CENTRIFUGAL SCREW PUMP Russian patent published in 2011 - IPC F04D9/04 F04D13/02 

FIELD: engines and pumps.

SUBSTANCE: invention relates to pump building industry. Centrifugal screw pump includes housings 5, 21, 23, centrifugal impeller 2 with hub 3, which is installed on shaft 1 which is mounted on bearing 4 protected with seal, 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 which is fixed on shaft 8 by means of front conical nut 11. On opposite end of shaft 8 there fixed is impeller 12 of hydraulic turbine 13. On one end of shaft 6 there installed is the second screw 15 between impeller 2 and screw 10. In hub 3 cavity there installed is reduction gear 17 connecting shafts 6, 8. In hub 3 there are holes 28 connecting impeller 2 cavity to cavity 18 in hub 3. On rear edge of impeller 2 there made is rear seal 26 under which there made is unloading cavity 27. Shaft 1 is hollow and radial holes 35 led out to cavity 27 are made in it. Screws 10, 15 have the possibility of being rotated in opposite sides.

EFFECT: invention is aimed at improving cavitation properties of pump.

2 cl, 2 dwg