US PATENT SUBCLASS 454 / 232
.~.~ Having plural or branched recirculation ducts

Current as of: June, 1999
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454 /   HD   VENTILATION

228  DF  HAVING FORCED RECIRCULATION {4}
230  DF  .~ Forced recirculation alone {3}
232.~.~ Having plural or branched recirculation ducts

DEFINITION

Classification: 454/232

Having plural or branched recirculation ducts:

(under subclass 230) Subject matter comprising two or more conduits for separately guiding air between locations within the ventilated space.

(1) Note. A single conduit comprising plural sections connected in series is not included in this subclass.