Abstract: A method for producing glass bubbles, which comprises heating a glass powder containing a gas-blowing agent in an atmosphere containing steam having a partial steam pressure of at least 0.2 atmosphere to foam it.

Abstract: An improved method for forming optical fiber preforms by the chemical vapor deposition technique utilizes an elongated burner having an array of burner orifices that forms an elongated silica particle stream having a thickness generally related to the diameter dimensions of a cylindrical preform starter rod. The burner can be formed as an elongated plate having the array of gas ports that produce the desired or silica stream. As a consequence, high initial silica particle deposition rates are obtained compared to prior methods utilizing circular burners, with the high initial deposition rates maintained throughout preform fabrication to result in an increase in preform production rates with an accompanying reduction in costs.

Abstract: A valve apparatus for the precise regulation of a stream of molten material such as molten rock or slag as it issues from a primary melter or holding device, comprising a frame retaining a valve, the valve comprising a pair of plate-form valve members, one fixed and one movable with respect to the other, each having an aperture or orifice provided therein. Maximum rate of discharge occurs when the apertures are in juxtaposition, and flow cut-off occurs when the apertures are not in juxtaposition. Power operated means is provided for the movable valve member to obtain proper stream regulation or complete cut-off. The apertures are so contoured that, as the valve is moved toward closed position, the cross-sectional shape of the effective opening and the flowing stream of molten material remains substantially uniform and unchanged.

Abstract: A powdery substance, such as for example pyrogenically prepared silicon dioxide, is subjected to predensification through the utilization of centrifugal force in a centrifuge. Subsequently, the centrifuge receptacles are closed with a free flying piston. Through utilization of the centrifugal force, there is achieved through the use of the free flying piston an additional pressure which is exerted on the predetermined powdery substance.

Abstract: A sol-gel method of preparing doped glass articles is provided. The glass is formed by preparing a sol solution containing hydrolyzed silicon alkoxide and ultrafine particle silica. The sol solution can also include a dopant. The sol solution is gelled in a container, dried and sintered to yield the doped silica glass articles.

Abstract: The present invention relates to a method of producing a fluoride glass preform and/or fiber having a modified refractive index by heating the fluoride glass preform to a temperature that is above its glass transition temperature, but below its devitrification temperature; inserting a first electrode into the inner core of the preform and surrounding the outer perimeter of the preform with a second electrode of opposite polarity; means for generating an electromotive force; and applying an electromotive force through the first electrode and the second electrode which causes a movement of positive ions toward the electrode of opposite charge while simultaneously causing a movement of negative ions toward its electrode of opposite charge such that the movement of these ions results in a modification of the refractive index of the preform.

Abstract: A method of preparing tubular silica glass is disclosed. The method includes the steps of first hydrolyzing silicon alkoxide with acid and then adding ultra-fine particle silica to form a sol solution. The sol solution is placed in a cylindrical container and gelled while rotating the cylindrical container to obtain a tubular gel. The tubular gel is dried and sintered to the tubular silica glass.

Abstract: A method of preparing preforms for optical fibers is provided. The method includes preparation of a first sol solution of a silicon alkoxide hydrolyzed with an acid and ultrafine particle silica, placement of the first sol solution into a container, and gelation of the first sol solution while the container is being rotated to yield a wet gel having a center hole. A second sol solution having a different composition than the first sol solution is prepared and used to fill the center hole in the wet gel. The second sol solution is then gelled to a wet gel composite and the composite is dried and sintered to yield the preform.

Abstract: Waste asbestos is converted into a glass by maintaining within an electrical glass melting furnace a body of molten glass at a temperature above the decomposition temperature of asbestos; supplying asbestos to the furnace; and withdrawing molten glass from the furnace at a temperature of at least 1000.degree. C. The asbestos is advantageously mixed with cullet and a melt accelerator and fed into the furnace by means of a screw mixer/conveyor. The furnace is advantageously operated at a pressure less than atmospheric pressure.

Abstract: An annular blower which has an internal baffle. The blower is used to attenuate glass fibers centrifuged from a spinner in a rotary fiberizer process. The internal baffle directs and uniforms gas flow in the blower and decreases turbulent flow conditions in the gas flowing from the periphery of the blower.

Abstract: Disclosed is a method for the axial building up, in a vertical arrangement, of a hollow cylindrical soot body having no internal support and consisting substantially of silicon dioxide by means of at least one flame hydrolysis build-up burner serving for the soot production. In this method the soot is deposited at the beginning of the build-up onto an auxiliary body, and during the build-up the build-up burner and the growing soot body are rotated relative to one another, and the burner is at the same time held at an unvarying distance from the growing end of the hollow cylinder and centrally above the predetermined cross section of the upwardly growing end of the cylinder wall. The penetration of soot into the interior of the cylinder is prevented by means of a directed gas stream.

Abstract: A feeder system for the production of glass filaments is rendered dripless or non-dripless on demand by controlling the pressure of the air in contact with the streams and beads of the orificed discharge wall. Preferably, the feeder is rendered non-dripless when the restart of filament formation from idled orifices is desired.

Abstract: A feeder system for the production of glass filaments is provided with a shallow layer of molten glass over the discharge wall in combination with a flow control means adapted to regulate the depth of the layer to provide dripless and non-dripless operation as desired. Preferably, the feeder is rendered non-dripless when the restart of filament formation from the idled orifices is desired.

Abstract: A feeder for the production of glass filaments is provided with a shallow layer of glass over the discharge wall in combination with a fluid filled cavity capable of being pressure regulated to render the operation dripless or non-dripless as desired. Preferably, the feeder is rendered non-dripless when the restart of filament formation from idled orifices is desired.

Abstract: A method for the regeneration of a spent aqueous ammonium bifluoride-hydrogen peroxide solder stripping solution containing contaminant tin ions comprising adding potassium ions to the solution to precipitate a filterable tin-potassium compound.

Abstract: Optical fibres are drawn from a solid preform which consists substantially of SiO.sub.2 and doped SiO.sub.2. After leaving the heating zone, the fiber is guided through a space having a laminar gas flow to restrict the temperature drop across the fiber so that no extra stresses are incorporated in the fiber upon cooling. A device for performing this method comprises a quartz pipe through which the fiber is guided and in which a laminar gas flow is maintained.

Abstract: The invention relates to a method of strengthening a glass article formed of sheet glass produced by the float process. The strengthening method includes a known ion exchange treatment to replace alkali metal ions in the surface layers of the glass with, e.g., alkali metal ions larger in ionic radius such as potassium ions. To prevent warping of the glass article during the ion exchange treatment by the influence of a metal element such as tin used as the molten metal in the float process and diffused into one surface of the sheet glass, the glass article is pretreated by contacting at least said surface with an external source of sodium ions and/or lithium ions and heating the glass article together with the external source of the alkali metal ions at 350.degree.-650.degree. C. for 0.01-100 hr. The pretreatment is neither preceded nor followed by grinding or polishing of said surface of the glass.

Abstract: A valve apparatus for the precise regulation of a stream of molten material such as molten rock or slag as it issues from a primary melter or holding device, comprising a frame retaining a valve, the valve comprising a pair of plate-form valve members, one fixed and one movable with respect to the other, each having an aperture or orifice provided therein. Maximum rate of discharge occurs when the apertures are in juxtaposition, and flow cut-off occurs when the apertures are not in juxtaposition. Power operated means is provided for the movable valve member to obtain proper stream regulation or complete cut-off. Each valve member is formed of a plate of metal having an internal channel through which water is circulated to reduce the temperature of the valve member and to prevent its destruction by overheating.

Abstract: A downwardly moving cylindrical veil of mineral fibers is distributed to form a mineral fiber product by impinging on the interior of the veil jets of gas from an internal blower positioned within the veil to increase the angular velocity of the veil, thereby causing the veil tobreak up into an incoherent flow of mineral fibers.

Abstract: A method of consolidating fine pores of a porous glass by impregnating the fine pores with an energy decomposable compound exemplified by SiH.sub.4. Energy is applied to the decomposable compound thereby forming active species which bond with each other and the functional groups on the surface of the fine pores three-dimensionally to thus form a glass network structure in the pores.