Mixing device for mixing a spray from an injector into a gas and system comprising same

Patent metadata

Field	Value
Publication number	US-2021039056-A1
Application number	US-201916964923-A
Country	US
Kind code	A1
Filing date	Jan 25, 2019
Priority date	Jan 26, 2018
Publication date	Feb 11, 2021
Grant date	—

Abstract

A mixing device includes a mixing cavity having a partially open wall and a closed wall. In certain examples, the partially open wall and the closed wall are two separately formed pieces. A downstream side of the mixing device is shaped so as to define a helicoidal groove for circumferentially guiding gas from an outlet opening of the mixing cavity in a downstream direction. An injector sprays reactant into the mixing cavity.

First claim

1 - 20 . (canceled)

21 . A mixing device for mixing a spray from an injector into a gas flowing through a substantially tubular chamber from an upstream side to a downstream side, said mixing device comprising:
a partially open wall on a side upstream of said spray; and a closed wall on a side downstream of said spray; said closed wall and said partially open wall together forming a surface closed onto itself defining a mixing cavity, said mixing cavity comprising:
a spray inlet opening for receiving a conical spray from said injector; and
an outlet opening in a plane intersecting an axis of said injector;
a downstream side of said mixing device being shaped so as to define a helicoidal groove for circumferentially guiding said gas from said outlet opening in a downstream direction.

22 . The mixing device according to claim 21 , wherein said partially open wall is permeable to gas.

23 . The mixing device according to claim 21 , wherein said partially open wall comprises a wall with perforations.

24 . The mixing device according to claim 23 , wherein at least some of said perforations are provided with louvers.

25 . The mixing device according to claim 21 , wherein said partially open wall at least partially follows a conical surface parallel with the outer boundary of said spray.

26 . The mixing device according to claim 21 , wherein said outlet opening is substantially perpendicular to an injection axis of said injector.

27 . The mixing device according to claim 21 , further comprising a spray disperser arranged at said outlet opening.

28 . The mixing device according to claim 27 , wherein said spray disperser is a mesh.

29 . The mixing device according to claim 21 , wherein said closed wall bends or tapers towards the upstream side in a direction approaching said spray inlet opening.

30 . The mixing device according to claim 21 , wherein said mixing cavity is shaped as a cylindrical or frustoconical pipe with perforations in at least the partially open wall or as a cylindrically or frustoconically shaped mesh surface.

31 . The mixing device according to claim 21 , wherein the partially open wall and the closed wall are two separately formed pieces, distinct from any wall of the substantially tubular chamber and joined together so as to form the surface closed onto itself defining the mixing cavity.

32 . The mixing device according to claim 21 , wherein the closed wall is an integral part of a larger piece that also presents a baffle portion on either side of the mixing cavity, and a skirt portion arranged directly upstream of a space below the outlet opening.

33 . A system for treating exhaust gas, the system comprising:
a substantially tubular chamber receiving a flow of exhaust gas to be treated; a mixing device for mixing a spray from an injector into a gas flowing through a substantially tubular chamber from an upstream side to a downstream side, the mixing device including a partially open wall on a side upstream of said spray and a closed wall on a side downstream of said spray, the partially open wall and the closed wall being two separately formed pieces, distinct from any wall of the substantially tubular chamber and joined together so as to form a surface closed onto itself to define a mixing cavity, the mixing cavity including a spray inlet opening for receiving a conical spray from said injector and an outlet opening in a plane intersecting an axis of said injector; and an injector mounting location aligned with the spray inlet opening.

34 . The system according to claim 33 , wherein an axis of the injector mounting location does not intersect with a longitudinal axis of the substantially tubular chamber.

35 . The system according to claim 33 , wherein the mixing device is arranged so as to substantially block any flows of gas from the upstream side to the downstream side other than flows entering said mixing device through the partially open wall and leaving the mixing device through the outlet opening.

36 . The system according to claim 33 , further comprising a swirl baffle downstream of said mixing device, wherein a part of said closed wall that is further removed from a longitudinal axis of said substantially tubular chamber is at a greater distance from the swirl baffle than a part of the closed wall that is closer to the longitudinal axis of the substantially tubular chamber.

37 . The system according to claim 33 , further comprising a substantially planar swirl plate downstream of the mixing device, the substantially planar swirl plate having an annular inlet zone.

38 . The system according to claim 37 , wherein the mixing device is shaped so as to open up a helicoidal space between said mixing device and the substantially planar swirl plate, the helicoidal space serving as a flow channel from said outlet opening to the annular inlet zone.

39 . An aftertreatment device comprising:
(a) a conduit defining a main body having a longitudinal axis and a transverse cross-sectional area; (b) a swirl baffle disposed within the main body; and (c) a mixing device disposed within the main body upstream of the swirl baffle, the mixing device extending across the transverse cross-sectional area of the main body, the mixing device including an at least partially open wall and a closed wall downstream of the at least partially open wall, the closed wall and the at least partially open wall together defining a mixing cavity leading from a first region upstream of the mixing device to a second region that is downstream of the mixing device and upstream of the swirl baffle, the mixing cavity extending at an angle relative to the longitudinal axis of the main body, the mixing device being shaped so that a peripheral zone of the second region is broader than a central zone of the second region.

40 . The aftertreatment device of claim 39 , further comprising an injector mounting location configured to orient an injector mounted thereat to spray into the mixing cavity.

Assignees

• Donaldson Co Inc

Inventors

• De Rudder Korneel
• Schellens Bart
• Chauvin Corine
• Silva Fransisco

Classifications

• B01F25/4331

  Mixers with bended, curved, coiled, wounded mixing tubes or comprising elements for bending the flow · CPC title

• B01F25/3141

  with additional mixing means other than injector mixers · CPC title

• B01F25/4521

  the components being pressed through orifices in elements, e.g. flat plates or cylinders, which obstruct the whole diameter of the tube · CPC title

• B01F2025/931

  Flow guiding elements surrounding feed openings, e.g. jet nozzles · CPC title

• B01F23/2132 Primary

  using nozzles · CPC title