Patent EP0277550B1 successfully refreshed from Google Patents.
US4292276A
Expired / Lapsed
US
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Apparatus for producing silicon carbide
Assignee: Ibigawa Electric Industry Co Ltd
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Filing: 1979-03-09
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Granted: 1981-09-29
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Expires: 1999-03-09
Abstract
Abstract An apparatus for producing silicon carbide consisting mainly of β-type crystal are disclosed. The fine silicon carbide consisting mainly of β-type crystal is produced by charging the starting material of silica and carbon with a mole ratio of C/SiO 2 of 3.2-5.0 into a top portion of a vertical-type reaction vessel having a preheating zone, a heating zone and a cooling zone in this order, descending the starting material by gravity through the reaction vessel, heating the starting material in the heating zone at a temperature of 1,600°-2,100° C. by electrically indirect heating in horizontal direction to effect the formation of SiC, cooling the resulting reaction product in the cooling zone under a non-oxidizing atmosphere, and recovering the cooled product from the bottom portion of the reaction vessel to obtain a product having a composition ratio by weight of silicon carbide, silica and free carbon which lies within the area represented by the area ABCD shown in Fig. 1 of the accompanying drawings.
Inventors
- 👤 Ryo Enomoto
- 👤 Mitihiro Yoshioka
- 👤 Takao Yokoyama
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 18:50
CPC Classifications
C; C01; C01B; C01B32/00; C01B32/90; C01B32/914; C01B32/956; C01B32/963; C01B32/97; C01P; C01P2002/00; C01P2002/70; C01P2002/72; C01P2006/00; C01P2006/80
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
143 words
An apparatus for producing silicon carbide consisting mainly of β-type crystal, comprising a gravity-feed reaction vessel having an inlet for a starting material, a preheating zone, a heating zone, a cooling zone and a closeable outlet for a product in this order, and a heating means for the starting material in the heating zone by an electrically indirect heating; said heating zone being made of a graphite cylinder and having an effective heating width of 0.10-0.35 m; and further comprising a heat insulating layer for said heating zone, said layer composed of fine powder selected from the group consisting of carbon, graphite and mixtures thereof; wherein said heating means is composed of one or more graphite heating elements vertically arranged outside said graphite cylinder, and a graphite reflective cylinder arranged near the outside of said heating elements and inside said heat insulating layer.
Claim 2
Independent Claim
143 words
An apparatus for producing silicon carbide consisting mainly of β-type crystal, comprising a gravity-feed reaction vessel having an inlet for a starting material, a preheating zone, a heating zone, a cooling zone and a closeable outlet for a product in this order, and a heating means for the starting material in the heating zone by an electrically indirect heating; said heating zone being made of a graphite cylinder and having an effective heating width of 0.10-0.35 m; and further comprising a heat insulating layer for said heating zone, said layer composed of fine powder selected from the group consisting of carbon, graphite and mixtures thereof; wherein said heating means is composed of one or more graphite heating elements vertically arranged outside said graphite cylinder, and a graphite reflective cylinder arranged near the outside of said heating elements and inside said heat insulating layer.
Claim 3
Independent Claim
161 words
An apparatus for producing silicon carbide consisting mainly of β-type crystal, comprising a gravity-feed reaction vessel having an inlet for a starting material, a preheating zone, a heating zone, a cooling zone and a closeable outlet for a product in this order, and a heating means for the starting material in the heating zone by an electrically indirect heating; said heating zone having an effective heating width of 0.10-0.35 m; and further comprising a heat insulating layer for said heating zone, said layer composed of fine powders selected from the group consisting of carbon, graphite and mixtures thereof; wherein said heating zone is made of concentrically double inner and outer square or circular graphite cylinders in such a manner that a distance between the outer wall of the inner cylinder and the inner wall of the outer cylinder is within a range of 0.10-0.35 m and said heating means is arranged inside the inner cylinder and outside the outer cylinder, respectively.
Claim 4
Independent Claim
161 words
An apparatus for producing silicon carbide consisting mainly of β-type crystal, comprising a gravity-feed reaction vessel having an inlet for a starting material, a preheating zone, a heating zone, a cooling zone and a closeable outlet for a product in this order, and a heating means for the starting material in the heating zone by an electrically indirect heating; said heating zone having an effective heating width of 0.10-0.35 m; and further comprising a heat insulating layer for said heating zone, said layer composed of fine powders selected from the group consisting of carbon, graphite and mixtures thereof; wherein said heating zone is made of concentrically double inner and outer square or circular graphite cylinders in such a manner that a distance between the outer wall of the inner cylinder and the inner wall of the outer cylinder is within a range of 0.10-0.35 m and said heating means is arranged inside the inner cylinder and outside the outer cylinder, respectively.
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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) | 1984-09-28 | 1985-03-30 | 1985-09-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-09-28 | 1989-03-30 | 1989-09-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-09-28 | 1993-03-30 | 1993-09-29 | $7700.00 | Window Closed / Lapsed |