K-series centrifuges. II. Performance of the K-II rotor.

The K-II centrifuge (1-3) was designed for large-scale virus isolation using the continuous-sample-flow-with-banding technique (CFB) (4--8), and has been used successfully for the commercial production of influenza vaccine (9, 10). The rotor was originally designed for dynamic unloading; however, the resolution obtained was less than expected. The gradient has therefore been allowed to reorient (11, 12) during deceleration to the configuration obtained at rest, and the rotor contents recovered. The over-all configuration with a tapered core employed for dynamic unloading was retained, however. In this paper, results of studies, largely with polystyrene beads as model particles, are described, together with data on loss of gradient solutes during continuous flow through the rotor. The results indicate that loss of resolution during reorientation is surprisingly small.