Provided is a method for producing glass fiber, capable of stably performing the spinning of glass fibers without mixing of red crystals in glass fibers. When glass fibers are formed by discharging, from a nozzle tip, a molten glass obtained by melting glass raw materials mixed so as to give a glass composition including, when melted, in relation to the total amount thereof, SiO.sub.2 in a range from 57.0 to 62.0% by mass, Al.sub.2O.sub.3 in a range from 15.0 to 20.0% by mass, MgO in a range from 7.5 to 12.0% by mass, and CaO in a range from 9.0 to 16.5% by mass, and having a total content of SiO.sub.2, Al.sub.2O.sub.3, MgO and CaO of 98.0% by mass or more, the glass composition includes B.sub.2O.sub.3, Li.sub.2O, or B.sub.2O.sub.3 and Li.sub.2O as an additive or additives capable of suppressing the generation of red crystals.

Described herein is a method of forming a smelting byproduct that can be formed into an inorganic fiber, the method comprising: a) introducing silicomanganese slag and a smelting additive into a submerged arc furnace comprising a collection zone; b) smelting the silicomanganese slag into a silicomanganese metal and a smelting byproduct, whereby the silicomanganese metal settles to a lower portion of the collection zone and the smelting byproduct gathers in an upper portion of the collection zone due to density differential between the silicomanganese metal and the smelting byproduct; c) flowing the smelting byproduct from the collection zone from a first outlet; and d) flowing the silicomanganese metal from the collection zone from a second outlet.

Described herein is a method of forming a smelting byproduct that can be formed into an inorganic fiber, the method comprising: a) introducing silicomanganese slag and a smelting additive into a submerged arc furnace comprising a collection zone; b) smelting the silicomanganese slag into a silicomanganese metal and a smelting byproduct, whereby the silicomanganese metal settles to a lower portion of the collection zone and the smelting byproduct gathers in an upper portion of the collection zone due to density differential between the silicomanganese metal and the smelting byproduct; c) flowing the smelting byproduct from the collection zone from a first outlet; and d) flowing the silicomanganese metal from the collection zone from a second outlet.

A glass cane is manufactured by filling a glass tube with a combination of glass structures forming a cross-sectional pattern within the glass tube, to form a preform. The preform is attached to a draw assembly, such as a draw tower. The draw assembly is operated to draw the preform to a reduced-diameter glass cane by passing the preform through a furnace of the draw assembly while pulling the preform or the reduced-diameter glass cane and rotating the preform or the reduced-diameter glass cane.

A method of manufacturing an optical fiber, in which a coating is provided on a bare optical fiber, includes winding the optical fiber around a bobbin such that a strain relaxation coefficient T.sub./K is less than or equal to 292, and an one-layer strain .sub.n is greater than or equal to 0.01.

A nozzle tip for producing glass fibers has a pair of long-side walls and a pair of short-side walls, each of the long-side walls and the short-side walls containing platinum or a platinum alloy, and a nozzle orifice for discharging the glass melt, the nozzle orifice being formed by the long-side walls and the short-side walls. The nozzle orifice has a flat hole shape in horizontal cross-section. Each of the long-side walls has a cut-out on a discharge side of the glass melt, a width of the cut-out being 10-55% of a length of a longitudinal center axis of the flat hole shape of the nozzle orifice. The pair of long-side walls has a symmetrical shape about the center axis of the nozzle orifice. This nozzle tip makes it possible to efficiently produce glass fibers having a desired cross-sectional shape.

A nozzle tip for producing glass fibers has a pair of long-side walls and a pair of short-side walls, each of the long-side walls and the short-side walls containing platinum or a platinum alloy, and a nozzle orifice for discharging the glass melt, the nozzle orifice being formed by the long-side walls and the short-side walls. The nozzle orifice has a flat hole shape in horizontal cross-section. Each of the long-side walls has a cut-out on a discharge side of the glass melt, a width of the cut-out being 10-55% of a length of a longitudinal center axis of the flat hole shape of the nozzle orifice. The pair of long-side walls has a symmetrical shape about the center axis of the nozzle orifice. This nozzle tip makes it possible to efficiently produce glass fibers having a desired cross-sectional shape.

Processes and systems for producing glass fibers having regions devoid of glass using submerged combustion melters, including feeding a vitrifiable feed material into a feed inlet of a melting zone of a melter vessel, and heating the vitrifiable material with at least one burner directing combustion products of an oxidant and a first fuel into the melting zone under a level of the molten material in the zone. One or more of the burners is configured to impart heat and turbulence to the molten material, producing a turbulent molten material comprising a plurality of bubbles suspended in the molten material, the bubbles comprising at least some of the combustion products, and optionally other gas species introduced by the burners. The molten material and bubbles are drawn through a bushing fluidly connected to a forehearth to produce a glass fiber comprising a plurality of interior regions substantially devoid of glass.

Processes and systems for producing glass fibers having regions devoid of glass using submerged combustion melters, including feeding a vitrifiable feed material into a feed inlet of a melting zone of a melter vessel, and heating the vitrifiable material with at least one burner directing combustion products of an oxidant and a first fuel into the melting zone under a level of the molten material in the zone. One or more of the burners is configured to impart heat and turbulence to the molten material, producing a turbulent molten material comprising a plurality of bubbles suspended in the molten material, the bubbles comprising at least some of the combustion products, and optionally other gas species introduced by the burners. The molten material and bubbles are drawn through a bushing fluidly connected to a forehearth to produce a glass fiber comprising a plurality of interior regions substantially devoid of glass.

The invention relates to a micro-nozzle array comprising a plurality of capillaries comprising a first silica-based material and a second silica-based material substantially surrounding the first silica-based material of the plurality of capillaries, and a plurality of nozzles extending beyond a face of the micro-nozzle array, each nozzle corresponding to a single capillary, wherein each nozzle comprises the first silica-based material. The micro-nozzle array may be used in hydrodynamic or electro-osmotic applications. In one embodiment the micro-nozzle array is a multiple electrospray emitter. The invention also relates to methods for preparing and using micro-nozzle arrays.