JPS6158231B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an air atomizing automatic electrostatic coating gun that atomizes liquid paint and charges it with an electrode to which a high voltage is applied.

Conventionally, in air atomizing automatic electrostatic coating machines that charge atomized paint and spray it onto the object to be coated, there is a gap between the paint passage formed in the gun body and the automatic valve device that feeds and stops the paint. The insulating paint conduit connecting the
It was located outside the gun body so that it could be easily attached, detached, and replaced. This is because when painting solid paints that generally have high viscosity and paint resistance,
This is because when applying a metallic paint with low viscosity and paint resistance, it is necessary to select and replace the paint conduit as appropriate depending on the characteristics of each paint. For example, when electrostatically painting metallic paint, which is a non-conductive paint with a low paint resistance value, the metal pigments in the paint may form a chain state due to the approach of a ground object to the paint conduit, etc. The so-called pearl chain phenomenon was likely to occur, in which the high voltage applied to the paint pipe escapes to the grounded paint tank, etc., making it impossible to perform electrostatic painting. In order to maintain this condition, the paint conduit had to be made smaller in diameter and longer than in the case of solid paint. Furthermore, the paint conduit located outside the gun body must be sufficiently grounded, especially in the case of metallic paints, as the proximity of ground objects to the paint conduit can easily cause dielectric breakdown (sparks, etc.) of the conduit. Since the distance from the object and the electrical insulation must be maintained, materials with high electrical dielectric strength must be used.
Further, special consideration has been required for the piping so that the distance between the paint conduit and the grounded object can maintain sufficient electrical insulation.

In addition, in conventional equipment, the automatic valve device for paint is installed outside the gun body and separate from the gun body, which, combined with the arrangement of the conventional paint conduit mentioned above, increases the size of the equipment. However, it is inconvenient to handle and is prone to accidents such as fire.

The purpose of the present invention is to eliminate the various drawbacks of the prior art described above, to create an air-conditioning system that is small and easy to handle, that can be coated properly with any paint, and that can ensure high safety against fire. The purpose of the present invention is to provide an atomizing automatic electrostatic coating gun.

In the present invention, the configuration of the first invention includes a paint charging high voltage application part, a high voltage supply part electrically connected to the paint charging high voltage application part, a paint supply path, and an air supply part in the gun body. In the air atomizing automatic electrostatic painting gun, the main part of the gun body is formed of an electrically insulating material, and the high voltage supply section and the air supply are connected to the part formed of the electrically insulating material. A paint conduit storage chamber is formed surrounding the paint conduit storage chamber, and a coiled paint conduit constituting a part of the paint supply path is stored in the paint conduit storage chamber.

With this configuration, the paint conduit is stored in a coiled form in the paint conduit storage chamber covered with electrically insulating material, so its length can be ensured and sufficient insulation can be obtained. Therefore, it is possible to completely prevent the pearl chain phenomenon, dielectric breakdown, and generation of sparks that conventionally occur in the application of metallic paints.

The structure of the second invention is such that, in addition to the structure of the first invention, a grounded automatic valve device is interposed at the end of the paint supply section, and the operation of the first invention,
In addition to the effectiveness, the overall device is smaller and easier to install and handle.

Hereinafter, one embodiment of the present invention will be explained with reference to FIG. 1, which shows a central cross section of the gun body, and FIG. 2, which is cut at the point indicated by the - line in FIG. do.

The gun body 1 of the air atomization type automatic electrostatic coating gun includes a front member 1a made of an electrically insulating material and a rear member 1b also made of an electrically insulating material, which are fitted together and integrated, and the rear end of the rear member 1b. A conductive part 2 for grounding is attached to the part. An air nozzle 3 is fastened and fixed to the tip of the front member 1a by an annular fastening member 3a, and a needle-like electrode 4 as a high voltage applying section for charging the paint protrudes from the tip of the air nozzle 3. The needle-like electrode 4 is connected at its base end to an electrode guide 6 which is press-fitted via a spring to the tip of a high-voltage electrode rod 5 serving as a high-voltage supply section. The structure of the high voltage electrode rod 5 is made of a resin insulating material with a high resistance inside.
For example, a cable for applying a high voltage of about -60 KV is connected from a power source (not shown) to the needle electrode 4 through a high resistance inside the high voltage electrode rod 5. The needle-like electrode 4 is insulated from the part where the paint sprayer is attached to a reciprocator or the like and the ground conductive part 2. Further, the high voltage electrode rod 5 is inserted into the electrode rod storage hole 1c formed in the gun body 1 and the grounding conductive part 2.
and is housed and fixed within 2a. Gun body 1
An air passage 1d is also formed inside the gun body 1, and the air passage 1d branches into an air passage 1d' for paint atomization and an air passage 1d'' for controlling a coating pattern. 1d'' is an air passage. The pipe member 1d'' is attached and fixed so as to straddle a paint conduit storage chamber 1f, which will be described later. 1d indicates a joint that communicates with the air passage 1d. 7 is a needle valve for controlling the coating pattern, and the needle valve 7 connects its tapered end 7a to the air passage 1.
d'' and is screwed into the gun body 1 so that it can move forward and backward.As a result, by moving the needle valve 7 back and forth, the flow rate of air flowing through the air passage 1d'' changes, allowing the desired coating pattern to be created. can be changed to . Further, the air passing through the air passage 1d' reaches the air nozzle 3, passes through an orifice provided there, and atomizes the paint as it exits.

On the other hand, a paint passage 1e is formed in the gun body 1, and a coiled paint conduit 8 is interposed in the middle of the paint passage 1e. Coiled paint conduit 8
is a paint conduit storage chamber 1 formed in the gun body 1.
f, one end of the paint conduit 8 communicates with the paint inlet 9a of the paint communication member 9, and the paint conduit 8
The other end communicates with the paint discharge port 9b of the paint communication member 9. The paint communication member 9 constitutes a part of the paint conduit 8, and is housed and fixed within the gun body 1 in such a manner that it straddles the paint conduit storage chamber 1f. The paint communication member 9 forms part of the paint channel, but a closure is formed in the middle of the fluid passage, the passages on both sides of this closure being communicated only via the coiled paint conduit 8 . One end 1e' of the paint passage 1e opens at the side surface of the gun body 1 and forms a paint supply port.
An automatic valve device 10 is interposed in the paint passage 1e, and a valve stem 10a of the automatic valve device 10 is located opposite to a valve seat portion 10b formed in the paint passage 1e. A piston 10c is connected to a nut 10d at the end of the valve stem 10a.
The piston 10c is fixed by the gun body 1.
The valve is housed in a cylinder portion 10e formed within the cylinder portion 10e, and is constantly urged by a compression coil spring 10f in a direction to the left in the figure to close the valve. The automatic valve device 10 may be a pneumatically operated on/off valve or a check valve. 10g is a sealing member interposed between the paint passage 1e and the automatic valve device 10, and the sealing member 10g is pressed and fixed by a compression coil spring 10h. The compression coil spring 10h is positioned with one end thereof in contact with the lid member 10i. A cylinder part 10 is provided on the side of the gun body 1.
An air supply/discharge hole 10i is formed to communicate with the interior of e.
By introducing air into the cylinder portion 10e (between the piston 10c and the lid member 10i) from the air supply/discharge hole 10j, the piston 10c moves to the right in the figure against the elastic force of the compression coil spring 10f. However, the paint passage 1e is opened. The paint is then ejected to the outside through an orifice of a paint nozzle (not shown). On the contrary, the cylinder part 10
If the air supplied to e is discharged, piston 1
0c is moved to the left in the figure by the elastic force of the compression coil spring 10f, and the paint passage 1e is closed. 2b is an air vent hole formed in the grounding conductive part 2 and communicating with the inside of the cylinder part 10e.

Note that 11 is a tapered bolt for closing a hole drilled when processing the paint passage 1e, 12 is an air sealing tube member, and 13 is a screw member for fixing the sealing tube member.

The action will be explained below.

When discharging paint, when air is supplied from the air supply/discharge hole 10f of the automatic valve device 10, the piston 1
0c presses the compression coil spring 10f to the right, thereby causing the valve stem 10a to press against the piston 10.
It retreats forward c and leaves the valve seat portion 10b, thereby communicating one end 1e' of the paint passage with the paint inlet 9a. After that, the paint reaches the paint inlet 9a of the paint communication member 9 from 1e', further circulates through the paint conduit 8, and passes through the paint passage 1e from the paint outlet 9b.
reaching the paint channel in which the electrode guide 6 is housed;
It is further discharged through a paint nozzle (not shown). Moreover, in order to stop the discharge of paint, the valve rod 10a may be brought into contact with the valve seat portion 10b by exhausting the air supplied from the air supply/discharge hole 10j. At the same time, air is supplied into the air passage 1d, and this air is ejected at predetermined locations of the air nozzle 3 through the paint atomizing air passage 1d' and the painting pattern control air passage 1d'', respectively. Then, the paint is atomized by the air nozzle 3 by the air ejected from the paint atomizing air passage 1d', and a corona is generated between the needle electrode rod 4 to which high pressure is applied and the grounded object to be coated. When passing through the discharge field, it is charged and sprayed and applied to the object to be coated (not shown).The air blown out from the air passage 1d'' for controlling the coating pattern converts this atomized paint into the desired coating. Used to set patterns.

On the other hand, in this coating state, the atomized paint is transferred to the needle electrode rod 4 at the discharge port at the tip of the gun.
However, in the case of solid paint, which is often used in industrial painting, the resistance value is high, so the paint passage 1e,
Through the paint in the paint conduit 8, the ground conductive part 2
There is no possibility that the automatic valve device 10 which is in contact with the ground and in a grounded state is electrically connected and cannot perform electrostatic coating. Furthermore, even in the case of metallic paints, where a grounding object approaches the paint conduit, a pearl chain phenomenon occurs and conduction occurs in the grounding conductive part, making it impossible to perform electrostatic painting. Since it is covered with an insulating material, it is less likely to cause a pearl chain phenomenon even if a grounded object comes into contact with it. Above all, by winding the paint conduit 8 several times, the metal content in the paint can be reduced. Since the uniform dispersion state is maintained, the pearl chain phenomenon does not occur, and electrostatic coating can be performed satisfactorily and safely even though the automatic valve device is grounded.

In this embodiment, since the second invention is also included, the automatic valve device 10 is described as being built-in, but it goes without saying that it may be installed near the painting gun (also in this case, the automatic valve device 10 Even in this case, the paint conduit 8 is mostly wound and housed within an electrically insulating member, so conventionally, a long paint conduit was not stretched outside, especially for metallic coating. This method previously required a vast installation space due to electrical constraints during installation, but this space can be reduced to almost zero, and electrostatic coating can be performed well.

Further, in this embodiment, the paint conduit 8 can be replaced by fitting and disengaging the front member 1a and the rear member 1b, but the paint conduit can be used for both metallic paint and solid paint. It is not necessarily necessary to replace it, and it goes without saying that it may be molded to improve electrical insulation in some cases.

Further, a metal conductive member 2 for grounding is provided, but this is to keep the built-in metal automatic valve device 10 in a grounded state for safety, and the automatic valve device is externally mounted. In this case, even if it is a non-conductive member, it will not cause any trouble in painting.

Further, when the automatic valve device is externally packaged, the intermediate portion between the wound paint conduit and the automatic valve device may be short-circuited to earth using a joint or the like.

As explained above, according to the air atomizing automatic electrostatic painting gun of the present invention, since the long paint conduit is wound so as to be integrated with the painting gun and covered with an electrically insulating material, the installation space is reduced. It can be made extremely small, miniaturized, and can be coated well with any paint.

If the automatic valve device is housed in the gun body, the entire device can be further miniaturized, and can be easily installed and handled.

In addition, the hose inside the gun is made of resin insulating material, and since there is no ground potential near it and it is surrounded by insulating material, special consideration must be given to the insulation of the piping. This significantly increases safety. Therefore, there is no need to use materials with high electrical dielectric strength, and since the occurrence of the pearl chain phenomenon can be prevented, high pressure will not return to the external paint piping leading from the paint supply source to the gun body. Similarly to the piping inside the gun, there is no need to give special consideration to the paint piping.

Furthermore, whereas a long paint conduit would be exposed and come close to a ground object, causing sparks and causing a fire, according to the present invention, most or all of the paint conduit is inside an electrically insulating member. Because it is housed, it also has the effect of preventing fires from occurring due to sparks.

[Brief explanation of the drawing]

FIG. 1 is a central cross-sectional view of a main part of an air atomizing automatic electrostatic coating gun of the present invention, and FIG. 2 is a cross-sectional view taken along the line - in FIG. 1 and viewed from the opposite side. 1... Gun body, 1a... Front member, 1b...
Rear member, 2... Arm conductive part, 3... Air nozzle, 4... Needle electrode, 5... High voltage electrode rod, 6...
...Electrode guide, 1d...Air passage, 1e...Paint passage, 8...Paint conduit, 1f...Paint conduit storage chamber, 10...Automatic valve device.

Claims (1)

[Claims] 1. A high voltage application section for charging paint in the gun body;
In the air atomizing automatic electrostatic painting gun, which is provided with a high voltage supply section that conducts to the high voltage application section for charging the paint, a paint supply path, and an air supply path, the main part of the gun body is made of an electrically insulating material. At the same time, a paint conduit storage chamber surrounding the high voltage supply section and the air supply path is formed in the portion formed of the electrically insulating material, and one of the paint supply paths is formed in the paint conduit storage chamber. An air atomizing automatic electrostatic painting gun characterized by housing a coiled paint conduit forming a part. 2 Inside the gun body, there is a high voltage application part for charging the paint,
In the air atomizing automatic electrostatic painting gun, which is provided with a high voltage supply section that conducts to the high voltage application section for charging the paint, a paint supply path, and an air supply path, the main part of the gun body is made of an electrically insulating material. At the same time, a paint conduit storage chamber surrounding the high voltage supply section and the air supply path is formed in the portion formed of the electrically insulating material, and one of the paint supply paths is formed in the paint conduit storage chamber. An air atomization type automatic electrostatic coating system, which houses a coiled paint conduit constituting a part of the paint supply path, and a grounded automatic valve device is interposed at the end of the paint supply path. gun.