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Patent Searching and Data


Title:
GLASS MANUFACTURING APPARATUS AND METHODS
Document Type and Number:
WIPO Patent Application WO/2016/048815
Kind Code:
A1
Abstract:
A glass manufacturing apparatus includes a forming device and an enclosure including a float bath. A plurality of rollers are arranged at least partially within the enclosure and are configured to draw a glass ribbon from the forming device, through the enclosure, and over the float bath along a draw path. The glass manufacturing apparatus further includes a thermal device configured to selectively control a local thickness of the glass ribbon at a plurality of discrete locations of the glass ribbon. A method of manufacturing a glass ribbon includes drawing a glass ribbon over a float bath within an enclosure and selectively controlling a local thickness of at least one of a plurality of discrete locations of the glass ribbon within the enclosure.

Inventors:
COOK GLEN BENNETT (US)
JOUBAUD LAURENT (FR)
NIKULIN ILIA ANDREYEVICH (US)
WELLES ANDREW VOSS (US)
Application Number:
PCT/US2015/050876
Publication Date:
March 31, 2016
Filing Date:
September 18, 2015
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
CORNING INC (US)
International Classes:
C03B18/02; C03B18/18
Domestic Patent References:
WO2011066064A22011-06-03
WO2014082000A12014-05-30
WO2011047008A12011-04-21
Foreign References:
US20140182339A12014-07-03
US20140174130A12014-06-26
US20040261458A12004-12-30
Attorney, Agent or Firm:
ABLE, Kevin M (Intellectual Property DepartmentSP-Ti-03-0, Corning New York, US)
Download PDF:
Claims:
CLAIMS

What is claimed is:

1. A glass manufacturing apparatus comprising:

a forming device;

an enclosure comprising a float bath;

a plurality of rollers arranged at least partially within the enclosure, wherein the plurality of rollers are configured to draw a glass ribbon from the forming device, through the enclosure, and over the float bath along a draw path; and

a thermal device configured to selectively control a local thickness of the glass ribbon defined primarily by glass between a first major surface and a second major surface of the glass ribbon at a plurality of discrete locations of the glass ribbon.

2. The glass manufacturing apparatus of claim 1, wherein, at each of the plurality of discrete locations, the thermal device is configured to selectively increase a local temperature of at least one of the plurality of discrete locations of the glass ribbon, and to selectively decrease a local temperature of the at least one of the plurality of discrete locations of the glass ribbon.

3. The glass manufacturing apparatus of claim 1, further comprising:

a controller configured to operate the thermal device to selectively control the local thickness of the glass ribbon at each of the plurality of discrete locations.

4. The glass manufacturing apparatus of claim 3, wherein the controller is configured to operate the thermal device based on a measurement of at least one of a thickness of the glass ribbon and a thickness of a glass sheet cut from the glass ribbon, wherein the measured thickness is defined primarily by glass between the first major surface and the second major surface of the glass ribbon.

5. The glass manufacturing apparatus of claim 1, wherein the thermal device comprises a plurality of thermal elements each of which corresponds to a respective one of the plurality of discrete locations, wherein the plurality of thermal elements are arranged along a thermal path extending transverse to the draw path.

6. The glass manufacturing apparatus of claim 1, wherein the plurality of rollers comprises:

an upstream pair of rollers configured to contact upstream edge portions of the glass ribbon; and

a downstream pair of rollers spaced from the upstream pair of rollers along the draw path and configured to contact downstream edge portions of the glass ribbon,

wherein at least one of the plurality of discrete locations is located at least partially between the upstream pair of rollers and the downstream pair of rollers.

7. The glass manufacturing apparatus of claim 1, wherein at least one of the plurality of discrete locations comprises an area within a range of from about 2 cm2 to about 25 cm2 with respect to a draw plane extending along the draw path.

8. The glass manufacturing apparatus of claim 1, wherein at least a portion of the thermal device is less than 0.25 inches from a draw plane extending along the draw path.

9. The glass manufacturing apparatus of claim 1, wherein the thermal device comprises a plurality of tubes through which a fluid is configured to circulate, wherein the circulating fluid is configured to transfer heat to selectively change a local temperature of the glass ribbon.

10. The glass manufacturing apparatus of claim 9, wherein the plurality of tubes are arranged in a casing, and wherein the plurality of tubes comprise ceramic and the casing comprises silicon carbide.

11. The glass manufacturing apparatus of claim 1 , wherein the thermal device comprises a fluid jet configured to selectively impinge fluid on one or more of the plurality of discrete locations of the glass ribbon.

12. The glass manufacturing apparatus of claim 1, wherein at least a portion of the thermal device is submerged in the float bath.

13. The glass manufacturing apparatus of claim 12, wherein the submerged portion of the thermal device is configured to selectively control a local temperature of the float bath.

14. A method of manufacturing a glass ribbon comprising the steps of:

drawing a glass ribbon over a float bath within an enclosure; and

selectively controlling a local thickness of at least one of a plurality of discrete locations of the glass ribbon within the enclosure, wherein the local thickness is defined primarily by glass between a first major surface and a second major surface of the glass ribbon.

15. The method of claim 14, further comprising the step of controlling a local temperature of the at least one of the plurality of discrete locations to control the corresponding local thickness of the glass ribbon.

16. The method of claim 15, further comprising the step of controlling the local temperature based on a measurement of at least one of a thickness of the glass ribbon and a thickness of a glass sheet cut from the glass ribbon, wherein the measured thickness is defined primarily by glass between the first major surface and the second major surface of the glass ribbon.

17. The method of claim 14, further comprising the step of:

selecting one or more of the plurality of discrete locations based on a

measurement of at least one of a thickness of the glass ribbon and a thickness of a glass sheet cut from the glass ribbon, wherein the measured thickness is defined primarily by glass between the first major surface and the second major surface of the glass ribbon.

18. The method of claim 17, further comprising the step of: controlling a local temperature of each of the selected one or more discrete locations based on the measurement.

19. The method of claim 14, further comprising the step of:

selectively controlling a local temperature of the float bath to selectively control the local thickness of the at least one of the plurality of discrete locations.

20. The method of claim 19, further comprising the step of:

selectively inducing a current in the float bath to selectively control the local temperature of the float bath.

Description:
GLASS MANUFACTURING APPARATUS AND METHODS

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. 62/053386 filed on September 22, 2014, the content of which is relied upon and incorporated herein by reference in its entirety.

TECHNICAL FIELD

[0002] The disclosure relates generally to glass manufacturing apparatus and methods and, more particularly, to glass manufacturing apparatus and methods including a float process.

BACKGROUND

[0003] Glass manufacturing apparatus and methods are used to form a glass ribbon that may be rolled into rolls or separated into glass sheets. The glass ribbon may be used for display and other applications. Glass manufacturing apparatus and methods particular to the float process include a float bath on which the glass ribbon floats and over which the glass ribbon is drawn.

SUMMARY

[0004] The following presents a simplified summary of the disclosure in order to provide a basic understanding of some example aspects described in the detailed description.

[0005] In a first aspect of the disclosure, a glass manufacturing apparatus includes a forming device, an enclosure, a plurality of rollers, and a thermal device. The enclosure includes a float bath and the plurality of rollers are arranged at least partially within the enclosure. The plurality of rollers are configured to draw a glass ribbon from the forming device, through the enclosure, and over the float bath along a draw path. The thermal device is configured to selectively control a local thickness of the glass ribbon defined primarily by glass between a first major surface and a second major surface of the glass ribbon at a plurality of discrete locations of the glass ribbon.

[0006] In one example of the first aspect, at each of the plurality of discrete locations, the thermal device is configured to selectively increase a local temperature of at least one of the plurality of discrete locations of the glass ribbon, and to selectively decrease a local temperature of the at least one of the plurality of discrete locations of the glass ribbon. [0007] In a further example of the first aspect, the glass manufacturing apparatus further includes a controller. The controller is configured to operate the thermal device to selectively control the local thickness of the glass ribbon at each of the plurality of discrete locations. In one example, the controller is configured to operate the thermal device based on a measurement of at least one of a thickness of the glass ribbon and a thickness of a glass sheet cut from the glass ribbon, wherein the measured thickness is defined primarily by glass between the first major surface and the second major surface of the glass ribbon.

[0008] In another example of the first aspect, the thermal device includes a plurality of thermal elements each of which corresponds to a respective one of the plurality of discrete locations. In one example, the plurality of thermal elements are arranged along a thermal path extending transverse to the draw path.

[0009] In yet another example of the first aspect, the plurality of rollers include an upstream pair of rollers and a downstream pair of rollers. The upstream pair of rollers are configured to contact upstream edge portions of the glass ribbon. The downstream pair of rollers are spaced from the upstream pair of rollers along the draw path and are configured to contact downstream edge portions of the glass ribbon. In one example, at least one of the plurality of discrete locations is located at least partially between the upstream pair of rollers and the downstream pair of rollers.

[0010] In still another example of the first aspect, at least one of the plurality of discrete locations includes an area within a range of from about 2 cm 2 to about 25 cm 2 with respect to a draw plane extending along the draw path.

[0011] In still another example of the first aspect, at least a portion of the thermal device is less than 0.25 inches from a draw plane extending along the draw path.

[0012] In still another example of the first aspect, the thermal device includes a plurality of tubes through which a fluid is configured to circulate. The circulating fluid is configured to transfer heat to selectively change a local temperature of the glass ribbon. In one example, the plurality of tubes are arranged in a casing. In another example, the plurality of tubes include ceramic and the casing includes silicon carbide.

[0013] In still another example of the first aspect, the thermal device includes a fluid jet configured to selectively impinge fluid on one or more of the plurality of discrete locations of the glass ribbon. [0014] In still another example of the first aspect, at least a portion of the thermal device is submerged in the float bath. In one example, the submerged portion of the thermal device is configured to selectively control a local temperature of the float bath.

[0015] The first aspect may be provided alone or in combination with one or any combination of the examples of the first aspect discussed above.

[0016] In a second aspect of the disclosure, a method of manufacturing a glass ribbon includes drawing a glass ribbon over a float bath within an enclosure. The method further includes selectively controlling a local thickness of at least one of a plurality of discrete locations of the glass ribbon within the enclosure, wherein the local thickness is defined primarily by glass between a first major surface and a second major surface of the glass ribbon.

[0017] In one example of the second aspect, the method further includes controlling a local temperature of the at least one of the plurality of discrete locations to control the corresponding local thickness of the glass ribbon. In one example, controlling the local temperature is based on a measurement of at least one of a thickness of the glass ribbon and a thickness of a glass sheet cut from the glass ribbon, wherein the measured thickness is defined primarily by glass between the first major surface and the second major surface of the glass ribbon.

[0018] In another example of the second aspect, the method further includes selecting one or more of the plurality of discrete locations based on a measurement of at least one of a thickness of the glass ribbon and a thickness of a glass sheet cut from the glass ribbon, wherein the measured thickness is defined primarily by glass between the first major surface and the second major surface of the glass ribbon. In one example, the method still further includes controlling a local temperature of each of the selected one or more discrete locations based on the measurement.

[0019] In yet another example of the second aspect, the method further includes selectively controlling a local temperature of the float bath to selectively control the local thickness of the at least one of the plurality of discrete locations. In one example, the method still further includes selectively inducing a current in the float bath to selectively control the local temperature of the float bath.

[0020] The second aspect may be provided alone or in combination with one or any combination of the examples of the second aspect discussed above. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] These and other aspects are better understood when the following detailed description is read with reference to the accompanying drawings, in which:

[0022] FIG. 1 illustrates a side view of an example glass manufacturing apparatus in accordance with the disclosure;

[0023] FIG. 2 illustrates a top view of a portion of the example glass manufacturing apparatus along line 2-2 of FIG. 1;

[0024] FIG. 3 illustrates a front cross-sectional view of a first example thermal device;

[0025] FIG. 4 illustrates an enlarged view of a region 4 of the first example thermal device of FIG. 3;

[0026] FIG. 5 illustrates a front cross-sectional view of a second example thermal device;

[0027] FIG. 6 illustrates an enlarged view of a region 6 of the second example thermal device of FIG. 5;

[0028] FIG. 7 illustrates a front cross-sectional view of a third example thermal device; and

[0029] FIG. 8 illustrates an enlarged view of a region 8 of the third example thermal device of FIG. 7.

DETAILED DESCRIPTION

[0030] Examples will now be described more fully hereinafter with reference to the accompanying drawings in which example embodiments are shown. Whenever possible, the same reference numerals are used throughout the drawings to refer to the same or like parts. However, aspects may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

[0031] Referring to FIG. 1, an example glass manufacturing apparatus 101 is provided with various example features that may be used either alone or in combination to manufacture a glass ribbon 105. As shown, the glass manufacturing apparatus 101 may comprise a melting tank 107, a forming device 103, a float tank 110 with an enclosure 112 that at least partially encloses the tank 110, an annealer 115, a cool-down region 120, and a lift-off region 125.

[0032] In one example, the melting tank 107 comprises a furnace wherein glass batch materials are introduced as shown by arrow 121. The glass batch materials can be pre- mixed, in some examples, and can be added to the melting tank 107 continuously or intermittently. Once in the melting tank 107, the glass batch materials are heated and melted to form a molten glass 123. In one example, the molten glass 123 can flow directly from the melting tank 107 over the forming device 103 into the float tank 110. In further examples, the molten glass 123 can be treated or conditioned to remove impurities, bubbles, or other inclusions prior to forming the glass ribbon 105 in the float tank 110. Various forming devices may be used to produce the glass ribbon 105 in accordance with aspects of the disclosure. For example, as shown in FIG. 2 (with the enclosure 112 not shown for purposes of clarity), the forming device 103 can comprise a spout or a ceramic lipstone over which the molten glass 123 flows into the float tank 110. As shown in FIG. 2, the glass manufacturing apparatus 101 can form the glass ribbon 105 with a width "W" extending between a first edge portion 105a and a second edge portion 105b of the glass ribbon 105.

[0033] From the float tank 110, the features of which are described more fully below, the glass ribbon 105 can be further drawn or transported through the annealer 115, as shown in FIG. 1. In one example, the annealer 115 comprises a plurality of rollers (not shown) on which the glass ribbon 105 is transported. In another example, the annealer 115 comprises an annealer oven 116, wherein the glass ribbon 105 is cooled. In yet another example, the glass ribbon 105 can be cooled slowly to prevent stresses from building up in the glass ribbon 105. Once through the annealer 115, the glass ribbon 105 can continue to be further drawn or transported through the cool-down region 120. In one example, the glass ribbon 105 continues to cool and harden in the cool-down region 120. Once the glass ribbon 105 has sufficiently cooled, the glass ribbon can be further processed. In one example, the glass ribbon can be trimmed or cut to remove edges of the glass ribbon, which can become marred by rollers or other devices used to draw, stretch, or otherwise manipulate the glass ribbon during the glass manufacturing process. In another example, the glass ribbon 105 can be cut into individual glass sheets 127a, 127b of a predetermined size. In the lift-off region 125, a robotic arm or other device (not shown) can lift the individual glass sheets 127a, 127b and move the individual glass sheets to a different location. For example, the individual glass sheets 127a, 127b can be packaged and/or transferred to a vehicle or other conveyance device (not shown) for transport to a location located at a distance away from the glass manufacturing apparatus 101. In still other examples, the individual glass sheets 127a, 127b can be stored or stacked for future use. In yet another example, the glass ribbon 105 is not cut into individual glass sheets; rather, the glass ribbon 105 can remain substantially continuous over a period of time and can be, for example, rolled into a storage roll (not shown).

[0034] In still another example, the float tank 110 can comprise a container or vessel for holding a material, such as a float bath material, (referred to, hereinafter, generally as "a float bath 111"). As shown in FIG. 2, the float bath 111 comprises an upstream end 118 and a downstream end 119, wherein the upstream end 118 is located closer to the forming device 103 than the downstream end 119. In one example the float bath 111 comprises a molten material such as molten or liquid tin. In still other examples, the float bath 111 can include lead or other alloys with a relatively low melting point. In yet another example, the float bath 111 may form a shallow pool in the float tank 110. Turning back to FIG. 1, the float bath 111 can be provided in the float tank 110 and surrounded by the enclosure 112 which can include an atmosphere 113 comprising a gaseous medium. In one example, the atmosphere 113 is a reducing atmosphere in which oxidation is prevented by removal of oxygen and other oxidizing gases or vapors. In another example, the atmosphere 113 can be heated to control a temperature of the atmosphere 113 within the enclosure 112.

[0035] As further shown in FIG. 2, when the glass ribbon 105 leaves the forming device 103 and enters the float tank 110, the glass ribbon 105 can, for example, pour onto a surface of the float bath 111 on which the glass ribbon 105 can float. In one example, based on at least the force of gravity acting on the glass ribbon 105 in a direction opposite a resistive force of a surface tension of the float bath 111, the glass ribbon 105 can naturally smooth or spread out within the float tank 110 as the glass ribbon 105 floats on the surface of the float bath 111. This natural smoothing or spreading of the glass ribbon 105 can aid in the production of a thin glass ribbon.

[0036] In another example, mechanical devices can impart forces on the glass ribbon 105 to further manipulate or control various characteristics, such as a width, a length, and/or a thickness, of the glass ribbon 105. For example, the glass manufacturing apparatus 101 can include a plurality of rollers 102 configured to help draw the glass ribbon 105 from the forming device 103 into the float tank 110 and through the enclosure 112 from the upstream end 118 to toward the downstream end 119 along a draw path 104. In one example, the plurality of rollers 102 can be arranged at least partially within the enclosure 112 to help stretch the glass ribbon 105 into a flat sheet as the glass ribbon 105 cools. As will be discussed more fully below, a thermal device 150 can also be arranged at least partially within the enclosure 112.

[0037] During the glass manufacturing process, various defects can be introduced into the glass ribbon when, for example, melting the glass batch material to form molten glass or when forming and stretching the glass ribbon using rollers or other devices. The defects can include waviness in the glass ribbon, variations in the thickness of the glass ribbon, and other impurities or undesirable characteristics or imperfections of the glass ribbon. In one example, a variation in thickness can occur based on a variation in a local viscosity of the glass ribbon. The variation in local viscosity of the glass ribbon can occur based on local variations in glass composition and/or variations in a local temperature of the glass ribbon that results in viscous inhomogeneity of the glass ribbon.

[0038] As shown in FIG. 4, the glass ribbon 105 can comprise a first major surface 221 and a second major surface 222 wherein a thickness "t" of the glass ribbon can be defined primarily by glass with an insignificant or no impurities (e.g., bubbles) between the first and second major surfaces 221, 222. In one example, a local oversized thickness at a discrete location of the glass ribbon may be larger than a desired thickness, such as a thickness of adjacent portions of the glass ribbon or a target thickness of the glass ribbon. The local oversized thickness can result primarily from an excess volume of glass between the first major surface 221 of the glass ribbon 105 and the second major surface 222 of the glass ribbon 105 at the discrete location. Indeed, bubbles may be nonexistent or provide a relatively insignificant contribution to the oversized local thickness. Rather, the oversized local thickness is primarily or entirely the result of an excess volume of glass between the first major surface 221 and the second major surface 222 of the glass ribbon 105 at the discrete location.

[0039] In another example, a local undersized thickness at a discrete location of the glass ribbon may be smaller than a desired thickness, such as a thickness of adjacent portions of the glass ribbon or a target thickness of the glass ribbon. The local undersized thickness can result primarily from a deficient volume of glass between the first major surface 221 of the glass ribbon 105 and the second major surface 222 of the glass ribbon 105 at the discrete location. Indeed, bubbles may be nonexistent or provide a relatively insignificant contribution to the undersized local thickness. Rather, the undersized local thickness is primarily or entirely the result of a deficient volume of glass between the first major surface 221 and the second major surface 222 of the glass ribbon 105 at the discrete location.

[0040] In one example, the thermal device 150 is provided in the enclosure 112 to control a local temperature of the glass ribbon which, in turn, can control a corresponding local viscosity of the glass ribbon, which can be used to control a corresponding local thickness of the glass ribbon. The thermal device 150 can be configured to selectively control a local thickness of the glass ribbon 105 defined primarily by glass with an insignificant or no impurities (e.g., bubbles) between the first and second major surfaces 221, 222 at a plurality of discrete locations (e.g. 106a, 106b, 106c) of the glass ribbon 105. In one example, the thermal device 150 can be configured to selectively increase a local temperature of the glass ribbon at one or more of the plurality of discrete locations (e.g. 106a, 106b, 106c). In another example, the thermal device 150 can be configured to selectively decrease a local temperature of the glass ribbon at one or more of the plurality of discrete locations (e.g. 106a, 106b, 106c). In still another example, at each of the plurality of discrete locations (e.g. 106a, 106b, 106c), the thermal device 150 can be configured to selectively increase a local temperature of at least one of the plurality of discrete locations of the glass ribbon, and to selectively decrease a local temperature of the at least one of the plurality of discrete locations of the glass ribbon.

[0041] It is to be understood that the thermal device 150 can be configured to selectively increase, decrease, or maintain a local temperature of the glass ribbon at any one of the plurality of discrete locations of the glass ribbon. For instance, by way of example, the thermal device 150 can be configured to increase a local temperature of a first discrete location (e.g. 106a), decrease a local temperature of a second discrete location (e.g. 106b), and maintain a local temperature of a third discrete location (e.g. 106c). The thermal device 150 can be configured to selectively control a local thickness of the glass ribbon defined primarily by glass with an insignificant or no impurities (e.g., bubbles) between the first and second major surfaces 221, 222 of the glass ribbon 105 at any of the plurality of discrete locations simultaneously or separately as well as at preset intervals in time or at any point in time. [0042] By increasing a local temperature of the glass ribbon, a corresponding local viscosity of the glass ribbon will likewise decrease and, as a result, a local thickness of the glass ribbon will decrease. Increasing a local temperature may be desired to address a local oversized thickness at a discrete location of the glass ribbon. As discussed above, the local oversized thickness can result primarily from an excess volume of glass between the first and second major surfaces 221, 222 of the glass ribbon 105. Increasing the local temperature of the glass ribbon at the discrete location with the local oversized thickness will decrease the local viscosity of the glass ribbon at the discrete location. As a result, the local oversized thickness will be reduced to match adjacent portions of the glass ribbon or approach the target thickness of the glass ribbon as the glass at the discrete location more freely flows, outwardly, thereby reducing the volume of glass at the discrete location.

[0043] Alternatively, by decreasing a local temperature of the glass ribbon, a corresponding local viscosity of the glass ribbon will likewise increase and, as a result, a local thickness of the glass ribbon will increase.

[0044] Decreasing a local temperature may be desired to address a local undersized thickness at a discrete location of the glass ribbon. As discussed above, the local undersized thickness can result primarily from a deficient volume of glass between the first and second major surfaces 221, 222 of the glass ribbon 105. Decreasing the local temperature of the glass ribbon at the discrete location with the local undersized thickness will increase the local viscosity of the glass ribbon at the discrete location. As a result, the local undersized thickness will be increase to match adjacent portions of the glass ribbon or approach the target thickness of the glass ribbon as the glass at the discrete location is relatively restricted from flowing outwardly, thereby increasing the volume of glass at the discrete location.

[0045] Accordingly, in one example, a discrete location of the glass ribbon having a local thickness greater than a desired thickness can be selectively heated to decrease the local viscosity and thus reduce the local thickness, while a discrete location of the glass ribbon having a local thickness less than a desired thickness can be selectively cooled to increase the local viscosity and thus increase the local thickness.

[0046] In still another example, the plurality of rollers 102 can include an upstream pair of rollers 102a configured to contact upstream edge portions of the glass ribbon 105. The plurality of rollers 102 can further include a downstream pair of rollers 102b spaced from the upstream pair of rollers along the draw path 104 and configured to contract downstream edge portions of the glass ribbon 105. In one example, at least one of the plurality of discrete locations (e.g. 106a, 106b, 106c) is located at least partially between the upstream pair of rollers 102a and the downstream pair of rollers 102b. In other examples, the glass manufacturing apparatus 101 can include a third pair of rollers 102c arranged at any location between the upstream pair of rollers 102a and the downstream pair of rollers 102b. In still other examples, the glass manufacturing apparatus 101 can include any number of additional rollers arranged at different locations along the glass ribbon 105. In yet another example, the rollers can draw and stretch the glass ribbon 105 in various directions, including in a direction substantially transverse to the draw path 104. Further, the glass ribbon 105 can also be drawn in a substantially horizontal direction over the float bath 111, such that at least a portion of the glass ribbon 105 floats on the surface of the float bath 111. Still further, the glass ribbon 105 can be drawn in a direction away from the float bath 111 for further processing of the glass ribbon 105.

[0047] In yet another example, the thermal device 150 can include a plurality of thermal elements (e.g. 150a, 150b, 150c) each of which corresponds to a respective one of the plurality of discrete locations (e.g. 106a, 106b, 106c). The plurality of thermal elements (e.g. 150a, 150b, 150c) can be arranged along a thermal path 130 extending transverse to the draw path 104. In other examples, a plurality of thermal devices, each of which includes one or more thermal elements can be arranged at various locations within the enclosure 112. The plurality of thermal devices (examples of which are described more fully below) can be arranged at any location along the draw path 104 and at any location across the width "W" of the glass ribbon 105 to control a local thickness of the glass ribbon defined primarily by glass between the first major surface 221 and the second major surface 222 of the glass ribbon 105 at any one or more discrete locations of the glass ribbon. For example, at any given point in time, all, none, or one or more of the thermal elements of all, none, or one or more of the thermal devices can be configured to operate to control the local thickness of the glass ribbon at any corresponding discrete location of the glass ribbon.

[0048] As further shown in FIG. 2, the glass manufacturing apparatus 101 can further include a controller 140 (e.g., programmable logic controller) configured to (e.g., "programmed to", "encoded to", designed to", and/or "made to") operate the thermal device 150 to selectively control a local thickness of the glass ribbon 105 defined primarily by glass between the first major surface 221 and the second major surface 222 of the glass ribbon 105 at each of the plurality of discrete locations of the glass ribbon 105. In one example, the controller 140 can be configured to operate the thermal device 150 based on a measurement of at least one of a thickness of the glass ribbon and a thickness of a glass sheet cut from the glass ribbon, wherein the thickness is defined primarily by glass between the first and second major surfaces 221, 222. In one example, the thickness can be obtained using an online measurement of a thickness of the glass ribbon 105 as it is being manufactured. The thickness measurement can be a single measurement or a plurality of measurements, for example, corresponding to a measured thickness of the glass ribbon at one or more locations of the glass ribbon. In other examples, the measurement can be obtained at a single instant in time or over a period of time to include, for example, an average thickness of the glass ribbon at one or more locations of the glass ribbon. In still other examples, the measurement can be obtained from one or more individual glass sheets cut from the glass ribbon. Similarly, the measurements obtained from the individual glass sheets can correspond to a thickness at one or more locations of the individual glass sheet. In other examples, the controller 140 can be configured to operate the thermal device 150 based on other factors or variables, including but not limited to various characteristics of the glass ribbon, such as a temperature of the glass ribbon at one or more locations of the glass ribbon.

[0049] One example of the thermal device 150 is shown in FIGS. 3 and 4, where the thermal device 150 includes a plurality of tubes 302 through which a fluid is configured to circulate (as shown by arrows 161, 163, and 164 in FIG. 4). The circulating fluid is configured to transfer heat to selectively change a local temperature of the glass ribbon 105. For example, one or more of the plurality of tubes 302 can circulate a cooling fluid (represented by 161) to transfer (e.g. remove) heat from one or more of a plurality of discrete locations (e.g. 106d) to a different location, away from the discrete location. The one or more of the plurality of tubes 302, as well as different or additional one or more of the plurality of tubes, can also circulate a heating fluid (represented by 163) to transfer (e.g. add) heat to one or more of a plurality of discrete locations (e.g. 106e). The cooling fluid 161 and/or the heating fluid 163 can be recirculated through the thermal device 150 as shown by arrows 164 to transfer heat to control a local temperature of the glass ribbon at any one or more of the plurality of discrete locations. As further shown, the plurality of tubes 302 can be arranged in a casing 303. A selected one or more of the plurality of tubes 302 can be configured to inject the circulating fluid into the casing 303 such that heat can be transferred between the selected locations of the casing 303 and the one or more of the plurality of discrete locations (e.g. 106d, 106e) and/or between the one or more of the plurality of discrete locations (e.g. 106d, 106e) and the casing 303. In one example, the plurality of tubes 302 includes a ceramic material and the casing 303 includes silicon carbide. In other examples, the plurality of tubes 302 and the casing 303 can be spaced apart at fixed intervals to permit recirculation or flow of the atmosphere 113 within the enclosure 112.

[0050] As shown in FIG. 4, at least a portion of the second major surface 222 can be in contact with and float on the surface of the float bath 111. In yet another example, the first major surface 221 can be opposite to and substantially parallel with the second major surface 222. For example, the first major surface 221 can include a surface opposite the second major surface 222, wherein at least a portion of the second major surface 222 is floating on and in contact with the surface of the float bath 111. In one example, at least a portion of the thermal device 150 can be less than 0.635 cm (0.25 inches) from a draw plane (e.g. the first major surface 221 of the glass ribbon 105) extending along the draw path 104 as shown by dimension 223. In another example, at least one of the plurality of discrete locations (e.g. 106a, 106b) can include an area within a range of from about 2 cm 2 to about 25 cm 2 with respect to the draw plane extending along the draw path 104. In other examples, a high resolution of thermal control can be achieved, wherein the high resolution of control includes a length scale in a range from about 2 cm to about 5 cm. In other examples, the refinement or resolution of the discrete locations can include any level of refinement or resolution wherein the thermal device 150 is configured to control a local thickness of the glass ribbon.

[0051] Another example of the thermal device 150 is shown in FIGS. 5 and 6, where the thermal device 150 includes a fluid jet configured to impinge fluid on one or more of the plurality of discrete locations of the glass ribbon 105. The thermal device can comprise a plurality of pipes 502 each of which can selectively direct a fluid to impinge on the glass ribbon as a fluid jet. In one example, the fluid is a cooling fluid that forms a cooling jet 160 that impinges on the glass ribbon to decrease a local temperature of a discrete location (e.g. 106f) of the glass ribbon 105. In another example, the fluid is a reactive fluid that forms a flame 162 that impinges on the glass ribbon to increase a local temperature of a discrete location (e.g. 106g) of the glass ribbon 105. In yet another example, the cooling jet 160 can include a reducing fluid or reducing atmosphere, such as the atmosphere 113, within the enclosure 112. The reducing fluid can include a mixture of N 2 and H 2 or other gas or mixture of gases compatible with the atmosphere 113. In still another example, the flame 162 can be produced by a combustion reaction of a fuel rich fluid (e.g. 0 2 or ambient air). In some examples, the flame 162 can impinge the glass ribbon at a temperature within a range of about 2200 °C to 3200 °C.

[0052] Yet another example of the thermal device 150 is shown in the FIGS. 7 and 8, where at least a portion of the thermal device 150 is submerged in the float bath 111. In one example, the thermal device 150 can be completely submerged in the float bath 111. In another example, the submerged portion is configured to selectively control a local temperature of the float bath 111. The thermal device 150 can include a plurality of probes 702 each of which can include a heating and/or cooling element 165 arranged in a refractory sheath 166. By controlling a temperature of one or more of the probes, a local temperature of the float bath 111 can also be controlled which, in turn, imparts a corresponding change in temperature on one or more of the plurality of discrete locations (e.g. 106h, 106i) of the glass ribbon 105 floating on the float bath 111.

[0053] It is to be understood that the controller 140 can be configured to operate any of the example thermal devices 150 discussed herein, as well as other thermal devices not explicitly described, either alone or in combination. Further, as noted, any of the example thermal devices 150 as well as any features of the example thermal devices can be used either alone or in combination with other example thermal devices and other example features of other example thermal devices, including those not explicitly described herein to control a local thickness of the glass ribbon at one or more of a plurality of discrete locations of the glass ribbon. In other examples, one or more controllers can be configured to operate the thermal devices and to implement a closed loop control system to operate the thermal devices.

[0054] In one example, a method of manufacturing a glass ribbon includes drawing a glass ribbon 105 over a float bath 111 within an enclosure 112. The method includes selectively controlling a local thickness of at least one of a plurality of discrete locations (e.g. 106a, 106b, 106c) of the glass ribbon 105 within the enclosure 112, wherein the local thickness is defined primarily by glass between the first major surface 221 and the second major surface 222. The method can include the step of controlling a local temperature of the at least one of the plurality of discrete locations (e.g. 106a, 106b, 106c) to control a corresponding local thickness of the glass ribbon 105. In one example, controlling the local temperature can be based on a measurement of at least one of a thickness of the glass ribbon and a thickness of a glass sheet cut from the glass ribbon, wherein the measured thickness is defined primarily by glass between the first major surface and the second major surface. In still another example, the method can include selecting one or more of the plurality of discrete locations (e.g. 106a, 106b, 106c) based on a measurement of at least one of a thickness of the glass ribbon and a thickness of a glass sheet cut from the glass ribbon. In one example, the method further includes controlling a local temperature of each of the selected one or more discrete locations (e.g. 106a, 106b, 106c) based on the measurement. In yet another example, the method can include selectively controlling a local temperature of the float bath 111 to selectively control the local thickness of the at least one of the plurality of discrete locations (e.g. 106a, 106b, 106c). In still another example, the method can further include selectively inducing a current in the float bath 111 to selectively control the local temperature of the float bath 111.

[0055] It will be apparent to those skilled in the art that various modifications and variations can be made to the present disclosure without departing from the spirit and scope of the subject matter claimed.