Other Batch Mixer Developments

Described in the last Review Report, this does not appear to have taken the rubber industry by storm, probably due to the complexity of operation and limited applicability in highly viscoelastic materials. The imit has imdergone further development (234,233), but would appear more suitable to preparation of low viscosity materials and materials with very little elastic element. 

2 Watson-Brown Limited High Stress Mixers (HSM) 

---

A final mixing system worthy of mention is that used by the Canadian Armament Research and Development Establishment and Bristol-Aerojet, which is a horizontal ribbon mixer. In this case, the blades carry the material from the center to the ends of the mixer and return it by internal spirals along the center shaft. This mixer is noted for its rapid incorporation of solids and the ease by which material is discharged as compared with the other fixed bowl, batch mixers. A comparison of typical batch mixers is shown in Table II. 

Other common continuous mixers involve substantial modification of single and twin screw extruders, aimed at improving distributive mixing capability in particular, and leading to the development of continuous mixers such as the Transfermix (50) and the Buss Ko-Kneader (51). Another approach in continuous mixer development is to transform batch mixers into continuous ones. Thus, the roll-mill can be converted into a continuous mixer by feeding raw material on one side and continuously stripping product on the other side. In addition, the Banbury mixer was imaginatively transformed into the Farrel Continuous Mixer (FCM) by Ahlefeld et al. (52), and, later, two similar continuous mixers were developed by Okada et al. (53) at Japan Steel Works and by Inoue et al. (54) at Kobe Steel. 

An integrated micro device containing a mixer was developed for biochemical experiments [106, 107]. For amplification reactions the handling of very small volumes (< 10 pi) of DNA and RNA under non-batch conditions was required. Thus, the key issue for design of the mixer was to minimize the volume of the components of the micro device, thereby, among other things, stimulating the development of a micro mixer with reduced dead volume. 

---