JP2022050001A - Glass plate production method and production device - Google Patents

Abstract

To make a clarification pipe properly inclined to prevent an increase in the inner pressure of the clarification pipe and also prevent the retention of bubbles in melted glass inside the clarification pipe.SOLUTION: A glass plate production device 1 comprises: a melting furnace 2 for producing melted glass Gm by heating glass raw material; a clarification pipe 5 made of a noble metal for performing a clarification process on the melted glass Gm produced by the melting furnace 2; and formation means 4 for using the melted glass Gm, which has been subjected to the clarification process, to form a glass ribbon Gr, wherein the clarification pipe 5 is inclined to be higher in a downstream direction, and the clarification pipe 5 has an inclination angle α of 0.25° to 5° with respect to the horizontal axis.SELECTED DRAWING: Figure 1

Description

The present invention relates to a glass plate manufacturing method and a manufacturing apparatus thereof, and more particularly to a glass plate manufacturing method and a manufacturing apparatus thereof including a step of performing a clarification treatment on molten glass with a clarification tube.

As is well known, a glass plate is used as a glass substrate or a cover glass in, for example, a display (liquid crystal display, plasma display, organic EL display, etc.) and organic EL lighting.

This type of glass plate is generally used in a melting step of producing molten glass, a clarification step of applying a clarification treatment to the formed molten glass, a homogenization step of stirring the molten glass after the clarification treatment, and a homogenization step. It is manufactured through a molding process of molding a glass ribbon using the molten glass of.

A specific configuration of an apparatus used for manufacturing this glass plate is disclosed in, for example, Patent Document 1. This device consists of a melting furnace that performs a melting process, a clarification tube (clarification tank) made of a precious metal such as platinum or a platinum alloy that performs a clarification process, and a plurality of homogenization processes (two in the same document) in order from the upstream side. It is equipped with a stirring pot, a molding means for performing a molding process, and the like.

Japanese Unexamined Patent Publication No. 2014-19629

By the way, the clarification pipe disclosed in Patent Document 1 is inclined so as to be in a higher position as it moves to the downstream side (see FIG. 1 of the same document). As a result of diligent research, the present inventors have found that even if the clarified pipe is tilted in this way, the following problems occur if the mode of tilting is not appropriate.

It has been found that when the inclination angle of the clarified pipe with respect to the horizontal axis is large as in Patent Document 1, the internal pressure of the clarified pipe particularly near the inflow port becomes large, and the clarified pipe may be damaged or damaged. On the other hand, when the clarification tube is made horizontal with respect to the horizontal axis, that is, when the clarification tube is made horizontal, the bubbles generated in the molten glass in the clarification tube are stagnant, and the stagnant bubbles oxidize the inner surface of the clarification tube. It was found that a large amount of precious metal foreign matter (platinum bubbles, etc.) can be generated.

From the above viewpoint, the present invention aims to achieve both the prevention of foam stagnation in the clarification pipe and the prevention of the increase in the internal pressure of the clarification pipe by appropriately adjusting the inclination of the clarification pipe. Make it an issue.

The first aspect of the present invention, which was devised based on the above findings by the present inventors, is a melting step of heating a glass raw material to produce molten glass and a molten glass produced in the melting step made of noble metal. It is a method for manufacturing a glass plate including a clarification step of supplying a clarification tube to perform a clarification treatment and a molding step of forming a glass ribbon using the molten glass that has undergone the clarification step, wherein the clarification tube is downstream. It is characterized in that the tilt angle of the clarification tube with respect to the horizontal axis is 0.25 to 5 ° as well as tilting to a higher position as it shifts to the side.

According to such a configuration, not only the clear pipe is tilted to a higher position as it moves to the downstream side, but also the tilt angle of the clear pipe with respect to the horizontal axis is 0.25 to 5 °. By doing so, the following advantages can be obtained. That is, when the inclination angle of the clarification tube is 0.25 ° or more, the bubbles generated in the molten glass in the clarification tube move smoothly toward the downstream side. Therefore, it is possible to avoid a situation in which an unacceptable amount of bubbles remains in the clear pipe. On the other hand, when the inclination angle of the clarification tube is less than 0.25 °, bubbles are stagnant in the clarification tube, and the inner surface of the clarification tube is oxidized by the stagnant bubbles, and a large amount of precious metal foreign matter (platinum lumps, etc.) ) Will occur. Therefore, the quality of the manufactured glass plate is deteriorated and the product yield is also deteriorated. In the present invention, it is possible to avoid a situation in which bubbles are stagnant in the clear pipe, so that such a problem is unlikely to occur. Moreover, in the present invention, since the inclination angle of the clarified pipe is 5 ° or less, the internal pressure of the clarified pipe, particularly near the inflow port, does not increase, and the clarified pipe is less likely to be damaged or damaged. This improves the durability of the clarified pipe. On the other hand, when the inclination angle of the clarified pipe exceeds 5 °, the internal pressure of the clarified pipe, particularly near the inflow port, increases, and the clarified pipe is liable to be damaged or damaged. From the above circumstances, according to the present invention, it is possible to achieve both prevention of stagnation of bubbles in the clarification pipe and prevention of increase in the internal pressure of the clarification pipe. In consideration of such circumstances, it is more preferable that the lower limit of the inclination angle of the clarification pipe is 0.5 °. Further, the upper limit value is more preferably 2 °.

In this configuration, vent portions for discharging bubbles generated in the molten glass may be provided at a plurality of locations in the clear pipe in the direction from the upstream side to the downstream side.

By doing so, it is possible to surely discharge the bubbles from the inside of the clarification tube. That is, when the amount of bubbles in the clear pipe is excessive and an attempt is made to discharge the bubbles from one vent portion, the bubbles reach the vent portion continuously or intermittently, so that the inner surface of the clear pipe around the vent portion is reached. May be continuously or intermittently exposed to gas and oxidized. If a plurality of vent portions are provided, the amount of bubbles discharged from one vent portion is reduced, so that the bubbles reach the vent portions intermittently. Therefore, the time that the inner surface of the clarification tube around the vent portion is exposed to the gas can be reduced, and the concern about oxidation can be eliminated.

Instead of this configuration, the clarification pipe is divided into a plurality of compartments in the direction from the upstream side to the downstream side, and each compartment is provided with a vent portion for discharging bubbles generated in the molten glass. May be good. Here, the sectioned area means a sectioned area for individually adjusting the temperature (by energization heating or the like).

By doing so, the bubbles generated in each section region can be discharged, so that the amount of bubbles discharged from one vent portion becomes appropriate. Therefore, the time that the inner surface of the clear pipe around the vent portion is exposed to the gas can be reduced more reliably, and the concern about oxidation can be more reliably eliminated.

The second aspect of the present invention, which was devised based on the above findings by the present inventors, is a melting furnace that heats a glass raw material to produce molten glass and a clarification treatment for the molten glass produced by the melting furnace. It is a glass plate manufacturing apparatus provided with a clarification tube made of precious metal to be applied and a molding means for forming a glass ribbon using the molten glass subjected to the clarification treatment, and the clarification tube is moved to the downstream side. It is characterized in that the tilting angle of the clearing tube with respect to the horizontal axis is 0.25 to 5 ° as well as tilting to a higher position.

According to this manufacturing apparatus, it is possible to obtain the same operation and effect as the above-mentioned manufacturing method having substantially the same configuration as the manufacturing apparatus.

According to the present invention, the mode of inclination of the clarification tube is optimized, and it is possible to achieve both prevention of stagnation of bubbles generated in the molten glass in the clarification tube and prevention of an increase in the internal pressure of the clarification tube. Be done.

It is a schematic front view which shows the whole structure of the glass plate manufacturing apparatus which concerns on embodiment of this invention. It is a flowchart for demonstrating the manufacturing method of the glass plate which concerns on embodiment of this invention. It is a vertical sectional front view which shows the manufacturing method of the glass plate which concerns on 1st Embodiment of this invention, and the clarification tube which is a main component of the manufacturing apparatus. It is a vertical sectional side view cut according to the line AA of FIG. It is a vertical sectional front view which shows the manufacturing method of the glass plate which concerns on 2nd Embodiment of this invention, and the clarification tube which is a main component of the manufacturing apparatus. It is a vertical sectional front view which shows the clarification tube which is a main component of the manufacturing method of the glass plate which concerns on the 3rd Embodiment of this invention, and the manufacturing apparatus thereof.

Hereinafter, the method for manufacturing a glass plate and the manufacturing apparatus thereof according to the embodiment of the present invention will be described with reference to the accompanying drawings.

FIG. 1 illustrates a manufacturing apparatus for carrying out the method for manufacturing a glass plate according to the present invention. As shown in the figure, the manufacturing apparatus 1 is roughly divided into a melting furnace 2 which is deployed at the upstream end and heats a glass raw material to generate molten glass Gm, and a melting glass Gm flowing out from the melting furnace 2. A transfer device 3 for transferring toward the downstream side and a molding means 4 for forming a glass ribbon Gr using the molten glass Gm supplied from the transfer device 3 are provided.

The transfer device 3 has a clarification pipe (clarification tank) 5, a stirring pot (stirring tank) 6, and a state adjusting pot (state adjusting tank) 7 in order from the upstream side. The inflow port 5a of the clarification pipe 5 leads to the outflow port 2b of the melting furnace 2 via the first connecting pipe 8. The outlet 5b of the clarification pipe 5 leads to the inlet 6a of the stirring pot 6 via the second connecting pipe 9. The outlet 6b of the stirring pot 6 leads to the inlet 7a of the state adjusting pot 7 via the cooling pipe 10.

The clarification pipe 5 is for clarifying the molten glass Gm produced in the melting furnace 2. The stirring pot 6 stirs the clarified molten glass Gm to perform a homogenization treatment. The state adjusting pot 7 adjusts the viscosity and the flow rate of the homogenized molten glass Gm. A plurality of stirring pots 6 may be provided in parallel in a direction from the upstream side to the downstream side of the transfer device 3 (hereinafter referred to as a transfer direction).

The molding means 4 has a molded body 11 in which the molten glass Gm is made to flow down in a strip shape by an overflow down draw method, and a large-diameter introduction pipe 12 for guiding the molten glass Gm to the molded body 11. The introduction pipe 12 is supplied with molten glass Gm from the state adjusting pot 7 of the transfer device 3 via the small diameter pipe 13.

Next, a method of manufacturing a glass plate using the manufacturing apparatus 1 having the above configuration will be described. As shown in FIG. 2, the method for manufacturing a glass plate is roughly classified into a melting step S1, a clarification step S2, and a molding step S3.

The melting step S1 is a step of heating a glass raw material in the melting furnace 2 to generate molten glass Gm. The clarification step S2 is a step of supplying the molten glass Gm produced in the melting step S1 to the clarification tube 5 to perform a clarification treatment. The molding step S3 is a step of molding the glass ribbon Gr using the molten glass Gm that has undergone the clarification step.

As a feature of the glass plate manufacturing apparatus 1 having the above configuration and the manufacturing method thereof, as shown in FIG. 1, the clarification pipe 5 is inclined so as to be in a higher position as it moves to the downstream side, and The inclination angle α of the clear pipe 5 with respect to the horizontal axis is 0.25 ° to 5 °. The inclination angle α of the clarification pipe 5 is smaller than the inclination angle β of the first connecting pipe 8 with respect to the horizontal axis. The clarification tube 5 is made of a precious metal such as platinum or a platinum alloy. The first connection pipe 8, the second connection pipe 9, the stirring pot 6, the cooling pipe 10, the state adjustment pot 7, the small diameter pipe 13, and the introduction pipe 12 are also made of a precious metal such as platinum or a platinum alloy. ..

[First Embodiment]
FIG. 3 is a vertical sectional front view showing a glass plate manufacturing apparatus 1 according to the first embodiment of the present invention and a clarification tube 5 which is a main component of the manufacturing method thereof, and FIG. 4 is a vertical sectional front view showing AA of FIG. It is a vertical sectional side view cut according to a line. As shown in FIG. 3, the clarification tube 5 includes a cylindrical portion 5p inclined at the angle α described above, a pair of flange portions 5f formed at both ends of the tubular portion 5p in the transfer direction, and a pair of flange portions 5f. An electrode portion 5e integrally formed on the outer peripheral portion (upper portion in the present embodiment) is provided. The clarification tube 5 is energized and heated by applying a voltage to the electrode portion 5e. Then, by changing the voltage applied to the electrode portion 5e, the temperature of the molten glass Gm in the clarification tube 5 is adjusted. The clarification tube 5 is filled with molten glass Gm without forming a gas phase space. The molten glass Gm in the clarification tube 5 is heated to, for example, 1450 ° C to 1650 ° C. Foam Bu is contained in the molten glass Gm, and a vent portion 14 for discharging the foam Bu is provided at the upper portion of the downstream end portion of the clarification pipe 5.

Further, in the clarification pipe 5, partition plates 15 are arranged at a plurality of locations (four locations in the figure) in the transfer direction. As shown in FIG. 4, the partition plate 15 is an annular member fixed to the inner surface 5i of the tubular portion 5p, and a missing portion 15x is provided on the upper portion of the annular member 15. The bubble Bu in the molten glass Gm in the clarification pipe 5 passes through the missing portion 15x, moves toward the downstream side, and then is discharged from the vent portion 14.

More specifically, since the inclination angle α of the clarification tube 5 is 0.25 ° or more, the bubbles Bu generated and floating in the molten glass Gm in the clarification tube 5 do not stagnate and are indicated by arrows in FIG. As shown, it moves smoothly toward the downstream side while contacting the upper part of the inner surface 5i of the tubular portion 5p. For example, when the tilt angle α is 0.25 °, the bubble Bu moves at 0.1 m / h, and when the tilt angle α is 0.5 °, the bubble Bu moves at 0.4 m / h. When the inclination angle α is 1 °, the bubble Bu moves at 1.5 m / h. All or substantially all of the moved bubbles Bu are discharged from the vent portion 14 as shown by the arrow a in the figure. Therefore, it is possible to avoid a situation in which foam Bu is stagnant in the clarification pipe 5 and a gas pool is generated. On the other hand, if the inclination angle α of the clarification tube 5 is less than 0.25 °, the moving speed of the bubble Bu is insufficient, and the bubble Bu stagnates in the clarification tube 5. For example, when the inclination angle α is 0 °, the bubbles Bu stay at substantially the same position and stagnate, so that the moving speed of the bubbles is about 0 m / h. The gas pool formed by the stagnant foam Bu oxidizes the upper part of the inner surface 5i of the tubular portion 5p, and a large amount of precious metal foreign matter (platinum lumps or the like) is generated. Therefore, the quality of the manufactured glass plate is deteriorated and the product yield is also deteriorated. In the clarification pipe 5 in the present embodiment, the situation where the bubble Bu is stagnant can be avoided, so that such a problem is unlikely to occur.

Moreover, since the inclination angle α of the clarification pipe 5 in the present embodiment is 5 ° or less, the internal pressure of the clarification pipe 5 particularly near the inflow port 5a does not increase, and the clarification pipe 5 is less likely to be damaged or damaged. This improves the durability of the clarification pipe 5. On the other hand, when the inclination angle α of the clarification pipe exceeds 5 °, the internal pressure of the clarification pipe 5 particularly near the inflow port 5a increases, and the clarification pipe 5 is liable to be damaged or damaged.

From the above circumstances, according to the glass plate manufacturing apparatus 1 and the manufacturing method thereof according to the present embodiment, it is possible to prevent the foam Bu from stagnation in the clarification tube 5 and to prevent the internal pressure of the clarification tube 5 from increasing. It is possible to achieve a balance with things. In consideration of such circumstances, it is more preferable that the lower limit of the inclination angle α of the clarification pipe 5 is 0.5 °. Further, the upper limit value is more preferably 2 °.

[Second Embodiment]
FIG. 5 is a vertical sectional front view showing a glass plate manufacturing apparatus 1 according to a second embodiment of the present invention and a clarification tube 5 which is a main component of the manufacturing method thereof. The difference between the clarification pipe 5 in the second embodiment and the clarification pipe 5 in the first embodiment described above is that the vent portions 14 are provided at a plurality of locations (two locations in the figure) in the transfer direction of the clarification pipe 5. It is in the place where it was set up. The vent portion 14 of the plurality of vent portions 14 is provided at the downstream end portion of the clarification pipe 5.

When the amount of foam Bu is excessive, when attempting to discharge from one vent portion 14 as shown in FIG. 3, the foam Bu reaches the vent portion 14 continuously or intermittently, thereby causing the foam Bu to reach the vent portion 14 in the vicinity of the vent portion 14. The inner surface of the clarification tube 5 may be continuously or intermittently exposed to gas to oxidize. Even when the amount of foam Bu is excessive as described above, if a plurality of vent portions 14 are provided as in the second embodiment of FIG. 5, the amount of foam Bu discharged from one vent portion 14 is provided. Is reduced, so that the foam Bu reaches the vent portion 14 intermittently. Therefore, the time that the inner surface of the clarification pipe 5 around the vent portion 14 is exposed to the gas can be reduced, and the concern about oxidation can be eliminated. Since other configurations and actions and effects are the same as those of the above-described first embodiment, the components common to both embodiments are designated by the same reference numerals in FIG. 5, and the description thereof will be omitted.

[Third Embodiment]
FIG. 6 is a vertical sectional front view showing a clarification tube 5 which is a main component of the glass plate manufacturing apparatus 1 and the manufacturing method thereof according to the third embodiment of the present invention. The clarification pipe 5 in the third embodiment is different from the clarification pipe 5 in the second embodiment described above in that the clarification pipe 5 is the first pipe body 5B1 on the upstream side and the second pipe body 5B2 on the downstream side. It is in the place where it is composed of. The first tubular body 5B1 includes a first tubular portion 5p1, a pair of first flange portions 5f1 formed at both ends of the first tubular portion 5p1 in the transfer direction, and a pair integrally formed on the upper portion of these flange portions 5f1. The first electrode portion 5e1 of the above is provided. The second tubular body 5B2 is integrated with the second tubular portion 5p2, the pair of second flange portions 5f2 formed at both ends of the second tubular portion 5p2 in the transfer direction, and the upper part of the pair of second flange portions 5f2. It includes a pair of formed second electrode portions 5e2. An annular insulating member 16 is interposed between the first flange portion 5f1 and the second flange portion 5f2 that are adjacent to each other in the transfer direction. Although not shown, it is between the first flange portion 5f1 at the upstream end of the first pipe body 5B1 and the flange portion 8f at the downstream end of the first connecting pipe 8, and the second at the downstream end of the second pipe body 5B2. An annular insulating member is also interposed between the flange portion 5f2 and the flange portion 9f at the upstream end of the second connecting pipe 9. Further, vent portions 14 are provided at the downstream end portion of the first tubular portion 5p1 and the downstream end portion of the second tubular portion 5p2, respectively. Therefore, in this third embodiment, the clarification pipe 5 is divided into a first compartment region 5B1 which is the first pipe body and a second compartment region 5B2 which is the second pipe body, and each of these regions 5B1 and 5B2. The bubbles Bu in the molten glass Gm are discharged from each vent portion 14 in each of the regions 5B1 and 5B2 while being energized and heated. Since other configurations and actions and effects are the same as those of the second embodiment described above, the components common to both embodiments are designated by the same reference numerals in FIG. 6, and the description thereof will be omitted. In this third embodiment, the clarification pipe 5 is divided into two sections, a first section area 5B1 and a second section area 5B2, but it may be divided into a plurality of three or more section areas. .. In this case, a vent portion may be provided for each of a plurality of three or more compartmentalized areas, but at least the vent portion is provided only in the most downstream compartmentalized area or the most downstream compartmentalized area. May be good.

Although the method for manufacturing a glass plate and the manufacturing apparatus 1 according to the embodiment of the present invention have been described above, the present invention is not limited to this, and various variations are possible without departing from the gist thereof.

For example, in the above embodiment, the main purpose of the partition plate 15 is to reinforce the tubular portion 5p of the clarification pipe 5, but the main purpose is to stir the molten glass Gm instead of a part or all of the partition plate 15. A partition plate may be used.

1 Glass plate manufacturing equipment 2 Melting furnace 3 Transfer device 4 Molding means 5 Clarifying pipe 5B1 First compartment area 5B2 Second compartment area 5Ba Upstream compartment area 5Bb Downstream compartment area 5Bc Upstream compartment area 14 Vent part Bu Bubble Gm Molten glass Gr glass Ribbon S1 Melting process S2 Clarification process S3 Molding process α Tilt angle

Claims (4)

A melting step of heating a glass raw material to produce molten glass, a clarification step of supplying the molten glass produced in the melting step to a clarification tube made of a noble metal to perform a clarification treatment, and a molten glass having undergone the clarification step. It is a method for manufacturing a glass plate including a molding process for forming a glass ribbon using the glass ribbon.
The glass plate is characterized in that the clarification tube is tilted so as to be in a higher position as it moves to the downstream side, and the inclination angle of the clarification tube with respect to the horizontal axis is 0.25 to 5 °. Production method. The method for manufacturing a glass plate according to claim 1, wherein vent portions for discharging bubbles generated in the molten glass are provided at a plurality of locations in the direction from the upstream side to the downstream side of the clarification tube. Claim 1 is characterized in that the clarification pipe is divided into a plurality of compartments in a direction from the upstream side to the downstream side, and each compartment is provided with a vent portion for discharging bubbles generated in the molten glass. The method for manufacturing a glass plate according to. A melting furnace that heats a glass raw material to produce molten glass, a clarification tube made of precious metal that clarifies the molten glass produced by the melting furnace, and a glass ribbon using the molten glass that has been clarified. A glass plate manufacturing apparatus equipped with a molding means for forming a glass plate.
The glass plate is characterized in that the clarification tube is tilted so as to be in a higher position as it moves to the downstream side, and the inclination angle of the clarification tube with respect to the horizontal axis is 0.25 to 5 °. Manufacturing equipment.

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