Patent ID: 7686572

Claim:
A pump for the drawing-in of a fluid, comprising at least one centrifugal wheel having a fluid inlet edge and a fluid outlet edge, the centrifugal wheel being driven in rotation by a shaft mounted so as to be able to rotate relative to a housing of the pump, the pump further comprising an axial balancing system comprising a high-pressure flow space defined between the housing and an upstream face of the centrifugal wheel, a low-pressure flow space defined between the housing and a downstream face of the centrifugal wheel, the high-pressure flow space comprising an inlet arranged in proximity to the outlet edge of the centrifugal wheel and an outlet arranged in proximity to the inlet edge of the centrifugal wheel, said outlet of the high-pressure flow space being equipped with first flow restriction means, the low-pressure flow space comprising an inlet arranged in proximity to the outlet edge of the centrifugal wheel, said inlet of the low-pressure flow space being equipped with second flow restriction means, the low-pressure flow space further comprising an outlet having an annular passage forming an axially variable flow restriction and opening radially onto an annular discharge space defined around said shaft radially internally relative to the annular passage, the annular space communicating with a region in which the pressure is lower than that in the low-pressure flow space, wherein the axial balancing system further comprises a plurality of vanes formed on the housing, said vanes extending radially and in a centripetal direction immediately adjacent the outlet edge of the centrifugal wheel.