Abstract: A crucible for growing a metal oxide single crystal is provided that can facilitate the balance between the thickness and the strength (hardness) of the constant diameter portion of the crucible and is capable of performing growth of a crystal having a large diameter. The crucible according to the present invention is a crucible for growing a metal oxide single crystal, including a reinforcing belt material provided on an outer periphery of a constant diameter portion of the crucible. It is possible that the crucible has an upper portion having a thickness that is smaller than a thickness of a lower portion of the crucible, and the upper portion of the crucible is the constant diameter portion.

Abstract: An energy-efficient device for refining a glass melt to produce a glass and/or a glass ceramic is provided. The device includes a refining crucible defined at least by lateral walls with a metallic lining as a melt contact surface, so that a melt refining volume is defined by a base surface, a top surface and a circumferential surface; at least one heating device that conductively heats the lining by an electric current in the lining, so that the melt is heated through the lining, the heating device and the lining are connected to one another by a feeding device. The feeding device establishes contact with the lining so that an electric current runs from the top surface to the base surface or from the base surface to the top surface, at least in sections of the lining.

Abstract: A waste vitrification apparatus (10) having rotatable mixer impeller (16) functioning as a shaft electrode (60) and metallic vessel (14) functioning as a vessel electrode (62). A stream (12) of waste material and vitrifiable material are mixed and melted in the vessel (14) for vitrification. The waste vitrification method converts a feed stream (12) by mixing the feed stream into a glass melt (13) and melting glass batch of the feed stream (12) to form a foamy mass. The stream is dispersed by the impeller (16) to form a foam which is then densified in a settling zone (22), recovered through a spout (24) and solidified in storage containers. Means are provided to adjust the location of the mixing impeller (16) in the vessel (14) to change the depth of the settling zone (22). The impeller (16) is mounted on a drive shaft (18) having a recirculating coolant flow.

Abstract: A waste vitrification apparatus (10) having rotatable mixer impeller (16) functioning as a shaft electrode (60) and metallic vessel (14) functioning as a vessel electrode (62). A stream (12) of waste material and vitrifiable material are mixed and melted in the vessel (14) for vitrification. The waste vitrification method converts a feed stream (12) by mixing the feed stream into a glass melt (13) and melting glass batch of the feed stream (12) to form a foamy mass. The stream is dispersed by the impeller (16) to form a foam which is then densified in a settling zone (22), recovered through a spout (24) and solidified in storage containers. Means are provided to adjust the location of the mixing impeller (16) in the vessel (14) to change the depth of the settling zone (22). The impeller (16) is mounted on a drive shaft (18) having a recirculating coolant flow.

Abstract: An all-electric glass-melting deep furnace and a method of refining and supplying glass are disclosed in which high-quality molten glass is efficiently produced in large quantity at high heat efficiency. The glass-melting deep furnace 20 has a bottom 2 and a side wall 4 constructed by piling up fireproof bricks 3 on the perimeter of the bottom 2. A height H of the side wall 4 is set to be twice or more than twice as long as an inside dimension D of the bottom 2 of the furnace. Since the furnace 20 is deep, there can be achieved a thick batch layer, a space in which glass is melted at high temperature, and a cooling area which is necessary to refine molten glass. The furnace makes it possible for the molten glass 6 to absorb fine seeds by its pressure and cooling effects that are produced when the seeds move downward to the bottom 2.

Abstract: This invention relates to a device for melting or refining glass or glass ceramics. According to the invention, such a device is provided with the following characteristics: a channel which is arranged in an essentially horizontal manner and which is provided with an inlet and an outlet for the glass melt; and an HF coil for coupling HF energy into the melt is allocated to the channel. The channel is made of a plurality of metal pipes in a similar way to a skull pot. Said pipes can be connected to a cooling medium.

Abstract: An arc furnace that utilizes a combined DC arc system and an AC joule heating system to melt the waste disposed therein and to keep the waste material in a molten condition. The DC arc system utilizes the AC joule heating electrodes as part of the DC current path, thereby eliminating the need for a counter DC electrode. Furthermore, the AC joule heating system provides for peripheral and radial AC current flow to neighboring AC joule heating electrodes, thereby creating a stirring effect in the molten waste. This design greatly simplifies the arc furnace control system while providing a more effective thermal control of the molten waste.

Abstract: An arc furnace that utilizes a combined DC arc system and an AC joule heating system to melt the waste disposed therein and to keep the waste material in a molten condition. The DC arc system utilizes the AC joule heating electrodes as part of the DC current path, thereby eliminating the need for a counter DC electrode. Furthermore, the AC joule heating system provides for peripheral and radial AC current flow to neighboring AC joule heating electrodes, thereby creating a stirring effect in the molten waste. This design greatly simplifies the arc furnace control system while providing a more effective thermal control of the molten waste.

Abstract: In a glass melter, a precious metal insert is used to protect a gas bubbler from corrosion at the orifice of the bubbler through which gas is injected into the melt. The use of a precious refractory metal insert at the bubbler orifice prevents the attack of molten glass on the bubbler. The precious metal is chosen from the refractory group of metals and the platinum group of metals. Preferably the precious metal from the platinum group is platinum or one of its alloys or one of ruthenium, rhodium, palladium, osmium and iridium. The precious metal from the refractory group is preferably chromium.

Abstract: The invention relates to the electric melting technique, in which the melting energy is dissipated in the bath of melted glass as a result of the Joule effect by means of electrodes which dip through the surface of the bath. According to the invention, the electrodes dip into a bath of melted glass which has a height h below 800 mm and a surface S such that the ratio h/S is lower than 0.5 m/m.sup.2. According to another aspect, the exchange surface between the electrodes and the bath is above 0.075 m.sup.2 /m.sup.3 of glass.The invention is used in the manufacture of glass-based products, such as insulating materials based on glass fiber.

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: An apparatus for processing various hazardous waste materials by melting in a vessel for subsequent solidification is disclosed which includes a seal for the cover thereof. Melter includes a high-speed mixing impeller powered by a drive shaft which extends through an opening in the cover. The vessel is electrically heated by discharge of electrical energy through the melt contained in the vessel. In one embodiment the impeller and shaft are included in the electrical heating circuit. A shaft seal engages the shaft at a point spaced from the cover. An axially extensible seal seals a space bounded by the shaft seal and the opening in the cover. Purge gas is supplied to the sealed space to provide positive gas flow from the sealed space into the vessel. A cold wall transport duct for off-gas porting is disclosed. A bottom drain structure including a sleeve and plug is also disclosed. The output of the melter may be subsequently heated in a holding tank to refine the output.

Abstract: A glass melter having a lid electrode for heating the glass melt radiantly. The electrode comprises a series of INCONEL 690 tubes running above the melt across the melter interior and through the melter walls and having nickel cores inside the tubes beginning where the tubes leave the melter interior and nickel connectors to connect the tubes electrically in series. An applied voltage causes the tubes to generate heat of electrical resistance for melting frit injected onto the melt. The cores limit heat generated as the current passes through the walls of the melter. Nickel bus connection to the electrical power supply minimizes heat transfer away from the melter that would occur if standard copper or water-cooled copper connections were used between the supply and the INCONEL 690 heating tubes.

Abstract: A silicon carbide whisker production apparatus manufactured by placing a plurality of lidded reaction vessels in the longitudinal direction of an Acheson furnace at intervals, packing graphite grains in the gaps between the adjacent reaction vessels and around the reaction vessels along the longitudinal direction of the furnace starting with the furnace-side ends of terminal electrodes to form a surrounding heating zone, and packing a heat insulating packing around the surrounding heating zone.

Abstract: A method of feeding glass to a glass-melting furnace for making a vitreous material, a heated airstream containing air at a temperature in excess of 1,000.degree. C. is passed down vertical cylinders towards the crown of the glass-melting furnace. Powdered glass batch is introduced into the vertically moving heated airstream in the lower and wider cylinder and infra-sound is applied to the vertically moving heated airstream by an infra-sound generator to vibrate the heated airstream and effect heat transfer from the airstream to the glass batch particles so that the glass batch particles are heated and the temperature of the heated airstream is reduced to a temperature below 700.degree. C., thereby reducing the propensity of the air to produce nitrogen oxides.

Abstract: A vertical glass melting furnace of the type having an inlet for raw materials at the top thereof, an outlet for molten glass at the bottom thereof, and a tabular electric resistance heating element for melting which is immersed at some level in molten glass, has at least one opening, and covers almost entirely the cross-section of the furnace at that level, the vertical glass melting furnace comprising a stirrer which extends from above the furnace and passes through the batch layer and the tabular heating element so that the stirrer brings about forced circulation for homogenization of the molten glass which has passed through the tabular heating element and stays in the region below the tabular heating element.

Abstract: In a melting furnace (1), toxic, volatile chemical compounds from introduced filter dust from industrial incineration units are vaporized at about 1300.degree. C. and forced to leave the reaction space. The non-vaporizing residue forms a glassy melt which is discharged continuously or intermittently from the reaction space. Heating of the melt and of the filter dust is affected by resistance heaters in protective ceramic sheaths (4) above the melt (2). In order to prevent corrosion of the resistance heater protection sheaths (4) by exit gases (7) especially in the flow lee thereof, the exit gases are forced, by partitions (10) and an exit gas extraction pipe (9) with an inlet orifice (16) at a low level, to flow below the resistance heater protection sheaths (4) to an exit gas outlet (5).

Abstract: A melting apparatus in which a material to be melted is accommodated in a crucible made of platinum or its alloy, and electric current passes through the crucible to generate heat ot melt the material. At least a part of the crucible is formed into a double-wall structure having inner and outer peripheral walls. The electric current is caused to pass through the double-wall structure to generate the heat.

Abstract: An electric melting furnace for vitrifying waste, having a melting tank having walls of refractory bricks, the melting tank being provided at the upper portion thereof with a supply port for a glass additive and waste and at the bottom portion thereof with a discharge port for molten glass containing the waste; at least a pair of side electrodes horizontally provided on opposite side walls of the melting tank; and at least one central electrode having a polarity opposite to that of the side electrodes, the central electrode being horizontally positioned in the interior of the melting tank at substantially the middle portion between the side electrodes. By such melting furnace construction, as described above, the heating current selectively flows through between the side electrodes and the central electrode, and does not flow electrically conductive substances deposited on the furnace bottom.

Abstract: A method for thermal decomposition treatment of a radioactive waste uses an apparatus comprising a container for holding molten matter of a radioactive waste containing a sodium compound, a pair of electrodes contacting the molten matter, and a power source for applying voltage between the electrodes while changing the polarity thereof every several tens of seconds. In this apparatus, the molten matter can be heated in the container by Joule heat, which is evolved by electric current directly flowed through the molten matter, so that the sodium compound contained in the radioactive waste can be decomposed, vaporized and removed to recover a stabilized radioactive solid as a residue in the container.

Abstract: An electric melting furnace for glassifying high-radioactive waste characterized in that, in a furnace for melting glass containing platinum-group elements which has an outlet of glass at the bottom part of a melting tank, the bottom of the furnace surrounding the outlet has an inclination of more than 30.degree. and not more than 70.degree. with respect to the horizontal plane toward the cullet, and the distance l.sub.1 between a surface-inside opening part of the outlet and bottom ends of at least a pair of electrodes (3a, 3b) for supplying most of power required for glass melting is a half or more, but not exceeding, of the distance (l.sub.2) between the electrodes (3a, 3b).

Abstract: A fiber glass bushing having a thermocouple embedded in the bottom thereof and a method of preparing the same is described. The thermocouple is carried in a plate member which is welded to the bushing bottom by a weld on the outside of the busing.

Abstract: An apparatus for more accurately measuring the temperature of a fiber glass forming bushing is described which includes the placing of sidewall and bottom thermocouples in locations on the bushing so that electrical signals representing noise are eliminated or reduced significantly.

Abstract: The joule melter has an outer cylindrical electrode which forms the outer wall of the melt containment, an inner cylindrical electrode which protrudes upward in the containment and forms the outlet for the melt, thus, also determining the depth of the melt. A non-conducting sealing material forms a base plug between the electrodes. A cylindrical electrically conductive baffle is located between the electrodes and includes an opening which allows the melt to flow from near the outer electrode where the melt material is first inserted into the melter, to the inner electrode which is the outlet. In addition to the inner and outer electrodes, the baffle may be connected to a power supply to modify the currents flowing at each of the electrodes.

Abstract: An apparatus for electrically heating conductive bulk materials by resistance Joule effect heating includes end and side walls defining an oven chamber having an inlet and an outlet. A plurality of pairs of generally planar electrode plates are angularly mounted with respect to the opposed end walls of the chamber and are electrically disconnected from one another. The electrode plates mounted to each end wall are disposed at the same angle and are arranged such that the upper edge of each electrode plate is at a different distance from the end wall than the lower edge of the plate, so that the planes of the plurality of electrode plates mounted to each end wall are substantially parallel and vertically displaced from each other. The electrical supply for each pair of electrodes plates is electrically isolated from that of each other pair. The amount of energy supplied to each pair of electrode plates is adjustable.