Patent ID: 8231263
Filing Date: 2012-07-31
Classification: B01F

Abstract:
1. A process for making a foam having a controlled size distribution of gas bubbles in a liquid matrix, which comprises: passing a flow of a gas to and through a porous metal membrane configured in the shape of a cylinder of uniform diameter and having a controlled pore size and a controlled pore distance that is at least 3 to 5 times the average pore diameter to produce a substantially uniform size distribution of gas bubbles; passing a flow of liquid matrix past the porous metal membrane to collect, accumulate, detach and entrain the gas bubbles in the liquid matrix to form a foam having gas bubbles of generally uniform size and a substantially uniform gas bubble size distribution; wherein the liquid flow passes through a gap of constant width between the porous metal membrane and a housing wall surface to carry the bubbles away, with the gap having a width in the range of 0.1 to 10 millimeters; and rotating the cylinder, the wall surface or both in order to detach the gas bubbles from the porous metal membrane surface and to entrain the gas bubbles in the liquid matrix.