The impeller hubs are compressed against each other so that the axial load generated by the impellers is transmitted through their adjacent hubs to a two-piece ring at the bottom of the pump shaft. The axial thrust load of the stages and shaft are then transmitted through the shaft to the thrust bearing chamber (as seen in figure below).
The Thrust Chamber (TC) is an arrangement of radial and angular bearings. The TC is mounted on a rigid vertical support between the motor and the pump intake. It contains both bearings which absorb the down thrust load from the pump as well as radial bearings to support the weight of the shaft and couplings. The TC is a self-lubricating machine with its own supply of lubricating/cooling oil. The TC transmits the torque from the motor via a keyed coupling on the input side to the spline coupling on the pump side.