JP7159972B2 - Molten glass conveying device, glass manufacturing device and glass manufacturing method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a molten glass conveying apparatus, a glass manufacturing apparatus, and a glass manufacturing method.

A glass manufacturing apparatus includes a melting apparatus, a refining apparatus (including a vacuum degassing apparatus and a high temperature refining apparatus), a forming apparatus, and a molten glass conveying apparatus connecting these apparatuses.

Platinum or a platinum alloy is often used as a material for the molten glass conveying device. Platinum or a platinum alloy has a high melting point, is a heat-resistant metal with excellent heat resistance, and has a lower reactivity with molten glass than other heat-resistant metals. In addition, it has excellent oxidation resistance at high temperatures and can ensure a certain degree of strength even at high temperatures.

However, depending on the composition of the glass, many bubbles may be generated when the molten glass comes into contact with a platinum material made of platinum or a platinum alloy. The bubbles are caused by oxygen generated by the dissociation of water contained in the molten glass upon contact with the platinum material or by electrolysis induced by the current flowing through the molten glass. formed by If air bubbles remain in the manufactured glass, there is a possibility that the quality of the glass will be deteriorated.

As a method for preventing the generation of such bubbles, Patent Document 1 discloses providing a capsule surrounding at least one container so that the hydrogen partial pressure around the non-glass contacting surface of the container is maintained at a certain level or higher. , a closed-loop controller for controlling the partial pressure of hydrogen in the capsule.

Japanese Patent Publication No. 2008-539160

However, capsules and closed-loop controllers are costly, with both high investment and operating costs to build them.
Moreover, the temperature of the gas such as water vapor supplied to the surroundings of the non-glass-contacting surface of the container is about 120 to 150° C. at most. Therefore, the outer surface of a platinum or platinum alloy conduit (about 1300 to 1500° C.) filled with molten glass is cooled by contact with the gas, and a temperature difference occurs in the molten glass in the conduit. This causes a difference in the saturated oxygen solubility of the molten glass in the conduit, and when an electrical circuit is formed there, oxidation-reduction occurs in which oxygen dissolves on the one hand and oxygen bubbles are generated on the other hand. There is a concern that the quality of the glass will deteriorate due to these oxygen bubbles.

The present invention has been made in view of the above circumstances, and a molten glass conveying apparatus capable of suppressing glass manufacturing costs while suppressing bubbles generated from molten glass inside a conduit made of platinum or a platinum alloy, An object of the present invention is to provide a glass manufacturing apparatus and a glass manufacturing method.

The present invention provides a molten glass conduit structure including at least one conduit made of platinum or a platinum alloy, a first ceramic structure provided around at least one of the conduits, and the first and a third ceramic structure provided between the first ceramic structure and the second ceramic structure. , the third ceramic structure relates to a molten glass conveying device having a gas flow path, and a gas of 200° C. or higher is supplied to the gas flow path.

ADVANTAGE OF THE INVENTION According to the molten-glass conveying apparatus which concerns on this invention, glass-manufacturing cost can be held down, suppressing the bubble which generate|occur|produces from the molten glass inside the conduit|pipe which consists of platinum or a platinum alloy.

FIG. 1 is a cross-sectional view showing a molten glass conveying device according to one embodiment of the present invention. FIG. 2 is a schematic diagram for explaining the gas supply system in the II section of the conduit structure for molten glass in FIG. 3A and 3B are enlarged cross-sectional views of the first ceramic structure, the second ceramic structure and the third ceramic structure shown in FIG. 2 is a diagram showing the configuration of a gas flow path in FIG. FIG. 4 is a schematic cross-sectional view for explaining one form of the gas flow path in the third ceramic structure. FIG. 5 is a perspective view of the third ceramic structure for explaining one form of the gas flow path. FIG. 6 is a schematic cross-sectional view for explaining one form of the gas flow path in the third ceramic structure. FIG. 7 is a schematic cross-sectional view for explaining one form of gas flow paths in the third ceramic structure. FIG. 8 is a diagram showing a glass manufacturing apparatus according to the first embodiment of the invention. FIG. 9 is a diagram showing a glass manufacturing apparatus according to a second embodiment of the invention. FIG. 10 is a diagram showing a glass manufacturing apparatus according to a third embodiment of the invention.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. In this specification, "-" representing a numerical range means a range including the numerical values before and after it.

[Molten glass transport device]
FIG. 1 is a cross-sectional view showing a molten glass conveying device according to one embodiment of the present invention. FIG. 2 is a schematic diagram for explaining the gas supply system in the II section of the conduit structure for molten glass in the molten glass conveying apparatus shown in FIG.

The molten glass conveying apparatus 1 includes a molten glass conduit structure 40, a first ceramics structure 10, a second ceramics structure 20, a bottom brick 22, a third ceramics structure 30, and a gas supply. a system 50;

The third ceramic structure 30 has gas flow paths (not shown in FIGS. 1 and 2) and supports the monolithic refractory material used for the first ceramic structure 10 . By connecting the supply pipes 54A to 54D and the exhaust pipes 56A and 56B in the gas supply system 50 to the third ceramic structure 30, the gas can be distributed throughout the gas flow path.

Molten glass conduit structure 40 includes at least one conduit made of platinum or a platinum alloy. In FIG. 1, the conduits that constitute the conduit structure 40 for molten glass are a main pipe 41 and branch pipes 42 and 43 . A first ceramic structure 10 is provided around these conduits, and a second ceramic structure 20 is provided around the first ceramic structure 10 . A third ceramic structure 30 is provided between the first ceramic structure 10 and the second ceramic structure 20 .

The molten glass conduit structure 40 has a main pipe 41 having a vertical center axis and two branch pipes 42 and 43 communicating with the main pipe 41 and having a horizontal center axis. One branch pipe 42 branches from the lower side of the main pipe 41 , and another branch pipe 43 branches from the upper side of the main pipe 41 . The main pipe 41 and the branch pipes 42 and 43 are both cylindrical, and the molten glass G flows through them. Molten glass G flows in from branch pipe 42 , flows upward through main pipe 41 , and flows out to branch pipe 43 . The two branch pipes only need to have different heights, and the molten glass flows in from the upper side of the main pipe 41, flows downward through the main pipe 41, and flows out to the lower side of the main pipe 41. may be provided as follows.

The conduits (main pipe 41 and branch pipes 42, 43) constituting the molten glass conduit structure 40 are made of platinum or a platinum alloy. Platinum alloys are, for example, platinum-gold alloys, platinum-rhodium alloys, platinum-iridium alloys. The conduit may also be made of platinum or a platinum alloy with metal oxide particles such as Al ₂ O ₃ , ZrO ₂ , Y ₂ O ₃ dispersed in strengthened platinum.

The molten glass conduit structure is not limited to the embodiment shown in FIG. 1, and may be composed of only one main conduit, or may be composed of two or more conduits, a main conduit and branch conduits. Also, the conduit covered with the first ceramic structure may be the main pipe or the branch pipe, or both the main pipe and the branch pipe may be covered.
Alternatively, a main pipe may be a conduit having a horizontal center axis. In this case, the molten glass conduit structure includes a first supply pipe 251, a second supply pipe 252, and a third supply pipe 253 shown in FIG. can be used for In addition, the conduit may not be extended in the horizontal direction but may be inclined, and may be a curved pipe as well as a straight pipe.

In FIG. 1, the main pipe 41 has a bottom wall 2 at its lower end. The bottom wall 2 may be provided with a discharge port for discharging part of the molten glass G to the outside. Moreover, the main pipe 41 may be provided with a lid member for preventing heat radiation from the molten glass G at the upper end.

The height of the molten glass G inside the main pipe 41 (hereinafter referred to as “molten glass level GL”) is higher than the upper ends of the branch pipes 43 . Therefore, the branch pipe 43 is entirely filled with the molten glass G inside. As a result, in the branch pipe 43, it is possible to prevent boric acid components and the like from evaporating from the surface layer of the molten glass and make the molten glass heterogeneous, thereby preventing defects such as reams from occurring in the glass.

The conduits (the main pipe 41 and the branch pipes 42, 43) constituting the molten glass conduit structure 40 preferably have an inner diameter of 50 mm or more, more preferably 100 mm or more. Also, the inner diameter is preferably 500 mm or less, more preferably 450 mm or less. Moreover, the thickness in the radial direction is preferably 0.1 mm or more, and preferably 3 mm or less. The height (axial length) of the main pipe 41 is preferably 500 mm or more, more preferably 800 mm or more. Also, the height is preferably 3000 mm or less, more preferably 2700 mm or less. Moreover, the axial length of the branch pipes 42 and 43 is preferably 50 mm or more, more preferably 150 mm or more. Also, the axial length is preferably 1500 mm or less, more preferably 1300 mm or less. When a plurality of branch pipes are included in the conduit structure for molten glass like the branch pipes 42 and 43, the sizes of the plurality of branch pipes may be the same or different.

In FIG. 1, a molten glass conduit structure 40 has two branch pipes 42 and 43 communicating with a main pipe 41 at one end thereof. The branch pipes 42 and 43 may communicate with another main pipe on the other end side.

Strictly speaking, the central axis of the main pipe 41 is not necessarily required to be vertical, and the central axis may be inclined to some extent with respect to the vertical direction. Similarly, the central axes of the branch pipes 42 and 43 are not necessarily required to be horizontal in a strict sense, and the central axes may be inclined to some extent with respect to the horizontal direction.

The main pipe 41 or the branch pipes 42 and 43 may have a bellows-like outer shape in which convex portions and concave portions that are continuous in the circumferential direction by 360 degrees are alternately provided along the axial direction.

The main pipe 41 may be provided with a stirrer for stirring the molten glass G inside. At least the portion of the stirrer that contacts the molten glass G is made of platinum or a platinum alloy.

The first ceramic structure 10 preferably has an air permeability of 1.0×10 ⁻¹³ m ² or more, more preferably 1.0×10 ⁻¹¹ m ² or more. Moreover, the air permeability is preferably higher than that of the second ceramic structure 20 . As used herein, the air permeability means a value measured according to the method described in JIS R 2115:2008.
When the permeability of the first ceramic structure 10 is 1.0×10 ⁻¹³ m ² or more, the gas flowing through the gas flow path in the third ceramic structure 30 permeates the first ceramic structure 10, The molten glass conduit structure 40 can be permeated with gas. Furthermore, since the gas permeability of the first ceramic structure 10 is higher than that of the second ceramic structure 20, the permeation of gas through the second ceramic structure 20 can be suppressed. can be reduced. In particular, when the permeability of the first ceramic structure 10 is 1.0×10 ⁻¹¹ m ² or more, heat insulating bricks preferably used for the second ceramic structure 20 (for example, SP15, RB180, both of which will be described later) (trade name, manufactured by Hinomaru Ceramics Co., Ltd.).

The average open porosity of the first ceramic structure 10 is preferably 20% or more, more preferably 25% or more, and preferably 60% or less, more preferably 50% or less. Here, the average open porosity can be obtained by measurement using the Archimedes method or a mercury porosimeter.
When the average open porosity is 20% or more, deterioration of thermal shock resistance of the first ceramic structure 10 can be prevented. Further, when the average open porosity is 60% or less, it is possible to prevent deterioration of corrosion resistance to the molten glass G.

Since the first ceramic structure 10 is provided around the molten glass conduit structure 40 filled with the molten glass G, the first ceramic structure 10 is particularly resistant to high temperature molten glass, specifically molten glass of 1450 ° C. or higher. Excellent corrosion resistance is preferred.

It is preferable that substantially no gap exists between the conduits (the main pipe 41 and the branch pipes 42 and 43 ) constituting the molten glass conduit structure 40 and the first ceramics structure 10 . Specifically, it is preferred that the gap is less than 0.5 mm. Thereby, the deformation of the conduit due to the expansion pressure applied from the molten glass G can be suppressed.

The thickness of the first ceramic structure 10 in the radial direction of the conduit is preferably 15 mm or more, more preferably 20 mm or more, and preferably 50 mm or less, and more preferably 40 mm or less. When the thickness is 15 to 50 mm, the gap between the conduit constituting the molten glass conduit structure 40 and the second ceramics structure 20 is filled with the slurry body to be the first ceramics structure 10 and sintered. It is excellent in workability when the first ceramic structure 10 is formed by arranging.

In the first ceramic structure 10, the gap between the conduit constituting the molten glass conduit structure 40 and the second ceramic structure 20 is filled with an amorphous ceramic material such as alumina castable. is preferred. With such a configuration, the conduit and the second ceramic structure 20 can move slightly relative to each other when the temperature changes, so that the conduit can be prevented from cracking. Alumina castable means a castable refractory mainly composed of alumina (Al ₂ O ₃ ), and the Al ₂ O ₃ content is preferably 90% by weight or more. A ceramic material containing 90% by mass or more of SiO ₂ or a ceramic material containing 60% by mass or more of ZrO ₂ can also be preferably used instead of alumina castable.

The second ceramic structure 20 preferably has an air permeability of 1.0×10 ⁻¹¹ m ² or less, more preferably less than 1.0×10 ⁻¹³ m ² . When the permeability of the second ceramic structure 20 is 1.0×10 ⁻¹¹ m ² or less, the permeation of gas through the second ceramic structure 20 can be suppressed, and the gas supply amount can be reduced. In particular, when the permeability of the second ceramic structure 20 is less than 1.0×10 ⁻¹³ m ² , the permeability is generally lower than that of the first ceramic structure 10, and the gas supply rate is increased. can be reduced efficiently.

For the second ceramic structure 20, heat insulating bricks mainly composed of at least one selected from the group consisting of alumina, magnesia, zircon and silica are preferably used. Specific examples include silica/alumina heat insulating bricks, zirconia heat insulating bricks, and magnesia heat insulating bricks. Commercially available products include SP-15 (manufactured by Hinomaru Ceramics Co., Ltd.), RB180 (manufactured by Hinomaru Ceramics Co., Ltd.), LBK3000 (manufactured by Isolite Industry Co., Ltd.), and the like.

The bottom bricks 22 are provided below the bottom wall 2 of the main pipe 41 and support the main pipe 41 and the first ceramic structure 10 and the third ceramic structure 30 provided around the main pipe 41 . The bottom brick 22 is preferably a heat-insulating brick mainly composed of at least one selected from the group consisting of alumina, magnesia, zircon and silica as a brick having excellent corrosion resistance. Specific examples include alumina-zirconium heat insulating bricks. Commercially available products include silica/alumina insulation bricks, ZM-C (manufactured by AGC Ceramics Co., Ltd.), RB180 (manufactured by Hinomaru Ceramics Co., Ltd.), and the like.

The molten glass conveying apparatus 1 may be provided with a first ceramic structure and a second ceramic structure in order from the top in the axial direction of the main pipe 41 instead of the bottom brick 22 . A third ceramic structure may be provided between the first ceramic structure and the second ceramic structure.

The third ceramic structure 30 is located between the first ceramic structure 10 and the second ceramic structure 20 and has a gas channel.

The third ceramic structure 30 has a gas channel, thereby suppressing the generation of bubbles (hereinafter referred to as “hydrogen permeable bubbles”) generated when the molten glass comes into contact with a conduit made of platinum or a platinum alloy. be able to. Hydrogen-permeable bubbles are more likely to occur as the hydrogen partial pressure difference between the inside and outside of the platinum conduit increases. On the other hand, by spreading the gas over the third ceramic structure 30 and the first ceramic structure 10, the hydrogen partial pressure outside the conduit is increased and the hydrogen partial pressure difference is reduced, thereby forming hydrogen permeable bubbles. be able to suppress it. Here, the hydrogen partial pressure inside the conduit increases as the amount of water contained in the molten glass increases (the β-OH value, which will be described later, increases).

From the viewpoint of allowing the gas to permeate the third ceramic structure 30, the permeability of the third ceramic structure 30 is preferably 1.0×10 ⁻¹² m ² or more, more preferably 1.0×10 ⁻¹¹ m ² or more. is more preferable, and 1.0×10 ⁻¹⁰ m ² or more is even more preferable.

The third ceramic structure 30 may or may not be in contact with the first ceramic structure 10 and the second ceramic structure 20 . Also, some regions may be in contact and other regions may be non-contact.
Since the third ceramic structure 30 is in contact with the first ceramic structure 10 and the second ceramic structure 20 in at least partial regions, deformation of the conduit due to expansion pressure applied from the molten glass G can be suppressed. .

When the third ceramic structure 30 is in contact with the first ceramic structure 10 and the second ceramic structure 20 in all regions, the gas flow path extends inside the third ceramic structure 30. It is formed (see FIG. 3A). In addition, when the entire area is non-contact, another member intervenes between the third ceramic structure 30 and the first ceramic structure 10 and the second ceramic structure 20, respectively. It means that it is distributed. Also, a gas flow path may be formed in at least part of the non-contact region of the third ceramic structure 30 .

Further, when the third ceramic structure 30 is in contact with the first ceramic structure 10 or the second ceramic structure 20 in a part of the region and out of contact with the other region, the non-contact A gas flow path may be formed in the third ceramic structure 30 in the region of (see FIG. 3B). Also, at the same time or instead of that, the separate member may be provided.

The third ceramic structure preferably has a thickness of 5 to 20 mm in the radial direction of the conduit. When the thickness is 5 to 20 mm, the gas permeation speed can be easily adjusted, and the gas can be efficiently spread over the third ceramic structure 30 .

3A and 3B are enlarged cross-sectional views of the first ceramic structure, the second ceramic structure and the third ceramic structure shown in FIG. 2 is a diagram showing the configuration of a gas flow path in FIG. 4, 6 and 7 are diagrams showing one form of the gas flow path in the third ceramic structure. FIG. 5 is a perspective view of the third ceramic structure for explaining one form of the gas flow path.

A third ceramic structure 30A shown in FIG. 3A has a gas flow path 32A inside. This is the form taken when the third ceramic structure is in contact with the first and second ceramic structures.
The third ceramic structure 30B shown in FIG. 3B is not in contact with part of the second ceramic structure 20, and has gas flow paths 32B in the non-contact region. Also, the third ceramic structure may be out of contact with a part of the first ceramic structure 10 and have a gas flow path in the non-contact region.

When the gas flow path is formed inside the third ceramic structure 30, the cross section of the gas flow path preferably has a rectangular shape with a side of 3 to 20 mm or a circular shape with a diameter of 3 to 20 mm. Also, the cross-sectional size of the gas flow path is preferably 5 to 400 mm ² .
When the gas flow path is formed on the surface of the third ceramic structure 30, the gas flow path has a groove shape. The shape of the gas flow path is not particularly limited, and may be a flat groove with a constant groove depth or a groove with an uneven groove depth. Grooves with uneven depth include, for example, triangular grooves and cylindrical grooves where the center of the groove is deeper than the sides of the groove, as well as shapes where the center of the groove is shallower than the sides of the groove. good. The groove width is preferably 3 to 20 mm, and the groove depth is preferably 3 to 20 mm.
The distance from one end of the gas channel to the end of the adjacent gas channel is preferably 10 mm to 100 mm.

From the viewpoint of suppressing the deformation of the conduit due to the expansion pressure applied from the molten glass, the third ceramic structure 30 has at least It is preferred to have partially contacting regions. Moreover, it is more preferable that the third ceramic structure 30 has a region at least partially in contact with both the first ceramic structure 10 and the second ceramic structure 20 .

The gas flow path of the third ceramic structure 30 is preferably formed along at least one of the circumferential direction and the axial direction of the conduit.
For example, as shown in FIG. 4, gas passages 32C and 32D are formed along the axial direction of the conduit. It is preferable that two or more gas flow paths are formed and spaced apart in the circumferential direction of the conduit. The gas flow path 32</b>C is formed in a region of the third ceramic structure 30 that is not in contact with the second ceramic structure 20 . The gas channel 32</b>D is formed in a region of the third ceramic structure 30 that is not in contact with the first ceramic structure 10 .
Also, the gas flow path 32E is formed along the circumferential direction of the conduit. It is preferable that two or more gas flow paths are formed and spaced apart in the axial direction of the conduit. The gas channel 32</b>E is formed in a region of the third ceramic structure 30 that is not in contact with the second ceramic structure 20 . That is, the gas flow path 32E is formed on the outer surface of the third ceramic structure 30 (boundary with the second ceramic structure 20).

The gas flow paths shown in FIG. 4 are composed of a gas flow path 32D formed in a region not in contact with the first ceramic structure 10 and a gas flow path 32D formed in a region not in contact with the second ceramic structure 20. 32 C of flow paths exist together.
Furthermore, the gas flow passages of the third ceramic structure 30 include a gas flow passage 32E formed along the circumferential direction of the conduit and gas flow passages 32C and 32D formed along the axial direction of the conduit. have.

3 is a perspective view of the third ceramic structure 30, showing an example of the case where the gas flow path is formed on the outer surface of the third ceramic structure 30, that is, in a region that is not in contact with the second ceramic structure 20. FIG. is shown in FIG.
In FIG. 5, two gas flow paths 32C are formed along the axial direction of the conduit and two gas flow paths 32E are formed along the circumferential direction of the conduit. Although both of these gas passages 32C and 32E are in communication, they may be independent from each other without being communicated with each other, and the gas may be supplied by connecting each gas passage to a supply pipe. In addition, communicating gas flow paths and independent gas flow paths may coexist.

The gas channel has two or more gas channels 32C or 32D formed along the axial direction of the conduit and two or more gas channels 32E or 32F (see FIG. 6) formed along the circumferential direction of the conduit. , and preferably communicate with each other to form a mesh-like gas flow path.
Also, the gas flow path may be spirally formed on the surface of the conduit.

In the third ceramic structure 30 shown in FIG. 6, a gas channel 32F is formed along the circumferential direction of the conduit in addition to the gas channel 32D. The gas flow path 32</b>F is formed in a region of the third ceramic structure 30 that is not in contact with the first ceramic structure 10 . That is, the gas flow path 32F is formed on the inner surface of the third ceramic structure 30 (boundary with the first ceramic structure 10). In this embodiment, the gas flow path 32D and the gas flow path 32F communicate with each other. In addition, communicating gas flow paths and independent gas flow paths may coexist.

When providing the gas flow path, as shown in FIG. 7, a member 60 may be further provided in at least a partial region between the third ceramic structure 30 and the first ceramic structure 10. FIG. The member 60 is provided so as to contact at least part of the first ceramic structure 10 and the third ceramic structure 30 and cover at least part of the gas flow path 32D.

The member 60 is a useful aspect when forming the first ceramic structure 10 after forming the molten glass conduit structure 40 and the third ceramic structure 30 in the manufacturing method of the molten glass conveying apparatus. In this case, the third ceramic structure 30 has a gas flow path 32</b>D formed in a region that is not in contact with the first ceramic structure 10 . The above aspect is also useful when the gas flow path 32F is formed together with the gas flow path 32D or instead of the gas flow path 32D. That is, even when the member 60 is provided so as to contact at least part of the first ceramic structure 10 and the third ceramic structure 30 and cover at least part of the gas flow path 32F, the above-mentioned Aspects are useful.

In such a manufacturing method, the molten glass conduit structure 40 and the third ceramics structure 30 are first formed, and the gap between them is filled with a slurry body to be the first ceramics structure, followed by sintering. to form the first ceramic structure 10 . The gas flow paths 32D and 32F are formed on the inner surface of the third ceramic structure 30, that is, the surface on the first ceramic structure 10 side. Therefore, when the slurry is filled, not only the gap but also the gas flow paths 32D and 32F are filled with the slurry, and there is concern that the gas flow paths 32D and 32F may be blocked. On the other hand, by covering part of the gas flow paths 32D and 32F with the member 60 to prevent the inflow of the slurry, it is possible to prevent the gas flow paths 32D and 32F from being clogged when the slurry is filled. .

The member 60 may cover not only the gas flow path in the third ceramic structure 30 but also other parts. Moreover, the member 60 may be provided in the entire region between the first ceramic structure 10 and the third ceramic structure 30. FIG. Note that the member 60 does not prevent gas permeation. Furthermore, since the member 60 is provided in such a manner as to cover the gas flow paths 32D and 32F, it does not prevent the gas from flowing through the gas flow paths.
The member 60 may be a member that melts and vaporizes at a high temperature when used in the molten glass conveying apparatus 1 . Moreover, it may be a member that remains without being melted or vaporized even at a high temperature. In this case, a ceramic film or a heat-resistant fiber can be preferably used. In the case of glass fiber, heat resistance means that the glass fiber has a softening point higher than the working temperature, and in the case of ceramic fiber, it means that the ceramic fiber has a melting point higher than the working temperature. do.

As the heat-resistant fibrous body, one containing glass fiber or ceramic fiber is preferable, or an aggregate of these fibers is preferable. Although the form is not particularly limited, a plurality of fibers may be woven into a cloth, or a plurality of fibers may be entangled in a mass. A heat-resistant fibrous body woven like a cloth is excellent in flexibility and workability. Therefore, it is possible to cover a wide range in such a manner as to conform to the shape of the molten glass conduit structure 40 and the first ceramic structure 10 .

The heat-resistant fiber body containing glass fiber or ceramic fiber contains 50% or more of SiO ₂ in terms of mass% based on oxide, and the slurry body that becomes the first ceramic structure 10 flows into the gas flow path. It is more preferable because it is possible to more effectively prevent it from occurring.

Similarly, the thickness of the member 60 is preferably 0.5 mm or more from the viewpoint of preventing the inflow of slurry. Moreover, if the thickness is too large, the strength of the first ceramic structure 10 or the third ceramic structure 30 may decrease, so the thickness is preferably 20 mm or less. In addition, the thickness of a member means the average value.

As shown in FIGS. 1 and 2, the molten glass conveying device 1 preferably further comprises a gas supply system 50 . The gas supply system 50 has a gas generator 51 that generates gas, a gas heater that heats the generated gas, and supply pipes 54A to 54D that supply the heated gas to the gas flow paths. Preferably, it further has exhaust pipes 56A and 56B for exhausting the gas that has passed through the gas passages.

1 and 2, the gas supply system 50 includes a gas generator 51 for generating gas, a control valve 52 for adjusting the flow rate of the gas, and a gas flow path for supplying the gas to the third ceramic structure 30. and two exhaust pipes 56A and 56B for exhausting the gas that has passed through the gas flow path of the third ceramic structure 30. As shown in FIG. By having a plurality of supply pipes 54A to 54D, the gas can be efficiently distributed to the gas flow paths of the third ceramics structure 30. FIG. In addition, in the gas supply system 50 , the number of supply pipes and exhaust pipes, installation locations, and the like can be appropriately changed according to the form of the gas flow path formed in the third ceramic structure 30 .

A boiler is used as the gas generator 51 to generate steam, for example. A gas cylinder filled with a desired gas can also be used together with the gas generator 51 or in place of it. A desired single gas or mixed gas can be supplied by these aspects.
Although the gas heating device is not shown, the generated gas is heated by the gas heating device and introduced into the gas flow path through the supply pipes 54A to 54D. The gas heater heats the gas supplied to the gas flow path to a temperature of 200° C. or higher.

One control valve 52 is preferably provided for each of the supply pipes 54A-54D, so that the amount of gas supplied to the supply pipes 54A-54D can be controlled independently.

The supply pipes 54A-54D pass through the second ceramic structure 20 and are connected to the gas flow paths of the third ceramic structure 30. As shown in FIG. Further, if the ends of the gas flow paths are visible from the outside, the supply pipes 54A to 54D may be directly connected to the gas flow paths without penetrating the second ceramic structure 20. FIG.
In FIG. 1 , the supply pipes 54A and 54B are positioned at the axial center of the main pipe 41 in the vertical direction. The supply pipes 54C and 54D are positioned axially below the main pipe 41 in the vertical direction. The horizontal positions of the supply pipes 54A and 54C are upstream in the molten glass G flow direction. The horizontal positions of the supply pipes 54B and 54D are downstream in the molten glass G flow direction. However, the arrangement of the supply pipes may be changed as appropriate depending on the gas flow path, and is not limited to the above configuration.

For example, the supply pipe may be positioned axially above the main pipe 41 in the vertical direction in FIG. Moreover, the horizontal position may be the upper side or the lower side in the vertical direction of the paper surface of FIG. 2 (the direction perpendicular to the flow direction of the molten glass G).

The temperature of the gas supplied to the gas flow path of the third ceramic structure 30 from the supply pipes 54A to 54D is 200° C. or higher. As a result, even when the inside of the conduit is filled with the molten glass G and is at a high temperature, it is possible to suppress the generation of bubbles due to electrolysis accompanying the cooling of the molten glass G in the conduit. The temperature of the gas supplied to the gas flow path is preferably 250° C. or higher.
Moreover, the temperature of the gas is preferably 600° C. or lower, more preferably 550° C. or lower, from the viewpoint of constructing the piping with a general-purpose metal such as stainless steel (SUS).

The type of gas is not particularly limited as long as the generation of bubbles due to the electrolysis can be suppressed, and examples include water vapor (H ₂ O), N ₂ , H ₂ , O ₂ , Ar, He, Ne, Xe, CO ₂ , CO, and the like. is mentioned. One of these gases may be used, or two or more may be used.

In addition to electrolysis, molten glass contains moisture, and this moisture is decomposed at the Pt interface forming the conduit to generate O ₂ and H ₂ , which also generates bubbles (oxygen). do. In order to suppress the generation of bubbles (oxygen), it is preferable to increase the hydrogen partial pressure outside the conduit so that hydrogen molecules (H ₂ ) do not pass through the conduit. In this way, in order to increase the hydrogen partial pressure outside the conduit, the gas supplied to the gas flow path preferably contains hydrogen atoms, and it is more preferable to use a gas containing at least _one of water vapor and H2. preferable.

Furthermore, from the viewpoint of suppressing oxidation of platinum or platinum alloy in the conduit to PtO ₂ , the gas supplied to the gas flow path preferably contains an inert gas such as N ₂ , Ar, He, Ne , Xe and CO ₂ more preferably. Further, it is more preferable to use a mixed gas further containing an inert gas in addition to the above gas containing hydrogen atoms.

The gas pressure supplied to the gas flow path of the third ceramic structure 30 by the supply pipes 54A to 54D is preferably 1 Pa to 24 kPa, more preferably 1 kPa or less, and even more preferably 50 Pa or less. When the gas pressure is 1 Pa or more, the gas can be sufficiently distributed in the gas flow path of the third ceramic structure 30 . Further, when the gas pressure is 24 kPa or less, the external pressure of the conduit such as the main pipe 41 does not become too high, and deformation of the conduit can be prevented.

The supply pipe shown in FIG. 2 branches into supply pipes 54A and 54B on the way from the gas generator 51 to the gas flow path of the third ceramic structure 30. As shown in FIG. It should be noted that the present invention is not limited to this form, and for example, a supply pipe connected to the gas generator 51 and the gas flow path of the third ceramic structure 30 may be provided independently without branching in the middle. .

The exhaust pipes 56A, 56B pass through the second ceramic structure 20 and are connected to the gas flow paths of the third ceramic structure 30, like the supply pipes 54A to 54D. Moreover, when the end of the gas flow path can be visually recognized from the outside, the exhaust pipe may be directly connected to the gas flow path without penetrating the second ceramic structure 20 .
In FIG. 1, the positions of the exhaust pipes 56A and 56B are axially above the main pipe 41 in the vertical direction. The horizontal position of the exhaust pipe 56A is upstream in the molten glass G flow direction. The horizontal position of the exhaust pipe 56B is downstream in the flow direction of the molten glass G. As shown in FIG. However, the arrangement of the exhaust pipes is changed as appropriate depending on the gas flow path, and is not limited to the above-described form.

For example, in FIG. 1, the exhaust pipe may be positioned at the axial center or lower portion of the main pipe 41 in the vertical direction. Moreover, the horizontal position may be the upper side or the lower side in the vertical direction of the paper surface of FIG. 2 (the direction perpendicular to the flow direction of the molten glass G).

The exhaust pipes 56A and 56B are preferably provided at positions lower than the height of the molten glass inside the main pipe 41 (the molten glass level GL). This is because if the exhaust pipe is provided at a position higher than the molten glass level GL, the internal pressure of the main pipe 41 becomes lower than the external pressure, and the main pipe 41 may be deformed.

Further, when the molten glass conduit structure 40 has at least one main pipe and at least one branch pipe, at least one of the supply pipe and the exhaust pipe is located at a position lower than the molten glass level GL inside the main pipe 41. It is preferably provided. It should be noted that the main pipe 41 here has a central axis in the vertical direction, and the branch pipe communicating with the main pipe 41 has a central axis in the horizontal direction.

The supply pipes 54A to 54D and the exhaust pipes 56A and 56B are insulating pipes having excellent heat resistance in the portions passing through the second ceramic structure 20 and the portions connected to the gas flow paths of the third ceramic structure 30. Preferably. Since the molten glass conduit structure 40 may be electrically heated, the use of insulating tubes can prevent current from flowing through the supply and exhaust tubes. A ceramic tube is preferably used as the insulating tube, and a specific example thereof includes a porcelain tube and the like.

The molten glass conveying apparatus 1 can distribute the gas at 200° C. or higher to the outside of the molten glass conduit structure 40 through the gas flow path of the third ceramic structure 30 . Therefore, generation of air bubbles due to electrolysis can be suppressed. Further, when a gas containing hydrogen atoms is used, the formation of hydrogen-permeable bubbles can be suppressed even when the glass is produced under the condition that the molten glass contains a large amount of water (high β-OH value, which will be described later). Furthermore, using a gas containing an inert gas can suppress PtO ₂ formation. Also, since there is no need to build a capsule and closed loop controller as shown in the prior art, both capital and operating costs are reduced.

[Glass manufacturing apparatus and glass manufacturing method]
(First embodiment)
FIG. 8 is a diagram showing a glass manufacturing apparatus according to the first embodiment of the invention. A glass manufacturing apparatus and a glass manufacturing method according to a first embodiment of the present invention will be described with reference to FIG. In FIG. 8, heat insulating materials such as heat insulating bricks disposed around the molten glass conveying devices 1 and 1A, the ascending pipe 202 and the descending pipe 203 and covering them are omitted.

A glass manufacturing apparatus 500 includes a melting apparatus 100, a vacuum degassing apparatus 200, a forming apparatus 300, and molten glass conveying apparatuses 1 and 1A. The molten glass conveying device 1A is provided between the melting device 100 and the vacuum degassing device 200 and connects the melting device 100 and the vacuum degassing device 200 . Further, the molten glass conveying device 1 is provided between the vacuum degassing device 200 and the molding device 300 and connects the vacuum degassing device 200 and the molding device 300 .

The melting apparatus 100 includes a melting tank 104 to which frit is supplied, and a burner 102 for melting the frit. The burner 102 mixes and burns a fuel such as natural gas or heavy oil with gas to form a flame, and heats the frit from above by radiating the flame toward the frit.

Here, a burner that mainly uses air as a gas is called an air-combustion burner, and a burner that mainly uses oxygen as a gas is called an oxy-combustion burner. Oxygen-fired burners are superior to air-fired burners in terms of high thermal efficiency and low _CO2 and _NOx emissions due to their smaller displacement. A plurality of burners 102 are preferably provided. All oxygen combustion burners may be used, or an oxygen combustion burner and an air combustion burner may be used in combination.

The vacuum degassing apparatus 200 includes a vacuum degassing tank 201 , an ascending pipe 202 , a descending pipe 203 and a vacuum housing 204 .

A cylindrical vacuum degassing tank 201 is accommodated in a vacuum housing 204 so that its long axis is oriented in the horizontal direction. A vertically oriented rising pipe 202 is attached to the lower surface of one end of the vacuum degassing tank 201, and a descending pipe 203 is attached to the lower surface of the other end. The riser tube 202 and the downcomer tube 203 are partially located within a vacuum housing 204 .

The ascending pipe 202 communicates with the vacuum degassing tank 201, and introduces the molten glass G from the melting tank 104 into the vacuum degassing tank 201 via the molten glass conveying device 1A. The downcomer pipe 203 communicates with the vacuum degassing tank 201 and guides the molten glass G after vacuum degassing to the molding apparatus 300 via the molten glass conveying device 1 . In the decompression housing 204, the decompression degassing tank 201, the ascending pipe 202, and the descending pipe 203 are surrounded by a heat insulating material such as heat insulating bricks for heat insulating coating.

Since the vacuum degassing tank 201, the ascending pipe 202, and the descending pipe 203 are conduits for molten glass, they are made of materials having excellent heat resistance and corrosion resistance to molten glass. For example, it is made of platinum, a platinum alloy, or a reinforced platinum made by dispersing metal oxides in platinum or a platinum alloy. It may also be made of a ceramic-based non-metallic inorganic material, that is, made of a dense refractory. Alternatively, a dense refractory lined with platinum or a platinum alloy may be used.

In the molding device 300, the molten glass G is molded to obtain molded glass having a predetermined shape. After being slowly cooled, the molded glass is cut and processed into products as required.

As the forming apparatus 300, a float forming apparatus or a fusion forming apparatus is used to obtain a glass sheet as a product. A float forming apparatus is a device that continuously supplies molten glass to the surface of molten tin in a bath and forms it into a strip shape. The fusion forming apparatus continuously supplies molten glass to the inside of a gutter having a substantially V-shaped cross section, and forms the molten glass into a strip shape by joining the molten glass overflowing from the gutter to the left and right sides at the lower edge of the gutter. It is a device.

As the molding apparatus 300, a molding apparatus using a blow method, a bellows method, a down-draw method, or a press method is used to obtain a glass container or a glass tube as a product.

The molten glass conveying device 1 corresponds to the molten glass conveying device 1 shown in FIG. The main pipe 41 is provided with a stirrer 44 for stirring the molten glass G inside. The branch pipe 42 is connected to the descending pipe 203 and conveys the molten glass G to the main pipe 41 . The branch pipe 43 is connected to the molding device 300 and conveys the molten glass G to the molding device 300 .

The molten glass conveying device 1A includes a main pipe 41A, branch pipes 42A and 43A, and a stirrer 44. The molten glass conveying apparatus 1A is provided with branch pipes 42A and 43A so that the molten glass G flows in from the upper side of the main pipe 41A, flows downward in the main pipe 41A, and flows out to the lower side of the main pipe 41A. Although different from the molten glass conveying apparatus 1, other apparatus configurations are common.

In the glass manufacturing apparatus 500, at least one of the molten glass conveying device 1 and the molten glass conveying device 1A should be provided with the third ceramics structure 30 and the gas supply system 50, and the other should be the third ceramics structure. A configuration without the structure 30 and the gas supply system 50 may also be used. A gas of 200° C. or higher is supplied to the gas flow path of the third ceramic structure 30 .

Instead of the vacuum degassing device 200, the glass manufacturing apparatus may use a high-temperature refining type refining device (hereinafter referred to as a "high-temperature refining device") (details will be described later as a second embodiment). In the high-temperature refining equipment, in order to remove bubbles efficiently, the temperature of the molten glass flowing through the refining tank is set as high as possible to lower the viscosity of the molten glass and increase the bubble growth rate to increase the diameter of the bubbles. , is a device that increases the floating speed of bubbles and operates so that bubbles can be removed.

In the glass manufacturing method according to the first embodiment of the present invention, a glass manufacturing apparatus 500 is used, frit is melted in a melting apparatus 100 to prepare a molten glass G, and the molten glass G is sent to a vacuum degassing apparatus 200. Then, the glass is defoamed by a molding apparatus 300 to obtain a molded glass having a predetermined shape. After the molded glass is slowly cooled, it is cut into products (for example, glass plates) as necessary.

(Second embodiment)
FIG. 9 is a diagram showing a glass manufacturing apparatus according to a second embodiment of the invention. A glass manufacturing apparatus and a glass manufacturing method according to a second embodiment of the present invention will be described with reference to FIG. Here, descriptions of portions of the melting device 100, the molding device 300, and the molten glass conveying device 1A that overlap with the description of the first embodiment will be omitted. In addition, FIG. 9 shows heat insulating bricks or the like disposed around the clarification device 250, the molten glass conveying device 1A, the first supply pipe 251, the second supply pipe 252 and the third supply pipe 253, and insulatingly covering them. Insulation is omitted.

The glass manufacturing apparatus 600 includes a melting apparatus 100, a clarification apparatus 250, a forming apparatus 300 and a molten glass conveying apparatus 1A. The molten glass conveying device 1A is preferably provided between the melting device 100 and the clarifying device 250 and/or between the clarifying device 250 and the forming device 300 .
The glass manufacturing method includes a melting step, a fining step and a forming step in this order, and between the melting step and the fining step and/or between the fining step and the forming step, a molten glass conveying step is provided. Including further. In the molten glass transfer step, the molten glass transfer device 1A is used to supply a gas of 200° C. or higher to the gas flow path of the third ceramic structure in the molten glass transfer device 1A.

In FIG. 9, the glass manufacturing apparatus 600 includes a melting apparatus 100, a clarification apparatus 250, a forming apparatus 300, a molten glass conveying apparatus 1A, a first supply pipe 251, a second supply pipe 252 and a third supply pipe 253.
The first supply pipe 251 connects the dissolving device 100 and the clarifying device 250 . The molten glass conveying device 1A is provided between the clarifying device 250 and the molding device 300 . The second supply pipe 252 connects the refining device 250 and the molten glass conveying device 1A. The third supply pipe 253 connects the molten glass conveying device 1A and the molding device 300 .

In the melting apparatus 100, the burner 102 heats the frit to obtain molten glass G at, for example, 1500.degree. C. to 1630.degree. Molten glass G in the melting tank 104 flows through the first supply pipe 251 and is supplied to the clarifier 250 .

In the clarifier 250, the temperature of the molten glass G is adjusted, and gas components contained in the molten glass G are removed. The finer 250 is preferably a hot finer. In this case, the molten glass G is heated to, for example, 1500.degree. C. to 1700.degree. The clarified molten glass G flows through the second supply pipe 252 and is supplied to the molten glass conveying device 1A.

In the molten glass conveying device 1A, the molten glass G is stirred by the stirrer 44, and the components of the molten glass G are homogenized. The temperature of the molten glass G in the main pipe 41A is, for example, 1250.degree. C. to 1450.degree. The viscosity of the molten glass G inside the main pipe 41A is, for example, 500 poise to 1300 poise. The homogenized molten glass G flows into the third supply pipe 253 , is cooled while the temperature is controlled in the process of flowing through the third supply pipe 253 , and is supplied to the forming apparatus 300 .

Although the branch pipes 42A and 43A of the molten glass conveying apparatus 1A are omitted in FIG. 9, the branch pipes 42A and 43A are connected to the second supply pipe 252 and the third supply pipe 253, respectively.

(Third embodiment)
FIG. 10 is a diagram showing a glass manufacturing apparatus according to a third embodiment of the invention. A glass manufacturing apparatus and a glass manufacturing method according to a third embodiment of the present invention will be described with reference to FIG. Here, descriptions of portions of the melting device 100, the molding device 300, and the molten glass conveying device 1A that overlap with the description of the first embodiment will be omitted. FIG. 10 omits heat insulating materials such as heat insulating bricks disposed around the molten glass conveying apparatus 1A, the first conveying pipe 111 and the second conveying pipe 112 and covering them.

The glass manufacturing apparatus 700 includes a melting device 100 , a molding device 300 , a molten glass conveying device 1A, a first conveying pipe 111 and a second conveying pipe 112 . Molten glass conveying device 1A is provided between melting device 100 and molding device 300 . The first conveying pipe 111 connects the melting device 100 and the molten glass conveying device 1A. The second conveying pipe 112 connects the molten glass conveying device 1A and the molding device 300 .

In the melting apparatus 100, the frit is heated by the burner 102, and the molten glass G is obtained. The molten glass G is subjected to a fining treatment in the melting tank 104 . Here, alkali-containing glass such as soda lime glass and alkali borosilicate glass is clarified in the dissolving tank 104 without the vacuum degassing device 200 of the first embodiment or the clarification device 250 of the second embodiment. is possible. The clarified molten glass G flows through the first transfer pipe 111 and is supplied to the molten glass transfer device 1A.

In the molten glass conveying device 1A, the molten glass G is stirred by the stirrer 44, and the components of the molten glass G are homogenized. The homogenized molten glass G flows into the second conveying pipe 112 , is cooled while the temperature is controlled in the course of flowing through the second conveying pipe 112 , and is supplied to the forming apparatus 300 .

Although the branch pipes 42A and 43A of the molten glass conveying apparatus 1A are omitted in FIG. 10, the branch pipes 42A and 43A are connected to the first conveying pipe 111 and the second conveying pipe 112, respectively.

(glass)
The glass manufactured by the glass manufacturing apparatus equipped with the molten glass conveying apparatus is cut and processed as necessary, and becomes a product such as a glass plate. When the glass plate as a product is used as a glass substrate for various displays, it is preferably an alkali-free glass substrate. Alkali-free glass refers to glass that does not substantially contain alkali metal oxides such as Na ₂ O and K ₂ O. “Substantially free” means that the total content of alkali metal oxides is 0.1% by mass or less.

The glass plate is expressed in mass% based on oxides,
_SiO2 : 54-66%
_Al2O3 : _10-23 %
_B2O3 : _0-12 %
MgO: 0-12%
CaO: 0-15%
SrO: 0-16%
BaO: 0-15%
MgO + CaO + SrO + BaO: 8-26%
It is preferably composed of alkali-free glass containing

The resulting glass preferably has a β-OH value of 0.15 to 0.5 mm ⁻¹ , more preferably 0.25 mm ⁻¹ or more, even more preferably 0.35 mm ⁻¹ or more. The β-OH value is a value used as an index of water content in glass.
When the β-OH value of the glass is 0.15 to 0.5 mm ⁻¹ , the bubbles contained in the molten glass in the vacuum degassing device and the clarification device are likely to grow, promoting defoaming and clarification. . Further, when the β-OH value is 0.35 mm ⁻¹ or more, the oxy-combustion ratio of burner combustion can be increased, and the production of exhaust gas can be suppressed, so that the operating cost of glass production can be reduced.

The β-OH value is the transmittance of a glass test piece that is formed into a plate shape from molten glass after defoaming or clarification, or a glass test piece that is cut from a glass container or the like and processed into a plate shape with a grinder. , measured using a Fourier transform infrared spectrophotometer (FT-IR), and can be obtained from the following formula.

β-OH value = (1/X) log ₁₀ (T ₁ /T ₂ )
X: glass plate thickness (mm)
T ₁ : Transmittance (%) at reference wave number 4000 cm ⁻¹
T ₂ : Minimum transmittance (%) near 3570 cm ⁻¹ of hydroxyl group absorption wave number

The β-OH value is governed by the water content in the glass raw material, the water vapor concentration in the dissolving tank, the burner combustion method (oxygen combustion, air combustion) in the dissolving tank, and the like. In particular, the β-OH value can be conveniently adjusted by adjusting the burner combustion method. Specifically, to increase the β-OH value, the oxy-combustion ratio of burner combustion is increased, and to decrease the β-OH value, the air-combustion ratio of burner combustion is increased.

When the glass plate is used as a cover glass for displays, it is preferably glass for chemical strengthening. Chemically strengthened glass obtained by chemically strengthening glass for chemical strengthening is used as a cover glass. In the chemical strengthening treatment, among the alkali ions contained in the glass surface, ions with a small ionic radius (such as Na ions) are replaced with ions with a large ionic radius (such as K ions), thereby compressing the glass surface to a predetermined depth. Form a stress layer.

When the glass plate is used as window glass or vehicle glass, it is preferably soda-lime glass.

When the glass as a product is used as a glass-made physical and chemical instrument such as a beaker or a heat-resistant cooking utensil such as a glass pot, it is preferably borosilicate glass.

The present invention will be further described below using examples and comparative examples. However, the present invention is not limited to these descriptions.

[Experimental Examples 1 and 2 and Comparative Example 1]
Using the glass manufacturing apparatus 500 shown in FIG. 8, bubbles generated when the amount of water in the molten glass is increased were evaluated for each temperature of the gas supplied to the gas flow path of the third ceramic structure. . The bubbles are generated when the molten glass comes into contact with the platinum material that is the conduit.

A molten glass conveying device 1 in a glass manufacturing apparatus 500 includes a first ceramic structure 10, a third ceramic structure 30 and a second ceramic structure 20 arranged in this order around a main pipe 41 and branch pipes 42 and 43. It is a structure provided by The gas flow paths in the third ceramic structure 30 are provided in a region that is not in contact with the first ceramic structure, and are 40 along the axial direction of the main pipe 41 and 15 along the circumferential direction of the main pipe 41. , respectively. Each gas channel communicates with each other. The gas flow paths are provided at a pitch of 20-70 mm.
The gas channels were flat grooves with a width of about 2 mm per channel. The depth of the groove is about 2 mm.

The air permeability of the first ceramic structure 10, the second ceramic structure 20 and the third ceramic structure 30 in the molten glass conveying device 1 is 5.7×10 ⁻¹³ m ² and 2.2×10 m 2 respectively. ⁻¹² m ² , 9.9×10 ⁻¹² m ² .

In the molten glass conveying apparatus 1 , water vapor was supplied to the gas flow path of the third ceramic structure 30 by the gas supply system 50 . Table 1 shows the supply temperature and supply pressure of steam at that time. In addition, in this embodiment, the molten glass conveying apparatus 1A does not include the third ceramic structure 30 and the gas supply system 50 .

The molten glass G is prepared by melting the frit of non-alkali glass composition in the melting tank 104, the molten glass G is degassed by the vacuum degassing device 200, and the molten glass is formed into a strip by the float method. The glass ribbon was slowly cooled and cut to obtain glass plates (Examples 1 and 2 and Comparative Example 1) having a thickness of 0.50 mm.

The glass compositions of Examples 1 and 2 and Comparative Example 1 are SiO ₂ : 59.8%, Al ₂ O ₃ : 17.2%, and B ₂ O ₃ : 7.8% in terms of % by mass based on oxides. , MgO: 3.1%, CaO: 4.1%, SrO: 7.7%, BaO: 0.1%, Cl: 0.2%.
The β-OH value of the obtained glass plate was determined by the method described above. Table 1 shows the results.

The obtained glass plate was irradiated with light from the side of the glass plate in a dark room, and the number of bubble defects exceeding 20 μm was examined by an edge light inspection in which the main surface of the glass plate was inspected, and the density of the bubble defects was calculated. did. Here, the density of bubble defects means the number of bubble defects per unit area (m ² ) on the main surface of the glass plate. Table 1 shows the results.

From the above results, according to the present invention, by setting the supply temperature of the gas supplied to the gas flow path to 200° C. or higher, the density of bubble defects with a size of more than 20 μm is lower than when the gas supply temperature is 120° C. was able to be reduced to 1/50.
It has been found that by suppressing the formation of the bubble defects, it is possible to effectively suppress deterioration in the quality of the resulting glass product.

Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.

Applications of the manufactured glass include construction, vehicle, liquid crystal display, organic EL display, cover glass, physics and chemistry equipment, cooking utensils, and other various uses.

1, 1A Molten glass conveying device 10 First ceramic structure 20 Second ceramic structure 22 Bottom bricks 30, 30A, 30B Third ceramic structures 32A to 32F Gas channel 40 Molten glass conduit structure 41 Main pipe 42, 43 Branch pipe 44 Stirrer 50 Gas supply system 51 Gas generator 52 Control valves 54A to 54D Supply pipes 56A, 56B Exhaust pipe 60 Member 100 Dissolution device 200 Vacuum degassing device 250 Clarification device 300 Molding device 500, 600, 700 Glass Manufacturing equipment G Molten glass GL Molten glass level

Claims (18)

a molten glass conduit structure including at least one conduit made of platinum or a platinum alloy;
a first ceramic structure provided around at least one of the conduits;
a second ceramic structure provided around the first ceramic structure;
a third ceramic structure provided between the first ceramic structure and the second ceramic structure;
The molten glass conveying apparatus, wherein the third ceramic structure has a gas flow channel, and a gas of 200° C. or higher is supplied to the gas flow channel. 2. The molten glass conveying apparatus of claim 1, wherein the gas is below 600<0>C. The molten glass conveying apparatus according to claim 1 or 2, wherein the gas is a gas containing hydrogen atoms. 4. The molten glass conveying apparatus according to claim 3, wherein said gas is a mixed gas further containing an inert gas. The molten glass conveying apparatus according to any one of claims 1 to 4, wherein the third ceramic structure has the gas flow path inside. The third ceramic structure is not in contact with at least a part of at least one of the first ceramic structure and the second ceramic structure, and the gas flow path is formed in the non-contact region. The molten glass conveying apparatus according to any one of claims 1 to 4, having The melt according to any one of claims 1 to 6, wherein the gas flow path is formed along at least one of a circumferential direction and an axial direction of at least one of the conduits. Glass transport equipment. 8. The molten glass conveying apparatus according to claim 7, wherein two or more gas flow paths are formed along the axial direction and are formed at intervals in the circumferential direction. The molten glass conveying apparatus according to claim 7 or 8, wherein two or more gas flow paths are formed along the circumferential direction and are formed at intervals in the axial direction. further comprising a member in at least a partial region between the first ceramic structure and the third ceramic structure;
10. The member is provided so as to contact the first ceramic structure and the third ceramic structure and cover at least part of the gas flow path. Molten glass conveying device according to. 11. The molten glass conveying apparatus according to claim 10, wherein the member contains glass fiber or ceramic fiber and has a _SiO2 content of 50% or more in terms of % by mass based on oxides. The molten glass conveying apparatus according to claim 10 or 11, wherein the member has a thickness of 0.5 mm or more. Furthermore, equipped with a gas supply system,
The gas supply system comprises a gas generator that generates gas, a gas heater that heats the generated gas, and a supply pipe that supplies the heated gas to the gas flow path. 13. The molten glass conveying apparatus according to any one of 1 to 12. 14. The molten glass conveying apparatus according to claim 13, wherein said gas supply system further has an exhaust pipe for exhausting said gas that has passed through said gas flow path. The conduit structure for molten glass has, as the conduit, at least one main pipe having a central axis in the vertical direction and at least one branch pipe communicating with the main pipe and having a central axis in the horizontal direction,
15. The molten glass conveying apparatus according to claim 14, wherein at least one of said supply pipe and said exhaust pipe is provided at a position lower than the height of the molten glass filling said main pipe. A glass manufacturing apparatus comprising a melting device, a refining device and a forming device,
Further comprising the molten glass conveying device according to any one of claims 1 to 15,
A glass manufacturing apparatus, wherein the molten glass conveying device is provided between the melting device and the clarification device and/or between the clarification device and the molding device. A glass manufacturing method comprising a melting step, a fining step and a forming step in this order,
Further comprising a molten glass conveying step between the melting step and the fining step and at least one between the fining step and the forming step,
In the molten glass transfer step, the molten glass transfer device according to any one of claims 1 to 15 is used, and a gas of 200 ° C. or higher is supplied to the gas flow path of the third ceramic structure in the molten glass transfer device. supply, glass manufacturing method. 18. The method of manufacturing glass according to claim 17, wherein the resulting glass has a β-OH value of 0.15 to 0.5 mm ⁻¹ .

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