JPS5990660A - Electrostatic painting method - Google Patents

Abstract

PURPOSE:To improve the efficiency of an operation by washing the previous color between one color change valve and a sprayer at a high speed then performing painting of the next color, and washing the previous color remaining in the paint supply passage between a paint tank and the color change valve during painting. CONSTITUTION:A sprayer 1, color change valves 6, 7 which control a paint and a washing fluid, paint pipes 4, 5, and paint supply passage 14, 25 connecting the color change valve and paint tanks 17, 28 are provided. The washing fluid is supplied to the color change valve used for supplying the paint of the previous color between the valves 6, 7 upon ending of the painting of the previous color to wash the one color change valve, the one paint pipe and the sprayer. The paint of the next color is supplied from the other paint supply passage, via the other color change valve, and the other paint pipe, and is sprayed from the sprayer toward a substrate after the end of the above-mentioned washing. The previous color remaining between the one paint supply pipe and the one color change valve after the end of the washing between the above-described one color change valve and the sprayer is washed and after the end of such washing, the next but one color is circulated to prepare the next but one color.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrostatic coating system in which two or more colors of paint can be sequentially changed and sprayed using one sprayer.

Conventionally, large electrostatic coating equipment is equipped with a color change valve device, which has a thinner valve and an air valve on the most upstream side of the manifold, and colors A and B toward the downstream side. ,...N
The structure is such that paint valves for different colors are provided, and each of the paint valves is connected to a paint tank via a zerky ration vibrator, a paint bonder, etc., and an electrostatic sprayer is connected to the tip of the manifold via a paint pipe. was. Then, the paint is constantly circulated between each paint valve and the paint tank, and after the previous color is painted, sinker and air are alternately supplied from the thinner valve and the air valve to control the manifold, paint pipe, and spray machine for example 30 minutes. The structure was such that high-speed cleaning was carried out in a short period of about seconds, and after this cleaning was completed, the paint valve for the next color was opened to begin painting.

However, the large electrostatic coating equipment described above not only requires a large color change valve device, but also requires N paint tanks, paint pumps, and N circulation pipes.
It has the disadvantage that it is very expensive. Therefore, there is a problem in that it is unsuitable for anything other than large-scale applications such as those in which car bodies transported on a conveyor are sequentially painted in an automobile factory or the like.

On the other hand, in a simple electrostatic painting device, one end of a paint pipe is connected to a paint tank, an electrostatic sprayer is installed at the other end of the paint pipe, and a paint bonder is installed in the middle of the painting/vibe. What is the configuration? In order to change colors and spray two or more colors of paint sequentially using such a simple electrostatic painting device, connect a sinker tank to one end of the paint pipe after painting the previous color, and use the paint pump to pump the sinker into the paint. Clean the paint pump, paint pipe, electrostatic sprayer, etc. with l- supplied from the vibrator to the electrostatic sprayer, then connect the paint tank of the next color to one end of the paint pipe, and use the next color to clean the sinker in the paint pipe. After purging, the next color was applied.

However, although the above-mentioned simple electrostatic coating equipment is small and can be manufactured at low cost, it requires about 10 minutes of cleaning time and is difficult to use when painting with frequent color changes. had the disadvantage of poor workability.

The present invention focuses on the advantages of a simple electrostatic coating device in that the device is small and can be manufactured at low cost. As with large electrostatic coating equipment, even if the paint is at 30, the next color is sprayed from the electrostatic sprayer, and the previous color remaining in the paint supply passage between the color change valve and the paint tank is cleaned. The present invention provides an electrostatic coating method in which

In order to achieve the above object, the present invention includes one sprayer that sprays paint while applying a high voltage, and a first sprayer that controls the paint and cleaning fluid to be supplied to the sprayer.
A second color change valve, first and second paint pipes connecting the sprayer and each color change valve, and a connection between the first and second color change valves and the paint tank. After the painting of the previous color is completed, one of the first and second color change valves used for supplying the paint of the previous color is cleaned. After cleaning, the primary color paint from the other paint supply passage is supplied to the other color change valve and the other paint vibrator. The paint is sprayed from the sprayer towards the object to be coated through the sprayer, and remains between the one paint supply passage and the one color change valve after the above-mentioned cleaning between the one color change valve and the sprayer is completed. An electrostatic coating method characterized in that the previous color is washed, and after this washing is completed, the colors are circulated one after another between the one paint supply passage and the one color change valve to prepare for spraying of successive colors. It is in.

With the above-mentioned configuration, the previous color between one color change valve and the sprayer is washed at high speed, and when the sprayer becomes clean, the next color is immediately supplied to the sprayer from the other color change valve. The next color can then be applied, reducing cleaning time. Further, while the next color is being sprayed, the previous color remaining in the paint supply passage between the paint tank and the color change valve can be cleaned, making the work more efficient. Furthermore, even when applying high voltage and spraying the next color, one of the paint vibrators will be clean after washing the previous color, so the color changing valve or paint on one side will be The supply passage, paint tank, etc. can be grounded and maintained at earth potential, and even when using conductive paint, color changing work can be performed safely.

The present invention will be described below along with embodiments shown in the drawings.

In FIG. 1 and FIG. 2, 1 indicates a sprayer, and the sprayer 1 includes a rotary atomizing head type sprayer using centrifugal atomization, an air atomizing type sprayer using air atomization, etc. used. The sprayer 1 is connected to a high-voltage generator 3 via a high-voltage cable 2, and the sprayer 1 is attached to a reciprocator I (as required) so as to reciprocate and direct the sprayer 1 toward the object to be coated. It is configured to be able to spray paint.

4.5 indicates first and second paint pipes, one end of each of the paint vibrators 4 and 5 is connected to the sprayer 1, and the other ends are connected to the first and second color change pipes, respectively, which are kept insulated. It is connected to valves 6 and 7. Here, the length of each paint pipe 4, 5 is relatively short, about 40 to 5 cm, and the material is highly insulating and can easily repel paint, sinker, etc. Water-repellent materials such as Teflon and polyethylene are used.

In addition, the first color change valve 6 described above also serves as a manifold 8, an air valve 9 fixed to the manifold 8, a thinner valve lO1 and a paint valve 11, and the air valve 9 is connected to an air source 12,
The sinker valve 10 is connected to the sinker source 13 and is also connected to the paint valve 1.
1 is connected to a first paint supply passage 14 made of a conductive material.

A pump 16 driven by a motor 15 is inserted into the supply side 14A of the paint supply passage 14, and the supply side 14A and return side 14B of the paint supply passage 14 are both inserted into the first paint tank 17. The paint tank 17 is placed on an insulating stand 18''.

On the other hand, the second color change valve 7 also has a manifold 19 and an air valve 20.
, a sinker valve 21, and a paint valve 22, the air valve 20 is connected to an air source 23, the sinker valve 21 is connected to a sinker source 24, and the paint valve 22 is connected to a second paint supply passage made of conductive forest material. 25 are connected. A pump 27 driven by a motor 26 is inserted into the supply side 25A of the paint supply passage 25, and the supply side 25A and return side 25B of the paint supply passage 25 are both connected to a second paint tank 28.
The paint tank 28 is placed on an insulating stand 29.

Furthermore, among the first and second color change valves 6 and 7, for example, the first
The 0 color changing valve 6 is constructed as shown in FIG. That is,
The manifold 8 has a passage 8A formed therein, and an air valve 9 and a sinker valve 10 are connected to the upstream side of the passage 8A.
A paint valve is connected to the downstream side thereof, and the passage 8A is further connected to the first paint pipe 4. Here, the air valve 9 is formed in its casing with a valve chamber 9A communicating with the passage 8A of the manifold 8 and the air source 12, and a partition chamber 9C in which a partition 9B such as a piston or a diaphragm is provided inside. A valve body 9E is provided in the valve chamber 9A and is seated on and off the valve seat 9D.The valve body 9E is connected to a partition wall 9B via a valve stem 9-.The valve body 9E is disposed on one side of the partition wall 9B. Always keep the valve seat 9
A spring 9G biasing toward the D side is stretched, and a drive air supply port 9H is formed on the other side. In addition, sinker valve 10
also has the same configuration as the air valve 9, with a valve chamber 10A1 and a partition wall 10.
B, partition chamber 10C1 valve seat 10D, valve body 10E, valve stem 10
Consists of F1 spring IOG and drive air supply port 10H. Further, the paint valve 11 has a valve chamber 11A in its casing that communicates with the passage 8A of the manifold 8, the supply side 14A and the return side 14B of the paint supply passage 14, and a partition wall provided with a partition wall 11B such as a piston and a diaphragm inside. A chamber 11C is formed, and valve seats 11D and 11F are formed in the valve chamber 11A.
A valve body 11F is provided which seats and leaves the valve body 11F, and the valve body 11F is connected to the partition wall 11B via the valve stem 11G.
A spring 111 (for constantly biasing the valve body 11F toward the valve seat 11D) is provided on one side, and a driving air supply port 1 is provided on the other side.
1J is formed. In the figure, 30.31 is the insulation stand 18
．． This is a sinker tank that stores a washing sinker placed near No. 29.

The present invention is constructed as described above, and its operation will now be explained with reference to the operation diagram of FIG. 3.

First, the paint tank 17 is the color A, and the first paint supply passage 14, the tenth color changing valve 6, the paint pipe 4, etc. are filled with the color A, and the paint tank 28 is the previous color, and the third color is filled with the paint tank 28. sushi)
Although the second paint supply passage 25 is filled with the previous color, it is assumed that the second paint pipe 5 has been washed and is clean.

Here, when the sprayer 1 is a rotary atomizing head type sprayer, to paint color A, the sprayer 1 is rotated at high speed as shown in Fig. 3 (a), (b), and (c), and the reciprocator is R is actuated to reciprocate the atomizer 1 and apply high voltage from the high voltage generator 3 to the rotating atomizing head.

Next, when air is supplied from the driving air supply port 11J of the paint valve 11, the partition wall 11B is displaced upward against the spring 11), and the valve body 11F is seated on the valve seat 11E. As a result, paint of color A can be supplied from the paint supply passage 14 to the sprayer 1 via the valve chamber 11A, the passage 8A of the manifold 8, and the paint pipe 4.

As a result, as shown in Fig. 3), color A is sprayed from the sprayer 1 toward the object to be coated, which flies along the electric lines of force between the nuclear sprayer 1 and the object to be coated by suction. . As a result, the color A is painted.

During this time, the operator removes the paint tank 28 of the previous color from the insulating stand 29, places the sinker tank 31 on it, drives the pump 27, and supplies the sinker to the paint supply passage 25.
From pump 27, paint valve 22 of color change valve 7, return side 25B
The previous color remaining in the paint supply passage 25, pump 27, and paint valve 22 is washed away. As a result, the previous color in the second paint supply passage 25 is cleaned as shown in FIG. 3(E). After this cleaning is completed, the insulation table 29
Remove the sinker tank 31, place the B color paint tank 28, and operate the pump 27 again to circulate B color between the second paint supply passage 25 and the paint valve 22 to prepare for the next color painting. I'll keep it.

On the other hand, when the sprayer 1 finishes spraying the paint of color A in FIG.

In this state, the color change valve 6 is operated as shown in FIG. When air is supplied from the drive air supply port 9H, the partition wall 9B is displaced upward against the spring 9G, and the valve body 9E is separated from the valve seat 9D. Aisle 8A
, are supplied to the sprayer 1 via the paint pipe 4, and the A color inside these is purged. Next, after closing the air valve 9,
Similarly to the above, air is supplied from the driving air supply port 10I of the thinner valve 1o to open the valve body 10E, and the sinker from the thinner source 13 is supplied to the manifold 8, the paint pipe 4, and the sprayer 1. Clean the inside. By repeating the supply of cleaning air and sinker multiple times as described above, the manifold 8, paint pipe 4, and sprayer 1 are thoroughly cleaned.

At this time, by using a water-repellent and insulating material as the paint pipe 4, the sinker, etc. inside the paint pipe 4 is repelled and becomes dry, so even if high voltage is applied to the sprayer 1, the color will not change. High voltage is not applied to replacement valve 6. Therefore, if a conductive material is used for the paint supply passage 14 and the pump 16 and the paint tank 17 are brought to earth potential by, for example, connecting the pump 16 and the paint tank 17 to earth with a grounding rod or an air cylinder, the color change valve 6
Since the paint tank 17 can also be set to earth potential, operations such as removing the paint tank 17 can be performed safely even if a conductive paint is used.

Furthermore, when cleaning the space between the color change valve 6 and the sprayer 1 mentioned above, the color change valve 6 is automatically operated according to a predetermined program to perform high-speed cleaning in a short time of about 30 seconds or less. This, coupled with the fact that the paint pipe 4 is short, can shorten the cleaning time.

After cleaning the sprayer 1 as described above, the third
As shown in the figure (f), the paint valve 22 of the second color change valve 7 is opened for a short time, and the B color from the paint supply passage 25 is transferred to the paint pipe 5.
It is supplied to the sprayer 1 via the. Using this button, preparations are made so that the object to be painted with B color can be immediately painted. On the other hand, as mentioned above, the paint pipe 5
By filling the interior with color B, the paint tank 28 is placed on the insulating stand 29 (in this case, the paint tank 28
(not grounded), even if conductive paint is used as color B, high voltage is applied to the sprayer 1 and at the same time the color change valve 7, paint supply passage 25, paint tank 28, etc. are connected via the paint in the paint pipe 5. A high voltage having the same potential as that of the sprayer 1 is applied to the sprayer 1, thereby preventing fires caused by spark generation.

Furthermore, when the next object to be coated arrives from the above-mentioned state, the reciprocating rotor R=i is operated again and a high voltage is applied to the sprayer 1, and the paint valve 22 is opened at 5 as shown in Fig. 3). Then spray the paint of color B from the sprayer 1 and start painting.

Meanwhile, the cleaning of the paint pipe 4 is completed 1. Since it is electrically insulated, remove the A color paint tank 17 from the insulating stand 18 as described above, place the sinker tank 30, and drive the pump 16 to connect the sinker to the paint supply passage 14 and the pump 16. , and the paint valve 11 to wash out the color A remaining inside these parts (see FIG. 3(G)). After this cleaning is completed, the sinker tank 3o is removed from the insulating stand 18, the C color paint tank 17 is placed thereon, and the pump 16 is operated again to circulate C color between the paint supply passage 14 and the paint valve 11.

By repeating the above-described operations, the first paint supply system consisting of the first paint supply passage 14, color change valve 6, and four paint pipe caps produces A color 5. C color.

A second paint supply system consisting of a second paint supply passage 25, a color change valve 7, a paint pipe 5, etc. supplies paint for colors B, D, F, etc.・The paint is supplied sequentially from one sprayer 1 to color A, color B, etc.
N color paint can be sprayed.

Since the electrostatic spraying method according to the present invention has been described in detail above, the cleaning time of the sprayer can be shortened with a simple configuration, and the preparation for painting the next color can be carried out using the painting process of the previous color. You can improve your work efficiency. Additionally, if you program the paint pipes and sprayers to automatically clean them, you can further increase work efficiency. Moreover, it has many advantages, such as being able to use either conductive paint or insulating paint as the paint.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram of an electrostatic coating apparatus used in the present invention, FIG. 2 is a sectional view of a color change valve, and FIG. 3 is an explanatory diagram of the operation of the system according to the present invention. 1... Sprayer, 3... High voltage generator, 4, 5...
1st and 2nd paint pipes, 6, 7... 1st and 2nd color change valves 8.19... manifolds, 9, 2o--air valves, 10.21... thinner valves, 11 , 22...Paint valve, 14.25...First and second paint supply passages, 16°27...Pump, 17, 28...Paint tank,
3o. 31... Thinker tank.

Claims (4)

[Claims] (1) one sprayer that sprays paint while applying a high voltage; first and second color change valves that control the paint and cleaning fluid to be supplied to the sprayer; first and second paint pipes connecting the sprayer and the color change valve;
first and second paint supply passages connecting the first and second color change valves and the paint tank; Cleaning fluid is supplied to one of the color change valves used to supply paint for the previous color to clean the color change valve, one paint pipe, and the sprayer, and after this cleaning is completed, the other paint supply passage is The paint of the next color is sprayed from the sprayer toward the object to be coated through the other color change valve and the other paint pipe, and after the above-mentioned cleaning between the one color change valve and the sprayer is completed, the The previous color remaining between one paint supply passage and one color change valve is cleaned, and after this cleaning is completed, the colors are circulated one after another between the one paint supply passage and one color change valve. An electrostatic coating method that is characterized by being prepared for color splashes. (2) After cleaning one color change valve, one paint pipe, and the sprayer used for the previous color, supply the next color from the other color change valve to the sprayer for a short time, and then supply the next color to the other paint pipe for the next color. The electrostatic coating method according to claim (1), wherein the electrostatic coating method is filled with color. (3) The electrostatic coating method according to claim (1), wherein water-repellent pipes are used for the first and second paint pipes. (4) The electrostatic coating method according to claim (1), wherein the first and 20th color change valves each include one air valve, one thinner valve, and one paint valve.