An exhaust mixing device for mixing an exhaust produced by an engine with a reagent exhaust treatment fluid that is dosed into the exhaust from a dosing module. The exhaust mixing device includes a decomposition tube having a first end and a second end. The first end of the decomposition tube is configured to receive the exhaust and the reagent exhaust treatment fluid. A flow reversing device is positioned at the second end of the decomposition tube. The flow reversing device includes a plurality of deflecting members that intermix the exhaust and reagent exhaust treatment fluid, and direct the exhaust and reagent exhaust treatment fluid in predetermined directions, wherein the flow reversing device reverses a flow direction of the exhaust back towards the first end of the decomposition tube.