JP7118359B2 - Method for manufacturing glass article - Google Patents

Description

The present invention relates to a method for manufacturing glass articles.

In the method of manufacturing a glass article, frit is melted in a melting furnace to form molten glass, and then the molten glass flowing out from an outlet provided downstream of the melting furnace is shaped by a transfer channel (also called a feeder). While transferring to the apparatus, the transferred molten glass is formed into a predetermined shape (for example, plate shape) according to the glass article in the forming apparatus.

Here, in a melting furnace, frit and/or molten glass may be heated by electric heating by electrodes (see, for example, Patent Document 1).

Japanese Unexamined Patent Application Publication No. 2003-183031

By the way, if a transfer channel becomes unusable due to a sudden failure or deterioration, etc., the unusable transfer channel should be replaced with a new transfer channel, and the usable melting furnace should continue to be used as it is. is economical.

However, conventionally, there is no method for safely replacing the transfer channel while leaving the melting furnace as it is.

An object of the present invention is to safely replace the transfer channel while leaving the melting furnace as it is.

The present invention, which has been devised to solve the above problems, comprises a melting process for continuously forming molten glass by melting raw materials for frit in a melting furnace, and transferring the molten glass flowing out of the outlet of the melting furnace through a transfer channel. and a forming step of forming the molten glass transferred in the transfer channel into a glass article by means of a forming apparatus, in a state in which a blocking member is arranged so as to block the outlet, It is characterized by further comprising a replacement step of replacing the transfer channel. According to such a configuration, since the outlet of the melting furnace is closed by the blocking member, it is possible to prevent the molten glass in the melting furnace from flowing out from the outlet when the transfer channel is replaced. . Therefore, the transfer channel can be safely replaced while the melting furnace remains intact.

In the above configuration, in the replacement step, it is preferable to lower the temperature of the molten glass at least in the most upstream transfer channel before closing the outlet with the blocking member. In this way, as the temperature of the molten glass is lowered in the most upstream transfer channel, the molten glass around the outlet of the melting furnace becomes highly viscous and its fluidity is reduced. As a result, the molten glass in the melting furnace slowly flows out from the outlet of the melting furnace, so that the work of arranging the blocking member can be easily performed.

Said structure WHEREIN: It is preferable that the interruption|blocking member is provided with the cooling structure. In this way, the shutoff member cools the molten glass around the outlet of the melting furnace, and the molten glass around the outlet is maintained at a high viscosity. Therefore, it is possible to reliably prevent the molten glass from leaking out from the outlet of the melting furnace where the blocking member is arranged. Moreover, since thermal deformation of the blocking member can also be prevented, the state in which the outflow port of the melting furnace is blocked by the blocking member can be stably maintained.

Said structure WHEREIN: A melting furnace may be equipped with the electrode which electrically heats a molten glass. In this case, electric heating using electrodes and heating by other heating means such as a burner (combustion of gas fuel) may be used together.

Said structure WHEREIN: It is preferable that the interruption|blocking member is equipped with an insulation structure. In this way, even if the electrodes continue to energize and heat the melting furnace during the replacement process, it is possible to prevent electrical leakage to the transfer channel side. Therefore, it is possible to safely replace the transfer channel.

In the above configuration, the electrode is preferably a bottom electrode provided on the bottom wall of the melting furnace. By doing so, the erosion of the melting furnace can be improved, and the service life of the melting furnace can be extended. Therefore, the life of the melting furnace can be significantly longer than the life of the transfer channel, and the effect of replacing the transfer channel while leaving the melting furnace is more pronounced.

In the above configuration, in the melting step, it is preferable that the frit is melted only by electrical heating using electrodes. In this way, the amount of water vapor in the molten glass does not increase due to the combustion of the gaseous fuel in the melting furnace, so the amount of water in the molten glass can be easily reduced. Therefore, the water content of the glass article is necessarily reduced, and there is an advantage that the thermal dimensional stability is improved.

Said structure WHEREIN: It is preferable that a melting furnace contains a zirconia-type refractory. By doing so, the erosion of the melting furnace can be improved and the service life of the melting furnace can be further extended, so that the effect of replacing the transfer flow path while leaving the melting furnace is more remarkable.

In the above configuration, the number of transfer channels connected to the melting furnace may be one.

In the above configuration, the melting space for melting the frit in the melting furnace may consist of a single space.

According to the invention, the transfer channel can be safely replaced while leaving the melting furnace as it is.

BRIEF DESCRIPTION OF THE DRAWINGS It is a side view which shows the manufacturing apparatus of the glass article which concerns on 1st embodiment. It is a sectional view showing the circumference of the melting furnace of the manufacturing device of the glass article concerning a first embodiment. It is a figure for demonstrating the exchange process included in the manufacturing method of the glass article which concerns on 1st embodiment, Comprising: It is sectional drawing which shows the state of a melting furnace periphery. It is a figure for demonstrating the exchange process included in the manufacturing method of the glass article which concerns on 1st embodiment, Comprising: It is sectional drawing which shows the state of a melting furnace periphery. It is a figure for demonstrating the exchange process included in the manufacturing method of the glass article which concerns on 1st embodiment, Comprising: It is sectional drawing which shows the state of a melting furnace periphery. FIG. 4 is a diagram for explaining the insulation structure of the blocking member used in the method for manufacturing the glass article according to the first embodiment, and is a cross-sectional view of the periphery of the blocking member. FIG. 4 is a front view of the shielding member for explaining the cooling structure of the shielding member used in the method for manufacturing the glass article according to the first embodiment. It is sectional drawing for demonstrating the exchange process included in the manufacturing method of the glass article which concerns on 2nd embodiment. It is sectional drawing for demonstrating the exchange process included in the manufacturing method of the glass article which concerns on 2nd embodiment. It is sectional drawing for demonstrating the exchange process included in the manufacturing method of the glass article which concerns on 3rd embodiment. It is sectional drawing for demonstrating the exchange process included in the manufacturing method of the glass article which concerns on 3rd embodiment.

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

(First embodiment)
As shown in FIG. 1, the manufacturing apparatus used in the method for manufacturing a glass article according to the first embodiment includes a melting furnace 1, a transfer channel 2, and a forming apparatus 3 in order from the upstream side.

The melting furnace 1 is for carrying out a melting process for continuously forming molten glass Gm. In this embodiment, the molten glass Gm consists of alkali-free glass. Alkali-free glass has a glass composition of, for example, SiO ₂ 50 to 70%, Al ₂ O ₃ 12 to 25%, B ₂ O ₃ 0 to 12%, Li ₂ O + Na ₂ O + K ₂ O (Li ₂ O, Na ₂ O and K ₂ O) 0-1%, MgO 0-8%, CaO 0-15%, SrO 0-12%, BaO 0-15%. The electrical resistivity of the molten glass Gm made of alkali-free glass is generally high, for example, 100 Ω·cm or more at the heating temperature of the melting furnace 1 of 1500°C.

The molten glass Gm is not limited to alkali-free glass, and may be, for example, soda glass, borosilicate glass, aluminosilicate glass, or the like.

The transfer channel 2 is for carrying out a transfer step of transferring the molten glass Gm from the melting furnace 1 toward the molding device 3 . The transfer channel 2 includes a clarification chamber 4, a homogenization chamber (stirring chamber) 5, a pot 6, and transfer pipes 7 to 10 connecting these parts. The clarification chamber 4, homogenization chamber (stirring chamber) 5, pot 6 and transfer pipes 7-10 can be made of platinum or a platinum alloy and are electrically heated as necessary. As used herein, the terms "chamber" and "pot", such as the fining chamber 4, are intended to include those having a trough-like structure and those having a tubular structure.

The fining chamber 4 is for carrying out a fining step of fining (debubbling) the molten glass Gm supplied from the melting furnace 1 by the action of a fining agent or the like.

The homogenization chamber 5 is for performing a homogenization process of stirring and homogenizing the clarified molten glass Gm with a stirring blade 5a. The homogenization chamber 5 may be a series of homogenization chambers. In this case, it is preferable to connect the upper end of one of two adjacent homogenizing chambers and the lower end of the other with a transfer pipe.

The pot 6 is for carrying out a conditioning process for adjusting the molten glass Gm to a state (for example, viscosity) suitable for molding. Pot 6 may be omitted.

The transfer pipes 7 to 10 are composed of cylindrical pipes, for example, and transfer the molten glass Gm laterally (substantially horizontally). In this embodiment, the most upstream transfer pipe 7 in the transfer channel 2 is inclined such that the downstream end is positioned higher than the upstream end.

The molding device 3 is for carrying out a molding process for molding the molten glass Gm into a desired shape. In this embodiment, the forming apparatus 3 is formed of a formed body that continuously forms the glass ribbon G from the molten glass Gm by the overflow downdraw method.

The molding apparatus 3 may perform other down-draw methods such as the slot down-draw method, or the float method.

In the case of the overflow down-draw method, the molten glass Gm supplied to the molding device 3 overflows from a groove formed at the top of the molding device 3. By joining at , the plate-like glass ribbon G is continuously formed. The formed glass ribbon G is annealed and then cut into a predetermined size to produce a sheet glass as a glass article.

The manufactured plate glass has a thickness of, for example, 0.01 to 10 mm (preferably 0.1 to 3 mm), and is used as a substrate for flat panel displays such as liquid crystal displays and organic EL displays, organic EL lighting, solar cells, and the like. Used for protective cover.

As shown in FIG. 2, in the production stage, the melting furnace 1 melts frit (which may include cullet) Gr by heating including electric heating to continuously form molten glass Gm. Molten glass Gm continuously formed in the melting furnace 1 flows into the transfer pipe 7 from the outlet 1 a of the melting furnace 1 .

The melting furnace 1 defines a melting space within the furnace by walls made of a refractory material. Examples of refractories include zirconia-based electrocast bricks, alumina-based electrocast bricks, alumina-zirconia-based electrocast bricks, AZS (Al--Zr--Si)-based electrocast bricks, and dense sintered bricks. In the embodiment, the melting furnace 1 includes zirconia-based electroformed bricks (zirconia-based refractories) that are resistant to erosion even at high temperatures, at least in the wall portions that come into contact with the molten glass Gm. The zirconia refractory is preferably a high zirconia refractory with a zirconia content of 80 to 99%.

A bottom wall portion 1b of the melting furnace 1 is provided with a plurality of bottom electrodes 11 immersed in the molten glass Gm for electrical heating. In the present embodiment, in the production stage (melting process) for continuously forming the molten glass Gm, so-called all-electric melting is performed in which the frit Gr is continuously melted only by the electrical heating of the bottom electrode 11 . In the case of all-electric melting, there are advantages such as a small environmental load due to exhaust gas, a low moisture content of the produced sheet glass, and improved thermal dimensional stability.

The bottom electrode 11 is made of molybdenum (Mo), for example. The shape of the bottom electrode 11 is not particularly limited, and may be plate-like or block-like, but in this embodiment it is rod-like.

The electrodes may be side electrodes (not shown) provided on the side wall portion 1c of the melting furnace 1 . Alternatively, the bottom electrode 11 and side electrodes may be used together. However, since the side wall portion 1c of the melting furnace 1 is originally a portion that is easily eroded by the influence of the convection of the molten glass Gm, if the side electrode is provided and the side wall portion 1c is heated to a high temperature, the side wall portion 1c is more easily eroded. Therefore, it is preferable that only the bottom electrode 11, which is less likely to be corroded in the melting furnace 1, be used as the electrode to extend the service life of the melting furnace 1. In this case, the service life (lifetime) of the melting furnace 1 tends to be longer than the service life (lifetime) of the transfer channel 2 . For this reason, the transfer channel 2 often deteriorates before the melting furnace 1, and it is particularly useful to replace the transfer channel 2 while leaving the melting furnace 1 as it is.

A raw material charging device 12 is provided on the upstream side of the melting furnace 1 . The material charging device 12 is not particularly limited, and may be, for example, a pusher or a vibrating feeder, but is a screw feeder in this embodiment.

In the production stage, the raw material charging device 12 sequentially supplies the frit Gr such that a part of the liquid surface Gm1 of the molten glass Gm is not covered with the frit Gr. That is, the melting furnace 1 is a so-called semi-hot top type.

The melting furnace 1 may be a so-called cold top type in which the entire liquid surface Gm1 of the molten glass Gm is covered with the frit Gr in the production stage.

The melting furnace 1 is provided with a flue 13 as a gas discharge path for discharging the gas inside the melting furnace 1 to the outside. A fan 13a is provided in the flue 13 for sending gas to the outside.

In this embodiment, the melting space of the melting furnace 1 is a single melter consisting of a single space, and is a single feeder with one transfer channel 2 connected to the melting furnace 1 .

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

As described above, this manufacturing method includes a melting process, a transfer process, and a molding process in the production stage. Among these, the transfer process includes a clarification process, a homogenization process, and a conditioning process. The melting process, transfer process, and molding process are the same as those described in conjunction with the configuration of the manufacturing apparatus described above, so detailed descriptions thereof will be omitted.

As shown in FIGS. 3 to 5, this manufacturing method further includes a replacement step of replacing the transfer channel 2 in a state where the blocking member 14 is arranged so as to block the outlet 1a of the melting furnace 1. FIG. This replacement process is a process performed in a non-production stage when the transfer process is not performed due to some reason such as failure or deterioration of the transfer channel 2 .

In the replacement step, first, as shown in FIG. 3, the electric power supply amount for energization heating of the transfer pipe 7 positioned at the most upstream portion is made smaller than that in the production stage, thereby reducing the molten glass Gm in the transfer pipe 7. Cool down. Here, the term "reducing the amount of electric power supplied for electric heating to a level lower than that in the production stage" includes the case where electric heating is stopped. From the viewpoint of energy cost, in order to lower the temperature of the molten glass Gm in the transfer pipe 7, it is preferable to stop the electric heating of the transfer pipe 7, and it is more preferable to stop all the electric heating in the transfer passage 2. . It should be noted that the transfer channel 2 may be positively cooled from the outside with a cooling fluid such as water or air.

By lowering the temperature of the molten glass Gm in the transfer pipe 7 in this manner, the molten glass Gm around the outlet 1a of the melting furnace 1 becomes highly viscous and its fluidity is lowered. As a result, for example, a high-viscosity glass layer Gs is formed inside the transfer pipe 7 and around the outlet 1a. The temperature of the molten glass Gm in the transfer pipe 7 is preferably lowered until the flow of the molten glass Gm in the transfer pipe 7 is completely stopped.

Here, the high-viscosity glass layer Gs is a glass layer whose fluidity is significantly lower than that of the molten glass Gm at the production stage, or a glass layer with no fluidity (including cooled and solidified glass). The viscosity of the high-viscosity glass layer Gs is, for example, 10 ⁶ to 10 ³⁰ dPa·s.

In the case of a single feeder, since the molten glass Gm cannot be supplied to the downstream side during the replacement process, it is preferable to stop charging the frit Gr by the raw material charging device 12 as in the state of FIG.

Next, with the high-viscosity glass layer Gs formed around the outlet 1a of the melting furnace 1, as shown in FIG. .

Furthermore, at the same time or after separating the transfer channel 2 from the melting furnace 1, as shown in FIG. With the outlet 1a of the melting furnace 1 blocked by the blocking member 14 in this way, the transfer channel 2 is replaced with a new one. In this embodiment, the transfer channel 2 and the molding device 3 are also replaced with new ones. However, the blocking member 14 is removed from the outlet 1a of the melting furnace 1 immediately before joining the new transfer channel 2 to the outlet 1a of the melting furnace 1. In this way, the outlet 1a of the melting furnace 1 is blocked by the blocking member 14 during almost the entire period of the replacement process. can be prevented from flowing out from the outflow port 1a. Therefore, the transfer channel 2 can be safely replaced while leaving the melting furnace 1 as it is.

Further, in the present embodiment, the high-viscosity glass layer Gs is formed around the outlet 1a of the melting furnace 1 by lowering the temperature of the molten glass Gm in the transfer pipe 7 when the blocking member 14 is arranged. , the molten glass Gm in the melting furnace 1 is difficult to flow out from the outlet 1a. In particular, when the outlet 1a of the melting furnace 1 is completely blocked by the high-viscosity glass layer Gs, the molten glass Gm in the melting furnace 1 is more difficult to flow out from the outlet 1a. Therefore, the work of arranging the blocking member 14 can be easily performed.

Here, when the wall portion of the melting furnace 1 contains a zirconia-based refractory (especially, a high-zirconia-based refractory), the crystal structure of the portion in contact with the molten glass Gm changes when the temperature drops too much. This may cause delamination of the surface layer of the zirconia-based refractory. When such delamination occurs, it becomes necessary to replace the refractories of the melting furnace 1, increasing the cost required for the replacement process. Therefore, it is preferable to maintain the temperature in the melting furnace 1 at a predetermined temperature or higher by, for example, electrically heating the molten glass Gm with the bottom electrode 11 even during the replacement step.

From the viewpoint of preventing delamination of the melting furnace 1, the temperature in the melting furnace 1 is preferably 1200°C or higher, more preferably 1250°C or higher, and even more preferably 1300°C or higher. However, in the case of a single feeder, since the molten glass Gm is not continuously formed during the replacement process, from the viewpoint of energy cost, the amount of power supply for electric heating is reduced compared to the production stage, and the temperature in the melting furnace 1 is increased. , preferably lower than the production stage temperature. The temperature in the melting furnace 1 is preferably 1600° C. or lower, more preferably 1500° C. or lower, and even more preferably 1450° C. or lower. Here, the temperature inside the melting furnace 1 means the temperature of the molten glass Gm excluding the high-viscosity glass layer Gs and its surroundings.

Since the high-viscosity glass layer Gs is formed around the outlet 1a of the melting furnace 1, the temperature of the zirconia-based refractory at the outlet 1a of the melting furnace 1 is also lower than 1200°C, and the surface layer of the zirconia-based refractory is delaminated. can occur. In order to prevent this, the outlet 1a of the melting furnace 1 preferably covers the surface of the zirconia-based refractory with platinum or a platinum alloy. In addition, the surface of the zirconia refractory is coated with platinum or a platinum alloy for the portion of the wall of the melting furnace 1 that is in contact with the high-viscosity glass layer Gs and the low-temperature molten glass Gm around it and becomes lower than 1200 ° C. preferably covered with By covering the surface of the zirconia-based refractory with platinum or a platinum alloy, the zirconia-based refractory does not come into direct contact with the molten glass Gm, but comes into contact with the molten glass Gm via platinum or a platinum alloy, preventing delamination. can.

As shown in FIG. 6, the blocking member 14 has an insulating structure. In the present embodiment, the blocking member 14 has an insulating structure including a main body member 15, an insulating member 16 abutting against the main body member 15, and holding the main body member 15 while pressing the main body member 15 toward the melting furnace 1 through the insulating member 16. and a holding member 17 . As a result, in the replacement step, it is possible to prevent electric leakage to the transfer flow path 2 side even if the electric heating by the electrodes is continued in the melting furnace 1 .

The body member 15 is made of, for example, a metal plate such as stainless steel, and the insulating member 16 is made of, for example, ceramics. The main body member 15 may be made of glass or a refractory material. In the case of glass or a refractory material, the body member 15 is easily adhered to the molten glass Gm in the melting furnace 1. It may become difficult to separate from the outlet 1a. Therefore, it is preferable that the main body member 15 is a metal plate.

In the case of a single melter, since the melting space is small and the area heated by the electrodes 11 is often close to the outlet 1a of the melting furnace 1, such an insulating structure is particularly useful. The blocking member 14 is preferably grounded. In addition, since the high-viscosity glass layer Gs also has an insulating effect, insulation may be performed by sufficiently lowering the temperature of the high-viscosity glass layer Gs. Also, the insulating action of the high-viscosity glass layer Gs and the insulating structure of the blocking member 14 may be used together.

As shown in FIG. 7, the blocking member 14 has a cooling structure. In the present embodiment, the main body member 15 of the blocking member 14 has a cooling flow path 15a as a cooling structure through which a cooling fluid such as water or air flows. Body member 15 is preferably a water-cooled plate. The cooling flow path 15a is supplied with a cooling fluid from one end and discharged from the other end. The cooling channel 15 a is formed in a region of the body member 15 corresponding to at least the outlet 1 a of the melting furnace 1 . At least a part of the supply/discharge pipe 18 connected to the cooling flow path 15a for supplying/discharging the cooling fluid is also preferably made of an insulating pipe made of ceramics, rubber, or the like. When an insulating pipe made of rubber is used as part of the supply/discharge pipe 18, it is preferable to separate the insulating pipe from the melting furnace 1 and the cooling channel 15a, which are heat sources, to prevent damage to the insulating pipe due to heat.

The cooling structure of the blocking member 14 is not limited to circulating the cooling fluid in the cooling flow path 15a, and for example, the cooling fluid may be sprayed onto the main body member 15 from the outside.

After completion of the replacement process as described above, production (melting process, transfer process and molding process) is restarted. When restarting production, for example, after removing the blocking member 14 and connecting the transfer channel 2 to the melting furnace 1, the temperature of the transfer channel 2 may be raised by electrical heating. Thereby, the molten glass Gm is supplied from the melting furnace 1 to the transfer flow path 2 . Further, the viscosity of the high-viscosity glass layer Gs around the outflow port 1a gradually decreases and disappears. When the feeding of the frit Gr is stopped in the single feeder, the feeding of the frit Gr is restarted according to the connection between the melting furnace 1 and the transfer passage 2 . When the temperature in the melting furnace 1 is lower than the temperature in the production stage with a single feeder, the temperature in the melting furnace 1 is raised to the temperature in the production stage before connecting the melting furnace 1 and the transfer channel 2 .

(Second embodiment)
As shown in FIGS. 8 and 9, the method for manufacturing a glass article according to the second embodiment differs from the method for manufacturing a glass article according to the first embodiment in the replacement step of replacing the transfer channel 2. be. In the following, differences from the first embodiment will be mainly described, and detailed descriptions of common points with the first embodiment will be omitted.

In order to carry out a smooth replacement process, the manufacturing apparatus used in the method for manufacturing a glass article according to the second embodiment is arranged immediately downstream of the outlet 1a of the melting furnace 1, that is, the outlet 1a of the melting furnace 1, Between the transfer channel 2 and the upstream end of the transfer pipe 7, there is provided an accommodation chamber 21 in which a blocking member 14 is accommodated so as to be vertically movable. When the blocking member 14 is raised, the passage of the storage chamber 21 is opened, and when the blocking member 14 is lowered, the passage of the storage chamber 21 is closed.

The blocking member 14 is not limited to a configuration that moves up and down as long as it can open and close the flow path of the storage chamber 21 . The blocking member 14 may be configured to move horizontally, for example.

The blocking member 14 preferably has an insulating structure and a cooling structure, as in the first embodiment.

In the replacement step included in the manufacturing method of the glass article according to the second embodiment, as shown in FIG. , the blocking member 14 is lowered to close the passage of the storage chamber 21 . As a result, the outlet 1a of the melting furnace 1 is blocked by the blocking member 14. As shown in FIG.

In the state where the blocking member 14 is lowered to close the flow path of the storage chamber 21, the transfer flow path 2 is separated from the storage chamber 21 as shown in FIG. and molding device 3) are replaced with new ones.

After the replacement step is completed, the blocking member 14 is raised after the temperature of the storage chamber 21 is raised, and the flow path of the storage chamber 21 is reopened to resume production.

The blocking member 14 housed in the housing chamber 21 can easily close the flow path of the housing chamber 21 even when the molten glass Gm has a low viscosity. For this reason, after closing the flow path of the accommodation chamber 21 by lowering the blocking member 14, the amount of power supply for the electrical heating of the transfer tube 7 is made smaller than that in the production stage, so that the molten glass Gm in the melting tube 7 may be cooled.

In the production stage, the blocking member 14 is arranged outside the housing chamber 21, and an opening (not shown) provided in the housing chamber 21 for inserting the blocking member 14 during the replacement process is closed with a lid or the like. It is preferable that it is dry.

(Third embodiment)
As shown in FIGS. 10 and 11, the method for manufacturing a glass article according to the third embodiment differs from the method for manufacturing a glass article according to the first embodiment in the replacement step of replacing the transfer channel 2. be. In the following, differences from the first embodiment will be mainly described, and detailed descriptions of common points with the first embodiment will be omitted.

In the replacement step included in the method for manufacturing a glass article according to the third embodiment, first, as shown in FIG. of molten glass Gm is discharged. As a result, the height of the liquid surface Gm1 of the molten glass Gm is lowered below the outflow port 1a. Of course, all of the molten glass Gm may be discharged from the melting furnace 1 .

Next, as shown in FIG. 11, the transfer channel 2 is separated from the melting furnace 1 and the outflow port 1a is closed with a blocking member 14. Next, as shown in FIG. With the outlet 1a blocked by the blocking member 14 in this manner, the transfer channel 2 (or the transfer channel 2 and the molding device 3) is replaced with a new one.

The blocking member 14 preferably has an insulating structure and a cooling structure, as in the first embodiment.

The blocking member 14 is removed from the outlet 1a of the melting furnace 1 just before joining the new transfer channel 2 to the outlet 1a of the melting furnace 1 . For example, after forming the molten glass Gm in the melting furnace 1 and raising the liquid level Gm1 of the molten glass Gm to a predetermined height (for example, the liquid level at the production stage), the blocking member 14 is removed. A new transfer channel 2 may be joined to the outlet 1 a of the melting furnace 1 . Conversely, for example, after removing the blocking member 14 and joining a new transfer channel 2 to the outlet 1a of the melting furnace 1, the molten glass Gm is formed in the melting furnace 1, and the liquid surface of the molten glass Gm is Gm1 may be raised again to a predetermined height.

After the replacement process is completed, production resumes. In this embodiment, since the amount of molten glass Gm in the melting furnace 1 is reduced in the replacement step, the molten glass Gm having a different glass composition may be replaced when restarting production.

Here, when the wall portion of the melting furnace 1 contains zirconia-based refractories, it is preferable to keep the temperature inside the melting furnace 1 at a predetermined temperature or higher even during the replacement process in order to prevent delamination. However, when the height of the liquid surface Gm1 of the molten glass Gm in the melting furnace 1 is lowered, part of the bottom electrode 11 may be exposed to the air. If electrical heating is performed by the bottom electrode 11 in this state, the bottom electrode 11 may be quickly worn out due to oxidation. Therefore, it is preferable to heat the inside of the melting furnace 1 by another heating means such as a burner, without performing electric heating by the bottom electrode 11 . In this way, when the electric heating by the electrodes is not performed in the melting furnace 1 during the replacement process, the blocking member 14 does not have to have an insulating structure.

The present invention is not limited to the configurations of the above-described embodiments, nor is it limited to the above-described effects. Various modifications can be made to the present invention without departing from the gist of the present invention.

In the above embodiment, the case of a single melter has been explained, but a multi-melter having a plurality of melting spaces connected together may be used. In the case of a multi-melter, for example, only the most upstream melting space is electrically heated by electrodes, and the downstream melting space is not electrically heated by electrodes. In this case, since the area to be electrically heated by the electrodes and the outlet of the melting furnace are largely separated from each other through the molten glass Gm that functions as a resistor, the shielding member does not need to have an insulating structure.

In the above embodiment, the case of a single feeder has been described, but a multi-feeder may be used in which a plurality of transfer channels extending toward a plurality of molding apparatuses are connected to a melting furnace. In the case of a multi-feeder, it is possible to continue manufacturing glass articles by supplying molten glass from the melting furnace to the rest of the transfer channels even while the replacement process is being performed for some of the plurality of transfer channels. can. Therefore, it is preferable to feed frit into the melting furnace even while the exchange process is being performed for some of the plurality of transfer channels.

In the above embodiment, the blocking member is arranged at the outlet of the melting furnace, but the blocking member is also accommodated in the middle of the transfer channel (for example, between the downstream end of the clarification chamber and the upstream end of the homogenization chamber). A containment room may be provided. In this case, in the replacement step, the flow of the molten glass in the transfer channel can be easily stopped by closing the blocking member of the storage chamber provided in the middle of the transfer channel. As a method for stopping the flow of the molten glass in the transfer channel, for example, a method such as plugging a vertical tube portion such as a pod with an outer peripheral surface of a rod-shaped member (plunger) may be used.

In the above embodiments, electrical heating may be supplementary with electrical heating means such as, for example, heaters, prior to commencing continuous formation of molten glass (start-up stage of the melting furnace) and/or during the production stage.

In the above embodiment, the melting furnace may use both electric heating and gas fuel combustion in the production stage. When gaseous fuel combustion is used, burners are provided on the side walls of the melting furnace or the like. Even in the case of all-electric melting in the production stage, heating by burners can be used in the start-up stage of the melting furnace.

In the above embodiments, the case where the glass article molded by the molding apparatus is plate glass has been described, but the present invention is not limited to this. The glass article molded by the molding apparatus may be, for example, a glass roll obtained by winding a glass film into a roll, an optical glass component, a glass tube, a glass block, a glass fiber, or the like, and may be of any shape. good.

1 melting furnace 1a outlet 1b bottom wall 2 transfer channel (feeder)
3 Forming device 4 Clarifying chamber 5 Homogenizing chamber 6 Pots 7 to 10 Transfer pipe 11 Bottom electrode 12 Raw material charging device 13 Flue duct 14 Blocking member 15 Body member 15a Cooling channel 16 Insulating member 17 Holding member 18 Supply/discharge pipe 21 Storage chamber G Glass ribbon Gm Molten glass Gr Glass raw material Gs High viscosity glass layer

Claims (9)

By electric heating with electrodes, A melting step of continuously forming molten glass by melting frit in a melting furnace, a transfer step of transferring the molten glass flowing out of the outlet of the melting furnace through a transfer channel, and a transfer channel through which the molten glass is transferred. A method for manufacturing a glass article comprising a molding step of molding molten glass into a glass article in a molding apparatus,
leaving the molten glass in the melting furnace and The method further comprises a replacement step of replacing the transfer channel with a blocking member arranged to block the outlet.,
During the replacement step, the molten glass left in the melting furnace is electrically heated by the electrodes.A method for producing a glass article characterized by: 2. The method for manufacturing a glass article according to claim 1, wherein in the replacing step, the temperature of the molten glass in the transfer channel at least at the most upstream portion is lowered before closing the outlet with the blocking member. . 3. The method for manufacturing a glass article according to claim 1, wherein the blocking member has a cooling structure. The method for manufacturing a glass article according to any one of claims 1 to 3, wherein the blocking member has an insulating structure. The method for producing a glass article according to any one of claims 1 to 4 , wherein the electrode comprises a bottom electrode provided on the bottom wall of the melting furnace. The method for producing a glass article according to any one of claims 1 to 5 , wherein in the melting step, the frit is melted only by electric heating using the electrode. The method for producing a glass article according to any one of claims 1 to 6 , wherein the melting furnace contains a zirconia-based refractory. The method for producing a glass article according to any one of claims 1 to 7 , characterized in that the number of transfer channels connected to the melting furnace is one. The method for producing a glass article according to any one of claims 1 to 8 , characterized in that the melting space for melting the frit of the melting furnace consists of a single space.

Images