source 12 via an additional air line 43 at an additional air inlet 46 downstream of the Vacuum chamber 10 passed into the powder-air channel 2 become. There is a second one in the additional air line 43 variable throttle 44, the flow resistance (e.g. Flow cross section) by a drive with it connected actuator 45 from the electronic Control device 21 is controlled depending on one Setpoint for the volume delivered per unit of time Additional air, which in turn depends on the setpoint for the powder rate and / or from the setpoint for the Conveyor air rate.

Gemäß einer nicht gezeigten Ausführungsform kann Zusatzdruckluft in den Unterdruckbereich 10, 26 geleitet werden zur Beeinflussung des Unterdruckes. According to an embodiment not shown Additional compressed air is passed into the vacuum region 10, 26 are used to influence the negative pressure.

Das in der Unterdruckkammer 10 herrschende Vakuum oder Unterdruck ist nicht absolut konstant und schwankt selbst dann, wenn die Förderluftrate der Injektordüse 6 und die Zusatzluftrate in dem Zusatzlufteinlaß 46 sowie das Pulverniveau 48 im Pulverbehälter 14 konstant gehalten werden. Solche unkontrollierten Schwankungen des Unterdruckes in der Unterdruckkammer 10 führen in unerwünschterweise auch zu Schwankungen der pro Zeiteinheit geförderten Pulvermenge im Pulver-Luft-Kanal 2.The vacuum prevailing in the vacuum chamber 10 or Vacuum is not absolutely constant and fluctuates itself then when the delivery air rate of the injector nozzle 6 and the Auxiliary air rate in the auxiliary air inlet 46 as well Powder level 48 kept constant in the powder container 14 become. Such uncontrolled fluctuations in negative pressure in the vacuum chamber 10 also undesirably lead to fluctuations in the amount of powder conveyed per unit of time in the powder-air channel 2.

Diese Schwankungen beeinträchtigen das Meßergebnis des Meßkanals 30 und damit auch die Regelung der Zufuhr von Fördergas und Zusatzgas. Zur Reduzierung dieses Nachteils ist am stromaufwärtigen Anfang ein Ausgleichsluft-Einlaß 56, z.B. in Form einer zweiten Injektordüse, angeordnet, welche mit kleinem Abstand gegenüber dem stromaufwärtigen Anfang 58 des Pulverauslaßkanals 8 axial angeordnet ist und durch eine dazwischen gebildete zweite Unterdruckkammer 60 Ausgleichsluft axial in den Pulveransaugkanal 8 bläst. Die Ausgleichsluft wird der zweiten Zerstäuberdüse von der Druckluftquelle 12 über eine dritte variable Strömungsdrossel 62 in einer Druckluftleitung 64 und über einen Ausgleichsluftkanal 66 zugeführt. Der Pulveransaugkanal 8 und der Ausgleichsluftkanal 66 befinden sich achsparallel in dem Tauchrohr 24, in dessen unterem Endabschnitt auch die zweite Injektordüse 56 angeordnet ist. Der Pulvereinlaß für den Pulveransaugkanal 8 ist durch eine oder mehrere Pulvereinlaßöffnungen 68 gebildet, welche quer durch das Tauchrohr 24 hindurch die Tauchrohraußenfläche 70 und damit das im Pulverbehälter 14 befindliche Pulver 16 mit der zweiten Unterdruckkammer 60 des zweiten Injektors 72 strömungsmäßig verbinden. Der Strömungswiderstand (z.B. der Strömungsquerschnitt) der dritten variablen Drossel 62 kann fest eingestellt oder manuell oder vorzugsweise durch einen antriebsmäßig mit ihr verbundenen Stellmotor 63 von der Regelvorrichtung 21 in Abhängigkeit von anderen Kriterien (Pulverrate, Förderluftrate und/oder Zusatzluftrate) automatisch eingestellt bzw. geregelt werden.These fluctuations affect the measurement result of the Measuring channel 30 and thus also the control of the supply of Conveying gas and additional gas. To reduce this disadvantage is at the upstream beginning a compensating air inlet 56, e.g. in the form of a second injector nozzle, which with small distance from the upstream beginning 58 of the Powder outlet channel 8 is arranged axially and through a second vacuum chamber 60 formed therebetween Compensating air blows axially into the powder suction channel 8. The Compensating air is supplied by the second atomizer nozzle Compressed air source 12 via a third variable flow restrictor 62 in a compressed air line 64 and via a Compensation air channel 66 supplied. The powder suction channel 8 and the compensation air channel 66 are axially parallel in the Dip tube 24, in the lower end portion of which the second Injector nozzle 56 is arranged. The powder inlet for the Powder suction channel 8 is through one or more Powder inlet openings 68 formed, which across the Dip tube 24 through the dip tube outer surface 70 and thus the powder 16 located in the powder container 14 with the second vacuum chamber 60 of the second injector 72 connect in terms of flow. The flow resistance (e.g. the Flow cross section) of the third variable throttle 62 can fixed or manual or preferably by a drivingly connected to it servomotor 63 from the Control device 21 depending on other criteria (Powder rate, conveying air rate and / or additional air rate) are automatically set or regulated.

Die Regelvorrichtung 21 regelt in Abhängigkeit von dem Meßsignal der Meßleitung 38 und in Abhängigkeit von dem Sollwert oder den Sollwerten der verschiedenen Druckluftarten über die Drosseln 18, 44 und 62 die Zufuhr der Förderluft, der Zusatzluft und/oder der Ausgleichsluft.The control device 21 controls depending on the Measuring signal of the measuring line 38 and depending on the Setpoint or the setpoints of the different types of compressed air via the throttles 18, 44 and 62 the supply of the conveying air, the additional air and / or the balancing air.

Der Pulverbehälter 14 ist vorzugsweise so ausgebildet, daß das in ihm enthaltene Pulver 16 in einem Luftstrom schwebt, dessen Luft durch einen perforierten Behälterboden 74 in das Behälterinnere strömt. Von dem Ausgleichsluft-Einlaß 56 wird eine viel kleinere Menge Luft pro Zeiteinheit in den Pulverstrom eingebracht als mit der ersten Injektordüse 6. Die Ausgleichsluft des Ausgleichseinlasses 56 kann zwar, braucht jedoch nicht in der zweiten Unterdruckkammer 60 Pulver aus dem Pulverbehälter 14 ansaugen. Die Ausgleichsluft wird durch diesen Einlaß 56 mit einer kleinen konstanten Menge pro Zeiteinheit zugeführt und hat dadurch eine stabilisierende Wirkung auf die vorstehend beschriebenen Druckschwankungen im Pulveransaugkanal 8. Die Ausgleichsluft des Ausgleichsluft-Einlasses 56 macht die genannten Schwankungen hochfrequenter (kürzer und schneller) und bezüglich ihrer Amplitude kleiner. Dadurch werden die Reglereinstellzeiten der Regelvorrichtung 21, welche versucht die genannten Schwankungen auszugleichen, wesentlich kürzer. Bei Versuchen konnten die Regeleinstellzeiten auf ein Drittel verkürzt werden.The powder container 14 is preferably designed such that the powder 16 contained in it hovers in an air stream, whose air through a perforated container bottom 74 in the Inside the container flows. From the balance air inlet 56 is a much smaller amount of air per unit time in the Powder stream introduced as with the first injector 6. The compensation air of the compensation inlet 56 can however does not need in the second vacuum chamber 60 Aspirate powder from powder container 14. The balancing air is through this inlet 56 with a small constant Quantity supplied per unit of time and therefore has a stabilizing effect on those described above Pressure fluctuations in the powder intake duct 8. The compensation air of the balance air inlet 56 makes the above Fluctuations of high frequency (shorter and faster) and smaller in amplitude. This will make the Controller setting times of the control device 21 which is trying to compensate for the fluctuations mentioned, much shorter. In trials, the standard setting times could be reduced to a third be shortened.

Die elektronische Regelvorrichtung 21 enthält vorzugsweise einen oder mehrere Mikrocomputer mit Computerprogrammen in der Hardware oder Software zur Ausführung der beschriebenen Verfahren.The electronic control device 21 preferably contains one or more microcomputers with computer programs in the hardware or software for executing the described Method.

Die Regelvorrichtung 21 hat einen Pulver-Sollwert-Eingang 80 zur manuellen oder automatischen Eingabe eines festen oder variablen Sollwertes für die pro Zeiteinheit zu fördernde Pulvermenge "m", beispielsweise in Gramm/Stunde (g/h); einen Gesamtluft-Sollwert-Eingang 81 zur manuellen oder automatischen Eingabe eines festen oder variablen Sollwertes für die Gesamtluft "GV" der durch den Pulver-Luft-Kanal 2 zu strömenden Gesamtluftmenge (Luftvolumenstrom) bestehend aus Förderluft der Förderluftleitung 20, der Zusatzluft der Zusatzluftleitung 43 und der Ausgleichsluft der Ausgleichsluftleitung 64; einen Hochspannungs-Sollwert-Eingang 82 zur manuellen oder automatischen Eingabe eines Hochspannungswertes für eine Hochspannung zur elektrostatischen Aufladung des zu versprühenden Pulvers; und gegebenenfalls einen Sollwert-Eingang 83 für das pro Zeiteinheit zugeführte Ausgleichsluftvolumen "AV" des Ausgleichsluft-Einlasses 56. Das zu versprühende Pulver kann in bekannter Weise durch Elektroden elektrostatisch aufgeladen werden. Die Menge der Ausgleichsluft des Ausgleichslufteinlasses 56 kann, braucht jedoch häufig nicht, bei der Funktion der Regelvorrichtung 21 berücksichtigt zu werden, da ihre Menge sehr viel kleiner ist als die Menge Förderluft. Die Ausgleichsluft des Ausgleichslufteinlasses 56 kann auf einen festen Wert eingestellt werden oder gemäß der Erfindung über eine einstellbare Drossel 62 von einem eigenen Stellmotor 63 von der Regelvorrichtung 21 geregelt werden in Abhängigkeit von anderen Werten, beispielsweise dem Pulver-Sollwert "m" und/oder einem der Luft-Sollwerte.The control device 21 has a powder setpoint input 80 for manual or automatic entry of a fixed or variable setpoint for the to be funded per unit of time Amount of powder "m", for example in grams / hour (g / h); one Total air setpoint input 81 for manual or automatic entry of a fixed or variable setpoint for the total air "GV" through the powder-air channel 2 too total air flow (air volume flow) consisting of Conveying air of the conveying air line 20, the additional air of the Auxiliary air line 43 and the compensation air Compensating air line 64; a high voltage setpoint input 82 for manual or automatic entry of a High voltage value for a high voltage for electrostatic charging of the powder to be sprayed; and possibly a setpoint input 83 for the pro Unit of time supplied equalizing air volume "AV" of the Compensation air inlet 56. The powder to be sprayed can electrostatically by electrodes in a known manner to be charged. The amount of balancing air of the Compensating air inlet 56 can, but often does not need, considered in the function of the control device 21 because their amount is much smaller than the amount Conveying air. The balance air of the balance air inlet 56 can be set to a fixed value or according to the Invention via an adjustable throttle 62 of its own Servomotor 63 are controlled by the control device 21 in Dependence on other values, for example the powder setpoint "m" and / or one of the air setpoints.

In der Regelvorrichtung 21 ist in Form von gespeicherten Daten oder Datenprogrammen gespeichert, wieviel Förderluft und wieviel Zusatzluft über die Förderluftleitung 20 und über die Zusatzluftleitung 43 dem Injektor bei der Einstellung eines bestimmten Pulver-Sollwertes "m" zuzuführen sind, unter Einhaltung des Sollwertes für das Gesamtluftvolumen "GV". Zum Verständnis ist als Beispiel in Fig. 1 in die Regelvorrichtung 21 ein Diagramm eingezeichnet, welches zeigt, daß sich für einen beliebigen eingestellten Pulver-Sollwert "m" in Abhängigkeit von dem vorgegebenen Gesamtluftvolumen-Sollwert "GV" ein bestimmter Sollwert für die Förderluft "FV" ergibt. Aus der rechnerischen Differenz, welche sich aus dem Gesamtluftvolumen "GV" minus dem Förderluft-Volumen "FV" ergibt, bestimmt die Regelvorrichtung einen Differenzbetrag, welcher der Sollwert für die Zusatzluft der Zusatzluftleitung 43 ist. Genauer werden die Werte dann, wenn auch die Ausgleichsluft der Ausgleichsluftleitung 64 bei der Gesamtluftmenge "GV" von der Regelvorrichtung 21 berücksichtigt wird, wie dies bei dem dargestellten Ausführungsbeispiel der Fall ist. In Abhängigkeit von den variablen Werten erzeugt die Regelvorrichtung 21 Stellwerte auf elektrischen Leitungen 85, 86 und 87 für die Stellmotoren 19, 45 und/oder 63. Jeder variablen Drossel ist ein eigener Stellmotor zugeordnet. In the control device 21 is in the form of stored Data or data programs stored, how much conveying air and how much additional air via the conveying air line 20 and over the additional air line 43 to the injector when setting of a specific powder setpoint "m" are to be supplied under Compliance with the target value for the total air volume "GV". To the Understanding is as an example in Fig. 1 in the Control device 21 drawn a diagram, which shows that for any set powder setpoint "m" depending on the given Total air volume setpoint "GV" is a specific setpoint for the conveying air results in "FV". From the arithmetic difference, which results from the total air volume "GV" minus the Conveying air volume "FV" results, determines the control device a difference which is the target value for the Additional air of the additional air line 43 is. They are becoming more precise Values if the balancing air of the Compensating air line 64 for the total air quantity "GV" from the Control device 21 is taken into account, as is the case with the illustrated embodiment is the case. In Dependency on the variable values creates the Control device 21 manipulated values on electrical lines 85, 86 and 87 for the actuators 19, 45 and / or 63. Everyone A variable servo is assigned its own servomotor.

Gemäß der bevorzugten Ausführungsform der Erfindung sind stromabwärts der Drosseln 18, 44 und/oder 62 Sensoren 89, 90 und/oder 91 angeordnet, welche die Istwerte der betreffenden Förderluft, Zusatzluft und/oder Ausgleichsluft in Form von Drücken, Geschwindigkeit und/oder Volumen messen und ein entsprechendes Istwert-Signal der Regelvorrichtung 21 zuführen. Die Regelvorrichtung 21 erzeugt in Abhängigkeit von den ihr vorgegebenen Sollwerten und diesen Istwerten Stellsignale auf den elektrischen Leitungen 85, 86 und/oder 87 der Stellmotoren 19, 45 und/oder 63.According to the preferred embodiment of the invention downstream of the chokes 18, 44 and / or 62 sensors 89, 90 and / or 91 arranged which the actual values of the concerned Conveying air, additional air and / or compensation air in the form of Press, measure speed and / or volume and on corresponding actual value signal of the control device 21 respectively. The control device 21 generates depending on your specified target values and these actual values Control signals on the electrical lines 85, 86 and / or 87 of the servomotors 19, 45 and / or 63.

Die geförderte Pulvermenge pro Zeiteinheit (Pulverrate) ist ungefähr proportional zur pro Zeiteinheit geförderten Förderluftmenge der Förderluftleitung 20. Deshalb braucht lediglich die Förderluft eingestellt zu werden, um eine gewünschte Pulvermenge einzustellen. Die Regelvorrichtung 21 stellt dann automatisch die Zusatzluftrate durch den Stellmotor 45 und die Drossel 44 so ein, daß trotz geänderter Förderluftrate der Gesamtluft-Volumenstrom (Gesamtluftrate) auf dem eingestellten Sollwert bleibt.The amount of powder delivered per unit of time (powder rate) is roughly proportional to the amount funded per unit of time Conveying air quantity of the conveying air line 20. Therefore needs just the conveying air to be adjusted to a set the desired amount of powder. The control device 21 then automatically sets the additional air rate through the Actuator 45 and the throttle 44 so that despite the changed Delivery air rate of the total air volume flow (total air rate) remains at the setpoint.

Die Förderluftrate und die Zusatzluftrate verändern sich, bei konstantem Luftdruck der Druckluftquelle 12, nur dann proportional zu einer Veränderung des Strömungsquerschnittes ihrer Drosseln 18 und 44, wenn der Strömungswiderstand stromabwärts von ihnen sehr klein ist. Bei einer Vorrichtung der vorliegenden Art mit einem Injektor und einer an ihn angeschlossenen Pulverleitung ist jedoch der Strömungswiderstand so groß, daß die Förderlufrate und die Zusatzluftrate sich nicht linear zu Änderungen der Strömungsquerschnitte der Drosseln 18 und 44 ändern. Gemäß einer bevorzugten Ausführungsform der Erfindung ist in der Regelvorrichtung 21 die nicht-lineare Abhängigkeit für mindestens einen oder mehrere Strömungswiderstände (verschiedene Injektoren 4 und/oder Pulverleitungen) diagrammartig derart gespeichert, daß die Regelvorrichtung 21 die Drosseln 18 und 44 durch die Stellmotore 19 und 45 in Abhängigkeit von Sollwertvorgaben nicht-linear so ansteuert, daß sich eine zur Sollwertänderung lineare Veränderung der Förderluftrate und/oder der Zusatzluftrate ergibt.The conveying air rate and the additional air rate change, at constant air pressure of the compressed air source 12, only then proportional to a change in the flow cross-section their throttles 18 and 44 when the flow resistance downstream of them is very small. With one device of the present type with an injector and one attached to it connected powder line is, however Flow resistance so great that the delivery air rate and the Additional air rate is not linear to changes in Change flow cross-sections of restrictors 18 and 44. According to a preferred embodiment of the invention is in the Control device 21 the non-linear dependency for at least one or more flow resistances (different injectors 4 and / or powder lines) stored diagrammatically in such a way that the control device 21 the chokes 18 and 44 by the servomotors 19 and 45 in Controlling dependency on setpoint values non-linearly, that there is a linear change in the setpoint change in the Delivery air rate and / or the additional air rate results.

Claims (6)

  1. Powder spray coating device comprising an injector (4) provided between an injector nozzle (6) and an axially opposite powder/air duct (2) with a negative-pressure region (10) for the intake of powder from a powder source, a conveying-air line (20) connected to the injector nozzle in order to supply compressed air serving as conveying air thereto, an electronic control system (21) for controlling the conveying air as a function of a powder setpoint and an actual value for the quantity of powder to be conveyed per unit of time, a measuring device (30, 36, 38) connected to the negative-pressure region (10) of the injector (4) and supplying an actual-value signal corresponding to the respective negative pressure to the control system (21), interpreted by the control system (21) as an actual value for the quantity of powder to be conveyed per unit of time, and a control element (18) in the conveying-air line (20) for adjusting the conveying air by means of the control system (21) as a function of the powder setpoint and the actual powder value, characterised in that the control element (18) is a variable restrictor (18) the flow resistance of which can be adjusted by a motor and that the restrictor (18) is operatively connected to a servomotor (19) which can be activated by actuating signals from the control system (21).
  2. Powder spray coating device according to claim 1, characterised in that a supplementary-air line (43) is connected to a supplementary-air inlet (46) of the injector (4) opening downstream of the negative-pressure region (10) into the powder/air duct (2) for the supply of compressed air serving as supplementary air, that a variable restrictor (44) the flow resistance of which can be adjusted by a motor is arranged in the supplementary-air line (43) and that the restrictor (44) is operatively connected to a servomotor (45) which can be activated by manipulated-variable signals from the control system (21) as a function of the powder setpoint (m) and as a function of a setpoint for the total quantity of air to flow through the powder/air duct (2) per unit of time.
  3. Powder spray coating device according to claim 1 or claim 2, characterised in that a powder-intake duct (8) is connected to the negative-pressure region (10) and that a compensating-air inlet (56) for supplying compensating air into the powder-intake duct (8) in order to compensate for possible flow pulses is provided at the end of the powder-intake duct (8) at a distance from the negative-pressure region (10), the quantity of compensating air supplied per unit of time being substantially smaller than the quantity of conveying air supplied per unit of time.
  4. Powder spray coating device according to claim 3, characterised in that a variable restrictor (62) the flow resistance of which can be adjusted by a motor is arranged in the compensating-air line (64) and that the restrictor (62) is operatively connected to a servomotor (63) which can be activated and controlled by the control system (21).
  5. Powder spray coating device according to one of claims 1 to 4, characterised in that a measuring means (89) is provided in the conveying-air line (20) downstream of its restrictor (18) and supplies an actual-value signal to the control system (21) as a function of the flow conditions in the conveying-air line and that the control system (21) is designed in such a manner that it also generates the actuating signals for his restrictor (18) as a function of these actual-value signals for the conveying air.
  6. Powder spray coating device according to one of claims 2 to 5, characterised in that a measuring means (90) is provided in the supplementary-air line (43) downstream of its restrictor (44) and supplies an actual-value signal to the control system (21) as a function of the flow conditions in the supplementary-air line (43) and that the control system (21) is designed in such a manner that it also generates the actuating signals for this restrictor (44) as a function of these actual-value signals for the supplementary air.
EP99927926A 1998-08-22 1999-06-09 Powder spray coating device Expired - Lifetime EP1104334B1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE19838276 1998-08-22
DE19838276A DE19838276A1 (en) 1998-08-22 1998-08-22 Powder spray coating arrangement has variable choke control element in delivery airline whose flow resistance can be varied by control motor activated by electronic regulator
PCT/EP1999/003967 WO2000010726A1 (en) 1998-08-22 1999-06-09 Powder spray coating device

Publications (2)

Publication Number Publication Date
EP1104334A1 EP1104334A1 (en) 2001-06-06
EP1104334B1 true EP1104334B1 (en) 2003-11-05

Family

ID=7878448

Family Applications (1)

Application Number Title Priority Date Filing Date
EP99927926A Expired - Lifetime EP1104334B1 (en) 1998-08-22 1999-06-09 Powder spray coating device

Country Status (8)

Country Link
US (1) US6598803B1 (en)
EP (1) EP1104334B1 (en)
JP (1) JP3426215B2 (en)
AT (1) ATE253411T1 (en)
CA (1) CA2341221A1 (en)
DE (2) DE19838276A1 (en)
ES (1) ES2211105T3 (en)
WO (1) WO2000010726A1 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2006024417A1 (en) * 2004-09-02 2006-03-09 Weitmann & Konrad Gmbh & Co. Kg Device and method for the production of a homogeneous powder-air mixture
US8353467B2 (en) 2007-07-04 2013-01-15 Ga-Rew Corporation Fluid spraying gun

Families Citing this family (20)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB0100756D0 (en) 2001-01-11 2001-02-21 Powderject Res Ltd Needleless syringe
FR2824283B1 (en) * 2001-05-03 2004-10-29 Eisenmann France Sarl METHOD FOR REGULATING THE FLOW OF POWDER TRANSPORTED BY AN AIR FLOW, AND DEVICE FOR IMPLEMENTING IT
SE525718C2 (en) * 2002-04-11 2005-04-12 Eltex Sweden Ab Device at a nozzle for regulating a gas or liquid
WO2003099450A1 (en) * 2002-05-10 2003-12-04 Eisenmann France Sarl Method for regulating flow of powder carried by an air stream, and device therefor
US7418832B2 (en) * 2003-10-21 2008-09-02 William R Ferrono Portable mister for adjusting ambient temperature
DE10357814A1 (en) * 2003-12-10 2005-07-14 Itw Gema Ag Gas line system, in particular in a powder spray coating device
DE102004052949A1 (en) * 2004-10-29 2006-05-04 Nordson Corp., Westlake Method and device for monitoring flow conditions in a wiring harness
DE102005007242A1 (en) * 2005-02-17 2006-08-24 Itw Gema Ag Compressed air throttle device and powder spray coating device
FR2892647B1 (en) * 2005-10-28 2008-02-22 Turbomeca SPRAY APPARATUS
EP1958899B1 (en) * 2007-02-16 2013-08-21 J. Wagner AG Device for transporting fluids
GB0708758D0 (en) 2007-05-04 2007-06-13 Powderject Res Ltd Particle cassettes and process thereof
DE102007049169A1 (en) * 2007-10-13 2009-04-16 Itw Gema Gmbh Powder spray coating controller and its combination with a powder feeder or with a powder spray coater
US20120173028A1 (en) * 2009-09-18 2012-07-05 Sung Soo Wui Ultra-low volume spraying device
TW201604465A (en) * 2010-06-15 2016-02-01 拜歐菲樂Ｉｐ有限責任公司 Methods, devices and systems for extraction of thermal energy from a heat conducting metal conduit
DE102010039473B4 (en) * 2010-08-18 2014-11-20 Gema Switzerland Gmbh Powder supply device for a powder coating system
DE102012013523A1 (en) * 2012-07-06 2014-01-09 Knorr-Bremse Systeme für Schienenfahrzeuge GmbH Control valve with a device for generating defined braking and release times
DE102013211550A1 (en) * 2013-06-19 2014-12-24 Gema Switzerland Gmbh Powder conveying device, in particular for coating powder
US9605789B2 (en) 2013-09-13 2017-03-28 Biofilm Ip, Llc Magneto-cryogenic valves, systems and methods for modulating flow in a conduit
DE102016106052A1 (en) * 2015-11-10 2017-05-11 Sms Group Gmbh Venturi nozzle, powder blowing apparatus and method of operating a powder blowing apparatus
US10401246B2 (en) * 2017-05-31 2019-09-03 Oerlikon Metco (Us) Inc. Powder feed control system and method

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0643911B2 (en) * 1985-09-17 1994-06-08 アイ・ティー・エム株式会社 Gas carrier powder supply system
JPH0780567B2 (en) * 1986-03-25 1995-08-30 秀雄 長坂 Automatic powder feeder
JPH06246196A (en) * 1993-02-22 1994-09-06 I T M Kk Powder supplying device, electrostatic powder coating device and powder flow rate measuring instrument
DE4325044C2 (en) * 1993-07-26 2002-07-18 Itw Gema Ag Powder conveying device, in particular for coating powder
DE4419987A1 (en) * 1994-06-08 1996-02-29 Gema Volstatic Ag Injector conveyor for the pneumatic conveying of powder
DE19541228C2 (en) * 1995-11-06 1997-08-21 Schlick Heinrich Gmbh Co Kg Device for dosing granular, free-flowing materials, in particular blasting media
US5676494A (en) * 1996-03-14 1997-10-14 The United States Of America As Represented By The Department Of Energy Particle injector for fluid systems
JP3867176B2 (en) * 1996-09-24 2007-01-10 アール・アイ・ディー株式会社 Powder mass flow measuring device and electrostatic powder coating device using the same
DE19838279A1 (en) * 1998-08-22 2000-02-24 Itw Gema Ag Powder coating system has an injector stage with air supply controlled by restrictor valves that are coupled to a processor

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2006024417A1 (en) * 2004-09-02 2006-03-09 Weitmann & Konrad Gmbh & Co. Kg Device and method for the production of a homogeneous powder-air mixture
US8353467B2 (en) 2007-07-04 2013-01-15 Ga-Rew Corporation Fluid spraying gun

Also Published As

Publication number Publication date
CA2341221A1 (en) 2000-03-02
DE19838276A1 (en) 2000-02-24
EP1104334A1 (en) 2001-06-06
JP3426215B2 (en) 2003-07-14
DE59907645D1 (en) 2003-12-11
JP2002523216A (en) 2002-07-30
ES2211105T3 (en) 2004-07-01
WO2000010726A1 (en) 2000-03-02
US6598803B1 (en) 2003-07-29
ATE253411T1 (en) 2003-11-15

Similar Documents

Publication Publication Date Title
EP1104334B1 (en) Powder spray coating device
EP0412289B1 (en) Electrostatic spray device
EP0636420B1 (en) Powder conveying device, in particular for coating powder
DE2758096C2 (en) Method and device for automatic dynamic dosing of at least one liquid component of a mixed liquid
EP0686430A2 (en) Injector for pneumatically transporting powder
EP0823286B1 (en) Injector arrangement for transporting particulate materials
EP0780160B1 (en) Powder spray coating device
EP1550511B1 (en) Device and method for producing an aerosol
EP1929253A2 (en) Method for controlling a dosing apparatus for liquid or pasty media
EP0913203B1 (en) Method and apparatus for powder coating with purging air supply
EP1104335B1 (en) Powder spray coating device
DE3821440A1 (en) METHOD AND DEVICE FOR FEEDING SPRAY MATERIALS TO A MULTIPLE NUMBER OF SPRAYING DEVICES
EP1115499B1 (en) Powder coating device
DE19748376A1 (en) Method and device for powder spray coating
EP1240947A1 (en) Powder spray device for coating powder
EP1123163B1 (en) Method and device for dosing and mixing different components
CH668566A5 (en) ARRANGEMENT ON ROAD MARKING MACHINES FOR THE AUTOMATIC CONTINUOUS MAINTENANCE OF THE LAYER THICKNESS OF MARKING LINES.
CH688989A5 (en) Apparatus for conveying powder
EP1481736A2 (en) Supply device for a painting installation
DE10357814A1 (en) Gas line system, in particular in a powder spray coating device
DE10111383B4 (en) Process for conveying coating powder to a coating unit and associated powder conveying device
EP3711864B1 (en) Method for controlling the supply pressure in a circulation system for a coating device and circulation system
DE60222940T2 (en) METHOD AND DEVICE FOR REGULATING THE POWDER QUANTITY IN A CARRIER GAS
WO1999019528A1 (en) Method and device for coating a metal strip

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 20001117

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AT CH DE ES FR GB IT LI NL

GRAH Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOS IGRA

GRAH Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOS IGRA

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): AT CH DE ES FR GB IT LI NL

REG Reference to a national code

Ref country code: GB

Ref legal event code: FG4D

Free format text: NOT ENGLISH

REG Reference to a national code

Ref country code: CH

Ref legal event code: EP

GBT Gb: translation of ep patent filed (gb section 77(6)(a)/1977)

Effective date: 20031105

REG Reference to a national code

Ref country code: CH

Ref legal event code: NV

Representative=s name: E. BLUM & CO. PATENTANWAELTE

REF Corresponds to:

Ref document number: 59907645

Country of ref document: DE

Date of ref document: 20031211

Kind code of ref document: P

REG Reference to a national code

Ref country code: ES

Ref legal event code: FG2A

Ref document number: 2211105

Country of ref document: ES

Kind code of ref document: T3

ET Fr: translation filed
PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed

Effective date: 20040806

REG Reference to a national code

Ref country code: CH

Ref legal event code: PFA

Owner name: ITW GEMA AG

Free format text: ITW GEMA AG#MOEVENSTRASSE 17#9015 ST. GALLEN (CH) -TRANSFER TO- ITW GEMA AG#MOEVENSTRASSE 17#9015 ST. GALLEN (CH)

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: NL

Payment date: 20081219

Year of fee payment: 10

Ref country code: CH

Payment date: 20081212

Year of fee payment: 10

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: AT

Payment date: 20081211

Year of fee payment: 10

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: IT

Payment date: 20081210

Year of fee payment: 10

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: ES

Payment date: 20090113

Year of fee payment: 10

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 20081231

Year of fee payment: 10

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: GB

Payment date: 20081209

Year of fee payment: 10

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 20081210

Year of fee payment: 10

REG Reference to a national code

Ref country code: CH

Ref legal event code: PL

GBPC Gb: european patent ceased through non-payment of renewal fee

Effective date: 20090609

NLV4 Nl: lapsed or anulled due to non-payment of the annual fee

Effective date: 20100101

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST

Effective date: 20100226

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: LI

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20090630

Ref country code: FR

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20090630

Ref country code: CH

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20090630

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20090609

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20100101

Ref country code: AT

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20090609

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: NL

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20100101

REG Reference to a national code

Ref country code: ES

Ref legal event code: FD2A

Effective date: 20090610

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: ES

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20090610

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: IT

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20090609