Design and Selection Factors

Before selecting solids-mixing equipment, a careful study ought to be made of several performance characteristics. As previously stated, mixing of 

Vertical screw mixers (a) central screw and (b) orbiting screw. 

Power requirements are not a major concern when choosing solids mixers since other considerations usually predominate. Sufficient power must be provided in order to handle the maximum needs, as well as to prevent changes during the mixing operation. When materials and operating conditions are subjected to variation, enough power should be made available for the heaviest bulk-density materials and for the extreme conditions of operation. If the loaded equipment is to be started from rest, there should be sufficient power for this. When speed variations may be desirable, this should be taken into account for power requirements planning. 

Dust formation should be avoided for safety reasons and when loss of dust may significantly affect batch composition. When dust release to the surrounding atmosphere caimot be avoided, the use of solid-gas separation 

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. 

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