CN105884175B

CN105884175B - Method for manufacturing float plate glass and device for manufacturing float plate glass

Info

Publication number: CN105884175B
Application number: CN201610083858.8A
Authority: CN
Inventors: 泷口哲史; 镜味督博
Original assignee: Asahi Glass Co Ltd
Current assignee: AGC Inc
Priority date: 2015-02-13
Filing date: 2016-02-06
Publication date: 2020-05-22
Anticipated expiration: 2036-02-06
Also published as: KR20160100249A; JP2016147786A; CN105884175A

Abstract

The invention provides a method and an apparatus for manufacturing float plate glass, which can inhibit bubbles generated from molten metal existing at a seam of a bottom brick, thereby reducing bubble defects on the bottom surface of a glass ribbon. A method for producing float plate glass, wherein a molten glass 12 is obtained by charging a glass raw material 11 into a melting tank 10 and melting the glass, the molten glass 12 is continuously supplied onto the surface of a molten metal 13 contained in a bath 20 having bottom bricks 21A and a bottom shell 22A covering the bottom bricks 21A, and the molten glass 12 is caused to flow in a predetermined direction along the surface of the molten metal 13 to thereby form a glass ribbon 14 in a ribbon shape, wherein a fluid is jetted from a nozzle 32C toward an outer surface 22B of the bottom shell 22A to cool the outer surface 22B, and vibration transmitted from the nozzle 32C to the bottom bricks 21A is absorbed by a vibration absorbing member 38.

Description

Method for manufacturing float plate glass and device for manufacturing float plate glass

Technical Field

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

Background

The flat glass formed by the float process was produced by the following method. First, a glass raw material is put into a melting tank and melted to obtain molten glass. Next, the obtained molten glass is continuously supplied onto the surface of the molten metal contained in the bath. The supplied molten glass is float-formed into a glass ribbon in a ribbon-like shape while flowing from the upstream side to the downstream side along the surface of the molten metal. The glass ribbon is taken out from the outlet of the bath, then slowly cooled in a slow cooling furnace, and cut into glass plates of a predetermined size.

A method for producing a Flat glass formed by a float process is widely used for Flat glasses such as architectural Flat glasses, automotive Flat glasses, and Flat glasses for FPDs (Flat Panel displays) because of its high productivity and excellent flatness.

The bath is composed of a plurality of refractory bricks and an iron shell covering the outer surfaces of the refractory bricks, and the bath is filled with molten metal such as molten tin. Here, the refractory bricks constituting the hearth of the bath are referred to as bottom bricks, and the shell covering the outer surfaces of the bottom bricks is referred to as a bottom shell.

When the bath is configured as described above, when the molten metal reaches the bottom shell through the joint of the bottom bricks, the bottom shell may be deformed or broken by the heat of the molten metal.

In order to solve the above problem, in

patent documents

1 and 2, the bottom case is air-cooled by ejecting air from a plurality of nozzles to the outer surface of the bottom case. By air-cooling the bottom shell, the molten metal near the bottom shell of the joint of the bottom bricks can be solidified. Thus, the molten metal can be prevented from reaching the bottom case through the joint of the bottom bricks, and the deformation and damage of the bottom case can be prevented. When the molten metal is molten tin, the bottom shell may be cooled to a temperature lower than the melting point of tin (231.9 ℃).

Documents of the prior art

Patent document

Patent document 1: japanese laid-open patent publication No. 2012 and 36082

Patent document 2: japanese patent laid-open No. 2012 and 41262

Disclosure of Invention

Problems to be solved by the invention

When the outer surface of the bottom case is air-cooled to a temperature lower than the melting point of the molten metal as in

patent documents

1 and 2, a phase boundary between the molten metal (liquid phase) and the solid metal (solid phase) is formed at the joint of the bottom bricks. The position of the phase boundary is vertically varied according to the temperature variation of the molten metal and the temperature variation of the outer surface of the bottom case, and when the position of the phase boundary is downwardly varied, the solid metal forming the phase boundary is melted and transformed into the molten metal. At this time, bubbles are generated in the molten metal by the chemical reaction at the time of transition, and the bubbles rise from the molten metal in the bath and adhere to a surface (hereinafter, referred to as a bottom surface) of the glass ribbon flowing on the surface of the molten metal, which is in contact with the molten metal. The adhesion of the bubbles causes a concave bubble defect on the bottom surface of the glass ribbon, thereby deteriorating the flatness of the glass ribbon. A glass substrate for a liquid crystal display is produced by polishing the surface of a glass plate cut after float molding. The flatness of the glass ribbon during forming affects the amount of glass plate polishing and thus the productivity of glass substrates for liquid crystal displays.

Therefore, it is considered that the above-mentioned bubble defect can be reduced by suppressing the temperature fluctuation of the outer surface of the bottom case by controlling the air flow rate from the nozzle in

patent documents

1 and 2 while suppressing the temperature fluctuation of the molten metal. However, even if the temperature fluctuations of both are suppressed, the bubble defects cannot be reduced significantly.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a method for producing a float glass and an apparatus for producing a float glass, which can reduce bubble defects generated on the bottom surface of a glass ribbon by suppressing bubbles generated from a molten metal present at a joint of bottom bricks.

Means for solving the problems

The present inventors have conducted extensive studies to achieve the above object, and as a result, have found that the position of the phase boundary fluctuates due to the vibration transmitted to the bottom block.

As a vibration transmission system for transmitting vibration to the floor tile, there is a main structure system for transmitting vibration of an earthquake from a main body (a building in which a bath is installed) to the floor tile, but focusing on the fact that a bubble defect occurs in addition to the occurrence of the earthquake, it is considered that the cause of the bubble defect is not only the earthquake. Then, when a vibration transmission system other than an earthquake is studied, the following hypothesis is established focusing on the point that the nozzle for cooling the bottom case is directly supported by the bottom case or by the steel material for supporting the bottom case via the connecting member: the vibration of the nozzle is transmitted to the bottom brick via the connecting member and the bottom case, whereby the position of the phase boundary moves up and down. It has also been found that: the nozzle during operation vibrates by being transmitted with vibration from the fluid supplier and vibration of the fluid itself, and the vibration resonates depending on the position of the nozzle, and becomes larger than a single vibration (large amplitude and high frequency).

Thus, to confirm the above hypothesis, it was confirmed with the entity device that: when the vibration absorption unit is installed in the connecting member and absorbs the vibration transmitted from the nozzle to the bottom brick, the bubble defect is greatly reduced. Therefore, it can be confirmed that the position of the phase boundary moves up and down due to the vibration from the nozzle.

Accordingly, in order to achieve the above object, the present invention provides a method for manufacturing a float plate glass, in which a glass material is charged into a melting tank and melted to obtain a molten glass, the molten glass is continuously supplied onto a surface of a molten metal contained in a bath including bottom bricks and a bottom shell covering the bottom bricks, and the molten glass is made to flow along the surface of the molten metal from an upstream side to a downstream side of the bath, thereby forming a glass ribbon in a ribbon shape, wherein a fluid is ejected from a nozzle toward an outer surface of the bottom shell to cool the outer surface, and vibration transmitted from the nozzle to the bottom bricks is absorbed by a vibration absorbing means.

In order to achieve the above object, the present invention provides an apparatus for manufacturing a float plate glass, comprising: the melting tank includes a nozzle for ejecting a fluid onto an outer surface of the bottom casing to cool the outer surface, and a vibration absorbing unit for absorbing vibration transmitted from the nozzle to the bottom casing.

According to the aspect of the present invention, since the molten glass is formed into the glass ribbon while the vibration transmitted from the nozzles to the bottom bricks is absorbed by the vibration absorbing means, the bubble defects generated on the bottom surface of the glass ribbon can be greatly reduced.

According to an aspect of the present invention, it is preferable that: the nozzle is directly or indirectly supported by the bottom case via a connecting member, and a vibration absorbing unit is provided in the connecting member to absorb vibration of the nozzle.

According to an aspect of the present invention, it is preferable that: the nozzle is directly or indirectly supported by the bottom case via a connecting member, and the vibration absorbing unit is provided in the connecting member.

According to the present invention, since the vibration absorbing unit is provided in the connecting member supporting the nozzle to the bottom case, it is possible to absorb the vibration transmitted from the nozzle to the bottom brick.

Further, according to an aspect of the present invention, it is preferable that: the nozzle is connected to a fluid supply source via a fluid supply pipe, the fluid supply pipe is laid on a bottom plate of the bath tank via a vibration absorption unit, and vibration of the fluid supply pipe is absorbed by the vibration absorption unit.

According to an aspect of the present invention, it is preferable that: the nozzle is connected to a fluid supply source via a fluid supply pipe, and the fluid supply pipe is laid on the bottom plate of the bath tank through the vibration absorbing unit.

According to the present invention, by laying the fluid supply pipe on the bottom plate via the vibration absorbing means, it is possible to suppress transmission of vibration of the fluid supply pipe to the nozzle, and as a result, it is possible to suppress transmission of vibration from the nozzle to the connecting member. Thus, the vibration of the nozzle can be reliably absorbed by the vibration absorbing means provided in the connecting member.

Further, according to an embodiment of the present invention, the fluid is preferably air, a mixture of air and water, or water.

Further, according to an aspect of the present invention, it is preferable that: the vibration absorbing means is a vibration damping rubber, and a heat-resistant composition is blended with a base rubber of the vibration damping rubber.

Since the environment in which the nozzle is disposed is a high-temperature environment due to the radiant heat from the bottom case, when an appropriate vibration damping rubber is used as the vibration absorbing unit, it is preferable to blend a heat-resistant composition such as silicone rubber or carbon into the base rubber of the vibration damping rubber in order to stably and continuously exhibit the vibration absorbing function.

Effects of the invention

According to the method for manufacturing a float glass and the apparatus for manufacturing a float glass according to the present invention, since the molten glass is formed into the glass ribbon while the vibration transmitted from the nozzle to the bottom block is absorbed by the vibration absorbing means, the bubble defect generated on the bottom surface of the glass ribbon can be greatly reduced.

Drawings

Fig. 1 is a schematic side sectional view showing an embodiment of a method for manufacturing a float sheet glass of the present invention.

FIG. 2 is a sectional view taken along line A-A of FIG. 1, and is a sectional view of an apparatus for manufacturing float glass according to embodiment 1 of the vibration absorbing structure.

Fig. 3 is a sectional view showing an apparatus for manufacturing float glass according to embodiment 2 of the vibration absorbing structure.

Fig. 4 is a sectional view showing an apparatus for manufacturing float glass according to embodiment 3 of the vibration absorbing structure.

Reference numerals

10 … melting tank, 11 … glass raw material, 12 … molten glass, 13 … molten metal, 14 … glass ribbon, 20 … bath, 21 … brick, 21a … bottom brick, 22 … shell, 22a … bottom shell, outer surface of 22B … bottom shell, 22C … side shell, 30 … fluid supply device, 31 … fluid supply machine, 32 … supply pipe, 32a … conduit, 32B … nozzle unit, 32C … nozzle, 32D … jet port, 32E … straight pipe, 34 … rod, 36 … rod, 38 … vibration absorbing member, 40 … connecting member, 42 … connecting member, 44 … steel, 46 … vibration absorbing member, 48 … bottom plate, 50 iron plate 50 … connecting member, 52 … connecting member, 54 …, 56 steel 56 … H, 58 … connecting member, 100A, 100B … float glass manufacturing device

Detailed Description

Hereinafter, preferred embodiments of a method for manufacturing a float glass and an apparatus for manufacturing a float glass according to the present invention will be described in detail with reference to the accompanying drawings.

Fig. 1 is a sectional view showing an embodiment of a float glass manufacturing apparatus 100 according to the present invention. Fig. 2 is a sectional view of the apparatus 100 for manufacturing float glass along line a-a of fig. 1, showing the vibration absorbing structure of embodiment 1. In fig. 1 and 2, the shapes of the constituent members of the apparatus 100 for producing float glass and the glass ribbon 14 are shown in an enlarged scale for ease of explanation of the apparatus configuration of the apparatus 100 for producing float glass.

The float plate glass is manufactured by the following method using the float plate glass manufacturing apparatus 100 shown in fig. 1 and 2. First, glass raw material 11 shown in fig. 1 is put into melting tank 10 and melted to obtain molten glass 12. Next, the molten glass 12 is continuously supplied onto the surface of the molten metal 13 contained in the bath 20. Subsequently, the supplied molten glass 12 is caused to flow from the upstream side to the downstream side (the direction from the left side to the right side in fig. 1) along the surface of the molten metal 13, and float-formed into a glass ribbon 14 in a ribbon shape. The glass ribbon 14 is taken out from the outlet of the bath 20 by a lift roller (not shown), and then is gradually cooled in a slow cooling furnace (not shown), and then cut into glass plates having a predetermined size. The molten metal 13 is molten tin.

In fig. 1, molten glass 12 obtained from a melting tank 10 is directly supplied to a bath 20, but the present invention is not limited thereto. The molten glass 12 obtained from the melting tank 10 may be supplied to the bath 20 through a defoaming device for defoaming bubbles contained in the molten glass 12, a stirring device for stirring and homogenizing the molten glass 12, and the like.

The bath 20 includes a plurality of bricks 21 and a shell 22 covering the outer surfaces of the bricks 21, and the bath 20 is filled with the molten metal 13. In the present specification, the bricks constituting the hearth of the vessel 20 are referred to as bottom bricks 21A, and the shell covering the outer surface of the bottom bricks 21A is referred to as a bottom shell 22A.

The material of the bricks 21 may be a material having low reactivity or non-reactivity with the molten metal 13 or a material having high temperature resistance, and examples thereof include alumina, sillimanite (sillimanite), clay, and the like.

The material of the bottom case 22A is not particularly limited, and is made of a metal material such as iron or stainless steel.

A fluid supply device 30 for cooling the bottom case 22A is disposed below the bottom case 22A.

The fluid supply device 30 is constituted by a fluid supply machine (fluid supply source) 31 and a supply pipe 32. The fluid supplier 31 is a device that supplies fluid for cooling the outer surface 22B of the bottom case 22A. The fluid supplied from the fluid supply device 31 is ejected to the outer surface 22B of the bottom case 22A via a supply pipe 32 described later.

The fluid used is not particularly limited as long as it can cool the outer surface 22B of the bottom case 22A, and may be air, water, or a mixture of air and water. The fluid is preferably air in view of the ease of application to a conventional float glass manufacturing apparatus. When the fluid is air, the fluid supplier 31 is a blower.

The supply pipe 32 is composed of a conduit (fluid supply pipe) 32A as a main pipe and a plurality of nozzle units 32B. The conduit 32A is disposed along the longitudinal direction of the bath 20 (the flow direction of the glass ribbon 14), and one end thereof is connected to the fluid supplier 31. The nozzle unit 32B branches from the duct 32A in the longitudinal direction of the bath 20, and further branches into 4 nozzles 32C in the width direction of the bath 20 as shown in fig. 2. The ejection port 32D of the nozzle 32C is disposed opposite to the outer surface 22B of the bottom case 22A. The fluid supplied from the fluid supplier 31 passes through the conduit 32A to be supplied to the nozzle unit 32B, and is then ejected from the ejection ports 32D of the respective nozzles 32C toward the outer surface 22B of the bottom case 22A. Thereby, the outer surface 22B of the bottom case 22A is cooled.

The configuration of the supply pipe 32 is not limited to the above configuration. That is, the nozzle units 32B arranged along the longitudinal direction of the bath 20 may be arranged without being distributed over the entire range of the bath 20 in the longitudinal direction. For example, the nozzle unit 32B may be disposed to be offset toward the upstream side (left side in fig. 1) of the bath 20. Since many bubbles generated from the molten metal existing at the joints of the bottom bricks 21A are generated from the molten metal on the upstream side of the bath 20, the generation of bubbles can be effectively suppressed by disposing the nozzle units 32B to be offset to the upstream side.

The number of nozzle units 32B is not particularly limited as long as the generation of bubbles can be suppressed, and may be 1 or more. The branching interval of the nozzle units 32B in the longitudinal direction of the bath 20 is not particularly limited, and may be a constant interval or a non-constant interval.

Since the plurality of (4 in fig. 2) nozzles 32C branched in the width direction of the bath 20 are branched in a shape with their ends widened, the temperature distribution in the width direction of the outer surface 22B of the bottom shell 22A can be made uniform.

The number of nozzles 32C in the width direction of the bath 20 is not particularly limited as long as the temperature distribution in the width direction of the bath 20 can be made uniform. The branch interval of the nozzles 32C in the width direction of the bath 20 is not particularly limited, and may be a constant interval or a non-constant interval.

As shown in fig. 1, the nozzle units 32B arranged in the longitudinal direction of the bath 20 are connected to each other by the metal rod-shaped body 34, so that the rigidity of the nozzle units 32B in the longitudinal direction of the bath 20 is increased. The connecting position of the rod-like member 34 is preferably fixed to the straight tube 32E before branching into the nozzle 32C by welding or the like as shown in fig. 2.

As shown in fig. 2, the nozzles 32C arranged in the width direction of the bath 20 are connected to each other by the metal rod-like body 36, so that the rigidity of the nozzles 32C in the width direction of the bath 20 is increased. The rod-like body 36 is also preferably fixed by welding or the like.

In the embodiment, only the bottom case 22A is cooled, but the present invention is not limited thereto. Supply pipes for cooling the brick-covered side casing 22C of the side wall of the bath 20 may be provided. By also cooling side shell 22C, bubble defects can be further effectively reduced.

The apparatus 100 for manufacturing float plate glass according to the embodiment includes a vibration absorbing member (vibration absorbing means) 38 such as vibration-proof rubber as shown in fig. 2 in order to prevent vibration from being transmitted from the nozzle 32C to the bottom brick 21A via the bottom case 22A, that is, in order to reduce bubble defects.

That is, the nozzle 32C is directly supported by the bottom case 22A via the metal connecting member 40, or indirectly supported by the bottom case 22A via the steel 44 that supports the bottom case 22A via the metal connecting member 42. The vibration absorbing member 38 is provided in these connecting

members

40, 42. Thus, although the vibration of the nozzle 32C is transmitted to the connecting

members

40 and 42, the vibration is absorbed (damped) by the vibration absorbing member 38, and therefore, the vibration is not transmitted to the bottom brick 21A.

Therefore, in the float glass manufacturing apparatus 100 according to the embodiment, the molten glass 12 is formed into the glass ribbon 14 while the vibration transmitted from the nozzles 32C to the bottom bricks 21A is absorbed by the vibration absorbing member 38, and therefore, the bubble defects generated on the bottom surface of the glass ribbon 14 can be reduced.

As shown in fig. 1, the conduit 32A and the fluid supply device 31 are preferably laid on a bottom plate 48 of the bath tub 20 via a plurality of vibration absorbing members (vibration absorbing means) 46 such as vibration-free rubber. Since the vibration of the conduit 32A and the fluid supplier 31 can be absorbed by the vibration absorbing member 46, the vibration transmitted from the nozzle 32C to the connecting

members

40, 42 can be reduced as a result. Thus, the vibration of the nozzle 32C can be reliably absorbed by the vibration absorbing member 38 provided in the connecting

members

40, 42.

Fig. 3 is a sectional view showing a float glass manufacturing apparatus 100A of embodiment 2 of the vibration absorbing structure. According to fig. 3, the conduit 32A is directly supported by the bottom case 22A via the connecting member 50, or the conduit 32A is supported by the steel 44 via the connecting member 52, and the vibration absorbing member 38 is provided in the connecting

members

50, 52.

According to the vibration absorbing structure of fig. 3, the vibration of the conduit 32A can be absorbed by the vibration absorbing member 38, and therefore, as a result, the vibration transmitted from the conduit 32A to the connecting

members

50, 52 can be reduced. Therefore, bubble defects generated at the bottom surface of the glass ribbon 14 can be reduced.

Fig. 4 is a sectional view showing a manufacturing apparatus 100B for float glass according to embodiment 3 of the vibration absorbing structure. According to fig. 4, the bath tub 20 is provided on the bottom plate 48 by a band-shaped iron plate 54 laid on the bottom of the bath tub 20 and a plurality of H-shaped steels 56 (see fig. 1). The iron plates 54 are laid at predetermined intervals in a direction orthogonal to the longitudinal direction of the bath tub 20, and the H-shaped steels 56 are laid along the longitudinal direction of the bath tub 20 so as to support the lower surface of the iron plates 54.

Further, as for the nozzles 32C, each nozzle 32C is supported to the H-shaped steel 56 via a connecting member 58, and a vibration absorbing member 38 is provided in each connecting member 58.

Even in the vibration absorbing structure of fig. 4, since the vibration of the nozzles 32C can be absorbed by the vibration absorbing member 38, the bubble defect generated on the bottom surface of the glass ribbon 14 can be reduced.

When the vibration damping rubber is used as the vibration absorbing member 38, it is preferable to blend a heat-resistant composition in advance with the base rubber of the vibration damping rubber.

Since the environment in which the nozzle 32C is disposed is a high-temperature environment due to the radiant heat from the bottom case 22A, when an appropriate vibration damping rubber is used as the vibration absorbing member 38, it is preferable to blend a heat-resistant composition such as silicone rubber or carbon into the base rubber of the vibration damping rubber in order to stably and continuously exhibit the vibration absorbing function.

In addition, a fluid damper provided with a cylinder and a piston may be used as the vibration absorbing member 38. When the fluid damper is used, it is preferable that: the direction in which the vibration is damped is confirmed in advance, and the fluid damper is attached to the cylinder so as to be relatively extended and contracted with respect to the piston in this direction.

The present application is based on japanese patent application 2015-025924, filed on 13/2/2015, the contents of which are incorporated herein by reference.

Industrial applicability

Since the glass sheet obtained by the method and apparatus for producing float glass of the present invention has a small number of bubble defects on the bottom surface, the amount of polishing of the bottom surface can be reduced, thereby improving the productivity of the glass sheet. The obtained glass plate is useful as a glass substrate for a display such as a liquid crystal display.

Claims

1. A method for producing float plate glass, comprising charging a glass raw material into a melting tank, melting the glass raw material to obtain molten glass,

continuously supplying the molten glass onto a surface of molten metal contained in a bath including bottom bricks and a bottom shell covering the bottom bricks,

forming the molten glass into a glass ribbon in a shape of a strip plate by flowing the molten glass along a surface of the molten metal from an upstream side to a downstream side of the bath,

spraying a fluid from a nozzle to an outer surface of the bottom case to cool the outer surface, and absorbing vibration transferred from the nozzle to the bottom bricks by a vibration absorbing unit, and

the nozzle is directly or indirectly supported to the bottom case via a connection member, and a vibration absorption unit is provided in the connection member, by which vibration of the nozzle is absorbed.

2. A method for producing float plate glass, comprising charging a glass raw material into a melting tank, melting the glass raw material to obtain molten glass,

the nozzle is connected to a fluid supply source via a fluid supply pipe, the fluid supply pipe is laid on a bottom plate of the bath through a vibration absorption unit, and vibration of the fluid supply pipe is absorbed by the vibration absorption unit.

3. The method of manufacturing a float plate glass according to claim 1 or 2, wherein the fluid is air, a mixture of air and water, or water.

4. A float glass manufacturing apparatus includes: a melting tank for melting glass raw materials to obtain molten glass, and a bath tank for containing molten metal to which the molten glass is continuously supplied on the surface and having a bottom brick and a bottom shell for covering the bottom brick,

it is characterized in that the preparation method is characterized in that,

has a nozzle for spraying fluid to the outer surface of the bottom case to cool the outer surface, and a vibration absorption unit for absorbing vibration transmitted from the nozzle to the bottom bricks, and

the nozzle is directly or indirectly supported to the bottom case via a connection member in which the vibration absorbing unit is disposed.

5. A float glass manufacturing apparatus includes: a melting tank for melting glass raw materials to obtain molten glass, and a bath tank for containing molten metal to which the molten glass is continuously supplied on the surface and having a bottom brick and a bottom shell for covering the bottom brick,

it is characterized in that the preparation method is characterized in that,

the nozzle is connected to a fluid supply source via a fluid supply pipe, and the fluid supply pipe is laid on the bottom plate of the bath tank through the vibration absorption unit.

6. The manufacturing apparatus of float plate glass according to claim 4 or 5,

the vibration absorbing unit is a vibration-proof rubber, and a heat-resistant composition is blended with a base rubber of the vibration-proof rubber.

7. The manufacturing apparatus of float plate glass according to claim 4 or 5,

the fluid supplied from the fluid supply source is air, a mixture of air and water, or water.