The ornamental design for a portablefan, as shown and described.
FIG. 1 is a front perspective view of a portable fan showing my new design;
FIG. 2 is a rear perspective view thereof with the support member shown in
an alternation position;
FIG. 3 is a side elevation thereof;
FIG. 4 is a fragmentary bottom perspective thereof with the support
omitted; and
FIG. 5 is a front perspective view of a modified form of the portable fan
shown in FIG. 1, wherein the modification resides in the omission of the
front support bracket.