CA2221158C - Static fluid flow mixing apparatus - Google Patents
Static fluid flow mixing apparatus Download PDFInfo
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- CA2221158C CA2221158C CA002221158A CA2221158A CA2221158C CA 2221158 C CA2221158 C CA 2221158C CA 002221158 A CA002221158 A CA 002221158A CA 2221158 A CA2221158 A CA 2221158A CA 2221158 C CA2221158 C CA 2221158C
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- fluid
- flow
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- tabs
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- 239000012530 fluid Substances 0.000 title claims abstract description 147
- 230000003068 static effect Effects 0.000 title claims abstract description 31
- 238000000034 method Methods 0.000 claims description 12
- 238000011144 upstream manufacturing Methods 0.000 claims description 9
- 239000011888 foil Substances 0.000 claims description 8
- 239000012636 effector Substances 0.000 claims description 7
- 230000008901 benefit Effects 0.000 description 3
- 230000000694 effects Effects 0.000 description 2
- 235000012087 Psidium araca Nutrition 0.000 description 1
- 244000233562 Psidium araca Species 0.000 description 1
- 241000220317 Rosa Species 0.000 description 1
- 238000009295 crossflow filtration Methods 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
- B01F25/00—Flow mixers; Mixers for falling materials, e.g. solid particles
- B01F25/40—Static mixers
- B01F25/42—Static mixers in which the mixing is affected by moving the components jointly in changing directions, e.g. in tubes provided with baffles or obstructions
- B01F25/43—Mixing tubes, e.g. wherein the material is moved in a radial or partly reversed direction
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
- B01F25/00—Flow mixers; Mixers for falling materials, e.g. solid particles
- B01F25/40—Static mixers
- B01F25/42—Static mixers in which the mixing is affected by moving the components jointly in changing directions, e.g. in tubes provided with baffles or obstructions
- B01F25/43—Mixing tubes, e.g. wherein the material is moved in a radial or partly reversed direction
- B01F25/431—Straight mixing tubes with baffles or obstructions that do not cause substantial pressure drop; Baffles therefor
- B01F25/4316—Straight mixing tubes with baffles or obstructions that do not cause substantial pressure drop; Baffles therefor the baffles being flat pieces of material, e.g. intermeshing, fixed to the wall or fixed on a central rod
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
- B01F25/00—Flow mixers; Mixers for falling materials, e.g. solid particles
- B01F25/40—Static mixers
- B01F25/42—Static mixers in which the mixing is affected by moving the components jointly in changing directions, e.g. in tubes provided with baffles or obstructions
- B01F25/43—Mixing tubes, e.g. wherein the material is moved in a radial or partly reversed direction
- B01F25/434—Mixing tubes comprising cylindrical or conical inserts provided with grooves or protrusions
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- Chemical & Material Sciences (AREA)
- Dispersion Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Physical Or Chemical Processes And Apparatus (AREA)
Abstract
A static mixer conduit comprising a longitudinally elongated conduit having tabs that are arranged with respective first edges adjacent the conduit wall, and respective opposed second edges that are spaced radially inwardly from the conduit wall. These tabs redirect fluid flow to introduce a radial cross-flow component to the longitudinal flow of fluid through the conduit. A
central body extending generally coaxially along at least a portion of the longitudinal extent of the conduit defines between it and the conduit wall, an annular space confining the radial cross-flow.
central body extending generally coaxially along at least a portion of the longitudinal extent of the conduit defines between it and the conduit wall, an annular space confining the radial cross-flow.
Description
Static Fluid Flow Mixing Apparatus TECffiNICAL FIELD :
The present invention relates to static mixers, and especially to static mixers having both radial and longitudinal flow in an elongated fluid-mixing conduit.
BACKGROUND OF ART :
As a generalization, typical static mixers include fluid redirecting tabs, vanes, baffles or the like, that are arranged in a fluid conduit, and which are typically operable to divide, subdivide, separate adjacent subdivided flows, and then recombine the subdivided flows into a"shuffled" whole, as the fluid passes through that conduit.
In a departure from that more typical approach, US
4,929,088 discloses a tab arrangement in a fluid conduit' that has lower fluid back-pressures than are associated with the more typical approach to more typical static mixer designs. In particular, this patented tab arrangement operates by creating radial vortex flow patterns that are generally transverse to the longitudinal flow through the fluid conduit in which these tabs are mounted. This results in a plurality of cross-stream mixing flows that are transverse to the longitudinal flow of the fluid along the length of the conduit. This approach is disclosed as an enhancement over the kind of mixing that would be expected to naturally occur in a conduit under turbulent fluid flow conditions.
DISCLOSURE OF INVENTION:
In accordance with the present invention there is 3S provided a further improvement in static mixers - one in $d BSTiTltiE SHEET (RULE 261 which a central elongated body is deployed within the static mixer conduit, in a central region of reduced mixing. Such a region, for example, tends to exist between diametrically-opposed, radially-convergent, cross-stream mixing flows within that conduit. In any =
case, this centrally-located body occupies a zone in which there would otherwise be a reduced cross-flow. The presence of this central body results in the fluid flowing past it tending to be more efficiently mixed - in that there is less of a tendency for an unmixed "channel"
of longitudinal fluid flow to establish itself within the centre of the conduit.
In a particularly preferred embodiment according to the present invention, there is provided a static mixer conduit in which tabs are each arranged with respective, (preferably leading, upstream) edges adjacent the conduit wall, and respective, (preferably trailing, downstream) opposed edges that are spaced radially inwardly from the conduit wall. These tabs are operable as fluid foils which, with fluid flowing through the mixer, have greater fluid pressures manifest against their upstream faces and reduced fluid pressures against their downstream faces.
This pressure difference in the fluid adjacent, respectively, the mutually opposed faces of each of the tabs then causes the longitudinal flow over and past each tab to be redirected, thereby resulting in the addition of a radial cross-flow component to the longitudinal flow of fluid through the conduit.
The present invention further includes an improved method, in which the static mixing is performed over a longitudinal extent of a mixing volume having an annular cross-section. More specifically, the method of the present invention relates to cross-stream mixing in a -fluid flow, in which tabs mentioned herein, redirect a longitudinal fluid flow from an outer, fluid containment boundary surface, across an intervening space having an annular cross-section towards an inner boundary surface.
... 3 --Preferably, the tabs are ramped and arranc.~ed in. the fluid flow between the respective boundary surfaces, to cause the fluid to flow over the edges of each such tab to d~-,flect the generally longitudinal f luid flow i:nward:l y f roiri ttie fluid containment boundary surface, across the intervenir.;,g ,.~:-pace (having the aforesaid annular cross-section), towards an inner boundary surface. 'I'he inner boundary surface def.ixlF_s a volume which but for the presence of that surface, would p r.mit passage of a central longitudinal flow of non uni.fozm ~:luid mixing.
In a particularly preferred form tiie fluid flow over the edges of each tab results in the flow be-ir:~~.g deflected inward and up the inclined surface of the tab to generate a pair of tip vortices in the fluid flow past each tab. The vortices of each such pair have mutually opposed rotations, about an axis of rotation oriented generally along the longitudinal "stream-wise" fluid flow direction, along the annular space between the two boundary surfaces.
In accordance with another aspect of the invention there is provided a static mixer conduit including a longitudinally elongated conduit having tabs that are ;-~ec.ured to a conduit wall and that are arranged with respective first edges adjacent the conduit wall, and respective opposed second edges that are spaced radially inwardly from the conduit wall. The tabs are operable as fluid foils which, with flu::ad flowing through the mixer conduit, have greater flu.id pressi.zres manifest against their upstream faces and reduced fluid pressures against their downstream faces. A resultant pressure difference in the fluid adjacent, respectively, the mutual:ly opposi~ec:i faces of each of the tabs causes a longitudinal flow of fluid through the conduit over and past each tab, to be redirected, resulting in the addition of a radial crUss--flow component to the longitudirial flow of' fluid through the conduit. The mixer further includes a central body extending generally coaxially along at least a portion of the longitudinal extent of the 3 a conduit and defiriirig an annular spacf:- between the central body and the conduit wal.l.
In accordance with another aspect :::>f the invention there is provided a static tnixer conduit inc~7udiia(,.1 a lorlgitudinally elongated conduit having tabs that are ~:sec ..ired to a conduit wall and that are arranged with respectIve first edges adjacent the conduit wall, and respective opposed second edges that are spaced inwardly from the conduit wal.:l.. ':Che tabs are operable as fluid foils which, wi t h. fluid f lowing through the mixer conduit, have greater fluid pressures manifest against their upstream faces and reduced fluid pressures against their downstream faces. A resul t:ant pressuz:'e c:ii fterence in the fluid adjacent, respectively, mutually opposed faces of each of the tabs causes a longitudinal flow of fluid through the conduit over and past each tab, to be redirectec:9., resulting in the addition of a cross-flow component tiM> the Longitudinal flow of f:l.uid through the mixer condui.t. The mixer conduit further includes a motionless central body extendi:ng generally coaxially along at least a portion of tlae longitudinally elongated conduit.
In accordance with another aspect of t-he invention there is provided a static mixer conduit including a longitudinally e:Longated conduit having tabs that are arranged with respective first edges adjacent the conduit wall, and respecti.ve opposed second edges that are spaced radially inwardly from the conduit wall. The tabs are operable as fluid foils which, with fluid f:Lowing through said mixer conduit:, have greater fluid pressures manifest against their u.pstream faces and reduced fluid pressures against their downstream faces. A resultant pressure difference in the fluid adjacent, respectively, the mutually opposed faces of: each of the tabs causes a longitudinal flow of fluid through the conduit over and past each tab, to be redirected, resulting in the addition of a radial cross-flow component to the longituiiinal flow of fluid 3b .
through the conduit_ The inixer further :irrcludes a motionless ceritral body, inc:Luding d~~rosE~, f lc~w .Ei.Lt-,tr element, extending gerierally coaxial:Ly along at lt:.aast a poa._t:ion of the longitudinal extent. of trle co:czdl.z.it: araca dei ining an annular space between the central body and t.he, 4.-(-)n.duit wall.
In accordance with another aspect of t'rie invention there is provided a method including static rn:a..xing over a longitudinal exterit of a mixing volume having an annular cross-section, where radial cross-stx-eam ma.x:iric; in a 1.ongit:udinal fluid flow results from f low-direct. inc:l t:,A;,s redirect:ing a longitudinal flow from an outer, fluid containment boundary surface to which tabs are secured, by redirecting the longitudinal flow across ari intervening space having an annular cross-section towards a motionless inner boundary surface.
In accordance with another aspect r.,i: the invention there iis provided a method inc:luding static mi.x.ing, over a longitudinal extent of a mixing volume having an annular cross-section, wherein radial cross-stream mixing in a longitudinal fluid flow results from ilow-directing t..abs redirecting a longitudinal flow from an outer, fluid containment boundary surface by redirecting tlie longitudinal flow across an intervening space having an aririular, c.ross-secti.on towards a motionless inner boundarv surface. The tabs may be ramped and arranged in the fluid flow between the :reslaective boundary surfaces, to cause the fluid to flow over the edges of each tab to deflect the generally longitudinal fluid flow inwardly from the fluid containment boundary surface, ac:k-oss the irrtervening annular space towards the inner boundary surface. The fluid f:Low over the edges of each tab results in the flow being deflected inwardly and upwardly along an inclined surface of each tab, to generate a pair of tip vortices in the fluid flow past each tab. The vortices associated witii each pair have mutually opposed rotat.ioris about an axis of rotation oriented generally along the longitudinal. "stream-w.ise" fluid flow - ic -direction, along the annular space between the two boundary surfaces.
In accordance with anothel aspect:()1= the invention there is provided a flow-through rea(..,t::c>r for t:reating a fluid. The reactor includes: A) a fluid conducting channel ; B) a central body providing an inner boundary surface substantially centrally located within the channel; arid ;.,1 static fluid-dynamic-effector mearis positioned in t.hf:_, channel for deflecting the flow of a fluid through the channe~l. 'Trie effect(Dr means include a plurality of mot:ion::le.:>s, ramped tabs having inclined surfaces and trailing downstream edges c,:lirected inwardly into the channel toward the inner boundary surface to permit a longitudinal fluid flow in a space between the downstream edges and the inner boundary surface. The tabs provide cross-stream mixin(g in the longitudinal fla.zid flow by deflecting the fluid over the edges of eack-i of the tabs inwardly and upwardly along the inclined surface toward the inner boundary surface, generating a pair of tip vortices in the longitudinal fluid flow past each tab, each vortex of each of the pair of tip v(Drtices being mutually opposed in rotation about an axis of rotation oriented along the longitudinal fl.uid flow and along the space between the edges and the inner boundary surface.
In accordance with another aspect of the invention there is provided a method for treating a fluid by flowing the fluid through a flow-through reactor. The reactor includes: A) a fluid conducting channel; E) a central body providing an inner b(Dundary surface substantially centrally located within the channel; and C) static f,~~.ui.d-dynarnic-effector means positioned in the channel for deflecting the flow of a fluid through the channel. The effector means include a plurality of motionless, ramped tabs having inclined surfaces and trailing downstream edges directed inwardly into the channel tcDward the iriner boundary surface to permit a longitudina.:l f'luid flow in a space between the downstream edges and, the inner boundary surface.
3 d The tabs provide cross-stream niixirig :in t:he longitudinal fluid flow by deflecting the fluid over the edq(~:~s of each of the tabs inwardly and upwardly along the inclined surface toward the inner boundary surface thereby generatiaig a pair of tip vortices in the lon.gitud.ina:l. :flui.d flow past, each tab, each vortex of each of the pa:ii:, of tip vort:::i.c:es being mutually opposed in rotation about an axis c-~f rot.at:ion oriented along the longitudinal fluid flow and along the space between the edges and the inner boundary surface.
In alternative embodiments of the ~.r~,-~r.i.ous aspects of the invention, the central body of t::he stat.i(- mixer condi,zit. may include a cross-flow filter element, or niay include a heat t:ransfer body adapted to exchange heat with the fluid passing t'zrough the conduit.
BRIEF DESCRIPTION OF DRAWINGS:
Figure 1 is an elevated, longitudinal cross-section through a static mixer according t.c) the combination of the present invention;
Figure 2 is an elevated, transverse cross-section taken through line 2-2 of the rnixer depicted in Figure 1;
Figure 3 is a reproduction of th.e view illustrated in Figure 2, but further including representative fluid stream lines, to illustrate radial cross--flow patterns;
and, Figure 4 is a cut-away perspective view illustrating vortex flow downstream of a single, representative tab.
The present invention relates to static mixers, and especially to static mixers having both radial and longitudinal flow in an elongated fluid-mixing conduit.
BACKGROUND OF ART :
As a generalization, typical static mixers include fluid redirecting tabs, vanes, baffles or the like, that are arranged in a fluid conduit, and which are typically operable to divide, subdivide, separate adjacent subdivided flows, and then recombine the subdivided flows into a"shuffled" whole, as the fluid passes through that conduit.
In a departure from that more typical approach, US
4,929,088 discloses a tab arrangement in a fluid conduit' that has lower fluid back-pressures than are associated with the more typical approach to more typical static mixer designs. In particular, this patented tab arrangement operates by creating radial vortex flow patterns that are generally transverse to the longitudinal flow through the fluid conduit in which these tabs are mounted. This results in a plurality of cross-stream mixing flows that are transverse to the longitudinal flow of the fluid along the length of the conduit. This approach is disclosed as an enhancement over the kind of mixing that would be expected to naturally occur in a conduit under turbulent fluid flow conditions.
DISCLOSURE OF INVENTION:
In accordance with the present invention there is 3S provided a further improvement in static mixers - one in $d BSTiTltiE SHEET (RULE 261 which a central elongated body is deployed within the static mixer conduit, in a central region of reduced mixing. Such a region, for example, tends to exist between diametrically-opposed, radially-convergent, cross-stream mixing flows within that conduit. In any =
case, this centrally-located body occupies a zone in which there would otherwise be a reduced cross-flow. The presence of this central body results in the fluid flowing past it tending to be more efficiently mixed - in that there is less of a tendency for an unmixed "channel"
of longitudinal fluid flow to establish itself within the centre of the conduit.
In a particularly preferred embodiment according to the present invention, there is provided a static mixer conduit in which tabs are each arranged with respective, (preferably leading, upstream) edges adjacent the conduit wall, and respective, (preferably trailing, downstream) opposed edges that are spaced radially inwardly from the conduit wall. These tabs are operable as fluid foils which, with fluid flowing through the mixer, have greater fluid pressures manifest against their upstream faces and reduced fluid pressures against their downstream faces.
This pressure difference in the fluid adjacent, respectively, the mutually opposed faces of each of the tabs then causes the longitudinal flow over and past each tab to be redirected, thereby resulting in the addition of a radial cross-flow component to the longitudinal flow of fluid through the conduit.
The present invention further includes an improved method, in which the static mixing is performed over a longitudinal extent of a mixing volume having an annular cross-section. More specifically, the method of the present invention relates to cross-stream mixing in a -fluid flow, in which tabs mentioned herein, redirect a longitudinal fluid flow from an outer, fluid containment boundary surface, across an intervening space having an annular cross-section towards an inner boundary surface.
... 3 --Preferably, the tabs are ramped and arranc.~ed in. the fluid flow between the respective boundary surfaces, to cause the fluid to flow over the edges of each such tab to d~-,flect the generally longitudinal f luid flow i:nward:l y f roiri ttie fluid containment boundary surface, across the intervenir.;,g ,.~:-pace (having the aforesaid annular cross-section), towards an inner boundary surface. 'I'he inner boundary surface def.ixlF_s a volume which but for the presence of that surface, would p r.mit passage of a central longitudinal flow of non uni.fozm ~:luid mixing.
In a particularly preferred form tiie fluid flow over the edges of each tab results in the flow be-ir:~~.g deflected inward and up the inclined surface of the tab to generate a pair of tip vortices in the fluid flow past each tab. The vortices of each such pair have mutually opposed rotations, about an axis of rotation oriented generally along the longitudinal "stream-wise" fluid flow direction, along the annular space between the two boundary surfaces.
In accordance with another aspect of the invention there is provided a static mixer conduit including a longitudinally elongated conduit having tabs that are ;-~ec.ured to a conduit wall and that are arranged with respective first edges adjacent the conduit wall, and respective opposed second edges that are spaced radially inwardly from the conduit wall. The tabs are operable as fluid foils which, with flu::ad flowing through the mixer conduit, have greater flu.id pressi.zres manifest against their upstream faces and reduced fluid pressures against their downstream faces. A resultant pressure difference in the fluid adjacent, respectively, the mutual:ly opposi~ec:i faces of each of the tabs causes a longitudinal flow of fluid through the conduit over and past each tab, to be redirected, resulting in the addition of a radial crUss--flow component to the longitudirial flow of' fluid through the conduit. The mixer further includes a central body extending generally coaxially along at least a portion of the longitudinal extent of the 3 a conduit and defiriirig an annular spacf:- between the central body and the conduit wal.l.
In accordance with another aspect :::>f the invention there is provided a static tnixer conduit inc~7udiia(,.1 a lorlgitudinally elongated conduit having tabs that are ~:sec ..ired to a conduit wall and that are arranged with respectIve first edges adjacent the conduit wall, and respective opposed second edges that are spaced inwardly from the conduit wal.:l.. ':Che tabs are operable as fluid foils which, wi t h. fluid f lowing through the mixer conduit, have greater fluid pressures manifest against their upstream faces and reduced fluid pressures against their downstream faces. A resul t:ant pressuz:'e c:ii fterence in the fluid adjacent, respectively, mutually opposed faces of each of the tabs causes a longitudinal flow of fluid through the conduit over and past each tab, to be redirectec:9., resulting in the addition of a cross-flow component tiM> the Longitudinal flow of f:l.uid through the mixer condui.t. The mixer conduit further includes a motionless central body extendi:ng generally coaxially along at least a portion of tlae longitudinally elongated conduit.
In accordance with another aspect of t-he invention there is provided a static mixer conduit including a longitudinally e:Longated conduit having tabs that are arranged with respective first edges adjacent the conduit wall, and respecti.ve opposed second edges that are spaced radially inwardly from the conduit wall. The tabs are operable as fluid foils which, with fluid f:Lowing through said mixer conduit:, have greater fluid pressures manifest against their u.pstream faces and reduced fluid pressures against their downstream faces. A resultant pressure difference in the fluid adjacent, respectively, the mutually opposed faces of: each of the tabs causes a longitudinal flow of fluid through the conduit over and past each tab, to be redirected, resulting in the addition of a radial cross-flow component to the longituiiinal flow of fluid 3b .
through the conduit_ The inixer further :irrcludes a motionless ceritral body, inc:Luding d~~rosE~, f lc~w .Ei.Lt-,tr element, extending gerierally coaxial:Ly along at lt:.aast a poa._t:ion of the longitudinal extent. of trle co:czdl.z.it: araca dei ining an annular space between the central body and t.he, 4.-(-)n.duit wall.
In accordance with another aspect of t'rie invention there is provided a method including static rn:a..xing over a longitudinal exterit of a mixing volume having an annular cross-section, where radial cross-stx-eam ma.x:iric; in a 1.ongit:udinal fluid flow results from f low-direct. inc:l t:,A;,s redirect:ing a longitudinal flow from an outer, fluid containment boundary surface to which tabs are secured, by redirecting the longitudinal flow across ari intervening space having an annular cross-section towards a motionless inner boundary surface.
In accordance with another aspect r.,i: the invention there iis provided a method inc:luding static mi.x.ing, over a longitudinal extent of a mixing volume having an annular cross-section, wherein radial cross-stream mixing in a longitudinal fluid flow results from ilow-directing t..abs redirecting a longitudinal flow from an outer, fluid containment boundary surface by redirecting tlie longitudinal flow across an intervening space having an aririular, c.ross-secti.on towards a motionless inner boundarv surface. The tabs may be ramped and arranged in the fluid flow between the :reslaective boundary surfaces, to cause the fluid to flow over the edges of each tab to deflect the generally longitudinal fluid flow inwardly from the fluid containment boundary surface, ac:k-oss the irrtervening annular space towards the inner boundary surface. The fluid f:Low over the edges of each tab results in the flow being deflected inwardly and upwardly along an inclined surface of each tab, to generate a pair of tip vortices in the fluid flow past each tab. The vortices associated witii each pair have mutually opposed rotat.ioris about an axis of rotation oriented generally along the longitudinal. "stream-w.ise" fluid flow - ic -direction, along the annular space between the two boundary surfaces.
In accordance with anothel aspect:()1= the invention there is provided a flow-through rea(..,t::c>r for t:reating a fluid. The reactor includes: A) a fluid conducting channel ; B) a central body providing an inner boundary surface substantially centrally located within the channel; arid ;.,1 static fluid-dynamic-effector mearis positioned in t.hf:_, channel for deflecting the flow of a fluid through the channe~l. 'Trie effect(Dr means include a plurality of mot:ion::le.:>s, ramped tabs having inclined surfaces and trailing downstream edges c,:lirected inwardly into the channel toward the inner boundary surface to permit a longitudinal fluid flow in a space between the downstream edges and the inner boundary surface. The tabs provide cross-stream mixin(g in the longitudinal fla.zid flow by deflecting the fluid over the edges of eack-i of the tabs inwardly and upwardly along the inclined surface toward the inner boundary surface, generating a pair of tip vortices in the longitudinal fluid flow past each tab, each vortex of each of the pair of tip v(Drtices being mutually opposed in rotation about an axis of rotation oriented along the longitudinal fl.uid flow and along the space between the edges and the inner boundary surface.
In accordance with another aspect of the invention there is provided a method for treating a fluid by flowing the fluid through a flow-through reactor. The reactor includes: A) a fluid conducting channel; E) a central body providing an inner b(Dundary surface substantially centrally located within the channel; and C) static f,~~.ui.d-dynarnic-effector means positioned in the channel for deflecting the flow of a fluid through the channel. The effector means include a plurality of motionless, ramped tabs having inclined surfaces and trailing downstream edges directed inwardly into the channel tcDward the iriner boundary surface to permit a longitudina.:l f'luid flow in a space between the downstream edges and, the inner boundary surface.
3 d The tabs provide cross-stream niixirig :in t:he longitudinal fluid flow by deflecting the fluid over the edq(~:~s of each of the tabs inwardly and upwardly along the inclined surface toward the inner boundary surface thereby generatiaig a pair of tip vortices in the lon.gitud.ina:l. :flui.d flow past, each tab, each vortex of each of the pa:ii:, of tip vort:::i.c:es being mutually opposed in rotation about an axis c-~f rot.at:ion oriented along the longitudinal fluid flow and along the space between the edges and the inner boundary surface.
In alternative embodiments of the ~.r~,-~r.i.ous aspects of the invention, the central body of t::he stat.i(- mixer condi,zit. may include a cross-flow filter element, or niay include a heat t:ransfer body adapted to exchange heat with the fluid passing t'zrough the conduit.
BRIEF DESCRIPTION OF DRAWINGS:
Figure 1 is an elevated, longitudinal cross-section through a static mixer according t.c) the combination of the present invention;
Figure 2 is an elevated, transverse cross-section taken through line 2-2 of the rnixer depicted in Figure 1;
Figure 3 is a reproduction of th.e view illustrated in Figure 2, but further including representative fluid stream lines, to illustrate radial cross--flow patterns;
and, Figure 4 is a cut-away perspective view illustrating vortex flow downstream of a single, representative tab.
HEST MODE(S) FOR CARRYING OUT TH8 INVMTION
AND INDUS'T'RIAL APPLIGAHILITY :
(Note: The apparatus disclosed and illustrated in US
4,929,088 - Smith, (dar.ed March 29, 1990), is useful as a component of the present invention, as well as the method described i.n US
4,981,368 - Smith, (dated January 1, 1991).
2.0 iteforring now to Figures 1, 2 and 3, there is illustrated an embodiment according to the pxesent tnvention, in which a static tnixer. 1. includes a series of tabs 2 that are secured to the side walls 3 of a conduit 4. A central body 5 is arranged in co-axially aligned relation, centrally within the interior of conduit 4, where it occupies a region of inefficient mixing.
In the illustrated embodiment, that region forms between diametricall.y==opposed, radia:l.lyWconvergerYt, cross=strcanm mixing flowb (see Figure 3, in particular) within conduit 4.
Static mixer 1 comprises conduit 4, in which tabs 2 are each arranged with respecti=re, (leading, upstream) edges 6 adjacent the conduit wall, and respective, (trailing, downstream) opposed edges 7 that are spaced radially inwardly from the conduit wa1l. 3. Tabs 2 operate as fluid foils which, with fluid flowing through the mixer, have greater fluid pressures manifest against their upstream faces 8 (see Figure 1) and reduced fluid pressures against their downstream faces 9(see Figure 1).
This pressure dif.ference in the fluid adjacent, respectiv2ely, the mutually opposed faces of each of the tabs then causes the longitudinal flow over and past each tab to be redirected (as is illustrated by the various flow streamlines that are shown in the various figures), thereby resulting in the addition of a radial cross-flow component to the longitudinal flow of fluid through the conduit 4.
With body 5 occupying the zone of relatively poor mixing as described above, the fluid itself is precluded from forming eddies in that zone, in which the fluid would not be as thoroughly admixed with the balance of the fluid flow.
In a particularly preferred embodiment, body 5 comprises a heat transfer body, adapted to exchange heat with the fluid passing through the conduit. This allows an manufacturer to not only secure improved mixing as aforesaid, but to also increase the amount of heat exchange surface available to alter the temperature of the fluid flow. This is particularly advantageous since the benefit of avoiding boundary layer "insulation"
effects as discussed in relation to the boundary surface described in US 4,929,088, is true for both that boundary surface, and for the heat exchange surface of the central body S.
In a further embodiment according to the present invention, the central body 5 is a cross-flow filter element. As will be apparent to persons skilled in the art, in light of the present invention, the boundary layer advantages associated with thermal transfer are applicable in achieving cross-flow filtration advantages too.
In operation, the improved static mixing according to the present invention is performed over a longitudinal extent of a mixing volume having an annular cross-section, located between the central body 5 and side walls 3 of conduit 4. More specifically, there is cross-stream mixing in the longitudinal fluid flow through the present apparatus, in which tabs 2 redirect a longitudinal fluid flow from the outer, fluid containment boundary surface of side walls 3, across an intervening space having an annular cross-section towards the inner - 6 - ~
boundary surface defining the outermost extent of central body S. Preferably, tabs 2 are ramped and arranged in the fluid flow between the respective boundary surfaces of side walls 3 and central body 5, to cause the fluid to flow over the edges of each tab 2 to deflect the generally longitudinal fluid flow radially inwardly from the fluid containment boundary surface of side wall 3, across the intervening space (having the aforesaid annular cross-section), towards an inner boundary surface defined by the outermost surface of central body 5. The inner boundary surface of central body 5, circumscribes a volume which but for the presence of that surface, would permit passage of a central longitudinal flow of substantial, relatively non-uniform mixing.
In a particularly preferred form the fluid flow over the edges of each tab results in the flow being deflected inward and up the inclined surface of the tab to generate a pair of tip vortices in the fluid flow past each tab.
The vortices of each such pair have mutually opposed rotations, about an axis of rotation oriented generally along the longitudinal "stream-wise" fluid flow direction, along the annular space between the two boundary surfaces.
AND INDUS'T'RIAL APPLIGAHILITY :
(Note: The apparatus disclosed and illustrated in US
4,929,088 - Smith, (dar.ed March 29, 1990), is useful as a component of the present invention, as well as the method described i.n US
4,981,368 - Smith, (dated January 1, 1991).
2.0 iteforring now to Figures 1, 2 and 3, there is illustrated an embodiment according to the pxesent tnvention, in which a static tnixer. 1. includes a series of tabs 2 that are secured to the side walls 3 of a conduit 4. A central body 5 is arranged in co-axially aligned relation, centrally within the interior of conduit 4, where it occupies a region of inefficient mixing.
In the illustrated embodiment, that region forms between diametricall.y==opposed, radia:l.lyWconvergerYt, cross=strcanm mixing flowb (see Figure 3, in particular) within conduit 4.
Static mixer 1 comprises conduit 4, in which tabs 2 are each arranged with respecti=re, (leading, upstream) edges 6 adjacent the conduit wall, and respective, (trailing, downstream) opposed edges 7 that are spaced radially inwardly from the conduit wa1l. 3. Tabs 2 operate as fluid foils which, with fluid flowing through the mixer, have greater fluid pressures manifest against their upstream faces 8 (see Figure 1) and reduced fluid pressures against their downstream faces 9(see Figure 1).
This pressure dif.ference in the fluid adjacent, respectiv2ely, the mutually opposed faces of each of the tabs then causes the longitudinal flow over and past each tab to be redirected (as is illustrated by the various flow streamlines that are shown in the various figures), thereby resulting in the addition of a radial cross-flow component to the longitudinal flow of fluid through the conduit 4.
With body 5 occupying the zone of relatively poor mixing as described above, the fluid itself is precluded from forming eddies in that zone, in which the fluid would not be as thoroughly admixed with the balance of the fluid flow.
In a particularly preferred embodiment, body 5 comprises a heat transfer body, adapted to exchange heat with the fluid passing through the conduit. This allows an manufacturer to not only secure improved mixing as aforesaid, but to also increase the amount of heat exchange surface available to alter the temperature of the fluid flow. This is particularly advantageous since the benefit of avoiding boundary layer "insulation"
effects as discussed in relation to the boundary surface described in US 4,929,088, is true for both that boundary surface, and for the heat exchange surface of the central body S.
In a further embodiment according to the present invention, the central body 5 is a cross-flow filter element. As will be apparent to persons skilled in the art, in light of the present invention, the boundary layer advantages associated with thermal transfer are applicable in achieving cross-flow filtration advantages too.
In operation, the improved static mixing according to the present invention is performed over a longitudinal extent of a mixing volume having an annular cross-section, located between the central body 5 and side walls 3 of conduit 4. More specifically, there is cross-stream mixing in the longitudinal fluid flow through the present apparatus, in which tabs 2 redirect a longitudinal fluid flow from the outer, fluid containment boundary surface of side walls 3, across an intervening space having an annular cross-section towards the inner - 6 - ~
boundary surface defining the outermost extent of central body S. Preferably, tabs 2 are ramped and arranged in the fluid flow between the respective boundary surfaces of side walls 3 and central body 5, to cause the fluid to flow over the edges of each tab 2 to deflect the generally longitudinal fluid flow radially inwardly from the fluid containment boundary surface of side wall 3, across the intervening space (having the aforesaid annular cross-section), towards an inner boundary surface defined by the outermost surface of central body 5. The inner boundary surface of central body 5, circumscribes a volume which but for the presence of that surface, would permit passage of a central longitudinal flow of substantial, relatively non-uniform mixing.
In a particularly preferred form the fluid flow over the edges of each tab results in the flow being deflected inward and up the inclined surface of the tab to generate a pair of tip vortices in the fluid flow past each tab.
The vortices of each such pair have mutually opposed rotations, about an axis of rotation oriented generally along the longitudinal "stream-wise" fluid flow direction, along the annular space between the two boundary surfaces.
Claims (14)
1. A static mixer conduit comprising a longitudinally elongated conduit having tabs that are secured to a conduit wall and that are arranged with respective first edges adjacent the conduit, wall, and respective opposed second edges that are spaced radially inwardly, from the conduit wall, wherein said tabs are operable as fluid foils which, with fluid flowing through said mixer conduit, have greater fluid pressures manifest against their upstream faces and reduced fluid pressures against their downstream faces, and wherein a resultant pressure difference in the fluid adjacent, respectively, the mutually opposed faces of each of the tabs causes a longitudinal flow of fluid through said conduit over and past each said tab, to be redirected, thereby resulting in the addition of a radial cross-flow component to the longitudinal flow of fluid through the conduit, and wherein said mixer further comprises a central body extending generally coaxially along at least a portion of the longitudinal extent of said conduit and defining between said central body and said conduit wall, an annular space.
2. A static mixer conduit comprising a longitudinally elongated conduit having tabs that are secured to a conduit wall and that are arranged with respective first edges adjacent said conduit wall, and respective opposed second edges that are spaced inwardly from the conduit wall, wherein said tabs are operable as fluid foils which, with fluid flowing through said mixer conduit, have greater fluid pressures manifest against their upstream faces and reduced fluid pressures against their downstream faces, and wherein a resultant pressure difference in said fluid adjacent, respectively, mutually opposed faces of each of said tabs causes a longitudinal flow of fluid through said conduit over and past each said tab, to be redirected, thereby resulting in the addition of a cross-flow component to the longitudinal flow of fluid through said mixer conduit, and wherein said mixer conduit further comprises a motionless central body extending generally coaxially along at least a portion of said longitudinally elongated conduit.
3. The static mixer conduit of claim 2, wherein the central body comprises a cross-flow filter element.
4. The static mixer conduit of any one of claims 1-3, wherein the central body comprises a heat transfer body adapted to exchange heat with the fluid passing through the conduit.
5. A static mixer conduit comprising a longitudinally elongated conduit having tabs that are arranged with respective first edges adjacent the conduit wall, and respective opposed second edges that are spaced radially inwardly from the conduit wall, wherein said tabs are operable as fluid foils which, with fluid flowing through said mixer conduit, have greater fluid pressures manifest against their upstream faces and reduced fluid pressures against their downstream faces, and wherein a resultant pressure difference in the fluid adjacent, respectively, the mutually opposed faces of each of the tabs causes a longitudinal flow of fluid through said conduit over and past each said tab, to be redirected, thereby resulting in the addition of a radial cross-flow component to the longitudinal flow of fluid through the conduit, and wherein said mixer, further comprises a motionless central body, comprising a cross-flow filter element, extending generally coaxially along at least a portion of the longitudinal extent of said conduit and defining between said central body and said conduit wall, an annular space.
6. A method comprising static mixing, over a longitudinal extent of a mixing volume having an annular cross-section, wherein radial cross-stream mixing and in a longitudinal fluid flow results from flow-directing tabs redirecting a longitudinal flow from an outer, containment boundary surface to which tabs are secured, comprising redirecting said longitudinal flow across an intervening space having an annular cross-section towards a motionless inner boundary surface.
7. The method according to claim 6, wherein said tabs are ramped and arranged in the fluid flow between the respective boundary surfaces, to cause the fluid to flow over the edges of each said tab to deflect the generally longitudinal fluid flow inwardly from the fluid containment boundary surface, across the intervening annular space towards said inner boundary surface.
8. A method comprising static mixing, over a longitudinal extent of a mixing volume having an annular cross-section, wherein radial cross-stream mixing in a longitudinal fluid flow results from flow-directing tabs redirecting a longitudinal flow from an outer, fluid containment boundary surface, wherein said tabs are ramped and arranged in the fluid flow between the respective boundary surfaces, to cause the fluid to flow over the edges of each said tab to deflect the generally longitudinal fluid flow inwardly from the fluid containment boundary surface, across the intervening annular space towards said inner boundary surface, wherein the fluid flow over the edges of each said tab results in the flow being deflected inwardly and upwardly along an inclined surface of each said tab, to thereby generate a pair of tip in the fluid flow past each tab, and wherein said vortices associated with each said pair have mutually opposed rotations about an axis of rotation oriented generally along the longitudinal "stream-wise"
fluid flow direction, along the annular space between said two boundary surfaces, comprising redirecting said longitudinal flow across an intervening space having an annular cross-section towards a motionless inner boundary surface.
fluid flow direction, along the annular space between said two boundary surfaces, comprising redirecting said longitudinal flow across an intervening space having an annular cross-section towards a motionless inner boundary surface.
9. A flow-through reactor for treating a fluid therein, said reactor comprising:
A) a fluid conducting channel;
B) a central body providing an inner boundary surface substantially centrally located within said channel;
and C) static fluid-dynamic-effector means positioned in said channel for deflecting the flow of a fluid through said channel, said effector means comprising a plurality of motionless, ramped tabs having inclined surfaces and trailing downstream edges directed inwardly into said channel toward said inner boundary surface to permit a longitudinal fluid flow in a space between said downstream edges and said inner boundary surface, said tabs providing cross-stream mixing in said longitudinal fluid flow by deflecting said fluid over said edges of each of said tabs inwardly and upwardly along said inclined surface toward said inner boundary surface thereby generating a pair of tip vortices in said longitudinal fluid flow past each tab, each vortex of each of said pair of tip vortices being mutually opposed in rotation about an axis of rotation oriented along said longitudinal fluid flow and along said space between said edges and said inner boundary surface.
A) a fluid conducting channel;
B) a central body providing an inner boundary surface substantially centrally located within said channel;
and C) static fluid-dynamic-effector means positioned in said channel for deflecting the flow of a fluid through said channel, said effector means comprising a plurality of motionless, ramped tabs having inclined surfaces and trailing downstream edges directed inwardly into said channel toward said inner boundary surface to permit a longitudinal fluid flow in a space between said downstream edges and said inner boundary surface, said tabs providing cross-stream mixing in said longitudinal fluid flow by deflecting said fluid over said edges of each of said tabs inwardly and upwardly along said inclined surface toward said inner boundary surface thereby generating a pair of tip vortices in said longitudinal fluid flow past each tab, each vortex of each of said pair of tip vortices being mutually opposed in rotation about an axis of rotation oriented along said longitudinal fluid flow and along said space between said edges and said inner boundary surface.
10. The reactor of claim 9, wherein the central body is a heat transfer body.
11. The reactor of claim 9 or 10, wherein the central body is a cross-flow filter element.
12. A method for treating a fluid comprising flowing said fluid through a flow-through reactor, said reactor comprising:
A) a fluid conducting channel;
B) a central body providing an inner boundary surface substantially centrally located within said channel;
and C) static fluid-dynamic-effector means positioned in said channel for deflecting the flow of a fluid through said channel; said effector means comprising a plurality of motionless, ramped tabs having inclined surfaces and trailing downstream edges directed inwardly into said channel toward said inner boundary surface to permit a longitudinal fluid flow in a space between said downstream edges and said inner boundary surface, said tabs providing cross-stream mixing in said longitudinal fluid flow by deflecting said fluid over said edges of each of said tabs inwardly and upwardly along said inclined surface toward said inner boundary surface thereby generating a pair of tip vortices in said longitudinal fluid flow past each tab, each vortex of each of said pair of tip vortices being mutually opposed in rotation about an axis of rotation oriented along said longitudinal fluid flow and along said space between said edges and said inner boundary surface.
A) a fluid conducting channel;
B) a central body providing an inner boundary surface substantially centrally located within said channel;
and C) static fluid-dynamic-effector means positioned in said channel for deflecting the flow of a fluid through said channel; said effector means comprising a plurality of motionless, ramped tabs having inclined surfaces and trailing downstream edges directed inwardly into said channel toward said inner boundary surface to permit a longitudinal fluid flow in a space between said downstream edges and said inner boundary surface, said tabs providing cross-stream mixing in said longitudinal fluid flow by deflecting said fluid over said edges of each of said tabs inwardly and upwardly along said inclined surface toward said inner boundary surface thereby generating a pair of tip vortices in said longitudinal fluid flow past each tab, each vortex of each of said pair of tip vortices being mutually opposed in rotation about an axis of rotation oriented along said longitudinal fluid flow and along said space between said edges and said inner boundary surface.
13. The method of claim 1-2, wherein the central body is a heat transfer body.
14. The method of claim 12 or 13, wherein, the central body is a cross-flow filter element
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US43823595A | 1995-05-09 | 1995-05-09 | |
| US08/438,235 | 1995-05-09 | ||
| PCT/CA1996/000302 WO1996035506A1 (en) | 1995-05-09 | 1996-05-09 | Static fluid flow mixing apparatus |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2221158A1 CA2221158A1 (en) | 1996-11-14 |
| CA2221158C true CA2221158C (en) | 2006-08-08 |
Family
ID=36791749
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002221158A Expired - Fee Related CA2221158C (en) | 1995-05-09 | 1996-05-09 | Static fluid flow mixing apparatus |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2221158C (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2324290A2 (en) * | 2008-08-21 | 2011-05-25 | Riley Power, Inc. | Deflector device for coal piping systems |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8082860B2 (en) | 2008-04-30 | 2011-12-27 | Babcock Power Services Inc. | Anti-roping device for pulverized coal burners |
| US20210308640A1 (en) * | 2018-09-20 | 2021-10-07 | Stefan F. Meili | Fluid mixing device |
-
1996
- 1996-05-09 CA CA002221158A patent/CA2221158C/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2324290A2 (en) * | 2008-08-21 | 2011-05-25 | Riley Power, Inc. | Deflector device for coal piping systems |
| EP2324290A4 (en) * | 2008-08-21 | 2011-08-03 | Riley Power Inc | Deflector device for coal piping systems |
Also Published As
| Publication number | Publication date |
|---|---|
| CA2221158A1 (en) | 1996-11-14 |
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