Patent US4147954A successfully refreshed from Google Patents.
US4147954A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Thermionic electron emitter
Assignee: E M I-Varian Ltd
•
Filing: 1977-07-07
•
Granted: 1979-04-03
•
Expires: 1997-07-07
Abstract
Abstract A thermionic electron emitter comprises a tube of wall thickness less than 0.1 mm, a body of thermionic electron emissive material compressed and sintered in the tube, and a ring, coaxial with the tube, within the body to provide constraint against cracking of the body.
Inventors
- 👤 Richard A. Tuck
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 06:04
CPC Classifications
H; H01; H01J; H01J1/00; H01J1/02; H01J1/13; H01J1/20; H01J1/28
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
61 words
A thermionic electron emitter to emit electrons when heated, including a tubular support having at least a thin wall portion of thickness less than 0.1mm, a body of thermionic electron emissive material compressed in the tubular support within the said thin wall portion, and a reinforcing ring, coaxial with the tube, within the body providing constraint against cracking of the body.
Claim 2
Dependent Claim
61 words
A thermionic electron emitter to emit electrons when heated, including a tubular support having at least a thin wall portion of thickness less than 0.1mm, a body of thermionic electron emissive material compressed in the tubular support within the said thin wall portion, and a reinforcing ring, coaxial with the tube, within the body providing constraint against cracking of the body.
Claim 3
Dependent Claim
26 words
An emitter according to claim 1 in which the tubular support is of uniform wall thickness around the body and beyond the position of the body.
Claim 4
Dependent Claim
26 words
An emitter according to claim 1 in which the tubular support has a transverse dimension of at least 3 mm and not less than 25 mm.
Claim 5
Dependent Claim
30 words
An emitter according to claim 1 in which the tubular support and reinforcing element are each of a refractory material selected from the group consisting of molybdenum, tungsten, molybdenum/rhenium alloy.
Claim 6
Dependent Claim
28 words
An emitter according to claim 1 in which the electron emission material is a mixture of a refractory matrix material, an electron emissive material and a reducer material.
Claim 7
Dependent Claim
20 words
An emitter according to claim 5, wherein the electron emissive material comprises Ba 5 Sr [WO 6 ] 2 .
Claim 8
Dependent Claim
16 words
An emitter according to claim 1, wherein the ring is physically separate from the tubular support.
Claim 9
Dependent Claim
19 words
An emitter according to claim 7 in which the ring is a close sliding fit in the tubular support.
Claim 10
Dependent Claim
17 words
An emitter according to claim 1, wherein the wall thickness of the support is 0.025mm or less.
Claim 11
Dependent Claim
24 words
An emitter according to claim 1, wherein the surface of the body is free to emit electrons across the whole bore of the support.
Claim 12
Dependent Claim
34 words
An emitter according to claim 10 further comprising a heating element in the tubular support, the surface of the body facing the heating element being free across the whole bore of the tubular support.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-04-02 | 1982-10-02 | 1983-04-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-04-02 | 1986-10-02 | 1987-04-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-04-02 | 1990-10-02 | 1991-04-03 | $7700.00 | Window Closed / Lapsed |