Inventors:
Ronald L. Schwenninger - Allison Park PA, US
Assignee:
PPG INDUSTRIES OHIO, INC. - Cleveland OH
International Classification:
C03B 5/225, C03C 3/00, G02B 1/11, C03B 3/00, C03B 18/02, C03C 3/087, C03B 5/16
US Classification:
359601, 501 70, 501 11, 651341, 65 83, 651345, 65 90, 65 992, 651344
Abstract:
A soda-lime-silica glass for solar collector cover plates and solar mirrors has less than 0.010 weight percent total iron as FeO, a redox ratio of less than 0.350, less than 0.0025 weight percent CeO, and spectral properties that include a visible transmission, and a total solar infrared transmittance, of greater than 90% at a thickness of 5.5 millimeters, and reduced solarization. In one non-limiting embodiment of invention, the glass is made by heating a pool of molten soda-lime-silica with a mixture of combustion air and fuel gas having an air firing ratio of greater than 11, or an oxygen firing ratio of greater than 2.31. In another non-limiting embodiment of the invention, streams of oxygen bubbles are moved through a pool of molten glass. In both embodiments, the oxygen oxidizes ferrous iron to ferric iron to reduce the redox ratio.