US3950602A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Furnace installation operated by direct electrical heating according to the resistance principle in particular for preparation of silicon carbide
Assignee: Elektroschmelzwerk Kempten GmbH
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Filing: 1974-12-10
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Granted: 1976-04-13
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Expires: 1994-12-10
Abstract
Abstract In a furnace installation for producing silicon carbide in an intermittent operation, carbon electrodes arranged in the bottom of the furnace. A horizontally arranged resistance core is electrically connected to the carbon electrodes by vertically extending elements of an electrically conductive material having a higher specific conductivity than the core material. The resistivity of the connection between the electrodes and the core and the current passing through the connection produces a temperature lower than that necessary to form silicon carbide, and thereby prevents the destruction of the connections and electrodes normally caused by the downward movement of the silicon carbide roller.
Inventors
- 👤 Andreas Korsten
- 👤 Theodor Benecke
- 👤 Eugen Korndorfer
- 👤 Fritz Petersen
- 👤 Gunter Wiebke
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 19:10
CPC Classifications
H; H05; H05B; H05B3/00; H05B3/60; H05B3/02; H05B3/03
Claims Analysis
Total Claims: 29
Claim 1
Independent Claim
113 words
Furnace installation of the type operated by direct electric heating according to the resistance principle, for the preparation of silicon carbide from silica and carbonaceous material in intermittent operation, the current being supplied by means of electrodes through a resistance core of carbon horizontally inserted in a load consisting of a mixture of granulated coke, quartz sand and added materials, the improvement wherein the electrodes are arranged below the load as bottom electrodes and wherein a substantially vertical electric conducting means is arranged on top of each electrode connecting the electrodes to the resistance core, said connection being constructed separately of the resistance core and having a higher electric conductivity than the latter.
Claim 2
Dependent Claim
113 words
Furnace installation of the type operated by direct electric heating according to the resistance principle, for the preparation of silicon carbide from silica and carbonaceous material in intermittent operation, the current being supplied by means of electrodes through a resistance core of carbon horizontally inserted in a load consisting of a mixture of granulated coke, quartz sand and added materials, the improvement wherein the electrodes are arranged below the load as bottom electrodes and wherein a substantially vertical electric conducting means is arranged on top of each electrode connecting the electrodes to the resistance core, said connection being constructed separately of the resistance core and having a higher electric conductivity than the latter.
Claim 3
Dependent Claim
21 words
Furnace installation according to claim 1, wherein the upper contact surfaces of the bottom electrodes are level with the furnace floor.
Claim 4
Dependent Claim
22 words
Furnace installation according to claim 1, wherein the conducting means is of a material having a higher specific conductivity than the core.
Claim 5
Dependent Claim
17 words
Furnace installation according to claim 1, wherein the conducting means has a greater cross-section than the core.
Claim 6
Dependent Claim
26 words
Furnace installation according to claim 1, wherein the upper contact surfaces of the bottom electrodes are up to 10 cm below the bottom of the furnace.
Claim 7
Dependent Claim
22 words
Furnace installation according to claim 1, wherein the conducting means comprises a ballast of coke and graphite vertically mounted on the electrodes.
Claim 8
Dependent Claim
14 words
Furnace installation according to claim 6, wherein the ballast comprises tamped coke and graphite.
Claim 9
Dependent Claim
20 words
Furnace installation according to claim 1, wherein the conducting means comprises a ballast of graphite vertically mounted on the electrodes.
Claim 10
Dependent Claim
12 words
Furnace installation according to claim 8, wherein the ballast comprises tamped graphite.
Claim 11
Dependent Claim
25 words
Furnace installation according to claim 1, wherein the conducting means comprises a ballast of anthracite coal, graphite, and a binder vertically mounted on the electrodes.
Claim 12
Dependent Claim
10 words
Furnace installation according to claim 10 wherein ballast is tamped.
Claim 13
Dependent Claim
18 words
Furnace installation according to claim 1, wherein the conducting means comprises a compact material mounted on the electrodes.
Claim 14
Dependent Claim
35 words
Furnace installation according to claim 1, wherein the load is distributed over the bottom electrodes and the resistance core according to its natural cone and the installation is operated as a resistance furnace without walls.
Claim 15
Dependent Claim
13 words
Furnace installation according to claim 1, wherein the installation is equipped with walls.
Claim 16
Dependent Claim
23 words
Furnace installation according to claim 1, wherein graphite electrodes equipped with electrical current and cold water connections are used as said bottom electrodes.
Claim 17
Dependent Claim
23 words
Furnace installation according to claim 1, wherein carbon electrodes equipped with electrical current and cold water connections are used as said bottom electrodes.
Claim 18
Dependent Claim
25 words
Furnace installation according to claim 1, wherein tamped mass electrodes of graphite equipped with current and cold water connections are used as said bottom electrodes.
Claim 19
Dependent Claim
29 words
Furnace installation according to claim 1, wherein tamped mass electrodes of coke graphite and a binder equipped with current and cold water connections are used as said bottom electrodes.
Claim 20
Dependent Claim
24 words
Furnace installation according to claim 18 wherein said tamped mass is formed by carbonizing in an annealing furnace by heating to about 600° C.
Claim 21
Dependent Claim
16 words
Furnace installation according to claim 17, wherein metal conductors are embedded in the tamped mass electrodes.
Claim 22
Dependent Claim
17 words
Furnace installation according to claim 17, wherein metal cooling coils are embedded in the tamped mass electrodes.
Claim 23
Dependent Claim
26 words
Furnace installation according to claim 17, wherein current supply and cooling system in the form of cooled metal pipes are combined in the tamped mass electrodes.
Claim 24
Dependent Claim
17 words
Furnace installation according to claim 22, wherein the cooled metal pipes are made of streamlined copper tubes.
Claim 25
Dependent Claim
22 words
Furnace installation according to claim 1, wherein metal electrodes equipped with current and cold water connections are used as said bottom electrodes.
Claim 26
Dependent Claim
13 words
Furnace installation according to claim 24, wherein the electrodes are made of copper.
Claim 27
Dependent Claim
15 words
Furnace installation according to claim 18, wherein metal cooling coils are embedded in the electrodes.
Claim 28
Dependent Claim
81 words
A resistance heating furnace, comprising a furnace bottom, a pair of bottom electrodes, in said furnace bottom extending no higher than said furnace bottom, an electrically conductive connecting means extending substantially vertically from each of said electrodes, and a resistance core extending between said conductive connecting means above said furnace bottom, said connecting means having a higher conductivity than said core, and having inclined faces directed toward each other, said resistance core being positioned with its ends abutting said inclined faces.
Claim 29
Dependent Claim
81 words
A resistance heating furnace, comprising a furnace bottom, a pair of bottom electrodes, in said furnace bottom extending no higher than said furnace bottom, an electrically conductive connecting means extending substantially vertically from each of said electrodes, and a resistance core extending between said conductive connecting means above said furnace bottom, said connecting means having a higher conductivity than said core, and having inclined faces directed toward each other, said resistance core being positioned with its ends abutting said inclined faces.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-04-13 | 1979-10-13 | 1980-04-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-04-13 | 1983-10-13 | 1984-04-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-04-13 | 1987-10-13 | 1988-04-13 | $7700.00 | Window Closed / Lapsed |