Patent US4608473A successfully refreshed from Google Patents.
US4608473A
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Modified zirconia induction furnace
Assignee: Furukawa Electric North America Inc
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Filing: 1985-04-29
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Granted: 1986-08-26
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Expires: 2005-04-29
Abstract
Abstract A high temperature induction furnace (10) for drawing lightguide fiber (52) from a silica preform (44) has an axially located tubular zirconium dioxide susceptor (34) therein. Prior to use, at least a portion of the inside surface of the susceptor (34) is coated with a vapor deposited silica "soot" (54). The silica soot (54) is then consolidated at an elevated temperature. Surprisingly, such a technique substantially eliminates migration of zirconium dioxide particles from the susceptor (34) to the preform (44) and/or the fiber (52) without deleteriously affecting the susceptor (34) and/or the operation of the furnace (10).
Inventors
- 👤 Un C. Paek
- 👤 Charles M. Schroeder, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 07:52
CPC Classifications
C; C03; C03B; C03B37/00; C03B37/01; C03B37/02; C03B37/025; C03B37/029; C03B2205/00; C03B2205/60; C03B2205/62; C03B2205/63; C03B2205/64; C03B2205/70
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
52 words
A furnace for heating a silica lightguide preform to an elevated temperature in order to draw a fiber therefrom, comprising: a housing; a tubular zirconium dioxide heating element located within said housing; and a thin coating of silica on at least a portion of the inside surface of the tubular heating element.
Claim 2
Dependent Claim
52 words
A furnace for heating a silica lightguide preform to an elevated temperature in order to draw a fiber therefrom, comprising: a housing; a tubular zirconium dioxide heating element located within said housing; and a thin coating of silica on at least a portion of the inside surface of the tubular heating element.
Claim 3
Dependent Claim
55 words
An induction heating furnace for heating a silica lightguide preform to an elevated temperature in order to draw a fiber therefrom, the furnace comprising: a tubular zirconium dioxide susceptor; a high frequency induction coil surrounding the susceptor; and a thin coating of silica on at least a portion of the inside surface of the susceptor.
Claim 4
Dependent Claim
55 words
An induction heating furnace for heating a silica lightguide preform to an elevated temperature in order to draw a fiber therefrom, the furnace comprising: a tubular zirconium dioxide susceptor; a high frequency induction coil surrounding the susceptor; and a thin coating of silica on at least a portion of the inside surface of the susceptor.
Claim 5
Dependent Claim
21 words
The furnace as set forth in claim 2, comprising: an insulating zirconium dioxide grain interposed between the coil and the susceptor.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-08-25 | 1990-02-24 | 1990-08-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-08-25 | 1994-02-24 | 1994-08-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-08-25 | 1998-02-24 | 1998-08-26 | $7700.00 | Window Closed / Lapsed |