Transparent infrared absorbing glass and method of making
AssigneePPG Industries Ohio, Inc.
InventorsGeorge A. Pecoraro, Larry J. Shelestak
Life of this patent
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Abstract
A glass product having high visible transmittance, low infrared transmittance, and, optionally, reduced ultraviolet transmittance is produced in a manner compatible with continuous, commercial manufacture of flat glass by employing a moderate amount of iron in the glass composition and controlling reducing conditions to maintain a relatively large portion of the iron in the ferrous state.
Claims34
A method of manufacturing soda-lime-silica flat glass in a continuous process including feeding raw materials to a melting operation that includes separate liquefying and refining stages, passing from the melting operation to a flat glass forming operation a continuous stream of molten glass having at least 0.45 percent by weight iron expressed as Fe2O3, forming the glass into a flat glass product in the forming operation, melting the raw materials in a thin layer in the liquefying stage while controlling oxidation-reduction conditions in that stage and in subsequent stages so as to yield a glass having at least 35 percent of the iron in the ferrous state expressed as FeO and which when formed into a flat glass product of suitable thickness exhibits the combination of luminous transmittance of at least 65 percent and infrared transmittance of no more than 15 percent.
A soda-lime-silica glass article having a composition consisting essentially of, on a weight basis:
- 66 to 75% SiO2, 12-20% Na2O, 7-12% CaO, 0-5% MgO, 0-4% Al2O3, 0-3% K2O, 0.45-1% Fe2O3, 0-1.5% total of CeO2, TiO2, V2O5 or MoO3, at least 50 percent of the iron being in the ferrous state expressed as FeO, less than 0.02 percent by weight sulfur expressed as SO3, and exhibiting luminous transmittance of at least 65 percent and total solar infrared transmittance of no more than 15 percent at a selected thickness.
A soda-lime-silica glass article having a composition consisting essentially of, on a weight basis:
- 66-75% SiO2, 12-20% Na2O, 7-12% CaO, 0-5% MgO, 0-4% Al2O3, 0-3% K2O, 0-1.5% total of CeO2, TiO2, V2O5, or MoO3, optionally residual amounts of refining aids, and less than about 0.55% total iron oxide expressed as Fe2O3, at least 50 percent of the iron being in the ferrous state expressed as FeO, the iron being present in sufficient quantities to limit total solar infrared transmittance to no more than 15 percent while luminous transmittance is at least 65 percent at a selected thickness.
A soda-lime-silica glass article having a composition consisting essentially of, on a weight basis:
- 66-75% SiO2, 12-20% Na2O, 7-12% CaO, 0-5% MgO, 0-4% Al2O3, 0-3% K2O, 0-1.5% total CeO2, TiO2, V2O5, or MoO3 and less than about 0.55% total iron expressed as Fe2O3, at least 50 percent of the iron being in the ferrous state expressed as FeO, the iron being present in sufficient quantities to limit total solar infrared transmittance to no more than 15 percent while the luminous transmittance is at least 65 percent at a selected thickness.
Dependencies are inferred from the claim text.