Mechanical mixing equipment

The purpose of this chapter is to introduce the reader to the factors governing the selection and design of mechanical mixing equipment for use in low viscosity Newtonian liquids. It does not attempt to turn the reader into a design expert, rather to ensure that he or she is provided with sufficient information to conduct a sensible conversation with equipment designers, suppliers or users. 

These processes depend on fluid shear for coagulant dispersal and for promoting particle contacts. Shear is most commonly introduced by mechanical mixing equipment. In certain solids contact processes shear results from fluid passage upward... 

The commonly used types of mixing equipment can be placed in the broad categories (1) mechanical agitators, (2) inline motionless mixers, (3) tank jet mixers, and (4) miscellaneous. The nature and type of agitator used depends upon the scale and type of mixing and upon the fluids being mixed. The broad classes of impellers are ... 

The processing technologies for elastomeric blends, thermoplastic elastomer-based on mechanical mixing, and elastomer-plastic vulcanizates are distinctly different. Depending on the type and nature of blend, size, and their final application, a wide range of processing equipment is now in use both industrially as well as in laboratory scale preparation. 

Dickey DS, Fasano JB. Mechanical Design of Mixing Equipment. In Paul EL, Atiemo-Obeng VA, Kresta SM, eds. Handbook of Industrial Mixing Science and Practice. Hoboken, NJ Wiley, 2004 1308. 

There are no standard engineering classification methods for mixing equipment, and often, quite different types of mixers can fulfill the same mixing task. Nevertheless, we can subdivide mixers used in processing into three broad categories particulate solids mixers, laminar distributive mixers, and laminar dispersive mixers. This classification, on the basis of application, is supported by the nature of the primary mixing mechanism taking place in them. 

Short-circuiting is one of the major problems associated with mechanical aeration equipment. Combined mechanical- and diffused-aeration systems have enjoyed some popularity for industrial-waste systems that treat variable organic loads. The mechanical mixers provide the fluid mixing with the diffused aeration varied for different oxygen-transfer rates. 

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