JPH05285424A - Intermediate storage tank of electrostatic painting apparatus - Google Patents

Abstract

PURPOSE:To improve the cleaning function in the case of cleaning an intermediate storage tank at the time of color change and carry out highly efficient and precise painting while effectively preventing the color mixing of paints before and after color change. CONSTITUTION:An electrostatic painting apparatus is provided with a cylinder 12, a piston 14 set in the cylinder 12, a pouring hole parts 18a, 18b formed in the periphery of an inner side circumferential part 17, and a discharging hole part 20 formed in the central part of the cylinder container wall 16 and the cylinder container wall 16 is composed of recessed taper faces tilting toward inside from the inner circumferential part 17 to the central part. The tip end face 28 of a piston main body 23 which constitutes the piston 14 is composed of projected taper faces projected outward from the circumferential wall part 14a to the central part and the width of the gap S0 formed between the cylinder container wall 16 and the tip end face 28 becomes continuously narrower toward the discharging hole part 20 in the central part from the inner side circumferential wall part 17.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intermediate storage tank of an electrostatic coating apparatus configured to temporarily store paint in a cylinder, supply the paint to a coating gun, and clean the inside of the cylinder with a cleaning liquid. Regarding

[0002]

2. Description of the Related Art Conventionally, an intermediate storage tank is provided between a coating gun and a coating supply source as one form of an electrostatic coating apparatus for conductive coating.

[0003] At the time of color change with a newly used paint, various innovations and improvements have been made in order to avoid color mixture with a new paint due to residual paint remaining in the intermediate storage tank. It was As one example, US Pat.
No. 1729 "SYSTEM FOR AUTOMATIC ELECTROSTATIC S
PRAY COATING ", Japanese Patent Laid-Open No. 63-310671," method of sequentially coating an article to be processed with a conductive coating material "and the like can be mentioned.

[0004]

However, the "SYSTEM FOR AUT" disclosed in the above-mentioned US Pat. No. 4,771,729 is disclosed.
In the technical concept related to "OMATIC ELECTROSTATIC SPRAY COATING", the cleaning liquid is sprayed only toward the end face of the piston when cleaning the inside of the intermediate storage tank at the time of color change. At the peripheral portion, the disadvantage that the paint before color change is not completely removed is exposed.

Further, in the technical idea relating to "a method of sequentially coating an article to be processed with a conductive coating material" disclosed in JP-A-63-310671, in the intermediate storage tank at the time of color change, At the time of cleaning, the flow of the cleaning liquid is not sufficient, and the paint on the end surface of the piston has not been sufficiently removed.

Therefore, in order to overcome the above inconvenience, it is necessary to perform cleaning with the piston retracted, and there is an inconvenience that the cleaning time is prolonged and a large amount of cleaning liquid is required.

The present invention has been made in order to solve this kind of problem, and it is possible to improve the cleaning ability at the time of cleaning the intermediate storage tank at the time of color change, and to mix the paint before and after the color change. It is an object of the present invention to provide an intermediate storage tank of an electrostatic coating device capable of effectively blocking and effectively and accurately performing coating.

[0008]

In order to achieve the above object, the present invention provides a cylinder, a piston disposed in the cylinder so as to be reciprocally slidable, and a cylinder wall near the inner peripheral wall. The cylinder unit is provided with an injection hole portion provided and connected to a supply source of paint and cleaning liquid, and a discharge hole portion of the paint and cleaning liquid which is provided in a central portion of the cylinder wall and connected to a coating gun. The width of the gap formed between the wall and the end surface of the piston decreases from the inner peripheral wall portion of the cylinder wall toward the central portion.

Further, according to the present invention, a cylinder, a piston reciprocally slidably arranged in the cylinder, a piston provided near an inner peripheral wall of a cylinder wall, and connected to a supply source of paint and cleaning liquid. An injection hole portion and a discharge hole portion for the paint and the cleaning liquid, which is provided in the central portion of the cylinder wall and is connected to the coating gun, are provided, and a gap formed by the cylinder wall and the end surface of the piston is formed. The width increases from the inner peripheral wall portion of the cylinder wall toward the central portion.

[0010]

In the intermediate storage tank of the electrostatic coating apparatus according to the present invention described above, when cleaning the intermediate storage tank at the time of color change, the cleaning liquid is introduced into the cylinder from the injection hole provided near the inner peripheral wall of the cylinder wall. When the cleaning liquid is supplied, the cleaning liquid is discharged to the outside through a discharge hole provided in the central portion of the cylinder wall. At that time, the width of the gap formed between the cylinder wall and the end face of the piston becomes smaller from the inner peripheral wall portion of the cylinder wall toward the central portion, so that the flow velocity of the cleaning liquid at the central portion increases. Cleaning of the piston and cylinder walls is improved.

Furthermore, in the intermediate storage tank of the electrostatic coating apparatus according to the present invention, the width of the gap formed between the cylinder wall and the end face of the piston extends from the inner peripheral wall of the cylinder wall toward the center. Since the cleaning liquid becomes large, the cleaning liquid can smoothly flow to the discharge hole portion side, and since a particularly large amount of cleaning liquid can be supplied in a short time, the cleaning work can be efficiently performed.

[0012]

EXAMPLES Examples of an intermediate storage tank of an electrostatic coating apparatus according to the present invention will be described below with reference to the accompanying drawings.

In FIG. 1, reference numeral 10 indicates an intermediate storage tank of the electrostatic coating apparatus according to the first embodiment. The intermediate storage tank 10 is provided with a cylinder 12, a piston 14 reciprocally slidably arranged in the cylinder 12, a cylinder device wall 16 corresponding to the vicinity of the inner peripheral wall portion 17, and Two injection holes 18a and 18b (see FIG. 2) connected to a supply source (described later), and discharge of paint and cleaning liquid connected to a coating gun described below which is provided in the center of the cylinder wall 16 A seal member 22 made of a polymer material, for example, a polyethylene resin, is provided on the peripheral wall portion 14a of the piston 14 having a hole 20.

The cylinder wall 16 is composed of a concave taper surface that is inclined inward from the inner peripheral wall portion 17 toward the center, that is, in a direction away from the piston 14, and at a boundary portion with the inner peripheral wall portion 17 and Arc-shaped chamfers R1 and R2 are provided at the boundary with the discharge hole 20 (see FIG. 3).

The piston 14 is provided with a piston body 23 and a piston rod 24. The piston body 23 is fixed to the tip portion of the piston rod 24, and the peripheral wall portion 1 thereof is provided.
The outer peripheral side portions 23a and 23b provided on the inner peripheral wall 4a are in close contact with the inner peripheral wall portion 17. A peripheral groove 26 is formed between the outer peripheral side portions 23a and 23b, and the inside of the peripheral groove 26 is filled with water or a mixed liquid of water and glycerin. In the peripheral wall portion 14a,
A seal member 22 having a U-shaped cross section or a V-shaped cross section is disposed outside the outer peripheral side portions 23a and 23b that define the circumferential groove 26.

The tip end surface 28 of the piston body 23 is formed of a convex tapered surface projecting outward from the peripheral wall portion 14a toward the central portion, that is, toward the cylinder device wall 16 side, and the top portion 30 thereof is a discharge hole portion. 20 is formed so as to project.
A gap S0 is formed between the cylinder wall 16 and the tip surface 28, and the width of the gap S0 continuously decreases from the inner peripheral wall portion 17 toward the central discharge hole portion 20. The tip surface 28, the cylinder wall 16, and the inner peripheral wall portion 17
The first cylinder chamber 32 is formed by and the other second cylinder chamber 34 divided by the piston body 23 is supplied with air as a drive source for sliding the piston 14 in the arrow X1 direction. Further, an air hole portion 36 is formed to discharge the supplied air to the outside.

The intermediate storage tank 10 is an insulator as a whole because it can be used in the voltage block method, which is one of the electrostatic coating methods. In some cases, the intermediate storage tank 10 is used. Can be surrounded by an insulator so as to have the same function, that is, an insulating function.

Next, the overall structure of the electrostatic coating device in which the intermediate storage tank 10 is interposed will be described.

As shown in FIG. 4, in the electrostatic coating apparatus, the intermediate storage tank 10 includes a color changing valve mechanism 50, which is a grounded paint supply source for selectively supplying a plurality of different paints, and a coating gun 52. It is interposed between.

A supply path 54 is provided between the intermediate storage tank 10 and the color change valve mechanism 50, and an electrically insulating conduit 56 is provided at least partially in the middle of the supply path 54. 5
A block valve mechanism 60 to which switching valves 58a and 58b are connected is arranged on both sides of 6. The color change valve mechanism 50 includes a first cleaning valve 62 that controls the supply of air (A), water (W), cleaning liquid (S), and the like, and a plurality of paint valves 64a to 64e that can supply different paints. It has and.

A color changing valve mechanism 50 is provided by a switching valve 58a on the inlet side which constitutes the block valve mechanism 60, and a second washing valve 66 which controls the supply of air (A), water (W), washing liquid (S) and the like. Is connected to the intermediate storage tank 10 via the supply path 54 from the outlet side switching valve 58b, and the switching valve 58b is connected to the waste liquid tank 7 via the discharge path 68.
It is possible to communicate with 0. The supply passage 54 is branched into two passages through a manifold or the like and communicates with the injection hole portions 18a and 18b, and the distance between the branched portions and the opening to the first cylinder chamber 32 is equal to each other. While being set to be the same, the sum of the opening cross-sectional areas of the paths after branching and the opening cross-sectional area of the supply path 54 before branching are selected to be substantially the same.

The second cylinder chamber 34 of the intermediate storage tank 10
The air supply source 74 communicates with the valve 14 via the flow rate adjusting valve 76, the opening / closing valve 78, and the air hole 36, and drives the piston 14 in the direction of arrow X1. The air supply source 74 is connected via a booster 80 to a paint flow rate controller 82 for adjusting the air pressure. The flow rate controller 82 controls the discharge amount of the paint.

Between the intermediate storage tank 10 and the coating gun 52, there is provided a delivery passage 84 in which a flow rate controller 82 is interposed. The coating gun 52 has a dump valve 86 and a trigger valve 88.
And is connected to a high voltage applying means (not shown).

Next, the operation of the electrostatic coating apparatus thus constructed will be described.

In electrostatic coating, first, as shown in FIG. 4, the paint of a predetermined color is pressure-fed from the paint valve 64a of the color changing valve mechanism 50, and the supply passage 54 and the injection holes 18a, 18b.
The first cylinder chamber 32 of the intermediate storage tank 10 is filled via the above, and further the coating gun 52 is filled via the delivery passage 84. During this filling, the trigger valve 88 is closed while the dump valve 86 is opened, and the dump valve 8 is filled after filling.
6 is closed.

Therefore, the switching valve 58 of the block valve mechanism 60
The switching operation between a and 58b is performed, the block valve mechanism 60 is cleaned under the driving action of the second cleaning valve 66, and the cleaning liquid used for this cleaning is discharged through the discharge path 68 to the waste liquid tank 7
It is discharged to 0. Then, the block valve mechanism 60 is dried, whereby the color change valve mechanism 50 and the intermediate storage tank 10 are
Electrically isolated.

Next, from the air supply source 74 to the flow rate adjusting valve 76.
Driving air is supplied to the second cylinder chamber 34 of the intermediate storage tank 10 via the open / close valve 78, and the piston 14 moves to the first position.
While being displaced to the cylinder chamber 32 side, a high voltage applying means (not shown) is driven. As a result, the paint is applied to the work (not shown) under the opening action of the trigger valve 88 in the state where the high voltage is directly applied.

By the way, when the color of the paint used in the painting operation is changed, the application of the high voltage to the paint is released and the switching valves 58a and 58b of the block valve mechanism 60 are switched, and then the first cleaning valve. The cleaning liquid is driven from the injection hole portions 18 a and 18 b by driving 62 to the first cylinder chamber 3 of the intermediate storage tank 10.
Injected into 2. At that time, as shown in FIG. 3, the injection holes 18a and 18b are provided in the vicinity of the inner peripheral wall portion 17, and the width of the gap S0 formed by the cylinder wall 16 and the tip surface 28 of the piston body 23 is reduced. , The inner peripheral wall portion 1
It is continuously reduced from 7 toward the central discharge hole 20. Therefore, the cleaning liquid (see the arrow in FIG. 3) supplied from the injection hole portions 18a and 18b to the vicinity of the inner peripheral wall portion 17 can flow toward the discharge hole portion 20 while increasing the flow velocity thereof, It is possible to quickly and reliably wash the inner peripheral wall portion 17, the cylinder wall 16 and the tip end surface 28 of the piston body 23.

Particularly, in the first cylinder chamber 32, the gap S0 has a large width on the inner peripheral wall portion 17 side, and the cleaning liquid is likely to remain on the inner peripheral wall portion 17 side, that is, the seal member 22 side. Therefore, when the cleaning liquid is supplied from the injection hole portions 18a and 18b to the vicinity of the inner peripheral wall portion 17, a eddy flow is generated between the cleaning liquid remaining near the inner peripheral wall portion 17 and the seal member 22 and the inner side. Perimeter wall 1
7 has the advantage that it can be washed more reliably.

Further, the cylinder wall 16 is provided with arcuate chamfered portions R1 and R2 corresponding to the boundary portion with the inner peripheral wall portion 17 and the boundary portion with the discharge hole portion 20, and the first cylinder chamber. The flow of the cleaning liquid in 32 becomes smoother, and effective cleaning properties are obtained. At that time, the discharge hole portion 20 is provided at the center of the tip surface 28 of the piston body 23.
The top portion 30 projecting to the side is formed, whereby the flow of the cleaning liquid and the cleaning property can be easily improved.

Further, the distances of both paths from the branch portion of the supply path 54 to the opening to the first cylinder chamber 32 are set to be the same, and the sum of the opening cross-sectional areas of the paths after the branch and the branch area before the branch. The opening cross-sectional area of the supply passage 54 is selected to be substantially the same. Therefore, for example, if the route after branching is blocked,
The pressure in the supply passage 54 rises, and an abnormality in this route can be easily detected. Therefore, even if a partial decrease in the cleaning property is caused due to the clogging of the route, this can be reliably performed. It becomes possible to detect.

The cleaning work is preferably performed by alternately supplying the cleaning liquid and the drying air. Particularly, the number of times of switching between the cleaning liquid and the drying air is increased within a certain cleaning time. Thereby, the cleaning property can be further improved.

Next, the intermediate storage tank 100 of the electrostatic coating apparatus according to the second embodiment of the present invention will be described with reference to FIG. The same components as those of the intermediate storage tank 10 according to the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

The cylinder wall 102 constituting the intermediate storage tank 100 is formed of a convex taper surface which is inclined outward from the inner peripheral wall portion 17 toward the center portion, that is, in the direction close to the piston 14. Arc-shaped chamfered portions R3 and R4 are provided at a boundary portion with the inner peripheral wall portion 17 and a boundary portion with the discharge hole portion 20.

Piston body 23 constituting the piston 14
The front end surface 104 of the is formed by a concave taper surface that is inclined inward from the peripheral wall portion 14a toward the central portion, that is, in the direction away from the cylinder wall 16,
The top portion 106 of No. 4 is formed so as to project toward the discharge hole portion 20. A gap S1 is formed between the cylinder wall 102 and the tip end surface 104, and the width of the gap S1 continuously decreases from the inner peripheral wall portion 17 toward the central discharge hole portion 20.

In the intermediate storage tank 100 thus constructed, the cleaning liquid injected into the first cylinder chamber 32 through the injection holes 18a and 18b is formed by the cylinder wall 102 and the tip surface 104 of the piston body 23. Since the cleaning liquid flows along the gap S1, the cleaning liquid can flow toward the discharge hole portion 20 while increasing the flow velocity thereof. Therefore, as in the case of the intermediate storage tank 10 according to the first embodiment, an effect that an efficient and reliable cleaning work is performed can be obtained.

Furthermore, an intermediate storage tank 200 of an electrostatic coating apparatus according to the third embodiment of the present invention will be described with reference to FIG. The intermediate storage tank 1 according to the first embodiment
The same components as 0 are designated by the same reference numerals, and detailed description thereof will be omitted.

Cylinder wall 202 which constitutes this intermediate storage tank 200 is constituted by a concave taper surface which is inclined inward from inner peripheral wall portion 17 toward the central portion, that is, in a direction away from piston 14, and inside thereof. Arc-shaped chamfered portions R5 and R6 are provided at a boundary portion with the peripheral wall portion 17 and a boundary portion with the discharge hole portion 20.

Piston body 23 constituting the piston 14
The front end surface 204 of the above is constituted by a convex taper surface projecting outward from the peripheral wall portion 14a toward the central portion, that is, the cylinder wall 202 side, and a gap S2 is formed between the front end surface 204 and the cylinder wall 202. While being formed, the width of the gap S2 is set such that the inner peripheral wall portion 17 extends to the central discharge hole portion 2
It is continuously increasing toward 0.

In the intermediate storage tank 200, the width of the gap S2 formed between the cylinder wall 202 and the tip end surface 204 of the piston body 23 is increased toward the discharge hole portion 20 and the injection hole portion is increased. The cleaning liquid injected into the first cylinder chamber 32 from 18a and 18b can reduce the back pressure when being discharged from the discharge hole portion 20. Therefore, the first
Since the flow of the cleaning liquid in the cylinder chamber 32 becomes smoother, a particularly large amount of cleaning liquid can be supplied in a short time,
The effect that the efficiency of the entire cleaning work is easily achieved is obtained.

[0041]

According to the intermediate storage tank of the electrostatic coating apparatus of the present invention, the following effects can be obtained.

When cleaning the intermediate storage tank at the time of color change, when the cleaning liquid is supplied into the cylinder from the injection hole portion provided in the vicinity of the inner peripheral wall portion of the cylinder device wall, the cleaning liquid is supplied to the cylinder device wall and the piston. It is discharged to the outside through a discharge hole formed in the center of the cylinder wall through a gap formed by the end surface of the cylinder. At that time, since the width of the gap becomes smaller from the inner peripheral wall portion of the cylinder wall toward the central portion, the flow velocity of the cleaning liquid on the central portion side is increased to improve the cleaning performance of the piston and the cylinder wall. The efficiency of the cleaning work can be easily achieved.

Furthermore, in the intermediate storage tank of the electrostatic coating apparatus according to the present invention, the width of the gap formed between the cylinder wall and the end face of the piston extends from the inner peripheral wall of the cylinder wall toward the center. Since the cleaning liquid becomes large, the back pressure becomes small and the cleaning liquid can smoothly flow to the discharge hole side.
Therefore, since a particularly large amount of cleaning liquid can be supplied in a short time,
The cleaning work can be performed more quickly.

[Brief description of drawings]

FIG. 1 is a partially longitudinal explanatory view of an intermediate storage tank of an electrostatic coating device according to a first embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II in FIG.

FIG. 3 is a vertical cross-sectional explanatory view of a main part of the intermediate storage tank.

FIG. 4 is a schematic configuration explanatory view of an electrostatic coating device incorporating the intermediate storage tank.

FIG. 5 is a vertical cross-sectional explanatory view of an essential part of an intermediate storage tank of an electrostatic coating apparatus according to a second embodiment of the present invention.

FIG. 6 is a vertical cross-sectional explanatory view of an intermediate storage tank of an electrostatic coating apparatus according to a third embodiment of the present invention.

[Explanation of symbols]

 10 ... Intermediate storage tank 12 ... Cylinder 14 ... Piston 14a ... Peripheral wall part 16 ... Cylinder wall 17 ... Inner peripheral wall part 18a, 18b ... Injection hole part 20 ... Discharge hole part 22 ... Sealing member 28 ... Tip surface 30 ... Top part 32, 34 ... Cylinder chamber 50 ... Color change valve mechanism 52 ... Painting gun 60 ... Block valve mechanism 100 ... Intermediate storage tank 102 ... Cylinder wall 104 ... Tip surface 106 ... Top 200 ... Intermediate storage tank 202 ... Cylinder wall 204 ... Tip surface S0, S1, S2 ... Gap

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[Procedure amendment]

[Submission date] April 30, 1992

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Correction target item name] All drawings

[Correction method] Change

[Correction content]

[Figure 1]

[Fig. 2]

[Figure 3]

[Figure 4]

[Figure 5]

[Figure 6]

Front page continuation (72) Inventor Nobunari Arai 1-10-1 Shin-Sayama, Sayama-shi, Saitama Honda Engineering Co., Ltd. (72) Inventor Ichiro Ishibashi 1-10-1 Shin-Sayama, Sayama-shi, Saitama Honda Engineering Co., Ltd. In the company

Claims (2)

[Claims] 1. A cylinder, a piston reciprocally slidably arranged in the cylinder, and an injection hole portion provided in the vicinity of an inner peripheral wall portion of a cylinder wall and connected to a supply source of paint and cleaning liquid. And a discharge hole for a paint and a cleaning liquid, which is provided in a central portion of the cylinder wall and is connected to a coating gun, and a width of a gap formed between the cylinder wall and the end surface of the piston is An intermediate storage tank of an electrostatic coating apparatus, which is characterized in that the inner peripheral wall portion of the cylinder device wall decreases toward the central portion. 2. A cylinder, a piston reciprocally slidably arranged in the cylinder, and an injection hole portion provided in the vicinity of an inner peripheral wall portion of a cylinder wall and connected to a supply source of paint and cleaning liquid. A discharge hole for the paint and the cleaning liquid, which is provided in the center of the cylinder wall and is connected to the coating gun, and the width of the gap formed between the cylinder wall and the end face of the piston is An intermediate storage tank for an electrostatic coating device, which is characterized in that the size increases from the inner peripheral wall of the cylinder wall toward the center.