Abstract: A fluid power system comprising a fluid pump and an impulse turbine operating in the incompressible domain wherein the pump is characterized by a pressure versus flow curve that is inversely interdependent and by a predetermined pump optimum flow area that is associated with maximum pump output power and the turbine includes an inlet flow path to the turbine rotor the effective area of which is substantially matched to the pump optimum flow area to constrain pump operation to the region of maximum output power.

Abstract: The vacuum generating system for a hand-held vacuum cleaner comprises a fan or impeller having backwardly curved arcuate blades extending between preferably frusto-conical wall portions of front and rear fan shrouds. The front fan shroud is associated with the fan housing to provide a slip seal against vacuum loss around the sides of the fan. The centers of curvature of the arcuate blades are parallel to the central axis of the fan. Although the air flow passages defined by the blades and front and rear shrouds are of complex shapes, the fan may be manufactured economically. The air watts performance curve of the fan is desirably blunted or flattened without significant reduction of altitude or maximum height as compared to prior cleaners.