Method and apparatus for producing foam

A foam generator for producing foam from a foamable medium and a gaseous medium comprising:

• a mixing chamber (3), a first transfer device (23) coupled to the mixing chamber for selectively transporting the gaseous medium to the mixing chamber, a second transfer device (21) coupled to the mixing chamber for selectively transporting the formable medium to the mixing chamber, a gas inlet chamber (5) coupled to the mixing chamber (3) and the first transfer device for allowing gas to pass from the first transfer device to the mixing chamber, a porous partition wall (7) having pores with a substantially uniform pore size coupled to the mixing chamber and the gas inlet chamber, and a differential pressure setter (27) coupled to the first and second transfer devices for controlling the first and second transfer devices and for ensuring the passage of the gas through the pores of the partition wall (7) into the mixing chamber (3), wherein the differential pressure setter maintains a predetermined pressure gradient (.DELTA.p) between the gas inlet chamber (5) and mixing chamber (3) during foam production, wherein the mixing chamber (3) is surrounded by the porous partition wall (7), wherein the inlet and outlet (15, 16) of the foam-forming medium are arranged axially at opposed end faces of the mixing chamber and, wherein the flow cross-section of the inlet (15) through the mixing chamber (3) to the outlet (16) is substantially constant.