Double-cone blender

Sohd—sohd blending can be accompHshed by a number of techniques. Some of the most common iaclude mechanical agitatioa which iacludes devices such as ribboa Headers, impellers, paddle mixers, orbiting screws, etc a rotary fixed container which iacludes twia-sheU (Vee) and double-cone blenders and fluidization, ia which air is used to Head some fine powders. 

Brone D, Muzzio F. Enhanced mixing in double-cone blenders. Powder Technol 2000 110(3) 179M89. 

Sethuraman KJ, Davies GS. Studies on solids mixing in a double-cone blender. Powder Technol 1971 5 115-118. 

Charge in a suitable stainless steel double-cone blender, sucrose, sodium phosphate, xanthan gum, sodium cyclamate, sodium saccharin, gly-camil, and starch pregelatinized. 

Figure 10.15. Some mixers and blenders for powders and pastes, (a) Ribbon blender for powders, (b) Flow pattern in a double cone blender rotating on a horizontal axis, (c) Twin shell (Vee-type) agglomerate breaking and liquid injection are shown on the broken line, (d) Twin rotor available with jacket and hollow screws for heat transfer, (e) Batch muller. (f) Twin mullers operated continuously, (g) Double-arm mixer and kneader (Baker-Perkins Inc.), (h) Some types of blades for the double-arm kneader (Baker—Perkins Irtc.).

Fig. 11 Axial segregation in top views of double-cone blender from (A) experiment and (B) particle-d5mamic simulation using large (light) and small (dark) spherical grains. Similar patterns are seen in other tumbler designs, for example in the V-blender in (C) experiment and (D) simulation.

Fig. 23 High-resolution data are obtainable by solidifying and slicing an entire blend, here of identical but colored 90-pm grains in a double-cone blender.

Fig. 24 X-ray tomographic time series of blending of radioopaque grains in double-cone blender is representative of several new techniques available for on-line and in situ assays of blending mechanisms.

These techniques are typically expensive and cumbersome to implement nevertheless they reveal flows within an optically opaque bed and provide valuable information not attainable otherwise. For example, in Fig. 24, we display results of x-ray tomography experiments that show the evolution of the interior mixing structure within a double-cone blender using molybdenum-doped tracer particles (dark in Fig. 24). These experiments represent a scaled-up version of the solidification data shown in Fig. 23 the capacity is 8 times larger ( 4.8 L vs. 0.6 L), and the particle diameter is 18 times larger ( 1600 vs. 90 pm). Data of this kind reveal a complexity in flow and mixing evolution that simultaneously represents the cause of historical difficulty in understanding the subject and the opportunity for future developments. 

Chester, A.W. Kowalski, J.A. Coles, M.E. Muegge, E.L. Muzzio, E.J. Brone, D. Mixing dynamics in catalyst impregnation in double-cone blenders. Powder Technol. 1999, 102, 85-94. 

FIGURE 26 Double cone blender. Source Courtesy of Patterson-Kelley. 

FIG. 21-157 Examples of low-shear mixers used in granulation, (a) Ribbon blender (h) planetary mixer (c) orbiting screw mixer (d) sigma blender (e) double-cone blender with baffles (/) v blender with breaker bar. (See also Solids Mixing. ) [( ) and (d), Chirkot and Propst, in Parikh (ed.). Handbook of Pharmaceutical Granulation Technology, Taylor 6- Francis, 2005.]... 

The two components (W and C) must be blended thoroughly prior to carburization. This is done in different types of equipment, like V or double cone blenders, mixing ball mills, or high-energy mixers. An even blend is of importance because, during carburization, carbon atoms can only move via diffusion or as methane molecules over very short distances. Pelletizing or compacting enhances diffusion and increases the furnace capacity. 

Fig. 23. Illustration of how confidence limits computed from a Poisson distribution can be used to evaluate blender performance. Double cone blender, 500 turns. Natural polythene (rough 4 mm. cubes, sp. gr. 0.92) mixed with master batch containing carbon black (3 mm. cubes, sp. gr. 1.2). Conclusion batch not randomly mixed since probability of this graph occurring with a randomly mixed batch isless than 0.01 (Al).

Fig. 11.13 Photograph of different tumble/growth agglomeration work modules that are attached to the all purpose drive stand of Fig. 11.12. (a) disc or pan agglomerator (b) coating pan (c) bowl blender (d) planetary bowl blender (e) double cone blender (f) cube mixer (g) high shear mixer (h) pug mill/kneader (courtesy Erweka, Heusenstamm, Germany).

Fig, 6-19. Installed cost of rotary double-cone blenders (ENR = 750). 

---