JPH0641642Y2 - Special spray device for electrostatic spraying - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to an electrostatic coating circle in which a paint is sprayed in a circular shape by compressed air and is sprayed on an object by utilizing the electrostatic effect of a high voltage. The present invention relates to a spray device exclusively for blowing.

[Prior Art] A spray gun that uses static electricity requires a finer atomization because it uses the attractive force of static electricity to apply it to the object to be coated. You don't need much momentum to move things. Therefore, in order to improve the coating efficiency, an atomizer having a dedicated pattern for round blowing that produces finer particles is often used. Most of the spraying devices for this type of round spray spray the paint in a thin film state from an annular slit and make compressed air collide with this thin film so that a fine mist can be obtained. To be Fine particles tend to become finer as the ejected thin film becomes thinner, and therefore the diameter of the annular slit which is the paint ejection opening is also made relatively large.

[Problems to be solved by the invention] In the case of such a spray device for exclusive use of round spraying, the center of the annular slit becomes a closed space due to the air flow at the time of spraying from the tip of the paint nozzle to the point beyond the negative pressure of the center. A space is generated. As a result, the surrounding paint atomization particles are entrained in the central negative pressure space together with the air to generate a vortex, which causes instability of the spray pattern and adhesion of the paint particles.

Therefore, these adhering paints are sometimes blown off to stain the surface of the paint or to block a part of the ejection port.

An object of the present invention is to solve these problems and to obtain a spray device for electrostatic spraying which can maintain a stable spray state.

[Means for Solving the Problems] In order to solve the above problems, the present invention has a charging electrode at the center and is formed by an annular slit formed on the outer side of the charging electrode and opening forward. A spray nozzle for spraying the paint in a cylindrical shape from the annular slit, and a conical slit for blowing air that opens further to the outer periphery thereof are provided, and compressed air is ejected from the conical slit for blowing air toward the front center. In a spray device exclusively for round spraying for electric coating, a core having the same shape as a central negative pressure space formed inside the streamline of an air jet ejected from the conical slit toward the front center at the center tip of the paint nozzle. It is characterized in that a spraying device exclusively for round spraying for electrostatic coating is formed.

[Operation] The air jetted from the conical slit becomes a flow that converges in the center, and streamlines are formed toward the virtual position where the air intersects. Therefore, the portion inside this streamline is absorbed by the flow and forms a vacuum, that is, a central negative pressure space,
The surrounding air and floating mist are sucked, and entrainment vortices are generated, but the central negative pressure space part of this inner part has a conical surface at the tip so that it has the same shape as the central negative pressure space part. Since the structure of the paint nozzle has the core having the shape, the central negative pressure space is not formed. Therefore, the adhesion to the spray device is prevented.

[Embodiment] FIG. 1 is a sectional view of an electrostatic round-blowing spray device showing an embodiment of the present invention. The spray gun is detachably attached to the tip 1 of the main body of the spray gun, and a paint nozzle 2, an air nozzle 3 concentrically screwed to the outside thereof, and an air cap 4 are covered.
It is attached to the tip 1 of the main body.

The tip of the paint nozzle 2 is blocked by the core 6, and the paint is sent from the inside through the communication hole 7 to the outside of the core 6, which is the projecting portion. An air nozzle 3 is attached to the outer periphery of the core 6 while maintaining an annular skimmer 8, and the paint is ejected from the skimmer 8.

As shown in an enlarged view in FIG. 2, the blown air is discharged from a slit 9 having a conical surface that converges toward the center at the same annular outlet between the outer periphery of the air nozzle 3 and the inner surface 41 of the air cap 4. Gush out. A flow path 12 such as a spiral groove is formed on the upstream side of the slit 9 so that the air is ejected at an angle with respect to the central axis so that the velocity distribution toward the front becomes small.

The jetting angle of the blowing air differs depending on various conditions, but it is usually a cone angle of about 90 °. On the other hand, the tip of the core 6 has a conical taper 10, and its angle is formed in the same shape as the central negative pressure space portion formed inside the streamline of the blowing air, which is slightly smaller than the cone angle of the slit 9. It is formed with an acute angle. Therefore, when the paint is sprayed from the annular 8 slit and the compressed air is sprayed from the conical slit 9, the central negative pressure space portion is not formed by the core 6, and the paint adhesion can be eliminated.

Further, what is provided at the center of the tip of the core 6 is
The electrode pin 11 is charged with a high voltage, which charges the paint and forms an electric field on the object to be coated. It is desirable that the tip of the electrode projects to the atomizing portion, but in the embodiment, the tip of the core 6 is located close to the atomizing portion, so that it is only slightly projected. Therefore, the structure is such that the electrode pin 11 is protected from an accidental operation error.

[Effects of the Invention] As described above, the present invention is a spray device for electrostatically spraying round spray, in which the paint sprayed in a cylindrical shape is atomized by the air sprayed so as to converge in a conical shape from an oblique direction. Since the substantially conical core having the same shape as the central negative pressure space portion generated at the tip of the coating nozzle of the round blowing cap forming the circular pattern is provided, the generation of the central negative pressure space portion can be prevented. Therefore, the stable paint is sprayed without entraining the scattered paint. As a matter of course, the paint adhered by the entrainment is not released at the time of jetting and does not scatter on the painted surface, which leads to stabilization of the quality as a whole. In addition, the core of the tip of the paint nozzle comes close to the tip of the electrode pin, which is located near the center of atomization.
The protruding portion of the electrode pin becomes smaller and can also serve as protection.

[Brief description of drawings]

FIG. 1 is a sectional view of a spraying device for a round-blown electrostatic gun according to an embodiment of the present invention. FIG. 2 shows an enlarged view of the tip of FIG. 1 ... Body tip 2 ... Paint nozzle 3 ... Air nozzle 4 ... Air cap 6 ... Core 8 ... Annular skimmer 9 ... Slit

Claims (1)

[Scope of utility model registration request] 1. A charging electrode 11 is provided at the center, and is formed by an annular slit formed on the outside thereof and opening forward.
A coating material jetting port 8 from which the coating material is jetted in a cylindrical shape from the annular slit, and a blowing air conical slit 9 opening to the outer periphery thereof are provided, and compressed air is directed from the blowing air conical slit 9 toward the front center. In the spray device for spraying round spray for electrostatic coating, at the center tip of the paint nozzle 2,
A spraying device for electrostatic spraying, which comprises a core 6 having the same shape as a central negative pressure space formed inside a streamline of an air jet ejected from the conical slit 9 toward the front center.