Compact evaporation and mixing device

A liquid evaporation and gas mixing device for an exhaust gas after-treatment system, the device is for mixing an exhaust gas stream from the exhaust gas after-treatment system with an evaporated liquid reductant, the device comprising a housing that defines a longitudinal axis and having an upstream inlet receiving the exhaust gas stream and a downstream outlet distributing the mixed exhaust gas stream and evaporated reductant, and which comprises:

• a) a first mixing chamber adapted to swirl the exhaust gas stream inside the chamber and having at least one inlet for receiving the exhaust gas stream and at least one outlet, wherein
• the first mixing chamber defines a longitudinal axis,
• b) a second mixing chamber adapted to swirl the exhaust gas stream inside the chamber and having at least one inlet for receiving the exhaust gas stream and at least one outlet,
• wherein the second mixing chamber defines a longitudinal axis,
• c) a dosing module for spraying a liquid reductant into the first chamber or the second chamber or both first and second chamber for evaporation and mixing with the exhaust gas stream,
• d) a third mixing chamber in fluid tight communication with the at least one outlet of the first mixing chamber and in fluid tight communication with the at least one outlet of the second mixing chamber and having at least one outlet for distribution of the exhaust gas stream mixed with the evaporated reductant, wherein at least one outlet for distribution of the exhaust gas stream mixed with the evaporated reductant of the third mixing chamber is essentially perpendicular to the longitudinal axis of the first mixing chamber and essentially perpendicular to the longitudinal axis of the second mixing chamber,
• e) a baffle located downstream from the upstream inlet and in fluid tight communication with the at least one outlet of the third mixing chamber,
• wherein the third mixing chamber is located between the first and second mixing chambers defining a longitudinal axis perpendicular to the longitudinal axis of the housing and wherein the third mixing chamber expels the exhaust gas stream mixed with the evaporated reductant along the longitudinal axis of the housing.