JP2002310844A - Paint leakage detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a paint leakage detector capable of correctly and accurately detecting paint leakage without being affected by electric noise from a voltage application means. SOLUTION: Variation of internal pressure of an air hose 51 with one end sealed with a member 52 of solvent broken matter is detected by a pressure sensor 53.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paint leak detecting device for detecting paint leak, and more particularly to a paint leak detecting device which is not affected by noise when a high voltage is applied and has high reliability.

[0002]

2. Description of the Related Art Paint leakage from a coating apparatus adversely affects the appearance quality of a product. However, since it is difficult to detect paint leakage occurring inside the coating apparatus from the outside, a paint leakage detection device 1 'that automatically detects paint leakage has been proposed. Japanese Patent Application Laid-Open No. 5-1266671 discloses a paint leakage detection device 1 'for detecting an ON-OFF electric signal generated by contact / separation of the contacts of two contact terminals sandwiching the solvent destructive member 52. I have. The detected electrical signal related to paint leakage reports paint leakage to the outside via a sensor cable 8 wired in the movable arm 3 (see FIG. 6).

[0003]

However, since a high voltage applying cable for applying static electricity to the paint particles is wired inside the moving arm, a high voltage is applied to an electric signal transmitted through the sensor cable. There has been a problem that noise from the application cable is easy to ride and the reliability of the detection result is low.

Further, the detection of paint leakage is triggered by the fact that the contact terminals are eroded by the solvent on the solvent-destructible member. Since the sensor part is always present in the solvent atmosphere (vapor), the solvent destructive member is naturally eroded,
As a result, there is a problem that an erroneous paint leak is detected. Further, although the solvent concentration in the sensor portion (atmosphere) and the amount of paint leakage at the time of the paint leakage accident differ depending on the supply amount of paint, the detection sensitivity cannot be adjusted according to the supply amount of paint. There was a problem.
The present invention has been made in view of such problems of the related art, and has as its object to provide a paint leakage detecting device which is not affected by noise when a high voltage is applied and has high reliability.

[0005]

(1) In order to achieve the above object, according to the first aspect of the present invention, there is provided a moving arm for mounting a coating gun and moving the coating gun with respect to an object to be coated. An apparatus for detecting paint leakage in a coating apparatus provided with a hose for supplying paint to the coating gun together with a solvent, wherein the solvent destructive member destroyed by the solvent leaked from the hose, Pressurizing means for sending compressed gas from the other end of the air hose one end of which is sealed by a member, and pressure detecting means provided at a position separated from the voltage applying means of the coating gun and detecting the internal pressure of the air hose; And a paint leakage detection device having the following. According to the second aspect of the present invention, the pressure detecting means includes a controller for calculating a pressure difference from the internal pressure detected by the pressure detecting means and the pressure of the compressed gas sent from the pressurizing means. An apparatus is provided.

According to the present invention, a pressure detecting means is provided at a position remote from the voltage applying means of the coating gun, and the pressure detecting means has a pressure inside the air hose which is sealed at one end with a solvent destructive member and filled with a compressed gas. The change is measured over time.
At the initial stage of installation, the internal pressure of the air hose is constant because the solvent destructible member seals the air hose. However, when the paint leaks, the solvent destroys the solvent destructible member, so that the air hose is released from the sealed state and the internal pressure of the air hose decreases. The pressure detecting means determines paint leakage based on the change in the internal pressure, and outputs to the outside of the apparatus that paint leakage has occurred.

[0007] Thus, since the sensor cable and the pressure detecting means for processing the electric signal are not disposed near the power applying means, the noise is not received from the power applying means and the reliability of the detection result is improved. A high paint leakage detection device can be provided.

In the present invention, the pressure detecting means may be arranged at a position distant from the voltage applying means so as not to receive noise from the voltage applying means. Further, it may be arranged outside the coating booth of the coating apparatus. The compressed gas includes compressed air and other compressed gases.

The solvent destructible member may be in any state as long as it can seal one end of the air hose, and may be a state in which compressed gas is sent, such as being pressed against one end, enclosing one end, or being sealed. Any condition may be used as long as the internal pressure can be kept constant.

(2) In order to achieve the above object, according to the third aspect of the present invention, when the calculated pressure difference is equal to or greater than a set threshold, the controller warns of paint leakage. A leak detection device is provided. According to the third aspect of the present invention, the threshold value is set according to the supply amount of the paint.

According to the present invention, the threshold value is set in advance, and the controller determines whether or not the pressure difference is equal to or greater than the set threshold value. The setting of the threshold value is preferably set according to the amount of the supplied paint.

When the amount of supplied paint is large (the amount of paint leakage is large) and when the amount of supplied paint is small (the amount of paint leakage is small), the amount of paint leakage and the solvent The breaking amount of the destructible member is also different. That is, when the paint supply amount is large, the solvent-destructible member melts instantaneously when the paint supply amount is large, but when the paint supply amount is small, the solvent-destructible member is destroyed little by little. The shape change amount per contact is small, and the measured internal pressure difference of the air hose is also small. Therefore, the pressure difference suitable for detecting paint leakage when the supply paint is large is different from the pressure difference suitable for detecting paint leakage when the supply paint is small. From such a viewpoint, the threshold value is set according to the amount of the supplied paint.

According to the present invention, the conditions for detection can be adjusted according to the environment in which the solvent destructive member for detecting paint leakage is placed, and a paint leakage detection device with high accuracy can be provided.

(3) In order to achieve the above object, according to the fifth aspect of the present invention, the solvent destructible member is accommodated,
A paint leakage detection device further includes a container having one or more openings. The container preferably has an opening adjusting means for adjusting the size of the opening area of the opening (claim 6). In the present invention, the solvent destructive member is accommodated in a container having an opening. The leaked paint and naturally volatilized solvent pass through the opening and enter the container, destroying the contained solvent-destructible member.

By providing such a container, the solvent destructible member and one end of the air hose can be securely fixed.
Further, since the fixing is easy, the attachment and replacement of the solvent destructible member can be easily performed. Furthermore, since the solvent-destructible member is contained in a container, it can be installed anywhere without considering the destruction by the naturally volatilized solvent, and it must be installed in a place where the solvent concentration is high (where paint leakage easily occurs). Thus, it is possible to provide a highly sensitive paint leakage detection device.

Further, the opening adjusting means adjusts the amount of the solvent volatilized naturally entering the container by adjusting the size of the opening area of the opening. By providing the opening adjusting means, the opening area of the container arranged in an environment where the concentration of the naturally volatilized solvent is high is reduced, and the solvent destructible member is prevented from being destroyed by the naturally volatilized solvent. . In this case, if paint leakage occurs, the paint flows from the small opening, the solvent destructive member is destroyed, and paint leakage is accurately detected.

(4) In order to achieve the above object, according to the invention of claim 7, there is provided a paint leakage detecting device in which the container has a solvent holding portion for holding the solvent.
In the present invention, the solvent holding section is provided in the container. Even if paint leaks and a small amount of solvent enters the container,
The solvent holding section holds the solvent, and the held solvent causes the solvent destructible member in the container to be destroyed.

Thus, even if a small amount of paint leaks, it is possible to accurately detect paint leak, and even if the opening area of the opening is reduced to be installed at a position where the solvent concentration is high. It is possible to provide a paint leakage detection device capable of accurately detecting paint leakage.

[0019]

According to the first and second aspects of the present invention, since no sensor cable or pressure detecting means for processing an electric signal is disposed near the power applying means, noise from the power applying means can be reduced. It is possible to provide a paint leakage detection device with high reliability of the detection result without receiving the paint leakage.

According to the third and fourth aspects of the present invention, the conditions for detection, that is, the threshold value of the internal pressure difference of the air hose can be adjusted in accordance with the environment of the solvent destructive member for detecting paint leakage. And a paint leakage detection device with high reliability.

According to the fifth aspect of the present invention, by providing the container, the fixing between the solvent destructible member and one end of the air hose is ensured. Further, since the fixing is easy, the attachment and replacement of the solvent destructible member can be easily performed. In addition, since the solvent destructible member was stored in the container,
Provide a highly sensitive paint leak detection device that can be installed anywhere without consideration of destruction by naturally volatilized solvents and can be installed in a place with a high solvent concentration (a place where paint leakage is likely to occur). Can be.

According to the sixth aspect of the present invention, by providing the opening adjusting means, the area of the opening of the container placed in an environment where the concentration of the naturally volatilized solvent is high can be reduced, and the naturally volatilized solvent can be reduced. This prevents the solvent destructible member from being destroyed. In this case, if paint leakage occurs, the paint flows from the small opening, the solvent destructive member is destroyed, and paint leakage is accurately detected.

According to the present invention, even if a small amount of paint is leaked, the paint leak can be detected with high accuracy. It is possible to provide a paint leakage detection device that can accurately detect paint leakage even when the size is reduced.

[0024]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a coating device provided with a coating leak detection device of the present embodiment, FIG. 2 is a diagram illustrating an end of an air hose, FIG. 3 is a diagram illustrating an arrangement of a solvent destructive member, and FIG. FIG. 5 is a configuration diagram for explaining the operation of the paint leakage detecting device, and FIG. 5 is a graph showing a change in the volume of the solvent destructive member and a change with time in the air pressure (internal pressure) of the air hose.

First, a coating apparatus 100 provided with a paint leakage detecting apparatus 1 according to the present embodiment will be described with reference to FIG. The coating apparatus 100 includes a movable arm 3 which is connected to a base supported by a booth wall and moves freely, a bracket 21 for a coating gun which is provided at the tip of the movable arm 3 and is rotatable,
And a coating gun 2 locked to a coating gun bracket 21. An electrode 71 for charging paint particles is provided in the coating gun 2, and a voltage application cable 7 for applying a high voltage to the electrode 71 is wired in the moving arm 3. Also, a paint hose 4 for supplying paint to the coating gun 2
And the air hose 51 are also wired in the moving arm 3.

Paint gun 2 or paint gun bracket 21
Is provided with a solvent destructible member 52 for detecting paint leaked from the paint hose 4. An air hose 51 having one end sealed to the solvent destructible member 52
Is connected to a pressure sensor 53 provided outside the painting booth through the inside of the moving arm 3. This pressure sensor 5
3 is set apart from the high voltage application cable 7. Since the high voltage application cable 7 applies the cathode to about -90 V, the influence of noise from the high voltage application cable 7 cannot be avoided. Therefore, the pressure sensor 53
, The electrical signal related to paint leakage is not affected by noise from the high-voltage application cable 7 and erroneous detection can be prevented.

The air hose 51 is filled with a compressed gas as a medium for detecting a change in pressure. As the compressed gas, compressed air or other compressed gas can be used. In this embodiment, compressed air is used.

FIG. 2 shows one end of the air hose 51. One end of the air hose 51 is sealed by a solvent destructible member 52 housed in the container 521 without any gap, and the other end is connected to the pressure sensor 53. The solvent destructible member 52 is housed in a container 521, and is provided with an opening 522 and an opening adjusting means 523 for adjusting the size of the opening area of the opening 522. Also, the container 521
A sponge body 525 for holding a solvent is disposed at the bottom of the slab.

By housing the solvent-destructible member 52 in a container, the solvent-destructible member 52 can be prevented from being exposed to the solvent atmosphere, and the life of the solvent-destructible member 52 can be extended. Further, fixing and replacement with the air hose end portion 51 are facilitated, and the air hose can be arranged at a desired position.

The container 521 is provided with a plurality of openings 522. When the paint leaks, the paint enters through the openings 522 and destroys the solvent destructible member 52. In addition, even during installation, the solvent that has volatilized naturally has the opening 522.
, And the solvent destructible member 52 is spontaneously destroyed. If the solvent concentration (thinner concentration) at the paint leakage detection position is high, the solvent destructive member 52 is naturally destroyed, and the paint leakage is erroneously detected. The opening adjusting means 523 adjusts the amount of the solvent volatilized naturally entering the container 521 by adjusting the size of the opening area of the opening 522.

By providing the opening adjusting means 523, the area of the opening of the container 521 placed in an environment where the concentration of the naturally volatilized solvent is high is reduced, and the solvent destructible member 52 is destroyed by the naturally volatilized solvent. To prevent it from being done. In this case, if paint leakage occurs, the paint flows from the small opening 522, and even if the amount is small, the solvent destructive member 52 is destroyed, and paint leakage is accurately detected. This makes it possible to set detection conditions according to the environment of the field to be detected, prevent erroneous detection, and perform highly accurate detection.

The adjusting mechanism of the opening adjusting means 523 shown in FIG. 2 will be specifically described. At the bottom of the container 521, an opening adjusting means 5 which forms a double structure with the side surface of the container 521
23 are provided. This opening adjusting means 523 is
It is for adjusting the size of the opening area of the opening 522 and has a band-like ring shape surrounding the outer periphery of the container 521. The container 521 has an opening 524 separately from the container 521, and rotates while sliding on the side surface of the container 521. Container 52
1 opening 522 and the opening 5 of the opening adjusting means 523.
24 are arranged at a position where they overlap with each other, and when they are rotated while being slid, the overlapping area of the openings 522 and 524 can be adjusted. Opening 5 indicated by hatching in FIG.
A portion where the opening 22 and the opening 524 overlap each other is an actual opened portion. Further, it is sufficient that the size of the opening area of the opening 522 can be adjusted, and a window that opens and closes may be provided in the opening 522.

The end of the air hose 51 is the solvent destructive member 5
It is sealed so as to be wrapped in 2. The figure shown in the chain line is a figure which illustrates the mode of sealing of the air hose 51. (A) shows a state in which one end of an air hose 51 is wrapped in a solvent destructive member 52, and (b) shows a state in which
1 is a state in which the solvent destructible member 52 is pressed against one end, and (c) is a state in which one end of the air hose 51 is sealed with the solvent destructible member 52. The air hose 51 may be hermetically sealed as long as the internal pressure in the state where the compressed air is sent can be kept constant. Further, in consideration of erroneous detection and deterioration with time, it is preferable that the end of the air hose 51 be as far away from the opening 522 as possible.

Incidentally, this container 521 is made of polytetrafluoroethylene (for example, trade name Teflon) from the viewpoint of solvent resistance, and has a diameter of 10 mm,
It has a cylindrical shape with a height of 15 mm. The inner diameter of the air hose 51 locked to the container 521 is 4 mm. The solvent destructible member 52 has a cylindrical shape with a diameter of 6 mm and a height of 10 mm so as to be accommodated in the container 521, and is made of a foamed resin, such as styrene foam, which is destroyed by a solvent. In addition, four openings 522 having a diameter of 5 mm were provided below the side surface of the container 521, and openings 522 (not shown) having a diameter of 5 mm were provided at the bottom of the container 521.

FIG. 3 is a view for explaining the arrangement of the solvent destructible member 52 in the coating gun bracket 21 of the coating apparatus 100. The solvent destructive member 52 is contained in a container 521. In the paint leak detecting device 1 of the present embodiment, the paint leak can be detected by the solvent volatilized by the paint leak even if the solvent destructive member 52 does not directly touch the solvent. However, paint leakage can be detected. Here, as shown in FIG. 3, it was arranged at the corner of the coating gun bracket 21 of the coating apparatus 100. However, if there is a place where the paint easily accumulates due to the posture of the coating gun 2, it is preferable to dispose the solvent destructive member 52 at the place. It is preferable to dispose the solvent destructive members 52 at a plurality of points from the viewpoint of improving reliability.

The container 521 is fixed to a member provided in the coating apparatus 100, for example, a coating hose 4, a rotary atomizing driving cable, an air hose for an air motor, an air hose for driving a trigger valve of a coating gun, and the like by means of an insulator lock or the like. You. The fixing position is preferably a position where a gap is slightly opened between the bottom of the coating gun bracket 21 and the container 521. This is the opening 52 at the bottom of the container 521.
This is because 2 may be located.

Next, the operation will be described. FIG. 4 (a)
FIG. 3 is a configuration diagram for explaining the operation of the paint leakage detection device 1. The paint detecting device 1 is provided along with the above-described coating device 100. The air pump 54 supplies compressed air to the air hose 51.
, The internal pressure of the sealed air hose 51 becomes constant. When hose puncture occurs in the paint hose 4 and paint leakage occurs, the solvent in which the paint has directly or volatilized enters the container 521 from the opening 522 of the container 521, and the solvent destructive member 52 contained in the container 521 is contained. Destroy. As a result, the air hose 51 is released from the sealed state, and the internal pressure of the air hose 51 decreases. The change in the internal pressure of the air hose 51 is detected by the pressure sensor 53. The change in the internal pressure is the difference between the pressure of the compressed air supplied by the air pump 54 and the actually measured internal pressure of the air hose 51. When this pressure difference exceeds a preset threshold, the pressure sensor 53 determines paint leakage.
The set threshold value will be described later. When the pressure sensor 52 determines paint leakage based on the pressure change,
The paint leakage signal is transmitted to the control means 6 for managing the overall painting. The control means 6 stops the paint pump 41, which is an external device, based on the paint leak signal to prevent the damage caused by paint leak from increasing. This control is shown in a block diagram in FIG. According to the experiment on the pressure change, when the solvent destructible member 52 is melted and the end of the air hose 51 is released after the compressed air of about 0.15 Mp is sent, the internal pressure of the air hose 51 is reduced from 0.15 MPa to 0. 0.05MPa.

The threshold value of the pressure difference in paint leakage judgment will be described. When the amount of supplied paint is large (the amount of paint leakage is large) and when the amount of supplied paint is small (the amount of paint leakage is small), the amount of paint leakage when paint leakage occurs and the solvent destruction member 52 Also have different destruction amounts. That is, the solvent-destructible member is instantaneously melted in the case of paint leakage when the paint supply amount is large, whereas the solvent-destructible member is slightly destroyed in paint leakage when the paint supply amount is small.

From this, it can be said that, in the case of paint leakage when the paint supply amount is small, the shape change per unit time is small, and the measured internal pressure difference of the air hose is also small. Therefore, the pressure difference suitable for detecting paint leakage when the supply paint is large is different from the pressure difference suitable for detecting paint leakage when the supply paint is small. From such a viewpoint, the threshold value is set according to the amount of the supplied paint.

This will be described specifically with reference to the graph shown in FIG. FIG. 5 is a graph showing a change in the volume of the solvent destructible member 52 and a change in the air pressure (internal pressure) of the air hose 51 with time. Both a shown by a two-dot chain line and b shown by a solid line are changes in pressure (difference) due to spontaneous destruction of the solvent destructible member 52, and indicated by a chain line are solvent destruction when paint leakage occurs. This is a pressure (difference) change due to the destruction of the conductive member 52. Further, a indicates a change in the pressure (difference) in a small amount of the supply paint, that is, the pressure (difference) in a low-concentration solvent atmosphere. Difference) There is a change. As shown in FIG. 5, b (high concentration solvent atmosphere)
(Low concentration solvent atmosphere) changes greatly. This is because the destruction of the solvent destructive member 52 occurs more severely in a highly concentrated solvent atmosphere.

Detection level 1 and detection level 2 shown in FIG.
Is a pressure (difference) threshold candidate for judging paint leakage. If the naturally occurring pressure drop in the air hose 51 falls below the detection level 1 or 2, erroneous detection (timing D) occurs. Therefore, the solvent destructible member 52 should be replaced at a time earlier than this.

When paint leakage occurs (timing A),
The pressure drops sharply and the pressure (difference) increases sharply. A dashed line C indicates a pressure drop due to paint leakage occurring at the timing A. If paint leakage occurs, paint loss increases with time, so it is preferable to detect paint leakage as soon as possible. Paint leakage detection timing B, C
Of these, the timing B is more appropriate in that the paint leakage is detected earlier. However, assuming that the threshold is detection level 1,
If the erroneous detection timing D is too short (high concentration solvent atmosphere), erroneous detection will occur frequently. Therefore, the threshold is set in consideration of both the viewpoint of detection accuracy and the viewpoint of erroneous detection. In the present embodiment, the detection level 2 is set as the threshold. Although this experimental data is created based on the value of the internal pressure of the air hose 51, it is further converted into a pressure difference between the pressure of the compressed air supplied based on this value and the actually measured internal pressure and supplied. The relationship between the pressure change and the threshold value for each paint amount may be arranged. Thus, it is possible to set a detection accuracy in accordance with the amount of the supplied paint (solvent concentration in the solvent atmosphere), suppress occurrence of erroneous detection, and provide a paint leakage detection device with high accuracy and less erroneous detection.

The embodiments described above are described for the purpose of facilitating the understanding of the present invention, but not for limiting the present invention. Therefore, each element and each numerical value disclosed in the above embodiment are:
It is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

[Brief description of the drawings]

FIG. 1 is a view showing a coating apparatus provided with a coating leak detection device of the present embodiment.

FIG. 2 is a diagram illustrating an end of an air hose.

FIG. 3 is a view for explaining an arrangement of a solvent destructive member.

FIG. 4 is a configuration diagram for explaining the operation of the paint leakage detection device.

FIG. 5 is a graph showing a change in the volume of the solvent destructible member and a change with time in the air pressure (internal pressure) of the air hose.

FIG. 6 is a diagram illustrating a conventional paint leakage detection device using an electric signal.

[Explanation of symbols]

100, 100 '... Coating device 1, 1' ... Paint leak detection device 2: Coating gun 21: Bracket for paint gun, joint 3 ... Moving arm, robot arm, reciprocator arm 4: Paint hose 41: Paint supply pump , A paint pump, a gear pump 5 ... detecting means 51 ... air hose 52 ... solvent destructive member 521 ... container 522 ... opening 523 ... opening adjusting means 524 ... opening of opening adjusting means 525 ... sponge body (solvent holding section) 53: pressure sensor (pressure detecting means) 531: controller 54: air pump (pressurizing means) 6: paint supply control device 7: high-voltage applying cable (voltage applying means) 71: electrode 8: sensor cable

Continuation of the front page (72) Inventor Manabu Wada 2nd Takaracho, Kanagawa-ku, Yokohama-shi, Kanagawa Prefecture F-term (reference) 2G067 AA17 BB34 CC01 DD02 EE09 4D073 AA01 BB03 CA07 CB02 DA05 DD40 4F033 QA01 QB03X QB16X QD02 Q06 QK08X QK11X QK22X QK27X 4F034 AA03 BA22 BA32 BB21 DA22

Claims (7)

[Claims] 1. A coating apparatus having a hose for supplying a paint and a solvent to a paint gun inside a moving arm to which the paint gun is attached and moving the paint gun relative to an object to be coated, to detect paint leakage. An apparatus, comprising: a solvent destructible member that is destroyed by a solvent leaked from the hose; pressurizing means for sending compressed gas from the other end of an air hose one end of which is sealed with the solvent destructible member; A paint leak detecting device, provided at a position distant from the voltage applying means of the gun, and comprising pressure detecting means for detecting the internal pressure of the air hose. 2. A paint leakage detecting device according to claim 1, wherein said pressure detecting means has a controller for calculating a pressure difference from an internal pressure detected by said pressure detecting means and a pressure of a compressed gas sent from said pressurizing means. apparatus. 3. The paint leak detecting device according to claim 2, wherein the controller warns of paint leak when the calculated pressure difference is equal to or larger than a set threshold value. 4. The paint leakage detecting device according to claim 3, wherein said threshold value is set in accordance with a supply amount of said paint. 5. The paint leakage detecting device according to claim 1, further comprising a container which accommodates said solvent destructive member and has one or a plurality of openings. 6. The paint leakage detecting device according to claim 5, wherein said container has an opening adjusting means for adjusting the size of the opening area of said opening. 7. A paint leakage detecting device according to claim 5, wherein said container has a solvent holding portion for holding said solvent.