| 416 / | HD | FLUID REACTION SURFACES (I.E., IMPELLERS) |
| 120 | DF | PLURAL IMPELLERS HAVING RELATIVE MOVEMENT OR INDEPENDENT SUPPORTS {5} |
| 124 | | .~ Coaxial rotation {4} |
| 125 | DF | .~.~> Individual prime mover |
| 126 | DF | .~.~> Concentric working members |
| 127 | DF | .~.~> Concurrent adjustment |
| 128 | DF | .~.~> Oppositely rotating impellers {1} |