WO2014050826A1

WO2014050826A1 - Glass-melting method, process for manufacturing glass substrate and glass-melting apparatus

Info

Publication number: WO2014050826A1
Application number: PCT/JP2013/075734
Authority: WO
Inventors: 正恭松林; 英明染井
Original assignee: ＡｖａｎＳｔｒａｔｅ株式会社
Priority date: 2012-09-28
Filing date: 2013-09-24
Publication date: 2014-04-03
Also published as: JPWO2014050826A1; CN103917498B; CN106007340B; CN106007340A; JP5706544B2; JP2015155369A; JP5941175B2; CN103917498A

Abstract

Provided are: a glass-melting method by which the increase in frictional resistance between an electrode and a through hole of a melting vessel in thrusting the electrode through the through hole is suppressed to enable stable and long-term melting of glass in the melting vessel; a process for manufacturing a glass substrate; and a glass-melting apparatus. This glass-melting method includes: a measurement step for measuring, in subjecting an electrode which has shortened to pushing with a pressing member toward molten glass, the inclination of the rear end face of the electrode with respect to the central axis of a through hole; a deciding step for deciding, on the basis of the result obtained in the measurement step, the pressing direction in which the pressing member is to be pressed; and a pressing step for pressing the rear end face of the electrode with the pressing member in the pressing direction decided in the deciding step.

Description

Glass melting method, glass substrate manufacturing method, and glass melting apparatus

The present invention relates to a glass melting method, a glass substrate manufacturing method, and a glass melting apparatus.

For example, when manufacturing a glass substrate for a flat panel display (FPD), generally, a glass raw material put into a melting tank is melted to produce a molten glass. This molten glass is clarified by defoaming or the like, and then formed into a sheet-like glass by a forming apparatus. A glass substrate is obtained by cutting the sheet-like glass with a predetermined length.

When melting glass raw material to make molten glass, the glass raw material charged on the liquid surface of the molten glass is melted by a flame such as a burner. Specifically, the glass raw material starts to melt gradually by the heat radiation of the furnace wall heated by a burner or the like or a high-temperature gas phase atmosphere, and then melts in the molten glass below. On the other hand, the molten glass is stored in a melting tank and is energized using a pair of electrodes in contact with the molten glass. By this energization, the molten glass itself generates Joule heat, and this Joule heat heats the molten glass itself.

It is known to use a heat-resistant material such as platinum, a platinum rhodium alloy, molybdenum, or tin oxide as a material used for an electrode used in a dissolution tank (Patent Document 1).

JP 2003-292323 A

However, in the electrode using tin oxide or molybdenum, the tip portion in contact with the molten glass is worn away by erosion and becomes shorter with time. When the position of the tip of the electrode is retracted from a predetermined position due to erosion, a large amount of current flows through the wall of the dissolution tank, and the dissolution tank wall may be eroded. Therefore, when the electrode is eroded and the position of the tip of the electrode is retracted from a predetermined position, it is necessary to push the electrode toward the inside of the dissolution tank so that the tip of the electrode becomes a predetermined position.

The electrode is arranged in a through hole provided in the wall of the dissolution tank. If the frictional resistance between the electrode and the through-hole is large when pushing the electrode toward the inside of the dissolution tank, a force is applied to the wall of the dissolution tank, which may damage the wall of the dissolution tank.

Therefore, the present invention can reduce the frictional resistance between the electrode and the through-hole when the electrode is pushed into the through-hole of the melting tank, and can dissolve the glass stably over a long period of time using the melting tank. It aims at providing the melting method of glass, the manufacturing method of a glass substrate, and the melting apparatus of glass.

One embodiment of the present invention is a method for melting glass stored in a dissolution tank in which electrodes made of tin oxide are provided in at least a pair of through holes. This glass melting method includes a measurement step of measuring the inclination of the rear end face of the electrode with respect to the central axis of the through hole when the shortened electrode is pushed out by a pressing member in the molten glass direction; and the measurement obtained in the measurement step A determining step of determining a pressing direction of the pressing member based on the result; and a pressing step of pressing the rear end face of the electrode by the pressing member based on the pressing direction obtained in the determining step.
In the above aspect, it is preferable that the pressing direction is determined in the determining step so as to reduce the inclination of the rear end face.
Further, in the above aspect, in the pressing step, the rear end surface of the electrode is supported in a state where at least a part of the electrode protruding outside the dissolution tank is supported from a direction intersecting the central axis of the through hole. It is preferable to press.
Another aspect of the present invention is a method for producing a glass substrate including the glass melting method described above.
Further, another aspect of the present invention includes a melting tank in which electrodes made of tin oxide are provided in at least a pair of through holes; a pressing member that pushes the shortened electrode in the direction of molten glass; and a central axis of the through holes Measuring device for measuring the inclination of the rear end face of the electrode with respect to the glass melting device.

According to the above aspect, it is possible to reduce the frictional resistance between the electrode and the through hole when the electrode is pushed into the through hole of the melting tank, and to dissolve the glass stably over a long period of time using the melting tank. it can.

It is process drawing explaining the process of the manufacturing method of the glass of this embodiment. It is a figure which shows typically the apparatus which performs from the melt | dissolution process shown in FIG. 1 to a cutting process. It is a figure explaining the dissolution tank which performs the melt | dissolution process shown in FIG. It is sectional drawing of the electrode body vicinity in the xz plane of the xyz orthogonal coordinate system shown in FIG. It is sectional drawing of the electrode body vicinity in xy plane of the orthogonal coordinate system. It is the front enlarged view of the electrode body vicinity seen from the x direction of the orthogonal coordinate system. It is sectional drawing which shows the inclination of the electrode body in xz plane of the orthogonal coordinate system. It is sectional drawing which shows the inclination of the electrode body in xy plane of the orthogonal coordinate system.

Hereinafter, the manufacturing method of the glass of this embodiment is demonstrated. FIG. 1 is a process diagram illustrating the steps of the glass substrate manufacturing method of the present embodiment.
The glass substrate manufacturing method includes a melting step (ST1), a clarification step (ST2), a homogenization step (ST3), a supply step (ST4), a molding step (ST5), and a slow cooling step (ST6). And a cutting step (ST7). In addition, a plurality of glass plates that have a grinding process, a polishing process, a cleaning process, an inspection process, a packing process, and the like and are stacked in the packing process are conveyed to a supplier.

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 200, a molding apparatus 300, and a cutting apparatus 400. The dissolution apparatus 200 mainly has a dissolution tank 201, a clarification tank 202, a stirring tank 203, a first pipe 204, and a second pipe 205.

In the melting step (ST1), the glass raw material supplied into the melting tank 201 is heated and melted with a flame generated from the burner 206 (see FIG. 3), whereby the molten glass MG is made. Thereafter, the molten glass MG is energized and heated using the electrode body 208 (see FIG. 3).
The clarification step (ST2) is performed in the clarification tank 202. When the molten glass MG in the clarification tank 202 is heated, bubbles such as O ₂ contained in the molten glass MG grow by absorbing oxygen generated by the reductive reaction of the clarifier and float on the liquid surface. And released. Or gas components, such as oxygen in a bubble, are absorbed in molten glass for the oxidation reaction of a clarifying agent, and a bubble disappears.
In the homogenizing step (ST3), the molten glass MG in the stirring vessel 203 supplied through the first pipe 204 is stirred using a stirrer, so that the glass components are homogenized.
In the supplying step (ST4), the molten glass MG is supplied to the molding apparatus 300 through the second pipe 205.

In the molding apparatus 300, a molding process (ST5) and a slow cooling process (ST6) are performed.
In the forming step (ST5), the molten glass MG is formed into a sheet glass, and a flow of the sheet glass is created. In this embodiment, an overflow downdraw method is used. In the slow cooling step (ST6), the sheet-like glass that is formed and flowed is cooled to have a desired thickness, so that internal distortion does not occur and the thermal shrinkage rate does not increase.
In the cutting step (ST7), the cutting device 400 cuts the sheet-like glass supplied from the forming device 300 into a predetermined length, thereby obtaining a glass substrate. The cut glass substrate is further cut into a predetermined size to produce a glass substrate of a target size. Thereafter, the glass substrate is ground and polished, and then cleaned. Further, the glass substrate is inspected for abnormal defects such as bubbles and striae, and the glass substrate that has passed the inspection is packed as a final product. .

FIG. 3 is a diagram illustrating a melting tank 201 that performs a melting step.
The melting tank 201 has a wall 210 made of a refractory member that is a refractory brick. The dissolution tank 201 has an internal space surrounded by a wall 210. The internal space of the melting tank 201 is formed in a liquid tank B that accommodates the molten glass MG formed by melting the glass raw material introduced into the space while being heated, and an upper layer of the molten glass MG. And an upper space A which is a gas phase.
The wall 210 of the upper space A is provided with a burner 206 that emits a flame by burning combustion gas mixed with fuel and oxygen. The burner 206 heats the refractory member in the upper space A with a flame to raise the temperature of the wall 210. The glass raw material is heated and melted by the radiant heat of the wall 210 which has become high temperature and by the gas phase atmosphere which has become high temperature.

The

walls

210 and 210 facing the liquid tank B of the dissolution tank 201 are each provided with three through holes 210a. In the through hole 210a, three pairs of electrode bodies 208 made of a heat-resistant conductive material such as tin oxide or molybdenum are arranged. In the present embodiment, the electrode body 208 is made of tin oxide. All of the three pairs of electrode bodies 208 extend from the outside of the dissolution tank 201 toward the inner wall surface of the liquid tank B through the through holes 210a.

Of the three pairs of electrode bodies 208, the electrode bodies on the far side in the figure are not shown. Each pair of the three pairs of electrode bodies 208 is disposed in the through hole 210a so as to face each other through the molten glass MG. Each pair of electrode bodies 208 serves as a positive electrode and a negative electrode, and allows a current to flow through the molten glass MG between the electrodes. This energization generates Joule heat in the molten glass MG, and the molten glass MG is heated by the Joule heat generated by itself. In the melting tank 201, the molten glass MG is heated to, for example, 1500 ° C. or higher. The heated molten glass MG is sent to the clarification tank 202 through a glass supply pipe.

In this embodiment, the dissolution tank 201 is provided with three pairs of electrode bodies 208, but may be provided with one pair, two pairs, or four or more pairs of electrode bodies. That is, in this embodiment, the glass stored in the melting tank 201 is melted using the melting tank 201 in which the electrode body 208 is provided in each of at least the pair of through

holes

210a and 210a.

Hereinafter, description will be made using an xyz orthogonal coordinate system in which the vertical direction is the z-axis and the xy plane is a horizontal plane. As shown in FIG. 3, the opposing

walls

210 and 210 of the liquid tank B of the dissolution tank 201 are provided in parallel to the yz plane.
FIG. 4 is a cross-sectional view parallel to the xz plane in the vicinity of the electrode body 208 and the through hole 210a of the dissolution tank 201. FIG. 5 is a cross-sectional view parallel to the xy plane in the vicinity of the electrode body 208 and the through hole 210a. FIG. 6 is an enlarged front view of the vicinity of the electrode body 208 and the through hole 210a as seen from the x direction. In FIGS. 4 to 6, illustration of connectors and the like provided on the electrode body 208 is omitted.

The electrode body 208 is a composite body in which a plurality of long electrode body elements 208a are bundled so as to extend in one direction, and each of the electrode body elements 208a energizes the molten glass MG. The front end surface 208f and the rear end surface 208b of the electrode body 208 are configured to be perpendicular to the central axis C1 of the electrode body 208. 4 to 6, the electrode body element 208a is composed of a total of 16 electrode body elements 208a, with four rows in the vertical direction and four rows in the horizontal direction. The electrode body 208 as a composite body including the electrode body elements 208a is limited to a structure composed of a total of 16 electrode body elements 208a in four rows in the vertical direction and four rows in the horizontal direction as in this embodiment. The total number, the number of columns in the vertical direction, and the number of columns in the horizontal direction are not particularly limited. For example, the electrode body 208 may be composed of one electrode body element 208a.

As shown in FIGS. 4 and 5, the wall 210 of the melting tank 201 is configured by stacking refractory members that are refractory bricks. The wall 210 is provided with a through hole 210a. The central axis C1 of the through hole 210a and the wall surface of the through hole 210a are provided in parallel with the x axis. That is, the central axis C1 of the through hole 210a and the wall surface of the through hole 210a are provided perpendicular to the wall 210 parallel to the yz plane.

The electrode body 208 is inserted and installed in the through hole 210a. That is, the electrode body 208 extends toward the inner wall surface of the liquid tank B, and the refractory member around the electrode body 208 constituting the wall 210, specifically, the lower side, upper side, and It is held by a refractory member on the side. 4 and 5, the central axis C2 of the electrode body 208 coincides with the central axis C1 of the through hole 210a.

When the electrode body 208 is installed, the position of the front end surface 208f is aligned with the position P0 of the inner wall surface of the liquid tank B (the inner surface of the wall 210). That is, the front end surface 208f of the electrode body 208 and the inner wall surface of the dissolution tank 201 are adjacent to each other without a step. That is, the front end surface 208 f can be arranged on the same plane as the inner wall surface of the liquid tank B. The tip surface 208f of the electrode 208 may be disposed so as to protrude to the inside of the liquid tank B from the through hole 210a to some extent, but the position of the tip surface 208f is matched with the position P0 of the inner wall surface of the liquid tank B. Thus, erosion of the electrode body 208 and erosion of the refractory member constituting the wall 210 of the dissolution tank 201 can be reduced.

In the electrode body 208, the molten glass MG is energized and heated, so that the tip portion in contact with the molten glass MG is eroded and worn by the molten glass MG, and the position of the tip surface 208f is liquid as shown in FIGS. The tank B moves backward from the position P0 of the inner wall surface of the tank B to the outside of the dissolution tank 201. Thus, when the front end surface 208f of the electrode body 208 is recessed from the inner wall surface of the liquid tank B to the inside of the through hole 210a, not only the voltage between the opposing

electrode bodies

208 and 208 increases, but also the electrode body The wall 210 near 208 is easily eroded. Therefore, a pressing structure 220 for pressing the electrode body 208 in the direction of the molten glass MG is provided outside the melting tank 201.

The pressing structure (pressing member) 220 includes a horizontal jig 221 and a vertical jig 222 disposed on the rear end surface 208b of the electrode body 208, a worm jack 223 that applies a pressing force to the vertical jig 222, and a reference plane setting device. 224 and a measurement gauge 225.
As shown in FIG. 6, the horizontal jig 221 is stretched over all the electrode body elements 208a adjacent in the horizontal direction, and is provided in each stage from the uppermost stage to the lowermost stage of the electrode body element 208a. It has been. The vertical jig 222 is stretched over each horizontal jig 221 adjacent in the vertical direction.

4 and 5, the worm jack 223 includes a flange portion 223a, a pressing shaft 223b, and a drive portion 223c. The flange portion 223a is provided so as to be fixed at an arbitrary position of a frame-like structure (not shown) provided outside the melting tank 201, and the inclination of the surface facing the electrode body 208 can be adjusted by a bolt or the like. It has become. The pressing shaft 223b is provided perpendicular to the flange portion 223a, and a trapezoidal screw is formed on the outer peripheral surface. The drive unit 223c includes a worm gear having a gear. The gear is formed with a trapezoidal screw on the inner periphery and is screwed to the trapezoidal screw of the pressing shaft 223b. When a handle (not shown) is attached to the drive unit 223c and rotated, the gear of the worm gear rotates, and the pressing shaft 223b moves forward and backward in a direction perpendicular to the flange portion 223a by the action of the trapezoidal screw. The worm jack 223 moves the pressing shaft 223b forward in the negative direction of the x-axis with the tip of the pressing shaft 223b in contact with the vertical jig 222, so that the electrode is interposed via the vertical jig 222 and the horizontal jig 221. A pressing force is applied to the rear end surface 208b of the body 208. In this embodiment, one worm jack 223 is installed, but the number of installed worm jacks 223 may be two or more.

As shown in FIG. 4, the reference plane setting device 224 can use, for example, a commercially available laser marking device or laser level. The reference plane setting device 224 is configured to set a reference plane or a reference line in the surrounding space by irradiating laser light from the main body 224a along the vertical plane and the horizontal plane. In the present embodiment, as shown in FIG. 3, a vertical plane parallel to the wall 210 of the dissolution tank 201 and separated from the wall 210 by a predetermined distance D0 is set as the reference plane R. That is, the reference plane R is set in parallel with the yz plane. Further, the central axis C <b> 1 of the through hole 210 a provided in the wall 210 of the dissolution tank 201 and the wall surface of the through hole 210 a are provided perpendicular to the wall 210. Therefore, the reference plane R is perpendicular to the central axis C1 of the through hole 210a and the wall surface of the through hole 210a.
The measurement gauge (measuring instrument) 225 is a gauge capable of measuring the distance between two points, and measures the distance between an arbitrary point on the rear end surface 208b of the electrode body 208 and the reference plane R.

As shown in FIGS. 4 and 5, the electrode body 208 is inserted into the through hole 210 a provided in the wall 210 of the liquid tank B of the dissolution tank 201, and the rear end part is inserted into the dissolution tank 201 from the through hole 210 a. It is arranged in a state protruding from the outside. Below the rear end of the electrode body 208, there is provided an electrode support base 230 that supports at least a part of the electrode body 208 protruding outside the dissolution tank 201 from the z direction intersecting the central axis C1 of the through hole 210a. It has been.

As shown in FIGS. 4 and 6, the electrode support base 230 includes a pedestal part 231, an elevating part 232, an adjusting screw 233, an insulating part 234, and an electrode support part 235. The pedestal portion 231 supports the lifting / lowering portion 232 via the adjustment screw 233. The elevating unit 232 is configured to elevate in the vertical direction (z direction) by the adjusting screw 233. An insulating part 234 made of an insulator is disposed on the elevating part 232. On the insulating part 234, the electrode support part 235 which consists of a refractory brick is arrange | positioned. The electrode support base 230 supports the electrode body 208 so that the central axis C2 of the electrode body 208 is horizontal by raising and lowering the elevating part 232 with the adjusting screw 233 and setting the electrode support part 235 to an appropriate height. is doing.

Next, the operation of this embodiment will be described.
In the melting step (ST1) of the glass substrate manufacturing method shown in FIG. 1, after the electrode body 208 is disposed in the through hole 210a of the wall 210 of the liquid tank B of the melting tank 201, the glass raw material is supplied into the melting tank 201. Is done. The glass raw material is heated and melted by the flame generated by the burner 206, and the molten glass MG is stored in the liquid tank B. Thereafter, the molten glass MG is energized and heated using the electrode body 208. When the energization heating of the molten glass MG is continued for a long time, the tip of the electrode body 208 is eroded by the molten glass MG. As a result, as shown in FIGS. 4 and 5, the position of the distal end surface 208 f of the electrode body 208 retreats from the initial position P 0 to the inside of the through hole 210 a.

Thus, in the method of melting the glass stored in the melting tank 201 in which the electrode body 208 made of tin oxide is provided in at least a pair of the through holes 210a, the shortened electrode body 208 is used as the molten glass MG in the melting tank 201. A process of extruding in the direction is required. Hereinafter, the process of extruding the electrode body 208 in the molten glass MG direction in the melting tank 201 will be described.

7A and 7B are cross-sectional views parallel to the xz plane, where FIG. 7A is a cross-sectional view showing the periphery of the electrode body 208 before being pushed in, and FIG. 7B is a cross-sectional view showing the periphery of the electrode body 208 after being pushed in. 8A and 8B are cross-sectional views parallel to the xy plane, where FIG. 8A is a cross-sectional view showing the periphery of the electrode body 208 before being pushed in, and FIG. 8B is a cross-sectional view showing the periphery of the electrode body 208 after being pushed in. In FIG. 7, the electrode support 230 is not shown.
As shown in FIG. 7A, the electrode body 208 may have its center axis C2 inclined with respect to the center axis C1 of the through hole 210a in the vertical plane. Further, as shown in FIG. 8A, the electrode body 208 may have its central axis C2 inclined with respect to the central axis C1 of the through hole 210a in the horizontal plane.

In the present embodiment, the inclination of the central axis C2 of the electrode body 208 with respect to the central axis C1 of the through hole 210a in the xz plane (vertical plane) is defined as the vertical inclination, and the central axis of the through hole 210a in the xy plane (horizontal plane) The inclination of the central axis C2 of the electrode body 208 with respect to C1 is defined as the left-right inclination. In the xz plane shown in FIG. 7, when the inclination of the central axis C2 of the electrode body 208 is positive, the central axis C2 of the electrode body 208 is inclined upward with respect to the central axis C1 of the through hole 210a or the x axis. If the inclination of the central axis C2 of the electrode body 208 is negative, the central axis C2 of the electrode body 208 is inclined downward with respect to the central axis C1 of the through-hole 210a or the x-axis. In the xy plane shown in FIG. 8, when the inclination of the central axis C2 of the electrode body 208 is positive, the central axis C2 of the electrode body 208 is inclined to the right with respect to the central axis C1 of the through hole 210a or the x axis. In other words, when the inclination of the central axis C2 of the electrode body 208 is negative, the central axis C2 of the electrode body 208 is inclined to the left with respect to the central axis C1 or the x axis of the through hole 210a.

The factors that cause the central axis C2 of the electrode body 208 to incline with respect to the central axis C1 of the through hole 210a as described above are, for example, thermal expansion of the wall 210 due to the temperature rise of the dissolution tank 201, and the weight of the rear end of the electrode body 208. There are improper fixing of the flange portion 223a of the worm jack 223, warping of a structure (not shown) to which the flange portion 223a of the worm jack 223 is fixed, and the like.
When the electrode body 208 is pushed out in the direction of the molten glass MG without properly determining the pressing direction of the electrode body 208 in a state where the center axis C2 of the electrode body 208 is inclined with respect to the center axis C1 of the through hole 210a, the electrode A large frictional force is generated between the body 208 and the through hole 210a, and a large force is required to push the electrode body 208. If the electrode 208 is pushed into the through-hole 210a in such a state, the wall 210 of the liquid tank B of the dissolution tank 201 may be damaged by receiving a large force.

Therefore, in this embodiment, when the shortened electrode body 208 is pushed out by the pressing structure 220 in the direction of the molten glass MG in the melting tank 201, the inclination of the rear end surface 208b of the electrode body 208 with respect to the central axis C1 of the through hole 210a is set. The measurement process to measure is implemented.

Specifically, as shown in FIG. 7A, distances in the x direction between the reference plane R and the rear end surface 208b of the electrode body 208 are measured at a plurality of locations in the z direction. In this embodiment, the front end of the measurement gauge 225 is brought into contact with the rear end surface 208b of the electrode body 208, and the measurement gauge 225 is kept parallel to the x-axis using a leveler or a reference surface setting device 224. In this state, the distance in the x direction between the rear end surface 208b of the electrode body 208 and the reference surface R is read by reading the scale of the measurement gauge 225 irradiated with the laser beam indicating the reference surface R from the reference surface setting device 224. Measure. This is performed at a plurality of locations in the z direction, and the distances D1 and D2 in the x direction between the rear end surface 208b of the electrode body 208 and the reference surface R are measured, whereby the xz plane of the rear end surface 208b of the electrode body 208 is measured. The slope inside is determined. In addition, it is preferable that the measurement of the distance of the x direction between the rear end surface 208b of the electrode body 208 and the reference plane R is performed at three or more places.
Here, the rear end surface 208 b of the electrode body 208 is provided perpendicular to the central axis C <b> 2 of the electrode body 208. The central axis C1 of the through hole 210a is parallel to the x axis. Therefore, the inclination of the central axis C2 of the electrode body 208 in the xz plane is obtained from the inclination of the rear end surface 208b of the electrode body 208 in the xz plane, and further, the electrode body 208 with respect to the central axis C1 of the through hole 210a in the xz plane. The inclination of the central axis C2 is obtained.

Similarly, as shown in FIG. 8A, the distance in the x direction between the reference plane R and the rear end face 208b of the electrode body 208 is measured at a plurality of points in the y direction. In the present embodiment, for example, the distance D3 in the x direction between the rear end surface 208b of the electrode body 208 and the reference surface R is obtained by bringing the front end of the measurement gauge 225 into contact with the left end and the right end of the rear end surface 208b of the electrode body 208. , D4 is measured. Thereby, the inclination of the rear end face 208b of the electrode body 208 in the xy plane is obtained, and further, the inclination of the central axis C2 of the electrode body 208 with respect to the central axis C1 of the through hole 210a in the xy plane is obtained.

Thus, after measuring the inclination of the electrode body 208 with respect to the central axis C1 of the through-hole 210a, based on the measurement result obtained by the measurement process, the rear end surface 208b of the electrode body 208 by the pressing structure (pressing member) 220 is measured. A determination step for determining the pressing direction is performed. In the determination step, preferably, the pressing direction is determined so as to reduce the inclination of the rear end surface 208b of the electrode body 208. In the determination step, preferably, the pressing position of the rear end surface 208b is determined together with the pressing direction of the rear end surface 208b.

Specifically, as shown in FIG. 7A, the pressing direction of the rear end surface 208b of the electrode body 208 by the pressing structure 220 is determined. In the present embodiment, as in the case of measuring the inclination of the rear end surface 208b of the electrode body 208, as shown in FIGS. 7A and 8A, the flange portion 223a of the worm jack 223 and the reference surface R The distances d1, d2, d3, and d4 are measured at a plurality of locations in the z direction and the y direction by the measurement gauge 225, and the inclination of the flange portion 223a with respect to the reference plane R is obtained. In addition, it is preferable to measure the distance between the flange part 223a and the reference plane R at three or more places.
Next, the inclination of the flange portion 223a is adjusted by an adjustment screw (not shown) so that the flange portion 223a is parallel to the reference plane R. Thereby, the pressing direction of the rear end surface 208b of the electrode body 208 by the pressing shaft 223b of the worm jack 223 is made parallel to the x-axis. That is, the pressing direction of the rear end surface 208b of the electrode body 208 is parallel to the central axis C1 of the through hole 210a.

Moreover, you may determine a press position with the determination of a press direction as mentioned above. Alternatively, the pressing position can be determined without determining the pressing direction. The determination of the pressing position can be performed as follows. When the central axis C2 of the electrode body 208 is inclined downward with respect to the central axis C1 of the through hole 210a, the worm jack 223 is moved, and the pressing position of the rear end surface 208b of the electrode body 208 by the pressing shaft 223b is the center. It should be above the axis C2. Conversely, when the center axis C2 of the electrode body 208 is inclined upward with respect to the center axis C1 of the through hole 210a, the worm jack 223 is moved, and the pressing position of the rear end surface 208b of the electrode body 208 by the pressing shaft 223b. Is lower than the central axis C2. Further, as shown in FIG. 8A, when the central axis C2 of the electrode body 208 is inclined to the right with respect to the central axis C1 of the through-hole 210a, the worm jack 223 is moved and the pressing shaft 223b is used. The pressing position of the rear end surface 208b of the electrode body 208 is set to the left of the center axis C2. Conversely, when the center axis C2 of the electrode body 208 is tilted to the left with respect to the center axis C1 of the through hole 210a, the worm jack 223 is moved and the pressing position of the rear end surface 208b of the electrode body 208 by the pressing shaft 223b. Is to the right of the center axis C2.
That is, the pressing position of the rear end surface 208b of the electrode body 208 by the pressing structure 220 is such that the center axis C2 of the electrode body 208 is inclined with respect to the center axis C1 of the through hole 210a with respect to the center axis C2 of the electrode body 208. Decide on the opposite side of the direction.

As described above, after determining the pressing position and / or the pressing direction of the rear end surface 208b of the electrode body 208, a pressing step of pressing the rear end surface 208b of the electrode body 208 by the pressing member 220 is performed. Specifically, the rear end surface 208 b of the electrode body 208 is pressed by the pressing shaft 223 b of the worm jack 223 through the horizontal jig 221 and the vertical jig 222.

At this time, as shown in FIGS. 7A and 8A, in this embodiment, the pressing direction of the rear end surface 208b of the electrode body 208 is parallel to the central axis C1 of the through hole 210a. Therefore, even when the central axis C2 of the electrode body 208 is inclined with respect to the central axis C1 of the through hole 210a, the electrode body 208 is pushed by pushing the electrode body 208 along the central axis C1 of the through hole 210a. The inclination of the central axis C2 can be reduced. Therefore, the frictional resistance between the electrode body 208 and the through hole 210a when the electrode body 208 is pushed into the through hole 210a can be reduced.

In the present embodiment, the pressing position of the pressing member 220 is such that the center axis C2 of the electrode body 208 is inclined with respect to the center axis C1 of the through hole 210a with respect to the center axis C2 of the electrode body 208; It has been decided on the other side. Therefore, when the electrode body 208 is pressed by the pressing structure 220, a rotational force that reduces the inclination of the central axis C2 of the electrode body 208 with respect to the central axis C1 of the through hole 210a of the electrode body 208 acts on the electrode body 208. . Therefore, even when the central axis C2 of the electrode body 208 is inclined with respect to the central axis C1 of the through hole 210a, the electrode with respect to the central axis C1 of the through hole 210a is pushed out as the electrode body 208 is pushed in the direction of the molten glass MG. The inclination of the central axis C1 of the body 208 is reduced. Thus, as shown in FIGS. 7B and 8B, when the electrode body 208 is pushed out in the direction of the molten glass MG until the tip surface 208f of the electrode body 208 reaches the target position P0, the through hole The electrode body 208 can be pushed into the through-hole 210a so that the central axis C1 of 210a and the central axis C2 of the electrode body 208 coincide. Therefore, the frictional resistance between the electrode body 208 and the through-hole 210a is reduced, and the wall 210 of the liquid tank B of the dissolution tank 201 is prevented from being damaged by the pressing of the electrode body 208. Glass can be melted stably over a period of time.

Further, in this embodiment, when pressing the rear end surface of the electrode body 208 by the pressing structure 220, at least a part of the electrode body 208 protruding to the outside of the dissolution tank 201 intersects the central axis C1 of the through hole 210a. An electrode support base 230 is provided to support from the direction to perform. Therefore, when the electrode body 208 is pushed out in the direction of the molten glass MG, the center axis C2 of the electrode body 208 is prevented from being inclined downward with respect to the center axis C1 of the through hole 210a. In addition, since the height of the electrode support base 230 is adjustable, it is possible to more effectively prevent the electrode body 208 from being tilted by its own weight by appropriately setting the height of the electrode support base 230. .

As described above, according to the glass melting method, the glass substrate manufacturing method, and the glass melting apparatus of the present embodiment, the electrode body 208 and the through hole when the electrode body 208 is pushed into the through hole 208a of the melting tank 201. Friction resistance with 208a can be reduced, and the glass can be stably melted over a long period of time using the melting tank 201.

In addition, this invention is not limited to said embodiment, You may make various improvement and change in the range which does not deviate from the main point of this invention.
For example, the pressing of the electrode body 208 can be divided into a plurality of times, and the process of measuring the inclination of the rear end face 208b and the process of determining the pressing position or pressing direction of the pressing structure 220 can be repeated. Thereby, the pressing position and the pressing direction by the pressing structure 220 can be finely adjusted while measuring the inclination of the central axis C1 of the electrode body 208 with respect to the central axis C1 of the through hole 210a.
Further, depending on the degree of inclination of the rear end surface 208b of the electrode body 208, after appropriately determining the pressing position as described above, the electrode body 208 is directly pushed into the through hole 210a by the pressing structure 220 without changing the pressing direction. But it ’s okay.
Moreover, it is also possible to determine only the pressing direction as the optimum direction without changing the pressing position. In this case, the pressing direction is set so as to face the direction opposite to the direction in which the central axis C2 of the electrode body 208 is inclined with respect to the central axis C1 of the through hole 210a in the xz plane and the xy plane. Accordingly, a rotational force that reduces the inclination of the central axis C2 of the electrode body 208 with respect to the central axis C1 of the through hole 210a is applied to the electrode body 208, so that the central axis C2 of the electrode body 208 with respect to the central axis C1 of the through hole 210a The inclination can be reduced.
The pressing direction of the rear end surface 208b of the electrode body 208 may not be parallel to the central axis C1 of the through hole 210a as long as the inclination of the rear end surface 208b of the electrode body 208 can be reduced. For example, as shown in FIG. 7A, when the center axis C2 of the electrode body 208 is inclined downward with respect to the center axis C1 or the x axis of the through hole 210a, the electrode by the pressing shaft 223b of the worm jack 223 is used. The pressing direction may be determined so that the pressing direction of the rear end surface 208b of the body 208 faces obliquely upward. Conversely, when the center axis C2 of the electrode body 208 is inclined upward with respect to the center axis C1 or the x axis of the through hole 210a, the pressing direction of the rear end surface 208b of the electrode body 208 by the pressing shaft 223b of the worm jack 223 is The pressing direction may be determined so as to face obliquely downward. Further, as shown in FIG. 8A, when the center axis C2 of the electrode body 208 is inclined to the right with respect to the center axis C1 or the x axis of the through hole 210a, the electrode by the pressing shaft 223b of the worm jack 223 is used. The pressing direction may be determined so that the pressing direction of the rear end surface 208b of the body 208 faces diagonally to the left. Conversely, when the central axis C2 of the electrode body 208 is inclined to the left with respect to the central axis C1 or the x axis of the through hole 210a, the pressing direction of the rear end surface 208b of the electrode body 208 by the pressing shaft 223b of the worm jack 223 is The pressing direction may be determined so as to face diagonally right. Thus, by determining the pressing direction in the direction opposite to the direction in which the electrode body 208 is tilted, a rotational force that reduces the tilt is applied to the electrode body 208, and the tilt of the electrode body 208 can be reduced. .
In the above-described embodiment, the pressing structure 220 is configured to press the rear end surface 208b of the electrode body 208 via the horizontal jig 221 and the vertical jig 222. However, for example, a grid-like jig or a plate-like jig is used. You may press the rear-end surface 208b of the electrode body 208 using the jig | tool formed integrally.
In the above-described embodiment, the example in which the measurement gauge 225 is used as the measuring device has been described. However, if the distance between the reference surface R and the rear end surface 208b of the electrode body can be measured at a plurality of points, A non-contact type distance sensor such as an optical type may be used as the measuring device. In addition, an acceleration sensor may be provided on the rear end surface of the horizontal jig 221 and the gravitational acceleration may be measured using the acceleration sensor to obtain the inclination of the rear end surface of the electrode.
In the above-described embodiment, the electrode support base 230 is configured to support the electrode body 208 from below. However, the direction in which the electrode body 208 is indicated is not particularly limited as long as at least a part of the electrode body 208 protruding outside the dissolution tank 201 is supported from the direction intersecting the central axis C1 of the through hole 210a. . For example, the rear end portion of the electrode body 208 may be supported by being suspended from above, or may be supported from an oblique direction.

The method of the present invention makes it possible to advantageously perform a glass melting step particularly in the production of a glass substrate by molding molten glass.

201 Dissolution bath 208 Electrode body (electrode)
208b Rear end face 210a Through hole 220 Press structure (press member)
225 Measuring instrument C1, C2 Center axis MG Molten glass

Claims

In a method of melting glass stored in a melting tank provided with an electrode made of tin oxide in at least a pair of through holes,
A measurement step of measuring the inclination of the rear end face of the electrode with respect to the central axis of the through-hole when extruding the shortened electrode in the melting glass direction in the melting tank by a pressing member;
A determination step of determining a pressing direction of the pressing member based on the measurement result obtained in the measuring step;
Based on the pressing direction obtained in the determining step, a pressing step of pressing the rear end surface of the electrode by the pressing member;
A method for melting glass, comprising:
In the determination step,
Determining the pressing direction so as to reduce the inclination of the rear end face;
The method for melting glass according to claim 1.
In the pressing step,
In a state where at least a part of the electrode protruding outside the dissolution tank is supported from a direction intersecting the central axis of the through hole, the rear end surface of the electrode is pressed.
The method for melting glass according to claim 1 or 2.
A method for producing a glass substrate, comprising the glass melting method according to any one of claims 1 to 3.
A glass melting device,
A dissolution tank provided with an electrode made of tin oxide in at least a pair of through holes;
A pressing member for extruding the shortened electrode toward the molten glass in the melting tank;
A measuring instrument for measuring the inclination of the rear end face of the electrode with respect to the central axis of the through hole;
An apparatus for melting glass, comprising: