Early Developments of Co-rotating Twin Screw Extruder Part II

In the early 1940s, a systematic investigation into the co-rotating extruder system began at the IG plant in Wolfen. It involved the combined physical, mathematical, engineering and mechanical expertise of a team composed of W.Meskat, A. Geberg, R. Erdmenger and their staff. The team was commissioned to develop a reliable “mechanical apparatus” for chemical processes with highly viscous products.

The work was continued at some company in Leverkusen with strongly process-orientated groups under the new “applied physics” (AP) organizational structure introduced by K.Riess and implemented by K. Sigwart in 1948. R. Erdmenger founded and led one of these engineering groups, which was composed of 10 to 15 specialists and employees, until 1976. The group was later given the name “High Viscosity Technology”.

Naturally this team, part of the chemical industry, was primarily involved with solving problems in the area of high-viscosity engineering, particularly in developing chemical processes for that company. The mechanical aspect was developed as required and to varying degrees of intensity.

With respect to screw geometry, we turn back the clock to Wolfen, where the team was searching for the perfect mechanical apparatus for high-viscosity technology. It had to function despite the adhesive, frictional, and anti-frictional properties of the product, cope with various material consistencies, and overcome rheological changes caused, for instance, by reactions in the machine.

The desired self-cleaning function led to the development of the intermeshing twin screw. The counterrotating screw was discarded, because it tended to get blocked by solids and was a poor mixer; attention focused instead on the intermeshing, co-rotating extruder.