| 摘要 |
A blood pump 51 for assisting a heart is provided by a stator and a rotor. The rotor is rotated relative to the stator by a motor. The blood pump apparatus includes a flow rate controller 92 and a flow rate sensor 91 to avoid excessively low or reverse flow through the pump when a pulsatile flow rate is provided. The flow rate controller may include a heart caliper 400/500 for measuring the dimension of a heart ventricle to control the flow rate to avoid overly distending or contracting the ventricle. The caliper 400/500 comprises two caliper arms positioned at opposing sides of the ventricle. Measurement of the ventricle dimension may be achieved by an angular measurement device measuring changes in the angle between the arms (fig 9) or by a pair of ultrasonic transducers located at opposite sides of the ventricle (504, 505, figs 10a and 10b). The motor for the pump may comprise a magnetic drive comprising a permanent magnet (31 fig 1a) armature windings (32, fig 1a) and back-iron (33, fig 1a). The rotor may be suspended in the stator by a magnetic suspension comprising two permanent magnet arrays (11, 12 fig 1a). The rotor may be axially supported by a Lorentz-force bearing (13-18, fig 1a). The pump may also include an axial position actuator engaged with the stator or rotor to permit the axial alignment between the stator and rotor to be adjusted.
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