Bin blender

Fig. 15. BINSERT in-bin blender. The hopper walls are chosen to cause a significant velocity differential center to the outside.

Common violations of this approach that can immediately cause problems include the attempt to scale from one geometry to another (e.g., V-blender to in-bin blender), changing fill level without concern to its effect, and keeping blending time constant while changing blender speed. 

Sudah O, Coffin-Beach D, Muzzio FJ. Quantitative characterization of mixing of free-fiowing granular materials in Tote(Bin)-blenders. Powder Technol 2001, to appear. 

Figure 9.13 On-line blender configurations (a) Bin blender (b) Y-cone blender configuration. Reprinted from Hailey etal. (1996)79 with permission from Elsevier.

Duong, N.-H. Arratia, P. Muzzio, F. etal., A homogeneity study using NIR spectroscopy Tracking magnesium stearate in Bohle bin-blender Drug Dev. Ind. Pharm. 2003, 29, 679-687. 

Figure 7.6 Tumbling bin blender with an intensifier bar. (Courtesy of Patterson-Kelley Co., Pennsylvania.)...

The unit formula of example 3 is listed in Table 7.14. The batch size manufactured was 10 kg. The API was preblended with Avicel PH101 using a Patterson-Kelly tumble bin blender equipped with an intensifier bar (0.5 ft3, Fig. 7.6) at 15 rpm with the intensifier bar speed of 2000 rpm for 15 min. The preblend was mixed with lactose, sodium starch glycolate and colloidal silicon dioxide in a 1 ft3 tumble... 

Characterization of performance of bin blenders. Part 1 of 3 Methodology. Pharm. Technol. 28(5) 70-86. 

Carson (2002) mentions that inserts have been placed within the hopper to expand the size of the active flow channel and/or to relieve pressure at the discharge. Inverted cones and pyramids have been used with hmited success. He suggests a hopper within a hopper so that material flows in the area between the inner and outer hoppers and through the inner hopper if it does not have a cover on it. By proper design of the geometry of the hopper, a uniform velocity profile can be achieved such that there is a minimum amount of particle segregation. Sometimes in-bin blenders have also been used for this purpose. 

Fig. 6 Three common tumbler designs (A) double-cone, (B) V-blender, and (C) tote, or bin blender.

The tangential speed of the blender (linear velocity) is another approach that is used for the scale-up of the blending process, mainly for blenders of similar geometry. The linear velocity can remain constant by adjusting the speed of rotation as the size of the mixer is changed. Table 8 gives an example of the change in rotation speed that is applied to keep the linear velocity constant within a family of bin blenders. 

Table 8 Comparison of linear velocity for bin blenders of varying size...

Osama, S.S. Coffin-Beach, D. Muzzio, F.J. Quantitative characterization of mixing of free-flowing granular material in tote (bin)-blenders. 2002,126, 191-200. 

Whenever possible the number of material transfer steps should be minimized. With each transfer step and movement of the bin or drum, the tendency for segregation increases. Ideally, the material would discharge directly from the blender into the tablet press feed frame with no additional handling. In-bin blending is as close to this as most firms can practically obtain, and is the best one can ask for, as long as a uniform blend can be obtained within the bin blender in the first place. Another way to minimize material transfers is to use continuous blending operations that directly feed material to the compression or filling equipment. 

Tumble blenders V-blenders Bin blenders DcHible cone blenders Slant cone blenders Horirontal/vertical/drum blenders... 

Sudah, O Anatia, P, Coffin-Beach, D, et al. Mixing of cohesive pharmaceutical formulations in Tote (bin) blenders. Drug Dev Ind Pharm 2002 28(8) 90S-1. ... 

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