Device for separating the components of a liquid sample having higher and lower specific gravities

DETAILED DESCRIPTION OF THE INVENTION Referring to the drawings in which like reference characters refer to like parts throughout the several views thereof, FIG.
1 illustrates the invention in the form of a serum separation tube having a closed end and an open end with the latter being arranged to be sealed by a cooperating stopper so as to maintain a vacuum in the tube once the stopper is in place.
In FIG.
1, the assembly of the invention generally designated 10 includes tube 12 having an open end 14 and a closed end 16.
Tube 12 is transparent so that the user may readily observe what is going on with the contents thereof.
Tube 12 may be plastic but it is preferably glass.
Elastomeric stopper 20 is provided for insertion into the open end 14 of tube 12.
Stopper 20 includes an upper annular portion 22 and a lower annular portion 26 of lesser diameter, with the lower portion 26 being arranged to be inserted into tube 12 so that the internal surface 32 of tube 12 adheres to and seals against the external surface 30 of annular portion 26.
Because of the differing diameters of lower portion 26 and upper portion 22 of stopper 20, an annular ledge or abutment 24 is arranged to seat on the top surface of open end 14 of tube 12 to further enhance the sealing between tube 12 and stopper 20.
Stopper 20 further includes a vent 28 positioned at one point in the circumferential extent of the lower portion 26 of stopper 20.
The purpose of vent 28 will be described below.
Tube 12 may be open at both ends (not shown) with a stopper 20 inserted in each end.
Further shown in FIG.
1 is a dual separator assembly 34, including a molded solid core 36 and an elastomeric cup-shaped flexible component 38.
Solid core 36 nests in the cup-shaped elastomeric component 38.
These two parts form dual seals 60 and 70.
This is achieved by the annular ring portion 46 of solid core 36 cooperating with the upper annular ring portion 44 of the elastomeric cup-shaped lower portion 38.
Thus, surface 40 of portion 44 of the cup-shaped elastomeric portion 38 bears against the internal surface 32 of tube 12 under certain conditions of operation of the device herein, while internal surface 42 of portion 44 bears against the annular ring 46, as discussed above