PUMP

摘要

The pump of the present invention has a housing which accommodates an axial impeller set on the pump drive shaft. The impeller has a hub which carries a number of the helical impeller blades held in position thereto and defining a plurality of blade channels for the liquid being handled to pass. An additional intake axial impeller with the helical impeller blades is set on the pump drive shaft before the axial impeller as viewed in the direction of liquid flow, said additional intake axial impeller having its outside diameter smaller than the outside diameter of the axial impeller, and the lead of helix of the impeller blades thereof is lower than the lead of helix of the impeller blades of the axial impeller at the entry thereof, while the ratio between the outside diameter of the additional intake axial impeller and the outside diameter of the axial impeller, and the ratio between the lead of helix of the impeller blades of the additional intake axial impeller and the lead of helix of the impeller blades of the axial impeller across the outside diameter of both respective impellers are selected so as to provide for high pump suction capacity.