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:
Jul. 16, 1991
Filed:
Dec. 29, 1989
Applicant:
Inventors:
Ichiro Tsuchiya, Yokohama, JP;
Shinji Ishikawa, Yokohama, JP;
Masahide Saitoh, Yokohama, JP;
Yoichi Ishiguro, Yokohama, JP;
Hiroo Kanamori, Yokohama, JP;
Assignee:
Sumitomo Electric Industries, Ltd., Osaka, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
C03B / ; C03B / ; F27B / ;
U.S. Cl.
CPC ...
432206 ; 65157 ; 6537713 ; 6537415 ; 432242 ; 432244 ; 432253 ;
Abstract
There is provided a heating furnace comprising a furnace body, a cylindrical zone heater in the furnace body, a muffle tube installed through the furnace body for thermally treating a porous preform made of high purity quartz glass by moving the preform vertically therethrough and a partition means in the portion of the muffle tube projecting above the furnace body to divide an interior space of the muffle tube into an upper space and a lower one.