Forming body for forming a continuous glass ribbon and glass forming apparatus including the same

Abstract

This application relates to a forming body for forming a continuous glass ribbon and a glass forming apparatus including the same. The forming body of the disclosed glass forming apparatus has an upper portion, a first forming surface, and a second forming surface that extend downward from the upper portion and converge at a root. The upper portion of the forming body includes a trough for receiving molten glass, the trough including a first weir, a second weir, and a base extending between the weirs. Each weir has a reinforcing portion extending upward from the base toward the top of the weir. The base width of the trough may be less than the top width of the trough. Along the trough length of the trough, the top width, the base width, or the angle between the inner surface of the first or second weir and a vertical plane may be constant.

Description

[0001] This divisional patent application is a divisional application of the patent application with international application number PCT / US2017 / 062692, international filing date November 21, 2017, and national stage entry application number 201780083543.6, with the invention title "Forming Body for Forming a Continuous Glass Ribbon and Glass Forming Apparatus Comprising the Same".

[0002] Cross - reference to related applications

[0003] This application claims the priority of U.S. Provisional Application Serial No. 62 / 425,295, filed on November 22, 2016, the entire content of which is incorporated herein by reference, as detailed below. Background of the Invention Technical Field

[0005] This specification generally relates to forming bodies for producing continuous glass ribbons, and more particularly, to forming bodies that mitigate the outward bowing of the dams of the forming bodies. Technical Background

[0007] The fusion process is a technique for forming glass ribbons. Compared to other processes for forming glass ribbons (e.g., the float process and the slot - draw process), the glass ribbons produced by the fusion process have fewer defects and an excellent flatness on the surface. As a result, the fusion process is widely used to produce glass substrates for LED and LCD display manufacturers and other substrates that require excellent flatness.

[0008] In the fusion process, molten glass is fed into a forming body (also referred to as an overflow trough) that includes forming surfaces that converge at a root. The molten glass flows uniformly over the forming surfaces of the forming body and forms a flat glass ribbon with a pristine surface, which is pulled from the root of the forming body.

[0009] Forming bodies are typically made of refractory materials (e.g., refractory ceramics) that can withstand the high temperatures of the melting process. However, at elevated temperatures, the mechanical properties of even the most temperature - stable refractory ceramics can deteriorate over time, potentially leading to a deterioration of the properties of the glass ribbons produced therefrom, or even to the failure of the forming body. Either situation can lead to disruption of the fusion process, reduced productivity, and increased production costs.

[0010] Accordingly, there is a need for alternative methods and devices for mitigating the deterioration of forming bodies of glass forming apparatuses. Summary of the Invention

[0011] In one or more embodiments of the present disclosure, the forming body of the disclosed glass forming apparatus includes a trough for receiving molten glass. The trough includes a first weir, a second weir spaced apart from the first weir, a base extending between the first and second weirs, an inlet end, a distal end opposite the inlet end, and a trough length. The forming body may include a first forming surface and a second forming surface that converge at the root of the forming body. The first and second forming surfaces may extend, for example, from an upper portion of the forming body. The trough may be disposed, for example, in the upper portion of the forming body. The first and second weirs may each include a top and an inclined inner surface that is oriented at an angle relative to a vertical plane. The first and second weirs may also each include a reinforcing portion that extends upward from the base toward the top. The width of the base of the trough may be less than the width of the top of the trough such that, for at least a portion of the trough length, the cross-section of the trough is trapezoidal. The width of the top of the trough may be constant from the inlet end to the distal end of the trough, and the angle between the inclined inner surface and the vertical plane may vary along at least a portion of the trough length.

[0012] The width of the base of the trough may be constant from the inlet end to the distal end of the trough. Alternatively, the width of the base of the trough may vary along at least a portion of the trough length. For example, the width of the base of the trough may increase from the inlet end of the trough toward the distal end of the trough.

[0013] The angle between the inclined inner surface and the vertical plane may decrease from the inlet end of the trough toward the distal end. Alternatively, the angle between the inclined inner surface and the vertical plane may increase from the inlet end of the trough toward the distal end of the trough.

[0014] At least a portion of the trough length may extend the entire trough length from the inlet end to the distal end of the trough. Alternatively, at least a portion of the trough length may extend from the inlet end of the trough for a distance of 0.25 to 0.5 times the trough length.

[0015] In one or more other embodiments of the present disclosure, the forming body of the disclosed glass forming apparatus may include a trough for receiving molten glass, the trough including a first weir, a second weir spaced apart from the first weir, a base extending between the first weir and the second weir, an inlet end, a distal end opposite the inlet end, and a trough length. The forming body may include a first forming surface and a second forming surface, the first forming surface and the second forming surface converging at the root of the forming body. The first and second forming surfaces may extend, for example, from an upper portion of the forming body. The trough may be disposed, for example, in the upper portion of the forming body. The first weir and the second weir may each include a top having a top thickness and an inclined inner surface oriented at an angle relative to a vertical plane. The first weir and the second weir may also each include a reinforcing portion extending upward from the base toward the top. The width of the base of the trough may be less than the width of the top of the trough such that, for at least a portion of the trough length, the cross-section of the trough is trapezoidal. The width of the base of the trough may be constant from the inlet end to the distal end of the trough, and the width of the top of the trough may vary along at least a portion of the trough length.

[0016] The angle between the inclined inner surface and the vertical plane may be constant from the inlet end to the distal end of the trough. Alternatively, the angle between the inclined inner surface and the vertical plane may vary along at least a portion of the trough length. For example, the angle between the inclined inner surface and the vertical plane may increase from the inlet end of the trough toward the distal end of the trough.

[0017] The width of the top of the trough may decrease from the inlet end to the distal end of the trough. Alternatively, the width of the top of the trough may increase from the inlet end to the distal end of the trough.

[0018] In other embodiments of the present disclosure, the forming body of the disclosed glass forming apparatus may include a trough for receiving molten glass, the trough including a first weir, a second weir spaced apart from the first weir, a base extending between the first weir and the second weir, an inlet end, a distal end opposite the inlet end, and a trough length. The forming body may include a first forming surface and a second forming surface, the first forming surface and the second forming surface converging at the root of the forming body. The first and second forming surfaces may extend, for example, from an upper portion of the forming body. The trough may be disposed, for example, in the upper portion of the forming body. The first weir and the second weir may each include a top having a top thickness and an inclined inner surface oriented at an angle relative to a vertical plane. The first weir and the second weir may also each include a reinforcing portion extending upward from the base toward the top. The width of the base of the trough may be less than the width of the top of the trough such that, for at least a portion of the trough length, the cross-section of the trough is trapezoidal. The angle between the inclined inner surface and the vertical plane may be constant from the inlet end to the distal end of the trough, and the width of the base of the trough may vary along at least a portion of the trough length.

[0019] The top width of the slot can be constant from the inlet end to the distal end of the slot. Alternatively, the top width of the slot can vary along at least a portion of the slot length. For example, the top width of the slot can decrease from the inlet end of the slot towards the distal end.

[0020] The width of the base of the slot can decrease from the inlet end of the slot towards the distal end. Alternatively, the width of the base of the slot can increase from the inlet end of the slot towards the distal end.

[0021] In other embodiments of the present disclosure, the forming body of the glass forming device can include a slot for receiving molten glass, the slot including a first weir, a second weir spaced apart from the first weir, a base extending between the first and second weirs, an inlet end, a distal end opposite the inlet end, and a slot length. The forming body can include a first forming surface and a second forming surface that converge at the root of the forming body. The first and second forming surfaces can extend, for example, from an upper portion of the forming body. The slot can be disposed, for example, in the upper portion of the forming body. The first and second weirs can each include a top having a top thickness and an inclined inner surface oriented at an angle relative to a vertical plane. The first and second weirs can also each include a reinforcing portion extending upward from the base towards the top. The width of the base of the slot can be less than the top width of the slot such that, for at least a portion of the slot length, the cross-section of the slot is trapezoidal. The angle between the inclined inner surface and the vertical plane, the top width of the slot, and the width of the base of the slot can vary along at least a portion of the slot length.

[0022] The angle between the inclined inner surface and the vertical plane can increase from the inlet end of the slot towards the distal end of the slot. Alternatively, the angle between the inclined inner surface and the vertical plane can decrease from the inlet end of the slot towards the distal end.

[0023] The top width of the slot can increase from the inlet end of the slot towards the distal end. Alternatively, the top width of the slot can decrease from the inlet end of the slot towards the distal end.

[0024] The width of the base of the slot can increase from the inlet end of the slot towards the distal end. Alternatively, the width of the base of the slot can decrease from the inlet end of the slot towards the distal end.

[0025] In another embodiment of the present disclosure, the forming body for a glass forming device can include a trough for receiving molten glass, the trough including a first weir, a second weir spaced apart from the first weir, a base extending between the first weir and the second weir, an inlet end, a distal end opposite the inlet end, and a trough length. The forming body can include a first forming surface and a second forming surface that converge at the root of the forming body. The first and second forming surfaces can extend, for example, from an upper portion of the forming body. The trough can be disposed, for example, in the upper portion of the forming body. The first weir and the second weir can each include a top having a top thickness, and a reinforcing portion extending upward from the base toward the top. Each reinforcing portion can have a curved inner surface, and the base of the trough can extend between the curved inner surfaces of the first weir and the second weir. Along at least a portion of the trough length, the width of the base of the trough can be less than the top width of the trough.

[0026] The reinforcing portion of the first weir can extend from the base of the trough to the top of the first weir, and the reinforcing portion of the second weir can extend from the base of the trough to the top of the second weir. The first weir and the second weir can each include a vertical portion extending from the reinforcing portion to the top of the first weir and the second weir. The vertical portion can have a vertical inner surface. Along at least a portion of the trough length, the ratio of the height of the reinforcing portion to the weir height can decrease from the inlet end of the trough toward the distal end.

[0027] The curvature of the curved inner surface can vary along at least a portion of the trough length. For example, the curvature of the curved inner surface can decrease along at least a portion of the trough length. The curvature of the curved inner surface can be a concave curvature. The curvature of the curved inner surface can also be a parabolic curvature. The weir thickness at each point along the parabolic curvature of the curved inner surface can be proportional to the bending stress applied to the first weir or the second weir due to the molten glass flowing through the trough.

[0028] It is to be understood that the foregoing general description and the following detailed description both describe various embodiments and are intended to provide an overall review or framework for understanding the nature and characteristics of the claimed subject matter. The included drawings provide a further understanding of the various embodiments, and the drawings are incorporated into and constitute a part of this specification. The drawings illustrate the various embodiments described herein and, together with the description, are used to explain the principles and operations of the claimed subject matter. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 Schematically shows a glass forming device according to one or more embodiments shown and described herein;

[0030] FIG. 2A schematically shows a conventional forming body for a glass forming device;

[0031] FIG. 2B schematically shows a cross-section of the conventional formed body of FIG. 2A taken along section line 2B-2B;

[0032] Figure 2C Schematically shows a top view of the conventional formed body of FIG. 2A;

[0033] Figure 3 Is a graph of the cross-sectional area (x-axis) versus hydraulic diameter (y-axis) for five flow-equivalent moment-forming bodies having different slot scales but the same mass flow rate over the weir;

[0034] Figure 4A Schematically shows a side view of a formed body according to one or more embodiments shown and described herein;

[0035] Figure 4B Schematically shows according to one or more embodiments shown and described herein Figure 4A of the formed body;

[0036] Figure 4C Schematically shows according to one or more embodiments shown and described herein Figure 4A of another embodiment of the formed body;

[0037] Figure 4D Schematically shows according to one or more embodiments shown and described herein, Figure 4A of the formed body taken along section line 4D-4D closest to the inlet end of the formed body;

[0038] Figure 4E Schematically shows according to one or more embodiments shown and described herein, Figure 4A of the formed body taken along section line 4E-4E in the middle of the formed body;

[0039] Figure 4F Schematically shows according to one or more embodiments shown and described herein, Figure 4A of the formed body taken along section line 4F-4F closest to the distal end of the formed body;

[0040] Figure 5A Schematically shows a side view of a formed body according to one or more embodiments shown and described herein;

[0041] Figure 5B Schematically shows according to one or more embodiments shown and described herein Figure 5A of the formed body;

[0042] Figure 5C Schematically shows according to one or more embodiments shown and described herein Figure 5ATop view of another embodiment of the shaped body;

[0043] Figure 5D Schematically showing according to one or more embodiments shown and described herein Figure 5A Cross-section of the shaped body taken along section line 5D-5D closest to the inlet end of the shaped body;

[0044] Figure 5E Schematically showing according to one or more embodiments shown and described herein Figure 5A Cross-section of the shaped body taken along section line 5E-5E in the middle of the shaped body;

[0045] Figure 5F Schematically showing according to one or more embodiments shown and described herein Figure 5A Cross-section of the shaped body taken along section line 5F-5F closest to the distal end of the shaped body;

[0046] Figure 6A Side view of the shaped body schematically showing according to one or more embodiments shown and described herein;

[0047] Figure 6B Schematically showing according to one or more embodiments shown and described herein Figure 4A Top view of the shaped body;

[0048] Figure 6C Schematically showing according to one or more embodiments shown and described herein Figure 6A Top view of another embodiment of the shaped body;

[0049] Figure 6D Schematically showing according to one or more embodiments shown and described herein Figure 6A Cross-section of the shaped body taken along section line 6D-6D closest to the inlet end of the shaped body;

[0050] Figure 6E Schematically showing according to one or more embodiments shown and described herein Figure 6A Cross-section of the shaped body taken along section line 6E-6E in the middle of the shaped body;

[0051] Figure 6F Schematically showing according to one or more embodiments shown and described herein Figure 6A Cross-section of the shaped body taken along section line 6F-6F closest to the distal end of the shaped body;

[0052] Figure 7 is according to one or more embodiments shown and described herein Figures 4A - 4FA graph showing the relative bending stress of the formed body (y-axis) as a function of the weir height (x-axis);

[0053] Figure 8 According to one or more embodiments shown and described herein Figures 5A - 5F A graph showing the weir spreading rate (y-axis) of a forming body as a function of the relative length from the far end of the groove (x-axis);

[0054] Figure 9 According to one or more embodiments shown and described herein, after a period of operation, Figures 6A - 6F A graph showing a change in mass flow rate of a shaped body (y-axis) as a function of the relative length of the shaped body from the inlet end of the slot (x-axis); and

[0055] Figure 10 According to one or more embodiments shown and described herein, Figures 5A - 5F A plot of the cross-sectional area (x-axis) versus the hydraulic diameter (y-axis) for five flow-equivalent rectangular forming bodies having different slot dimensions but the same mass flow rate over the weir as well as the same cross-sectional area and hydraulic diameter. DETAILED DESCRIPTION

[0056] Reference will now be made in detail to embodiments of a forming body for a glass forming apparatus, examples of which are illustrated in the accompanying drawings. Whenever possible, the same reference numerals are used throughout the drawings to refer to the same or like parts. An embodiment of a forming body 250 for a glass forming apparatus is shown in FIG. Figures 5A - 5F Schematically shown. In this embodiment, the forming body 250 includes an upper portion 252 having a first forming surface 44 and a second forming surface 45 extending from the upper portion 252. The first forming surface 44 and the second forming surface 45 converge at the bottom edge (root 46) of the forming body 250. A trough 251 for receiving molten glass is placed in the upper portion 252 of the forming body 250. The trough 251 includes a first weir 260, a second weir 280 spaced apart from the first weir 260, and a base 253 extending between the first weir 260 and the second weir 280. The trough 251 also includes an inlet end 40, a distal end 42 opposite to the inlet end, and a trough length L T The first weir 260 and the second weir 280 may each include a top 263 and a reinforcement portion 266 extending upward from the base 253 toward the top 263, and an inclined inner surface 261 oriented at an angle α relative to the vertical plane 264. The width W of the base of the trough 251 B It can be smaller than the top width W of the groove 251 T , so that at least for a portion of the slot length L T, the cross-section of the groove 251 is trapezoidal. The top width W of the groove 251 T may be constant from the inlet end 40 to the distal end 42 of the groove 251, and the angle α between the inclined inner surface and the vertical plane 264 may vary along at least a part of the groove length L T The various embodiments of the forming body for a glass forming apparatus will be specifically described below in conjunction with the accompanying drawings.

[0057] The directional terms used herein, such as up, down, left, right, front, back, top, bottom, are only with reference to the drawings drawn and are not used to represent an absolute orientation.

[0058] Unless otherwise stated, none of the methods described herein are intended to be understood as requiring their steps to be performed in a specific order, nor are any devices required to have a specific orientation. Thus, when a method claim does not actually recite that its steps follow a certain order, or any apparatus claim does not actually recite the order or orientation of individual components, or it is not otherwise specifically indicated in the claims or the specification that the steps are limited to a specific order, or the specific order or orientation of the components of the apparatus is not stated, no order or orientation is intended to be implied in any respect. This also applies to any possible basis for interpretation not explicitly stated, including: logic regarding the arrangement of steps, the operation flow, the order of components or the orientation of components; the general meaning obtained from the grammatical structure or punctuation; and the number or type of embodiments described in the specification.

[0059] Unless the context clearly indicates otherwise, as used herein, the singular forms "a", "an" and "the" include plural referents. Thus, for example, reference to "a" component includes embodiments having two or more such components, unless the text clearly indicates otherwise.

[0060] Now refer to Figure 1 , schematically shows a glass forming apparatus 10 for manufacturing glass articles (e.g., a continuous glass ribbon 12). The glass forming apparatus 10 generally may include a melting vessel 14 that receives batch material 15 from a hopper 16. The batch material 15 may be introduced into the melting vessel 14 by a batch transfer device 17 driven by a motor 18. An optional controller 20 may be provided to activate the motor 18, and a molten glass level probe 22 may be used to measure the level of the glass melt in the riser 24 and transmit the measured information to the controller 20.

[0061] The glass forming apparatus 10 may also include a fining vessel 28 (e.g., a fining tube) connected to the melting vessel 14 by way of a first connecting tube 26. A mixing vessel 32 is connected to the fining vessel 28 by a second connecting tube 30. A delivery vessel 36 is connected to the mixing vessel 32 by a delivery conduit 34. As further shown, a lower conduit 38 is positioned to deliver glass melt from the delivery vessel 36 to an inlet end 40 of the forming body 50. In the embodiments shown and described herein, the forming body 50 is a fused forming vessel, which may be referred to as an overflow trough.

[0062] The melting vessel 14 is typically made of a refractory material (e.g., refractory bricks such as ceramic bricks). The glass forming apparatus 10 may also include components typically made of a conductive refractory metal (e.g., platinum or a platinum-containing metal such as, platinum-rhodium, platinum-iridium, and combinations thereof). Such refractory metals may also include: molybdenum, palladium, rhenium, tantalum, titanium, tungsten, ruthenium, osmium, zirconium and their alloys and / or zirconia. The platinum-containing components may include one or more of the following: the first connecting tube 26, the fining vessel 28, the second connecting tube 30, the riser tube 24, the mixing vessel 32, the delivery conduit 34, the delivery vessel 36, the lower conduit 38, and the inlet end 40.

[0063] Referring now to FIGS. 2A-2C, a conventional forming body 50 generally includes a trough 51, a first forming surface 44, and a second forming surface 45. The trough 51 is located in an upper portion 52 of the forming body 50 and includes a first weir 60, a second weir 80, and a base 53 extending between the first weir 60 and the second weir 80. Along the forming body 50, the depth of the trough 51 (i.e., the weir height H W ) may vary as a function of the length L. The first forming surface 44 and the second forming surface 45 extend from the upper portion 52 of the forming body 50 in a vertically downward direction (i.e., the -Z direction of the coordinate axes shown in the figures) and converge towards each other, joining at a lower edge (bottom edge, which may be referred to as the root 46) of the forming body 50. Thus, it should be understood that in some embodiments, the first forming surface 44 and the second forming surface 45 may form an inverted isosceles (or equilateral) triangle extending from the upper portion 52 of the forming body 50, with the root 46 forming the lowest corner point of the triangle in the downstream direction. The draw plane 47 generally bisects the root 46 in the + / −Y direction of the coordinate axes shown in the figures, and the draw plane 47 extends in a vertically downward direction (i.e., the -Z direction) and in the + / −X direction (from the inlet end 40 to the distal end 42 of the forming body 50).

[0064] Referring now to Figures 1 - 2C, during operation, batch material 15 (specifically, batch material for forming glass) is fed from a storage hopper 16 into a melting vessel 14 by a batch transfer device 17. In the melting vessel 14, the batch material 15 is melted into molten glass. The molten glass passes through a first connecting pipe 26 and enters a clarification vessel 28 from the melting vessel 14. In the clarification vessel 28, dissolved gases that may cause glass defects are removed from the molten glass. Then, the molten glass passes through a second connecting pipe 30 and enters a mixing vessel 32 from the clarification vessel 28. The mixing vessel 32 (by stirring, for example) homogenizes the molten glass, and the homogenized molten glass reaches a transfer vessel 36 through a transfer pipe 34. The transfer vessel 36 discharges the homogenized molten glass from a lower conduit 38 and into an inlet end 40 of a forming body 50, which in turn causes the homogenized molten glass to enter a groove 51 of the forming body 50 and lead to a distal end 42 of the forming body 50.

[0065] The homogenized molten glass fills the groove 51 of the forming body 50 and eventually overflows, flowing along the length L of the groove 51 over a first weir 60 and a second weir 80 in an upper portion 52 of the forming body 50. T ( Figure 2C ) and then flows in a vertically downward direction. The homogenized molten glass flows from the upper portion 52 of the forming body 50 and reaches a first forming surface 44 and a second forming surface 45. Streams of the homogenized molten glass flowing on the first forming surface 44 and the second forming surface 45 join and fuse together at a root 46 to form a glass ribbon 12, which is drawn in a downstream direction on a drawing plane 47 by (not shown) pulling rollers. The glass ribbon 12 can also be further processed downstream of the forming body 50. For example, the glass ribbon 12 can be cut into discrete glass sheets, rolled onto itself, and / or one or more layers of coating can be applied to the glass ribbon 12.

[0066] The forming body 50 is typically formed of a refractory ceramic material that is chemically compatible with the molten glass and can withstand the high temperatures associated with the fusion forming process. However, in other embodiments, part or the entire forming body can be formed of other materials (e.g., metallic materials). Typical ceramic refractory materials that can form the forming body include, but are not limited to: zircon (e.g., zirconium silicate), low creep zircon, silicon carbide, xenotime, and / or alumina-based refractory ceramics. The mass of the molten glass flowing into the groove 51 of the forming body 50 exerts an outward pressure on the weirs 60, 80. This pressure combined with the creep of the refractory ceramic material forming the forming body 50 at elevated temperatures can cause the weirs 60, 80 to gradually bow outward (i.e., in the + / -Y direction of the coordinate axes shown in FIGS. 2A and 2B) during the glass drawing event, which may span several years.

[0067] The outward bowing along the length L of the former 50 may be non-uniform and may be most pronounced at the beginning 1 / 3 of the length L of the former 50 at the distance from the inlet end 40 where the trough 51 is deepest. The outward bowing of the weir may significantly change the glass distribution within the trough 51, reducing the glass flow over the weirs 60, 80 where the bowing is most pronounced and increasing the glass flow over the weirs 60, 80 where the bowing is less pronounced. This results in undesirable thickness and width variations in the resulting glass ribbon 12 ( Figure 1 ), which in turn may lead to process inefficiencies due to the rejection of off-specification glass ribbons. Due to the progression of the bowing over time, the use of the former 50 may be interrupted and the glass forming equipment rebuilt due to the deterioration of the glass quality of the outward bow.

[0068] In addition, certain types of glass may need to be processed at very high temperatures (e.g., greater than 1300 °C), and these high temperatures may accelerate the creep of the material of the former 50. This accelerated creep may have a negative impact on the long-term dimensional stability of the former 50, which may reduce the life of the former 50. A conventional solution to mitigate creep is to construct the former 50 from a material with enhanced thermal stability, which may significantly increase the capital cost of the former 50. In addition, due to the increasing demand for fusion formed glass, larger formers 50 may be employed to produce greater glass mass flow rates and increase the yield of the fusion forming process, as well as increase the width of the resulting glass ribbon. Increasing the glass mass flow rate from the former 50 may require an increase in the volume of the former 50, which in turn places additional hydraulic stress on the weirs and may further reinforce the outward bow of the weirs. Constructing a larger former 50 may require a larger refractory blank, increasing the manufacturing cost of the former 50 and the glass sheets formed from such formers.

[0069] Figures 2A - 2C generally show a conventional forming body 50 having a slot 51 defined by a first weir 60, a second weir 80 spaced apart from the first weir 60, and a base 53 extending between the first weir 60 and the second weir 80. The forming body 50 shown in Figures 2A - 2C is before being used in a forming apparatus 10 and before any weir bowing occurs. The forming body 50 has an outer width W2 measured from a first outer surface 62 of the first weir 60 to a second outer surface 82 of the second weir 80. The outer width W2 of the forming body 50 is constant from the first forming surface 44 and the second forming surface 45 to the tops 63 of the first and second weirs 60, 80, and from the inlet end 40 to the distal end 42 of the slot 51. The three - dimensional outer shape defined by the first outer surface 62 of the first weir 60, the first forming surface 44, the second forming surface 45, and the second outer surface 82 of the second weir 80 has an outer width W2 and a height distribution in which the upper - part height H of the forming body 50 measured from the junction 48 between the first forming surface 44 and the first outer surface 62 or from the junction 48 between the second forming surface 45 and the second outer surface 82 U gradually decreases from the inlet end 40 to the distal end 42 of the forming body 50.

[0070] In the forming body 50 shown in Figures 2A - 2C, the slot 51 has a rectangular cross - section extending from the inlet end 40 to the distal end 42 of the forming body 50. In its initial state (i.e., before the forming body 50 is used in a glass - forming apparatus), the inner width W1 of the rectangular slot 51 is constant from the base 53 of the slot 51 to the tops 63 of the first weir 60 and the second weir 80 and from the inlet end 40 to the distal end 42 of the slot 51. That is, the cross - section of the slot 51 is rectangular in a vertical cross - section. Unless otherwise indicated in this disclosure, the vertical cross - section of a feature (e.g., the slot 51) refers to a cross - section taken along a reference plane parallel to the Y - Z plane of the coordinate axes shown in Figure 2B, and the vertical cross - sectional area of a feature refers to the area of that feature in that vertical cross - section. The first weir 60 and the second weir 80 are vertical (i.e., parallel to the X - Z plane of the coordinate axes shown in Figure 2B) and parallel to each other. The first weir 60 is rectangular in a vertical cross - section and has a constant weir thickness T1 from the base 53 of the slot 51 to the top 63 of the first weir 60 and from the inlet end 40 to the distal end 42 of the slot 51. The second weir 80 is also rectangular in a vertical cross - section and has a constant weir thickness T2 from the base 53 of the slot 51 to the top 63 of the second weir 80 and from the inlet end 40 to the distal end 42 of the slot 51. The vertical cross - sectional area of the slot 51 at any point along the length L of the forming body 50 can be calculated by multiplying the inner width W1 by the weir height H of the slot 51. As used in this disclosure, the weir height H W refers to the height of the first or second weir 60, 80 along the slot length L W T ​The height at any point, and typically can be equal to or less than the inlet weir height at the inlet end 40 of the slot 51. Additionally, for the shaped body 50, along the slot length L T The hydraulic diameter at any point can be defined as the cross-sectional area of the shaped body 50 at that point divided by the wetted perimeter of the shaped body 50 at that point. For a slot 51 with a rectangular vertical cross-section, the cross-sectional area is equal to the weir height H W multiplied by the inner width W1. The wetted perimeter can be 2 times the weir height H W plus the inner width W1. Thus, the hydraulic diameter of the rectangular shaped body 50 at any point along the weir length L T can be defined as (H W *W1) / (2*H W +W1).

[0071] See Figure 3 , for several shaped bodies 50 with a rectangular-shaped slot 51, a graph of the hydraulic diameter of the slot 51 versus the vertical cross-sectional area of the slot 51 is plotted. Figure 3 The shaped body 50 represented has the same glass mass flow rate on the first and second weirs 60, 80, but has different cross-sectional areas defined by different inner widths W1 and different inlet weir heights, where the inlet weir height is the weir height H w measured at the inlet end of the shaped body 50. For each rectangular shaped body 50, at a constant longitudinal position (i.e., in the + / -X direction) along the length L of the shaped body 50 from the inlet end 40 to the distal end 42 of the shaped body 50, the vertical cross-sectional area and the hydraulic diameter are determined. At a specific glass mass flow rate, for the flow-equivalent rectangular shaped bodies 50 with a rectangular slot 51, the trend line fitting of the vertical cross-sectional area and hydraulic diameter data results in a flow-equivalent curve 90. Moving from left to right along the flow-equivalent curve 90, the inner width W1 of the slot 51 decreases, and the weir height H W increases. As the vertical cross-sectional area increases, the hydraulic diameter decreases. Regardless of the cross-sectional shape, shaped bodies having a vertical cross-sectional area and a hydraulic diameter located on Figure 3 the flow-equivalent curve 90 have the same glass mass flow rate on the first and second weirs 60, 80 as the shaped body 50 used to establish Figure 3 the flow-equivalent curve 90, provided that the vertical cross-sectional area and the hydraulic diameter are determined at the same longitudinal position along the slot length L T . For different target glass mass flow rates, different flow-equivalent curves 90 can be established.

[0072] The embodiments of the forming bodies described later in this disclosure will be contrasted with the "flow equivalent rectangular forming body". As used in this disclosure, the phrase "flow equivalent rectangular forming body" refers to the forming body 50 as described above, which has a rectangular shaped trough 51 and whose mass flow rate of glass over the first and second weirs 60, 80 and external shape are similar to the forming bodies 150, 250 (discussed later in this disclosure). Figures 4A - 6F ) are the same in mass flow rate and external shape. The properties of the flow equivalent rectangular forming body 50 discussed herein are specified prior to using the flow equivalent rectangular forming body 50 in the glass forming apparatus 10 (i.e., prior to any outward bowing of the weirs). The first weir 60 and the second weir 80 of the flow equivalent rectangular forming body 50 are vertical and parallel to each other and have weir thicknesses T1, T2 that are equal to the forming bodies 150, 250 ( Figures 4A - 6F The top thickness T of the inlet end 40 of the trough 151, 251 of the first weir 160, 260 and the second weir 180, 280 is T The groove 51 of the flow equivalent rectangular forming body 50 has a rectangular vertical cross section, and / or the first weir 60 and the second weir 80 of the flow equivalent rectangular forming body 50 have a rectangular vertical cross section. The external shape defined by the first outer surface 62, the first forming surface 40, the second forming surface 42 and the second outer surface 82 of the flow equivalent rectangular forming body 50 is the same as the external shape of the forming bodies 150, 250 discussed later in the present disclosure.

[0073] The forming body embodiments described subsequently in the present disclosure slow the onset of outward bowing of the weirs of the forming body compared to a flow-equivalent rectangular forming body, thereby extending the useful life of the forming body and stabilizing the dimensional properties of the glass ribbon 12 formed therefrom ( Figure 1 ). In addition, embodiments of the forming body described subsequently in the present disclosure can provide flow equivalence relative to the conventional flow-equivalent rectangular forming body 50 while still maintaining the outer shape of the forming body (before use in the glass forming apparatus 10) being the same as the outer shape of the flow-equivalent rectangular forming body 50 (before use in the glass forming apparatus 10), thereby maintaining the consistent properties of the glass ribbon 12 formed thereby.

[0074] For each embodiment of the forming body described later in this disclosure, each weir can be reinforced by adding material to the bottom portion of the weir near the base. Adding material to the bottom portion of the weir may change the cross-sectional area and / or flow dynamics of the forming body, which may result in a change in the mass flow rate of the molten glass over the weir of the forming body. Therefore, the thickness T at the top of the first and second weirs can be adjusted. T, the depth of the groove, other geometric profile parameters, or combinations thereof, so as to provide an equivalent mass flow rate on the weir compared to the flow equivalent moment forming body 50 having the same external shape and dimensions. Reinforcing the bottom portion of the weir can provide better resistance to weir expansion, and adjustment of the geometric profile of the groove to maintain flow equivalence can avoid damaging the flow characteristics of the molten glass. In addition, reinforcing the bottom portion of the weir can reduce weir expansion without relying on the compressive force applied to the weir to relieve the bowing.

[0075] Now refer to Figures 4A - 4F , which schematically shows that the forming body 150 includes a groove 151, a first forming surface 44, and a second forming surface 45. For illustrative purposes, the dimensions in Figures 4A - 4F are enlarged. The groove 151 is located in the upper portion 152 of the forming body 150 and includes a base 153 extending between a first weir 160 and a second weir 180. Along the length L of the groove 151 T , the groove 151 becomes shallower in depth from the inlet end 40 to the distal end 42 of the forming body 150. The first forming surface 44 and the second forming surface 45 extend from the upper portion 152 of the forming body 150 in a vertically downward direction (i.e., the -Z direction of the coordinate axes shown in the drawings) and converge towards each other, joining at the root 46 of the forming body 150. Therefore, it should be understood that in some embodiments, the first forming surface 44 and the second forming surface 45 may form an inverted (isosceles or equilateral) triangle extending from the upper portion 152 of the forming body 150, and the root 46 forms the lowest corner point of the triangle in the vertically downward direction. The drawing plane 47 generally bisects the root 46 in the + / −Y direction of the coordinate axes shown in the drawings, and the drawing plane 47 extends in the vertically downward direction and in the + / −X direction (from the inlet end 40 to the distal end 42 of the forming body 150).

[0076] Refer to Figures 4D - 4F , the first weir 160 includes a first inner surface 161, a first outer surface 162, and a top 163 extending between the first inner surface 161 and the first outer surface 162. The first inner surface 161 extends from the base 153 of the groove 151 to the top 163 of the first weir 160, and the first outer surface 162 extends substantially vertically (i.e., the + / −Z direction) between the first forming surface 44 and the top 163 of the first weir 160. The upper portion height H of the first outer surface 162 from the first forming surface 44 to the top 163 of the first weir 160 Udecreases from the inlet end 40 to the distal end 42 of the shaped body 150 to define the height profile of the upper portion 152 of the shaped body 150. The first outer surface 162 has a shape defined from the first forming surface 44 of the first weir 160 to the top 163 and from the inlet end 40 to the distal end 42 of the shaped body 150. The second outer surface 182 has a shape defined from the second forming surface 45 of the second weir 180 to the top 163 and from the inlet end 40 to the distal end 42 of the shaped body 150. The shape of the first outer surface 162 is the same as the shape of the second outer surface 182, and the first outer surface 162 and the second outer surface 182 are parallel and perpendicular to the X-Z plane defined by the coordinate axes in Figures 4A - 4F The coordinate axes in the figure. The shape of the first outer surface 162 and the second outer surface 182 of the shaped body 150 may be the same as the first outer surface 62 (FIG. 2B) and the second outer surface 82 (FIG. 2B) of the flow equivalent moment forming body 50 (of FIG. 2B), wherein the first outer surface 62 (FIG. 2B) and the second outer surface 82 (FIG. 2B) are parallel and perpendicular to the X-Z plane defined by the coordinate axes in FIGS. 2A-2B.

[0077] The first weir 160 includes a reinforcing portion 166 that is close to the base 153 and extends upward (i.e., in the +Z direction) toward the top 163 of the first weir 160. The first weir 160 has a weir thickness T, which is measured from the first inner surface 161 to the first outer surface 162 in the + / −Y direction of the coordinate axes in Figure 4D -F. In the reinforcing portion 166, the maximum reinforcing thickness T of the first weir 160 measured close to the base 153 of the groove 151 R may be greater than the top thickness T measured at the top 163 of the first weir 160 T . In one or more embodiments, the weir thickness T decreases from the maximum reinforcing thickness T at the base 153 of the groove 151 R upward in the +Z direction to the top thickness T close to the top 163 of the first weir 160 T may be decreased. In one or more embodiments, the first weir 160 may have a vertical portion 168 that extends downward from the top 163 of the first weir 160 to the reinforcing portion 166 of the first weir 160. The weir thickness T may be constant in the vertical portion 168 of the first weir 160 and may be the same as the top thickness T of the first weir 160 T .

[0078] The reinforcing height H of the first weir 160 RIs defined as the vertical distance from the base 153 of the slot 151 to the upper end of the reinforcement portion 166. The upper end of the reinforcement portion 166 can be the top 163 of the first weir 160, or can be the transition point between the reinforcement portion 166 and the vertical portion 168. The weir thickness T can be the maximum reinforcement thickness T at the base 153 of the slot 151 R To the upper end of the reinforcement portion 166 is gradually decreasing. For example, in one or more embodiments, the upper end of the reinforcement portion 166 can be the top 163 of the first weir 160, so that the reinforcement height H R Can be equal to the weir height H W , and the weir thickness T can be the maximum reinforcement thickness T at the base 153 of the slot 151 R To the top thickness T at the top 163 of the first weir 160 T Is gradually decreasing. Alternatively, in other embodiments, the upper end of the reinforcement portion 166 can correspond to the transition point between the reinforcement portion 166 and the vertical portion 168, which is close to the top 163 of the first weir 160. The reinforcement height H R Can be less than the weir height H W , and the weir thickness T can be the maximum reinforcement thickness T at the base 153 of the slot 151 R To the transition point is gradually decreasing, at which the weir thickness T can be equal to the top thickness T T , and then can remain constant from the transition point to the top 163 of the first weir 160.

[0079] Reinforcement height H R Can be along the slot length L of the slot 151 T From the inlet end 40 to the distal end 42 is decreasing, as Figures 4D to 4E Then to Figure 4F Gradually shown. The slot length L T Can be defined as the longitudinal distance from the inlet end 40 of the formed body 150 to the end of the slot 151 at the distal end 42 of the formed body 150, at the end of the slot 151 at the distal end 42 of the formed body 150, the weir height H W Decreases to zero. In one or more embodiments, the decrease in the reinforcement height H R Can be proportional to the decrease in the weir height H T Along the length L of the slot 151 W Of the weir height H R / H W Is defined as the reinforcement height H R Ratio to the weir height H W . In an embodiment, the reinforcement height ratio H R / H W Along the length L of the slot 151 Tcan be constant. Alternatively, in one or more embodiments, along the slot length L T from the inlet end 40 to the distal end 42 of the slot 151, the reinforcement height H per unit length R can decrease faster than the weir height H W That is, along the slot length L T from the inlet end 40 to the distal end 42 of the slot 151, the reinforcement height H per unit length of the slot 151 R can decrease at a rate greater than the weir height H per unit length of the slot 151 W In these embodiments, from the inlet end 40 to the distal end 42 of the slot 151, the reinforcement height ratio H R / H W can be decreasing.

[0080] See Figure 4B and 4D -4F, in one or more embodiments, the maximum reinforcement thickness T at the base 151 of the slot 150 R from the inlet end 40 to the distal end 42 of the slot 151 can be constant. In other embodiments, the maximum reinforcement thickness T at the base 151 of the slot 150 R from the inlet end 40 to the distal end 42 of the slot 151 can be decreasing. In one or more embodiments, the average weir thickness T A (which is the average of the weir thickness T of the first weir 160 from the base 153 to the top 163) along the slot length L T from the inlet end 40 to the distal end 42 of the slot 151 can be decreasing.

[0081] See Figure 4C , as described above, due to the pressure of the molten glass against the first and second weirs 160, 180, the maximum bending stress on the first and second weirs 160, 180 may exist within the first 1 / 3 of the slot length L of the slot 151 T from the inlet end 40 of the slot 151 towards the distal end 42. Therefore, the reinforcement portion 166 at the beginning 1 / 3 of the slot length L starting from the inlet end 40 of the slot 151 T can provide more benefits for resisting bending stress and reducing weir expansion compared to the distal end 42 of the slot 151, where the slot 151 is shallower and thus the pressure or stress exerted by the molten glass is lower. That is, since the weir height H W from the inlet end 40 to the distal end 42 of the slot 151 is decreasing, the slot 151 is shallower, and the bending stress applied to the first weir 160 and the second weir 180 can be decreasing towards the distal end 42 of the slot 151. In one or more embodiments, the maximum reinforcement thickness T R and the reinforcement height ratio HR / H W Both of these may be reduced along the slot length L T from the inlet end 40 to the distal end 42 of the slot 151, as Figure 4C shown, and as Figures 4D to 4E then to Figure 4F gradually shown.

[0082] For example, in an embodiment, the reinforcement portion 166 may partially extend along the length L of the slot 151 from the inlet end 40 to the distal end 42, as Figure 4C shown. In one or more embodiments, the reinforcement portion 166 may extend from the inlet end 40 of the slot 151 to the longitudinal midpoint 158 of the slot 151. That is, in an embodiment, the reinforcement portion 166 may extend from the inlet end 40 of the slot 151 and may have a reinforcement length L T less than the slot length L R . In some embodiments, the reinforcement length ratio L R / L T may be less than or equal to 0.9, in some embodiments, may be less than or equal to 0.7, in other embodiments, may be less than or equal to 0.5, or even in other embodiments, may be less than or equal to 0.4. In one or more embodiments, the reinforcement length ratio L R / L T may be 0.2 to 0.75, 0.2 to 0.5, 0.2 to 0.4, 0.25 to 0.75, 0.25 to 0.5 or 0.25 to 0.4.

[0083] Alternatively, in one or more embodiments, the reinforcement length L R may be the same as the slot length L T , as Figure 4B shown. In one or more embodiments, the longitudinal midpoint 158 of the slot 151 corresponds to the longitudinal position where L R / L T equals 0.5. In other words, the longitudinal midpoint 158 corresponds to the longitudinal position that is half of the slot length L T from the inlet end 40 to the distal end 42 of the slot 251.

[0084] Referring to Figures 4D - 4F , the inner surface 161 may include a curved section 170 of the reinforcement portion 166 along the first weir 160. The reinforcement height H R of the reinforcement portion 166 is less than the weir height H WIn an embodiment, the inner surface 161 may further have a vertical section 171 extending from the transition point to the top 163 of the first weir 160. Alternatively, the curved section 170 may extend from the base 153 of the groove 151 to the top 163 of the first weir 160. In one or more embodiments, the curvature of the curved section 170 may be concave. The curvature of the curved section 170 may be a parabolic curvature, a circular curvature, an elliptical curvature, or other curved shape or a combination thereof (i.e., a compound curvature). It should be noted that in the accompanying drawings herein, for illustrative purposes, the curvature of the curved sections 170 of the first weir 160 and the second weir 180 is exaggerated.

[0085] The curvature of the curved section 170 may vary along the groove length L T from the inlet end 40 to the distal end 42 of the groove 151. In one or more embodiments, the curvature (e.g., radius of curvature) of the curved section 170 may vary along the groove length L T from the inlet end 40 to the distal end 42 of the groove 151. For example, in an embodiment having a generally circular curvature, the radius of curvature of the curved section 170 may be larger at the inlet end 40 of the groove 151 and T decrease along the groove length L towards the distal end 42 of the groove 151.

[0086] Still referring to Figures 4D - 4F , in one or more embodiments, the curvature of the curved section 170 may be a parabolic curvature. In these embodiments, the stress equation of a cantilever beam fixed at one end under a uniform load may be used to model the bending stress on the first weir 160 and the second weir 180. The stress equation is a parabolic equation, expressed as Equation 1 (Equation 1) below:

[0087]

[0088] In Equation 1, S is the stress on the cantilever beam, F is the uniform load, I is the length of the cantilever beam, x is the distance along the cantilever beam; and only in Equation 1, Z is the section modulus of the cross-section of the beam (i.e., do not confuse with the Z-axis referred to throughout this specification), and Z is equal to I / z, where I is the moment of inertia of the beam and z is the distance from the neutral axis to the extreme edge of the beam. In one or more embodiments, the curvature of the curved section 170 may be modeled to counteract the bending stress exerted by the uniform load of the molten glass pressing on the inner surface 161 of the first weir 160. The weir thickness T of the first weir 160 at each point along the curvature of the inner surface 161 of the first weir 160 may be proportional to the bending stress exerted on the first weir 160 by the molten glass flowing through the groove 151 at each point along the inner surface 161. In these embodiments, the curvature of the curved section 170 may conform to the curvature section defined by the approximate parabolic equation of Equation 2 below:

[0089] y = z 2 / 2 Equation 2

[0090] In Equation 2, y represents the + / -Y position of a point on the bending section 170, and z represents the + / -Z position of a point on the bending section 170. The curvature of the bending section 170 strengthens the first weir 160 and the second weir 180 at the base 153 of the groove 151, relieves the outward bow of the weirs, and improves the dimensional stability of the first and second weirs 160, 180. It should be understood that the same strengthening of the first and second weirs 160, 180 resulting in the relief of the outward bow and the improvement of the dimensional stability of the weirs can be achieved with other curvatures.

[0091] See Figures 4D - 4F , the second weir 180 includes a second inner surface 181, a second outer surface 182, and a top 163 extending between the second inner surface 181 and the second outer surface 182. The second weir 180, the second inner surface 181, and the second outer surface 182 may respectively exhibit one or more of the characteristics described above for the first weir 160, the first inner surface 161, and the first outer surface 162. In one or more embodiments, the second weir 180 may be a mirror image of the first weir 160 and may have the same scale as the first weir 160 along the groove length L T along the groove length L.

[0092] In Figures 4A - 4F the illustrated embodiment of the shaped body 150, the groove 151 formed by the first weir 160, the second weir 180, and the base 153 has an outer width W measured from the first outer surface 162 to the second outer surface 182 O , the outer width W O is constant along the groove length L T longitudinally from the inlet end 40 to the distal end 42 of the groove 151 (i.e., the + / -X direction) and along the height H of the upper portion 152 U vertically from the junction 48 of the upper portion 152 with the first and second shaping surfaces 44, 45 to the top 163 of the first weir 160 and the second weir 180 (i.e., the + / -Z direction). The groove 151 has a top inner width W measured at the top 163 of the first and second weirs 160, 180, between the first inner surface 161 of the first weir 160 and the second inner surface 181 of the second weir 180 T . The top inner width W T may be constant along the groove length L T from the inlet end 40 to the distal end 42 of the groove 151.

[0093] Still see Figures 4D - 4FThe base 153 may be a flat surface that is substantially orthogonal to the first outer surface 162 and the second outer surface 182 (ie, substantially orthogonal to the first outer surface 162 and the second outer surface 182). Figures 4A - 4F The bottom inner width of the groove 151 can be approximately perpendicular to the base width W measured between the reinforcement portion 166 of the first weir 160 and the second weir 180. B In one or more embodiments, the base width W at the inlet end 40 of the slot 151 is B may be smaller than the base width W at the distal end 42 of the slot 151 B That is, in one or more embodiments, the base width W of the groove 151 is B It can be along the slot length L T The groove 151 is increased from the inlet end 40 to the distal end 42. In one or more embodiments, the reinforcement portion 166 of the first weir 160 and the second weir 180 can be located at the center line C of the groove 151. L meet( Figure 4B ), so that the bottom of the trough 151 is continuously curved from the first weir 160 to the second weir 180, and the base width W B Can be zero.

[0094] In one or more embodiments, the average inner width of the trough 151 (which is the average of the width of the trough 151 from the base 153 to the top 163 of the first weir 160 and the second weir 180) is measured along the trough length L. T The slot 151 may be constant from the inlet end 40 to the distal end 42. In other embodiments, the average inner width of the slot 151 at the inlet end 40 may be greater than the average inner width of the slot 151 at the distal end 42 of the slot 151. That is, in one or more embodiments, the average inner width of the slot 151 may be constant along the slot length L. T The groove 151 increases from the inlet end 40 to the distal end 42 .

[0095] The first and second weirs 160, 180 have a curved reinforcement portion 166. Figures 4A - 4F The embodiment of the forming body 150 shown schematically can have the same external shape and mass flow rate as the external shape and mass flow rate of the flow equivalent rectangular forming body 50 (Figures 2A-2C) at the first and second weirs 160, 180, while reducing the outward bowing of the weir present in the flow equivalent rectangular forming body 50. As described above in the present disclosure, the external shape of the forming body 150 is defined by the first outer surface 162, the first forming surface 44, the second forming surface 45, and the second outer surface 182 of the forming body 150. In the embodiment described herein, the length L and the outer width W of the forming body 150 are Omay be the same as the length L and the outer width W2 (FIG. 2B) of the flow equivalent moment forming body 50. Further, the height H of the upper portion of the forming body 150 at each point along the length of the forming body 150 from the inlet end 40 to the distal end 42 of the groove 151 U may be the same as the height H of the upper portion of the flow equivalent moment forming body 50 at the same points along the length L of the flow equivalent moment forming body 50 from the inlet end 40 to the distal end 42 U is the same. Maintaining the outer shape of the forming body 150 the same as the outer shape of the flow equivalent moment forming body 50 maintains the fluid dynamics of the molten glass flowing downward from the first outer surface 162 and the first forming surface 44 to the root 46 and from the second outer surface 182 and the second forming surface 45 to the root 46, which can result in the fused formed glass sheet 12( Figure 1 ) being the same as the fused formed glass sheet 12 produced by the flow equivalent moment forming body 50 before any bowing occurs via the weir. However, the curved sections 170 of the first and second weirs 160, 180 of the forming body 150 reinforce the first and second weirs 160, 180 and reduce the bowing of the weirs 160, 180.

[0096] Reinforcing the first and second weirs 160, 180 (i.e., by thickening the first and second weirs 160, 180 at the base 153 of the groove 151) to reduce bowing changes the flow characteristics of the forming body 150. Thus, the first and second weirs 160, 180 should be reinforced in such a way that flow equivalence is maintained when the cross-sectional area of the groove 151 decreases. Completing the reinforcement of the weirs 160, 180 without causing the forming body 150 to deviate from the flow equivalent curve established for a specific glass mass flow rate established for the target glass mass flow rate (e.g., Figure 3The flow equivalent curve shown (90). More specifically, in order to maintain the flow equivalence of the formed body 150 with respect to the flow equivalent moment formed body 50, certain internal dimensions of the groove 151 can be changed or adjusted. The reinforcement part 166 and the bending sections 170 along the first and second inner surfaces 161, 181 of the reinforcement part 166 are introduced, which reduces the length of the flow path of the molten glass from the bottom of the groove 151 (i.e., the base 153 of the groove 151) to the tops 163 of the first and second weirs 160, 180, which in turn reduces the flow resistance of the molten glass from the inlet end 40 of the groove 151 to the tops 163 of the first and second weirs 160, 180. The reduced impedance of the molten glass flowing to the tops 163 of the first and second weirs 160, 180 increases the flow velocity of the molten glass on the tops 163 of the first and second weirs 160, 180, as compared to the flow equivalent moment formed body 50 having the same cross-sectional area. However, in order to compensate for this flow change, the cross-sectional area of the groove 151 can be reduced to increase the flow resistance of the molten glass, thereby reducing the mass flow rate of the molten glass on the first and second weirs 160, 180 to provide the same mass flow rate of molten glass as the flow equivalent moment formed body 50.

[0097] In an embodiment, the vertical cross-sectional area of the groove 151 of the formed body 150 can be reduced by the following means: reducing the weir height H W (i.e., making the groove 151 shallower while maintaining the upper part height H U the same as the flow equivalent moment formed body 50), changing the top thickness T of the first and second weirs 160, 180 T , making other geometric shape changes, or a combination thereof. Thus, the vertical cross-sectional area of the groove 151 is reduced, so that for the groove 151 of the formed body 150, the graph of the hydraulic diameter versus the vertical cross-sectional area remains on the flow equivalent curve at the target glass mass flow rate (e.g., Figure 3 the flow equivalent curve 90 shown), and the flow equivalent curve is generated by the flow equivalent moment formed body 50 having the same molten glass mass flow rate and the same mass flow rate.

[0098] Compared to the flow equivalent moment formed body 50, the formed body 150 can provide better anti-weir extensibility while maintaining the molten glass flow characteristics (i.e., the mass flow and fluid dynamics along the outer surface of the formed body 150). The formed body 150 can also provide better anti-weir extensibility without relying on the application of a compressive force to counteract weir expansion. In addition, by using the bending sections 170 of the reinforcement part 166 along the first and second weirs 160, 180, increased anti-weir extensibility can be achieved with a minimum addition of material to the first and second weirs 160, 180.

[0099] In one or more embodiments, the forming body 150 of the glass forming device 10 includes: an upper portion 152; a first forming surface 44 and a second forming surface 45 extending from the upper portion 152, the first forming surface 44 and the second forming surface 45 converging at a root 46 of the forming body 150; and a trough 151 located in the upper portion 152 of the forming body 150 for receiving molten glass, the trough 151 including a first weir 160, a second weir 180 spaced apart from the first weir 160, and a base 153 extending between the first weir 160 and the second weir 180, the trough 151 further including an inlet end 40 and a distal end 42. The first weir 160 and the second weir 180 each include a top 163 having a top thickness T T and a reinforcing portion 166 extending upward from the base 153 toward the top 163. Each reinforcing portion 166 has a curved inner surface 161, 181. The base 153 of the trough 151 extends between the curved inner surface 161 of the first weir 160 and the curved inner surface 181 of the second weir 180. Along at least a portion of the longitudinal length of the trough 151 (i.e., the trough length L T ), the width W B of the base of the trough 151 is less than the top width W T of the trough 151.

[0100] In an embodiment, the reinforcing portion 166 of the first weir 160 may extend from the base 153 of the trough 151 to the top 163 of the first weir 160, and the reinforcing portion 166 of the second weir 180 may extend from the base 153 of the trough 151 to the top 163 of the second weir 180. In some embodiments, the first weir 160 and the second weir 180 may each include a vertical portion 168 extending from the reinforcing portion 166 to the top 163 of the first weir 160 and the second weir 180, respectively. The vertical portion 168 may have a vertical inner surface 171. In one or more embodiments, along at least a portion of the longitudinal length of the trough 151 (i.e., the trough length L T ), the ratio of the height H R of the reinforcing portion 166 to the weir height H W is decreasing from the inlet end 40 to the distal end 42 of the trough 151.

[0101] In one or more embodiments, the curvature of the curved inner surface 161 can be a concave curvature. Alternatively, in other embodiments, the curvature of the curved inner surface 161 can vary along the longitudinal length of at least a portion of the slot 151. In other embodiments, the curvature of the curved inner surface can be decreasing along the longitudinal length of at least a portion of the slot 151. In some embodiments, the curvature of the curved inner surface 160 can be a parabolic curvature. In some of these embodiments, the weir thickness at each point of the parabolic curvature along the curved inner surfaces 161, 181 can be proportional to the bending stress applied to the first weir 160 or the second weir 180 by the molten glass flowing through the slot 151.

[0102] Referring now Figures 5A - 5F , an alternative embodiment of the shaped body 250 is schematically shown. Similar to the embodiment of the shaped body 150 shown in FIGS. 4A-4F, Figures 5A - 5F the embodiment of the shaped body 250 shown is constructed to mitigate the outward bowing of the weir while maintaining the molten glass flow characteristics relative to a flow equivalent moment shaped body. For illustrative purposes, the dimensions in Figures 5A - 5F are enlarged. In one or more embodiments, the shaped body 250 includes a slot 251 having a trapezoidal-shaped vertical cross-section. The shaped body 250 includes the slot 251, a first shaping surface 44, and a second shaping surface 45. The slot 251 is located in the upper portion 252 of the shaped body 250 and includes a first weir 260, a second weir 280, and a base 253 extending between the first weir 260 and the second weir 280. Along the slot length L T , the slot 251 becomes shallower in depth from the inlet end 40 to the distal end 42 of the slot 251. The first shaping surface 44 and the second shaping surface 45 extend from the upper portion 252 of the shaped body 250 in a vertically downward direction (i.e., the -Z direction of the coordinate axes shown in the drawing) and converge towards each other, joining at the root 46 of the shaped body 250. Thus, it should be understood that in some embodiments, the first shaping surface 44 and the second shaping surface 45 can form an inverted (isosceles or equilateral) triangle extending from the upper portion 252 of the shaped body 250, with the root 46 forming the lowest corner point of the triangle in the vertically downward direction. The drawing plane 47 generally bisects the root 46 in the + / −Y direction of the coordinate axes shown in the drawing, and the drawing plane 47 extends in the vertically downward direction and in the + / −X direction (from the inlet end 40 to the distal end 42 of the shaped body 250).

[0103] See Figures 5D - 5F, the first weir 260 includes a first inner surface 261, a first outer surface 262, and a top 263 extending between the first inner surface 261 and the first outer surface 262. The second weir 280 includes a second inner surface 281, a second outer surface 282, and a top 263 extending between the second inner surface 281 and the second outer surface 282. For ease of explanation, the shapes of the first weir 260 and the second weir 280 will be described with reference to the first weir 260. It is to be understood that the second weir 280 can be a mirror image of the first weir 260 and can have any of the characteristics of the first weir 260 described hereinafter in the present disclosure.

[0104] The first inner surface 261 of the first weir 260 extends from the base 253 of the groove 251 to the top 263 of the first weir 260, and the first outer surface 262 extends vertically (i.e., in the + / -Z direction) between the first forming surface 44 of the first weir 260 and the top 263. The upper portion height H of the first outer surface 262 from the first forming surface 44 of the first weir 260 to the top 263 U decreases from the inlet end 40 to the distal end 42 of the formed body 250 to define the height distribution of the upper portion 252 of the formed body 250. The first outer surface 262 has an outer shape defined from the first forming surface 44 of the first weir 260 to the top 263 and from the inlet end 40 to the distal end 42 of the formed body 250. The second outer surface 282 has a shape defined from the second forming surface 45 of the second weir 280 to the top 263 and from the inlet end 40 to the distal end 42 of the formed body 150. The shape of the first outer surface 262 is the same as the outer shape of the second outer surface 282, and the first outer surface 262 and the second outer surface 282 are parallel and perpendicular to the X-Z plane defined by the coordinate axes in Figures 5A - 5F the drawing. The outer shape of the first outer surface 262 of the formed body 250 can be the same as the outer shape of the first outer surface 62 (in FIGS. 2A-2B) of the flow equivalent moment forming body 50 (in FIGS. 2A-2B), wherein the first outer surface 62 (in FIG. 2B) and the second outer surface 82 (in FIG. 2B) are parallel and perpendicular to the X-Z plane defined by the coordinate axes in FIGS. 2A-2B.

[0105] The first weir 260 includes a reinforcing portion 266 extending upward (i.e., in the +Z direction) from the base 253 toward the top 263 of the first weir 260. The weir thickness T is the thickness of the first weir 260, which is measured in the Figures 5A - 5F + / -Y direction of the coordinate axes in the drawing from the first inner surface 261 to the first outer surface 262. The maximum reinforcing thickness T of the first weir 260 R (which is the weir thickness T measured at the + / -Z position near the base 253 of the groove 251) can be greater than the top thickness T T(which is the weir thickness T measured at the top 263 of the first weir 260). In one or more embodiments, the weir thickness T decreases from the maximum reinforcement thickness T at the base 253 of the channel 251 R in the +Z direction upward along the first weir 260 to the top thickness T near the top 263 of the first weir 260 T and may be gradually decreasing.

[0106] From the top 263 of the first weir 260 to the base 253 of the channel 251 (i.e., in the -Z direction), the first inner surface 261 may be inclined away from the first outer surface 262 (i.e., in the -Y direction). The first inner surface 261 has a slope at any point along the channel length L T defined as the slope of line B, which is a line in the Y-Z plane extending from the base 253 of the channel 251 to the top 263 of the first weir 260 along the first inner surface 261. The slope of line B is defined as the absolute value ΔZ / ΔY; where, ΔZ is the change in the + / -Z direction between two points on line B, and ΔY is the change in the + / -Y direction between the same two points on line B. At each point along the channel length L T and along the channel length L T , the slope of the first inner surface 261 from the base 253 of the channel 251 towards the top 263 of the first weir 260 may be constant, which is consistent with line B being a single straight line. For example, in some embodiments, the first inner surface 261 may be flat, and line B may have a constant slope along the channel length L T (i.e., in the + / -X direction) from the inlet end 40 to the distal end 42 of the channel 251.

[0107] Alternatively, the slope of the first inner surface 261 may vary along the channel length L T from the inlet end 40 to the distal end 42 of the channel 251. In one or more embodiments, the slope of the first inner surface 261 near the inlet end 40 of the channel 251 may be less than the slope of the first inner surface 261 near the distal end 42 of the channel 251. For example, in some embodiments, the slope of the first inner surface 261 may increase along the channel length L T from the inlet end 40 to the distal end 42 of the channel 251. The first inner surface 261 having a slope that varies along the channel length L T may be non-flat and may be twisted along the channel length L T from the inlet end 40 to the distal end 42 of the channel 251. Such that the slope of the first inner surface 261 varies along the channel length L TThe orientation towards the distal end 42 is increased, which reduces the reinforcement of the first weir 260 near the distal end 42 of the trough 251. In this region, the bending stress of the molten glass on the first weir 260 may be significantly less than the case where the bending stress is compared to the bending stress near the inlet end 40 of the trough 251. Due to the reduction of the bending stress, the reinforcement of the first weir 260 and the second weir 280 at the distal end 42 of the trough 251 may not be as useful.

[0108] The slope of the first inner surface 261 can also be characterized as the inclination angle α, which is the angle in the Y-Z plane between the inner surface 261 and a vertical plane parallel to the first outer surface 262. The inclination angle α described above is the same as the angle formed between the vertical plane 264 described above and the line B, and the line B is the line that extends from the base 253 of the trough 251 to the top 263 of the first weir 260 along the first inner surface 261 in the Y-Z plane. From the inlet end 40 to the distal end 42 of the trough 251, the inclination angle α can be greater than zero along at least a part of the inner surface 261. In one or more embodiments, along the trough length L T From the inlet end 40 to the distal end 42 of the trough 251, the inclination angle α can be constant. Alternatively, in other embodiments, the inclination angle α at the inlet end 40 of the trough 251 can be greater than the inclination angle α at the distal end 42 of the trough 251. For example, in an embodiment, along the trough length L T From the inlet end 40 to the distal end 42 of the trough 251, the inclination angle α can be decreasing. Alternatively, in other embodiments, along the trough length L T From the inlet end 40 to the distal end 42 of the trough 251, the inclination angle α can be increasing.

[0109] Still referring to Figures 5D - 5F , the maximum reinforcement thickness T of the first weir 260 measured near the base 253 R can be constant along the trough length L T from the inlet end 40 to the distal end 42 of the trough 251. In one or more embodiments, the top thickness T of the first weir 260 T can be increasing along the trough length L T from the inlet end 40 to the distal end 42 of the trough 251. Figures 5D - 5F Shows the vertical cross-sections of the forming body 250 at the inlet end 40, the middle, and the distal end 42 of the trough 251. The first top thickness T at the inlet end 40 of the trough 251 T1 can be less than the second top thickness T in the middle of the trough T2 , and the second top thickness T T2 can be less than the third top thickness T at the distal end 42 of the trough 251 T3 . In one or more embodiments, the first top thickness T at the inlet end 40 of the trough 251 T1 (Figure 5D ) can be less than the third top thickness T at the distal end 42 of the slot 251 T3 ( Figure 5F ).

[0110] At the maximum reinforcement thickness T R along the slot length L T remaining constant, along the slot length L T increasing the top thickness T of the first weir 260 T can cause the average weir thickness to increase along the slot length L T from the inlet end 40 to the distal end 42 of the slot 251. The average weir thickness is the average thickness of the first weir 260 from the base 253 to the top 263 of the first weir 260. In one or more embodiments, the slope of the first inner surface 261 of the first weir 260 along the slot length L T can be increased, such that for an increasing top thickness T T the average weir thickness along the slot length L T from the inlet end 40 to the distal end 42 of the slot 251 can be constant or can decrease.

[0111] See Figure 5C , as described above, due to the pressure of the molten glass against the first and second weirs 260, 280, the maximum bending stress on the first and second weirs 260, 280 may exist within the first 1 / 3 of the slot length L T from the inlet end 40 of the slot 251 towards the distal end 42. Thus, the maximum reinforcement thickness T of the first weir 160 R at the beginning 1 / 3 of the slot length L starting from the inlet end 40 of the slot 251 T can provide more effective reduction of weir spread compared to the distal end 42 of the slot 251, where the slot 251 is shallower and thus the pressure or stress exerted by the molten glass on the top of the slot is lower. In one or more embodiments, along the slot length L T from the inlet end 40 to the distal end 42 of the slot 251, the maximum reinforcement thickness T R can be decreased. In one or more embodiments, the slope of the first inner surface 261 can be increasing along the slot length L T from the inlet end 40 to the distal end 42 of the slot 251.

[0112] In one or more embodiments, the maximum reinforcement thickness T of the first weir 260 and the second weir 280 R (and thus the reinforcement portion 266) can only be partially extended along the slot length L T from the inlet end 40 to the distal end 42, as Figure 5C shown. For example, in some embodiments, the maximum reinforcement thickness TR can extend from the inlet end 40 of the slot 251 to the longitudinal midpoint 258 of the slot 251. That is, in an embodiment, the maximum reinforcement thickness T R can extend from the inlet end 40 of the slot 251 and can have a reinforcement length L less than the slot length L T of the reinforcement length L R . In some embodiments, the reinforcement length ratio L R / L T can be less than or equal to 0.9, in some embodiments, can be less than or equal to 0.7, in other embodiments, can be less than or equal to 0.5, or even in other embodiments, can be less than or equal to 0.4. In one or more embodiments, the reinforcement length ratio L R / L T can be 0.2 to 0.75, 0.2 to 0.5, 0.2 to 0.4, 0.25 to 0.75, 0.25 to 0.5 or 0.25 to 0.4.

[0113] Alternatively, in one or more embodiments, the reinforcement length L R can be the same as the slot length L T , as Figure 5B shown. In one or more embodiments, the longitudinal midpoint 258 of the slot 251 corresponds to the longitudinal position where L R / L T equals 0.5. In other words, the longitudinal midpoint 258 corresponds to the longitudinal position that is half of the slot length L from the inlet end 40 to the distal end 42 of the slot 251 T .

[0114] As Figures 5D - 5F shown, the second weir 280, the second inner surface 281 and the second outer surface 282 can respectively exhibit one or more of the characteristics described above with respect to the first weir 260, the first inner surface 261 and the first outer surface 262. In one or more embodiments, the second weir 280 can be a mirror image of the first weir 260 and can have the same dimensions as the first weir 260. For the second weir 280, the second inner surface 281 can be inclined away from the second outer surface in the +Y direction (i.e., in a direction opposite to the slope of the first inner surface 261), such that the maximum reinforcement thickness T of the second weir 280 measured at the base 253 R is greater than the top thickness T at the top of the second weir 280 T .

[0115] In as Figures 5A - 5FIn the illustrated embodiment of the shaped body 250, the groove 251 formed by the first inner surface 261, the second inner surface 281, and the base 253 may have a trapezoidal cross-section. The groove 251 formed by the first weir 260, the second weir 280, and the base 253 may have an outer width W measured from the first outer surface 262 to the second outer surface 282. O , the outer width W O along the groove length L of the groove 151 T longitudinally from the inlet end 40 to the distal end 42 of the groove 251 (i.e., in the + / -X direction) and along the upper part height H of the upper part 252 U vertically from the junction 48 of the upper part 252 with the first and second forming surfaces 44, 45 to the tops 263 of the first weir 260 and the second weir 280 is constant. The groove 251 may have a top inner width W measured between the first inner surface 261 and the second inner surface 281 near the tops 263 of the first weir 260 and the second weir 280. T . The top inner width W T may be along the groove length L T decreasing from the inlet end 40 to the distal end 42 of the groove 251.

[0116] In one or more embodiments, the base 253 may be a flat surface that is substantially orthogonal to the first outer surface 262 and the second outer surface 282 (i.e., substantially orthogonal to the X-Z plane defined by the coordinate axes in Figures 5A - 5F ). As described above, the width W of the base B is the width of the base 253 measured between the first inner surface 261 and the second inner surface 281 and represents the inner width of the groove 251 at the bottom of the groove 251. In one or more embodiments, the width W of the base of the groove 251 B may be along the groove length L T constant from the inlet end 40 to the distal end 42 of the groove 251. Alternatively, in other embodiments, the slopes of the first inner surface 261 and the second inner surface 281 may be increasing from the inlet end 40 to the distal end 42 of the groove 251, which may result in the width W of the base B being along the groove length L T increasing from the inlet end 40 to the distal end 42 of the groove 251.

[0117] In one or more embodiments, the average inner width of the groove 251 (which is the average of the widths of the groove 251 from the base 253 of the groove 251 to the tops 263 of the first weir 260 and the second weir 280) along the groove length L TFrom the inlet end 40 to the distal end 42 of the slot 251, it can be decreasing. That is, in an embodiment, the average inner width of the slot 251 at the inlet end 40 can be greater than the average inner width of the slot 251 at the distal end 42 of the slot 251. Alternatively, in other embodiments, the slopes of the first inner surface 261 and the second inner surface 281 can be increasing from the inlet end 40 to the distal end 42 of the slot 251, which can result in the average inner width of the slot 251 along the slot length L T is kept constant or increasing from the inlet end 40 to the distal end 42 of the slot 251. As described above, along the slot length L T , the depth of the slot 251 (i.e., the weir height H W ) can be decreasing from the inlet end 40 to the distal end 42 of the slot 251.

[0118] Now refer to Figures 6A - 6F , which schematically shows an alternative embodiment of the shaped body 250 having a trapezoidal vertical cross-section. Similar to the shaped body 150 shown in FIGS. 4A-4F as described above and Figures 5A - 5F the embodiment of the shaped body 250 shown Figures 6A - 6F the embodiment of the shaped body 250 shown is constructed to relieve the outward bowing of the first and second weirs 260, 280 while maintaining the molten glass flow characteristics relative to the flow equivalent moment shaped body 50. For illustrative purposes, the dimensions in Figures 6A - 6F are enlarged. The shaped body 250 can include a slot 251, a first shaping surface 44, and a second shaping surface 45. The slot 251 includes a first weir 260, a second weir 280, and a base 253 extending between the first weir 260 and the second weir 280. Along the slot length L T of the slot 251, the slot 251 becomes shallower in depth from the inlet end 40 to the distal end 42 of the shaped body 251. The first shaping surface 44 and the second shaping surface 45 extend from the upper part 252 of the shaped body 250 in a vertically downward direction (i.e., Figure 6A the -Z direction of the coordinate axes shown in

[0119] Refer to Figures 6D - 6F , the first weir 260 includes a first inner surface 261, a first outer surface 262, and a top 263 extending between the first inner surface 261 and the first outer surface 262. The second weir 280 includes a second inner surface 281, a second outer surface 282, and a top 263 extending between the second inner surface 281 and the second outer surface 282. For ease of illustration, the shapes of the first weir 260 and the second weir 280 will be described with reference to the first weir 260. It is to be understood that the second weir 280 can be a mirror image of the first weir 260 and can have any of the characteristics of the first weir 260 described subsequently in this disclosure.

[0120] As described above, the first inner surface 261 of the first weir 260 extends from the base 253 of the trough 251 to the top 263 of the first weir 260. The maximum reinforcement thickness T of the first weir 260 R (which is the weir thickness T measured at the + / -Z position near the base 253 of the trough 251) can be greater than the top thickness T T (which is the weir thickness T measured at the top 263 of the first weir 260). The weir thickness T can be from the maximum reinforcement thickness T at the base 253 of the trough 251 R to the top thickness T near the top 263 of the first weir 260 T and is gradually decreasing.

[0121] From the top 263 of the first weir 260 to the base 253 of the trough 251, the first inner surface 261 can be inclined away from the first outer surface 262 in the -Y direction. At each point along the trough length L T along the trough length L T the slope of the first inner surface 261 (i.e., the absolute value ΔZ / ΔY, which defines the slope of line B that extends along the first inner surface 261 from the base 253 of the trough 251 to the top 263 of the first weir 260 in the Y-Z plane) can be constant from the base 253 of the trough 251 towards the top 263 of the first weir 260. In one or more embodiments, the first inner surface 261 can be flat, and line B can have a constant slope along the trough length L T from the inlet end 40 to the distal end 42 of the trough 251. Alternatively, in other embodiments, the slope of the first inner surface 261 can vary along the trough length L T from the inlet end 40 to the distal end 42 of the trough 251.

[0122] In one or more embodiments, the slope of the first inner surface 261 near the inlet end 40 of the trough 251 can be less than the slope of the first inner surface 261 at the distal end 42 of the trough 251. For example, in an embodiment, the slope of the first inner surface 261 can increase along the trough length L T from the inlet end 40 to the distal end 42 of the trough 251. The first inner surface 261 having a slope that varies along the trough length L T can be non-flat and can be twisted along the trough length L T from the inlet end 40 to the distal end 42 of the trough 251. Having the slope of the first inner surface 261 increase towards the distal end 42 of the trough 251 reduces the reinforcement of the first weir 260 near the distal end 42 of the trough 251, where the bending stress of the molten glass on the first weir 260 can be significantly less than in the case of the bending stress near the inlet end 40 of the trough 251.

[0123] The slope of the first inner surface 261 can also be characterized as an inclination angle α, as described above, which is the angle between the first inner surface 261 and a vertical plane 264 parallel to the first outer surface 262. From the inlet end 40 to the distal end 42 of the groove 251, the inclination angle α can be greater than zero along at least a portion of the inner surface 261. In one or more embodiments, along the groove length L T From the inlet end 40 to the distal end 42 of the groove 251, the inclination angle α can be constant. Alternatively, the inclination angle α at the inlet end 40 of the groove 251 can be greater than the inclination angle α at the distal end 42 of the groove 251. For example, in an embodiment, along the groove length L T From the inlet end 40 to the distal end 42 of the groove 251, the inclination angle α can be decreasing. Alternatively, in other embodiments, along the groove length L T From the inlet end 40 to the distal end 42 of the groove 251, the inclination angle α can be increasing.

[0124] Still referring to Figures 6D - 6F , along the groove length L T From the inlet end 40 to the distal end 42 of the groove 251, the top thickness T of the first weir 260 near the top 253 T can be constant. In one or more embodiments, the maximum reinforcement thickness T of the first weir 260 measured near the base 253 R can be along the groove length L T increasing from the inlet end 40 to the distal end 42 of the groove 251. Figures 6D - 6F Shows a vertical cross-section of the formed body 250 at the inlet end 40, middle, and distal end 42 of the groove 251. The first reinforcement thickness T near the inlet end 40 of the groove 251 R1 can be less than the second reinforcement thickness T in the middle of the groove R2 , and the second reinforcement thickness T R2 can be less than the third reinforcement thickness T near the distal end 42 of the groove 251 R3 . In one or more embodiments, the first reinforcement thickness T at the inlet end 40 of the groove 251 R1 ( Figure 6D ) can be less than the third reinforcement thickness T at the distal end 42 of the groove 251 R3 ( Figure 6F ). In one or more embodiments, the top thickness T of the first weir 260 near the inlet end 40 of the groove 251 T can be less than the weir thickness T (FIG. 2B) of the flow equivalent moment forming body 50 (FIGS. 2A-2B).

[0125] At the top thickness T T remaining constant along the groove length L T While remaining constant along the groove length L TReduce the maximum reinforcement thickness T of the first weir 260 R Can cause the average weir thickness to decrease along the trough length L T From the inlet end 40 to the distal end 42 of the trough 251. As described above, the average weir thickness is the average thickness of the first weir 260 from the base 253 to the top 263 of the first weir 260. In one or more embodiments, along the trough length L T , the slope of the first inner surface 261 of the first weir 260 can be increased.

[0126] As Figure 6B And 6D -6F shows, when the top thickness T of the first weir 260 and the second weir 280 remains constant along the trough 251 T , the top inner width W of the trough 251 T Can also remain constant along the trough length L T From the inlet end 40 to the distal end 42 of the trough 251. The width W of the base of the trough 251 B Can increase along the trough length L T From the inlet end 40 to the distal end 42 of the trough 251. As Figures 6D - 6F Shown, in an embodiment, the first base width W near the inlet end 40 of the trough 251 B1 Can be less than the second base width W in the middle of the trough 251 B2 , and the second base width WB2 in the middle of the trough 251 can be less than the third base width W near the distal end 42 of the trough 251 B3 . In an embodiment, along the trough length L T From the inlet end 40 to the distal end 42 of the trough 251, the inclination angle α (i.e., the slope of the first inner surface 261) between the first inner surface 261 and the vertical surface 261 parallel to the first outer surface 262 can be constant. Alternatively, in other embodiments, the inclination angle α between the first inner surface 261 and the vertical surface 261 parallel to the first outer surface 262 can vary from the inlet end 40 to the distal end 42 of the trough 251. In some of these embodiments, the inclination angle α between the first inner surface 261 and the vertical plane 261 parallel to the first outer surface 262 can increase from the inlet end 40 to the distal end 42 of the trough 251, which can cause the width W of the base B To increase at a greater rate along the trough length L T From the inlet end 40 to the distal end 42 of the trough 251, compared to embodiments with a constant inclination angle α or slope of the first inner surface 251.

[0127] In one or more embodiments, the average inner width of the trough 251 (i.e., the average of the widths of the trough 251 from the base 253 to the tops 263 of the first and second weirs 260, 280) along the trough length LT From the inlet end 40 to the distal end 42 of the slot 251, it can be increasing. In one or more embodiments, the average inner width of the slot 251 at the inlet end 40 can be less than the average inner width of the slot 251 at the distal end 42 of the slot 251.

[0128] In Figures 5A - 6F In one or more embodiments of the shaped body 250 shown schematically, the top width W of the slot 251 T can be constant from the inlet end 40 to the distal end 42 of the slot 251, and the angle α between the inclined inner surface 261 and the vertical plane 264 can vary along at least a portion of the slot length L T The angle α between the inclined inner surface 261 and the vertical plane 264 can be decreasing from the inlet end 40 of the slot 251 towards the distal end 42. Alternatively, the angle α between the inclined inner surface 261 and the vertical plane 264 can be increasing from the inlet end 40 of the slot 251 towards the distal end 42. In these embodiments, the width W of the base of the slot 251 B can be constant from the inlet end 40 to the distal end 42 of the slot 251. Alternatively, the width W of the base of the slot 251 B can vary along at least a portion of the slot length L T In some embodiments, the width W of the base of the slot 251 B can be increasing from the inlet end 40 of the slot 251 towards the distal end 42.

[0129] In Figures 5A - 6F In one or more embodiments of the shaped body 250 shown schematically, the width W of the base of the slot 251 B can be constant from the inlet end 40 to the distal end 42 of the slot 251, and the top width W of the slot 25 T can vary along at least a portion of the slot length L T The top width W of the slot 251 T can be decreasing from the inlet end 40 of the slot 251 towards the distal end 42. Alternatively, the top width W of the slot 251 T can be increasing from the inlet end 40 of the slot 251 towards the distal end 42. In these embodiments, the angle α between the inclined inner surface 261 and the vertical plane 264 can be greater than zero and constant from the inlet end 40 to the distal end 42 of the slot 251. Alternatively, the angle α between the inclined inner surface 261 and the vertical plane 264 can vary along at least a portion of the slot length L T In some embodiments, the angle α between the inclined inner surface 261 and the vertical plane 264 can be increasing from the inlet end 40 of the slot 251 towards the distal end 42.

[0130] In Figures 5A - 6FIn one or more additional embodiments of the shaped body 250 shown schematically, the angle α between the inclined inner surface 261 of the groove 251 and the vertical plane 264 can be greater than zero and constant from the entrance end 40 to the distal end 42 of the groove 251, and the width W of the base of the groove 25 B can vary along at least a portion of the groove length L T The width W of the base of the groove 251 B can decrease from the entrance end 40 of the groove 251 towards the distal end 42. Alternatively, the width W of the base of the groove 251 B can increase from the entrance end 40 of the groove 251 towards the distal end 42. In these embodiments, the top width W of the groove 251 T can be constant from the entrance end 40 to the distal end 42 of the groove 251. Alternatively, the top width W of the groove 251 T can vary along at least a portion of the groove length L T In some embodiments, the top width W of the groove 251 T can decrease from the entrance end 40 of the groove 251 towards the distal end 42.

[0131] In one or more embodiments, the angle α between the inclined inner surface 261 and the vertical plane 264, the top width W T and the base width W of the groove 251 B can vary along at least a portion of the groove length L from the entrance end 40 to the distal end 42 of the groove 251 T In some embodiments, the angle α between the inclined inner surface 261 and the vertical plane 264 can increase from the entrance end 40 towards the distal end 42. Alternatively, in some embodiments, the angle α between the inclined inner surface 261 and the vertical plane 264 can decrease from the entrance end 40 towards the distal end 42. In some embodiments, the top width W T can increase from the entrance end 40 towards the distal end 42. Alternatively, in embodiments, the top width W T can decrease from the entrance end 40 towards the distal end 42. In some embodiments, the width W of the base of the groove 251 B can increase from the entrance end 40 towards the distal end 42. Alternatively, in embodiments, the width W of the base of the groove 251 B can decrease from the entrance end 40 towards the distal end 42.

[0132] The groove 251 has a trapezoidal-shaped vertical cross-section Figures 5A - 5FThe embodiments of the formed body 250 schematically shown in FIGS. 6A - 6F can have the same external shape and mass flow rate as the flow - equivalent moment - forming body 50 (FIGS. 2A - 2C) on the first weir 260 and the second weir 280, while reducing the outward bowing of the weirs present in the flow - equivalent moment - forming body 50. See Figure 5A , 5D , FIGS. 6A and 6D and as described above in the present disclosure, the external shape of the formed body 250 is defined by the first outer surface 262, the first forming surface 44, the second forming surface 45, and the second outer surface 282 of the formed body 250. In the embodiments described herein, the length L T and the outer width W O of the formed body 250 can be the same as the length L T and the outer width W2 (FIG. 2B) of the flow - equivalent moment - forming body 50. Additionally, the height H U of the upper portion of the formed body 251 at each point along the length L of the formed body 250 from the inlet end 40 to the distal end 42 of the slot 250 can be the same as the height H U of the upper portion of the flow - equivalent moment - forming body 50 at the same points along the length L of the flow - equivalent moment - forming body 50 from the inlet end 40 to the distal end 42. Maintaining the external shape of the formed body 250 the same as the external shape of the flow - equivalent moment - forming body 50 maintains the hydrodynamics of the molten glass flowing downward from the first outer surface 262 and the first forming surface 44 to the root 46 and from the second outer surface 282 and the second forming surface 45 to the root 46, which can result in a fused - formed glass sheet 12 ( Figure 1 ) being the same as the fused - formed glass sheet 12 produced by the flow - equivalent moment - forming body 50 before any bowing occurs via the weirs. However, the reinforcement portions 266 of the first and second weirs 260, 280 of the formed body 250 reinforce the first and second weirs 260, 280 and reduce the bowing of the weirs 260, 280.

[0133] As described above, the first and second weirs 260, 280 are reinforced (i.e., by thickening the first and second weirs 260, 280 at the base 253 of the slot 251 by incorporating a slot 251 having a trapezoidal - shaped vertical cross - section) to reduce bowing, which changes the flow characteristics of the formed body 250. Therefore, the first and second weirs 260, 280 should be reinforced in such a way that flow equivalence is maintained when the vertical cross - sectional area of the slot 251 is reduced. The first and second weirs 260, 280 are reinforced without causing the formed body 250 to deviate from the flow - equivalent curve established for a target glass mass flow rate (e.g., Figure 3 the flow - equivalent curve 90 shown).

[0134] More specifically, to maintain the flow equivalence of the shaped body 250 relative to the flow equivalent moment shaped body 50, one or more of the internal dimensions of the groove 251, the first weir 260, the second weir 280, the base 253, or a combination thereof may be varied to change the mass flow rate of the molten glass over the first weir 260 and the second weir 280. By incorporating the first inner surface 261 and the second inner surface 281 that are inclined towards the center of the groove 251, the flow path length of the molten glass from the bottom of the groove 251 (i.e., the base 253 of the groove 251) to the tops 263 of the first weir 260 and the second weir 280 can be reduced, which can reduce the impedance to the mass flow of the molten glass from the inlet end 40 of the groove 251 to the tops 263 of the first weir 260 and the second weir 280. As described above, the reduced impedance to the mass flow of the molten glass to the tops 263 of the first weir 260 and the second weir 280 can increase the flow rate of the molten glass over the tops 263 of the first and second weirs 260, 280, as compared to the flow equivalent moment shaped body 50 having the same cross-sectional area. However, to compensate for this change in mass flow, the vertical cross-sectional area of the groove 251 can be further reduced to increase the impedance to the molten glass flowing through the groove 251, thereby reducing the mass flow rate of the molten glass over the first and second weirs 260, 280 to provide the same mass flow rate of the molten glass as the flow equivalent moment shaped body 50.

[0135] In an embodiment, the vertical cross-sectional area of the groove 251 of the shaped body 250 can be reduced by: reducing the weir height H W (i.e., making the groove 251 shallower while maintaining the upper portion height H U the same as the flow equivalent moment shaped body 50), varying the top thickness T of the first and second weirs 260, 280 T , making other geometric profile adjustments, or a combination thereof. Thus, the vertical cross-sectional area of the groove 251 is further reduced such that, for the groove 251 of the shaped body 250, the plot of the hydraulic diameter versus the vertical cross-sectional area remains on the flow equivalent curve for the target glass mass flow rate (e.g., Figure 3 the flow equivalent curve 90 shown), which is generated by the flow equivalent moment shaped body 50 having the same molten glass mass flow rate.

[0136] Compared to the flow equivalent moment shaped body 50, the shaped body 250 having a trapezoidal cross-sectional shape can provide better weir extensibility resistance while maintaining the molten glass flow characteristics (i.e., the mass flow and hydrodynamics along the outer surface of the shaped body 250). The shaped body 250 can also provide better weir extensibility resistance without relying on the application of a compressive force.

[0137] Example

[0138] The embodiments described herein are further illustrated by the following examples. Unless otherwise specified, the examples are based on the mathematical modeling of the formed body using GOMA software.

[0139] Example 1

[0140] For the formed body 150 having the structure shown in Figures 4A - 4F , the bending stress was obtained by modeling calculation. The formed body 150 has a slot width of 8 inches and a slot depth of 12 inches (i.e., the weir height H W ). The shapes of the first inner surface 161 of the first weir 160 and the second inner surface 181 of the second weir 180 conform to the profile generated by the moment curve function of Equation 2. The relative bending stress at the inlet end 40 of the slot 151 was calculated, at which point the weir height H W is the maximum (and thus the bending stress is the maximum). Figure 7 Show Figures 4A - 4F The calculated relative bending stress 702 of the bending weir of the formed body 150. The bending stress of the comparative example of the flow equivalent moment formed body 50 (having a weir thickness T1, T2 of 2 inches) shown in FIGS. 2A and 2B was also modeled. In Figure 7 , the modeling results of the relative bending stress of the flow equivalent moment formed body 50 as the rectangular weir bending stress 704 are also provided. Figure 7 The relative bending stress provided is a function of the distance from the bottom of the slot 151 (i.e., the base 153 of the slot 151).

[0141] As Figure 7 shown, adding a tapered reinforcement greatly reduces the bending stress experienced by the bottom portion of the weir. By increasing the moment of inertia of the area and the section modulus, the tapered reinforcement significantly reduces the stress. The stress in the bottom 3 inches of the weir can be reduced by up to 60% to 75%.

[0142] Example 2

[0143] For the formed body 250 having the structure shown in Figures 5A - 5F (which has a slot 251 with a trapezoidal cross-section), the weir expansion rate was modeled. The weir height H at the inlet end 40 of the slot 251 W was set to 12.95 inches, the top thickness T of the first and second weirs 260, 280 at the inlet end 40 of the slot 251 T was set to 1.025 inches, and the reinforcement thickness T at the inlet end 40 of the slot 251 R was set to 3.525 inches. The base width W of the slot 251 at the inlet end 40 B was set to 4.70 inches. The weir height H W decreases approximately linearly from the inlet end 40 to the distal end 42 of the slot 251, while the base width W Band the inclination angles α of the inner surfaces 261, 281 of the first and second weirs 260, 280 are along the trough length L T which is maintained constant. At the inlet end 40 of the trough 251, the vertical cross-sectional area of the trough 251 is 94 square inches (inches 2 ), and the wetted perimeter of the trough is 31 inches. The calculated hydraulic diameter of the formed body 250 is 12.0 inches. The cross-sectional area vs. hydraulic diameter diagram of the trough 251 is as Figure 10 shown and is designated by reference numeral 290. Figure 10 Also included is a flow equivalent curve 90 of the flow equivalent moment formed body 50. As Figure 10 shown, the cross-sectional area vs. hydraulic diameter diagram 290 of the trough 251 falls on the flow equivalent curve 90, indicating that the glass mass flow on the weirs 260, 280 of the formed body 250 of Example 2 is the same as that of the flow equivalent moment formed body 90 used to establish the flow equivalent curve 90.

[0144] In Figure 8 is provided the function relationship of the modeled annual weir expansion rate with respect to the relative distance from the distal end 42 along the length of the trough 251 (i.e., in Figure 8 , the distal end 42 is set to x = 0), and is designated by reference numeral 802. For comparison, for the flow equivalent moment formed body 50 having a rectangular weir and a rectangular-shaped trough 51 as shown in FIGS. 2A - 2C, the weir expansion rate was modeled. The weir height H W of the flow equivalent moment formed body 50 is 12.95 inches, the weir thicknesses T1, T2 are 2 inches, and the inner width W1 of the trough is 7.75 inches. In Figure 9 is represented by reference numeral 92 the cross-sectional area vs. hydraulic diameter relationship diagram of the flow equivalent moment formed body 50 having a weir height of 12.95 inches and a weir thickness of 2 inches, which falls on the flow equivalent curve 90. The same heat load and mechanical load conditions were used for both models. In Figure 8 is provided the modeled weir expansion rate of the flow equivalent moment formed body 50, designated by reference numeral 804.

[0145] As Figure 8 shown, for the formed body 250 having a trapezoidal trough 251, the weir expansion rate exhibits a maximum weir expansion rate U T at approximately 0.85 relative length from the distal end 42 of the formed body 250 (i.e., 85% of the trough length L T，最大值 ). The comparative example of the flow equivalent moment formed body 50 has a maximum weir expansion rate U R，最大值 at an approximately identical location (relative length of 0.85 from the distal end 42 of the formed body 50). The U exhibited by the formed body 250 having a trapezoidal-shaped trough 251 T，最大值The U of the flow equivalent moment forming body 50 R，最大值 is 63% smaller. Therefore, strengthening the weirs 260, 280 of the forming body 250 to produce a groove 251 with a trapezoidal cross-section can provide a maximum weir expansion rate reduction of up to 63%.

[0146] Comparative Example 1

[0147] After operating at a constant production rate for a fixed period of time, the flow change of the flow equivalent moment forming body 50 is calculated by measuring the actual profile of the weir sag and weir expansion of the rectangular forming body 50 after decommissioning. The flow equivalent moment forming body 50 is made of zircon refractory. In Figure 9 it is graphically shown the functional relationship between the predicted flow change 902 of the flow equivalent moment forming body 50 and the relative distance from the inlet end 40 of the forming body 50. As Figure 9 shown, the maximum flow change 904 (i.e., the maximum absolute value of the flow change) occurs at a relative length of about 0.05 from the inlet end 40 of the forming body 50, at which point it is shown that the glass mass flow on the weir is reduced by more than 8 pounds per hour per inch (lb / h / in).

[0148] Comparative Example 2

[0149] The flow change after the second flow equivalent moment forming body 50 of FIGS. 2A-2C is operated at a constant production rate for a fixed period of time is modeled. The dimensions of the flow equivalent moment forming body 50 of Comparative Example 2 are the same as those of the flow equivalent moment forming body 50 of Comparative Example 1, but in Comparative Example 2, a low creep zircon refractory is used as the construction material for modeling. Compared with the conventional zircon refractory, the low creep zircon refractory exhibits better weir expansion resistance. In Figure 9 it is graphically shown the functional relationship between the modeled flow change 906 of the flow equivalent moment forming body 50 of Comparative Example 2 and the distance from the inlet end 40 of the forming body 50. As Figure 9 shown, the maximum flow change 908 (i.e., the maximum absolute value of the flow change) occurs at a relative length of about 0.05 from the inlet end 40 of the forming body 50, at which point it is shown that the glass mass flow on the weir is reduced by more than 6 lb / h / in. As expected, using a different material with better weir expansion resistance results in the maximum flow change 908 of Comparative Example 2 being less than the maximum flow change 904 of Comparative Example 1.

[0150] Example 3

[0151] Modeling obtains the flow variation after the third flow equivalent moment forming body 50 in FIGS. 2A - 2C operates at a constant production rate for a fixed period of time. The dimensions of the moment forming body 50 in Example 3 are the same as those of the flow equivalent moment forming body 50 in Comparative Example 1, but in Comparative Example 3, low creep zirconia refractory material is used as the construction material for modeling. In addition, the modeling of the third formed body in Example 3 removes the weir extension effect from the simulation to show the positive effect of reducing the weir extension. In Figure 9 FIG. Figure 9 , the model flow variation 910 of the moment forming body in Example 3 is graphically shown as a function of the distance from the inlet end 40 of the forming body 50. As Figure 9 shown, the maximum flow variation 912 (i.e., the maximum absolute value of the flow variation) occurs at a relative length of about 0.05 from the inlet end 40 of the forming body 50, at which point, it is shown that the reduction in the glass mass flow on the first and second weirs 60, 80 is less than 5 pounds per hour per inch. Compared with the maximum flow variation 908 of Comparative Example 2, the maximum flow variation 912 of the forming body 50 in Example 3 from which the weir extension effect is removed from the simulation shows a 45% improvement in the flow variation. Comparative Example 2 is constructed of the same material but includes the weir extension effect in the simulation. Therefore, it is shown that removing the weir extension effect from the simulation results in the service life of the forming body 50 in Example 3 being approximately 1.8 times the service life of the flow equivalent moment forming body 50 in Comparative Example 2.

[0152] For the evaluation of the improvement in service life, it is assumed that no weir extension occurs, which would be the maximum improvement. To evaluate the actual improvement in service life, the maximum service life improvement of 1.8 times the service life of the flow equivalent moment forming body 50 in Comparative Example 2 can be multiplied by the 63% reduction in weir extension in Example 2. The estimated improvement in the service life obtained for the forming body 50 in Example 3 without considering the weir extension is approximately 1.5 times the estimated service life of the flow equivalent moment forming body 50 in Comparative Example 2.

[0153] Based on the above, it should now be understood that the embodiments described herein relate to forming bodies for glass forming equipment. The forming bodies described herein can be constructed to slow down the onset of the outward bowing of the weir of the forming body due to material creep and the pressure of the molten glass against the vertical inner surface of the weir, thereby extending the service life of the forming body.

[0154] Although various embodiments and techniques for slowing down the onset of the outward arching of the weir of the forming body have been described herein, it should be understood that these embodiments and techniques are expected to be used separately or in combination with one or more embodiments and techniques.

[0155] It will be apparent to those skilled in the art that various modifications and variations can be made to the embodiments described herein without departing from the spirit and scope of the subject matter claimed. Accordingly, this specification is intended to cover modifications and variations of the various embodiments described herein that fall within the scope of the appended claims and their equivalents.

Claims

1. A glass forming device, comprising: A forming body, comprising: An upper part, comprising a first outer surface, a second outer surface opposite to the first outer surface, and an outer width measured from the first outer surface to the second outer surface, A trough configured to receive molten glass, which is arranged in an upper part and is formed by a first weir, a second weir and a base extending between the first weir and the second weir, the trough comprising an inlet end, a distal end opposite the inlet end and a length L defined between the inlet end and the distal end T , wherein: The first and second weirs each include: an inclined inner surface extending from the base to the top of the respective weir and a top thickness T at the top of the respective weir T , the inclined inner surface being oriented at an angle relative to the vertical plane, and a reinforcing portion extending upward from the base toward the top of the respective weir, with a maximum reinforcing thickness T near the base R greater than the top thickness T T ; The angle α between the inclined inner surface and the vertical plane increases along at least a portion of the length L of the groove T increases; Reinforcement thickness T R including a reinforcement length L extending along at least a portion of the length L of the slot from the inlet end T and L R , and L R / L T ranges from 0.2 to 0.75; and The length and outer width of the forming body are the same as the length and outer width of a flow equivalent moment forming body.

2. The glass forming device according to claim 1, wherein T R along at least a portion of the length L of the groove T is constant 3. The glass forming device according to claim 2, wherein, T R The average value of T T increases along at least a portion of the length L of the slot, and the average value of R T is defined as the average thickness of the weir measured from the base to the top of the weir.

4. The glass forming device according to claim 1, wherein, T T along at least a portion of the length L of said groove T is increased.

5. The glass forming device according to claim 4, wherein, T R whose average value is constant along at least a part of the length L of said slot T wherein said average value of T R is defined as the average thickness of the weir measured from the base to the top of the weir 6. The glass forming device according to claim 4, wherein, T R The average value of T T along at least a portion of the length L of the slot R is decreased, where the average value of T is defined as the average thickness of the weir measured from the base to the top of the weir.

7. The glass forming device according to claim 1, wherein, The first weir and the second weir each include a weir height H W , and H W along the length L of the trough T is decreasing

Images