Glass article manufacturing apparatus and manufacturing method thereof

Abstract

To suppress variation in thickness of a glass ribbon in a width direction even when forming a glass ribbon from a low-viscous glass.SOLUTION: A device for manufacturing a glass article includes a molding device 1 for molding a glass ribbon R from a molten glass M. The molding device 1 includes: a molding 2 including a pair of side surfaces 5 for causing molten glasses M to flow down therethrough and a lower end part 6 for merging molten glasses M flowing down the pair of side surfaces 5; and a slot-like flow channel 3 for supplying molten glasses M respectively to the pair of side surfaces 5 of the molding 2.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to improvements in techniques for producing glass articles by the fusion process. [Background technology]

[0002] The fusion method (overflow downdraw method) is sometimes used as a method for manufacturing glass articles such as glass plates. In this method, a forming apparatus is equipped with a roughly wedge-shaped forming body. Molten glass supplied to the forming body overflows from grooves (overflow grooves) formed at the top of the forming body, then flows down both side surfaces of the forming body and joins at the bottom end. In this way, a belt-shaped glass ribbon is continuously formed from the molten glass (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-214349 [Non-patent literature]

[0004] [Non-Patent Document 1] Kamei Saburo, "Theory and Calculation of Chemical Machinery (2nd Edition)", Sangyo Tosho, pp.36-37 Summary of the Invention [Problem to be solved by the invention]

[0005] Some glass articles are required to be molded using glass having a low liquidus viscosity, for example, for the purpose of achieving a high refractive index.

[0006] However, when a glass ribbon is formed from such low-viscosity molten glass using the fusion method, the thickness (height) of the molten glass overflowing from the grooves at the top of the forming body tends to be small due to the low viscosity. In other words, the molten glass is less likely to overflow evenly from the grooves at the top of the forming body. As a result, the flow rate of the molten glass flowing down the side of the forming body becomes unstable, leading to a problem that the thickness of the glass ribbon tends to vary across the width.

[0007] An object of the present invention is to suppress thickness variations in the width direction of a glass ribbon even when the glass ribbon is formed from low-viscosity molten glass. [Means for solving the problem]

[0008] (1) The present invention, which was invented to solve the above problems, is a glass article manufacturing apparatus including a molding device that forms a glass ribbon from molten glass, characterized in that the molding device includes a molding body having a pair of sides through which molten glass flows and a lower end where the molten glass flowing down each side meets, and a slot-shaped flow path that supplies molten glass to the sides of the molding body.

[0009] In this way, the molten glass is supplied to the side surface of the forming body through the slot-shaped flow path. Because the flow path cross section of the slot-shaped flow path is narrowed to a slot shape (long hole shape or rectangular shape), resistance is applied to the flow of the molten glass as it passes through the slot-shaped flow path. In other words, the flow rate of the molten glass can be adjusted in the slot-shaped flow path. Therefore, even if the molten glass has a low viscosity, the flow rate of the molten glass supplied to the side surface of the forming body is stable. Therefore, thickness variations in the width direction of the glass ribbon can be suppressed.

[0010] (2) In the above configuration (1), the forming device preferably includes a reservoir above the forming body for storing the molten glass supplied to the slot-shaped flow path.

[0011] In this way, the molten glass stored in the storage section is supplied to the entire slot-shaped flow path at uniform pressure, thereby further equalizing the flow rate of molten glass supplied to the side of the forming body and further suppressing thickness variations in the width direction of the glass ribbon.

[0012] (3) In the above configuration (2), the reservoir preferably has an open top.

[0013] If the top of the reservoir is closed, a pressure gradient occurs within the reservoir. Therefore, unless the shape of the slot-shaped flow path is made complex in consideration of the pressure gradient, the flow rate of molten glass supplied to the side of the forming body may vary in the width direction. Therefore, it is preferable that the top of the reservoir is open as described above. This makes it difficult for a pressure gradient to occur within the reservoir, so that the flow rate of molten glass supplied to the side of the forming body becomes uniform in the width direction even without making the slot-shaped flow path complex in shape.

[0014] (4) In the configuration of (2) or (3) above, it is preferable that the side of the molded body has a vertical surface and an inverted slope connected to the lower end of the vertical surface, the molding device has a wall member extending in the up-and-down direction along the vertical surface, the lower part of the wall member faces the vertical surface via a gap, the slot-shaped flow path is composed of a member including the vertical surface and the lower part of the wall member, and the storage section is composed of a member including the upper part of the wall member.

[0015] In this manner, the slot-shaped flow path is disposed along the vertical surface of the forming body. Here, when the slot-shaped flow path is disposed along the inverted slope of the forming body, gravity acts on the inverted slope in a direction that separates the molten glass, while gravity acts on the slope (wall surface) of the slot-shaped flow path facing the inverted slope in a direction that brings the molten glass into close contact with the slope. In other words, the molten glass is more likely to separate from the inverted slope of the forming body and flow down along the slope of the slot-shaped flow path facing the inverted slope. As a result, air is more likely to be entrained between the forming body and the molten glass. Furthermore, air adhering to the side surface of the forming body is less likely to escape, and an air layer is more likely to form. As a result, the air layer may cause a change in the flow rate of the molten glass and an instability in the flow, resulting in a change in the thickness of the glass ribbon. Furthermore, air may be mixed into the formed glass ribbon, resulting in the formation of bubbles. Therefore, it is preferable to dispose the slot-shaped flow path along the vertical surface of the forming body as described above. This allows the molten glass to flow smoothly down along the vertical surface, thereby preventing air from being entrained between the forming body and the molten glass.

[0016] Furthermore, according to the above configuration, since the reservoir is formed of a member including the upper part of the wall member, the volume of the reservoir can be reduced, and stagnation of the molten glass can be suppressed. This makes it difficult for heterogeneous glass due to stagnation to form in the reservoir, and makes it possible to form a high-quality glass article (e.g., a glass plate).

[0017] (5) In any of the configurations (1) to (4) above, it is preferable that the side surface of the molded body has a vertical surface and an inverted slope connected to the lower end of the vertical portion, and the slot-shaped flow path is arranged along the vertical surface.

[0018] In this way, for the same reason as above, the molten glass flows smoothly down along the vertical surface, and it is possible to prevent air from being entrained between the forming body and the molten glass.

[0019] (6) In any of the above configurations (1) to (5), when the size of the gap of the slot-shaped flow path is G [cm], it is preferable that G satisfies the relationship G≦t where t is in the following formula:

number

[0020] Here, t is an estimated value for the thickness of the molten glass flowing down the side of the forming body (see Non-Patent Document 1). Therefore, if G≦t is set as in the above configuration, the entire slot-shaped flow path is reliably filled with molten glass. As a result, the amount of molten glass supplied to the side of the forming body is stabilized, and the situation in which air is entrapped between the forming body and the molten glass can be suppressed.

[0021] (7) In any of the above configurations (1) to (6), the forming device preferably includes guide members for guiding both widthwise ends of the molten glass flowing down the side surfaces of the forming body.

[0022] In this way, both widthwise ends of the molten glass are guided while being restricted by the guide members, so that the widthwise dimension of the molten glass flowing down the side surface of the forming body can be made constant, and as a result, the widthwise dimension of the formed glass ribbon is stabilized.

[0023] (8) The present invention, which was invented to solve the above problems, is a method for manufacturing a glass article, which includes a forming step of forming a glass ribbon from molten glass, and is characterized in that in the forming step, molten glass is supplied to a pair of side surfaces of a forming body through a slot-shaped flow path, and the molten glass flowing down each side surface is made to merge at the lower end of the forming body, thereby forming a glass ribbon.

[0024] In this way, the same effects as those of the corresponding configurations already described can be obtained. [Effects of the Invention]

[0025] According to the present invention, even when a glass ribbon is formed from low-viscosity molten glass, thickness variations in the width direction of the glass ribbon can be suppressed. [Brief explanation of the drawings]

[0026] [Figure 1] FIG. 2 is a perspective view showing a forming device included in the glass article manufacturing apparatus according to the first embodiment of the present invention. [Figure 2] 2 is a cross-sectional view of the molding device shown in FIG. 1 along the line AA. [Figure 3] 2 is a cross-sectional view of the molding device shown in FIG. 1 . [Figure 4] FIG. 2 is a cross-sectional view taken along the line AA of the cross-sectional view of the molding device in FIG. 1, showing the state in which the molding step is being carried out. [Figure 5] FIG. 4 is a perspective view showing a forming device included in a glass article manufacturing apparatus according to a second embodiment of the present invention. [Figure 6] 6 is a CC cross-sectional view of the molding device shown in FIG. 5. [Figure 7] FIG. 6 is a DD cross-sectional view of the molding device shown in FIG. 5. [Figure 8] 6 is a cross-sectional view taken along line CC of the molding device shown in FIG. 5, showing how a molding step is being carried out. FIG. [Figure 9] 10 is a graph showing the results of a numerical analysis of a molding device according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0027] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the illustrated Cartesian coordinate system consisting of X, Y, and Z, the X and Y directions are horizontal directions, and the Z direction is vertical. Of the horizontal directions, the X direction is referred to as the width direction. Furthermore, by assigning the same reference numerals to corresponding components in each embodiment, redundant description may be omitted. When only a portion of a configuration is described in each embodiment, the configurations of other previously described embodiments may be applied to the remaining portions of the configuration. Furthermore, in addition to the combinations of configurations explicitly stated in the description of each embodiment, configurations of multiple embodiments may be partially combined together even if not explicitly stated, as long as there is no particular problem with the combination.

[0028] (First embodiment) As shown in FIGS. 1 to 4, the apparatus for manufacturing a glass article according to the first embodiment includes a forming device 1 that forms a band-shaped glass ribbon R from molten glass M.

[0029] The molding device 1 includes a molded body 2 , a slot-shaped flow path 3 , and a storage section 4 .

[0030] The formed body 2 is formed of a long refractory material extending along the width direction X. The formed body 2 is a member having a generally wedge-shaped cross section, which has a pair of side surfaces 5 along which the molten glass M flows and a lower end portion 6 where the molten glass M flowing down each side surface 5 joins. In this embodiment, the side surfaces 5 have a vertical surface 5a and an inverted slope 5b connected to the lower end of the vertical surface 5a. The portion where the lower ends of the inverted slopes 5b of each side surface 5 intersect with each other defines the lower end portion 6 of the formed body 2.

[0031] In this embodiment, a groove 7 extending along the width direction X is formed at the top of the formed body 2. In other words, a formed body designed for performing the fusion method can be used as the formed body 2 as is. The depth of the groove 7 may be constant, or may gradually become shallower from one end side in the width direction X to the other end side. Molten glass M is supplied into the groove 7 through a supply pipe 8 provided at one end side of the groove 7 in the width direction X. The method of supplying the molten glass M is not limited to this. For example, the molten glass M may be supplied from both ends of the groove 7 in the width direction X, or the molten glass M may be supplied from above the groove 7. A thermal spray coating (e.g., a platinum thermal spray coating) may be provided on the portion of the formed body 2 that comes into contact with the molten glass.

[0032] The slot-shaped flow passage 3 is provided on each side surface 5 of the forming body 2 so as to supply the molten glass M to each side surface 5. In this embodiment, the slot-shaped flow passage 3 is arranged along the vertical surface 5a of the forming body 2. In other words, the slot-shaped flow passage 3 is not arranged on the reverse slope surface 5b of the forming body 2.

[0033] The slot-shaped flow path 3 has a long slot shape (long hole shape or rectangular shape) along the width direction X, and the cross-sectional shape of the flow path is constant at any position in the vertical direction Z (see FIGS. 2 and 3). An inlet 3a is provided at the upper end of the slot-shaped flow path 3 for allowing the molten glass M to flow into the slot-shaped flow path 3. An outlet 3b is provided at the lower end of the slot-shaped flow path 3 for allowing the molten glass M to flow out of the slot-shaped flow path 3. To make the drawings easier to understand, the inlet 3a and the outlet 3b are cross-hatched in FIG. 1 (the same applies to FIG. 5 described below).

[0034] In this embodiment, the inlet 3a is provided at the upper end of the vertical surface 5a of the molded body 2, and the outlet 3b is provided between the upper and lower ends of the vertical surface 5a of the molded body 2. By providing the inlet 3a at the same height as the upper end of the vertical surface 5a of the molded body 2 in this way, the molten glass M can easily flow into the slot-shaped channel 3. On the other hand, by providing the outlet 3b between the upper and lower ends of the vertical surface 5a of the molded body 2, the flow of the molten glass M flowing down the side surface 5 of the molded body 2 becomes stable. Also, the time during which the outer surface of the molten glass M (the surface opposite to the surface contacting the molded body 2) contacts other members is shortened, and the surface properties of the glass ribbon R become good. In particular, from the viewpoint of maintaining the good surface properties of the glass ribbon R, it is important that the outer surface of the molten glass M does not contact other members on the reverse inclined surface 5a.

[0035] In addition, in this embodiment, as shown in FIG. 4, the distance L1 that the molten glass M flows down along the vertical surface 5a after exiting the outlet 3b is set to be shorter than the distance L2 that the molten glass M flows down along the reverse inclined surface 5b. The molten glass M flowing down the side surface 5 of the molded body 2 has the fastest flow velocity and tends to have a thinner thickness when the flow direction is vertically downward. Therefore, when the molten glass M has a low viscosity, if the distance L1 that the molten glass M flows down along the vertical surface 5a after exiting the outlet 3b becomes long, the flow of the molten glass M may become unstable and turbulence may occur. Therefore, it is desirable that L1 < L2.

[0036] The storage portion 4 is a tank for storing the molten glass M supplied to the slot-shaped channel 3, and is provided directly above the molded body 2. The upper part of the storage portion 4 is open to suppress the generation of a pressure gradient inside the storage portion 4. That is, an opening 4a is formed in the upper part of the storage portion 4. Thereby, a uniform pressure is applied to the entire inlet 3a of the slot-shaped channel 3.

[0037] The forming apparatus 1 includes a cover member 9 that surrounds the formed body 2 to form the slot-shaped flow path 3 and the reservoir 4. The cover member 9 may be made of, for example, a refractory material, platinum, or a platinum alloy, or a combination thereof. When made of a refractory material, a thermally sprayed coating (e.g., a platinum thermally sprayed coating) may be provided on the portion that comes into contact with the molten glass. The cover member 9 includes a wall member 10 that extends vertically along the vertical surface 5a of the formed body 2. The lower portion 10b of the wall member 10 faces the vertical surface 5a via a gap, and the upper portion 10a of the wall member 10 extends above the formed body 2 while remaining aligned with the vertical surface 5a. In other words, the slot-shaped flow path 3 is made of a member that includes the vertical surface 5a and the lower portion 10b of the wall member 10, and the reservoir 4 is made of a member that includes the upper portion 10a of the wall member 10.

[0038] When the size of the gap of the slot-shaped flow path 3 is G [cm], it is preferable that G satisfies the relationship G≦t where t is in the following formula: In this embodiment, the size of the gap of the slot-shaped flow path 3 is constant in the width direction X and the vertical direction Z.

number

[0039] In this embodiment, the slot-like flow path 3 is provided on the vertical surface 5a of the molded body 2, and therefore θ in the formula is 0° (that is, cos θ=1).

[0040] The cover member 9 further includes a pair of plate-like guide members 11 that guide both widthwise ends of the molten glass M that flows down the side surface 5 of the forming body 2 (specifically, near the lower end of the vertical surface 5a and the reverse slope 5b) after flowing out of the outlet 3b of the slot-shaped flow path 3. The outlet 3b of the slot-shaped flow path 3 supplies the molten glass M between the pair of guide members 11. This makes the widthwise dimension of the molten glass M flowing down the side surface 5 of the forming body 2 constant, thereby stabilizing the widthwise dimension of the formed glass ribbon R.

[0041] Next, a method for manufacturing a glass article using the manufacturing apparatus configured as above will be described, taking as an example a case where the glass article is a glass plate.

[0042] The method for manufacturing a glass article according to this embodiment includes a forming step (see FIG. 4 ) of forming a glass ribbon R from molten glass M using a forming apparatus 1, an annealing step of annealing the glass ribbon R, a cooling step (not shown) of cooling the glass ribbon R, a first cutting step (not shown) of cutting the glass ribbon R in the width direction X at predetermined lengths to obtain glass sheets, and a second cutting step (not shown) of cutting and removing edge portions at both ends in the width direction of the glass sheet. Note that the following description will mainly focus on the forming step.

[0043] As shown in FIG. 4 , in the forming step, first, molten glass M is supplied to the reservoir 4 through the supply pipe 8. Since the top of the reservoir 4 is open, the liquid level of the molten glass M in the reservoir 4 is horizontal. In this embodiment, the molten glass M is supplied through the supply pipe 8 into the interior of a groove 7 that constitutes a part of the reservoir 4. Therefore, it is expected that the molten glass M is extruded from the bottom side of the reservoir 4, and an effect of suppressing the formation of a glass stagnation layer in the reservoir 4 can be expected. Here, the glass stagnation layer can cause the generation of heterogeneous glass, and may also lead to a deterioration in the quality of the glass ribbon R. Therefore, it is preferable to suppress the formation of a glass stagnation layer in the reservoir 4.

[0044] The molten glass M stored in the reservoir 4 is supplied to the side surface 5 of the forming body 2 through the slot-shaped flow path 3. The molten glass M supplied to the side surface 5 of the forming body 2 through the slot-shaped flow path 3 flows down along the vertical surface 5a and the inverted slope 5b of the forming body 2 while being restricted in its spread in the width direction X by the guide member 11. Then, at the lower end 6 of the forming body 2, the molten glass M flowing down each side surface 5 of the forming body 2 joins together, forming a band-shaped glass ribbon R. Below the forming body 2, both widthwise end portions of the glass ribbon R are clamped by edge rollers (cooling rollers) 12 to suppress shrinkage of the glass ribbon R in the width direction X. As a result, edge portions that are relatively thicker at both widthwise end portions of the glass ribbon R than at the widthwise central portion are formed. The glass ribbon R then undergoes an annealing process, a cooling process, a first cutting process, and a second cutting process, thereby producing a glass sheet from which the edge portions have been removed.

[0045] In this manufacturing method, the cross section of the slot-shaped flow path 3 is narrowed into a slot shape, so that resistance is applied to the flow of the molten glass M when passing through the slot-shaped flow path 3. In other words, the flow rate of the molten glass M can be adjusted in the slot-shaped flow path 3. Therefore, even if the molten glass M has a low viscosity, the flow rate of the molten glass M supplied to the side surface 5 of the forming body 2 becomes uniform in the width direction X. Therefore, the thickness variation of the glass ribbon R in the width direction X can be suppressed. In other words, the thickness variation of the glass sheet obtained from the glass ribbon R is also reduced.

[0046] Furthermore, because the slot-like flow paths 3 are arranged along the vertical surface 5a of the forming body 2, the molten glass M flows smoothly down along the vertical surface 5a, preventing air from being entrained between the forming body 2 and the molten glass M. As a result, an air layer is less likely to form on the side surface 5 of the forming body 2. This prevents the thickness of the glass ribbon R from changing due to the air layer. Furthermore, the generation of air bubbles in the glass ribbon R can also be suppressed.

[0047] Here, the molten glass M preferably contains, in mass %, 10 to 31% of TiO2 + Nb2O5, 4 to 15% of B2O3, 3 to 20% of SiO2, 40 to 65% of Ln2O3 (Ln is at least one selected from La, Gd, Y, and Yb), and 0 to 10% of ZrO2. Molten glass M having such a glass composition can be used to produce a glass plate having a high refractive index (for example, a refractive index of 1.65 or more) and excellent chemical durability.

[0048] The viscosity of the molten glass M at the molding temperature is 10 1 poise or less, 10 0.9 Poise and below, especially 10 0.8 The present invention is particularly effective for molten glass M having such a low viscosity.

[0049] A glass plate obtained from the glass ribbon R is suitable, for example, as a light guide plate. Examples of the light guide plate include light guide plates used in wearable image display devices selected from projector-equipped glasses, eyeglass-type or goggle-type displays, virtual reality (VR) or augmented reality (AR) display devices, and virtual image display devices.

[0050] Second Embodiment 5 to 8, the glass article manufacturing apparatus and manufacturing method according to the second embodiment differ from the first embodiment in the shape of the formed body 2 and the method of supplying the molten glass M to the reservoir 4. The following description will focus on these differences.

[0051] Similar to the first embodiment, the molded body 2 is a member having a generally wedge-shaped cross section, and a pair of side surfaces 5 have a vertical surface 5a and an inverted slope 5b. However, unlike the first embodiment, no groove is formed in the top of the molded body 2. In other words, the top of the molded body 2 is a flat surface extending horizontally.

[0052] Unlike the first embodiment, the supply pipe 8 is positioned at a position corresponding to the opening 4a at the top of the storage section 4, and the molten glass M is supplied from the supply pipe 8 into the storage section 4 through the opening 4a at the top of the storage section 4.

[0053] As in the first embodiment, the slot-like flow paths 3 are arranged along the vertical surfaces 5a of the respective side surfaces 5 of the forming body 2 so as to supply the molten glass M to the respective side surfaces 5.

[0054] Even with this configuration, the molten glass M can be supplied to the side surface 5 of the forming body 2 through the slot-shaped flow path 3, so that variations in thickness of the glass ribbon R in the width direction X can be suppressed.

[0055] The present invention is not limited to the configuration of the above-described embodiment, nor is it limited to the above-described effects. The present invention can be modified in various ways without departing from the spirit of the present invention.

[0056] In the above embodiment, the slot-shaped flow path 3 is disposed along the vertical surface 5a of the forming body 2. However, the position of the slot-shaped flow path 3 is not particularly limited as long as the molten glass M can be supplied to the side surface 5 of the forming body 2. The slot-shaped flow path 3 may include a first flow path disposed along the vertical surface 5a of the forming body 2, and a second flow path that communicates with the lower end of the first flow path and is disposed along the reverse slope 5b of the forming body 2. However, if the slot-shaped flow path 3 is disposed along the reverse slope 5b, there is a risk of air being entrapped between the forming body 2 and the molten glass M. Therefore, it is preferable to dispose the slot-shaped flow path 3 so as to extend only along the vertical surface 5a of the forming body 2.

[0057] In the above embodiment, the side surface 5 of the molded body 2 has the vertical surface 5a, but the shape of the vertical surface 5a may be changed to an inclined surface or a curved surface, or may be omitted. However, from the viewpoint of suppressing variations in thickness of the glass ribbon R in the width direction X, it is preferable that the side surface 5 of the molded body 2 has the vertical surface 5a.

[0058] In the above embodiment, the case where the top of the storage section 4 is open has been described, but the top of the storage section 4 may also be closed. However, if the top of the storage section 4 is closed, a pressure gradient will occur within the storage section 4, and the shape of the slot-shaped flow channel 3 needs to be changed in accordance with the pressure gradient. For example, in a high-pressure region, the gap of the slot-shaped flow channel 3 is made relatively large, and in a low-pressure region, the gap of the slot-shaped flow channel 3 is made relatively small. When the shape of the slot-shaped flow channel 3 is changed in accordance with the pressure gradient in this way, the shape of the slot-shaped flow channel 3 tends to become complex. Therefore, from the perspective of simplifying the shape of the slot-shaped flow channel 3, it is preferable to open the top of the storage section 4.

[0059] In the above embodiment, the glass article is a glass plate. However, the glass article may be, for example, a glass roll formed by winding a glass ribbon around a core or the like. [Example]

[0060] The effects of using the forming apparatus according to the second embodiment shown in Figures 5 to 8 were confirmed by numerical analysis. In the numerical analysis, the liquid level of the molten glass in the reservoir and the widthwise distribution of the flow rate of the molten glass at the outlet of the slot flow path provided along the vertical surface of the forming body were confirmed. The conditions for the numerical analysis were as follows: (1) Slotted flow path Slot flow path width: 45cm Gap size of slot flow path G: 0.023 cm Slot flow channel length (vertical length): 0.5 cm (2) Molten glass Viscosity of molten glass supplied to the reservoir: 10 0.84 poise Flow rate of molten glass supplied to the reservoir: 0.28 cm 3 / s Density of molten glass supplied to the reservoir: 5 g / cm 3

[0061] The results of the above numerical analysis are shown in Figure 9. In this figure, the flow rate of molten glass is expressed as a percentage [%] of the flow rate in each section divided in the width direction to the total flow rate. From these results, it can be confirmed that the liquid level of the molten glass in the reservoir is almost horizontal, and that the flow rate of molten glass flowing down the side of the forming body is uniform in the width direction. [Explanation of symbols]

[0062] 1 Molding equipment 2. Molded body 3 Slotted flow channel 3a Inlet 3b Outlet 4. Storage section 5 Sides 5a vertical plane 5b Reverse Slope 6 Lower end 7 grooves 8 Supply pipe 9 Cover member 10 Wall components 11 Guide member R Glass Ribbon M Molten Glass

Claims

1. An apparatus for manufacturing a glass article, comprising a forming device for forming a glass ribbon from molten glass, The molding device a forming body having a pair of side surfaces along which the molten glass flows and a lower end portion along which the molten glass flows down from the side surfaces and joins the molten glass; a slot-shaped flow channel for supplying the molten glass to the side surface of the forming body; a reservoir located above the forming body and configured to store the molten glass supplied to the slot-shaped flow path, The glass article manufacturing apparatus is characterized in that the storage section has an open top.

2. The side surface of the molded body includes a vertical surface and an inverted slope connected to a lower end of the vertical surface, the molding device includes a wall member extending in a vertical direction along the vertical plane, a lower portion of the wall member facing the vertical surface with a gap therebetween; the slot-shaped flow path is formed by a member including a lower portion of the wall member and the vertical surface, The glass article manufacturing apparatus according to claim 1 , wherein the storage section is formed of a member including an upper portion of the wall member.

3. The side surface of the molded body includes a vertical surface and an inverted slope connected to a lower end of the vertical surface, 3. The apparatus for manufacturing a glass article according to claim 1, wherein the slot-shaped flow path is arranged along the vertical plane.

4. The glass article manufacturing apparatus according to any one of claims 1 to 3, wherein the size of the gap of the slot-shaped flow path is G [cm], and G satisfies the relationship G≦t where t is the following formula: [Equation 1] t: thickness of molten glass [cm] ρ: density of molten glass [g / cm 3 ] g: acceleration due to gravity [cm / s 2 ] θ: Angle [°] between the vertical direction of the side surface of the molded body and the position where the slot-shaped flow path is arranged μ: viscosity of molten glass [poise] V: flow rate of molten glass [cm 3 / s]

5. The glass article manufacturing apparatus according to any one of claims 1 to 4, wherein the forming device is provided with guide members that guide both widthwise ends of the molten glass flowing down the side surfaces of the forming body.

6. A method for manufacturing a glass article, comprising a forming step of forming a glass ribbon from molten glass, In the forming step, the molten glass is supplied to a pair of side surfaces of a forming body through a slot-shaped flow path, and the molten glass flowing down each of the side surfaces is joined at a lower end of the forming body to form the glass ribbon; and a reservoir for storing the molten glass supplied to the slot-shaped flow path is provided above the forming body; A method for manufacturing a glass article, wherein the storage section has an open top.

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