Methods and apparatuses for steering flexible glass webs

Abstract

Methods and apparatuses for steering flexible glass webs are disclosed. In one embodiment, a steering device for non-contact steering of a glass web having a conveyance direction and a cross direction normal to the conveyance direction includes a fluid injection bar having an elongate axis oriented in a cross direction of the glass web. The steering device also includes a pivot bearing assembly coupled to the fluid injection bar such that the fluid injection bar is pivotable in a plane perpendicular to the conveyance direction of the glass web, an actuator coupled to the fluid injection bar for adjusting the orientation of the fluid injection bar with respect to the glass web, and an edge detection device positioned proximate to an edge of the glass web for evaluating a position of an edge of the glass web.

What is claimed is: 
     
         1 . A method of steering a glass web comprising:
 directing the glass web along a glass manufacturing apparatus in a conveyance direction, the glass web having a cross direction normal to the conveyance direction;   conveying the glass web over a steering device, the steering device comprising a pivotable fluid injection bar and an edge detection device positioned proximate to an edge of the glass web, the pivotable fluid injection bar comprising:
 a steering surface positioned proximate to the glass web, the steering surface comprising: 
 an introduction zone; 
 an exit zone positioned downstream from the introduction zone relative to the conveyance direction; and 
 a plurality of openings that perforate the steering surface and allow injection of fluid between the steering surface and the glass web, wherein a density of the plurality of openings proximate the introduction zone and the exit zone is greater than a density of the plurality of openings at positions between the introduction zone and the exit zone, wherein the pivotable fluid injection bar emits the fluid from the plurality of openings such that the glass web is supported over and spaced apart from the steering surface; 
   sensing a lateral position of the edge of the glass web with the edge detection device positioned proximate to the edge of the glass web, the edge detection device providing a position signal indicative of a position of a first edge of the glass web;   calculating automatically with at least one processor the lateral position of the glass web based on the position signal received from the edge detection device; and   pivoting the pivotable fluid injection bar of the steering device to shift the glass web in an inward direction when the edge detection device senses that the edge of the glass web is positioned outwardly offset from a pre-determined set point, or   pivoting the pivotable fluid injection bar of the steering device to shift the glass web in an outward direction when the edge detection device senses that the edge of the glass web is positioned inwardly offset from the pre-determined set point.   
     
     
         2 . The method of  claim 1 , wherein:
 the glass web defines a first edge path length and a second edge path length as the glass web is directed along the glass manufacturing apparatus in the conveyance direction; and   pivoting the pivotable fluid injection bar with respect to the glass manufacturing apparatus such that the first edge path length is the same as the second edge path length.   
     
     
         3 . The method of  claim 1 , wherein the steering device further comprises a pivot bearing assembly coupled to the pivotable fluid injection bar such that the pivotable fluid injection bar is pivotable in a plane perpendicular to the conveyance direction of the glass web and an actuator coupled to the pivotable fluid injection bar for adjusting an orientation of the pivotable fluid injection bar with respect to the glass web. 
     
     
         4 . The method of  claim 1 , further comprising conveying the glass web over a planar fluid injection bar, wherein the planar fluid injection bar injects a fluid between the glass web and the planar fluid injection bar to maintain a fly height of the glass web at a position that is at least one of upstream and downstream of the steering device relative to the conveyance direction. 
     
     
         5 . The method of  claim 1 , further comprising conveying the glass web over a static reverser, wherein the static reverser comprises a fixed fluid injection bar that injects a fluid between the glass web and the static reverser, wherein the fixed fluid injection bar is maintained in a fixed position relative to the glass web. 
     
     
         6 . The method of  claim 1 , further comprising coiling the glass web onto a take-in roll downstream of the steering device relative to the conveyance direction. 
     
     
         7 . The method of  claim 1 , wherein directing the glass web along the glass manufacturing apparatus in the conveyance direction comprises uncoiling the glass web from a pay out roll. 
     
     
         8 . A method for producing a glass web comprising:
 melting glass batch materials to form molten glass;   forming the molten glass into the glass web;   conveying the glass web over a steering device, the steering device comprising a pivotable fluid injection bar and an edge detection device positioned proximate to an edge of the glass web, the pivotable fluid injection bar comprising:
 a steering surface positioned proximate to the glass web, the steering surface comprising: 
 an introduction zone; 
 an exit zone positioned downstream from the introduction zone relative to a conveyance direction; and 
 a plurality of openings that perforate the steering surface and allow injection of fluid between the steering surface and the glass web, wherein a density of the plurality of openings proximate the introduction zone and the exit zone is greater than a density of the plurality of openings at positions between the introduction zone and the exit zone, wherein the pivotable fluid injection bar emits the fluid from the plurality of openings such that the glass web is supported over and spaced apart from the steering surface; 
   sensing a lateral position of the edge of the glass web with the edge detection device and providing a position signal indicative of a position of a first edge of the glass web;   calculating automatically with at least one processor the lateral position of the glass web based on the position signal from the edge detection device;   pivoting the pivotable fluid injection bar of the steering device to shift the glass web in an inward direction when the edge detection device senses that the edge of the glass web is positioned outwardly offset from a pre-determined set point; or   pivoting the pivotable fluid injection bar of the steering device to shift the glass web in an outward direction when the edge detection device senses that the edge of the glass web is positioned inwardly offset from the pre-determined set point; and   conveying the glass web into a cutting device.   
     
     
         9 . The method of  claim 8 , wherein forming the glass web comprises flowing the molten glass over two sides of a forming vessel, wherein the molten glass flowing over the two sides of the forming vessel fuse at a root thereof to form the glass web. 
     
     
         10 . The method of  claim 8 , further comprising separating edge beads from the glass web with the cutting device. 
     
     
         11 . The method of  claim 10 , wherein the cutting device is a laser cutting device. 
     
     
         12 . The method of  claim 9 , wherein the steering device further comprises a pivot bearing assembly coupled to the pivotable fluid injection bar such that the pivotable fluid injection bar is pivotable in a plane perpendicular to the conveyance direction of the glass web and an actuator coupled to the pivotable fluid injection bar for adjusting an orientation of the pivotable fluid injection bar with respect to the glass web.