Electric furnace with insulated electrodes and process for producing molten metals
AssigneeAlabama Power Company
InventorCharles F. Hendrix
Life of this patent
Estimating the term…
Abstract
An electric arc furnace having a partially insulated electrode produces molten metal such as foundry iron from an iron source where little or no slag is produced. The furnace includes at least one insulated electrode assembly for immersing deep into the metal charge. The electrode assembly has an electrically conducting member coupled to an electrode. The electrode has a coupling member at the upper end for coupling with the electrically conducting member and a coupling member at the lower end for coupling with an adjacent electrode to form an electrode column. The coupling members can be an internally threaded recess in the ends thereof. An externally threaded coupling member can be threaded into the recesses of the electrodes for coupling two or more electrodes together.
Claims47
An electrode for an electric furnace comprising:
- an electrically conductive core having a first end, a second end and a longitudinal midsection between said ends, said first end of said conductive core having a first coupling member for connecting to a power source, and said second end having a second coupling member for coupling with a first end of an adjacent electrode;
- and
- an electrically insulating material surrounding and attached to said midsection, said second end of said core being free of said insulating material, said electrically insulating material forming a substantially continuous insulating layer over said midsection and being consumable during arcing in an electric arc furnace.
An electrode assembly for an electric furnace comprising:
- an electrically conducting member for connecting to an electrical power source, said electrically conducting member having first and second ends;
- and
- at least one electrode having an electrically conductive core with a first end, a second end and a longitudinal midsection between said ends, and having an electrically insulating material surrounding and bonded to said midsection forming a substantially continuous electrically insulating layer, said first end of said core being coupled to said second end of said electrically conducting member, said electrically insulating layer being consumable during arcing in an electric arc furnace.
An electric furnace, comprising:
- a vessel having a melting zone and an inlet for feeding a charge into said vessel;
- at least one electrode assembly positioned in said vessel, said electrode assembly including an electrically conducting member having first and second ends, and including at least one electrode having an electrode core with a first end coupled to said electrically conducting member and having an electrically insulating material surrounding and bonded to a portion of said electrode core forming a substantially continuous insulating layer, said electrode assembly having a lower end substantially free of said insulating material and positioned in said melting zone, said first end of said electrically conducting member being coupled to an electrical power source, said insulating layer being consumable during arcing in said vessel to supply an alloying material to a molten metal produced in said vessel;
- and
- at least one second electrode positioned in said vessel for producing heat in said melting zone with said electrode assembly.
A process of producing molten metal in an electric furnace, comprising the steps of:
- continuously feeding an electrically conductive charge into an electric furnace to form a charge bed, said furnace having at least one electrode assembly and an additional electrode, said electrode assembly being coupled to a movable mounting structure for raising and lowering said electrode assembly with respect to a charge bed in said furnace, said electrode assembly having a first electrode core with first and second ends, a first electrically insulating material surrounding and bonded to said first electrode core, at least one second electrode core with a first end coupled to said second end of said first electrode core and having a second end, and a second electrically insulating material surrounding and bonded to said second electrode core forming a substantially continuous insulating layer with said first insulating material on said first electrode core to insulate said electrode assembly from said charge bed, said charge comprising at least one metal, metal compound or mixture thereof;
- immersing at least said electrode assembly into said charge bed at a depth independent of the electrical conductivity of said charge bed;
- supplying electrical energy to said electrode assembly and additional electrode to convey electric energy therebetween;
- and
- heating the charge bed in the furnace by the electrical energy between said electrodes to produce said molten metal, said insulating layer being consumed during heating to supply an alloying material to said molten metal.
Dependencies are inferred from the claim text.