JPH04200664A - Electrostatic coating device for electrically conductive coating - Google Patents

Abstract

PURPOSE:To reduce the color changing time by providing a coating force-feeding tank for supplying a fixed amt. of coating to an electrostatic coating machine in an electrically insulated state, furnishing a coating supply port to the tank and connecting a paint feed pipe for supplying an electrically conductive coating from a coating source freely detachably to the supply port. CONSTITUTION:A specified high voltage is impressed on an electrostatic coating machine 1, an air feed pipeline 6 is connected to a coating force-feeding tank 2A, and a specified air pressure adjusted by a pressure control valve 5 is imparted to the tank 2A. A color changing valve 9A is simultaneously opened, an electrically conductive coating stored in the tank 2A is extruded at a specified flow rate corresponding to the coating discharge of the coating machine 1, and the coating is quantitatively supplied to the coating machine 1 from a manifold 8. Consequently, the high voltage impressed on the coating machine 1 is not leaked from coating sources 15A-15C for supplying the coatings of different colors and from a coating supply system consisting of a paint feed pipeline 16, etc., and the coating is satisfactorily applied.

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 multi-color electrostatic coating equipment for automobile painting that changes the paint colors of dozens of colors, the paint supply piping and paint are separated for each color of paint. There is the trouble of having to insulate the 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, recently, the global environmental conservation movement has increased,
In the painting industry as well, there are calls for restrictions on the use of organic solvents that produce pollutants such as hydrocarbons.

[Problem to be solved by the invention]

Therefore, in order to avoid recommending 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 with 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 to solve the problem]

In order to solve these problems, the present invention provides an electrostatic coating device for conductive paint that uses an electrostatic coating machine to which a high voltage is applied to apply a conductive paint. A paint pressure-feeding tank is installed in an electrically insulated state to press out paint using air pressure and supply a fixed amount of paint to an electrostatic coating machine.Each paint supply source is provided in the paint pressure-feeding tank, and each paint supply source is The present invention is characterized in that paint supply pipes for supplying conductive paint from a paint supply source are detachably connected.

In addition, when performing multi-color painting in which conductive paint is applied in different colors, multiple paint pressure-feeding tanks are installed, and the required amount of cleaning fluid stored inside is pumped out using air pressure for electrostatic painting. The cleaning liquid pressure-feeding tank that supplies the machine is also installed in an electrically insulated state, and these paint pressure-feeding tanks and cleaning liquid pressure-feeding tanks are connected to each color change valve and cleaning liquid supply valve that are installed in parallel on the manifold connected to the electrostatic coating machine. Each paint supply tank is provided with a paint supply source, and the cleaning liquid supply tank is provided with a cleaning liquid replenishment port, and conductive paint of each color is supplied from each paint supply source to each paint supply source and cleaning liquid replenishment port. It is characterized in that the paint supply pipe and the cleaning liquid supply pipe that supplies cleaning liquid from the cleaning liquid supply source are detachably connected.

[Effect]

According to the present invention, while a high voltage is not applied to the electrostatic coating machine, the paint supply piping that supplies conductive paint from the paint supply source is connected to each paint supply source of the paint pumping tank, Replenish conductive paint into the paint pressure tank.

When the required amount of conductive paint is stored in the paint pressure tank, the paint supply pipe connected to the paint supply pipe is disconnected again, the paint pressure tank is kept in an electrically insulated state, and the tank remains static. A high voltage is applied to the electrostatic coating machine, and at the same time, the conductive paint stored in the paint pressure tank is forced out using air pressure and supplied in a fixed amount to the electrostatic coating machine, and electrostatic coating using the conductive paint is started.

At this time, the high voltage applied to the electrostatic coating machine will not leak into the paint supply piping connected to the paint supply source of the conductive paint, so insulation measures should be taken for the paint supply system consisting of the paint supply source and paint supply piping. There is no need to worry about applying it.

In addition, when performing multi-color painting using conductive paint of each color stored in multiple paint pressure-feeding tanks, after painting the previous color paint, the cleaning liquid is supplied to the manifold connected to the electrostatic paint sprayer. Only the remaining previous color paint needs to be washed away from the manifold to the electrostatic coating machine using the cleaning liquid supplied by the valve, and the cleaning liquid is stored in the cleaning liquid pressure tank in advance and can be applied at the same time as the painting of the previous color paint is completed. Since the paint can be supplied, the cleaning time is shortened, and the color change time required before starting the application of the next color paint is significantly shortened.

〔Example〕

Embodiments of the present invention will be specifically described below 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, a plurality of paint pressure-feeding tanks 2A supply a required amount of conductive paint for at least one coating to the electrostatic coating machine 1 to which a high voltage of 80 to 120 KV is applied.
, 2B, and 2C, and a cleaning liquid pressure-feeding tank 3 that supplies a required amount of cleaning liquid for at least one cleaning to the electrostatic coating machine 1 are installed in an electrically insulated state.

An air supply pipe 6 that supplies high-pressure air at a required pressure from a high-pressure air supply #4 via a pressure adjustment valve 5 is connected to each of these paint pressure-feeding tanks 2A to 2C and the cleaning liquid pressure-feeding tank 3. Due to the air pressure, the conductive paint stored inside each of the paint pressure feeding tanks 2A to 2C is forced out at a predetermined flow rate depending on the paint discharge amount of the electrostatic coating machine 1, and from the cleaning liquid pressure feeding tank 3. The cleaning liquid stored inside is forced out.

In addition, each of the paint pressure-feeding tanks 2A to 2C and the cleaning liquid pressure-feeding tank 3 are connected to color change knobs 9A to 9C that are arranged in parallel on a manifold 8 that is connected to the electrostatic atomizer 1 via a paint hose 7.
It is connected to the cleaning liquid supply valve 10. Note that the manifold 8 is also provided with a cleaning air supply valve 12 that supplies cleaning air from a cleaning air supply source 11.

Further, the paint pressure feeding tanks 2A to 2C are each provided with a paint supply source 13 made of a female coupler, and the cleaning liquid pressure feeding tank 3 is provided with a cleaning liquid supply port 14 also made of a female coupler.
is provided.

And each paint supply source 1 of the paint pressure feeding tanks 2A to 2C.
3, a paint supply pipe 16 for supplying conductive paint of each color from each paint supply source 15A to 15C is detachably connected to the paint supply pipe 16 by a female coupler 17 provided at the tip thereof. The female coupler 17 is fixed to the piston rod 19 of the air cylinder 18, and moves back and forth in the direction of engagement with each paint supply source 13 made of a female coupler by the expansion and contraction of the histone rod 19. It is now possible to do so.

In addition, a cleaning liquid supply pipe 2 that supplies cleaning liquid from a cleaning liquid supply source 20 is connected to the cleaning liquid replenishment port 14 of the cleaning liquid pressure-feeding tank 3.
1 are detachably connected by a female coupler 22 provided at the tip thereof. Note that this female coupler 22 is connected to the piston rod 2 of the air cylinder 23.
4, and the piston rod 24 expands and contracts to move it forward and backward in the direction of engagement with the cleaning liquid replenishment port 14 made of a female coupler.

Furthermore, each of the female couplers has a check valve structure that is opened only when they are fitted into each other.

Next, a flow meter 25 that detects the flow rate of the conductive paint or cleaning liquid flowing through the hose 7 is installed in the paint hose 7 that connects the electrostatic coating machine 1 and the maniholt 8. Insulated signal line 2 such as optical fiber after lightning conversion
Based on the detection signal taken out through 6, the control device 2
An optical signal for pressure adjustment is output from 7 to the pressure adjustment knob 5 through an insulated signal line 28 such as an optical fiber, and the signal is photoelectrically converted and driven by the pressure adjustment valve 5, which outputs it from the high pressure air supply source 4. The air pressure supplied to each of the paint pressure-feeding tanks 2A to 2C and the cleaning liquid pressure-feeding tank 3 is adjusted.

The above is the configuration of the electrostatic coating apparatus shown in FIG. 1. Next, the operation thereof will be explained with reference to FIG. 2.

For example, when painting with conductive paint stored in the paint pumping tank 2A, a predetermined high voltage is applied to the electrostatic atomizer 1 in the state shown in FIG. The air supply pipe 6 that supplies high-pressure air is connected to the paint pressure feeding tank 2A.
At the same time, the color change valve 9A provided in the manifold 8 is opened to remove the conductive paint stored in the tank 2A. The conductive paint is forced out at a predetermined flow rate depending on the amount of paint discharged from the electrostatic paint applicator 1 , and the conductive paint is supplied in a fixed amount to the electrostatic paint applicator 1 from the manifold 8 through the paint hose 7 .

This prevents the high voltage applied to the electrostatic coating machine 1 from leaking into the paint supply system consisting of the paint supply sources 15A to 15C that supply conductive paint of each color, each paint supply pipe 16, etc.
Painting with conductive paint is performed. Therefore, there is no need to take insulating measures for these paint supply systems.

Furthermore, since high voltage does not leak into the cleaning liquid supply system consisting of the cleaning liquid supply source 20 and the cleaning liquid supply piping 21, there is no need to take insulation measures for the cleaning liquid supply system.

When painting with the conductive paint stored in the paint pressure feed tank 2A is completed, the application of high voltage to the electrostatic coating a1 is stopped and the air supply pipe 6 is switched from the paint pressure feed tank 2A to the cleaning liquid pressure feed tank 3. At the same time, the cleaning air supply valve 12 and the cleaning liquid supply valve 10 provided in the manifold 8 are opened and closed alternately, and the cleaning air supplied from the cleaning air supply #11 and the cleaning liquid pumped out from inside the cleaning liquid pressure feeding tank 3 are supplied by air pressure. The previous color paint remaining in the manifold 8, the paint hose 7, and the electrostatic atomizer 1 is discharged from the electrostatic atomizer 1 using the cleaning liquid, and is washed away.

At the same time as cleaning of the previous color paint starts, the female coupler 17 installed at the tip of the paint supply pipe 16 connected to the paint supply source 15A is connected to each paint supply source in the paint pressure feeding tank 2A using an air cylinder 18. 13, the paint supply pipe 16 is connected to each paint supply source 13, and paint is supplied from the paint supply source 15A into the paint pressure feeding tank 2A.

At the same time as the cleaning of the previous color paint is completed, the female coupler 22 installed at the tip of the cleaning liquid supply pipe 21 connected to the cleaning liquid supply source 20 is connected to the cleaning liquid supply port 14 of the cleaning liquid pressure feeding tank 3 using the air cylinder 23. A cleaning liquid supply pipe 21 is connected to the cleaning liquid replenishing port 14 of the female coupler, and the cleaning liquid is also supplied from the cleaning liquid supply source 20 into the cleaning liquid pressure feeding tank 3.

When the replenishment of the paint in the paint pressure feed tank 2A and the cleaning liquid in the cleaning liquid force feed tank 3 are completed, the paint supply pipes are connected from each paint supply source 13 of the paint force feed tank 2A and the cleaning liquid supply port 14 of the cleaning liquid force feed tank 3, respectively. 16 and the cleaning liquid supply pipe 21 to return to the state shown in FIG. Paint application can be started immediately.

Therefore, the color change time required from the end of painting the previous color paint to the start of painting the next color paint is shortened, and the painting productivity in multicolor painting is also very good.

In the above embodiment, the flow rate of paint fed to the electrostatic coating machine 1 is adjusted by varying the air pressure of the pressure regulating valve 5, but the present invention is not limited to this.

For example, the paint hose 7 may be provided with a flow control valve, and the opening degree of the valve may be varied by a signal output from the control device 27 to adjust the flow rate of the paint.

〔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 paint supply system for the conductive paint. Even a multi-color electrostatic coating device having a paint supply system for different colors has the very excellent effect of being able to perform electrostatic coating using non-polluting water-based paint without increasing equipment costs.

Insulating resin paints that consume large amounts of organic solvents also have the excellent effect of shortening the interval between finishing one coat and starting the next coat, and shortening the color change time in multi-color coatings. It is useful in that it can promote the transition from electrostatic painting using water-based paints to electrostatic painting using water-based paints.

[Brief explanation of the drawing]

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. Explanation of symbols 1 - Electrostatic coating machine, 2A, 2B, 2C - Paint pressure feeding tank, 3 - Cleaning liquid pressure feeding tank, 4 - High pressure air supply source, 8 - Manifold, 9A, 9B, 9C - Color change valve, 10 -Cleaning liquid supply valve, 13-Each paint supply source, 14-Cleaning liquid supply port, 15A, 1
5B, 15C-paint supply source, 16-paint supply piping, 20-cleaning liquid supply source, 21-cleaning liquid supply piping. Patent applicant Trinity Industries Co., Ltd.

Claims (1)

[Scope of Claims] [1] In an electrostatic coating device for coating conductive paint, which coats conductive paint with an electrostatic coating machine (1) to which a high voltage is applied, a required amount of conductive paint stored inside. A paint pressure feeding tank (2A
) is installed in an electrically insulated state, and a paint supply port (13) is provided in the paint pressure feeding tank (2A), and a paint supply source (15A) is connected to the paint supply port (13).
1. An electrostatic coating device for conductive paint, characterized in that a paint supply pipe (16) for supplying conductive paint from the source is detachably connected to the paint supply pipe (16). [2] In an electrostatic coating device for conductive paint, which applies conductive paint using an electrostatic coating machine (1) to which a high voltage is applied, the required amount of conductive paint stored inside is forced out using air pressure. A plurality of paint pressure feeding tanks (2A), (2B), (2C) supply a fixed amount of paint to the electrostatic coating machine (1), and a required amount of cleaning liquid stored inside the electrostatic coating machine (1) is pumped out using air pressure. ) are installed in an electrically insulated state, and color change valves (9A), (9B), which are installed in parallel on a manifold (8) connected to the electrostatic coating machine (1).
(9C) and the cleaning liquid supply valve (110), and each paint pressure feeding tank (2A), (2B), (2
C) and the cleaning liquid pressure-feeding tank (3), respectively.
) and a cleaning liquid supply port (14) are provided, and each color is supplied from each paint supply source (15A), (15B), (15C) to each paint supply port (13) and cleaning liquid supply port (14), respectively. A paint supply pipe (16) that supplies conductive paint and a cleaning liquid supply pipe (16) that supplies cleaning liquid from a cleaning liquid supply source (20).
21) is configured to be detachably connected to each other.