Mixer blades shearing path

Fig. 2 Shearing path of mixer blades through wet mass at capillary state. (From Ref John Wiley and Sons, Inc.)...

Pan mullers are the modern industrial equivalent of the traditional mortar and pestle. Typical mullers have two broad wheels (Ml and M2) on an axle (Fig. 18-54). The mixer rotates about the approximate midpoint of the axle, so that the wheels both rotate and skid over the bottom of the mixing chamber (A). Plow blades (PI and P2), which rotate with the mixer, push material from the center (T) and walls (C) of the mixing chamber into the path of the rollers. The mixing action combines both crushing and shearing to break lumps or agglomerates and evenly distribute moisture. 

The corn mill is a long established high shear mixer and has a logical extension in the edge-runner mill (Figure 3.10), where weighted rotating mill wheels shear the powder in the base of a static cylinder. Scraper blades are essential to reposition the powder back into the path of the wheels. 

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