Flotation unit for purifying water, such as a CFU (compact flotation unit)

A flotation unit for purifying water, such as a CFU (compact flotation unit), comprising at least a separator tank, a supply duct to a tank inlet, two or more outlets for gas, oil, and water from the separator tank, and a gas injector located in the supply duct, the gas injector comprising:

• a venturi section having an inner diameter and a cross-sectional area smaller than a cross-sectional area of the supply duct,
• an ejector arranged in the venturi section along the inner diameter and having an outer side facing an inside surface of the venturi section, an inner side facing a longitudinal center axis of the venturi section, a downstream side, and a upstream side, the ejector comprising an annular gas distribution chamber and a plurality of gas outlets arranged along a side of the ejector and connected to the gas distribution chamber, and a gas inlet for supplying gas to the gas distribution chamber,
• wherein the ejector has an outer diameter which is smaller than the inner diameter of the venturi section and the gas outlets are arranged in the downstream side of the ejector.