Forming device

Abstract

A molding device for molding glass ribbon. The molding device has an axial direction that extends from a first end part to a second end part, the first end part being on an entry side for molten glass. First and second protruding parts extend from the first end part to the second end part at an upper part of the molding device. Molten glass flows from the first end part toward the second end part along a channel that is formed between the protruding parts. As seen from above, when the channel width of the channel is the direction that is orthogonal to the axial direction, the channel width of the channel near the second end part continuously decreases toward the second end part to become 0 (zero) at the second end part.

Description

[Technical Field]

[0001] The present invention relates to forming devices, and more particularly to forming devices used in the manufacture of glass sheets. [Background technology]

[0002] The down-draw method is known as one type of continuous manufacturing process for glass sheets, and a representative example of the down-draw method is the fusion method (for example, Patent Document 1).

[0003] In this fusion method, molten glass obtained by melting glass raw materials is supplied to a channel provided at the top of a forming device (hereinafter referred to as a "forming device"). The forming device has a cross section that is roughly wedge-shaped with a downward point, and the molten glass that overflows from the channel flows down along two opposing side surfaces of the forming device.

[0004] The molten glass flowing down along both sides of the glass forming device joins and integrates at the bottom end of the forming device, thereby forming a glass ribbon. This glass ribbon is then pulled downward by pulling members such as rollers while being slowly cooled, and cut to a predetermined size. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] U.S. Patent No. 3,338,696 Summary of the Invention [Problem to be solved by the invention]

[0006] When a glass ribbon is formed using the above-described forming apparatus, problems may arise, such as crystallization (i.e., devitrification) occurring in a portion of the glass ribbon or local changes in the glass composition. In addition, a problem of a non-uniform thickness being obtained in the width direction of the glass ribbon may often occur.

[0007] The present invention has been made in consideration of the above background, and aims to provide a molding device that is less likely to cause devitrification or composition changes when molding a glass ribbon, and that can suppress thickness variations in the width direction of the glass ribbon. [Means for solving the problem]

[0008] The present invention provides a forming apparatus for forming a glass ribbon, comprising: The glass tube has an axial direction extending from a first end to a second end, the first end being an inlet side for molten glass, the forming device has first and second protrusions on an upper portion thereof extending from the first end to the second end, and a channel through which the molten glass flows from the first end to the second end is formed between the protrusions; A molding device is provided in which, when viewed from above, the channel width in a direction perpendicular to the axial direction of the channel is defined as the channel width, and the channel width near the second end of the channel continuously decreases toward the second end, reaching 0 (zero) at the second end. [Effects of the Invention]

[0009] The present invention can provide a forming device that is less likely to cause devitrification or composition changes during forming of a glass ribbon and that can suppress thickness variations in the width direction of the glass ribbon. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram showing a schematic configuration of a conventional molding device used in a fusion method. [Figure 2] FIG. 2 is a diagram schematically illustrating the top surface of the molding device illustrated in FIG. [Figure 3] FIG. 3 is a diagram schematically illustrating a cross section of the molding device shown in FIG. 2 taken along line II. [Figure 4] 1 is a top view schematically illustrating the flow direction at each position of molten glass flowing within a channel of a conventional forming device. [Figure 5] 1 is a perspective view schematically illustrating an example of the configuration of a molding device according to an embodiment of the present invention. [Figure 6] FIG. 6 is a diagram schematically illustrating the top surface of the molding apparatus according to one embodiment of the present invention shown in FIG. 5. [Figure 7] 7 is a diagram showing a schematic cross section of the molding device according to one embodiment of the present invention shown in FIG. 6 taken along line II-II. [Figure 8] 2 is a top view schematically illustrating the flow direction at each position of molten glass flowing through a channel of a forming device according to one embodiment of the present invention. FIG. [Figure 9] FIG. 10 is a perspective view schematically showing an example of the configuration of another molding device according to an embodiment of the present invention. [Figure 10] FIG. 10 is a diagram schematically illustrating the top surface of the molding device shown in FIG. [Figure 11] 11 is a diagram schematically illustrating a cross section of the molding device shown in FIG. 10 taken along line III-III. [Figure 12] 3 is a top view schematically illustrating the flow direction at each position of molten glass flowing through a channel of another forming device according to one embodiment of the present invention. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, a molding apparatus according to an embodiment of the present invention will be described with reference to the drawings.

[0012] (Conventional molding equipment) To better understand the configuration and features of the molding apparatus according to one embodiment of the present invention, first, a brief description of the configuration of a conventional molding apparatus will be given with reference to FIGS. 1 to 3. FIG.

[0013] Figure 1 shows a schematic diagram of a molding apparatus used in a conventional fusion method. Figure 2 shows a schematic top view of the molding apparatus shown in Figure 1. Figure 3 shows a schematic cross section of the molding apparatus shown in Figure 2 taken along line II. Figures 1 and 3 show the molding apparatus in use.

[0014] As shown in Figures 1 to 3, the conventional molding apparatus 1 has an axial direction (X direction) extending from a first end 3 to a second end 5, and the first end 3 is connected to a supply pipe 7 for molten glass.

[0015] 3, the molding device 1 has a cross section perpendicular to the axial direction that has a generally wedge-shaped outline, and has two opposing outer surfaces 8a and 8b. The outer surfaces 8a and 8b meet at a joining edge 9.

[0016] The molding device 1 has an upper first portion 11 and a lower second portion 31 .

[0017] The first portion 11 of the molding apparatus 1 has two protrusions 12a and 12b that face each other. The protrusion 12a has an upper surface 13a, an inner surface 14a, and an outer surface 15a. The inner surface 14a and the outer surface 15a each extend along the vertical direction (Z direction) and face each other. The inner surface 14a and the outer surface 15a are connected by the upper surface 13a. Similarly, the protrusion 12b has an upper surface 13b, an inner surface 14b, and an outer surface 15b.

[0018] Furthermore, the first portion 11 of the molding device 1 has a bottom surface 17 between the two protrusions 12a and 12b. The bottom surface 17 is configured to gradually decrease in depth from the first end 3 to the second end 5 of the molding device 1.

[0019] Inner surface 14a of protrusion 12a, inner surface 14b of protrusion 12b, and bottom surface 17 define a channel 22 in first portion 11. Due to the shape of bottom surface 17, channel 22 is configured such that its depth gradually decreases from first end 3 toward second end 5 of molding apparatus 1, reaching zero depth near second end 5.

[0020] Meanwhile, the second portion 31 of the molding apparatus 1 has outer surfaces 33a and 33b facing each other. The outer surface 33a of the second portion 31 is connected to the outer surface 15a of the first portion 11, thereby constituting the outer surface 8a of the molding apparatus 1. Similarly, the outer surface 33b of the second portion 31 is connected to the outer surface 15b of the first portion 11, thereby constituting the outer surface 8b of the molding apparatus 1.

[0021] When the conventional forming apparatus 1 is used, molten glass MG is supplied to the forming apparatus 1 through the supply pipe 7 .

[0022] Molten glass MG supplied to the forming apparatus 1 flows through the channel 22 from the first end 3 to the second end 5 .

[0023] The molten glass MG supplied to the channel 22 then overflows from the protruding portions 12a and 12b of the first portion 11 of the forming apparatus 1 along the respective outer surfaces 15a and 15b, and flows downward.

[0024] As a result, as shown in FIG. 3, a first molten glass portion 40a is formed on outer surface 15a of first part 11 of molding device 1, and a second molten glass portion 40b is formed on outer surface 15b of first part 11.

[0025] Thereafter, first molten glass portion 40a flows further downward along outer surface 33a of second section 31 of forming apparatus 1. Similarly, second molten glass portion 40b flows further downward along outer surface 33b of second section 31 of forming apparatus 1.

[0026] As a result, first molten glass portion 40a and second molten glass portion 40b reach joining side 9 and are integrated therein, thereby forming glass ribbon GR.

[0027] Thereafter, the glass ribbon GR is further stretched in the vertical direction and slowly cooled.

[0028] In the conventional fusion process, a glass ribbon GR and then a glass sheet are produced in this manner.

[0029] Here, in the conventional forming apparatus 1, problems such as devitrification occurring in a part of the glass ribbon GR and local changes in the glass composition have often been observed during forming of the glass ribbon GR. Also, a problem that a uniform thickness cannot be obtained in the width direction of the glass ribbon GR (the X direction in FIG. 1 ) has often been reported.

[0030] In order to address these problems, the inventors of the present application have conducted extensive research into the causes of the devitrification, composition change, and thickness non-uniformity of the glass ribbon GR, and have discovered that these problems are caused by the structure of the channel 22.

[0031] 1, in the conventional forming apparatus 1, a blocking wall 50 is provided on the tip side of the channel 22, i.e., on the second end 5 side of the forming apparatus 1. This blocking wall 50 is provided to restrict the flow of the molten glass MG in the axial direction (X direction) and to prevent the molten glass MG flowing along the axial direction from proceeding beyond a predetermined distance.

[0032] However, such blocking walls 50 may adversely affect the flow of molten glass MG within the channel 22 .

[0033] The influence of the blocking wall 50 will be described below with reference to FIG.

[0034] Fig. 4 is a schematic top view of a portion of channel 22 of conventional forming apparatus 1. Fig. 4 also shows a schematic flow direction of molten glass MG flowing in channel 22 at each position.

[0035] As shown in FIG. 4, the molten glass MG supplied from the first end 3 of the forming apparatus 1 to the channel 22 flows toward the second end 5 of the forming apparatus 1, with the main flow direction being to the right in the axial direction (X direction).

[0036] However, the dimension of the channel 22 in the direction perpendicular to the axis (Y direction) is sufficiently shorter than that in the axial direction (X direction). Therefore, part of the molten glass MG flows along the main flow direction and is separated into a branch flow G s1 ~G s4 The molten glass MG flows toward the outer surface 8a (the lower side in the figure) of the forming apparatus 1 and is discharged from the channel 22. Similarly, a part of the molten glass MG flows into the branch flow G s5 ~G s8 The liquid flows toward the outer surface 8b (upper side in the figure) of the molding device 1 and then flows out of the channel 22.

[0037] On the other hand, the main flow G of the molten glass MG that has advanced along the main flow direction and reached the blocking wall 50 m1 and G m2 When the main flow G collides with the barrier wall 50, its direction is changed by approximately 90 degrees. m1 changes direction by +90° and creates another mainstream G m2 changes direction by -90°.

[0038] Mainstream G of molten glass MG such as barrier 50 m1 and G m2 At a location where a large change occurs in the direction of the blocking wall 50, the molten glass MG is likely to stagnate. In particular, the blocking wall 50 is located at the supply position of the molten glass MG, i.e., the position farthest from the first end 3. Therefore, in the vicinity of the blocking wall 50, the subsequent (fresh) flow of the molten glass MG is unlikely to weaken or eliminate the stagnation of the molten glass MG that has occurred in the vicinity of the blocking wall 50 up to that point.

[0039] As a result, in the vicinity of the second end portion 5, that is, the blocking wall 50, the flow of the molten glass MG becomes difficult to occur, and a stagnant portion 52 occurs.

[0040] Since the molten glass MG has a high temperature, such stagnation portion 52 occurs, and when the molten glass MG stagnates in this stagnation portion 52, specific components in the molten glass MG tend to volatilize. Therefore, in the stagnation portion 52, there is a high possibility that the glass composition will change or devitrification will occur.

[0041] Furthermore, it becomes difficult to make the molten glass MG flow as designed in the stagnation portion 52. As a result, the thickness of the glass ribbon GR on the side corresponding to the second end portion 5 of the forming apparatus 1 is likely to vary in the width direction (X direction in FIG. 1 ).

[0042] It is believed that such influences cause devitrification and compositional changes in the glass ribbon GR, as well as variations in thickness in the width direction of the glass ribbon GR.

[0043] Based on these considerations, the present inventors have found that the above problems can be alleviated by designing a channel structure in which stagnation portions 52 of the molten glass MG are unlikely to occur within the channel, and have arrived at the present invention.

[0044] That is, one embodiment of the present invention is a forming apparatus for forming a glass ribbon by a downdraw method, The glass tube has an axial direction extending from a first end to a second end, the first end being an inlet side for molten glass, the forming device has first and second protrusions on an upper portion thereof extending from the first end to the second end, and a channel through which the molten glass flows from the first end to the second end is formed between the protrusions; A molding device is provided in which, when viewed from above, the channel width in a direction perpendicular to the axial direction of the channel is defined as the channel width, and the channel width near the second end of the channel continuously decreases toward the second end, reaching 0 (zero) at the second end.

[0045] In the forming apparatus according to one embodiment of the present invention, there is no blocking wall 50 on the second end side of the channel as in the conventional forming apparatus 1. Therefore, in the forming apparatus according to one embodiment of the present invention, stagnation portion 52 of molten glass MG is less likely to occur on the second end side of the channel, and problems caused by stagnation portion 52 as described above can be reduced or avoided.

[0046] As a result, in a forming apparatus according to one embodiment of the present invention, devitrification and / or composition changes are less likely to occur when forming a glass ribbon, and thickness variations in the width direction of the glass ribbon can be significantly suppressed.

[0047] (Molding device according to one embodiment of the present invention) Next, a molding apparatus according to one embodiment of the present invention will be described in more detail with reference to FIGS.

[0048] 5 to 7 show a schematic configuration of a molding apparatus 100 according to one embodiment of the present invention (hereinafter referred to as a "first molding apparatus").

[0049] Fig. 5 shows a schematic perspective view of the first molding apparatus 100. Fig. 6 shows a schematic top view of the first molding apparatus 100. Fig. 7 shows a schematic cross section taken along line II-II in Fig. 6.

[0050] 5 to 7, first forming apparatus 100 has an axial direction (X direction) extending from first end 103 to second end 105, and the side of first end 103 is connected to molten glass supply pipe 107. For clarity, the portion behind second end 105 is omitted in FIG. 7.

[0051] 7, the first molding device 100 has a generally wedge-shaped cross section perpendicular to the axial direction, and has a first outer surface 108a and a second outer surface 108b facing each other. The outer surfaces 108a and 108b join at a joining edge 109 at the lower end.

[0052] The first molding device 100 has an upper first portion 111 and a lower second portion 131 .

[0053] The first part 111 of the first molding apparatus 100 has two protrusions 112a and 112b that face each other. The protrusion 112a has an upper surface 113a, an inner surface 114a, and an outer surface 115a. The inner surface 114a and the outer surface 115a each extend along the vertical direction (Z direction) and face each other. The inner surface 114a and the outer surface 115a are connected by the upper surface 113a. Similarly, the protrusion 112b has an upper surface 113b, an inner surface 114b, and an outer surface 115b.

[0054] Protrusion 112a and protrusion 112b may have substantially the same height.

[0055] Furthermore, the first portion 111 of the first molding device 100 has a bottom surface 117 between the two protrusions 112a and 112b. The bottom surface 117 is configured to gradually decrease in depth from the first end 103 to the second end 105 of the first molding device 100.

[0056] Inner surface 114a of protrusion 112a, inner surface 114b of protrusion 112b, and bottom surface 117 define a channel 122 above first portion 111. Due to the shape of bottom surface 117, channel 122 is configured such that its depth gradually decreases from first end 103 toward second end 105 of first molding apparatus 100, reaching zero depth at or near second end 105. Bottom surface 117 may be curved, flat, or a shape that combines a curved and flat surface.

[0057] As shown in FIG. 5, the first part 111 of the first molding device 100 further has a first stopper 170a and a second stopper 170b extending along the vertical direction (Z direction) upstream of the protrusions 112a and 112b in the axial direction.

[0058] The first stopper 170a is provided adjacent to the outer surface 115a of the protrusion 112a on the same side as the outer surface 115a. Similarly, the second stopper 170b is provided adjacent to the outer surface 115b of the protrusion 112b on the same side as the outer surface 115b of the protrusion 112b. The first stopper 170a is configured so that its upper end is higher than the upper surface 113a of the protrusion 112a, and the second stopper 170b is configured so that its upper end is higher than the upper surface 113b of the protrusion 112b.

[0059] The first stopper 170a is provided to regulate the width direction (X direction) dimension of the molten glass MG flowing down along the first outer surface 108a when forming the glass ribbon GR using the first forming apparatus 100. Similarly, the second stopper 170b is provided to regulate the width direction (X direction) dimension of the molten glass MG flowing down along the second outer surface 108b.

[0060] In the first molding device 100, the aforementioned first end 103 can be defined as the boundary position between the first stopper 170a and the protrusion 112a in the axial direction (X direction) when viewed from above, or as the boundary position between the second stopper 170b and the protrusion 112b.

[0061] In contrast to this, in the first molding apparatus 100, the second end 105 can be determined by the installation position of a tip wall 151, which will be described later.

[0062] 5 to 7, the second portion 131 of the first molding apparatus 100 has a first outer surface 133a and a second outer surface 133b that face each other. The first outer surface 133a of the second portion 131 is connected to the outer surface 115a of the first portion 111, thereby forming the first outer side surface 108a of the first molding apparatus 100. Similarly, the second outer surface 133b of the second portion 131 is connected to the outer surface 115b of the first portion 111, thereby forming the second outer side surface 108b of the first molding apparatus 100.

[0063] First forming apparatus 100 further has flow rectifying section 180 between the connection position of supply pipe 107 and first end 103. Flow rectifying section 180 is provided to regulate the flow of molten glass MG supplied from supply pipe 107 to first forming apparatus 100. However, flow rectifying section 180 may be omitted if unnecessary.

[0064] Here, in the first molding apparatus 100, the dimension of the channel 122 perpendicular to the axial direction (X direction) of the first molding apparatus 100 in a top view is referred to as the "channel width." The channel 122 is configured so that the channel width gradually decreases from the first end 103 to the second end 105. In other words, the protrusions 112a and 112b are each configured so that the channel width gradually decreases from the first end 103 to the second end 105. At the second end 105, the channel width is 0 (zero).

[0065] 6, the first portion 111 of the first molding device 100 has a generally "boat-shaped" shape in top view. That is, the channel 122 has a "pointed" shape from the first end 103 to the second end 105.

[0066] Furthermore, the first molding apparatus 100 does not have a blocking wall 50 at the second end 105, as in the conventional molding apparatus 1. Instead, a tip wall 151 is provided at the second end 105.

[0067] It should be noted that leading edge wall 151 is provided to block the flow of molten glass MG that exceeds second end 105. However, it should be noted that the influence of leading edge wall 151 on the flow of molten glass MG is completely different from that of conventional blocking wall 50, as will be described below.

[0068] The characteristic effects of the first molding apparatus 100 will be described below with reference to FIG.

[0069] FIG. 8 schematically shows the general flow of the molten glass MG in the channel 122 when the glass ribbon GR is formed using the first forming apparatus 100.

[0070] As shown in FIG. 8, the molten glass MG supplied from the first end 103 of the first forming device 100 to the channel 122 flows through the main flow H m1 and H m2 As indicated by , the flow direction is to the right in the axial direction (X direction), that is, toward the second end 105 of the first molding device 100.

[0071] However, the dimension of the channel 122 in the channel width direction (Y direction) is sufficiently shorter than that in the axial direction (X direction). Therefore, part of the molten glass MG flows toward the second end 105 and is divided into a branch flow H s1 ~H s4 The molten glass MG flows toward the first outer surface 108a (the lower side in the figure) of the first forming device 100 and is discharged from the channel 122. Similarly, a portion of the molten glass MG flows into the branch flow H s5 ~H s8 The liquid flows toward the second outer surface 108 b (upper side in the figure) of the first molding device 100 and then flows out of the channel 122 .

[0072] Here, in the first forming apparatus 100, the main flow H of the molten glass MG m1 , H m2 Even if the main flow H reaches the second end 105 or its vicinity, the direction of the main flow H is unlikely to be significantly changed there. This is because the channel 122 has a structure in which the channel width of the channel 122 gradually decreases toward the second end 105 and reaches 0 (zero) at the second end 105. Therefore, the main flow H m1 is a tributary H s1 ~H s4 Similarly, the flow of the air flows toward the first outer surface 108a of the first molding device 100, and then flows out of the channel 122 and flows into the main flow H m2 is a tributary H s5 ~H s8 Similarly, the liquid flows toward the second outer surface 108 b of the first molding device 100 and then exits the channel 122 .

[0073] Therefore, in the first molding apparatus 100, stagnation areas 52, which are seen in conventional molding apparatuses 1, are less likely to occur at the second end 105, and the problems of devitrification and / or composition changes in the glass ribbon GR that are seen in conventional molding apparatuses 1 can be significantly suppressed.

[0074] Also, tributary H s1 ~H s8 , mainstream H m1 and H m2 The flow rate can be adjusted by appropriately designing the supply flow rate of the molten glass MG at the first end 103, the depth and gradient of the channel 122, and the channel width dimension of the channel 122 along the axial direction.

[0075] Therefore, tributary H s1 ~H s4 and mainstream H m1 Therefore, by making uniform the amount of molten glass MG flowing down along the first outer surface 108a of the first forming device 100, the thickness of the molten glass MG in the width direction (X direction) on the first outer surface 108a can be made uniform. s5 ~H s8 and mainstream H m2 Therefore, by making uniform the amount of molten glass MG flowing down along second outer surface 108b of first shaping device 100, the thickness of molten glass MG in the width direction on second outer surface 108b can be made uniform.

[0076] Due to the above effects, in the first forming apparatus 100, devitrification and / or composition change is less likely to occur when forming a glass ribbon, and further, it is possible to make the thickness of the glass ribbon uniform in the width direction.

[0077] 5 to 7, in top view, the channel 122 has a configuration in which the channel width gradually decreases from the first end 103 toward the second end 105. In addition, in top view, the first outer surface 108a and the second outer surface 108b each have a shape whose outline is represented by a single curve.

[0078] However, this is merely an example, and the first molding device 100 is not limited to such a form.

[0079] For example, the channel 122 may have a configuration in which, in a top view, the channel width is constant along the axial direction from the first end 103 to a predetermined position (hereinafter referred to as the "inflection position"), and the channel width gradually decreases from the inflection position to the second end 105. For example, when the distance from the first end 103 to the second end 105 is L1, the inflection position may be set in the range of 0.1L1 to 0.9L1 from the first end 103.

[0080] In the present application, the region along the axial direction from the first end 103 at a distance of 0.9L1 to L1, i.e., the range from 0.9L1 to the second end 105, is particularly referred to as the "vicinity" of the second end 105. Using this definition, it can be said that the first molding apparatus 100 has a configuration in which the channel width gradually decreases toward the second end 105 in the "vicinity" of the second end 105, and the channel width at the second end 105 becomes zero.

[0081] In addition, when viewed from above, the first outer surface 108a and the second outer surface 108b may have contours represented by one or more straight lines, or the contours of the first outer surface 108a and the second outer surface 108b may be represented by a combination of curved and straight lines.

[0082] Alternatively, the channel 122 may have a constant depth from the first end 103 to the inflection point, and gradually decrease in depth from the inflection point along the second end 105 .

[0083] In addition, in the first molding apparatus 100, an axis that extends in a direction perpendicular to the channel width of the channel 122 and divides the channel width in half is referred to as a "channel axis." In this case, the outline of the channel 122 near the second end 105 in a top view may be represented by a curve symmetrical with respect to the channel axis and / or one or more straight lines symmetrical with respect to the channel axis.

[0084] Furthermore, in the above description, the operation of first molding device 100 has been described using an example in which protrusions 112a and 112b have substantially the same height. In this case, molten glass MG flows out from both first outer surface 108a and second outer surface 108b.

[0085] However, this is merely an example, and the heights of protrusions 112a and 112b may be different from each other. In this case, the molten glass MG flows out only from the side of one of the protrusions. For example, if the height of protrusion 112a is higher than the height of protrusion 112b, the molten glass MG flowing through channel 122 flows out only from the side of protrusion 112b, and does not flow out from the side of protrusion 112a.

[0086] In addition, various modifications are possible.

[0087] (Another molding device according to one embodiment of the present invention) Next, another molding apparatus according to an embodiment of the present invention will be described with reference to FIGS.

[0088] 9 to 11 show a schematic configuration of another molding apparatus (hereinafter referred to as a "second molding apparatus") 200 according to an embodiment of the present invention.

[0089] Fig. 9 shows a schematic perspective view of the second molding apparatus 200. Fig. 10 shows a schematic top view of the second molding apparatus 200. Fig. 11 shows a schematic cross section taken along line III-III in Fig. 10.

[0090] As shown in Figures 9 to 11, the second molding device 200 has an axial direction (X direction) extending from a first end 203 to a second end 205, and the side of the first end 203 is connected to a molten glass supply pipe 207.

[0091] 11, the second molding device 200 has a generally wedge-shaped cross section perpendicular to the axial direction, and has a first outer surface 208a and a second outer surface 208b facing each other. The first outer surface 208a and the second outer surface 208b join at a joining edge 209 at the lower end.

[0092] The second molding device 200 has an upper first portion 211 and a lower second portion 231 .

[0093] The first portion 211 of the second molding apparatus 200 has two protrusions 212a and 212b that face each other. The protrusion 212a has an upper surface 213a, an inner surface 214a, and an outer surface 215a. The inner surface 214a and the outer surface 215a each extend along the vertical direction (Z direction) and face each other. The inner surface 214a and the outer surface 215a are connected by the upper surface 213a. Similarly, the protrusion 212b has an upper surface 213b, an inner surface 214b, and an outer surface 215b.

[0094] Furthermore, the first portion 211 of the second molding device 200 has a bottom surface 217 between the two protrusions 212a and 212b. The bottom surface 217 is configured to gradually decrease in depth from the first end 203 to the second end 205 of the second molding device 200.

[0095] A channel 222 is defined in the first portion 211 by the inner surface 214a of the protrusion 212a, the inner surface 214b of the protrusion 212b, and the bottom surface 217. The shape of the bottom surface 217 causes the depth of the channel 222 to gradually decrease from the first end 203 toward the second end 205 of the second molding apparatus 200, until the depth becomes zero at or near the second end 205. The bottom surface 217 may have any shape, such as a curved surface, a flat surface, or a shape that combines a curved surface and a flat surface.

[0096] The first portion 211 of the second molding device 200 further has a first stopper 270a and a second stopper 270b extending along the vertical direction (Z direction) on the upstream side of the protrusions 212a and 212b in the axial direction.

[0097] The first stopper 270a is provided adjacent to the outer surface 215a of the protrusion 212a on the same side as the outer surface 215a. Similarly, the second stopper 270b is provided adjacent to the outer surface 215b of the protrusion 212b on the same side as the outer surface 215b of the protrusion 212b. The first stopper 270a is configured to be higher than the upper surface 213a of the protrusion 212a, and the second stopper 270b is configured to be higher than the upper surface 213b of the protrusion 212b.

[0098] The first stopper 270a is provided to regulate the width direction (X direction) dimension of the molten glass MG flowing down along the first outer surface 208a when the glass ribbon GR is formed by the second shaping device 200. Similarly, the second stopper 270b is provided to regulate the width direction (X direction) dimension of the molten glass MG flowing down along the second outer surface 208b.

[0099] In the second molding device 200, the aforementioned first end 203 can be defined as the boundary position between the first stopper 270a and the protrusion 212a in the axial direction (X direction) when viewed from above, or as the boundary position between the second stopper 270b and the protrusion 212b.

[0100] 9 to 11, the second portion 231 of the second molding apparatus 200 has a first outer surface 233a and a second outer surface 233b that face each other. The first outer surface 233a of the second portion 231 is connected to the outer surface 215a of the first portion 211, thereby forming the first outer side surface 208a of the second molding apparatus 200. Similarly, the second outer surface 233b of the second portion 231 is connected to the outer surface 215b of the first portion 211, thereby forming the second outer side surface 208b of the second molding apparatus 200.

[0101] Second forming apparatus 200 further has flow rectifying section 280 between the connection position of supply pipe 207 and first end 203. Flow rectifying section 280 is provided to regulate the flow of molten glass MG supplied from supply pipe 207 to second forming apparatus 200. However, flow rectifying section 280 may be omitted if unnecessary.

[0102] In the second molding apparatus 200, the dimension of the channel 222 perpendicular to the axial direction (X direction) of the second molding apparatus 200 is referred to as the "channel width." Also, the axis extending perpendicular to the channel width of the channel 222 and dividing the channel width into two is referred to as the "channel axis."

[0103] Here, the second molding apparatus 200 further has a direction adjustment member 252 installed in the channel 222. The direction adjustment member 252 has a first wall 260a and a second wall 260b extending vertically (in the Z direction) from the bottom surface 217 of the first portion 211.

[0104] The first wall 260 a and the second wall 260 b have shapes symmetrical with respect to the channel axis of the channel 222 , and are joined to each other at a joining position 262 provided at a predetermined position in the channel 222 .

[0105] In addition, the first wall 260a and the second wall 260b are configured to intersect at one point in a top view at the joining position 262. Therefore, at the joining position 262, the channel width is equal to the sum of the distance from the first wall 260a to the protrusion 212a and the distance from the second wall 260b to the protrusion 212b.

[0106] The joining location 262 is located anywhere on the channel axis between the first end 203 and the second end 205 (but excluding the second end 205).

[0107] For example, in the example shown in Figures 9 and 10, the joining position 262 is set on the channel axis at the boundary between the first stopper 270a and the first outer surface 208a, i.e., at a distance D1 from the first end 203 toward the second end 205.

[0108] First wall 260a is configured such that, in a top view, the distance from first wall 260a to protrusion 212a gradually decreases from joining position 262 to first end point 265a at second end 205. At second end 205, the distance from first wall 260a to protrusion 212a is 0 (zero).

[0109] Similarly, the second wall 260b is configured such that, in a top view, the distance from the second wall 260b to the protrusion 212b gradually decreases from the joining position 262 to a second end point 265b provided at the second end 205. At the second end 205, the distance from the second wall 260b to the protrusion 212b is 0 (zero).

[0110] As a result, the channel 222 is configured by the direction adjustment member 252 so that the channel width gradually decreases from the first end 203 to the second end 205. At the second end 205, the channel width is 0 (zero).

[0111] In addition, in the configuration of the second molding device 200, the channel width downstream of the joining position 262 is defined as the sum of the distance from the first wall 260a to the protrusion 212a and the distance from the second wall 260b to the protrusion 212b.

[0112] In this way, the second molding apparatus 200 has a structure in which the second end 205 does not have the blocking wall 50 as in the conventional molding apparatus 1 .

[0113] The characteristic effects of the second molding apparatus 200 will be described below with reference to FIG.

[0114] FIG. 12 schematically shows the general flow of the molten glass MG in the channel 222 when the glass ribbon GR is formed using the second forming apparatus 200.

[0115] As shown in FIG. 12, the molten glass MG supplied from the first end 203 of the second forming device 200 to the channel 222 flows through the main stream J m1and J. m2 As indicated by , the flow direction is to the right in the channel axis direction (X direction), that is, toward the second end 205 of the second molding device 200.

[0116] However, the dimension of the channel 222 in the channel width direction (Y direction) is sufficiently shorter than that in the channel axis direction (X direction). Therefore, part of the molten glass MG flows toward the second end 205 and is divided into a branch flow J s1 ~J s4 The molten glass MG flows toward the first outer surface 208a (the lower side in the figure) of the second forming device 200 and is discharged from the channel 222. Similarly, a portion of the molten glass MG flows into the branch flow J s5 ~J s8 The liquid flows toward the second outer surface 208b (upper side in the figure) of the second molding device 200 and then flows out of the channel 222.

[0117] Here, in the second forming apparatus 200, the main stream J of the molten glass MG m1 , J m2 Even if the flow reaches the second end 205 or its vicinity, the flow direction is unlikely to be significantly changed there.

[0118] This is because the channel 222 has a structure in which the channel width of the channel 222 gradually decreases from the junction position 262 toward the second end 205 and reaches 0 (zero) at the second end 205. Therefore, the main flow J m1 is a tributary J s1 ~J s4 Similarly, the flow of the liquid flows toward the first outer surface 208a of the second molding device 200, and then flows out of the channel 222 and flows into the main flow J. m2 is a tributary J s5 ~J s8 Similarly, the liquid flows toward the second outer surface 208 b of the second molding device 200 and then exits the channel 222 .

[0119] Therefore, in the second molding device 200, stagnation areas 52 like those in the conventional molding device 1 are less likely to occur at the second end 205, and the problems of devitrification and / or composition changes in the glass ribbon GR that were previously seen can be significantly suppressed.

[0120] Also, tributary J s1 ~J s8 , mainstream J m1 and J. m2 The flow rate can be adjusted by appropriately designing the supply flow rate of the molten glass MG at the first end 203, the depth of the channel 222 and its gradient, the distance D1 from the first end 203 to the joining position 262, and the channel width dimension of the channel 222 along the channel axis direction, etc.

[0121] Therefore, tributary J s1 ~J s4 and mainstream J m1 Therefore, the amount of molten glass MG flowing down along the first outer surface 208a of the second forming device 200 can be made uniform, and thereby the thickness of the molten glass MG in the width direction (X direction) on the first outer surface 208a can be made uniform. s5 ~J s8 and mainstream J m2 This makes it possible to make uniform the amount of molten glass MG flowing down along the second outer surface 208b of the second molding device 200, thereby making it possible to make uniform the widthwise thickness of the molten glass MG on the second outer surface 208b.

[0122] Due to the above effects, in the second shaping device 200, devitrification and / or composition change is less likely to occur when shaping the glass ribbon GR, and it is possible to make the thickness of the glass ribbon GR uniform in the width direction.

[0123] 9 to 11, in top view, the channel 222 has a configuration in which the channel width gradually decreases from the joining position 262 to the second end 205. In top view, the first wall 260a and the second wall 260b each have a shape whose outline is represented by a single curve.

[0124] However, this is merely an example, and the second molding device 200 is not limited to such a form.

[0125] For example, when the distance from the first end 203 to the second end 205 in a top view is L1, the joining position 262 may be set at any position within a range of 0 to 0.9L1 from the first end 203. For example, the joining position 262 may be set within a range of 0 to 0.4L1 from the first end 203, and this range may be within a range of 0.1L1 to 0.3L1, for example.

[0126] Furthermore, in top view, first wall 260a and second wall 260b may have contours represented by one or more straight lines. Alternatively, the contours of first wall 260a and second wall 260b may be represented by a combination of curved and straight lines. Furthermore, forming apparatus 200 may be configured on one side divided into two by a channel axis, and may have only one protrusion through which molten glass MG overflows and flows out.

[0127] In addition, various modifications are possible.

[0128] An embodiment of the present invention has been described above using the first molding apparatus 100 and the second molding apparatus 200 as examples.

[0129] However, the embodiments of the present invention are not limited to the first molding apparatus 100 and the second molding apparatus 200. In other words, the molding apparatus according to the present invention may have any embodiment as long as it has a configuration in which the channel width in the vicinity of the second end continuously decreases toward the second end and reaches zero at the second end.

[0130] This application claims priority based on Japanese Patent Application No. 2020-109936, filed on June 25, 2020, the entire contents of which are incorporated herein by reference. [Explanation of symbols]

[0131] 1. Conventional molding equipment 3 First end 5 Second end 7 Supply pipe 8a, 8b outer surface 9 Confluence 11 First Part 12a, 12b protrusion 13a, 13b top surface 14a, 14b inner surface 15a, 15b external surface 17 Bottom 22 channels 31 Second Part 33a, 33b outer surface 40a first molten glass portion 40b second molten glass portion 50 Baffle 52 Stagnation part 100 First molding device 103 first end 105 second end 107 Supply pipe 108a First outer surface 108b Second outer surface 109 Confluence 111 First Part 112a, 112b protrusion 113a, 113b top surface 114a, 114b inner surface 115a, 115b external surface 117 bottom 122 channels 131 Second Part 133a first outer surface 133b second outer surface 151 Tip wall 170a First stopper 170b Second stopper 180 Rectifier 200 Second molding device 203 First end 205 Second End 207 Supply pipe 208a First outer surface 208b Second outer surface 209 Confluence 211 First Part 212a, 212b protrusion 213a, 213b top surface 214a, 214b inner surface 215a, 215b external surface 217 bottom 222 channels 231 Second Part 233a first outer surface 233b Second outer surface 252 Direction adjustment member 260a First Wall 260b Second Wall 262 Joint position 265a First End 265b Second End 270a First stopper 270b Second stopper 280 Rectifier GR Glass Ribbon MG molten glass

Claims

1. A forming apparatus for forming a glass ribbon, The glass tube has an axial direction extending from a first end to a second end, the first end being an inlet side for molten glass, the forming device has first and second protrusions on an upper portion thereof extending from the first end to the second end, and a channel through which the molten glass flows from the first end to the second end is formed between the protrusions; A molding device, wherein, when viewed from above, the channel width is defined as a direction perpendicular to the axial direction of the channel, and the channel width near the second end of the channel continuously decreases toward the second end and reaches 0 (zero) at the second end.

2. The molding device according to claim 1 , wherein, in a top view, the channel has a shape near the second end that is tapered toward the second end.

3. The molding apparatus according to claim 1 or 2, wherein the heights of the first protrusion and the second protrusion are substantially equal.

4. The molding apparatus according to claim 1 or 2, wherein the first protrusion is higher than the second protrusion.

5. The channel has a channel axis that divides the channel width in half along the axial direction in a top view, The molding apparatus of claim 2 , wherein the pointed shape has a symmetrical curve about the channel axis.

6. The channel has a channel axis that divides the channel width in half along the axial direction in a top view, 6. The forming apparatus of claim 2 or 5, wherein the pointed shape has one or more straight lines symmetrical about the channel axis.

7. When viewed from above, a direction adjustment member is installed in the channel, the direction adjustment member has a first wall and a second wall extending vertically from a bottom surface of the channel; the channel has a channel axis extending in a direction perpendicular to the channel width and dividing the channel width in half; the first wall and the second wall have shapes symmetrical with respect to the channel axis and are joined to each other at a joint position provided at a predetermined position on the channel axis; the joining position is provided at any position between the first end and the second end (but excluding the second end); On the second end side of the joining position, the channel width is represented by the sum of the distance from the first wall to the first protrusion and the distance from the second wall to the second protrusion; 2. The molding apparatus of claim 1, wherein in the bonded position, the channel width is equal to the sum of the distance from the first wall to the first protrusion and the distance from the second wall to the second protrusion.

8. The molding apparatus of claim 7 , wherein, in a top view, the first wall and the second wall have a curve.

9. The molding apparatus according to claim 7 or 8, wherein, in a top view, the first wall and the second wall have one or more straight lines.

10. 10. The molding apparatus according to claim 7, wherein, in a top view, the first wall and the second wall have a shape in which the channel width continuously decreases from the joining position to the second end.

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