US4608473A
Expired / Lapsed
US
⏱️ 0.0 years remaining
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 02:12
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.
References Cited (Backward Citations)
US3328143A
Cited
US3401227A
Cited
FR2013820A1
Cited
US3729335A
Cited
US3916047A
Cited
US4107450A
Cited
US4029466A
Cited
US4052153A
Cited
US4159891A
Cited
US4055391A
Cited
JPS5258549A
Cited
US4242553A
Cited
US4356152A
Cited
US4450333A
Cited
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 |