Pressure balanced fuel pump impeller

Abstract

An electric motor turbine-type fuel pump has an impeller driven to rotate by the motor and received between opposed faces of a first body and a second body defining a pumping channel about the periphery of the impeller, each face has a plurality of circumferentially spaced and separate cavities disposed radially inwardly of the pumping channel and constructed to contain pressurized fuel adjacent the impeller to balance the axial forces across the impeller and center the impeller between the first body and second body. If desired, to ensure communication between a cavity and the pumping channel, a shallow groove or flow passage can be provided extending between the cavity and the pumping channel. The cavities in both the first body and second body are complementarily sized and arranged to provide a surface area adjacent the impeller and a pressure therein sufficient to balance the forces acting on each side of the impeller. With the impeller centered between the first body and the second body, a slight gap is provided between the impeller and each body and fuel leakage between the impeller and each body provides a fluid film or fluid bearing which reduces the resistance to rotation of the impeller. This reduces the wear of the impeller in use and the torque needed to rotate it and increases both the efficiency and the life of the fuel pump in use.

Dependencies are inferred from the claim text.