Abstract: A centrifugal separator capable of selectively mounting sedimentation tubes or capillary tubes on a rotor includes a container receptacle mounted in an outer box of the separator for receiving sedimentation tube containers. When the sedimentation tube containers are received in the container receptacle, their presence is detected to enable the rotor to rotate at a relatively high speed required when the capillary tubes mounted on the rotor.

Abstract: A rotor for a centrifuge comprises a rotatable shaft, a disc-shaped bottom plate fixed to the rotatable shaft, and a holder plate mounted on the bottom plate for holding sedimentation tubes. The holder plate is bodily constructed of a thin plate and has a bent portion positioned between a center and outer edge thereof and projecting upwardly. The bent portion includes a surface directed toward the center of the holder plate and having a plurality of holes for insertion therethrough of the sedimentation tubes. The bottom plate has a plurality of holes aligned with the holes in the holder plate for receiving the sedimentation tubes therein.