Abstract: A method and apparatus for dissolving and mixing a gas and a liquid wherein an injection portion for injecting a liquid at a flow rate in the range from approximately 5 m/s to approximately 15 m/s in a horizontal direction is provided at an upper part of a mixing container filled with a gas; a restrictor for maintaining a pressurized state in the mixing container is provided downstream of the mixing container; and a liquid is injected into the mixing container from the injection portion to cause a reaction or dissolution between the gas in the mixing container and the injected liquid in the pressurized state and to cause a liquid including the gas dissolved therein to flow from a lower part of the mixing container. The gas is supplied upstream of the injection.

Abstract: An apparatus for mixing a gas with a liquid and for dissolving the gas in the liquid comprises a throttled section (12) formed in a fluid flow passage, a gas inlet (18) provided slightly downstream of the throttled section (12), a widened section (16) which is continuous with the throttled section (12), a mixing section (20) provided downstream of the widened section (16), for mixing the gas introduced from the gas inlet (18) with the liquid in the fluid flow passage, and a nozzle section (24) provided on the outlet of the mixing section (20) for outputting the liquid with the gas dissolved therein. The gas is dissolved in the liquid in the mixing section by pressurizing the liquid in the mixing section. The apparatus is useful for dissolving ozone into a liquid, for dispersing bubbles in a liquid and for floating small particles in a liquid.