Internal mixer tangential

An analysis of the flow behavior which is more or less confirmed by numerical simulations is presented by Leblanc. " The total flow in an internal mixer (tangential type) can be divided into a laminar, circulating flow which is pushed by the rotor tip, an axial directed flow, as an effect of the helix angle between axis and rotor wing and a leakage flow between rotor tip and mixing chamber waU (refer to Figure 35.6), or... 

Figure 8 Internal mixer rotor designs (a) tangential rotor, (b) intermeshing rotor.

Basically two rotor types are applied in the internal mixer The tangential rotor type and the intermeshing rotor type. The latter one interferes with the adjacent rotor and turns at the same rotor speed compulsory. In the drop door or through the side plates a thermocouple is mounted to record the temperature of the mbber. 

The material flow in an internal mixer is oriented vertically. On top of the internal mixer a more or less sophisticated feeding system can be found. Underneath the mixer a downstream device, such as a sheeting extruder with one or two tangential screws, or two roll mills are placed. 

It is well known that the cycle time of the mixing process in an industrial-sized internal mixer is limited by the increase of the compound temperamre. For example, typical mixing times on a 400 L tangential mixer with four wing rotors is of the order 200 s as can be derived from Figure 35.2. Especially during the last mixing phase the temperature increase of the compound is approximately l°C/s. 

Internal mixers are made in two types tangential and intermeshing. Banbury mixers are the most popular and they are tangential mixers. ... 

FIGURE 4.30 Schematic of internal mixers with tangential or intermeshing rotors. 

Differences in Behavior Between Internal Mixers with Tangential Rotors and Intermeshing Rotors, as Influenced by the Molecular Structure of EPDM... 

As a tangential rotor type mixer, a Werner and Pfleiderer GK-2 internal mixer was used with a chamber volume of 3150 cm. The mixer was operated at a fill factor of 76%, the optimum with regard to mixing efficiency for such a type mixer. Rotor speeds of 46 and 50 rpm were used, running at a friction factor of 1.1. A ram pressure of 5 bars (maximum oil pressure on the plunger of the ram) and a wall temperature of 40°C held constant throughout the mixing cycle. 

The analogy of the mixing behavior of EPDM rubbers with different molecular structures in internal mixers and their behavior on a two-roll mill, applies to tangential as well as to intermeshing type mixers. 

Wiedmann and co-workers studied heat generation and heat transfer in tangential internal mixers and showed that the important factor is contact surface between the compound and the wall. They... 

AEM compounds can be mixed in internal mixers, intermeshing and tangential, or on a mill, with relatively short mix cycles. The guiding principle when mixing AEM compounds is to keep the polymer temperature as low as possible initially to increase mixing times. 

Tangential rotor internal mixers - Mixers which are arranged sueh that the predominant mixing aetion is to shear the mixing eompound against the sides of the mixer. 

Friction ratio - The ratio between the differences in rotational speed of two rotors in a tangential internal mixer, or between the rolls of a two-roll mill. 

Technical featiues of the MCC series of tangential rotor internal mixers developed by Comerio Ercole are described. 

The feamres and technical benefits of the Hagglunds drive concept for tangential internal mixers are described. The drive concept with power unit and hydraufic motor directly mounted on the machine is illustrated and white area analysis data from three different samples produced in an internal mixer equipped with an adaptive drive concept, called Maximum Rotor Control, and in a internal mixer utilising standard settings with a fixed rotor speed ratio, are presented and discussed. 

An overview of the mixing machinery cmrently available for the manufacture of silica compounds and the requirements for the design of an internal mixer for the production of these compotmds is presented. A comparison is made of different mixers and the replacement of a 270-litre tangential mixer with a250-litre intermeshing mixer to make use of the advantages of mtermeshing irrtemal rrrixers is demonstrated. 12 refs. (International Tyre Exhibition Conference, Akron, USA, Sept. 12-14, 2000). 

The friction ratio between the rotors of a tangential-type internal mixer as a possible control parameter for the mixing process is studied and discussed. No refs. POMINl... 

The frietion ratio between the rotors of tangential mixers is examined as a parameter for the control of the mixing process. Reference is made to internal mixers developed by Meccaniche Modeme in collaboration with Kobe Steel. MECCANICHE MODERNE SPA KOBE STEEL LTD. POMINI... 

A survey is made of trends in internal mixers for use in the rubber industry, and developments by Krupp Elastomertechnik and some other leading machinery manufacturers are examined. Aspects discussed include the operation of tangential and intermeshing rotors, wear resistant materials for mixer components, the replacement of pneumatic rams with hydraulic rams, optimisation of the mixing process through the use of variable speed drives, and developments in mixing technology for the preparation of silica filled tyre tread compotmds. 20 refs. 

The internal mixers are made in two types, one is tangential and the other is intermeshing [12]. Most widely used in mixing rubber are Banbury mixers (see Figures 1.4a and 1.4b), which are tangential. An intermeshing type is shown in Figure 1.4c. 

First, mixing of these materials may be very different from what has been described so far. For example, the internal mixer described here is primarily a tangential type. For many of the new materials an intermeshing type may offer an advantage. Also, use of a twin-screw and continuous mixing may be a preferred choice. 

Hardt, S., Dietrich, T., Freitag, A., Hessel, V., Lowe, H., Hofmann, C., Oroskar, A., Schonfeld, F., Vanden Bussche, K., Radial and tangential injection of liquid/liquid and gas/liquid streams and focusing thereof in a special cyclone mixer, in Proceedings of the 6th International Conference on Microreaction Technology, IMRET 6 (11-14 March 2002), AIChE Pub. No. 164, New Orleans, 2002, 329-344. 

An investigation was carried out into the incorporation and dispersion of fillers into mbbers. Factors contributing to the dispersion of fillers into mbber were examined and the disadvantages of tangential-type mixers and intermeshing-type mixers for incorporating fillers into mbbers indicated. 8 refs. Articles from this journal can be requested for translation by subscribers to the Rapra produced International Polymer Science and Technology. 

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