Abstract: A raw material supplying device having a gas tight tank for receiving a material to be gasified by heating; a heater for heating the raw material within the tank and a plurality of pipes for conveying a plurality of streams of gas in parallel to each other to a plurality of ports of a reaction apparatus, and a process for using the raw material supplying device. The raw material supplying device can be used in a system for manufacturing glass fibers in which the ends of the plurality of pipes are connected to the gas feed ports of at least one multi-layer burner.

Abstract: An improved method for fabricating an optical fiber preform by the vapor phase axial deposition (VAD) method, comprises forming core and cladding soots at the same time by the use of core and cladding burners. The improvement is that the cladding burner is designed so that at least one of the outlets for a feed material gas, a fuel gas, an auxiliary fuel gas, and an inert gas is composed of a plurality of openings. In this improved method, the temperature distribution from the boundary of the core soot to the periphery of the cladding soot is made smooth, and thus the cladding soot is prevented from cracking.

Abstract: For the continuous casting of silicon, an electrically conductive bottomless crucible is circumferentially divided by axial slits and is positioned within an electrical induction coil. The slits form circumferential gaps of between 0.3 mm and 1.0 mm and the inner wall of the crucible is inclined by between 0.4.degree. and 2.0.degree., so that the crucible expands in the downstream direction of movement of the silicon. In order to reduce the temperature gradient of the solidified silicon to between 20.degree. C./cm and 100.degree. C./cm, an additional heating element is disposed downstream of the boundary surface between the molten and solidified silicon. The crucible may be cooled by forming the crucible as a double walled cylinder and flowing a coolant therethrough.

Abstract: A method for consolidating a porous glass preform is provided in which a preform is placed in a stationary elongated chamber and selected portions of the chamber, distributed along the chamber's length, are sequentially heated above the preform's sintering temperature. In certain preferred embodiments, the chamber is surrounded by an elongated susceptor and the heating is performed by moving an induction heating coil along a path parallel to the longitudinal axes of the susceptor and the chamber.

Abstract: A heating oven is provided for processing glass materials, e.g., porous glass preforms, from which optical waveguide fibers are prepared. The oven includes a stationary elongated chamber, e.g., a silica muffle, for receiving the glass material which is to be processed. At least a portion of the chamber is surrounded by a stationary susceptor. The chamber is heated by moving an energized induction heating coil along a path parallel to the longitudinal axes of the susceptor and the chamber.

Abstract: A method of manufacturing a blank for a light-weight mirror. Graphite molding bodies are positioned at regular intervals on a base that functions as a mirror plate or backing plate. The base is surrounded up to the top of the molding bodies with a graphite wall. The interstices between the molding bodies and between the wall and the molding bodies are filled with granular quartz. The assembly is heated in an evacuated furnace to approximately 1730.degree. C. into a honeycomb-shaped supporting structure that is securely fastened to the base. The graphite molding bodies and wall are removed after cooling. Either a backing plate or a mirror plate in the form of another plate is applied to the resulting supporting structure.

Abstract: A spherulizing furnace for manufacturing vitreous beads, including a chamber; means for heating the chamber; feed means for delivering a particulate feedstock to one end of the chamber; and means for collecting vitreous beads from another end of the chamber, wherein the chamber includes a pair of opposed walls which are spaced apart by a distance less than their breadth and which are angled to the horizontal so that the chamber has an upper end and a lower end, the feed means is arranged to deliver feedstock to the upper end of the chamber so that the feedstock can pass through the chamber under gravity, and the means for heating the chamber is arranged to heat at least one wall of the pair of opposed walls so that feedstock passing between the pair of opposed walls is heated by radiant heat.

Abstract: Porous bodies of a material comprising SiO.sub.2 as the main constituent are heated by passing a zone of high temperature through the body. This high temperature zone is obtained by irradiation with light of a wavelength which is obsorbed by the porous part of the body, but which is not absorbed by the densified part of the body. The device preferaby comprises a rotatable radiation source surrounding the body to be densified.

Abstract: A burner for producing glass fine particles provided with an intermediate passage between a central passage and an outer passage for surrounding the periphery of the central passage characterized by that the end of the intermediate passage is disposed inner side from the end of the outer passage and the end of the central passage is disposed between the end of the intermediate passage and the end of the outer passage. Thus, the burner can stably fabricate porous glass base material having GI type or triangular refractive index distribution and yet can suppress the production of bubbles.

Abstract: An apparatus for fabricating an optical fiber preform having a support for rotatably holding a reaction tube, a raw material supply unit for supplying a glass raw material from one end of the reaction tube to the interior of the reaction tube and a heater for heating the reaction tube by reciprocating in the axial direction of the reaction tube which comprises a pressure measuring unit at the other end of the reaction tube, a gas pressure control chamber having a gas inlet and an exhaust port, and a blower capable of controlling the introduced gas pressure according to the measured value of the pressure memasuring unit in the gas inlet. Thus, the apparatus can accurately control the internal pressure of a reaction tube in good responsiveness.

Abstract: In an optical fiber preform fabrication method having the steps of decomposing a glass raw material in a flame so that fine glass particles are produced; depositing the fine glass particles on a seed rod to form a porous preform; and consolidating the porous preform into a transparent optical fiber preform, use is made of a burner having a raw material supply orifice for supplying the glass raw material and a plurality of flame forming orifices deposed around the raw material supply orifice sequentially for forming a plurality of flames, respectively. The flame speed V.sub.k of a kth flame, the flame speed V.sub.k+1 of a (k+1)th flame surrounding outwardly of the kth flame and the flow speed Vm of the glass raw material are determined in a suitable manner. The glass raw material is supplied to the multi-flame produced by the burner in which the kth flame is positioned rearwardly of the (k+1)th flame to synthesize the fine glass particles.

Abstract: In the P.C.V.D. process in principal the quartz tube need not be rotated during the deposition of the glass layers. However it has been found in practice that an improvement in the quality of the glass fibers can be obtained if the quartz tube is rotated regularly over an angle of 360.degree./n. n is preferably equal to an integer from 2 to 12.

Abstract: A heating oven for processing glass materials from which optical waveguide fibers are prepared is provided which comprises:(a) an elongated chamber for receiving the glass material to be processed; and(b) means for heating the chamber, said means comprising an elongated susceptor, the longitudinal axis of the susceptor being parallel to the longitudinal axis of the chamber, an induction heating coil, means for moving the induction heating coil along a path parallel to the longitudinal axes of the susceptor and the chamber, and means for energizing the induction heating coil.

Abstract: In an apparatus for the production of a porous optical fiber preform in a reaction container is provided in which a bar like starting member is movably supported for rotating and reciprocally moving across a gas flow, and a burner is provided for generating glass particles. An opening is provided on one side of the reaction container for introducing a gas flow and another opening is located on the other side of the reaction container opposite to the first mentioned opening, so that the gas flow is rectified in the reaction container and the glass particles can be deposited on the starting member with a uniform density distribution.

Abstract: A porous glass optical waveguide preform is formed by depositing a coating of glass particulate material on the lateral surface of a core which may be a porous glass body continuously produced by the axial deposition of glass particles. The core rotates and moves longitudinally in one direction with respect to two flame hydrolysis burners which emit streams of glass particles having different compositions. In addition, the two burners reciprocatingly move with respect to a portion of the length of the core. The speed of each burner varies as it traverses along its path of reciprocating motion. The thickness of the layer produced by a burner at a given point is inversely related to the speed of the burner as it passes that point. The layers formed by the completion of a single traverse by both burners combine to form a conically-shaped layer, the composition of which varies from the base toward the apex thereof.

Abstract: A porous glass optical waveguide preform is formed by depositing a coating of glass particulate material on the lateral surface of a core which may be a porous glass body continuously produced by the axial deposition of glass particles. The core rotates and moves longitudinally in one direction with respect to two flame hydrolysis burners which emit streams of glass particles having different compositions. In addition, the two burners reciprocatingly move with respect to a portion of the length of the core. The speed of each burner varies as it traverses along its path of reciprocating motion. The thickness of the layer produced by a burner at a given point is inversely related to the speed of the burner as it passes that point. The layers formed by the completion of a single traverse by both burners combine to form a conically-shaped layer, the composition of which varies from the base toward the apex thereof.

Abstract: An apparatus is provided for the production of a porous preform of SiO.sub.2 used in the manufacture of optical fiber wherein damage to the preform caused by falling clusters of SiO.sub.2 or GeO.sub.2 formed on the wall of the deposition chamber is eliminated. In accordance with the invention, a conductive shielding member is provided inside the wall defining the deposition chamber. This shielding member eliminates an electrostatic field produced on the wall by charging, therefore preventing the adherence of fine particles thereto.

Abstract: A flat-bottomed quartz glass crucible for the manufacture of monocrystalline silicon is made by disposing granular quartz particles on a flat base in a cylindrical mold. A vacuum is drawn on the particles through vacuum holes in the base to retain the particles thereon while the base and mold are rotated, and while the particles are heated to fuse them into a quartz glass crucible shape.

Abstract: A method of fabricating a porous glass rod having a reaction vessel including an elevational passage from an exhaust port of the vessel side and the top of the vessel over the interior and a burner mounted at the end in the vessel for forming glass fine particles, and a target elevationally movable and rotatably inserted from the passage into the vessel which has injecting to accumulate glass fine particles produced through the burner to form the porous glass rod at the lower end of the target rotated at a predetermined position in the reactor, and drawing the target in response to the growing velocity of the porous glass rod, wherein downward gas stream is produced along the outer periphery of the conduit in the vessel. The method is conducted by an apparatus for fabricating the glass rod. The method and apparatus can stabilize the fluidity in a reaction vessel to stabilize the outer diameter and the refractive index distribution of the glass rod in the longitudinal direction.

Abstract: An exhaust system (3) for a vapor-phase axial deposition (VAD) system (5) is comprised of the serial combination of an exhaust tube (26), an outlet pipe (27), a soot collection chamber (32) and a discharge line (34). The exhaust tube (26) has a constricted central portion (48) and a flared intake (44) with a gradually turned back end (46).

Abstract: A vapor-phase axial deposition system (5) for fabricating a lightguide soot boule (16). The system (5) is comprised of a short cylindrical housing (10) having end plates (26--26) affixed thereto. A starting member (58) is radially directed into the central portion of the housing (10) and a torch (12) is activated to direct a stream of glassy soot thereat. The member (58) is simultaneously rotated and withdrawn from the housing (10) as a cylindrical, porous, soot boule is formed on the end thereof. The housing (10) having a substantially two-dimensional character eliminates secondary gas flow within the housing (10) resulting in enhanced deposition rates and repeatability.

Abstract: To make quartz glass crucibles suitable for drawing of single crystal silicon for electronic semiconductor applications, granular crystalline quartz or amorphous quartz glass is introduced into a rotating hollow mold which has gas-pervious wall regions at the side walls and bottom thereof, for example by having bores extending through a metal mold or being made of porous, sintered material. After introducing the raw material, a heat source, such as an electric arc, is introduced into the hollow mold, causing first sintering and then melting of an inner layer; upon introduction of the hollow mold, a vacuum is applied to the outside of the hollow mold, for example between the housing and the mold body, and, during continued rotation, to draw out any included gases and cause melting-together of vacuoles which, otherwise, might form due to included spaces and gases within the granular filling material.

Abstract: A core torch for fabricating a single-mode optical fiber preform wherein fine glass particles are produced eccentrically with respect to the center area of a flame stream, the core torch being so arranged as to blow the flame stream at an angle inclined to a seed rod. The porous glass body forming the core is grown on one end of the rod and in the direction of the axis of the rod. A cladding layer is formed on the periphery of the porous glass core body by at least one torch for forming the cladding. The obtained porous glass body is heated and vitrified into a transparent glass body, which is sealed in a silica tube for jacketting to form a single-mode optical fiber preform. At least one exhaust port is disposed within a distance of 1 mm to 50 mm from the periphery of the porous glass body and in the vicinity of the growing surface of the glass body to exhaust residual glass fine particles and undesired gases. A porous glass body having a diameter of 20 mm or less is easily formed.

Abstract: Disclosed are a method and apparatus for forming a continuous length of glass article. A coating of glass particles is deposited on a mandrel having a thermal coefficient of expansion much greater than that of the glass particles. The mandrel is allowed to cool, thereby causing it to shrink and separate from the coating. The coating is indexed a discrete longitudinal distance along the mandrel, thereby uncovering a region of the mandrel. Another coating of glass particles is deposited on the uncovered region of the mandrel and over a portion of the previously applied coating. The steps of separating or freeing the coating from the mandrel, longitudinally indexing the coating with respect to the mandrel and depositing another coating are repeated. Thus, each step of indexing longitudinally translates an incremental length of a porous body from the end of the mandrel.

Abstract: A porous glass optical waveguide preform is formed by depositing a coating of glass particulate material on the lateral surface of a core which may be a porous glass body produced by the axial deposition of glass particulate material. The core rotates and moves longitudinally in one direction with respect to a flame hydrolysis burner. In addition, the burner oscillates longitudinally with respect to a portion of the length of the core.

Abstract: A glass optical waveguide preform is prepared by chemical reaction of vapor ingredients within a bait tube. As the reactants flow through the bait tube, a hot zone traverses the tube to cause the deposition of soot in a section of the tube downstream of the hot zone. An axially disposed heater enhances the thermophoresis effect within the tube, thereby increasing deposition rate and efficiency.

Abstract: A glass optical fiber waveguide preform is prepared by chemical reaction of vapor ingredients within a bait tube. As the reactants flow through the bait tube, a hot zone traverses the tube to cause the deposition of soot in a section of the tube just downstream of the hot zone. An axially disposed heater, which is located just downstream from the hot zone in the vicinity of the soot deposit, is mechanically coupled to the burner which generates the hot zone. The heater enhances the thermophoresis effect, thereby increasing deposition rate and efficiency. Also, a gas may be flowed over the surface of the heater to confine the reactant vapors to an annular channel adjacent the bait tube wall and to prevent soot deposition on the heater. The heater may comprise an enlarged end portion to cause soot to flow toward the bait tube wall in the deposition region.

Abstract: A lightguide starting tube or rod (12) passes through opposed lateral openings (51--51) in a chamber (31) which contains an oxy-hydrogen torch (14) used to deposit particulate glass on the rod. Frusto-conical, laminar flow, gas shields (71 and 72) are formed about the rod (12) on both sides of said openings (51--51) to permit the rod to pass therethrough in spaced relation to the openings while sealing said openings to prevent gas or undeposited particulate from passing therethrough and preventing contaminants from entering the chamber (31).

Abstract: A method for the production of a preform with a view to obtain an optical fibre with index jump or gradient, consisting in spreading over a substrate, a solution of doped transparent substance, the said substrate being simultaneously driven in rotation about its axis and heated; the solution is spread over successive parts of the substrate, and each part starts being heated when the solution is being spread thereon.The present invention finds an application in the production of silica preforms.

Abstract: A glass optical waveguide preform is prepared by chemical reaction of vapor ingredients within a bait tube. As the reactants flow through the bait tube, a hot zone traverses the tube to cause the deposition of soot in a section of the tube just downstream of the hot zone. An axially disposed tubular burner, which is located just upstream from the hot zone, is mechanically coupled to the burner which generates the hot zone. The burner generates an axial water-free flame that extends through the hot zone. The flame creates a mandrel which confines the flow of reactants to an annular channel adjacent the bait tube wall in the hot zone. The flame also extends downstream from the hot zone where it increases the thermal gradient between the axis and the wall of the bait tube, thereby enhancing the thermophoresis effect, whereby deposition rate and efficiency are improved.

Abstract: A substantially continuous method of and apparatus for forming an article suitable for an optical waveguide preform wherein the starting member is continuously removed is disclosed. The preform is formed by providing a starting member or bait and applying the particulate material to the exterior surface of the starting member to form a coating thereon. The coating is longitudinally translated while simultaneously additional particulate material is applied to the coating to form a preform body with the preform body thereafter being longitudinally translated. While longitudinally translating the preform body and applying additional particulate material to the end thereof, the starting member is continuously removed from the preform body leaving a longitudinal aperture remaining in the preform body. The particulate material may be applied by one or more burners, the output of which may be controlled to provide a predetermined desired cross sectional composition variation of the resulting preform body.

Abstract: Apparatus and process for automatic control of the production of optical fiber are disclosed. The process comprises continuously depositing and sintering borosilicate glass particles on a fused silica rod or a graded index rod in such a manner that the glass exhibits a uniform, radially increasing concentration of boron. The appropriate boron oxide/silica concentration ratio in the glass particles is controlled by the time of deposit and the weight and diameter of the rod, which are continuously monitored. The concentration of boron oxide and silica in the particulate is likewise continuously monitored to insure that the correct portion of boron oxide/silica is deposited.The apparatus for conducting the process, includes means for continuously monitoring the weight and diameter of the rod and the boron oxide content of the glass particles and means for automatically regulating the equipment used to produce the optical fiber in response to readings from the monitoring means.

Abstract: An apparatus for producing a continuous strip of foamed ceramic or glass comprises a tubular furnace traversed by a plurality of molds suspended from respective trolleys or carriages and disposed in end-to-end relationship within the furnace. The molds are swung open after cooling and separated from one another as they leave the strip by being elevated at a downstream portion of the mold path.

Abstract: An article suitable as an integral handle for an optical waveguide preform is disclosed. The article comprises a hollow tubular member defining a substantially longitudinal aperture and having one end thereof tapered and of diminishing wall thickness for the length of said taper. Adjacent the tapered end is disposed an outwardly extending protrusion which is embedded in one end of an optical waveguide preform forming an integral unit therewith. Means are provided for a substantially gas-tight connection to the handle so that a gaseous medium may be flowed through the handle and the optical waveguide preform in its porous soot form. Means are also provided for attaching and securing the composite structure to a source of gaseous medium. Also disclosed is the combination of an optical waveguide preform rigidly affixed to a handle.

Abstract: A polycrystalline article is densified to provide either a nonporous body or a body with controlled interconnected porosity. A mixture of fine powders of the polycrystalline material and a sintering aid is compacted and outgassed under reduced pressure. The outgassed compact is then subjected to a permeation anneal step in which it is heated in a closed chamber to a temperature sufficient to form a liquid of the sintering aid, but under pressure conditions which inhibit evaporation of the sintering aid. The sintering aid can then be leached out to provide a densified article having interconnected porosity. Alternatively, the sintering aid can be leached out at elevated temperature, further densifying the compact to form a substantially nonporous body. Alternatively, the sintering aid can be removed by subjecting the densified article to an evaporation anneal step in which the article is heated to evaporate the sintering aid, further densifying the compact to form a substantially nonporous article.

Abstract: Methods and apparatuses are disclosed for exhausting reaction products from an optical fiber preform tube and for choking off the preform tube during collapse wherein an exhaust tube (40) is provided with an entry end (41) located adjacent and in fluid communication with a downstream end (10') of a preform tube (10), suction applied to the exhaust tube (40), and a stream of reaction product agitating gas free of reaction products introduced into the exhaust tube (40) at a location adjacent the exhaust tube entry end (41).

Abstract: A method for producing an optical fiber preform comprising the steps of blowing, through at least one nozzle, gaseous material producing glass material soot by a CVD reaction to permit the glass material soot to be deposited on a target to produce a soot rod which grows in size, and heating and rendering transparent the soot rod produced in the first step, wherein a pipe is arranged substantially concentrically with the glass material soot so as to permit gas to flow through a clearance between the deposited glass material soot and the inner wall surface of the pipe in a direction in which the soot rod grows in size. The method makes it possible to prevent the outer peripheral portion of the soot rod from becoming porous and to satisfactorily control the diameter of the soot rod.

Abstract: In making a preform for an optical waveguide, the bait rod is coated with carbon. After the preform is built up on the bait rod, it is easily removed. The carbon coating produces a smooth improved inner surface in the preform, thereby eliminating flaws which otherwise may be present when the preform is drawn into a waveguide.

Abstract: Apparatus for forming a vapor of material to be hydrolyzed and/or oxidized and entraining the vapor in a carrier gas. The source material, in liquid form, is pumped to a point in the column above a porous packing. As the liquid progresses downward through the packing, it encounters a rising countercurrent of carrier gas. The source material vaporizes and is delivered to vapor deposition by the carrier gas. The source material vaporized in the apparatus may alternatively be delivered to an externally heated tubular reactor, or to any other kind of chemical vapor deposition (CVD) reactor.

Abstract: Disclosed is a method and apparatus for forming hollow and cylindrical ingots of amorphous or fused silica and other ingot materials. The ingot is formed from a melt on a deposition surface which is lowered as the ingot is formed at a rate which maintains a constant distance between the deposition surface and a heat source vertically positioned above same. The melt is shaped into a vertical cylinder by at least one forming tool which is a roller member rotatable about a vertical axis. In a preferred embodiment the fixed distance from the heat source is maintained with the aid of the laser beam.

Abstract: An element of a dual-in-line ceramic package such as a substrate or cover provided with a layer of sealing glass is prepared by forming powdered low-melting sealing glass into a shape conforming to that of the element, compressing and sintering the shaped powdered glass to form a solid sintered sealing glass preform, applying the preform to the surface of the element, and fusing it thereto by heating the assembly.

Abstract: Disclosed is a method and apparatus for forming hollow and cylindrical ingots of amorphous or fused silica and other ingot materials. The ingot is formed from a melt on a deposition surface which is lowered as the ingot is formed at a rate which maintains a constant distance between the deposition surface and a heat source vertically positioned above same. The melt is shaped into a vertical cylinder by at least one forming tool which is a roller member rotatable about a vertical axis. In a preferred embodiment the fixed distance from the heat source is maintained with the aid of the laser beam.

Abstract: The production of shaped glass articles is undertaken by an injection moulding process by charging a particulate inorganic glass having a transformation temperature of not greater than 300.degree. C to an injection moulding machine; by converting the glass to a molten state in the barrel of the machine; and by injecting the molten glass into a mould on the machine.

Abstract: A continuous process for the manufacture of cellular ceramic product. Ceramic feed material is transported successively through a preheat kiln section, through a foaming section whereat foaming agent mixed with the ceramic feed material is activated, and into a drawing kiln section. An elongate hollow product can be formed by drawing the foamed ceramic while soft around and past a hollow mandrel to form an elongate hollow cylindrical member.