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:
Apr. 11, 1978
Filed:
Jul. 08, 1974
Applicant:
Inventors:
Assignee:
BBC Brown, Boveri & Company, Limited, Baden, CH;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H01B / ;
U.S. Cl.
CPC ...
252509 ; 252503 ; 252515 ; 252516 ; 3133 / ; 3133 / ; 252504 ;
Abstract
A thermionic cathode of tungsten or molybdenum is made with an activating content of lanthanum oxide and is supplied with a carbonaceous reducing agent either by incorporation in the bulk material of the cathode body or by carburizing, so that the reducing agent comprises at least in part a carbide of the carrier metal. Lower operating temperatures and higher emissivity are obtained compared to thoriated tungsten filaments and longer useful life compared to other cathodes activated by other rare earth oxides. The temperature-emissivity characteristics are such that good results are obtainable even within the temperature range in which molybdenum is usable as a carrier material.