Method of and apparatus for controlling erosion of a refractory threshold
AssigneePPG Industries, Inc.
InventorGeorge A. Pecoraro
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Abstract
A method of controlling the erosion of a refractory threshold over which molten glass flows transverse to the longitudinal centerline thereof, which includes preferentially cooling the central portion of the threshold while maintaining the marginal edge portions at a temperature above the liquidus temperature of the molten glass. A cooling fluid conduit extending longitudinally through the refractory threshold is thermally insulated adjacent its end portions, thereby localizing the cooling effect towards the central portion of the threshold.
Claims9
In a glassmaking process in which a stream of molten glass flows longitudinally from a melting furnace into a forming chamber over a transversely extending refractory threshold, wherein the flow of molten glass on the threshold causes the threshold to erode more rapidly at center portions than at marginal edge portions, the improvement comprising:
- cooling center portions of the threshold at a greater rate than marginal edge portions of the threshold are cooled so that the temperature of the center portions of the threshold is reduced relative to the temperature of the marginal edge portions to a sufficient extent to render erosion of the threshold more uniform over its entire glass contact surface.
A structure for delivering a stream of molten glass from a melting furnace onto a pool of molten metal in a forming chamber, comprising a refractory threshold extending transversely across the path of glass flow and positioned to contact and support the molten glass stream immediately before it contacts the molten metal, cooling means in heat exchange relationship with the threshold for retarding erosion of the threshold, the heat exchange relationship having variations in the transverse direction so as to provide a greater cooling rate in center portions of the threshold than in end portions, whereby erosion of the threshold is made more uniform.
Dependencies are inferred from the claim text.