JP3207945B2 - Cleaning method for electrostatic 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 an electrostatic coating apparatus suitable for spraying a water-based paint or a solvent-based paint on an object to be coated such as a vehicle body. The present invention relates to a method for cleaning an electrostatic coating apparatus that can perform cleaning with a small amount of cleaning liquid.

[0002]

2. Description of the Related Art FIGS. 7 to 10 show a rotary atomizing head type electrostatic coating apparatus as a conventional cleaning method.

[0003] In the drawing, reference numeral 1 denotes a coating machine main body. The coating machine main body 1 is provided with an air motor 2 therein, and the air motor 2 is provided with a rotating shaft 3 which rotates at a high speed.
Here, the rotating shaft 3 is configured in a double cylindrical shape, and the outer circumferential tube is a paint pipe 6 described later, and the inner circumferential tube is a cleaning pipe 16.

[0004] Reference numeral 4 denotes a bell-shaped rotary atomizing head. The rotary atomizing head 4 is fixed to the tip end of the rotating shaft 3 of the air motor 2 and is provided outside the coating machine main body 1. I have. When the rotary atomizing head 4 is rotated at a high speed by the air motor 2 and the paint is supplied through a paint pipe 6 described later, the paint is atomized and sprayed radially outward by centrifugal force. . Further, the atomized paint is charged by, for example, an external electrode (not shown) provided outside, and is made to fly on a grounded article (not shown) to be applied.

Reference numeral 5 denotes a paint pipe. The base end of the paint pipe 5 is connected to a color changing valve device 10 described later, and the tip end is connected to the coating machine body 1. Reference numeral 6 denotes a paint pipe. The paint pipe 6 is formed in a rotating shaft 3 of an air motor 2 provided in the painter main body 1, and the paint pipe 5
And the coating machine main body 1 at the rear end. The paint pipe 6 and the paint pipe 5 constitute a paint passage 7.

Reference numeral 8 denotes a paint supply valve. The paint supply valve 8 is connected to a middle of a paint pipe 6 in the coating machine main body 1.
When the paint supply valve 8 is opened, the color changing valve device 10 is opened.
Paint, thinner and air from the rotary atomizing head 4 are supplied. Reference numeral 9 denotes a gear pump provided in the coating pipe 5.

[0007] Reference numeral 10 denotes a color change valve device as a paint supply device provided outside the coating machine main body 1. The color change valve device 10 has a paint valve of A color, B color,. 12A, 12B,... (To be referred to as a paint valve 12 as a whole), a thinner supply valve 13, and an air supply valve 14, each of which is provided with a respective color via a circulation pipe (not shown). Connected to a paint tank, thinner tank, air source, etc. Then, each valve is selectively opened to supply it to the paint pipe 5.

Reference numeral 15 denotes a washing pipe. The base end of the washing pipe 15 is connected to a washing valve device 19 described later, and the tip end of the washing pipe 15 is connected to the coating machine main body 1 through a tip washing valve 18. Reference numeral 16 denotes a cleaning pipe. The cleaning pipe 16 is formed in the rotating shaft 3 of the air motor 2 provided in the coating machine main body 1 and connected to the cleaning pipe 15 at a rear end of the coating machine main body 1. It has become. Then, the washing pipe 16 and the washing pipe 15 constitute the washing passage 17.

Reference numeral 18 denotes a front-end cleaning valve. The front-end cleaning valve 18 is provided at the rear end of the coating machine main body 1 and connects a cleaning pipe 15 and a cleaning pipe 16 which constitute a cleaning passage 17. Then, by opening the tip side cleaning valve 18,
The cleaning pipe 15 and the cleaning pipe 16 are communicated with each other to supply thinner and air to the rotary atomizing head 4.

Reference numeral 19 denotes a cleaning valve device provided outside the main body 1 of the coating machine.
A thinner supply valve 21 and a discharge valve 22 are provided on both sides of the
The thinner supply valve 21 is connected to a thinner tank (not shown) via a thinner circulation pipe 21A. When the thinner supply valve 21 is opened, thinner as a cleaning liquid is supplied to the cleaning pipe 15. On the other hand, the discharge valve 22
When the valve is opened, the cleaning passage 17 is communicated with a discharge pipe 23 to be described later, and the thinner and air in the cleaning passage 17 are discharged.

Reference numeral 23 denotes a discharge pipe as a discharge passage,
The discharge pipe 23 connects the discharge valve 22 of the washing valve device 19 and the waste liquid tank 24 via an ejector 25 described later.

Reference numeral 25 denotes an ejector as suction means,
The ejector 25 is provided in the middle of the discharge pipe 23,
When the ejector 25 is operated while the discharge valve 22 and the front end cleaning valve 18 are open, the thinner in the cleaning passage 17 is sucked and discharged to the waste liquid tank 24 through the discharge pipe 23. can do.

[0013] The rotary atomizing head type electrostatic coating apparatus according to the prior art is configured as described above.
As shown in FIG. 7, the paint valve 12 </ b> A of the color changing valve device 10 is opened, and the A-color paint is supplied to the coating machine main body 1 via the paint pipe 5 and the gear pump 9. Then, the paint supply valve 8 is opened in the coating machine main body 1 and discharged through the paint pipe 6 toward the rotary atomizing head 4 rotating at a high speed by the air motor 2. At 4, the color A paint is rotary atomized. Further, the atomized A-color paint flies along the lines of electric force generated between the external electrode and the object to be coated while being charged while passing through the corona discharge region due to the high voltage of the external electrode. Thereby, the A-color paint is applied to the object to be coated.

The hatching in the drawing indicates the flow of the paint and thinner in the passage and the open state of the valve.

On the other hand, when the painting process of the color A is completed and the paint of the next color, for example, the paint of the color B is sprayed, the paint valve 12B of the color changing valve device 10 is opened after the washing process described later. Then, the B-color paint is supplied to the coating machine main body 1 through the paint pipe 5 and the gear pump 9 to apply the B-color paint.

Next, the cleaning step will be described. here,
The cleaning process is divided into a main cleaning for cleaning the paint passage 7 and an auxiliary cleaning shown in FIGS.

First, the main cleaning for cleaning the paint remaining on and adhered to the paint pipes 5 and the paint pipes 6 will be described.

That is, in the main cleaning step, the paint supply valve 8 is opened and the thinner supply valve 13 and the air supply valve 14 are alternately provided from the color changing valve device 10 while the gear pump 9 is operated. Open valve, paint pipe 5, paint pipe 6
And it discharges to the rotary atomization head 4 alternately several times. The paint remaining in the paint pipe 5, paint pipe 6, paint supply valve 8, gear pump 9, rotary atomizing head 4 and the like due to the thinner and air is discharged from the rotary atomizing head 4 together with the thinner and air into the coating booth. Is done. At this time, the waste liquid is collected by a cleaning shroud (not shown) and discharged to a waste liquid tank.

Next, the auxiliary cleaning step will be described with reference to FIGS. In this coating process, the paint adheres to the rotary atomizing head 4 due to turbulence or the like at the time of the ejection of the paint, and is dried and fixed to become the adhered paint. In the main cleaning step described above, only the thinner or the like is sprayed from the paint passage 7 toward the rotary atomizing head 4, so that the adhered paint cannot be reliably washed. Therefore, in the cleaning step, in addition to the main cleaning of the paint passage 7 and the like described above,
Auxiliary cleaning for spot cleaning is performed, and the whole is as shown in FIG.

FIG. 9 shows a rotary atomizing head cleaning step, in which the tip side cleaning valve 18 is opened, and the thinner supply valve 21 of the cleaning valve device 19 is opened.
Is supplied to the washing passage 17, and the thinner S is supplied to the washing pipe 15.
Is discharged from the rotary atomizing head 4 through the cleaning pipe 16 to wash the paint adhered to the rotary atomizing head 4. The thinner S at this time is discharged into the coating booth. The thinner S is collected by the cleaning shroud and discharged to the waste liquid tank 24 as described above.

On the other hand, FIG. 10 shows a thinner suction step after the cleaning of the adhered paint has been completed.
Supply valve 2 of the cleaning valve device 19 in order to completely remove
1, the discharge valve 22 is opened, and the ejector 2 is closed.
Activate 5 Then, thinner remaining in the cleaning passage 17 is sucked by the ejector 25 and discharged to the waste liquid tank 24 through the discharge pipe 23.

As described above, by the main cleaning and the auxiliary cleaning in the cleaning step, the paint remaining in the paint passage 7 and the rotary atomizing head 4 and the like can be completely removed, and the next color paint is supplied to the paint passage 7. When the next color coating process is performed,
This ensures that the front color paint is prevented from being mixed in, and that the coating quality is prevented from deteriorating.

[0023]

However, in the above-described method of cleaning an electrostatic coating apparatus according to the prior art, after the end of the rotary atomizing head cleaning step of the auxiliary cleaning step, the cleaning passage 17 (the cleaning pipe 15) is drawn in the thinner suction step. In addition, since all the thinner remaining in the cleaning pipe 16) is sucked by the ejector 25 and discharged as waste liquid to the waste liquid tank 24, the amount of thinner used for the auxiliary cleaning becomes large, and the cleaning process is performed. There is a problem that the time spent on the computer becomes longer.

The present invention has been made in view of the above-mentioned problems of the prior art. The present invention reduces the amount of thinner used for cleaning in the auxiliary cleaning step of cleaning the rotary atomizing head and reduces the amount of thinner used in the rotary atomizing head. It is an object of the present invention to provide a method for cleaning an electrostatic coating apparatus that can effectively perform cleaning of the electrostatic coating device.

[0025]

The feature of the present invention to solve the above-mentioned problem is that the cleaning liquid supply valve and the front-end side cleaning valve of the cleaning valve device are opened to open the cleaning passage. A cleaning liquid supply step of supplying the cleaning liquid to the cleaning liquid supply step, and after the cleaning liquid supply step, the cleaning liquid supply valve of the cleaning valve device is closed and the air supply valve is opened to supply the cleaning liquid in the cleaning passage. A rotary atomizing head cleaning step of discharging a part to the rotary atomizing head to clean the rotary atomizing head; and closing the air supply valve of the cleaning valve device after the rotary atomizing head cleaning step. A cleaning liquid suction step of opening a discharge valve and operating a suction unit to suction a part of the cleaning liquid remaining in the cleaning passage into the discharge passage; Close the valve and open the discharge valve, activate the suction means,
And a cleaning liquid discharging step of discharging the cleaning liquid in the discharge passage to a discharge tank.

[0026]

With the above arrangement, after the cleaning liquid discharging step is completed, the cleaning liquid remains in the cleaning passage, and the remaining cleaning liquid can be used as the cleaning liquid for the rotary atomizing head at the next cleaning. .

Further, in the next rotary atomizing head cleaning step, the cleaning liquid remaining in the cleaning passage can be discharged to the rotary atomizing head by air from the air supply valve of the cleaning valve device, and a small amount of the cleaning liquid can be discharged. With this, the paint adhered to the rotary atomizing head can be washed away.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. In the embodiments, the same components as those of the above-described conventional technology are denoted by the same reference numerals, and description thereof will be omitted.

In the drawing, reference numeral 31 denotes a cleaning valve device according to the present embodiment. The cleaning valve device 31 has substantially the same configuration as the cleaning valve device 19 described in the prior art, and a thinner supply valve 33 is provided on both sides of the manifold 32. In addition to the discharge valve 34, an air supply valve 35 is provided on the thinner supply valve 33 side. The thinner supply valve 33 is connected to a thinner tank (not shown) via a thinner circulation pipe 33A. When the thinner supply valve 33 is opened, thinner as a cleaning liquid is supplied to the cleaning pipe 15. On the other hand, when the discharge valve 34 is opened, the cleaning passage 17 and the discharge pipe 23 are communicated, and thinner,
Discharge air.

Further, the air supply valve 35 is connected to an air pump 35A as an air supply source.
5 is opened, the cleaning pipe 15 or the discharge pipe 2
3 is supplied with air. The air supply valve 35 opens when the thinner for cleaning is pushed out to the rotary atomizing head 4 through the washing passage 17 and when the thinner in the discharge pipe 23 is discharged to the waste liquid tank 24. ing.

FIG. 1 shows a coating process of the A color paint.
In this coating process, the remaining cleaning thinner S0 remaining in the previous cleaning process remains in the cleaning pipe 15.

The electrostatic coating apparatus according to the present embodiment has the above-described configuration, and there is no particular difference in the operation of the basic coating process and the main cleaning process from those of the prior art.

Next, an auxiliary cleaning step of the electrostatic coating apparatus according to the present embodiment will be described with reference to FIGS.

First, FIG. 3 shows a thinner supply step at the time t1 in FIG. 2. In this step, the thinner supply valve 33 and the front end side cleaning valve 18 of the cleaning valve device 31 are opened. As a result, the cleaning thinner S1 is supplied to the cleaning pipes 15 and 16.

Next, FIG. 4 shows a rotary atomizing head cleaning step at the time t2 in FIG. 2. In this step, the thinner supply valve 33 of the cleaning valve device 31 is closed and the air supply valve 35 is opened. The cleaning thinner S1 remaining in the cleaning passage 17 in the previous step is supplied to the rotary atomizing head 4 by applying pressure to the cleaning thinner S1 by the air from the air pump 35A. Discharge a part. At this time, the paint adhered to the rotary atomizing head 4 is blown off, and a part of the cleaning thinner S1 is collected by a cleaning shroud. After the completion of this step, residual thinner S2 not discharged from the rotary atomizing head 4 remains in the cleaning pipe 16 in the cleaning passage 17.

FIG. 5 shows a thinner suction step at time t3 in FIG. 2. In this step, the air supply valve 35 of the cleaning valve device 31 is closed, while the discharge valve 34 is opened to open the manifold. The cleaning pipe 15 and the discharge pipe 23 are communicated with each other through 32, and the ejector 25 is operated. Thereby, a part of the residual thinner S2 in the cleaning passage 17 is sucked into the discharge pipe 23 side, and the residual thinner S2 is divided into the discharge pipe 23 side and the cleaning pipe 15 side. Becomes thinner S0 for residual cleaning used in the next auxiliary cleaning, and thinner remaining in the discharge pipe 23 becomes discharge thinner S3 to be discharged.

FIG. 6 shows the final thinner discharge step of the auxiliary cleaning step at time t4 in FIG. 2. In this step, the tip side cleaning valve 18 is discharged to discharge the discharge thinner S3 in the discharge pipe 23. On the other hand, the air supply valve 35 of the cleaning valve device 31 is opened, and the air supply valve 35 and the discharge pipe 23 are communicated through the manifold 32, so that not only the suction force of the ejector 25 but also the pressure of the air pump 35A As a result, the discharge thinner S3 remaining in the discharge pipe 23 is discharged to the waste liquid tank 24 instantaneously. As a result, the discharge thinner S3 in the discharge pipe 23 can be completely removed, and in preparation for the next use of the ejector 25, the clogging of the discharge pipe 23 is reliably prevented, and the function of the ejector 25 is prevented from deteriorating. ing.

As described above, in the electrostatic coating apparatus according to this embodiment, the air pressure from the air supply valve 35 is applied to the cleaning thinner S 1 supplied from the thinner supply valve 33 to the cleaning passage 17 in the auxiliary cleaning step. Is supplied to the rotary atomizing head 4 so that the paint adhered to the rotary atomizing head 4 can be effectively washed.

After the cleaning of the rotary atomizing head 4, the residual cleaning thinner S0 used for the next auxiliary cleaning remains in the cleaning pipe 15 after the cleaning is completed.
The thinner supply valve 33 is opened to the residual cleaning thinner S0 in the thinner supply step and is added to the supplied thinner to become the cleaning thinner S1, so that the thinner supply valve 33 is opened and cleaned in the auxiliary cleaning step. The amount of thinner supplied to the pipe 15 can be reliably reduced.

Further, when discharging the discharge thinner S3 in the discharge pipe 23 in the thinner discharge step, not only the suction force of the ejector 25 but also the air supply valve 35 is opened and the pressure of the air pump 35A is used to discharge the discharge thinner S3. The waste liquid tank 2
4, the discharge thinner S3 in the discharge pipe 23 can be discharged in a short time.

Thus, in the electrostatic coating apparatus according to the present embodiment, the cleaning valve device 31 is provided with the air supply valve 35 for supplying air from the air pump 35A to the cleaning pipe 15 or the discharge pipe 23. The opening of the air supply valve 35 is performed when the cleaning thinner S1 is supplied to the rotary atomizing head 4 and when the discharge thinner S3 in the discharge pipe 23 is discharged. Washing thinner S on head 4
1 can be supplied by applying pressure, and the paint adhered to the rotary atomizing head 4 can be reliably cleaned by supplying the cleaning thinner S1 once. On the other hand, the discharge thinner S3 in the discharge pipe 23
Is discharged not only by the suction of the ejector 25 but also by the pressure of the air pump 35A, so that the discharge thinner S3 in the discharge pipe 23 can be discharged to the discharge tank 25 in a short time.

Therefore, in the auxiliary cleaning step of the electrostatic coating apparatus according to the present embodiment, the amount of thinner for cleaning can be significantly reduced as compared with the prior art, and the time spent in the auxiliary cleaning step can be reduced. it can.

In the above-described embodiment, a coating apparatus using a bell-shaped rotary atomizing head has been exemplified as a rotary atomizing head type electrostatic coating apparatus. However, the present invention is not limited to this. Thus, the present invention may be applied to an electrostatic coating apparatus using a disk-type rotary atomizing head.

[0044]

As described above in detail, in the cleaning method of the electrostatic coating device according to the present invention, the cleaning liquid supply valve and the front-end cleaning valve of the cleaning valve device are opened, and the cleaning liquid is supplied into the cleaning passage. Cleaning liquid supply step of supplying the cleaning liquid, and after the cleaning liquid supply step, the cleaning liquid supply valve of the cleaning valve device is closed and the air supply valve is opened, and a part of the cleaning liquid in the cleaning passage is removed. A rotary atomizing head cleaning step of discharging to the rotary atomizing head to clean the rotary atomizing head; and, after the rotary atomizing head cleaning step, closing and discharging the air supply valve of the cleaning valve device. Is opened, the suction means is operated, and a cleaning liquid suction step of suctioning a part of the cleaning liquid remaining in the cleaning path to the discharge path; and, after the cleaning liquid suction step, the front-end side cleaning valve is closed. Open the discharge valve while opening the valve, activate the suction means, and discharge the cleaning liquid in the discharge passage. Since the cleaning liquid is discharged in four steps, the cleaning liquid is left in the cleaning passage at the end of the cleaning, so that the cleaning liquid to be supplied at the next cleaning is maintained. The amount can be reduced. Further, the air supply valve of the cleaning valve device supplies air to the rotary atomizing head cleaning step and the cleaning liquid discharging step, so that the paint adhered to the rotary atomizing head can be reliably cleaned and a short time can be achieved. The cleaning of the rotary atomizing head and the discharge of the cleaning liquid in the discharge pipe can be carried out, and the time of the cleaning step can be significantly reduced.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of an electrostatic coating apparatus used in a cleaning method according to the present embodiment.

FIG. 2 is a time chart showing an auxiliary cleaning step according to the embodiment.

FIG. 3 is an explanatory view showing a thinner supply step at a time t1 in FIG. 2;

FIG. 4 is an explanatory view showing a rotary atomizing head cleaning step at a time t2 in FIG. 2;

FIG. 5 is an explanatory view showing a thinner suction step at time t3 in FIG. 2;

FIG. 6 is an explanatory diagram showing a thinner discharging step at time t4 in FIG. 2;

FIG. 7 is an overall configuration diagram of an electrostatic coating apparatus used in a cleaning method according to the related art.

FIG. 8 is a time chart showing an auxiliary cleaning step according to the related art.

FIG. 9 is an explanatory view showing a rotary atomizing head cleaning step at a time tA in FIG. 8;

FIG. 10 is an explanatory diagram showing a thinner suction step at time tB in FIG. 8;

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 coating machine main body 2 air motor 3 rotating shaft 4 rotating atomizing head 5 paint pipe 6 paint pipe 7 paint passage 8 paint supply valve 10 color changing valve device 15 washing pipe 16 washing pipe 17 washing passage 18 tip side washing valve 23 discharge pipe 24 Waste liquid tank 25 Ejector (suction means) 31 Cleaning valve device 33 Thinner supply valve 34 Discharge valve 35 Air supply valve 35A Air pump

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-61-46279 (JP, A) JP-A-61-46271 (JP, A) JP-A 5-39670 (JP, U) JP-A 2-46 37766 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) B05B 5 / 04,5 / 08

Claims (1)

(57) [Claims] A coating machine main body; an air motor provided in the coating machine main body; and an air motor inserted in an axial direction of the air motor;
A rotary shaft rotated by the air motor, a rotary atomizing head provided on a tip end side of the rotary shaft, and a paint, cleaning liquid, and air from a paint supply device provided outside the coating machine main body. A paint passage for selectively supplying a coating head, a washing passage for selectively supplying a cleaning liquid and air from a cleaning valve device provided outside the coating machine main body to the rotary atomizing head, And a suction means for discharging a cleaning liquid remaining in the cleaning passage to a waste liquid tank via the cleaning valve device, wherein the cleaning is provided. the valve apparatus comprises wash liquid supply valve for supplying cleaning liquid to the cleaning passage, a discharge valve for discharging the air supply valve for supplying air to the cleaning passage, in the waste liquid tank through the discharge passage cleaning liquid in the cleaning passage Electrostatic coating device comprising In the cleaning method, the cleaning liquid supply valve and the front-end side cleaning valve of the cleaning valve device are opened to supply a cleaning liquid into the cleaning passage. The cleaning liquid supply valve of the cleaning valve device is closed and the air supply valve is opened, and a part of the cleaning liquid in the cleaning passage is discharged to the rotary atomizing head to clean the rotary atomizing head. After the head cleaning step and the rotary atomizing head cleaning step, the air supply valve of the cleaning valve device is closed and the discharge valve is opened, the suction means is operated, and the cleaning remaining in the cleaning passage is performed. A washing liquid suction step of sucking a part of the liquid into the discharge passage, and after the washing liquid suction step, the front-end side washing valve is closed and the discharge valve is opened, and the suction means is operated, and the inside of the discharge passage is opened. Cleaning liquid discharging step of discharging the cleaning liquid to the discharge tank. Method for cleaning an electrostatic coating device according to.