Cost-effective Magnetic Bearing System Using a Single-Use Magnet-Less Rotor for an Extracorporeal Centrifugal Blood Pump

In the field of rotary blood pumps, contactless support of an impeller by a magnetic bearing has been identified as a promising method to reduce blood damage and enhance the durability. We have developed a two-degrees-of-freedom controlled magnetic bearing system without any permanent magnet in the impeller, so that a single-use pump head of an extracorporeal centrifugal blood pump could be manufactured more easily at a low cost. A prototype blood pump with the magnetic bearing realized stable levitation and contactless rotation of the impeller. The run-out of the impeller position from 1,000 rpm to 3,000 rpm was less than 70 µm (3?) in the radial controlled directions. The total power consumption of the magnetic bearing was less than 1 W at the same rotational speeds. The pump could yield a flow rate of 5 L/min against a head pressure of 590 mmHg (78.7 kPa) at the speed of 4,000 rpm, which provided sufficient performance for an extracorporeal circulation support.