Mixing cavity assembly and tail gas after-treatment device

Abstract

A mixing cavity assembly comprises a shell, a mixing pipe assembly and a flow guide cover. The mixing cavity assembly is provided with a urea nozzle supporting seat, and the urea nozzle supporting seat is configured to be used for supporting a urea nozzle. The mixing pipe assembly comprises a mixing pipe, and the mixing pipe is provided with a first airflow hole and a second airflow hole. The flow guide cover is at least partially fixed in the mixing pipe so as to divide the mixing pipe into a first cavity and a second cavity. The first cavity is communicated with the first airflow hole, and the second cavity is communicated with the second airflow hole. The flow guide cover is provided with a plate-shaped part and a protruding part, and the protruding part is provided with a through hole communicated with the second cavity. According to the utility model, the flow guide cover is arranged, so that a urea liquid film adhered near the urea nozzle can be heated by utilizing the high temperature of tail gas, and the risk of urea crystallization is reduced. The utility model further discloses a tail gas after-treatment device comprising the mixing cavity assembly.

Description

Technical Field

[0001] The utility model relates to a mixing chamber assembly and an exhaust gas aftertreatment device, belonging to the technical field of engine exhaust gas aftertreatment. Background Technique

[0002] The exhaust gas aftertreatment device in the related art generally includes a housing, a mixing pipe located in the housing, and a urea nozzle mounted on the housing and used for injecting urea droplets into the mixing pipe. Among them, how to solve the urea crystallization problem near the urea nozzle is one of the technical problems faced by those skilled in the art.

[0003] Therefore, it is necessary to provide a new solution to solve this technical problem. Summary of the Utility Model

[0004] The purpose of the utility model is to provide a mixing chamber assembly and an exhaust gas aftertreatment device with strong anti-crystallization ability.

[0005] To achieve the above purpose, the utility model adopts the following technical scheme: A mixing chamber assembly is used in an exhaust gas aftertreatment device. The mixing chamber assembly includes a housing, a mixing pipe assembly fixed in the housing, and a diversion cover fixed to the mixing pipe assembly. The housing is provided with an air inlet and an air outlet, and at least part of the mixing pipe assembly is located on the flow path between the air inlet and the air outlet. The mixing chamber assembly is provided with a urea nozzle support seat configured to support a urea nozzle, and the urea nozzle is configured to at least partially pass through the diversion cover and inject atomized urea droplets into the mixing pipe assembly. The diversion cover is close to the urea nozzle support seat. The mixing pipe assembly includes a mixing pipe, the mixing pipe is provided with a first air hole communicating with the air inlet and a second air hole close to the urea nozzle support seat. At least part of the diversion cover is fixed in the mixing pipe to divide the mixing pipe into a first cavity on one side of the diversion cover and a second cavity on the other side of the diversion cover. The first cavity is communicated with the first air hole, the second cavity is communicated with the second air hole, the diversion cover is provided with a plate-shaped part and a raised part protruding from the plate-shaped part and protruding into the second cavity, and the raised part is provided with a through hole communicating with the second cavity.

[0006] As a further improved technical scheme of the utility model, the mixing chamber assembly includes a cylinder body fixed on the housing. The cylinder body includes an inner cavity, the urea nozzle support seat is fixed to the cylinder body, and the inner cavity is communicated with the second cavity.

[0007] As a further improved technical solution of the present utility model, the cylinder body includes a first end and a second end opposite to the first end, and the inner cavity body is located between the first end and the second end; the urea nozzle support seat is fixed to the first end of the cylinder body and at least partially protrudes downward into the inner cavity body.

[0008] As a further improved technical solution of the present utility model, the cylinder body is in the shape of a hollow cylinder; the urea nozzle support seat includes a cylindrical wall portion and a bottom wall located at the bottom of the wall portion, at least part of the wall portion is located in the cylinder body, and the bottom wall is located between the first end and the second end of the cylinder body; the bottom wall is provided with a spray hole corresponding to the urea nozzle.

[0009] As a further improved technical solution of the present utility model, the raised portion and the bottom wall are spaced from each other in the vertical direction, and the spray hole is directly opposite to the through hole.

[0010] As a further improved technical solution of the present utility model, the plate-like portion is located below the second end of the cylinder body, and the raised portion protrudes upward beyond the second end of the cylinder body to at least partially protrude into the inner cavity body.

[0011] As a further improved technical solution of the present utility model, the second air flow hole is in the shape of a round hole and / or an arc-shaped strip.

[0012] As a further improved technical solution of the present utility model, the mixing tube assembly includes a plurality of stepped plates installed on the mixing tube.

[0013] As a further improved technical solution of the present utility model, no other holes are provided on the flow guide cover except the through hole.

[0014] The present utility model also discloses an exhaust gas after-treatment device, which includes the aforementioned mixing chamber assembly, a first after-treatment carrier located upstream of the mixing chamber assembly, and a second after-treatment carrier located downstream of the mixing chamber assembly.

[0015] Compared with the prior art, the mixing chamber assembly and the exhaust gas aftertreatment device of the present utility model include a diversion cover, at least a part of which is fixed in the mixing pipe to divide the mixing pipe into a first cavity on one side of the diversion cover and a second cavity on the other side of the diversion cover. The first cavity is communicated with the first air flow hole, and the second cavity is communicated with the second air flow hole. The diversion cover is provided with a plate-shaped part and a raised part protruding from the plate-shaped part and protruding into the second cavity. The raised part is provided with a through hole communicated with the second cavity. By arranging the diversion cover, the air flow flowing into the second cavity from the second air flow hole can flow to a position close to the end of the urea nozzle under the guidance of the diversion cover, which is beneficial to heating the urea liquid film adhered near the urea nozzle by the high temperature of the exhaust gas, promoting its evaporation, and thus reducing the risk of urea crystallization. In addition, the diversion cover can direct the air flow flowing into the second cavity from the second air flow hole to a position close to the end of the urea nozzle, which is beneficial to purging the urea droplets that may form urea crystallization by the air flow, and thus further reducing the risk of urea crystallization. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a perspective schematic view of the exhaust gas aftertreatment device of the present utility model in one embodiment.

[0017] Figure 2 is Figure 1 a partial perspective exploded view of

[0018] Figure 3 is a perspective schematic view of the mixing chamber assembly of the present utility model.

[0019] Figure 4 is Figure 3 a perspective schematic view from another angle.

[0020] Figure 5 is along Figure 4 the sectional schematic view taken along the line A-A in , in which the urea nozzle, the urea spray beam and the air flow direction are shown by dashed lines.

[0021] Figure 6 is a perspective exploded view of the mixing chamber assembly of the present utility model.

[0022] Figure 7 is Figure 6 a perspective exploded view from another angle.

[0023] Figure 8 is Figure 2 a perspective schematic view when the diversion cover and the mixing pipe assembly in are installed together.

[0024] Figure 9 is Figure 8Schematic perspective view of the diversion cover in Detailed implementation manners

[0025] The following will describe in detail the specific implementation manners of the present utility model in conjunction with the accompanying drawings. Among them, if there are several specific implementation manners, and in the case of no conflict, the features in these implementation manners can be combined with each other. When the description involves the accompanying drawings, unless otherwise specified, the same numbers or symbols in different drawings represent the same or similar elements. The content described in the following exemplary specific implementation manners does not represent all implementation manners of the present utility model. On the contrary, they are only examples of products that are consistent with the present utility model as recorded in the claims of the present utility model.

[0026] The terms used in the present utility model are only for the purpose of describing specific implementation manners, and are not intended to limit the protection scope of the present utility model. It should be understood that the terms used in the description and claims of the present utility model, such as "first", "second" and similar terms, do not represent any order, quantity or importance, but are only used to distinguish the named features.

[0027] Please refer to Figures 1 to 9 As shown, the illustrated implementation manner of the present utility model discloses an exhaust gas post-treatment device 400, which includes a mixing chamber assembly 100, a first post-treatment carrier 200 located upstream of the mixing chamber assembly 100, and a second post-treatment carrier 300 located downstream of the mixing chamber assembly 100.

[0028] The mixing chamber assembly 100 includes a housing 1, a mixing tube assembly 2 fixed in the housing 1, a diversion cover 3 fixed to the mixing tube assembly 2, a cylinder 4 fixed to the housing 1, and a urea nozzle support base 5 fixed to the cylinder 4.

[0029] In the illustrated implementation manner of the present utility model, the housing 1 is provided with an air inlet 11 and an air outlet 12, and at least a part of the mixing tube assembly 2 is located on the flow path between the air inlet 11 and the air outlet 12.

[0030] The urea nozzle support base 5 is configured to support a urea nozzle 6, and the urea nozzle 6 is configured to at least partially pass through the diversion cover 3 and spray atomized urea droplets into the mixing tube assembly 2. The diversion cover 3 is close to the urea nozzle support base 5.

[0031] The mixing tube assembly 2 includes a mixing tube 21 and a plurality of stepped plates 22 mounted on the mixing tube 21. In an implementation manner of the present utility model, the plates 22 are welded and fixed to the mixing tube 21 to break the urea droplets impinging on the plates 22.

[0032] In the illustrated embodiment of the present utility model, the mixing tube 21 is generally tubular, and is provided with a blocking wall portion 211 facing the air flow inlet 11 and an opening portion 212 facing away from the blocking wall portion 211. The mixing tube 21 is provided with a first air flow hole 213 communicating with the air flow inlet 11 and a second air flow hole 214 close to the urea nozzle support seat 5. In the illustrated embodiment of the present utility model, both the first air flow hole 213 and the second air flow hole 214 are provided on the blocking wall portion 211.

[0033] The first air flow holes 213 are several and distributed on the blocking wall portion 211. Those skilled in the art can understand that the size, shape, etc. of the first air flow holes 213 can be flexibly adjusted as needed. By providing the first air flow holes 213, it is beneficial to make the vast majority of the air flow from the air flow inlet 11 pass through the first air flow holes 213 relatively evenly and enter the mixing tube 21.

[0034] The second air flow hole 214 is in the shape of a round hole and / or an arc-shaped strip.

[0035] The guiding cover 3 is at least partially fixed in the mixing tube 21 to divide the mixing tube 21 into a first cavity 215 on one side (for example, the lower side) of the guiding cover 3 and a second cavity 216 on the other side (for example, the upper side) of the guiding cover 3. The first cavity 215 communicates with the first air flow hole 213, and the second cavity 216 communicates with the second air flow hole 214. The guiding cover 3 is provided with a plate-shaped portion 31 and a raised portion 32 protruding from the plate-shaped portion 31 and protruding into the second cavity 216. The raised portion 32 is provided with a through hole 320 communicating with the second cavity 216.

[0036] The cylinder body 4 can install the urea nozzle 6 through a holding member such as a clamp. The cylinder body 4 includes an inner cavity 40, and the urea nozzle support seat 5 is fixed to the cylinder body 4. The inner cavity 40 communicates with the second cavity 216.

[0037] In the illustrated embodiment of the present utility model, the cylinder body 4 is in the shape of a hollow cylinder. The cylinder body 4 includes a first end 41 and a second end 42 opposite to the first end 41. The inner cavity 40 is located between the first end 41 and the second end 42. The urea nozzle support seat 5 is fixed to the first end 41 of the cylinder body 4 and at least partially protrudes downward into the inner cavity 40.

[0038] The urea nozzle support seat 5 includes a cylindrical wall portion 51 and a bottom wall 52 located at the bottom of the wall portion 51. At least part of the wall portion 51 is located in the cylinder 4, and the bottom wall 52 is located between the first end 41 and the second end 42 of the cylinder 4 in the vertical direction. The bottom wall 52 is provided with a spray hole 520 corresponding to the urea nozzle 6. The raised portion 32 and the bottom wall 52 are spaced apart from each other in the vertical direction, and the spray hole 520 is aligned with the through hole 320. The plate-like portion 31 is located below the second end 42 of the cylinder 4, and the raised portion 32 protrudes upward beyond the second end 42 of the cylinder 4 to at least partially protrude into the inner cavity 40.

[0039] No other holes are provided on the flow guide cover 3 except the through hole 320. The flow guide cover 3 is generally in the shape of a round cap. The plate-like portion 31 is circular, similar to the brim of a round cap.

[0040] When the exhaust gas flows from the gas flow inlet 11 to the mixing tube assembly 2, most of the exhaust gas passes through the first gas flow hole 213 and enters the first cavity 215 of the mixing tube 21, and a part of the exhaust gas passes through the second gas flow hole 214 and enters the second cavity 216 and the inner cavity 40. Those skilled in the art can understand that the high-temperature exhaust gas entering the second cavity 216 and the inner cavity 40 can heat the end portion near the spray hole of the urea nozzle 6, which is beneficial to heating the urea liquid film adhered near the urea nozzle 6 by the high temperature of the exhaust gas, promoting its evaporation, and thus reducing the risk of urea crystallization. In addition, the flow guide cover 3 can direct the air flow flowing into the second cavity 216 from the second gas flow hole 214 to a position close to the end portion of the urea nozzle 6, which is beneficial to purging the urea droplets that may form urea crystals by the air flow, and thus further reducing the risk of urea crystallization. By providing the flow guide cover 3, it is also possible to reduce the deposition of the urea droplets ejected from the urea nozzle 6 near the urea nozzle 6 due to the influence of the disordered air flow.

[0041] When the injection condition is reached, the urea nozzle 6 injects atomized urea droplets downward, and the urea droplets are mixed with the exhaust gas. The urea droplets hitting the plate 22 are broken into smaller particles, which is beneficial to the evaporation of urea. The mixed gas flow of the urea droplets and the exhaust gas in the second cavity 216 and the inner cavity 40 flows into the first cavity 215 from the through hole 320.

[0042] The above embodiments are only used to illustrate the present utility model and do not limit the technical solutions described in the present utility model. The understanding of this specification should be based on those skilled in the relevant technical field. Although this specification has described the present utility model in detail with reference to the above embodiments, those of ordinary skill in the art should understand that those skilled in the relevant technical field can still modify the present utility model or make equivalent replacements, and all technical solutions and their improvements that do not depart from the spirit and scope of the present utility model should be covered within the scope of the claims of the present utility model.

Claims

1. A mixing chamber assembly, used in an exhaust gas aftertreatment device, characterized in that: The mixing chamber assembly comprises a shell, a mixing tube assembly fixed in the shell, and a guide cover fixed to the mixing tube assembly; the shell is provided with an airflow inlet and an airflow outlet, and the mixing tube assembly is at least partially located on the flow channel between the airflow inlet and the airflow outlet; the mixing chamber assembly is provided with a urea nozzle support seat, the urea nozzle support seat is configured to support a urea nozzle, and the urea nozzle is configured to at least partially pass through the guide cover and spray atomized urea droplets into the mixing tube assembly; the guide cover is close to the urea nozzle support seat; the mixing tube assembly comprises a mixing tube assembly; The mixing tube is provided with a first air flow hole communicating with the air flow inlet and a second air flow hole close to the urea nozzle support seat, the guide cover is at least partially fixed in the mixing tube to divide the mixing tube into a first cavity located on one side of the guide cover and a second cavity located on the other side of the guide cover, the first cavity is communicated with the first air flow hole, the second cavity is communicated with the second air flow hole, the guide cover is provided with a plate-like portion and a raised portion protruding from the plate-like portion and protruding into the second cavity, and the raised portion is provided with a through hole communicating with the second cavity.

2. The mixing chamber assembly according to claim 1, characterized in that: The mixing chamber assembly comprises a cylinder fixed on the shell, the cylinder comprises an inner cavity, the urea nozzle support seat is fixed to the cylinder, and the inner cavity is communicated with the second cavity.

3. The mixing chamber assembly according to claim 2, characterized in that: The cylinder comprises a first end and a second end opposite to the first end, and the inner cavity is located between the first end and the second end; the urea nozzle support seat is fixed to the first end of the cylinder and at least partially protrudes downward into the inner cavity.

4. The mixing chamber assembly according to claim 3, characterized in that: The barrel is in a hollow cylindrical shape; the urea nozzle support seat includes a cylindrical wall portion and a bottom wall located at the bottom of the wall portion, the wall portion is at least partially located in the barrel, and the bottom wall is located between the first end of the barrel and the second end of the barrel; the bottom wall is provided with a spray hole corresponding to the urea nozzle.

5. The mixing chamber assembly according to claim 4, characterized in that: The raised portion and the bottom wall are spaced apart from each other in the up-down direction, and the spray hole faces the through hole.

6. The mixing chamber assembly according to claim 3, characterized in that: The plate-shaped portion is located below the second end of the cylinder, and the raised portion protrudes upward beyond the second end of the cylinder to at least partially protrude into the inner cavity.

7. The mixing chamber assembly according to claim 1, characterized in that: The second air flow holes are in the shape of circular holes and / or arc strips.

8. The mixing chamber assembly according to claim 1, characterized in that: The mixing tube assembly includes a plurality of stepped plates mounted on the mixing tube.

9. The mixing chamber assembly according to claim 1, characterized in that: Except for the through hole, no other holes are arranged on the guide cover.

10. An exhaust gas post-treatment device, characterized in that: The invention comprises a mixing chamber assembly as claimed in any one of claims 1 to 9, a first after-treatment carrier located upstream of the mixing chamber assembly, and a second after-treatment carrier located downstream of the mixing chamber assembly.

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