S/L Geometry: The helical eccentric screw/rotor has a circular cross section, a very long pitch and large thread depth. It oscillates in the fixed stator, which has an internal thread with the same profile as the rotor, but with 180° interval twin starts and twice the pitch.
As a result of this 1/2 ratio lobe geometry, cavities are formed between the rotor and the stator when the two are put together. When the rotor turns within the stator, the progressing cavities between the two transport the medium in a smooth and continuous manner from the suction to the discharge side of the stator.
The pressure capability depends on the number of stages, with the differential pressure being up to 6 bar per stage.
The 2-stage NEMO® Pump in S-Geometry can reach differential pressures of up to 12 bar at a flow rate of 100%. A single-stage NEMO® Pump in L-Geometry has the same outer dimensions as the 2-stage pump in S-Geometry, the same diameter and eccentricity, but twice the pitch of the rotor/stator. This pump therefore produces a flow rate of 200% over the S-Geometry at a differential pressure of up to 6 bar.
The S-Geometry: -
Compact dimensions even with a high number of stages
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Large cross sections of rotor inlet
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Low flow velocity/NPSH
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Conveyance of compacted products
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Conveyance of large suspended solids
The L-Geometry:
D/P Geometry:
The helical eccentric screw/rotor has an elliptical cross section, a long pitch and large thread depth. It turns in a circular eccentric motion within the fixed stator, which has an internal thread with the same profile as the rotor, but with 120° interval triple starts and 1.5 times the pitch. As a result of this 2/3 ratio lobe geometry, cavities are formed between the rotor and the stator when the two are put together. When the rotor turns within the stator, the progressing cavities between the two transport the medium in a smooth and continuous manner from the suction to the discharge side of the stator. The cavities in D/P-Geometries are about 75% of the size of those in S/L-Geometries, but they are passed through twice per revolution instead of only once, resulting in a flow rate 50% higher. The flow rate is determined by the pitch of the rotor/stator, the elliptical diameter and the eccentricity, as well as by the pumping rotation speed. The pressure capability depends on the number of stages, with the differential pressure being up to 6 bar per stage. The 2-stage NEMO® Pump in D-Geometry can reach differential pressures of up to 12 bar at a flow rate of 150% over that of the S-Geometry. A single-stage NEMO® Pump in P-Geometry has the same outer dimensions as a 2-stage pump in D-Geometry, the same ellipse and eccentricity, but twice the pitch of the rotor/stator. This pump therefore produces a flow rate of 300% over that of the S-Geometry at a differential pressure of up to 6 bar.
The D-Geometry:
The P-Geometry: -
Compact dimensions with very high flow rates
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Almost pulsation-free conveyance
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High dosing precision
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Good volumetric efficiency / long service life due to long seal line between rotor and stator
