JP2021109816A - Float glass manufacturing device and float glass manufacturing method - Google Patents

Abstract

To provide a float glass manufacturing device that forms a uniform clearance between a lower end of a sheet part and a glass ribbon in a width direction of the glass ribbon even when a frame part constituting a drape and the sheet part are formed of different materials, and can prevent the sheet part from deforming, and to provide a float glass manufacturing method.SOLUTION: A float glass manufacturing device includes a float bath 10, a slow cooling furnace 20 and a dross box 30. The dross box 30 includes a drape 6 in an upper part of multiple lift-out rolls 4 for transporting a glass ribbon G. The drape 6 includes: a sheet part 62; a frame part 61 for nipping an upper part of the sheet part 62; and a bolt 63 for fastening the sheet part 62 and the frame part 61. The sheet part 62 and the frame part 61 are formed of different materials. The sheet part includes a first through-hole 65 through which the bolt 63 is inserted. The first through-hole 65 is a long hole of which long side is a longitudinal direction of the drape 6.SELECTED DRAWING: Figure 1

Description

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

The float glass manufacturing apparatus includes a float bath for accommodating the molten metal, a slow cooling furnace for carrying a glass ribbon formed in a strip shape on the molten metal, and a dross box provided between the float bath and the slow cooling furnace. ..

Inside the dross box, drapes are placed on top of a plurality of lift-out rolls that carry the glass ribbon. The drape functions to prevent the pressure in the dross box and the float bath from fluctuating and oxygen in the slow cooling furnace from entering the dross box and the float bath.

The drape is in a state where the surface on the upstream side in the transport direction of the glass ribbon is constantly under the atmospheric pressure from the float bath. Therefore, with the passage of time, the surface of the drape on the downstream side in the transport direction of the glass ribbon swells and deforms, and the drape may not sufficiently perform the above-mentioned function.

Therefore, in order to prevent the drape from being deformed, a drape having a frame portion and a corrugated iron plate portion and a reinforcing means provided on the downstream side in the transport direction of the glass ribbon has been proposed (see Patent Document 1). ..

JP-A-2016-204248

However, the technique of Patent Document 1 may not be able to sufficiently prevent the deformation of the drape (corrugated iron plate portion).

Therefore, when we examined changing the material of the corrugated iron plate part (corresponding to the sheet part of the present invention), this time, due to the difference in the coefficient of thermal expansion of the material between the frame part and the sheet part, the sheet part was moved in the width direction of the glass ribbon. It does not expand uniformly, and the gap between the lower end of the sheet and the glass ribbon becomes non-uniform in the width direction of the glass ribbon. Then, the pressure in the dross box and the float bath fluctuates, causing defects on the surface of the glass ribbon.

The present invention has been made in view of the above problems, and even if the materials of the frame portion and the sheet portion constituting the drape are different, the gap between the lower end of the sheet portion and the glass ribbon is in the width direction of the glass ribbon. It is an object of the present invention to provide a float glass manufacturing apparatus and a float glass manufacturing method which are uniform and can prevent deformation of a sheet portion.

In order to solve the above problems, the float glass manufacturing apparatus of the present invention includes a float bath for accommodating molten metal, a slow cooling furnace in which a glass ribbon formed in a strip shape on the molten metal is carried in, and the float bath. A float glass manufacturing apparatus provided with a dross box provided between the slow cooling furnace, wherein the dross box has a drape on the upper part of a plurality of lift-out rolls for carrying the glass ribbon, and the drape is a drape. It has a seat portion, a frame portion that sandwiches the upper portion of the seat portion, and a bolt that fastens the seat portion and the frame portion. The material of the seat portion is different from that of the frame portion, and the bolt is inserted through the seat portion. It has a first through hole to be formed, and the first through hole is a long hole having a long side in the longitudinal direction of the drape.

Further, in the float glass manufacturing method of the present invention, a strip-shaped glass ribbon is formed on the molten metal of the float bath, the glass ribbon is pulled out from the float bath by a lift-out roll provided in a dross box, and a slow cooling furnace is used. A method for producing float glass in which the glass ribbon is slowly cooled, the dross box has a drape on the upper part of a plurality of lift-out rolls for carrying the glass ribbon, and the drape has a sheet portion and the sheet portion. The seat portion has a frame portion that sandwiches the upper portion of the glass portion, and a bolt that fastens the seat portion and the frame portion. The seat portion is made of a material different from that of the frame portion, and a first through hole through which the bolt is inserted is inserted. The first through hole is a long hole having a long side in the longitudinal direction of the drape.

According to the float glass manufacturing apparatus and the float glass manufacturing method of the present invention, even if the materials of the frame portion and the sheet portion constituting the drape are different, the gap between the lower end of the sheet portion and the glass ribbon is in the width direction of the glass ribbon. It is uniform and can prevent deformation of the seat portion.

It is a partial cross-sectional view of the float glass manufacturing apparatus which concerns on one Embodiment of this invention. It is a schematic block diagram of the drape of FIG. 1, (A) is a cross-sectional view taken along the line I-I of (B) and (C), (B) is a front view of the drape, and (C) is (A). ) Is a cross-sectional view taken along the line II-II. It is a schematic block diagram of the drape of FIG. 1, (A) is a cross-sectional view taken along the line III-III of (B) and (C), (B) is a front view of the drape, and (C) is (A). ) Is a cross-sectional view taken along the line II-II. 2 (C) and 3 (C) are overall views of the seat portion. It is a figure which shows the modification 1 of the drape of FIG. 2 (A). It is a figure which shows the modification 2 of the drape of FIG. 2 (A). 2 (A) is a diagram showing a modified example 3 of the drape, (A) is a state before the start of manufacturing the float glass, and (B) is a diagram showing the state when the float glass is being manufactured. be.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. In each drawing, the same or corresponding configurations are designated by the same or corresponding reference numerals and the description thereof will be omitted. In the present specification, "~" representing a numerical range means a range including numerical values before and after the range. In the following description, the "upstream side" refers to the upstream side in the transport direction of the glass ribbon, and the "downstream side" refers to the downstream side in the transport direction of the glass ribbon.

(Float glass manufacturing equipment)
A float glass manufacturing apparatus according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a partial cross-sectional view of a float glass manufacturing apparatus according to an embodiment of the present invention.

The float glass manufacturing apparatus 1 is located between a float bath 10 accommodating a molten metal M, a slow cooling furnace 20 into which a glass ribbon G formed in a strip shape on the molten metal M is carried, and the float bath 10 and the slow cooling furnace 20. It is provided with a dross box 30 provided in. The dross box 30 has a drape 6 on top of a plurality of lift-out rolls 4 that convey the glass ribbon G.

The glass ribbon G formed to a desired width and thickness is lifted from the bath surface 12 of the molten metal M by the traction force of the lift-out roll 4 and the transport roll 21. Then, the glass ribbon G is carried into the dross box 30 from the outlet 13 of the float bus 10, then carried into the slow cooling furnace 20 by the lift-out roll 4, and is slowly cooled while being carried by the transport roll 21. After that, the glass ribbon G is carried out of the slow cooling furnace 20, cooled to around room temperature, and then cut to a predetermined size to become a product glass plate.

The glass composition is appropriately selected according to the application of the glass plate and the like. For example, when the glass plate is used as a glass substrate for a liquid crystal display, alkali metal adversely affects the quality of the liquid crystal display. Therefore, alkali-free glass that does not substantially contain alkali metal oxides such as _{Na 2} O and K _{2 O.} Is used. Here, the fact that the alkali metal oxide is substantially not contained means that the total content of the alkali metal oxide is 0.1% by mass or less.

The upper space in the float bath 10 is filled with a reducing mixed gas containing nitrogen and hydrogen in order to prevent oxidation of the molten metal M. Further, the upper space in the float bath 10 is set higher than the atmospheric pressure in order to prevent the inflow of air from the outside. The reducing atmosphere in the float bath 10 flows out from the outlet 13 of the float bath 10 toward the dross box 30. A heater 18 for adjusting the glass ribbon G to a temperature at which it can be plastically deformed is provided near the outlet 13 of the float bath 10. The metal used for the molten metal M is, for example, tin or a tin alloy.

The outlet on the downstream side of the slow cooling furnace 20 is open to the outside. Therefore, the inside of the slow cooling furnace 20 has an atmosphere containing oxygen. The inside of the slow cooling furnace 20 communicates with the inside of the float bath 10 via the inside of the dross box 30.

In the slow cooling furnace 20, a heater 28 and the like are provided in addition to the transfer roll 21. Each of the plurality of transport rolls 21 is rotationally driven by a driving device such as a motor, and the glass ribbon G is transported in the horizontal direction by the driving force.

In the dross box 30, the upper outer wall 31 is covered with the heat insulating material 33, and the lower inner wall 32 is covered with the heat insulating material 34. By using the heat insulating materials 33 and 34, heat dissipation from the dross box 30 can be suppressed, the temperature distribution of the glass ribbon G can be stabilized, and warpage of the product can be suppressed.

In the dross box 30, in addition to the lift-out roll 4, a contact member 5, a drape 6, a heater 8, and the like are provided. Each of the plurality of lift-out rolls 4 is rotationally driven by a driving device such as a motor, and the driving force thereof conveys the glass ribbon G diagonally upward. The number of lift-out rolls is not particularly limited as long as there are a plurality of lift-out rolls.

The contact member 5 is provided below the lift-out roll 4. Each of the plurality of contact members 5 is in sliding contact with the outer peripheral surface of the corresponding lift-out roll 4, and partitions the lower part of the glass ribbon G into a plurality of spaces 35 to 38.

The drape 6 is provided above the glass ribbon G and above the lift-out roll 4 to shield the space above the glass ribbon G. A plurality of drapes 6 are suspended by the outer wall 31 and are provided at intervals in the transport direction of the glass ribbon G. The reducing atmosphere flowing out from the outlet 13 of the float bath 10 flows through the space above the glass ribbon G in the dross box 30 toward the inlet 23 of the slow cooling furnace 20 (exit 39 of the dross box 30).

The drape 6 limits the intrusion of oxygen from the slow cooling furnace 20 and regulates the increase in the oxygen concentration in the dross box 30. As a result, the combustion of hydrogen contained in the reducing atmosphere is suppressed, and the temperature fluctuation and local heating of the glass ribbon G due to the combustion flame of hydrogen can be suppressed. The drape 6 is arranged so as to be slightly (for example, 1 cm) away from the upper surface of the glass ribbon G so as not to interfere with the transportation of the glass ribbon G.

The plurality of heaters 8 are provided on both the upper and lower sides of the glass ribbon G at intervals, and a plurality of rows of heaters 8 are provided in the transport direction of the glass ribbon G, respectively. The heaters 8 in each row are provided between the drapes 6 and between the contact members 5. The heaters 8 in each row are preferably divided in the width direction of the glass ribbon G in order to make the temperature distribution in the width direction of the glass ribbon G uniform. The atmospheric temperature in the dross box 30 is adjusted to 550 ° C. or higher, although it depends on the glass composition.

The float glass manufacturing apparatus 1 preferably includes a surveillance camera in order to control the height of the drape 6, manage the gap between the drape 6 and the glass ribbon G, detect cracks in the glass ribbon G, and the like. The surveillance camera is provided on the outside of the side wall portion of the dross box 30, and photographs the drape 6 and the glass ribbon G in the dross box 30 from the window of the side wall portion. Then, the image taken by the surveillance camera is subjected to image processing. Thereby, the distance between the drape 6 and the glass ribbon G in the width direction of the glass ribbon G can be measured over time.

Then, by adjusting the height of the drape 6 to keep the distance between the drape 6 and the glass ribbon G constant, the flow rate of the reducing atmosphere flowing through the gap becomes constant, so that the quality of the glass ribbon G can be improved. It can be stabilized.

Further, since the drape 6 can prevent the deformation of the sheet portion as described later, the warp of the glass ribbon G can be quantitatively evaluated by measuring the distance between the drape 6 and the glass ribbon G. As a result, the heater 8 in the dross box 30 can be adjusted at an early stage, so that deterioration of the warp of the float glass can be suppressed.

(drape)
Next, the drapes constituting the float glass manufacturing apparatus will be described with reference to FIGS. 2 to 4.

FIG. 2 is a schematic configuration diagram of the drape of FIG. 1, (A) is a cross-sectional view taken along the line II of (B) and (C), (B) is a front view of the drape, and (C). ) Is a cross-sectional view taken along the line II-II of (A). FIG. 3 is a schematic configuration diagram of the drape of FIG. 1, (A) is a cross-sectional view taken along the line III-III of (B) and (C), (B) is a front view of the drape, and (C). ) Is a cross-sectional view taken along the line II-II of (A). Here, FIGS. 2 (B) and 3 (B) are front views when the drape is viewed from the upstream side to the downstream side.

As shown in FIG. 2A, the drape 6 has a seat portion 62, a frame portion 61 that sandwiches the upper portion of the seat portion 62, and a bolt 63 that fastens the seat portion 62 and the frame portion 61. The drape 6 further has a nut 64 for fixing the bolt 63.

The seat portion 62 is made of a different material from the frame portion 61 and has a first through hole 65 (see FIG. 2C) into which the bolt 63 is inserted. The first through hole 65 is an elongated hole having a long side in the longitudinal direction of the drape 6.

Since the frame portion 61 is suspended by the outer wall 31 (see FIG. 1) above the dross box, the frame portion 61 has frame members 61A and 61B having an inverted L-shaped cross section. The frame material 61A is arranged on the upstream side surface of the seat portion 62, and the frame material 61B is arranged on the downstream side surface of the seat portion 62.

The through holes of the frame materials 61A and 61B are round holes. The through hole of the frame material 61B may be a screw hole. In this case, the bolt 63 can be fixed without the nut 64. This facilitates the work of assembling the drape 6. The through holes of the frame members 61A and 61B may be elongated holes as in the first through hole 65. In this case, the frame material 61B and the bolt 63 are fixed by a nut 64, welding, or the like.

The frame materials 61A and 61B are preferably made of stainless steel (SUS304, SUS410, SUS430, etc. described in JIS G4304: 2012) from the viewpoint of heat resistance, workability, strength and the like. The material of the frame materials 61A and 61B is not limited to stainless steel, and may be a non-metal material such as ceramic or carbon material from the above viewpoint. Incidentally, SUS304, SUS410, the thermal expansion coefficient of SUS430 is respectively ^{17.3 × 10 -6 /K,9.9×10 -6 /K,10.4×10 -6} / K.

The thickness of the frame materials 61A and 61B is preferably 2 mm to 10 mm, more preferably 2 mm to 7 mm, still more preferably 2 mm to 4 mm. The heights of the frame materials 61A and 61B are preferably 70 mm to 110 mm, more preferably 80 mm to 100 mm.

The sheet portion 62 has a rectangular shape in the cross section of FIG. 2A. The material of the sheet portion 62 is preferably a non-metal material from the viewpoint of heat resistance, weight reduction and the like. As the non-metal material, a ceramic or carbon material is preferable from the viewpoint of rigidity, workability and the like. The material of the seat portion 62 may be stainless steel, which is different from the frame portion 61.

As the ceramic, a ceramic board obtained by molding a ceramic fiber into a plate shape, a mullite material, or the like is used.

The carbon material is preferably a CIP material or a C / C composite material. Here, the CIP material is a carbon material formed by using a cold isotropic pressure pressurization method (CIP method). The C / C composite material is a carbon composite material reinforced with high-strength carbon fibers. Both members are excellent in rigidity and workability. In particular, the C / C composite material is excellent in strength and rigidity, and is suitable for preventing deformation of the seat portion.

The C / C composite material preferably has a coefficient of thermal expansion of 1.0 × ^10-6 / K or less in the ^{direction parallel to the fiber, more preferably 0.8 × 10-6} / K or less, and 0.6 × 10 ^{−. 6} / K or less is more preferable. If the coefficient of thermal expansion is 1.0 × ^10-6 / K or less in the direction parallel to the fiber, the difference in the coefficient of thermal expansion of the material between the frame portion 61 and the seat portion 62 becomes large, so that the lower end of the seat portion and the glass The effect of the present invention that the gap with the ribbon is uniform in the width direction of the glass ribbon and the deformation of the sheet portion can be prevented can be fully exhibited. The coefficient of thermal expansion was measured using thermomechanical analysis (TMA).

The carbon material is preferably coated on its outer surface in order to prevent it from being oxidized by oxygen that has entered the dross box. Examples of the coating component include silicon carbide, aluminum, and oxides containing phosphorus. The thickness of the coating is, for example, 10 μm to 1 mm.

The non-metal material preferably has a bending strength of 90 MPa or more. The bending strength is more preferably 120 MPa or more, and even more preferably 140 MPa or more. The bending strength is preferably 300 MPa or less, more preferably 270 MPa or less, and even more preferably 250 MPa or less. The bending strength was measured using a three-point bending test. When the non-metal material was a C / C composite, it was measured using a JIS K 7078 shear test (test piece: 60 mm × 10 mm × thickness 3 mm).

When the bending strength is 90 MPa or more, the sheet portion 62 is less likely to be damaged, and the deformation of the sheet portion 62 can be better prevented. Further, when the bending strength is 300 MPa or less, even if the seat portion 62 is deformed, it is possible to suppress the deformation of the outer wall 31 (see FIG. 1) for suspending the drape 6.

The non-metallic material preferably has a bulk density of 2 g / cm ³ or less and a flexural modulus of 20 to 80 GPa. The bulk density is more preferably 1.8 g / cm ³ or less, 1.6 g / cm ³ or less is more preferred. The flexural modulus is more preferably 30 GPa to 70 GPa, and even more preferably 35 GPa to 65 GPa. The bulk density was measured using the Archimedes method. The flexural modulus is measured in the same manner as the bending strength described above.

When the bulk density is 2 g / cm ³ or less, the thickness of the seat portion 62 can be increased and the rigidity of the seat portion 62 can be increased without modifying the outer wall 31 (see FIG. 1) at the upper part of the dross box. can. Further, when the flexural modulus is 20 GPa or more, the deformation of the sheet portion 62 can be better prevented. When the flexural modulus is 80 GPa or less, even if the seat portion 62 is deformed, the restoring force of the seat portion 62 can be suppressed, so that the deformation of the outer wall 31 (see FIG. 1) for suspending the drape 6 can be suppressed. ..

The non-metal material preferably has a compressive strength of 90 MPa to 300 MPa and a tensile strength of 90 to 300 MPa from the viewpoint of preventing damage and deformation of the sheet portion 62. When the non-metal material was a C / C composite, the compressive strength was measured using an in-plane compression test of JIS K 7076, and the tensile strength was measured using a monofilament test.

The non-metallic material preferably has a coefficient of thermal expansion of 8 × 10 ^-6 / K or ^{less, more preferably 7 × 10 -6} / K or less, and even more preferably 6 × 10 ^-6 / K or less. When the coefficient of thermal expansion is 8 × 10 ^-6 / K or less, the difference in the coefficient of thermal expansion of the material between the frame portion 61 and the seat portion 62 becomes large, so that the above-mentioned effect of the present invention can be exhibited. The coefficient of thermal expansion was measured using thermomechanical analysis (TMA).

The thickness of the sheet portion 62 is preferably 0.8 mm to 15 mm, more preferably 1 mm to 10 mm, further preferably 1 mm to 7 mm, and particularly preferably 1.5 mm to 4 mm. The height of the seat portion 62 is preferably 250 mm to 500 mm, more preferably 300 mm to 400 mm.

As shown in FIGS. 2B and 3B, a plurality of bolts 63, which are vertically provided, are provided at intervals in the longitudinal direction of the drape 6. The number of bolts 63 may be three or more at the top and bottom.

The sheet portion 62 has three sheet materials (see FIG. 4). This is because the length of the drape 6 in the longitudinal direction is, for example, 5 m or more, and it is difficult to manufacture the sheet portion 62 with one sheet material. It is preferable that the sheet portion 62 is in contact with adjacent sheet materials in the longitudinal direction of the drape 6 so as to withstand the pressure of the atmosphere from the float bath. However, the sheet portion 62 may be provided with a gap between adjacent sheet materials as long as it can withstand the pressure. The number of sheet materials may be two or four or more.

Therefore, the drape 6 includes a joining plate 67 for joining the sheet material in the longitudinal direction of the drape 6, a bolt 68 for fastening the seat portion 62 and the joining plate 67, and a nut 69 for fixing the bolt 68 (FIG. 3 (FIG. 3). A) and). The joint plate 67 is preferably made of the same material as the sheet portion 62 in order to eliminate the difference in the coefficient of thermal expansion from the sheet portion 62.

The three bolts 68 arranged in a row in the vertical direction are provided at or near the end of the sheet material in the longitudinal direction of the drape 6. The number of bolts 68 arranged in a row in the vertical direction may be two or four or more.

As shown in FIGS. 2C and 3C, the first through hole 65 is a through hole corresponding to the bolt 63, and a plurality of first through holes 65 are provided at intervals in the longitudinal direction of the drape 6.

Here, the drape 6 is heated from room temperature to 550 ° C. or higher before starting the production of the float glass. Further, when the drape 6 is replaced after the production of the float glass is started, the newly installed drape 6 is heated from room temperature to 550 ° C. or higher.

Therefore, although the materials of the frame portion 61 and the seat portion 62 constituting the drape are different, if the first through hole 65 is a round hole, the seat portion uses the bolt 63 due to the difference in the coefficient of thermal expansion of both materials. It is constrained to the first through hole through. Then, the sheet portion is deformed without uniformly expanding in the longitudinal direction of the drape 6 (the width direction of the glass ribbon), and the gap between the lower end of the sheet portion and the glass ribbon becomes non-uniform in the width direction of the glass ribbon.

Therefore, the first through hole 65 is an elongated hole having a long side in the longitudinal direction of the drape 6. As a result, even if the materials of the frame portion 61 and the seat portion 62 are different, the seat portion 62 can move in the longitudinal direction of the drape 6 without being restrained by the first through hole 65 via the bolt 63. Therefore, the sheet portion 62 expands without being uniformly deformed in the longitudinal direction of the drape 6 (the width direction of the glass ribbon), and the gap between the lower end of the sheet portion 62 and the glass ribbon becomes uniform in the width direction of the glass ribbon.

The shape of the elongated hole is rectangular, the rectangular corner is C-chamfered, and the rectangular corner is R-chamfered from the viewpoint that the seat portion 62 is not constrained by the first through hole 65 via the bolt 63. Rounded rectangular shape) is preferable. From the above viewpoint, the shape of the elongated hole is a shape in which a part of the corner of the rectangle is C-chamfered, a shape in which a part of the corner of the rectangle is R-chamfered, and a part of the corner of the rectangle is C-chamfered. The shape may be such that all or part of the rest is R-chamfered. The shape of the elongated hole of the present embodiment is a shape in which the corners of the rectangle are chamfered (rounded rectangular shape).

The length of the long side of the long hole is preferably 1.5 times or more, preferably 2 times or more the length of the short side of the long hole in order to secure the movement of the frame portion 61 and the seat portion 62 in the longitudinal direction of the drape 6. Is more preferable, and 3 times or more is further preferable. Further, the length of the long side of the long hole is preferably 20 times or less the length of the short side of the long hole so that the first through hole 65 can be densely arranged at intervals in the longitudinal direction of the drape 6. , 18 times or less is more preferable, and 15 times or less is further preferable.

On the other hand, the through hole corresponding to the bolt 68 is a round hole. This is based on the premise that the seat portion 62 and the joint plate 67 are made of the same material. Therefore, when the materials of the sheet portion 62 and the joint plate 67 are different, the through hole is preferably a long hole like the first through hole 65.

When the sheet portion 62 can be manufactured from one sheet material, the drape does not have the through holes corresponding to the joint plate 67, the bolt 68, the nut 69, and the bolt 68 described above.

FIG. 4 is an overall view of the seat portion of FIGS. 2 (C) and 3 (C).

The seat portion 62 further has a second through hole 66 into which the bolt 63 is inserted. The second through hole 66 is a round hole and is provided at the center of the drape 6 in the longitudinal direction. As a result, the seat portion 62 is restrained by the second through hole 66 via the bolt 63, and the seat portion 62 is moved in the longitudinal direction of the drape 6 due to the difference in the coefficient of thermal expansion of the material between the frame portion 61 and the seat portion 62. It expands toward the outside (in the width direction of the glass ribbon) without being uniformly deformed. Then, the gap between the lower end of the sheet portion 62 and the glass ribbon becomes more uniform in the width direction of the glass ribbon.

Therefore, it is preferable that the position of the second through hole 66 in the height direction coincides with the position of the first through hole 65. Further, the position of the second through hole 66 is not limited to the center in the longitudinal direction of the drape 6, and may be near the center. There are two second through holes 66 at the top and bottom, but there may be three or more.

(Modified example of drape)
FIG. 5 is a diagram showing a modified example 1 of the drape of FIG. 2 (A).

The drape 60 has a bolt 630 having a shape different from that of the bolt 63 described above. The bolt 630 is a stepped bolt. The portion of the bolt 630 that is inserted through the frame member 61A and the seat portion 62 is thicker than the portion that is inserted through the frame member 61B. Further, the through hole of the frame material 61A is a mere round hole, whereas the through hole of the frame material 61B is a round hole and a screw hole.

Therefore, unlike the drape 6 described above, the drape 60 can fix the bolt 630 without the nut. This facilitates the work of assembling the drape 60.

If the through hole of the frame material 61B is not a screw hole, the frame material 61B and the bolt 630 may be welded and fixed.

FIG. 6 is a diagram showing a modified example 2 of the drape of FIG. 2 (A).

The drape 600 is different from the above-mentioned drape 6 in that the heat-resistant fiber sheet 601 and the seat support portion 602 are provided below the seat portion 62.

The heat-resistant fiber sheet 601 is fixed by a sheet support portion 602 provided on the upstream surface of the sheet portion 62. The seat support portion 602 has an angled shape. The heat-resistant fiber sheet 601 is sandwiched between the seat portion 62 and the seat support portion 602, and is fixed by using bolts or the like.

The lower end of the heat-resistant fiber sheet 601 projects downward from the lower end of the sheet portion 62 and is in contact with the upper surface of the glass ribbon. This makes it possible to prevent oxygen in the slow cooling furnace from entering the dross box and the float bath. Therefore, when tin or a tin alloy is used as the metal used for the molten metal M (see FIG. 1), it is possible to prevent the tin adhering to the lower surface of the glass ribbon from reacting with oxygen to become tin oxide (dross defect). .. Further, the heat-resistant fiber sheet 601 can remove tin-based foreign matter called top specs adhering to the upper surface of the glass ribbon by coming into contact with the upper surface of the glass ribbon.

The heat-resistant fiber sheet 601 is preferably a fiber made of a material that can withstand a temperature of 750 ° C. or higher. Specifically, it is an inorganic fiber such as carbon fiber, silica fiber, alumina fiber, silicon carbide fiber, and metal fiber. In particular, carbon fiber has a low hardness, so it is difficult to scratch the glass ribbon, and it repels molten tin, so it is easy to remove the top specifications. The heat-resistant fiber sheet 601 may be a fiber sheet containing two or more kinds of inorganic fibers made of different materials.

As the fiber sheet, a felt-like sheet or a woven cloth-like sheet is preferable. Specifically, a carbon fiber felt-like sheet (carbon felt), a carbon fiber woven cloth-like sheet (carbon cloth), or the like can be used.

The thickness of the heat-resistant fiber sheet 601 is preferably 5 mm to 20 mm from the viewpoint of flexibility, atmosphere blocking, and the like.

The heat-resistant fiber sheet 601 and the sheet support portion 602 may be provided on the downstream surface of the sheet portion 62, unlike FIG.

7A and 7B are views showing a modified example 3 of the drape of FIG. 2A, in which FIG. 7A is a state before the start of manufacturing the float glass, and FIG. 7B is a state when the float glass is being manufactured. It is a figure which shows.

The drape 700 is different from the drape 6 described above in that the seat portion 620 has a first seat portion 62A and a second seat portion 62B, and further has a movable joint plate 701.

As shown in FIG. 7A, the seat portion 620 has a first seat portion 62A fastened to the frame portion 61 and a second seat portion 62B below the first seat portion 62A. The lower end of the first seat portion 62A is in contact with the upper end of the second seat portion 62B. The lower end of the first sheet portion 62A may form a gap between the lower end and the upper end of the second sheet portion 62B.

By having the second sheet portion 62B, the sheet portion 620 projects downward from the lower end of the above-mentioned sheet portion 62 so as to come into contact with the upper surface of the glass ribbon. As a result, oxygen in the slow cooling furnace can be prevented from entering the dross box and the float bath, and the occurrence of dross defects can be suppressed. However, if the second sheet portion 62B is brought into contact with the upper surface of the glass ribbon, the glass ribbon may be broken.

Therefore, the drape 700 further has a movable joining plate 701 that joins the first seat portion 62A and the second seat portion 62B using bolts or the like. As the movable joint plate 701, a hinge or the like is used. The position of the hinge fulcrum of the movable joint plate 701 in the height direction is the same as the portion where the first seat portion 62A and the second seat portion 62B are in contact with each other. As a result, as shown in FIG. 7B, when the second seat portion 62B comes into contact with the upper surface of the glass ribbon, it rotates and moves downstream about the hinge fulcrum. Therefore, the stress generated in the glass ribbon is reduced, and the possibility that the glass ribbon is broken can be eliminated. When a gap is formed between the lower end of the first seat portion 62A and the upper end of the second seat portion 62B, the position of the hinge fulcrum in the height direction is the same as the gap.

The second sheet portion 62B is preferably a carbon material, more preferably a CIP material or a C / C composite material, from the viewpoint of suppressing stress generated in the glass ribbon.

(Float glass manufacturing method)
Next, the float glass manufacturing method according to the embodiment of the present invention will be described again with reference to FIGS. 1 and 2.

In the float glass manufacturing method, a glass raw material supplied to a melting kiln (not shown) is heated to obtain molten glass, and then the molten glass is poured into a float bath 10. Then, as shown in FIG. 1, a strip-shaped glass ribbon G is formed on the molten metal M of the float bath 10, and the glass ribbon G is pulled out from the float bath 10 by a lift-out roll 4 provided in the dross box 30. , The glass ribbon G is slowly cooled in the slow cooling furnace 20.

The dross box 30 has a drape 6 on top of a plurality of lift-out rolls 4 that convey the glass ribbon G.

As shown in FIG. 2A, the drape 6 has a seat portion 62, a frame portion 61 that sandwiches the upper portion of the seat portion 62, and a bolt 63 that fastens the seat portion 62 and the frame portion 61. The seat portion 62 is made of a different material from the frame portion 61 and has a first through hole 65 (see FIG. 2C) into which the bolt 63 is inserted. The first through hole 65 is an elongated hole having a long side in the longitudinal direction of the drape 6.

As a result, even if the materials of the frame portion 61 and the seat portion 62 are different, the seat portion 62 can move in the longitudinal direction of the drape 6 without being restrained by the first through hole 65 via the bolt 63. Therefore, the sheet portion 62 expands without being uniformly deformed in the longitudinal direction of the drape 6 (the width direction of the glass ribbon), and the gap between the lower end of the sheet portion 62 and the glass ribbon becomes uniform in the width direction of the glass ribbon.

The manufactured float glass is used, for example, as a glass substrate for a display, a cover glass for a display, and a window glass.

When the float glass produced is used as a glass substrate for a display, it is preferably non-alkali glass that does not substantially contain an alkali metal oxide. Here, the fact that the alkali metal oxide is substantially not contained means that the total content of the contents of _{Na 2} O, K ₂ O, and Li _{2 O is 0.1% by mass or less.}

For non-alkali glass, for example, in _{terms of mass% based on oxide, SiO 2} : 50% to 73%, Al ₂ O ₃ : 10.5% to 24%, B ₂ O ₃ : 0% to 12%, MgO : 0% to 10%, CaO: 0% to 14.5%, SrO: 0% to 24%, BaO: 0% to 13.5%, MgO + CaO + SrO + BaO: 8% to 29.5%, ZrO ₂ : 0% Contains ~ 5%.

In the case of achieving both high strain point and high solubility, the non-alkali glass is preferably expressed in mass% based on oxide, SiO ₂ : 58% to 66%, Al ₂ O ₃ : 15% to 22%, B ₂ O ₃ : 5% to 12%, MgO: 0% to 8%, CaO: 0% to 9%, SrO: 3% to 12.5%, BaO: 0% to 2%, MgO + CaO + SrO + BaO: 9% to Contains 18%.

When it is desired to obtain a particularly high strain point, the non-alkali glass is preferably expressed in terms of mass% based on oxide, SiO ₂ : 54% to 73%, Al ₂ O ₃ : 10.5% to 22.5%, B ₂ O ₃ : 0% to 5.5%, MgO: 0% to 10%, CaO: 0% to 9%, SrO: 0% to 16%, BaO: 0% to 2.5%, MgO + CaO + SrO + BaO: 8 Contains% to 26%.

Since the non-alkali glass having the above glass composition has a strain point 100 ° C. or higher higher than that of the soda lime glass used for the window glass, the atmospheric temperature in the dross box 30 is 650 ° C. or higher, depending on the glass composition. It can reach 700 ° C or higher. Then, the amount of thermal expansion of the frame portion 61 and the seat portion 62 increases. Therefore, in the above-mentioned float glass manufacturing method, even if the amount of thermal expansion of the frame portion 61 and the sheet portion 62 is large, the gap between the lower end of the sheet portion 62 and the glass ribbon can be made uniform in the width direction of the glass ribbon. Suitable for the production of alkaline glass.

The thickness of the manufactured float glass is 0.1 mm to 2.0 mm for cover glass applications and 0.1 mm to 0.7 mm for display glass substrate applications.

The substrate size of the float glass to be manufactured is preferably 2100 mm or more on the short side and 2400 mm or more on the long side, more preferably 2800 mm or more on the short side and 3000 mm or more on the long side, and 2900 mm or more on the short side and 3200 mm on the long side for glass substrate applications for liquid crystal displays. The above is more preferable.

Based on the above, in the float glass manufacturing apparatus and the float glass manufacturing method of the present invention, even if the materials of the frame portion and the sheet portion constituting the drape are different, the gap between the lower end of the sheet portion and the glass ribbon is the glass ribbon. It is uniform in the width direction and can prevent deformation of the seat portion.

As a result, oxygen in the slow cooling furnace can be suppressed from entering the dross box and the float bath, and eventually the occurrence of dross defects can be suppressed. Further, since the deformation of the drape is suppressed, the drape replacement work becomes unnecessary, and the production loss at the time of the replacement work can be prevented.

The present invention is not limited to the above embodiment, and various modifications and improvements can be made within the scope of the gist of the invention described in the claims.

Applications of the manufactured float glass include construction, vehicle, flat panel display, cover glass, and various other uses.

1 Float glass manufacturing equipment 10 Float bath 12 Bath surface 13 Outlet 18 Heater 20 Slow cooling furnace 21 Transport roll 23 Inlet 28 Heater 30 Dross box 31 Outer wall 32 Inner wall 33, 34 Insulation material 35-38 Space 39 Outlet 4 Lift out roll 5 Contact member 6 , 60, 600, 700 Drape 61 Frame part 61A, 61B Frame material 62, 620 Seat part 62A First seat part 62B Second seat part 63, 630 Bolt 64 Nut 65 First through hole 66 Second through hole 67 Joint plate 68 Bolt 69 Nut 601 Heat-resistant fiber sheet 602 Seat support 701 Movable joint plate 8 Heater G Glass ribbon M Float metal

Claims (15)

Float glass provided with a float bath for accommodating the molten metal, a slow cooling furnace in which a glass ribbon formed in a strip shape on the molten metal is carried in, and a dross box provided between the float bath and the slow cooling furnace. It ’s a manufacturing device,
The dross box has a drape on top of a plurality of lift-out rolls that carry the glass ribbon.
The drape has a seat portion, a frame portion that sandwiches the upper portion of the seat portion, and a bolt that fastens the seat portion and the frame portion.
The seat portion is made of a different material from the frame portion, and has a first through hole through which the bolt is inserted.
The float glass manufacturing apparatus, wherein the first through hole is an elongated hole having a long side in the longitudinal direction of the drape. The seat portion further has a second through hole through which the bolt is inserted.
A plurality of the first through holes are provided at intervals in the longitudinal direction of the drape.
The float glass manufacturing apparatus according to claim 1, wherein the second through hole is a round hole and is provided at the center in the longitudinal direction of the drape. The float glass manufacturing apparatus according to claim 1 or 2, wherein the bolt is a stepped bolt. The float glass manufacturing apparatus according to any one of claims 1 to 3, wherein the material of the sheet portion is a non-metallic material. The float glass manufacturing apparatus according to claim 4, wherein the non-metal material is ceramic. The float glass manufacturing apparatus according to claim 4, wherein the non-metal material is a carbon material. The float glass manufacturing apparatus according to claim 6, wherein the carbon material is a CIP material or a C / C composite material. The carbon material has a coating on the outer surface.
The float glass manufacturing apparatus according to claim 6 or 7, wherein the component of the coating is silicon carbide or an oxide containing aluminum and phosphorus. The float glass manufacturing apparatus according to any one of claims 4 to 8, wherein the non-metal material has a bending strength of 90 MPa or more. The float glass manufacturing apparatus according to any one of claims 4 to 9, wherein the non-metal material has a bulk density of 2 g / cm ^{3 or less and a flexural modulus of 20 GPa to 80 GPa.} The float glass manufacturing apparatus according to any one of claims 1 to 10, wherein the sheet portion has a thickness of 0.8 mm to 15 mm. The drape further has a heat-resistant fiber sheet and a sheet support portion below the sheet portion.
The heat-resistant fiber sheet is sandwiched between the sheet portion and the sheet support portion provided on the side surface of the sheet portion.
The float glass manufacturing apparatus according to any one of claims 1 to 11, wherein the lower end of the heat-resistant fiber sheet projects downward from the lower end of the sheet portion and is in contact with the upper surface of the glass ribbon. The seat portion has a first seat portion to be fastened to the frame portion and a second seat portion below the first seat portion.
The drape further comprises a movable joining plate for joining the first sheet portion and the second sheet portion.
The float glass manufacturing apparatus according to any one of claims 1 to 11, wherein the second sheet portion is in contact with the upper surface of the glass ribbon. A surveillance camera provided outside the side wall portion of the dross box and for photographing the drape and the glass ribbon in the dross box from the window of the side wall portion is further provided.
The image taken by the surveillance camera is subjected to image processing.
The float glass manufacturing apparatus according to any one of claims 1 to 13, wherein the distance between the drape and the glass ribbon in the width direction of the glass ribbon is measured by the image processing. A method for producing float glass in which a strip-shaped glass ribbon is formed on the molten metal of a float bath, the glass ribbon is pulled out from the float bath by a lift-out roll provided in a dross box, and the glass ribbon is slowly cooled in a slow cooling furnace. And
The dross box has a drape on top of a plurality of lift-out rolls that carry the glass ribbon.
The drape has a seat portion, a frame portion that sandwiches the upper portion of the seat portion, and a bolt that fastens the seat portion and the frame portion.
The seat portion is made of a different material from the frame portion, and has a first through hole through which the bolt is inserted.
The float glass manufacturing method, wherein the first through hole is an elongated hole having a long side in the longitudinal direction of the drape.

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