The ornamental design for a filterassembly for an air purifier, as shown and described.
FIG. 1 is a top, front, right side perspective view of a filter assembly for an air purifier of the new design removed from an environment of use for clarity of disclosure.
FIG. 2 is a top, rear, right side perspective view thereof.
FIG. 3 is a front elevation view thereof.
FIG. 4 is a rear elevation view thereof.
FIG. 5 is a left side elevation view thereof, the right side elevation view being a mirror image.
FIG. 6 is a top plan view thereof.
FIG. 7 is a bottom plan view thereof.
FIG. 8 is a top, front, right side perspective view thereof, shown in an environment of use; and,
FIG. 9 is a rear elevation view, thereof.
The broken lines shown in FIGS. 1 and 3 are for purposes of illustrating portions of the filter assembly for an air purifier that forms no part of the claim. The broken lines shown in FIGS. 8 and 9 are for the purposes of illustrating and environment that forms no part of the claim.