Patent ID: 8957674
Filing Date: 2015-02-17
Classification: F04B,G01F

Abstract:
1. A pump comprising an electrical motor drive ( 2 ) and a pump engine ( 3 ), the pump engine having a stator portion ( 32 ) and an axially and rotatably movable rotor portion ( 30 ) mounted in the stator portion and having an inlet and an outlet, the electrical motor drive comprising a rotor ( 6 ) with a permanent magnet ( 20 ), a stator ( 4 ) with a magnetic circuit ( 10 ) and one or more coils ( 18 ), and a position sensor ( 8 ) comprising at least a pair of magnetic field detectors ( 24 a , 24 h ) positioned in the proximity of the rotor permanent magnet opposite an axial end ( 36 ) of the rotor permanent magnet and configured such that the signal phase offset between the pair of magnetic field detectors is 90° to detect both rotational and axial movement of the rotor.