Patent ID: 7789617

Claim:
A pump for liquefied gas comprising: a suction stage having at least one centrifugal wheel, the suction stage comprising: a rotational impeller equipped with a hub having a downstream surface extending axially toward the centrifugal wheel, the hub being arranged upstream of the centrifugal wheel, and a diffuser comprising a plurality of blades surrounding the downstream surface, wherein the hub further has a median portion and axial ends, the hub having a greater diameter in its median portion than at its axial ends so that the downstream surface converges toward the centrifugal wheel, wherein the blades of the diffuser have free ends, said blades protruding radially toward said downstream surface of the hub, and wherein the downstream surface and an outer shell of the diffuser radially define an annular duct which allows a drawn-in fluid to pass, the annular duct having a substantially constant radial height over the axial length of the downstream surface.