US Patent 7306640 Vacuum cleaner

A vacuum cleaner includes a first dirt separation unit and a second dirt separation unit. The first dirt separation unit has a first inlet port through which a suction air stream including dirt particles is introduced thereinto, and the second dirt separation unit has a second inlet port through which the air stream introduced into the first dirt separation unit is introduced into the second dirt separation. The first and the second inlet port are disposed such that they are not registered with each other. Accordingly, the dirt particles suctioned are separated in two stages, thereby decreasing the possibility of occlusion of a filter and rapid deterioration of a suction force.