Centrifuge assembly

Abstract

An improved centrifuge assembly comprising a channeled rotor assembly and a fluid container disposed in the channel, whereby the centrifugal separation effects in the fluid container are determined by the geometry of the channel in the rotor. This arrangement is particularly useful for two-stage blood platelet separation. The fluid container is preferably formed from semirigid plastic material and is considered a disposable item to be discarded after a single use. The rotary assembly preferably includes a removable filler piece or center piece formed from a single piece of material, such as rigid plastic, as by machining or molding, and having therein an open-topped channel having dimensions appropriate to receive the semirigid container, which is suitably curved and placed in the channel. Fluid connections are provided from each end of the container and an intermediate point to an axially located multichannel rotating seal. The connections lie in a plurality of radial slots in the filler piece. The channel is divided into two distinct portions, the first portion of the channel being circular with a constant radius, and the second portion being spiral and having a plurality of radiuses, each measured from a different center, the spiral increasing radially outward from its juncture with the first stage. The intermediate fluid connection is established near the junction of the first stage and the second stage. The spiral portion of the channel and container may have an outward slope from bottom to top.