Gyro-effect stabilizes unstable permanent maglev centrifugal pump.

Full Abstract

According to Earnshaw's Theorem (1839), the passive maglev cannot achieve stable equilibrium and thus an extra coil is needed to make the rotor electrically levitated in a heart pump. The author had developed a permanent maglev centrifugal pump utilizing only passive magnetic bearings, to keep the advantages but to avoid the disadvantages of the electric maglev pumps. The equilibrium stability was achieved by use of so-called "gyro-effect":
a rotating body with certain high speed can maintain its rotation stably. This pump consisted of a rotor (driven magnets and an impeller), and a stator with motor coil and pump housing. Two passive magnetic bearings between rotor and stator were devised to counteract the attractive force between the motor coil iron core and the rotor driven magnets. Bench testing with saline demonstrated a levitated rotor under preconditions of higher than 3,250 rpm rotation and more than 1 l/min pumping flow. Rotor levitation was demonstrated by 4 Hall sensors on the stator, with evidence of reduced maximal eccentric distance from 0.15 mm to 0.07 mm. The maximal rotor vibration amplitude was 0.06 mm in a gap of 0.15 mm between rotor and stator. It concluded that Gyro-effect can help passive maglev bearings to achieve stabilization of permanent maglev pump; and that high flow rate indicates good hydraulic property of the pump, which helps also the stability of passive maglev pump.

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Author information

Author/s: Qian, Kun-Xi (KX);

Affiliation: Biomedical Engineering Institute, Jiang-su University, Zhenjiang, China. swyx(-atsign-)ujs.edu.cn

Journal and publication information

Publication Type: Journal Article

Journal: Cardiovascular engineering (Dordrecht, Netherlands) (Cardiovasc Eng), published in Netherlands. (Language: eng)

Reference: 2007-Mar; vol 7 (issue 1) : pp 39-42

Dates: Created 2007/04/12; Completed 2007/08/28;

PMID: 17380386, status: MEDLINE (last retrieval date: 12/26/2008)

Sourced from the National Library of Medicine. Abstract text and other information may be subject to copyright.

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MeSH headings (categories)

This article was linked to the MESH Headings shown below.

Centrifugation - instrumentation
Computer-Aided Design
Equipment Design

Equipment Failure Analysis
Heart-Assist Devices
Magnetics - instrumentation; therapeutic use

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