Patent US3980802A successfully refreshed from Google Patents.
US3980802A
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US
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Method of arc control in plasma arc furnace torches
Assignee: Individual
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Filing: 1974-08-20
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Granted: 1976-09-14
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Expires: 1994-08-20
Abstract
Abstract A plasma arc remelting furnace system with improved components including mechanisms for independently vertically feeding and oscillating the metal blank through the top of the furnace. Multiple plasma arc torches (plasmatrons) are installed in a sealed chamber and adjustable operators enable angular disposition of individual torches. The torches have improved torch nozzles with heat sink construction enabling operation at higher temperatures, better stablized plasma arcs and longer torch life. The system can utilize ingot molds of various cross section shapes, i.e., round, square, rectangular and polygonal and, depending upon mold shape, the number of torches can differ. Operating circuits are provided for use with a plurality of different numbers (up to eight) of torches, either with direct current or alternating current power sources, and possible variations of circuits will enable using a larger number of torches.
Inventors
- 👤 Boris Evgenievich Paton
- 👤 Victor Iosifovich Lakomsky
- 👤 Gary Alexandrovich Melnik
- 👤 Anatoli Ivanovich Chvertko
- 👤 Alfred Iosifovich Bukalo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 19:38
CPC Classifications
F; F27; F27D; F27D11/00; F27D11/08; C; C22; C22B; C22B9/00; C22B9/16; C22B9/22; C22B9/226; H; H05; H05B; H05B7/00; H05B7/02; H05B7/10; H05H; H05H1/00; H05H1/24; H05H1/26; H05H1/32; H05H1/34; H05H1/3478
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
199 words
A method of preventing operational destruction of a plasma arc torch for use in making ingots by plasma arc remelting wherein the plasma arc torch has a center electrode, a hollow water-cooled elongate torch body and a nozzle end structure which is fastened to the end of the torch body and has a hollow water-cooled nozzle body surrounding and spaced from the lower end of the electrode to form an annular nozzle channel, comprising: substantial elimination of ablation of nozzle structure and burnthrough of nozzle structure by providing a plurality of electrically conductive heat sink material means mounted in the interior of the nozzle body, around and radially spaced from the electrode, and disposing each heat sink material means so that it provides heat sink material extending axially along the outer wall of the nozzle channel and disposed closer to the electrode than any surface portion of the nozzle body in the vicinity of the nozzle channel, to thereby control and direct the current path of intermittent arcing which occurs from electrode to nozzle structure during remelting to area and zones of the nozzle structure whereat ablation of material is minimized and burnthrough of nozzle walls does not occur.
Claim 2
Independent Claim
199 words
A method of preventing operational destruction of a plasma arc torch for use in making ingots by plasma arc remelting wherein the plasma arc torch has a center electrode, a hollow water-cooled elongate torch body and a nozzle end structure which is fastened to the end of the torch body and has a hollow water-cooled nozzle body surrounding and spaced from the lower end of the electrode to form an annular nozzle channel, comprising: substantial elimination of ablation of nozzle structure and burnthrough of nozzle structure by providing a plurality of electrically conductive heat sink material means mounted in the interior of the nozzle body, around and radially spaced from the electrode, and disposing each heat sink material means so that it provides heat sink material extending axially along the outer wall of the nozzle channel and disposed closer to the electrode than any surface portion of the nozzle body in the vicinity of the nozzle channel, to thereby control and direct the current path of intermittent arcing which occurs from electrode to nozzle structure during remelting to area and zones of the nozzle structure whereat ablation of material is minimized and burnthrough of nozzle walls does not occur.
Claim 3
Dependent Claim
87 words
A method of preventing operational destruction of a plasma arc torch as defined in claim 1 comprising: the step of assuring that intermittent arcing at the exit of the nozzle channel does not engage the nozzle body by disposing the electrically conductive heat sink material means with portions radially adjacent the electrode lower end and axially disposed beyond the terminal end of the electrode so that intermittent arcing at the exit of the nozzle channel impinges directly on the heat sink material rather than the nozzle wall.
Claim 4
Dependent Claim
19 words
A method as defined in claim 1, wherein the gas flow in the nozzle area is maintained substantially laminar.
Claim 5
Dependent Claim
28 words
A method as defined in claim 3 wherein the intermittent arcing is substantially confined to a zone beyond the terminal end plane of the primary nozzle body material.
Claim 6
Dependent Claim
35 words
A method as defined in claim 4, wherein the intermittent arcing is directed to electrically conductive material having a good heat conductivity coefficient and a melting temperature substantially higher than the primary nozzle body material.
Claim 7
Dependent Claim
30 words
A method as defined in claim 2, wherein the heat sink material is tungsten and portions of the tungsten are extended beyond the terminal edge plane of the nozzle body.
Claim 8
Dependent Claim
25 words
A method as defined in claim 6, further comprising eliminating water cooling of the nozzle body in the zone immediately adjacent the heat sink material.
Claim 9
Dependent Claim
19 words
A method as defined in claim 6, wherein plasma gas flow in the nozzle area is maintained substantially laminar.
Claim 10
Dependent Claim
38 words
A method as defined in claim 8 wherein the electrode and heat sink material project from the nozzle and the intermittent arcing is substantially confined to a zone adjacent but outside of the end of the nozzle body.
References Cited (Backward Citations)
US2951143A
Cited
US3790742A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-09-14 | 1980-03-15 | 1980-09-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-09-14 | 1984-03-15 | 1984-09-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-09-14 | 1988-03-15 | 1988-09-14 | $7700.00 | Window Closed / Lapsed |