JPH04243564A - Electric leakage preventive structure for electrostatic coater - Google Patents

Abstract

PURPOSE:To permit an effective prevention of the electric leakage from devices such as valve and intermediate paint reservoir tank as well as an easy shortening of length of the pipes connected to such devices. CONSTITUTION:An electric leakage preventing structure which includes a four- way transfer valve 50 made of an electrically conductive material for use in a coater for effecting an electrostatic coating by applying voltage to an electrically conductive coating material and enclosed with a container 72 made of insulating material; a passage 78 formed in the container 72 and capable of freely communicating with the four-way valve transfer 50; and a covering member 74 made of insulating material with which the container 72 is enclosed, the creeping distance L between the container 72 and the covering member 74 being made greater than needed to prevent the electric leakage to thereby permit an effective prevention of the electric leakage by applying high voltage.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an earth leakage prevention structure for equipment such as valves and intermediate storage tanks used in coating equipment that performs electrostatic coating by applying voltage to conductive paint.

0002

2. Description of the Related Art Conventionally, coating apparatuses for applying electrostatic coating to objects to be coated such as automobile bodies by applying high voltage to conductive coating materials have been used. A replacement system is known.

[0003] In this prior art, the conductive paint is once introduced into an intermediate storage tank (reservoir) insulated from ground potential, and then supplied from this intermediate storage tank to the object to be coated, thereby performing electrostatic coating. In addition to this intermediate storage tank, various valves are used to selectively switch between conductive paint, cleaning fluid, and air.

0004

[Problems to be Solved by the Invention] However, in the above-mentioned conventional technology, a considerably high voltage is applied up to the intermediate storage tank, so it is necessary to insulate the intermediate storage tank and various valves and other equipment. Must be configured. however,
Devices made of insulating materials have problems with accuracy and strength, and also have the disadvantage of rising manufacturing costs.

[0005]Furthermore, in the above-mentioned equipment, the pipe body is connected through a joint, and current leakage is likely to occur from this joint, and when a conductor such as a person approaches, there is a problem that electric discharge occurs due to dielectric breakdown. is pointed out. As a result, various equipment cannot be placed inside the paint booth or near electrical conductors, and the length of the pipe leading to the paint gun becomes long, resulting in a large amount of wasted paint when changing colors. , the cleaning time and cleaning solution usage increases.

The present invention solves this type of problem, and can effectively prevent electrical leakage from equipment such as valves and intermediate storage tanks, and can easily connect pipes connected to this equipment. The purpose of the present invention is to provide an earth leakage prevention structure for electrostatic coating equipment that can be made shorter in length.

[0007]

[Means for Solving the Problems] In order to achieve the above-mentioned object, the present invention provides conductive materials for valves, intermediate storage tanks, etc. used in coating equipment that performs electrostatic painting by applying voltage to conductive paint. a container made of an insulating material that encloses the device and forms a paint passage that can freely communicate with the device; and a cover member that encloses the container, and is composed of the container and the cover member. It is characterized in that the creepage distance is selected to be greater than or equal to the required creepage length that can prevent electrical leakage.

Furthermore, the present invention includes devices made of conductive materials such as valves and intermediate storage tanks used in a coating device that performs electrostatic coating by applying voltage to conductive paint, and includes the devices, and also includes the devices. a container made of an insulating material in which a paint passage is formed that can freely communicate with the container; a cover member enclosing the container; and an insulating seal member disposed between the container and the cover member. The creepage distance is selected to be less than or equal to the required creepage length that can prevent electric leakage.

[0009]

[Function] In the leakage prevention structure for electrostatic coating equipment according to the present invention, the valves, intermediate storage tank, and other equipment are made of conductive materials, so that desired precision and strength can be ensured. The device is covered with a container made of an insulating material and a cover member, and the creepage distance formed by the container and the cover member is selected to be greater than the necessary creepage length that can prevent electric leakage. Even if a high voltage is applied to the device, leakage can be effectively prevented.

Furthermore, even if the creepage distance between the container and the cover member is selected to be less than or equal to the required creepage length that can prevent electrical leakage, the sealing effect of the insulating seal member
It is possible to effectively prevent electrical leakage from occurring due to the application of high voltage.

[0011]

EXAMPLES Examples of the leakage prevention structure for electrostatic coating according to the present invention will be described below with reference to the accompanying drawings.

In FIG. 2, reference numeral 10 indicates a coating apparatus incorporating the leakage prevention structure for electrostatic coating according to the first embodiment. This coating device 10 includes a color change valve mechanism 12,
This color change valve mechanism 12 includes a first cleaning valve 14 that controls the supply of air (A), water (W), cleaning liquid (S), etc., and a plurality of paint valves 16a that can supply different paints. 16c to 16c are provided. The color change valve mechanism 12 is connected to a supply path 20 in which a block valve mechanism 18 that has an electrically insulating pipe line at least in part and includes the electrically insulating pipe line is arranged.

This block valve mechanism 18 has a switching valve 22a.
, 22b, and the color change valve mechanism 12 and a second cleaning valve 24 that controls the supply of air (A), water (W), cleaning liquid (S), etc. are switched by the switching valve 22a on the inlet side. , are connected to an intermediate storage tank 26 via a supply path 20. This intermediate storage tank 26 includes a first cylinder chamber 30 for injecting paint and cleaning liquid and a second cylinder chamber 32 for supplying air, which are divided via a piston 28 . A source 34 communicates with the flow rate regulating valve 36 and an on-off valve 38 . This air supply source 34 is connected via a booster 40 to a paint flow rate regulator 42 for adjusting air pressure, and the flow rate regulator 42 controls the amount of paint discharged. The switching valve 22b is connected to a waste liquid tank 46 via a discharge path 44.

A four-way switching valve 50 is connected to the first cylinder chamber 30 of the intermediate storage tank 26 via a delivery path 48a, and this four-way switching valve 50 connects to the flow rate regulator 4 via a delivery path 48b.
2 and a coating gun 52. This four-way switching valve 50
A third cleaning valve 54 that controls the supply of air (A), water (W), cleaning liquid (S), etc. is connected to a waste liquid tank 58 via a discharge path 56, and the painting gun 52 It includes a dump valve 60 and a trigger valve 62, and is connected to high voltage application means (not shown).

In the coating apparatus 10 configured as described above, the four-way switching valve 50 is provided with the earth leakage prevention structure 70 according to this embodiment.
will be provided.

As shown in FIG. 1, this earth leakage prevention structure 70
The four-way switching valve 50 described above is made of a conductive material, and the container 7 made of an insulating material contains the four-way switching valve 50.
2, and a cover member 74 that encloses the container 72. This container 72 is formed of a resin material such as polyacetal, and includes a first passage (not shown) communicating the delivery passage 48a and the four-way switching valve 50, and the four-way switching valve 50.
0 and a second passage 78 that communicates with the discharge passage 56. A four-way switching valve 50 and a delivery path 4 are provided on the wall 72a of the container 72.
8b is provided. This connecting means 80 includes a joint member 82 screwed into the wall 72a, and a nut member 86 for connecting the delivery passage 48b to the joint member 82 and communicating the delivery passage 48b with the passage 84 in the joint member 82. and a pipe member 88 that covers the joint member 82 and the nut member 86.

The cover member 74 is made of a resin material such as polyacetal and has a substantially cylindrical shape with one end closed.
It is fixed to the container 72 by. The creepage distance L where the cover member 74 and the container 72 are in direct contact is selected to be greater than or equal to the necessary creepage length that can prevent electrical leakage, specifically, -60
When a voltage of kV is applied, the creepage distance L is 200mm
selected above. A passage 76 for supplying driving air for switching the four-way switching valve 50 is formed in the container 72, and an end of this passage 76 is connected to an air supply path (not shown).

Next, the operation of the leakage prevention structure 70 constructed as described above will be explained. First, when performing electrostatic painting using the painting device 10, as shown in FIG.
The paint of a predetermined color is fed under pressure from the paint valve 16a, and is filled into the first cylinder chamber 30 of the intermediate storage tank 26 via the supply path 20, and further via the delivery path 48a, the four-way switching valve 50, and the delivery path 48b. The paint gun 52 is then filled. During this filling, the trigger valve 62 is closed, while the dump valve 60 is opened, and after filling, the dump valve 60 is closed.

Therefore, the switching valve 22 of the block valve mechanism 18
When the switching operations a and 22b are performed, the block valve mechanism 18 is cleaned under the driving action of the second cleaning valve 24, and the cleaning liquid used for this cleaning is sent to the waste liquid tank 46 via the discharge path 44. It is discharged. Then, the block valve mechanism 18 is dried, and thereby the color change valve mechanism 12 and the intermediate storage tank 26 are electrically insulated.

Next, the air supply source 34 is connected to the flow rate regulating valve 36.
Driving air is supplied to the second cylinder chamber 32 of the intermediate storage tank 26 via the on-off valve 38, and the piston 28 moves into the first cylinder chamber 32.
It is displaced to the cylinder chamber 30 side, and paint is applied to a workpiece (not shown) under the opening action of the trigger valve 62 while a high voltage is applied.

In this case, in this embodiment, the four-way switching valve 50
Since it is made of a conductive material, the strength of the four-way switching valve 50 can be suitably ensured when a high potential is applied to the paint, and the advantage is that accuracy can be maintained and manufacturing costs can be reduced. However, the four-way switching valve 50 is enclosed in a container 72 made of an insulating material, and this container 72 is enclosed in a cover member 74 made of an insulating material. container 72
The creepage distance L where the cover member 74 is in direct contact with the
(approximately 200 mm). As a result, even if a high voltage is applied to the four-way switching valve 50 side made of a conductive material, discharge due to current leakage does not occur, and the desired voltage can be maintained to efficiently perform coating work. This has the effect of being able to.

Moreover, since the leakage prevention structure 70 is provided, there is no need to adopt a special structure for preventing electric leakage in the connecting means 80 connected to the container 72, and the manufacturing cost of this connecting means 80 increases. It is possible to prevent this from happening.

Furthermore, even if a conductor such as a robot arm approaches the four-way selector valve 50, no discharge is generated from the four-way selector valve 50. It can be placed inside. As a result, the length of the delivery paths 48a, 48b from the intermediate storage tank 26 to the paint gun 52 can be made as short as possible, and wasteful paint discharged especially when changing the paint color is reduced at once. This has the effect of reducing cleaning time and the amount of cleaning liquid used.

Next, a leakage prevention structure for an electrostatic coating device according to a second embodiment of the present invention will be explained with reference to FIG. Note that the same reference numerals as in the earth leakage prevention structure 70 according to the first embodiment indicate the same components, and detailed explanation thereof will be omitted.

The earth leakage prevention structure 100 of this second embodiment includes a container 102 and a cover member 104, and
Flange portions 102a and 104a are formed on the container 102 and the cover member 104 at portions where they are joined to each other, and an insulating seal member 106 is disposed between the flange portions 102a and 104a. In this case, cover member 1
Creepage distance L1 where 04 and container 102 are in direct contact is
The creepage length is selected to be less than or equal to the required creepage length that can prevent electrical leakage.

According to this second embodiment, the cover member 1
By providing the insulating seal member 106 at the end of the creeping surface where the container 102 and the container 102 are in direct contact with each other, the creepage distance L1 is further reduced. Specifically, -6
When a voltage of 0 kV is applied, if the seal member 106 made of tetrafluoroethylene resin is used, this seal member 1
Since the dielectric breakdown voltage of 06 is about 20 kV/mm, if the sealing surface is 2 mm, it is possible to seal a voltage of 40 kV. Therefore, it is only necessary to secure a creepage distance that can seal the remaining 20 kV of voltage, and in fact, 5
A creepage distance of approximately 0 mm is sufficient. This can be shortened to about 1/4 of the creepage distance of about 200 mm when the insulating seal member 106 is not provided.

In this embodiment, a case has been described in which the earth leakage prevention structure 70 is applied to the four-way switching valve 50, but the present invention is not limited to this. be able to.

[0028]

Effects of the Invention According to the earth leakage prevention structure for electrostatic coating equipment according to the present invention, the following effects can be obtained.

[0029] Since the valves, intermediate storage tanks, and other devices are constructed of conductive materials, desired precision and strength can be ensured. The device is covered with a container made of an insulating material and a cover member, and the creepage distance formed by the container and the cover member is selected to be greater than the necessary creepage length that can prevent electric leakage. Even if a high voltage is applied to the circuit, it is possible to effectively prevent electrical leakage. This eliminates the need to separate equipment made from conductive materials from paint booths, etc., making it possible to shorten the paint path as much as possible, and reducing wasted paint, cleaning time, and cleaning fluid when changing colors. .

Furthermore, according to the present invention, even if the creepage distance between the container and the cover member is selected to be less than the necessary creepage length that can prevent electric leakage, the sealing effect of the insulating seal member It is possible to effectively prevent electrical leakage from occurring when high voltage is applied.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of a leakage prevention structure of an electrostatic coating device according to a first embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of a coating apparatus incorporating the earth leakage prevention structure.

FIG. 3 is a longitudinal cross-sectional view of a leakage prevention structure of an electrostatic coating device according to a second embodiment of the present invention.

[Explanation of symbols]

10...Painting device 12...Color change valve mechanism 26...Intermediate storage tank 48a, 48b...Sending path 50...Four-way switching valve 52...painting gun 70…Earth leakage prevention structure 72...Container 74...Cover member 76, 78...Aisle 80...Connection means 100...Earth leakage prevention structure 102...Container 104...Cover member 102a, 104a...flange part 106...Insulating seal member

Claims (2)

[Claims] Claim 1: A device made of a conductive material, such as a valve or an intermediate storage tank, used in a coating device that performs electrostatic painting by applying a voltage to a conductive paint, and a device that includes the device and can freely communicate with the device. A container made of an insulating material in which a paint passage is formed, and a cover member enclosing the container, and a creepage distance between the container and the cover member is selected to be greater than or equal to a necessary creepage length that can prevent electrical leakage. An earth leakage prevention structure for electrostatic painting equipment. 2. Devices made of a conductive material, such as valves and intermediate storage tanks, used in a coating device that performs electrostatic painting by applying a voltage to conductive paint; A container made of an insulating material in which a paint passage is formed, a cover member enclosing the container, and an insulating seal member disposed between the container and the cover member, and configured by the container and the cover member. An earth leakage prevention structure for electrostatic coating equipment, characterized in that the creepage distance is selected to be less than or equal to the required creepage length that can prevent earth leakage.