JP7063153B2 - Manufacturing method of glass articles - Google Patents

Description

The present invention relates to a method for manufacturing a glass article, and more particularly to a method for manufacturing a glass article including a replacement step of exchanging a transfer device for transferring the molten glass flowing out of the melting furnace to a molding means.

As is well known, when manufacturing a glass article, the molten glass flowing out of the melting furnace is supplied to the molding device by a transfer device. The transfer device has a transfer container for transferring the molten glass. The melting furnace plays a role of heating and melting the glass raw material and sending the molten glass to the transfer device.

As an example, Patent Document 1 discloses a melting furnace and a transfer device including a plurality of transfer containers. Examples of the transfer container include a clarification pipe, a stirring pot, a cooling pipe, and a pot in order from the upstream side. The transfer flow path including these transfer containers is usually formed of a member made of thin-walled platinum or a platinum alloy at least at a portion in contact with the molten glass during operation.

Japanese Unexamined Patent Publication No. 2014-19629

By the way, when the transfer device is deteriorated over time or has a failure, the transfer device is repaired and replaced with the repaired transfer device or a new transfer device. At this time, the actual situation is that the transfer device is once removed from the melting furnace, and after a predetermined period of time has elapsed, the repaired or new transfer device is attached to the melting furnace.

When the melting furnace from which the transfer device has been removed is left as it is after the heating is stopped at the time of replacement of the transfer device, the molten glass in the melting furnace is solidified (including semi-solidification). Therefore, at the time of restarting, there arises a problem that the temperature raising process for turning the solidified glass into molten glass is prolonged, and the labor and labor for the temperature rising are increased.

To solve this problem, it is possible to keep the melting furnace heated and hold the molten glass in the melting furnace after the transfer device is removed and before the replacement is completed. Conceivable. However, if the melting furnace is kept heated, the molten glass in the melting furnace is cooked. The melting furnace contains, for example, a refractory material such as zirconia, and a plate material made of a thin-walled precious metal (for example, platinum or platinum alloy) is attached to an appropriate position on the inner wall surface thereof.

Therefore, in the melting furnace, platinum, zirconia, etc. melt into the cooked molten glass. When the molten glass flows through the transfer device at the time of restarting, needle-shaped foreign matter (hereinafter referred to as needle-shaped lumps) made of precious metal or the like is generated due to the stirring action in the stirring pot. Further, when the molten glass is supplied to, for example, a molded body of a molding means for performing an overflow down draw method, needle-shaped lumps adhere to the wall surface of the molded body.

In such a state, when the molten glass supplied from the melting furnace to the molding means through the transfer device flows down the wall surfaces on both sides of the molded body, the needle-shaped lumps adhering to the wall surfaces on both sides are the molten glass. Transfer to the contact surface of. Then, the plate glass obtained by fusing these molten glasses at the lower end of the molded body is in a state where needle-shaped lumps are inserted in the portion corresponding to the mating surface at the time of fusing. These needle-shaped lumps are defects and may cause fatal problems such as product defects. Moreover, since the needle-shaped lumps are in a state of sticking to the wall surface of the molded body, product defects due to the needle-shaped lumps cannot be eliminated until a long period of time (for example, about 1 month or 2 months) has passed.

From the above viewpoint, the present invention prevents an unreasonable foreign substance from being mixed in the molten glass to be supplied to the molding means between the time when the transfer device is replaced and the time when the restart is performed, and from the start of the restart. The subject is to be able to manufacture high-quality glass articles.

The present invention, which was devised to solve the above problems, comprises a melting step of heating and melting a glass raw material in a melting furnace to produce molten glass, and a transfer step of transferring the molten glass produced in the melting furnace by a transfer device. A method for manufacturing a glass article comprising a molding step of molding molten glass supplied from the transfer device into a predetermined shape by a molding means, wherein the transfer step and the molding step are interrupted and the melting furnace is used. It has an exchange step of exchanging the transfer device with the molten glass held in the melting glass, and the melting process is performed between the time when the transfer device is attached to the melting furnace and the time when the molding process is started. It is characterized by performing a preparatory process for discharging the molten glass in the transfer device to the outside while flowing the molten glass from the furnace into the transfer device.

According to such a method, the heating by the melting furnace is not stopped until the transfer device is attached to the melting furnace in the transfer device replacement process, so that the glass is not solidified in the melting furnace and is melted. You will be in a state of holding glass. When the transfer device is attached to the melting furnace, the molten glass flows from the melting furnace into the transfer device by executing the preparatory process. The molten glass flows through the transfer device and is discharged from the transfer device before being supplied to the molding means. This operation is performed, for example, until the entire amount of the molten glass containing platinum or the like produced in the melting furnace is completely discharged to the outside through the transfer device. Therefore, at the start of the molding process, it is possible to reduce the concentration of unreasonable foreign substances such as needle-shaped lumps in the molten glass supplied from the melting furnace to the molding means through the transfer device. As a result, it is possible to reduce the entry of unreasonable foreign matter into the glass article manufactured through the molding means from the start of the restart. As a result, it is possible to prevent the occurrence of product defects and the like.

In the method described above, the molten glass may be discharged to the outside through a drain hole opened in the inner bottom surface of the stirring pot provided in the transfer device when the preparatory process is executed.

By doing so, since the temperature of the molten glass in the stirring pot is lower than the temperature of the molten glass in the melting furnace or the clarification tank, the molten glass can be discharged to the outside at a suitable flow rate, and the discharged melting can be performed. The glass is easy to handle.

In this case, it is preferable that the transfer device is provided with a plurality of the stirring pots, and the molten glass is discharged to the outside through drain holes opened in the inner bottom surfaces of all the stirring pots at the time of executing the preparatory process.

By doing so, the time until the entire amount of the molten glass containing platinum or the like produced in the melting furnace is discharged from the transfer device is shortened. By this. It is possible to efficiently discharge the molten glass while properly adjusting the flow rate of the molten glass discharged from the transfer device.

In the method described above, the transfer device includes a clarification tank arranged on the upstream side of the stirring pot and a gate arranged between the clarification tank and the stirring pot, and when the preparation step is executed, the transfer device is described. It is preferable to adjust the flow rate of the molten glass by changing the opening degree of the flow path of the transfer device by the gate.

Here, the flow rate of the molten glass discharged from the inside of the transfer device to the outside can be adjusted by changing the temperature of the molten glass in the melting furnace, the clarification tank, and the stirring pot, respectively, but the temperature of the molten glass in the preparatory treatment. If the difference between the temperature at the time of operation and the temperature at the time of operation is large, it takes time to adjust the temperature of the molten glass after the preparatory treatment is completed. Therefore, there is a limit to the flow rate adjustment depending on the temperature of the molten glass. In the method here, since the flow rate of the molten glass is adjusted by changing the opening degree of the flow path at the gate, it is easy to maintain the temperature of the molten glass in the melting furnace or the clarification tank at a desired temperature. It becomes possible to adjust the flow rate.

In the above method, the upper layer portion of the molten glass of the melting furnace is discharged to the outside by the overflow device provided in the melting furnace between the start of the replacement step and the start of the preparation process. May be good.

Here, since the transfer device is removed from the melting furnace from the start of the replacement process to the start of the preparatory process, the molten glass in the melting furnace may be in a cooked state. However, in the method here, the upper layer portion of the molten glass of the melting furnace is discharged to the outside by the overflow device, so that the molten glass flows. This makes it difficult for the molten glass to be cooked in the melting furnace, and it is possible to suppress an increase in the concentration of platinum or the like. When discharging the upper layer portion of the molten glass from the melting furnace to the outside, the glass raw material should be appropriately replenished in the melting furnace to keep the liquid level height of the molten glass constant in the melting furnace. Is preferable.

In the above method, at the time of executing the preparatory process, the molten glass of the melting furnace is discharged from the transfer device to the outside while flowing into the transfer device from below the overflow portion of the overflow device. Is preferable.

Here, even if the upper layer portion of the molten glass overflows from the melting furnace by the overflow device as described above, foreign substances such as platinum and zirconia remain in the middle layer portion and the lower layer portion of the molten glass. obtain. However, in the method here, when the preparatory treatment is executed, the molten glass is made to flow into the transfer device from below the overflow portion of the melting furnace and is discharged to the outside. As a result, the middle layer portion and the lower layer portion of the molten glass in which foreign matter such as platinum may remain can flow into the transfer device and then be discharged to the outside.

In the above method, when the melting furnace is a single melter provided with one melting space, the total amount W1 (kg) of the molten glass discharged from the inside of the transfer device to the outside in the preparatory treatment is melted in the exchange step. The ratio (W1 / W2) to the total amount W2 (kg) of the molten glass held in the furnace is preferably 1 or more. When the melting furnace is a multi-melter in which a plurality of melting spaces are connected, the total amount W1 (kg) of the molten glass discharged from the inside of the transfer device to the outside in the preparatory process is the total amount W1 (kg) of the plurality of melting spaces in the exchange step. The ratio (W1 / W3) to the total amount W3 (kg) of the molten glass held in the molten space located at the most downstream of the inside is preferably 1 or more.

In this way, most of the molten glass stored in the melting furnace is discharged from the transfer device to the outside. As a result, it is possible to prevent the molten glass stored in the melting furnace and having an increased concentration of platinum or the like from being supplied to the molding means.

According to the present invention, it is possible to reduce the concentration of unreasonable foreign matter in the molten glass to be supplied to the molding means between the time when the transfer device is replaced and the time when the restart is performed, and the concentration is high from the start of the restart. It becomes possible to manufacture high-quality glass articles.

It is a schematic side view which shows the whole structure of the manufacturing apparatus for carrying out the manufacturing method of the glass article which concerns on embodiment of this invention. It is a vertical sectional side view which shows the transfer apparatus which is the main part of the manufacturing apparatus for carrying out the manufacturing method of the glass article which concerns on embodiment of this invention. It is a vertical sectional side view which shows the structure of the main part in the exchange process in the manufacturing apparatus for carrying out the manufacturing method of the glass article which concerns on embodiment of this invention. It is a vertical sectional side view which shows the structure of the main part in the exchange process in the manufacturing apparatus for carrying out the manufacturing method of the glass article which concerns on embodiment of this invention. It is a vertical sectional front view cut along the line AA of FIG. It is a vertical sectional side view which shows the state of the main part which performs the preparatory treatment in the manufacturing method of the glass article which concerns on embodiment of this invention.

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.

FIG. 1 illustrates a manufacturing apparatus for carrying out the method for manufacturing a glass article according to the present invention. As shown in the figure, the manufacturing apparatus 1 is roughly divided into a melting furnace 2 deployed at the upstream end for heating and melting the glass raw material, and the molten glass Gm flowing out of the melting furnace 2 is transferred to the molding means 4. The transfer device 3 is provided with a transfer device 3 and a molding means 4 for forming the molten glass Gm supplied from the transfer device 3 into a strip-shaped flat glass Gp.

The melting furnace 2 generates molten glass Gm by heating and melting the glass raw material, and continues to send a predetermined amount of molten glass Gm to the transfer device 3 while accumulating a large capacity of the molten glass Gm.

The transfer device 3 includes a clarification tank 5, an attached tank 6 attached to the clarification tank 5, a plurality of (two in the example) stirring pots 7, 8 and a cooling pipe 9 in order from the upstream side as a transfer container. , And a pot 10. Each of these transfer containers 5 to 10 has an inflow port into which the molten glass Gm flows in and an outflow port into which the molten glass Gm flows out.

More specifically, the clarification tank 5 removes air bubbles in the molten glass, and an attached tank 6 is connected to the downstream side of the clarification tank 5. On the downstream side of the attached tank 6, a first stirring pot 7 on the upstream side and a second stirring pot 8 on the downstream side for homogenizing the molten glass Gm are arranged. The stirring pots 7 and 8 during operation of the manufacturing apparatus 1 contain stirring blades (stirrers) 7x and 8x that rotate around the axis, respectively. A cooling pipe 9 is adjacently arranged on the downstream side of the second stirring pot 8, and a pot 10 as a volume portion mainly for adjusting the viscosity of the molten glass Gm is arranged adjacently on the downstream side of the cooling pipe 9. Has been done. The downstream side of the cooling pipe 9 is inclined upward.

The molding means 4 has a molded body 11 that forms the molten glass Gm by the overflow down draw method, and a large-diameter introduction pipe 12 that guides the molten glass Gm to the molded body 11. The molten glass Gm is supplied to the introduction pipe 12 from the pot 10 of the transfer device 3.

FIG. 2 is an enlarged vertical cross-sectional view simply showing the melting furnace 2 and the transfer device 3 in operation.

As shown in the figure, in the melting furnace 2, the molten glass Gm at about 1700 ° C. is put into the internal space surrounded by the bottom wall portion 2c, the side wall portion 2d, and the upper wall portion 2e. Generate. The bottom wall portion 2c and the side wall portion 2d include a zirconia-based refractory material. A thin plate made of a precious metal (for example, platinum or a platinum alloy) is attached to the outlet 2b and its periphery in the side wall portion 2d of the melting furnace 2 (not shown). From the melting furnace 2, a fixed amount of molten glass Gm is continuously supplied to the transfer device 3 per unit time. By continuously replenishing and charging the glass raw material into the melting furnace 2, the liquid level height of the molten glass Gm in the melting furnace 2 is maintained substantially constant.

The outlet 2b of the melting furnace 2 is formed in the lower part of the side wall portion (side wall portion on the downstream side) 2d thereof. The outflow port 2b communicates with the inflow port 5a of the clarification tank 5 via the upstream connection pipe 13. The outlet 5b of the clarification tank 5 overlaps with the inlet 6a of the attached tank 6 and communicates with the outlet 5b. The outflow port 6b of the attached tank 6 communicates with the inflow port 7a of the first stirring pot 7 via the intermediate connection pipe 14. The inflow port 7a of the first stirring pot 7 is provided in the upper part of the peripheral wall thereof. The outlet 7b of the first stirring pot 7 communicates with the inlet 8a of the second stirring pot 8 via the downstream connecting pipe 15. The outflow port 7b of the first stirring pot 7 is provided in the lower part of the peripheral wall thereof, and the inflow port 8a of the second stirring pot 8 is provided in the upper part of the peripheral wall thereof. These stirring pots 7 and 8 are arranged at the same height. The downstream side of the downstream connection pipe 15 is inclined upward. The outlet 8b of the second stirring pot 8 overlaps with and communicates with the inlet 9a of the cooling pipe 9. The outlet 8b of the second stirring pot 8 is provided at the lower part of the peripheral wall thereof. The downstream side of the cooling pipe 9 is inclined upward. The outlet 9b of the cooling pipe 9 overlaps with and communicates with the inlet 10a of the pot 10. The pot 10 has an upper large diameter portion 10x and a lower small diameter portion 10y. The inflow port 10a of the pot 10 is provided on the peripheral wall of the large diameter portion 10x, and the outflow port 10b is provided at the lower end of the small diameter portion 10y. The small diameter portion 10y of the pot 10 is inserted into the introduction pipe 12 of the molding means 4. The lower end of the small diameter portion 10y is immersed in the molten glass Gm in the introduction pipe 12.

In the transfer flow path composed of the transfer containers 5 to 10 and the connection pipes 13 to 15 described above, at least the portion in contact with the molten glass Gm (in this embodiment, the entire inner surface of the transfer flow path) is made of thin platinum or It is made of a member made of platinum alloy. The perimeter of these members is covered with a refractory material (not shown). The transfer flow path is energized and heated, and the temperature can be adjusted for each of the transfer containers 5 to 10 and the connection pipes 13 to 15.

The manufacturing apparatus 1 having the above configuration executes the following steps. That is, the method for manufacturing a glass article according to the present invention includes a melting step of producing molten glass Gm in the melting furnace 2 and a transfer step of transferring the molten glass Gm flowing out of the melting furnace 2 to the molding means 4 by the transfer device 3. A molding step of molding the molten glass Gm supplied from the transfer device 3 into a predetermined shape by the molding means 4 is provided. Further, this manufacturing method includes a replacement step of interrupting the transfer step and the molding step, and replacing the transfer device 3 with the molten glass Gm held in the melting furnace 2. Then, the preparatory process is executed between the time when the transfer device 3 is attached to the melting furnace 2 in the replacement process and the time when the molding process is started.

FIG. 3 illustrates a state in which the transfer device 3 is removed (separated) from the melting furnace 2 in the replacement step. This replacement process is for repairing the transfer device 3. In this embodiment, the molding means 4 is removed from the transfer device 3, but the molding means 4 may be attached to the transfer device 3. Further, in the exchange step, only the transfer device 3 may be exchanged, or the molding means 4 may be exchanged together with the transfer device 3.

As shown in the figure, the outlet 2b of the melting furnace 2 is closed by a blocking plate 16. Since the melting furnace 2 continues to be heated in the same manner as during operation, the temperature of the molten glass Gm in the melting furnace 2 is maintained at a high temperature of, for example, about 1700 ° C. Therefore, platinum, zirconia, and the like are in a state of being melted in the middle layer portion Gm1 and the lower layer portion Gm2 of the molten glass Gm in the melting furnace 2.

A duct 2f is mounted on the side wall (upstream side wall) 2d of the melting furnace 2, and the melting furnace 2 includes an overflow device configured by the duct 2f. The upper layer portion Gm3 (the portion with cross hatching) of the molten glass Gm in the melting furnace 2 is discharged to the outside through the duct 2f. Since the glass raw material is appropriately replenished in the melting furnace 2, the liquid level height of the molten glass Gm in the melting furnace 2 is maintained constant (for example, the liquid level height during operation). By performing such a process, a flow is generated in the molten glass Gm in the melting furnace 2. As a result, it becomes difficult for the molten glass Gm to be cooked in the melting furnace 2, and an increase in the concentration of platinum, zirconia, or the like can be suppressed.

In the transfer device 3, each transfer container 5 to 10 and each connection pipe 13 to 15 are all empty. Of these, the stirring blades 7x and 8x are extracted from the first and second stirring pots 7 and 8. A gate 17 for opening / closing the flow path and changing the opening / closing of the flow path is inserted in the attached tank 6. More specifically, as shown in FIGS. 4 and 5, a gap 18 is provided between the lower surface portion 6 m of the attachment tank 6 and the bottom surface portion 16 m of the gate 17. The gap 18 is a flow path (narrowed flow path) through which the molten glass Gm flows. The gate 17 opens and closes the flow path and changes the opening degree of the flow path by moving up and down by an elevating mechanism (not shown), and adjusts the flow rate of the molten glass Gm flowing toward the downstream side. A thin plate 19 made of platinum or a platinum alloy is attached to the front surface portion 17a and the back surface portion 17b of the refractory material forming the gate 17, the side surface portions 17c, and the bottom surface portion 17m. The gate 17 has a U-shape from both side surface portions 17c to the bottom surface portion 17m.

The clarification tank 5 has a pipe shape. The attached tank 6 has a pipe shape, but only the portion where the gate 17 is inserted has a U shape as shown in FIG. The flow path area of the clarification tank 5 is larger than the flow path area of the attachment tank 6, and the flow path area of the attachment tank 6 is larger than the flow path area of the intermediate connection pipe 14. Specifically, the lowest portion of the lower surface portion 5 m of the clearing tank 5, the lowest portion of the lower surface portion 6 m of the attached tank 6, and the lowest portion of the lower surface portion 14 m of the intermediate connection pipe 14 are at the same height position. The uppermost portion of the upper surface portion 5n of the clarification tank 5 is higher than the uppermost portion of the upper surface portion 6n of the attached tank 6, and the uppermost portion of the upper surface portion 6n of the attached tank 6 is the highest portion of the upper surface portion 14n of the intermediate connection pipe 14. Higher than the top.

FIG. 6 illustrates a state in which the transfer device 3 after the repair work is attached to the melting furnace 2 and the preparatory process is being executed. In this embodiment, the preparatory process is executed from the middle of the replacement process to the time when the molding means 4 is attached to the transfer device 3 and the molding process is started. If the molding means 4 is attached to the transfer device 3 at this point, the preparatory process is executed from the end of the replacement step to the start of the molding step. Further, in this embodiment, while the preparatory process is being executed, the upper layer portion Gm of the molten glass Gm is not discharged to the outside by the overflow device described above, but it may be performed.

As shown in the figure, the molten glass Gm flowing out from the outlet 2b at the lower part of the melting furnace 2 continues to flow into the transfer device 3. The molten glass Gm (particularly, the middle layer portion Gm1 and the lower layer portion Gm2) has a high concentration of platinum or the like that causes needle-like lumps. Then, as shown in the figure, the molten glass Gm settles in a state of being held while flowing at a portion from the upstream connection pipe 13 of the transfer device 3 to the second stirring pot 8. In the preparatory treatment of the present embodiment, the liquid level height of the molten glass Gm of the second stirring pot 8 is lower than that of the inflow port 9a of the cooling pipe 9, and the molten glass Gm does not flow into the cooling pipe 9. The liquid level height of the molten glass Gm of the second stirring pot 8 may be made higher than the inflow port 9a of the cooling pipe 9, and the molten glass Gm may flow into the cooling pipe 9. In the latter case, the liquid level height of the molten glass Gm of the second stirring pot 8 is made lower than the outlet 9b of the cooling pipe 9.

In the preparatory process, the flow rate of the molten glass Gm flowing into the first and second stirring pots 7 and 8 is adjusted by the gate 17. The drain holes 7g and 8g of the first and second stirring pots 7 and 8 are all open to the atmosphere. Therefore, the molten glass Gm in the first and second stirring pots 7 and 8 continues to be discharged downward through the drain holes 7 g and 8 g.

The flow path area of the drain hole 7g of the first stirring pot 7 is smaller than the flow path area of each of the inflow port 7a and the outflow port 7b of the first stirring pot 7. Further, the flow path area of the drain hole 8g of the second stirring pot 8 is also smaller than the flow path area of each of the inflow port 8a and the outflow port 8b of the second stirring pot 8. As a result, the flow rate of the molten glass Gm discharged from the drain holes 7g and 8g of the first and second stirring pots 7 and 8 becomes more suitable. Further, since the molten glass Gm is discharged from the drain holes 7g and 8g of the two stirring pots 7 and 8 at the same time, the time required for the discharge is shortened.

This preparatory treatment is performed until the concentration of platinum or the like contained in the molten glass Gm in the melting furnace 2 and the transfer device 3 is reduced to a level that does not cause a problem in the manufactured glass article. In the present embodiment, the total amount W1 (kg) of the molten glass Gm discharged from the inside of the transfer device 3 to the outside in the preparatory process is equal to the total amount W2 (kg) of the molten glass Gm held in the melting furnace 2 in the exchange step. As a result, most of the molten glass Gm accumulated in the melting furnace 2 and having an increased concentration of platinum or the like, which causes the generation of needle-shaped lumps, is discharged to the outside through the transfer device 3. As a result, the molten glass Gm having an increased concentration of platinum or the like, which is a cause of needle-like lumps, hardly remains in the melting furnace 2 and the transfer device 3. From the viewpoint of reducing the concentration of platinum and the like contained in the molten glass Gm in the melting furnace 2 and the transfer device 3, W1 / W2 can be, for example, 0.5 or more, and preferably 1 or more. On the other hand, W1 / W2 is preferably 1.5 or less from the viewpoint of preventing an increase in manufacturing cost due to discharge of molten glass Gm.

The melting furnace 2 of the present embodiment is a single melter provided with one melting space, but the melting furnace 2 may be a multi-melter in which a plurality of melting spaces are connected. In the case of a multi-melter, from the viewpoint of reducing the concentration of platinum and the like contained in the molten glass Gm in the melting furnace 2 and the transfer device 3, the total amount of the molten glass Gm held in the most downstream molten space in the exchange step is W3. If it is (kg), it is preferable that W1 / W3 is 1 or more. On the other hand, W1 / W3 is preferably 1.5 or less from the viewpoint of preventing an increase in manufacturing cost due to discharge of molten glass Gm.

After that, when starting the transfer step and the molding step, as shown in FIGS. 1 and 2, the molding means 4 is attached to the transfer device 3, and the drain holes 7g of the first and second stirring pots 7 and 8 are attached. , 8 g is closed. At this time, the gate 17 is removed from the attached tank 6, and the opening for inserting and removing the gate 17 is covered with a lid member 20 made of platinum or a platinum alloy.

Further, in the molten glass Gm existing in the melting furnace 2 and the transferring device 3 when the transfer step and the molding step are started, the concentration of platinum or the like that causes the generation of needle-shaped lumps is reduced. As a result, it is possible to reduce the entry of needle-shaped lumps and the like into the glass plate manufactured by the manufacturing apparatus 1 from the start of the molding process, and it is possible to prevent the occurrence of product defects and the like.

The present invention is not limited to the above embodiment, and various variations are possible as illustrated below.

In the above embodiment, when the preparatory process is executed, the molten glass Gm is discharged from the drain holes 7g and 8g of the first and second stirring pots 7 and 8, but the molten glass Gm is melted from other parts of the transfer device 3. The glass Gm may be discharged.

In the above embodiment, the case of having two stirring pots 7 and 8 is illustrated, but the present invention can be applied in the same manner even when having three or more stirring pots. In this case, it is preferable to discharge the molten glass Gm from all the drain holes of the three or more stirring pots when the preparatory treatment is performed.

In the above embodiment, the gate 17 is arranged in the attached tank 6, but the flow rate may be adjusted only by adjusting the temperature of the molten glass Gm without using the gate 17. Further, the location of the gate 17 may be another location as long as it is a flow path between the clarification tank 5 and the first stirring pot 7.

In the above embodiment, the gate 17 is used as a member for adjusting the flow rate of the molten glass Gm flowing through the transfer device. For example, between the clarification tank 5 and the first stirring pot 7, the peripheral wall has an inflow port and the bottom. By arranging a container with an outlet on the wall and adopting a configuration with a plunger that adjusts the amount of molten glass flowing out from the outlet (this configuration itself is well known), the plunger is a member for adjusting the flow rate. It may be used as.

In the above embodiment, the molding means 4 molds the strip-shaped flat glass Gp, but it may be molded into another shape corresponding to the glass article.

1 Manufacturing equipment 2 Melting furnace 2b Outlet 2f Duct (overflow equipment)
3 Transfer device 4 Molding means 5 Clarification tank 6 Attached tank 7 Stirring pot 7g Drain hole 8 Stirring pot 8g Drain hole 9 Cooling pipe 11 Molded body

Claims (8)

A melting step of heating and melting a glass raw material in a melting furnace to produce molten glass, a transfer step of transferring the molten glass produced in the melting furnace to a molding means by a transfer device, and a molten glass supplied from the transfer device. A method for manufacturing a glass article, comprising a molding step of molding into a predetermined shape by the molding means.
It has an exchange step of exchanging the transfer device in a state where the transfer step and the molding process are interrupted and the molten glass is held in the melting furnace.
During the period from the attachment of the transfer device to the melting furnace in the exchange step to the start of the molding process, the molten glass in the transfer device is brought to the outside while flowing the molten glass from the melting furnace into the transfer device. A method of manufacturing a glass article, characterized in that a preparatory process for discharging is performed. The method for manufacturing a glass article according to claim 1, wherein when the preparatory process is executed, the molten glass is discharged to the outside through a drain hole opened in the inner bottom surface of the stirring pot provided in the transfer device. The second aspect of the present invention, wherein the transfer device includes a plurality of the stirring pots, and discharges the molten glass to the outside through drain holes opened in the inner bottom surfaces of all the stirring pots when the preparatory process is executed. A method for manufacturing glass articles. The transfer device includes a clarification tank arranged on the upstream side of the agitation pot and a gate arranged between the clarification tank and the agitation pot.
The method for manufacturing a glass article according to claim 3, wherein the flow rate of the molten glass is adjusted by changing the opening degree of the flow path of the transfer device by the gate at the time of executing the preparation step. Claim 1 is characterized in that the upper layer portion of the molten glass of the melting furnace is discharged to the outside by an overflow device included in the melting furnace between the start of the replacement step and the start of the preparation process. The method for manufacturing a glass article according to any one of 4 to 4. The method for manufacturing a glass article according to claim 5, wherein the molten glass of the melting furnace is allowed to flow into the transfer device from below the overflow portion of the overflow device when the preparatory process is executed. The melting furnace is a single melter having one melting space.
The total amount W1 (kg) of the molten glass discharged from the inside of the transfer device to the outside in the preparatory treatment is a ratio (W1 / W2) to the total amount W2 (kg) of the molten glass held in the melting furnace in the exchange step. The method for producing a glass article according to any one of claims 1 to 6, wherein the number is 1 or more. The melting furnace is a multi-melter in which a plurality of melting spaces are connected.
The total amount W1 (kg) of the molten glass discharged from the inside of the transfer device to the outside in the preparatory treatment is the total amount of the molten glass held in the molten space located at the most downstream of the plurality of molten spaces in the exchange step. The method for producing a glass article according to any one of claims 1 to 6, wherein the ratio (W1 / W3) to W3 (kg) is 1 or more.

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