DK168943B1

DK168943B1 - Method for delivering an electrically conductive, fluid medium and apparatus for performing the method

Info

Publication number: DK168943B1
Application number: DK607587A
Authority: DK
Inventors: Leif Tilly
Original assignee: Leif Tilly
Priority date: 1986-03-24
Filing date: 1987-11-19
Publication date: 1994-07-18
Also published as: NO874891L; NO171954B; DE3770816D1; NO874891D0; NO171954C; DK607587D0; DK607587A

Description

i DK 168943 B1in DK 168943 B1

Opfindelsen angår en fremgangsmåde til tilførsel af et elektrisk ledende, flydende medium, f .eks. maling, fra et lagersystem over en fødeledning til en forbrugsstation, hvori der er en elektrostatisk opladelig 5 fordelings indretning, såsom en sprøjtepistol, til f. eks. maling af emner, hvor mediet tilføres et mellemlager, som udgør en del af fødeledningen mellem lagersystemet og forbrugerstationen, og hvor fødeledningen er indrettet til elektrisk og fysisk at afbrydes mellem lagersy-10 stemet og forbrugerstationen ved hjælp af en afbrydeenhed, hvormed mediet fra lagersystemet via en første fødeledning pumpes til en første, lukket ventildel, som udgør en del af afbrydeeenheden, hvis anden ventildel, som er forbundet med en anden fødeledning, ved sammen-15 kobling med nævnte første ventildel etablerer forbindelse for mediet gennem fødeledningerne, og hvor mediet under perioden for ventildelenes sammenkobling pumpes til mellemlageret, hvorved den elektrostatiske opladning afbrydes, hvorhos mediet efter frakobling af 20 ventildelene underkastes et tryk i mellemlageret og under elektrostatisk opladning tilføres fordelingsindretningen. Opfindelsen angår yderligere en indretning til udøvelse af fremgangsmåden.The invention relates to a method for supplying an electrically conductive liquid medium, e.g. paint, from a storage system over a feed line to a consuming station, in which there is an electrostatically rechargeable distribution device, such as a spray gun, for, for example, painting items where the medium is supplied to an intermediate storage which forms part of the feed line between the storage system and the supply station, and wherein the supply line is arranged to be electrically and physically disconnected between the storage system and the consumer station by means of a switching unit, by which the medium from the storage system is pumped via a first supply line to a first closed valve part which forms part of the switching unit if a second valve member connected to a second feed line by coupling with said first valve member establishes connection for the medium through the feed lines, and during which the medium of the valve member interconnection is pumped to the intermediate storage, whereby the electrostatic charge is disconnected, whereupon the medium is disconnected. The 20 valve parts are subjected to pressure in the intermediate bearing and during electrostatic charging, the distribution device is supplied. The invention further relates to a device for carrying out the method.

Anvendelsen af vandbaserede malinger i forbindelse 25 med elektrostatisk ladning har medført, at sikkerhedsaspekterne er kommet i fokus, da der kan forekomme kortslutninger mellem den højspændte elektrostatiske ladning i malesprøjten og det jordede malingsledningssystem.The use of water-based paints in connection with electrostatic charge has brought the safety aspects into focus as short circuits may occur between the high-voltage electrostatic charge in the paint sprayer and the grounded paint pipe system.

30 Forskellige indretninger er tidligere kendt for at forhindre sådanne potentialforskelle i at opstå. Alle disse kendte fremgangsmåder virker efter det såkaldte "regndråbeprincip", der er ensbetydende med, at lagerbeholderen, hvori malingen er lagret, er adskilt fra den 35 elektrostatisk ladede malesprøjte og leverer malingen DK 168943 B1 2 dråbe for dråbe over en så stor luftspal te, at der ikke kan optræde noget overslag. Disse indretninger har imidlertid den ulempe, at de har meget begrænset kapacitet og ikke tillader kontinuerlig sprøjtemaling, 5 især når der er tale om større maleobjekter, såsom f.eks. bilkarosserier.30 Various devices are previously known to prevent such potential differences from occurring. All of these known methods operate according to the so-called "raindrop principle", which means that the storage container in which the paint is stored is separated from the electrostatically charged paint syringe and delivers the paint drop to such a large air gap tea, that no estimate can occur. However, these devices have the disadvantage that they have very limited capacity and do not allow continuous spray painting, especially in the case of larger painting objects such as e.g. car bodies.

Et andet problem ved konventionelle maleeanlæg er vanskeligheden ved at skifte maling i det korte tidsrum, der kræves for at fjerne det behandlede objekt og 10 placere et nyt maleobjekt indenfor malesprøjtens aktionsradius. Eftersom maling mere og mere udføres ved hjælp af robotter, foretrækkes det, at malingsændringen sker, uden at det er nødvendigt at skifte sprøjteudstyr.Another problem with conventional painting systems is the difficulty of changing the paint for the short amount of time required to remove the treated object and placing a new paint object within the spray radius of action. As paint is increasingly done with the help of robots, it is preferable that the paint change occurs without the need to change spraying equipment.

Fra beskrivelsen til US-patentskrift nr. 4 313 475 15 kender man en indretning af den art der er angivet i indledningen til hhv. krav 1 og krav 3. En ulempe ved denne kendte teknik skal ses i, at der som mellemlager anvendes en volumenfast beholder, hvori der til overføring af maling til sprøjtepistolen vedvarende op-20 retholdes tryk med trykgas, fortrinsvis trykluft. Denne trykluft virker passivt på malingen som først presses ud, når en nedstrøms placeret ventil åbnes. Dette indebærer, at det er meget svært, for ikke at sige umuligt helt at tømme mellemlageret i det tilfælde, hvor 25 man eksempelvis ønsker at skifte maling, eftersom trykket ikke vil kunne fjerne maling fra beholdervæggen.From the specification of U.S. Patent No. 4,313,475, a device of the kind disclosed in the preamble of Claim 1 and Claim 3. A disadvantage of this known technique is that a volume-proof container is used as an intermediate storage in which, for transferring paint to the spray gun, constant pressure is maintained with compressed gas, preferably compressed air. This compressed air acts passively on the paint which is only pressed out when a downstream valve is opened. This implies that it is very difficult, not to say impossible, to completely empty the intermediate layer in the case where, for example, one wishes to change paint, since the pressure will not remove paint from the container wall.

Denne kendte teknik egner sig således til kontinuerlig sprøjtemaling men ikke til situationer, hvor der ønskes hyppig skift af maling til små serier.This prior art is thus suitable for continuous spray painting but not for situations where frequent change of paint to small series is desired.

30 En anden ulempe ses i, at der med trykgas eller trykluft er stor risiko for kemisk påvirkning på maling (farveændring) og stor risiko for at små luftbobler presse ud, hvilket ligeledes kan bevirke farveændring og iøvrigt er yderst farligt, når maling indeholder DK 168943 B1 3 letantændelige opløsningsmidler, og når den elektrostatiske ladning kan nå op på f.eks. 100 kV.30 Another disadvantage is seen that with compressed gas or compressed air there is a high risk of chemical effects on paint (color change) and a high risk of small air bubbles squeezing out, which can also cause color change and is also extremely dangerous when paint contains DK 168943 B1 3 flammable solvents and when the electrostatic charge can reach e.g. 100 kV.

Opfindelsen tager sigte på at afhjælpe sådanne ulemper og med henblik herpå er en fremgangsmåde af den 5 indledningsvis angivne art ejendommelig ved, at mellemlagerets volumen indstilles svarende til det fornødne volumen af mediet til behandling af et emne henholdsvis en gruppe emner, før tilførsel af mediet til mellemlageret, og at der til overføring af mediet fra mellem-10 lageret til forbrugsstationen udvirkes aktiv udpumpning af det i mellemlageret værende medievolumen.The invention aims to remedy such disadvantages and for this purpose, a method of the kind mentioned initially is characterized in that the volume of the intermediate storage is adjusted to the required volume of the medium for treating a workpiece and a group of workpieces, respectively, before supplying the medium to the workpiece. the intermediate storage, and that for the transfer of the medium from the intermediate storage to the consumption station, active pumping out of the medium volume in the intermediate storage is effected.

Herved opnås, at den elektrostatiske ladning i sprøjtedysen ikke overføres til maleanlæggets lagersystem. Desuden er funktionen uafhængig af den forholdsvis 15 lange tid, der kræves til dielektrisk overføring af malingen og man er i stand til at skifte en maling på enkel og meget hurtig måde. Bilfabrikantens krav kan f.eks. være, at det før maling af hvert enkelt bilkarosseri skal være muligt at foretage en malingsændring.In this way, the electrostatic charge in the spray nozzle is not transferred to the painting system's storage system. Furthermore, the function is independent of the relatively long time required for dielectric transfer of the paint and one is able to change a paint in a simple and very fast way. The car manufacturer's requirements can, e.g. be that it is possible to make a change of paint before painting each car body.

20 Den som mellemlager fungerende pumpe har den fordel, at beholdervæggen så at sige skrabes ren for maling, og at denne maling ikke kommer i kontakt med trykmediet. Endvidere sikrer opfindelsen at der opnås fuldstændig regulering af tryk og farvemængde.The intermediate storage pump has the advantage that the container wall is, so to speak, scraped clean of paint and that this paint does not come into contact with the pressure medium. Furthermore, the invention ensures that complete control of print and color quantity is achieved.

25 Opfindelsen angår også en indretning til udøvelse af fremgangsmåden ifølge opfindelsen, hvilken indretning til tilførsel af et elektrisk ledende, flydende medium, f.eks. maling fra et lagersystem over en fødeledning til en forbrugsstation og omfattende en elektrostatisk 30 opladelig fordelings indretning, såsom en sprøjtepistol, til f.eks. maling af emner, og hvor der i ledningen mellem lagersystemet og forbrugsstationen findes en afbrydeenhed, indrettet til elektrisk og fysisk at afbryde ledningen, hvilken afbrydeenhed indbefatter en 35 første ventildel, som udgør en del af lagersystemets DK 168943 B1 4 føde ledning, og en anden ventildel, som udgør en del af fØdeledningen til fordelerindretningen, samt en trykcylinder til fluidtæt sammenkobling af ventildelene og til elektrisk og fysisk frakobling af ventildelene, 5 hvilken trykcylinder er således indrettet, at der ved frakobling dannes en luftspalte mellem ventildelene, hvorhos der nedstrøms for afbrydeenheden i den anden ledning findes et mellemlager, hvis volumen i det mindste svarer til behandlingen af ét emne, samt en 10 styreanordning indrettet til under ventildelenes sammenkoblingsfase at afbryde den elektrostatiske opladning, og hvor fødeledningen opstrøms for afbrydeenheden kan kobles til en kilde for et skyllemedium til skylning af medieoverføringsvejen er ejendommelig ved, 15 at mellemlageret udgøres af en pumpe med et organ til volumenindstilling og til aktivt at presse indholdet i mellemlageret ud.The invention also relates to a device for carrying out the method according to the invention, which device for supplying an electrically conductive liquid medium, e.g. painting from a storage system over a supply line to a consuming station and comprising an electrostatic rechargeable distribution device, such as a spray gun, for e.g. painting of items, and wherein in the line between the storage system and the consumption station there is a switching unit adapted to electrically and physically interrupt the line, which switching unit includes a first valve part which forms part of the storage system of the storage system and a second a valve member, which forms part of the feeding line for the distributor device, and a pressure cylinder for fluid tight coupling of the valve parts and for electrical and physical disconnection of the valve parts, which pressure cylinder is arranged so that, when disconnected, an air gap is formed between the valve parts where the downstream of the downstream part is cut off. in the second conduit there is an intermediate storage, the volume of which at least corresponds to the processing of one item, and a control device adapted to interrupt the electrostatic charge during the interconnection phase of the valve parts, and where the feed line upstream of the interrupt unit can be connected to a source of a rinsing medium. flushing media transfer The weld is characterized in that the intermediate layer is constituted by a pump with a volume adjusting means and to actively compress the contents of the intermediate layer.

Opfindelsen beskrives i det følgende nærmere under henvisning til tegningen, på hvilken 20 fig- 1 stærkt skematiseret viser et maleanlæg, hvori fremgangsmåden og indretningen ifølge opfindelsen er anvendt, og fig. 2 og 3 viser i større detaljer snit gennem ventildele af en brydeenhed, der danner en del af 25 maleanlægget.BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be described in more detail with reference to the accompanying drawing, in which: FIG. 2 and 3 show in greater detail sections through valve portions of a switching unit forming part of the painting system.

I fig. 1 henviser henvisningsbetegnelsen 11 til et lagersystem, og 12 er en forbrugerstation, der begge danner dele af et fortrinsvis computerstyret maleanlæg, hvor computeren er betegnet 13.In FIG. 1, the reference numeral 11 refers to a storage system, and 12 is a consumer station, both of which form part of a preferably computer controlled painting system where the computer is designated 13.

30 Lageranlægget 11 indeholder en lagertank 14 for f.eks. en vandbaseret maling, en skyllemiddelbeholder 15, en trykluftskilde 16 og et udløsningsorgan 17 koblet til denne og udformet som et pneumatisk drevet stempel 18 og en cylinder 19. Stempelstangen 18 bærer ved sin 35 frie ende den ene del 20 af en todelt ventil 21, hvis DK 168943 B1 5 anden del 22 danner en del af forbrugerstationen 12. Ventilen 21, der er indrettet som en brydeenhed, har en af sine dele 20 koblet til en ledning 25, der er afgrenet til lagertanken 14 og til skyllemiddeltanken 5 15 over en pumpe 23, 24 for hver, medens den anden ventildel 22 er forbundet til en ledning 26 hørende til forbrugerstationen 12.The storage system 11 contains a storage tank 14 for e.g. a water-based paint, a softener container 15, a compressed air source 16, and a release means 17 coupled thereto and configured as a pneumatically driven piston 18 and a cylinder 19. The piston rod 18 carries at its free end one portion 20 of a two-part valve 21 if DK 168943 B1 5 second part 22 forms part of consumer station 12. Valve 21 arranged as a switching unit has one of its parts 20 connected to a line 25 which is branched to storage tank 14 and to the rinse tank 5 15 over a pump 23, 24 for each, while the second valve portion 22 is connected to a conduit 26 of the consumer station 12.

Strømningsmæssigt ovenfor brydeenheden 21's ventildel 22 er der indrettet en kontraventil 27 i 10 ledningen 26, en doseringspumpe 28 og en fordelingsindretning 29, f.eks. en sprøjteindretning, der har en sprøjtedyse 30. Doseringspumpen 28, der udgøres af en stempelpumpe med indstilleligt deplacement, er indrettet således, at puumpecylinderen kan anvendes som mellem-15 lager, der har et så stort volumen, at den lagrede mængde strækker f.eks. til en behandling, maling, af et behandlingsobjekt. Forbrugerstationen 12 indeholder yderligere en højspændingskilde 31, der kan skabe et elektrostatisk kraftfelt inde i sprøjteindretningen 29.Flowwise above the valve portion 22 of the breaker unit 21, a check valve 27 is arranged in the line 26, a metering pump 28 and a distribution device 29, e.g. a spray device having a spray nozzle 30. The metering pump 28, which is constituted by a piston pump with adjustable displacement, is arranged so that the pump cylinder can be used as an intermediate storage having such a large volume that the stored quantity extends e.g. . for a treatment, paint, of a treatment object. The consumer station 12 further includes a high voltage source 31 which can create an electrostatic force field within the syringe device 29.

20 Til denne er der yderligere forbundet en trykluftsledning 32 fra trykluftkilden 16 og en luftudgang 33 og en afløbsledning 34, der munder ud i en beholder 35 for brugt skyllevaske.To this is further connected a compressed air conduit 32 from the compressed air source 16 and an air outlet 33 and a drain conduit 34 which opens into a container 35 for used rinsing.

Doseringspumpen 28 drives af trykluft over led-25 ningen 36 fra trykluftkilden 16. Doseringspumpen 28 har yderligere organer til at frembringe turbulens, hvilke organer f.eks. kan være en propel 37, der drives af en motor 38.The metering pump 28 is driven by compressed air over the conduit 36 from the compressed air source 16. The metering pump 28 has additional means for producing turbulence, which means e.g. may be a propeller 37 driven by a motor 38.

Det første funktionsmoment i maleanlægget er, at 30 computeren 13 eller en tilsvarende styremekanisme giver et signal til trykluftkilden 16 for at aktivere udløseren 17, således at stemplet 18 forskydes i cylinderen 19, og brydeenheden 21's ventildele 20, 22 forskydes imod hinanden, således at der bevirkes en 35 sammenkobling af ledningerne 25 og 26. Som det ses i DK 168943 B1 6 fig. 2 og 3 er de to ventildele begge forsynet med et fjederbelastet ventillegeme 39, 40, der i ventildelene 20, 22's sammenkoblede stilling trykkes imod hinanden og derved åbner gennemgangen for mediet. Når sammen-5 koblingen er foretaget, starter pumpen 23 og pumper den valgte farvemaling gennem ledningerne 25 og 26 til doseringspumpen 28, hvori stempelstangen ved computeren 13's foranstaltning har indtaget en sådan stilling, at en under hensyntagen til maleobjektet passende mængde 10 leveres til pumpecylinderen, der virker som et mellemlager. Pumpen 23 standses, når mellemlageret er blevet fyldt, og brydeenhedenn 21 trækkes fra hinanden, således at elektrisk overgang er umulig også ved luftoverslag. Højspændingsaggregatet 31 startes af computeren, således 15 at der skabes et elektrostatisk felt i sprøjteindretningen 29, hvorpå trykluft fra trykluftkilden 16 via en impuls fra computeren 13 føres til den negative side af doseringspumpen 28, således at maling føres op til sprøjteindretningen 29 og ud igennem sprøjtedysen 30.The first function of the grinding system is that the computer 13 or a corresponding control mechanism gives a signal to the compressed air source 16 to activate the trigger 17, so that the piston 18 is displaced in the cylinder 19 and the valve parts 20, 22 of the switching unit 21 are displaced against each other. a connection of the wires 25 and 26. is effected as seen in DK 168943 B1 6 fig. 2 and 3, the two valve parts are both provided with a spring-loaded valve body 39, 40 which is pressed against each other in the coupled position of the valve parts 20, 22 and thereby opens the passage for the medium. When the coupling is made, the pump 23 starts and pumps the selected color paint through the lines 25 and 26 to the metering pump 28, in which the piston rod by the measure of the computer 13 has taken such a position that a suitable quantity 10 is delivered to the pump cylinder, taking into account the grinding object. that acts as a middle layer. The pump 23 is stopped when the intermediate storage has been filled and the breaker unit 21 is pulled apart, so that electrical transition is impossible even in the case of air changes. The high voltage assembly 31 is started by the computer so as to create an electrostatic field in the syringe device 29, whereby compressed air from the compressed air source 16 is supplied via a pulse from the computer 13 to the negative side of the metering pump 28, so that paint is fed to the syringe device 29 and out through the syringe nozzle. 30th

20 Da mængden af maling i doseringspumpen 28 indstilles således, at der netop er nok til maling af det behandlingsobjekt, der er tale om, vil pumperummet 42 i hovedsagen tømmes. Højspændingsaggregatet 31 aflukkes derpå, og brydeenhedens to ventildele 20 og 22 sammen-25 kobles derpå atter, hvorefter næste operationscyklus kan påbegyndes.Since the amount of paint in the metering pump 28 is adjusted so that there is just enough to paint the treatment object in question, the pump compartment 42 will essentially be emptied. The high voltage assembly 31 is then shut off and the two valve parts 20 and 22 of the switching unit are then interconnected, after which the next cycle of operation can be started.

Hvis man ønsker en malingsændring forud for næste overføring af ny maling, starter computeren 13 pumpen 24, der fra skyllemiddelbeholderen 14 pumper skyllevæske 30 gennem hele lagersystemet og forbrugersystemet, hvor de turbulensskabende organer 37 i doseringspumpen 28 kan give skyllevasken en sådan bevægelse, at malingen i denne opløses og skylles ud. Efter at skyllemediet har passeret sprøjteindretningen 29 bortledes det dels 35 gennem sprøjtedysen 30 og dels gennem skyllemiddelled-If a paint change is desired prior to the next transfer of new paint, the computer 13 starts the pump 24 pumping from the rinse aid container 14 flushing liquid 30 throughout the storage system and the consumer system, where the turbulence generating means 37 in the metering pump 28 can cause the rinse wash to move this is dissolved and rinsed out. After the rinse medium has passed the spray device 29, it is discharged partly 35 through the spray nozzle 30 and partly through the rinse aid line.

Claims

Furthermore, the metering point may be of a different type and the intermediate storage may be a separate container.

A method of supplying an electrically conductive liquid medium, e.g. paint, from a storage system (11) over a supply line (25, 26) to a consuming station (12), wherein there is an electrostatically rechargeable distribution device (29) such as a spray gun, for example. painting items in which the medium is fed to an intermediate storage (42) which forms part of the supply line (26) 20 between the storage system (11) and the consumer station (12), and wherein the supply line is arranged to be electrically and physically interrupted between the storage system (11) and the consumer station (12) by means of a switching unit (21) by which the medium from the storage system (11) is pumped via a first 25 supply line (25) to a first closed valve part (20) which forms part of the switching unit (21), the second valve member (22) connected to a second feed conduit (26), by interconnecting with said first valve member, establishes a connection for the medium through the 30 feed lines (25, 26) and wherein the medium during the period of the valve portion (20, 22) interconnects pumped to the intermediate bearing (42), thereby interrupting the electrostatic charge, whereby the medium, after disconnecting the valve parts (20, 22), is subjected to a pressure in the intermediate bearing (42) and during electrostatic charging is applied in the device (29), characterized in that the volume of the intermediate storage (42) is adjusted corresponding to the required volume of the medium for processing a 5 item or a group of items, respectively, before supplying the medium to the intermediate storage, and for transferring the medium from the intermediate storage to the consumption station (12) causes active pumping out of the medium volume in the medium storage.

A method according to claim 1, characterized in that, by changing medium and prior to transferring new medium, rinsing of the media transfer path through the storage system (11) and the second feed line (26) to the intermediate storage is effected from which the rinse medium is actively pumped out. and passed through the consuming station (12).

3. Device for supplying an electrically conductive liquid medium, e.g. painting from a storage system (11) over a supply line (25, 26) to a consuming station (12) in accordance with the method of claim 1, and comprising an electrostatically rechargeable distribution device (29) such as a spray gun, for example. . painting of items and wherein in the line (25, 26) between the storage system (11) and the consuming station (12) 25 there is a switching unit (21) adapted to electrically and physically interrupt the line, which switching unit (21) includes a first valve part (20) which forms part of the feed line (25) of the storage system (11) and another valve part (22) which forms part of the feed line (26) 30 for parts of the device (29), and a pressure cylinder (17) for fluid tight coupling of the valve parts (20, 22) and for electrical and physical disconnection of the valve parts, which pressure cylinder (17) is arranged such that, when disconnected, an air gap is formed between the valve parts 35 (20, 22) downstream of the switching unit ( 21) DK 168943 B1 9 in the second conduit (26) contains an intermediate bearing (42), the volume of which corresponds at least to the processing of one item, and a control device (13) arranged to interrupt the coupling phase of the valve parts (20, 22). the 5 electrostatic charge, and h our feed line (25, 26) upstream of the interrupt unit (21) can be coupled to a source (15) of a rinse medium for flushing the media transfer path, characterized in that the intermediate storage (42) is constituted by a pump (28) with a means 10 (41). ) for volume setting and to actively squeeze out the contents of the intermediate layer.

Device according to claim 3, characterized in that the pump (28) is a metering pump whose piston (41) has adjustable pump stroke and thus constitutes both the volume adjusting means and the means for actively pressing out the contents of the intermediate storage.

Device according to claim 3 or 4, characterized in that the metering pump has means (37, 38) for inducing turbulence in the pump chamber (42).