KR20160040687A - Mirrored two-stage mixer - Google Patents

Abstract

The mixer for the aftertreatment system may comprise a housing and first and second deflector groups. The first deflector groups can be disposed within the housing and arranged relative to each other to direct fluid flowing through the first deflector group into a first vortex pair that rotates in opposite directions with respect to each other. The second deflector groups can be disposed within the housing and arranged relative to each other to direct fluid flowing through the second deflector group into a second vortex pair rotating in opposite directions with respect to each other. The first and second deflector groups may be rotationally symmetric with respect to each other about a longitudinal axis of the housing.

Description

Mirrored Two-Stage Mixer {MIRRORED TWO-STAGE MIXER}

The present disclosure relates to a mixer for an exhaust aftertreatment system for a combustion engine.

This section provides background information relating to the present disclosure, not necessarily the prior art.

Selective catalytic reduction techniques have been used with reducing nitrogen oxides present in the exhaust of combustion engines. Many vehicles using combustion engines are equipped with an exhaust aftertreatment apparatus for reducing nitric oxide emissions. Some of these systems are constructed using element-based techniques including a container for storing a reducing agent (e.g., urea) and a delivery system for delivering the reducing agent from the container to the exhaust stream. In order to mix the injected reducing agent with the exhaust gas before the reducing agent reaches the catalyst to be reacted with the reducing agent, a mixer is typically provided downstream of the reducing agent injector. While such a system may have worked well so far, it may be desirable to provide an improved mixer to more efficiently and effectively mix the reducing agent with the exhaust stream and to provide a more uniform distribution of the reducing agent over a larger area of the catalyst have.

This section is provided to provide an overview of the present disclosure and is not a comprehensive disclosure of the entire category or all features.

In one aspect, the disclosure provides an exhaust aftertreatment system that can include an exhaust passageway, an exhaust aftertreatment device, and a mixer. The exhaust passage can receive exhaust gas from the engine. The exhaust after-treatment apparatus can be disposed in the exhaust passage. The mixer may be disposed in the exhaust passage upstream of the exhaust aftertreatment apparatus. The mixer may include a housing and first and second deflector groups. The first deflector groups can be disposed within the housing and arranged relative to each other to direct fluid flowing through the first deflector group into a first vortex pair that rotates in opposite directions with respect to each other. The second deflector groups can be disposed within the housing and arranged relative to each other to direct fluid flowing through the second deflector group into a second vortex pair rotating in opposite directions with respect to each other. The first and second deflector groups may be rotationally symmetric with respect to each other about a longitudinal axis of the housing.

In some embodiments, the exhaust aftertreatment apparatus may comprise a catalyst.

In some embodiments, the post-treatment apparatus may have a round shape. In some embodiments, the post-processing apparatus may have a triangular shape. In some embodiments, the post processing apparatus may have a square shape.

In some embodiments, the exhaust aftertreatment system may include a reducing agent delivery system having a reducing agent injector arranged to inject a reducing agent (e.g., urea or ammonia) into the exhaust passageway upstream of the first and second deflector groups have.

In some embodiments, the exhaust aftertreatment system may include a reducing agent delivery system having first and second reducing agent injectors arranged to inject a reducing agent into the exhaust passageway upstream of the first and second deflector groups.

In some embodiments, the housing may include first and second ports to allow a reducing agent to be injected from the first and second reducing agent injectors, respectively, into the housing. The first and second ports are arranged such that most of the reducing agent injected through the first port flows through the first deflector group and most of the reducing agent injected through the second port flows through the second deflector group, And the second deflector group.

In some embodiments, the mixer may include a third deflector group disposed in the housing, wherein the third deflector group includes a third vortex that rotates fluid flowing through the third deflector group in opposite directions to each other, Lt; RTI ID = 0.0 > and / or < / RTI >

In some embodiments, the first, second, and third deflector groups may be rotationally symmetric with respect to each other about a longitudinal axis.

In some embodiments, the housing may include first, second, and third ports, wherein the first, second, and third ports are configured such that most of the reducing agent injected through the first port Most of the reducing agent flowing through the perfume group and flowing through the second port flows through the second deflector group and most of the reducing agent injected through the third port flows through the third deflector group, , And a third deflector group.

In some embodiments, the mixer may include a fourth deflector group disposed in the housing, wherein the fourth deflector group includes a fourth vortex that rotates fluid flowing through the fourth deflector group in opposite directions to each other, Lt; RTI ID = 0.0 > and / or < / RTI >

In some embodiments, the first, second, third, and fourth deflector groups may be rotationally symmetric with respect to each other about the longitudinal axis.

In some embodiments, the housing may include first, second, third, and fourth ports, wherein the first, second, third, and fourth ports are configured to receive a majority Of the reducing agent flows through the first deflector group and most of the reducing agent injected through the second port flows through the second deflector group and most of the reducing agent injected through the third port flows through the third deflector group Second, third, and fourth deflector groups so that most of the reducing agent injected through the fourth port flows through the fourth deflector group.

In some embodiments, each of the first and second groups of deflectors may include a plurality of plates extending parallel to the longitudinal axis of the housing, each plate comprising a plurality of tabs angled relative to the plate and the longitudinal axis, .

In some embodiments, the plurality of tabs of each plurality of plates includes a plurality of first tabs extending in a first direction from a first side of a corresponding plate, and a plurality of first tabs extending in a second direction from a second opposite side of the corresponding plate And a plurality of second tabs.

In some embodiments, the housing can be a generally tubular member.

In some embodiments, the post-treatment apparatus may have a round shape. In some embodiments, the post-processing apparatus may have a triangular shape. In some embodiments, the post processing apparatus may have a square shape.

In another aspect, the present disclosure provides a mixer for an exhaust aftertreatment system that can include a housing and first and second deflector groups. The first deflector group can be disposed within the housing and can be arranged to generate a first counter-rotating vortex pair. The second deflector group may be disposed within the housing and may be arranged to generate a second counter-rotating vortex pair. The first and second deflector groups may be arranged in a circular array about the longitudinal axis of the housing.

In some embodiments, the mixer may include a third deflector group disposed in the housing and arranged to generate a third reverse-rotating vortex pair.

In some embodiments, the circular array may include a third deflector group.

In some embodiments, the mixer may include a fourth deflector group disposed in the housing and arranged to generate a fourth counter-rotating vortex pair.

In some embodiments, the circular array may include a fourth deflector group.

In some embodiments, the mixer may include a fifth deflector group centered on the longitudinal axis and surrounded by first, second, third, and fourth deflector groups.

In some embodiments, some or all of the first, second, third, and fourth deflector groups are rotationally oriented differently from each other.

In some embodiments, the first and second deflector groups may be surrounded by a first and a second collar, respectively.

In some embodiments, the first and second collar may comprise first and second longitudinal axes, respectively, formed about the longitudinal axis of the housing and angled relative to each other. This orientation of the first and second deflector groups can drive fluid flow into the corners of a non-circular selective catalytic reduction (SCR) catalyst or other post-treatment apparatus.

Additional application fields will become apparent from the description provided herein. The description and specific examples of such schemes are for illustrative purposes only and are not intended to limit the scope of the present disclosure.

The drawings described herein are for illustrative purposes only, and are not intended to limit the scope of the present disclosure, rather than all possible embodiments.
1 is a schematic diagram of an exhaust system and engine with a post-treatment system in accordance with the principles of the present disclosure;
2 is a perspective view of a mixer of the post-treatment system of FIG. 1 in accordance with the principles of the present disclosure;
Figure 3 is another perspective view of the mixer of Figure 2;
4 is a cross-sectional view of the mixer.
5 is a plan view of the mixer showing the direction of rotation of the vortex generated by the mixer as fluid flows through the mixer.
Figure 6 is a perspective view of another mixer in accordance with the principles of the present disclosure;
Figure 7 is another perspective view of the mixer of Figure 6;
8 is a cross-sectional view of the mixer of FIG.
Figure 9 is a plan view of the mixer of Figure 6 showing the direction of rotation of the vortex generated by the mixer as fluid flows through the mixer;
10 is a perspective view of another mixer in accordance with the principles of the present disclosure;
11 is another perspective view of the mixer of FIG.
12 is a cross-sectional view of the mixer of FIG.
Figure 13 is a plan view of the mixer of Figure 10 showing the direction of rotation of the vortex generated by the mixer as fluid flows through the mixer.
14 is a perspective view of another mixer with a plurality of deflector groups according to the principles of the present disclosure;
Figure 15 is a perspective view of one deflector group of the mixer of Figure 14;
Figure 16 is another perspective view of the deflector group of Figure 15;
Figure 17 is a plan view of the deflector group of Figure 15 showing the direction of rotation of the vortex generated by the deflector group as fluid flows through the deflector group.
Corresponding reference characters indicate corresponding elements throughout the several views.

Exemplary implementations will now be described in more detail with reference to the accompanying drawings.

The exemplary embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Many specific details, such as examples of specific components, devices, and methods, are set forth in order to provide a thorough understanding of the implementations of the present disclosure. It will be apparent, however, to one skilled in the art that the specific details need not be employed, that the illustrative embodiments may be implemented in a number of different forms, and neither should be construed as limiting the scope of the present disclosure. In some exemplary embodiments, well-known processes, well-known device structures, and well-known techniques are not described in detail.

The terminology used herein is for the purpose of describing particular illustrative embodiments only, and is not intended to be limiting. As used herein, unless the context clearly indicates otherwise, "a, an, the" may be intended to include plural forms. The terms "comprises", "comprising", "having", and "having" are inclusive and thus denote the presence of stated features, integers, steps, operations, elements, and / Does not preclude the presence or addition of other features, integers, steps, operations, elements, components, and / or groups thereof. The method steps, processes, and operations described herein should not be construed as necessarily requiring their performance to be performed in the specific order discussed or illustrated unless the order of execution is specifically stated. It is also to be understood that additional or alternative steps may be employed.

When an element or layer is referred to as being "on," "engaged," "attached to," "connected to," or "coupled to" another element or layer, it may be directly on top of another element or layer, May be engaged, attached, connected or joined together, or intervening elements or layers may be present. Conversely, when an element is referred to as being "directly over," "directly engaged," "directly attached to," "directly connected to," or "directly coupled to" another element or layer, It may not exist. Other terms used to describe the relationship between elements should be interpreted in a similar manner (e.g., between "between" and "immediately", "adjacent" and "immediately adjacent"). As used herein, the term "and / or" includes any and all combinations of one or more associated entry items.

It should be understood that although the terms first, second, third, etc. may be used herein to describe various elements, components, groups of components, regions, layers, and / Elements, groups of elements, regions, layers, and / or portions should not be limited by these terms. These terms may only be used to distinguish one element, element, group of elements, region, layer, or portion from another element, element, element group, region, layer, or portion. As used herein, terms such as " first ", "second ", and other numerical terms do not imply rank or order, unless the context clearly dictates otherwise. Thus, the first element, component, region, layer or portion discussed below may be represented as a second element, component, region, layer or section without departing from the teachings of the exemplary embodiments.

Bearing terms such as spatial relative terms such as "inside", "outside", "under", "under", "under", "above", "top", and upward, downward, clockwise, counterclockwise, May be used herein for convenience of explanation to describe the relationship of one element or feature to another element (s) or feature (s), as shown in the figures. Spatial relative terms may be intended to encompass different orientations of the device during use or operation, in addition to the orientations shown in the figures. For example, where the orientation of a device is reversed in the figures, elements described as being "under" or "under" another element or feature will be oriented "above" another element or feature. Thus, an exemplary term "below" can encompass both the top and bottom orientations. The device can be oriented differently (90 degrees rotation or other orientation) and the spatial relative descriptors used herein can be interpreted accordingly.

1, there is provided an exhaust aftertreatment system 10 that can include an exhaust passageway 12, a reducing agent delivery system 14, a post-treatment device 16, and a mixer 18. The exhaust passage 12 can receive the exhaust gas discharged from the combustion engine 20. [ The exhaust gas discharged into the exhaust passage 12 flows through the mixer 18 and the post-treatment device 16 and can be discharged to the surrounding environment. The reducing agent delivery system 14 may pump a reducing agent (e.g., urea or ammonia) from the tank 22 into the at least one reducing agent injector 24, which is fed to the exhaust stream at or near the mixer 18 Reducing agent can be sprayed. The mixer 18 may mix the reducing agent with the exhaust gas to provide a more homogeneous mixture of reducing agent and exhaust gas, after which the mixture enters the aftertreatment device 16.

The post-treatment apparatus 16 may be, for example, a selective catalytic reduction (SCR) catalyst. The reaction between the reducing agent and the post-treatment apparatus 16 can convert, for example, nitrogen oxide in the exhaust gas to nitrogen (N ₂ ), water, and / or carbon dioxide. The post-processing device 16 may include any suitable shape, such as a circular shape (as shown in Figure 5), a triangular shape (as shown in Figure 9), or a rectangular or square shape (as shown in Figure 13) Shape.

Referring now to FIGS. 2-5, the mixer 18 may include a housing 26, a first deflector group 27, and a second deflector group 28. The housing 26 may be a generally tubular member having first and second injector ports 30,32 and a longitudinal axis A. [ The first and second injector ports 30,32 may be disposed between the upstream end 33 of the housing 26 and the downstream end 35 of the housing 26. [ Each injector port 30, 32 can receive a corresponding one reducing agent injector 24 (as shown schematically in FIG. 4). The reducing agent injectors 24 may inject a reducing agent into the mixer 18 upstream of the first and second deflector groups 27 and 28. Although injectors 24 are shown in the figures as being positioned to atomize the reducing agent in a direction perpendicular to the exhaust gas flow direction, injectors 24 and injector ports 30, 32, in some embodiments, And may be positioned at an angle relative to the flow direction. It is understood that the injectors 24 and injector ports 30, 32 may be located at any location and in any orientation.

The first deflector group 27 may include first and second plates 34 and 36 and a first half or portion 37 of the third plate 38. Second deflector group 28 may include fourth and fifth plates 39 and 41 and a second half or portion 43 of third plate 38. The first, second, fourth, and fifth plates 34, 36, 39, 41 may be approximately parallel to one another and may be parallel to the longitudinal axis A of the housing 26. The third plate 38 may be substantially parallel to the first, second, fourth, and fifth plates 34, 36, 39, 41 and may extend along the longitudinal axis A. The side ends of the first, second, third, fourth and fifth plates 34, 36, 38, 39, 41 may be joined to the first and second plates by any appropriate means, for example by welding, fasteners and / And can be fixedly attached to the housing 26. For example, in some embodiments, the side ends of the plates 34, 36, 38, 39, 41 include legs (not shown) extending upwardly or downwardly therefrom and engaging the inner diameter of the housing 26 . The legs may be welded, for example, to the inner diameter of the housing 26 or otherwise connected.

The first plate 34 includes an upstream end 40, a downstream end 42, a plurality of incisions 44 (best seen in Figure 3), a plurality of first deflectors 46, A perfume 48, and one or more third deflector 50. [ The cuts 44 and the first deflectors 46 may be disposed between the upstream and downstream ends 40,42. The first deflectors 46 are partially cut or stamped from the first plate 34 (to form the cuts 44) Of the reference frame). In this manner, when fluid flows from the upstream end 33 to the downstream end 35 through the housing 26, the first deflectors 46 can deflect the fluid downward through the cutouts 44 .

Second deflectors 48 may be disposed at or adjacent to the downstream end 42 of the first plate 34 and may extend downwardly from the first plate 34 and downstream end 35 of the housing 26. [ Lt; / RTI > The third deflector 50 may be disposed at or near the downstream end 42 of the first plate 34 and between the second deflectors 48. The third deflector 50 may extend upwardly from the first plate 34 and toward the downstream end 35 of the housing 26. The third deflector 50 may have a slot 52 formed therein. When the fluid flows from the upstream end 33 to the downstream end 35 through the housing 26 the second deflectors 48 can deflect the fluid downward and the third deflector 50 can deflect the fluid It is possible to deflect upward.

The second plate 36 may be substantially similar to the first plate 34 and may include an upstream end 54, a downstream end 56, a plurality of incisions 58 (best seen in Figure 3) A plurality of second deflectors 62, and one or more third deflectors 64. The first deflector 60 may include a first deflector 60, a plurality of second deflectors 62, The cuts 58 and deflectors 60,62 and 64 may be similar or identical to the cuts 44 and deflectors 46,48 and 50 of the first plate It will not be explained.

The third plate 38 may include an upstream end 66 and a downstream end 68. The first portion 37 of the third plate 38 may include a plurality of cutouts 70, a plurality of first deflectors 72, and a plurality of second deflectors 74. The cutouts 70 and the first deflectors 72 may be disposed between the upstream and downstream ends 66, 68. The first deflectors 72 are partially cut or stamped from the third plate 38 (to form the cuts 70) and are positioned at predetermined angles relative to the third plate 38 Of the reference frame). In this manner, when fluid flows from the upstream end 33 to the downstream end 35 through the housing 26, the first deflectors 72 can deflect the fluid upwardly through the cutouts 70 .

The second deflector 74 may be disposed at or adjacent to the downstream end 42 of the third plate 38 and may extend upwardly from the third plate 38 and upwardly away from the downstream end 35 of the housing 26 Lt; / RTI > When the fluid flows from the upstream end 33 to the downstream end 35 through the housing 26, the second deflector 74 can bias the fluid upward substantially.

The second deflector group 28 is similar to the first deflector group 27 except that the second deflector group 28 can be rotated 180 degrees from the first deflector group 27 Can be the same. That is, the first and second deflector groups 27 and 28 may be rotationally symmetric with respect to each other about the longitudinal axis A. The second portion 43 of the third plate 38 is substantially similar to the first portion 37 and the fourth and fifth plates 39 and 41 are substantially similar to the second and first plates 36 and 34, The second portion 43 and the fourth and fifth plates 39 and 41 will not be described in detail again. Briefly, the second portion 43 may include incisions 76, upwardly extending deflectors 78, and a downwardly extending deflector 80. The fourth plate 39 includes cutouts 82, downwardly extending first deflectors 84, upwardly extending second deflectors 86, and one downwardly extending third deflector 88, . ≪ / RTI > The fifth plate 41 includes cutouts 90, downwardly extending first deflectors 92, upwardly extending second deflectors 94, and one downwardly extending third deflector 96, . ≪ / RTI >

With continued reference to Figures 1-5, the operation of the system 10 will be described in detail. During operation of the engine 20, exhaust gas is discharged from the engine 20 into the exhaust passage 12 and flows through the mixer 18. [ When the exhaust flows through the mixer 18, the reducing agent delivery system 14 is configured to deliver the exhaust stream (e. G., Through injector ports 30 and 32) upstream of the first and second deflector groups 27 and 28 A reducing agent can be injected. By flowing through the first and second deflector groups 27 and 28, the reducing agent is mixed with the exhaust gas so that as the mixture flows into the post-treatment apparatus 16, the reducing agent is more uniformly distributed in the exhaust gas do.

As shown in FIG. 5, the first and second deflector groups 27 and 28 cause fluid flowing therethrough to form first and second vortex pairs. That is, the first deflector group 27 can generate the first vortex V1 rotating in the counterclockwise direction and the second vortex V2 rotating in the clockwise direction. The second deflector group 28 may generate a third vortex V3 rotating in the clockwise direction and a fourth vortex V4 rotating in the counterclockwise direction. The first and second vortices V1 and V2 are arranged side by side and may be disposed on the third plate 38 approximately. The arrangement of the third and fourth vortices V3 and V4 may be rotationally symmetric about the arrangement of the first and second vortices V1 and V2 about the longitudinal axis A. [

By creating the two counter-rotating vortices V1, V2, V3, V4, the mixer 18 can improve the overall uniformity of the fluid flow pattern on the upstream side of the post-treatment device 16 (i.e., The flow rate across the upstream surface of the device 16 may be more uniform). Providing the two pairs of counter-rotating vortices (instead of only one counter-rotating vortex pair) is advantageous in that the vortexes V1, V2, V3, V4 can be lost before flowing through the after- Can be reduced. The configuration of the first and second deflector groups 27 and 28 may be particularly advantageous when used with a post-treatment apparatus 16 having a circular cross-section (as shown in FIG. 5), but may have any other shape It can also be advantageous when used with post-processing equipment.

As described above, the mixer 18 may include a pair of injectors 24 for injecting the reducing agent through the injector ports 30, 32. In this way, each injector port 30, 32 can allow the reducing agent to be injected into the corresponding one of the counter-rotating vortex pairs V1, V2, V3, V4. In some embodiments, most of the reducing agent injected through the first injector port 30 can flow through the first deflector group 27 and most of the reducing agent injected through the second injector port 32 And may flow through the second deflector group 28. Since the injector 24 for each deflector group can provide a more uniform distribution of the reducing agent in the exhaust flow, it is advantageous to have a plurality of injectors 24, each corresponding to a particular deflector group 27, 28 Diameter mixer (such as, for example, a mixer having a 12 inch diameter).

6-9, another mixer 118, which may be incorporated into the system 10, is provided instead of the mixer 18. The mixer 118 may include a housing 126, a first deflector group 127, a second deflector group 128, a third deflector group 129, and a center mixer 130. The first, second and third deflector groups 127, 128 and 129 are arranged in a circular array about the longitudinal axis A of the housing 126 such that adjacent deflector groups are 120 degrees apart from each other . That is, the first, second and third deflector groups 127, 128 and 129 are arranged such that the first, second and third deflector groups 127, 128 and 129 are centered about the longitudinal axis A Can be uniformly distributed around the longitudinal axis A to form a rotationally symmetric pattern.

The housing 126 may be a tubular member including first, second, and third injection ports 131, 132, The first, second, and third injection ports 131, 132, 133 may be rotationally aligned with the first, second, and third deflector groups 127, 128, 129, respectively. As described above, the reducing agent injectors 24 can be accommodated in the corresponding injection ports 131, 132, 133. While it has been shown in the drawings that the injector ports 131, 132, 133 are positioned relative to the injectors 24 to atomize the reducing agent in a direction perpendicular to the direction of exhaust flow, in some embodiments injectors 24 And the injector ports 131, 132, 133 may be positioned at an angle relative to the exhaust gas flow direction. It is understood that the injectors 24 and injector ports 131, 132, 133 may be located at any location and in any orientation.

The first, second, and third deflector groups 127, 128, and 129 may be substantially similar to each other and may include first and second plates 134 and 136 that are approximately parallel to each other. The first plate 134 includes an upstream end 138, a downstream end 140, a plurality of incisions 142, a plurality of first deflectors 144, a plurality of second deflectors 146, And may include a third deflector 148. The cutouts 142 and the first deflectors 144 may be disposed between the upstream and downstream ends 138, 140. The first deflectors 144 may be partially cut or stamped out of the first plate 134 (to form the cutouts 142) so that the first deflectors 144 can be bent outwardly 1 plate 134 toward the inner peripheral surface of the housing 126 (i.e., away from the longitudinal axis) and toward the upstream end 138 at a predetermined angle. In this manner, when fluid flows from the upstream end 138 to the downstream end 140 through the housing 126, the first deflectors 144 move the second plate 136 through the cutouts 142 The fluid can be deflected toward the < / RTI >

The second deflectors 146 may be disposed at or adjacent the downstream end 140 of the first plate 134 and may extend from the first plate 134 toward the longitudinal axis A and away from the housing 126 And may extend toward the downstream end. The third deflector 148 may be disposed at or near the downstream end 140 of the first plate 134 and between the second deflectors 146. The third deflector 148 may extend from the first plate 134 toward the inner circumferential surface of the housing 126 (i.e., away from the longitudinal axis A) and toward the downstream end of the housing 126. The third deflector 148 may have a slot 150 formed therein. The second deflectors 146 can deflect the fluid toward the longitudinal axis A and the third deflector 148 deflects the fluid away from the longitudinal axis A. As fluid flows through the housing 126, .

The second plate 136 includes an upstream end 152, a downstream end 154, a plurality of incisions 156, a plurality of first deflectors 158, and a second deflector 160 . The cutouts 156 and the first deflectors 158 may be disposed between the upstream and downstream ends 152, 154. The first deflectors 158 may be partially cut or stamped out of the second plate 136 to form outcrops 156 (to form the cutouts 156) so that the first deflectors 158 2 plate 136 toward the inner peripheral surface of the housing 126 (i.e., away from the longitudinal axis) and toward the upstream end 152 at a predetermined angle. In this manner, as fluids flow from the upstream end 152 to the downstream end 154 through the housing 126, the first deflectors 158 are directed through the cutouts 156 toward the center mixer 130 The fluid can be deflected. The second deflector 160 may be disposed at or adjacent to the downstream end 154 of the second plate 136 and may be located away from the longitudinal axis A from the second plate 136 and downstream of the housing 126 As shown in FIG. The second deflector 160 may be disposed between the second deflectors 146 of the first plate 134. The second deflector 160 may have a slot 162 formed therein. When the fluid flows through the housing 126, the second deflector 160 may deflect the fluid away from the longitudinal axis A. [

The central mixer 130 may include a collar 164 and a plurality of central deflectors 166. The collar 164 may be centered on the longitudinal axis A and may engage the second plates 136 of the first, second, and third deflector groups 127, 128, The central deflectors 166 may be disposed within the collar 164 and may include curved plates that are aligned about the longitudinal axis A. [ The central deflectors 166 may apply a swirling motion to the fluid flowing through the collar 164. In some embodiments, the central deflectors 166 may be approximately S-shaped.

6 to 9, the operation of the mixer 118 will be described in detail. As discussed above, the reductant delivery system 14 may be configured to deliver the reductant from the first, second, and third deflector groups 127, 128, 129 (e.g., via the injector ports 131, 132, 133) A reducing agent can be injected into the exhaust stream. By flowing through the first, second, and third deflector groups 127, 128, and 129, the reducing agent is mixed with the exhaust gas so that as the mixture flows into the post-treatment apparatus 16, More uniformly distributed in the gas.

As shown in FIG. 9, the first, second, and third deflector groups 127, 128, and 129 cause fluid flowing therethrough to form first, second, and third vortex pairs. That is, the first deflector group 127 can generate the first vortex V1 rotating in the counterclockwise direction and the second vortex V2 rotating in the clockwise direction. The second deflector group 128 may generate a third vortex V3 rotating in the clockwise direction and a fourth vortex V4 rotating in the counterclockwise direction. Likewise, the third deflector group 129 can generate a fifth vortex V5 rotating in the clockwise direction and a sixth vortex V6 rotating in the counterclockwise direction. The first and second vortices V1 and V2 may be arranged side by side. The arrangement of the third and fourth vortices V3 and V4 may be rotationally symmetric about the arrangement of the first and second vortices V1 and V2 about the longitudinal axis A. [ Likewise, the arrangement of the fifth and sixth vortices V5, V6 may be rotationally symmetric about the arrangement of the first and second vortices V1, V2 about the longitudinal axis A.

By creating three counter-rotating vortices V1, V2, V3, V4, V5 and V6, the mixer 118 can improve the overall uniformity of the fluid flow pattern on the upstream side of the post-treatment device 16 That is, the flow rate across the upstream surface of post-treatment device 16 may be more uniform). Providing a three-way rotary vortex pair (instead of only one counter-rotating vortex pair) is advantageous because the vortices V1, V2, V3, V4, V5, V6 can be lost before flowing through the after- The distance downstream of the mixer 118 can be reduced. The configuration of the first, second, and third deflector groups 127, 128, and 129 may be particularly advantageous when used with a post-processing apparatus 16 having a triangular cross-section (as shown in FIG. 9) May also be advantageous when used with a post-treatment apparatus having any other shape. For example, the counter-rotating vortex pairs (V1, V2, V3, V4, V5, V6) may be used in conjunction with the post-processing apparatus 16 having a non-circular cross- A mixture of a reducing agent and an exhaust gas may be injected.

As described above, the mixer 118 may include a plurality of injectors 24 for injecting a reducing agent through the injection ports 131, 132, 133. In this way, each injection port 131, 132, 133 may allow the reducing agent to be injected into the corresponding one of the counter-rotating vortex pairs V1, V2, V3, V4, V5, . In some embodiments, most of the reducing agent injected through the first injector port 131 may flow through the first deflector group 127 and most of the reducing agent injected through the second injector port 132 Most of the reducing agent that is injected through the third injector port 133 may flow through the third deflector group 129. [ The injector 24 for each deflector group can provide a more uniform distribution of the reducing agent in the exhaust flow so that each injector 24 corresponding to a particular deflector group 127, Diameter mixer (such as, for example, a mixer having a diameter of 12 inches).

Referring to Figs. 10-13, another mixer 218, which may be incorporated into the system 10, is provided instead of the mixer 18. The mixer 218 includes a housing 226, a first deflector group 227, a second deflector group 228, a third deflector group 229, a fourth deflector group 230, 231). The first, second, third, and fourth deflector groups 227, 228, 229, 230 are positioned about the longitudinal axis A of the housing 226 such that adjacent deflector groups are 90 degrees apart from each other May be arranged in a circular array. That is, the first, second, third, and fourth deflector groups 227, 228, 229, and 230 include first, second, third, and fourth deflector groups 227, 228, 229, 230 may be evenly distributed about the longitudinal axis A so as to form a rotationally symmetric pattern about the longitudinal axis A. [

The housing 226 may be a tubular member including four injection ports 232. Each injection port 232 may be rotationally aligned with a corresponding one of the first, second, third, and fourth deflector groups 227, 228, 229, 230, respectively. As described above, corresponding reducing agent injectors 24 may be accommodated in injection ports 232. [ Although injector ports 232 are shown in the figures as being positioned relative to injectors 24 to atomize the reducing agent in a direction perpendicular to the exhaust gas flow direction, in some embodiments injectors 24 and injector ports 24, The exhaust ports 232 may be positioned at an angle with respect to the exhaust gas flow direction. It is understood that the injectors 24 and injector ports 232 may be located at any location and in any orientation.

The first, second, third, and fourth deflector groups 227, 228, 229, 230 may be substantially similar to each other and include first and second plates 234, 236, can do. The first plate 234 includes an upstream end 238, a downstream end 240, a plurality of incisions 242, a plurality of first deflectors 244, a plurality of second deflectors 246, And a third deflector 248. Cuts 242 and first deflectors 244 may be disposed between the upstream and downstream ends 238, The first deflectors 244 may be partially cut or stamped out of the first plate 234 (to form the cuts 242) so that the first deflectors 244 are bent outwardly 1 plate 234 toward the inner circumferential surface of the housing 226 (i.e., away from the longitudinal axis) and toward the upstream end 238 at an angle. In this manner, when fluid flows from the upstream end 238 to the downstream end 240 through the housing 226, the first deflectors 244 move the second plate 236 through the cutouts 242 The fluid can be deflected toward the < / RTI >

Second deflectors 246 may be disposed at or adjacent to the downstream end 240 of the first plate 234 and may extend from the first plate 234 toward the longitudinal axis A and away from the housing 226 And may extend toward the downstream end. A third deflector 248 may be disposed at or near the downstream end 240 of the first plate 234 and between the second deflectors 246. The third deflector 248 may extend from the first plate 234 toward the inner circumferential surface of the housing 226 (i.e., away from the longitudinal axis A) and toward the downstream end of the housing 226. The third deflector 248 may be formed with a slot 250. The second deflectors 246 may deflect the fluid toward the longitudinal axis A and the third deflector 248 may deflect the fluid away from the longitudinal axis A when the fluid flows through the housing 226. [ .

The second plate 236 includes an upstream end 252, a downstream end 254, a plurality of cutouts 256, a plurality of first deflectors 258, and a second deflector 260 . The cuts 256 and the first deflectors 258 may be disposed between the upstream and downstream ends 252, 254. First deflectors 258 may be partially cut or stamped out of second plate 236 to form outcrops (to form cuts 256) so that first deflectors 258 can be bent outwardly 2 plate 236 toward the inner circumferential surface of the housing 226 (i.e., away from the longitudinal axis) and toward the upstream end 252 at an angle. In this manner, as fluids flow from the upstream end 252 to the downstream end 254 through the housing 226, the first deflectors 258 are directed through the cutouts 256 toward the center mixer 231 The fluid can be deflected. The second deflector 260 may be disposed at or near the downstream end 254 of the second plate 236 and may be located away from the longitudinal axis A from the second plate 236 and downstream of the housing 226 As shown in FIG. The second deflector 260 may be disposed between the second deflectors 246 of the first plate 234. [ The second deflector 260 may have a slot 262 formed therein. When fluid flows through the housing 226, the second deflector 260 can deflect the fluid away from the longitudinal axis A. [

The central mixer 231 includes a plurality of central deflectors 266 that engage the second plates 236 of the first, second, third and fourth deflector groups 227, 228, 229, . The central deflectors 266 may include curved plates that are aligned about the longitudinal axis A. [ The central deflectors 266 are arranged on the fluid flowing through the space defined by the second plates 236 of the first, second, third and fourth deflector groups 227, 228, 229, Vortex motion can be applied. In some embodiments, the central deflectors 266 may be approximately S-shaped.

With continued reference to Figs. 10-13, the operation of the mixer 218 will be described in detail. As discussed above, the reducing agent delivery system 14 may be configured to deliver the reductant to the upstream (e.g., via injector ports 232) of the first, second, third, and fourth deflector groups 227, 228, 229, The reducing agent can be injected into the exhaust stream. By flowing through the first, second, third, and fourth deflector groups 227, 228, 229, 230, the reducing agent is mixed with the exhaust gas so that the mixture flows into the post- The reducing agent is more uniformly distributed in the exhaust gas.

As shown in FIG. 13, the first, second, third and fourth deflector groups 227, 228, 229 and 230 are arranged such that the fluid flowing therethrough passes through first, second, third, To form a vortex pair. That is, the first deflector group 227 can generate the first vortex V1 rotating in the counterclockwise direction and the second vortex V2 rotating in the clockwise direction. The second deflector group 228 may generate a third vortex V3 rotating in the clockwise direction and a fourth vortex V4 rotating in the counterclockwise direction. Similarly, the third deflector group 229 can generate a fifth vortex V5 rotating in the clockwise direction and a sixth vortex V6 rotating in the counterclockwise direction. The fourth deflector group 230 may generate a seventh vortex V7 rotating in the clockwise direction and an eighth vortex V8 rotating in the counterclockwise direction. The first and second vortices V1 and V2 may be arranged side by side. The arrangement of the third and fourth vortices V3 and V4 may be rotationally symmetric about the arrangement of the first and second vortices V1 and V2 about the longitudinal axis A. [ Likewise, the arrangement of the fifth and sixth vortices V5, V6 may be rotationally symmetric about the arrangement of the first and second vortices V1, V2 about the longitudinal axis A. The arrangement of the seventh and eighth vortices V7 and V8 may be rotationally symmetric about the arrangement of the first and second vortices V1 and V2 about the longitudinal axis A. [

By creating four counter-rotating vortices V1, V2, V3, V4, V5, V6, V7 and V8, the mixer 218 improves the overall uniformity of the fluid flow pattern on the upstream side of the post- (I.e., the flow rate across the upstream surface of post-treatment device 16 may be more uniform). V2, V3, V4, V5, V6, V7, and V8 (not just one reverse-rotating vortex pair) before the vortex flows through the post- It is possible to reduce the distance downstream of the mixer 218, which may be lost. The configuration of the first, second, third, and fourth deflector groups 227, 228, 229, 230 may be combined with a post-processing apparatus 16 (as shown in Figure 13) having a square or rectangular cross- May be particularly advantageous when used, but may also be advantageous when used with a post-treatment apparatus having any other shape. V2, V3, V4, V5, V6, V7, and V8 are used in a post-process (e.g., A mixture of reducing agent and exhaust gas may be driven into the corners of the device 16. [

As described above, the mixer 218 may include a plurality of injectors 24 for injecting a reducing agent through a plurality of injection ports 232. In this manner, each injection port 232 may allow the reducing agent to be injected into a corresponding one of the counter-rotating vortex pairs V1, V2, V3, V4, V5, V6, V7, V8 . The injectors 24 for each deflector group may provide a more uniform distribution of the reducing agent in the exhaust flow so that a plurality of injectors 24 corresponding to each particular deflector group 227, 228, 229, Diameter mixer (such as, for example, a mixer having a 12 inch diameter).

14-17, another mixer 318, which may be incorporated into the system 10, is provided instead of the mixer 18. The mixer 318 may include a housing 326 and a plurality of deflector groups 328. 14 to 17, six deflector groups 328 are arranged in a circular array about the longitudinal axis A1 of the housing 326, such that adjacent deflector groups are spaced 60 degrees from one another. . That is, the six deflector groups 328 are evenly distributed about the longitudinal axis A1 so that the six deflector groups 328 form a rotationally symmetric pattern about the longitudinal axis A1. Seventh group 328 may be centered on the longitudinal axis A1 and may be surrounded by another six group of deflectors 328. [ The housing 326 can include one or more injection ports (not shown) that can each receive one or more corresponding reducing agent injectors 24. In some embodiments, the housing 326 may include six injector ports and an injector 24, each corresponding to one of six deflector groups 328 arranged in a circular pattern. As described above, such an arrangement can provide a more uniform distribution of the reducing agent in the exhaust flow.

Each of the deflector groups 328 may be similar or identical to one another and may include a first plate 332, a second plate 334, and a plurality of centers 332, 334 disposed between the first and second plates 332, And a collar 330 surrounding the plate 336. The first, second, and central plates 332, 334, 336 within a particular deflector group 328 may be approximately parallel to one another and may be retained within the slots 337 of the corresponding collar 330. Each deflector group 328 is configured such that the longitudinal axes A2 of the collar 330 are substantially parallel to the longitudinal axis A2 of the housing 326 (or a seventh deflector < RTI ID = 0.0 > Such that the longitudinal axis A2 of the collar 330 may lie on the same straight line as the longitudinal axis A1 for the group 328). However, in some embodiments, the longitudinal axes A2 of the collar 330 may be angled relative to one another and / or about the longitudinal axis A1.

The first plate 332 may include an upstream end 338, a downstream end 340, a plurality of cutouts 342, and a plurality of deflectors 344. [ The cuts 342 and deflectors 344 may be disposed between the upstream and downstream ends 338, 340. The deflectors 344 may be partially cut or stamped out of the first plate 332 to form outcrops (to form the cuts 342) so that the deflectors 344 can be folded out of the first plate 332 (That is, away from the longitudinal axis A2) and toward the upstream end 338 of the collar 330. In this embodiment, In this manner, as fluids flow through the collar 330 from the upstream end 338 to the downstream end 340, the deflectors 344 move fluid through the cutouts 342 toward the center plates 336, .

16), a downstream end 354 (FIG. 17), a plurality of cutouts 356 (FIG. 16), a plurality of first deflectors 358 (FIG. 16), and a second plate 334 And one second deflector 360 (Figures 15 and 17). Cutouts 356 and first deflectors 358 may be disposed between upstream and downstream ends 352, 354. The first deflectors 358 may be partially cut or stamped and bent inward from the second plate 334 (to form cutouts 356) so that the first deflectors 358 can be bent 2 plate 334 toward the longitudinal axis A2 of the collar 330 and toward the downstream end 254 at an angle. The first deflectors 258 can deflect the fluid toward the center plates 336 when the fluid flows from the upstream end 252 to the downstream end 254 through the collar 330 . The second deflector 360 may be disposed at or adjacent to the downstream end 354 of the second plate 334 and may extend from the second plate 334 toward the longitudinal axis A2. The second deflector 360 may have a slot 362 formed therein. When fluid flows through collar 330, second deflector 360 may deflect the fluid toward longitudinal axis A2.

The center plates 336 each have an upstream end 364, a downstream end 366, a plurality of cutouts 368, a plurality of first deflectors 370, a plurality of second deflectors 372, A third deflector 374, The cuts 368 and the first deflectors 370 may be disposed between the upstream and downstream ends 364, 366. The first deflectors 370 may be partially cut or stamped and bent from the center plate 336 (to form cutouts 368) such that the first deflectors 370 are positioned on the center plate 336 toward the first plate 332 and toward the upstream end 364 at an angle. The first deflectors 370 can deflect the fluid through the corresponding cuts 368 when the fluid flows from the upstream end 364 to the downstream end 366 through the collar 330 have.

The second deflectors 372 may be disposed at or adjacent to the downstream end 366 of the center plate 336 and may extend from the center plate 336 toward the second plate 334. A third deflector 374 may be disposed at or near the downstream end 366 of the center plate 336 and between the second deflectors 372. The third deflector 374 may extend from the center plate 336 toward the first plate 332. The third deflector 374 may have a slot 376 formed therein. The second deflectors 372 can deflect the fluid toward the second plate 334 and the third deflector 374 can deflect the fluid from the first plate 332 The fluid can be deflected toward the < / RTI >

With continued reference to Figs. 14 to 17, the operation of the mixer 318 will be described in detail. As discussed above, the reducing agent delivery system 14 may inject a reducing agent into the exhaust stream upstream of the deflector groups 328. [ By flowing through the deflector groups 328, the reducing agent is mixed with the exhaust gas so that as the mixture flows into the post-treatment apparatus 16, the reducing agent is more uniformly distributed in the exhaust gas.

As shown in FIG. 17, each deflector group 328 causes fluid flowing therethrough to form first and second vortex pairs V1, V2 that rotate in opposite directions. By creating seven counter-rotating vortices (V1, V2) (i.e., one pair in each seven deflector groups 328), the mixer 318 is capable of generating a fluid flow pattern (I.e., the flow rate across the upstream surface of post-treatment device 16 may be more uniform). Providing the seven counter-rotating vortex pairs (instead of only one counter-rotating vortex pair) is advantageous in that the vortexes (V1, V2) in the downstream of the mixer 318, which can be lost before flowing through the after- The distance can be reduced. The configuration of the deflector groups 328 may be used with a post-treatment apparatus 16 having, for example, a circular, triangular, square, or rectangular cross section or any other shape of cross section.

The foregoing description of the embodiments has been presented for purposes of illustration and description. This is intended to be exhaustive or is not intended to limit the present disclosure. The individual elements or features of a particular embodiment are not generally limited to this particular embodiment, but may be interchanged, if applicable, and used in selected embodiments, even if not specifically shown or described. It can also be modified in a number of ways. Such modifications are not to be regarded as a departure from the present disclosure, and all such modifications are intended to be included within the scope of this disclosure.

Claims (38)

An exhaust passage for receiving exhaust gas from the engine;
An exhaust post-treatment device disposed in the exhaust passage; And
A mixer including a housing, a first deflector group disposed in the housing, and a second deflector group disposed in the housing, the mixer being disposed in the exhaust passage upstream of the exhaust aftertreatment apparatus, Group is arranged relative to one another to direct fluid flowing through said first deflector group into a first vortex pair rotating in opposite directions with respect to each other, said second deflector group being arranged with respect to said second deflector group The first and second groups of deflectors are arranged about one another to direct the flowing fluid into a second vortex pair rotating in opposite directions relative to each other, the first and second groups of deflectors comprising a mixer rotationally symmetric with respect to each other about a longitudinal axis of the housing The exhaust aftertreatment system. The method according to claim 1,
Wherein the exhaust after-treatment apparatus includes a catalyst. The method according to claim 1,
Further comprising a reducing agent delivery system having a reducing agent injector arranged to inject a reducing agent into the exhaust passage upstream of the first and second deflector groups. The method according to claim 1,
Further comprising a reducing agent delivery system having first and second reducing agent injectors arranged to inject a reducing agent into the exhaust passage upstream of the first and second deflector groups. 5. The method of claim 4,
The housing includes first and second ports for allowing a reducing agent to be injected into the housing from the first and second reducing agent injectors, respectively, wherein the first and second ports are connected to the first port and the second port, Wherein the first deflector group is arranged with respect to the first and second deflector groups so that a reducing agent flows through the first deflector group and most of the reducing agent injected through the second port flows through the second deflector group. Processing system. The method according to claim 1,
The mixer includes a third deflector group disposed in the housing, wherein the third deflector group directs fluid flowing through the third deflector group into a third vortex pair that rotates in opposite directions with respect to each other The exhaust aftertreatment system being arranged relative to one another. The method according to claim 6,
Wherein the first, second, and third deflector groups are rotationally symmetric with respect to each other about the longitudinal axis. 8. The method of claim 7,
Further comprising a central mixer centered on said longitudinal axis and comprising a plurality of deflectors. The method according to claim 6,
The housing includes first, second, and third ports, wherein the first, second, and third ports allow most of the reducing agent injected through the first port to pass through the first deflector group Most of the reducing agent flowing through the second port flows through the second deflector group and most of the reducing agent injected through the third port flows through the third deflector group, 2, and the third deflector group. The method according to claim 6,
Wherein the post-treatment apparatus has a triangular shape. The method according to claim 6,
The mixer includes a fourth deflector group disposed in the housing, wherein the fourth deflector group directs fluid flowing through the fourth deflector group into a fourth vortex pair rotating in opposite directions with respect to each other The exhaust aftertreatment system being arranged relative to one another. 12. The method of claim 11,
Wherein the first, second, third, and fourth deflector groups are rotationally symmetric with respect to each other about the longitudinal axis. 13. The method of claim 12,
Further comprising a central mixer centered on said longitudinal axis and comprising a plurality of deflectors. 12. The method of claim 11,
Wherein the housing comprises first, second, third and fourth ports, wherein the first, second, third and fourth ports are configured such that most of the reducing agent injected through the first port, Most of the reducing agent flowing through the first deflector group and flowing through the second port flows through the second deflector group and most of the reducing agent injected through the third port flows through the third deflector group, Second, third, and fourth deflector groups such that most of the reducing agent injected through the fourth port flows through the fourth deflector group. 12. The method of claim 11,
Wherein the post-treatment apparatus has a square shape. The method according to claim 1,
Wherein each of the first and second groups of deflectors includes a plurality of plates extending parallel to the longitudinal axis of the housing, each plate comprising a plurality of tabs angled with respect to the plate and the longitudinal axis , Exhaust aftertreatment system. 17. The method of claim 16,
The plurality of tabs of each of the plurality of plates includes a plurality of first tabs extending in a first direction from a first side of the corresponding plate and a plurality of second tabs extending in a second direction from a second opposite side of the corresponding plate And a second tab of the exhaust system. The method according to claim 1,
Wherein the housing is a generally tubular member. housing;
A first deflector group disposed in the housing and arranged with respect to each other to direct fluid flowing through the first deflector group into a first vortex pair rotating in a direction opposite to the first deflector group; And
A second deflector group disposed in the housing and configured to direct fluids flowing through the second deflector group into a second vortex pair rotating in opposite directions relative to each other, Including,
Wherein the first and second groups of deflectors are rotationally symmetric with each other about a longitudinal axis of the housing. 20. The method of claim 19,
Wherein the housing includes first and second ports, wherein the first and second ports are configured such that most of the reducing agent injected through the first port flows through the first deflector group and is injected through the second port, Are arranged for the first and second deflector groups such that most of the reducing agent flowing through the second deflector group flows through the second deflector group. 20. The method of claim 19,
Further comprising a third deflector group disposed in the housing such that the third deflector group directs fluid flowing through the third deflector group into a third vortex pair that rotates in an opposite direction with respect to each other A mixer arranged about one another. 22. The method of claim 21,
Wherein the first, second, and third deflector groups are rotationally symmetric with respect to each other about the longitudinal axis. 22. The method of claim 21,
The housing includes first, second, and third ports, wherein the first, second, and third ports allow most of the reducing agent injected through the first port to pass through the first deflector group Most of the reducing agent flowing through the second port flows through the second deflector group and most of the reducing agent injected through the third port flows through the third deflector group, 2, and a third deflector group. 22. The method of claim 21,
Further comprising a fourth deflector group disposed in the housing such that the fourth deflector group directs fluid flowing through the fourth deflector group into a fourth vortex pair that rotates in opposite directions with respect to each other A mixer arranged about one another. 25. The method of claim 24,
Wherein the first, second, third, and fourth deflector groups are rotationally symmetric with respect to each other about the longitudinal axis. 25. The method of claim 24,
Wherein the housing comprises first, second, third and fourth ports, wherein the first, second, third and fourth ports are configured such that most of the reducing agent injected through the first port, Most of the reducing agent flowing through the first deflector group and flowing through the second port flows through the second deflector group and most of the reducing agent injected through the third port flows through the third deflector group, Third, and fourth deflector groups such that most of the reducing agent injected through the fourth port flows through the fourth deflector group. 20. The method of claim 19,
Wherein each of the first and second groups of deflectors includes a plurality of plates extending parallel to the longitudinal axis of the housing, each plate comprising a plurality of tabs angled with respect to the plate and the longitudinal axis , Mixer. 28. The method of claim 27,
The plurality of tabs of each of the plurality of plates includes a plurality of first tabs extending in a first direction from a first side of the corresponding plate and a plurality of second tabs extending in a second direction from a second opposite side of the corresponding plate And a second tab of the mixer. 20. The method of claim 19,
Wherein the housing is a generally tubular member. housing;
A first deflector group disposed within the housing and arranged to generate a first counter-rotating vortex pair; And
A second deflector group disposed within the housing and arranged to generate a second pair of counter-rotating vortices,
Wherein the first and second groups of deflectors are arranged in a circular array about a longitudinal axis of the housing. 31. The method of claim 30,
Further comprising a third deflector group disposed within the housing and arranged to generate a third reverse vortex pair. 32. The method of claim 31,
Wherein the circular array comprises the third deflector group. 32. The method of claim 31,
Further comprising a fourth deflector group disposed within the housing and arranged to generate a fourth counter-rotating vortex pair. 34. The method of claim 33,
Wherein the circular array comprises the fourth deflector group. 35. The method of claim 34,
And a fifth deflector group centered on said longitudinal axis and surrounded by said first, second, third, and fourth deflector groups. 36. The method of claim 35,
Wherein the first, second, third, and fourth deflector groups are rotationally oriented differently from each other. 31. The method of claim 30,
Wherein the first and second deflector groups are surrounded by a first and a second collar, respectively. 39. The method of claim 37,
Said first and second collars each including first and second longitudinal axes that are angled with respect to said longitudinal axis of said housing and with respect to each other.

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