Abstract: A centrifuge (10) for spinning blood sample tubes (14) has a conical rotor head (17) rotated within a cavity defined by an upwardly open annular trough (39) and a domed lid (50). The tubes (14) are inserted into transparent plastic tube holders (48). The holder top ends (60) are funnel-shaped to capture spillage and enable manual gripping. The trough has oppositely sloping walls (40, 41) and holder bottom ends (59) are exposed for ready viewing below the head bottom edge. A reader station (15) includes a pointer (80) with a lens (86) that has hairlines (87) for aligning the pointer over the spin tube (14a) to enter data on the red cell/plasma interface. The lines (87) are spaced to match the diagonal appearance of the interface. An interlock assembly includes a solenoid operated shuttle arm (108) that blocks movement of a pin (95) out of a bore (94) in a lid tab (92), unless motor (23) is deenergized.

Abstract: A centrifuge rotor head has a hollow frusto-conical housing with parallel inner and outer, upwardly and inwardly inclined walls joined at top and base ends by top and bottom annular flanges, and closed at the top by a central horizontally extending disc portion. The top flange is interrupted at equiangularly spaced intervals by circular openings which, together with an internal annular chamber, present steep angled cavities making angles of about 20.degree. with the rotor cone axis. The housing is capped at its upper end by a circumferentially-extending crown-shaped ring which has a plurality of upwardly and inwardly inclined projections located radially outward of the openings. The projections support the exposed upper ends of tubes placed in the cavities, to guard against neck breakage and stopper dislodgement during spinning.