MAIN CIRCULATING PUMP UNIT Russian patent published in 2017 - IPC F04D13/06 F04D29/47 F04D29/58 G21D1/04 G21C15/243 

FIELD: engines and pumps.

SUBSTANCE: invention relates to nondisplacement pumps and can be used at NPP in reactor coolant pumps of primary circuit of nuclear power unit. The pump unit comprises a vertical pump with bottom position of an impeller, a bottom radial journal bearing installed on the pump shaft above the impeller and lubricated by pumped fluid, an end shaft seal (24) located above the bottom radial bearing, and a radial-axial bearing installed in top chamber of the motor. Collar (15) of the radial-axial bearing is installed on shaft by cone fit and secured at its top end using bolts (16) and pressing flange (17). The radial-axial bearing is cooled with water from NPP system via screw pump installed on top end of the collar (15). The pump has stator and rotor inserts (21, 20) with screw thread. Water is delivered from top chamber (10) of the motor to its bottom chamber via pipeline installed on the motor wall, lubricates the radial bearing of the motor, the stator insert is made out of antifriction material, and is drained to NPP system via drainage pipeline. The chamber (10) is made in form of stainless steel housing (12) with installed stator elements of the radial-axial bearing. The housing (12) is covered by easy detachable tank (13). The bottom chamber is made in form of a stainless steel cylinder.

EFFECT: invention reduces load on the axial bearing, increases reliability and reduces time for repair and replacement of the axial bearing without motor dismounting.

3 dwg