Abstract: A pump especially suited for pumping a saturated liquid while employing motive power from a high speed rotor. The disclosed pump comprises a stationary, generally cylindrical inner wall on which is mounted a sleeve member defining a generally cylindrical outer wall radially spaced from the inner wall to define an elongated annular chamber. The outer wall is mounted for rotation relative to the inner wall and at one end of the annular chamber there is a rotarty impeller which rotates relative to the inner wall to direct fluid radially outwardly from adjacent the surface of the outer wall. Fluid supply inlet openings are provided to supply fluid through the inner wall to the annular chamber at a position axially spaced from the impeller. A vapor discharge outlet is carried by the sleeve member and provided with an inlet adjacent the inner wall at a location spaced from the fluid inlet in a direction opposite the impeller.