(under subclass 334) Fluid handling systems in which (1) air as a heating or cooling fluid for the system has a thermally caused movement through channels whereby it is warmed by contact with the earth and/or an object buried in the earth, such as a pipe line; or (2) the fluent material system or a part thereof is equipped with a fan or fins to aid in the heating or cooling of the device or the fluid by heat exchange with the air.
SEE OR SEARCH THIS CLASS, SUBCLASS:
564, for distribution systems involving closed circulating systems of the thermal type.
SEE OR SEARCH CLASS
123, Internal-Combustion Engines,
41, and 52.1+ for air cooled internal combustion engines.
