Method for manufacturing a glass article

Abstract

A method of manufacturing a glass article, when a glass article is manufactured using a state adjusting tank (4) that adjusts a state of molten glass (2), a forming body (7) that forms a glass ribbon (6) from the molten glass (2), and a supply pipe (5) that supplies the molten glass (2), the method is configured as follows: the supply pipe (5) including a small-diameter pipe (5a) and a large-diameter pipe (5b) is used, the two pipes (5a, 5b) are connected in a state in which a gap is formed between an outer peripheral surface of the small-diameter pipe (5a) and an inner peripheral surface of the large-diameter pipe (5b), and as a preparation process for starting the forming of the glass ribbon (6), a connection process that connects the three (4, 5, 7) and a temperature increasing process that increases the temperature of the three (4, 5, 7) are included, and in the method of manufacturing the glass article, the connection process is performed before completion of the temperature increasing process.

Description

TECHNICAL FIELD

[0001] The present application relates to a manufacturing method of a glass article. BACKGROUND

[0002] As one of processes for manufacturing a glass article such as a glass sheet, a glass roll, a process of forming a glass ribbon which is a source of the glass article by utilizing a down-draw overflow method is known. In this process, at the time of forming the glass ribbon, a condition adjustment tank, a supply pipe, and a forming body are used in a state where they are arranged in order from an upstream side of a flow of molten glass.

[0003] The condition adjustment tank adjusts a condition (viscosity, flow rate) of the molten glass which flows into the tank and causes the molten glass to flow out of the tank. The molten glass which flows out of the condition adjustment tank to the outside of the tank is supplied to the forming body through the supply pipe. And, the molten glass which is supplied to the forming body is formed into the glass ribbon.

[0004] The supply pipe includes a small-diameter pipe which is arranged oppositely on the upstream side and connected to the condition adjustment tank, and a large-diameter pipe which is arranged oppositely on the downstream side and connected to the forming body. The two pipes are joined in a state where the downstream end of the small-diameter pipe is housed in the upstream end of the large-diameter pipe and a gap is formed between the outer peripheral surface of the small-diameter pipe and the inner peripheral surface of the large-diameter pipe.

[0005] However, at the time of starting the formation of the glass ribbon, as a preparation for this, it is necessary to connect the three of the condition adjustment tank, the supply pipe, and the forming body, and to raise the three to a state where the molten glass can be accepted. Here, in the patent document 1, a mode is disclosed where the small-diameter pipe (downpipe 130) is joined to the large-diameter pipe (injection pipe 132) after the raising is completed, and the condition adjustment tank (distribution tank 125), the supply pipe (downpipe 130 and injection pipe 132), and the forming body (isopipe 135) are connected.

[0006] PRIOR ART DOCUMENTS

[0007] PATENT DOCUMENTS

[0008] Patent document 1: Japanese Patent Application Laid-Open No. 2010-519166 SUMMARY

[0009] PROBLEMS TO BE SOLVED BY THE INVENTION

[0010] However, in the mode disclosed in the patent document 1, there is a problem which should be solved as described below.

[0011] That is, in this method, since the small-diameter tube and the large-diameter tube are connected after the temperature rising is completed, it is necessary to connect the two tubes in an environment at an extremely high temperature, and there is a problem that it is difficult to connect the two tubes with high precision. Therefore, there is a case that the outer peripheral surface of the small-diameter tube and the inner peripheral surface of the large-diameter tube, which should originally oppose each other with a gap therebetween, are erroneously contacted and the two tubes are fused due to this. As a result, for example, when the height position of the shaped body is adjusted, in a case where the relative positions of the small-diameter tube and the large-diameter tube are changed, a defective case such as breakage of platinum or platinum alloy constituting each tube occurs.

[0012] A technical problem to be solved in view of the above is to avoid fusion of the small-diameter tube connected to the state adjustment tank and the large-diameter tube connected to the shaped body when a glass ribbon is shaped by the overflow down-draw method in manufacturing a glass article.

[0013] A solution to the problem

[0014] A method of manufacturing a glass article for solving the above problem, when a glass article is manufactured using a state adjustment tank that adjusts a state of molten glass flowing into the tank and discharges the molten glass from the tank, a shaped body that shapes a glass ribbon from the molten glass supplied by the overflow down-draw method, and a supply tube that supplies the molten glass discharged from the state adjustment tank to the shaped body, is configured as follows: a supply tube including a small-diameter tube disposed on an upstream side in opposition to the state adjustment tank and connected to the state adjustment tank, and a large-diameter tube disposed on a downstream side in opposition to the shaped body and connected to the shaped body is used, the two tubes are connected in a state where a gap is formed between an outer peripheral surface of the small-diameter tube and an inner peripheral surface of the large-diameter tube, and as a preparation process for starting shaping of the glass ribbon, a connection process of connecting the state adjustment tank, the supply tube, and the shaped body, and a temperature rising process of rising the three to a state where the molten glass can be received, the method of manufacturing a glass article is characterized in that the connection process is performed before completion of the temperature rising process.

[0015] In the method, the connection process of connecting the state adjustment tank, the supply tube, and the shaped body is performed before completion of the temperature rising process of rising the three to a state where the glass ribbon can be shaped. Therefore, when the three are connected, it is not necessary to connect the small-diameter tube and the large-diameter tube in an environment at a high temperature. Thus, workability can be greatly improved, and the small-diameter tube and the large-diameter tube can be connected with high precision. As a result, generation of a case where the outer peripheral surface of the small-diameter tube and the inner peripheral surface of the large-diameter tube are erroneously contacted and the two tubes are fused due to this is avoided.

[0016] In the above method, it is preferable that the temperature rising process is performed in a state where a molten glass flow path in the state adjustment tank is blocked by a blocking member.

[0017] The blocking member blocks the flow path of the molten glass, so that a gas flow of high-temperature gas that passes through the state adjustment tank from the forming body and the supply tube side to the upstream side is less likely to occur. Thus, oxidation of the state adjustment tank and the supply tube can be reduced, and temperature reduction of the state adjustment tank, the supply tube, and the forming body can be prevented.

[0018] In the method described above, it is preferable that the preparation step further includes a linking step of linking the state adjustment tank to a transfer device for transferring the molten glass to the state adjustment tank after the execution of the temperature increasing step, the linking step being executed in a state where the flow path of the molten glass in the state adjustment tank is blocked by the blocking member.

[0019] The blocking member blocks the flow path of the molten glass, so that a gas flow of high-temperature gas that passes through the state adjustment tank from the forming body and the supply tube side to the upstream side is less likely to occur. Thus, in the linking step, oxidation of the state adjustment tank and the supply tube can be reduced, and temperature reduction of the state adjustment tank, the supply tube, and the forming body can be prevented.

[0020] In the method described above, it is preferable that a throttle portion that gradually narrows in flow path cross-sectional area as it approaches the downstream side of the flow path of the molten glass is provided at the bottom of the state adjustment tank, and the blocking member is provided with a tip end portion that is tapered in shape in imitation of the shape of the throttle portion, and the flow path of the molten glass is blocked by disposing the tip end portion of the blocking member in the throttle portion.

[0021] In this way, on the basis that the throttle portion is shaped so as to gradually narrow in flow path cross-sectional area as it approaches the downstream side of the flow path of the molten glass, the tip end portion of the blocking member is tapered in shape in imitation of the shape of the throttle portion, so the flow path of the molten glass can be blocked simply and effectively using the blocking member.

[0022] In the method described above, it is preferable that a top end opening for inserting the blocking member into the state adjustment tank is provided at the top end portion of the state adjustment tank, and the top end opening is blocked in the execution of the temperature increasing step.

[0023] In this way, in the execution of the temperature increasing step, the top end opening of the state adjustment tank is blocked, so the temperature increase of the state adjustment tank can be performed efficiently.

[0024] In the method described above, it is preferable that, in the execution of the temperature increasing step, a flow inlet for causing the molten glass to flow into the state adjustment tank is blocked.

[0025] In this way, in the execution of the temperature increasing step, the flow inlet of the state adjustment tank is blocked, so the temperature increase of the state adjustment tank can be performed more efficiently.

[0026] In the method described above, it is preferable that the temperature increasing step is executed in a state where an opening and closing body disposed below the forming body closes a conveyance path for conveying the glass ribbon.

[0027] By using an opening and closing mechanism to shut off the transport path, the localized temperature drop of the molded body (especially the temperature at the lower end of the molded body) caused by the rising gas along the transport path can be suppressed. Therefore, structural defects (damage, cracks, etc.) in the molded body due to thermal shock can be avoided.

[0028] Invention Effects

[0029] According to the glass article manufacturing method of the present invention, when manufacturing glass articles using the overflow pull-down method to form glass strips, the welding of the small-diameter pipe connected to the condition adjustment groove and the large-diameter pipe connected to the forming body can be avoided. Attached Figure Description

[0030] Figure 1 This is a partial cross-sectional view showing the manufacturing apparatus used in a method of manufacturing glass articles.

[0031] Figure 2 This is a partial cross-sectional view showing the joining process in the manufacturing method of glass articles.

[0032] Figure 3 This is a partial cross-sectional view showing the heating process in the manufacturing method of glass articles.

[0033] Figure 4 This is a partial cross-sectional view showing the connecting process in the manufacturing method of glass articles.

[0034] Figure 5 This is a partial cross-sectional view showing the storage process in the manufacturing method of glass articles.

[0035] Figure 6 This is a partial cross-sectional view showing the feeding process in the manufacturing method of glass articles.

[0036] Figure 7 It is a partial cross-sectional view showing the manufacturing process of glass articles. Detailed Implementation

[0037] Hereinafter, the method for manufacturing the glass article according to the embodiments will be described with reference to the accompanying drawings. It should be noted that, unless otherwise specified, "platinum" in the following description can refer to any of pure platinum, platinum alloys (platinum-rhodium, etc.), or reinforced platinum (platinum containing zirconium oxide, etc.). First, the manufacturing apparatus used in this manufacturing method will be described.

[0038] like Figure 1As shown, the manufacturing apparatus 1 is provided with, in order from the upstream side of the flow of the molten glass 2, a transfer apparatus 3 for transferring the molten glass 2, a state adjustment tank 4 for adjusting the state of the molten glass 2, a supply pipe 5 for supplying the molten glass 2, and a forming body 7 for forming a glass ribbon 6 as a source of the glass article from the molten glass 2.

[0039] The transfer apparatus 3 has a function of transferring the molten glass 2, which has passed through a fining tank (tank for defoaming) and a stirring tank (tank for homogenization) in order after being generated from a glass raw material by a melting furnace, to the state adjustment tank 4. In other words, the manufacturing apparatus 1 of the present embodiment is provided with a melting furnace, a fining tank, a stirring tank, and the like. Note that, in the present embodiment, only a transfer pipe 3a disposed at the most downstream side in the transfer apparatus 3 is illustrated. The transfer pipe 3a can be connected to and disconnected from the state adjustment tank 4. The transfer pipe 3a is composed of platinum. Figure 1

[0040] The state adjustment tank 4 has a function of adjusting the state (for example, viscosity, flow rate) of the molten glass 2 flowing into the tank and causing the molten glass 2 to flow out of the tank. The state adjustment tank 4 is provided with a main body portion 4a, an inflow portion 4b connected to the side of the main body portion 4a, and a throttle portion 4c connected to the lower side of the main body portion 4a. The main body portion 4a, the inflow portion 4b, and the throttle portion 4c are each composed of platinum and can be electrically heated.

[0041] The inflow portion 4b has an inflow port 4x for causing the molten glass 2 to flow into the state adjustment tank 4 at the upstream end thereof. The inflow port 4x can be blocked in a state in which the connection to the transfer pipe 3a is disconnected.

[0042] The throttle portion 4c is a portion corresponding to the bottom of the state adjustment tank 4. The throttle portion 4c has a shape in which the flow path cross-sectional area gradually decreases toward the downstream side (in the present embodiment, the lower side) of the molten glass flow path inside the state adjustment tank 4. The throttle portion 4c has an outflow port 4y for causing the molten glass 2 to flow out of the state adjustment tank 4 at the downstream end thereof.

[0043] The main body portion 4a has a top end portion 4aa in which a top end opening 4ax is formed. The needle 8 (block member) described later can be inserted into the state adjustment tank 4 through the top end opening 4ax. The top end opening 4ax is blocked by a lid 9 formed of a refractory material whose surface is covered with platinum. The lid 9 has a through hole through which the needle 8 penetrates. The needle 8 has a front end portion 8a in which the front end is tapered in imitation of the shape of the throttle portion 4c and is movable in the up-down direction. Thus, in the present embodiment, as shown by the double-dotted line, when the needle 8 is moved to the lower limit position and the front end portion 8a is disposed at the throttle portion 4c, the molten glass flow path inside the state adjustment tank 4 becomes a blocked state. Note that, in the present embodiment, the needle 8 is composed of platinum. Figure 1 ​​

[0044] The supply pipe 5 has a function of supplying the molten glass 2, which has flown out from the state adjustment tank 4, to the forming body 7. The supply pipe 5 includes a small-diameter pipe 5a disposed on the upstream side opposite to the state adjustment tank 4 and a large-diameter pipe 5b disposed on the downstream side opposite to the forming body 7. Note that, in the present embodiment, both the small-diameter pipe 5a and the large-diameter pipe 5b are composed of platinum and can be electrically heated. Also, in the present embodiment, the thermal expansion rates of the two pipes 5a and 5b are the same.

[0045] The small-diameter pipe 5a extends linearly in the up-down direction. In contrast, the large-diameter pipe 5b is bent in order to change the flow direction of the molten glass 2. The two pipes 5a and 5b are joined in a state in which the downstream end of the small-diameter pipe 5a is housed in the upstream end of the large-diameter pipe 5b. Thus, the downstream end of the small-diameter pipe 5a and the upstream end of the large-diameter pipe 5b form a double-pipe structure, and a gap is formed between the outer peripheral surface of the small-diameter pipe 5a and the inner peripheral surface of the large-diameter pipe 5b. The width of the gap is, for example, 5 mm to 50 mm. The gap is blocked by a sealing member such as a lid 10 provided at the upstream end of the large-diameter pipe 5b. The amount of overlap (length of overlap in the up-down direction) of the downstream end of the small-diameter pipe 5a and the upstream end of the large-diameter pipe 5b can be changed at the time of adjustment of the height position of the forming body. The two pipes 5a and 5b are each housed in a housing, and the relative positions of the two pipes 5a and 5b are determined in conjunction with the fixing of each housing.

[0046] The forming body 7 has a function of forming a glass ribbon 6 from the supplied molten glass 2 by the overflow down-draw method. The forming body 7 is housed inside a forming chamber 11 and is surrounded by the wall portion (side wall, top end wall) of the forming chamber 11. The forming body 7 is heated by a heating mechanism such as a heater inside the forming chamber 11. An annealing furnace (not shown) for annealing the glass ribbon 6 is disposed at the lower stage of the forming chamber 11, and a cooling chamber (not shown) for cooling the glass ribbon 6 to room temperature is disposed at the lower stage of the annealing furnace. The lower portion of the forming chamber 11, the annealing furnace, and the cooling chamber constitute a conveyance path for conveying the glass ribbon 6.

[0047] The forming chamber 11 has an opening and closing body 11a for opening and closing the forming chamber 11 (conveyance path) below the forming body 7. The opening and closing body 11a is composed of a pair of plate-shaped members having heat resistance and can be separated from each other along a direction perpendicular to the paper surface in the Figure 1 Note that, the annealing furnace or the cooling chamber can also have an opening and closing body.

[0048] Next, a method for manufacturing a glass article using the manufacturing apparatus 1 described above will be described. In the present manufacturing method, as a preparation process for starting the formation of the glass ribbon 6 that is the source of the glass article, a connection process ( Figure 2 ), a temperature increase process ( Figure 3 ), a joining processFigure 4 Storage process Figure 5 ), supply process ( Figure 6 ).

[0049] exist Figure 2 In the connection process shown, the state adjustment groove 4, the supply pipe 5, and the forming body 7 are connected. At this time, the small-diameter pipe 5a and the large-diameter pipe 5b included in the supply pipe 5 are connected in a precisely positioned state, with a gap formed between the outer circumferential surface of the small-diameter pipe 5a and the inner circumferential surface of the large-diameter pipe 5b. Specifically, the two pipes 5a and 5b are connected with their centerlines aligned at the downstream end of the small-diameter pipe 5a and the upstream end of the large-diameter pipe 5b. However, this is not a limitation; as long as a gap is formed between the outer circumferential surface of the small-diameter pipe 5a and the inner circumferential surface of the large-diameter pipe 5b, the centerlines of the pipes may not be aligned. In this embodiment, the connection of components 4, 5, and 7 is performed at room temperature (e.g., 20°C ± 15°C).

[0050] Furthermore, in the joining process, as preparation for the subsequent heating process, the following steps (A) to (C) are performed: (A) By placing the tip 8a of the needle 8 on the throttling section 4c of the state adjustment tank 4, the flow path of the molten glass in the state adjustment tank 4 is blocked. (B) The inlet 4x of the state adjustment tank 4 is sealed with a cover 12 made of heat-insulating material. (C) The forming chamber 11 (transport path) is closed using an opening / closing body 11a provided in the forming chamber 11. It should be noted that the transport path can also be closed using an opening / closing body provided in an annealing furnace or a cooling chamber.

[0051] exist Figure 3 In the heating process shown, the conditioning tank 4, the supply pipe 5, and the forming body 7 are heated until they are ready to accept molten glass 2. For example, the three components 4, 5, and 7 are heated from room temperature to 1000°C to 1300°C. At this time, the flow path of the molten glass in the conditioning tank 4 is blocked by the front end 8a of the needle 8, thereby easily preventing heat from escaping from the forming body 7 and the supply pipe 5 side to the conditioning tank 4 side. Therefore, the forming body 7 can be heated while preventing rapid temperature changes, and structural defects (defects, cracks, etc.) in the forming body 7 due to thermal shock can be avoided.

[0052] exist Figure 4In the connection process shown, the state adjustment tank 4 is connected to the transfer device 3. Specifically, after the lid 12 that blocks the flow inlet 4x of the state adjustment tank 4 until the stage at which the temperature elevation process is completed is removed, the transfer pipe 3a is connected to the flow inlet 4x. At this time, as in the execution of the temperature elevation process, the state in which the molten glass flow path inside the state adjustment tank 4 is blocked by the front end portion 8a of the needle 8 is attained. Thereby, the gas flow of high-temperature gas that passes through the state adjustment tank 4 from the shaped body 7 and the supply pipe 5 side to the upstream side does not occur, and the temperature decrease of the shaped body 7 and the supply pipe 5 can be prevented.

[0053] In Figure 5 In the storage process shown, the molten glass 2 is caused to flow into the state adjustment tank 4 from the transfer pipe 3a, and the molten glass 2 is intercepted at a position upstream of the front end portion 8a of the needle 8 disposed at the throttle portion 4c. Thereby, the molten glass 2 is stored in the state adjustment tank 4. At this time, the adjustment of the viscosity of the molten glass 2 is also simultaneously performed.

[0054] In Figure 6 In the supply process shown, the front end portion 8a of the needle 8 disposed at the throttle portion 4c of the state adjustment tank 4 is moved upward until the stage at which the storage process is completed. Thereby, the supply of the molten glass 2 from the state adjustment tank 4 to the shaped body 7 through the supply pipe 5 (the small-diameter pipe 5a and the large-diameter pipe 5b) is started. At this time, the path of the gas at a high temperature from the shaped body 7 and the supply pipe 5 side to the upstream side is blocked by the action of the molten glass 2 that flows from the throttle portion 4c to the small-diameter pipe 5a. Thus, the temperature decrease of the shaped body 7 and the supply pipe 5 can be prevented.

[0055] After the supply of the molten glass 2 to the shaped body 7 is started, the opening and closing body 11a provided at the forming chamber 11 is opened. Thereby, the path for moving the glass ribbon 6 that flows down from the shaped body 7 from the inside of the forming chamber 11 to the outside is opened. In the viewpoint of reliably avoiding the occurrence of structural defects (defects, cracks, etc.) in the shaped body 7 due to thermal shock, it is preferable to open the opening and closing body 11a at the stage at which the shaped body 7 is covered with the molten glass 2 after the supply of the molten glass 2 to the shaped body 7 is started, as shown in the drawing. After that, the glass ribbon 6 that has been shaped is cut in the width direction to cut out a glass sheet from the glass ribbon 6 or to wind the glass ribbon 6 in a roll shape to become a glass roll, and thus a glass sheet or a glass roll as a glass article is manufactured. Figure 7

[0056] Hereinafter, the main effects and advantages of the above-described glass article manufacturing method will be described.

[0057] ​In the manufacturing method described above, the connecting process is performed before the execution of the temperature increasing process. Therefore, when connecting the three of the state adjusting groove 4, the supply pipe 5, and the shaped body 7, it is not necessary to join the small-diameter pipe 5a and the large-diameter pipe 5b in a high-temperature environment. Thus, the small-diameter pipe 5a and the large-diameter pipe 5b can be joined with high precision. As a result, it is possible to avoid the occurrence of a situation in which the outer peripheral surface of the small-diameter pipe 5a and the inner peripheral surface of the large-diameter pipe 5b are miscontacted and the two pipes 5a, 5b are fused due to this.

[0058] Here, as a modification of the embodiment described above, the following manner can also be employed. That is, in the embodiment described above, the connecting process is performed at normal temperature before the execution of the temperature increasing process, but as long as there is no obstacle in the accurate joining of the small-diameter pipe 5a and the large-diameter pipe 5b, the connecting process can also be performed midway through the temperature increasing process (at a temperature higher than normal temperature). In this case, the temperature of the small-diameter pipe 5a and the large-diameter pipe 5b in the connecting process is preferably 200°C or lower, more preferably 100°C or lower, and most preferably 50°C or lower.

[0059] Explanation of Reference Numerals

[0060] 2 molten glass

[0061] 3 transfer device

[0062] 4 state adjusting groove

[0063] 4aa top end portion

[0064] 4ax top end opening

[0065] 4c throttle portion

[0066] 4x flow inlet

[0067] 5 supply pipe

[0068] 5a small-diameter pipe

[0069] 5b large-diameter pipe

[0070] 6 glass ribbon

[0071] 7 shaped body

[0072] 8 needle (blocking member)

[0073] 8a front end portion

Claims

1. A method for manufacturing glass articles, When manufacturing glass articles using a state-adjusting tank that adjusts the state of molten glass flowing into the tank and causes the molten glass to flow out of the tank, a forming body that forms a glass ribbon from molten glass supplied by an overflow pull-down method, and a supply pipe that supplies molten glass flowing out of the state-adjusting tank to the forming body. The structure is configured as follows: a supply pipe comprising a small-diameter pipe disposed opposite to the upstream side and connected to the state adjustment groove, and a large-diameter pipe disposed opposite to the downstream side and connected to the forming body, wherein the two pipes are connected with a gap formed between the outer circumferential surface of the small-diameter pipe and the inner circumferential surface of the large-diameter pipe, and... As a preparatory step for initiating the forming of the glass ribbon, the process includes a connection step of connecting the state adjustment tank, the supply pipe, and the forming body, and a heating step of heating the three components until they are in a state that can accept the molten glass. The method for manufacturing the glass article is characterized by, The connection process is performed before the heating process is completed. The heating process is performed while the flow path of the molten glass in the state adjustment tank is blocked by the blocking component.

2. A method for manufacturing glass articles, When manufacturing glass articles using a state-adjusting tank that adjusts the state of molten glass flowing into the tank and causes the molten glass to flow out of the tank, a forming body that forms a glass ribbon from molten glass supplied by an overflow pull-down method, and a supply pipe that supplies molten glass flowing out of the state-adjusting tank to the forming body. The structure is configured as follows: a supply pipe comprising a small-diameter pipe disposed opposite to the upstream side and connected to the state adjustment groove, and a large-diameter pipe disposed opposite to the downstream side and connected to the forming body, wherein the two pipes are connected with a gap formed between the outer circumferential surface of the small-diameter pipe and the inner circumferential surface of the large-diameter pipe, and... As a preparatory step for initiating the forming of the glass ribbon, the process includes a connection step of connecting the state adjustment tank, the supply pipe, and the forming body, and a heating step of heating the three components until they are in a state that can accept the molten glass. The method for manufacturing the glass article is characterized by, The connection process is performed before the heating process is completed. As part of the preparation process, the process further includes a connection step after the heating process, whereby the conditioning tank is connected to a transfer device for transferring molten glass into the conditioning tank. The connecting process is performed while the flow path of the molten glass in the state adjustment tank is blocked by the blocking component.

3. The method for manufacturing glass articles according to claim 1 or 2, characterized in that, A throttling section is provided at the bottom of the state adjustment tank, where the cross-sectional area of ​​the flow path gradually decreases as it moves downstream of the molten glass flow path. The blocking member has a front end portion that tapers to the shape of the throttling section. The flow path of the molten glass is blocked by positioning the front end of the blocking member at the throttling section.

4. The method for manufacturing glass articles according to claim 1 or 2, characterized in that, A top opening is provided at the top of the state adjustment groove for inserting the blocking member into the state adjustment groove. During the heating process, the top opening is sealed.

5. A method for manufacturing a glass article, When manufacturing glass articles using a state-adjusting tank that adjusts the state of molten glass flowing into the tank and causes the molten glass to flow out of the tank, a forming body that forms a glass ribbon from molten glass supplied by an overflow pull-down method, and a supply pipe that supplies molten glass flowing out of the state-adjusting tank to the forming body. The structure is configured as follows: a supply pipe comprising a small-diameter pipe disposed opposite to the upstream side and connected to the state adjustment groove, and a large-diameter pipe disposed opposite to the downstream side and connected to the forming body, wherein the two pipes are connected with a gap formed between the outer circumferential surface of the small-diameter pipe and the inner circumferential surface of the large-diameter pipe, and... As a preparatory step for initiating the forming of the glass ribbon, the process includes a connection step of connecting the state adjustment tank, the supply pipe, and the forming body, and a heating step of heating the three components until they are in a state that can accept the molten glass. The method for manufacturing the glass article is characterized by, The connection process is performed before the heating process is completed. During the heating process, the inlet for allowing molten glass to flow into the conditioning tank is blocked.

6. A method for manufacturing glass articles, When manufacturing glass articles using a state-adjusting tank that adjusts the state of molten glass flowing into the tank and causes the molten glass to flow out of the tank, a forming body that forms a glass ribbon from molten glass supplied by an overflow pull-down method, and a supply pipe that supplies molten glass flowing out of the state-adjusting tank to the forming body. The structure is configured as follows: a supply pipe comprising a small-diameter pipe disposed opposite to the upstream side and connected to the state adjustment groove, and a large-diameter pipe disposed opposite to the downstream side and connected to the forming body, wherein the two pipes are connected with a gap formed between the outer circumferential surface of the small-diameter pipe and the inner circumferential surface of the large-diameter pipe, and... As a preparatory step for initiating the forming of the glass ribbon, the process includes a connection step of connecting the state adjustment tank, the supply pipe, and the forming body, and a heating step of heating the three components until they are in a state that can accept the molten glass. The method for manufacturing the glass article is characterized by, The connection process is performed before the heating process is completed. The heating process is performed while the transport path for transporting the glass strip is closed using an opening and closing body located below the molded body.

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