Abstract: A melt tank for the production of a glass melt having a low portion of bubbles. The melt tank includes an inlet opening, an outlet opening, a floor, at least two side walls that adjoin the floor, a roof. The glass melt having a first bath depth in a melting segment, a second bath depth in a refining segment, and a third bath depth over a threshold between and smaller than the first and second bath depths. An electrically produced first heat energy is supplied via a multiplicity of electrodes that extend into the glass melt and a second heat energy is produced by the combustion of fossil fuel via at least one burner. Also, a method for producing a glass melt.

Abstract: 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.

Abstract: A method comprises flowing an oxidant and a fuel into a submerged combustion burner in a glass tank furnace, the glass tank furnace receiving a feed of glass forming material and producing molten glass, the burner and furnace comprising a melting system. The melting system has a variable system vibration and/or oscillation due to the nature of submerged combustion. One method includes predicting a value of at least one property, such as viscosity, of the molten glass using the variable system vibration and/or oscillation.

Abstract: A glass-melting furnace, which suppresses the effect of exhaust gas on molten glass quality, a process for producing molten glass, and a process and apparatus for producing glass products. The glass-melting furnace containing: a raw glass material particle feed portion disposed downwardly at a furnace wall portion in an upper portion of the glass-melting furnace; a heating unit provided under the feed portion, which forms a gas phase portion for converting raw glass material particles into liquid glass particles; a flue inlet disposed on the upstream side of the gas phase portion in a flow direction of the molten glass liquid; a furnace-bottom portion, which accumulates the liquid glass particles that produce the molten glass liquid; and a discharge portion, which discharges the molten glass liquid.

Abstract: A glass-melting furnace (10) has an upstream end (6), a downstream end (8), and a roof (22). The upstream end is positioned upstream of the downstream end. A charger (32) is provided to supply glass-forming material (30) to the upstream end of the furnace. At least one burner (34) is provided to supply heat to the glass-forming material at the upstream end of the furnace. An exhaust (60) is in communication with the downstream end of the furnace, with the exhaust being positioned downstream of the at least one burner.

Abstract: During the heating of glass melting furnaces having a combustion chamber with regenerators for preheating oxidation gases, with port necks that open into the combustion chamber, with primary burners and with secondary burners that are installed in a cascade arrangement relative to the primary burners, the secondary burners are operated as cascade burners with a relatively low proportion of the fuel, the secondary fuel. Flames are thereby created in over- and sub-stoichiometric conditions and the flame gases formed are mixed with one another so that the complete combustion process in the combustion chamber is more or less stoichiometric. The secondary fuel is supplied by the secondary burners to a step, installed in the port neck.

Abstract: A method of producing flat glass in which foam which appears on the surface of molten glass melted using oxy-fuel burners is dispersed by directing a diffuse, luminescent flame onto the surface of the glass carrying the foam.

Abstract: According to the invention, measures will be taken to lead the current of the molten glass through the tank furnace so that cutoffs of the glass current between the surface of the glass bath, on the one hand, and the outlet opening on the other hand are avoided and a an equal holding period of all melt particles in the tank furnace is achieved.

Abstract: During the heating of glass melting furnaces having a combustion chamber with regenerators for preheating oxidation gases, with port necks that open into the combustion chamber, with primary burners and with secondary burners that are installed in a cascade arrangement relative to the primary burners, the secondary burners are operated as cascade burners with a relatively low proportion of the fuel, the secondary fuel. Flames are thereby created in over- and sub-stoichiometric conditions and the flame gases formed are mixed with one another so that the complete combustion process in the combustion chamber is more or less stoichiometric. The secondary fuel is supplied by the secondary burners to a step, installed in the port neck.

Abstract: A process for melting and refining vitrifiable materials. In this method all or part of the thermal energy necessary for melting the vitrifiable materials is supplied by the combustion of fossil fuel with at least one oxidizer gas, the fuel, gas or the gaseous products resulting from their combustion are injected below the level of the mass of the vitrifiable materials. The refining of the vitrifiable materials after melting includes at least the step of subjecting them to subatmospheric pressure.

Abstract: This apparatus is a furnace for heating molten material which employs oxygen-fuel burner assemblies. Preferably, the assemblies are submerged in the molten material. They are water cooled top down units with burner nozzles being off-set from the supply column. The apparatus utilizes one or more burners for each top down supply column. The supply column and attached burners can be rotated or moved in a manner to avoid the open chimney effect seen with fixed air-fuel burners of the prior art. These burners with an off-set nozzle like the letter L are rotated at high speed or oscillated to distribute the combustion in the form of gas bubbles or a gas curtain. In another embodiment, the oxy-fuel burners are not submerged. The nozzles are aimed at unmelted batch or the upper surface of the molten material for controlled splashing.

Abstract: A system for melting and delivering glass to a work area such as spinners for making fiberglass includes a melter with heaters so arranged that the “hot spot” in the molten glass is located away from the walls and corrosion sensitive parts so that the various elements of the melter wear out at substantially the same time. The system is further provided with a dual exhaust arrangement when the melter, conditioner and forehearth are located on the same floor of the plant, the first exhaust being at the juncture of the melter and conditioner, and the second being an alternating replacement for one of the heating/cooling orifices and mechanisms in the conditioner, so as to effectively limit the amount of corrosive volatiles reaching the forehearth.

Abstract: A forehearth (20) for cooling glass from a melting furnace as it flows to a feeder bowl (28) from which it is discharged to a forming machine. The forehearth is in the form of an elongate, horizontally extending insulated trough (26) with a roof formed by a longitudinally extending series of roof block elements (30), each of which is of one-piece construction and extends completely across the width of the insulated trough. The downwardly facing surface of each roof block element is contoured to incorporate concave portions (30a, 30b) near the edges of the forehearth, a concave portion (30c) above the center of the forehearth and convex portions (30d, 30e) separating the center concave portion from the side concave portions to substantially impede heat transfer between the side concave portions and the center concave portion.

Abstract: Nanocrystalline glass-ceramic materials based on .beta.-quartz solid solution Mg-rich phases formed in the system SiO.sub.2 --Al.sub.2 O.sub.3 --MgO--Li.sub.2 O--TiO.sub.2 (ZnO, BaO, ZrO.sub.2, P.sub.2 O.sub.5). Articles made from the glass-ceramic materials exhibit a crystal phase assemblage of a fine-grained, microstructure which is predominantly .beta.-quartz, and at least one additional phase selected from enstatite and spinel, and having a composition which consists essentially of, in weight percent on the oxide basis, 40-65% SiO.sub.2, 10-14% Al.sub.2 O.sub.3, 5-25% MgO, 0.5-4% Li.sub.2 O, 5-15% TiO.sub.2, and up to 5% ZrO.sub.2, such that the sum of (TiO.sub.2 +ZrO.sub.2) is at least 9% The glass-ceramide article is particularly useful for memory disk applications.

Abstract: In order to provide a crystallized glass which can be shaped by the redraw forming and a method of manufacturing a crystallized glass article by the redraw forming, the crystallized glass contains precipitated crystals with a maximum grain size not greater than 5 .mu.m and a glass phase at a ratio of 10 to 85 vol %, and has a softening point lower than a melting point of a predominant precipitated crystal, and a property such that crystallization does not progress even when heated at a temperature higher than the softening point. In order to manufacture the crystallized glass article formed by the redrawing, the above-described crystallized glass is preformed and then subjected to the drawing while being heated to a temperature higher than the softening point.

Abstract: A system for melting and delivering glass to a work area such as spinners for making fiberglass includes a melter with heaters so arranged that the "hot spot" in the molten glass is located away from the walls and corrosion sensitive parts so that the various elements of the melter wear out at substantially the same time. The system is further provided with a dual exhaust arrangement when the melter, conditioner and forehearth are located on the same floor of the plant, the first exhaust being at the juncture of the melter and conditioner, and the second being an alternating replacement for one of the heating/cooling orifices and mechanisms in the conditioner, so as to effectively limit the amount of corrosive volatiles reaching the forehearth.

Abstract: Composite material comprising a CAS+BAS vitroceramic matrix reinforced with SiC fibers and exhibiting a small difference between the thermal expansion coefficients of the matrix and the fibers is obtained by using a matrix having a BaO/(BaO+CaO) molar ratio of between 25% and 55% and predominant phases of triclinic anorthite and monoclinic celsian.

Abstract: A composite for a dental restoration is presented comprising ground, densified, embrittled glass fibers together with fillers and a polymeric matrix precursor composition. The ground, densified, embrittled glass fibers are obtained by grinding glass fibers which have been densified and embrittled by heating glass fibers at a temperature substantially below the softening point of the glass fibers, without significant fusion or melting together of the fibers. The composite is particularly useful as a direct filling material, in that it has the feel and workability of an amalgam.

Abstract: A low temperature firing glass-ceramic substrate comprising a borosilicate glass, .alpha.-alumina, .gamma.-alumina, and mullite crystals crystallized out in a dispersed form from the borosilicate glass and the .gamma.-alumina, and a production process of the substrate. It is an object of this invention to provide a glass-ceramic substrate, which is low in dielectric constant and dielectric loss and high in strength and is useful for multilayer wiring.

Abstract: A method for improving the energy efficiency of oxygen-fired glass melting furnaces wherein heat from hot flue gases from the melting furnace is used to heat all or part of the combustion oxidant and thereafter to preheat at least a portion of the glass forming materials to be melted.

Abstract: A mixing method insures adequate mixing of gases in a glass furnace that employs a reburning process. Because of the mixing method, a novel glass furnace can be constructed that strikes an optimum balance between a reduction in nitrogen oxide (NO.sub.x) emissions and the cost of the reburn process, particularly, the number of requisite reburn and overfire air jets as well as reburn fuel. The glass furnace is constructed as follows. A combustion housing defines a primary zone for receiving combustible fuel, a reburn zone connected to the primary zone for receiving exhaust from the primary zone and reburn fuel to generate a first gas mixture. A burnout zone is connected to the reburn zone and receives the first gas mixture and overfire air to generate a second gas mixture.

Abstract: A method of operating a regenerative glass melting furnace with end-firing or cross-firing utilizes burners to provide sub-stoichiometric combustion and super-stoichiometric combustion along the sidewalls or transverse walls of the furnace and equipment associated with the method. Fuel supply is controlled so that overall combustion is stoichiometric.

Abstract: A furnace having a molten material holding tank with sidewall and a tuckstone or other structure above the sidewall upper end leaving a gap, or joint, therebetween. A deflector, or diverter, is provided at the upper end of the sidewall to deflect cooling air directed on the tank sidewall away from the joint and to create a pressure differential between the interior and exterior of the tank thereby reducing air infiltration into the tank through the joint.

Abstract: A tank furnace for the inertization of non-flammable batch, which contains hazardous substances, metals and less than 10% by weight of carbon, by vitrification with glass forming aggregates by producing a glassy melt. The furnace has a batch charging device and a tank, on the rim of which a furnace crown rests, electrodes for heating the melt, a supply of oxidizing gases to the melt and, as an outlet for the melt, an overflow channel which can be heated. Nozzles are installed in the bottom of the tank to introduce oxidizing gases in order to reduce the eluate values, and the electrodes are immersed in the melt from above. It is preferable to install the nozzles at sloping sidewalls of the tank which slope upwardly and outwardly.

Abstract: Described is a process for the manufacture of glass substrates with improved long-term stability at raised temperatures, in which process a glass substrate is provided with a coating, this coating being prepared from a composition, which was obtained through hydrolysis and condensation of a compound that was dissolved in a solvent and belonged to at least one element from the group Si, Al, Ti and Zr and/or a suitable precondensate, optionally in combination with compounds, which are soluble in the reaction medium, of at least one element from the group of alkali metals, alkali earth metals, and boron. After the coating composition is deposited, the coating obtained thus is heat treated. The process is characterized in that the coating is not completely compacted.

Abstract: A leucite-containing phosphosilicate glass-ceramic is described which, in addition to a leucite crystalline phase and at least one further crystalline phase, also contains one or more glass phases.

Abstract: A Si.sub.3 N.sub.4 reinforced aluminosilicate ceramic composite made ofA. from about 5 to about 40 weight percent of Si.sub.3 N.sub.4 reinforcem material;B. from about 15 to about 35 weight percent of the recrystalization products formed from a molten glass composed of(1) from about 8 to about 16 weight percent of Al.sub.2 O.sub.3,(2) from about 14 to about 45 mole percent of an alkaline earth oxide selected form the group consisting of BaO, SrO, and mixtures thereof, and(3) SiO.sub.2 being the remainder of the molten glass,wherein the recrystallization products are formed from the molten glass when the ceramic composite is cooled down after firing;C. the remainder of the composite being monoclinic BaO.Al.sub.2 O.sub.3.2SiO.sub.2 (BAS), monoclinic SrO.Al.sub.2 O.sub.3.2SiO.sub.2 (SAS), or a monoclinic solid solution of BAS and SAS.

Abstract: The present invention relates to a process for forming glass-ceramic tiles. Spent aluminum potliner containing carbonaceous material, fluorine, and glass forming materials is oxidized under conditions effective to combust the carbonaceous material and volatilize partially the fluorine in the glass forming materials. The oxidized glass forming materials are vitrified to form a glass melt. This glass melt is then formed into tiles containing fluorine.

Abstract: A cordierite glass-ceramic having a cordierite crystal phase as a predominant crystal phase is obtained by melting a base glass consisting in weight percent of:______________________________________ SiO.sub.2 38-50% Al.sub.2 O.sub.3 18-30% MgO 10-20% ______________________________________the ratio in weight of Al.sub.2 O.sub.3 to MgO being 1.2 to 2.3 ______________________________________ B.sub.2 O.sub.3 0-5% CaO 0-5% BaO 0-5% SrO 0-5% ZnO 0.5-7.5% TiO.sub.2 4-15% ZrO.sub.2 0-5% As.sub.2 O.sub.3 + Sb.sub.2 O.sub.3 0-2% ______________________________________and forming the glass and subjecting the glass to heat treatment. This glass-ceramic is suitable for use as a high strength material reqiring high resistivity to heat and impact and as materials requiring a fine processing or a precision processing such as electronic parts, magnetic disk substrates and machine parts.

Abstract: Conductive via fill inks for green tapes to be stacked and bonded to a support substrate, the glass used for the green tape having a firing temperature from 850.degree.-950.degree. C., wherein the glass used for the via fill ink has a glass transition temperature that is higher than that of the glass used to make the green tape, preferably does not crystallize at the maximum firing temperature of the green tape and comprises from 30-75 percent by volume of the glass-conductive metal powder mixture of the via fill ink. These conductive via fill inks will not shrink until the green tape shrinkage has commenced during firing of the composite circuit board and they will flow slightly during firing, forming good bonds to the glass in the walls of the vias, thereby ensuring good integrity of the vias and good connections to the circuitry on the fired ceramic multilayer circuit board.

Abstract: A forehearth for a glass furnace comprises a trough and roof over the trough, the roof having two longitudinal ridges extending downwardly towards the surface of the glass to define three longitudinal chambers. The central chamber forms a conduit for the flow of cooling air over the central part of the stream of glass and the side chambers serve as conduits for the flow of combustion gas. Separate outlets are provided for the cooling and combustion gases and controllable dampers are provided at least on the combustion gas outlets. Balancing of the internal pressures between the three chambers can ensure that there is little or no significant mixing of the cooling air and combustion gases and accurate control of the cooling and/or heating can be obtained by control of the dampers.

Abstract: A forehearth for the conveyance and temperature maintenance of molten glass includes a longitudinal cooling zone over a laterally-extending cooling tile panel which is spaced above and spans an elongated trough supporting the molten glass. Roof structure of the forehearth has a pair of spaced-apart projections jutting downwardly and defining a central cooling area over the molten glass, and the central cooling area is flanked by longitudinally-extending firing chambers. Linear parallel grooves, recessed within at least one broad surface of the cooling tile panel, increase the rate of heat transfer to a longitudinally-extending air flow cavity above the cooling tile panel. The cavity has spaced air inlets along its sides that communicate with the parallel grooves of the panel and direct pressurized cooling air in laterally converging paths through the grooves and thence outwardly through a centrally located exhaust opening.

Abstract: The invention relates to a process for melting glass forming ingredients in a glass melting furnace adapted therefore, said furnace having an upstream melting zone and a downstream fining zone, wherein the glass forming ingredients introduced to the upstream melting zone via inlet means and the resulting melt therefrom travel along a path from the melting zone to the fining zone, said melt being withdrawn from outlet means which communicate with the fining zone, the improvement comprising; providing at least one high momentum oxygen-fired flame in the vicinity of said outlet means to sweep unmelted glass forming ingredients floating on the surface of the melt in said vicinity to prevent said unmelted glass forming ingredients from entering the outlet means whereby the contamination of an outflowing molten glass from said outlet means is avoided or reduced.

Abstract: A plurality of conduit segments contact on another which run vertically and transversely to the direction in which molten glass is channelled. Each segment includes at least one trough section and at least one cover section, an insulation of individual formed bodies, and an external casing. The segments are coupled together on support beams and may have removable insulation at joints to facilitate inspection.

Abstract: A glassmelting method wherein glassforming materials are preheated prior to entering the melting vessel by direct contact with combustion products from the melting vessel produced by combustion carried out with pure oxygen or oxygen-enriched air.

Abstract: Furnace has a melting section and a withdrawal section bounded by side walls of refractory material which extend to a glass outlet formed by an overflow edge remote from the melting section. In operation a molten glass layer, a molten layer of undissolved sulfates, and a batch layer succeed one another from the bottom up in the melting section. The withdrawal section is separated from the melting section by a first dividing wall extending downwardly and terminating above the surface of the molten glass. A second dividing wall is disposed for the formation of an underside glass passage, and at least one closable opening for withdrawing the molten sulfates is disposed at the level of the sulfate layer between the first and second dividing walls. The opening has a bottom boundary whose height is adjustable, so that it can be adjusted to lie above the surface of the glass melt.

Abstract: In a glass melting furnace of the type that has a basin wherein a bath of molten glass is heated by a blanket of flame that extends over the molten bath, performance and productivity are enhanced by installing oxygen injection lances through holes that are drilled through walls of the furnace at tuck stone levels just above the top surface of the molten bath of glass in the furnace basin. The lances are thin walled tubes that each carry an adjustable flange for preventing unwanted convection and radiation through furnace wall holes that receive the lances.

Abstract: The invention relates to working molten glass in tank furnaces for continuous production. According to the process of the invention, the vitrifiable material being brought first to the molten bath state in a zone upstream from the tank, and said bath then having access to the successive downstream zones allocated to the other phases of the process of working the glass through at least one tank portion comprising a section reduction of the type usually called a neck, there is generated at the upper level of the opening available to the glass by said neck a glass current directed from downstream to upstream of said neck. The invention proves to be especially advantageous for electric melting furnaces with large production capacity.

Abstract: A conduit for conducting molten glass in a glass making operation comprising an elongate superstructure, an elongate carriage, a plurality of refractory blocks assembled on the carriage to form a channel for conducting molten glass, and a plurality of rollers for supporting the carriage in the superstructure and allowing the carriage to be slid out of the superstructure for servicing. The conduit further comprises clamping members extending along the sides of the conduit roof, and support members on the superstructure which can be operated transversely inwardly to cause the clamping member to engage and support the roof so that the carriage can be removed from the superstructure independently of the roof.

Abstract: A forehearth for transport of molten glass, characterized in that cooling surfaces of a material having a high heat conductivity, particularly a metallic material, are disposed in the roof of the forehearth. The metallic material may be an iron-chromium-aluminum alloy having fifteen to thirty percent by weight of chromium, three to twelve percent by weight of aluminum, and a balance of essentially iron.

Abstract: In a method of making glass or the like, wherein the batch materials are liquefied in a distinct zone from the refiner, the liquefied material is heated in an intermediate stage before being fed to the refiner, and a composite barrier of a cooled frame with graphite inserts is employed to restrict passage of material from the intermediate stage.

Abstract: In a method of making glass or the like, wherein the batch materials are liquefied in a distinct zone from the refiner, the liquefied material is heated in an intermediate stage before being fed to the refiner. In preferred embodiments the intermediate stage comprises one or more channels extending from the side of the refiner.

Abstract: A lid of a glass batch melting vessel is subjected to corrosive and thermal degradation. The lid is cooled and the temperature of the exploded inner surface of the lid is controlled such that particulate and molten materials entrained in exhaust gas circulating within the vessel adhere to the lid surface forming a protective, insulating coating that prolongs the service life of the lid.

Abstract: Foaming of molten glass or the like as it enters a vacuum refining vessel is enhanced by altering the incoming stream so as to increase its surface area and/or retarding the passage of the stream through the vacuum headspace so as to increase its exposure to the vacuum.

Abstract: A melt of a material such as glass is inductively heated at a stage intermediate an initial liquefying stage and a refining stage. The function of the intermediate induction heating stage is essentially limited to raising the temperature of the melt a relatively minor amount to a refining temperature. Therefore, the induction heating stage may be compact with an intensified heating rate and rapid throughput, thereby permitting the induction heating zone to be a "cold" walled vessel without an appreciable effect on efficiency.

Abstract: A furnace for cooling molten glass, which comprises a cooling tank for slowly cooling the molten glass while the average temperature of the molten glass is within a certain range extending below and above the temperature at which the speed of absorbing bubbles is highest, and cooling it rapidly when the average temperature of the molten glass is outside said range.

Abstract: An alcove for conducting molten glass to a plurality of forehearths for delivery to glassware forming equipment, comprising a series of zones with a trough extending through the zones and a barrel vault roof over the trough in each zone, the vault bearing on blocks at the top of the sides of the trough carrying burners, the vault having keystones formed to provide side channels over side portions of the stream of molten glass in the trough and a central channel over the central portion of the stream.

Abstract: A method and apparatus for continuously melting and refining molten glass are disclosed which comprises the steps of applying a preponderance of heat to a molten glass mass by Joule effect heating and pulsating a portion of the heat applied to the molten glass mass such that the temperature of the surface molten glass is increased and the temperature of the molten glass being withdrawn is reduced and the total energy supplied to the furnace is reduced. An electric circuit means comprising at least two interconnected electrodes is pulsated on and off at predetermined time intervals in order to establish the desired temperature profile within the molten glass mass.

Abstract: The device comprises a three-dimensional grid of thermocouples which are immersed in a fluid, which is moving in a covered channel and has a temperature above that of its environment. Apertures in the sheathing of the channel can be progressively closed by shutters so as to control the cooling of the fluid through an outgoing radiation through the apertures. Burners with a variable intensity are placed within the channel and allow to heat up the fluid in the vicinity of each burner. The position of each shutter and the fuel flow to each burner are commanded severally, based on the values emitted by the ensemable of the thermocouples in order to obtain a homogeneous repartition of the temperature of the fluid, transversally with respect to the channel.

Abstract: A glass melting furnace and process wherein a second combustion zone toward the glass discharge end of the glass melting chamber is underport sideport fired while a first combustion zone toward the batch charge end of the glass melting chamber is side-of-port and/or overport sideport fired.