JP5944578B2 - Glass plate manufacturing method and glass plate manufacturing apparatus - Google Patents

Description

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

  Conventionally, the down draw method is used as one of the manufacturing methods of a glass plate. In the downdraw method, the molten glass overflowed from the molded body is diverted and flows down along the side surface of the molded body. Next, the molten glass is merged at the lower end of the formed body and formed into a glass plate. The formed glass plate is cooled while being conveyed downward in the vertical direction. In the cooling step, the glass plate transitions from the viscous region to the elastic region through the viscoelastic region.

  By the way, in a glass plate manufacturing apparatus using the downdraw method, generally, a slow cooling zone, which is a space in which a glass plate separated from a molded body is cooled without touching anything, is divided into a plurality of slow temperatures by a heat insulating plate. It is partitioned into a cold space. Insulation plates are used to control the atmospheric temperature of each slow cooling space to a desired temperature profile by suppressing the heat transfer between the slow cooling spaces and further suppressing the air flow that moves through each slow cooling space. Be placed. Here, the desired temperature profile means a temperature distribution in which no distortion occurs in the glass plate in each slow cooling space of the slow cooling zone. That is, the glass plate is adjusted to a desired temperature in each slow cooling space while being conveyed downward by the heat insulating plate. Therefore, the heat insulating plate is important for forming a glass plate with less distortion by slowly cooling the glass plate.

  However, the thickness of the glass plate that is gradually cooled in the slow cooling zone is generally larger at both ends in the width direction than at the center in the width direction. Therefore, as disclosed in Patent Document 1, when a glass plate is sandwiched between a pair of heat insulating plates formed of a single plate, at least both ends in the width direction where the thickness of the glass plate is the largest do not touch the heat insulating plate. It is necessary to set the size of the gap between the pair of heat insulating plates to the extent. However, the larger the gap, the more air flows that move through the slow cooling spaces, and heat exchange between the slow cooling spaces is facilitated through the gaps. There arises a problem that it is difficult to control the temperature profile to a desired level.

  As described above, a technique for performing thermal management by dividing a slow cooling zone into a plurality of slow cooling spaces by a heat insulating plate has been conventionally performed. On the other hand, in recent years, in glass substrates for liquid crystal display devices, required specifications (quality) such as deviations in thickness, warpage, and distortion of glass plates have become strict.

  As described above, when a glass plate is manufactured by the downdraw method, in order to reduce distortion, a desired temperature profile is designed in advance in each slow cooling space, so that the designed temperature profile is obtained. Perform thermal management of the atmosphere. However, striations may occur in the conveying direction of the glass plate if the atmospheric temperature in each slow cooling space cannot be controlled to a desired temperature profile in the state where an airflow moving through each slow cooling space is generated. This striae is a kind of distortion in which the thickness (height) of the glass plate fluctuates within a predetermined width, and is continuously generated in a streak shape in the conveying direction of the glass plate. In order to suppress the occurrence of striae and meet the recent strict required specifications, it is necessary to increase the accuracy of the designed temperature profile, and thus it is necessary to increase the accuracy of thermal management.

JP 2008-88005 A

  Therefore, the present invention provides a method for producing a glass plate and a glass plate capable of suppressing the striae of the glass plate by controlling the amount of heat possessed by the glass plate at a position where the striae are generated in the conveyance direction of the glass plate. An object is to provide a manufacturing apparatus.

The present invention has the following forms.
(Form 1)
A molding step of molding a glass plate from molten glass using the downdraw method;
A cooling step of cooling while conveying the glass plate formed in the forming step downward in the vertical direction;
A detection step of detecting the position of striae generated in the conveying direction of the glass sheet cooled in the cooling step and the amount of change due to the striae;
A determination step of determining a striae position where the amount of change detected in the detection step is equal to or greater than a reference amount,
At the position of the striae determined in the determination step, the amount of heat held by the glass plate is controlled so that the amount of change is equal to or less than the reference amount.
The manufacturing method of the glass plate characterized by the above-mentioned.

(Form 2)
A molding step of molding a glass plate from molten glass using the downdraw method;
A cooling step of cooling while conveying the glass plate formed in the forming step downward in the vertical direction;
A detection step of detecting the position of striae generated in the conveying direction of the glass sheet cooled in the cooling step and the amount of change due to the striae;
A determination step of determining a striae position where the amount of change detected in the detection step is equal to or greater than a reference amount,
In the cooling step, in the furnace chamber surrounded by the furnace wall, at the position of the striae determined in the determination step, the amount of heat held by the glass plate is controlled so that the amount of change is equal to or less than the reference amount.
The manufacturing method of the glass plate characterized by the above-mentioned.

(Form 3)
A molding step of molding a glass plate from molten glass using the downdraw method;
A cooling step of cooling while conveying the glass plate formed in the forming step downward in the vertical direction;
Detecting the position of the striae generated in the conveying direction of the glass plate cooled in the cooling step based on the thickness deviation or viscosity deviation of the glass plate, and
In the molding step or the cooling step, in the furnace chamber surrounded by the furnace wall, the furnace chamber is arranged at a position facing the glass plate, and the furnace chamber is divided into a plurality of spaces with respect to the conveyance direction of the glass plate. Using the heat insulating plate that changes the amount of heat held by the glass plate, the heat insulating plate gives the glass plate so that the striae satisfy a predetermined condition at the position of the stria detected in the detection step. Control the amount of heat,
The manufacturing method of the glass plate characterized by the above-mentioned.

(Form 4)
In the furnace chamber, a heat insulating plate that is disposed at a position facing the glass plate, divides the furnace chamber into a plurality of spaces with respect to the conveyance direction of the glass plate, and changes the amount of heat held by the glass plate. Prepared,
The heat insulating plate is provided with a plurality of heat quantity control devices in the width direction of the glass plate,
The calorific value control device facing the position of the striae detected in the detection step increases the amount of heat given to the glass plate.
The manufacturing method of the glass plate of the form 2 or 3 characterized by the above-mentioned.

(Form 5)
The heat insulating plate is divided into a plurality in the width direction of the glass plate,
In the cooling step, the distance between the glass plate to be cooled and the divided heat insulating plate facing the position of the striae detected in the detection step is narrowed.
The manufacturing method of the glass plate of the form 3 or the form 4 characterized by the above-mentioned.

(Form 6)
In the cooling step, a heat insulating plate is newly provided at the position of the striae detected in the detecting step, and the distance between the glass plate and the heat insulating plate is reduced.
The manufacturing method of the glass plate in any one of the forms 3-5 characterized by the above-mentioned.

(Form 7)
The striae have a predetermined width in the width direction of the glass plate and are continuously generated in the transport direction of the glass plate.
The manufacturing method of the glass plate in any one of the forms 1 to 5 characterized by the above-mentioned.

(Form 8)
A molding apparatus that forms a glass plate from molten glass using a downdraw method, and cools the molded glass plate while transporting it downward in the vertical direction;
Detection of the position of striae generated in the conveying direction of the glass sheet formed and cooled by the forming apparatus and the amount of change due to the striae, and detection of determining the position of striae where the amount of change exceeds a reference amount An apparatus,
In the furnace chamber surrounded by the furnace wall, the forming apparatus controls the amount of heat held by the glass plate so that the change amount is equal to or less than the reference amount at the position of the striae determined by the detection device.
An apparatus for producing a glass plate, characterized in that

(Form 9)
After the molten glass overflowed from the molded body flows down along both side surfaces of the molded body, a molding step of forming a glass plate by joining in the vicinity of the lower end of the molded body,
A cooling step of cooling while conveying the glass plate formed in the forming step downward in the vertical direction;
A detection step of detecting the position of striae generated in the conveying direction of the glass sheet cooled in the cooling step and the amount of change due to the striae;
A determination step of determining a striae position where the amount of change detected in the detection step is equal to or greater than a reference amount,
In the molding step,
It is arranged at a position facing the vicinity of the lower end portion of the molded body, and has a heat amount changing member that changes the amount of heat held by the glass plate,
At the position of the striae determined in the determination step, the amount of heat given to the glass plate by the heat amount change member is controlled so that the change amount detected in the detection step is equal to or less than the reference amount.
The manufacturing method of the glass plate characterized by the above-mentioned.

(Form 10)
In the molding step, the distance between the heat quantity change member and the glass plate is narrowed, and the retained heat amount of the glass plate at the position of the striae determined in the determination step is increased,
In the cooling step, the glass plate having an increased amount of retained heat is cooled while being pulled in the width direction of the glass plate.
The manufacturing method of the glass plate of the form 9 characterized by the above-mentioned.

(Form 11)
The width of the heat quantity change member is equal to the width of the striae detected in the detection step,
The manufacturing method of the glass plate of the form 9 or the form 10 characterized by the above-mentioned.

(Form 12)
The striae have a predetermined width in the width direction of the glass plate and are continuously generated in the transport direction of the glass plate.
The manufacturing method of the glass plate in any one of form 9 to form 11 characterized by the above-mentioned.

(Form 13)
After the molten glass that has overflowed from the molded body flows down along both side surfaces of the molded body, a molding apparatus that forms a glass plate by joining in the vicinity of the lower end of the molded body;
A cooling device that cools the glass plate formed by the forming device while conveying the glass plate downward in the vertical direction;
The position of the striae generated in the conveying direction of the glass plate cooled by the cooling device and the amount of change due to the striae are detected, and the position of the striae where the amount of change due to the detected striae is equal to or greater than a reference amount is detected. A determination device for determining,
The molding device includes:
It is arranged at a position facing the vicinity of the lower end portion of the molded body, and has a heat amount changing member that changes the amount of heat held by the glass plate,
At the position of the striae determined by the determination device, the amount of heat given to the glass plate by the heat amount changing member is controlled so that the amount of change is equal to or less than the reference amount.
An apparatus for producing a glass plate.

  According to the glass plate manufacturing method and the glass plate manufacturing apparatus of the above-described aspect, at the position where striae are generated in the conveying direction of the glass plate, the striae of the glass plate is controlled by controlling the amount of heat held by the glass plate. Can be suppressed

It is a schematic block diagram of the glass plate manufacturing apparatus concerning this embodiment. It is a cross-sectional schematic block diagram of a shaping | molding apparatus. It is a side surface schematic block diagram of a shaping | molding apparatus. It is a figure which shows one shape which planarly viewed the glass plate shape | molded with a shaping | molding apparatus. It is the schematic when the heat insulation member which pinches | interposes a glass plate is planarly viewed. It is the figure which showed the position of the striae of a glass plate. It is the figure which changed the position of the heat insulation board which pinches | interposes the glass plate seen planarly. It is the figure which showed the relationship between the distance from a glass plate to a heat insulating board, and the amount of distortion. It is the schematic at the time of planarly viewing the heat insulation member which pinches | interposes the glass plate concerning Embodiment 2. FIG. It is the schematic when the heat insulating member which pinches | interposes the glass plate concerning Embodiment 3 is planarly viewed. It is the schematic when the heat insulation member which pinches | interposes the glass plate concerning Embodiment 4 is planarly viewed. (A) is the cross-sectional schematic which expanded the lower end of the molded object concerning Embodiment 5, (b) is the figure seen planarly from the lower end side of the molded object in (a). It is the figure which showed the relationship between the distance from a glass plate to a heat insulating board, and the amount of distortion. It is the figure which planarly viewed the magnetic tube concerning Embodiment 6 from the lower end side of a molded object.

(Embodiment 1)
Hereinafter, the manufacturing method of the glass plate concerning this embodiment and the manufacturing apparatus of a glass plate are demonstrated. FIG. 1 is a schematic configuration diagram of a glass plate manufacturing apparatus according to the present embodiment.
As shown in FIG. 1, the glass plate manufacturing apparatus 100 includes a dissolution tank 200, a clarification tank 300, and a molding apparatus 400. In the melting tank 200, the glass raw material is melted to produce molten glass. The molten glass generated in the melting tank 200 is sent to the clarification tank 300. In the clarification tank 300, bubbles contained in the molten glass are removed. The molten glass from which bubbles have been removed in the clarification tank 300 is sent to the molding apparatus 400. In the forming apparatus 400, the glass plate G is continuously formed from the molten glass by, for example, an overflow down draw method. Thereafter, the molded glass plate G is cooled and cut into glass plates of a predetermined size. The glass plate G is, for example, a glass substrate for flat panel display (for example, a glass substrate for liquid crystal display, a glass substrate for plasma display, a glass substrate for organic EL display), a glass substrate for tempered glass such as a cover glass or a magnetic disk, It is used as a glass substrate on which electronic devices such as a glass substrate and a semiconductor wafer wound in a roll shape are laminated.

(Glass composition)
In the melting tank 200, the glass raw material is melted by a heating means (not shown) to produce molten glass. The glass raw material is prepared so that a glass having a desired composition can be substantially obtained. As an example of the composition of glass, non-alkali glass suitable as a glass substrate for panel display or flat panel display is SiO ₂ : 50 mass% to 70 mass%, Al ₂ O ₃ : 10 mass% to 25 mass%, B ₂ O ₃ : 0% by mass to 15% by mass, MgO: 0% by mass to 10% by mass, CaO: 0% by mass to 20% by mass, SrO: 0% by mass to 20% by mass, BaO: 0% by mass to 10% by mass %. Here, the total content of MgO, CaO, SrO and BaO is 5% by mass to 30% by mass. Alternatively, suitable glass substrate to the glass substrate and the LTPS glass substrate for a display for an oxide semiconductor _{display, SiO} 2: 55 wt% to 70 _wt%, Al ₂ O 3: 15 wt% to 25 _wt%, B 2 _{O 3} : 0% by mass to 10% by mass, MgO: 0% by mass to 10% by mass, CaO: 0% by mass to 20% by mass, SrO: 0% by mass to 20% by mass, BaO: 0% by mass to 10% by mass To do. Here, the total content of MgO, CaO, SrO and BaO is 5% by mass to 30% by mass. In this case, the glass substrate, the SiO ₂ 60 wt% to 70 wt%, and more preferably contains 3 wt% to 10 wt% of BaO.

As a glass substrate for a panel display or flat panel display, in addition to alkali-free glass, alkali trace glass containing a trace amount of alkali metal may be used. When the glass of the glass substrate is a non-alkali glass containing tin oxide or a glass containing a trace amount of alkali containing tin oxide, foreign matter of a platinum group metal aggregate produced by volatilization of the platinum group metal used on the inner wall of the fining tank 300 The effect which suppresses mixing with molten glass becomes remarkable. The alkali-free glass or the alkali trace-containing glass has a glass viscosity higher than that of the alkali glass. Since a lot of tin oxide is reduced in the melting step by increasing the melting temperature in the melting step, the molten glass temperature in the clarification step is increased in order to obtain a clarification effect, and the reduction of tin oxide is promoted, and It is necessary to reduce the viscosity of the molten glass. In addition, tin oxide has a higher temperature that promotes the reduction reaction than arsenous acid and antimony that have been used as a fining agent in the past, so that the temperature of the molten glass is increased to promote fining. It is necessary to increase the temperature of the inner wall of 300. In other words, when producing a non-alkali glass substrate containing tin oxide or a glass substrate of alkali trace-containing glass containing tin oxide, it is necessary to increase the molten glass temperature in the refining step. Is likely to occur. Note that the alkali-free glass substrate is glass that does not substantially contain alkali metal oxides (Li ₂ O, K ₂ O, and Na ₂ O). The alkali trace glass is a glass having an alkali metal oxide content (total amount of Li ₂ O, K ₂ O, and Na ₂ O) of more than 0 and 0.8 mol% or less. The alkali trace amount glass contains, for example, 0.1% by mass to 0.5% by mass of an alkali metal oxide as a component, and preferably 0.2% by mass to 0.5% by mass of an alkali metal oxide. . Here, the alkali metal oxide is at least one selected from Li ₂ O, Na ₂ O, and K ₂ O. The total content of alkali metal oxides may be less than 0.1% by mass.

In addition to the above components, the glass substrate produced according to the present embodiment has SnO ₂ 0.01 mass% to 1 mass% (preferably 0.01 mass% to 0.5 mass%), Fe ₂ O ₃ 0. You may further contain mass%-0.2 mass% (preferably 0.01 mass%-0.08 mass%). Glass substrate produced by the present embodiment, in consideration of the environmental _impact, do not contain _{As 2 O 3, Sb 2 O} 3 and PbO, or does not substantially contain.

Moreover, the glass substrate of the following glass compositions is further illustrated as a glass substrate manufactured by this embodiment. Therefore, the glass raw material is prepared so that the glass substrate has the following glass composition. For example, by _mol%, SiO 2 55 to 75 _{mol%, Al} 2 O 3 5 to 20 _{mol%, B} 2 O 3 0 to 15 mol%, RO 5 to 20 mol% (RO is MgO, CaO, SrO and BaO total amount), R ′ ₂ O 0-0.4 mol% (R ′ is the total amount of Li ₂ O, K ₂ O, and Na ₂ O), SnO ₂ 0.01-0.4 mol%, contains. At this time, it contains at least one of SiO ₂ , Al ₂ O ₃ , B ₂ O ₃ , and RO (R is all elements contained in the glass substrate among Mg, Ca, Sr and Ba), and the molar ratio ((2 × SiO ₂ ) + Al ₂ O ₃ ) / ((2 × B ₂ O ₃ ) + RO) may be 4.0 or more. A glass having a molar ratio ((2 × SiO ₂ ) + Al ₂ O ₃ ) / ((2 × B ₂ O ₃ ) + RO) of 4.0 or more is an example of a glass having a high temperature viscosity.

Next, a detailed configuration of the molding apparatus 400 will be described. FIG. 2 is a schematic cross-sectional view of the molding apparatus, and FIG. 3 is a schematic side view of the molding apparatus.
As shown in FIGS. 2 and 3, the forming apparatus 400 includes a formed body 10, a partition member 20, a cooling roller 30, heat insulating members 40a, 40b,..., 40h, and feed rollers 50a, 50b,. .., 50h and temperature control units (temperature control device, heat quantity control device) 60a, 60b,. Further, the molding apparatus 400 includes a molded body accommodating portion 410 that is a space above the partition member 20, a molding zone 42a that is a space immediately below the partition member 20, and a slow cooling zone 420 that is a space below the molding zone 42a. Have The slow cooling zone 420 has a plurality of slow cooling spaces 42b, 42c,. The molding zone 42a, the slow cooling space 42b, the slow cooling space 42c,..., 42h are stacked in this order from the upper side to the lower side in the vertical direction. The forming zone 42a and the slow cooling zone 420 are surrounded by a refractory material and / or a heat insulating material building (not shown). In the forming zone 42a and the slow cooling zone 420, the temperature control unit 60a or the like forms the glass plate G. Control to a temperature suitable for cooling.

  As shown in FIG. 2, the molded body 10 is a member having a substantially wedge-shaped cross-sectional shape. The molded body 10 is disposed in the molded body accommodating portion 410 such that the substantially wedge-shaped point is located at the lower end. As shown in FIG. 3, a groove 12 is formed on the upper end surface of the molded body 10. The grooves 12 are formed in the longitudinal direction of the molded body 10, that is, in the left-right direction on the paper surface of FIG. 3. A glass supply tube 14 is provided at one end of the groove 12. The groove 12 is formed so as to gradually become shallower as it approaches the other end from one end where the glass supply pipe 14 is provided. Guides that prevent the molten glass from protruding from the side wall are attached to both ends of the molded body 10 in the longitudinal direction. This guide has a wedge shape in plan view, and is made of a plate material having a size capable of covering the entire end surface of the molded body 10. With respect to the vertical direction, the position of the tip of the guide coincides with the lower end of the molded body 10. Due to the action of the guide, all of the molten glass can flow along the side wall. The glass plate G is formed by fusing the molten glass at the lower end, but since the molten glass is dammed by the guide, the molten glass accumulates in the vicinity of the guide, that is, at both ends in the longitudinal direction of the molded body 10. For this reason, the edge part G1 of the width direction of the glass plate G united by the lower end of the molded object 10 becomes a bulbous shape with thickness as shown in FIG. The width direction of the glass plate G refers to a direction orthogonal to the transport direction in the surface of the molten glass MG or in the plane of the surface of the glass plate G. Here, the end portion G1 refers to a portion having a predetermined thickness with respect to the plate thickness at the center in the width direction of the glass plate G. A region in the width direction sandwiched between the end portions G1 is referred to as a central region G2. Since the central region G2 is thinner than the end G1 and has a small amount of retained heat, the retained heat amount is likely to change due to turbulence of the airflow generated in the slow cooling zone 420, temperature unevenness of the temperature control unit 60, etc. Distortion is likely to occur. For this reason, it is necessary to strictly manage the cooling amount of the central region G2.

  The partition member 20 is a plate-like heat insulating material disposed in the vicinity of the lower end of the molded body 10. The partition member 20 is disposed such that the position of the lower end in the height direction is located below the position of the lower end of the molded body 10 in the height direction. The partition member 20 is arrange | positioned at the thickness direction both sides of the glass plate G, as shown in FIG. The partition member 20 divides the molded body housing portion 410 and the molding zone 42a, thereby suppressing heat transfer from the molded body housing portion 410 to the molding zone 42a. The partition member 20, which is a heat insulating material, partitions the molded body housing portion 410 and the molding zone 42 a because the spaces in the molded body housing portion 410 and the molding zone 42 a affect each other with respect to the temperature in the space. This is because temperature control is performed so as not to occur. In addition, the partition member 20 is arranged with the space between the glass plate G and the partition member 20 adjusted in advance so as to suppress the volume flow rate of the airflow entering the molded body accommodation unit 410 from the slow cooling zone 420. .

  The cooling roller 30 is disposed in the vicinity of the partition member 20 in the molding zone 42a. Moreover, the cooling roller 30 is arrange | positioned at the thickness direction both sides of the glass plate G, pinches | interposes the glass plate G in the thickness direction, and bears the role which cools the edge part G1 of the glass plate G, conveying a glass plate G below. .

  The heat insulating members 40a, 40b,..., 40h are formed in the slow cooling zone 420 in the slow cooling zone 420 with respect to the conveying direction (downward in the vertical direction) of the glass sheet G. -Dividing into 42h and suppressing the heat transfer in each of the gradually cooled spaces. In addition, the heat insulating members 40a, 40b,..., 40h are plate-like members disposed below the cooling roller 30 and on both sides in the thickness direction of the glass plate G, and slits that guide the glass plate G in the transport direction. Shaped space. As described above, the forming zone 42 a and the slow cooling zone 420 are surrounded by a refractory material and / or a heat insulating material building (not shown), but the glass plate G is carried out to the slow cooling zone 420. There is a slit-like space, and there are some gaps in the heat insulation building. For this reason, due to the chimney effect, an ascending airflow is generated in the slow cooling zone 420 from the lower side in the vertical direction toward the molding zone 42a. This airflow rises along the glass plate G, and the glass plate G is cooled by the airflow. Therefore, the heat insulating members 40a, 40b,. For example, as shown in FIG. 2, the heat insulating member 40a forms a molding zone 42a and a slow cooling space 42b, and the heat insulating member 40b forms a slow cooling space 42b and a slow cooling space 42c. The heat insulating members 40a, 40b,..., 40h suppress heat transfer between the upper and lower spaces. For example, the heat insulating member 40a suppresses heat transfer and rising airflow between the molding zone 42a and the slow cooling space 42b, and the heat insulating member 40b transfers heat and rise between the slow cooling space 42b and the slow cooling space 42c. Suppress airflow.

Each of the heat insulating members 40 a, 40 b,..., 40 h is arranged close to a position facing the glass plate G by combining a plurality of heat insulating plates 41. The heat insulating plate 41 is movable in the thickness direction of the glass plate G by an operating mechanism (not shown) so as to suppress heat transfer and ascending airflow. FIG. 5 is a schematic view when the heat insulating member 40 sandwiching the glass plate G is viewed in plan. In this embodiment, the heat insulation member 40 is arrange | positioned in the position which opposes the glass plate G, and the some heat insulation board 41 is connected and formed in the width direction of the glass plate G, as shown in the figure. There is a gap between the glass plate G and the heat insulating member 40 (heat insulating plate 41), and the distance D1 of this gap can be arbitrarily set by moving the heat insulating plate 41 in the direction of the glass plate G. If the glass G is cooled by the airflow passing through the gap of the distance D1, the glass plate G cannot be adjusted to a desired temperature, causing striae in the glass plate G. For this reason, the striae which generate | occur | produces in the glass plate G can be suppressed by moving the heat insulation board 41 which opposes the position where the striae occurred in the glass plate G, and adjusting the cooling amount of the glass plate G. .
In addition, the size and number of the heat insulating plates 41 can be arbitrarily set. For example, by reducing the size of the heat insulating plate 41 and connecting a large number of heat insulating plates 41, the heat insulating plate 41 at a position facing the position where the striae of the glass plate G are generated can be moved.

  A plurality of feed rollers 50a, 50b,..., 50h are arranged on both sides in the thickness direction of the glass sheet G in the slow cooling zone 420 at predetermined intervals in the vertical direction. The feeding rollers 50a, 50b,..., 50h are disposed in the slow cooling spaces 42b, 42c,..., 42h, respectively, and convey the glass plate G downward.

  The temperature control units 60a, 60b,..., 60h are composed of, for example, a sheathed heater, a cartridge heater, a ceramic heater, a temperature sensor, and the like that generate heat by resistance heating, dielectric heating, and microwave heating. 42h and the slow cooling spaces 42b, 42c,..., 42h are arranged along the width direction of the glass plate G, and the ambient temperature of the forming zone 42a and the slow cooling spaces 42b, 42c,. Control. Further, the temperature control units 60a, 60b,..., 60h form a predetermined temperature distribution (hereinafter referred to as “temperature profile”) designed so that the glass plate G is not warped or distorted. The ambient temperature of the molding zone 42a and the slow cooling spaces 42b, 42c,. Although the temperature (retained heat amount) of the glass plate G varies depending on the ambient temperature of the forming zone 42a and the slow cooling space 42b, etc., the temperature of the ambient temperature is difficult to be uniform, and when temperature unevenness with temperature difference occurs, Unevenness also occurs in the temperature of the plate G. The thickness of the central region G2 of the glass plate G is as thin as 0.05 to 1.0 mm, the amount of retained heat is likely to change, and warpage, distortion, and striae are likely to occur. The plate | board thickness of the center area | region G2 of the glass plate G concerning this embodiment becomes like this. Preferably it is 0.05-0.5 mm, More preferably, it is 0.05-0.3 mm. As the plate thickness of the glass plate G decreases, the amount of retained heat tends to change, and warpage, distortion, and plate thickness deviation tend to occur. Therefore, it is necessary to strictly control the cooling amount of the central region G2. Hereinafter, the temperature control units 60a, 60b,..., 60h are collectively referred to as the temperature control unit 60. Note that the upstream side refers to the side opposite to the conveying direction of the glass plate G, and in this embodiment refers to the side of the molded body 10 when viewed from the slow cooling zone 420.

  The detection device 70 is a portion that detects striae, and detects distortion or unevenness on the surface of the glass plate G at each position along the width direction of the glass plate G. The detection device 70 includes, for example, an optical sensor, an unevenness detector, and a strain detector, and the position and amount of strain generated in the glass plate G conveyed from the slow cooling zone 420 (slow cooling space 42h). (Strain value, skewness), thickness deviation, viscosity deviation, etc. are detected. The detection device 70 detects, for example, that there is a Y amount of distortion at a position of X1 mm to X2 mm from the left tip (left end portion G1) in the width direction of the glass plate G. In particular, the detection device 70 detects a striae having a thickness (height) variation in the glass plate G in a predetermined width (for example, a width of 10 mm). That is. The detection device 70 detects the distortion or the surface unevenness of the glass plate G, and measures the amount of change in the distortion or the amount of the surface unevenness. Since the thickness of the glass plate G is determined by the surface unevenness on both sides of the glass plate G, the surface unevenness includes a variation (plate thickness deviation) of the glass plate G. Further, since the amount of change in strain of the glass plate G is determined by the viscosity of the glass plate G, the amount of strain includes a variation in viscosity (viscosity deviation) of the glass plate G. Further, the detection device 70 determines whether or not the detected amount of change in distortion or the amount of surface irregularities is equal to or greater than a reference amount, and determines a position where this amount is equal to or greater than the reference amount as a position where striae has occurred. To do. The striae is that the molten glass MG leaves the lower end 11 of the molded body and simultaneously shrinks in the width direction of the glass plate G due to the surface tension, thereby generating surface irregularities of the glass plate G. This distortion is caused by the fact that it remains unsuppressed. Since striae are caused by the shrinkage of the glass plate G, the striae are continuously generated in a streak shape along the conveyance direction of the glass G. In addition, when a glass plate G is formed, a different glass component enters, and a part of the stored heat amount of the glass plate G containing the different glass component is different from the other part, so a portion with a different stored heat amount becomes striae. . In order to suppress this striae, it is necessary to control the temperature (retained heat amount) only at the position in the width direction where the irregularities occur in the glass plate G, but the temperature control unit that controls the ambient temperature of the slow cooling zone 420 In 60, it is difficult to control the temperature of only the streak-like portion, and the temperature profile may not be realized. For this reason, by adjusting the position of the heat insulating plate 41 based on the position of the striae detected by the detection device 70 and the amount of change due to striae (changes in surface irregularities, changes in strain), the temperature is increased in a streak shape. Only the temperature of a part of the glass plate G in which the change has occurred is controlled, and the striae of the glass plate G to be subsequently formed is suppressed.

The magnetic tube 80 is made of a magnetic metal material and is connected to a power supply device (not shown). When an alternating current flows from the power supply device to the induction coil, the magnetic field strength changes, and eddy currents are generated in the magnetic tube. Occur. When this eddy current flows through the magnetic tube 80, Joule heat is generated and the magnetic tube 80 generates heat. The magnetic tube 80 is excellent in heat resistance and erosion resistance, and is provided at a position on the upstream (upward) side of the partition member 20 at a position facing the lower end 11 of the molded body 10 that becomes high temperature, and an operating mechanism (not shown). ) Is movable in the thickness direction and the width direction of the glass plate G. By bringing the magnetic tube 80 close to or away from the molten glass MG (glass plate G), the amount of heat transferred from the magnetic tube 80 to the molten glass MG is adjusted, and distortion and unevenness generated in the glass plate G are suppressed. In addition, by arranging a plurality of magnetic tubes 80 in the width direction of the glass plate G, the amount of heat in the width direction of the glass plate G is adjusted to suppress distortion and unevenness generated in the glass plate G. Moreover, the magnetic tube 80 suppresses the amount of heat given to the glass plate G by blocking heat radiation from the temperature control unit 60, and controls the amount of heat held by the glass plate G.
The magnetic tube 80 is upstream of the strain point that can suppress the occurrence of strain (upper space side), for example, a position facing the lower end 11 of the molded body 10, a molding zone 42a, and a slow cooling zone 420 (slow cooling space 42b, 42c, ..., 42h). Here, the lower end 11 of the molded body 10 means, for example, within a range of 50 cm from the position of the lower end 11. In order to suppress striae and distortion generated in the glass plate G, temperature control of the glass plate G is performed from the lower end 11 of the molded body 10 to the vicinity of the strain point. In particular, in order to suppress striae, the temperature from the lower end 11 of the molded body 10 to the central region G2 becomes a slow cooling point, in particular, the temperature from the lower end 11 of the molded body 10 to the central region G2 is the glass softening point. It is preferable that the temperature control of the glass plate G is performed in the range up to the vicinity. In particular, in order to suppress the strain, it is preferable that the temperature control of the glass plate G is performed in the range from the annealing point to the strain point. Here, the vicinity of the glass softening point is preferably a temperature region from the glass softening point −20 ° C. to the glass softening point + 20 ° C. The diameter of the tube, the length of the tube, the shape of the tube, and the number of tubes in the magnetic tube 80 can be changed as appropriate based on the position of the strain generated in the glass plate G and the amount of strain. The magnetic tube 80 only needs to be able to change the temperature and viscosity of the molten glass MG by heating or cooling the molten glass MG (glass plate G). A heater, a heat generating member, a cooling member, or a heat quantity changing member may be used. Further, instead of the magnetic tube 80, a heat insulating plate or a heat shielding plate that suppresses the amount of heat given to the molten glass MG may be used.

Next, a method for suppressing striae (distortion) by reducing the cooling of the glass plate G and making the retained heat quantity uniform in the width direction will be described.
First, the glass plate G is shape | molded and annealed by the general overflow downdraw method. The method for forming and gradually cooling the glass plate G includes, for example, the contents described in JP-A-2008-88005, and the contents are taken into consideration. The glass plate G is molded through the molding zone 42a and the slow cooling zone 420 (slow cooling spaces 42b, 42c,..., 42h) controlled by a temperature profile designed so as not to cause distortion. A striae may occur in a part of the glass sheet G due to the turbulence of the air flow generated in the cold zone 420 or the like, or the temperature unevenness of the ambient temperature. For this reason, the position where the striae occurred and the amount of change due to the striae (changes in surface irregularities, distortions (distortion amount, strain value, distortion)) or the amount of irregularities are detected, The heat insulating plate 41 and the magnetic tube 80 are moved so that the striation is not generated in the glass plate G to be formed thereafter, and the retained heat amount of the glass plate G is made uniform to suppress the striae.

  Next, the detection device 70 detects the position in the width direction of the glass sheet G conveyed from the slow cooling zone 420 (slow cooling space 42h) and the amount of change (changes in surface irregularities and changes in strain). . FIG. 6 is a view showing the position in the width direction of the striae GS of the glass plate G. As shown in the figure, the detection device 70 detects the striae GS between positions X1 and X2 from the left end portion of the glass plate G being conveyed. Further, the detection device 70 detects the amount of change (change in surface irregularities, change in distortion) due to the detected striae GS. Specifically, the detection device 70 also functions as a determination device, and determines whether or not the detected amount of change is greater than or equal to a reference amount, and striae occur where the change amount is greater than or equal to the reference amount. Judge as position. Here, the reference amount varies depending on the required specifications of the glass plate G, and is arbitrary. When the change amount is equal to or greater than the reference amount, the detection device 70 determines that the striae GS at the detected positions X1 to X2 is a striae that should be suppressed so that the change amount is less than the reference amount. . The striae GS continuously generated in a streak pattern in the conveying direction of the glass plate G is generated due to the turbulence of the air current and the temperature unevenness of the ambient temperature. Unless it is, it continues to occur at a certain position (here, positions X1 to X2) in the width direction of the glass plate G. In addition, the amount of change due to the striae GS is basically constant because a portion of the glass plate G continues to be cooled in a streak shape in the conveyance direction unless the temperature unevenness is eliminated and the ambient temperature is made uniform. is there. For this reason, the striae GS can be suppressed by making the ambient temperature at the position where the striae GS occurs in the slow cooling zone 420 uniform and realizing a predetermined temperature profile. Although the temperature control unit 60 can control the ambient temperature, it is difficult to control the temperature only at the positions X1 to X2 where the striae GS is generated and to make the retained heat amount in the width direction of the glass plate G uniform. For this reason, by controlling the distance between the glass plate G and the heat insulating plate 41, the amount of heat retained by the glass plate G is made uniform.

  Next, the molding apparatus 400 controls the drive mechanism to set the position of the heat insulating plate 41 so that the ambient temperature near the positions X1 to X2 is uniform. FIG. 7 is a diagram in which the position of the heat insulating plate 41 sandwiching the glass plate G in plan view is changed. The forming apparatus 400 moves the heat insulating plate 41 at a position facing the positions X1 to X2 of the striae GS detected by the detecting device 70, and changes the distance between the glass plate G and the heat insulating plate 41 from D1 to D2. . FIG. 8 is a diagram showing the relationship between the distance from the glass plate G to the heat insulating plate 41 and the amount of change due to the striae GS (change in surface irregularities, change in strain). At the distance D1 from the glass plate G to the heat insulating plate 41, the amount of change due to the striae GS does not satisfy the required quality. Therefore, the molding apparatus 400 changes the position of the heat insulating plate 41, as shown in FIG. Change from D1 to distance D2. At the distance D2, the striae GS of the glass plate G satisfies the required quality. When the distance from the heat insulating plate 41 provided at the position opposite to the position where the striae GS is generated to the glass plate G is narrowed, the airflow passing through this position is suppressed and the cooling amount of the glass plate G is reduced. , The ambient temperature becomes uniform. That is, when the heat insulating plate 41 is brought close to the glass plate G, the heat radiation from the heat insulating plate 41 increases in a part of the glass plate G facing the heat insulating plate 41, and the glass plate G only at a position facing the heat insulating plate 41 is used. The temperature (retained heat amount) rises. Only the streaky position where the temperature of the glass plate G where the striae is generated is lowered can be heated, the clearance in the transport direction of the glass plate G is changed, and the temperature profile controlled by the temperature control unit 60 is realized. it can. And the change amount (change of surface unevenness | corrugation, change of distortion) of the glass plate G shape | molded after changing the distance from the glass plate G to the heat insulation board 41 to D2 will satisfy | fill required quality. Note that the relationship between the distance from the glass plate G to the heat insulating plate 41 and the amount of change (change in surface irregularities, change in strain) may be obtained by gradually changing the distance and detecting the amount of change, Further, the amount of change may be obtained by simulation from the ambient temperature and the temperature of the glass plate G.

The striae GS of the glass plate G occurs before the temperature of the glass plate G reaches the strain point. Here, the strain point refers to a strain point of general glass, and is a temperature (for example, 661 ° C.) corresponding to a viscosity of 10 ^14.5 poise. The strain point of the glass plate G may be 650 ° C or higher, more preferably 660 ° C or higher, further preferably 690 ° C or higher, and particularly preferably 730 ° C or higher. Glass having a high strain point tends to have a high viscosity of the glass being melted. The higher the viscosity of the glass, the more likely it is that striae GS is likely to occur when a different glass component enters when the glass plate G is formed, because the different glass component is less likely to diffuse. Therefore, a glass having a higher strain point is suitable for the present invention in which the effect of reducing the striae GS is remarkable. In order to suppress the striae GS, it is necessary to control the temperature (retained heat amount) of the glass plate G before the temperature of the glass plate G reaches −50 ° C. from the strain point. In the forming zone 42a and the slow cooling zone 420, the temperature of the glass plate G is −50 ° C. or higher from the strain point in the region from the heat insulating member 40a to the heat insulating member 40f. For this reason, by changing the position of the heat insulating plate 41 located from the heat insulating member 40a to the heat insulating member 40f and increasing the amount of heat applied from the heat insulating plate 41 to the glass plate G, the striae GS of the glass plate G is effectively obtained. Can be suppressed. The range in which the temperature control of the glass plate G is performed by the heat insulating plate 41 is the same as that of the magnetic tube 80.

  The forming device 400 repeats adjustment of the position of the heat insulating plate 41 based on the position of the striae GS detected by the detection device 70 and the amount of change due to the striae GS, thereby forming the glass to be formed after adjusting the position of the heat insulating plate 41. The striae GS of the plate G can be suppressed. In addition, when a plurality of striae GS exists in the glass plate G, the molding apparatus 400 repeatedly adjusts the position of the heat insulating plate 41 at a position facing the position where the plurality of striae GS is generated. The striae GS of the plate G can be suppressed.

As described above, according to the present invention, the position of the heat insulating plate facing the striae generated in the glass plate is adjusted, and the atmosphere temperature is made uniform, thereby adjusting the striae of the glass plate to be formed after the position adjustment. Can be suppressed. Further, by suppressing the air flow and reducing the cooling amount of the glass plate, a temperature profile designed so as not to cause striae can be realized.

(Embodiment 2)
Next, a method of suppressing the striae GS of the glass plate G by providing the heat insulating plate 41 along the heat insulating member 40 when the heat insulating member 40 is integrally formed will be described. In addition, description is abbreviate | omitted about the structure which is common in the above-mentioned embodiment.

  FIG. 9 is a schematic view when the heat insulating member sandwiching the glass plate according to the present embodiment is viewed in plan view. The heat insulating plate 41 is provided along the heat insulating member 40 as shown in FIG. The heat insulating plate 41 can be provided, for example, by being inserted into the slow cooling zone 420 from a slit through which the glass plate G formed at the lower end of the slow cooling space 42h is carried out. The method of providing the heat insulating plate 41 can be arbitrarily changed depending on the structure of the molding zone 42 a and the slow cooling zone 420.

  The molding apparatus 400 posts the position and strain amount of the striae GS detected by the detection apparatus 70, for example, to the operator of the molding apparatus 400. The position where the heat insulating plate 41 is provided is a position facing the position where the striae GS occurs, and the heat insulating plate 41 has a length that matches the length in the width direction of the striae GS, and the glass plate G It is the size which has the thickness from which the distance from the heat insulation board 41 becomes distance D2 which satisfy | fills required quality. As shown in FIG. 9, by providing the heat insulating plate 41 along the heat insulating member 40, the striae GS of the glass plate G formed after the heat insulating plate 41 is provided can be suppressed.

  As described above, according to the present invention, since the heat insulating plate corresponding to the position where the striae of the glass plate occurred and the amount of change due to the striae (change in surface unevenness, change in strain) can be provided, the glass The striae of the plate can be appropriately suppressed. Moreover, even if the heat insulating member is integrally formed, the distance from the glass plate to the heat insulating member (heat insulating plate) can be arbitrarily changed, so that the striae of the glass plate after the distance change can be suppressed. it can.

(Embodiment 3)
Next, a method for suppressing striae that occurs between the end G1 and the central region G2 of the glass plate G will be described. In addition, description is abbreviate | omitted about the structure which is common in the above-mentioned embodiment.

  As shown in FIG. 4, the glass plate G includes a central region G2 having a substantially uniform thickness and an end G1 having a thickness greater than that of the central region G2. Since both end portions G1 have a thickness compared to the central region G2 having a substantially uniform thickness, the amount of stored heat is larger than that of the central region G2, and there is a difference in the amount of stored heat between the both end portions G1 and the central region G2. A stress is generated between the both end portions G1 and the central region G2, warping the glass plate G, and distortion occurs. For this reason, the striae GS (distortion) is reduced by equalizing the amount of heat retained by the both ends G1 and the central region G2. The amount of change (amount of strain) varies depending on the distance from the glass plate G to the heat insulating member 40, as shown in FIG. For this reason, the distance from the edge part G1 to the heat insulation member 40 and the distance from the center area | region G2 to the heat insulation member 40 should be substantially equal, and these distance should just be below the distance which satisfy | fills required quality.

FIG. 10 is a schematic view when the heat insulating member sandwiching the glass plate according to the present embodiment is viewed in plan view. As shown in the figure, the heat insulating plate 41 has an inclined shape so that the distances from the end G1 and the central region G2 to the heat insulating plate 41 are substantially equal. Since the striae GS between the both end portions G1 and the central region G2 is generated due to the difference in the amount of retained heat due to the difference in the plate thickness, the amount of strain differs in the width direction. For this reason, by providing the heat insulating plate 41 having an inclined shape along the heat insulating member 40, the glass plate G is cooled by a temperature profile designed so that the ambient temperature is uniform and the striae GS does not occur. Thereby, striae GS of the glass plate G to be formed after the heat insulating plate 41 is provided can be suppressed.
The shape and size of the heat insulating plate 41 can be arbitrarily changed based on the width of the striae GS of the glass plate G and the amount of strain.

  As described above, according to the present invention, striae occurring at the end portion and the central region of the glass plate can be suppressed. In addition, even when the heat insulating member is formed integrally, the distance from the both ends and the central region to the heat insulating member (heat insulating plate) can be arbitrarily changed, so the striae of the glass plate after the distance change is suppressed. can do.

(Embodiment 4)
Next, a method of suppressing the striae of the glass plate G by providing a plurality of temperature control units (temperature control device, heat quantity control device) 60 on the heat insulating member 40 will be described. In addition, description is abbreviate | omitted about the structure which is common in the above-mentioned embodiment.

  FIG. 11 is a schematic view when the heat insulating member sandwiching the glass plate according to the present embodiment is viewed in plan view. As shown in the figure, the heat insulating member 40 is provided with a plurality of temperature control units 60 in the width direction of the glass plate G. In the temperature control unit 60, for example, the heat insulating member 40 is provided on the surface (side) and the reverse surface (side) facing the glass plate G, and the temperature (heat generation amount) is controlled to change the glass plate G from the heat insulating member 40. Controls the amount of heat applied to the. The temperature control unit 60 corresponding to the position of the striae GS detected by the detection device 70 increases the amount of heat generated, thereby increasing the amount of heat applied to the glass plate G and suppressing the striae GS generated in the glass plate G. can do.

  As described above, according to the present invention, the amount of heat can be increased in accordance with the position where the striae of the glass plate are generated and the amount of change due to striae (change in surface irregularities, change in strain). The striae of the glass plate can be appropriately suppressed. Moreover, even if it is a case where the heat insulation member is integrally formed, the calorie | heat amount given to a glass plate can be changed arbitrarily and the striae of a glass plate can be suppressed.

(Embodiment 5)
Next, a method for suppressing the striae of the glass sheet G by adjusting the installation positions of the plurality of magnetic tubes 80 will be described. In addition, description is abbreviate | omitted about the structure which is common in the above-mentioned embodiment.
The molding apparatus 400 controls the drive mechanism to set the position of the magnetic tube 80 provided near the lower end 11 of the molded body 10 so that the ambient temperature near the positions X1 to X2 is uniform. FIG. 12A is a schematic cross-sectional view in which the lower end 11 of the molded body 10 is enlarged, and FIG. 12B is a plan view from the lower end 11 side of the molded body 10 in FIG. As shown in FIG. 2, the magnetic tube 80 of the present embodiment is upstream of the partition member 20 that partitions the forming step and the cooling step (step of gradually cooling the glass plate G) in the conveying direction of the glass plate G (molding). (The side where the body 10 is located). The forming apparatus 400 moves the magnetic tube 80 to the same position in the width direction as the positions X1 to X2 of the striae GS detected by the detecting device 70, and sets the distance between the molten glass MG and the magnetic tube 80 to D1. By heating the molten glass MG and the glass plate G using the magnetic tube 80, the shrinkage that occurs when the glass plate G leaves the lower end 11 is suppressed. When the striae GS has occurred at the positions X1 to X2 detected by the detection device 70, when the glass plate G (molten glass MG) leaves the lower end 11, the striae GS has already occurred at the same positions X1 to X2. ing. For this reason, the shaping | molding apparatus 400 provides the viscosity of the glass plate G by providing the magnetic tube 80 in the position X1-X2 in the width direction, and heating the glass plate G (molten glass MG), as shown in the figure. Change to suppress shrinkage. FIG. 13 is a diagram showing the relationship between the distance from the molten glass MG to the magnetic tube 80 and the amount of change (change in surface irregularities, change in strain). In the case where the magnetic tube 80 is not provided at the position in the width direction where distortion and unevenness that cannot be removed in the slow cooling zone 420 (“no magnetic tube” in FIG. 13), the amount of change due to the stria GS detected by the detection device 70 (Changes in surface irregularities and distortions) do not satisfy the required quality. For this reason, the forming apparatus 400 controls the drive mechanism to move the magnetic tube 80 closer to the molten glass MG, and further, the distance between the molten glass MG and the magnetic tube 80 so as to satisfy the required specification D1. Set. That is, the distance is controlled so as to change according to the amount of change in distortion or the amount of surface irregularities obtained by measurement so that the glass plate G satisfies the required specifications. As shown in the figure, at the distance D1, the striae GS of the glass sheet G that has been slowly cooled in the slow cooling zone 420 satisfies the required quality. When the distance from the magnetic tube 80 provided at the position opposite to the position where the striae GS is generated to the molten glass MG is reduced, the amount of heat received by the molten glass MG from the magnetic tube 80 increases, and the viscosity of the molten glass MG decreases. Therefore, the viscosity of the glass plate G (molten glass MG) that is separated from the lower end 11 also decreases. The glass plate G separated from the lower end 11 is conveyed while the end portion G1 is sandwiched by the cooling roller 30 and is suppressed from contracting in the width direction, but the glass plate G having a low viscosity is easily deformed. When the glass plate G is pulled in the width direction by the cooling roller 30, the shrinkage is suppressed, and the striae GS generated in the glass plate G can also be suppressed. By setting the strain amount of the glass sheet G conveyed to the slow cooling zone 420 to a certain value or less, the change amount (strain amount) of the glass plate G that is temperature-controlled in the slow cooling zone 420 with a predetermined temperature profile is the required specification. Meet. For this reason, the amount of change (change in surface irregularities, change in strain) of the glass sheet G formed after the magnetic tube 80 is provided satisfies the required quality. The relationship between the distance from the molten glass MG to the magnetic tube 80 and the amount of change may be obtained by gradually changing the distance and detecting the amount of change, and the temperature, viscosity, etc. of the glass plate G Therefore, the amount of change may be obtained by simulation.

  The forming apparatus 400 adjusts the position of the magnetic tube 80 by repeatedly adjusting the position of the magnetic tube 80 based on the position of the striae GS detected by the detecting device 70 and the amount of change (distortion amount) due to the striae GS. The striae GS of the glass plate G to be formed later can be suppressed. In addition, when a plurality of striae GS is present on the glass plate G, the forming apparatus 400 moves the plurality of magnetic tubes 80 to positions in the width direction corresponding to the positions where the plurality of striae GS has occurred. Thus, the striae GS of the glass plate G can be suppressed.

  As described above, according to the present invention, before the glass plate is conveyed to the slow cooling zone, the strain amount and the unevenness are suppressed to a certain level or less, so that the amount of change due to the striae of the formed glass plate is required. It is possible to satisfy specifications, that is, requirements. Moreover, even if striae occur in the glass plate that does not satisfy the required specifications, it is possible to suppress the striae from occurring continuously. In addition, it is possible to suppress the occurrence of unevenness on the glass plate, which causes striae occurring on the glass plate.

(Embodiment 6)
Next, a method for suppressing the striae of the glass sheet G by adjusting the installation positions of the plurality of magnetic tubes 80 will be described. In addition, description is abbreviate | omitted about the structure which is common in the above-mentioned embodiment.

FIG. 14 is a plan view of the magnetic tube 80 according to the present embodiment as viewed from the lower end side 11 of the molded body 10. The magnetic tube 80 is provided near the lower end side 11 of the molded body 10 at a position facing the molten glass MG (glass plate G). The detection device 70 detects the position of the unevenness formed on the glass plate G and the amount of the unevenness, and when the detected unevenness amount is equal to or larger than the reference amount, striae occur at the detected unevenness position. judge. Positions X3 to X5 and positions X6 to X7 in the figure are positions determined by the detection device 70 as having striae. When there is striae at positions X3 to X5 of the glass G formed through the slow cooling zone 420 and the degree of striae is larger than the positions X4 to X5 at the positions X3 to X4, the forming apparatus 400 is In the vicinity of the lower end side 11, the magnetic tube 80 is moved to a position corresponding to the positions X3 to X5, and the distance between the magnetic tube 80 and the molten glass MG is set to the distance D2 at the positions X3 to X4 and at the positions X4 to X5. Install so that the distance is D3. The width of the magnetic tube 80 that functions as a heat amount changing member that changes the amount of heat given to the molten glass MG is adjusted to be equal to the width of the detected striae. Further, since the change amount and unevenness at the positions X3 to X4 are larger than the change amount and unevenness at the positions X4 to X5, at the positions X3 to X4, the position of the magnetic tube 80 is closer to the molten glass MG than the positions X4 to X5. , Distance D2 <distance D3. In addition, when the striae are formed at positions X6 to X7 on the surface different from the striae positions X3 to X5 of the glass G formed through the slow cooling zone 420, the forming apparatus 400 forms the striae. The magnetic tube 80 is moved to a position corresponding to the positions X6 to X7 in the vicinity of the lower end side 11 of the molded body 10 on the surface side, and further, the distance between the magnetic tube 80 and the molten glass MG is set to D4. Install. When the striae is wide (the distance to the positions X3 to X5 is long), a plurality of magnetic tubes 80 are arranged in the width direction of the molten glass MG so as to be the same distance as the distance to the positions X3 to X5. Is done. Thereby, the striae of the glass plate G formed after the plurality of magnetic tubes 80 are arranged can be reduced. In addition, when the amount of change differs in the striae generated in one place, the distance between the magnetic tube 80 and the molten glass MG is changed for each magnetic tube 80 to be the distances D2 and D3. Corresponding striae reduction can be performed. In the molding apparatus 400, a magnetic tube 80 is provided at a position in the width direction corresponding to the position of the stria detected by the detection device 70 in the vicinity of the lower end side 11 of the molded body 10, and the change amount detected by the detection device 70 is set. Based on this, by determining the distance between the magnetic tube 80 and the molten glass MG, it is possible to reduce distortion according to the position where the striae occurs and the amount of change.
Furthermore, it is preferable that the width of the magnetic tube 80 that functions as a heat amount changing member that changes the amount of heat given to the molten glass MG is adjusted to be equal to the width of the detected striae.

  As described above, according to the present invention, since the magnetic tube can be provided corresponding to the position and the amount of change in the striae of the glass plate, the striae of the glass plate can be appropriately suppressed. . In addition, since the installation position of the magnetic tube and the distance between the magnetic tube and the molten glass can be set arbitrarily, even if striae occur in a glass plate that does not meet the required specifications, the striae can be suppressed. it can.

  As mentioned above, although the manufacturing method and the manufacturing apparatus of the glass plate of this invention 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, various improvement and a change are carried out. Of course.

400 Molding device 410 Molded body accommodating portion 420 Slow cooling zone G Glass plate 20 Partition member 30 Cooling roller 40a, 40b, ... Heat insulating member 41 Heat insulating plate 42a Molding zone 42b, 42c, ... Slow cooling space 50a, 50b, ... Feed rollers 60a, 60b, ... Temperature control unit 70 Detector 80 Magnetic tube

Claims (13)

A molding step of molding a glass plate from molten glass using the downdraw method;
A cooling step of cooling while conveying the glass plate formed in the forming step downward in the vertical direction;
A detection step for detecting the position of the striae generated in the conveying direction of the glass sheet cooled in the cooling step and the amount of distortion due to the striae;
A determination step of determining a position of the striae in which the amount of distortion detected in the detection step is equal to or greater than a reference amount,
In the molding step or the cooling step, the glass plate is heated by a heat control device,
At the position of the striae determined in the determination step, the amount of heat held by the glass plate is controlled by blocking heat radiation from the heat amount control device so that the amount of distortion is equal to or less than the reference amount ,
In the cooling step, the glass plate is cooled while being pulled in the width direction of the glass plate .
The manufacturing method of the glass plate characterized by the above-mentioned. A molding step of molding a glass plate from molten glass using the downdraw method;
A cooling step of cooling while conveying the glass plate formed in the forming step downward in the vertical direction;
A detection step for detecting the position of the striae generated in the conveying direction of the glass sheet cooled in the cooling step and the amount of distortion due to the striae;
A determination step of determining a position of the striae in which the amount of distortion detected in the detection step is equal to or greater than a reference amount,
In the cooling step, in the furnace chamber surrounded by the furnace wall, the glass plate is heated by a heat quantity control device , and the strain amount is equal to or less than the reference amount at the position of the striae determined in the determination step. Control the amount of heat held by the glass plate by blocking heat radiation from the heat amount control device ,
Cooling while pulling the glass plate in the width direction of the glass plate ,
The manufacturing method of the glass plate characterized by the above-mentioned. A molding step of molding a glass plate from molten glass using the downdraw method;
A cooling step of cooling while conveying the glass plate formed in the forming step downward in the vertical direction;
Detecting the position of the striae generated in the conveying direction of the glass plate cooled in the cooling step based on the thickness deviation or viscosity deviation of the glass plate, and
In the molding step or the cooling step, in the furnace chamber surrounded by the furnace wall, the glass plate is heated by a calorie control device , and is disposed at a position facing the glass plate, with respect to the conveyance direction of the glass plate. The furnace chamber is divided into a plurality of spaces, and the striae satisfies a predetermined condition at the position of the striae detected in the detection step using a heat insulating plate that changes the amount of heat held by the glass plate. Controlling the amount of heat that the heat insulating plate gives to the glass plate by blocking heat radiation from the heat amount control device to satisfy the condition ,
In the cooling step, the glass plate is cooled while being pulled in the width direction of the glass plate .
The manufacturing method of the glass plate characterized by the above-mentioned. In the furnace chamber, a heat insulating plate that is disposed at a position facing the glass plate, divides the furnace chamber into a plurality of spaces with respect to the conveyance direction of the glass plate, and changes the amount of heat held by the glass plate. Prepared,
Wherein the heat insulating plate, a plurality of the heat control device is provided in the width direction of the glass plate,
The calorific value control device facing the position of the striae detected in the detection step increases the amount of heat given to the glass plate.
The manufacturing method of the glass plate of Claim 2 or 3 characterized by the above-mentioned. The heat insulating plate is divided into a plurality in the width direction of the glass plate,
Narrow the distance between the glass plate to be cooled and the divided heat insulating plate facing the position of the striae detected in the detection step,
The manufacturing method of the glass plate of Claim 3 or 4 characterized by the above-mentioned. A heat insulating plate is newly provided at the position of the striae detected in the detection step, and the distance between the glass plate and the heat insulating plate is reduced;
The manufacturing method of the glass plate of any one of Claims 3-5 characterized by the above-mentioned. The striae have a predetermined width in the width direction of the glass plate and are continuously generated in the transport direction of the glass plate.
The manufacturing method of the glass plate of any one of Claim 1 to 6 characterized by the above-mentioned. A molding apparatus that forms a glass plate from molten glass using a downdraw method, and cools the molded glass plate while transporting it downward in the vertical direction;
Detection of striae generated in the conveying direction of the glass plate formed and cooled by the forming device and the amount of distortion due to the striae, and detection for determining the position of striae where the amount of distortion exceeds a reference amount An apparatus,
The molding apparatus, wherein in a furnace chamber surrounded by a furnace wall, a heat controller for heating the glass plate, at the location of striae the detection device determines, as said distortion amount is equal to or less than the reference amount A heat quantity changing member that blocks heat radiation from a heat quantity control device and controls the amount of heat held by the glass plate, and a cooling roller that cools the glass plate while pulling in the width direction of the glass plate. Glass plate manufacturing equipment. After the molten glass overflowed from the molded body flows down along both side surfaces of the molded body, a molding step of forming a glass plate by joining in the vicinity of the lower end of the molded body,
A cooling step of cooling while conveying the glass plate formed in the forming step downward in the vertical direction;
A detection step for detecting the position of the striae generated in the conveying direction of the glass sheet cooled in the cooling step and the amount of distortion due to the striae;
A determination step of determining a position of the striae in which the amount of distortion detected in the detection step is equal to or greater than a reference amount,
In the forming step, the glass plate is heated by a heat quantity control device, and the glass is formed by blocking heat radiation from the heat quantity control device by a heat quantity change member disposed at a position facing the vicinity of the lower end portion of the molded body. Change the amount of heat held by the board ,
At the position of the striae determined in the determination step, the amount of heat given to the glass plate by the heat amount change member is controlled so that the amount of strain determined in the detection step is equal to or less than the reference amount ,
In the cooling step, the glass plate is cooled while being pulled in the width direction of the glass plate .
The manufacturing method of the glass plate characterized by the above-mentioned. In the molding step, the distance between the heat quantity change member and the glass plate is narrowed, and the retained heat amount of the glass plate at the position of the striae determined in the determination step is increased,
In the cooling step, the glass plate having an increased amount of retained heat is cooled while being pulled in the width direction of the glass plate.
The manufacturing method of the glass plate of Claim 9 characterized by the above-mentioned. The width of the heat quantity change member is equal to the width of the striae detected in the detection step,
The manufacturing method of the glass plate of Claim 9 or 10 characterized by the above-mentioned. The striae have a predetermined width in the width direction of the glass plate and are continuously generated in the transport direction of the glass plate.
The manufacturing method of the glass plate of any one of Claim 9 to 11 characterized by the above-mentioned. After the molten glass that has overflowed from the molded body flows down along both side surfaces of the molded body, a molding apparatus that forms a glass plate by joining in the vicinity of the lower end of the molded body;
A cooling device that cools the glass plate formed by the forming device while conveying the glass plate downward in the vertical direction;
The cooling device detects a distortion amount due to the position and the striae striae occurring in the conveying direction of the glass plate was cooled, the amount of distortion caused by the detected striae, the position of the striae to be a reference amount or more A determination device for determining,
The molding device includes:
A heat control device for heating the glass plate;
A heat amount changing member that is disposed at a position facing the vicinity of the lower end of the molded body and changes the amount of heat held by the glass plate by blocking heat radiation from the heat amount control device ;
A cooling roller that cools the glass plate while pulling in the width direction of the glass plate;
Have
At the position of the striae determined by the determination device, the amount of heat given to the glass plate by the heat amount changing member is controlled so that the amount of distortion is equal to or less than the reference amount.
An apparatus for producing a glass plate.

Images