Extrusion International 1-2017

31 Extrusion International 1/2017 High-performance mixer aspiration ensures constant process conditions www.mti-mixer.de Little or no deposits minimise the time and cost of clean- ing the mixing system and all additional equipment, while a constantly high product quality reduces scrap. Together, these three benefits can provide significant cost savings and extended maintenance intervals, thereby resulting in a clearly increased availability of the entire production line. Closed-loop control for constant drying performance More traditional aspirator systems would not take into ac- count changing process parameters but instead activate/ deactivate the exhaust air system as dictated by the pro- cess, with filter cleaning being performed at fixed pre- defined trigger points. This approach is typically linked with disadvantages such as diminishing air output due to progressive filter contamination, causing quality variations in the final product. MTI Mischtechnik’s Vent tec ® 2.0 aspi- ration systems, in contrast, continuously monitor all actual operating conditions via key parameters such as intake air and system air temperatures, air pressure, humidity and, with high significance, the aspiration air flow rate. Their electronic controller continuously analyses these variables and adjusts the aspiration system accordingly with due regard to the filter status, keeping aeration airflow con- ditions constant. In addition, the system reports incipient wear of the process filter at an early stage, thereby al- lowing preventive maintenance to be carried out. Thus, Vent tec ® 2.0 aspirator systems are key to both constantly high drying performance and product quality. Main applications include the production of rigid and soft PVC dryblends and natural fibre compounds (WPC/NFC/ PPC) as well as thermal processes where Vent tec ® 2.0 de- vices serve to dehumidify the mixture and/or to reduce the volatiles content. The new generation aspirator systems are available in various sizes for all mixing volumes and accom- modating nearly all ATEX environments and mixer designs. Thanks to their autonomous control technology, they can also be retrofitted on other manufacturers’ machines. Prevents deposits, saves time and cost At process temperatures markedly exceeding the boiling point of water, even low humidity levels may interfere with the process. This is even more relevant for PVC recipes containing hygroscopic stabiliser systems. Without a high- performance aspiration capability, the result may often be massive deposits on the interior surfaces of heatingmixers, cooling mixer walls and extruder dies, as well as in calibra- tion devices. The potential consequences may include a diminished mixing quality, extruder problems and fluctua- tions in the final product. In all such situations, Vent tec ® mixer aspiration technology by MTI Mischtechnik provides the necessary uniformly high dehumidification rates for constant production results. Compensating effectively for variations in raw material moisture and seasonal influ- ences on the processing properties of the mixture, these systems provide an unvaryingly high dryblend quality with ultimate humidities ranging down to below 0.05%. For the manufacturer, this high performance leads to com- pelling advantages. Thus, an almost fully dehumidified dry- blend will permit a high output of downstreammachinery. With the launchof Vent tec ® 2.0,MTIMischtechnik presents a newgenerationof its provenhigh- performance aspiration systems for heating/cooling mixer combinations. Unlike conventional solutions, these devices are the first ever to control their operation autonomously as a function of actual process parameters, thereby providing constant processing conditions irrespectively of changes in process and ambient conditions. Accordingly, they significantly facilitate the task of maintaining uniformly high product quality in the plastics processing and chemicals industry. Unlike conventional systems, the new Vent tec 2.0 high-performance aspiration systems for heating/cooling mixer combinations control their own performance independently as a function of actual process parameters. They are thus key to achieving constantly high product qualities in the plastics processing and chemical industries PERIPHERY