CENTRIFUGAL SCREW PUMP Russian patent published in 2007 - IPC F04D1/04 F04D9/04 

FIELD: mechanical engineering; centrifugal screw pumps.

SUBSTANCE: invention can be used ion fire fighting. Proposed centrifugal screw pump contains housing 1 with suction branch pipe 2 and rotor secured on shaft 3 arranged in housing and including closed-type centrifugal impeller 4 and screw with blades 5 made on bushing 6. Inlet and outlet sections of screw are arranged coaxially in suction branch pipe 2 and inside neck 7 of impeller 4. Screw is of double start type. Its blades 5 are installed square to bushing 6 and are limited in cross section from working and rear sides by identical broken lines. Each said line smoothly conjugates with outline of bushing 6, being made concave in radius and, on periphery, in form of section of straight line tilted to axis of pump rotation at acute angle Diameter of blades 5 of screw is reducing towards impeller 4.

EFFECT: improved anticavitation characteristics, reduced cavitation erosion of pump rotor, improved reliability, delivery and increased service life of pump.

4 cl, 1 dwg