Chamber mixer for an exhaust after-treatment system of a motor vehicle

Chamber mixer (10) for an exhaust after-treatment system of a motor vehicle, wherein a first fluid (58) can flow through the internal volume (14), which is delimited by a housing (12), from an inlet opening (18) arranged at one end of the internal volume (14) in the housing (12) to an outlet opening (20) arranged at the other end of the internal volume (14) in the housing (12) in a through-flow direction (22), and at least a second housing side (80) of the housing (12) is of double-walled design with an outer wall (24) and an inner wall (26), which divides the internal volume (14) into an inner chamber (28) and an outer chamber (30) located between the inner wall (26) and the outer wall (24), and the first fluid (58) flowing in through the inlet opening (18) can be divided into a main flow (54) flowing through the inner chamber (28) and an auxiliary flow (56) flowing through the outer chamber (30), and a flow device (32) is provided, by means of which the main flow (54) can be subjected to a double swirl (70) in the through-flow direction (22) and with a fluid introduction device (34) with an introduction end (36), which is arranged in the outer chamber (30) and via which a second fluid (38) can be injected into the inner chamber (28) through an introduction opening (40) in the inner wall (26), and a merging device (42) is provided downstream in the direction of flow (22), through which the main flow (54) and the auxiliary flow (56) can be guided into one another.