Mixer selection

Mixer selection and design Number of mixers Number of mixers... 

Only seldom can a mixer selection be made solely on the basis of the mixture quality achieved in a series of isolated tests. Generally, a compromise has to be reached between mixture quality and the compatibility of the different mixer types with a process. An initial selection eliminates those mixers which are incompatible. 

If more than one mixer can be found that satisfied both the process and the mixture quality requirements then it is likely that a final mixer selection will be based on the unit costs of mixing. 

Figure 3.15 Mixer selection decision chart (based on Schofield and Miles )...

Dry powder mixers should be selecfed or designed for a particular operation, firstly by analyzing and giving careful examinations to the applicable areas discussed above. Mixer selection should also involve consideration of the place of the mixer within the overall process. Possible integration of many steps within the overall processing of solids in a particular application deserves scrutiny at this time. If there is no machinery available including all the necessary requirements, consideration should be given to modifications in order to obtain the most desirable features combination of the equipment. 

The performance of stirred vessels is characterized on the basis of the process resnlt for the mixing operation. Detailed mixing mechanisms and design criteria are discnssed in respective chapters for these mixing operations. In this section we cover only the general principles and mixer selection for different ranges of fluid properties. 

There are numerous factors that govern the successful mixing of bnik sohds. Although it is difficult to make a complete and absolutely comprehensive list, there are several key process questions that deserve attention prior to mixer selection. 

Some common questions pertaining to sampling encountered during mixer selection and performance evaluation are ... 

Kent, M. (2002). Mixer selection an aid to those involved in the selection, specification and purchasing of mixing machines. Powder Handl Process., 14(1), 41-43. Krambrock, W. (1976). Mixing and homogenizing of granular materials in a pneumatic mixer unit. Powder Technol, 15, 199-206. 

Muskett, M. J., and A. W. Nienow (1987). Capital and running costs the economics of mixer selection, in Ruid Mixing HI, Inst. Chem. Eng. Symp. Sen, 108, 33-48. 

Experience in scale is also important. Mixing applications range from small processes requiring portable-size mixers to large processes involving millions of liters, such as those in the minerals processing industry. Considerations for mixer selection vary by scale, so it is essential for the equipment supplier to have experience in applications of all sizes, as well as proven success in process scale-up. 

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