- The study is motivated by development of a low cost technology for multipurpose water and surface treatment in chemical industry and beyond, using microbubbles. Novel scheme of liquid-gas interaction within specially designed bubble generator was tested and its efficiency for production of microbubbles with size distribution in micron range is confirmed. The basic element of the device is vortex chamber with water supply through tangential ducts, while the gas (air) is introduced in a high turbulent swirling flow of water in radial direction through the orifice in the gas supply duct, located on the chamber axis. Bubble diameters were measured by TSI PDPA/LDV system within transparent section attached to the microbubbles generator. The results indicate that about 90% of generated bubbles are in the size range between 1 and 35 µm with calculated mean diameters D10 ~ 8 µm and D32 ~ 20 µm. The bubble velocities in the pipe flow were measured as well; it was found that certain number of bubbles after exit from the vortex chamber is involved in circulation flow with axial velocity opposite to the main stream. Effect of the output pressure on the bubble size distribution was studied also. Slight tendency to increase of the D10, D32 parameter values with the pressure growth was revealed; the measurements were made at fixed values of the liquid flow rate and pressure drop both on the liquid and gas supply lines.