US3590242A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Making fused thorium carbide-tungsten cathodes for electron guns
Assignee: General Electric Co
•
Filing: 1969-06-12
•
Granted: 1971-06-29
•
Expires: 1989-06-12
Abstract
Abstract The surface energy of a liquid phase of thorium compounds or alloys is used in fabricating cathodes by immersing the lower end of an inclined refractory metal tube into a powder mixture of elemental thorium and tungsten carbide, heating to a temperature above the melting point of the mixture so that the liquid mixture flows up the inside of the tube by capillary attraction, cooling and cutting the tube into sections of length for cathode bodies. A convex hemispherical emissive surface for the thermionic cathode is formed by electron beam melting the end of the thin rod of a thorium compound or alloy.
Inventors
- 👤 Homer H Glascock Jr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 11:51
CPC Classifications
H; H01; H01J; H01J9/00; H01J9/02; H01J9/04; Y; Y10; Y10T; Y10T428/00; Y10T428/12; Y10T428/12493; Y10T428/1266; Y10T428/12771
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
27 words
The method of claim 1 which includes cutting the cooled tube with fused mixture therein into sections to form a plurality of cathode bodies of desired length.
Claim 2
Dependent Claim
15 words
The method of claim 1 wherein the mixture is melted in a refractory metal container.
Claim 3
Dependent Claim
14 words
The method of claim 1 wherein the refractory tube consists of tungsten and rhenium.
Claim 4
Dependent Claim
47 words
The method of claim 1 which includes the steps of suspending the refractory metal tube the above the powder mixture with a fusible support and heating the tube, mixture, and support above the melting point of the support so that the tube drops into the molten mixture.
Claim 5
Dependent Claim
28 words
The method of claim 5 which includes providing guides for the dropping tube so that it descends substantially vertically into the mixture and is supported in the mixture.
Claim 6
Dependent Claim
26 words
The method of claim 6 which includes placing a weight at the top of the suspended tube to assist it in descending when the support fuses.
Claim 7
Dependent Claim
32 words
The method of claim 1 which includes the step of subjecting the end of a cathode body to a beam of electrons to melt the end and form The smooth, hemispherical surface.
References Cited (Backward Citations)
US3160780A
Cited
US3258636A
Cited
US3338988A
Cited
US3307241A
Cited
US3269804A
Cited
US3434812A
Cited
GB1046639A
Cited
US3405044A
Cited
US3474281A
Cited
US3488549A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-06-28 | 1974-12-28 | 1975-06-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-06-28 | 1978-12-28 | 1979-06-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-06-28 | 1982-12-28 | 1983-06-29 | $7700.00 | Window Closed / Lapsed |