A tail gas mixing device
By employing inclined evaporation plates and a flow guiding structure in the exhaust gas mixing device, the problem of uneven diffusion of urea solution was solved, achieving efficient mixing of urea and exhaust gas and full reaction of NOx, thus improving the exhaust gas treatment effect.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- HEFEI SHENZHOU CATALSIS PURIFIER CO LTD
- Filing Date
- 2025-09-04
- Publication Date
- 2026-06-16
AI Technical Summary
Diesel vehicle exhaust gases have localized high flow rates and speeds, and the diffusion range of urea atomization is limited, making it difficult for the urea solution to contact the exhaust gases evenly, resulting in some NOx not being fully reacted.
Design an exhaust gas mixing device, comprising an exhaust mixing pipe, a urea nozzle, a baffle plate, and a mixing cylinder. The mixing cylinder is equipped with inclined evaporation plates and a flow guiding structure to uniformly distribute the urea solution and improve the mixing efficiency of urea and exhaust gas through high-temperature evaporation and flow guiding.
It achieves uniform distribution and efficient evaporation of urea solution, improves the mixing effect of exhaust gas and urea, ensures full reaction of NOx, and enhances the thoroughness of exhaust gas treatment.
Smart Images
Figure CN224364004U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of diesel vehicle exhaust gas treatment technology, and in particular to an exhaust gas mixing device. Background Technology
[0002] Diesel vehicle exhaust treatment refers to the process of purifying the exhaust gases emitted by diesel engines to reduce the content of harmful substances. Diesel vehicle exhaust mainly contains pollutants such as particulate matter (PM), nitrogen oxides (NOx), carbon monoxide (CO), and hydrocarbons (HC). By installing exhaust treatment devices, such as diesel oxidation catalysts (DOC), particulate filters (DPF), and selective catalytic reduction systems (SCR), harmful substances in the exhaust gases are converted into harmless or less harmful substances through chemical reactions or physical filtration, thereby reducing pollution to the atmospheric environment and meeting increasingly stringent emission regulations.
[0003] In diesel vehicle exhaust treatment, selective catalytic reduction (SCR) technology is required. Urea solution is atomized through a nozzle and injected into the high-temperature exhaust gas, where it rapidly decomposes into ammonia (NH3) and carbon dioxide (CO2). The ammonia then reacts chemically with nitrogen oxides (NOx) in the exhaust gas on the surface of the SCR catalyst, reducing them to harmless nitrogen (N2) and water (H2O).
[0004] The shortcomings of the above-mentioned existing technical solutions are that, during use, there are situations where the local exhaust gas flow rate is large and the flow velocity is fast, the diffusion range of urea after atomization is limited, and the urea solution is difficult to fully diffuse into these areas, which makes it impossible for the urea solution to come into uniform contact with the exhaust gas, resulting in some NOx not being able to fully react with ammonia. Utility Model Content
[0005] This invention provides an exhaust gas mixing device that can solve the problems in the prior art where the exhaust gas flow rate is large and the flow velocity is fast, the diffusion range of urea after atomization is limited, and the urea solution is difficult to fully diffuse into these areas.
[0006] An exhaust gas mixing device includes an exhaust mixing pipe, on which a urea nozzle for spraying urea is fixedly installed. Inside the exhaust mixing pipe, a baffle plate is fixedly installed. On the baffle plate, a mixing cylinder corresponding to the outlet of the urea nozzle is provided. A conveying port for sending part of the exhaust gas to the outlet of the mixing cylinder is opened on the baffle plate.
[0007] As a further embodiment of this utility model: the mixing cylinder includes a cylinder wall fixedly connected to the baffle plate, and multiple sets of evaporation plates arranged parallel to each other are fixedly arranged inside the cylinder wall. Each set of evaporation plates is inclined relative to the axis of the cylinder wall, so that urea can be sprayed onto the surface of the multiple sets of evaporation plates.
[0008] As a further embodiment of this utility model, the cylinder wall is provided with a guide opening to facilitate the discharge of exhaust gas.
[0009] As a further embodiment of this utility model: the flow guiding opening is provided in two sets, and the output position of the conveying port corresponds to the position of the two sets of flow guiding openings.
[0010] As a further embodiment of this invention: each group of evaporating plates is provided with a flow-guiding concave surface in the middle, which is used to guide the exhaust gas and increase the surface area of the evaporating plates.
[0011] As a further aspect of this invention: there are gaps between the multiple sets of evaporating plates, and the horizontal heights of the multiple sets of evaporating plates are all different.
[0012] As a further embodiment of this utility model, the side of the mixing cylinder is provided with multiple sets of through holes to facilitate the discharge of exhaust gas.
[0013] As a further embodiment of this utility model: the folding plate includes two sets of fixedly connected plates, the two sets of plates are distributed vertically and completely block the exhaust mixing pipe, there is an included angle between the two sets of plates, the mixing cylinder is disposed on the upper plate, and the conveying port is located on the lower plate.
[0014] As a further embodiment of this utility model: a flow guiding component is fixedly provided on the conveying port, and the flow guiding direction of the flow guiding component corresponds to the lower end of the cylinder wall.
[0015] As a further embodiment of this utility model: the flow guiding component is a cylindrical structure fixedly connected to the folding plate.
[0016] The beneficial effects of this utility model are:
[0017] 1. In use, the inclined evaporator plates inside the exhaust mixing pipe fully receive the atomized urea solution sprayed from the urea nozzle, dispersing and evenly distributing it. Simultaneously, high temperature evaporates the urea, ensuring its complete integration into the exhaust gas. The exhaust gas output from the conveyor port impacts the area where the evaporator plates are located, further promoting mixing between the exhaust gas and the atomized urea solution. Furthermore, the guide openings on the cylinder wall and the through holes on the side of the mixing cylinder increase the exhaust gas flow rate and facilitate the absorption of ambient temperature, ensuring the evaporator plates maintain a consistently high temperature and guaranteeing efficient evaporation of the urea solution, resulting in more thorough exhaust gas treatment.
[0018] 2. When this utility model is used, a flow-guiding concave surface is set in the middle of each group of evaporating plates, which not only plays a good role in guiding the exhaust gas and making the exhaust gas flow more orderly, but also increases the surface area of the evaporating plates and improves the heat conduction and vaporization efficiency. Attached Figure Description
[0019] Figure 1A schematic diagram of the internal structure of the exhaust mixing pipe of the exhaust gas mixing device provided by this utility model;
[0020] Figure 2 A schematic diagram of the mixing cylinder structure of an exhaust gas mixing device provided by this utility model;
[0021] Figure 3 A schematic diagram of a folded plate structure for an exhaust gas mixing device provided by this utility model.
[0022] Explanation of reference numerals in the attached figures:
[0023] 1. Exhaust mixing pipe; 2. Baffle plate; 3. Urea nozzle; 4. Conveying port; 5. Mixing cylinder; 501. Cylinder wall; 502. Flow guide opening; 503. Evaporator plate; 5031. Flow guide concave surface; 504. Through hole. Detailed Implementation
[0024] The specific embodiments of this utility model are described in detail below, but it should be understood that the protection scope of this utility model is not limited to the specific embodiments.
[0025] like Figures 1 to 3 As shown in the figure, an exhaust gas mixing device provided in this embodiment of the present invention includes an exhaust mixing pipe 1, on which a urea nozzle 3 for spraying urea is fixedly installed. A baffle plate 2 is also fixedly installed inside the exhaust mixing pipe 1, and a mixing cylinder 5 corresponding to the output port of the urea nozzle 3 is provided on the baffle plate 2. At the same time, a conveying port 4 for sending part of the exhaust gas to the output port of the mixing cylinder 5 is opened on the baffle plate 2.
[0026] During operation, exhaust gas is supplied from one end of the exhaust mixing pipe 1 to the other. Since the mixing cylinder 5 is located inside the exhaust mixing pipe 1, its surrounding temperature is heated to 180℃-350℃. As the exhaust gas flows within the exhaust mixing pipe 1, it passes directly through the mixing cylinder 5. Simultaneously, the urea nozzle 3 sprays atomized urea solution directly into the mixing cylinder 5, thus achieving mixing of the exhaust gas and the atomized urea solution. Furthermore, the delivery port 4 outputs exhaust gas to the mixing cylinder 5. This design not only increases the flow rate of the exhaust mixing pipe 1 but also promotes more thorough mixing of the exhaust gas and the atomized urea solution.
[0027] Furthermore, the mixing cylinder 5 includes a cylinder wall 501 fixedly connected to the baffle 2. Inside the cylinder wall 501, multiple sets of mutually parallel evaporation plates 503 are fixedly arranged. Figure 2As shown, each set of evaporator plates 503 is inclined relative to the axis of the cylinder wall 501. This design allows the atomized urea solution sprayed from the urea nozzle 3 to be sprayed onto the surface of multiple sets of evaporator plates 503. The evaporator plates 503 can disperse the urea solution, making its distribution more uniform; they can also evaporate the urea solution they come into contact with by transferring high temperature, thereby allowing the urea to be fully mixed in the exhaust gas.
[0028] To increase the gas flow rate, a guide opening 502 is provided on the cylinder wall 501 to facilitate the exhaust gas discharge. There are gaps between multiple sets of evaporator plates 503, and the horizontal heights of the multiple sets of evaporator plates 503 are all different, such as... Figure 2 As shown, the urea solution is sprayed between multiple sets of evaporating plates 503, heated and vaporized in a high-temperature environment, and then conveyed out of the cylinder wall 501 by the exhaust gas conveying system. The guide openings 502 on the cylinder wall 501 can increase the flow rate of the exhaust gas inside the cylinder wall 501, making the exhaust gas flow smoother. At the same time, multiple sets of through holes 504 are also opened on the side of the mixing cylinder 5 to facilitate the exhaust gas discharge. These through holes 504 not only increase the flow rate, but also facilitate the absorption of ambient temperature by the mixing cylinder 5 and the evaporating plates 503, ensuring that the evaporating plates 503 can remain at a high temperature to better perform the function of evaporating the urea solution.
[0029] In another specific embodiment, two sets of guide openings 502 are symmetrically arranged (not shown in the figure), and the output position of the conveying port 4 corresponds to the position of these two sets of guide openings 502. In this structure, the cylinder wall 501 is responsible for guiding the exhaust gas and atomized urea solution. The exhaust gas and atomized urea solution are fully mixed between the evaporating plates 503. The exhaust gas output from the conveying port 4 impacts the area where the evaporating plates 503 are located, thereby enabling the exhaust gas output from the conveying port 4 to also mix with the atomized urea solution, further improving the mixing effect of the exhaust gas and urea solution.
[0030] Further optimizations can be made to the two embodiments described above. A flow-guiding concave surface 5031 can be provided in the middle of each group of evaporators 503. The flow-guiding concave surface 5031 can, on the one hand, guide the exhaust gas, making its flow between the evaporators 503 more orderly; on the other hand, it can increase the surface area of the evaporators 503, thereby improving the thermal conductivity and vaporization efficiency, providing a better mixing channel for the exhaust gas and atomized urea solution, allowing the urea solution to evaporate faster and mix thoroughly with the exhaust gas.
[0031] Furthermore, the baffle 2 includes two sets of fixedly connected plates, which are arranged vertically and completely block the exhaust mixing pipe 1. An angle exists between the two sets of plates, preferably greater than 60°. This design avoids occupying too much space and ensures sufficient space inside the exhaust mixing pipe 1 for the mixing and flow of exhaust gas and urea solution. Figure 3As shown. The mixing cylinder 5 is located on the upper side plate, and the conveying port 4 is located on the lower side plate.
[0032] To better guide the exhaust gas output from the conveying port 4, a flow guiding component is fixedly installed on the conveying port 4. The flow guiding direction of the component corresponds to the lower end of the cylinder wall 501 to ensure that the exhaust gas output from the conveying port 4 can accurately impact the area where the evaporator 503 is located, promoting the mixing of the exhaust gas and the urea solution. Specifically, the flow guiding component is a cylindrical structure fixedly connected to the baffle 2. Of course, other components that can achieve the flow guiding function still fall within the protection scope of this patent.
[0033] Working Principle: When the device is running, exhaust gas is continuously transported from one end of the exhaust mixing pipe 1 to the other. Since the mixing cylinder 5 is located inside the exhaust mixing pipe 1, the temperature near the mixing cylinder 5 is heated to 180℃-350℃ under high-temperature conditions. As the exhaust gas flows within the exhaust mixing pipe 1, it directly passes through the mixing cylinder 5. Simultaneously, the urea nozzle 3 precisely sprays atomized urea solution into the mixing cylinder 5. Multiple sets of evaporation plates 503 are installed inside the mixing cylinder 5, each set inclined relative to the axis of the cylinder wall 501. The urea solution is sprayed onto the surfaces of the multiple sets of evaporation plates 503. The evaporation plates 503 disperse the urea solution, making its distribution more uniform, and also evaporate the contacted urea solution by transferring high temperature, promoting thorough mixing of urea into the exhaust gas.
[0034] The conveying port 4 on the baffle plate 2 outputs exhaust gas to the lower end of the mixing cylinder 5. The exhaust gas output from the conveying port 4 impacts the area below the evaporator plate 503, mixing thoroughly with the atomized urea solution. Simultaneously, a guide concave surface 5031 is provided in the middle of each group of evaporator plates 503 to guide the exhaust gas, increase the surface area of the evaporator plate 503, improve the thermal conductivity and vaporization efficiency, and provide a better mixing channel for the exhaust gas and atomized urea solution. This allows the urea solution to evaporate more quickly and mix thoroughly with the exhaust gas, thereby effectively improving the mixing effect of the exhaust gas and urea solution.
[0035] To increase the gas flow rate, a flow guide opening 502 is provided on the cylinder wall 501, and multiple sets of through holes 504 are also provided on the side of the mixing cylinder 5. The urea solution is heated and vaporized between multiple sets of evaporating plates 503, and then sent out of the cylinder wall 501 under the action of the exhaust gas conveying. The flow guide opening 502 and the through holes 504 not only increase the exhaust gas flow rate, but also facilitate the absorption of ambient temperature by the mixing cylinder 5 and the evaporating plates 503, ensuring that the evaporating plates 503 are continuously kept at a high temperature, and better perform their function of evaporating the urea solution.
[0036] The above-disclosed embodiments are only a few specific examples of the present utility model. However, the embodiments of the present utility model are not limited thereto. Any changes that can be conceived by those skilled in the art should fall within the protection scope of the present utility model.
Claims
1. A tail gas mixing device, comprising an exhaust mixing pipe (1), wherein a urea nozzle (3) for spraying urea is fixedly disposed on the exhaust mixing pipe (1), characterized in that, The exhaust mixing pipe (1) is fixedly provided with a baffle plate (2), and a mixing cylinder (5) corresponding to the output port of the urea nozzle (3) is provided on the baffle plate (2). A conveying port (4) is provided on the baffle plate (2) for sending part of the exhaust gas to the output port of the mixing cylinder (5).
2. The exhaust gas mixing device as described in claim 1, characterized in that, The mixing cylinder (5) includes a cylinder wall (501) fixedly connected to the baffle (2). Multiple sets of evaporation plates (503) are fixedly arranged inside the cylinder wall (501) and are parallel to each other. Each set of evaporation plates (503) is inclined relative to the axis of the cylinder wall (501) so that urea can be sprayed on the surface of the multiple sets of evaporation plates (503).
3. The exhaust gas mixing device as described in claim 2, characterized in that, The cylinder wall (501) is provided with a guide opening (502) to facilitate the discharge of exhaust gas.
4. The exhaust gas mixing device as described in claim 3, characterized in that, The flow guide opening (502) is provided in two sets, and the output position of the conveying port (4) corresponds to the position of the two sets of flow guide openings (502).
5. The exhaust gas mixing device as described in claim 2, characterized in that, Each of the evaporator plates (503) has a flow-guiding concave surface (5031) in the middle, which is used to guide the exhaust gas and increase the surface area of the evaporator plate (503).
6. A tail gas mixing device as described in claim 2 or 5, characterized in that, There are gaps between the multiple sets of evaporation plates (503), and the horizontal heights of the multiple sets of evaporation plates (503) are different.
7. The exhaust gas mixing device as described in claim 6, characterized in that, The mixing cylinder (5) has multiple sets of through holes (504) on its side to facilitate the discharge of exhaust gas.
8. A tail gas mixing device as described in claim 2 or 4, characterized in that, The folding plate (2) includes two sets of fixedly connected plates. The two sets of plates are distributed vertically and completely block the exhaust mixing pipe (1). There is an angle between the two sets of plates. The mixing cylinder (5) is set on the upper plate and the conveying port (4) is located on the lower plate.
9. The exhaust gas mixing device as described in claim 1, characterized in that, A flow guiding component is fixedly installed on the conveying port (4), and the flow guiding direction of the flow guiding component corresponds to the lower end of the cylinder wall (501).
10. The exhaust gas mixing device as described in claim 9, characterized in that, The flow guiding component is a cylindrical structure that is fixedly connected to the folding plate (2).