Batch Size Increase in Dry Blending and Mixing

In the manufacture of many pharmaceutical products (especially tablets and capsules), dry particle blending is often a critical step that has a direct impact on content uniformity. Tumbling blenders remain the most common means for mixing granular constituents in the pharmaceutical industry. Tumbling blenders are hollow containers attached to a rotating shaft; the vessel is partially loaded with the materials to be mixed and rotated for some number of revolutions. The major advantages of tumbling blenders are large capacities, low shear stresses, and ease of cleaning. These blenders come in a wide variety of geometries and sizes, from laboratory scale (16 qt) to full-size production models (500 ft3). A sampling of common tumbling blender geometries include the V-blender (also called the twinshell blender), the double cone, the in-bin blender, and the rotating cylinder.