Glass manufacturing apparatus and method for manufacturing glass article

Abstract

The present invention prevents deformation of a container in which molten glass is stored. A glass manufacturing apparatus 1 is provided with a melting pot 2 in which molten glass GM, which is obtained by melting a glass raw material GR, is retained in a housing part 5. The melting pot 2 has a lined metal part 9 that constitutes the housing part 5, and a holding part 10 that holds the lined metal part 9 from the outside. The glass manufacturing apparatus 1 is additionally provided with: a first decompression part 12 which decompresses the housing part 5; and a lid part 7 which closes the housing part 5 by closing the holding part 10.

Description

Glass manufacturing apparatus and method for manufacturing glass articles

[0001] The present invention relates to a glass manufacturing apparatus and a method for manufacturing a glass article.

[0002] A typical method for producing a glass article includes a melting step in which glass raw materials are heated to produce molten glass, a fining step in which the molten glass is degassed, a stirring step in which the molten glass is homogenized, and a forming step in which a glass article is formed from the molten glass.

[0003] For example, Patent Document 1 discloses a so-called batch production furnace equipped with a melting pot made of a heat-resistant metal containing platinum as a glass melting furnace used in a melting step, which is configured to perform a melting step, a fining step, and a stirring step in the melting pot (see paragraph 0004 and FIG. 12 of the same document).

[0004] The present inventors have investigated a method for reducing the pressure inside the melting pot in order to enhance the degassing effect when the molten glass is subjected to a fining process in the melting pot. For example, Patent Document 2 discloses a method for melting powdered glass in a refractory container using a vacuum heating furnace equipped with a heating element.

[0005] JP 2005-154216 A JP 2003-327434 A

[0006] The inventors have discovered a problem in that when a refractory container made of, for example, platinum or a platinum alloy is used, the refractory container may be deformed when heated under reduced pressure in the above-mentioned vacuum heating furnace.

[0007] An object of the present invention is to prevent deformation of a container that contains molten glass.

[0008] (1) The present invention is intended to solve the above-mentioned problems, and is a glass manufacturing apparatus including a melting pot that stores molten glass obtained by melting glass raw materials in a storage section, wherein the melting pot has a lining metal part that constitutes the storage section and a holding part that holds the lining metal part from the outside, and further has a first decompression part that decompresses the storage section, and a lid part that closes the holding part to thereby close the storage section.

[0009] According to this configuration, by holding the lining metal part in the storage section of the melting pot, which is a container for storing molten glass, with the holding part, the lining metal part, which is the part that comes into contact with the molten glass, can be reinforced by the holding part.

[0010] In addition, by closing the holding portion with the lid, the melting pot can be closed without applying the load of the lid to the lining metal portion. As a result, even when the accommodation portion is depressurized by the first depressurization portion, deformation of the lining metal portion as the accommodation portion can be prevented.

[0011] (2) In the glass manufacturing apparatus described in (1) above, the melting pot may have an input section provided above the storage section, through which the glass raw material is input into the storage section from an input port, and a discharge section provided below the storage section, through which the molten glass stored in the storage section is discharged to a next process, and the lid section may close the input port of the input section.

[0012] According to this configuration, by charging glass frits from an input part provided above the container part, the glass frits can be dropped by their own weight and easily accommodated in the container part, and the molten glass can be easily discharged by its own weight to the next process from a discharge part provided below the container part.

[0013] (3) In the glass manufacturing apparatus described in (1) or (2) above, the melting pot may have an outer metal cladding part on the outside of the holding part, which makes it possible to suitably reduce the pressure in the container part and improve the strength of the melting pot.

[0014] (4) In the glass manufacturing apparatus according to any one of (1) to (3) above, the first pressure reducing section may be connected to the input section.

[0015] According to this configuration, the first pressure reducing section connected to the input section can reliably reduce the pressure in the storage section without complicating the structure of the storage section.

[0016] (5) In the glass manufacturing apparatus described in any one of (1) to (4) above, the input section to which the first pressure reducing section is connected may not be provided with the lining metal section.

[0017] In this way, even if the inserting portion does not have a metal lining portion, the retaining portion can effectively prevent deformation of the metal lining portion.

[0018] (6) In the glass manufacturing apparatus described in any one of (1) to (5) above, the holding portion has a large diameter portion that holds the storage portion, a small diameter portion that constitutes the input portion, and a variable diameter portion that connects the large diameter portion and the small diameter portion, and the small diameter portion and the variable diameter portion may not be provided with the lining metal portion.

[0019] According to this configuration, it is possible to prevent foreign matter that has evaporated from the lining metal portion and aggregated from dropping into and contaminating the molten glass.

[0020] (7) In the glass manufacturing apparatus described in any one of (3) to (6) above, the outer metal lining part and the inner metal lining part are connected to form a storage space for accommodating the holding part therein, the first pressure reduction part is connected to the inner metal lining part, and the lid part may further have a second pressure reduction part that closes the holding part via the outer metal lining part, is connected to the outer metal lining part, and reduces the pressure in the storage space.

[0021] According to this configuration, by reducing the pressure in the accommodation space of the holding portion by the second pressure reducing portion, it is possible to prevent the metal lining portion from being deformed so as to separate from the holding portion.

[0022] (8) The glass manufacturing apparatus according to any one of (2) to (7) above may further include a heating element disposed around the melting pot and refractory bricks covering the melting pot and the heating element, wherein the input section has an exposed portion exposed from the refractory bricks, and the first pressure reducing section is connected to the exposed portion.

[0023] According to this configuration, the exposed portion of the input section exposed to the outside of the firebrick is at a lower temperature than the storage section, and therefore, by connecting the first pressure reduction section to this exposed portion, deformation of the first pressure reduction section can be prevented.

[0024] (9) The present invention is a method for manufacturing a glass article using the glass manufacturing apparatus described in any one of (1) to (8) above, the method comprising: a charging step of charging the glass raw material from the charging part into the storage part of the melting pot; a melting step of heating the glass raw material to melt the glass raw material; a stirring step of inserting a stirring member from the charging port and stirring the molten glass; a fining step of degassing the molten glass after the stirring step; and a discharge step of discharging the molten glass from the discharge part to a subsequent step after the fining step, wherein the storage part is under atmospheric pressure during the charging step, the melting step, and the stirring step, and the storage part is under reduced pressure during the fining step.

[0025] According to this configuration, the pressure in the container is reduced only during the fining process, rather than during all of the above processes, thereby minimizing the time during which negative pressure acts on the container, and thereby more effectively preventing deformation of the metal lining of the container.

[0026] (10) The present invention is a method for manufacturing a glass article using the glass manufacturing apparatus described in (7) or (8) above, the method comprising: a charging step of charging the glass frit from the charging part into the storage part of the melting pot; a melting step of heating the glass frit to melt the glass frit; a stirring step of inserting a stirring member from the charging port and stirring the molten glass; a fining step of degassing the molten glass after the stirring step; and a discharge step of discharging the molten glass from the discharge part to a next process after the fining step, wherein the first pressure reducing part and the second pressure reducing part are controlled in the fining step so that a pressure in the storage space is lower than a pressure in the storage part.

[0027] According to this configuration, by making the pressure in the accommodation space lower than the pressure in the accommodation portion, it is possible to prevent the metal lining portion of the accommodation portion from deforming in a direction away from the holding portion.

[0028] (11) In the method for manufacturing a glass article described in (10) above, the storage section may be under atmospheric pressure during the loading step, the melting step, and the stirring step, and the storage space may be under reduced pressure during the loading step, the melting step, and the stirring step.

[0029] According to this configuration, by reducing the pressure in the storage space in all of the above steps, deformation of the lining metal part of the storage part can be effectively prevented. Furthermore, by keeping the storage part under atmospheric pressure in the charging step, melting step, and stirring step, the effect of preventing deformation of the lining metal part of the storage part can be further enhanced.

[0030] According to the present invention, deformation of a container that contains molten glass can be prevented.

[0031] Fig. 1 is a cross-sectional view of a glass manufacturing apparatus according to a first embodiment; Fig. 2 is a cross-sectional view showing an upper part of a melting pot; Fig. 3 is a flowchart showing a method for manufacturing a glass article; Fig. 4 is a cross-sectional view showing a charging step in the method for manufacturing a glass article; Fig. 5 is a cross-sectional view showing a stirring step in the method for manufacturing a glass article; Fig. 6 is a cross-sectional view of a glass manufacturing apparatus according to a second embodiment; Fig. 7 is a cross-sectional view of a glass manufacturing apparatus according to a third embodiment; Fig. 8 is a cross-sectional view of a glass manufacturing apparatus according to a fourth embodiment; Fig. 9 is a cross-sectional view of a glass manufacturing apparatus according to a fifth embodiment.

[0032] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Figures 1 to 5 show a first embodiment of a glass manufacturing apparatus and a method for manufacturing a glass article according to the present invention.

[0033] As shown in Fig. 1, the glass manufacturing apparatus 1 is configured as a melting furnace that heats glass raw materials to produce molten glass GM. The glass manufacturing apparatus 1 includes a melting pot 2 that stores molten glass GM, a heating device 3 that heats the melting pot 2, and a furnace wall portion 4 that covers the melting pot 2.

[0034] The melting pot 2 includes a container 5 for containing glass raw materials and molten glass GM, an input section 6 for inputting glass raw materials into the container 5, a lid 7 for closing the input section 6, and a discharge section 8 for discharging the molten glass GM contained in the container 5.

[0035] In addition, the melting pot 2 includes an inner metal lining part 9 that constitutes the storage part 5 and the input part 6, a holding part 10 that holds this inner metal lining part 9 from the outside, an outer metal lining part 11 that covers the outer surface of the holding part 10, and pressure reduction parts 12, 13 for reducing the pressure in the melting pot 2.

[0036] The storage section 5 is a container having a predetermined volume. The storage section 5 is composed of a part of an inner metal lining section 9, a part of a holding section 10, and a part of an outer metal lining section 11. The storage section 5 is supported by a support base 14 provided inside the furnace wall section 4.

[0037] 1 and 2 , the input section 6 is provided integrally with the storage section 5 above the storage section 5. The input section 6 is a cylindrical section extending in the vertical direction, but the shape of the input section 6 is not limited to this embodiment. The input section 6 is composed of a part of the inner metal lining section 9, a part of the holding section 10, and a part of the outer metal lining section 11.

[0038] The upper part of the charging part 6 protrudes upward from the furnace wall part 4, and the lower part of the charging part 6 is provided inside the furnace wall part 4. The upper part of the charging part 6 is an exposed part exposed upward from the upper part of the furnace wall part 4. The pressure reducing parts 12 and 13 are connected to this exposed part. The charging part 6 has, at its upper end, a charging port 6a through which glass raw material can be charged. The charging port 6a has a receiving part 15 capable of supporting the lid part 7. The receiving part 15 is constituted by a circular plate having a through-hole in the center, but is not limited to this shape.

[0039] The lid 7 is configured to be detachable from the input port 6a of the input unit 6. The lid 7 is configured from a metal plate such as stainless steel. The lid 7 has an area larger than the opening area of ​​the input port 6a. The lid 7 is supported by the holder 10 via a receiving portion 15. In other words, the lid 7 can close the storage unit 5 communicating with the input unit 6 by closing the upper end of the holder 10.

[0040] As shown in FIG. 1, the discharge part 8 is provided integrally with the storage part 5 below the storage part 5. The discharge part 8 is a tubular part extending in the vertical direction. The discharge part 8 is made of a metal such as platinum or a platinum alloy. The discharge part 8 has a heating means (not shown) such as a heating element, induction heating, or electric heating in its middle part, and has an outlet (not shown) for the molten glass GM at its lower end. A forming device (not shown) capable of forming a predetermined formed product from the molten glass GM is provided below the discharge part 8.

[0041] The metal lining part 9 is a cylindrical part with a bottom made of, for example, platinum or a platinum alloy. The metal lining part 9 has a certain thickness and is fixed to the inner surface of the holding part 10. The thickness of the metal lining part 9 is preferably 0.3 mm or more and 3 mm or less.

[0042] As shown in Figure 1, the lining metal part 9 includes a first lining metal part 16 that constitutes the storage section 5, a second lining metal part 17 that constitutes the input section 6, and an intermediate lining metal part 18 that is provided between the first lining metal part 16 and the second lining metal part 17.

[0043] The first lining metal portion 16 has a side wall portion 16a and a bottom wall portion 16b. The side wall portion 16a is a cylindrical portion having a predetermined inner diameter, but the shape of the side wall portion 16a is not limited to this embodiment. The bottom wall portion 16b closes the lower end of the side wall portion 16a. The upper end of the discharge portion 8 is connected to the center of the bottom wall portion 16b.

[0044] 1 and 2 , the second metal lining part 17 is provided integrally with the intermediate metal lining part 18 above the first metal lining part 16. The second metal lining part 17 is a cylindrical part having a smaller diameter than the first metal lining part 16, but the shape of the second metal lining part 17 is not limited to this embodiment. An upper end part 17a of the second metal lining part 17 forms the insertion opening 6a of the insertion part 6.

[0045] The intermediate metal lining part 18 connects the first metal lining part 16 and the second metal lining part 17, which have different diameters. The intermediate metal lining part 18 is configured in a cylindrical shape whose diameter increases from the second metal lining part 17 side toward the first metal lining part 16 side. The intermediate metal lining part 18 has a curved shape that is convex outward.

[0046] The retaining portion 10 has a function of maintaining the shape of the inner metal lining portion 9 and the outer metal lining portion 11 so as to prevent deformation. The retaining portion 10 is a cylindrical portion with a bottom made of a refractory material such as alumina, mullite, or alumina zirconia. The thickness of the retaining portion 10 is preferably 5 mm or more and 50 mm or less.

[0047] As shown in Figure 1, the holding section 10 includes a first holding section 19 that holds the storage section 5, a second holding section 20 that holds the input section 6, and an intermediate holding section 21 that is provided between the first holding section 19 and the second holding section 20.

[0048] The first holding portion 19 includes a side wall portion 19a and a bottom wall portion 19b. The side wall portion 19a is a cylindrical portion (large diameter portion) with a diameter larger than that of the input portion 6, but the shape of the side wall portion 19a is not limited to this embodiment. The side wall portion 16a of the first lining metal portion 16 is fixed to the inner surface of the side wall portion 19a. The bottom wall portion 19b closes the lower end of the side wall portion 19a. The bottom wall portion 16b of the first lining metal portion 16 is fixed to the inner surface of the bottom wall portion 19b. The discharge portion 8 penetrates the center of the bottom wall portion 19b.

[0049] The second retaining portion 20 is a cylindrical portion (small diameter portion) having a smaller diameter than the first retaining portion 19, but the shape of the second retaining portion 20 is not limited to this embodiment. The second lining metal portion 17 is fixed to the inner surface of the second retaining portion 20.

[0050] An end surface (hereinafter referred to as the "top surface") 20a of the upper end of the second holding portion 20 functions as a support portion that supports the lid portion 7. The top surface 20a is covered with a part of the outer metal cladding portion 11. The top surface 20a supports the receiving portion 15. The outer diameter of the top surface 20a is smaller than the diameter of the receiving portion 15.

[0051] The intermediate retaining portion 21 is a variable diameter portion that connects the first retaining portion 19 as a large diameter portion and the second retaining portion 20 as a small diameter portion. Specifically, the intermediate retaining portion 21 is a tubular portion that increases in diameter from the second retaining portion 20 side toward the first retaining portion 19 side. The intermediate retaining portion 21 also has a curved shape that is convex outward. The intermediate lining metal portion 18 is fixed to the inner surface of the intermediate retaining portion 21.

[0052] The outer metal part 11 is a cylindrical part with a bottom made of, for example, platinum or a platinum alloy. The outer metal part 11 has a certain thickness and is fixed to the outer surface of the holding part 10. The thickness of the outer metal part 11 is preferably 0.3 mm or more and 3 mm or less.

[0053] The outer metal part 11 includes a first outer metal part 22 corresponding to the storage section 5, a second outer metal part 23 corresponding to the input section 6, and an intermediate outer metal part 24 provided between the first outer metal part 22 and the second outer metal part 23.

[0054] The first outer metal portion 22 has a side wall portion 22a and a bottom wall portion 22b. The side wall portion 22a is a cylindrical portion having a predetermined inner diameter, but the shape of the side wall portion 22a is not limited to this embodiment. The side wall portion 22a is fixed to the outer surface of the side wall portion 19a of the first holding portion 19. The bottom wall portion 22b closes the lower end of the side wall portion 22a. The bottom wall portion 22b is fixed to the outer surface of the bottom wall portion 19b of the first holding portion 19. The discharge portion 8 penetrates the center of the bottom wall portion 22b.

[0055] The second outer metal part 23 is a cylindrical part having a smaller diameter than the first outer metal part 22, but the shape of the second outer metal part 23 is not limited to this embodiment. The second outer metal part 23 is fixed to the outer surface of the second retaining part 20. As shown in Fig. 2 , the second outer metal part 23 has a top surface covering part 23a that covers the top surface 20a of the second retaining part 20. The top surface covering part 23a is connected to the upper end part 17a of the second inner metal part 17.

[0056] The intermediate outer metal portion 24 connects the first outer metal portion 22 and the second outer metal portion 23, which have different diameters. The intermediate outer metal portion 24 is a tubular portion whose diameter increases from the second outer metal portion 23 side toward the first outer metal portion 22 side. The intermediate outer metal portion 24 is fixed to the outer surface of the intermediate holding portion 21.

[0057] In this embodiment, as described above, the entire inner and outer surfaces of the retaining portion 10 are covered by the inner metal portion 9 and the outer metal portion 11. In other words, the inner metal portion 9 and the outer metal portion 11 are connected via the top surface covering portion 23a to form an accommodation space 25 therein that accommodates the retaining portion 10. This accommodation space 25 is a space sealed by the inner metal portion 9 and the outer metal portion 11.

[0058] The pressure reducing sections 12, 13 include a first pressure reducing section 12 and a second pressure reducing section 13. The first pressure reducing section 12 reduces the pressure in the internal spaces of the storage section 5 and the input section 6. The second pressure reducing section 13 reduces the pressure in the storage space 25 of the holding section 10 formed between the inner metal lining section 9 and the outer metal lining section 11.

[0059] The first pressure reducing section 12 has a first pipe 26 connected to the input section 6. The first pipe 26 is made of, for example, platinum or a platinum alloy, but is not limited thereto and may be made of other metals. The end of the first pipe 26 passes through the second outer metal lining section 23 and the second holding section 20 and is connected to the second inner metal lining section 17. The first pipe 26 has an on-off valve (not shown) in its middle. The first pipe 26 is also connected to a first suction device (not shown) constituted by, for example, a vacuum pump.

[0060] The second pressure reducing section 13 has a second pipe 27 connected to the input section 6. The second pipe 27 is made of platinum or a platinum alloy, but may be made of other metals as well. An end of the second pipe 27 is connected to the second outer metal part 23 and communicates with the storage space 25. The second pipe 27 has an on-off valve (not shown) in its middle. The second pipe 27 is also connected to a second suction device (not shown) that is, for example, a vacuum pump.

[0061] 1, the heating device 3 is disposed in the space formed between the melting pot 2 and the furnace wall 4. The heating device 3 has one or more heating elements 28 disposed so as to surround the periphery of the melting pot 2.

[0062] 1, the furnace wall 4 is hollow and has a space therein for accommodating the melting pot 2 and the heating device 3. The furnace wall 4 is made of refractory bricks such as alumina, mullite, or alumina-zirconia. The furnace wall 4 has an upper wall 4a, a side wall 4b, and a bottom wall 4c.

[0063] The top wall 4a is supported by the upper part of the side wall 4b. The top wall 4a supports a part of the heating element 28 of the heating device 3. The top wall 4a has an insertion hole 4a1 through which the input part 6 of the melting pot 2 is inserted. The side wall 4b covers the accommodation part 5 and the heating device 3 from the sides. The bottom wall 4c supports the support table 14 at its center. The discharge part 8 penetrates the center of the bottom wall 4c.

[0064] The glass composition of the molten glass GM contains, for example, in mass %, SiO2 0 to 15%, TiO2 5 to 50%, and La2O3 5 to 50%.

[0065] Hereinafter, a description will be given of a method for manufacturing a glass article using the above-described glass manufacturing apparatus 1. As shown in Fig. 3 , this method includes a charging step S1, a melting step S2, a stirring step S3, a fining step S4, a discharging step S5, and a forming step S6.

[0066] In addition, the method includes a step of depressurizing the melting pot 2 using depressurization units 12, 13 (depressurization step). The depressurization step includes a first depressurization step using the first depressurization unit 12 and a second depressurization step using the second depressurization unit 13. The first depressurization step is performed simultaneously with the fining step S4. The second depressurization step is performed continuously throughout all steps from the introduction step S1 to the molding step S6. That is, in the second depressurization step, the on-off valve of the second piping 27 of the second depressurization unit 13 is opened simultaneously with or before the introduction step S1, and the second suction device starts suctioning gas from the accommodation space 25 in the melting pot 2.

[0067] As shown in Fig. 4, in the charging step S1, in a state where the cover part 7 is removed from the charging part 6, the frit GR is charged from the charging port 6a of the charging part 6. The frit GR charged from the charging port 6a falls into the storage part 5 and is stored in the storage part 5.

[0068] Thereafter, the lid portion 7 is placed on the receiving portion 15 of the input portion 6, thereby closing the input port 6a of the input portion 6. The lid portion 7 is supported by the holding portion 10 via the receiving portion 15 and the top surface covering portion 23a of the second outer metal portion 23. In other words, the top surface 20a of the second holding portion 20 is closed by the lid portion 7 via the top surface covering portion 23a of the second outer metal portion 23 and the receiving portion 15.

[0069] When the throwing step S1 is completed, the melting step S2 is carried out. In the melting step S2, the melting pot 2 is heated by the heating device 3. As a result, the glass frit GR in the container 5 is melted, and the molten glass GM is produced (see FIG. 1). The heating device 3 continues to heat the melting pot 2 even after the molten glass GM is produced. Incidentally, the heating of the melting pot 2 by the heating device 3 may also be continued in the throwing step S1. In this case, the heating of the melting pot 2 in the throwing step S1 may be continued at a temperature lower than the heating temperature in the melting step S2.

[0070] As shown in Fig. 5, in stirring process S3, remove lid part 7 from input part 6, then insert stirring element 29 from input port 6a, and stir molten glass GM by this stirring element 29. Stirring element 29 is configured in a rod shape, and has blade part 29a at its tip. In stirring process S3, stir element 29 is rotated around its axis, and blade part 29a is rotated in molten glass GM, thereby stirring molten glass GM homogeneously.

[0071] After the stirring step S3 is completed, the stirring member 29 is removed from the melting pot 2. Next, the charging port 6a of the charging part 6 is closed with the lid 7. After that, the first depressurization step and the fining step S4 are performed. In the first depressurization step, the on-off valve of the first piping 26 is opened, and the gas in the internal space of the storage part 5 and the charging part 6 is sucked out by the first suction device. In the first depressurization step, the pressure is reduced to 5×10 3 Pa or more 5×10 4 It is preferable to reduce the pressure in the internal spaces of the storage section 5 and the input section 6 to 10 Pa or less.

[0072] In the fining step S4, the first decompression step and the second decompression step are maintained, and the molten glass GM is subjected to degassing treatment. In the fining step S4, the bubbles generated in the molten glass GM are released into the space above the liquid surface of the molten glass GM in the melting pot 2.

[0073] In the second decompression step, which is carried out simultaneously with this clarification step S4, it is preferable to control the first decompression section 12 and the second decompression section 13 so that the pressure in the storage space 25 is lower than the pressure in the internal space of the storage section 5 and the input section 6.

[0074] That is, the difference in pressure between the first depressurization step and the second depressurization step ("pressure in the first depressurization step" - "pressure in the second depressurization step") is 5 x 10 2 Pa or more 5×10 4 It is preferable to perform the first depressurization step and the second depressurization step so that the pressure becomes 0.05 Pa or less.

[0075] As described above, the first depressurization step is carried out simultaneously with the fining step S4, but is not carried out in the other steps S1 to S3, S5, and S6. That is, it is preferable that the internal spaces of the storage section 5 and the input section 6 are under reduced pressure only in the fining step S4, and are under atmospheric pressure in the input step S1, the melting step S2, the stirring step S3, the discharging step S5, and the molding step S6.

[0076] On the other hand, the second depressurization step is preferably carried out in all steps S1 to S6 as described above. That is, it is preferable that the accommodation space 25 is kept under reduced pressure in all steps from the introduction step S1 to the molding step S6.

[0077] In the discharge step S5, after the fining step S4, the molten glass GM is discharged from the discharge part 8 to the next forming step S6. That is, the discharge part 8 is heated by a heating means not shown, and the glass solidified inside the discharge part 8 is melted, so that the molten glass GM in the storage part 5 is discharged from the discharge port.

[0078] In the forming step S6, the molten glass GM discharged from the discharge part 8 is supplied to a forming device. The forming device forms the molten glass GM to manufacture a glass article having a predetermined shape.

[0079] According to the glass manufacturing apparatus 1 and the manufacturing method of a glass article according to the present embodiment described above, the lining metal part 9 of the melting pot 2 storing the molten glass GM is held by the holding part 10, so that the lining metal part 9 can be reinforced by the holding part 10. As a result, even when the first depressurization step is carried out in the fining step S4, deformation of the lining metal part 9 can be prevented.

[0080] Furthermore, by configuring the melting pot 2 so that the lid 7 closes the holding portion 10, the melting pot 2 can be closed by the lid 7 without applying the load of the lid 7 to the lining metal portion 9. This prevents the lining metal portion 9 from being deformed by the load of the lid 7.

[0081] Furthermore, by controlling the pressure in the accommodation space 25 as described above in the second decompression step, a negative pressure is generated in the accommodation space 25, and it is possible to prevent the metal lining part 9 from deforming so as to separate from the holding part 10. This allows the holding part 10 to preferably maintain the shape of the metal lining part 9.

[0082] 6 shows a second embodiment of the glass manufacturing apparatus. In the melting pot 2 according to this embodiment, the upper end 17a of the second inner metal lining part 17 is not connected to the top surface covering part 23a of the second outer metal lining part 23. Furthermore, the melting pot 2 does not include the second pressure reducing part 13 of the first embodiment.

[0083] The upper end 17a of the second lining metal part 17 is located midway on the inner surface of the second holding part 20. Specifically, the upper end 17a of the second lining metal part 17 is located below the first piping 26 of the first pressure reducing part 12. In other words, the second lining metal part 17 is not provided in the part of the input part 6 where the first piping 26 is connected.

[0084] 7 shows a third embodiment of a glass manufacturing apparatus. The lining metal part 9 of the melting pot 2 according to this embodiment does not include the second lining metal part 17 and the intermediate lining metal part 18 of the first embodiment. In other words, the lining metal part 9 is not provided on the inner surface of the second holding part 20 and the inner surface of the intermediate holding part 21 of the holding part 10. Furthermore, the melting pot 2 does not include the outer lining metal part 11, the second pressure reducing part 13, and the receiving part 15 of the first embodiment. The input part 6 of the melting pot 2 according to this embodiment is formed only by the second holding part 20 of the holding part 10. The input port 6a of the input part 6 is formed by the inner edge part of the top surface 20a of the second holding part 20.

[0085] As described above, by reducing the amount of the lining metal part 9 used inside the melting pot 2, it is possible to prevent the incorporation of platinum-derived foreign matter that has evaporated and aggregated from the lining metal part 9 into the molten glass GM. Note that the amount of the lining metal part 9 may be further reduced by positioning the upper end of the first lining metal part 16 in the middle of the inner surface of the first holding part 19.

[0086] 8 shows a fourth embodiment of the glass manufacturing apparatus. The melting pot 2 according to this embodiment is divided into a plurality of sections. That is, the melting pot 2 includes a first section 2a constituting the container section 5, a second section 2b constituting the input section 6, and a third section 2c as an intermediate section connecting the first section 2a and the second section 2b.

[0087] The lining metal part 9 is configured by separating a first lining metal part 16, a second lining metal part 17 and an intermediate lining metal part 18 so as to correspond to the above-mentioned respective parts 2a to 2c.

[0088] The holding portion 10 is configured by separating a first holding portion 19, a second holding portion 20, and an intermediate holding portion 21 so as to correspond to the above-mentioned respective portions 2a to 2c.

[0089] The outer metal portion 11 is configured by separating a first outer metal portion 22, a second outer metal portion 23, and an intermediate outer metal portion 24 so as to correspond to each of the above-mentioned portions 2a to 2c.

[0090] The first outer metal portion 22 has a top surface covering portion 22c that covers the top surface of the first retaining portion 19. The top surface covering portion 22c is connected to the upper end portion of the first inner metal portion 16. As a result, the first inner metal portion 16 and the first outer metal portion 22 form a first housing space 25a that houses the first retaining portion 19.

[0091] The second outer metal part 23 has, in addition to the top surface covering part 23a, a bottom surface covering part 23b that covers the bottom surface of the second retaining part 20. The bottom surface covering part 23b is connected to the bottom end part of the second inner metal part 17. As a result, the second inner metal part 17 and the second outer metal part 23 form a second accommodation space 25b that accommodates the second retaining part 20.

[0092] The intermediate external metal portion 24 has a top surface covering portion 24 a that covers the top surface of the intermediate holding portion 21 and a bottom surface covering portion 24 b that covers the bottom surface of the intermediate holding portion 21 .

[0093] The top surface covering portion 24a is in contact with the bottom surface covering portion 23b of the second exterior metal portion 23. The top surface covering portion 24a and the bottom surface covering portion 23b of the second exterior metal portion 23 may be integrated by welding. Although the metal portion has a two-layer structure with the top surface covering portion 24a and the bottom surface covering portion 23b, it is also possible to use a single-layer structure (partition structure) in which the bottom surface side of the metal portion in the single layer is the top surface covering portion 24a and the top surface side is the bottom surface covering portion 23b.

[0094] The lower surface covering portion 24b is in contact with the top surface covering portion 22c of the first outer metal portion 22. The lower surface covering portion 24b and the top surface covering portion 22c of the first outer metal portion 22 may be integrated by welding. Although the metal portion has a two-layer structure consisting of the lower surface covering portion 24b and the top surface covering portion 22c, it is also possible to use a single-layer structure (partition structure) in which the lower surface side of the metal portion in the single layer is the top surface covering portion 22c and the upper surface side is the lower surface covering portion 24b.

[0095] The top surface covering portion 24a is connected to the upper end of the intermediate metal lining portion 18. The bottom surface covering portion 24b is connected to the lower end of the intermediate metal lining portion 18. As a result, the intermediate metal lining portion 18 and the intermediate outer metal lining portion 24 form an intermediate storage space 25c that stores the intermediate holding portion 21.

[0096] In the present embodiment, the second pressure reducing unit 13 includes a plurality of second pipes 27a to 27c. Each of the second pipes 27a to 27c is connected to the first portion 2a, the second portion 2b, and the third portion 2c, respectively. That is, the second pressure reducing unit 13 includes the second pipe 27a that reduces the pressure in the first housing space 25a, the second pipe 27b that reduces the pressure in the second housing space 25b, and the second pipe 27c that reduces the pressure in the intermediate housing space 25c.

[0097] According to this embodiment, the melting pot 2 is provided with a plurality of accommodation spaces 25a to 25c, and each accommodation space 25a to 25c is depressurized by the second pipes 27a to 27c of the second depressurization section 13 (second depressurization step), thereby enabling each accommodation space 25a to 25c to be depressurized with high precision, thereby making it possible to more effectively prevent deformation of the lining metal part 9.

[0098] 9 shows a fifth embodiment of a glass manufacturing apparatus. In the melting pot 2 according to this embodiment, the lid 7 has an exhaust port 31 and a hole 7a through which the shaft of the stirring member 29 is inserted. The stirring member 29 is inserted through the hole 7a in the lid 7. The first pipe 26 is connected to a first suction device (not shown) and a gas supply mechanism (not shown) such as a gas cylinder, and the connection destination can be selected by an on-off valve.

[0099] The gas supplied from the gas supply mechanism is preferably an inert gas, which can suppress oxidation of the glass.

[0100] The exhaust unit 31 has a third pipe 32 that exhausts gas in the internal spaces of the storage unit 5 and the input unit 6 to the outside. The third pipe 32 is made of, for example, platinum or a platinum alloy, but is not limited to this and may be made of other metals. An end of the third pipe 32 penetrates the lid unit 7. The third pipe 32 has an on-off valve (not shown) in its middle.

[0101] In this embodiment, after the input port 6a of the input unit 6 is closed with the lid 7, the gas in the internal space of the storage unit 5 and the input unit 6 is replaced with an inert gas (gas replacement step) before the melting step S2 is performed. In this case, first, the on-off valve of the first pipe 26 is opened, and the on-off valve of the third pipe 32 is closed, and the gas in the internal space of the storage unit 5 and the input unit 6 is sucked out by the first suction device. Next, the connection destination of the first pipe 26 is changed to a gas supply mechanism, and inert gas is introduced from the gas supply mechanism into the internal space of the storage unit 5 and the input unit 6. By repeating this process, the gas in the internal space of the storage unit 5 and the input unit 6 can be replaced with the inert gas. After the internal space of the storage unit 5 and the input unit 6 has been replaced with the inert gas, the melting step S2 is performed.

[0102] After the internal spaces of the storage section 5 and the input section 6 have been replaced with the inert gas, the first pipe 26 is connected to the gas supply mechanism to continue supplying the inert gas, and the on-off valve of the third pipe 32 is opened to discharge the inert gas to the outside through the exhaust section 31. This makes it possible to maintain the internal spaces of the storage section 5 and the input section 6 in an inert atmosphere.

[0103] In this embodiment, the shaft of the stirring member 29 is inserted into the hole 7a of the lid portion 7. Therefore, in the stirring step S3, the molten glass GM can be stirred by the stirring member 29 without removing the lid portion 7. In addition, since the lid portion 7 can maintain the state in which the input portion 6 is closed, the internal space of the storage portion 5 and the input portion 6 can be maintained in an inert atmosphere.

[0104] In this embodiment, after the stirring step S3 is completed, the on-off valve of the third pipe 32 is closed and the first pipe 26 is connected to the first suction device. Thereafter, the first depressurization step and the clarification step S4 are performed.

[0105] As described above, when the internal space of the storage section 5 and the input section 6 is replaced with an inert atmosphere before the melting step S2, it is preferable that the internal space of the storage section 5 and the input section 6 be an inert atmosphere from the melting step S2 to the molding step S6.

[0106] The present invention is not limited to the configuration of the above-described embodiment, nor is it limited to the above-described effects. The present invention can be modified in various ways without departing from the spirit of the present invention.

[0107] In the melting pot 2 according to the above embodiment, a slit may be formed on the outer or inner surface of the holding part 10 so that the second pressure reducing part 13 can effectively reduce the pressure in the accommodation space 25 .

[0108] In the above embodiment, the outer metal member 11 is made of platinum or a platinum alloy, but the present invention is not limited to this configuration. For example, the second outer metal member 23 formed on the exposed portion of the input port 6 may be made of stainless steel or another metal.

[0109] In the above embodiment, the second depressurization step is performed in all steps from the introducing step S1 to the molding step S6, but the present invention is not limited to this configuration. For example, the second depressurization step may be performed only in the fining step S4.

[0110] REFERENCE SIGNS LIST 1 Glass manufacturing apparatus 2 Melting pot 4 Furnace wall (firebrick) 5 Storage section 6 Input section 6a Input port 7 Lid section 8 Discharge section 9 Lining metal section 10 Holding section 11 Outer lining metal section 12 First reduced pressure section 13 Second reduced pressure section 19 First holding section (large diameter section) 20 Second holding section (small diameter section) 21 Intermediate holding section (variable diameter section) 25 Storage space 28 Heating element GR Glass raw material GM Molten glass S1 Input step S2 Melting step S3 Stirring step S4 Refining step S5 Discharge step

Claims

1. A glass manufacturing apparatus having a melting pot for storing molten glass obtained by melting glass raw materials in a storage section, wherein the melting pot has a lining metal part that constitutes the storage section and a holding part that holds the lining metal part from the outside, a first decompression part that reduces the pressure in the storage section, and a lid part that closes the holding part to thereby close the storage section.

2. The glass manufacturing apparatus according to claim 1, characterized in that the melting pot has: an input section, provided above the storage section, for inputting the glass raw material into the storage section through an input port; and a discharge section, provided below the storage section, for discharging the molten glass stored in the storage section to a next process; and the lid section closes the input port of the input section.

3. The glass manufacturing apparatus according to claim 2, characterized in that the melting pot has an external metal part on the outside of the holding part.

4. The glass manufacturing apparatus according to claim 2 or 3, characterized in that the first pressure reducing section is connected to the input section.

5. The glass manufacturing apparatus according to claim 4, characterized in that the input section to which the first pressure reducing section is connected is not provided with the lining metal section.

6. The glass manufacturing apparatus according to claim 5, characterized in that the holding portion has a large diameter portion that holds the storage portion, a small diameter portion that constitutes the input portion, and a variable diameter portion that connects the large diameter portion and the small diameter portion, and the small diameter portion and the variable diameter portion are not provided with the lining metal portion.

7. The glass manufacturing apparatus described in claim 3, characterized in that the outer metal part and the inner metal part are connected to form a storage space for accommodating the holding part therein, the first pressure reduction part is connected to the inner metal part, and the cover part closes the holding part via the outer metal part and has a second pressure reduction part connected to the outer metal part and for reducing the pressure in the storage space.

8. The glass manufacturing apparatus according to claim 4, further comprising: a heating element disposed around the melting pot; and firebricks covering the melting pot and the heating element; wherein the input portion has an exposed portion exposed from the firebricks; and the first pressure reducing portion is connected to the exposed portion.

9. A method for manufacturing a glass article using the glass manufacturing apparatus according to claim 2 or 3, comprising: a feeding step of feeding the glass raw material from the feeding section into the storage section of the melting pot; a melting step of heating the glass raw material to melt the glass raw material; a stirring step of inserting a stirring member from the feeding port and stirring the molten glass; a fining step of degassing the molten glass after the stirring step; and a discharge step of discharging the molten glass from the discharge section to a next process after the fining step, wherein the storage section is under atmospheric pressure during the feeding step, the melting step, and the stirring step, and wherein the storage section is under reduced pressure during the fining step.

10. A method for manufacturing a glass article using the glass manufacturing apparatus according to claim 7, comprising: an introduction step of introducing the glass raw material from the introduction section into the storage section of the melting pot; a melting step of heating the glass raw material to melt the glass raw material; a stirring step of inserting a stirring member from the introduction port and stirring the molten glass; a fining step of degassing the molten glass after the stirring step; and a discharge step of discharging the molten glass from the discharge section to a next process after the fining step, wherein the first pressure reduction section and the second pressure reduction section are controlled in the fining step so that the pressure in the storage space is lower than the pressure in the storage section.

11. The method for manufacturing a glass article as described in claim 10, characterized in that the storage section is under atmospheric pressure during the feeding process, the melting process, and the stirring process, and the storage space is under reduced pressure during the feeding process, the melting process, and the stirring process.

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