CN211950637U - Mixer and exhaust gas treatment unit - Google Patents

Abstract

The utility model provides a mixer for mixing tail gas and tail gas treatment liquid. The mixer includes a housing including a bottom plate, a top plate opposite the bottom plate, and side walls extending between the top and bottom plates. The bottom, top and side walls define a mixing chamber. The bottom plate is provided with an exhaust gas inlet communicating with the mixing chamber, and the side wall is provided with an exhaust gas treatment liquid inlet communicating with the mixing chamber. The mixer also includes an exhaust treatment fluid nozzle connected to the exhaust treatment fluid inlet for spraying the exhaust treatment fluid into the mixing chamber along an injection path. The orthographic projection of the intersection of the jet path and the casing on the bottom plate does not overlap the exhaust gas inlet. The utility model also provides a tail gas treatment unit including the mixer. According to the present invention, droplets of the exhaust gas treatment liquid that are not evaporated by the exhaust gas can be prevented from flowing out of the mixer from the exhaust gas inlet.

Description

Mixer and exhaust gas treatment unit

technical field

The utility model relates to the treatment of engine exhaust gas, in particular to a mixer for mixing the exhaust gas with an exhaust gas treatment liquid and an exhaust gas treatment unit including the mixer.

Background technique

When the engine is running, it produces exhaust gas with a high content of nitrogen oxides, which cannot be directly discharged into the atmosphere, but needs to be treated by an exhaust gas treatment system before being discharged into the atmosphere. For diesel vehicles, an effective technology for treating the exhaust gas emitted by diesel engines is to use selective catalytic reduction (SCR) methods to reduce the content of nitrogen oxides in the exhaust gas emitted by the engine. The SCR method treats the exhaust by using an exhaust treatment fluid (usually an aqueous urea solution) in the exhaust treatment unit of a selective catalytic reduction aftertreatment system. Such an exhaust gas treatment unit usually includes a mixer having an exhaust gas treatment fluid inlet on the side wall and an exhaust gas inlet on the bottom plate. When the exhaust gas enters the mixer through the exhaust gas inlet, the exhaust gas treatment liquid is sprayed into the mixer in a controlled manner in a jet flow through the exhaust gas treatment liquid nozzle. In the mixer, the exhaust gas treatment liquid is mixed with the hot exhaust gas to form a vortex, which evaporates and undergoes pyrolysis and hydrolysis reactions to produce ammonia gas (NH ₃ ), which then reacts with the exhaust gas under the catalytic action of the catalyst.

In an exhaust gas treatment unit, the mixer may be positioned with the base plate oriented substantially parallel to the horizontal, as required by the application. In this case, if the exhaust gas treatment liquid injected into the mixer is not sufficiently evaporated by the exhaust gas, it accumulates to form droplets. Due to the above orientation of the mixer, droplets of exhaust gas treatment fluid will drip from the mixer through the exhaust gas inlet on the bottom plate into a device located below it, such as a diesel particulate filter (DPF), where it crystallizes As a result, the device is blocked (for example, the pores of the DPF are blocked), resulting in performance degradation or even failure of the exhaust gas treatment unit.

Thus, there is an urgent need to improve existing mixers.

Utility model content

An object of the present invention is to provide a mixer for mixing exhaust gas and exhaust gas treatment liquid. Such a mixer, when positioned with the base plate oriented substantially parallel to the horizontal plane, is capable of preventing droplets of off-gas treatment liquid from flowing out of the mixer from the off-gas inlet without being vaporized by the off-gas.

According to an aspect of the present invention, there is provided a mixer for mixing exhaust gas and exhaust gas treatment liquid, the mixer includes a casing, and the casing includes:

bottom plate;

a top plate opposite said bottom plate; and

a side wall extending between the top panel and the bottom panel;

The bottom plate, the top plate and the side walls define a mixing chamber, the bottom plate is provided with an exhaust gas inlet communicating with the mixing chamber, and the side wall is provided with an exhaust gas treatment communicating with the mixing chamber liquid inlet;

The mixer further includes an exhaust treatment liquid nozzle connected to the exhaust treatment liquid inlet, and the exhaust treatment liquid nozzle is configured to spray the exhaust treatment liquid into the mixing chamber along a spray path;

It is characterized in that, the orthographic projection of the intersection of the injection path and the casing on the bottom plate does not overlap the exhaust gas inlet.

Preferably, the intersection of the spray path and the housing is on the side wall.

Preferably, the housing further comprises one or more baffles extending from the side wall and/or the floor within the mixing chamber, and the spray path intersects the housing at the on one or more baffles.

Preferably, a blocking portion is formed on the inner surface of the bottom plate facing the mixing chamber, so as to confine the unevaporated exhaust gas treatment liquid in the mixing chamber.

Preferably, the blocking portion is in at least one of the following forms:

a bead or flange extending toward the interior of the mixing chamber at the edge of the base plate that defines the exhaust gas inlet;

a ramp or raised portion formed at least partially on the inner surface of the base plate; and

The bottom plate is at least partially inclined at an angle relative to the side wall.

Preferably, when used to mix the exhaust gas with the exhaust gas treatment fluid, the mixer is arranged in an orientation with the bottom plate substantially parallel to the horizontal plane.

Preferably, the mixer further includes an intermediate plate disposed in the mixing chamber between the exhaust gas treatment liquid inlet and the top plate, the intermediate plate defining an intermediate plate opening to partition the mixing chamber into a first chamber and a second chamber that communicate with each other.

Preferably, the intermediate plate opening is located directly above the intersection of the spray path and the housing.

Preferably, the mixer further includes at least one deflector disposed between the bottom plate and the intermediate plate within the first chamber, the at least one deflector being configured to allow exhaust gas to escape from entering The space through which the mixer is mixed with the exhaust gas treatment liquid is further reduced.

Preferably, the at least one deflector includes a first deflector and a second deflector, the first deflector and the second deflector extending facing each other on both sides of the spray path , without overlapping the jet path.

According to another aspect of the present invention, an exhaust gas treatment unit is provided, characterized in that, the exhaust gas treatment unit includes an oxidation catalyst, an SCR catalyst and the aforementioned mixer.

The mixer according to the present invention is used in an engine, especially a diesel engine exhaust gas aftertreatment system, to mix the exhaust gas with the exhaust gas treatment fluid. Such a mixer is configured to prevent droplets of tail gas treatment fluid that have not been evaporated from the tail gas from flowing out of the mixer from the tail gas inlet when positioned in position with the base plate substantially parallel to the horizontal plane, thereby protecting those located below the mixer The device is protected from the droplets of the tail gas treatment liquid and ensures the reliable operation of the tail gas treatment unit. In addition, such a mixer can also facilitate the evaporation of the exhaust gas treatment liquid injected into the mixer. The present application also relates to an exhaust gas treatment unit comprising such a mixer, which can be used to treat the exhaust gas emitted by an engine, especially a diesel engine, in order to reduce the content of nitrogen oxides in the exhaust gas.

Description of drawings

1 is a partial cross-sectional view of a typical exhaust gas treatment unit used in an engine, especially a diesel engine exhaust gas aftertreatment system;

FIG. 2A is a schematic bottom side perspective view of a conventional mixer used in the exhaust gas treatment unit shown in FIG. 1 , and FIG. 2B is a partial cross-sectional view of the mixer, wherein the mixer is cut away to show its internal structure ;

3A to 3E schematically illustrate a mixer according to a first embodiment of the present invention, wherein FIGS. 3A and 3B are a bottom perspective view and a top perspective view of the mixer, respectively, and FIG. 3C is a A partial cross-sectional view of the mixer, FIG. 3D is a cross-sectional view of the mixer taken along its longitudinal axis, and FIG. 3E is a cross-sectional view of the mixer taken along line A-A in FIG. 3D;

4A schematically depicts the injection path of the exhaust gas treatment fluid nozzle in the conventional mixer shown in FIGS. 2A to 2B , and FIGS. 4B and 4C schematically depicts the injection path of the exhaust gas treatment liquid nozzle in the mixer shown in FIGS. 3A to 3E . The injection path of the exhaust gas treatment fluid nozzle;

5A to 5E schematically show a mixer according to a second embodiment of the present invention, wherein FIG. 5A and FIG. 5B are partial cross-sectional views of the mixer, respectively, and FIG. 5C is the mixer along the mixer. A cross-sectional view taken along the longitudinal axis, Figure 5D is a cross-sectional view of the mixer taken along line B-B in Figure 5C, and Figure 5E is a cross-sectional view of the mixer taken along line C-C in Figure 5C ;as well as

FIGS. 6A to 6E schematically show a mixer according to a third embodiment of the present invention, wherein FIGS. 6A and 6B are partial cross-sectional views of the mixer, respectively, and FIG. 6C is a view of the mixer along the mixer. A cross-sectional view taken along the longitudinal axis, Figure 6D is a cross-sectional view of the mixer taken along line D-D in Figure 6C, and Figure 6E is a cross-sectional view of the mixer taken along line E-E in Figure 6C .

Detailed ways

The preferred embodiments of the present invention will be described in detail below with reference to examples. It should be understood by those skilled in the art that these exemplary embodiments are not meant to form any limitation to the present invention.

As used herein, the term "substantially parallel to the horizontal" means within 20°, within 15°, within 10°, within 5°, within 3°, within 2°, within 1°, or within 1° of the ground or horizontal plane. The ground or horizontal plane is substantially parallel. The term "vertical" refers to a direction perpendicular to the ground or horizontal, and the term "substantially parallel to the vertical" refers to within 20°, within 15°, within 10°, within 5°, 3° from vertical within 2°, within 1°, or substantially parallel to vertical.

As shown in FIG. 1, a typical exhaust gas treatment unit 1 for an engine, especially a diesel engine exhaust gas after-treatment system, comprises a housing 3 having an intake port 5 opened in the bottom part and an exhaust port 7 opened in the top part, And has a longitudinal axis 9 extending in the longitudinal direction of the housing 3 . The exhaust gas treatment unit 1 is generally positioned in a diesel exhaust aftertreatment system with an orientation of the longitudinal axis 9 substantially parallel to the vertical direction. The intake port 5 is in communication with the exhaust gas of the diesel engine for receiving the exhaust gas emitted by the diesel engine, and the exhaust port 7 is used for discharging the treated exhaust gas out of the exhaust gas treatment unit 1 . The exhaust gas treatment unit 1 may further include a diesel oxidation catalyst (DOC) 11 , a diesel particulate filter (DPF) 13 , a mixer 15 and an SCR catalyst 17 which are sequentially arranged in the casing 3 along the exhaust gas flow direction. With continued reference to Figure 1, the mixer 15 is positioned within the housing 3 with the base plate oriented substantially parallel to the horizontal plane. While the exhaust gas flows through the mixer 15 , the exhaust gas treatment liquid is injected into the mixer 15 in a jet flow manner through an exhaust gas treatment liquid nozzle (not shown in FIG. 1 ). In the mixer 15 , the exhaust gas treatment liquid is mixed with the hot exhaust gas to form a vortex, so as to evaporate and undergo pyrolysis and hydrolysis reactions to produce ammonia gas (NH ₃ ), which is then catalyzed by the SCR catalyst 17 . reaction.

It should be understood that the components included in the exhaust gas treatment unit 1 shown in FIG. 1 are only exemplary and not limitative. In some other embodiments, the SCR and DPF may be set selectively or combined. It should also be understood that, in addition to the exhaust gas treatment unit 1 shown in FIG. 1 , the diesel engine exhaust gas after-treatment system may also include a storage tank for storing an exhaust gas treatment liquid such as an aqueous urea solution, a nozzle for injecting the exhaust gas treatment liquid, and a nozzle connected to the storage tank. The conveying device for conveying the exhaust gas treatment fluid between the tank and the nozzle, various types of sensors, etc., these components cooperate to realize the function of the diesel exhaust after-treatment system.

Figures 2A, 2B and 4A schematically show a conventional mixer 15 in the exhaust gas treatment unit 1 of Figure 1 . The mixer 15 includes a generally cylindrical housing including a top plate (not shown), a bottom plate 21 opposite the top plate, and side walls 23 extending between the top and bottom plates 21 . The top and bottom plates 21 extend substantially parallel to each other. The top plate, bottom plate 21 and side walls 23 together define a mixing chamber 24 . The side wall 23 is provided with an exhaust gas treatment liquid inlet 27 communicating with the mixing chamber 24 , and the bottom plate 21 is provided with an exhaust gas inlet 31 communicating with the mixing chamber 24 . The mixer 15 also includes an exhaust treatment fluid nozzle 25 ( FIG. 4A ) connected to the exhaust treatment fluid inlet 27 for injecting the exhaust treatment fluid into the mixing chamber 24 along an injection path. When the exhaust gas enters the mixing chamber 24 through the exhaust gas inlet 31 , the exhaust gas treatment liquid is sprayed into the mixing chamber 24 in a jet flow manner through the exhaust gas treatment liquid nozzle 25 . The housing also includes one or more baffles 29 extending from the bottom plate 21 within the mixing chamber 24 . The baffle 29 intersects with the injection path of the exhaust gas treatment fluid nozzle 25, so that the jet of the exhaust gas treatment fluid impinges on the baffle 29 (as shown in FIG. 4A ), so that the exhaust gas treatment fluid becomes smaller droplets for the benefit of the exhaust gas of evaporation. The baffle 29 is provided just above the exhaust gas inlet 31 . That is to say, the orthographic projection of the intersection of the injection path of the exhaust gas treatment liquid nozzle 25 and the baffle plate 29 on the bottom plate 21 overlaps or even coincides with the exhaust gas inlet 31 .

As mentioned above, the mixer 15 is positioned in the exhaust gas treatment unit 1 with the base plate 21 oriented substantially parallel to the horizontal plane. In this case, if the exhaust gas treatment liquid injected into the mixing chamber 24 is not sufficiently evaporated by the exhaust gas, the exhaust gas treatment liquid may accumulate on the baffle plate 29 to form droplets. Due to gravity, droplets of the exhaust gas treatment liquid will (as indicated by arrows 33) drop from the mixer 15 through the exhaust gas inlet 31 into the DPF 13 located below the mixer 15, thereby crystallizing in the DPF 13 and thus blocking the pores of the DPF 13, As a result, the performance of the exhaust gas treatment unit 1 is degraded or even malfunctions.

In order to solve the above-mentioned technical problems, the present application proposes a new type of mixer, which is configured to prevent the exhaust gas treatment fluid that is not evaporated from the exhaust gas when it is placed in place with the bottom plate substantially parallel to the horizontal plane. The droplets flow out of the mixer from the exhaust gas inlet.

Figures 3A to 3E and Figures 4B and 4C schematically illustrate a mixer 101 according to a first embodiment of the present invention. As shown in FIGS. 3A-3C , the mixer 101 includes a generally cylindrical housing including a bottom plate 105 , a top plate 107 opposite the bottom plate 105 , and side walls 109 extending between the bottom plate 105 and the top plate 107 . Bottom plate 105 and top plate 107 may extend substantially parallel to each other. The top plate 107 , the bottom plate 105 and the side walls 109 together define a mixing chamber 108 . The side wall 109 is provided with an exhaust gas treatment liquid inlet 111 communicating with the mixing chamber 108 , the bottom plate 105 is provided with an exhaust gas inlet 113 communicating with the mixing chamber 108 , and the top plate 107 is provided with an exhaust gas outlet 114 communicating with the mixing chamber 108 . The mixer 101 also includes an exhaust treatment fluid nozzle 125 (shown schematically in FIGS. 4B and 4C ) connected to the exhaust treatment fluid inlet 111 for injecting the exhaust treatment fluid along the injection path into the mixing chamber 108 liquid. When the exhaust gas enters the mixing chamber 108 through the exhaust gas inlet 113 , the exhaust gas treatment liquid is sprayed into the mixing chamber 108 in a jet flow through the exhaust gas treatment liquid nozzle 125 . In the mixing chamber 108 , the exhaust gas treatment liquid is mixed with the hot exhaust gas to form a vortex, thereby vaporizing and undergoing pyrolysis and hydrolysis reactions, producing ammonia gas (NH ₃ ), which is then discharged from the exhaust gas outlet 115 from the mixing chamber 108 with the exhaust gas. .

Turning to FIGS. 3D and 3E and FIGS. 4B and 4C , unlike the conventional mixer 15 shown in FIGS. 2A and 2B , the intersection of the injection path of the exhaust gas treatment fluid nozzle 125 of the mixer 101 and the housing is on the bottom plate 105 The orthographic projection of , does not overlap the exhaust gas inlet 113 . This prevents the droplets of the exhaust gas treatment liquid on the shell that are not evaporated by the exhaust gas from flowing out of the mixer 101 directly through the exhaust gas inlet 113, but is blocked by the bottom plate 105, thus preventing the droplets of the exhaust gas treatment liquid that are not evaporated by the exhaust gas. The mixer 101 flows out of the exhaust gas inlet 113 . The droplets of exhaust gas treatment liquid that are trapped on the bottom plate 105 can then be evaporated by the hot exhaust gas. In one example, the intersection of the injection path of the exhaust gas treatment fluid nozzle 125 and the housing may be on the side wall 109 . In another example, the housing may also include one or more baffles extending from the sidewall 109 and/or the floor 105 within the mixing chamber 108, which are designed to cause the exhaust gas treatment fluid to become more Small droplets are used to facilitate the evaporation of exhaust gas, such as the baffles shown in Figure 2A and Figure 2B. In this case, the intersection of the injection path of the exhaust gas treatment fluid nozzle 125 and the housing may be on such a baffle.

Turning now to FIGS. 4A to 4C , the dotted lines in each view represent the injection paths of the exhaust gas treatment fluid nozzle 25 of the mixer 15 and the exhaust gas treatment fluid nozzle 125 of the mixer 101 , respectively, and the circles schematically represent the injection paths and the housing the location of the intersection. As discussed above, in the mixer 15 , the orthographic projection of the intersection of the injection path of the exhaust gas treatment liquid nozzle 25 and the baffle 29 on the bottom plate 21 overlaps or even coincides with the exhaust gas inlet 31 . In one example of the mixer 101 , the intersection of the injection path of the exhaust gas treatment fluid nozzle 125 and the housing may be on the side wall 109 . This makes the orthographic projection of the intersection of the injection path of the exhaust gas treatment liquid nozzle 125 and the casing on the bottom plate 105 not overlapped with the exhaust gas inlet 113 , thereby preventing the droplets of the exhaust gas treatment liquid that are not evaporated by the exhaust gas from flowing out of the mixer from the exhaust gas inlet 113 101.

In addition, this configuration also makes the distance of the jet of the exhaust gas treatment fluid longer from entering the mixer 101 to the point of impact. Since the jet of the exhaust gas treatment liquid is roughly in the shape of a cone, the longer the distance, the larger the impact area of the jet flow, which promotes the exhaust gas treatment liquid to be more dispersed into small droplets, thereby promoting the heating of the exhaust gas treatment liquid. Exhaust gas evaporates. In one example, as shown in FIG. 4C , the injection paths of the exhaust treatment fluid nozzles 125 may be substantially along diametrically opposed directions within the mixing chamber 108 . In other examples, as shown in FIG. 4B , the injection paths of the exhaust treatment fluid nozzles 125 may also be offset with respect to diametrically opposite directions within the mixing chamber 108 .

Although the above configuration helps prevent droplets of the exhaust gas treatment liquid that are not evaporated by the exhaust gas from flowing out of the mixer 101 from the exhaust gas inlet 113 and promotes the evaporation of the exhaust gas treatment liquid by the exhaust gas, since the mixer 101 is installed with the bottom plate 105 substantially parallel to the horizontal plane Oriented, when the droplets of the tail gas treatment liquid that are not evaporated by the tail gas flow on the bottom plate 105 and accumulate, the droplets of the tail gas treatment liquid may still flow out of the mixer 101 from the tail gas inlet 113 .

In order to further prevent the droplets of the exhaust gas treatment liquid from flowing out of the mixer 101 from the exhaust gas inlet 113 , a blocking part may be formed on the inner surface of the bottom plate 105 of the mixer 101 facing the mixing chamber 108 to restrict the unevaporated exhaust gas treatment liquid within the mixing chamber 108 . The blocking portion can be implemented in various forms. In the example shown in FIGS. 3A-3E , a bead or flange 115 extending toward the interior of the mixing chamber 108 may be formed at the edge of the bottom plate 105 of the mixer 101 that defines the exhaust gas inlet 113 . In another example, the inner surface of the bottom plate of the mixer facing the mixing chamber may be at least partially formed with ramps or protrusions. In yet another example, the bottom plate of the mixer may be inclined at least partially at an angle relative to the side walls of the mixer. It should be understood that the blocking portion can also be in any other form, as long as it can confine the droplets of the exhaust gas treatment fluid within the mixing chamber to prevent the droplets of the exhaust gas treatment fluid accumulated on the bottom plate from flowing out of the mixer from the exhaust gas inlet.

5A to 5E schematically illustrate a mixer 201 according to a second embodiment of the present invention. The difference between the mixer 201 and the mixer 101 is that the mixer 201 further includes an intermediate plate 217 disposed between the exhaust gas treatment liquid inlet 211 and the top plate 207 in the mixing chamber 208 . The middle plate 217 may extend substantially parallel to the top plate 207 or the bottom plate 205 . The intermediate plate 217 defines an intermediate plate opening 219 (FIGS. 5C and 5E) to separate the mixing chamber 208 into a first chamber 208a and a second chamber 208b that communicate with each other. As shown in FIG. 5C , the orthographic projection of the intermediate plate opening 219 on the bottom plate 205 may not overlap the exhaust gas inlet 213 to form a serpentine gas flow path in the mixing chamber 208 to promote the mixing of the exhaust gas and the exhaust gas treatment liquid. In one example, the intermediate plate opening 219 may be located directly above the intersection of the spray path and the housing. The mixer 201 also includes an exhaust treatment fluid nozzle (not shown) connected to the exhaust treatment fluid inlet 211 for spraying the exhaust treatment fluid into the mixing chamber 208a along an injection path. When the exhaust gas enters the first chamber 208a through the exhaust gas inlet 213, the exhaust gas treatment liquid is sprayed into the first chamber 208a in a jet flow manner through the exhaust gas treatment liquid nozzle. The jetting path intersects the casing at the first chamber 208a, so that the jet of the exhaust treatment liquid impinges on the casing, thereby making the exhaust treatment liquid into smaller droplets to facilitate evaporation by the hot exhaust gas. Compared with the mixer 101, due to the existence of the intermediate plate 217 in the mixer 201, the space through which the exhaust gas passes from entering the mixer 201 to mixing with the exhaust gas treatment liquid is smaller (the volume of the first chamber 208a is smaller than that of the mixing chamber 108). volume), which makes the heat of the exhaust gas in the mixing chamber 208 more concentrated, thereby promoting the evaporation of the exhaust gas treatment liquid. This improves the evaporation efficiency of the exhaust gas treatment liquid and thus the working efficiency of the mixer 201 .

6A to 6E schematically illustrate a mixer 301 according to a third embodiment of the present invention. The difference between the mixer 301 and the mixer 201 is that the mixer 301 further includes at least one baffle plate arranged between the bottom plate 305 and the intermediate plate 317 . The at least one deflector is configured to further reduce the space through which the exhaust gas passes from entering the mixer 301 from the exhaust gas inlet 313 to being mixed with the exhaust gas treatment liquid. Two baffles are shown in FIGS. 6A to 6E : a first baffle 321 and a second baffle 323 . The first deflector 321 and the second deflector 323 extend facing each other on both sides of the injection path of the exhaust gas treatment liquid nozzle of the mixer 301 without overlapping the injection path. This configuration of the first deflector 319 and the second deflector 323 further reduces the space through which the exhaust gas passes from entering the mixer 301 to being mixed with the exhaust gas treatment liquid. This can further concentrate the heat of the exhaust gas in the first chamber 308a, thereby further promoting the evaporation of the exhaust gas treatment liquid. This further improves the evaporation efficiency of the exhaust gas treatment liquid and thus the working efficiency of the mixer 301 . It should be understood that more or fewer baffles may also be provided.

As mentioned above, the mixer according to the invention is used in an engine, especially a diesel exhaust gas treatment unit, to mix the exhaust gas with the exhaust gas treatment fluid. Such a mixer is configured to prevent droplets of off-gas treatment fluid that have not been vaporized from the off-gas from flowing out of the mixer from the off-gas inlet when the bottom plate is oriented substantially parallel to the horizontal plane, thereby protecting equipment located below the mixer from It is affected by the droplets of the exhaust gas treatment liquid and ensures the reliable operation of the exhaust gas aftertreatment system. In addition, such a mixer can also facilitate the evaporation of the exhaust gas treatment liquid injected into the mixer. The present application also relates to an exhaust gas treatment unit comprising such a mixer, which can be used to treat exhaust gas emitted by a diesel engine in order to reduce the content of nitrogen oxides in the exhaust gas emitted by the diesel engine.

The present invention has been described in detail above with reference to the specific embodiments. Obviously, the above descriptions and the embodiments shown in the accompanying drawings should be construed as exemplary rather than limiting of the present invention. For those skilled in the art, various variations or modifications can be made without departing from the spirit of the present invention, and these variations or modifications do not depart from the scope of the present invention.

Claims (10)

1. A mixer (101, 201, 301) for mixing exhaust gas with an exhaust gas treatment liquid, the mixer (101, 201, 301) comprising a housing, the housing comprising:

a backplane (105, 205, 305);

a top plate (107, 207) opposite the bottom plate (105, 205, 305); and

a sidewall (109) extending between the top plate (107, 207) and the bottom plate (105, 205, 305);

the bottom plate (105, 205, 305), the top plate (107, 207) and the side wall (109) define a mixing chamber (108, 208), the bottom plate (105, 205, 305) is provided with an exhaust gas inlet (113, 213, 313) communicated with the mixing chamber (108, 208), and the side wall (109) is provided with an exhaust gas treatment liquid inlet (111, 211) communicated with the mixing chamber (108, 208);

the mixer (101, 201, 301) further comprises an off-gas treatment liquid nozzle (125) connected to the off-gas treatment liquid inlet (111, 211), the off-gas treatment liquid nozzle (125) for spraying off-gas treatment liquid into the mixing chamber (108, 208) along a spray path;

characterized in that the orthographic projection of the intersection of the spray path and the housing on the floor (105, 205, 305) does not overlap the exhaust gas inlet (113, 213, 313).

2. The mixer of claim 1, wherein:

the intersection of the spray path and the housing is on the sidewall (109); or

The housing further comprises one or more baffles extending from the side wall (109) and/or the floor (105, 205, 305) within the mixing chamber (108, 208), and the intersection of the spray path and the housing is on the one or more baffles.

3. The mixer according to claim 1, characterized in that the inner surface of the floor (105, 205, 305) facing the mixing chamber (108, 208) is formed with a barrier to confine the non-evaporated off-gas treatment liquid within the mixing chamber (108, 208).

4. A mixer according to claim 3, wherein the barrier is in the form of at least one of:

a bead or flange (115) extending towards the interior of the mixing chamber (108, 208) at the edge of the floor (105, 205, 305) bounding the exhaust gas inlet (113, 213, 313);

a ramp or protrusion formed at least partially on the inner surface of the floor (105, 205, 305); and

the floor (105, 205, 305) is at least partially inclined at an angle relative to the side wall (109).

5. The mixer according to claim 1, wherein the mixer (101, 201, 301) is arranged in an orientation in which the floor (105, 205, 305) is substantially parallel to a horizontal plane when used for mixing exhaust gas with an exhaust gas treatment liquid.

6. The mixer of any of claims 1 to 5, wherein the mixer (201, 301) further comprises an intermediate plate (217, 317) disposed within the mixing chamber (208) between the off-gas treatment fluid inlet (211) and the top plate (207), the intermediate plate (217, 317) defining an intermediate plate opening (219, 319) to divide the mixing chamber (208) into a first chamber (208a, 308a) and a second chamber (208b) in communication with each other.

7. The mixer of claim 6, wherein the intermediate plate openings (219, 319) are located directly above the intersection of the spray path and the housing.

8. The mixer according to claim 6, wherein the mixer (301) further comprises at least one baffle plate disposed between the bottom plate (305) and the intermediate plate (317) within the first chamber (308a), the at least one baffle plate being configured to further reduce the space through which the exhaust gas passes from entering the mixer (301) to mixing with the exhaust gas treatment liquid.

9. The mixer of claim 8, wherein the at least one baffle comprises a first baffle (321) and a second baffle (323), the first baffle (321) and the second baffle (323) extending facing each other on both sides of the spray path without overlapping the spray path.

10. An exhaust gas treatment unit, characterized in that the exhaust gas treatment unit comprises an oxidation catalyst, an SCR catalyst and a mixer according to any one of claims 1-9.

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