JP5132012B2 - Glass sheet manufacturing apparatus, glass sheet manufacturing method, and molded body - Google Patents

Description

  The present invention relates to a glass sheet manufacturing apparatus, a glass sheet manufacturing method, and a molded body.

  Conventionally, an overflow / down-draw method is used as one of glass sheet manufacturing methods. In the overflow downdraw method, a glass sheet is continuously produced by joining molten glass that has been overflowed and shunted from a molded body at the lower end of the molded body.

  In general, in a glass sheet manufacturing process using an overflow downdraw method, the molded body has a pair of inclined surfaces on which the overflowed molten glass flows down. These inclined surfaces are connected to each other at the lower end of the molded body. Ideally, it is desirable that the pair of molten glass flowing down the inclined surface is joined and fused at the lower end of the molded body without leaving the surface of the molded body. However, depending on the glass viscosity at the lower end of the molded body, the molten glass flowing down the inclined surface may be separated from the surface of the molded body before reaching the lower end of the molded body. A pair of molten glass once separated from the surface of the molded body is bonded again if the viscosity required for the merging surface to be fused is maintained at the merging point located below the lower end of the molded body, A glass sheet is formed.

  In the glass sheet manufacturing process by the overflow / down-draw method, the molten glass separated from the molded body comes into contact with low-temperature air, so that the viscosity increases in a short time. If the viscosity of the molten glass rises too much, the molten glass does not fuse well at the joining point, and cracks and the like occur in the formed glass sheet, so that stable operation cannot be performed. In particular, at the end of the molded body, the viscosity of the molten glass rises due to the large area in contact with the external air and the low temperature rising airflow from the cooling device installed below. For this reason, the molten glass flowing down the surface of the molded body tends to increase in viscosity at the end of the molded body and easily separate from the surface of the molded body. As the molten glass is further away from the molded body, the temperature of the molten glass separated from the molded body is further lowered and the viscosity is further increased, so that the bonding of the molten glass at the joining point is deteriorated. As a result, the molded glass sheet may be cracked.

  Patent Document 1 (Japanese Unexamined Patent Application Publication No. 2009-518275) discloses a molded body having a sharp bottom end and embedded with a conductive member. Since this molded body has a sharp lower end, the lower end tends to be partially lost. Depending on the degree, the partially-deleted molded body may cause a defective shape of the glass and thus cannot be practically used.

  Moreover, in the molded object currently disclosed by patent document 1, the temperature of the molten glass which flows down the surface of a molded object is controlled by heating the embedded electroconductive member, and a molten glass is from the surface of a molded object. It can be prevented from leaving. However, in the case of a molded body made of refractory, it is technically difficult to join the conductive member to the lower end of the molded body.

  The present invention is provided with a molded body with a low risk of partial defects, and a glass sheet production apparatus capable of producing a glass sheet that is less likely to have a defective shape at the end, using a molded body with a low risk of partial defects, And the glass sheet manufacturing method which can manufacture the glass sheet which does not produce the shape defect of an edge part easily, and the molded object which can manufacture the glass sheet which is low in the risk of a partial defect, and is difficult to generate | occur | produce the shape defect of an edge part. The purpose is to provide.

  The glass sheet manufacturing apparatus according to the present invention is a glass sheet manufacturing apparatus provided with a molded body for forming a glass sheet by diverting molten glass to flow down and then fusing it in the vicinity of the lower end portion. The molded body has a first inclined surface, a second inclined surface, a third inclined surface, a first arc surface, and a second arc surface. A 1st inclined surface is a pair of inclined surface which inclines so that it may mutually approach toward the downward direction in the center part in the longitudinal direction of a molded object. A 2nd inclined surface is a pair of inclined surface which inclines so that it may mutually approach toward the downward direction in the both ends in the longitudinal direction of a molded object. The second inclined surface is inclined at the same angle as the first inclined surface. The third inclined surfaces are a pair of inclined surfaces that are connected to the lower ends of the second inclined surfaces at both ends in the longitudinal direction of the molded body and are inclined so as to approach each other downward. The third inclined surface is inclined at an angle closer to the horizontal than the second inclined surface. The first arc surface is an arc that is connected to the lower end of the first inclined surface at the center in the longitudinal direction of the molded body and has a cross-sectional shape in the short direction that is vertically downward. The second arc surface is an arc that is connected to the lower end of the third inclined surface at both end portions in the longitudinal direction of the molded body, and has a cross-sectional shape in the short direction that is vertically downward. The length of the second arc surface in the short direction is shorter than the length of the first arc surface in the short direction.

  A glass sheet manufacturing apparatus using an overflow downdraw method includes a molded body for forming a glass sheet by overflowing and diverting molten glass and then fusing it. Generally, at both ends in the longitudinal direction of the molded body, the viscosity is likely to increase due to the large area in contact with the external air and the low temperature rising air flow from the cooling device installed below. Therefore, the molten glass flowing down at both ends in the longitudinal direction of the molded body is easily separated from the surface of the molded body.

  The glass sheet manufacturing apparatus according to the present invention moves the point at which the molten glass is separated as far downward as possible in both longitudinal ends of the molded body from which the molten glass is easily separated. Thereby, fusion | melting of a molten glass can be performed smoothly in the vicinity of the lower end of the molded object where a pair of molten glass which flows down merges. This effect is realized only by the shape of the molded body. Therefore, the glass sheet manufacturing apparatus according to the present invention can prevent a defective shape of the glass sheet without adding a new apparatus.

  The point at which the molten glass is separated from the surface of the molded body is the viscosity of the molten glass flowing down the surface of the molded body (or the interfacial tension acting between the molten glass and the surface of the molded body at the viscosity), the melting point. It is considered to be determined by three factors: the magnitude of the force that pulls the molten glass attached vertically downward, and the angle formed by the tangent at the point on the arc of the cross section of the first arc surface and the second arc surface. .

  The glass sheet manufacturing apparatus according to the present invention preferably further includes a cooling roller. A cooling roller hold | maintains the both ends of the width direction of the glass sheet shape | molded by the molded object. The cooling roller is disposed vertically below the boundary line between the center portion and both end portions in the longitudinal direction of the molded body. In this case, the molten glass that has flowed down the boundary line between the central portion and both end portions in the longitudinal direction of the formed body becomes both ends in the width direction of the glass sheet after leaving the surface of the formed body. Both ends in the width direction of the glass sheet are later cut and removed.

  In the glass sheet manufacturing apparatus according to the present invention, the radius of the arc of the cross section of the second arc surface in the short direction of the formed body is equal to or less than the radius of the arc of the cross section of the first arc surface in the short direction of the formed body. Is preferred.

  In the glass sheet manufacturing apparatus according to the present invention, the molded body is preferably a refractory.

  The glass sheet manufacturing method according to the present invention is a glass sheet manufacturing method using a molded body for forming a glass sheet by diverting molten glass to flow down and then fusing it in the vicinity of the lower end portion. The molded body has a first inclined surface, a second inclined surface, a third inclined surface, a first arc surface, and a second arc surface. A 1st inclined surface is a pair of inclined surface which inclines so that it may mutually approach toward the downward direction in the center part in the longitudinal direction of a molded object. A 2nd inclined surface is a pair of inclined surface which inclines so that it may mutually approach toward the downward direction in the both ends in the longitudinal direction of a molded object. The second inclined surface is inclined at the same angle as the first inclined surface. The third inclined surfaces are a pair of inclined surfaces that are connected to the lower ends of the second inclined surfaces at both ends in the longitudinal direction of the molded body and are inclined so as to approach each other downward. The third inclined surface is inclined at an angle closer to the horizontal than the second inclined surface. The first arc surface is an arc that is connected to the lower end of the first inclined surface at the center in the longitudinal direction of the molded body and has a cross-sectional shape in the short direction that is vertically downward. The second arc surface is an arc that is connected to the lower end of the third inclined surface at both end portions in the longitudinal direction of the molded body, and has a cross-sectional shape in the short direction that is vertically downward. The length of the second arc surface in the short direction is shorter than the length of the first arc surface in the short direction.

  The molded body according to the present invention has a first inclined surface, a second inclined surface, a third inclined surface, a first arc surface, and a second arc surface. A 1st inclined surface is a pair of inclined surface which inclines so that it may mutually approach toward the downward direction in the center part in the longitudinal direction of a molded object. A 2nd inclined surface is a pair of inclined surface which inclines so that it may mutually approach toward the downward direction in the both ends in the longitudinal direction of a molded object. The second inclined surface is inclined at the same angle as the first inclined surface. The third inclined surfaces are a pair of inclined surfaces that are connected to the lower ends of the second inclined surfaces at both ends in the longitudinal direction of the molded body and are inclined so as to approach each other downward. The third inclined surface is inclined at an angle closer to the horizontal than the second inclined surface. The first arc surface is an arc that is connected to the lower end of the first inclined surface at the center in the longitudinal direction of the molded body and has a cross-sectional shape in the short direction that is vertically downward. The second arc surface is an arc that is connected to the lower end of the third inclined surface at both end portions in the longitudinal direction of the molded body, and has a cross-sectional shape in the short direction that is vertically downward. The length of the second arc surface in the short direction is shorter than the length of the first arc surface in the short direction.

  The glass sheet manufacturing apparatus, the glass sheet manufacturing method, and the molded body according to the present invention can manufacture a glass sheet that has a low risk of partial defect of the molded body and is less likely to have a defective shape at the end.

It is a whole block diagram of the glass sheet manufacturing apparatus which concerns on this embodiment. It is a side view of the shaping | molding apparatus which concerns on this embodiment. It is sectional drawing of the shaping | molding apparatus which concerns on this embodiment. It is a side view of the molded object which concerns on this embodiment. It is sectional drawing in the center part of the molded object which concerns on this embodiment. It is sectional drawing in the both ends of the molded object which concerns on this embodiment. It is the figure which piled up sectional drawing in a central part, and sectional drawing in both ends of a fabrication object concerning this embodiment. In this embodiment, it is a figure showing the relationship between the interfacial tension between a molten glass and a circular arc surface, and the tensile force of a molten glass. It is an enlarged view of sectional drawing of the molded object shown by FIG. It is an expanded sectional view in the center part of the forming object concerning this embodiment. It is an expanded sectional view in the both ends of the forming object concerning this embodiment. It is the figure which piled up the expanded sectional view in the center part, and the expanded sectional view in both ends of the molded object which concerns on the modification of this embodiment.

(1) Structure of glass sheet manufacturing apparatus The whole structure of the glass sheet manufacturing apparatus 100 which concerns on embodiment of this invention is demonstrated, referring FIG. The glass sheet 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, a glass ribbon is continuously formed from molten glass by the overflow downdraw method. The glass ribbon formed by the forming apparatus 400 is cut into a glass sheet having a predetermined size. The glass sheet is used as a glass substrate for flat panel displays such as liquid crystal displays and plasma displays.

(2) Configuration of Molding Device The detailed configuration of the molding device 400 will be described with reference to FIGS. The molding apparatus 400 includes the molded body 10, the partition plate 20, the cooling roller 30, the plurality of feed rollers 50, and the furnace wall 90. The furnace wall 90 is made of refractory bricks and accommodates the molded body 10, the partition plate 20, the cooling roller 30, and the feed roller 50. The space inside the furnace wall 90 is partitioned into a molded body accommodation zone 410 and a molded slow cooling zone 420 from the upper side to the lower side in the vertical direction. The molded body accommodation zone 410 and the molded slow cooling zone 420 are partitioned by the partition plate 20. Hereinafter, each component housed in the furnace wall 90 will be described.

(2-1) Molded Body The molded body 10 is a refractory material having a wedge-shaped cross section in the short-side direction. As shown in FIG. 3, the molded body 10 is disposed in the molded body accommodation zone 410 such that the wedge-shaped tip of the cross section points downward in the vertical direction. The molded body 10 continuously forms a glass ribbon G from molten glass by an overflow downdraw method.

  A detailed configuration of the molded body 10 will be described with reference to FIGS. The molded body 10 has an upper end surface 12, a pair of vertical side surfaces 14, a pair of inclined side surfaces 16, and an arc surface 18. The upper end surface 12 has a groove 12a formed in the longitudinal direction LD. One end of the groove 12 a is connected to the glass supply pipe 80. The upper end of the vertical side surface 14 is connected to both ends of the upper end surface 12 along the longitudinal direction LD. The upper end of the inclined side surface 16 is connected to the lower end of the vertical side surface 14 along the longitudinal direction LD. The pair of inclined side surfaces 16 are inclined so as to approach each other downward in the vertical direction. The upper end of the circular arc surface 18 is connected to the lower end of the inclined side surface 16 along the longitudinal direction LD. The arc surface 18 is an arc whose cross-sectional shape in the short direction SD is vertically downward.

  The molded body 10 has a shape in which the cross-sectional shape in the short direction SD differs depending on the point in the long direction LD. Specifically, as shown in FIG. 4, when the molded body 10 is viewed from a direction orthogonal to the longitudinal direction LD, the inclined side surface 16 is a pair that occupies a predetermined range from both ends of the longitudinal direction LD of the molded body 10. The upper end inclined side surface 16a1 and the pair of end lower inclined side surfaces 16a2 and the central inclined side surface 16b sandwiched between the pair of end upper inclined side surfaces 16a1. The lower end of the end upper inclined side surface 16a1 is connected to the upper end of the end lower inclined side surface 16a2. The arc surface 18 includes a pair of end arc surfaces 18a connected to the pair of lower end inclined side surfaces 16a2, and a center arc surface 18b smoothly connected to the center inclined side surface 16b.

  In FIG. 4, the cross section of the molded object 10 in line segment VV is shown by FIG. 5, and the cross section of the molded object 10 in line segment VI-VI is shown in FIG. FIG. 7 is an enlarged view of the lower part by overlapping the cross-sectional shapes of FIGS. 5 and 6. As shown in FIG. 7, the end upper inclined side surface 16a1 and the central inclined side surface 16b are inclined at the same angle. The lower end inclined side surface 16a2 is inclined at an angle closer to the horizontal than the upper end inclined side surface 16a1. The end arc surface 18a has the same cross-sectional shape as a part of the lower end portion of the cross-sectional shape of the central arc surface 18b. The molded body 10 according to the present embodiment is obtained by machining both ends of the longitudinal direction LD by machining from a molded body having the cross-sectional shape shown in FIG. 5 over the entire area in the longitudinal direction LD. Specifically, at both ends in the longitudinal direction LD of the molded body 10, the lower end slope having an inclination angle different from that of the central inclined side face 16 b which is an inclined face before being cut by cutting a part of the inclined face and the arc face. The side surface 16a2 is formed, and at the same time, the end arc surface 18a having a shorter length in the short direction SD and a lower height in the vertical direction than the central arc surface 18b, which is the arc surface before cutting, is formed.

(2-2) Partition plate The partition plate 20 is a heat insulating material arranged in the vicinity of the lower end of the molded body 10. The partition plate 20 is horizontally disposed on both sides of the glass ribbon G in the short direction SD. The partition plate 20 suppresses heat transfer between the molded body accommodation zone 410 and the molded slow cooling zone 420.

(2-3) Cooling roller The cooling roller 30 is a roller arranged in the vicinity of the partition plate 20 in the forming slow cooling zone 420. As shown in FIG. 2, the cooling roller 30 is positioned below the boundary line BL between the central inclined side surface 16 b and the end upper inclined side surface 16 a 1 in the vertical direction. The cooling rollers 30 are arranged on both sides of the glass ribbon G in the short direction SD on both sides of the glass ribbon G in the longitudinal direction LD. The cooling roller 30 cools the glass ribbon G molded in the molded body accommodation zone 410.

(2-4) Feed Roller The feed roller 50 is a roller disposed below the cooling roller 30 in the forming slow cooling zone 420. The feed rollers 50 are arranged on both sides of the glass ribbon G in the short direction SD on both sides of the glass ribbon G in the longitudinal direction LD. The feed roller 50a conveys the glass ribbon G conveyed by the cooling roller 30 downward.

(3) Operation (3-1) Glass Ribbon Forming Process The process of forming the glass ribbon G by the forming apparatus 400 will be described with reference to FIGS. The molten glass that has been generated in the dissolution tank 200 and from which bubbles have been removed in the clarification tank 300 is sent to the molding apparatus 400. In the molded product accommodation zone 410 of the molding device 400, the molten glass is supplied to the groove 12 a of the molded product 10 through the glass supply pipe 80. The molten glass stored in the groove 12 a overflows from the upper end surface 12 and diverts in the short direction SD of the molded body 10. A pair of the split molten glass flows down along the vertical side surface 14 and the inclined side surface 16. The pair of molten glass that has flowed down on both side surfaces of the molded body 10 is separated from the molded body 10 on the arc surface 18 and joins below the lower end of the molded body 10. The pair of molten glasses that have joined together are continuously formed into a glass ribbon G by being bonded together. The temperature of the glass ribbon G in the molded body accommodation zone 410 is about 1150 ° C.

  The glass ribbon G molded in the molded body accommodation zone 410 reaches the molding slow cooling zone 420. In the forming slow cooling zone 420, the central portion in the width direction of the glass ribbon G flows down without touching anything. On the other hand, both ends in the width direction of the glass ribbon G are selectively cooled to 800 to 900 ° C. by the cooling roller 30. Next, the glass ribbon G is conveyed vertically downward by the feed roller 50. The glass ribbon G is gradually cooled in the process of being conveyed by the feed roller 50, and then is taken out of the molding apparatus 400.

(3-2) Fusion process of molten glass In the molded object accommodation zone 410, the process in which a pair of molten glass joins away from the surface of the molded object 10 is demonstrated, referring FIG. The tangent line in the short direction SD of the arc surface 18 gradually approaches the horizontal direction as it proceeds downward in the vertical direction. Therefore, when the molten glass flows down along the circular arc surface 18, the vertical direction related to the molten glass necessary for forming the glass ribbon G at a required speed due to the interfacial tension F <b> 2 between the molten glass and the circular arc surface 18. When the continuous downward pulling force F1 is overcome, the molten glass is separated from the arc surface 18. Here, the pulling force F1 is a resultant force of the force acting on the molten glass by the feed roller 50 pulling both ends in the width direction of the glass ribbon G vertically downward and the gravity of the molten glass itself. Once the pair of molten glasses separated from the circular arc surface 18 is still kept below the viscosity required for fusion at the junction point CP located below the lower end of the molded body 10, it is fused and pasted again. Combined.

  The relationship between the interfacial tension F2 between the molten glass and the arc surface 18 and the tensile force F1 of the molten glass will be described in detail with reference to FIG. In order for the tensile force F1 of the molten glass to overcome the interfacial tension F2, the normal component F1n of the tensile force F1 needs to satisfy a condition (F1n> F2) greater than the interfacial tension F2. Here, “normal component F1n” means a component in a direction perpendicular to the arc tangent (broken line shown in FIG. 8) of the cross section of the arc surface 18 that passes through the force point AP of the tensile force F1. Hereinafter, as shown in FIG. 8, an angle θ formed by the tangent line and a perpendicular line (dashed line shown in FIG. 8) is referred to as an “inclination angle”. The interfacial tension F2 is a force acting in the direction opposite to the normal component F1n of the tensile force F1 from the point A of the tensile force F1. The normal component F1n of the tensile force F1 is calculated by multiplying the tensile force F1 and the sine of the inclination angle θ (sin θ). Since the cross-sectional shape of the arc surface 18 is a vertically downward arc, the tangent line becomes closer to the horizontal and the inclination angle θ increases as it goes downward. For this reason, the normal component F1n of the tensile force F1 concerning a molten glass becomes large, so that it goes below. Then, at a point where the normal component F1n of the tensile force F1 exceeds the interfacial tension F2, the molten glass is separated from the surface of the molded body 10. Therefore, the molten glass is easily separated from the surface of the molded body 10 as it approaches the lower end of the circular arc surface 18 of the molded body 10.

  In the present embodiment, the molten glass that has flowed down the boundary line BL between the central inclined side surface 16b and the end upper inclined side surface 16a1 of the molded body 10 is bonded to the surface of the molded body 10 after being separated from the glass ribbon G. It becomes the both ends of the width direction. Both ends in the width direction of the glass ribbon G flowing down the boundary line BL of the molded body 10 and coming into contact with the cooling roller 30 and the feeding roller 50 are cut later and are not used as products.

(4) Features (4-1)
In the molded body 10 in the present embodiment, both ends in the width direction of the glass ribbon G are selectively cooled by the cooling roller 30, and a low temperature rising airflow is generated from the cooling roller 30. And the molten glass which flows down the surface of the molded object 10 is cooled when the said updraft penetrate | invades into the molded object accommodation zone 410. FIG. Since the cooling roller 30 is positioned vertically below the boundary line BL between the central inclined side surface 16b and the end upper inclined side surface 16a1 of the molded body 10, the molten glass flowing down both ends in the longitudinal direction LD of the molded body 10 is It is cooled more strongly than the molten glass flowing down the center, and becomes a lower temperature. Therefore, the viscosity of the molten glass flowing down the both end portions in the longitudinal direction LD of the molded body 10 is higher than the viscosity of the molten glass flowing down the center portion. Therefore, the interfacial tension acting between the surface of both ends of the molded body 10 in the longitudinal direction LD and the molten glass is also small as the interfacial tension acting between the surface of the central portion and the molten glass.

  Here, it is assumed that the molded body 10 has the cross-sectional shape shown in FIG. 5 over the entire region in the longitudinal direction LD. In this case, the molten glass flowing down at both ends in the longitudinal direction LD of the molded body 10 has a lower interfacial tension than the molten glass flowing down at the central portion of the molded body 10 in the longitudinal direction LD. In the circular arc surface where the inclination angle becomes larger as it goes, it is separated further upward. The more the molten glass is separated above the surface of the molded body 10, the longer the interval from the time when the molten glass is separated from the molded body 10 to the time when the molten glass is merged at the merge point CP. While the molten glass is away from the molded body 10, the molten glass comes into contact with low-temperature air, so that the viscosity increases in a short time. If the viscosity of the molten glass increases too much, the molten glass does not fuse well at the joining point CP, and there is a possibility that cracks and the like occur in the formed glass ribbon G.

  In the present embodiment, in order to solve the above-described problem, the inclined surface and a part of the arc surface are scraped at both ends in the longitudinal direction LD of the molded body 10 to have an inclination angle different from that of the upper end inclined side surface 16a1. An end lower inclined side surface 16a2 is formed, and at the same time, an end arc surface 18a having a shorter length in the lateral direction SD and a lower height in the vertical direction than the central arc surface 18b is formed. FIG. 9 shows an enlarged view of a cross-sectional view of the molded body 10 shown in FIG. Hereinafter, the inclination angle of the lower end inclined side surface 16a2 is θ1, and the inclination angles of the upper end inclined side surface 16a1 and the central inclined side surface 16b are θ2. A connection point between the end lower inclined side surface 16a2 and the end arc surface 18a is BP1, a connection point between the central inclined side surface 16b and the center arc surface 18b is BP2, and a connection point between the upper end inclined side surface 16a1 and the end lower inclined side surface 16a2. Is BP3.

The inclination angle of the central portion of the molded body 10 in the longitudinal direction LD gradually increases from θ2 at the height position of the connection point BP2 to θ3 at the height position of the connection point BP1 as it proceeds downward.
The inclination angle of both ends of the longitudinal direction LD of the molded body 10 increases from θ2 to θ1 at the height position of the connection point BP3, and a constant value of θ1 from the height position of the connection point BP3 to the height position of the connection point BP1. And increases discontinuously from θ1 to θ3 at the height position of the connection point BP1. In the present embodiment, the inclination angle θ1 is larger than the inclination angle θ2, and the inclination angle θ3 is larger than the inclination angle θ1 (θ3>θ1> θ2).

  Here, it is assumed again that the molded body 10 has the cross-sectional shape shown in FIG. 5 over the entire region in the longitudinal direction LD. When the molten glass flowing down both ends in the longitudinal direction LD of the molded body 10 is separated from the surface of the molded body 10 at a point on the arc surface where the inclination angle is α (where θ2 <α <θ3). think of. In this case, an inclined surface having an inclination angle smaller than the inclination angle α is formed by cutting the inclined surface and the arc surface at both ends in the longitudinal direction LD of the molded body 10. In the present embodiment, the inclined surface having an inclination angle smaller than the inclination angle α corresponds to the lower end inclined side surface 16a2 having the inclination angle θ1. In the present embodiment, the molten glass flowing down both ends in the longitudinal direction LD of the molded body 10 has an end lower inclined side surface 16a2 having an inclination angle θ1 smaller than the inclination angle α required to leave the surface of the molded body 10. Since it flows down, it can flow down to the height position below the height position where the inclination angle becomes α in the central arc surface 18b without leaving the surface of the molded body 10.

  In the molded body 10 according to the present embodiment, as shown in FIG. 10, a center separation point DP2, which is a point at which the molten glass leaves the center arc surface 18b, is located on the center arc surface 18b. Further, as shown in FIG. 11, the end separation point DP1, which is the point at which the molten glass leaves the end arc surface 18a, is below the center separation point DP2, and is between the lower end inclined side surface 16a2 and the end arc surface 18a. Located near the connection point. That is, the distance from the end separation point DP1 to the lower end of the molded body 10 is shorter than the distance from the center separation point DP2 to the lower end of the molded body 10. In other words, the distance from the end separation point DP1 to the merge point CP is shorter than the distance from the center separation point DP2 to the merge point CP. Therefore, in the molded body 10 according to the present embodiment, the molten glass flowing down both ends of the longitudinal direction LD is more distant from the surface of the molded body 10 than the molten glass flowing down the central portion of the longitudinal direction LD. The interval until the time of merging at the merging point CP is short. Thereby, the molded object 10 which concerns on this embodiment can suppress that the viscosity of the molten glass which flowed down the both ends of longitudinal direction LD and left | separated from the surface of the molded object 10 raises.

  Therefore, the molded object 10 which concerns on this embodiment can suppress that the bonding in the both ends of the width direction of the glass ribbon G deteriorates. By using the molded body 10 according to the present embodiment, it is possible to manufacture a glass sheet that is less likely to have a defective shape at the end.

(4-2)
The molded body 10 according to the present embodiment can be obtained by machining a molded body having the cross-sectional shape shown in FIG. 5 over the entire area in the longitudinal direction LD. In the present embodiment, it is not necessary to provide a special device or mechanism inside and outside the molded body 10 in order to suppress a decrease in the temperature of the molten glass flowing down both ends in the longitudinal direction LD of the molded body 10. . Therefore, by using the molded body 10 according to the present embodiment, it is possible to reduce the cost for preventing the defective shape of the glass ribbon G.

(4-3)
In general, in the overflow downdraw method, it is desirable that the pair of molten glasses that have flowed down on both side surfaces of the molded body merge at the lower end of the molded body and be formed into a glass ribbon without leaving the molded body. For that purpose, it is the most desirable form that the molded body has a shape in which the lower end is completely pointed. However, the molded body is usually made of a refractory material having a low strength and a brittle material. Accordingly, a molded body having a completely sharpened lower end is not suitable for practical use because it has a high risk of partial loss in the life cycle from the start of processing to the end of operation through installation.

  The molded body 10 according to the present embodiment has an arc surface 18 at the lower end. Therefore, the molded body 10 according to the present embodiment is suitable for practical use as a manufacturing apparatus because it has a lower risk of partial loss compared to a molded body having a completely sharp lower end.

(5) Modification In the present embodiment, the end arc surface 18a of the molded body 10 has the same cross-sectional shape as a part of the lower end portion of the central arc surface 18b, but may have a different cross-sectional shape. For example, as shown in FIG. 12, the arc-shaped radius Ra of the cross section of the end arc surface 118a connected to the lower end inclined side surface 116a2 is the radius of the arc shape of the cross section of the central arc surface 118b connected to the central inclined side surface 116b. It may be smaller than Rb. The upper end of the lower end inclined side surface 116a2 is connected to the lower end of the upper end inclined side surface 116a1.

  In the molded body 10 according to the present embodiment, as shown in FIG. 7, the central arc surface 18b is smoothly connected to the central inclined side surface 16b, but the end arc surface 18a is discontinuously connected to the lower end inclined side surface 16a2. Therefore, when the molten glass that has reached the lower end of the lower end inclined side surface 16a2 does not flow down the end arc surface 18a, the molten glass leaves the molded body 10 at a discontinuous point between the lower end inclined side surface 16a2 and the end arc surface 18a. There is.

  In the molded body 110 in this modification, the end arc surface 118a is processed so that the end arc surface 118a is smoothly connected to the lower end inclined side surface 116a2. Thereby, the molten glass which flowed down the end lower inclined side surface 116a2 of the molded body 110 can flow down the end arc surface 118a. Also in this modification, by using the molded body 110, it is possible to manufacture a glass sheet that is less likely to have a defective shape at the end.

  The glass sheet manufacturing apparatus, the glass sheet manufacturing method, and the molded body according to the present invention can manufacture a glass sheet that has a low risk of partial defect of the molded body and is less likely to have a defective shape at the end.

DESCRIPTION OF SYMBOLS 10 Molding body 12 Upper end surface 12a Groove 14 Vertical side surface 16 Inclined side surface 16a1 2nd inclined surface (Upper end inclined side surface)
16a2 Third inclined surface (lower end inclined side surface)
16b 1st inclined surface (central inclined side surface)
18 Arc surface 18a Second arc surface (end arc surface)
18b First arc surface (central arc surface)
20 Partition plate 30 Cooling roller 50 Feeding roller 80 Glass supply pipe 90 Furnace wall 100 Glass sheet manufacturing apparatus 200 Dissolution tank 300 Clarification tank 400 Molding apparatus 410 Molded body accommodation zone 420 Molding slow cooling zone G Glass ribbon CP Merge point DP1 End separation point DP2 center separation point

JP 2009-518275 A

Claims (6)

A glass sheet manufacturing apparatus comprising a molded body for forming a glass sheet by fusing in the vicinity of the lower end after the molten glass is shunted and flowed down,
The molded body is
A first inclined surface that is a pair of inclined surfaces that are inclined so as to approach each other downward in the central portion in the longitudinal direction;
A pair of inclined surfaces that are inclined so as to approach each other downward at both ends in the longitudinal direction, and a second inclined surface that is inclined at the same angle as the first inclined surface;
A pair of inclined surfaces that are connected to the respective lower ends of the second inclined surfaces and inclined so as to approach each other downward at the both ends, as compared with the second inclined surface. A third inclined surface inclined at an angle close to horizontal,
A first arc surface connected to a lower end of the first inclined surface in the central portion and having a cross-sectional shape in a short direction that is a vertically downward arc;
A second arcuate surface that is connected to the lower end of the third inclined surface at the both end portions and whose cross-sectional shape is a vertically downward arc;
Have
The length in the short direction of the second arc surface is shorter than the length in the short direction of the first arc surface,
Glass sheet manufacturing equipment. A cooling roller that holds both ends in the width direction of the glass sheet formed by the molded body;
The cooling roller is disposed vertically below a boundary line between the central portion and the both end portions,
The glass sheet manufacturing apparatus according to claim 1. The radius of the arc of the cross section of the second arc surface in the short direction of the molded body is equal to or less than the radius of the arc of the cross section of the first arc surface in the short direction of the molded body.
The glass sheet manufacturing apparatus according to claim 1 or 2. The molded body is a refractory,
The glass sheet manufacturing apparatus of any one of Claim 1 to 3. A method for producing a glass sheet using a molded body for forming a glass sheet by merging and letting molten glass flow down and then joining,
The molded body is
A first inclined surface that is a pair of inclined surfaces that are inclined so as to approach each other downward in the central portion in the longitudinal direction;
A pair of inclined surfaces that are inclined so as to approach each other downward at both ends in the longitudinal direction, and a second inclined surface that is inclined at the same angle as the first inclined surface;
A pair of inclined surfaces that are connected to the respective lower ends of the second inclined surfaces and inclined so as to approach each other downward at the both ends, as compared with the second inclined surface. A third inclined surface inclined at an angle close to horizontal,
A first arc surface connected to a lower end of the first inclined surface in the central portion and having a cross-sectional shape in a short direction that is a vertically downward arc;
A second arcuate surface that is connected to the lower end of the third inclined surface at the both end portions and whose cross-sectional shape is a vertically downward arc;
Have
The length in the short direction of the second arc surface is shorter than the length in the short direction of the first arc surface,
Glass sheet manufacturing method. After the molten glass is diverted and flowed down, it is a molded body for forming a glass sheet by merging,
A first inclined surface that is a pair of inclined surfaces that are inclined so as to approach each other downward in the central portion in the longitudinal direction;
A pair of inclined surfaces that are inclined so as to approach each other downward at both ends in the longitudinal direction, and a second inclined surface that is inclined at the same angle as the first inclined surface;
A pair of inclined surfaces that are connected to the respective lower ends of the second inclined surfaces and inclined so as to approach each other downward at the both ends, as compared with the second inclined surface. A third inclined surface inclined at an angle close to horizontal,
A first arc surface connected to a lower end of the first inclined surface in the central portion and having a cross-sectional shape in a short direction that is a vertically downward arc;
A second arcuate surface that is connected to the lower end of the third inclined surface at the both end portions and whose cross-sectional shape is a vertically downward arc;
With
The length in the short direction of the second arc surface is shorter than the length in the short direction of the first arc surface,
Molded body.

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