SEMISUBMERSIBLE MULTI-STAGE PUMP UNIT Russian patent published in 2012 - IPC F04D13/08 F04D7/04 F04D29/41 

FIELD: engines and pumps.

SUBSTANCE: proposed unit comprises composite housing 1 with duct-type guide vanes 2 and cover 37 secured on composite string. Two-bearing rotor shaft 4 with impellers 3 and piston 12 of unloading device is coupled via shaft train with engine mounted on the plate. Proposed unit comprises two pairs of end seals 7-10 with separation chamber filed with gate fluid. Filter 38 is arranged at pump inlet. Chamber between piston 12 and double end seal 7, 8 communicates via control valve 19 with low-pressure area. Pumped fluid forced into unloading device is pre-cleaned by cyclone separator 16. Top section of housing 32 of lower bearing 6 has ledge 33 with narrow cutouts that feature width not exceeding 3 mm. Said lower bearing 6 represents an antifriction bearing separated from pumped fluid by double end seal 9, 10.

EFFECT: reliable log-term operation.

3 cl, 2 dwg