Abstract: A method and an apparatus for generating gas bubbles, which can generate a large amount of micro gas bubbles having diameters of less than 15 ?m, specifically less than 10 ?m, in a liquid. The apparatus comprises a tube 2 having a closed end 14 at one end and an open end 15 at the other end, and a rotating bladed wheel 3 installed in the tube 2 and rotating coaxially or substantially coaxially with the tube 2. The rotating bladed wheel 3 has one or more blades 4. The face of each blade 4 is substantially parallel to the axis of a rotating shaft 5 of the rotating bladed wheel 3. Ventilation resistance between the interior of the tube 2 on the side near the closed end 14 and the outside gas is equal to or larger than that of a ventilation port 7 having an inner diameter of 0.36 time an average width d of the blades and a length of 3 mm. At least the open end 15 of the tube 2 and the rotating bladed wheel 3 are immersed in a liquid 20 and the rotating bladed wheel 3 is rotated at a peripheral speed of 5.

Abstract: A method and an apparatus for generating gas bubbles, which can generate a large amount of micro gas bubbles having diameters of less than 15 ?m, specifically less than 10 ?m, in a liquid. The apparatus comprises a tube 2 having a closed end 14 at one end and an open end 15 at the other end, and a rotating bladed wheel 3 installed in the tube 2 and rotating coaxially or substantially coaxially with the tube 2. The rotating bladed wheel 3 has one or more blades 4. The face of each blade 4 is substantially parallel to the axis of a rotating shaft 5 of the rotating bladed wheel 3. Ventilation resistance between the interior of the tube 2 on the side near the closed end 14 and the outside gas is equal to or larger than that of a ventilation port 7 having an inner diameter of 0.36 time an average width d of the blades and a length of 3 mm. At least the open end 15 of the tube 2 and the rotating bladed wheel 3 are immersed in a liquid 20 and the rotating bladed wheel 3 is rotated at a peripheral speed of 5.