Furnace and process for optical fiber drawing
CA 2011153 C · Owner: Sumitomo Electric Industries, Ltd. · Inventors: Takagi, Masahiro; Yoshimura, Ichiro; Matsuda, Yasuo
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A drawing furnace for an optical fiber comprises a member in which a preform for the optical fiber is accommodated, a muffle tube connected to the accommodating member, around which a heater is disposed and in which a tip portion of the preform is heated and melted. Inert purging gas is supplied to the muffle tube or to both the accommodating member and the muffle tube. The invention is characterized in that at least a portion of at least one of the muffle tube and the accommodating member comprises at least two furnace walls defining a space between them. The outermost wall has an inlet through which the purging gas is supplied to the space, and the innermost wall has an outlet through …
Read the whole patent
Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Filed February 28, 1990 and granted September 2, 1997. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended February 28, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by February 28, 2012.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.