JPS6031550B2 - Cleaning method and equipment for electrostatic coating equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method and apparatus for safely and efficiently cleaning paint jet heads in electrostatic coating equipment.

In electrostatic painting equipment, when changing the color of paint, etc., it is necessary to clean the paint ejection head (hereinafter referred to as color change cleaning) where a high DC voltage is applied and the paint is sprayed in the form of a mist. It is.

For this reason, electrostatic painting equipment is often designed so that the applied voltage applied to the paint ejection head is cut off and the grounding device automatically grounds the equipment, but when changing colors and cleaning, etc. To ensure completeness, it has traditionally been the practice for a worker to enter the painting room and touch a grounding rod to the paint spray head. However, in the unlikely event that the grounding device is malfunctioning and the grounding rod is brought rapidly close to the paint launching head, a spark discharge (
Sparks are generated, which can ignite highly flammable oils such as thinner that are brought into the painting room to clean the paint projector, causing a fire. The power supply of electrostatic painting equipment is sometimes equipped with an overcurrent cutoff device, but this device takes a considerable amount of time to operate, and as shown in Figure 1, the discharge current exceeds the overcurrent cutoff device. By the time the device starts operating after a certain period of time has passed after the set current has been exceeded, the current value reaches as much as 3 hA, and sparks are usually generated. Furthermore, as long as humans are the ones bringing the grounding rod into contact with the paint ejecting head, malfunctions such as bringing the grounding rod close to the paint ejecting face (while high voltage is still applied) cannot be avoided, and in this case, the above-mentioned fire There is a particularly high risk of
Workers entering the paint room are exposed to extremely dangerous conditions. Furthermore, even if the paint ejector head is grounded, the worker himself or herself may be charged with a high voltage, and sparks may occur between the spray head and the grounding device, making it dangerous and undesirable for the worker to enter the painting room. There isn't. The present invention has been made against the background of these circumstances, and includes providing a large number of conductive pointed members on either one of the paint ejection head and the grounded earth body, and mechanically moves the paint ejection head and the earth body relative to each other. a step of causing the two to gradually approach each other at a predetermined speed with the pointed member in between by moving them, and discharging the electric charge charged on the paint ejection head without generating a spark; a step of completely removing the electric charge on the paint ejection head by bringing the paint ejection head into contact with the paint ejection head through the tip village, a step of cleaning the paint ejection head, and a step of separating the paint ejection head and the ground body by relative movement. In order to carry out the method, a grounding body which is always grounded, a mechanism for relatively moving this grounding body and the paint projectile are provided, and The grounding body includes a band-shaped grounding surface formed so as to gradually approach the paint projectile from a direction perpendicular to the direction of the relative movement when the grounding body and the paint projectile head are moved relative to each other; At least one of the ground surface and the paint ejector head is provided with a large number of point members made of a good electrical conductor, and when the ground surface and the paint ejector head are closest to each other, the two are electrically connected by the point member. The present invention provides a cleaning device that can be used for cleaning.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings.

In FIG. 2, reference numeral 1 denotes a paint ejection head, which is fixed to the tip of a support member 10 made of resin, and which is rotated in a horizontal plane by a drive device 15 including a motor. It is designed to be able to move between the painting position shown by the two-dot chain line in the figure and the cleaning position shown by the solid line, and when it is moved to the painting position, a high DC voltage is applied between it and the object to be painted W. is applied thereto, and when moved to the cleaning position, it is covered with a shroud 20 that moves in the left-right direction in the figure, and cleaning is carried out inside the shroud 20. That is, as shown in detail in FIG. 3, the paint projectile 1 includes a mini-bell 2 in which a mesh hole 2a for ejecting paint is formed, an air motor 3 for rotating the mini-bell 2, and a grounding body to be described later. It is equipped with a U-shaped contact body 5 (see Fig. 4) that can be brought into contact, and these are electrically connected to each other, and when in the coating position, a DC voltage is applied between it and the object W to be coated. , the paint supplied through the paint hose 6 is transferred to the motor 3
As the shaving gear rotates, it is fired from the pongee hole 2a of the minibell 2, and when it is in the cleaning position, the inside of the minibell 2 is cleaned by being covered with the shroud 20 and supplied with thinner, air, etc. from the shaving hair hose 8. be.

The air motor 3 is rotated by supplying and exhausting air from the hoses 7a and 7b, respectively, and thinner and the like supplied from the shaving air hose 8 are sucked and discharged from the discharge port 20a of the shroud 20. Further, the power supply device of the electrostatic coating apparatus of this embodiment is provided with an overcurrent cutoff device as in the conventional case. A grounding body 25 is disposed near the shroud 20 so as to be below the paint ejecting head 1.

This grounding body 25 is disposed in a band shape along the arc-shaped locus drawn by the contact body 5 when the paint firing head 1 is rotated, and as clearly shown in FIG. The surface is constant with respect to the moving direction (horizontal plane) of the paint ejecting head 1, except that the lower part of the contact body 5 when it is moved to the cleaning position is a horizontal ground plane (hereinafter referred to as horizontal ground plane) 26 The earth surface 27 is inclined with a relatively gentle slope at an angle of It is erected in the shape of Next, the operation will be explained.

During painting, the paint ejector head 1 is at the position shown by the two-dot chain line in FIGS. Moreover, since the minibell 2 is rotated by the air motor 3, the paint supplied from the paint hose 6 is sprayed out from the pongee hole 2a by centrifugal force and atomized, and then the electric force lines It is fired toward the object W to be coated along the direction.

When painting is completed and the applied voltage applied to the mini bell 2 is cut off, the paint ejection head 1 is rotated by the drive device 15 toward the cleaning position shown by the solid line in FIGS. 2 and 4. .

At this time, as the contact body 5 rotates, it is gradually brought closer to the inclined ground surface 27 of the ground body 25, which is gently inclined, at a very small speed determined by this slope, and the paint projectile 1 is moved to the cleaning position. When the contact body 5 is rotated up to 100 degrees, the contact body 5 is brought into contact with the wire 31 on the horizontal ground plane 26 and conducts the wire 31 to the ground body 25. As a result, any remaining charge on the paint projectile 1 is completely removed. Once the paint projectile 1 has reached the cleaning position, the shroud 2 at the position shown by the solid line in FIG.
0 to the right to the position shown by the two-dot iron line to cover the paint jet head 1, and the paint jet head 1 is cleaned by supplying thinner, air, etc. from the shaving air hose 8.

After cleaning, the shroud 20 is returned to the position shown by the solid line in the same figure, the paint ejection head 1 is rotated toward the painting position, and a paint of a different color is supplied from the paint supply device to apply this paint. The object W to be coated is coated.

The above is an explanatory view of the operation in this embodiment. According to this embodiment, the color change cleaning of the paint ejection head 1 can be carried out extremely safely and efficiently. That is, the movement of the paint ejection head 1 between the painting position and the cleaning position is performed by rotating the support part 10 in the horizontal plane,
Most of the grounding body 25 is a sloped grounding surface 2 with a gentle slope.
7, when the contact body 5 is moved in a horizontal plane, it is made to gradually approach the ground body 25 from a direction perpendicular to this horizontal plane, so that the contact body 5 can be moved while keeping the cleaning position a considerable distance away from the painting position. 5 is mechanically brought close to the inclined ground surface 27 of the grounding body 25 at a very low speed as the paint propellant head 1 is rotated towards the cleaning position, during which time the paint propellant remaining on the paint propellant head 1 is The static electricity that is present is discharged from the tips of the many wires 31 without sparks, so that the contact body 5 is then brought into contact with the wires 31 on the horizontal ground plane 26 and the static electricity is completely eliminated. In addition, in the unlikely event that the power supply unit malfunctions, the paint ejection head 1
Even if the applied voltage is not cut off when moving to the cleaning position, the current value of the discharge generated between the contact body 5 and the ground body 25 will increase as the paint ejection head 1 rotates. As shown in the figure, it rose very slowly, only 20
When it reaches 0 French A, the overcurrent cut-off device is activated. This is a current value at which no spark is generated between the contact body 5 and the ground body 25, and even if a flammable oil such as thinner is used when cleaning the paint propellant head 1, this oil The fear of catching fire is completely eliminated. Another embodiment of the invention is shown in FIG.

In the above embodiment, the tip member was a wire 31 erected upward from the ground body 25, but in this embodiment, the tip member is a strip of aluminum foil whose upper end is fixed to the contact body 5 and hangs down. It is 32.

In this case as well, as the paint ejection head 1 rotates, the lower end of the strip 32 approaches the horizontal plane on which the contact body 5 is moved from a direction perpendicular to it, and then comes into contact with the ground body 25. The same effects as in the embodiment can be obtained. Further, in the above embodiment, the grounding body 25 is provided with the inclined grounding surface 27 to reduce the substantial approach speed of the contacting body 5 to the grounding body 25 to prevent the generation of sparks. It is also possible to prevent the generation of sparks by gradually slowing down the moving speed of the paint ejection head 1 as it approaches the cleaning position, as shown by curve A in FIG. 8, without providing the ground plane 27. .

Also, without moving the paint ejection head 1, the ground body 2
The object of the present invention can also be achieved by moving the shroud 20.

Furthermore, in each of the above embodiments, the power supply device of the paint ejection head 1 is not particularly provided with a grounding device, and it is clear from the previous description that the static electricity of the paint ejection head 1 can be removed satisfactorily even with this. However, in order to further improve safety, it is desirable to provide a grounding device to the power supply device as well.

As described in detail above, according to the present invention, when the paint ejection head and the ground body are moved relative to each other after painting is completed and the paint ejection head is moved to the cleaning position, the paint ejection head and the earth body are moved at a low speed at the same time. Because they are brought closer to each other gradually, sparks are prevented from being generated due to electrical discharge, and even if a flammable oil is used to clean the paint projectile, there is no risk of it catching fire, making it extremely safe to clean the paint projectile head. This results in a cleaning effect.

[Brief explanation of drawings]

Fig. 1 is a graph showing the current value of discharge generated during static elimination in a conventional electrostatic coating device, Fig. 2 is a plan view showing an embodiment of the present invention, and Fig. 3 is a graph showing the paint ejection shown in Fig. 2. An enlarged front view of the head, FIG. 4 is a left side view of FIG. 2, and FIG.
FIG. 6 is a side view corresponding to FIG. 4 showing another embodiment of the invention; FIG. 7 is a graph showing the moving speed of the paint projectile in yet another embodiment of the invention. It is. 1: Paint launch head, 2: Mini bell, 3: Air motor, 5
: contact body, 6: paint hose, 7a, 7b: hose,
8: Shaving air hose, 10: Support member, 15
: Drive device, 20: Shroud, 25: Earth body, 26
, 27: Earth surface, 31: Wire, 32: Strip. Figure 1 Figure 2 Figure 5 Figure 7 Figure 3 Figure 4 Figure 6

Claims (1)

[Scope of Claims] 1. A paint ejection head to which a high DC voltage is applied and paint is supplied from a paint supply device and ejects the paint toward an object to be painted, and a grounded earth body. A large number of conductive point members are provided on one side, and the paint projectile head and the ground body are mechanically moved relative to each other, so that the paint projectile head and the ground body are predetermined with the point member in between. a step of gradually approaching the paint projecting head at a certain speed and discharging the electrical charge charged on the paint projecting head without generating a spark;
a step of bringing the paint projectile head into contact with the grounding body through the pointed member to completely remove the electrical charge on the paint projectile head; a step of cleaning the paint projectile head; and a step of cleaning the paint projectile head; A cleaning method for an electrostatic coating apparatus, comprising a step of separating the ground body from the ground body by relative movement. 2. A paint projectile head to which a high DC voltage is applied and paint is supplied from a paint supply device, which atomizes the paint and fires it toward the object to be coated, and an insulating support that supports the paint projectile head. An electrostatic coating device comprising: an apparatus for cleaning the paint ejector head, comprising: a ground body made of a grounded electrically conductive material; a mechanism for relatively moving the ground body and the paint ejection head; and the ground body is formed so that when the ground body and the paint launch head are moved relative to each other, the ground body gradually approaches the paint launch head from a direction perpendicular to the direction of the relative movement. a surface, and at least one of the ground surface or the paint ejection head includes a plurality of pointed members made of a good electrical conductor;
A cleaning device characterized in that when the ground plane and the paint ejecting head are in the closest position, they are electrically connected to each other by the pointed member.