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:
Dec. 30, 2003
Filed:
Aug. 24, 2000
Toshiki Taru, Yokohama, JP;
Katsuya Nagayama, Yokohama, JP;
Kazuya Kuwahara, Yokohama, JP;
Ichiro Tsuchiya, Yokohama, JP;
Sumitomo Electric Industries, Ltd., Osaka, JP;
Abstract
A furnace for drawing an optical fiber provided with a muffle tube ( ) and inner tubes ( ′) connected to the upper end of the core tube, wherein a preform ( ) supported by a dummy rod ( ) at the upper part thereof is disposed inside the muffle tube ( ) and inner tubes ( ′) so as to be movable downward together with dummy rod ( ), the preform ( ) is heated and melted by a heater ( ) from the outside of the muffle tube ( ) and an optical fiber ( ) is pulled out from the lower end of the preform ( ); the furnace is further provided with one or a plurality of sets of separating plates ( ) adapted to partition a space in the inner tubes ( ′) above the preform ( ) into a plurality of portions in the advance direction of the preform and disposed in the space, and with gas blowing inlets ( ) disposed in the parts of wall surfaces of the inner tubes ( ′) which are below the separating plates ( ) and adapted to blow an inert gas into the inner tubes ( ′) and the muffle tube ( ), thereby preventing variations in diameter of the optical fiber ( ).