US1954189A - Electric discharge tube - Google Patents
Electric discharge tube Download PDFInfo
- Publication number
- US1954189A US1954189A US407561A US40756129A US1954189A US 1954189 A US1954189 A US 1954189A US 407561 A US407561 A US 407561A US 40756129 A US40756129 A US 40756129A US 1954189 A US1954189 A US 1954189A
- Authority
- US
- United States
- Prior art keywords
- tungsten
- wire
- cathode
- discharge tube
- filament
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J1/00—Details of electrodes, of magnetic control means, of screens, or of the mounting or spacing thereof, common to two or more basic types of discharge tubes or lamps
- H01J1/02—Main electrodes
- H01J1/13—Solid thermionic cathodes
- H01J1/14—Solid thermionic cathodes characterised by the material
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/12—All metal or with adjacent metals
- Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
- Y10T428/12535—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.] with additional, spatially distinct nonmetal component
- Y10T428/12611—Oxide-containing component
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/12—All metal or with adjacent metals
- Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
- Y10T428/12771—Transition metal-base component
- Y10T428/12806—Refractory [Group IVB, VB, or VIB] metal-base component
- Y10T428/12826—Group VIB metal-base component
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/12—All metal or with adjacent metals
- Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
- Y10T428/12771—Transition metal-base component
- Y10T428/12806—Refractory [Group IVB, VB, or VIB] metal-base component
- Y10T428/12826—Group VIB metal-base component
- Y10T428/1284—W-base component
Definitions
- tungsten filaments become brittle so that their mechanical strength is materially decreased and their mounting in the discharge tubes is rendered very difiicult.
- the said disadvantages are obviated when the filament which is enclosed in the said discharge tube is not entirely of tungsten but consists of a body having a sheath of tungsten.
- the core of the filament contains molybdenum and the filament may be coated at least partially with a substance of high electronic emission.
- the core of the filament may 5 contain an oxide of thorium or of another material of high electronic emission.
- a sufiiciently strong filament body may be obtained by a suitable choice of the material of which the core of the filament is constituted and of the thickness of the tungsten sheath.
- the thickness of the tungsten sheath is less than 15% of the thickness of the filament, say
- a material may be taken which becomes brittle at a higher temperature than tungsten, for example a molybdenum wire which may have a diameter of 1500s.
- This wire is coated with a film of tungsten, for example,
- This operation of coating with tungsten may be effected by heating the molybdenum wire to say 1700 C. in an 9 atmosphere which contains a volatile tungsten compound, for example, an atmosphere which contains tungsten hexachloride.
- the sheath wire thus produced may be drawn down into a wire of smaller diameter. It is preferable that the drawn wire before being subjected to further handlings should be examined by immersion in a liquid which attacks the material of which the core is constituted but which does not attack tungsten. The points at which the core material is not covered with tungsten can thus be rendered visible so that it may be ascertained to which extent the core material is coated with tungsten.
- the wire may be immersed, for example, in a mixture of concentrated sulfuric acid and strong nitric acid.
- a filament produced in the manner described can be heated to a higher temperature than a filament entirely composed of tungsten without its mechanical strength being materially lowered.
- the body can be deprived of occluded gases prior to its being mounted in a discharge tube without becoming brittle and can be subjected without difficulty to the necessary deformations.
- the filament can be coated in any known I manner with a substance of high electronic emission, for example, with an earth alkaline metal or an earth alkaline metal oxide and is thus adapted to be used as a Wehnelt cathode.
- the earth alkaline metal may be precipitated, for example, on the filament from the vapour which may be developed in the tube by decomposition of an earth alkaline metal compound which consists, for example, of barium azide and which is mounted in the tube, for example, on an anode.
- a further material, for example copper may be mounted between the tungsten sheath and the electron emitting substance.
- the filament thus produced and used as an incandescent cathode is found to disintegrate to a much smaller extent than a filament which is not provided with a tungsten sheath such, for example, as a thoriated molybdenum cathode, and the filament is less brittle than a thoriated tungsten cathode although it is possessed of a like emission and disintegration as the latter so that it may be substituted satisfactorily for the cathode of the well known Tungar rectifier.
- the filaments described may be used with advantage in discharge tubes filled with gas, for example, a rare gas.
- the tube illustrated in Figure 1 comprises a bulb 1 of glass or similar material, to which a stem 2 has been fused.
- This stem carries the electrodes of the tube consisting preferably of a cylindrical anode 3 of nickel or other metal and an electron emitting cathode 4.
- the anode is mounted upon the stem with the aid of the supporting wire 5, Whereas the cathode is supported by the wires 6 and'7.
- the cathode contains, as can be seen from Figure 2, a composite wire comprising a core 8 of molybdenum and a sheath 9 of tungsten.
- an electron emitting coating 10 consisting for instance of barium oxide is formed.
- An electric discharge tube free from occluded gases, comprising an envelope, an anode,
- said cathode comprising compound wire comprised of a core of molybdenum and a coating of tungsten substantially entirely covering said core, the thickness of said tungsten being less than approximately 15% of the thickness of said wire, and a coating of oxide on said Wire.
- An electric discharge tube free from occluded gases, comprising an envelope, an anode, and a cathode, said cathode comprising compound wire comprised of a core of molybdenum and a coating of tungsten substantially entirely covering said core, the thickness of said tungsten being approximately 15% of the thickness of said Wire, and a coating of oxide on said wire.
- a Wehnelt' cathode for an electric discharge tube comprising a molybdenum core, a coating of tungsten substantially covering said core, the thickness of said tungsten being less than approximately 15% of the thickness of said wire, and a coating of oxide on said wire, said cathode remaining ductile at the temperatures required for degassing as Well as at the operating temperatures of the cathode.
Landscapes
- Solid Thermionic Cathode (AREA)
- Vessels And Coating Films For Discharge Lamps (AREA)
- Discharge Lamp (AREA)
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
NL1954189X | 1928-11-30 |
Publications (1)
Publication Number | Publication Date |
---|---|
US1954189A true US1954189A (en) | 1934-04-10 |
Family
ID=19873363
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US407561A Expired - Lifetime US1954189A (en) | 1928-11-30 | 1929-11-15 | Electric discharge tube |
Country Status (5)
Country | Link |
---|---|
US (1) | US1954189A (de) |
BE (1) | BE365560A (de) |
DE (1) | DE516901C (de) |
FR (1) | FR685521A (de) |
NL (1) | NL28872C (de) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3041209A (en) * | 1955-06-28 | 1962-06-26 | Gen Electric | Method of making a thermionic cathode |
US3066393A (en) * | 1958-02-17 | 1962-12-04 | Allegheny Ludlum Steel | Metal clad molybdenum article |
US5288561A (en) * | 1990-10-30 | 1994-02-22 | Kabushiki Kaisha Toshiba | High temperature heat-treating jig |
-
0
- BE BE365560D patent/BE365560A/xx unknown
- NL NL28872D patent/NL28872C/xx active
-
1929
- 1929-11-15 US US407561A patent/US1954189A/en not_active Expired - Lifetime
- 1929-11-22 DE DEN31193D patent/DE516901C/de not_active Expired
- 1929-11-25 FR FR685521D patent/FR685521A/fr not_active Expired
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3041209A (en) * | 1955-06-28 | 1962-06-26 | Gen Electric | Method of making a thermionic cathode |
US3066393A (en) * | 1958-02-17 | 1962-12-04 | Allegheny Ludlum Steel | Metal clad molybdenum article |
US5288561A (en) * | 1990-10-30 | 1994-02-22 | Kabushiki Kaisha Toshiba | High temperature heat-treating jig |
US5370837A (en) * | 1990-10-30 | 1994-12-06 | Kabushiki Kaisha Toshiba | High temperature heat-treating jig |
Also Published As
Publication number | Publication date |
---|---|
DE516901C (de) | 1931-01-28 |
FR685521A (fr) | 1930-07-11 |
NL28872C (de) | |
BE365560A (de) |
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