Patent Publication Number: US-2020290916-A1

Title: Systems and methods for processing thin glass ribbons

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of priority under 35 U.S.C. § 119 of U.S. Provisional Application Ser. No. 62/579,543 filed Oct. 31, 2017 and U.S. Provisional Application Ser. No. 62/618,259 filed Jan. 17, 2018, the content of each are relied upon and incorporated herein by reference in their entirety. 
    
    
     BACKGROUND 
     Field 
     The present disclosure generally relates to systems and methods for processing a glass ribbon. More particularly, it relates to systems and methods for handling a glass ribbon as part of the manufacture of thin glass sheets from a moving glass ribbon. 
     Technical Background 
     Production of glass sheets typically involves producing a glass ribbon from a molten glass material, and then cutting or separating individual glass sheets from the glass ribbon. Various techniques are known for producing the glass ribbon. For example, with a down-draw process (e.g., fusion draw process), the ribbon is drawn downward, typically from a forming body. Other glass making processes include, for example, float, up-draw, slot-style and Fourcault&#39;s-style processes. In yet other examples, the glass ribbon can be temporarily stored in roll form, and later unwound for subsequent cutting or separation of individual glass sheets. 
     To meet the demands of many end use applications, continuing efforts have been made to produce thinner glass sheets (e.g., about 1 millimeter (mm) or less). As the thickness of the glass ribbons from which the glass sheets are formed becomes thinner, they are also more susceptible to warp (or flatness deviations) and other concerns (such as surface damage that may be imparted during the process steps to provide a thinner glass ribbon). Warp can occur in one or more of the width or length direction of the glass ribbon. During the glass forming process, a glass ribbon is first formed in a viscous state, and is then cooled to a viscoelastic state and finally to an elastic state. With some thin rolled glass formation techniques, the process layout includes transitioning the glass ribbon from a vertical orientation to a horizontal orientation, and then conveying in the horizontal orientation within a controlled cooling environment. When the glass ribbon is thin and still at low viscosity, it can be very easy to generate in-plane local stresses that in turn can induce out-of-plane deformation (e.g., buckling). 
     For example, a typical practice is to convey the glass ribbon on a series of driven rollers. To be viable, there normally is some friction between surface(s) of the glass ribbon and the driven roller in order to impart a driving force and direction. Rollers inherently may not have perfect alignment with the glass ribbon travel direction, and may not have perfectly matched linear velocities. The resulting effects are differential steering and pulling that can induce stresses that may cause deformation. A local deformation can be the result of a local tensile force or compressive stress. In addition to possibly generating some stretching at low viscosities, tensile stresses may also cause local slippage and potentially scratches. 
     As an alternative to driven rollers, air bearings have been considered for glass ribbon transport. In principle, an air bearing surface can serve to prevent direct contact between the hot glass ribbon and a cold tooling surface. In the context of thick glass ribbon transport, available air bearing conveyor devices may address some issues associated with driven roller conveyance. However, with available air bearing conveyor devices, an intrinsic limitation exists at the edges of the air bearing device where the air bearing effect diminishes, resulting in direct contact with a support of the air bearing conveyor device. Local cooling by direct contact can be a distinct concern in the context of thin glass ribbons given the small thermal mass of the glass ribbon and the comparatively large heat transfer generated at the point of contact, potentially resulting in an oscillating condition that materializes in a wavy ribbon edge, as well as other possible forms of deformation in the traveling glass ribbon. 
     Regardless of the source, the deformation(s) described above may become “frozen” in the final product as the glass ribbon cools. A flatter glass ribbon reduces the amount of material that may need to be removed, such as by grinding and/or polishing, to achieve a given final thickness. For example, flatness on the order of 100 micrometers (for a sheet size of about 250 mm×600 mm) may be necessary for some applications. 
     The common practice to minimize warp is to pass the glass ribbon through nip rolls at a location close to the end of the purely viscous regime. Nip rolls are cylindrical and can be set at a fixed gap or at a fixed pinch force. Typically one of the two nip rolls is driven and the other is idle to apply a desired force. Regardless, the mechanical effect applied to the glass ribbon by the nip rolls is essentially unidirectional (a “squeezing” effect) and characterized as a short line or linear mode of contact. For some end use applications, the linear contact applied by the nip rolls alone cannot achieve a desired level of flatness. 
     Accordingly, systems and methods for processing a glass ribbon, for example reducing occurrences of out-of-plane deformation in a glass ribbon, are disclosed herein. 
     SUMMARY 
     Some embodiments of the present disclosure relate to a method for processing a glass ribbon. A glass ribbon is supplied to an upstream side of a conveying apparatus. A pulling force is applied on the glass ribbon at a downstream side of the conveying apparatus. The glass ribbon is supported at first and second support devices along a travel path of the conveying apparatus from the upstream side to the downstream side. In this regard, each of the first and second support devices establishes a non-rolling, line-type interface with the glass ribbon. In some embodiments, a “line-type interface” is in reference to the glass ribbon being fully supported across its width by a device that has an effective contact surface as small as possible. A glass ribbon can be assimilated to a planar surface, so for example a cylindrical shaped support device would be considered as creating a line-type interface or contact with the glass ribbon. The first support device is spaced from the second support device along the travel path. In some embodiments, between at least one of the first and second support devices, the line-type interface comprises a sliding interface. In other embodiments, between at least one of the first and second support devices, the line-type interface comprises a gas bearing interface. In some embodiments, the first support device is spaced from the second support device along the travel path by a distance of not less than 50 mm, with the glass ribbon not being directly supported by the conveying apparatus between the first and second support devices. 
     Yet other embodiments of the present disclosure relate to a system for processing a glass ribbon. The system comprises a conveying apparatus configured to establish a travel path for the glass ribbon from an upstream side to a downstream side. The conveying apparatus comprises a pulling device, a first support device, and a second support device. The pulling device is configured to apply a pulling force onto the glass ribbon, and is located proximate the downstream side. The first support device is upstream of the pulling device relative to the travel path. The second support device is between the first support device and the pulling device relative to the travel path. The first and second support devices are each configured to establish a no-rolling, line-type interface with the glass ribbon. Further, the first support device is spaced from the second support device along the travel path. In some embodiments, at least one of the first and second support devices comprises a contact surface having a low coefficient of friction with glass that is arranged to establish sliding contact with the glass ribbon. In some embodiments, “a low coefficient of friction with glass” relates to an ability of the body to support the glass ribbon without imparting visually discernable surface scratches at expected travel speeds. Some materials that are considered to have a low coefficient of friction with glass in accordance with principles of the present disclosure include, but are not limited to, graphite, boron nitride, and smooth silicon carbide (Ra&lt;1 micron). In some embodiments, at least one of the first and second support devices comprises a gas bearing support device. In some embodiments, the system further comprises a glass ribbon forming apparatus arranged to deliver a glass ribbon to the upstream side. 
     Additional features and advantages 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. 
     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 various embodiments described herein, and together with the description serve to explain the principles and operations of the claimed subject matter. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a simplified side view of a system processing a glass ribbon in accordance with principles of the present disclosure, the system including a conveying apparatus; 
         FIG. 2  is a simplified top view of a portion of the conveying apparatus of the system of  FIG. 1  processing a glass ribbon; 
         FIG. 3A  is a side view of a support device in accordance with principles of the present disclosure and useful with the conveying apparatus of  FIG. 1  processing a glass ribbon; 
         FIG. 3B  is a side view of a support device in accordance with principles of the present disclosure and useful with the conveying apparatus of  FIG. 1  processing a glass ribbon; 
         FIG. 3C  is a side view of a support device in accordance with principles of the present disclosure and useful with the conveying apparatus of  FIG. 1  processing a glass ribbon; 
         FIG. 4A  is a simplified cross-sectional view of a support device in accordance with principles of the present disclosure and useful with the conveying apparatus of  FIG. 1 ; 
         FIG. 4B  is a simplified end view of the support device of  FIG. 4A ; 
         FIG. 4C  is an enlarged view of a portion of the support device of  FIG. 4A  along the segment  4 C; 
         FIG. 5A  is a simplified cross-sectional view of the support device of  FIG. 4A  interfacing with a glass ribbon; and 
         FIG. 5B  is a simplified end view of the arrangement of  FIG. 5A . 
     
    
    
     DETAILED DESCRIPTION 
     Reference will now be made in detail to various embodiments of systems and methods for processing a glass ribbon, and in particular for removing warp from, or improving flatness in, a glass ribbon, for example a continuous glass ribbon. Whenever possible, the same reference numerals will be used throughout the drawings to refer to the same or like parts. 
     Some aspects of the present disclosure provide glass ribbon handling systems and methods in which a continuously conveyed or traveling glass ribbon is subjected to a cooling environment and is supported in such a way that desired flatness is minimally affected, if at all. With this in mind, one embodiment of a system  20  in accordance with principles of the present disclosure and useful in forming and processing a glass ribbon  22  is schematically shown in  FIG. 1 . Although the system  20  is described herein as being used to process a glass ribbon, it should be understood that the systems and methods of the present disclosure can also be used to process other types of materials such as polymers (e.g., Plexi-Glass™), metals, or other substrate materials. 
     The system  20  includes a glass ribbon supply apparatus  30  and a conveying apparatus  32 . As described in greater detail below, the glass ribbon supply apparatus  30  can assume a wide variety of forms appropriate for generating and delivering the glass ribbon  22  to an upstream side  40  (referenced generally) of the conveying apparatus  32 . The conveying apparatus  32  causes the glass ribbon  22  to travel from the upstream side  40  to a downstream side  42  (referenced generally). The glass ribbon  22  cools in an environment of the conveying apparatus  32  and thus experiences an increasing viscosity from the upstream side  40  to the downstream side  42 . 
     In some non-limiting embodiments, such as illustrated in  FIG. 1 , the glass ribbon supply apparatus  30  incorporates fusion processes in which molten glass  50  is routed to a forming body  52 . The forming body  52  comprises an open channel  54  positioned on an upper surface thereof, and a pair of converging forming surfaces  56  that converge at a bottom or root  58  of the forming body  52 . The molten glass  50  flows into the open channel  54  and overflows the walls thereof, thereby separating into two individual flow of molten glass that flow over the converging forming surfaces  56 . When the separate flow of molten glass reach the root  58 , they recombine, or fuse, to form a single ribbon of viscous molten glass (i.e., the glass ribbon  22 ) that descends from the root  58 . Various rollers  60  contact the viscous glass ribbon  22  along the edges of the ribbon and aid in drawing the ribbon  22  in a first, downward direction  62  (such as a vertical direction). The present disclosure is equally applicable to other variations of down draw glass making processes such as a single sided overflow process or a slot draw process, which basic processes are well known to those skilled in the art. 
     In some embodiments, the glass ribbon supply apparatus  30  can further include a redirecting device  64  that redirects the glass ribbon  22  from the first direction  62  into a second direction  66  for delivery to the conveying apparatus  32 . The redirecting device  64  is represented in  FIG. 1  by rollers  68 . In some embodiments, the glass ribbon  22  is turned by the redirecting device  64  through an angle of about 90 degrees and the second direction  66  is substantially horizontal (i.e., within 5 degrees of a truly horizontal orientation relative to the earth). In some embodiments, the redirecting device  64  does not physically contact the glass ribbon  22  (e.g., air bearings), or, in the event that contact is necessary, such as when rollers are used, contact can be limited to the edge portions of the glass ribbon  22 . 
     Other glass ribbon formation techniques are also acceptable that may or may not include the 90 degree turn described above, may or may not incorporate fusion processes, etc. Regardless, the molten, viscous glass ribbon  22  is continuously supplied to the upstream side  40  of the conveying apparatus  32 . 
     The conveying apparatus  32  includes a pulling device  70  and two or more discrete, spaced-apart support devices  72 . In general terms, the pulling device  70  is located at or immediately proximate the downstream side  42 , and exerts a pulling force onto the glass ribbon  22  to continuously convey the glass ribbon  22  along a travel path T defined, at least in part, by the support devices  72  as described below. While five of the support devices  72  are shown, any other number, either greater or lesser (including two) is equally acceptable. Thus, the conveying apparatus  32  includes at least an upstream-most support device  72   a  and a downstream-most support device  72   b.  In some non-limiting embodiments, the conveying apparatus  32  is configured for installation to the floor of a glass production facility, and thus can include framework (not shown) supporting one or more of the pulling device  70 , the support devices  72 , and other optional components such as rollers (or other transport devices) adjacent the pulling device  70  as are known in the art. 
     The pulling device  70  can assume a variety of forms appropriate for driving or pulling the glass ribbon  22 , and in some embodiments can be or can include a conventional nip roll device comprising first and second rollers  90 ,  92 . One or both of the rollers  90 ,  92  can be a driven roller as is known in the art. With these and similar configurations, the pulling device  70  can further include a controller (not shown), for example a computer-like device, programmable logic controller, etc., programmed to control a speed or travel rate of the glass ribbon  22  along the conveying apparatus  32 . Other pulling device configurations are also acceptable. 
     The support devices  72  can assume various forms as described below and can be located at various positions between the upstream side  40  and the downstream side  42  for interfacing with and supporting the glass ribbon  22  along the travel path T. In general terms, a configuration and a location of each of the support devices  72  are selected to support the traveling glass ribbon  22  with a non-rolling (e.g., sliding), line-type interface as a function, in some non-limiting embodiments, of an expected viscosity and/or temperature of the glass ribbon  22  at the point of interface with each particular one of the support devices  72  (it being recalled that in some embodiments, a temperature of the glass ribbon  22  decreases, and a viscosity of the glass ribbon  22  increases, from the upstream side  40  to the downstream side  42 ). In some embodiments, a “line-type interface” is in reference to the glass ribbon  22  being fully supported across its width by the support device  72  that otherwise has an effective interface or contact surface as small as possible. The glass ribbon  22  can be assimilated to a planar surface, so for example a cylindrical shaped support device  72  would be considered as creating a line-type interface or contact with the glass ribbon  22 . 
     One or more of the support devices  72  is or includes a stationary, low friction body establishing a sliding interface with the traveling glass ribbon  22 . Alternatively or in addition, one or more of the support devices  72  is or includes a gas bearing device operable to direct gas at the glass ribbon  22 , thus generating or forming a gas film or layer that supports the traveling glass ribbon  22 . With either construction, a non-rotating support zone or region  100  is established by each of the support devices  72  and at which the glass ribbon  22  is directly supported. In the simplified illustration of  FIG. 1 , the support zone  100  of each of the support devices  72  is drawn with a dashed line to reflect that the support zone  100  can be a material body (e.g., as with embodiments in which the support device  72  is or includes a low friction body that is in direct, physical contact with the glass ribbon  22 ) or can be a gas film (e.g., as with embodiments in the support device  72  is or includes a gas bearing device and with which the gas film exists upon operation of the gas bearing device). The travel path T as collectively established by the support devices  72  (as the glass ribbon  22  is being pulled by the pulling device  70 ) is thus relative to the corresponding support zones  100 , it being understood that where a particular one of the support devices  72  is a gas bearing device, the corresponding support zone  100  does not physically exist unless the support device  72  is operated to direct a flow of gas at the glass ribbon  22 . 
     The discrete, spaced-apart arrangement of the support devices  72  is in reference to the conveying apparatus  32  not directly supporting the glass ribbon  22  between successive support devices  72 . For example, with respect to the non-limiting example of  FIG. 1 , the glass ribbon  22  is not directly, physically supported by the conveying apparatus  32  between the support zone  100  of the upstream-most support device  72   a  and the support zone  100  of a first intermediate support device  72   c  that otherwise successively follows the upstream-most support device  72   a  along the travel path T. Alternatively stated, the support devices  72  each exert a normal force onto the glass ribbon  22  that supports the weight of the glass ribbon  22 ; between successive support devices  72 , the conveying apparatus  32  does not exert a normal force onto the glass ribbon  22  and thus the glass ribbon  22  is not directly supported by the conveying apparatus  32  between successive support devices  72 . The spaced-apart arrangement promotes a line-type interface with the glass ribbon  22  at each of the support zones  100  as described in greater detail below. With this in mind, the travel path T of the glass ribbon  22  along the conveying apparatus  32  is schematically shown in  FIG. 1  as being linear or planar (e.g., the glass ribbon  22  is linear or planar between the upstream-most support device  72   a  and the pulling device  70 ), including at locations between the support zones  100  of successive discrete, spaced-apart support devices  72 . It will be understood that  FIG. 1  reflects an instant in time of the otherwise traveling glass ribbon  22 . Due to the discrete, spaced-apart configuration and arrangement of the support devices  72  as well as the horizontal orientation of the glass ribbon  22 , absent a pulling force being applied by the pulling device  70  (i.e., were the glass ribbon  22  to be stationary or not moving) and under circumstances where the glass ribbon  22  has a relatively low viscosity, a catenary would likely form in the glass ribbon  22  (i.e., the glass ribbon  22  would likely sag or stretch) between successive support devices  72  under the force of gravity. Under normal operating conditions, the pulling force applied by the pulling device  70  creates tension in the glass ribbon  22  that in turn lessens the effects of gravity on the glass ribbon  22  between successive support devices  72 . 
     While in theory occurrences of catenaries could be eliminated, with the methods, systems and apparatuses of the present disclosure, a slight catenary may be formed in the glass ribbon  22  between successive ones of the support devices  72  under normal (and expected) operating conditions and is acceptable. The amplitude or level of a catenary between two successive support devices  72  is a function of the viscosity of the glass ribbon  22 , the pulling force, and the spacing between the successive support devices  72 . In some embodiments, based upon expected glass ribbon viscosity and pulling force parameters, a spacing between successive ones of the support devices  72  is selected to limit the catenary amplitude to less than 20 mm. For example, in some embodiments, a spacing between successive support devices  72  (and in particular between the respective support zones  100  of successive support device  72 ) is in the range of 100-500 mm, although other spacing parameters are envisioned. This optional spacing range can be appropriate, for example, where an expected viscosity of the glass ribbon  22  at the upstream side  40  is less than 10 8  Poise and the pulling device  70  is operated to move the glass ribbon  22  at a velocity in the range of 1-20 meters/minute (m/min), optionally at a velocity of 10-15 m/min Moreover, with embodiments in which the conveying apparatus  32  provides three or more of the support devices  72 , a spacing between consecutive support devices  72  need not be uniform. For example, where the expected viscosity of the glass ribbon  22  increases toward the downstream side  42 , a spacing between the support zones  100  of successive support devices  72  can increase in the downstream direction (e.g., a spacing between the support zones  100  of successive support devices  72  near the downstream side  42  can be greater than a spacing between successive support devices  72  near the upstream side  40 ). Regardless, in some embodiments a spacing along the travel path T between the support zones  100  of successive support devices  72  is not less than 50 mm, optionally not less than 100 mm, to better promote a line-type interface with the glass ribbon  22 . 
     As a point of reference,  FIG. 1  identifies a direction of travel D of the glass ribbon  22  as dictated by operation of the pulling device  70 . The simplified top view of  FIG. 2  identifies this same direction of travel D, along with several of the support devices  72 . The glass ribbon  22  has a cross-web dimension  110  that is perpendicular to the direction of travel D, defined as a distance between opposing side edges  112 ,  114 . The support devices  72  are each configured such that the corresponding support zone  100  has a major dimension  116  that is greater than the expected cross-web dimension  110 , and are each arranged such that the corresponding support zone  100  extends beyond the side edges  112 ,  114 . As previously described, the glass ribbon  22  is directly supported by the conveying apparatus  32  at each of the support zones  100 , and is free of direct support by the conveying apparatus  32  between the support zones  100  of successive support devices  72 . Depending upon a size, viscosity, and rate of travel of the glass ribbon  22 , as well as a configuration of each particular support device  72 , the glass ribbon  22  may not directly interface with an entirety of an available area of the corresponding support zone  100 . As such,  FIG. 2  represents an interface region  120  for each of the support devices  72  and at which the glass ribbon  22  is directly supported by the corresponding support zone  100 . In the representation of  FIG. 2 , a shape of the interface region  120  can be viewed as having a length  122  and a width  124 , and mimics a shape of the corresponding support zone  100 . In some embodiments, the width  124  can be substantially uniform (i.e., within 5% of a truly uniform width) across the length  122 . Regardless, the line-type interface can include the length  122  of one or more or all of the interface regions  120  being at least 10 times greater than the corresponding width  124 , alternatively at least 20 times greater. In some non-limiting embodiments, the line-type interface can include one or more or all of the support devices  72  being configured such that the width  124  of the resultant interface region  120  is less than 20 mm. The elongated shape of the interface region  120  generated by one or more or all of the support devices  72  can also be viewed as defining a centerline  126  (e.g., where the interface region  120  has the substantially uniform width  124 , the corresponding centerline  126  will be substantially parallel (i.e., within 5 degrees of a truly parallel arrangement) with the length  122 ). In some embodiments, one or more or all of the support devices  72  are arranged such that the centerline  126  of the corresponding interface region  120  is substantially perpendicular (i.e., within 5 degrees of a truly perpendicular arrangement) to the direction of travel D. 
     Returning to  FIG. 1  and with the above-described features in mind, in some embodiments one or more of the support devices  72  provided with the conveying apparatus  32  is or includes a material having a low coefficient of friction with glass and arranged to establish sliding contact with the glass ribbon  22  along the travel path T. For example  FIG. 3A  illustrates a sliding contact support device  150  useful as, or as part of, one or more of the support devices  72  ( FIG. 1 ) of the present disclosure. The support device  150  includes a body  152  forming or carrying a contact surface  154 . The contact surface  154  serves as the support zone  100  ( FIG. 1 ) as previously described, and is formed of a material having a low coefficient of friction with glass. In some embodiments, “a low coefficient of friction with glass” relates to an ability of the body  152  to support the glass ribbon  22  at the contact surface  154  without imparting visually discernable surface scratches at expected travel speeds. Some materials that are considered to have a low coefficient of friction with glass in accordance with principles of the present disclosure include, but are not limited to, graphite, boron nitride, smooth silicon carbide (Ra&lt;1 micron), and the like. In some embodiments, the contact surface  154  is integrally formed by the body  152  (i.e., the body  152  is formed of the selected low friction coefficient material). In other embodiments, the body  152  and the contact surface  154  are formed of differing materials, with the selected low friction coefficient material being applied to the body  152  to create the contact surface  154 . For example, graphite is a material having a very low fiction behavior on glass, and is relatively inexpensive and easy to machine. In some embodiments and with additional reference to  FIG. 1 , the contact surface  154  can be a graphite material (and/or the body  152  can be a graphite material body) where, for example, the expected temperature of the glass ribbon  22  along the travel path T at the region of interface with the contact surface  154  is less than about 450 degrees Celsius (° C.). In some embodiments, the contact surface  154  can be a sintered alpha silicon carbide material (and/or the body  152  can be a sintered alpha silicon carbide material body) where, for example, the expected viscosity of the glass ribbon  22  along the travel path T at the region of interface with the contact surface  154  is in the range of 5×10 6 -5×10 7  Poise. 
     Regardless of the exact material employed, the body  152  can have the right cylinder shape reflected by  FIG. 3A  such that at least a portion of the contact surface  154  is curved (e.g., the contact surface  154  can define or incorporate a convex curvature relative to the glass ribbon  22 ). Other shapes are also acceptable. For example, another embodiment sliding contact support device  160  useful as, or as part of, one or more of the support devices  72  ( FIG. 1 ) of the present disclosure is shown in  FIG. 3B . The support device  160  includes a body  162  forming or carrying a contact surface  164 . The contact surface  164  serves as the support zone  100  ( FIG. 1 ) as previously described, and is formed of a material having a low coefficient of friction with glass as described above. The contact surface  164  can be integrally formed by the body  162  (i.e., the body  162  is formed of the selected low friction coefficient material), or can be applied to the body  162  (i.e., the body  162  and the contact surface  164  are formed of differing materials, with the selected low friction coefficient material being applied to the body  162  to create the contact surface  164 ). Regardless, a transverse shape of the body  162  can be a square with rounded corners as shown such that at least a portion of the contact surface  164  is curved. 
     Another embodiment sliding contact support device  170  useful as, or as part of, one or more of the support devices  72  ( FIG. 1 ) of the present disclosure is shown in  FIG. 3C . The support device  170  and includes a body  172  forming or carrying a contact surface  174 . The contact surface  174  serves as the support zone  100  ( FIG. 1 ) as previously described, and is formed of a low friction coefficient material as described above. The contact surface  174  can be integrally formed by the body  172  (i.e., the body  172  is formed of the selected low friction coefficient material), or can be applied to the body  172  (i.e., the body  172  and the contact surface  174  are formed of differing materials, with the selected low friction coefficient material being applied to the body  172  to create the contact surface  174 ). Regardless, the body  172  can have a complex transverse shape such that at least a portion of the contact surface  174  is curved. More particularly, the contact surface  174  has a first side  176  opposite a second side  178 . The support device  170  is arranged such that when moving in the direction of travel D, the glass ribbon  22  contacts or interfaces with the first side  176  followed by the second side  178 . While the first and second sides  176 ,  178  of the contact surface  174  can both be curved, a radius of curvature of the first side  176  is less than (or “tighter”) than that of the second side  178  to minimize the potential contact area. In related embodiments, one or both of the sides  176 ,  178  can define a 90 degree corner. 
     Regardless of an exact shape, the body associated with the sliding contact support devices of the present disclosure (e.g., the support devices  150  ( FIG. 3A ),  160  ( FIG. 3B ),  170  ( FIG. 3C )) can be configured to provide the corresponding contact surface appropriate for line-type interface with the glass ribbon  22 . For example, a width of the contact surface associate with some embodiment sliding contact support devices of the present disclosure can optionally be in the range of 2-25 mm. 
     Returning to  FIG. 1 , in other embodiments, one or more of the support device  72  provided with the conveying apparatus  32  is or includes a gas bearing support device. As a point of reference air bearings have previously been considered in the in the transport of thick glass ribbons. With conventional air bearings used with thick glass ribbon handling, there is an intrinsic limitation at the edges of the glass ribbon where the air bearing effect diminishes or even vanishes. To address this problem, a specific design correction is required that either operates to maintain the glass ribbon at a high flying height via high air flow (as with a bearing head having discrete, machined orifices), or at a low flying height via high pressure (as with a porous material bearing head). In both cases, the thermal effect on the glass ribbon can be significant and may not be compatible with a desired cooling rate. In addition, the conventional air bearing design does not preclude the glass ribbon from contacting the head due to, for example, process variations or sequence. Conventional air bearing designs can be even more problematic in the transport of thin glass ribbons. Local cooling by direct contact with the bearing head can be particularly easy given the small thermal mass of the thin glass ribbon as compared to the large heat transfer generated by this heat transfer mode. The coupling between deformation and heat transfer through the exponential dependency of viscosity with temperature can create an oscillating condition that materializes in a wavy ribbon edge. A possible mechanism is that as a contact first occurs, the sudden viscosity increase makes it more difficult for the glass ribbon that follows to touch the cold head; as a result, non-uniform cooling can happen over time, leading to a substantive deformation in the glass ribbon. 
     Some embodiments of the present disclosure provide a gas bearing support device that addresses one or more of the above concerns. For example,  FIGS. 4A and 4B  illustrate a gas bearing support device  200  useful as, or as part of, one or more of the support devices  72  ( FIG. 1 ) of the present disclosure. The gas bearing support device  200  includes a gas bearing head  202  defining a distribution face  204  and forming at least one supply channel  206 . A plurality of orifices  208  (referenced generally in  FIG. 4A ) are formed through a thickness of the head  202 , and are open to the distribution face  204  and the supply channel  206 . With this construction, pressurized gas supplied to an inlet  210  of the supply channel  206  is distributed as a gas film from the distribution face  204  at levels (e.g., flow rate, pressure, etc.) sufficient to support the glass ribbon  22  ( FIG. 1 ) with a line-type interface. 
     The orifices  208  can be formed or defined in various manners. In some embodiments, the orifices  208  are machined into the head  202 . In other embodiments, construction of the head  202  can generate the orifices  208  (e.g., 3D printing). In yet other embodiments, the head  202 , or at least that portion of the head  202  defining the distribution face  204 , can comprise a porous material. The porous material can include graphite, ceramic, partially sintered metal, high temperature tolerant metal oxide(s), silicon carbide and other similar material which gas may be flowed at desired pressures (e.g., pressure in the range of 1×10 5 -3×10 5  pascal (Pa)). In some embodiments, and as best shown in the enlarged view of  FIG. 4C , the orifices  208  are in highly close proximity to one another (as a point of reference, gas flow through two of the orifices  208  is shown by arrows in  FIG. 4C ). For example, in some embodiments, a gap  212  between immediately adjacent ones of the orifices  208  is not greater than 5 mm, alternatively in the range of 1-5 mm, alternatively about 2.5 mm. Other dimensions are also envisioned. The orifices  208  are defined and arranged to generally maximize the points of distribution of gas from the distribution face  204  such that the effect of the resultant gas film is not local. In some embodiments, and as reflected by  FIG. 4B , the distribution face  204  can have a slightly convex shape to encourage formation of a slightly convex gas bearing or film for reasons made clear below. 
     Operation of the gas bearing support device  200  in supporting the glass ribbon  22  is shown in  FIGS. 5A and 5B . As a point of clarification, the direction of travel of the glass ribbon  22  in the view of  FIG. 5A  is into a plane of the page. Pressurized gas  220  (e.g., compressed air, compressed nitrogen, a mixture thereof, etc.) is supplied to the channel  206 . In some embodiments, the supplied gas  220  can be heated (e.g., to a temperature of at least 100° C.). Regardless, the orifices  208  ( FIG. 4C ) direct the gas  220  through the distribution face  204  and toward the glass ribbon  22 , forming a gas film  222  that interfaces with and supports the glass ribbon  22 . In some non-limiting embodiments, the distribution face  204  can be configured such that an effective shape of the resultant gas film  222  is slightly convex as reflected by  FIG. 5B . 
     Returning to  FIG. 1 , some methods of the present disclosure can include supplying the glass ribbon  22  to the inlet side  40  of the conveying apparatus  32  as a thin glass ribbon. For example, the glass ribbon  22  as supplied to the conveying apparatus  32  by the glass ribbon supply apparatus  30  can have a thickness of about 1 mm or less. In other embodiments, the glass ribbon  22  as supplied to the conveying apparatus  32  exhibits a thickness in the range from about 0.1 mm to about 5 mm, from about 0.1 mm to about 4 mm, from about 0.1 mm to about 3 mm, from about 0.1 mm to about 2 mm, from about 0.1 mm to about 1 mm, and all ranges and sub-ranges therebetween. In some related, non-limiting embodiments, the glass ribbon  22  can have a width from about 60 mm to about 100 mm. In some related, non-limiting embodiments, the glass ribbon  22  as supplied to the conveying apparatus  32  by the glass ribbon supply apparatus  30  has a viscosity of 10 8  Poise or less, and is at a temperature of at least 200° C. The glass ribbon  22  is threaded to the pulling device  70 , and the pulling device  70  is operated to apply a pulling force onto the glass ribbon  22 . The so-applied pulling force causes the glass ribbon  22  to travel through the conveying apparatus  32  along the travel path T as defined, in part, by the support devices  72 . In some embodiments, the glass ribbon  22  is caused to travel at a rate or velocity in the range of 1-20 m/min, alternatively 10-15 m/min The glass ribbon  22  cools while traversing from the inlet side  40  to the outlet side  42 . While traveling along the travel path T, the glass ribbon  22  interfaces with the support devices  72 , with the support devices  72  each establishing a non-rolling, line-type interface with the glass ribbon  22 . In some embodiments, the glass ribbon  22  cools and experiences an increase in viscosity when traveling from the inlet side  40  to the outlet side  42 . 
     The glass ribbon processing systems, conveying apparatuses, and methods of the present disclosure can provide a marked improvement over previous designs and techniques. Some systems, apparatuses and methods of the present disclosure include non-rolling interface with a traveling glass ribbon. As compared to conventional glass ribbon conveyor constructions that otherwise employ rollers, the systems, apparatuses and methods of the present disclosure can minimize or remove friction thus minimizes or eliminating a source of surface scratches that can be considered cosmetic defects and/or create flaws that might reduce mechanical strength, and avoids angular and/or velocity mismatch thus removing a source of in-plane compressive stresses that can drive out-of-plane deformation. Further, the non-rolling, line-type glass ribbon interface provided by the systems, conveying apparatuses, and methods of the present disclosure can decrease the likelihood of the thermal scarring. 
     Various modifications and variations can be made the embodiments described herein without departing from the 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 modifications and variations come within the scope of the appended claims and their equivalents.