CENTRIFUGAL SCREW PUMP Russian patent published in 2011 - IPC F04D9/04 F04D13/04 

FIELD: engines and pumps.

SUBSTANCE: pump includes housings 8, 24, 26, 51, centrifugal impeller 2 with hub 3 having inner cavity 6; impeller is installed on shaft 1 in bearing 7 protected with seal 52. Intermediate shaft 9 is installed inside hub 3 on bearings 10, 11. Inner shaft 12 is installed inside it on bearings 13, 14. Screw 15 is installed on the end of shaft 12 on the pump inlet side, and impeller 18 of hydraulic turbine 17 is fixed on opposite end of shaft 12. On shaft 9 on the inlet side between screw 15 and impeller 2 there installed is screw 19, and on its other end there installed is impeller 20 of hydraulic turbine 21. In hub 3 there are two groups of holes 32, 33 of various diametres to connect cavity 6 of impeller 2 to inner cavity 23 and cavity 31 between bearings 10, 11 to cavity 6 of impeller 2. In holes 33 there installed are centrifugal flow controls 34. On rear end face of impeller 2 there is seal 29 under which there is discharging cavity 30. Shafts 1 and 12 are of hollow type. Hydraulic turbines 17, 21 are installed in shaft 1. Bearing 14 is installed inside ring 46 on ribs 47. Holes 42, 43 entering cavity 31 are made in middle part of shafts 12, 9.

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

2 cl, 5 dwg