JP7808258B2 - Method for manufacturing glass articles - Google Patents

Description

The present invention relates to a method for producing glass articles from molten glass produced in a melting furnace and transported through a transfer pipe.

As is well known, when manufacturing 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 multiple transfer pipes. When producing molten glass in the melting furnace and transferring the molten glass within each transfer pipe, power supply equipment is generally used to supply current to the melting furnace and each transfer pipe.

More specifically, Patent Document 1 discloses arranging multiple electrodes protruding into the bottom wall of a melting furnace, and using these electrodes to electrically heat the molten glass in the furnace. Furthermore, Patent Document 2 discloses heating the molten glass in a transfer pipe by electrically heating the transfer pipe using electrodes formed on the flange of the transfer pipe.

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

Japanese Patent Application Laid-Open No. 2018-193269 JP 2015-105196 A

However, while glass articles are being produced in a molding device from molten glass that has been transported while undergoing the two types of electrical heating described above, there may be a sudden disruption in the supply of current from some or all of the equipment in the power supply system. Specifically, a power outage may occur that prevents the equipment (some or all of the equipment described above) from supplying current, or the equipment may malfunction and be unable to supply current normally.

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

Furthermore, because the molten glass continues to solidify inside the melting furnace and transfer pipe, once the supply of electricity from the equipment is restored, tedious and complicated repair work must be carried out on the melting furnace and transfer pipe to restore the ability to transfer molten glass.

In light of the above, the objective of the present invention is to appropriately prevent damage to the transfer pipe and the progression of solidification of the molten glass in the event of a disruption 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.

The present invention, which was devised to solve the above 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 current supplied from an operating power supply; 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 current supplied from the operating power supply; 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 comprises a response step in the event of a disruption in the supply of current from the operating power supply equipment, wherein the response step comprises a continuous transfer process to continue transferring molten glass from the melting furnace to at least partway through the transfer device.

With this configuration, if a disruption occurs in the supply of current from the operating power supply equipment (all or part of the power supply equipment), a continuous transfer 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 this continuously transferred molten glass 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 keeps the molten glass flowing within the melting furnace, appropriately stopping the solidification of the molten glass not only within the transfer pipe but also within the melting furnace. As a result, once the supply of current from the operating power supply equipment is restored, molten glass can be transferred as usual with only simple or no repair work required for the melting furnace or at least the upstream portion of the transfer device.

In this configuration, a backup power supply can be provided that can be used in the event of a disruption in the supply of current from the operating power supply, and in the response process, current can be supplied from the backup power supply to the electrodes of the melting furnace and/or the transfer pipe as part of the transfer continuation process.

In this way, the standby power supply equipment can be effectively used 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 either method can reduce the temperature drop of the molten glass being transferred. This is advantageous for continuing the transfer of molten glass.

In the above configuration, the melting furnace may be equipped with a burner heating means capable of producing molten glass within the melting furnace by combustion heating using a burner, and in the melting process, molten glass may be produced solely 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.

In this way, the burner heating means is effectively used to continue the transfer process. In this case, the burner heating means provides the heating necessary to produce molten glass, more reliably reducing the temperature drop of the molten glass being transferred.

Alternatively, the melting furnace may be equipped with a burner heating means that contributes to the production of molten glass within 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, 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 as the transfer continuation process.

In this way, the loss in the amount of heat generated by electrical heating using the electrodes is compensated for by an increase in the amount of heat generated by the burner heating means, and the burner heating means is effectively used to continue the transfer process. This makes it possible to more reliably reduce the temperature drop of the molten glass being transferred.

In the above configuration, the transfer device includes a fining tank, a stirring tank, and a conditioning tank formed 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 process.

In this way, discharging the molten glass from the outlet of the stirred tank promotes the transfer of molten glass from the melting furnace to the stirred tank, enabling continuous transfer of molten glass. This reduces the temperature drop of molten glass within the stirred tank and its upstream portion in the transfer device. Therefore, this configuration can prevent damage to the stirred tank and the refining tank located further upstream.

In the above configuration, the handling step may involve continuously transporting molten glass to the forming device using the transfer device, thereby continuing the supply of molten glass to the forming device.

In this way, continuous transfer processing, such as by supplying current from the aforementioned standby power supply equipment and/or heating with a burner heating means, makes it possible to continuously transfer molten glass from the upstream end of the transfer device to the downstream end. 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 could be damaged by an extreme drop in temperature, but if molten glass is continuously supplied to the forming device, the heat of the molten glass supplied significantly reduces the temperature drop. Therefore, this configuration prevents damage to all of the transfer pipes of the transfer device and the forming device (especially the forming body).

In the above configuration, when the transfer continuation process is performed in the countermeasure process, the flow rate of molten glass transferred by the transfer device may be less than the flow rate of molten glass transferred by the transfer device in the transfer process.

This makes it possible to reduce the capacity of the standby power supply equipment and the heat output of the burner heating means, preventing increases in equipment costs and the complexity of the equipment.

According to the present invention, in the event of a disruption 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 progression of solidification of the molten glass can be appropriately prevented.

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. 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. 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. 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. 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. 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. 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.

The method for manufacturing a glass article according to an embodiment of the present invention will now be described with reference to the accompanying drawings.

Figure 1 illustrates the basic configuration of a manufacturing apparatus for carrying out the glass article manufacturing method according to the present invention. As shown in the figure, this manufacturing apparatus 1 broadly comprises a melting furnace 2 located at the upstream end and which heats glass raw materials to produce molten glass Gm, a transfer device 3 which transfers the molten glass Gm flowing out of the melting furnace 2 downstream, and a forming device 4 which forms a glass ribbon Gr using the molten glass Gm supplied from the transfer device 3.

The melting furnace 2 defines a melting space within the furnace with walls made of firebricks or the like. The bottom wall 2a of the melting furnace 2 is provided with multiple electrodes Px that protrude into the furnace and are immersed in the molten glass Gm. These electrodes Px electrically heat the molten glass Gm. In this case, the molten glass Gm in the melting furnace 2 may be heated solely by electrically heating the electrodes Px, or in addition, a burner heating means 17, described below, may also be used. The melting furnace 2 is provided with a raw material feeder (e.g., a screw feeder) that supplies glass raw materials onto the molten glass Gm from outside the furnace.

The transfer device 3 mainly comprises, from upstream to downstream, a fining tank 5, a stirring tank 6, and a conditioning tank 7. The inlet 5a of the fining tank 5 is connected to the outlet 2b of the melting furnace 2 via an upstream connecting pipe 8. The outlet 5b of the fining tank 5 is connected to the inlet 6a of the stirring tank 6 via a midstream connecting pipe 9. The outlet 6b of the stirring tank 6 is connected to the inlet 7a of the conditioning tank 7 via a cooling pipe 10. The upstream connecting pipe 8, midstream connecting pipe 9, and cooling pipe 10 are also components of the transfer device 3.

The fining tank 5 performs a fining process on the molten glass Gm produced in the melting furnace 2. The stirring tank 6 performs a homogenization process on the molten glass Gm that has been subjected to the fining process by stirring it with stirring blades (stirrers) 6x. The cooling pipe 10 cools the molten glass Gm that has been subjected to the homogenization process and adjusts its viscosity and other properties. The condition adjustment tank 7 further adjusts the viscosity and flow rate of the cooled molten glass Gm. Note that multiple stirring tanks 6 may be arranged on the transfer path of the transfer device 3.

The refining vessel 5, the upstream connecting pipe 8, the midstream connecting pipe 9, and the cooling pipe 10 are all composed of transfer pipes P, and more specifically, horizontal transfer pipes P1 as shown in Figure 2. The horizontal transfer pipes P1 have pipe axes Z extending horizontally. Here, when the horizontal transfer pipes P1 form the refining vessel 5 and the midstream connecting pipe 9, their pipe axes Z extend horizontally (including slightly inclined directions). When the horizontal transfer pipes P1 form the upstream connecting pipe 8 and the cooling pipe 10, their pipe axes Z extend in an inclined direction that gradually rises as they move downstream. The horizontal transfer pipes P1 include a tubular portion Pa through which molten glass Gm flows, flange portions Pb provided at one and the other ends of the tubular portion Pa in the axial 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 tank 5, upstream connecting pipe 8, midstream connecting pipe 9, and cooling pipe 10 may each be configured by connecting multiple horizontal transfer pipes P1.

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 part 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.

The stirring vessel 6 is composed of a transfer pipe P, specifically a vertical transfer pipe P2 as shown in Figure 3. This vertical transfer pipe P2 differs 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 flanges Pb at the upper and lower ends of the tubular portion Pa. The upper flange Pb, like the flange Pb of the horizontal transfer pipe P1, has an opening corresponding to the inner circumferential surface of the tubular portion Pa. However, the lower flange Pb is a blind flange without such an opening. The lower flange Pb also has a drain port (see Figure 7 below) for discharging molten glass. Furthermore, the upper and lower peripheral walls of the tubular portion Pa of the vertical transfer pipe P2 are formed with the inlet 6a and outlet 6b, respectively. 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 by 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 the transfer pipe P, and although there are differences in shape and other aspects from the vertical transfer pipe P2 shown in the illustration, a similar configuration can be used.

Referring to FIG. 1, the forming device 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 device 3 and a small-diameter pipe 13 that is a component of the condition adjustment tank 7. Therefore, in this embodiment, the downstream end of the transfer device 3 is the outlet 13b of the small-diameter pipe 13 in the condition adjustment tank 7. The upstream end of the transfer device 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 device 4 in this embodiment, it may also be a component of the transfer device 3.

The glass ribbon Gr formed into a strip is supplied to the annealing process and cutting process, where glass sheets of the desired dimensions are cut out as glass articles. The glass sheets obtained here have a thickness of, for example, 0.01 to 2 mm and are used as glass substrates or cover glass for displays such as liquid crystal displays and organic electroluminescent displays. The forming device 4 may also be one that implements other downdraw methods, such as the slot downdraw method, or one that implements methods other than the downdraw method, such as the float method.

Silicate glass and silica glass are used as the glass for the plate glass, preferably borosilicate glass, soda-lime glass, aluminosilicate glass, or chemically strengthened glass, and most preferably alkali-free glass. Here, alkali-free glass refers to glass that is substantially free of alkali components (alkali metal oxides), and specifically glass with an alkali component weight ratio of 3000 ppm or less. In this embodiment, the alkali component weight ratio is preferably 1000 ppm or less, more preferably 500 ppm or less, and most preferably 300 ppm or less.

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

Next, we will explain in detail the manufacturing method of a glass article according to an embodiment of the present invention.

As shown in Figure 4, this manufacturing method comprises a melting process S1, a transporting process S2, a molding process S3, and a treating process S4.

The melting step S1 is a step in which molten glass Gm is produced from glass raw materials by electrically heating the molten glass Gm using electrodes Px in the melting furnace 2 with current supplied from the operating power supply equipment 15.

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 electrodes Py with current supplied from the operating power supply equipment 15.

The forming process S3 is a process in which a glass article is formed using the forming device 4 from the molten glass Gm transported by each transfer pipe P of the transfer device 3.

Response step S4 is a step for responding to any interruptions in the supply of current from the operating power supply equipment 15. In this response step S4, a transfer continuation process is performed to continue transferring the molten glass Gm from the melting furnace 2 at least partway to the transfer device 3. Note that, if the operating power supply equipment 15 receives power from an electric power company, an interruption in the supply of current occurs when a power outage occurs or when the operating power supply equipment 15 breaks down. Also, if the operating power supply equipment 15 generates its own power, an interruption in the supply of current occurs when the operating power supply equipment 15 breaks down. Furthermore, if the operating power supply equipment 15 includes both equipment that receives power from an electric power company and equipment that generates its own power, an interruption in the supply of current occurs when either or both of these equipment experience a power outage or breakdown.

The benefits of performing the transfer continuation process in response step S4 are as follows. Specifically, when a current supply interruption occurs as described above, molten glass Gm continues to be transferred at least partway up the transfer device 3. Therefore, the heat of this continuously transferred molten glass Gm reduces the temperature drop in the transfer pipe P located at least upstream 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 molten glass Gm causes the molten glass Gm to continue flowing within the melting furnace 2, appropriately stopping the solidification of the molten glass Gm not only within the transfer pipe P but also within the melting furnace 2. As a result, once the current supply from the operating power supply equipment 15 is restored, the transfer of molten glass Gm can be resumed with only simple or no repair work performed on the transfer pipe P or the melting furnace 2.

Below, we will explain first to fourth examples of the transfer continuation process performed in response step S4.

Figure 5 is a schematic side view illustrating a first example of the continuous transfer process. As shown in the figure, this first example includes a backup power supply 16 that can be used in the event of a disruption in the current supply from the operating power supply 15. With this basic configuration, in the countermeasure step S4, current is supplied from the backup 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 backup power supply 16 enables 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 due to the cessation of the supply of molten glass Gm or a sudden rise in temperature occurs due to the resumption of the supply of molten glass Gm. 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 molten glass Gm being transferred is set to be less than the flow rate B of the molten glass Gm being transferred during the transfer step S2. Preferably, the flow rate A is set to 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, preventing increased equipment costs and increased 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 by a 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 backup 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 reverse may also be true, or the capacities may be the same.

Figure 6 is a schematic side view illustrating a second example of the continuous transfer 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. In the melting step S1, molten glass Gm is produced solely by electrical heating using the electrodes Px of the melting furnace 2. Based on this basic configuration, in the countermeasure step S4, molten glass Gm is produced in the melting furnace 2 using the burner heating means 17. In this manner, the burner heating means 17 provides the heating necessary to produce molten glass Gm, thereby more reliably reducing the temperature drop of the continuously transferred molten glass Gm. In this second example, 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. Furthermore, since the flow rate of molten glass Gm transferred when this second example is performed is the same as in the first example described above, the amount of heat generated by the burner heating means 17 can be reduced, preventing increases in equipment costs, etc. This second example may be used in conjunction 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.

The burner heating means 17 can be composed of, for example, multiple burners arranged on the side wall of the melting furnace 2, and each burner heats the glass raw materials and 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 treatment step S4, the burners may be installed.

A third example of the transfer continuation process will be described with reference to the same figure. In this third example, molten glass Gm is generated in the melting step S1 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. Based on 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 increased 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 described above. Therefore, this third example achieves the same effects as the second example described above. This third example may be used in conjunction 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.

Increasing 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.

Figure 7 is a schematic side view illustrating a fourth example of the transfer continuation process. As shown in the figure, 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 molding 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, 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 within 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. Instead of the configuration described here, a drain port may be formed in the transfer device 3 at a location other than the stirring tank 6, and the molten glass Gm may be discharged from that drain port. This fourth example may be used in combination with the above-described first example, or with either the second or third example, or with a combination of the first and second examples, or with a combination of the first and third examples.

The above describes a method for manufacturing a glass article according to an embodiment of the present invention, but the present invention is not limited to this, and various variations are possible without departing from the spirit of the invention.

For example, in the above embodiment, the present invention is applied to a method for manufacturing sheet glass, but the present invention may also be applied to a method for manufacturing glass articles other than sheet glass (e.g., glass rolls, glass tubes, glass fibers, etc.).

In the above embodiments, first to fourth examples have been given as examples of continuous transfer processes for continuously transferring molten glass within the transfer pipe. However, other processes may be performed, or may be used in combination, as long as they allow molten glass to be continuously transferred within the transfer pipe in the event of a current supply interruption. For example, in the countermeasure step S4, it is preferable to supply glass frits onto the molten glass Gm from outside the furnace. The glass frits may be supplied intermittently or continuously. Furthermore, a raw material supply machine may be used to supply the glass frits, or the glass frits may be added manually. If a raw material supply machine is used in the countermeasure step S4, it is preferable to supply current to the raw material supply machine from the standby power supply equipment 16.

1 Manufacturing device 2 Melting furnace 3 Transfer device 4 Molding device 5 Refining tank 6 Stirring tank 6d Bottom of stirring tank (bottom wall)
6e Discharge port (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 Constituent element of molding device (molded body)
13 Small diameter pipe of conditioning tank 13b Downstream end of transfer pipe (outlet of conditioning tank)
15 Operating power supply equipment 16 Standby power supply equipment 17 Burner heating means Gm Molten glass P Transfer pipe P1 Horizontal transfer pipe P2 Vertical transfer pipe Pa Tubular portion Pb Flange portion Px Melting furnace electrode Py Transfer pipe electrode S1 Melting process S2 Transfer process S3 Forming process S4 Treatment process

Claims (6)

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 . 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. 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. 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. 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. A method for manufacturing a glass article according to any one of claims 1 to 4, wherein in the treatment step, the transfer device continuously transfers the molten glass to the forming device, thereby continuously supplying the molten glass to the forming device.