Mixing pipe assembly and exhaust aftertreatment device

Abstract

A mixing tube assembly includes a mixing tube, a cyclone tube partially installed within the mixing tube, a baffle, a porous tube installed within the cyclone tube, and a urea crushing bowl installed within the mixing tube and located downstream of the cyclone tube. An annular space is formed between the mixing tube and the cyclone tube, and the baffle is located within the annular space to divide it into a first space and a second space. The cyclone tube has a plurality of fins communicating with the first space. The urea crushing bowl includes an arcuate surface for crushing urea droplets and an opening located in the middle of the arcuate surface. Compared with the prior art, this invention provides a urea crushing bowl, and at least some urea droplets can be struck on the arcuate surface of the urea crushing bowl. This configuration further reduces the volume of urea droplets, which is beneficial for increasing the urea evaporation time and distance, and reducing the risk of urea crystallization. This invention also relates to a tail gas aftertreatment device having this mixing tube assembly.

Description

Technical Field

[0001] This invention relates to a mixing pipe assembly and an exhaust aftertreatment device, belonging to the field of diesel engine exhaust aftertreatment technology. Background Technology

[0002] Diesel engine exhaust aftertreatment systems typically include a housing and encapsulated components such as diesel catalytic oxidizer (DOC), diesel particulate filter (DPF), and selective catalytic reduction (SCR). To improve performance, these systems often also include a mixing unit located downstream of the DPF and upstream of the SCR. With increasingly stringent emission regulations, optimizing the performance of this mixing unit is a key technical challenge that needs to be addressed. Summary of the Invention

[0003] The purpose of this invention is to provide a mixing tube assembly that can promote urea evaporation and an exhaust gas aftertreatment device having the mixing tube assembly.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: a mixing tube assembly, comprising a mixing tube, a swirl tube partially installed in the mixing tube, a baffle installed between the mixing tube and the swirl tube, a porous tube installed in the swirl tube, and a urea crushing bowl installed in the mixing tube and located downstream of the swirl tube. An annular space is formed between the mixing tube and the swirl tube. The baffle is located in the annular space to divide the annular space into a first space upstream of the baffle and a second space downstream of the baffle. The baffle has at least one communicating hole connecting the first space and the second space. The swirl tube has a first section and a second section downstream of the first section. The first section has a plurality of fins for guiding airflow to form a swirl, and the plurality of fins are connected to the first space. The second section has a plurality of first perforations penetrating the peripheral wall surface, and the first perforations are connected to the second space. The urea crushing bowl includes an arcuate surface for crushing urea droplets and an opening located in the middle of the arcuate surface.

[0005] As a further improvement of the present invention, the fin portion is located in the mixing tube and partially protrudes from the mixing tube.

[0006] As a further improvement of the present invention, the baffle is fixed in the second section and close to the first section.

[0007] As a further improvement of the present invention, the mixing tube assembly includes an end cap and a nozzle seat fixed on the end cap. The nozzle seat is used to install a urea nozzle. The swirling tube includes a first end and a second end opposite to the first end. The first end is fixed on the end cap.

[0008] As a further improvement of the present invention, the second end is suspended inside the mixing tube.

[0009] As a further improvement of the present invention, the porous tube is provided with a third end fixed on the end cap and a fourth end opposite to the third end, and the fourth end is provided with a first claw portion for fixing the porous tube on the inner wall of the cyclone tube.

[0010] As a further improved technical solution of the present invention, the opening is located at the center of the arc-shaped surface, and the cyclone tube, the mixing tube, the porous tube and the opening are all coaxially arranged; the urea crushing bowl includes a plurality of second claw portions extending outward from the arc-shaped surface, and the second claw portions are fixed on the inner wall of the mixing tube.

[0011] As a further improved technical solution of the present invention, the porous tube is provided with a third section corresponding to the first section and a fourth section corresponding to the second section, wherein the third section is provided with a plurality of circular third perforations, and the fourth section is provided with a plurality of circular fourth perforations, wherein the diameter of the third perforations is smaller than the diameter of the fourth perforations.

[0012] The present invention also relates to an exhaust gas aftertreatment device, which includes a housing, a first catalyst carrier located within the housing, a second catalyst carrier located downstream of the first catalyst carrier, a third catalyst carrier located downstream of the second catalyst carrier, and a mixing pipe assembly connecting the second catalyst carrier and the third catalyst carrier, wherein the mixing pipe assembly is the aforementioned mixing pipe assembly.

[0013] As a further improvement of the present invention, the first catalyst support is diesel catalytic oxidant (DOC), the second catalyst support is diesel particulate filter (DPF), and the third catalyst support is selective catalytic reduction agent (SCR).

[0014] Compared to existing technologies, this invention features a urea crushing bowl, and at least some urea droplets can be struck on the curved surface of the bowl. This design further reduces the volume of the urea droplets, which helps to increase the evaporation time and distance of urea and reduces the risk of urea crystallization. Furthermore, the baffle allows some of the airflow in the first space to pass through the fins and enter the swirl tube, improving the swirling effect and enhancing mixing performance. Attached Figure Description

[0015] Figure 1 This is a three-dimensional schematic diagram of the exhaust gas aftertreatment device of the present invention.

[0016] Figure 2 It is along Figure 1 A cross-sectional view of line AA in the middle.

[0017] Figure 3 yes Figure 2 A magnified view of part B within the middle frame.

[0018] Figure 4 This is a three-dimensional schematic diagram of the hybrid tube assembly of the present invention.

[0019] Figure 5 yes Figure 4 3D exploded view.

[0020] Figure 6 yes Figure 5 Left view of the urea crushing bowl.

[0021] Figure 7 yes Figure 5 Front view of the urea crushing bowl. Detailed Implementation

[0022] Please refer to Figures 1 to 7 As shown, this invention discloses an exhaust gas aftertreatment device 100, which includes a housing 10, a first catalyst carrier 101 located within the housing 10, a second catalyst carrier 102 located downstream of the first catalyst carrier 101, a third catalyst carrier (not shown) located downstream of the second catalyst carrier 102, and a mixing pipe assembly 200 connecting the second catalyst carrier 102 and the third catalyst carrier. The housing 10 is provided with an air inlet 103 and an air outlet 104. In one embodiment of this invention, the first catalyst carrier 101 is a diesel catalytic oxidant (DOC), the second catalyst carrier 102 is a diesel particulate filter (DPF), and the third catalyst carrier is a selective catalytic reduction agent (SCR).

[0023] The mixing tube assembly 200 includes a cylindrical mixing tube 1, a swirl tube 2 partially installed in the mixing tube 1, a baffle 3 installed between the mixing tube 1 and the swirl tube 2, a porous tube 4 installed in the swirl tube 2, a urea crushing bowl 9 installed in the mixing tube 1 and located downstream of the swirl tube 2, an end cap 5 installed at one end of the swirl tube 2, and a nozzle seat 6 fixed to the end cap 5. The nozzle seat 6 is used to install a urea nozzle (not shown) to spray atomized urea droplets into the porous tube 4.

[0024] The swirling tube 2 has a first section 21 and a second section 22 located downstream of the first section 21. The first section 21 has several fins 211 for guiding airflow to form a swirling flow, and the second section 22 has several first perforations 221 penetrating the peripheral wall. The fins 211 are partially located within the mixing tube 1 and partially protrude from it. The swirling tube 2 includes a first end 210 and a second end 220 opposite to the first end 210. The first end 210 is fixed to the end cap 5, and the second end 220 is suspended within the mixing tube 1 (e.g., ...). Figure 3 (As shown).

[0025] An annular space 20 is formed between the mixing tube 1 and the cyclone tube 2. A baffle 3 is located within the annular space 20 to divide it into a first space 201 upstream of the baffle 3 and a second space 202 downstream of the baffle 3. The baffle 3 is provided with at least one connecting hole 31 (e.g., ...) connecting the first space 201 and the second space 202. Figure 5 (As shown in the figure). In the embodiment illustrated in the present invention, there are multiple communicating holes 31 evenly distributed on the circumference to uniformly adjust the airflow distribution. The plurality of fins 211 are connected to the first space 201. Please refer to... Figure 3 As shown, the first perforation 221 is connected to the second space 202; the baffle 3 is fixed to the second section 22 and close to the first section 21, so that part of the airflow in the first space 201 passes through the fin 211 and enters the cyclone tube 2.

[0026] The porous tube 4 has a third end 41 fixed to the end cap 5 and a fourth end 42 opposite to the third end 41. The fourth end 42 has a first claw portion 421 for fixing the porous tube 4 to the inner wall of the cyclone tube 2. The porous tube 4 has a third section 43 corresponding to the first section 21 and a fourth section 44 corresponding to the second section 22. The third section 43 has a plurality of circular third through holes 431, and the fourth section 44 has a plurality of circular fourth through holes 441. The diameter of the third through holes 431 is smaller than the diameter of the fourth through holes 441.

[0027] The urea crushing bowl 9 includes an arc-shaped surface 91 for crushing urea droplets, an opening 92 located in the middle of the arc-shaped surface 91, and a plurality of second claw portions 93 extending outward from the arc-shaped surface 91. The second claw portions 93 are fixed to the inner wall of the mixing tube 1. In the embodiment illustrated in the present invention, the opening 92 is located at the center of the arc-shaped surface 91, and the vortex tube 2, the mixing tube 1, the porous tube 4, and the opening 92 are all coaxially arranged.

[0028] Compared to existing technologies, this invention features a urea crushing bowl 9, and at least some urea droplets can hit the arc-shaped surface 91 of the urea crushing bowl 9. This design further reduces the volume of the urea droplets, which is beneficial for increasing the urea evaporation time and distance, and reducing the risk of urea crystallization. The baffle 3 allows part of the airflow in the first space 201 to pass through the fins 211 and enter the vortex tube 2, improving the vortex effect and enhancing the mixing performance.

[0029] The above embodiments are only used to illustrate the present invention and are not intended to limit the technical solutions described in the present invention. The understanding of this specification should be based on those skilled in the art. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still make modifications or equivalent substitutions to the present invention. 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 hybrid tube assembly, characterized in that, The device includes a mixing tube, a swirl tube partially installed within the mixing tube, a baffle plate installed between the mixing tube and the swirl tube, a porous tube installed within the swirl tube, and a urea crushing bowl installed within the mixing tube and located downstream of the swirl tube. An annular space is formed between the mixing tube and the swirl tube. The baffle plate is located within the annular space to divide it into a first space upstream of the baffle plate and a second space downstream of the baffle plate. The baffle plate has at least one connecting hole connecting the first space and the second space. The swirl tube has a first section and a second section downstream of the first section. The first section has several fins that guide airflow to form a swirl, and these fins are connected to the first space. The second section has several first perforations penetrating its peripheral wall, and these first perforations are connected to the second space. The urea crushing bowl includes an arc-shaped surface for crushing urea droplets and an opening located in the middle of the arc-shaped surface. The opening is located at the center of the arc-shaped surface, and the cyclone tube, the mixing tube, the porous tube and the opening are all coaxially arranged; the urea crushing bowl and the cyclone tube are arranged at intervals along the axial direction of the mixing tube; the urea crushing bowl includes a plurality of second claw portions extending outward from the arc-shaped surface, and the second claw portions are fixed on the inner wall of the mixing tube.

2. The hybrid tube assembly as claimed in claim 1, characterized in that: The fins are located in the mixing tube and partially protrude from the mixing tube.

3. The hybrid tube assembly as claimed in claim 1, characterized in that: The baffle is fixed in the second section and close to the first section.

4. The hybrid tube assembly as claimed in claim 1, characterized in that: The mixing tube assembly includes an end cap and a nozzle seat fixed to the end cap, the nozzle seat being used to mount a urea nozzle, and the cyclone tube including a first end and a second end opposite to the first end, the first end being fixed to the end cap.

5. The hybrid tube assembly as claimed in claim 4, characterized in that: The second end is suspended inside the mixing tube.

6. The hybrid tube assembly as claimed in claim 5, characterized in that: The porous tube has a third end fixed to the end cap and a fourth end opposite to the third end. The fourth end has a first claw for fixing the porous tube to the inner wall of the cyclone tube.

7. The hybrid tube assembly as claimed in claim 1, characterized in that: The porous tube has a third section corresponding to the first section and a fourth section corresponding to the second section. The third section has a plurality of circular third perforations, and the fourth section has a plurality of circular fourth perforations. The diameter of the third perforations is smaller than the diameter of the fourth perforations.

8. An exhaust gas aftertreatment device, comprising a housing, a first catalyst carrier located within the housing, a second catalyst carrier located downstream of the first catalyst carrier, a third catalyst carrier located downstream of the second catalyst carrier, and a mixing pipe assembly connecting the second catalyst carrier and the third catalyst carrier, characterized in that: The hybrid tube assembly is the hybrid tube assembly described in any one of claims 1 to 7.

9. The exhaust gas aftertreatment device as described in claim 8, characterized in that: The first catalyst support is diesel catalytic oxidant (DOC), the second catalyst support is diesel particulate filter (DPF), and the third catalyst support is selective catalytic reduction agent (SCR).

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