DE4117613A1 - SPRAY COATING DEVICE - Google Patents

Abstract

A spray coating device is disclosed for automatically applying a liquid coating material, in particular on motor vehicle bodies, by means of a sprayer (2) for several coating materials. The device has a flow path (14) for the coating materials that extends from a coating material exchanger (10) to the sprayer (2). When the coating material is exchanged, the flow path (14) can be washed with a fluid. The flow path (14) for the coating material has a first switching device (38) that allows it to be subdivided for washing purposes into at least two sections (40, 42) that can be washed separately but at the same time. The first section (40) extends from the coating material exchanger (10) to the first switching device (38) and the second section (42) extends from the first switching device (38) to the spraying member (44).

Description

The invention relates to a spray coating device according to the preamble of claim 1.

Such a spray coating device is from DE-PS 32 01 930 C2 known. During the coating process flows coating material (colored or transparent, Color, varnish) of one or more Coating material containers into one Coating material changer and from this one Flow path to an atomizer device that Coating material on a to be coated Object sprays. If the coating material changer no more coating material is supplied  Flow path still filled with coating material. So that this coating material is not lost, an additional fluid (air, but preferably liquid, especially solvent) starting from the coating material changer up to Atomizing device of the atomizing device from the Flow path pushed out and from the Atomizing device on the to be coated Object sprayed. The remaining residues in the Flow path will be through the same or a different one Fluid through a continuous or intermittent fluid surge from the flow path expelled. These details can also be found at present invention application. More details are the aforementioned DE-PS 32 01 930 C2.

The invention is intended to solve the problem for the cleaning of the flow path required time Change from one coating material to another Coating material and the amount of it to reduce the required solvent. At the same time the task can be solved in coating breaks, if then with another or the same Coating material is continued in a shorter than previously required To be able to clean the atomizer alone less solvent than was previously required.

This object is achieved according to the invention by characterizing features of claim 1 solved.

Further features of the invention are in the claims contain.  

The invention is described below with reference to the drawing using a preferred embodiment as an example described.

The drawing shows a spray coating device according to the invention for the automatic application of liquid coating material to in particular motor vehicle bodies by means of an atomizing device 2 for several, for example three, coating materials, in particular paints in a pressure vessel 4 , 6 and 8 . The atomizing device 2 contains known means for electrostatically charging the coating material. Depending on the number of different coating materials, a coating material changer 10 , hereinafter called color changer, contains, for example, six valves, preferably 2/2-way valves 12/1 , 12/2 , 12/3 , 12/4 , 12/5 and 12 / 6 , so that, depending on the open directional valve, the coating material in question reaches the atomizing device 2 via a flow path 14 . In the flow path 14 is effective for all coating materials pressure regulator 16, which is hereinafter referred to as color-pressure regulator 16th For simplicity, it is assumed that a first color, a second color pressure vessel 8, a third color and is in the pressure vessel 4 in the pressure vessel 6, in a further pressure vessel 18, a solvent. A compressed air source 20 is of the color changer 10 to the flow path 14 fluidly connected via a check valve 22/1 and a 2/2-way valve 12/4. The solvent of the pressure vessel 18 can be connected in terms of flow to the flow path 14 via a solvent pressure regulator 24/1 , a check valve 22/2 and a 2/2-way valve 12/5 of the color changer 10 . Furthermore, the solvent pressure vessel 18 can be connected in terms of flow to the flow path 14 via a pressure regulator 24/2 , a check valve 22/3 and a 2/2-way valve 12/6 of the color changer 10 . In addition, the solvent pressure vessel 18 can be connected in terms of flow via a pressure regulator 24/3 and a subsequent check valve 22/4 to a 2/2-way valve 12/7 of a secondary flushing device 30 . The secondary flushing device 30 also contains a 2/2-way valve 12/8 , which is connected in terms of flow to a compressed air source 20 via a check valve 22/5 . The outputs 32 and 34 of the two 2/2-way valves 12/7 and 12/8 are connected to one another in terms of flow and connected to a fluid connection 36 of a first switching device 38 . The first switching device 38 is preferably a 3/2-way valve. The first switching device 38 divides the flow path 14 into a first path section 40 leading from the color changer 10 to the first switching device 38 and a second path section 42 leading from the first switching device 38 , from its flow connection 36 , to the atomizing element 44 of the atomizing device 2 . The atomizing member 44 is preferably a rotating bell. A measuring cell 46 is located in the first path section 40 . The 3/2 way valve of the first switching device 38 connects the first way section 40 in terms of flow with the second way section 42 in the switching position shown. In this switching position of the first switching device 38 , paint can be drawn from one of the pressure containers 4 , 6 or 8 via the relevant valve 12/1 or 12/2 or 12/3 of the color changer 10 to the first path section 40 and from there via the first switching device 38 and the the subsequent second path section 42 of the flow path 14 to the atomizing element 44 of the atomizing device 2 . When all the valves 12/1 , 12/2 and 12/3 of the different colors are closed after this supply of paint , a paint-liquid column remains in the flow path 14 ( 40, 42 ). This can be pushed out of the flow path 14 by solvent from the pressure vessel 18 via one of the two regulators 24/1 and 24/2 and the subsequent valves 12/5 or 12/6 of the color changer 10 until the end of the ink column and so that there is only a small color residue immediately in front of the atomizing element 44 . The atomizer device 2 contains a second switching device 50 in the form of two valves 52 and 54 . One valve 52 is located in the second path section 42 immediately upstream of the atomizing element 44 , and the mentioned column end of the ink column pushed out lies on the short intermediate piece 56 between this valve 52 and the atomizing element 44 . The other valve 54 of the second switching device 50 connects the second path section 42 directly upstream of the one valve 52 to a second return line 58 , which leads to a collecting container 60 . During the conveyance of coating material through the flow path 14 to the atomizing member 44 , and also during the expulsion of the material column remaining after the coating material conveyance in the flow path 14 , one valve 52 is open and the other valve 54 of the second switching device 50 is closed. Furthermore, with this coating material feed and during the ejection of the remaining column of material after its feed, the two valves 12/7 and 12/8 of the secondary flushing device 30 are closed. The coating material and the solvent are conveyed by compressed air sources 20 connected to them.

Was when no coating material is fed to the atomizer device 2, and the remaining in the flow path 14 remaining coating material column in the manner pushed out of her, the flow path 14 must be cleaned of coating material remains. For this purpose, it is possible to remove solvent from the pressure vessel 18 via one or the other of the two pressure regulators 24/1 and 24/2 and one of the valves 12/5 or 12/6 which adjoin the flow into the first path section 40 and from this via the first Switching device 38 also to promote through the second path section 42 . Depending on the design of the atomizing device 2 , the solvent can escape through the one valve 52 of the second switching device 50 on the atomizing element 44 , or can preferably be conveyed into the collecting container 60 when the valve 52 is closed and another valve 54 of the second return line 58 is open. To save time and solvent for this cleaning process, however, according to the invention, the 3/2-way valve of the first switching device 38 is switched to another position, a so-called "rinsing" position. In this “purging” position, the two path sections 40 and 42 are no longer connected to one another in terms of flow via the fluid connection 36 of the first switching device 38 , but are separated from one another in the first switching device 38 . Instead, in this "rinsing" operating position, the first path section 40 is connected via the first switching device 38 to a first return line 62 , which likewise leads into the collecting container 60 . As a result, the solvent (or another rinsing agent) which is conveyed from the color changer 10 through the first path section 40 to the first switching device 38 does not get into the second path section 42 , but directly from the first switching device 38 into the collecting container 60 . At the same time, while one valve 52 of the atomizing device 2 is opened and the other valve 54 is closed, the valves 12/7 and 12/8 of the secondary flushing device 30 are alternately opened and closed, and as a result a solvent (or another flushing agent) from the pressure vessel 18 via the pressure regulator 24/3 and the 2/2-way valve 12/7 and next time compressed air from the compressed air source 20 via the 2/2-way valve 12/8 of the secondary flushing device 30 at the fluid connection 36 of the first switching device 38 into the upstream beginning of the second path section 42 and conveyed through this, whereby this solvent or alternately the air reaches the collecting container 60 via the valve 54 of the second switching device 50 . One valve 52 is thus always closed and the other valve 54 of the second switching device 50 is always open. To expel coating material residues in the short section 56 between the one valve 52 and the atomizing element 44 , the one valve 52 can be briefly opened and at the same time the other valve 54 can be closed, so that then a shock of solvent and / or air from the secondary flushing device 30 the second path section 42 is dispensed via the atomizing element 44 .

According to the invention, the flow path 14 is thus divided into two path sections 40 and 42 during the cleaning process, which are preferably each approximately of the same length, at least each path section should still have a substantial length. If the flow path 14 is halved on two path sections, the time required for rinsing or cleaning the two path sections is also halved if this cleaning or rinsing takes place in parallel, that is to say simultaneously, according to the invention. At the same time, the consumption of cleaning agent or solvent is reduced, since the cleaning effect is greater on short distances than on long distances and less soiled cleaning material or solvent is more receptive to the paint to be cleaned.

The process sequence of the spray coating device according to the invention is described in detail below:
coat with the first color from the pressure vessel 4 ;
Close color valve 12/1 of color changer 10 ;
Open the solvent valve 12/5 and supply the solvent from the pressure vessel 18 with a solvent pressure that is adapted to the viscosity of the coating material, the solvent pressure in the flow path 14 decreasing as the residual coating material column decreases;
with this solvent push the paint column through the flow path 14 until the paint column end is just before the atomizing element 44 ;
Close solvent valve 12/5 of color changer 10 ;
Solvent pressure regulator 24/1 switch to the pressure required to flush with solvent (this also adjusts the amount of solvent);
at the same time set the color pressure regulator 16 to the maximum value so that the solvent can flow freely;
simultaneously switching the 3/2-way valve of the first switching device 38 , so that no solvent can flow from the color changer 10 via the first switching device 38 to the atomizing device 2 , but rather the flow path for solvent and air from the color changer via the first switching device 38 and the first return line 62 is open in the receptacle 60 ;
at the same time close the atomizer valve 52 of the second switching device 50 in the downstream end section of the second path section 42 ;
simultaneously opening the flushing valve 54 of the second switching device 50 in the atomizing device 2 so that the second return line 58 into the collecting container 60 is open;
then pulsating alternating supply of air and solvent

• a) Air from the air source 20 via the valve 12/4 of the color changer 10 or solvent from the pressure vessel 18 via the solvent pressure regulator 24/2 and the valve 12/6 of the color changer 10 through the first path section 40 of the flow path 14 to the first switching device 38 and from this directly through the first return line 62 into the collecting container 60 , and at the same time in parallel
• b) from the secondary flushing device 30 air from the air source 20 via the 2/2-way valve 12/8 and alternately solvent from the pressure vessel 18 via the solvent pressure regulator 24/3 and the 2/2-way valve 12/7 the secondary flushing device 30 to the fluid connection 36 and thus in the beginning of the second Wegab section 42 and through this second Wegab section 42 , at the end of which it comes with the valve 52 closed and the valve 54 open via the second secondary line 58 into the collecting container 60 ;
  the amount of solvent in the second way section 42 is set by the solvent pressure regulator 24/3 (fixed value or variable depending on the flushability of the coating material to be washed and / or variable depending on the time);

then switch off the solvent supply;
then the first section

40

from Blow out the color changer with air and the second one Path section

42

from the secondary flushing device

30th

blow out with air;
Turn off air;
prepare the supply of another coating material or a different color by following these steps:
Switching back the first switching device

38

on the position shown in the drawing, at which they the two sections of the path

40

and

42

of Flow path

40

with each other in terms of flow connects, the collecting container

60

flow is separated, and the secondary flushing device

30th

is switched off;
the color pressure regulator

16

remains at maximum pressure setting;
the flush valve

54

the atomizing device

2nd

remains open and the atomizer valve

52

The second Switching device

50

remains closed;
open the valve

12/1

or

12/2

or

12/3

of Color changer

10th

for the pressure vessel

4th

,

6

or

8th

the selected color in question;
the selected color is until just before the flush valve

54

the second switching device

50

through the Flow path

14

promoted, and then switches in this Moment the color pressure regulator

16

from its maximum Setting to the for the coating process required color printing and the color is through that Flush valve still open

54

(Atomizing Valve

52

closed) until just behind this Valve

54

promoted;
Closing the flush valve

54

;
open the atomizing valve

52

The second Switching device

50

, and promote the color through this spray valve

52

through either only to the connector

56

between this spray valve

52

and the atomizer

44

or completely until to the atomizer

44

, depending on whether the Spray coating process only prepared (paint press) or the spray coating process already should be carried out, i.e. color towards you coating object to be sprayed.  

According to a special embodiment of the invention, it is possible to provide a second coating material changer 210 for further different types of coating material and to connect it via a further first path section 240 and a further first switching device 238 to the same flow connection 36 at the beginning of the second path section 42 , so that then either a color changer 10 and one of the first path section 40 or the other color changer 210 and its first path section 240 are connected to the second path section 2 and thus can use the latter together alternately. The further first switchover device 238 can in turn be formed by a 3/2-way valve and can be connected to the collecting container 60 in terms of flow by a third return line 262 . In this way, interruptions in operation are avoided even when a large number of different coating materials are used alternately and in between individual material strands or pressure containers containing coating material have to be exchanged or cleaned.

An advantage of the invention is that by dividing the flow path into the sections 40 and 42 or 240 and 42 it is possible to clean the atomizer device 2 in a short time with little solvent using the secondary flushing device 30 , without cleaning the first path section 40 . This is expedient if, when using the same coating material, cleaning only the atomizer device 2 is required, for example during breaks in operation.

If so-called water-based paint is used as the coating material, it is also possible within the scope of the invention to provide a further flushing device 330 corresponding to the construction of the secondary flushing device 30 , with which it is possible, if necessary, only the atomizing member 44 of the atomizing device 2 with solvent and / or air to clean.

Claims (9)

1.spray coating device for the automatic application of liquid coating material to motor vehicle bodies in particular by means of an atomizing device for a plurality of coating materials, with a flow path for the coating materials from a coating material changer to the atomizing device, the flow path being flushable with fluid when changing the coating material, characterized in that the flow path ( 14 ) of the coating material contains a first switching device ( 38 ) with which it can be subdivided into at least two path sections ( 40 , 42 ) for the rinsing process, which are separate but can be rinsed at the same time, of which the first path section ( 40 ) changes from the coating material ( 10 ) to the first switching device ( 38 ) and the second path section ( 42 ) extends from the first switching device ( 38 ) to the atomizing element ( 44 ). 2. Spray coating device according to claim 1, characterized in that the first path section ( 40 ) and the second path section ( 42 ) each have their own fluid supply device ( 10 , 30 ) for the supply of the fluid used for flushing. 3. Spray coating device according to claim 2, characterized in that the fluid supply device of at least the second path section ( 42 ) is an alternately a plurality of air or solvent shocks device ( 30 ). 4. Spray coating device according to one of claims 1 to 3, characterized in that the end of the first path section ( 40 ) by means of the first switching device ( 38 ) via a first return line ( 62 ), and the atomizer device ( 2 ) by means of a second switching device ( 50 ) can be connected in terms of flow for the rinsing process via a second return line ( 58 ) to a collecting container ( 60 ), and that the two switching devices ( 38 , 50 ) separate the two return lines ( 62 , 58 ) from the two path sections ( 40 , 42 ) in terms of flow and instead release the full flow path ( 14 ) continuously for coating material when they are switched from "rinsing" back to "coating". 5. Spray coating device according to claim 4, characterized in that the second switching device ( 50 ) can optionally be switched from "rinsing" to "coating" and then vice versa, while the first switching device ( 38 ) is switched to "rinsing". 6. Spray coating device according to one of claims 1 to 5, characterized in that the first switching device ( 38 ) is a switchable multi-way valve. 7. Spray coating device according to one of claims 1 to 6, characterized in that the second switching device ( 50 ) consists of two valves ( 52 , 54 ), of which the one valve ( 52 ) in the end portion of the to a spray element ( 44 ) of the atomizer device ( 2 ) leading second path section ( 42 ) is arranged, and from which the other valve ( 54 ) forms the beginning of the second return line ( 58 ), which branches upstream of the one valve ( 52 ) from the second path section ( 42 ). 8. Spray coating device according to one of claims 1 to 7, characterized in that a detergent supply device ( 330 ) for separate supply of detergent to the spray member ( 44 ) of the atomizing device ( 2 ) is provided separately from the flow path ( 14 ) of the coating material. 9. Spray coating device according to one of claims 1 to 8, characterized by at least one second coating material changer ( 210 ) for a plurality of coating materials, the flow path ( 14 ) for its coating materials through its own first path section ( 240 ) from it to a further first switching device ( 238 ) and is formed by the second path section ( 42 ), which can optionally be used for all coating materials from the first switching devices ( 38 , 238 ).