Geometrical Models

The right geometry for every application – it’s possible with the NETZSCH modular design!

The NEMO® Pump belongs to the family of rotary positive-displacement pumps. The two conveying elements are comprised of the rotor which turns within a fixed stator.
The design is modular; the outer dimensions of the pumps are identical, as are the connections on the suction side and the discharge side, for all four geometries. With the exception of the rotor and the stator, all other components are also identical. This allows you to adapt a NEMO PUMP® to new flow rates or pressures after installation, by simply exchanging the rotor and stator to better suit the new conditions.

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 having 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. As the rotor turns within the stator, the progressing cavities between the two transport the substance in a smooth and continuous manner from the suction to the discharge side of the stator.
The flow rate is determined by the pitch of the rotor/stator, the diameter, the eccentricity, and by the pumping rotation speed. The pressure capability depends on the number of stages, with the differential pressure being up to 90 psi / 6 bar per stage.
The 2-stage NEMO® Pump with S-Geometry can reach differential pressures of up to 180 psi / 12 bar at a flow rate of 100%. A single-stage NEMO® Pump with L-Geometry has the same outer dimensions as the 2-stage pump with 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 90 psi / 6 bar.

S Geometry

  • very gentle conveyance
  • compact dimensions even with a high number of stages
  • large cross sections of rotor inlet
  • low flow velocity/NPSH
  • conveyance of compacted products
  • conveyance of large suspended solids

L Geometry

  • good volumetric efficiency
  • long service life due to long seal line between rotor and stator
  • compact dimensions with high flow rates.

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, that 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. As 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 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 90 psi /6 bar per stage. The 2-stage NEMO® Pump in D-Geometry can reach differential pressures of up to 180 psi / 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 90 psi / 6 bar.

D Geometry

  • very compact dimensions
  • at high pressures and flow rates almost pulsation-free conveyance
  • high metering precision
  • good volumetric efficiency
  • long service life due to long seal line between rotor and stator

P Geometry

  • compact dimensions with very high flow rates
  • almost pulsation-free conveyance
  • high metering precision
  • good volumetric efficiency
  • long service life due to long seal line between rotor and stator