Abstract: A method and system of identifying a rotor of a centrifuge employ an approach that uses two tiers of model selection. Firstly, the moment of inertia of a rotor is calculated for a first measured acceleration. The indication of moment of inertia is utilized to disqualify a number of rotor models and to select a subset of models. In a second tier, windage power of the rotor is calculated in a manner that isolates windage from inertial drag. In one embodiment, drive torque is measured with the rotor operated at a high constant speed. Alternatively, windage is calculated using data obtained during a second measured acceleration. The accuracy of the computation is enhanced by taking into account the moment of inertia as one form of resistance to the second acceleration. Based upon the indication of windage power, at least one rotor model within the subset is disqualified. Upon identification of the rotor, the centrifugal process can be maintained at a maximum safe speed.

Abstract: A method and system of determining an operation parameter for a centrifuge includes measuring one or more physical characteristics of a rotor interchangeably supported by a rotor drive. In the preferred embodiment, windage is measured at a first rotational speed and a speed-dependent signal is generated to adjust a vacuum system based upon changes in rotational speed of the rotor. Changes in windage may also be used as a basis for adjusting a refrigeration circuit. Either as an alternative or in addition to monitoring windage, the moment of inertia can be measured and used to adjust adaptive circuitry. For example, the drive circuitry may be adjusted based upon a determination of inertia as the physical characteristic of interest. The method and system isolate inertia and windage as the main forms of resistance to acceleration of the rotor.

Abstract: A device for centrifugally separating a sample includes a housing which defines an enclosed chamber from which gas is evacuated via an evacuation port protected by a spinning rotor. The evacuation port is preferably located proximate to the axis of rotation of the rotor and within the interior of the rotor. A drive shaft connects the rotor to a motor positioned outside of the chamber. An annular sleeve having an inside diameter greater than the diameter of the shaft extends coaxially along the drive shaft into the chamber. The outlet of the gap between the drive shaft and the annular sleeve defines the evacuation port. A hub is fixed to the upper end of the drive shaft and includes a downwardly depending skirt that has an inside diameter greater than the outside diameter of the annular sleeve. Gas evacuation from the chamber is initially in an upward direction along the gap between the hub skirt and the sleeve and in a downward direction from the evacuation port to a vacuum pump.