Patent ID: 6045326
Filing Date: 2000-04-04
Classification: F04D

Abstract:
A pump having combined centrifugal and anal flow for pumping a liquid, comprising:a pump housing provided with at least one flange portion;a rotatable centrifugal impeller having spiral vanes for centrifugal pumping and an eye region at an impeller inlet of the rotatable centrifugal impeller,an electric motor including a rotor; anda cylindrical axial flow tube attached to the rotatable centrifugal impeller at the impeller inlet said axial flow tube having an internal Archimedes' spiral vane having a free diameter in a center thereof the internal spiral provided with a helical surface having a constant angle director cone;wherein the cylindrical axial flow tube extends the eye region of the centrifugal impeller to the flange portion of the pump housing, and the internal Archimedes' spiral vane imparting a pre-whirl to the liquid and increasing pressure at the eye region to reduce cavitation by forcing flow of the liquid to the pump impeller, said cylindrical axial flow tube and said rotatable centrifugal impeller together pumping the liquid,wherein said internal Archimnedes' spiral vane completes at least 1 full rotation about an internal diameter of said axial flow tube along the length of said axial flow tube,the cylindrical axial flow tube further being connected to the motor rotor as a shaft for the electric motor and the pumped liquid directly cooling the electric motor.