Patent ID: 6044663
Filing Date: 2000-04-04
Classification: C03B,H05B

Abstract:
A fiber optic draw furnace (10) for drawing an optical fiber (F) from a preform (P), having a heating element (22) having a shape for enclosing and heating the preform (P), and having a graphite liner (12) having a corresponding shape to the shape of the heating element (22) for providing a barrier between the heating element (22) and the preform (P),wherein either the graphite liner (12) is a high density extruded graphite liner (12) that is impregnated with vitreous carbon completely through its entire graphite liner matrix, or the heating element (22) is a high density extruded graphite heating element (22) that is impregnated with vitreous carbon completely through its entire graphite heating element matrix, or both; andwherein the fiber optic draw furnace (10) further comprises:an outer furnace shell (20);a bottom insulation plate (24) having a titanium carbide coating and being arranged in the outer furnace shell (20);a rigid bottom insulation ring (14) made of rigidified high purity graphite felt having a reflective coating (14a) and being arranged between the bottom insulation plate (24) and the outer furnace shell (20);an inner cylinder plate (26) having a titanium carbide coating and being arranged around the heating element (22) and resting on the bottom insulation plate (24);a rigid insulation insert (16) made of rigidified high purity graphite felt having a reflective coating (16a) being arranged around the inner cylinder (26) and resting on the bottom insulation plate (24); anda rigid insulation canister (18) made of rigidified high purity graphite felt having a reflective coating (18a) and being arranged between the rigid insulation insert (16) and the outer furnace shell (20).