A pump features a two-part axial flow shaft having a static inner shaft portion and a rotating outer shaft portion; the static inner shaft portion having static diffuser vanes, and also having two shaft ends configured to affix to a frame of a pump so the static inner shaft portion does not rotate; and the rotating outer shaft portion having an outer portion configured to affix to a rotor of the pump to rotate the rotating outer shaft portion, also having rotating impeller vanes configured inside and coupled to the outer portion to move the fluid axially along the two-part axial flow shaft as the rotating outer shaft portion axially rotates in relation to the static inner shaft portion.