SCREW CENTRIFUGAL PUMP Russian patent published in 2008 - IPC F04D1/04 F04D29/06 F04D29/66 

FIELD: engines and pumps.

SUBSTANCE: screw centrifugal pump incorporates two-way inlet impeller 3 fitted on shaft 2 in casing 1. Screws 4, 5 have opposing screw blades 6 and cylindrical inlet section 7 changing into section 8 with the outer diameter smoothly decreasing towards the outlet. Screws 4 and 5 are fitted in profiled bushes 9. Plain bearings are arranged on both sides. Every bearing represents a sleeve fitted on shaft 2 and in the liner to form a hydrostatic space communicating, via a hydro cyclone, with the pump outlet. A drum-type discharge unit is arranged behind the bearings, while the end face seals are fitted on both shaft ends. Screw blade pitch of screws 4 and 5 smoothly decreases towards the outlet. Centrifugal impeller 3 represents two axioradial wheels on its both sides. The number of blades of the said wheel varies. The blade angle of screws 4 and 5 increases from the inlet to outlet. The invention features specific ranges of ratios between outer diameters of the screws outlet and inlet, screws grate density at the inlet and outlet and on the axioradial wheel inlet axial section, blade angles on the axioradial wheel and screws inlet axial sections and the number of axioradial wheel blades on its axial, diagonal and radial sections.

EFFECT: longer faultless operation.

2 cl, 11 dwg