APPARATUS AND METHOD FOR CONTROLLING THICKNESS OF A FLOWING RIBBON OF MOLTEN GLASS

摘要

In the formation of sheet material from molten glass, a heat sink is positioned in the forming area for absorbing heat energy from discrete localized portions of the molten glass proximate a draw line or root to control local thickness variations in the sheet and thereby provide a uniform glass sheet thickness across the width of the sheet. The heat sink may be disposed in a fixture configured to rotate or pivot the heat sink (i.e. cooling member) about at least one axis, thereby absorbing heat from the flowing molten glass. The heat sink may also be inserted or withdrawn toward or away from the flowing molten glass to vary the amount of heat energy extracted by the cooling member (and thereby the viscosity and thickness of the local region cooled by the cooling member). The cooling is accomplished without directing a cooling gas from the cooling member toward the flowing molten glass.