Abstract: The invention relates to a mixing device for the homogenization of temperatures and/or concentrations in a fluid flow, having a hollow element, for conducting the fluid flow, which hollow element has: (a) a first insert positioned within the hollow element and defining an excentric passage; (b) a second insert positioned within the hollow element upstream of the first insert, wherein the second insert has a central opening; (c) a third insert positioned in the hollow element downstream of the first insert and the second insert, which third insert has at least two openings, which are evenly distributed along a concentric circle within said third insert; and (d) a fourth insert positioned in the hollow element between the first insert and the third insert, wherein the fourth insert has at least two radially extending first deflectors.