Mixing device carbonator appliance comprising a carbonator and method of producing a carbonated beverage

A carbonator (40) for mixing a non-carbonated beverage with CO2 gas for producing carbonated beverage, the carbonator (40) comprising a mixing device (2) for a beverage;

• CO2 gas for producing carbonated beverage;
• and a CO2 inlet arrangement (42) for admitting the CO2 gas into the beverage,
• wherein the mixing device (2) comprises a mixing channel (4), an inlet (6) to the mixing channel (4) and an outlet (8) for carbonated beverage from the mixing channel (4), wherein the mixing channel (4) extends in a main direction (10), along which main direction (10) the beverage is adapted to flow, wherein the mixing channel (4) comprises first channel sections (16) and second channel sections (18) along the main direction (10), characterized in that the mixing channel (4) has an elongated cross section seen in a direction perpendicular to the main direction (10), wherein at least a first delimiting surface (22) of the mixing channel (4) is provided with protrusions (20) extending at least partially along the first delimiting surface (22) in a first direction across the mixing channel (4) and protruding towards a second delimiting surface (24) of the mixing channel (4) to form the second channel sections (18), wherein cross sections of the first delimiting surface (22) taken perpendicular to the main direction at the first channel sections (16) and at the second channel sections (18) are circular, wherein the second channel sections (18) are narrower than the first channel sections (16), wherein the first delimiting surface (22) and the protrusions (20) are separated from the second delimiting surface (24), wherein cross sections of first channel sections (16) taken perpendicular to the main direction (10) are ring shaped and cross sections of the second channel section (18) taken perpendicular to the main direction (10) are ring shaped,
• wherein the CO2 inlet arrangement (42) comprises an admixing passage (44) and a CO2 inlet nozzle (46), which admixing passage (44) is connected to a beverage source and the inlet of the mixing channel (4), wherein the CO2 inlet nozzle (46) is connected to the admixing passage (44) such that in use the beverage and the CO2 gas are mixed in two steps, a first mixing step in the admixing passage (44) and a second mixing step in the mixing channel (4), and wherein the admixing passage (44) is connected to the inlet (6) to the mixing channel (4).