JP2002143726A - Method for detecting abnormality of electrostatic coating apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for detecting abnormality of an electrostatic coating apparatus which can prevent erroneous detection of a spark abnormality caused by an electric power leak. SOLUTION: The method for detecting abnormality of an electrostatic coating apparatus which detects abnormality of the electrostatic coating apparatus having a coating spray device 1, a coating feed device 2 and a power supply device 3, is characterized by having a power supply measuring process for measuring a power supply flowing in a power supply circuit 32, a leak power measuring process for measuring a leak power flowing in an earth circuit 24 and an abnormality detecting process detecting spark abnormality by the supply power and the leak power. The method prevents the erroneous detection of the abnormality caused by a power leaking to a coating material side since the spark abnormality is detected by measuring the supply power and the leak power.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for detecting an abnormality in an electrostatic coating apparatus for detecting a spark abnormality in the electrostatic coating apparatus.

[0002]

2. Description of the Related Art Paints used in automobiles and the like are expensive, and therefore are coated by electrostatic coating in order to suppress the occurrence of loss.

[0003] In general, electrostatic coating means that a grounded object is used as an anode, and a paint spraying device for spraying paint in a mist is used as a cathode to apply a negative high voltage to create an electrostatic field between the two electrodes. ,
This is a coating method in which the sprayed paint particles are negatively charged, and the paint is efficiently attached to the object to be coated, which is the opposite pole. In addition, since the electrostatic coating requires a high voltage, it is performed using an electrostatic coating device.

However, when performing electrostatic coating,
If the paint spraying device having a high voltage is too close to the object to be coated, there is a problem that a spark abnormality occurs in which a spark is generated between the two. Specifically, when the paint spraying device and the object to be coated are too close to each other, a current flows through a highly conductive portion between the paint spraying device and the object to be coated, and a spark has been generated. Here, when a spark occurs, the atomized paint ignites, and a fire occurs.

In order to suppress the occurrence of this spark abnormality,
The conventional electrostatic coating device measures the power supplied to the paint spraying device, and when an abnormality is detected, shuts off the power supplied to the paint spraying device to prevent the occurrence of a spark. That is, when a spark abnormality occurs, an electric current easily flows from the paint spraying device to the object to be coated, and excessive power flows from the power supply unit to the paint spraying device. For this reason, the conventional electrostatic coating apparatus measures the electric power flowing through the paint spraying apparatus, and detects an abnormal spark when excessive electric power is supplied.

However, in such a method of measuring the power supplied to the paint spraying device, an increase in the amount of power supply caused by a leak current flowing from the paint spraying device to the paint applied is also detected as a spark abnormality. Had the problem that

More specifically, a metallic paint in which aluminum flakes are dispersed is used as a paint for vehicles in recent years, and since such a metallic paint and the like easily leaks electric power from a paint spray device to the paint side. It is. That is, a state in which the dispersed aluminum flakes are partially aggregated in the pipeline for supplying the paint to the paint spraying device occurs, and the electric power applied to the electrode body flows along the partial aggregation. As a result, the amount of electric power required for the paint spraying device increases, and excessive power is supplied to the paint spraying device, so that a spark abnormality is detected.

[0008] In the electrostatic coating device, a ground circuit for connecting a pipe line for supplying paint to a ground potential is formed, so that leak power from the paint spray device is discharged and leak power is supplied to the paint supply device. It does not flow.

In addition, when the painting operation is stopped due to erroneous detection, when a metallic paint is used as the paint,
Because aluminum flakes precipitate in the paint supply line,
There is also a problem that the pipe for supplying the paint must be cleaned, which increases the cost.

[0010]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a method for detecting an abnormality of an electrostatic coating apparatus which can prevent erroneous detection of a spark abnormality due to leakage power. .

[0011]

Means for Solving the Problems In order to solve the above-mentioned problems, the present inventors have repeatedly studied a method for detecting an abnormality in an electrostatic coating apparatus, and as a result, the electric power flowing to the ground circuit and the electric power supplied to the paint spraying apparatus are obtained. It has been found that a detection method for detecting a spark abnormality from electric power can solve the above problem.

That is, a method of detecting an abnormality in an electrostatic coating apparatus according to the present invention is directed to a paint spraying apparatus having a paint spray port for atomizing and spraying paint and an electrode body for applying a charge to the atomized paint. A paint supply pipe through which the paint communicated with the paint ejection port passes, and a paint supply unit for supplying paint to the paint spraying device via the paint supply pipe, one of which is connected to the pipe and the other is ground potential. An electrostatic circuit having a paint supply device having a ground circuit connected to the power supply device for supplying power to the electrode body, and a power supply circuit connecting the supply power supply and the electrode body. An abnormality detection method for an electrostatic coating apparatus that detects a spark abnormality of a coating apparatus, a supply power measurement step of measuring supply power flowing through a power supply circuit, and a leakage power measurement step of measuring leakage power flowing through an earth circuit. Power supply and resources And having an abnormality detection step of detecting a spark abnormality and click power, the.

[0013] The abnormality detecting method of the electrostatic coating apparatus according to the present invention comprises:
Since the supply power and the leak power are measured and the spark abnormality is detected from both powers, erroneous detection of the abnormality due to the power leaked to the paint side can be suppressed. As a result, the stoppage of the operation of the electrostatic coating device is suppressed, and the operation efficiency is improved.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An abnormality detection method for an electrostatic coating device according to the present invention is a detection method for detecting a spark abnormality in an electrostatic coating device having a paint spraying device, a paint supply device, and a power supply device. is there.

The paint spraying device is a device having a paint spray port for atomizing and spraying paint, and an electrode body for applying a charge to the atomized paint. That is, the paint spraying device is
This is a device that atomizes paint and imparts electric charge to the atomized paint.

The paint spraying apparatus is not particularly limited as long as it sprays the paint and applies electric charges to the sprayed paint. That is, a paint spraying device used in a conventional electrostatic coating device can be used.

The paint spraying device can be roughly classified into three types according to the method of atomizing the paint, and any device using any of the methods may be used. That is, according to the method of atomizing the paint, it is roughly classified into air atomization electrostatic coating, airless electrostatic coating, and rotary atomization electrostatic coating.

In the air atomization electrostatic coating, the paint is atomized by air, and a high voltage is applied to an electrode body composed of corona pins, whereby the atomized paint particles become charged. Air atomization electrostatic coating is the atomization of paint (fine particles)
And good coating surface quality can be obtained. The air atomization electrostatic coating can be used in a top coating (finish coating) process of an automobile.

The airless electrostatic coating is a coating method similar to the air atomizing electrostatic coating except that the atomization of the paint is performed by increasing the ejection pressure of the paint. In the airless electrostatic coating, the repulsion of the paint on the surface to be coated is small. For this reason, it is used in the intermediate coating process of automobiles and the like.

The rotary atomizing electrostatic coating is a coating method in which a coating material is mechanically and electrostatically atomized and applied. This rotary atomizing electrostatic coating is a coating method with a high coating efficiency of paint,
Used in the middle coat process of automobiles. As a paint spraying device using the rotary atomizing electrostatic coating, for example, a bell coating device can be mentioned. Figure 2 shows the configuration of the bell coating device
It was shown to.

FIG. 2 shows that the bell coating apparatus has a substantially conical coating bell 1 having a hollow interior and an open bottom.
1, a paint jet nozzle 12 from which the paint opened inside the paint bell 11 is ejected, and an inner peripheral surface of the paint bell 11 which is provided coaxially with the paint bell 11 while extending in a direction perpendicular to the axial direction of the paint bell 11. Electrode body 1 made of a disc that does not abut
3, a rotating unit 16 that rotates the coating bell 11 and the electrode body 13 around the conical shaft of the coating bell 11 as a rotation axis,
And a booster 14 that is electrically connected to the electrode body 13 and supplies a high voltage to the electrode body 13. Further, the paint spraying device 1 is provided with an air supply nozzle 15 for supplying air into the painting bell 11.

The paint supply device includes a paint supply pipe through which the paint communicated with the paint ejection port passes, a paint supply unit that supplies the paint to the paint spraying device via the paint supply pipe, and one of the pipes. And the other is connected to the ground potential. That is, the paint supply device is a device that supplies paint to the paint spray device. Also,
The ground circuit is provided to prevent the electric charge of the electrode body of the paint spray device from flowing to the paint supply device side through the paint supply pipe and the paint in the pipe.

The paint supply device is not particularly limited as long as it supplies paint to the paint spraying device. That is, a paint supply device used in a conventional electrostatic coating device can be used.

The paint supply device includes, for example, a paint tank for holding a paint, a paint supply pipe having one end opened into the paint held in the paint tank and the other end communicating with a paint outlet of the paint spraying device. And a pump for supplying the paint held in the paint tank through the paint supply pipe.

The power supply device is a device having a power supply for supplying power to the electrode body and a power supply circuit for connecting the power supply and the electrode body. That is, the power supply device
This is a device for supplying electric power for giving electric charge to the atomized paint to the electrode body.

The power supply device is not particularly limited as long as it supplies power to the electrode body. That is, a power supply device used in a conventional electrostatic coating device can be used.

[0027] The abnormality detecting method of the electrostatic coating apparatus of the present invention is as follows.
This is a detection method including a supply power measurement step, a leak power measurement step, and an abnormality detection step.

The supplied power measuring step is a step of measuring the supplied power flowing through the power supply circuit. That is, by measuring the supply power flowing through the power supply circuit, the power supplied from the supply power to the electrode body of the paint spraying device can be obtained.

The leak power measuring step is a step of measuring the leak power flowing through the earth circuit. That is, by measuring the leak power flowing through the ground circuit, the leak power flowing to the paint supply device via the paint can be obtained.

The abnormality detecting step is a step of detecting a spark abnormality from the supplied electric power and the leak electric power. That is, the abnormality detecting step is a step of calculating the electric power supplied to the paint from the electrode body of the paint spraying device from the supplied electric power and the leak electric power, and detecting a spark abnormality.

The abnormality detecting step is preferably a step of obtaining a power difference between the supplied power and the leak power and detecting a spark abnormality from the power difference. That is, the power difference between the supplied power and the leak power is determined, and when the power difference exceeds a predetermined power range amount, it is determined that the supplied power has flowed from the paint spraying device to the object to be coated, and detected as a spark abnormality. It is a process.

More specifically, in a state where a normal spark abnormality has not occurred, even if the supply power increases, the leak power increases similarly to the supply power. That is, in a state where no spark abnormality has occurred, an increase in the supplied power flows to the ground circuit. As a result, the power difference between the supplied power and the leak power falls within a certain range.

Further, in the state where the spark abnormality occurs, the supply power increases, but the leakage power does not increase. That is, in the state where spark abnormality occurs,
The supplied power flows from the paint spraying device to the object to be coated, and the measured value of the supplied power increases. However,
Since electric power flows from the paint spraying device to the object to be coated, there is no increase in leakage power. As a result, when a spark abnormality occurs, the power difference between the supplied power and the leak power increases.

As described above, the abnormality detection step detects a spark abnormality when the power difference becomes large and exceeds a predetermined range.

In the abnormality detecting step, the predetermined power range in which the power difference is compared cannot be determined unconditionally because it differs depending on conditions such as the type of paint used and the type of electrostatic coating device.

It is preferable to have an abnormality transmitting step of transmitting an abnormal signal when a spark abnormality is detected. By having the abnormality transmission step, occurrence of spark abnormality can be suppressed. That is, it is possible to suppress the supply of the power to be supplied to the electrode body in response to the abnormal signal transmitted in the abnormality transmitting step, and it is possible to suppress the occurrence of spark.

In the supplied power detecting step and the leaked power detecting step, it is preferable to measure current values of the supplied power and the leaked power. Since the electrostatic coating is performed by applying a high voltage to the electrode body, measuring the voltage value of the supplied power and the leak power increases the error, so that the current value that can be measured stably should be measured. Can be.

In the electrostatic coating apparatus for detecting a spark abnormality by the abnormality detecting method of the present invention, the electrostatic coating is performed in a state where the object to be coated is connected to the ground potential. That is, when the electrostatic coating is performed, the electrode body has a high potential to impart a charge to the atomized paint. Further, since the object to be coated is connected to the ground potential, an electrostatic field is generated between the electrode body and the object to be coated, and the paint having electric charge is washed by the object to be coated, and the surface of the object to be coated is Coating is performed with adhesion.

Further, the paint applied by the electrostatic coating apparatus for detecting spark abnormality by the abnormality detection method of the present invention is not particularly limited. That is, the paint used for painting by the conventional electrostatic painting apparatus can be used.

As an example of an electrostatic coating apparatus using the method for detecting an abnormality of the electrostatic coating apparatus of the present invention, a power supply circuit is used in an electrostatic coating apparatus having a paint spraying device, a paint supply device, and a power supply device. And an electrostatic coating device in which a supply power measuring device is provided in a ground circuit and a leak power measuring device is provided in a ground circuit, and the supply power measuring device and the leak power measuring device are connected by an arithmetic device. This electrostatic coating apparatus detects a spark abnormality in a connected arithmetic unit from the electric power value measured by each electric power measuring apparatus.

The abnormality detecting method of the electrostatic coating apparatus according to the present invention comprises:
Since the supply power and the leak power are measured, and the spark power is detected by comparing the two powers, erroneous detection of the abnormality due to the power leaked to the paint side can be suppressed. As a result, stoppage of the operation of the electrostatic coating apparatus due to erroneous detection is suppressed, and the operation efficiency is improved.

[0042]

The present invention will be described below with reference to examples.

(Embodiment) An electrostatic coating apparatus was prepared as an embodiment of the present invention. The configuration of this device is shown in FIG. FIG. 1 shows a state in which the body of an automobile is electrostatically coated using the electrostatic coating apparatus of the embodiment.

The electrostatic coating device of the embodiment is a paint spraying device 1
Paint supply device 2, power supply device 3, supply power measurement device 41, leak power measurement device 42, arithmetic device 4
3).

The paint spraying apparatus 1 has a coating bell 11 having a hollow interior and a substantially conical shape with an open bottom surface for atomizing the paint, and a paint jet for spraying the paint opened inside the coating bell 11. A nozzle 12, an electrode body 13 formed of a disk that extends in a direction perpendicular to the axial direction of the coating bell 11 and is provided coaxially with the coating bell 11 and does not contact the inner peripheral surface of the coating bell 11, and a cone of the coating bell 11. Rotating unit 1 that rotates coating bell 11 and electrode body 13 about the axis of the shape as a rotation axis
6 and a booster 14 electrically connected to the electrode body 13 and supplying a high voltage to the electrode body 13. Further, the paint spraying device 1 is provided with an air supply nozzle 15 for supplying air into the painting bell 11. Here, the detailed configuration of the paint spraying device 1 is shown in FIG. FIG. 2A shows the configuration of the paint spraying apparatus 1 and FIG.
(B) is a diagram showing a state where the painting bell 11 is viewed from the opening.

The paint supply device 2 includes a tank 21 for storing paint, a paint pipe 22 having one end opened to the bottom of the tank 21 and the other end communicating with the paint jet nozzle 12, and a paint pipe formed in the paint pipe 22. This is a device having a pump 23 for supplying the paint spray device 1 from the tank 21 and an earth circuit 24 for connecting the paint pipe 22 to a ground potential.

The power supply device 3 is a device having a power supply 31 capable of supplying a desired amount of power, and a power supply circuit 32 for electrically connecting the power supply 31 and the booster 14.

The supply power measuring device 41 is an ammeter provided in the power supply circuit 32.

The leak power measuring device 42 is connected to the earth circuit 2
It is an ammeter made in 4.

The arithmetic unit 43 is connected to the supplied power measuring device 41 and the leaked power measuring device 42, obtains a current difference between the supplied power current (Ia) and the leaked power current (Ib), and calculates the current difference and a predetermined value. This is a device for comparing with a current value range.

(Electrostatic Coating) The electrostatic coating was performed on the body 5 of the automobile using the electrostatic coating apparatus of the embodiment.

The body 5 of the car to be painted was placed on a trolley 51 connected to ground potential. In addition, the paint spraying device 1 was arranged in a state facing the surface of the body 5 of the automobile.

First, the rotating unit 16 is operated to apply the paint bell 1
1 and the electrode body 13 are rotated. The pump 22 is operated while the paint bell 11 and the electrode body 13 are rotated, and paint is supplied from the paint tank 21 into the paint bell 11. The paint supplied into the painting bell 11 is
Move to the opening of the painting bell 11 along the inner peripheral surface of the
The particles are atomized and sprayed at the opening by the centrifugal force of the rotation of the coating bell 11. At this time, air is supplied from the air supply nozzle 15 into the paint bell 11 in order to prevent the inside of the paint bell 11 from becoming low pressure due to the rotation of the paint bell 11.

Subsequently, while the paint is being sprayed from the paint bell 11, the power supply 31 of the power supply device 3 is operated to apply a negative potential to the electrode body 13. The electrode body 13
A negative potential is applied to the paint particles atomized by the paint bell 11.

When power is supplied to the electrode body 13, an electrostatic field is formed between the electrode body 13 and the body 5 connected to the ground potential.
The paint moves toward the body 5 by the electrostatic force that forms the electrostatic field. The paint having a negative potential is the body 5
, The negative potential moves to the ground potential connected to the body 5 (Ic), so that the paint adheres to the body 5.

(Detection of Spark Abnormality) The electrostatic coating apparatus of the embodiment was operated, the current was measured by the current measuring devices 41 and 42, and the arithmetic unit 43 detected the spark abnormality.
Here, the electrostatic coating apparatus was operated in three states: a state in which electrostatic coating was performed in a stable state, a state in which supply power increased due to an increase in leak power, and a state in which a spark abnormality occurred. .

FIG. 3A shows the current (Ia) of the supplied power measured by the supplied power measuring device 41 during the electrostatic coating, and FIG. 3A shows the current (Ib) of the leaked power measured by the leaked power measuring device 42. FIG. 3B shows the result of detection of a spark abnormality by the arithmetic unit 43 in FIG. Note that FIG.
The spark abnormality in (c) is indicated as an abnormal bit.

As shown in FIG. 3, when the supply current (Ia) has a stable peak in the steady state, the measured peak of the leak power current (Ib) is also stable. At this time,
The arithmetic device calculates the current difference between the supply power current (Ia) and the leak power current (Ib), and compares this current difference with a predetermined current value range. In this steady state, since the current difference is within the predetermined current value range, it is not detected as abnormal.

When a power leak occurs on the side of the paint supply device, the current (Ia) of the supplied power increases. As the current (Ia) of the supplied power increases, the current (Ib) of the leak power also increases. For this reason, since the current difference between the supply power current (Ia) and the leak power current (Ib) is within the predetermined current value range, it is not detected as abnormal.

Further, when a spark abnormality occurs,
The current (Ia) of the supplied power is increasing. When a spark abnormality occurs, an excessive current flows to the body side, and the current (Ib) of the leak power decreases. For this reason,
The current difference between the supply power current (Ia) and the leak power current (Ib) becomes excessive, exceeding a predetermined current value range, and is detected as an abnormal bit.

As described above, the electrostatic coating apparatus according to the embodiment using the abnormality detection method of the present invention does not detect an increase in supply power caused by leakage of power to the paint supply apparatus as a spark abnormality. . Accordingly, the electrostatic coating apparatus according to the embodiment can detect a spark abnormality in which erroneous detection due to an increase in leak power is suppressed.

[0062]

According to the method for detecting an abnormality of an electrostatic coating apparatus of the present invention, a power supply and a leakage power are measured, and a spark abnormality is detected from both powers. The erroneous detection of spark abnormality due to is suppressed. As a result, the stop of the operation of the electrostatic coating device due to the erroneous detection of the spark abnormality is suppressed, and the reduction in the efficiency of the coating operation by the coating device is suppressed.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a configuration of an electrostatic coating apparatus according to an embodiment.

FIG. 2 is a diagram showing a configuration of a bell coating device.

FIG. 3 is a diagram illustrating a measurement result of a current in a power measurement device and detection of an abnormal bit in a calculation device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Paint spraying device 11 ... Paint bell 12 ...
Paint spray nozzle 13 ... Electrode body 14 ... Pressure booster 15 ...
Air supply nozzle 2 ... Paint supply device 21 ... Tank 22 ...
Paint pipe 23 Pump 24 Earth circuit 3 Power supply device 31 Power supply 32
Power supply circuit 41: Supply power measurement device 42: Leakage power measurement device 43: Calculation device 5: Body

Claims (4)

[Claims] 1. A paint jet port for atomizing and jetting paint,
A paint spraying device having an electrode body for imparting electric charge to the atomized paint, a paint supply pipe through which the paint communicates with the paint outlet, and a paint supply pipe. A paint supply unit having a paint supply unit for supplying the paint to the paint spraying device, a ground circuit having one connected to the pipeline and the other connected to a ground potential, and supplies power to the electrode body. Power supply,
A power supply device having a power supply circuit for connecting the supply power source and the electrode body, and a method of detecting a spark abnormality of the electrostatic coating device having: A supply power measuring step of measuring a flowing supply power; a leak power measurement step of measuring a leak power flowing through the ground circuit; and an abnormality detection step of detecting a spark abnormality from the supply power and the leakage power. A method for detecting an abnormality of an electrostatic coating apparatus, characterized by comprising: 2. The method for detecting an abnormality in an electrostatic coating apparatus according to claim 1, wherein said abnormality detecting step is a step of obtaining a power difference between said supply power and said ground power and detecting a spark abnormality from said power difference. . 3. The abnormality detecting method for an electrostatic coating apparatus according to claim 1, further comprising an abnormality transmitting step of transmitting an abnormality signal when the spark abnormality is detected in the first period. 4. The method according to claim 1, wherein the supply power detection step and the leak power detection step measure current values of the supply power and the leak power.