Abstract: A centrifuge has a rotor for receiving a disposable processing unit. The centrifuge is configured such that the motor is attached to an enclosure and the enclosure is supported on a base. The connection between the base and the enclosure is a vibration isolator, and the isolator is positioned such that its effective line of action aligns with the effective plane of rotation of the rotor. In accordance with another feature of the invention, the processing units are held in a decanting position by a decant ring that moves vertically but does not rotate. The ring engages the top of the processing unit during decant and the abrasion is minimal.