JPS59228960A - Rotary atomization electrostatic painting device - Google Patents

Abstract

PURPOSE:To mix thoroughly paints and to permit easy color changing of the paints by disposing a pair of spraying nozzles in an annular groove of an atomzing head and injecting a main material from one of said nozzles and a hardener from the other at the same instant. CONSTITUTION:Respective press feed pumps 16a, 16b are first operated and regulators 15a, 15b are so adjusted that the paints to be coated are supplied at the rates meeting the amt. to be coated in the case of mixing the main material in a main material tank 17a and the hardener in a hardener tank 17c at 2:1 ratio. The rotating speed of an atomizing head 3 is then increased and a negative high voltage is impressed on the head 3. When stop valves A, C are simultaneously opened, the main material and hardener are simultaneously supplied from the repsective corresponding ejection nozzles 7, 8 into an annular groove 5 and the two materials are thoroughly mixed and agitated to a paint by the high speed revolution of the head 3. The stop valves are changed and the nozzle 7, the groove 5, etc. are washed in the case of using a paint of another color.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a rotary atomization electrostatic coating apparatus.

BACKGROUND ART Conventionally, so-called two-component paints have been known in which a paint is formed by mixing a base agent and a curing agent.

After mixing the base agent and curing agent, the viscosity of these two-component paints gradually increases over time, making it difficult to obtain a good painted surface. Therefore, when using such two-component paints, use them as much as possible. It is preferable to mix the base resin and the curing agent immediately before mixing. To this end, conventional paint injection nozzles have a double-tube structure, with the opening end of the inner tube slightly retracted from the open end of the outer tube, so that, for example, the curing agent is jetted from the open end of the inner tube and supplied through the inside of the outer tube. A coating gun is known in which a base agent is mixed with a curing agent jetted from an open end of an inner tube, and the mixture is jetted from an open end of an outer tube. However, with this paint gun, when the mixing ratio of the base resin and hardener is small (1:1 or 2:1), it is difficult to mix the base resin and hardener uniformly, so it is difficult to obtain a good painted surface. It has become difficult. Furthermore, there is a known painting method in which a pair of paint guns are installed side by side and the main agent sprayed from one paint gun and the hardening agent sprayed from the other paint gun collide and mix with each other. If this method is used, there is a problem that not only does the size of the entire coating apparatus become large, but also that the base resin and the curing agent cannot be mixed sufficiently. Another coating method is known in which a base agent and a curing agent are mixed together using a mixer provided separately, and the thus formed coating material is ejected from a coating gun. However, in this coating method, since a separate mixer must be provided, the overall size of the coating apparatus increases and the manufacturing cost of the coating apparatus increases. Furthermore, when such a mixer is used, it is necessary to clean the mixer when changing the paint color, but it is practically impossible to clean the mixer in a short time, so it is difficult to clean the mixer when changing the paint color. The problem is that it cannot be done.

OBJECTS OF THE INVENTION The object of the present invention is to provide a rotary atomization electrostatic coating device that has a simple structure, can sufficiently mix a base agent and a curing agent, and can easily change the color of the paint. .

Structure of the Invention The structure of the present invention includes a cup-shaped inner circumferential surface around the axis formed on the front surface of the N-head, an annular groove formed on the back surface around the axis, and a radius from the inner circumferential surface of the annular groove. In a rotary atomizing electrostatic coating device equipped with a paint outflow hole extending outward to the cup-shaped inner circumferential surface, a pair of injection nozzles are arranged in an annular groove of a spray head, and a main agent is sprayed from one injection nozzle. This is because the curing agent is simultaneously injected from the other injection nozzle.

Referring to the embodiment drawings, 1 is a rotary atomizing electrostatic coating device main body;
Reference numeral 3 indicates a rotating shaft driven by a drive device (not shown), and 3 indicates a spray head fixed to the tip of the rotating shaft 2. A negative high voltage is applied to the spray 1i113. spray head 3
has a cup-shaped inner circumferential surface 4 formed around the axis on its front surface, and an annular groove 5 formed around the axis on its back surface. A large number of paint outflow holes 6 extending radially outward are formed at the innermost part of the inner peripheral surface of the annular groove 5, and these paint outflow holes 6 are smoothly connected to the cup-shaped inner peripheral surface 4.

The rotary atomization electrostatic coating device main body 1 includes a pair of injection nozzles 7.8.
The paint jetting ports 9,1 of these jetting nozzles 7.8
0 is located within the annular groove 5. The injection nozzle 7 is connected to the main passage 12 of the color switching valve 11, and the injection nozzle 8 is connected to the main passage 12 of the color switching valve 11.
It is connected to the main passage 14 of No. 3. The main passage 12 is the main passage 12
The main passage 14 has branch roads C, e, and g branched from the main passage 14. The branch road a is connected to the first base agent supply device I via the on-off valve A, and the branch road A is connected to the second base agent supply device I via the on-off valve B. Further, the branch road C is connected to the curing agent supply device (2) via an on-off valve C. Each main agent supply device■
and ■ are regulators 15 that control the supply amount of the main agent, respectively.
a, 15b, and base agent pressure pumps 16a, 16b.
and base agent tanks 17a and 17b, in which base agents of different colors are accumulated, respectively. On the other hand, the curing agent supply device (2) also includes a regulator 15c that controls the amount of curing agent supplied, and a curing agent pressure pump 16.
c, and a curing agent tank 17c. Also, branch road d
, e are connected to the cleaning liquid tank 19 via the corresponding on-off valves, E and the cleaning liquid pressure pump 18, and the branch roads f
.

g is connected to the compressed air supply pump 20 via corresponding on-off valves F and G, respectively.

Next, for example, the main agent in the main agent tank 17a and the hardening agent tank 1
A case will be described in which a paint is formed by mixing 7c with a curing agent at a ratio of 2:1. In this case, the main agent pressure pump 16a and hardener pressure pump 16c are first activated, and the amount of paint to be coated is, for example, 300cc/
If the curing agent is 200 cc/min, each regulator 15a, 15c is adjusted so that the amount of the main agent passing through the regulator 15a is 200 cc/min, and the amount of curing agent passing through the regulator 15c is 100 cc/min. Next, the rotation speed of the spray head 3 is increased, and a negative high voltage is applied to the spray head 3. Then, the on-off valves A and C are opened simultaneously, so that the base agent and the curing agent are simultaneously supplied into the annular groove 5 through the corresponding injection nozzles 7.8. At this time, since the jet N head 3 is rotating at a high speed, the base resin and curing agent are sufficiently mixed and stirred in the annular groove 5, so that the paint in which the base resin and curing agent are sufficiently mixed is poured into the annular groove 5. is formed in Next, this paint flows out onto the cup-shaped inner circumferential surface 4 through the paint outflow hole 6 due to the centrifugal force generated by the rotation of the spray M3, and then forms a thin liquid film on the cup-shaped inner circumferential surface 4 and spreads out into the cup-shape. It reaches the tip of the inner peripheral surface 4. As mentioned above, a high negative voltage is applied to the spray head 3, and therefore, the paint that spreads in a thin film form from the tip of the cup-shaped inner peripheral surface 4 due to the centrifugal force generated by the rotation of the spray head 3 has a negative charge. becomes a charged spray. usually,
Since the surface to be painted is at zero potential, the paint spray is attracted toward the surface by electric force, thereby coating the surface.

When painting is completed, on-off valves A and C are closed, and the injection
The rotational speed of the head 3 is reduced and the application of the negative high voltage is stopped. Next, when painting another color of paint, that is, the main material in the main material tank 17b and the curing agent tank 17c.
When the curing agent in the main passage 12. Annular groove 5. The paint outlet hole 6 and the like are cleaned. In addition, the injection nozzle 8
Since only the hardening agent is supplied from the main passage 14, the spray nozzle 8, etc., can be cleaned from time to time as needed.

Effects of the invention Since the base resin and curing agent are mixed in the annular groove of the jet N head that rotates at high speed, the base resin and curing agent can be sufficiently mixed, and a uniform paint can thus be obtained. An extremely good painted surface can be obtained.

Further, since it is only necessary to add another injection nozzle to the conventional injection nozzle, there is an advantage that the rotary atomization electrostatic coating apparatus can be manufactured easily. Furthermore, it has the advantage that it can be coated with paints of various colors and that cleaning work at that time is also extremely easy.

[Brief explanation of drawings]

The figure is an overall view of a rotary atomization electrostatic coating apparatus according to the present invention. 3... Spray head, 4... Cup-shaped inner peripheral surface, 5... Annular groove, 6... Paint outflow hole, 7, 8... Injection nozzle.

Claims (1)

[Claims] A spray head has a cup-shaped inner peripheral surface around the axis formed on the front surface, an annular groove around the axis formed on the back surface, and a cup-shaped inner surface extending radially outward from the inner peripheral surface of the annular groove. In a rotary atomizing electrostatic coating device equipped with a paint outflow hole extending to the peripheral surface, a pair of injection nozzles are arranged in the annular groove of the spray head, and the main agent is applied from one injection nozzle and cured from the other injection nozzle. A rotary atomizing electrostatic coating device that sprays agents simultaneously.