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: An arc discharge method includes the steps of heating and melting a non-conductive object by arc discharge using a plurality of carbon electrodes in a output range of 300 to 12,000 kVA; and setting a ratio of the distance between a contact position at which the carbon electrodes come in contact with each other and a front end to the diameter of the carbon electrode during the start of the arc discharge to be in the range of 0.001 and 0.9.

Abstract: An electrode holder for use in a furnace for melting a batch material to form molten glass is disclosed comprising a refractory coated nose member presented to and in contact with a molten glass material contained within the furnace. The refractory coating is preferably a flame- or plasma-sprayed ceramic such as alumina or zirconia. That protects the nose member from corrosion from the hot molten glass.

Abstract: The present invention provides a process for producing a molten glass which can produce a molten glass having a good quality, a glass-melting furnace, a process for producing glass products and an apparatus for producing glass products. While an oxygen combustion burner 20 is rotated by a motor 38, glass raw material particles (not shown) are dropped into a high-temperature gas phase atmosphere produced by a flame F of the oxygen combustion burner 20, to be changed into liquid glass particles. By rotation of an outlet (nozzle) of the oxygen combustion burner 20, the falling position of the liquid glass particles 26, 26 . . . changes with time. Accordingly, generation of bubbles caused by continuous fall of the liquid glass particles in a particular position on a molten glass liquid surface is prevented. Accordingly, it is possible to produce a molten glass having a good quality with few bubbles.

Abstract: An arc discharge method of the present invention includes the steps of: heating and melting a non-conductive object by arc discharge using a plurality of carbon electrodes in an output range of 300 to 12,000 kVA; and setting a ratio of the distance between a contact position at which the carbon electrodes come in contact with each other and a front end to the diameter of the carbon electrode during the start of the arc discharge to be in the range of 0.001 to 0.9.

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: The present invention is to provide an all-electric glass-melting deep furnace and a method of refining and supplying glass in which high-quality molten glass can be efficiently produced in large quantity at high heat efficiency. An all-electric 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 method of the present invention makes it possible to remove seeds which are generated when glass raw material are melted.

Abstract: The invention relates to a device for the production of a glass melt from a batch; with a melt tank (1) that has peripheral walls (1.1-1.4) and a bottom (1.5); with a discharge channel (2) which is located under the bottom (1.5) of the melt tank (1) and which is in conducting connection with the melt bath (3) over an entry opening (2.3) and has an outlet opening (2.4) for the finished melt in the zone of a peripheral wall (1.1) of the melt tank (1); with at least one heating arrangement for the heating of the melt bath (3); the entry opening (2.3) of the discharge channel (2) is arranged in a central zone of the bottom (1.5) of the melt tank (1); the discharge channel (2) has a covering (2.2) which is located at least approximately at the level of the bottom (1.5) of the melt tank (1).

Abstract: A glass melting tank with at least one pair of heating electrodes projecting into the glass melt and a process for melting glass are described. The glass melting tank has, at least in the area of the melt, a narrowed cross section area and the glass melting tank has at least one heating electrode in front of and a corresponding heating electrode behind the narrowed cross section area and in this way an increase in the temperature of the melt can be achieved in the narrowed area. A preferred application is the refining of glass melts.

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 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 melting furnace for thermal treatment of heavy metal-containing and/or dioxin-containing special wastes, including a clog preventing system including a principal furnace vessel, which exhibits a melting tank for holding a melt; at least one feeder for feeding the material to be treated; a discharge chamber, which is at a spatial distance from the feeder, the feeder being connected gas-tight via a siphon to the melting tank; the principal furnace vessel and the discharge chamber having third heating elements in the form of bath electrodes, by means of which an electric current can be run through the melt and the siphon for additional heating of the melt.

Abstract: A glass melting tank provides heat in a melting chamber 11 from pairs of electrodes 26, 27 and 28. A three-phase electrical power supply 34 provides power to the electrode pairs and the voltage supplied for the different phase is independently controlled by a power control 33.

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 bottom outlet device is provided for a glass melting furnace, with heating of a glass melt being effected to within the temperature range of the electrical conductivity of the melt by way of electrodes disposed in the interior of the furnace and projecting into the melt. An inductively heatable and metallic outlet unit projects from the bottom of the furnace and includes an outlet opening and an interior outlet channel communicating with the outlet opening. An outlet block comprised of ceramic bricks is disposed above the outlet unit and includes a throughgoing channel which opens toward the interior of the furnace and which is flush with the interior outlet channel of the outlet unit. A bottom electrode comprised of metal is disposed at a lowermost portion of the interior of the furnace. The bottom electrode is penetrated by a further channel which is flush with the throughgoing channel in the outlet block and is thereby in communication with the outlet opening of the outlet unit.

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: An electrical melting technique for glass, more specifically, a technique wherein the conductivity of the molten glass is used to develop the energy necessary to melt the raw materials. Energy is dissipated by a Joule effect into the molten mass from vertical plunging electrodes, with the composition to be melted being spread in a uniform layer on the surface of the bath. The electrodes are arranged at a distance from the refractory walls of the tank, with the distance separating the electrode from the closest lateral wall being at least half that separating two adjacent electrodes and the position of the level of the maximum temperature being regulated by the depth of immersion of the electrodes.

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 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: An electric melting furnace is described for melting high electrical resistivity glass, such as E-glass, within a melting chamber surrounded by a relatively low electrically resistivity refractory, such as chromic oxide refractory, by utilizing interconnected peripherally positioned batch electrodes at substantially the same potential as the chromic oxide walls and centrally positioned electrodes which are immersed a greater distance than the batch electrodes. A quiescent zone is formed adjacent a lower portion of the melting chamber and the batch blanket and effective hydrostatic head of the molten bath are adjusted by controlling the immersion of the batch electrodes within the molten bath.

Abstract: A melting furnace is disclosed which heats by joule effect to supply molten material of uniform temperature at the floor of the melter. During formation of molten material, an essentially isothermal condition across a given horizontal plane of the body of molten material is established. Spaced apart opposed electrodes and controlled current flow establish these uniform temperatures and allow molten material to be formed directly from the melter without further processing.

Abstract: Disclosed is a method for protecting the heating electrodes of glass melting furnaces by applying a DC potential to various electrodes of the furnace. The DC current is applied to the heating electrodes through counter electrodes or anodes. The method of this invention not only reduces the corrosion of the heating electrodes but also reduces the corrosion of the counter electrodes.

Abstract: In an electrode arrangement utilized for heating electric crucibles in glass melting processes, each electrode consists of several spaced electrode plates arranged in parallel and attached to connecting elements. The connecting elements of two neighboring electrodes are disposed in parallel to one another, and the electrode plates of each electrode are staggered with respect to those of the adjacent electrode by half the plate spacing. By using this arrangement, the electrode plates project into the space between the neighboring electrode plates. Consequently, a larger heat output per unit volume of glass melt is achieved without endangering the integrity of the refractory material of which the crucible is made.

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.

Abstract: An electric fusion furnace for a vitrifiable charge wherein the fusion energy of the furnace is dissipated by the Joule effect in the molten mass, comprising a furnace having electrodes vertically disposed therein which are attached to the bottom of the hearth of the furnace and which are distributed regularly over the entire surface of the hearth in at least one ordered grouping of two rows with each row comprised of three equidistant electrodes powered in three respective phases designated as R, S, and T, wherewith the order of the phases in the two rows is inverted (R, S, T, and T, S, R), such that the two middle electrodes are in phase and the pairs of electrodes on the respective ends are in different phases, and wherewith the interelectrode distance in a given row is approximately equal to the distance between the two rows.

Abstract: A glass melting furnace which uses Joule effect heating between electrodes, has a parallel attachment of electrodes to a single power source. The electrodes are arranged in rows of four electrodes across the width of the furnace. Multiple rows of electrodes spaced along the length of the furnace are used. The electrodes within a row are connected in a parallel format such that the current flow within a row can only be between two electrodes which are adjacent to each other. A current limiting controller and thermal currents within the molten glass balancing the temperature within the molten glass.

Abstract: A conditioning section of a forehearth is disclosed with sidewall electrodes for Joule effect heating of glass positioned and connected to confine the current and Joule effect heating separately to the side portions of the molten glass flow path therein. Separate circuits, controls, temperature sensors and temperature set point control means are provided for the sidewall electrodes on each side. Glass temperature across the flow path is controlled and can be adjusted by separately controlling the flow of Joule effect current along each side of the flow path through manual or automatic, thermally actuated, controls for each side.

Abstract: A continuous process of making glass, in which a vitrifiable batch is fed to a furnace equipped with heating devices for melting the batch so as to produce molten glass. The furnace has a melting end into which the batch is fed and a delivery end remote from the melting end and from which delivery end molten glass is withdrawn. The furnace presents a melting zone adjacent the melting end, in which the batch is melted. The melting zone is composed in the vertical direction of an upper half constituting a batch zone and of a lower half, and the melting zone is further composed in the horizontal direction of an upstream half proximate to the melting end and of a downstream half remote from the melting end. In order to promote melting of the vitrifiable batch, to thereby improve the quality of the glass produced, a direct electric current is established, during the process, between at least one cathode located in the upstream half of the batch zone and at least one anode located outside the batch zone.

Abstract: In a glass-melting furnace, electrodes are inserted through the batch in symmetrical locations spaced from sidewalls of the furnace. Melting and refining take place in relatively narrow bands below the batch.

Abstract: A furnace for the melting of glass in which horizontally spaced regions of the molten glass body are heated by passage of alternating electric current between diagonally opposed electrodes of two groups and supplied from a primary power supply circuit, and in an intervening zone above a withdrawal path leading to an outlet auxiliary electrodes spaced apart longitudinally of the zone are fed with current from an auxiliary supply circuit including regulators providing for adjustment of the heating effect along different parts of the zone to set up a convective effect balancing any downward pull which could draw unrefined glass or batch material into the withdrawal path.

Abstract: An electric furnace for heating glass by the Joule effect comprising: a chamber adapted for holding a body of molten glass; a plurality of electrodes positioned in the chamber such that the electrodes form a zone with two clusters of electrodes in the zone, the clusters being located on opposite sides of the chamber, each of the clusters comprising first and second sets of electrodes, the first set being positioned closer to the other cluster than the second set and the first and second sets being positioned such that the second set of electrodes carries at least 60% of the current carried by the first set; and a source of power connected to the clusters.