Internal mixer rotor designs

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

FIGURE 18 Internal mixer rotors from the designs of Sato et al [SI] of Bridgestone and Kobe Steel. 

There have also been new designs of internal mixer rotors, notably by MiDauer [53] of Werner Pfleiderer (Figure 1.8a) and Johnson et td. [54] of Francis Shaw (Figure 1.8b). Passoni [55] of Pomini has described a completely new design of intermeshing rotor internal mixer in which the rotor inter-axial distances may be... 

It became clear in succeeding years that the intermeshing internal mixer rotors did a better job of controlling the rubber temperature than F. H. Banbury s designs because of their higher metal surface areas. One was less likely to chemically damage expensive specialty elastomers with high temperature. 

The development of the tilt mixer is ontlined and tilt mixer apphcations are listed. The diflerences between the tilt mixer and internal mixer are identified and dalafiom compounding trials carried out on rubber formulations processed using the latest and most advanced tilt mixer rotor design (G-III Technology) introduced by Moriyama. 

Silica compounds are generally processed in conventional internal mixers, preferably with intermeshing rotors. These mixers are designed and optimized for carbon black-fiUed compounds in which mixing is based only on physical processes. When a silica-silane reinforcing system is used, additionally a chemical reaction, the sUanization, occurs. One of the main influencing factors of the silanization reaction is the concentration of ethanol in the compound as well as in the mixer [25,26]. As the silanization finally reaches an equilibrium, low concentrations of ethanol in the compound are expected to enhance the reaction rate. 

Fig. 20. Internal mixer design showing (a) cross-sectional view of constructional features and (b) typical rotor geometries [129]...

Fig. 22. Rotor designs for (a) single-stage and (b) two-stage continuous internal mixers [147]...

The factory system based on internal mixers, screw extruders, calenders, and vulcanization presses has remained basically unchanged in the past half-century. Internal mixers have had major improvements, e.g., intermeshing rotors proposed by Francis Shaw and Company [C16] and Werner and Pfleiderer [L3], and variable intermeshing clearance rotors [PI] proposed by Pomini-Farrel SpA. Sophisticated computer control systems have been introduced. The early single hot-feed extruders have been replaced by cold-feed extruders with increasingly sophisticated design including pin barrel extruders [G7, H12, H13, M18, W16] as well as complex control systems. 

Internal mixers with a much different mixing chamber design were proposed by Cooke [C17] of Francis Shaw and Company and by Lasch and Stromer [L3] of Werner and Pfleiderer. These internal mixers possess intermeshing counterrotating rotors (Fig. 1.9). In these internal mixers, both rotors must move at the same angular velocity. The Francis Shaw mixer, the Intermix, was marketed first and received considerable attention. In time, the intermeshing mixers dominated the mechanical rubber goods industries in Europe and Japan. 

FIGURE 17 F. H. Banbury s internal mixer and rotor design. (From Banbury [B12, B13].)... 

The widespread nse of internal mixers for polymer compounding over many decades, has resulted in many refinements to mixer, and particnlarly rotor design, together with optimisation of mixing procedures. 

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