US3740592A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Thermionic converter
Assignee: Fuelcell Energy Inc
•
Filing: 1970-11-12
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Granted: 1973-06-19
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Expires: 1990-11-12
Abstract
Abstract A thermionic converter is provided in which a protective silicon carbide shell is provided around the refractory metal emitter of the converter to shield it from the hot gases of a fossil fuel heat source and prevent oxidation of the emitter. The silicon carbide shell is spaced from the emitter so that stresses are not set up which would cause crackling or breaking of the shell. Heat transfer between the protective shell and the emitter is effected by means of a metal conductor which is liquid at the operating temperature of the converter. To obtain a long-life unit the silicon carbide shell is formed by uniformly depositing silicon carbide on the outer surface of a rotating, heated graphite mandrel.
Inventors
- 👤 R Engdahl
- 👤 J Bedell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 03:32
CPC Classifications
H; H01; H01J; H01J45/00
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
12 words
The combination of claim 1, wherein said thermal connecting means is tin.
Claim 2
Dependent Claim
43 words
The combination of claim 1, wherein the space between said protective member and said emitter is of increased thickness beyond the active area of said emitter so that thermal expansion of said thermal connecting means does not substantially change the liquid level thereof.
Claim 3
Dependent Claim
79 words
In a thermionic converter, the combination of, a heat source, a cylindrical emitter, a cylindrical protective member concentric with said emitter and positioned between said heat source and said emitter, a heat conducting material positioned between said emitter and said protective member, said material being a solid at room temperature and becoming a heat transferring liquid at the operating temperature of the converter, and means for preventing damage to said protective member due to thermal expansion of said material.
Claim 4
Dependent Claim
10 words
The combination of claim 4, wherein said material is tin.
Claim 5
Dependent Claim
54 words
The combination of claim 4, wherein said protective member is positioned around said emitter and has a closed end portion into which said material flows when liquid, and a layer of fibrous heat resistant material positioned in said closed end portion which accommodates expansion of said heat conducting material without cracking said protective member.
Claim 6
Dependent Claim
105 words
In a thermionic converter, the combination of, a heat source, a cylindrical emitter, a cylindrical protective member concentric with said emitter and positioned between said heat source and said emitter, a heat conducting material positioned between said emitter and said protective member for a portion of the length tHereof, said material being a solid at room temperature and a heat transferring liquid at the operating temperature of the converter, and a cover gas in the space between said emitter and said protective member not occupied by said heat conducting material, said gas inhibiting the transport of vapors of said heat conducting material through said space.
Claim 7
Dependent Claim
12 words
The combination of claim 7, wherein said heat conducting material is tin.
Claim 8
Dependent Claim
10 words
The combination of claim 7, wherein said gas is argon.
Claim 9
Dependent Claim
38 words
The combination of claim 7, wherein said emitter and said protective member are joined together in one region of said space and said cover gas minimizes the condensation of vapors of said heat conductive material on said joint.
Claim 10
Dependent Claim
112 words
In a thermionic converter, the combination of, a heat source, a cylindrical emitter, a cylindrical protective member concentric with said emitter and positioned between said heat source and said emitter, a heat conducting material positioned between said emitter and said protective member for a portion of the length thereof, said material being a solid at room temperature and a heat transferring liquid at the operating temperature of the converter, means connecting said emitter and said protective member together adjacent one end thereof, said heat conducting material tending to vaporize at the operating temperature of the converter, and means for preventing vapors of said heat conductive material from condensing on said connecting means.
Claim 11
Dependent Claim
21 words
The combination of claim 11, wherein said last named means is a gas which does not condense at normal room temperature.
Claim 12
Dependent Claim
72 words
In a thermionic converter, the combination, of a tubular protective member positioned vertically and having a closed bottom end, a cylindrical emitter positioned inside said protective member and spaced therefrom, a heat conducting material positioned in the space between said emitter and said protective member, means joining said protective member to said emitter at the upper end thereof, and means for protecting said joint from oxidation due to exposure to the atmosphere.
Claim 13
Dependent Claim
81 words
In a thermionic converter, the combination of, a tubular protective member of silicon carbide, a cylindrical emitter of tungsten positioned inside said protective member and spaced therefrom, a heat conducting material positioned in the space between said emitter and said protective member, a tungsten ring connected to the upper end of said protective member, and a glass seal covering the joint between said ring and said protective member, thereby to protect said joint from oxidation due to exposure to the atmosphere.
Claim 14
Dependent Claim
24 words
The combination of claim 14, wherein said glass is a lead glass which is essentially a liquid at the operating temperature of said converter.
Claim 15
Dependent Claim
93 words
In a thermionic converter, the combination of, a tubular protective member of silicon carbide, a cylindrical emitter of tungsten positioned inside said protective member and spaced therefrom, a heat conducting material positioned in the space between said emitter and said protective member, a nickel supporting sleeve, a tungsten ring connected between said sleeve and the upper end of said protective member to support the same, and a glass seal covering said tungsten ring to protect the joints thereof to said sleeve and said protective member from oxidation due to exposure to the atmosphere.
Claim 16
Dependent Claim
42 words
The combination of claim 16, wherein said glass seal is liquid at the operating temperature of the converter and is contained by an annular silicon carbide member secured to the upper end of said protective member in the vicinity of said joints.
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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) | 1976-06-18 | 1976-12-18 | 1977-06-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-06-18 | 1980-12-18 | 1981-06-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-06-18 | 1984-12-18 | 1985-06-19 | $7700.00 | Window Closed / Lapsed |