US Patent 7293324 Vacuum cleaner with level control

A vacuum cleaner has a housing that includes a separation chamber and collection chamber, a floor unit with a suction opening, and a passage between the suction opening and separation chamber. A suction source establishes a stream of air from the suction opening to the separation chamber for separation of liquids and contaminants. A controller stops the suction source when a level of liquid in the collection chamber rises to a predetermined level. There is a protective structure to shield at least a portion of the controller from circular movement of the liquid in the collection chamber. A structure in the separation chamber defines a path for the stream of air along an internal perimeter of the separation chamber.