KR102072594B1 - Liquid level detection device, glass manufacturing device, liquid level detection method, and glass manufacturing method - Google Patents

Abstract

This invention is the liquid level detection device 200 which detects the liquid level L of the molten glass 102 accommodated in the melting tank 110, and is formed in the inner wall surface 150 of the glass melting furnace 100 in multiple numbers. A camera 210 photographing at least a portion of each of the reference lines 151a and 152a, the side wall portion 111 of the molten bath 110, and the liquid surface 103 of the molten glass 102, and the camera 210. By image-processing the image 270P, the positional relationship in the some reference line 151a, 152a, the side wall part 111, and the image 270P of the liquid surface 103 is detected, and the detected said positional relationship and The image processing apparatus 220 detects the liquid level L based on the actual positional relationship of the plurality of reference lines 151a and 152a.

Description

Liquid level detection device, glass manufacturing device, liquid level detection method and glass manufacturing method {LIQUID LEVEL DETECTION DEVICE, GLASS MANUFACTURING DEVICE, LIQUID LEVEL DETECTION METHOD, AND GLASS MANUFACTURING METHOD}

The present invention relates to a liquid level level detecting device, a glass manufacturing device, a liquid level level detecting method, and a glass manufacturing method for detecting a liquid level of molten glass contained in a molten bath.

The glass melting furnace is equipped with the melting tank which accommodates a molten glass, and the heating source which heats the inside of a melting tank. The glass raw material thrown in from above from the liquid level of the molten glass in a melting tank is heated by a heating source, and is melt | dissolved in a molten glass gradually.

A detection method for detecting the height of the upper surface of the glass raw material layer floating on the molten glass, wherein the upper surface of the glass raw material layer is irradiated with light from above to image the irradiated portion (bright portion) and the dark portion around the image, and the image is captured. A method of binarizing a processed image has been proposed (see Patent Document 1, for example). In this method, the center of gravity coordinate of the bright part in an image is calculated | required, and the amount of change of the height of the upper surface of a glass raw material layer based on the amount of change of a center of gravity coordinate is detected.

Japanese Patent Laid-Open No. 6-56432

By the way, in a glass melting furnace, it is calculated | required to keep the liquid level of molten glass constant. When the liquid level is fluctuate | varied, the flow volume of the molten glass which flows out from a glass melting furnace to the outside may fluctuate, or the erosion of a melting tank may be promoted.

Conventionally, although the liquid level of the molten glass was measured by the electrode, the naked eye, etc., the measurement precision was not enough.

This invention is made | formed in view of the said subject, and an object of this invention is to provide the liquid level detection apparatus and liquid level detection method which can detect the liquid level of a molten glass with high precision.

In order to solve the above object, the present invention,

It is a liquid level detection device which detects the liquid level of the molten glass accommodated in the melting tank of a glass melting furnace,

A camera for imaging at least a portion of each of a plurality of reference lines formed on an inner wall surface of the glass melting furnace, a side wall portion of the melting tank, and a liquid surface of the molten glass;

By image-processing the image image | photographed with the said camera, the positional relationship in the said several reference line, the side wall part of the said melting tank, and the said liquid surface of the said molten glass is detected, and the detected said positional relationship and the said some A liquid level detection device comprising an image processing device that detects the liquid level based on an actual positional relationship of a reference line.

In addition, the present invention,

It is a liquid level detection method which detects the liquid level of the molten glass accommodated in the melting tank of a glass melting furnace,

Imaging at least a part of each of a plurality of reference lines formed on an inner wall surface of the glass melting furnace, a side wall part of the melting tank, and a liquid surface of the molten glass with a camera,

By image-processing the image image | photographed with the said camera, the positional relationship in the said several reference line, the side wall part of the said molten bath, and the said liquid image of the said molten glass is detected,

A liquid level detection method is provided for detecting the liquid level based on the detected positional relationship and the actual positional relationship of the plurality of reference lines.

According to this invention, the liquid level detection apparatus and liquid level detection method which can detect the liquid level of the molten glass with high precision are provided.

1 is a cross-sectional view showing a glass melting furnace in which a liquid level detection device and a liquid level detection device according to a first embodiment of the present invention are provided.
2 is a cross-sectional view taken along the line II-II of FIG.
3 is an enlarged view of a portion of FIG. 1;
4 is another enlarged view of another portion of FIG. 1.
5 is a cross-sectional view taken along the line VV of FIG. 4.
6 is a schematic diagram illustrating an example of an image captured by a camera.
FIG. 7 is a schematic diagram illustrating a change in luminance in the longitudinal direction of the image of FIG. 6. FIG.
8 is a cross-sectional view showing an example of a melting tank in a state eroded by the molten glass.
9 is a schematic diagram illustrating another example of an image captured by a camera.
FIG. 10 is a schematic diagram showing a change in luminance in the longitudinal direction of the image of FIG. 9. FIG.
It is sectional drawing which shows the structure of the glass manufacturing apparatus by 2nd Embodiment of this invention.

EMBODIMENT OF THE INVENTION Hereinafter, one Embodiment of this invention is described with reference to drawings. In the following drawings, the same or corresponding configuration is given the same or corresponding reference numeral and the description thereof is omitted.

[First Embodiment]

This embodiment relates to the liquid level level detection apparatus and liquid level detection method which detect the liquid level of the molten glass accommodated in the melting tank of a glass melting furnace.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows the glass melting furnace in which the liquid level detection apparatus and liquid level detection apparatus which concern on the 1st Embodiment of this invention are provided. In FIG. 1, the outer edge of the flame (flame) which a burner forms is shown by a 2-dot chain line. FIG. 2 is a cross-sectional view taken along line II-II of FIG. 1. In Fig. 2, in order to make the drawing easier to see, the illustration of the flame and the tuck stone is omitted. 3 is an enlarged view of a portion of FIG. 1. 4 is another enlarged view of another portion of FIG. 1. 5 is a cross-sectional view taken along the line VV of FIG. 4.

(Glass melting furnace)

The glass melting furnace 100 is equipped with the melting tank 110 which accommodates the molten glass 102 as shown in FIG. 1 and FIG. In the melting tank 110, the liquid surface 103 of the molten glass 102 is a horizontal plane.

The melting tank 110 has a box shape opened upward, and is composed of side walls 111, 114, and bottom walls 115 on the front, rear, left, and right sides, as shown in FIGS. 1 and 2. The inner side surface of each side wall part 111-114 is a perpendicular plane, and is a plane perpendicular | vertical with respect to the liquid surface 103. As shown in FIG.

The glass melting furnace 100 includes an upper sidewall portion 121 to 124 disposed above the sidewall portions 111 to 114 and an arched ceiling portion 130 covering the openings of the upper sidewall portions 121 to 124 from above. It is provided integrally.

As shown in FIG. 1, a gap is formed between the left side wall portion 111 and the left upper side wall portion 121, and between the right side wall portion 112 and the right upper side wall portion 122, respectively. In order to prevent this gap, the filling brick (chin stone) 140 is mounted on the upper surface of each side wall part 111 and 112, and is contacting the inner side surface of the corresponding upper side wall part 121 and 122. As shown in FIG.

The inner wall surface 150 of the glass melting furnace 100 has horizontal stepped surfaces 151 and 152 as shown in FIG. 3. One step surface 151 is the upper surface of the jaw stone 140. The other stepped surface 152 is a part of the upper surface of the left side wall portion 111 (the part pushed out from the jaw stone 140 into the furnace). The inner end edges 151a and 152a of the stepped surfaces 151 and 152 are straight lines parallel to the liquid surface 103, and are connected to the intersection 104 of the inner surface 111a of the liquid surface 103 and the left side wall portion 111. It is a parallel straight line.

As shown in FIG. 2, the glass melting furnace 100 includes a burner 160 as a heating source for heating the inside of the melting tank 110. The burner 160 forms a flame (flame) F in an inner space surrounded by the liquid surface 103, the upper sidewall portions 121 to 124, and the ceiling portion 130, and melts by radiant heat from the flame F. The inside of the bath 110 is heated. The burner 160 is provided in plural at intervals in the front-rear direction (X direction in FIG. 2) in each of the left and right upper side wall portions 121 and 122.

The glass melting furnace 100 includes a bubbler 170 that forms bubbles 106 in the molten glass 102. The bubbler 170 has a gas supply pipe 172 penetrating the bottom wall 115 of the melting tank 110, and blows gas (eg, nitrogen gas) from the gas supply pipe 172 to form a bubble 106. To form. As the bubble 106 floats to the liquid surface 103, an upward flow is formed in the molten glass 102, and the molten glass 102 is circulated. The gas supply pipe 172 is provided in the substantially center part of the front-back direction (X direction in FIG. 2) of the melting tank 110. As shown in FIG.

(Level liquid detection device)

The liquid level detection apparatus 200 is an apparatus which detects the liquid level L of the molten glass 102 accommodated in the melting tank 110 as shown in FIG. The liquid level detection device 200 detects the liquid level L by image processing the camera 210 for imaging the interior of the glass melting furnace 100 and the image captured by the camera 210. It is provided.

The liquid level detection device 200 includes a tubular water cooling box 230 disposed outside the glass melting furnace 100. The water cooling box 230 is spaced apart from the glass melting furnace 100 and accommodates the camera 210 therein. The camera 210 captures an image of the interior of the glass melting furnace 100 through the monitoring window 180 formed through the furnace wall (eg, the upper right side wall portion 122) of the glass melting furnace 100.

The liquid level detection apparatus 200 is a cylindrical housing 240 that is installed to surround the monitoring window 180 on the outer surface of the glass melting furnace 100 and a transparent blocking portion of the opening of the camera 210 side of the housing 240. A plate (eg, quartz glass plate) 250 is provided. The camera 210 captures the inside of the glass melting furnace 100 through the transparent plate 250, the inner space of the housing 240, and the monitoring window 180.

The housing 240 is formed of, for example, a heat resistant alloy. An annular seal member 260 is provided between the housing 240 and the outer surface of the glass melting furnace 100. The seal member 260 closes a slight annular gap formed between the housing 240 and the glass melting furnace 100.

As shown in FIGS. 4 and 5, the housing 240 is provided with gas supply ports 241 to 244 for supplying a gas (for example, compressed air) into the housing 240. Each of the gas supply ports 241 to 244 is connected to a gas supply source such as a compressor via a pipe P on which an on-off valve and a flowmeter are provided. When the gas supply source is operated to open and close the valve, gas is supplied into the housing 240. Gas supplied into the housing 240 is introduced into the glass melting furnace 100 through the monitoring window 180. At this time, the flow of gas in the monitoring window 180 is regulated in one direction as shown in FIG. 5. This is because the opening on the camera 210 side of the monitoring window 180 is surrounded by the housing 240, and the opening on the camera 210 side of the housing 240 is blocked by the transparent plate 250. In this way, since the flow of gas in the monitoring window 180 is regulated in one direction, it is possible to prevent the vapor of the volatile component (for example, boric acid) of the molten glass 102 from flowing into the housing 240. Therefore, the transparent plate 250 can be prevented from blurring. Moreover, the influence of the heat of flame F can be suppressed.

Each gas supply port 241 to 244 is a long slit in the circumferential direction of the housing 240 as shown in FIG. 4, and the gas curtain perpendicular to the direction of the central axis of the housing 240 as shown in FIG. 5. To form. A set of gas supply ports 241 and 242 are disposed opposite to the quadrangular housing 240 so that the gas curtains collide with each other. Similarly, another set of gas supply ports 243 and 244 are arranged opposite to the quadrangular housing 240. One set of gas supply ports 241 and 242 is disposed closer to the camera 210 than the other set of gas supply ports 243 and 244.

(camera)

The camera 210 is, for example, a CCD camera, a CMOS camera, or the like. The camera 210 is connected to the other sidewall portion (eg, the left sidewall) through the monitoring window 180 formed in one upper sidewall portion (eg, the upper right sidewall portion 122) as shown in FIG. 1. A part of the part 111 is imaged. The optical axis A of the camera 210 is disposed substantially perpendicular to the inner side surface 111a of the left sidewall portion 111 when viewed from the top. The angle θ formed between the optical axis A and the horizontal plane B of the camera 210 is, for example, 0 to 7 °. The distance H in the horizontal direction between the camera 210 (center of the camera front face) and the left side wall portion 111 is, for example, 5 m or more. In this way, by setting the angle θ to be 0 to 7 ° and the distance H to 5 m or more, it is possible to use an approximation equation in the image processing described later. The distance V in the up-down direction between the camera 210 (center of the camera front surface) and the left side wall portion 111, the focal length, resolution, and the like of the camera 210 are appropriately selected.

The camera 210 includes at least a portion of each of the plurality of reference lines formed on the inner wall surface 150 of the glass melting furnace 100, the left sidewall portion 111 of the melting tank 110, and the liquid surface 103 of the molten glass 102. Image. As the reference line, for example, the inner end edges 151a and 152a of the horizontal step surfaces 151 and 152 are used. Hereinafter, the inner end edges 151a and 152a are also called reference lines 151a and 152a. These reference lines 151a and 152a are straight lines parallel to the liquid surface 103, and are straight lines parallel to the intersection 104 of the liquid surface 103 and the inner side surface 111a of the left side wall portion 111.

In addition, although the reference lines 151a and 152a of this embodiment are the edges of the step surfaces 151 and 152, the bricks which comprise the furnace wall (for example, left upper side wall part 121) of the glass melting furnace 100 are comrades The line in between may be sufficient, and is not specifically limited.

In addition, although the reference lines 151a and 152a of this embodiment are straight lines parallel to the intersection 104, they may be a straight line which is oblique with respect to the intersection 104, and a straight line perpendicular to the intersection 104.

In addition, as said reference line, any two points may be taken and the line connecting the two points may be used as the reference line.

6 is a schematic diagram illustrating an example of an image captured by a camera. FIG. 7 is a schematic diagram illustrating a change in luminance in the longitudinal direction of the image of FIG. 6. In FIG. 7, the horizontal axis represents the distance from the upper edge of the image of FIG. 6, and the vertical axis represents the luminance.

As illustrated in FIG. 6, the image 270P (hereinafter also referred to as the "photographed image 270P") captured by the camera 210 includes the image 121P of the upper left side wall portion 121 and the jaw stone ( The image 140P of 140, the image 111P of the left side wall part 111, and the image 103P of the liquid surface 103 are included. The picked-up image also includes images 151aP and 152aP of the plurality of reference lines 151a and 152a and images 104P of the intersection 104. In the picked-up image 270P, the baseline images 151aP and 152aP and the intersection image 104P are straight lines parallel to each other.

As shown in FIG. 7, the luminance (brightness) of the pixel in the picked-up image 270P changes abruptly at the position x1, x2 of the reference line image 151aP, 152aP, and the position x3 of the cross-section image 104P. As shown in FIG. 3, the shape of the light reflection surface changes rapidly in the actual reference lines 151a and 152a and the intersection 104. The light reflection surface is a surface which reflects light from a flame as a light source toward the camera.

In addition, the change of the brightness | luminance in the position x1 in the picked-up image 270P includes the influence of the shape change of the light reflection surface in the outer edge 151b of the step surface 151. As shown in FIG. This is because the outer edge 151b and the inner edge 151a are located at substantially the same position in the captured image 270P. Similarly, the change in the luminance at the position x2 in the captured image 270P includes the influence of the shape change of the light reflection surface on the outer edge 152b of the step surface 152.

By the way, since the molten glass 102 accommodated in the melting tank 110 is obtained by melting the glass raw material of a powder state or a particle state, it contains the bubble inside.

It is preferable that the imaging area | region of the liquid surface 103 by the camera 210 exists in the peripheral areas 108 and 109 (refer FIG. 2) of the area | region where the bubble 106 floats. Here, a "peripheral area" means an area (C1 = D1 = 10 mm, C2 = D2 = 1500) in which the distance in the front-rear direction (X direction in FIG. 2) between the gas supply pipe 170 is 10 to 1500 mm. Mm). Since these peripheral areas 108 and 109 are substantially bubble free mirror surfaces, there is little scattering of light. Therefore, it is suitable for the image process mentioned later which detects the change of the brightness | luminance of the pixel in the picked-up image 270P. In addition, the imaging area | region of the liquid surface 103 by the camera 210 should just be an area where there is no bubble substantially, and is not limited to the said peripheral area | regions 108 and 109.

The captured image 270P is transmitted to the image processing apparatus 220 via the signal line.

(Image processing device)

The image processing apparatus 220 is an apparatus which image-processes the picked-up image 270P, and detects the liquid level L. FIG. The image processing apparatus 220 is configured as a computer including a CPU, a recording medium, and the like. The image processing apparatus 220 executes various processes described later by executing various programs stored in the recording medium on the CPU.

First, the image processing apparatus 220 specifies the position x1, x2 of the reference line images 151aP and 152aP, and the position x3 of the intersection image 104P based on the change of the brightness | luminance of the pixel in the picked-up image 270P.

For example, the image processing apparatus 220 detects a change in luminance with respect to a pixel column including a plurality of pixels arranged in a predetermined direction (for example, a direction orthogonal to the intersection image 104P). This process is performed using a differential filter, for example. Differential is either primary or secondary (laplacian). The pixel string used for this processing is previously selected by a test or the like.

Detection of the change in luminance is preferably performed using a plurality of pixel columns in one picked-up image 270P in order to improve the accuracy. In addition, the number of sheets of the captured image 270P used for the detection of the change in luminance is preferably two or more sheets for error suppression, and the imaging is preferably performed within 60 seconds for suppression of time variation.

The image processing apparatus 220 specifies the place where the luminance of the pixel in the picked-up image 270P changes abruptly as the position x1, x2 of the reference line images 151aP and 152aP, and the position x3 of the cross-section image 104P. The position is specified in sub-pixels (for example, about 0.1 pixel).

Next, the image processing apparatus 220 calculates the space | interval J1 (refer FIG. 6) of reference line image 151aP, 152aP, and the space | interval J2 (refer FIG. 6) of one reference line image 152aP and cross-section image 104P. .

In addition, the image processing apparatus 220 reads out the actual space | interval K1 (refer FIG. 1) of the reference lines 151a and 152a from a recording medium. The interval K1 is a distance in the vertical direction. The interval K1 does not vary in time, so it is measured in advance and recorded in the recording medium.

Next, the image processing apparatus 220 calculates the actual space K2 (see FIG. 1) between one reference line 152a and the intersection 104 based on the spaces J1, J2, and K1. Calculation of the interval K2 is performed using an approximation formula (K2 = K1 × J2 / J1). You may use arrangement information (for example, angle | corner (theta), distance H, and distance V which are shown in FIG. 1) of camera 210 in calculation of space | interval K2. The interval K2 is a distance in the vertical direction.

Next, the image processing apparatus 220 reads from the recording medium the actual distance K0 (see FIG. 1) between one reference line 152a and the inner bottom surface of the melting tank 110. The distance K0 is a distance in the vertical direction. Since the distance K0 does not fluctuate in time, it is measured in advance and recorded in the recording medium.

Finally, the image processing apparatus 220 calculates the liquid level L based on the distance K0 and the distance K2 (L = K0-K2). In addition, although the reference surface of the liquid level L of this embodiment is an inner bottom face of the melting tank 110, the upper surface of the melting tank 110 may be sufficient. In this case, since L = K2, the data of K0 is unnecessary.

In this way, the image processing apparatus 220 performs image processing on the picked-up image 270P, so that the image processing apparatus 220 applies the picked-up images 270P of the plurality of reference lines 151a and 152a, the left side wall portion 111, and the liquid surface 103. The positional relationship (intervals J1, J2) is detected. In addition, the image processing apparatus 220 detects the liquid level L of the molten glass 102 based on the detected positional relationship and the actual positional relationship (distance K1) of the plurality of reference lines 151a and 152a.

In the present embodiment, since the liquid level L is detected using a plurality of reference lines 151a and 152a formed on the inner wall surface 150 of the glass melting furnace 100, the actual reference lines of the plurality of reference lines 151a and 152a are used. With reference to the positional relationship, the liquid level L can be detected with high accuracy.

In addition, in this embodiment, since one reference line 152a is a straight line parallel to the liquid surface 103, one reference line image 152aP and the intersection image 104P become parallel in the picked-up image 270P. Therefore, since the positional relationship between one reference line 152a and the intersection 104 is determined by one parameter (interval J2), the positional relationship can be easily specified.

[Modification of First Embodiment]

This modification is related with the image processing when the side wall part 111 of the molten bath 110 was eroded by the molten glass 102. FIG.

It is sectional drawing which shows an example of the melting tank in the state eroded by the molten glass. 9 is a schematic diagram illustrating another example of an image captured by a camera. FIG. 10 is a schematic diagram showing a change in luminance in the longitudinal direction of the image of FIG. 9. In FIG. 10, the horizontal axis represents the distance from the upper edge of the image of FIG. 9, and the vertical axis represents the luminance.

As shown in FIG. 8, the recessed part 116 is formed in the inner side surface 111a of the left side wall part 111 by the influence of the erosion by the molten glass 102. As shown in FIG. There is a liquid surface 103 to the inside of the concave portion 116, and the inner wall surface of the concave portion 116 has a negative portion 117 to which light from the flame F, which is a light source, does not reach above the liquid surface 103. Have The dark part 118 is formed in the liquid level 103 by the negative part 117 shining on the liquid level 103.

As shown in FIG. 9, the picked-up image 270AP includes the image 121P of the upper left side wall portion 121, the image 140P of the tuck stone 140, and the image 111P of the left side wall portion 111. ) And the image 103P of the liquid surface 103. The captured image includes images 151aP and 152aP of the plurality of reference lines 151a and 152a, an image 117P of the sound portion 117, and an image 118P of the dark portion 118. The negative image 117P and the dark image 118P are continuously connected to constitute a strip-shaped image 262P having low luminance.

Between the both edges of the strip | belt-shaped image 262P, the extended surface of the planar part of the inner side surface 111a of the left side wall part 111, and the image 104AP of the intersection 104A of the liquid surface 103 are hidden. In addition, the actual intersection 104A is an imaginary line.

One side edge of the strip | belt-shaped image 262P is the image 117aP of the rim | tip 117 upper end edge 117a. The other side edge of the strip | belt-shaped image 262P is the image 118aP of the front-end | tip edge 118a of the arm part 118. As shown in FIG.

The base line images 151aP and 152aP, the both edges of the strip-shaped image 262P, and the intersection image 104AP are straight lines parallel to each other.

As shown in Fig. 10, the luminance (brightness) of the pixels in the picked-up image 270AP is different from the positions x1 and x2 of the baseline images 151aP and 152aP, and at positions x5 and x6 of both edges of the strip-shaped image 262P. Change suddenly.

First, the image processing apparatus 220 detects a change in luminance with respect to a pixel string including a plurality of pixels arranged in a predetermined direction (for example, a direction orthogonal to the band-shaped image 262P), and the luminance suddenly changes. The place to be specified is identified as positions x1 and x2 of the reference line images 151aP and 152aP and positions x5 and x6 of both edges of the band-shaped image 262P.

Subsequently, the image processing apparatus 220 approximately specifies the center positions of the positions x5 and x6 of both edges of the specified band-shaped image 262P as the positions of the cross-sectional images 104AP. You may use arrangement information (for example, angle | corner (theta), distance H, and distance V which are shown in FIG. 1) of the camera 210 in specification of the position of the intersection image 104P.

Thereafter, the image processing apparatus 220 detects the liquid level L in the same manner as in the first embodiment. Therefore, similarly to the first embodiment, the liquid level L can be detected with high accuracy.

Second Embodiment

This embodiment relates to the glass manufacturing method provided with the glass manufacturing apparatus provided with the liquid level detection apparatus, and the liquid level detection method.

It is sectional drawing which shows the structure of the glass manufacturing apparatus by 2nd Embodiment of this invention.

In addition to the glass melting furnace 100 and the liquid level detection device 200, the glass manufacturing apparatus 1000 supplies from the input apparatus 300 which injects the glass raw material G into the glass melting furnace 100, and the glass melting furnace 100 from it. The shaping | molding apparatus 400 which shape | molds the molten glass 102 to become a predetermined shape is provided.

The feeding device 300 is, for example, a driving source such as a blanket feeder 320 for feeding the glass raw material G dropped from the hopper 310 into the glass melting furnace 100, and a motor for driving the blanket feeder 320. 330.

In addition, the input device 300 may be provided with a screw feeder, for example, and the system of a feeder is not specifically limited. In addition, a batch system may be sufficient as a batch type | mold or a continuous type | mold may be sufficient as it.

The liquid level detection device 200 controls the input amount of the glass raw material G by the injecting device 300 based on the detected liquid level L. FIG. As illustrated in FIG. 11, the image processing apparatus 220 may be performed or a dedicated computer may be used to control the input amount of the glass raw material G. The control of the input amount of the glass raw material G is performed by controlling the drive source 330.

According to this embodiment, since the detection precision of the liquid level L is high, the fluctuation | variation of the liquid level L is suppressed by controlling the injection amount of the glass raw material G based on the detected liquid level L. FIG. Therefore, the erosion of the melting tank 110 can be slowed down.

The molding apparatus 400 is, for example, a float molding apparatus and includes a float bath 410 for receiving molten metal (eg, molten tin) 402. The shaping | molding apparatus 400 shape | molds to the large plate shape by flowing the molten glass 102 supplied from the glass melting furnace 100 on a molten metal 402 in a predetermined direction, and manufactures a glass ribbon.

By the way, the flow volume of the molten glass 102 supplied from the glass melting furnace 100 to the shaping | molding apparatus 400 is the liquid surface 103 of the molten glass 102 in the glass melting furnace 100, and the float bath 410. It is mainly determined by the height difference of the liquid level of the molten metal 402 in the process.

According to this embodiment, since the fluctuation | variation of the liquid level L in the glass melting furnace 100 is reduced, the fluctuation | variation of the flow volume of the molten glass 102 which flows into the shaping | molding apparatus 400 is suppressed. Therefore, since the thickness of a glass ribbon is stabilized, the product with a uniform thickness is obtained.

In addition, the shaping | molding apparatus 400 may be a fusion shaping | molding apparatus, for example, and is not specifically limited.

Moreover, the defoaming apparatus (not shown) which defoases the bubble in the molten glass 102 produced by the glass melting furnace 100 may be provided between the shaping | molding apparatus 400 and the glass melting furnace 100. As a defoaming apparatus, there exists a vacuum degassing apparatus etc., for example.

The glass ribbon molded in the shape of a large plate in the molding apparatus 400 is cooled while flowing in the float bath 410 in a predetermined direction. By the lift out roll 500 provided near the exit of the float bath 410, a glass ribbon is lifted from the molten metal 402, and is conveyed to the slow cooling apparatus 600. As shown in FIG.

The slow cooling apparatus 600 slow-cools the glass shape | molded by the shaping | molding apparatus 400. FIG. The slow cooling apparatus 600 is equipped with the tunnel path 610 of a heat insulation structure, and the conveyance roller 620 which conveys glass in the tunnel path 610, for example. The conveying rollers 620 are arranged in plural at intervals in the conveying direction. When the conveyance roller 620 is rotationally driven by a motor etc., glass is conveyed horizontally on the conveyance roller 620. The glass carried out from the slow cooling apparatus 600 is cut | disconnected to predetermined dimension shape with a cutter, and it turns into a product.

Although the glass manufactured by the glass manufacturing apparatus 1000 is not specifically limited, Glass substrates for flat panel displays (FPD), such as a liquid crystal display (LCD), a plasma display (PDP), an organic electroluminescent display, and cover glass may be sufficient.

In recent years, thinning of FPD is progressing, thinning of plate glass for FPD is progressing, thickness of 3 mm or less is requested | required as thickness of the plate glass for FPD, and thickness of 2 mm or less may be required. The thickness of the plate glass for LCD or organic EL is 1.3 mm or less, preferably 1.0 mm or less, more preferably 0.7 mm or less, still more preferably 0.5 mm or less, particularly preferably 0.3 mm or less, even more particularly preferably 0.1 mm or less.

According to this embodiment, since the thickness of a glass ribbon is stabilized, the plate glass for FPD of the thickness of the said range can be manufactured with high precision.

Although the kind of glass manufactured by the glass manufacturing apparatus 100 is not specifically limited, For example, alkali free glass may be sufficient. The alkali-free glass is an alkali metal oxide (Na ₂ O, K ₂ O, Li ₂ O) that is substantially free of (that is, with the exception of inevitable impurities, which do not contain an alkali metal oxide) glass. The alkali-free total amount of the content of alkali metal oxides _{(Na 2 O + K 2 O} + Li 2 O) in the glass, for example, may be 0.1% or less. The chemical composition of the glass is measured by a fluorescence X-ray analyzer.

The alkali free glass is, for example, in terms of mass percentage on an oxide basis, SiO ₂ : 50 to 73%, preferably 50 to 66%, Al ₂ O ₃ : 10.5 to 24%, B ₂ O ₃ : 0 to 12 %, MgO: 0 to 8%, CaO: 0 to 14.5%, SrO: 0 to 24%, BaO: 0 to 13.5%, ZrO ₂ : 0 to 5%, MgO + CaO + SrO + BaO: 8 To 29.5%, preferably 9 to 29.5%.

The alkali free glass has a high distortion point and, in consideration of solubility, is preferably expressed in terms of mass percentage based on oxide, and has SiO ₂ : 58 to 66%, Al ₂ O ₃ : 15 to 22%, and B ₂ O ₃ : 5 to 12%, MgO: 0 to 8%, CaO: 0 to 9%, SrO: 3 to 12.5%, BaO: 0 to 2%, and MgO + CaO + SrO + BaO: 9 to 18%.

Alkali-free glass, in particular, in consideration of solubility, is preferably expressed in terms of mass percentage based on oxide, and SiO ₂ : 50 to 61.5%, Al ₂ O ₃ : 10.5 to 18%, B ₂ O ₃ : 7 to 10% , MgO: 2 to 5%, CaO: 0 to 14.5%, SrO: 0 to 24%, BaO: 0 to 13.5%, MgO + CaO + SrO + BaO: 16 to 29.5%.

Alkali-free glass, especially when considering the high strain point, preferably in terms of mass percentage display on the basis of oxide, SiO ₂ : 56 to 70%, Al ₂ O ₃ : 14.5 to 22.5%, B ₂ O ₃ : 0 to 2%, MgO: 0 to 6.5%, CaO: 0 to 9%, SrO: 0 to 15.5%, BaO: 0 to 2.5%, MgO + CaO + SrO + BaO: 10 to 26%.

The alkali-free glass, especially if high distortion point and solubility to consider include, as preferably the mass percentage display of the oxide basis, SiO _2: 54 to _{73%, Al 2 O 3:} 10.5 to 22.5%, B ₂ O _3: 1.5 to 5.5%, MgO: 0 to 6.5%, CaO: 0 to 9%, SrO: 0 to 16%, BaO: 0 to 2.5%, MgO + CaO + SrO + BaO: 8 to 25%.

As mentioned above, although the liquid level detection apparatus and the liquid level detection method were demonstrated in embodiment etc., this invention is not limited to the said embodiment etc., Various deformation | transformation and improvement are possible in the range of the summary of this invention described in the claim. Do.

This application claims the priority based on Japanese Patent Application No. 2011-174210 for which it applied to Japan Patent Office on August 9, 2011, and uses the whole content of Japanese Patent Application No. 2011-174210 for this international application. .

100: glass melting furnace
102: molten glass
103: face value
104: intersection
106: bubble
110: melting tank
111: left side wall portion
122: right upper sidewall portion
150: inner wall surface of the glass melting furnace
151: step surface
151a: medial end border (baseline)
152: step surface
152a: inner edge (baseline)
170: bubbler
180: watch window
200: liquid level detection device
210: camera
220: image processing device
240: housing
241 to 244: gas supply port
250: transparent plate
260: seal member
270P: Burn
300: input device
400: forming apparatus
1000: glass manufacturing apparatus

Claims (17)

It is a liquid level detection device which detects the liquid level of the molten glass accommodated in the melting tank of a glass melting furnace,
A camera for imaging at least a portion of each of a plurality of reference lines formed on an inner wall surface of the glass melting furnace, a side wall portion of the melting tank, and a liquid surface of the molten glass;
By image-processing the image image | photographed with the said camera, the positional relationship in the said several reference line, the side wall part of the said melting tank, and the said liquid surface of the said molten glass is detected, and the detected said positional relationship and the said some An image processing apparatus for detecting the liquid level based on an actual positional relationship of a reference line;
The camera captures the inside of the glass melting furnace through a spyhole installed outside the glass melting furnace and penetrating through the furnace wall of the glass melting furnace,
The liquid level detection device,
A cylindrical housing installed to surround the monitoring window on an outer surface of the glass melting furnace;
A transparent plate for blocking an opening at the camera side of the housing;
And a gas supply port for supplying gas into the housing is formed in the housing. The liquid level detection device according to claim 1, wherein one reference line is a straight line parallel to the liquid level. The liquid level detection device according to claim 2, wherein the one reference line is an edge between the end edge of the step surface parallel to the liquid surface or a joint line between the bricks forming the furnace wall of the glass melting furnace. delete The optical axis of the camera according to any one of claims 1 to 3, wherein the optical axis of the camera is disposed perpendicularly to an inner side surface of the side wall portion picked up by the camera, as viewed from an upper surface,
The angle formed by the optical axis of the camera and the horizontal plane is 0 to 7 °,
A liquid level detection device having a distance in the horizontal direction between the inner side surface of the side wall portion picked up by the camera and the camera is 5 m or more. The liquid level detection device according to any one of claims 1 to 3, wherein the imaging area of the liquid level by the camera is an area substantially free of bubbles. The said glass melting furnace is provided with the bubbler which forms a bubble in the said molten glass,
And an imaging area of the liquid level by the camera is in a peripheral area of an area where the bubble floats. The liquid level detection device according to any one of claims 1 to 3, the glass melting furnace, an input device for introducing a glass raw material into the glass melting furnace, and a molten glass supplied from the glass melting furnace in a predetermined shape. In the glass manufacturing apparatus provided with the shaping | molding apparatus to shape | mold,
The liquid level detection device is a glass manufacturing apparatus for controlling the input amount by the input device based on the detected liquid level. It is a liquid level detection method which detects the liquid level of the molten glass accommodated in the melting tank of a glass melting furnace,
Imaging at least a part of each of a plurality of reference lines formed on an inner wall surface of the glass melting furnace, a side wall part of the melting tank, and a liquid surface of the molten glass with a camera,
By image-processing the image image | photographed with the said camera, the positional relationship in the said several reference line, the side wall part of the said molten bath, and the said liquid image of the said molten glass is detected,
Detect the liquid level based on the detected positional relationship and the actual positional relationship of the plurality of reference lines,
The camera captures the inside of the glass melting furnace through a monitoring window provided outside the glass melting furnace and penetrated through the furnace wall of the glass melting furnace,
A cylindrical housing is installed on the outer surface of the glass melting furnace to surround the monitoring window, and the opening at the camera side of the housing is blocked by a transparent plate.
And a liquid level detection method in which gas is supplied into the housing. 10. The liquid level detection method according to claim 9, wherein one reference line is a straight line parallel to the liquid level. The liquid level detection method according to claim 10, wherein one of the reference lines is an edge between the edges of the step surface parallel to the liquid surface or a joint line between the bricks forming the furnace wall of the glass melting furnace. delete The optical axis of the camera according to any one of claims 9 to 11, wherein the optical axis of the camera is disposed perpendicularly to an inner side surface of the side wall portion picked up by the camera, as viewed from an upper surface,
The angle formed by the optical axis of the camera and the horizontal plane is 0 to 7 °,
And a distance in the horizontal direction between the inner side surface of the side wall portion picked up by the camera and the camera is 5 m or more. The liquid level detection method according to any one of claims 9 to 11, wherein the imaging area of the liquid level by the camera is an area substantially free of bubbles. The said glass melting furnace is provided with the bubbler which forms a bubble in the said molten glass,
And an imaging area of the liquid level by the camera is in a peripheral area of an area where the bubble floats. A process of controlling the input amount of the glass raw material into the glass melting furnace based on the liquid level of the molten glass detected by the liquid level detection method according to any one of claims 9 to 11;
The glass manufacturing method which has the process of shape | molding the molten glass supplied from the said glass melting furnace to a predetermined shape. The glass to be produced is an alkali free glass, wherein the alkali free glass is expressed in terms of mass percentage based on oxide, and SiO ₂ : 50 to 73%, Al ₂ O ₃ : 10.5 to 24%, B ₂ O ₃ : 0 to 12%, MgO: 0 to 8%, CaO: 0 to 14.5%, SrO: 0 to 24%, BaO: 0 to 13.5%, ZrO ₂ : 0 to 5%, containing MgO + CaO + SrO + BaO: The glass manufacturing method is 8 to 29.5%.

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