US Patent 7740675 Cyclonic vacuum cleaner

A surface cleaning apparatus comprises a dirt inlet, a handle, a cyclonic cleaning unit comprising a plurality of cyclones and at least one dirt collection chamber, each of the plurality of cyclones having an outer wall, an interior, a fluid inlet downstream from the dirt inlet and a fluid outlet, the at least one dirt collection chamber having an outer wall and an interior, wherein the surface cleaning apparatus is constructed such that the interior of the at least one dirt collection chamber is visible from a position exterior to the surface cleaning apparatus and a fluid flow motor. The surface cleaning apparatus may have a filter with a housing that is at least partially transparent.