With increasing use of single-use, disposable fluid processing systems, concerns for mixing arise in processes such as protein concentration, clarification and diafiltration. For some operating conditions of flow rate, solution viscosity or flow path configurations, protein solutions may become stratified in vertically-oriented hanging bags. This can cause decreased efficiency in cross flow applications.
In this study, we modeled a stratified solution and tested the influence of these various operating conditions using ReadyCircuit™ 2-D pillow bags. Even with viscous materials, flow path configuration, and the relationship of bag volume to recirculation flow were important determinants of adequate mixing. These conclusions are supported by visual and mixing time data.