Abstract: A glass composition to be used for manufacturing inorganic fiber has a composition that entirely or partly eliminates the use of expensive boron oxide that is employed to lower the glass softening point and the viscosity. The glass composition contains 45 to 75 wt % of SiO2, 1 to 6 wt % of Al2O3, 0 to 4 wt % of MgO, 0 to 15 wt % of CaO, 0 to 6 wt % of B2O3, 0.1 to 10 wt % of BaO, 0.1 to 25 wt % of SrO, 5 to 17 wt % of Na2O, 0.5 to 10 wt % of K2O and 0 to 3.5 wt % of Fe2O3.

Abstract: A process and an apparatus for producing glass fibers by centrifugal force are provided. Molten glass is fed into a hollow cylinder of rotating member which rotates at high speed by means of a driving device and is heated. The molten glass is ejected to an outside of a peripheral wall by centrifugal force generated by high speed rotation of the rotating member through orifices, each of which has different diameter, and which are provided alternately in a circumferential direction of the peripheral wall. A primary steam of molten glass is ejected. The primary streams is introduced into flame flow ejecting from drawing burners located at outside of the peripheral wall to form secondary fibers. A compressed gas flow is ejected to a direction at an acute angle through an ejecting outlet of an ejecting nozzle to collide the compressed fluid with the secondary fibers to thereby produce glass fibers by continuously.

Abstract: A glass composition to be used for manufacturing inorganic fiber has a composition that entirely or partly eliminates the use of expensive boron oxide that is employed to lower the glass softening point and the viscosity. The glass composition contains 45 to 75 wt % of SiO2, 1 to 6 wt % of Al2O3, 0 to 4 wt % of MgO, 0 to 15 wt % of CaO, 0 to 6 wt % of B2O3, 0.1 to 10 wt % of BaO, 0.1 to 25 wt % of SrO, 5 to 17 wt % of Na2O, 0.5 to 10 wt % of K2O and 0 to 3.5 wt % of Fe2O3.

Abstract: A process for forming glass filaments by utilizing centrifugal force, in which compressed gas is injected from a position near an interior of a flame port frame of a fiberizing burner toward a throat portion of a discharge port of the burner at an acute angle relative to the direction of discharge of a flame stream from the discharge port, so that the compressed gas is mixed with combustion exhaust gas at an inlet portion of the throat portion, and the mixed gas is injected from the discharge port of the burner in a direction generally parallel to the direction of the generatrix of the outer peripheral surface of the peripheral wall, thereby forming primary filaments into fine secondary filaments.