A tempered glass has a compressive stress layer in a surface thereof, includes as a glass composition, in terms of mass %, 50 to 80% of SiO.sub.2, 10 to 30% of Al.sub.2O.sub.3, 0 to 6% of B.sub.2O.sub.3, 0 to 2% of Li.sub.2O, and 5 to 25% of Na.sub.2O, and is substantially free of As.sub.2O.sub.3, Sb.sub.2O.sub.3, PbO, and F.

A tempered glass has a compressive stress layer in a surface thereof, includes as a glass composition, in terms of mass %, 50 to 80% of SiO.sub.2, 10 to 30% of Al.sub.2O.sub.3, 0 to 6% of B.sub.2O.sub.3, 0 to 2% of Li.sub.2O, and 5 to 25% of Na.sub.2O, and is substantially free of As.sub.2O.sub.3, Sb.sub.2O.sub.3, PbO, and F.

Provided are an apparatus and a method for making a strengthened glass sheet including a glass layer with a first coefficient of thermal expansion and a first non-glass surface film formed on the glass layer, wherein the first non-glass surface film has a second coefficient of thermal expansion that is less than the first coefficient of thermal expansion and a compressive stress of at least 700 MPa.

Provided are an apparatus and a method for making a strengthened glass sheet including a glass layer with a first coefficient of thermal expansion and a first non-glass surface film formed on the glass layer, wherein the first non-glass surface film has a second coefficient of thermal expansion that is less than the first coefficient of thermal expansion and a compressive stress of at least 700 MPa.

A glass forming apparatus and method include a cooling mechanism in a wall of the apparatus that enhances radiation heat transfer between the glass and the wall of the apparatus and is tunable in both the vertical and horizontal directions. The apparatus and method also include a heating mechanism that affects radiation heat transfer between the glass and the wall of the apparatus, is tunable in both the vertical and horizontal directions, and is independently operable from the cooling mechanism.

A method and apparatus for manufacturing glass are provided. The apparatus is configured to draw a glass ribbon and includes an evaporator unit having a liquid reservoir configured to receive a working liquid. The apparatus further includes a heat transfer element configured to be placed in thermal contact with the working liquid received in the liquid reservoir. The heat transfer element is configured to cool the glass ribbon being drawn from the glass manufacturing apparatus by receiving radiant heat from the glass ribbon and transferring the heat to the working liquid received in the liquid reservoir, thereby transforming an amount of the working liquid to a vapor. The method includes drawing the glass ribbon, cooling the glass ribbon by radiating heat from the glass ribbon to the heat transfer element, and then transferring heat from the heat transfer element to the working liquid.

A forming body of a glass forming apparatus may include a first conduit comprising a first conduit wall and at least one slot in the first conduit wall, and a second conduit disposed above and vertically aligned with the first conduit, the second conduit comprising a second conduit wall and a slot extending through the second conduit wall. The forming body may include a first vertical wall and a second vertical wall extending between an outer surface of the second conduit wall and an outer surface of the first conduit wall at a first side and a second side, respectively, of the forming body. The forming body may include a first forming surface and a second forming surface extending from an outer surface of the first conduit wall and converging at a root of the forming body. Methods of forming a continuous laminate glass ribbon are also disclosed.

A forming body of a glass forming apparatus may include a first conduit comprising a first conduit wall and at least one slot in the first conduit wall, and a second conduit disposed above and vertically aligned with the first conduit, the second conduit comprising a second conduit wall and a slot extending through the second conduit wall. The forming body may include a first vertical wall and a second vertical wall extending between an outer surface of the second conduit wall and an outer surface of the first conduit wall at a first side and a second side, respectively, of the forming body. The forming body may include a first forming surface and a second forming surface extending from an outer surface of the first conduit wall and converging at a root of the forming body. Methods of forming a continuous laminate glass ribbon are also disclosed.

The method for producing a glass sheet by down-drawing includes an air pressure controlling step of controlling the air pressure of a furnace outside space formed between a furnace and a covering part that covers the furnace, the furnace including a forming furnace and a lehr, a melting step of melting glass raw materials to form molten glass, a supplying step of supplying the molten glass to a forming cell disposed inside the forming furnace, a forming step of forming a glass sheet by allowing the molten glass to flow down the forming cell, an annealing step of cooling the glass sheet while allowing the glass sheet to flow in one direction in the lehr, and a cutting step of cutting the glass sheet that has been cooled. In the air pressure controlling step, air pressure is controlled such that the air pressure is higher, inside the furnace outside space, at a position more toward the upstream side of the flow direction of the glass sheet.

The method for producing a glass sheet by down-drawing includes an air pressure controlling step of controlling the air pressure of a furnace outside space formed between a furnace and a covering part that covers the furnace, the furnace including a forming furnace and a lehr, a melting step of melting glass raw materials to form molten glass, a supplying step of supplying the molten glass to a forming cell disposed inside the forming furnace, a forming step of forming a glass sheet by allowing the molten glass to flow down the forming cell, an annealing step of cooling the glass sheet while allowing the glass sheet to flow in one direction in the lehr, and a cutting step of cutting the glass sheet that has been cooled. In the air pressure controlling step, air pressure is controlled such that the air pressure is higher, inside the furnace outside space, at a position more toward the upstream side of the flow direction of the glass sheet.