Abstract: A mixing apparatus which prevents erosion of left and right side walls 12a 12b for a flow path 12 for a molten substance of high temperature M and homogenizes the molten substance of high temperature while occurrence of air bubbles is prevented, wherein there are a plurality of mixing units 11 in the flow path 12; an even number of pairs of mixing units 11 are arranged symmetrically with respect to the center line in a longitudinal direction of the flow path 12 and the gap s between a left side wall or a right side wall and an outer peripheral edge of a mixing blade 14 is determined to be 0.04-0.1 times as much as the distance W between the left and right side walls 12a, 12b.

Abstract: A bushing including a tip plate having an orifice region including orifices to permit flow of a molten fiberizable material therethrough; a reservoir for supplying molten fiberizable material to the orifices; and a substantially planar perforated plate positioned within the reservoir generally parallel to and substantially coextensive with the orifice region of the tip plate, the perforated plate including a central region and a peripheral region surrounding the central region, each of the central region and the peripheral region of the perforated plate having a plurality of openings to permit flow of molten fiberizable material therethrough, wherein average head loss of molten material flowing through the central region of the perforated plate is greater than average head loss of molten material flowing through the peripheral region of the perforated plate.

Abstract: A molten glass recirculating apparatus is provided, comprising a riser chamber having a first opening positioned below a molten glass level and a second opening positioned above a molten glass level, a trough positioned adjacent the upper opening, and a gas emitter positioned within the riser chamber below a molten glass level and methods of using the same. When a gas is emitted from the gas emitter, molten glass contained within the riser chamber rises and exits the riser chamber through the second opening and along the trough. The exiting molten glass causes additional molten glass to be drawn into the riser chamber through the first opening. The invention also comprises a glass melter including a plurality of glass recirculating means, each being individually controllable to control the circulation of molten glass within a glass melter.

Abstract: A refining method for molten glass comprising a stirring step for stirring molten glass in a stirring vessel, a feeding step for feeding the molten glass into a vacuum vessel via an uprising pipe, a degassing step wherein the molten glass is put under a reduced pressure in the vacuum vessel, bubbles produced on the molten glass surface and a flow of the molten glass just below the molten glass surface are blocked by a barrier provided in the vacuum vessel, and the molten glass is degassed in a state that a bubble layer is formed on the molten glass surface, and a discharging step for discharging the molten glass after degassing from the vacuum vessel through a downfalling pipe to a storage vessel.

Abstract: A method and apparatus for making float glass, wherein the glass is stirred in the conditioning zone adjacent the entrance to the float canal so as to attenuate the glass across the entire width of the float canal.

Abstract: A furnace (1) for melting vitrifiable materials, including a compartment (2) for melting and refining the glass equipped, upstream, with at least one means (4) for charging vitrifiable-materials and leading, downstream, into a compartment or a series or compartments (6-7-8) intended to lead the molten glass as far as the forming zone. It is equipped with a first means for controlling the convective flows of the mass of molten glass in the form of a transverse sill (14) delimiting an "upstream" zone (3) and a "downstream" zone (5). Associated with this sill are complementary means for controlling the convective flows in the "upstream" zone including, as a minimum, submerged "upstream" heating means (15) located close to and upstream of the sill, in order to prevent molten glass that has reached said the "downstream" zone from returning into the said "upstream" zone.Another subject of the invention is the application of such a furnace and the method of operating it.

Abstract: At least one cooling zone and a subsequent homogenization zone are installed between the inlet and the outlet of a forehearth for conditioning and homogenizing a stream of colored glass. The glass temperature in the forehearth is reduced from the inlet temperature T1 to an outlet temperature T2. In order to increase the cooling effect while simultaneously homogenizing the glass temperature at a throughput of at least 70 tons per day, a raised area is installed in the bottom along the length of the cooling zones to set a maximum bath depth Dmax of 120 mm. Furthermore, the cooling capacity is such that the temperature 20 mm above the bottom is reduced by at least 40.degree. C. in the cooling zone. In the apparatus used, the raised area above the bottom covers the complete length of the cooling zones K. The maximum depth Dmax of the glass bath is 120 mm above the raised area and in the homogenization zone the channel is at least 30 mm deeper.

Abstract: A continuously flowing glass stream is conditioned and homogenized along a conditioning stretch, which extends from an entry side to at least one extraction point, and at the beginning of which there is a cooling zone, to which at least one homogenizing zone for the glass temperature is connected. In the working end or the distribution channel the temperature is reduced from the entry temperature T1 to an outlet temperature T2. In order to achieve the necessary conditioning and homogenization, even at high throughputs, the glass stream in the at least one cooling zone of the working end or distribution channel has a cross section with a depth/width ratio D/W of a maximum 0.6, or 0.5, or 0.4, or 0.3 or 0.

Abstract: A method and apparatus for the production of colored glass includes the steps of diverting a stream of clear molten glass from at least one glass melting furnace through one or more transport channels to a color treatment chamber. Recycled cullet and color additive are added to a charging end of the treatment chamber. The treatment chamber is heated to melt the cullet and further heat the remaining feedstock to form a molten bath of colored glass which is thermally and chemically homogenized in the treatment chamber. Refractory rotary paddle wheels positioned in the transport channels regulate the flow rate and level of the molten glass and provide for selective shut off of individual glass streams.

Abstract: In a furnace for melting glass, a preheating zone, a melting zone, a refining zone with a refining bank raised above the rest of the floor and an homogenizing zone, are arranged lengthwise behind one another between the charging end for the glass raw materials and a throat for the molten glass. The furnace chamber formed between two end walls is split up by dividing walls with the exception of flow paths for the glass and waste gases. The melting zone, the refining zone, several burners and the homogenizing zone have a common combustion chamber in the superstructure. A first flow path "L1" for the glass is defined between the inside face of the first end wall and the vertical center line (E) of the final dividing wall in front of the refining zone, and a second flow path "L2" is defined in the combustion chamber between the vertical center line (E) and the inside face of the second end wall. The ratio of the length "L2" to the total length ("L1"+"L2") is chosen to be at least 0.5, preferably at least 0.53.

Abstract: A flow duct or throat 1 for the passage of molten glass from the glass production zone to the shaping zone incorporates glass homogenizing stirrers 15, 16, 17 and 18, as well as a flow channel 2 and a heel 40. The stirrers, flow channel and heel are effective for avoiding the formation of a glass back flow.

Abstract: A glass melter 30 having a mixing impeller 34 for converting a feed stream 38 supplied to a vessel 32 into a vitrified glass melt 50. Heating means such as electrodes 36 or a gas burner 58 are used to heat the glass melt 50. Electrode 36 arrangements are proposed for minimizing current flow through the impeller 34. Current flow through a special continuous circular impeller or conical pump 70 is disclosed. A cylindrical vessel 98, triangular vessel 94, square vessel 32, and hexagonal vessel 96 are disclosed. Methods of processing particular waste streams are disclosed including coated mineral fibers, fly ash, radioactive material, chemical waste and the like.

Abstract: A glass melter 30 having a mixing impeller 34 for converting a feed stream 38 supplied to a vessel 32 into a vitrified glass melt 50. Heating means such as electrodes 36 or a gas burner 58 are used to heat the glass melt 50. Electrode 36 arrangements are proposed for minimizing current flow through the impeller 34. Current flow through a special continuous circular impeller or conical pump 70 is disclosed. A cylindrical vessel 98, triangular vessel 94, square vessel 32, and hexagonal vessel 96 are disclosed. Methods of processing particular waste streams are disclosed including coated mineral fibers, fly ash, radioactive material, chemical waste and the like.

Abstract: An instrument and system for the preparation of a sample for analysis provides a crucible holder which improves the holding and control of a melting crucible during operation of the device for agitating a powdered sample and flux while being heated. The crucible holder is coupled to an agitation assembly which provides independently controlled operation on two different axes using separately adjustable variable frequency and amplitude motion along each of the two operating axes to provide an finite number of agitation patterns for the crucible. In one preferred embodiment of the invention, the heating flame is controlled by controlling the supply of compressed air and a combustion gas. In another preferred embodiment of the invention, a pilot burner is provided which both ignites the main burner located under the crucible and preheats the casting dish to a temperature which is substantially the same as the crucible.

Abstract: A furnace has side walls and a bottom wall with a refractory lining. To permit mounting of ancillary equipment such as electrode refractory blocks are fitted to the bottom wall of the furnace. To mount each refractory block a hole is bored through the bottom wall from the exterior of the furnace with a large diameter in the outer part of the wall and a smaller diameter in the lining. The refractory block has a stepped construction to fit closely inside the bored holes. A central passageway through the refractory block has a removable plug at its inner end which may be displaced by insertion of an ancillary device such as an electrode.

Abstract: Material, such as, for example, sealed double bags of asbestos containing waste or ash from infectious waste or toxic material or radioactive waste, is transferred into a glass melt of a furnace. Gas bubbles released into the melt form a gas curtain which causes enhanced mixing of the material to accelerate the dissolution of the components of the added material. The presence of the gas bubbles reduces the cross-section of the molten glass through which current passes, which in turn increases the electrical resistance of the glass melt and therefore increases power generation of the melt or power density at constant current. A highly oxidizing hot region is produced under the location where the material is introduced into the furnace. Drawn off glass is shaped and quenched into at least two sizes of approximate spheres. The spheres are cooled sufficiently fast to be thermally tempered and have a surface compressive strength level above 5000 psi.

Abstract: A glass melter 30 having a mixing impeller 34 for converting a feed stream 38 supplied to a vessel 32 into a vitrified glass melt 50. Heating means such as electrodes 36 or a gas burner 58 are used to heat the glass melt 50. Electrode 36 arrangements are proposed for minimizing current flow through the impeller 34. Current flow through a special continuous circular impeller or conical pump 70 is disclosed. A cylindrical vessel 98, triangular vessel 94, square vessel 32, and hexagonal vessel 96 are disclosed. Methods of processing particular waste streams are disclosed including coated mineral fibers, fly ash, radioactive material, chemical waste and the like.

Abstract: A method and apparatus for recycling scrap mineral fibers (42) having an organic binder coating in a highly stirred glass melter (16) wherein the organic binder coating is decomposed by applying heat. Carbon from the organic binder coating is oxidized on the surface of the glass melt (17). After oxidizing the carbon, the glass fibers are dispersed into the melt. Residual carbon may be oxidized after inclusion in the melt. Purified glass suitable for forming glass fibers is further processed by conventional glass fiber forming equipment. The method may also include the step of pre-processing the glass fiber scrap by shredding or pulverizing to facilitate feeding the glass fiber scrap to the highly stirred glass melt. The apparatus according to the present invention is preferably a stirred melter (16) having electrical joule effect heating. An impeller (22) in the glass melt stirs the melt at a high rate of speed to provide a draw down effect pulling fibers into melt.

Abstract: Better homogenization of molten glass or the like is achieved by a row of stirrers when greater stirring force is provided in the center portion of the row. Preferred embodiments employ stirrers with blades, and stirrers in the center portion have longer blades than in outboard portions of the row.

Abstract: In a method of and an apparatus for melting glass having high reducing activity when melted, a glass raw material charged into a melting vessel having a wall formed of platinum or alloy thereof is heated and melted. Oxygen gas is supplied to an outer surface of the melting vessel to raise oxygen partial pressure within an atmosphere surrounding the melting vessel. The oxygen gas is caused to penetrate through the wall of the melting vessel, thereby supplying the penentrated oxygen to a layer of the molten glass which is in contact with an inner surface of the wall of the melting vessel, so that the layer of the molten glass is formed into a protective glass layer rich in oxygen, for protecting the wall of the melting vessel from the molten glass.

Abstract: The device pursuant to the invention comprises means for agitation composed of at least one horizontal agitator formed from a series of essentially vertical loops extending over the entire width of the bath near the collar between the refining zone and the homogenization zone, with the horizontal agitator being moved by means that produce an elliptical motion in the horizontal plane.

Abstract: A process for the batchwise production of glass performs melting, refining and discharging steps in electrically heated identical vessels, wherein at least the refining step is conducted during rotation of a vessel, and discharging of the refined glass takes place while the vessel is at rest. By using several vessels, which are either mobile or which are connected with one another by movable spouts, feeding of molten glass to a distributing channel for further processing is done continuously. Vessels according to the invention have electrodes for heating purposes; outlet port sealing arrangements; and ports for applying over-pressure or a vacuum to control glass exit speed. Blast pipes may be disposed in proximity with outlet ports in order to improve flow of the glass melt by introducing blasts of an inert gas.

Abstract: Stirring of glass of high optical quality is effected by initiating forming of the glass, such as by the float process, at relatively high temperatures immediately after the glass has been stirred. Preferably, during and/or following the stirring operation contact between the molten glass and ceramic refractories is minimized. This is preferably accomplished by providing a layer of molton metal (e.g., tin) on the bottom of the stirring chamber.

Abstract: A method and apparatus for heat sealing an electron gun mount, having a glass stem, into a neck of a cathode-ray tube includes a mount socket for supporting the mount within the neck and a plurality of burners for applying heat to the outside of the neck proximate the stem. The neck softens, thins and then seals to the stem, causing excess neck material that is lower than the stem, known as cullet, to be cut off. Prior to applying heat, a sleeve is disposed around the mount socket within the neck adjacent to the cullet, with a clearance between the sleeve and both the socket and the neck. A vibrating coil is attached to the sleeve for vibrating the sleeve while applying heat to the outside of the neck.

Abstract: This invention relates to an apparatus for preparing samples. These samples will be used for making disks and solutions for subsequent analysis by chemical or physical means. The machine contains an assembly of several gas burners with a crucible above each of them for heating and melting the sample-flux mixture. Efficient mixing in the melt is obtained by providing a crucible with a new shape in combination with a periodic tilting or rotation of the crucible. Solutions are prepared by pouring the hot molten glass mixture into beakers containing an acid and by agitating the acid and the glass particles. Glass disks are prepared by placing moulds above the crucibles during heating and by turning the crucibles and the moulds upside down so that the hot molten glass mixture flows into the moulds for subsequent solidification into solid glass disks of high quality, ready for analysis without further processing. Various shapes of crucibles are disclosed.

Abstract: A bubbler assembly comprising a bubbler tube having a sleeve surrounding at least a portion thereof to define an annular space therebetween. A corrosion-inhibiting gas is introduced into the space to minimize oxidation and alkali-sulfate corrosion of the bubbler tube, or preferably the gas is moved through the space to purge the space of oxygen and alkali-sulfate corrosives, when the bubbler assembly is mounted within a mounting hole provided through a refractory wall, e.g. the bottom, of a glassmaking furnace.The bubbler assembly alternatively comprises a bubbler tube, a fluid coolant jacket mounted within the refractory wall mounting hole, and facilities for facilitating movement of the bubbler tube relative to the refractory wall, independently of the fluid coolant jacket.

Abstract: A process and apparatus for improving the removal of gaseous inclusions from molten materials is disclosed. The inclusions, e.g., seeds or bubbles, are removed by applying vibrations to a restricted zone for discharging molten material from the melting tank. The seeds are slowed during a "pile up" in the restricted channel and are more easily brought to the surface of the molten material.

Abstract: In a glass melting furnace, the beneficial effects of passing molten glass streams through the intensified heating at the surface of the "spring zone" are enhanced by the use of bubblers. In one aspect, the rate of bubbling is greater near a side wall of the furnace than in the center immediately upstream of the spring zone so as to direct side portions of the throughput stream into the spring zone. In another aspect of the invention, the rising currents of the spring zone are enhanced by bubbling a stream entering the spring zone at a first elevation and then bubbling the same stream portion at a higher elevation.

Abstract: The invention relates to a method for producing molten glass in a melting furnace 1 equipped with a tank containing a glass bath 3, where the ingredients of the glass are melted in a refining zone 10 and the molten glass flows into an adjacent conditioning zone 13.According to the invention, the current is driven to a passage 31, which is located at the common boundary of the refining zone 10 and the conditioning one 13, this boundary or corset has a narrower width than that of the current, and the current is forced to go through the passage 31.Thus the homogeneity of the glass is increased at drawing off.

Abstract: In a glass melting furnace, the beneficial effects of passing molten glass streams through the intensified heating at the surface of the "spring zone" are enhanced by the use of bubblers. In one aspect, the rate of bubbling is greater near a side wall of the furnace than in the center immediately upstream of the spring zone so as to direct side portions of the throughput stream into the spring zone. In another aspect of the invention, the rising currents of the spring zone are enhanced by bubbling a stream entering the spring zone at a first elevation and then bubbling the same stream portion at a higher elevation.

Abstract: The invention relates to a method for producing molten glass in a melting furnace 1 equipped with a tank containing a glass bath 3, where the ingredients of the glass are melted in a refining zone 10 and the molten glass flows into an adjacent conditioning zone 13.According to the invention, the current is driven to a passage 31, which is located at the common boundary of the refining zone 10 and the conditioning zone 13, this boundary or corset has a narrower width than that of the current, and the current is forced to go through the passage 31.Thus the homogeneity of the glass is increased at drawing off.

Abstract: An apparatus for mixing or homogenizing viscous material is disclosed. Stirrers, comprising multiple vane mixing blades are mounted on a pair of parallel shafts in corresponding spaced apart parallel tiers. Each vane has a working surface inclined relative to the shaft and offset relative to the vanes of an immediately adjacent blade. One shaft is advanced relative to the other so that the vanes intermesh. The inclination of the vanes in one blade is mirrored in sense to the other blade on the adjacent shaft, and the shafts are rotated in opposite sense so that the stirrers in each tier pump the material in the same relative direction when the shafts are so rotated.

Abstract: A continuous tank-type glass melting furnace includes a melting zone into which raw materials are charged and reduced to a molten state. The molten glass then flows through a relatively narrow waist or conditioning area to refining and conditioning zones, and is then withdrawn as a continuous ribbon or sheet. Within the waist area there is provided a plurality of stirrers whose mixing and kneading action assist in homogenizing the glass as it flows through the restricted area. Each stirrer is connected to and driven by its own individual power unit so that the speed and direction of rotation of individual stirrers can be independently regulated and synchronized. Individual stirrers can also be removed and replaced with little or no interruption in operation of the remaining units.

Abstract: An improved method of preparing a molten glass composition is presented. The constituents of the molten glass composition are classified into two or more melting groups according to mutual melting properties or characteristics such as volatility, corrosiveness or fusion point. Of the constituent groups one is selected and prepared as a molten base glass composition into which the remaining groups are sequentially introduced and homogenized into the base glass forming a molten glass composition of desired forming characteristics.

Abstract: A process for controlling the composition, viscosity, resistivity or other variables of a molten glass by sensing temperature and resistivity or viscosity and making corrections in accordance with the deviation of the sensed properties and desired properties of the glass, as for example, a desired viscosity and/or composition.

Abstract: Disclosed is an improved stirrer for homogenizing glass in a forehearth of a glass furnace. It comprises a paddle having both upwardly and downwardly slanting holes that is reciprocated in the manner of a hoe back and forth across the forehearth. A novel drive linkage causes the paddle to raise and lower as it passes back and forth to produce a clawing action for better mixing.

Abstract: At least two differently colored components of glass are heated to a molten, viscous state and then combined in a channel shaped forehearth to form a confluent of molten glass in which the starting components remain in discrete domains, delineated by abrupt color transitions at the interfaces between such domains. The confluent flows by gravity to a discharge end of the forehearth, at which the molten glass is fed between a pair of forming rollers which press it into a continuous, elongate sheet of variegated glass. While flowing toward the discharge end of the forehearth, the molten glass is subjected to controlled, limited stirring to break up relatively large domains of homogeneous color into a multitude of smaller randomly dispersed domains characterized by streaks, swirls and waves of individually identifiable colors.

Abstract: Disclosed is an improved stirrer for homogenizing glass in a forehearth of a glass furnace. It comprises a paddle having both upwardly and downwardly slanting holes that is reciprocated in the manner of a hoe back and forth across the forehearth. A novel drive linkage causes the paddle to raise and lower as it passes back and forth to produce a clawing action for better mixing.

Abstract: Molten glass is conditioned to achieve a desired thermal distribution suitable for feeding the glass to a forming process. The molten glass is fed to the inlet end of a conditioning zone of a tank and glass flow through the conditioning zone is established in a direction towards a remote outlet from that zone with substantially no return flow. The glass is selectively cooled adjacent the inlet to the conditioning zone to achieve a desired temperature profile through the depth and width of a transverse cross section adjacent the conditioning zone inlet so that on flowing through that zone the further conditioning completes transformation of the glass to a state suitable for feeding to the forming process. The cooling is effected at a position selected in dependence on the temperature distribution within the glass and the required temperature profile by passing cooling fluid through at least one fluid cooled pipe immersed in the molten glass located in the forward flowing body of the glass.

Abstract: A glassmaking furnace having a melter and a refiner joined through a waist is provided with a plurality of glass stirrers positioned transversely across the intended path of glass flow through the waist. Each stirrer comprises two coaxial pipes, an inner pipe and an outer pipe, the outer pipe having a bent loop extension at one end, such that one end of the bent loop extension is in communication with the annular space between the pipes and the other end is in communication with the inner pipe. Each stirrer is provided with means for supplying a coolant to the pipes and means for rotating the stirrer in order to homogenize glass before it is fully refined by appropriate thermal conditioning in the refiner of the furnace.

Abstract: An elongated tank body of a glass melting apparatus defines a melting region adjacent its inlet end, a refining region downstream, a conditioning zone adjacent its outlet end and an intermediate zone leading from the refining region to the conditioning zone. The intermediate zone and conditioning zone are substantially narrow relative to the refining region. Flow control means physically slows up the forward flow of the upper levels of glass out of the refining region and into the narrower zones. The refining region and intermediate zone are sufficiently deep for forward and return flow of molten glass to take place. A step is located at the upstream end of the conditioning zone which has a raised base providing a shallow conditioning along which molten glass flows toward the outlet with substantially no return flow.

Abstract: This invention relates to a fusion and casting machine for the preparation of glass buttons for analysis.The machine contains an assembly of several heaters which moves with a precession motion imparting agitation to the content of the molten materials. When the materials are fused, agitation stops, flame goes out, moulds which were intially above the crucibles move under the crucibles, and the crucibles turn over and transfer their content into the moulds where solidification takes place. Perfect glass buttons are produced: these are stable, homogeneous, flat, smooth, bubble-free and need no further processing before the anaylsis.

Abstract: A particular range of glass compositions in the soda-boro-silicate glass system has been found to be particularly suitable for ultra-low loss dielectric optical waveguides. The composition range is indicated in FIG. 1 of the specification. By preparing such glasses in a reducing atmosphere (0-2% CO in CO.sub.2) and adding about 1% As.sub.2 O.sub.3 to the melt attenuation coefficients due to copper and iron can be minimized. The water content of the glass can be reduced by bubbling dry CO in CO.sub.2 through the molten glass. Glasses containing less than 30% Na.sub.2 O by weight have the lowest losses. Using glasses of this type dielectric optical waveguides having an insertion loss of less than 14 dBKm.sup.-.sup.1 have been made.

Abstract: Method and apparatus are presented for thermally intermixing, blending and homogenizing additive constituents into a molten host glass composition as it flows through a forehearth channel. The additive composition in solid or molten form, is introduced into a thermally rising flow of molten host glass and thermally intermixed therein by successive descending and rising thermal currents.

Abstract: In a glass melting tank stirrers are provided between the refining and conditioning zones. The stirrers extend side by side across the path of forward glass flow and are driven by a motor so that they rotate about vertical axes out of phase with each other.

Abstract: An apparatus for refining molten glass comprising a shell mounted in a generally vertical position and having an intermediate cylindrical portion and frusto-conical end portions, refractory material within the shell defining a glass-receiving chamber. The shell is supported by bearings mounted upon a base and engaging the frusto-conical end portions of the shell. Drive means are interposed between the lower frusto-conical end portion and the lower bearing for rotating the shell about its generally vertical axis. A housing surrounds the shell. The shell is cooled by circulating air continuously in the area between the shell and the housing. The bearings are both lubricated and cooled by forcing oil about the bearings. Unrefined molten glass is delivered to the upper end of the shell, rotated, and the refined molten glass is removed from the lower end of the chamber.

Abstract: In a glass melting tank a water cooled barrier extends horizontally across the forward flow of molten glass to control the forward flow towards the working end and a plurality of stirrers, rotatable in phase with each, are arranged side-by-side across the flow path adjacent the barrier.

Abstract: A method for rapidly melting glass-making materials wherein the glass-making materials are introduced into a chamber containing molten glass, heat is applied to the materials in the chamber by passage of an electric current between spaced electrodes while one of the electrodes is moved within the molten materials to agitate the materials to constantly move the location of the heating point through the batch glass-making materials and to enfold newly-added glass-making materials into the molten glass within the chamber.

Abstract: A stirrer for stirring molten glass comprises a stirring member for immersion in molten glass, a rotary shaft extending upwardly from the stirring member so that in use the shaft may extend above the molten glass and connect the stirring member to a drive device, a platinum or platinum alloy hollow casing surrounding the rotary shaft in spaced relationship thereto, the casing terminating above the stirring member, and separate inlet and outlet means in the casing for introducing and removing a flow of inert gas through the space between the casing and the shaft.

Abstract: In accordance with the method and apparatus of this invention, glass-forming materials are subjected to heat and agitation sufficient to form a molten glass having mostly dissolved glass-forming materials, mostly completed chemical reactions between the glass-forming materials and containing a high number of gaseous inclusions, and containing up to 50 volume percent entrapped gases. This glass appears foamy. The molten glass is transferred to a second chamber to complete melting of any unmelted sand grains remaining from the glass-forming materials, and completes the chemical reactions that remain incompleted, and to remove any remaining cords, and to reduce the foamy character of the melt to a dense molten glass which contains only small-sized gaseous inclusions.