Process Equipment Update


 As the latest developments show, reliability, flexibility, ease of use and safety are the watchwords for modern mixing systems. Sean Ottewell reports.


 Die neuesten Entwicklungen zeigen, dass Zuverlässigkeit, Flexibilität, Benutzerfreundlichkeit und Sicherheit bei modernen Mischsystemen entscheidend sind. Sean Ottewell berichtet.


 Comme le révèlent les dernières avancées, la fiabilité, la flexibilité, la simplicité d’utilisation et la sécurité représentent les mots d’ordre des systèmes de malaxage modernes. Par Sean Ottewell.


Reliability and flexibility at heart of mixer advances


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Fig. 1. Uni tec can be optimally adapted to specific application needs – from gentle homogenisation of the most sensitive starting materials to the pre-dispersion of cohesive pigments.


ni tec is a newly developed, individually designed general- purpose mixer provided by MTI Mischtechnik for manually or fully automatically controlled preparation


of bulk materials in the process industries. Depending on its configuration, uses of the new


mixer unit range from homogenising bulk stock of diverse material characteristics to performing complex processing cycles aimed at providing specific product properties. The design criteria of the mixing vessel, mixing


tool and optional chopper systems are variable over a very broad range. As a result, the unit can be optimally adapted


to specific application needs - from gentle homogenisation of the most sensitive starting materials to the pre-dispersion of, for example, cohesive pigments (Fig. 1).


Spraying systems for fluids Further options - including spraying systems for fluids, a double jacket for temperature-controlled process management, and a vacuum-proof or pressure shock resistant design of the mixing vessel - are available to handle coating and granulating tasks with high accuracy and repeatability. Thanks to the operator-friendly design of the


new Uni tec universal mixer, it ensures convenient filling, evacuating and cleaning in every situation. “The new Uni tec system


combines high ease of use, maximum process reliability and safety, as well as application-focused configurability in one single unit. This standard- setting combination enables users to obtain high-quality mixing results with remarkably superior efficiencies compared to most conventional mixers. Needless to say, MTI’s products conform to all applicable codes and regulations including ATEX


requirements according to the


raw material property specifications. The Uni tec control system and the safety technology employed meet all demands on advanced,


flexible production equipment performing to the highest quality standards,” said MTI ceo Christian Honemeyer. Apart from the new Uni tec universal mixer,


MTI’s product range comprises an easy-to-clean horizontal mixer, the application-focused MTI Flex-line and MTI Eco-line heating-/cooling mixer combinations, and highly efficient dehumidification and aspiration systems. In late 2010, the company launched its Cool


tec mixer, pioneering direct cooling by means of a refrigerant rather than with cooling water. According to MTI, the technology has been widely acclaimed for its much enhanced cooling performance and concurrently reduced energy demand.


Conical blenders The concept of a conical-shaped vessel fitted with an orbital rotating screw was developed by the Dutch company Nauta many years ago and now, as part of the Hosokawa Micron worldwide group, these blenders are able to carry out complex processing tasks in addition to a blending operation. For example, the addition of a small, high-speed


rotating paddle (intensifier) in the vessel means that small quantities of liquids, waxes or chemicals can be efficiently blended into the main powder bulk. Coated products can also be produced. Other additions include jacketed vessel walls for heating or cooling operations and designs where there is no bottom bearing for the orbital screw, which makes for easy cleaning and minimises cross contamination. Application of vacuum to the vessel and slight


changes to the design enables the Vrieco Nauta mixer to become a vacuum dryer, hence mixing and drying can be carried out in one processing vessel. This range of conical vacuum dryers, developed


from the basic conical mixer, is now one of the most respected dryers in industry. Based on the design of the conical mixer,


Hosokawa Micron’s Cyclomix is a smaller, highly efficient intensive mixer developed to handle cohesive powders. The mixing element is a fast rotating set of paddles fitted to a central shaft and the real intensive high shear mixing action is generated in the small space between the paddle tip and vessel wall. Tip speeds up to 30m/s are possible. The conical vessel shape ensures the material moves upwards and falls down again guided by the vessel cover down into the base for more processing.


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