JPH04200663A - Electrostatic coating device for electrically conductive coating - Google Patents

Abstract

PURPOSE:To reduce the color changing time when multicolor coating is performed with an electrically conductive coating by freely detachably connecting each coating feed pipe to each color changing valve system and connecting the coating discharge port of each pump to each switching valve capable of connecting the discharge port alternately to an outlet passage on the electrostatic coating machine side and to an outlet passage on the waste liq. tank side. CONSTITUTION:When the coating by a pump 2A is finished and the impression of a high voltage on an electrostatic coating machine 1 is stopped, a male coupler 32 provided to the pipeline 29 from a low-pressure cleaning soln. source 28 is engaged with the female coupler 33 of a low-pressure cleaning soln. feed valve 20 by an air cylinder 30. A low-pressure cleaning air feed valve 19 and a low-pressure cleaning soln. feed valve 20 are alternately opened and closed to clean off the coating remaining from an outlet passage 15 provided to a switching valve 18A to the coating machine 1 with the low-pressure cleaning air and cleaning soln. from the coating machine 1. The cleaning air feed valve CVA of a color changing valve system 9A and a cleaning soln. feed valve CVW are alternately opened and closed, and the coating remaining covering from the system 9A to the pump 2A and switching valve 18A is cleaned off by the high-pressure cleaning air and cleaning soln. and discharged into a waste liq. tank 16.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an electrostatic coating device for coating conductive paints such as water-based paints, slurry paints, and metallic paints using an electrostatic paint machine to which a high voltage is applied. .

[Conventional technology]

When painting conductive paint such as water-based paint with an electrostatic paint applicator to which high voltage is applied, insulate the paint supply system of the paint applicator to prevent leakage of the high voltage applied to the electrostatic paint applicator. Because it is necessary to take countermeasures (Japanese Patent Application Laid-open No. 114-1983
(No. 366, Publication No. 56-141869), in a multi-color electrostatic coating device for automobile painting that changes paint colors from dozens of colors, there is a separate paint supply pipe for each color paint. There is the trouble of having to insulate the paint tank, etc.

For this reason, electrostatic painting using insulating resin paints, which consumes large amounts of harmful organic solvents, is still the mainstream in automotive painting, and the use of non-polluting water-based paints has been postponed.

However, in recent years, as the global environmental conservation movement has increased, there have been calls for restrictions on the use of organic solvents that produce pollutants such as hydrocarbons in the coating industry.

[Problem to be solved by the invention]

Therefore, in order to recommend painting with water-based paints, the present invention eliminates the need to take troublesome insulation measures for paint supply systems such as paint supply piping and paint tanks even when electrostatic painting is performed using conductive paints such as water-based paints. The main technical challenge is to make it unnecessary, and also to shorten the color change time when performing multi-color painting with conductive paint.

[Means for Solving the Problems] In order to solve these problems, the present invention provides an electrostatic coating device for electroconductive paint that uses an electrostatic coating machine to which a high voltage is applied. A plurality of pumps each have an inlet and a paint outlet through which a required amount of conductive paint introduced from the paint inlet is forced out at a predetermined flow rate depending on the paint output amount of the electrostatic coating machine. The paint supply pipes are installed in a completely insulated state, and are connected to the paint inlet of each pump in such a way that each paint supply pipe is connected to each color change valve device, each of which has a cleaning air supply valve and a cleaning liquid supply valve. At the same time, the paint discharge port of each pump is connected to each switching valve that switches and connects the paint discharge port to an outflow path on the electrostatic atomizer side and an outflow path on the drainage tank side, and Each drainage pipe connected to the drainage tank is configured to be detachably connected to the outflow path.

[Effect]

According to the present invention, while high voltage is not applied to the electrostatic coating machine, a paint supply pipe is connected to the paint inlet of each pump, and conductive paint is supplied into each pump through the paint supply pipe. Introduce.

When one pump is filled with a required amount of conductive paint necessary for painting, the paint supply pipe is removed from the paint inlet of each pump.

In addition, the drain pipe is also separated from the outflow path on the drain tank side of each switching valve to which the paint discharge port of each pump is connected.

In this state, a predetermined high voltage is applied to the electrostatic coating machine, and the paint discharge port of the pump filled with the required amount of conductive paint is connected to the outflow path on the electrostatic coating machine side using a switching valve. Conductive paint is forced out at a predetermined flow rate from the paint discharge port and is supplied to the static 1i paint sprayer.

At this time, each paint supply pipe is disconnected from the paint inlet of each pump, and each drain pipe is also disconnected from the drain tank side outlet of each switching valve to which the paint discharge port of each pump is connected. Since it is isolated from the electrostatic coating machine, the high voltage applied to the coating machine will not leak through each pump to the paint supply system or drainage system of the conductive paint.

Therefore, there is no need to take troublesome insulation measures for the entire paint supply system and liquid drainage system.

In addition, when one pump finishes painting, the electrostatic atomizer can be cleaned and the next painting can be started immediately with another pump. The pump can be cleaned and filled with paint in advance.

Therefore, the interval between the end of painting and the start of the next painting can be shortened, and in the case of a multicolor electrostatic coating apparatus, the time required to change paint colors can be shortened.

[Example] Hereinafter, an example of the present invention will be specifically described based on the drawings.

FIG. 1 is a flow sheet diagram showing an example of an electrostatic coating apparatus according to the present invention, and FIG. 2 is a time chart diagram showing its operation.

In this example, royal pumps 2A, 2B, and 2C, which alternately supply conductive paint to an electrostatic coating machine l to which a high voltage of 80 to 120 KVO is applied, are installed in an electrically insulated state. .

Each of the pumps 2A, 2B, and 2C has a paint inlet 3, and a required amount of conductive paint introduced from the paint inlet 3 into the cylinder 4 at a predetermined flow rate according to the paint discharge amount of the electrostatic paint sprayer. It has a paint discharge port 5 from which the paint is forced out.

The conductive paint introduced into the cylinder 4 is forced out from the paint outlet 5 by a piston 8 attached to the tip of an insulated shaft 7 that is reciprocated by a drive device 6 such as a motor or cylinder. .

Each paint supply pipe 10 connected to each color change valve device 9A, 9B, 9C is detachably connected to the paint inlet 3 of each pump 2A, 2B, 2C.

That is, each paint inlet 3 is provided with a female coupler 11, each paint supply pipe 10 is provided with a female coupler 2, and the male coupler 12 is connected to the air cylinder 1.
Each paint supply pipe 10 is fixed to the piston rod 14 of No. 3 and removably engaged with the female coupler 11 by expansion and contraction of the piston rod 14, thereby connecting each paint supply pipe 10 to the paint inlet 3 of each pump 2A to 2C. are detachably connected.

Note that the female coupler 11 and the female coupler 12 have a check valve structure that opens when they are fitted together.

In addition, each color change valve device 9A to 9C includes a plurality of color change valves C■ that supply conductive paint of each color in the same color scheme.
1 to C3, a cleaning air supply valve CVA and a cleaning liquid supply valve CVo that supply high-pressure cleaning air and high-pressure cleaning liquid.

Next, the paint discharge ports 5 of each of the pumps 2A, 2B, and 2C are connected to respective switching valves that switch and connect the paint discharge ports 5 to the outflow path 15 of one electrostatic coating machine and the outflow path 17 of 16 drainage tanks. 1
8A, 18B, and 18C, respectively.

In addition, the outflow path 15 of one example of the electrostatic coating machine is connected to each switching valve 1.
A low pressure cleaning air supply valve 9 and a low pressure cleaning liquid supply valve 20 are attached to the manifold to which 8A to 18C are attached.

Furthermore, a female coupler 21 is provided in the outflow path 17 of the 16 drainage tanks of each of the switching valves 18A to 18C, and a conical coupler 23 is provided in each drainage pipe 22 connected to the drainage tank 16. The eight-person coupler 23 is fixed to the piston rod 25 of the air cylinder 24 and removably fitted to the female coupler 21 by the expansion and contraction of the piston rod 25, so that each switching valve 18
The outflow paths 17 of the 16 drainage tanks A to 18C are detachably connected to each drainage pipe 22.

Note that the low pressure cleaning air supply valve 19 is connected to the insulating piping 2.
6, it is directly connected to a low pressure air supply source 27.

Further, the low-pressure cleaning liquid supply valve 20 is removably fitted with a female coupler 32 that is provided at the end FA of a pipe 29 that supplies cleaning liquid from the low-pressure cleaning liquid supply source 28 and is moved forward and backward by the piston rod 3I of the air cylinder 30. female coupler 3
3 is provided so that a cleaning liquid pipe 29 is detachably connected thereto.

The above is the configuration of the electrostatic coating apparatus shown in FIG. 1, and the operation thereof will be explained next.

When electrostatic coating is performed by sequentially and alternately supplying conductive paint of a desired color from each pump 2A to 2C to the electrostatic coating machine 1, for example, when the coating by the pump 2A is finished, the electrostatic coating machine 1 When the application of high voltage to the low-pressure cleaning liquid supply source 2 is stopped, the air cylinder 30 connects the female coupler 32 installed in the piping 29 of the low-pressure cleaning liquid supply source 20 to the female coupler 32 of the low-pressure cleaning liquid supply valve 20 from the state shown in FIG. The coupler 33 is fitted, and the low-pressure cleaning air supply valve 19 and the low-pressure cleaning liquid supply valve 20 are opened and closed alternately to remove the remaining paint from the outlet passage 15 provided with the switching valve 18A of the pump 2A to the static paint sprayer 1 under low pressure. The electrostatic coating machine 1 is cleaned and removed using cleaning air and low-pressure cleaning liquid.

At the same time, the female coupler 12 installed at the tip of the paint supply pipe 10 connected to the color change valve device 9A is connected to the female coupler 11 installed at the paint inlet 3 of the pump 2A that has finished painting. The drain connected to the drain tank 16 is connected to the female coupler 21 provided in the outlet passage 17 on the drain tank 16 side of the switching valve 18A connected to the paint discharge port 5 of the pump 2A. The female coupler 23 provided at the tip of the liquid pipe 22 is fitted with the air cylinder 24 to alternately open and close the cleaning air supply valve CVA and the cleaning liquid supply valve CV of the color change valve device 9A. The remaining paint is removed by high-pressure cleaning air and high-pressure cleaning liquid from the device 9A to the pump 2A and the switching valve 18A, and the remaining paint is discharged to the drain tank 16.

Next, when the cleaning is completed, the paint supply pipe 10 is disconnected from the paint inlet 3 of the pump 2A, and the drain pipe 2 is disconnected from the outlet passage 17 on the drain tank 16 side of the switching valve 18A.
2, and also disconnect the pipe 29 that supplies low-pressure cleaning liquid from the low-pressure cleaning liquid supply valve 20, and then connect the first
Return to the state shown in the figure.

Then, apply high voltage again to the electrostatic coating machine I, and pump 2
Open the switching valve 18C to which the paint discharge port 5 of C is connected, connect the paint discharge port 5 to the outflow path 15 of an example of an electrostatic atomizer, and use the conductive material prefilled in the cylinder 4 of the pump 2C. The paint is forced out from the paint discharge port 5 by the piston 8 and supplied in a fixed amount to the electrostatic coating machine 1, and the next coating is started.

In this way, there is no risk that the high voltage applied to the electrostatic atomizer 1 will leak to each paint supply pipe 0 or drain pipe 22 via each pump 2A to 2C, so each color change valve device Many color change valves C■1~ provided in 9A~9C
There is no need to insulate the entire paint supply system that supplies each color of conductive paint to the CV3.

Furthermore, when the painting by the pump 2C is finished, the application of high voltage to the electrostatic coating machine 1 is stopped, and electrostatic painting is started on the switching valve 18C connected to the paint discharge port 5 of the pump 2C according to the same procedure as above. The remaining paint is cleaned from the outlet passage 15 of the machine 1 to the electrostatic coating machine 1 using a low-pressure cleaning air supply valve 19.
At the same time, the remaining paint is removed from the color change valve device 9C through the pump 2C and the switching valve 18C by the cleaning air supplied to the color change valve device 9C. Cleaning is performed using high-pressure cleaning air and high-pressure cleaning liquid that are alternately supplied from valve CVA and cleaning liquid supply valve C0.

Also, while this cleaning is being performed, conductive paint of the desired color selected by the color change valves CV, ~Cv3 provided in the color change valve device 9A is applied to the two pumps that have already been cleaned. Fill.

As a result, the pump 2A is ready to start painting at any time when the cleaning of the pump 2C is finished, so wait for the pump 2C that has finished cleaning to be filled with paint and use that pump 2C next time. Compared to the case of starting another painting, the interval from the end of painting to the restart of painting is shortened by the amount of time required to fill the paint.

In addition, if the cylinders 4 of the pumps 2A to 2C have large capacities and take time to clean inside, the cleaning process and the paint filling process for each pump 2A to 2C can be repeated for each pump, as shown in Figure 2. If you use three opportunities to complete the process, once when the paint is finished and when the other two pumps have finished painting, the interval between the end of painting and the start of the next painting will be longer. You can get away with it.

In other words, after the painting by pump 2A is finished and the electrostatic coating machine 1
When the application of high voltage to is stopped, the electrostatic coating machine 1 is being cleaned with low-pressure cleaning air and low-pressure cleaning liquid alternately supplied from the low-pressure cleaning air supply valve 19 and the low-pressure cleaning liquid supply valve 20. Then, the inside of the pump 2A is cleaned with high-pressure cleaning air and high-pressure cleaning liquid supplied from the cleaning air supply valve CvA and the cleaning liquid supply valve CVo of the color change valve device 9A,
When the cleaning of the electrostatic coating device 11 is completed, the cleaning is interrupted even if the cleaning inside the pump 2A is not completed.

Then, when the next pump 2C finishes painting and the application of high voltage to the sprayer 1 is stopped, at this time as well, the static 1
Only while the sprayer 1 is being cleaned, the inside of the pump 2A is cleaned again with high-pressure cleaning air and high-pressure cleaning liquid supplied from the cleaning air supply valve C■ of the color change valve device 9A and the cleaning liquid supply valve CV1. and finish the cleaning.

Then, when the next pump 2B completes painting, the application of high voltage to the electrostatic atomizer 1 is stopped, and cleaning of the electrostatic atomizer 1 starts, until the cleaning is finished, , the conductive paint of the desired color selected by the color change valves Cv1 to CV3 of the color change valve device 9A is filled into the pump 2A after cleaning.

In this way, the color change time in multi-color painting can be shortened and painting productivity can be increased.

〔Effect of the invention〕

As described above, according to the present invention, even when electrostatic painting is performed using conductive paint such as water-based paint, there is no need to take troublesome insulation measures for the entire paint supply system for the conductive paint. Even a multi-color electrostatic coating device having a paint supply system for ten colors has the very valuable effect of being able to perform electrostatic coating using non-polluting water-based paint without increasing equipment costs.

In addition, it has the excellent effect of shortening the interval between finishing one coat and starting the next coat, and reducing the time required to change colors in multi-color coatings. It is useful in that it can promote the transition from electrostatic coating using a water-based resin paint to electrostatic coating using a water-based paint.

[Brief explanation of the drawing]

FIG. 1 is a flow sheet diagram showing an example of a static 1i coating apparatus according to the present invention, and FIG. 2 is a time chart diagram showing its operation. Explanation of symbols 1--Electrostatic coating machine, 2A, 2B, 2C-pump, 3.
-Paint inlet, 5--Paint outlet, 9A, 9B, 9C
-Color change valve device, CVA-cleaning air supply valve, CV w'---cleaning liquid supply hub, 10-paint supply piping, 11-female coupler, 12--female coupler,
13-air cylinder, 15-outflow path on the electrostatic coating machine side, I6-drainage tank, 17-outflow path on the drainage tank side,
18A, 18B, 18C, ---All replacement hull, 21' female coupler, 22-drainage piping, 23-female coupler, 2
4 Air cylinder. Patent applicant: Trinity Industries Co., Ltd.-2

Claims (1)

[Claims] In an electrostatic coating device for conductive paint that coats conductive paint with an electrostatic coating machine (1) to which a high voltage is applied, there is a paint inlet (3) and the required amount introduced from the paint inlet (3). A plurality of pumps (2A), (2B), (2C) each have a paint discharge port (5) through which a quantity of conductive paint is forced out at a predetermined flow rate depending on the paint discharge rate of the electrostatic coating machine (1). ) are installed in an electrically insulated state, and each pump (2A), (2B)
, (2C), a cleaning air supply valve (CV_A) and a cleaning liquid supply valve (CV_
Each color change valve device (9A), (9B), equipped with W)
Each paint supply pipe (10) connected to (9C) is removably connected, and each pump (2A), (2B
), (2C), the paint discharge port (5) is connected to the paint discharge port (
5) to each switching valve (18A), (18B), (18C) which is connected to the outflow path (15) on the electrostatic sprayer (1) side and the outflow path (17) on the drainage tank (16) side. connected,
With respect to the outflow path (17) on the side of the drain tank (16),
An electrostatic coating device for conductive paint, characterized in that drain pipes (22) connected to a drain tank (16) are detachably connected.