Glass forming apparatus, method for manufacturing glass article, and edge roller

Abstract

The invention provides a glass forming device, a method for manufacturing a glass article, and an edge roller. The glass forming device can inhibit devitrification of molten glass and can obtain a glass ribbon with enough width direction length on the basis of avoiding layout problems and large-scale problems of the device. A glass molding device (1) for molding a glass ribbon (Gr) from molten glass (Gm) by a down-draw method, the glass molding device (1) being provided with a molding body (2) and an edge roller (3) for sandwiching a widthwise end portion (Gra) of the glass ribbon (Gr) descending from the molding body (2). The edge roller (3) is provided with: a roller part (3a) that is in contact with the glass ribbon (Gr); a shaft section (3b) to which the roller section (3a) is attached; and a flow path (3bx) that is provided inside the shaft section (3b) and that supplies and discharges a refrigerant to and from a cooling space (3ax) inside the roller section (3a). The shaft part (3b) is provided with a heat insulation part (7).

Description

Technical Field

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

[0002] As is well known, in the process of manufacturing a glass plate or a glass roll, measures are taken to form a glass ribbon 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 the overflow down-draw method.

[0003] Specifically, the glass forming apparatus disclosed in this document causes the molten glass overflowing from a groove formed at the top of a wedge-shaped forming body to flow down along both side surfaces of the forming body, and then fuses at the lower end of the forming body to form a glass ribbon. In this case, the widthwise end portions of the glass ribbon descending from the forming body are clamped by edge rollers that circulate a refrigerant inside.

[0004] In addition to this structure, the glass forming apparatus disclosed in this document also has a heat shield disposed above the edge roller and below the forming body in order to reduce the heat loss from an edge guide (an edge guide in this document) attached to the widthwise end of the forming body to the edge roller.

[0005] If the heat shield is arranged in this way, it is difficult to cause a problem that the edge guide of the forming body is improperly cooled by the edge roller, and therefore it is possible to expect suppression of devitrification of the molten glass that may occur around the edge guide at the lower end of the forming body.

[0006] Prior Art Documents

[0007] Patent Documents

[0008] Patent Document 1: Japanese Patent Application Laid-Open No. 2011-178657 Summary of the Invention

[0009] Problems to be Solved by the Invention

[0010] However, in the glass forming apparatus disclosed in this document, since a space for arranging the heat shield is required, the vertical separation distance between the forming body and the edge roller becomes long. In this case, the amount of shrinkage in the width direction of the glass ribbon immediately after descending from the forming body increases as it is transferred downward.

[0011] Therefore, when the above separation distance is long, the edge roller must clamp the glass ribbon at a position where the widthwise length of the glass ribbon is unduly shortened, and it becomes difficult to obtain a glass ribbon with a sufficient widthwise length after forming.

[0012] Moreover, in the glass forming apparatus disclosed in this document, due to the rotation of the edge roller, it is necessary to separate the heat shield from the edge roller, thus causing problems in layout and enlargement of the apparatus.

[0013] From the above viewpoints, the object of the present invention is to obtain a glass ribbon with a sufficient length in the width direction while suppressing devitrification of the molten glass, while avoiding problems in layout and enlargement of the apparatus.

[0014] Means for Solving the Problems

[0015] (1) The first aspect of the present invention made to solve the above problems is a glass forming apparatus for forming a glass ribbon from molten glass by the down-draw method. The glass forming apparatus is characterized in that the glass forming apparatus includes a forming body and an edge roller that clamps the widthwise ends of the glass ribbon descending from the forming body. The edge roller includes: a roller portion that contacts the glass ribbon; a shaft portion on which the roller portion is mounted; 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 has a heat insulating portion. Here, the edge roller means the uppermost stage roller among the upper and lower multi-stage rollers that clamp the widthwise ends of the glass ribbon descending from the forming body.

[0016] According to this structure, since the shaft portion of the edge roller has a heat insulating portion, the following effects are obtained. First, it suppresses devitrification that may occur at the widthwise ends of the molten glass at the lower end portion of the forming body. Specifically, although the shaft portion of the edge roller does not contact the glass ribbon, its temperature decreases significantly due to being 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, and devitrification is likely to occur. According to the present structure, since the shaft portion has a heat insulating portion, such devitrification in 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 edge roller can clamp the glass ribbon at a position where the shrinkage amount in the width direction of the glass ribbon descending from the forming body is small. Therefore, a glass ribbon with a sufficient length in the width direction can be obtained. Third, there is no need to additionally arrange other heat insulating members between the forming body and the edge roller, so problems in layout and enlargement of the apparatus do not occur.

[0017] (2) In the structure 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.

[0018] In this way, compared with the case where the heat insulating layer is provided at a position outside the outer peripheral surface of the shaft portion, miniaturization of the shaft portion can be achieved, and deterioration, consumption, etc. of the heat insulating layer can be reduced.

[0019] (3) In the structure of (2) above, it is also possible that the heat insulation layer is formed by storing gas in the space between the outer peripheral surface of the shaft portion and the flow path.

[0020] In this way, the structure of the heat insulation layer can be simplified, and the heat insulation effect can be obtained efficiently.

[0021] (4) In the structure of (3) above, it is also possible that the gas is air.

[0022] In this way, the heat insulation effect can be obtained efficiently while reducing the manufacturing cost of the heat insulation layer.

[0023] (5) In any one of the structures of (2) to (4) above, it is also possible that the heat insulation layer is in a long and slender shape along the axial direction in a cross section including the central axis of the shaft portion.

[0024] In this way, the heat insulation effect is obtained in a wide area in the axial direction of the shaft portion, so that devitrification of the molten glass can be suppressed in a wide area in the width direction.

[0025] (6) In any one of the structures of (2) to (5) above, it is also possible that the heat insulation layer is formed in a circular shape centered on the central axis in a cross section orthogonal to the central axis of the shaft portion.

[0026] In this way, a uniform heat insulation effect is obtained in the circumferential direction of the shaft portion, so that devitrification of the molten glass can be further suppressed.

[0027] (7) In any one of the structures of (2) to (6) above, it is also possible that the radial separation distance between the heat insulation layer and the flow path is shorter than the radial separation distance between the heat insulation layer and the outer peripheral surface of the shaft portion.

[0028] In this way, further miniaturization of the heat insulation layer is achieved, and the manufacturing cost can be further reduced.

[0029] (8) In any one of the structures of (2) to (7) above, it is also possible that the shaft portion is formed by joining a first part on the roller portion side in the axial direction and a second part on the side opposite to the roller portion side in the axial direction, and the heat insulation layer is provided on the first part.

[0030] In this way, maintenance of the shaft portion can be easily performed, and the heat insulation layer is formed at an appropriate position in the axial direction of the shaft portion, that is, a position close to the portion where devitrification of the molten glass that is likely to cause the formed body to flow down easily occurs. Therefore, devitrification of the molten glass can be effectively suppressed.

[0031] (9) In any one of the structures of (2) to (7) above, it is also possible that one axial end portion of the heat insulation layer is located at the joint portion where the first part and the second part are joined.

[0032] In this way, the maintenance of the heat insulation layer can be easily carried out, and a gap leading from the heat insulation layer to the flow path side or the outer peripheral side of the shaft portion is provided at the joint portion, so that air or the like existing in the heat insulation layer can escape, and the rupture, explosion, etc. of the shaft portion in a high-temperature atmosphere can be prevented. In addition, the manufacturing cost of the heat insulation layer can be greatly reduced.

[0033] (10) In any one of the above structures (1) to (9), it is also possible that the heat insulation portion extends in the width direction in a region below the width direction end of the molten glass of the flowing-down forming body.

[0034] In this way, a sufficient and reliable heat insulation effect can be obtained for the portion where devitrification of the molten glass of the flowing-down forming body is likely to occur, that is, the peripheral portion of the width direction end of the molten glass at the lower end of the flowing-down forming body.

[0035] (11) In any one of the above structures (1) to (10), it is also possible that the forming body is used for forming a glass ribbon by the overflow down-draw method, an edge guide is installed at the width direction end of the forming body, and the heat insulation portion extends in the width direction in a region below the edge guide.

[0036] In this way, the devitrification of the molten glass caused by the cooling of the edge guide by the shaft portion is suppressed. Specifically, if the edge guide is cooled, devitrification is likely to occur in the periphery of the portion where the molten glass contacts the edge guide at the lower end of the forming body. According to the structure here, since the cooling of the edge guide is suppressed by the heat insulation portion provided in the shaft portion, the generation of such devitrification is suppressed.

[0037] (12) In any one of the above structures (1) to (11), it is also possible that the glass forming device is provided with a position adjusting mechanism for adjusting the vertical position of the edge roller.

[0038] In this way, the vertical position of the edge roller can be adjusted by the position adjusting mechanism without causing layout problems. And when devitrification occurs in the molten glass of the flowing-down forming body, by moving the edge roller downward using the position adjusting mechanism, the generation of such devitrification can be suppressed.

[0039] (13) In any one of the above structures (1) to (12), it is also possible that the separation distance between the forming body and the shaft portion is 30 to 200 mm.

[0040] In this way, 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 forming body is small, so that a glass ribbon with a sufficient width direction length can be obtained.

[0041] (14) In any one of the above structures (1) to (13), it is also possible that the heat insulation portion is provided on the outer peripheral surface of the shaft portion.

[0042] In this way, it is possible to prevent the enlargement of the shaft portion while obtaining a heat insulation effect over a large area 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 cite metal spraying the outer peripheral surface of the shaft portion with a metal material having a higher heat insulation property than the material of the shaft portion.

[0043] (15) In any of the structures (1) to (14) above, the flow path may include a supply path for supplying the refrigerant to the cooling space of the roll portion and a discharge path for discharging the supplied refrigerant.

[0044] In this way, it is possible to smoothly supply and discharge the refrigerant inside the shaft portion and inside the roll portion.

[0045] (16) A second aspect of the present invention made to solve the above problems is a method for manufacturing a glass article, characterized in that the method for manufacturing the glass article includes a forming step of forming a glass ribbon from molten glass using any one of the glass forming devices (1) to (15) above.

[0046] According to this method, substantially the same operational effects as those of any one of the glass forming devices (1) to (15) above are obtained.

[0047] (17) A third aspect of the present invention made to solve the above problems is an edge roll for clamping the end portions in the width direction of a glass ribbon when forming the glass ribbon from molten glass by the down-draw method. The edge roll is characterized in that the edge roll includes: a roll portion that contacts the glass ribbon; a shaft portion to which the roll 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 roll portion, and the shaft portion has a heat insulation portion.

[0048] If the edge roll having such a heat insulation portion is used in a glass forming device for forming a glass ribbon from molten glass by the down-draw method, substantially the same operational effects as those of the structure (1) above are obtained.

[0049] Advantages of the Invention

[0050] According to the present invention, it is possible to obtain a glass ribbon having a sufficient length in the width direction while avoiding problems with the layout and enlargement of the device, and while suppressing the devitrification of the molten glass. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 is a front view showing the main part structure of the glass forming device according to an embodiment of the present invention.

[0052] Figure 2 is a perspective view showing the main part structure of the glass forming device according to an embodiment of the present invention.

[0053] Figure 3 It is a longitudinal sectional front view of an edge roll which is a component of a glass forming apparatus as an embodiment of the present invention.

[0054] Figure 4 It is a longitudinal sectional front view of an edge roll which is a component of a glass forming apparatus as an embodiment of the present invention.

[0055] Figure 5 It is a front view showing an enlarged view of the main part structure of a glass forming apparatus as an embodiment of the present invention.

[0056] Figure 6 It is a schematic front view showing an up - and - down adjustment mechanism which is a component of a glass forming apparatus as an embodiment of the present invention.

[0057] Explanation of reference numerals

[0058] 1 Glass forming apparatus

[0059] 2 Formed body

[0060] 3 Edge roll

[0061] 3a Roll part

[0062] 3ax Cooling space

[0063] 3b Shaft part

[0064] 3b1 First part

[0065] 3b2 Second part

[0066] 3ba Outer peripheral surface of the shaft part

[0067] 3bb Space part

[0068] 3bc Joint part

[0069] 3bx Flow path

[0070] 3by Supply path

[0071] 3bz Discharge path

[0072] 4 Annealing roll

[0073] 5 Edge guide

[0074] 7 Heat insulation part (heat insulation layer)

[0075] 8 Position adjustment mechanism

[0076] E Lower region of the edge guide

[0077] F Lower region of the width - direction end of the molten glass

[0078] Gm Molten glass

[0079] Gma Widthwise end portions of the molten glass

[0080] Gr Glass ribbon

[0081] Gra Widthwise end portions of the glass ribbon

[0082] Central axis of the X-axis portion. Detailed implementation manners

[0083] 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. It should be noted that the glass forming apparatus according to the following embodiment is used in the case of forming a glass ribbon by the overflow down-draw method.

[0084] Figure 1 is a front view showing the main part structure of the glass forming apparatus 1 according to an embodiment of the present invention, Figure 2 is a perspective view showing the main part of the apparatus 1. It should be noted that, based on Figure 1 and Figure 2 in the description, the A-A direction is denoted as the width direction (the same applies to Figure 5 described later), and the B-B direction (refer to Figure 2 ) is denoted as the thickness direction. In addition, Figure 1 and Figure 2 the main parts of the glass forming apparatus 1 shown are of the same structure on both sides in the width direction and of the same structure on both sides in the thickness direction.

[0085] As Figure 1 and Figure 2 shown, the glass forming apparatus 1 includes a forming body 2, an edge roller 3, and an annealing roller 4 as main components.

[0086] Both side surfaces 2a of the forming body 2 that exist on both sides in the thickness direction are respectively composed of a vertical surface portion 2aa and an inclined surface portion 2ab connected to the lower end of the vertical surface portion 2aa. An overflow groove 2b extending in the width direction is formed at the top of the forming body 2. Edge guides 5 are respectively installed at both ends in the width direction of the forming body 2. The edge guides 5 restrict 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 forming body 2 flows down along both side surfaces 2a of the forming body 2. Therefore, the widthwise end portions Gma of the molten glass Gm flowing down along both side surfaces 2a of the forming body 2 come into contact with the edge guides 5. The edge guides 5 are formed of a plate made of a metal such as platinum or a platinum alloy. The forming body 2 is formed of refractory bricks.

[0087] The edge rollers 3 respectively hold both end portions Gra in the width direction of the glass ribbon Gr below the forming body 2. Specifically, both end portions Gra in the width direction of the glass ribbon Gr descending from the forming body 2 are respectively held 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 feeding the glass ribbon Gr downward. It should be noted that these edge rollers 3 may also be provided in multiple levels (for example, two levels) in the vertical direction. In the case of two levels in the vertical direction, it is preferable that the upper-level edge rollers 3 are driving rollers and the lower-level edge rollers 3 are free rollers.

[0088] The annealing rollers 4 respectively hold both end portions Gra in the width direction of the glass ribbon Gr below the edge rollers 3 and are provided in multiple levels in the vertical direction. Thus, both end portions Gra in the width direction of the glass ribbon Gr are respectively held by each pair of annealing rollers 4 in multiple levels in the vertical direction. Most or all of these annealing rollers 4 are driving rollers for feeding the glass ribbon Gr downward.

[0089] Hereinafter, the structure and the function and effect of the edge roller 3 will be described in detail. It should be noted that in the case where the edge roller 3 is provided in multiple levels in the vertical direction, the structure and the function and effect of the uppermost-level edge roller 3 will be described below.

[0090] Figure 3 is a longitudinal sectional front view showing the structure of the edge roller 3, Figure 4 is according to Figure 3 the sectional view taken along the C-C line of. As Figure 3 shown, the edge roller 3 includes: a roller portion 3a that contacts the glass ribbon Gr; and a shaft portion 3b that mounts the roller portion 3a.

[0091] A cooling space 3ax for supplying and discharging a refrigerant is provided inside the roller portion 3a. Thus, the roller portion 3a cools both end portions Gra in the width direction of the glass ribbon Gr and functions to restrict the shrinkage of the glass ribbon Gr in the width direction. As the refrigerant, water or air is used.

[0092] In the present embodiment, the shaft portion 3b is divided into a first portion 3b1 on the roller portion 3a side in the axial direction and a second portion 3b2 on the side opposite to the roller portion 3a side in the axial direction, and is formed 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 the first portion 3b1 preferably has higher heat resistance than the second portion 3b2.

[0093] A flow path 3bx for supplying and discharging a refrigerant is provided inside the shaft portion 3b. The flow path 3bx includes: a supply path 3by that supplies the refrigerant to the cooling space 3ax of the roller portion 3a; and a discharge path 3bz that discharges 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.

[0094] As a feature of the edge roller 3, the shaft portion 3b is provided with a heat insulating portion 7. The heat insulating portion 7 is a heat insulating layer provided between the outer peripheral surface 3ba of the shaft portion 3b and the flow path 3bx. The heat insulating layer 7 is formed by filling a gas in a space portion 3bb formed between the outer peripheral surface 3ba of the shaft portion 3b and the flow path 3bx. As the gas, air is used. Air at room temperature is supplied to the supply path 3by, for example, as a refrigerant.

[0095] The heat insulating layer 7 is Figure 3 shown in the cross section, that is, in the cross section including the central axis X of the shaft portion 3b, it has an elongated shape along the axial direction. In addition, the heat insulating layer 7 is formed in a circular shape centered on its central axis X in the Figure 4 shown cross section, that is, in the cross section orthogonal to the central axis X of the shaft portion 3b. The axial length L1 of the heat insulating layer 7 is 20 to 300 mm, preferably 40 to 150 mm (see Figure 3 ). In addition, the radial length L2 of the heat insulating layer 7 is 0.1 to 20 mm, preferably 0.1 to 5 mm (see Figure 4 ).

[0096] Moreover, as Figure 3 shown, the radial separation distance L3 between the heat insulating layer 7 and the flow path 3bx is shorter than the radial separation distance L4 between the heat insulating layer 7 and the outer peripheral surface 3ba of the shaft portion 3b. In addition, the heat insulating layer 7 is provided in the first portion 3b1 of the shaft portion 3b. And, one axial end portion of the heat insulating layer 7 is located at the joint portion 3bc where the first portion 3b1 and the second portion 3b2 are joined. In other words, one axial end portion of the heat insulating layer 7 opens at the joint surface 3bd of the first portion 3b1. In this case, the first portion 3b1 and the second portion 3b2 are fixedly connected only at their outer peripheral side ends by welding or the like. Thus, in their joint portion 3bc, only the outer peripheral side ends are provided with a fixing portion 3be. 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 in the joint portion 3bc.

[0097] In addition, as Figure 5As shown, the heat insulating layer 7 extends along the width direction in the lower region E of the edge guide 5 mounted on the forming body 2. Specifically, the heat insulating layer 7 includes the lower region E of the edge guide 5 in the width direction and extends outwards from this lower region E towards both sides in the width direction. Moreover, 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 forming 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 extends outwards from this lower region F towards both sides in the width direction. In this case, the separation distance L5 between the forming body 2 and the shaft portion 3b of the edge roll 3 is preferably 30 to 200 mm, more preferably 30 to 50 mm.

[0098] Moreover, the edge roll 3 is held in a manner capable of vertical position adjustment. Specifically described, as Figure 6 shown, the edge roll 3 is configured to have its vertical position adjusted by a position adjustment mechanism 8. This position adjustment mechanism 8 is a structure in which a support portion 9 that supports the edge roll 3 is held on a moving base 10 and the moving base 10 is moved up and down by a driving device 11. The support portion 9 is composed of a bearing that holds the axial end portion of the shaft portion 3b of the edge roll 3 rotatably, a motor that imparts a rotational driving force to the shaft portion 3b, and the like. In the illustrated example, as the driving device 11, a plurality of fluid pressure cylinders 11a such as air cylinders are used, but it may also be other driving devices such as a ball screw mechanism, a device using a workbench capable of sliding up and down. In this case, the driving device 11 is provided on a support member 12 such as a member constituting the furnace wall surrounding the forming body 2, a member fixed to this furnace wall.

[0099] According to the glass forming apparatus 1 having the above structure, the following effects can be achieved.

[0100] Since the shaft portion 3b of the edge roll 3 is provided with the heat insulating portion 7, devitrification of the molten glass Gm can be efficiently suppressed. Specifically described, although the shaft portion 3b of the edge roll 3 does not contact the glass ribbon Gr, its temperature is greatly reduced due to being cooled by a refrigerant. Therefore, the width direction end Gma of the molten glass Gm flowing down the forming body 2 is cooled by the shaft portion 3b at the lower end portion of the forming body 2, and devitrification is likely to occur. In contrast, if the shaft portion 3b is provided with the heat insulating portion 7, such devitrification in the molten glass Gm can be suppressed.

[0101] Since the shaft portion 3b of the edge roller 3 is provided with the heat insulating portion 7, it is not necessary to additionally arrange other members for heat insulation between the edge roller 3 and the formed body 2, and the separation distance in the vertical direction between the edge roller 3 and the formed body 2 can be shortened. Therefore, the glass ribbon Gr descending from the formed body 2 can be clamped by the edge roller 3 at a position where the shrinkage amount in the width direction is small. Thus, a glass ribbon Gr with a sufficient length in the width direction can be obtained. In addition, since it is not necessary to additionally arrange other members for heat insulation between the edge roller 3 and the formed body 2, problems with the layout and the enlargement of the glass forming apparatus 1 will not occur.

[0102] Since the heat insulating portion 7 is a heat insulating layer provided between the outer peripheral surface 3ba of the shaft portion 3b and the flow path 3bx, miniaturization of the heat insulating layer 7 is achieved, and the manufacturing cost can be reduced. Specifically described, such a heat insulating layer 7 may also be provided on the outer peripheral side of the outer peripheral surface 3ba of the shaft portion 3b, but compared with that case, miniaturization of the heat insulating layer 7 is achieved, and the manufacturing cost can be reduced.

[0103] Since the heat insulating layer 7 is formed by filling air in 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 insulating layer 7 is provided at a position on the outer peripheral side of the outer peripheral surface 3ba of the shaft portion 3b, miniaturization of the shaft portion 3b can be achieved, and deterioration, loss, etc. of the heat insulating layer 7 can be reduced.

[0104] Since the heat insulating layer 7 is in a long and slender shape along the axial direction in a cross section including the central axis X of the shaft portion 3b, a heat insulating effect is 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 width direction.

[0105] Since the heat insulating layer 7 is formed in a manner along a circle centered on its central axis X in a cross section orthogonal to the central axis X of the shaft portion 3b, an even heat insulating effect is obtained in the circumferential direction of the shaft portion 3b, and devitrification of the molten glass Gm can be further suppressed.

[0106] Since the radial separation distance L3 between the heat insulating layer 7 and the flow path 3bx is shorter than the radial separation distance L4 between the heat insulating layer 7 and the outer peripheral surface 3ba of the shaft portion 3b, further miniaturization of the heat insulating layer 7 is achieved, and the manufacturing cost can also be further reduced.

[0107] Since the shaft portion 3b is formed by joining the first portion 3b1 and the second portion, and the heat insulating layer is provided on the first portion 3b1, maintenance of the shaft portion 3b can be easily performed, and the heat insulating layer 7 is formed at an appropriate position in the axial direction of the roller portion 3a, that is, at an appropriate position in terms of suppressing devitrification of the molten glass Gm.

[0108] One axial end of the heat insulation layer 7 is located at the joint 3bc where the first part 3b1 and the second part 3b2 are joined, so that the maintenance of the heat insulation layer 7 can be easily performed. In addition, since there is only a fixing part 3be at the end on the outer peripheral side of the joint 3bc, air escapes from the heat insulation layer 7 to the flow path 3bx, thereby preventing the rupture or explosion of the shaft part in the high-temperature atmosphere, etc.

[0109] Since the heat insulation part 7 extends in the width direction in the lower region E of the edge guide 5 and in the lower region F of the width direction end Gma of the molten glass Gm flowing down the forming body 2, the devitrification of the molten glass Gm can be more efficiently suppressed. Specifically described, the edge guide 5 is made of metal, so it is cooled much more than the forming body 2. And because the edge guide 5 is cooled, in the peripheral part of the part where the molten glass Gm contacts the edge guide 5 at the lower end of the forming body 2, that is, in the Figure 5 region indicated by the reference numeral H in particular, devitrification is likely to occur in the molten glass Gm. This region H is included in the width direction end Gma of the molten glass Gm. Since the heat insulation layer 7 extends in the width direction in the lower region E of the edge guide 5, the cooling of the edge guide 5 is suppressed, and the devitrification at the above-mentioned region H of the molten glass Gm is efficiently suppressed. In addition, since the heat insulation layer 7 also extends in the width direction in the lower region F of the width direction end Gma of the molten glass Gm, the cooling of the above-mentioned region H of the molten glass Gm is directly suppressed, and the devitrification at the above-mentioned region H is more reliably suppressed.

[0110] Since the position adjustment 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 adjustment mechanism 8 without causing layout problems. And when devitrification occurs in the molten glass Gm of the flowing-down forming body 2, by using the position adjustment mechanism 8 to move the edge roller 3 downward, the generation of such devitrification can be suppressed.

[0111] 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 process, a transfer process, and a forming process.

[0112] The melting process is a process of generating molten glass Gm using a melting furnace. The transfer process is a process of transferring the molten glass Gm generated by the melting furnace to the above-mentioned glass forming device 1 using a feeder. The forming process is a process of forming a glass ribbon Gr from the molten glass Gm transferred by the feeder using the above-mentioned glass forming device 1. Then, a glass plate or a glass roll as a glass article is obtained from this glass ribbon Gr.

[0113] The above has described the embodiments of the present invention, but the embodiments of the present invention are not limited thereto, and various changes can be made without departing from the gist of the present invention.

[0114] For example, in the above-described embodiment, a heat insulating layer 7 is provided inside the shaft portion 3b of the edge roller 3, but the heat insulating layer 7 may also be provided on the outer peripheral surface 3ba of the shaft portion 3b. As an example, it is possible to perform metal spraying on the outer peripheral surface 3ba of the shaft portion 3b using a metal material having a higher heat insulating property than the material of the shaft portion 3b. In this way, a heat insulating effect can be obtained over a wide area of the shaft portion 3b.

[0115] In the above-described embodiment, the shaft portion 3b of the edge roller 3 is divided into two parts, i.e., a first part 3b1 and a second part 3b2, but it may not be divided, or it may be divided into three or more parts.

[0116] In the above-described embodiment, air is filled in the space portion 3bb that constitutes the heat insulating layer 7, but other gases, such as inert gases like argon and krypton, may be filled in the space portion 3bb, or the space portion 3bb may be made into a vacuum. Additionally, the space portion 3bb may be intentionally left unfilled with gas, or it may be in a state where gas exists in the space portion 3bb to constitute the heat insulating layer 7, that is, gas may be stored in the space portion 3bb to constitute the heat insulating layer 7.

[0117] In the above-described embodiment, the heat insulating layer 7 is constituted by filling gas in the space portion 3bb, but the heat insulating layer 7 may also be constituted by inserting a heat insulating material such as fibers formed of a material having a higher heat insulating property than the material of the shaft portion 3b into the space portion 3bb.

[0118] In the above-described embodiment, one kind of heat insulating portion 7 is provided in the shaft portion 3b, but two or more kinds of heat insulating portions 7 may also be provided. As an example, it is possible to form the above-described air layer 7 inside the shaft portion 3b and perform the above-described metal spraying on the outer peripheral surface 3ba of the shaft portion 3b.

[0119] In the above-described embodiment, the space portion 3bb that constitutes the heat insulating layer 7 is not sealed, but the space portion 3bb may be sealed when the strength of the shaft portion 3b is high.

[0120] In the above-described embodiment, the heat insulating portion is the heat insulating layer 7, but the heat insulating portion 7 may not be formed in a layer shape. Additionally, a metal, ceramic, etc. having a higher heat insulating property than the material of the shaft portion 3b may be used to constitute the heat insulating portion 7.

[0121] In the above embodiment, the present invention is applied to the glass forming apparatus 1 that forms the glass ribbon Gr by the overflow down-draw method. However, as long as it has an edge roller 3 that clamps the widthwise end portion Gra of the glass ribbon Gr descending from the forming body 2, the present invention can also be similarly applied to, for example, a glass forming apparatus that forms a glass ribbon by another down-draw method such as the slot down-draw method.

[0122] In the above-described embodiment, the present invention is applied in the case where the edge guide 5 is installed on the formed body 2. However, the present invention can also be similarly applied in the case where the edge guide 5 is not installed on the formed body 2.

[0123] Example

[0124] The inventors of the present invention have described the Figure 3 and Figure 4 The edge roll having the structure shown and in which the heat insulating layer 7 is formed by filling air in the space portion 3bb was used as an example, and the edge roll having the same structure and without the heat insulating layer was used as a comparative example, and the following experiments were conducted. First, the edge roll of the example and the edge roll of the comparative example were respectively placed in a calcining furnace, and the refrigerant was supplied and discharged through the supply path and the discharge path in the flow path inside these edge rolls. The temperature in the calcining furnace in this case was set to 1200°C. In addition, air was used as the refrigerant, and its temperature was set to 20°C. In this state, the temperature reduction of the atmosphere temperature above the shaft portion of the edge roll was measured. The temperature measurement in this case was performed at a position 25 mm separated upward from the shaft portion. The measurement results are shown in Table 1 below.

[0125] Table 1

[0126]

[0127] According to Table 1 above, the temperature reduction was small in the example and large in the comparative example, and the difference was 8°C. Therefore, a sufficient heat insulating effect was obtained in the example, whereas a sufficient heat insulating effect was not obtained in the comparative example. Thus, it is interpreted that if the edge roll of the example is used in the glass forming apparatus 1, the devitrification of the molten glass Gm can be appropriately suppressed.

Claims

1. A glass forming device for forming a glass ribbon from molten glass by a down-draw method, The glass forming device is characterized in that: The glass forming device includes a forming body and edge rollers for clamping widthwise ends of a glass ribbon descending from the forming body. The edge roller comprises: a roller portion that contacts the glass ribbon; a shaft portion that mounts the roller portion; and a flow path that is provided inside the shaft portion and supplies and discharges a cooling medium with respect to a cooling space inside the roller portion. The shaft portion includes a heat insulating portion.

2. The glass forming device according to claim 1, characterized in that: The heat insulating portion is a heat insulating layer provided between the outer peripheral surface of the shaft portion and the flow path.

3. The glass forming device according to claim 2, characterized in that: The heat insulating layer is formed by storing gas in a space portion formed between the outer peripheral surface of the shaft portion and the flow path.

4. The glass forming device according to claim 3, characterized in that: The gas is air.

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

6. The glass forming device according to claim 5, characterized in that: The heat insulating layer is formed along a circle centered on the central axis in a cross section perpendicular to the central axis of the shaft portion.

7. The glass forming device according to claim 6, characterized in that: A radial separation distance between the heat insulating layer and the flow path is shorter than a radial separation distance between the heat insulating layer and an outer peripheral surface of the shaft portion.

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

9. The glass forming device according to any one of claims 2 to 7, characterized in that: One axial end portion of the heat insulation layer is located at a joint portion where the first portion and the second portion are joined.

10. The glass forming device according to any one of claims 1 to 7, characterized in that: The heat insulating portion extends in the width direction in a region below the width direction end portions of the molten glass flowing down the forming body.

11. The glass forming device 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 down-draw method. An edge guide is installed at an end portion in the width direction of the forming body. The heat insulating portion extends in the width direction at a region below the edge guide.

12. The glass forming device according to any one of claims 1 to 7, characterized in that: The glass forming apparatus includes a position adjustment mechanism for adjusting the vertical position of the edge roller.

13. The glass forming device according to any one of claims 1 to 7, characterized in that: The separation distance between the molded body and the shaft portion is 30 to 200 mm.

14. The glass forming device according to claim 1, characterized in that: The heat insulating portion is provided on the outer peripheral 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 cooling medium to the cooling space of the roller portion and a discharge path for discharging the supplied cooling medium.

16. A method for manufacturing a glass article, wherein: The method for producing the glass article comprises 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 for clamping the widthwise end of a glass ribbon when forming a glass ribbon from molten glass by a down-draw method, The edge roller is characterized in that The edge roller comprises: a roller portion that contacts the glass ribbon; a shaft portion that mounts the roller portion; and a flow path that is provided inside the shaft portion and supplies and discharges a cooling medium with respect to a cooling space inside the roller portion. The shaft portion includes a heat insulating portion.

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