Abstract: A fluid-locked shaft seal comprises a housing with a shaft rotating therein having a seal ring affixed thereto for rotation therewith. A packing ring is disposed in the housing around the shaft and is fixed radially in respect to the shaft but is held by flexible means which permits its axial movement to some extent. A slide ring in the housing around the shaft is located between the seal ring and the packing ring and connected to the shaft for rotation that is substantially half the speed of rotation of the shaft. A pump rotor is formed with the seal and disposed on the side of the seal ring which is adjacent to the slide ring and generates a fluid flow in a deflecting channel which is defined in the housing by slide ring and the seal ring. A plurality of stationary impellers are disposed in the deflection channel and the slide ring has a turbine portion disposed in this channel.