Patent Publication Number: US-2021163332-A1

Title: Methods and apparatus for forming laminated glass sheets

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of priority of U.S. Provisional Application Ser. No. 62/717,173 filed on Aug. 10, 2018 and U.S. Provisional Application Ser. No. 62/876,090 filed on Jul. 19, 2019, the contents of which are relied upon and incorporated herein by reference in their entirety as if fully set forth below. 
    
    
     BACKGROUND 
     Field 
     The present specification generally relates to methods and apparatuses for forming glass sheets and, more specifically, to forming bodies and methods for forming continuous laminate glass ribbons having a plurality of glass layers. 
     Technical Background 
     The fusion process is one technique for forming continuous glass ribbons. Compared to other processes for forming glass ribbons, such as the float and slot-draw processes, the fusion process produces glass ribbons with a relatively low amount of defects and with surfaces having superior flatness. As a result, the fusion process is widely employed for the production of glass substrates used in the manufacture of LED and LCD displays and other substrates that require superior flatness. In the fusion process molten glass is fed into a forming body (also referred to as an isopipe), which includes forming surfaces that converge at a root. The molten glass evenly flows over the forming surfaces of the forming body and forms a ribbon of flat glass with pristine surfaces that is drawn from the root of the forming body. 
     Laminating a plurality of different glass compositions together to produce laminate glass sheets can provide different properties to glass sheets, such as improved strength or various optical properties. Laminate glass sheets have been made by a fusion process using a double overflow isopipe, which includes two or more overflow isopipes arranged in a vertical relationship, each overflow isopipe having two weirs over which the molten glass overflows. However, some double overflow isopipe designs may limit the glass compositions that can be incorporated into the laminate glass sheets or have other challenges overcome by technology disclosed herein. 
     Accordingly, a need exists for alternative apparatuses and methods for producing continuous laminate glass ribbons using fusion process technology. 
     SUMMARY 
     In a first aspect of the present disclosure, a forming body of a glass forming apparatus is disclosed that may comprise a first conduit comprising a first conduit wall having an interior surface defining a first region and at least one slot extending through the first conduit wall and in fluid communication with the first region. The at least one slot of the first conduit may have a longest dimension aligned with a direction of flow through the first conduit. The forming body may further include a second conduit disposed above and vertically aligned with the first conduit, the second conduit comprising a second conduit wall having an interior surface defining a second region and at least one slot extending through the second conduit wall and in fluid communication with the second region. The at least one slot of the second conduit may have a longest dimension aligned with a direction of flow through the second conduit. The forming body may further include a first vertical wall extending between an outer surface of the second conduit wall and an outer surface of the first conduit wall at a first side of the forming body and a second vertical wall extending between the outer surface of the second conduit wall and the outer surface of the first conduit wall at a second side of the forming body. The forming body may further include a first forming surface and a second forming surface extending from an outer surface of the first conduit wall. The first forming surface and the second forming surface may converge at a root of the forming body. 
     A second aspect of the present disclosure may include the first aspect, wherein the first conduit may comprise a first slot extending through the first conduit wall proximate the first side of the forming body and a second slot extending through the second conduit wall proximate the second side of the forming body opposite the first side of the forming body. 
     A third aspect of the present disclosure may include either the first or the second aspect, wherein the at least one slot of the second conduit may extend through the second conduit wall at an uppermost portion of the second conduit wall so that molten glass flowing through the at least one slot in the second conduit wall flows down the first side and the second side of the forming body. 
     A fourth aspect of the present disclosure may include either the first or the second aspect, wherein the second conduit may include a first slot extending through the second conduit wall at the first side of the forming body and a second slot extending through the second conduit wall at the second side of the forming body. 
     A fifth aspect of the present disclosure may include the first aspect, wherein the first conduit may include a single slot disposed on the first side of the forming body, and the second conduit may include a single slot disposed on the second side of the forming body opposite the first side. 
     A sixth aspect of the present disclosure may include any of the first through fifth aspects, wherein the first vertical wall, the second vertical wall, or both, may be configured so that a second molten glass flow from the second conduit maintains contact with the forming body until it contacts a first molten glass flow from the first conduit. 
     A seventh aspect of the present disclosure may include any of the first through sixth aspects, wherein the first vertical wall, the second vertical wall, or both may be configured so that a second molten glass flow from the second conduit does not free fall over a distance between the second conduit and the first conduit. 
     An eighth aspect of the present disclosure may include any of the first through seventh aspects, wherein the first vertical wall outer surface may be spaced horizontally outward relative to the outer surface of the first conduit wall proximate the at least one slot in the first conduit wall so that the first vertical wall outer surface is vertically offset from the outer surface of the first conduit wall. 
     A ninth aspect of the present disclosure may include the eighth aspects, wherein the vertical offset may be configured so that deformation of a second molten glass flow from the second conduit is reduced at a confluence of the second molten glass flow with a first molten glass flow from the first conduit. 
     A tenth aspect of the present disclosure may include either ofthe eighth or ninth aspects, wherein the vertical offset may be less than or equal to a thickness of a core layer of a laminated glass sheet formed with the forming body. 
     An eleventh aspect of the present disclosure may include any one of the first through tenth aspects, wherein each of the at least one slot in the first conduit wall, each of the at least one slot in the second conduit wall, or combinations thereof, may include a plurality of slots. Each of the plurality of slots may be aligned along a linear path parallel to the flow direction of the first conduit or the second conduit, respectively. 
     A twelfth aspect of the present disclosure may include any one of the first through eleventh aspects, wherein the forming body may further comprise at least one supplemental conduit disposed above and vertically aligned with the first conduit and the second conduit. The at least one supplemental conduit may have a supplemental conduit wall having an interior surface defining a supplemental region and at least one slot extending through the supplemental conduit wall. The at least one slot of the supplemental conduit may have a longest dimension aligned with a direction of flow through the supplemental conduit. The forming body may further include a plurality of supplemental vertical walls extending between the outer surface of the second conduit and an outer surface of the at least one supplemental conduit. 
     A thirteenth aspect of the present disclosure may include the twelfth aspect, comprising a plurality of supplemental conduits and a plurality of supplemental vertical walls, each of which may extend between two of the plurality of supplemental conduits. 
     A fourteenth aspect of the present disclosure may include any one of the first through thirteenth aspects, comprising a forming surface support comprising a first conduit support surface, the first forming surface, and the second forming surface. The first conduit support surface may be configured to support a lower portion of the first conduit wall. 
     A fifteenth aspect of the present disclosure may include the fourteenth aspect, wherein the forming surface support may comprise a refractory material support and a refractory metal layer disposed on the refractory material support to form at least the first forming surface and the second forming surface. 
     A sixteenth aspect of the present disclosure may include any one of the first through fifteenth aspects, further comprising a conduit support disposed between the first conduit and the second conduit. The conduit support may include a top surface and a bottom surface. 
     A seventeenth aspect of the present disclosure may include the sixteenth aspect, wherein the top surface of the conduit support may be shaped to support a lower portion of the second conduit wall, and the bottom surface may be shaped to receive an upper portion of the first conduit wall. 
     An eighteenth aspect of the present disclosure may include either the sixteenth or seventeenth aspects, wherein the conduit support may comprise a refractory material. 
     A nineteenth aspect of the present disclosure may include any one of the sixteenth through eighteenth aspects, wherein the first vertical wall may be coupled to a first side of the conduit support, and the second vertical wall may be coupled to a second side of the conduit support. 
     A twentieth aspect of the present disclosure may include any of the first through nineteenth aspects, wherein the first conduit wall, the second conduit wall, the first vertical wall, and the second vertical wall comprise a refractory metal. 
     A twenty-first aspect of the present disclosure may include the twentieth aspect, wherein the refractory metal comprises platinum or a platinum alloy. 
     A twenty-second aspect of the present disclosure may include any of the first through twenty-first aspects, in which a glass forming apparatus may include the forming body according to any of the first through twenty-first aspects. The glass forming apparatus may further include a first glass delivery system in fluid communication with an inlet of the first conduit and a second glass delivery system in fluid communication with an inlet of the second conduit. 
     A twenty-third aspect of the present disclosure may be directed to a method of forming a laminated glass ribbon having a plurality of glass layers. The method may include flowing a first molten glass into a first conduit in a forming body, the first conduit comprising a first conduit wall having an interior surface defining a first region and at least one slot extending through the first conduit wall and in fluid communication with the first region. The at least one slot of the first conduit may have a longest dimension aligned with a direction of flow through the first conduit. The method may further include passing the first molten glass through the at least one slot in the first conduit wall to merge with a first glass flow on a first side of the forming body, a second side of the forming body, or both. The method may further include flowing a second molten glass into a second conduit in the forming body. The second conduit may be positioned above and vertically aligned with the first conduit and may comprise a second conduit wall having an interior surface defining a second region and at least one slot extending through the second conduit wall and in fluid communication with the second region. The at least one slot of the second conduit may have a longest dimension aligned with a direction of flow through the second conduit. The method may further include passing the second molten glass through the at least one slot in the second conduit wall to merge with a second glass flow on the first side of the forming body, the second side of the forming body, or both. The method may further include merging the second glass flow with the first glass flow to form a continuous laminate glass ribbon having a plurality of molten glass layers fused together and drawing the continuous laminate glass ribbon downward from a root of the forming body. 
     A twenty-fourth aspect of the present disclosure may include the twenty-third aspect, wherein the method may comprise merging the second glass flow with the first glass flow at the root. 
     A twenty-fifth aspect of the present disclosure may include the twenty-third aspect, wherein the method may comprise merging the second glass flow with the first glass flow proximate the at least one slot in the first conduit wall on the first side of the forming body, the second side of the forming body, or both. 
     A twenty-sixth aspect of the present disclosure may include any one of the twenty-third through twenty-fifth aspects, wherein the first molten glass may have a glass composition different from a glass composition of the second molten glass. 
     A twenty-seventh aspect of the present disclosure may include any one of the twenty-third through twenty-sixth aspects, wherein the first glass flow may form a core glass, and the second glass flow may form a clad glass. 
     A twenty-eighth aspect of the present disclosure may include any one of the twenty-third through twenty-seventh aspects, wherein the first conduit may comprise a first slot extending through the first conduit wall at the first side of the forming body and a second slot extending through the first conduit wall at the second side of the forming body. The method may further include passing the first molten glass through the first slot to merge with a first portion of the first glass flow on the first side of the forming body, and passing the first molten glass through the second slot to merge with a second portion of first glass flow on the second side of the forming body. The method may further include merging the first portion of the first glass flow and the second portion of the first glass flow at the root to form a fused layer of molten glass. 
     A twenty-ninth aspect of the present disclosure may include any one of the twenty-third through twenty-eighth aspects, in which the method may further include annealing the continuous laminate glass ribbon. 
     A thirtieth aspect of the present disclosure may include any one of the twenty-third through twenty-ninth aspects, in which the method may further comprise separating the continuous laminate glass ribbon into a plurality of laminated glass sheets. 
     A thirty-first aspect of the present disclosure may include any one of the twenty-third through thirtieth aspects, in which the method may further include flowing a third molten glass into a third conduit in the forming body. The third conduit may be positioned above and vertically aligned with the first conduit and second conduit. The third conduit may comprise a third conduit wall having an interior surface defining a third region and at least one slot extending through the third conduit wall and in fluid communication with the third region. The at least one slot of the third conduit may have a longest dimension aligned with a direction of flow through the third conduit. The method may further include passing the third molten glass through the at least one slot in the third conduit wall to merge with a third glass flow on a first side of the forming body, a second side of the forming body, or both, and merging the third glass flow with the second glass flow, the first gas flow, or both. 
     It is to be understood that both the foregoing general description and the following detailed description describe various embodiments and are intended to provide an overview or framework for understanding the nature and character of the claimed subject matter. The accompanying drawings are included to provide a further understanding of the various embodiments, and are incorporated into and constitute a part of this specification. The drawings illustrate the various embodiments described herein, and together with the description serve to explain the principles and operations of the claimed subject matter. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  schematically depicts a laminate glass forming apparatus, according to one or more embodiments shown and described herein; 
         FIG. 2  schematically depicts a forming body provided as a reference for comparison to other forming body designs disclosed herein; 
         FIG. 3  schematically depicts a perspective view of a forming body for use with the laminate glass forming apparatus of  FIG. 1  and having a plurality of conduits, according to one or more embodiments shown and described herein; 
         FIG. 4  schematically depicts a cross-sectional view of the forming body of  FIG. 3  taken along section line  4 - 4 , according to one or more embodiments shown and described herein; 
         FIG. 5  schematically depicts a side cross-sectional view of the forming body of  FIG. 3 , according to one or more embodiments shown and described herein; 
         FIG. 6A  schematically depicts a side view of a first conduit of the forming body of  FIG. 3 , according to one or more embodiments shown and described herein; 
         FIG. 6B  schematically depicts a top view of a second conduit of the forming body of  FIG. 3 , according to one or more embodiments shown and described herein; 
         FIG. 7  graphically depicts a plot of a width of the slot opening (y-axis) as a function of position from an inlet end of the slot (x-axis) for a first conduit and a second conduit of the forming body of  FIG. 3 , according to one or more embodiments shown and described herein; 
         FIG. 8A  schematically depicts a cross-sectional view of the forming body of  FIG. 3 , according to one or more embodiments shown and described herein; 
         FIG. 8B  schematically depicts a cross-sectional view of another forming body for the laminate glass forming apparatus of  FIG. 1 , according to one or more embodiments shown and described herein; 
         FIG. 8C  schematically depicts a cross-sectional view of another forming body for the laminate glass forming apparatus of  FIG. 1 , according to one or more embodiments shown and described herein; 
         FIG. 8D  schematically depicts a cross-sectional view of yet another forming body for the laminate glass forming apparatus of  FIG. 1 , according to one or more embodiments shown and described herein; 
         FIG. 9  schematically depicts a cross-sectional view of a slot in a second conduit of the forming body of  FIG. 3 , according to one or more embodiments shown and described herein; 
         FIG. 10  schematically depicts a cross-sectional view of another embodiment of a second conduit of the forming body of  FIG. 3 , according to one or more embodiments shown and described herein; 
         FIG. 11  schematically depicts a cross-sectional view of still another embodiment of a second conduit of the forming body of  FIG. 3 , according to one or more embodiments shown and described herein; 
         FIG. 12  graphically depicts a plot of a ratio of flow over a first side of the forming body to the flow over a second side of the forming body for the second conduit (y-axis) as a function of roll angle (x-axis) for the second conduit configurations schematically depicts in  FIGS. 9, 10, and 11 , according to one or more embodiments shown and described herein. 
         FIG. 13  schematically depicts a cross-sectional view of another forming body for use with the laminate glass forming apparatus of  FIG. 1 , according to one or more embodiments shown and described herein; 
         FIG. 14A  schematically depicts a cross-sectional view of a portion of the forming body of  FIG. 3  proximate a first slot in a first conduit, according to one or more embodiments shown and described herein; and 
         FIG. 14B  schematically depicts a cross-sectional view of a portion of another forming body proximate a first slot in a first conduit, the forming body having a vertical offset between the first conduit and a first vertical wall, according to one or more embodiments shown and described herein. 
     
    
    
     DETAILED DESCRIPTION 
     Reference will now be made in detail to embodiments of forming bodies for glass forming apparatuses for producing continuous laminate glass ribbons, examples of which are illustrated in the accompanying drawings. Whenever possible, the same reference numerals will be used throughout the drawings to refer to the same or like parts. One embodiment of a forming body  200  of a glass forming apparatus is schematically depicted in  FIGS. 3-5 . In this embodiment, the forming body  200  of a glass forming apparatus includes a first conduit  210  that may include a first conduit wall  212  having an interior surface  213  defining a first region  216  and at least one slot (e.g., first slot  220  and/or second slot  222 ; narrow aperture, elongate opening, opening with aspect ratio of at least 5:1, 10:1, 20:1, 50:1, or more or less for narrowest to widest cross section; may be oval, elliptical, rectangular, or other geometries as disclosed) extending through the first conduit wall  212  and in fluid communication with the first region  216 . The slot of the first conduit  210  may have a longest dimension aligned with a direction of flow through the first conduit  210 . The forming body  200  of  FIG. 3  further includes a second conduit  230  disposed above and vertically aligned with the first conduit  210 . The second conduit  230  may include a second conduit wall  232  having an interior surface  233  defining a second region  236  and at least one slot  240  extending through the second conduit wall  232  and in fluid communication with the second region  236 . The slot  240  of the second conduit  230  may have a longest dimension aligned with a direction of flow through the second conduit  230 . The forming body  200  may further include a first vertical wall  250  and a second vertical wall  260 , each of which extend between an outer surface  234  of the second conduit wall  232  and an outer surface  214  of the first conduit wall  210  at a first side  206  and a second side  208 , respectively, of the forming body  200 . The forming body  200  may further include a first forming surface  270  and a second forming surface  272  extending from the outer surface  214  of the first conduit wall  212 . The first forming surface  270  and the second forming surface  272  converge at a root  274  of the forming body  200 . The forming bodies  200  of the present disclosure may enable the glass viscosity and glass flow distribution to be independently controlled, which may expand the possible combinations of glass compositions capable of being incorporated into the continuous laminate glass ribbon  102 . Additionally, the forming body  200  may provide a more stable confluence between the molten glass flows, which may reduce defects in the glass layers, among other aspects. 
     Directional terms as used herein—for example vertically, vertical, horizontal, horizontally, up, down, right, left, front, back, top, bottom—are made only with reference to the figures as drawn to facilitate the present disclosure and are not intended to imply absolutes or precise orientation unless expressly provided. For example, a “vertical” element may be oriented 80° from a “horizontal” element. Ranges of angles between vertical and horizontal elements may be 70° to 110° for example, such as 80° to 100°. Other such directional terms or terms with geometric meanings may also vary from absolute mathematical definitions. For example, “parallel” refers to side-by-side alignment in generally the same direction even if slightly offset, such as within 10° of one another. Likewise, “linear” is generally straight, not necessarily perfectly straight or always straight unless expressly provided. 
     Unless otherwise expressly stated, it is in no way intended that any method set forth herein be construed as requiring that its steps be performed in a specific order, nor that specific orientations be required with any apparatus. Accordingly, where a method claim does not actually recite an order to be followed by its steps, or that any apparatus claim does not actually recite an order or orientation to individual components, or it is not otherwise specifically stated in the claims or description that the steps are to be limited to a specific order, or that a specific order or orientation to components of an apparatus is not recited, it is in no way intended that an order or orientation be inferred, in any respect. This holds for any possible non-express basis for interpretation, including: matters of logic with respect to arrangement of steps, operational flow, order of components, or orientation of components; plain meaning derived from grammatical organization or punctuation, and; the number or type of embodiments described in the specification. 
     As used herein, the singular forms “a,” “an” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a” component includes embodiments having two or more such components, unless the context clearly indicates otherwise. 
     The glass forming apparatus  100  and forming bodies disclosed herein may be employed to produce continuous laminate glass ribbons  102  for making laminate glass sheets. Continuous laminate glass ribbons  102  and laminate glass sheets made therefrom may include a plurality of glass layers, such as 2, 3, 4, 5, 6, or more than 6 layers of glass. In some embodiments, the continuous laminate glass ribbon  102  may include a core glass layer and at least two clad glass layers, where the core glass layer is disposed between the two clad glass layers. Each of the layers of glass may be fused together. In some embodiments, one or more of the glass layers may have a different glass composition than the other glass layers. The different glass compositions in the different glass layers may have different properties, such as coefficients of thermal expansion (CTE), Young&#39;s modulus, optical properties, chemical resistance, or other properties, which may provide certain features, such as improved strength, modified optical properties, or other features, to the laminated glass sheets produced from the continuous laminate glass ribbons  102 . 
     Referring now to  FIG. 1 , a glass forming apparatus  100  for making laminate glass articles, such as continuous laminate glass ribbons  102 , through a fusion draw process is schematically depicted. The glass forming apparatus  100  may generally include a first molten glass delivery system  110 , a second molten glass delivery system  150 , and a forming body  200 . The first molten glass system  110  may be in fluid communication with a first inlet  202  of the forming body  200  and may be operable to deliver a first molten glass to the first inlet  202  of the forming body  200 . The second molten glass system  150  may be in fluid communication with a second inlet  204  of the forming body  200  and may be operable to deliver a second molten glass to the second inlet  204  of the forming body  200 . 
     The first molten glass system  110  may include a first melting vessel  114  that receives a first batch material  115  from a first storage bin  116 . The first batch material  115  can be introduced to the first melting vessel  114  by a first batch delivery device  117  powered by a motor  118 . An optional first controller  120  may be provided to activate the motor  118  and a first molten glass level probe  122  can be used to measure the glass melt level within a first standpipe  124  and communicate the measured information to the first controller  120 . The first molten glass system  110  can also include a first fining vessel  128 , such as a fining tube, coupled to the first melting vessel  114  by way of a first connecting tube  126 . A first mixing vessel  132  may be coupled to the first fining vessel  128  with a second connecting tube  130 . A first delivery vessel  136  may be coupled to the first mixing vessel  132  with a first delivery conduit  134 . As further illustrated, a first downcomer  138  may be coupled to the first delivery vessel  136  and may be operable to deliver glass melt from the first delivery vessel  136  to a first delivery tube  140  in fluid communication with the first inlet  202  of the forming body  200 . 
     The second molten glass system  150  may include a second melting vessel  154  that receives a second batch material  155  from a second storage bin  156 . The second batch material  155  can be introduced to the second melting vessel  154  by a second batch delivery device  157  powered by a motor  158 . An optional second controller  160  may be provided to activate the motor  158 , and a second molten glass level probe  162  can be used to measure the glass melt level within a second standpipe  164  and communicate the measured information to the second controller  160 . The second molten glass system  150  can also include a second fining vessel  168 , such as a fining tube, coupled to the second melting vessel  154  by way of a third connecting tube  166 . A second mixing vessel  172  may be coupled to the second fining vessel  168  with a fourth connecting tube  170 . A second delivery vessel  176  may be coupled to the second mixing vessel  172  with a second delivery conduit  174 . As further illustrated in  FIG. 1 , a second downcomer  178  may be coupled to the second delivery vessel  176  and may be operable to deliver glass melt from the second delivery vessel  176  to second delivery tube  180  in fluid communication with the second inlet  204  of the forming body  200 . 
     The first melting vessel  114 , the second melting vessel  154 , or both, are typically made from a refractory material, such as refractory (e.g., ceramic) brick. The glass forming apparatus  100  may further include components that can be made from electrically conductive refractory metals such as, for example, platinum or platinum-containing metals 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 alloys thereof and/or zirconium dioxide. The platinum-containing components can include, but are not limited to, one or more than one of the first connecting tube  126 , the first fining vessel  128 , the second connecting tube  130 , the first standpipe  124 , the first mixing vessel  132 , the first delivery conduit  134 , the first delivery vessel  136 , the first downcomer  138 , the first delivery tube  140 , the third connecting tube  166 , the second fining vessel  168 , the fourth connecting tube  170 , the second standpipe  164 , the second mixing vessel  172 , the second delivery conduit  174 , the second delivery vessel  176 , the second downcomer  178 , the second delivery tube  180 , or combinations of these. 
     Referring to  FIG. 1 , in operation, the first batch material  115 , specifically batch material for forming glass, is fed from the first storage bin  116  into the first melting vessel  114  with the first batch delivery device  117 . The first batch material  115  is melted into a first molten glass in the first melting vessel  114 . The first molten glass passes from the first melting vessel  114  into the first fining vessel  128  through the first connecting tube  126 . Dissolved gasses, which may result in glass defects, are removed from the first molten glass in the first fining vessel  128 . The first molten glass then passes from the first fining vessel  128  into the first mixing vessel  132  through the second connecting tube  130 . The first mixing vessel  132  homogenizes the first molten glass, such as by stirring, and the homogenized first molten glass passes through the first delivery conduit  134  to the first delivery vessel  136 . The first delivery vessel  136  discharges the homogenized first molten glass through first downcomer  138  and into the first delivery tube  140  in fluid communication with the first inlet  202  of the forming body  200 . 
     Similarly, the second batch material  155 , also specifically batch material for forming glass, is fed from the second storage bin  156  into the second melting vessel  154  with the second batch delivery device  157 . The second batch material  155  is melted into a second molten glass in the second melting vessel  154 . The second molten glass passes from the second melting vessel  154  into the second fining vessel  168  through the third connecting tube  166 . Dissolved gasses, which may result in glass defects, are removed from the second molten glass in the second fining vessel  168 . The second molten glass then passes from the second fining vessel  168  into the second mixing vessel  172  through the fourth connecting tube  170 . The second mixing vessel  172  homogenizes the second molten glass, such as by stirring, and the homogenized second molten glass passes through the second delivery conduit  174  to the second delivery vessel  176 . The second delivery vessel  176  discharges the homogenized second molten glass through second downcomer  178  and into the second delivery tube  180  in fluid communication with the second inlet  204  of the forming body  200 . Operation of the forming body  200  will be described in further detail later in this Description. 
     Referring now to  FIG. 2 , a forming body  10  comprising a double overflow isopipe for producing a laminate fusion glass ribbon  12  is schematically depicted for comparison to other embodiments disclosed herein. The forming body  10  generally includes a first overflow isopipe  20 , a second overflow isopipe  30  positioned above and vertically aligned with the first overflow isopipe  20 , a first forming surface  40 , and a second forming surface  50 . The first overflow isopipe  20  may be similar in shape and function to a single isopipe for making a single-layer fusion-draw glass ribbon. The first overflow isopipe  20  includes a pair of first weirs  22  that define a first trough  24  there between. The first forming surface  40  and the second forming surface  50  extend from the first overflow isopipe in a vertically downward direction (i.e., the −Z direction of the coordinate axes depicted in  FIG. 2 ) and converge towards one another, joining at a lower (bottom) edge of the double overflow isopipe  10 , which may also be referred to as the root  60 . In operation, a molten core glass  14  may be passed into the first trough  24  of the first overflow isopipe  20 . The molten core glass  14  may overflow the first weirs  22  and flow down (i.e., in the −Z direction of the coordinate axis of  FIG. 2 ) the first forming surface  40  and the second forming surface  50  in two separate flows of the molten core glass  14 . The two separate flows of molten core glass  14  may converge at the root  60  and fuse together to form a core layer of the laminate fusion glass ribbon  12 . 
     The second overflow isopipe  30  is spaced apart from the first overflow isopipe  20  and includes a pair of second weirs  32  that define a second trough  34 . The second overflow isopipe  30  differs from the first overflow isopipe  20  in that the second overflow isopipe  30  does not include converging forming surfaces that converge at a root. Instead, the separate molten glass flows from the second overflow isopipe  30  free fall downward (i.e., in the −Z direction of the coordinate axis of  FIG. 2 ) from the outer surface of the second overflow isopipe  30  into contact with the molten core glass  14 . In operation, a molten clad glass  16  may be passed into the second trough  34  of the second overflow isopipe  30 . The molten clad glass  16  may overflow the second weirs  32  and flow vertically downward (i.e., in the −Z direction) along the outer surfaces of the second overflow isopipe  30  in two separate flows of molten glass. At the gap  70  between the first overflow isopipe  20  and the second overflow isopipe  30 , the two separate molten glass flows of the molten clad glass  16  freefall downward (i.e., −Z direction) across the gap and onto the two separate molten glass flows of the molten core glass  14 . Each of the flows of molten clad glass  16  fuse with a flow of the molten core glass  14  and continue down the first forming surface  40  and second forming surface  50 , respectively, to the root  60 . The molten clad glass  16  forms the clad layer of the laminate fusion glass ribbon  12  at the root  60 . The laminate fusion glass ribbon  12  may be drawn from the root  60  on the draw plane P in a vertically downward direction (i.e., in the −Z direction of the coordinate axis of  FIG. 2 ) by pulling rolls (not shown). The laminate fusion glass ribbon  12  may be further processed downstream of the forming body  10 , such as by segmenting the glass laminate fusion glass ribbon  12  into discrete glass sheets, rolling the laminate fusion glass ribbon  12  upon itself, and/or applying one or more coatings to the glass ribbon  12 . 
     The forming body  10  may enable formation of the laminate fusion glass ribbon  12  having a plurality of glass layers. However, such a forming body  10 , as shown in  FIG. 2 , comprising the double overflow isopipes as shown may require a very precise positioning system for the first overflow isopipe  20  and the second overflow isopipe  30  relative to each other to provide uniform thickness of all three layers of the laminate fusion glass ribbon  12 . Additionally, instability of the free falling molten clad glass  16  across the gap  70  between the second overflow isopipe  30  and the first overflow isopipe  20  may lead to variations in the thickness of one or more of the glass layers and/or the overall thickness of the laminate fusion glass ribbon  12  and the laminate glass sheets produced therefrom in some such designs. 
     Further, the first overflow isopipe  20  for the core glass and the second overflow isopipe  30  for the clad glass may both be designed to deliver uniform molten glass flow only when an isopipe K constant is equal to a predefined value. The isopipe K constant for an isopipe for a fusion draw process may be based on and/or proportional to the multiplication product of the molten glass flow rate and the viscosity of the molten glass. Because the overflow isopipes of the forming body  10  may be designed based on the K constant of the first overflow isopipe  20  and the second overflow isopipe  30 , the molten glass flow rate and viscosity of the molten glass in the isopipe troughs may not be changed independently in some such designs. This could limit the available process window of the fusion process for producing laminate glass ribbons using a forming body  10  for example. In particular, an inability to vary the molten glass flow rate and viscosity of the molten glass independent of each other may limit the ability of the forming body  10  to produce different thicknesses of each layer of glass and may limit the range of different glass combinations that may be used for the laminate glass ribbons by limiting the viscosity range of the molten glass compositions for example. 
     By contrast, other forming bodies disclosed herein overcome such deficiencies in forming body  10  to provide greater consistency in the thicknesses of individual glass layers and overall thickness of the continuous laminate glass ribbon  102 . The other forming bodies disclosed herein may also provide for a wider range of glass compositions to be incorporated into the continuous laminate glass ribbon  102 . Referring to  FIGS. 3-6 , the forming bodies  200  disclosed herein may include a first conduit  210  and a second conduit  230  positioned above and vertically aligned with (i.e., aligned in the +/−Z direction of the coordinate axis of  FIGS. 2-6 ) the first conduit  210 . The first conduit  210  may include the first inlet  202  in fluid communication with the first molten glass system  110  ( FIG. 1 ), and the second conduit  230  may have a second inlet  204  in fluid communication with the second molten glass system  150  ( FIG. 1 ). Referring to  FIGS. 3-5 , the first conduit  210  may include a first conduit wall  212  having an interior surface  213  defining a first region  216 . The first conduit  210  may include at least one slot (e.g., first slot  220  and/or second slot  222 ) extending through the first conduit wall  212 . 
     The second conduit  230  may include a second conduit wall  232  having an interior surface  233  defining a second region  336 . The second conduit  230  may include at least one slot  240  extending through the second conduit wall  232 . The forming bodies  200  disclosed herein may also include a first vertical wall  250  extending vertically (i.e., shown in the +/−Z direction of the coordinate axis in  FIGS. 3-5 ) between an outer surface  214  of the first conduit  210  and an outer surface  234  of the second conduit  230  at the first side  206  of the forming body  200 . The forming bodies  200  may include a second vertical wall  260  extending vertically (i.e., in the +/−Z direction of the coordinate axis in  FIGS. 3-5 ) between the outer surface  214  of the first conduit  210  and the outer surface  234  of the second conduit  230  at the second side  208  of the forming body  200 . The forming bodies  200  may also include a first forming surface  270  and a second forming surface  272 , each of which extend from the first conduit  210  in a vertically downward direction (i.e., the −Z direction of the coordinate axis in  FIGS. 3-5 ) and converge towards one another, joining at the root  274  of the forming body  200 . 
     The first vertical wall  250  and second vertical wall  260  may each provide a continuous surface extending between the second conduit  230  and the first conduit  210 , which may provide a smooth and stable confluence of the second molten glass  231  with the first molten glass  211  without free fall of second molten glass  231  into contact with the first molten glass. By eliminating free fall of the second molten glass  231  between the second conduit  230  and contact with the first molten glass  211 , the forming bodies  200  of the present disclosure may reduce or prevent flow instabilities and air entrapment at the confluence between the second molten glass  231  and the first molten glass  211 , particularly at low glass flow density and viscosity. Reduced flow instability at the confluence of the second molten glass  231  with the first molten glass  211  may improve the consistency in the thickness of the continuous laminate glass ribbon  102  and/or the thickness of any of the plurality of glass layers of the continuous laminate glass ribbon  102 . Further, the forming bodies  200  of the present disclosure may not require complicated and expensive independent positioning systems for positioning each of two separate isopipes relative to one another. 
     The first conduit  210  having at least one slot (e.g., first slot  220  and/or second slot  222 ) and the second conduit  230  having at least one slot  240  may reduce or eliminate the interdependence of glass viscosity and glass flow rate, which may enable independent control of glass flow profiles and glass viscosities. Independent control of glass flow and glass viscosity may broaden the available combinations of glass compositions that can be incorporated into the continuous laminate glass ribbon  102 . Additionally, independent control of glass flow profile and glass viscosity can broaden the range of possible thickness ratios between the individual glass layers of the continuous laminate glass ribbon  102 . Independent control of glass flow profiles may also enable delivering a target thickness ratio profile across the draw and reduce or prevent inconsistencies, such as problematic clad beads in case of core/clad lamination. 
     In addition to these features, the forming bodies  200  disclosed herein may allow for straightforward extension to an arbitrary number of layers glass layers by adding one or a plurality of supplemental conduits to the forming body  200 . The forming bodies  200  may also enable flexibility in independently varying the width of each of the glass layers, such as making one glass layer narrower than another glass layer or keeping all of the glass layers the same width. The number of slots and location of the slots in each of the conduits may be varied to modify the number of glass layers in the continuous laminate glass ribbon  102 . With the use of batch platinum melters and glass cullet, the glass forming apparatus  100  may enable quick change of glass compositions for one or more layers of the continuous laminate glass ribbon in order to change the properties or thickness of one or more of the glass layers. Additionally, the glass forming apparatus  100  and forming bodies  200  may enable short start-up times and quick transition between glass compositions, among other features. 
     Referring to  FIGS. 4 and 5 , as previously discussed, the forming bodies  200  disclosed herein may include the first conduit  210  comprising a first conduit wall  212 . The first conduit wall  212  may have an interior surface  213  defining a first region  216  and at least one slot (e.g., first slot  220 , second slot  222 , or both) extending through the first conduit wall  212 . The first region  216  may be fully enclosed by the first conduit wall  212  such that the first conduit  210  does not have an open side. The first conduit wall  212  may also have an outer surface  214  facing outward from the first region  216 . Referring to  FIG. 5 , the first conduit  210  may have a first conduit inlet end  217  proximate to and in fluid communication with a first inlet  202  ( FIG. 3 ) of the forming body  200 . The first conduit  210  may also have a first conduit compression end  218 , which may be an end of the first conduit  210  opposite the first conduit inlet end  217 . The first conduit wall  212  may extend along a longitudinal length Li of the first conduit  212  from the first conduit inlet end  217  to the first conduit compression end  218 . The first region  216  may be in fluid communication with the first inlet  202  ( FIG. 3 ) of the forming body  200  by way of the first conduit inlet end  217 . A first molten glass  211  from the first molten glass system  110  ( FIG. 1 ) may flow into the first conduit  210  through the first conduit inlet end  217  and may flow through the first region  216  of the first conduit  210  in a direction from the first conduit inlet end  217  towards the first conduit compression end  218 . 
     The first conduit wall  212  may be generally cylindrical in shape. The interior surface  213  of the first conduit wall  212  may have a cross-sectional shape conducive to flowing a molten glass through the entire length L 1  of the first conduit  210 . In some embodiments, the interior surface  213  of the first conduit wall  212  may have a cross-sectional shape that is circular in shape. Other cross-sectional shapes are contemplated, such as but not limited to ovoid, polygonal, or other shapes. Referring to  FIG. 5 , in some embodiments, the cross-sectional area of the first region  216  defined by the interior surface  213  of the first conduit wall  212  may decrease along the length L 1  of the first conduit  210  from the first conduit inlet end  217  to the first conduit compression end  218 . In some embodiments, the cross-sectional area of the first conduit wall  212  may stay the same along the length L 1  of the first conduit  210 . Referring now to  FIG. 4 , in some embodiments, the first conduit  210  may have a centerline  215  that may be vertically aligned with the draw plane P of the forming body  200 . 
     Referring to  FIG. 4 , the first conduit  210  includes at least one slot (e.g., first slot  220 , second slot  222 , or both) extending through the first conduit wall  212 . In some embodiments, the first conduit  210  may include at least a first slot  220  and a second slot  222 . The first slot  220  may be positioned at the first side  206  of the forming body  200 , and the second slot  222  may be positioned at the second side  208  of the forming body  200 , the second side  208  being a side opposite the first side  206 . The slot in the first conduit wall  212  may be in fluid communication with the first region  216 . In some embodiments, the first slot  220 , the second slot  222 , or both, may be in fluid communication with the first region  216 . Fluid communication between the first region  216  and the first slot  220  and second slot  222  may enable the first molten glass  211  to flow from the first region  216  through the first slot  220  and the second slot  222  to the outer surface  214  of the first conduit wall  212 . 
     Referring to  FIG. 6A , the first slot  220  and the second slot  222  may each be characterized by a slot length L S  and a slot width W S , which is less than the slot length L S . The dimensions and proportions in  FIG. 6A  may be exaggerated for purposes of illustration. Although  FIG. 6A  illustrates only the first slot  220 , it is understood that the second slot  22  may have any of the features, dimensions, or characteristics described herein in relation to the first slot  220 . The first slot  220 , the second slot  222 , or both, may have a longest dimension (e.g., the slot length L S ) aligned with a direction of flow of the first molten glass  211  through the first conduit  210  from the first conduit inlet end  217  to the first conduit compression end  218 . In some embodiments, the slot length L S  of the first slot  220 , the second slot  222 , or both, may be parallel to the draw plane P ( FIG. 4 ) of the forming body  200 . The second slot  222  may be the same or different from the first slot  220 . 
     The first slot  220  and the second slot  222  may have a geometry that provides a target glass flow distribution along the slot length L S  of the first slot  220  and the second slot  222 . To provide a consistent molten glass flow along the slot length L S  of each slot, the geometry of the slot may provide a decrease in the impedance to flow of molten glass along the slot length L S  from the first conduit inlet end  217  towards the first conduit compression end  218 . The decreasing impedance of the first slot  220  and second slot  222  along the slot length L S  may compensate for the viscous friction of the molten glass flow through the first conduit  210 . The slot geometry of the first slot  220  and the second slot  222  may depend on the dimensions of the first conduit  210  and the target slot length L S  of the first slot  220  and/or the second slot  222 . The impedance may be tuned by changing slot width W S  of the slot, the thickness of the first conduit wall  212 , or the inner dimensions (e.g., inner radius) of the interior surface  213  of the first conduit wall  212 . In some embodiments, the slot width W S  of the first slot  220 , the second slot  222 , or both may increase along the slot length L S  from the first conduit inlet end  217  to the first conduit compression end  218 . Referring to  FIG. 7 , the slot width W S  (y-axis) of the first slot  220  or the second slot  222  is graphically depicted as a function of distance from the inlet end  217  of the first conduit  210 , and is indicated with reference number  702 . As shown in  FIG. 7 , the slot width W S  may increase as the distance from the first conduit inlet end  217  increases. 
     As shown in  FIG. 6A , in some embodiments, the first slot  220 , the second slot  222 , or both may be a single continuous slot along the slot length L S . In other embodiments, the first slot  220 , the second slot  222 , or both, may each include a perforated slot. The perforated slot may include a plurality of smaller slots aligned along a direction of flow of the first molten glass  211  through the first conduit  210 . In some embodiments, each of the smaller slots of the perforated slot may have a widened portion at either end of the smaller slot to provide additional glass flow to compensate for the discontinuous regions between the smaller slots. In some embodiments, the perforated slots may exhibit improved creep resistance compared to continuous slots, which may enable better control when producing wider continuous laminate glass ribbons  102 . In some embodiments, the at least one slot in the first conduit wall  212  may include a plurality of slots, wherein the plurality of slots are aligned along a linear path parallel to the flow direction of the first conduit  210 . Additional features, geometries, and characteristics of the first conduit  210 , first conduit wall  212 , and the slots (e.g., first slot  220  and second slot  222 ) in the first conduit wall  212  are described in co-pending U.S. Provisional Patent Application No. 62/717,173, filed on Aug. 10, 2018, the entire contents of which are incorporated by reference in this disclosure. 
     Referring again to  FIGS. 3-5 , as previously discussed, the forming bodies  200  disclosed herein may include a second conduit  230 . The second conduit  230  may be disposed vertically above (i.e., in the +Z direction of the coordinate axis in  FIGS. 3-5 ) and may be vertically aligned with (i.e., aligned in the +/−Z direction of the coordinate axis in  FIGS. 3-5 ) the first conduit  210 . In some embodiments, a centerline  235  of the second conduit  230  may be vertically aligned with the centerline  215  of the first conduit  210 . The second conduit  230  may include a second conduit wall  232 . The second conduit wall  232  may have an interior surface  233  defining a second region  236  and at least one slot  240  extending through the second conduit wall  232 . The second region  236  may be fully enclosed by the second conduit wall  232  such that the second conduit  230  does not have an open side. The second conduit wall  232  may also have an outer surface  234  facing outward from the second region  236 . Referring to  FIG. 5 , the second conduit  230  may have a second conduit inlet end  237  proximate to and in fluid communication with a second inlet  204  ( FIG. 3 ) of the forming body  200 . The second conduit  230  may also have a second conduit compression end  238 , which may be an end of the second conduit  230  opposite the second conduit inlet end  237 . 
     The second conduit wall  232  may extend along a longitudinal length L 2  of the second conduit  232  from the second conduit inlet end  237  to the second conduit compression end  238 . The second region  236  may be in fluid communication with the second inlet  204  ( FIG. 3 ) of the forming body  200  by way of the second conduit inlet end  237 . A second molten glass  231  from the second molten glass system  150  ( FIG. 1 ) may flow into the second conduit  230  through the second conduit inlet end  237  and may flow through the second region  236  of the second conduit  230  in a direction from the second conduit inlet end  237  towards the second conduit compression end  238 . Referring to  FIG. 5 , in some embodiments, the second conduit  230  may be oriented so that a direction of flow of the second molten glass  231  through the second conduit  230  is opposite the direction of flow of the first molten glass  211  through the first conduit  210 . Alternatively, in other embodiments, the first conduit  210  and the second conduit  230  may be oriented so that the direction of flow in the second conduit  230  is the same as the direction of flow in the first conduit  210 . 
     Referring to  FIGS. 4 and 5 , the second conduit wall  232  may be generally cylindrical in shape. The interior surface  233  of the second conduit wall  232  may have a cross-sectional shape conducive to flowing a molten glass through the entire length L 2  of the second conduit  230 . In some embodiments, the interior surface  233  of the second conduit wall  232  may have a cross-sectional shape that is circular. Other cross-sectional shapes are contemplated, such as but not limited to ovoid, polygonal, or other shape. Referring to  FIG. 5 , in some embodiments, the cross-sectional area of the second region  236  defined by the interior surface  233  of the second conduit wall  232  may decrease along the length L 2  of the second conduit  230  from the second conduit inlet end  237  to the second conduit compression end  238 . In some embodiments, the cross-sectional area of the second conduit wall  232  may stay the same along the length L 2  of the second conduit  230 . The shape of an outer surface  234  of the second conduit wall  232  may be the same or different than the shape of the outer surface  214  of the first conduit wall  212 . For example, an outer diameter of the second conduit wall  232  may be the same or different than an outer diameter of the first conduit wall  212 . Referring now to  FIG. 4 , in some embodiments, the second conduit  230  may have a centerline  235  that may be vertically aligned with the draw plane P of the forming body  200 , with the centerline  215  of the first conduit  210 , or both. 
     Referring to  FIG. 4 , the second conduit  230  may include at least one slot  240  extending through the second conduit wall  232 . In some embodiments, the slot  240  may be position in a topmost portion of the second conduit wall  232 . The slot  240  in the second conduit wall  232  may be in fluid communication with the second region  236 . Fluid communication between the second region  236  and the slot  240  may enable the second molten glass  231  to flow from the second region  236  through the slot  240  to the outer surface  234  of the second conduit wall  232 . Referring to  FIG. 8B , in some embodiments, the second conduit  230  may include at least a first slot  241  and a second slot  242 . The first slot  241  of the second conduit  230  may be positioned at the first side  206  of the forming body  200 , and the second slot  242  of the second conduit  230  may be positioned at the second side  208  of the forming body  200 , the second side  208  being opposite the first side  206 . The first slot  241 , the second slot  242 , or both, may be in fluid communication with the second region  236  to enable the second molten glass  231  to flow from the second region  236  through the first slot  241 , the second slot  242 , or both to the outer surface  234  of the second conduit wall  232 . 
     The slot  240 , the first slot  241 , and/or the second slot  242  in the second conduit wall  232  may have any of the features, geometries, or characteristics previously described in reference to the first slot  220  and the second slot  222  of the first conduit  210 . Referring now to  FIG. 6B , the slot  240  in the second conduit wall  232  may be characterized by a slot length L S  and a slot width W S , which is less than the slot length L S . The dimensions and proportions in  FIG. 6B  may be exaggerated for purposes of illustration. The slot  240  in the second conduit wall  232  may have a longest dimension (e.g., the slot length L S ) aligned with a direction of flow of the second molten glass  231  through the second conduit  230 . In some embodiments, the slot length L S  of the slot  240  may be parallel to the draw plane P ( FIG. 4 ) of the forming body  200 . 
     The slot  240  may have a geometry that provides a target glass flow distribution along the slot length L S . To provide a consistent molten glass flow along the slot length L S , the geometry of the slot may result in a decrease in the impedance to flow of molten glass along the slot length L S  from the second conduit inlet end  237  towards the second conduit compression end  238 . The decreasing impedance of the slot  240  along the slot length L S  may compensate for the viscous friction of the molten glass flow through the second conduit  230 . The slot geometry of the slot  240  may depend on the dimensions of the second conduit  230  and the target slot length L S . The impedance may be tuned by changing slot width W S  of the slot  240 , the thickness of the second conduit wall  232 , or the inner dimensions (e.g., inner radius) of the interior surface  233  of the second conduit wall  232 . In some embodiments, the slot width W S  of the slot  240  may increase along the slot length L S . Referring to  FIG. 7 , the slot width W S  (y-axis) of the slot  240  in the second conduit wall  232  is graphically depicted as a function of distance from the inlet end  237  of the second conduit  230 , and is indicated with reference number  704 . As shown in  FIG. 7 , the slot width W S  increases as the distance from the second conduit inlet end  237  increases. Series  704  is representative of a single slot  240  in the top portion of the second conduit wall  232 . The single slot  240  may have a larger slot width W S  compared to each of the first slot  220  and second slot  222  of the first conduit  210  (reference  702 ) due to the increased molten glass flow rate needed to produce two flows of the second molten glass  231 , one down each side of the forming body  200 . 
     As shown in  FIG. 6B , in some embodiments, the slot  240  may be a single continuous slot along the slot length L S . In other embodiments, the slot  240  may be a perforated slot comprising a plurality of smaller slots aligned along a direction of flow of the second molten glass  231  through the second conduit  230 . In some embodiments, each of the smaller slots of the perforated slot may have a widened portion at either end of the smaller slot to provide additional glass flow to compensate for the discontinuous regions between the smaller slots. In some embodiments, the perforated slots may exhibit improved creep resistance compared to continuous slots, which may enable better control when producing wider continuous laminate glass ribbons  102 . In some embodiments, the at least one slot  240  in the second conduit wall  232  may include a plurality of slots, wherein the plurality of slots are aligned along a linear path parallel to the flow direction of the second conduit  230 . Additional features, geometries, and characteristics of the second conduit  230 , second conduit wall  232 , and the slot  240  in the second conduit wall  232  are described in co-pending U.S. Provisonal Patent Application No. 62/717,173, filed on Aug. 10, 2018, the entire contents of which are incorporated by reference in this disclosure. when the second conduit  230  includes the first slot  241  and the second slot  242 , the first slot  241  and/or the second slot may have any of the features, dimensions, or characteristics described herein for the flow  240 . 
     The first conduit wall  212 , the second conduit wall  232 , or both, may be constructed of a refractory metal capable of withstanding the temperatures experienced during formation of the continuous laminate glass ribbon  102  without degrading or reacting with the constituents of the first molten glass  211  or the second molten glass  231 . The refractory metal may be platinum, platinum alloy, or other metals or metal alloys. In some embodiments, the first conduit wall  212 , the second conduit wall  232 , or both, may be platinum or a platinum-alloy. All-platinum or platinum alloy surfaces of the first conduit wall  212 , second conduit tool  232 , and other components of the forming body  200  may reduce or prevent compatibility issues between the glass compositions and refractory materials used for overflow-style isopipes. 
     Referring again to  FIG. 4 , the forming bodies  200  may include a conduit support  252  disposed between the first conduit  210  and the second conduit  230 . The conduit support  252  may have an upper surface  254  and a lower surface  256 . The upper surface  254  may be configured to support a lower portion of the second conduit wall  232 , which may be disposed vertically above (i.e., in the +Z direction of the coordinate axis of  FIG. 4 ) the conduit support  252 . In some embodiments, the upper surface  254  of the conduit support  252  may have a shape conforming to at least a portion of a contour of the outer surface  234  of the second conduit wall  232  in the lower portion of the second conduit  230 . In some embodiments, the upper surface  254  of the conduit support  252  may include one or a plurality of support beams (not shown) shaped to support at least a portion of the lower portion of the second conduit  230 . The conduit support  252  may support from 25% to 80% of the lower portion of the outer surface  234  of the second conduit wall  232 . The conduit support  252  may be operable to reduce or prevent deformation of the second conduit  230  in a vertical direction (e.g., in the +/−Z direction of the coordinate axis in  FIG. 4 ) and/or in a horizontal direction (i.e., in the +/−Y direction of the coordinate axis in  FIG. 4 ) during formation of the continuous laminate glass ribbon  102 . 
     The lower surface  256  of the conduit support  252  may be configured to support an upper portion of the first conduit wall  212 , which may be disposed vertically below (i.e., in the −Z direction of the coordinate axis of  FIG. 4 ) the conduit support  252 . In some embodiments, the lower surface  256  of the conduit support  252  may have a shape conforming to at least a portion of the contour of the outer surface  214  of the first conduit wall  212  in the upper portion of the first conduit  210 . In some embodiments, the lower surface  256  of the conduit support  252  may include one or a plurality of support beams (not shown) shaped to support at least a portion of the upper portion of the first conduit  210 . The conduit support  252  may support from 25% to 80% of the upper portion of the outer surface  214  of the first conduit wall  212 . The conduit support  252  may be operable to reduce or prevent deformation of the second conduit  230  in a vertical direction (e.g., in the +/−Z direction of the coordinate axis in  FIG. 4 ) and/or in a horizontal direction (i.e., in the +/−Y direction of the coordinate axis in  FIG. 4 ) during formation of the continuous laminate glass ribbon  102 . For example, in some embodiments, the conduit support  252  may support the weight of the second conduit  230  and second molten glass  231  to prevent the weight of the second conduit  230  from deforming the upper portion of the first conduit wall  212  vertically downward (i.e., in the −Z direction of the coordinate axis in  FIG. 4 .). The conduit support  252  may also prevent hydrostatic forces from the first molten glass  211  and/or the second molten glass  231  from deforming the first conduit wall  212  and/or the second conduit wall  232  outward. 
     The conduit support  252  may be formed from a support material capable of withstanding the temperatures experienced during formation of the continuous laminate glass ribbon  102  without deforming or experiencing creep. In some embodiments, the conduit support  252  can be constructed from a support material having a creep rate from 1×10 −12  per second (s −1 ) to 1×10 −14  s −1  under a pressure of from 1 MPa to 5 MPa and at a temperature of 1400° C. In some embodiments, the conduit support  252  may be constructed of a refractory material, such as, but limited to, one or more refractory metals, ceramic materials, or other refractory materials. In some embodiments, the conduit support  252  may include a ceramic material, such as, but not limited to, zircon (e.g., zirconium silicate), low creep zircon, silicon carbide, xenotime, alumina-based refractory ceramics, or combinations of these. In some embodiments, the conduit support  252  may include a support material that is porous. The conduit support  252  can withstand creep under high stress and temperature to enable maintenance of the position and shape of the first conduit wall  212  and the second conduit wall  232  during formation of the continuous laminate glass ribbon  102 . 
     In some embodiments, the refractory material of the conduit support  252  may be incompatible for physical contact with the refractory metal of the first conduit wall  212  and second conduit wall  232 . For example, in some embodiments, the first conduit wall  212 , the second conduit wall  232 , or both, may include platinum (e.g. platinum or platinum alloy), and the conduit support  252  may include silicon carbide, which may corrode or otherwise chemically react when contacted with platinum. In some embodiments, the conduit support  252  may include a layer of intermediate material (not shown) disposed between the upper surface  254  of the conduit support  252  and the second outer wall  232  of the second conduit  230 , between the lower surface  256  of the conduit support  252  and the first outer wall  212  of the first conduit  210 , or both. The intermediate material may be operable to separate the refractory material of the conduit support  252  from the platinum-containing metal or other refractory metal of the first conduit wall  212  and/or the second conduit wall  232 . 
     In some embodiments, the forming bodies  200  may include a conduit support vacuum tube  264  in fluid communication with the support material of the conduit support  252 . The vacuum tube  264  may be fluidly coupled to a vacuum system (not shown), such as a vacuum pump or Venturi system. The vacuum system may be operable to create a vacuum within the vacuum tube  264  and within the support material of the conduit support  252 . 
     Referring to  FIG. 4 , the forming bodies  200  may include the first vertical wall  250  and the second vertical wall  260 , both of which may extend generally vertically (i.e., in generally the +/−Z direction of the coordinate axis of  FIG. 4 ) between the outer surface  234  of the second conduit wall  232  and the outer surface  214  of the first conduit wall  212 . An outer surface  251  of the first vertical wall  250  and an outer surface  261  of the second vertical wall  260  may provide continuous surfaces over which the flows of the second molten glass  231  from the second conduit  230  can flow from the outer surface  234  of the second conduit wall  232  into contact with the first molten glass  211  from the first conduit  210 . Thus, the first vertical wall  250  and the second vertical wall  260  may eliminate any gaps or air pockets between the flow of the second molten glass  231  and the forming body  200  before confluence of the flows of the second molten glass  231  with the flows of the first molten glass  211  flowing out of the first slot  220  and second slot  222 . 
     The first vertical wall  250  may be positioned at the first side  206  of the forming body  200  and may extend generally vertically (i.e., in the +/−Z direction of the coordinate axis of  FIG. 4 ) between the first conduit  210  to the second conduit  230 . The first vertical wall  250  may be coupled to the outer surface  234  of the second conduit wall  232  proximate a point at which a vertical plane (i.e., a plane in the X-Z plane of the coordinate axis in  FIG. 4 ) is tangent to the outer surface  234  of the second conduit wall  232  at the first side  206  of the forming body  200 . In some embodiments in which the second conduit  230  has two slots, the first vertical wall  250  may be coupled to the outer surface  234  of the second conduit wall  232  proximate a first slot  241  ( FIG. 8B ) in the second conduit wall  232 . The other end of the first vertical wall  250  may be coupled to the outer surface  214  of the first conduit wall  212  proximate the first slot  220  in the first conduit wall  212 . In some embodiments, the first vertical wall  250  may be coupled to a side of the conduit support  252  at a first side  206  of the forming body  200 . As such, the first vertical wall  250  may be at least partially or fully supported by the conduit support  252 . In other embodiments, the first vertical wall  250  may be spaced apart from the conduit support  252  so that the first vertical wall  250  does not contact the conduit support  252 . 
     The second vertical wall  260  may be positioned at a second side  208  of the forming body  200  and may extend generally vertically (i.e., in the +/−Z direction of the coordinate axis of  FIG. 4 ) between the first conduit  210  and the second conduit  230 . The second vertical wall  260  may be coupled to the outer surface  234  of the second conduit wall  232  proximate a point at which a vertical plane (i.e., a plane in the X-Z plane of the coordinate axis in  FIG. 4 ) is tangent to the outer surface  234  of the second conduit wall  232  at the second side  208  of the forming body  200 . In some embodiments in which the second conduit  230  has two slots, the second vertical wall  260  may be coupled to the outer surface  234  of the second conduit wall  232  proximate the second slot  242  ( FIG. 8B ) in the second conduit wall  232 . The other end of the second vertical wall  260  may be coupled to the outer surface  214  of the first conduit wall  212  proximate the second slot  222  in the first conduit wall  212 . In some embodiments, the second vertical wall  260  may be coupled to a side of the conduit support  252  at the second side  208  of the forming body  200 . As such, the second vertical wall  260  may be at least partially or fully supported by the conduit support  252 . In other embodiments, the second vertical wall  260  may be spaced apart from the conduit support  252  so that the second vertical wall  260  does not contact the conduit support  252 . 
     The first vertical wall  250 , the second vertical wall  260 , or both, may be configured so that flows of a second molten glass  231  from the second conduit  230  can maintain contact with the forming body  200  until contacting the flows of the first molten glass  211  from the first conduit  210 . In some embodiments, the first vertical wall  250 , the second vertical wall  260 , or both, may be configured so that the flows of the second molten glass  231  from the second conduit  230  do not free fall over a distance between the second conduit  230  and the first conduit  210 . When the first conduit  210  and the second conduit  230  are the same shape and size (e.g., have the same outer diameter), the first vertical wall  250  and the second vertical wall  260  may extend vertically (i.e., in the +/−Z direction of the coordinate axis of  FIG. 4 ). When the first conduit  210  and the second conduit  230  are different shapes and/or sizes (e.g., different outside diameters), the first vertical wall  250 , the second vertical wall  260 , or both, may not be perfectly vertical, but may be sloped between the first conduit  210  and the second conduit  230 . For example, in some embodiments, the second conduit  230  may be smaller in diameter than the first conduit  210  such that the first vertical wall  250 , the second vertical wall  260 , or both, may extend at an angle from first conduit wall  212  to the second conduit wall  232 . 
     The first vertical wall  250 , the second vertical wall  260 , or both, may be constructed of a refractory metal, such as but not limited to, platinum, platinum-alloy, or other refractory metal or metal alloy. The first vertical wall  250 , the second vertical wall  260 , or both, may be the same material as the first conduit wall  212  and the second conduit wall  232 . In some embodiments, the first conduit wall  212 , the second conduit wall  232 , the first vertical wall  250 , and the second vertical wall  260  may include platinum or a platinum alloy. In some embodiments, the first conduit wall  212 , the second conduit wall  232 , the first vertical wall  250 , and the second vertical wall  260  may consist of or consist essentially of platinum or a platinum alloy. 
     Referring to  FIG. 4 , the forming body  200  may include a forming wedge  280  comprising a forming surface support  281 , a first outer wall  284  providing the first forming surface  270 , and a second outer wall  286  providing the second forming surface  272 . The first forming surface  270  and the second forming surface  272  may extend from the outer surface  214  of the first conduit wall  212  and may converge at the root  274  of the forming body  200 . The first forming surface  270  and the second forming surface  272  extend from the outer surface  214  of the first conduit wall  212  in a vertically downward direction (i.e., the −Z direction of the coordinate axes in  FIG. 4 ) and converge towards one another, joining at the root  274  of the forming body  200 . Accordingly, it should be understood that the first forming surface  270  and the second forming surface  272  may, in some embodiments, form a shape resembling an inverted triangle (isosceles or equilateral) extending from the first conduit  210  of the forming body  200  with the root  274  forming the lower-most vertex of the triangle in the vertically downward direction. The draw plane P generally bisects the root  274  in the +/−Y directions of the coordinate axes depicted in  FIG. 4  and extends in the vertically downward direction and in the +/−X directions from the inlet end  217  to the compression end  218  of the first conduit  210  of the forming body  200 . 
     The forming surface support  281  may be disposed below the first conduit  210  and between the first forming surface  270  on the first side  206  of the forming body  200  and the second forming surface  272  on the second side  208  of the forming body  200 . The forming surface support  281  may support the first conduit  210 , may provide shape to the first forming surface  270  and the second forming surface  272 , and may provide support to the root  274 . The forming surface support  281  may include a first conduit support surface  282  configured to support a bottom portion of the first conduit wall  212 , which may be disposed vertically above (i.e., in the +Z direction of the coordinate axis of  FIG. 4 ) the forming surface support  281 . In some embodiments, the first conduit support surface  282  may have a shape conforming to at least a portion of a contour of the outer surface  214  of the first conduit wall  212  in the lower portion of the first conduit  210 . In some embodiments, the first conduit support surface  282  may include one or a plurality of support beams (not shown) shaped to support at least a portion of the lower portion of the first conduit  210 . The first conduit support surface  282  may support from 25% to 80% of the lower portion of the outer surface  214  of the first conduit wall  212 . The first conduit support surface  282  may support the weight of the first conduit  210  and second conduit  230  during operation of the forming body  200 . The first conduit support surface  282  may be operable to reduce or prevent deformation of the first conduit  210  in a vertical direction (e.g., in the −Z direction of the coordinate axis in  FIG. 4 ) and/or in a horizontal direction (i.e., in the +/−Y direction of the coordinate axis in  FIG. 4 ) during formation of the continuous laminate glass ribbon  102 . 
     The forming surface support  281  may be constructed of a support material capable of withstanding the temperatures experienced during formation of the continuous laminate glass ribbon  102  without deforming or experiencing creep. The forming surface support  281  may include a support material that is the same or different from the support material of the conduit support  252 , previously described herein. In some embodiments, the forming surface support  281  can be constructed from a support material having a creep rate from 1×10-12 per second (s−1) to 1×10-14 s−1 under a pressure of from 1 MPa to 5 MPa and ata temperature of 1400° C. In some embodiments, the forming surface support  281  may be constructed of a refractory material, such as, but limited to, one or more refractory metals, ceramic materials, or other refractory materials. In some embodiments, the forming surface support  281  may include a ceramic material, such as, but not limited to, zircon (e.g., zirconium silicate), low creep zircon, silicon carbide, xenotime, alumina based refractory ceramics, or combinations of these. In some embodiments, the forming surface support  281  may include a support material that is porous. The forming surface support  281  can withstand creep under high stress and temperature to enable maintenance of the position and shape of the first conduit wall  212  during formation of the continuous laminate glass ribbon  102 . 
     In some embodiments, the refractory material of the forming surface support  281  may be incompatible for physical contact with the refractory metal of the first conduit wall  212 , the first outer wall  284  of the forming wedge  280 , or the second outer wall  286  of the forming wedge  280 . For example, in some embodiments, the first conduit wall  212 , the first outer wall  284 , and/or the second outer wall  286  may include platinum (e.g. platinum or platinum alloy), and the forming surface support  281  may include silicon carbide, which may corrode or otherwise chemically react when contacted with platinum. In some embodiments, the forming surface support  281  may include a layer of an intermediate material (not shown) disposed between the first conduit support surface  282  and the first conduit  210 . The intermediate material may also be disposed between the forming surface support  281  and the first outer wall  284  and second outer wall  286 . The intermediate material may be operable to separate the refractory material of the forming surface support  281  from the platinum containing metal or other refractory metal of the first conduit wall  212 , first outer wall  284 , and/or the second outer wall  286 . 
     In some embodiments, the forming wedge  280  may include a forming wedge vacuum tube  288  in fluid communication with the support material of the forming surface support  281 . The forming wedge vacuum tube  288  may be fluidly coupled to a vacuum system (not shown), such as a vacuum pump or Venturi system. The vacuum system may be operable to create a vacuum within the forming wedge vacuum tube  288  and within the support material of the forming surface support  281 . 
     The forming wedge  280  may further include the first outer wall  284  coupled to an outer surface of the forming surface support  281  at the first side  206  of the forming body  200 . The first outer wall  284  may extend from the first conduit outer wall  212  to the root  274 . The first outer wall  284  may be coupled to the first conduit outer wall  212  proximate the first slot  220 . The first outer wall  284  may provide the first forming surface  270  extending from the first slot  220  to the root  274  on the first side  206  of the forming body  200 . The forming wedge  280  may further include the second outer wall  286  coupled to an outer surface of the forming surface support  281  at the second side  208  of the forming body  200 . The second outer wall  286  may be disposed on a side of the forming surface support  281  opposite the first outer wall  284 . The second outer wall  286  may extend from the first conduit outer wall  212  to the root  274 . The second outer wall  286  may be coupled to the first conduit outer wall  212  proximate the second slot  222 . The second outer wall  286  may provide the second forming surface  272  extending from the second slot  222  to the root  274  on the second side  208  of the forming body  200 . 
     The first outer wall  284  and/or the second outer wall  286  may be constructed of a refractory metal capable of withstanding the temperatures experienced during formation of the continuous laminate glass ribbon  102  without degrading or reacting with the constituents of the first molten glass  211  or the second molten glass  231 . The refractory metal may be platinum or a platinum-containing metal such as but not limited to platinum-rhodium, platinum-iridium and combinations thereof. Such refractory metals may also include molybdenum, palladium, rhenium, tantalum, titanium, tungsten, ruthenium, osmium, zirconium, and alloys thereof and/or zirconium dioxide. In some embodiments, the first conduit wall  212 , the second conduit wall  232 , or both, may be platinum or a platinum-alloy. 
     Referring to  FIG. 3 , the forming bodies  200  may include side dams  290  to control the flows of the first molten glass  211  and the second molten glass  231  down the outer surfaces of the forming body  200 . The side dams  290  can be made with an angle to vertical configured to accelerate the initial wetting, reduce the start-up time, and control lateral flow attenuation on the negatively inclined surface of the forming body  200 . In some embodiments, the angle of the side dams  290  can be from 0 degrees to 3 degrees. The forming bodies  200  disclosed herein may also include two pier blocks  292  configured to support the first conduit  210  and the second conduit  230  simultaneously. The pier blocks  292  may be constructed of a material, such as a ceramic material or other refractory material, that is capable of withstanding the thermal gradients and high operating temperatures experienced during formation of the continuous laminate glass ribbon  102 . In some embodiments, the pier blocks  292  may be mullite. 
     Referring to  FIGS. 4 and 5 , general operation of the forming bodies  200  of the present disclosure will now be described. The first molten glass  211  may be produced in the first molten glass system  110  ( FIG. 1 ), and the second molten glass  231  may be produced in the second molten glass system  150  ( FIG. 1 ), as previously described herein. The first molten glass  211  may be passed from the first delivery vessel  136  ( FIG. 1 ) to the first inlet  202  through the first downcomer  138 , which is coupled to the first delivery vessel  136  such that a free surface of the first molten glass  211  is not created between the first delivery vessel  136  and the first downcomer  138 . The second molten glass  231  may be passed from the second delivery vessel  176  ( FIG. 1 ) to the second inlet  204  through the second downcomer  178 , which is coupled to the second delivery vessel  176  such that a free surface of the second molten glass  231  is not created between the second delivery vessel  176  and the second downcomer  178 . The first downcomer  138  and the second downcomer  178  may each include one or a plurality of heat exchangers (not shown) for controlling the temperature of the first molten glass  211  and the second molten glass  231  passing through the first downcomer  138  and second downcomer  178 , respectively. 
     As previously discussed, the forming body  200  comprising a first conduit  210  and a second conduit  230 , as described herein, may enable the glass flow rate and viscosity to be adjusted independently for each of the first molten glass  211  and the second molten glass  231 . This independent control of the glass flow rate and viscosity may result from changing pressures of the first molten glass  211  and second molten glass  231  at the first inlet  202  and the second inlet  204 , respectively. The pressure of the first molten glass  211  at the first inlet  202  of the forming body  200  may be adjusted by manipulating the glass temperature of the first molten glass  211  at one or more positions along the first downcomer  138 . The pressure of the second molten glass  231  at the second inlet  202  of the forming body  200  may be adjusted by manipulating the glass temperature of the second molten glass  231  at one or more positions along the second downcomer  178 . Thus, controlling the temperature of the molten glass in the downcomers may control the pressure at the inlet to the forming body, which may enable the glass flow rate and glass viscosity to be varied independently for each molten glass flow. 
     Referring still to  FIGS. 4 and 5 , the first molten glass  211  may be passed from the first molten glass system  110  to the first conduit  210  through the first inlet  202  of the forming body  200 . The first molten glass  211  may flow through the first conduit  210  from the first conduit inlet end  217  to the first conduit compression end  218 . Referring to  FIG. 4 , the first molten glass  211  may flow through the first slot  220  in the first conduit wall  212  and may merge into a flow of the first molten glass  211  flowing down the first side  206  of the forming body  200 . The flow of the first molten glass  211  through the first slot  220  may flow generally downward (i.e., in the −Z direction of the coordinate axis of  FIG. 4 ) along the first forming surface  270  to the root  274 . In some embodiments, the first molten glass  211  may also flow through a second slot  222  in the first conduit wall  210  and may merge with a second flow of the first molten glass  211  flowing down the second side  208  or the forming body  200 . The flow of the first molten glass  211  through the second slot  222  may flow generally downward along the second forming surface  272  to the root  274 . At the root  274 , the two flows of the first molten glass  211  may fuse together to form a single molten glass layer, which may be a core layer  104  of the continuous laminate glass ribbon  102 . 
     The second molten glass  231  may be passed from the second molten glass system  150  to the second conduit  230  through the second inlet  204  of the forming body  200 . The second molten glass  231  may flow through the second conduit  230  from the second conduit inlet end  237  to the second conduit compression end  238 . In some embodiments, the flow of the second molten glass  231  through the second conduit  230  may be in a direction counter to the flow direction of the first molten glass  211  through the first conduit  210 . Referring to  FIG. 4 , the second molten glass  231  may flow through the at least one slot  240  in the second conduit wall  232 . Upon exiting the slot  240 , the second molten glass  231  may merge into two flows of the second molten glass  231  flowing over the outer surface  234  of the second conduit wall  232 ; one flow of the second molten glass  231  flowing down the first side  206  of the forming body  200  and the other flow of the second molten glass  231  flowing down the second side  208  of the forming body  200 . The two flows of the second molten glass  231  may flow downward (i.e., in the −Z direction of the coordinate axis in  FIG. 4 ) along the first vertical wall  250  and the second vertical wall  260 , respectively. Proximate the first slot  220  and the second slot  222 , respectively, the two flows of the second molten glass  231  may each contact an outer surface of a flow of the first molten glass  211 . Upon contact, the flow of the second molten glass  231  may fuse to the flow of the first molten glass  211 . The second molten glass  231  may flow with the first molten glass  211  down the first forming surface  270  and second forming surface  272  to the root  274 . The flows of the second molten glass  231  may form clad layers  106  of the continuous laminate glass ribbon  102 . In some embodiments, the core layer  104  of the first molten glass  211  may be disposed between the two clad layers  106  comprising the second molten glass  231 . 
     The continuous laminate glass ribbon  102  may be drawn from the root  274  by a pulling device (not shown) and may be passed to one or more downstream processes (not shown) for further processing the continuous laminate glass ribbon  102 . For example, the continuous laminate glass ribbon  102  may be passed through an annealing furnace to anneal the continuous laminate glass ribbon  102 . The continuous laminate glass ribbon  102  may also be passed to a cutting and separating operation in which the continuous laminate glass ribbon  102  is separated into a plurality of laminate glass sheets. 
     Referring now to  FIGS. 8A-8D , various slot positions and configurations may be implemented in the forming bodies  200  described herein to produce different continuous laminate glass ribbons  102 . Referring to  FIG. 8A , as previously discussed, in some embodiments, the first conduit  210  may include the first slot  220  on the first side  206  of the forming body  200  and the second slot  222  on the second side  208  of the forming body  200 , and the second conduit  230  may include a single slot  240 . The slot  240  of the second conduit  230  may extend through the second conduit wall  232  at a uppermost portion of the second conduit wall  232  so that molten glass flowing through the at least one slot  240  in the second conduit wall  232  flows down the first side  206  and the second side  208  of the forming body  200 . The second conduit  230  having a single slot  240  may allow for an overflow region on the topmost surface  244  of the second conduit wall  232  where the gravity and surface tension of the second molten glass  231  can smooth out small perturbations of the glass enabling a fusion-quality pristine surface. 
     For continuous laminate glass ribbons  102  that are symmetrical, the single slot  240  may deliver the same amount of the second molten glass  231  to the first side  206  and second side  208  of the forming body  200 , which may form clad layers  106  having the same thickness, independent of small process variations. These small process variations, such as variations in temperatures at different points along the outer surface  234  of the second conduit  230 , cross-tilt of the forming body  200 , or other process variations, may result in differences in thickness between the two clad layers formed from the flows of the second molten glass  231  down each side of the forming body  200 . The shape of the outer surface  234  of the topmost portion of the second conduit wall  230  may have an impact on the sensitivity of the second conduit wall  230  to these small process variations. 
     Referring to  FIG. 9 , in some embodiments, the topmost surface  244  of the second conduit  230  may have a rounded or semi-circular shape. In these embodiments, the second molten glass  231  may pass through the slot  240  in the topmost surface  244  and merge into two separate flows, each of which may flow down the curved contour of the topmost surface  244 . Referring now to  FIG. 10 , in some embodiments, the topmost surface  244  of the second conduit  230  may be more angular or square-shaped having a flat portion on either side of the slot  240  and a sharper corner at each side of the second conduit  230 . In these embodiments, the second molten glass  231  may pass through the slot  240  and merge with the glass flows that propagate laterally from either side of the slot  240 . The two separate glass flows each travel laterally along the topmost surface  244 , which is generally flat, and then over the corner to travel down the first side  206  and second side  208  of the forming body  200 . Referring to  FIG. 11 , in still other embodiments, the topmost surface  244  of the second conduit  230  may include a trough  246  defined between two weirs, which resembles the geometry of an overflow isopipe. In these embodiments, the second molten glass  231  may pass through the slot  240  up into the trough  246 . The second molten glass  231  may fill the trough and overflow the two weirs to flow down the first side  206  and second side  208  of the forming body  200 . 
     Each of the shapes of the topmost surface  244  of the second conduit  230  in  FIGS. 9, 10, and 11  may have a different sensitivity to small process variations, such as cross-tilt for example. Referring to  FIG. 12 , the sensitivity of each of the second conduits  230  in  FIGS. 9, 10, and 11  to cross-tilt of the forming body  200  is graphically depicted. Cross-tilt of the forming body refers to tilting or rolling of the second conduit relative to an axis parallel to the x-axis in the figures (e.g., rotation or pivoting of the second conduit  230  of the forming body  200  in  FIG. 3  relative to an axis parallel with the X axis of  FIG. 3 ).  FIG. 12  depicts the ratio of the right side flow (first side  206 ) divided by the left side flow (second side  208 ) as a function of tilt angle a, which is an angle by which the second conduits  230  in  FIGS. 9-11  are tilted towards the right side in the figures. Reference number  1302  corresponds to the sensitivity of the second conduit  230  of  FIG. 9  having a rounded topmost surface  244 , reference number  1304  corresponds to the sensitivity of the second conduit  230  of  FIG. 10  having a flat topmost surface  244 , and reference number  1306  corresponds to the sensitivity of the second conduit  230  of  FIG. 11  having the trough  246 . At a tilt angle a of zero, the ratio of right side flow to left side flow is equal to  1  for each of the second conduits in  FIGS. 9-11 . As shown in  FIG. 12 , the rounded contour of the second conduit  230  in  FIG. 9  (ref  1302 ) provides the least sensitivity to cross-tilt of the second conduit  230 , as shown by the lesser slope of line  1302  compared to the slopes of lines  1304  and  1306 . In other words, in response to a unit change in the cross-tilt angle α of the second conduit  230 , the rounded contour of the second conduit in  FIG. 9  results in the least change in the distribution of the second molten glass  231  between the right side and the left side of the forming body  200  compared to the shapes in  FIGS. 10 and 11 . Having a more rounded contour to the topmost surface  244  of the second conduit wall  232  of the second conduit  230  may, therefore, be less sensitive to small process variations, such as cross-tilt, temperature variations or other variations, compared to topmost surfaces  244  that are flat or have a trough  246 . 
     Referring now to  FIG. 8B , in some embodiments, the first conduit  210  may include the first slot  220  on the first side  206  of the forming body  200  and the second slot  222  on the second side  208  of the forming body  200 . Additionally, the second conduit  230  may include a first slot  241  extending through the second conduit wall  232  at the first side  206  of the forming body  200  and a second slot  242  extending through the second conduit wall  232  at the second side  208  of the forming body  200 . In some embodiments, the first slot  241  may have a different slot width W S  profile than the second slot  242 , which may enable different flow rates of the second molten glass  231  down the first side  206  and the second side  208  of the forming body  200 . This may enable a continuous laminate glass ribbon  102  to be formed having a first clad layer  105  and a second clad layer  107  having a thickness different from the first clad layer  105 . In some embodiments, the first slot  241  and the second slot  242  in the second conduit  230  may have the same slot width W S  profile so that the thickness of the first clad layer  105  is the same as the thickness of the second clad layer  107 . 
     Referring now to  FIG. 8C , in some embodiments, the first conduit  210  may include the first slot  220  and the second slot  222 , and the second conduit  230  may include the single slot  240  passing through the second conduit wall  232  proximate the first side  206  or the second side  208  of the forming body  200 . The forming body  200  of  FIG. 8C  may be operable to produce a continuous laminate glass ribbon  102  having two glass layers, such as a first layer  108  and a second layer  109 . The relative thicknesses of the first layer  108  and the second layer  109  may be modified by changing the slot width W S  profile of the slot  240 , the first slot  220 , or the second slot  222 . 
     Referring now to  FIG. 8D , in some embodiments, the first conduit  210  may include only a single slot, such as the first slot  220  or the second slot  222 , but not both, and the second conduit  230  may include the single slot  240  positioned at a side of the forming body opposite the single slot in the first conduit  210 . For example, in some embodiments, the first conduit  210  may include the first slot  220  extending through the first conduit wall  212  at the first side  206  of the forming body  200 , and the single slot  240  may extend through the second conduit wall  232  proximate the second side  208  of the forming body  200 . In this configuration, the first molten glass  211  passing through the first slot  220  in the first conduit  210  may travel downward along the first forming surface  270  to the root  274 , and the second molten glass  231  passing through the single slot  240  in the second conduit  230  flows downward (in the −Z direction of the coordinate axis in  FIG. 8D ) along the second vertical wall  260  and second forming surface  272  to the root  274 . At the root  274 , the flow of the second molten glass  231  may contact the flow of the first molten glass  211 . The second molten glass  231  and the first molten glass  211  may fuse together at the root  274  to produce the continuous laminate glass ribbon  102  having two glass layers, such as first glass layer  108  and second glass layer  109 . The relative thicknesses of the first glass layer  108  and the second glass layer  109  may be modified by changing the shape of the single slot  240  in the second conduit  230 , the shape of the slot (e.g., first slot  220  or second slot  222 ) in the first conduit  210 , or both. 
     Referring again to  FIGS. 6A and 6B , in some embodiments, the at least one slot  240  in the second conduit  230  may have the same slot length L S  as the first slot  220  and the second slot  222  in the first conduit  210 . In other embodiments, the at least one slot  240  in the second conduit  230  may have a slot length L S  different from the slot length L S  of the first slot  220  and second slot  222  in the first conduit  210 . For example, in some embodiments, the slot  240  in the second conduit  230  may have a slot length L S  that is greater than the slot length L S  of the first slot  220  and second slot  222  in the first conduit  210 , which may produce a continuous laminate glass ribbon  102  in which the core glass layer  104  ( FIG. 4 ) is completely enclosed by the clad glass layers  106  ( FIG. 4 ). Alternatively, in some embodiments, the slot  240  in the second conduit  230  may have a slot length L S  that is less than the slot length L S  of the first slot  220  and second slot  222  in the first conduit  210 , which may produce a continuous laminate glass ribbon  102  in which only a center portion of the continuous laminate glass ribbon  102  will be a laminate. In some embodiments, a continuous glass ribbon may be formed to have both laminated sections and single layer non-laminated sections. Alternating sections of laminate and non-laminate regions in the glass ribbon can be accomplished by using non-continuous perforated slots for the slot  240  in the second conduit  230  or for the first slot  220  and second slot  222  in the first conduit  210 . Perforated slots are previously discussed herein and further information on perforated slots can be found in co-pending U.S. Provisional Patent Application No. 62/717,173, filed on Aug. 10, 2018, the entire contents of which were previously incorporated by reference herein in their entirety. 
     Referring now to  FIG. 13 , the forming bodies disclosed herein, such as forming body  300 , can be adapted to add additional glass layers to the continuous laminate glass ribbon  102  by including one or a plurality of supplemental conduits  310 . In some embodiments, the forming body  300  may include at least one supplemental conduit  310  disposed above (i.e., in the +Z direction of the coordinate axis of  FIG. 13 ) and vertically aligned with the first conduit  210  and the second conduit  230 . The forming body  300  may include 1, 2, 3, 4, or more than 4 supplemental conduits  310  for forming a continuous laminate glass ribbon  102  having a plurality of different glass layers. The supplemental conduit  310  may include a supplemental conduit wall  312  having an interior surface  313  defining a supplemental region  316 . The supplemental conduit  310  may further include at least one slot  320  extending through the supplemental conduit wall  312 . The at least one slot  320  of the supplemental conduit  310  may have a longest dimension (e.g., slot length L S ) aligned with a direction of flow of a supplemental molten glass  311  through the supplemental conduit  310 . Although shown as having a single slot  320 , in some embodiments, the supplemental conduit  310  may include a first slot proximate the first side  206  of the forming body  300  and a second slot proximate the second side  208  of the forming body  300 . The supplemental conduit  310  may have any of the other features, properties, or characteristics previously described herein in relation to the first conduit  210  and/or the second conduit  230 . 
     The forming body  300  may also include a plurality of supplemental vertical walls, such as a first supplemental vertical wall  350  and a second supplemental vertical wall  360 , extending vertically (i.e., in the +/−Z direction of the coordinate axis of  FIG. 4 ) between the outer surface  234  of the second conduit  230  and an outer surface  314  of the at least one supplemental conduit  310 . An outer surface  351  of the first supplemental vertical wall  350  and an outer surface  361  of the second supplemental vertical wall  360  may provide continuous surfaces over which the flows of the supplemental molten glass  311  from the supplemental conduit  310  can flow from the outer surface  314  of the supplemental conduit wall  312  into contact with the second molten glass  231  from the second conduit  230  and/or the first molten glass  211  from the first conduit  210 . Thus, the first supplemental vertical wall  350  and the second supplemental vertical wall  360  may eliminate any gaps or air pockets between the flow of the supplemental molten glass  311  and the forming body  300  before confluence of the flows of supplemental molten glass  311  with the flows of the first molten glass  211  and/or second molten glass  231 . 
     The first supplemental vertical wall  350  and second supplemental vertical wall  360  may have any of the other features, properties, or characteristics previously described herein for the first vertical wall  250  and the second vertical wall  260 , respectively. The forming body  300  may additionally include a supplemental conduit support  352  disposed between the second conduit  230  and the supplemental conduit  310 . The supplemental conduit support  352  may have an upper surface  354  configured to support the supplemental conduit  310  and a lower surface  356  configured to support the upper portion of the second conduit  230 . The supplemental conduit support  352  may have any of the other features, properties, or characteristics previously described herein for the conduit support  252 . 
     The supplemental conduit  310  may be fluidly coupled to a supplemental molten glass system (not shown) for delivery the supplemental molten glass  311  to the supplemental conduit  310 . Operation of the supplemental conduit  310  may be similar to operation of the first conduit  210  and second conduit  230 , which was previously described herein. In some embodiment, the forming body  300  may include a plurality of supplemental conduits  310  and a plurality of supplemental vertical walls (e.g., a plurality of first supplemental vertical walls  350  and second supplemental vertical walls  360 ), each of which extending between two of the plurality of supplemental conduits  310  or between one of the supplemental conduits  310  and the second conduit  230 . Based on the previous description of the first conduit  210  and the second conduit  230 , it is understood that various configurations the supplemental slots  320  in the supplemental conduits  310  are possible for providing a wide range of different continuous laminate glass ribbons  102 . These various slot configurations for the supplemental slots  320  in the supplemental conduits  310  are considered to be covered by present disclosure. 
     Referring to  FIG. 14A , in some embodiments, the first vertical wall outer surface  251  may be vertically aligned (e.g., aligned in the +/−Z direction of the coordinate axis of  FIGS. 14A and 14B ) with the outer surface  214  of the first conduit wall  212  at the first slot  220 . Additionally, on the second side  208  of the forming body  200 , the second vertical wall outer surface  261  may be vertically aligned with the outer surface  214  of the first conduit wall  212  at the second slot  222 . When the first vertical wall outer surface  251  and the second vertical wall outer surface  261  are vertically aligned with the outer surface  214  of the first conduit wall  212  at the first slot  220  and the second slot  222 , respectively, the first molten glass  211  flowing out from the first slot  220  and/or the second slot  222  may cause the flow of the second molten glass  231  to deform outward from the forming body  200  at the confluence of the second molten glass  231  and the first molten glass  211 . This outward deformation of the second molten glass  231  may cause defects in the core or clad glass layers. For example, the second molten glass  231  may exert a pressure on the flow of the first molten glass  211  through contact of the flow of the second molten glass  231  with the first molten glass  211  at the confluence. 
     Referring to  FIG. 14B , in some embodiments, the first vertical wall outer surface  251  may be vertically offset from the outer surface  214  of the first conduit wall  212 , which may provide space for the first molten glass  211  to flow out of the first slot  220  with minimal deformation of the flow of the second molten glass  231  at the confluence. The vertical offset may provide smooth and stable confluence of the first molten glass  211  and second molten glass  231  proximate the first slot  220  and/or the second slot  222 . The vertical offset may reduce the force of the contact between the flow of the second molten glass  231  and the flow of the first molten glass  211  at the confluence of the second molten glass  231  with the first molten glass  211 . In some embodiments, the first vertical wall outer surface  251  may be spaced horizontally outward relative to the outer surface  214  of the first conduit wall  212  at the first slot  220  by an offset distance  380  to form the vertical offset between the first vertical wall outer surface  251  and the outer surface  214  of the first conduit wall  212 . The second vertical wall outer surface  261  may also be vertically offset from the outer surface  214  of the first conduit wall  212  at the second slot  222 . In some embodiments, the second vertical wall outer surface  261  may be spaced horizontally outward relative to the outer surface  214  of the first conduit wall  212  at the second slot  222  by an offset distance  380  to form the vertical offset between the second vertical wall outer surface  261  and the outer surface  214  of the first conduit wall  212 . The offset distance  380  may be less than or equal to a thickness of a flow of the first molten glass  211  down the first forming surface  270  or the second forming surface  272 . In some embodiments the offset distance  380  may be less than or equal to half the thickness of the core glass layer  104  produced by the forming body  200  of  FIG. 4 . The vertical offset may be configured so that deformation of the second molten glass  231  flow from the second conduit  230  can be reduced at the confluence. 
     The present disclosure focuses on aspects of the forming body  200 ,  300 ; however, it is understood that the glass forming apparatus  100  may include various other components that aid in forming continuous laminate glass ribbons  102 . For example, in some embodiments, the forming body  200 ,  300  may include a plurality of stacked and independently controlled furnaces surrounding the forming body  200 ,  300  to provide a controlled thermal environment. The plurality of furnaces may be referred to as a thermal muffle (not shown). The thermal muffle comprising a plurality of stacked and independently controlled furnaces may enable control of the delivery viscosities of the first molten glass  211  passing through the first slot  220  and the second slot  222  in the first conduit  210  and the second molten glass  231  passing through the at least one slot  240  in the second conduit  230 . The thermal muffle may also enable control of the cooling curve to the root  274  and/or draw viscosity of the continuous laminate glass ribbon  102  at the exit of the thermal muffle. The thermal muffle may have various heating elements and internal features to facilitate heat transfer within the thermal muffle. 
     Below the thermal muffle, the glass forming apparatus  100  may additionally include edge-pulling devices to stabilize width and position of the continuous laminate glass ribbon  102  as it exits the muffle. The continuous laminate glass ribbon  102  may then be drawn through an annealing furnace to cool the glass temperature at an acceptable rate from exit viscosity to a temperature below the strain point. Finally, a pulling and cutting machine may be used to apply the downward pulling velocity to the glass, stabilize the glass position, and separate glass sheets from the end of the continuous laminate glass ribbon  102 . 
     Referring again to  FIGS. 4 and 5 , a method of forming a continuous laminate glass ribbon  102  having a plurality of glass layers may include flowing the first molten glass  211  into the first conduit  210  in the forming body  200 ,  300 . The first conduit  210  may include a first conduit wall  212  having an interior surface  213  defining a first region  216  and at least one slot (e.g., first slot  220  and/or second slot  222 ) extending through the first conduit wall  212  and in fluid communication with the first region  216 . The at least one slot of the first conduit  210  may have a longest dimension (e.g., slot length L S ) aligned with a direction of flow of the first molten glass  211  through the first conduit  210 . The method may further include passing the first molten glass  211  through the at least one slot in the first conduit wall  212  to merge with a first glass flow on a first side  206  of the forming body  200 ,  300 , a second side  208  of the forming body  200 ,  300 , or both. The method may further include flowing a second molten glass  231  into the second conduit  230  in the forming body  200 ,  300 . The second conduit  230  may be positioned above and vertically aligned with (e.g., in the +/−Z direction of the coordinate axis of the figures) the first conduit  210  and comprising the second conduit wall  232  having the interior surface  233  defining a second region  236  and at least one slot  240  extending through the second conduit wall  232  and in fluid communication with the second region  236 . The at least one slot  240  of the second conduit  230  may have a longest dimension (e.g., slot length L S ) aligned with a direction of flow of the second molten glass  231  through the second conduit  230 . The method may further include passing the second molten glass  231  through the at least one slot  240  in the second conduit wall  232  to merge with a second glass flow on the first side  206  of the forming body  200 ,  300 , the second side  208  of the forming body  200 ,  300 , or both. The method may further include merging the second glass flow of the second molten glass  231  with the first glass flow of the first molten glass  211  to form the continuous laminate glass ribbon  102  having a plurality of molten glass layers fused together. The method may further include drawing the continuous laminate glass ribbon  102  downward (i.e., in the −Z direction of the coordinate axis of the figures) from the root  274  of the forming body  200 . 
     In some embodiment, the method may include merging the second glass flow with the first glass flow at the root  274  of the forming body  200 ,  300 . In other embodiments, the method may include merging the second glass flow of the second molten glass  231  with the first glass flow of the first molten glass  211  proximate the at least one slot (e.g., first slot  220  and/or second slot  222 ) in the first conduit wall  212  on the first side  206  of the forming body  200 ,  300 , the second side  208  of the forming body  200 ,  300 , or both. The first molten glass  211  may have a glass composition different from a glass composition of the second molten glass  231 . In some embodiments, the first glass flow of the first molten glass  211  may form a core glass (e.g., core glass layer  104 ) and the second glass flow of the second molten glass  231  may form a clad glass (e.g., clad glass layer  106 ). 
     In some embodiments, the first conduit  210  may include the first slot  220  extending through the first conduit wall  212  at the first side  206  of the forming body  200 ,  300  and the second slot  222  extending through the first conduit wall  212  at the second side  208  of the forming body  200 ,  300 . The method may further include passing the first molten glass  211  through the first slot  220  to merge with a first portion of the first glass flow on the first side  206  of the forming body  200 ,  300 , passing the first molten glass  211  through the second slot  222  to merge with a second portion of first glass flow on the second side  208  of the forming body  200 ,  300 , and merging the first portion of the first glass flow and the second portion of the first glass flow at the root  274  to form a fused layer of molten glass in a core glass layer  104  of the continuous laminate glass ribbon  102 . 
     In some embodiments, the method may further include annealing the continuous laminate glass ribbon  102 . In some embodiments, the method may further include separating the laminated glass ribbon into a plurality of laminated glass sheets. 
     In some embodiment, the methods of forming a continuous laminate glass ribbon  102  disclosed herein may further include flowing a third molten glass  311  into a third conduit  310  in the forming body  200 ,  300 . The third conduit  310  may be positioned above and vertically aligned with the first conduit  210  and second conduit  230 . The third conduit  310  may include a third conduit wall  312  having an interior surface  313  defining a third region  316  and at least one slot  320  extending through the third conduit wall  312  and in fluid communication with the third region  316 . The at least one slot  320  of the third conduit  310  may have a longest dimension (e.g., slot length L S ) aligned with a direction of flow of the third molten glass  311  through the third conduit  310 . The method may further include passing the third molten glass  311  through the at least one slot  320  in the third conduit wall  312  to merge with a third glass flow on a first side  208  of the forming body  200 ,  300 , a second side  208  of the forming body  200 ,  300 , or both. The method may further include merging the third glass flow with the second glass flow, the first gas flow, or both. 
     The glass forming apparatus  100 , forming bodies  200 ,  300 , and methods of the disclosure can provide a continuous laminate glass ribbon  102  having a plurality of glass layers, such as 2, 3, 4, 5, 6, or more than 6 glass layers. The continuous laminate glass ribbon  102  may be subsequently divided into laminate glass sheets. In some embodiments, the laminate glass sheets may be provided with four edges forming a parallelogram such as a rectangle (e.g., square), trapezoidal or other shape. In further embodiments, the laminate glass sheets may be a round, oblong, or elliptical glass sheet with one continuous edge. Other laminate glass sheets having two, three, five, etc. curved and/or straight edges may also be provided and are contemplated as being within the scope of the present description. Laminate glass sheets of various sizes, including varying lengths, heights, and thicknesses, are also contemplated. In some embodiments, an average thickness of the laminate glass sheets can be various average thicknesses between oppositely facing major surfaces of the glass sheet. In some embodiments, the average thickness of the laminate glass sheet can be greater than 50 micrometers (μm), such as from about 50 μm to about 1 millimeter (mm), such as from about 100 μm to about 300 μm although other thicknesses may be provided in further embodiments. 
     The laminate glass sheets can be used in a wide range of display applications such as, but not limited to, liquid crystal displays (LCDs), electrophoretic displays (EPD), organic light emitting diode displays (OLEDs), and plasma display panels (PDPs). The laminate glass sheets can also be formed into glass articles that can be used in various application, including, but not limited to, cover glass or glass backplane applications in consumer or commercial electronic devices including, for example, LCD and LED displays as previously discussed, computer monitors, and automated teller machines (ATMs); for touch screen or touch sensor applications, for portable electronic devices including, for example, mobile telephones, personal media players, and tablet computers; for integrated circuit applications including, for example, semiconductor wafers; for photovoltaic applications such as photovoltaic cells; for architectural glass applications; for automotive or vehicular glass applications; or for commercial or household appliance applications. In various embodiments, a consumer electronic device (e.g., smartphones, tablet computers, personal computers, ultrabooks, televisions, and cameras), an architectural glass, and/or an automotive glass comprises a laminated glass sheet as described herein. 
     Based on the foregoing, it should now be understood that the embodiments described herein relate to forming bodies for use in glass forming apparatuses for producing continuous laminate glass ribbons and laminate glass sheets. The forming bodies described herein may be constructed to produce a continuous laminate glass ribbon. The forming bodies may provide for smooth and stable confluence of the various molten glass streams to reduce flow instabilities and air entrapment that may lead to defects in the continuous laminate glass ribbons  102 . The forming bodies may also enable independent control of glass flow profiles and glass viscosities to broaden the range of combinations of glass compositions and thickness profiles able to be produced by the glass forming apparatus. 
     While various embodiments and techniques for producing continuous laminate glass ribbons have been described herein, it should be understood it is contemplated that each of these embodiments and techniques may be used separately or in conjunction with one or more embodiments and techniques. 
     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 claimed subject matter. Thus, it is intended that the specification cover the modifications and variations of the various embodiments described herein provided such modification and variations come within the scope of the appended claims and their equivalents.