Process and apparatus for surface modification of glass

Claim 2

A method according to claim 1, characterized by continuously introducing said element into the body of molten electrically conductive material, and controlling the introduction of said element in relation to the rate of advance of the glass and the strength of the electric current so as to maintain a desired concentration of said element in the body of molten material.

Claim 3

A method according to claim 1, wherein the molten electrically conductive material is a molten metal or a molten alloy.

Claim 4

A method according to claim 1, wherein the body of molten material clings to a metal-locating member through which electrical connection is made to the molten material.

Claim 5

A method according to claim 5, wherein the metal of the locating member is a member of the group consisting of osmium, palladium, platinum, rhodium, ruthenium, iridium and rhenium.

Claim 6

A method according to claim 4, wherein the molten alloy comprises at least two metals which are to enter the glass, and the temperature of the alloy and the electric current are selectively regulated to cause migration of said two metals into the glass in a proportion to produce desired characteristics in the glass.

Claim 7

A method according to claim 7, wherein the molten body is a molten alloy and the locating member comprises one of the metals of the alloy, which metal migrates into the glass.

Claim 8

A method according to claim 1, comprising continuously forming a ribbon of glass and advancing the ribbon at a controlled rate, maintaining two bodies of molten electrically conductive material against the glass surface by causing the molten bodies to cling to locating members adjacent the glass, and passing a controlled electric current through the glass between said bodies thereby modifying the constitution of the glass.

Claim 9

A method according to claim 9, wherein the bodies of molten electrically conductive material are held against opposite faces of the ribbon so that the electric current flows through the thickness of the glass.

Claim 10

A method according to claim 1, of producing a glass article having predetermined characteristics other than the natural characteristics inherent in the method of forming the article, characterized in that when the article is sufficiently hot to be electrically conductive, a body of a molten electrically conductive material clinging to a locating member is held against one face of the article, said body containing an element capable of producing the desired characteristic when incorporated in the article, an electric current is passed through the article between said body and an electrically conductive body contacting the other face of the article to cause migration of said element into the article, and said electric current is regulated whereby the concentration of said element incorporated in the article is adjusted to produce the desired characteristic.

Claim 11

Apparatus for use in the production of float glass, comprising a tank structure containing a bath of molten metal, a roof structure defining a headspace over the bath, means for maintaining a plenum of protective atmosphere in the headspace, means for delivering glass at a controlled rate to the bath and for advancing the glass along the bath as a layer of molten glass in ribbon form, an elongated, bar-shaped metal electrode mounted across the tank structure transversely and just above the path of travel of the glass so as to be adjacent one face of the glass, means for maintaining a body of molten electrically conductive material clinging by surface tension forces to said electrode and suspended therefrom against said one face of the glass, an electrical connection to the bath of molten metal, and a regulatable current supply circuit connected to the metal electrode and, through said electrical connection, to the molten metal bath, to engender current flow between the body of molten material and the glass.

Claim 12

Apparatus according to claim 12, wherein the bar-shaped electrode is made from a metal which is a member of the group consisting of platinum, palladium, ruthenium, rhodium, osmium, iridium and rhenium.

Claim 13

Apparatus according to claim 12, wherein the bar-shaped electrode is made from a metal which is a member of the group consisting of silicon, titanium, manganese, chromium, iron, vanadium, cobalt, nickel, copper, silver and gold.

Claim 14

Apparatus according to claim 12, wherein the electrode is formed with an aperture extending downwardly through the electrode, a bar of a metal to be introduced into the glass is fitted into the aperture and is connected to means for gradually lowering the bar through the aperture so that it maintains the concentration of that metal in the body of molten electrically conductive material clinging to the electrode.

Claim 15

Apparatus for use in the production of float glass, comprising a tank structure containing a bath of moLten metal, a roof structure defining a headspace over the bath, means for maintaining a plenum of protective atmosphere in the headspace, means for delivering glass at a controlled rate to the bath and for advancing the glass along the bath as a layer of molten glass in ribbon form, a strip of metal foil anchored at its ends to opposite sides of the tank structure so that the foil is held transversely and just above the path of travel of the glass and is adjacent one face of the glass, means for maintaining a body of molten electrically conductive material clinging by surface tension forces to said foil and suspended therefrom against said one face of the glass; an electrical connection to the bath of molten metal, and a regulatable current supply circuit connected to said foil and, through said electrical connection, to the molten metal bath, to engender current flow between the body of molten material and the glass.

Claim 16

Apparatus for use in the production of float glass, comprising a support for the glass constituted by a bath of molten metal, heaters associated with the bath for controlling the electrical conductivity of the glass, an elongated receptacle of porous refractory material mounted transversely of and just above the path of travel of the glass along the bath so as to be adjacent one face of the glass, means for maintaining a quantity of molten salt in said receptacle, which molten salt percolates through the receptacle to replenish a body of molten salt clinging to the bottom of the container and suspended therefrom against said one face of the glass, an electrical connection to said bath, an electrical connection to said body of molten salt, and a regulatable current supply circuit connected to said electrical connections to engender current flow between said body of molten salt and the glass.