JP3042298B2 - Thinner extrusion coating method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thinner extrusion coating method for performing a coating while extruding a final part of the coating with a thinner when changing the color of the coating.

[0002]

2. Description of the Related Art Japanese Patent Application Laid-Open No. 5-200355 discloses a coating apparatus in which a color change valve and a gate valve are provided behind a coating gun, and a cleaning thinner supply source and an air supply source are provided further behind the gate valve. ing. When the color of the paint is changed (for example, when the color is changed from the color A to the color B), the color change valve of the color change valve is closed and the final portion of the color A paint (between the color change valve and the paint gun) is closed. In order to make effective use of the part located in the hose, the final part may be subjected to a so-called thinner extrusion coating in which the coating is performed while the thinner is being sent and extruded. Then, after thinner and air are alternately sent to wash the path between the coating gun and the color change valve, the color change valve B is opened. In the conventional thinner extrusion coating, the above-mentioned Japanese Unexamined Patent Publication No.
As described in JP 2003355, the thinner valve and the gate valve are simultaneously opened while the color change valve is closed.

[0003]

However, in the method of opening the thinner valve and the gate valve at the same time that the color change valve is closed, the amount of paint discharged from the coating gun is reduced in switching from normal coating to thinner extrusion coating. It temporarily decreased, and in some cases, a state where painting was temporarily impossible occurred, and there was a practical problem. SUMMARY OF THE INVENTION It is an object of the present invention to provide a thinner extrusion coating method capable of suppressing or eliminating a change (temporary decrease) in a paint discharge amount from a coating gun when switching from normal coating to thinner extrusion coating. .

[0004]

In order to achieve the above object, a thinner extrusion coating method of the present invention comprises the following method. A thinner extrusion coating method in which the final part of the paint is extruded with a thinner, wherein the thinner valve is opened before the gate valve is opened, and then the gate valve is opened simultaneously with or before closing the color change valve. Method.

[0005]

According to the thinner extrusion coating method of the present invention,
Since the thinner valve is opened before the gate valve is opened, the air in the hose between the gate valve and the thinner valve is compressed by the thinner before the gate valve is opened. Then, at the same time or before closing the color change valve, the gate valve is opened, so when the color change valve is closed, at the same time or before that, the above-mentioned compressed air pressure is applied to the final part of the paint, and the paint Is pushed out of the coating gun with little or no reduction in flow rate and thinner extrusion coating is performed. Thus, a temporary decrease in the paint discharge amount at the time of switching from the normal coating to the thinner extrusion coating is suppressed or eliminated.

[0006]

1 to 3 show a thinner extrusion coating method according to an embodiment of the present invention. As shown in FIG.
A color change valve 3 is connected upstream of the coating gun 1 via a discharge amount regulator 2 by a hose or a pipe. A gate valve 4 is provided at the rear end of the color change valve 3. The thinner valve 5 and the air valve 6 are connected to the upstream side of the gate valve 4 via a hose 7 or a pipe. The color change valve 3 is composed of a manifold of a plurality of valves, and a paint circulation circuit independent of each other is connected to each of the plurality of valves.
In these paint circulation circuits, paints of different colors are circulated.

Using this apparatus, a coating method is performed as shown in FIG. During normal painting, gate valve 4
Is closed, the paint passes through the discharge rate regulator 2 from the color change valve 3 and reaches the painting gun 1 where painting is performed. When the color is changed, the inside of the hose is washed, so that the color change valve 3 is closed, the gate valve 4 is opened, and the air valve 6 and the thinner valve 5 are alternately opened to perform washing. In the present invention, when the paint in the hose from the color change valve 3 to the coating gun 1 is pushed by a thinner to perform the thinner extrusion coating before the inside of the hose is washed at the time of the color change, the following method is performed in the present invention.

When shifting from the normal coating to the thinner extrusion coating, as shown in FIG. 2, the thinner valve 5 is opened before the gate valve 4 is opened. Open the thinner valve 5 1 to 5 seconds before opening the gate valve 4. here,
The reason why the time is set to 1 second or longer is that if the time is shorter than 1 second, the air in the hose is not yet compressed to a sufficient pressure by the thinner. This is because the pressure of the air is sufficiently increased, so that it is not necessary to waste more time. If the time can be wasted, the time may be longer than 5 seconds. afterwards,
At the same time as or before closing the color change valve 3, the gate valve 4 is opened. However, gate valve 4
It is preferable that the color change valve 3 be closed before the color change valve 3 is opened and the thinner reaches the color change valve 3.

The operation of the thinner extrusion coating method of the present invention is as follows. FIG. 3 shows the paint 8 in the hose when shifting from the normal coating to the thinner extrusion coating.
And the movement of the air 9 and the thinner 10 are schematically shown. The time in FIG. 2 corresponds to the time in FIG. At the time of the normal coating (at the time), the paint is supplied through the color change valve 3 and the gate valve 4 and the thinner valve 5 are closed, so that no pressure is applied to the air 9. Next, by opening the thinner valve 5 1 to 5 seconds before the gate valve 4 is opened to start thinner extrusion coating, the air 9 of the hose 7 is compressed by the thinner 10 to become compressed air (FIG. 3). Time state). Then, at the time of thinner extrusion coating, by closing the color change valve 3 and opening the gate valve 4 simultaneously or slightly earlier,
Before the flow rate of the paint 8 decreases, the compressed air 9 expands at the same time, so that the flow rate of the paint 8 is kept constant (at the time of FIG. 3). After that, it goes without saying that the discharge amount during the thinner extrusion coating is kept constant by the thinner extrusion pressure and the discharge amount regulator 2. In this way, a temporary decrease in the discharge amount of the paint at the time of transition from normal painting to thinner extrusion painting is suppressed or prevented.

Further, since the gate valve 4 is opened almost at the same time when the color change valve 3 is closed, there is no fear that the thinner enters the paint supply source side from the color change valve 3.

[0011]

According to the present invention, by opening the thinner valve before opening the gate valve, the air in the hose can be compressed by the thinner, and at the same time as or slightly before closing the color change valve. By opening the gate valve, it is possible to prevent the flow rate of the paint from decreasing due to the expansion of the compressed air, and to suppress the decrease in the paint discharge amount that has conventionally occurred when switching from normal painting to thinner extrusion painting. Or can be eliminated.

[Brief description of the drawings]

FIG. 1 is a schematic system diagram of an apparatus used for a thinner extrusion coating method according to an embodiment of the present invention.

FIG. 2 is an opening / closing timing chart of respective valves at the time of washing, painting, thinner extrusion painting, and transition thereof.

FIG. 3 is a schematic diagram showing positions and volumes of paint, air, and thinner in a hose before a thinner valve is opened, when the thinner valve is opened, and when a gate valve is opened.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Painting gun 2 Discharge rate regulator 3 Color change valve 4 Gate valve 5 Thinner valve 6 Air valve 7 Hose 8 Paint 9 Air 10 Thinner

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-64-80461 (JP, A) JP-A-6-79224 (JP, A) JP-A-4-326958 (JP, A) Jpn. 24764 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) B05D 1/00-7/26 B05B 12/14

Claims (1)

(57) [Claims] 1. A thinner extrusion coating method for extruding a final portion of a paint with a thinner, wherein the thinner valve is opened before the gate valve is opened, and then the gate valve is opened simultaneously with or before closing the color change valve. And thinner extrusion coating method.