| 210 / | HD | LIQUID PURIFICATION OR SEPARATION |
| 348 | DF | FILTER {25} |
| 483 | DF | .~ Supported, shaped or superimposed formed mediums {11} |
| 488 | DF | .~.~ Abutted or superimposed members {2} |
| 489 | DF | .~.~.~ For series flow {1} |
| 490 | DF | .~.~.~.~ Integral or coated layers {1} |
| 491 | | .~.~.~.~.~ All fibrous |