Glass ribbon manufacturing apparatus

Abstract

A glass ribbon manufacturing apparatus according to the present invention comprises: a conditioning tank for accommodating molten glass; a nozzle coupled to the lower end of the conditioning tank and comprising an opening for discharging the molten glass; and a barrier disposed around the opening.

Description

Glass ribbon manufacturing device

[0001] The present invention relates to a glass ribbon manufacturing device, and more specifically, to a downdraw type glass ribbon manufacturing device.

[0002] When manufacturing glass ribbons, devitrification may occur if the glass melt is maintained at a temperature lower than the liquid phase temperature for a certain period of time. To prevent such devitrification, a method using a composition that reduces the viscosity of the glass melt has been proposed. However, to prevent defects such as warping or streaking in the glass ribbon, the distribution, homogenization, and temperature of the glass melt must be finely and complexly adjusted. In the process of adjusting the temperature to improve the drawing volume or thickness quality, conditions favorable for devitrification may be formed, making it difficult to avoid devitrification in the glass ribbon. Therefore, technology for effectively managing devitrification is still required.

[0003] The objective of the present invention is to provide a glass ribbon manufacturing device capable of effectively managing devitrification.

[0004] A glass ribbon manufacturing apparatus according to the present invention comprises: a conditioning tank for receiving a glass melt; a nozzle coupled to the bottom of the conditioning tank and having an opening for discharging the glass melt; and a barrier disposed around the opening.

[0005] In addition, the opening includes a short side and a long side, and the barrier may be positioned adjacent to the long side of the opening.

[0006] In addition, the barrier may be positioned at a predetermined distance from the long side of the opening.

[0007] In addition, the barrier may be oriented parallel to the long side of the opening.

[0008] In addition, the barrier may be formed as a pair and positioned facing each other with the opening in between.

[0009] In addition, the barrier may be formed with a length shorter than the long side of the opening.

[0010] In addition, the barrier may be positioned in the center with respect to the long side of the opening.

[0011] In addition, both ends of the barrier may be spaced apart from the side walls of the conditioning tank.

[0012] In addition, the height of the barrier may be 7% to 10% of the height of the side wall of the conditioning tank.

[0013] In addition, the width of the barrier is 90% to 95% of the width of the opening, where the width may be the length in a direction parallel to the long side of the opening.

[0014] In addition, the distance between the nozzle and the barrier may be 80% to 90% of the distance between the nozzle and the side wall of the conditioning tank.

[0015] In addition, the thickness of the barrier may be thicker than the thickness of the side wall of the conditioning tank.

[0016] In addition, at least one of the conditioning tank, the nozzle, and the barrier may be formed of a platinum-rhodium alloy.

[0017] The glass ribbon manufacturing apparatus according to the present invention can induce devitrification to form at both ends in the width direction of the glass ribbon by controlling the flow of the glass melt using a barrier. Therefore, by removing both ends in the width direction of the glass ribbon in a subsequent process, a glass ribbon without devitrification can be easily obtained.

[0018] FIG. 1 is a front schematic diagram of a glass ribbon manufacturing apparatus according to an embodiment of the present invention.

[0019] Figure 2 is a schematic cross-sectional view taken along line II-II in Figure 1.

[0020] Figure 3 is a planar schematic view of the nozzle and barrier as seen from inside the conditioning tank.

[0021] Figure 4 shows the flow of melted glass being discharged from inside the conditioning tank to the opening of the nozzle.

[0022] FIG. 5 is a perspective schematic diagram of a glass ribbon manufactured by a glass ribbon manufacturing device according to an embodiment of the present invention.

[0023] A glass ribbon manufacturing device (10) according to an embodiment of the present invention will be described in detail with reference to the drawings.

[0024] FIG. 1 is a front schematic diagram of a glass ribbon manufacturing apparatus (10) according to an embodiment of the present invention. FIG. 2 is a cross-sectional schematic diagram cut along line II-II in FIG. 1. FIG. 3 is a planar schematic diagram viewed from inside the conditioning tank (12) toward the nozzle (13) and barrier (14). FIG. 4 shows the flow of glass melt being discharged from inside the conditioning tank (12) toward the opening (13a) of the nozzle (13).

[0025] Referring to FIGS. 1 to 4, a glass ribbon manufacturing apparatus (10) according to an embodiment of the present invention includes a supply tube (11), a conditioning tank (12), a nozzle (13), and a barrier (14).

[0026] The supply tube (11) serves to supply a glass melt to the conditioning tank (12) for manufacturing a glass ribbon. The glass melt may be, for example, a silicate glass melt.

[0027] The conditioning tank (12) serves to adjust the glass melt to a temperature suitable for forming glass ribbons.

[0028] A supply tube (11) can be connected to the top of the conditioning tank (12). Additionally, the bottom of the conditioning tank (12) is open so that a nozzle (13) can be connected to the bottom.

[0029] In FIG. 2, the side wall of the conditioning tank (12) is exemplified as being formed to slope inward as it goes downward, but the present invention is not limited thereto.

[0030] The nozzle (13) is connected to the bottom of the conditioning tank (12) via a seal (not shown), so that the nozzle (13) can form the entire bottom surface of the conditioning tank (12).

[0031] The nozzle (13) has an opening (13a) for discharging the melted glass and forming it into a glass ribbon.

[0032] The opening (13a) may be formed in an elongated shape corresponding to the cross-section of the glass ribbon. Although the opening (13a) is illustrated in FIGS. 3, 4, etc. as being formed in a rectangular shape, it is not necessarily limited to this shape, and it is possible to form it in a rectangular shape, for example. However, for the convenience of understanding and explanation, the following description will be based on the opening (13a) being formed in a rectangular shape as shown in the drawings. In this case, the long side of the rectangle corresponds to the width direction of the glass ribbon, and the short side of the rectangle corresponds to the thickness direction of the glass ribbon.

[0033] The length of the short side of the opening (13a) may be, for example, 10 mm or less, preferably 5 mm or less, and more preferably 4 mm, but the present invention is not limited thereto.

[0034] The barrier (14) extends from the upper surface of the nozzle (13) toward the interior of the conditioning tank (12). The barrier (14) may be formed integrally with the nozzle (13) or may be formed separately from the nozzle (13) and attached to the nozzle (13).

[0035] The barrier (14) may be positioned adjacent to the long side of the opening (13a). More specifically, the barrier (14) may be positioned spaced apart from the long side of the opening (13a) by a predetermined distance. Additionally, the barrier (14) may be oriented parallel to the long side of the opening (13a).

[0036] The barrier (14) can be formed as a pair and positioned facing each other with an opening (13a) in between.

[0037]

[0038] The barrier (14) may be formed with a width shorter than that of the opening (13a). In other words, the barrier (14) may be formed with a length shorter than that of the long side of the opening (13a). Additionally, the barrier (14) may be positioned in the center relative to the long side of the opening (13a).

[0039] Both ends of the barrier (14) (i.e., both ends parallel to the long side of the opening (13a)) are spaced apart from the side wall of the conditioning tank (12).

[0040] Consequently, the interior of the conditioning tank (12) can be divided by the barrier (14) near the nozzle (13) into a space in front of the barrier (14) (i.e., the space between the barrier (14) and the opening (13a)) and a space behind the barrier (14) (i.e., the space between the barrier (14) and the side wall of the conditioning tank (12), and the space in front of the barrier (14) and the space behind the barrier (14) can be connected through the area between both ends of the barrier (14) and the side wall of the conditioning tank (12).

[0041] In general, devitrification can occur when a melted glass is maintained at a temperature lower than its liquid phase temperature for a certain period of time. The liquid phase temperature refers to the lowest temperature at which a melted glass can be maintained without crystallization, and is also known as the crystallization temperature.

[0042] Such devitrification can occur more easily near the side wall of the conditioning tank (12). According to the above structure, glass melt that is not easily devitrified in the space in front of the barrier (14) can be discharged directly along the long side of the opening (13a). On the other hand, glass melt that is easily devitrified in the space behind the barrier (14) is blocked by the barrier (14) and cannot be discharged directly along the long side of the opening (13a), but is moved to the short side of the opening (13a) and discharged, thereby inducing devitrification to form at both ends in the width direction of the glass ribbon.

[0043] Therefore, by removing both ends of the glass ribbon in the width direction as a subsequent process, a glass ribbon without devitrification can be finally obtained.

[0044] Referring to FIG. 2, the height (H1) of the barrier (14) may be 7% to 10% of the height (H2) of the conditioning tank (12). Here, the height (H2) of the conditioning tank (12) refers to the length between the top of the conditioning tank (12) to which the supply tube (11) is connected and the bottom of the conditioning tank (12) to which the nozzle (13) is connected.

[0045] By ensuring that the height (H1) of the barrier (14) is at least 7% of the height (H2) of the conditioning tank (12), the interior of the conditioning tank (12) near the nozzle (13) can be clearly separated into the space in front of the barrier (14) and the space behind the barrier (14). If the height (H1) of the barrier (14) is too low compared to the height (H2) of the conditioning tank (12), there is a high probability that the glass melt, which may contain devitrification in the space behind the barrier (14), will pass over the barrier (14) and move toward the center of the long side of the opening (13a) to be discharged. Therefore, it may be desirable for the height (H1) of the barrier (14) to be at least 7% of the height (H2) of the conditioning tank (12).

[0046] In addition, by limiting the height (H1) of the barrier (14) to 10% or less of the height (H2) of the conditioning tank (12), the pressure of the glass melt can be maintained appropriately.

[0047] Given the size of the conditioning tank typically used in the field of glass ribbon manufacturing equipment, the height (H1) of the barrier (14) may be 5 mm to 20 mm.

[0048] Referring to FIG. 3, the width (W1) of the barrier (14) may be 90% to 95% of the width (W2) of the opening (13a). Here, "width" refers to the size in the direction parallel to the long side of the opening (13a).

[0049] By ensuring that the width (W1) of the barrier (14) is at least 90% of the width (W1) of the opening (13a), it is possible to ensure that the melted glass in the space behind the barrier (14) moves toward the short side of the opening (13a) and is discharged. If the width (W1) of the barrier (14) is too short compared to the width (W2) of the opening (13a), the likelihood increases that the melted glass in the space behind the barrier (14) will pass both ends of the barrier (14) and move toward the center of the long side of the opening (13a) and be discharged. Therefore, it may be desirable for the width (W1) of the barrier (14) to be at least 90% of the width (W2) of the opening (13a).

[0050] Additionally, by limiting the width (W1) of the barrier (14) to 95% or less of the width (W2) of the opening (13a), the melted glass in the space behind the barrier (14) can be allowed to move smoothly toward the short side of the opening (13a). If the width (W1) of the barrier (14) is too long compared to the width (W2) of the opening (13a), the melted glass in the space behind the barrier (14) is more likely to stagnate and fail to move smoothly toward the short side of the opening (13a) by passing both ends of the barrier (14). Therefore, it may be desirable for the width (W1) of the barrier (14) to be 95% or less of the width (W2) of the opening (13a).

[0051] In addition, the distance (L1) between the central axis parallel to the long side of the opening (13a) and the barrier (14) may be 80% to 90% of the distance (L2) between the central axis parallel to the long side of the opening (13a) and the side wall of the conditioning tank (12).

[0052] By ensuring that the distance (L1) between the central axis parallel to the long side of the opening (13a) and the barrier (14) is at least 80% of the distance (L2) between the central axis parallel to the long side of the opening (13a) and the side wall of the conditioning tank (12), the flow of the glass melt in the space behind the barrier (14) can be properly maintained, while preventing the barrier (14) from being deformed. If the distance (L1) between the central axis parallel to the long side of the opening (13a) and the barrier (14) is too small, the flow of glass melt in the space behind the barrier (14) becomes excessive, resulting in an imbalance between the amount of glass melt discharged from the space in front of the barrier (14) to the long side of the opening (13a) and the amount of glass melt discharged from the space behind the barrier (14) to the short side of the opening (13a), and there is a risk that the barrier (14) may be improperly deformed. Therefore, it may be preferable that the distance (L1) between the central axis parallel to the long side of the opening (13a) and the barrier (14) be at least 80% of the distance (L2) between the central axis parallel to the long side of the opening (13a) and the side wall of the conditioning tank (12).

[0053] In addition, by limiting the distance (L1) between the central axis parallel to the long side of the opening (13a) and the barrier (14) to 90% or less of the distance (L2) between the central axis parallel to the long side of the opening (13a) and the side wall of the conditioning tank (12), the flow of the glass melt in the space behind the barrier (14) can be ensured smoothly. If the distance (L1) between the central axis parallel to the long side of the opening (13a) and the barrier (14) is too large, the flow of the glass melt in the space behind the barrier (14) is weakened, so the devitrification is not properly discharged, and thus the devitrification may grow excessively. Therefore, it may be preferable that the distance (L1) between the central axis parallel to the long side of the opening (13a) and the barrier (14) is 90% or less of the distance (L2) between the central axis parallel to the long side of the opening (13a) and the side wall of the conditioning tank (12).

[0054] The thickness of the barrier (14) may be thicker than the thickness of the side wall of the conditioning tank (12).

[0055] Since the glass melt in the conditioning tank (12) can have a high temperature of about 1,000-1,200°C and a high hydrostatic pressure of about 2 m, if the barrier (14) is too thin, the barrier (14) may be deformed by the glass melt. Therefore, by forming the thickness of the barrier (14) to be greater than the thickness of the side wall of the conditioning tank (12), the barrier (14) can be prevented from being improperly deformed.

[0056] The thickness of the barrier (14) may be, for example, 5 mm or less, preferably 3 mm or less, and more preferably 2 mm, but the present invention is not limited thereto.

[0057] The thickness of the side wall of the conditioning tank (12) may be, for example, 3 mm or less, preferably 2 mm or less, and more preferably 1.5 mm, but the present invention is not limited thereto.

[0058] At least one of the conditioning tank (12), nozzle (13) and barrier (14) can be formed of a platinum-rhodium alloy.

[0059] By using a platinum-rhodium alloy, heat transfer is excellent and oxidation and corrosion resistance can be improved.

[0060] The mass ratio of rhodium in a platinum-rhodium alloy can be 10% to 20%.

[0061] From the perspective of the coefficient of thermal expansion, it may be desirable for the mass ratio of rhodium to be 20%.

[0062] Based on the structure described above, the flow of glass melt being discharged through the opening (13a) of the nozzle (13) in the glass ribbon manufacturing device (10) according to an embodiment of the present invention will be described below.

[0063] The glass melt supplied by the supply tube (11) is adjusted to a temperature suitable for forming a glass ribbon in the conditioning tank (12) and discharged through the opening (13a) of the nozzle (13).

[0064] At this time, the melted glass in the space in front of the barrier (14) can be discharged directly across the long side of the opening (13a) without remaining inside the conditioning tank (12) for a long time, as indicated by the solid arrow in FIG. 4, and can then be rapidly cooled by a separate cooling device placed downstream of the glass manufacturing device (10). Therefore, the area passes rapidly through the crystallization temperature range, so crystals may not form.

[0065] The corresponding area can be formed mainly in the center of the glass ribbon in the width direction.

[0066] On the other hand, the glass melt that may contain the void in the space behind the barrier (14) is discharged by moving past both ends of the barrier (14) to the short side of the opening (13a), as indicated by the dotted arrow in FIG. 4.

[0067] The corresponding area can be formed mainly at both ends in the width direction of the glass ribbon.

[0068] FIG. 5 is a perspective schematic diagram of a glass ribbon (R) manufactured by a glass ribbon manufacturing device (10) according to an embodiment of the present invention.

[0069] Referring to FIG. 5, a glass ribbon (R) manufactured by a glass ribbon manufacturing device (10) according to an embodiment of the present invention may include a central portion (A1) formed by discharging a glass melt across the long side of an opening (13a) in the space in front of the barrier (14), and an edge portion (A2) formed by discharging a glass melt across both ends of the barrier (14) in the space behind the barrier (14) and moving toward the short side of the opening (13a).

[0070] The edge portion (A2) may contain silt, whereas the center portion (A1) does not contain silt.

[0071] Therefore, as a subsequent process, the edge portion (A2) is removed and only the center portion (A1) is left, thereby finally obtaining a glass ribbon without devitrification.

[0072] The glass ribbon manufacturing device described above is merely one of the glass ribbon manufacturing devices according to various embodiments of the present invention. The technical concept of the present invention is not limited to the above embodiments, but includes all scopes that can be easily modified by a person skilled in the art to which the present invention belongs, as described in the claims.

[0073]

[0074] Explanation of the symbols

[0075] 10: Glass ribbon manufacturing device

[0076] 11: Supply tube

[0077] 12: Conditioning tank

[0078] 13: Nozzle

[0079] 13a: opening

[0080] 14: Barrier

[0081] R: Glass ribbon

[0082] A1: Center

[0083] A2: Edge

Claims

1. A conditioning tank for holding molten glass; A nozzle coupled to the bottom of the above-mentioned conditioning tank and including an opening for discharging melted glass; A barrier disposed around the above-mentioned opening, Glass ribbon manufacturing device.

2. In Paragraph 1, The above opening includes a short side and a long side, and The above barrier is positioned adjacent to the long side of the opening, Glass ribbon manufacturing device.

3. In Paragraph 1, The height of the barrier is 7% to 10% of the height of the side wall of the conditioning tank, Glass ribbon manufacturing device.

4. In Paragraph 2, The width of the barrier is 90% to 95% of the width of the opening, and Here, the width is the length in the direction parallel to the long side of the opening, Glass ribbon manufacturing device.

5. In Paragraph 1, The distance between the nozzle and the barrier is 80% to 90% of the distance between the nozzle and the side wall of the conditioning tank, Glass ribbon manufacturing device.

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