US3745321A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of control over operating conditions of an apparatus for plasma-arc treatment of articles and an apparatus for plasma-arc treatment
Assignee: Individual
•
Filing: 1971-07-28
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Granted: 1973-07-10
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Expires: 1991-07-28
Abstract
Abstract An apparatus for treating an article or workpiece by plasma arc has a plasmatron, a cathode from which a plasma arc is struck to the workpiece through a conductive nozzle and a controlled current supply source having a control circuit and connected between the cathode and the workpiece. A voltage-sensitive element is also connected between the cathode and nozzle. The voltage-sensitive element is essentially a filter adapted to pass frequencies exceeding the ripple frequency of the plasma-arc supply source, and a threshold element. During a voltage jump between the cathode and the article the threshold element generates a pulse which is supplied to the control circuit of the plasma-arc supply source, thus causing discontinuation of the supply current increase and, consequently, obviating the plasmaarc current increase. This prevents undesirable erosion of the nozzle and causes a smooth operation of the apparatus.
Inventors
- 👤 M Tkachev
- 👤 L Linetsky
- 👤 I Shapiro
- 👤 L Persits
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 21:04
CPC Classifications
B; B23; B23K; B23K9/00; B23K9/06; B23K9/073; B23K9/0732; B23K10/00; B23K10/006
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
161 words
An apparatus for plasma-arc treatment of an article, comprising: a plasma-arc torch including a cathode and an electro-conductive nozzle through which a plasma-producing gas passes, a plasma arc passing inside said nozzle and burning between said cathode and said article; a current source having a control circuit and connected between the cathode and said article and adapted to supply electric current to said plasma arc; a voltage-sensitive element connected between said cathode and nozzle, which voltage-sensitive element is formed by an electric filter adaPted to pass frequencies exceeding a ripple frequency of said source and a threshold element connected to the filter output and connected by the output to the control circuit of said source, said threshold element being adapted to generate, upon the supply to its input of a signal corresponding to a voltage jump between the cathode and the nozzle, a pulse supplied to the input of said control circuit to cause a discontinuation of the arc current increase.
Claim 2
Independent Claim
161 words
An apparatus for plasma-arc treatment of an article, comprising: a plasma-arc torch including a cathode and an electro-conductive nozzle through which a plasma-producing gas passes, a plasma arc passing inside said nozzle and burning between said cathode and said article; a current source having a control circuit and connected between the cathode and said article and adapted to supply electric current to said plasma arc; a voltage-sensitive element connected between said cathode and nozzle, which voltage-sensitive element is formed by an electric filter adaPted to pass frequencies exceeding a ripple frequency of said source and a threshold element connected to the filter output and connected by the output to the control circuit of said source, said threshold element being adapted to generate, upon the supply to its input of a signal corresponding to a voltage jump between the cathode and the nozzle, a pulse supplied to the input of said control circuit to cause a discontinuation of the arc current increase.
Claim 3
Dependent Claim
45 words
An apparatus according to claim 1, wherein between the output of the voltage-sensitive element and the input of the control circuit of the source there is placed a pulse counter adapted to fully disconnect said supply source when a preset number of pulses is exceeded.
Claim 4
Independent Claim
217 words
An apparatus for plasma-arc cutting of an article, comprising: a plasma-arc torch including a cathode and an electro-conductive nozzle through which a plasma-producing gas passes, a plasma arc passing inside said nozzle and burning between said cathode and article; a current supply source having a control circuit and electrically connected between said cathode and article, the afore-said source being made up by controllable pulse and direct current generators connected in parallel with a cathode-article gap; a setter of current amplitude of said generators; a controller of current amplitude of said generators; a voltage-sensitive element connected between said cathode and nozzle, said voltage-sensitive element being formed by a filter adapted to pass frequencies exceeding a ripple frequency of said supply source and a threshold element connected to the filter output, connected by its output to the controller and adapted to generate, upon the occurrence at the filter output of a signal corresponding to a voltage jump between the cathode and the nozzle, a pulse for said controller to shape a signal causing a discontinuation of current increase from said current supply source; a commutator having two stable states, via which commutator said setter and controller are connected to the current source for their separate connection in each of the commutator states with said pulse and direct current generators.
Claim 5
Independent Claim
217 words
An apparatus for plasma-arc cutting of an article, comprising: a plasma-arc torch including a cathode and an electro-conductive nozzle through which a plasma-producing gas passes, a plasma arc passing inside said nozzle and burning between said cathode and article; a current supply source having a control circuit and electrically connected between said cathode and article, the afore-said source being made up by controllable pulse and direct current generators connected in parallel with a cathode-article gap; a setter of current amplitude of said generators; a controller of current amplitude of said generators; a voltage-sensitive element connected between said cathode and nozzle, said voltage-sensitive element being formed by a filter adapted to pass frequencies exceeding a ripple frequency of said supply source and a threshold element connected to the filter output, connected by its output to the controller and adapted to generate, upon the occurrence at the filter output of a signal corresponding to a voltage jump between the cathode and the nozzle, a pulse for said controller to shape a signal causing a discontinuation of current increase from said current supply source; a commutator having two stable states, via which commutator said setter and controller are connected to the current source for their separate connection in each of the commutator states with said pulse and direct current generators.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-07-09 | 1977-01-08 | 1977-07-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-07-09 | 1981-01-08 | 1981-07-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-07-09 | 1985-01-08 | 1985-07-10 | $7700.00 | Window Closed / Lapsed |