Patent ID: 6011490
Filing Date: 2000-01-04
Classification: B04B,G01F,G01N

Abstract:
Apparatus for measurement of the position of an interface between two fluids in a centrifuge rotor (2) during rotation, comprising an electric or magnetic sensor (4) mounted internally on a wall in the centrifuge rotor (2), and means (5A,5B) for contact-free and intermittent transmission of measurement signals from the sensor (4) to a stationary measuring unit (7) outside the centrifuge rotor, characterized inthat the sensor (4) has such an extension in the radial direction of the rotor (2) that the sensor penetrates said interface,that the sensor (4) comprises an active electronic circuit (8) adapted to store measurement values that are recorded during at least a portion of a revolution of the rotor (2), before said transmission of corresponding measurement signals to the measuring unit (7), andthat electric power supply to the electronic circuit (8) is provided for by generator means comprising a stationary magnet (11) near the centrifuge rotor (2) and a coil (12) mounted in the rotor so that a voltage is induced in the coil (12) during movement past the magnet (11) by rotation of the rotor (2), and the coil (12) is connected to the electronic circuit (8).