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

FIELD: engines and pumps.

SUBSTANCE: invention relates to pump building industry. Pump includes housings 8, 24, 26, centrifugal impeller 2 with hub 3, which is installed on shaft 1 in bearing 7 protected with seal 49, and screw 15. Inside hub 3 on bearings 10, 11 installed so that cavity 31 is formed between them there installed is intermediate shaft 9. Inside shaft 9 on bearings 13, 14 there installed is inner shaft 12 on opposite ends of which there installed is screw 15 and impeller 16 of hydraulic turbine 17, which is installed inside shaft 1. On opposite ends of shaft 9 there installed is impeller 20 of hydraulic turbine 21 and screw 19 is installed between screw 15 and impeller 2. In hub 3 there are holes 32 attaching cavity 31 between bearings 10, 11 to cavity 6 of impeller 2. In holes 32 there installed are centrifugal flow controls 33. On edge of impeller 2 there made is seal 28 under which there made is unloading cavity 29. Shaft 1 is hollow and it includes cavities 23, 41, 42. Between cavities 41, 42 there installed is hydraulic turbine 17, and hydraulic turbine 21 is installed between cavities 41 and 23. Bearing 14 is installed inside nozzle unit 22 of hydraulic turbine 21. In shaft 1 between bearing 7 and seal 49 there made are radial holes 50 led out to cavity 42.

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

2 cl, 5 dwg