Centrifugal fluid pump apparatus

A centrifugal fluid pump apparatus comprising a pump body in which an impeller rotates without contacting a housing;

• and a control mechanism for said pump body,
• said pump body including:
• said housing having a blood inlet port and a blood outlet port;
• a centrifugal pump section including an impeller having a first magnetic material and a second magnetic material and rotating in said housing to feed a fluid by a centrifugal force generated during its rotation;
• an impeller rotational torque generation section including a rotor having a magnet for attracting said first magnetic material of said impeller and a motor for rotating said rotor;
• an impeller position control section having an electromagnet for attracting said second magnetic material of said impeller;
• a position sensor for detecting a position of said impeller;
• and
• a groove for hydrodynamic bearing provided on an inner surface of said housing at a side of said rotor or on a surface of said impeller at a side of said rotor,
• said control mechanism comprising:
• a position sensor output monitoring function or an electromagnet current monitoring function;
• a motor current monitoring function;
• a failure detection function for determining a failure of the sensor by using said position sensor output monitoring function or a failure of the electromagnet by using said electromagnet current monitoring function;
• and
• an emergency impeller rotation function operating when said failure detection function detects the failure of the sensor or the failure of the electromagnet to rotate said impeller by utilizing said groove for hydrodynamic bearing without substantial contact between said impeller and said housing,
• wherein said emergency impeller rotation function has:
• an impeller magnetic re-coupling execution function of stopping said electromagnet from attracting said impeller, when said failure detection function detects said failure and gradually decreasing a motor speed to thereby execute magnetic coupling between said impeller and said rotor;
• a magnetic re-coupling detection function of detecting magnetic re-coupling between said impeller and said rotor by using a motor current monitored by said motor current monitoring function;
• and
• a motor speed control function by increasing the motor speed up to a predetermined value after said magnetic re-coupling detection function detects said magnetic re-coupling.