JPH0338907B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is an electrostatic coating machine having an atomizing head to which a high voltage is applied and which is driven to rotate at high speed. The present invention relates to a color change cleaning method for a multicolor electrostatic coating device which selectively supplies the colors.

[Prior art and its problems] In this type of multicolor electrostatic coating device, waste of paint during color change is prevented as much as possible, and
It is desirable to shorten the color change cleaning time as much as possible.

In order to meet this requirement, a color changing device for selectively supplying multiple colors of paint is installed near the electrostatic coating machine, and the paint is connected between the electrostatic coating machine and the previous color changing device. It is conceivable to make the supply path short and reduce the amount of paint remaining in the paint supply path.

However, disposing the color changing device in the vicinity of the electrostatic coating machine in this manner is undesirable since it places an excessive load on the reciprocator that drives the electrostatic coating machine according to a predetermined coating pattern.

Therefore, in the past, it was unavoidable to make the paint supply path long, and as a means to shorten the color change cleaning time, high pressure cleaning air and high pressure cleaning thinner were supplied from the color change device to the paint supply path. The interior of the paint supply path and the atomization head of the electrostatic coating machine are cleaned at high speed.

However, with this method, not only is it not possible to eliminate paint waste, but also a large amount of cleaning thinner is supplied into the paint supply path in a short period of time, so a large amount of cleaning thinner can be instantly removed from the atomizing head of the electrostatic sprayer. Paint and cleaning thinner are released and overflow from the waste liquid collection shroud that surrounds the atomizing head of these electrostatic sprayers, scattering outside, and damaging peripheral equipment, the main body of the electrostatic sprayer, etc. There was a problem of contamination.

Furthermore, in order to solve such problems, the following measures have been taken in the past.

That is, there are two
A switching valve having a directional outflow path is installed, and one outflow path of the switching valve is connected to a drainage tank via a drainage on/off valve, and the other outflow path is connected to a drainage tank via a paint hose. When changing colors and cleaning by switching the connection to an electric coating machine, first close the switching valve and at the same time open the drainage on/off valve, and drain the paint through the switching valve. The color change device communicates with the tank, and then alternately supplies high-pressure cleaning air and high-pressure cleaning thinner into the paint supply path from the color change device to discharge the paint remaining in the paint supply path to the drainage tank to clean the inside of the paint supply path. do. Next, the switching valve is opened and the drainage on/off valve is closed at the same time to communicate the cleaned paint supply path with the paint hose containing the remaining paint, and then the color changing device is re-introduced into the paint supply path. The paint remaining in the paint hose is discharged from the atomization head of the electrostatic sprayer by alternately supplying low pressure cleaning air and low pressure cleaning thinner to clean the paint hose and the inside of the atomization head.

However, in this case, the fear of a large amount of paint and thinner being instantly released from the atomizing head and being scattered is eliminated, but high-pressure cleaning air and high-pressure cleaning thinner are first supplied by one color change device. After that,
Since low-pressure cleaning air and low-pressure cleaning thinner are supplied, color change cleaning time cannot be shortened.

[Purpose of the invention]

Therefore, the present invention uses the above-mentioned color changing device as a first color changing device, and separately supplies paints of one or more specific colors that are frequently used, such as white paint and red paint in automobile painting. A second color changing device is disposed near the electrostatic coating machine, thereby cleaning a paint supply path and a paint hose that supply the paint selected by the first color changing device to the electrostatic coating machine. At the same time, the paint supply path is cleaned with high-pressure cleaning air and high-pressure cleaning thinner supplied from a first color changing device, and at the same time, the paint hose is cleaned with low-pressure cleaning air and low-pressure cleaning supplied from a second color changing device. The purpose of the present invention is to provide a color change cleaning method that can significantly shorten the color change cleaning time and prevent paint and thinner from scattering from the atomizing head of an electrostatic coating machine by cleaning with thinner. do.

[Structure of the invention]

To achieve this object, the present invention includes a first color changing device that selectively supplies multiple colors of paint, cleaning air, and cleaning thinner; a second color changing device disposed nearby and selectively supplying at least one color of paint, cleaning air, and cleaning thinner; A first paint supply path for supplying an electrostatic coating machine is connected to a first switching valve having a two-way outlet disposed near the electrostatic coating machine, and one outlet of the switching valve is connected to a first switching valve having a two-way outlet. is connected to a drainage tank via a drainage on/off valve, and the other outlet is connected to the electrostatic paint sprayer via a paint hose, and the paint selected by the second color change device is a second paint supply path for supplying the paint to the electrostatic sprayer is connected to a second switching valve having a two-way outlet interposed between the first switching valve and the paint hose, One outflow path of the switching valve is connected to a drainage tank via a drainage on/off valve, and the other outflow path is connected to the electrostatic coating machine via the paint hose. In the color change cleaning method for an apparatus, when the paint selectively supplied by the first color change device is washed and removed, the paint remaining in the first paint supply path is removed by the first color change device. At the same time, the paint remaining in the paint hose is cleaned by high-pressure cleaning air and high-pressure cleaning thinner supplied from the second color changing device, and low-pressure cleaning air and low-pressure cleaning thinner are supplied from the second color changing device. The atomizing head of the electrostatic atomizer is discharged from the atomizing head of the electrostatic atomizer for cleaning.

[Action of the invention]

According to the present invention, since the second color changing device formed smaller than the first color changing device is disposed near the electrostatic coating machine, the electrostatic coating machine and the second color changing device are arranged in the vicinity of the electrostatic coating machine. The second paint supply path connecting the color changing device can be made very short, and therefore paint waste can be reduced by selectively feeding a frequently used specific color of paint from the second color changing device. It is possible to prevent this and achieve significant savings.

Further, among the first paint supply route and paint hose that supply the paint selected by the first color change device to the electrostatic coating machine, the first paint supply route, which is very long, is connected to the first color change device. At the same time, the short paint hose is cleaned at high speed with high-pressure cleaning air and high-pressure cleaning thinner supplied from the second color changing device. The paint selectively supplied from the replacement device can be washed and removed extremely quickly, and the paint, thinner, etc. do not scatter from the atomization head of the electrostatic coating machine.

〔Example〕

Hereinafter, the present invention will be explained based on specific embodiments shown in the drawings.

FIG. 1 is a system diagram showing a schematic configuration of an electrostatic coating apparatus for automobile coating used in the present invention.

In the figure, 1 is an atomizing head of an electrostatic coating machine to which a high voltage is applied and is driven to rotate at high speed, and 2 is a supply of multiple color paints, cleaning air, and cleaning thinner from multiple paint supply sources (not shown). The first color changing device 3 is formed smaller than the first color changing device 2, and is disposed near the atomizing head 1 of the electrostatic coating machine, and is configured to mix at least one color of paint and a high-temperature paint. Low pressure cleaning air and high pressure cleaning air
A second color change device is supplied with low pressure cleaning thinner.

4 is a relatively long first paint supply path that supplies paint of any color selected by the first color changing device 2 to the atomizing head 1 of the electrostatic coating machine;
The valve is connected to a first switching valve 7 which is disposed near the valve and has two outlet passages 5 and 6.

One outlet 5 of this switching valve 7 is connected to a drain 9 via a drain on/off valve 8 and connected to a drain tank 10, and the other outlet 6 is connected via a short paint hose 11. and is connected to the atomizing head 1.

12 is a very short second paint supply path that supplies the paint selected by the second color change device 3 to the atomization head 1 of the electrostatic coating machine, and is disposed near the atomization head 1. and is connected to a second switching valve 14 having two-way outflow passages 13 and 6.

One outflow path 13 of this switching valve 14 is connected to a drainage path 16 via a drainage on/off valve 15 and connected to the drainage tank 10, and the other outflow path 6 is connected to the first switching valve. It is connected to the atomizing head 1 via a paint hose 11, which is shared with the outflow path 6 of 7.

The first color changing device 2 includes a large number of color changing valves CV1 to CV13 each connected to a paint supply source of a different color.
, low pressure air supply valve LE1, high pressure air supply valve HE1, and high pressure thinner supply valve HS1
and are provided.

The second color change device 3 also includes a frequently used color change valve CVw to which white paint is supplied, a color change valve CVr to which red paint is supplied, a low pressure air supply valve LE2, and a high pressure air supply valve. H.E.
2, a low pressure thinner supply valve LS2, and a high pressure thinner supply valve HS2.

Note that 17 is a shroud that collects the waste liquid discharged from the atomizing head 1.

The above is the general structure of the electrostatic coating apparatus for car painting shown in FIG. 1. Next, the method of the present invention using this apparatus will be specifically explained with reference to the time chart shown in FIG. 2.

For example, white paint and red paint, which are the most commonly used colors for automobile bodies, are applied to the color change valves CVw and CVr of the second color change device 3 disposed near the atomization head 1 of an electrostatic paint sprayer. are supplied respectively,
When a white car is brought to the painting area, a high voltage is first applied to the atomizing head 1 and at the same time it is driven to rotate at high speed.

Then, with the first switching valve 7 closed, the second switching valve 14 is opened, whereby the atomization head is passed from the second color change device 3 to the second paint supply path 12 and the paint hose 11. At the same time, a color change valve CVw disposed in the second color change device 3 is opened to supply white paint to the flow path.

As a result, painting is started, and the white paint is electrostatically atomized and discharged from the atomizing head 1, and the surface of the automobile body being transported is electrostatically coated.

Immediately before the end of painting, the color change valve CVw is closed, and at the same time, the low pressure air supply valve LE2 is opened to air low pressure cleaning air having a pressure similar to that of the white paint supplied from the color change valve CVw. is supplied into the second paint supply path 12.

As a result, the white paint is electrostatically atomized from the atomizing head 1 until the end of painting, and at the same time, it is possible to prevent any unpainted parts from being left on the car body.
Normally, most of the paint remaining in the flow path is electrostatically atomized and released, and is used effectively without waste.

When the painting is completed in this way, the low pressure air supply valve LE2 is closed, and at the same time, the rotation speed of the atomizing head 1 is lowered to open a shroud which is movably arranged near the atomizing head 1. 17 are arranged so as to surround the atomizing head 1. Then, at the same time as closing the second switching valve 14, the drainage on/off valve 15 is opened, and the high pressure air supply valve HE2 and the high pressure thinner supply valve HS2 provided in the second color changing device 3 are alternately switched on and off. The valve is opened to drain the white paint remaining in the second paint supply path 12 to the drain tank 10 through the drain path 16, thereby cleaning the inside of the second paint supply path 12.

Next, at the same time as closing the on-off valve 15, the second switching valve 14 is opened, and then the low pressure air supply valve LE2 and the low pressure thinner supply valve LS2 are alternately opened to start the second paint supply. Atomizing head 1 through channel 12 and paint hose 11
Supply low-pressure cleaning air and low-pressure cleaning thinner inside. As a result, the inside of the paint hose 11 and the atomization head 1
The paint remaining inside is discharged from the atomizing head 1 by low-pressure cleaning air and low-pressure cleaning thinner, and the paint hose 11 and the atomizing head 1 are cleaned.

Therefore, since the paint and thinner are discharged from the atomizing head 1 under low pressure, they are not scattered outside the shroud 17 and contaminate peripheral equipment or the electrostatic coating machine main body. Further, since the second paint supply path 12 and the paint hose 11 through which low-pressure cleaning air and low-pressure cleaning thinner are supplied are very short, the cleaning time can be shortened.

Next, when changing the color from this state to the paint (for example, blue paint) supplied to the color change valve CV1 of the first color change device 2, the second switching valve 14 is closed and, The first switching valve 7 is opened to form a flow path leading from the first color changing device 2 to the atomization head via the first paint supply path 4 and the paint hose 11, and the shroud 17 is atomized. The atomizing head 1 is moved backward to increase the rotational speed of the atomizing head 1 to a predetermined rotational speed.

Next, open the color change valve CV1 and
The blue paint supplied to the CV 1 is supplied to the atomizing head 1 through the flow path to start painting, and the newly transferred automobile body is electrostatically painted.

Then, just before the end of painting, the color change valve CV1
At the same time as closing the low pressure air supply valve LE1
is opened, and low-pressure cleaning air having a pressure comparable to the pressure of the paint supplied from the color change valve CV1 is supplied into the first paint supply path 4.

As a result, the paint in the first paint supply path 4 is continuously supplied to the atomization head 1 and electrostatically atomized until the end of painting, and therefore normally remains in the first paint supply path 4. Most of the paint is electrostatically atomized from the atomizing head 1 and used effectively without waste.

When the coating is completed in this way, the low pressure air supply valve LE1 is closed, the rotational speed of the atomizing head 1 is lowered, and the shroud 17 is placed so as to surround the atomizing head 1.

Then, at the same time as closing the first switching valve 7, the drainage on/off valve 8 is opened, and the high pressure air supply valve HE disposed in the first color changing device 2 is opened.
1 and high-pressure thinner supply valve HS1 are opened alternately to drain the paint remaining in the first paint supply path 4 through the drain path 9 to the drain tank 10,
This cleans the inside of the first paint supply path 4 at high speed. Further, as described above, at the same time as closing the first switching valve 7, the second switching valve 14 is opened, and the low pressure air supply valve LE of the second color changing device 3 is closed.
2 and the low-pressure thinner supply valve LS2 are opened alternately to supply low-pressure cleaning air and low-pressure cleaning thinner into the paint hose 11, thereby cleaning the paint hose 11 and the inside of the atomizing head 1.

Therefore, the inside of the first paint supply path 4, which is formed relatively long, is cleaned at high speed by the high pressure cleaning air and high pressure cleaning thinner supplied from the first color changing device 2, and at the same time, At the same time, the inside of the paint hose 11, which is formed short, is cleaned by the low-pressure cleaning air and low-pressure cleaning thinner supplied from the second color changing device 3, so that the color changing cleaning time is significantly shortened. Furthermore, at this time, since the paint and thinner are discharged from the atomizing head 1 under low pressure, they do not scatter outside the shroud 17 and contaminate peripheral equipment or the electrostatic coating machine main body.

As described above, according to the embodiment, paint of a frequently used specific color is transferred from the second color changing device 3 disposed near the atomizing head 1 of the electrostatic coating machine to a very short second color changer. The paint is supplied to the atomizing head 1 through the paint supply path 12 and the paint hose 11, thereby saving paint.

Also, the first color changing device 2 and the first switching valve 7
A relatively long first paint supply path 4 connected between
and the paint in the second paint supply path 12 connected between the second color change device 3 and the second switching valve 14,
Since low-pressure cleaning air is supplied to the atomizing head 1 immediately before the end of painting, the amount of paint remaining in these first and second paint supply paths 4, 12 at the end of painting is extremely small. This has the effect of reducing the amount of paint that is drained as waste fluid, eliminating waste of paint, and making cleaning easier.

Furthermore, when performing color changing cleaning of the paint supplied from the first color changing device 2, high pressure cleaning air supplied from the first color changing device 2 is passed through the relatively long first paint supply path 4. At the same time, the inside of the paint hose 11 is cleaned with low pressure cleaning air and low pressure cleaning thinner supplied from the second color changing device 3, so the cleaning time is significantly reduced. Can be shortened.

Furthermore, when cleaning the paint hose 11 and the inside of the atomizing head 1, low-pressure cleaning air and low-pressure cleaning thinner are supplied from the second color change device 3, so that the paint remaining in the paint hose 11 and the cleaning are removed. When thinner etc. is discharged from the atomizing head 1, the shroud 17
It will not scatter outside and contaminate peripheral equipment or the electrostatic sprayer itself.

〔Effect of the invention〕

As described above, according to the present invention, when cleaning the paint selected by the first color changing device and supplied to the electrostatic coating machine, the relatively long first paint supply path is At the same time, the interior of the paint hose is cleaned at high speed with high-pressure cleaning air and high-pressure cleaning thinner supplied from a color changing device, and at the same time, the interior of the paint hose is cleaned with low-pressure cleaning air and thinner supplied from a second color changing device installed near the electrostatic sprayer. Since cleaning is performed using low-pressure cleaning thinner, the color change cleaning time can be significantly shortened compared to conventional methods, and the paint and cleaning thinner discharged from the atomizing head of the electrostatic paint sprayer can be removed from the shroud. This has an excellent effect in that it does not scatter to the outside and contaminate peripheral equipment or the electrostatic coating machine itself.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram showing an example of a multicolor electrostatic coating apparatus to which the method of the present invention is applied, and FIG. 2 is a time chart illustrating an example of the method of the present invention. Explanation of the code, 1...Atomization head of electrostatic coating machine, 2...
...First color change device, 3...Second color change device, 4...
...First paint supply path, 7...First switching valve, 8...Drainage on/off valve, 10...Drainage tank, 11...Paint hose, 12...Second paint supply path, 14...Second switching valve, 15
...Drainage on/off valve, CV1~CV13,
CVw, CVr...color change valve, LE1, LE2...low pressure air supply valve, HE1, HE2...high pressure air supply valve, LS2...low pressure thinner supply valve,
HS1, HS2...High pressure thinner supply valve.

Claims (1)

[Claims] 1. A first color changing device that selectively supplies multiple colors of paint, cleaning air, and cleaning thinner, and a first color changing device that selectively supplies multiple colors of paint, cleaning air, and cleaning thinner, and a first color changing device that is smaller than the color changing device and is disposed near the electrostatic coating machine and that has at least one color of paint. , a second color changing device that selectively supplies cleaning air and cleaning thinner, and a first paint that supplies paint of any color selected by the first color changing device to the electrostatic coating machine. 2, wherein the supply path is arranged near the electrostatic coating machine;
connected to a first switching valve having a directional outflow passage, one of the outflow passages of the switching valve being connected to a drain on/off valve;
It is connected to a drainage tank via an off valve, and the other outlet is connected to the electrostatic coating machine via a paint hose, and the paint selected by the second color changing device is transferred to the electrostatic coating machine. A second paint supply path is connected to a second switching valve having a two-way outlet interposed between the first switching valve and the paint hose, so that one of the switching valves A color change cleaning method for a multicolor electrostatic coating device, in which an outflow path is connected to a drainage tank via a drainage on/off valve, and the other outflow path is connected to the electrostatic coating machine via the paint hose. and high-pressure cleaning air that supplies paint remaining in the first paint supply path from the first color change device when cleaning and removing the paint selectively supplied by the first color change device. At the same time, the paint remaining in the paint hose is removed from the electrostatic charge by low-pressure cleaning air and low-pressure cleaning thinner supplied from the second color changing device. A color change cleaning method for a multicolor electrostatic coating device, characterized in that cleaning is performed by discharging water from the atomizing head of the coating machine.