Method of manufacturing heat absorbing glass

Claim 1

The method of claim 1 in which a reducing gas is bubbled through the glass melt.

Claim 5

The method of making a high infrared radiation absorbing, high visible light transmitting, sodA-lime-silica flat glass article useful for motor vehicle windshields and architectural applications, comprising: a. preparing a glass batch composition by adding to a batch of soda-lime-silica glass making ingredients, i. 0.05 to 2.0 percent by weight iron measured as Fe0; the iron being added in the form of metallic iron or compounds of ferrous or ferric ions to provide a ferrous-ferric equilibrium upon the melting of said glass batch composition, ii. 0.1 to 5 percent by weight tin measured as Sno; at least part of the tin being added in the form of compounds of stannous ions; b. melting the glass batch composition to form a glass melt so that an internal reduction occurs to shift the normally occurring ferrous-ferric ion equilibrium to the ferrous state; c. forming a flat glass article from said glass melt in which at least 80 percent of the total iron in the glass is in the ferrous state, and the mole ratio of stannous ions to ferrous ions is at least 1:1, the stannous ion serving as an internal reducing agent in the glass; and d. cooling said flat glass article.

Claim 10

The method of making a high infrared radiation absorbing, high visible light transmitting, soda-lime-silica flat glass article useful for motor vehicle windshields and architectural applications, comprising: a. preparing a glass batch composition by adding to a batch of soda-lime-silica glass making ingredients, i. 0.05 to 2.0 percent by weight iron measured as Fe0; the iron being added in the form of metallic iron or compounds of ferrous or ferric ions to provide a ferrous-ferric equilibrium upon the melting of said glass batch composition, ii. 0.1 to 5 percent by weight tin measured as Sn0; at least part of the tin being added in the form of compounds of stannic ions; b. melting the glass batch composition to form a glass melt; c. introducing a reducing agent into said glass melt to convert the stannic ions in said melt to stannous ions and to shift the normally occurring ferrous-ferric ion equilibrium to the ferrous state; d. forming a flat glass article from said glass melt in which at least 80 percent of the total iron in the glass is in the ferrous state, and the mole ratio of stannous ion to ferrous ion is at least 1:1, the stannous ions serving as an internal reducing agent in the glass; and e. cooling said flat glass article.