JP2016098161A - Float glass manufacturing apparatus and float glass manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a float glass manufacturing apparatus capable of suppressing the width direction oscillation of a glass ribbon on the downstream side of a forming area.SOLUTION: A float glass manufacturing apparatus of one aspect of the present invention comprises a float bath having a bottom storing a molten metal. The float bath includes a plurality of top rolls that presses an end part in the width direction of a glass ribbon to support the glass ribbon, and a plurality of heaters installed above the bottom. An area arranged with the heaters has a plurality of compartments divided along the transfer direction and the width direction when seeing the float bath from above. Sectioning lines between the compartments adjacent in the width direction includes inner sectioning lines located inside in the width direction than the top rolls in an area where the viscosity of the glass ribbon is 10dPa s or more and 10dPa s or less. The width direction distance between the inner sectioning line and the top roll is 100 mm or more and 350 mm or less.SELECTED DRAWING: Figure 5

Description

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

  For example, in Patent Document 1, a heater region in which a plurality of heaters are provided is partitioned in the moving direction and the width direction of the glass ribbon, a plurality of heaters are provided in each partition, and a plurality of heaters provided in one partition correspond. A float glass manufacturing apparatus that collectively controls with a single controller is described.

JP 2011-225386 A

  By the way, in the above float glass manufacturing apparatuses, a glass ribbon is conveyed by pulling a glass ribbon from the downstream side of a float bath, supporting the edge part of the glass ribbon in the width direction with a top roll.

  Since the viscosity of the glass ribbon is high on the downstream side of the glass ribbon forming region, it is difficult to support the end portion in the width direction of the glass ribbon by the top roll. Thereby, if the force pulling the glass ribbon from the downstream side is biased, the glass ribbon may swing in the width direction on the downstream side of the forming region. When the position of the glass ribbon is swung in the width direction, there is a possibility that the thickness of the glass ribbon varies.

  One aspect of the present invention is made in view of the above problems, and a float glass manufacturing apparatus and a float glass manufacturing capable of suppressing the glass ribbon from swinging in the width direction on the downstream side of the forming region. One of the purposes is to provide a method.

One aspect of the float glass manufacturing apparatus of the present invention includes a float bath having a bottom in which molten metal is stored, and continuously supplies molten glass on the surface of the molten metal to form a glass ribbon, A float glass manufacturing apparatus for transporting a glass ribbon in a transport direction, wherein the float bath presses end portions of the glass ribbon in a width direction perpendicular to the transport direction from above to support the glass ribbon. A region having a roll, a plurality of heaters provided above the bottom, and a plurality of control devices for controlling the heaters, and the heater is disposed when the float bath is viewed from above, It has a plurality of sections divided along the transport direction and the width direction, and the control device is provided for each of the sections and is provided in the corresponding section. Controlled collectively a plurality of said heaters, sectioning line between the compartments adjacent to each other in the width direction, the viscosity of the glass ribbon ¹⁰ 5.7 dPa · s or ^{more, 10} 7.5 dPa · In an area that is less than or equal to s, an inner dividing line positioned inside the width direction from the top roll is included, and a distance in the width direction between the inner dividing line and the top roll is 100 mm or more and 350 mm or less. It is characterized by that.

  The inner dividing line may be a dividing line between a first section provided at both ends in the width direction among the plurality of sections and a second section adjacent to the first section in the width direction. Good.

In the first section, the output of the heater in a section included in a region where the viscosity of the glass ribbon is 10 ^5.7 dPa · s or more and 10 ^7.5 dPa · s or less is 30 kW / m ² or more. It is good also as a structure.

In the second section, the output of the heater in a section included in a region in which the viscosity of the glass ribbon is 10 ^5.7 dPa · s or more and 10 ^7.5 dPa · s or less is 20 kW / m ² or more. It is good also as a structure.

  The number of the sections arranged in the width direction may be an odd number.

  At least one set of the sections adjacent to each other in the transport direction may be shifted in the width direction.

One aspect of the float glass manufacturing method of the present invention is to supply molten glass continuously on the surface of the molten metal stored in the float bath to form a glass ribbon, and transport the glass ribbon in the transport direction. A float glass manufacturing method, using a plurality of top rolls, pressing an end of the glass ribbon in the width direction perpendicular to the conveying direction from above to support the glass ribbon, and using a plurality of heaters Heating the glass ribbon, and the region where the heater is disposed when the float bath is viewed from above includes a plurality of sections divided along the transport direction and the width direction. The plurality of heaters provided in the compartments are collectively controlled for each of the compartments, and a dividing line between the compartments adjacent in the width direction is The viscosity of Suribon is ¹⁰ 5.7 dPa · s or ^more, in a region equal to or less than ¹⁰ 7.5 dPa · s, comprising an inner sectioning line located on the inner side of the width direction than the top roll, and the inner sectioning line The distance in the width direction with respect to the top roll is 100 mm or more and 350 mm or less.

  According to one aspect of the present invention, there are provided a float glass manufacturing apparatus and a float glass manufacturing method capable of suppressing the glass ribbon from swinging in the width direction on the downstream side of the forming zone.

It is sectional drawing which shows the part of the float glass manufacturing apparatus of this embodiment. It is a top view which shows the float bath of this embodiment. It is a top view which shows the float bath of this embodiment. It is a top view which shows the top roll of this embodiment. It is sectional drawing which shows the top roll of this embodiment.

Hereinafter, a float glass manufacturing apparatus and a float glass manufacturing method according to an embodiment of the present invention will be described with reference to the drawings.
The scope of the present invention is not limited to the following embodiment, and can be arbitrarily changed within the scope of the technical idea of the present invention. Moreover, in the following drawings, in order to make each structure easy to understand, the actual structure may be different from the scale, number, or the like in each structure.

  In the drawings, an XYZ coordinate system is appropriately shown as a three-dimensional orthogonal coordinate system, the Z-axis direction is the vertical direction, the X-axis direction is the length direction of the float bath 10 shown in FIG. 2, and the Y-axis direction is the float bath. The width direction is 10. The length direction of the float bath 10 is the left-right direction in FIG. 2, and in this specification is the conveyance direction of the glass ribbon GR. Moreover, the width direction of the float bath 10 is the left-right direction in FIG. 2, and is the width direction orthogonal to the conveyance direction of the glass ribbon GR.

In the present specification, the conveyance direction of the glass ribbon GR is a direction in which the glass ribbon GR is conveyed in a plan view.
Moreover, in this specification, an upstream side and a downstream side are with respect to the conveyance direction (X-axis direction) of the glass ribbon GR in the float glass manufacturing apparatus 1. FIG. That is, in this specification, the + X side is the downstream side, and the -X side is the upstream side.

  In the present specification, the inner side in the width direction (Y-axis direction) is the side where the center of the float bath 10 in the width direction is located in the width direction. In this specification, the outside in the width direction is the side opposite to the side where the center of the float bath 10 is located in the width direction.

  In the following description, unless otherwise specified, the width direction means the width direction of the float bath 10 and the width direction of the glass ribbon GR, and the transport direction refers to the transport direction of the glass ribbon GR. Shall mean.

  FIG. 1 is a cross-sectional view (ZX cross-sectional view) showing a portion of the float glass manufacturing apparatus 1 of the present embodiment. 2 and 3 are plan views showing the float bath 10. 2 and 3, the roof 11b is not shown. Moreover, in FIG. 3, illustration of the top rolls 20-29 is abbreviate | omitted.

  As shown in FIG. 1, the float glass manufacturing apparatus 1 according to the present embodiment includes a float bath 10 having an internal space AR. Moreover, the float glass manufacturing apparatus 1 includes a melting furnace (not shown) and a slow cooling furnace (not shown).

  The float bath 10 is a device that forms the glass ribbon GR in the internal space AR. A melting furnace (not shown) is connected to the upstream side (−X side) of the float bath 10. The melting furnace supplies the molten glass Gm onto the surface Ma of the molten metal M stored in the float bath 10 from the upstream side via the lip 19. The molten glass Gm is continuously supplied onto the surface Ma of the molten metal M while the flow rate is controlled by the twill 18.

  A slow cooling furnace (not shown) is connected to the downstream side (+ X side) of the float bath 10. The slow cooling furnace cools the glass ribbon GR formed by the float bath 10. The slow cooling furnace is provided with a plurality of transport rolls, for example. The glass ribbon GR is transported from the upstream side (−X side) to the downstream side by being pulled downstream by the transport roll of the slow cooling furnace.

  That is, the float glass manufacturing apparatus 1 continuously supplies the molten glass Gm on the surface Ma of the molten metal M stored in the float bath 10 to form the glass ribbon GR, and transfers the glass ribbon GR in the transport direction (X axis). Direction).

  The float bath 10 includes a bottom 11a, a roof 11b, a plurality of heaters 30, and a plurality of control devices 40. The float bath 10 has a plurality of top rolls 20 to 29 as shown in FIG.

As shown in FIG. 1, molten metal M is stored in the bottom 11a. The roof 11b covers the upper side (+ Z side) of the bottom 11a. The plurality of heaters 30 are provided on the roof 11b. The plurality of heaters 30 are controlled by the control device 40 and can heat the glass ribbon GR formed on the molten metal M.
Hereinafter, each part of the float bath 10 will be described in detail.

(bottom)
The bottom 11 a includes a bottom main body 12 and a bottom casing 13.
On the upper (+ Z side) surface of the bottom main body 12, a storage tank 12 a that is concave on the lower side (−Z side) is formed. The molten metal M is stored in the storage tank 12a. The molten metal M is, for example, molten tin, molten tin alloy, or the like. The material of the bottom body 12 is, for example, clay bricks.

  The bottom casing 13 covers the outer surface of the bottom main body 12. The bottom casing 13 is made of steel, for example.

(roof)
The roof 11b is disposed on the upper side (+ Z side) of the bottom 11a. The roof 11 b includes a roof casing 15 and a roof brick layer 16.

  The roof casing 15 is suspended from an upper structure (not shown) such as a beam of a building where the float bath 10 is installed. The roof casing 15 has a box shape that opens downward (−Z side). The roof casing 15 is provided with a gas inlet (not shown). The roof casing 15 is made of steel, for example.

  A sidewall (not shown) is fixed inside the lower (−Z side) portion of the roof casing 15. The material of the sidewall is, for example, a heat insulating brick, sillimanite or the like.

  The roof brick layer 16 is provided inside a sidewall (not shown). The roof brick layer 16 is configured by placing a substantially rectangular parallelepiped brick block called PBA on a framework that is assembled in a lattice shape (not shown). The framework assembled in a lattice shape is suspended from, for example, the top surface inside the roof casing 15. Thereby, the roof brick layer 16 is arrange | positioned in desired height.

The roof brick layer 16 divides the internal space AR of the float bath 10 into a lower space AR1 and an upper space AR2.
The lower space AR1 is a space located between the bottom 11a and the roof 11b in the internal space AR of the float bath 10. The lower space AR1 is in contact with the molten metal M and the glass ribbon GR formed on the molten metal M.

  The upper space AR2 is a space located inside the roof 11b in the internal space AR of the float bath 10. The upper space AR2 is located on the upper side (+ Z side) of the roof brick layer 16 and a sidewall (not shown). The upper space AR2 communicates with the lower space AR1 through a through hole provided in the roof brick layer 16.

  Although illustration is omitted, a side seal is provided between the bottom 11a and the roof 11b in the vertical direction. The side seal seals the gap in the vertical direction between the bottom 11a and the roof 11b. Thereby, a substantially sealed internal space AR surrounded by the bottom 11a, the roof 11b, and a side seal (not shown) is formed.

(heater)
The plurality of heaters 30 are provided above the bottom 11a. In the float bath 10, for example, several thousand heaters 30 are installed. The plurality of heaters 30 extend in the vertical direction (Z-axis direction). The plurality of heaters 30 are installed through the roof brick layer 16. In the present embodiment, the plurality of heaters 30 are, for example, solid cylindrical shapes. The material of the plurality of heaters 30 is, for example, silicon carbide (SiC).

  As shown in FIG. 3, the heater region ARH in which the plurality of heaters 30 are arranged when the float bath 10 is viewed from above is a conveyance direction (X-axis direction) of the glass ribbon GR formed on the molten metal M, And it has the some division divided along the width direction (Y-axis direction) orthogonal to a conveyance direction. In the example illustrated in FIG. 3, the heater region ARH is divided into rows A to H along the conveyance direction, and rows B to G are divided into five sections along the width direction. Details will be described later.

A plurality of heaters 30 are provided in each section. The plurality of heaters 30 provided in one section are connected to the same control device 40. That is, the plurality of heaters 30 provided in one section are collectively controlled by one control device 40. The plurality of heaters 30 in the section are installed so that, for example, the amount of heat radiated from the plurality of heaters 30 toward the glass ribbon GR is substantially uniform in one section.
In the present embodiment, the heater area ARH is an area located inside the storage tank 12a when viewed from above.

(Control device)
The control device 40 controls the heater 30. The control device 40 is provided for each section of the heater region ARH described above. The control device 40 collectively controls the plurality of heaters 30 provided in the corresponding sections. The configuration of the control device 40 is not particularly limited as long as the outputs of the plurality of heaters 30 in one section can be adjusted collectively.

(Top roll)
As shown in FIG. 2, the plurality of top rolls 20 to 29 are disposed opposite to each other in the width direction (Y-axis direction) of the glass ribbon GR. The top rolls 20 to 29 prevent the width of the glass ribbon GR from being narrowed by the surface tension. The number of installed top rolls is appropriately set according to molding conditions such as the type of glass and the target thickness. The number of installed top rolls is, for example, 4 pairs or more and 30 pairs or less, preferably 10 pairs or more and 30 pairs or less. In the example shown in FIG. 2, the top rolls are provided in a total of five pairs: top rolls 20 and 25, top rolls 21 and 26, top rolls 22 and 27, top rolls 23 and 28, and top rolls 24 and 29. As the plate thickness of the float glass to be manufactured is reduced, the number of installed top rolls tends to increase.

  In addition, since the structure of the top rolls 20-29 is the same structure except the point from which the provided position differs, in the following description, only the top roll 24 may be demonstrated as a representative.

These top rolls 20 to 29, more precisely, a top roll body described later, are provided in the forming area ARF of the glass ribbon GR. In this specification, the forming area ARF of the glass ribbon GR is an area where the viscosity of the glass ribbon GR is 10 ^4.5 dPa · s or more and 10 ^7.5 dPa · s or less. In the present embodiment, the molding area ARF corresponds to an area in which the columns B to G are provided in the heater region ARH.

The molding area ARF has an upstream molding area ARF1 and a downstream molding area ARF2.
The upstream molding area ARF1 is an area located on the upstream side (−X side) of the molding area ARF. The upstream molding area ARF1 is an area where the viscosity of the glass ribbon GR is 10 ^4.5 dPa · s or more and smaller than 10 ^5.7 dPa · s. In the present embodiment, the upstream molding area ARF1 corresponds to an area in which the columns B to E are provided in the heater region ARH. In the upstream molding area ARF1, the output of the heater 30 in each section of the rows B to E is adjusted, and the plate thickness of the glass ribbon GR is adjusted.

The downstream molding area ARF2 is an area located on the downstream side (+ X side) of the molding area ARF. The downstream molding area ARF2 is an area where the viscosity of the glass ribbon GR is 10 ^5.7 dPa · s or more and 10 ^7.5 dPa · s or less. That is, the viscosity of the glass ribbon GR in the downstream molding area ARF2 is higher than the viscosity of the glass ribbon GR in the upstream molding area ARF1. In the present embodiment, the downstream molding area ARF2 corresponds to an area where the rows F and G are provided in the heater area ARH.

  In the downstream molding area ARF2, the temperature of the glass ribbon GR whose thickness is adjusted in the upstream molding area ARF1 gradually decreases from the upstream side (−X side) toward the downstream side (+ X side). In addition, the output of the heater 30 in each section of the rows F and G is adjusted.

FIG. 4 is a cross-sectional view showing a state in which the top roll 24 provided on the most downstream side (+ X side) is fitted to the glass ribbon GR.
As shown in FIG. 4, the top roll 24 includes a top roll main body 24A that supports an end portion in the width direction (Y-axis direction) of the glass ribbon GR, and a rotary shaft 24B that is connected to the top roll main body 24A. Is done. When the rotary shaft 24B is rotationally driven by a driving device such as an electric motor, the top roll main body 24A rotates and feeds the end in the width direction of the glass ribbon GR to the downstream side.

  The top roll body 24A has a disk shape. The outer peripheral surface of the top roll body 24A comes into contact with the end portion in the width direction (Y-axis direction) of the glass ribbon GR from the upper side (+ Z side). A plurality of protrusions are provided along the circumferential direction on the outer peripheral surface of the top roll body 24A to prevent slippage. Thereby, the top roll 24 is fitted to the glass ribbon GR. The top roll 24 supports the glass ribbon GR by pressing the end in the width direction of the glass ribbon GR from above.

  By fitting the top roll body 24A to the glass ribbon GR, an ear portion GRe is formed at the end in the width direction (Y-axis direction) of the glass ribbon GR. The ear part GRe includes a fitting part GRe1 having a trace in which the top roll body 24A is fitted, and an outer part GRe2 located outside the fitting part GRe1. The central part GRc inside the ear part GRe in the glass ribbon GR is a part that is adjusted in thickness and becomes a product.

  The position where the top roll main body 24A is fitted to the glass ribbon GR is, for example, a position separated from the outer edge portion GRa of the glass ribbon GR by about 100 mm to 150 mm on the inner side (−Y side) in the width direction. In other words, the dimension in the width direction of the ear portion GRe of the glass ribbon GR is, for example, about 100 mm or more and 150 mm or less.

  The top roll body 24A is made of metal, for example. The inside of the top roll body 24A is water-cooled, for example, in order to suppress the adhesion between the top roll body 24A and the glass ribbon GR.

  The glass ribbon GR formed on the molten metal M is maintained in a state of being spread in the width direction (Y-axis direction) by the top rolls 20 to 29. That is, the shape of the glass ribbon GR, that is, the streamline of the glass ribbon GR is defined by the arrangement of the top rolls 20 to 29.

Hereinafter, the division method of the division will be described in detail.
As shown in FIG. 2, the heater region ARH is divided into a plurality of rows A to H along the conveyance direction (X-axis direction) of the glass ribbon GR. The number of this row | line | column is suitably set according to molding conditions, such as the kind of glass, the magnitude | size of the storage tank 12a. The number of rows is preferably about 4 or more and 15 or less, for example. If the number of rows is too small, it is difficult to sufficiently control the temperature distribution in the conveyance direction of the glass ribbon GR. On the other hand, if the number of rows is too large, the number of necessary control devices 40 increases, and the size of the float glass manufacturing apparatus 1 increases, and the management of the float glass manufacturing apparatus 1 becomes complicated.

  For example, as shown in FIG. 3, the rows B to G are divided into a plurality of sections along the width direction (Y-axis direction) of the glass ribbon GR. The plurality of sections are preferably arranged symmetrically with respect to the center line in the width direction of the glass ribbon GR.

  The number of sections in each row is appropriately set according to molding conditions such as the type of glass and the size of the storage tank 12a. The number of compartments per row is preferably 4 or more and 30 or less, more preferably 4 or more and 20 or less, and still more preferably 4 or more and 15 or less. If the number of the sections is too small, it is difficult to sufficiently control the temperature distribution in the transport direction of the glass ribbon GR. On the other hand, if the number of rows is too large, the number of necessary control devices 40 increases, and the size of the float glass manufacturing apparatus 1 increases, and the management of the float glass manufacturing apparatus 1 becomes complicated. In this embodiment, each column is divided into, for example, five sections. That is, in this embodiment, the number of sections arranged in the width direction (Y-axis direction) is an odd number.

  Here, two rows adjacent in the transport direction (X-axis direction) are divided by a dividing line PL1. The dividing line PL1 is located approximately at the center between the heaters 30 adjacent in the transport direction. On the other hand, two sections adjacent in the width direction (Y-axis direction) are divided by a dividing line PL2. The dividing line PL2 is located substantially at the center between the heaters 30 adjacent in the width direction of the glass ribbon GR. In the present embodiment, the dividing line PL1 is, for example, a straight line extending in the width direction. In the present embodiment, the dividing line PL2 is, for example, a straight line extending in the transport direction.

  In this embodiment, between two rows adjacent in the transport direction (X-axis direction), for example, at least one or more dividing lines are provided shifted in the width direction (Y-axis direction). Thereby, at least one set of the sections adjacent to each other in the transport direction is shifted in the width direction (Y-axis direction). The sections adjacent in the transport direction are, for example, sections F2 and G2, sections F4 and G4, and the like.

  In the present embodiment, the rows B to E located in the upstream molding area ARF1 are divided in the width direction (Y-axis direction) along predetermined flow lines FL1 and FL2 of the glass ribbon GR, for example.

  Here, the streamline of the glass ribbon GR means a flow path through which a predetermined portion in the width direction (Y-axis direction) of the glass ribbon GR constantly passes. The streamline of the glass ribbon GR includes the outline of the glass ribbon GR when viewed from above. For example, the predetermined flow lines FL1 and FL2 of the glass ribbon GR are flow paths corresponding to portions where the thickness of the glass ribbon GR is greatly deviated from the average value. In the present embodiment, the sections B2, C2, D2, E2, F2, and G2 overlap the streamline FL1. In the present embodiment, the sections B4, C4, D4, E4, F4, and G4 overlap the streamline FL2.

  The dividing line PL2 that divides the columns F and G located in the downstream molding area ARF2 includes inner dividing lines PL2a, PL2b, PL2c, and PL2d. In other words, the plurality of dividing lines PL2 between the sections adjacent in the width direction (Y-axis direction) include the inner dividing lines PL2a, PL2b, PL2c, and PL2d in the downstream molding area ARF2. In the present embodiment, the inner dividing lines PL2a to PL2d are between a first section provided at both ends in the width direction (Y-axis direction) and a second section adjacent to the first section in the width direction among the plurality of sections. It is a dividing line.

  Here, the first section in the example of FIG. 3 corresponds to the sections B1, B5, C1, C5... F1, F5, G1, G5. In the example of FIG. 3, the second section corresponds to the sections B2, B4, C2, C4... F2, F4, G2, G4.

  The inner dividing line PL2a is a dividing line between the first section F1 and the second section F2. The inner dividing line PL2b is a dividing line between the first section F5 and the second section F4. The inner dividing line PL2c is a dividing line between the first section G1 and the second section G2. The inner dividing line PL2d is a dividing line between the first section G5 and the second section G4.

  The inner division lines PL2a to PL2d have the same configuration except that the positions provided are different and the corresponding top rolls are different. Therefore, in the following description, only the inner division line PL2c will be described as a representative. There is a case.

FIG. 5 is a plan view for explaining the inner dividing line PL2c.
As shown in FIG. 5, the inner division line PL <b> 2 c is located on the inner side (−Y side) in the width direction than the top roll 24.

  In the present embodiment, the top roll body 24A of the top roll 24 is provided, for example, inclined with respect to the transport direction (X-axis direction). Therefore, the distance in the width direction (Y-axis direction) between the inner dividing line PL2c and the top roll 24 varies depending on the position in the transport direction. The shortest distance LT1 in the width direction between the inner division line PL2c and the top roll 24 is 100 mm or more. The longest distance LT2 in the width direction between the inner division line PL2c and the top roll 24 is 350 mm or less. That is, the distance in the width direction between the inner dividing line PL2c and the top roll 24 is 100 mm or more and 350 mm or less.

  The shortest distance LG1 in the width direction (Y-axis direction) between the inner dividing line PL2c and the outer edge portion GRa of the glass ribbon GR is, for example, 250 mm or more. The longest distance LG2 in the width direction between the inner dividing line PL2c and the outer edge GRa of the glass ribbon GR is, for example, 500 mm or less. That is, the distance in the width direction between the inner dividing line PL2c and the outer edge portion GRa of the glass ribbon GR is, for example, 250 mm or more and 500 mm or less.

In the present embodiment, the output of the heater 30 in the first section G1 located on the outer side in the width direction (+ Y side) of the inner section line PL2c is, for example, 30 kW / m ² or more. In other words, the output of the heater 30 in the section included in the downstream molding area ARF2 in the first section is, for example, 30 kW / m ² or more.

  By setting the output of the heater 30 in the first section G1 in this way, the ear portion GRe of the glass ribbon GR can be suitably heated. Thereby, the top roll 24 becomes easy to fit with the glass ribbon GR, and the swing of the glass ribbon GR in the width direction can be suppressed.

As an example, in the second section G2 located on the inner side (−Y side) in the width direction of the inner section line PL2c, the output of the heater 30 is, for example, 20 kW / m ² or more. In other words, the output of the heater 30 in the section included in the downstream molding area ARF2 in the second section is, for example, 20 kW / m ² or more.

  By setting the output of the heater 30 in the second section G2 in this way, it is easy to appropriately control the viscosity in the width direction (Y-axis direction) of the central portion GRc of the glass ribbon GR in the downstream molding area ARF2.

Next, the procedure of the float glass manufacturing method using the float glass manufacturing apparatus 1 will be described.
First, as shown in FIG. 1, molten glass Gm is caused to flow into a float bath 10 from a melting furnace (not shown). The molten glass Gm that has flowed into the float bath 10 flows on the surface Ma of the molten metal M from the upstream side (−X side) to the downstream side (+ X side) as a strip-like glass ribbon GR.

  And while heating the glass ribbon GR with the some heater 30, the edge part of the width direction (Y-axis direction) of the glass ribbon GR is supported with the some top rolls 20-29, and it sends out downstream (+ X side). At this time, reducing gas is introduced into the upper space AR2 from a gas inlet (not shown) provided in the roof casing 15.

The reducing gas to be introduced is, for example, hydrogen (H ₂ ). In the present embodiment, a mixed gas obtained by mixing an inert gas with hydrogen as a reducing gas is introduced into the upper space AR2. An example of the inert gas is nitrogen (N ₂ ).

The mixed gas introduced into the upper space AR2, that is, the reducing gas (H ₂ ) and the inert gas (N ₂ ), flows into the lower space AR1 through the through holes of the roof brick layer 16. Thereby, it can suppress that the molten metal M currently stored by the storage tank 12a of the bottom 11a is oxidized.

  In the forming area ARF, the glass ribbon GR is stretched in the transport direction (X-axis direction) by being pulled from the downstream side (+ X side) by a transport roll of a slow cooling furnace (not shown), and also in the width direction (Y (Axial direction). In addition, in the upstream molding area ARF1, the thickness of the glass ribbon GR is made uniform by making a difference in the output of the heater 30 for each section. In this way, the plate thickness of the glass ribbon GR is adjusted in the upstream molding area ARF1.

  As an example of the output adjustment of the heater 30 in the upstream molding area ARF1, there is an increase in the output of the heater 30 in a section located at a portion where the plate thickness of the glass ribbon GR is greatly deviated from the average value. In the present embodiment, the sections located at the portion where the plate thickness is greatly deviated from the average value are, for example, sections B2, B4, C2, C4... F2, F4, G2, G4 overlapping the streamlines FL1, FL2.

In the downstream molding area ARF2, the output of the heater 30 is adjusted so that the temperature of the glass ribbon GR whose plate thickness is adjusted in the upstream molding area ARF1 gradually decreases toward the downstream side (+ X side). . In the first sections F1, F5, G1, and G5 in the downstream molding area ARF2, the output of the heater 30 is set higher than those in the sections on the inner side of the first sections F1, F5, G1, and G5. Specifically, as described above, for example, the output of the heater 30 in the first sections F1, F5, G1, and G5 is set to 30 kW / m ² or more.

As shown in FIG. 1, the glass ribbon GR formed on the surface Ma of the molten metal M passes through the float bath 10 through an opening 10 a provided at the downstream end (+ X side) of the float bath 10. It is conveyed to a slow cooling furnace (not shown) connected to the downstream side. In the slow cooling furnace, the glass ribbon GR is cooled. The glass ribbon GR cooled in the slow cooling furnace is cut into a predetermined size by a cutting device to obtain a glass plate having a target size.
The float glass is manufactured as described above.

The float glass manufactured in this embodiment is, for example, alkali-free glass.
The alkali-free glass to be produced is, for example, expressed in mass% on the basis of oxide, SiO ₂ : 50% or more, 73% or less, Al ₂ O ₃ : 10.5% or more, 24% or less, 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% Hereinafter, MgO + CaO + SrO + BaO: 8% or more and 29.5% or less, ZrO ₂ : 0% or more and 5% or less are contained.

Further, as another example, the alkali-free glass to be produced is, for example, expressed in terms of mass% on the basis of oxide, SiO ₂ : 57% or more, 65% or less, Al ₂ O ₃ : 14% or more, 23% or less, B ₂ O ₃ : 0% to 5.5%, MgO: 1% to 8.5%, CaO: 3% to 12%, SrO: 0% to 10%, BaO: 0 %, 5% or less, MgO + CaO + SrO + BaO: 12% or more, 23% or less, ZrO ₂ : 0% or more, 5% or less. At this time, the glass transition point of the alkali-free glass is 730 ° C. or higher and 850 ° C. or lower. The viscosity of the alkali-free glass is 1220 ° C. or higher and 1350 ° C. or lower at a temperature of 10 ⁴ dPa · s.

  Moreover, the plate | board thickness of the float glass manufactured in this embodiment is not specifically limited, For example, it is 1.0 mm or less.

  According to the present embodiment, the distance in the width direction between the inner dividing line PL2c located in the downstream molding area ARF2 and the top roll 24 is 100 mm or more and 350 mm or less. Therefore, for example, by increasing the output of the heater 30 in the first section G1 on the outer side in the width direction of the inner section line PL2c, the portion of the glass ribbon GR where the top roll body 24A is fitted, that is, the ear portion of the glass ribbon GR. GRe can be heated to lower the viscosity. Thereby, in the downstream molding area ARF <b> 2, the top roll body 24 </ b> A is fitted deeper into the glass ribbon GR, and the glass ribbon GR can be stably supported by the top roll 24. Therefore, according to the present embodiment, the glass ribbon GR is arranged in the width direction on the downstream side of the forming area ARF, that is, in the downstream forming area ARF2 even when there is variation in the pulling from the downstream side by the transport roll of the slow cooling furnace. Can be suppressed.

  For example, if the distance in the width direction between the inner dividing line PL2c and the top roll 24 is large, the region of the central portion GRc of the glass ribbon GR included in the first section G1 becomes large. Therefore, when the output of the heater 30 in the first section G1 is increased, the central portion GRc that is a product is excessively heated, and the plate thickness of the central portion GRc adjusted in the upstream molding area ARF1 may vary. .

  On the other hand, according to the present embodiment, since the distance in the width direction between the inner division line PL2c and the top roll 24 is 100 mm or more and 350 mm or less, the region of the central part GRc included in the first section G1 is determined. Can be small. Thereby, even if it is a case where the output of the heater 30 in the 1st division G1 is enlarged, it can suppress that the center site | part GRc is heated too much. Therefore, according to the present embodiment, the ear portion GRe of the glass ribbon GR can be heated to suppress the swing of the glass ribbon GR in the width direction, and the central portion GRc to be a product is excessively heated to prevent the central portion GRc from being heated. It can suppress that board thickness fluctuates.

  Further, for example, in the downstream molding area ARF2, if the balance of the viscosity distribution at the central portion GRc is poor, the glass ribbon GR is not uniformly pulled from the downstream side, and the product thickness may vary. As an example, when there is a portion where the viscosity distribution in the width direction of the glass ribbon GR changes abruptly, the pulling method from the downstream side differs greatly on both sides in the width direction of the portion. Therefore, the plate thickness of the glass ribbon GR tends to fluctuate.

  On the other hand, according to the present embodiment, since the inner dividing line PL2c is provided in the vicinity of the inside of the top roll 24, the temperature control of the ear portion GRe of the glass ribbon GR and the temperature control of the central portion GRc Can be controlled independently of each other. Thereby, according to this embodiment, while optimizing the viscosity of the ear | edge part GRe of the glass ribbon GR, it is possible to adjust the viscosity distribution of the center region GRc more precisely.

As an example, by making the output of the heater 30 in the second section G2 partitioned by the inner section line PL2c relatively close to the output of the heater 30 in the first section G1, the viscosity distribution in the width direction of the glass ribbon GR Can be prevented from changing rapidly. Specifically, as described above, for example, the output of the heater 30 in the first section G1 can be set to 30 kW / m ² or more, and the output of the heater 30 in the second section G2 can be set to 20 kW / m ² or more.

  Further, according to the present embodiment, the inner dividing line PL2c is between the first section G1 provided at both ends in the width direction among the plurality of sections and the second section G2 adjacent to the first section G1 in the width direction. This is a dividing line. Therefore, by raising the output of the heater 30 in the first section G1, the ear portion GRe of the glass ribbon GR can be heated, and the molten metal M on the outer side in the width direction than the outer edge portion GRa of the glass ribbon GR can be heated.

Further, for example, when the dividing line is located at the center in the width direction of the glass ribbon GR, there is a possibility that unevenness occurs in heating at the center in the width direction of the glass ribbon GR.
On the other hand, in order to make the plate thickness of the glass ribbon GR uniform with high precision, it is preferable that the sections are arranged symmetrically with respect to the center line in the width direction.

  On the other hand, according to the present embodiment, the number of sections arranged in the width direction is an odd number. Therefore, each section can be set so that the dividing line is not positioned at the center in the width direction of the glass ribbon GR and each section is symmetric with respect to the center line in the width direction.

Moreover, according to this embodiment, at least one set of sections adjacent to each other in the transport direction is shifted in the width direction. Therefore, for example, in the rows F and G included in the downstream molding area ARF2, the inner dividing lines PL2a and PL2c can be appropriately set.
Further, since each section can be set along the predetermined flow lines FL1, FL2, the plate thickness can be adjusted more accurately in the upstream molding area ARF1.

  In the present embodiment, the following configurations and methods may be employed.

  In the present embodiment, the inner dividing line PL2c may not be a dividing line that divides the first section G1 and the second section G2. That is, one or more dividing lines may be provided on the inner side in the width direction than the inner dividing line PL2c.

  In the present embodiment, a plurality of inner division lines PL2c may be provided. That is, two or more inner dividing lines may be provided in a region of 100 mm or more and 350 mm or less on the inner side in the width direction from the top roll 24.

  Further, the division of the heater region ARH is not limited to the example described above, and is not particularly limited within a range including at least one inner division line PL2c.

  In the present embodiment, the configuration of the heater 30 is not limited to the configuration described above. The heater 30 may be, for example, a hollow heater or a quadrangular prism shape.

  In the present embodiment, the number and arrangement of the heaters 30 are not particularly limited.

  In the present embodiment, for example, the upper space AR2 may be partitioned in the width direction. In this case, for example, the upper space AR2 can be divided into three in the width direction by providing a partition member in the upper space AR2 along at least a part of the outer edge portion GRa of the glass ribbon GR.

According to this configuration, the reducing gas (H ₂ ) can be introduced into each space partitioned by the partition member. Therefore, for example, in the upper space AR2, the concentration of the reducing gas (H ₂ ) in the center space in the width direction is lower than the concentration of the reducing gas (H ₂ ) in the space at both ends in the width direction. A reducing gas (H ₂ ) can be introduced into the upper space AR2. Thereby, the concentration of the reducing gas (H ₂ ) is lowered above the glass ribbon GR, and the concentration of the reducing gas (H ₂ ) is raised above the molten metal M outside the width direction of the glass ribbon GR. be able to.

When, for example, tin (Sn) is used as the molten metal M, a part of the molten tin evaporates in the state of a compound such as an oxide and exists as a gas in the lower space AR1. When the reducing gas (H ₂ ) comes into contact with the gas of the tin compound, the tin compound is reduced and falls downward. At this time, if the reduction of the tin compound occurs above the glass ribbon GR, the reduced tin compound falls onto the glass ribbon GR. For this reason, there is a concern that the yield of manufactured float glass may be reduced.

In contrast, as described above, by lowering the concentration of the reducing gas (H ₂₎ above the glass ribbon GR, it can be suppressed tin compound is reduced. Therefore, according to this structure, it can suppress that the yield of the manufactured float glass falls.

  In addition, the float glass manufactured in the present embodiment is not limited to alkali-free glass, and the float glass manufacturing apparatus 1 and the float glass manufacturing method of the present embodiment can be applied to manufacturing various glasses. .

  In addition, each structure demonstrated above can be suitably combined in the range which is not mutually contradictory.

  DESCRIPTION OF SYMBOLS 1 ... Float glass manufacturing apparatus, 10 ... Float bath, 11a ... Bottom, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29 ... Top roll, 30 ... Heater, 40 ... Control apparatus, F1, F5, G1, G5 ... 1st section, F2, F4, G2, G4 ... 2nd section, Gm ... Molten glass, GR ... Glass ribbon, M ... Molten metal, Ma ... Surface, PL2 ... Dividing line, PL2a, PL2b, PL2c, PL2d ... Inside dividing line

Claims (7)

A float glass manufacturing apparatus comprising a float bath having a bottom in which molten metal is stored, continuously supplying molten glass on a surface of the molten metal to form a glass ribbon, and conveying the glass ribbon in a conveying direction. There,
The float bath is
A plurality of top rolls for supporting the glass ribbon by pressing an end in the width direction perpendicular to the conveying direction in the glass ribbon from above;
A plurality of heaters provided above the bottom;
A plurality of control devices for controlling the heater;
Have
The area where the heater is arranged when the float bath is viewed from above has a plurality of sections divided along the transport direction and the width direction,
The control device is provided for each of the sections, and collectively controls the plurality of heaters provided in the corresponding sections,
The dividing line between the sections adjacent to each other in the width direction is the region where the viscosity of the glass ribbon is 10 ^5.7 dPa · s or more and 10 ^7.5 dPa · s or less than the top roll. Including the inner dividing line located inside the width direction,
The float glass manufacturing apparatus, wherein a distance in the width direction between the inner dividing line and the top roll is 100 mm or more and 350 mm or less.   The inner division line is a division line between a first division provided at both ends in the width direction among the plurality of divisions and a second division adjacent to the first division in the width direction. The float glass manufacturing apparatus according to 1. In the first section, the output of the heater in a section included in a region where the viscosity of the glass ribbon is 10 ^5.7 dPa · s or more and 10 ^7.5 dPa · s or less is 30 kW / m ² or more. The float glass manufacturing apparatus according to claim 2. In the second section, the output of the heater in a section included in a region in which the viscosity of the glass ribbon is 10 ^5.7 dPa · s or more and 10 ^7.5 dPa · s or less is 20 kW / m ² or more. The float glass manufacturing apparatus according to claim 2 or 3.   The float glass manufacturing apparatus according to any one of claims 1 to 4, wherein the number of the sections arranged in the width direction is an odd number.   The float glass manufacturing apparatus according to any one of claims 1 to 5, wherein at least one pair of the sections adjacent to each other in the transport direction is shifted from each other in the width direction. On the surface of the molten metal stored in the float bath, a molten glass is continuously supplied to form a glass ribbon, and the glass ribbon is transported in the transport direction, and a float glass manufacturing method,
Using a plurality of top rolls, pressing the end of the glass ribbon in the width direction orthogonal to the transport direction from above to support the glass ribbon;
Heating the glass ribbon using a plurality of heaters;
Including
The area where the heater is arranged when the float bath is viewed from above has a plurality of sections divided along the transport direction and the width direction,
The plurality of heaters provided in the section are collectively controlled for each section,
The dividing line between the sections adjacent to each other in the width direction is the region where the viscosity of the glass ribbon is 10 ^5.7 dPa · s or more and 10 ^7.5 dPa · s or less than the top roll. Including the inner dividing line located inside the width direction,
The float glass manufacturing method, wherein a distance in the width direction between the inner dividing line and the top roll is 100 mm or more and 350 mm or less.

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