US Patent 9068572 Centrifugal pump apparatus

This centrifugal blood pump apparatus includes an impeller provided in a blood chamber, a first permanent magnet provided in one surface of the impeller, and a second permanent magnet provided in an inner wall of the blood chamber, for attracting the first permanent magnet. The attractive force between the first permanent magnet and the second permanent magnet on the opening side of a sidewall of the blood chamber is set to be smaller than the attractive force between the first permanent magnet and the second permanent magnet on the opposite side of the opening. As a result, inclination of the impeller with respect to a dividing wall during pump operation can be prevented.