Glass plate manufacturing device and glass plate manufacturing method

Abstract

A glass plate manufacturing device (1) having a structure in which a forming furnace (4) contains a forming body (2) used for forming molten glass (5) into a glass ribbon (6) by a down-draw method, and a supporting body (3) for supporting both ends of the forming body (2) in a width direction, is constructed as a main structure, wherein a heater (10) is provided on the supporting body (3).

Description

Technical Field

[0001] The present invention relates to an apparatus and a method for manufacturing a glass sheet by a down-draw method. Background Art

[0002] As is known, as a representative example of the down-draw method used in the field of glass sheet manufacturing, there is an overflow down-draw method in which a glass ribbon is continuously formed while molten glass flows down along both surfaces of a forming body having a substantially wedge-shaped cross section. As other down-draw methods, there are known slit down-draw methods, etc.

[0003] Patent Document 1 discloses an apparatus for producing a glass sheet by an overflow down-draw method. Both ends of a formed body in the width direction (longitudinal direction) as a component of the apparatus are supported by a support body.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: WO2012 / 132309 Summary of the invention

[0007] Problems to be solved by the invention

[0008] Generally, the periphery of a molded body is maintained at a high temperature by heating, etc. However, as disclosed in Patent Document 1, when both widthwise end portions of a molded body are supported by support bodies, the heat around the both widthwise end portions is taken away by the support bodies.

[0009] Therefore, the temperature of the portions of the formed body in contact with both ends of the glass ribbon in the width direction is lower than that of the portions of the formed body in contact with the central portion of the glass ribbon in the width direction. As a result, the thickness unevenness (degree of thickness unevenness) of the glass sheet as a product may increase, devitrification may occur, and it may be difficult to obtain a product of stable quality.

[0010] From the above viewpoints, an object of the present invention is to maintain the peripheral temperature of both ends in the width direction of a formed body at an appropriate temperature, thereby reducing the problems of uneven thickness and devitrification of a glass sheet.

[0011] Solutions to Solve Problems

[0012] The first aspect of the present invention completed to solve the above-mentioned problems is a glass plate manufacturing device, which contains a forming body used to form molten glass into a glass ribbon by a down-draw method, and a supporting body for supporting both ends of the width direction of the forming body in a forming furnace. The glass plate manufacturing device is characterized in that a heater is provided on the supporting body.

[0013] According to such a structure, since the support body supporting both ends of the formed body in the width direction is heated by the heater, the temperature drop around the both ends in the width direction in the forming furnace can be suppressed. Therefore, the temperature difference between the part of the formed body in contact with the central part of the formed glass ribbon in the width direction and the part of the formed body in contact with both ends in the width direction of the glass ribbon is reduced. As a result, the thickness unevenness (degree of thickness unevenness) of the glass sheet as a product is reduced, devitrification is less likely to occur, and a product of stable quality can be provided.

[0014] Based on this structure, preferably, the support body is a refractory brick.

[0015] In this way, the strength at high temperatures can be ensured and deformation of the support body can be prevented.

[0016] In the above configuration, the heater may be disposed in a hole formed in the support body.

[0017] In this way, only the heater can be replaced, and maintenance inspection, management, etc. can be easily performed.

[0018] In the above configuration, the heater may be disposed so as to straddle a hole formed in the support body and a hole formed in a furnace wall of the forming furnace.

[0019] In this way, the heater can be appropriately supported, and the heater can be easily installed and replaced.

[0020] In this configuration, the heater may be rod-shaped, the hole formed in the support body may be a through hole, the hole formed in the furnace wall of the forming furnace may be a through hole, and the heater may pass through these through holes.

[0021] In this way, the heater can be installed from outside the forming furnace and replaced during operation. In addition, the heater can be wired while being extended outside the forming furnace. Furthermore, by making the heater rod-shaped, the heater can be made slender. Thus, the through holes formed in the support body and the furnace wall can be made thin, and the heat dissipated from the forming furnace can be reduced.

[0022] In this configuration, an opening window for exposing the heater to an internal space of the forming furnace may be formed in the support body.

[0023] In this way, the heat from the heater is efficiently transferred to the inner space of the forming furnace through the opening window, so that the temperature of the atmosphere around the two ends in the width direction of the forming body can be increased. Therefore, the temperature difference between the portion of the forming body in contact with the central portion in the width direction of the glass ribbon and the portion of the forming body in contact with the two ends in the width direction of the glass ribbon is further reduced.

[0024] Based on this structure, the opening window may be arranged in the middle part of the central axis direction of the hole formed in the supporting body, and a sealant may be filled between the hole formed in the supporting body and the heater at both ends in the central axis direction of the hole formed in the supporting body.

[0025] When an opening window is provided, the atmosphere in the forming furnace easily flows out from between the hole of the support body and the heater through the opening window, and the temperature in the forming furnace is easily reduced. In this regard, if a sealing member is filled between the hole of the support body and the heater at both ends in the central axis direction of the hole of the support body, the outflow of the atmosphere in the forming furnace can be prevented, and the temperature in the forming furnace can be appropriately maintained.

[0026] In the structure in which the opening window is provided, a sealing material may be filled between the hole formed in the furnace wall of the forming furnace and the heater.

[0027] Also in such a case, the outflow of the atmosphere in the forming furnace can be prevented, and the temperature in the forming furnace can be appropriately maintained.

[0028] A second aspect of the present invention, which has been completed to solve the above-mentioned problems, is a method for manufacturing a glass sheet, which includes a forming step, in which a forming body and a support body for supporting both ends of the forming body in a width direction are accommodated in a forming furnace, and molten glass is formed into a glass ribbon using a down-draw method and the forming body. The glass sheet manufacturing method is characterized in that, in the forming step, the support body is heated by a heater provided on the support body.

[0029] When this method is adopted, similarly to the matters described above, problems such as uneven thickness (degree of uneven thickness) and devitrification of the glass plate to be a product are unlikely to occur, and products of stable quality can be provided.

[0030] Effects of the Invention

[0031] According to the present invention, the peripheral temperature of both end portions in the width direction of the formed body can be maintained at an appropriate temperature, thereby reducing the problems of uneven thickness and devitrification of the glass sheet. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1It is a longitudinal sectional side view which shows the main part of the glass plate manufacturing apparatus which concerns on embodiment of this invention.

[0033] Figure 2 It is along Figure 1 The longitudinal section main view obtained by cutting along the AA line.

[0034] Figure 3 It is along Figure 2 The longitudinal sectional side view is obtained by cutting along the BB line.

[0035] Figure 4 It is along Figure 1 The longitudinal section main view obtained by cutting along the CC line.

[0036] Figure 5 Yes Figure 1 A longitudinal sectional side view obtained by enlarging one side portion of the main part.

[0037] Figure 6 Yes Figure 2 A longitudinal sectional front view obtained by enlarging one side portion of the main part.

[0038] Figure 7 Yes Figure 3 A longitudinal sectional side view obtained by enlarging one side portion of the main part.

[0039] Figure 8 Yes Figure 4 A longitudinal sectional front view obtained by enlarging one side portion of the main part. DETAILED DESCRIPTION

[0040] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0041] [Glass sheet manufacturing device]

[0042] Figure 1 1 is a longitudinal sectional side view showing a main part of a glass plate manufacturing apparatus according to an embodiment of the present invention. Figure 2 It is along Figure 1 The longitudinal section view is obtained by cutting along the AA line. Figure 3 It is along Figure 2 The longitudinal section side view obtained by cutting along the BB line, Figure 4 It is along Figure 1The longitudinal sectional front view is obtained by cutting along the CC line of the glass sheet. As shown in the above figures, the glass sheet manufacturing device 1 includes a forming body 2, a pair of supporting bodies 3, and a forming furnace 4 for accommodating the forming body 2 and the supporting bodies 3 as main components. The forming body 2 forms the molten glass 5 into a glass ribbon 6 by the overflow down-draw method in the middle part in the width direction. The pair of supporting bodies 3 is provided to support the two ends of the forming body 2 in the width direction. Here, the "width direction" is Figure 2 as well as Figure 4 The left-right direction in FIG. 2 represents the long side direction of the molded body 2 in the present embodiment.

[0043] The molded body 2 has an overflow trough 7 formed at the top, and a pair of surfaces 8 for the molten glass 5 overflowing from the overflow trough 7 to flow down. The pair of surfaces 8 are respectively composed of an upper vertical surface 8a and a lower inclined surface 8b (see Figure 1 as well as Figure 4 A pair of vertical surface portions 8a are formed on the upper rectangular parallelepiped portion 2a of the molded body 2. A pair of inclined surface portions 8b are formed on the tapered portion 2b which gradually becomes thinner toward the bottom of the molded body 2 (see Figure 1 ). After the molten glass flowing down the pair of vertical surfaces 8a and the pair of inclined surfaces 8b is integrated at the lower end 2c of the forming body 2, it is conveyed downward via a cooling roller or the like outside the figure, thereby continuously forming a glass ribbon 6. The forming body 2 is composed of refractory bricks such as dense zircon, alumina, and zirconia.

[0044] The support body 3 is a rectangular parallelepiped refractory brick. The two ends of the molded body 2 in the width direction respectively have a rectangular parallelepiped protrusion 2d and an end surface 2e on the width direction outer side of the tapered portion 2b (see Figure 2 as well as Figure 4 ). The protrusions 2d are respectively provided to protrude outward in the width direction from the upper part of the molded body 2. In addition, the protrusions 2d are respectively placed on the upper surface of the support body 3. Thus, the weight of the molded body 2 is borne by a pair of support bodies 3. In the present embodiment, the lower end of the protrusion 2d of the molded body 2 is lower than the upper end of the tapered portion 2b (inclined surface 8b). In other words, the upper end of the support body 3 is lower than the upper end of the inclined surface 8b of the molded body 2. Furthermore, the end surface 3a on the inner side in the width direction of the support body 3 is in contact with the end surface 2e on the outer side in the width direction of the tapered portion 2b of the molded body 2 (refer to Figure 2 as well as Figure 4 The support body 3 is composed of refractory bricks such as dense zircon, aluminum zircon, and alumina-rich mullite.

[0045] The furnace wall of the forming furnace 4 includes: an end wall portion 4a, which covers the outer side of the protruding portion 2d of the forming body 2 in the width direction; a side wall portion 4b, which covers the outer side of the two surfaces 8 of the forming body 2 in the front-back direction; a top wall portion 4c, which covers the upper side of the forming body 2; and a bottom wall portion 4d, which covers the lower side of the forming body 2. Here, the "front-back direction" is Figure 1 as well as Figure 3 The left-right direction in the figure and the thickness direction of the molded body 2 are indicated. A slit-shaped opening 4e is formed in the center of the bottom wall 4d and is long in the width direction. The opening 4e is used to allow the molten glass 5 integrated at the lower end 2c of the molded body 2 to pass through (see Figure 1 as well as Figure 2 ).

[0046] Base bodies 9 are placed at four corners of the bottom wall 4d of the forming furnace 4. A pair of supports 3 are placed on the pair of base bodies 9. The furnace walls 4a to 4d of the forming furnace 4 are composed of a plurality of refractory bricks. The base body 9 is also composed of refractory bricks.

[0047] The end surface portion 3b of the support body 3 on the outer side in the width direction is separated from the end wall portion 4a of the forming furnace 4 (see Figure 2 as well as Figure 4 ). On the other hand, the side surface portion 3c of the support body 3 on the outer side in the front-rear direction is in contact with or close to the side wall portion 4b of the forming furnace 4 (refer to Figure 1 as well as Figure 3 ).

[0048] A plurality of heaters 10 are provided on each of the pair of support bodies 3. In the example shown in the figure, heaters 10 are provided on the upper layer and the lower layer of each support body 3 (see Figure 2 as well as Figure 4 ). Each heater 10 is in the shape of a rod with a circular cross section, and these heaters 10 are inserted into through holes 11 formed in each support body 3. These through holes 11 are formed separately at upper and lower parts of each support body 3 in a manner extending in the front-to-back direction. In detail, the through holes 11 formed at upper and lower parts of the center part in the front-to-back direction of each support body 3, and the through holes 11 formed separately at upper and lower parts of the two ends in the front-to-back direction are arranged on the same axis (refer to Figure 3 ). In addition, through holes 12 communicating with the through holes 11 (through holes 11 at both ends in the front-rear direction) of the support body 3 are also formed in the side wall portion 4b of the forming furnace 4. Each heater 10 penetrates in a manner spanning the through hole 11 of the support body 3 and the through hole 12 of the side wall portion 4b, and extends outward from the side wall portion 4b.

[0049] Although not shown, heaters mainly for heating the molten glass 5 flowing down on both surfaces 8 of the forming body 2 are disposed on the side wall portion 4 b of the forming furnace 4 so as not to interfere with the support body 3 .

[0050] Figure 5 Yes Figure 1 A longitudinal sectional side view obtained by enlarging one side portion of the main part of Figure 6 Yes Figure 2 A longitudinal sectional front view obtained by enlarging one side portion of the main part. Figure 7 Yes Figure 3 A longitudinal sectional side view obtained by enlarging one side portion of the main part of Figure 8 Yes Figure 4 As shown in the above figures, the support body 3 is provided with an opening window 13 for exposing the two heaters 10 in the internal space 4x of the forming furnace 4.

[0051] These opening windows 13 are formed in the middle part of the through hole 11 in the direction of the central axis (two places on both sides of the center in the direction of the central axis). Specifically, concave opening windows 13 are formed between the through hole 11 in the central part in the front-to-back direction and the through holes 11 at the two ends in the front-to-back direction, and each through hole 11 is connected to these opening windows 13. Moreover, these opening windows 13 are shaped so that the length in the front-to-back direction gradually increases as they move from the top to the bottom, and are formed so as not to overlap with the molded body 2 (the tapered part 2b) (refer to Figure 5 ). In addition, the inner edges of the opening windows 13 in the front-back direction are inclined in a manner similar to the inclined surface 8b of the molded body 2, and the outer edges of the opening windows 13 in the front-back direction are formed in a manner along the vertical direction.

[0052] The seal 14 is filled between the through hole 11 formed at both ends of the support body 3 in the front-back direction and the heater 10. In other words, the seal 14 is filled over the entire circumference of the heater 10 at both ends of the through hole 11 formed at two locations of the support body 3 in the central axis direction. The seal 15 is also filled over the entire circumference of the heater 10 between the through hole 12 formed in the side wall portion 4b of the forming furnace 4 and the heater 10. These seals 14 and 15 are heat insulating materials, for example, composed of refractory fibers.

[0053] It should be noted that based on Figures 5 to 8 The above description is made only on one side of the main part of the glass plate manufacturing apparatus 1 , but the same description is also applicable to the other side of the main part.

[0054] According to the glass plate manufacturing apparatus 1 having the above-described structure, the following effects are achieved.

[0055] Since the support body 3 supporting both ends of the forming body 2 in the width direction is heated by the heater 10, the temperature drop around the both ends in the width direction (particularly the end surface 2e on the width direction outer side of the tapered portion 2b) in the internal space 4x of the forming furnace 4 can be suppressed. Therefore, the temperature difference between the portion of the forming body 2 in contact with the central portion in the width direction of the glass ribbon 6 and the portion of the forming body 2 in contact with both ends in the width direction of the glass ribbon 6 is reduced. As a result, the thickness unevenness (degree of thickness unevenness) of the glass sheet to be a product is reduced, and devitrification is less likely to occur, so that a product of stable quality can be provided. It should be noted that, as described above, a heater not shown is provided on the side wall portion 4b of the forming furnace 4, but the heater cannot fully suppress the temperature drop caused by the heat taken away by the support body 3.

[0056] In addition, since the heater 10 is inserted through the through hole 11 formed in the support body 3, only the heater 10 can be replaced, and maintenance inspection, management, etc. can be easily performed. In addition, since the heater 10 is also inserted through the through hole 12 formed in the side wall portion 4b of the forming furnace 4, the heater 10 can be replaced from the outside of the forming furnace 4, and maintenance inspection, management, etc. can be further easily performed.

[0057] Furthermore, by forming opening windows 13 in the support body 3 for exposing the heater 10 in the internal space 4x of the forming furnace 4, the heat from the heater 10 is efficiently transferred to the internal space 4x of the forming furnace 4 through the opening windows 13. Thus, the temperature drop around the both ends in the width direction of the formed body 2 (particularly the end surface 2e on the outer side in the width direction of the tapered portion 2b) can be further suppressed. Figure 5 As shown, the opening window 13 is not overlapped with the formed body 2 and has a shape whose length in the front-rear direction gradually increases from the upper side to the lower side, so that the heat from the heater 10 can be transferred to the internal space 4x of the forming furnace 4 as much as possible.

[0058] In addition, when the opening window 13 is provided, the atmosphere in the forming furnace 4 is likely to flow out from between the through holes 11 and 2 and the heater 10 through the opening window 13, and the temperature in the forming furnace 4 is likely to decrease accordingly. In view of this, in the glass sheet manufacturing apparatus 1 of the present embodiment, the sealant 14 is filled between the through hole 11 and the heater 10 at both ends in the central axis direction of the through hole 11 formed in the support body 3. In addition, the sealant 15 is also filled between the through hole 12 formed in the side wall portion 4b of the forming furnace 4 and the heater 10. Thus, the outflow of the atmosphere in the forming furnace 4 can be prevented, and the temperature in the forming furnace 4 can be appropriately maintained.

[0059] In addition, the glass plate manufacturing apparatus 1 of this invention is not limited to the said embodiment, Various deformation|transformation as shown below is possible.

[0060] That is, in the above-mentioned embodiment, the through hole 11 is formed in the support body 3, but a non-through hole may be formed in the support body 3. In addition, the heater 10 is made into a rod shape, but the heater 10 may be a heater in a shape other than a rod shape. Moreover, the heater 10 may be buried in the support body 3. In addition, for one support body 3, the number of heaters 10 is not limited to two, and may be one or more than three, or the heaters 10 may be arranged in multiple layers and multiple rows. Moreover, in the above-mentioned embodiment, one opening window 13 is configured to expose all the heaters 10 in the upper and lower layers, but a plurality of opening windows 13 may be formed in the upper and lower parts, and these opening windows 13 expose the heaters 10 in the upper and lower layers one by one. In addition, the through hole 12 is formed in the side wall portion 4b of the forming furnace 4, but a non-through hole may be formed in the side wall portion 4b, or no hole may be formed in the side wall portion 4b. Moreover, the support body 3 is separated from the end wall portion 4a of the forming furnace 4, but the support body 3 may be in contact with or close to the end wall portion 4a. In this case, a hole extending in the width direction may be formed in the support body 3 , a hole may also be formed in the end wall portion 4 a , and the heater 10 may pass through these holes in a straddling manner.

[0061] In the above embodiment, the upper end of the support body 3 is lower than the upper end of the inclined surface 8b of the molded body 2, but the upper end of the support body 3 may be flush with or higher than the upper end of the inclined surface 8b.

[0062] Moreover, in the above-mentioned embodiment, the present invention is applied to the case where the molten glass 5 is formed into the glass ribbon 6 by the overflow down-draw method, but the present invention can also be applied to the forming body used for forming the molten glass into the glass ribbon by the slit down-draw method and the supporting body for supporting the two ends of the width direction of the forming body.

[0063] [Glass plate manufacturing method]

[0064] Next, a method for producing a glass plate according to another embodiment of the present invention will be described. Figures 1 to 8The glass sheet manufacturing method includes a forming step, in which a forming body 2 and a support body 3 supporting both ends of the forming body 2 in the width direction are accommodated in a forming furnace 4, and a molten glass 5 is formed into a glass ribbon 6 by a down-draw method using the forming body 2. In addition, in the forming step, the support body 3 is heated by a heater 10 provided on the support body 3. Therefore, when using the glass sheet manufacturing method, the problem of uneven thickness (degree of uneven thickness) and devitrification of the glass sheet to be a product is unlikely to occur for the same reasons as those described in the above-mentioned glass sheet manufacturing device 1, and a product of stable quality can be provided.

[0065] Description of reference numerals:

[0066] 1 Glass sheet manufacturing device

[0067] 2 formed body

[0068] 3 Support body

[0069] 4 Forming furnace

[0070] 4a Furnace wall (end wall)

[0071] 4b Furnace wall (side wall)

[0072] 4x Inner space of the forming furnace

[0073] 5 Molten Glass

[0074] 6 Glass ribbon

[0075] 10. Heater

[0076] 11 Through hole formed in the support

[0077] 12 Through holes formed in the furnace wall

[0078] 13 Opening Window

[0079] 14 Sealing element of the support body

[0080] 15 Furnace wall seals.

Claims

1. A glass sheet manufacturing device, wherein a forming body used for forming molten glass into a glass ribbon by a down-draw method and a support body for supporting both ends of the forming body in a width direction are accommodated in a forming furnace, The glass sheet manufacturing device is characterized in that: The width direction is the long side direction of the molded body, The molded body includes protrusions that are respectively provided to protrude from an upper portion of the molded body toward the outer side in the width direction. Each of the protrusions is placed on the upper surface of the support body, The support body is provided with a heater.

2. The glass sheet manufacturing device according to claim 1, wherein: The supporting body is a refractory brick.

3. The glass sheet manufacturing device according to claim 1 or 2, wherein: The heater is disposed in a hole formed in the support body.

4. The glass sheet manufacturing device according to claim 3, wherein: The heater is disposed across a hole formed in the support body and a hole formed in a furnace wall of the forming furnace.

5. The glass sheet manufacturing apparatus according to claim 4, wherein: The heater is in a rod shape, the hole formed in the support body is a through hole, and the hole formed in the furnace wall of the forming furnace is a through hole, and the heater passes through these through holes.

6. The glass sheet manufacturing apparatus according to claim 4 or 5, wherein: The support body is formed with an opening window for exposing the heater to the inner space of the forming furnace.

7. The glass sheet manufacturing apparatus according to claim 6, wherein: The opening window is provided in the middle part of the central axis direction of the hole formed in the support body, At both ends of the hole formed in the support body in the central axis direction, a sealing material is filled between the hole formed in the support body and the heater.

8. The glass sheet manufacturing apparatus according to claim 6, wherein: A sealing member is filled between the hole formed in the furnace wall of the forming furnace and the heater.

9. A method for manufacturing a glass sheet, comprising a forming step, wherein a forming body and a support body for supporting protrusions formed at both ends of the forming body in a width direction are accommodated in a forming furnace, and molten glass is formed into a glass ribbon by a down-draw method using the forming body, The glass plate manufacturing method is characterized in that: The width direction is the long side direction of the molded body, The molded body includes protrusions that are respectively provided to protrude from an upper portion of the molded body toward the outer side in the width direction. Each of the protrusions is placed on the upper surface of the support body, In the forming step, the support body is heated by a heater provided on the support body.

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