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.

An exhaust gas turbine (30) for expanding exhaust gas, comprising a turbine housing (33) having an inflow housing portion (35) for exhaust gas to be expanded and an outflow housing portion (36) for expanded exhaust gas, a turbine rotor (34) received by the turbine housing (33), the turbine rotor (34) being rotatable about an axis of rotation, a metering means (42) for a reducing agent or a precursor substance of a reducing agent, wherein the reducing agent or the precursor substance can be introduced into the expanded exhaust gas via the metering device (42), and with a swirl atomizer (43), rotating together with the turbine rotor (34), for the reducing agent or the precursor substance, the reducing agent or the precursor substance being atomizable in the expanded exhaust gas via the swirl atomizer (43), the swirl atomizer (43) engaging the turbine rotor (34) at a downstream, hub-side portion of the turbine rotor (34). Downstream of the turbine rotor (34) in extension of the axis of rotation of the turbine rotor (34), an impingement body (44) is arranged for the reducing agent or the precursor substance introduced into the exhaust gas and atomized, wherein a distance of the impingement body (44) from the swirl atomizer (43) corresponds to at most 7 times a diameter of the turbine rotor (34).

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.

A distribution tube for a static mixer provides efficient mixing with improved performance over a wide range of flow rates. The distribution tube is positioned near an inlet side of the static mixer. An injected fluid is introduced into the static mixer via the distribution tube, which pre-mixes the injected fluid with a main fluid prior to further mixing by mixing elements of the static mixer.

A mixer and a method therein, including feeding a rotating flow of exhaust gas in a mixing pipe towards a turning end of a mixing chamber; dosing reactant by a doser against the rotating flow around a centreline of the mixing pipe; maintaining a guide around the doser such that a front face of the guide faces the rotating flow, and the guide defines a central opening surrounding the doser; guiding a side flow out of the rotating flow to a carrier flow around the doser via the central opening; and inhibiting by the guide turbulence from being transferred from the side flow to the carrier flow.

A flow-through cavitation device having an elongated housing with an inlet and an outlet. An inner annular body and an outer annular body are concentrically and nestingly disposed in the elongated housing. The outer annular body is fixed relative to the housing and the inner annular body is rotatable about a longitudinal axis of the housing. Each annular body has a plurality of channels that pass therethrough. Rotation of the inner body relative to the outer body provides for selective alignment or misalignment of the plurality of channels to control fluid flow from the inlet to the outlet. The device may have a plurality of pairs of inner and outer annular bodies as described.

Apparatus for introducing a gas into a main medium, comprising: a main conduit for guiding the main medium, a multitude of injection lines for guiding the gas, wherein each of the injection lines has a respective end section with a respective outlet opening situated within the main conduit, and wherein the end sections are oriented essentially parallel to each other and to the main conduit. With the apparatus a gas can be introduced in particular into waste water for obtaining a biologically activated sludge. Thereby, interaction between the gas and the waste water can be particularly pronounced due to a particularly large liquid-gas-interface caused by particularly extensive turbulences. Further, shear stress acting on particles in the activated sludge can be advantageously low, thus avoiding damage of the biological particles.

A swirl mixer for mixing a reducing agent with exhaust gas in a selective catalytic reduction (SCR) aftertreatment system is described. The swirl mixer may comprise a base permitting a flow of the reducing agent and the exhaust gas therethrough, and three arrays of fins projecting from the base in a direction of flow of the exhaust gas. The three arrays of fins may be arranged in a triangular configuration about a center of the mixer to induce a swirl motion to the reducing agent and the exhaust gas flowing through the mixer. The fins in each of the arrays may be oriented in a common direction that is rotated by about 60° from the common direction of the fins in an adjacent array.

A dual mixer for mixing a reducing agent with exhaust gas in a mixing section of a selective catalytic reduction (SCR) aftertreatment system is disclosed. The dual mixer may comprise a first mixer including a grid and a plurality of trapezoidal fins projecting from the grid in a direction of flow of the exhaust gas. The dual mixer may further comprise a swirl mixer positioned downstream of the first mixer and separated therefrom by a distance. The swirl mixer may include a base and three arrays of swirl fins projecting from the base in the direction of flow of the exhaust gas. The swirl fins in each of the arrays may be oriented in a common direction that is rotated by about 60° from the common direction of the swirl fins in an adjacent array.

An improved thermal fogging device includes an extended heat transfer surface located within the aerosolization chamber that increases the mixing of the liquid chemical particles and the hot gases in the aerosol to improve aerosolization. The extended heat transfer surface also helps to increase the heat transfer to the forming aerosol in the aerosolization chamber.