An improved mixing apparatus for mixing a liquid within a liquid body is provided. Generally, the improved mixing apparatus may comprise: a supporting element (1) with a partly conical volute with an upper corrugated free edge; a top-mounted power drive (2); and an impeller (4) mounted on said shaft (3) for rotation therewith.

A device and method for injection of oxygen-rich gas into a body of liquid with oxygen recycling are disclosed. The device comprises a rotary hollow shaft vertically passing through a float partially immersed in the liquid, an impeller attached to the lower end of the rotary hollow shaft, a columnar structure, surrounding the rotary hollow shaft, mounted on the bottom side of the float and vertically extending into the liquid, a gas diffusion chamber formed by the columnar structure, the float and the liquid surface under the float, and a gas injection conduit passing through the float for delivering the oxygen gas into the gas diffusion chamber, wherein a vacuum is generated in the body of the liquid around the impeller when the impeller is driven to rotate, so that the oxygen-rich gas in the gas diffusion chamber is sucked into the body of the liquid and mixed therein.

An agitator includes a central shaft, a radially spaced array of vanes and a shroud encircling the central shaft so as to intersect the vanes perpendicular to the vanes' depth and along their length, thus defining an inner passageway between the shroud and the central shaft and an outer passageway between the vanes, radially extending outwardly of the shroud.

Disclosed herein are a refrigerator and a control method of the same. The refrigerator includes a purified water pump which increases a pressure of water, a carbon dioxide regulator which decreases a pressure of carbon dioxide, a mixing pipe which mixes water which introduced from the purified water pump and carbon dioxide which introduced from the carbon dioxide regulator, and produces carbonated water, a user interface which receives a production condition of carbonated water from a user, and a controller which controls the purified water pump and the carbon dioxide regulator such that the pressure of the water and the pressure of the carbon dioxide reach a target pressure corresponding to the input production condition.

A stirrer includes a stirring shaft; a plurality of mixing wings extending from the lower end of the stirring shaft and spaced from each other around the stirring shaft; and a conical hub connecting the lower ends of the mixing wings.

Disclosed is a method for managing the operation of an apparatus for injecting oxygen into a purification basin. The oxygen notably being used by the biomass present in the purification basin to consume the pollution present in an effluent feedstock contained in the basin. The method comprises varying a rotational speed of the shaft by using a frequency variator, wherein an applied variation in speed is between plus 15% and minus 15% of the nominal speed of the shaft.