JPH11302029A - Method for transporting ribbon-like glass and production of sheet glass - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stabilize the production process and to improve the yield by executing production in such a manner that a film of vapor exists between ribbon-like glass and a support for supporting the ribbon-like glass at the time of transportation and that the vapor is formed by the evaporation of the liquid existing in the support. SOLUTION: The molten glass melted in a melting furnace in a float method is supplied from the left side into a molten metal bath 3 where the glass is smoothed and flattened on molten metal 2 and the thickness thereof is regulated, to form the ribbon-like glass 1. The ribbon-like glass 1 is drawn out of the molten metal bath 3 and is transported to the form of riding on a hydrophilic porous carbon roll 5 which is the ribbon-like glass support. The film of the vapor exists between the ribbon-like glass 1 and the roll 5. Water is preferable as a vapor film forming material. The space is so partitioned by a shielding plate 6 as to prevent the intrusion of the generated vapor into the upper space 4 in the molten metal bath where the generated vapor is held at a reducing atmosphere. The ribbon-like glass 1 is thereafter transported to a annealing furnace 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel method for transporting ribbon-shaped glass and a method for manufacturing a sheet glass using the method.

[0002]

2. Description of the Related Art At present, the most widespread sheet glass manufacturing method is to melt a predetermined raw material in a melting furnace to form a molten glass, then introduce the molten glass into a molten metal bath, and use a mechanical external force to apply a vertical and horizontal width to the molten metal bath. Extend and move in the direction to make ribbon-shaped glass,
Thereafter, it is conveyed to a slow cooling kiln and cooled to obtain a sheet glass having a smooth surface, which is a so-called float method. The adoption of the float method significantly improved the smoothness of the surface of the sheet glass and eliminated the necessity of the polishing step, which had been indispensable until then, as compared with the other sheet glass manufacturing methods such as the roll-out method. Therefore, it has become the mainstream of the method for producing a smooth and transparent sheet glass. On the other hand, the roll-out method is a sheet glass manufacturing method in which a molten glass is passed between a pair of upper and lower forming rolls to form a ribbon-shaped glass, which is then conveyed to a slow cooling kiln and cooled. The roll-out method is still used as a method most suitable for producing glass with a pattern, fire-resistant glass sandwiching a metal wire or a net, or the like.

In the float method, a ribbon-shaped glass formed in a molten metal bath is drawn out of the molten metal bath and then conveyed by a roll to a lehr. Also in the roll-out method, the ribbon-shaped glass formed by roll-out is transported to the annealing furnace by a roll. The ribbon-shaped glass is also conveyed by rolls in an annealing furnace, and cooled from about the annealing point to near normal temperature.

[0004]

However, the above method has some disadvantages and problems, and an improvement is desired. That is, in the float method, the temperature of the ribbon-shaped glass formed and drawn out of the molten metal bath must be lower than the softening point in order to maintain the smoothed and flattened surface properties on the molten metal bath. On the other hand, when the formed ribbon-shaped glass is drawn from the molten metal bath, it has to cross the wall of the refractory bath constituting the molten metal bath. Therefore, near the outlet of the molten metal bath, the temperature of the formed ribbon-shaped glass must be equal to or higher than the glass transition point in order to repair the deformation that occurs when crossing the wall of the refractory tank.

If the temperature of the ribbon-shaped glass near the outlet of the molten metal bath is set to a high temperature, that is, about the softening point, the solidification of the ribbon-shaped glass does not proceed, and when the ribbon-shaped glass is drawn out of the molten metal bath and transported. A defect called "roller imprint" occurs upon contact with the roll. The disadvantage is that irregularities on the roll surface are transferred to the ribbon glass. Conversely, if the temperature of the ribbon-shaped glass near the outlet of the molten metal bath is set to a low temperature, that is, about the glass transition point, the solidification of the ribbon-shaped glass proceeds excessively, and the ribbon-shaped glass is easily cracked or broken. , In addition, scratches are caused by contact with the roll,
This often led to trouble in later processes. Therefore, it has been very difficult to control the temperature of the ribbon-shaped glass and roll near the outlet of the molten metal bath.

[0006] Also, in the roll-out method, defects and troubles due to contact with the roll, which are essentially the same as in the case of the float method, are likely to occur. Further, defects and troubles caused by the contact with the rolls in the annealing furnace were likely to occur. SUMMARY OF THE INVENTION The present invention has been made to solve a problem caused by contact between a ribbon-shaped glass, in particular, a high-temperature ribbon-shaped glass and a transfer roll, in a manufacturing process of a sheet glass.

[0007]

SUMMARY OF THE INVENTION The present invention relates to a method of transporting a ribbon of glass at a temperature lower than its softening point, wherein a ribbon glass and a support for supporting the ribbon glass during transportation are provided. A method of transporting a ribbon-like glass produced by evaporation of a liquid (hereinafter referred to as a vapor film-forming agent) in which a vapor film is present and the vapor present inside the support, a ribbon-like glass formed by a float method, A sheet glass manufacturing method of drawing from a molten metal bath using the method of transporting the ribbon-shaped glass and transporting it to a slow cooling kiln, and gradually reducing a ribbon-shaped glass formed by a roll-out method using the method of transporting the ribbon-shaped glass. Provided is a method for manufacturing a sheet glass to be transported to a cold kiln.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, a ribbon-shaped glass whose temperature is lower than the softening point comes into contact with a vapor film existing between the support and its support, and is conveyed without direct contact with the support. Is done. Therefore, there is little possibility that defects or troubles occur due to the contact between the ribbon-shaped glass and the support. The deformation of the ribbon-shaped glass during transfer poses a problem, so the temperature of the ribbon-shaped glass must be lower than the softening point.

[0009] The vapor is generated by evaporation of a liquid (hereinafter referred to as a vapor film forming agent) existing inside the support. Evaporation of the vapor film forming agent may occur on a surface of the support close to the ribbon-shaped glass (hereinafter referred to as a contact surface) or may occur inside the support near the contact surface. The amount of heat required for evaporation is supplied from hot ribbon glass. From this viewpoint, the higher the temperature of the ribbon-shaped glass, the better. It is preferably at least 300 ° C., more preferably at least the glass transition point.

[0010] The vapor film forming agent is supplied to the inside of the support so as to balance the amount of generated steam. The vapor film forming agent is not particularly limited as long as it is a substance that evaporates by heating with a high-temperature ribbon glass, and various organic and inorganic liquids can be used. However, it is preferred that the vapor does not chemically react with the glass to such an extent as to impair the glass quality, is thermally stable at the ribbon-like glass transport temperature, and is nonflammable. Further, in order not to lower the operability of the supply to the support, the boiling point of the vapor film forming agent is preferably less than 300 ° C, more preferably less than 200 ° C. In view of the above points, it is particularly preferable to use water or water-based materials which are chemically stable, have no toxicity, are easy to handle, and are inexpensive. The temperature of the vapor film forming agent when supplied to the support is not particularly limited as long as it is equal to or lower than the boiling point.

The support of the ribbon glass in the present invention is not particularly limited as long as it does not adversely affect the ribbon glass and the working atmosphere. A material through which a vapor film forming agent can permeate is preferred. The material of the support is preferably a material that has a high affinity for the vapor film forming agent and can wet the vapor film forming agent and include a sufficient amount of the vapor film forming agent inside the support. This is because the amount of the support that can contain the vapor film forming agent determines the amount of generated steam. That is, if the amount that can include the vapor film forming agent is too small,
If the amount of generated steam temporarily becomes excessive, the vapor film forming agent inside the support may be temporarily depleted and the generation of steam may be interrupted.

As the material of the support, a porous body that can appropriately transmit the vapor film forming agent and appropriately include the vapor film forming agent is preferably used. The porous body referred to here has a structure that can contain the vapor film forming agent therein and can appropriately transmit the vapor film forming agent, and the gaps of the fibrous structure become substantially pores. Is included. In order for the vapor film forming agent to be able to permeate properly, the diameter of the pores of the porous body is preferably 5 mm or less, more preferably 1 mm or less.
The thickness is particularly preferably 100 μm or less.

As specific support materials, for example, polymer materials derived from natural products such as cellulose, paper, wood, bamboo and the like, synthetic polymer materials such as polyolefin, and carbon materials can be used. Ni-Cr used for metal filters, etc.
-Al alloy, Fe-Cr-Al alloy, and other metal materials can also be used. Also, metal oxides such as aluminum oxide and zirconium oxide, metal carbides such as silicon carbide,
A ceramic material containing a metal nitride such as silicon nitride as a main component can also be used. When water is used as the vapor film forming agent, it is preferable to use a material that has been subjected to a hydrophilic treatment. Among them, hydrophilic porous carbon is excellent as a support material in terms of water permeability, an amount capable of containing water, mechanical strength, and the like.

The surface of the support is desirably very smooth except for holes or fibrous irregularities in the support. Generally, any surface can be used without problems as long as it can be formed and finished industrially at low cost. As a support, the contact surface is not fixed,
It is preferable to use a rotatable roll having such advantages.

In the present invention, the vapor film existing between the ribbon glass and the support is renewed by continuous supply of the vapor. As a result, there is little possibility that impurities or the like remain in the vapor film in contact with the ribbon-shaped glass, and a sheet glass with good surface smoothness can be obtained. Since the vapor film forming agent is supplied to the support in a liquid state, continuous supply is easy and the supply amount may be small.

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows an embodiment of the present invention in a float method. Molten glass melted in a melting furnace is supplied to a molten metal bath 3 from the left side of the figure, and is smoothed and flattened on the molten metal 2 and has a thickness. It is adjusted and formed into a ribbon-shaped glass 1. The ribbon-shaped glass 1 is withdrawn from the molten metal bath 3,
It is transported on a hydrophilic porous carbon roll 5 which is a ribbon-shaped glass support of the present invention. Ribbon glass 1
Although not shown, there is a vapor film between the and the hydrophilic porous carbon roll 5. Further, the space is partitioned by a shielding plate 6 so that the generated steam does not enter the upper space 4 in the molten metal bath kept in the reducing atmosphere. The ribbon-shaped glass 1 is further conveyed to the annealing furnace 7.
In the example shown in this figure, the material other than the hydrophilic porous carbon roll 5 may be any material and structure known in the float process, and is not limited at all.

FIG. 2 shows an example of the structure of the hydrophilic porous carbon roll 5 used in the example shown in FIG. 8 is a roll shaft, 9 is a water supply port, and 10 is a drain port. Here, the roll body is made of cylindrical hydrophilic porous carbon, and water as a vapor film forming agent is supplied and discharged. The illustrated one is a schematic diagram of the most common and simple structure, but is not limited in any way as long as the liquid-state vapor film forming agent can be continuously supplied and discharged.

FIG. 3 shows an embodiment of the present invention in a roll-out method. A molten glass 11 melted in a melting furnace is formed into a plate shape by a forming roll 12 to form a ribbon-shaped glass 1. In some cases, the pattern is ribbon-shaped glass 1
Is applied to the surface. The ribbon-shaped glass 1 is made of a hydrophilic porous carbon roll 5 which is the ribbon-shaped glass support of the present invention.
It is transported in the form of riding. Although not shown, a vapor film is present between the ribbon-shaped glass 1 and the hydrophilic porous carbon roll 5. The ribbon-shaped glass 1 is further conveyed to the annealing furnace 7.

In FIGS. 1 and 3, the case where the present invention is used for transporting ribbon-shaped glass from immediately after molding to entering a slow cooling kiln has been described. However, the present invention is not limited to this. It can also be used to transport ribbon-shaped glass near the cold kiln entrance. As described above, the present invention is a method for manufacturing a glass sheet which is currently widely used in industry, in a float method or a roll-out method, in which a transfer roll and a ribbon-shaped glass in a transfer step at a high temperature immediately after molding. The present invention provides a technique for solving a problem caused by contact and can be widely used for industrial production of sheet glass.

[0020]

According to the present invention, it is possible to solve various problems caused by the contact between a ribbon-shaped glass, particularly a high-temperature ribbon-shaped glass and a transporting roll, in a manufacturing process of a sheet glass. Significant cost reduction can be achieved through improvement of the yield based on stability and reduction of defects on the glass surface.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing an embodiment of the present invention.

FIG. 2 is a view showing a hydrophilic porous carbon roll of the present invention.

FIG. 3 is a side sectional view showing another embodiment of the present invention.

[Explanation of symbols]

 1: ribbon-shaped glass 2: molten metal 3: molten metal bath 4: upper space in the molten metal bath 5: hydrophilic porous carbon roll 6: shielding plate 7: annealing furnace 8: roll shaft 9: water supply port 10: drainage Mouth 11: Molten glass 12: Roll for forming

Claims (6)

[Claims] 1. A method of transporting a ribbon-shaped glass at a temperature lower than its softening point, wherein a film of vapor exists between the ribbon-shaped glass and a support that supports the ribbon-shaped glass during transportation. A method of transporting ribbon-shaped glass in which vapor is generated by evaporation of a liquid (hereinafter referred to as a vapor film forming agent) existing inside the support. 2. The method according to claim 1, wherein the support is made of a material through which the vapor film forming agent can pass. 3. The method according to claim 1, wherein the support is a roll. 4. The method according to claim 1, wherein said vapor film forming agent is water.
Or the method for transporting ribbon-shaped glass according to 3. 5. A method for manufacturing a glass sheet, comprising drawing a ribbon-shaped glass formed by a float method from a molten metal bath using the ribbon-shaped glass transportation method according to claim 1, 2, 3 or 4, and transporting the drawn glass to an annealing furnace. . 6. A method for manufacturing a glass sheet, comprising transporting a ribbon-shaped glass formed by a roll-out method to an annealing furnace using the ribbon-shaped glass transportation method according to claim 1, 2, 3 or 4.