Operating steam of the screw pump is consisting of metal rotor (single-wound external helix) and rubber stator stator (double-wound inner helix), herewith, the hermetically secluded holes are created on the line of enclosure between stator and rotor, that under the rotation of the rotor moves to side of the discharge. The quantity of operating (screw) steam runs is defined by potential pressure, which can be reached by screw pump, and the volume of secluded holes and rotation speed is define by its capacity.
By this way, crew pump is self-priming pump of comprehensive type and allows the regulation of capacity in the wide range with nominal pressure loss. These peculiarities of screw pump allow to work with viscous medium, liquids with sediments, multiphase medium with gas constituent, etc.