Abstract: Provided is a manufacturing method for a glass article, including a melting step of generating molten glass (Gm) in a melting furnace (1), the melting furnace (1) being configured to heat the molten glass (Gm) through application of a current with an electrode (11) mounted to a bottom wall part (10).

Abstract: To provide a colored glass plate of which the mass ratio of divalent iron as calculated as Fe2O3 to total iron as calculated as Fe2O3 can be stably maintained at a high level while amber coloring derived from salt cake (Na2SO4) is suppressed by reducing the amount of salt cake used as a refining agent, and which has less bubbles regardless of a small amount of total sulfur as calculated as SO3. A colored glass plate which is made of alkali-containing silica glass containing iron, tin and sulfur, wherein, as represented by mass % based on oxides, the proportion of total sulfur as calculated as SO3 is less than 0.025%, the proportion of divalent iron as calculated as Fe2O3 to total iron as calculated as Fe2O3 is at least 45%, the proportion of divalent tin as calculated as SnO2 to total tin as calculated as SnO2 is at least 0.1% as represented by mol %, and ?-OH is at least 0.15 mm?1.

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: [Problem] The transmittance of glass can be dramatically improved as a result of this glass production method. In addition, the amount of rare metal, such as platinum, that melts into glass can be greatly reduced. [Solution] A glass production method whereby the water content in molten glass is increased, in a melting step (i) in which a glass raw material including at least one type of component among TiO2, Nb2O5, WO3, and Bi2O3 is heated inside a melting container and melted, and a molten glass is obtained.

Abstract: To provide laminated glass excellent in the quality and the cost, in which two glass plates differing in the plate thickness can easily be bent with good accuracy. Laminated glass 60 comprising a plurality of glass plates 12 and 14 bent into a predetermined shape, and an interlayer 40 interposed between the plurality of glass plates 12 and 14, at least two glass plates 12 and 14 among the plurality of glass plates 12 and 14 differing in the plate thickness, wherein the two glass plates 12 and 14 differing in the plate thickness have different glass compositions, and at an optional temperature between the annealing point and the softening point of the thick glass plate 12, the thick glass plate 12 has a lower viscosity than the thin glass plate 14.

Abstract: To provide a vacuum-degassing method and a vacuum degassing apparatus excellent in the effect of vacuum-degassing molten glass, more specifically, a method for vacuum-degassing molten glass and a vacuum degassing apparatus, capable of effectively suppressing formation of reboil bubbles. A method for vacuum-degassing molten glass, which comprises melting glass materials to be silicate glass and passing the resulting molten glass in a flow passage in a vacuum degassing vessel, the interior of which is maintained in a reduced pressure state, to vacuum-degas the molten glass, wherein vacuum-degassing is carried out under conditions satisfying the following formula (1) at a bottom portion of the vacuum degassing vessel: SS=pSO2/Pabs <2.0??(1) wherein SS is the supersaturation degree of SO2 in the molten glass, pSO2 is the partial pressure (Pa) of SO2, and Pabs is the pressure (Pa) at the bottom portion of the glass flow passage of the vacuum degassing vessel.

Abstract: Provided are a silicon purification apparatus that uses a ring-shaped thermal-insulating lid, which can be replaced while heating a crucible, as a thermal-insulating means for keeping the surface of a silicon melt at a high temperature, and has a simple structure and is easy to produce, said silicon purification apparatus being capable of continuously processing several tens of portions of charged silicon with the crucible heated as is; a silicon purification method that makes use of the silicon purification apparatus; and a purification method.

Abstract: Device (20) for purifying a molten material such as silicon, comprising a chamber (21) comprising a crucible (2; 15) for storing a molten material and a heating device (4) for heating the molten material contained in the crucible, the chamber being equipped with a device (22) for greatly lowering the pressure in the chamber, characterized in that it comprises at least one evaporator (10; 10, 10?) placed inside the chamber to receive part of the molten material, such that this molten material has a large interface with low-pressure vapour present in the chamber (21) to promote and accelerate the purification of the molten material.

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: The present invention is generally directed to a method of making chalcogenide glasses including holding the melt in a vertical furnace to promote homogenization and mixing; slow cooling the melt at less than 10° C. per minute; and sequentially quenching the melt from the top down in a controlled manner. Additionally, the present invention provides for the materials produced by such method. The present invention is also directed to a process for removing oxygen and hydrogen impurities from chalcogenide glass components using dynamic distillation.

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: In a method for producing a fluorophosphate optical glass comprising melting a glass raw material to give a molten glass, and refining, homogenizing and then quickly quenching the molten glass to produce the fluorophosphate optical glass, even if the glass is flown from a refining tank that is set to a high temperature to an operation tank that is set to a low temperature, bubbles are not generated in the glass. The content of Fe in terms of Fe2O3 and the content of Cu in terms of CuO is controlled so that the total of the contents of Fe and Cu is 20 ppm or more, and the obtained fluorophosphate optical glass has such transmittance property that the internal transmittance in terms of a thickness of 10 mm becomes 98% or more at a wavelength region of at least from 400 to 500 nm.

Abstract: A vacuum degassing apparatus having a throughput of at least 200 tons/day without causing problems such as a stagnation of molten glass flow in the molten glass flow path, an increment of flow rate of the molten glass flow in a local area, an excessive increment of pressure loss of the molten glass flow. A vacuum degassing apparatus comprises a vacuum degassing vessel, and an uprising pipe and a downfalling pipe which are connected with the vacuum degassing vessel, wherein the vacuum degassing vessel includes a wide portion for providing a molten glass flow path, and in the wide portion, the proportion W1/L1 of the breadth of molten glass flow path W1 to the length of molten glass flow path L1 is at least 0.

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 having a viscosity of not more than 30 Pa·s at 1300 C, 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 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: An object of the present invention is to effectively reduce mixing of bubbles into a spun glass fiber. A glass-melting device 10 for producing glass fibers includes; a first glass-melting tank 12 exposed to a reduced-pressure atmosphere; a second glass-melting tank 14 and a third glass-melting tank 16 arranged below the first glass-melting tank 12; an ascending conduit 18 that sends up molten glass resulting from melting in the second glass-melting tank 14 to deliver the molten glass to the first glass-melting tank 12; a descending conduit 20 that sends the molten glass down from the first glass-melting tank 12 to deliver the molten glass to the third glass-melting tank 16; a decompression housing 22; and a bushing 24. The glass-melting device 10 further includes heating means for separately heating the first glass-melting tank 12, the second glass-melting tank 14, the third glass-melting tank 16, the ascending conduit 18, the descending conduit 20 and the bushing 24.

Abstract: To provide a vacuum-degassing method and a vacuum degassing apparatus excellent in the effect of vacuum-degassing molten glass, more specifically, a method for vacuum-degassing molten glass and a vacuum degassing apparatus, capable of effectively suppressing formation of reboil bubbles. A method for vacuum-degassing molten glass, which comprises melting glass materials to be silicate glass and passing the resulting molten glass in a flow passage in a vacuum degassing vessel, the interior of which is maintained in a reduced pressure state, to vacuum-degas the molten glass, wherein vacuum-degassing is carried out under conditions satisfying the following formula (1) at a bottom portion of the vacuum degassing vessel: SS=pSO2/Pabs<2.0??(1) wherein SS is the supersaturation degree of SO2 in the molten glass, pSO2 is the partial pressure (Pa) of SO2, and Pabs is the pressure (Pa) at the bottom portion of the glass flow passage of the vacuum degassing vessel.

Abstract: A technology for removing impurities from a silicon raw material at a low cost. A base material made of metallurgical silicon is arranged in a dissolution vessel, the base material arranged in the dissolution vessel is heated in a vacuum ambience and fully molten, silicon is solidified from a portion where an inner bottom surface of the dissolution vessel is in contact with molten silicon by cooling the outer bottom surface of the dissolution vessel in a state where the outer bottom surface faces the cooling means, spaced from the cooling means, the solidificated silicon is made to grow upward, and unsolidificated silicon located above the solidificated silicon is removed from the dissolution vessel.

Abstract: A conduit structure for molten glass, in which molten glass is flown through a double-pipe structure, with little stress loading even for a long time operation. A supporting rib connecting an inner pipe and an outer pipe is employed in the double pipe structure having the inner pipe and outer pipe in the conduit structure for molten glass, wherein excessive stress concentration hardly occurs in an inner pipe-joint portion, an outer pipe-joint portion and the rib when the rib is applied with a stress load due to the weight of the inner pipe.

Abstract: This invention relates to a vacuum degassing vessel wherein even if bubbles of molten glass come into contact with an inner wall of an upper space of a vacuum degassing vessel to produce a molten glass flowing along the inner wall, a molten glass can be discharged to the outside of the vacuum degassing vessel, thereby performing vacuum degassing without deteriorating composition homogeneity of the molten glass.

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: 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 method for melting inorganic materials, preferably glasses and glass-ceramics, in a melting unit with cooled walls is provided. The method includes selecting the temperature of at least one region of the melt is selected in such a way as to be in a range from Teff?20% to Teff+20%, where the temperature Teff is given by the temperature at which the energy consumption per unit weight of the material to be melted is at a minimum, with the throughput having been selected in such a way as to be suitably adapted to the required residence time.

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: A process for making soda-lime glass includes calcinating calcium carbonate in solid phase and at elevated temperature to form calcium oxide and release gases such as carbon dioxide. Sodium silicate glass is formed separately in liquid phase while releasing gaseous reaction products. The calcium oxide and the sodium silicate glass intermediate products are mixed in liquid phase to form a soda-lime glass melt. Formation of sodium silicate glass as an intermediate product before mixing with the calcium oxide has the advantage of promoting release of gaseous reaction products in the sodium silicate due at least in part to the relatively low viscosity of the sodium silicate glass. The calcination step and/or the sodium silicate-forming step and/or the final mixing step can be carried out under reduced pressure further to promote release of gases and reduce bubble formation.

Abstract: There is provided an apparatus and method for making a glass preform with nanofiber reinforcement. The apparatus comprises a container for melting one or more glass components in a mixture comprising the glass components and one or more nanofibers. The container has an opening that allows escape of any gas released from the glass components when the glass components are melted in the container. The apparatus further comprises one or more heating elements for heating the container. The apparatus further comprises one or more electric field devices, positioned exterior to the glass components, that create an electric field in a volume of the mixture in order to orient the nanofibers within the glass components when the glass components are melted in the container.

Abstract: The present invention is a silicon refining apparatus including, in a reduced pressure vessel: a crucible capable of holding molten silicon; a heat-retaining lid capable of being placed over the crucible; and a heating device. The crucible has a lateral outer-circumferential portion provided with a first thermal-insulation material. The heat-retaining lid is a plate-like member made of carbon felt and provided with a carbon composite material at least on opposed main surfaces. The heat-retaining lid has opposed main surfaces with an opening formed to extend therethrough. The carbon composite material on the main surface of the heat-retaining lid on the crucible side is so placed as to cover an upper surface of the first thermal-insulation material when the heat-retaining lid is placed at an upper surface of the crucible.

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: A vacuum degassing apparatus having a throughput of at least 200 tons/day without causing problems such as a stagnation of molten glass flow in the molten glass flow path, an increment of flow rate of the molten glass flow in a local area, an excessive increment of pressure loss of the molten glass flow. A vacuum degassing apparatus comprises a vacuum degassing vessel, and an uprising pipe and a downfalling pipe which are connected with the vacuum degassing vessel, wherein the vacuum degassing vessel includes a wide portion for providing a molten glass flow path, and in the wide portion, the proportion W1/L1 of the breadth of molten glass flow path W1 to the length of molten glass flow path L1 is at least 0.

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 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: A system and method are described herein that control the environment (e.g., oxygen, hydrogen, humidity, temperature, gas flow rate, pressure) around one or more vessels in a glass manufacturing system. In the preferred embodiment, the system includes a closed-loop control system and a capsule that are used to control the level of hydrogen around the exterior (non glass contact surface) of the vessel(s) so as to suppress the formation of gaseous inclusions and surface blisters in glass sheets. In addition, the closed-loop control system and capsule can be used to help cool molten glass while the molten glass travels from one vessel to another vessel in the glass manufacturing system. Moreover, the closed-loop control system and capsule can be used to maintain an atmosphere with minimal oxygen around the vessel(s) so as to reduce the oxidation of precious metals on the vessel(s).

Abstract: A system and method are described herein that control the environment (e.g., oxygen, hydrogen, humidity, temperature, gas flow rate, pressure) around one or more vessels in a glass manufacturing system. In the preferred embodiment, the system includes a closed-loop control system and a capsule that are used to control the level of hydrogen around the exterior (non glass contact surface) of the vessel(s) so as to suppress the formation of gaseous inclusions and surface blisters in glass sheets. In addition, the closed-loop control system and capsule can be used to help cool molten glass while the molten glass travels from one vessel to another vessel in the glass manufacturing system. Moreover, the closed-loop control system and capsule can be used to maintain an atmosphere with minimal oxygen around the vessel(s) so as to reduce the oxidation of precious metals on the vessel(s).

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 substantially-isolated/controlled, limited-volume, gas-filled space (e.g., 113b) is formed over at least one free (open) surface of flowing molten glass in a manufacturing line used to produce glass sheets (137), e.g., a manufacturing line employing the fusion process to produce glass sheets suitable for use as substrates for liquid crystal displays. At least a portion of the space comprises a platinum-group metal, e.g., a platinum-rhodium alloy, which can serve as a source of platinum-group condensate defects. The use of the substantially-isolated/controlled, limited-volume, gas-filled space substantially reduces the level of such platinum-group condensate defects in the glass sheets, e.g., by more than 50%.

Abstract: A conduit structure for molten glass, a conduit system for molten glass, a vacuum degassing apparatus and a method for vacuum-degassing molten glass by use of the vacuum degassing apparatus, which are capable of effectively removing components eluted from a refractory brick forming a conduit for molten glass, foreign substances generated in the interface between molten glass and a platinum wall surface forming a conduit for molten glass, a bubble remaining in a surface layer of molten glass, a glass material denatured by volatilization, and the like, are provided.

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: To provide a glass production process capable of reducing bubbles remaining in glass after production, substantially without a refiner. A glass production process, characterized in that glass to be produced is soda lime glass containing water, and the process comprises a step of subjecting molten glass to reduced pressure defoaming in an atmosphere under a pressure of at most the bubble growth starting pressure Peq (kPa) represented by the following formula (1): Peq=?80.8+98.2×[?-OH]+68.0×[SO3]+0.0617×T??(1) wherein [?-OH] is the ?-OH value (mm?1) of glass, [SO3] is the content (as represented by mass percentage based on oxides) of SO3 in glass, and T is the temperature (° C.) of the molten glass.

Abstract: The invention relates to a device capable of rotating about an axis (6), for the refining and homogenization of glass, comprising a receptacle (1) intended to receive the molten glass to be treated, a vacuum compartment (2) and at least one glass outlet orifice (5, 19), furthermore including a conveying means (7, 8, 17, 18) for conveying the molten glass from the feed receptacle (1) to the vacuum compartment (2). It also relates to a process for manufacturing substrates employing the device according to the invention, and to the substrates thus manufactured.

Abstract: A backup structure for hollow tube made of platinum or a platinum alloy in which glass exudation from bricks employed for the backup is prevented, is provided and a vacuum degassing apparatus and a glass producing apparatus employing such a backup structure are provided. A backup structure for hollow tube made of platinum or platinum alloy, which is used in a high-temperature environment, which contains a fused cast refractory layer provided along an outer surface of the hollow tube made of platinum or a platinum alloy, wherein at least in a portion of the fused cast refractory layer in contact with the outer surface of the hollow tube, the component ratio of fused cast refractories containing at most 10 mass % of matrix glass phase, is at least 50 vol %.

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 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 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.

Abstract: A method for controlling the foam produced when a molten material encounters reduced pressure in a vacuum chamber includes passing the molten material through an aging zone in the vacuum chamber in which the molten material is allowed to drain from between the bubbles of the foam and then collapsing the bubbles of the drained foam.

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: A process for producing a glass for cathode ray tubes, having a Sb2O3 content of from 0 to 0.19% as represented by mass percentage and containing H2O, which process comprises a step of melting a raw material in an atmosphere under a pressure of P0 to obtain a molten glass, and a step of vacuum degassing the molten glass in an atmosphere under a pressure PA which is lower than P0, wherein the pressure P of the molten glass is made to be at most (6.1 W+0.06) atm in the vacuum degassing step, wherein W is the content of said H2O as represented by mass percentage.

Abstract: A vacuum degassing apparatus for molten glass includes a vacuum housing; a vacuum degassing vessel provided in the vacuum housing; an uprising pipe which connects to the vacuum degassing vessel; and a downfalling pipe which connects to the vacuum degassing vessel. The vacuum housing has an accommodating portion to accommodate the uprising pipe and an accommodating portion to accommodate the downfalling pipe, at least one of which is divided horizontally into a plurality of sections to form a plurality of divided rooms juxtaposed in the vertical direction, and the respective divided rooms are provided with a pressure controller to control the pressures of the respective divided rooms independently.

Abstract: Systems and methods for large scale synthesis of germanium selenide glass and germanium selenide glass compounds are provided. Up to about 750 grams of a germanium selenide glass or a glass compound can be synthesized at a time in about eight hours or less. Stoichiometrically proportional amounts of germanium and selenium are placed in an ampoule. A variable may also be placed in the ampoule. The ampoule is heated to above the softening temperature of the glass or glass compound being synthesized. The ampoule is then rocked for a period of time while the temperature is held constant. The temperature of the ampoule is then brought down to above the softening temperature of the glass or glass compound being synthesized and then quenched.

Abstract: A method for controlling the foam produced when a molten material encounters reduced pressure in a vacuum chamber includes passing the molten material through an aging zone in the vacuum chamber in which the molten material is allowed to drain from between the bubbles of the foam and then collapsing the bubbles of the drained foam.