Method for manufacturing glass articles

Abstract

To appropriately prevent the damage of a transfer pipe and the solidification of molten glass from progressing when generating a trouble in current supply from power supply equipment used for the electric heating of molten glass in a melting furnace and the electric heating of a transfer pipe.SOLUTION: A method for manufacturing a glass article comprises: the melting step S1 of electrically heating molten glass Gm in a melting furnace 2 using an electrode Px by a current supplied from operation power supply equipment 15; the transfer step S2 of electrically heating a transfer pipe P included in a transfer device 3 by the current supplied from the operation power supply equipment 15; the molding step S3 of molding a glass article from the molten glass Gm transferred by the transfer device 3 using a molding apparatus 4; and the treatment step S4 of performing continuous transfer treatment for continuously transferring the molten glass Gm to at least the middle of the transfer device 3 from the melting furnace 2 when generating a trouble in the current supply from the operation power supply equipment 15.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a method for producing a glass article from molten glass produced in a melting furnace and transported through a transfer pipe. [Background technology]

[0002] As is well known, when producing glass articles such as glass sheets and glass tubes, molten glass is transferred from a melting furnace to a forming device. The path along which the molten glass is transferred is formed by a plurality of transfer pipes. When producing molten glass in the melting furnace or transferring the molten glass in each transfer pipe, a power supply facility is generally used to supply current to the melting furnace and each transfer pipe.

[0003] More specifically, Patent Document 1 discloses that a plurality of electrodes projecting toward the inside of a melting furnace are disposed on the bottom wall of the furnace, and that the molten glass in the furnace is heated by passing electricity through these electrodes. Patent Document 2 discloses that the molten glass in a transfer pipe is heated by passing electricity through the transfer pipe using electrodes formed on the flange of the transfer pipe.

[0004] The electrical heating of the molten glass in the melting furnace disclosed in Patent Document 1 and the electrical heating of the transfer pipe disclosed in Patent Document 2 are both performed by supplying current from a power supply facility. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2018-193269 [Patent Document 2] Japanese Patent Application Laid-Open No. 2015-105196 Summary of the Invention [Problem to be solved by the invention]

[0006] Meanwhile, while a glass article is being produced in a forming apparatus from molten glass that has been transferred while undergoing the above-mentioned two types of electrical heating, a sudden disruption in the supply of current from some or all of the equipment in the power supply equipment may occur. Specifically, a situation may arise in which the equipment (some or all of the equipment) is unable to supply current due to a power outage, or the equipment is unable to supply current normally due to a malfunction or the like.

[0007] When this happens, the temperature of the molten glass in the melting furnace and the transfer pipe drops. The temperature drop in the transfer pipe is particularly significant, making the transfer pipe susceptible to damage such as undue deformation and rupture. This problem is exacerbated by the large difference in the degree of shrinkage between the transfer pipe and the supporting bricks (refractory bricks) surrounding it.

[0008] Furthermore, since the molten glass continues to solidify in the melting furnace and the transfer pipe, when the supply of current from the equipment is restored, troublesome and complicated repair work must be carried out on the melting furnace and the transfer pipe in order to restore the ability to transfer molten glass.

[0009] From the above viewpoints, an object of the present invention is to appropriately prevent damage to the transfer pipe and the progress of solidification of the molten glass when a problem occurs in the supply of current from a power supply equipment used for electrically heating the molten glass in the melting furnace and for electrically heating the transfer pipe. [Means for solving the problem]

[0010] The present invention, which was invented to solve the above-mentioned problems, is a method for manufacturing glass articles, comprising: a melting step in which molten glass is produced from glass raw materials in a melting furnace by electrically heating the molten glass using electrodes with an electric current supplied from an operating power supply equipment; a transfer step in which molten glass flowing out of the melting furnace is transferred through a transfer pipe provided in a transfer device while being electrically heated with an electric current supplied from the operating power supply equipment; and a forming step in which a glass article is formed from the molten glass transferred by the transfer device using a forming device, the method further comprising a response step in the event of a disruption in the supply of electric current from the operating power supply equipment, wherein the response step is characterized by performing a continuous transfer process to continue transferring molten glass from the melting furnace to at least halfway through the transfer device.

[0011] According to this configuration, if a failure occurs in the supply of current from the operating power supply equipment (all or part of the power supply equipment), a transfer continuation process is performed in the response process, allowing molten glass to continue being transferred from the melting furnace to at least partway through the transfer device. The heat of the molten glass being continuously transferred reduces the temperature drop in the transfer pipe located at least in the upstream portion of the transfer device. As a result, damage such as rupture of the transfer pipe can be appropriately prevented. Furthermore, the continued transfer of molten glass allows the molten glass to continue flowing in the melting furnace, appropriately stopping the solidification of the molten glass not only in the transfer pipe but also in the melting furnace. As a result, once the supply of current from the operating power supply equipment is restored, the melting furnace and at least the upstream portions of the transfer device can resume transferring molten glass with only simple or no repair work.

[0012] In this configuration, a standby power supply equipment is provided that can be used in the event of a disruption in the supply of current from the operating power supply equipment, and in the response process, current may be supplied from the standby power supply equipment to the electrodes of the melting furnace and / or the transfer pipe as the transfer continuation process.

[0013] In this way, the standby power supply equipment is effectively utilized to continue the transfer process. In this case, the standby power supply equipment supplies current to the electrodes of the melting furnace, the transfer pipe, or both, and in either case, the temperature drop of the molten glass being transferred can be reduced. This is advantageous for continuing the transfer of molten glass.

[0014] In the above configuration, the melting furnace may be equipped with a burner heating means capable of producing molten glass in the melting furnace by combustion heating using a burner, and in the melting process, molten glass may be produced only by electrical heating using the electrodes, and in the treatment process, molten glass may be produced by the burner heating means as the transfer continuation process.

[0015] In this way, the burner heating means is effectively used to perform the continuous transfer process. In this case, the burner heating means performs the heating necessary to produce molten glass, so that the temperature drop of the molten glass being transferred can be more reliably reduced.

[0016] Alternatively, the melting furnace may be provided with a burner heating means that contributes to the production of molten glass in the melting furnace by combustion heating using a burner, and in the melting process, molten glass is produced by electrical heating using the electrodes and combustion heating using the burner heating means, and in the countermeasure process, as the transfer continuation process, the heat generation amount of the burner heating means may be increased to be greater than the heat generation amount of the burner heating means in the melting process.

[0017] In this way, the amount of heat generated by the burner heating means is increased to compensate for the decrease in the amount of heat generated by the electrical heating using the electrodes, and the burner heating means is effectively used to perform the transfer continuation process, thereby more reliably reducing the temperature decrease of the molten glass being transferred.

[0018] In the above-described configuration, the transfer device may include a fining tank, a stirring tank, and a condition adjusting tank, which are constituted by the transfer pipe, and in the treatment step, the molten glass may be discharged from an outlet provided at the bottom of the stirring tank as the transfer continuation treatment.

[0019] In this way, discharging the molten glass from the outlet of the stirred tank promotes the transfer of the molten glass from the melting furnace to the stirred tank, enabling continuous transfer of the molten glass. This reduces the temperature drop of the molten glass in the stirred tank and in the upstream portion of the transfer device. Therefore, this configuration prevents damage to the stirred tank and the refining tank located upstream of it.

[0020] In the above-described configuration, the coping step may include continuously transferring the molten glass to the forming device by the transfer device, thereby continuously supplying the molten glass to the forming device.

[0021] In this way, by performing a transfer continuation process such as supplying current from the aforementioned standby power supply equipment and / or heating by a burner heating means, it becomes possible to continuously transfer molten glass from the upstream end to the downstream end of the transfer device. The molten glass continuously transferred to the downstream end of the transfer device is then continuously supplied to the forming device. In this case, the forming device may be damaged by an extreme drop in temperature, but if molten glass is continuously supplied to the forming device, the temperature drop is significantly reduced due to the heat of the molten glass supplied. Therefore, this configuration can prevent damage to all of the transfer pipes of the transfer device and the forming device (especially the forming body).

[0022] In the above configuration, when the transfer continuation process is performed in the countermeasure step, the flow rate of the molten glass transferred by the transfer device may be made smaller than the flow rate of the molten glass transferred by the transfer device in the transfer step.

[0023] This makes it possible to reduce the capacity of the standby power supply equipment and the heat generation amount of the burner heating means, thereby preventing an increase in equipment costs and an increase in the complexity of the equipment. [Effects of the Invention]

[0024] According to the present invention, when a problem occurs in the supply of current from the power supply equipment used for electrically heating the molten glass in the melting furnace and the transfer pipe, damage to the transfer pipe and the progress of solidification of the molten glass can be appropriately prevented. [Brief explanation of the drawings]

[0025] [Figure 1] 1 is a schematic side view showing the basic configuration of a manufacturing apparatus for carrying out a glass article manufacturing method according to an embodiment of the present invention. [Figure 2] FIG. 2 is a perspective view showing a lateral portion of a transfer pipe, which is a component of a manufacturing apparatus for carrying out a manufacturing method for a glass article according to an embodiment of the present invention. [Figure 3] FIG. 2 is a perspective view showing a vertical transfer pipe, which is a component of a manufacturing apparatus for carrying out a glass article manufacturing method according to an embodiment of the present invention. [Figure 4] 1 is a process diagram showing various steps of a method for manufacturing a glass article according to an embodiment of the present invention. FIG. [Figure 5] 1 is a schematic side view showing a state in which a first example of a transfer continuation process is being performed in a handling step in a glass article manufacturing method according to an embodiment of the present invention. FIG. [Figure 6] A schematic side view showing a state in which a second or third example of a transfer continuation process is being performed in the handling step in a glass article manufacturing method according to an embodiment of the present invention. [Figure 7] A schematic side view showing a state in which a fourth example of a transfer continuation process is being performed in the handling step in the glass article manufacturing method according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0026] Hereinafter, a method for manufacturing a glass article according to an embodiment of the present invention will be described with reference to the accompanying drawings.

[0027] Fig. 1 illustrates the basic configuration of a manufacturing apparatus for carrying out a method for manufacturing a glass article according to the present invention. As shown in the figure, the manufacturing apparatus 1 roughly includes a melting furnace 2 disposed at the upstream end and for heating glass raw materials to produce molten glass Gm, a transfer device 3 for transferring the molten glass Gm flowing out of the melting furnace 2 downstream, and a forming device 4 for forming a glass ribbon Gr using the molten glass Gm supplied from the transfer device 3.

[0028] The melting furnace 2 defines a melting space therein by walls made of firebricks or the like. A plurality of electrodes Px are disposed on the bottom wall 2a of the melting furnace 2, protruding into the furnace and immersed in the molten glass Gm. These electrodes Px heat the molten glass Gm by passing electricity through them. In this case, the molten glass Gm in the melting furnace 2 may be heated only by passing electricity through the electrodes Px, or in addition, a burner heating means 17, which will be described later, may be used. The melting furnace 2 is provided with a raw material feeder (e.g., a screw feeder) that feeds glass raw materials onto the molten glass Gm from outside the furnace.

[0029] Transfer device 3 comprises, as its main components, a fining tank 5, a stirring tank 6, and a condition adjusting tank 7, in that order from the upstream side. An inlet 5a of fining tank 5 is connected to an outlet 2b of melting furnace 2 via an upstream connecting pipe 8. An outlet 5b of fining tank 5 is connected to an inlet 6a of stirring tank 6 via a midstream connecting pipe 9. An outlet 6b of stirring tank 6 is connected to an inlet 7a of condition adjusting tank 7 via a cooling pipe 10. The upstream connecting pipe 8, midstream connecting pipe 9, and cooling pipe 10 are also components of transfer device 3.

[0030] The fining tank 5 is used to perform a fining treatment on the molten glass Gm produced in the melting furnace 2. The stirring tank 6 is used to perform a homogenization treatment on the molten glass Gm that has been subjected to the fining treatment by stirring it with stirring blades (stirrers) 6x. The cooling pipe 10 is used to cool the molten glass Gm that has been subjected to the homogenization treatment and adjust its viscosity and other properties. The condition adjusting tank 7 is used to further adjust the viscosity, flow rate, and other properties of the cooled molten glass Gm. Note that a plurality of stirring tanks 6 may be arranged on the transfer path of the transfer device 3.

[0031] The refining vessel 5, the upstream connecting pipe 8, the midstream connecting pipe 9, and the cooling pipe 10 are all constituted by a transfer pipe P, and more specifically, by a horizontal transfer pipe P1 as shown in FIG. 2. The horizontal transfer pipe P1 has a pipe axis Z extending along the horizontal direction. Here, when the horizontal transfer pipe P1 constitutes the refining vessel 5 and the midstream connecting pipe 9, its pipe axis Z extends along the horizontal direction (including a slightly inclined direction). When the horizontal transfer pipe P1 constitutes the upstream connecting pipe 8 and the cooling pipe 10, its pipe axis Z extends along an inclined direction that gradually rises as it moves downstream. The horizontal transfer pipe P1 includes a tubular portion Pa through which the molten glass Gm flows, flange portions Pb provided at one and the other ends of the tubular portion Pa in the pipe axis Z direction, and electrodes Py attached to the outer peripheries of the flange portions Pb. These electrodes Py electrically heat the horizontal transfer pipe P1, and the molten glass Gm in the horizontal transfer pipe P1 is heated by this electrical heating. Note that the refining vat 5, the upstream connecting pipe 8, the midstream connecting pipe 9, and the cooling pipe 10 may each be configured by connecting a plurality of horizontal transfer pipes P1.

[0032] The tubular portion Pa can be made of platinum, a platinum alloy (e.g., a platinum-rhodium alloy), reinforced platinum, or a reinforced platinum alloy. The flange portions Pb and the electrodes Py can be made of platinum, a platinum alloy, reinforced platinum, a reinforced platinum alloy, nickel, or a nickel alloy. The flange portions Pb are fixed to one end and the other end of the tubular portion Pa in the tube axis Z direction by welding or the like. The materials of each portion and the method of fixing the flange portions Pb to the tubular portion Pa described here also apply to the vertical transfer pipe P2 described below.

[0033] The stirring tank 6 is composed of a transfer pipe P, specifically, a vertical transfer pipe P2 as shown in FIG. 3. The vertical transfer pipe P2 is fundamentally different from the horizontal transfer pipe P1 in that its pipe axis Z is aligned vertically (preferably vertically) and that electrodes Py are attached to the outer peripheries of flange portions Pb provided at the upper and lower ends of the tubular portion Pa. The upper flange portion Pb has an opening corresponding to the inner circumferential surface of the tubular portion Pa, similar to the flange portion Pb of the horizontal transfer pipe P1 described above. However, the lower flange portion Pb is a blind flange without such an opening. The lower flange portion Pb also has a drain port (see FIG. 7 described later) for discharging the molten glass. Furthermore, the upper and lower peripheral walls of the tubular portion Pa of the vertical transfer pipe P2 are respectively formed with the inlet 6a and outlet 6b described above. An inlet pipe 9a communicating with a midstream connecting pipe 9 is connected to the inlet 6a, and an outlet pipe 10a communicating with a cooling pipe 10 is connected to the outlet 6b. The opening at the upper end of the vertical transfer pipe P2 is covered with a lid (not shown), and the rotation shaft of the stirring blade 6x is inserted into a through-hole provided in the center of the lid. The condition adjustment tank 7 is composed of a transfer pipe P, and although there are differences in shape and the like from the vertical transfer pipe P2 shown in the illustration, a similar configuration can be adopted.

[0034] 1, the forming apparatus 4 has a forming body 11 in which molten glass Gm is caused to flow down and formed into a ribbon shape by the overflow downdraw method, and a large-diameter introduction pipe 12 that introduces the molten glass Gm to the forming body 11. The molten glass Gm is supplied to the introduction pipe 12 via the condition adjustment tank 7 of the transfer apparatus 3 and a small-diameter pipe 13 that is a component thereof. Therefore, in this embodiment, the downstream end of the transfer apparatus 3 is the outlet 13b of the small-diameter pipe 13 in the condition adjustment tank 7. The upstream end of the transfer apparatus 3 is the inlet 8a of the upstream connecting pipe 8 described above. Note that, although the introduction pipe 12 is a component of the forming apparatus 4 in this embodiment, it may also be a component of the transfer apparatus 3.

[0035] The glass ribbon Gr formed into a band shape is supplied to an annealing process and a cutting process, where plate glass of the desired dimensions is cut out as a glass article. The plate glass obtained here has a thickness of, for example, 0.01 to 2 mm and is used as a glass substrate or cover glass for displays such as liquid crystal displays and organic EL displays. Note that the forming device 4 may be one that implements other downdraw methods such as the slot downdraw method, or one that implements a method other than the downdraw method, such as the float method.

[0036] As the glass for the plate glass, silicate glass or silica glass is used, preferably borosilicate glass, soda-lime glass, aluminosilicate glass, or chemically strengthened glass is used, and most preferably alkali-free glass is used. Here, alkali-free glass refers to glass that is substantially free of alkali components (alkali metal oxides), specifically glass with a weight ratio of alkali components of 3000 ppm or less. In this embodiment, 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.

[0037] In addition to the above configuration, the manufacturing apparatus 1 is equipped with an operating power supply facility 15, as shown in Fig. 1. This operating power supply facility 15 supplies current to the electrodes Px of the melting furnace 2 and the electrodes Py of the transfer pipe P (electrodes of the horizontal transfer pipe P1 and the vertical transfer pipe P2). In this case, the operating power supply facility 15 may be a single facility or may consist of multiple facilities (details will be described later).

[0038] Next, a method for manufacturing a glass article according to an embodiment of the present invention will be described in detail.

[0039] As shown in FIG. 4, this manufacturing method includes a melting step S1, a transferring step S2, a molding step S3, and a treating step S4.

[0040] The melting step S1 is a step of producing molten glass Gm from glass raw materials in the melting furnace 2 by electrically heating the molten glass Gm using electrodes Px with an electric current supplied from the operating power supply equipment 15.

[0041] The transfer process S2 is a process in which the molten glass Gm flowing out from the outlet 2b of the melting furnace 2 is transferred through each transfer pipe P of the transfer device 3 while the transfer pipe P is electrically heated using an electrode Py with current supplied from the operating power supply equipment 15.

[0042] The forming step S3 is a step of forming a glass article using a forming device 4 from the molten glass Gm transferred by each transfer pipe P of the transfer device 3.

[0043] The countermeasure step S4 is a step for dealing with a problem in the supply of current from the operating power supply equipment 15. In this countermeasure step S4, a transfer continuation process is performed to continue transferring the molten glass Gm from the melting furnace 2 to at least partway to the transfer device 3. Note that a problem in the supply of current occurs when a power outage occurs or when the operating power supply equipment 15 breaks down, etc., if the operating power supply equipment 15 receives power from an electric power company. Furthermore, if the operating power supply equipment 15 generates power privately, this means a problem in the operation of the operating power supply equipment 15 breaking down, etc. Furthermore, if the operating power supply equipment 15 includes equipment that receives power from an electric power company and equipment that generates power privately, this means a problem in the operation of either or both of these equipment that receives power from an electric power company and that generates power privately, this means a problem in the operation of the operating power supply equipment 15 ...

[0044] The advantages of performing the transfer continuation process in the countermeasure step S4 are as follows. That is, when a disruption in the supply of electric current occurs as described above, the molten glass Gm continues to be transferred at least partway through the transfer device 3, and the heat of this continuously transferred molten glass Gm reduces the temperature drop in the transfer pipe P located at least in the upstream portion of the transfer device 3. As a result, damage such as rupture of the transfer pipe P of the transfer device 3 can be appropriately prevented. Furthermore, the continued transfer of the molten glass Gm causes the molten glass Gm to continue flowing in the melting furnace 2, and the progress of solidification of the molten glass Gm not only in the transfer pipe P but also in the melting furnace 2 can be appropriately stopped. As a result, when the supply of electric current from the operating power supply equipment 15 is restored, the transfer of molten glass Gm can be restored with only simple repair work or no repair work on the transfer pipe P or the melting furnace 2.

[0045] Hereinafter, first to fourth examples of the transfer continuation process performed in the handling step S4 will be described.

[0046] FIG. 5 is a schematic side view illustrating a first example of the transfer continuation process. As shown in the figure, the first example includes a standby power supply 16 that can be used in the event of a disruption in the supply of current from the operating power supply 15. With this basic configuration, in the countermeasure step S4, current is supplied from the standby power supply 16 to the electrodes Px of the melting furnace 2 and the electrodes Py of each transfer pipe P of the transfer device 3. In this manner, the supply of current from the standby power supply 16 enables the continuous transfer of the molten glass Gm. In this first example, the molten glass Gm can be continuously transferred to the downstream end of the transfer device 3 (in this embodiment, the outlet 13b of the condition adjustment tank 7). In this manner, the molten glass Gm flowing out from the downstream end 13b of the transfer device 3 is continuously supplied to the forming body 11 through the introduction pipe 12 of the forming device 4. Therefore, in this first example, the temperature drop of the molten glass Gm in all of the transfer pipes P and introduction pipes 12 of the transfer device 3, and ultimately the molten glass Gm supplied to the forming body 11, can be reduced. As a result, not only can damage to all of the transfer pipes P and the introduction pipe 12 of the transfer device 3 be prevented, but also damage to the formed bodies 11 can be prevented. Specifically, the formed bodies 11 can be damaged, such as cracks, if a sudden drop in temperature occurs when the supply of molten glass Gm is stopped or a sudden rise in temperature occurs when the supply of molten glass Gm is resumed. However, such problems do not occur when the molten glass Gm is continuously supplied. When this first example is performed, the flow rate A of the transferred molten glass Gm is set to be less than the flow rate B of the molten glass Gm transferred during the transfer step S2. Preferably, the flow rate A is 30 to 99%, more preferably 30 to 90%, of the flow rate B. However, the flow rate A may be equal to the flow rate B. This reduces the capacity of the standby power supply equipment 16, thereby preventing increases in equipment costs and complexity. Furthermore, in this first example, the operating power supply equipment 15 receives power from a power company and the standby power supply equipment 16 is a privately generated power source, but the reverse may also be true. Alternatively, the operating power supply equipment 15 may be a combination of power supplied from an electric power company and power generated by a private generator, and the backup power supply equipment 16 may be powered by another private generator (one or more private generators).Furthermore, in this first example, the capacity (capacity) of the standby power supply equipment 16 is smaller than the capacity of the operating power supply equipment 15 (for example, 20% to 99%, more preferably 20% to 90%), but the capacity may be the same or the capacity may be the same.

[0047] FIG. 6 is a schematic side view illustrating a second example of the transfer continuation process. As shown in the figure, in this second example, the melting furnace 2 is equipped with a burner heating means 17 capable of producing molten glass Gm, and in the melting step S1, the molten glass Gm is produced solely by electrical heating using the electrodes Px of the melting furnace 2. With this basic configuration, in the treatment step S4, the molten glass Gm is produced in the melting furnace 2 by the burner heating means 17. In this manner, the burner heating means 17 provides the heating necessary to produce the molten glass Gm, thereby more reliably reducing the temperature drop of the molten glass Gm being continuously transferred. In this second example, the molten glass can be continuously transferred up to the upstream or downstream portion of the transfer device 3, thereby reducing the temperature drop of the molten glass Gm in the transfer pipe P in that portion of the transfer device 3. Therefore, in this second example, damage to the transfer pipe P in that portion of the transfer device 3 can be prevented. Since the flow rate of the molten glass Gm transferred when this second example is performed is the same as that in the first example described above, the amount of heat generated by the burner heating means 17 can be reduced, thereby preventing an increase in equipment costs, etc. This second example may be used in combination with the first example described above. That is, in the countermeasure step S4, current may be supplied from the standby power supply equipment 16 to the electrodes Py of each transfer pipe P, or alternatively or in addition, current may be supplied from the standby power supply equipment 16 to the electrodes Px of the melting furnace 2.

[0048] The burner heating means 17 can be configured, for example, by a plurality of burners arranged on the side wall of the melting furnace 2, and each burner heats the glass raw material and the molten glass Gm by spraying a flame above the molten glass in the melting furnace 2. In the melting step S1, the burners may be removed, and in the treating step S4, the burners may be attached.

[0049] A third example of the transfer continuation process will be described with reference to the same figure. In the third example, in the melting step S1, molten glass Gm is generated by electrical heating using the electrodes Px of the melting furnace 2 and heating using the burner heating means 17, which contributes to the generation of molten glass Gm in the melting step S1. Under this basic configuration, in the countermeasure step S4, the heat generation amount of the burner heating means 17 is increased relative to the heat generation amount of the burner heating means 17 in the melting step S1. In this way, the reduction in the amount of heat generated by electrical heating using the electrodes Px is compensated for by the increase in the heat generation amount of the burner heating means 17, and molten glass Gm is generated by the burner heating means 17. Therefore, in this third example, the temperature drop of the transferred molten glass Gm can be more reliably reduced, and the molten glass Gm can be more appropriately continued to be transferred to the upstream or downstream portion of the transfer device 3. Furthermore, the flow rate of the molten glass Gm transferred when this third example is performed is the same as in the first example. Therefore, this third example achieves the same effects as the second example. This third example may be used in combination with the first example described above. That is, in the countermeasure step S4, current may be supplied from the standby power supply equipment 16 to the electrodes Py of each transfer pipe P, or alternatively or in addition, current may be supplied from the standby power supply equipment 16 to the electrodes Px of the melting furnace 2.

[0050] The increase in the heat output of the burner heating means 17 may be achieved, for example, by increasing the heat output per burner, by increasing the number of operating burners, or by a combination of these.

[0051] FIG. 7 is a schematic side view illustrating a fourth example of the transfer continuation process. As shown in FIG. 7, in the fourth example, in the countermeasure step S4, molten glass Gm is discharged from the drain port 6e of the stirred tank 6. In this case, the timing for starting the discharge of molten glass Gm from the drain port 6e can be, for example, when the supply of molten glass Gm to the forming device 4 stops. In this manner, the discharge of molten glass Gm from the drain port 6e of the stirred tank 6 promotes the transfer of molten glass Gm from the melting furnace 2 to the stirred tank 6, thereby enabling continuous transfer of molten glass Gm. This reduces the temperature drop of molten glass Gm in the stirred tank 6 and in the transfer pipe P upstream of it in the transfer device 3. Therefore, this fourth example prevents damage to the stirred tank 6, midstream connecting pipe 9, fining tank 5, and upstream connecting pipe 8. The flow rate (flow rate per unit length) of molten glass Gm transferred when this fourth example is performed is the same as in the first example described above. In addition, instead of the configuration here, a drain port may be formed in a location other than the stirring tank 6 in the transfer device 3, and the molten glass Gm may be discharged from the drain port. In addition, this fourth example may be used in combination with the above-mentioned first example, or may be used in combination with either the second example or the third example, or may be used in combination with the first example and the second example, or may be used in combination with the first example and the third example.

[0052] The method for manufacturing a glass article according to an embodiment of the present invention has been described above, but the present invention is not limited to this, and various variations are possible without departing from the gist of the present invention.

[0053] For example, in the above embodiment, the present invention is applied to a method for manufacturing a glass sheet, but the present invention may also be applied to a method for manufacturing a glass product other than a glass sheet (for example, a glass roll, a glass tube, a glass fiber, etc.).

[0054] In the above embodiments, the first to fourth examples have been given as examples of the continuous transfer process for continuously transferring molten glass in the transfer pipe. However, other processes may be performed or used in combination as long as they allow the molten glass to be continuously transferred in the transfer pipe when a problem occurs in the supply of electric current. For example, in the countermeasure step S4, it is preferable to supply glass frits onto the molten glass Gm from outside the furnace. The supply of glass frits may be performed intermittently or continuously. Furthermore, a raw material supplying machine may be used to supply the glass frits, or the glass frits may be added manually. When a raw material supplying machine is used in the countermeasure step S4, it is preferable to supply electric current to the raw material supplying machine from a standby power supply facility 16. [Explanation of symbols]

[0055] 1 Manufacturing equipment 2. Melting furnace 3 Transfer device 4 Molding equipment 5. Clarifying tank 6 Stirring tank 6d Bottom of the mixing vessel (bottom wall) 6e Drain port of mixing tank 7 Conditioning tank 8 Upstream connecting pipe 8a Upstream end of transfer pipe (inlet of upstream pipe) 9. Midstream connecting pipe 10 Cooling pipe 11. Components of molding device (molded body) 13 Small diameter pipe in conditioning tank 13b Downstream end of transfer pipe (outlet of conditioning tank) 15. Power supply equipment for operation 16 Standby power supply equipment 17 Burner heating means Gm molten glass P transfer pipe P1 Lateral transfer pipe P2 vertical transfer pipe Pa tubular part Pb flange Px melting furnace electrodes Py Transfer tube electrode S1 Melting process S2 Transfer Project S3 Molding Engineering S4 Department Project

Claims

1. a melting step of producing molten glass from glass raw materials by electrically heating the molten glass using electrodes in a melting furnace with an electric current supplied from an operating power supply equipment; a transfer step of transferring the molten glass flowing out of the melting furnace through a transfer pipe provided in a transfer device while electrically heating the transfer pipe with an electric current supplied from the operating power supply equipment; a forming step of forming a glass article using a forming device from the molten glass transferred by the transfer device, further comprising a step of dealing with a problem when a problem occurs in the supply of current from the operating power supply equipment; In the countermeasure step, a transfer continuation process is performed to continuously transfer the molten glass from the melting furnace to at least partway through the transfer device, A method for manufacturing a glass article, characterized in that when the transfer continuation process is performed in the handling step, the flow rate of molten glass transferred by the transfer device is made less than the flow rate of molten glass transferred by the transfer device in the transfer step.

2. a standby power supply facility that can be used in the event of a failure in the supply of current from the operating power supply facility; The method for manufacturing a glass article according to claim 1 , wherein the countermeasure step comprises supplying current from the standby power supply equipment to the electrodes of the melting furnace and / or the transfer pipe as the transfer continuation process.

3. the melting furnace includes a burner heating means capable of generating molten glass in the melting furnace by combustion heating using a burner, In the melting step, molten glass is generated only by electrical heating using the electrodes, The method for manufacturing a glass article according to claim 1 or 2, wherein the treatment step includes producing molten glass by the burner heating means as the transfer continuation process.

4. the melting furnace is provided with burner heating means that contributes to the production of molten glass in the melting furnace by combustion heating using a burner, In the melting step, molten glass is generated by electrical heating using the electrodes and combustion heating using the burner heating means, 3. The method for manufacturing a glass article according to claim 1, wherein in the countermeasure step, the heat generation amount of the burner heating means is increased as the transfer continuation process to be greater than the heat generation amount of the burner heating means in the melting step.

5. the transfer device includes a fining tank, a stirring tank, and a conditioning tank configured by the transfer pipe, 5. The method for manufacturing a glass article according to claim 1, wherein in the handling step, the molten glass is discharged from a discharge port provided at a bottom of the stirring tank as the transfer continuation process.

6. The method for manufacturing a glass article according to any one of claims 1 to 4, wherein in the handling step, the molten glass is continuously transferred to the forming device by the transfer device, thereby continuing the supply of molten glass to the forming device.

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