(under subclass 360) Subject matter comprising the structure of headers of the drum type and tube connections therefor and closures for the drum hand holes when the drum structure is involved.
SEE OR SEARCH THIS CLASS, SUBCLASS:
365, for general structure of drums for water tube boilers.
393, for the structure of mud drums and modifications in boilers for their application.
SEE OR SEARCH CLASS
220, Receptacles, 200+, for closures of general application.
