TW201412650A - Method of manufacturing glass substrate and cooler - Google Patents

Abstract

This invention provides a method of manufacturing a glass substrate which can effectively and controllably excellently perform heat exchange in a space where a formed glass plate is cooled. In the method of manufacturing a glass substrate according to the present invention, in at least a part of the space for cooling a glass plate 90 leaving from a formed body 10 to close to a slow cooling point, cooling rate control members 41a to 41f are disposed. A rear cooling space 422 at the opposite side of the glass plate 90 spaced by the cooling rate control members comprises cooling rooms 422a to 422f arranged along the advancing direction of the glass plate 90. The cooling rooms 422a to 422f are cooled by coolers 51a to 51f. The cooler 51b comprises a thermal insulation plate 52b and a coolant pipe 53b. The thermal insulation plate 52b inhibits the heat transfer between the cooling room 422b and the space along the advancing direction and adjacent to the cooling room 422b. The coolant pipe 53b uses the liquid coolant flowing therein to cool the cooling room.

Description

Glass substrate manufacturing method and cooler

The present invention relates to a method of manufacturing a glass substrate and a cooler.

Previously, as a method of manufacturing a glass substrate, an overflow down-draw method was used. In the overflow down-draw method, the molten glass which has overflowed from the molded body flows down the both sides of the molded body, and then merges in the vicinity of the lower end portion of the molded body to form the glass sheet. The formed glass sheet is cooled while being stretched toward the lower side. The cooled glass plate is cut into a specific size to obtain a glass substrate.

In the overflow down-draw method, when cooling the formed glass sheet, a technique of controlling the cooling rate of the glass sheet is used. For example, Patent Document 1 (International Publication No. 2012/018072) discloses a method of arranging a plurality of cooling rate control members along a traveling direction of a glass sheet in a space below the molded body, and cooling each of them. The speed control member blows a gas of a specific temperature, thereby controlling the temperature of the glass sheet. In order to achieve a final thickness of the glass sheet after the forming, the glass sheet which has just been removed from the lower end of the formed body is rapidly cooled in the patent document 2 (Japanese Patent Publication No. 2009-502706). method.

Background art literature Patent literature

Patent Document 1: International Publication No. 2012/018072

Patent Document 2: Japanese Patent Application Publication No. 2009-502706

However, in the method of rapidly cooling the glass sheet which has just been separated from the lower end of the molded body, the method of cooling the glass sheet is not sufficient in the method of using the cooling rate controlling member disclosed in Patent Document 1. Further, in this method, the temperature difference in the width direction of the glass sheet due to the gas blown to the cooling rate control member causes a temperature difference of the glass sheet. Further, in this method, a part of the gas blown to the cooling rate control member unexpectedly leaks and collides with the glass sheet, resulting in a temperature difference of the glass sheet. Moreover, due to the temperature difference of the glass sheets, there is a possibility that the variation in the thickness of the glass sheets is increased.

An object of the present invention is to provide a method for producing a glass substrate which can efficiently and controlly exchange heat with a glass sheet in a space for cooling a formed glass sheet, and can efficiently perform heat source with a heat source. Heat exchanger cooler.

The method for producing a glass substrate of the present invention includes a forming step, a cooling step, and a cutting step. In the molding step, the molten glass is allowed to overflow from the molded body to form a glass plate. In the cooling step, the formed glass sheet is cooled while being stretched toward the lower side. In the cutting step, the cooled glass plate is cut to obtain a glass substrate. A cooling rate control member is provided to cool at least a portion of the glass plate from which the molded body is separated to a space near the slow cooling point. The cooling rate control member faces the surface of the central portion in the width direction of the glass sheet. The cooling space is formed by a cooling chamber disposed along the traveling direction of the glass sheet after being positioned on the opposite side of the glass sheet via the cooling rate control member. At least a portion of the cooling chamber is cooled by a cooler. In the cooling step, the glass sheet is moved in one direction along the traveling direction by one side of the cooling rate control member contacting the cooling chamber, and the gradation or continuity is cooled. At least a portion of the cooler includes a heat shield and a coolant tube. The heat shield suppresses thermal movement between the cooling chamber and the space adjacent to the cooling chamber along the direction of travel. The coolant tube cools the cooling chamber by flowing the liquid coolant inside.

In the method for producing a glass substrate, the glass plate that has just left the lower end of the molded body is used Cool down to the cooler and near the slow cooling point. The cooler is composed of a heat shield and a coolant tube. The heat shield is used to divide the rear cooling space into partition walls of a plurality of cooling chambers along the traveling direction of the glass sheet, that is, in the vertical direction. The coolant tube exchanges heat between the liquid coolant flowing inside and one of the two spaces separated by the heat shield plate by radiant heat transfer and natural convection heat transfer. The cooler can control the amount of heat exchange by adjusting the flow rate of the liquid coolant inside the coolant tube or changing the temperature of the liquid coolant. Further, when it is desired to further increase the cooling rate adjustable range, it is necessary to increase or decrease the number of round trips of the coolant tubes to change the surface area of the coolant tubes or to change the temperature of the liquid coolant supplied to the coolant tubes.

Therefore, the method for producing a glass substrate can efficiently exchange heat with the glass sheet in a space for cooling the formed glass sheet.

Further, the cooling step preferably includes a first cooling step and a second cooling step. In the first cooling step, the glass plate is cooled at the first average cooling rate until the temperature in the central portion of the glass plate reaches the slow cooling point. In the second cooling step, the glass plate is cooled at the second average cooling rate until the temperature in the central portion of the glass plate reaches a temperature 50 ° C lower than the strain point from the slow cooling point. The first average cooling rate is preferably greater than the second average cooling rate.

In the first cooling step, the temperature in the central portion of the glass plate is from 1200 ° C to the slow cooling point, and the influence of the heat shrinkage rate is small. In this temperature region, since the glass molecules are easily moved, it is difficult to generate strain. On the other hand, in the second cooling step, since the temperature in the central portion of the glass sheet is in the vicinity of the slow cooling point to the strain point, the influence of the heat shrinkage rate is large, so it is preferable to cool as slowly as possible. In this temperature region, the time required for the movement of the glass molecules is longer than that of the first cooling step, and strain is likely to occur. Therefore, the first average cooling rate is preferably larger than the second average cooling rate.

Further, in the cooling step, it is preferable to control the cooling rate of the glass sheet in the traveling direction by the cooling rate controlling member. The cooling rate control member can make the temperature in the width direction of the glass sheet uniform.

Moreover, it is preferable to set a space for cooling the glass plate from which the molded body leaves. An end portion cooling device that cools the end portion of the glass sheet in the width direction. In the cooling step, the glass plate is cooled by means of an end cooling device so that the end of the glass plate is cooled at a speed greater than the central portion of the glass plate. The end cooling device suppresses the shrinkage of the glass sheet in the width direction.

Further, it is preferable to provide a heat insulating member along the width direction of the glass sheet on the surface of the cooling rate control member opposite to the opposing surface of the glass sheet. In the cooling step, the thickness and/or warpage of the width direction of the glass sheet is controlled by the heat insulating member.

Further, in the cooling step, it is preferred that the temperature in the central portion of the glass sheet reaches at least a portion of the space near the softening point, and the thickness of the glass sheet is controlled according to the thickness distribution of the glass sheet by the change in the size of the heat insulating member. .

In the cooling step, the temperature distribution in the width direction of the glass sheet can be controlled by using the heat insulating member. Thereby, in the cooling step, a temperature distribution of the glass sheet suitable for reducing the thickness deviation and warpage of the glass sheet can be achieved.

Further, in the cooling step, preferably, after controlling the thickness of the glass sheet, the temperature of the glass sheet is gradually or continuously lowered from the central portion of the glass sheet toward the end portion by changing the size of the heat insulating member. Distribution, controlling the warpage of the glass sheet in such a way that the flatness is within a certain range.

The cooler of the present invention is used to cool a space, and the cooler includes a heat shield and a coolant tube. The heat shield divides the space into a plurality of cooling chambers and inhibits thermal movement between adjacent cooling chambers. The coolant tube cools the cooling chamber by means of an internal flowing liquid coolant.

In the cooler, the coolant pipe exchanges heat between the liquid coolant flowing inside and the two spaces separated by the heat insulating plate by radiant heat transfer and natural convection heat transfer. The cooler can control the amount of heat exchange by adjusting the flow rate of the liquid coolant inside the coolant tube, or changing the temperature of the liquid coolant, and changing the surface area of the coolant tube by changing the surface area of the coolant tube.

Therefore, the cooler can be effective in the space where the heat source exists and excellent in controllability. The heat source performs heat exchange.

Further, it is preferable that the coolant tubes are arranged to be reciprocated a plurality of times at intervals of an outer diameter or more, and form a plane which is a plane including a row of the reciprocating coolant tubes. The heat shield forms one side of the wall surface of the cooling chamber and is disposed parallel to the tube plane and in contact with the tube plane, and is disposed on the row of the coolant tubes by its own weight.

The cooler enables a larger surface area of the cooling tube that is in contact with the surrounding atmosphere, and thus allows for more efficient heat exchange with the heat source in the space where the heat source is present. Further, since the size of the cooling pipe in the vertical direction is small, the cooler can be disposed without lowering the heat exchange efficiency even when the installation space size in the vertical direction is limited.

Further, the cooler preferably has a rigidity such that the amount of deformation due to the self-weight of the central portion in the longitudinal direction is 20 mm or less in the longitudinal direction in a state where both end portions are supported. Therefore, the central portion of the cooler in the longitudinal direction need not be supported.

The method for producing a glass substrate of the present invention can efficiently exchange heat with a glass plate in a space in which the glass plate after molding is cooled. The cooler of the present invention is effective for heat exchange with a heat source in a space in which a heat source is present.

10‧‧‧Formed body

12‧‧‧ slot

14‧‧‧Glass supply tube

20‧‧‧ Upper spacers

30‧‧‧Cooling roller

40‧‧‧Cooling unit

41a~41f‧‧‧Cooling speed control unit

42‧‧‧End cooling unit

42a‧‧‧Water-cooled board

42b‧‧‧Water supply pipe

42c‧‧‧Drainage pipe

43‧‧‧Insulation components

51a~51f‧‧‧cooler

52b‧‧‧insulation board

53b‧‧‧ coolant tube

54b‧‧‧Support

60‧‧‧lower spacer members

62a‧‧‧Bend

62b‧‧‧Bend

62c‧‧‧Bend

63a‧‧‧ Main Department

70‧‧‧ Pull down roller

80‧‧‧Solid glass

90‧‧‧ glass plate

90a‧‧‧Central area

90b‧‧‧ Both ends

91‧‧‧Corner tube

92‧‧‧Long elbow

93‧‧‧Inflow pipe

94‧‧‧Outflow tube

95‧‧‧ tube plane

100‧‧‧Glass substrate manufacturing equipment

151b‧‧‧cooler

152b‧‧‧heat insulation board

153b‧‧‧ coolant tube

154b‧‧‧Support

191‧‧‧ round tube

192‧‧ long elbow

193‧‧‧Inflow pipe

194‧‧‧Outflow tube

200‧‧‧melting tank

300‧‧‧Clarification tank

400‧‧‧Forming device

410‧‧‧Formed body containment space

420‧‧‧Cooling space

422‧‧‧ Rear cooling space

422a~422f‧‧‧cooling room

430‧‧‧Slow space

h‧‧‧Size

T‧‧‧thickness

W‧‧‧ size

Fig. 1 is a schematic configuration diagram of a liquid glass substrate manufacturing apparatus for carrying out the liquid.

Figure 2 is a front view of the forming apparatus.

Figure 3 is a cross-sectional view of the forming apparatus of the line III-III of Figure 2.

Fig. 4 is an external view of a cooling rate control member.

Figure 5 is an enlarged view of Figure 2 in the vicinity of the cooling rate control member.

Figure 6 is an external view of the end cooling device.

Figure 7 is an external view of the cooler.

Figure 8 is a side view of the cooler.

Figure 9 is a plan view of the cooler of Modification A.

Figure 10 is a side view of the cooler of Variation A.

(1) The entire composition of the glass substrate manufacturing apparatus

The embodiment of the method for producing a glass substrate and the cooler of the present invention will be described with reference to the drawings. Fig. 1 is a schematic configuration diagram of a glass substrate manufacturing apparatus 100 used in the present embodiment. As shown in FIG. 1, the glass substrate manufacturing apparatus 100 includes a melting tank 200, a clarification tank 300, and a forming apparatus 400. In the melting tank 200, the glass raw material is heated to form a molten glass. In the clarification tank 300, the bubbles contained in the molten glass formed in the melting tank 200 are removed. In the molding apparatus 400, the glass frit is continuously formed by the overflow down-draw method from the molten glass in which the bubble has been removed in the clarification tank 300. The formed glass sheet is cut into a specific size to obtain a glass substrate of the product size. The glass substrate is bundled and shipped out through the end surface processing step, the cleaning step, and the inspection step.

A glass substrate manufactured by the glass substrate manufacturing apparatus 100 can be used for manufacturing a flat panel display (FPD) such as a liquid crystal display, a plasma display, and an organic EL display. The glass substrate has a thickness of, for example, 0.2 mm to 0.8 mm, and has a size of 680 mm to 2200 mm in length and 880 mm to 2500 mm in width.

(2) Detailed composition of the forming device

2 is a front view of the forming device 400. 2 is an external view of the forming apparatus 400 as viewed in a direction perpendicular to the surface of the glass sheet 90 formed by the forming apparatus 400. Figure 3 is a cross-sectional view of the forming apparatus 400 taken along line III-III of Figure 2. The molding apparatus 400 mainly includes a molded body 10, an upper partition member 20, a cooling drum 30, a cooling unit 40, coolers 51a to 51f, a lower partition member 60, a pull-down drum 70, and a control device (not shown).

(2-1) Shaped body

As shown in FIG. 3, the molded body 10 has a substantially wedge-shaped cross-sectional shape of a pentagonal shape. The molded body 10 is formed of a refractory brick and is disposed in a molded body accommodating space 410 which is a space above the upper partition member 20. The molded body 10 is located at the tip end of a substantially wedge-shaped cross-sectional shape The way the lower end is set.

A groove 12 is formed on the upper end surface of the molded body 10 along the longitudinal direction of the molded body 10. A glass supply tube 14 that communicates with the groove 12 is attached to an end portion of the molded body 10 in the longitudinal direction. The groove 12 is formed to gradually become shallow as it goes from one end to the other end of the glass supply tube 14.

The molten glass sent from the clarification tank 300 flows into the tank 12 via the glass supply pipe 14. The molten glass 80 overflowing from the groove 12 of the molded body 10 flows down the both sides of the formed body 10, and merges near the lower end of the formed body 10. The molten glass 80 after the merging becomes the glass plate 90. The glass plate 90 is continuously formed and cooled while flowing down the upper space member 20 and the space above the lower partition member 60, that is, the space inside the cooling space 420.

(2-2) Upper spacer member

The upper partition member 20 is a pair of plate-shaped heat insulating members provided near the lower end of the molded body 10. As shown in FIG. 3, the upper partition members 20 are provided on both sides in the thickness direction of the glass sheet 90. The upper partition member 20 is partitioned into a molded body accommodating space 410 and a cooling space 420 in the vertical direction. The molded body accommodating space 410 is a space in which the molded body 10 is provided. The cooling space 420 is a space in which the glass plate 90 is cooled while being cooled. The upper partition member 20 blocks thermal movement from the molded body accommodating space 410 to the cooling space 420.

(2-3) Cooling roller

The cooling drum 30 is a member for quenching the glass sheet 90 flowing down in the cooling space 420. As shown in FIG. 2, the cooling drum 30 cools both ends of the glass plate 90 in the width direction. As shown in FIG. 3, the cooling drums 30 are disposed on both sides in the thickness direction of the glass sheet 90. Therefore, the glass plate 90 is rapidly cooled by the two pairs of cooling drums 30 passing through both end portions in the width direction.

(2-4) Cooling unit

The cooling unit 40 cools the glass sheet 90 to a unit near the slow cooling point while adjusting the cooling rate of the glass sheet 90 flowing down in the cooling space 420. Here, near the slow cooling point It is a temperature region from the temperature at which the slow cooling point of the glass plate 90 is added to 100 ° C to the strain point of the glass plate 90 plus the slow cooling point of the glass plate 90 and then divided by the temperature obtained by 2. The cooling unit 40 is controlled such that the glass sheet 90 is cooled stepwise or continuously along the flow direction of the glass sheet 90. The cooling unit 40 mainly includes cooling rate control members 41a to 41f, an end portion cooling device 42, and a heat insulating member 43.

(2-4-1) Cooling speed control member

In the present embodiment, as shown in FIG. 3, six pairs of cooling rate control members 41a to 41f are provided in the cooling space 420 below the upper partition member 20. The cooling rate control members 41a to 41f are provided along the downward direction of the glass sheet 90, that is, in the vertical direction. The cooling rate control members 41a to 41f are arranged without gaps in the vertical direction. Further, the number of the cooling rate control members 41a to 41f disposed in the vertical direction may be different depending on the size of the forming device 400 and the cooling step to be set in the cooling step near the slow cooling point of the glass sheet 90. The number is determined as appropriate.

The cooling rate control member 41a is provided in the most upstream direction of the six cooling rate control members 41a to 41f with respect to the downward flow direction of the glass sheet 90. The cooling rate control member 41f is disposed at the most downstream side of the six cooling rate control members 41a to 41f with respect to the downward flow direction of the glass sheet 90. The cooling rate control member 41a is provided adjacent to the lower side of the upper partition member 20, and the cooling rate control member 41f is disposed substantially above the lower partition member 60. Each of the cooling rate control members 41a to 41f has the same configuration. Next, the configuration of the cooling rate control members 41a to 41f will be described using the cooling rate control member 41a as an example.

A pair of cooling rate control members 41a are respectively disposed near both surfaces of the glass sheet 90. The cooling rate control member 41a is a member that extends in the width direction of the glass sheet 90, that is, in the horizontal direction. As shown in FIG. 2, the cooling rate control member 41a is disposed at a position opposed to the surface of the central portion 90a in the width direction of the glass sheet 90. Hereinafter, the central portion 90a of the glass sheet 90 includes a portion of the object having a uniform thickness, and the end portion 90b of the glass sheet 90 includes a portion of the object to be cut after the manufacture. The length of the cooling rate control member 41a The length of the direction is shorter than the length of the glass plate 90 in the width direction.

Fig. 4 is an external view of a portion of the cooling rate control member 41a. The cooling rate control member 41a is a plate-shaped metal member that has been bent and processed. Preferably, the metal member has a heat resistance of 600 ° C or higher in the atmosphere, and has at least 30 W / m. The thermal conductivity above K has an emissivity characteristic of 0.85 or more in the use temperature region. The metal member of the cooling rate control member 41a is, for example, pure nickel.

As shown in FIG. 4, the cooling rate control member 41a includes a guide groove (groove steel) of the bent portion 62a and the main portion 63a. The bent portion 62a is a horizontal portion formed by bending the metal member at both end portions of the cooling rate control member 41a in the vertical direction. The main portion 63a is a vertical portion other than the bent portion 62a. The main portion 63a has a surface facing the glass plate 90. The dimension h of the main portion 63a in the vertical direction is, for example, 50 mm to 250 mm. The main portion 63a preferably has a thickness t of, for example, 4 mm or more. The dimension w of the bent portion 62a in the horizontal direction is, for example, 40 mm to 90 mm.

Fig. 5 is an enlarged view of Fig. 2 in the vicinity of the cooling rate control member 41a. The end cooling device 42 is omitted in FIG. As shown in FIG. 3, the cooling rate control member 41a is connected to the cooling rate control member 41b adjacent to the vertical direction by screwing. Specifically, the bent portion 62a on the lower side of the cooling rate control member 41a is coupled to the bent portion 62b on the upper side of the cooling rate control member 41b by screwing. Similarly, the bent portion 62b on the lower side of the cooling rate control member 41b is coupled to the bent portion 62c on the upper side of the cooling rate control member 41c by screwing.

In FIG. 3, the rear cooling space 422 is located in a space on the opposite side of the glass plate 90 with the cooling rate control members 41a to 41f interposed therebetween. That is, the rear cooling space 422 is located in the space behind the cooling rate control members 41a to 41f as viewed from the glass plate 90 side. The rear cooling space 422 is a portion of the cooling space 420. In the cooling space 420, the rear cooling space 422 is spaced apart from the space other than the rear cooling space 422. Specifically, both side portions of the rear cooling space 422 in the width direction of the glass sheet 90 are separated by members such as guide grooves having the same shape as the cooling rate control members 41a to 41f. Rear cooling space 422 and cooling speed control The opposite sides of the members 41a to 41f are separated by the inner wall of the forming device 400 or the heat insulating member. The upper portion and the lower portion of the rear cooling space 422 are separated by a cooler 51a and a lower partition member 60, respectively. The rear cooling space 422 is divided into a plurality of cooling chambers 422a to 422f along the traveling direction of the glass sheet 90 by the coolers 51b to 51f.

(2-4-2) End cooling device

The end portion cooling device 42 is a unit that cools both end portions of the glass sheet 90 in the width direction in the cooling space 420. As shown in FIG. 2, the end portion cooling device 42 is disposed at a position opposite to both surfaces of the glass sheet 90 at both end portions 90b in the width direction of the glass sheet 90. The end portion cooling device 42 is provided on both sides of the cooling rate control members 41a to 41f in the width direction of the glass sheet 90. Further, as shown in FIG. 2, a plurality of end cooling devices 42 are provided along the downward flow direction of the glass sheet 90.

Figure 6 is an external view of the end cooling device 42. The end cooling device 42 mainly includes a water-cooling plate 42a, a water supply pipe 42b, and a drain pipe 42c. The water-cooling plate 42a is composed of a member having high thermal conductivity, excellent oxidation resistance, and heat resistance. In the present embodiment, the water-cooling plate 42a is formed of stainless steel. The water-cooling plate 42a has a flow path through which cooling water flows. The water supply pipe 42b and the drain pipe 42c communicate with the flow path of the water-cooling plate 42a. The water-cooling plate 42a has a surface corresponding to the surface of the glass plate 90. The end cooling device 42 has a configuration that is proximate or deviable relative to the glass sheet 90.

The cooling water is supplied to the flow path of the water-cooling plate 42a through the water supply pipe 42b. The cooling water heated by the flow path of the water-cooling plate 42a is discharged from the drain pipe 42c. Both end portions 90b of the glass plate 90 in the width direction are cooled by radiant heat transfer from the water-cooling plate 42a.

The end portions 90b of the glass sheet 90 are cooled at a speed greater than the central portion 90a of the glass sheet 90 by the cooling rate controlling members 41a to 41f and the end portion cooling device 42. Thereby, the end portion cooling device 42 can suppress the contraction of the glass sheet 90 in the width direction, and can form a desired temperature distribution in the width direction of the glass sheet 90.

(2-4-3) Insulation member

As shown in Fig. 5, the heat retaining member 43 is fixed to the bent portion 62a on the lower side of the cooling rate controlling member 41a. That is, the heat insulating member 43 is provided in the rear cooling space 422. A plurality of heat insulating members 43 are attached to the cooling rate control member 41a along the longitudinal direction thereof. The heat insulating member 43 is at least a part of the space near the softening point in the central region 90a of the glass sheet 90, and is intermittently or irregularly arranged in the width direction of the glass sheet 90 in accordance with the wall thickness distribution shape of the glass sheet 90. Here, the vicinity of the softening point is a temperature region from the temperature at which the softening point of the glass sheet 90 is added to 100 ° C until the temperature is reduced by 100 ° C from the softening point of the glass sheet 90. In order to allow the central portion 90a in the width direction of the glass sheet 90 to face the both end portions 90b in the space where the temperature of the central portion 90a of the glass sheet 90 is lower than the softening point, the temperature of the glass sheet 90 is lowered in temperature or continuity. The heat-dissipating members 43 are arranged substantially uniformly and without gaps in the width direction of the glass sheet 90. The other cooling rate control members 41b to 41f are also provided with a plurality of heat insulating members 43 in the same manner as the cooling rate control member 41a.

The heat insulating member 43 suppresses heat dissipation from the cooling rate control members 41a to 41f. The heat insulating member 43 is, for example, a ceramic fiber board and a blanket. The thickness and warpage of the glass sheet 90 are controlled by the heat insulating member 43. For example, the temperature of the central portion 90a in the width direction of the glass sheet 90 is cooled to at least a portion of the space near the softening point, and the size of the heat insulating member 43 is appropriately adjusted, whereby the glass is controlled according to the thickness distribution of the glass sheet 90 in the width direction. The thickness of the plate 90.

Further, by using the heat insulating member 43, the temperature distribution in the width direction of the glass sheet 90 can be controlled. Thereby, the temperature distribution of the glass sheet 90 suitable for reducing the thickness deviation and warpage of the glass sheet 90 can be achieved.

Further, by appropriately adjusting the size of the heat retaining member 43, a temperature distribution in which the temperature of the glass sheet 90 is gradually reduced or continuous from the central portion 90a of the glass sheet 90 toward the both end portions 90b can be formed. Thereby, the warpage of the glass plate 90 is controlled in such a manner that the flatness is within a specific range. In order to form such a temperature distribution, for example, the heat insulating members 43 provided at the central portions in the longitudinal direction of the cooling rate controlling members 41b to 41f are formed thicker or higher than the heat insulating members 43 provided at both end portions.

(2-5) cooler

The coolers 51a to 51f are members that divide the rear cooling space 422 in the vertical direction along the traveling direction of the glass sheet 90. As shown in FIG. 3, the pair of rear cooling spaces 422 are divided into six cooling chambers 422a to 422f by five coolers 51b to 51f, respectively. The cooling chambers 422a to 422f are spaces located behind the cooling rate control members 41a to 41f as viewed from the glass plate 90 side. The cooling chamber 422a is located at the most upstream in the six cooling chambers 422a to 422f with respect to the downward flow direction of the glass sheet 90. The cooling chamber 422f is located most downstream in the six cooling chambers 422a to 422f with respect to the downward flow direction of the glass sheet 90. Further, at least a part of the cooling chambers 422a to 422f may be cooled by the coolers 51a to 51f.

As shown in Fig. 3, the cooler 51a is provided at a height position of the bent portion 62a on the upper side of the cooling rate control member 41a. The cooler 51b is provided at a height position between the cooling rate control member 41a and the cooling rate control member 41b. That is, the cooler 51b is provided at a height position between the cooling chamber 422a corresponding to the cooling rate control member 41a and the cooling chamber 422b corresponding to the cooling rate control member 41b. Similarly, the cooler 51c is provided at a height position between the cooling rate control member 41b and the cooling rate control member 41c. That is, the cooler 51c is provided at a height position between the cooling chamber 422b corresponding to the cooling rate control member 41b and the cooling chamber 422c corresponding to the cooling rate control member 41c. The other coolers 51d to 51f are also the same.

The cooling chamber 422a is surrounded by the cooling rate control member 41a, the cooler 51a, and the cooler 51b, and the cooling chamber 422b is surrounded by the cooling rate control member 41b, the cooler 51b, and the cooler 51c. The same applies to the cooling chambers 422c to 422e. The cooling chamber 422f is surrounded by the cooling rate control member 41f, the cooler 51f, and the lower partition member 60.

Each of the coolers 51a to 51f has the same configuration. Next, the configuration of the cooler 51b will be described. Furthermore, the following description also applies to the other coolers 51a, 51c to 51f. The cooler 51b mainly includes a heat insulating plate 52b, a coolant pipe 53b, and a support portion 54b. Fig. 7 is an external view of the cooler 51b as seen from below. Figure 8 is a side view of the cooler 51b.

(2-5-1) insulation board

The heat shield 52b has substantially the same length as the cooling rate control members 41a to 41f in the width direction of the glass sheet 90. The heat shield 52b suppresses heat transfer between the cooling chamber 422a and the cooling chamber 422b which are separated by the cooler 51b.

The heat shield 52b is attached to the upper portion of the cooler 51b. That is, FIG. 7 is an external view of the cooler 51b provided in the rear cooling space 422 as viewed from below. The longitudinal direction of the heat shield 52b is parallel to the longitudinal direction of the cooling rate control members 41a to 41f and the width direction of the glass sheet 90. The heat shield 52b preferably has a thickness of 0.07 m ² . Thermal resistance above K/W.

(2-5-2) coolant tube

The coolant pipe 53b is attached to the lower portion of the cooler 51b. The coolant pipe 53b is a pipe in which cooling water flows inside. The coolant pipe 53b is attached to the lower surface of the heat shield 52b. The coolant tube 53b mainly includes a plurality of angle tubes 91, a plurality of long bends 92, an inflow tube 93, and an outflow tube 94. In the present embodiment, as shown in FIG. 7, the coolant pipe 53b includes four angle pipes 91 and three long elbows 92. Further, a commercially available stainless steel pipe, a copper pipe, or the like is used for the angle pipe 91, the long elbow 92, the inflow pipe 93, and the outflow pipe 94. The angle tube 91 has a substantially square cross-sectional shape. The long elbow 92, the inflow pipe 93, and the outflow pipe 94 have a substantially circular cross-sectional shape.

The four corner pipes 91 are attached to the lower surface of the heat insulating plate 52b along the longitudinal direction of the heat insulating plate 52b. The four corner tubes 91 are disposed in parallel with each other with a predetermined interval therebetween. The interval between the adjacent corner tubes 91 is equal to or larger than the outer diameter of the angle tube 91. As shown in Fig. 7, the long elbow 92 is a U-shaped tube that connects the ends of the adjacent corner tubes 91 to each other. The inflow pipe 93 and the outflow pipe 94 are connected to the end portions of the two corner pipes 91 provided at both ends of the heat insulating plate 52b. The two corner pipes 91 that are not connected to the inflow pipe 93 and the outflow pipe 94 are connected to the two corner pipes 91 that are different from each other at the both end portions by the long elbow 92. The cross-sectional area of the long elbow 92 is substantially equal to the cross-sectional area of the inflow pipe 93 and the outflow pipe 94. The sectional area of the angle tube 91 is less than four times the sectional area of the inflow tube 93 and the outflow tube 94.

The water flowing inside the coolant pipe 53b is supplied from the inflow pipe 93, alternately flows in the angle pipe 91 and the long elbow 92, and is discharged from the outflow pipe 94. As shown in Figure 7, inside the coolant tube 53b The flowing water is reciprocated a plurality of times in the longitudinal direction of the heat insulating plate 52b.

(2-5-3) Support

The support portion 54b is attached to both side portions of the cooler 51b. The pair of support portions 54b are respectively coupled to the end portions of the four corner tubes 91. As shown in FIG. 8, the angle tube 91 is fixed to the support portion 54b by the heat conductive cement 96. As shown in FIG. 8, the upper end faces of the four angle tubes 91 are included in the tube plane 95. The tube plane 95 is a virtual plane containing the upper end faces of the four angle tubes 91. The tube plane 95 is a plane parallel to the lower surface of the heat shield 52b. The heat insulating plate 52b is supported by the upper end faces of the four corner pipes 91 by its own weight in a state of being in contact with the pipe plane 95. That is, the upper end faces of the four corner pipes 91 are in contact with the lower surface of the heat insulating plate 52b.

The support portion 54b is fixed to a wall surface constituting the cooling space 420. The cooler 51b is provided in the rear cooling space 422 in a state where both end portions thereof are supported by the pair of support portions 54b. The cooler 51b has a rigidity in which the amount of deformation due to the self-weight of the central portion in the longitudinal direction is 20 mm or less.

(2-6) lower spacer member

The lower partition member 60 is a plate-shaped heat insulating member provided below the cooling unit 40. As shown in FIG. 3, the lower partition members 60 are provided on both sides in the thickness direction of the glass sheet 90. The lower partition member 60 partitions the cooling space 420 from the slow cooling space 430 below the cooling space 420 in the vertical direction. The lower spacer member 60 blocks thermal movement from the cooling space 420 to the slow cooling space 430.

(2-7) Pull down roller

As shown in FIGS. 2 and 3, the pull-down drum 70 is provided in the slow cooling space 430 for pulling down the glass plate 90. The slow cooling space 430 is a space in which the glass plate 90 is gradually cooled while being pulled down by the pull-down drum 70. The pull-down rollers 70 are provided on both sides in the thickness direction of the glass sheet 90 and at both end portions in the width direction of the glass sheet 90. The pull-down drum 70 is rotated by a motor drive. The glass plate 90 is pulled down by the rotation of the pull-down drum 70.

The temperature of the central region 90a of the glass plate 90 reaches the average of the glass plates 90 before the slow cooling point. The cooling rate is greater than the average cooling rate of the glass sheet 90 before the temperature of the central region 90a of the glass sheet 90 reaches a temperature 50 ° C lower than the strain point from the slow cooling point. The space in which the temperature of the central portion 90a of the glass plate 90 is cooled to the slow cooling point is the cooling space 420. The space in which the temperature of the central portion 90a of the glass plate 90 is cooled from the slow cooling point to a temperature 50 ° C lower than the strain point is a part of the space of the slow cooling space 430.

(2-8) Control device

The control device mainly includes a CPU, a RAM, a ROM, a hard disk, and the like. The control device is connected to the cooling drum 30, the end portion cooling device 42, the coolers 51a to 51f, the pull-down drum 70, and the like. The control device adjusts, for example, the rotational speeds of the cooling drum 30 and the pull-down drum 70. The control device adjusts, for example, the flow rate of the cooling water passing through the water-cooling plate 42a of the end cooling device 42. The control means adjusts, for example, the flow rate of the cooling water passing through the coolant pipe 53a of the cooler 51a.

(3) Action of the glass substrate manufacturing apparatus

The molten glass 80 overflowing from the groove 12 of the molded body 10 flows down the both sides of the formed body 10, and merges near the lower end of the formed body 10. The molten glass 80 after the merging becomes the glass plate 90. The glass plate 90 is continuously formed, and is cooled while flowing down in the cooling space 420 and the slow cooling space 430.

In the cooling space 420, first, both ends of the glass plate 90 in the width direction are rapidly cooled by the cooling drum 30. Next, the cooling unit 40 is used to adjust the cooling rate of the glass sheet 90 to cool the glass sheet 90 to the vicinity of the slow cooling point. In the slow cooling space 430, the glass sheet 90 is gradually cooled while being pulled down by the pull-down drum 70. The cooled glass sheet 90 is cut into a specific size to obtain a glass substrate of the product size.

(4) Characteristics of the glass substrate manufacturing apparatus

(4-1)

In the cooler 51b of the present embodiment (the same applies to the other coolers 51a and 51c to 51f, the sectional area of the angle tube 91 is not four times the sectional area of the long elbow 92, the inflow pipe 93, and the outflow pipe 94. , at the joint between the inflow pipe 93 and the angle pipe 91, the angle pipe 91 and the long elbow 92 The connection portion and the connection portion between the angle tube 91 and the outflow pipe 94 are controlled so that the rate of change of the flow path sectional area of the coolant pipe 53b is less than a specific value. In other words, the entire flow path of the coolant pipe 53b does not have a portion where the flow path sectional area is abruptly enlarged, and a portion where the flow path sectional area is sharply reduced.

When the coolant pipe in which the liquid coolant for heat exchange flows has a portion in which the cross-sectional area of the flow path changes abruptly, the inside of the coolant pipe generates a portion where the flow of the coolant stagnate. In the portion where the coolant is stopped, the heat exchange efficiency of the coolant flowing through the coolant pipe and the atmosphere around the coolant pipe is lowered. Further, when the cleanliness of the coolant is low, the impurities contained in the coolant may precipitate and accumulate in the portion where the coolant is stopped, which may cause the coolant tube to clog. Further, when the shape of the flow path of the coolant pipe is complicated such as a sudden change in the cross-sectional area of the flow path, the air inside the coolant pipe may not be completely removed when the coolant is filled with the coolant. Thereby, the wall surface of the coolant tube which is not in contact with the coolant is locally heated and oxidized, which may cause breakage.

In the present embodiment, as described above, the coolant pipe 53b does not have a portion in which the cross-sectional area of the flow path abruptly changes, and the occurrence of the portion where the coolant is stopped can be suppressed. Therefore, the efficiency of heat exchange between the coolant flowing inside the coolant pipe 53b and the atmosphere around the coolant pipe 53b is suppressed, and the coolant pipe 53b is prevented from being clogged by impurities contained in the coolant. Further, since the portion where the air is trapped inside the coolant pipe 53b is suppressed, it is possible to suppress the wall surface of the coolant pipe 53b from being locally heated and damaged.

Therefore, since the coolers 51a to 51f of the present embodiment can suppress a decrease in heat exchange efficiency, the glass substrate manufacturing apparatus 100 including the coolers 51a to 51f can effectively perform the cooling space 420 for cooling the formed glass sheet 90. Heat exchange with the glass plate 90.

(4-2)

In the cooler 51b of the present embodiment, the upper end faces of the four corner pipes 91 constituting the coolant pipe 53b are included in the same pipe plane 95. The heat shield 52b is supported by four angle tubes 91. The heat shield 52b separates the cooling chamber 422a above the cooler 51b from the cooling chamber 422b below the cooler 51b. Therefore, no gas movement occurs between the cooling chamber 422a and the cooling chamber 422b, And block the heat movement.

Thereby, heat exchange between the coolant pipe 53b attached to the lower surface of the heat insulating plate 52b and the atmosphere of the cooling chamber 422b below the cooler 51b is performed. On the other hand, heat exchange between the coolant pipe 53b and the atmosphere of the cooling chamber 422a above the cooler 51b is suppressed by the heat insulating plate 52b. That is, the cooler 51b can adjust the temperature of the cooling rate control member 41b that is in contact with the cooling chamber 422b without affecting the temperature of the cooling rate control member 41a that is in contact with the cooling chamber 422a.

Therefore, the coolers 51a to 51f can adjust only the temperatures of the cooling rate control members 41a to 41f, respectively. Thereby, the temperature of each of the cooling rate control members 41a to 41f can be independently adjusted by, for example, controlling the flow rate of the coolant passing through the respective coolers 51a to 51f by using the control device.

Therefore, the coolers 51a to 51f of the present embodiment can efficiently exchange heat with the glass sheet 90 via the cooling rate control members 41a to 41f. Thereby, the coolers 51a to 51f can appropriately control the cooling rate of the glass plate 90.

(4-3)

In the cooler 51b of the present embodiment, the four angle tubes 91 are arranged in parallel with each other with a space therebetween. The upper end faces of the respective corner tubes 91 are bonded to the lower surface of the heat insulating plate 52b. Therefore, the three faces other than the upper end faces of the respective corner pipes 91 of the cooler 51b contact the atmosphere of the cooling chamber 422b. Thus, by arranging the four corner pipes 91 at intervals, the surface area of the angle pipe 91 that is in contact with the cooling chamber 422b is large, so that the heat exchange efficiency of the cooler 51b is improved.

Therefore, since the coolers 51a to 51f of the present embodiment have high heat exchange efficiency, the glass substrate manufacturing apparatus 100 including the coolers 51a to 51f can efficiently heat the glass sheet 90 in the cooling space 420 that cools the glass sheet 90. exchange. Further, by arranging the four corner tubes 91 at intervals, the weight of the cooler 51b can be reduced.

(4-4)

In the cooler 51b of the present embodiment, the corner pipe 91 occupying most of the flow path of the coolant pipe 53b is attached to the lower surface of the heat insulating plate 52b, and as shown in Fig. 8, only the long elbow is shown. 92. The inflow pipe 93 and the outflow pipe 94 protrude downward from the lower end surface of the angle pipe 91. The long elbow 92, the inflow pipe 93, and the outflow pipe 94 are coupled to the end of the angle pipe 91. Therefore, the height dimension of the cooler 51b is controlled within the value obtained by combining the height dimension of the heat insulating plate 52b and the height dimension of the angle tube 91 except for both end portions in the longitudinal direction of the cooler 51b.

Therefore, the coolers 51a to 51f of the present embodiment can control the height dimension except for the both end portions in the longitudinal direction. Therefore, when the height of the cooling space 420 is limited, a plurality of coolers 51a to 51f can be provided without lowering the heat exchange efficiency.

(4-5)

In the cooler 51b of the present embodiment, a commercially available stainless steel pipe, a copper pipe, or the like is used for the angle pipe 91, the long elbow 92, the inflow pipe 93, and the outflow pipe 94 that constitute the coolant pipe 53b. Further, in order to assemble the coolant tube 53b, the connection portion between the angle tube 91 and the long elbow 92, the connection portion between the angle tube 91 and the inflow tube 93, and the connection portion between the angle tube 91 and the outflow tube 94 may be welded to the entire circumference.

Therefore, since the coolers 51a to 51f of the present embodiment are provided with the coolant pipe 53b having a simple structure, the man-hour and cost for assembling the coolant pipe 53b can be suppressed.

(4-6)

In the cooler 51b of the present embodiment, both end portions of the angle tube 91 are fixed to the pair of support portions 54b by the heat conductive cement 96. The heat conductive cement 96 has high thermal conductivity, and therefore, the support portion 54b is easily cooled by the coolant flowing inside the angle tube 91.

One end of the support portion 54b is located in the vicinity of the cooling rate control member 41b, and thus is easily heated by the heat of the glass plate 90 flowing down. When the support portion 54b is heated and oxidized, damage and thermal deformation of the support portion 54b may occur.

In the present embodiment, the support portion 54b is easily cooled by the coolant flowing inside the angle tube 91, so that damage and thermal deformation of the support portion 54b can be suppressed.

(4-7)

The cooler 51b of the present embodiment is provided in a state in which both end portions are supported by a pair of support portions 54b. The cooler 51b has a dimension irrespective of its length direction due to its length The amount of deformation caused by the self-weight of the central portion is 20 mm or less. Therefore, even in a state where only the both end portions of the cooler 51b are supported by the pair of support portions 54b, the central portion of the cooler 51b does not substantially hang down due to its own weight. That is, the central portion of the cooler 51b need not be supported by other support members.

Therefore, the central portion of the cooler 51b in the longitudinal direction does not need to be supported by other supporting members, so that the decrease in heat exchange efficiency can be suppressed. Further, the cooler 51b does not interfere with the access to the space in the vicinity of the central portion in the longitudinal direction. Therefore, the cooling space 422 provided with the cooler 51b can be effectively utilized in the longitudinal direction of the cooler 51b.

(4-8)

In the glass substrate manufacturing apparatus 100 of the present embodiment, a plurality of cooling rate control members 41a to 41f are provided in the cooling space 420 in the downward direction of the glass sheet 90. The cooling rate control members 41a to 41f are in contact with the cooling chambers 422a to 422f, respectively. The cooling chambers 422a to 422f are cooled by the coolers 51a to 51f, respectively. That is, the coolers 51a to 51f adjust the temperatures of the cooling rate control members 41a to 41f, respectively. Thereby, it is possible to control the cooling rate of the glass plate 90 which is cooled while flowing down.

In the conventional glass substrate manufacturing apparatus, for example, in order to rapidly cool the glass sheet which has just been separated from the lower end of the molded body, the cooling gas is blown to the cooling rate control member to adjust the temperature of the glass sheet. However, in this method, the temperature difference between the glass sheets is caused by the difference in the fine flow rate of the gas blown to the cooling rate control member in the width direction of the glass sheet, so that it is difficult to adjust the temperature of the glass sheet. Further, a part of the gas blown to the cooling rate control member accidentally leaks and collides with the glass sheet, which may cause a temperature difference between the glass sheets. Therefore, in this method, it is difficult to adjust the cooling rate of the glass sheet, so there is a problem that the sheet thickness variation of the glass sheet increases.

In the glass substrate manufacturing apparatus 100 of the present embodiment, the temperatures of the cooling rate control members 41a to 41f can be independently adjusted by the coolers 51a to 51f, respectively. Therefore, the coolers 51a to 51f can easily adjust the cooling rate of the glass sheet 90 along the downward direction of the glass sheet 90. Set the desired value. Therefore, the glass substrate manufacturing apparatus 100 can efficiently mass-produce the glass sheet 90 without increasing the sheet thickness deviation of the glass sheet 90.

(5) Variations

(5-1) Change A

In the cooler 51b of the present embodiment (the same applies to the other coolers 51a and 51c to 51f, the angle tube 91 through which the coolant for heat exchange flows is a tube having a substantially square cross-sectional shape). However, instead of the angle tube 91, a circular tube having a substantially circular cross-sectional shape may be used.

Fig. 9 and Fig. 10 show a cooler 151b which is a modification of the cooler 51b of the present embodiment. Figure 9 is a plan view of the cooler 151b. Figure 10 is a side view of the cooler 151b. The cooler 151b mainly includes a heat insulating plate 152b, a coolant pipe 153b, and a support portion 154b. Further, the cooler 151b is disposed at the same position as the cooler 51b of the present embodiment, and has the same effect.

The heat insulating plate 152b and the support portion 154b of the cooler 151b have the same configuration as the heat insulating plate 52b and the support portion 54b of the cooler 51b of the present embodiment. The coolant pipe 153b of the cooler 151b has a configuration different from that of the coolant pipe 53b of the cooler 51b of the present embodiment. As shown in FIG. 9, the coolant pipe 153b includes four circular pipes 191, three long elbows 192, an inflow pipe 193, and an outflow pipe 194. The cross-sectional area of the circular tube 191 is substantially the same as the cross-sectional area of the long elbow 192, the inflow tube 193, and the outflow tube 194. The long elbow 192, the inflow pipe 193, and the outflow pipe 194 are fixed to the support portion 154b by the heat conductive cement 196.

The four circular tubes 191 are arranged in parallel with each other with a space therebetween. The upper ends of the respective round tubes 191 are bonded to the lower surface of the heat insulating plate 152b. The inflow pipe 193 and the outflow pipe 194 are connected to the end portions of the two circular pipes 191 provided at both ends of the heat insulating plate 152b. The two round pipes 191 which are not connected to the inflow pipe 193 and the outflow pipe 194 are connected to the two round pipes 191 which are different from each other at the both end portions by the long elbow 192.

In the present variation, as shown in FIG. 10, the long elbow 192 and the inflow pipe 193 are disposed in The round tube 191 is at the same height position. The portion of the outflow pipe 194 other than the joint portion with the round pipe 191 is located at a lower height than the pipe 191.

The cooling water flowing inside the coolant pipe 153b flows in from the inflow pipe 193, alternately flows in the circular pipe 191 and the long elbow 192, and flows out from the outflow pipe 194. As shown in Fig. 9, the cooling water flowing inside the coolant pipe 153b is reciprocated a plurality of times in the longitudinal direction of the heat insulating plate 152b.

In the present modification, the coolant tube 153b of the cooler 151b has a circular tube 191. The bonding area between the round pipe 191 and the heat insulating plate 152b is smaller than that of the angle pipe 91 of the present embodiment. However, the configuration is such that the four circular tubes 191 are arranged at intervals, and the surface area of the circular tube 191 which is in contact with the cooling chamber below the heat insulating plate 152b is large. Therefore, the cooler 151b has high heat exchange efficiency similarly to the cooler 51b of the present embodiment.

(5-2) Change B

In the cooler 51b of the present embodiment, the coolant tubes 53b are disposed so as to be reciprocated a plurality of times at intervals. Specifically, the coolant flowing inside the coolant pipe 53b passes through the four angle pipes 91, thereby reciprocating twice along the longitudinal direction of the heat insulating plate 52b. However, the number of round trips of the coolant pipe 53b can be appropriately changed depending on the sectional area of the angle pipe 91 and the size of the heat insulating plate 52b.

Further, the sectional area of the angle tube 91 can be appropriately changed. In the present embodiment, the sectional area of the angle tube 91 is less than four times the sectional area of the inflow tube 93 and the outflow tube 94. However, the sectional area of the angle tube 91 is preferably substantially the same as the sectional area of the inflow tube 93 and the outflow tube 94. Thereby, the rate of change in the cross-sectional area of the flow path of the coolant tube 53b such as the connection portion between the angle tube 91 and the inflow pipe 93 can be suppressed, and it is more difficult to generate a portion where the flow of the coolant is stagnant.

(5-3) Change C

In the cooler 51b of the present embodiment, the angle tube 91 of the coolant pipe 53b is formed of a stainless steel pipe, a copper pipe or the like. The three faces other than the upper end surface of the angle tube 91 contact the atmosphere of the cooling chamber 422b. Therefore, it is also possible to apply a high emissivity coating on three faces other than the upper end surface of the corner tube 91. material. Thereby, the absorption rate of the heat radiation of the angle tube 91 is increased, so that the heat exchange efficiency between the coolant flowing inside the angle tube 91 and the atmosphere of the cooling chamber 422b is improved.

Further, the surface of the angle tube 91 may be subjected to sandblasting before applying the high emissivity coating to the surface of the angle tube 91. Thereby, the adhesion of the high emissivity paint on the surface of the corner tube 91 is improved.

(5-4) Variation D

In the cooler 51b of the present embodiment, the coolant pipe 53b has four angle pipes 91. However, the angle tube 91 in which the four corner tubes 91 are located near the heat source and is easily heated can also be replaced with the round tube 191 of "Variation A". Specifically, the angle tube 91 located at the position closest to the cooling rate control members 41a to 41f may be replaced with the round tube 191.

The angle tube 91 located at the position closest to the cooling rate control members 41a to 41f is opposite to the surface facing the cooling rate control members 41a to 41f and the surface opposite to the opposite surface. The difference in heat received by heat conduction from heat radiation is large. Therefore, the angle tube 91 generates a large temperature difference depending on the surface thereof, and therefore, due to the thermal deformation caused by the temperature difference, the corner portion of the angle tube 91 may generate a large stress. Thereby, the angle tube 91 may be damaged. Therefore, the angle tube 91 located at a position close to the heat source is preferably replaced with the round tube 191.

(5-5) Change E

In the present embodiment, pure nickel is used as the material of the cooling rate controlling members 41a to 41f, but other materials having high thermal conductivity such as molybdenum, sintered SiC, recrystallized SiC, artificial graphite, iron, and tungsten may be used.

However, molybdenum is preferably used in a non-oxidizing atmosphere. Further, when molybdenum is used in an oxidizing atmosphere, it is preferred to apply oxidation-resistant coating to the cooling rate controlling members 41a to 41f. Further, sintered SiC and recrystallized SiC can be used in an oxidizing atmosphere, and artificial graphite, iron, and tungsten can be used in a non-oxidizing atmosphere.

(5-6) Variation F

In the present embodiment, the cooling rate control members 41a to 41f use guide grooves (groove steel), but metal members having other shapes may be used. In this case, it is preferable that the cooling rate control members 41a to 41f adjacent to each other in the vertical direction are in minimum contact with each other, thereby suppressing heat conduction between the adjacent cooling rate control members 41a to 41f.

(5-7) Change G

In the glass substrate manufacturing apparatus 100 for cooling the glass sheet 90 having a length of 2200 mm in the width direction, the length of the cooling rate control members 41a to 41f in the longitudinal direction and the cooling rate control member 41a are exemplified. The number of ~41f. However, the length of the cooling rate control members 41a to 41f in the longitudinal direction and the number of the cooling rate control members 41a to 41f may be changed in accordance with the length and thickness of the glass sheet 90 manufactured by the glass substrate manufacturing apparatus 100 in the width direction.

(5-8) Change H

In the present embodiment, the main portion 63a of the cooling rate control member 41a extends in the vertical direction. However, for example, the concave portion may be formed to be inclined with respect to the vertical direction or in the vertical direction. Thereby, the ascending air current generated along the surface of the glass plate 90 can be suppressed, and the difference in the cooling rate of the glass plate 90 in the vertical direction can be suppressed. Therefore, in the present modification, the glass sheet 90 is cooled at a substantially constant speed in the cooling space 420.

(5-9) Change Example I

In the present embodiment, the rear cooling space 422 is divided into six cooling chambers 422a to 422f along the traveling direction of the glass sheet 90 by the five coolers 51b to 51f. However, as long as at least a part of the rear cooling space 422 is divided by the coolers 51a to 51f, it may be divided by another heat insulating member or the like.

(5-10) Variation J

In the present embodiment, the cooling chambers 422a to 422f are cooled by the coolers 51a to 51f, respectively. However, if at least a part of the cooling chambers 422a to 422f are cooled by the coolers 51a to 51f, for example, a configuration different from the coolers 51a to 51f of the present embodiment may be used. The cooler and other cooling devices are used for cooling.

51b‧‧‧cooler

52b‧‧‧insulation board

53b‧‧‧ coolant tube

54b‧‧‧Support

91‧‧‧Corner tube

92‧‧‧Long elbow

93‧‧‧Inflow pipe

94‧‧‧Outflow tube

Claims (10)

A method for producing a glass substrate, comprising: a molding step of forming a glass plate by overflowing molten glass from a molded body; and a cooling step of cooling the formed glass plate while being elongated downward; And a cutting step of cutting the glass plate after cooling to obtain a glass substrate; and cooling the glass plate separated from the molded body to at least a portion of a space near a slow cooling point; a cooling rate control member facing the surface of the central portion in the width direction of the plate is located on the opposite side of the glass plate via the cooling rate control member, and the cooling space includes a cooling chamber disposed along the traveling direction of the glass plate. At least a part of the cooling chamber is cooled by a cooler, and in the cooling step, the glass plate moves in a direction along the traveling direction with respect to the cooling rate control member contacting the cooling chamber, thereby gradual or continuous The ground is cooled, and at least a portion of the cooler includes: a heat shield that suppresses the cooling chamber and The traveling direction of the heat transfer between the adjacent space of the cooling chamber of movement; and a coolant pipe, by which the flow of liquid coolant inside the cooling chamber and cooling. The method for producing a glass substrate according to claim 1, wherein the cooling step comprises: a first cooling step of performing the glass sheet at a first average cooling rate before the temperature in the central region of the glass sheet reaches a slow cooling point. Cooling; and a second cooling step of slowing down the temperature in the central region of the glass sheet The glass plate is cooled at a second average cooling rate before the cold spot reaches a temperature 50 ° C lower than the strain point; and the first average cooling rate is greater than the second average cooling rate. The method of producing a glass substrate according to claim 1 or 2, wherein in the cooling step, the cooling rate control member controls the cooling rate of the glass sheet in the traveling direction. The method for producing a glass substrate according to claim 1 or 2, wherein an end portion cooling device for cooling an end portion of the glass sheet in the width direction is provided in a space for cooling the glass sheet separated from the molded body In the cooling step, the glass plate is cooled by cooling the end portion of the glass sheet at a speed greater than the central portion of the glass sheet by the end portion cooling device. The method for producing a glass substrate according to claim 1 or 2, wherein a heat insulating member is provided along a width direction of the glass sheet on a surface of the cooling rate control member opposite to a facing surface of the glass sheet. In the cooling step, the thickness and/or warpage of the glass sheet in the width direction is controlled by the heat insulating member. The method for producing a glass substrate according to claim 5, wherein in the cooling step, at least a part of a space in the central region of the glass sheet reaching a softening point is changed by changing a size of the heat insulating member The thickness distribution of the glass sheet in the width direction controls the thickness of the glass sheet. The method for producing a glass substrate according to claim 6, wherein in the cooling step, after controlling the thickness of the glass plate, the size of the heat insulating member is changed to form the central portion from the glass plate toward the end portion. The temperature distribution in which the temperature of the glass sheet is lowered in stages or continuously, and the warpage of the glass sheet is controlled in such a manner that the flatness is within a specific range. A cooler for cooling a space, the cooler comprising: a heat insulation panel dividing the space into a plurality of cooling chambers and suppressing heat transfer between the adjacent cooling chambers; and a coolant A tube that cools the cooling chamber by internal flowing liquid coolant. The cooler of claim 8, wherein the coolant tubes are disposed in a plurality of times spaced apart from each other at an interval above the outer diameter thereof, and formed as a tube plane including a plane of the coolant tubes to and from the air, the heat insulation The plate constitutes one of the inner surfaces of the cooling chamber, and is disposed on the row of the coolant tubes by its own weight while being parallel to the tube plane and contacting the tube plane. The cooler according to claim 8 or 9, wherein the cooler has a rigidity such that the deformation amount due to the self weight of the central portion in the longitudinal direction is not related to the length in the longitudinal direction in a state where both end portions are supported 20mm or less.