US3736359A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electric furnace
Assignee: British Steel Corp
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Filing: 1972-03-29
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Granted: 1973-05-29
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Expires: 1992-03-29
Abstract
Abstract Particulate metal in flowable form or liquid metal is continually dispensed on to the charge in the furnace vessel through a tubular non-consumable electrode constituting a reservoir for this metal. The metal discharges through a nozzle on the tip of the electrode and an arc is sustained in the metal flowing between this nozzle and the charge surfaces. In the case of particulate metal this would normally comprise only part of the total metal charge ultimately in the furnace, unless the application is in respect of vacuum arc re-melting or refining where it would constitute the whole charge. Where liquid metal is employed this only constitutes a small proportion of the total charge. In the latter embodiment starting presents no problem since a conductive path is provided but, with particulate metal, where a conductive path is not provided initially, starting is effected with the aid of an auxilliary electrode.
Inventors
- 👤 B Bowman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 22:20
CPC Classifications
F; F27; F27D; F27D11/00; F27D11/08; C; C21; C21B; C21B13/00; C21B13/12; F27D3/00; F27D3/18
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
57 words
A method of steelmaking by melting a charge in an electric furnace, comprising: continually dispensing a flowable metal on to the charge through a nozzle on the tip of a tubular, nonconsumable electrode, and striking and sustaining an arc in the metal flowing between the electrode nozzle and the surface of the charge thereby melting the charge.
Claim 2
Independent Claim
57 words
A method of steelmaking by melting a charge in an electric furnace, comprising: continually dispensing a flowable metal on to the charge through a nozzle on the tip of a tubular, nonconsumable electrode, and striking and sustaining an arc in the metal flowing between the electrode nozzle and the surface of the charge thereby melting the charge.
Claim 3
Dependent Claim
23 words
A method according to claim 1, in which said flowable metal is a particulate metal constituted by prereduced iron pellets or steel balls.
Claim 4
Dependent Claim
33 words
A method according to claim 2, in which starting is effected by a retractable auxiliary conductive electrode initially bridging the gap between the electrode tip and the charge so as to promote breakdown.
Claim 5
Dependent Claim
33 words
A method according to claim 2, in which starting is effected by projecting an ionisable seeded fluid on to the gap between the electrode tip and the charge so as to promote breakdown.
Claim 6
Dependent Claim
36 words
A method according to claim 1, in which the method is performed in a vacuum-arc re-melting or refining furnace and, the flowable metal is a particulate metal and constitutes the whole of the ultimate vessel charge.
Claim 7
Dependent Claim
20 words
A method according to claim 2, in which a reducing gas is passed through the particulate metal in the electrode.
Claim 8
Independent Claim
106 words
A method of steelmaking by melting a charge in an electric furnace, comprising: continually dispensing a flowable metal on to the charge through a nozzle on the tip of a tubular non-consumable electrode, striking and sustaining an arc in the metal flowing between the electrode nozzle and the surface of the charge, and correlating the electrical operating parameters, the physical parameters of the electrode, and the flow rate of the metal so as to achieve a blanced condition in which the arc runs from just below the nozzle tip to the charge surface, whereby to melt the charge and to reduce erosion of the nozzle tip.
Claim 9
Independent Claim
106 words
A method of steelmaking by melting a charge in an electric furnace, comprising: continually dispensing a flowable metal on to the charge through a nozzle on the tip of a tubular non-consumable electrode, striking and sustaining an arc in the metal flowing between the electrode nozzle and the surface of the charge, and correlating the electrical operating parameters, the physical parameters of the electrode, and the flow rate of the metal so as to achieve a blanced condition in which the arc runs from just below the nozzle tip to the charge surface, whereby to melt the charge and to reduce erosion of the nozzle tip.
Claim 10
Dependent Claim
56 words
A method according to claim 7, in which said flowable metal is a particulate metal dispensed on to the charge, and a reducing gas is passed through the particulate metal and starting is effected by projecting an ionisable seeded fluid on to the gap between the electrode tip and the charge so as to promote breakdown.
Claim 11
Dependent Claim
39 words
A method according to claim 8, in which said electrode constitutes a reservoir for said flowable metal, and said flowable metal in said electrode provides a current conducting path between said electrode and the metal flowing from said nozzle.
Claim 12
Dependent Claim
96 words
Electric furnace steelmaking apparatus comprising a tubular, current conducting, non-consumable electrode constituting a reservoir for flowable, current conducting metal, and a non-current conducting nozzle at the tip of the electrode defining an orifice through which the metal is continuously dispensed on to the charge in the furnace, the flowable metal in said electrode providing a current conducting path between the current conducting electrode and the metal flowing from said nozzle whereby an arc may be struck and sustained in the metal flowing between the electrode nozzle and the surface of the charge for melting said charge.
Claim 13
Dependent Claim
96 words
Electric furnace steelmaking apparatus comprising a tubular, current conducting, non-consumable electrode constituting a reservoir for flowable, current conducting metal, and a non-current conducting nozzle at the tip of the electrode defining an orifice through which the metal is continuously dispensed on to the charge in the furnace, the flowable metal in said electrode providing a current conducting path between the current conducting electrode and the metal flowing from said nozzle whereby an arc may be struck and sustained in the metal flowing between the electrode nozzle and the surface of the charge for melting said charge.
Claim 14
Dependent Claim
38 words
Steelmaking apparatus according to claim 10, wherein said flowable metal is a particulate metal and wherein the orifice in the nozzle tip is circular and has a diameter at least eight times the mean diameter of the particles.
Claim 15
Dependent Claim
44 words
Steelmaking apparatus according to claim 11, wherein an auxiliary conductive electrode is mounted within the tubular electrode, the auxiliary electrode being movable towards and away from the charge for initially bridging the gap between the electrode tip and the charge to strike an arc.
Claim 16
Dependent Claim
27 words
Steelmaking apparatus acCording to claim 10, wherein the electrode is made from an electrically conductive metal, and wherein the nozzle tip is made from a refractory material.
Claim 17
Dependent Claim
32 words
Apparatus according to claim 10, wherein the electrode is of composite construction embodying both electrically conductive and heat insulating refractory sleeves, and wherein the nozzle tip is made from a refractory material.
Claim 18
Dependent Claim
37 words
Apparatus according to claim 10, wherein the electrode comprises an inner heat insulating refractory sleeve, an electrically conductive sleeve surrounding said refractory sleeve, and means connecting said electrically conductive sleeve with the interior of said tubular electrode.
Claim 19
Dependent Claim
12 words
Apparatus according to claim 10, wherein said flowable metal is liquid metal.
Claim 20
Dependent Claim
14 words
A method according to claim 1, in which said flowable metal is liquid metal.
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) | 1976-05-28 | 1976-11-27 | 1977-05-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-05-28 | 1980-11-27 | 1981-05-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-05-28 | 1984-11-27 | 1985-05-29 | $7700.00 | Window Closed / Lapsed |