Foam Generation in Rotor-Stator Mixers

One of the unit operations in foam technology is foam generation in a liquid/gas mixer. The foaming process of an aqueous liquid system with a surface-active agent in a rotor-stator mixer has been studied, and it was found that it could be represented by a mixing characteristic relating the liquid flow rate to the maximum gas flow rate needed to produce a foam without ‘blow-by’. Too high a gas flow rate resulted in a short-circuiting flow of gas via the rotor shaft to the outlet. The influence of the number of rotor-stator blades, equipment size and operating pressure on the behaviour of the foam has been investigated