CN115572045A - Float glass manufacturing device and float glass manufacturing method - Google Patents

Float glass manufacturing device and float glass manufacturing method Download PDF

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Publication number
CN115572045A
CN115572045A CN202210665970.8A CN202210665970A CN115572045A CN 115572045 A CN115572045 A CN 115572045A CN 202210665970 A CN202210665970 A CN 202210665970A CN 115572045 A CN115572045 A CN 115572045A
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CN
China
Prior art keywords
gas
glass ribbon
suction nozzle
float glass
nozzle
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Pending
Application number
CN202210665970.8A
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Chinese (zh)
Inventor
隅田和明
川崎直哉
三浦丈宜
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AGC Inc
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Asahi Glass Co Ltd
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Filing date
Publication date
Application filed by Asahi Glass Co Ltd filed Critical Asahi Glass Co Ltd
Publication of CN115572045A publication Critical patent/CN115572045A/en
Pending legal-status Critical Current

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    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B18/00—Shaping glass in contact with the surface of a liquid
    • C03B18/02—Forming sheets
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B25/00—Annealing glass products
    • C03B25/04—Annealing glass products in a continuous way
    • C03B25/06—Annealing glass products in a continuous way with horizontal displacement of the glass products
    • C03B25/08—Annealing glass products in a continuous way with horizontal displacement of the glass products of glass sheets
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B35/00—Transporting of glass products during their manufacture, e.g. hot glass lenses, prisms
    • C03B35/14—Transporting hot glass sheets or ribbons, e.g. by heat-resistant conveyor belts or bands
    • C03B35/16—Transporting hot glass sheets or ribbons, e.g. by heat-resistant conveyor belts or bands by roller conveyors
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C17/00—Surface treatment of glass, not in the form of fibres or filaments, by coating
    • C03C17/001—General methods for coating; Devices therefor
    • C03C17/002—General methods for coating; Devices therefor for flat glass, e.g. float glass
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C17/00—Surface treatment of glass, not in the form of fibres or filaments, by coating
    • C03C17/22—Surface treatment of glass, not in the form of fibres or filaments, by coating with other inorganic material
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C2217/00—Coatings on glass
    • C03C2217/20—Materials for coating a single layer on glass
    • C03C2217/28—Other inorganic materials
    • C03C2217/287—Chalcogenides
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C2218/00—Methods for coating glass
    • C03C2218/10—Deposition methods
    • C03C2218/15—Deposition methods from the vapour phase

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Re-Forming, After-Treatment, Cutting And Transporting Of Glass Products (AREA)

Abstract

The present invention relates to a float glass manufacturing apparatus and a float glass manufacturing method. The invention provides a technique for improving the quality of a glass ribbon. The float glass manufacturing device comprises: a float furnace for forming a glass ribbon on molten metal; a dross box having a plurality of lift rollers to pull up the glass ribbon; and a lehr having a plurality of annealing rollers that convey the glass ribbon. The slow cooling furnace comprises: a pair of side wall portions provided so as to sandwich the conveyance path of the glass ribbon; a ceiling portion covering an upper portion of the conveying path; a gas jetting nozzle jetting sulfur oxide gas from below the conveying path to the conveying path; and a gas suction nozzle inserted from the side wall portion to the inside and sucking a gas below to the upper side or sucking a gas on the side to the side above the conveyance path. The gas suction nozzle is disposed at the same position as the gas discharge nozzle or at a position upstream of the gas discharge nozzle in the transport direction.

Description

Float glass manufacturing device and float glass manufacturing method
Technical Field
The present disclosure relates to a float glass manufacturing apparatus and a float glass manufacturing method.
Background
A float glass manufacturing device comprises: a float furnace that forms a glass ribbon on a molten metal; a dross box having a plurality of lift rollers to pull up a glass ribbon; and a slow cooling furnace having a plurality of annealing rolls that carry the glass ribbon. The float glass is obtained by cutting the glass ribbon after being slowly cooled in the slow cooling furnace into a desired size and shape.
In order to suppress oxidation of the molten metal, the interior of the float kiln is filled with a reducing gas. The reducing gas flows into the inside of the dross box from the inside of the float kiln, and the inside of the dross box is also filled with the reducing gas. On the other hand, the interior of the slow cooling furnace is filled with air.
The dross box contains a carbon member in contact with the lift roller. The carbon member removes dross attached to the lift roller. Dross is an oxide obtained by oxidation of molten metal carried into the dross box together with the glass ribbon.
When air flows into the interior of the dross box from the interior of the slow cooling furnace, the carbon member is oxidized and consumed by oxygen in the air, and therefore, it is difficult to remove dross. As a result, damage occurs to the lower surface of the glass ribbon.
Patent document 1 discloses a technique for suppressing the inflow of air from the inside of a cooling furnace into the inside of a dross box by an atmosphere partition device. The atmosphere partition device partitions a space below a conveying path for conveying the glass ribbon in the dross box and a space below the conveying path in the slow cooling furnace.
Documents of the prior art
Patent document
Patent document 1: japanese patent laid-open publication No. 2016-050160
Disclosure of Invention
Problems to be solved by the invention
The slow cooling furnace has a gas ejection nozzle for ejecting the sulfur oxide gas from a lower part of the conveying path of the glass ribbon to the conveying path. The sulfur oxide gas reacts with the lower surface of the glass ribbon to form a buffer film on the lower surface of the glass ribbon. The buffer film mitigates collision of the glass ribbon with the annealing roller. The buffer film contains sulfate crystals and the like. The sulfate crystals are formed under an oxidizing atmosphere.
In the dross box, when the gap between the upper surface of the glass ribbon and the curtain is narrow, the reducing gas may flow into the inside of the annealing furnace from the inside of the dross box violently. The reducing gas flowing in is bypassed from above to below the glass ribbon. As a result, there are problems such as disturbance of the flow of the sulfur oxide gas and reduction in the oxygen concentration around the gas discharge nozzle. Therefore, formation of the buffer film is inhibited, and the lower surface of the glass ribbon is easily damaged.
One embodiment of the present disclosure provides a technique for suppressing the formation of a buffer film from being inhibited by a reducing gas flowing into a slow cooling furnace from the inside of a dross box, thereby improving the quality of a glass ribbon.
Means for solving the problems
A float glass manufacturing device according to one embodiment of the present disclosure includes: a float furnace that forms a glass ribbon on a molten metal; a dross box having a plurality of lift rollers to pull up the glass ribbon; and a slow cooling furnace having a plurality of annealing rollers that transport the glass ribbon. The slow cooling furnace comprises: a pair of side wall portions provided so as to sandwich the conveyance path of the glass ribbon; a ceiling portion covering an upper portion of the conveying path; a gas ejection nozzle that ejects a sulfur oxide gas from below the conveyance path to the conveyance path; and a gas suction nozzle inserted from the side wall portion to the inside and sucking a gas below to the upper side or sucking a gas on the side to the side above the conveyance path. The gas suction nozzle is disposed at the same position as the gas discharge nozzle or at a position upstream of the gas discharge nozzle in the transport direction.
Effects of the invention
According to one aspect of the present disclosure, the reducing gas flowing into the interior of the slow cooling furnace from the interior of the dross box can be restricted from reaching the periphery of the gas discharge nozzle by the gas suction nozzle, and the formation of the buffer film can be suppressed from being hindered, thereby improving the quality of the glass ribbon.
Drawings
Fig. 1 is a side sectional view showing a float glass manufacturing apparatus according to an embodiment.
Fig. 2 is a front cross-sectional view showing an example of the slow cooling furnace.
Description of the reference symbols
1. Float glass manufacturing device
2. Floating-throwing kiln
3. Scum box
5. Slow cooling furnace
51. Annealing roller
521. 522 side wall part
523. Ceiling part
53. First gas ejection nozzle (gas ejection nozzle)
56. Gas suction nozzle
M molten metal
G glass ribbon
Detailed Description
Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the drawings, the same or corresponding components are denoted by the same reference numerals, and description thereof may be omitted. In each drawing, the X-axis direction, the Y-axis direction, and the Z-axis direction are perpendicular to each other, the X-axis direction and the Y-axis direction are horizontal, and the Z-axis direction is vertical. The X-axis direction is the conveyance direction of the glass ribbon G, and the Y-axis direction is the width direction of the glass ribbon G. In the present specification, "to" indicating a numerical range means to include numerical values described before and after the range as a lower limit value and an upper limit value.
A float glass manufacturing apparatus 1 according to an embodiment will be described with reference to fig. 1. The float glass manufacturing apparatus 1 includes a float furnace 2, a dross box 3, and a slow cooling furnace 5 from the upstream side in the conveyance direction of the glass ribbon G to the downstream side in the conveyance direction of the glass ribbon G. The float glass manufacturing apparatus 1 forms a glass ribbon G on a molten metal M stored in a float furnace 2, and feeds the formed glass ribbon G to a slow cooling furnace 5 by pulling it out of the float furnace 2 by a plurality of lift rollers 31 provided inside a dross box 3. In addition, the float glass manufacturing apparatus 1 gradually cools the glass ribbon G inside the slow cooling furnace 5, and then cuts it into a desired size and shape. The float glass is obtained by cutting the glass ribbon G.
The float glass is, for example, alkali-free glass, aluminosilicate glass, borosilicate glass, soda-lime glass, or the like. The alkali-free glass means that Na is not substantially contained 2 O、K 2 And alkali metal oxide glasses such as O. Here, the substantial absence of the alkali metal oxide means that the total content of the alkali metal oxide is 0.1 mass% or less.
The use of the float glass is not particularly limited, and is, for example, a cover glass for a display (e.g., a liquid crystal display, an organic Electroluminescence (EL) display, or the like). When the float glass is used as a cover glass, the float glass is a glass for chemical strengthening. The glass for chemical strengthening contains an alkali metal oxide, unlike alkali-free glass.
For example, the chemical strengthening glass contains 62 to 68% of SiO in mol% based on the oxide 2 6 to 12 percent of Al 2 O 3 7 to 13 percent of MgO and 9 to 17 percent of Na 2 O, 0 to 7 percent of K 2 O，Na 2 O and K 2 The total content of O minus Al 2 O 3 Content of less than 10%, and containing ZrO 2 In the case of (2), zrO 2 The content of (B) is 0.8% or less.
The other glass for chemical strengthening contains 65 to 85% of SiO in mol% based on the oxide 2 3 to 15 percent of Al 2 O 3 5 to 15 percent of Na 2 O, 0 to less than 2 percent of K 2 O, 0 to 15 percent of MgO and 0 to 1 percent of ZrO 2 And SiO 2 And Al 2 O 3 SiO in total content 2 +Al 2 O 3 Is 88% or less.
Another glass for chemical strengthening contains 50 to 75% of SiO in terms of mol% based on oxides 2 9 to 20 percent of Al 2 O 3 10 to 20 percent of Na 2 O, 0 to 6 percent of K 2 O, 0 to 15% of MgO, 0 to 10% of CaO, srO and BaO in terms of the total amount (CaO + SrO + BaO), and the total amount (ZrO) 2 +TiO 2 ) Calculated by 0 to 5 percent of ZrO 2 And TiO 2 2 0 to 10 percent of B 2 O 3 0 to 20 percent of Li 2 O。
The float glass may be used as a glass substrate for forming a thin film transistor, a color filter, or the like of a display. When the application of the float glass is a glass substrate, the float glass is alkali-free glass. The alkali-free glass is substantially free of alkali metal oxides, unlike the glass for chemical strengthening.
For example, the alkali-free glass contains 50 to 73% of SiO in terms of mass% based on oxides 2 10.5 to 24 percent of Al 2 O 3 0 to 12 percent of B 2 O 3 0 to 10 percent of MgO, 0 to 14.5 percent of CaO, 0 to 24 percent of SrO, 0 to 13.5 percent of BaO, 8 to 29.5 percent of MgO + CaO + SrO + BaO and 0 to 5 percent of ZrO 2 。
In the case where both high strain point and high melting property are satisfied, it is preferable that the alkali-free glass contains 58% to 66% of SiO by mass% based on oxides 2 15 to 22 percent of Al 2 O 3 5 to 12 percent of B 2 O 3 0 to 8 percent of MgO, 0 to 9 percent of CaO, 3 to 12.5 percent of SrO, 0 to 2 percent of BaO and 9 to 18 percent of MgO + CaO + SrO + BaO.
When it is desired to obtain a particularly high strain point, the alkali-free glass preferably contains 54 to 73% by mass of SiO based on the oxide 2 10.5 to 22.5 percent of Al 2 O 3 0 to 5.5 percent of B 2 O 3 0 to 10 percent of MgO, 0 to 9 percent of CaO, 0 to 16 percent of SrO, 0 to 2.5 percent of BaO and 8 to 26 percent of MgO + CaO + SrO + BaO.
The thickness of the float glass is selected according to the use of the float glass. When the float glass is used as a cover glass for a display, the thickness of the float glass is, for example, 0.1mm to 2.0mm. On the other hand, in the case where the application of the float glass is a glass substrate for a display, the thickness of the float glass is, for example, 0.1mm to 0.7mm.
Next, the floating kiln 2 and the like according to one embodiment will be described with reference to fig. 1 again. The float kiln 2 has a bath 21. The bath 21 contains molten metal M. As the molten metal M, for example, molten tin is used. In addition to the molten tin, a molten tin alloy or the like may be used, and the molten metal M may have a higher density than the molten glass. The molten glass is continuously supplied onto the molten metal M, and is formed into a glass ribbon G having a band plate shape by a smooth liquid surface of the molten metal M.
The float kiln 2 has a ceiling 22 forming a space above the bath 21. In order to prevent oxidation of the molten metal M, the interior of the float kiln 2 is filled with a reducing gas and is maintained at a pressure higher than atmospheric pressure. The reducing gas is, for example, a mixed gas of nitrogen and hydrogen, and the reducing gas contains 85 to 98.5 vol% of nitrogen and 1.5 to 15 vol% of hydrogen. The reducing gas is supplied from the joints between the tiles of the ceiling 22 and the holes of the ceiling 22.
The float furnace 2 has a heater 23 for heating the glass ribbon G. The heater 23 is suspended from, for example, the ceiling 22, and heats the glass ribbon G passing therebelow. The heater 23 is, for example, an electric heater, and is heated by energization. The heaters 23 are arranged in a matrix in the conveyance direction and the width direction of the glass ribbon G. By controlling the outputs of the plurality of heaters 23, the temperature distribution of the glass ribbon G can be controlled, and the sheet thickness distribution of the glass ribbon G can be controlled.
The dross box 3 has a lift roller 31 for pulling up the glass ribbon G. The lift roller 31 is rotationally driven by a driving device (not shown) such as a motor, and conveys the glass ribbon G obliquely upward by its driving force. The driving device is arranged outside the scum box 3. Therefore, a hole into which the lift roller 31 is inserted is formed in the outer wall of the dross box 3.
Inside the dross box 3, a plurality of lift rollers 31 are arranged at intervals along the conveyance direction (X-axis direction) of the glass ribbon G. In fig. 1, the number of the lift rollers 31 is 3, but a plurality of the lift rollers may be 2, or 4 or more. The axial direction of the lift roller 31 is the same direction as the width direction (Y-axis direction) of the glass ribbon G.
The dross box 3 has a carbon member 32 in contact with the lift roller 31. The carbon member 32 is disposed in the lower space of the dross box 3. The lower space of the dross box 3 is a space below the glass ribbon G. The carbon member 32 is in contact with the outer circumferential surface of the lift roller 31, thereby removing foreign substances attached to the outer circumferential surface of the lift roller 31. The foreign matter includes, for example, oxides obtained by oxidizing the molten metal M taken into the dross box 3 together with the glass ribbon G, so-called dross.
The carbon member 32 is, for example, a rectangular parallelepiped. The carbon member 32 may be a quadrangular prism having a trapezoidal or inverted trapezoidal shape when viewed from the X-axis direction. A plurality of carbon members 32 may be provided in the axial direction of the lift roller 31. The number of carbon members 32 arranged along each lift roller 31 is determined according to the width (Y-axis direction dimension) of the glass ribbon G or the axial length (Y-axis direction dimension) of the lift roller 31.
The carbon member 32 has a dimension in the Y-axis direction of, for example, 300mm to 1000mm, preferably 400mm to 800mm. The dimension of the carbon member 32 in the Z-axis direction is, for example, 50mm to 200mm, preferably 70mm to 150mm. The carbon member 32 has a dimension in the X-axis direction of, for example, 20mm to 100mm, preferably 30mm to 80mm.
The carbon member 32 may comprise graphite powder. The maximum particle diameter of the graphite powder is, for example, 0.1mm to 3mm, preferably 0.5mm to 2.5mm. When the maximum particle diameter of the graphite powder is 0.1mm to 3mm, the strength of the carbon member 32 as a molded body of the graphite powder can be ensured.
The shore hardness of the carbon member 32 is, for example, 20HS to 90HS, preferably 30HS to 80HS. When the shore hardness of the carbon member 32 is 20HS to 90HS, the abrasion resistance of the carbon member 32 to the lift roller 31 can be ensured.
The dross box 3 may have an urging member 33 which presses the carbon member 32 onto the lift roller 31. The biasing member 33 includes a metal spring, for example. The spring is a plate spring. Instead of the plate spring, the urging member 33 may include a coil spring, a compression coil spring, a disc spring, a spiral spring, a ring spring, or the like. The urging member 33 may include a fluid pressure cylinder such as a pneumatic cylinder.
The dross box 3 may have a support member 34 that supports the carbon member 32 freely up and down. The support member 34 is disposed on the bottom wall 35 of the dross box 3. The support member 34 has a U-shaped cross section perpendicular to the Y-axis direction, and the carbon member 32 and the urging member 33 are disposed inside the support member 34. The support member 34 prevents the carbon member 32 and the urging member 33 from being displaced in the X-axis direction.
In order to adjust the temperature of the glass ribbon G, the dross box 3 may have a heater 37 on the ceiling 36. The heater 37 may be provided not only above the glass ribbon G but also below the glass ribbon G. In the dross box 3, the temperature of the glass ribbon G is preferably (Tg-50 ℃) to (Tg +30 ℃) based on the glass transition temperature Tg of the float glass.
The dross box 3 includes a cover 38 above the glass ribbon G, a heat insulating material 39 disposed on the cover 38, and a curtain 40 extending through a part of the heat insulating material 39 and the cover 38 and suspended from the lower surface of the cover 38. The curtain 40 is a plate-like member made of a refractory material such as a steel material or a glass material.
The curtain 40 partitions the upper space of the dross box 3 into a plurality of spaces in the conveyance direction (X-axis direction) of the glass ribbon G. The upper space of the dross box 3 is a space above the glass ribbon G. The curtain 40 is disposed, for example, directly above the rotation center line of each lift roller 31. The curtain 40 extends in the axial direction (Y-axis direction) of each lift roller 31.
The slow cooling furnace 5 slowly cools the glass ribbon G to a temperature equal to or lower than the strain point of the glass while conveying the glass ribbon G by the annealing rollers 51. The annealing furnace 5 has heaters (not shown) on the ceiling and the bottom wall to adjust the temperature of the glass ribbon G. The annealing roller 51 is rotationally driven by a driving device (not shown) such as a motor, and conveys the glass ribbon G in the horizontal direction by its driving force. The outlet of the slow cooling furnace 5 on the downstream side is open to the outside. Therefore, the air flows into the interior of the slow cooling furnace 5.
Next, an example of the slow cooling furnace 5 will be described with reference to fig. 1 and 2. As shown in fig. 1, the slow cooling furnace 5 includes, for example, a furnace body 52, a first gas ejection nozzle 53, a second gas ejection nozzle 54, a gas concentration meter 55, and a gas suction nozzle 56. Further, as shown in fig. 2, the slow cooling furnace 5 may have an injector 57 and a vertical pipe 58.
As shown in fig. 2, the furnace body 52 has a rectangular shape when viewed from the X-axis direction, for example. The furnace body 52 includes a pair of side walls 521 and 522, a ceiling portion 523, and a bottom wall 524. The pair of side wall portions 521 and 522 are provided so as to sandwich the conveyance path of the glass ribbon G in the Y-axis direction. The ceiling portion 523 covers the upper side of the conveyance path of the glass ribbon G. The bottom wall 524 covers the lower portion of the conveyance path of the glass ribbon G. The pair of side walls 521 and 522 are vertically provided so as to be orthogonal to the Y-axis direction, and the ceiling portion 523 and the bottom wall portion 524 are horizontally provided.
As shown in fig. 1, the first gas ejection nozzle 53 ejects the sulfur oxide gas from below the conveyance path of the glass ribbon G toward the conveyance path. The first gas ejection nozzle 53 extends, for example, in the Y-axis direction, and has a plurality of gas ejection ports at intervals in the Y-axis direction. Each gas ejection port ejects the sulfur oxide gas upward.
The sulfur oxide gas reacts with the lower surface of the glass ribbon G to form a buffer film on the lower surface of the glass ribbon G. The buffer film mitigates the collision of the glass ribbon G with the annealing roller 51, and suppresses the occurrence of damage on the lower surface of the glass ribbon G. The buffer film contains sulfate crystals and the like. The sulfate crystals are formed under an oxidizing atmosphere.
The first gas ejection nozzle 53 ejects, for example, SO 2 The gas acts as a sulfur oxide gas, thereby forming sulfate crystals.
The first gas ejection nozzle 53 is disposed, for example, between the first annealing roller 51 and the second annealing roller 51 in the direction from the upstream side in the conveyance direction of the glass ribbon G to the downstream side in the conveyance direction of the glass ribbon G. The first (most upstream) annealing roll 51 can block the flow of the reducing gas flowing from the inside of the dross box 3 into the inside of the slow cooling furnace 5 from flowing toward the sulfur oxide gas ejection port. Therefore, the flow of the sulfur oxide gas can be suppressed from being disturbed. Further, a buffer film can be formed on the relatively upstream side of the annealing furnace 5, and the lower surface of the glass ribbon G can be prevented from being damaged.
Although not shown, the first gas ejection nozzle 53 may be disposed upstream of the first (most upstream) annealing roll 51. Although not shown, the first gas ejection nozzle 53 may be disposed downstream of the second annealing roller 51 in the conveyance direction.
The second gas ejection nozzle 54 ejects a gas containing oxygen from below the conveyance path of the glass ribbon G toward the conveyance path. The second gas ejection nozzle 54 extends, for example, in the Y-axis direction, and has a plurality of gas ejection ports at intervals in the Y-axis direction. Each gas ejection port ejects a gas containing oxygen upward.
The oxygen-containing gas may be pure oxygen or air as long as it is an oxygen-containing gas. The oxygen concentration in the vicinity of the first gas ejection nozzle 53 can be increased to promote the generation of sulfate.
The second gas ejection nozzle 54 is preferably disposed in the vicinity of the first gas ejection nozzle 53, and may be disposed between the first annealing roller 51 and the second annealing roller 51 in the direction from the upstream side in the conveyance direction of the glass ribbon G to the downstream side in the conveyance direction of the glass ribbon G, for example. The oxygen concentration in the periphery of the first gas ejection nozzle 53 can be effectively increased.
The second gas ejection nozzle 54 may be provided in the vicinity of the first gas ejection nozzle 53, and the second gas ejection nozzle 54 may be disposed on the upstream side of the first (most upstream) annealing roller 51 or on the downstream side of the second annealing roller 51 in the conveyance direction, as in the case of the first gas ejection nozzle 53.
Gas concentration meter 55 for measuring O 2 Gas concentration, SO 2 Gas concentration or H 2 O gas concentration, etc. The gas concentration meter 55 is provided in the vicinity of the first gas ejection nozzle 53, for example, below the first gas ejection nozzle 53. A desired gas concentration can be detected in the vicinity of the first gas ejection nozzle 53 by the gas concentration meter 55, and the gas flow rate can be adjusted so that the gas concentration is within an allowable range. Although not shown, the gas concentration meter 5A pressure gauge may be provided in the vicinity of 5. The pressure gauge measures the pressure in the vicinity of the first gas ejection nozzle 53.
Incidentally, when the gap between the upper surface of the glass ribbon G and the curtain 40 is narrow in the dross box 3, the reducing gas may flow into the inside of the annealing furnace 4 from the inside of the dross box 3 violently. The reducing gas flows along the upper surface of the glass ribbon G.
Conventionally, the reducing gas flowed in is circulated from above the glass ribbon G to below the glass ribbon G and reaches the periphery of the first gas discharge nozzle 53. As a result, there are problems such as disturbance of the flow of the sulfur oxide gas and reduction in the oxygen concentration around the gas discharge nozzle. Therefore, the formation of the buffer film is inhibited, and the lower surface of the glass ribbon is easily damaged.
The gas suction nozzle 56 is inserted from the side wall portions 521, 522 to the inside, and sucks the gas above the conveyance path of the glass ribbon G. The air suction nozzle 56 sucks the air from the lower side to the upper side in the present embodiment, and may suck the air from the side to the side. It should be noted that the air suction nozzle 56 may be provided only on any one of the pair of side wall portions 521, 522.
The gas suction nozzle 56 is disposed upstream of the first gas discharge nozzle 53 in the conveyance direction of the glass ribbon G. The gas suction nozzle 56 may be disposed at the same position as the first gas ejection nozzle 53 in the conveyance direction of the glass ribbon G.
According to the present embodiment, the gas suction nozzle 56 is disposed upstream of the first gas discharge nozzle 53 in the conveyance direction of the glass ribbon G, or at the same position as the first gas discharge nozzle 53, and sucks the reducing gas flowing along the upper surface of the glass ribbon G upward. Therefore, the reducing gas can be restricted from reaching the periphery of the first gas ejection nozzle 53, and the formation of the buffer film can be suppressed from being hindered, so that the quality of the glass ribbon can be improved.
As a technique different from the technique of the present disclosure, it is conceivable to provide an opening in the ceiling portion 523 of the furnace body 52 and discharge the reducing gas to the outside of the furnace body 52 through the opening. However, when the opening is provided in the ceiling portion 523, the heat insulation property of the ceiling portion 523 is lowered. As a result, the glass ribbon G is rapidly cooled below the opening portion, and a large residual stress is generated in the glass ribbon G.
According to the present embodiment, the ceiling portion 523 is not provided with an opening portion, and the air suction nozzle 56 is inserted through the small opening portions of the side wall portions 521 and 522. Therefore, a decrease in the heat insulating property of the furnace body 52 can be suppressed, a rapid decrease in the temperature of the glass ribbon G can be suppressed, and the residual stress generated in the glass ribbon G can be reduced.
The gas suction nozzles 56 may be disposed directly above a region where the temperature of the glass ribbon G is equal to or higher than the strain point. The reducing gas flowing in from the dross box 3 can be sucked on the relatively upstream side of the slow cooling furnace 5 by the gas suction nozzle 56. Therefore, the reducing gas can be discharged to the outside of the furnace body 52 before the reducing gas is diffused.
The gas suction nozzle 56 is disposed, for example, upstream of the first annealing roll 51 in the direction from the upstream side in the conveyance direction of the glass ribbon G to the downstream side in the conveyance direction of the glass ribbon G. The reducing gas flowing from the dross box 3 can be sucked in the uppermost stream of the slow cooling furnace 5 by the gas suction nozzle 56. Therefore, the reducing gas can be discharged to the outside of the furnace body 52 before the reducing gas is diffused.
The gas suction nozzles 56 extend from the pair of side wall portions 521, 522 to above the conveyance path of the glass ribbon G in the Y-axis direction, respectively, and suck the gas below to above. The air suction nozzle 56 sucks air from below to directly above or obliquely above. The gas suction nozzle 56 includes a suction port 56a through which gas is sucked.
For example, the suction port 56a of one of the gas suction nozzles 56 may overlap at least one widthwise end Ga of the glass ribbon G as viewed from above, and extend outward in the width direction of the glass ribbon G from the one widthwise end Ga of the glass ribbon G. Further, the suction port 56a of the other gas suction nozzle 56 may overlap at least the other end Gb in the width direction of the glass ribbon G and extend outward in the width direction of the glass ribbon G from the other end Gb in the width direction of the glass ribbon G as viewed from above.
The reducing gas in the dross box 3 flows into the interior of the slow cooling furnace 5 through the gap between the lift roller 31 and the curtain 40. At this time, since the glass ribbon G is not present on the outer side in the width direction of the glass ribbon G, the gap size is large, and the flow of the reducing gas is easily formed.
If the suction port 56a of one gas suction nozzle 56 extends outward in the width direction of the glass ribbon G from one end Ga in the width direction of the glass ribbon G when viewed from above, the reducing gas flowing outward in the width direction of the glass ribbon G can be efficiently sucked. Similarly, if the suction port 56a of the other gas suction nozzle 56 extends outward in the width direction of the glass ribbon G from the other end Gb in the width direction of the glass ribbon G when viewed from above, the reducing gas flowing outward in the width direction of the glass ribbon G can be efficiently sucked.
When viewed from above, the suction port 56a of one of the gas suction nozzles 56 may extend from one end in the width direction of the glass ribbon G to the center in the width direction of the glass ribbon G, and the suction port 56a of the other gas suction nozzle 56 may extend from the other end in the width direction of the glass ribbon G to the center in the width direction of the glass ribbon G. The reducing gas can be sucked out over the entire width direction of the glass ribbon G.
The air suction nozzle 56 sucks the air from below to above in the present embodiment, but may suck the air from the side to the side. In this case, for example, the suction ports 56a of the one gas suction nozzle 56 may be arranged to face each other toward one end in the width direction of the glass ribbon G when viewed from above, and may suck out the reducing gas flowing outside in the width direction of the glass ribbon G. Both the air suction nozzle 56 that sucks the lower air upward and the air suction nozzle 56 that sucks the side air downward may be used.
The ejector 57 adjusts the suction amount of the gas suction nozzle 56. By adjusting the suction amount of the gas suction nozzle 56, it is possible to control various gas concentrations within an allowable range at the periphery of the first gas ejection nozzle 53. The suction amount of the air suction nozzle 56 can also be controlled based on the measurement result of the air concentration meter 55.
The straight pipe 58 extends upward from one end of the air suction nozzle 56 outside the pair of side wall portions 521 and 522. The air drawn by the air suction nozzle 56 is cooled as it rises in the vertical tube 58. The temperature of the gas decreases from the lower side of the vertical pipe 58 to the upper side of the vertical pipe 58. The rising airflow can be formed inside the vertical pipe 58 by the temperature difference of the gas, and the gas can be efficiently sucked into the gas suction nozzle 56. In addition, it is easier to secure a space for an operator to operate near the furnace body 52 than in the case where the vertical pipe 58 extends in the X-axis direction from one end of the gas suction nozzle 56.
The injector 57 is provided at a lower end of the vertical pipe 58, and includes an injector nozzle 57a that ejects gas such as compressed air upward. The rising speed of the rising airflow formed inside the vertical pipe 58 by the gas ejected from the ejector nozzle 57a can be increased, and the gas can be sucked into the gas suction nozzle 56 more efficiently.
Examples
The experimental data will be described below. The following example 1 is a comparative example, and examples 2 to 4 are examples. In examples 1 to 4, float glass was produced under the conditions shown in table 1 using the float glass production apparatus 1 shown in fig. 1 and 2. In examples 1 to 4, except for the amount of suction of gas (unit: nm) by the gas suction nozzle 56 3 Hour), float glass was produced under the same conditions. For example, the ejection rate (unit: NL/min) of the first gas ejection nozzles 53 is set to be the same in examples 1 to 4, and the ejection rate (unit: NL/min) of the second gas ejection nozzles 54 is set to be the same in examples 1 to 4.
TABLE 1
Example 1 Example 2 Example 3 Example 4
Suction volume [ arbitrary unit ]] 0 0.23 0.63 1
O 2 Concentration [ arbitrary unit ]] 1 1.31 1.79 2
SO 2 Concentration [ arbitrary unit ]] 1 2.27 4.33 4.67
H 2 O concentration [ arbitrary unit ]] 1 0.50 0.55 0.41
Pressure [ arbitrary unit ]] 1 1.02 1.02 0.86
In Table 1, the suction amount, O, of the air suction nozzle 56 is expressed as a relative value 2 Gas concentration, SO 2 Gas concentration, H 2 O gas concentration and pressure. Note that, O is measured by the gas concentration meter 55 2 Gas concentration (% by volume), SO 2 Gas concentration (unit: volume ppm), H 2 O gas concentration (unit: g/cm) 3 ) The measurement was carried out. The pressure (unit: pa) is a pressure difference from the atmospheric pressure, and is measured by a pressure gauge near the gas concentration meter 55.
As shown in table 1, in example 1, the gas was not sucked by the gas suction nozzle 56, whereas in examples 2 to 4, the gas was sucked by the gas suction nozzle 56. As a result, in examples 2 to 4, O was formed around the first gas discharge nozzle 53 in comparison with example 1 2 Gas concentration and SO 2 Higher concentration of gas, H 2 The O gas concentration is low.
When the reducing gas flows into the slow cooling furnace 5 from the inside of the dross box 3, H contained in the reducing gas 2 When the gas reaches the periphery of the first gas ejection nozzle 53, H 2 Gas and O 2 The gas reacts to produce H 2 And (4) O gas. As a result, at the periphery of the first gas ejection nozzle 53, H 2 O gas concentration is increased, and O 2 The gas concentration decreases.
As is clear from the results in table 1, if the gas is sucked by the gas suction nozzle 56, the reducing gas flowing into the inside of the slow cooling furnace 5 from the inside of the dross box 3 can be restricted from reaching the periphery of the first gas discharge nozzles 53.
Further, as is clear from the results in table 1, the larger the suction amount of the gas suction nozzle 56, the higher the O can be 2 Gas concentration and SO 2 Gas concentration and the more H can be reduced 2 The concentration of O gas. In example 4, the reason why the pressure is low is that the suction amount of the air suction nozzle 56 is large.
The float glass production apparatus and the float glass production method according to the present disclosure have been described above, but the present disclosure is not limited to the above embodiments and the like. Various changes, modifications, substitutions, additions, deletions, and combinations may be made within the scope of the claims. These are of course also within the technical scope of the present disclosure.

Claims (9)

1. A float glass manufacturing apparatus comprising:
a float bath that forms a glass ribbon on molten metal;
a dross box having a plurality of lift rollers to pull up the glass ribbon; and
a slow cooling furnace having a plurality of annealing rolls that carry the glass ribbon, wherein,
the slow cooling furnace is provided with: a pair of side wall portions provided so as to sandwich the conveyance path of the glass ribbon; a ceiling portion covering an upper portion of the conveying path; a gas ejection nozzle that ejects a sulfur oxide gas from below the conveyance path to the conveyance path; and a gas suction nozzle inserted from the side wall portion to the inside and sucking a gas below to the upper side or sucking a gas on the side to the side above the conveying path, wherein the suction nozzle is provided with a suction hole for sucking a gas on the side
The gas suction nozzle is disposed at the same position as the gas discharge nozzle or at a position upstream of the gas discharge nozzle in the conveyance direction of the glass ribbon.
2. The float glass manufacturing apparatus of claim 1, wherein the gas suction nozzle is disposed directly above a region of the glass ribbon at a temperature above a strain point.
3. The float glass manufacturing apparatus according to claim 1 or 2, wherein the slow cooling furnace has an ejector that adjusts a suction amount of the gas suction nozzle.
4. The float glass manufacturing apparatus according to any one of claims 1 to 3, wherein the slow cooling furnace has a vertical pipe extending upward from one end of the gas suction nozzle outside the pair of side wall portions.
5. The float glass manufacturing apparatus according to claim 1 or 2, wherein the annealing furnace has a straight pipe extending upward from one end of the gas suction nozzle on the outer side of the pair of side wall portions, and an ejector for adjusting the suction amount of the gas suction nozzle, and wherein the annealing furnace has a straight pipe extending upward from one end of the gas suction nozzle, and wherein
The ejector is provided at a lower end of the straight pipe and includes an ejector nozzle that ejects gas upward.
6. The float glass manufacturing apparatus according to any one of claims 1 to 5, wherein the gas ejection nozzle is disposed between a first one of the annealing rollers and a second one of the annealing rollers in a direction from an upstream side in the conveyance direction to a downstream side in the conveyance direction.
7. The float glass manufacturing apparatus according to any one of claims 1 to 6, wherein the gas suction nozzle is disposed at a position further upstream than a first one of the annealing rollers in a direction from an upstream side in the conveyance direction to a downstream side in the conveyance direction.
8. The float glass manufacturing apparatus of any one of claims 1 to 7, wherein the gas suction nozzle comprises a suction port through which gas is sucked, and wherein
The suction port of the gas suction nozzle overlaps one widthwise end of the glass ribbon when viewed from above, and extends outward in the width direction from the one widthwise end of the glass ribbon.
9. A float glass production method for producing float glass using the float glass production apparatus according to any one of claims 1 to 8.
CN202210665970.8A 2021-06-21 2022-06-14 Float glass manufacturing device and float glass manufacturing method Pending CN115572045A (en)

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JP2021102233A JP2023001476A (en) 2021-06-21 2021-06-21 Float glass production device, and float glass production method

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