(under subclass 11) Devices which are provided with a filament, a directly heated cathode or an indirectly heated cathode and which include means to modify the temperature of the filament or cathode.
(1) Note. The structure must include more than a filament, a directly heated cathode or an indirectly heated cathode. For example, included in this and the indented subclass are devices in which a heat conserving shield is placed about the cathode to conserve the heat of the cathode and devices which have means to conduct heat from a portion of the cathode so as to reduce the temperature of the cathode portion.
SEE OR SEARCH THIS CLASS, SUBCLASS:
39+, for other devices under subclass 11 which are provided with a cathode which may be a thermionic cathode other than a directly or indirectly heated cathode and which includes means to modify the temperature of the cathode.
337+, for the structures of indirectly heated cathodes, per se.
341+, for the structure of filaments and directly heated cathodes. 346, for the structure of thermionic cathodes.
