| 55 / | HD | GAS SEPARATION |
| 315 | DF | PLURAL SERIAL BASICALLY DIVERSE SEPARATING MEDIA {3} |
| 318 | DF | .~ Plural stages in unitary casing {2} |
| 320 | DF | .~.~ Deflector and fibrous, filamentary, particulate solids, or cohesive sheet filter type {6} |
| 328 | ![]() | .~.~.~ Movable or movable mounted for adjustment or nonuse |