End cover side feeding type mixer

Abstract

The invention provides an end cover side inlet type mixer, which comprises an end cover shell, and the end cover shell comprises an opening end and a side inlet end, a closed end; a first open pore and a second open pore of the barrel are respectively and independently formed in the barrel, the first open pore is used for mounting a nozzle, and the second open pore is an air inlet of the mixer; a rotational flow pipe, a first baffle and a second baffle are arranged in the inner cavity, and the rotational flow pipe is provided with a top pipe opening, a bottom pipe opening and a plurality of side openings formed in the side wall of the rotational flow pipe; the vertical projection of the second baffle covers the bottom pipe opening, an interval space exists between the second baffle and the position, corresponding to the inner wall of the bottom pipe opening, in the barrel, and gas entering from the second open hole heats the second baffle in the first cavity through the interval space. The end cover side inlet type mixer can be applied to a national sixth SCR system and a national seventh preceding-stage and post-stage SCR system, and is high in integration level, compact in space, low in back pressure, good in mixing effect and excellent in anti-crystallization performance.

Description

Technical Field

[0001] The invention belongs to the technical field of tail gas treatment, and in particular relates to an end cover side-inlet mixer. Background Art

[0002] With the continuous upgrading of domestic diesel vehicle emission regulations, more stringent requirements are put forward for automobile exhaust after-treatment systems and their core components, mixers. As a key component in the after-treatment system, the performance of the mixer directly affects NOx emissions.

[0003] The mixer needs to ensure that the exhaust gas and the reducing agent (such as urea aqueous solution) are fully mixed to improve the conversion efficiency of the SCR system. The mixer also needs to have good heat exchange performance to ensure that the urea aqueous solution is quickly vaporized and fully mixed with the exhaust gas during the injection process, which helps to improve the conversion efficiency of the SCR system and reduce urea consumption. Because the "National VI" standard has stricter emission restrictions under low temperature and low load conditions, and the injection volume increases, the risk of crystallization of the mixer increases. The generation of a large number of crystals will block the post-treatment channel, resulting in increased back pressure in the post-treatment system and insufficient vehicle power, and there is a risk of emissions exceeding regulatory limits.

[0004] With the upgrade of diesel engine regulations to National VII, the urea dual injection system is one of the important solutions. Compared with the National VI after-treatment, it is necessary to add urea injection at the inlet of the after-treatment, and it is necessary to add a pre-stage mixer and SCR catalyst, which poses a greater challenge to the boundary of the after-treatment system. The general technical solution uses a simple mixer in the pre-stage exhaust pipe, which has many disadvantages: unsatisfactory mixing effect, high back pressure, easy urea crystallization and other problems. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention provides an end cover side-entry mixer with high integration, compact space, low back pressure, good mixing effect and excellent anti-crystallization performance.

[0006] In order to solve the above technical problems, the present invention provides an end cover side-entry mixer, the main feature of which is that it includes an end cover housing, and the end cover housing includes:

[0007] An open end, wherein the open end is an air outlet of the mixer;

[0008] a closed end, opposite to the open end;

[0009] A barrel, located between the open end and the closed end, wherein the first opening and the second opening are independently arranged on the barrel, wherein the first opening is used to install the nozzle, and the second opening is the air inlet of the mixer;

[0010] Inner cavity, a swirl tube, a first baffle and a second baffle are arranged in the inner cavity. The swirl tube has a top pipe orifice, a bottom pipe orifice and several side openings formed in the side wall of the swirl tube;

[0011] The top pipe orifice is used to receive the reducing agent sprayed by the nozzle;

[0012] The first baffle is located between the open end and the swirl tube. The second baffle is installed on the bottom pipe orifice. A first cavity is formed between the first baffle, the cylinder body, the closed end and the second baffle. The second opening is the inlet for gas to flow into the first cavity, and the side opening is the outlet for gas to flow out of the first cavity. A second cavity is formed between the first baffle, the cylinder body, the open end and the second baffle. The bottom pipe orifice is the inlet for gas to flow into the second cavity, and the open end is the outlet for gas to flow out of the second cavity, so that the gas flowing in from the side opening and the reducing agent sprayed by the nozzle are mixed in the swirl tube and then flow out through the bottom pipe orifice and the open end in sequence;

[0013] The vertical projection of the second baffle covers the bottom pipe orifice, and there is a spaced space between the second baffle and the inner wall position of the cylinder body corresponding to the bottom pipe orifice. The gas entering from the second opening heats the second baffle through the spaced space in the first cavity.

[0014] Preferably, the second baffle has a mounting portion and an arc-shaped resisting portion. The arc-shaped resisting portion obliquely extends downward from a part of the mounting portion and extends to the inner wall of the cylinder body. The high-temperature gas entering from the second opening heats the arc-shaped resisting portion through the spaced space.

[0015] Preferably, the first baffle has an arc portion matching the swirl tube. The arc portion of the first baffle and the swirl tube form an arc-shaped space for forming a swirl.

[0016] Preferably, the side openings include several first side openings and several second side openings. The first side openings extend along the longitudinal axis of the swirl tube. The first side openings are spaced and distributed on the side surface of the swirl tube side wall facing away from the closed end. The longitudinal length of the first side openings is 0.1 to 0.99 times the longitudinal length of the swirl tube side wall; the second side openings are located above the first side openings, and the second side openings are spaced and distributed on the side wall of the swirl tube.

[0017] Preferably, at least one of the first side openings is provided with a blade, and the blade forms a preset angle with the side wall of the swirl tube.

[0018] Preferably, after the central axis of the second opening rotates 5° to 355° around the longitudinal axis of the cylinder body, it overlaps or is parallel to the central axis of the first opening.

[0019] Preferably, the longitudinal axis of the swirl tube forms a preset angle with the longitudinal axis of the cylinder body, and the preset angle is 60° to 120°.

[0020] Preferably, an air outlet baffle is arranged at the open end. The air outlet baffle has a first blocking portion and a second blocking portion located above the first blocking portion. The first blocking portion is used to completely block the area of the open end corresponding to the first blocking portion to block the bottom of the air outlet, and the second blocking portion is provided with a plurality of third openings, so that the second blocking portion partially blocks the area of the open end corresponding to the second blocking portion.

[0021] The end - cover side - inlet mixer of the present invention can be applied to the national VI SCR system and the front - stage and rear - stage SCR systems of national VII, with high integration, compact space, low back pressure, good mixing effect, and excellent anti - crystallization performance. Description of the Drawings

[0022] Figure 1 It is an exploded view of the end - cover side - inlet mixer of the present invention.

[0023] Figure 2 It is a perspective view of the end - cover side - inlet mixer of the present invention.

[0024] Figure 3 It is a working principle diagram of the end - cover side - inlet mixer of the present invention.

[0025] Figure 4 It is a position description diagram of the first opening and the second opening of the end - cover side - inlet mixer of the present invention. Detailed Embodiments

[0026] In order to make the technical problems solved by the present invention clearer, the present invention is further described below in conjunction with embodiments and drawings. The specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0027] As Figures 1 to 4As shown in the figure, this is an embodiment of the end - cover side - inlet mixer of the present invention, which reduces the system back - pressure, saves design space, reduces urea crystallization, and improves the mixing efficiency of urea and exhaust gas and the De - NOx conversion efficiency. Among them, the mixer includes an end - cover housing 1, and the end - cover housing 1 includes: an open end 11, a closed end, a cylinder 1, and an inner cavity composed of the open end 11, the closed end, and the cylinder 1. The open end 11 is the gas outlet of the mixer; the closed end, opposite to the open end 11, in this embodiment, the closed end is formed by closing the end of the cylinder with an end - cover 4; the cylinder 1 is located between the open end 11 and the closed end, and the cylinder 1 is a cylindrical cylinder with a longitudinal axis. The first opening 9 and the second opening 10 are independently arranged on the cylinder 1. The first opening 9 is used to install a nozzle 2, and the second opening 10 is the gas inlet of the mixer, and an inlet pipe 7 can be installed on the second opening 10.

[0028] A swirl tube 6, a first baffle 3, and a second baffle 5 are arranged in the inner cavity. The swirl tube 6 has a top pipe orifice, a bottom pipe orifice, and several side openings opened on the side wall of the swirl tube. The swirl tube can form a swirl effect and contact and mix with the reductant sprayed by the nozzle. Among them, the top pipe orifice is used to receive the reductant sprayed by the nozzle 2.

[0029] As Figures 1 to 3 shown, the first baffle 3 is located between the open end 11 and the swirl tube 6, and the second baffle 5 is installed on the bottom pipe orifice.

[0030] As Figure 2 shown, a first cavity 15 is formed among the first baffle 3, the cylinder 1, the closed end, and the second baffle 5. For the first cavity 15, the second opening 10 is the inlet for gas to flow into the first cavity 15, and the side opening is the outlet for gas to flow out of the first cavity 15.

[0031] As Figure 2 shown, a second cavity 14 is formed among the first baffle 3, the cylinder 1, the open end 11, and the second baffle 5. For the second cavity 14, the bottom pipe orifice is the inlet for gas to flow into the second cavity, and the open end 11 is the outlet for gas to flow out of the second cavity, so that the gas flowing in from the side opening mixes with the reductant sprayed by the nozzle in the swirl tube, heat exchange occurs in the swirl tube, urea is evaporated into ammonia, and then it flows out through the bottom pipe orifice and the open end in sequence.

[0032] In the mixer of the present invention, as Figure 1 and Figure 2As shown, the vertical projection of the second baffle 5 covers the bottom pipe opening, and there is a spaced space 17 between the second baffle 5 and the inner wall position of the cylinder 1 corresponding to the bottom pipe opening. As Figure 3 shown, the gas entering from the second opening 10 heats the second baffle 5 through the spaced space 17 in the first cavity.

[0033] Based on the mixer structure of the present invention, the intake air of the mixer enters the outside of the second baffle of the mixer. The inner side of the second baffle is the high-risk crystallization area of the mixer. The high-temperature gas wraps the outside of the second baffle and heats the second baffle from the outside, which is beneficial to the removal of crystallization on the inner side.

[0034] Specifically, as Figure 1 and Figure 2 shown, the second baffle 5 has a mounting portion 16 and an arc-shaped resisting portion. The arc-shaped resisting portion extends obliquely downward from a part of the mounting portion 16 and extends to the inner wall of the cylinder 1. The high-temperature gas entering from the second opening 10 heats the arc-shaped resisting portion through the spaced space. The arc-shaped resisting portion can also be a bowl-shaped resisting portion.

[0035] As Figures 1 to 3 shown, the first baffle 3 has an arc portion matching the swirl tube 6. The arc portion of the first baffle 3 and the swirl tube 6 form an arc-shaped space for forming a swirl.

[0036] As Figures 1 to 3 shown, the side openings include several first side openings 13 and several second side openings 12. The first side openings 13 extend along the longitudinal axis of the swirl tube 6. The first side openings 13 are spaced apart and distributed on the side surface of the swirl tube 6 facing away from the closed end. The longitudinal length of the first side openings 13 is 0.1 to 0.99 times the longitudinal length of the side wall of the swirl tube 6. The second side openings 12 are located above the first side openings. The second side openings 12 are spaced apart and distributed on the side wall of the swirl tube.

[0037] The gas in the first cavity can enter the swirl tube through the second side openings or through the first side openings. The swirling effect of the gas entering through the first side openings is further enhanced.

[0038] As Figure 1 and Figure 2 shown, blades are provided on some of the first side openings 13. The blades form a preset angle with the side wall of the swirl tube 6, and the blades can face inward or outward.

[0039] As Figure 4As shown, the central axis 18 of the second opening 10 overlaps with the central axis 19 of the first opening 9 after rotating 5° to 355° around the longitudinal axis of the cylinder 1. That is, from the cross-section of the cylinder, the included angle between the second opening and the first opening is between 5° and 355°. Alternatively, the position of the second opening 10 can also be adjusted so that the central axis 18 of the second opening 10 is parallel to the central axis 19 of the first opening 9 after rotating 5° to 355° around the longitudinal axis of the cylinder 1.

[0040] The longitudinal axis of the cyclone tube 6 forms a preset angle with the longitudinal axis of the cylinder 1, and the preset angle is 60° to 120°, preferably about 90°. The cyclone tube can be a circular tube body, an oval tube body, or other similar-shaped tube bodies.

[0041] As Figures 1 to 3 As shown, an air outlet baffle 8 is provided at the open end. The air outlet baffle 8 has a first blocking portion and a second blocking portion located above the first blocking portion. The first blocking portion is used to completely close the area of the open end corresponding to the first blocking portion to close the bottom of the air outlet, and the second blocking portion is provided with several third openings so that the second blocking portion partially closes the area of the open end corresponding to the second blocking portion.

[0042] The end-cap side-inlet mixer of the present invention can be applied to the national VI SCR system and the front-stage and rear-stage SCR systems of national VII, with high integration, compact space, low back pressure, good mixing effect, and excellent anti-crystallization performance.

[0043] The above are the specific embodiments of the present invention, which do not constitute a limitation to the protection scope of the present invention. Any modification and deformation made on the technical concept of the present invention should be included within the protection scope of the present invention.

Claims

1. An end cover side-entry mixer, characterized in that: The end cover housing comprises: An open end, wherein the open end is an air outlet of the mixer; a closed end, opposite to the open end; A barrel, located between the open end and the closed end, wherein the first opening and the second opening are independently arranged on the barrel, wherein the first opening is used to install the nozzle, and the second opening is the air inlet of the mixer; An inner cavity, wherein a swirl tube, a first baffle and a second baffle are arranged in the inner cavity, and the swirl tube has a top tube opening, a bottom tube opening and a plurality of side openings opened on the side wall of the swirl tube; The top pipe opening is used to receive the reducing agent sprayed by the nozzle; The first baffle is located between the open end and the swirl tube, the second baffle is installed on the bottom pipe opening, the first baffle, the cylinder, the closed end, and the second baffle form a first cavity, the second opening is the inlet for gas to flow into the first cavity, the side opening is the outlet for gas to flow out of the first cavity, the first baffle, the cylinder, the open end, and the second baffle form a second cavity, the bottom pipe opening is the inlet for gas to flow into the second cavity, and the open end is the outlet for gas to flow out of the second cavity, so that the gas flowing in from the side opening and the reducing agent sprayed by the nozzle are mixed in the swirl tube and then flow out through the bottom pipe opening and the open end in sequence; The vertical projection of the second baffle covers the bottom pipe opening, and there is a spacing space between the second baffle and the inner wall position of the cylinder corresponding to the bottom pipe opening, and the gas entering from the second opening heats the second baffle through the spacing space in the first cavity.

2. The end cover side-entry mixer according to claim 1, characterized in that: The second baffle has a mounting portion and an arc-shaped resisting portion, wherein the arc-shaped resisting portion extends obliquely downward from a portion of the mounting portion and extends to the inner wall of the cylinder, and the high-temperature gas entering from the second opening heats the arc-shaped resisting portion through the spacing space.

3. The end cover side-entry mixer according to claim 1, characterized in that: The first baffle has an arc portion matching the vortex tube. The arc portion of the first baffle and the vortex tube form an arc-shaped space, and the arc-shaped space is used to form a vortex.

4. The end cover side-entry mixer according to claim 1 or 3, characterized in that: The side openings include several first side openings and several second side openings, the first side openings extend along the longitudinal axis of the vortex tube, the first side openings are spaced apart on the side of the side wall of the vortex tube away from the closed end, and the longitudinal length of the first side openings is 0.1 to 0.99 times the longitudinal length of the side wall of the vortex tube; the second side openings are located above the first side openings, and the second side openings are spaced apart on the side wall of the vortex tube.

5. The end cover side-entry mixer according to claim 4, characterized in that: At least one of the first side openings is provided with blades, and the blades are at a preset angle with the side wall of the cyclone tube.

6. The end cover side-entry mixer according to claim 1, characterized in that: The central axis of the second opening is rotated 5° to 355° around the longitudinal axis of the cylinder to overlap or be parallel to the central axis of the first opening.

7. The end cover side-entry mixer according to claim 1, characterized in that: The longitudinal axis of the cyclone tube forms a preset angle with the longitudinal axis of the cylinder, and the preset angle is 60° to 120°.

8. The end cover side-entry mixer according to claim 1, characterized in that: An air outlet baffle is provided at the open end, and the air outlet baffle has a first resisting portion and a second resisting portion located above the first resisting portion, the first resisting portion is used to completely close the area of ​​the open end corresponding to the first resisting portion to close the bottom of the air outlet, and the second resisting portion is provided with a plurality of third openings, so that the second resisting portion partially closes the area of ​​the open end corresponding to the second resisting portion.

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