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:
Mar. 17, 2015
Filed:
Dec. 11, 2012
Applicant:
Fujikura Ltd., Koto-ku, Tokyo, JP;
Inventor:
Sho Endo, Sakura, JP;
Assignee:
Fujikura Ltd., Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C03B 37/014 (2006.01); C03B 37/012 (2006.01); G01M 3/28 (2006.01);
U.S. Cl.
CPC ...
G01M 3/2846 (2013.01); C03B 37/0146 (2013.01);
Abstract
A muffle tube inspection method inspects a muffle tube used for dehydrating and sintering a silica glass-based optical fiber preform, the muffle tube includes a sintering furnace provided with a furnace body covering a heater disposed around a periphery of the muffle tube. The method detects a crack generated at the muffle tube by measuring a pressure inside the furnace body while varying a pressure inside the muffle tube.