Tail gas mixer

Abstract

The tail gas mixer comprises a mixing pipe, steel wool and a vent pipe, a tail gas inlet is formed in the side wall of the mixing pipe, the steel wool is installed in the mixing pipe, and the vent pipe is installed on the steel wool and penetrates through the two opposite end faces of the steel wool in the height direction of the mixing pipe. Tail gas can enter the mixing pipe through the tail gas inlet and then flow to the outlet of the mixing pipe through the vent pipe and the steel wool. The tail gas mixer provided by the utility model can improve the air permeability of the steel wool, so that the back pressure of the mixing pipe is reduced.

Description

Technical Field

[0001] The present application relates to the technical field of tail gas treatment, and in particular to a tail gas mixer. Background Art

[0002] As emissions regulations continue to tighten, limits on nitrogen oxide emissions are becoming increasingly stringent. After-treatment products primarily use SCR (Selective Catalytic Reduction) units to treat nitrogen oxides in exhaust gas. Ammonia produced by urea hydrolysis reacts with nitrogen oxides over a catalyst to produce nitrogen. To improve conversion efficiency, a mixer is typically installed at the front end of the SCR to thoroughly mix the urea solution spray with the exhaust gas.

[0003] Conventional exhaust gas mixers typically consist of a housing and a mixing tube mounted within the housing. The mixing tube is equipped with a urea nozzle for spraying urea solution into the mixing tube. Exhaust gas enters the mixing tube from the housing, mixes with the urea solution within the mixing tube, and then exits the mixing tube. To ensure a more uniform exhaust flow, steel wool is typically placed at the outlet end of the mixing tube to balance the flow. However, because steel wool is too fine and has poor air permeability, it can lead to excessive backpressure in the mixing tube. Utility Model Content

[0004] Based on this, it is necessary to provide an exhaust gas mixer to improve the air permeability of steel wool, thereby reducing the back pressure of the mixing tube.

[0005] An exhaust gas mixer includes a mixing tube, steel wool and a breathable tube. An exhaust gas inlet is provided on the side wall of the mixing tube. The steel wool is installed in the mixing tube. The breathable tube is installed on the steel wool and penetrates the two opposite end faces of the steel wool along the height direction of the mixing tube. The exhaust gas can enter the inner cavity of the mixing tube through the exhaust gas inlet and then flow to the outlet of the mixing tube through the breathable tube and the steel wool.

[0006] In one embodiment, the number of ventilation tubes is configured to be multiple, and the multiple ventilation tubes are spaced apart on the steel wool; the diameter of each ventilation tube is between 8 mm and 10 mm, the total cross-sectional area of ​​the multiple ventilation tubes is S1, the cross-sectional area of ​​the steel wool is S2, and 12%≤S1 / S2≤18%.

[0007] In one embodiment, a flow guide is provided in the air permeable tube. The flow guide is configured in a plate shape, and the plate is twisted and extended around the axial direction of the air permeable tube.

[0008] In one embodiment, the exhaust gas mixer also includes a nozzle structure, which is installed at the end of the mixing tube away from the steel wool and is used to spray urea solution into the mixing tube. The mixing tube is provided with a plurality of fins, one end of each fin is connected to the mixing tube, and the other end extends in a direction away from the mixing tube, and the plurality of fins are distributed at intervals along the circumference of the mixing tube, and the exhaust gas inlet includes a plurality of through holes, which are arranged in a one-to-one correspondence with the fins; wherein, the exhaust gas can enter the interior of the mixing tube through the corresponding plurality of through holes under the disturbance action of the plurality of fins, and be mixed with the urea solution inside the mixing tube and circulate in a rotation.

[0009] In one embodiment, each fin is tilted outward relative to a corresponding through hole, and an angle β is formed between each fin and the corresponding through hole, and 25°≤β≤35°.

[0010] In one embodiment, the air tube is arranged parallel to or tilted relative to the axis of the mixing tube, wherein when the air tube is tilted relative to the axis of the mixing tube, the tilt direction of the air tube is consistent with the rotation flow direction of the exhaust gas inside the mixing tube.

[0011] In one embodiment, the number of the air tubes is configured to be multiple, and the multiple air tubes form at least two air tube groups, each air tube group includes multiple air tubes distributed at intervals along the circumference of the mixing tube, and at least two air tubes are arranged along the radial direction of the mixing tube.

[0012] In one embodiment, when the air permeable tube is tilted relative to the axis of the mixing tube, the tilt angle of the air permeable tube relative to the axis of the mixing tube is α, and 0°<α≤30°.

[0013] In one embodiment, the air vent tube is configured as a metal tube, and the air vent tube is fixed to the steel wool by welding, bonding, or clamping.

[0014] In one embodiment, the exhaust gas mixer also includes an outer tube, an inner tube, a front baffle, a rear baffle and a diverter plate. The outer tube is sleeved on the outer periphery of the inner tube, and the outer tube and the inner tube are spaced apart and enclosed to form a channel. The front baffle and the rear baffle are respectively located at the two ends of the inner tube, and the front baffle is used to close the channel, and the rear baffle is used to seal the inner tube. The mixing tube is installed in the inner tube, and the mixing tube is provided with one end of steel wool extending into the channel and connecting the channel. The diverter plate is installed in the channel, wherein the exhaust gas enters the mixing tube from the inner tube through the exhaust inlet, then enters the channel from the mixing tube, and is diverted and discharged through the diverter plate.

[0015] Compared with the prior art, the exhaust gas mixer provided in this application is equipped with an air vent tube, which can increase the air permeability of the steel wool, making it convenient for the exhaust gas to be discharged from the mixing tube through the air vent tube and the steel wool, thereby effectively reducing the back pressure of the mixing tube. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the conventional technology, the following briefly introduces the drawings required for use in the embodiments or the conventional technology descriptions. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0017] Figure 1 An axonometric view of an exhaust gas mixer in one of the embodiments provided in this application;

[0018] Figure 2 This is a schematic diagram of an explosion of an exhaust gas mixer in one of the embodiments provided in this application;

[0019] Figure 3 A cross-sectional view of an exhaust gas mixer in one of the embodiments provided in this application;

[0020] Figure 4 A top view of a mixing tube in one of the embodiments provided in this application;

[0021] Figure 5 An axonometric view of the assembly of steel wool and a breathable tube in one of the embodiments provided in this application;

[0022] Figure 6 A top view of the assembly of steel wool and a breathable tube in one of the embodiments provided in this application;

[0023] Figure 7 for Figure 6 Cross-sectional view at AA;

[0024] Figure 8 This is an axonometric view of the flow guide member in one of the embodiments provided in this application.

[0025] Figure numerals: 100, exhaust gas mixer; 10, shell; 11, outer tube; 12, inner tube; 13, front baffle; 14, rear baffle; 15, channel; 20, mixing tube; 21, fin; 22, through hole; 30, nozzle structure; 31, cover plate; 32, nozzle seat; 41, steel wool; 42, air pipe; 420, air pipe group; 421, guide member; 50, diverter plate. DETAILED DESCRIPTION

[0026] To make the above-mentioned objects, features, and advantages of the present application more clearly understood, the specific embodiments of the present application are described in detail below with reference to the accompanying drawings. The following description sets forth many specific details to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways than those described herein, and those skilled in the art can make similar improvements without violating the scope of the present application. Therefore, the present application is not limited to the specific embodiments disclosed below.

[0027] It should be noted that when a component is referred to as being "fixed to" or "disposed on" another component, it may be directly on the other component or there may be a central component. When a component is considered to be "connected to" another component, it may be directly connected to the other component or there may be a central component at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in the specification of this application are for illustrative purposes only and do not represent the only implementation method.

[0028] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of such features. Throughout the description of this application, "plurality" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0029] In this application, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it can mean that the first feature is directly in contact with the second feature, or the first feature and the second feature are indirectly in contact through an intermediary. Furthermore, when a first feature is "above," "above," or "above" a second feature, it can mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is higher in level than the second feature. When a first feature is "below," "below," or "below" a second feature, it can mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is lower in level than the second feature.

[0030] Unless otherwise defined, all technical and scientific terms used in the specification of this application have the same meaning as commonly understood by those skilled in the art to which this application belongs. The terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used in the specification of this application includes any and all combinations of one or more of the relevant listed items.

[0031] See also Figures 1 to 3The present application provides an exhaust gas mixer 100, which includes a shell 10, a mixing tube 20, a nozzle structure 30, steel wool 41 and an air pipe 42. The mixing tube 20 is installed in the shell 10, the nozzle structure 30 is installed at one end of the mixing tube 20 and is used to spray urea solution into the mixing tube 20, the steel wool 41 is installed in the mixing tube 20, the air pipe 42 is installed in the steel wool 41 and passes through the two opposite end faces of the steel wool 41 along the height direction of the mixing tube 20, and an exhaust gas inlet is opened on the side wall of the mixing tube 20; wherein, the exhaust gas enters the inner cavity of the mixing tube 20 from the shell 10 through the exhaust gas inlet, and is mixed with the urea solution in the mixing tube 20, and then flows to the outlet of the mixing tube 20 through the air pipe 42 and the steel wool 41. By providing the air vent tube 42 , the air vent tube 42 can increase the air permeability of the steel wool 41 , making it easier for the exhaust gas to be discharged from the mixing tube 20 through the air vent tube 42 and the steel wool 41 , thereby effectively reducing the back pressure of the mixing tube 20 .

[0032] The number of the ventilation tubes 42 is configured to be multiple, and the multiple ventilation tubes 42 are spaced apart on the steel wool 41. In this way, the ventilation performance of each part of the steel wool 41 is relatively uniform. Further, the multiple ventilation tubes 42 are evenly spaced apart on the steel wool 41.

[0033] The sum of the cross-sectional areas of the multiple air vents 42 is S1, the cross-sectional area of ​​the steel wool 41 is S2, and 12% ≤ S1 / S2 ≤ 18%. It is understandable that if S1 / S2 is too large, the exhaust gas will tend to pass directly through the air vents 42 and be directly discharged from the mixing tube 20. This will cause the steel wool 41 to lose its flow-balancing effect on the exhaust gas; if S1 / S2 is too small, it will be difficult for the air vents 42 to increase the air permeability of the steel wool 41. By setting 12% ≤ S1 / S2 ≤ 18%, the air permeability of the steel wool 41 can be increased while ensuring that the steel wool 41 balances the flow of the exhaust gas. For example, the value of S1 / S2 can be 12%, 13%, 14%, 15.5%, 17%, 18%, etc. The value of S1 / S2 can be selected according to actual needs, as long as it is within the above range.

[0034] The diameter of each of the air tubes 42 is between 8 mm and 10 mm. It is understood that if the diameter of each of the air tubes 42 is too large, the exhaust gas will tend to pass directly through the air tube 42, and the steel wool 41 will not be able to fully utilize its flow balancing effect on the exhaust gas. If the diameter of each of the air tubes 42 is too small, it will be difficult to increase the air permeability of the steel wool 41 and the processing difficulty of the air tube 42 will increase. For example, the diameter of the air tube 42 can be 8 mm, 8.5 mm, 9 mm, or 10 mm.

[0035] The wall thickness of each air tube 42 is between 0.2 mm and 0.4 mm. It is understood that the thicker the wall thickness of the air tube 42, the greater the structural strength of the air tube 42. However, this also results in the wall of the air tube 42 occupying a larger area on the cross-section of the steel wool 41. For example, the wall thickness of each air tube 42 can be 0.2 mm, 0.3 mm, or 0.4 mm.

[0036] The air tube 42 is configured as a metal tube and is welded to the steel wool 41. Alternatively, the air tube 42 can be configured as a stainless steel tube. The air tube 42 and the steel wool 41 are first fixed together and then brazed. This not only ensures a secure connection between the air tube 42 and the steel wool 41, but also improves the structural strength of the steel wool 41. Of course, the air tube 42 and the steel wool 41 can also be fixed by adhesive bonding or clamping.

[0037] See also Figure 8 Optionally, a flow guide 421 is provided within the air vent tube 42. The flow guide 421 is configured as a plate and twists and extends axially around the air vent tube 42. The flow guide 421 is used to guide the exhaust gas through the air vent tube 42 and reduce flow resistance during exhaust gas circulation. Of course, the flow guide 421 can also be configured to extend helically along the axial direction of the air vent tube 42.

[0038] like Figure 2 and Figure 3 As shown, the mixing tube 20 is provided with a plurality of fins 21, each of which is connected to the mixing tube 20 at one end and extends away from the mixing tube 20 at the other end. Furthermore, the plurality of fins 21 are spaced apart along the circumference of the mixing tube, and the exhaust gas inlet includes a plurality of through-holes 22, which are arranged in a one-to-one correspondence with the fins 21. In this way, the exhaust gas can enter the interior of the mixing tube 20 through the corresponding plurality of through-holes 22 under the disturbing effect of the plurality of fins 21, and is fully mixed with the urea solution sprayed from the nozzle structure 30 inside the mixing tube 20, thereby swirling and circulating.

[0039] Specifically, if Figure 4 As shown, each fin 21 is tilted outward relative to a corresponding through-hole 22, forming an angle β between each fin 21 and the corresponding through-hole 22, with 25°≤β≤35°. It is understood that if β is too small, the exhaust gas will have increased resistance to entering the mixing tube 20, while if β is too large, the fin 21 will have a poor effect on the exhaust gas's disturbance, making it difficult for the exhaust gas to rotate and circulate within the mixing tube 20. For example, the angle β can be 25°, 27°, 28°, 30°, 30.5°, 35°, etc., as long as it is within the above range, and is not listed here.

[0040] like Figure 3As shown, the air tube 42 is arranged parallel to the axis of the mixing tube 20, so as to facilitate the positioning and installation between the air tube 42 and the steel wool 41.

[0041] like Figures 5 to 7 As shown, the vent tube 42 can also be arranged at an angle relative to the axis of the mixing tube 20, with the inclination of the vent tube 42 being consistent with the rotational flow direction of the exhaust gas within the mixing tube 20. In this way, the exhaust gas mixed with the urea solution and circulated downward along the axial direction of the mixing tube 20 can directly enter the vent tube 42, thereby reducing the resistance of the exhaust gas passing through the mixing tube 20.

[0042] Among them, such as Figure 7 As shown, the inclination angle of the vent pipe 42 relative to the axis of the mixing tube 20 is α, and 0°<α≤30°. It is understood that if α is too large, it will be difficult for exhaust gas to enter the vent pipe 42. For example, the value of α can be 10°, 24°, 30°, etc.

[0043] For example, in one embodiment, Figure 5 As shown, the number of the air tubes 42 is configured to be multiple, and the multiple air tubes 42 form at least two air tube groups 420, each air tube group 420 includes multiple air tubes 42 distributed at intervals along the circumference of the mixing tube 20, and at least two air tubes 42 are arranged along the radial direction of the mixing tube 20.

[0044] See also Figure 2 The housing 10 includes an outer tube 11, an inner tube 12, a front baffle 13, a rear baffle 14, and a diverter plate 50. The outer tube 11 is sleeved around the outer periphery of the inner tube 12, and the outer tube 11 and the inner tube 12 are spaced apart and enclose a channel 15. The front baffle 13 and the rear baffle 14 are located at both ends of the inner tube 12, with the front baffle 13 used to close the channel 15, and the rear baffle 14 used to cover the inner tube 12. The mixing tube 20 is mounted on the inner tube 12, and one end of the mixing tube 20, provided with steel wool 41, extends into and communicates with the channel 15. The diverter plate 50 is mounted within the channel 15. Exhaust gas enters the mixing tube 20 from the inner tube 12 through the exhaust inlet, then enters the channel 15 from the mixing tube 20, and is diverted by the diverter plate 50 and discharged.

[0045] The front baffle 13 is annular, with its outer ring welded to the inner wall of the outer tube 11, and its inner ring abutting the outer wall of the inner tube 12. The rear baffle 14 is welded to the inner tube 12. The surface of the rear baffle 14 facing the inner tube 12 is configured as an arc surface. One end of the diverter plate 50 is welded to the inner wall of the outer tube 11, and the other end is welded to the outer wall of the inner tube 12. The diverter plate 50 divides the exhaust gas into left and right sides. The nozzle structure 30 includes a cover plate 31 and a nozzle holder 32. The nozzle holder 32 is fixedly mounted on the cover plate 31 and is mounted to the mixing tube 20 through the cover plate 31.

[0046] The cross-sectional area of ​​the channel 15 is approximately equal to that of the inner tube 12 , so that the cross-sectional areas of the inlet and outlet sides of the exhaust mixer 100 are approximately the same, thereby reducing the overall back pressure of the exhaust mixer 100 .

[0047] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0048] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, all of which fall within the scope of protection of the present application. Therefore, the scope of patent protection for the present application shall be determined by the appended claims.

Claims

1. An exhaust gas mixer, characterized in that: The exhaust gas mixer comprises a mixing tube (20), steel wool (41) and a ventilation tube (42); an exhaust gas inlet is provided on a side wall of the mixing tube (20); the steel wool (41) is installed in the mixing tube (20); and the ventilation tube (42) is installed on the steel wool (41) and passes through two opposite end surfaces of the steel wool (41) along the height of the mixing tube (20); The exhaust gas can enter the inner cavity of the mixing tube (20) through the exhaust gas inlet, and then flow to the outlet of the mixing tube (20) through the air vent (42) and the steel wool (41).

2. The exhaust gas mixer according to claim 1, characterized in that The number of the ventilation tubes (42) is multiple, and the multiple ventilation tubes (42) are distributed at intervals on the steel wool (41); The diameter of each of the ventilation tubes (42) is between 8 mm and 10 mm, the total cross-sectional area of ​​the plurality of ventilation tubes (42) is S1, the cross-sectional area of ​​the steel wool (41) is S2, and 12%≤S1 / S2≤18%.

3. The exhaust gas mixer according to claim 1, characterized in that A flow guide (421) is provided in the air permeable tube (42). The flow guide (421) is configured in a plate shape, and the plate shape is twisted and extended around the axial direction of the air permeable tube (42).

4. The exhaust gas mixer according to claim 1, characterized in that The exhaust gas mixer further comprises a nozzle structure (30), wherein the nozzle structure (30) is mounted on an end of the mixing tube (20) away from the steel wool (41) and is used for spraying urea solution into the mixing tube (20); The mixing tube (20) is provided with a plurality of fins (21), one end of each fin (21) is connected to the mixing tube (20), and the other end extends in a direction away from the mixing tube (20), and the plurality of fins (21) are distributed at intervals along the circumference of the mixing tube, and the exhaust gas inlet includes a plurality of through holes (22), and the through holes (22) are arranged in a one-to-one correspondence with the fins (21); The exhaust gas can enter the interior of the mixing tube (20) through the corresponding plurality of through holes (22) under the disturbing action of the plurality of fins (21), and is mixed with the urea solution inside the mixing tube (20) and circulates in a rotating manner.

5. The exhaust gas mixer according to claim 4, characterized in that: Each of the fins (21) is tilted outward relative to a corresponding through hole (22), and an angle β is formed between each of the fins (21) and a corresponding through hole (22), and 25°≤β≤35°.

6. The exhaust gas mixer according to claim 4, characterized in that: The air vent tube (42) is arranged parallel to or tilted relative to the axis of the mixing tube (20), wherein when the air vent tube (42) is tilted relative to the axis of the mixing tube (20), the tilt direction of the air vent tube (42) is consistent with the rotation flow direction of the exhaust gas inside the mixing tube (20).

7. The exhaust gas mixer according to claim 6, characterized in that: The number of the air tubes (42) is configured to be multiple, and the multiple air tubes (42) form at least two air tube groups (420), each of the air tube groups (420) includes multiple air tubes (42) distributed at intervals along the circumference of the mixing tube (20), and at least two of the air tubes (42) are arranged along the radial direction of the mixing tube (20).

8. The exhaust gas mixer according to claim 6, characterized in that: When the air vent tube (42) is tilted relative to the axis of the mixing tube (20), the tilt angle of the air vent tube (42) relative to the axis of the mixing tube (20) is α, and 0°<α≤30°.

9. The exhaust gas mixer according to any one of claims 1 to 8, characterized in that: The air vent tube (42) is configured as a metal tube, and the air vent tube (42) and the steel wool (41) are fixed by welding, bonding, or clamping.

10. The exhaust gas mixer according to claim 1, characterized in that: The exhaust gas mixer further comprises an outer tube (11), an inner tube (12), a front baffle (13), a rear baffle (14) and a diverter plate (50), wherein the outer tube (11) is sleeved on the outer periphery of the inner tube (12), and the outer tube (11) and the inner tube (12) are spaced apart and enclosed to form a channel (15), the front baffle (13) and the rear baffle (14) are respectively located at two ends of the inner tube (12), and the front baffle (13) is used to close the channel (15), and the rear baffle (14) is used to cover the inner tube (12), the mixing tube (20) is installed on the inner tube (12), and one end of the mixing tube (20) provided with the steel wool (41) extends into the channel (15) and communicates with the channel (15), and the diverter plate (50) is installed in the channel (15); The exhaust gas enters the mixing tube (20) from the inner tube (12) through the exhaust gas inlet, then enters the channel (15) from the mixing tube (20), and is diverted by the diverter plate (50) and discharged.

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