Patent ID: 7470246

Claim:
A centrifugal blood pump apparatus comprising: a housing having a fluid inlet port and a fluid outlet port; a centrifugal pump section including an impeller having a first magnetic material therein and rotatable inside said housing to feed a fluid by a centrifugal force generated during a rotation thereof; an impeller rotational torque generation section for attracting and rotating said impeller; and a hydrodynamic pressure groove formed at a portion of an inner surface of said housing at an impeller rotational torque generation section side or at a portion of a surface of said impeller at said impeller rotational torque generation section side, said impeller being rotatable without contacting said housing owing to an action of said hydrodynamic groove, an electromagnet for attracting said first magnetic material of said impeller or a second magnetic material provided on said impeller separately from said first magnetic material in a direction opposite to a direction in which said impeller rotational torque generation section attracts said first magnetic material and helping said impeller levitate; a control mechanism for controlling said impeller rotational torque generating section and said electromagnet, said control mechanism starting rotation of said impeller rotational torque generating section with said electromagnet attracting said impeller thereto at a force not less than a predetermined value; and wherein said impeller rotational torque generation section has a rotor having a magnet for attracting said first magnetic material of said impeller and a motor for rotating said rotor; and said hydrodynamic pressure groove formed at the portion of the inner surface of said housing at a rotor-disposed side or the portion of the surface of said impeller at said rotor-disposed side, and said electromagnet attracting said first magnetic material or the second magnetic material in a direction opposite to the direction in which said magnet of said rotor attracts said first magnetic material to help said impeller levitate.