(under subclass 120) Apparatus wherein the support for at least one of the impellers is movable as a whole to a different operative position relative to (1) at least one other impeller or (2) a common support for the plural impellers (e.g., vehicle body).
(1) Note. The movement does not include that relative movement of a support which is inseparable from normal impeller operation (e.g., reciprocating or eccentric shaft), nor is a mere mounting adjustment or tiltable carrier* included.
