GB397656A - Improvements in the manufacture of thermionic cathodes for electric discharge devices - Google Patents
Improvements in the manufacture of thermionic cathodes for electric discharge devicesInfo
- Publication number
- GB397656A GB397656A GB20729/32A GB2072932A GB397656A GB 397656 A GB397656 A GB 397656A GB 20729/32 A GB20729/32 A GB 20729/32A GB 2072932 A GB2072932 A GB 2072932A GB 397656 A GB397656 A GB 397656A
- Authority
- GB
- United Kingdom
- Prior art keywords
- peroxide
- minutes
- tungsten
- during
- period
- 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
Links
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J9/00—Apparatus or processes specially adapted for the manufacture, installation, removal, maintenance of electric discharge tubes, discharge lamps, or parts thereof; Recovery of material from discharge tubes or lamps
- H01J9/02—Manufacture of electrodes or electrode systems
- H01J9/04—Manufacture of electrodes or electrode systems of thermionic cathodes
- H01J9/042—Manufacture, activation of the emissive part
Landscapes
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Discharge Lamp (AREA)
- Solid Thermionic Cathode (AREA)
Abstract
397,656. Thermionic cathodes. GENERAL ELECTRIC CO., Ltd., Magnet House, Kingsway, London, and RANDALL, J. T., c/o General Electric Co., Wembley, Middlesex. July 22, 1932, No. 20729. [Class 39 (i).] Thermionic cathodes, particularly for discharge lamps, of the type consisting of a selfsupporting mass heated by means, for example a tungsten spiral, which do not contribute to the rigidity of the mass, are prepared by forming a mass of the desired shape out of alkaline earth peroxide and decomposing the peroxide by heat. Metal, particularly tungsten, powder, may be mixed with the peroxide. The peroxide may be bound with a 10 per cent solution of nitro-cellulose in amyl acetate, in the proportion 20 grams of barium peroxide to 4 to 5 grams of the binder. Gum tragacanth is not suitable. In one example the mixture is squirted into rods 4À5 mm. in diameter, and heated in a vacuum furnace. The temperature is raised to 125‹ C. during a period of 30 minutes, then from 125‹ C. to 250‹ C. during a further period of 30 minutes ; this decomposes the binder. The temperature is then raised to 1150‹ C. during a period of 90 minutes, whereby the peroxide is decomposed. To sinter the rods they are placed in a molybdenum boat lined with tungsten in a hydrogen-filled furnace and the temperature is raised to 1620‹ C. during a period of 30 minutes and held there for 10 minutes. A magnesia lining may be used instead of tungsten.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB20729/32A GB397656A (en) | 1932-07-22 | 1932-07-22 | Improvements in the manufacture of thermionic cathodes for electric discharge devices |
| US678989A US1990204A (en) | 1932-07-22 | 1933-07-03 | Manufacture of thermionic cathodes for electric discharge devices |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB20729/32A GB397656A (en) | 1932-07-22 | 1932-07-22 | Improvements in the manufacture of thermionic cathodes for electric discharge devices |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB397656A true GB397656A (en) | 1933-08-31 |
Family
ID=10150676
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB20729/32A Expired GB397656A (en) | 1932-07-22 | 1932-07-22 | Improvements in the manufacture of thermionic cathodes for electric discharge devices |
Country Status (2)
| Country | Link |
|---|---|
| US (1) | US1990204A (en) |
| GB (1) | GB397656A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2845515A (en) * | 1953-03-12 | 1958-07-29 | Raytheon Mfg Co | Semimetallic resistive filaments |
| GB0128405D0 (en) * | 2001-11-27 | 2002-01-16 | Btg Int Ltd | Process for fabricating polyolefin sheet |
-
1932
- 1932-07-22 GB GB20729/32A patent/GB397656A/en not_active Expired
-
1933
- 1933-07-03 US US678989A patent/US1990204A/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| US1990204A (en) | 1935-02-05 |
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