Patent US3699384A successfully refreshed from Google Patents.
US3699384A
Expired / Lapsed
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Offswitching of liquid metal arc switching device by internal current diversion to an auxiliary electrode
Assignee: Raytheon Co
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Filing: 1971-09-07
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Granted: 1972-10-17
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Expires: 1991-09-07
Abstract
Abstract An enclosed vessel containing one or more anodes, a main cathode, one or more auxiliary cathodes, and means for maintaining a low pressure in the tube comprises a liquid-metal arc switching device. The main cathode is fed with a metal which is liquid at convenient temperatures, so that limited quantities of the metal are present and available on the cathode for arcing. The interior of the vessel is maintained at a low background pressure so that, during nonconduction, vacuum space insulation is provided between the anodes and the cathodes. Arc initiation is accomplished by any convenient initiator, and the arc runs upon the small amount of liquid metal fed at an appropriate rate to the main cathode. For arc extinction, at least one auxiliary cathode is positioned within the envelope.
Inventors
- 👤 Wilfried O Eckhardt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 20:13
CPC Classifications
H; H01; H01J; H01J13/00; H01J13/02; H01J13/04; H01H; H01H9/00; H01H9/52; H01H2009/523; H01J2893/00; H01J2893/0072; H01J2893/0088; H01J2893/0089
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
164 words
An electric switching device comprising: an enclosing vessel, an anode, a liquid metal cathode, and a condenser within said vessel, feed means for feeding liquid metal to a surface on said cathode, means for maintaining a subatmospheric pressure within said vessel, cooling means for cooling said condenser so that arcing from the liquid metal on the cathode produces a substantially conical plasma jet, said anode being positioned to intercept at least a portion of said plasma jet, the improvement comprising: an auxiliary cathode positioned within said vessel adjacent the plasma jet; power supply means connected between said liquid metal cathode and said auxiliary cathode for impressing a negative potential on said auxiliary cathode with respect to said liquid metal cathode to extract ions from said plasma jet to cause secondary electron emission from said auxiliary cathode at least equal to the original liquid metal cathode-to-anode current to cause quenching of the arc from said liquid metal cathode to said anode to stop conduction therebetween.
Claim 2
Dependent Claim
164 words
An electric switching device comprising: an enclosing vessel, an anode, a liquid metal cathode, and a condenser within said vessel, feed means for feeding liquid metal to a surface on said cathode, means for maintaining a subatmospheric pressure within said vessel, cooling means for cooling said condenser so that arcing from the liquid metal on the cathode produces a substantially conical plasma jet, said anode being positioned to intercept at least a portion of said plasma jet, the improvement comprising: an auxiliary cathode positioned within said vessel adjacent the plasma jet; power supply means connected between said liquid metal cathode and said auxiliary cathode for impressing a negative potential on said auxiliary cathode with respect to said liquid metal cathode to extract ions from said plasma jet to cause secondary electron emission from said auxiliary cathode at least equal to the original liquid metal cathode-to-anode current to cause quenching of the arc from said liquid metal cathode to said anode to stop conduction therebetween.
Claim 3
Dependent Claim
27 words
The switching device of claim 1 wherein said auxiliary cathode comprises a plurality of flat panels positioned substantially parallel to the flow direction of the plasma jet.
Claim 4
Dependent Claim
20 words
The switching device of claim 2 wherein said flat panels have edges intercepting the edge of the plasma jet cone.
Claim 5
Dependent Claim
31 words
The switching device of claim 1 wherein said liquid metal cathode and said anode face each other and said condenser surrounds the space between said facing liquid metal cathode and anode.
Claim 6
Dependent Claim
20 words
The switching device of claim 4 wherein said auxiliary cathode is positioned between said liquid metal cathode and said anode.
Claim 7
Dependent Claim
27 words
The switching device of claim 5 wherein said auxiliary cathode comprises a plurality of flat panels positioned substantially parallel to the flow direction of the plasma jet.
Claim 8
Dependent Claim
20 words
The switching device of claim 6 wherein said flat panels have edges intercepting the edge of the plasma jet cone.
Claim 9
Dependent Claim
39 words
The switching device of claim 1 wherein said auxiliary cathode is connected to be maintained at a temperature above the condensation temperature of the liquid metal and below the electron emission temperature of the material of said auxiliary cathode.
Claim 10
Dependent Claim
39 words
The switching device of claim 7 wherein said auxiliary cathode is connected to be maintained at a temperature above the condensation temperature of the liquid metal and below the electron emission temperature of the material of said auxiliary cathode.
Claim 11
Independent Claim
244 words
The method of offswitching a liquid metal arc switching device having an enclosing vessel, with an anode, a liquid metal cathode, and a condenser within the vessel and arranged so that the pressure within the vessel is sufficiently low during arcing that a substantially conical plasma jet issues from an arc spot on the liquid metal cathode toward the anode, and which vessel contains a secondary cathode adjacent the plasma jet, comprising the steps of: causing a liquid metal arc between the liquid metal cathode and the anode by applying a potential therebetween and causing current to flow therebetween while maintaining the background pressure sufficiently low by cooling of the condenser to cause an arc between the cathode and the anode in the form of a substantially conical plasma jet; and offswitching saId switching device by applying sufficient potential to the auxiliary cathode with respect to the liquid metal cathode to extract sufficient ions from the plasma jet to impinge on the auxiliary cathode to cause secondary electron emission from the auxiliary cathode flowing to the anode at least equal to the original current flowing between the liquid metal cathode and the anode to extinguish the arc from the liquid metal cathode to cause cessation of the plasma jet and consequent cessation of current flow from the liquid metal cathode to the anode and to cause cessation of secondary emission electron flow from the auxiliary cathode to the anode to offswitch the switching device.
Claim 12
Independent Claim
244 words
The method of offswitching a liquid metal arc switching device having an enclosing vessel, with an anode, a liquid metal cathode, and a condenser within the vessel and arranged so that the pressure within the vessel is sufficiently low during arcing that a substantially conical plasma jet issues from an arc spot on the liquid metal cathode toward the anode, and which vessel contains a secondary cathode adjacent the plasma jet, comprising the steps of: causing a liquid metal arc between the liquid metal cathode and the anode by applying a potential therebetween and causing current to flow therebetween while maintaining the background pressure sufficiently low by cooling of the condenser to cause an arc between the cathode and the anode in the form of a substantially conical plasma jet; and offswitching saId switching device by applying sufficient potential to the auxiliary cathode with respect to the liquid metal cathode to extract sufficient ions from the plasma jet to impinge on the auxiliary cathode to cause secondary electron emission from the auxiliary cathode flowing to the anode at least equal to the original current flowing between the liquid metal cathode and the anode to extinguish the arc from the liquid metal cathode to cause cessation of the plasma jet and consequent cessation of current flow from the liquid metal cathode to the anode and to cause cessation of secondary emission electron flow from the auxiliary cathode to the anode to offswitch the switching device.
Claim 13
Dependent Claim
145 words
An electric switching device comprising: an enclosing vessel for maintaining a subatmospheric pressure within said vessel; an anode within said vessel; a main cathode within said enclosing vessel, said anode and said cathode being connectable for conduction of electricity therebetween in a metal arc mode wherein a plasma jet extends from an arc spot on said main cathode toward said anode during conduction, the improvement comprising: an auxiliary cathode positioned within said vessel adjacent the plasma jet; power supply means connected between said main cathode and said auxiliary cathode for impressing a negative potential on said auxiliary cathode with respect to said main cathode to extract ions from the plasma to cause secondary electron emission from said auxiliary cathode at least equal to the original main cathode-to-anode current to cause quenching of the arc from said main cathode to said anode to stop conduction therebetween.
Claim 14
Dependent Claim
145 words
An electric switching device comprising: an enclosing vessel for maintaining a subatmospheric pressure within said vessel; an anode within said vessel; a main cathode within said enclosing vessel, said anode and said cathode being connectable for conduction of electricity therebetween in a metal arc mode wherein a plasma jet extends from an arc spot on said main cathode toward said anode during conduction, the improvement comprising: an auxiliary cathode positioned within said vessel adjacent the plasma jet; power supply means connected between said main cathode and said auxiliary cathode for impressing a negative potential on said auxiliary cathode with respect to said main cathode to extract ions from the plasma to cause secondary electron emission from said auxiliary cathode at least equal to the original main cathode-to-anode current to cause quenching of the arc from said main cathode to said anode to stop conduction therebetween.
Claim 15
Dependent Claim
27 words
The switching device of claim 11 wherein said auxiliary cathode comprises a plurality of flat panels positioned substantially parallel to the flow direction of the plasma jet.
Claim 16
Dependent Claim
19 words
The switching device of claim 12 wherein said flat panels have edges intercepting the edge of the plasma jet.
Claim 17
Dependent Claim
30 words
The switching device of claim 13 wherein said auxiliary cathode is connected to be maintained at a temperature below the electron emission temperature of the material of said auxiliary cathode.
Claim 18
Dependent Claim
19 words
The switching device of claim 11 wherein said auxiliary cathode is positioned between said main cathode and said anode.
Claim 19
Dependent Claim
30 words
The switching device of claim 15 wherein said auxiliary cathode is connected to be maintained at a temperature below the electron emission temperature of the material of said auxiliary cathode.
References Cited (Backward Citations)
US2205230A
Cited
US3263121A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-10-17 | 1976-04-17 | 1976-10-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-10-17 | 1980-04-17 | 1980-10-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-10-17 | 1984-04-17 | 1984-10-17 | $7700.00 | Window Closed / Lapsed |