The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 07, 1989
Filed:
May. 08, 1987
Applicant:
Inventor:
David B Fox, Chelmsford, GB;
Assignee:
English Electric Valve Company Limited, Chelmsford, GB;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H01J / ;
U.S. Cl.
CPC ...
313342 ; 313341 ; 313345 ; 313352 ; 313254 ; 313 3963 ;
Abstract
A directly heated cathode comprises a metal tube having a filling of powdered metal which extends beyond the tube and in which is embedded an electrical wire which is coaxial and extensive with said the outer tube over part of its length. The electrical wire is coated with insulating material which is normally alumina. The tube, the metal powder filling and the wire are sintered together, giving a relatively robust structure.