US Patent 7343641 Dirt collection assembly with volcanic airflow

A vacuum cleaner is provided including a housing, a nozzle inlet, a suction generator carried on the housing and a dirt cup carried on the housing. The dirt cup includes a bottom wall, a sidewall, a dirt collection chamber, an air inlet to the dirt collection chamber in the bottom wall and an air outlet from the dirt collection chamber. A method of directing an airstream in a dirt cup is also provided. That method includes directing the airstream upwardly through the dirt cup in an air inlet conduit, discharging the airstream from the air inlet conduit into the dirt cup in a substantially hemihorn torus shape and exhausting the airstream from the dirt cup.