JP7092021B2 - Manufacturing method of glass articles - Google Patents

Description

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

As is well known, flat glass is used for flat panel displays such as liquid crystal displays and organic EL displays. As a method for producing flat glass, various molding methods such as a down draw method and a float method are used.

For example, the plate glass is formed into a plate shape through each step such as a melting step, a clarification step, a homogenization step, and a molding step. Patent Document 1 includes, as a manufacturing apparatus for executing each of the above steps, a melting tank, a clarification tank, a stirring tank, a molding apparatus, and a glass supply pipe for interconnecting these components. Will be disclosed. The clarification tank and the glass supply pipe are made of a platinum material (platinum or platinum alloy) having a high melting point and excellent corrosion resistance. Further, the clarification tank is provided with a vent portion (vent pipe) for discharging the gas generated from the molten glass.

Japanese Unexamined Patent Publication No. 2014-028734

Depending on the structure of the clarification tank, the molten glass may stay and the gas generated from the molten glass may not be discharged from the vent portion but may be accumulated in the clarification tank. When a gas pool is formed in the clarification tank, the platinum material constituting the clarification tank is oxidized, and the platinum oxide is mixed in the molten glass. As a result, abnormalities such as lumps occur in the manufactured flat glass, resulting in deterioration of quality and defective products.

The cause of the gas pool will be described with reference to FIG. The clarification tank C includes a tubular portion Ca and a flange portion F1 provided at an upstream end portion of the tubular portion Ca. The tubular portion Ca has a top Cb and a bottom Cc on its inner surface. The flange portion F1 is formed in a disk shape and has a circular opening O1. The diameter of the opening O1 is set smaller than the inner diameter of the tubular portion Ca. The opening portion O1 penetrates the flange portion F1 so that the lower end portion thereof coincides with the bottom portion Cc of the tubular portion Ca. In the portion above the opening O1, the wall portion of the flange portion F1 closes the end portion of the tubular portion Ca. The inside of the clarification tank C is filled with molten glass GM. That is, the liquid level of the molten glass GM is in contact with the top Cb of the tubular portion Ca.

A transfer pipe P1 is connected to the upstream end of the clarification tank C. The transfer pipe P1 has a flange portion F2 and a circular opening O2 at its downstream end. The transfer pipe P1 is connected to the clearing tank C in a state where the flange portion F2 is in contact with the flange portion F1 of the clearing tank C and the opening O2 is overlapped with the opening O1 of the clearing tank C.

In the above configuration, the molten glass GM tends to stay in the region between the top portion Cb and the wall portion of the flange portion F1 at the upstream end portion of the clarification tank C. When the gas generated from the molten glass GM floats and reaches the region where the molten glass GM stays, the gas stagnates and a gas pool GA may be generated.

The present invention has been made in view of the above circumstances, and it is a technical subject to prevent the generation of gas pools inside the clarification tank.

The present invention is for solving the above-mentioned problems, in which a step of heating and melting a glass raw material in a melting tank to generate molten glass and the molten glass flowing out from the outlet of the melting tank are transferred by a transfer pipe. A method for manufacturing a glass article, comprising: The transfer pipe includes an upstream end portion connected to the melting tank and a downstream end portion connected to the tubular portion, and the transfer pipe has the tubular portion at the top of the inner surface of the downstream end portion. It is characterized in that it is connected to the tubular portion so as to coincide with the top of the inner surface of the glass.

According to this configuration, by aligning the top of the inner surface of the transfer pipe with the top of the inner surface of the tubular portion of the clearing tank, the molten glass flowing into the clearing tank from the transfer pipe is the top and tubular portion of the inner surface of the transfer pipe. Can flow along the top of the inner surface of the glass without stagnation. Therefore, the gas generated from the molten glass can move in the clarification tank as the molten glass flows after floating. Therefore, it is possible to prevent the generation of gas pools.

The transfer pipe is said so that the top of the inner surface at the upstream end coincides with the top of the inner surface of the outlet and the bottom of the inner surface at the upstream end coincides with the bottom of the inner surface of the outlet. It may be connected to a melting tank. As a result, the molten glass can be flowed from the melting tank to the transfer pipe without staying.

The transfer pipe may be connected to the tubular portion so that the bottom of the inner surface at the downstream end thereof coincides with the bottom of the inner surface of the tubular portion. Here, when the inner diameter of the tubular portion of the clarification tank is larger than the inner diameter of the transfer pipe, the bottom of the inner surface of the tubular portion does not coincide with the bottom of the inner surface at the downstream end, so that the molten glass is around the bottom of the inner surface of the tubular portion. Is easy to stay. For example, if the bottom of the inner surface of the tubular portion is made to coincide with the bottom of the inner surface at the downstream end portion by making the inner diameter of the transfer pipe substantially equal to the inner diameter of the tubular portion, the molten glass is formed around the bottom of the inner surface of the tubular portion. Can be prevented from staying.

The transfer pipe may include an enlarged diameter portion whose inner diameter gradually increases toward the downstream end portion. This allows the transfer pipe to match the bottom of the inner surface at the downstream end with the bottom of the inner surface of the tubular, even if the inner diameter of the tubular portion of the clarification tank is larger than the inner diameter of the transfer pipe. , It is possible to prevent the molten glass from staying around the bottom of the inner surface of the tubular portion. Further, in the existing equipment in which the diameter of the outlet and the inner diameter of the tubular portion of the clarification tank are different, it is possible to prevent the generation of gas pool inside the clarification tank simply by changing the transfer pipe.

The transfer pipe is configured in a straight tubular shape, and the transfer pipe may be connected to the tubular portion so that the bottom of the inner surface at the downstream end portion is higher than the bottom of the inner surface of the tubular portion. .. Here, the outer surface of the transfer pipe is supported by a refractory material, but if the transfer pipe is provided with a diameter-expanded portion as described above, the amount of thermal expansion differs between the transfer pipe and the refractory material. A gap is likely to occur between the and. Therefore, if the transfer pipe is deformed or damaged, the usable period (life) of the transfer pipe may be shortened. If a transfer tube configured in a straight tube is adopted, the outer surface of the transfer tube can be easily supported, and the transfer tube can be maintained for a usable period. In addition, an increase in manufacturing cost of the transfer pipe can be suppressed. Further, in the existing equipment in which the diameter of the outlet and the inner diameter of the tubular portion of the clarification tank are different, it is possible to prevent the generation of gas pool inside the clarification tank simply by changing the transfer pipe.

The method may include a step of heating the transfer tube and the tubular portion in a separated state. By heating the transfer pipe and the tubular portion of the clarification tank in a separated state, the tubular portion of the transfer pipe and the clarification tank can be inflated in advance. By connecting the transfer pipe and the tubular portion of the clarification tank after expanding them, it is possible to prevent the tubular portion of the clarification tank and the transfer pipe from expanding during the clarification treatment and prevent deformation due to thermal stress.

According to the present invention, it is possible to prevent the generation of gas pools inside the clarification tank.

It is a side view which shows the manufacturing apparatus of the glass article which concerns on 1st Embodiment. It is sectional drawing of a melting tank, a clarification tank and a transfer pipe. It is a figure which shows the upstream side end part of a clarification tank and the downstream side end part of a transfer pipe. It is a flowchart which concerns on the manufacturing method of a glass article. It is sectional drawing which shows the transfer pipe and the clarification tank in a preheating process. It is sectional drawing of the melting tank, the clarification tank and the transfer pipe which concerns on 2nd Embodiment. It is sectional drawing of the clarification tank and transfer pipe which concerns on 3rd Embodiment. It is sectional drawing explaining the generation principle of a gas pool.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. 1 to 5 show a method for manufacturing a glass article and a first embodiment of a manufacturing apparatus according to the present invention.

As shown in FIG. 1, the apparatus for manufacturing a glass article according to the present embodiment has a melting tank 1, a clarification tank 2, a homogenization tank (stirring tank) 3, a pot 4, and a molded product in this order from the upstream side. 5 and glass supply paths 6a to 6d connecting these components 1 to 5 are provided. In addition, the manufacturing apparatus includes a slow cooling furnace (not shown) for slowly cooling the plate glass GR (glass article) formed by the molded body 5, and a cutting device (not shown) for cutting the plate glass GR after slow cooling.

The melting tank 1 is a container for performing a melting step of heating and melting the charged glass raw material to obtain molten glass GM. The melting tank 1 is connected to the clarification tank 2 by a glass supply path 6a. As shown in FIG. 2, the melting tank 1 has an outlet 1a for supplying the molten glass GM to the glass supply path 6a. The outlet 1a is a circular hole penetrating the wall portion 1b.

The clarification tank 2 performs a clarification step (clarification treatment) of defoaming by the action of a clarifying agent or the like while transferring the molten glass GM. The clarification tank 2 is connected to the homogenization tank 3 by a glass supply path 6b. The clarification tank 2 is formed in a tubular shape by a platinum material (platinum or platinum alloy). As shown in FIG. 2, the clarification tank 2 includes a tubular portion 7 and flange portions 8a and 8b provided at both ends of the tubular portion 7.

In FIG. 2, the flow direction of the molten glass GM is indicated by reference numeral F. Hereinafter, when the position of each component is described, the terms "upstream side" and "downstream side" are used based on the flow direction F of the molten glass GM.

The tubular portion 7 is made into a circular tube, but is not limited to this configuration. The inner diameter of the tubular portion 7 is preferably 100 mm or more and 300 mm or less. The wall thickness of the tubular portion 7 is preferably 0.3 mm or more and 3 mm or less. The length of the tubular portion 7 is preferably 300 mm or more and 10000 mm or less. These dimensions are not limited to the above range, and are appropriately set according to the type, temperature, scale of the manufacturing apparatus, and the like of the molten glass GM.

The clarification tank 2 is provided with a vent portion 7a at the top of the tubular portion 7 for discharging the gas generated in the molten glass GM. Further, the clarification tank 2 may be provided with a partition plate (obstruction plate) for changing the flow direction of the molten glass GM inside the tubular portion 7.

As shown in FIGS. 1 and 2, the liquid level GS of the molten glass GM in the melting tank 1 is set at a position above the top (apex) 7b of the inner surface of the tubular portion 7 or at the same position as the top 7b. The height difference H is set to 0 mm or more and 200 mm or less, but is not limited to this range. With this setting, the entire internal space of the tubular portion 7 is filled with the molten glass GM flowing from the melting tank 1. That is, inside the tubular portion 7, the molten glass GM comes into contact with the entire inner surface of the tubular portion 7 without separating the upper inner surface of the tubular portion 7 from the molten glass GM (see FIG. 2). In this way, when the molten glass GM comes into contact with the entire inner surface of the tubular portion 7, no gas phase space is formed in the tubular portion 7, and oxidation of the inner surface of the tubular portion 7 can be prevented. The positions of all the transfer pipes constituting the glass supply paths 6a to 6d are also set below the liquid level GS of the molten glass GM.

The flange portions 8a and 8b of the clarification tank 2 are formed in a circular shape, but are not limited to this shape. A plate-shaped protrusion for supporting the electrode may be formed on the upper portions of the flange portions 8a and 8b. The flange portions 8a and 8b are connected to a power supply device (not shown). The clarification tank 2 heats the molten glass GM flowing inside the tubular portion 7 by resistance heating (Joule heat) generated by passing an electric current through the flange portions 8a and 8b to the tubular portion 7.

The flange portions 8a and 8b of the clarification tank 2 are a first flange portion 8a provided at the upstream end portion 2a of the tubular portion 7 and a second flange provided at the downstream end portion 2b of the clarification tank 2 (tubular portion 7). Includes part 8b. The first flange portion 8a has a first opening portion 9a through which the molten glass GM flows into the tubular portion 7. The second flange portion 8b has a second opening portion 9b that allows the molten glass GM to flow out from the tubular portion 7. The first opening 9a and the second opening 9b are formed in a circular shape. The diameter of each of the openings 9a and 9b is set to be smaller than the inner diameter of the tubular portion 7.

As shown in FIGS. 2 and 3, the first opening 9a is formed corresponding to the upper part of the tubular portion 7. That is, the uppermost portion (hereinafter referred to as “upper end portion”; the same applies to other openings) 9aU in the first opening 9a coincides with the top portion 7b on the inner surface of the tubular portion 7. Similarly, the second opening 9b is formed corresponding to the upper part of the tubular portion 7. The upper end portion 9bU of the second opening portion 9b coincides with the top portion 7b on the inner surface of the tubular portion 7.

The glass supply path 6a connecting the melting tank 1 and the clarification tank 2 is composed of a transfer pipe made of a platinum material (platinum or platinum alloy). The transfer pipe 10 has a tubular portion 11 and flange portions 12a, 12b provided at both end portions 10a, 10b of the transfer pipe 10. Each of the flange portions 12a and 12b includes a first flange portion 12a formed on the upstream end portion 10a of the transfer pipe 10 and a second flange portion 12b formed on the downstream end portion 10b.

It is desirable that the inner diameter of the tubular portion 11 of the transfer pipe 10 is 100 mm or more and 300 mm or less. The wall thickness of the tubular portion 11 is preferably 0.3 mm or more and 3 mm or less. These dimensions are not limited to the above range, and are appropriately set according to the type, temperature, scale of the manufacturing apparatus, and the like of the molten glass GM. In the present embodiment, the inner diameter D of the tubular portion 11 is set smaller than the inner diameter of the tubular portion 7 related to the clarification tank 2. The tubular portion 11 is inclined upward from the dissolution tank 1 toward the clarification tank 2. The inclination angle of the tubular portion 11 with respect to the horizontal direction is set to, for example, 3 ° or more and 30 ° or less.

The first flange portion 12a of the transfer pipe 10 is in contact with the wall portion 1b of the dissolution tank 1, and the second flange portion 12b is in contact with the first flange portion 8a of the clarification tank 2 so as to face each other. Each flange portion 12a, 12b has an opening portion 13a, 13b. Each of the openings 13a and 13b is formed in an elliptical shape that is long in the vertical direction. The length DL of the major axis in each of the openings 13a and 13b is substantially equal to the inner diameter D of the tubular portion 11. Here, "substantially equal" means that the length DL of the major axis is 90% or more and 110% or less of the inner diameter D of the tubular portion 11.

The opening 13a of the first flange portion 12a is overlapped with the outlet 1a of the melting tank 1. The opening area of the opening 13a is set smaller than the opening area of the outlet 1a. The length DL of the long axis of the opening 13a related to the first flange portion 12a is substantially equal to the diameter of the outlet 1a. Here, "substantially equal" means that the length DL of the major axis is 90% or more and 110% or less of the diameter of the outlet 1a.

As shown in FIG. 2, the top portion 11a of the inner surface of the upstream end portion 10a of the transfer pipe 10 coincides with the top portion of the inner surface of the outlet 1a related to the melting tank 1. That is, the upper end portion 13aU of the opening portion 13a of the transfer pipe 10 coincides with the upper end portion 1aU of the outlet 1a. The bottom portion 11b of the inner surface of the upstream end portion 10a of the transfer pipe 10 coincides with the bottom portion of the outlet 1a. That is, the lower end portion 13aD of the opening portion 13a of the transfer pipe 10 coincides with the lower end portion 1aD of the outlet 1a.

The opening 13b of the second flange portion 12b is overlapped with the first opening 9a of the first flange portion 8a related to the clarification tank 2. The opening area of the opening 13b is set smaller than the opening area of the first opening 9a of the clarification tank 2. The length DL of the major axis in the opening 13b is substantially equal to the diameter of the first opening 9a of the clarification tank 2. That is, the length DL of the major axis is 90% or more and 110% or less of the diameter of the first opening 9a.

The top portion 11a of the inner surface of the downstream end portion 10b of the transfer pipe 10 coincides with the top portion 7b of the inner surface of the clarification tank 2. That is, the upper end portion 13bU of the opening portion 13b in the downstream end portion 10b of the transfer pipe 10 coincides with the upper end portion 9aU of the first opening portion 9a of the clarification tank 2. Further, the lower end portion 13bD of the opening portion 13b of the transfer pipe 10 coincides with the lower end portion 9aD of the first opening portion 9a of the clarification tank 2.

The glass supply path 6b connecting the clarification tank 2 and the homogenization tank 3 is composed of a transfer pipe made of a platinum material (platinum or platinum alloy). The transfer pipe 14 has a straight tubular structure and is connected to the downstream end portion 2b of the clarification tank 2. As shown in FIG. 2, the transfer pipe 14 has a tubular portion 15 and flange portions 16a, 16b and openings 17a, 17b provided at both end portions 14a, 14b of the transfer pipe 14.

It is desirable that the inner diameter of the tubular portion 15 of the transfer pipe 14 is 100 mm or more and 300 mm or less. The wall thickness of the tubular portion 15 is preferably 0.3 mm or more and 3 mm or less. These dimensions are not limited to the above range, and are appropriately set according to the type, temperature, scale of the manufacturing apparatus, and the like of the molten glass GM. In the present embodiment, the inner diameter of the tubular portion 15 is set smaller than the inner diameter of the tubular portion 7 related to the clarification tank 2.

Each of the flange portions 16a and 16b is formed in a disk shape. Each of the openings 17a and 17b is formed in a circular shape. The opening area of the openings 17a and 17b is substantially equal to the opening area of the second opening 9b in the second flange 8b of the clarification tank 2. With this configuration, the entire circumference of the opening 17a at the upstream end 14a of the transfer pipe 14 is arranged so as to coincide with the entire circumference of the second opening 9b of the clarification tank 2.

The flange portions 12a, 12b, 16a, 16b of the transfer pipes 10 and 14 are connected to a power supply device (not shown). In each of the glass supply paths 6a and 6b, similarly to the clarification tank 2, resistance heating (Joule heat) generated by passing an electric current through the flange portions 12a, 12b, 16a and 16b to the tubular portions 11 and 15 causes the glass supply passages 6a and 6b. The molten glass GM flowing inside the transfer pipes 10 and 14 is heated (the same applies to the other glass supply paths 6c and 6d).

The homogenization tank 3 is a container made of a platinum material for performing a step of stirring and homogenizing the clarified molten glass GM (homogenization step). The homogenization tank 3 includes a stirrer 3a having a stirring blade. The homogenization tank 3 is connected to the pot 4 by a glass supply path 6c. The glass supply path 6c is composed of a transfer tube made of a platinum material (platinum or platinum alloy), similarly to the above glass supply paths 6a and 6b.

The pot 4 is a container for performing a state adjusting step of adjusting the molten glass GM to a state suitable for molding. The pot 4 is exemplified as a volume portion for adjusting the viscosity and adjusting the flow rate of the molten glass GM. The pot 4 is connected to the molded body 5 by a glass supply path 6d. The glass supply path 6d is composed of a transfer tube made of a platinum material (platinum or platinum alloy), similarly to the above glass supply paths 6a to 6c.

The molded body 5 forms the molten glass GM into a desired shape. In the present embodiment, the molded body 5 forms the molten glass GM into a plate shape by the overflow down draw method. Specifically, the molded body 5 has a substantially wedge-shaped cross-sectional shape (cross-sectional shape orthogonal to the paper surface of FIG. 1), and an overflow groove (not shown) is formed on the upper portion of the molded body 5. Has been done.

The molded body 5 causes the molten glass GM to overflow from the overflow groove and flows down along the side wall surfaces (side surfaces located on the front and back sides of the paper surface) on both sides of the molded body 5. The molded body 5 fuses the flowed molten glass GM at the lower top portion of the side wall surface. As a result, the strip-shaped flat glass GR is formed. The molded body 5 may execute another down-draw method such as the slot down-draw method. Further, instead of the molded body 5, a molding device using the float method may be deployed.

The flat glass GR thus obtained has a thickness of, for example, 0.01 to 10 mm, and is used for flat panel displays such as liquid crystal displays and organic EL displays, substrates for organic EL lighting, solar cells, and protective covers. Will be done. The glass article according to the present invention is not limited to the flat glass GR, and includes a glass tube and other objects having various shapes. For example, when forming a glass tube, a molding apparatus using the Dunner method is deployed instead of the molded body 5.

As the material of the flat glass GR, silicate glass and silica glass are used, preferably borosilicate glass, soda lime glass, aluminosilicate glass and chemically strengthened glass are used, and most preferably non-alkali glass is used. Here, the non-alkali glass is a glass that does not substantially contain an alkaline component (alkali metal oxide), and specifically, a glass having a weight ratio of an alkaline component of 3000 ppm or less. be. The weight ratio of the alkaline component in the present invention is preferably 1000 ppm or less, more preferably 500 ppm or less, and most preferably 300 ppm or less.

Hereinafter, a method of manufacturing a glass article (flat glass GR) by the manufacturing apparatus having the above configuration will be described. As shown in FIG. 4, this method mainly includes a preheating step S1, an assembly step S2, a melting step S3, a molten glass supply step S4, a molding step S5, a slow cooling step S6, and a cutting step S7.

In the preheating step S1, each component 1 to 5, 6a to 6d of the manufacturing apparatus is individually separated, and the temperature is raised. As an example, FIG. 5 shows a state in which the transfer pipe 10 and the clarification tank 2 are separated. In the preheating step S1, the outlet 1a of the melting tank 1 is closed by the closing member. In the preheating step S1, each component 1 to 5, 6a to 6d is heated to a predetermined temperature. By this heating, the portion made of platinum material in each of the components 1 to 5, 6a to 6d expands. For example, the tubular portion 7 of the clarification tank 2 and the tubular portion 11 of the transfer pipe 10 expand in the longitudinal direction thereof, as shown by the two-dot chain line in FIG.

In the assembly step S2, the separated components 1 to 5 and 6a to 6d are connected to each other to assemble the manufacturing apparatus. For example, the upstream end 10a of the transfer pipe 10 is connected to the outlet 1a of the melting tank 1. Specifically, the first flange portion 12a of the transfer pipe 10 is brought into contact with the wall portion 1b of the melting tank 1, and the opening portion 13a is overlapped with the outlet 1a.

Next, the downstream end 10b of the transfer pipe 10 is connected to the upstream end 2a of the clarification tank 2. That is, the second flange portion 12b of the transfer pipe 10 and the first flange portion 8a of the clarification tank 2 face each other and are brought into contact with each other. At this time, the flange portions 8a and 12b are overlapped so that the upper end portion 9aU of the first opening portion 9a of the clarification tank 2 coincides with the upper end portion 13bU of the opening portion 13b of the transfer pipe 10.

After that, the transfer pipe 14 is connected to the clarification tank 2. That is, the flange portion 16a of the transfer pipe 14 and the second flange portion 8b of the clarification tank 2 face each other and are brought into contact with each other. At this time, the flange portions 8b and 16a are overlapped so that the opening 17a in the transfer pipe 14 coincides with the second opening 9b in the clarification tank 2.

Further, by connecting the homogenization tank 3, the pot 4, the molded body 5, and the glass supply paths 6c and 6d, the manufacturing apparatus is assembled.

In the melting step S3, the glass raw material supplied into the melting tank 1 is heated to generate molten glass GM. In addition, in order to shorten the start-up period of the manufacturing apparatus, the molten glass GM may be generated in advance in the melting tank 1 before the assembly step S2.

In the molten glass supply step S4, the molten glass GM of the melting tank 1 is sequentially transferred to the clarification tank 2, the homogenization tank 3, the pot 4, and the molded body 5 via the glass supply paths 6a to 6d. In the molten glass supply step S4, when the molten glass GM circulates in the tubular portion 7 of the clarification tank 2, gas (foam) is generated from the molten glass GM by the action of the clarifying agent blended in the glass raw material. This gas is discharged to the outside from the vent portion 7a of the clarification tank 2 (clarification step). Further, in the homogenization tank 3, the molten glass GM is stirred and homogenized (homogenization step). When the molten glass GM passes through the pot 4 and the glass supply path 6d, its state (for example, viscosity and flow rate) is adjusted (state adjustment step).

In the molding step S5, the molten glass GM is supplied to the molded body 5 through the molten glass supply step S4. The molded body 5 causes the molten glass GM to overflow from the overflow groove and flow down along the side wall surface thereof. The molded body 5 forms a strip-shaped flat glass GR by fusing the flowed molten glass GM at the lower top portion.

After that, the strip-shaped flat glass GR is cooled by the slow cooling furnace in the slow cooling step S6, and is cut by the cutting device in the cutting step S7. As a result, a plate glass (glass article) having a predetermined size is cut out from the strip-shaped plate glass GR. Alternatively, after removing both ends of the plate glass GR in the width direction in the cutting step S7, the strip-shaped plate glass GR may be wound into a roll to obtain a glass roll as a glass article (winding step).

According to the method for manufacturing a glass article according to the present embodiment described above, the top portion 11a (opening portion) of the inner surface of the downstream end portion 10b of the transfer pipe 10 in a state where the transfer pipe 10 and the clarification tank 2 are connected. The molten glass flowing into the clarification tank 2 from the transfer pipe 10 by aligning the upper end portion 13bU of 13b with the top portion 7b of the inner surface of the upstream end portion 2a of the clarification tank 2 (the upper end portion 9aU of the first opening 9a). The GM can flow along the top 11a of the transfer pipe 10 and the top 7b of the clarification tank 2 without staying. Therefore, the gas generated from the molten glass GM moves in the clarification tank 2 without generating a gas pool with the flow of the molten glass GM, and is surely discharged from the vent portion 7a. Further, even if gas is generated from the molten glass GM around the bottom 7c of the clarification tank 2, the gas floats. It is surely discharged.

Here, in the manufacturing apparatus according to the first embodiment, the molten glass GM tends to stay around the bottom 7c of the clarification tank 2, and in particular, the molten glass GM stays around the bottom 7c of the upstream end 2a of the clarification tank 2. Cheap. In this case, the accumulated molten glass GM may be deteriorated. From the viewpoint of preventing this, it is preferable to adopt the second embodiment or the third embodiment described later.

FIG. 6 shows a part of the manufacturing apparatus according to the second embodiment. In the manufacturing apparatus according to the present embodiment, the tubular portion 11 of the transfer pipe 10 includes a straight tubular first tubular portion 11A and a tapered second tubular portion 11B. The first tubular portion 11A is formed on the upstream end portion 10a side of the transfer pipe 10 and is connected to the melting tank 1. The second tubular portion 11B is formed on the downstream end portion 10b side of the transfer pipe 10 and is connected to the clarification tank 2.

The second tubular portion 11B is composed of an enlarged diameter portion whose inner diameter gradually increases from the middle portion of the transfer pipe 10 toward the downstream end portion 10b. With this configuration, the opening 13b of the downstream end 10b of the transfer pipe 10 is formed in a circular shape.

The inner diameter of the second tubular portion 11B at the downstream end portion 10b of the transfer pipe 10 is substantially equal to the inner diameter of the tubular portion 7 of the clarification tank 2. That is, the diameter of the opening 13b related to the downstream end portion 10b of the transfer pipe 10 is 90% or more and 110% or less of the inner diameter of the tubular portion 7 related to the clarification tank 2. Further, the diameter of the first opening 9a formed in the first flange portion 8a of the clarification tank 2 is substantially equal to the inner diameter of the tubular portion 7. With this configuration, the bottom 13bD in the opening 13b of the second tubular portion 11B of the transfer pipe 10 coincides with the bottom 9aD in the first opening 9a of the upstream end 2a of the clarification tank 2. As a result, the molten glass GM flowing into the clarification tank 2 from the transfer pipe 10 not only flows along the top 11a of the transfer pipe 10 and the top 7b of the clarification tank 2 without staying, but also flows at the bottom 11b of the transfer pipe 10. And flows along the bottom 7c of the clarification tank 2 without staying.

FIG. 7 shows a part of the manufacturing apparatus according to the third embodiment. In the second embodiment described above, the second tubular portion 11B of the transfer pipe 10 is configured as a diameter-expanded portion, but the second tubular portion 11B of the transfer pipe 10 according to the present embodiment has a constant inner diameter. It is configured in a tubular shape.

The opening 13b of the downstream end portion 10b of the transfer pipe 10 (second tubular portion 11B) is formed in an elliptical shape long in the vertical direction as in the first embodiment. In the third embodiment, unlike the first embodiment, the length DL of the long axis in the opening 13b is substantially equal to the inner diameter of the tubular portion 7 of the clarification tank 2. Therefore, also in this embodiment, the bottom portion 13bD in the opening portion 13b of the second tubular portion 11B of the transfer pipe 10 coincides with the bottom portion 9aD in the first opening portion 9a of the upstream end portion 2a of the clarification tank 2. Therefore, the molten glass GM flowing from the transfer pipe 10 into the clarification tank 2 not only flows along the top 11a of the transfer pipe 10 and the top 7b of the clarification tank 2 without staying, but also flows at the bottom 11b of the transfer pipe 10 and It flows along the bottom 7c of the clarification tank 2 without staying.

The present invention is not limited to the configuration of the above embodiment, and is not limited to the above-mentioned action and effect. The present invention can be modified in various ways without departing from the gist of the present invention.

In the above second embodiment, an example in which the enlarged diameter portion (second tubular portion 11B) is provided in the range from the middle portion of the transfer pipe 10 to the downstream end portion 10b is shown, but the present invention is limited to this configuration. It is not something that will be done. For example, the tubular portion 11 may be configured as a diameter-expanded portion over the entire length from the upstream side end portion 10a to the downstream side end portion 10b of the transfer pipe 10.

1 Dissolution tank 1a Outlet 1aU Outlet top (top)
2 Clarification tank 7 Tubular part 7b Top of the inner surface of the tubular part 10 Transfer pipe 10a Upstream side end 10b Downstream side end 11a Top of the inner surface of the transfer pipe 11B Second tubular part (diameter expansion part)
GM molten glass GR flat glass (glass article)
S1 preheating process S3 melting process S4 molten glass supply process

Claims (6)

The step of heating and melting the glass raw material in the melting tank to generate molten glass, the step of transferring the molten glass flowing out from the outlet of the melting tank by a transfer pipe, and the step of transferring the molten glass from the transfer pipe. A method for manufacturing a glass article, comprising a step of performing a clarification treatment on the molten glass while the tubular portion of the clarification tank is filled.
The transfer pipe comprises an upstream end connected to the melting tank and a downstream end connected to the tubular portion.
A method for manufacturing a glass article, wherein the transfer pipe is connected to the tubular portion so that the top of the inner surface at the downstream end thereof coincides with the top of the inner surface of the tubular portion. In the transfer pipe, the top of the inner surface at the upstream end coincides with the top of the inner surface of the outlet, and the bottom of the inner surface at the upstream end coincides with the bottom of the inner surface of the outlet. The method for manufacturing a glass article according to claim 1, which is connected to a melting tank. The method for manufacturing a glass article according to claim 1 or 2, wherein the transfer pipe is connected to the tubular portion so that the bottom portion of the inner surface at the downstream end portion coincides with the bottom portion of the inner surface of the tubular portion. The method for manufacturing a glass article according to claim 3, wherein the transfer pipe includes an enlarged diameter portion whose inner diameter gradually increases toward the downstream end portion. The transfer pipe is configured in a straight tubular shape.
The method for manufacturing a glass article according to claim 1 or 2, wherein the transfer pipe is connected to the tubular portion so that the bottom of the inner surface at the downstream end portion is higher than the bottom of the inner surface of the tubular portion. The method for manufacturing a glass article according to any one of claims 1 to 5, further comprising a step of heating the transfer tube and the tubular portion in a separated state.

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