Support roll, glass sheet forming device, and glass sheet forming method

Abstract

To provide a support roll that can suppress cooling of an annular abutment part and reduce accumulation of deposit on a surface of the annular abutment part.SOLUTION: A support roll for supporting a strip-like glass ribbon includes: a fitting member including a cooling flow channel therein; and an annular abutment part including a recess to which an end of the fitting member is fitted.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a support roll, a glass sheet forming apparatus, and a glass sheet forming method. [Background technology]

[0002] When molten glass is formed into a band-shaped glass ribbon, for example, the float process is widely used. In the float process, molten glass is supplied onto the upper surface of molten tin stored in a float bath, and the molten glass that spreads on the upper surface of the molten tin is guided downstream to form a band-shaped glass ribbon. In this process, a glass ribbon that is thinner than its equilibrium thickness tends to shrink in the width direction. Therefore, in order to adjust the glass ribbon to a desired thickness and width, support rolls are used that rotate while applying tension to the glass ribbon in the width direction to transport the glass ribbon.

[0003] As a support roll, for example, a top roll is disclosed that includes an attachment member provided with a cooling structure and an annular abutment portion provided so as to surround the circumference of the attachment member (see, for example, Patent Document 1).

[0004] The top roll in Patent Document 1 presses from above the widthwise ends of a glass ribbon formed by molten glass supplied onto the surface of molten tin stored in a float bath, thereby rotating while supporting the glass ribbon and transporting it downstream of the float bath. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 6070432 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the top roll of Patent Document 1, the annular contact portion is cooled by a cooling structure provided inside the mounting member, and as a result, the molten tin present near the annular contact portion is locally cooled, which may cause tin products that volatilize from the surface of the molten tin to aggregate and accumulate on the surface of the annular contact portion. There is a problem in that the deposits accumulated on the surface of the molten tin fall onto the surface of the glass ribbon flowing in the float bath due to their own weight or the rotation of the top roll.

[0007] The glass ribbon at the position where the deposits have fallen becomes unusable, which reduces the yield of glass sheets ultimately produced relative to the amount of molten glass used, thereby reducing the efficiency of glass sheet production.

[0008] An object of one aspect of the present invention is to provide a support roll that can suppress cooling of the annular contact portion and reduce deposition of deposits on the surface of the annular contact portion. [Means for solving the problem]

[0009] One aspect of the support roll according to the present invention is a support roll that supports a band-shaped glass ribbon, and includes an attachment member having a cooling flow path therein, and an annular abutment portion having a recess into which an end of the attachment member is fitted. [Effects of the Invention]

[0010] One aspect of the support roll according to the present invention can suppress cooling of the annular contact portion, thereby reducing deposition of deposits on the surface of the annular contact portion. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a schematic plan view showing the internal structure of a glass sheet forming device to which a support roll according to an embodiment of the present invention is applied. [Figure 2] FIG. 2 is a partial cross-sectional view of the glass sheet forming device showing the side of the support roll. [Figure 3] FIG. 2 is a cross-sectional view taken along the axial direction of the support roll. [Figure 4]FIG. 2 is a front view of the support roll as viewed along its axial direction. [Figure 5] FIG. 4 is a cross-sectional view showing a state in which the support roll is separated. [Figure 6] FIG. 10 is a front view showing an example of another configuration of the uneven portion when the annular contact portion is viewed along the axial direction of the support roll. [Figure 7] FIG. 10 is a cross-sectional view showing an example of another configuration of the uneven portion along the axial direction of the support roll. [Figure 8] FIG. 10 is a cross-sectional view showing an example of another configuration of the annular contact portion along the axial direction of the support roll. [Figure 9] FIG. 10 is a cross-sectional view showing an example of another configuration of the annular contact portion along the axial direction of the support roll. [Figure 10] FIG. 10 is a front view showing an example of another configuration of the annular contact portion when viewed along the axial direction of the support roll. [Figure 11] FIG. 10 is a cross-sectional view showing an example of another configuration of the support roll. [Figure 12] FIG. 10 is a cross-sectional view showing an example of another configuration of the support roll. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present invention will be described in detail. To facilitate understanding of the description, the same components in each drawing are denoted by the same reference numerals, and duplicate descriptions will be omitted. In this specification, unless otherwise specified, the symbol "to" indicating a range of values ​​means that the values ​​before and after it are included as the lower and upper limits.

[0013] A support roll according to an embodiment of the present invention will be described. The support roll according to this embodiment is used when producing a band-shaped glass ribbon from molten glass in a glass sheet forming device. The glass sheet forming device to which the support roll according to this embodiment is applied can be applied to general glass ribbon forming methods such as the float method and the fusion method, but in this embodiment, a case where a glass sheet is formed using the float method will be described.

[0014] <Glass sheet forming equipment> Fig. 1 is a schematic plan view showing the internal structure of a glass sheet forming apparatus to which a support roll according to this embodiment is applied, and Fig. 2 is a partial cross-sectional view of the glass sheet forming apparatus showing the side of the support roll. As shown in Fig. 1, the glass sheet forming apparatus 1 has a float bath 10 and support rolls 20, and forms a glass ribbon GR from molten glass MG supplied from a glass melting furnace 2 and forms the glass ribbon GR into a glass sheet G.

[0015] 1 uses a three-dimensional Cartesian coordinate system with three axes (X-axis, Y-axis, and Z-axis), with the width direction of the float bath 10 defined as the X-axis direction, the length direction defined as the Y-axis direction, and the height direction defined as the Z-axis direction. In the following description, one side of the height direction of the float bath 10 may be referred to as the top or upper side, and the other side may be referred to as the bottom or lower side.

[0016] The length direction of the float bath 10 is the left-right direction in Fig. 1, and in this specification, is the conveying direction (flow direction) of the glass ribbon GR. The width direction of the float bath 10 is the up-down direction in Fig. 1, and is the width direction perpendicular to the conveying direction of the glass ribbon GR.

[0017] In this specification, the conveying direction of the glass ribbon GR is the direction in which the glass ribbon GR is conveyed from the upstream side to the downstream side in a plan view. In addition, in this specification, the upstream side and the downstream side are relative to the conveying direction (Y-axis direction) of the glass ribbon GR in the float bath 10. That is, in this specification, the +Y-axis direction is the downstream side, and the −Y-axis direction is the upstream side.

[0018] In this specification, the inside in the width direction (X-axis direction) refers to the side in the width direction where the center of the width direction of the float bath 10 is located. The outside in the width direction refers to the side opposite to the side in the width direction where the center of the width direction of the float bath 10 is located.

[0019] In the following description, unless otherwise specified, the width direction means the width direction of the float bath 10 and the width direction of the glass ribbon GR, and the conveying direction means the conveying direction of the glass ribbon GR.

[0020] (Float Bus) As shown in Fig. 1, a float bath 10 has an inlet 101 at one end (-Y-axis direction) in its longitudinal direction (Y-axis direction) and an outlet 102 at the other end (+Y-axis direction). As shown in Fig. 2, the float bath 10 has a bathtub 11, sidewalls 12, and a ceiling 13. The float bath 10 stores molten metal (e.g., molten tin) M inside, and has an internal space (also simply referred to as space) S formed by the liquid surface of the molten metal M, the sidewalls 12, and the ceiling 13. Note that the internal space S is preferably set to a pressure higher than atmospheric pressure to prevent air from entering through gaps in the sidewalls 12, etc.

[0021] As shown in FIG. 2, the bath 11 is a container with an open top that contains molten metal (for example, molten tin) S.

[0022] As shown in FIGS. 1 and 2, the side wall 12 is installed along the upper outer periphery of the bathtub 11 from the inlet 101 to the outlet 102 of the float bath 10.

[0023] As shown in FIG. 2, the ceiling 13 is connected to the side wall 12 and covers the upper part of the bathtub 11.

[0024] As shown in FIG. 2, the ceiling 13 preferably has gas supply holes 14 for supplying an inert gas or a mixed gas of an inert gas and a reducing gas to the internal space S to prevent oxidation of the molten metal M. Examples of inert gases include nitrogen and argon. Examples of reducing gases include hydrogen. The inert gas or mixed gas is introduced into the internal space S through the gas supply holes 14 and is exhausted to the outside through the outlet 102 of the float bath 10. The gas supply holes 14 may also be provided in the side wall 12.

[0025] The float bath 10 may have a gas exhaust hole in the side wall 12 or the ceiling 13 for exhausting gas from the internal space S, and the inert gas or mixed gas supplied into the internal space S from the gas supply hole 14 may be exhausted from the gas exhaust hole.

[0026] 2, the float bath 10 may have a heater 15, which is a heat source, inserted into the gas supply hole 14. The heater 15 may have a heat generating part 151 at its tip within the internal space S. The heat generating part 151 is preferably disposed above the bath 11.

[0027] In order to adjust the temperature distribution in the float bath 10, a plurality of heaters 15 may be provided at intervals in the conveying direction (Y-axis direction) and width direction (X-axis direction) of the glass ribbon GR shown in Fig. 1 and arranged in a matrix. The output of the heater 15 is controlled so that the temperature of the glass ribbon GR becomes higher toward the upstream side in the flow direction (Y direction) of the glass ribbon GR. In addition, the output of the heater 15 is controlled so that the temperature of the glass ribbon GR becomes approximately uniform in the width direction (X direction).

[0028] The temperature of the bath 11 of the float bath 10 is set by the heater 15 to be equal to or higher than the melting point of the metal (approximately 232°C in the case of tin), and may normally be maintained at 600°C to 1300°C.

[0029] As shown in FIG. 1, when molten glass MG is supplied to the float bath 10 from a glass melting furnace 2 located upstream of the float bath 10, the molten glass MG spreads on the liquid surface (upper surface) of the molten metal M, forming a plate-like molten glass MG.

[0030] As shown in Fig. 1, the interior of the float bath 10 is divided into a supply region L1, which is a low-viscosity region where molten glass MG is supplied, a shaping region L2 downstream of the supply region L1, which spreads the glass ribbon GR flowing on the molten metal M to both the left and right (width direction) and shapes it to a predetermined thickness, and an annealing region L3 between the shaping region L2 and the outlet 102 of the float bath 10, which anneals the glass ribbon GR. The temperature of the glass ribbon GR passing through each of the regions L1 to L3 is adjusted by controlling the amount of heat from a plurality of heaters 15 (see Fig. 2) arranged on a ceiling 13 (see Fig. 2) of each of the regions L1 to L3.

[0031] (support roll) As shown in Fig. 1, a plurality of support rolls 20 are provided so as to pass through the side walls 12 on both sides of the float bath 10. Each support roll 20 is arranged so as to follow the shape of the edge of the glass ribbon GR.

[0032] 2, the support rolls 20 press the widthwise ends of the glass ribbon GR spread on the liquid surface of the molten metal M stored inside the float bath 10 from above, contacting or biting into the surface of the glass ribbon GR, thereby supporting the glass ribbon GR and suppressing shrinkage of the glass ribbon GR in the width direction. When the support rolls 20 rotate around their axes, the rotational force of the support rolls 20 causes the support rolls 20 to pull both widthwise ends of the glass ribbon GR outward, and transport the glass ribbon GR downstream while suppressing shrinkage of the glass ribbon GR in the width direction.

[0033] The support roll 20 may be configured so that the insertion distance from the side wall 12 is adjustable so as to accommodate changes in the width of the glass ribbon GR.

[0034] FIG. 3 is a cross-sectional view of the support roll 20 taken along the axial direction, and FIG. 4 is a front view of the support roll 20 as viewed along the axial direction. The axial direction of the support roll refers to the longitudinal direction of the support roll, and the front of the support roll refers to the annular contact portion 22 side of the support roll 20. As shown in FIG. 3 , the support roll 20 includes an attachment member 21, an annular contact portion 22 that contacts the glass ribbon GR, and a shaft member 23 connected to the rear of the attachment member 21. The attachment member 21 and the annular contact portion 22 are configured to be detachable, and the attachment member 21 and the shaft member 23 are configured as a single unit by, for example, welding. The annular contact portion 22 presses the upper surfaces of both widthwise ends of the glass ribbon GR, contacts or bites into the surface of the glass ribbon GR, and supports the upper surface of the glass ribbon GR, thereby suppressing contraction of the glass ribbon GR in the width direction (the X-axis direction in FIG. 1 ). When the annular contact portion 22 rotates, the glass ribbon GR is transported downstream in the transport direction by the rotational force of the annular contact portion 22.

[0035] 3 and 4 indicate the central axis J of the support roll 20. The central axis J is an axis parallel to the axial direction of the support roll 20, and is the axis that serves as the center when the mounting member 21, the annular contact portion 22, and the shaft member 23 that constitute the support roll 20 are joined together. The central axis J is also the central axis of each of the mounting member 21, the annular contact portion 22, and the shaft member 23.

[0036] The support roll 20 has a refrigerant flow path CL1, which is a refrigerant space, inside it. The refrigerant flow path CL1 will be described in detail later.

[0037] 3, the mounting member 21 is connected to the shaft member 23 at its rear and is integrated with the shaft member 23. The shaft member 23 is driven to rotate by a drive unit 24. When the drive unit 24 is driven, the shaft member 23 rotates, thereby rotating the mounting member 21. The mounting member 21 is detachably attached to the annular abutment portion 22.

[0038] 3, the mounting member 21 has a refrigerant flow path CL11 therein, and the refrigerant flow path CL11 communicates with a refrigerant flow path CL12 of the shaft member 23 with the inner tube of the shaft member 23 inserted into the refrigerant flow path CL11. The mounting member 21 is cooled by the refrigerant flowing through the refrigerant flow path CL11.

[0039] As the coolant, a liquid such as water or oil, or a gas such as air or gas is used.

[0040] The mounting member 21 is preferably fitted into the recess 221 of the annular contact portion 22 so that the cooling flow path CL1 is positioned outside the recess 221.

[0041] The mounting member 21 may be made of a metallic material such as steel or a heat-resistant alloy.

[0042] 3, the mounting member 21 has a shaft portion 211 joined integrally with the shaft member 23, an annular flange portion 212 protruding radially outward from the tip of the shaft portion 211, and a shaft portion 213 provided on a fitting end surface 212a of the flange portion 212 so as to protrude substantially parallel to the central axis of the shaft portion 211. These may be formed integrally, or may be formed by joining separate pieces together.

[0043] The refrigerant flow path CL11 of the mounting member 21 is made up of a refrigerant flow path CL11-1 of the shaft portion 211 and a refrigerant flow path CL11-2 of the flange portion 212, as shown in FIG.

[0044] The shaft portion 211 is integrated with the shaft member 23 by, for example, welding etc. The shaft portion 211 has a refrigerant flow path CL11-1 which communicates with the refrigerant flow path CL12 of the shaft member 23.

[0045] 3, the flange portion 212 is formed at the tip end portion of the shaft portion 211 (the end portion opposite the shaft member 23) so as to be larger radially outward than the shaft portion 211. The flange portion 212 has a refrigerant flow path CL11-2, which communicates with the refrigerant flow path CL11-1. The refrigerant flow path CL11-2 is formed to have a larger space radially outward than the refrigerant flow path CL11-1.

[0046] The flange portion 212 has a fitting end surface 212 a on the annular contact portion 22 side, which contacts the recess 221 of the annular contact portion 22 .

[0047] The shaft portion 213 is provided on the fitting end surface 212a of the flange portion 212, substantially parallel to the central axis of the shaft portion 211. As shown in Fig. 4, a plurality of shaft portions 213 (four in Fig. 4) may be provided at substantially equal intervals around the central axis of the flange portion 212. The shaft portions 213 allow the mounting member 21 and the annular abutment portion 22 to rotate together.

[0048] 3 and 4, the shaft portion 213 passes through the insertion hole 22b of the annular contact portion 22 and has a male thread on its side surface. A nut 27 screwed onto the male thread and the flange portion 212 limit the axial movement of the annular contact portion 22. The mounting member 21 can be removed from the annular contact portion 22 by removing the nut 27 from the male thread.

[0049] 2, the mounting member 21 is disposed in the internal space S of the float bath 10, and receives a large torque when it receives a rotational driving force from the drive unit 24. For this reason, the mounting member 21 is preferably made of a material that is heat-resistant, corrosion-resistant, and rigid. Examples of materials that can be used to form such mounting member 21 include lightweight metal materials such as aluminum alloys and titanium alloys, and stainless steel.

[0050] 3, annular abutment portion 22 does not have a refrigerant flow path therein, is formed in a cap shape, and has a mounting surface 22a located on the mounting member 21 side, with a recess 221 into which mounting member 21 can be fitted. Annular abutment portion 22 fits mounting member 21 into recess 221 so that the central axis of shaft member 23 of mounting member 21 and the central axis of insertion hole 22b of annular abutment portion 22 are substantially on the same line.

[0051] As shown in FIG. 5, the recess 221 is formed so that its depth H1 is equal to or greater than the thickness H2 of the fitting end face 212a of the mounting member 21. That is, as shown in FIG. 3, in a side view of the annular abutment portion 22, the recess 221 is formed so as to surround the fitting end face 212a and a portion of the outer periphery 212b of the mounting member 21 but not the entire outer periphery 212b of the mounting member 21, including the cooling channel CL1. If the depth H1 (see FIG. 5) of the recess 221 is equal to or greater than the thickness H2 (see FIG. 5) of the fitting end face 212a, when the mounting member 21 is fitted into the recess 221, only the fitting end face 212a and a portion of the outer periphery 212b of the mounting member 21 are covered by the recess 221. In this case, cooling of the annular abutment portion 22 by the refrigerant flowing through the refrigerant channel CL11 in the flange portion 212 is suppressed.

[0052] 2 and 3 , the annular abutment portion 22 contacts the upper surface of the glass ribbon GR at the outer circumferential portion 222. When the drive unit 24 is rotationally driven, the mounting member 21 rotates, and the annular abutment portion 22 rotates. The glass ribbon GR is moved in the conveying direction by the rotational action of the annular abutment portion 22.

[0053] As shown in FIG. 4, the annular abutment portion 22 has gear-shaped protrusions (uneven portions) 222a on its outer periphery 222. The shape of the protrusions of the uneven portions 222a is not particularly limited, but may be formed in a mountain shape (for example, a quadrangular pyramid shape). The uneven portions 222a make it easier for the annular abutment portion 22 to bite into the glass ribbon GR. The uneven portions 222a bite into the surface of the glass ribbon GR, thereby suppressing idling of the support roll 20, and the support roll 20 can transport the glass ribbon GR downstream while stretching it. Furthermore, since the annular abutment portion 22 has the uneven portions 222a on its outer periphery, the surface area of ​​the outer periphery of the support roll 20 is increased, thereby enhancing the cooling effect of the support roll 20 by air cooling.

[0054] The uneven portion 222a is formed in a mountain shape when viewed from the front of the annular abutment portion 22 as shown in FIG. 4, but the shape of the uneven portion 222a when viewed from the front of the annular abutment portion 22 may be formed, for example, in a rectangular shape, a trapezoidal shape, or the like, or may be formed in a wavy shape as shown in FIG. 6.

[0055] The cross-sectional shape of the uneven portion 222a of the annular contact portion 22 in a side view is formed in a mountain shape as shown in FIG. 5, but it may also be formed in, for example, a square shape, a trapezoidal shape, or a wavy shape as shown in FIG. 7.

[0056] 8, the outer peripheral portion 222 may be formed flat without having the uneven portion 222a. Also, as shown in Fig. 9, the outer peripheral portion 222 may be formed so that its cross-sectional shape is curved convexly outward in the radial direction over the entire circumference.

[0057] As shown in Fig. 4, the annular contact portion 22 is formed in a circular shape when viewed from the front, but may be formed in a polygonal shape or the like. For example, as shown in Fig. 10, the annular contact portion 22 may be formed in a rectangular shape when viewed from the front. Even when the annular contact portion 22 is formed in a polygonal shape or the like when viewed from the front, the shape of the uneven portion 222a of the annular contact portion 22 when viewed from the front may be formed in, for example, a rectangular shape, a trapezoidal shape, a wavy shape, or the like, as described above. Furthermore, the cross-sectional shape of the uneven portion 222a of the annular contact portion 22 when viewed from the side may also be formed in, for example, a rectangular shape, a trapezoidal shape, a wavy shape, or the like, as described above.

[0058] As shown in FIG. 3, the uneven portions 222a are formed in four rows on the outer circumferential portion 222 of the annular contact portion 22, but they may be formed in one to three rows, or five or more rows.

[0059] 3, the annular contact portion 22 has insertion holes 22b. The shaft portions 213 are inserted through the insertion holes 22b. The inner diameter of each insertion hole 22b is preferably larger than the outer diameter of the corresponding shaft portion 213.

[0060] The annular contact portion 22 is detachably mechanically joined to the mounting member 21 by screwing the shaft portion 213 with a nut 27 to the surface 22c located inside the float bath 10. If the mechanical joining is by screwing or the like, the mounting member 21 and the annular contact portion 22 are detachable, so if the annular contact portion 22 becomes worn, the annular contact portion 22 can be removed from the mounting member 21 and replaced with a new annular contact portion 22. Note that as a method of mechanical joining, other methods such as screwing or fixing with a fastening member may also be used.

[0061] The annular contact portion 22 is preferably made of a material including metals such as steel and heat-resistant alloys, ceramics, graphite, carbon fiber, etc. These may be used alone or in combination of two or more.

[0062] The ceramic is not particularly limited, but examples thereof include silicon carbide (SiC) and silicon nitride (Si3N4).

[0063] Ceramics containing Si3N4 (Si3N4-based ceramics) can be produced by sintering a compact made from a powder mixture containing silicon nitride powder and a sintering aid powder. Sintering methods include atmospheric sintering and pressure sintering (including hot press sintering and gas pressure sintering). The sintering aid can be at least one selected from the group consisting of alumina (Al2O3), magnesia (MgO), titania (TiO2), zirconia (ZrO2), and yttria (Y2O3).

[0064] The Si3N4 ceramic preferably has an aluminum (Al) content of 0.1% by mass or less, preferably less than 1% by mass, a magnesium (Mg) content of 0.7% by mass or less, preferably less than 0.7% by mass, and a titanium (Ti) content of 0.9% by mass or less, preferably less than 0.9% by mass. When the Al content, Mg content, and Ti content are within the above ranges, the annular abutment portion 22 is less likely to react with the glass ribbon GR and the glass ribbon GR is less likely to adhere to it, thereby providing good durability. Note that the Al content, Mg content, and Ti content may each be 0% by mass.

[0065] The Si3N4 ceramics preferably has a zirconium (Zr) content of 3.5 mass% or less, preferably less than 3.5 mass%, and an yttrium (Y) content of 0.5 mass% or more, preferably more than 0.5 mass%, and 10 mass% or less, preferably less than 10 mass%. Zr and Y are components that are less likely to interdiffuse with the glass ribbon GR than Al, Mg, and Ti, and therefore may be contained within the above ranges. By being contained within the above ranges, sintering of the silicon nitride powder can be promoted. Note that Zr is an optional component, and the Zr content may be 0 mass%.

[0066] The SiN ceramic of this embodiment is a sintered body obtained by atmospheric sintering or pressure sintering, but may also be a sintered body obtained by reactive sintering. Reactive sintering is a method in which a compact made of metal silicon (Si) powder is heated in a nitrogen atmosphere. Since reactive sintering does not use a sintering aid, a high-purity sintered body can be obtained, and the durability of the sintered body against the glass ribbon GR can be improved.

[0067] Of the above-mentioned metals, ceramics, graphite, carbon fiber, etc., graphite is more preferable as a material for forming the annular abutment portion 22, as it is less susceptible to cooling and improves the heat resistance, corrosion resistance, and rigidity of the annular abutment portion 22.

[0068] Since the annular abutment portion 22 contains graphite, it is possible to improve heat resistance, corrosion resistance, and rigidity. As a result, the annular abutment portion 22 can be disposed in the internal space S of the float bath 10, which is in a harsh environment, similar to the mounting member 21, as shown in FIG. 2. Furthermore, since the annular abutment portion 22 contains graphite, it is possible to improve thermal insulation. Therefore, even if the annular abutment portion 22 comes into direct contact with the glass ribbon GR, cooling of the glass ribbon GR is suppressed. Furthermore, since graphite has higher thermal insulation properties than metal materials, the cold of the mounting member 21, which is cooled by the refrigerant flowing through the cooling flow path CL1 (see FIG. 3), described later, is unlikely to be transmitted to the glass ribbon GR via the annular abutment portion 22. Therefore, when the annular abutment portions 22 of the support roll 20 are brought into contact with the surfaces of both ends in the width direction of the glass ribbon GR and the glass ribbon GR is pulled outward in both width directions and supported, the glass ribbon GR is prevented from solidifying, and the glass ribbon GR can be easily adjusted to a desired thickness and width. Furthermore, the insulating effect of graphite makes it difficult for localized low-temperature regions to occur within the float bath 10, thereby reducing the possibility that tin compounds volatilized from the surface of the molten metal M will aggregate and fall onto the glass ribbon GR. Furthermore, graphite has low wettability with respect to the molten metal M. Therefore, even if the molten metal M splashes and adheres to the glass ribbon GR while the glass ribbon GR is being pulled by the support rolls 20, the annular contact portion 22 is unlikely to become wet with the molten metal M, and therefore there is little risk that the support rolls 20 will entangle the glass ribbon GR.

[0069] When the annular contact portion 22 is made of a material containing graphite, the graphite content of the annular contact portion 22 is preferably 50 wt % or more. If the content is 50 wt % or more, the annular contact portion 22 can exhibit the properties of graphite, such as excellent heat insulation and low wettability with respect to the molten metal M.

[0070] When the annular abutment portion 22 is made of a material containing graphite, the annular abutment portion 22 is manufactured, for example, by filling a mold with carbon powder, which is the raw material for graphite, and then pressure-molding the molded product and graphitizing it through heat treatment. Alternatively, the annular abutment portion 22 can be manufactured by producing a block of graphite through pressure-molding and graphitizing the carbon powder, and then cutting the block into the shape of the annular abutment portion 22. The carbon powder, which is the raw material for graphite, may contain other components such as reinforcing materials, additives, and mold release agents.

[0071] The annular contact portion 22 may be provided with a heat insulating material on the fitting end surface 212a of the mounting member 21, which is prone to becoming low in temperature. This makes it difficult for cold heat from the fitting end surface 212a of the mounting member 21 to be transferred to the internal atmosphere of the float bath 10, making it difficult for local low-temperature regions to occur within the float bath 10, thereby stabilizing the ambient temperature within the float bath 10 and reducing heat loss. Furthermore, by making it difficult for local low-temperature regions to occur within the float bath 10, it is possible to reduce the possibility of tin compounds volatilized from the surface of the molten metal M coagulating on the support roll 20 and falling onto the glass ribbon GR.

[0072] The material forming the heat insulating material preferably has excellent heat resistance and corrosion resistance in addition to heat insulation. Examples of such heat insulating materials include ceramics and carbon. The heat insulating material may be attached to the mounting member 21, or a heat-resistant material such as zirconia may be sprayed onto the fitting end surface 212a of the mounting member 21.

[0073] In this embodiment, the support roll 20 may have a plurality of annular contact portions 22 arranged in series.

[0074] In this embodiment, in addition to the annular contact portion 22, the support roll 20 may have one or more other annular contact portions arranged in series along the axial direction of the shaft member 23. The other annular contact portions may have the same configuration as the annular contact portion 22, or may have a different configuration. For example, as shown in FIG. 11 , the support roll 20 may have an annular contact portion 31 adjacent to the annular contact portion 22, and the annular contact portion 31 may be provided so that a mounting surface 31 a facing the surface 22 c of the annular contact portion 22 comes into contact with the annular contact portion 22.

[0075] The annular contact portion 31 may have the same configuration as the annular contact portion 22, except that it does not have the recess 221. Like the annular contact portion 22, the annular contact portion 31 may be formed in a disk shape without having a refrigerant flow path therein. The annular contact portion 31 may be provided so that the central axis of the shaft member 23 of the mounting member 21 and the central axis of the annular contact portion 31 are substantially collinear. The annular contact portion 31 has gear-shaped protrusions (concave and recess portions) 311a on its outer circumferential portion 311, and has an insertion hole 31b through which the shaft portion 213 is inserted. The insertion hole 31b is preferably provided at a position corresponding to the insertion hole 22b of the annular contact portion 22. The concave and recess portions 311a and the insertion hole 31b may have the same configuration as the concave and recess portions 222a and the insertion hole 22b of the annular contact portion 22. In addition, in Figure 11, the annular abutment portion 22 and the annular abutment portion 31 may be detachably joined to the mounting member 21 by screwing the shaft portion 213 with a nut 27 to the surface 31c of the annular abutment portion 31 located inside the float bath 10.

[0076] 12, the support roll 20 may be provided with an annular contact portion 31 such that its mounting surface 31a is spaced a predetermined distance from the annular contact portion 22. In this case, the annular contact portion 31 may also be detachably joined to the mounting member 21 by screwing the mounting surface 31a to the shaft portion 213 with a nut 27.

[0077] As shown in Fig. 3, the shaft member 23 is integrally joined to the shaft portion 211 of the mounting member 21 and has a refrigerant flow path CL12 therein. The shaft member 23 is a double pipe consisting of an inner pipe and an outer pipe. The refrigerant flow path CL12 is formed by an inner space S11 of the inner pipe and a space S12 formed between the outer peripheral surface of the inner pipe and the inner peripheral surface of the outer pipe. The shaft member 23 is cooled by the refrigerant flowing through the refrigerant flow path CL12.

[0078] The shaft member 23 may be made of a metallic material such as steel or a heat-resistant alloy.

[0079] A heat insulating material (not shown) may be wound around the outer periphery of the shaft member 23. The heat insulating material may be the same as the heat insulating material used for the annular contact portion 22.

[0080] 3, the shaft member 23 passes through the annular contact portion 22 and is connected to a drive unit 24, which is composed of a motor, a reducer, etc., outside the float bath 10. When the drive unit 24 is operated, the shaft member 23, the mounting member 21, and the annular contact portion 22 rotate integrally around the central axis J of the shaft member 23.

[0081] As described above, the support roll 20 has the refrigerant flow path CL1 inside. The refrigerant flow path CL1 is made up of the refrigerant flow path CL11 in the mounting member 21 and the refrigerant flow path CL12 in the shaft member 23. The support roll 20 is cooled by the refrigerant flowing through the refrigerant flow path CL1.

[0082] The refrigerant flow path CL1 is provided inside the mounting member 21 and the shaft member 23 over the entire axial length. The refrigerant flow path CL1 is connected to a refrigerant supply / discharge unit 26 for supplying and discharging the refrigerant. As the shaft member 23 is rotationally driven by the drive unit 24, the refrigerant is forced from the refrigerant supply / discharge unit 26 into the inner space S11 of the inner pipe within the shaft member 23. The refrigerant then flows from the inner space S11 of the inner pipe into the refrigerant flow path CL11 inside the mounting member 21 and circulates through the refrigerant flow path CL11-2 in the flange portion 212. At this time, heat is exchanged between the refrigerant and the annular abutment portion 22. However, as will be described later, the mounting member 21 is provided in the recess 221 of the annular abutment portion 22 so as not to surround the refrigerant flow path CL1. Therefore, the surface 22c of the annular abutment portion 22 located inside the float bath 10 is hardly cooled. The refrigerant that has absorbed heat from the annular contact portion 22 returns to the refrigerant supply / discharge portion 26 via the refrigerant flow path CL11-2 in the flange portion 212, the refrigerant flow path CL11-1 in the shaft portion 211, and the space S12 formed between the outer peripheral surface of the inner pipe and the inner peripheral surface of the outer pipe of the shaft member 23, and is then discharged to the outside. The refrigerant discharged to the outside may be cooled by a cooler and returned to the inner space S11 of the inner pipe again. Note that the refrigerant flow direction may be reversed.

[0083] In FIG. 3, the refrigerant flow path CL1 is formed so that the refrigerant flows linearly through the shaft member 23 and the mounting member 21. However, to increase the cooling water flow area, the refrigerant may be formed, for example, in a spiral shape. In this case, the cooling efficiency is improved, thereby reducing the amount of water flowing through the refrigerant flow path CL1. The refrigerant may also be circulated through the refrigerant flow path CL1. For example, in the refrigerant supply / discharge unit 26, a circulation path is formed by connecting the water supply side flow path and the water discharge side flow path with a circulation pump, and a chiller is installed along the circulation path as needed. In this case, there is no need to connect piping for supplying and discharging the refrigerant to the glass sheet forming apparatus 1, making it easier to construct the equipment. In addition, it is preferable to use a fluid such as oil or gas as the refrigerant for the refrigerant flow path CL1. In this case, the mounting member 21 and the shaft member 23 are not exposed to moisture, thereby suppressing corrosion from within the support roll 20.

[0084] As described above, the support roll 20 includes the mounting member 21 and the annular contact portion 22. The annular contact portion 22 has a recess 221, and the depth H1 of the recess 221 is equal to or greater than the thickness H2 of the fitting end face 212a of the mounting member 21. The support roll 20 is fitted into the mounting member 21 so that the recess 221 surrounds the end of the mounting member 21. This prevents the annular contact portion 22 from being cooled by the cooling flow path CL1 in the mounting member 21, thereby preventing localized cooling of the molten metal M, such as molten tin, present near the annular contact portion 22. Therefore, the support roll 20 can reduce the accumulation of deposits on the surface 22c of the annular contact portion 22, which is caused by products volatilized from the surface of the molten metal M, such as molten tin, coagulating on the surface 22c of the annular contact portion 22.

[0085] The support roll 20 can suppress the accumulation of deposits on the surface 22c of the annular contact portion 22, and therefore can suppress the deposits from becoming large and falling onto the surface of the glass ribbon GR flowing inside the float bath 10 during use due to the weight of the large deposits or the rotation of the support roll 20.

[0086] Furthermore, the support roll 20 can prevent excessive cooling of the annular contact portion 22 by the cooling flow path CL1 in the mounting member 21, and therefore the glass ribbon GR can be easily adjusted to a desired thickness and width.

[0087] Furthermore, since the mounting member 21 of the support roll 20 can be easily attached and detached from the recess 221, the support roll 20 can be easily replaced and maintained.

[0088] The support roll 20 can fit the mounting member 21 into the recess 221 so that the cooling flow path CL1 is located outside the recess 221. This more reliably prevents the annular contact portion 22 from being cooled, and the support roll 20 can further reduce the accumulation of deposits on the surface 22c of the annular contact portion 22.

[0089] The annular contact portion 22 of the support roll 20 can be made of a material containing graphite. The insulating effect of the graphite enhances the insulating effect of the annular contact portion 22, making it less likely that a localized low-temperature region will occur within the float bath 10. This makes it less likely that metal compounds volatilized from the surface of the molten metal M will aggregate on the surface 22c of the annular contact portion 22. Therefore, the support roll 20 can further reduce the accumulation of deposits on the surface 22c of the annular contact portion 22. The support roll 20 can reduce the amount of deposits that adhere to the surface 22c, thereby reducing the amount of deposits that fall onto the glass ribbon GR. Furthermore, the annular contact portion 22 has improved heat resistance, corrosion resistance, and rigidity, allowing it to be stably disposed in the internal space S of the float bath 10. Furthermore, since the annular contact portion 22 can have improved insulating properties, even if the annular contact portion 22 directly contacts the glass ribbon GR, the insulating effect of the graphite prevents the glass ribbon GR from being cooled more than necessary. Therefore, the annular abutment portion 22 can suppress the transfer of cold heat from the mounting member 21 cooled by the cooling flow path CL1 to the glass ribbon GR. Therefore, the support roll 20 suppresses solidification of the glass ribbon GR while the annular abutment portions 22 of the support roll 20 support the surfaces of both ends in the width direction of the glass ribbon GR, and the glass ribbon GR can be easily adjusted to have a desired thickness and width.

[0090] The composition of the glass sheet G to be formed is not particularly limited, but may contain, for example, in mass percentage on an oxide basis, 50 to 75% SiO, 0.1% to 24% AlO, 0% to 12% BO, 0% to 10% MgO, 0% to 14.5% CaO, 0% to 24% SrO, 0% to 13.5% BaO, 0% to 20% NaO, 0% to 20% KO, 0% to 5% ZrO, 5% to 29.5% MgO+CaO+SrO+BaO, and 0% to 20% NaO+K2O.

[0091] The type of glass plate is not particularly limited, but may be, for example, alkali-free glass. Alkali-free glass is glass that does not substantially contain alkali metal oxides (Na2O, K2, Li2). The total content of alkali metal oxides in the alkali-free glass (Na2O + K2O + Li2O) may be, for example, 0.1% or less.

[0092] The alkali-free glass contains, for example, in terms of mass percentage on an oxide basis, SiO2: 50 to 73%, preferably 50 to 66%, Al2O3: 10.5 to 24%, B2O3: 0 to 12%, MgO: 0 to 10%, preferably 0 to 8%, CaO: 0 to 14.5%, SrO: 0 to 24%, BaO: 0 to 13.5%, ZrO2: 0 to 5%, and MgO + CaO + SrO + BaO: 8 to 29.5%, preferably 9 to 29.5%.

[0093] When alkali-free glass has a high strain point and solubility is a consideration, it preferably contains, in mass percentage on an oxide basis, 58-66% SiO2, 15-22% Al2O3, 5-12% B2O3, 0-8% MgO, 0-9% CaO, 3-12.5% ​​SrO, and 0-2% BaO, or 9-18% MgO+CaO+SrO+BaO.

[0094] When a high strain point is taken into consideration, the alkali-free glass preferably contains, expressed as mass percentages on an oxide basis, 54 to 73% SiO2, 10.5 to 22.5% Al2O3, 0 to 5.5% B2O3, 0 to 10% MgO, 0 to 9% CaO, 0 to 16% SrO, 0 to 2.5% BaO, or 8 to 26% MgO+CaO+SrO+BaO.

[0095] In this way, since the glass sheet shaping apparatus 1 includes the support roll 20, it is possible to suppress the accumulation of deposits on the surface 22c of the annular contact portion 22. Therefore, the glass sheet shaping apparatus 1 can suppress the deposits from falling onto the surface of the glass ribbon GR flowing inside the float bath 10 during use due to the weight of the deposits or the rotation of the support roll 20. This prevents the glass ribbon GR at the position where the deposits have fallen from becoming unusable, and suppresses a decrease in the yield of glass sheets G produced relative to the amount of molten glass MG used. Therefore, the glass sheet shaping apparatus 1 can improve the yield of molten glass MG, and therefore the production efficiency of glass sheets G.

[0096] <Glass sheet forming method> The glass sheet forming method according to this embodiment will be described. In the glass sheet forming method according to this embodiment, a glass sheet forming apparatus to which the support roll according to this embodiment described above is applied is used.

[0097] In the glass sheet forming method according to this embodiment, molten glass MG is supplied onto the surface of molten metal M in the float bath 10, and is moved within the float bath 10 to form a ribbon-shaped glass flow (glass ribbon) GR (glass ribbon formation process: step S11).

[0098] Molten glass MG is poured into the float bath 10 from an inlet 101 on the upstream side of the float bath 10, and the molten glass MG is allowed to flow downstream while floating on molten tin metal M stored in the float bath 10, thereby forming a belt-like glass ribbon GR.

[0099] Next, using multiple support rolls 20, both ends of the glass ribbon GR in the width direction perpendicular to the conveying direction are pressed from above the glass ribbon GR to support the glass ribbon GR, and the glass ribbon GR is conveyed downstream in the conveying direction (conveying process: step S12).

[0100] Within the float bath 10, a plurality of support rolls 20 are brought into contact with the upper surfaces of the widthwise ends of the glass ribbon GR to press them, and the support rolls 20 are rotated while pulling both widthwise ends outward, thereby transporting the glass ribbon GR downstream. The glass ribbon GR is cooled and solidified while being transported downstream, and is then carried out as a glass sheet G from an outlet 102 on the downstream side.

[0101] In this manner, in the glass sheet forming apparatus 1, the molten glass MG is formed into a glass sheet G via a glass ribbon GR inside the float bath 10.

[0102] The glass sheet G is pulled up from the molten metal M by the lift-out rolls and is annealed in an annealing furnace (not shown) provided downstream of the glass sheet forming device 1 to become a glass sheet. After being carried out of the annealing furnace (not shown), the glass sheet is cut into a predetermined size and shape by a cutting machine (not shown) to become a glass product such as a glass sheet.

[0103] The glass sheet forming method according to this embodiment uses support rolls 20 in a glass sheet forming apparatus 1 when forming a glass sheet G from a glass ribbon GR inside a float bath 10. This suppresses the accumulation of deposits on the surface 22c of the annular contact portion 22 of the support rolls 20. Therefore, the glass sheet forming method according to this embodiment can suppress the deposits from falling onto the surface of the glass ribbon GR flowing inside the float bath 10 during use due to the weight of the deposits or the rotation of the support rolls 20. This prevents the glass ribbon GR at the position where the deposits have fallen from becoming unusable, and suppresses a decrease in the yield of glass sheets G produced relative to the amount of molten glass MG used. Therefore, the glass sheet forming method according to this embodiment can improve the yield of molten glass MG, thereby improving the production efficiency of glass sheets G.

[0104] As described above, the glass plate forming apparatus 1 of this embodiment and the glass plate forming method of this embodiment can increase the production efficiency of glass plates G, and can therefore be suitably used for manufacturing glass plates used, for example, for flat panel displays such as liquid crystal displays (LCDs), plasma displays (PDPs), and organic EL displays, solar panels, window glass for buildings, etc.

[0105] Although the embodiments have been described above, they are presented as examples and the present invention is not limited to the above embodiments. The above embodiments can be implemented in various other forms, and various combinations, omissions, substitutions, modifications, etc. can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the inventions and their equivalents as set forth in the claims. [Explanation of symbols]

[0106] 1. Glass plate forming equipment 10. Float Bath 20 Support Roll 21 Mounting material 22 Annular contact part 23 Shaft member M Molten metal MG molten glass GR Glass Ribbon G Glass plate

Claims

1. A support roll for supporting a band-shaped glass ribbon, a mounting member having a cooling channel therein; an annular abutment portion having a recess into which an end of the mounting member is fitted; Equipped with The depth of the recess is equal to or shallower than the thickness of the member including the fitting end surface of the mounting member that contacts the bottom surface of the recess, the cooling flow path is provided so as to be in contact with a member including the fitting end surface, The mounting member is a support roll that is fitted into the recess so that the cooling flow path is positioned outside the recess.

2. 2. The support roll according to claim 1, wherein the annular contact portion contains at least one component selected from the group consisting of graphite, metal, ceramics, and carbon fiber.

3. a float bath in which a glass ribbon formed by floating molten glass on the upper surface of molten metal stored therein is transported; support rolls that support the glass ribbon by pressing widthwise ends of the glass ribbon from above and suppress shrinkage of the glass ribbon in the width direction; Equipped with The glass sheet forming apparatus, wherein the support roll is the support roll according to claim 1 or 2.

4. a glass ribbon forming step of supplying molten glass onto a surface of molten metal in a float bath and forming a glass ribbon while moving the molten glass within the float bath; A conveying step of conveying the glass ribbon while supporting the glass ribbon by pressing widthwise ends of the glass ribbon from above using a plurality of top rolls; Including, The top roll comprises an attachment member having a cooling flow path therein and an annular abutment portion having a recess into which an end of the attachment member is fitted, The depth of the recess is equal to or shallower than the thickness of the member including the fitting end surface of the mounting member that contacts the bottom surface of the recess, the cooling flow path is provided so as to be in contact with a member including the fitting end surface, The method for forming a glass sheet, wherein the mounting member is fitted into the recess so that the cooling flow path is positioned outside the recess.

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