Mixing equipment mechanisms

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 ... 

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. 

Mixing of the mixed liquor is also accomplished by the aeration system. The mixed liquor solids must be kept in suspension for proper operation of the process. The mixing requirement depends on types of aeration equipment, depth, and width of the tank. Typically, a mixed liquor velocity of 0.15 m/sec in the aeration tank provides adequate mixing. For mechanical aerators, power input of 16-30 W/m is often specified for mixing of biomass in the tank. ... 

In dealing with the problem of mechanical stress one has to distinguish between the aspects which concern device construction and those which are of concern to the device users. Information over the mechanical forces, which operate on the stirrer, the shaft, the shaft bearings and the shaft seal, together with the critical stirrer speed etc., can be obtained from the brochures of the stirrer manufacturers [0.14, 526] and from research papers such as [123, 393, 420]. In this section only those aspects which are of interest to the comparatively large group of users of mixing equipment will be considered. 

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