Microbubble generator

Means are provided for supplying a liquid surfactant solution, for supplying a gas under pressure, for mixing the liquid surfactant solution and the pressurized gas to form a liquid coarse dispersion of relatively large gas bubbles, and for receiving the liquid coarse dispersion to generate a liquid fine dispersion of relatively small micron-size gas bubbles. The fine dispersion generator mean generally comprises a cylindrical chamber having an inlet for admitting the liquid coarse dispersion into the chamber, and an outlet for discharging a liquid fine dispersion of relatively small micron-size gas bubbles from the chamber; a cylindrical rotor which is mounted within the chamber and has an outer side surface which is provided with means for imparting axial motion components in opposite directions to various portions of the liquid dispersion adjacent to rotor; and a plurality of baffles located between the rotor outer side surface and the chamber inner side wall surface which are spaced apart around the rotor and where each baffle has an inner longitudinal edge which faces the rotor outer side surface and is separated therefrom by a first gap within which the large gas bubbles are sheared into small micron-size gas bubbles.