Electrode, glass melting furnace, and method for producing glass article

Abstract

An electrode 4 is disposed on a bottom wall 1d or a side wall 1c of a glass melting furnace 1, in a state of being immersed in a molten glass Gm inside the glass melting furnace 1. The electrode comprises: an electrode head 5 that comes into contact with the molten glass Gm; a support body 6, one end of which is attached to the electrode head 5 and the other end of which is disposed outside the glass melting furnace 1; and a connection member 7 that connects the electrode head 5 to the support body 6. The support 6 includes: a large-diameter part 8 to which the electrode head 5 is attached via the connection member 7; and a small-diameter part 9 located closer to the outside of the glass melting furnace 1 than the large-diameter part 8. Outer diameters D1, D2 of the electrode head 5 and the large-diameter part 8 are larger than the outer diameter D3 of the small-diameter part 9.

Description

Electrode, glass melting furnace, and method for manufacturing glass article

[0001] The present invention relates to an electrode, a glass melting furnace, and a method for manufacturing a glass article.

[0002] The manufacturing process of glass articles such as glass sheets may include a melting step in which glass raw materials are heated and melted by electrodes immersed in molten glass in a glass melting furnace to produce molten glass. In this case, the electrodes are immersed in the molten glass in the glass melting furnace while being inserted into through holes provided in the bottom wall or side wall of the glass melting furnace.

[0003] As an example of an electrode, as disclosed in Patent Document 1, there can be mentioned an electrode that includes a glass melting portion (corresponding to an electrode head) made of molybdenum, a holding portion (corresponding to a support body) made of a heat-resistant alloy, and a threaded rod (corresponding to a connecting member) that connects the glass melting portion and the holding portion.

[0004] Japanese Unexamined Patent Publication No. 61-26519

[0005] Conventionally, the support is a thin rod with a fixed diameter, and the electrode head is often made small in diameter according to the diameter of the support. However, when the electrode head has a small diameter, the surface area of ​​the tip of the electrode head is small, and current concentration is likely to occur at the tip of the electrode head when current is applied. As a result, the electrode head deteriorates early due to the current concentration, and the life of the electrode is shortened.

[0006] Furthermore, if the support has a constant diameter, a special fixing mechanism must be provided separately to restrict longitudinal movement of the support, which creates the problem of making the installation work of the electrodes in the glass melting furnace complicated.

[0007] An object of the present invention is to facilitate the installation of electrodes in a glass melting furnace while extending the life of the installed electrodes.

[0008] (1) The present invention, which has been invented to solve the above-mentioned problems, provides an electrode that is placed on the bottom wall or side wall of a glass melting furnace while being immersed in molten glass inside the furnace, the electrode comprising: an electrode head that contacts the molten glass; a support having one end attached to the electrode head and the other end located outside the furnace; and a connecting member that connects the electrode head and the support, wherein the support comprises a large diameter portion to which the electrode head is attached via the connecting member, and a small diameter portion that is located closer to the furnace outside of the furnace than the large diameter portion, and the outer diameters of the electrode head and the large diameter portion are larger than the outer diameter of the small diameter portion.

[0009] In this way, the diameter of the electrode head is increased as the diameter of the large-diameter portion to which the electrode head is attached increases. This increase in the diameter of the electrode head increases the surface area of ​​the tip of the electrode head, where current concentration is likely to occur during current flow, thereby alleviating current concentration on the electrode head. As a result, wear on the electrode head due to current flow can be suppressed, and the electrode's lifespan can be extended. Furthermore, simply by supporting the bottom surface of the large-diameter portion with a refractory material or the like at a position other than the small-diameter portion, longitudinal movement of the support (movement of the support toward the outside of the furnace) can be easily restricted. This facilitates the installation of the electrode in the glass melting furnace.

[0010] (2) In the configuration of (1) above, it is preferable that the large diameter portion has a cooling mechanism that circulates a cooling liquid inside.

[0011] If the temperature around the connecting member becomes high, the connecting member may deteriorate, and the electrode head may become detached from the large diameter portion. Therefore, as in the above configuration, it is preferable to cool the area around the connecting member using a cooling mechanism provided in the large diameter portion, thereby suppressing deterioration of the connecting member.

[0012] (3) In the configuration of (2) above, it is preferable that the cooling mechanism includes a first reservoir portion that is provided closer to the connecting member and is capable of storing the cooling liquid, and a second reservoir portion that is provided closer to the outside of the glass melting furnace than the first reservoir portion and is capable of storing the cooling liquid, and that the cooling liquid can flow between the first reservoir portion and the second reservoir portion.

[0013] In this way, the cooling liquid can be stored in both the first storage section and the second storage section, so that a sufficient amount of cooling liquid can be stored in the cooling structure, thereby achieving a high cooling effect.

[0014] (4) In the configuration of (3) above, it is preferable that the first reservoir is an annular space and the second reservoir is a cylindrical space.

[0015] This creates an area inside the inner circumferential surface of the first reservoir located closer to the connecting member where the coolant is not stored. This makes it easier to ensure an appropriate distance between the first reservoir and the second reservoir, where the coolant is stored, and the connecting member. As a result, it becomes easier to adjust the temperature around the connecting member to an appropriate level.

[0016] (5) In the configuration of (3) or (4) above, the electrode is disposed on the bottom wall and includes a supply path for supplying the cooling liquid from the second storage portion to the first storage portion and a discharge path for discharging the cooling liquid from the first storage portion to the outside, and it is preferable that the height of an upper end of the discharge path within the first storage portion is higher than the height of an upper end of the supply path within the first storage portion.

[0017] In this way, if the liquid level of the coolant supplied from the supply passage into the first reservoir is lower than the height of the upper end of the discharge passage, the coolant will not be discharged outside the first reservoir. In other words, even if the supply of coolant is stopped, a predetermined amount of coolant will remain in the first reservoir, making it easier to maintain the cooling effect around the connecting member.

[0018] (6) In any of the configurations (2) to (5) above, it is preferable that the small diameter portion has a cooling structure that allows a coolant to circulate inside, and that the coolant is supplied from the small diameter portion to the large diameter portion at a position eccentric from the center of the large diameter portion toward the outer periphery.

[0019] This makes it easier to lengthen the flow path of the coolant within the large diameter portion, thereby ensuring sufficient residence time of the coolant within the large diameter portion and efficiently cooling the periphery of the connecting member.

[0020] (7) In any of the above configurations (1) to (6), it is preferable that the value obtained by dividing the outer diameter (mm) of the electrode head by the length (mm) of the electrode head is 0.8 to 1.2.

[0021] In this way, the diameter of the electrode head can be increased, thereby extending the life of the electrode.

[0022] (8) The present invention, which has been invented to solve the above problems, is a glass melting furnace, characterized by comprising an electrode having any one of the configurations (1) to (7) above.

[0023] In this way, the same effects as those of the corresponding configurations already described can be obtained.

[0024] (9) The present invention, which has been invented to solve the above-mentioned problems, is a method for manufacturing a glass article, characterized by comprising a melting step in which glass raw materials are heated and melted to produce molten glass using a glass melting furnace having the configuration of (8) above.

[0025] In this way, the same effects as those of the corresponding configurations already described can be obtained.

[0026] According to the present invention, it is possible to facilitate the installation of electrodes in a glass melting furnace and to extend the life of the installed electrodes.

[0027] Fig. 2 is a longitudinal sectional view of a glass melting furnace according to an embodiment of the present invention. Fig. 3 is a longitudinal sectional view showing an enlarged view of the periphery of an electrode in Fig. 1. Fig. 4 is a sectional view taken along the X-X line in Fig. 2. Fig. 5 is a sectional view taken along the Y-Y line in Fig. 2. Fig. 6 is a longitudinal sectional view showing an enlarged view of the periphery of a first reservoir in Fig. 1, illustrating a state in which the amount of cooling liquid in the first reservoir is small. Fig. 7 is a longitudinal sectional view showing an enlarged view of the periphery of the first reservoir in Fig. 1, illustrating a state in which the amount of cooling liquid in the first reservoir is large.

[0028] Hereinafter, an electrode, a glass melting furnace, and a method for manufacturing a glass article according to an embodiment of the present invention will be described with reference to the accompanying drawings.

[0029] As shown in Fig. 1, the apparatus for manufacturing a glass article includes a glass melting furnace 1. The manufacturing apparatus may further include, as necessary, a fining chamber for fining the molten glass produced in the glass melting furnace 1, a homogenization chamber (stirring chamber) for stirring the molten glass that has been subjected to the fining treatment, a forming device for forming a glass article from the molten glass that has been subjected to the stirring treatment, and the like.

[0030] The glass melting furnace 1 is a space for carrying out a melting process to obtain molten glass Gm. The glass melting furnace 1 continuously heats and melts glass frit Gr to form molten glass Gm. The glass frit Gr may contain cullet (recycled glass) in addition to natural raw materials and chemical raw materials.

[0031] The front wall 1a of the glass melting furnace 1 is provided with an inlet 1aa for introducing glass raw material Gr. This inlet 1aa is provided with a raw material introducing device 2. The raw material introducing device 2 may be a pusher or a vibration feeder, but is a screw feeder in this embodiment. The number and arrangement positions of the raw material introducing devices 2 can be appropriately changed depending on the size of the glass melting furnace 1, etc.

[0032] An outlet 1ba for discharging the molten glass Gm is provided on the rear wall 1b of the glass melting furnace 1. A transfer flow path 3 is connected to this outlet 1ba so that the molten glass Gm is sequentially supplied downstream. When glass articles are simultaneously produced at multiple locations, multiple outlets 1ba may be provided in the glass melting furnace 1, and the molten glass Gm may be supplied downstream via the transfer flow paths 3 connected to each outlet 1ba.

[0033] The glass melting furnace 1 has walls made of refractory bricks that define a melting space within the furnace. Examples of refractory bricks include electrocast zirconia-based bricks, electrocast alumina-based bricks, electrocast alumina-zirconia-based bricks, electrocast AZS (Al-Zr-Si)-based bricks, and dense-fired bricks.

[0034] A plurality of electrodes 4 are provided on a bottom wall 1d of the glass melting furnace 1. The electrodes 4 are immersed in the molten glass Gm and electrically heat the molten glass Gm. As a result, the glass raw material Gr is heated and melted, and the molten glass Gm is continuously produced.

[0035] Here, since the configuration of the electrode 4 is shown in a simplified bar shape in FIG. 1, the detailed structure of the electrode 4 will be described with reference to FIGS.

[0036] As shown in FIG. 2, the electrode 4 is an elongated body arranged so that its longitudinal direction is along the vertical direction, and is provided so as to penetrate the bottom wall 1d of the glass melting furnace 1 in the vertical direction.

[0037] The electrode 4 comprises an electrode head 5 that comes into contact with the molten glass Gm, a support 6 that has one end attached to the electrode head 5 and the other end positioned outside the glass melting furnace 1, and a connecting member 7 that connects the electrode head 5 and the support 6.

[0038] The support body 6 comprises a large diameter portion 8 to which the electrode head 5 is attached via a connecting member 7 , and a small diameter portion 9 located on the outer side of the glass melting furnace 1 than the large diameter portion 8 .

[0039] The lower end surface 5a of the electrode head 5 is in contact with the upper end surface 8a of the large diameter portion 8. A part of the lower end surface 8b of the large diameter portion 8 is integrated with the small diameter portion 9.

[0040] The electrode head 5 and the large-diameter portion 8 are cylindrical with a relatively large outer diameter. The small-diameter portion 9 is cylindrical with a relatively small outer diameter. That is, the outer diameter D1 of the electrode head 5 and the outer diameter D2 of the large-diameter portion 8 are larger than the outer diameter D3 of the small-diameter portion 9. In this embodiment, the outer diameter D1 of the electrode head 5 and the outer diameter D2 of the large-diameter portion 8 are the same, but they may be different. In this way, the electrode head 5 is enlarged along with the large-diameter portion 8, thereby increasing the surface area of ​​the tip (upper end) of the electrode head 5 and mitigating current concentration at the tip of the electrode head 5 during current flow. As a result, wear of the electrode head 5 due to current flow is suppressed, and the life of the electrode 4 can be extended.

[0041] The outer diameter D2 of the large diameter portion 8 is preferably 1.2 to 3 times, and more preferably 1.5 to 2 times, the outer diameter D3 of the small diameter portion 9. The value (D1 / H1) obtained by dividing the outer diameter D1 (mm) of the electrode head 5 by the length H1 (mm) of the electrode head 5 is preferably 0.8 to 1.2, for example.

[0042] The bottom wall 1d of the glass melting furnace 1 is composed of a plurality of refractory bricks 10a to 10e. The lower end surface (bottom surface) 8b of the large diameter portion 8 of the support body 6, excluding the small diameter portion 9, is supported from below by the refractory bricks 10b. In other words, the large diameter portion 8 is caught on the refractory bricks 10b, restricting downward movement of the electrode 4. Therefore, the entire electrode 4 can be easily supported, facilitating the installation of the electrode 4 in the glass melting furnace 1.

[0043] The outer peripheral surface 8c of the large diameter portion 8 and the interface between the lower end surface 5a of the electrode head 5 and the upper end surface 8a of the large diameter portion 8 are covered from the sides by refractory bricks 10a constituting the bottom wall 1d of the glass melting furnace 1. In other words, only a portion of the electrode head 5 located above the interface between the lower end surface 5a of the electrode head 5 and the upper end surface 8a of the large diameter portion 8 is in direct contact with the molten glass Gm. In this way, the refractory bricks 10a can suppress thermal deterioration of the large diameter portion 8 while suppressing the intrusion of the molten glass Gm into the interface between the electrode head 5 and the large diameter portion 8.

[0044] The small diameter portion 9 is integral with the lower end surface 8 b of the large diameter portion 8 at a position eccentric from the center of the large diameter portion 8 toward the outer periphery.

[0045] The connecting member 7 is cylindrical and has a threaded portion (male thread) 7a on its outer circumferential surface. A downwardly extending hole 11 is provided in the upper end surface 8a of the large diameter portion 8, and a threaded portion (female thread) 11a is provided in the inner circumferential surface of the hole 11 to thread with the lower part of the threaded portion 7a of the connecting member 7. An upwardly extending hole 12 is provided in the lower end surface 5a of the electrode head 5, and a threaded portion (female thread) 12a is provided in the inner circumferential surface of the hole 12 to thread with the upper part of the threaded portion 7a of the connecting member 7. In other words, in this embodiment, the support body 6 (large diameter portion 8) and the electrode head 5 are connected via the connecting member 7 by threading the threaded portions together.

[0046] The electrode head 5 is made of, for example, molybdenum. Since the electrode head 5 is immersed in the molten glass Gm, it does not come into direct contact with air. Therefore, even if the electrode head 5 is made of molybdenum, deterioration due to oxidation of molybdenum and wear due to sublimation can be suppressed.

[0047] The connecting member 7 is preferably made of molybdenum, which can prevent the connecting member 7 from being melted and damaged.

[0048] The support 6 is formed of, for example, a metal (such as steel). When the support 6 is formed of a metal, it is preferable to use low-carbon steel (for example, carbon steel with a carbon content of 0.25 mass% or less) as the metal in order to suppress hydrogen damage. Note that hydrogen damage is a phenomenon in which hydrogen that has penetrated through microcracks in the metal reacts with carbon, generating methane, which increases the internal pressure of the metal and leads to breakage.

[0049] Here, if the temperature around the connecting member 7 becomes high, the connecting member 7 may deteriorate, and the electrode head 5 may become detached from the large diameter portion 8. Specifically, if the connecting member 7 is made of molybdenum and the support 6 is made of metal, the threaded portion 7 a of the connecting member 7 may react with the support 6 due to a fining agent (As, Sb, etc.) contained in the glass raw material, and may become a low-melting-point alloy. If the surface layer of the connecting member 7 becomes a low-melting-point alloy, the threaded portion 7 a of the connecting member 7 may become easily deteriorated by heat, and the electrode head 5 may become detached from the large diameter portion 8. Therefore, in order to cool the periphery of the connecting member 7, a cooling mechanism 13 is provided inside the large diameter portion 8, and a cooling mechanism 14 is provided inside the small diameter portion 9.

[0050] The cooling mechanism 13 of the large diameter portion 8 is configured to be able to store the coolant C and includes a first storage portion 15 provided closer to the connecting member 7 and a second storage portion 16 provided on the outer side of the glass melting furnace 1 relative to the first storage portion 15. As the coolant C, for example, water is used.

[0051] The first storage section 15 and the second storage section 16 are separated into two sections, upper and lower, by a partition wall 17. The first storage section 15 is in communication with the second storage section 16 via a through-hole 17a provided in the partition wall 17 at a position eccentric to the outer periphery of the second storage section 16. The through-hole 17a functions as a supply path for supplying the coolant C from the second storage section 16 to the first storage section 15.

[0052] First reservoir 15 is configured as an annular space (see FIG. 3), and second reservoir 16 is configured as a cylindrical space (see FIG. 4). The diameter of outer peripheral surface 15a of first reservoir 15 (the outer diameter of first reservoir 15) is the same as the diameter of outer peripheral surface 16a of second reservoir 16 (the outer diameter of second reservoir 16), and the diameter of inner peripheral surface 15b of first reservoir 15 (the inner diameter of first reservoir 15) is smaller than the diameter of outer peripheral surface 16a of second reservoir 16. Note that in FIG. 3, the position of connecting member 7 projected onto the X-X cross section is virtually illustrated by a dashed dotted line.

[0053] At the vertical position where the second reservoir 16 is formed, a space for storing the coolant C is formed in the center of the large diameter portion 8. On the other hand, at the vertical position where the first reservoir 15 is formed, no space for storing the coolant C is formed in the center of the large diameter portion 8 (the region inside the inner circumferential surface 15b of the first reservoir 15). When viewed from above, the connecting member 7 is located in the region inside the inner circumferential surface 15b of the first reservoir 15. Therefore, an appropriate distance is maintained between the connecting member 7 and the first reservoir 15, and excessive cooling of the periphery of the connecting member 7 is suppressed. As a result, the cooling temperature around the connecting member 7 is appropriately adjusted.

[0054] The cooling mechanism 14 of the small diameter portion 9 includes a third storage portion 18 capable of storing the cooling liquid C. The third storage portion 18 is configured as a cylindrical space. The small diameter portion 9 and the third storage portion 18 are elongated in the vertical direction. The lower end of the small diameter portion 9 and the lower end of the third storage portion 18 are located outside the glass melting furnace 1. When viewed from above, the third storage portion 18 is located within a region inside the outer circumferential surface 16a of the second storage portion 16. The third storage portion 18 is in communication with the second storage portion 16 via a through hole 19a provided in the bottom wall 19 of the large diameter portion 8 at a position eccentric to the outer periphery of the second storage portion 16. The through hole 19a functions as a supply path for supplying the cooling liquid C from the third storage portion 18 to the second storage portion 16. Outside the glass melting furnace 1 , the cooling liquid C is supplied to the third reservoir 18 through a through hole 20 a provided in the side wall 20 of the small diameter portion 9 .

[0055] When viewed from above (in a plan view), the positions of through holes 19a formed in bottom wall 19 do not overlap in the horizontal direction with the positions of through holes 17a formed in partition wall 17. In this embodiment, when viewed from above, through holes 19a formed in bottom wall 19 are formed at positions that are circumferentially shifted by 180° from the positions of through holes 17a formed in partition wall 17. This lengthens the flow path of coolant C supplied from through holes 19a formed in bottom wall 19 into second reservoir 16 to through holes 17a formed in partition wall 17, thereby extending the residence time of coolant C in second reservoir 16 and achieving a high cooling effect with a small amount of coolant C.

[0056] First storage portion 15 is provided with discharge pipe 21 that functions as a discharge path for discharging coolant C from inside first storage portion 15 to the outside. Discharge pipe 21 is provided at a position circumferentially separated from the position of through hole 17a provided in partition wall 17. In this embodiment, when viewed from above, discharge pipe 21 is formed at a position that is circumferentially phase-shifted by 180° from the position of through hole 17a provided in partition wall 17. This lengthens the flow path of coolant C supplied from through hole 17a provided in partition wall 17 into first storage portion 15 to discharge pipe 21, thereby extending the residence time of coolant C in first storage portion 15 and achieving a high cooling effect with a small amount of coolant C.

[0057] Discharge pipe 21 extends to the outside of glass melting furnace 1 while being inserted into third storage portion 18 via partition wall 17, second storage portion 16, and through hole 19a in bottom wall 19. In the present embodiment, discharge pipe 21 extends to the outside of small diameter portion 9 via bottom wall 22 of small diameter portion 9. The outer diameter of discharge pipe 21 is smaller than the outer diameter of third storage portion 18. Therefore, even when discharge pipe 21 is inserted into third storage portion 18, coolant C can be supplied to second storage portion 16 from a portion of third storage portion 18 located outside discharge pipe 21 (a gap between third storage portion 18 and discharge pipe 21).

[0058] The upper end of the discharge pipe 21 is located higher than the partition wall 17. Therefore, the height of the upper end of the discharge pipe 21 as a discharge path is higher than the height of the upper end of the through-hole 17a of the partition wall 17 as a supply path. As a result, as shown in FIG. 5 , when the liquid level CL of the coolant C in the first storage portion 15 becomes lower than the upper end of the discharge pipe 21, the discharge of the coolant C in the first storage portion 15 to the outside is stopped. On the other hand, as shown in FIG. 6 , when the liquid level CL of the coolant C in the first storage portion 15 becomes higher than the upper end of the discharge pipe 21, the coolant C in the first storage portion 15 is discharged to the outside through the discharge pipe 21. As a result, a predetermined amount of coolant C is stored in the first storage portion 15, so that the cooling effect around the connecting member 7 can be maintained.

[0059] Next, a method for manufacturing a glass article using the manufacturing apparatus configured as above will be described.

[0060] As described above, the present manufacturing method includes a melting step, and, if necessary, further includes a fining step of subjecting the molten glass obtained in the melting step to a fining treatment, a homogenizing step of stirring the molten glass that has undergone the melting step, and a forming step of forming a glass article from the molten glass that has undergone the homogenizing step.

[0061] 1 and 2 , in the melting step, glass frit Gr is heated and melted in a glass melting furnace 1 using electrodes 4. In addition, in order to heat the glass frit Gr and / or the molten glass Gm, a burner (not shown) that forms a flame above the liquid surface of the molten glass Gm may be used in combination.

[0062] In the melting process, as shown in FIGS. 2 to 6 , the electrode 4 is cooled using cooling mechanisms 13 and 14 when current is applied to the electrode 4. Specifically, outside the glass-melting furnace 1, the coolant C is supplied through the through-hole 20 a into the third reservoir 18 of the small-diameter portion 9. The coolant C supplied into the third reservoir 18 is supplied through the through-hole 19 a into the second reservoir 16. The coolant C supplied into the second reservoir 16 is supplied through the through-hole 17 a into the first reservoir 15. When the liquid level CL of the coolant C supplied into the first reservoir 15 is higher than the upper end of the discharge pipe 21 (see FIG. 6 ), the coolant C is discharged to the outside of the glass-melting furnace 1 through the discharge pipe 21. On the other hand, when the liquid level CL of the coolant C supplied into the first reservoir 15 is lower than the upper end of the discharge pipe 21 (see FIG. 5 ), the coolant C is not discharged to the outside of the glass-melting furnace 1 through the discharge pipe 21 and remains in the first reservoir 15. By circulating the coolant C in this manner, the periphery of the connecting member 7 is cooled. The cooling temperature of the periphery of the connecting member 7 is, for example, preferably 1000° C. or less, more preferably 900° C. or less, and even more preferably 800° C. or less. The lower limit can be, for example, 700° C. or more.

[0063] Here, in the melting step, as shown in Fig. 1, a batch layer Ga as the glass frit Gr supplied into the glass melting furnace 1 and a bubble layer Gb generated by the heating and melting of the glass frit Gr may cover the surface of the molten glass Gm. The bubble layer Gb may be, for example, a layer of carbon dioxide (CO or CO ) generated by the glass frit Gr. ２ ), O ２ Gas, SO ２ 1, the surface of the molten glass Gm is covered with the batch layer Ga and the bubble layer Gb, but the batch layer Ga may be located on the bubble layer Gb covering the surface of the molten glass Gm.

[0064] Although the embodiment of the present invention has been described, the embodiment of the present invention is not limited to this, and various modifications can be made without departing from the spirit of the present invention.

[0065] In the above embodiment, the case has been described in which connecting member 7 is disposed above first storage portion 15 and the position of connecting member 7 does not overlap in the vertical direction with the position of first storage portion 15 when viewed from the side (side view), but the position of connecting member 7 may also overlap in the vertical direction with the position of first storage portion 15. In this case, at the vertical position where the first storage portion is formed, a portion of connecting member 7 is disposed in a space inside inner circumferential surface 15b of first storage portion 15.

[0066] In the above embodiment, the number and arrangement positions of the electrodes 4 can be appropriately changed depending on the size of the glass melting furnace 1, etc. For example, the electrodes 4 may be arranged on the side wall 1c instead of the bottom wall 1d. When the electrodes 4 are provided on the side wall 1c, the electrodes 4 are arranged so that their longitudinal direction is along the horizontal direction. In this case, it is preferable that the small diameter portion 9 is provided at a position eccentrically above the center of the large diameter portion 8. In this way, in the first storage portion 15, the through hole 17a functioning as a supply path is arranged at the bottom, and the discharge pipe 21 functioning as a discharge path is arranged at the top. Therefore, a predetermined amount of coolant C is stored in the first storage portion 15, making it easier to maintain the cooling effect around the connecting member 7.

[0067] In the above embodiment, the small diameter portion 9 is integrated with the large diameter portion 8 at a position eccentric from the center of the large diameter portion 8 toward the outer periphery, but this is not limiting. The small diameter portion 9 may be integrated with the large diameter portion 8 at the center of the large diameter portion 8. However, when cooling mechanisms 13, 14 that circulate coolant C through the large diameter portion 8 and the small diameter portion 9 are provided, it is preferable that the small diameter portion 9 be integrated with the large diameter portion 8 at a position eccentric from the center of the large diameter portion 8 toward the outer periphery, from the viewpoint of increasing the flow path length of the coolant C and improving the cooling effect.

[0068] In the above-described embodiments, the glass article may be, for example, a glass plate, a glass roll (a glass film wound into a roll), glass fiber, glass spheres, a glass tube, a glass block, a glass bottle, or any other shape. When the glass article is a glass plate or a glass roll, a forming method such as an overflow downdraw method, a slot downdraw method, a float method, or a redraw method is used. Note that, in order to obtain a smooth surface, it is preferable to use the overflow downdraw method as the forming method.

[0069] REFERENCE SIGNS LIST 1 glass melting furnace 1c side wall 1d bottom wall 2 raw material charging device 3 transfer flow path 4 electrode 5 electrode head 6 support 7 connecting member 8 large diameter portion 9 small diameter portion 10a to 10e firebrick 13 cooling mechanism 14 cooling mechanism 15 first storage portion 16 second storage portion 17 partition wall 17a through hole 18 third storage portion 19 bottom wall 19a through hole 20 side wall 20a through hole 21 discharge pipe C cooling liquid D1 outer diameter of electrode head D2 outer diameter of large diameter portion D3 outer diameter of small diameter portion Gm molten glass Gr glass raw material

Claims

1. An electrode arranged on a bottom wall or a side wall of a glass melting furnace while being immersed in molten glass inside the furnace, comprising: an electrode head in contact with the molten glass; a support having one end attached to the electrode head and the other end arranged outside the furnace; and a connecting member connecting the electrode head and the support, wherein the support has a large diameter portion to which the electrode head is attached via the connecting member, and a small diameter portion located closer to the outside of the furnace than the large diameter portion, and the outer diameters of the electrode head and the large diameter portion are larger than the outer diameter of the small diameter portion.

2. The electrode according to claim 1, wherein the large diameter portion has a cooling mechanism for circulating a cooling liquid therein.

3. The electrode described in claim 2, wherein the cooling mechanism comprises a first storage section disposed closer to the connecting member and capable of storing the cooling liquid, and a second storage section disposed closer to the outside of the glass melting furnace than the first storage section and capable of storing the cooling liquid, and the cooling liquid can flow between the first storage section and the second storage section.

4. The electrode of claim 3, wherein said first reservoir is a toroidal space and said second reservoir is a cylindrical space.

5. The electrode according to claim 3 or 4, wherein the electrode is disposed on the bottom wall and comprises a supply path for supplying the cooling liquid from the second storage portion to the first storage portion and a discharge path for discharging the cooling liquid from the first storage portion to the outside, and the height of an upper end of the discharge path within the first storage portion is higher than the height of an upper end of the supply path within the first storage portion.

6. An electrode as described in claim 2 or 3, wherein the small diameter portion has a cooling structure that circulates a coolant therein, and the coolant is supplied from the small diameter portion to the large diameter portion at a position eccentric from the center of the large diameter portion toward the outer periphery.

7. The electrode according to claim 1 or 2, wherein the value obtained by dividing the outer diameter (mm) of the electrode head by the length (mm) of the electrode head is 0.8 to 1.

2.

8. A glass melting furnace equipped with the electrode according to claim 1 or 2.

9. A method for manufacturing a glass article, comprising a melting step of heating and melting glass raw materials to produce molten glass using the glass melting furnace according to claim 8.

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