The ornamental design for a centrifuge, as shown and described.
FIG. 1 is an isometric view of our new centrifuge design;
FIG. 2 is a front view of the centrifuge shown in FIG. 1;
FIG. 3 is a cross-sectional view taken along line 3-3 of FIG. 2.
FIG. 4 is a right side view of the centrifuge shown in FIG. 1;
FIG. 5 is a rear view of the centrifuge shown in FIG. 1;
FIG. 6 is a left side view of the centrifuge shown in FIG. 1;
FIG. 7 is a top view of the centrifuge shown in FIG. 1; and,
FIG. 8 is a bottom view of the centrifuge shown in FIG. 1.
The even dash lines in FIG. 3 represent an unclaimed portion of the centrifuge and the dash-dot lines in the drawing views represent environments. None of the broken lines form a part of the claimed design.