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RingExtruder RE® for shear-sensitive continuous compounding of rubber, degassing of post-consumer PET-bottles in PET bottle to bottle Recycling and the challenging mixing of adhesives.

About multi-screw extruders

It is common knowledge that the advantages of multi screw extruders lie in the intermeshing section – the apex.  The apex is the base for the advantageous features of multi-screw extruders:

  • Dispersive mixing via elongational flow
  • Distributive mixing via stream divisions
  • Surface renewal for degassing
  • Self-cleaning for fast change-over times

Hence it is quite obvious that increasing the amount of screws in the extruder is an excellent way to boost the capability of the extruder. The RingExtruder RE® with 12 screw shafts is a co-rotating multi-screw extruder which was developed for challenging mixing and degassing applications.

Basic design and technological features

12 Screw shafts arranged symmetrically in a ring rotate in the same direction each on its own axis. The outer barrel and the stationary core enclose the screws with a narrow gap. Transportation of material takes place in a double helix: around the stationary core and around each screw. The intermeshing section between the screws, often also referred as the "apex", is used extensively in the RingExtruder RE® as the central point of the process technology. In the intermeshing section, material is passed to the adjacent screw with a change in flow direction and resulting in a 3D elongation flow without partial overloading and leads to an excellent dispersion, wetting and homogenization.

In addition, the RE provides a high surface-to-volume ratio which is unmatched by any other multi-screw extruder. The combination of the more frequent passage of the intermeshing section and the high surface-to-volume ratio is enhancing the degassing capability of the machine.

Finally the arrangement of the screw shafts in a ring largely compensates the spreading forces known in multi-screw extruders and therefore reduces barrel and screw wear.

The advantages

The optimized design creates competitive advantages in the production of shear sensitive compounds, challenging mixing and degassing applications.

Your Benefit

  • Superior dispersive and distributive mixing
  • Excellent degassing
  • Extraordinary temperature and residence time control
  • Reduced energy input and lower operating costs

Machine design and engineering

The RingExtruder RE® consists of the electrical drive, safety coupling, reduction and distribution gearbox as well as the processing unit. Barrels, screws and the core are divided into individual segments with modular configuration.

Solids or liquids can be added downstream on combi barrels using sidefeeders. Special barrels with large openings are available for degassing; alternatively degassing units can be used. In general the barrels are heated electrically and cooled with water. However in case of special requirements liquid temperature control systems can be applied as well.

On request we supply turnkey systems to our customer rather than just the RingExtruder RE®. The control concept allows to control and monitor the entire extrusion process.


The RingExtruder RE® has proven his advantages in various applications:

  • Continuous compounding of rubber for High Performance and Green Tires
  • PET-Recycling
  • Adhesives
  • Linoleum mixing
  • Pharmaceutical compounding