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What started in 1983 with a vision of a new technical concept and with Detlef Gneuss´ entrepreneurial ambition and his wife, Christel Gneuss´ energetic support, the company has grown to an internationally active company, with innovations which have set world standards for the processing of polymer melts.

The goal from the start was to become the international market leader in polymer melt filtration and a top specialist in high quality, specialised pressure and temperature sensors. The original target markets were extrusion of profiles, pipes, sheets, and compound manufacturing. Because they were able to give previously unattainable solutions for processing problems thanks to wholly new technical approaches, Gneuss technical concepts and products began to establish themselves successfully in the market. Definitions like "constant melt filtration" and "pressure and process-constant" became yardsticks against which the competition's products had to be measured.

In the area of pressure and temperature sensors, Gneuss was the first company in the world to introduce a mercury-free melt pressure transducer and a melt temperature sensor with a ceramically-insulated tip.

Main Products


The unique MRS Extrusion System opens up entirely new avenues for the efficient degassing and extrusion of polymer melts. Furthermore, this system has outstanding dispersion performance for the introduction of gases and/or various types of additives. The MRS extruder is based on the traditional single screw extruder, but it has a multiple screw portion for maximum devolatilisation. The polymer melt is transferred to a huge single screw drum. The drum has eight tiny extruder barrels that run parallel to the main screw axis. The "satellite" screws are installed in these miniature extruder barrels and are powered by a ring gear in the main barrel. While rotating around the screw axis, the satellite screws rotate in the opposite direction as the main screw.

The "satellite" screws are installed in these miniature extruder barrels and are powered by a ring gear in the main barrel. While rotating around the screw axis, the satellite screws rotate in the opposite direction as the main screw. This raises the surface exchange of the polymer melt significantly. To allow the volatiles to escape freely, the MRS extruder has a huge venting hole (exposing the entire length of the satellite screws) that is totally under vacuum. This allows for unhindered access to the polymer melt, the surface of which is constantly and rapidly replaced by the action of the satellite screws in the multiple screw portion. Further, precise control of the melt temperature is possible as the temperatures of all the surfaces in contact with the melt can be controlled accurately.


The vacuum system plays a key role in the devolatilization process. Not only is it important to create a vacuum — the separation of solid particles from the volatiles which are extracted from the melt presents a particular challenge. Many extruders require an absolute pressure of < 5 mbar, using dry vane vacuum pumps. During the devolatilization of polymers, it is inevitable that monomers, oligomers and other solid particles or sublimates are sucked out. If these enter the pump, they will drastically reduce its operating life and for this reason, separating systems are needed which under tough industrial operating conditions are extremely maintenance intensive.

Thanks to its extremely high surface area exchange rate, the MRS extruder can in most cases provide excellent devolatilization with a vacuum of only 30 mbar. This permits the use of much simpler and less sensitive water ring pumps which create a vacuum using a rotating impeller, mounted eccentrically to the liquid ring. The liquid in circulation can be passed over a belt filter under atmospheric conditions. In this way, the maintenance of the system can be reduced to an absolute minimum.

During the procedure, the circulating fluid is heated. To prevent an increase in steam pressure, the liquid is circulated via a heat exchanger and kept at a constant temperature of roughly 10°C. The innovative design allows for simple heat exchanger cleaning while the system is running. While the MRS extruder is generally used for ordinary applications due to its low maintenance 25 mbar liquid ring vacuum system, unusual effects can be created by combining its intensive surface area exchange with deeper vacuums (e.g., 0.5 - 2 mbar). Gneuss also offers conventional solutions for such situations.


The control system is an essential component of any extrusion line. Today, a control system is expected to connect all line components into an efficient and user-friendly central system.Gneuss designed the MRS control system to take full advantage of all available measurement data and set points. The control system connects the numerous line components to a central operating system. Changes in the process are quickly identified and, if necessary, addressed. The production data is saved for further diagnosis or documentation, and the control system processes it to create trends with a history function. Working with the lean, user-friendly operating system is easy for most extruder operators, with no need for explanation. Only a few clicks on the touchscreen monitor are necessary to get the line into production.

Industry Applications


Sheet extrusion lines based on the Gneuss Processing Unit (GPU) are used in the production of PET sheet for thermoforming all over the world. Sheet extrusion lines based on the Gneuss Processing Unit (GPU) are used in the production of PET sheet for thermoforming all over the world. The applications range from monolayer sheet to liquid coated and laminated sheet made from 100% post-consumer bottle flake for food contact applications.


With this concept, production waste from fiber, film and start-up lumps are placed into a shredder and are transported via a conveyor belt with metal separator into an intermediate container with an agitator. From there, the material is conveyed into the extruder by means of an auger and a crammer feeder.

Alternatively, size-reduced and agglomerated waste can be directly fed into the MRS extruder. The advantage of separating the processing steps of size reduction and extrusion is that the material feed (and therefore the throughput rate) can be equalized and metals can be reliably ejected from the material flow, which is far more difficult to achieve on integrated systems.

The extruder melts the polyester waste gently and cleans the polymer of volatiles such as surface or absorbed water, spin finish oils and other spinning aids or printing inks (film waste) in the MRS devolatilising section. The intensive and highly efficient surface area exchange under vacuum ensures excellent performance. Solid contaminants such as glass, paper and ceramic are removed by the automatic, self-cleaning Rotary screen changer and the finely-filtered polymer melt flows to a pelletising system (chip cutter).

Optionally (for example when higher IV material is required) the polymer melt can be fed directly into the IV boost system JUMP to achieve an exact IV increase before being pelletised.

The pelletising / chip cutting system can be specified as an underwater strand pelletising process for cylindrical chips with subsequent crystallisation or alternatively, as an underwater die face cutting system for spherical chips with residual heat crystallisation. In this way, a high quality pellet / chip can be manufactured from up to 100 % industrial waste.


The demand for environment-friendly and economically sound production lines for synthetic fibers is increasing worldwide. The Extrusion System MRS fulfills both demands.

Gneuss extrusion lines are designed to produce high-quality fibre from PET post-consumer bottle flakes or production fibre waste in a variety of viscosities. Bicomponent (core/sheath, for example) staple fibre can be produced using the same input material and two different vacuum levels on two MRS extruders to provide two melts with varying viscosities to the spinning beam.The MRS extruder can also be used to convert bottle flakes or production waste into carpet fibre (BCF) and nonwovens, as well as bicomponent fibres. Raw material costs can be reduced by employing PET bottle flakes. Extrusion systems based on MRS can be integrated with any type of standard fibre downstream equipment.

Components and Functionalities


The RSFgenius provides unique possibilities in terms of achievable product quality, economic efficiency, and operator and maintenance friendliness. This fully autonomous and pressure-constant filtration system can be utilised in nearly any application for process automation and the manufacturing of high-quality end products. The RSFgenius is ideal for ultra-fine filtration, filtration of thermally sensitive melts, and filtration of materials with high contamination levels.


Within the JUMP reactor, the polymer passes across numerous slow turning components, forming a polymer film with a constantly refreshed surface. The reactor vessel is kept under vacuum, allowing ethylene glycol and other volatile chemicals to be evacuated reliably. The polycondensation process can be changed to get the desired product qualities by adjusting the residence time in the reactor, the vacuum, the fill level, and the speed of rotation of the agitation devices.

After passing through a stilling section in the reactor, the polymer melt is pumped either directly into the production process or into a pelletising (chip cutting) system.

The design of the JUMP prevents the ingress of oxygen, so discolouration (yellowing) of the polymer is minimized. Additionally, the JUMP is designed so that it is easily dismantled and the interior is easily accessible for cleaning.

The JUMP process is an extremely efficient alternative to a Solid State Polymerisation (SSP) as there is no energy needed to cool the polymer down and then reheat it. Further, the reaction time in the melt phase is considerably faster than in the solid phase, which also contributes to the better economics of the JUMP system. Last but not least, the JUMP offers advantages over an SSP in terms of space requirements and even maintenance.


The DA Series melt pressure transducers are utilised in the plastic production and processing sectors all over the world because of their excellent quality of craftsmanship and outstanding performance.Their extreme repeatability and consistent measuring values add to the accuracy of our measurements.

  • Application areas up to 400°C (750°F)
  • Pressure ranges from 0-50 and 0-2.000bar (0-725 and 29,000 psi)
  • Liquid filled measuring system
  • Maximum reliability through new membrane technology
  • Standard G-coating to counteract adhesive materials
  • 100% market compatible
  • Mercury free version available at no additional surcharge