| CPC A47L 11/4055 (2013.01) [A47L 9/009 (2013.01); A47L 9/0411 (2013.01); A47L 9/0444 (2013.01); A47L 9/0455 (2013.01); A47L 9/0477 (2013.01); A47L 9/0494 (2013.01); A47L 11/302 (2013.01); A47L 11/4011 (2013.01); A47L 11/4038 (2013.01); A47L 11/4041 (2013.01); A47L 11/4069 (2013.01); A47L 11/4075 (2013.01); A47L 11/4088 (2013.01); A47L 11/125 (2013.01); A47L 11/145 (2013.01); A47L 11/185 (2013.01); A47L 11/201 (2013.01)] | 19 Claims |

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1. A surface cleaner comprising:
a base configured for movement across a surface to be cleaned, the base including a base housing; and
a fluid-dispensing system operable for delivering fluid to the surface to be cleaned, the fluid-dispensing system including a centrifugal pump mounted in the base housing, the centrifugal pump including:
a casing having an inlet through which fluid is drawn, an outlet through which fluid is discharged, a volute scroll in fluid communication with the inlet, an expansion chamber in communication with the outlet, a throat fluidly connecting the volute scroll with the expansion chamber, and a weep hole fluidly connecting the expansion chamber with the volute scroll; and
an impeller configured to rotate in the volute scroll to pump fluid from the inlet to the outlet through the throat and the expansion chamber, with fluid in the expansion chamber separating from air in the expansion chamber and returning to the volute scroll through the weep hole, thereby priming the centrifugal pump.
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