F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
F04D—NON-POSITIVE-DISPLACEMENT PUMPS
F04D17/00—Radial-flow pumps, e.g. centrifugal pumps; Helico-centrifugal pumps
F04D17/02—Radial-flow pumps, e.g. centrifugal pumps; Helico-centrifugal pumps having non-centrifugal stages, e.g. centripetal
F04D17/025—Radial-flow pumps, e.g. centrifugal pumps; Helico-centrifugal pumps having non-centrifugal stages, e.g. centripetal comprising axial flow and radial flow stages