CENTRIFUGAL PUMP Russian patent published in 2010 - IPC F04D9/04 F04D13/04 

FIELD: engines and pumps.

SUBSTANCE: pump includes inlet and outlet housings 16, 18, impeller 2 with hub 3, which is installed on shaft 1, and screw 10. Inside hub 3 there installed are intermediate and inner shafts 6, 8. On one end of inner shaft 8 there installed is the first screw 10 with rotor wheel 11 of the first hydraulic turbine on the periphery. On ends of intermediate shaft 6 there installed is the second screw 12 and impeller 13 of the second hydraulic turbine. Nozzle device 14 of hydraulic turbine is installed in cavity of hub 3. In hub 3 there are through holes 24 connecting the cavity of impeller 2 to cavity 25 in hub 3. After rotor wheel 13 of hydraulic turbine there is a bypass channel for return of pumped product to cavity between screws 10, 12. Bypass channel is made in the form of blind axial hole 27 in inner shaft 8 and radial holes 28 arranged between screws 10, 12 and opening inside hole 27. Inlet and outlet housings 16, 18 are connected by means of bypass channel 29 for drive of the first hydraulic turbine. Screws 10, 11 are made so that they can rotate in opposite directions.

EFFECT: improving cavitation properties of pump.

3 cl, 2 dwg