KR101494517B1 - Method for manufacturing glass substrate, apparatus for manufacturing glass substrate and stirring apparatus - Google Patents

Abstract

The method for producing a glass substrate, the apparatus for producing a glass substrate and the stirring apparatus according to the present invention can suppress the deformation and breakage of the stirrer used for stirring the molten glass and homogenously stir the molten glass. The molten glass G is agitated by an agitator 102 disposed inside the agitating tank 101 while being guided in the inside of the agitating tank 101 from above to below or from above to below. The stirrer 102 is fixed to the outer circumferential surface of the rotary shaft 105 by being fitted to the rotary shaft 105 and is disposed at a plurality of stages from the uppermost stage to the lowermost stage along the rotary shaft 105 And stirring wings 106a to 106e. The stirrer 102 is formed of reinforced platinum at least in a portion where the stirring vanes 106a to 106e are fitted to the rotating shaft 105 and in the vicinity thereof.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method for manufacturing a glass substrate,

The present invention relates to a production method of a glass substrate, an apparatus for producing a glass substrate and a stirring apparatus.

In mass production of glass products such as glass substrates, glass raw materials are heated to produce molten glass, and the resulting molten glass is molded to produce glass products. Inhomogeneous molten glass is the cause of the malformation occurring in the glass product. In the use of optical components such as lenses and substrates for liquid crystal displays (LCD), it is required to be strictly excluded from glass products. Particularly, in a glass substrate for a flat panel display (FPD) represented by an LCD substrate, it is necessary to suppress the fringing on the entire surface of the substrate to a very low level in order to prevent unevenness of cell gaps. It is important to homogenously stir the molten glass in the manufacturing process of the glass product in order to suppress the occurrence of the molten glass.

Generally, the stirrer for stirring the molten glass includes a stirrer and a stirrer disposed inside the stirrer. The stirrer has a rotary shaft and a stirring blade attached to the outer peripheral surface of the rotary shaft by welding. The molten glass is supplied to the stirring tank, and the stirrer is rotated, whereby the molten glass is stirred and homogenized. The inner wall of the stirring tank and the stirrer in contact with the molten glass at a high temperature are formed of platinum, platinum alloy or reinforced platinum from the viewpoints of heat resistance and oxidation resistance. The platinum alloy is, for example, a platinum-rhodium alloy, and has a higher melting point and strength than platinum. Reinforced platinum is a platinum material in which an oxide such as zirconia is dispersed in platinum or a platinum alloy. The reinforced platinum has a layered platinum-grain boundary structure, and has higher creep strength and tensile strength at high temperature than platinum or platinum alloy. Therefore, as disclosed in Patent Document 1 (Japanese Patent Application Laid-Open No. 2005-511462), the inner wall of the stirring tank and the stirrer are preferably formed of reinforced platinum.

Japanese Patent Application Publication No. 2005-511462

However, when the reinforced platinum is heated and melted at a temperature higher than the melting point, the layered platinum-grain boundary structure is destroyed, and the strength is lowered to the same level as that of ordinary platinum or platinum alloy. Therefore, when the stirrer used in the stirring apparatus for molten glass is formed by welding of the reinforced platinum member, the creep strength and tensile strength of the welded portion are lower than those at other portions. Further, while the stirrer is stirring the molten glass, since the rotary shaft of the stirrer supports the stress applied to the stirring wing, it is particularly susceptible to a large load from the molten glass having a high viscosity. Further, the rotating shaft of the stirrer is easily subjected to a load due to its own weight of the stirring wing itself. These loads also occur in the components of the stirrer around the rotating shaft. Therefore, when the stirrer is attached to the rotating shaft by welding or when the stirrer is formed by welding, the stirrer is easily deformed or broken due to a decrease in the strength of the welded portion, so that the molten glass is homogeneously It is difficult to stir.

An object of the present invention is to provide a production method of a glass substrate, an apparatus for producing a glass substrate and a stirring apparatus which can suppress the deformation and breakage of the stirrer used for stirring the molten glass and can homogeneously stir the molten glass.

A manufacturing method of a glass substrate according to the present invention comprises a melting step of melting a glass material to obtain a molten glass and a stirring step of stirring the molten glass obtained in the melting step. In the stirring process, the molten glass is stirred by an agitator disposed inside the stirring tank while being led from the upper side downward or from the lower side into the stirring tank. The stirrer has a rotating shaft disposed along the vertical direction, and a stirring blade fixed to the outer peripheral surface of the rotating shaft by being fitted to the rotating shaft and arranged in plural stages from the uppermost stage to the lowermost stage along the rotating shaft. The stirrer is formed of reinforced platinum at least at a portion where the stirring wing is fitted to the rotating shaft and in the vicinity thereof.

In this method of manufacturing a glass substrate, the stirrer used in the stirring step is formed of reinforced platinum, and is also assembled by fitting a stirring blade to the rotating shaft. The reinforced platinum has a property of lowering in strength to the same extent as that of ordinary platinum or platinum alloy when it is heated and melted at a temperature higher than its melting point. Therefore, by attaching the stirring blade to the rotation shaft by fitting, the strength of the connecting portion of the rotation shaft and the stirring blade can be suppressed from being lowered as compared with the case where the stirring blade is attached to the rotation shaft by welding. Therefore, in this method of producing a glass substrate, deformation and breakage of the stirrer used for stirring the molten glass are suppressed, so that the molten glass can be homogeneously stirred.

In the method of manufacturing a glass substrate according to the present invention, it is preferable that the rotary shaft has a fitting hole formed on the outer circumferential surface thereof and in which a part of the stirring blade is fitted. It is preferable that the stirring blade has a fitting protrusion fitted to the fitting hole of the rotating shaft and is fixed to the outer circumferential face of the rotating shaft by inserting the fitting protrusion into the fitting hole of the rotating shaft.

In the method of manufacturing a glass substrate according to the present invention, in the case where the molten glass agitated by the stirrer in the stirring step is a glass having a viscosity of 10 ^2.5 dPa s at a temperature of 1450 캜 or higher, Lt; / RTI >

In the method of manufacturing a glass substrate according to the present invention, it is preferable that the content of the alkali metal oxide in the glass substrate is 0% by mass to 2% by mass.

In the method of manufacturing a glass substrate according to the present invention, it is preferable that the glass substrate is any one of a glass substrate for a liquid crystal display and a glass substrate for an organic EL display.

Further, in the method of manufacturing a glass substrate according to the present invention, it is preferable that the glass substrate is any one of a glass substrate for a low-temperature polycrystalline Si TFT loaded display and a glass substrate for an oxide semiconductor mounted display.

In the method for producing a glass substrate according to the present invention, the viscosity of the molten glass in the stirring step is preferably 450 dPa 占 퐏 to 2500 dPa 占 퐏.

In the method of manufacturing a glass substrate according to the present invention, it is preferable that the stirring vane has a support plate perpendicular to the center line of the rotation shaft and an assisting plate disposed on the main surface above and below the support plate. Further, in the stirring step, the stirrer rotates about the center line of the rotating shaft, so that the auxiliary plate generates the flow of the rotating shaft in the radial direction in the molten glass, and the stirring plate It is preferable that the assisting plate positioned between the glass plate and the glass plate causes a flow in the same direction in the molten glass.

In the production method of this glass substrate, the molten glass in the stirring tank is scratched on the rotating shaft side or extruded on the inner wall side of the stirring tank by the shaft rotation of the stirrer. That is, the molten glass is stirred and moved in the radial direction of the rotating shaft while being guided in the stirring tank from above to below or from below. In this method of producing a glass substrate, molten glass can be homogeneously stirred without using a stirrer having a complicated structure.

Further, in the method of manufacturing a glass substrate according to the present invention, in the stirring step, the agitator is rotated around the center line of the rotating shaft, whereby the auxiliary plate disposed on the upper main surface of the supporting plate and the supporting plate One auxiliary plate generates a flow toward the rotating shaft from the inner wall of the stirring tank to the molten glass and the other auxiliary plate causes the molten glass to flow from the rotating shaft to the inner wall of the stirring tank desirable.

In the method of manufacturing a glass substrate according to the present invention, the stirring step may include a first stirring step of stirring the molten glass in the first stirring tank while guiding the molten glass upward from below, and a second stirring step And a second stirring step in which the molten glass stirred in the stirring step is stirred while being guided downward from above. The first stirring vessel includes a first chamber, a first stirrer for stirring the molten glass in the first chamber, and a first discharge pipe through which the molten glass can be discharged from the bottom of the first chamber. The second stirring tank includes a second chamber, a second stirrer for stirring the molten glass in the second chamber, and a second discharge pipe for discharging the molten glass from the surface of the molten glass in the second chamber. The upper side of the first stirring tank is connected to the upper side of the second stirring tank by a connecting pipe. The molten glass is transferred from the first stirring tank to the second stirring tank through the connecting pipe.

Further, an apparatus for manufacturing a glass substrate according to the present invention includes a melting unit for melting glass raw material to obtain molten glass, and a stirring unit for stirring the molten glass obtained in the molten glass unit. The stirring section has a stirring vessel and a stirrer disposed inside the stirring vessel. The stirrer stirs the molten glass guided from the upper side downward or from the lower side to the inside of the stirring tank. The stirrer has a rotating shaft disposed along the vertical direction, and a stirring blade fixed to the outer peripheral surface of the rotating shaft by being fitted to the rotating shaft and arranged in plural stages from the uppermost stage to the lowermost stage along the rotating shaft. The stirrer is formed of reinforced platinum at least at a portion where the stirring wing is fitted to the rotating shaft and in the vicinity thereof.

Further, the stirring apparatus according to the present invention is a stirring apparatus for stirring molten glass, which comprises a stirring tank and a stirrer disposed inside the stirring tank. The stirrer stirs the molten glass guided from the upper side downward or from the lower side to the inside of the stirring tank. The stirrer has a rotating shaft disposed along the vertical direction, and a stirring blade fixed to the outer peripheral surface of the rotating shaft by being fitted to the rotating shaft and arranged in plural stages from the uppermost stage to the lowermost stage along the rotating shaft. The stirrer is formed of reinforced platinum at least at a portion where the stirring wing is fitted to the rotating shaft and in the vicinity thereof.

A method of manufacturing a glass substrate according to the present invention includes a melting step of melting a glass material to obtain a molten glass, a stirring step of stirring the molten glass obtained in the melting step, a stirring step of stirring the glass substrate from the molten glass stirred in the stirring step And a molding step for molding. In the stirring process, the molten glass is stirred by an agitator disposed inside the stirring tank while being led from the upper side downward or from the lower side into the stirring tank. The stirrer has a rotating shaft disposed along the vertical direction, and a stirring blade fixed to the outer peripheral surface of the rotating shaft by being fitted to the rotating shaft and arranged in plural stages from the uppermost stage to the lowermost stage along the rotating shaft. The stirrer is formed of reinforced platinum at least at a portion where the stirring wing is fitted to the rotating shaft and in the vicinity thereof.

The apparatus for manufacturing a glass substrate according to the present invention comprises a melting unit for melting a glass material to obtain molten glass, an agitating unit for agitating the molten glass obtained in the molten glass, a glass substrate for agitating the molten glass, And a molding part for molding. The stirring section has a stirring vessel and a stirrer disposed inside the stirring vessel. The stirrer stirs the molten glass guided from the upper side downward or from the lower side to the inside of the stirring tank. The stirrer has a rotating shaft disposed along the vertical direction, and a stirring blade fixed to the outer peripheral surface of the rotating shaft by being fitted to the rotating shaft and arranged in plural stages from the uppermost stage to the lowermost stage along the rotating shaft. The stirrer is formed of reinforced platinum at least at a portion where the stirring wing is fitted to the rotating shaft and in the vicinity thereof.

The method for producing a glass substrate, the apparatus for producing a glass substrate and the stirring apparatus according to the present invention can suppress the deformation and breakage of the stirrer used for stirring the molten glass and homogenously stir the molten glass.

1 is a schematic diagram showing an example of a configuration of a glass manufacturing apparatus according to a first embodiment;
2 is a side view of the stirring apparatus according to the first embodiment;
3 is a perspective view of a stirring blade of an agitator according to the first embodiment;
4 is a plan view of a stirring blade of an agitator according to the first embodiment;
5 is a perspective view of a stirring blade of an agitator according to the first embodiment.
6 is a plan view of a stirring blade of an agitator according to the first embodiment;
7 is a view showing the arrangement of two stirring blades of the stirrer according to the first embodiment;
8 is a view showing an arrangement of bearings of a stirring vane according to the first embodiment;
9 is a side view of a bearing of a stirring vane according to the first embodiment;
10 is a top view of a bearing of a stirring vane according to the first embodiment;
11 is a top view showing a state before the wedge of the stirring wing according to the first embodiment is fitted to the rotation shaft.
12 is a top view showing a state after the wedge of the stirring blade according to the first embodiment is fitted to the rotation shaft.
13 is a view showing the flow of molten glass in the stirring apparatus according to the first embodiment;
14 is a perspective view of an agitator according to Modification B of the first embodiment;
Fig. 15 is a top view of a stirring blade of an agitator according to Modification C of the first embodiment; Fig.
16 is a schematic diagram showing an example of the configuration of a glass manufacturing apparatus according to the second embodiment;
17 is a top view of the upper side support plate of the stirring blade of the stirrer according to the third embodiment.
18 is a longitudinal sectional view of an upper side support plate of a stirring blade of an agitator according to the third embodiment.
19 is a side view of the upper side support plate of the stirring wing of the stirrer according to the third embodiment.
Fig. 20 is a side view of the outer end of the upper side assisting plate of the stirring wing of the stirrer according to the third embodiment. Fig.
21 is a cross-sectional view of an upper side assisting plate of a stirring wing of a stirrer according to the third embodiment;

≪ First Embodiment >

(1) Overall configuration of the glass manufacturing apparatus

A first embodiment of a method of manufacturing a glass substrate, an apparatus for producing a glass substrate and a stirring apparatus according to the present invention will be described with reference to the drawings. 1 is a schematic diagram of a glass manufacturing apparatus 200 according to the present embodiment. The glass manufacturing apparatus 200 includes a melting tank 40, a blue sign 41, a stirring device 100, and a molding device 42. The melting tank 40 and the blue sign 41 are connected by a conduit 43a. The blue sign 41 and the stirring device 100 are connected by a conduit 43b. The stirring device 100 and the molding device 42 are connected by a conduit 43c. The molten glass G generated in the melting tank 40 flows into the blue sign 41 through the conduit 43a. The molten glass G refined in the blue oven 41 passes through the conduit 43b and flows into the stirring apparatus 100. [ The molten glass G stirred in the stirring apparatus 100 passes through the conduit 43c and flows into the molding apparatus 42. [ In the molding apparatus 42, the glass ribbon 44 is formed from the molten glass G by a down-draw method.

Although not shown, the melting tank 40 is provided with heating means such as a burner. In the melting tank 40, the glass raw material is dissolved by the heating means, and molten glass G is produced. The glass raw material is prepared so as to substantially obtain a glass having a desired composition. As an example of the composition of the glass, non-alkali glass and non-alkali glass are, SiO _2: 57 wt% ~65 wt%, Al ₂ O _3: 15 wt% ~19 wt%, B ₂ O _3: 8% by mass of ~13 mass%, MgO: 1% by mass to 3% by mass, CaO: 4 mass% to 7 mass%, SrO: 1 mass% to 4 mass%, BaO: 0% by mass to 2% by weight, Na ₂ O: 0 wt% to 1 mass%, K ₂ O: 0 wt% to 1 mass%, As ₂ O _3: 0 wt% to 1 wt%, Sb ₂ O _3: 0 wt% to 1 mass%, SnO _2: 0% by weight - 1 mass%, Fe ₂ O ₃ : 0 mass% to 1 mass%, and ZrO ₂ : 0 mass% to 1 mass%. Here, " substantially " means that in the range of less than 0.1% by mass, the presence of other trace components is allowed. With respect to the glass having the above composition, the respective content ratios of Fe ₂ O ₃ , As ₂ O ₃ , Sb ₂ O ₃ and SnO ₂ are set such that the components of Fe, As, Sb or Sn having a plurality of valences are Fe ₂ O ₃ , As ₂ O ₃ , Sb ₂ O ₃ or SnO ₂ .

The glass raw material thus prepared is put into the dissolution tank 40. In the melting tank 40, the glass raw material is dissolved at a temperature according to the composition or the like. Thus, in the melting tank 40, for example, a high-temperature molten glass G of 1500 ° C to 1600 ° C is obtained.

The molten glass G obtained in the melting tank 40 flows from the melting tank 40 through the conduit 43a and into the blue bulb 41. The blue sign 41 is provided with a heating means, which is not shown, like the melting vessel 40. In the blue sign 41, the molten glass G is refreshed by heating the molten glass G further. In the blue sign 41, the temperature of the molten glass G is preferably raised to 1600 캜 to 1800 캜, more preferably to 1630 캜 to 1750 캜, and still more preferably to 1650 캜 to 1750 캜.

The molten glass G refined in the blue oven 41 passes through the conduit 43b from the blue oven 41 and flows into the stirring apparatus 100. [ The molten glass G is cooled when it passes through the conduit 43b so that the molten glass G at a temperature lower than the molten glass G of the blue oven 41 is stirred in the stirring apparatus 100. [ With respect to the glass having the above composition, in the stirring apparatus 100, the temperature of the molten glass G is set within the range of 1400 ° C. to 1550 ° C. and the viscosity of the molten glass G is set within the range of 2500 dPa · s to 450 dPa · s So that the molten glass G is agitated. The molten glass G is homogenized by stirring in the stirring apparatus 100.

The molten glass G stirred and homogenized in the stirring apparatus 100 flows from the stirring apparatus 100 through the conduit 43c and into the molding apparatus 42. [ When the molten glass G passes through the conduit 43c, the molten glass G is cooled to a temperature suitable for molding in the molding apparatus 42, for example, to 1200 deg. In the molding apparatus 42, the glass ribbon 44 is formed from the molten glass G by the down-draw method. Concretely, the molten glass G flowing over from the upper portion of the molding machine 42 flows downward along the side wall of the molding machine 42, whereby the glass ribbon 44 is continuously formed from the lower end of the molding machine 42 do. The glass ribbon 44 is gradually cooled downward, and finally cut into a glass substrate of a desired size.

(2) Constitution of stirring device

(2-1) Overall configuration of stirring device

2 is a side view of the stirring apparatus 100. Fig. The stirring apparatus 100 is provided with a cylindrical stirring vessel 101 and a stirrer 102 disposed inside the stirring vessel 101. The stirring vessel The stirring tank 101 has an upstream conduit 103 attached to the upper side surface and a downstream conduit 104 attached to the lower side surface. The upstream side conduit 103 is the conduit 43b and the downstream conduit 104 is the conduit 43c. The molten glass G flows into the stirring tank 101 from the upstream side conduit 103 in the horizontal direction and is stirred by the stirrer 102 while being guided downward from above in the stirring tank 101, In the horizontal direction from the inside of the downstream conduit 104. [

The stirrer 102 is formed of reinforced platinum. Reinforced platinum is a material obtained by dispersing an oxide such as zirconia in platinum or a platinum alloy and rolling it. The reinforced platinum has a layered platinum-grain boundary structure, and has higher creep strength and tensile strength at high temperature than platinum or platinum alloy. Therefore, the reinforced platinum is a suitable material for the stirrer 102 to which the high-temperature molten glass G contacts.

The stirrer 102 has a cylindrical rotary shaft 105 disposed along the vertical direction and five stirring blades 106a, 106b, 106c, 106d, and 106e connected to the outer peripheral surface of the rotary shaft 105. [ The stirring vanes 106a, 106b, 106c, 106d, and 106e are arranged at regular intervals in this order from above to below along the rotating shaft 105. [ The rotary shaft 105 rotates about the center line L connecting the center of the upper surface of the cylindrical shape and the center of the lower surface. That is, the rotary shaft 105 has a configuration in which the five stages of stirring vanes 106a to 106e are arranged along the center line L thereof. The rotary shaft 105 is a tubular member whose interior is hollow.

(2-2) Configuration of stirring wing

Next, the configuration of the stirring vanes 106a to 106e will be described. In the present embodiment, the stirring vanes 106a, 106c, and 106e have the same shape and the stirring vanes 106b and 106d have the same shape. 3 and 4 are a perspective view and a plan view of the stirring vanes 106a, 106c and 106e. 5 and 6 are a perspective view and a plan view of the stirring vanes 106b and 106d. 3 and 5 show stirring vanes 106a to 106e attached to the outer circumferential surface of the rotary shaft 105. As shown in Fig.

Each of the stirring vanes 106a to 106e is arranged so as to extend from the rotating shaft 105 toward the inner wall of the stirring tank 101. [ Each of the stirring vanes 106a to 106e includes three support plates 108 orthogonal to the center line L of the rotary shaft 105 and one upper auxiliary plate 119a disposed on the upper main surface of each support plate 108, And one lower auxiliary plate 119b disposed on the lower main surface of each of the support plates 108. As shown in Fig. Hereinafter, the upper side support plate 119a and the lower side support plate 119b are collectively referred to as an assisting plate 109. [ The auxiliary plate 109 of the stirring vanes 106a to 106e is formed by bending. Specifically, one reinforcing platinum plate is bent to form stirring vanes 106a to 106e in which the supporting plate 108 and the supporting plate 109 are integrated.

The three support plates 108 of the respective stirring vanes 106a to 106e are arranged at positions corresponding to the position of the center line L of the rotation shaft 105 in the case where the stirring vanes 106a to 106e are viewed along the center line L of the rotation shaft 105 And are arranged at positions symmetrical three times. The normal line of the main surface of each support plate 108 is parallel to the center line L of the rotation shaft 105. That is, the support plate 108 is arranged horizontally. The three support plates 108 of the stirring vanes 106a to 106e are connected to each other by the connection portion 110 around the rotation shaft 105. [ That is, the three support plates 108 of the respective stirring vanes 106a to 106e constitute substantially one component.

Each of the stirring vanes 106a to 106e is configured such that when the support plate 108 of the stirring vanes 106a to 106e disposed at two adjacent stages is projected on the bottom surface of the stirring tank 101, The space between the support plate 108 and the support plate 108 is minimized so that the interval between the support plate 108 and the support plate 108 is minimized. The supporting plates 108 of the two stirring vanes 106a to 106e adjacent to each other along the center line L of the rotating shaft 105 are arranged so as not to overlap each other when viewed along the center line L of the rotating shaft 105 . 7 shows the positional relationship of the two stirring blades 106a and 106b when the stirrer 102 is viewed along the center line L of the rotating shaft 105. Fig. As shown in Fig. 7, each support plate 108 of the stirring vane 106a is positioned between two support plates 108 of the stirring vane 106b. That is, the six support plates 108 of the two stirring vanes 106a and 106b appear to be disposed at positions that are six times symmetrical with respect to the position of the center line L of the rotation shaft 105.

The auxiliary plate 109 is disposed on the main surface of the support plate 108 such that the major surface of the auxiliary plate 109 is perpendicular to the main surface of the support plate 108. The support plate 109 is disposed on the upper main surface and the lower main surface of the support plate 108. As described above, the upper auxiliary plate 119a is disposed on the upper main surface of the support plate 108, and the lower auxiliary plate 119b is disposed on the lower main surface of the support plate 108. [ 4 and 6, the lower side support plate 119b is indicated by a broken line. When the stirring vanes 106a to 106e are viewed along the center line L of the rotary shaft 105, the upper side support plate 119a and the lower side support plate 119b intersect each other.

The auxiliary plate 109 is disposed so as to extend from the vicinity of the rotating shaft 105 toward the outer edge of the support plate 108. [ The auxiliary plate 109 has an inner end portion 109a closest to the rotary shaft 105 and an outer end portion 109b closest to the outer edge of the support plate 108 as an end opposite to the inner end portion 109a have. The auxiliary plate 109 connects the center line L of the rotary shaft 105 and the inner end portion 109a from the inner end portion 109a toward the outer end portion 109b when the stirrer 102 is viewed from above Are arranged to be gradually spaced apart from the straight line (111). In the case of the stirring vanes 106a, 106c and 106e, as shown in Fig. 4, the upper side support plate 119a is moved in a counterclockwise direction from the inner end portion 109a toward the outer end portion 109b 111, and the lower side support plate 119b is disposed so as to be spaced apart from the straight line 111 in the clockwise direction. On the other hand, in the case of the stirring vanes 106b and 106d, as shown in Fig. 6, the upper side support plate 119a extends in the clockwise direction from the inner end portion 109a toward the outer end portion 109b, And the lower auxiliary plate 119b is arranged so as to be spaced apart from the straight line 111 in the counterclockwise direction. That is, in the respective stirring vanes 106a to 106e, the upper side support plate 119a and the lower side support plate 119b are arranged so as to extend in mutually opposite directions. A pair of auxiliary plates 109 opposed to each other are arranged so as to extend in the same direction between the two stirring vanes 106a to 106e adjacent to each other along the center line L of the rotary shaft 105 . For example, both the lower side plate 119b of the stirring vane 106a and the upper side plate 119a of the stirring vane 106b, which is located below the one end of the stirring vane 106a, As shown in Fig.

(2-3) Configuration of the connection portion between the rotary shaft and the stirring wing

Next, the connection between the rotary shaft 105 and the stirring vanes 106a to 106e will be described. Each of the stirring vanes 106a to 106e is attached to the outer peripheral surface of the rotating shaft 105 by fitting. A fitting hole 105a, which is a through hole through which a part of the stirring vanes 106a to 106e is fitted, is formed on the outer peripheral surface of the rotating shaft 105. [ Each of the stirring vanes 106a to 106e is constituted by a main body in which three support plates 108 are connected to each other by a connecting portion 110, three bearings 116 and six wedges 126. [ The bearing 116 is joined to the supporting plate 109 as described later. The wedge 126 is not bonded to the support plate 108 or the bearing 116 but is considered to be one of members constituting the stirring vanes 106a to 106e. Further, the wedge 126 may be bonded to the support plate 108 or the bearing 116.

Each of the bearings 116 has two wedge through holes 116d for passing the wedge 126 therethrough. The wedge 126 is a member having a protrusion that penetrates the wedge through hole 116d of the bearing 116 and is fitted to the fitting hole 105a of the rotating shaft 105. [ Each of the bearings 116 is fixed to the outer peripheral surface of the rotary shaft 105 without being joined to the outer peripheral surface of the rotary shaft 105 by the two wedges 126. [ The stirrer 102 has a bearing 116 in which the wedge through hole 116d is not formed and a wedge 126 that does not penetrate the wedge through hole 116d but is fitted to the fitting hole 105a . A method of attaching the shapes of the bearings 116 and wedges 126 and the respective stirring vanes 106a to 106e to the outer peripheral surface of the rotary shaft 105 by fitting will be described below.

8 is a view showing the arrangement of the rotary shaft 105, the support plate 108 and the bearing 116. Fig. 9 is a side view showing the bearing 116 along the radial direction of the rotary shaft 105 at a height position of the support plate 108. As shown in Fig. In Fig. 9, the supporting plate 108 is indicated by a dotted line. 10 is a top view showing the bearing 116 from above in the vertical direction along the center line L of the rotary shaft 105. As shown in Fig. 10 shows an end face of the rotary shaft 105 and a fitting hole 105a of the rotary shaft 105. As shown in Fig. 11 is a top view showing a state before the wedge 126 of the stirring vanes 106a to 106e is fitted to the rotating shaft 105. Fig. 12 is a top view showing a state after the wedge 126 of the stirring vanes 106a to 106e is fitted to the rotating shaft 105. Fig. 11, the arrows near the wedge 126 indicate the direction in which the wedge 126 is inserted into the wedge through hole 116d of the bearing 116 and the fitting hole 105a of the rotating shaft 105 .

The bearing 116 is composed of an upper end portion 116a and a lower end portion 116b and an axial contact portion 116c between the upper end portion 116a and the lower end portion 116b as shown in Fig. As shown in Fig. 10, the upper end 116a and the lower end 116b are connected to both ends in the horizontal direction of the shaft contact portion 116c having an arcuate shape when viewed from above, in a substantially L-shape . 10, the main surface on the opposite side of the side to which the upper end portion 116a and the lower end portion 116b are connected is in contact with the outer peripheral surface of the rotation shaft 105 as the main surface of the shaft contact portion 116c. 11 and 12, the side surface of the upper end portion 116a is joined to the side surface of the inside end portion 109a of the upper side support plate 119a, and the side surface of the lower end portion 116b is joined to the lower side support plate 119b And is joined to the side surface of the inner end portion 109a. The shaft contact portion 116c and the auxiliary plate 109 are joined to each other by forming a minute gap between the upper end portion 116a and the inner end portion 109a of the upper side support plate 119a, Platinum alloy or the like. The shaft contact portion 116c and the support plate 109 may be joined by welding. Each of the three support plates 108 of the stirring vanes 106a to 106e has one bearing 116 connected to a pair of auxiliary plates 109. [

The shaft contact portion 116c of the bearing 116 is composed of a bearing upper portion 116c1 above the support plate 108 and a lower bearing portion 116c2 below the support plate 108 as shown in Fig. One wedge through hole 116d is formed in the bearing upper portion 116c1 and the lower bearing portion 116c2, respectively. The wedge through hole 116d has a substantially circular cross-sectional shape. The wedge through holes 116d of the bearing upper portion 116c1 of the three bearings 116 are formed at different height positions in the respective stirring vanes 106a to 106e, The wedge through holes 116d of the wedge holes 116c1 and 116c2 are formed at different height positions. A fitting hole 105a is formed in the outer peripheral surface of the rotary shaft 105 at a position communicating with each wedge through hole 116d of the bearing 116 of the stirring vanes 106a to 106e. The fitting hole 105a has a substantially circular cross-sectional shape identical to that of the wedge through hole 116d.

The two wedges 126 are respectively passed through the two wedge through holes 116d of the respective bearings 116 and the two wedge holes 105a of the rotating shaft 105 The respective bearings 116 of the stirring vanes 106a to 106e are fixed to the outer peripheral surface of the rotary shaft 105. [ In other words, each of the stirring vanes 106a to 106e is provided with six wedges 126 fitted to the six fitting holes 105a of the rotating shaft 105 through the three bearings 116, Respectively.

In this embodiment, the wedge 126 has a substantially circular cross-sectional shape and is fitted to the fitting hole 105a of the rotary shaft 105 and the wedge through hole 116d of the bearing 116 Shaped projections. However, the wedge 126 may have any shape with such a projection.

(3) Operation of stirring apparatus

The operation of the stirring apparatus 100 according to the present embodiment will be described. 13 is a view showing the flow of the molten glass G stirred by the stirring apparatus 100. Fig. The arrows shown in Fig. 13 indicate the direction of the flow of the molten glass G. In the inside of the stirring tank 101, the molten glass G flows in the horizontal direction from the upstream side conduit 103. The upper end of the rotating shaft 105 of the stirrer 102 is connected to a motor (not shown). When the stirring device 100 is viewed from above, the stirrer 102 rotates around the center line L of the rotating shaft 105 in the counterclockwise direction. In the inside of the stirring tank 101, the molten glass G is agitated by the stirrer 102 while being gradually guided downward from above. The stirred molten glass G flows out from the inside of the stirring tank 101 to the downstream conduit 104 in a horizontal direction. The temperature of the molten glass G agitated by the stirring apparatus 100 is suitable for a temperature of 1450 to 1750 占 폚 in the case of having a viscosity of 10 ^2.5 dPa 占 퐏 and in the case of 1500 占 폚 to 1750 占 폚 And more suitably in the case of 1530 캜 to 1750 캜.

In the stirring tank 101, the stirring vanes 106a to 106e are rotated by the shaft, whereby the molten glass G is stirred. The auxiliary plate 109 of each of the stirring vanes 106a to 106e scrapes the molten glass G from the inner wall side of the stirring tank 101 toward the rotating shaft 105 side or from the side of the rotating shaft 105 to the stirring tank 101 As shown in Fig. Either one of the upper side support plate 119a and the lower side support plate 119b in the respective stirring vanes 106a to 106e moves the molten glass G from the inner wall side of the stirring tank 101 toward the rotary shaft 105 side And the other extrudes the molten glass G from the rotating shaft 105 side to the inner wall side of the stirring tank 101. That is, the direction of the flow of the molten glass G in the radial direction of the rotating shaft 105 is opposite to the direction above the supporting plate 108 of each of the stirring vanes 106a to 106e and below the supporting plate 108. [ The two stirring blades 106a to 106e which are adjacent to each other along the center line L of the rotary shaft 105 are provided with stirring blades 106a to 106e on the upper and lower sides of the lower side support plate 119b of the upper stirring blades 106a to 106e, 106e are spaced apart from the straight line 111 in the same direction. Therefore, the pair of auxiliary plates 109, which face each other along the center line L of the rotation shaft 105, generate a flow of the molten glass G in the same direction along the radial direction of the rotation shaft 105.

13, the upper side support plate 119a of the uppermost stirring vane 106a is rotated by the shaft rotation of the stirrer 102 so that the molten glass G is guided to the inner wall side of the stirring tank 101 To the rotating shaft 105 side. The lower auxiliary plate 119b of the stirring vane 106a and the upper side auxiliary plate 119a of the stirring vane 106b under one stage of the stirring vane 106a are rotated by stirring the molten glass G from the rotating shaft 105 side Thereby generating a flow of pushing out to the inner wall side of the bath 101. Likewise, the lower side plate 119b of the stirring vane 106b and the upper side plate 119a of the stirring vane 106c are arranged in such a manner that the molten glass G scrapees the molten glass G from the inner wall side of the stirring tank 101 to the rotating shaft 105 side . The lower auxiliary plate 119b of the lower stirring blade 106e of the stirrer 102 generates a flow for pushing the molten glass G from the rotating shaft 105 side to the inner wall side of the stirring tank 101. [ That is, in the lower space 122 between the bottom stirring vane 106e and the bottom surface of the stirring tank 101, the molten glass G flows in the direction of the arrow 124 shown in Fig.

13, the upper side support plate 119a of the uppermost stirring vane 106a is located above the support plate 108 of the stirring vane 106a, The flow of the molten glass G is caused to flow from the side of the rotating shaft 105 toward the side of the rotating shaft 105. The molten glass G moved toward the vicinity of the rotating shaft 105 by the upper side supporting plate 119a of the uppermost stirring wing 106a rises to the liquid level of the molten glass G along the rotating shaft 105. [ The molten glass G rising to the liquid level flows from the rotating shaft 105 side toward the inner wall side of the stirring tank 101 along the liquid level. The molten glass G which has moved to the vicinity of the inner wall of the stirring tank 101 descends to the uppermost stirring vane 106a along the inner wall of the stirring tank 101. [ That is, the circulating flow 123 of the molten glass G shown in Fig. 13 is formed in the upper space 121 between the uppermost stirring vane 106a and the liquid surface of the molten glass G. [ The molten glass G is stirred in the upper space 121 by the circulating flow 123.

In the present embodiment, the radius R of the inner surface of the stirring tank 101 on the cross section orthogonal to the center line L of the rotating shaft 105, the radius of curvature R of the upper surface of the uppermost stirring blade 106a, With respect to the interval H, it is preferable that the ratio R / H is 0.5 to 2.6.

(4) Features

(4-1)

In the stirring apparatus 100 according to the present embodiment, the stirrer 102 is formed of reinforced platinum, and the rotating shaft 105 and the stirring blades 106a to 106e are connected to each other by fitting. The stirring vanes 106a to 106e are rotated by the wedge 126 inserted through the wedge through hole 116d of the bearing 116 and inserted into the fitting hole 105a of the rotating shaft 105, As shown in FIG. Essentially, the stirrer 102 is assembled without welding the rotary shaft 105 and the stirring vanes 106a to 106e by welding.

While the stirring apparatus 100 is stirring the molten glass G, that is, while the stirrer 102 is rotating around the center line L of the rotating shaft 105, the stirring wings 106a to 106e are rotated at a high temperature and a high viscosity The stress due to the stirring of the molten glass G and the stress due to the own weight of the stirring vanes 106a to 106e are received. Since the stirring vanes 106a to 106e are connected to the outer peripheral surface of the rotating shaft 105, the rotating rotating shaft 105 supports both the stresses received by the stirring vanes 106a to 106e. Here, the reinforced platinum, which is the material of the stirrer 102, is heated and melted at a temperature higher than the melting point so that the layered platinum-grain boundary structure collapses and creep strength and tensile strength are lowered to the same extent as that of ordinary platinum or platinum alloy Lt; / RTI > Therefore, in the case where the rotating shaft 105 and the stirring vanes 106a to 106e are joined by welding, the strength of the joining portion of the stirrer is increased by the melting of the reinforced platinum of the joining portion at the time of welding, . Therefore, the stirrer assembled by welding the rotary shaft 105 and the stirring blades 106a to 106e is liable to be deformed and broken during rotation, and there is a fear that the molten glass G can not be homogeneously stirred.

In the present embodiment, the stirrer 102 formed of reinforced platinum is assembled by attaching the stirring vanes 106a to 106e to the outer peripheral surface of the rotating shaft 105 by fitting. Thus, the strength of the agitator 102 can be prevented from lowering as compared with the case where the stirring vanes 106a to 106e are welded to the outer peripheral surface of the rotating shaft 105. [ Therefore, deformation and breakage of the rotating stirrer 102 are suppressed, and the stirrer 102 can be rotated at a high speed from the molten glass G. Therefore, the stirring apparatus 100 of the glass manufacturing apparatus 200 according to the present embodiment can homogenously stir the molten glass G.

Further, the alkali-free glass and alkali-alkali glass having a content of alkali metal oxide of 0% by mass to 2% by mass are more preferable than alkali glass having a content of alkali metal oxide of more than 2% by mass in molten glass The viscosity is high. Therefore, a glass substrate made of an alkali-free glass or an alkali-alkali glass, which is suitable as a glass substrate for FPD and has a small content of alkali metal oxide, is more prone to spoil than a glass substrate made of alkali glass having a large alkali content. That is, in the production process of the glass substrate having a small alkali content, it is important to homogenously stir the molten glass in the stirring apparatus 100 in order to suppress the occurrence of spoilage. The stirring apparatus 100 of the glass manufacturing apparatus 200 according to the present embodiment can rotate the stirrer 102 at a high speed even when the viscosity of the molten glass G is high and therefore the stirring apparatus 100 of the glass- And is suitable for the production of a substrate. Particularly, the stirring apparatus 100 is suitable for the production of a glass substrate made of glass having an alkali metal oxide content of 0 mass% to 0.5 mass%. The content of the alkali metal oxide represents the total amount of the contents of Li ₂ O, Na ₂ O and K ₂ O. Hereinafter, the glass containing substantially no alkali metal oxide is referred to as alkali-free glass, and the glass having the alkali metal oxide content of more than 0% and not more than 2% is referred to as alkali-alkali glass.

Further, the stirring apparatus 100 is suitable for the production of glass substrates for liquid crystal displays and glass substrates for organic EL displays, in which the viscosity of the molten glass in the stirring step is high and strictly the molten glass is required to be strictly excluded.

In addition, since a low-temperature polycrystalline Si (p-Si) TFT and a glass substrate on which an oxide semiconductor is formed require a heat treatment process at a high temperature, the heat shrinkage ratio is preferably small. In order to obtain a glass substrate having a small heat shrinkage ratio, it is preferable to increase the distortion point of the glass. However, since the glass having a high distortion point tends to have a high viscosity at the time of melting, Therefore, the stirring apparatus 100 of the glass manufacturing apparatus 200 according to the present embodiment is suitable for manufacturing a low temperature polycrystalline Si (p-Si) TFT and a glass substrate for an FPD on which an oxide semiconductor is mounted. The distortion point of the glass substrate is preferably 675 DEG C or more, more preferably 680 DEG C or more, and particularly preferably 690 DEG C or more. When the temperature of the glass substrate having a viscosity of 10 ^2.5 dPa 가 is 1400 캜 to 1750 캜, the effect of preventing the deformation and breakage of the stirrer 102 and the effect of homogenizing the molten glass are remarkably exhibited, These effects are more conspicuous when the temperature of the substrate is 1500 ° C. to 1750 ° C., and more remarkably when the temperature of the glass substrate is 1550 ° C. to 1750 ° C.

In addition, in the stirring step, the viscosity of the molten glass in the stirring tank 101 is preferably adjusted to 450 dPa 占 퐏 to 2500 dPa 占 퐏. Particularly, in the case where the viscosity of the molten glass in the stirring tank 101 is 700 dPa · s to 1600 dPa · s in the stirring step, the effect of preventing the deformation and breakage of the stirrer 102 and the effect of homogenizing the molten glass are more remarkable .

(4-2)

The molten glass G that has flowed into the stirring tank 101 from the upstream side conduit 103 is supplied to the inner wall side of the stirring tank 101 by the rotation of the shaft of the stirrer 102 in the stirring apparatus 100 according to the present embodiment, Or from the side of the rotating shaft 105 to the inner wall side of the stirring tank 101 and agitated. The direction of the flow of the molten glass G in the radial direction of the rotating shaft 5 is reversed for each stage of the stirring vanes 106a to 106e along the center line L of the rotating shaft 105 from above to below. That is, the molten glass G is stirred while being alternately moved in the radial direction of the rotating shaft 5 while being guided downward from the inside of the stirring tank 101.

Therefore, the stirring apparatus 100 of the glass manufacturing apparatus 200 according to the present embodiment can homogenously stir the molten glass G without having a complicated structure. As a result, the occurrence of crumbs is suppressed, and a high-quality glass product can be obtained.

(4-3)

In the stirring apparatus 100 according to the present embodiment, an auxiliary plate 109 is disposed on the main surface above and below the support plate 108 of each of the stirring vanes 106a to 106e. When the stirrer 102 rotates, the molten glass G flows in the radial direction of the rotating shaft 105 by the assisting plate 109. Concretely, the molten glass G in the vicinity of the main surface of the support plate 108 is scraped or extruded by the assistance plate 109, thereby moving in the radial direction along the main surface of the support plate 108. Thereby, the molten glass G is sufficiently stirred by the support plate 109 of the stirring vanes 106a to 106e.

Therefore, the stirring apparatus 100 of the glass manufacturing apparatus 200 according to the present embodiment can homogenously stir the molten glass G without having a complicated structure. As a result, the generation of specks of the glass ribbon 44 is suppressed, and a high-quality glass product can be obtained.

(4-4)

The upper assist plate 119a of the stirring vane 106a at the uppermost stage of the stirrer 102 scrapes the molten glass G from the inner wall side of the stirring tank 101 to the rotating shaft 105 side. The molten glass G in the vicinity of the rotating shaft 105 rises along the rotating shaft 105 in the upper space 121 between the uppermost stirring blade 106a and the liquid surface of the molten glass G. [ The molten glass G rising up to the vicinity of the liquid surface of the molten glass G flows toward the inner wall of the stirring tank 101 and descends along the inner wall of the stirring tank 101. Thus, in the upper space 121, the circulating flow 123 of the molten glass G is formed, as shown in Fig.

Here, it is assumed that the molten glass G above the uppermost stirring vane 106a is extruded from the rotating shaft 105 side to the inner wall side of the stirring tank 101, unlike the present embodiment. In this case, when the molten glass G extruded up to the vicinity of the inner wall of the stirring tank 101 moves in the vertical direction along the inner wall of the stirring tank 101, the molten glass G easily flows upward. Therefore, the molten glass G rises up to the vicinity of the liquid surface of the molten glass G along the inner wall of the stirring tank 101. The molten glass G flows from the inner wall side of the stirring tank 101 to the rotating shaft 105 side along the liquid level, and descends along the rotating shaft 105. That is, a circulating flow of the molten glass G in the direction opposite to the circulating flow 123 shown in Fig. 13 is formed.

When the circulating flow in the reverse direction of the molten glass G is formed in the upper space 121 as described above, the downward flow of the molten glass G formed around the rotating shaft 105 is the same as that of the molten glass G, As a result of the volatilization of the easy components, a silica-rich layer containing a relatively large amount of silica components is attracted. Thereby, the molten glass G containing the silica-rich layer is drawn downward from the height position in the vicinity of the liquid surface. As a result, the bubble quality of the glass product may deteriorate and the fume quality may deteriorate.

The molten glass G in the upper space 121 is strongly urged along the outer circumferential surface of the rotary shaft 105 by the rising flow of the molten glass G around the rotary shaft 105, And is prevented from flowing out from the downstream side conduit 104.

Further, in the present embodiment, since the circulating flow 123 of the molten glass G is formed in the upper space 121, the molten glass G is prevented from staying in the vicinity of the liquid surface.

Therefore, the stirring apparatus 100 of the glass manufacturing apparatus 200 according to the present embodiment can homogenously stir the molten glass G. As a result, the generation of specks of the glass ribbon 44 is suppressed, and a high-quality glass product can be obtained.

(4-5)

The molten glass G is extruded from the side of the rotating shaft 105 to the inner wall side of the stirring tank 101 in the lower space 122 between the lower stirring blade 106e and the lower surface of the stirring tank 101. In this embodiment, do. That is, the lower auxiliary plate 119b of the lowermost stirring vane 106e is provided with a flow facilitating the flow of the molten glass G into the downstream conduit 104, as indicated by the arrow 124 in Fig. 13, G. On the other hand, the upper side plate 119a of the lowermost stirring blade 106e and the lower side plate 119b of the stirring wing 106d on the first stage of the stirring wing 106e are arranged on the downstream side of the molten glass G The flow of the molten glass G is suppressed.

The molten glass G agitated by the agitator 102 is likely to flow out from the lower space 122 to the downstream conduit 104. This prevents the molten glass G from staying in the bottom of the stirring tank 101 do. If the molten glass G stays in the bottom of the stirring tank 101, a heterogeneous glass raw material, for example, a zirconia rich layer having a heterogeneous composition, whose composition is out of balance with respect to the average composition of the molten glass G, And is contained in the molten glass G staying therein. If such a molten glass G flows out from the downstream conduit 104, the glass ribbon 44 formed in the molding device 42 may be fogged, which may cause quality problems. Further, when the molten glass G containing the zirconia rich layer is supplied to the molding apparatus 42, the molding apparatus 42 may cause a failure in the molding, causing a problem in quality, It becomes difficult to stably operate the engine, and in the worst case, it is necessary to stop the operation and perform maintenance.

In addition, in the present embodiment, the molten glass G is prevented from flowing out from the space above the lower space 122 to the downstream conduit 104. Thus, the molten glass G in the lower space 122 is always replaced with the molten glass G above the lower space 122, so that the molten glass G is prevented from staying at the bottom of the stirring tank 101. That is, the molten glass G in the stirring tank 101 is surely agitated in each space without short-cutting each space between the adjacent stirring vanes 106a to 106e along the center line L of the rotating shaft 105 . As a result, the molten glass G which is not sufficiently stirred is prevented from flowing out of the stirring apparatus 100.

In this embodiment, as shown in Fig. 13, the upstream-side conduit 103 is disposed in the vicinity of the height position of the uppermost stirring vane 106a. The height position of the uppermost stirring vane 106a is set to be spaced apart from the liquid surface of the molten glass G by a predetermined distance. If the height position of the stirring vane 106a is close to the liquid surface, the liquid surface of the molten glass G is vibrated by the rotation of the shaft of the stirrer 102, so that bubbles floating on the liquid surface are likely to be drawn downward. On the other hand, when the height position of the stirring vane 106a is far from the liquid level, the circulating flow 123 of the molten glass G can not reach the vicinity of the liquid surface, and the molten glass G in the vicinity of the liquid surface is stagnated, And stays near the liquid surface. Therefore, the height position of the stirring vane 106a with respect to the liquid level of the molten glass G is appropriately determined according to the rotation number of the stirrer 102 and the size of the stirring vanes 106a to 106e.

In this embodiment, the flow rate of the molten glass G is adjusted so that the level of the molten glass G is located near the upper end of the upstream-side conduit 103. The support plate 108 of the stirring vane 106a is disposed below the center of the diameter of the upstream-side conduit 103. Specifically, a support plate 108 of a stirring vane 106a is disposed at the same height as the lower end of the upstream-side conduit 103. 13, the upper side auxiliary plate 119a of the uppermost stirring vane 106a generates a flow in the molten glass G that promotes the inflow of the molten glass G from the upstream side conduit 103 .

Therefore, the stirring apparatus 100 of the glass manufacturing apparatus 200 according to the present embodiment can homogenously stir the molten glass G. As a result, the generation of specks of the glass ribbon 44 is suppressed, and a high-quality glass product can be obtained.

(4-6)

7, the supporting plates 108 of the two stirring vanes 106a to 106e adjacent to each other along the center line L of the rotating shaft 105 are arranged along the center line L of the rotating shaft 105 In this case, they are arranged so as not to overlap each other. Thus, the flow of the molten glass G in the vertical direction inside the stirring tank 101 is temporarily blocked by the supporting plate 108 of each of the stirring vanes 106a to 106e. Therefore, in each space between the stirring vanes 106a to 106e adjacent to each other along the center line L of the rotating shaft 105, the molten glass G stays temporarily and is sufficiently stirred.

In the present embodiment, the molten glass G in the upper space 121 is strongly urged along the outer peripheral surface of the rotary shaft 105 by the above-described arrangement of the stirring vanes 106a to 106e, Is prevented from flowing out of the conduit (104).

Therefore, the stirring apparatus 100 of the glass manufacturing apparatus 200 according to the present embodiment can homogenously stir the molten glass G. As a result, the generation of specks of the glass ribbon 44 is suppressed, and a high-quality glass product can be obtained.

(4-7)

When the agitator 102 is viewed along the center line L of the rotary shaft 105 in the stirring apparatus 100 according to the present embodiment, the assistant plate 109 of each of the stirring vanes 106a to 106e has the outer end portion 109b, But is spaced apart from the outer edge of the support plate 108. [ The molten glass G flowing downward along the main surface of the upper side support plate 109a of the stirring vanes 106a to 106e is likely to collide with the upper main surface of the support plate 108 and the lower side of the stirring vanes 106a to 106e The molten glass G flowing upward along the main surface of the auxiliary plate 109b tends to collide with the main surface on the lower side of the support plate 108. [ Thus, the flow of the molten glass G in the vertical direction inside the stirring tank 101 is temporarily blocked by the supporting plate 108 of each of the stirring vanes 106a to 106e. Therefore, in each space between the stirring vanes 106a to 106e adjacent to each other along the center line L of the rotating shaft 105, the molten glass G stays temporarily and is sufficiently stirred.

Therefore, the stirring apparatus 100 of the glass manufacturing apparatus 200 according to the present embodiment can homogenously stir the molten glass G. As a result, the generation of specks of the glass ribbon 44 is suppressed, and a high-quality glass product can be obtained.

(4-8)

In the present embodiment, the three support plates 108 of the stirring vanes 106a to 106e are connected to each other by the connection portion 110 around the rotation shaft 105. [ Thereby, the strength of the stirring vanes 106a to 106e is improved. Further, the stirring effect of the molten glass G around the rotating shaft 105 is small, and the molten glass G is not sufficiently stirred and is easily lowered in the vicinity of the rotating shaft 105. The connecting portion 110 of each of the stirring vanes 106a to 106e can suppress the downward flow of the molten glass G in the vicinity of the rotating shaft 105. [

Therefore, the stirring apparatus 100 of the glass manufacturing apparatus 200 according to the present embodiment can homogenously stir the molten glass G. As a result, the generation of specks of the glass ribbon 44 is suppressed, and a high-quality glass product can be obtained.

(5) Modifications

(5-1) Modification Example A

In the present embodiment, five stirring blades 106a to 106e are arranged at equal intervals along the center line L on the rotating shaft 105 of the stirrer 102. [ However, the number of the stirring blades 106a to 106e attached to the rotating shaft 105 may be appropriately set in consideration of the size of the stirring tank 101, the length of the rotating shaft 105, and the like. The distance between two adjacent stirring blades 106a to 106e along the center line L of the rotating shaft 105 is appropriately set in consideration of the size of the stirring tank 101 and the length of the rotating shaft 105 do.

(5-2) Variation B

In the present embodiment, each of the stirring vanes 106a to 106e of the agitator 102 has three support plates 108, but may have two or more support plates 108. [

By way of example, FIG. 14 shows a stirrer 2 having a stirring blade having two support plates. The stirrer 2 has five stirring blades 6a to 6e fixed to the rotating shaft 5 like the stirrer 102 of the present embodiment. Two auxiliary plates are respectively arranged on the upper main surface and the lower main surface of the support plate of each of the stirring vanes 6a through 6e.

When the agitator 102 is viewed along the center line L of the rotary shaft 105 as in the present embodiment, when each of the stirring vanes 106a to 106e has four support plates 108, The positions of the support plates 108 of the two adjacent stirring vanes 106a to 106e may be different from each other.

(5-3) Variation C

The support plate 108 of each of the stirring vanes 106a to 106e in this embodiment may have a through hole 112 formed in its main surface. 15 is a plan view of stirring vanes 106a, 106c, and 106e having through holes 112. Fig. In this modification, when the agitator 102 is rotated, a part of the molten glass G passes through the through hole 112, and a flow of the molten glass G in the vertical direction is generated. Thereby, in the molten glass G, a flow in the axial direction of the rotating shaft 105 is generated by the through hole 112, in addition to the flow in the radial direction of the rotating shaft 105 by the auxiliary plate 109. Therefore, a more complicated flow is generated in the molten glass G, so that a higher stirring effect is obtained. In addition, it is expected that the through-hole 112 allows the shaft-rotating stirrer 102 to receive a small resistance from the molten glass G, and the stirring apparatus 100 can stir the molten glass G with less energy .

Further, in this modification, the bubbles included in the molten glass G can pass through the through hole 112 and rise to the liquid level of the molten glass G. Thereby, the bubbles contained in the molten glass G are efficiently removed. For example, when the stirrer 102 of this modification is put into the molten glass G of the stirring tank 101 when the stirrer 102 is inspected and repaired or when the use of the new stirrer 102 is started, think. In this case, the bubbles of the air, which are dried when the agitator 102 is put in, pass through the through holes 112 of the stirring vanes 106a to 106e and rapidly float. Therefore, the time required for stable operation of the stirring apparatus 100 can be shortened.

15, through holes 112 may also be formed in the connecting portions 110 connecting the support plates 108 of the respective stirring vanes 106a to 106e.

(5-4) Variation example D

The stirring apparatus 100 according to the present embodiment may be provided with a mechanism for discharging the molten glass G from the stirring tank 101. [ For example, a discharge port for discharging the molten glass G containing the zirconia rich layer may be formed on the bottom surface of the stirring tank 101. Further, a discharge port for discharging the molten glass G containing the bubbles or the silica rich layer may be formed on the side surface of the stirring tank 101.

In the molten glass G, there may be a case where a heterogeneous glass raw material having a balanced composition is broken in relation to the average composition of the molten glass G. This is considered to be attributable to the unevenness of the composition of the molten glass G generated in the melting tank 40, or to the volatilization of the component that is easily volatilized from the molten glass G. Particularly, a heterogeneous glass raw material due to volatilization of a component that is easily volatilized from the molten glass G tends to stay on the surface of the molten glass G of the stirring tank 101.

13, in the case where the circulation flow 123 is formed in the upper space 121, even if bubble or heterogeneous glass material exists on the surface of the molten glass G, The molten glass G flows from the rotating shaft 105 side toward the inner wall side of the stirring tank 101 along the liquid level. Therefore, by forming the discharge port on the extension line of the flow of the molten glass G, it is possible to discharge the bubble or heterogeneous glass raw material contained in the molten glass G. The stirring vessel 101 may be provided with a discharge port at a height position higher than the uppermost stirring vane 106a, preferably at a height position just below the liquid level or the liquid level of the molten glass G. This outlet is formed on the side surface of the stirring tank 101, and a discharge pipe is connected. A part of the molten glass G in the vicinity of the liquid surface is discharged from the outlet of the stirring tank 101.

Generally, when foreign matters contained in the molten glass G are to be removed, it is necessary to stop the operation of the stirring apparatus 100. However, when the circulation flow 123 is formed in the upper space 121 and a flow from the side of the rotating shaft 105 to the inner wall side of the stirring tank 101 is formed in the vicinity of the liquid surface of the molten glass G, 101, the molten glass G containing bubble or heterogeneous glass raw material can be discharged from the stirring tank 101 without stopping the operation of the stirring apparatus 100. [ For example, even when a molten glass G containing a large amount of bubbles flows into the stirring tank 101 from the blue sign 41, a small amount of molten glass G containing bubbles can be obtained without stopping the operation of the stirring device 100 And can be discharged from the stirring tank 101.

(5-5) Variation E

The supporting plates 108 of the two stirring vanes 106a to 106e adjacent to each other along the center line L of the rotating shaft 105 are arranged so as not to overlap each other when viewed along the center line L of the rotating shaft 105 . Each of the stirring vanes 106a to 106e is formed in such a manner that the supporting plate 108 of the stirring vanes 106a to 106e disposed at the two adjacent ends of the stirring vanes 106a to 106e, The space between the support plate 108 and the support plate 108 may be minimized or the area where the support plate 108 and the support plate 108 overlap may be minimized.

(5-6) Variation Example F

The molten glass G agitated by the stirring apparatus 100 according to the present embodiment is not limited to the above-mentioned composition and is not limited to the above-mentioned values of the temperature and the viscosity. The composition of the above-mentioned molten glass G is the glass composition of the alkali-free glass or the alkali-alkali glass used for the glass substrate for FPD.

However, the stirring apparatus 100 may be used for stirring a molten glass G having a glass composition for tempered glass, which contains more alkali components. In this case, it is preferable to set the temperature of the molten glass G within the range of 1300 ° C to 1400 ° C, which is lower than that of the present embodiment, and stir the molten glass G.

(5-7) Variation example G

In the stirrer 102 according to the present embodiment, each of the stirring vanes 106a to 106e is fixed to the rotating shaft 105 by the wedge 126. However, each of the stirring vanes 106a to 106e may be fixed to the rotating shaft 105 by using another means. For example, as in the case of joining between the upper end portion 116a and the inner end portion 109a of the upper side support plate 119a, there is a gap between the bearing 116 of the stirring vanes 106a to 106e and the outer peripheral surface of the rotation shaft 105 A gap may be formed and the gap may be filled with molten platinum or a platinum alloy or the like so that the stirring vanes 106a to 106e may be firmly fixed by the rotation shaft 105. [ The stirring vanes 106a to 106e may be firmly fixed to the rotating shaft 105 by welding so that the strength of the reinforced platinum of the stirrer 102 and the rotating shaft 105 is not significantly lowered.

(5-8) Modification H

In the stirrer 102 according to the present embodiment, each of the stirring vanes 106a to 106e is fixed to the rotating shaft 105 by the wedge 126. [ However, the support plate 108 of each of the stirring vanes 106a to 106e is directly fitted into the groove formed in the outer peripheral surface of the rotation shaft 105 without using the wedge 126, so that each of the stirring vanes 106a- May be fixed to the rotary shaft 105.

A part of each of the stirring vanes 106a to 106e is fit into a recess or a hole or the like formed in the outer circumferential surface of the rotary shaft 105 so that each of the stirring vanes 106a to 106e is fitted to the rotary shaft 105 Is fixed.

(5-9) Modification I

Alkali glass and alkali-alkali glass having the above-mentioned composition have been described as an example of the glass substrate manufactured by the glass manufacturing apparatus 200 according to the present embodiment. However, the glass substrate for FPD is preferably a glass substrate having an SiO _{2 content of} 50% 70 wt%, Al ₂ O _3: 5% by mass to 25% by weight, B ₂ O _3: 0 wt% to 15 wt%, MgO: 0 mass% to 10 mass%, CaO: 0% by mass to 20% by weight, , 0 mass% to 20 mass% of SrO, and 0 mass% to 10 mass% of BaO. The glass substrate may contain 5 mass% to 20 mass% of other oxides.

Further, a glass substrate produced by a glass manufacturing apparatus 200 according to this embodiment, SiO _2: 52 wt% ~78 wt%, Al ₂ O _{3: 3%} by mass to 25% by weight, B ₂ O _3: 3 mass% to 15 mass%, RO 3 mass% to 20 mass% of RO (total amount of MgO, CaO, SrO and BaO), R ₂ O (provided that R ₂ O is Li ₂ O, Na ₂ O, and containing 0 mass% ~0.3% by weight and does not substantially free of as ₂ O _3, the weight ratio CaO / RO is at least 0.65: total amount) 0.01% ~0.8% by weight of K ₂ O, Sb ₂ O ₃ The mass ratio (SiO ₂ + Al ₂ O ₃ ) / B ₂ O ₃ is 7 to 30, the mass ratio (SiO ₂ + Al ₂ O ₃ ) / RO is 5 or more, and the distortion point is 688 ° C. or more. Or a glass substrate.

Further, in the glass substrate for FPD, a substrate of alkali-free glass is preferable in order to suppress breakdown of the TFT. However, in order to improve the refinability of the molten glass G in the blue sign 41, the glass substrate preferably contains 0.05% by mass to 2% by mass, preferably 0.1% by mass to 2% by mass of Li ₂ O, Na ₂ O, and K ₂ O may be contained. Further, in order to reduce the burden on the environment, it is preferable that the glass substrate does not contain As ₂ O ₃ or PbO as a fining agent. Further, the glass substrate preferably contains at least tin oxide as a fining agent, and it preferably contains iron oxide in an amount of 0.01 mass% to 0.2 mass%. In order to reduce the weight, the glass substrate preferably contains 0 mass% to 10 mass% of SrO and BaO in total, and in this case, the content of BaO is 0 mass% to 2 mass % Is more preferable.

(5-10) Variation example J

In the glass manufacturing apparatus 200 according to the present embodiment, the stirring apparatus 100 stirs the molten glass G provided between the blue sign 41 and the molding apparatus 42 and refined in the blue sign 41 . However, the stirring apparatus 100 may be provided between the melting tank 40 and the blue sign 41. [ In this case, the stirring apparatus 100 stirs the molten glass G generated in the melting tank 40, and supplies the homogenized molten glass G to the blue sign 41. [ Two stirring devices 100 may be provided between the melting tank 40 and the blue sign 41 and between the blue sign 41 and the molding device 42. [

In the glass manufacturing apparatus 200 for producing a glass substrate for FPD, the molten glass G agitated in the stirring apparatus 100 provided between the melting tank 40 and the blue bulb 41 is heated to 1500 to 1600 DEG C Lt; 0 > C.

≪ Second Embodiment >

A second embodiment of a method for manufacturing a glass substrate, an apparatus for manufacturing a glass substrate and a stirring apparatus according to the present invention will be described with reference to the drawings. The basic configuration, operation, and characteristics of the glass manufacturing apparatus of the present embodiment are the same as those of the glass manufacturing apparatus of the first embodiment. The same reference numerals are used for elements having the same structure and function as those of the first embodiment.

(1) Configuration

The glass manufacturing apparatus of the present embodiment has a configuration in which the stirring apparatus 100 of the glass manufacturing apparatus 200 of the first embodiment shown in Fig. 1 is replaced with a stirring apparatus 1100 having a configuration different from that of the stirring apparatus 100 have. 16 is a side view of the stirring apparatus 1100. Fig. The stirring apparatus 1100 includes a first stirring tank 1101a and a second stirring tank 1101b. The first stirring tank 1101a and the second stirring tank 1101b have the same cylindrical shape as the stirring tank 101 of the first embodiment. The first stirring tank 1101a has an upstream side conduit 1103 attached to the lower side. The second stirring tank 1101b has a downstream side conduit 1104 attached to the lower side surface. The arrows shown in Fig. 16 show the direction of the flow of the molten glass G stirred in the stirring apparatus 1100. Fig.

The stirring step of stirring the molten glass G in the stirring apparatus 1100 includes a first stirring step of stirring the molten glass G while guiding the molten glass G upward from below in the first stirring tank 1101a, And a second stirring step of stirring the molten glass G stirred in the first stirring step while guiding the molten glass G from the upper side downward in the tank 1101b. The first stirring tank 1101a has a first stirrer 1102a for stirring the molten glass G therein and a first discharge pipe 1110a for discharging the molten glass G from the bottom. The second stirring tank 1101b includes a second agitator 1102b for stirring the molten glass G therein and a second drain pipe 1110b for discharging the molten glass G from the liquid level LL of the molten glass G therein . The upper side surface of the first stirring tank 1101a is connected to the upper side surface of the second stirring tank 1101b by a connecting pipe 1107. [ The molten glass G is sent from the first stirring tank 1101a to the second stirring tank 1101b through the connecting pipe 1107. [ The first stirrer 1102a and the second stirrer 1102b are formed of reinforced platinum similarly to the stirrer 102 of the first embodiment.

The first stirrer 1102a includes a first rotating shaft 1105a disposed along the vertical direction and a second rotating shaft 1105b fixed to the outer circumferential surface of the first rotating shaft 1105a and extending from the uppermost stage to the lowermost stage along the first rotating shaft 1105a, And has four first stirring blades 1106a1 to 1106a4 arranged therein. The first stirring vanes 1106a1 to 1106a4 have a first support plate orthogonal to the first rotation shaft 1105a and a first support plate disposed on the main surface above and below the first support plate. The second agitator 1102b includes a second rotating shaft 1105b disposed along the vertical direction and a second rotating shaft 1105b fixed to the outer circumferential surface of the second rotating shaft 1105b and extending along the second rotating shaft 1105b from the uppermost stage to the lowermost stage, And five second stirring blades 1106b1 to 1106b5 arranged therein. The second stirring vanes 1106b1 to 1106b5 have a second support plate orthogonal to the second rotation shaft 1105b and a second support plate disposed on the main surface above and below the second support plate.

In the first stirring step, the first stirrer 1102a rotates around the first rotating shaft 1105a, so that the first subsidiary plate generates a flow in the radial direction of the first rotating shaft 1105a in the molten glass G. In the second stirring step, the second stirrer 1102b rotates around the second rotating shaft 1105b, so that the second assisting plate causes the molten glass G to flow in the radial direction of the second rotating shaft 1105b.

The first stirring blades 1106a1 to 1106a4 of the first stirrer 1102a and the second stirring blades 1106b1 to 1106b5 of the second stirrer 1102b are provided in the stirring blade 106a to 106e. The first support plate and the first support plate of the first stirring vanes 1106a1 to 1106a4 correspond to the support plate 108 and the assisting plate 109 of the first embodiment, respectively. The second support plate and the second support plate of the second stirring vanes 1106b1 to 1106b5 correspond to the support plate 108 and the assisting plate 109 of the first embodiment, respectively. The first stirring vanes 1106a1 to 1106a4 and the second stirring vanes 1106b1 to 1106b5 have a configuration corresponding to the bearings 116 and the wedges 126 of the stirring vanes 106a to 106e of the first embodiment I have. The direction of the flow of the molten glass G formed by the first stirrer 1102a and the second stirrer 1102b will be described later.

In addition, in the first stirring step, the first subsidiary plate positioned between the first support plates of the first stirring vanes 1106a1 to 1106a4 disposed at the two adjacent stages generates a flow in the same direction in the molten glass G . In the second stirring step, the second subsidiary plate positioned between the second support plates of the second stirring vanes 1106b1 to 1106b5 disposed at the two adjacent stages generates a flow in the molten glass G in the same direction.

Further, in the first stirring step, the first sub-plate disposed on the upper main surface of the first support plate of the uppermost first stirring vane 1106a1 is located above the upper side of the first support plate of the uppermost first stirring vane 1106a1 The molten glass G moved by the first flow is supplied to the first rotating shaft 1105a by generating the first flow for moving the molten glass from the inner wall of the first stirring tank 1101a toward the first rotating shaft 1105a, Thereby raising the second flow. Thereby, in the first stirring step, in the space 1121a between the uppermost first stirring vane 1106a1 and the liquid level LL of the molten glass G, as indicated by the arrow 1123a in Fig. 16, A circulating flow of the molten glass G is formed.

Further, in the second stirring step, the second sub-plate disposed on the upper main surface of the second support plate of the uppermost second stirring vane 1106b1 is located above the second support plate of the uppermost second stirring vane 1106b1 The molten glass G moved by the third flow is supplied to the second rotary shaft 1105b by the third flow that moves the molten glass G from the inner wall of the second stirring tank 1101b toward the second rotary shaft 1105b ) In accordance with the fourth flow. Thus, in the second stirring step, in the space 1121b between the uppermost second stirring vane 1106b1 and the liquid level LL of the molten glass G, as indicated by the arrow 1123b in Fig. 16, similarly to the first embodiment, A circulating flow of the molten glass G is formed.

The first stirring tank 1101a has an inlet for horizontally flowing the molten glass G into the first stirring tank 1101a in the vicinity of the height position of the lowermost first stirring vane 1106a4. The second stirring tank 1101b has an outlet for discharging the molten glass G from the second stirring tank 1101b in the horizontal direction in the vicinity of the height position of the lowermost second stirring vane 1106b5.

In the first stirring step, the first stirrer 1102a rotates around the first rotating shaft 1105a so that in each of the first stirring vanes 1106a1 to 1106a4, the upper surface of the first supporting plate One of the first subsidiary plates arranged on the lower main surface of the first support plate and the first subsidiary plate disposed on the lower main surface of the first support plate are provided with a flow from the inner wall of the first stirring tank 1101a toward the first rotary shaft 1105a And the other first auxiliary plate generates a flow in the molten glass G from the first rotation shaft 1105a toward the inner wall of the first stirring tank 1101a. In the second stirring step, the second stirrer 1102b is rotated around the second rotating shaft 1105b so that the second stirring vanes 1106b1 to 1106b5 are arranged on the upper main surface of the second supporting plate 1106b One of the second subsidiary plates arranged on the lower main surface of the second subsidiary plate and the second support plate is configured so that the flow from the inner wall of the second stirring tank 1101b toward the second rotary shaft 1105b is made into molten glass G and the other second auxiliary plate generates a flow from the second rotating shaft 1105b toward the inner wall of the second stirring tank 1101b in the molten glass G.

In the first stirring step, the first auxiliary plate of the first stirring vane 1106a4 in the space 1122a between the first stirring vane 1106a4 at the lowermost stage and the bottom surface of the first stirring tank 1101a, The flow from the inner wall of the first stirring tank 1101a toward the first rotating shaft 1105a is generated in the molten glass G as indicated by the arrow 1624 in Fig. The first auxiliary plate of the first stirring vanes 1106a3 and 1106a4 is disposed between the first stirring vane 1106a4 at the lowest stage and the first stirring vane 1106a3 located at the lowest stage at the first stage, And flows into the molten glass G from the rotating shaft 1105a toward the inner wall of the first stirring tank 1101a. The second auxiliary plate of the second stirring vane 1106b5 in the space 1122b between the bottom surface of the second stirring vane 1101b and the bottom surface of the second stirring vane 1101b, The flow from the second rotation shaft 1105b toward the inner wall of the second stirring tank 1101b is generated in the molten glass G as indicated by an arrow 1124b. The second auxiliary plate of the second stirring vane 1106b4 and 1106b5 is disposed between the second stirring vane 1106b5 located at the lowermost stage and the second stirring vane 1106b4 positioned at the lowermost stage of the first stage, A flow from the inner wall of the stirring tank 1101b toward the second rotating shaft 1105b is generated in the molten glass G.

(2) Features

In this embodiment, the molten glass G passed through the conduit 43b from the blue bulb 41 to the stirring device 1100 is stirred in the first stirring tank 1101a, 1101b. In the first stirring tank 1101a, the molten glass G introduced in the horizontal direction from the upstream-side conduit 1103 is stirred while being directed upward from below. The molten glass G stirred in the first stirring tank 1101a is sent to the second stirring tank 1101b through the connecting pipe 1107. [ In the second stirring tank 1101b, the molten glass G is stirred while being guided downward from above, and flows out in the horizontal direction from the downstream side conduit 1104.

In the stirring apparatus 1100, molten glass G containing a component having a high specific gravity, for example, a zirconia rich layer contained in the molten glass G is stored in the bottom of the first stirring tank 1101a. Since the molten glass G rises inside the first stirring tank 1101a and is sent to the second stirring tank 1101b, the component having a large specific gravity, which is stored in the bottom of the first stirring tank 1101a, It is difficult to flow into the tank 1101b. A first outlet pipe 1110a is attached to the bottom of the first stirring tank 1101a. As a result, a component having a large specific gravity stored in the bottom of the first stirring tank 1101a can be discharged from the first stirring tank 1101a through the first discharge pipe 1110a.

In the first stirring tank 1101a, a molten glass G containing a component having a low specific gravity, for example, a bubble or a silica rich layer, contained in the molten glass G is stored in the vicinity of the liquid level LL of the molten glass G. The component having a small specific gravity present in the first stirring tank 1101a is supplied to the first stirring tank 1101a through the connection pipe 1107 connecting the first stirring tank 1101a and the second stirring tank 1101b together with the molten glass G, And sent to the second stirring tank 1101b. That is, the component having a small specific gravity contained in the molten glass G is finally stored in the vicinity of the liquid level LL of the molten glass G in the second stirring tank 1101b. A second discharge pipe 1110b is attached to the second stirring tank 1101b at a height position near the liquid level LL of the molten glass G. As a result, a component having a small specific gravity stored in the vicinity of the liquid level LL of the molten glass G can be discharged from the second stirring tank 1101b through the second discharge pipe 1110b.

In this embodiment, similarly to the first embodiment, the first agitator 1102a formed of reinforced platinum is attached to the outer peripheral surface of the first rotating shaft 1105a by fitting the first agitating blades 1106a1 to 1106a4 . Thus, the strength of the first agitator 1102a is prevented from lowering, as compared with the case where the first stirring vanes 1106a1 to 1106a4 are welded to the outer peripheral surface of the first rotating shaft 1105a. The second stirring blades 1106b1 to 1106b5 of the second stirrer 1102b are likewise assembled by fitting, so that a reduction in strength is suppressed. Therefore, deformation and breakage during the rotation of the first stirrer 1102a and the second stirrer 1102b are suppressed, so that the first stirrer 1102a and the second stirrer 1102b among the high-temperature and high-viscosity molten glass G It becomes possible to rotate at high speed. Therefore, the stirring apparatus 1100 of the glass manufacturing apparatus according to the present embodiment can homogenously stir the molten glass G.

The stirring device 1100 of the present embodiment has the above-described characteristics of the stirring device 100 of the first embodiment and can appropriately control the above-described modification of the stirring device 100 of the first embodiment Can be adopted.

≪ Third Embodiment >

A third embodiment of a method for manufacturing a glass substrate, an apparatus for manufacturing a glass substrate and a stirring apparatus according to the present invention will be described with reference to the drawings. The basic configuration, operation, and characteristics of the glass manufacturing apparatus of the present embodiment are the same as those of the glass manufacturing apparatus of the first embodiment. The same reference numerals are used for elements having the same structure and function as those of the first embodiment.

(1) Configuration

The difference between the present embodiment and the first embodiment is the shape of an assisting plate of a stirring blade of an agitator. Fig. 17 shows a top view of one of the three support plates 208 of the stirring vanes 206a to 206e of the stirrer of the present embodiment. 17 is a plan view of the upper side support plate 219a disposed on the upper main surface 208a of the support plate 208. Fig. 18 is a longitudinal sectional view of the upper side support plate 219a taken along the line XVIII-XVIII in Fig. Fig. 19 is a side view of the upper side support plate 219a seen from the infinite circle along the direction of arrow XIX in Fig. 20 is a side view of the outer end portion 209b of the upper side support plate 219a viewed along the direction of arrow XX in Fig. 21 is a cross-sectional view of the upper side support plate 219a on the line XXI-XXI in Figs. 18 and 19. Fig.

Each of the stirring vanes 206a to 206e has three supporting plates 208 arranged around the rotating shaft 205 like the stirring vanes 106a to 106e of the first embodiment. Each support plate 208 has an upper support plate 219a disposed on the upper main surface and two auxiliary plates composed of a lower support plate disposed on the lower main surface. The upper side support plate 219a has an inner end portion 209a closest to the rotary shaft 205 and an outer end portion 209b closest to the outer edge of the support plate 208 as an end opposite to the inner end portion 209a I have. The end portion of the auxiliary plate, which is separated from the main surface of the support plate 208 connected to the auxiliary plate, is curved along the vertical direction toward the rotating shaft 205 as an end portion in the vertical direction. The outer end portion 209b, which is the end that is the farthest from the rotary shaft 205 in the radial direction, is curved along the horizontal direction toward the rotary shaft 205 as the horizontal end of the assisting plate. Next, specific shapes of the upper side support plate 219a and the lower side support plate will be described.

As shown in Fig. 18, the upper side support plate 219a extends upward from the main surface 208a above the support plate 208 in the vertical direction. The upper auxiliary plate 219a is composed of a plate lower portion 219a1 and a plate upper portion 219a2. The plate lower portion 219a1 extends perpendicularly to the main surface 208a. The plate upper portion 219a2 is curved toward the inside of the curved surface of the upper side support plate 219a viewed along the rotation axis 205, that is, toward the rotation shaft 205 side.

As shown in Figs. 19 and 20, the plate upper portion 219a2 of the outer end portion 209b of the upper side support plate 219a has a hemispherical dome shape. As shown in Fig. 21, the outer end portion 209b of the upper side support plate 219a is curved in a semicircular shape toward the rotation shaft 205. As shown in Fig.

The lower auxiliary plate has the same shape as the upper auxiliary plate 219a. More specifically, when the upper auxiliary plate 219a is removed from the upper main surface of the support plate 208 and attached to the lower main surface of the support plate 208 in the upside down direction, the lower auxiliary plate 219a has the same shape and arrangement as the lower auxiliary plate.

(2) Features

In the stirring apparatus provided with the stirrer of the present embodiment, the upper side support plate 219a of the stirring vanes 206a to 206e and the end portion of the lower side support plate are curved. Thus, when the molten glass G is stirred by the rotation of the shaft of the stirrer, the molten glass G can smoothly flow along the curves of the upper side support plate 219a and the lower side support plate. Therefore, while the stirrer is stirring the molten glass G, the generation of the negative pressure region, which is a space having a lower pressure than the pressure of the surrounding space, is suppressed in the vicinity of the upper side supporter 219a and the end of the lower side supporter. In the negative pressure region, the pressure of the molten glass G is lower than the ambient, and the amount of the gas dissolved in the molten glass G is lowered, so that bubbles are likely to be generated. If the upper auxiliary plate 219a has the above-mentioned curved portion in the case where no flow is generated by the auxiliary plate to extrude the molten glass G in the radial direction of the stirring tank, the lower auxiliary plate may have the above- do.

In the present embodiment, the end portions of the auxiliary plates of the stirring vanes 206a to 206e are curved so that the negative pressure region is prevented from being generated during stirring of the molten glass G. Therefore, the stirrer having such a stirrer can further increase the rotating speed of the stirrer without concern about the occurrence of bubbles due to the generation of the negative pressure region, and therefore, the molten glass G can be stirred more homogeneously. As a result, the generation of specks of the glass ribbon 44 is suppressed, and a high-quality glass product can be obtained.

The stirring device of the present embodiment has the above-described characteristics of the stirring device 100 of the first embodiment and can appropriately employ the above-described modification of the stirring device 100 of the first embodiment have.

<Examples>

A glass substrate was produced using the glass manufacturing apparatus according to the present invention. The glass substrate had a glass composition of 60 mass% SiO ₂ , 10 mass% B ₂ O ₃ , 19.5 mass% Al ₂ O ₃ , 5.3 mass% CaO, 5 mass% SrO, 0.2 mass% SnO ₂ , . Initially, in the melting tank, the glass raw material was melted so as to have the above composition to obtain a molten glass. Next, the molten glass obtained in the melting tank was subjected to refining by raising the temperature at 1650 DEG C in the blue oven.

Next, the molten glass after the refining was stirred using an agitator equipped with a stirrer formed of dispersed reinforced platinum. The stirrer had a rotating shaft and a stirring blade fitted to the rotating shaft and fixed to the outer peripheral surface of the rotating shaft. The number of revolutions of the stirrer was 12.5 rpm. Next, the molten glass stirred in the stirring apparatus was supplied to a molding apparatus, and a glass ribbon was formed by an overflow downloading method.

Next, the glass ribbon was cut to produce a glass substrate for FPD having a thickness of 0.7 mm and a size of 2200 mm x 2500 mm. As a result, even if the production of the glass substrate is continued for two years by using the glass manufacturing apparatus according to the present invention, the glass substrate for FPD can be produced well, and further, the manufacturing abnormality due to the deformation and breakage of the stirring apparatus It was not.

Further, by using the apparatus for producing glass according to the present invention, it is possible to produce a glass composition which contains 61.5 mass% of SiO ₂ , 9 mass% of B ₂ O ₃ , 19 mass% of Al ₂ O ₃ , 10 mass% of CaO, 0.3 mass of alkali metal oxide %, Fe ₂ O ₃ : 0.05% by mass, and SnO ₂ : 0.15% by mass. Even in this case, the production of the glass substrate for FPD can be performed well, and the manufacturing abnormality due to the deformation and breakage of the stirring apparatus was not recognized.

40: Melting bath (melted part)
42: Molding device (molded part)
100: Stirring apparatus (stirring section)
101: stirring tank
102: stirrer
105:
105a: Fitting hole
106a to 106e: stirring wing
108: Support plate
109:
126: Wedge (fitting projection)
200: Glass manufacturing apparatus (glass substrate production apparatus)
G: molten glass
L: Center line of the rotating shaft

Claims (12)

A method for producing a glass substrate comprising a melting step of melting glass raw material to obtain a molten glass and a stirring step of stirring the molten glass obtained in the melting step,
In the stirring step, the molten glass is stirred by an agitator disposed in the stirring tank while being guided from the upper side downward or from the lower side into the stirring tank,
Wherein the agitator has a rotating shaft disposed along the vertical direction and a stirring blade which is fixed to the outer peripheral surface of the rotating shaft by being fitted to the rotating shaft and is arranged at a plurality of stages from the uppermost stage to the lowermost stage along the rotating shaft, The portion where the wing is fitted to the rotation shaft and the vicinity thereof are formed of reinforced platinum,
Wherein the rotary shaft has a cavity inside and is formed on an outer peripheral surface thereof and has a fitting hole into which a part of the stirring blade is fitted,
Wherein the stirring blade has a fitting protrusion that is fitted to the fitting hole of the rotating shaft and the fitting protrusion is fixed to the outer circumferential surface of the rotating shaft by being inserted into the fitting hole of the rotating shaft,
A method of manufacturing a glass substrate. A method for producing a glass substrate comprising a melting step of melting glass raw material to obtain a molten glass and a stirring step of stirring the molten glass obtained in the melting step,
In the stirring step, the molten glass is stirred by an agitator disposed in the stirring tank while being guided from the upper side downward or from the lower side into the stirring tank,
Wherein the agitator has a rotating shaft disposed along the vertical direction and a stirring blade which is fixed to the outer peripheral surface of the rotating shaft by being fitted to the rotating shaft and is arranged at a plurality of stages from the uppermost stage to the lowermost stage along the rotating shaft, The portion where the wing is fitted to the rotation shaft and the vicinity thereof are formed of reinforced platinum,
Wherein the rotary shaft has an internal cavity and is formed on an outer peripheral surface thereof and has a fitting hole for fitting the fitting projection of the wedge for fixing the rotary shaft and the stirring vane,
Wherein the stirring wing has a wedge through hole for allowing the wedge to pass therethrough and the wedge is passed through the wedge through hole and the fitting projection is fitted to the fitting hole so that the wedge is fixed to the outer peripheral surface of the rotating shaft In addition,
A method of manufacturing a glass substrate. 3. The method according to claim 1 or 2,
Wherein the molten glass agitated by the agitator in the stirring step is a glass having a viscosity of 10 ^2.5 dPa s at a temperature of 1450 캜 or higher. 3. The method according to claim 1 or 2,
Wherein the glass substrate has an alkali metal oxide content of 0 mass% to 2 mass%. 3. The method according to claim 1 or 2,
Wherein the glass substrate is any one of a glass substrate for a liquid crystal display and a glass substrate for an organic EL display. 3. The method according to claim 1 or 2,
Wherein the stirring blade has a support plate perpendicular to a center line of the rotation shaft and an assisting plate disposed on a main surface above and below the support plate,
In the stirring step, the stirrer rotates about the center line of the rotating shaft, so that the assisting plate generates a flow in the radial direction of the rotating shaft in the molten glass, and further, The auxiliary plate located between the support plates of the wings generates a flow in the same direction in the molten glass. The method according to claim 6,
Wherein the stirring plate is rotated around the center line of the rotating shaft in each of the stirring vanes so that the stirring plate is disposed on the main plate below the support plate and on the main plate above the support plate, The auxiliary plate of one of the auxiliary plates generates a flow toward the rotating shaft from the inner wall of the stirring tank to the molten glass while the other auxiliary plate causes a flow from the rotating shaft to the inner wall of the stirring tank to occur in the molten glass Wherein the glass substrate is a glass substrate. 3. The method according to claim 1 or 2,
Wherein the stirring step comprises a first stirring step of stirring the molten glass while guiding the molten glass upward from below in the first stirring tank and a second stirring step of stirring the molten glass stirred in the first stirring step inside And a second agitating step of stirring the mixture while being guided downward,
Wherein the first stirring vessel comprises a first chamber, a first stirrer for stirring the molten glass in the first chamber, and a first outlet pipe through which the molten glass can be discharged from the bottom of the first chamber,
The second stirring vessel may include a second chamber, a second stirrer for stirring the molten glass in the second chamber, and a second discharge pipe through which the molten glass can be discharged from the surface of the molten glass in the second chamber ,
The upper side of the first stirring tank is connected to the upper side of the second stirring tank by a connecting pipe,
Wherein the molten glass is transferred from the first stirring tank to the second stirring tank through the connecting pipe. And a stirring portion for stirring the molten glass obtained in the molten portion, wherein the molten glass is a molten glass obtained by melting a glass raw material to obtain molten glass,
Wherein the stirring portion has a stirring tank and an agitator disposed inside the stirring tank,
The stirring device stirs the molten glass guided from the upper side downward or from the lower side to the inside of the stirring tank,
Wherein the agitator has a rotating shaft disposed along the vertical direction and a stirring blade which is fixed to the outer peripheral surface of the rotating shaft by being fitted to the rotating shaft and is arranged at a plurality of stages from the uppermost stage to the lowermost stage along the rotating shaft, The portion where the wing is fitted to the rotating shaft and the vicinity thereof are formed of reinforced platinum,
Wherein the rotary shaft has a hollow inside and is formed on an outer peripheral surface thereof and has a fitting hole into which a part of the stirring blade is fitted,
Wherein the stirring blade has a fitting protrusion that is fitted to the fitting hole of the rotating shaft and the fitting protrusion is fixed to the outer circumferential surface of the rotating shaft by being inserted into the fitting hole of the rotating shaft,
A manufacturing apparatus for a glass substrate. And a stirring portion for stirring the molten glass obtained in the molten portion, wherein the molten glass is a molten glass obtained by melting a glass raw material to obtain molten glass,
Wherein the stirring portion has a stirring tank and an agitator disposed inside the stirring tank,
The stirring device stirs the molten glass guided from the upper side downward or from the lower side to the inside of the stirring tank,
Wherein the agitator has a rotating shaft disposed along the vertical direction and a stirring blade which is fixed to the outer peripheral surface of the rotating shaft by being fitted to the rotating shaft and is arranged at a plurality of stages from the uppermost stage to the lowermost stage along the rotating shaft, The portion where the wing is fitted to the rotating shaft and the vicinity thereof are formed of reinforced platinum,
Wherein the rotary shaft has an internal cavity and is formed on an outer peripheral surface thereof and has a fitting hole for fitting the fitting projection of the wedge for fixing the rotary shaft and the stirring vane,
Wherein the stirring wing has a wedge through hole for allowing the wedge to pass therethrough and the wedge is passed through the wedge through hole and the fitting projection is fitted to the fitting hole so that the wedge is fixed to the outer peripheral surface of the rotating shaft In addition,
A manufacturing apparatus for a glass substrate. As a stirring apparatus for stirring the molten glass,
A stirring tank,
And a stirrer disposed inside the stirring tank,
The stirring device stirs the molten glass guided from the upper side downward or from the lower side to the inside of the stirring tank,
Wherein the agitator has a rotating shaft disposed along the vertical direction and a stirring blade which is fixed to the outer peripheral surface of the rotating shaft by being fitted to the rotating shaft and is arranged at a plurality of stages from the uppermost stage to the lowermost stage along the rotating shaft, The portion where the wing is fitted to the rotating shaft and the vicinity thereof are formed of reinforced platinum,
Wherein the rotary shaft has a hollow inside and is formed on an outer peripheral surface thereof and has a fitting hole into which a part of the stirring blade is fitted,
Wherein the stirring blade has a fitting protrusion that is fitted to the fitting hole of the rotating shaft and the fitting protrusion is fixed to the outer circumferential surface of the rotating shaft by being inserted into the fitting hole of the rotating shaft,
Stirring device. As a stirring apparatus for stirring the molten glass,
A stirring tank,
And a stirrer disposed inside the stirring tank,
The stirring device stirs the molten glass guided from the upper side downward or from the lower side to the inside of the stirring tank,
Wherein the agitator has a rotating shaft disposed along the vertical direction and a stirring blade which is fixed to the outer peripheral surface of the rotating shaft by being fitted to the rotating shaft and is arranged at a plurality of stages from the uppermost stage to the lowermost stage along the rotating shaft, The portion where the wing is fitted to the rotating shaft and the vicinity thereof are formed of reinforced platinum,
Wherein the rotary shaft has an internal cavity and is formed on an outer peripheral surface thereof and has a fitting hole for fitting the fitting projection of the wedge for fixing the rotary shaft and the stirring vane,
Wherein the stirring wing has a wedge through hole for allowing the wedge to pass therethrough and the wedge is passed through the wedge through hole and the fitting projection is fitted to the fitting hole so that the wedge is fixed to the outer peripheral surface of the rotating shaft In addition,
Stirring device.

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