http://rdf.ncbi.nlm.nih.gov/pubchem/patent/GB-308217-A
Outgoing Links
| Predicate | Object |
|---|---|
| classificationCPCInventive | http://rdf.ncbi.nlm.nih.gov/pubchem/patentcpc/H01J9-04 |
| classificationIPCInventive | http://rdf.ncbi.nlm.nih.gov/pubchem/patentipc/H01J9-04 |
| filingDate | 1929-03-18-04:00^^<http://www.w3.org/2001/XMLSchema#date> |
| publicationDate | 1930-07-18-04:00^^<http://www.w3.org/2001/XMLSchema#date> |
| publicationNumber | GB-308217-A |
| abstract | 308,217. Loewe, B. March 19, 1928, [Convention date]. Vacuum tubes.-In indirectly-heated cathodes adapted to be energized from supply mains, the heating filament is coated with a semi-conductive layer by means of chemical action by covering the filament with a semi-liquid mass of barium oxide and silicon, the proportions being 3 grams of oxide and 0.3 of silicon. Alternatively, the filament is coated with a powdered mixture of these materials which is melted by heating the filament. After evacuation of the valve, the filament is heated to beyond 1200‹ C. and the metallic barium evolved is deposited on the anode, the fused layer on the filament constituting the required semi-conductive layer. The valve is then opened under oil, the heating element detached, the oil removed and a metallic equipotential layer formed thereon from a solution of platinum, gold or silver &c. in organic solvents which is deposited thereon, dried and ignited. Alternatively, the metallic coating may be formed by heating in nickel carbonyl. After reassembly and evacuation, the cathode is activated by heating the anode to cause the barium to be deposited on the cathode the,protective coating of oil having been first driven off. The Specification as open to inspection under Sect. 91 (3) (a) states also that the insulating body is attached directly to the heating filament or this mav be coated with an adhesive insulating paste which is finally provided with a metallic deposit by precipitation etc.; the insulating body may be surrounded by a metal sheet or tube. As insulating material, a paste of zirconium oxide and starch, water-glass or colloidal silicic acid is spread on the heating body, dried and burnt. Oxides of aluminium, magnesium, calcium, barium or strontium may replace zirconia. For securing the leads to the metallic coating, a mixture of equal parts of copper and lead borate is heated in a reducing flame. Nickel, platinum,. gold or silver may replace the copper in this mixture. Highly emissive materials are finally deposited on the metallic coating. In a modified method of producing the insulating layer, tungsten, platinum &c. wire is heated in an atmosphere of chromyl chloride or the filament is coated with ammonium bichromate and heated. The ends of the filament may be protected by means of sleeves which are slipped over them. This subject-matter does not appear in the Specification as accepted. |
| priorityDate | 1928-03-19-04:00^^<http://www.w3.org/2001/XMLSchema#date> |
| type | http://data.epo.org/linked-data/def/patent/Publication |
Incoming Links
Total number of triples: 43.