Scale-up of Batch Rotor-Stator Mixers. Part 1 – Power Constants

Rotor-stator mixers are characterized by a set of rotors moving at high speed surrounded closely by a set of stationary stators which produces high local energy dissipation. Rotor-stator mixers are therefore widely used in the process industries including the manufacture of many food, cosmetic and health care products, fine chemicals, and pharmaceuticals. This paper presents data demonstrating scale-up rules for the key power parameters; laminar power constant, Metzner-Otto constant, and Turbulent power number; for Silverson Batch rotor-stator mixers. Part 2 of this paper explores mixing times, surface aeration, and equilibrium drop sizes. These rules will allow processes involving rotor-stator mixers to be scaled up from around 1 litre to over 600 litres directly.