Glass transfer apparatus and method for manufacturing glass articles

Abstract

To reduce oxidation and vaporization of a flange part provided on an agitation vessel.SOLUTION: A glass transfer device comprises an agitation vessel 3 which agitates molten glass GM, and a refractory material 10 which holds the agitation vessel 3. The agitation vessel 3 comprises a cylindrical main body part 7 and a lower flange part 12 provided at a lower part of the main body part 7. The refractory material 10 covers an outer peripheral surface 7a of the main body part 7, an upper surface 12a of the lower flange part 12, an undersurface 12b of the lower flange part 12, and an outer peripheral surface 12c of the lower flange part 12.SELECTED DRAWING: Figure 2

Description

【Technical Field】 【0001】 The present invention relates to an apparatus for transferring molten glass while stirring it and a method for manufacturing a glass article using the apparatus. 【Background Art】 【0002】 As is well known, when manufacturing glass articles such as glass plates and glass tubes, the molten glass flowing out from a melting furnace is transferred by a transfer device. In this transfer device, a cylindrical stirring tank having a bottom wall portion at the lower end may be disposed. 【0003】 For example, the glass plate manufacturing apparatus disclosed in Patent Document 1 includes a stirring tank in the middle of a glass transfer device that transfers molten glass. The stirring tank includes a noble metal tube that allows molten glass to flow through its internal space. The noble metal tube is made of, for example, platinum or a platinum alloy and is arranged along the vertical direction. The periphery of this noble metal tube is covered with a refractory (see paragraph 0031 and FIG. 2 of the same document). 【0004】 The noble metal tube includes electrodes for heating the molten glass flowing through its interior. The electrodes are provided at the upper and lower ends of the noble metal tube. Further, the electrodes include a flange portion (a flange-like portion) having a diameter larger than the outer diameter of the noble metal tube (see paragraph 0034 and FIG. 2 of the same document). 【Prior Art Documents】 【Patent Documents】 【0005】 【Patent Document 1】 Japanese Unexamined Patent Application Publication No. 2012 - 101970 【Summary of the Invention】 【Problems to be Solved by the Invention】 【0006】 In the conventional stirring tank described above, a portion of the flange portion of the electrode of the precious metal tube is exposed and not covered by refractory material (see Figure 2 in the same document). In this state, if the flange portion is made of platinum or a platinum alloy, there is a risk that the exposed portion of the flange portion may oxidize and volatilize while the precious metal tube is transporting molten glass. 【0007】 This invention has been made in view of the above circumstances, and its technical objective is to reduce oxidation and volatilization of the flange portion provided in the stirring tank. [Means for solving the problem] 【0008】 (1) The present invention is for solving the above problems and provides a glass transfer device comprising a stirring tank for stirring molten glass and a refractory material for holding the stirring tank, wherein the stirring tank comprises a cylindrical main body and a lower flange portion provided at the lower part of the main body, and the refractory material covers the outer circumferential surface of the main body, the upper surface of the lower flange portion, the lower surface of the lower flange portion, and the outer circumferential surface of the lower flange portion. 【0009】 With this configuration, the outer surface of the main body of the stirring tank, and the upper, lower, and outer surfaces of the lower flange are covered with refractory material, thereby reducing the exposure of the main body and the lower flange to air. This effectively reduces oxidation and volatilization of the lower flange. 【0010】 (2) In the configuration described in (1) above, the stirring tank may be provided with an upper flange portion located on the upper part of the main body, and the refractory material may cover the lower surface of the upper flange portion and the outer peripheral surface of the upper flange portion. This makes it possible to reduce oxidation and volatilization of the upper flange portion. 【0011】 (3) In the configuration described in (2) above, the main body may have an opening that opens upward, and the glass transfer device may be provided with a cover member that covers the upper surface of the upper flange and the opening of the main body. 【0012】 With this configuration, by covering the upper surface of the upper flange portion in the stirring tank with a lid member, the exposure of the upper surface of the upper flange portion is reduced, and oxidation and volatilization of this upper surface can be reduced. 【0013】 (4) In any of the configurations described in (1) to (3) above, the refractory material may include an amorphous refractory layer covering the upper surface of the lower flange portion, the lower surface of the lower flange portion, and the outer peripheral surface of the lower flange portion. 【0014】 With this configuration, the upper surface, lower surface, and outer peripheral surface of the lower flange can be suitably covered with an amorphous refractory layer. 【0015】 (5) In the configuration described in (4) above, the refractory material may include a refractory brick layer disposed on the outside of the amorphous refractory material layer. 【0016】 With this configuration, by covering the stirring tank with an amorphous refractory layer and a refractory brick layer, the flange portion of the stirring tank is reliably covered, and the stirring tank can be held securely in place. 【0017】 (6) In the configuration described in any of (1) to (5) above, the lower flange portion may be provided with a cooling mechanism for cooling the lower flange portion. 【0018】 This configuration makes it possible to more effectively reduce oxidation and volatilization of the lower flange portion. 【0019】 (7) In the configuration described in any of (1) to (6) above, the upper flange portion may be provided with a cooling mechanism for cooling the upper flange portion. 【0020】 This configuration makes it possible to more effectively reduce oxidation and volatilization of the upper flange portion. 【0021】 (8) The manufacturing method of the glass article according to the present invention is for solving the above problems, and is characterized by including a transfer step of transferring molten glass using the glass transfer device described in any one of (1) to (7) above. 【0022】 According to such a configuration, the same effects as those of the above-described glass transfer device can be obtained. 【Effects of the Invention】 【0023】 According to the present invention, oxidation and volatilization of the flange portion provided in the stirring tank can be reduced. 【Brief Description of the Drawings】 【0024】 [Figure 1] It is a side view showing a manufacturing apparatus of a glass article. [Figure 2] It is a cross-sectional view of a stirring tank. [Figure 3] It is a perspective view of a main body portion related to a stirring tank. [Figure 4] It is a cross-sectional view taken along the line IV-IV of FIG. 2. [Figure 5] It is a cross-sectional view showing another example of a stirring tank. [Figure 6] It is a perspective view of a main body portion related to a stirring tank. [Figure 7] It is a cross-sectional view taken along the line VII-VII of FIG. 5. 【Modes for Carrying Out the Invention】 【0025】 Hereinafter, modes for carrying out the present invention will be described with reference to the drawings. 【0026】 Figure 1 shows an apparatus for manufacturing glass plates as glass articles. This manufacturing apparatus comprises, in order from upstream, a melting tank 1, a clarification tank 2, a stirring tank (stirring pot) 3, a pot 4, a molded body 5, and glass supply passages 6a to 6d connecting these components 1 to 5. In addition, the manufacturing apparatus includes an annealing furnace (not shown) for slowly cooling the glass ribbon GR formed by the molded body 5, and a cutting device (not shown) for cutting the glass ribbon GR after annealing. The clarification tank 2, the stirring tank (stirring pot) 3, the pot 4, and the glass supply passages 6a to 6d function as a glass transfer device (feeder) for transporting molten glass GM. 【0027】 The dissolution tank 1 is a container for performing a dissolution process in which the glass raw materials introduced are dissolved to obtain molten glass GM. The dissolution tank 1 is connected to the clarification tank 2 by a glass supply passage 6a. 【0028】 The clarification tank 2 is a container for performing a clarification process in which molten glass GM is transferred while being degassed by the action of a clarifying agent. The clarification tank 2 is connected to the stirring tank 3 by a glass supply passage 6b. 【0029】 The stirring tank 3 is a tubular container with a bottom used for the process of homogenizing the clarified molten glass GM while transferring it. The stirring tank 3 is connected to the pot 4 by a glass supply passage 6c. 【0030】 As shown in Figure 2, the stirring tank 3 comprises a main body 7 through which molten glass GM flows, a stirrer 8 for stirring the molten glass GM in the main body 7, and a lid member 9 positioned on top of the main body 7. The stirring tank 3 is also held in place by a refractory material 10. 【0031】 The main body 7 is arranged in a vertical orientation along the vertical direction. The main body 7 is constructed in a cylindrical shape from, for example, platinum or a platinum alloy. In this invention, platinum includes reinforced platinum, and platinum alloy includes reinforced platinum alloy. 【0032】 As shown in Figures 2 and 3, the main body 7 has an upper flange portion 11 provided on the outer circumference of the upper end of the main body 7 and a lower flange portion 12 provided on the outer circumference of the lower end of the main body 7. The main body 7 also has an opening 13a that opens upward at its upper end and a bottom wall portion 13b at its lower end. 【0033】 The main body 7 has a supply port 14 at its upper part for supplying molten glass GM into the main body 7, and a discharge port 15 at its lower part for discharging molten glass GM. The supply port 14 of the main body 7 is connected to a glass supply passage 6b provided between the clarification tank 2 and the stirring tank 3. The discharge port 15 of the main body 7 is connected to a glass supply passage 6c provided between the stirring tank 3 and the pot 4. 【0034】 As shown in Figures 3 and 4, each flange portion 11, 12 is configured in a disc shape and is formed to surround the entire circumference of the main body portion 7. Each flange portion 11, 12 is integrally constructed (welded) with the main body portion 7 so as to be concentric with the main body portion 7. Each flange portion 11, 12 has an upper surface 11a, 12a, a lower surface 11b, 12b, and an outer peripheral surface 11c, 12c. Each flange portion 11, 12 is made of, for example, platinum or a platinum alloy. A part of each flange portion 11, 12 may be made of another metal such as nickel or a nickel alloy. 【0035】 Each flange portion 11, 12 is equipped with an electrode portion 16 that transmits electricity together with each flange portion 11, 12, and a cooling mechanism 17 that cools each flange portion 11, 12 and the electrode portion 16. 【0036】 The electrode portion 16 is made of a plate-like material such as platinum, platinum alloy, nickel, or copper. The electrode portion 16 has a predetermined width and is an elongated portion that protrudes radially outward from the outer circumference of the flange portions 11 and 12. A power supply (not shown) is connected to the electrode portion 16. 【0037】 The cooling mechanism 17 includes cooling pipes 18 arranged on the upper surfaces 11a and 12a of each flange portion 11 and 12. The cooling pipes 18 are made of, for example, copper, but are not limited to this material. A refrigerant, such as a gas or liquid, is circulated and supplied through the cooling pipes 18. 【0038】 The cooling piping 18 includes a flange cooling section 19 for cooling the flange portions 11 and 12, and an electrode cooling section 20 for cooling the electrode portion 16. The flange cooling section 19 is configured in a circular or arc shape to correspond to the circular shape of the flange portions 11 and 12. The electrode cooling section 20 is configured in a straight line along the longitudinal direction of the electrode portion 16. 【0039】 The stirrer 8 has a shaft 21 and a plurality of stirring blades 22 mounted along the longitudinal direction of the shaft 21. The stirrer 8 stirs the molten glass GM in the stirring tank 3 by rotating the plurality of stirring blades 22 around the shaft 21 as the shaft 21 rotates. A motor (not shown) is connected to the upper end of the shaft 21 as a drive device, and the shaft 21 rotates in a predetermined direction as the motor is driven. 【0040】 As shown in Figure 2, the lid member 9 is installed at the upper end of the main body 7 so as to close the opening 13a of the main body 7. The lid member 9 covers the upper surface 11a of the upper flange portion 11. The lid member 9 is constructed by covering the surface (at least the bottom surface and outer peripheral surface) of a plate-shaped refractory material with a plate member or film member made of platinum or a platinum alloy. The lid member 9 has a hole 9a through which the shaft 21 of the stirrer 8 is inserted. 【0041】 As shown in Figure 2, the refractory material 10 comprises an amorphous refractory layer 10a that is in contact with the stirring tank 3, and a refractory brick layer 10b that is positioned outside the amorphous refractory layer 10a. 【0042】 The monolithic refractory layer 10a is formed by filling the space between the stirring tank 3 and the refractory brick layer 10b with monolithic refractory material. The monolithic refractory layer 10a covers the outer circumferential surface 7a of the main body 7, the lower surface 11b and outer circumferential surface 11c of the upper flange portion 11, and the upper surface 12a, lower surface 12b and outer circumferential surface 12c of the lower flange portion 12. In addition, the monolithic refractory layer 10a covers a part of the electrode portion 16. Examples of monolithic refractory materials used in the monolithic refractory layer 10a include castable refractory material (e.g., alumina castable), plastic refractory material, and refractory mortar. 【0043】 The refractory brick layer 10b is constructed by arranging multiple refractory bricks to cover the periphery of the amorphous refractory layer 10a. Examples of refractory bricks used in the refractory brick layer 10b include fired bricks such as silica bricks, clayey refractory bricks, high-alumina bricks, silicon carbide refractory bricks, chromium bricks, magnesia bricks, dolomite bricks, sillimanite bricks, cyanide compound alumina bricks, mullite bricks, zirconite bricks, mullite bricks, and alundum bricks, as well as non-fired bricks such as graphite bricks, silicon carbide graphite bricks, and high-alumina bricks. 【0044】 Pot 4 is a container for performing a conditioning process to adjust the molten glass GM to a state suitable for molding while transferring it. Pot 4 is exemplified as a volume section for adjusting the viscosity and flow rate of the molten glass GM. Pot 4 is connected to the molded body 5 by a glass supply passage 6d. 【0045】 The molded body 5 is formed from molten glass GM into a plate shape by the overflow downdraw method. Specifically, the molded body 5 has a roughly wedge-shaped cross-section (the cross-sectional shape perpendicular to the plane of the paper in Figure 1), and an overflow groove (not shown) is formed on the upper part of the molded body 5. 【0046】 The molded body 5 allows the molten glass GM to overflow from the overflow groove and flow down along the side walls on both sides of the molded body 5 (the sides located on the front and back sides of the paper surface). The molded body 5 fuses the flowing molten glass GM at the lower top of the side walls. This forms a strip-shaped glass ribbon GR. After passing through an annealing furnace, the strip-shaped glass ribbon GR is cut by a cutting device to obtain glass plates of the desired dimensions. 【0047】 The glass plates obtained in this way, for example, have a thickness of 0.01 to 1 mm and can be used as substrates or protective covers for displays such as liquid crystal displays and organic EL displays, organic EL lighting, and solar cells. 【0048】 In addition to the above configuration, the molded body 5 may also employ other down-draw methods such as the slot down-draw method, or a molding apparatus utilizing the float method may be provided instead of the molded body 5. 【0049】 As for the composition of the glass, for example, alkali aluminosilicate glass or alkali-free glass can be used. Here, alkali-free glass is glass that does not substantially contain alkali components (alkali metal oxides), and specifically, it is glass in which the weight ratio of alkali components is 3000 ppm or less. The weight ratio of alkali components is preferably 1000 ppm or less, more preferably 500 ppm or less, and most preferably 300 ppm or less. Alkali aluminosilicate glass is suitable as glass for chemical strengthening. 【0050】 The glass supply passages 6a to 6d function as glass transfer devices for transporting molten glass GM. Each glass supply passage 6a to 6d includes a glass transfer pipe equipped with a heating device and a cooling device. Each glass supply passage 6a to 6d is composed of a single glass transfer pipe or by connecting multiple glass transfer pipes. The entire glass transfer pipe is covered with an insulating material such as brick (not shown). 【0051】 The following describes a method for manufacturing glass plates using the manufacturing apparatus with the above configuration. In this method, raw glass is melted in a melting tank 1 (melting step) to obtain molten glass GM. Then, the molten glass GM is subjected to a clarification step in a clarification tank 2, a homogenization step in a stirring tank 3, and a conditioning step in a pot 4, in that order. After that, the molten glass GM is transferred to a molded body 5, and a glass ribbon GR is formed from the molten glass GM in a molding step. Subsequently, the glass ribbon GR is formed to predetermined dimensions through an annealing step in an annealing furnace and a cutting step in a cutting device. 【0052】 In the homogenization process, the stirring tank 3 rotates the stirrer 8 while transferring the molten glass GM by the main body 7 (transfer process). In this case, the stirring tank 3 applies a voltage to the electrode section 16 to heat the main body 7 in order to control the temperature of the molten glass GM (direct electrical heating). At the same time, a coolant is supplied to the cooling mechanism 17. 【0053】 The refrigerant passes through the cooling pipe 18, cooling each flange portion 11, 12 and electrode portion 16. In this embodiment, the refrigerant flows in the order of electrode cooling portion 20 and flange cooling portion 19 of the cooling mechanism 17. However, it is not limited to this configuration, and the flange cooling portion 19 and electrode cooling portion 20 may be independent of each other without being connected. From the viewpoint of preventing the structure from becoming complicated and accurately cooling each flange portion 11, 12 and electrode portion 16, it is preferable that the refrigerant flows in the order of electrode cooling portion 20 and flange cooling portion 19 of the cooling mechanism 17, as in this embodiment. 【0054】 Figures 5 to 7 show other examples of a stirring tank. As shown in Figure 5, the stirring tank 3, similar to the example above, comprises a main body 7 through which molten glass GM flows, a stirrer 8 for stirring the molten glass GM in the main body 7, and a lid member 9 positioned on top of the main body 7. The stirring tank 3 is also held in place by a refractory material 10. 【0055】 As shown in Figures 6 and 7, each flange portion 11, 12 comprises an inner flange portion 23, an outer flange portion 24 integrally fixed to the outer circumference of the inner flange portion 23, an electrode portion 16, and a cooling mechanism 17. 【0056】 The inner flange portion 23 is made of, for example, platinum or a platinum alloy. The inner flange portion 23 is integrally formed with each end of the main body portion 7. The outer flange portion 24 is made of, for example, nickel or a nickel alloy and is annular (for example, circular). The outer flange portion 24 is integrally formed with the inner flange portion 23 by welding its inner circumference to the outer circumference of the inner flange portion 23. 【0057】 The electrode portion 16 is made of, for example, nickel or a nickel alloy in a plate shape. Similar to the example above, the electrode portion 16 has a predetermined width and is an elongated portion that protrudes radially outward from the outer circumference of the outer flange portion 24. 【0058】 As shown in Figures 5 and 6, the cooling mechanism 17 of each flange portion 11, 12 includes a plurality of cooling pipes 18. The number of cooling pipes 18 in the cooling mechanism 17 is not limited to this embodiment and can be appropriately set according to the dimensions of each flange portion 11, 12 and electrode portion 16. The cooling mechanism 17 is constructed by arranging cooling pipes 18 for transferring a refrigerant consisting of a gas such as air inside each flange portion 11, 12 and inside the electrode portion 16. The cooling pipes 18 are made of, for example, nickel, nickel alloy, copper, stainless steel, heat-resistant steel, etc. 【0059】 In this example, the cooling pipe 18 has a flange cooling section (not shown) and an electrode cooling section (not shown), similar to the example above. The flange cooling section is located inside the outer flange section 24, and the electrode cooling section is located inside the electrode section 16. 【0060】 According to the present embodiment described above, by covering each flange portion 11, 12 in the stirring tank 3 with the refractory 10, it is possible to prevent each flange portion 11, 12 from coming into contact with air. Thereby, oxidation and volatilization of platinum or a platinum alloy in each flange portion 11, 12 can be reduced. In addition, by covering each flange portion 11, 12 with the refractory 10, it is possible to prevent the temperature of the molten glass GM in the main body portion 7 from locally decreasing due to the cooling mechanism 17 provided in each flange portion 11, 12. 【0061】 Moreover, by using the amorphous refractory layer 10a for the refractory 10, the amorphous refractory layer 10a can be surely brought into contact with the surfaces of the disk-shaped flange portions 11, 12 protruding in the radial direction from the main body portion 7. 【0062】 Note that the present invention is not limited to the configuration of the above embodiment, nor is it limited to the above-described effects. The present invention can be variously modified without departing from the gist of the present invention. 【0063】 In the above embodiment, the disk-shaped flange portions 11, 12 are exemplified, but the structure of the flange portion is not limited thereto. For example, the lower flange portion 12 may be configured in a tapered (cylindrical) shape in which its diameter gradually expands downward. 【Explanation of Reference Numerals】 【0064】 3 Stirring tank 7 Main body portion 7a Outer peripheral surface of the main body portion 9 Lid member 10 Refractory 10a Amorphous refractory layer 10b Refractory brick layer 11 Upper flange portion 11a Upper surface of the upper flange portion 11b Lower surface of the upper flange portion 11c Outer peripheral surface of the upper flange portion 12 Lower flange portion 12a Upper surface of the lower flange portion 12b Lower surface of the lower flange portion Outer peripheral surface of the lower flange portion at 12c 13 Opening 17 Cooling mechanism GM Molten glass GR Glass ribbon

Claims

[Claim 1] A glass transfer apparatus comprising a stirring tank for stirring molten glass and a refractory material for holding the stirring tank, The stirring tank comprises a cylindrical main body and a lower flange portion provided at the lower part of the main body. The refractory material covers the outer circumferential surface of the main body, the upper surface of the lower flange, the lower surface of the lower flange, and the outer circumferential surface of the lower flange. The lower flange portion is equipped with a cooling mechanism for cooling the lower flange portion. The glass transfer device is characterized in that the refractory material comprises an amorphous refractory layer covering the upper surface of the lower flange portion, the lower surface of the lower flange portion, and the outer peripheral surface of the lower flange portion, and a refractory brick layer disposed outside the amorphous refractory layer. [Claim 2] The stirring tank is equipped with an upper flange portion located on the upper part of the main body, The glass transfer apparatus according to claim 1, wherein the refractory material covers the lower surface of the upper flange portion and the outer peripheral surface of the upper flange portion. [Claim 3] The main body has an opening that opens upward, The glass transfer device according to claim 2, further comprising a lid member that covers the upper surface of the upper flange portion and the opening of the main body portion. [Claim 4] The glass transfer apparatus according to claim 2 or 3, wherein the upper flange portion is provided with a cooling mechanism for cooling the upper flange portion. [Claim 5] A method for manufacturing a glass article, characterized by comprising a transfer step of transferring molten glass using a glass transfer device described in any one of claims 1 to 3.

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