CN108952905B

CN108952905B - Mixing device

Info

Publication number: CN108952905B
Application number: CN201810775605.6A
Authority: CN
Inventors: 王伟; 童毅君; 王聪; 毛伟; 赵治国
Original assignee: Tiannake (suzhou) Emission System Co Ltd
Current assignee: Tiannake (suzhou) Emission System Co Ltd
Priority date: 2015-12-18
Filing date: 2015-12-18
Publication date: 2020-01-03
Anticipated expiration: 2035-12-18
Also published as: CN108952905A; CN106894870B; CN106894870A

Abstract

The utility model provides a mixing arrangement for among the engine exhaust aftertreatment device, mixing arrangement includes the hybrid tube, the hybrid tube includes hollow interior cavity, centers on the periphery of interior cavity and along a plurality of fins of circumference distribution and corresponding to a plurality of fins and with a plurality of flutings of interior cavity intercommunication. The mixing device also comprises a sleeve part sleeved on the periphery of the mixing pipe, the sleeve part is provided with the expansion cavity and an end wall positioned at the root part of the expansion cavity, and the end wall is provided with a through hole for the mixing pipe to pass through. The plurality of fin portions extend into the expansion cavity. By providing an expansion chamber, the mounting of the mixing tube is not limited to the overall size of the engine exhaust aftertreatment device.

Description

Mixing device

This application is a divisional application filed on 2015, 12/18, application No. 201510957888.2, entitled "engine exhaust gas post-treatment device".

Technical Field

The invention relates to a mixing device, and belongs to the technical field of engine exhaust aftertreatment.

Background

Engine exhaust gas after-treatment devices (e.g., diesel exhaust gas after-treatment devices) are devices mainly used for treating or purifying toxic and harmful substances in exhaust gas. The toxic substances in the exhaust gas mainly comprise hydrocarbons, carbon monoxide, nitrogen oxides, particulate matters and the like.

The art has developed solutions that combine oxidation-type catalytic converters (DOCs), particulate traps (DPFs), and Selective Catalytic Reduction (SCR) systems to improve the effectiveness of exhaust treatment. In one arrangement, the oxidation catalyst and the particulate trap are disposed in series within a first housing; the selective catalytic reduction agent is disposed within the second housing; the first and second housings are then connected in series by means of a connecting conduit.

In order to enable the exhaust gas to be uniformly mixed with the atomized urea solution in the connecting duct, technical solutions using a mixing tube or a static mixer have been provided in the prior art. Among them, the mixing pipe is generally used under the condition that the engine exhaust aftertreatment device can provide a sufficient installation space. When the installation space is not enough, the technical scheme of the static mixer is generally adopted.

However, because the cost and performance of the mixing tube are sometimes advantageous over static mixers, the overall size of the engine exhaust aftertreatment device is limited by the fact that the customer's installation size is not infinitely wide, and the mixing structure on the mixing tube has a certain length, so that how to install such a mixing tube even when the overall size of the engine exhaust aftertreatment device is small becomes one of the technical problems to be solved by the industry.

Disclosure of Invention

The invention aims to provide a mixing device, the installation of which is not limited to the whole size of an engine exhaust aftertreatment device.

In order to achieve the purpose, the invention adopts the following technical scheme: a mixing device is used in an engine exhaust aftertreatment device and comprises a mixing pipe, wherein the mixing pipe comprises a hollow inner cavity, a plurality of fins which surround the periphery of the inner cavity and are distributed along the circumferential direction, and a plurality of slots which correspond to the fins and are communicated with the inner cavity; the mixing device also comprises a sleeve part sleeved on the periphery of the mixing pipe, the sleeve part is provided with the expansion cavity and an end wall positioned at the root part of the expansion cavity, and the end wall is provided with a through hole for the mixing pipe to pass through; the plurality of fin portions extend into the expansion cavity.

As a further improved technical scheme of the invention, the joint of the mixing pipe and the through hole is welded and sealed.

Compared with the prior art, the mixing pipe is not limited to the whole size of the engine exhaust aftertreatment device by arranging the expansion cavity, the back pressure of the system can be flexibly adjusted by adjusting the volume of the expansion cavity, and the standardized design is realized.

Drawings

FIG. 1 is a schematic perspective view of an engine exhaust aftertreatment device of the present invention.

Fig. 2 is a perspective view of fig. 1 from another angle.

Fig. 3 is a partially exploded perspective view of fig. 2.

Fig. 4 is a further exploded perspective view of fig. 3.

Fig. 5 is a further exploded perspective view of fig. 4.

Fig. 6 is a partial perspective view of fig. 1 with portions of the housing and nozzle removed.

Fig. 7 is a partially exploded perspective view of fig. 6 with the sleeve portion separated.

Fig. 8 is an exploded perspective view from another angle of fig. 7.

FIG. 9 is a schematic cross-sectional view taken along line A-A of FIG. 1 and indicates the direction of swirl of the exhaust gas as it enters the mixing tube.

Fig. 10 is a schematic sectional view taken along line B-B in fig. 1.

Detailed Description

Referring to fig. 1 and 2, an engine exhaust aftertreatment device 100 is disclosed, which includes an upstream aftertreatment component 2 disposed in a housing 1, a downstream aftertreatment component 3 connected in series with the upstream aftertreatment component 2, and a mixing pipe 4 connecting the upstream and downstream aftertreatment components 2, 3 in series.

In the illustrated embodiment of the invention, the upstream aftertreatment component 2 comprises an oxidation catalyst (DOC)21 and/or a particulate trap (DPF)22, wherein the oxidation catalyst 21 is located upstream of the particulate trap 22 to provide a suitable temperature when the particulate trap 22 is regenerated.

The downstream aftertreatment component 3 includes a Selective Catalytic Reduction (SCR). In the illustrated embodiment of the present invention, the selective catalytic reduction agents include a first group 31 of selective catalytic reduction agents and a second group 32 of selective catalytic reduction agents arranged side by side, the first group 31 of selective catalytic reduction agents being connected in parallel with the second group 32 of selective catalytic reduction agents.

The housing 1 includes a cylindrical portion 11, a first outer side plate 12 at one end of the cylindrical portion 11, a second outer side plate 13 at the other end of the cylindrical portion 11, an inlet 14 connected to the second outer side plate 13 and adapted to communicate with exhaust gas of the engine, and an outlet 15 passing through the first outer side plate 12. Referring to fig. 10, the housing 1 is further provided with a plurality of support plates 16 disposed therein for supporting the upstream aftertreatment component 2 and the downstream aftertreatment component 3. Wherein the support plate 16 comprises a first end plate 5 adjacent to the outlet 15.

Referring to fig. 7, the first end plate 5 includes a first perforation 51 corresponding to the particulate trap (DPF)22, a second perforation 52 corresponding to the first set of selective catalytic reduction agents 31, a third perforation 53 corresponding to the second set of selective catalytic reduction agents 32, and a first opening 54 through which at least a portion of the mixing pipe 4 passes.

Referring to fig. 3 to 10, the housing 1 includes a first inner side plate 61 and a second inner side plate 62 fixed to the first end plate 5, wherein the first inner side plate 61 is welded to the first end plate 5 to form a first cavity 71 therebetween, and the first inner side plate 61 covers the first through hole 51 and the first opening 54; the second inner side plate 62 is welded to the first end plate 5 to form a second cavity 72 therebetween, and the second inner side plate 62 covers the second through hole 52 and the third through hole 53. The outlet 15 communicates with the second chamber 72.

The housing 1 is provided with a nozzle mounting portion 17 corresponding to the mixing pipe 4 for mounting a urea nozzle 18.

Referring to fig. 7 and 10, in the illustrated embodiment of the present invention, the mixing tube 4 is cylindrical and includes a hollow inner cavity 41, a plurality of fins 42 circumferentially distributed around the inner cavity 41, a plurality of slots 43 corresponding to the plurality of fins 42 and communicating with the inner cavity 41, and a plurality of openings 44 located at one side of the fins 42 and near the nozzle mounting portion 17. In the illustrated embodiment of the present invention, the slots 43 are formed by punching the fins 42, and the openings 44 are uniformly distributed on the periphery of the inner cavity 41 along the circumferential direction. Referring to fig. 9, the fins 42 are arranged at an angle so that the exhaust gas passing through the slots 43 can form a good vortex in the inner cavity 41.

Referring to fig. 6 to 8 and 10, the housing 1 includes a sleeve portion 8 fixed to the first opening 54. The sleeve portion 8 is provided with an expansion chamber 81 and an end wall 82 at the root of the expansion chamber 81. The end wall 82 is provided with a through hole 821 through which the mixing tube 4 passes. The expansion cavity 81 is communicated with the first cavity 71, the expansion cavity 81 and the first cavity 71 are respectively located at two sides of the first end plate 5, wherein the fin 42 and the slot 43 penetrate through the first cavity 71, and the fin 42 and the slot 43 are jointly accommodated in the first cavity 71 and the expansion cavity 81.

In the illustrated embodiment of the present invention, the sleeve portion 8 is welded to the inside of the first opening 54. The junction of the mixing pipe 4 and the through hole 821 is welded and sealed.

In use, exhaust gas from the engine first enters from the inlet 14, then passes through the oxidation-type catalytic converter 21 and the particulate trap 22 in sequence, and then enters the first cavity 71 from the first through hole 51; under the action of the exhaust pressure, the exhaust gas enters the inner cavity 41 through the slots 43 and the openings 44 under the guidance of the fins 42; when the spraying condition is reached, the urea nozzle 18 directly sprays the atomized urea solution into the inner cavity 41; the exhaust gas mixed with the urea droplets is divided into two paths to enter the first group of selective catalytic reducing agents 31 and the second group of selective catalytic reducing agents 32 at the same time, then is converged by the second cavity 72, and finally exits from the outlet 15.

In the illustrated embodiment of the invention, the nozzle mounting portion 17 is adjacent to the plurality of openings 44. Since the urea solution sprayed from the urea nozzle 18 tends to form a dead zone at a position far from the nozzle opening, which tends to cause crystallization, the urea solution at this position can flow out of the opening 44 after the solution of the present invention, thereby reducing the risk of urea crystallization. The urea solution sprayed from the urea nozzle 18 is surrounded by the swirling exhaust gas in the inner cavity 41 of the mixing pipe 4, thereby avoiding direct contact of urea with the inner wall and reducing the risk of crystallization. The swirling exhaust gas can improve the uniformity of mixing with the atomized urea solution, thereby improving the efficiency of exhaust gas treatment and enabling the scheme of the invention to meet the requirements of stricter emission regulations.

Since the mixing structure (e.g., fins 42, slots 43, apertures 44, etc.) of the mixing tube 4 has a certain length, it may be difficult to achieve the requirements for mounting the mixing structure using only the size of the first cavity 71 if the sleeve portion 8 is not provided. The sleeve part 8 is arranged, so that the installation space is increased in the engine exhaust aftertreatment device 100, the size of the whole engine exhaust aftertreatment device 100 is not limited, the back pressure of a system can be flexibly adjusted by adjusting the volume of the expansion cavity 81, and the standardized design is realized.

In addition, the above embodiments are only used for illustrating the invention and not for limiting the technical solutions described in the invention, and the understanding of the present specification should be based on the technical personnel in the field, and although the present specification has described the invention in detail by referring to the above embodiments, the ordinary skilled in the art should understand that the technical personnel in the field can still make modifications or equivalent substitutions to the present invention, and all the technical solutions and modifications thereof without departing from the spirit and scope of the present invention should be covered in the claims of the present invention.

Claims

1. A mixing device is used in an engine exhaust aftertreatment device and comprises a mixing pipe, wherein the mixing pipe comprises a hollow inner cavity, a plurality of fins which surround the periphery of the inner cavity and are distributed along the circumferential direction, and a plurality of slots which correspond to the fins and are communicated with the inner cavity; the method is characterized in that: the mixing device also comprises a sleeve part sleeved on the periphery of the mixing pipe, the sleeve part is provided with an expansion cavity and an end wall positioned at the root part of the expansion cavity, and the end wall is provided with a through hole for the mixing pipe to pass through; the plurality of fin portions extend into the expansion cavity.

2. The mixing device of claim 1, wherein: and the joint of the mixing pipe and the through hole is welded and sealed.