JPH06323743A - Method and apparatus for sensing conveying malfunction of tunnel furnace - Google Patents

Abstract

PURPOSE:To provide a method and an apparatus for sensing a conveying malfunction of a tunnel furnace in which the malfunction in the furnace can be exactly and rapidly sensed by collecting a conveying state of a base plate, a material to be burned, etc., as images. CONSTITUTION:A method for sensing a conveying malfunction of a tunnel furnace comprises the steps of monitoring a base plate and/or a material to be treated moving in the furnace out of the furnace by a CCD camera, and sensing a variation or a speed change of an image pattern of the plate or/and the material to be treated. An apparatus for sensing a conveying malfunction of a tunnel furnace comprises a CCD camera 8 for falling a conveying state of a base plate 5 or/and a material 4 to be treated in the furnace out of the furnace in a visual field, an image processor 9 for synthesizing obtained image, and an ITV monitor 10 for imaging the treating image to be coupled.

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 abnormal transport of a base plate in a pusher type tunnel furnace, and a device therefor.

[0002]

2. Description of the Related Art In a pusher type tunnel furnace, as shown in FIG. 8, a bed plate 5 having an object to be fired 4 mounted on a hearth track 3 of a tunnel type furnace body 2 equipped with a plurality of heating elements 1 vertically is provided. It is an industrial electric furnace having a mechanism in which the material to be fired 4 is sequentially fed by the pusher of the transfer device 6 and is continuously heat-treated in the process of being transferred in the furnace. When the bed plate 5 is normally moving on the hearth track 3 during the operation of the furnace, as shown in FIG.
Are conveyed in an aligned state, but sometimes the bed plate 5 derails the hearth track 3 and stops.

When one base plate stops, as shown in FIG. 10, the base plates float up between the base plates and the subsequent base plates that are press-fitted by the pusher, which causes an abnormal conveyance of the base plates. Such conveyance abnormalities are mainly caused by damage or deformation of the base plate, mixing of foreign matters, dropping of the bowl or the object to be fired, and when this phenomenon occurs, the base plate, the vessel, the object to be fired Etc., and in the worst case damages the furnace wall, leading to a major accident. Therefore, a person skilled in the art calls the above-mentioned abnormalities in the furnace as push-up of the base plate, and aims at safe operation of the furnace by early detection.

Conventionally, as a means for mechanically detecting a conveyance abnormality in the tunnel furnace, a method is known in which the pressure of the pusher is measured with a load meter and the abnormality is detected by the variation of the load. However, in this method, since the pusher pressure changes with changes in the load of the material to be burned and wear of the base plate or hearth track over time, it is not possible to always accurately detect abnormal conveyance. It has not been put to practical use due to the problem that the material to be fired and the furnace wall have already been damaged when the pressure change is detected.

As an alternative to this, a light receiver is provided on one side of the opening of the tunnel furnace, and a light receiver operatively connected to the pusher is provided on the other side of the tunnel furnace, so that the laser beam that travels linearly in the furnace is interrupted and the pusher is intermittently operated. Electric furnace equipped with a safety device with a mechanism to stop the feeding (Jitsuko Sho 56-50393), the end of the detection rod is brought into contact with the tip of the base plate group at the tunnel furnace exit, and the follow-up motion of the detection rod is captured by the detection sensor. The base plate thrust detection device has a mechanism for detecting the thrust, fluctuation of the base plate predetermined position, speed, etc.
No. 84) is proposed.

[0006]

However, in the former means using a laser beam, it is difficult to match the light emitting portion and the light receiving portion of the laser beam, and in the long tunnel furnace, there is a problem that the laser beam is difficult to go straight. On the other hand, the latter detection rod method has a drawback that the structure of the transfer device is complicated.

The present invention has been developed in view of the above circumstances, and its purpose is to detect abnormal transport in a furnace by capturing an image of the transport state of the base plate and / or the object to be fired in the tunnel furnace. An object of the present invention is to provide a method and an apparatus for detecting anomalies in a tunnel furnace that can accurately and promptly detect the temperature.

[0008]

In order to achieve the above-mentioned object, a method of detecting an abnormal transport of a tunnel furnace according to the present invention is to monitor a base plate or / and an object to be fired moving in the furnace by a CCD camera, A structural feature is that an abnormal transport phenomenon of the base plate in the furnace is detected from a change in the image pattern of the plate and / or the object to be fired or a change in speed.

Monitoring of the base plate and / or the material to be fired by the CCD camera is performed from outside the furnace. As a monitoring method, the CCD camera is directed to the entrance of the tunnel furnace or the exit of the exit into the furnace. Set in a horizontal position with the furnace axis so that the base plate or / and the object to be fired can be seen from the front, or the CCD camera can be directed from the outside of the slit-shaped monitoring hole formed in the side wall of the tunnel furnace toward the furnace. A method is preferably used in which the base plate or the side surface of the object to be fired is set in the visual field by setting it at a position perpendicular to the axis. When the latter method of monitoring through the slit-shaped monitoring hole is adopted, C
If a pattern having an emissivity different from that of the base plate material is formed on the side surface of the base plate monitored by the CD camera at regular intervals, abnormality can be detected by a change in the moving speed.

A transport abnormality detecting apparatus for a tunnel furnace according to the present invention for use in the above-described transport abnormality detecting method keeps a state of transport of a base plate and / or an object to be burned in the tunnel furnace from the outside of the furnace within a field of view. A CCD camera, and an image processing device for synthesizing images obtained by the CCD camera,
The structural feature is that it comprises an ITV monitor that displays a processed image.

[0011]

According to the method and apparatus for detecting abnormal transport of the tunnel furnace according to the present invention, the bed plate or / and the object to be fired which continuously moves in the furnace by the pusher operation are constantly monitored by the CCD camera and taken into view. The image inside is projected on the ITV monitor in real time as a composite image by the image processing device. At this time, the image projected on the ITV monitor shows an image pattern and a change in moving speed that are different from the normal carrying state when a carrying abnormality occurs due to the push-up of the base plate or the like, so the image pattern fluctuation or speed change is monitored. By doing so, it is possible to accurately and promptly detect the conveyance abnormality in the furnace.

Further, the apparatus of the present invention has a C set outside the furnace.
Since the CD camera is simply configured by combining the image processing device and ITV monitor, there is no need to make complicated modifications or equipment to the tunnel furnace, and it is not affected by fluctuations in the pusher pressure of the transfer device. A conveyance abnormality can be accurately detected. In addition, by designing a control circuit that converts the detected abnormal image into an electric signal and connects it to the drive system of the transport device, the operation of the pusher is stopped at the same time as the abnormality is detected, and the base plate, the sagger, the cover It is possible to prevent damage accidents to the burned material and the furnace wall.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below based on the illustrated embodiments. In addition, the same reference numerals are given to the same members common to each drawing.

FIG. 1 is an overall configuration diagram illustrating an apparatus for detecting a conveyance abnormality of a tunnel furnace according to the present invention, in which 7 is a tunnel furnace and 8 is a tunnel furnace.
Is a CCD camera, 9 is an image processing device, and 10 is IT.
It is a V monitor. The overall structure of the tunnel furnace 7 is the same as that of the conventional structure shown in FIG. 8, and the objects to be fired are sequentially transferred in the furnace by the pusher mechanism of the transfer device 6 while being stacked on the base plate. In the example of FIG. 1, the CCD camera 8 is set horizontally on the front surface of the tunnel furnace 7 on the carry-in side, and is connected to the image processing apparatus 9 and the ITV monitor 10. In actual design, ITV monitor 1
0, the image processing device 9, and the computer 17 and the transport device 6 are electrically connected to each other, and the abnormality detection received by the computer 17 is converted into an electric signal to stop the pusher operation.

When the CCD camera 8 is horizontally set at the entrance of the tunnel furnace 7 toward the furnace axis as shown in FIG. 1, the field of view captured is as shown in FIG. 4 are aligned in a normal state, and a pattern in which a constant exit space 11 is always present on the uppermost part of the object 4 to be fired farthest is projected on the ITV monitor 10 as a basic image in a normal transport state. However, once a conveyance abnormality occurs due to the push-up of the base plate 5 as shown in FIG.
The image pattern changes when the base plate 5 and the object to be fired 4 pushed up into the field of view of the D camera enter. This image change is ITV
It can be accurately detected as a difference image from the basic image on the monitor 10.

In FIG. 4, a slit-shaped monitoring hole 12 is formed in the side wall of the furnace body 2, and a CCD camera 8 is set outside the furnace of the slit-shaped monitoring hole 12 toward the inside of the furnace at a right angle to the furnace axis. It is a schematic sectional drawing which shows an embodiment. Slit-shaped monitoring hole 12
However, when a long tunnel furnace is used, it is formed at a plurality of positions at appropriate intervals, and the CCD camera 8, the image processing device 9, the ITV monitor 10, and the computer 17 corresponding thereto are formed. Is preferably installed.

In this case, the base plate 5 moving in the furnace through the slit-shaped monitoring hole 12 or the side face portion of the base plate 5 and the object to be fired 4 mounted on the top plate 5 is within the visual field, and the normal condition is maintained. When the base plate 5 is conveyed in this state, it is projected on the ITV monitor 10 as a normal image pattern 13 as shown in FIG. 5, and this image pattern does not change. However, when a conveyance abnormal phenomenon occurs due to the push-up of the base plate in the furnace, the normal image pattern 13 changes to the abnormal image pattern 14 as shown in FIG. 6 and is projected on the ITV monitor 10. Therefore, the conveyance abnormality is immediately detected.

When the detection of the abnormal transport phenomenon is captured by the moving base plate or / the change in the speed of the material to be fired, the base plate 5 is used.
It is preferable that a pattern having an emissivity different from that of the base plate material is formed at a constant interval on the side surface monitored by the CCD camera 8. FIG. 7 shows an example of the base plate 5 in which vertical striped patterns 15 having different emissivities are formed at equal intervals, but the form of the pattern is not limited to this. For example, if the base plate 5 is made of an alumina refractory, a powder coating having a different emissivity from alumina, such as silicon carbide or silicon nitride, is applied at regular intervals to form a vertical stripe pattern having a different emissivity. Can be done in any way.

When the furnace is operated using the base plate 5 having such a pattern, the base plate 5 moving in the furnace is captured by the CCD camera 8 as the pattern image pattern 16 of FIG. 7, and the vertical stripe pattern of the base plate 5 is taken. Is projected on the ITV monitor 10 at a constant speed according to the moving speed. Therefore, it is possible to catch the conveyance abnormality by detecting the change in the moving speed. Further, by counting the speed change by the computer 17 and designing the mechanism so that the pusher operation is stopped when the speed change deviates from the normal state, the in-reactor accident can be prevented.

[0020]

As described above, according to the method and apparatus according to the present invention, it is possible to monitor the image pattern or the moving speed of the base plate and / or the object to be fired moving from the outside of the furnace through the CCD camera in the furnace. Thus, it is possible to accurately and promptly detect an abnormal transport phenomenon in the tunnel furnace due to the push-up of the bed plate, etc., and it is possible to prevent a trouble in the furnace in advance by this detection mechanism. Therefore, safe furnace operation is always guaranteed for a long period of time, which is extremely useful especially for the purpose of continuously baking precision members related to semiconductors.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram illustrating a transportation abnormality detection device for a tunnel furnace according to the present invention.

FIG. 2 is a state diagram showing a field of view from the front direction by the CCD camera in the embodiment.

FIG. 3 is an explanatory diagram of an embodiment in which the inside of the furnace is monitored by a CCD camera from the furnace inlet.

FIG. 4 is an explanatory diagram of an embodiment in which the inside of the furnace is monitored by a CCD camera through a slit-shaped monitoring hole.

FIG. 5 is an explanatory diagram showing a normal image pattern according to an embodiment.

FIG. 6 is an explanatory diagram showing an abnormal image pattern according to an example.

FIG. 7 is an explanatory diagram showing a pattern image pattern when a vertical stripe pattern is applied to a base plate.

FIG. 8 is a schematic cross-sectional explanatory view showing the overall configuration of a tunnel furnace having a conventional structure.

FIG. 9 is an explanatory diagram showing a normal transport state.

FIG. 10 is an explanatory diagram showing a state of conveyance abnormality.

[Explanation of symbols]

 1 Heating Element 2 Furnace Body 3 Hearth Track 4 Burned Material 5 Bed Plate 6 Transfer Device 7 Tunnel Furnace 8 CCD Camera 9 Image Processing Device 10 ITV Monitor 11 Exit Space 12 Slit-like Monitoring Hole 13 Normal Image Pattern 14 Abnormal Image Pattern 15 Vertical stripe pattern 16 pattern Image pattern 17 Computer

Claims (5)

[Claims] 1. A bed plate or / and an object to be fired moving in a furnace are monitored by a CCD camera, and a conveyance error of the bed plate in the furnace is detected from a fluctuation or a speed change of an image pattern of the bed plate or / and the object to be fired. A method for detecting abnormal transport in a tunnel furnace, which is characterized by detecting a phenomenon. 2. The method for detecting abnormal transport of a tunnel furnace according to claim 1, wherein the bed plate or / and the object to be fired moving from the entrance or the exit of the tunnel furnace are monitored by a CCD camera. 3. A method for detecting abnormal transport of a tunnel furnace according to claim 1, wherein a bed plate or / and a material to be fired moving in the furnace are monitored from a slit-shaped monitoring hole formed in a side wall portion of the tunnel furnace by a CCD camera. . 4. The method for detecting abnormal transport of a tunnel furnace according to claim 1, wherein a base plate having a pattern showing an emissivity different from that of the base plate at a constant interval is formed on the side surface monitored by the CCD camera. 5. A CCD in which a bed plate or / and a state of carrying an object to be fired in a tunnel furnace are placed within a field of view from outside the furnace.
An apparatus for detecting abnormal transport of a tunnel furnace, which comprises a camera, an image processing apparatus for synthesizing images obtained by the CCD camera, and an ITV monitor for displaying a processed image.