Abstract: Foam producing equipment in which a container interior is sub-divided by a concentric array of cylindrical shells into radially spaced concentric chambers. A relatively small amount of a foamable liquid solution is held in the lower part of the container, and, above the liquid level, the shells are selectively perforated. A compressed gas is admitted to an outermost concentric chamber and agitates the liquid solution therein to form a foam which rises and then in a generally radial motion moves progressively through the perforate wall portions of the concentric shells to a foam outlet associated with a central, innermost concentric chamber. A staged extraction of liquid, with foam compaction, occurs as the foam is forced through successive perforate shell portions, with separated liquid utilizing imperforate wall portions of the shells to drain back into the supply of the liquid solution.