US Patent 7828530 Electric motor pump for swimming pool maintenance

The invention concerns a dual pump, comprising an electric motor (18) including a drive shaft, the shaft including, at each of its axial ends, a shaft output (21, 22), and two pump impellers, each shaft output driving a respective pump impeller, one first of the pump impellers (23) operating at low pressure and high flow rate, and the second of the pump impellers (30) operating at higher pressure and lower flow rate. The water pumped by the second pump impeller (30) is drawn proximate the outlet of the first pump impeller (23) and returns to the inlet of the second pump impeller. The drawing point is situated in a low pressure pump chamber, upstream of the low pressure outlet (16). The invention is applicable to swimming pool maintenance.