Patent ID: 6227009
Filing Date: 2001-05-08
Classification: C03B,C03C,D04H

Abstract:
A method of making fine diameter glass fibers, comprising:introducing molten glass into a rotary fiberization disc with an annular peripheral wall having a plurality of fiberizing orifices therein; the peripheral wall of the rotary fiberization disc having an exterior surface through which the fiberizing orifices pass; the fiberizing orifices having a diameter of about 0.023 inches or greater and having an effective open area for the passage of molten glass through the orifices between about 20 cm.sup.2 and about 80 cm.sup.2 ; and the molten glass having a viscosity between about 250 poise and about 2000 poise at a fiberizing temperature to be maintained within the rotary fiberization disc;maintaining the molten glass within the disc at the fiberizing temperature;rotating the rotary fiberization disc at a rate to cause the external surface of the peripheral wall of the rotary fiberization disc to have a velocity and to cause primary glass fibers to exit from the fiberizing orifices;the molten glass passing through the fiberizing orifices having a velocity between about 3 cm/minute and about 15 cm/minute;a ratio of the velocity of the external surface of the peripheral wall of the rotary fiberization disc to the velocity of the molten glass passing through the fiberizing orifices being between about 20,000 to 1 and about 40,000 to 1;directing a curtain of hot combustion gases from an attenuating burner onto the primary glass fibers exiting the fiberizing orifices; the ratio of the BTU content of the fuel expended forming the hot combustion gases per pound of molten glass being fiberized to the BTU content of a pound of molten glass being fiberized being between about 10 to 1 and about 30 to 1; andcreating an air curtain external of the fiberizing disc, by discharging air from an air ring, to inspirate air downward past the outer peripheral surface of the fiberizing disc and create with the hot combustion gases exiting the attenuating burner a curtain of hot, high velocity heated air and combustion gases to attenuate the primary fibers and form fine diameter fibers from the primary fibers; the air forming the air curtain having a velocity exiting the air ring; a ratio of the velocity of the air forming the air curtain to the velocity of the molten glass passing through the fiberizing orifices being between about 400,000 to 1 and about 1,200,000 to 1.