Device for agitating a liquid in a reactor and for injecting a gas into this liquid

A device useful for agitating a liquid in a container and for injecting a gas into this liquid, comprising:

• a drive device arranged above the container, the drive device provided with a vertical output shaft having a lower end, the drive device including at the output shaft lower end at least one axial-flow mobile assembly to be immersed in the liquid;
• a cylinder having an upper end and a lower end, the cylinder upper end linked to the drive device in a leakproof manner;
• wherein the output shaft of the drive device includes an autosuction turbine immersed in the container and drivable by the output shaft, the output shaft being enveloped coaxially by the cylinder and delimiting an annular gap between the output shaft and the cylinder, the lower end of the cylinder opening out into the turbine;
• wherein the upper end of the cylinder includes an aperture for injecting a gas into the annular gap delimited by the shaft and the cylinder;
• wherein the turbine comprises two superposed discs and a set of radial vanes arranged between the discs and fixed to them, one of the two superposed discs being an upper disc including a central hole into which penetrates the lower end of the cylinder, the lower end of the cylinder together with the edge of the said hole delimiting an at least partially annular space through which liquid can be sucked into the turbine.