Mixer assembly and tail gas aftertreatment device

Abstract

A mixer assembly includes a first baffle, a second baffle, an annular wall, and a deflector. The mixer assembly includes a cavity located between the first baffle and the second baffle. The flow guide plates are located in the cavity and comprise the first flow guide plate and the second flow guide plate. The mixer assembly includes an airflow diverging port located between the first deflector and the second deflector. The mixer assembly comprises a mixing space located between the annular wall and the flow guide plate, an airflow inlet communicated with the mixing space and an air outlet cavity located on the inner side of the flow guide plate. And the air flow forking opening is communicated with the mixing space and the air outlet cavity. According to the arrangement, a part of air flow in the mixing space can flow into the air outlet cavity from the air flow forking opening, so that the uniformity of air flow distribution is improved. The invention further discloses a tail gas aftertreatment device with the mixer assembly.

Description

Technical Field

[0001] The invention relates to a mixer component and an exhaust gas after-treatment device, belonging to the technical field of engine exhaust gas after-treatment. Background Art

[0002] The exhaust gas aftertreatment device in the related art generally includes a mixer assembly, which is used to improve the mixing of the exhaust gas and urea droplets, thereby facilitating the reduction of the risk of urea crystallization.

[0003] The design idea of ​​the mixer assembly in the related art is usually to use the axial space or radial space of the exhaust gas aftertreatment device to maximize the mixing distance of the exhaust gas and urea droplets. In particular, when the length of the exhaust gas aftertreatment device is limited by the boundary, how to use the radial space to arrange the mixer assembly is particularly important.

[0004] There is a technical solution in the related art that uses an arc-shaped guide plate to guide the exhaust gas to form a swirl. However, this technical solution will cause the airflow to swirl too strongly when it flows out of the arc-shaped guide plate, thereby affecting the uniformity of the airflow distribution on the end face of the downstream post-processing carrier, which is not conducive to improving the conversion efficiency and has a high back pressure.

[0005] Therefore, it is necessary to improve the mixer assembly and the exhaust gas after-treatment device in the related art. Summary of the invention

[0006] The object of the present invention is to provide a mixer assembly and an exhaust gas after-treatment device which can improve airflow distribution and have low back pressure.

[0007] To achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a mixer assembly, comprising: a first baffle, a second baffle, an annular wall and a guide plate; the first baffle and the second baffle are arranged at intervals, the mixer assembly comprises a cavity located between the first baffle and the second baffle, and the annular wall is located at the periphery of the cavity; the annular wall is configured to install a urea nozzle, and the urea nozzle is used to spray atomized urea droplets into the cavity; the guide plate is at least partially located in the cavity, the guide plate comprises a first guide plate and a second guide plate, the mixer assembly comprises an air flow bifurcation located between the first guide plate and the second guide plate along the circumference of the cavity; the mixer assembly comprises a mixing space located between the annular wall and the guide plate, an air flow inlet connected to the mixing space, and an air outlet cavity located on the inner side of the guide plate; the air flow bifurcation connects the mixing space with the air outlet cavity.

[0008] As a further improved technical solution of the present invention, the first guide plate and the second guide plate are two parts, or the first guide plate and the second guide plate are integrally arranged.

[0009] As a further improved technical solution of the present invention, the first guide plate includes a first arcuate wall and a blocking wall connected to the first arcuate wall; the first arcuate wall is conical, and the first arcuate wall includes a first end portion located at one end of the first arcuate wall along the axial direction of the first arcuate wall and a second end portion located at the other end of the first arcuate wall along the axial direction of the first arcuate wall, and the first end portion is fixed to the first baffle.

[0010] As a further improved technical solution of the present invention, the second guide plate includes a second arcuate wall and an extension wall connected to the second arcuate wall, and the extension wall protrudes outwardly from the first arcuate wall along the radial direction of the cavity.

[0011] As a further improved technical solution of the present invention, the extension wall at least partially protrudes into the mixing space to guide a part of the airflow in the mixing space to the airflow bifurcation opening.

[0012] As a further improved technical solution of the present invention, the blocking wall is in contact with the inner wall surface of the annular wall;

[0013] The extension wall is spaced apart from the inner wall surface of the annular wall along the radial direction.

[0014] As a further improved technical solution of the present invention, the mixer assembly further comprises an air flow outlet located between the second guide plate and the blocking wall along the circumferential direction, and the air flow outlet is communicated with the air outlet cavity.

[0015] As a further improved technical solution of the present invention, the first baffle is provided with a through hole located in the middle of the first baffle and an inner wall exposed in the through hole, the through hole is connected to the air outlet cavity, and the first guide plate and the second guide plate are both fixed to the inner wall.

[0016] As a further improved technical solution of the present invention, the first baffle is annular, and includes a first end portion, a second end portion, and a slot located between the first end portion and the second end portion; the blocking wall is fixed to the first end portion, and the second end portion is provided with a bending portion bent into the air outlet cavity, and the bending portion is used to guide a portion of the airflow in the mixing space to the slot.

[0017] As a further improved technical solution of the present invention, the second baffle is integrally formed with the annular wall, and the first baffle is assembled and fixed on the inner wall surface of the annular wall.

[0018] As a further improved technical solution of the present invention, at least one of the first arc-shaped wall and the blocking wall is provided with a plurality of first air flow through holes penetrating the first guide plate, and the first air flow through holes connect the mixing space and the air outlet cavity.

[0019] As a further improved technical solution of the present invention, the first baffle is provided with a plurality of second air flow through holes penetrating the first baffle.

[0020] As a further improved technical solution of the present invention, the mixer assembly further includes at least one urea crushing plate fixed to the first baffle and located in the mixing space.

[0021] As a further improved technical solution of the present invention, the mixer assembly includes a mounting seat fixed on the annular wall, and the urea nozzle is mounted on the mounting seat.

[0022] As a further improved technical solution of the present invention, the mixer assembly includes an airflow inlet pipe integrally formed with the annular wall, the airflow inlet pipe is provided with an airflow inlet channel connected to the airflow inlet, and the airflow inlet channel is directly connected to the mixing space.

[0023] The present invention also discloses an exhaust gas after-treatment device, which includes a shell, an exhaust gas after-treatment carrier encapsulated in the shell, and a mixer assembly connected to the shell, the mixer assembly is the aforementioned mixer assembly, and the air outlet cavity is connected to the inlet end face of the exhaust gas after-treatment carrier.

[0024] Compared with the prior art, the mixer assembly and the exhaust gas after-treatment device of the present invention include guide plates, and the guide plates include a first guide plate and a second guide plate. The mixer assembly includes an airflow bifurcation located between the first guide plate and the second guide plate along the circumference of the cavity. The mixer assembly includes a mixing space located between the annular wall and the guide plate, an airflow inlet connected to the mixing space, and an air outlet cavity located on the inner side of the guide plate. The airflow bifurcation connects the mixing space and the air outlet cavity. A portion of the airflow in the mixing space can flow into the air outlet cavity from the airflow bifurcation, thereby improving the uniformity of airflow distribution and having a lower back pressure. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a three-dimensional schematic diagram of an exhaust gas after-treatment device of the present invention in one embodiment;

[0026] Figure 2 Yes Figure 1 A three-dimensional schematic diagram of the second baffle and the annular wall;

[0027] Figure 3 yes Figure 1 A partial exploded view of the

[0028] Figure 4 yes Figure 3 Further partial exploded perspective view;

[0029] Figure 5 yes Figure 4 Partial three-dimensional exploded view from another angle;

[0030] Figure 6 Yes Figure 3 The right side view of the second baffle, annular wall, flange, mounting seat and urea nozzle. DETAILED DESCRIPTION

[0031] The specific embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings, where if there are several specific embodiments, the features of these embodiments can be combined with each other without conflict. When the description refers to the drawings, unless otherwise specified, the same numbers or symbols in different drawings represent the same or similar elements. The contents described in the following exemplary specific embodiments do not represent all embodiments of the present invention. On the contrary, they are only examples of products consistent with the present invention as recorded in the claims of the present invention.

[0032] The terms used in the present invention are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention. It should be understood that the words "first", "second" and the like used in the specification and claims of the present invention do not indicate any order, quantity or importance, but are only used to distinguish the names of features.

[0033] Please refer to Figures 1 to 6 As shown, the present invention discloses an exhaust gas after-treatment device 100, which includes a housing 1, an exhaust gas after-treatment carrier 2 encapsulated in the housing 1, and a mixer assembly 3 connected to the housing 1. In one embodiment of the present invention, the exhaust gas after-treatment device 100 is used as a pre-stage after-treatment device of a urea dual-injection exhaust gas after-treatment system.

[0034] In the illustrated embodiment of the present invention, the mixer assembly 3 includes a first baffle 4, a second baffle 51, an annular wall 52 and a guide plate 6. The first baffle 4 and the second baffle 51 are spaced apart. The mixer assembly 3 includes a cavity 40 located between the first baffle 4 and the second baffle 51, and the annular wall 52 is located at the periphery of the cavity 40. The annular wall 52 is configured to install a urea nozzle 7, and the urea nozzle 7 is used to spray atomized urea droplets into the cavity 40. The guide plate 6 is at least partially located in the cavity 40, and the guide plate 6 includes a first guide plate 61 and a second guide plate 62. The mixer assembly 3 includes an airflow bifurcation 63 located between the first guide plate 61 and the second guide plate 62 along the circumference of the cavity 40. The mixer assembly 3 includes a mixing space 30 between the annular wall 52 and the guide plate 6, an air flow inlet 50 communicating with the mixing space 30, and an air outlet cavity 60 located inside the guide plate 6. The air flow bifurcation 63 communicates the mixing space 30 with the air outlet cavity 60.

[0035] The first guide plate 61 and the second guide plate 62 are two parts, or the first guide plate 61 and the second guide plate 62 are integrally arranged. In the illustrated embodiment of the present invention, the first guide plate 61 and the second guide plate 62 are two parts. The second baffle plate 51 is integrally formed with the annular wall 52 to form an end cover 5, and the first baffle plate 4 is assembled and fixed on the inner wall surface 521 of the annular wall 52. In the illustrated embodiment of the present invention, the mixer assembly 3 includes an airflow inlet pipe 522 integrally formed with the annular wall 52, and the airflow inlet pipe 522 is provided with an airflow inlet channel 520 connected to the airflow inlet 50, and the airflow inlet channel 520 is directly connected to the mixing space 30.

[0036] In the illustrated embodiment of the present invention, the mixer assembly 3 includes a mounting seat 71 fixed on the annular wall 52 , and the urea nozzle 7 is mounted on the mounting seat 71 .

[0037] Specifically, in the illustrated embodiment of the present invention, the first guide plate 61 includes a first arcuate wall 611 and a blocking wall 612 connected to the first arcuate wall 611. The first arcuate wall 611 is tapered, and the first arcuate wall 611 includes a first end portion 6111 located at one end of the first arcuate wall 611 along the axial direction of the first arcuate wall 611 and a second end portion 6112 located at the other end of the first arcuate wall 611 along the axial direction of the first arcuate wall 611, and the first end portion 6111 is fixed to the first baffle 4.

[0038] In the illustrated embodiment of the present invention, the second guide plate 62 includes a second arcuate wall 621 and an extension wall 622 connected to the second arcuate wall 621 . The extension wall 622 protrudes outwardly from the first arcuate wall 611 along the radial direction of the cavity 40 .

[0039] The extension wall 622 at least partially protrudes into the mixing space 30 to guide a portion of the airflow in the mixing space 30 to the airflow bifurcation opening 63 .

[0040] In the illustrated embodiment of the present invention, the blocking wall 612 is attached to the inner wall surface 521 of the annular wall 52. Specifically, in one embodiment of the present invention, the blocking wall 612 is fixed to the inner wall surface 521 of the annular wall 52 by welding.

[0041] The extension wall 622 is spaced apart from the inner wall surface 521 of the annular wall 52 along the radial direction to form an opening for air flow.

[0042] The mixer assembly 3 further includes an air flow outlet 80 located between the second guide plate 62 and the blocking wall 612 along the circumferential direction, and the air flow outlet 80 is communicated with the air outlet cavity 60 .

[0043] In the illustrated embodiment of the present invention, the first baffle plate 4 is provided with a through hole 41 located in the middle of the first baffle plate 4 and an inner wall 42 exposed in the through hole 41, the through hole 41 is connected to the gas outlet cavity 60, and the first guide plate 61 and the second guide plate 62 are both fixed to the inner wall 42. Specifically, the first baffle plate 4 is annular, and includes a first end portion 43, a second end portion 44, and a slot 45 located between the first end portion 43 and the second end portion 44. The blocking wall 612 is fixed to the first end portion 43, and the second end portion 44 is provided with a bent portion 46 bent toward the gas outlet cavity 60, and the bent portion 46 is used to guide a portion of the airflow in the mixing space 30 to the slot 45.

[0044] At least one of the first arcuate wall 611 and the blocking wall 612 is provided with a plurality of first airflow through holes 610 penetrating the first guide plate 61, and the first airflow through holes 610 connect the mixing space 30 and the air outlet cavity 60. In the illustrated embodiment of the present invention, both the first arcuate wall 611 and the blocking wall 612 are provided with a plurality of first airflow through holes 610 penetrating the first guide plate 61 to adjust the back pressure.

[0045] In the illustrated embodiment of the present invention, the first baffle plate 4 is provided with a plurality of second air flow through holes 47 penetrating the first baffle plate 4 to adjust the back pressure.

[0046] The mixer assembly 3 further includes at least one urea crushing plate 9 fixed to the first baffle 4 and located in the mixing space 30. In the illustrated embodiment of the present invention, the urea crushing plates 9 are multiple (for example, three) and are located in the injection area of ​​the urea nozzle 7. The urea crushing plates 9 are arranged in parallel to each other to crush the urea droplets sprayed onto the urea crushing plates 9, thereby facilitating the crushing of urea particles into smaller pieces and reducing the risk of urea crystallization.

[0047] The working principle of the exhaust gas post-treatment device 100 of the present invention is as follows: first, the exhaust gas from the engine flows into the airflow inlet channel 520 from the airflow inlet 50; then, the airflow enters the mixing space 30; when the injection condition is reached, the urea nozzle 7 sprays atomized urea droplets into the mixing space 30, and the exhaust gas and the urea droplets are mixed and form a rotating airflow under the guidance of the first guide plate 61; of course, a small part of the airflow directly passes through the first airflow perforation 610 and the second airflow perforation 47, and flows downstream to improve the back pressure. The rotating airflow hits the urea crushing plate 9, which can crush the urea into smaller particles on the one hand, and guide the airflow on the other hand. Then, under the obstruction of the extension wall 622, a part of the airflow is directed to the airflow bifurcation 63, and thus enters the air outlet cavity 60; another part of the airflow bypasses the extension wall 622 and flows further downstream, and finally enters the air outlet cavity 60 from the airflow outlet 80; in addition, some airflow bypassing the extension wall 622 flows downstream from the slot 45. Finally, the airflow can be relatively evenly distributed on the inlet end face of the exhaust gas post-treatment carrier 2, which is beneficial to improve the conversion efficiency. In addition, by flowing a part of the airflow into the air outlet cavity 60 from the airflow bifurcation 63, the amount of airflow entering the air outlet cavity 60 from the airflow outlet 80 is reduced, thereby weakening the swirl effect generated by the airflow entering the air outlet cavity 60 from the airflow outlet 80. In addition, the airflow flowing into the air outlet cavity 60 from the airflow bifurcation port 63 and the airflow entering the air outlet cavity 60 from the airflow outlet 80 will produce mutual impact, further weakening the swirl effect of the airflow, which is beneficial to improving the uniformity of the airflow when flowing through the inlet end face of the exhaust gas after-treatment carrier 2.

[0048] Compared with the prior art, the exhaust gas aftertreatment device 100 of the present invention utilizes the space of the cross section to form a swirl flow in the airflow, thereby increasing the mixing distance between the exhaust gas and the urea droplets, which is beneficial to reducing the risk of urea crystallization. In addition, by providing the airflow bifurcation 63, a part of the airflow first flows into the air outlet cavity 60, and then mixes with another part of the airflow entering the air outlet cavity 60 from the airflow outlet 80, which is beneficial to weakening the swirl flow flowing out of the guide plate 6, thereby improving the uniformity of airflow distribution and reducing back pressure.

[0049] The above embodiments are only used to illustrate the present invention but not to limit the technical solutions described in the present invention. The understanding of this specification should be based on the technicians in the relevant technical field. Although this specification has described the present invention in detail with reference to the above embodiments, ordinary technicians in the field should understand that technicians in the relevant technical field can still modify or replace the present invention with equivalents, and all technical solutions and improvements that do not depart from the spirit and scope of the present invention should be covered within the scope of the claims of the present invention.

Claims

1. A mixer assembly, characterized in that: include: A first baffle, a second baffle, an annular wall and a guide plate; the first baffle and the second baffle are spaced apart, the mixer assembly comprises a cavity between the first baffle and the second baffle, and the annular wall is located at the periphery of the cavity; the annular wall is configured to install a urea nozzle, and the urea nozzle is used to spray atomized urea droplets into the cavity; the guide plate is at least partially located in the cavity, the guide plate comprises a first guide plate and a second guide plate, and the mixer assembly comprises an air flow bifurcation located between the first guide plate and the second guide plate along the circumference of the cavity; the mixer assembly comprises a mixing space between the annular wall and the guide plate, an air flow inlet connected to the mixing space, and an air outlet cavity located on the inner side of the guide plate; the air flow bifurcation connects the mixing space with the air outlet cavity.

2. The mixer assembly according to claim 1, characterized in that: The first guide plate and the second guide plate are two parts, or the first guide plate and the second guide plate are integrally arranged.

3. The mixer assembly according to claim 1, characterized in that: The first guide plate includes a first arcuate wall and a blocking wall connected to the first arcuate wall; the first arcuate wall is conical, and the first arcuate wall includes a first end portion located at one end of the first arcuate wall along the axial direction of the first arcuate wall and a second end portion located at the other end of the first arcuate wall along the axial direction of the first arcuate wall, and the first end portion is fixed to the first baffle.

4. The mixer assembly according to claim 3, characterized in that: The second guide plate includes a second arc-shaped wall and an extension wall connected to the second arc-shaped wall, and the extension wall protrudes outward from the first arc-shaped wall along the radial direction of the cavity.

5. The mixer assembly according to claim 4, characterized in that: The extension wall at least partially protrudes into the mixing space to guide a portion of the airflow in the mixing space to the airflow bifurcation opening.

6. The mixer assembly according to claim 4, characterized in that: The blocking wall is in contact with the inner wall surface of the annular wall; The extension wall is spaced apart from the inner wall surface of the annular wall along the radial direction.

7. The mixer assembly according to claim 3, characterized in that: The mixer assembly further includes an air flow outlet located between the second guide plate and the blocking wall along the circumferential direction, and the air flow outlet is communicated with the air outlet cavity.

8. The mixer assembly of claim 1, wherein: The first baffle is provided with a through hole located in the middle of the first baffle and an inner wall exposed in the through hole, the through hole is communicated with the air outlet cavity, and the first guide plate and the second guide plate are both fixed to the inner wall.

9. The mixer assembly of claim 3, wherein: The first baffle is annular and includes a first end portion, a second end portion, and a slot between the first end portion and the second end portion; the blocking wall is fixed to the first end portion, and the second end portion is provided with a bending portion bent into the air outlet cavity, and the bending portion is used to guide a portion of the airflow in the mixing space to the slot.

10. The mixer assembly of claim 1, wherein: The second baffle is integrally formed with the annular wall, and the first baffle is assembled and fixed on the inner wall surface of the annular wall.

11. The mixer assembly of claim 3, wherein: At least one of the first arc-shaped wall and the blocking wall is provided with a plurality of first air flow through holes penetrating the first guide plate, and the first air flow through holes are connected with the mixing space and the air outlet cavity.

12. The mixer assembly of claim 1, wherein: The first baffle is provided with a plurality of second air flow through holes penetrating the first baffle.

13. The mixer assembly of claim 1, wherein: The mixer assembly further includes at least one urea breaking plate fixed to the first baffle and located in the mixing space.

14. The mixer assembly of claim 1, wherein: The mixer assembly comprises a mounting seat fixed on the annular wall, and the urea nozzle is mounted on the mounting seat.

15. The mixer assembly of claim 1, wherein: The mixer assembly comprises an airflow inlet pipe integrally formed with the annular wall, the airflow inlet pipe is provided with an airflow inlet channel connected with the airflow inlet, and the airflow inlet channel is directly connected with the mixing space.

16. An exhaust gas post-treatment device, characterized in that: It comprises a shell, an exhaust gas after-treatment carrier encapsulated in the shell, and a mixer assembly connected to the shell, wherein the mixer assembly is the mixer assembly as described in any one of claims 1 to 15, and the gas outlet cavity is connected to the inlet end face of the exhaust gas after-treatment carrier.

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