I claim the ornamental design for a cone for a centrifuge device, as shown and described.
FIG. 1 is a perspective view of a cone for a centrifuge device according to an embodiment of my new design.
FIG. 2 is a front view thereof, the rear view being identical to the front view.
FIG. 3 is a top view thereof; and,
FIG. 4 is a bottom view thereof.
The broken lines in FIGS. 1, 2 and 4 are included for the purpose of illustrating portions of the cone for a centrifuge device that form no part of the claimed design.