Patent ID: 8177072

Claim:
A device for separating and isolating components of a biological fluid with centrifugation, said device comprising: an enclosure comprising an interior circumferential surface defining a chamber for containing a biological fluid having multiple components; a float slideably disposed within said enclosure and partitioning said enclosure into a lower volume zone and an upper volume zone; said float comprising an interior isolation chamber defining an intermediate volume zone and an exterior circumferential surface circumferentially spaced from said interior circumferential surface of said enclosure for defining a circumferential gap therebetween; a first valve means for opening and closing communication of biological fluid from said upper volume zone to said interior isolation chamber within said float; and a second valve means for opening and closing communication of biological fluid from said interior isolation chamber within said float to said lower volume zone of said container wherein under centrifugation said first valve means and said second valve means control at least one closed loop circulation of biological fluid into said interior isolation chamber from said upper volume zone, out of said interior isolation chamber into said lower volume zone, out of said lower volume zone and through said circumferential gap to said upper, volume zone, and back into said interior isolation chamber as a function of a first pressure differential of biological fluid on said first valve means and as a function of a second pressure differential of biological fluid on said second valve means for isolating at least one target component of the multiple component biological fluid within said interior isolation chamber of said float.