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Abstract: Magnetic bearing has no mechanical contact between the
rotor and stator, and a rotary pump with magnetic bearing has therefore
no mechanical wear and thrombosis. The available magnetic bearings,
however, are devised with electric magnets, need complicated control and
remarkable energy consumption. Consequently, it is difficult to apply an
electric magnetic bearing to rotary pump, without affecting its
simplicity, implantability and reliability. The author has developed a
levitated impeller pump merely with permanent magnets. The rotor is
supported by permanent magnetic forces radially. On one side of the
rotor, the impeller is fixed; and on the other side of the rotor, the
rotor magnets are mounted. Opposite to this rotor magnets, a driving
magnets is fastened on the motor axis. Thereafter, the motor drives the
rotor via magnetic coupling. In laboratory tests with saline, in case
the rotor keeps still or rotates under 4 000 r/min, the rotor magnets
have one-point contact axially with a spacer between the rotor magnets
and the driving magnets. The contacting point is located in the center
of the rotor. As the rotating speed increases gradually to over 4 000
r/min, the rotor will disaffiliate from the stator axially. Then the
rotor will be fully levitated. Since the axial levitation is produced by
hydraulic force and the rotor magnets have a gyro-effect, the rotor
rotates very stably during levitation. As a left ventricular assist
device, the pump works in a rotating speed range of 5 000~8 000 r/min,
and the levitation of the impeller, hence, is assured by the practical
use of the pump. The permanent maglev impeller pump retains the
advantages of rotary pump but overcomes the disadvantages of the
levitated pump with electric magnetic-bearing, and has actually met
most of requirements of artificial heart blood pump, thus promises to be
able to replace the donor heart for transplantation and to support the
failing heart permanently.
Key words: Magnetic bearing Gyro-effect Centrifugal pump Blood pump
CLC No: R318.11
国家自然科学基金资助项目(39970736).
Received 20001218, received in revised form 20010608
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