A method of producing glass includes discharging an outflow (22, 1022) of fined molten glass from a fining tank (18, 1018) of a vacuum induction fining apparatus (10, 1010) and delivering the fined molten glass into a thermal conditioning tank (16, 1016) that is separated from the fining tank by an open space (26, 1026) occupied by an ambient environment (24, 1024). The fining tank includes a vertically-elongated housing (80, 1080) that defines an interior fining chamber (82, 1082) where a bath (76, 1076) of molten glass is collected and maintained. The interior fining chamber is maintained at subatmospheric pressure and the housing is surrounded by at least one induction coil (74, 1074) to introduce heat into the molten glass bath. The vacuum maintained in the interior fining chamber and the heating supplied by the induction coil(s) promote the ascension of gas bubbles upwards through the molten glass bath. A glass-producing system that includes the vacuum induction fining apparatus is also disclosed.

A large melting furnace suitable for borosilicate glass. Which has a melting area, a reinforcing area, an ascending area and a clarifying area. The melting area and the reinforcing area are separated by a partition wall, and a lower end of the partition wall goes deep below a surface of molten glass but is not in contact with a bottom of the melting furnace, so as to guarantee that the molten glass in the two areas is interconnected. The structures of the melting area and reinforcing area can also improve the problem of boron volatilization of the borosilicate glass caused by flame melting during a melting process. The molten glass flows out from a throat of the reinforcing area, passes through the ascending area and enters the shallower clarifying area.

An apparatus and process for making glass and glass gobs on demand. A sheet of molten glass is provided in a staging section. The sheet of molten glass is held within the staging section when there is no demand for glass articles. When there is a demand for production of glass articles, a portion of the sheet of molten glass is flowed into a gob forming section.

A glass melt production apparatus, which comprises a melting vessel, a vacuum degassing apparatus, a first conducting pipe structure connecting the melting vessel and the vacuum degassing apparatus, and a second conducting pipe structure to introduce a glass melt to a forming means, provided downstream the vacuum degassing apparatus; the vacuum degassing apparatus having an uprising pipe through which the glass melt from the melting vessel ascends, a vacuum degassing vessel, and a downfalling pipe through which the glass melt from the vacuum degassing vessel descends; the flow path of the glass melt in the uprising pipe, the vacuum degassing vessel and the downfalling pipe being made of a refractory material; the first conducting pipe structure having an upstream pit to supply the glass melt to the uprising pipe; and the second conducting pipe structure having a downstream pit containing the glass melt from the downfalling pipe; the glass melt production apparatus further comprising a third conducting pipe structure connecting the upstream pit and the downstream pit; and the third conducting pipe structure having a closing means to shut off a flow of the glass melt in the third conducting pipe structure; the third conducting pipe structure or the closing means having a glass melt flow path for emergencies, which allows the glass melt to pass therethrough, depending on the height of a liquid level of the glass melt in the third conducting pipe structure in the vicinity of the closing means.

A process and an apparatus for refining molten glass. The apparatus includes a porous body having an inlet, an outlet, and a plurality of pores through which molten glass can flow between the inlet and the outlet. The plurality of pores are defined by walls having wall surfaces that are configured to interact with the molten glass as the molten glass flows between the inlet and the outlet to help refine the molten glass.

An apparatus for melting and refining a silica-based glass composition includes a vertical first reaction chamber having an input adjacent to a lower end for receiving glass-forming components. The glass-forming components are heated to elevated temperature during upward flow through the vertical first reaction chamber to form a glass precursor melt adjacent to an upper end of the vertical first reaction chamber. A vertical second reaction chamber has an input adjacent to an upper end and an output adjacent to a lower end for delivering glass melt. A cross passage connects the upper end of the vertical first reaction chamber to the upper end of the vertical second reaction chamber such that the precursor melt flows from the vertical first reaction chamber through the cross passage and then through the vertical second reaction chamber to homogenize the precursor melt. Vacuum preferably is applied to the cross passage both to assist upward flow through the vertical first reaction chamber, and to assist refining of the precursor melt during such upward flow and during flow through the cross passage.

There are provided a conduit structure for molten glass, a vacuum degassing apparatus using the conduit structure, and a process for vacuum-degassing molten glass by use of the vacuum degassing apparatus, wherein without using a cooling system, solid thermal insulating materials constituting a backup for the conduit are prevented from being corroded by molten glass oozing out of a joint between adjacent fused cast refractories constituting the conduit, and wherein production cost is reduced. A conduit structure for molten glass, comprising a conduit and a backup disposed around the conduit; the conduit being a hollow pipe made of fused cast refractories disposed in longitudinal and circumferential directions thereof; the backup comprising a refractory layer outside the conduit, and a thermal insulating material layer disposed outside the refractory layer; the refractory layer including a refractory brick layer made by placing refractory bricks along the longitudinal and circumferential directions of the conduit, and a monolithic refractory layer formed by placing a monolithic refractory containing from 30 to 100% of Al.sub.2O.sub.3 and from 0 to 70% of SiO.sub.2 in percent by mass on an oxide basis and sintering the monolithic refractory; the thermal insulating material layer containing a solid thermal insulating material layer made of solid thermal insulating materials disposed along the longitudinal and circumferential directions of the conduit; the fused cast refractories constituting the conduit, the monolithic refractory forming the refractory brick layer and the refractory bricks constituting the refractory brick layer are selected such that the refractory layer contains a portion that has a temperature equal to the flow point of the molten glass when the molten glass passes through the conduit.

A process and an apparatus for refining molten glass. The apparatus includes a porous body having an inlet, an outlet, and a plurality of pores through which molten glass can flow between the inlet and the outlet. The plurality of pores are defined by walls having wall surfaces that are configured to interact with the molten glass as the molten glass flows between the inlet and the outlet to help refine the molten glass.

There is provided a process for producing molten glass, which is capable of easily increasing the H.sub.2O content in glass melt with excessive generation of convention of the glass melt being reduced.

One mode of the process for producing molten glass according to the present invention is characterized to include a material melting step for melting a raw glass material in a melting furnace to prepare glass melt; a water-molecules supply step for supplying a water-molecules supply gas into the glass melt flowing from an upstream end of the melting furnace toward a downstream end of the melting furnace; and a refining step for degassing, under a reduced pressure atmosphere, the glass melt flowing out of the downstream end; wherein a position where the water-molecules supply gas is supplied in the water-molecules supply step includes a first position and a second position from downstream to upstream in a flowing direction of the glass melt in this order; the first position is a position away from both of the upstream end and the downstream end; and the second position is a position closer to the upstream end than a center of a distance between the upstream end and the first position in the flowing direction of the glass melt.

To facilitate a preheating operation in a vacuum degassing apparatus having a flow path of a glass melt in an uprising pipe, a vacuum degassing vessel and a downfalling pipe constituted by a refractory material.

Flow of a glass melt G between a melting vessel 100 and an upstream pit 210 of a first conducting pipe structure connected to a vacuum degassing vessel 320 is shut off, and in a state where the flow of the glass melt G in a by-pass 500 for the glass melt G is shut off by a first closing means 220, a combustion gas from preheating burners 530, 540 is introduced to the by-pass 500 to preheat the flow path of the glass melt G in an uprising pipe 330, the vacuum degassing vessel 320 and a downfalling pipe 340.