Extrusion International 6-2023

57 Extrusion International 6/2023 TEMPERATURE CONTROL More Productivity and Quality in the Plastics Industry P1 cooling mixers from Promix Solutions can significantly improve existing extrusion and pelletizing processes but also polymer production processes. In principle, most processes in the plastics industry work without additional static cooling and the benefit of an additional installation is not obvious. However, reality shows that many industrial plants cannot be operated at maximum throughput. This is because more throughput usually means more friction and therefore higher melt temperatures. Higher melt temperatures lead to more product decomposition and to low viscosities, which makes processing more difficult and has a negative impact on product quality. Additional cooling can therefore make a big difference. B ut how to implement it? After all, cooling viscous plastic melts, which are usually sensitive to decom- position, is a challenging task. Due to the increase in vis- cosity caused by cooling, the plastic melt to be cooled tends to adhere and form deposits on the cooled sur- faces. The result is long residence times and undesir- able product decomposition, exactly what one actually wants to avoid. The Promix P1 static cooling mixer technology makes all the difference. As the name implies, it is a combina- tion of an optimized static mixer with a high-perfor- mance melt cooler. The sectional drawing (Picture 1) illustrates the unique principle. The optimized mixer structure installed in the interior of the cooler causes highly efficient mixing of the melt over the entire cooler cross-section. At the same time, however, the mixer structure also serves as a heat ex- changer, and this without any additional internals that would disturb the mixing performance. After all, mixing is the key to success. The melt hitting the cooling surfac- es is constantly and immediately removed by the unique structure and replaced by new hotter melt. The forma- tion of deposits and product decomposition is no lon- ger possible. The continuous renewal of the boundary layers between the cooling surface and the melt results in an exceptionally high cooling capacity with minimum size. The design also makes the cooling mixer practically non-destructible and very durable. Accordingly, Promix P1 cooling mixer technology is becoming increasingly popular in a growing number of applications. Originally developed for the lightfoam sector, the technology is now also being used success- fully in classic plastics processing, in pelletizing process- es, in the fiber industry, in polymer production, and in the chemical/pharmaceutical/food sector. P1 cooling mixers are available in various sizes, from pilot applications with throughputs of 5 - 10 kg/h, up to production plants with more than 20,000 kg/h. The experience enables a safe scaling of the results from laboratory scale to the production plant. Test cooling mixers allow a quick and safe start. In addition to a wide standard program, cooling mixers can also be built from special materials and for pressures up to over 400 bar, to meet the requirements of the individual application. Promix Solutions AG Technoparkstr. 2, 8406 Winterthur, Switzerland www.promix-solutions.com Sectional view of a P1 cooling mixer: The mixer structure ensures highly efficient mixing of the melt over the entire cooler cross-section. At the same time, the mixer structure serves as a heat exchanger. Promix P1 Fiber Cooler