The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 03, 1984
Filed:
Jun. 23, 1982
International Telephone and Telegraph Corporation, New York, NY (US);
Abstract
In order to provide a high power heat source having a very clean and invariable heat flux, a ring plasma is induced in a heating zone of a plasma torch including a plurality of coaxial tubular elements and the optical fiber is drawn through a channel passing axially through the center of the plasma torch and of the ring-shaped plasma. In this manner the preform from which the fiber is drawn can be placed in close proximity to the induced plasma without exposure to non-symmetrical temperature variations. Cooling gas passes through the heating zone either in an annular stream surrounding the plasma or in an annular stream passing through the center of the plasma around the preform and the fiber being drawn, or both. The heating zone is protected from environmental disturbances by an extension of the outer tubular element of the plasma torch which surrounds the heating zone. The plasma is induced by an RF source in an undisturbed stream of a plasma-forming gaseous medium, such as argon or a mixture of argon with oxygen, which flows through the heating zone.