A batch charger includes a barrel defining a direction X of charging a glass forming batch into the furnace, and a mechanical assembly provided with a member for conveying the batch to the furnace in the charging direction X, this conveying member being at least partially arranged in the barrel, and a motorized unit for driving the conveying member. The batch charger includes a mechanical assembly translatably mobile relative to the barrel, in the charging direction X.

A low-NOx end-fired furnace for melting glass equipped with an overhead burner includes an inlet duct for oxidizer, including 15% to 30% of oxygen, in its upstream wall, a duct for receiving the combustion flue gases in its upstream wall, and a sonic injection system including at least one injector for injecting a jet of a gas at a speed at least equal to 80% of the speed of sound, referred to as a sonic injector, opening into the upstream wall or opening into the duct for receiving the combustion flue gases, the sonic injector injecting its gas counter-current to the stream of the combustion flue gases that are heading toward the duct for receiving the combustion flue gases.

A low-NOx end-fired furnace for melting glass equipped with an overhead burner includes an inlet duct for oxidizer, including 15% to 30% of oxygen, in its upstream wall, a duct for receiving the combustion flue gases in its upstream wall, and a sonic injection system including at least one injector for injecting a jet of a gas at a speed at least equal to 80% of the speed of sound, referred to as a sonic injector, opening into the upstream wall or opening into the duct for receiving the combustion flue gases, the sonic injector injecting its gas counter-current to the stream of the combustion flue gases that are heading toward the duct for receiving the combustion flue gases.

An electrically boosted refractory melting vessel including a back wall, a first side wall, a second side wall, a front wall and a bottom wall, the melting vessel comprising a longitudinal center line extending from the back wall to the front wall and an overall width orthogonal to the longitudinal center line extending between an inside surface of the first side wall and an inside surface of the second side wall. The melting vessel also includes a length L between the back wall and the front wall, and a width W between the first side wall and the second side wall orthogonal to the center line. A plurality of electrodes extend into an interior of the melting vessel through a bottom wall of the melting vessel, and L/W is in a range from about 2.0 to about 2.4.

An electrically boosted refractory melting vessel including a back wall, a first side wall, a second side wall, a front wall and a bottom wall, the melting vessel comprising a longitudinal center line extending from the back wall to the front wall and an overall width orthogonal to the longitudinal center line extending between an inside surface of the first side wall and an inside surface of the second side wall. The melting vessel also includes a length L between the back wall and the front wall, and a width W between the first side wall and the second side wall orthogonal to the center line. A plurality of electrodes extend into an interior of the melting vessel through a bottom wall of the melting vessel, and L/W is in a range from about 2.0 to about 2.4.

A glass tank furnace and a glass melting method. The tank furnace comprises a melting portion. The melting portion comprises a melting tank. The melting tank is provided with at least one burner mounted on a crown. Each burner is provided with a gas fuel conduit for supplying gas fuel and an oxygen conduit for providing oxygen. A gas fuel flowmeter and a gas fuel control valve are provided on the gas fuel conduit. An oxygen flowmeter and an oxygen control valve are provided on the oxygen conduit. The gas fuel flowmeter, the gas fuel control valve, the oxygen flowmeter and the oxygen control valve are all connected with a control unit.

A glass tank furnace and a glass melting method. The tank furnace comprises a melting portion. The melting portion comprises a melting tank. The melting tank is provided with at least one burner mounted on a crown. Each burner is provided with a gas fuel conduit for supplying gas fuel and an oxygen conduit for providing oxygen. A gas fuel flowmeter and a gas fuel control valve are provided on the gas fuel conduit. An oxygen flowmeter and an oxygen control valve are provided on the oxygen conduit. The gas fuel flowmeter, the gas fuel control valve, the oxygen flowmeter and the oxygen control valve are all connected with a control unit.

Provided is an alkali-free glass substrate having a high strain point and excellent bubble count, and a method for manufacturing the alkali-free glass substrate. The method includes: a batch preparing process of preparing a raw material batch so as to obtain alkali-free glass containing, in mass %, 50 to 80% of SiO.sub.2, 15 to 30% of Al.sub.2O.sub.3, 0 to 4.5% of B.sub.2O.sub.3, 0 to 10% of MgO, 0 to 15% of CaO, 0 to 10% of SrO, 0 to 15% of BaO, 0 to 5% of ZnO, 0 to 5% of ZrO.sub.2, 0 to 5% of TiO.sub.2, 0 to 15% of P.sub.2O.sub.5 and 0 to 0.5% of SnO.sub.2 as a glass composition; a melting process of melting the prepared raw material batch; a fining process of fining the molten glass; and a forming process of forming the fined glass into a sheet shape. The raw material batch is melted such that a bubble enlarging temperature of the obtained glass is lower than a maximum temperature of the fining process.

A low-NOx end-fired furnace for melting glass equipped with an overhead burner includes an inlet duct for oxidizer, including 15% to 30% of oxygen, in its upstream wall, a duct for receiving the combustion flue gases in its upstream wall, and a sonic injection system including at least one injector for injecting a jet of a gas at a speed at least equal to 80% of the speed of sound, referred to as a sonic injector, opening into the upstream wall or opening into the duct for receiving the combustion flue gases, the sonic injector injecting its gas counter-current to the stream of the combustion flue gases that are heading toward the duct for receiving the combustion flue gases.

A low-NOx end-fired furnace for melting glass equipped with an overhead burner includes an inlet duct for oxidizer, including 15% to 30% of oxygen, in its upstream wall, a duct for receiving the combustion flue gases in its upstream wall, and a sonic injection system including at least one injector for injecting a jet of a gas at a speed at least equal to 80% of the speed of sound, referred to as a sonic injector, opening into the upstream wall or opening into the duct for receiving the combustion flue gases, the sonic injector injecting its gas counter-current to the stream of the combustion flue gases that are heading toward the duct for receiving the combustion flue gases.