Patent ID: 8161597

Claim:
A shop vacuum cleaner having multiple successive dust collection stages, comprising; a primary dust collection barrel having a side wall and a base defining an interior, and having a generally circular upper rim; a lid member adapted to fit onto the upper rim of said primary dust collection barrel, including a generally flat plate member having a peripheral edge and an annular flange fitting onto said upper rim; a cyclonic separator mounted directly atop said lid member on said flat plate thereof within said peripheral edge, including an air inlet port for receiving a flexible intake hose, a conic chamber receiving said airflow from said air inlet port, with a nose end at a bottom thereof; a dust outlet at said nose end communicating through an opening in said lid member with the interior of said primary dust collection barrel; and a vortex tube at an upper end and extending from within a cyclonic chamber thereof, the vortex tube serving as an air outlet; a secondary dust collection drum mounted atop the flat plate member of said lid member within the circumferential edge thereof and alongside the cyclonic separator, and having a generally circular upper rim, the drum including an inlet duct penetrating said side wall of said drum; a secondary conduit connecting the air outlet of said cyclonic separator with the inlet duct of said secondary dust collection drum, such that air flows from said air outlet into the inlet duct of said secondary dust collection drum; a pre-filter dust collection bag mounted on said inlet duct inside said secondary dust collection drum; a vacuum head having a housing with a lower face fitting onto the upper rim of said secondary dust collection drum, including a vacuum blower and a vacuum intake duct positioned at said lower face for drawing air from an interior of said secondary dust collection drum; a final filter cartridge positioned over the vacuum intake duct of said vacuum head within said drum; and means securing the final filter cartridge sealable against the lower face of said vacuum head; such that in operation an air stream containing entrained dust passes from said flexible intake hose into said cyclonic separator, where dust is separated out and drops into the primary dust collection barrel, the air stream continues out of said air outlet and then through the secondary conduit and then through the pre-filter bag within the secondary dust collection drum, and then through the final filter cartridge and the intake duct of the vacuum head, such that the vacuum head exhausts clean, filtered air into the ambient.