EP4626835A1

EP4626835A1 - Apparatus and method for extracting heat during formation of glass ribbons

Info

Publication number: EP4626835A1
Application number: EP23822147.7A
Authority: EP
Inventors: Antoine Gaston Denis Bisson; Charles Thomas MCLAREN; Nicholas Ryan Wheeler
Original assignee: Corning Inc
Current assignee: Corning Inc
Priority date: 2022-11-28
Filing date: 2023-11-09
Publication date: 2025-10-08
Also published as: CN118084301A; TW202436247A; JP2025539376A; KR20250116704A; WO2024118204A1

Abstract

A glass forming apparatus is disclosed including a glass delivery device and a heat extraction assembly. The glass delivery device includes a slot block through which molten glass flows and is formed into a glass ribbon, and the slot block includes a plurality of channels formed therein. The heat extraction assembly includes an outer tube, an inner tube, a cooling fluid source, and an exhaust manifold. The outer tube includes a proximal end and a distal end connected to one of the plurality of channels. The inner tube extends within an outer lumen of the outer tube. The cooling fluid source is fluidly coupled to the inner tube to thereby supply a cooling fluid to an inner lumen of the inner tube. The exhaust manifold is fluidly coupled to an exhaust channel defined between the inner tube and the outer tube for exhausting the cooling fluid.

Description

APPARATUS AND METHOD FOR EXTRACTING HEAT DURING FORMATION OF GLASS RIBBONS

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of priority under 35 U.S.C. §119 of U.S. Provisional Application Serial No. 63/428174 filed on November 28, 2022, the content of which is relied upon and incorporated herein by reference in its entirety.

TECHNICAL FIELD

[0002] The present specification relates to glass manufacturing apparatuses and, more particularly, to glass manufacturing apparatuses with glass forming apparatuses comprising heat extraction assemblies.

BACKGROUND

[0003] Glass manufacturing apparatuses can include a variety of discrete components for melting, processing, and forming glass. For example, a typical glass manufacturing apparatus may include, among other components, a melter for melting a batch of glass constituent components to form a molten material (e.g., molten glass), a fining system for removing dissolved gasses from the molten glass, a mixing vessel for homogenizing the molten glass, and a forming apparatus for forming the molten glass into a desired shape (e.g., a ribbon, cylinders, tubes, etc.).

[0004] In the production of glass ribbons, which may be segmented into discrete glass sheets for use in display applications, including televisions, computer monitors, and hand-held devices, molten glass can be formed into a glass ribbon by flowing the molten glass into a glass forming apparatus, and drawing a glass ribbon from the glass forming apparatus. However, challenges may exist in producing glass ribbons with acceptable dimensional characteristics. For example, the glass ribbon may exhibit ribbon stability issues during forming, such as ribbon deflection (side-to-side ribbon walking) and sheet width variation.

[0005] Accordingly, a need exists for alternative designs for glass forming apparatuses that mitigate ribbon stability issues and thereby improve the quality of the resulting glass ribbon and glass sheets segmented therefrom. SUMMARY

[0006] A first aspect includes a glass forming apparatus comprising: a glass delivery device comprising a slot block through which molten glass flows and is formed into a glass ribbon as it exits a slot orifice of the slot block, the slot block comprising a vertical dimension corresponding with a flow direction of the molten glass, a width dimension orthogonal to the vertical dimension, and a thickness dimension orthogonal to the vertical dimension and the width dimension, and a plurality of channels formed therein at positions proximate to the slot orifice; and a heat extraction assembly comprising: an outer tube having a distal end and a proximal end, the distal end of the outer tube connected to one of the plurality of channels; an inner tube extending within an outer lumen of the outer tube, the inner tube having a distal end and a proximal end, and the inner tube positioned within the outer lumen of the outer tube such that the distal end of the inner tube is positioned proximate to the distal end of the outer tube; a cooling fluid source fluidly coupled to the inner tube to thereby supply a cooling fluid to an inner lumen of the inner tube; and an exhaust manifold fluidly coupled to the outer lumen of the outer tube for exhausting the cooling fluid from an exhaust channel defined between an inner surface of the outer tube and an outer surface of the inner tube.

[0007] A second aspect includes the glass forming apparatus of the first aspect, further comprising a housing defining an internal channel, wherein: the outer tube is connected to the housing such that the outer lumen of the outer tube is in fluid communication with the internal channel of the housing; the exhaust manifold is fluidly coupled to the internal channel of the housing such that an exhaust lumen of the exhaust manifold is in fluid communication with the internal channel of the housing; and the inner tube extends at least partially through the internal channel of the housing.

[0008] A third aspect includes the glass forming apparatus of any preceding aspect, wherein: the housing comprises a connector slideably positioned within the housing; the connector comprises an inner passageway; and the inner tube extends through the inner passageway of the connector and is coupled to the connector, whereby translating the connector relative to the housing adjusts a spacing between the distal end of the inner tube and the distal end of the outer tube.

[0009] A fourth aspect includes the glass forming apparatus of any preceding aspect, further comprising a set screw threadably inserted into the housing, the set screw for locking the connector to the housing and inhibiting sliding of the connector upon rotation of the set screw in a first direction.

[0010] A fifth aspect includes the glass forming apparatus of any preceding aspect, wherein the inner tube is threadably coupled to the connector, whereby rotation of the inner tube in the connector adjusts the spacing between the distal end of the inner tube and the distal end of the outer tube.

[0011] A sixth aspect includes the glass forming apparatus of any preceding aspect, further comprising an insulating insert provided within one or more of the plurality of channels, the insulating insert having at least one opening through which material of the slot block proximate to the slot orifice is exposed to enhance heat extraction from the material.

[0012] A seventh aspect includes the glass forming apparatus of any preceding aspect, wherein the at least one opening of the insulating insert faces a bottom side of the slot block through which the glass ribbon exits the slot orifice.

[0013] An eighth aspect includes the glass forming apparatus of any preceding aspect, further comprising: an exhaust temperature sensor operably coupled to the exhaust manifold for measuring an output temperature of cooling fluid in the exhaust manifold; and a cooling fluid temperature sensor operatively coupled to the cooling fluid source to measure an input temperature of the cooling fluid supplied to the inner tube.

[0014] A ninth aspect includes the glass forming apparatus of any preceding aspect, further comprising a controller operatively connected to the cooling fluid temperature sensor and the exhaust temperature sensor, the controller programmed to calculate heat extraction at the slot block based on the output temperature of the cooling fluid in the exhaust manifold and the input temperature of the cooling fluid supplied by the cooling fluid source.

[0015] A tenth aspect includes the glass forming apparatus of any preceding aspect, wherein the controller is operable to adjust a flow rate of cooling fluid supplied by the cooling fluid source based on the calculated heat extraction.

[0016] An eleventh aspect includes the glass forming apparatus of any preceding aspect, further comprising a glass ribbon sensor for measuring a width of the glass ribbon exiting the slot orifice, the controller operatively connected to the glass ribbon sensor and operable to adjust the flow rate of cooling fluid supplied by the cooling fluid source based on the width of the glass ribbon as measured by the glass ribbon sensor.

[0017] A twelfth aspect includes the glass forming apparatus of any preceding aspect, wherein an insulating sleeve is disposed over at least a portion of the outer tube.

[0018] A thirteenth aspect includes the glass forming apparatus of any preceding aspect, further comprising a glass ribbon sensor for measuring a width of the glass ribbon exiting the slot block.

[0019] A fourteenth aspect includes the glass forming apparatus of any preceding aspect, further comprising a controller operatively connected to the cooling fluid source and the glass ribbon sensor, the controller operable to adjust a flow rate of cooling fluid supplied by the cooling fluid source based on the width of the glass ribbon as measured by the glass ribbon sensor.

[0020] A fifteenth aspect includes the glass forming apparatus of any preceding aspect, wherein at least one of the plurality of channels extends in a plane defined by the vertical dimension and the width dimension, and a length of the at least one of the plurality of channels is parallel with the vertical dimension.

[0021] A sixteenth aspect includes the glass forming apparatus of any preceding aspect, wherein at least one of the plurality of channels extends in a plane defined by the vertical dimension and the width dimension, and a length of the at least one of the plurality of channels is non-parallel with the vertical dimension.

[0022] A seventeenth aspect includes the glass forming apparatus of any preceding aspect, wherein at least one of the plurality of channels extends in a plane defined by the width dimension and the thickness dimension, and a length of the at least one of the plurality of channels is parallel with the thickness dimension.

[0023] An eighteenth aspect includes the glass forming apparatus of any preceding aspect, wherein at least one of the plurality of channels extends in a plane defined by the width dimension and the thickness dimension, and a length of the at least one of the plurality of channels is non-parallel with the thickness dimension. [0024] A nineteenth aspect includes the glass forming apparatus of any preceding aspect, wherein the cooling fluid is an inert gas.

[0025] A twentieth aspect includes the glass forming apparatus of any preceding aspect, wherein the distal end of the outer tube is affixed to the slot block.

[0026] A twenty-first aspect includes a glass forming apparatus comprising: a glass delivery device comprising a slot block through which molten glass flows and is formed into a glass ribbon as it exits an orifice of the slot block, the slot block having a vertical dimension corresponding with a flow direction of the molten glass, a width dimension orthogonal to the vertical dimension, and a thickness dimension orthogonal to the vertical dimension and the width dimension, the slot block comprising an internal cavity positioned proximate to the orifice of the slot block, at least one inlet port in fluid communication with the internal cavity, and at least one outlet port in fluid communication with the internal cavity; and a heat extraction assembly comprising: a cooling fluid input tube connected to the at least one inlet port such that an inner lumen of the cooling fluid input tube is in fluid communication with the internal cavity; a cooling fluid source fluidly coupled to the cooling fluid input tube to thereby supply cooling fluid to the inner lumen of the cooling fluid input tube and the internal cavity; and a cooling fluid output tube connected to the at least one outlet port such that an inner lumen of the cooling fluid output tube is in fluid communication with the internal cavity.

[0027] A twenty-second aspect includes the glass forming apparatus of the twenty-first aspect, wherein the at least one inlet port comprises a single inlet port.

[0028] A twenty-third aspect includes the glass forming apparatus of any of the twenty-first through twenty-second aspects, wherein the at least one outlet port comprises a single outlet port.

[0029] A twenty-fourth aspect includes the glass forming apparatus of any of the twenty- first through twenty-third aspects, wherein the at least one outlet port comprises a plurality of outlet ports, and the cooling fluid output tube comprises a plurality of cooling fluid output tubes that each correspond with one of the plurality of outlet ports.

[0030] A twenty-fifth aspect includes the glass forming apparatus of any of the twenty-first through twenty-fourth aspects, wherein at least one of the plurality of cooling fluid output tubes is closed. [0031] A twenty-sixth aspect includes the glass forming apparatus of any of the twenty-first through twenty-fifth aspects, wherein each of the plurality of cooling fluid output tubes comprises a valve to control a flow of cooling fluid from each of the plurality of cooling fluid output tubes.

[0032] Additional features and advantages of the glass forming apparatus described herein will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art from that description or recognized by practicing the embodiments described herein, including the detailed description which follows, the claims, as well as the appended drawings.

[0033] 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

[0034] The embodiments set forth in the drawings are illustrative and exemplary in nature and not intended to limit the subject matter defined by the claims. The following detailed description of the illustrative embodiments can be understood when read in conjunction with the following drawings, where like structure is indicated with like reference numerals and in which:

[0035] FIG. 1 schematically depicts a glass manufacturing apparatus for forming a glass ribbon;

[0036] FIG. 2A schematically depicts a glass forming apparatus for forming a glass ribbon from molten glass, according to one or more embodiments shown and described herein;

[0037] FIG. 2B schematically depicts a bottom view of the glass forming apparatus of FIG. 2A through the line 2B-2B of FIG. 2A, according to one or more embodiments shown and described herein; [0038] FIG. 2C schematically depicts a vertical cross section of the glass delivery device of FIGS. 2A and 2B through the line 2C-2C of FIG. 2A, according to one or more embodiments shown and described herein;

[0039] FIG. 3A schematically depicts a heat extraction assembly for use with the glass forming apparatus of FIGS. 2A-2C, according to one or more embodiments shown and described herein;

[0040] FIG. 3B is a detailed view of an exhaust channel of the heat extraction assembly of FIG. 3A, according to one or more embodiments shown and described herein;

[0041] FIG. 3C is a detailed view of a portion of the heat extraction assembly of FIG. 3A, according to one or more embodiments shown and described herein;

[0042] FIG. 4A schematically depicts the heat extraction assembly of FIG. 3A engaged with a slot block, according to one or more embodiments shown and described herein;

[0043] FIG. 4B schematically depicts an insulating insert for use with the heat extraction assembly of FIG. 3A and the cooling channel of FIG. 4A, according to one or more embodiments shown and described herein;

[0044] FIG. 4C is a detailed view of the insulating insert positioned within the cooling channel in FIG. 4B, according to one or more embodiments shown and described herein;

[0045] FIG. 5 schematically depicts a slot block of a glass delivery device comprising an internal cavity for use with an alternate heat extraction assembly, according to embodiments shown and described herein;

[0046] FIG. 6 graphically depicts a relationship between the flow rate of cooling fluid (X- axis) and a width of a glass ribbon (Y -axis), according to one or more embodiments shown and described herein;

[0047] FIG. 7 graphically depicts the standard deviation of the left bead position and the right bead position when subjected to different flow rates of cooling fluid;

[0048] FIG. 8 graphically depicts the relationship between sheet width variation and the rate at which cooling fluid is introduced in a channel; and [0049] FIG. 9 graphically depicts thermal modeling calculations of channel locations relative to the comer radius of the slot orifice.

DETAILED DESCRIPTION

[0050] Reference will now be made in detail to embodiments of heat extraction assemblies for glass forming apparatuses, and glass forming apparatuses comprising the same, 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 the heat extraction assembly is schematically depicted in FIG. 3A. The heat extraction assembly may include an outer tube and an inner tube extending within an outer lumen of the outer tube. A distal end of the outer tube is connected to a channel formed in a slot block of the glass forming apparatus, and the inner tube is positioned within the outer tube to deliver cooling fluid to the channel to thereby extract heat from the slot block. Various embodiments of heat extraction assemblies, glass forming apparatuses comprising the same, and methods for using the heat extraction assemblies for manufacturing glass ribbons will be described herein with specific reference to the appended drawings.

[0051] Ranges can be expressed herein as from “about” one particular value, and/or to “about” another particular value. When such a range is expressed, another embodiment includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent “about,” it will be understood that the particular value forms another embodiment. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint.

[0052] Directional terms as used herein - for example up, down, right, left, front, back, top, bottom, upper, lower - are made only with reference to the figures as drawn and are not intended to imply absolute orientation. The terms “proximal” and “distal” are defined herein relative to a slot orifice in a slot block of a glass forming apparatus. The term “distal” refers to the position of an element that is closer to the slot orifice and the term “proximal” refers to the position of an element that is farther away from the slot orifice.

[0053] 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 with any apparatus specific orientations be required. 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.

[0054] 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 aspects having two or more such components, unless the context clearly indicates otherwise.

[0055] Referring to FIG. 1 by way of example, an embodiment of a glass manufacturing apparatus 100 for forming glass ribbons from molten glass is schematically depicted. The glass manufacturing apparatus 100 may include a melter 111, a fining system 113, a mixing vessel 114, a delivery vessel 118, and a glass forming apparatus 120. Glass batch materials are introduced into the melter 111 through a batch inlet port 112. Batch materials are melted in the melter 111 to form molten glass 116. The melter 111 is fluidly coupled to the fining system 113 with a connecting tube 115. The molten glass 116 flows from the melter 111, through the connecting tube 115, and into the fining system 113.

[0056] The fining system 113 may comprise a high temperature processing area that receives the molten glass 116 from the melter 111. While the molten glass 116 is resident in the fining system 113, dissolved gasses and/or bubbles are removed from the molten glass 116. The fining system 113 may be fluidly coupled to the mixing vessel 114 by a connecting tube 140. That is, the molten glass 116 flowing from the fining system 113 to the mixing vessel 114 may flow through the connecting tube 140. As the molten glass 116 passes through the mixing vessel 114, the molten glass 116 may be stirred to homogenize the molten glass 116. The mixing vessel 114 may be, in turn, fluidly coupled to the delivery vessel 118 by a connecting tube 117 such that the molten glass 116 flowing from the mixing vessel 114 to the delivery vessel 118 flows through the connecting tube 117. [0057] The delivery vessel 118 supplies the molten glass 116 through a downcomer 119 into the glass forming apparatus 120. In the embodiments described herein, the glass forming apparatus 120 is a slot draw machine for forming the molten glass 116 into a glass ribbon 123. The glass forming apparatus 120 typically includes a glass delivery device 121 that comprises a slot block 122 through which the molten glass 116 flows and is formed into a glass ribbon 123. The glass delivery device 121 may include an inlet conduit 124 in fluid communication with an inlet orifice of the slot block 122, and the downcomer 119 may be positioned to deliver molten glass 116 from the delivery vessel 118 to the inlet conduit 124 of the glass delivery device 121. In embodiments, the downcomer 119 may be nested within and spaced apart from an inner surface of the inlet conduit 124.

[0058] The slot block 122 of the glass delivery device 121 includes a slot orifice 125 out of which the glass ribbon 123 flows, in a flow direction 126, as a continuous ribbon, and into an annealing region 127. The slot block 122 includes a lip 128 at a lower end of the slot block

122, and the slot orifice 125 is provided in the lip 128. The slot orifice 125 may be an elongated shape that is generally rectangular in cross-section, with semi-circular edges or rounded edges that correspond with edges 123a, 123b of the glass ribbon 123 formed therewith. The glass delivery device 121 defines a passageway 129 within which the molten glass 116 may accumulate and, thereafter, be discharged from the slot orifice 125 in the form of the glass ribbon 123 having a width W that is measured between the edges 123a, 123b of the glass ribbon

123. The glass delivery device 121 and the slot block 122, including the lip 128, may be manufactured from refractory metals, such as platinum or a platinum alloy. Also, while not illustrated in FIG. 1, the glass manufacturing apparatus 100 may include additional components positioned downstream of the glass delivery device 121. For example, annealing devices and a glass separation apparatus for separating the glass ribbon 123 into individual glass sheets may be provided downstream of the glass forming apparatus 120 in the flow direction 126.

[0059] In conventional glass delivery devices 121 comprising a slot block 122, the glass ribbon 123 discharged from the slot block 122 may exhibit stability issues, such as ribbon deflection (side-to-side ribbon walking) and variation in the width W of the glass ribbon 123 (hereinafter, “sheet width variation”). These stability issues may be due to non-uniform thermal characteristics of the glass ribbon 123 as the glass ribbon 123 exits the slot block 122. These non-uniform thermal characteristics may adversely impact the dimensional characteristics of the glass ribbon 123, which, in turn adversely impact the quality of the glass ribbon 123. Heat extraction may be utilized to control the stability of the glass ribbon 123, and thereby minimize ribbon deflection and sheet width variation, such that the glass ribbon 123 dispensed from the slot block 122 exhibits suitable dimensional characteristics (or quality).

[0060] For example, in conventional glass delivery devices 121, such as that schematically depicted in FIG. 1, water-cooled fingers 150, 152 may be utilized to extract heat from the glass ribbon 123 as it passes through the slot block 122 of the glass delivery device 121. The water- cooled fingers 150, 152 may be made from the same material as the slot block 122 and placed in contact with an external surface of the lip 128 (such as abutted against the lip), such that heat is extracted through the material of the lip 128 and into the water-cooled fingers 150, 152, which then exchange the heat with water flowing through the water-cooled fingers 150, 152. However, it has been found that it is difficult to establish good thermal coupling between the water-cooled fingers 150, 152 and the lip 128 to efficiently extract heat from the glass ribbon 123. For example, the water-cooled fingers may not be sufficiently thermally coupled with the external surface of the lip 128, impacting the ability of the water-cooled fingers 150, 152 to extract the desired amount of heat from the slot block 122. Further, the surface of the water- cooled fingers 150, 152 and/or the external surface of the lip 128 may undergo oxidation. The buildup of an oxide layer between the water-cooled fingers 150, 152 and the lip 128 can act as a thermal barrier inhibiting heat extraction by the water-cooled fingers 150, 152. Not only does oxidation inhibit thermal extraction, but oxidation may also eventually necessitate replacement of the slot block 122, which may be expensive and time consuming and may decrease production yields as the glass manufacturing apparatus 100 may be shut down for extended periods of time to facilitate repair and/or replacement.

[0061] Disclosed herein are glass forming apparatuses which include heat extraction assemblies that may mitigate the foregoing problems. In the embodiments described, the slot block of the glass forming apparatus includes channels formed in the slot block adjacent to the slot orifice. Heat extraction assemblies may be thermally coupled to the channels to introduce cooling fluid into the channels. The glass forming apparatuses comprising the heat extraction assemblies described herein may improve sheet width variation and ribbon deflection by providing localized heat extraction within the channels formed proximate the slot orifice.

[0062] Referring now to FIGS. 2A-2C, FIG. 2A schematically depicts a glass forming apparatus 200 for forming a glass ribbon 123 from molten glass 116. In the embodiments described herein, the glass forming apparatus 200 is a slot draw machine that generally includes a glass delivery device 221 comprising a slot block 204 and a heat extraction assembly 400. FIG. 2B is a bottom view of the slot block 204 along the line 2B-2B of FIG. 2A and FIG. 2C is a cross-sectional view of the slot block 204 and a portion of the glass delivery device 221 along the line 2C-2C of the FIG. 2A. The slot block 204 includes a vertical dimension in the direction of the Z-axis of the coordinate axes depicted in the figures, a width dimension in the direction of the X-axis of the coordinate axes depicted in the figures, and a thickness dimension in the direction of the Y-axis of the coordinate axes depicted in the figures. The vertical dimension generally corresponds with the flow direction 126. The width dimension is orthogonal to the vertical dimension, and the width W of the glass ribbon 123 may be evaluated in the width dimension. The thickness dimension is orthogonal to the vertical dimension and the width dimension, and a thickness of the glass ribbon 123 (i.e., the measurement between opposing surfaces of the glass ribbon 123) may be evaluated in the thickness dimension.

[0063] The glass forming apparatus 200 generally includes a glass delivery device 221 that comprises a slot block 204 through which molten glass flows and is formed into a glass ribbon 123. The glass delivery device 221 may include an inlet conduit 203 in fluid communication with an inlet orifice (not depicted) of the slot block 204 such that molten glass flowing through the inlet conduit 203 flows through the glass delivery device 221 and into the slot block 204. Accordingly, the inlet conduit 203 is fluidly coupled to the downcomer 119 (FIG. 1) such that the inlet conduit 203 receives molten glass from the delivery vessel 118, as described herein.

[0064] The slot block 204 of the glass delivery device 221 includes a slot orifice 206 from which the glass ribbon 123 is discharged as a continuous glass ribbon in the flow direction 126. The slot block 204 includes a lip 228 at a lower end of the slot block 204, and the slot orifice 206 is provided in the lip 128. The slot orifice 206 may be an elongated shape that is generally rectangular in cross-section, with semi-circular edges or rounded edges that correspond with edges 123a, 123b of the glass ribbon 123. The glass delivery device 221 defines a passageway 208 within which molten glass 116 from the inlet conduit 203 may accumulate and, thereafter, be discharged from the slot orifice 206 as a glass ribbon 123 having a width W that is measured between edges 123a, 123b of the glass ribbon 123. The glass delivery device 221 and the slot block 204, including the lip 228, may be manufactured from refractory metals, such as platinum or a platinum alloy, or the like.

[0065] In the embodiments of the glass forming apparatus 200 described herein, the slot block 204 of the glass delivery device 221 comprises at least one channel 201 (such as a plurality of channels 201a, 201b, 201c, 20 Id, 20 le, 20 If, 201g, 20 Ih, 20 li, 20 Ij) within which cooling fluid is introduced to facilitate heat extraction from the slot block 204 and the molten glass flowing through the slot block 204. As used herein, reference to “channel 201” refers to any of the channels formed in the slot block 204 (e.g., channels 201a, 201b, 201c, 201d, 201e, 201f, 201g, 201h, 201i, 201j) while reference to “channel 201” with a specific alphabetic designation (i.e., channels 201a, 201b, 201c, 201d, 201e, 20 If, 201g, 201h, 20 li, 20 Ij) refers to the channel having the specific alphabetic designation. The at least one channel 201 is formed in the slot block 204 and includes a length L, and the length L of the at least one channel 201 defines the distance that the corresponding channel extends into the material of the slot block 204. The at least one channel 201 may be fabricated internally within the slot block 204 at desired locations, for example, to reduce the distance between the point of heat extraction and the interface between the slot orifice 206 and the glass ribbon 123 discharged therefrom. With this arrangement, heat transfer occurs between the cooling fluid and a surface inside the at least one channel 201 onto which the cooling fluid is flowed, which provides a better heat transfer interface compared to the water-cooled fingers 150, 152 which exchange heat at a solid-to-solid interface. That is, contact between the cooling fluid and the surface of the at least one channel 201 is more consistent and reproducible, as compared to the solid-to-solid interface of the water-cooled fingers 150, 152 depicted in FIG. 1. Furthermore, forming the at least one channel 201 within the slot block 204 ensures that the point of heat extraction is consistent over time. Further still, the heat extraction assembly 400 described herein allows for adjustment of the flow of cooling fluid to achieve a desired heat extraction. Moreover, the type of cooling fluid utilized may be selected to prevent or mitigate oxidation within the at least one channel 201 and thereby maintain heat transfer (i.e., at an expected amount unaffected by oxidation) at the surface of the at least one channel 201 for the duration of the life span of the slot block 204 and/or the lip 228.

[0066] Referring still to FIG. 2A, the heat extraction assembly 400 is shown coupled to the channel 20 If. While FIG. 2A depicts a heat extraction assembly 400 coupled to the channel 20 If, individual heat extraction assemblies may be coupled to each of the channels formed in the slot block 204. The heat extraction assembly 400 injects cooling fluid into the channel 20 If, and the cooling fluid interacts with the material of the slot block 204 (including the lip 228) at the forming temperature of the glass ribbon 123. Such interaction leads to an exchange of heat from the glass ribbon 123, through the material of the slot block 204, and into the cooling fluid thereby increasing the temperature of the cooling fluid and decreasing the temperature of the slot block 204, the lip 228, and the glass ribbon 123. That is, heat from the glass ribbon 123 exiting the slot orifice 206 is extracted via thermal conduction with the slot block 204 and cooling fluid, which thereby increases the viscosity of the glass ribbon 123, where heat extraction is localized at edges of the slot orifice 206 adjacent to the edges 123a, 123b of the glass ribbon 123. Such increased viscosity provides edge flow stability and mitigates the occurrence of ribbon deflection and sheet width variation.

[0067] In FIG. 2A, the heat extraction assembly 400 is shown extending at an angle relative to the vertical dimension. In this manner, the heat extraction assembly 400 is coupled to the corresponding channel 20 If while avoiding interference with other components of the glass manufacturing apparatus 100 and/or the glass forming apparatus 200, such as the annealing region 127. However, the heat extraction assembly 400 may extend at other angles, such as parallel to or perpendicular to the flow direction 126 and the corresponding channels may extend into the slot block 204 in the same direction. Also, where multiple heat extraction assemblies 400 are utilized, they may each extend at the same angle.

[0068] The heat extraction assembly 400 may be provided in pairs. In embodiments, a second heat extraction assembly, similar to the heat extraction assembly 400, may also be coupled to the channel 20 li, such that a first pair of heat extraction assemblies (each similar to the heat extraction assembly 400) is provided at the channels 20 If, 20 li. In addition to or instead of providing the first pair of heat extraction assemblies at the channels 20 If, 20 li, a second pair of heat extraction assemblies (each similar to the heat extraction assembly 400) may be provided at the channels 20 le, 20 Ih, a third pair of heat extraction assemblies (each similar to the heat extraction assembly 400) may be provided at the channels 201g, 20 Ij, a fourth pair of heat extraction assemblies (each similar to the heat extraction assembly 400) may be provided at the channels 201a, 201c, and/or a fifth pair of heat extraction assemblies (each similar to the heat extraction assembly 400) may be provided at the channels 201b, 201d. Where a single pair of the heat extraction assemblies 400 is utilized, they may each extend at the same angle. For example, the heat extraction assembly 400 coupled to the channel 20 If and the heat extraction assembly 400 coupled to the channel 20 li may extend at the same angle. Where more than one pair of heat extraction assemblies 400 is utilized, all of the heat extraction assemblies 400 may extend at the same angle, or the heat extraction assemblies 400 of at least one pair may extend at a different angle. For example, the heat extraction assemblies 400 coupled to the channels 201a, 201c may extend at a first angle and the heat extraction assemblies 400 coupled to the channels 201b, 20 Id may be differently oriented such that they extend at a second angle that is different than the first angle. Thus, as described further herein, the heat extraction assembly 400 may be coupled to any one or more of the at least one channel 201 and may extend in various orientations.

[0069] Referring now to FIG. 2B, the plurality of channels 201a, 201b, 201c, 201d, 201e, 201f, 201g, 201h, 20 li, 20 Ij are formed into a bottom surface 202 of the slot block 204. The plurality of channels 201a, 201b, 201c, 201d, 201e, 201f, 201g, 201h, 20 li, 20 Ij are positioned at various locations relative to the slot orifice 206. The slot orifice 206 includes a width axis 212’ that is parallel to the width dimension of the slot block 204, and a width of the slot orifice 206 is assessed along the width axis 212’. The slot orifice 206 also includes a thickness axis 214’ that is parallel to the thickness dimension, and a thickness of the slot orifice 206 is assessed along the thickness axis 214’. The width axis 212’ and the thickness axis 214’ bisect the width and the thickness, respectively, of the slot orifice 206. Further, a vertical axis 210’ that extends parallel to the vertical dimension is at the intersection of the width axis 212’ and the thickness axis 214’.

[0070] The location and orientation of the plurality of channels 201a, 201b, 201c, 201d, 20 le, 20 If, 201g, 20 Ih, 20 li, 20 Ij, as well as the number and distribution of the channels, may be selected based on the desired amount of heat extraction and/or the temperature profile desired to be achieved in the slot block 204 for a particular application. Also, the orientation, number, and distribution of the channels 201 may be selected to control the thickness and/or width W of the glass ribbon 123 exiting the slot orifice 206. Thermal modeling and testing may be performed to ascertain how many channels 201 are utilized in a particular application, where the channels 201 are located relative to the slot orifice 206, and the orientation or the channels 201 relative to the slot orifice 206. Thus, the channels 201 may be formed as desired to achieve a desired heat extraction and/or temperature profile within the slot block 204 during operation.

[0071] In the example embodiment depicted in FIG. 2B, the plurality of channels 20 la, 201b, 201c, 20 Id, 20 le, 20 If, 201g, 20 Ih, 20 li, 20 Ij are each located relative to the slot orifice 206, such that localized heat extraction will occur adjacent to or at edges 240, 242 of the slot orifice 206. Here, the edges 240, 242 of the slot orifice 206 are each semi-circular in shape and defined by a comer radius, and with a comer radius axis 244 extending through the comer radius of the edge 240 and a comer radius axis 246 extending through the comer radius of the edge 242. The comer radius axes 244, 246 bisect a circle formed by rotating the radii of the edges 240, 242 360 degrees. The comer radius axes 244, 246 are parallel to thickness axis 214’. Also, each of the plurality of channels 201a, 201b, 201c, 201d, 201e, 20 If, 201g, 201h, 20 li, 201j is positioned along an axis that is parallel to the width axis 212’, on either a first side 230 or a second side 232 of the slot block 204, and offset from the comer radius axes 244, 246 towards the thickness axis 214’ of the slot orifice 206.

[0072] In the illustrated embodiment, each of the plurality of channels 201a, 201b, 201c, 201d, 201e, 201f, 201g, 20 Ih, 20 li, 20 Ij is provided at a midpoint between the slot orifice 206 and a peripheral side wall 216 of the slot block 204. In particular, the channels 20 le, 20 If, 201g, 20 Ih, 20 li, 20 Ij are each formed at a midpoint between a first inner wall 270 of the slot orifice 206 and the first side 230 of the peripheral side wall 216, wherein the glass ribbon 123 contacts the first inner wall 270 during formation. Similarly, the channels 201a, 201b, 201c, 20 Id are each formed at a midpoint between a second inner wall 272 of the slot orifice 206 and the second side 232 of the peripheral side wall 216, wherein the glass ribbon 123 also contacts the second inner wall 272 during formation. However, any one or more of the at least one channel 201 may be nearer or farther from the slot orifice 206 depending on the desired heat extraction at a particular location.

[0073] In the illustrated embodiment, the channel 20 le may be offset by about 5 millimeters (mm) from the comer radius axis 244 associated therewith towards the thickness axis 214’, the channel 201f may be offset by about 17.5 mm from the comer radius axis 244 associated therewith towards the thickness axis 214’, and the channel 201g may be offset by about 30 mm from the comer radius axis 244 associated therewith towards the thickness axis 214’. In this embodiment, the channels 20 Ih, 20 li, 20 Ij are symmetrical with the channels 20 le, 20 If, 201g, respectively about the thickness axis 214’. Thus, the channel 20 Ih may be offset by about 5 mm from the comer radius axis 246 towards the thickness axis 214’; the channel 20 li may be offset by about 17.5 mm from the comer radius axis 246 towards the thickness axis 214’; and the channel 20 Ij may be offset by about 30 mm from the comer radius axis 246 towards the thickness axis 214’. Also, in the illustrated embodiment, the channel 201a may be offset by about 10 mm from the comer radius axis 244 towards the thickness axis 214’, and channel 201b may be offset by about 25 mm from the comer radius axis 244 towards the thickness axis 214’. In this embodiment, the channels 201c, 201d are symmetrical to channels 201a, 201b, respectively, about the thickness axis 214’. Thus, the channel 201c may be offset by about 10 mm from the comer radius axis 246 towards the thickness axis 214’, and the channel 20 Id may be offset by about 25 mm from the comer radius axis 246 towards the thickness axis 214’. However, FIG. 2B illustrates an example of the number and relative positions of the channels 201, and other numbers and relative positions of the channels 201 are contemplated and possible based on the heat extraction and temperature profde desired for a particular application.

[0074] In the illustrated embodiment, each of the plurality of channels 201a, 201b, 201c, 201d, 201e, 201f, 201g, 201h, 201i, 201j may extend in a plane defined by the vertical dimension and the width dimension (i.e., an X-Z plane of the coordinate axes depicted in the figures). As noted herein, the length L of each of the plurality of channels 201a, 201b, 201c, 20 Id, 20 le, 20 If, 201g, 20 Ih, 20 li, 20 Ij corresponds to the distance that the channel extends into the material of the slot block 204 in a direction corresponding to the long axis of the channel. In the depicted embodiment, the length L of each of the plurality of channels 201a, 201b, 201c, 201d, 201e, 201f, 201g, 201h, 201i, 201j is non-parallel with the vertical dimension. In particular, in the illustrated embodiment, each of the plurality of channels 201a, 201b, 201c, 201d, 201e, 201f, 201g, 201h, 201i, 201j is oriented, relative to the bottom surface 202 of the slot block 204, such that each channel extends at a non-zero angle with the vertical dimension in an X-Z plane. In the illustrated embodiment each of the plurality of channels 201a, 201b, 201c, 201d, 201e, 201f, 201g, 201h, 20 li, 20 Ij is oriented at a 45 degree angle with the vertical dimension in the X-Z plane. However, any one or more of the channels 201a, 201b, 201c, 201d, 201e, 20 If, 201g, 201h, 20 li, 201j may extend into the bottom surface 202 of the slot block 204 at a different angle.

[0075] However, any one ormore of the of the plurality of channels 201a, 201b, 201c, 201d, 20 le, 20 If, 201g, 20 Ih, 20 li, 20 Ij may be oriented at angles that are different than the angle of the channels illustrated in FIG. 2B. For example, in embodiments, any one or more of the plurality of channels 201a, 201b, 201c, 201d, 201e, 201f, 201g, 201h, 201i, 201j may be parallel to the vertical dimension (i.e., parallel to the Z-axis of the coordinate axes depicted in the figures). In other embodiments, one ormore of the plurality of channels 201a, 201b, 201c, 201d, 201e, 201f, 201g, 201h, 201i, 201j may extend in a plane defined by the vertical dimension and the thickness dimension (i.e., in the Y-Z plane of the coordinate axes depicted in the figures), wherein the length L of the channel is non-parallel with the vertical dimension of the slot block 204 (i.e., non-parallel with the Z-axis of the coordinate axes depicted in the figures). In other embodiments, one or more of the plurality of channels 201a, 201b, 201c, 201d, 201e, 20 If, 201g, 201h, 20 li, 20 Ij may be oriented in a plane partially defined by the vertical dimension, such that the channel is non-parallel with both the X-Z plane and the Y -Z plane of the coordinate axes depicted in the figures.

[0076] In embodiments, the at least one channel 201 may be provided on a first peripheral side 234 and/or on a second peripheral side 236 of the slot block 204. For example, the at least one channel 201 may be formed into the bottom surface 202 at the first peripheral side 234 and/or the second peripheral side 236, and such channels may extend in planes defined by the vertical dimension (i.e., the Z-axis of the coordinate axes depicted in the drawings) and the thickness dimension (i.e., the Y-axis of the coordinate axes depicted in the drawings) and/or in planes defined by the vertical dimension (i.e., the Z-axis of the coordinate axes depicted in the drawings) and the width dimension (i.e., the X-axis of the coordinate axes depicted in the drawings); and, in such examples, any or all of the channels may be parallel or non-parallel to the vertical dimension (i.e., the Z-axis of the coordinate axes depicted in the drawings). In some examples, the channels may extend into the bottom surface 202 in the X-Z plane along the width axis 212’ and/or may be laterally offset from the width axis 212’ (i.e., toward the first side 230 and/or second side 232). In some examples, the channels may extend into the bottom surface 202 at locations proximate to the first peripheral side 234 and/or the second peripheral side 236 and extend towards the edges 240, 242 of the slot orifice 206 in various orientations that are non-parallel to the width axis 212’.

[0077] In addition to or as an alternative to the embodiments described above, any one or more of the plurality of channels 201a, 201b, 201c, 201d, 201e, 201f, 201g, 201h, 20 li, 20 Ij may be formed into the peripheral side wall 216 of the slot block 204. For example, one or more of the plurality of channels 201a, 201b, 201c, 201d, 201e, 201f, 201g, 201h, 20 li, 20 Ij may extend in the X-Y plane of the coordinate axes depicted in the figures, such that the one or more channel is oriented horizontally. In these embodiments, the length L of the at least one channel 201 maybe oriented parallel with the thickness axis 214’, such that the channel extends through the peripheral side wall 216, toward the slot orifice 206 as indicated by arrows 218a, 218b. It will be appreciated that, while any of the plurality of channels 201a, 201b, 201c, 201d, 20 le, 20 If, 201g, 20 Ih, 20 li, 20 Ij may be oriented as shown by the arrows 218a, 218b, they may be offset from the thickness axis 214’ by various distances, as may be determined by thermal modeling and testing. In embodiments, one or more of the plurality of channels 201a, 201b, 201c, 201d, 201e, 201f, 201g, 201h, 20 li, 20 Ij may extend horizontally in the X-Y plane of the coordinate axes depicted in the figures, wherein the length L of the at least one channel 201 is non-parallel with the thickness axis 214’ . In these embodiments, the channel may extend into the peripheral side wall 216 in a horizontal orientation, for example, as indicated by any one or more of arrows 219a, 219b, 219c, 219d. It will be appreciated that the arrows 219a, 219b are exemplary, and that one or more of the plurality of channels 201a, 201b, 201c, 201d, 201e, 201f, 201g, 201h, 20 li, 20 Ij may be oriented at different angles and/or may be offset from the thickness axis 214’ by various other distances, as may be determined by thermal modeling and testing . As indicated by the arrows 219c, 219d, in embodiments, one or more of the plurality of channels 201a, 201b, 201c, 201d, 201e, 201f, 201g, 20 Ih, 20 li, 20 Ij may extend horizontally in the X-Y plane of the coordinate axes depicted in the figures, wherein the length L of the at least one channel 201 is parallel with the width axis 212’, such that the channel extends in the horizontal direction indicated by the arrows 219c, 219d. However, the arrows 219c, 219d are exemplary, and one or more of the plurality of channels 201a, 201b, 201c, 20 Id, 201e, 201f, 201g, 201h, 20 li, 20 Ij may be offset from (and on either side of) the width axis 212’ by various other distances, as may be determined by thermal modeling and testing. In even other embodiments, any one or more of the plurality of channels 201a, 201b, 201c, 20 Id, 201e, 201f, 201g, 201h, 201i, 20 Ij may be formed into the peripheral side wall 216, but either extend downward toward the bottom surface 202 or extend upward away from the bottom surface 202 (i.e., in a direction out of the X-Y plane of the coordinate axes depicted in the drawings).

[0078] In embodiments, the plurality of channels 201a, 201b, 201c, 201d, 201e, 20 If, 201g, 20 Ih, 20 li, 20 Ij may be organized in sets of channels. In the illustrated embodiment, the plurality of channels 201a, 201b, 201c, 201d, 201e, 20 If, 201g, 201h, 201i, 20 Ij may include a first set of channels 220, a second set of channels 222, a third set of channels 224, and a fourth set of channels 226. Here, the first set of channels 220 includes the channels 20 le, 20 If, 201g that are located progressively farther from the comer radius axis 244; the second set of channels 222 includes the channels 20 Ih, 20 li, 20 Ij that are located progressively farther from the comer radius axis 246; the third set of channels 224 includes channels 201a, 201b that are located progressively farther from the comer radius axis 244; and the fourth set of channels 226 includes the channels 201c, 20 Id that are located progressively farther from the comer radius axis 244. The first set of channels 220 and the second set of channels 220 are positioned at the first side 230 of the slot block 204, and the third set of channels 224 and the fourth set of channels 226 are positioned at the second side 232 of the slot block 204, such that the first set of channels 220 and the second set of channels 220 are positioned opposite the third set of channels 224 and the fourth set of channels 226 with respect to the width axis 212’. Also, the first set of channels 220 and the third set of channels 224 are positioned opposite the second set of channels 222 and the fourth set of channels 226 with respect to the thickness axis 214’. Further, the first set of channels 220 and the third set of channels 224 are symmetrically positioned on opposite sides of the thickness axis 214’, and the second set of channels 222 and the fourth set of channels 226 are also symmetrically positioned on opposite sides of the thickness axis 214’. In embodiments, individual channels within each set of channels may be utilized with the other channels in the set to achieve a desired heat extraction in a portion of the slot block 204. For example, the cooling fluid flow within each channel in the set of channels may be controlled to be the same as other channels in the set to achieve a desired heat extraction profile along a portion of the slot block 204. Alternatively, the cooling fluid flow within individual channels within each set of channels may be independently controlled to achieve a desired heat extraction profile along a portion of the slot block 204. It will be appreciated, however, that FIG. 2B illustrates just a few example groupings of channels and that other groupings of channels may be utilized to achieve a particular heat extraction or temperature profile.

[0079] Referring now to FIG. 2C, FIG. 2C schematically depicts the heat extraction assembly 400 coupled to the channel 20 If. As described further herein, cooling fluid is discharged from the heat extraction assembly 400 and introduced into the channel 20 If for purposes of extracting heat from the material of the slot block 204 and, in turn, from the glass ribbon 123 discharged from the slot block 204. In the embodiment illustrated in FIG. 2C, the channel 20 If includes an open end 320 formed in the bottom surface 202 of the slot block 204, a closed end 322 opposite the open end 320, and a sidewall 330 extending between the open end 320 and the closed end 322. The channel 20 If is formed with sufficient length such that, when evaluated in the vertical dimension, the closed end 322 of the channel 20 If is spaced from the bottom surface 202 of the slot block 204 by a distance 312.

[0080] The closed end 322 of the channel 201f defines a surface that provides the interface for heat transfer between the slot block 204 and the cooling fluid delivered by the heat extraction assembly 400. The sidewall 330 also defines a surface and, in some embodiments, at least a portion of the sidewall 330 is also contacted by the cooling fluid and also serves as the interface for heat transfer. The heat extraction assembly 400 includes an outer tube 402 that is coupled to the channel 102f and an inner tube 410 that extends within the outer tube 402 and discharges cooling fluid into the channel 102f. In some embodiments, a distal end 404 of the outer tube 402 may extend into the channel 20 If such that the outer tube 402 is attached to the sidewall 330 of the channel 201f. In some of these embodiments, the distal end 404 of the outer tube 402 is fully inserted into the channel 201f, such that only the closed end 322 of the channel 201f is exposed to cooling fluid injected by the inner tube 410 (e.g., as the sidewalls 330 are covered by the distal end 404 of the outer tube 402); whereas, in other embodiments, the distal end 404 of the outer tube 402 is only partially inserted into the channel 20 If, such that the closed end 322 and a portion of the sidewall 330 of the channel 20 If are exposed to the cooling fluid, thereby facilitating greater heat extraction from the material of the slot block 204. In even other embodiments, the distal end 404 of the outer tube 402 may be attached to the channel 20 If at the open end 320 thereof on the bottom surface 202 of the slot block 204, such that the entirety of the sidewall 330 and the closed end 322 of the channel 20 If is exposed to cooling fluid, thereby facilitating even greater heat extraction from the material of the slot block 204. Also, the inner tube 410 of the heat extraction assembly 400 is positionable with respect to the outer tube 402 and the closed end 322 of the channel 20 If to further control how the cooling fluid is distributed on the surface area of the channel 20 If, as described in further detail herein. For example, a portion of the inner tube 410 of the heat extraction assembly 400 may be at least partially inserted into the channel 20 If such that the cooling fluid discharged therefrom will be focused at a particular surface within the channel 201f (e.g., the closed end 322 of the channel 20 If). Alternatively, the inner tube 410 may be retracted therefrom to diffuse injection of the cooling fluid, such that the cooling fluid is distributed on a relatively larger surface within the channel 20 If (e.g., on the closed end 322 and at least a portion of the sidewall 330 of the channel 20 If). Thus, heat extraction is generally increased by positioning the inner tube 410 closer to the closed end 322 of the channel 201f. However, back pressure in the channel 20 If increases as the inner tube 410 is positioned closer to the closed end 322 of the channel 201f and, if the inner tube 410 is positioned too close to the closed end 322 of the channel 20 If, it may be difficult to achieve a desired heat extraction. Regardless of how much surface area within the channel 20 If is exposed to the cooling fluid, contact between the cooling fluid and the surface area of the channel 201f is improved (e.g., more consistent and reproducible) as compared to the solid-to-solid interface of the water-cooled fingers described herein. [0081] In the illustrated embodiment, the closed end 322 defines a conical shaped surface. However, it should be understood that the surface defined by the closed end 322 may have other geometries. For example, the closed end 322 may define a flat surface, a semi-circular surface, etc.

[0082] Referring now to FIGS. 3A-3C, FIG. 3A schematically depicts a heat extraction assembly 400, according to one or more embodiments described herein. In the illustrated embodiment, the heat extraction assembly 400 includes an outer tube 402 having a distal end 404 and a proximal end 406. During use, the distal end 404 of the outer tube 402 is affixed to a corresponding channel formed in the slot block 204, for example, as depicted in FIG. 2C. Various means may be utilized to affix the outer tube 402 to the at least one channel 201, including but not limited to welding (including diffusion welding and soldering), utilization of a glass frit material that seals the outer tube 402 to the corresponding channel when heated to an operating temperature of the glass manufacturing apparatus 100, threaded fittings, compression fittings, and the like. In embodiments, the distal end 404 is affixed to the corresponding channel at a breakaway point that allows an operator to detach and remove the heat extraction assembly 400 from the slot block 204.

[0083] The outer tube 402 defines an outer lumen 408 that extends between the distal end 404 and the proximal end 406 of the outer tube 402. The heat extraction assembly 400 also includes an inner tube 410 extending within the outer lumen 408 of the outer tube 402. The inner tube 410 includes a distal end 412 and a proximal end 414. The inner tube 410 is positioned within the outer lumen 408 of the outer tube 402 such that the distal end 412 of the inner tube 410 is positioned proximate to the distal end 404 of the outer tube 402. As shown in FIGS. 3B and 3C, which are detailed views of the inner tube 410 positioned within the outer lumen 408 of the outer tube 402, an outer surface 410’ of the inner tube 410 is spaced apart from an inner surface 402’ of the outer tube 402 to form an exhaust channel 411 between the inner tube 410 and the outer tube 402. Also, as shown in FIG. 3 C, the inner tube 410 includes an inner lumen 413 extending through the inner tube 410 between the proximal end 414 and the distal end 412 of the inner tube 410. In the illustrated embodiment, the distal end 412 of the inner tube 410 is open to facilitate emitting cooling fluid from the inner lumen 413 of the inner tube 410. In embodiments, the opening in the distal end 412 of the inner tube 410 may have geometries that facilitate directing the cooling fluid emitted therefrom. In embodiments, a chamfer may be formed between the opening at the distal end 412 and a sidewall of the inner tube 410 (e.g., by slicing off a distal comer of the inner tube 410), wherein an inner lumen 413 of the inner tube 410 is exposed through the chamfer such that cooling fluid may be directed out of the chamfer in the inner tube 410. In embodiments, the chamfer may be formed in the inner tube 410 such that it is directed towards or facing the bottom surface 202 of the slot block 204.

[0084] Referring again to FIG. 3A, in the illustrated embodiment a cooling fluid source 420 is fluidly coupled to the inner tube 410 to thereby supply a cooling fluid to the inner lumen 413 (FIG. 3C) of the inner tube 410. The cooling fluid may be circulated from the cooling fluid source 420, through the inner lumen 413 of the inner tube 410, into a channel 201 of the slot block 204 (FIGS. 2A-2C), and exhausted from the channel 201 of the slot block 204 through the exhaust channel 411 formed between the inner tube 410 and the outer tube 402 in the outer lumen 408 of the outer tube 402. As depicted in FIG. 3 A, a fitting 422 may be provided on the proximal end 414 of the inner tube 410 and the cooling fluid source 420 may be coupled to the fitting 422 via a conduit 424, such as a hose. In embodiments, the cooling fluid supplied by the cooling fluid source 420 is a gas or a liquid. In embodiments, the cooling fluid may be an inert gas that will help inhibit oxidation inside the at least one channel 201. In embodiments, the inert gas is nitrogen or argon. In embodiments, the cooling fluid may be liquid water or another liquid coolant. Also, a pressure sensor 425 may be provided for measuring pressure of the cooling fluid supplied to the inner lumen 413 of the inner tube 410. In embodiments, the pressure sensor 425 is a pressure transducer.

[0085] In embodiments, the flow rate at which the cooling fluid source 420 supplies the cooling fluid is controllable. For example, the cooling fluid source 420 may include a variable speed pump and/or valves operable to control the flow rate at which the cooling fluid is supplied to the inner tube 410. In embodiments, the flow rate at which the cooling fluid is supplied may be between 0 standard liters per minute (“slpm”) and 100 slpm. In embodiments, the flow rate of the cooling fluid is up to 80 slpm or even up to 60 slpm. In embodiments, the flow rate at which the cooling fluid is supplied is selected to achieve a desired temperature profile in the slot block 204.

[0086] In embodiments, heat extraction assembly 400 may comprise a cooling fluid temperature sensor 426 operable to measure a temperature at which the cooling fluid is supplied to the inner tube 410 (i.e., an input temperature of the cooling fluid). In embodiments, the cooling fluid temperature sensor 426 may be positioned at the cooling fluid source 420; however, it should be understood that the cooling fluid temperature sensor 426 may be located elsewhere. For example, in embodiments, the cooling fluid temperature sensor 426 may be integrated within a portion of the conduit 424 or positioned proximate to the proximal end 414 of the inner tube 410. In embodiments, the cooling fluid temperature sensor 426 is a thermocouple.

[0087] In embodiments, the inner tube 410 and the outer tube 402 may be designed to control the pressure and/or the velocity of the cooling fluid when introduced into a channel 201 in the slot block 204. For example, an inner diameter of the inner tube 410 and an inner diameter of the outer tube 402 may be selected to have a particular ratio, wherein the ratio of the inner diameters controls the pressure and/or the velocity of the cooling fluid introduced into the corresponding channel. For example, in embodiments, the cooling fluid may have a pressure of up to about 586 kilopascal (“kPa”). Because the flow rate of the cooling fluid into the channel 201 depends on the inner diameter of the inner tube 410, increasing the cross-sectional area of the inner lumen 413 of the inner tube 410 will allow larger flow rates of cooling fluid to be supplied therethrough; however, the diameter of the outer tube 402 may be selected such that the cross-sectional area of the exhaust channel 411 is sufficiently large to exhaust the cooling fluid and minimize (or maintain) back pressure formed within the channel 201 to levels that do not adversely impact heat extraction. In embodiments, the cross-sectional surface area of the exhaust channel 411 is larger than the cross-sectional area of the inner lumen 413 of the inner tube 410.

[0088] In embodiments, the heat extraction assembly 400 may also include a housing 430 that defines an internal channel 432. In the illustrated embodiment, the outer tube 402 is connected to the housing 430 such that the outer lumen 408 of the outer tube 402 is in fluid communication with the internal channel 432 of the housing 430. In this embodiment, the proximal end 406 of the outer tube 402 may extend into a corresponding bore 431 formed in a distal end 433 of the housing 430, such that the outer lumen 408 of the outer tube 402 is in fluid communication with the internal channel 432. In this embodiment, the inner tube 410 passes through the internal channel 432 of the housing 430.

[0089] The heat extraction assembly 400 may further include an exhaust manifold 434 including an exhaust lumen 436. The exhaust manifold 434 is fluidly coupled to the internal channel 432 of the housing 430 such that the exhaust lumen 436 of the exhaust manifold 434 is in fluid communication with the internal channel 432 of the housing 430. During operation, the cooling fluid source 420 supplies the cooling fluid to the inner lumen 413 of the inner tube 410, and the inner tube 410 then directs the cooling fluid into contact with a surface of a corresponding channel formed in the slot block 204, as described herein. The cooling fluid is then exhausted out of the heat extraction assembly 400 via the outer tube 402, specifically through the exhaust channel 411 formed between the inner tube 410 and the outer tube 402, into the internal channel 432 of the housing 430, and out of the internal channel 432 of the housing through the exhaust lumen 436 of the exhaust manifold 434. That is, the exhaust manifold 434 is fluidly coupled to the outer lumen 408 of the outer tube 402 for exhausting cooling fluid from the outer lumen 408 and, in particular, through the exhaust channel 411 formed between the inner surface 402’ of the outer tube 402 and the outer surface 410’ of the inner tube 410.

[0090] Heat extraction assembly 400 may comprise an exhaust temperature sensor 460 for measuring a temperature of cooling fluid exhausted by the heat extraction assembly 400 (i.e., an output temperature of the cooling fluid). In embodiments, the exhaust temperature sensor 460 may be operably coupled to the exhaust manifold 434, for example, to measure a temperature of the cooling fluid as it is exhausted through the exhaust lumen 436. In embodiments, an exhaust apparatus 462 is provided that is in fluid communication with the exhaust lumen 436 such that the exhaust apparatus 462 receives the exhausted cooling fluid. The exhaust apparatus 462 may be coupled to the exhaust manifold 434 via a conduit 464, such as a hose. In embodiments, the exhaust temperature sensor 460 is positioned in the exhaust lumen 436 of the exhaust manifold 434 such that it measures the temperature of the cooling fluid within the exhaust lumen 436. In other embodiments, the exhaust temperature sensor 460 may be positioned in the exhaust apparatus 462, or the exhaust temperature sensor 460 may be positioned on the conduit 464 to measure the temperature of the cooling fluid within a lumen thereof. In other embodiments, the exhaust temperature sensor 460 may be positioned on the housing 430 to measure the temperature of the cooling fluid within the internal channel 432 of the housing 430. In embodiments, the exhaust temperature sensor 460 is a thermocouple.

[0091] In embodiments, at least a portion of the outer surface of the outer tube 402 is insulated, to thereby minimize or negate effects of ambient temperatures outside of the outer tube 402 on the cooling fluid as it is exhausted. In an embodiment, a portion of the outer tube 402 may be covered with an insulating sleeve. Similarly, depending on the location at which the exhaust temperature sensor 460 is provided, at least a portion of the housing 430, the exhaust manifold 434, and or the conduit 464 may be insulated to minimize or negate the effects of ambient temperature.

[0092] In the illustrated embodiment of the heat extraction assembly 400, a connector 440 may be slidably positioned within the housing 430. The connector 440 may include an inner passageway through which the inner tube 410 extends. In particular, the connector 440 may be slidably positioned in a connector channel 442 of the housing 430. As described herein, the inner tube 410 extends through the internal channel 432 of the housing 430 and into the inner passageway of the connector 440. In these embodiments, the inner tube 410 is fixedly coupled to the connector 440, whereby translating the connector 440 along an axis 444 relative to the housing 430 slidably adjusts a spacing 446 between the distal end 412 of the inner tube 410 and the distal end 404 of the outer tube 402. This arrangement enables coarse adjustment of the distal end 412 of the inner tube 410 relative to the distal end 404 of the outer tube 402 as well as coarse adjustment of the distal end 412 of the inner tube 410 within a corresponding channel of the slot block 204. For example, in embodiments, the connector 440 may be translated into the housing 430 to adjust the relative spacing 446 between the distal end 412 of the inner tube 410 and the distal end 404 of the outer tube 402. In these embodiments, the connector 440 may be translated into the housing 430 such that the distal end 412 of the inner tube 410 projects from the distal end 404 of the outer tube 402. Conversely, the connector 440 may also be translated out of the housing 430 to adjust the spacing 446 between the distal end 412 of the inner tube 410 and the distal end 404 of the outer tube 402.

[0093] In embodiments, the inner tube 410 may extend through the inner passageway of the connector 440, such that the proximal end 414 of the inner tube 410 is located proximal from the connector 440 and the distal end 412 of the inner tube 410 is located distal from the connector 440. In other embodiments, the inner tube 410 may be formed of more than one discrete tube, for example, the distal end 412 may be provided on a first tube and the proximal end 414 may be provided on a second tube that is separate from the first tube, where a proximal end of the first tube and a distal end of the second tube are each sealed within the inner passageway of the connector 440, such that the inner passageway fluidly couples the first tube and the second tube.

[0094] In embodiments, the connector channel 442 may limit distal movement of the connector 440. For example, the connector channel 442 may have a larger diameter (or size) than the internal channel 432, such that an interface 448 is defined between the connector channel 442 and the internal channel 432. In this embodiment, the connector 440 has a diameter that generally corresponds in size with the connector channel 442 to allow for translation of the connector 440 in the connector channel 442. As the connector 440 slides into the housing 430 in the connector channel 442, the connector 440 eventually contacts the interface 448 that inhibits further movement of the connector 440 into the housing 430. In embodiments, the connector channel 442 is sized such that, when a distal end 443 of the connector 440 contacts the interface 448, the distal end 412 of the inner tube 410 extends out of the outer lumen 408 of the outer tube 402 such that the distal end 412 of the inner tube 410 is proud of the distal end 404 of the outer tube 402. In this manner, the distal end 412 of the inner tube 410 may extend into the channel 201. In embodiments, when the distal end 443 of the connector 440 contacts the interface 448, the distal end 412 of the inner tube 410 contacts the closed end 322 of the channel 20 If.

[0095] Still referring to FIG. 3 A, housing 430 may include a set screw 450 for locking the connector 440 in position in the housing 430. In the illustrated embodiment, the set screw 450 is threadably inserted into the housing 430 and is operable to lock the connector 440 to the housing 430 and thereby inhibit further translation of the connector 440 upon rotation of the set screw 450 in a first rotational direction. Here, rotation of the set screw 450 in an opposite, second rotation direction would loosen the set screw 450 and thereby allow translational movement of the connector 440 within the housing 430.

[0096] In the illustrated embodiment, the inner tube 410 is threadably coupled to the connector 440, whereby rotation of the inner tube 410 within and relative to the connector 440 adjusts the spacing 446 between the distal end 412 of the inner tube 410 and the distal end 404 of the outer tube 402. In particular, an outer surface 454 of the inner tube 410 may comprise threads 452 engaged with corresponding threads within the inner passageway of the connector 440. The threads 452 and the corresponding threads of the connector 440 may be of known pitch such that it is possible to determine the distance that the inner tube 410 translates along the axis 444 based upon the degree that the inner tube 410 is rotated relative to the connector 440. The threaded interface between the inner tube 410 and the connector 440 enables fine adjustment of the distal end 412 of the inner tube 410 relative to the distal end 404 of the outer tube 402.

[0097] Based on the foregoing, the heat extraction assembly 400 may include a coarse adjustment feature and a fine adjustment feature, both of which may be utilized to adjust the relative spacing 446 between the distal end 412 of the inner tube 410 and the distal end 404 of the outer tube 402. Adjusting the relative spacing 446 between the distal end 412 of the inner tube 410 and the distal end 404 of the outer tube 402 may be utilized to adjust how much of the inner surface of the corresponding channel in the slot block 204 is contacted by cooling fluid emitted from the inner tube 410 and, as result, may be used to control the amount of heat extracted from the material of the slot block 204 and the amount of heat extracted from the glass ribbon discharged from the slot block 204. With the course adjustment feature, the set screw 450 may be loosened and, thereafter, the connector 440 may be translated along the axis 444 to thereby move the inner tube 410 toward the closed end 322 of the at least one channel 201. When the distal end 412 of the inner tube 410 contacts the closed end 322 of the at least one channel 201 (or some other feature in the at least one channel 201 that inhibits further translation), the set screw 450 may be tightened to thereby lock the connector 440 in position, which subsequently serves as a reference point. Then, the fine adjustment feature may be utilized to precisely position the distal end 412 of the inner tube 410 relative to the closed end 322 of the corresponding channel 201. For example, the inner tube 410 may be rotated a certain number of times relative to the connector 440 to translate the distal end 412 of the inner tube 410 and thereby create the spacing 446 desired for the particular amount of heat extraction. In embodiments, the inner tube 410 may be rotated within the connector 440 by an amount that will translate the distal end 412 into a position where the distal end 412 of the inner tube 410 is located 0 mm to 10 mm from the distal end 404 of the outer tube 402, wherein the distal end 404 of the outer tube 402 is located a predetermined distance from the closed end 322 of the at least one channel 201. Thus, the coarse adjustment feature allows the user to set a reference point during installation, and the fine adjustment feature allows the user to position the distal end 412 of the inner tube 410 in a target position relative to the closed end 322 of the at least one channel 201. The coarse adjustment feature and the fine adjustment feature, together with the fixed dimensions of the corresponding channel 201 formed in the slot block 204, allows a user to accurately position the heat extraction assembly 400 to achieve a particular amount of heat extraction and, moreover, to reproduce that heat extraction during subsequent uses. For example, the coarse adjustment feature may be utilized to insert the inner tube 410 farther into the channel 201 to be closer to the closed end 322 thereof and thereby increase heat extraction, and then the fine adjustment feature may be utilized to reposition the inner tube 410 as appropriate to achieve an acceptable amount of back pressure while maximizing heat extraction. [0098] In the embodiments described herein, heat extraction may be achieved by injecting the cooling fluid into a channel 201 to which the heat extraction assembly 400 is coupled. In embodiments, the amount of heat extraction may be quantified using data captured by the cooling fluid temperature sensor 426 and the exhaust temperature sensor 460, where the cooling fluid temperature sensor 426 measures a temperature of the cooling fluid supplied to the inner tube 410 and the exhaust temperature sensor 460 measures a temperature of the cooling fluid in the exhaust manifold 434. In the illustrated embodiment, a controller 470 may be operatively connected to the cooling fluid temperature sensor 426 and the exhaust temperature sensor 460. The controller 470 may be programmed to calculate the amount of heat extracted from the slot block 204 based on the temperature of the cooling fluid in the exhaust manifold 434 and the temperature of the cooling fluid supplied by the cooling fluid source 420. In embodiments, the controller 470 may be communicatively coupled to the cooling fluid source 420 and operable to adjust the flow rate of cooling fluid supplied by the cooling fluid source 420 based on the calculated heat extraction. For example, the controller 470 may be in communication with the cooling fluid source 420 and operable to control operation thereof and, if the controller 470 determines that the calculated heat extraction in the at least one channel 201 departs from a target heat extraction for the corresponding channel 201, the controller 470 causes the cooling fluid source 420 to adjust the flow rate of the cooling fluid to thereby increase or decrease the heat extraction from the corresponding channel 201 until the calculated heat extraction reaches the target heat extraction. In embodiments, the controller 470 includes a mass flow controller for controlling a flow rate of the cooling fluid source 420. In other embodiments, a controller of the cooling fluid source 420 may be a mass flow controller.

[0099] In embodiments, the controller 470 is communicatively coupled to the pressure sensor 425 and is operable to calculate back pressure within the channel 201. Back pressure of the cooling fluid in the channel 201 may be calculated based on various operating parameters that are monitored in real time, such as the flow rate of the cooling fluid measured by cooling fluid source 420, the input pressure of the cooling fluid supplied to the inner tube 410 as measured by the pressure sensor 425, the temperature of the cooling fluid input into the channel 201 as measured by the cooling fluid temperature sensor 426, and the temperature of the cooling fluid exhausted from the channel 201 as measured by the exhaust temperature sensor 460. Based on the calculated back pressure, the operator may then adjust the position of the inner tube 410 within the outer tube 402 and, in some embodiments, the controller 470 is operable to adjust the flow rate of cooling fluid supplied by the cooling fluid source 420 based on the calculated back pressure.

[00100] In embodiments, glass forming apparatus 200 may comprise a glass ribbon sensor 472 for measuring the width W of the glass ribbon 123. Where utilized, the glass ribbon sensor 472 may be positioned to measure the width W of the glass ribbon 123 after the glass ribbon 123 is discharged from the slot block 204. For example, with reference to FIGS. 2A and 3A, the glass ribbon sensor 472 may be positioned proximate to the annealing region 127 and downstream of slot block 204 such that it is able to accurately measure the width W of the glass ribbon 123 as it is discharged from the slot orifice 206. In other embodiments, the glass ribbon sensor 472 may be located downstream of the slot orifice 206 and upstream of the annealing region 127. In embodiments, the glass ribbon sensor 472 may be a thermal camera.

[00101] In embodiments, the controller 470 may be operatively coupled to the glass ribbon sensor 472 and operable to adjust the flow rate of the cooling fluid supplied by the cooling fluid source 420 based on the width W of the glass ribbon 123 as measured by the glass ribbon sensor 472. As previously mentioned, the amount of heat exchange occurring within the plurality of channels 201 depends on the flow rate of the cooling fluid supplied by the cooling fluid source 420, and the controller 470 controls the cooling fluid source 420 to achieve the target heat extraction based on feedback from the cooling fluid temperature sensor 426 and the exhaust temperature sensor 460.

[00102] If the controller 470 determines that the glass ribbon 123 exhibits sheet width variations based on feedback signals from the glass ribbon sensor 472, the controller 470 may be operable to adjust heat extraction occurring in the plurality of channels 201 formed in the slot block 204 to control the width W of the glass ribbon 123 in real time. For example, increased heat extraction from the slot block 204 (and hence the glass ribbon 123 discharged therefrom) corresponds with an increase in the viscosity of the glass ribbon 123, and increased viscosity at the edges 123a, 123b of the glass ribbon 123 reduces the amount of attenuation (narrowing) in the width W of the glass ribbon 123. However, too much heat extraction at the edges 123a, 123b of the glass ribbon 123 may result in a narrowing of the width W of the glass ribbon 123. For example, too much heat extraction at the edges 240, 242 of the slot orifice 206 may cause the edges 123a, 123b of the glass ribbon 123 to have an increased viscosity such that the molten glass 116 within the slot orifice 206 is effectively frozen at locations proximate to the edges 240, 242, which thereby increases flow through the center of the slot orifice 206 as that route is the path of least resistance, and thereby results in narrowing of the glass ribbon 123. Thus, the amount of heat extracted from the glass ribbon 123 may be controlled to ensure that the width W of the glass ribbon 123 is maintained within a desired tolerance. In embodiments, the controller 470 may be operable to stabilize the glass ribbon 123 by controlling the cooling fluid source 420 based on feedback from the cooling fluid temperature sensor 426, the exhaust temperature sensor 460, and the glass ribbon sensor 472.

[00103] Referring now to FIG. 4A, FIG. 4A schematically depicts a bottom view of an embodiment of the slot block 204 having a channel formed therein, according to one or more embodiments. In particular, FIG. 4A is a partial view of the slot block 204 and the slot orifice 206. In the illustrated embodiment, a channel 488 is formed in the material of the slot block 204. The channel 488 is shown extending toward the slot orifice 206. During use, the heat extraction assembly 400 injects the cooling fluid into the channel 488 to thereby extract heat from the slot block 204.

[00104] In the illustrated embodiment, the channel 488 includes a proximal portion 540 closest to the heat extraction assembly 400 (e.g., farthest from the slot orifice 206) and a distal portion 542 farthest from the heat extraction assembly 400 (e.g., closest to the slot orifice 206), wherein the distal portion 542 includes a closed end 550. In this embodiment, the distal portion 542 of the channel 488 may have a smaller diameter than the proximal portion 540, such that the channel 488 also includes a proximally facing annular wall 544 defined between the proximal portion 540 and the distal portion 542 of the channel 488.

[00105] The heat extraction assembly 400 may be connected to the channel 488 to facilitate injection of the cooling fluid into the channel 488. In particular, the outer tube 402 of the heat extraction assembly may be positioned within the proximal portion 540 of the channel 488 and affixed therein, with the distal end 404 of the outer tube 402 abutting the proximally facing annular wall 544 defined between the proximal portion 540 and the distal portion 542 of the channel 488. The distal end 404 of the outer tube 402 may be affixed in a variety of manners, for example, via welding, fittings, threads, or the use of a glass frit material that (when heated) forms a seal between the channel 488 and the outer tube 402.

[00106] In embodiments, the proximal portion 540 of the channel 488 may be of a known length (e.g., the distance between the proximally facing annular wall 544 and the closed end 550 is known) such that, when the distal end 404 of the outer tube 402 abuts the proximally facing annular wall 544, the distal end 404 of the outer tube 402 will similarly be positioned at a known distance from the closed end 550 of the channel 488. After affixing the outer tube 402 to the slot block 204, the coarse adjustment feature and the fine adjustment feature may be utilized to translate the inner tube 410 and thereby adjust aposition of the distal end 412 of the inner tube 410. In the embodiment depicted, the inner tube 410 has been adjusted such that the distal end 412 of the inner tube 410 is spaced apart from the closed end 550 of the at least one channel 488. Once the distal end 412 of the inner tube 410 has been appropriately positioned, cooling fluid may be injected into the at least one channel 488 from the inner lumen 413 of the inner tube 410, such that heat extraction may occur via forced convection. Embodiments of the channel 488 with the proximally facing annular wall 544 (defined between the proximal portion 540 of the channel and the distal portion 542 of the channel 488) may be used in conjunction with any of the embodiments of a glass delivery device described herein.

[00107] Referring now to FIGS. 4B and 4C, FIG. 4B illustrates an embodiment where an insulating insert 560 may be utilized to control heat extraction from within the channel 488 of the slot block 204. FIG. 4C illustrates a detailed view of the insulating insert 560 positioned within the channel 488 of FIG. 4B. As shown, the insulating insert 560 may be partially disposed in the channel 488 and partially disposed in the outer tube 402 of the heat extraction assembly 400. In the illustrated embodiment, the insulating insert 560 may include a proximal portion 562 closest to the heat extraction assembly 400 and a distal portion 564 farthest from the heat extraction assembly 400. The distal portion 564 of the insulating insert 560 may be positioned within the distal portion 542 of the channel 488, and the proximal portion 562 of the insulating insert 560 may be positioned within the proximal portion 540 of the channel 488.

[00108] In this embodiment, the insulating insert 560 may be generally cylindrical in shape, such that the proximal portion 562 and the distal portion 564 have the same outer diameter. The outer diameter of the insulating insert 560 corresponds with an inner diameter of the distal portion 542 of the channel 488, such that an outer surface of the distal portion 564 of the insulating insert 560 is in contact with an interior surface of the distal portion 542 of the channel 488. However, because the proximal portion 540 of the channel 488 is larger in diameter than the distal portion 542 of the channel 488, an annular space is defined between an outer surface of the proximal portion 562 of the insulating insert 560 and an inner surface of the proximal portion 540 of the channel 488. [00109] When the heat extraction assembly 400 is affixed to the slot block 204, the distal end 404 of the outer tube 402 is positioned within the proximal portion 540 of the channel 488, with an outer surface of the distal end 404 of the outer tube 402 contacting the inner surface of the proximal portion 540 of the channel 488. In particular, the distal end 404 of the outer tube 402 will be positioned in the annular space that is defined between the outer surface of the proximal portion 562 of the insulating insert 560 and the inner surface of the proximal portion 540 of the channel 488. The distal end 404 of the outer tube 402 may be permanently or removably connected within the proximal portion 540 of the channel 488, for example, via welding, frit material, threads, etc.

[00110] In this embodiment, the proximal portion 562 of the insulating insert 560 extends into the outer tube 402 of the heat extraction assembly 400, such that the proximal portion 562 of the insulating insert 560 may be positioned within the exhaust channel 411 defined between the inner surface 402’ of the outer tube 402 and the outer surface 410’ of the inner tube 410. Here, the outer surface of the proximal portion 562 of the insulating insert 560 contacts the inner surface 402’ of the outer tube 402. Further, an inner surface of the insulating insert 560 may be spaced apart from the outer surface 410’ of the inner tube 410, such that the insulating insert 560 does not fully occupy the exhaust channel 411 and clearance is provided for exhausting the cooling fluid as described herein.

[00111] In embodiments, the proximal portion 562 (of the insulating insert 560) is press-fit within the outer lumen 408 of the outer tube 402. In some embodiments, an adhesive is utilized to affix the insulating insert 560 within the outer tube 402. In some embodiments, the outer surface of the proximal portion 562 of the insulating insert 560 may comprise threads that correspond to threads formed in the outer lumen 408 of the outer tube 402 such that the insulating insert 560 threadably engages the heat extraction assembly 400.

[00112] The insulating insert 560 may be configured to control the direction of heat extraction from the channel 488. In embodiments, the insulating insert 560 may be at least partially open. For example, one or more openings 561 may be formed in the insulating insert 560 and, when the insulating insert 560 is installed in the channel 488, the material of the slot block 204 within the channel 488 is exposed through the one or more openings 561 and the cooling fluid is able to contact that exposed material of the slot block 204. Greater heat extraction may occur at areas of the channel 488 that are exposed to the cooling fluid, as compared to areas of the channel 488 that are covered by the insulating insert 560. Thus, one or more openings 561 may be formed in the insulating insert 560 to direct or enhance heat extraction at certain areas of the slot block 204, while minimizing heat extraction in other areas of the slot block 204, such as areas where cooling can induce devitrification. For example, the one or more openings 561 may be oriented towards the slot orifice 206 and/or the bottom surface 202 of the slot block 204. Also, by orienting the one or more openings 561 towards the bottom surface 202 of the slot block 204, it is possible to reduce the heat of the glass ribbon 123 exiting the slot orifice 206 and to also cool a region below the slot block 204 where a muffle assembly (not shown) may be provided.

[00113] In the illustrated embodiment, the one or more openings 561 of the insulating insert 560 include an open end 566 and an opening 568. Here, the open end 566 and the opening 568 are formed in the distal portion 564 of the insulating insert 560. In other embodiments, the opening 568 may at least partially extend through the proximal portion 562 of the insulating insert 560. Here, the open end 566 faces the slot orifice 206 and the opening 568 faces the bottom surface 202 of the slot block 204. Also, the opening 568 may be in the form of a proximally extending gap in the insulating insert 560. Thus, the insulating insert 560 illustrated in FIGS. 4B and 4C may be configured to provide increased heat extraction and cooling toward a portion of the slot orifice 206 proximate the bottom surface 202 of the slot block 204 and toward the bottom surface 202 of the slot block 204, while also comparatively reducing heat extraction and cooling toward the top of the slot block 204 (i.e., opposite the bottom surface 202).

[00114] However, the insulating insert 560 may be provided in a partially open manner different than as illustrated in FIGS. 4B and 4C. For example, the insulating insert 560 may include a closed end or a partially closed end, the opening 568 may be larger or smaller, the proximal portion 562 and/or the distal portion 564 may comprise one or more other openings, proximal portion 562 and/or the distal portion 564 may comprise one or more gaps (e.g., in addition to the opening 568), etc. In still other embodiments, the insulating insert 560 may not include any such opening and fully insulates the entirety of the surface within the channel 488.

[00115] In embodiments, the insulating insert 560 may be made from thermally insulating material that, when placed between the cooling fluid and the material of the slot block 204, would decrease heat exchange there between. In particular, the insulating insert 560 may be made from a material that has a lower thermal conductivity relative to the material of the slot block 204. In embodiments, the insulating insert 560 is made from a ceramic material, pure silica, quartz, or alumina. Embodiments of the insulating insert 560 depicted in FIGS. 4B and 4C may be used in conjunction with any of the embodiments of a glass delivery device described herein.

[00116] FIG. 5 schematically depicts a bottom view of an embodiment of the slot block 204 having an internal cavity 572 formed therein, according to one or more embodiments. In particular, FIG. 5 illustrates a partial view of the slot block 204 and the slot orifice 206. In the illustrated embodiment, the internal cavity 572 is formed in the material of the slot block 204 and extends along the slot orifice 206 in the width dimension (e.g., along the X-axis of the coordinate axes depicted in the drawings). During use, a heat extraction assembly 570 may inject cooling fluid into the internal cavity 572 to thereby extract heat from the slot block 204 as described below.

[00117] In the illustrated example, a plurality of ports 574 may be formed in the slot block 204. As shown, the plurality of ports 574 may extend from the internal cavity 572 to an exterior of the slot block 204, such as the peripheral side wall 216 of the slot block 204. As further described, at least one of the plurality of ports 574 may be an inlet port in fluid communication with the internal cavity 572 and at least one of the plurality of ports 574 may be an outlet port in fluid communication with the internal cavity 572. While the plurality of ports 574 in the illustrated embodiment includes a first port 574a, a second port 574b, a third port 574c, and a fourth port 574d, more or less than four of the plurality of ports 574 may be utilized in other embodiments.

[00118] The heat extraction assembly 570 may include a plurality of tubes 578 each extending through a respective one of the plurality of ports 574. In the illustrated embodiment, the plurality of tubes 578 may include a first tube 584a, a second tube 584b, a third tube 584c, and a fourth tube 584d. However, in embodiments utilizing more or less of the plurality of ports 574, more or less of the plurality of tubes 578 may similarly be utilized, such that the plurality of tubes 578 correspond in number to the number of the plurality of ports 574.

[00119] Here, the first tube 584a extends through the first port 574a, the second tube 584b extends through the second port 574b, the third tube 584c extends through the third port 574c, and the fourth tube 584d extends through the fourth port 574d. Also, a lumen of the first tube 584a may be in fluid communication with the internal cavity 572, a lumen of the second tube 584b may be in fluid communication with the internal cavity 572, a lumen of the third tube 584c may be in fluid communication with the internal cavity 572, and a lumen of the fourth tube 584d may be in fluid communication with the internal cavity 572.

[00120] At least one tube of the plurality of tubes 578 may be a cooling fluid input tube operable to inject cooling fluid into the internal cavity 572 of the slot block 204, and at least one tube of the plurality of tubes 578 may be a cooling fluid output tube operable to exhaust cooling fluid from the internal cavity 572 of the slot block 204. Further, a cooling fluid source 580 may be fluidly coupled to the cooling fluid input tube to thereby supply cooling fluid to the inner lumen of the cooling fluid input tube and to the internal cavity 572. The cooling fluid source 580 may include a mass flow controller. An exhaust apparatus 582 may be fluidly coupled to the cooling fluid output tube to exhaust cooling fluid out of the internal cavity 572, through the lumen of cooling fluid output tube. The heat profde formed in the slot block 204 during operation, as well as the amount of heat extracted from the slot block 204 and the amount of time that the cooling fluid remains in the internal cavity 572 (i.e., the dwell time), may be controlled by selecting which of the plurality of tubes 578 function as cooling fluid input tubes, which function as cooling fluid output tubes, and which are closed or blocked off such that they function as neither.

[00121] In the illustrated embodiment, the first tube 584a may be fluidly coupled to the cooling fluid source 580, whereas the second tube 584b, the third tube 584c, and the fourth tube 584d may each be fluidly coupled to the exhaust apparatus 582. Thus, in this embodiment, the first tube 584a supplies the cooling fluid to the internal cavity 572, whereas the second tube 584b, the third tube 584c, and the fourth tube 584d exhaust the cooling fluid therefrom. In other embodiments, one or more of the second tube 584b, the third tube 584c, and the fourth tube 584d may be fluidly coupled to the cooling fluid source 580 instead of exhaust apparatus 582, such that more than one of the plurality of tubes 578 may function as a cooling fluid input tube. In even other embodiments, the first tube 584a may be fluidly coupled to the exhaust apparatus 582, instead of the cooling fluid source 580, such that it functions as a cooling fluid output tube, and one or more of the second tube 584b, the third tube 584c, and the fourth tube 584d may be fluidly coupled to the cooling fluid source 580 instead of the exhaust apparatus 582 such that it functions as a cooling fluid input tube.

[00122] In embodiments, just one of the plurality of tubes 578 may be fluidly coupled to the cooling fluid source 580 such that there is just one cooling fluid input tube, and at least one of the remaining ones of the plurality of tubes 578 is closed. In some of these embodiments, the remaining ones of the plurality of tubes 578 that are not closed may be fluidly coupled to the exhaust apparatus 582. However, in other embodiments, all of the plurality of tubes 578 that are not connected to the cooling fluid source 580 may be fluidly connected to the exhaust apparatus 582 and each includes a valve for selectively opening or closing its lumen.

[00123] In the illustrated embodiment, the second tube 584b, the third tube 584c, and the fourth tube 584d each may include a valve 586b, 586c, 586d operable to open or close the lumen associated therewith and thereby regulate access to the exhaust apparatus 582. Each of the valves 586b, 586c, 586d may be connected to a controller, such as the controller 470 described above, such that opening and closing of the valves 586b, 586c, 586d may be controlled. Also, in embodiments where any one or more of the second tube 584b, the third tube 584c, and the fourth tube 584d are fluidly connected to the cooling fluid source 580, the valve 586b, 586c, 586d associated therewith would similarly operate to regulate input of the cooling fluid into the internal cavity 572 from the cooling fluid source 580.

[00124] Also in the illustrated embodiment, the first tube 584a includes a valve 586a operable to open or close the lumen associated therewith and thereby regulate access to the cooling fluid source 580 such that input of the cooling fluid into the internal cavity 572 may be regulated. The valve 586a may be similarly connected to a controller, such as the controller 470 described above, such that opening and closing of the valve 586a may be controlled. In embodiments where the first tube 584a is in communication with the exhaust apparatus 582, the valve 586a may be operable to open or close the lumen of the first tube 584a and thereby regulate access to the exhaust apparatus 582.

[00125] While the one or more of the valves 586a, 586b, 586c, 586d may be configured to open or close the lumen associated therewith, any one of them may also each be configured to partially close the associated lumen to thereby throttle input flow of cooling fluid into the internal cavity 572 or throttle output flow of cooling fluid from the internal cavity 572, and thereby further control the heat profile formed in the slot block 204 during operation. In some embodiments, one of the plurality of tubes 578 (e.g., the first tube 584a) may be fluidly connected to the cooling fluid source 580 and the remaining ones of the plurality of tubes 578 (e.g., second tube 584b, the third tube 584c, and the fourth tube 584d) maybe fluidly connected to the exhaust apparatus 582 but the valves associated therewith (e.g., the valves 586b, 586c, 586d) are partially open or partially closed. In one of these embodiments, the valve 586d of the fourth tube 584d may be open to a greater degree than the valve 586b of the second tube 584b, and the valve 586c of the third tube 584c may be open to a degree in between the valves 586b, 586d, such that the flow pattern of the cooling fluid within the internal cavity 572 and the dwell time that it remains in various regions of the internal cavity 572 may be controlled. Thus, it is possible to control the amount of cooling fluid exiting the internal cavity 572 through the second tube 584b, the third tube 584c, and the fourth tube 584d, and, as a result, heat extraction from within the internal cavity 572 may be adjusted. For example, if the valves 586c, 586d are closed, cooling fluid input through the first tube 584a will only be evacuated through the second tube 584b, and heat extraction within the internal cavity 572 would be focused at a region therein that is between the first tube 584a and the second tube 584b; however, if the valves 586b, 586c were closed, cooling fluid would only be evacuated through the fourth tube 584d, and heat extraction within the internal cavity 572 would be focused at a relatively larger region therein, as the cooling fluid would be circulated all around the internal cavity 572 between the first tube 584a and the fourth tube 584d.

[00126] Referring again to FIGS. 2A, 2C, 3A, and 3C, in operation, molten glass 116 flows into the glass delivery device 221 of the glass forming apparatus 200 through the inlet conduit 203. The molten glass 116 flows through the passageway 208 of the glass delivery device 221 and into the slot block 204. The molten glass 116 is shaped by the slot block 204 as the molten glass 116 passes through the slot orifice 206 and is discharged from the slot block 204 as a glass ribbon 123 in the flow direction 126. In embodiments, heat extraction assemblies 400 (one depicted in FIG. 2A) may be coupled to corresponding channels 201 formed in the slot block 204 of the glass delivery device 221. Cooling fluid from the cooling fluid source 420 may be directed into the inner lumen 413 of the inner tube 410 (FIG. 3C) of each heat extraction assembly 400 (FIG. 3 A) such that the cooling fluid flows into a corresponding channel 201 in the slot block 204 (FIG. 2C). As the molten glass 116 flows through the slot orifice 206, heat is transferred from the molten glass 116 into the material of the slot block 204. The cooling fluid from the cooling fluid source 420 that is introduced into the channels 201 extracts heat from the material of the slot block 204 around the channels 201 and, hence, from the molten glass 116 of the glass ribbon 123 formed in the slot orifice 206. The cooling fluid introduced into the channels 201 of the slot block 204 (now heated by interaction with the material of the slot block 204) is exhausted through the exhaust channel 411 between the inner tube 410 and the outer tube 402 of the heat extraction assemblies 400. The heated cooling fluid is discharged from the exhaust channel 411 into the internal channel 432 of the housing 430 of the heat extraction assemblies 400, and exhausted from the internal channel 432 through the exhaust manifold 434, thereby extracting heat from the slot block 204 of the glass forming apparatus 200, as well as extracting heat from the glass ribbon 123 shaped by the slot block 204 of the glass forming apparatus 200.

[00127] As noted herein, the amount of heat extracted from the material of the slot block 204 and the glass ribbon 123 formed thereby may be controlled by a position at which the outer tube 402 of the heat extraction assemblies 400 is affixed relative to the channel 201 corresponding therewith. When coupling the outer tube 402 to the channel 201, the distal end 404 of the outer tube 402 may be affixed to the bottom surface 202 of the slot block 204 over the open end 320 of the channel 201, such that the cooling fluid may directly contact and interact with substantially all of the surface area within the channel 201, or the distal end 404 of the outer tube 402 may be at least partially inserted into the channel 201 and affixed therein, such that the outer tube 402 covers at least some of the surface area within the channel 201 and thereby inhibits the cooling fluid from directly contacting and interacting with that covered surface area of the channel 201. Also, the amount of heat extracted from the material of the slot block 204 and the glass ribbon 123 may be controlled by adjusting a position of the inner tube 410 of the heat extraction assemblies 400 in the corresponding channels of the slot block 204. For example, as noted herein, the coarse and fine adjustments of the heat extraction assemblies 400 may facilitate inserting the inner tube 410 farther into a corresponding channel 201 or withdrawing the inner tube 410 from a corresponding channel 201. Inserting the inner tube 410 farther into a corresponding channel 201 may focus injection of the cooling fluid on the closed end 322 of the channel 201, such that heat extraction is greatest at the closed end 322 of the channel 201, which may help produce a temperature gradient within the material surrounding the channel 201. Conversely, withdrawing the inner tube 410 from the corresponding channel 201 may diffuse the injection of cooling fluid over a relatively larger surface area of the channel 201, such that the cooling fluid more uniformly contacts the surface area of the channel 201, which may help create a more uniform temperature distribution in the material surrounding the channel 201. Also, because the distance between the distal end 412 of the inner tube 410 and the closed end 322 of the channel 201 impacts back pressure within the heat extraction assembly 400, and back pressure may in turn alter the flow rate of the cooling fluid and dispersion of the cooling fluid, the coarse and fine adjustments of the heat extraction assemblies 400 may also be utilized to position the inner tube 410 as needed to mitigate effects of back pressure. Accordingly, the amount of heat extracted from the material of the slot block 204 (and the glass ribbon 123 formed with the slot block 204) may be controlled and, in turn, instabilities in the glass ribbon 123 mitigated by localized heat extraction.

[00128] In embodiments, the position of the distal end 404 of the outer tube 402 within the channel 201 is set, then the position of the distal end 412 of the inner tube 410 may be adjusted relative to the closed end 322 of the channel 201, and then molten glass 116 is run through the glass forming apparatus 200 to form the glass ribbon 123. During this formation, the cooling fluid temperature sensor 426 measures a temperature of the cooling fluid supplied to the inner tube 410 and the exhaust temperature sensor 460 measures a temperature of the cooling fluid in the exhaust manifold 434, and the controller 470 calculates heat extraction in the slot block 204 based on the temperature data received from the cooling fluid temperature sensor 426 and the exhaust temperature sensor 460. If the calculated heat extraction is not equal to a target heat extraction, the formation may be stopped and the position of the inner tube 410 relative to the channel 201 may be finely adjusted to thereby alter the heat extraction in the channel 201. Alternatively, if the controller 470 determines that the calculated heat extraction in the channel 201 departs from the target heat extraction, the controller 470 may cause the cooling fluid source 420 to adjust the flow rate of the cooling fluid to thereby increase or decrease the heat extraction from the corresponding channel 201 until the calculated heat extraction reaches the target heat extraction. In embodiments, if the controller 470 determines that the glass ribbon 123 exhibits sheet width variations based on feedback from the glass ribbon sensor 472, the controller 470 will cause the cooling fluid source 420 to adjust the flow of the cooling fluid, based on feedback from the cooling fluid temperature sensor 426 and the exhaust temperature sensor 460, to thereby control heat extraction and stabilize the glass ribbon 123.

Example

[00129] The embodiments described herein will be further clarified by the following examples.

EXAMPLE 1

[00130] Referring to FIGS. 2A and 2B, testing was conducted on the slot block 204 to determine if heat extraction would be improved by using the heat extraction assembly 400 to inject cooling fluid into the at least one channel 201. The testing demonstrated that embodiments of the present disclosure, which improve thermal coupling at the interface where heat transfer from the slot block 204 occurs and inhibit oxidation of the slot block 204, reduce stability issues and sheet width variation in the glass ribbon 123 such that the glass ribbon 123 exhibits improved dimensional characteristics.

[00131] The locations at which the plurality of channels are formed in the slot block 204, as shown in FIG. 2B, were initially identified as possible channel locations based on the best performance of conventional water-cooled fingers 150, 152, thermal modeling, and selected offset positions. Channels 201a, 201c were selected (hereinafter, the “selected channels”) for testing. Channel 201a is offset from the comer radius axis 244, toward the thickness axis 214’, by 25 mm. Similarly, the channel 201c is offset from the comer radius axis 246, toward the thickness axis 214’, by 25 mm. In the test, each of the selected channels was formed with an inner diameter of about 6 mm and with a length L of about 8 mm. Each of the selected channels was oriented at about a 45 degree angle with the vertical dimension in the X-Z plane, such that the distance 312 between the closed end 322 of each of the selected channels and the bottom surface 202 was equal to about 5 mm. Each of the selected channels was formed in the bottom surface 202 of the slot block 204 at a midpoint between the second side 232 of the peripheral side wall 216 and the second inner wall 272 of the slot orifice 206. Further, a first heat extraction assembly 400 was coupled to the channel 201a and a second heat extraction assembly 400 was coupled to the channel 201c. Also during the test, viscosity of the glass ribbon 123 during glass forming was around 100 kilopoise, the mass flow rate of the molten glass 116 was around 10 kg/hr, and the cooling fluid was introduced into the channels at various rates as described below.

[00132] FIG. 6 is a chart showing a relationship between the flow rate of cooling fluid and the width of the glass ribbon 123. Testing was conducted with cooling fluid flow rates increasing from 0 slpm. As can be seen in FIG. 6, the width W of the glass ribbon 123 increased as the flow rate of the cooling fluid into the channels 201a, 201c was increased. This testing further demonstrated that the width W of the glass ribbon 123 increased beyond what was capable using the water-cooled fingers 150, 152, under similar forming conditions, as indicated by line 600.

[00133] FIG. 7 is a chart showing the standard deviation of the position of the left edge of the glass ribbon and the position of the right edge of the glass ribbon when subjected to different flow rates of cooling fluid. As can be seen from FIG. 7, deflection of the glass ribbon 123 was reduced significantly by increasing the flow rate of cooling fluid in the channels 201a, 201c in the slot block 204. The “baseline” case was conducted without any edge cooling (i.e., without the water-cooled fingers 150, 152 and without introducing cooling fluid into any of the channels 201 formed in the slot block 204), and then Case 1, Case 2, Case 3, and Case 4 were each conducted with cooling fluid being introduced into the channels 201 at increasing flow rates. In particular, the flow rate of the cooling fluid was increased from Case 1 to Case 4, with Case 1 having the lowest flow rate and Case 4 having the highest flow rate, and then, after Case 4 was conducted, Case 2 was repeated once more. An increase in the flow rate of cooling fluid within the channels 201a, 201c reduced ribbon deflection significantly, and represented an improvement from the best standard deviation achieved utilizing water-cooled fingers 150, 152, as indicated by line 700.

[00134] FIG. 8 is a chart showing the relationship between sheet width variation of the glass ribbon 123 and the rate at which cooling fluid was directed into the channels 201a, 201c in the slot block 204. Initially, no cooling fluid (in this case, air) was provided to the channels 201a, 201c in the slot block 204 (see “No Air Flow” in FIG. 8). The speed at which the glass ribbon was discharged from the slot block 204 remained constant and, after 1 hour of operation, a flow of air was introduced into the channels 201 a, 201 c (see “Air Flow # 1” in FIG. 8) to extract heat from the slot block 204. Then, after another hour of operation, the flow rate at which the air was introduced into the channels 201a, 201c was doubled (see “Air Flow #2” in FIG. 8) to increase heat extraction from the slot block 204. As shown in FIG. 8, increasing the flow rate of cooling fluid in the channels 201a, 201c decreased the standard deviation of the width W of the glass ribbon 123 from 1.4% (“No Air Flow”) to 0.5 % (“Air Flow #2”). Thus, FIG. 8 demonstrates increasing heat extraction by increasing the flow rate of the cooling fluid improves sheet width variation.

EXAMPLE 2

[00135] Because the overall width W of the glass ribbon 123 is impacted by the amount of heat extraction from the glass ribbon 123 through the slot block 204, as well as the location of the channels 201 relative to the slot comer radii of the slot orifice 206, as represented by the comer radius axes 244, 246, an increase in glass viscosity on the edges 123a, 123b due to heat extraction reduces the amount of attenuation in the width W of the glass ribbon 123. However, if the channels 201 are too close to the slot comer radii, then the width of the slot orifice 206 is effectively reduced. In this example, thermal modeling was utilized to identify optimal locations for the channels in terms of the width W of the glass ribbon 123. FIG. 9 is a chart showing thermal modeling calculations for channel locations relative to the corner radius of the slot orifice 206. In particular, FIG. 9 shows thermal modeling results for six different channel positions (i.e., Curve 1, Curve 2, Curve 3, Curve 4, Curve 5, and Curve 6), where each successive curve was based on a channel position that increased by 10 mm from the channel position of the prior curve. As depicted in FIG. 9, varying the position of the channels 201 affects the width W of the glass ribbon 123.

[00136] The heat extraction assemblies for glass forming apparatuses described herein may be used to control or mitigate sheet width variation and ribbon deflection, and thereby improve slot draw ribbon performance, by providing localized heat extraction within channels formed in the slot block at locations proximate to the slot orifice. The heat extraction assemblies inject cooling fluid into the channels, which improves thermal coupling between the heat extraction assemblies and the slot block and improves performance. Further, the channels may be formed in the slot block at fixed locations, such that the heat extraction assemblies may be consistently positioned at the fixed locations within the slot block, such that the point of heat extraction will remain constant over time. Also, after being affixed to the slot block, the heat extraction assemblies may be accurately adjusted into a desired position within the channel, and such adjustments may be repeated with precision during subsequent operations. Moreover, utilization of the cooling fluid within the channels prevents or mitigates formation of oxidation within the channels, and thereby maintains heat transfer at the surface of the channel for the duration of the life span of the slot block. Even further, the heat extraction assemblies may be controlled to stabilize the glass ribbon and/or to maintain or adjust heat extraction in real time.

[00137] 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.

Claims

What is claimed is:

1 . A glass forming apparatus comprising: a glass delivery device comprising a slot block through which molten glass flows and is formed into a glass ribbon as it exits a slot orifice of the slot block, the slot block comprising a vertical dimension corresponding with a flow direction of the molten glass, a width dimension orthogonal to the vertical dimension, a thickness dimension orthogonal to the vertical dimension and the width dimension, and a plurality of channels formed therein at positions proximate to the slot orifice; and a heat extraction assembly comprising: an outer tube having a distal end and a proximal end, the distal end of the outer tube connected to one of the plurality of channels; an inner tube extending within an outer lumen of the outer tube, the inner tube comprising a distal end and a proximal end and positioned within the outer lumen of the outer tube such that the distal end of the inner tube is positioned proximate to the distal end of the outer tube; a cooling fluid source fluidly coupled to the inner tube and configured to supply a cooling fluid to an inner lumen of the inner tube; and an exhaust manifold fluidly coupled to the outer lumen of the outer tube and configured to exhaust the cooling fluid from an exhaust channel defined between an inner surface of the outer tube and an outer surface of the inner tube .

2. The glass forming apparatus of claim 1, further comprising a housing defining an internal channel, wherein: the outer tube is connected to the housing such that the outer lumen of the outer tube is in fluid communication with the internal channel of the housing; the exhaust manifold is fluidly coupled to the internal channel of the housing such that an exhaust lumen of the exhaust manifold is in fluid communication with the internal channel of the housing; and the inner tube extends at least partially through the internal channel of the housing.

3. The glass forming apparatus of claim 2, wherein: the housing comprises a connector slideably positioned within the housing and comprising an inner passageway; and the inner tube extends through the inner passageway of the connector and is coupled to the connector, whereby translating the connector relative to the housing adjusts a spacing between the distal end of the inner tube and the distal end of the outer tube.

4. The glass forming apparatus of claim 3, further comprising a set screw threadably inserted into the housing, the set screw configured to lock the connector to the housing and inhibit sliding of the connector upon rotation of the set screw in a first direction.

5. The glass forming apparatus of claim 3, wherein the inner tube is threadably coupled to the connector, whereby rotation of the inner tube in the connector adjusts the spacing between the distal end of the inner tube and the distal end of the outer tube.

6. The glass forming apparatus of claim 1 , wherein one or more of the plurality of channels comprises an insulating insert disposed therein, the insulating insert comprising at least one opening through which material of the slot block proximate the slot orifice is exposed to enhance heat extraction from the material.

7. The glass forming apparatus of claim 6, wherein the at least one opening of the insulating insert faces a bottom side of the slot block through which the glass ribbon exits the slot orifice.

8. The glass forming apparatus of claim 1, further comprising: an exhaust temperature sensor operably coupled to the exhaust manifold configured to measure an output temperature of cooling fluid in the exhaust manifold; and a cooling fluid temperature sensor operatively coupled to the cooling fluid source configured to measure an input temperature of the cooling fluid supplied to the inner tube.

9. The glass forming apparatus of claim 8, further comprising a controller operatively connected to the cooling fluid temperature sensor and the exhaust temperature sensor, the controller programmed to calculate heat extraction at the slot block based on the output temperature of the cooling fluid in the exhaust manifold and the input temperature of the cooling fluid supplied by the cooling fluid source.

10. The glass forming apparatus of claim 9, wherein the controller is operable to adjust a flow rate of cooling fluid supplied by the cooling fluid source based on the calculated heat extraction.

11. The glass forming apparatus of claim 10, further comprising a glass ribbon sensor configured to measure a width of the glass ribbon exiting the slot orifice, the controller operatively connected to the glass ribbon sensor and operable to adjust the flow rate of cooling fluid supplied by the cooling fluid source based on the width of the glass ribbon as measured by the glass ribbon sensor.

12. The glass forming apparatus of claim 1, wherein an insulating sleeve is disposed over at least a portion of the outer tube.

13. The glass forming apparatus of claim 1, further comprising a glass ribbon sensor configured to measure a width of the glass ribbon exiting the slot block.

14. The glass forming apparatus of claim 13, further comprising a controller operatively connected to the cooling fluid source and the glass ribbon sensor, the controller operable to adjust a flow rate of cooling fluid supplied by the cooling fluid source based on the width of the glass ribbon as measured by the glass ribbon sensor.

15. The glass forming apparatus of claim 1 , wherein at least one of the plurality of channels extends in a plane defined by the vertical dimension and the width dimension, and a length of the at least one of the plurality of channels is parallel with the vertical dimension.

16. The glass forming apparatus of claim 1, wherein at least one of the plurality of channels extends in a plane defined by the vertical dimension and the width dimension, and a length of the at least one of the plurality of channels is non-parallel with the vertical dimension.

17. The glass forming apparatus of claim 1, wherein at least one of the plurality of channels extends in a plane defined by the width dimension and the thickness dimension, and a length of the at least one of the plurality of channels is parallel with the thickness dimension.

18. The glass forming apparatus of claim 1 , wherein at least one of the plurality of channels extends in a plane defined by the width dimension and the thickness dimension, and a length of the at least one of the plurality of channels is non-parallel with the thickness dimension.

19. The glass forming apparatus of claim 1, wherein the cooling fluid comprises an inert gas.

20. The glass forming apparatus of claim 1, wherein the distal end of the outer tube is affixed to the slot block.

21. A glass forming apparatus comprising: a glass delivery device comprising a slot block through which molten glass flows and is formed into a glass ribbon as it exits an orifice of the slot block, the slot block comprising a vertical dimension corresponding with a flow direction of the molten glass, a width dimension orthogonal to the vertical dimension, a thickness dimension orthogonal to the vertical dimension and the width dimension, and an internal cavity positioned proximate the orifice of the slot block, at least one inlet port in fluid communication with the internal cavity, and at least one outlet port in fluid communication with the internal cavity; and a heat extraction assembly comprising: a cooling fluid input tube connected to the at least one inlet port such that an inner lumen of the cooling fluid input tube is in fluid communication with the internal cavity; a cooling fluid source fluidly coupled to the cooling fluid input tube and configured to supply cooling fluid to the inner lumen of the cooling fluid input tube and the internal cavity; and a cooling fluid output tube connected to the at least one outlet port such that an inner lumen of the cooling fluid output tube is in fluid communication with the internal cavity.

22. The glass forming apparatus of claim 21, wherein the at least one inlet port comprises a single inlet port.

23. The glass forming apparatus of claim 22, wherein the at least one outlet port comprises a single outlet port.

24. The glass forming apparatus of claim 22, wherein the at least one outlet port comprises a plurality of outlet ports and the cooling fluid output tube comprises a plurality of cooling fluid output tubes that each correspond with one of the plurality of outlet ports.

25. The glass forming apparatus of claim 24, wherein at least one of the plurality of cooling fluid output tubes is closed.

26. The glass forming apparatus of claim 24, wherein each of the plurality of cooling fluid output tubes comprises a valve configured to control a flow of cooling fluid from each of the plurality of cooling fluid output tubes.