JP2017530932A - Method for changing the flow of molten glass and apparatus therefor - Google Patents

Abstract

The method of changing the flow of the molten glass includes a step of flowing the molten glass from the molded body as a molten glass ribbon, and a step of superimposing the molten glass ribbon on a flow member disposed at a distance from the lower edge of the molded body. The flow member extending a predetermined distance from the edge thereof into the molten glass ribbon such that the molten glass flows over opposing first and second major surfaces of the flow member.

Description

Explanation of related applications

  This application claims the benefit of priority of US Provisional Patent Application No. 62 / 060,205, filed Oct. 6, 2014, the contents of which are incorporated herein by reference in their entirety. Claims under 35 USC 119.

  The present disclosure relates generally to molding glass ribbons by a downdraw process, and more specifically to controlling the flow of molten glass drawn from a molded body.

  In one method of forming thin high quality glass for purposes such as the manufacture of display devices, a molten precursor material, hereinafter, molten glass, is flowed from the forming body to form a ribbon of molten glass. When the ribbon descends from the lower edge of the molded body, it is cooled to become an elastic solid glass ribbon. This ribbon can then be cut into separate glass sheets that can be further processed and then transported to the equipment manufacturer.

  As the molten glass ribbon descends from the forming body, the ribbon width decreases and the side edges of the ribbon thicken. This thickened edge portion is generally called a bead. Both of these effects reduce the total usable area of the glass ribbon, resulting in manufacturing loss. Thus, increasing the ribbon width and / or decreasing the size of the unusable edge portion can increase the manufacturing yield.

  In other cases, for example in the case of ultra-thin glass, the size of the side edges themselves rather than the width of the ribbon may be the primary concern.

  The flow of ribbon-like molten glass from the forming body, such as a fusion downdraw or slot draw process forming body, can undergo lateral damping, with the lateral edges of the ribbon being drawn inwardly. . On the other hand, the thickness of the edge portion of the glass ribbon increases due to the decrease in the horizontal range. This can create a thickened edge portion (bead) that cannot be used commercially. According to embodiments disclosed herein, a flow member is disclosed and is generated by the flow member when the flow member is inserted into the edge of the glass ribbon such that the glass ribbon flows over the flow member. The bead becomes thinner and more glass can be used, thereby increasing manufacturing efficiency and further reducing the amount of noble metal (eg, platinum) utilized in the manufacturing process.

  In one aspect, a method for changing the flow of molten glass is described, the method comprising flowing molten glass from a molded body as a molten glass ribbon and a molten glass ribbon on a flow member spaced from the molded body. The flow member extending a predetermined distance into the molten glass ribbon such that the molten glass ribbon flows over the flow member.

  The step of flowing the molten glass from the molded body may include the step of flowing the molten glass from the lower edge of the molded body where the merged molding surfaces of the molded body meet.

  In some embodiments, the flow member may be movable in the vertical direction. In some embodiments, the flow member may be horizontally movable. In some embodiments, the flow member may be movable vertically and horizontally.

  The flow member may have a plate-like structure and includes first and second main surfaces, and the molten glass ribbon flows on the first and second main surfaces, and the first and second The main surfaces may be parallel to each other.

  In some embodiments, the flow member may have a plate-like structure and may include first and second major surfaces, the molten glass ribbon flowing over the first and second major surfaces, Furthermore, the first and second main surfaces of the flow member are parallel to a vertical plane passing through the lower edge of the molded body.

  In some embodiments, the flow member comprises first and second major surfaces, the molten glass ribbon flows over the first and second major surfaces, and the molten glass ribbon comprises the first and second major surfaces. It flows over the entire surface area of the main surface.

  The flow member can be positioned between the uppermost edge roll and the lower edge of the molded body.

  In some embodiments, the flow member may be heated, for example, by establishing a current in a heating element positioned on or in the flow member.

  In some embodiments, the flow member is substantially immersed in the glass ribbon, such as when the flow member is configured as a wire or rod, or an elongated flat strip.

  In some embodiments, the surface area of the flow member wetted by molten glass may be varied.

  In some embodiments, the distance between the uppermost edge of the flow member wetted by the molten glass ribbon and the lower edge of the molded body may be varied.

  The method may further include the step of overlapping the molten glass ribbon with the plurality of flow members, each flow member of the plurality of flow members such that at least a portion of the entire surface area of the flow member is wetted with the molten glass. Extends a predetermined distance from the edge into the molten glass ribbon.

  In another aspect, an apparatus for stretching a molten glass ribbon is described, the apparatus being a molded body, wherein the molten glass ribbon is stretched from the molded body, and spaced apart from the molded body. A flow control device having a flow member positioned directly below the body, the flow member having an opposing planar surface, and the flow member in a vertical plane passing through the lower edge of the molded body Are spaced apart from the molded body, and extend through the molded body and longitudinally of the molded body so that the molten glass ribbon from the molded body can flow over the main surface of the flow member. The flow member is positioned at a predetermined distance L from the vertical plane perpendicular to the axis. At this time, L is measured from the tip of the flow member to the vertical plane.

  The flow control device may further comprise a positioning device configured to change the distance L. The flow control device may be configured to move the flow member vertically, horizontally, or both vertically and horizontally.

  The apparatus for drawing the molten glass ribbon may further include a plurality of flow control devices, and each flow control device of the plurality of flow control devices includes a flow member.

  In yet another aspect, a method for changing the flow of molten glass is disclosed, the method comprising flowing molten glass from a molded body as a molten glass ribbon, spaced from the lower edge of the molded body, A step of superimposing a molten glass ribbon on a flow member having first and second main surfaces, wherein the molten glass is stretched from the lower edge of the molded body, and the molten glass ribbon further extends over the flow member. The flow member extending a predetermined distance into the molten glass ribbon to flow.

  Additional features and advantages of the embodiments disclosed herein will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art from that description, or may be apparent from the following detailed description, claims. Will be appreciated by implementing the embodiments described herein, including the section, as well as the attached drawings.

  It should be understood that the foregoing general description and the following detailed description are exemplary of the present disclosure and are intended to provide an overview or configuration for understanding the embodiments. The accompanying drawings are included to provide a further understanding of the embodiments, and are incorporated in and constitute a part of this specification. The drawings illustrate various embodiments of the disclosure, and together with the description, serve to explain the principles and operations of the embodiments.

Front view of an example of a glass manufacturing apparatus according to an embodiment of the present disclosure FIG. 3 is a cross-sectional view of a glass ribbon formed by a downdraw process, showing a bead (edge portion) and a quality region of the ribbon. The perspective view which showed the fusion-type shaping | molding main body provided with the conventional edge guide member The perspective view which showed the fusion-type shaping | molding main body provided with the conventional edge guide member 1 is a cross-sectional end view of the molded body of FIG. 1 showing a flow member immersed in a flowing molten glass ribbon, according to embodiments disclosed herein. 1 is a perspective view of a flow control device comprising a generally rectangular flow member according to an embodiment of the present disclosure. Front view of a flow control device according to another embodiment of the present disclosure comprising a triangular flow member Schematic illustration of various flow member shapes according to embodiments disclosed herein. Schematic illustration of various flow member shapes according to embodiments disclosed herein. Schematic illustration of various flow member shapes according to embodiments disclosed herein. Sectional end view of a flow member according to embodiments disclosed herein, comprising at least one major curved surface Sectional end view of a flow member according to embodiments disclosed herein, comprising at least one major curved surface Front view of a flow control device according to another embodiment of the present disclosure comprising an elongated strip flow member. Front view of a flow control device according to another embodiment of the present disclosure comprising a rod-like or wire flow member FIG. 6 shows a performance comparison between a conventional edge guide member (right side) and an embodiment (left side) of a flow member according to an embodiment of the present disclosure that is fully immersed in the edge flow of a molten glass ribbon; Experimental setup photo FIG. 6 shows a performance comparison between a conventional edge guide member (right side) and a flow member (left side) according to another embodiment of the present disclosure that extends only partially into the edge flow of a molten glass ribbon. , Another experimental setup photo FIG. 2 is a cross-sectional view of a glass ribbon formed by the example of the downdraw process of FIG. 1, wherein the two beads forming the ribbon are not completely joined together (a thickened edge). Part) FIG. 2 is a cross-sectional view of a glass ribbon formed by the example of the downdraw process of FIG. 1, showing a formed air line;

  Reference will now be made in detail to various embodiments of the disclosure, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. The flow control device embodiments described herein can be used in a variety of downdraw glass manufacturing processes such as, but not limited to, slot draw and fusion processes, but the following embodiments are associated with the fusion process. I will explain.

  FIG. 1 is a side view of an example glass forming apparatus 10 according to the present disclosure, which includes a dissolution vessel 12, a clarification vessel 14, a stirring vessel 16, a delivery vessel 18, and a delivery vessel outlet conduit 20. . The dissolution tank 12 is coupled to the clarification tank 14 via a dissolution tank-clarification tank connection pipe 22, and the clarification tank 14 is coupled to the mixing tank 16 via a clarification tank-stirring tank connection pipe 24. A glass raw material, hereinafter “batch”, is fed to the melting bath 12 as indicated by arrow 26 and further heated to a first temperature T 1 to produce a viscous molten material, hereinafter molten glass 28. By way of example, but not limitation, T1 for glass compositions suitable for display panel manufacture, such as aluminoborosilicate glass, can be in the range of about 1500 ° C. to about 1600 ° C.

  The molten glass 28 flows to the clarification tank 14 through the dissolution tank-clarification tank connection pipe 22. The molten glass 28 is heated in the clarification tank 14 to a second temperature T2 higher than the melting temperature T1 in the melting tank 12, thereby further reducing the viscosity of the molten glass. By way of example, and not limitation, T2 for a glass composition suitable for display panel manufacture can be a temperature in the range of about 1600 ° C. to about 1700 ° C. The decrease in the viscosity of the molten glass 28 as the temperature increases from T1 to T2 helps bubbles in the molten glass rise to the free surface of the molten glass in the fining vessel 14. Furthermore, generally called a fining agent, for example, a polyvalent compound contained in a molten glass represented by an oxide of tin (Sn), cerium (Ce), arsenic (As), and / or antimony (Sb), It decreases chemically at the clarification tank temperature T2, thereby releasing oxygen as bubbles in the molten glass. These bubbles rise through the low viscosity molten glass in the fining tank 14 to the free surface 30 of the molten glass and collect other gases generated during the melting process as the bubbles rise. At the free surface 30, the gas containing bubbles is released and released from the fining tank.

  The molten glass flows from the fining vessel 14 to a mixing vessel 16 where it is mechanically mixed to homogenize the molten glass. For example, the mixing tank 16 may be a stirring tank, and the stirring tank may be provided with a stirrer 32 that is rotatably installed in the stirring tank and stirs the molten glass in the stirring tank. However, in other embodiments, the mixing vessel 16 may be a static mixing vessel with stationary blades configured to change the flow of molten glass. Molten glass flows from the mixing vessel 16 to the delivery vessel 18 through the mixing vessel-delivery vessel connection pipe 34. The molten glass is further cooled to the molding temperature or a temperature in the vicinity thereof while passing to the delivery tank 18. The direction of the molten glass flow changes within the delivery tank 18, for example, from a substantially horizontal flow to a substantially vertical flow, and the molten glass is subsequently injected into the forming body 38 via the outlet conduit 20. It is delivered to the inlet conduit 36.

  The molded body 38 may include a merged molding surface 40 on the outside of the molded body 38 that merges along the lower edge 42 of the molded body. The molded body 38 may further comprise a trough 44 that is positioned on the upper surface of the molded body and is fed with molten glass 28 from the inlet conduit 36. Molten glass flows from the inlet conduit 36 into the trough 44 and overflows from the trough walls. The overflowing molten glass flows as a separated flow of the molten glass on the confluence forming surface 40, and this molten glass is combined at the lower edge 42 to become a molten glass ribbon 46. The molten glass ribbon 46 is appropriately positioned with respect to gravity. The film is drawn downward in the drawing direction 48 by a combination with a roll such as an edge roll and / or a pull roll.

  When the molten glass ribbon 46 descends downward, a phenomenon called a reduction in the width of the ribbon, hereinafter referred to as attenuation, occurs due to surface tension while the molten glass ribbon is still in a formable viscosity. Due to the damping, the thickness of the edge portion 50 (see FIG. 2) of the molten glass ribbon is increased compared to the central region of the ribbon. This edge portion 50 of increased thickness is known as a bead. The usable area of the glass ribbon is a central area having a generally uniform thickness of the glass ribbon between the beads, as shown in the cross-sectional view of the glass ribbon 46 in the example of FIG. It is. Typically, the thickness of the high quality area when the ribbon reaches the final thickness is about 2 millimeters or less, such as about 1 millimeter or less, or about 0.7 millimeters or less. In some embodiments, the thickness of the high quality area after the ribbon has reached the final thickness ranges from about 0.1 millimeters to about 0.7 millimeters. In still other embodiments, the final thickness of the high quality area may range from about 0.01 millimeters to about 0.1 millimeters. As explained, the edge portion 50 shows a deviation from the desired ribbon thickness. In addition, for example, in ultra-thin glass ribbons where the thickness of the high quality area is approximately 0.1 mm or less, the thickened edge portions are produced when the glass ribbon is rolled onto a receiving spool, for example in a winding process. It can be an obstacle. Therefore, the thickened edge portion can be removed. In some processes, the thickened edge portions are removed from individual glass sheets cut from the glass ribbon. In other processes, the thickened edge portion can be removed directly from the ribbon during the drawing process. In any event, at least attenuated and used commercially because the total width of the molten glass ribbon is reduced and the edge portion 50 of the molten glass ribbon is thicker than the high quality area 52 and must eventually be removed. The possible glass ribbon 46 width is reduced.

  Returning to FIG. 1, the molten glass ribbon is drawn from the lower edge 42 of the forming body 38 by the influence of gravity and, for example, a pair of opposing traction rolls 54 that rotate counterclockwise. Opposing rolls of a pair of traction rolls are positioned to grip the thickened edge portion 50 and apply a downward traction force to the molten glass ribbon 46. Other rolls, commonly referred to as edge rolls 56, may be positioned above and / or below the pull rolls to assist in the stretching process. The edge roll applies a downward traction force to the molten glass ribbon, but further weakens the inward shrinkage of the glass ribbon, thereby minimizing the shrinkage of the glass ribbon in the direction perpendicular to the stretching direction. Similar to the pull roll, the edge roll 56 is also placed in an opposing relationship when engaging the edge portion of the glass ribbon. The edge roll 56 may be driven or not driven depending on its position and specific function. The rotation axis of the edge roll 56 may be horizontal with respect to the horizontal reference plane, or may be inclined. However, how close the top edge roll 56 can be positioned to the lower edge 42 of the molded body 38 is used to control the temperature and viscosity of the molten glass ribbon and thereby the thickness. There are limitations due to the arrangement of at least other equipment, such as heating and cooling equipment. Thus, immediately below the lower edge 42 of the molded body 38, above the uppermost edge roll 56, there is a region of molten glass ribbon that is not in contact with either the edge roll or the traction roll and therefore is subject to damping. Can do.

  In the prior art method of increasing the ribbon width, the web surface extending between the downward confluence forming surface 40 of the forming body 38 and the protruding edge or dam 60, as shown in FIG. 3A. 58 ("edge guide member") was employed. For example, the web surface disclosed in U.S. Pat. No. 3,451,798 is at its lowest level at the level of a horizontal plane passing through the lower edge of the molded body, which is the line where the downwardly merged molding surfaces of the molded body meet. The range ends. U.S. Pat. No. 3,537,834 is disclosed in U.S. Pat. No. 3,451,798, the lowest point of which can extend below the lower edge of the molded body. A forming device with a similar web surface is disclosed. This edge guiding member 58 is shown in FIG. 3B. U.S. Pat. No. 7,409,839 includes at least two planar surfaces positioned at an angle to each other and has the lowest point as disclosed in U.S. Pat. No. 3,537,834. Yet another edge guide member is disclosed that may extend below the lower edge of the molded body.

  Although the aforementioned edge guides are effective in reducing or preventing lateral attenuation of the molten glass ribbon, the bead is said to occur normally when such edge guides are not present. It tends to be bigger than it would be. Furthermore, the edge guide member uses a significant amount of platinum in its structure, thus representing a considerable cost. As mentioned above, the beads are undesirable because they exhibit a local increase in the thickness of the glass ribbon and must be removed prior to sale of the glass sheet cut from the ribbon. Thus, the beads are wasted for the manufacturing process and represent an undesirable cost. Thus, the use of edge guides described in the prior art involves tradeoffs that increase ribbon width at the expense of increased bead size and capital costs.

  During normal use, the prior art edge guides described above typically provide a net increase in the area of usable ribbon. That is, increasing the overall ribbon width tends to increase the high quality area of the ribbon further than increasing the bead size, which reduces the high quality area of the ribbon, resulting in a net increase in ribbon width. However, there is always a need to reduce manufacturing costs and further innovation is required to increase the usable area of the ribbon. Therefore, even when the glass ribbon is stretched from the lower edge that remains the molded body (that is, the above-mentioned prior art edge guide member does not exist), when the conventional edge guide member is adopted Thus, an apparatus that can effectively increase the ribbon width obtained while reducing the thickened edge portion will be described herein.

  1 and 4-6, the flow control device 62 is positioned below the lower edge 42 of the forming body 38 and above the uppermost set of edge rolls 56. The flow control device 62 is positioned below the lower edge 42 of the forming body 38 and spaced from the lower edge 42 (separated from the lower edge 42) above the uppermost set of edge rolls 56, A flow member 64 is provided. A single flow controller is described with the understanding that a plurality of flow controllers 62 may exist, but a second similar or identical flow controller 62 may be employed. For example, a similar or identical second flow control device 62 may be positioned on the opposite lateral side of the first flow control device. In other embodiments, multiple flow control devices 62 may be positioned vertically spaced along the edges of the glass ribbon.

  As shown in FIG. 1, the flow member 64 is positioned proximate to the first end 66 of the molded body 38 below the lower edge 42 and spaced from the lower edge 42 (second The second flow member 64 constituting the flow control device 62 may be positioned close to the second end 67 of the molded body 38, spaced below the lower edge 42 and spaced from the lower edge 42). The uppermost edge 68 of each flow member 64 may be positioned, for example, at a distance of at least 1 cm below the lower edge 42 of the molded body 38, such as in the range of about 1 cm to about 5 cm. Therefore, the flow member 64 is not in contact with the molded body 38. Because the flow member 64 and the molded body 38 are not connected, the flow member and / or flow control device 62 is easier to replace than when the flow member is attached to the molded body. According to this embodiment, the flow member 64 includes first and second main surfaces, that is, a first main surface 70 and a second main surface 72. As shown in FIG. 5, the exemplary flow control device 62 includes a flow member 64 that includes the first major surface 70 and the second major surface 72 described above. The first main surface 70 and the second main surface 72 may be planar, for example, or may be parallel so that the flow member 64 has a plate-like configuration. Further, the first main surface 70 and the second main surface 72 may be parallel to a vertical plane 74 passing through the lower edge 42 (see FIG. 4). The flow member shown in FIG. 5 is generally rectangular in shape. An alternative embodiment where the flow member is generally triangular in shape is shown in FIG. In still other embodiments, the flow member 64 can include one or more curved edges. Note further that the major surfaces 70, 72 need not be planar or parallel. For example, the main surfaces 70 and 72 may be curved. For example, FIGS. 7A and 7B show an alternative embodiment of the flow member 64 with a curved edge 69. FIG. 7C shows another embodiment of a triangular shaped member configured as a right triangle. FIGS. 8A and 8B illustrate yet another flow member 64 embodiment comprising at least one curved major surface 70 and / or 72.

  In yet another example, shown in FIGS. 9 and 10, each flow member 64 may be formed as an elongated strip (FIG. 9) that extends generally in the longitudinal direction of the ribbon, or molten glass. Formed as a rod or wire type flow member 64 (FIG. 10) that is immersed in the bead region of the ribbon 46, again extending generally in the longitudinal direction of the ribbon (eg, along the stretch direction 48). May be. Since the transverse edge of the molten glass ribbon flowing over the rod or wire generally follows the contour of the rod or wire, the rod or wire may be bent to follow the desired contour shape of the transverse edge of the ribbon. In addition, this wire-like flow member minimizes the material used, and thus costs are minimized (because of the harsh environment caused by molten glass, the flow member according to the present disclosure is, for example, platinum or platinum rhodium alloy). Note that it may be constructed from a material similar to the edge guide member, such as a platinum alloy).

  The flow member 64 is shaped so that the molten glass ribbon edge portion (bead) 50 flows around at least a portion of the flow member before the molten glass reaches the first set of edge rolls 56. It is configured to overlap the free flow of glass from the lower edge 42 of the glass. That is, the flow member 64 not only contacts the glass flow, but also extends into the flow of the molten glass ribbon 46 so that the molten glass flows over at least a portion of both major surfaces 70, 72 of the flow member 64. doing. Note that the flow of molten glass does not necessarily cover the entire major surface of the flow member. Thus, a portion of the main surface of the flow member can remain wet with the molten glass. For example, in FIG. 5, the shaded portion of the first major surface 70 (and the second major surface 72 not shown) is the surface area of the flow member 64 that can be wetted with molten glass in certain embodiments. This part is drawn.

  The flow control device 62 may include a mounting arm 76 to which the flow member 64 is coupled, or the mounting arm 76 may be an integral part of the flow member 64. A mounting arm 76 can be used to couple the flow member 64 to a respective mounting device 78 that is configured to install and position the flow member in the molten glass stream (molten glass ribbon 46). In some embodiments, the mounting arm may not be required because the flow member may be directly coupled to the mounting device.

The flow member 64 is formed from a rigid material compatible with molten glass that is not easily deformed by the flow of molten glass in contact with the flow member. This conformation means that the material constituting the flow member does not easily dissolve in the molten glass, or does not cause fine particles to fall into the molten glass, and does not significantly deteriorate the material. Or it means that it can expose to the high temperature of a molten glass over a long period, without changing a shape. The temperature of the molten glass of the molten glass ribbon to which the flow member 64 can be exposed is, for example, a temperature of about 700 ° C. or higher, 800 ° C. or higher, or even 900 ° C. or higher, for example, a temperature in the range of about 700 ° C. to about 1200 ° C. But you can. As described above, each flow member 64 may include platinum or a platinum alloy such as a platinum rhodium alloy or a platinum iridium alloy. Alternative materials may include ZrSiO ₄ , or Haynes® alloy. Suitable materials can include materials that dissolve over time, but this dissolved material becomes a non-hazardous part of the overall molten glass composition that does not materially affect the performance of the resulting glass article. . In some embodiments, each flow member 64 can comprise a suitable silicate glass or non-silicate glass, or can comprise a suitable ceramic material.

  The mounting device 78 may include a positioning device 80 for adjusting the position of the flow member 64, which adjustment is made on a vertical plane 84 extending through the forming body, perpendicular to the longitudinal axis of the forming body ( That is, flow in a direction 82 toward or away from the molten glass ribbon, and thus in a direction 82 that increases or decreases the surface area of the flow member wetted by the molten glass, or in a vertical direction 86 toward or away from the lower edge 42 of the molded body 38. This can be done by moving the member. The vertical plane 84 may correspond to the center line of the molten glass ribbon.

  Using the positioning device 80 for a flow member 64 that maximizes the width of the molten glass ribbon while minimizing the bead size (thickness and / or width) of the molten glass ribbon for a particular design of the flow member. An optimal position can be obtained. In certain embodiments, the installation device may be configured to provide rotational motion to the flow member 64, thereby causing a change in the angle of attack of the flow member relative to the flow of molten glass. In some embodiments, each installation device 78 may be substantially fixed or configured so that the flow member 64 is not easily positioned. For example, each installation device 78 may be rigidly coupled to a structural member (not shown), such as a structural steel beam that supports or includes one or more other components of the stretching device. . In such an embodiment, when repositioning the flow member 64, it may be necessary to separate the installation device 78 from the structural member and reconnect it to another location.

  FIGS. 11 and 12 are photographs showing experiments performed with a simulated molded body configured to mimic the operation of the industrial molded body described above. Simulate the flow of molten glass on and from the molded body using a petroleum product (oil or wax) that has a viscosity substantially equal to the viscosity of the molten glass flowing over the molded body in the actual glass manufacturing process To do. The exact viscosity depends on the glass composition to be mimicked. The use of simulated molten glass, such as paraffin, can be beneficial in that the experiment can be performed at room temperature, or at least at a temperature at which the performance of the analyzed flow member can be easily observed. Positioned on the right side of FIGS. 11 and 12 (when viewed on the page of the drawing) is the extension between the confluent molding surface of the molded body and the dam portion located at the right end of the molded body. This is a conventional edge guiding member. Positioned on the left is a flow member 64 as described above, which is completely immersed in the molten glass flow coming from the forming body. The particular flow member shown in FIG. 11 is of a triangular design with a downward apex. That is, the upper edge of the triangle is substantially horizontal, while the two additional side edges meet in the direction of stretching. The dotted line 90 and the alternate long and short dash line 92 indicate the relative positions of the lower edge 42 of the molded body 38 and the upper edge of the flow member 64, respectively. As shown in FIG. 11, the flow of simulated molten glass in the flow member (left side of the figure) is shown on the right side of the figure (as represented by the size of the right and left bead). It is generally the same as the flow of molten glass from a conventional edge guide member, and the flow member of FIG. 11 reduces the amount of material (eg, the same platinum or platinum alloy used in conventional edge guide members). However, it shows that it is at least as effective as the conventional edge guide member. In contrast to FIG. 11, FIG. 12 shows that the flow member 64 on the left side of the drawing is not completely immersed in the molten glass flow, and only a part of its main surface is wet with the molten glass. The setup is the same as in FIG. In the embodiment of FIG. 12, the ribbon is attenuated more rapidly on the side of the flow member of the molten glass flow (left side) than the molten glass flow on the conventional edge guiding member (right side). The size (e.g., width and / or thickness) is significantly reduced. 11 and 12 therefore position the flow member inwardly toward the centerline of the molten glass ribbon or outwardly away from the centerline of the molten glass ribbon to optimize the size of the high quality area. This clearly demonstrates that the width profile of the molten glass ribbon and the size (eg, thickness) of the edge portion can be manipulated. The optimal positioning of the flow member to maximize the width of the high quality area and to minimize the bead thickness and width are, among other things, the shape of the flow member, the flow rate of the molten glass, and the molten glass. Depends on temperature (viscosity).

  Modeling has shown more generally that changing the surface area of a flow member wetted by molten glass changes the velocity of the molten glass flowing over the main surface of the flow member. As the velocity of the molten glass flowing over the surface of the flow member decreases, the attenuation also decreases. It has also been found that a narrower flow member in the generally vertical direction produces less noticeable (smaller) edge portions. Thus, long and narrow flow members, such as the flow members of FIGS. 9 and 10, minimize the size of the thickened edge portion than wide (in the direction of flow) short flow members (in the direction perpendicular to the direction of flow). However, it may be more effective to maximize the width of the high quality area.

  In some embodiments, one or more heating elements 93 (see FIG. 5) may be positioned on and / or in the flow member 64. A heating element can be used to locally control the temperature and thus the viscosity of the molten glass flowing over the flow member. Heating of the flow member 64 can be used continuously or intermittently to prevent devitrification of the glass, for example when the glass is stretched below its liquidus temperature. In practice, using the flow member according to the embodiments described herein, the glass ribbon can be used to intentionally stretch at a temperature below the liquidus temperature of the glass. Alternatively, when accumulation of devitrification occurs in the flow member, devitrification can be removed by heating. The heating element may be of the resistance type, where an electric current is established by the heating element 93 and Joule heating occurs. Alternatively, other methods of heating the flow member known in the art, such as by microwaves, can be used.

  In addition to reducing the size of the thickened edge portion and reducing attenuation, the flow member according to embodiments of the present disclosure can help strengthen the bond of the separated glass streams. FIG. 13 shows the edge portion 50 because the flow of one molten glass from the forming body (the flow coming from one merged forming surface of the forming body 38) was not well coupled to the flow of the opposite molten glass. The figure shows an example of a thickened edge portion 50 in which a dent or dimple 94 is formed. In some cases, as shown in FIG. 14, this dimple may provide an air line 96. Such edge anomalies, and particularly air lines, can disrupt the cutting process, for example, by causing the cutting line to deviate from its intended path when a separate glass sheet is cut from the glass ribbon. Alternatively, such an edge abnormality may cause a stress on the ribbon edge that adversely affects the shape of the center portion (high quality area) of the ribbon or the shape of the glass sheet to be cut. In yet other instances, the presence of an air line can cause an uncontrolled crack in the ribbon. Modeling has shown that the flow member embodiments described herein can reduce the formation of these dimples and / or air lines.

  It will be apparent to those skilled in the art that various modifications and variations can be made to the embodiments of the present disclosure without departing from the spirit or scope of the disclosure. Thus, if such modifications and variations are within the scope of the appended claims and their equivalents, the present disclosure is intended to include these modifications and variations.

  Hereinafter, preferable embodiments of the present invention will be described in terms of items.

Embodiment 1
In a method of changing the flow of molten glass,
Flowing the molten glass from the molded body as a molten glass ribbon; and
A step of superimposing the molten glass ribbon on a flow member spaced from the forming body, wherein the flow member is immersed in at least a part of the flow member in the molten glass ribbon; Extending a predetermined distance into the edge of the molten glass ribbon,
A method comprising the steps of:

Embodiment 2
The method according to claim 1, wherein the step of flowing the molten glass from the molded body includes the step of flowing the molten glass from a lower edge of the molded body where the merged molding surfaces of the molded body merge.

Embodiment 3
The flow member includes first and second main surfaces opposed to each other, the molten glass flows on the first and second main surfaces, and the first and second main surfaces of the flow member are The method of embodiment 2, wherein the method is parallel to a vertical plane passing through the lower edge of the molded body.

Embodiment 4
The method of embodiment 2, wherein the flow member is positioned between an uppermost edge roll and the lower edge of the molded body.

Embodiment 5
3. The method of embodiment 2, further comprising changing a distance between an uppermost edge of the flow member wetted by the molten glass ribbon and the lower edge of the molded body.

Embodiment 6
The method of embodiment 1, further comprising moving the flow member in a vertical direction.

Embodiment 7
The method of embodiment 1, further comprising moving the flow member in a horizontal direction.

Embodiment 8
The flow member includes first and second main surfaces facing each other, the molten glass flows on the first and second main surfaces, and the first and second main surfaces are parallel to each other. Embodiment 2. The method of embodiment 1 characterized by the above-mentioned.

Embodiment 9
The flow member includes first and second main surfaces facing each other, the molten glass flows on the first and second main surfaces, and the molten glass further includes the first and second main surfaces. Embodiment 2. The method of embodiment 1 wherein the entire surface area is contacted.

Embodiment 10
2. The method of embodiment 1, further comprising heating the flow member with a heating element positioned on or within the flow member.

Embodiment 11
The method of embodiment 1, wherein the flow member is completely immersed in the molten glass ribbon.

Embodiment 12
The method of embodiment 1, further comprising the step of changing a surface area of the flow member wetted by the molten glass.

Embodiment 13
The step of overlapping the molten glass ribbon further comprises overlapping the molten glass ribbon to a plurality of flow members, each flow member of the plurality of flow members extending a predetermined distance into the molten glass ribbon. Embodiment 2. The method of embodiment 1 characterized in that:

Embodiment 14
In an apparatus for drawing a molten glass ribbon,
A molded body, from which the molten glass ribbon is stretched, and a molded body;
A flow control device comprising a flow member positioned directly below the molding body at a distance from the molding body;
The flow member has an opposing planar surface, and the flow member is disposed in a vertical plane passing through the lower edge of the molded body and spaced from the molded body, In addition, the molten glass from the molded body is perpendicular to the longitudinal axis of the molded body and allows the lower edge of the molded body to be moved in two directions so that the molten glass can flow on the opposing planar surface of the flow member. The flow member is positioned at a predetermined distance L from the equally divided vertical plane, where L is measured from the vertical plane to the end of the flow member closest to the vertical plane. A device characterized by being.

Embodiment 15
The apparatus of embodiment 14, wherein the flow control device further comprises a positioning device coupled to the flow member and configured to vary the distance L.

Embodiment 16
The apparatus of embodiment 14, wherein the flow control device is configured to move the flow member in a vertical direction.

Embodiment 17
The apparatus of embodiment 14, wherein the flow control device is configured to move the flow member in a horizontal direction.

Embodiment 18
15. The apparatus of embodiment 14, further comprising a plurality of flow control devices, wherein each flow control device of the plurality of flow control devices comprises a flow member.

Embodiment 19
Embodiment 15. The apparatus of embodiment 14, wherein the flow member has a triangular shape.

Embodiment 20.
In a method of changing the flow of molten glass,
Flowing the molten glass from the molded body as a molten glass ribbon; and
Overlaying the molten glass on a flow member having first and second main surfaces, spaced from the lower edge of the molded body, wherein the molten glass ribbon is the molded body The flow member extends a predetermined distance into the molten glass such that the molten glass flows over the first and second major surfaces of the flow member. Step,
A method comprising the steps of:

38 Molding body 42 Lower edge 46 Molten glass ribbon 62 Flow control device 64 Flow member 70 First main surface 72 Second main surface 74, 84 Vertical plane

Claims (10)

In a method of changing the flow of molten glass,
Flowing the molten glass from the molded body as a molten glass ribbon; and
A step of superimposing the molten glass ribbon on a flow member spaced from the forming body, wherein the flow member is immersed in at least a part of the flow member in the molten glass ribbon; Extending a predetermined distance into the edge of the molten glass ribbon,
A method comprising the steps of:   The method of claim 1, wherein the step of flowing the molten glass from the molded body includes the step of flowing the molten glass from a lower edge of the molded body where the merged forming surfaces of the molded body merge.   The flow member includes first and second main surfaces opposed to each other, the molten glass flows on the first and second main surfaces, and the first and second main surfaces of the flow member are 3. The method of claim 2, wherein the method is parallel to a vertical plane passing through the lower edge of the molded body.   The method of claim 2, wherein the flow member is positioned between an uppermost edge roll and the lower edge of the molded body.   The method of claim 2, further comprising changing a distance between an uppermost edge of the flow member wetted by the molten glass ribbon and the lower edge of the molded body.   6. A method according to any preceding claim, further comprising moving the flow member in a horizontal direction.   The method of any one of claims 1 to 6, further comprising heating the flow member with a heating element positioned on or in the flow member. In an apparatus for drawing a molten glass ribbon,
A molded body, from which the molten glass ribbon is stretched, and a molded body;
A flow control device comprising a flow member positioned directly below the molding body at a distance from the molding body;
The flow member has an opposing planar surface, and the flow member is disposed in a vertical plane passing through the lower edge of the molded body and spaced from the molded body, Further, the flow member is positioned at a predetermined distance L from the center line of the molded body so that the molten glass from the molded body can flow on the opposing planar surface of the flow member. In this case, the apparatus is characterized in that L is measured from the tip of the flow member to a vertical plane perpendicular to the longitudinal axis of the molded body.   9. The flow control device of claim 8, further comprising a positioning device coupled to the flow member and configured to change the distance L by moving the flow member. apparatus. In a method of changing the flow of molten glass,
Flowing the molten glass from the molded body as a molten glass ribbon; and
A step of superimposing the molten glass ribbon on a flow member having first and second main surfaces disposed at a distance from a lower edge of the molded body, the molten glass comprising the molded body; Extending from the lower edge of the flow member, and the flow member extending a predetermined distance into the molten glass ribbon such that the molten glass ribbon flows over the flow member;
A method comprising the steps of:

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