Patent ID: 7802775

Claim:
A method of mixing a fluid and a gas, the method comprising: injecting the gas into the fluid; feeding a flow of the fluid and gas into an upper part of a vertically oriented mixing chamber having mainly a cylindrical shape with smooth interior walls, wherein the fluid and gas are fed into the mixing chamber at a pressure of 1.5-10 bar by means of an inlet nozzle in such a way that the fluid and gas flow into the mixing chamber at high velocity and fill the mixing chamber, wherein the flow of the fluid and gas into the mixing chamber forms a turbulent gas/fluid phase with internal recirculation in the upper part of the mixing chamber and mainly a fluid phase in a lower part of the mixing chamber; maintaining the pressure in the mixing chamber at 1.35-9 bar to avoid essential pressure loss in the mixing chamber; and drawing off the fluid phase with dissolved gas from an outlet pipe arranged at a bottom of the mixing chamber, wherein the outlet pipe has an outlet nozzle and at least the outlet nozzle is submerged in fluid where the pressure is released.