Mixing applications Blending

Mixers, range of operation, 289 Chart to examine types, 296 Draft tubes, 309. 313 Flow patterns, 291 Jet, 325, 326 Selection guide, 289 Mixing applications, 288 Blending, 300 Gas dispersion, 325 Motion, 300... 

Dusts are also formulated as dust concentrates to reduce shipping costs. These concentrates may contain 25, 50, or even 90% toxicant. They can be diluted with cheap local diluents by a simple process of mixing or blending before application. Currently, dusts are not much used, because of their drift potential and inhalation hazard, and because of improvements in the other types of formulations. 

These determine the difficulty of the mixing application, as illustrated in Figure 9.41. The wider the viscosity difference between the component streams, the more difficult is the blending application. The most difficult application is the addition of a small, low-viscosity stream into a large, high-viscosity stream in laminar flow. For example, Tables 9.20(a) and 9.20(b) show effects... 

Another recent advance in PVDF technology involves coating applications using the acrylic-fluoropolymer lattices which are produced hy sequential polymerizations (see as given earlier). Initial reports indicate improved paint properties than heretofore produced by mixing and blending techniques (130). 

Eor practical reasons, and to facilitate data analysis, single-surfactant systems are normally studied. Importantly, the thermodynamic and kinetic models are easier to handle when compared with multicomponent systems, and there are only a few reliable methods for the unequivocal measurement of mixed systems. However, in real-world applications, mixed and blended surfactants are normally employed for commercial reasons and to improve performance. 

Other industrial applications of the concept include that for coating tablets in the pharmaceutical industry (Wurster et al., 1965), for drying of dilute solutions containing solids (Hadzismajlovic, 1989), and for mixing and blending (Decamps et al., 1971/1972 Matweecha, 1973 Solt, 1972 Krambrock, 1976). Both Conair Waeschle Systems and Fuller Company supply commercial blenders based on the concept. The concept was also proposed as a controllable solids feeder to a pneumatic transport tube (Decamps et al., 1971/1972 Silva et al., 1996). 

Of particular interest are the ternary systems of ethylcellulose dissolved in a mixed solvent (acrylic acid - water or acrylic acid - glacial acetic acid) and ethylcellulose/ acrylic acid solution blended with a flexible polymer, polyacrylamide. The conclusions of these studies is that, for cellulosic liquid crystals application, the morphology and optical properties of lyotropic liquid crystals can be adjusted by solvent mixing and blending with other polymers. 

Numerous research problems of practical and industrial importance and of theoretical and academic interest await solution in the preparation, characterization and application of ordered mixtures and composition-stable mixtures. Scant attention is paid here to these subjects because they are regarded as being outside the scope of bulk-solids mixing in the conventional sense, which usually is concerned with mixing and blending of free-flowing particles and powder in relatively large quantities. 

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