(under subclass 1) Subject matter comprising a surface within the vertical conduit section which straightens or diverts flow of air or products of combustion through the conduit.
(1) Note. A mere vertical conduit wall is not considered to be an internal current guide. Particular flow guiding wall structure must be claimed for inclusion in this subclass.
SEE OR SEARCH CLASS
126, Stoves and Furnaces,
285+, for chimney or stack dampers, per se, not incorporated in chimneytop or stacktop structure.
