Patent GB-654323-A (GB)
Title: Improvements in and relating to the production of bubbles and drops
Inventor: PATTLE RICHARD ERIC
IPC: B01F3/04
Filed: 1948-10-14
Abstract: A method of producing small drops of a liquid, of substantially uniform size, in a liquid medium from a stream of liquid which is passed through a capillary tube and allowed to escape through an orifice immersed in the liquid medium, wherein said liquid medium contains a surface active agent and the tube has a narrow elongated slit extending from the orifice or has a suitable aperture or slit or the like in addition to the said orifice, to allow the liquid medium to gain access to the liquid stream prior to issuing from the orifice, or an obstruction is placed in the path of the drop being formed, any of the foregoing arrangements being such that each drop is formed with an elongated neck and the p  liquid medium is enabled to detach the drop from the capillary tube by surface tension forces. As described, the capillary tube may be of steel or glass 3 cm. long having a bore of 200 m  bent to form a P so that its orifice is about 200 m  from the stem of the tube or may be a steel tube 3 cm. long having a bore of 200 m , a slit in the wall of 50 m  width extending longitudinally from the orifice for a distance of 500 m , or a hole 170 m  diameter being drilled in the wall within 1 mm. of the orifice. The surface active agent may be soap or a dilute aqueous solution of an organic substance containing the polar groups OH or -COOH, values being given for the minimum concentrations of the following substances which may be used for this purpose, acetic acid, methyl alcohol, ethyl alcohol, capryl alcohol and sodium oleate.  It is stated that by forming drops of one liquid in a hot portion of another liquid and allowing said drops to solidify in a cooler portion of the latter liquid, large numbers of solid spheres of uniform size may be obtained.  The steel tubes are heated to give them an oxidized surface to enable the liquid in which they are immersed to wet them.ALSO:A method of producing small bubbles of gas (or small drops of a liquid), of substantially uniform size, in a liquid medium from a stream of gas (or liquid) which is passed through a capillary tube and allowed to escape through an orifice immersed in the liquid medium, wherein said liquid medium contains a surface active agent and the tube has a narrow elongated slit extending from the orifice or has a suitable aperture or slit or the like in addition to the said orifice, to allow the liquid medium to gain access to the gas (or liquid), stream prior to issuing from the orifice, or an obstruction is placed in the path of the bubble (or drop) being formed, any of the foregoing arrangements being such that each bubble (or drop) is formed with an elongated neck which becomes unstable as the pressure within the bubble falls and liquid medium is enabled to detach the bubble (or drop), from the capillary tube by surface tension forces.  As described the capillary tube may be of steel or glass 3 cm. long having a bore of 200m  bent to form a P so that its orifice is about 200m  from the stem of the tube or may be a steel tube 3 cm. long having a bore of 200m , a slit in the wall of 50m  width extending longitudinally from the orifice for a distance of 500m , or a hole 170m  diameter being drilled in the wall within 1 mm. of the orifice.  The surface active agent may be soap or a dilute aqueous solution of an organic substance containing the polar groups OH or -COOH, values being given for the minimum concentrations of the following substances which may be used for this purpose, acetic acid methyl alcohol, ethyl alcohol, capryl alcohol and sodium oleate.  It is stated that by forming drops of one liquid in a hot portion of another liquid and allowing said drops to solidify in a cooler portion of the latter liquid, large numbers of solid spheres of uniform size may be obtained.  The steel tubes are heated to give them an oxidized surface to enable the liquid in which they are immersed to wet them.