Screw pump lifting mechanism is different from of centrifugal and axial flow pump, its speed is very slow, generally only 20-90r/min. It has the advantage of not having to set up collection wells and closed pipeline, pump facilities simple, at the same time, because of its low speed, the pumping of sewage, slow increase of activated sludge floc, less damage. Its main disadvantage is the head is low, generally not more than 6-8m, the pump must be inclined installation, larger area.
Screw pump is a spiral blade on the rotation to achieve the purpose of water. Screw pump inclined placed in water, the inclination angle on the surface is less than the helical blade spiral shaft, when the motor through the transmission device drives the screw shaft is rotated, the helical blade is in contact with the water, the water from the helical blade to blade P, water under the action of gravity, with the leaf fell to Q, the inertia force due to rotation when the water leaves, Q to P, then under the action of gravity, water and comes down to the leaf level bottom, so continuous cycle, water along the helical axis is a level to mention, the most high end to screw pump and flow