JP2003236442A - Device for supplying coating material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device for supplying a coating material capable of changing color and washing piping between a coating material circulation pipe in which a pig is inserted and a color change valve. <P>SOLUTION: In the device for supplying the coating material, the coating material circulation pipe 41 into which a second pig PG2 is inserted is connected to a switching valve 22a of a color change valve unit 2 provided on the upper stream side of a coater 1. Starting from the upper stream side, a coating material pipe 6 for connecting the switching valve 22a with the coating material circulation pipe 41 has an opening and closing valve 61 for making passage of the coating material supplied from the coating material circulation pipe on and off, a first three-way valve 62 to which a fluid for washing is supplied and a second three-way valve 63 to which a fluid for pushing out is supplied. Both the first three-way valve 62 and the second three-way valve 63 double as a pig station for the first pig PG1. When the color is changed, the coating material pipe 6 is washed with the first pig PG1. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paint supply apparatus preferably applied to a production line of an automobile, and more particularly to a paint supply for color-cleaning a pipe between a paint circulation pipe and a color change valve by using a pig. Regarding the device.

[0002]

2. Description of the Related Art A paint supply device used in a painting line of an automobile includes a paint tank filled with paint of each paint color, a pump for pumping the paint tank, a paint machine (actually, a color change valve). Unit) and a paint pipe that guides the paint to the unit), and the paint tanks, pumps, and paint pipes are installed by the number corresponding to the number of paint colors. Then, by switching the color change valve provided on the upstream side of the coating machine, a paint having a coating color according to the vehicle specifications is sprayed. In this specification, "upstream side" and "downstream side" mean the upstream side in the flow direction of the paint, in other words, the uppermost stream is the paint tank and the lowermost stream is the coating gun.

By providing a common circulating pipe for a plurality of paint colors and passing a movable member called a pig through the paint pipe, the paint of the previous color adhered to the inner wall of the paint pipe is scraped off. It has also been proposed to improve the washability and shorten the color change time.

[0004]

However, in the paint supply system using such a pig, since the pig does not circulate in the pipe between the paint circulation pipe into which the pig is inserted and the color change valve, a plurality of colors are not mixed. You can't change the color even if you try to cope with the paint circulation piping of.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a paint supply device capable of color-cleaning a pipe between a paint circulating pipe into which a pig is inserted and a color change valve.

(1) In order to achieve the above object, according to the present invention, there is provided a paint supply device in which a paint circulation pipe is connected to a switching valve of a color change valve unit provided on the upstream side of a coating machine. An opening / closing valve that turns on and off the passage of the paint supplied from the paint circulation pipe and a cleaning fluid are sequentially supplied to the paint pipe that connects the switching valve and the paint circulation pipe from the upstream side. And a second direction switching valve to which a fluid for extrusion is supplied,
Further, there is provided a paint supply device having a first pig drive means for movably emitting and capturing the first pig in at least the paint pipe between the first direction switching valve and the second direction switching valve. Provided (see claim 1).

In the paint supply device according to the first aspect of the present invention, as described in the third aspect, when the coating of the previous color is completed, first, the extruding fluid is supplied to the second directional control valve and the first
The first pig is moved from the side of the second direction switching valve toward the first direction switching valve by the pig driving means and remains in the paint pipe between the second direction switching valve and the paint circulation pipe. The previous color paint is extruded into the paint circulation pipe through the first pig.

Then, while supplying the cleaning fluid to the first direction switching valve, the first pig driving means moves the first pig from the first direction switching valve side toward the second direction switching valve. Then, the paint pipe between the first direction switching valve and the switching valve is washed.

This makes it possible to clean the pipe between the paint circulating pipe into which the pig is inserted and the color change valve, and as a result, it is possible to apply a plurality of colors to one paint circulating pipe. In particular, since the previous color paint remaining in the paint pipe between the second direction switching valve and the paint circulation pipe is first pushed out to the paint circulation pipe, the amount of waste paint is small, which is advantageous in terms of cost.

The cleaning fluid supplied to the first directional control valve is not particularly limited, but when a solvent-based paint is used, when a cleaning solvent, compressed air, or a water-based paint is used. Is water for cleaning or compressed air.

The first and second directional control valves of the present invention are switching valves capable of switching in at least three directions, and are not limited to three-way valves, and are intended to include four-way valves and the like. In addition to the direction switching function, it is more preferable that the first pig also has a function of firing, capturing, and cleaning (see claim 2). However, in addition to having the functions of firing, capturing, and cleaning the first pig shared by the first and second direction switching valves, the first pig is fired, captured, and cleaned in the vicinity of these direction switching valves. It is within the scope of the present invention to provide a pig station having a function separately. The first pig driving means according to the present invention includes these.

(2) The extruding fluid supplied to the second directional control valve is not particularly limited, but may be compressed air, a cleaning solvent or other various fluids, and one extruding fluid may be supplied. It is also within the scope of the above invention to supply a plurality of types of extrusion fluids.

(3) Although not particularly limited in the above invention, the first directional switching valve is in the vicinity of the paint circulation pipe, the second directional switching valve is in the vicinity of the switching valve,
It is preferable to provide each of them (see claim 4). The term "vicinity" as used herein means that the mechanical elements constituting the piping component are provided at a substantial position where they are physically as close to each other as possible.

By doing so, the amount of the previous color paint that is returned to the paint circulation pipe in the first operation increases and the amount of waste paint further decreases, and the range that can be washed in the next operation becomes longer and the previous color paint The remaining amount and the cleaning time are shortened.

(4) Although not particularly limited in the above invention, it is preferable that a pump for pumping the paint is provided in the paint circulation pipe, and the pump is stopped at the time of color change (see claim 5).

In the first operation at the time of color change, the previous color paint remaining in the paint pipe between the second directional control valve and the paint circulation pipe is pushed out to the paint circulation pipe. At this time, the pump is stopped. Since the paint pressure in the paint circulation pipe decreases,
Even if the extruding fluid supplied to the direction switching valve is low in pressure, the previous color paint can be pushed back smoothly.

(5) Although not particularly limited in the above invention, at the time of coating, the opening / closing valve is opened, and the first directional switching valve and the second directional switching valve cause the coating material in the paint circulating pipe to flow to the switching valve. The position is switched to the position where it passes (see claim 6).

At the time of normal painting, the paint in the paint circulating pipe can be supplied to the color change valve by switching the on-off valve, the first directional switching valve and the second directional switching valve in this way.

[0019]

According to the present invention, the pipe between the paint circulation pipe and the color change valve can be cleaned, and as a result, a plurality of colors can be applied to one paint circulation pipe. be able to. In particular, since the previous color paint remaining in the paint pipe between the second direction switching valve and the paint circulation pipe is first pushed out to the paint circulation pipe, the amount of waste paint is small, which is advantageous in terms of cost. Further, by using the pig type paint pipe, the color changing time can be shortened, and the number of paint pipes or the paint pipe length can be shortened even for a large number of paint color types.

Further, according to the invention described in claim 4, the amount of the previous color paint returned to the paint circulation pipe in the first operation is increased to further reduce the amount of the waste paint, and the range which can be washed in the next operation is Longer, less residual pre-color paint and shorter wash times.

According to the fifth aspect of the invention, since the paint pressure in the paint circulation pipe is reduced by stopping the pump, the extrusion fluid supplied to the second directional control valve has a low pressure. Also, the push back of the previous color paint will be done smoothly.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an overall view showing an embodiment of a paint supply device of the present invention, and FIG. 2 is an enlarged view showing a II portion of FIG. For the sake of convenience, the components shown in FIG. 2 are omitted in FIGS.

First, the paint supply device of the present embodiment has a coating machine 1 (a rotary atomization type coating gun is shown in the figure) for spraying a coating material onto an object to be coated, and a coating color type is changed. It has a color change valve unit 2 for switching the paint every time and supplying it to the coating machine 1. The coating machine 1 and the color change valve unit 2 are connected by a paint hose 3. The color change valve unit 2 has a paint hose 3
Manifold 21 to which is connected and a plurality of switching valves 2
2, each switching valve 22 is supplied with each paint supplied from the paint tank, and the air and the cleaning solvent used during the color change cleaning.
In the figure, six switching valves 22a to 22d are shown as switching valves to which paint is supplied, one switching valve 22e is shown as a switching valve to which air is supplied, and a switching valve to which cleaning solvent is supplied is shown. One switching valve 22f is shown. It should be noted that one switching valve 22e, 22f to which air and a cleaning solvent are supplied is sufficient, but the switching valves 22a to 22d to which paint is supplied are
There are as many types of paint colors as there are.

Switching valve 22 of color change valve 2
In the case of mass-produced colors, the paint pipes respectively connected to a to 22d may be laid from the paint preparation chamber, but the paint supply device of the present embodiment is a paint circulation system using a pig for the switching valve 22a. The present invention will be described with reference to an example in which Therefore, the other switching valves 22b, 22
A mass production color paint circulation system may be connected to c and 22d, or a paint circulation system using the pig according to the present invention may be connected.

A paint circulating system 4 (hereinafter, also referred to as paint circulating pipe 41) is provided to one switching valve 22a of the color change valve unit 2 via a paint pipe 6.

The coating material for coating the object to be coated is contained in the coating material tanks 42A and 42B of the respective coating color types A and B (not limited to two colors), and the cleaning solvent (coating material A is used). , B are both solvent-based paints.
When B is a water-based paint, the tank 43 stores cleaning water. ) Is contained in the paint tank 43, and the paint pipe 44 between this point and the paint circulation pipe 41 is used.
In addition, a four-way valve 45, a pump P for pumping the paint, and three-way valves 46 and 47 are provided. These constitute the outward path of the coating materials A and B and the cleaning solvent.

On the other hand, at the rear end of the paint circulating pipe 41, the return pipes 49 for the paints A and B and the cleaning solvent are connected via the four-way valve 48, and from there, the paints A and B and the cleaning solvent are returned. Is the respective paint tank 42A, 42B, 43
Will be returned to. A drain pipe 51 is connected to the paint circulation pipe 41 upstream of the four-way valve 48 via a three-way valve 50. These constitute a return path for the paints A and B and the cleaning solvent.

On the other hand, a paint pipe 41a is connected to the rear end side (downstream side) of the paint circulation pipe 41 via a three-way valve 52, and the tip of the paint pipe 41a is connected to the three-way valve 47 described above. . A pig station PS is provided in the middle of the paint pipe 41a. Pig Station PS
Means that the second pig PG2 can be fired from the station and the second pig PG2 returning to the station can be captured, and its specific structure is not particularly limited. Further, before and after the pig station PS, opening / closing valves 53 and 54 for allowing / not allowing the second pig PG2 to move in and out of the pig station PS are provided, and the pig station PS and the opening / closing valve 54 are provided.
Two pipes 55 and 56 for supplying a cleaning solvent to the pig station PS are connected to the downstream side of the. On-off valves 57 and 58 for turning on / off the supply of the cleaning solvent are provided in the respective pipes 55 and 56. Furthermore, in the pig station PS, the pipe 5
The drain pipe 59 for discarding the cleaning solvent supplied from 5, 56 is connected, and the drain pipe 59 is provided with an opening / closing valve 60. As a result, the second pig PG2 can be cleaned at the pig station PS.

The second pig PG in this embodiment
2 means, for example, when changing the coating color from A color to B color,
Immediately after the color and immediately before the cleaning solvent, the color A adhering to the inner wall of the paint circulation pipe 41 is scraped off,
Immediately after the cleaning solvent and immediately before the color B, the cleaning solvent adhering to the inner wall of the paint circulation pipe 41 is scraped off.
Therefore, as shown in FIGS. 3 to 7, the second pig PG
2 is fired from the pig station PS, and the on-off valve 54 →
It returns to the pig station PS via the route of the three-way valve 47 → three-way valve 52 → open / close valve 53. Therefore, the on-off valve 54, the three-way valve 47, the three-way valve 52 and the on-off valve 53 are the second
The pig PG2 of FIG.

Next, the structure between the paint circulation pipe 41 and the color change valve unit 2 will be described. Figure 2
As shown in FIG. 5, the paint pipe 6 connecting the paint circulation pipe 41 and the color change valve unit 2 includes a shutoff valve 61 and a first three-way valve in order from the paint circulation pipe 41 side (upstream side in the present invention). A valve 62 and a second three-way valve 63 are provided. Here, in order to collect more of the previous color paint remaining in the paint pipe 6 at the time of color change and to improve the cleanability of the paint pipe 6, the opening / closing valve 61 and the first three-way valve 62 are
As close to the paint circulation pipe 41 as possible,
It is desirable that the three-way valve 63 is located as close as possible to the switching valve 22a of the color change valve unit 2.

The first three-way valve 62 includes two switching valves 6
The cleaning solvent and the cleaning air (these are the cleaning fluid according to the present invention) are supplied through 4, 65 and the pipe 66. Further, extrusion air (extrusion fluid according to the present invention) is provided to the second three-way valve 63 via the switching valve 70 and the pipe 68.
Is supplied.

In particular, in the present embodiment, in order to clean the paint pipe 6 at the time of color change, the first pig PG1 is reciprocated in the paint pipe 6 separately from the second pig PG2.
Therefore, the first three-way valve 62 and the second three-way valve 63
Each have a function of firing, capturing and cleaning the first pig PG1, like the pig station PS of the paint circulating pipe 41 described above. That is, as shown in FIG. 2, the first pig PG1 has a size corresponding to the inner diameter of the paint pipe 6 and is symmetrically formed in the front-rear direction for reciprocating movement. 62 and the second three-way valve 63, each of which is fired toward the other three-way valve and is captured, and each three-way valve 62, 6
Washed in 3. The specific structure of the first pig PG1 is not particularly limited. Further, when the paint pipe 6 is washed, the first pig PG1 may move inside the pipe 6 on one side.

When the extruding air is supplied to the second three-way valve 63, the first pig PG1 is fired together with this air, and the first pig PG1 is placed between the air and the residual paint.
It is preferable that the interposition of the can prevent the extrusion air from passing through between the paints that are about to be pushed out, thereby improving the paint recovery rate. According to what the present inventor has confirmed, the paint recovery rate in the paint pipe 6 is about 40 to 50% when only the air for extrusion is used, whereas the first pig PG1 is interposed. In this case, the paint recovery rate in the paint pipe 6 was improved to about 90%.

Next, the operation will be described. 3 to 7 are diagrams showing the operation state of the entire paint supply device, and FIGS. 9 to 14 are diagrams showing the operation state of the paint pipe 6 during color change. In the following description, assuming that A color is first painted and then B color is painted, the operation of the entire paint circulation pipe 41 (FIGS. 3 to 7) and the operation of the paint pipe 6 (FIGS. 9 to 14) ) And. 3 to 7, the detailed structure of the paint pipe 6 is omitted.

First, in order to supply the color A to the coating machine 1, the pump P is operated to suck the paint A in the paint tank 42A from the paint pipe 44 and pressure-feed it to the paint circulation pipe 41 via the three-way valve 47. . The paint A is returned to the paint tank 42A via the three-way valves 52, 50 and the four-way valve 48. In this way, the paint A circulates in the paint circulation pipe 41. This state is shown in FIG. 3. Here, as shown in FIG. 9, the opening / closing valve 61 of the paint pipe 6 is opened so that the paint A flows from the paint circulation pipe 41 to the switching valve 22a of the color change valve unit 2. When the directions of the two three-way valves 63 and 53 are switched, the paint A circulating in the paint circulation pipe 41 is supplied to the coating machine 1 via the switching valve 22a of the color change valve unit 2 and the paint hose 3.
At this time, the first pig PG1 is captured and held by the second three-way valve 63, and the paint A passes by the side of the first pig PG1.

Next, the procedure for changing the color from the previous color A to the next color B will be described. First, as shown in FIGS. 3 and 10, the pump P is stopped while the paint A is circulating in the paint circulation pipe 41. As a result, the paint pressure in the paint circulation pipe 41 decreases, so that the open / close valve 61 and the first three-way valve 62 of the paint pipe 6 remain as they are.
The direction of the second three-way valve 63 is switched to the direction shown in FIG. Then, as shown in the figure, the switching valve 70 is opened to supply the extrusion air, but the first pig PG1 captured by the second three-way valve 63 by the supply pressure of the air at this time.
Is fired and moves in the paint pipe 6 toward the first three-way valve 62.

As shown in the figure, the paint pipe 6 is filled with the residual paint A on the left side of the figure, the first pig PG1 on the right side thereof, and the extrusion air AR on the right side thereof. The paint A remaining between the second three-way valve 63 and the first three-way valve 62 is pushed out to the paint circulation pipe 41 by the first pig PG1 and the extrusion air AR, and is collected.

Then, when the first pig PG1 arrives at the first three-way valve 62, it is captured and held there, but the extruding air AR from the rear is the first pig PG1.
After passing the side of the
Push back to 1. Here, the on-off valve 61 is closed so that the next cleaning solvent and cleaning air do not enter the paint circulation pipe 41.

In this way, the residual paint A is applied to the paint circulation pipe 4
When the residual paint A is extruded by the extruding air AR with the first pig PG1 interposed when extruding to the No. 1, it is possible to prevent the extruding air AR from passing through the residual paint, and most of the residual paint The paint A can be collected in the paint circulation pipe 41.

As shown in FIG. 11, when the paint A remaining between the second three-way valve 63 and the paint circulating pipe 41 is pushed out to the paint circulating pipe 41, the first three-way valve 62 and the second
The direction of the three-way valve 63 is switched as shown in FIG. 12, the switching valve 64 is opened, and the cleaning solvent is supplied from the pipe 66.
Due to the supply pressure of the solvent at this time, the first pig PG1 captured by the first three-way valve 62 is fired and moves in the paint pipe 6 toward the second three-way valve 63. Then, when the first pig PG1 arrives at the second three-way valve 63, the first pig PG1 is trapped there and held in place, but the cleaning solvent from the back is first
Pass the side of Pig PG1. As a result, the inside of the pipe between the first three-way valve 62 and the switching valve 22a of the color change valve unit 2 is cleaned, and the cleaning liquid is supplied from the dump valve provided to the switching valve 22a.
Or it is discarded from the coating machine 1. Also, when the cleaning solvent passes through the second three-way valve 63, the second three-way valve 63
The first pig PG1 that has been captured by is also washed at the same time. In addition, the first pig PG1 is the first three-way valve 6
There is also a method of supplying the cleaning solvent while being captured and held by 2 to clean the portion, but in this case, the first pig PG1 moves from the first three-way valve 62 to the second three-way valve 63. The timing of movement is when the B color to be painted next is supplied from the paint circulation pipe 41 to the paint pipe 6 (FIG. 8).
reference). That is, the first three-way valve 6
Fire the first pig PG1 captured by the second
To be captured by the three-way valve 63.

Then, the switching valve 64 is closed and the switching valve 65 is opened to supply the cleaning air from the pipe 66 (see FIG. 13). As a result, the cleaning solvent supplied between the first three-way valve 62 and the switching valve 22a of the color change valve unit 2 is pushed out and discarded from the dump valve provided in the switching valve 22a or from the coating machine 1. To be done. By repeating the supply of the cleaning solvent and the cleaning air once or plural times, the paint pipe 6 between the first three-way valve 62 and the switching valve 22a of the color change valve unit 2 is cleaned, and the color changing operation is performed. Complete (Figure 1
4).

Incidentally, a general color changing operation from the color change valve unit 2 to the coating machine 1 will be additionally described. For example, if the paint A supplied from the switching valve 22a of the color change valve unit 2 is currently applied and the next paint is the paint B supplied from the switching valve 22b, the above-mentioned paint piping is first described. After the cleaning of the paint A remaining in 6 is completed, the switching valve 2
After closing 2a, the switching valve 22e is opened to supply compressed air to the color change valve unit 2 and the subsequent parts.
As a result, the paint A remaining between the color change valve unit 2 and the coating machine 1 is pushed out from the coating machine.

Next, the switching valve 22e is closed and the switching valve 22f is opened to supply the cleaning solvent to the color change valve unit 2 and the subsequent components. As a result, the paint A attached to the inner wall of the paint passage between the color change valve unit 2 and the coating machine 1 can be washed.

Further, the switching valve 22f is closed to stop the supply of the cleaning solvent, and the switching valve 22e is restarted.
Open and supply compressed air to the color change valve 2 and later, and from the color change valve unit 2 to the coating machine 1
The cleaning solvent remaining until is pushed out from the coating machine 1. The above operation may be repeated for a plurality of cycles in order to further improve the cleaning property. However, when sufficient cleaning property can be obtained in one cycle, the switching valve 22e is closed and then the switching valve 22a is opened to open the next color. The paint B is supplied to the color change valve unit 2. However, such a color changing operation can be omitted if the washing solvent disposal path shown in FIG. 12 is a painting machine.

Returning to FIG. 4, the color changing operation of the paint circulating pipe 41 will be described. The pump P, which has been temporarily stopped to collect the residual paint A in the paint pipe 6, is restarted, and the opening / closing valve 54 is opened to shoot the second pig PG2 from the pig station PS to the paint circulation pipe 42. . In parallel with this, the four-way valve 45 is switched to stop the suction of the paint A,
Start aspirating cleaning solvent. This timing is the second
When the pig PG2 is discharged from the pig station PS and reaches the three-way valve 47, it is desirable that the cleaning solvent comes behind the second pig PG2. The four-way valve 4
The paint A remaining between the No. 5 and the three-way valve 46 is discarded from the drain pipe of the three-way valve.

As a result, as shown in FIG. 4, the paint A is filled in front of the second pig PG2, and the second pig PG2 is filled.
The mixed liquid of the paint A and the cleaning solvent is filled in the rear of 2, but the paint A adhering to the inner wall of the paint circulation pipe 41 is scraped off as the second pig PG2 advances. The cleaning solvent filled in the rear of the second pig PG2 shortens the cleaning time of the paint circulation pipe.

Incidentally, as shown in FIG. 4, the second pig P
G2 is returned to the pig station PS via the three-way valve 52, where the second pig PG2 to which the paint A has adhered is washed. At that time, the cleaning solvent is supplied from the pipes 55 and 56 and is discarded from the pipe 59.

Further, in the state shown in FIG. 4, the paint A filled in front of the second pig PG2 is not mixed with the cleaning solvent, so it is collected in the paint tank 42A.
Since the paint A filled immediately after the second pig PG2 contains the cleaning solvent, the paint A is discarded from the drain pipe 51 via the three-way valve 50, and the paint A filled thereafter is cleaned with a small mixing ratio. The solvent for use is returned to the tank 43.

In this way, the cleaning solvent circulates in the paint circulation pipe 41 to clean the inside of the pipe as shown in FIG. After the circulation of the cleaning solvent for a certain period of time, the opening / closing valve 54 is opened to eject the second pig PG2 from the pig station PS to the paint circulation pipe 42. In parallel with this, the four-way valve 45 is switched, the suction of the cleaning solvent is stopped, and the suction of the paint B is started. Regarding this timing as well, the second pig PG
It is desirable to have the paint B come behind the second pig PG2 when 2 is fired from the pig station PS and reaches the three-way valve 47. The cleaning solvent remaining between the four-way valve 45 and the three-way valve 46 is discarded from the drain pipe of the three-way valve.

As a result, as shown in FIG. 6, the cleaning solvent is filled in front of the second pig PG2, and the mixed solution of the cleaning solvent and the paint B is filled in the rear of the second pig PG2. However, as it goes away from the second pig PG2 rearward, only the paint B becomes liquid.

Then, as shown in FIG. 6, when the second pig PG2 reaches the three-way valve 52, the second pig PG2 is returned to the pig station PS and washed. At this time, the cleaning solvent filled in front of the second pig PG2 is stored in the tank 4
However, since the cleaning solvent is mixed in the paint B immediately after the second pig PG2, it is discarded from the three-way valve 50 for a certain period of time, and then the four-way valve 48 is switched and returned to the paint tank 42B. .

The above-described embodiments are described for facilitating the understanding of the present invention, and are not described for limiting the present invention. Therefore, each element disclosed in the above-described embodiment is intended to include all design changes and equivalents within the technical scope of the present invention.

In the embodiment shown in FIG. 1, the paint circulation system 4 is set to 1
However, the present invention is not limited to this, and two or more may be provided to cope with the production tact. Also,
The paint supply device of the present invention is not limited to topcoating, but can be applied to intermediate coating.

[Brief description of drawings]

FIG. 1 is an overall view showing an embodiment of a paint supply device of the present invention.

FIG. 2 is an enlarged view showing a portion II of FIG.

FIG. 3 is a diagram showing an operation of the paint supply device shown in FIG. 1 (at the time of A color coating).

FIG. 4 is a diagram showing an operation of the paint supply device shown in FIG. 1 (at the time of A color recovery / filling with a cleaning liquid).

5 is a diagram showing an operation of the paint supply device shown in FIG. 1 (at the time of filling a cleaning liquid).

FIG. 6 is a view showing an operation of the paint supply device shown in FIG. 1 (at the time of cleaning liquid recovery and B color filling).

FIG. 7 is a diagram showing an operation of the paint supply device shown in FIG. 1 (at the time of B color coating).

FIG. 8 is a diagram showing the operation of FIG. 2 when changing colors (when introducing the next color paint).

FIG. 9 is a diagram showing the operation of FIG. 2 during color change (during paint introduction and painting).

FIG. 10 is a diagram showing the operation of FIG. 2 at the time of color change (at the time of completion of coating).

FIG. 11 is a diagram showing the operation of FIG. 2 at the time of color change (when introducing the fluid for extrusion and the first pig).

FIG. 12 is a diagram showing the operation of FIG. 2 at the time of color change (at the time of introducing the cleaning liquid).

FIG. 13 is a diagram showing the operation of FIG. 2 when changing colors (when introducing cleaning air).

FIG. 14 is a diagram showing the operation of FIG. 2 during color change (when color change is completed).

[Explanation of symbols]

1 ... Painting machine 2 ... Color change valve unit 22a-22f ... Switching valve 4 ... Paint circulation system 41 ... Paint circulation piping 6 ... Paint piping 61 ... Open / close valve 62 ... First three-way valve (first pig drive means) 63 ... Second three-way valve (first pig drive means) PG1 ... the first pig PG2 ... the second pig

Claims (7)

[Claims] 1. A paint supply device in which a paint circulation pipe is connected to a switching valve of a color change valve unit provided on the upstream side of a coating machine, the paint pipe connecting the switching valve and the paint circulation pipe. In order from the upstream side, an on-off valve that turns on and off the passage of the paint supplied from the paint circulation pipe, a first direction switching valve to which the cleaning fluid is supplied, and a second to which the extrusion fluid is supplied.
And a first direction for movably firing and capturing the first pig in the paint pipe between at least the first direction switching valve and the second direction switching valve. A paint supply device having a pig drive means. 2. The first pig driving means includes a pig station provided in each of the first direction switching valve and the second direction switching valve and capable of firing and capturing the first pig. The paint supply device according to claim 1. 3. When the painting of the previous color is completed, an extruding fluid is supplied to the second directional control valve, and the first directional drive valve switches the second directional control valve to the first directional control valve. The first pig is moved toward the valve so that the previous color paint remaining in the paint pipe between the second direction switching valve and the paint circulation pipe is circulated through the first pig. The paint supply device according to claim 1 or 2, which is pushed out into a pipe. 4. The method according to claim 1, wherein the first direction switching valve is provided near the paint circulation pipe, and the second direction switching valve is provided near the switching valve. The paint supply device described. 5. The paint supply device according to claim 1, wherein a pump for pumping the paint is provided in the paint circulation pipe, and the pump is stopped at the time of color change. 6. The first opening and closing valve is opened at the time of painting,
The paint supply device according to any one of claims 1 to 5, wherein the direction switching valve and the second direction switching valve are switched to a position where the paint in the paint circulation pipe is passed to the switching valve. 7. The paint supply device according to claim 1, wherein a second pig is inserted in the paint circulation pipe.