Adjustable compact scr mixer and aftertreatment system

Abstract

The utility model provides a kind of adjustable compact SCR mixer, including the cylinder shell with first end and the second end opposite with the first end, the first end of cylinder shell is provided with gas inlet, the second end of cylinder shell is provided with gas outlet, nozzle is installed on the cylinder wall of cylinder shell, cyclone pipe is installed in the inner chamber of cylinder shell by sealing plate, and the lower edge of the flow guide baffle is installed on the sealing plate, to form flow guide passage between the flow guide baffle and cyclone pipe, the gas entering from the gas inlet enters the cyclone pipe through the flow guide passage, at least one valve assembly is provided on the flow guide baffle and / or sealing plate, for bypass airflow.The utility model also provides corresponding post-processing system.Back pressure is low, mixing effect is good, and crystallization prevention performance is excellent.

Description

Technical Field

[0001] This utility model belongs to the field of exhaust gas treatment technology, specifically relating to an adjustable compact SCR mixer and after-treatment system. Background Technology

[0002] As domestic diesel vehicle emission regulations continue to be upgraded, stricter requirements are being placed on vehicle exhaust after-treatment systems and their core component, the mixer. As a key component of the after-treatment system, the performance of the mixer directly affects NOx emissions.

[0003] Current technical challenges of post-processing systems:

[0004] High back pressure in the aftertreatment system leads to poor engine fuel economy;

[0005] Urea crystallization within the mixer;

[0006] The mixing efficiency of urea with waste gas is low, resulting in low De-NOx conversion efficiency.

[0007] Therefore, it is necessary to optimize and upgrade the mixer and its post-processing system. Utility Model Content

[0008] To address the shortcomings of existing technologies, this invention provides an adjustable compact SCR mixer and post-processing system with low back pressure, good mixing effect, and excellent anti-crystallization performance.

[0009] To address the aforementioned technical problems, a first aspect of this utility model provides an adjustable compact SCR mixer, characterized by comprising a cylindrical housing having a first end and a second end opposite to the first end. The first end of the cylindrical housing is provided with an air inlet, and the second end of the cylindrical housing is provided with an air outlet. A nozzle is mounted on the cylindrical wall of the cylindrical housing. A swirl tube is mounted within the inner cavity of the cylindrical housing via a sealing plate. A flow guide baffle extends from one side of the air inlet around the swirl tube to the other side of the air inlet, with the lower edge of the flow guide baffle mounted on the sealing plate to form a flow guide channel between the flow guide baffle and the swirl tube. Gas entering from the air inlet enters the swirl tube through the flow guide channel. At least one valve assembly is provided on the flow guide baffle and / or the sealing plate for bypassing airflow.

[0010] Preferably, the valve assembly includes a bracket, a rotating shaft assembly, and a valve cover plate. The valve cover plate is rotatably and repositionably mounted on the bracket via the rotating shaft assembly, and the valve opening can be automatically opened and closed by rotating the valve cover plate.

[0011] Preferably, the rotating shaft assembly includes a Z-shaped spring, the helical portion of which is mounted on the rotating shaft of the rotating shaft assembly, and the Z-shaped portion of which abuts against the valve cover plate to automatically reset the valve cover plate.

[0012] Preferably, a first partition plate is installed at the first end of the cylindrical shell, and the air inlet is located on the first partition plate. A second partition plate is installed at the second end of the cylindrical shell, and the air outlet is located on the second partition plate. A first opening is provided in the cylindrical wall of the cylindrical shell for installing the nozzle. A second opening is provided in the sealing plate. The swirling tube passes through the second opening and is installed on the sealing plate, dividing the swirling tube into an upper tube and a lower tube by the sealing plate. The upper opening of the upper tube corresponds to the first opening. Both the upper and lower tube walls are provided with openings. The flow guide baffle is arranged around the upper pipe body on the sealing plate, so that a first cavity is formed between the first partition, the cylindrical wall of the cylindrical shell, the flow guide baffle, and the sealing plate. The air inlet of the first partition is the inlet for gas to flow into the first cavity, and the opening of the upper pipe body is the outlet for gas to flow out of the first cavity. A second cavity is formed between the first partition, the cylindrical wall of the cylindrical shell, the sealing plate, the flow guide baffle, and the second partition. The opening of the lower pipe body and the lower pipe opening of the lower pipe body are the inlets for gas to flow into the second cavity, and the air outlet of the second partition is the outlet for gas to flow out of the second cavity.

[0013] Preferably, a flow guide plate is provided inside the inner cavity of the cylindrical shell, and the flow guide plate is provided corresponding to the lower pipe opening of the lower pipe body; there is an outlet gap between the lower pipe opening of the lower pipe body and the flow guide plate for gas to flow out.

[0014] Preferably, the air inlet is located on the upper side of the first partition, such that the gas entering from the air inlet swirls around one side of the swirling tube to the outlet of the first cavity; the air outlet is located in the central region of the second partition.

[0015] Preferably, the first baffle is provided with an arc-shaped protrusion extending along the axial direction of the cyclone tube. The arc-shaped protrusion is away from the cyclone tube protrusion and matches the tube wall of the cyclone tube, so that there is an arc-shaped gap between the arc-shaped protrusion and the tube wall of the cyclone tube to form a vortex.

[0016] Preferably, the opening in the upper tube body includes a first opening and a second opening, the first opening is located above the second opening, the first opening is disposed in the upper part of the upper tube body, and a blade is disposed in part of the second opening;

[0017] The longitudinal axis of the cyclone tube is at a preset angle to the longitudinal axis of the cylindrical shell, and the preset angle is 60° to 120°.

[0018] Preferably, the flow guide baffle is arc-shaped, and the flow guide baffle is provided with several arc-shaped flow guide grooves.

[0019] The second aspect of this utility model provides a post-treatment system, characterized in that it includes the aforementioned adjustable compact SCR mixer, the first end of which is sequentially connected to a DPF and a DOC, the second end of which is connected to an SCR or an ASC, the DOC being provided with a gas inlet, the SCR or ASC being provided with a gas outlet, and the longitudinal axis of the adjustable compact SCR mixer coinciding with the longitudinal axis of the post-treatment system.

[0020] The adjustable compact SCR mixer and post-treatment system of this invention can automatically open the valve under specific pressure to directly bypass a portion of the high-temperature gas, thereby achieving the effects of controlling the overall back pressure, reducing / eliminating crystallization, and enhancing the reduction reaction capacity with nitrogen oxides. Attached Figure Description

[0021] Figure 1 This is an exploded view of the adjustable compact SCR mixer of this utility model.

[0022] Figure 2 This is a first-view schematic diagram illustrating the working principle of the adjustable compact SCR mixer of this utility model.

[0023] Figure 3 This is a second-view schematic diagram illustrating the working principle of the adjustable compact SCR mixer of this utility model.

[0024] Figure 4 This is a schematic diagram of the flow guide baffle and sealing plate in the adjustable compact SCR mixer of this utility model.

[0025] Figure 5 This is a third-person perspective schematic diagram illustrating the working principle of the adjustable compact SCR mixer of this utility model.

[0026] Figure 6 This is a schematic diagram of the adjustable compact SCR mixer of this utility model.

[0027] Figure 7 This is an exploded view of the valve assembly in the adjustable compact SCR mixer of this utility model.

[0028] Figure 8This is a schematic diagram of the valve assembly in the adjustable compact SCR mixer of this utility model. Detailed Implementation

[0029] To make the technical problem solved by this utility model clearer, the present utility model is further described below with reference to embodiments and accompanying drawings. The specific embodiments described herein are only for explaining the present utility model and are not intended to limit the present utility model.

[0030] This utility model provides a post-treatment system, wherein the post-treatment system includes the aforementioned adjustable compact SCR mixer, the first end of which is sequentially connected to DPF and DOC, the second end of which is connected to SCR or ASC, the DOC being provided with a gas inlet, and the SCR or ASC being provided with a gas outlet, the longitudinal axis of the adjustable compact SCR mixer coinciding with the longitudinal axis of the post-treatment system, that is, the post-treatment system as a whole is cylindrical.

[0031] The DPF, DOC, and adjustable compact SCR mixer / SCR can be connected via flanges, clamps, welding, etc., to form a cylindrical internal cavity. Specifically, the DPF can be designed to be detachable. The DOC (Diesel Oxidation Catalyst) is a diesel engine oxidation catalyst, the DPF (Diesel Particulate Filter) is a diesel particulate filter, the SCR (Selective Catalytic Reduction) is a selective catalytic reduction catalyst, and the ASC (Ammonia Slip Catalyst) is an ammonia oxidation catalyst. All components—DOC, DPF, SCR, and ASC—contain catalyst supports.

[0032] The exhaust gas enters the aftertreatment system through the intake assembly, and then passes through DOC, DPF, and finally enters the adjustable compact SCR mixer. It mixes with the reducing agent injected by the nozzle inside the adjustable compact SCR mixer, and then enters the SCR for catalytic reduction reaction. Finally, the exhaust gas that meets the requirements is discharged through the exhaust assembly.

[0033] like Figures 1 to 8The image shows an embodiment of the adjustable compact SCR mixer of this utility model. The compact mixer allows for adjustable back pressure, adjustable ammonia mixing uniformity, and adjustable fluid flow. The adjustable compact SCR mixer includes a cylindrical shell 5 having a first end and a second end opposite to the first end. The first end of the cylindrical shell 5 has an air inlet 101, and the second end has an air outlet 801. A nozzle is mounted on the cylindrical wall of the cylindrical shell 5. The cylindrical wall of the cylindrical shell 5 has a first opening for mounting the nozzle, which can be installed through the first opening of the mounting base 7.

[0034] A swirl tube is installed inside the cylindrical housing 5 via a sealing plate 6. A flow guide baffle 4 extends from one side of the air inlet 101 around the swirl tube to the other side of the air inlet 101, with the lower edge of the flow guide baffle 4 mounted on the sealing plate 6 to form a flow guide channel between the flow guide baffle 4 and the swirl tube. Gas entering from the air inlet 101 enters the swirl tube through the flow guide channel. At least one valve assembly 10 is provided on the flow guide baffle 4 and / or the sealing plate 6 for bypassing airflow. The valve assembly is configured to open automatically under a preset pressure, allowing some gas to bypass through the valve's inner orifice, thus regulating the airflow distribution. Valve plate assemblies can be placed on the flow guide baffle or the sealing plate, and there can be one or more of them.

[0035] like Figure 7 and Figure 8 As shown, the valve assembly 10 includes a bracket 11, a rotating shaft assembly, and a valve cover plate 12. The valve cover plate 12 is rotatably and repositionably mounted on the bracket 11 via the rotating shaft assembly. Rotating the valve cover plate 12 automatically opens and closes the valve opening 401. The valve cover plate 12 is provided with a sealing buffer pad 13.

[0036] The rotating shaft assembly includes a U-shaped spring 14. The spiral portion of the U-shaped spring 14 is mounted on the rotating shaft 16 of the rotating shaft assembly. The U-shaped portion of the U-shaped spring 14 abuts against the valve cover plate 12 to automatically reset the valve cover plate 12. Both ends of the U-shaped spring 14 can be fixed in the bending plate groove on the side of the bracket. The U-shaped portion contacts and abuts against the upper surface of the valve cover plate. During rotation, the U-shaped portion moves on the valve cover plate.

[0037] The zigzag spring 14 has a spiral portion forming concentric spiral holes 201 and 202. The bracket 11 has concentric holes 203 and 205 on its bent plane. The rotating shaft assembly includes concentric holes 204 and 206 on the valve cover plate. The rotating shaft passes through the concentric holes 203, 204, 202, 201, 205, and 206 in sequence to realize the rotation function of the valve cover plate 12. A wire mesh washer 15 is provided between the rotating shaft and the concentric holes 203 and 205.

[0038] like Figures 1 to 6 As shown, a first partition plate 1 is installed at the first end of the cylindrical shell 5, and the air inlet 101 is located on the first partition plate 1. A second partition plate 8 is installed at the second end of the cylindrical shell 5, and the air outlet 801 is located on the second partition plate 8. A first opening is provided in the cylindrical wall of the cylindrical shell 5 for installing the nozzle. A second opening 601 is provided in the sealing plate 6. The swirling tube passes through the second opening 601 and is installed on the sealing plate 6. The sealing plate 6 divides the swirling tube into an upper tube body 2 and a lower tube. The upper pipe of the upper pipe body 2 corresponds to the first opening. Both the pipe walls of the upper pipe body 2 and the lower pipe body 3 have openings. The guide baffle 4 surrounds the upper pipe body 2 and is mounted on the sealing plate 6, forming a first cavity 501 between the first partition 1, the cylindrical wall of the cylindrical shell 5, the guide baffle 4, and the sealing plate 6. The air inlet 101 of the first partition 1 is the inlet for gas to flow into the first cavity 501, and the opening of the upper pipe body 2 is the outlet for gas to flow out of the first cavity 501. This first cavity 501 is annular, allowing the exhaust gas to form a swirling flow after entering the first cavity through the air inlet. The interior of the swirling pipe and the nozzle seat form a third cavity 502. The exhaust gas swirling in the first cavity 501 enters the third cavity 502 through the opening in the pipe wall of the upper pipe body and mixes with the reducing agent sprayed by the nozzle in the third cavity 502.

[0039] The first partition 1, the cylindrical wall of the cylindrical shell 5, the sealing plate 6, the guide baffle 4, and the second partition 8 form a second cavity 503. The opening and lower pipe port of the lower pipe 3 are the inlets for gas to flow into the second cavity 503, and the outlet 801 of the second partition 8 is the outlet for gas to flow out of the second cavity 503. The gas mixed in the third cavity 502 enters the second cavity 503 through the lower pipe port and the side wall opening, undergoes further mixing in the second cavity 503, and flows out through the outlet.

[0040] like Figure 1 As shown, a flow guide plate 9 is provided inside the inner cavity of the cylindrical shell 5, and the flow guide plate 9 is provided corresponding to the lower pipe opening of the lower pipe body 3; there is an outlet gap between the lower pipe opening of the lower pipe body 3 and the flow guide plate 9 for gas to flow out, and holes can also be opened on the pipe wall of the lower pipe body 3 to allow gas to flow out.

[0041] like Figure 5As shown, the air inlet 101 is located on the upper side of the first partition 1, so that the gas entering from the air inlet 101 swirls around one side of the swirling tube and flows to the outlet of the first cavity 501; the air outlet 801 is located in the central region of the second partition 8. Based on the side opening on the first partition, which facilitates the formation of swirling flow, this invention does not limit the shape of the air inlet. In addition to the air outlet 801, other openings can also be provided on the second partition 8.

[0042] The first partition 1 is provided with an arc-shaped protrusion extending along the axial direction of the cyclone tube. The arc-shaped protrusion is away from the cyclone tube protrusion and matches the tube wall of the cyclone tube, so that there is an arc-shaped gap between the arc-shaped protrusion and the tube wall of the cyclone tube, making the first cavity an annular cavity for forming swirl.

[0043] like Figure 1 As shown, the upper tube 2 has a first opening and a second opening. The first opening is located above the second opening and is situated on the upper part of the upper tube 2. A blade is partially installed in the second opening. The blade can face inwards or outwards.

[0044] The longitudinal axis of the cyclone tube forms a predetermined angle with the longitudinal axis of the cylindrical shell 5, wherein the predetermined angle is 60° to 120°, preferably around 90°. The cyclone tube can be a circular tube, an elliptical tube, or other similar shapes.

[0045] like Figure 1 and Figure 3 As shown, the flow guide baffle 4 is arc-shaped and has several arc-shaped flow guide grooves to facilitate the guidance of swirling gas.

[0046] This utility model discloses an adjustable compact SCR mixer and post-treatment system. Under specific pressures, it can automatically open valves to directly bypass a portion of the high-temperature gas, achieving the effect of controlling the overall back pressure. Under specific high loads, opening the valves allows the high-temperature gas flow to surround the outside of the mixing tube wall, heating the mixer and effectively reducing or eliminating crystallization. Valve on / off control can effectively reduce crystallization, generating more ammonia to reduce nitrogen oxides. Furthermore, by controlling different valve opening degrees, the gas flow and ammonia distribution at the outlet can be adjusted, effectively improving the uniformity of gas and ammonia before SCR (Selective Catalytic Reduction), thereby enhancing the reduction reaction capacity with nitrogen oxides.

[0047] The above descriptions are specific embodiments of this utility model and do not constitute a limitation on the scope of protection of this utility model. Any modifications and variations made to the technical concept of this utility model should be included within the scope of protection of this utility model.

Claims

1. An adjustable compact SCR mixer, characterized in that, The device includes a cylindrical shell having a first end and a second end opposite to the first end. The first end of the cylindrical shell is provided with an air inlet, and the second end of the cylindrical shell is provided with an air outlet. A nozzle is installed on the cylindrical wall of the cylindrical shell. A swirling tube is installed in the inner cavity of the cylindrical shell through a sealing plate. A flow guide baffle extends from one side of the air inlet around the swirling tube to the other side of the air inlet, and the lower edge of the flow guide baffle is installed on the sealing plate to form a flow guide channel between the flow guide baffle and the swirling tube. Gas entering from the air inlet enters the swirling tube through the flow guide channel. At least one valve assembly is provided on the flow guide baffle and / or the sealing plate for bypassing the airflow.

2. The adjustable compact SCR mixer according to claim 1, characterized in that, The valve assembly includes a bracket, a rotating shaft assembly, and a valve cover plate. The valve cover plate is rotatably and repositionably mounted on the bracket via the rotating shaft assembly. Rotating the valve cover plate automatically opens and closes the valve opening.

3. The adjustable compact SCR mixer according to claim 2, characterized in that, The rotating shaft assembly includes a Z-shaped spring, the spiral portion of which is mounted on the rotating shaft of the rotating shaft assembly, and the Z-shaped portion of which abuts against the valve cover plate to automatically reset the valve cover plate.

4. The adjustable compact SCR mixer according to claim 1, characterized in that, A first partition plate is installed at the first end of the cylindrical shell, and the air inlet is located on the first partition plate. A second partition plate is installed at the second end of the cylindrical shell, and the air outlet is located on the second partition plate. A first opening is provided in the cylindrical wall of the cylindrical shell for installing the nozzle. A second opening is provided in the sealing plate, and the swirling tube passes through the second opening and is installed on the sealing plate. The sealing plate divides the swirling tube into an upper tube and a lower tube. The upper opening of the upper tube corresponds to the first opening. Both the upper and lower tube walls are provided with openings. A flow guide baffle is disposed around the upper tube body on the sealing plate, thereby forming a first cavity between the first partition, the cylindrical wall of the cylindrical shell, the flow guide baffle, and the sealing plate. The air inlet of the first partition is the inlet for gas to flow into the first cavity, and the opening of the upper tube body is the outlet for gas to flow out of the first cavity. A second cavity is formed between the first partition, the cylindrical wall of the cylindrical shell, the sealing plate, the flow guide baffle, and the second partition. The opening of the lower tube body and the lower tube opening of the lower tube body are the inlets for gas to flow into the second cavity, and the air outlet of the second partition is the outlet for gas to flow out of the second cavity.

5. The adjustable compact SCR mixer according to claim 4, characterized in that, A flow guide plate is provided inside the inner cavity of the cylindrical shell, and the flow guide plate is provided corresponding to the lower pipe opening of the lower pipe body; there is an outlet gap between the lower pipe opening of the lower pipe body and the flow guide plate for gas to flow out.

6. The adjustable compact SCR mixer according to claim 4, characterized in that, The air inlet is located on the upper side of the first partition, so that the gas entering from the air inlet swirls around one side of the swirling tube to the outlet of the first cavity; the air outlet is located in the central region of the second partition.

7. The adjustable compact SCR mixer according to claim 4, characterized in that, The first baffle plate is provided with an arc-shaped protrusion extending along the axial direction of the cyclone tube. The arc-shaped protrusion is away from the cyclone tube protrusion and matches the tube wall of the cyclone tube, so that there is an arc-shaped gap between the arc-shaped protrusion and the tube wall of the cyclone tube to form a cyclone.

8. The adjustable compact SCR mixer according to claim 4, characterized in that, The opening in the upper tube body includes a first opening and a second opening. The first opening is located above the second opening and is disposed on the upper part of the upper tube body. A blade is disposed in part of the second opening. The longitudinal axis of the cyclone tube is at a preset angle to the longitudinal axis of the cylindrical shell, and the preset angle is 60° to 120°.

9. The adjustable compact SCR mixer according to claim 1, characterized in that, The flow guide baffle is arc-shaped and has several arc-shaped flow guide grooves.

10. A post-processing system, characterized in that, The system includes an adjustable compact SCR mixer as described in any one of claims 1 to 9, wherein a first end of the adjustable compact SCR mixer is sequentially connected to a DPF and a DOC, a second end of the adjustable compact SCR mixer is connected to an SCR or an ASC, the DOC is provided with a gas inlet, the SCR or ASC is provided with a gas outlet, and the longitudinal axis of the adjustable compact SCR mixer coincides with the longitudinal axis of the aftertreatment system.

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