A pump drive unit has an openable housing that accommodates a disposable impeller unit which is pre-connected with tubing, while maintaining the tight tolerances and close spacing. A levitation system (magnets and sensors), drive motor and drive magnets, and control electronics are all re-usable and housed within relatively permanent structures. In one embodiment, a hinged top separates the levitating magnets to allow the impeller unit to be captured and retained with positional accuracy and in close proximity to the desired locations when the hinged top is closed. The top may be separated into sections covering unequal arcs to coincide with the organization of the magnetic subcomponents in the upper drive unit housing.