Cavity pumps for Biogas & Industry

Cavity pumps – Type N and NF

The ARMATEC cavity pumps are used since several years in all sectors of industry.

For Biogas plants and Industy we offer two types of Standard Cavity pumps:

Type N
Foot-mounting gearmotor and mounted on a baseframe

  • N 140
  • N 120

The eccentric screw pumps from N series are high quality and very robust pumps, which are characterized by the following features:

  • Large sized suction housing
  • Up to 5 suction ports possible
  • Generously dimensioned storage chair
  • Drive shaft with coupling
  • Use of a foot motor for easy installation
  • Construction on a stable base frame

Type NF
Flange-mounting gearmotors

  • NF 80
  • NF 100


The NF eccentric screw pump is a compact and cost cavity pump that is easy to install and does not require a separate base frame. With flow rates of up to 30 m³ / h, this series is a good alternative to the N series. In this series, the geared motor is bolted directly to the eccentric screw pump via a flange

Exzenterschneckenpumpe NF


  • 3 – 24 bar
  • 4 – 360 m³/h
  • Rotor: hollow or full rotors in steel / stainless steel (ss304/ss316) and hardened  – depending on the application
  • Different joints
  • Oil-chamber housing with mechanical seals
  • Stators in different elastomers (NBR, EPDM, PTFE, PU, CSM) – also available in adjustable versions for a longer service life
  • Installation and maintenance without special tools
Exzenterschneckenpumpe NF

Conveying of viscous materials:

  • raw materials which are reproductive like corn, grass
  • substrates for Biogas production, food residues, vegetable waste
  • liquid manure
  • waste water
  • emulsion
  • sludge, slurry
  • cut up fruits
  • colours and lacquers …
Aufbau Exzenterschneckenpumpe NF

Restressable Stator:

  • 1 – 4 steps available



Stator für Exzenterschneckenpumpe

Dry running protection

The resistance thermometer PT 100 is used for direct temperature measurement in the stator. The thermometer includes an evaluation unit with connection cable.

Pressure gauge

As another accessory is our pressure gauge with switching contact for pressure monitoring.

Pump selection

Using the diagram, you can make the preselection of the Armatec-FTS progressing eccentric screw pumps

  1. Selection flow rate m³ / h
  2. Selection revolutions / min
  3. From the intersection point along characteristic curve selection pump size results in a pump N 80 for example



NF 80 + 100 / N 120 + 140


Chemical Industry: acids, bases, tensids, solvents, colors, emulsions, slurry, molasses etc.
Biogas plants: manure from cows, pigs, grass and maize silage
Agriculture: cow and pig manure
Waste water treatment plants: waste water, sewage sludge etc.

Dry matter content up to 15 %
Substrate temperature up to 45°C
pH value 6.5 – 8.5
Dynamic viscosity: owable
Partical sizes. depending on rotor/stator sizes (16-30mm)


Effciency class: IE 2 < 7.5 kW |I IE3 > 7,5 kW Suitable for frequency converter
Type: ange-mounting (B5) or foot-mounting (B3) Flange-mounting motor for < 7.5 kW and foot-mounting > 7.5 kW
Frequency: 50 Hz I 60 Hz
Voltage: 400 V I 460 V
Protection class: IP 55
Motor rotation speed: 1,500 rpm
Motor protection with 3 PTC thermistor


Type NF: horizontally on feeds – anged motor
Type N: mounted on a base frame – foot-mounting motor

Type TP: submersible NF pump up to 4m tank depth


Hollow rotor, steel, single-stage
All rotors are hardened for a longer lifetime

Armatec FTS own design – compatible and suitable to our stators


Flow rates: 5 – 120 m3/h with frequency converter Housing: galvanized steel with cleaning opening
Cardan shaft
Sealing: oil chamber with mechanical seals (on request with gland packing)
Suction and pressure nozzle: PN 16 I DN 125 – 200


Material: SBR (NBR, EPDM, VITON etc.)
Single-stage (multible stages on request)
Adjustable for a longer lifetime
With 1⁄2” threaded sleeve for resistance thermometer for dry-running protection


Dry running protection, consisting of:
resistance thermometer, connecting cable, evaluation device

Pressure gauge, additional suction nozzles, joint shaft with screw conveyer


Direct control, soft-starter or frequency converter Supplied without connecting cable

Adapted frequency converter, permitting optimum performance – on request (4 – 22 kW)
Motor with separate fan: frequency < 20 Hz

Following you will find examples of the eccentric cavity pumps operantional.

Questions? Request for Proposal?

Our employees will answer your questions

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