JP2577902Y2 - Electrostatic coating equipment for conductive paint - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic coating apparatus for applying a conductive paint such as a water-based paint, a slurry paint, or a metallic paint by an electrostatic paint machine to which a high voltage is applied.

[0002]

2. Description of the Related Art When a conductive paint such as a water-based paint is applied by an electrostatic coating machine to which a high voltage has been applied, in order to prevent leakage of the high voltage applied to the electrostatic coating machine, the coating of the coating machine is performed. Since it is necessary to take measures against the insulation of the paint supply system (Japanese Patent Application Laid-Open Nos. 55-114366 and 56-141869), a multicolor electrostatic coating apparatus for automotive painting, in which dozens of paint colors are changed and painted. However, it is troublesome to take insulation measures for all the paint supply pipes and paint tanks for each color paint. For this reason, in automotive painting, electrostatic painting using an insulating resin paint that consumes a large amount of harmful organic solvents is still predominant, and the fact is that the use of non-polluting water-based paint is forgotten. However, recently, the global environmental conservation movement has increased, and the coating industry has been calling for restrictions on the use of organic solvents that generate pollutants such as hydrocarbons.

[0003]

Therefore, the present invention recommends the use of a water-based paint. Therefore, even if electrostatic coating is performed using a conductive paint such as a water-based paint, the paint is not required to be applied to a paint supply pipe or a paint tank. It is not necessary to take troublesome insulation measures on the supply system, and when performing multicolor electrostatic coating with the conductive paint, the cleaning time of the previous color paint can be shortened, and the previous color paint and the next color It is a technical problem to surely prevent color mixing of paint.

[0004]

In order to solve this problem, the present invention provides an electrostatic coating apparatus for coating a conductive paint with an electrostatic coating machine to which a high voltage is applied. A pump that presses out the conductive paint introduced into the paint outlet from the paint discharge port at a predetermined flow rate in accordance with the paint discharge amount of the electrostatic coating machine and supplies the same to the electrostatic coating machine is installed in an electrically insulated state. disengageably-formed coupler against the coupler provided in the paint inlet of the pump, the paint
At the tip of the supply pipe,
Is it at a specified insulation distance from the mouth coupler?
And the inner surface of the head portion of the cylinder that opens the paint discharge port is formed on a peripheral surface that gradually decreases in diameter as approaching the paint discharge port. And

[0005]

According to the present invention, when a high voltage is not applied to the electrostatic coating machine, the paint supply pipe is connected to the paint inlet of the pump, and the conductive paint is introduced into the cylinder from the paint inlet. Introduce. Then, when the required amount of conductive paint for painting is filled in the cylinder, the paint supply pipe connected to the paint inlet is separated from the paint inlet,
Make the whole pump electrically insulated.

In this state, a predetermined high voltage is applied to the electrostatic coating machine, and the conductive paint filled in the cylinder of the pump is discharged from the paint discharge port of the cylinder in accordance with the amount of paint discharged from the electrostatic painting machine. At a constant flow rate to supply a constant amount to the electrostatic coating machine, and start electrostatic coating with the conductive paint.
At this time, the pump and the paint supply pipe for supplying the conductive paint to the paint inlet of the pump are separated from each other and are electrically insulated. There is no leakage to the paint supply system for conductive paint composed of piping and the like. Therefore, it is not necessary to take troublesome insulation measures for the paint supply system, and in a multicolor electrostatic coating apparatus having a paint supply system of several tens of colors, enormous equipment costs for taking insulation measures are not required. Become.

Next, when the coating with the paint is completed by using up the conductive paint pressed out from the inside of the cylinder of the pump, the application of the high voltage to the electrostatic coating machine is stopped, and the same paint is again put into the cylinder. After filling, or in the case of a multicolor electrostatic coating apparatus, the precolor paint remaining in the cylinder is removed by washing with a washing liquid or washing air and then filled with the next color paint. At the time of this cleaning, the ordinary cylindrical cylinder easily removes the precolor paint remaining on the corner formed at the boundary between the inner peripheral wall of the cylindrical shape and the inner surface of the head portion where the discharge port is opened. Since cleaning cannot be performed, it is necessary to supply the cleaning liquid and the cleaning air over and over again in order to prevent color mixing with the next color paint, and the cleaning takes time. On the other hand, in the cylinder of the present invention, the inner surface of the head portion that opens the paint discharge port is formed on the peripheral surface that gradually decreases in diameter as approaching the paint discharge port, and paints the previous color paint remaining adhered in the cylinder. Since it can be washed and removed from the discharge port all at once, the washing time is shortened and the color mixture of the preceding color paint and the next color paint is surely prevented.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below with reference to the drawings. FIG. 1 is a flow sheet diagram showing a first embodiment of the electrostatic coating apparatus according to the present invention, FIG. 2 is a flow sheet diagram showing a second embodiment, and FIG. 3 is a flow sheet diagram showing a third embodiment.

In FIG. 1, a pump 2 for supplying a water-based paint to an electrostatic coating machine 1 to which a high voltage of 80 to 120 KV is applied is installed in an electrically insulated state, and a driving device such as a motor or an air cylinder is provided. The water-based paint introduced into the cylinder 7 from the paint inlet 6 by the piston 5 attached to the tip of the insulating shaft 4 reciprocated at 3 corresponds to the paint discharge amount of the electrostatic coating machine 1 from the paint discharge port 8. It is designed to extrude at a predetermined flow rate and to supply a fixed amount to the electrostatic coating machine 1.

At the extending end of the paint inlet 6, a female coupler 9 for opening and closing the paint inlet 6 is provided, and the coupler 9 is fixed at a fixed position. Further, the cylinder 7 is connected to the paint inlet 6 so as to be freely detachable and connected to the paint inlet 6 through the cylinder 7.
A paint supply pipe 10 for introducing a water-based paint into the paint supply pipe 10 has a rear end connected to a color changing valve device 11 and a detachably fitted with a female coupler 9 provided at a tip end of a paint inlet 6. A male coupler 12 is provided and the coupler 1
2 is fixed to the piston rod 14 of the air cylinder 13 so that the piston rod 14 can be moved back and forth from the required insulation distance toward the female coupler 9 of the paint inlet 6 fixed in position by the expansion and contraction of the piston rod 14. It has become. The female coupler 9 and the male coupler 12 have a check valve structure that is opened when fitted together. The color changing valve device 11 includes a plurality of color changing valves a, b, and c for selectively supplying water-based paint of each color, a cleaning air supply valve d for supplying cleaning air, and a cleaning liquid supply valve e for supplying cleaning liquid. Is provided.

Next, the paint inlet 6 and the paint outlet 8 are opened in the head 15 of the cylinder 7 and the head 1
5 has a conical peripheral surface 1 whose diameter gradually decreases as approaching the paint discharge port 8 opening at the center of the head portion 15.
6 is formed.

The above is the configuration of the electrostatic coating apparatus shown in FIG. 1. Next, the operation thereof will be described. Before the start of painting in which a high voltage is not applied to the electrostatic painting machine 1, the piston rod 14 of the air cylinder 13 is extended, and the male member provided at the tip of the paint supply pipe 10 fixed to the piston rod 14 is provided. The paint coupler 12 is fitted to the female coupler 9 provided at the paint inlet 6 of the pump 2, and the paint supply pipe 10 is connected to the paint inlet 6. Next, one of the color change valves a to c provided in the color change valve device 11 is opened, and a desired color water-based paint selected by the valve is opened from the paint supply pipe 10 to the paint inlet. The water-based paint is introduced into the cylinder 7 while the piston 5 in the cylinder 7 is retracted by the driving device 3 of the pump 2 while being supplied into the cylinder 7 of the pump 2 through 6.

When the cylinder 7 is filled with a required amount of water-based paint required for painting the electrostatic painting machine 1, the piston rod 14 of the air cylinder 13 is contracted and fixed to the piston rod 14. The male coupler 12 of the paint supply pipe 10 is separated from the paint inlet 6, and is retracted to the original position where the insulation distance can be maintained.

In this state, a predetermined high voltage is applied to the electrostatic coating machine 1 and a driving device 3 of the pump 2 is started, and a piston 5 connected to the driving device 3 via an insulating shaft 4 is provided. Then, the water-based paint filled in the cylinder 7 is pressed out from the paint discharge port 8 at a predetermined flow rate and is supplied to the electrostatic coating machine 1 in a constant amount, thereby starting the electrostatic coating with the water-based paint. At this time, the pump 2 that supplies the water-based paint to the electrostatic coating machine 1 and the paint supply pipe 10 that supplies the water-based paint to the cylinder 7 of the pump 2 are insulated at a required distance from each other. The high voltage applied to the electrostatic coating machine 1 does not leak to the paint supply pipe 10 or the color changing valve device 11. Therefore, troublesome insulation measures are required for the entire paint supply system such as the paint supply pipe 10, the color change valve device 11, and the paint tank and the paint pipe for supplying the aqueous paint to each of the color change valves a to c of the color change valve device 11. Need not be applied.

Next, when the water-based paint in the cylinder 7 is pressed out by the piston 5 and the painting is completed, the application of the high voltage to the electrostatic painting machine 1 is stopped, and the male paint provided in the paint supply pipe 10 is stopped. The coupler 12 is fitted again to the female coupler 9 provided at the paint inlet 6, and the cleaning air supply valve d and the cleaning liquid supply valve e of the color changing valve device 11 are kept while the piston 5 that has pressed out the paint is in the forward state. Are alternately opened and closed, and the cleaning paint and air supplied by these valves d and e are used as the aqueous paint which becomes the pre-color paint remaining in the cylinder 7 of the pump 2 and the electrostatic coating machine 1 from within the paint supply pipe 10. Are discharged from the electrostatic coating machine 1 by washing. At this time, the cleaning air and the cleaning liquid supplied into the cylinder 7 from the paint inlet 6 are discharged from the paint discharge port 8 opened at the center of the head 15 of the cylinder 7, and the inner surface of the head 15 is Paint outlet 8
Is formed on the conical peripheral surface 16 whose diameter gradually decreases as it approaches. Therefore, the pre-color paint adhered and remaining in the cylinder 7 is completely removed by the cleaning air and cleaning liquid without leaving any color. Therefore, it is possible to reliably prevent the color mixture of the previous color paint and the next color paint, and to reduce the cleaning time because it is not necessary to repeatedly supply the cleaning air and the cleaning liquid to prevent the color mixture. it can. Further, since the cleaning liquid remaining in the cylinder 7 can be completely removed by the cleaning air, the problem that the cleaning liquid is mixed with the next color paint and the viscosity of the paint is reduced can be prevented.

Next, when the washing of the pre-color paint is completed, the water-based paint to be the next color paint selected by the color change valves a to c of the color change valve device 11 is transferred to the cylinder while the piston 5 in the cylinder 7 is retracted. 7 is introduced. When the cylinder 7 is filled with a required amount of paint, the paint supply pipe 10 connected to the paint inlet 6 is cut off, and a high voltage is again applied to the electrostatic coating machine 1 to apply the next color. Start electrostatic painting with paint.

In order to further enhance the cleaning effect in the cylinder 7, the front surface of the piston 5 is gradually reduced in diameter toward the inner surface of the head portion 15 formed on the conical peripheral surface 16 as shown in FIG. The front surface of the piston 5 and the inner surface of the head portion 15 are formed to face each other with a certain gap 18 as shown by a chain line, and cleaning air and a cleaning liquid are supplied into the gap 18. I just need. That is, in FIG. 2, the front surface of the piston 5 is formed in a tapered surface 17, and the cleaning air is supplied to a gap 18 formed between the tapered surface 17 and a conical peripheral surface 16 forming the inner surface of the head portion 15. A supply port 19 for supplying the cleaning liquid is opened, and the supply port 19 is connected to a pipe 24 that is switched to a cleaning air supply source 22 and a cleaning liquid supply source 23 by switching valves 20 and 21. The cleaning liquid supply source 23 is configured to pump the cleaning liquid stored in a tank 25 installed in an electrically insulated state by a pump 26. As a result, the cleaning liquid supplied into the cylinder 7 flows toward the paint discharge port 8 while traveling along the inner wall of the cylinder 7 and the surface of the piston 5, and adheres to the cylinder 7 by the flow of the cleaning liquid. The paint is effectively wiped away.

In order to further enhance the effect of cleaning the inside of the cylinder 7, as shown in FIG. 3, the piston 5 which is advanced and retracted by the insulating shaft 4 is provided with an oblique line along the circumferential direction of the tapered surface 17 from the inside thereof. A plurality of ejection holes 27 are opened, and a pipe 28 for supplying the cleaning air and the cleaning liquid is protruded therein, and the cleaning air is supplied to the pipe 28 by the switching valves 20 and 21 as in FIG. By connecting a pipe 24 switched to a supply source 22 and a cleaning liquid supply source 23,
The cleaning liquid and the cleaning air may be jetted from each jetting hole 27. That is, the cleaning liquid spouted from each spouting hole 27 that opens obliquely along the circumferential direction of the tapered surface 17 of the piston 5 is flushed with the tapered surface 17 of the piston 5 and the cylinder 7.
As the vortex flows toward the paint discharge port 8 while forming a vortex with the peripheral surface 16, the effect of wiping the paint adhered in the cylinder 7 is further enhanced, so that the cleaning time is remarkably reduced, And the color mixture of the next color paint is also reliably prevented. If the cleaning air is jetted after the jetting of the cleaning liquid, the cleaning liquid remaining in each jetting hole 27 is also wiped.

[0019]

[Effects of the Invention] As described above, according to the present invention, even when performing electrostatic coating with a conductive paint, it is not necessary to take troublesome insulation measures for the paint supply system such as the paint supply pipe and the paint tank. In addition, when performing multicolor electrostatic coating with the conductive paint, it is possible to shorten the cleaning time of the preceding color paint and also to surely prevent the color mixing of the preceding color paint and the next color paint. It has a very good effect.

[Brief description of the drawings]

FIG. 1 is a flow sheet diagram showing a first embodiment of an electrostatic coating apparatus according to the present invention.

FIG. 2 is a flow sheet diagram showing the second embodiment.

FIG. 3 is a flow sheet diagram showing a third embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Electrostatic coating machine 2 ... Pump 5 ... Piston 6 ... Paint inlet 7 ... Cylinder 8 ... Paint discharge port 10 ... Paint supply pipe 15 ... Head part 16: peripheral surface 17: tapered surface

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-298374 (JP, A) JP-A-63-310671 (JP, A) JP-A-3-262558 (JP, A) 14655 (JP, U) Actual opening 52-65164 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) B05B 5/025-5/16

Claims (2)

(57) [Scope of request for utility model registration] An electrostatic coating apparatus for applying a conductive paint by an electrostatic coating machine (1) to which a high voltage is applied, wherein a conductive paint introduced into a cylinder (7) from a paint inlet (6). A pump (2) which presses out the paint from the paint discharge port (8) at a predetermined flow rate in accordance with the paint discharge amount of the electrostatic paint coater (1) and supplies a fixed amount to the electrostatic paint coater (1) is electrically insulated. And a coupler detachably formed with respect to a coupler (9) provided at the paint inlet (6) of the pump (2).
(12) is attached to the tip of paint supply pipe (10)
With the coupler (9) of the paint inlet (6)
From the position separated by the specified insulation distance
The inner surface of the head portion (15) of the cylinder (7), which is provided so as to be capable of moving forward and backward , and which opens the paint discharge port (8), gradually decreases in diameter as it approaches the paint discharge port (8). An electrostatic coating device for conductive paint, which is formed in 16). 2. The pump (2) is adapted to press the conductive paint in the cylinder (7) with a piston (5), and the front surface of the piston (5) is connected to the cylinder (7). 2. The electrostatic coating apparatus for a conductive paint according to claim 1, wherein the taper surface (17) has a diameter gradually reduced toward an inner surface of the head portion (15).