Mixing Mechanics: Batch blender selection: Some insights
Effective batch blending can be accomplished by many different blenders. If your company's product line is diverse, you probably don't have the luxury of having the best blender for every product. But you know that to produce a high-quality product, it's important to choose the best overall blender. In this column I'm going to give a brief overview of three batch popular blender types the tumble blender, the impeller-driven blender, and the multiple-shaft blender. All of these blenders are low-shear blenders commonly used in batch processes. I'll briefly describe each blender's configuration and blending mechanism, then list some of the factors you should think about when you're considering buying a blender.
The tumble blender is an enclosed, rotating shell mounted on legs. The shell may be V-shaped, double-cone-shaped, or rectangular. The shells end-over-end rotation gently tumbles the ingredients to produce a blend. This gentle mixing action can be important when you want to limit particle breakage, such as with pharmaceuticals and other friable materials. However, the tumble blender has a greater tendency to demix than impeller-driven and multiple-shaft blenders.