A NEW ELECTROHYDRAULIC ENERGY CONVERTER FOR A LEFT-VENTRICULAR ASSISTDEVICE

An energy converting system that can function for years without mainte nance is required for the drive of a left ventricular assist device (L VAD). To meet the requirements of safety, the energy converter should have a simple design with few moving elements. The design applied here in has only one moving part and thus has greater inherent safety than competing systems. The only moving part is the rotor unit, comprised o f the impeller of a centrifugal pump, the rotor of an electric motor, and the rotor of an electric axial actuator. A reversal of flow of the transmitter fluid can be achieved with an axial shift of this rotor u nit. This fluid acts on the outer surface of a blood chamber and enabl es it to draw in blood and to expel it. Valves direct the flow of bloo d. The energy converter performs a flow of 12 L/min at a motor speed o f 6,000 rpm against a pressure head of 115 mm Hg according to an outpu t of the pulsatile blood pump of 5 L/min.