Patent ID: 8707510

Claim:
An extraction cleaning apparatus adapted for movement across a surface to be cleaned comprising: a fluid delivery system including a fluid distributor and a fluid supply tank fluidly connected thereto, the fluid distributor being adapted to deliver cleaning fluid from the fluid supply tank to the surface to be cleaned; a fluid recovery system comprising: a suction nozzle having a suction nozzle inlet adapted to recover cleaning fluid and debris from the surface to be cleaned and a suction nozzle outlet opening; a recovery tank adapted to collect liquid and debris and having an inlet; a centrifugal separator comprising: a cylindrical housing defining a separation chamber and having: a separator inlet fluidly positioned at a lower portion of the cylindrical housing and connected to the suction nozzle outlet opening, the separator inlet comprising an inlet opening in the cylindrical housing and an inlet conduit that introduces the air and liquid into the separation chamber at a tangential angle to the separation chamber through the inlet opening, the inlet conduit having elongate sidewalls, a top wall, and a bottom wall defining a rectangular cross-section; a separator liquid outlet in a lower portion of the cylindrical housing, spaced from the separator inlet and in fluid communication with the recovery tank inlet, the separator liquid outlet comprising a rectangular liquid outlet opening in the cylindrical housing of substantially the same shape and size as the inlet opening, wherein the liquid outlet opening is substantially diametrically opposed to the inlet opening; an air outlet in a bottom portion of the separation chamber for exhausting air from the separation chamber; and an exhaust stand pipe within the separation chamber in fluid communication with the air outlet and extending upwardly therefrom to an open upper end to exhaust air separated from liquid in the separation chamber, wherein the open upper end is above the entire inlet opening and the entire liquid outlet opening; and a suction source in fluid communication with the suction nozzle and the cylindrical separator and adapted to draw air, soiled cleaning fluid and debris from the surface to be cleaned through the suction nozzle and pass the same into the separation chamber.