Abstract: A production method and others according to the present embodiment are provided with a structure for effectively preventing occurrence of accidental spiking during drawing of a preform. In order to control the residual He-concentration in the center part of the preform, a transparent glass rod that has a predetermined outer diameter and is already sintered but is not doped with an alkali metal yet is annealed in in the atmosphere not containing He gas for an annealing time determined by referring to result data in which the relationship between the annealing time and the residual He-concentration is previously recorded for each outer diameter. In the result data, actually measured data of the residual He-concentration in a produced optical fiber preform and the annealing time are accumulated as annealing treatment results.

Abstract: Forehearths that create a substantially homogeneous temperature to molten glass forming materials across the end position are provided. A gas cavity, a weir, a refractory block, or a heating element in the forehearth may be utilized to reduce a temperature gradient of molten glass forming materials across the end position. Reducing the temperature difference of the molten glass forming material across the end position permits for improved chemical and physical properties of the glass fibers and the end products formed from the glass fibers. In addition, a reduction in the temperature gradient across the end position produces a more homogenous glass fiber and glass product. Further, a reduction in the shear break rate occurs when the molten glass forming material has a temperature that is substantially the same across the end position, which results in a reduction in the breakage of glass fibers and an increase in manufacturing efficiency.

Abstract: A method and device for making high precision glass forms (110). A glass rod (1) is pushed into a melting tube (47) and the glass form is pulled from the chamber. Preferably, both the push rate and the pull rate are controlled. Fiber optic glass ferrules and other components manufactured by the use of this invention have precision dimensions that fall well within the tight dimensional tolerances required for ferrules and others.

Abstract: An internal combustion burner including a combustion chamber supplied with fuel and with oxidant and at least two combustion devices supplied with oxidant and with fuel. Combining two combustion devices of distinct configurations, which respectively generate two distinct types of flames with a system for cooling the walls of the burner by introducing air along the walls, makes it possible to obtain a burner that supplies a combustion gas temperature of up to 1700° C., while at the same time being easily cooled and occupying very little space so that it can, for example, be housed in an existing installation used in the manufacture of rock wool or glass wool.

Abstract: The invention relates to an installation and a method of producing a glass having a low boron content, containing alumina or zirconia, the melting of the batch materials being carried out in an end-fired furnace equipped with regenerators, most of the fossil energy being introduced by the U-flame, the oxidant and fuel for which are introduced at the upstream face of said furnace, the oxidant being air or oxygen-enriched air. The melting compartment may be followed by a unit for fiberizing the glass. The invention makes it possible to produce fibers with an excellent combustion efficiency and high productivity.

Abstract: The present invention relates to a process for the production of mineral fibers and to an apparatus which can be used in such a process. In particular, the process of the present invention comprises: providing a furnace; charging to the furnace mineral materials which comprise iron oxides; melting the charged mineral materials in a reducing atmosphere, such that there is a base zone in the furnace in which molten iron collects, and a melt pool above the base zone where mineral melt collects; removing mineral melt from the furnace and converting it to mineral fibers; and removing molten iron from the base zone. During the process, an additive is released directly into the base zone of the furnace wherein the additive comprises one or more substances selected from oxidizing agents and non-reducing gases.

Abstract: Method and device for manufacturing siliceous melts to produce light-yellow mineral wool fibres using a cupola furnace includes (a) a charge including at least two different types of briquet, wherein chemical components take into account an anticipated proportion of iron, (b) the components of Al2O3 in the briquets are a supporting structure for the melting process, (c) a plurality of high temperature gas burners for heating, an arrangement of said gas burners chosen such that the burner flames reinforce each other, (d) collecting pan flared conically downwards from a mantle of a shaft in the furnace to a floor of the furnace.

Abstract: In an apparatus for fabricating an optical fiber, the apparatus includes a drawing furnace provided with an insertion opening for receiving an optical fiber perform, a feed mechanism configured to support one end of the optical fiber preform so as to feed into the drawing furnace, a first sealing unit configured to seal a clearance gap between the optical fiber preform and the insertion opening, and a second sealing unit configured to seal a gap between the optical fiber preform and the first sealing unit when a tapered portion formed at the one end side of the optical fiber preform passes through the insertion opening. As a result, the available entirety of the optical fiber preform can be changed to an optical fiber, so that the cost for fabricating the optical fiber can be significantly reduced.

Abstract: A bushing for fiberizing molten material, such as molten glass, having a screen mounted in the bushing spaced above the tip or orifice plate with a central portion of the screen having a significantly lower percent of hole area than the percent of hole area in end portions of the screen. This bushing improves fiberizing efficiency in channel positions of a fiberizing operation. Also, such a screen can be laid on top of a conventional screen to convert a normal bushing to a channel position bushing. Methods of using these types of bushings to improve fiberization in the channel positions and for modifying conventional bushings for other uses are also disclosed.

Abstract: An inlet arrangement for inserting a preform (3?) into a furnace (1?) for drawing a fiber (2?). The furnace includes an enclosure (4?) at the top of which there are both an opening to allow insertion of a preform which moves in translation, and a preform inlet arrangement (13?). The inlet arrangement comprises both an injector (6?) situated at the level of the opening to inject inert gas around the preform and to fill the enclosure, and at least one seal (17B) fixed above the injector and designed to allow the preform to pass therethrough, with its cylindrical main body (9?) being surrounded. The inlet arrangement further comprises an airlock (13) for closing and sealing the top of the furnace, above the injector, whether a preform is present or absent, which airlock is pressurized to prevent the surrounding air entering. The rods of the equipped preforms carry respective continuity tubes (20) of the same diameter as the bodies.

Abstract: Disclosed is a system for drawing an optical fiber for controlling polarization mode dispersion. A furnace is provided for uniformly heating an optical fiber preform in the drawing system mounted to an optical fiber draw tower. The furnace comprises: (a) a main body; (b) a sub-body placed coaxially with the main body and having a diameter smaller than that of the main body; and (c) an upper gas feeding section over the main body, wherein the upper gas feeding section includes a first hollow rotary body having at least one slit in the inner surface thereof along the longitudinal direction of an optical fiber and at least one opening extended in the direction of the center, whereby a gas artificially/periodically creates non-contact polarization to the optical fiber by the first hollow rotary body. Effective non-contact control can be carried out about polarization mode dispersion of the optical fiber.

Abstract: The invention concerns a device (1) for sintering of a porous mold body (2) in a gas-tight chamber (3), with the mold body (2) hanging loose from a link chain (7) so that it can be fed continuously to a heating zone (5). In the area of the upper boiler (10), the traction direction of the link chain (7) is reversed by a deviation wheel (11). The tensile force is transmitted via a traction rope (13) that can be taken up on a take-up reel (14), such take-up reel (14) being driven by a drive (16) arranged outside the chamber (3). A drive shaft (15) for the take-up reel (14) provides for easy sealing of the duct (18) towards the chamber (3), because only a rotation and not a simultaneous axial displacement is required for the hoisting movement, and moreover, because the duct (18) is arranged at a spatial distance from the heating zone (5).

Abstract: A furnace for drawing an optical fiber provided with a muffle tube (10) and inner tubes (5,5′) connected to the upper end of the core tube, wherein a preform (1) supported by a dummy rod (2) at the upper part thereof is disposed inside the muffle tube (10) and inner tubes (5,5′) so as to be movable downward together with dummy rod (2), the preform (1) is heated and melted by a heater (11) from the outside of the muffle tube (10) and an optical fiber (1a) is pulled out from the lower end of the preform (1); the furnace is further provided with one or a plurality of sets of separating plates (4, 17) adapted to partition a space in the inner tubes (5,5′) above the preform (1) into a plurality of portions in the advance direction of the preform and disposed in the space, and with gas blowing inlets (8) disposed in the parts of wall surfaces of the inner tubes (5,5′) which are below the separating plates (4, 17) and adapted to blow an inert gas into the inner tubes (5,5′) and the muff

Abstract: A furnace for drawing an optical fiber provided with a muffle tube (10) and inner tubes (5,5′) connected to the upper end of the core tube, wherein a preform (1) supported by a dummy rod (2) at the upper part thereof is disposed inside the muffle tube (10) and inner tubes (5,5′) so as to be movable downward together with dummy rod (2), the preform (1) is heated and melted by a heater (11) from the outside of the muffle tube (10) and an optical fiber (1a) is pulled out from the lower end of the preform (1); the furnace is further provided with one or a plurality of sets of separating plates (4, 17) adapted to partition a space in the inner tubes (5, 5′) above the preform (1) into a plurality of portions in the advance direction of the preform and disposed in the space, and with gas blowing inlets (8) disposed in the parts of wall surfaces of the inner tubes (5, 5′) which are below the separating plates (4,17) and adapted to blow an inert gas into the inner tubes (5,5′) and the muf

Abstract: The invention discloses a multifunctional apparatus and method to manufacture mineral (basalt) fibers to be drawn/attenuated into a continuous strand made from natural rock basalts with and without supplemental minerals. More specifically this invention discloses apparatus designed to manufacture a high quality continuous amorphous mineral (basalt) fibers with flexible/ductile properties from 7 &mgr;m to 100 &mgr;m in diameter without traces of crystalline phases which are suitable for a variety of industrial applications.

Abstract: A furnace for drawing an optical fiber provided with a muffle tube (10) and inner tubes (5, 5′) connected to the upper end of the core tube, wherein a preform (1) supported by a dummy rod (2) at the upper part thereof is disposed inside the muffle tube (10) and inner tubes (5, 5′) so as to be movable downward together with dummy rod (2), the preform (1) is heated and melted by a heater (11) from the outside of the muffle tube (10) and an optical fiber (1a) is pulled out from the lower end of the preform (1); the furnace is further provided with one or a plurality of sets of separating plates (4, 17) adapted to partition a space in the inner tubes (5, 5′) above the preform (1) into a plurality of portions in the advance direction of the preform and disposed in the space, and with gas blowing inlets (8) disposed in the parts of wall surfaces of the inner tubes (5, 5′) which are below the separating plates (4, 17) and adapted to blow an inert gas into the inner tubes (5, 5′) and the

Abstract: The glass base material drawing apparatus for heating and drawing a glass base material has a storage unit for storing the glass base material having an opening unit that is opened along the longitudinal direction of the storage unit when the glass base material is placed inside the storage unit, a heating unit for heating the glass base material that has been stored inside the storage unit via the opening unit, and a pull-out unit for pulling out the glass base material heated by the heating unit. The opening unit may be opened in such a manner that the glass base material is moved from a side direction of the storage unit into the interior of the storage unit. A main axis for supporting the glass base material is connected to the glass base material. The storage unit may have a penetration hole through which the main axis is inserted when the opening unit is closed.

Abstract: An optical fiber preform suspending and supporting apparatus able to prevent deformation of a pin placed in a high temperature environment and able to support a porous optical fiber preform without adversely influencing supports of the pin and without causing inclination relative to the vertical line of a main shaft, wherein a movable connector is fitted into an enlarged-diameter portion of the lower end of a main shaft, this enlarged-diameter portion is connected with the movable connector by a pin so that the movable connector is able to swing around the pin, a holding portion including a supporting portion is formed integrally at the bottom of the movable connector to hold an enlarged-diameter portion of the upper end of a starting preform, and the diameter of the pin is in the range of 20% to 50% of the outside diameter of the enlarged-diameter portion of the lower end of the main shaft, and an optical fiber processing apparatus including the same.

Abstract: The invention concerns a device (1) for sintering of a porous mold body (2) in a gas-tight chamber (3), with the mold body (2) hanging loose from a link chain (7) so that it can be fed continuously to a heating zone (5). In the area of the upper boiler (10), the traction direction of the link chain (7) is reversed by a deviation wheel (11). The tensile force is transmitted via a traction rope (13) that can be taken up on a take-up reel (14), such take-up reel (14) being driven by a drive (16) arranged outside the chamber (3). A drive shaft (15) for the take-up reel (14) provides for easy sealing of the duct (18) towards the chamber (3), because only a rotation and not a simultaneous axial displacement is required for the hoisting movement, and moreover, because the duct (18) is arranged at a spatial distance from the heating zone (5).

Abstract: An inlet arrangement for inserting a preform (3′) into a furnace (1′) for drawing a fiber (2′). The furnace includes an enclosure (4′) at the top of which there are both an opening to allow insertion of a preform which moves in translation, and a preform inlet arrangement (13′). The inlet arrangement comprises both an injector (6′) situated at the level of the opening to inject inert gas around the preform and to fill the enclosure, and at least one seal (17B) fixed above the injector and designed to allow the preform to pass therethrough, with its cylindrical main body (9′) being surrounded. The inlet arrangement further comprises an airlock (13) for closing and sealing the top of the furnace, above the injector, whether a preform is present or absent, which airlock is pressurized to prevent the surrounding air entering. The rods of the equipped preforms carry respective continuity tubes (20) of the same diameter as the bodies.

Abstract: An apparatus and method for sealing the top of an optical waveguide draw furnace is disclosed. The apparatus includes an assembly constructed and arranged to removably cover the top of the draw furnace while mating with the downfeed handle. The apparatus includes an elongated sleeve having a base and a sealing mechanism positioned on the sleeve at a location remote from the base. The sleeve defines a chamber for receiving the downfeed handle, and the sealing mechanism is arranged with respect to the sleeve to mate with the downfeed handle received in the chamber. In one aspect of the invention, the apparatus further includes an inert gas purge for providing an inert atmosphere within the chamber. A method of sealing the top of an optical waveguide draw furnace is also disclosed.

Abstract: An optical fiber preform suspending and supporting apparatus able to prevent deformation of a pin placed in a high temperature environment and able to support a porous optical fiber preform without adversely influencing supports of the pin and without causing inclination relative to the vertical line of a main shaft, wherein a movable connector is fitted into an enlarged-diameter portion of the lower end of a main shaft, this enlarged-diameter portion is connected with the movable connector by a pin so that the movable connector is able to swing around the pin, a holding portion including a supporting portion is formed integrally at the bottom of the movable connector to hold an enlarged-diameter portion of the upper end of a starting preform, and the diameter of the pin is in the range of 20% to 50% of the outside diameter of the enlarged-diameter portion of the lower end of the main shaft, and an optical fiber processing apparatus including the same.

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 furnace minimizes the lowering of the quality of optical fibers, especially those lowerings of the quality that stems from variations of the conditions inside of the furnace. These variations can occur when a preform is connected to an auxiliary quartz rod of differing diameters. Also, the furnace has an inlet sleeve which minimizes fluctuations in flow speed of the inert gases and the pressures inside the furnace.

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: The present invention provides a system for producing glass fiber product from scrap glass fibers comprising at least one crusher having at least one pair of rotatable rollers which rotate at essentially the same speed, the rollers having intermeshing protuberances for crushing scrap glass fibers passing therebetween; a dryer for drying the crushed glass fibers to form dried glass fibers having a mean average moisture content of less than about one weight percent; and a separating device for separating the crushed glass fibers into (1) a first portion of crushed glass fibers having a mean average length of less than about 5 millimeters and (2) oversize dried waste material.

Abstract: An electric open-top melter for use in the manufacture of mineral fibers, such as fiberglass, is provided with a side-discharge outlet. The side-discharge outlet allows the melter, conditioner/refiner, and forehearth to all be located on substantially the same level, thereby allowing molten glass to flow from the side of the melter, through the conditioning zone, and into the forehearth from which spinners produce glass fibers or the like. Isolation members are provided in the conditioning or refining area so as to enable molten glass therein to be isolated from the melter and forehearth when the molten glass level is lowered below the tops the isolation members.

Abstract: A device for drawing down an optical fiber preform (2) connected at one end to a feed rod (3) having an equal or smaller diameter. A chamber (11) in which the preform is drawn has an upper part (11A) with an opening (12). The opening engages the preform to seal the chamber. An enclosure (5) has a seal (6) at its upper part (5A) for sealing around the feed rod. A lower part (5B) of the enclosure contacts the upper part of the chamber to seal the chamber while the feed rod is passing through the opening.

Abstract: A process and apparatus are described for forming glass fibers which utilizes a rotating melter for the fiber glass batch materials and stators which house the fiber forming bushings. The stators are encompassed by the rotating melter, but not physically touching it. The glass melt flows directly from the melter to the bushings in the stators and temperatures at the bushings are controlled by raising or lowering the stator with respect to the melter, the bushings being devoid of any electrical energy input as is conventionally practiced.

Abstract: An induction-heated furnace, suitable for heat treatment of synthetic silica bodies, under conditions of high purity, includes a tubular susceptor (1) disposed with its axis vertical and an induction coil (3) for raising the temperature of the susceptor. The susceptor is made from graphite and/or silicon carbide, and is enclosed within a vacuum envelope (2) made from vitreous silica or fused quartz, the envelope being surrounded by the induction coil which is liquid-cooled. The design is such that the vacuum envelope (2) operates at temperatures below those at which either devitrification or sagging of the envelope might occur even when the tubular susceptor (1) is heated to a temperature of 1700.degree. C. Thus sintering of a porous synthetic silica body (9) can be carried out under atmospheric or reduced pressure, the furnace including a shaft (7) adapted to support the body to be heated and capable of rotation about and movement along said vertical axis of the tubular susceptor (1).

Abstract: The melting tub for producing the molten mass from a mixture of raw material is associated with an additional melting unit by means of which a recycled molten mass is obtained from mineral wool waste largely corresponding to the molten mass obtained from the mixture of raw materials in quality and composition. The recycled molten mass is supplied to the molten mass in the melting tub through a suitable introduction device. The recycling exhaust gas from the additional melting unit is fed to the tub exhaust gas, and the mixture of exhaust gas is utilised for pre-heating combustion air and mixture of raw materials.