Oxyhydrogen flame torch for optical fiber drawing

Abstract

An oxyhydrogen torch for use in drawing an optical fiber from a preform without axial rotation includes four coaxial tubular elements bounding respective passages. The fiber is coaxially drawn through the innermost passage, and hydrogen, oxygen and an inert gas are respectively individually admitted into the successively outer passages at their upstream ends in the circumferential directions of the respective passages. Oxygen and hydrogen become mixed with one another and combust after leaving the downstream ends of the respective passages to form an annular oxyhydrogen flame in a heating zone of the torch around the portion of the preform from which the fiber is being drawn. The inert gas, such as argon or nitrogen, flows past the flame in the heating zone to shield the flame from environmental disturbances. The outermost tubular element has an extension which surrounds the heating zone and confines the stream of the shielding inert gas to provide an improved shielding effect for the flame, while being cooled by the shielding gas.

Dependencies are inferred from the claim text.