WO2014091814A1

WO2014091814A1 - Plate glass production method and plate glass production device

Info

Publication number: WO2014091814A1
Application number: PCT/JP2013/077126
Authority: WO
Inventors: 哲史瀧口; 高弘木下
Original assignee: 旭硝子株式会社
Priority date: 2012-12-11
Filing date: 2013-10-04
Publication date: 2014-06-19
Also published as: JP2016028986A; TW201425241A; KR20150095616A; CN104797538A

Abstract

A plate glass production method that continuously supplies molten glass from a spout lip on to molten tin inside a float bath, and causes the molten glass that has been caused to be in contact with a tile to flow on to the molten tin, said tile provided below the spout lip with a space therebetween. The plate glass production method: heats the tile, using a heat-generating body provided between the spout lip and the tile and provided further on the upstream side than the tile surface in contact with the molten glass; and blows an inert gas into the gap between the spout lip and the tile.

Description

Sheet glass manufacturing method and sheet glass manufacturing apparatus

The present invention relates to a plate glass manufacturing method and a plate glass manufacturing apparatus.

The plate glass manufacturing apparatus continuously supplies molten glass onto molten tin in a float bath, and flows it in the downstream direction to form a strip-shaped glass ribbon. The space in the float bath is divided into a main space on the downstream side and a spout space on the upstream side by a partition wall (front lintel). The main space is much larger than the spout space and is filled with reducing gas to prevent oxidation of molten tin.

This plate glass manufacturing apparatus supplies molten glass onto the molten tin in the float bath via a spout trip arranged in the spout space. The molten glass supplied on the molten tin forms a main flow (front flow) that flows in the downstream direction and a tributary flow (back flow) that flows backward toward the tiles that are spaced below the spout trip. The molten glass on the molten tin is heated by a heating element embedded in the tile (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2007-131525

If the heating element is embedded in the tile, the components of the heating element may elute into the molten glass when the tile is eroded by molten glass or molten tin. In addition, when the heating element is embedded in the tile, it is difficult to replace only the heating element.

Therefore, it is conceivable to install a heating element outside the tile. In this case, components evaporated from the molten glass adhere to the surface of the heating element. If this deposit falls on the molten glass on the molten tin, it will cause cracks and defects in the glass. In addition, when a heating element is installed outside the tile, the heating element reacts with the surrounding atmosphere and gradually deteriorates.

The present invention has been made in view of the above-described problem, and is a method for producing a plate glass that can suppress the deposits of the heating element from falling onto the molten glass on the molten tin and can suppress deterioration of the heating element. And it aims at providing the manufacturing apparatus of plate glass.

In order to solve the above problems, a method for producing a plate glass according to an aspect of the present invention includes:
A molten glass is continuously supplied from a spout trip onto molten tin in a float bath, and the molten glass brought into contact with tiles provided at intervals below the spout trip is caused to flow on the molten tin. A manufacturing method comprising:
Heating the tile using a heating element provided between the spout trip and the tile, provided upstream of the contact surface with the molten glass in the tile,
In addition, an inert gas is blown into a gap space between the spout trip and the tile.

Moreover, the manufacturing apparatus of the plate glass by other one aspect | mode of this invention is the following.
A spout trip that continuously supplies molten glass onto the molten tin in the float bath;
Tiles that are provided below the spout trip and spaced apart, and that contact the molten glass supplied from the spout trip;
A heating element provided between the spout trip and the tile, provided upstream of a contact surface with the molten glass in the tile;
An inert gas supply unit that blows an inert gas into a gap space between the spout trip and the tile is provided.

According to one aspect of the present invention, there is provided a plate glass manufacturing method and a plate glass manufacturing apparatus capable of suppressing the fall of the deposits of the heating element to the molten glass on the molten tin and suppressing the deterioration of the heating element. Is done.

It is sectional drawing which shows the principal part of the manufacturing apparatus of the plate glass in 1st Embodiment. It is a top view which shows typically the flow of the molten glass on the molten tin of FIG. It is sectional drawing which shows the principal part of the manufacturing apparatus of the plate glass in 2nd Embodiment.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. In the drawings, the same or corresponding components are denoted by the same or corresponding reference numerals, and description thereof is omitted. In each drawing, the arrow A direction represents the downstream direction, and the arrow B direction represents the upstream direction.

(First embodiment)
FIG. 1 is a cross-sectional view showing a main part of a sheet glass manufacturing apparatus according to the first embodiment. FIG. 2 is a plan view schematically showing the flow of molten glass on the molten tin in FIG.

As shown in FIG. 1, the sheet glass manufacturing apparatus continuously supplies a molten glass 30 onto the molten tin 20 in the float bath 10, and causes the supplied molten glass 30 to flow on the molten tin 20 to form a strip plate shape. The glass ribbon 30A is formed. The formed glass ribbon 30 A is pulled up from the molten tin 20 in the downstream area of the float bath 10, transported into a slow cooling furnace, slowly cooled, and then cut into a predetermined size to form a plate glass.

The space 11 in the float bath 10 is partitioned by a partition wall (front lintel) 17 into a downstream main space 111 and an upstream spout space 112. The main space 111 is sufficiently larger than the spout space 112.

The main space 111 is supplied with reducing gas in order to prevent oxidation of the molten tin 20. The reducing gas may be, for example, a mixed gas of nitrogen gas and hydrogen gas, and contains 85% to 98.5% by volume of nitrogen gas and 1.5% to 15% by volume of hydrogen gas.

The reducing gas supply unit 60 that supplies the reducing gas to the main space 111 is configured by holes or the like provided in the ceiling 12 that forms the ceiling surface of the main space 111.

The plate glass manufacturing apparatus is provided with a spout trip 14 that continuously supplies the molten glass 30 onto the molten tin 20 in the float bath 10, and a space below the spout trip 14, and is supplied from the spout trip 14. The tile 15 which contacts the molten glass 30 is provided. The spout trip 14 and the tile 15 are installed on the front wall 13 of the float bath 10. The spout trip 14 and the tile 15 are made of a refractory material such as alumina or zirconia.

Spout lip 14, the tile 15, and side walls 16 extending from the tile 15 obliquely, ZrO ₂ 97% 85% or less by weight, the balance consists of hot melt refractory is a glassy mainly containing SiO ₂ It is preferable. The hot-melt refractory is obtained by melting and recrystallizing a refractory raw material at a high temperature. ZrO _{2 as a} hot-melt refractory mainly exists as badelite crystals. The remainder of the hot-melt refractory is glassy mainly composed of SiO ₂ , exists at the grain boundaries of ZrO ₂ baderite crystals, and densifies the hot-melt refractory. This glassy material includes Al ₂ O _{3 in} addition to SiO _2.
, Na ₂ O, P ₂ O _{5 and the} like can be contained in a small amount. This hot-melt refractory is excellent in heat resistance, can suppress the generation of bubbles due to reaction with the molten glass 30, and can also suppress fine streaks generated in the flow direction of the glass ribbon 30A. This is effective when the molten glass is alkali-free glass, particularly alkali-free glass containing boric acid.

As a specific example of the alkali-free glass, by mass percentage display based on oxide,
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%
MgO + CaO + SrO + BaO: 8% to 29.5%
ZrO ₂ : 0% to 5%
An alkali-free glass containing

When considering the solubility with a high strain point, preferably, by mass percentage display on the oxide basis,
SiO ₂ : 58% to 66%
Al ₂ O ₃ : 15% to 22%
B ₂ O ₃ : 5% to 12%
MgO: 0% to 8%
CaO: 0% to 9%
SrO: 3% to 12.5%
BaO: 0% to 2%
MgO + CaO + SrO + BaO: 9% to 18%
An alkali-free glass containing

Especially when considering the high strain point, preferably, by mass percentage display based on oxide,
SiO ₂ : 54% to 73%
Al ₂ O ₃ : 10.5% to 22.5%
B ₂ O ₃ : 0% to 5.5%
MgO: 0% to 8%
CaO: 0% to 9%
SrO: 0% to 16%
BaO: 0% to 2.5%
MgO + CaO + SrO + BaO: 8% to 26%
An alkali-free glass containing

In the present embodiment, the spout trip 14, the tile 15, the left side wall 16, and the right side wall 16 are all made of the hot melt refractory, but not all of the hot melt refractory. Also good. If at least one is comprised with the said hot-melt refractory, the said effect can be acquired to some extent or more.

A lateral wall for preventing the molten glass 30 from spilling left and right from the spout trip 14 may be disposed on both the left and right sides of the molten glass 30 flowing on the spout trip 14. When the lateral wall is provided, the spout trip 14 including the lateral wall is referred to.

The flow rate of the molten glass 30 supplied from the spout trip 14 onto the molten tin 20 is adjusted by the twill 19. As shown in FIG. 2, the molten glass 30 supplied from the tip 142 of the spout trip 14 onto the molten tin 20 flows backward to the main flow 31 (front flow) flowing in the downstream direction and upstream toward the tile 15. A tributary (back flow) 32 is formed.

Since the tributary 32 includes a portion that has been in contact with the spau trip 14, it includes bubbles generated by the reaction with the spau trip 14. The tributary flow 32 flows backward toward the tile 15, and then flows separately along the tile 15. Each of the tributaries 32 divided into the left and right flows along the side wall 16 extending obliquely from the tile 15, and merges with the end portion in the width direction of the main stream 31. Therefore, bubbles can be collected at the end in the width direction of the glass ribbon 30A, and a product with few defects can be cut out from the center in the width direction of the glass ribbon 30A.

Side walls 16 extend obliquely from the tiles 15 so that the tributaries 32 divided on the left and right sides can easily join the ends of the main stream 31 in the width direction. The side wall 16 extends obliquely toward the outer side in the width direction as it goes downstream.

As shown in FIG. 1, the sheet glass manufacturing apparatus includes a heating element 40 that heats the tile 15 in order to improve the fluidity of the tributary 32 that flows backward in the upstream direction and stabilize the flow of the tributary 32. The heating element 40 is provided between the spout trip 14 and the tile 15, and the molten glass 30 on the molten tin 20 is also heated by heating the tile 15.

The heating element 40 may heat the molten glass 30 around the tile 15 at a temperature 10 ° C. to 50 ° C. higher than the devitrification temperature of the glass. Glass devitrification around the tile 15 can be prevented.

The heating element 40 is provided between the spout trip 14 and the tile 15 and provided outside the tile 15. Therefore, when the tile 15 is eroded by the molten glass 30 or the molten tin 20, the components of the heating element 40 and the deposits of the heating element 40 are not eluted into the molten glass 30 or the molten tin 20. In addition, only the heating element 40 can be replaced.

The heating element 40 is provided on the upstream side of the contact surface 152 with the molten glass 30 in the tile 15. That is, the heating element 40 is provided at a position that does not overlap the molten glass 30 on the molten tin 20 in a top view. Therefore, the deposits of the heating element 40 are unlikely to fall on the molten glass 30 on the molten tin 20, and the glass is not easily broken or defective. The heating element 40 may be moved by an appropriate driving device or manually according to the erosion of the tile 15.

The heating element 40 is formed of a material having excellent corrosion resistance against reducing gas. The material of the heating element 40 is not particularly limited, and examples thereof include silicon carbide (SiC), a composite material of silicon carbide (SiC) and metal silicon (Si), and silicon nitride (Si ₃ N ₄ ). The heating element 40 may be coated with a ceramic material such as alumina.

The heating element 40 is rod-shaped and may be provided in parallel to the contact surface 152 of the tile 15 with the molten glass 30. The tributary 32 tends to flow from side to side along the tile 15.

The heating element 40 may be positioned inside the outer edge 154 (see FIG. 2) of the tile 15 as viewed from above, and may be shorter than the tile 15. The heating efficiency of the tile 15 is good.

The heating element 40 has an open porosity (JIS (Japanese Industrial Standard) R 1634) of preferably 15% or less, and more preferably 10% or less. If the open porosity exceeds 15%, the surface area of the heating element 40 exposed to the surrounding atmosphere is too large and the heating element 40 is likely to deteriorate.

The heating element 40 is preferably cylindrical and has an outer diameter of 20 mm to 40 mm. If it is a rectangular tube shape, local heat generation is likely to occur, and deterioration tends to occur. Moreover, the raw material cost of the heat generating body 40 will increase that it is not hollow but solid. Furthermore, if the outer diameter is larger than 40 mm, a large installation space is required. On the other hand, when the outer diameter is smaller than 20 mm, when the heat generation amount of the heating element 40 is the same, the outer surface temperature of the heating element 40 is too high, and the heating element 40 is likely to deteriorate.

The sheet glass manufacturing apparatus further includes a first inert gas supply unit 50 that blows an inert gas into the gap space 113 between the spout trip 14 and the tile 15. Nitrogen gas, argon gas, or the like is used as the inert gas blown into the gap space 113. By blowing inert gas into the gap space 113, the atmosphere around the heating element 40 can be inactivated, and deterioration of the heating element 40 can be suppressed. In addition, by blowing inert gas into the gap space 113, the concentration of hydrogen chloride gas in the atmosphere around the heating element 40 can be reduced, and deterioration of the heating element 40 due to the hydrogen chloride gas can be suppressed.

The hydrogen chloride gas is generated by the reaction between the chlorine gas evaporated from the molten glass 30 and the hydrogen gas supplied to the main space 111. The reason why the chlorine gas evaporates from the molten glass 30 is that chloride may be contained in the glass raw material as an inevitable impurity.

The concentration of hydrogen chloride gas in the atmosphere at a position 10 mm away from the outer surface of the heating element 40 is preferably 150 ppm or less in volume ratio. When the concentration of the hydrogen chloride gas exceeds 150 ppm by volume, the heating element 40 tends to deteriorate.

The first inert gas supply unit 50 may continuously blow inert gas into the gap space 113. The blowing amount is preferably 2 Nl (normal liters) / min to 15 Nl / min per 1 m of the rod-like heating element 40. When there is too much blowing amount of inert gas, the molten glass 30 on the molten tin 20 will be cooled, and the fluidity | liquidity of the tributary 32 will be impaired. On the other hand, if the amount of inert gas blown is too small, the effect of inactivating the atmosphere around the heating element 40 cannot be obtained sufficiently.

In addition, although the 1st inert gas supply part 50 of this embodiment blows inactive gas continuously in the crevice space 113, it may blow in discontinuously.

The first inert gas supply unit 50 may be composed of an inert gas supply pipe that is at least partially exposed to the gas in the float bath 10. The inert gas supply pipe 50 is warmed by the high-temperature gas in the float bath 10, and the inert gas flowing inside the inert gas supply pipe 50 is preheated. Since the preheated inert gas is blown into the gap space 113, the temperature fluctuation of the gap space 113 is small, and the temperature fluctuation of the molten glass 30 is small.

It should be noted that an inert gas previously heated to a predetermined temperature may be introduced into the inert gas supply pipe 50.

The inert gas supply pipe 50 is made of a material having excellent corrosion resistance against reducing gas, and is made of a ceramic material such as alumina.

The inert gas supply pipe 50 is provided at a position below the spout trip 14 and above the tile 15. The inert gas supply pipe 50 may be provided on the upstream side of the contact surface 152 with the molten glass 30 in the tile 15. That is, the inert gas supply pipe 50 may be provided at a position that does not overlap the molten glass 30 on the molten tin 20 in a top view. When the inert gas supply pipe 50 is broken, the broken material is unlikely to fall on the molten glass 30, and the glass is not easily broken or defective. The inert gas supply pipe 50 may be moved by an appropriate driving device or manually according to the erosion of the tile 15.

A plurality (for example, a pair) of inert gas supply pipes 50 may be provided so as to blow inert gas from both sides of the gap space 113, for example. The outlet 54 provided at the tip of the inert gas supply pipe 50 may be provided outside the gap space 113, and the inert gas may be blown into the gap space 113 by wind pressure.

In addition, although the blower outlet 54 of this embodiment is provided outside the gap space 113, it may be provided in the gap space 113. Moreover, although the blower outlet 54 of this embodiment is provided in the front-end | tip of the inert gas supply pipe | tube 50, you may provide in the middle.

The air outlet 54 of the inert gas supply pipe 50 may be installed at a position above the heating element 40. This is because the inert gas blown out from the blowout port 54 is colder and heavier than the gas in the gap space 113 and thus forms a flow from the top to the bottom after being blown out from the blowout port 54.

The plate glass manufacturing apparatus further includes a second inert gas supply unit 70 that supplies an inert gas to the upper space 114 above the spout trip 14 in the spout space 112. As the inert gas supplied to the upper space 114, nitrogen gas, argon gas, or the like is used. The hydrogen concentration in the upper space 114 can be reduced, and deterioration of the coating layer due to hydrogen gas can be suppressed when the twill 19 and the spout trip 14 are coated with platinum or a platinum alloy.

The second inert gas supply unit 70 may continuously blow the inert gas into the upper space 114 or may blow it discontinuously.

Similar to the first inert gas supply unit 50, the second inert gas supply unit 70 can be configured by an inert gas supply pipe that is at least partially exposed to the gas in the float bath 10. . The inert gas supply pipe is warmed by the high-temperature gas in the float bath 10, and the inert gas flowing through the inert gas supply pipe is preheated. Since the preheated inert gas is blown into the upper space 114, the temperature fluctuation of the upper space 114 is small, and the temperature fluctuation of the molten glass 30 is small.

(Second Embodiment)
The present embodiment relates to a modification of the first inert gas supply unit that supplies the inert gas to the gap space 113.

FIG. 3 is a cross-sectional view showing a main part of a sheet glass manufacturing apparatus according to the second embodiment. As shown in FIG. 3, the first inert gas supply unit 50 A blows an inert gas into the gap space 113, thereby forming an inert gas flow in the vicinity of the heating element 40. Therefore, reducing gas and hydrogen chloride gas are unlikely to approach the heating element 40, and deterioration of the heating element 40 can be suppressed. Moreover, the component evaporated from the molten glass 30 is unlikely to approach the heating element 40, and the generation of deposits on the heating element 40 can be suppressed.

It is desirable that the flow of the inert gas formed in the vicinity of the heating element 40 is a downward flow from the heating element 40. This is because when the flow from the heating element 40 toward the molten glass 30 on the molten tin 20 is formed, the inert gas constituting the flow is colder than the surrounding gas, and thus the fluidity of the tributary 32 is impaired. In addition, when a flow from the heating element 40 toward the molten glass 30 on the molten tin 20 is formed, the deposit on the heating element 40 is carried to the molten glass 30 on the molten tin 20.

The first inert gas supply unit 50A may be configured by an inert gas supply pipe that is at least partially exposed to the gas in the float bath 10 or the like. The inert gas supply pipe 50 A may be moved by an appropriate driving device or manually according to the movement of the heating element 40 accompanying the erosion of the tile 15.

In the present embodiment, unlike the first embodiment, the outlet 54A of the inert gas supply pipe 50A is provided in the gap space 113. For example, as shown in FIG. 3, the air outlet 54 A is located obliquely above the heating element 40 and blows out an inert gas toward the upper side of the heating element 40. The inert gas blown out from the blowout port 54A is colder and heavier than the gas in the gap space 113, and thus forms a flow from the top to the bottom after being blown out from the blowout port 54A. Thus, an inert gas flow is formed in the vicinity of the heating element 40.

In the present embodiment, the outlet 54A is located obliquely above the heating element 40, but the present invention is not limited to this. For example, the air outlet 54 A may be positioned above the heating element 40 and blow out an inert gas toward the heating element 40.

The blower outlet 54A may be singular or plural. The plurality of outlets 54A may be arranged at regular intervals along the axial direction of the inert gas supply pipe 50A, or may be arranged at irregular intervals. In short, it is only necessary that the flow of inert gas can be formed in the region around the heating element 40 where the concentration of hydrogen gas or hydrogen chloride gas is high.

In addition, 50 A of 1st inert gas supply parts in this embodiment can be used instead of the 1st inert gas supply part 50 in 1st Embodiment.

(Example 1)
In Example 1, an alkali-free glass plate was manufactured using the plate glass manufacturing apparatus shown in FIG. Nitrogen gas was used as the inert gas blown into the space between the spout trip and the tile. The amount of nitrogen gas blown was 6 Nl / min per 1 m length of the cylindrical heating element. Silicon carbide was used as the material of the heating element.

Incidentally, the spout lip, tiles, and left and right side walls of which extend from the tile obliquely, the ZrO ₂ 94 wt%, a SiO ₂ 4% by weight, _Al 2 _{O 3} 1 wt%, the Na ₂ O 0.3 wt% Consists of hot melt refractories contained.

As a result, in Example 1, an alkali-free glass plate could be continuously produced without replacing the heating element for 6 weeks. The concentration of hydrogen chloride gas in the atmosphere at a position 10 mm below the outer surface of the center in the longitudinal direction of the heating element was measured with a hydrogen chloride detector tube (manufactured by Komyo Chemical Co., Ltd., Tube No. 173SA (20-1200 ppm)). As a result, the volume ratio was 150 ppm.

(Comparative Example 1)
In Comparative Example 1, an alkali-free glass plate was produced in the same manner as in Example 1 except that the inert gas was not blown into the space between the spout trip and the tile.

As a result, in Comparative Example 1, the new heating element abnormally generated heat due to porosity in two weeks, and it was necessary to replace the heating element. The concentration of hydrogen chloride gas in the atmosphere at a position 10 mm below the outer surface at the center in the longitudinal direction of the heating element was 500 ppm by volume.

As mentioned above, although the embodiment etc. of the manufacturing apparatus of a plate glass, and the manufacturing method of a sheet glass were demonstrated, this invention is not limited to the said embodiment etc., The summary of this invention described in the claim. Within the range, various modifications and improvements are possible.

This application claims priority based on Japanese Patent Application No. 2012-270385 filed with the Japan Patent Office on December 11, 2012. The entire contents of Japanese Patent Application No. 2012-270385 are incorporated herein by reference. To do.

DESCRIPTION OF SYMBOLS 10 Float bath 11 Space 111 in float bath Main space 112 Spout space 113 Crevice space 114 Upper space 14 Spout trip 15 Tile 152 Contact surface 154 with molten glass in tile Tile outer edge 16 Side wall 17 diagonally extending from tile (partition wall) Front lintel)
20 Molten Tin 30 Molten Glass 30A Glass Ribbon 40 Heating Element 50 First Inert Gas Supply Portion 54 Outlet 60 Reducing Gas Supply Portion 70 Second Inert Gas Supply Portion

Claims

A molten glass is continuously supplied from a spout trip onto molten tin in a float bath, and the molten glass brought into contact with tiles provided at intervals below the spout trip is caused to flow on the molten tin. A manufacturing method comprising:
Heating the tile using a heating element provided between the spout trip and the tile, provided upstream of the contact surface with the molten glass in the tile,
Moreover, the manufacturing method of plate glass which blows inactive gas in the clearance gap between the said spout trip and the said tile.
The method for producing a plate glass according to claim 1, wherein the inert gas is blown into the gap space to form a flow of the inert gas in the vicinity of the heating element.
The method for producing plate glass according to claim 1 or 2, wherein at least a part of an inert gas supply pipe for blowing the inert gas into the gap space is exposed to the gas in the float bath.
The method for producing a plate glass according to any one of claims 1 to 3, wherein an amount of the inert gas blown into the gap space is 2 Nl / min to 15 Nl / min per 1 m of the rod-shaped heating element.
The method for producing a plate glass according to any one of claims 1 to 4, wherein the open porosity of the heating element is 15% or less.
6. The heating element according to claim 1, wherein the heating element has a rod shape, is disposed in parallel to a contact surface with the molten glass in the tile, and is located inside the outer edge of the tile in a top view. The manufacturing method of plate glass as described in any one of Claims 1-3.
The method for producing a plate glass according to any one of claims 1 to 6, wherein the heating element has a cylindrical shape and an outer diameter of 20 mm to 40 mm.
The space in the float bath is partitioned by a partition wall into an upstream spout space where the spout trip is provided, and a downstream main space,
The plate glass production according to any one of claims 1 to 7, wherein a reducing gas is supplied to the main space, and an inert gas is supplied to an upper space above the spout trip in the spout space. Method.
Side walls extending obliquely from said tile, said spout lip, and at least one of said tiles, ZrO 2 97% 85% or less by weight, the thermal melting refractory remainder being glassy mainly containing SiO 2 The method for producing a plate glass according to any one of claims 1 to 8, wherein the method comprises a product.
A spout trip that continuously supplies molten glass onto the molten tin in the float bath;
Tiles that are provided below the spout trip and spaced apart, and that contact the molten glass supplied from the spout trip;
A heating element provided between the spout trip and the tile, provided upstream of a contact surface with the molten glass in the tile;
An apparatus for producing plate glass, comprising: a first inert gas supply unit that blows an inert gas into a gap space between the spaw trip and the tile.
The plate glass manufacturing apparatus according to claim 10, wherein the first inert gas supply unit blows the inert gas into the gap space to form a flow of the inert gas in the vicinity of the heating element.
The apparatus for producing plate glass according to claim 10 or 11, wherein the first inert gas supply unit includes an inert gas supply pipe at least partially exposed to the gas in the float bath.
The plate glass manufacturing apparatus according to any one of claims 10 to 12, wherein an amount of the inert gas blown into the gap space is 2 Nl / min to 15 Nl / min per 1 m of the length of the rod-shaped heating element.
The plate glass manufacturing apparatus according to any one of claims 10 to 13, wherein the heating element has an open porosity of 15% or less.
The heating element according to any one of claims 10 to 14, wherein the heating element has a rod shape, is disposed in parallel to a contact surface with the molten glass in the tile, and is located inside the outer edge of the tile in a top view. The manufacturing apparatus of the plate glass as described in any one of.
The plate glass manufacturing apparatus according to any one of claims 10 to 15, wherein the heating element has a cylindrical shape and an outer diameter of 20 mm to 40 mm.
A partition wall that partitions the space in the float bath into a downstream main space and an upstream spout space;
A reducing gas supply unit for supplying reducing gas to the main space;
The plate glass manufacturing apparatus according to any one of claims 10 to 16, further comprising: a second inert gas supply unit configured to supply an inert gas to an upper space above the spout trip in the spout space.
Side walls extending obliquely from said tile, said spout lip, and at least one of said tiles, ZrO 2 97% 85% or less by weight, the thermal melting refractory remainder being glassy mainly containing SiO 2 The plate glass manufacturing apparatus according to any one of claims 10 to 17, which is made of a product.