Patent ID: 9670811
Date: 2017-06-06
CPC Classifications: B01F,F01N,Y02T

Claim:
1. A dosing and mixing unit comprising: a swirl housing having a curved side wall that defines a curved flow-deflection surface within the swirl housing, the dosing and mixing unit also including an inlet pipe that projects outwardly from the swirl housing and an outlet pipe that projects outwardly from the swirl housing, the inlet pipe having a free end adapted for connection to a pipe, wherein the swirl housing defines an open space that extends from the inlet pipe to the curved side wall such that flow from the inlet pipe impinges directly against the curved side wall; a mixing tube having a constant diameter along its length, the mixing tube including a plurality of apertures; the curved side wall of the swirl housing curving circumferentially along and opposing an outer surface of the mixing tube, the inlet pipe being oriented to direct exhaust flow toward the curved side wall such that the inlet pipe and the curved side wall cooperate to define a swirl structure for causing exhaust flow to swirl outside of the mixing tube in one rotational direction along a flow path that extends at least 270 degrees around a central axis of the mixing tube, wherein the exhaust enters an interior of the mixing tube through the apertures as the exhaust swirls along the flow path, and wherein the exhaust entering the interior of the mixing tube through the apertures swirls around the central axis within the interior of the mixing tube; a source of aqueous urea; and a doser coupled to the source of aqueous urea and disposed adjacent an end of the mixing tube, the doser being configured to dispense aqueous urea from the source of aqueous urea into the interior of the mixing tube for mixing with the swirling exhaust within the interior of the mixing tube.