Abstract: The present invention relates to a glass for a pharmaceutical container that is excellent in ultraviolet shielding ability, and is also excellent in chemical durability. The glass for a pharmaceutical container of the present invention includes as a glass composition, in terms of mass %, 67% to 81% of SiO2, more than 4% to 7% of Al2O3, 7% to 14% of B2O3, 3% to 12% of Na2O+K2O, 0% to 1.8% of CaO+BaO, 0.5% to less than 2% of Fe2O3, and 1% to 5% of TiO2, and satisfies a relationship of CaO/BaO?0.5.

Abstract: A prefiner (28) is described and includes a chamber (34) for receiving molten glass exiting a submerged combustion melter. The prefiner (28) also includes a foam breaker (36) and an exit conduit (38). The molten glass holding chamber includes a top portion (42), a bottom portion (40), and an enclosing sidewall (44). The top portion (42) includes an opening to accommodate the foam breaker (36), which is positioned to break the glass bubbles within the chamber. The exit conduit (38) resides within the chamber (34) and is in fluid communication with an outlet (68) in the sidewall (44). The exit conduit (38) is positioned to permit molten glass to flow from the lower section of the chamber to the outlet (68) and to the next stage of processing, typically a finer.

Abstract: Submerged combustion systems and methods of use to produce glass. One system includes a submerged combustion melter having a roof, a floor, a wall structure connecting the roof and floor, and an outlet, the melter producing an initial foamy molten glass. One or more non-submerged auxiliary burners are positioned in the roof and/or wall structure and configured to deliver combustion products to impact at least a portion of the bubbles with sufficient force and/or heat to burst at least some of the bubbles and form a reduced foam molten glass.

Abstract: Submerged combustion systems and methods of use to produce glass. One system includes a submerged combustion melter having a roof, a floor, a wall structure connecting the roof and floor, and an outlet, the melter producing an initial foamy molten glass. One or more non-submerged auxiliary burners are positioned in the roof and/or wall structure and configured to deliver combustion products to impact at least a portion of the bubbles with sufficient force and/or heat to burst at least some of the bubbles and form a reduced foam molten glass.

Abstract: A float glass furnace includes a melting furnace which heats raw materials to form a molten glass batch, a working end where the molten glass batch is cooled, at least one regenerator which introduces heated combustion air into the melting furnace through a port neck, and at least one oxygen lance in or proximate the port neck. The oxygen lance includes a lance pipe in fluid communication with the port neck, an outer shell surrounding the lance pipe, an inlet water passageway in fluid communication with a channel(s) between an exterior surface of the lance pipe and an interior surface of the outer shell, and an outlet water passageway in fluid communication with the channel(s).

Abstract: A vacuum degassing apparatus for molten glass is comprised of an uprising pipe, a vacuum degassing vessel, a downfalling pipe, an upstream side pit that supplies molten glass to the uprising pipe, and a downstream side pit that receives molten glass from the downfalling pipe. The vacuum degassing apparatus for molten glass is further comprised of a separating mechanism that separates a part of molten glass moving from the downfalling pipe to the downstream side pit, and a returning pipe that returns separated molten glass to the upstream side pit.

Abstract: Methods and systems for controlling bubble size and bubble decay rate of glass foams formed during submerged combustion melting. Flowing a molten mass of foamed glass comprising molten glass and bubbles entrained therein into an apparatus downstream of a submerged combustion melter. The downstream apparatus has a floor, a roof, and a sidewall structure connecting the floor and roof. The foamed glass has glass foam of glass foam bubbles on its top surface, and the downstream apparatus defines a space for a gaseous atmosphere above and in contact with the glass foam. The downstream apparatus includes heating components to heat or maintain temperature of the foamed glass. Adjusting composition of the atmosphere above the glass foam, and/or contacting the foam with a liquid or solid composition controls bubble size of the glass foam bubbles, and/or foam decay rate.

Abstract: A process for making silica-based glass includes: (a) forming a glass precursor melt that includes glass network formers and glass network modifiers, the glass precursor melt being at a temperature in the range of 900 C to 1700 C and having a viscosity of not more than 3 Pa·s, and (b) refining the glass precursor melt. Either or both steps (a) and (b) can include stirring and/or be carried out under reduced pressure to enhance refining. The refined glass precursor melt preferably is mixed with additional materials including silica (SiO2) to form a silica-based glass melt.

Abstract: A process and an apparatus for refining molten glass by introducing, a stream of unrefined molten glass into a controlled environment distributing the stream of molten glass over a flow surface, and collecting the stream of molten glass from a downstream end of the flow surface to form a body of molten glass having a free surface exposed to the controlled environment. The controlled environment, may have a pressure less than ambient atmospheric pressure, such that introducing the stream of molten glass into the controlled environment causes gaseous inclusions in the stream of molten glass to rise to a surface thereof and escape.

Abstract: Methods and systems produce a molten mass of foamed glass in a submerged combustion melter (SCM). Routing foamed glass to a fining chamber defined by a flow channel fluidly connected to and downstream of the SCM. The flow channel floor and sidewalls have sufficient glass-contact refractory to accommodate expansion of the foamed glass as fining occurs during transit through the fining chamber. The foamed glass is separated into an upper glass foam phase and a lower molten glass phase as the foamed glass flows toward an end of the flow channel distal from the SCM. The molten glass is then routed through a transition section fluidly connected to the distal end of the flow channel. The transition section inlet end construction has at least one molten glass inlet aperture, such that the inlet aperture(s) are positioned lower than the phase boundary between the upper and lower phases.

Abstract: Hydrogen may permeate into an interior space of an article in response to molten glass being in contact with the outer surface of the article. The permeation may be restricted by having a fluid in a length of the interior space. The fluid may be in contact with the inner surface of the article, the fluid may fill at least about 33% of the volume of the length of the interior space, and the fluid may provide a predetermined partial pressure of hydrogen. Features may be provided for causing the fluid to flow within the interior space.

Abstract: Channel apparatus for use with submerged combustion systems and methods of use to produce glass. One channel apparatus includes a flow channel defined by a floor, a roof, and a wall structure connecting the floor and roof, the flow channel divided into sections by a series of skimmers. Channel apparatus include both high and low momentum combustion burners, with one or more high momentum combustion burners positioned immediately upstream of each skimmer in either the roof or sidewall structure, or both, and one or more low momentum combustion burners positioned immediately downstream of each skimmer in either the roof, the sidewall structure, or both, and positioned to transfer heat to the molten mass of glass without substantial interference from foamed material. Certain embodiments include increased height of glass-contact refractory, in particular immediately upstream of the skimmers.

Abstract: A glass-melting device for producing glass fibers capable effectively reducing inclusion of bubbles into glass fibers to be spun, and a method for producing glass fibers using the same are provided. A glass-melting device 100 for producing glass fibers comprises: a first glass-melting tank 12; a conduit 14 extending downward from the first glass-melting tank 12; a sucking device 18 for exposing the first glass-melting tank 12 to a reduced-pressure atmosphere; a second glass-melting tank 20 provided on a lower portion of the conduit 14 and exposed to an atmospheric-pressure atmosphere; and a bushing 22 provided at a bottom portion of the second glass-melting tank 20 and equipped with a number of nozzles 22a.

Abstract: Methods and systems for de-stabilizing foam produced in submerged combustion melters. A molten mass of glass and bubbles is flowed into an apparatus downstream of a submerged combustion melter. The downstream apparatus includes a floor, a roof and a wall connecting the floor and roof, but is devoid of submerged combustion burners and other components that would increase turbulence of the molten mass. The molten mass has foam on at least a portion of a top surface of the molten mass. Certain methods include imposing a de-stabilizing force directly to the foam or to the molten mass and foam, where the de-stabilizing force may be a vibratory force, an acoustic wave force, a particulate-based force, or a non-particulate-based mechanical force. Systems for carrying out the methods are described.

Abstract: Methods and systems for controlling bubble size and bubble decay rate of glass foams formed during submerged combustion melting. Flowing a molten mass of foamed glass comprising molten glass and bubbles entrained therein into an apparatus downstream of a submerged combustion melter. The downstream apparatus has a floor, a roof, and a sidewall structure connecting the floor and roof. The foamed glass has glass foam of glass foam bubbles on its top surface, and the downstream apparatus defines a space for a gaseous atmosphere above and in contact with the glass foam. The downstream apparatus includes heating components to heat or maintain temperature of the foamed glass. Adjusting composition of the atmosphere above the glass foam, and/or contacting the foam with a liquid or solid composition controls bubble size of the glass foam bubbles, and/or foam decay rate.

Abstract: A method of manufacturing glass comprises a stirring step in which molten glass MG is stirred. The stirring step comprises a first stirring step and a second stirring step. In the first stirring step, the molten glass MG is stirred while being directed upward from below in a first stirred tank 100a. In the second stirring step, the molten glass MG stirred in the first stirring step is stirred while being directed downward from above in a second stirred tank 100b. The first stirred tank 100a has a first discharge pipe 110a capable of discharging the molten glass MG from the bottom of a first chamber 101a. The second stirred tank 100b has a second discharge pipe 110b capable of discharging the molten glass MG from the liquid level LL of the molten glass MG in a second chamber 101b.

Abstract: Channel apparatus for use with submerged combustion systems and methods of use to produce glass. One channel apparatus includes a flow channel defined by a floor, a roof, and a wall structure connecting the floor and roof, the flow channel divided into sections by a series of skimmers. Channel apparatus include both high and low momentum combustion burners, with one or more high momentum combustion burners positioned immediately upstream of each skimmer in either the roof or sidewall structure, or both, and one or more low momentum combustion burners positioned immediately downstream of each skimmer in either the roof, the sidewall structure, or both, and positioned to transfer heat to the molten mass of glass without substantial interference from foamed material. Certain embodiments include increased height of glass-contact refractory, in particular immediately upstream of the skimmers.

Abstract: A vacuum degassing apparatus for molten glass is comprised of an uprising pipe, a vacuum degassing vessel, a downfalling pipe, an upstream side pit that supplies molten glass to the uprising pipe, and a downstream side pit that receives molten glass from the downfalling pipe. The vacuum degassing apparatus for molten glass is further comprised of a separating mechanism that separates a part of molten glass moving from the downfalling pipe to the downstream side pit, and a returning pipe that returns separated molten glass to the upstream side pit.

Abstract: Submerged combustion systems and methods of use to produce glass. One system includes a submerged combustion melter having a roof, a floor, a wall structure connecting the roof and floor, and an outlet, the melter producing an initial foamy molten glass. One or more non-submerged auxiliary burners are positioned in the roof and/or wall structure and configured to deliver combustion products to impact at least a portion of the bubbles with sufficient force and/or heat to burst at least some of the bubbles and form a reduced foam molten glass.

Abstract: A foam and frothy glass mixture that forms on a pool of molten glass and inhibits heat transfer between the overhead flames and the pool of molten glass is decreased, if not eliminated, by spreading a glass fluxing agent, e.g. but not limiting to the invention, sodium sulfate over the foam and/or frothy glass mixture.

Abstract: A vacuum degassing apparatus for molten glass is comprised of an uprising pipe, a vacuum degassing vessel, a downfalling pipe, an upstream side pit that supplies molten glass to the uprising pipe, and a downstream side pit that receives molten glass from the downfalling pipe. The vacuum degassing apparatus for molten glass is further comprised of a separating mechanism that separates a part of molten glass moving from the downfalling pipe to the downstream side pit, and a returning pipe that returns separated molten glass to the upstream side pit.

Abstract: The neutral glass according to the present invention is characterized by excellent hydrolytic stability, a relatively low processing temperature and low content of boron oxide. Here, the neutral glass has the following composition, in percent by weight based on oxide content: SiO2, 70-79; B2O3, 0-<5; Al2O3, <5; ZrO2, 0.5-<5; TiO2, 0.5-6; Na2O, 1-6; K2O, 3 to 8; and Li2O, 0-0.5, wherein a total amount of SiO2 and B2O3 is less than 83 percent by weight.

Abstract: A method for removing gaseous inclusions from a viscous liquid in which a viscous liquid stream having gaseous inclusions is introduced into a refining chamber, resulting in a flowing viscous liquid layer. The viscosity of a bottom portion of the viscous liquid layer is reduced in a first refining zone in the refining chamber so as to produce an upwardly mobile reduced viscosity portion of the viscous liquid layer. Heat is introduced into the viscous liquid layer from above the viscous liquid layer in a second refining zone in the refining chamber downstream of the first refining zone, reducing the gaseous inclusions in said viscous liquid layer. Thereafter, the viscous liquid layer having substantially reduced gaseous inclusions is discharged from the refining chamber.

Abstract: The float glass apparatus has a glass melt producing unit including a melting tank and a refining tank for the glass melt, a float tank including a metallic basin and metal bath contained in the basin, conducting devices for conducting the glass melt from the glass melt producing unit to the metal bath and auxiliary devices as needed. In order to minimize bubble defects and extend service life of apparatus parts made from platinum or a platinum alloy, the apparatus includes a device for minimizing direct current flowing between the glass melt producing unit and the float tank, which includes an auxiliary electrode connected with ground and located in the glass melt producing unit in electrical contact with the glass melt and a direct electrical connection between the metallic basin of the float tank and ground.

Abstract: A method for reducing gaseous inclusions in high melting temperature or high strain point glasses is described. The method includes heating a batch material within a melting vessel to form molten glass at a melting temperature TM, the molten glass comprising a multivalent oxide material; heating the molten glass within a fining vessel to a fining temperature TF?TM; and cooling the molten glass within a refractory tube after the first or second heating step to a cooling temperature TC less than TM. The molten glass remains within the refractory tube for a time sufficient to reduce a volume of gaseous inclusions in the molten glass and cause gas species to migrate out of the gaseous inclusions into the molten glass such that at least a portion of the gaseous inclusions collapse into the molten glass.

Abstract: A process for producing silicon which comprises: bringing molten silicon containing an impurity into contact with molten salt in a vessel to react the impurity contained in the molten silicon with the molten salt; removing the impurity from the system.

Abstract: Provided is a method of producing a glass, including, in order to obtain an excellent refining effect: preparing a raw glass batch including: an antimony compound containing pentavalent antimony; and an oxidizing agent (a cerium oxide, a sulfate, a nitrate); and melting the raw glass batch. In preparing the raw glass batch, it is preferable that the antimony compound be premixed with the oxidizing agent. When the nitrate is used as the oxidizing agent, the raw glass batch is prepared so as to include the antimony compound in an amount of more than 0.5 parts by mass and at most 3 parts by mass, in terms of an amount of antimony pentoxide, per 100 parts by mass of a base glass composition expressed in terms of an amount of an oxide.

Abstract: The present invention relates to a method of refining lithium aluminosilicate glass capable of being controllably ceramized and free of arsenic oxide, antimony oxide and tin oxide, in which at least 0.05% by weight of at least one sulfide is added to the glass batch materials and said materials are melted at a temperature below 1750° C. The invention also relates to the glass-ceramics obtained from said colored glass, especially glass colored by vanadium oxide, and cooktops and cooking utensils including such glass-ceramics.

Abstract: It is an object of the present invention to provide a method and apparatus for efficiently remove bubbles present on a surface of molten glass, which can solve a problem that bubbles remaining on a surface of molten glass are get inside at a time of forming the glass to cause inside bubbles, to thereby provide a glass substrate of good quality, and which can improve productivity of glass substrates; and to provide a process for producing glass employing the above method for removing bubbles. The present invention provides a method for removing bubbles from molten glass, which is a method for removing floating bubbles on a surface of molten glass, wherein a floating bubble on the surface of molten glass is irradiated with at least one laser beam.

Abstract: Methods are provided for controlling the formation of defects in sheet glass produced by a fusion process which employs a zirconia melting unit. The methods comprise controlling the temperature profile of the glass as it passes through the finer, finer to stir chamber connecting tube, and stir chamber to minimize both the amount of zirconia which diffuses into the glass and the amount of secondary zirconia based defects which comes out of solution in the stir chamber.

Abstract: In the process of producing a glass, a glass melt is formed from an initial glass batch, an inorganic or organic peroxide is include in the glass melt as a refining agent in an amount suitable for refining, and then the glass melt is refined at a refining temperature equal to or greater than a decomposition temperature of the inorganic or organic peroxide. The inorganic peroxides used in the glass-making process only include cations that are already present in components of the initial glass batch. The organic peroxides used in the glass-making process are chosen so that the organic residue remaining in the melt after release of oxygen is decomposed to volatile water and CO2.

Abstract: A method for removal of gaseous inclusions from a viscous liquid in which a layer of filter particles is positioned in the viscous liquid and the viscous liquid is passed through the layer of filter particles, whereby the gaseous inclusions combine or coalesce within the layer of filter particles, forming larger gaseous inclusions which rise to the top of the viscous liquid and escape therefrom.

Abstract: A glass manufacturing system and a method are described herein for reducing gaseous inclusions in high melting temperature or high strain point glasses, such as those that are used as glass substrates in flat panel display devices. In one embodiment, the method including the steps of: (a) heating a batch material within a melting vessel to form molten glass at a melting temperature TM, the molten glass comprising a multivalent oxide material; (b) heating the molten glass within a fining vessel to a fining temperature TF?TM; and (c) cooling the molten glass within a refractory tube after the first heating step or after the second heating step to a cooling temperature TC less than TM, where the molten glass remains within the refractory tube for a predetermined resident time to reduce a volume of the gaseous inclusions in the molten glass and cause gas species to migrate out of the gaseous inclusions into the molten glass such that at least a portion of the gaseous inclusions collapse into the molten glass.

Abstract: A backup structure for an uprising pipe or a downfalling pipe of a vacuum degassing apparatus including the uprising pipe, a vacuum degassing vessel and the downfalling pipe, comprises the uprising pipe or the downfalling being made of platinum or a platinum alloy and having refractory bricks disposed therearound; and the refractory bricks having a thermal expansion relief member disposed on a top end thereof, the thermal expansion relief member comprising a material selected from a metal material and a ceramic material having a creep strength (JIS Z2271: 1993) of 35 MPa or above at 760° C.

Abstract: A process for producing a high-quality glass from highly reactive raw materials and a glass-melting apparatus for use therewith, comprising the step of charging a material for the glass to a molten glass in a heated vessel, (1) wherein an oxidizing gas is bubbled in the molten glass and a glass raw material that behaves as a reducing agent during being melted is charged into a position of the bubbling or (2) said vessel is filled with a dry ambient gas and while the ambient gas is allowed to flow to a liquid surface of the molten glass along an charging route of the glass raw material, the glass raw material is charged.

Abstract: A vacuum degassing apparatus for molten glass includes a vacuum housing which is evacuated to be depressurized therein; a vacuum degassing vessel which is provided in the vacuum housing to vacuum-degas molten glass as the molten glass flows therein; an uprising pipe which connects to the vacuum degassing vessel, and sucks and draws up undegassed molten glass to introduce the undegassed molten glass into the vacuum degassing vessel; and a downfalling pipe which connects to the vacuum degassing vessel and draws down the degassed molten glass from the vacuum degassing vessel to discharge the degassed molten glass. The cross sectional area of the path at the upper end portion of the uprising pipe is larger than the cross sectional area of the path at the lower end portion of the uprising pipe.

Abstract: In the case of a method for manufacturing glass, with which molten glass is enclosed at least partially by precious metal walls or refractory metal walls, and with which the oxygen partial pressure of the molten glass is influenced by a treatment means to prevent disturbances, gas bubbles or other disturbances often form as a result of over-compensation. This over-compensation can be prevented by locating at least one probe (20) for determining the oxygen partial pressure at the interface—or close to the interface—of the glass melt and metal wall, and by regulating the influencing of the oxygen partial pressure in a safe range of the oxygen partial pressure with the treatment means using a regulating system (39, 45).

Abstract: A process for melting and refining vitrifiable materials, such that all or part of the thermal energy necessary for melting the said vitrifiable materials is supplied by the combustion of fossil fuel(s) with at least one oxidizer gas, the fuel(s)/gas or the gaseous products resulting from the combustion being injected below the level of the mass of vitrifiable materials (7). The refining of the vitrifiable materials after melting comprises at least one step of subjecting them to subatmospheric pressure while centrifuging.

Abstract: A method for removal of gaseous inclusions from a viscous liquid in which a layer of filter particles is positioned in the viscous liquid and the viscous liquid is passed through the layer of filter particles, whereby the gaseous inclusions combine or coalesce within the layer of filter particles, forming larger gaseous inclusions which rise to the top of the viscous liquid and escape therefrom.

Abstract: The subject of the invention is a process for melting and refining vitrifiable materials, such that all or part of the thermal energy necessary for melting the said vitrifiable materials is supplied by the combustion of fossil fuel(s) with at least one oxidizer gas, the said fuel(s)/gas or the gaseous products resulting from the combustion being injected below the level of the mass of vitrifiable materials (7). The refining of the vitrifiable materials after melting takes place at least partly in the form of a “thin layer”. The invention also relates to the device for implementing the process and to its applications.

Abstract: It is an object of the present invention to provide a method and apparatus for efficiently remove bubbles present on a surface of molten glass, which can solve a problem that bubbles remaining on a surface of molten glass are get inside at a time of forming the glass to cause inside bubbles, to thereby provide a glass substrate of good quality, and which can improve productivity of glass substrates; and to provide a process for producing glass employing the above method for removing bubbles. The present invention provides a method for removing bubbles from molten glass, which is a method for removing floating bubbles on a surface of molten glass, wherein a floating bubble on the surface of molten glass is irradiated with at least one laser beam.

Abstract: In some embodiments, the invention provides a refining chamber for glass production, made of platinum group metal materials, with improved refining effectiveness. The refining chamber according has the shape of a tube with a cross section (1), with the cross section of the tube being shaped, in at least one segment, so that in the operating position the length (10) of a horizontal line (12) which divides the surface of the cross section into essentially a lower and an upper segment of the surface, both of which have essentially the same area, is greater than twice the maximum vertical extent (30) of the lower segment of the surface. The cross section of the refining chamber can, for example, have the shape of an oval, an ellipse, a slot, a rounded triangle or a polygon, and the stiffness of the shape of the refining chamber can be increased by forming radially peripheral creases, corners, waves or folds.

Abstract: A melter including an upper chamber configured to receive marbles or the like, and a lower chamber separated from the upper chamber by a porous wall through which, as the result of heating, glass marbles or the like liquefy in the form of a batch. The upper and lower chambers define a melting zone. A refining zone is fed via at least one channel emerging from the melting zone.

Abstract: A method of forming an oxide glass including heating a glass melt having a ?—OH concentration of at least about 0.35 in a vessel comprising a metal selected from the group consisting of platinum, molybdenum, palladium, rhodium, and alloys thereof, there being an interface present between the vessel and the glass, and controlling a partial pressure of hydrogen in an atmosphere in contact with an outside surface of the vessel in an amount such that hydrogen permeation blisters form in a region of the glass adjacent the glass-vessel interface.

Abstract: Bubbles of uniform diameter of 0.5 to 4 cm of gas such as helium are formed and pass into liquid such as molten glass by accumulating a sufficient volume of gas through a flow restriction into a space upstream of the point of injection at a controlled flow rate.

Abstract: A method of manufacturing glass melt and a method of manufacturing molded glass material by forming glass melt. In the method of manufacturing glass melt, the glass melt containing fluorine is prepared by melting glass raw materials and refining the resulting glass melt. The refining is conducted in a refining vat equipped with a flow inlet through which flows glass melt obtained by heating and melting the glass raw materials, and a flow outlet through which flows glass melt that has been refined, with the level of the glass melt being maintained in such a manner that the flow inlet and flow outlet remain beneath the surface of the glass melt and the glass melt does not contact external air. The method of manufacturing a molded glass material comprises the step of molding the glass melt produced by the above method.

Abstract: To provide a process for producing and alkali free glass for effectively suppressing bubbles, and an alkali free glass produced by the process, which is suitable as a glass substrate for flat panel displays and has few bubbles. A process for producing an alkali free glass containing substantially no alkali metal oxide, which comprises melting a glass starting material having a matrix composition of the following composition, and subjecting the molten glass to a treatment process of removing bubbles under reduced pressure, stirring or transferring under a condition where the molten glass is in contact with a platinum member, wherein the starting material is prepared so as to contain SnO2 in an amount of from 0.01 to 2.0% per 100% of the total amount of the above matrix composition; the starting material is melted under heating at from 1,500 to 1,650° C.

Abstract: The present invention provides a A metal conduit for molten glass and a vacuum degassing apparatus are disclosed, which are capable of coping with extension and contraction, and vibration. By disposing at least one convex portion 20 so to have a height of 4 mm or above in a radial direction and continuously extend in a peripheral direction, it is possible to absorb thermal expansion and contraction without changing the entire length of the metal conduit 10 and to suppress from the metal conduit 10 from vibrated even when molten glass 121 is conveyed by the metal conduit. By employing the metal conduit 10 stated earlier in an upstream conveying pipe 130A, an uprising pipe 122U, a vacuum degassing vessel 120, a downfalling pipe 122L, a downstream conveying pipe 130B or the like in a vacuum degassing apparatus 30, it is possible to cope with thermal expansion and contraction, and vibration caused when conveying molten glass 121.

Abstract: A conduit for molten glass, a molten glass degassing method and a sub-atmospheric apparatus are provided, which are able to produce homogenous and good quality glass at low cost. A conduit for molten glass, which is capable of flowing molten glass in a horizontal direction, and to which vertical pipes are connectable, is disposed in a substantially horizontal direction. The conduit for molten glass can increase the area of a free surface of the molten glass by setting a width W at a larger value than a height H in cross-section and having an outline in cross-section comprising a convex curve. When the conduit for molten glass thus configured is used as a sub-atmospheric apparatus, it is possible to degas the molten glass effectively. Additionally, it is possible to have a sufficient strength since the convex curve forming the cross-section is elliptical. Further, it is possible to reduce costs by decreasing the amount of metal required for forming the cross-section.

Abstract: The apparatus for reduced-pressure refining of a glass melt includes a refining bank formed so that a reduced pressure is generated by a glass flow in it. The refining bank has a component, which is made from a refractory metal or refractory alloy acting as glass-contact material. The refractory metal or alloy contains molybdenum, tungsten, tantalum, and/or hafnium. The device of the present invention includes a protective gas reservoir for a protective gas and an automatically operating valve connecting the reservoir with the refining bank so that an inner side of the component that would otherwise be exposed when a pressure rise or a falling glass melt column occurs is protected from oxidation by the protective gas. A process for using the device during refining of the glass melt is also part of the invention.