Patent US3896332A successfully refreshed from Google Patents.
US3896332A
Expired / Lapsed
US
⏱️ 0.0 years remaining
High power quick starting magnetron
Assignee: MO Valve Co Ltd
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Filing: 1974-05-29
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Granted: 1975-07-22
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Expires: 1994-05-29
Abstract
Abstract A quick start magnetron comprising: an anode; a main cathode positioned adjacent the anode and providing by secondary electron emission due to electron back bombardment at least a major part of the electron current required for operation of the magnetron; and an electron gun employing a thermionic cathode of low thermal inertia arranged to direct a stream of electrons into the space between the anode and the main cathode to initiate operation of the magnetron.
Inventors
- 👤 Vincent Albert Heathcote
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 06:02
CPC Classifications
H; H01; H01J; H01J23/00; H01J23/02; H01J23/04; H01J23/05
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
130 words
A magnetron comprising: a secondary electron emissive main cathode; an anode resonator which defines a cylindrical space in which said main cathode is disposed so as to provide an annular space between the anode and cathode; an electron gun employing a thermionic cathode of low thermal inertia disposed at a position outside said cylindrical space defined by the anode and arranged to direct a stream of electrons into said annular space between the anode and said main cathode to initiate operation of the magnetron, whereafter at least the major part of the electron current required for operation of the magnetron is provided by said main cathode due to electron back bombardment; said thermionic cathode being sufficiently remote from said cylindrical space to not be subjected to significant electron back bombardment.
Claim 2
Dependent Claim
130 words
A magnetron comprising: a secondary electron emissive main cathode; an anode resonator which defines a cylindrical space in which said main cathode is disposed so as to provide an annular space between the anode and cathode; an electron gun employing a thermionic cathode of low thermal inertia disposed at a position outside said cylindrical space defined by the anode and arranged to direct a stream of electrons into said annular space between the anode and said main cathode to initiate operation of the magnetron, whereafter at least the major part of the electron current required for operation of the magnetron is provided by said main cathode due to electron back bombardment; said thermionic cathode being sufficiently remote from said cylindrical space to not be subjected to significant electron back bombardment.
Claim 3
Dependent Claim
40 words
A magnetron according to claim 1 including a solid rod of material of good thermal conductivity, one end of the rod constituting the main cathode of the magnetron and the other end of the rod being provided with cooling means.
Claim 4
Dependent Claim
19 words
A magnetron according to claim 1 wherein the main cathode comprises a body of an impregnated porous refractory material.
Claim 5
Dependent Claim
24 words
A magnetron according to claim 1 wherein the electron gun is arranged to direct an annular stream of electrons coaxially into said annular space.
Claim 6
Dependent Claim
41 words
A magnetron according to claim 4 wherein said electron gun thermionic cathode comprises a thin-walled metal tube having a coating of electron emissive material on its outer surface, the tube being disposed coaxially with said cylindrical space and axially spaced therefrom.
Claim 7
Dependent Claim
26 words
A magnetron according to claim 5 wherein said metal tube is arranged to be electrically heated by the passage of an electric current directly through it.
Claim 8
Dependent Claim
31 words
A magnetron according to claim 5 including a control electrode in the form of a non-magnetic annular member coaxially surrounding the end of the electron gun cathode adjacent said cylindrical space.
Claim 9
Dependent Claim
38 words
A magnetron according to claim 1 including two pole pieces for directing a magnetic field through said cylindrical space in operation, the electron gun cathodE being disposed coaxially in a bore extending through one of the pole pieces.
Claim 10
Dependent Claim
51 words
A magnetron according to claim 8 including a solid rod of material of good thermal conductivity which extends coaxially through a bore in the other pole piece, one end of the rod constituting the main cathode of the magnetron and the other end of the rod being provided with cooling means.
References Cited (Backward Citations)
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US2822499A
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-07-21 | 1979-01-20 | 1979-07-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-07-21 | 1983-01-20 | 1983-07-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-07-21 | 1987-01-20 | 1987-07-22 | $7700.00 | Window Closed / Lapsed |