CA1257196A - Agitators - Google Patents
AgitatorsInfo
- Publication number
- CA1257196A CA1257196A CA000529394A CA529394A CA1257196A CA 1257196 A CA1257196 A CA 1257196A CA 000529394 A CA000529394 A CA 000529394A CA 529394 A CA529394 A CA 529394A CA 1257196 A CA1257196 A CA 1257196A
- Authority
- CA
- Canada
- Prior art keywords
- blades
- rotor
- assembly according
- sparging
- fluid
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
- B01F23/00—Mixing according to the phases to be mixed, e.g. dispersing or emulsifying
- B01F23/20—Mixing gases with liquids
- B01F23/23—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids
- B01F23/233—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids using driven stirrers with completely immersed stirring elements
- B01F23/2331—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids using driven stirrers with completely immersed stirring elements characterised by the introduction of the gas along the axis of the stirrer or along the stirrer elements
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
- B01F23/00—Mixing according to the phases to be mixed, e.g. dispersing or emulsifying
- B01F23/20—Mixing gases with liquids
- B01F23/23—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids
- B01F23/233—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids using driven stirrers with completely immersed stirring elements
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
- B01F23/00—Mixing according to the phases to be mixed, e.g. dispersing or emulsifying
- B01F23/20—Mixing gases with liquids
- B01F23/23—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids
- B01F23/233—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids using driven stirrers with completely immersed stirring elements
- B01F23/2331—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids using driven stirrers with completely immersed stirring elements characterised by the introduction of the gas along the axis of the stirrer or along the stirrer elements
- B01F23/23311—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids using driven stirrers with completely immersed stirring elements characterised by the introduction of the gas along the axis of the stirrer or along the stirrer elements through a hollow stirrer axis
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
- B01F23/00—Mixing according to the phases to be mixed, e.g. dispersing or emulsifying
- B01F23/20—Mixing gases with liquids
- B01F23/23—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids
- B01F23/233—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids using driven stirrers with completely immersed stirring elements
- B01F23/2331—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids using driven stirrers with completely immersed stirring elements characterised by the introduction of the gas along the axis of the stirrer or along the stirrer elements
- B01F23/23314—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids using driven stirrers with completely immersed stirring elements characterised by the introduction of the gas along the axis of the stirrer or along the stirrer elements through a hollow stirrer element
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
- B01F23/00—Mixing according to the phases to be mixed, e.g. dispersing or emulsifying
- B01F23/20—Mixing gases with liquids
- B01F23/23—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids
- B01F23/233—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids using driven stirrers with completely immersed stirring elements
- B01F23/2336—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids using driven stirrers with completely immersed stirring elements characterised by the location of the place of introduction of the gas relative to the stirrer
- B01F23/23362—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids using driven stirrers with completely immersed stirring elements characterised by the location of the place of introduction of the gas relative to the stirrer the gas being introduced under the stirrer
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
- B01F27/00—Mixers with rotary stirring devices in fixed receptacles; Kneaders
- B01F27/05—Stirrers
- B01F27/11—Stirrers characterised by the configuration of the stirrers
- B01F27/112—Stirrers characterised by the configuration of the stirrers with arms, paddles, vanes or blades
- B01F27/1123—Stirrers characterised by the configuration of the stirrers with arms, paddles, vanes or blades sickle-shaped, i.e. curved in at least one direction
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
- B01F27/00—Mixers with rotary stirring devices in fixed receptacles; Kneaders
- B01F27/05—Stirrers
- B01F27/11—Stirrers characterised by the configuration of the stirrers
- B01F27/112—Stirrers characterised by the configuration of the stirrers with arms, paddles, vanes or blades
- B01F27/1125—Stirrers characterised by the configuration of the stirrers with arms, paddles, vanes or blades with vanes or blades extending parallel or oblique to the stirrer axis
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
- B01F27/00—Mixers with rotary stirring devices in fixed receptacles; Kneaders
- B01F27/05—Stirrers
- B01F27/11—Stirrers characterised by the configuration of the stirrers
- B01F27/115—Stirrers characterised by the configuration of the stirrers comprising discs or disc-like elements essentially perpendicular to the stirrer shaft axis
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
- B01F27/00—Mixers with rotary stirring devices in fixed receptacles; Kneaders
- B01F27/05—Stirrers
- B01F27/11—Stirrers characterised by the configuration of the stirrers
- B01F27/19—Stirrers with two or more mixing elements mounted in sequence on the same axis
- B01F27/192—Stirrers with two or more mixing elements mounted in sequence on the same axis with dissimilar elements
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Mixers Of The Rotary Stirring Type (AREA)
- Crystals, And After-Treatments Of Crystals (AREA)
- Accessories For Mixers (AREA)
- Liquid Crystal Substances (AREA)
- Mixers With Rotating Receptacles And Mixers With Vibration Mechanisms (AREA)
Abstract
ABSTRACT
A turbine agitator assembly comprising a reservoir for liquid, a rotor mounted in the reservoir and with a plurality of radially extending blades, and means for sparging a fluid into liquid in the reservoir, the fluid sparging means and the rotor being so constructed and arranged that, in use, the rotor blades (submerged in the liquid) and/or the liquid flow they generate disperse the sparged fluid, characterised in that each of the blades is hollow and has a discontinuous leading edge, only a single trailing edge along an acute angle, no external conclave surface and an open radially outer end.
A turbine agitator assembly comprising a reservoir for liquid, a rotor mounted in the reservoir and with a plurality of radially extending blades, and means for sparging a fluid into liquid in the reservoir, the fluid sparging means and the rotor being so constructed and arranged that, in use, the rotor blades (submerged in the liquid) and/or the liquid flow they generate disperse the sparged fluid, characterised in that each of the blades is hollow and has a discontinuous leading edge, only a single trailing edge along an acute angle, no external conclave surface and an open radially outer end.
Description
- AGITATORS
~his invention relates to agitator~ for the dispersion of a fluid in a liquid.
Disc turbine agitators with a plurality of axially aligned plane paddle blades are known for the dispersion of sparged gases as small bubbles in liquids in tanks and the conco~itant mixing of the tank contents. In u6e, a vorte~ low pressure zone forms behind each rotating blade of the turbine, and with the gas flow rates frequently encountered in industry, the - 10 gas tends to collect and be held as a cavity in this ~one, this disadvantageously reduces dispersion and ~ixing efficiency and can cause turbine blade erosion.
The same problem would be found with a sparged liquid less dense than the tank liquid. We have now designed a turbine agitator in which vortex formation and its deleterious consequences are minimised, and which provides eEficient dispersion and mixingO
Accordingly, the present invention provides a turbine agitator assembly comprising a reservoir for liquid, a rotor mounted in the re~er~oir and with a plurality of radially extending blades, and ~eans for sparging a fluid into li~uid in the reservoir, the fluid sparging ~eans and the rotor being so constructed and arranged that, in use, the rotor blades (submergea in the liquid~ and/or the liquid flow they generate disperse the sparged fluid, - characterised in tha~ each of the blades i~ hollow and ha6 a discontinuous leading edge, only a 6ingle
~his invention relates to agitator~ for the dispersion of a fluid in a liquid.
Disc turbine agitators with a plurality of axially aligned plane paddle blades are known for the dispersion of sparged gases as small bubbles in liquids in tanks and the conco~itant mixing of the tank contents. In u6e, a vorte~ low pressure zone forms behind each rotating blade of the turbine, and with the gas flow rates frequently encountered in industry, the - 10 gas tends to collect and be held as a cavity in this ~one, this disadvantageously reduces dispersion and ~ixing efficiency and can cause turbine blade erosion.
The same problem would be found with a sparged liquid less dense than the tank liquid. We have now designed a turbine agitator in which vortex formation and its deleterious consequences are minimised, and which provides eEficient dispersion and mixingO
Accordingly, the present invention provides a turbine agitator assembly comprising a reservoir for liquid, a rotor mounted in the re~er~oir and with a plurality of radially extending blades, and ~eans for sparging a fluid into li~uid in the reservoir, the fluid sparging ~eans and the rotor being so constructed and arranged that, in use, the rotor blades (submergea in the liquid~ and/or the liquid flow they generate disperse the sparged fluid, - characterised in tha~ each of the blades i~ hollow and ha6 a discontinuous leading edge, only a 6ingle
-2-trailing edge along an acute angle, no external concave surface and an open radially outer end.
In conventional disc turbine agitator6, we have found that vortices are generated where fluid flow i6 not streamline along the blade surface, but becGmes 'separated', for example at projecting edgas ~e.g. ~he ;~ axial edges of conventional a~ially-aligned paddle blades), where a trailing external surface i~ concave, or where there iB no acute trailing edge, e.g. with circular, elliptioal, ~quare or oblong cross-section blades.
We believe that any blade fulfilling the foregoing criteria for a blade of this invention will be suitable. Within this, the blade may have a 15 symmetrical cross-section, having a circular, parabolic or elliptical section leading face merging smoothly into a sphenoidal (i.e. wedge 6haped) or sharply elongate parabolic or elliptical section trailing part.
It will be seen that the term 'trailing edge along an 20 acute angle' thus includes both angular and sharply radiused edges. Parabolic or elliptical seotion ~ leading ~aces are favoured as improving the streamline - around the blade, although the leading part may also be sphenoidal. A preferred blade shape is a symmetrical 25 aerofoil-like cross-seotion.
~he blade is hollow and the leading edge is discontinuou~, for ~xample in the form of holes, or in the preferred form of a slot symmetrically disposed in the leading face of a symmetrical cross-section blade.
30 The radially outer end of the blade is at l~a~t partially open, 80 that ~uch a blade provides a scooping action which disperses and mixes by pumping the ~cooped liquid radially outwardsO
Typical dimensions of a blade in the present assembly are:
blade length = D/4, projected height = D/5, where D is the overall rotor diameter.
Typically the blade will be made of conventional ~etals or plastics used for turbine agitator paddles.
In its general $orm the blade has two elongate axes, one radial and one transverse, de~ining a 'blade plane'. q~is blade plane will generally coincide with or lie parallel to any plane oE rotation describea by the blade in use, that is the blade is usually not set at an 'attack angle' on or with respect to the rotor shaft. However, this latter possibility is not excluded, but the skilled man will readily appreciate that the angle ~hould not be so great that the trailing (or any leading~ edge behaves effectively as an axially projecting edge, and/or any trailing part of the blade surface behaves effectively as a concave surface, in tending to produce substantial vortices.
The blades of the turbine rotor ~ay be arranged in the same rotational plane or in any number of parallel rotational planes. It i6 preferred that the blade are arranged regularly within any one plane so that rotational balance is maxi~ised. Preferably they are also ~as apt) so arranged along the shaft and with respect to each blade in any other plane in accordance with routine engineerin~ practi~e that tor ional balance is maximised, for example, they are arranged with equal numbers of blades in each plane~ and with corresponding blades in different planes axially in register or with all the pla~es regularly rotationally skewed with respect to one another.
The blades may also be set at any angle to the rotor shaft in an axial direction, other than a right angle in order to provide an axial component of the discharge flow.
The rotor may have 2 or more blades. The mixing efficiency of the turbine will generally increa.se with the number of blades in any one plane until such point that the blades are BO close with respect to their transverse dimension that in use the action of any one blade interferes with the action of the following blade. Similarly the useful number of planes of blades i8 ]imited by any mutual interference between the planes due to proximityO The addition of further planes of blades increasingly remote from a single axial sparging eource may also not increase the fluide disper6ing efficiency of the turbine, but may 6till assist mixing of the liquid and/or liquid fluid dispersion in the reservoir.
Subject to the foregoing suitable blade numbers include 2 to 24 coplanar blades, typically 4 to 12, and up~to 5 planes of blades, typically 1.
Typically, dimensions of the rotor are deter~ined by the size of the reservoir, and u~ually -the diameter will be one third to a half the corre~ponding reservoir transverse dimension.
The fluid ~parging means may have a single : - \
- aperture, or multiple apertures ~uch as a row, grid, rose or ring. Although the 6parging of liquids, in particular those les~ dense than the reservoir liquids, is not excluded, the sparged fluid will often be a gas.
The rotor and fluid sparging means may be placed in any orientation and mutual position which ensures that the fluid is delivered either to the volume swept by the rotor blades or to any dixectly adjacent 30ne on which any liquid 10w generated by the rotor blades impinges (in both cases 'the dispersion ~one').
The rotor may be mounted in any orien~ation, although it will often be convenient to mount it upright with the sparging means mounted on the reservoir above or below it, e.g. spaced axially from it, so that the fluid may be delivered to the dispersion zone through the liquid essentially under gravity, either from below for a gas or liquid less - dense than the reservoir liquid or ~rom above for a denser liquid. The sparging means may then suitably be a hole, rose or ring coaxial with the rotor.
As is common with turbine agitators the blades will not generally extend from the rotor shaft itself but will each be ~ounted on an ar~ or an equivalent structure on the shaft. It will be apparent that an axial hole, rose or ring sparging means small diameter than the overall rotor aiameter which does not overlap the blades will ~ot deliver fluid to the dispersion zone without a deflector. In ~uch a case the blades may conveniently be mounted extending from the periphery of a rotor disc, the disc acting as a ~ -6- ~ 6 deflector. With the typical blade dimentions given hereinbe~ore, the disc will typically be 3D/4 in diameter, where D is the overall rotor diameter.
The fluid may of course be delivered to a zone radially outside the volume swept by the blades, since the liquid pumped into this zone by the blades makes it a dispersion ~one; a sparging ring may ~e used.
Alternatively, the rotor may be mounted cross-wise with the sparging means mounted on the reservoir and spaced radially from it above or below, ayain conveniently to allow delivexy essentially under gravity. The sparging means may then suitably be an axially aligned row, a transverse straiyht or arcuate row or a planar or curved grid depending on the rotor structure.
In another aspect the sparging means may be mounted on the rotor, for example as an aperture or apertures in front of each blade or spaced axially from the or a blade planeu Orientations of the rotor appropriate to or compatible with the disposition of the sparging means and blades will be self-~vident to the skilled man.
Although useful in all applications where dispersion of two fluid phases is required, the present assembly is particularly use~ul for gas-liquid mass transfer processes, and for low-shear thorough mixing, e.g. of sensitive substrates such as living cell fermentation su~pensions or polymer latices or dispersions subject to ready degradation or coagulation.
The pre ent invention will now be de~cribed with 9~
: reference to three specific embodiment~ of the rotor and sparging means, depicted in Figure~ 1, 2, 3 and 4.
In the Figures, a rotor 4 iB rotata~Iy mounted vertically within a reservoir 2 (not shown~ capable of holding a liquid 3 (also not 6hown) to sub~erge the rotor 4. The rotor 4 consi~t~ o~ a sha~t 5 (driven by an electric motor 6 - not 6hown) on which a plurality (four or 8iX) radially extending blades 7 are mounted regularly about the shaft 5 in a ~ingle plane by means of a disc or arms 8.
Each blade 7 is of symmetrical uniform aerofoil cros~-section with a single sphenoidal acute-angle trailing edge 9 extending the length of the blade 7.
Each blade 7 is hollow and its leading face 10 has a symmetically disposed slot 11 extending the length of : the blade 7. The ends 12 of the blade 7 are open.
The blades 7 are mounted such that their central planes ~ of sy~metry are coplanar.
: A means for sparging gas 14 is, in Figures 1 to ~: 20 3, mounted on the reservoir below the level of and coaxial with the rotor. In Figures 1 and 2 it i~ a ~ingle aperture or a sparging ring of apertures which do not overlap the blades 7. In Figure 3 it is a sparging ring lying below a zone 19 radially outside the volu~e 18 swept by the blades in use. In Figure 4 the sparging means 14 ¢onsists of four apertured tubes mounted on, projecting from, and communicating with the ; hollow interior of the shaft 5, and regularly spread betweén and coplanar with the blades 6. ~heir apertureB 15 are in the trailing face 16 of each tube 14 .
- In use, the reservoir 2 is filled with liquid 3 to sub~erge the blades 7 of the rotor 4, which is ~hen rotated in the direction of arrow A. Gas 17 i5 then supplied via sparging apertures 15 (in Figure 4 through the hollow interior of the rotor shaft 5 and rod~ 13) to the volume 18 swept by the blades ~in Figure 1 by deflection by the disc 8) or the zon~ 19. In all cases liquid 3 is scooped in by the blades 7 through the ~lot 11 and discharged through the open blade end`12 i~to the dispersion zone 19. In Figures 1, 2 and 4 the gas 17 flows ove~ the outer surface of the blades 7, and in all cases the gas is dispersed in the zone 19.
In conventional disc turbine agitator6, we have found that vortices are generated where fluid flow i6 not streamline along the blade surface, but becGmes 'separated', for example at projecting edgas ~e.g. ~he ;~ axial edges of conventional a~ially-aligned paddle blades), where a trailing external surface i~ concave, or where there iB no acute trailing edge, e.g. with circular, elliptioal, ~quare or oblong cross-section blades.
We believe that any blade fulfilling the foregoing criteria for a blade of this invention will be suitable. Within this, the blade may have a 15 symmetrical cross-section, having a circular, parabolic or elliptical section leading face merging smoothly into a sphenoidal (i.e. wedge 6haped) or sharply elongate parabolic or elliptical section trailing part.
It will be seen that the term 'trailing edge along an 20 acute angle' thus includes both angular and sharply radiused edges. Parabolic or elliptical seotion ~ leading ~aces are favoured as improving the streamline - around the blade, although the leading part may also be sphenoidal. A preferred blade shape is a symmetrical 25 aerofoil-like cross-seotion.
~he blade is hollow and the leading edge is discontinuou~, for ~xample in the form of holes, or in the preferred form of a slot symmetrically disposed in the leading face of a symmetrical cross-section blade.
30 The radially outer end of the blade is at l~a~t partially open, 80 that ~uch a blade provides a scooping action which disperses and mixes by pumping the ~cooped liquid radially outwardsO
Typical dimensions of a blade in the present assembly are:
blade length = D/4, projected height = D/5, where D is the overall rotor diameter.
Typically the blade will be made of conventional ~etals or plastics used for turbine agitator paddles.
In its general $orm the blade has two elongate axes, one radial and one transverse, de~ining a 'blade plane'. q~is blade plane will generally coincide with or lie parallel to any plane oE rotation describea by the blade in use, that is the blade is usually not set at an 'attack angle' on or with respect to the rotor shaft. However, this latter possibility is not excluded, but the skilled man will readily appreciate that the angle ~hould not be so great that the trailing (or any leading~ edge behaves effectively as an axially projecting edge, and/or any trailing part of the blade surface behaves effectively as a concave surface, in tending to produce substantial vortices.
The blades of the turbine rotor ~ay be arranged in the same rotational plane or in any number of parallel rotational planes. It i6 preferred that the blade are arranged regularly within any one plane so that rotational balance is maxi~ised. Preferably they are also ~as apt) so arranged along the shaft and with respect to each blade in any other plane in accordance with routine engineerin~ practi~e that tor ional balance is maximised, for example, they are arranged with equal numbers of blades in each plane~ and with corresponding blades in different planes axially in register or with all the pla~es regularly rotationally skewed with respect to one another.
The blades may also be set at any angle to the rotor shaft in an axial direction, other than a right angle in order to provide an axial component of the discharge flow.
The rotor may have 2 or more blades. The mixing efficiency of the turbine will generally increa.se with the number of blades in any one plane until such point that the blades are BO close with respect to their transverse dimension that in use the action of any one blade interferes with the action of the following blade. Similarly the useful number of planes of blades i8 ]imited by any mutual interference between the planes due to proximityO The addition of further planes of blades increasingly remote from a single axial sparging eource may also not increase the fluide disper6ing efficiency of the turbine, but may 6till assist mixing of the liquid and/or liquid fluid dispersion in the reservoir.
Subject to the foregoing suitable blade numbers include 2 to 24 coplanar blades, typically 4 to 12, and up~to 5 planes of blades, typically 1.
Typically, dimensions of the rotor are deter~ined by the size of the reservoir, and u~ually -the diameter will be one third to a half the corre~ponding reservoir transverse dimension.
The fluid ~parging means may have a single : - \
- aperture, or multiple apertures ~uch as a row, grid, rose or ring. Although the 6parging of liquids, in particular those les~ dense than the reservoir liquids, is not excluded, the sparged fluid will often be a gas.
The rotor and fluid sparging means may be placed in any orientation and mutual position which ensures that the fluid is delivered either to the volume swept by the rotor blades or to any dixectly adjacent 30ne on which any liquid 10w generated by the rotor blades impinges (in both cases 'the dispersion ~one').
The rotor may be mounted in any orien~ation, although it will often be convenient to mount it upright with the sparging means mounted on the reservoir above or below it, e.g. spaced axially from it, so that the fluid may be delivered to the dispersion zone through the liquid essentially under gravity, either from below for a gas or liquid less - dense than the reservoir liquid or ~rom above for a denser liquid. The sparging means may then suitably be a hole, rose or ring coaxial with the rotor.
As is common with turbine agitators the blades will not generally extend from the rotor shaft itself but will each be ~ounted on an ar~ or an equivalent structure on the shaft. It will be apparent that an axial hole, rose or ring sparging means small diameter than the overall rotor aiameter which does not overlap the blades will ~ot deliver fluid to the dispersion zone without a deflector. In ~uch a case the blades may conveniently be mounted extending from the periphery of a rotor disc, the disc acting as a ~ -6- ~ 6 deflector. With the typical blade dimentions given hereinbe~ore, the disc will typically be 3D/4 in diameter, where D is the overall rotor diameter.
The fluid may of course be delivered to a zone radially outside the volume swept by the blades, since the liquid pumped into this zone by the blades makes it a dispersion ~one; a sparging ring may ~e used.
Alternatively, the rotor may be mounted cross-wise with the sparging means mounted on the reservoir and spaced radially from it above or below, ayain conveniently to allow delivexy essentially under gravity. The sparging means may then suitably be an axially aligned row, a transverse straiyht or arcuate row or a planar or curved grid depending on the rotor structure.
In another aspect the sparging means may be mounted on the rotor, for example as an aperture or apertures in front of each blade or spaced axially from the or a blade planeu Orientations of the rotor appropriate to or compatible with the disposition of the sparging means and blades will be self-~vident to the skilled man.
Although useful in all applications where dispersion of two fluid phases is required, the present assembly is particularly use~ul for gas-liquid mass transfer processes, and for low-shear thorough mixing, e.g. of sensitive substrates such as living cell fermentation su~pensions or polymer latices or dispersions subject to ready degradation or coagulation.
The pre ent invention will now be de~cribed with 9~
: reference to three specific embodiment~ of the rotor and sparging means, depicted in Figure~ 1, 2, 3 and 4.
In the Figures, a rotor 4 iB rotata~Iy mounted vertically within a reservoir 2 (not shown~ capable of holding a liquid 3 (also not 6hown) to sub~erge the rotor 4. The rotor 4 consi~t~ o~ a sha~t 5 (driven by an electric motor 6 - not 6hown) on which a plurality (four or 8iX) radially extending blades 7 are mounted regularly about the shaft 5 in a ~ingle plane by means of a disc or arms 8.
Each blade 7 is of symmetrical uniform aerofoil cros~-section with a single sphenoidal acute-angle trailing edge 9 extending the length of the blade 7.
Each blade 7 is hollow and its leading face 10 has a symmetically disposed slot 11 extending the length of : the blade 7. The ends 12 of the blade 7 are open.
The blades 7 are mounted such that their central planes ~ of sy~metry are coplanar.
: A means for sparging gas 14 is, in Figures 1 to ~: 20 3, mounted on the reservoir below the level of and coaxial with the rotor. In Figures 1 and 2 it i~ a ~ingle aperture or a sparging ring of apertures which do not overlap the blades 7. In Figure 3 it is a sparging ring lying below a zone 19 radially outside the volu~e 18 swept by the blades in use. In Figure 4 the sparging means 14 ¢onsists of four apertured tubes mounted on, projecting from, and communicating with the ; hollow interior of the shaft 5, and regularly spread betweén and coplanar with the blades 6. ~heir apertureB 15 are in the trailing face 16 of each tube 14 .
- In use, the reservoir 2 is filled with liquid 3 to sub~erge the blades 7 of the rotor 4, which is ~hen rotated in the direction of arrow A. Gas 17 i5 then supplied via sparging apertures 15 (in Figure 4 through the hollow interior of the rotor shaft 5 and rod~ 13) to the volume 18 swept by the blades ~in Figure 1 by deflection by the disc 8) or the zon~ 19. In all cases liquid 3 is scooped in by the blades 7 through the ~lot 11 and discharged through the open blade end`12 i~to the dispersion zone 19. In Figures 1, 2 and 4 the gas 17 flows ove~ the outer surface of the blades 7, and in all cases the gas is dispersed in the zone 19.
Claims (10)
1. A turbine agitator assembly comprising a reservoir for liquid, a rotor mounted in the reservoir and with a plurality of radially extending blades, and means for sparging a fluid into liquid in the reservoir, the fluid sparging means and the rotor being so constructed and arranged that, in use, the rotor blades (submerged in the liquid) and/or the liquid flow they generate disperse the sparged fluid, characterised in that each of the blades is hollow and has a discontinuous edge, only a single trailing edge along an acute angle, no external concave surface and an open radially outer end.
2. An assembly according to claim 1, wherein each blade has a symmetrical aerofoil-like cross-section with a parabolic or elliptical section leading face merging smoothly into a sphenoidal trailing part.
3. An assembly according to claim 2 having a slot symmetrically disposed in the leading face.
4. An assembly according to claim 2 wherein the blade plane coincides with or lies parallel to the plane of rotation of the blade in use.
5. An assembly according to claim 1 wherein the blades are arranged regularly in the same rotational plane or in each of a number of parallel rotational planes.
6. An assembly according to claim 5 the blades are arranged in a number of parallel rotational planes having the same number of blades in each plane and corresponding blades in different planes axially in register or with all the planes regularly rotationally skewed with respect to one another.
7. An assembly according to claim 5 having 4 to 12 blades in a single rotational plane.
8. An assembly according to claim 1 wherein the blades are mounted on a horizontal rotor disc and the assembly is so arranged that in use the disc serves to deflect the sparging fluid to the volume swept by the blades.
9. An assembly according to claim 1 wherein the sparging means is so arranged in use it delivers the sparging fluid to a zone radially outside the volume swept by the blades.
10. An assembly according to claim 1 wherein the sparging means is mounted on the rotor.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8603904 | 1986-02-17 | ||
| GB868603904A GB8603904D0 (en) | 1986-02-17 | 1986-02-17 | Agitators |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1257196A true CA1257196A (en) | 1989-07-11 |
Family
ID=10593203
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000529394A Expired CA1257196A (en) | 1986-02-17 | 1987-02-10 | Agitators |
Country Status (12)
| Country | Link |
|---|---|
| EP (1) | EP0234768B1 (en) |
| JP (1) | JPS62193635A (en) |
| AT (1) | ATE83169T1 (en) |
| AU (1) | AU580702B2 (en) |
| CA (1) | CA1257196A (en) |
| DE (1) | DE3782951T2 (en) |
| ES (1) | ES2037078T3 (en) |
| GB (1) | GB8603904D0 (en) |
| HK (1) | HK1001041A1 (en) |
| IE (1) | IE60597B1 (en) |
| NZ (1) | NZ219280A (en) |
| ZA (1) | ZA87882B (en) |
Families Citing this family (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0441505A1 (en) * | 1990-02-05 | 1991-08-14 | Imperial Chemical Industries Plc | Agitators |
| GB2268420B (en) * | 1992-07-04 | 1995-11-29 | Flow Research Evaluation Diagn | Improvements relating to liquid treatment apparatus |
| US5791780A (en) * | 1997-04-30 | 1998-08-11 | Chemineer, Inc. | Impeller assembly with asymmetric concave blades |
| JP2003010664A (en) * | 2001-07-03 | 2003-01-14 | Kawata Mfg Co Ltd | Mixing device for powdery/granular material |
| DE10336054B4 (en) * | 2003-08-01 | 2005-12-15 | Domo Caproleuna Gmbh | Process for the preparation of hydroxylammonium salts |
| DE102007001711A1 (en) * | 2007-01-11 | 2008-07-17 | EKATO Rühr- und Mischtechnik GmbH | Stirring arrangement with a stirrer and a gassing device |
| US20080199321A1 (en) * | 2007-02-16 | 2008-08-21 | Spx Corporation | Parabolic radial flow impeller with tilted or offset blades |
| CN103958041B (en) * | 2011-11-24 | 2016-10-19 | 王利 | There is the agitator arm of blade paddle shape |
| US11136958B2 (en) | 2012-08-06 | 2021-10-05 | Nederlandse Organisatie Voor Toegepast-Natuurwetenschappelijk Onderzoek Tno | Swallow tail airfoil |
| NL2009286C2 (en) * | 2012-08-06 | 2014-02-10 | Stichting Energie | Swallow tail airfoil. |
| CN102974504B (en) * | 2012-12-06 | 2016-05-18 | 济南圣泉集团股份有限公司 | A kind of anti-precipitation coating machine |
| JP2014136203A (en) * | 2013-01-18 | 2014-07-28 | Chugoku Electric Power Co Inc:The | Agitator |
| DE102013002060A1 (en) * | 2013-02-07 | 2014-08-07 | Wilfried Rummel | Apparatus for producing colloidal fluids with a colloidation vessel and method |
| JP5898297B2 (en) * | 2014-11-20 | 2016-04-06 | グローバルアドバンストメタルジャパン株式会社 | Method for producing nitrogen-containing metal powder |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2207144A1 (en) * | 1972-02-16 | 1973-08-30 | Schoeller Bleckmann Stahlwerke | Liquid aerating appts - using vanes with determined gas exit width to vane width ratio |
| AU502018B2 (en) * | 1976-05-04 | 1979-07-12 | United States Filter Corporation | Mixing apparatus |
| US4159181A (en) * | 1976-12-23 | 1979-06-26 | American Pelletizing Corporation | Mixing and pelletizing machine |
| AU509477B2 (en) * | 1977-09-05 | 1980-05-15 | Gousti International Ltd. | Mixing apparatus |
| US4305673A (en) * | 1980-03-25 | 1981-12-15 | General Signal Corporation | High efficiency mixing impeller |
| JPS5724624A (en) * | 1980-07-18 | 1982-02-09 | Shozo Urashi | Vapor-liquid contact apparatus |
| JPS5759625A (en) * | 1980-09-29 | 1982-04-10 | Yoichi Nagase | Stirring blade |
| SE461444B (en) * | 1985-11-21 | 1990-02-19 | Boerje Skaanberg | IMPELLER APPLIED FOR THE STIRRING OF FLUID DURING DISPERSION OF GAS THEREOF |
-
1986
- 1986-02-17 GB GB868603904A patent/GB8603904D0/en active Pending
-
1987
- 1987-02-02 EP EP87300911A patent/EP0234768B1/en not_active Expired - Lifetime
- 1987-02-02 AT AT87300911T patent/ATE83169T1/en not_active IP Right Cessation
- 1987-02-02 ES ES198787300911T patent/ES2037078T3/en not_active Expired - Lifetime
- 1987-02-02 DE DE8787300911T patent/DE3782951T2/en not_active Expired - Lifetime
- 1987-02-03 IE IE27987A patent/IE60597B1/en not_active IP Right Cessation
- 1987-02-06 ZA ZA87882A patent/ZA87882B/en unknown
- 1987-02-10 CA CA000529394A patent/CA1257196A/en not_active Expired
- 1987-02-13 AU AU68764/87A patent/AU580702B2/en not_active Ceased
- 1987-02-16 NZ NZ219280A patent/NZ219280A/en unknown
- 1987-02-17 JP JP62032568A patent/JPS62193635A/en active Pending
-
1997
- 1997-12-09 HK HK97102369A patent/HK1001041A1/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| ZA87882B (en) | 1987-10-28 |
| HK1001041A1 (en) | 1998-05-22 |
| AU580702B2 (en) | 1989-01-27 |
| DE3782951T2 (en) | 1993-07-08 |
| EP0234768A2 (en) | 1987-09-02 |
| NZ219280A (en) | 1988-10-28 |
| IE60597B1 (en) | 1994-07-27 |
| JPS62193635A (en) | 1987-08-25 |
| ES2037078T3 (en) | 1993-06-16 |
| GB8603904D0 (en) | 1986-03-26 |
| DE3782951D1 (en) | 1993-01-21 |
| EP0234768A3 (en) | 1989-04-26 |
| IE870279L (en) | 1987-08-17 |
| EP0234768B1 (en) | 1992-12-09 |
| AU6876487A (en) | 1987-08-20 |
| ATE83169T1 (en) | 1992-12-15 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |