US4228314A
Expired / Lapsed
US
⏱️ 0.0 years remaining
DC Arc furnace hearth
Assignee: ABB Norden Holding AB
•
Filing: 1979-02-27
•
Granted: 1980-10-14
•
Expires: 1999-02-27
Abstract
Abstract A DC arc furnace hearth is formed by a layer of carbon bricks above which an electrically relatively non-conductive refractory compound is rammed to contain a melt, and metal bars or rods inserted through the compound so that their upper ends are exposed to the melt and their bottom ends are in electrical connection with the bricks, forming an electrically conductive hearth. An arcing electrode above the melt can be connected to one pole of DC power and the hearth connected to the other so that an arc is formed between the electrode and melt.
Inventors
- 👤 Sven-Einar Stenkvist
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 18:50
CPC Classifications
F; F27; F27D; F27D11/00; F27D11/08; F27D11/10; C; C21; C21C; C21C5/00; C21C5/52; C21C5/5229; H; H05; H05B; H05B7/00; H05B7/02; H05B7/06; Y; Y02; Y02P; Y02P10/00; Y02P10/20
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
154 words
A DC arc furnace comprising an electrically conductive hearth adapted to contain a melt, at least one arcing electrode having a tip positioned substantially centrally above the hearth and adapted to form an arc with the melt, and means for connecting said electrode and hearth with DC power; wherein the improvement comprises said hearth comprising a substantially electrically non-conductive refractory compound rammed on a layer of electrically conductive bricks, and a cluster of vertically elongated metal elements which each extend through said compound from the top of the compound downwardly to electrical connection with said layer, said cluster extending from below said tip in all radial directions throughout an area large enough to carry DC power to a melt in the hearth and which is adequate to power said arc, and said bricks resting on a metal plate that is at least coextensive with said area and having means for connecting with said power.
Claim 2
Dependent Claim
154 words
A DC arc furnace comprising an electrically conductive hearth adapted to contain a melt, at least one arcing electrode having a tip positioned substantially centrally above the hearth and adapted to form an arc with the melt, and means for connecting said electrode and hearth with DC power; wherein the improvement comprises said hearth comprising a substantially electrically non-conductive refractory compound rammed on a layer of electrically conductive bricks, and a cluster of vertically elongated metal elements which each extend through said compound from the top of the compound downwardly to electrical connection with said layer, said cluster extending from below said tip in all radial directions throughout an area large enough to carry DC power to a melt in the hearth and which is adequate to power said arc, and said bricks resting on a metal plate that is at least coextensive with said area and having means for connecting with said power.
Claim 3
Dependent Claim
20 words
The furnace of claim 1 in which said area is symmetrical with respect to said tip of the arcing electrode.
Claim 4
Dependent Claim
50 words
The furnace of claim 1 in which a layer of electrically conductive material is interposed between said compound and said bricks and said elements are in the form of metal rods driven through said compound and into said material, the material being soft enough to be penetrated by the rods.
Claim 5
Dependent Claim
12 words
The furnace of claim 1 in which said bricks contain carbonaceous material.
Claim 6
Dependent Claim
19 words
The furnace of claim 1 in which said metal plate has means for cooling at least its central portion.
Claim 7
Dependent Claim
16 words
The furnace of claim 1 in which the bricks are magnesite-graphite bricks containing about 20% graphite.
References Cited (Backward Citations)
US941419A
Cited
US3835230A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-10-14 | 1984-04-14 | 1984-10-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-10-14 | 1988-04-14 | 1988-10-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-10-14 | 1992-04-14 | 1992-10-14 | $7700.00 | Window Closed / Lapsed |