Intermeshing Rotor Internal Mixers

1 Developments on the Original Francis Shaw Intermeshing Rotor 

Developments since the NR2 rotor have resulted in the NR5 rotors (305) which have improved cooling, achieved by incorporating what are effectively drillings into the rotor arranged so that virtually the full surface of the rotor is cooled just below the mixing surface. A modified rotor profile has been developed to allow an 

2 Intermeshing Rotor Developments at ThyssenKrupp Elastomertechnik GmbH 

A development on the PES-3 rotor was the PES-5 with significantly improved temperature control ability, and allowing even greater fill factors. This rotor predated the Francis Shaw NR5 rotor, and employed a similar arrangement of cooling passageways to allow cooling over the full surface of the rotor. 

3 Intermeshing Rotor Developments at Kobe Steel Limited 

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In the 1930s, there was a major innovation in the rubber industry with the invention of intermeshing rotor internal mixers. A June 1934 British patent... 

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... 

Various new designs of intermeshing rotor internal mixers have been proposed since the 1970s [33, 67 to 69]. In a 1987 patent application, Passoni [69] describes a design wherein the nip distance between the rotors may be varied. This allows the intensity of inter-rotor shearing to be varied during the mixer cycle for any particular compound and the shear intensity to be varied for different compoimd formulations. This machine is manufactured by Techint Pomini. 

In more recent years. Parrel Inc. has purchased Francis Shaw and Company. Intermeshing rotor mixers are also marketed by Techint Pomini and Krupp Gummitechnik, the successor company to Werner and Pfleiderer in producing internal mixers. Intermeshing rotor internal mixers are also made in Japan by Hitachi and Mitsubishi Heavy Industries. 

P. S. Kim and White [4,73] have sought to model flow in intermeshing rotor internal mixers and the optimization of rotor design. They have rated different machines described in the patent literature. 

Intermeshing rotor internal mixers - Mixers which are arranged sueh that the predominant mixing action is to shear the mixing eompound between the rotors of the mixer, and the distanee between the rotors is less than the rotor diameter. 

This article is written to update and assist compounders using the internal batch mixers and two-roll mills. The Coflow4 intermeshing rotor internal mixer has been shown analytically and experimentally to compound various materials better than all types of traditional uniflow geared intermeshing and partial-flow rotor internal mixers. 15 refs. 

Components of intermeshing rotor internal mixers are examined, and recent developments in rotor design and temperature control and hydraulically loaded plungers are reviewed. 

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. 

Variable Intermeshing Clearance (VIC) Rotor Internal Mixer... 

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. 

FI CU RE 35.12 Typical fingerprint of a masterbatch mixing process on an intermeshing internal mixer (GK 320E (Harburg Freudenberger) with PES5 rotors styrene-butadiene rubber/carbon black [SBR/CB] tread compound). 

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 4.30 Schematic of internal mixers with tangential or intermeshing rotors. 

Figure 1.6 Cook s June 14 1934 British patent application drawing for an internal mixer with intermeshing rotor. From Reference [43].

Figure 1.8 Post-Cooke intermeshing internal mixer rotors (a) Millauer[53] (b) Johnson etal. [54].

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

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