An apparatus for processing a quantity of glass melt comprises a segmented tube including a first tube segment and a second tube segment. A second end portion of the first tube segment is joined to a first end portion of the second tube segment. In further examples, methods of fabricating a segmented torsion tube include joining together segmented torsion tubes at an integral solid-state joint.

An apparatus for processing a quantity of glass melt comprises a segmented tube including a first tube segment and a second tube segment. A second end portion of the first tube segment is joined to a first end portion of the second tube segment. In further examples, methods of fabricating a segmented torsion tube include joining together segmented torsion tubes at an integral solid-state joint.

The present invention relates to a float glass substrate including an alkali-free glass, the float glass substrate having a Cl content of from 0.10 to 0.50 mass %, containing substantially no SnO.sub.2, and having a Pt content of, by mass, from 0.001 to 0.30 ppm. The float glass substrate may have a Rh content of, by mass, from 0.001 to 0.50 ppm.

The present invention provides for synthesizing high optical quality multicomponent chalcogenide glasses without refractive index perturbations due to striae, phase separation or crystal formation using a two-zone furnace and multiple fining steps. The top and bottom zones are initially heated to the same temperature, and then a temperature gradient is created between the top zone and the bottom zone. The fining and cooling phase is divided into multiple steps with multiple temperature holds.

The present invention provides for synthesizing high optical quality multicomponent chalcogenide glasses without refractive index perturbations due to striae, phase separation or crystal formation using a two-zone furnace and multiple fining steps. The top and bottom zones are initially heated to the same temperature, and then a temperature gradient is created between the top zone and the bottom zone. The fining and cooling phase is divided into multiple steps with multiple temperature holds.

A method of controlling a flowrate of molten material at a downstream location in a glass manufacturing process can include mixing the molten material at an upstream location positioned upstream from the downstream location relative to a flow direction of the molten material with a shaft including a plurality of protrusions. The method can also include measuring a torque of the shaft, measuring a level of the molten material at the upstream location, and calculating a viscosity of the molten material at the upstream location based on the measured torque and the measured level. In addition, the method can include estimating the flowrate based on the calculated viscosity, and controlling the flowrate at the downstream location based on the estimated flowrate.

Provided are a refractory article, an anti-redox coating composition, and a method of manufacturing the refractory article. The refractory article includes: a platinum(Pt)-based substrate; and a coating layer for preventing a redox reaction on a surface of the Pt-based substrate, wherein the coating layer for preventing a redox reaction includes on an oxide basis SiO.sub.2 in an amount of about 40 wt % to about 70 wt %, Al.sub.2O.sub.3 in an amount of about 20 wt % to about 52 wt %, B.sub.2O.sub.3 in an amount of about 3 wt % to about 6 wt %; and CaO in an amount of about 2.4 wt % to about 4.8 wt %.

Provided are a refractory article, an anti-redox coating composition, and a method of manufacturing the refractory article. The refractory article includes: a platinum(Pt)-based substrate; and a coating layer for preventing a redox reaction on a surface of the Pt-based substrate, wherein the coating layer for preventing a redox reaction includes on an oxide basis SiO.sub.2 in an amount of about 40 wt % to about 70 wt %, Al.sub.2O.sub.3 in an amount of about 20 wt % to about 52 wt %, B.sub.2O.sub.3 in an amount of about 3 wt % to about 6 wt %; and CaO in an amount of about 2.4 wt % to about 4.8 wt %.

A method of manufacturing a glass article includes flowing molten glass through a first vessel to a downstream second vessel, the molten glass flowing through a conduit connecting the first vessel to the second vessel, the first vessel and the conduit defining a continuous free volume above a free surface of the molten glass extending into at least a portion of the conduit. The method further includes venting a first atmosphere contained in the free volume to a second atmosphere external to the first vessel through a vent tube connected to the conduit proximate a top of the conduit and above the free surface, the vent tube extending downward from the conduit to a distal end of the vent tube along a longitudinal axis at an angle a relative to horizontal and providing fluid communication between the first atmosphere and the second atmosphere.