JPH07171451A - Multi-color coating apparatus and color change washing method thereof - Google Patents

Abstract

PURPOSE:To further reduce the cost of a coating material when performing color change washing by reducing the loss of the coating material remaining in a coating material hose to the utmost. CONSTITUTION:In a multi-color coating apparatus in which a coating material of desired color alternatively selected by a color change device 2 provided with a lot of color change valves V1-Vn to which a coating material circulating system 4 for circulating and feeding coating materials of different color is connected and valves Vs, Va to which a washing solvent and washing air are applied is fed to a coater 1 and used for painting, a high pressure washing fluid feeding source 7 for pressure feeding the washing solvent or washing air at pressure higher than the feeding one for the coating material fed by circulation to color change valves V1-Vn is connected to a painting hose 2 for connecting the coater 1 and the color change device 2 on the coater 1 side. A switching valve 8 for switching between a pass leading from the color change device 2 to the coater 1 through the coating material hose 3 and a pass leading from the high pressure washing fluid feeding source 7 to the color change device 2 through the coating material hose 3 is inserted in the connecting part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention supplies a paint of a desired color which is selectively selected by a color changing device equipped with a large number of color changing valves in which each color paint is circulated and applied to a coating machine for coating. Related to multicolor coating equipment.

[0002]

2. Description of the Related Art When coating an object to be coated such as an automobile body which is successively conveyed by a conveyor with a paint of a designated color, a desired color selected by a color changing device 50 is selected as shown in FIG. The regulator 51 is used to supply a fixed amount of the color paint to the coating machine 52. When changing the color from the previous color paint to the next color paint, the cleaning air valve Va and the cleaning solvent valve Vs provided in the color changing device 50 are alternately opened and closed to intermittently supply the cleaning air and the cleaning solvent. By doing so, the previous color paint remaining and adhering in the color changing device 50, the regulator 51, the coating machine 52, and the paint hose 53 connecting them are washed away, and the color mixture of the previous color paint and the next color paint is mixed. Is being prevented.

By the way, in an actual automobile body coating line, the objects to be coated are rarely transported in a group for each coating color, and the objects to be coated which are continuously transported are continuously colored in the same color. In most cases, there is almost no case where coating is performed, and the color is changed at a rate of about 8 to 9 times while the 10 objects are coated. For example, white paint is 50
%, Red paint is 25%, and blue paint is 25%, the same paint color such as white-white-white-white-red-red-blue-blue is conveyed. If the color changes, it is sufficient to change the color twice, from the transition from white to red and from red to blue, but it is extremely rare to be conveyed in this way, and normally white-red-white is used. -Blue-White-Red-
Since they are conveyed in random order such as white-blue, it is necessary to change the color every time an object to be coated arrives.

When the color is changed in this way, cleaning is always performed in order to prevent color mixing, and each time the cleaning is performed, the previous color paint remaining in the paint hose 53 must be discarded. Therefore, not only a huge amount of paint is lost, but also a large amount of cleaning solvent is required to clean the interior of the long paint hose 53, and tens of millions of yen worth of paint and solvent must be discarded in one stage per year. However, there is a problem that the coating cost increases. For this reason, before the completion of coating, the cleaning solvent is fed from the color changing device at a flow rate equal to the coating material supply rate, and the coating material in the coating hose 53 is extruded by the coating solution while coating so that the residual coating material can be used effectively. Has been proposed (Japanese Patent Publication No. 2-37225 and 372).
No. 26).

[0005]

However, when the paint is extruded by the solvent and painted, if the utilization efficiency of the residual paint is approached to 100%, the paint in which a large amount of the solvent is mixed is sprayed in the paint hose 53. Since only 50% of the remaining paint can be used for painting, the paint cost is still low compared to the paint cost for single-color painting that does not require color change cleaning. There was a problem that it was bulky. Therefore, it is a technical object of the present invention to reduce the loss of the paint remaining in the paint hose to the utmost and to further reduce the paint cost, while being able to paint without causing the paint failure.

[0006]

In order to solve this problem, according to the present invention, a large number of color change valves connected to a paint circulation system for circulating each color paint, and a cleaning solvent and cleaning air are supplied. In a multicolor coating device that supplies a paint of a desired color that is selectively selected by a color changing device equipped with a valve to a coating machine, and is higher than the supply pressure of the paint that is circulated and supplied to each of the color changing valves. A high-pressure cleaning fluid supply source that pumps the cleaning solvent or cleaning air by pressure is connected to the painter side of the paint hose that connects the painter and the color changing device, and the connecting part is connected to the paint hose from the color changing device. It is characterized in that a switching valve for switching between a flow path to the coating machine via the flow path and a flow path from the high pressure cleaning fluid supply source to the color changing device via the paint hose is provided.

[0007]

According to the present invention, at the time of coating, when the color change valve of the color change device is opened while the flow path from the color change device to the coating machine is connected via the paint hose, the paint of the desired color can be obtained. Is supplied to the painting machine and painted. And after painting,
By connecting the flow path from the high-pressure cleaning fluid supply source to the color changing device via the paint hose with the switching valve, the paint hose coating machine side is at a pressure higher than the supply pressure of the paint circulated and supplied to the color changing valve. The cleaning solvent or cleaning air is sent from the color changing device side.

Therefore, most of the previous color paint remaining in the paint hose and the color changing device is pushed back to the paint circulating system from the color changing valve, and the paint loss is reduced to the limit. At this time, the paint mixed with the cleaning solvent may be pushed back to the paint circulation system, but since the total amount of paint circulating in the paint circulation system is large, the paint concentration does not change even if the cleaning solvent is mixed a little. Not only that, the cleaning solvent mixed in the paint also supplements the solvent evaporated from the circulating paint tank, and the paint can be used again for painting. Next, the flow path from the color changing device to the coating machine is made to communicate again by the switching valve through the paint hose, and the cleaning solvent and the cleaning air are alternately supplied from the color changing device, and they adhere to the inner wall of the paint hose. If the previous color paint is washed and the next color paint supplied from the color changing device is applied after the washing is completed, no color mixture occurs.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below based on the embodiments shown in the drawings. FIG. 1 is a flow sheet showing a multicolor coating apparatus according to the present invention, FIG. 2 is a time chart showing the opening / closing timing of each valve, FIG. 3 is a flow sheet showing another example, and FIG. 4 is its time chart.

In the figure, reference numeral 1 denotes a coating machine which is connected via a paint hose 3 to a color changing device 2 for selectively feeding a paint of a desired color. The color changing device 2 is supplied with a large number of color changing valves V _{1 to} Vn connected to a paint circulating system 4 including a paint forward pipe 4a and a paint returning pipe 4b for circulating paint for each color paint, and a cleaning solvent. The manifold 5 is provided with a solvent valve Vs for supplying water and an air valve Va for supplying cleaning air.

The paint hose 3 is provided with a regulator 6 for controlling a flow rate for keeping the flow rate of the paint sent from the color changing device 2 constant, and the regulator 6 is provided with the above-mentioned regulator 6. A high-pressure cleaning fluid supply source 7 for supplying a cleaning solvent at a pressure higher than the supply pressure of the paint circulated and supplied to each of the color changing valves V _{1 to} Vn is connected via a switching valve 8.

This switching valve 8 has a flow path from the color changing device 2 to the coating machine 1 via the paint hose 3 and a flow path from the high pressure cleaning fluid supply source 7 to the color changing device 2 via the paint hose 3. The paint is sent from the color changing device 2 to the applicator 1 at the time of coating, and the cleaning solvent sent by pressure from the high-pressure washing fluid supply source 7 resists the supply pressure of the paint at the end of painting. Flow from the paint hose 3 side to the color changing device 2 side, and the residual paint in the paint hose 3 is pushed back toward the color changing device 2. The high-pressure cleaning fluid supply source 7 is not limited to one that pumps only the cleaning solvent, and may alternatively supply the cleaning solvent and the cleaning air, or may supply the cleaning air alone.

The above is an example of the configuration of the present invention.
The operation of will be described with reference to FIG. For example, color changing equipment
Color change valve V for unit 2₁White paint supplied from
Pre-painting the object to be coated After the color painting process is completed, the color changing device
Remain in paint hose 3 from 2 to coating machine 1
Color change washing is performed to wash the paint, and then the color change valve V
₂Subsequent objects to be coated with red paint supplied from
The case of shifting to the color coating process will be described.

First, in the pre-color coating process, the flow path from the color changing device 2 to the coating machine 1 via the paint hose 3 is communicated by the switching valve 8 and the color changing valve V ₁ is opened to open the color changing device 2. The white paint sent from the product flows through the paint hose 3 and is supplied to the coating machine 1 in a fixed amount, and the preceding object is painted white (FIG. 2: T _{1 to} T ₂ ). Then, when the pre-color coating process is completed, next color change cleaning is performed. This color change cleaning, paint remaining in the paint hose 3 paint push-back step to push back the paint circulation system 4 (FIG. 2: T ₃ through T ₄₎ washing and, from the color change device 2 after the paint push-back process is completed It comprises a main cleaning step (FIG. 2: T _{5 to} T ₆ ) of cleaning the inside of the paint hose 3 by alternately supplying the solvent and the cleaning air to the coating machine 1.

In the paint push-back process, the flow path of the switching valve 8 is switched so that the high-pressure cleaning fluid supply source 7 changes to the paint hose 3.
In a state in which the flow path toward the color changing device 2 is connected via
When the color change valve V ₁ of the white paint that has been applied so far is opened again, the cleaning solvent is pressure-fed from the high-pressure cleaning fluid supply source 7 toward the color changing device 2. This solvent supply pressure is higher than the supply pressure of the white paint circulated and supplied to the color change valve V ₁ , so that the washing solvent flows backward from the coating machine 1 side of the paint hose 3 toward the color change device 2 to cause the paint hose. The paint remaining in 3 is pushed back into the paint return pipe 4b.

At this time, the paint mixed with the cleaning solvent may be pushed back to the paint return pipe 4b, but the total amount of paint circulated in the paint circulation system 4 is so large that it cannot be compared with the amount of paint pushed back. Therefore, even if the cleaning solvent is mixed to some extent, not only the paint concentration hardly changes, but also the cleaning solvent mixed in the paint supplements the solvent evaporated from the paint tank interposed in the circulation system 4. The paint can be used again for painting.

Next, in the main cleaning step, the color change valve V ₁ is closed while the flow path of the changeover valve 8 is changed over so that the flow path from the color changer 2 to the coating machine 1 is in communication. When the cleaning air valve Va and the cleaning solvent valve Vs are alternately opened and closed, the cleaning air and the cleaning solvent supplied from the color changing device 2 cause the manifold 5, the regulator 6, the coating machine 1 and the paint hose 3 that connects them. The adhered paint is removed cleanly.

When the color change cleaning is completed in this way, the process proceeds to the next color coating step. In the next color coating step, the color for supplying the red paint is maintained without switching the flow path of the switching valve 8 and the flow path from the color changing device 2 to the coating machine 1 via the paint hose 3 is kept in communication. When the replacement valve V ₂ is opened, the red paint sent from the color changing device 2 is transferred to the paint hose 3
It flows through the inside and is supplied to the coating machine 1 in a fixed amount, and the subsequent object to be coated is painted red (FIG. 2; T ₇ ).

FIG. 3 shows another embodiment. In this embodiment, a gear pump 9 is used as a fixed amount supply means instead of the regulator 6.
A positive displacement metering pump such as the above is interposed in the paint hose 3, and the high pressure cleaning fluid supply source 7 is provided with a cleaning solvent valve 10 and a cleaning air valve 11 for alternately supplying a cleaning solvent and cleaning air. Further, even if the cleaning solvent and the cleaning air are pressure-fed from the high-pressure cleaning fluid supply source 7, it is not possible to reverse the flow in the gear pump 9. Therefore, in this example, the gear pump 9 is avoided in the paint hose 3 to supply the cleaning solvent and the cleaning air. A bypass line 12 capable of flowing is formed, and if necessary, the bypass line 1
An on / off valve 13 for circulating 2 is provided.
Reference numeral 14 is a washing solvent supply pipe line for washing the shaft for leaching the washing solvent from the rotary shaft of the gear of the gear pump 9 to wash the gap between the gear and the casing.

In the case of this example, the pre-color coating process (FIG. 4: T₁~
T₂) Medium and next color coating process (Fig. 4: T₇~)
The valve 13 is closed and the bypass line 12 is shut off.
Therefore, the paint supplied from the color changing device 2 is applied to the gear pump 9
Is supplied to the coating machine 1 in a fixed amount. Also, paint pushback
(Fig. 4: T₃~ T_Four) Medium and main cleaning steps (Fig. 4: T_Five
~ T ₆) Inside, the on-off valve 13 opens and the bypass pipe
The road 12 communicates.

Therefore, in the paint push-back process, the cleaning solvent and the cleaning air alternately supplied from the high-pressure cleaning fluid supply source 7 change colors through the switching valve 8 through the paint hose 3 and the bypass line 12. Backflow toward the device 2 side,
The paint remaining in the paint hose 3 is pushed back into the paint return pipe 4b of the paint circulating system 4. Further, in the main cleaning step, the cleaning air and the cleaning solvent alternately supplied from the color changing device 2 also flow through the bypass conduit 12, so that the interior of the paint hose can be cleaned in a short time. Then, during the main cleaning process, the cleaning solvent is supplied from the cleaning solvent supply pipeline 14 for shaft cleaning to the gear pump 9 to clean the inside of the gear pump 9.

The high-pressure cleaning fluid supply source 7 is not limited to supplying the cleaning solvent and the cleaning air alternately, but may supply the cleaning solvent and the cleaning air independently. Further, the cleaning solvent pressure-fed from the high-pressure cleaning fluid supply source 7 is
Since it mixes with the paint and flows into the paint circulating system 4, it is preferable to use the solvent for diluting the paint as it is. Further, the constant quantity supply means such as the regulator 6 and the gear pump 9 is not limited to the case where the color change device 2 and the coating machine 1 are connected to the paint hose 3 which communicates with each other. It may be the case of wearing.

[0023]

As described above, according to the present invention, after the coating is completed, the switching valve is switched so that the flow path from the high pressure cleaning fluid supply source to the color changing device via the coating hose is communicated. The cleaning solvent or cleaning air is sent from the hose coating machine side to the color changer side at a pressure higher than the paint supply pressure, and most of the paint remaining in the paint hose and color changer is in the paint circulation system. Since it is pushed back to the paint, it is possible to reduce paint loss, and at this time, the paint mixed with the cleaning solvent is also pushed back to the paint circulation system, but the total amount of paint circulating in the paint circulation system is large. Even if a small amount of cleaning solvent is mixed, the paint concentration does not change so much, rather it will supplement the solvent that evaporates from the paint tank that supplies paint to the paint circulation system, and the paint can be used again for painting. Because, there is a very excellent effect that it is possible to reduce the coating cost by reducing paint losses to a minimum.

[Brief description of drawings]

FIG. 1 is a flow sheet of a multicolor coating apparatus according to the present invention.

FIG. 2 is a time chart showing the valve timing.

FIG. 3 is a flow sheet showing another embodiment.

FIG. 4 is a timing chart thereof.

FIG. 5 is a flow sheet showing a conventional multicolor coating device.

[Explanation of symbols]

1 ... Painting machine 2 ... Color changing device 3 ... Paint hose 4 ... Paint circulation system 6 ... Regulator 7 ... High pressure cleaning fluid supply source 8 ... Switching valve 9 ... gear pump 12 ... bypass line V ₁ to Vn ... color changing valve Vs ... cleaning solvent valve Va ... wash air valve

Claims (4)

[Claims] 1. A number of color change valves (V _{1 to} Vn) connected to a paint circulation system (4) for circulating each color paint, and valves (Vs, Va) for supplying cleaning solvent and cleaning air. In the multi-color coating device that supplies the coating device (1) with the paint of a desired color that is selectively selected by the provided color changing device (2), and circulates to each of the color changing valves (V _{1 to} Vn). A high-pressure cleaning fluid supply source (7) for pumping the cleaning solvent or cleaning air at a pressure higher than the supply pressure of the supplied paint is a coating machine (1).
The paint hose (3) that connects the color change device (2) and the paint hose (3) is connected to the painter (1) side, and the connection part is painted from the color change device (2) through the paint hose (3). A switching valve (8) for switching between a flow path toward the machine (1) and a flow path from the high-pressure cleaning fluid supply source (7) through the paint hose (3) to the color changing device (2) is provided. A multicolor coating device characterized by the fact that 2. The paint hose (3) is provided with a regulator (6) for controlling a flow rate, and the switching valve (8) is provided on the side of the coating machine (1) with respect to the regulator (6).
The multicolor coating apparatus according to claim 1, wherein the multicolor coating apparatus is provided. 3. A positive displacement metering pump (9) is provided in the paint hose (3), and the switching valve (8) is provided on the coating machine (1) side of the metering pump (9). The paint hose (3) is equipped with a bypass pipe line (12) for avoiding the metering pump (9) and flowing a cleaning solvent or cleaning air.
The multicolor coating apparatus according to claim 1, wherein the multicolor coating apparatus is formed. 4. A number of color changing valves (V _{1 to} Vn) connected to a paint circulation system (4) for circulating each color paint and valves (Vs, Va) for supplying cleaning solvent and cleaning air. When changing the color of the paint supplied to the coating machine (1) according to the coating color of the object to be coated by the provided color changing device (2), the color changing device (2), the coating machine (1) and these In a color change cleaning method for a multicolor coating device for cleaning the inside of a paint hose (3) to be connected, a cleaning solvent or a cleaning is performed at a pressure higher than the supply pressure of the paint circulatingly supplied to each of the color change valves (V _{1 to} Vn). The high-pressure cleaning fluid supply source (7) for pumping air is a switching valve (8).
Via the paint hose (3) to the coating machine (1) side, and (a) after finishing the coating, the switching valve (8) from the high pressure cleaning fluid supply source (7) via the paint hose (3). The flow paths to the color changing device (2) are communicated with each other, and the respective color changing valves (V _{1 to} Vn) are directed from the coating machine (1) side of the paint hose (3) to the color changing device (2) side. A paint push-back step of feeding a cleaning solvent or cleaning air at a pressure higher than the supply pressure of the paint circulatingly supplied to the paint and pushing back the paint remaining in the paint hose (3) to the paint circulation system (4); ) The switching valve (8) connects the flow path from the color changing device (2) to the coating machine (1) via the paint hose (3) so that the cleaning solvent and the cleaning air can flow from the color changing device (2). A main washing step of feeding the paint to the coating machine (1) and washing the inside of the paint hose (3). A method for changing color of a multicolor coating device, characterized by: