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:
Feb. 27, 2001
Filed:
Feb. 05, 1999
Nobuaki Orita, Chiba, JP;
Tetsuya Kumada, Mie, JP;
Yoshiyuki Sakata, Mie, JP;
Hisashi Koaizawa, Chiba, JP;
The Furukawa Electric Co., Ltd., Tokyo, JP;
Abstract
An optical fiber drawing furnace capable of the prevention of entry of an ambient gas into an inner space thereof both effectively and economically, provided with a lower gas introduction portion through which inert gas is introduced into the inner space of the optical fiber drawing furnace, a chamber separated by a lower partition, and a bottom cover. The lower partition is arranged immediately below the lower gas introduction portion and has a first hole through which the chamber and the inner space are communicated. The bottom cover has a second hole through which the chamber and the atmosphere are communicated. An optical fiber is passed through the first and second holes. A controller detects a differential pressure between a pressure P,in the inner space and a pressure P,in the chamber and controls the suction flow by a pump for evacuating the gas in the chamber to maintain P,>P,The sizes of the first and second holes are defined as (L,/D,)<(L,/D,), where L,and L,are lengths of the holes and D,and D,are the diameters of the holes.