Serum/plasma separator with centrifugal valve

Claim 1

A separator device for separating mixed light phase and heavy phase constituents of blood and establishing a permanent barrier between said phases, including: a tubular container closed at both ends, one of said ends being closed with a stopper penetrable by a needle for the introduction of blood into said container; elastomeric barrier means fixedly located intermediate the container ends and dividing the container into first and second chambers such that upon separation of the blood into the light phase and the heavy phase by the application of centrifugal force, the first chamber contains only the light phase; a passageway through the barrier means connecting the first and second chambers; a ball in said first chamber having a specific gravity greater than the heavy phase of the blood; and a stretchable diaphragm integral with the base of the barrier means and extending across the passageway, at least one normally closed aperture in the diaphragm, the diaphragm normally sealing off the passageway to provide a barrier between first and second chambers, and when subjected to a predetermined centrifugal force, the ball causes the diaphragm to stretch in the direction of the second chamber to open the apertures to provide communication between the chambers to permit the light phase to travel to the first chamber and the heavy phase to travel to the second chamber, and upon cessation of the applied centrifugal force, the diaphragm returns to its normal unstretched position to close the apertures and seal off the passageway and provide a barrier between the first and second chambers; said ball normally resting on the upper surface of said diaphragm.