Abstract: Provided is an alkali-free glass substrate having a high strain point and excellent bubble count, and a method for manufacturing the alkali-free glass substrate. The method includes: a batch preparing process of preparing a raw material batch so as to obtain alkali-free glass containing, in mass %, 50 to 80% of SiO2, 15 to 30% of Al2O3, 0 to 4.5% of B2O3, 0 to 10% of MgO, 0 to 15% of CaO, 0 to 10% of SrO, 0 to 15% of BaO, 0 to 5% of ZnO, 0 to 5% of ZrO2, 0 to 5% of TiO2, 0 to 15% of P2O5 and 0 to 0.5% of SnO2 as a glass composition; a melting process of melting the prepared raw material batch; a fining process of fining the molten glass; and a forming process of forming the fined glass into a sheet shape. The raw material batch is melted such that a bubble enlarging temperature of the obtained glass is lower than a maximum temperature of the fining process.

Abstract: A melting apparatus is disclosed, the melting apparatus including a melting vessel with a back wall, a front wall, a first side wall, a second side wall and a longitudinal centerline extending therebetween and a width between the first and second side walls orthogonal to the centerline. The melting vessel further includes a first feed screw including a first axis of rotation and a second feed screw including a second axis of rotation, the first axis of rotation positioned between the longitudinal centerline and the first side wall and the second axis of rotation positioned between the longitudinal centerline and the second side wall. The positions of either one or both the first and second axes of rotation are located from a respective side wall a distance that is equal to or less than about 15% of the width of the melting vessel.

Abstract: Provided is a manufacturing method for a glass article, including: a supply step of supplying glass raw materials (4) onto a molten glass (2) accommodated in a melting chamber (3) of a glass melting furnace (1); a melting step of melting the supplied glass raw materials (4) through heating; and an outflow step of causing the molten glass (2) to flow outside the melting chamber (3), wherein the glass raw materials (4) supplied from one screw feeder (5) and another screw feeder (5), which are adjacent to each other out of a plurality of screw feeders (5), extend in parallel through intermediation of a gap (6) on the molten glass (2), and wherein the glass raw materials (4) are melted through heating only with an electrode (8) and an electrode (9) each immersed in the molten glass (2) in the melting chamber (3).

Abstract: A system and method is provided for identifying degrading electrodes in a marine electromagnetic survey system. A system may comprise a sensor array operable for use in a marine electromagnetic survey system, wherein the sensor array comprises a plurality of electrodes. The system may comprise a shunt resistor connected to the electrodes and a processor operable to vary a resistance of the shunt resistor in the presence of a voltage across the electrodes. A method for identifying degrading electrodes may comprise measuring an electric field in a body of water with a pair of electrodes, wherein a shunt resistor is connected between the pair of electrodes. The method may comprise varying a resistance of the shunt resistor. The method may comprise measuring a voltage across the shunt resistor while varying the resistance of the shunt resistor to obtain measured voltages for different shunt resistor values.

Abstract: In an apparatus, a synchronizing unit synchronizes a measurement timing of values of first and second phase currents by a current sensor with a measurement timing of a rotational angle of a rotor by a rotational angle sensor. A current calculator calculates, based on the first and second parameter signals and the rotational angle of the rotor, values of two phase currents in a rotational coordinate system defined with respect to the rotor. A transmitter transmits the values of the two phase currents using a communication protocol. A controller communicates with the transmitter using the communication protocol to receive the values of the two phase currents. The controller controls the first phase current, the second phase current, and a third phase current flowing through respective first, second, and third phase windings of a three-phase rotary machine according to the values of the two-phase currents.

Abstract: An electric glass hot shop system is described herein that has at least one electrically powered heating unit (e.g., electric furnace, electric glory hole, electric pipe warmer, electric color box, electric annealer, electric crucible kiln) used in the processing of glass.

Abstract: An electric glass hot shop system is described herein that has at least one electrically powered heating unit (e.g., electric furnace, electric glory hole, electric pipe warmer, electric color box, electric annealer, electric crucible kiln) used in the processing of glass.

Abstract: The invention relates to a method for ceramizing starting glass of glass-ceramics into glass-ceramics, comprising at least the following steps: 1.1 the starting glass is heated from an initial temperature T1 to a temperature T2 which is disposed above the glass transformation temperature TG at which crystallization nuclei are precipitated; 1.2 the glass is held at the temperature T2 for a period t2 for the precipitation of crystallization nuclei; 1.3 the glass is further heated to a temperature T3 at which a crystal phase grows on the nuclei formed following step 1.1 and 1.2; 1.4 the glass is held for period t3 at a temperature T3 or heated during this period to a higher temperature T4 until the predetermined properties of the glass-ceramics have been reached; 1.5 the control of the temperature curve is performed with the help of a control loop comprising at least one temperature sensor for sensing the temperature and a heating unit as an actuator. The invention is characterized in that 1.

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: 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: 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 method of controlling the course over time of a target temperature of a molten metal in a ladle, for example, in which the required heating power is produced by at least one plasma torch. Determination is made of the variation with time of a target temperature, the mass of an outwardly flowing melt, and a specific heat value of the melt present in the ladle. From the foregoing values there is ascertained the course of a corresponding setting signal for obtaining the heating power necessary to obtain the desired temperature course. Simultaneously and continuously the actual temperature of the melt is measured. When the actual temperature of the melt deviates from its target temperature in excess of a predetermined tolerance, the setting signal for the heating power is changed by decreasing such setting when an actual temperature exceeds the target temperature, and increasing such setting when an actual temperature is less than the target temperature.

Abstract: A bushing balance controller controls the overall average temperature of a multiple segment glass fiber forming bushing and the temperature of each individual bushing segment. Current shunting loops divert current away from each bushing segment as required to provide the proper bushing segment temperature profile as well as the desired average bushing temperature.

Abstract: A bushing balance controller senses the temperature of each section of a multiple section glass fiber forming bushing by thermocouples or resistance (voltage drop) measuring techniques and injects electrical energy to all but one of the individual bushing sections and adjusts the supply of electrical energy to the entire bushing assembly thereby controlling the temperature of each individual section of the bushing. When thermocouples sensors are utilized, standard thermocouple driven temperature controllers may be utilized to provide a signal to a plurality of power packs, a primary power pack providing electrical energy to the entire bushing and smaller power packs controlling the injection of electrical energy to all but one of the bushing segments. A similar power pack and bushing control scheme accompanies the use of resistance (voltage drop) measurement techniques.

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 bushing balance controller is an electronic device which measures the voltage drop across each segment of a multiple segment glass fiber forming bushing and measures the current flow in the bushing. The device uses these measurements to produce error signals proportional to the difference in the set point temperature and the instantaneous temperature of each segment of the bushing. The device diverts current from each segment of the bushing whose error signal is greater than the average of the error signals for all segments of the bushing. The device also sums all error signals and passes this signal to a bushing controller which adds current to the bushing when the sum of the error signals falls below a preset value.

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: A circuit for performing a method melting vitreous materials in an electric furnace wherein the electrodes are supplied with an alternating current of optimal frequency lower than 60 or 50 Hz, respectively, the corrosion of electrodes being minimized. The circuit comprises a cycloconverter which changes a three-phase current supply into a single-phase current with a simultaneous changing of the input mains frequency into an optimal output frequency. The circuit also comprises a device for measuring and/or controlling the direct current component of the low frequency feeding alternating current, in order to stabilize the favorable anticorrosion effect of the low optimal frequency. Further, it comprises a device for the control of the power input of the cycloconverter with respect to the melting temperature in the furnace.

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 system for converting fly ash into mineral wool including an airtight chamber enclosing a molten stream from a spinner and providing an adjustable access to a bin for receiving shot and including an airflow device for drawing air from the bin, through the adjustable access, past the spinner, and into an accumulator, with the adjustable access being operable to selectively limit the rate of flow of the air to thereby control the average weight of fibrous strands entering the accumulator is also disclosed. The quality of accumulated strands is also controlled through a system including a spinner for converting a molten stream into an output of fibrous strands and shot, a cyclone, and a collector with conduit means delivering fibrous strands from the spinner to cyclone and from a light fiber vortex exit or the cyclone to the collector. Preferably, the cyclone includes a variably positionable vortex exit tube. Methods are taught using the above-identified apparatus to generate a high quality mineral wool.

Abstract: In a method of melting vitreous materials, the thermal energy to be supplied electrically to the vitreous mass is controlled by supplying the melting plant according to supplying cycles consisting of pre-established intervals of time during which the power applied to the plant is much higher than the maximum permissible input when the plant is continuously supplied, spaced by pre-established intervals of time during which the plant is not supplied. The length of said intervals of time is equivalent to an integral number of cycles of the alternating voltage acting on the electrodes.

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: A system for generating in-phase alternating current components which are fed into a medium held in a melting trough and flow in the medium between electrodes and counterelectrodes immersed in the medium to effect resistance heating. One embodiment of the system includes a supply voltage source, and a plurality of transformers each having a primary winding and a secondary winding, with the primary windings being connected together in series and to the source, each secondary winding being connected between a respective electrode and counterelectrode to provide a respective alternating current component, and each winding having a number of turns corresponding to the desired relative amplitudes of the current components.

Abstract: A high temperature electronic furnace wherein a product-containing vessel has a product exit orifice, a plurality of electrodes are located in the vessel to define primary current paths adjacent the orifice, a control electrode is positioned in the vessel for defining an additional current path adjacent the orifice and a circuit for energizing the primary electrodes with multiphase current and for time-sharing the multiphase current with the control electrode. The degree of time-sharing is made responsive to the temperature of product passing through the orifice and/or the rate of flow of product passing through the orifice. In addition, the control electrode is moveably positioned with respect to the orifice, with the position of the control electrode being dependent upon the temperature of product passing through the orifice and/or the rate of flow of product through the orifice.

Abstract: Molten glass entering from a refiner is conditioned, in an optimum operation, such that its temperature along the center of the flowing glass just in advance of its entry into the feeder, will be of equal temperature near the surface near the bottom and intermediate these two points. A tri-level thermocouple is positioned along the center line at approximately nine inches from the feeder for monitoring these temperatures, and to serve as an aid to the operator in controlling the actual glass temperature. Positioned at opposite sides of the forehearth, approximately eight inches from the center line, are tri-level thermocouples. The three couples will be positioned at the same relative depths as those at the center line. The center thermocouple on the right side will have its output used as the control temperature for a temperature override circuit connected to the electrodes.

Abstract: An electric melting furnace is provided for optimally melting and mixing a non-homogeneous material. The melting furnace includes a vessel having its top portion open to the environment. Three electrodes are supported above the furnace. Each of the electrodes includes a tip for insertion into the material contained in the vessel. The vessel further includes an outlet formed in the bottom wall of the vessel to discharge the material after it has been melted and optimally mixed. Each of the three electrode tips has a generally round configuration. During the melting operation, the three electrode tips are laterally spaced from each other and are positioned in the vessel to be surrounded by molten material but above the bottom wall outlet. Optimum melting and then optimum mixing of the material occurs at selected horizontal spacings of the electrode tips and at selected electrode tip immersions in the molten material.

Abstract: A method and a system for uniformly heating a glass stream flowing in the feeder of a glass melting furnace wherein power or energy is supplied through the electrodes immersed in the glass melt and wherein the temperature of the glass stream is continuously detected, has the current flowing between cooperating electrodes maintained constant independently of the resistance defined by the glass melt by controlling the voltage as long as the temperature of the glass stream does not deviate from predetermined limits and the current flow of at least a number of electrodes positioned at the inlet of the feeder are controlled to compensate for temperature variations when the tolerable deviation limit has been exceeded.