Abstract: A method and equipment for adjusting the temperature of glass sheets in a tempering furnace. The tempering furnace (1) comprises rollers (3) for conveying and oscillating the glass sheets (4) during heating, and resistors (5, 6) for heating the glass sheets (4) from above and from below. The temperature of the glass sheets (4) is measured inside the tempering furnace (1) during heating and the dwell time of the glass sheets (4) in the furnace is adjusted based on the temperature measurements. This enables exact control of the final temperature of the glass from the beginning, and the temperature can be kept uniform independently of the measures taken by the operator.

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: To compensate for disturbing influences during arc welding of at least two optical waveguide fiber ends, an impedance of the discharge path of the arc is measured and at least one of the welding parameters is varied based on the measured impedance.

Abstract: A semi-convective forced air system for heating glass sheets during a heating cycle. The system has a heating chamber, and a longitudinal conveyor extending lengthwise through the heating chamber. A plurality of longitidinally-extending air manifolds are located within the chamber and are in fluid connection with a compressed air source. The manifolds are arranged in at least one widthwise-extending column. Each of the manifolds are oriented parallel to the length of the conveyor and are constructed and arranged to create a downward flow of heated air toward the conveyor to convectively heat the entire length of selected widthwise portions of a sheet of glass on the conveyor. A controller supplies or restricts the flow of compressed air to selected manifolds within a column at predetermined times during the heating cycle.

Abstract: An apparatus for delivering a glass stream including a first inner layer and a second outer layer, including a generally vertical orifice, and delivering glass from a second source such that the glass from said second source provides an outer layer about the glass from the first source as it flows through the orifice. A resistance heated tube assembly is made of platinum or material having similar resistance heating properties and extends from a glass source to an orifice through which the glass flows from a glass source for the inner layer. The tube assembly includes a tube portion having an inlet end that communicates with the source for the outer layer and an outlet end that communicates with the source. The tube portion has an axis positioned at any angle ranging between the horizontal and vertical but preferably has an axis which is more vertical than horizontal. Flanges are secured to the ends of the tube portion, and the flanges are connected to an electric power supply.

Abstract: A bushing assembly for forming fibers from a supply of molten fiberizable material has: (a) a bushing block having an insulating body with a bore extending therethrough and (b) an electrically conductive bushing positioned adjacent to the bushing block to receive molten fiberizable material from the bore. The bushing includes a flange having bonded to an upper surface thereof a primary layer of an electrically insulating material with a bulk density of greater than 2.0 grams per cubic centimeter. The electrically insulating material is positioned adjacent to the liner on the lower surface of the body of the bushing block and is in contact with the molten fiberizable material.

Abstract: A flat display device, preferably of the PALC type, in which the plasma channels are formed by etching in a substrate laterally-spaced channels and bonding a thin dielectric sheet over the etched substrate. Adjoining each of the channels are shallow ledges, also formed by etching, which serve as recessed areas to receive enlarged ends serving as contact pads for each of the electrodes. Holes are formed in the thin dielectric sheet and contact material deposited on the bonded thin dielectric sheet such that the deposited material makes electrical contact with the underlying electrode contact pads and seals off the holes, which allows a plasma-forming atmosphere to be provided in the channels. This arrangement results in a glass-to-glass interface between the substrate and the thin dielectric sheet, which allows anodic bonding to be employed to assemble the two elements and thus eliminates the frit glass sealing process required in other constructions.

Abstract: A method of making core holes in cast cladding glass for fabricating optical fiber preforms to make single and multimode optical fibers. Liquid cladding glass is pored into a casting mold having a metallic wire that is translated through the liquid glass as it cools so that the wire essentially carves out a smooth cylindrical core hole along the cylindrical axis of the cooled cladding glass. The method substantially reduces surface contamination at the interface of the core hole and the cladding glass because any liquid glass that comes in contacts with the metallic wire is removed during the process, leaving behind a pristine glass surface.

Abstract: A solid workpiece, e.g. a glass tube, is shaped by a focussed beam of visible light or light in an adjacent portion of the electromagnetic spectrum in a material removal, cutting or drilling operation and is heat-treated or remelted or shaped in a plastic state by heating that second beam which is less focussed or even divergent. The beams derive from a common source, a CO.sub.2 laser, and pass through a splitting deflecting system so that the beams can be directed simultaneously either parallel to one another or with an inclination to one another at the same or different regions of the workpiece which is held in a holder capable of both rotating the workpiece and translating same.

Abstract: A method for delivering a glass stream having a first inner layer and a second outer layer, including a generally vertical orifice, and delivering glass from a second source such that the glass from the second source provides an outer layer about the glass from the first source as it flows through the orifice. A resistance heated tube assembly is made of platinum or material having similar resistance heating properties and extends from a glass source to an orifice through which the glass flows from a glass source for the inner layer. The tube assembly includes a tube portion having an inlet end that communicates with the source for the outer layer and an outlet end that communicates with the source. The tube portion has an axis positioned at any angle ranging between the horizontal and vertical but preferably has an axis which is more vertical than horizontal. Flanges are secured to the ends of the tube portion, and the flanges are connected to an electric power supply.

Abstract: A sapphire window is laser edge annealed using a CO.sub.2 laser spot illuminating along a path following the edge of the window so as to heat the edges to remove or reduce sub surface defects which can cause stress fractures.

Abstract: Converged laser beam are irradiated, at right angles, to the surface of a workpiece which is made of glass and supported in a horizontal posture, so that the surface of the workpiece is locally heated and melted. The surface of the workpiece is formed into a convexly curved surface under the effect of surface tension occurrable to the glass material at the time the surface of the workpiece is melted. By hardening the workpiece, a micro lens having the convexly curved surface is formed.

Abstract: The invention relates to a heating apparatus for a glass-sheet bending station. The apparatus includes an array of elongated heating elements, the heating elements being positioned side by side, so as to form a heating element field covering an area of a glass sheet to be bent. A control mechanism is provided for switching heating elements on and off. The heating elements are separately and independently controllable. The heating elements are positioned in succeeding heating element fields in a longitudinal direction of the heating elements. The control mechanism selectively switches on heating elements so as to form at least one heat exchange area that generally covers the area of the glass sheet being bent and that extends at a desired angle relative to the longitudinal direction of the heating elements.

Abstract: A method of processing a photosensitive glass includes exposing. Photosensitive glass by radiation from a laser whose oscillation wavelength lies within the range of wavelengths of exposing light to which the glass responds. Then, the exposed portions 1c are thermally developed and etched. Since a laser beam propagates with a high rectilinearity, the front and rear surfaces of thick photosensitive glass can be exposed without producing dimensional errors. Therefore, the etching accuracy is improved. Especially, where the front and rear surfaces of photosensitive glass are etched, both surfaces can be processed so as to form the same shape in them accurately. In addition, because almost all the energy of the laser radiation is used for exposure of the photosensitive glass, the energy is not wasted and so the efficiency is high.

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: An induction furnace for reflowing a portion of an optical preform in order to draw a lightguide fiber therefrom. The furnace has an axially located tubular iridium susceptor which is centrally disposed within a beaker and a sleeve is positioned concentrically around the susceptor. The sleeve is surrounded by an insulating grain. A high frequency coil is energized to couple its electromagnetic field to the iridium susceptor to heat and reflow a portion of the preform in order to draw the fiber therefrom. The furnace housing is sealed to provide an inert, non-oxidizing atmosphere for the iridium susceptor.

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: The invention is directed to improved centrifugal rotary electric furnaces which are used for the heating and or fusion of minerals, such as quartz, and other materials having a high melting point. The furnace includes a generally cylindrical furnace shell and a decreasing diameter stepped end member attached to each end of the shell which is intended to more closely conform the end of the furnace to the shape of fused ingot or melted charge formed inside the furnace, while still providing a sufficient depth of unmelted charge between the fused or melted material and the end member to insulate the end member from excessive heat and the warpage and other damage caused thereby.

Abstract: In the manufacture of tube glass, in which following the drawing of a tube from molten glass the inside surface of the tube is treated with a chemically reactive gas or gas mixture, a gas or gas mixture which is not reactive at the drawing temperature of the glass is dispensed into the tube in the direction of drawing. At a location in the tube where the tube has cooled down so far that the diameter is constant, the gas or gas mixture is made to react by means of a plasma which is generated in the tube.

Abstract: Disclosed is a method of producing thin films by sintering which comprises:a. coating a substrate with a thin film of an inorganic glass forming parulate material possessing the capability of being sintered, andb. irridiating said thin film of said particulate material with a laser beam of sufficient power to cause sintering of said material below the temperature of liquidus thereof.Also disclosed is the article produced by the method claimed.

Abstract: The present invention relates to a method of producing mineral wool, mineral raw material (2) is introduced into a melting unit (3), preferably a cupola furnace, for heating the mineral raw material in such a manner that molten mineral material (4) is formed on the bottom of the melting unit, whereafter the molten mineral material is discharged from the melting unit, heated further, and introduced along at least one tapping chute (8, 9) into a spinning machine (10) in which the mineral material is converted into fibre form.

Abstract: Layers of ceramic paint are applied to a surface of a glass sheet in a process wherein each layer of paint is dried by microwave energy before a successive layer of ceramic paint is applied thereover.

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: The present invention provides a method of controlling the temperature of a multiple segment fiber glass bushing. Sensors monitor the temperature of each individual segment and the current delivered to the bushing is adjusted so as to maintain the average bushing temperature at a predetermined value. In addition, the temperature of each individual segment is compared to a set point reference value and bushing current is shunted around each segment based on this comparison.

Abstract: A method of melting materials at power densities in excess of 25 KW/ft.sup.2 of area within the metal shell of a melting vessel which method consists essentially of continuously feeding the material to be melted to a plasma arc furnace which is equipped with at least two transferred arc plasma electrodes and with means to rotate at least the portion of the furnace containing the material to be melted, melting the said feedstock material using the at least two transferred arc plasma electrodes whilst rotating at least the rotatable portion of the furnace containing the material to be melted and continuously discharging the material which has been melted from the furnace.Apparatus for melting materials under power densities of greater than 25 KW/ft.sup.2 is also disclosed.

Abstract: This invention relates to a mold carriage for carrying thereon a mold for bending a glass sheet, or a stack of glass sheets to be laminated, placed thereon into a curved shape by heating in a furnace. To locally intensely heat the glass sheet in a selected area to be bent sharply relative to the major area, the mold carriage is installed with a heater to heat a selected area of the glass sheet from underneath, a holder to hold the heater and adjust the position of the heater, and a heater support to support thereon an external heater which is suspended from a separate member disposed in the furnace to heat the afore-mentioned area of the glass sheet from above. The heater support also can adjust the position of the external heater.

Abstract: An apparatus and method which provides for controlled melting of both components of coal-ash, as well as the melting of selected additives, the melted coal-ash with additive being immediately available to a conventional fiberizing spinner stage. An arc furnace provides a shallow vat for molten pig iron. A first chute allows for introduction of coal-ash into the vat, and a second chute allows for the introduction of selected additives into the vat. The molten pig iron quickly melts any coal-ash and additive entering the vat, and the molten coal-ash/additive thereupon spreads out across the surface of the molten pig iron (the molten pig iron having a much higher specific gravity). In order to ensure that the molten coal-ash/additive has a predetermined fluidity at an adjacent spinner stage, the furnace is provided with a specially structured spout located above the spinner stage.

Abstract: A fiber glass production bushing is described utilizing a flat precious metal plate which is preferably supported by a nonprecious metal support plate. The support plate has slots cut in it so that the rows of depending fiber glass tips can project through it and yet be electrically isolated from the support plate by an air gap. The side and end walls of the bushing are provided by the bushing block located above the tip plate.

Abstract: An improved bushing controller is shown which utilizes an auxiliary transformer in each of the variable impedance circuits in the controller and the bushing tha the controller is connected to increase the current capability of the controller by a significant percentage. Improved performance of fiber glass bushings producing multiple forming packages is realized.

Abstract: A vertical glass melting furnace provided with a material entrance at the uppermost portion and a molten glass exit provided at the lowermost portion. A resistance heating element 6 is provided over the substantially entire part of the horizontal section of the furnace at at least one level which is immersed in the molten glass.

Abstract: A method for the continuous production of a tube or rod of vitreous fused silica. Silicon dioxide in particle form is heated in a crucible to the softening temperature and is withdrawn contiuously downward from a bottom outlet opening in which a shaping tool is disposed. In the annular space between the shaping tool and the bottom outlet opening the softened silicon dioxide is subjected to an electrical field. In the closed crucible, a hydrogen-containing atmosphere with a hydrogen content of at least 80% is sustained above the silicon dioxide and in the space underneath the crucible that adjoins the shaping region.

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

Abstract: A 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: A lightweight, precious metal containing, glass fiberizing bushing having a novel power terminal ear arrangement is disclosed. The novel terminal ear arrangement has two relatively thin ears which extend from an area located near the midpoint of each end wall of the bushing, their elongated bases lying generally in the same plane and being generally parallel to the bottom wall of the bushing. The thin ears are spaced a relatively great distance apart but yet are relatively wide. This arrangement minimizes precious metal usage but still provides uniform heating of the molten glass within the bushing.

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: A method of, and apparatus for, repairing mechanical and/or chemical damage to the surface of glass bottles destined for re-use. A bottle to be repaired is brought to a temperature in the region of the transformation point of the glass of the bottle, its surface is thermally treated with laser beams, and during the treatment the bottle surface is linearly scanned with the laser beams while rotating the bottle about its longitudinal axis to repair the surface. The apparatus comprises a laser source and optical means for directing the laser beam generated by the laser source onto the surface of a bottle being treated.

Abstract: A nonprecious metal drain bushing for use in the start-up of a glass melting furnace. The bottom wall of the bushing is relatively wide and thick and is bent downwardly near the ends of the bottom wall to form integral terminal ears. The end portions of the terminal ears are of reduced thickness for attachment by the power clamp. The side walls coverage at an angle down to the bottom wall to facilitate flow of the molten glass through the bushing, and the thickness of the bottom wall and terminal ears is substantially greater than the thickness of the side and end walls.

Abstract: Device for continuous manufacture of fined glass in which the flow of molten material is transferred from a melting compartment (1) to a fining compartment (2) by a submerged throat (8), the fining compartment (2) comprising a chute (14) carrying the material, in an overall ascending current, and delivering it to the conditioning station (3), in a surface current, heating means (16-19) distributed in the chute (14) bringing the material to the usual debubbling temperature.This device is advantageously combined with a cupola type electric melting furnace, particularly for producing glasses with very volatile ingredients.

Abstract: A refractory metal substrate suitable for use in contact with molten glass is coated with a chromium oxide outer coating and a molybdenum disilicide buffer coating to protect the substrate from oxidation at elevated temperatures, particularly during start up of an electric furnace.

Abstract: A method of manufacturing practically stria-free, bubble-free, and homogeneous quartz-glass plates of any desired configuration and with a surface area that exceeds the cross-section of the full circular quartz-glass cylinder that is employed as a starting material. The cylinder is continuously lowered into a furnace shell flooded with an inert gas, in which it is heated to a flowing temperature in the range of 1700.degree. to 1900.degree. C. until some of the quartz-glass flows off into a graphite crucible. The crucible is preferably clad with zirconium-oxide.

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 non-precious metal drain bushing for use in the start-up of a glass melting furnace. Relatively thin, wide terminal ears extend outwardly and downwardly from the ends of the bushing and are supported against bending stresses by a rigid band or strip which contacts the outer surface of the ears and extends along the bottom wall of the bushing toward the other end for a substantial distance. In addition to the physical reinforcement it provides, the strip also acts to electrically widen the terminal ears.

Abstract: The novel inductor is used in a glass fiber manufacturing equipment comprising a centrifuge heated by a main gas heating device and a complementary induction heating device. The efficiency of the inductor is increased by a magnetic flow guiding element disposed between the inductor and the main heating device. The invention is particularly adapted to be used in the manufacture of glass wool.

Abstract: A method of manufacturing practically stria-free, bubble-free, and homogeneous quartz-glass plates of any desired configuration and with a surface area that exceeds the cross-section of the full circular quartz-glass cylinder that is employed as a starting material. The cylinder is continuously lowered into a furnace shell flooded with an inert gas, in which it is heated to a flowing temperature in the range of 1700.degree. to 1900.degree. C. until some of the quartz-glass flows off into a graphite crucible. The crucible is preferably clad with zirconium-oxide.

Abstract: A method of forming a sealed capsule containing a submilligram quantity of mercury or the like, the capsule being constructed from a hollow glass tube, by placing a globule or droplet of the mercury in the tube. The tube is then evacuated and sealed and is subsequently heated so as to vaporize the mercury and fill the tube therewith. The tube is then separated into separate sealed capsules by heating spaced locations along the tube with a coiled heating wire means to cause collapse spaced locations therealong and thus enable separation of the tube into said capsules.

Abstract: A bushing controller circuit for regulating the current flow through a fiber glass bushing to thereby control the temperature of the molten glass being drawn into fibers is disclosed. The bushing temperature is measured by a plurality of thermocouples which produce an average temperature reading that is used to control the power fed to the bushing. The bushing controller circuit is a three-terminal device connected across two sections of the bushing to regulate relative current flow in the two sections, in order to control the amount of fiber produced by each section. The bushing controller circuit includes a pair of timing circuits which operate in response to the polarity and magnitude of a control signal, produced at a remote control panel, to control the conductivity of a corresponding pair of current control devices connected across respective sections of the bushing. A reset circuit produces a signal corresponding to the zero crossing of the input AC power to synchronize the timing circuits.

Abstract: A flat plate bushing is described which eliminates extensive precious metal use in drain and/or production bushings. The bushing utilizes a novel arrangement of insulation members and support plates that allow the bushing to be electrically heated and a novel method of connecting the bushing to a power source using the bushing face plate as the connection point is also shown.

Abstract: The present invention is an auxiliary heated bushing block for a fiber forming furnace. The bushing block fits below an opening in the bottom of a forehearth of a glass melting furnace. A non-circular opening through the bushing block allows molten material to flow into a fiber forming bushing. Electrical resistance heater elements protrude through the ends of the bushing block into the non-circular opening into contact with the molten material. Each electrical resistance heater element has associated with it a separate adjustable power supply to provide individually variable power to each electrical resistance heater element. By varying the power settings of each power supply, the molten material as it flows through the non-circular opening of the bushing block can be selectively thermally conditioned.

Abstract: A laminated article for use in high temperature, oxidizing environments is provided wherein a refractory metal substrate is mechanically interlocked and diffusion bonded to precious metal components.