EP0750945A1 - Dispositif de pulvérisation de peintures conductrice - Google Patents

Dispositif de pulvérisation de peintures conductrice Download PDF

Info

Publication number
EP0750945A1
EP0750945A1 EP96110165A EP96110165A EP0750945A1 EP 0750945 A1 EP0750945 A1 EP 0750945A1 EP 96110165 A EP96110165 A EP 96110165A EP 96110165 A EP96110165 A EP 96110165A EP 0750945 A1 EP0750945 A1 EP 0750945A1
Authority
EP
European Patent Office
Prior art keywords
paint
voltage
hose
line
pump
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.)
Withdrawn
Application number
EP96110165A
Other languages
German (de)
English (en)
Inventor
Paul Borer
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.)
Individual
Original Assignee
Individual
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 Individual filed Critical Individual
Publication of EP0750945A1 publication Critical patent/EP0750945A1/fr
Withdrawn legal-status Critical Current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
    • 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

Definitions

  • the invention relates to a device according to claim 1.
  • Electrostatic painting can lead to material savings of up to 40%, cost savings, time savings and quality improvements.
  • water-soluble paints are also increasingly being used in industrial production.
  • the water-soluble paints have a high conductivity, so that the entire amount of paint is brought to high voltage, in particular of approximately 90 kV, by a high-voltage electrode which is in contact with the paint in the spray gun.
  • High voltage in particular of approximately 90 kV
  • Large amounts of paint at high voltages can quickly discharge in the event of unwanted short circuits and thus form a source of danger.
  • the voltage losses are undesirably large with large quantities of paint and the associated long line systems.
  • the paint is only electrically charged in the spray jet, so that the paint supplied to the spray gun is not charged due to the air separation between the paint drops in the jet and the paint in the spray nozzle.
  • this external charge is not sufficiently complete, so that only small ones Material savings of up to about 10% can be achieved.
  • the amount of paint connected to the electrode via the paint supply is reduced, for example by guiding paint from a storage tank into at least one intermediate tank such that the storage tank and the intermediate tank are never electrically conductively connected by the incoming paint, or else are only conductively connected if the line from the intermediate container to the spray gun is color-free and therefore not conductive.
  • These devices are of complex construction since they require at least two paint containers and, for example, a conveying system for conveying separate portions of paint or a controlled valve system in order to rinse and dry the connecting line between the two containers, for example.
  • these systems are usually designed to alternately fill the at least one intermediate container with different colors from correspondingly different storage containers. Since these are systems that are preferably used in the automotive industry for spraying body parts in production lines, color changes take place automatically through the metered filling of a second intermediate container and the subsequent emptying of the connecting lines from the storage container to the second intermediate container and from the first intermediate container to the spray gun, and so on Connect the second intermediate container to the spray gun
  • the object of the invention is now to describe a spraying device which is simple in construction, easy to use and can be used safely, and which enables simple color changes.
  • the complexity of the known systems results from the fact that they include at least one storage container belonging to the device and usually also an intermediate container that can be filled from it.
  • the connection of the reservoir with the spraying device under high voltage results Refill problems. If only one storage container were provided, it would have to be emptied and cleaned for a color change. Because this is too complex, the known solutions usually provide a storage container for each color. In the case of several storage containers, however, the line systems from the storage containers to the spray gun must be provided with valves and rinsing-drying devices, which leads to a complex construction.
  • the spray device instead of a storage container only has to comprise an electrically insulating receiving device, preferably an insulating cabinet, for commercially available paint containers.
  • an electrically insulating receiving device preferably an insulating cabinet
  • the storage container belonging to the spraying device does not have to be emptied and cleaned, but only the paint container in the receiving device has to be replaced.
  • a first end of a suction hose which can be inserted into the paint container is provided in the receiving device.
  • a second end of this suction hose is connected to the suction side of a pump.
  • a paint line leads from the pressure side of the pump to the spray gun.
  • the suction hose is cleaned after the first paint container has been removed.
  • a container with cleaning liquid in particular water, is preferably placed in the receiving device, the first end of the suction hose is inserted therein and the suction hose, the pump, the paint line and the spray gun are rinsed with the cleaning liquid.
  • the container with cleaning liquid is removed and a paint container is inserted.
  • the cleaning step can be carried out without a control unit and without a valve system and is time-consuming. Since there is no storage container, only the connecting line from the paint container to Spray gun needs to be cleaned, there is little paint to be disposed of, or cleaning liquid with paint.
  • the receiving device is provided with a closable opening, in particular a door, a grounding device ensuring that when the opening or the door is opened, at least the paint in the suction hose and paint container is grounded.
  • the pump is preferably also arranged in the receiving device. So that the pump can only be touched when it is earthed, the pump in particular is also connected to the earthing device.
  • the receiving device is designed to be electrically insulating, so that at least on its outside no significant voltages arising from the high voltage applied to the paint can occur.
  • the receiving device eliminates the risk of contact with live paint and electrically connected parts.
  • the insulation is preferably applied in such a way that the voltage losses of the high-voltage paint are negligible.
  • the high voltage comes from a high voltage generator, which is fed by a high voltage control, preferably with direct current low voltage, and outputs the voltage to the paint via an electrode.
  • the high-voltage control is preferably designed to limit the current, so that the supply is switched off in the event of excessive electrostatic discharge or, for example, when the spray gun is connected to earth via a sufficiently small resistor. In the event of a short circuit, only the charge in the paint flows off as a current surge. The high voltage is switched off immediately.
  • the high-voltage control is switched on and off by actuating the spray gun trigger, that is to say the charging of the paint to high voltage takes place when spraying or spraying the paint.
  • the grounding device is preferably connected to a switch which ensures that the grounding is only switched off during spraying or the paint is always grounded when the spraying process is interrupted.
  • This switch can be designed as a flow switch and switched depending on the color flow. If necessary, a switch operated by the trigger of the spray gun is used. Because the high-voltage switch-on or switch-off should essentially take place together with the ground switch-off or switch-on, both can be controlled via a common switch. An output signal from the high-voltage circuit may be used to control the grounding circuit.
  • the paint line comprises at least one layer of polyurethane, which optionally completely surrounds a Teflon tube on the outside.
  • a Teflon tube with a surrounding polyurethane coating has the advantage that the paint is in contact with the color-stable and easy-to-clean Teflon and the good electrical insulation properties of the polyurethane can also be used.
  • Another advantage of this combination of materials is that the brittle deformation properties of Teflon combined with the extremely elastic properties of the polyurethane lead to advantageous hose properties.
  • a reinforcing fabric in particular a Teflon fabric, is optionally arranged between the Teflon tube and the polyurethane layer. If necessary, the Teflon fabric is used instead of the Teflon tube and is approximately coated on the inside.
  • the Teflon polyurethane hose according to the invention is optimally bendable but not easily kinkable and crushable. Due to the high electrical resistance in the radial direction, this combination hose is particularly suitable as a paint line for paints that are under high voltage.
  • the polyethylene hoses commonly used as color lines have an electrical resistance that is too low, so that there are excessive voltage losses.
  • the combination hose may also consist of a polyethylene hose which is surrounded by or coated with polyurethane. Polyurethane hoses that are coated on the inside in particular are also possible.
  • it is expedient for use in high-pressure spraying if a reinforcing fabric, preferably a cotton fabric, or in particular a teflon fabric is arranged in the hose wall.
  • a cost-effective hose with the necessary insulation and stability properties is obtained by placing a polyurethane hose on the inside and a silicone hose on the outside.
  • the polyurethane hose ensures the necessary stability and, as already described, has good insulation properties.
  • the wall thickness of the polyurethane hose In order not to unnecessarily restrict the mobility of the hose, the wall thickness of the polyurethane hose must not be chosen too large.
  • the outer hose is made of silicone. Silicone hoses have good electrical insulation properties and are very flexible. The combination of polyurethane and silicone enables a combination hose to be formed with optimal insulation and mobility.
  • a polyurethane hose is preferably surrounded with a reinforcing fabric, in particular a cotton fabric, and then coated with polyurethane, so that the fabric lies in the polyurethane hose.
  • the polyurethane hose is then pulled into a silicone hose.
  • a coating could also be provided, or the fabric could also be arranged in the silicone layer or adjacent to it.
  • at least one further hose layer could also be provided in addition to the reinforcing fabric.
  • a combination hose is also new and inventive, regardless of the spray device.
  • the wall thicknesses of the layers of a combination hose depend on its area of application. If the pressure in the ink line is in the low and lower medium pressure range, i.e. below essentially 30 bar, a polyurethane layer thickness of essentially 1 mm and a silicone layer thickness of essentially 3 mm are sufficient in the example of the polyurethane silicone hose.
  • a reinforcement fabric is used for the high pressure range up to 120bar and the wall thickness of the internal polyurethane hose is essentially 2mm.
  • the wall thickness of the Teflon tube is in a range from 0.1 to 5 mm, but preferably from 0.8 to 2 mm, in particular essentially 1.2 mm.
  • the polyurethane layer has a wall thickness of 1.5 to 8 mm, preferably 2 to 4 mm, in particular essentially 3 mm.
  • the wall thickness of the polyurethane hose is in a range from 0.1 to 5 mm, but preferably from 0.8 to 2 mm, for low-pressure or. High pressure applications, in particular essentially at 1mm or at 2mm.
  • the outside silicone tube has a wall thickness of 1 to 8 mm, preferably 2 to 4 mm, in particular essentially 3 mm.
  • the high voltage at which the best paint application or the greatest paint saving is achieved depends on the water-based paint used, in particular its conductivity. Compared to known devices, the device according to the invention achieves better results even with smaller high voltages due to the small voltage losses and the small interference fields. With a high voltage in the range of preferably 20 kV to 65 kV, in particular essentially 55 kV, essentially all common water-based paints can be optimally applied.
  • the high-voltage lines available in versions according to the prior art, which lead, for example, from a high-voltage generator in the high-voltage control to the spray gun.
  • the high-voltage generator is located directly at an electrode connected to it, which is in contact with paint in the operating state and, for example, in the paint container, in particular in the suction hose, or if appropriate is arranged in the paint line, but preferably in the spray gun.
  • the simple structure of the spraying device and the optimal and safe electrical insulation, an undisturbed field required for extensive spraying can be built up with a minimal leakage current. Compared to the spraying of unloaded paints, ink volume savings of up to 50% can be achieved. This is significantly higher than in the systems according to the prior art.
  • the spray device is also inexpensive, risk-free and enables color changes with little effort.
  • the simple structure of the spraying device and an easy-to-use, current-limited high-voltage control enable operation even by untrained personnel.
  • the inventive solution can also be expanded for use in automated production processes.
  • a control unit and an automatic device for inserting and removing the suction hose into or out of the paint container must be provided in the receiving device.
  • This device preferably also enables the closing, putting on and opening or removing ink container lids.
  • Color containers can be exchanged, for example, with a conveyor system, as is common in warehouses. Such a system is not limited to processing a number of colors limited by the number of reservoirs.
  • a spray device 1 which comprises a spray gun 2, at least one connecting line 3, a high-voltage control 4 and an insulating cabinet 5 as a receiving device for paint containers.
  • An operator 6 sprays or sprays with the spray gun 2 Water-based paint on a workpiece 7.
  • the gun 2 is designed as an airless or air atomizing gun.
  • At least one paint line 3a is provided as the connecting line 3, which leads paint from the pressure side of a pump 8 to the gun 2.
  • An electrical connection 3b preferably leads from the high-voltage controller 4 to the gun 2.
  • the electrical connection 3b comprises a control line and / or a low-voltage supply for a high-voltage generator which is preferably arranged in the gun 2.
  • the control line enables the high voltage to be switched on and off from the gun.
  • a compressed air line 3c leads from a compressed air source to the pistol 2 as a further connecting line.
  • an earthing line is preferably led to the pistol grip.
  • this line does not lead to an increased discharge of the paint.
  • the paint line 3a is connected to a paint guide in the gun to the outlet nozzle, which is also very well insulated electrically.
  • the receiving device comprises at least a first, essentially completely lockable receiving area 9a, in which a paint container 10 can be arranged, and an intake hose 11, the first end of which can be inserted into the paint container 10 and the second end of which on the suction side the pump 8 is connected.
  • the receiving area 9a is designed as a box, which is accessible through a front door opening 12 '.
  • the door opening 12 ' can be closed by a door 12 with a locking device 12a.
  • the receiving area 9a is preferably completely surrounded by electrically insulating material, so that an electrically conductive paint container 10 can also be used without problems.
  • the electrically conductive paint creates an electrical connection from the gun 2 via the paint line 3a, the pump 8 and the suction hose 11 to the paint of the paint container 10.
  • the paint may now only be under high voltage if neither the paint nor the electrically conductive paint Parts that are connected in a color-conductive manner are freely accessible.
  • the pump has electrically conductive parts which are conductively connected to the paint and are accessible from the outside, it is preferably arranged in a second receiving area 9b of the insulating cabinet 5, which is located approximately below the first.
  • the door 12 preferably closes both receiving areas 9a and 9b.
  • An earthing device comprises at least one earthing switch 13 which, when the door 12 is not completely closed, connects all the live paint and preferably the pump via corresponding earthing lines 13a to a line connected to earth.
  • a closed position switch 14 is connected to mutually assigned parts 14a, 14b, one of which is arranged on the door 12 and the other on the door frame, via control lines 15 to the earthing switch 13.
  • the high-voltage controller 4 comprises a display field 4a and an input field 4b.
  • the high voltage is preferably switched on and off from the gun 2 via a control line. Since a short-circuit fuse is preferably installed, the high-voltage supply is also switched off when the earthing switch 13 is earthed.
  • a high-voltage generator fed by the high-voltage controller 4 is arranged in the gun, embodiments are also possible in which the high-voltage generator is arranged, for example, on a holder 16 of the suction hose 11, on the pump 8, or on the paint line 3a .
  • a feed line 17 would be provided for supplying a high-voltage generator in the holder 16.
  • the high-voltage controller 4 is switched on and off by actuating the spray gun trigger, that is to say the paint is charged to high voltage when the paint is sprayed or sprayed.
  • the grounding device preferably comprises an operating switch 21 which ensures that the grounding is only switched off during the spraying or the paint is always grounded when the spraying process is interrupted .
  • the earthing device comprises the earthing switch 13, which interrupts an earthing line 13a in the actuated state or under operating voltage and ensures earthing in the unactuated state.
  • a control relay 21 is provided for switching on and off the operating voltage, or the power supply 20, of the earthing switch, the state of which depends on the position of two control switches arranged in series.
  • the first control switch is the closed position switch 14 and the second is the operating switch 21, in particular a flow switch switched by the paint or compressed air flow, which is switched on during spraying and switched off when spraying is interrupted.
  • the control switches could be provided directly to interrupt the operating voltage of the earthing switch 13. Because the spray device 1 may also process paints with solvents, it is advisable to use an explosion-proof circuit with a low voltage. Instead of the flow switch, a switch operated by the trigger of the spray gun can also be used. If necessary, an output signal of the high-voltage circuit is used to control the grounding circuit instead of the second control switch.
  • the receiving device 5 can be designed in a wide variety of forms.
  • the door could also be provided at the top.
  • the device according to the invention enables a good grip.
  • the overspray is reduced.
  • electrically driven pumps constant grounding is not necessary.
  • pneumatically driven pumps no earthing is provided anyway.
  • plastic pumps the pump does not have to be arranged in the holding device because there is no high-voltage contact area.
  • Embodiments in which the high voltage in the gun or directly in front of the outlet nozzle is transferred to the paint are suitable both for the electrostatic application of conductive paints, such as water-based paints, and for the application of paints with very low conductivity, such as synthetic resins. These embodiments therefore have the advantage that they can be used for all electrostatically chargeable substances.

Landscapes

  • Application Of Or Painting With Fluid Materials (AREA)
  • Electrostatic Spraying Apparatus (AREA)
EP96110165A 1995-06-27 1996-06-24 Dispositif de pulvérisation de peintures conductrice Withdrawn EP0750945A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CH1881/95 1995-06-27
CH188195 1995-06-27

Publications (1)

Publication Number Publication Date
EP0750945A1 true EP0750945A1 (fr) 1997-01-02

Family

ID=4220772

Family Applications (1)

Application Number Title Priority Date Filing Date
EP96110165A Withdrawn EP0750945A1 (fr) 1995-06-27 1996-06-24 Dispositif de pulvérisation de peintures conductrice

Country Status (1)

Country Link
EP (1) EP0750945A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6776308B1 (en) 2002-06-12 2004-08-17 Dave D. Davis Apparatus with multiple paint intakes
DE102004033330A1 (de) * 2004-07-09 2006-02-02 Dürr Systems GmbH Schlauchführung für einen Lackierroboter

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1777353A1 (de) * 1968-04-26 1972-12-21 Mueller Ernst Kg Vorrichtung zum Beschichten von Werkstuecken mit elektrostatischem Feld
US3864603A (en) * 1973-11-12 1975-02-04 Graco Inc High voltage safety apparatus
US3929286A (en) * 1975-01-29 1975-12-30 Nordson Corp Apparatus and method for electrostatically spraying highly electrically conductive water-based coating material
US4151428A (en) * 1976-06-23 1979-04-24 Roger Morel Coating objects by electrostatic spraying
EP0602434A1 (fr) * 1992-12-11 1994-06-22 Ransburg Corporation Réservoir d'alimentation de peinture sous pression électriquement isolé

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1777353A1 (de) * 1968-04-26 1972-12-21 Mueller Ernst Kg Vorrichtung zum Beschichten von Werkstuecken mit elektrostatischem Feld
US3864603A (en) * 1973-11-12 1975-02-04 Graco Inc High voltage safety apparatus
US3929286A (en) * 1975-01-29 1975-12-30 Nordson Corp Apparatus and method for electrostatically spraying highly electrically conductive water-based coating material
US4151428A (en) * 1976-06-23 1979-04-24 Roger Morel Coating objects by electrostatic spraying
EP0602434A1 (fr) * 1992-12-11 1994-06-22 Ransburg Corporation Réservoir d'alimentation de peinture sous pression électriquement isolé

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6776308B1 (en) 2002-06-12 2004-08-17 Dave D. Davis Apparatus with multiple paint intakes
DE102004033330A1 (de) * 2004-07-09 2006-02-02 Dürr Systems GmbH Schlauchführung für einen Lackierroboter

Similar Documents

Publication Publication Date Title
DE69326519T2 (de) Vorrichtung und Verfahren zur Abgabe von leitfähigen Beschichtungsmaterialien
DE2937879C2 (fr)
EP1108475B1 (fr) Installation de peinture
DE69109823T2 (de) Elektrostatische Farbspritzanlage für eine leitfähige Beschichtungsflüssigkeit.
DE3014221A1 (de) Verfahren und vorrichtung zum elektrostatischen spritzen
DE2317862C3 (de) Vorrichtung zum elektrostatischen Versprühen eines elektrisch leitenden Beschichtungsmaterials
DE19937426A1 (de) Lackiervorrichtung
WO2000010724A1 (fr) Pistolet de pulverisation pour l'application d'un revetement sur des objets
EP1108474B1 (fr) Installation de peinture
EP1344572B1 (fr) Installation de peinture pour revêtir des objets par un revêtement liquide
DE60302702T2 (de) Verfahren und Vorrichtung zur Lackversorgung einer Auftragsvorrichtung sowie zu deren Spülung
DD270665A5 (de) Verfahren und anlage zum elektrostatischen beschichten im leitfaehigem material
EP0455111B1 (fr) Installation pour revêtir en série des pièces d'oeuvre d'un matériau de revêtement conducteur
DE10131562A1 (de) Verfahren und System zur Versorgung einer Beschichtungsvorrichtung
DE60303060T2 (de) Verfahren und Vorrichtung zur Versorgung und Auftragung von elektrisch leitfähigem Lack
DE4240328C2 (de) Elektrostatische Sprühbeschichtungsvorrichtung für elektrisch leitfähige, nicht brennbare Beschichtungsflüssigkeit
EP0455109B1 (fr) Procédé et installation de revêtement en series de pièces avec un produit de revêtement conducteur
DE4201521A1 (de) Vorrichtung zum unterbinden von leckstroemen aus geraeteteilen fuer das elektrostatische farbspritzen
EP0750945A1 (fr) Dispositif de pulvérisation de peintures conductrice
EP0455106B1 (fr) Procédé et installation pour revêtir en série des pièces d'oeuvre d'un matériau de revêtement conducteur
EP0125589B1 (fr) Projection ou pulvérisation électrostatique de liquides électro-conducteurs, par example d'agents pour traiter des plantes
EP1500435B1 (fr) Procédé et dispositif de commande de potentiel d'un arangement de tuyauteries nettoyées par raclage
DE4433113C2 (de) Einrichtung zum Aufladen und Abgeben elektrisch leitfähigen Sprühgutes
EP3017873B1 (fr) Systeme de revetement d'objets
DE9218593U1 (de) Elektrostatische Sprühbeschichtungsvorrichtung für elektrisch leitfähige, nicht brennbare Beschichtungsflüssigkeit

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

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AT BE CH DE DK ES FI FR GB GR IT LI NL PT SE

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

Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN

18D Application deemed to be withdrawn

Effective date: 19970703