Glass molding device, method of manufacturing glass article, and edge roller

Abstract

To obtain a glass ribbon with sufficient widthwise length while restraining devitrification of molten glass, as well as avoiding a layout problem and a device enlargement problem.SOLUTION: A glass molding device 1 for molding a glass ribbon Gr from molten glass Gm by a down-draw method comprises: a compact 2; and an edge roller 3 nipping a widthwise end Gra of the glass ribbon Gr dropping from the compact 2. The edge roller 3 comprises: a roller part 3a in contact with the glass ribbon Gr; a shaft part 3b mounted to the roller part 3a; and a flow path 3bx provided inside the shaft part 3b and supplying / discharging a refrigerant to / from a cooling space 3ax inside the roller part 3a. The shaft part 3b is provided with a heat insulation part 7.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a glass forming apparatus for forming a glass ribbon from molten glass by a down-draw method, a method for manufacturing a glass article using the same, and an edge roller.

Background Art

[0002] As is well known, in the process of manufacturing a glass plate or a glass roll, a glass ribbon is formed from molten glass using a forming body. As an example, Patent Document 1 discloses a glass forming apparatus configured to form a glass ribbon from molten glass by an overflow down-draw method.

[0003] Specifically, the glass forming apparatus disclosed in the same document forms a glass ribbon by allowing molten glass to overflow from a groove formed at the top of a wedge-shaped forming body, flowing the molten glass down along both side surfaces of the forming body, and then fusing the molten glass at the lower end of the forming body. In this case, the widthwise end portions of the glass ribbon descending from the forming body are clamped by edge rollers in which a refrigerant circulates inside.

[0004] In addition to such a configuration, the glass forming apparatus disclosed in the same document arranges a heat shield above the edge rollers and below the forming body in order to reduce heat loss from an edge guide (edge director in the same document) attached to the widthwise end portion of the forming body to the edge rollers.

[0005] By arranging the heat shield in this way, it becomes difficult for the edge guide of the forming body to be unduly cooled by the edge rollers, so it is expected to suppress devitrification of the molten glass that may occur around the edge guide at the lower end portion of the forming body.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] However, in the glass forming apparatus disclosed in the same document, since a space for arranging the heat shield is required, the vertical separation distance between the formed body and the edge roller becomes long. In this case, the glass ribbon immediately after descending from the formed body increases the amount of shrinkage in the width direction as it moves downward.

[0008] Therefore, when the above separation distance is long, the edge roller has to sandwich the glass ribbon at a position where the width direction length of the glass ribbon becomes unduly short, making it difficult to obtain a glass ribbon with a sufficient width direction length after forming.

[0009] Furthermore, in the glass forming apparatus disclosed in the same document, due to the rotation of the edge roller, it is necessary to separate the heat shield from the edge roller, which causes problems in layout and an increase in the size of the apparatus.

[0010] From the above viewpoints, an object of the present invention is to obtain a glass ribbon with a sufficient width direction length while suppressing devitrification of molten glass and avoiding problems in layout and an increase in the size of the apparatus.

Means for Solving the Problems

[0011] (1) The first aspect of the present invention devised to solve the above problems is a glass forming apparatus for forming a glass ribbon from molten glass by the down-draw method, comprising a forming body and edge rollers for sandwiching the widthwise ends of the glass ribbon descending from the forming body. The edge rollers include a roller portion that contacts the glass ribbon, a shaft portion to which the roller portion is attached, and a flow path provided inside the shaft portion for supplying and discharging a refrigerant to and from a cooling space inside the roller portion. The shaft portion is characterized by including a heat insulating portion. Here, the edge roller means a roller disposed at the uppermost stage among a plurality of upper and lower stages of rollers that sandwich the widthwise ends of the glass ribbon descending from the forming body.

[0012] According to such a configuration, since the shaft portion of the edge roller includes a heat insulating portion, the following operational effects can be obtained. First, devitrification that may occur at the widthwise ends of the molten glass at the lower end portion of the forming body is suppressed. Specifically, although the shaft portion of the edge roller is not in contact with the glass ribbon, its temperature decreases significantly because it is cooled by the refrigerant. Therefore, the widthwise ends of the molten glass flowing down the forming body are cooled by the shaft portion at the lower end portion of the forming body, making devitrification likely to occur. According to the configuration here, by providing the shaft portion with a heat insulating portion, such devitrification of the molten glass can be suppressed. Second, the vertical separation distance between the forming body and the edge roller can be shortened, so that the glass ribbon can be sandwiched by the edge roller at a position where the amount of shrinkage in the width direction of the glass ribbon descending from the forming body is small. Therefore, a glass ribbon with a sufficient widthwise length can be obtained. Third, since there is no need to separately arrange other heat insulating members between the forming body and the edge roller, problems related to layout and enlargement of the apparatus do not occur.

[0013] (2) In the configuration of (1) above, the heat insulating portion may be a heat insulating layer provided between the outer peripheral surface of the shaft portion and the flow path.

[0014] By doing so, compared with the case where the heat insulation layer is provided on the outer peripheral side of the outer peripheral surface of the shaft portion, the shaft portion can be miniaturized, and deterioration, wear, etc. of the heat insulation layer can be reduced.

[0015] (3) In the configuration of (2) above, the heat insulation layer may be configured by storing gas in a space formed between the outer peripheral surface of the shaft portion and the flow path.

[0016] By doing so, the configuration of the heat insulation layer is simplified, and the heat insulation effect can be obtained efficiently.

[0017] (4) In the configuration of (3) above, the gas may be air.

[0018] By doing so, while reducing the manufacturing cost of the heat insulation layer, the heat insulation effect can be obtained efficiently.

[0019] (5) In any of the configurations of (2) to (4) above, the heat insulation layer may have an elongated shape that is long in the axial direction in a cross section including the central axis of the shaft portion.

[0020] By doing so, since the heat insulation effect can be obtained in a wide area in the axial direction of the shaft portion, devitrification of the molten glass can be suppressed in a wide area in the width direction.

[0021] (6) In any of the configurations of (2) to (5) above, the heat insulation layer may be formed along a circle centered on its central axis in a cross section perpendicular to the central axis of the shaft portion.

[0022] By doing so, since a uniform heat insulation effect can be obtained in the circumferential direction of the shaft portion, devitrification of the molten glass can be further suppressed.

[0023] (7) In any of the configurations of (2) to (6) above, the radial separation distance between the heat insulation layer and the flow path may be shorter than the radial separation distance between the heat insulation layer and the outer peripheral surface of the shaft portion.

[0024] By doing so, further miniaturization of the heat insulation layer can be achieved, and the manufacturing cost can be further reduced.

[0025] (8) In any of the configurations of (2) to (7) above, the shaft portion is formed by joining a first portion located on the roller portion side in the axial direction and a second portion located on the side opposite to the roller portion side in the axial direction, and the heat insulation layer may be provided on the first portion.

[0026] By doing so, maintenance of the shaft portion can be easily performed, and the heat insulation layer is formed at an appropriate site in the axial direction of the shaft portion, that is, a site close to a site where devitrification of the molten glass flowing down the molded body is likely to occur. Therefore, devitrification of the molten glass can be effectively suppressed.

[0027] (9) In any of the configurations of (2) to (7) above, one axial end portion of the heat insulation layer may be located at the joint portion between the first portion and the second portion.

[0028] By doing so, maintenance of the heat insulation layer can be easily performed, and by providing a gap in the joint portion that communicates from the heat insulation layer to the flow path side or the outer peripheral side of the shaft portion, air or the like present in the heat insulation layer can be discharged, and rupture or explosion of the shaft portion in a high-temperature atmosphere can be prevented. In addition, the manufacturing cost of the heat insulation layer can be significantly reduced.

[0029] (10) In any of the configurations of (1) to (9) above, the heat insulation portion may extend along the width direction in the lower region of the width direction end portion of the molten glass flowing down the molded body.

[0030] By doing so, a sufficient and reliable heat insulation effect can be obtained with respect to a site where devitrification of the molten glass flowing down the molded body is likely to occur, that is, a peripheral site of the width direction end portion of the molten glass flowing down the lower end portion of the molded body.

[0031] (11) In any of the configurations (1) to (10) above, the molded body is used for molding a glass ribbon by the overflow down-draw method. An edge guide is attached to the widthwise end of the molded body, and the heat insulation part may extend along the width direction in the lower region of the edge guide.

[0032] In this way, devitrification of the molten glass caused by the shaft part cooling the edge guide is suppressed. Specifically, when the edge guide is cooled, devitrification is likely to occur around the location where the molten glass contacts the edge guide at the lower end of the molded body. According to the configuration here, since the cooling of the edge guide is suppressed by the heat insulation part provided in the shaft part, the occurrence of such devitrification is suppressed.

[0033] (12) In any of the configurations (1) to (11) above, a position adjustment mechanism for adjusting the vertical position of the edge roller may be provided.

[0034] In this way, without causing layout problems, the vertical position of the edge roller can be adjusted by the position adjustment mechanism. Moreover, when devitrification occurs in the molten glass flowing down the molded body, the occurrence of such devitrification can be suppressed by moving the edge roller downward by the position adjustment mechanism.

[0035] (13) In any of the configurations (1) to (12) above, the separation distance between the molded body and the shaft part may be 30 to 200 mm.

[0036] In this way, since the glass ribbon can be clamped by the edge roller at a position where the shrinkage amount in the width direction of the molten glass descending from the molded body is small, a glass ribbon with a sufficient widthwise length can be obtained.

[0037] (14) In any of the configurations (1) to (13) above, the heat insulation part may be provided on the outer peripheral surface of the shaft part.

[0038] By doing so, it is possible to obtain a heat insulation effect over a wide area of the shaft portion while preventing the enlargement of the shaft portion. In this case, as an example of providing a heat insulation portion on the outer peripheral surface of the shaft portion, it is possible to perform metal spraying on the outer peripheral surface of the shaft portion using a metal material having higher heat insulation properties than the material of the shaft portion.

[0039] (15) In any of the configurations (1) to (14) above, the flow path may include a supply path for supplying the refrigerant to the cooling space of the roller portion and a discharge path for discharging the supplied refrigerant.

[0040] By doing so, the refrigerant can be smoothly supplied and discharged inside the shaft portion and inside the roller portion.

[0041] (16) A second aspect of the present invention devised to solve the above problems is a method for manufacturing a glass article, characterized by comprising a forming step of forming a glass ribbon from molten glass using any of the glass forming apparatuses (1) to (15) above.

[0042] According to such a method, substantially the same operational effects as those of any of the glass forming apparatuses (1) to (15) above can be obtained.

[0043] (17) A third aspect of the present invention devised to solve the above problems is an edge roller used for sandwiching the widthwise ends of a glass ribbon when forming the glass ribbon from molten glass by the down-draw method, comprising a roller portion that contacts the glass ribbon, a shaft portion to which the roller portion is attached, and a flow path provided inside the shaft portion for supplying and discharging the refrigerant to and from the cooling space inside the roller portion, wherein the shaft portion is characterized by comprising a heat insulation portion.

[0044] If an edge roller having such a heat insulation portion is used in a glass forming apparatus for forming a glass ribbon from molten glass by the down-draw method, substantially the same operational effects as those of the configuration (1) above can be obtained.

Effects of the Invention

[0045] According to the present invention, while avoiding problems such as layout problems and enlargement of the apparatus, it is possible to obtain a glass ribbon having a sufficient length in the width direction while suppressing devitrification of the molten glass.

Brief Description of the Drawings

[0046]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0047] Hereinafter, a glass forming apparatus, an edge roller, and a method for manufacturing a glass article according to an embodiment of the present invention will be described with reference to the accompanying drawings. Note that the glass forming apparatus according to the following embodiment is used when forming a glass ribbon by the overflow down-draw method.

[0048] FIG. 1 is a front view showing a main part configuration of a glass forming apparatus 1 according to an embodiment of the present invention, and FIG. 2 is a perspective view showing a main part of the apparatus 1. In the description based on FIGS. 1 and 2, the A-A direction is described as the width direction (the same applies to FIG. 5 described later), and the B-B direction (see FIG. 2) is described as the thickness direction. Further, the main parts of the glass forming apparatus 1 shown in FIGS. 1 and 2 have the same configuration on both sides in the width direction and the same configuration on both sides in the thickness direction.

[0049] As shown in FIGS. 1 and 2, the glass forming apparatus 1 mainly includes a formed body 2, an edge roller 3, and an annealing roller 4.

[0050] Both side surfaces 2a existing on both sides in the thickness direction of the formed body 2 are each composed of a vertical surface portion 2aa and an inclined surface portion 2ab continuous with the lower end thereof. An overflow groove 2b extending in the width direction is formed at the top of the formed body 2. Edge guides 5 are respectively attached to both ends in the width direction of the formed body 2. The edge guide 5 restricts the outflow of the molten glass Gm to the outside in the width direction when the molten glass Gm overflowing from the overflow groove 2b of the formed body 2 flows down each of the both side surfaces 2a of the formed body 2. Therefore, both end portions Gma in the width direction of the molten glass Gm flowing down each of the both side surfaces 2a of the formed body 2 contact the edge guide 5. The edge guide 5 is formed of a metal plate such as platinum or a platinum alloy. The formed body 2 is formed of refractory bricks.

[0051] The edge roller 3 sandwiches both end portions Gra in the width direction of the glass ribbon Gr below the formed body 2. Specifically, both end portions Gra in the width direction of the glass ribbon Gr descending from the formed body 2 are respectively sandwiched by a pair of edge rollers 3. These edge rollers 3 are cantilever-supported and rotationally driven by a motor or the like in the direction of sending the glass ribbon Gr downward. These edge rollers 3 may be provided in a plurality of upper and lower stages (for example, two upper and lower stages). In the case of two upper and lower stages, it is preferable that the upper edge roller 3 is a driving roller and the lower edge roller 3 is a free roller.

[0052] The annealing roller 4 sandwiches both end portions Gra in the width direction of the glass ribbon Gr below the edge roller 3 and is provided in a plurality of upper and lower stages. Therefore, both end portions Gra in the width direction of the glass ribbon Gr are respectively sandwiched by a pair of annealing rollers 4 in a plurality of upper and lower stages. Most or all of these annealing rollers 4 are driving rollers for sending the glass ribbon Gr downward.

[0053] The configuration and the operational effects of the edge roller 3 will be described in detail below. In the case where a plurality of upper and lower stages of edge rollers 3 are provided, the configuration and the operational effects of the uppermost edge roller 3 will be described below.

[0054] FIG. 3 is a longitudinal front view showing the configuration of the edge roller 3, and FIG. 4 is a cross-sectional view taken along the line C-C of FIG. 3. As shown in FIG. 3, the edge roller 3 includes a roller portion 3a that contacts the glass ribbon Gr, and a shaft portion 3b to which the roller portion 3a is attached.

[0055] Inside the roller portion 3a, a cooling space 3ax for supplying and discharging a refrigerant is provided. Therefore, the roller portion 3a cools both end portions Gra in the width direction of the glass ribbon Gr, and acts to regulate the shrinkage in the width direction of the glass ribbon Gr. As the refrigerant, water or air is used.

[0056] In the present embodiment, the shaft portion 3b is divided into a first portion 3b1 located on the roller portion 3a side in the axial direction and a second portion 3b2 located on the side opposite to the roller portion 3a side in the axial direction, and is configured by joining the first portion 3b1 and the second portion 3b2. Both the first portion 3b1 and the second portion 3b2 are formed of heat-resistant steel, and it is preferable that the first portion 3b1 has higher heat resistance than the second portion 3b2.

[0057] Inside the shaft portion 3b, a flow path 3bx for supplying and discharging a refrigerant is provided. The flow path 3bx includes a supply path 3by for supplying the refrigerant to the cooling space 3ax of the roller portion 3a, and a discharge path 3bz for discharging the refrigerant supplied to the cooling space 3ax of the roller portion 3a. In the present embodiment, the supply path 3by is formed on the inner peripheral side of the supply pipe 6, and the discharge path 3bz is formed on the outer peripheral side of the supply pipe 6.

[0058] As a feature of this edge roller 3, the shaft portion 3b is provided with a heat insulation portion 7. The heat insulation portion 7 is a heat insulation layer provided between the outer peripheral surface 3ba of the shaft portion 3b and the flow path 3bx. The heat insulation layer 7 is configured by filling a gas into a space portion 3bb formed between the outer peripheral surface 3ba of the shaft portion 3b and the flow path 3bx. Air is used as the gas. For example, air at room temperature is supplied to the supply path 3by as a refrigerant.

[0059] The heat insulation layer 7 has an elongated shape that is long in the axial direction in the cross section shown in FIG. 3, that is, in the cross section including the central axis X of the shaft portion 3b. Further, the heat insulation layer 7 is formed along a circle centered on the central axis X in the cross section shown in FIG. 4, that is, in the cross section orthogonal to the central axis X of the shaft portion 3b. The axial length L1 of the heat insulation layer 7 is 20 to 300 mm, preferably 40 to 150 mm (see FIG. 3). Further, the radial length L2 of the heat insulation layer 7 is 0.1 to 20 mm, preferably 0.1 to 5 mm (see FIG. 4).

[0060] Furthermore, as shown in FIG. 3, the radial separation distance L3 between the heat insulation layer 7 and the flow path 3bx is shorter than the radial separation distance L4 between the heat insulation layer 7 and the outer peripheral surface 3ba of the shaft portion 3b. Also, the heat insulation layer 7 is provided in the first portion 3b1 of the shaft portion 3b. And one axial end portion of the heat insulation layer 7 is located at the joint portion 3bc between the first portion 3b1 and the second portion 3b2. In other words, one axial end portion of the heat insulation layer 7 opens to the joint surface 3bd of the first portion 3b1. In this case, the first portion 3b1 and the second portion 3b2 are fixed only at their outer peripheral side ends by welding or the like. Therefore, at their joint portion 3bc, a fixing portion 3be is provided only at the outer peripheral side end. That is, the space portion 3bb is not sealed. Therefore, the air filled in the space portion 3bb can escape to the flow path 3bx (discharge path 3bz) through the gap on the inner peripheral side of the fixing portion 3be at the joint portion 3bc.

[0061] Also, as shown in FIG. 5, the heat insulating layer 7 extends along the width direction in the lower region E of the edge guide 5 attached to the molded body 2. Specifically, the heat insulating layer 7 includes the lower region E of the edge guide 5 in the width direction and protrudes from both sides in the width direction from the lower region E. Further, the heat insulating layer 7 extends along the width direction in the lower region F of the width direction end Gma of the molten glass Gm flowing down the side surface 2a of the molded body 2. Specifically, the heat insulating layer 7 includes the lower region F of the width direction end Gma of the molten glass Gm in the width direction and protrudes from both sides in the width direction from the lower region F. In this case, the separation distance L5 between the molded body 2 and the shaft portion 3b of the edge roller 3 is preferably 30 to 200 mm, and more preferably 30 to 50 mm.

[0062] Furthermore, the edge roller 3 is held so that its vertical position can be adjusted. More specifically, as shown in FIG. 6, the edge roller 3 is configured such that its vertical position is adjusted by a position adjusting mechanism 8. This position adjusting mechanism 8 holds a support portion 9 that supports the edge roller 3 on a moving base 10 and moves the moving base 10 up and down by a driving device 11. The support portion 9 is composed of a bearing that rotatably holds the axial end of the shaft portion 3b of the edge roller 3, a motor that applies a rotational driving force to the shaft portion 3b, and the like. In the illustrated example, a fluid pressure cylinder 11a such as a plurality of air cylinders is used as the driving device 11, but other driving devices such as a ball screw mechanism or a device using a table that can slide up and down may also be used. In this case, the driving device 11 is installed on a support member 12 such as a member constituting a furnace wall surrounding the molded body 2 or a member fixed to the furnace wall.

[0063] According to the glass forming apparatus 1 having the above configuration, the following operational effects can be obtained.

[0064] Since the shaft portion 3b of the edge roller 3 is provided with the heat insulation portion 7, devitrification of the molten glass Gm can be efficiently suppressed. More specifically, although the shaft portion 3b of the edge roller 3 is not in contact with the glass ribbon Gr, its temperature drops significantly because it is cooled by the refrigerant. Therefore, the widthwise end portion Gma of the molten glass Gm flowing down the molded body 2 is cooled by the shaft portion 3b at the lower end portion of the molded body 2, and devitrification is likely to occur. On the other hand, if the shaft portion 3b is provided with the heat insulation portion 7, such devitrification of the molten glass Gm can be suppressed.

[0065] Since the shaft portion 3b of the edge roller 3 is provided with the heat insulation portion 7, there is no need to separately arrange other heat insulation members between the edge roller 3 and the molded body 2, and the vertical separation distance between the edge roller 3 and the molded body 2 can be shortened. Therefore, the glass ribbon Gr can be clamped by the edge roller 3 at a position where the shrinkage amount in the width direction of the glass ribbon Gr descending from the molded body 2 is small. As a result, a glass ribbon Gr with a sufficient widthwise length can be obtained. In addition, since there is no need to separately arrange other heat insulation members between the edge roller 3 and the molded body 2, problems with the layout and the enlargement of the glass forming apparatus 1 do not occur.

[0066] Since the heat insulation portion 7 is a heat insulation layer provided between the outer peripheral surface 3ba of the shaft portion 3b and the flow path 3bx, downsizing of the heat insulation layer 7 can be achieved, and the manufacturing cost can be reduced. More specifically, this type of heat insulation layer 7 may be provided on the outer peripheral side of the outer peripheral surface 3ba of the shaft portion 3b, but compared with the case of doing so, downsizing of the heat insulation layer 7 can be achieved, and the manufacturing cost can be reduced.

[0067] Since the heat insulation layer 7 is configured by filling air into the space portion 3bb formed between the outer peripheral surface 3ba of the shaft portion 3b and the flow path 3bx, compared with the case where the heat insulation layer 7 is provided on the outer peripheral side of the outer peripheral surface 3ba of the shaft portion 3b, the shaft portion 3b can be downsized, and deterioration, wear, etc. of the heat insulation layer 7 can be reduced.

[0068] Since the heat insulation layer 7 has an elongated shape extending along the axial direction in a cross section including the central axis X of the shaft portion 3b, a heat insulation effect can be obtained in a wide area in the axial direction of the shaft portion 3b, and devitrification of the molten glass Gm can be suppressed in a wide area in the radial direction.

[0069] Since the heat insulation layer 7 is formed along a circle centered on the central axis X in a cross section orthogonal to the central axis X of the shaft portion 3b, a uniform heat insulation effect can be obtained in the circumferential direction of the shaft portion 3b, and further suppression of devitrification of the molten glass Gm can be achieved.

[0070] Since the radial separation distance L3 between the heat insulation layer 7 and the flow path 3bx is shorter than the radial separation distance L4 between the heat insulation layer 7 and the outer peripheral surface 3ba of the shaft portion 3b, further miniaturization of the heat insulation layer 7 can be achieved, and the manufacturing cost can be further reduced.

[0071] The shaft portion 3b is configured by joining a first portion 3b1 and a second portion, and the heat insulation layer is provided on the first portion 3b1. Therefore, maintenance of the shaft portion 3b can be easily performed, and the heat insulation layer 7 is formed at an appropriate site in the axial direction of the roller portion 3a, that is, at an appropriate site for suppressing devitrification of the molten glass Gm.

[0072] Since one axial end portion of the heat insulation layer 7 is located at the joint portion 3bc between the first portion 3b1 and the second portion 3b2, maintenance of the heat insulation layer 7 can be easily performed. Further, since the fixing portion 3be is provided only at the end portion on the outer peripheral side of the joint portion 3bc, by allowing air to escape from the heat insulation layer 7 to the flow path 3bx, rupture or explosion of the shaft portion in a high-temperature atmosphere can be prevented.

[0073] Since the heat insulating portion 7 extends along the width direction in the lower region E of the edge guide 5 and the lower region F of the width direction end portion Gma of the molten glass Gm flowing down the molded body 2, devitrification of the molten glass Gm can be suppressed more efficiently. More specifically, since the edge guide 5 is made of metal, it is cooled significantly more than the molded body 2. Then, due to the cooling of the edge guide 5, devitrification is likely to occur particularly in the peripheral portion of the portion where the molten glass Gm contacts the edge guide 5 at the lower end portion of the molded body 2, that is, the region indicated by reference sign H in FIG. 5. This region H is included in the width direction end portion Gma of the molten glass Gm. Since the heat insulating layer 7 extends along the width direction in the lower region E of the edge guide 5, cooling of the edge guide 5 is suppressed, and devitrification in the region H of the molten glass Gm is efficiently suppressed. Further, since the heat insulating layer 7 also extends along the width direction in the lower region F of the width direction end portion Gma of the molten glass Gm, cooling of the region H of the molten glass Gm is directly suppressed, and devitrification in the region H is more reliably suppressed.

[0074] Since the position adjusting mechanism 8 for adjusting the vertical position of the edge roller 3 is provided, the vertical position of the edge roller 3 can be adjusted by the position adjusting mechanism 8 without causing layout problems. Moreover, when devitrification occurs in the molten glass Gm flowing down the molded body 2, generation of such devitrification can be suppressed by moving the edge roller 3 downward by the position adjusting mechanism 8.

[0075] Next, a method for manufacturing a glass article according to an embodiment of the present invention will be described. This manufacturing method includes a melting step, a transfer step, and a forming step.

[0076] The melting step is a step of generating molten glass Gm using a melting furnace. The transfer step is a step of transferring the molten glass Gm generated in the melting furnace to the above-described glass molding apparatus 1 using a feeder. The forming step is a step of forming a glass ribbon Gr from the molten glass Gm transferred by the feeder using the above-described glass molding apparatus 1. Then, a glass plate or a glass roll as a glass article can be obtained from this glass ribbon Gr.

[0077] As described above, the embodiments of the present invention have been explained. However, the embodiments of the present invention are not limited to this, and various modifications can be made without departing from the gist of the present invention.

[0078] For example, in the above embodiment, the heat insulation layer 7 is provided inside the shaft portion 3b of the edge roller 3, but the heat insulation layer 7 may be provided on the outer peripheral surface 3ba of the shaft portion 3b. As an example, a metal material having higher heat insulation properties than the material of the shaft portion 3b is used to perform metal spraying on the outer peripheral surface 3ba of the shaft portion 3b. In this way, a heat insulation effect can be obtained over a wide area of the shaft portion 3b.

[0079] In the above embodiment, the shaft portion 3b of the edge roller 3 is divided into two parts, the first part 3b1 and the second part 3b2, but it may not be divided, or it may be divided into three or more parts.

[0080] In the above embodiment, the space portion 3bb constituting the heat insulation layer 7 is filled with air, but other gases, for example, inert gases such as argon and krypton, may be filled in the space portion 3bb, or the space portion 3bb may be evacuated. Also, it is not necessary to intentionally fill the space portion 3bb with a gas, and the heat insulation layer 7 may be constituted by making the space portion 3bb in a state where a gas exists, that is, the heat insulation layer 7 may be constituted by storing a gas in the space portion 3bb.

[0081] In the above embodiment, the heat insulation layer 7 is constituted by filling the space portion 3bb with a gas, but the space portion 3bb may be filled with a heat insulating material such as fibers formed of a material having higher heat insulation properties than the material of the shaft portion 3b to constitute the heat insulation layer 7.

[0082] In the above embodiment, one type of heat insulation portion 7 is provided in the shaft portion 3b, but two or more types of heat insulation portions 7 may be provided. As an example, the above-described air layer 7 or the like is formed inside the shaft portion 3b, and the above-described metal spraying or the like is performed on the outer peripheral surface 3ba of the shaft portion 3b.

[0083] In the above embodiment, the space portion 3bb constituting the heat insulating layer 7 is not sealed, but when the strength of the shaft portion 3b is high, the space portion 3bb may be sealed.

[0084] In the above embodiment, the heat insulating portion is the heat insulating layer 7, but the heat insulating portion 7 may not be formed in layers. Further, the heat insulating portion 7 may be configured using a metal or ceramic having higher heat insulating properties than the material of the shaft portion 3b.

[0085] In the above embodiments, the present invention is applied to the glass forming apparatus 1 that forms the glass ribbon Gr using the overflow down-draw method. However, if it is provided with the edge roller 3 that sandwiches the widthwise end portion Gra of the glass ribbon Gr descending from the molded body 2, the present invention can be similarly applied to a glass forming apparatus that forms a glass ribbon using another down-draw method such as the slit down-draw method.

[0086] In the above embodiment, the present invention is applied when the edge guide 5 is attached to the molded body 2, but the present invention can be similarly applied even when the edge guide 5 is not attached to the molded body 2.

Example

[0087] The inventors of the present invention used, as an example, an edge roller having the structure shown in FIGS. 3 and 4 described above and in which the heat insulating layer 7 is configured by filling the space portion 3bb with air, and used, as a comparative example, an edge roller having the same structure and no heat insulating layer formed, and conducted the following experiment. First, the edge roller according to the example and the edge roller according to the comparative example were each placed in a calcining furnace, and a refrigerant was supplied and discharged through the supply path and the discharge path in the internal flow path of these edge rollers. The temperature in the calcining furnace in this case was set to 1200°C. Further, air was used as the refrigerant, and its temperature was set to 20°C. Under this state, it was measured how much the ambient temperature decreased above the shaft portion of the edge roller. The temperature measurement in this case was performed at a position 25 mm above the shaft portion. The measurement results are shown in Table 1 below.

Table 1

[0088] According to Table 1 above, in the examples, the temperature drop is small, while in the comparative examples, the temperature drop is large, and the difference is 8°C. Therefore, a sufficient heat insulation effect was obtained in the examples, while a sufficient heat insulation effect was not obtained in the comparative examples. Thus, it is understood that if the edge roller according to the examples is used in the glass forming apparatus 1, devitrification of the molten glass Gm can be appropriately suppressed.

Explanation of Reference Numerals

[0089] 1 Glass forming apparatus 2 Formed body 3 Edge roller 3a Roller part 3ax Cooling space 3b Shaft part 3b1 First part 3b2 Second part 3ba Outer peripheral surface of the shaft part 3bb Space part 3bc Joint part 3bx Flow path 3by Supply path 3bz Discharge path 4 Annealing roller 5 Edge guide 7 Heat insulation part (heat insulation layer) 8 Position adjustment mechanism E Region below the edge guide F Region below the widthwise end of the molten glass Gm Molten glass Gma Widthwise end of the molten glass Gr Glass ribbon Gra Widthwise end of the glass ribbon X Central axis line of the shaft part

Claims

1. A glass forming apparatus for forming a glass ribbon from molten glass by a down-draw method, comprising: A forming body and an edge roller that holds a width direction end portion of a glass ribbon descending from the forming body, The edge roller includes a roller portion that contacts the glass ribbon, a shaft portion to which the roller portion is attached, and a flow path that is provided inside the shaft portion and supplies and discharges a refrigerant to a cooling space inside the roller portion, The glass forming device according to claim 1, wherein the shaft portion is provided with a heat insulating portion.

2. 2. The glass forming apparatus according to claim 1, wherein the heat insulating portion is a heat insulating layer provided between an outer circumferential surface of the shaft portion and the flow passage.

3. 3. The glass forming apparatus according to claim 2, wherein the heat insulating layer is configured by storing a gas in a space formed between an outer circumferential surface of the shaft portion and the flow passage.

4. 4. The glass forming apparatus according to claim 3, wherein the gas is air.

5. 4. The glass forming apparatus according to claim 3, wherein the heat insulating layer has an elongated shape that is long along the axial direction in a cross section including a central axis of the shaft portion.

6. 6. The glass forming apparatus according to claim 5, wherein the heat insulating layer is formed along a circle having a center on the central axis of the shaft portion in a cross section perpendicular to the central axis of the shaft portion.

7. 7. The glass forming apparatus according to claim 6, wherein a radial distance between the heat insulating layer and the flow passage is shorter than a radial distance between the heat insulating layer and an outer circumferential surface of the shaft portion.

8. The glass forming device of any one of claims 2 to 7, characterized in that the shaft portion is constructed by joining a first portion located on the roller portion side in the axial direction and a second portion located on the opposite side of the roller portion side in the axial direction, and the insulating layer is provided on the first portion.

9. 8. The glass forming apparatus according to claim 2, wherein one axial end of the heat insulating layer is located at a joint between the first portion and the second portion.

10. 8. The glass forming apparatus according to claim 1, wherein the heat insulating portion extends along a width direction in a region below an end portion in a width direction of the molten glass flowing down the forming body.

11. The glass forming apparatus according to any one of claims 1 to 7, characterized in that the forming body is used to form a glass ribbon by an overflow downdraw method, an edge guide is attached to a widthwise end of the forming body, and the insulating section extends along the width direction in a region below the edge guide.

12. 8. The glass forming device according to claim 1, further comprising a position adjustment mechanism for adjusting the vertical position of the edge rollers.

13. 8. The glass forming apparatus according to claim 1, wherein the distance between the forming body and the shaft portion is 30 to 200 mm.

14. 2. The glass forming device according to claim 1, wherein the heat insulating portion is provided on an outer circumferential surface of the shaft portion.

15. The glass forming device according to any one of claims 1 to 7, characterized in that the flow path includes a supply path for supplying the refrigerant to the cooling space of the roller portion, and a discharge path for discharging the supplied refrigerant.

16. A method for producing a glass article, comprising a forming step of forming a glass ribbon from molten glass using the glass forming apparatus according to any one of claims 1 to 7.

17. An edge roller used to clamp a width direction end portion of a glass ribbon when forming a glass ribbon from molten glass by a down-draw method, A cooling device comprising: a roller portion that contacts the glass ribbon; a shaft portion to which the roller portion is attached; and a flow path that is provided inside the shaft portion and that supplies and discharges a refrigerant to a cooling space inside the roller portion, The edge roller, wherein the shaft portion is provided with a heat insulating portion.

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