Electrically modified float glass manufacturing methods

Claim 1

IN A GLASS MANUFACTURING METHOD IN WHICH A METALLIC DISPERSION OF PREDETERMINED INTENSITY IS DEVELOPED IN A SURFACE OF THE GLASS WHOSE COMPOSITION INCLUDES ALKALI-METAL OXIDE, WHICH GLASS IS AT A TEMPERATURE AT WHICH THE GLASS IS SUSCEPTIBLE TO SURFACE MODIFICATION BY REDUCTION OF METAL IONS INTRODUCED INTO THE GLASS SURFACE IN A PREDETERMINED CONCENTRATION BY ELECTROLYTIC MIGRATION CAUSED BY AN ELECTRIC FLUX DENSITY ESTABLISHED FROM A FIRST MOLTEN METAL BODY WHICH IS ANODIC WITH RESPECT TO THE GLASS, THE IMPROVEMENT COMPRISING: AT A PRESET TIME AFTER COMPLETION OF SAID ELECTROLYTIC MIGRATION, AT WHICH TIME ARE SUFFICIENT ALKALI-METAL IONS IN THE GLASS SURFACE TO PROVIDE A SUBSEQUENT CATHODIC ELECTRIC FLUX DENSITY FROM THE GLASS SURFACE TO A SECOND MOLTEN METAL BODY, CONTACTING THAT GLASS SURFACE WITH SAID SECOND MOLTEN METAL BODY WHICH IS CATHODIC WITH RESPECT TO THE GLASS AND IS SUFFICIENTLY REDUCING WITH RESPECT TO SAID METAL IONS IN SAID GLASS SURFACE TO REDUCE SAID METAL IONS IN SAID ION-RICH SURFACE TO METALLIC FORM, AND ESTABLISHING, WHILE MAINTAINING THAT CONTACT, SAID CATHODIC ELECTRIC FLUX DENSITY FROM THE GLASS SURFACE TO SAID SECOND MOLTEN METAL BODY WHICH IS SUFFICIENT TO EFFECT SUCH REDUCTION TO METALLIC FORM OF SAID METAL IONS IN SAID ION-RICH SURFACE AS PRODUCES IN SAID GLASS SURFACE SAID METALLIC DISPERSION OF PREDETERMINED INTENSITY.

Claim 6

A method of manufacturing soda-lime-silica glass having a metallic dispersion of predetermined intensity developed in a surface thereof, comprising advancing the glass in ribbon form along a bath of molten metal, maintaining the glass at a temperature at which it susceptible to surface modification, contacting the glass at that temperature with a first molten metal body, connecting said first molten metal body as an anode with respect to the glass, establishing an anodic electric flux density from said first molten metal body into the glass surface to cause sufficient electrolytic migration of reducible metal ions into the glass surface to render said glass surface rich in said reducible metal ions, then after a preset time interval contacting the glass with a second molten metal body which is reducing with respect to the reducible metal ions in the glass, connecting said second molten metal body as a cathode with respect to the glass, establishing a cathodic electric flux density from the reducible metal ion-rich glass surface to that second molten metal body, setting said cathodic electric flux density to a value to promote cathodic reduction of sufficient of said reducible metal ions in the ion-rich glass surface to produce the required metallic dispersion in said glass surface in the time of maintenance of contact between said second molten metal body and the glass surface, and presetting the time interval of exposure of the advancing ion-rich glass surface between said first and second molten metal bodies to provide at the end of said exposure time a sodium ion concentration in the glass surface sufficient to provide said cathodic electric flux density and to avoid significant migration of said reducible metal ions from the glass into said second molten metal body.

Claim 7

A method of manufacturing soda-lime-silica glass having a metallic dispersion of predetermined intensity developed in a surface thereof, comprising advancing the glass in ribbon form along a bath of molten metal, maintaining the glass at a temperature at which it susceptible to surface modification, contacting the glass at that temperature with a first molten metal body, connecting said first molten metal body as an anode with respect to the glass, establishing an anodic electric flux density from said first molten metal body into the glass surface to cause sufficient electrolytic migration of reducible metal ions into the glass surface to render said glass surface rich in said reducible metal ions, then after a preset time interval contacting the glass with a second molten metal body which is reducing with respect to the reducible metal ions in the glass, connecting said second molten metal body as a cathode with respect to the glass, establishing a cathodic electric flux density from the reducible metal ion-rich glass surface to that second molten metal body, setting said cathodic electric flux density to a value to promote cathodic reduction of sufficient of said reducible metal ions in the ion-rich glass surface to produce the required metallic dispersion in said glass surface in the time of maintenance of contact between said second molten metal body and the glass surface, and presetting the time interval of exposure of the advancing ion-rich glass surface between said first and second molten metal bodies to provide at the end of said exposure time a sodium ion concentration in the glass surface sufficient to provide said cathodic electric flux density and to avoid significant migration of said reducible metal ions from the glass into said second molten metal body.

Claim 15

A method of manufacturing float glass of soda-lime-silica composition having a copper/lead dispersion in one surface thereof comprising: advancing the glass in ribbon form along a bath of molten metal while maintaining the glass at a temperature at which it is susceptible to surface modification; contacting the upper surface of the ribbon of glass at that temperature with a first molten body of copper/lead alloy; connecting said first molten copper/lead alloy body as an anode with respect to the glass and establishing an anodic electric flux density of from 310 to 620 coulombs per square meter from said first body into the upper surface of the ribbon to cause electrolytic migration of copper and lead ions into the glass surface; then after a time of from 1 to 4 seconds after the ribbon surface emerges from beneath said first molten alloy body, contacting the ribbon surface with a second molten copper/lead alloy body; connecting said second molten copper/lead alloy body as a cathode with respect to the glass and establishing a cathodic electric flux density of from 93 to 310 coulombs per square Meter from the upper surface of the ribbon into said second body which reduces sufficient copper and lead ions in the glass surface to provide from 68 to 116 mg/m2 of copper and from 100 to 600 mg/m2 of lead in a surface layer of the glass at most 0.1 microns thick.

Claim 16

A method of manufacturing float glass of soda-lime-silica composition having a copper/lead dispersion in one surface thereof comprising: advancing the glass in ribbon form along a bath of molten metal while maintaining the glass at a temperature at which it is susceptible to surface modification; contacting the upper surface of the ribbon of glass at that temperature with a first molten body of copper/lead alloy; connecting said first molten copper/lead alloy body as an anode with respect to the glass and establishing an anodic electric flux density of from 310 to 620 coulombs per square meter from said first body into the upper surface of the ribbon to cause electrolytic migration of copper and lead ions into the glass surface; then after a time of from 1 to 4 seconds after the ribbon surface emerges from beneath said first molten alloy body, contacting the ribbon surface with a second molten copper/lead alloy body; connecting said second molten copper/lead alloy body as a cathode with respect to the glass and establishing a cathodic electric flux density of from 93 to 310 coulombs per square Meter from the upper surface of the ribbon into said second body which reduces sufficient copper and lead ions in the glass surface to provide from 68 to 116 mg/m2 of copper and from 100 to 600 mg/m2 of lead in a surface layer of the glass at most 0.1 microns thick.

Claim 19

A method of manufacturing float glass of soda-lime-silica composition having a copper/bismuth dispersion in one surface thereof comprising: advancing the glass in ribbon form along a bath of molten metal over which an inert atmosphere is maintained while maintaining the glass at a temperature at which it is susceptible to surface modification; contacting the upper surface of the ribbon of glass at that temperature with a first molten body of copper/bismuth alloy; connecting said first molten copper/bismuth alloy body as an anode with respect to the glass and establishing an anodic electric flux density of 800 coulombs per square meter from said first body into the upper surface of the ribbon to cause electrolytic migration of copper and bismuth ions into the glass surface; then after a time of the order of 0.5 seconds after the ribbon surface emerges from beneath said first molten alloy body, contacting the ribbon surface with a second molten copper/bismuth alloy body; connecting said second molten copper/bismuth alloy body as a cathode with respect to the glass and establishing a cathodic electric flux density of 515 coulombs per square meter from the upper surface of the ribbon into said second body and sufficient to provide by reduction 515 mg/m2 of copper and 11 mg/m2 of lead in a surface layer of the glass at most 0.1 microns thick.

Claim 20

A method of manufacturing float glass of soda-lime-silica composition having a copper/bismuth dispersion in one surface thereof comprising: advancing the glass in ribbon form along a bath of molten metal over which an inert atmosphere is maintained while maintaining the glass at a temperature at which it is susceptible to surface modification; contacting the upper surface of the ribbon of glass at that temperature with a first molten body of copper/bismuth alloy; connecting said first molten copper/bismuth alloy body as an anode with respect to the glass and establishing an anodic electric flux density of 800 coulombs per square meter from said first body into the upper surface of the ribbon to cause electrolytic migration of copper and bismuth ions into the glass surface; then after a time of the order of 0.5 seconds after the ribbon surface emerges from beneath said first molten alloy body, contacting the ribbon surface with a second molten copper/bismuth alloy body; connecting said second molten copper/bismuth alloy body as a cathode with respect to the glass and establishing a cathodic electric flux density of 515 coulombs per square meter from the upper surface of the ribbon into said second body and sufficient to provide by reduction 515 mg/m2 of copper and 11 mg/m2 of lead in a surface layer of the glass at most 0.1 microns thick.