CENTRIFUGAL SCREW PUMP Russian patent published in 2012 - IPC F04D9/04 F04D13/04 

FIELD: engines and pumps.

SUBSTANCE: pump includes bodies 8, 26, 28, centrifugal impeller 2 with hub 3, which is installed on shaft 1, and screw 15. Shaft 1 is installed in bearing 7 protected with seal 40. Inside hub 3 on bearings 10, 11 there is installed intermediate shaft 9 so that a gap is formed. Inner shaft 12 having axial non-through hole 34 is formed inside intermediate shaft 9 on bearings 13, 14 so that a gap is formed. On the end of shaft 12, on the pump inlet side there installed is screw 15, and impeller 16 of hydraulic turbine 17, which is installed inside shaft 1, is fixed on opposite end. On shaft 9, on the inlet side between screw 15 and impeller 2 there installed is screw 19, and on the other end - impeller 20 of hydraulic turbine 21. Rear seal 31 under which discharge cavity 32 is made is provided on impeller 2. Shaft 1 is hollow and has front, middle and rear cavities 23, 24 and 25. Hydraulic turbine 17 is installed between cavities 24, 25 and hydraulic turbine 21 is installed between cavities 24, 23. Inner thrust bearing 14 is installed inside nozzle assembly 22 of hydraulic turbine 21. Cavity 32 is connected through hole 42 made in shaft 1 to cavity 25. In hub 3 there made are through holes 33 connecting cavity 23 to cavity 6 of impeller 2.

EFFECT: improving cavitation properties of pump and providing unloading of axial forces of inner and intermediate shafts.

3 cl, 2 dwg