JP3208065B2 - Rotary atomizing head type coating equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary atomizing head type coating apparatus suitable for coating, for example, an automobile body.

[0002]

2. Description of the Related Art A conventional rotary atomizing head type coating apparatus will be described with reference to FIG.

[0003] In the drawing, reference numeral 1 denotes an electrostatic coating machine having a rotary atomizing head 1A. In the coating machine 1, a tip side extends into the rotary atomizing head 1A. A bundled feed tube 2 is provided. Then, the coating machine 1 rotationally drives the rotary atomizing head 1A by an air drive source (not shown) provided in the coating machine 1, and feeds the feed tube 2 of the bundle-shaped feed tube 2.
The paint of each color supplied from A, 2B, 2C, 2D, and 2E is sprayed by centrifugal force, and the paint is applied to the object to be coated by using an attraction force caused by an electrostatic field between the coating machine 1 and the object to be coated. Apply. One of the bundle-shaped feed tubes 2 is a thinner supply feed tube 2T to which a thinner for cleaning the rotary atomizing head 1A is supplied at the time of color change or the like.

[0004] 3A, 3B, 3C, 3D, 3E are paint sources. The paint sources 3A to 3E are, for example, A color, B color, C color.
It is a circulation that supplies five colors of paints of color, D color and E color. The paint sources 3A to 3E are connected to paint pumps 5A to 5E to be described later via paint supply valves 4A, 4B, 4C, 4D, and 4E. And paint supply valve 4
By opening the valves A to 4E and driving the paint pumps 5A to 5E, each color paint from the paint sources 3A to 3E is applied to the coating machine 1.
Supplied to the side.

[0005] 5A, 5B, 5C, 5D and 5E are paint sources 3
A paint pump which discharges each color paint supplied from A to 3E toward the coating machine 1 is shown, and the paint pumps 5A to 5E are shown.
Are connected to the drive motor 6 by clutches 7A, 7B, 7C, 7D,
7E. For example, paint pump 5A
Is driven by driving the drive motor 6 and the clutch 7A
Concatenate. In order to stop the paint pump 5A and drive the paint pump 5B, the clutch 7A is released and the clutch 7B is connected with the drive motor 6 being driven. In this manner, by operating the connection and disconnection of the clutches 7A to 7E, the paint pump 5 is driven by the single drive motor 6.
Driving and stopping of A to 5E can be controlled.

Reference numerals 8A, 8B, 8C, 8D and 8E denote paint passages for supplying paints of the respective colors to the coating machine 1 side.
A to 8E are connected to the paint sources 3A to 3E via paint pumps 5A to 5E and paint supply valves 4A to 4E on the base end side, and connected to the feed tubes 2A to 2E of the bundle feed tube 2 of the coating machine 1 on the distal end side. Have been. Also, paint passage 8A
-8E, a portion between the paint pumps 5A-5E and paint valves 11A-11E, which will be described later, corresponds to the paint source side paint passages 9A and 9E.
B, 9C, 9D, and 9E, and the distance from the paint valves 11A to 11E to the coating machine 1 is a coating machine side paint passage 10A, 10E.
B, 10C, 10D, and 10E.

[0007] 11A, 11B, 11C, 11D, 11E
Denotes paint valves provided between the coating machine 1 and the paint pumps 5A to 5E and in the middle of the paint passages 8A to 8E. The paint valves 11A to 11E are constituted by two-port two-position switching valves. I have. The paint valves 11A to 11E are always closed to shut off the paint source side paint passages 9A to 9E and the coating machine side paint passages 10A to 10E. The paint valves 11A to 11E are opened when the paint is supplied to the coating machine 1, and the paint valves 9A to 9E communicate with the paint passages 10A to 10E.

Reference numeral 12 denotes a washing passage whose leading end is connected to the thinner supply feed tube 2T of the bundle-shaped feed tube 2. The washing passage 12 has a base end connected to a washing thinner source 13. Reference numeral 14 denotes a coating machine cleaning valve provided in the middle of the cleaning passage 12, and the coating machine cleaning valve 14 is a 2-port 2-position switching valve. The coating machine washing valve 14 is normally closed to shut off the washing passage 12. The coating machine cleaning valve 14 is opened when the rotary atomizing head 1A of the coating machine 1 is cleaned at the time of color change, the cleaning passage 12 is connected, and the thinner from the cleaning thinner source 13 is supplied to the coating machine 1. It is supplied to the rotary atomizing head 1A.

Here, when the paint is supplied to the feed tubes 2A to 2E at the preparatory stage before painting or at the time of painting, the paint flows out of the feed tubes 2A to 2E. The paint adheres.
At this time, a paint pool is formed at the distal ends of the feed tubes 2A to 2E, and a part of the paint pool is formed.
E Adhere to the outer surface of the tip. Therefore, feed tube 2A
After the paint is supplied to ２2E or at the time of color change during the painting operation, the coating machine washing valve 14 is opened to supply the thinner to the rotary atomizing head 1A side. The paint adhering to the outer surfaces of the tips of the tubes 2A to 2E is washed away.

Reference numeral 15 denotes the paint passages 8A to 8 after the end of painting.
E, paint pumps 5A to 5E, feed tubes 2A to 2
E shows a cleaning valve device for cleaning the rotary atomizing head 1A and the like, and the cleaning valve device includes cleaning gate valves 16A, 16B and 16;
C, 16D, and 16E are connected to the suction sides of the paint pumps 5A to 5E. The cleaning valve device 15 includes a thinner valve 17 and an air valve 18.
7 is connected to a thinner source 19, and the air valve 18 is connected to an air source 20.
It is connected to the.

Here, the paint passages 8A to 8A
E, paint pumps 5A to 5E, feed tubes 2A to 2
E, when cleaning the rotary atomizing head 1A, etc., the cleaning gate valves 16A-1A with the paint supply valves 4A-4E closed.
6E and the paint valves 11A to 11E are opened to open the paint pump 5A.
To 5E. Then, the thinner valve 17 and the air valve 18 of the cleaning valve device 15 are alternately opened and closed at predetermined time intervals, whereby the thinner and the air are alternately supplied to the paint passages 8A to 8E. As a result, the paint adhered to the paint passages 8A to 8E, the paint pumps 5A to 5E, the feed tubes 2A to 2E, the rotary atomizing head 1A and the like are washed away.

Reference numeral 21 denotes a suction passage, which connects between a thinner source 22 for filling and a waste liquid tank 23. Further, a thinner filling valve 24 located on the side of the filling thinner source 22 and a discharge valve 25 located on the side of the waste liquid tank 23 are provided in the middle of the suction passage 21. Each of the thinner filling valve 24 and the discharge valve 25 is constituted by a 2-port 2-position switching valve. Further, both the thinner filling valve 24 and the discharge valve 25 are normally closed to shut off the suction passage 21 at each position, and connect the suction passage 21 when the valve is opened. Further, a suction pump 26 is disposed in the suction passage 21 between the thinner filling valve 24 and the discharge valve 25. Here, the suction pump 26 is connected to the drive motor 6 via the clutch 27 together with the paint pumps 5A to 5E. The suction pump 26 drives the drive motor 6 and connects the clutch 27. Drive.

A thinner filling valve 24 and a suction pump 26
The base end sides of the suction branch passages 28A, 28B, 28C, 28D, and 28E are connected to a connection point A in the middle of the suction passage 21 and the distal ends of the suction branch passages 28A to 28E will be described later. They are connected to the suction gate valves 29A to 29E, respectively. The suction branch passages 28A to 28E
Is used to suck a small amount of paint toward the waste liquid tank 23 in order to prevent the paint from dripping from the tips of the feed tubes 2A to 2E, as described later. It is formed by a small diameter tube.

29A, 29B, 29C, 29D, 29E
Indicates a suction gate valve, and the suction gate valves 29A to 29E
Is constituted by a 2-port 2-position switching valve. The suction gate valves 29A to 29E are always closed, and the painter side paint passages 10A to 10E and the suction branch passages 28A to 28E are closed.
28E. The suction gate valves 29A to 29E are opened when a small amount of paint is sucked from the feed tubes 2A to 2E of the coating machine 1 at the time of color change, and the paint machine side paint passages 10A to 10E and the suction branch passages 28A to 28E. And communicate with each other.

A rotary atomizing head type coating apparatus according to the prior art has the above-described configuration. Next, this operation will be described.

First, in the preparation stage before painting, the suction passage 2
1 and the suction branch passages 28A to 28E are filled with a thinner for filling. That is, the suction gate valves 29A to 29E are closed, and the coating machine side paint passages 10A to 10E and the suction branch passages 28A to 28E are closed.
In a state in which the suction pump 26 is shut off, the suction pump 26 is operated by opening the thinner filling valve 24 and the discharge valve 25. Thus, thinner is supplied from the filling thinner source 22 to the suction passage 21, and the thinner flows toward the waste liquid tank 23. The thinner supplied to the suction passage 21 is also supplied to the suction branch passages 28A to 28E. Thus, the suction passage 21 and the suction branch passages 28A to 28E are filled with thinner.

Then, the paint supply valves 4A to 4E and the paint valves 11A to 11E are opened, the paint pumps 5A to 5E are operated, and the paint passages 8A to 8E and the feed tubes 2A to 2E are opened.
Fill each color paint in 2E. After the filling of each color paint is completed, the paint pumps 5A to 5E are stopped and the paint supply valve 4A is stopped.
4E and the paint valves 11A to 11E are closed.

Thereafter, a small amount of paint is sequentially sucked from the feed tubes 2A to 2E. First, the suction gate valve 29A
Is opened, the coating machine side paint passage 10A and the suction branch passage 28 are opened.
Connect A. Then, the discharge valve 25 is opened, the suction pump 26 is operated, and the feed tube 2A is opened.
Suction a small amount of paint from. Further, a small amount of paint is similarly sucked from the feed tubes 2B to 2E. Thus, by sucking a small amount of paint from the feed tubes 2A to 2E, each color paint staying in the feed tubes 2A to 2E is prevented from dripping from the tip of the feed tubes 2A to 2E.

Thereafter, the coating machine cleaning valve 14 is opened, and the cleaning thinner discharged from the cleaning thinner source 13 flows into the thinner supply feed tube 2T of the coating machine 1, and the rotary atomizing head 1A, the feed tube 2A to 2E Wash off the paint adhering to the outer surface of the tip.

On the other hand, at the time of painting, for example, when painting with the A color paint, the paint supply valve 4A for A color and the paint valve 11A are opened with the suction gate valves 29A to 29E closed, and the paint is applied. The pump 5A is operated. Thus, the A-color paint is supplied from the paint source 3A to the feed tube 2A of the coating machine 1 via the paint passage 8A, and the A-color paint is performed. The same applies to the colors B to E.

When the color is changed, for example, when the color is changed from the color A paint to the color B paint, the paint pump 5A for A color is stopped, the paint supply valve 4A and the paint valve 11A are closed, and then the suction gate is changed. The valve 29A is opened to allow the painter side paint passage 10A to communicate with the suction branch passage 28A. And the discharge valve 25
And the suction pump 26 is operated. Thus, the filling thinner filled in the suction passage 21 and the suction branch passage 28A is sucked, and at the same time, a small amount of the A-color paint filled in the coating machine-side paint passage 10A is sucked.
As a result, a small amount of the A color paint is sucked from the A color feed tube 2A of the coating machine 1, and the feed tube 2A
Has a slight cavity at the tip. In this way, the A-color paint staying in the feed tube 2A during the coating of each color is prevented from dripping from the tip of the feed tube 2A.

As described above, thinner is filled in the suction passage 21 and the suction branch passages 28A to 28E in the preparation stage before coating, and the feed tube 2A of the coating machine 1 is used at the time of color change during coating or the like. By sucking a small amount of paint from ２2E, paint dripping of the coating machine 1 is prevented, and the occurrence of coating defects and the like is prevented.

After the suction operation has been completed, the coating machine cleaning valve 14 is opened, whereby the cleaning thinner source 1 is opened.
The cleaning thinner discharged from 3 is supplied to the thinner supply feed tube 2T of the coating machine 1 to wash away the A-color paint adhered to the outer surfaces of the rotary atomizing head 1A and the feed tubes 2A to 2E. Further, in order to continue coating with the B color paint, the paint supply valve 4B and the paint valve 11B for B color are opened, and the paint pump 5B is operated.

[0024]

In the above-mentioned prior art, the suction branch passage 28 is connected to the connection point A of the suction passage 21.
A to 28E are connected, and suction gate valves 29A to 29E are connected to the distal ends of the suction branch passages 28A to 28E. In such a configuration, at the preparation stage before painting, when filling the suction passage 21 and the suction branch passages 28A to 28E with the filling thinner, the suction branch passages 28A to 28E are used.
There is a problem that an air pool is generated in E and the air pool remains in the suction branch passages 28A to 28E.

That is, the suction passage 21 and the suction branch passage 28A
When filling the filling thinner into the filling thinner, the suction gate valves 29A to 29E are closed and the paint passage 10A on the coating machine side is closed.
Between the suction branch passages 28A to 28E and the suction branch passages 28A to 28E. Accordingly, the distal ends of the suction branch passages 28A to 28E are dead ends at the suction gate valves 29A to 29E, and the suction branch passages 28A to 28E are closed portions in the form of dead ends. For this reason, the filling thinner supplied from the filling thinner source 22 is less likely to flow into the suction branch passages 28A to 28E,
The filling thinner may not be sufficiently filled up to the distal end side of the suction branch passages 28A to 28E. As a result, air accumulation may occur in the suction branch passages 28A to 28E, and the air may remain in the suction branch passages 28A to 28E.

The air in the suction branch passages 28A to 28E is filled by opening the suction gate valves 29A to 29E and connecting the suction branch passages 28A to 28E to the coating machine side paint passages 10A to 10E. It is possible to use the discharge force of the thinner source 22 to push the thinner source 22 toward the coating machine 1. However, in this case, there is a disadvantage that the fee for using the thinner for filling increases. In addition, during the painting operation, the paint passages 10A to 10E are filled with the paint of each color, so that there is a drawback that such air cannot be pushed out.

Furthermore, if air accumulation occurs in the suction branch passages 28A to 28E, it becomes difficult to adjust the suction amount of the paint when sucking a small amount of paint from the feed tubes 2A to 2E of the coating machine at the time of color change. The problem arises. That is, the suction of the paint at the time of the color change may be such that a slight cavity is formed at the tip side of the feed tubes 2A to 2E in order to prevent the paint from dripping. However, when an air pool is generated in the suction branch passages 28A to 28E, the air generated by the air pool separates the paint in the coating machine side paint passages 10A to 10E from the thinner in the suction branch passages 28A to 28E. As a result, the paint and the thinner are in a liquid discontinuous state. As a result, the suction force of the suction pump 26 is not accurately transmitted to the feed tubes 2A to 2E, so that the paint may not be sucked from the inside of the feed tubes 2A to 2E, and the paint may drool and a coating failure may occur. There is a problem.

On the other hand, at the time of color change, the suction gate valves 29A to 29A.
A small amount of paint flows into the suction branch passages 28A to 28E and the suction passage 21 via the suction branch passages 29A to 29E.
28E, adheres inside the suction passage 21. In particular, since the suction branch passages 28A to 28E are small-diameter tubes having a diameter of about 2 to 5 mm, if the paint adheres to the inner surfaces of the suction branch passages 28A to 28E, the flow passage area in the pipe becomes small, and the pressure loss in the pipe changes. . As a result, the amount of paint suction changes,
Paint cannot be sucked accurately.

Therefore, conventionally, the insides of the suction branch passages 28A to 28E and the suction passage 21 are periodically cleaned by the following means.

In the first means, first, a thinner source 2 for filling is used.
2, thinner filling valve 24, connection point A, suction pump 26,
The thinner for filling is supplied to the waste liquid tank 23 through the discharge valve 25 to clean these passages. Next, thinner source 2 for filling
2 to thinner filling valve 24, connection point A, suction branch passage 28
A to 28E, the thinner for filling is flown to the coating machine 1 side through the coating machine side paint passages 10A to 10E to wash these passages.

In the second means, the thinner for filling is simultaneously passed through the above-mentioned passage from the thinner source for filling 22 to the waste liquid tank 23 and the above-mentioned passage from the thinner source for filling 22 to the coating machine 1. Wash at the same time.

However, in each of the conventional cleaning means described above,
Since the lengths of the passages through which the filling thinner flows are different, there is a problem that a large amount of the filling thinner must be used in order to spread the filling thinner throughout each passage.

When the suction gate valves 29A to 29E are closed, the leading ends of the suction branch passages 28A to 28E are dead ends. In this state, it is difficult to flow the filling thinner to the distal ends of the suction branch passages 28A to 28E, and the distal ends of the suction branch passages 28A to 28E cannot be reliably washed. Therefore, in the above-described conventional cleaning means, the suction gate valves 29A to 29E are opened to clean the distal ends of the suction branch passages 28A to 28E, and the suction branch passages 28A to 28E and the coating machine side paint passage 10A are cleaned. -10
E, and the filling thinner is supplied from the filling thinner source 22 to the suction branch passages 28A to 28E and the coating machine side paint passage 1
0A to 10E are circulated and flow toward the coating machine 1 side. For this reason, the coating machine side paint passages 10A to 10A
The paint in E is discarded and blown, so that not only the amount of thinner for filling becomes large, but also the paint passage 10A to the paint machine side.
There is a problem that the paint in 10E must be discarded unnecessarily, and the operation becomes complicated.

The present invention has been made in view of the above-mentioned problems of the prior art, and the present invention has been made in consideration of the above-mentioned problems in the prior art. It is an object of the present invention to provide a rotary atomizing head type coating apparatus capable of surely and accurately sucking a small amount of paint from a tube.

It is another object of the present invention to provide a rotary atomizing head type coating apparatus capable of efficiently cleaning the suction passage and reducing the amount of solvent used.

[0036]

In order to solve the above-mentioned problems, a rotary atomizing head type coating apparatus according to the present invention comprises: a coating machine having a rotary atomizing head; a rotary atomizing head provided in the coating machine; A plurality of feed tubes extending into the head, a plurality of paint passages having a base end connected to each color paint source and a distal end connected to each feed tube, and a middle of each paint passage. Which communicates between the paint source paint passage on the inflow side and the coating machine paint passage on the outflow side,
It adopts a configuration consisting of a paint valve that shuts off.

A feature of the invention described in claim 1 is that a suction passage having a base end connected to a solvent source and a front end connected to a waste liquid tank is provided in the suction passage corresponding to each of the paint valves. A plurality of suction gate valves are provided to communicate with and shut off the paint passages on each coating machine side, respectively, to a waste liquid tank, and to communicate and shut off between a solvent source and a waste liquid tank, and to a solvent inflow side of each suction gate valve. A solvent filling valve connected to and provided with a solvent from a solvent source to fill a suction passage; and a suction filling valve provided in the middle of the suction passage at a position closer to the waste liquid tank than each of the suction gate valves. A suction pump that operates when filling the suction passage with a solvent or sucking a small amount of paint from each of the feed tubes.

According to the above configuration, first, in a preparation stage before coating, each suction gate valve and a suction passage are filled with a solvent. That is, each suction gate valve shuts off the space between each coating machine side paint passage and the waste liquid tank, and connects the solvent source to the waste liquid tank. Then, the solvent filling valve is opened, and the suction pump is driven. As a result, the solvent discharged from the solvent source flows through the suction gate and the suction passage toward the waste liquid tank, and the suction gate and the suction passage are filled with the solvent.

Here, the space between the solvent source and the waste liquid tank is connected by one suction passage, and each suction gate valve and the suction pump are arranged in the middle of the suction passage. The space up to the tank is continuously connected by a suction passage, and there is no dead end-shaped closed portion having a dead end on the way. Thus, at the time of filling the solvent, the solvent flows in one direction from the solvent source toward the waste liquid tank, and the solvent completely reaches the suction passage. Therefore, no air accumulation occurs in the suction passage.

Next, at the time of coating, one of the paint valves corresponding to a desired color is operated to connect the paint source side paint passage and the coating machine side paint passage. As a result, the one-color paint supplied from the paint source is fed into the feed tube of the painting machine, and painting is performed. At this time, each suction gate valve shuts off between the paint passage on the coating machine side and the waste liquid tank and communicates the solvent source with the waste liquid tank, similarly to the above-described pre-coating preparation stage. The valve and the suction passage are filled with the solvent.

Next, at the time of color change, the supply of the previous color paint is stopped by stopping the drive of the paint source, and the one paint valve shuts off the paint source side paint passage and the paint register side paint passage. I do. Then, the suction gate valve corresponding to the one paint valve is operated to connect the paint passage on the coating machine side with the waste liquid tank, and at the same time, shuts off between the solvent source and the waste liquid tank, and drives the suction pump. After a lapse of a short time, the suction gate valve shuts off the paint passage between each coating machine and the waste liquid tank, and stops the suction pump. As a result, a small amount of paint is sucked from the feed tube of the front color, and the paint at the discharge end of the feed tube is pulled up to the base end of the feed tube of the front color by a small amount.

Here, since the space between the solvent source and the waste liquid tank is connected by a suction passage having no closed path in the form of a blind alley, the suction passage is completely filled with the solvent in a preparation stage before coating. And there is no air accumulation.
Thus, the paint in the painter-side paint passage and the solvent in the suction passage are continuously brought into contact with each other by connecting the painter-side paint passage and the waste liquid tank by the suction gate valve during color change. That is, air does not intervene between the paint and the solvent unlike the prior art. Therefore, when the suction pump is driven, the suction force of the suction pump is reliably transmitted to the tip of the feed tube through the solvent in the suction passage and the paint in the painter-side paint passage. Therefore, the paint in the feed tube is accurately sucked by a predetermined small amount.

On the other hand, as described above, at the time of color change, a small amount of paint is sucked from the feed tube into the suction passage, so that the paint may adhere to the suction passage. When the paint adhered in the suction passage is washed, the suction gate valve shuts off the paint passages on each coating machine side and the waste liquid tank, and connects the solvent source to the waste liquid tank. Then, the solvent filling valve is opened, and the suction pump is driven. As a result, the solvent discharged from the solvent source flows through the suction passage toward the waste liquid tank, so that the paint adhered to the suction passage is washed away by the solvent.

At this time, since there is no closed path in the suction passage, the solvent flows from the solvent source to the waste liquid tank, and the solvent flows to all locations in the suction passage. That is, the solvent does not stay in a part of the suction passage, and there is no place where the solvent does not reach. Therefore, it is possible to efficiently clean the inside of the suction passage with a small amount of solvent.

Further, the suction passage can be washed while the paint passage on the side of each coating machine and the waste liquid tank are shut off by the suction gate valve. Therefore, when cleaning the suction passage as in the prior art, it is not necessary to supply the thinner to the paint passage on the painting machine side and discard the paint filled in the paint passage on the painting machine side. That is, it is not necessary to throw away the paint.

According to a second aspect of the present invention, each suction gate valve includes a suction port connected to the paint passage on the coating machine side, an inflow port connected to the outflow side of the solvent filling valve, and an inflow side of the suction pump. A suction port connected to the suction gate valve and a suction port when the suction passage is filled with the solvent, and a suction port and a discharge port when sucking a small amount of paint from each feed tube. That is, a three-port switching valve for communicating with a port is provided.

According to the above configuration, when filling the suction gate valve and the suction passage with the solvent, each suction gate valve is operated to connect the inflow port and the discharge port, and to shut off the connection between the suction port and the discharge port. I do. Then, by opening the solvent filling valve and driving the suction pump, the solvent flows from the solvent source to the waste liquid tank through the suction passage. At this time, since the path from the solvent source to the waste liquid tank is continuously connected by the suction passage, and there is no dead end-shaped blockage having a dead end in the middle, each suction gate valve and the suction passage are reliably filled with the solvent. As a result, no air accumulation occurs.

At the time of color change, each suction gate valve is operated to connect the suction port and the discharge port and to shut off the connection between the suction port and the discharge port. Then, the suction pump is driven to suck a small amount of the paint from inside the feed tube. At this time, the solvent is sufficiently filled in each suction gate valve and the suction passage, and no air pool is generated in the suction passage, so that a predetermined small amount of paint in the feed tube is accurately sucked.

According to a third aspect of the present invention, each suction gate valve is provided in parallel with the suction passage. Thus, when filling each suction gate valve and the suction passage with the solvent, the solvent is uniformly and surely filled into each suction gate valve, and no air pool is generated in the suction passage. The paint in the passage and the solvent in the suction passage can be continuously brought into contact with each other.

The invention described in claim 4 is that an air source is provided together with a solvent source on the inflow side of the solvent filling valve.
This makes it possible to clean the suction gate valves and the suction passages. That is, each suction gate valve is operated to shut off the space between each coating machine side paint passage and the waste liquid tank, and to connect the solvent source to the waste liquid tank. Then, the solvent filling valve is opened, and the suction pump is driven. In this state, by alternately supplying the solvent and the air from the solvent source and the air source to the suction passage, the paint adhered to each suction gate and the suction passage can be washed away.

[0051]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

Here, FIGS. 1 to 5 show a rotary atomizing head type coating apparatus according to an embodiment of the present invention. In this embodiment, the same components as those of the above-described prior art are denoted by the same reference numerals, and description thereof will be omitted.

In the drawing, reference numeral 31 denotes a suction passage according to the present embodiment. The suction passage 31 has a base end side passage 31A connected to a thinner source 38 and an air source 39 to be described later, and a front end side passage 31B connected to a waste liquid tank 41. It is connected to the. The suction passage 31 includes a proximal passage 31A and a distal passage 31B.
, And branches in parallel into five passages, and suction gate valves 34A to 34E described later are provided in the middle of each of the branch passages. Further, the suction passage 31 is connected to the suction gate valve 3.
4A-34E are thinner source side suction passages 32A, 3A.
2B, 32C, 32D, 32E, and the suction gate valve 3
The outflow sides of 4A to 34E are the waste liquid tank side suction passages 33A,
33B, 33C, 33D, and 33E.

34A, 34B, 34C, 34D, 34E
Denotes suction gate valves provided in parallel with the paint valves 11A to 11E, and the suction gate valves 34A to 34E
As shown in FIG. 2, it is a three-port two-position switching valve (three-way valve) having a suction port a, an inflow port b, and a discharge port c. The suction ports a of the suction gate valves 34A to 34E are connected to the paint passages 10A to 10E. The inflow ports b of the suction gate valves 34A to 34E are connected to thinner source side suction passages 32A to 32E. Further, the discharge ports c of the suction gate valves 34A to 34E are connected to the waste liquid tank side suction passages 33A to 33E.

The suction gate valves 34A to 34E
Is normally in the switching position (a) by the return spring, and connects the thinner source side suction passages 32A to 32E with the waste liquid tank side suction passages 33A to 33E, and also paint device side paint passages 10A to 10E and the waste liquid tank side. Suction passage 3
It blocks between 3A-33E. The suction gate valves 34A to 34E shut off the thinner source side suction passages 32A to 32E and the waste liquid tank side suction passages 33A to 33E when the switching position (B) is attained. 10A to 10E and the waste liquid tank side suction passage 33
A to 33E are communicated.

Reference numeral 35 denotes a suction passage cleaning valve device provided on the inflow side of the suction passage 31.
Is constituted by a thinner valve 36 and an air valve 37.
The thinner valve 36 has a thinner source 3 as a solvent source.
8 is connected, and the air source 39 is connected to the air valve 37 with the thinner source 3.
8 are connected in parallel.

The thinner valve 36 is normally closed to shut off the space between the thinner source 38 and the suction passage 31. When the thinner is filled in the suction passage 31 or the like, or when the suction passage 31 or the like is filled. When cleaning the valve, open the thinner source 38
And the suction passage 31 are communicated. Thus, thinner as a solvent is supplied from the thinner source 38 toward the suction passage 31.

The air valve 37 is normally closed.
Although the air path between the air source 39 and the suction passage 31 is shut off, the valve is opened when the suction passage 31 and the like are washed, and the air source 39 and the suction passage 31 are communicated. That is, as described later, when cleaning the suction passage 31 and the like, the thinner valve 36 and the air valve 37 are alternately opened and closed at predetermined time intervals, and the suction passage 3 is cleaned.
1 is supplied with thinner and air alternately.

Reference numeral 40 denotes a thinner filling valve as a solvent filling valve provided on the outlet side of the thinner valve 36 and the air valve 37.
As shown in FIG. 2, the thinner filling valve 40 normally closes to shut off the suction passage 31 on the inflow side. However, when filling the suction passage 31 or the like with thinner as a solvent, or The valve is opened when the passage 31 and the like are washed, and the suction passage 3
Let 1 communicate.

Reference numeral 41 denotes a waste liquid tank provided on the outflow side of the suction passage 31 according to the present embodiment. The waste liquid tank 41 is a tank for storing the thinner discharged from the suction passage 31. Reference numeral 42 denotes a discharge valve provided on the outflow side of the suction passage 31 according to the present embodiment. As shown in FIG. 2, the discharge valve 42 is normally closed to shut off the suction passage 31 on the outflow side. However, when filling the suction passage 31 or the like with thinner,
When a small amount of paint is sucked from the feed tubes 2A to 2E, or when the suction passage 31 or the like is to be washed, the valve is opened and the suction passage 31 is connected.

Reference numeral 43 denotes a suction pump provided on the inflow side of the discharge valve 41. The suction pump 43 is a suction gate valve 3
When filling thinner into the suction passages 4A to 34E and
The operation is performed when a small amount of paint is sucked from the feed tubes 2A to 2E or when the suction passage 31 or the like is washed. Further, the suction pump 43 is connected to the drive motor 6 via the clutch 44 together with the paint pumps 5A to 5E. The suction pump 43 is driven by driving the drive motor 6 and connecting the clutch 44. I do.

The rotary atomizing head type coating apparatus according to the present embodiment has the above-described configuration. Next, this operation will be described.

First, the operation of the rotary atomizing head type coating apparatus in the preparation stage before coating will be described with reference to the time chart shown in FIG. First, suction gate valves 34A-3A
4E and the suction passage 31 are filled with a thinner for filling. That is, with the suction gate valves 34A to 34E at the switching position (A) in FIG.
6. The thinner filling valve 40 and the discharge valve 42 are opened, and the suction pump 43 is operated. As a result, the thinner discharged from the thinner source 38 becomes thinner source-side suction passages 32A to 32A.
E flows through the waste liquid tank side suction passages 33A to 33E through the suction gate valves 34A to 34E, and flows toward the waste liquid tank 41. Thereafter, the suction pump 43 is stopped, and the discharge valve 42, the thinner filling valve 40, and the thinner valve 36 are closed. Thus, the suction gate valves 34A-34
E. The suction passage 31 is filled with thinner.

Here, the suction passage 31 is a passage that continuously connects the thinner source 38 to the waste liquid tank 41, and the suction passage 31 does not have a dead end-shaped closed portion having a dead end in the middle. Thus, at the time of filling the thinner, the thinner discharged from the thinner source 38 flows in one direction toward the waste liquid tank 41, and the thinner completely reaches all corners in the suction passage 31. Therefore, the thinner can be reliably filled in the suction passage 31, and the occurrence of air accumulation in the suction passage 31 can be prevented.

Next, each color paint is filled into the paint passages 8A to 8E and the feed tubes 2A to 2E. That is, the paint supply valves 4A to 4E and the paint valves 11A to 11E are opened,
The paint pumps 5A to 5E are operated. Thereby, each color paint is supplied from the paint sources 3A to 3E, and the paint passages 8A to 8E are supplied.
8E and the inside of the feed tubes 2A to 2E. Thereafter, the paint pumps 5A to 5E are stopped, and the paint supply valves 4A to 4E are stopped.
4E and the paint valves 11A to 11E are closed. Thus, the paint passages 8A to 8E and the feed tubes 2A to
Each color paint is filled in 2E. The filling of each color paint may be performed sequentially for each color, or may be performed simultaneously for all colors.

Next, a small amount of paint is sucked from the feed tubes 2A to 2E. That is, first, the suction gate valve 34A for the A color is set to the switching position (b) in FIG. 2, and the paint passage 10A and the waste tank suction passage 33A are communicated. Then, the discharge valve 42 is opened, and the suction pump 43 is operated. As a result, a small amount of the thinner for filling filled in the waste liquid tank side suction passage 33A is sucked, and a small amount of the A color paint filled in the coating machine side paint passage 10A is sucked. As a result, a small amount of the A color paint is sucked from the A color feed tube 2A, and a slight cavity is formed at the tip of the feed tube 2A. This prevents the A color paint from dripping from the tip of the feed tube 2A.

Since the object is achieved only by sucking a small amount of paint from the feed tube 2A, the suction gate valve 34A is switched to the switching position (B) and then returned to the switching position (A) in a short time. Along with this, the suction pump 43 also stops, and the discharge valve 42 also closes. Further, a small amount of paint is sucked from the feed tubes 2B to 2E for the colors B to E, similarly to the color A.

Here, the amount of the paint sucked from the feed tubes 2A to 2E should be a predetermined small amount such that a slight cavity is formed at the tip of the feed tubes 2A to 2E in order to prevent the paint from dripping. Must. If the amount of the suction paint is too small, the dripping of the paint cannot be reliably prevented. If the amount is too large, the discharge of the paint is delayed at the time of starting the next coating, resulting in poor coating.

Therefore, in the present embodiment, the suction gate valves 34A to 34A-3 are set so that the amount of the suction paint is small enough to form a slight cavity at the tip of the feed tubes 2A to 2E.
The valve opening time of 4E and the suction force of the suction pump 43 are set.

Further, in the present embodiment, as described above, the suction passage 31 is sufficiently filled with the thinner for filling, thereby preventing the occurrence of air accumulation in the suction passage 31. As a result, the paint can be accurately sucked from the feed tubes 2A to 2E by a predetermined small amount. For example, when the A-color paint is sucked, the suction gate valve 34A is set to the switching position (b) in FIG. 2 and the paint machine-side paint passage 10A and the waste liquid tank-side suction passage 33A communicate with each other. The paint in the container and the thinner in the waste liquid tank side suction passage 33A continuously contact with each other. That is, unlike the prior art, air is interposed between the paint and the thinner, and the paint and the thinner are not isolated by the air. Thereby, the suction force of the suction pump 43 is accurately and reliably transmitted to the tip of the feed tube 2A through the thinner in the waste liquid tank-side suction passage 33A and the paint in the coating machine-side paint passage 10A. Therefore, the paint in the feed tube 2A can be accurately suctioned by a predetermined small amount.

Next, the outer surfaces of the rotary atomizing head 1A and the feed tubes 2A to 2E of the coating machine 1 are cleaned. That is, by opening the coating machine cleaning valve 14, the cleaning thinner source 1 is opened.
The thinner for cleaning discharged from 3 is supplied to the thinner supply feed tube 2T of the coating machine 1 to wash off the paint adhered to the outer surfaces of the rotary atomizing head 1A and the feed tubes 2A to 2E. Then, after the cleaning is completed, the coating machine cleaning valve 14 is closed.

Next, the operation of the rotary atomizing head type coating apparatus at the time of coating and at the time of color change will be described based on the time chart shown in FIG. For example, when painting with the A color paint, the paint supply valve 4A and the paint valve 11A for the A color are opened, and the paint pump 5A is operated. Thus, the A-color paint is discharged from the A-color feed tube 2A of the coating machine 1 toward the object to be coated.

Next, when the application of the A-color paint is completed and the color is changed from the A-color paint to the B-color paint, the A-color paint pump 5
A is stopped, and the paint supply valve 4A and the paint valve 11A are closed. Thereafter, the suction gate valve 34A for A color is switched to the switching position (b) in FIG. 2 to make the paint passage 10A communicate with the waste tank suction passage 33A, and the discharge valve 42 is opened. The suction pump 43 is operated. And
In order to prevent the A-color paint from dripping from the tip of the A-color feed tube 2A, a predetermined small amount of the A-color paint is sucked from the feed tube 2A. Thereafter, the suction gate valve 34A is set to the switching position (a) in FIG.
And the suction pump 43 is stopped. Thereafter, the coating machine washing valve 14 is opened, and the thinner thinner source 1 for washing is opened.
By supplying the cleaning thinner supplied from 3 to the thinner supply feed tube 2T of the coating machine 1, the A-color paint adhered to the outer surface of the tip of the rotary atomizing head 1A, the feed tube 2A and the like is washed away.

Then, in order to perform coating with the B color paint, the B color paint supply valve 4B and the paint valve 11B are opened.
The paint pump 5B is operated. Thereby, the B color paint is discharged from the B color feed tube 2B toward the object to be coated. Then, the coating with the B color paint is completed.
When changing the color paint to another color paint, the B color paint pump 5B is stopped, and the paint supply valve 4B and the paint valve 11B are closed. Further, the suction gate valve 34B for B color is switched to the switching position (b) in FIG. 2, the paint passage 10B and the waste tank suction passage 33B are communicated, and the discharge valve 42 is opened. The suction pump 43 is operated. Thereby, a predetermined small amount of B is supplied from the B color feed tube 2B.
Suction the color paint. Thereafter, the suction gate valve 34B is set to the switching position (A) in FIG. 2, the discharge valve 42 is closed, and the suction pump 43 is stopped. Thereafter, the coating machine washing valve 14 is opened, and the B color paint adhered to the outer surface of the tip of the rotary atomizing head 1A, the feed tube 2B and the like is washed away. In addition, coating with the C color paint to the E color paint is performed in the same manner.

Further, as described above, during the coating with each color paint, the suction gate valves 34A to 34E are at the switching position (A) in FIG. 2, and the thinner source side suction passages 32A to 32E and the waste liquid tank side suction passages. 33A to 33E communicate with each other. Thus, even during the coating with each color paint, the thinner valve 36, the thinner filling valve 40, and the discharge valve 42 are opened and the suction pump 43 is operated, so that the thinner can be refilled into the suction passage 31.

Next, an operation of the rotary atomizing head type coating apparatus when the suction passage 31 is washed will be described with reference to a time chart shown in FIG. As described above, a small amount of paint may flow into the suction passage 31 due to the paint suction performed at the preparation stage before painting or at the time of color change, and this paint may adhere to the suction passage 31. If the coating operation is suspended for a long time while the paint remains in the suction passage 31, the paint may solidify in the suction passage 31 and the suction pump 43 may malfunction. In addition, the suction passage 3
If the paint adheres to the inside 1, the flow passage area of the suction passage 31 becomes small, so that there is a problem that the paint is not normally sucked. Therefore, in order to eliminate such inconvenience, for example, before pausing the painting work on the weekend,
1. Wash the suction gate valves 34A to 34E, the suction pump 43, and the like.

First, the suction gate valves 34A to 34E are
With the medium switching position (a), the thinner filling valve 40 and the discharge valve 42 are opened, and the suction pump 43 is operated. Then, the thinner valve 36 and the air valve 37 are alternately opened and closed, and the thinner and the air are alternately supplied into the suction passage 31. Thereby, the suction passage 31, the suction gate valves 34A to 34A
34E, the paint adhered to the suction pump 43 and the like is washed away.

At this time, the passage through which the thinner flows for cleaning is only the suction passage 31 provided between the thinner source 38 and the waste liquid tank 41. The paint adhered in the passage 31 can be completely washed away. That is, since the suction passage 31 has no closed path in the form of a dead end, the suction gate valves 29A to 29E are opened and the thinner is opened via the painter-side paint passages 10A to 10E, as in the prior art shown in FIG. It is not necessary to flow to the coating machine 1 side. As described above, since the cleaning can be completely performed by flowing the thinner only to the passage to be cleaned, the use efficiency of the thinner is high and the amount of the thinner can be suppressed to the minimum necessary.

Cleaning of the suction passage 31 may be performed only by flowing thinner through the suction passage 31 with the suction gate valves 34A to 34E at the switching position (a) in FIG. That is, unlike the prior art, when cleaning the suction passage, there is no need to flow thinner to the coating machine 1 via the coating machine-side coating passages 10A to 10E. Therefore, the coating machine side paint passage 10A
Without discarding the paint filled in the suction passage 3
1 can be washed. That is, it is not necessary to throw away the paint. Furthermore, since the suction passage 31 can be washed without discarding the paint filled in the paint passages 8A to 8E, the suction passage 31 can be washed even during the painting operation.

Thus, according to the present embodiment, the thinner source 3
8 and the waste liquid tank 41 are continuously connected by a suction passage 31, and suction gate valves 34 A to 34 E formed of three-way valves are provided in the middle of the suction passage 31.
In the preparation stage before painting, the suction gate valves 34A to 34A
By connecting the thinner source side suction passages 32A to 32E and the waste liquid tank side suction passages 33A to 33E through E, thinner for filling can be supplied from the thinner source 38 to the waste liquid tank 41.
And the thinner for filling can be reliably filled in the suction passage 31. That is,
Since there is no dead end-shaped closed portion having a dead end in the middle of the suction passage 31, it is possible to prevent air from being generated in the suction passage 31.

In particular, since the suction gate valves 34A to 34E are provided in parallel with the suction passage 31, the thinner can be surely spread to the suction gate valves 34A to 34E, respectively. Can be charged with thinner.

Therefore, when the paint is sucked at the time of color change or the like, the suction force of the suction pump 43 is applied to the feed tubes 2A to 2A.
The paint can be reliably transmitted to the 2E side, and the paint can be accurately sucked from the feed tubes 2A to 2E by a predetermined small amount. Thereby, the feed tubes 2A to 2
The paint can be prevented from dripping from the tip of E, and the coating failure can be eliminated.

Further, according to this embodiment, since there is no closed path in the suction passage 31, it is possible to wash the paint adhered in the suction passage 31 only by flowing the thinner only in the suction passage 31. it can. As a result, as in the prior art,
There is no need to flow thinner to a plurality of passages having different passage lengths, or to flow thinner to the coating machine 1 via the coating machine side paint passages 10A to 10E. Therefore, the suction passage 31
The amount of thinner used at the time of cleaning can be greatly reduced, the paint can be prevented from being wasted, and the cleaning operation can be simplified.

According to the present embodiment, the thinner filling valve 4
Air source 3 connected in parallel with thinner source 38 on the inflow side of
9, the suction passage 31, the suction gate valve 3
4A to 34E, the suction pump 43 and the like can be washed using thinner and air, and the paint adhered to the inside of the suction passage 31 or the like can be reliably washed away. Defects and the like can be prevented beforehand.

In the above-described embodiment, thinner is used as the solvent to fill the suction passage 31 and the like. However, the present invention is not limited to this, and other solvents such as water may be used.

[0086]

According to the first aspect of the present invention, as described in detail above, the suction passage corresponding to each paint valve and the suction passage whose base end is connected to the solvent source and whose front end is connected to the waste liquid tank. A plurality of suction gate valves provided in the middle of the passage for communicating and shutting off each painter-side paint passage with the waste tank, and communicating and shutting off between the solvent source and the waste tank; A solvent filling valve that is provided connected to the inflow side and fills the suction passage with the solvent from the solvent source, and is provided on the waste liquid tank side of each suction gate valve and provided in the middle of the suction passage; When the suction passage is filled with a solvent or a suction pump that operates when a small amount of paint is sucked from each feed tube, the solvent can be reliably filled into each suction gate valve and the suction passage, Each suction game Air reservoir can be prevented from occurring in the valve or suction passage.

Therefore, the paint in each feed tube of the coating machine can be accurately sucked by a predetermined small amount at the time of color change, and paint dripping at the tip of each feed tube can be prevented.
In addition, it is possible to prevent the paint in each feed tube from being excessively sucked, and to prevent the paint discharge timing from being delayed when performing the next painting operation, thereby preventing the occurrence of paint failure.

Further, when cleaning the paint adhered to the suction passage, it is only necessary to supply the solvent to only the suction passage connected between the solvent source and the waste liquid tank. Can be greatly reduced.

Further, as in the prior art, when cleaning the suction passage, it is necessary to flow a solvent toward the paint passage on the coating machine side and the coating machine, and to throw away the paint filled in the paint passage on the painting machine side. As a result, useless disposal of the solvent and the paint can be prevented.

According to the second aspect of the present invention, each suction gate valve is connected to a suction port connected to the paint passage on the coating machine side, an inlet port connected to the outlet side of the solvent filling valve, and a suction pump. A discharge port connected to the inflow side, the suction port being connected to the discharge port when the suction gate valve and the suction passage are filled with a solvent, and the suction port for sucking a small amount of paint from each of the feed tubes. Since it is constituted by a three-port switching valve for communicating the port and the discharge port, it is possible to prevent air from being generated in each of the suction gate valves or the suction passages in the same manner as in the first aspect of the present invention. The paint in each feed tube of the coating machine can be accurately suctioned by a predetermined small amount. Therefore, paint dripping at the tip of each feed tube can be prevented, and
Excessive suction of the paint in each feed tube can be prevented.

According to the third aspect of the present invention, since each suction gate valve is provided in parallel with the suction passage, the solvent is sufficiently filled in all of the suction passage and each suction gate valve in the coating preparation stage. Therefore, it is possible to prevent air from being generated in each suction gate or suction passage. Therefore, the same effect as that of the invention described in claim 1 or 2 is obtained.

According to the fourth aspect of the present invention, since the air source is provided together with the solvent source on the inflow side of the solvent filling valve, each suction gate valve and the suction passage can be cleaned. Accordingly, it is possible to eliminate paint clogging and the like when the rotary atomizing head type coating apparatus is not used for a long period of time.
Malfunction and failure of the device can be prevented.

[Brief description of the drawings]

FIG. 1 is a configuration explanatory view showing an overall configuration of a rotary atomizing head type coating apparatus according to an embodiment of the present invention.

FIG. 2 is a circuit diagram showing a main part of the rotary atomizing head type coating apparatus in FIG.

FIG. 3 is a time chart showing an operation of the rotary atomizing head type coating apparatus in a preparation stage before coating.

FIG. 4 is a time chart showing the operation of the rotary atomizing head type coating apparatus at the time of painting and color changing.

FIG. 5 is a time chart showing an operation of the rotary atomizing head type coating apparatus at the time of cleaning a suction passage and the like.

FIG. 6 is a configuration explanatory view showing the entire configuration of a rotary atomizing head type coating apparatus according to a conventional technique.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 coating machine 1A rotary atomizing head 2 bundle feed tube 3A to 3E paint source 8A to 8E paint passage 9A to 9E paint source side paint passage 10A to 10E painting machine side paint passage 11A to 11E paint valve 31 suction passage 34A to 34E Suction gate valve 38 Thinner source 39 Air source 40 Thinner filling valve 41 Waste liquid tank 43 Suction pump

Continuation of front page (56) References JP-A-9-998 (JP, A) JP-A-6-134355 (JP, A) JP-A-7-194999 (JP, A) JP-A-6-277571 (JP) , A) JP-A-2-90858 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B05B 5 / 04,5 / 08

Claims (4)

(57) [Claims] 1. A coating machine having a rotary atomizing head, a plurality of feed tubes provided in the coating machine and having a distal end extending into the rotary atomizing head, and a base end having a coating source for each color. A plurality of paint passages connected and the leading end side connected to each of the feed tubes, and a paint source side paint passage provided on the way of each paint passage and serving as an inflow side and a paint machine side paint passage serving as an outflow side. A rotary atomizing head type coating apparatus comprising a trigger valve for communicating and shutting off the air, a suction passage having a base end connected to a solvent source and a tip end connected to a waste liquid tank; A plurality of suction gate valves provided in the middle of the passage to communicate and shut off each of the coating machine side paint passages with the waste tank, and to communicate and shut off between the solvent source and the waste tank; Connected to the solvent inflow side of A solvent filling valve for filling the solvent from the solvent source into the suction passage; a solvent filling valve provided on the waste liquid tank side with respect to each of the suction gate valves and provided in the middle of the suction passage; And a suction pump that operates when a small amount of paint is sucked from each of the feed tubes. 2. Each of the suction gate valves has a suction port connected to the coating machine side paint passage, an inflow port connected to the outflow side of the solvent filling valve, and a discharge port connected to the inflow side of the suction pump. A port, and when each solvent is filled in the suction gate valve and the suction passage, the inflow port and the discharge port are connected, and when a small amount of paint is sucked from each of the feed tubes, the suction port and the discharge port are connected. The rotary atomizing head type coating apparatus according to claim 1, wherein the rotary atomizing head type coating apparatus is a three-port switching valve. 3. The rotary atomizing head type coating apparatus according to claim 1, wherein each of the suction gate valves is provided in parallel with a suction passage. 4. The rotary atomizing head type coating apparatus according to claim 1, wherein an air source is provided together with the solvent source on an inflow side of the solvent filling valve.