Spiral outlet channel

It describes a system for treating exhaust gases from an engine. The system includes that exhaust gases are led from the engine through a spiral exhaust passage to the atmosphere, the plant comprises an exhaust duct that receives an exhaust stream, in which a liquid reducing agent has been injected, wherein the spiral outlet channel comprises a plurality of outlet channels, which in the exhaust gas stream parts separate smaller currents, with the smaller streams are introduced again in a common channel and together forming a single exhaust gas stream and wherein the alignment of the plurality of exhaust ports causes the single exhaust gas stream to have a spiral flow pattern.