Patent US3597649A successfully refreshed from Google Patents.
US3597649A
Expired / Lapsed
US
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Device for plasma-arc treatment of materials
Assignee: Individual
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Filing: 1969-02-11
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Granted: 1971-08-03
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Expires: 1989-02-11
Abstract
Abstract A device for plasma-arc treatment of materials in active media wherein the cathode is made of hafnium which extends the service life of the cathode.
Inventors
- 👤 David Grigorievich Bykhovsky
- 👤 Alexandr Yakovlevich Medvedev
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 15:29
CPC Classifications
H; H05; H05H; H05H1/00; H05H1/24; H05H1/26; H05H1/32; H05H1/34; B; B23; B23K; B23K10/00; B23K35/00; B23K35/22; B23K35/222; H05H1/3436; H05H1/3442
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
122 words
In a plasma-arc device for treating material in an active medium having a central cathode holder and cathode, an annular passageway between the cathode holder and a housing, plasmagenerating gas inlet means to the annular passageway, at least one central nozzle between the cathode and a workpiece, and a power source, the improvement consisting in that said cathode is made of hafnium, the arc discharge between said cathode and the workpiece is stabilized by the plasma-generating gas passing concentric the cathode axis through the central nozzle and said cathode reacts with the active components in the plasmagenerating gas to form a high-melting film on itS working surface, which film has a low work function and substantially increases the life of said cathode.
Claim 2
Dependent Claim
122 words
In a plasma-arc device for treating material in an active medium having a central cathode holder and cathode, an annular passageway between the cathode holder and a housing, plasmagenerating gas inlet means to the annular passageway, at least one central nozzle between the cathode and a workpiece, and a power source, the improvement consisting in that said cathode is made of hafnium, the arc discharge between said cathode and the workpiece is stabilized by the plasma-generating gas passing concentric the cathode axis through the central nozzle and said cathode reacts with the active components in the plasmagenerating gas to form a high-melting film on itS working surface, which film has a low work function and substantially increases the life of said cathode.
Claim 3
Dependent Claim
29 words
A plasma-arc device as claimed in claim 1 wherein said central nozzle is electrically insulated from said cathode and said cathode holder and central nozzle have coolant passages therein.
Claim 4
Dependent Claim
48 words
A plasma-arc device as claimed in claim 1 wherein said reactive components in the plasma-generating gas are selected from a group consisting of oxygen, nitrogen or carbon and said high-melting film is formed of a compound selected from the group consisting of oxides, nitrides or carbides of hafnium.
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) | 1974-08-02 | 1975-02-01 | 1975-08-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-08-02 | 1979-02-01 | 1979-08-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-08-02 | 1983-02-01 | 1983-08-03 | $7700.00 | Window Closed / Lapsed |