(under subclass 200) Subject matter wherein particular significance is attributed to a configuration which prevents or reduces unwanted sound.
(1) Note. See the Search Class notes below for references to
the line between Class 454 and other classes.
SEE OR SEARCH THIS CLASS, SUBCLASS:
262, for an inlet airway, including structure for mixing plural airstreams together, which has specific noise inhibiting structure.
346, for an outlet airway having vibration absorbing or preventing structure.
906, for a cross-reference art collection of ventilating structure combined with noise inhibiting means.
SEE OR SEARCH CLASS 181, Acoustics, appropriate subclasses. Note particularly
212+, for a fluid conducting-type sound muffler of a general nature, and see subclass 212, (1) Note, for the line between Class 181 and this class (454); and subclass 224 for a sound absorbing ventilating duct.
