US3671655A - Electrical transfer type plasma arc melting furnace - Google Patents
Electrical transfer type plasma arc melting furnace Download PDFInfo
- Publication number
- US3671655A US3671655A US100729A US3671655DA US3671655A US 3671655 A US3671655 A US 3671655A US 100729 A US100729 A US 100729A US 3671655D A US3671655D A US 3671655DA US 3671655 A US3671655 A US 3671655A
- Authority
- US
- United States
- Prior art keywords
- furnace
- plasma arc
- transfer type
- arc melting
- type plasma
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 230000008018 melting Effects 0.000 title claims abstract description 17
- 238000002844 melting Methods 0.000 title claims abstract description 17
- 239000002184 metal Substances 0.000 claims abstract description 25
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 15
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 12
- 239000000203 mixture Substances 0.000 claims 1
- 239000011819 refractory material Substances 0.000 claims 1
- CPLXHLVBOLITMK-UHFFFAOYSA-N Magnesium oxide Chemical compound [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 description 2
- 229910002804 graphite Inorganic materials 0.000 description 2
- 239000010439 graphite Substances 0.000 description 2
- 229910001209 Low-carbon steel Inorganic materials 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000003628 erosive effect Effects 0.000 description 1
- 239000000395 magnesium oxide Substances 0.000 description 1
- 238000013021 overheating Methods 0.000 description 1
- 238000010079 rubber tapping Methods 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B7/00—Heating by electric discharge
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B7/00—Heating by electric discharge
- H05B7/02—Details
- H05B7/06—Electrodes
Definitions
- the cathode In a conventional transfer type plasma arc furnace, the cathode is placed in the center of a plasma jet torch and molten metal functions as the anode.
- the plasma arc current flows between the plasma jet torch and molten metal; therefore, the molten metal must be contacted to a bottom electrode connected with an electrical source.
- the said bottom electrode (ordinally made of graphite) which is usually placed in the furnace hearth, is often broken by the erosion caused by chemical reaction between the electrode and molten metal, overheating of molten metal or electrical joule heat. As, the said damage often appears at the early stage just after the charge of scraps, a stable plasma are cannot be maintained and the plasma arc melting cannot be 2 actually continued.
- rectifier 9 and a transformer 10, all of which are suitably arranged.
- this furnace will not have such a direct contact between the molten metal and the carbon electrode as seen in any conventional transfer type plasma arc melting furnace. Therefore, no increase of carbon content in the molten metal results. Moreover, a relatively small power loss caused by possible electric resistance of the metal electrode is incurred.
- plasma arc current can be stabilized and also plasma arc melting can be smoothly carried out.
- Results shown in Table 1 indicate operational conditions between a furnace of the present invention and a conventional furnace.
- the data in the table highlights the advantages of the present invention.
- the metal electrode 3 keeps a solid form with its one part in contact to the kneaded refractory 8 and semi-molten fonn 'IABLE 1 Assured Carbon eon- Electrodc eon- Melting plasma are tent in the sumption time Typo ol' furnace used currents (A) molten metal (kg/charge) (lr./r.)
- a metal electrode 3 is fixed in the cone shaped refractory 2 which, for example, is made of baked or unbaked magnesia, and contacts directly with scraps or molten metal 1.
- Electrically conductive materials 8 comprising refractory and carbon powder properly kneaded together are inserted between the said metal electrode 3 and the graphite electrode 4.
- the above described defects can be avoided and suitable electric conductivity can also be maintained by preparing the combined electrode composed of the metal electrode 3, compounded refractory 8 and the carbon electrode 4. This furnace, as shown in the drawing,
- furnace body 5 has a furnace body 5, a furnace cover 6, a plasma jet torch 7, a
- the metal electrode 3 which is in semi-molten form will be a little lost after tapping, quicker melting operation can be obtained by only exchanging the used metal electrode with a new one.
- An electrical transfer type plasma arc melting furnace with an upper cathode and a lower anode characterized in that said anode is a combined electrode composed of a metallic portion which directly contacts the scrap or molten metal in said furnace, a carbon portion which is connected to the electric source and an intermediate portion which comprises a,
Landscapes
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Plasma & Fusion (AREA)
- Vertical, Hearth, Or Arc Furnaces (AREA)
- Discharge Heating (AREA)
- Furnace Details (AREA)
Abstract
An electrical transfer type plasma arc melting furnace with one or more combined electrodes composed of a metal electrode having direct contact with the scrap or molten metal, a electric carbon electrode directly connected with the source and baked or unbaked electrically conductive compounded refractory which is inserted between the metal bar and the said carbon electrode arranged either in the furnace hearth or in the furnace wall.
Description
{Z l :3 1. d l o (Db-20 72 XR 3,671,655
U mted States Patent [151 3,671,655 Adachi et a]. [4 1 June 20, 1972 [54] ELECTRICAL TRANSFER TYPE [56] References Cited L P ASMA ARC MELTING FURNACE UNITED STATES PATENTS t [72] 3,290,542 12/1966 Lafferty ..3l3/23l x Japan 3,524,006 8/1970 Ebeling et al.... ..l3/l X 3,547,622 12/1970 Hutchinson ..l3/9 X [73] Assignee: Daldo-Seiko Kabushlkl Kaisha, Aichi-ken,
Japan Primary Examiner-Roy N. Envall, Jr. 22] Filed: Dec. 1970 Attorney-Stevens, Davis, Miller & Mosher [2]] Appl; No.: 100,729 [57] ABSTRACT 0 An electrical transfer type plasma arc melting furnace with [30] Forei n A li ti P i D m one or more combined electrodes composed of a metal electrode having direct contact with the scrap or molten metal, 2 Dec. 25, 1969 Japan ..44/ 104607 electric carbon eIecuode directly connected i the source and baked or unbaked electrically conductive compounded [52] U.S.Cl ..l3/l, l3/9,2l9/l2l P, reftactory which is inserted between the meta] b and the 3113/ 231 said carbon electrode arranged either in the furnace hearth or [5 l Int. Cl. ..I'l05b 7/00 in the furnace wall [58] Field ofSearch ..rl3/l,9; 2l9/l2l P; 313/231 2 Clalnu, 1 Drawing Figure ELECTRICAL TRANSFER TYPE PLASMA ARC MELTING FURNACE This invention relates to a combined electrode in a plasma arc melting furnace operated by an electrical transfer type plasma torch.
In a conventional transfer type plasma arc furnace, the cathode is placed in the center of a plasma jet torch and molten metal functions as the anode.
The plasma arc current flows between the plasma jet torch and molten metal; therefore, the molten metal must be contacted to a bottom electrode connected with an electrical source.
The said bottom electrode (ordinally made of graphite) which is usually placed in the furnace hearth, is often broken by the erosion caused by chemical reaction between the electrode and molten metal, overheating of molten metal or electrical joule heat. As, the said damage often appears at the early stage just after the charge of scraps, a stable plasma are cannot be maintained and the plasma arc melting cannot be 2 actually continued.
As described before this furnace will not have such a direct contact between the molten metal and the carbon electrode as seen in any conventional transfer type plasma arc melting furnace. Therefore, no increase of carbon content in the molten metal results. Moreover, a relatively small power loss caused by possible electric resistance of the metal electrode is incurred.
At the earlier stage of melting, plasma arc current can be stabilized and also plasma arc melting can be smoothly carried out.
These advantages accomplish a considerable reduction in melting time and provides for suitable melting of ultra low carbon steel.
Results shown in Table 1 indicate operational conditions between a furnace of the present invention and a conventional furnace. The data in the table highlights the advantages of the present invention.
The metal electrode 3 keeps a solid form with its one part in contact to the kneaded refractory 8 and semi-molten fonn 'IABLE 1 Assured Carbon eon- Electrodc eon- Melting plasma are tent in the sumption time Typo ol' furnace used currents (A) molten metal (kg/charge) (lr./r.)
This invention 3, 000 0. 001 0. 001 1.5 Others wlrielt have it direct eontnet between the molten metal and the electrode (350-900 0.15-0.30 0. 75-1. 50 2. 4
This invention may be fully understood by referring the attached drawing, which shows a vertical section of a typical furnace according to the present invention.
A metal electrode 3 is fixed in the cone shaped refractory 2 which, for example, is made of baked or unbaked magnesia, and contacts directly with scraps or molten metal 1.
Electrically conductive materials 8 comprising refractory and carbon powder properly kneaded together are inserted between the said metal electrode 3 and the graphite electrode 4.
According to the present invention, the above described defects can be avoided and suitable electric conductivity can also be maintained by preparing the combined electrode composed of the metal electrode 3, compounded refractory 8 and the carbon electrode 4. This furnace, as shown in the drawing,
has a furnace body 5, a furnace cover 6, a plasma jet torch 7, a
with the other part in contact to the molten metal 1.
Though the metal electrode 3 which is in semi-molten form will be a little lost after tapping, quicker melting operation can be obtained by only exchanging the used metal electrode with a new one.
What we claim is as follows: 1. An electrical transfer type plasma arc melting furnace with an upper cathode and a lower anode characterized in that said anode is a combined electrode composed of a metallic portion which directly contacts the scrap or molten metal in said furnace, a carbon portion which is connected to the electric source and an intermediate portion which comprises a,
Claims (2)
1. An electrical transfer type plasma arc melting furnace with an upper cathode and a lower anode characterized in that said anode is a combined electrode composed of a metallic portion which directly contacts the scrap or molten metal in said furnace, a carbon portion which is connected to the electric source and an intermediate portion which comprises a blend of refractory material and carbon.
2. An electrical transfer type plasma arc melting furnace according to claim 1 wherein said carbon portion is arranged either in the furnace hearth or in the furnace wall.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP44104607A JPS5031524B1 (en) | 1969-12-25 | 1969-12-25 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US3671655A true US3671655A (en) | 1972-06-20 |
Family
ID=14385091
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US100729A Expired - Lifetime US3671655A (en) | 1969-12-25 | 1970-12-22 | Electrical transfer type plasma arc melting furnace |
Country Status (6)
| Country | Link |
|---|---|
| US (1) | US3671655A (en) |
| JP (1) | JPS5031524B1 (en) |
| BE (1) | BE760918A (en) |
| CH (1) | CH533688A (en) |
| GB (1) | GB1311320A (en) |
| SE (1) | SE390825C (en) |
Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3742132A (en) * | 1970-05-23 | 1973-06-26 | Nippon Electric Co | Drum servo system of a video tape recorder for an electronic editing |
| US4217479A (en) * | 1977-04-29 | 1980-08-12 | Swiss Aluminium Ltd. | High temperature reactor |
| US4317984A (en) * | 1978-07-07 | 1982-03-02 | Fridlyand Mikhail G | Method of plasma treatment of materials |
| EP0056225A1 (en) * | 1981-01-08 | 1982-07-21 | VOEST-ALPINE Aktiengesellschaft | Plasma melting furnace |
| EP0132711A2 (en) * | 1983-07-28 | 1985-02-13 | BBC Aktiengesellschaft Brown, Boveri & Cie. | Dimensioning of a bottom electrode for a direct current arc furnace to minimize power losses |
| EP0133926A1 (en) * | 1983-07-28 | 1985-03-13 | BBC Aktiengesellschaft Brown, Boveri & Cie. | Bottom electrode for a direct current arc furnace |
| US4540433A (en) * | 1982-10-04 | 1985-09-10 | Council For Mineral Technology | Treatment of ferromanganese |
| WO1988009388A1 (en) * | 1987-05-26 | 1988-12-01 | The University Of Toronto Innovations Foundation | Process for treating liquid metals |
| US4940486A (en) * | 1987-05-26 | 1990-07-10 | The University Of Toronto Innovations Foundation | Process for treating liquid metals |
| US4964973A (en) * | 1988-10-14 | 1990-10-23 | Brunswick Corporation | Method and apparatus for producing titanium |
| US5283383A (en) * | 1992-02-13 | 1994-02-01 | The United States Of America As Represented By The Department Of Health And Human Services | Antitumor compound, compositions and method of use |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SE452690B (en) * | 1983-07-07 | 1987-12-07 | Asea Ab | DC arc furnace |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3290542A (en) * | 1963-07-26 | 1966-12-06 | Gen Electric | Triggered vacuum discharge device |
| US3524006A (en) * | 1967-10-19 | 1970-08-11 | Qualitats Und Edelstahl Kom Ve | Method and apparatus for controlling arc discharge in plasma arc furnaces |
| US3547622A (en) * | 1968-06-12 | 1970-12-15 | Pennwalt Corp | D.c. powered plasma arc method and apparatus for refining molten metal |
-
1969
- 1969-12-25 JP JP44104607A patent/JPS5031524B1/ja active Pending
-
1970
- 1970-12-22 US US100729A patent/US3671655A/en not_active Expired - Lifetime
- 1970-12-22 GB GB6095370A patent/GB1311320A/en not_active Expired
- 1970-12-22 SE SE7017403A patent/SE390825C/en unknown
- 1970-12-24 CH CH1912470A patent/CH533688A/en not_active IP Right Cessation
- 1970-12-28 BE BE760918A patent/BE760918A/en not_active IP Right Cessation
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3290542A (en) * | 1963-07-26 | 1966-12-06 | Gen Electric | Triggered vacuum discharge device |
| US3524006A (en) * | 1967-10-19 | 1970-08-11 | Qualitats Und Edelstahl Kom Ve | Method and apparatus for controlling arc discharge in plasma arc furnaces |
| US3547622A (en) * | 1968-06-12 | 1970-12-15 | Pennwalt Corp | D.c. powered plasma arc method and apparatus for refining molten metal |
Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3742132A (en) * | 1970-05-23 | 1973-06-26 | Nippon Electric Co | Drum servo system of a video tape recorder for an electronic editing |
| US4217479A (en) * | 1977-04-29 | 1980-08-12 | Swiss Aluminium Ltd. | High temperature reactor |
| US4317984A (en) * | 1978-07-07 | 1982-03-02 | Fridlyand Mikhail G | Method of plasma treatment of materials |
| EP0056225A1 (en) * | 1981-01-08 | 1982-07-21 | VOEST-ALPINE Aktiengesellschaft | Plasma melting furnace |
| US4540433A (en) * | 1982-10-04 | 1985-09-10 | Council For Mineral Technology | Treatment of ferromanganese |
| EP0132711A2 (en) * | 1983-07-28 | 1985-02-13 | BBC Aktiengesellschaft Brown, Boveri & Cie. | Dimensioning of a bottom electrode for a direct current arc furnace to minimize power losses |
| EP0132711A3 (en) * | 1983-07-28 | 1985-03-13 | BBC Aktiengesellschaft Brown, Boveri & Cie. | Dimensioning of a bottom electrode for a direct current arc furnace to minimize power losses |
| EP0133926A1 (en) * | 1983-07-28 | 1985-03-13 | BBC Aktiengesellschaft Brown, Boveri & Cie. | Bottom electrode for a direct current arc furnace |
| WO1988009388A1 (en) * | 1987-05-26 | 1988-12-01 | The University Of Toronto Innovations Foundation | Process for treating liquid metals |
| US4940486A (en) * | 1987-05-26 | 1990-07-10 | The University Of Toronto Innovations Foundation | Process for treating liquid metals |
| US4964973A (en) * | 1988-10-14 | 1990-10-23 | Brunswick Corporation | Method and apparatus for producing titanium |
| US5283383A (en) * | 1992-02-13 | 1994-02-01 | The United States Of America As Represented By The Department Of Health And Human Services | Antitumor compound, compositions and method of use |
Also Published As
| Publication number | Publication date |
|---|---|
| BE760918A (en) | 1971-05-27 |
| JPS5031524B1 (en) | 1975-10-13 |
| CH533688A (en) | 1973-02-15 |
| SE390825C (en) | 1981-09-28 |
| SE390825B (en) | 1977-01-24 |
| GB1311320A (en) | 1973-03-28 |
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