A multi-stage mixer includes a multi-stage mixer inlet, a multi-stage mixer outlet, a first flow device, and a second flow device. The multi-stage mixer inlet is configured to receive exhaust gas. The multi-stage mixer outlet is configured to provide the exhaust gas to a catalyst. The first flow device is configured to receive the exhaust gas from the multi-stage mixer inlet and to receive reductant such that the reductant is partially mixed with the exhaust gas within the first flow device. The first flow device includes a plurality of main vanes and a plurality of main vane apertures. The plurality of main vane apertures is interspaced between the plurality of main vanes. The plurality of main vane apertures is configured to receive the exhaust gas and to cooperate with the plurality of main vanes to provide the exhaust gas from the first flow device with a swirl flow.

A spray/gas mixer includes a main body having a circumferential wall defining an inlet opening at one end and an outlet opening at another end; a divider baffle within the main body; a swirl duct having a first end adjacent to the wall and a second end extending to the divider baffle; an injector orifice at the first end of the swirl duct; a swirl promoting means; and a restrictor. The swirl promoting means is arranged between the divider baffle and the restrictor. Gas passing through the swirl promoting means is swirled around the first longitudinal axis (A) before passing through the restrictor. The restrictor is disposed between the swirl promoting means and the second end, forcing gas reaching it from an upstream side away from a peripheral region of the interior towards a center axis of the main body.

A mixer arrangement for an exhaust gas system, having an inlet opening through which an exhaust gas mass flow (A) can be guided, and a mixer for swirling the exhaust gas, which has at least one inflow opening that is fluidically connected to the inlet opening, wherein at least one first portion (A1) of the exhaust gas mass flow (A) can be guided through the mixer via the at least one inflow opening, an injection device by means of which an additive can be injected, and a bypass having at least one throughflow opening which is fluidically connected to the inlet opening and through which a second portion (A2) of the exhaust gas mass flow (A) can be guided past the mixer, there being provided at least one regulating body by means of which a flow cross-section Q in the mixer arrangement can be varied such that a ratio V with (formula I) can be varied.

An exhaust aftertreatment system for an internal combustion engine includes an outer casing defining an exhaust flow path for exhaust gases from the internal combustion engine, a selective catalytic reduction unit provided in the exhaust flow path for reducing nitrogen oxides, a urea dosing device for adding urea to the exhaust flow upstream of the selective catalytic reduction unit, and a rotatable mixer device for mixing the urea with exhaust gases upstream of the selective catalytic reduction unit. The exhaust aftertreatment system further comprises an air inlet valve provided upstream of the mixer device for introducing air into the exhaust flow path, and an electric motor arranged for rotating the mixer device to create a suction of air into the exhaust flow path via the air inlet valve.

An aftertreatment system comprises: a housing, a SCR system disposed in the housing. A mixer is disposed upstream of the SCR system and includes: a hub, a tubular member disposed circumferentially around the hub and defining a reductant entry port, and plurality of vanes extending from the hub to the tubular member such that openings are defined between adjacent vanes. The plurality of vanes swirl the exhaust gas in a circumferential direction. A reductant injector is disposed on the housing upstream of the SCR system along a transverse axis and configured to insert a reductant into the exhaust gas flowing through the housing through the reductant entry port. The reductant is inserted at a non-zero angle with respect to the transverse axis opposite the circumferential direction to achieve virtual interception. A mixer central axis is radially offset with respect to a housing central axis of the housing.

The description relates to methods and apparatus that enable the efficient introduction of gases like air, oxygen and ozone into aqueous liquids. Gases are introduced into liquids for making that gas chemically or biologically available at a minimum energy expenditure. Impinging jets of liquid are directed into a pressurized saturation vessel having a gas-filled headspace and a saturation zone below the surface of the liquid at a velocity sufficient to create a turbulent impact and plunge zone. The resulting turbulence and mixing of gas and liquid in that zone under pressure, causes the gas to be driven into the liquid in the vessel and breaks up the gas and the liquid into a churning flow and creates a large number of bubbles. The resulting gas-enriched liquid is discharged from the vessel at an outlet to ensure a minimum of bubbles in the gas-enriched liquid.

The subject matter of this specification can be embodied in, among other things, a gas mixer that includes a convergent-divergent nozzle comprising a convergent portion and a divergent portion and defining a first gas flow path, an air housing comprising an air inlet configured to supply air to the first gas flow path upstream of the convergent-divergent nozzle, a gas housing defining a second gas flow path and including a first gas inlet configured to receive a secondary gas and allow the secondary gas into a second gas flow path, and a gas nozzle positioned parallel to and centrally within the first gas flow path in a convergent portion of the convergent-divergent nozzle, the gas nozzle configured to supply the secondary gas to the first gas flow path upstream of the divergent portion.

An engine system includes an internal combustion engine having an exhaust system with an SCR aftertreatment mechanism and a urea injector upstream the aftertreatment mechanism. A mixing mechanism is positioned fluidly between the urea injector and the aftertreatment mechanism and includes a turbulator and a swirler structured to increase mixing of the urea and exhaust gases. Related methodology is also disclosed.

An exhaust treatment system for a work vehicle includes a selective catalytic reduction (SCR) system having an SCR outlet for expelling treated exhaust flow therefrom, a flow conduit in fluid communication with the outlet, an exhaust sensor positioned within the flow conduit downstream of the outlet, and a flow mixer positioned upstream of the exhaust sensor. The flow mixer has an end wall defining sector openings circumferentially extending between first and second sector sides and radially between radially inner and outer sector ends. Moreover, the flow mixer has swirler vanes, where each of the swirler vanes extends circumferentially from the first sector side of a respective one of the sector openings and radially between radially inner and outer vane ends. Particularly, the radially outer vane end of each of the swirler vanes is spaced apart from the radially outer sector end of the respective one of the sector openings.

An injection and mixing device comprises a casing having an exhaust inlet and an exhaust outlet, the casing internally defining a passage for exhaust gases from the exhaust inlet to the exhaust outlet. The exhaust inlet opens into an inlet region of the passage. The injection and mixing device further includes an injector of a liquid comprising a nitrogen oxide reducing agent or a precursor of such a reducing agent. A deflector is housed within the casing and defines in the passage a first passage connecting the inlet region to the exhaust outlet, in which the exhaust gases flow at a first average velocity, and a second passage connecting the inlet region to the exhaust outlet, in which the exhaust gases flow at a second average velocity lower than the first average velocity, The injector injects liquid into the second passage.