| 摘要 |
Methods for controlling the bow (shape) of a vertical glass ribbon (13) produced by a downdraw process are provided. The methods involve passing the ribbon (13) through a gas-filled vertical enclosure (23), e.g., a draw tower, whose bottom (31) is open to the atmosphere. The ribbon (13) acts as a septum that divides the enclosure's internal volume (29) into a first sub-volume (25) and a second sub-volume (27). Using the stack effect, a positive pressure difference is produced between the first sub-volume (25) and the second sub-volume (27) along at least a portion of the length of the enclosure (the DDZ). The edges of the ribbon (13) are constrained so that they do not move into the second sub-volume (27) over at least the DDZ. As a result, the ribbon bows with its concavity facing the first sub-volume (25) and its convexity facing the second sub-volume (27). |
