JP5946206B2 - Glass substrate manufacturing method, glass substrate manufacturing apparatus, and stirring apparatus - Google Patents

Description

  The present invention relates to a glass substrate manufacturing method, a glass substrate manufacturing apparatus, and a stirring apparatus for manufacturing a glass substrate by molding a molten glass produced by melting a glass raw material.

Generally, a glass substrate is produced through a process of forming molten glass from a glass raw material and then forming the molten glass into a glass substrate.
In the glass manufacturing process described above, inhomogeneous molten glass causes striae and streaks that occur in glass products such as glass substrates. Therefore, it is important to stir the molten glass in order to improve such glass heterogeneity. In general, a stirring device for stirring molten glass includes a stirring tank, a lid (cover) that covers an upper part of the stirring tank, and a stirrer disposed inside the stirring tank. The stirrer has a shaft that is rotated by a motor or the like, and a stirring blade that is attached to the outer peripheral surface of the shaft by welding. The shaft passes through a part of the lid. Such a stirring device is a mechanism in which the stirring blade attached to the shaft stirs and mixes the molten glass when the molten glass passes through the inside of the stirring tank from the top to the bottom or from the bottom to the top. By stirring the molten glass in this manner, defects such as striae and stripes of the glass product are prevented.

  By the way, in order to mass-produce high-quality glass substrates from high-temperature molten glass, consideration should be given so that foreign substances that cause defects in the glass substrate do not enter the molten glass from any apparatus that manufactures the glass substrate. Is desired. For this reason, the inner wall of the member in contact with the molten glass in the manufacturing process of the glass substrate needs to be made of an appropriate material according to the temperature of the molten glass in contact with the member, the required quality of the glass substrate, and the like. For example, a platinum group metal such as platinum or a platinum alloy is usually used for materials such as a stirring tank and a stirrer constituting the above-described stirring device.

Although the temperature which heats a stirring apparatus (stirring tank) at the time of a stirring process changes with compositions of the glass substrate which should be shape | molded, it may exceed 1400 degreeC.
When the above-mentioned molten glass is passed through the stirrer and stirred, the liquid level rises and falls, so that there is a gas space of a certain width between the lid of the stirring tank and the liquid level of the molten glass. is necessary.

  The gas phase space in the agitation tank contains oxygen, and since the agitation tank is heated at a high temperature, platinum or a platinum alloy in contact with the gas phase space volatilizes. Since the gas phase space is at a higher temperature than the atmosphere outside the stirrer, the gas containing platinum or platinum alloy volatiles passes, for example, through a gap or the like existing between the stirrer shaft and the stirrer lid. There is a tendency to flow upward at lower temperatures.

Since the temperature of the stirrer shaft decreases as the distance from the upper surface (liquid level) of the molten glass in the stirrer increases, the temperature of the stirrer lid and the stirrer shaft is higher than the dew point of the volatiles. When it is low, volatile substances such as platinum contained in the atmosphere of the stirring device may condense on the surface of the lid or the shaft.
Condensed platinum and other volatiles may fall from the gap between the stirrer shaft and the stirrer tank lid and mix with the molten glass in the stirrer tank, leading to a decrease in the quality of the glass substrate. there were.

  In order to solve the above-mentioned problem, a method is known in which the surface defining the opening of the lid of the stirring vessel (stirring vessel) is heated to reduce volatiles condensed on the lid (Patent Document 1). In addition, a method of providing a receiving portion for receiving particles or foreign matters falling from above is known (Patent Document 2, Patent Document 3).

JP 2012-41264 A JP 2002-253942 A JP 2010-126432 A

  However, the method for heating the opening defining surface of the lid disclosed in Patent Document 1 detects the temperature in the annular gap between the heating means (heating element) and the shaft of the stirrer and the lid of the stirring tank. And means for controlling the magnitude of the current supplied to the heating means using the temperature detected by the detection means (thermocouple) and adjusting the temperature of the aperture defining surface, The device configuration becomes complicated. Moreover, as a method of heating the stirring tank, a method of directly heating the stirring tank, a method of covering the periphery of the stirring tank with refractory bricks, and heating an atmosphere (heating space) outside the refractory bricks to a high temperature state (hereinafter referred to as the heating tank) In the case of the latter indirect heating method, since the lid of the stirring tank is also in a high temperature state, volatiles are not condensed in the lid. However, the technical significance of applying the method disclosed in Patent Document 1 is low.

  Moreover, the method of providing the collar part (receiving part) which receives the foreign material falling from the upper direction disclosed by the said patent document 2 installs a collar part in the gaseous-phase space between the lid | cover of a stirring tank and the liquid level of molten glass. Therefore, it is inevitably necessary to enlarge the gas phase space, but if the gas phase space is large, the area of the platinum member in contact with the gas phase space becomes large. However, since the volatilization of platinum is promoted as the area of the platinum member in contact with the gas phase space is increased, increasing the gas phase space to install the collar portion promotes the volatilization of platinum. Increases the amount of volatiles that condense. Moreover, since the said collar part exists in the position near the upper surface of the molten glass in a stirring tank, in order to prevent the foreign material received by the collar part from falling and mixing with molten glass, the foreign material caught by the collar part There is also a problem that a discharging means for discharging the gas to the outside of the stirring device is required, and the apparatus configuration becomes complicated.

  Moreover, since the receiving part which receives the particle | grains which fall from the upper direction disclosed by the said patent document 3 is installed so that the bottom part may contact with the upper surface of molten glass, the contamination by melting of the material which comprises a receiving part is carried out. Concerned. Furthermore, there is a problem that particles (volatiles) received by the receiving portion are likely to be mixed into the molten glass from the gap between the inner wall of the stirring chamber.

  The present invention has been made to solve the above-mentioned various problems of the related art, and its object is to suppress the condensation of volatilized platinum in a stirring tank with a simple configuration, and to To provide a glass substrate manufacturing method, a glass substrate manufacturing apparatus, and a stirring device capable of preventing volatiles such as platinum condensed above from being mixed into molten glass in the stirring device.

  The present inventor suppresses the condensation of the volatilized platinum in the stirring tank with a simple configuration, and further prevents the volatiles such as platinum condensed above the stirring device from mixing into the molten glass in the stirring device. In order to prevent this, the inventors have come up with an invention having the following configuration.

(Invention of Configuration 1)
A glass substrate is formed from the melting step of melting a glass raw material to obtain a molten glass, the stirring step of stirring the molten glass obtained in the melting step with a stirrer, and the molten glass stirred in the stirring step Forming the glass substrate, wherein the stirring device comprises a stirring tank, a lid covering the top of the stirring tank, and a stirrer disposed inside the stirring tank, The stirrer has a rotating shaft arranged in a vertical direction and a stirring blade attached to a side peripheral surface of the rotating shaft, and the periphery of the stirring tank and the lid covering the upper part of the stirring tank is covered with a refractory material. A heating means for heating the atmosphere outside the refractory material, and the upper part of the rotary shaft passes through the lid and the refractory material thereon and is connected to a rotary drive means, The lid and above There is a gap between the refractory material, and in the stirring step, the molten glass is provided with a gas phase space between the liquid surface of the molten glass and a lid that covers the top of the stirring tank. Thus, the gas containing platinum volatiles, which are stirred by the stirrer and volatilized in the gas phase space while being guided from the top to the bottom or from the bottom to the top inside the stirring tank, passes through the gap. The temperature is low and flows upwardly and adheres to and adheres to the rotating shaft as platinum foreign matter, and the rotating shaft positioned above the refractory material through which the rotating shaft passes, between the rotating shaft and the lid and the refractory material. A flap having a size that substantially covers the existing gap is provided, and platinum foreign matter generated above the stirring device is prevented from entering the molten glass in the stirring tank. A process for producing a glass substrate that.

(Configuration 2)
The atmosphere heated by the heating means is further covered with a second refractory material, and the upper part of the rotating shaft further penetrates the second refractory material, and the rotating shaft and the second refractory material A second gap is provided between the gas containing platinum volatiles volatilized in the gas phase space through the gap between the rotary shaft and the lid and the refractory material thereon. Flows upward, and further flows through the second gap between the rotating shaft and the second refractory material, and flows upward at a lower temperature, and during this time, it is condensed and adhered to the rotating shaft as a platinum foreign matter. It is a manufacturing method of the glass substrate of the structure 1 characterized by these.

(Configuration 3)
A melting part for melting a glass raw material to obtain a molten glass, a stirring part for stirring the molten glass obtained in the melting part, and a molding part for forming a glass substrate from the molten glass stirred in the stirring part; The stirrer includes a stirrer, a lid that covers the top of the stirrer, and a stirrer disposed inside the stirrer, the stirrer being a vertical A rotating shaft arranged in a direction, and a stirring blade attached to a side peripheral surface of the rotating shaft, and the periphery of the stirring tank and a lid covering the upper part of the stirring tank is covered with a refractory material, and the fire resistance Heating means for heating the atmosphere outside the material, and the upper part of the rotary shaft passes through the lid and the refractory material thereon and is connected to the rotary drive means, the rotary shaft, the lid and Between the refractory material on it, between The stirrer is provided with a gas phase space between the liquid surface of the molten glass and a lid covering the upper part of the stirring tank, or the inside of the stirring tank from above to below, or The molten glass guided from below to above is agitated, and the rotary shaft positioned above the refractory material through which the rotary shaft passes substantially has a gap existing between the rotary shaft, the lid and the refractory material. A flap having a size to cover is provided, and a gas containing platinum volatiles volatilized in the gas phase space flows through the gap to a lower temperature and condenses and adheres to the rotating shaft as platinum foreign matter. Is an apparatus for manufacturing a glass substrate, which prevents the molten glass from being mixed into the molten glass in the stirring tank.

(Configuration 4)
A stirrer used in a stirring step of stirring molten glass obtained by melting glass raw material, wherein the stirrer includes a stirrer tank, a lid covering the upper part of the stirrer tank, and an inside of the stirrer tank A stirrer that is disposed in a vertical direction, and a stirrer that is attached to a side peripheral surface of the rotating shaft, and the stirrer is a liquid level of the molten glass. And a lid covering the upper part of the stirring tank, a gas phase space is provided to stir the molten glass guided from above to below or from below to above the stirring tank, and the stirring tank And the periphery of the lid covering the upper part of the agitation tank is covered with a refractory material, and has heating means for heating the atmosphere outside the refractory material, and above the rotating shaft, the lid and the refractory material thereon are provided. Penetrates and is connected to the rotational drive means, A gap is provided between the rotary shaft and the lid and the refractory material on the lid, and the rotary shaft and the rotary shaft positioned above the refractory material through which the rotary shaft passes, A flap having a size substantially covering the gap existing between the lid and the refractory material is provided, and the gas containing platinum volatiles volatilized in the gas phase space flows upward through the gap and has a lower temperature. It is a stirrer characterized in that it condenses and adheres as a platinum foreign matter to the rotating shaft and prevents the platinum foreign matter from being mixed into the molten glass in the stirring tank.

  According to the present invention, in the stirring step of stirring the molten glass obtained in the melting step with a stirring device, an indirect heating method is applied and the rotating shaft positioned above the refractory material through which the rotating shaft passes is rotated. By providing a flap having a size that almost covers the gap existing between the shaft, the lid, and the refractory material, it is possible to suppress condensation of volatilized platinum in the stirring tank with a simple configuration, and It is possible to provide a glass substrate manufacturing method, a glass substrate manufacturing apparatus, and a stirring device that can prevent volatiles such as platinum condensed above from being mixed into the molten glass in the stirring device.

It is a figure which shows an example of the flow of the manufacturing method of the glass substrate of this invention. It is a figure which shows typically an example of the apparatus which performs the melting process thru | or cutting process in this invention. It is a longitudinal cross-sectional view which shows one Embodiment of the stirring apparatus in this invention.

Hereinafter, embodiments of the present invention will be described in detail.
(Overall overview of glass substrate manufacturing method)
FIG. 1 is a diagram showing a flow of a glass substrate manufacturing method according to an embodiment of the present invention.
The glass substrate manufacturing method includes a melting step (ST1), a clarification step (ST2), a homogenization step (ST3), a supply step (ST4), a forming step (ST5), a cooling step (ST6), Cutting step (ST7). Moreover, the manufacturing method of a glass substrate has other processes, such as a grinding process, a grinding | polishing process, a washing | cleaning process, an inspection process, and a packing process. The plurality of glass plates stacked in the packing process are transported to a supplier (customer) as a delivery destination.

  FIG. 2 is a diagram schematically showing an apparatus for performing the melting step (ST1) to the cutting step (ST7). As shown in FIG. 2, the apparatus mainly includes a melting apparatus 100, a forming apparatus 200, and a cutting apparatus 300. The melting apparatus 100 includes a melting tank 101, a clarification tank 102, a stirring tank 103, a first pipe 104, a second pipe 105, and a third pipe 106. The stirring device including the stirring tank 103 will be described later.

In the melting step (ST1), molten glass MG is obtained by melting the glass raw material supplied into the melting tank 101 by heating with a flame and an electric heater (not shown). The clarification step (ST2) is performed in the clarification tank 102, and oxygen contained in the molten glass MG is heated by heating the molten glass MG in the clarification tank 102 supplied from the melting tank 101 through the first pipe 104. And SO ₂ bubbles are absorbed by O ₂ released by the oxidation-reduction reaction of the clarifying agent and grow and float on the liquid surface, or gas components in the bubbles are absorbed into the molten glass MG. The bubbles disappear.

In the homogenization step (ST3), the glass component MG is homogenized by stirring the molten glass MG in the stirring tank 103 supplied from the clarification tank 102 through the second pipe 105 using the stirrer 107.
In the supply step (ST4), the molten glass MG is supplied from the stirring vessel 103 to the molding apparatus 200 through the third pipe 106.

In the molding apparatus 200, a molding process (ST5) and a cooling process (ST6) are performed.
In the forming step (ST5), the molten glass MG is formed into a sheet glass SG to make a flow of the sheet glass SG. For example, an overflow down draw method using the molded body 210 is used. In this case, the flow direction of the sheet glass SG is vertically downward. In the cooling step (ST6), the sheet glass SG that is formed and flows has a desired thickness, and is cooled so that warpage and distortion due to cooling do not occur.

In the cutting step (ST7), the sheet glass SG supplied from the forming apparatus 200 is cut into a predetermined length in the cutting apparatus 300, thereby obtaining a plate-shaped glass substrate.
After this, after the end surface of the glass substrate is ground and polished, the glass substrate is cleaned, and further, the presence or absence of abnormal defects such as bubbles and striae is inspected. Packaged as a final product.

  The glass substrate produced in the present embodiment is suitably used for, for example, a glass substrate for liquid crystal display, a glass substrate for organic EL display, and a cover glass. In addition, the glass substrate can also be used as a display for a portable terminal device, a cover glass for a housing, a touch panel plate, a glass substrate for a solar cell, or a cover glass. Particularly, it is suitable for a glass substrate for a liquid crystal display using a polysilicon TFT.

Moreover, the thickness of a glass substrate is 0.1 mm-1.5 mm, for example. Preferably it is 0.1-1.2 mm, More preferably, it is 0.3-1.0 mm, More preferably, it is 0.3-0.8 mm, Most preferably, it is 0.3-0.5 mm.
Furthermore, the length of the glass substrate in the width direction is, for example, 500 mm to 3500 mm, preferably 1000 mm to 3500 mm, and more preferably 2000 mm to 3500 mm. On the other hand, the length of the glass substrate in the vertical direction is, for example, 500 mm to 3500 mm, preferably 1000 mm to 3500 mm, and more preferably 2000 mm to 3500 mm.

(Composition of glass substrate)
As the glass used for the glass substrate, for example, borosilicate glass, aluminosilicate glass, aluminoborosilicate glass, soda lime glass, alkali silicate glass, alkali aluminosilicate glass, and alkali aluminogermanate glass can be applied. The glass applicable to the present invention is not limited to the above.

The glass composition of a glass substrate can mention the following, for example. The content rate display of the composition shown below is mass%.
SiO ₂ : 50 to 70%,
Al ₂ O ₃ : 0 to 25%,
B ₂ O ₃ : 1 to 15%
MgO: 0 to 10%,
CaO: 0 to 20%,
SrO: 0 to 20%,
BaO: 0 to 10%,
RO: 5 to 30% (where R is the total amount of Mg, Ca, Sr and Ba),
It is preferable that it is an alkali free glass containing.

In addition, although it was set as the alkali free glass in said glass composition example, the glass substrate may be the alkali trace amount containing glass containing a trace amount of alkali metals. When an alkali metal is contained, the total of R ′ ₂ O is 0.10% or more and 0.5% or less, preferably 0.20% or more and 0.5% or less (where R ′ is selected from Li, Na, and K) It is preferable that the glass substrate G contains at least one kind. Of course, the total of R ′ ₂ O may be less than 0.10%. In order to facilitate melting of the glass, the content of iron oxide in the glass is 0.01 to 0.2% (preferably 0.01 to 0.08%) from the viewpoint of reducing the specific resistance. More preferably. Moreover, it is more preferable that the content of tin oxide added as a fining agent is 0.01 to 1% (preferably 0.01 to 0.5%).

(Description of Embodiment of the Present Invention)
The present invention includes a melting step (described above melting step) for melting a glass raw material to obtain molten glass, and a stirring step (described above homogenization step) in which the molten glass obtained in the melting step is stirred with a stirring device. And a forming step of forming a glass substrate from the molten glass stirred in the stirring step.

FIG. 3 is a longitudinal sectional view showing an embodiment of the stirring device in the present invention.
The stirring device 120 includes a stirring tank 103, a lid 110 that covers the top of the stirring tank 103, and a stirrer 107 disposed inside the stirring tank 103. The stirrer 107 includes a rotating shaft 108 arranged in a vertical direction, and a stirring blade 109 attached to a side peripheral surface below the rotating shaft 108. As described above, the second pipe 105 and the third pipe 106 are connected to the stirring tank 103, and the molten glass MG supplied from the clarification tank 102 through the second pipe 105 into the stirring tank 103 is The glass components are homogenized by stirring using the stirrer 107, and the homogenized molten glass MG is supplied from the stirring tank 103 to the molding apparatus 200 through the third pipe 106.
In FIG. 2 described above, only the agitation tank 103 and the agitator 107 are shown, but the detailed configuration is as shown in FIG.

  The periphery of the stirring tank 103 and the lid 110 covering the top of the stirring tank 103 is covered with a first refractory material 111. And it has a heating means (not shown) which heats the atmosphere (heating space 112) outside the first refractory material 111. That is, in the present invention, an indirect heating method is adopted as a method of heating the stirring vessel 103. The heating space 112 heated by the heating means is further covered with a second refractory material 113. The first refractory material 111 and the second refractory material 113 are refractories such as refractory bricks, refractory heat insulating bricks, or fiber heat insulating materials.

  Further, the upper part of the rotating shaft 108 penetrates the lid 110 and the first refractory material 111 thereon, and further penetrates the second refractory material 113 and is connected to a rotation driving means (not shown). Has been. A first gap 115 is provided between the rotary shaft 108 and the lid 110 and the first refractory material 111 thereon, and the rotary shaft 108 and the second refractory material. A second gap 116 is provided between the material 113.

The rotary shaft 108 positioned above the first refractory material 111 through which the rotary shaft 108 passes is provided between the rotary shaft 108, the lid 110, and the first refractory material 111. A flap 117 having a size that almost covers the gap 115 is provided. In the present embodiment, the flap 117 is provided on the rotating shaft 108 located in the heating space 112 above the first refractory material 111.
In addition, although platinum group metals, such as platinum or a platinum alloy, are used for materials, such as the stirring tank 103 and the stirrer 107 (rotary shaft 108, stirring blade 109) which comprise said stirring apparatus 120, also about the said flap 117, too. It is preferable to use the same platinum group metal.

  In the stirring process using the stirring device 120 described above, the molten glass MG supplied from the clarification tank 102 to the stirring tank 103 through the second pipe 105 is guided from above to below in the stirring tank 103. The molten glass MG that has been stirred by the stirrer 107 and whose glass components are homogenized is supplied from the stirring vessel 103 to the molding apparatus 200 through the third pipe 106. In addition, when the molten glass MG is passed through the stirring device 120 and stirred, the position of the liquid level slightly rises and falls, so the gap between the lid 110 that covers the upper part of the stirring tank 103 and the liquid level of the molten glass MG. The positional relationship between the agitation tank 103 and the pipe 105 is adjusted so as to have a gas phase space 114 having a certain width. Moreover, in this Embodiment, although the molten glass MG supplied in the stirring tank 103 is comprised so that the inside of the stirring tank 103 may be guide | induced from upper direction to the downward direction, it is not restricted to this, The interior may be configured to be guided from below to above.

  In such a stirring step, as described above, when the molten glass MG is passed and stirred, the liquid level rises and falls, so that a certain width is provided between the lid 110 of the stirring tank 103 and the liquid level of the molten glass MG. The gas phase space 114 contains oxygen, and since the agitation tank 103 is heated at a high temperature, platinum or a platinum alloy or the like in contact with the gas phase space 114 is provided. (Material of stirring tank 103 and stirrer 107) volatilizes. The gas containing platinum volatiles volatilized in the gas phase space 114 flows upward through a gap 115 existing between the rotating shaft 108 of the stirrer 107 and the lid 110 of the stirring tank 103.

  In the present embodiment, an indirect heating method is employed in which the atmosphere outside the first refractory material 111 (heating space 112) covering the stirring tank 103 and the lid 110 of the stirring tank 103 is heated. There is almost no atmospheric temperature difference in the gas phase space 114. Therefore, platinum volatiles do not condense and adhere to the lower surface of the lid 110 of the stirring vessel 103 in contact with the gas phase space 114, the inner wall of the stirring vessel 103, and the like. Further, the volatilization of platinum or the like is promoted as the contact area between the gas phase space 114 and the platinum member increases, but in this embodiment, there is no inconvenience above and below the liquid level of the molten glass MG in the stirring vessel 103. Since it is sufficient to provide a gas phase space of a degree, the gas phase space 114 can be reduced to the minimum necessary, and volatilization itself of platinum or the like can be reduced.

The gas containing platinum volatiles flowing into the upper heating space 112 through the gap 115 further flows upward through the gap 116 existing between the rotary shaft 108 and the second refractory material 113. . As described above, since the heating space 112 is heated, the atmospheric temperature does not decrease in the heating space 112, and the platinum volatiles are not easily condensed. In the process of flowing upwards through, the ambient temperature decreases, for example, when the temperature of the rotating shaft 108 of the stirrer 107 and the inner wall of the gap 116 at a position where the temperature decreases is lower than the dew point of the volatile matter Volatile substances such as platinum contained in the atmosphere condense and adhere to the surfaces of the inner surfaces of the rotating shaft 108 and the gap 116. It deposits when the vapor pressure of platinum exceeds the saturated vapor pressure.
Here, a specific example is given. In the stirring step, for example, when the atmospheric temperature of the heating space 112 is heated to about 1250 ° C. to 1480 ° C., the glass temperature of the molten glass MG in the stirring layer 103 at this time is about 1400 ° C. to 1500 ° C. At this time, it was confirmed that platinum volatiles were condensed and adhered to the surface of the rotating shaft 108 in the vicinity of the upper outlet of the gap 116 in the stirring device of FIG.
In this way, volatiles such as platinum condensing and adhering to the surfaces of the rotary shaft 108 and the inner wall of the gap 116 may fall into the heating space 112 from the gap 116 or the like.

  In the present embodiment, as described above, the rotary shaft 108 positioned in the heating space 112 above the first refractory material 111 includes the rotary shaft 108, the lid 110, and the first refractory material 111. Since the flap 117 having a size that substantially covers the first gap 115 existing therebetween is provided, even if condensed platinum volatiles fall into the heating space 112 from the gap 116 or the like, the flap 117 is placed on the flap 117. Fall. Therefore, this platinum volatile substance further drops from the gap 115 existing between the rotary shaft 108, the first refractory material 111 and the lid 110 of the stirring tank 103, and enters the molten glass MG in the stirring tank 103. Problems can be prevented.

  As described above, according to the embodiment of the present invention, in the stirring step of stirring the molten glass with the stirring device, condensation in the stirring tank of volatilized platinum or the like can be suppressed and the condensation is performed above the stirring device. Thus, it is possible to prevent the volatile matter such as platinum from being mixed into the molten glass in the stirring device, and it is possible to achieve these effects with a simple configuration.

  As mentioned above, although the manufacturing method of the glass substrate of this invention, the manufacturing apparatus of the glass substrate, and the stirring apparatus were demonstrated in detail, this invention is not limited to the said embodiment, In the range which does not deviate from the main point of this invention, it is various. Of course, improvements and changes may be made.

DESCRIPTION OF SYMBOLS 100 Melting apparatus 101 Melting tank 102 Clarification tank 103 Agitation tank 104 1st piping 105 2nd piping 106 3rd piping 107 Stirrer 108 Rotating shaft 109 Stirring blade 110 Lid 111 1st refractory material 112 Heating space 113 2nd refractory material 114 Gas phase space 115, 116 Gap 117 Flap 120 Stirrer 200 Molding device 210 Molded body 300 Cutting device

Claims (3)

A glass substrate is formed from the melting step of melting a glass raw material to obtain a molten glass, the stirring step of stirring the molten glass obtained in the melting step with a stirrer, and the molten glass stirred in the stirring step A glass substrate manufacturing method comprising:
The stirrer includes a stirrer, a lid that covers the top of the stirrer, and a stirrer disposed inside the stirrer, and the stirrer includes a rotating shaft that is disposed in a vertical direction, and the rotating shaft. And the stirring vessel, the lid, the rotating shaft, and the stirring blade are all made of a platinum group metal, and the periphery of the lid that covers the stirring vessel and the upper part of the stirring vessel. is covered with a first refractory material, a heating means for heating the outer atmosphere of said first refractory material, above the rotating shaft penetrates the lid and the first refractory material thereon A first gap is provided between the rotary shaft and the lid and the first refractory material on the lid.
The atmosphere heated by the heating means is further covered with a second refractory material, and the upper part of the rotating shaft further penetrates the second refractory material, and the rotating shaft and the second refractory material A second gap is provided between the second refractory material and the rotating shaft in the atmosphere by the heating means,
In the stirring step, the molten glass is provided with a gas phase space between the liquid surface of the molten glass and a lid covering the upper portion of the stirring tank, and the inside of the stirring tank is moved from above to below, or While being guided from below to above, it is stirred by the agitator,
A gas containing platinum volatiles volatilized in the gas phase space flows upward through a first gap between the rotating shaft and the lid and the first refractory material thereon, and further, Through the second gap between the rotating shaft and the second refractory material, it flows upward at a lower temperature, and during this time, it adheres and adheres to the rotating shaft as platinum foreign matter,
At the temperature position where the vapor pressure of the gas containing platinum volatiles does not exceed the saturated vapor pressure , the rotary shaft, the lid, and the rotary shaft located above the first refractory material through which the rotary shaft penetrates A flap having a size that substantially covers the first gap existing between the first refractory material is provided, and platinum foreign matter generated above the stirrer is prevented from entering the molten glass in the stirrer. A method for producing a glass substrate, comprising: A melting part for melting a glass raw material to obtain a molten glass, a stirring part for stirring the molten glass obtained in the melting part, and a molding part for forming a glass substrate from the molten glass stirred in the stirring part; A glass substrate manufacturing apparatus comprising:
The agitation unit includes an agitation tank, a lid that covers the upper part of the agitation tank, and an agitator that is disposed inside the agitation tank, the agitator including a rotating shaft that is disposed in a vertical direction, and the rotating shaft. And the stirring vessel, the lid, the rotating shaft, and the stirring blade are all made of a platinum group metal, and the periphery of the lid that covers the stirring vessel and the upper part of the stirring vessel. is covered with a first refractory material, a heating means for heating the outer atmosphere of said first refractory material, above the rotating shaft penetrates the lid and the first refractory material thereon A first gap is provided between the rotary shaft and the lid and the first refractory material on the lid.
The atmosphere heated by the heating means is further covered with a second refractory material, and the upper part of the rotating shaft further penetrates the second refractory material, and the rotating shaft and the second refractory material A second gap is provided between the second refractory material and the rotating shaft in the atmosphere by the heating means,
The stirrer is provided with a gas phase space between the liquid surface of the molten glass and a lid covering the upper part of the stirring tank, and the inside of the stirring tank is guided from above to below or from below to above. Stirring the molten glass,
At the temperature position where the vapor pressure of the gas containing platinum volatiles does not exceed the saturated vapor pressure , the rotary shaft, the lid, and the rotary shaft located above the first refractory material through which the rotary shaft penetrates Providing a flap having a size that substantially covers the first gap existing between the first refractory material;
A gas containing platinum volatiles volatilized in the gas phase space flows upward through a first gap between the rotating shaft and the lid and the first refractory material thereon, and further, Through the second gap between the rotating shaft and the second refractory material, the temperature flows upward at a lower temperature, and during this time, the rotating shaft is condensed and adhered as platinum foreign matter, and the platinum foreign matter is in the stirring tank. An apparatus for producing a glass substrate, characterized in that the glass substrate is prevented from being mixed into the molten glass. A stirring device used in a stirring process for stirring molten glass obtained by melting a glass raw material,
The stirrer includes a stirrer, a lid that covers the top of the stirrer, and a stirrer disposed inside the stirrer, and the stirrer includes a rotating shaft that is disposed in a vertical direction, and the rotating shaft. And the stirring vessel, the lid, the rotating shaft, and the stirring blade are all made of a platinum group metal.
The stirrer is provided with a gas phase space between the liquid surface of the molten glass and a lid covering the upper part of the stirring tank, and the inside of the stirring tank is guided from above to below or from below to above. Stirring the molten glass,
Around the lid covering the upper portion of the agitation vessel and the agitation tank is covered with a first refractory material, a heating means for heating the outer atmosphere of said first refractory material,
The upper part of the rotating shaft passes through the lid and the first refractory material thereon and is connected to a rotation driving means. Between the rotating shaft and the lid and the first refractory material thereon. Is provided with a first gap,
The atmosphere heated by the heating means is further covered with a second refractory material, and the upper part of the rotating shaft further penetrates the second refractory material, and the rotating shaft and the second refractory material A second gap is provided between the second refractory material and the rotating shaft in the atmosphere by the heating means,
At the temperature position where the vapor pressure of the gas containing platinum volatiles does not exceed the saturated vapor pressure , the rotary shaft, the lid, and the rotary shaft located above the first refractory material through which the rotary shaft penetrates Providing a flap having a size that substantially covers the first gap existing between the first refractory material;
A gas containing platinum volatiles volatilized in the gas phase space flows upward through a first gap between the rotating shaft and the lid and the first refractory material thereon, and further, Through the second gap between the rotating shaft and the second refractory material, the temperature flows upward at a lower temperature, and during this time, the rotating shaft is condensed and adhered as platinum foreign matter, and the platinum foreign matter is in the stirring tank. A stirrer characterized by preventing mixing in the molten glass.

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